RESTOP: Retaining External Peripheral State in Intermittently-Powered Sensor Systems.

Science.gov (United States)

Rodriguez Arreola, Alberto; Balsamo, Domenico; Merrett, Geoff V; Weddell, Alex S

2018-01-10

Energy harvesting sensor systems typically incorporate energy buffers (e.g., rechargeable batteries and supercapacitors) to accommodate fluctuations in supply. However, the presence of these elements limits the miniaturization of devices. In recent years, researchers have proposed a new paradigm, transient computing, where systems operate directly from the energy harvesting source and allow computation to span across power cycles, without adding energy buffers. Various transient computing approaches have addressed the challenge of power intermittency by retaining the processor's state using non-volatile memory. However, no generic approach has yet been proposed to retain the state of peripherals external to the processing element. This paper proposes RESTOP, flexible middleware which retains the state of multiple external peripherals that are connected to a computing element (i.e., a microcontroller) through protocols such as SPI or I 2 C. RESTOP acts as an interface between the main application and the peripheral, which keeps a record, at run-time, of the transmitted data in order to restore peripheral configuration after a power interruption. RESTOP is practically implemented and validated using three digitally interfaced peripherals, successfully restoring their configuration after power interruptions, imposing a maximum time overhead of 15% when configuring a peripheral. However, this represents an overhead of only 0.82% during complete execution of our typical sensing application, which is substantially lower than existing approaches.

Integrating renewable energy sources in the Portuguese power system

International Nuclear Information System (INIS)

Martins, Nuno; Cabral, Pedro; Azevedo, Helena

2012-01-01

The integration of large amounts of renewable energy is an important challenge for the future management of electric systems, since it affects the operation of the electric power system and the design of the transmission and distribution network infrastructure. This is specially due to the connection requirements of the renewable energy technologies, to the extension and adjustment of the grid infrastructure and to the identification of new solutions for operational reserve, in order to maintain the overall system flexibility and security. In this paper, the impact of high penetration of intermittent energy sources, expected in long term in the Portuguese Power System, is analysed and the operational reserve requirements to accomplish a reliable and reasonable electrical energy supply are identified. It was concluded that pumped storage power plants, special power plants with regulating capabilities, will have an important task to provide the operational reserve requirements of the Portuguese Power System. This technology assumes a fundamental role not only to ensure the adequate levels of security of supply but also to allow the maximum exploitation of the installed capacity in renewable energy sources. (authors)

Surplus from and storage of electricity generated by intermittent sources

Science.gov (United States)

Wagner, Friedrich

2016-12-01

Data from the German electricity system for the years 2010, 2012, 2013, and 2015 are used and scaled up to a 100% supply by intermittent renewable energy sources (iRES). In the average, 330GW wind and PV power are required to meet this 100% target. A back-up system is necessary with the power of 89% of peak load. Surplus electricity accrues at high power levels. Curtailing surplus power to a large extent is found to be uneconomic. Demand-side management will suffer from the strong day-to-day variation of available surplus energy. A day storage is ineffective because of the day-night correlation of surplus power during winter. A seasonal storage loses its character when transformation losses are considered because it can contribute only after periods with excessive surplus production. The option of an oversized iRES system to feed the storage is also not effective because, in this case, energy can be taken directly from the large iRES supply, making storage superfluous. The capacities to be installed stress the difficulty to base heat supply and mobility also on iRES generated electricity in the future. As the German energy transition replaces one CO2-free electricity supply system by another one, no major reduction in CO2 emission can be expected till 2022, when the last nuclear reactor will be switched off. By 2022, an extremely oversized power supply system has to be created, which can be expected to continue running down spot-market electricity prices. The continuation of the economic response -to replace expensive gas fuel by cheap lignite- causes an overall increase in CO2 emission. The German GHG emission targets for 2020 and beyond are therefore in jeopardy.

The future value of electrical energy storage in the UK with generator intermittency

Energy Technology Data Exchange (ETDEWEB)

NONE

2004-07-01

The intermittent nature of renewable energy sources increases the need for storage of electric power - the need is greatest in the case of wind power. This study looked at the potential value of power storage as a means of coping with variable power demand which, in the case of wind power, is itself intermittent. The benefits of using storage for part of the reserve needs compared with the reserve in the form of part-loaded conventional forms of generation was a feature of the study. The benefits were assessed in terms of (a) savings in fuel costs associated with balancing the systems; (b) carbon dioxide emissions, and (c) the additional amount of wind energy that can be absorbed. The work was conducted as part of the a UK DTI programme on New and Renewable Energy Sources.

The future value of electrical energy storage in the UK with generator intermittency

International Nuclear Information System (INIS)

2004-01-01

The intermittent nature of renewable energy sources increases the need for storage of electric power - the need is greatest in the case of wind power. This study looked at the potential value of power storage as a means of coping with variable power demand which, in the case of wind power, is itself intermittent. The benefits of using storage for part of the reserve needs compared with the reserve in the form of part-loaded conventional forms of generation was a feature of the study. The benefits were assessed in terms of (a) savings in fuel costs associated with balancing the systems; (b) carbon dioxide emissions, and (c) the additional amount of wind energy that can be absorbed. The work was conducted as part of the a UK DTI programme on New and Renewable Energy Sources

Discovery of burst oscillations in the intermittent accretion-powered millisecond pulsar HETE J1900.1-2455

NARCIS (Netherlands)

Watts, A.L.; Altamirano, D.; Linares, M.; Patruno, A.; Casella, P.; Cavecchi, Y.; Degenaar, N.; Rea, N.; Soleri, P.; van der Klis, M.; Wijnands, R.

2009-01-01

We report the discovery of burst oscillations from the intermittent accretion-powered millisecond pulsar (AMP) HETE J1900.1-2455, with a frequency ~1 Hz below the known spin frequency. The burst oscillation properties are far more similar to those of the non-AMPs and Aql X-1 (an intermittent AMP

Can renewable energy sources be financed through competitive power markets in the long run?; Koennen sich erneuerbare Energien langfristig auf wettbewerblich organisierten Strommaerkten finanzieren?

Energy Technology Data Exchange (ETDEWEB)

Kopp, Oliver; Essler-Frey, Anke; Engelhorn, Thorsten [MVV Energie AG, Mannheim (Germany)

2012-12-15

In this paper we address the issue of whether renewable energy sources can be integrated into power markets if the use of renewable energies is extended at the desired speed. Market integration means that renewable energy sources have to cover their full costs from revenues on competitive markets. In the first part of this paper, we evaluate the long-term revenues of intermittent renewable energy sources using a high resolution power market model. Considering the renewable targets of the German lead study of 2010, we show that due to the merit order effect, intermittent renewable energy sources, such as wind power and photovoltaic, cannot be financed through power markets alone, even if their full costs fall below those of conventional power plants. This is also true for scenarios with high CO{sub 2}-prices and increasing spot market prices. In the second part of this paper, we discuss whether in the long run additional instruments such as green certificates or capacity markets would allow for a more competitive financing of renewable energy sources. Center stage in the discussion is the question under which circumstances these instruments increase competitive pricing and decentralised market decisions. (orig.)

Electric Vehicles Integration in the Electric Power System with Intermittent Energy Sources - The Charge/Discharge infrastructure

DEFF Research Database (Denmark)

Marra, Francesco

The replacement of conventional fuelled vehicles with electric vehicles (EVs) is going to increase in the coming years, following the trend seen for renewable energy sources (RES), as photovoltaic (PV) and wind power. In this scenario, the electric power systems in Europe are going to accommodate...... increased levels of non-dispatchable and fluctuating energy sources, as well as additional power demand due to EV charging. If the charging of EVs can be intelligently managed, several advantages can be offered to the power system. How useful coordinated EV charging can be, in combination with RES...... and the power levels needed. Furthermore, during EV coordination, a number of nonlinearities and battery ageing issues should be taken into account, to ensure a correct EV coordination and to preserve the EV battery lifetime. The third part of this research exploits the use of EV load coordination as an energy...

Method for assessing the probability of accumulated doses from an intermittent source using the convolution technique

International Nuclear Information System (INIS)

Coleman, J.H.

1980-10-01

A technique is discussed for computing the probability distribution of the accumulated dose received by an arbitrary receptor resulting from several single releases from an intermittent source. The probability density of the accumulated dose is the convolution of the probability densities of doses from the intermittent releases. Emissions are not assumed to be constant over the brief release period. The fast fourier transform is used in the calculation of the convolution

Measuring power output intermittency and unsteady loading in a micro wind farm model

OpenAIRE

Bossuyt, Juliaan; Howland, Michael; Meneveau, Charles; Meyers, Johan

2016-01-01

In this study porous disc models are used as a turbine model for a wind-tunnel wind farm experiment, allowing the measurement of the power output, thrust force and spatially averaged incoming velocity for every turbine. The model's capabilities for studying the unsteady turbine loading, wind farm power output intermittency and spatio temporal correlations between wind turbines are demonstrated on an aligned wind farm, consisting of 100 wind turbine models.

Intermittency in branching models

International Nuclear Information System (INIS)

Chiu, C.B.; Texas Univ., Austin; Hwa, R.C.; Oregon Univ., Eugene

1990-01-01

The intermittency properties of three branching models have been investigated. The factorial moments show power-law behavior as function of small rapidity width. The slopes and energy dependences reveal different characteristics of the models. The gluon model has the weakest intermittency. (orig.)

Modeling and sizing a Storage System coupled with intermittent renewable power generation

International Nuclear Information System (INIS)

Bridier, Laurent

2016-01-01

This thesis aims at presenting an optimal management and sizing of an Energy Storage System (ESS) paired up with Intermittent Renewable Energy Sources (IReN). Firstly, we developed a technical-economic model of the system which is associated with three typical scenarios of utility grid power supply: hourly smoothing based on a one-day-ahead forecast (S1), guaranteed power supply (S2) and combined scenarios (S3). This model takes the form of a large-scale non-linear optimization program. Secondly, four heuristic strategies are assessed and lead to an optimized management of the power output with storage according to the reliability, productivity, efficiency and profitability criteria. This ESS optimized management is called 'Adaptive Storage Operation' (ASO). When compared to a mixed integer linear program (MILP), this optimized operation that is practicable under operational conditions gives rapidly near-optimal results. Finally, we use the ASO in ESS optimal sizing for each renewable energy: wind, wave and solar (PV). We determine the minimal sizing that complies with each scenario, by inferring the failure rate, the viable feed-in tariff of the energy, and the corresponding compliant, lost or missing energies. We also perform sensitivity analysis which highlights the importance of the ESS efficiency and of the forecasting accuracy and the strong influence of the hybridization of renewables on ESS technical-economic sizing. (author) [fr

Stochastic reactive power dispatch in hybrid power system with intermittent wind power generation

International Nuclear Information System (INIS)

Taghavi, Reza; Seifi, Ali Reza; Samet, Haidar

2015-01-01

Environmental concerns besides fuel costs are the predominant reasons for unprecedented escalating integration of wind turbine on power systems. Operation and planning of power systems are affected by this type of energy due to the intermittent nature of wind speed inputs with high uncertainty in the optimization output variables. Consequently, in order to model this high inherent uncertainty, a PRPO (probabilistic reactive power optimization) framework should be devised. Although MC (Monte-Carlo) techniques can solve the PRPO with high precision, PEMs (point estimate methods) can preserve the accuracy to attain reasonable results when diminishing the computational effort. Also, this paper introduces a methodology for optimally dispatching the reactive power in the transmission system, while minimizing the active power losses. The optimization problem is formulated as a LFP (linear fuzzy programing). The core of the problem lay on generation of 2m + 1 point estimates for solving PRPO, where n is the number of input stochastic variables. The proposed methodology is investigated using the IEEE-14 bus test system equipped with HVDC (high voltage direct current), UPFC (unified power flow controller) and DFIG (doubly fed induction generator) devices. The accuracy of the method is demonstrated in the case study. - Highlights: • This paper uses stochastic loads in optimization process. • AC–DC load flow is modified to use some advantages of DC part in optimization process. • UPFC and DFIG are simulated in a way that could be effective in optimization process. • Fuzzy set has been used as an uncertainty analysis tool in the optimization

Wide-Area Energy Storage and Management System to Balance Intermittent Resources in the Bonneville Power Administration and California ISO Control Areas

DEFF Research Database (Denmark)

Makarov, Yuri V.; Yang, Bo; DeSteese, John G.

2009-01-01

This paper addresses the issue of mitigating additional intermittency and fast ramps that are expected to occur at high penetration levels of intermittent resources, including wind generation resources, in the Bonneville Power Administration (BPA) and the California Independent System Operator...

Stream Tracker: Crowd sourcing and remote sensing to monitor stream flow intermittence

Science.gov (United States)

Puntenney, K.; Kampf, S. K.; Newman, G.; Lefsky, M. A.; Weber, R.; Gerlich, J.

2017-12-01

Streams that do not flow continuously in time and space support diverse aquatic life and can be critical contributors to downstream water supply. However, these intermittent streams are rarely monitored and poorly mapped. Stream Tracker is a community powered stream monitoring project that pairs citizen contributed observations of streamflow presence or absence with a network of streamflow sensors and remotely sensed data from satellites to track when and where water is flowing in intermittent stream channels. Citizens can visit sites on roads and trails to track flow and contribute their observations to the project site hosted by CitSci.org. Data can be entered using either a mobile application with offline capabilities or an online data entry portal. The sensor network provides a consistent record of streamflow and flow presence/absence across a range of elevations and drainage areas. Capacitance, resistance, and laser sensors have been deployed to determine the most reliable, low cost sensor that could be mass distributed to track streamflow intermittence over a larger number of sites. Streamflow presence or absence observations from the citizen and sensor networks are then compared to satellite imagery to improve flow detection algorithms using remotely sensed data from Landsat. In the first two months of this project, 1,287 observations have been made at 241 sites by 24 project members across northern and western Colorado.

Controllable and affordable utility-scale electricity from intermittent wind resources and compressed air energy storage (CAES)

International Nuclear Information System (INIS)

Cavallo, Alfred

2007-01-01

World wind energy resources are substantial, and in many areas, such as the US and northern Europe, could in theory supply all of the electricity demand. However, the remote or challenging location (i.e. offshore) and especially the intermittent character of the wind resources present formidable barriers to utilization on the scale required by a modern industrial economy. All of these technical challenges can be overcome. Long distance transmission is well understood, while offshore wind technology is being developed rapidly. Intermittent wind power can be transformed to a controllable power source with hybrid wind/compressed air energy storage (CAES) systems. The cost of electricity from such hybrid systems (including transmission) is affordable, and comparable to what users in some modern industrial economies already pay for electricity. This approach to intermittent energy integration has many advantages compared to the current strategy of forcing utilities to cope with supply uncertainty and transmission costs. Above all, it places intermittent wind on an equal technical footing with every other generation technology, including nuclear power, its most important long-term competitor

Energy storage in future power systems

DEFF Research Database (Denmark)

Rasmussen, Claus Nygaard; Østergaard, Jacob; Divya, K. C.

2011-01-01

Most sources of renewable power are characterised by uncontrollable and chaotic variations in power output. We here look at how energy storage may benefit renewable power generation by making it available in periods with little or no intermittent generation and thereby prevent additional conventi......Most sources of renewable power are characterised by uncontrollable and chaotic variations in power output. We here look at how energy storage may benefit renewable power generation by making it available in periods with little or no intermittent generation and thereby prevent additional...... conventional generation form being used. In addition to this, one of the strongest concerns in relation to renewable power is the instability in the electric power system that it may introduce as a result of large and relatively fast power fluctuations. An additional benefit of energy storage is therefore its...

Forces and energetics of intermittent swimming

Science.gov (United States)

Floryan, Daniel; Van Buren, Tyler; Smits, Alexander J.

2017-08-01

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry (PIV) flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

Integrating intermittent energy sources in liberalized electricity markets: from technical costs to economic penalties as a result of market rules

International Nuclear Information System (INIS)

Menanteau, Ph.; Finon, D.; Lamy, M.L.

2003-06-01

With the aim of preventing climatic change and ensuring the security of energy supplies, the recent European Directive on renewable energy production sources is aimed at bringing about a very substantial increase in electricity production from renewable sources in Europe by the 2010 horizon. Generally speaking, production of electricity from renewable sources will be assured by biomass and wind, and to a lesser extent by micro hydro, technologies whose characteristics are very different from the point of view of their integration into the electricity system. Their inclusion in the electricity systems will cause problems because of the intermittent nature of the production, a factor that does not enter into the paradigms of producers, system operators or regulators. The problems raised by the integration of intermittent production are technical in nature (risk of non-availability in peak periods, the need for additional reserves) and will incur adjustment costs, but the way in which the electricity markets function will impose economic penalties generally more substantial than the added technical costs. In this paper are examined in succession: (i) the additional costs raised by intermittence; (ii) the economic penalties imposed by the operating rules of de-regulated electricity markets with electricity production from renewable sources included, with particular reference to the case of the British and Nordic markets; and (iii) an analysis of the options that could limit the gap between the additional cost of intermittent production for the system and the adjustment surcharges imposed by the electricity markets, with the aim of reducing the tension between the deregulation of the electricity market and promoting the development of renewable energy sources. (A.L.B.)

Reducing the market impact of large shares of intermittent energy in Denmark

DEFF Research Database (Denmark)

Jacobsen, Henrik; Zvingilaite, Erika

2010-01-01

The increasing prevalence of renewable and intermittent energy sources in the electricity system is creating new challenges for the interaction of the system. In Denmark, high renewable shares have been achieved without great difficulty, mainly due to the flexibility of the nearby Nordic hydro......-power dominated system. Further increases in the share of renewable energy sources require that additional options are considered to facilitate integration with the lowest possible cost. With large shares of intermittent energy, the impact can be observed on wholesale prices, giving both lower prices and higher...... and the attractiveness of additional interconnection capacity. This paper also analyses options for increasing the flexibility of heat generation involving large and decentralized CHP plants and heat generation based on electricity. The incentives that the market provides for shifting demand and using electricity...

Analysis of Pumped Storage Plants (PSP) viability associated with other types of intermittent renewable energy

International Nuclear Information System (INIS)

Andrade, J G P; Barbosa, P S F; Luvizotto, E Jr; Zuculin, S; Pinto, Marrc; Filho, G L Tiago

2014-01-01

The energy generated by wind or solar photovoltaic (PV system) can be used by PSP to accumulate water in the upper reservoir, in the form of potential energy to be used later, during periods of high energy demand. This procedure offers the advantage of enabling the use of intermittent renewable energy source in times of growing needs of the electric power supply. The location of the PSP, the environmental aspects involved, their possible use for various purposes (stability of the power system at peak times, associate the turbine water for public supply purposes, among others) and the discussion of regulatory issues needs to be debated in the current context, where environmental issues require reliable sources of power generation and demand shows strong growth rates. A dynamic model is used to analyze the behavior of a PSP proposal for a site in Brazil, analyzing a complete cycle of its operation as a pump or turbine. The existing difficulties to use this proposal based on existing regulatory policies are also discussed, and a list of recommended adjustments is provided to allow the penetrations of PSP projects in the Brazilian institutional framework, coupled with other intermittent energy sources

Cosmic Rays in Intermittent Magnetic Fields

International Nuclear Information System (INIS)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S.; Snodin, Andrew P.

2017-01-01

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

Cosmic Rays in Intermittent Magnetic Fields

Energy Technology Data Exchange (ETDEWEB)

Shukurov, Anvar; Seta, Amit; Bushby, Paul J.; Wood, Toby S. [School of Mathematics and Statistics, Newcastle University, Newcastle Upon Tyne NE1 7RU (United Kingdom); Snodin, Andrew P., E-mail: a.seta1@ncl.ac.uk, E-mail: amitseta90@gmail.com [Department of Mathematics, Faculty of Applied Science, King Mongkut’s University of Technology North Bangkok, Bangkok 10800 (Thailand)

2017-04-10

The propagation of cosmic rays in turbulent magnetic fields is a diffusive process driven by the scattering of the charged particles by random magnetic fluctuations. Such fields are usually highly intermittent, consisting of intense magnetic filaments and ribbons surrounded by weaker, unstructured fluctuations. Studies of cosmic-ray propagation have largely overlooked intermittency, instead adopting Gaussian random magnetic fields. Using test particle simulations, we calculate cosmic-ray diffusivity in intermittent, dynamo-generated magnetic fields. The results are compared with those obtained from non-intermittent magnetic fields having identical power spectra. The presence of magnetic intermittency significantly enhances cosmic-ray diffusion over a wide range of particle energies. We demonstrate that the results can be interpreted in terms of a correlated random walk.

Demand response power system optimization in presence of renewable energy sources

Directory of Open Access Journals (Sweden)

Dumbrava Virgil

2017-07-01

Full Text Available This paper optimizes the price-based demand response of a large customer in a power system with stochastic production and classical fuel-supplied power plants. The implemented method of optimization, under uncertainty, is helpful to model both the utility functions for the consumers and their technical limitations. The consumers exposed to price-based demand can reduce their cost for electricity procurement by modifying their behavior, possibly shifting their consumption during the day to periods with low electricity prices. The demand is considered elastic to electricity price if the consumer is willing and capable to buy various amounts of energy at different price levels, the demand function being represented as purchasing bidding blocks. The demand response is seen also by the scientific literature as a possible source of the needed flexibility of modern power systems, while the flexibility of conventional generation technologies is restricted by technical constraints, such as ramp rates. This paper shows how wind power generation affects short term operation of the electricity system. Fluctuations in the amount of wind power fed into the grid require, without storage capacities, compensating changes in the output of flexible generators or in the consumers’ behavior. In the presented case study, we show the minimization of the overall costs in presence of stochastic wind power production. For highlighting the variability degree of production from renewable sources, four scenarios of production were formulated, with different probabilities of occurrence. The contribution brought by the paper is represented by the optimization model for demand-response of a large customer in a power system with fossil fueled generators and intermittent renewable energy sources. The consumer can reduce the power system costs by modifying his demand. The demand function is represented as purchasing bidding blocks for the possible price forecasted realizations

Wind Power - A Power Source Enabled by Power Electronics

DEFF Research Database (Denmark)

Blaabjerg, Frede; Chen, Zhe

2004-01-01

. The deregulation of energy has lowered the investment in bigger power plants, which means the need for new electrical power sources may be very high in the near future. Two major technologies will play important roles to solve the future problems. One is to change the electrical power production sources from......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. The production, distribution and the use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should be set up...... the conventional, fossil (and short term) based energy sources to renewable energy sources. The other is to use high efficient power electronics in power systems, power production and end-user application. This paper discuss the most emerging renewable energy source, wind energy, which by means of power...

Effects of wind intermittency on reduction of CO2 emissions: The case of the Spanish power system

International Nuclear Information System (INIS)

Gutiérrez-Martín, F.; Da Silva-Álvarez, R.A.; Montoro-Pintado, P.

2013-01-01

Renewable energy sources are believed to reduce drastically greenhouse gas emissions that would otherwise be generated from fossil fuels used to generate electricity. This implies that a unit of renewable energy will replace a unit of fossil-fuel, with its CO 2 emissions, on an equivalent basis – with no other effects on the grid. But, the fuel economy and emissions in the existing power systems are not proportional with the electricity production of intermittent sources due to cycling of the fossil-fuel plants that make up the balance of the grid (i.e. changing the power output makes thermal units to operate less efficiently). This study focuses in the interactions between wind generation and thermal plants cycling, by establishing the levels of extra fuel use caused by decreased efficiencies of fossil back-up for wind electricity in Spain. We analyze the production of all thermal plants in 2011, studying scenarios where wind penetration causes major deviations in programming and we define a procedure for quantifying CO 2 reductions using emission factors and efficiency curves from existing installations; the objective is to discuss the real contribution of renewable energy to the environmental targets: the results show that CO 2 reductions are still relevant at high wind penetration, whilst we also suggest alternatives to improve reliability of the power system. - Highlights: ► Comprehensive analysis of interactions of wind and fuel utilities in the power system. ► Fuel economy is not proportional with wind generation due to cycling of fossil plants. ► The results show that CO 2 reductions are still relevant even at high wind penetration. ► Alternatives to improve reliability of future power systems are also pointed out

Characterization of the Wind Power Resource in Europe and its Intermittency

Science.gov (United States)

Cosseron, Alexandra; Gunturu, Bhaskar; Schlosser, Adam

2013-04-01

Thanks to incentives from the European Union and recent events, the political situation in Europe has never been so favorable towards renewables. As one of the most mature technologies among them, wind power has been chosen to be assessed over Europe, with a special care given to intermittency and variability quantifications. The goal of this study is to construct and analyze the availability and variability of the wind potential across Europe using the methodology developed in Gunturu and Schlosser (2011). The Modern Era Retrospective-Analysis for Research and Applications (MERRA) boundary flux data was used to construct wind profiles at 50, 80, 100 and 120 meters height over a domain spreading from Iceland to the western end of Ukraine. Comparisons and contrasts with previous works have asserted the reliability of the data and computations used in the analysis. It must be emphasized though that the data set used in this study has a thirty-year length, a time resolution of an hour and is a reconstruction of the atmospheric state by assimilating observational data from different platforms into a global model. Various metrics, such as coefficients of variation, inter-quartile ranges, capacity factors and wind episode lengths, have been introduced to assess magnitude and variability of wind power. Then, unconventional variables have been designed to further study the availability and reliability of this resource. Thus, to study the correlation between wind episodes across Europe, parameters called antiCoincidence and antiNullCoincidence have been built. Pragmatically, the seven closest grid points in each direction at every grid point have been studied to assess whether they had wind when the considered point had or had not. The analysis of these variables leads to the conclusion that wind-proponents' favorite statement, "wind always blows somewhere", may not be so true. All of these metrics have finally allowed a better understanding of wind power features over

Unsteady propulsion by an intermittent swimming gait

Science.gov (United States)

Akoz, Emre; Moored, Keith W.

2018-01-01

Inviscid computational results are presented on a self-propelled swimmer modeled as a virtual body combined with a two-dimensional hydrofoil pitching intermittently about its leading edge. Lighthill (1971) originally proposed that this burst-and-coast behavior can save fish energy during swimming by taking advantage of the viscous Bone-Lighthill boundary layer thinning mechanism. Here, an additional inviscid Garrick mechanism is discovered that allows swimmers to control the ratio of their added mass thrust-producing forces to their circulatory drag-inducing forces by decreasing their duty cycle, DC, of locomotion. This mechanism can save intermittent swimmers as much as 60% of the energy it takes to swim continuously at the same speed. The inviscid energy savings are shown to increase with increasing amplitude of motion, increase with decreasing Lighthill number, Li, and switch to an energetic cost above continuous swimming for sufficiently low DC. Intermittent swimmers are observed to shed four vortices per cycle that form into groups that are self-similar with the DC. In addition, previous thrust and power scaling laws of continuous self-propelled swimming are further generalized to include intermittent swimming. The key is that by averaging the thrust and power coefficients over only the bursting period then the intermittent problem can be transformed into a continuous one. Furthermore, the intermittent thrust and power scaling relations are extended to predict the mean speed and cost of transport of swimmers. By tuning a few coefficients with a handful of simulations these self-propelled relations can become predictive. In the current study, the mean speed and cost of transport are predicted to within 3% and 18% of their full-scale values by using these relations.

Managing intermittent sources of electricity: the prospects opened by research

International Nuclear Information System (INIS)

Bigot, Bernard

2013-01-01

Beyond the difficult question of foreseeing the additional cost of placing one kWh of electricity on the grid - a cost that must be kept as low as possible to improve the technology for harnessing and converting energy - the growing share of electricity from renewable energy sources in national consumption (initially in replacement of fossil fuels) raises questions for research. How to limit the factors that make most of these forms of energy intermittent? One solution involves developing local or centralized storage capacities that are technically and economically efficient. Another proposal has to do with introducing information technology in electricity grids and electric appliances in order to reverse the currently prevailing rationale so that demand adjusts to supply, and not the reverse, in proportions that, though probably limited, are indispensable

Concept of large scale PV-WT-PSH energy sources coupled with the national power system

Directory of Open Access Journals (Sweden)

Jurasz Jakub

2017-01-01

Full Text Available Intermittent/non-dispatchable energy sources are characterized by a significant variation of their energy yield over time. In majority of cases their role in energy systems is marginalized. However, even in Poland which is strongly dedicated to its hard and brown coal fired power plants, the wind generation in terms of installed capacity starts to play a significant role. This paper briefly introduces a concept of wind (WT and solar (PV powered pumped storage hydroelectricity (PSH which seems to be a viable option for solving the problem of the variable nature of PV and WT generation. Additionally we summarize the results of our so far conducted research on the integration of variable renewable energy sources (VRES to the energy systems and present conclusions which strictly refer to the prospects of large scale PV-WT-PSH operating as a part of the polish energy system.

Intermittency '93

International Nuclear Information System (INIS)

Bialas, A.

1993-01-01

The existing data definitely indicate the existence of intermittency, i.e. of self similar structures in the systems of particles created in high-energy collisions. The effect seems universal: it was found in most of the processes investigated and its measures parameters depend only weakly (if at all) on the process in question. Strong HBT effect was found, suggesting that intermittency is related to space-time structure of the pion source rather than to detailed momentum structure of the production amplitudes. There are indications that this space time structure may be fractal, but more data is needed to establish this. The theoretical explanation remains obscure: it seems that both parton cascade and hadronization play an important role. Their interrelation, however, remains a mystery. 5 figs., 19 refs

Intermittency in the particle production and in the nuclear multifragmentation

International Nuclear Information System (INIS)

Bozek, P.; Ploszajczak, M.

1991-01-01

Intermittency is a manifestation of scale invariance and randomness in physical systems. Intermittency in relativistic heavy-ion collisions and, in particular, the projectile dependence, multiplicity dependence and source-size dependence are discussed in the frame of the model of spatio-temporal intermittency. Moreover, recent theoretical results in intermittency studies of the nuclear multifragmentation are presented. (author) 35 refs., 4 figs., 1 tab

Power source system for nuclear fusion

International Nuclear Information System (INIS)

Nakagawa, Satoshi.

1975-01-01

Object: When using an external system power source and an exclusive power source in a power source circuit for supplying power to the coils of a nuclear fusion apparatus, to minimize the capacity of the exclusive power source and provide an economical power source circuit construction. Structure: In the initial stage of the power supply, rectifying means provided in individual blocks are connected in parallel on the AC side, and power is supplied to the coils of the nuclear fusion apparatus from an external system power source with the exclusive power source held in the disconnected state. Further, at an instant when the limit of permissible input is reached, the afore-mentioned parallel circuit consisting of rectifying means is disconnected, while at the same time the exclusive power source is connected to the input side of the rectifying means provided in a block corresponding to the exclusive power source side, thereby supplying power to the coils of the nuclear fusion apparatus from both the external system power source and exclusive power source. (Kamimura, M.)

The 'Critical Power' Concept: Applications to Sports Performance with a Focus on Intermittent High-Intensity Exercise.

Science.gov (United States)

Jones, Andrew M; Vanhatalo, Anni

2017-03-01

The curvilinear relationship between power output and the time for which it can be sustained is a fundamental and well-known feature of high-intensity exercise performance. This relationship 'levels off' at a 'critical power' (CP) that separates power outputs that can be sustained with stable values of, for example, muscle phosphocreatine, blood lactate, and pulmonary oxygen uptake ([Formula: see text]), from power outputs where these variables change continuously with time until their respective minimum and maximum values are reached and exercise intolerance occurs. The amount of work that can be done during exercise above CP (the so-called W') is constant but may be utilized at different rates depending on the proximity of the exercise power output to CP. Traditionally, this two-parameter CP model has been employed to provide insights into physiological responses, fatigue mechanisms, and performance capacity during continuous constant power output exercise in discrete exercise intensity domains. However, many team sports (e.g., basketball, football, hockey, rugby) involve frequent changes in exercise intensity and, even in endurance sports (e.g., cycling, running), intensity may vary considerably with environmental/course conditions and pacing strategy. In recent years, the appeal of the CP concept has been broadened through its application to intermittent high-intensity exercise. With the assumptions that W' is utilized during work intervals above CP and reconstituted during recovery intervals below CP, it can be shown that performance during intermittent exercise is related to four factors: the intensity and duration of the work intervals and the intensity and duration of the recovery intervals. However, while the utilization of W' may be assumed to be linear, studies indicate that the reconstitution of W' may be curvilinear with kinetics that are highly variable between individuals. This has led to the development of a new CP model for intermittent exercise in

Renewable energies for power generation

International Nuclear Information System (INIS)

Freris, L.; Infield, D.

2009-01-01

Power generation from renewable energy sources is different from power generation from classical energies (nuclear, thermal..). Therefore, the integration into the grid of the electricity supplied by renewable sources requires a deep thinking. The reason is that these power sources are controlled by variable elements, like wind, water and sun, which condition production. This book deals with the following aspects in detail: characteristics of classical and intermittent generators; grid balancing between supply and demand; conversion methods of renewable energies into electricity; power systems; privatizing of power generation and birth of new markets, in particular the 'green' power market; development of renewable energies thanks to technical advances. It gives a comprehensive overview of the present day available renewable energy sources for power generation. (J.S.)

Comparison between Different Power Sources for Emergency Power Supply at Nuclear Power Plants

International Nuclear Information System (INIS)

Lenasson, Magnus

2015-01-01

Currently the Swedish nuclear power plants are using diesel generator sets and to some extent gas turbines as their emergency AC power sources and batteries as their emergency DC power sources. In the laws governing Swedish nuclear activity, no specific power sources are prescribed. On the other hand, diversification of safety functions should be considered, as well as simplicity and reliability in the safety systems. So far the choices of emergency power sources have been similar between different power plants, and therefore this project investigated a number of alternative power sources and if they are suitable for use as emergency power on nuclear power plants. The goals of the project were to: - Define the parameters that are essential for rending a power source suitable for use at a nuclear power plant. - Present the characteristics of a number of power sources regarding the defined parameters. - Compile the suitability of the different power sources. - Make implementation suggestions for the less conventional of the investigated power sources. (unconventional in the investigated application) 10 different power sources in total have been investigated and to various degrees deemed suitable Out of the 10 power sources, diesel generators, batteries and to some extent gas turbines are seen as conventional technology at the nuclear power plants. In relation to them the other power sources have been assessed regarding diversification gains, foremost with regards to external events. The power sources with the largest diversification gains are: Internal steam turbine, Hydro power, Thermoelectric generators. The work should first and foremost put focus on the fact that under the right circumstances there are power sources that can complement conventional power sources and yield substantial diversification gains. This paper is a shortened version of the report 'Comparison between different power sources for emergency power supply at nuclear power plants'. The

Power source facility

Energy Technology Data Exchange (ETDEWEB)

Yoshikawa, Kazuhiro; Kinoshita, Shoichiro

1998-09-29

The present invention concerns a power plant, in which power is supplied from an ordinary system battery to an ordinary DC bus system when all of the AC power sources should be lost and a generator is driven by a steam turbine. A generator is connected with an ordinary system battery charger by way of a channel. If all of power sources should be lost, the ordinary system battery charger is driven by using emergency steam turbine generator facilities, and reactor steams are supplied thereby enabling to supply power to the ordinary system DC bus system for a long period of time. (N.H.)

Optimal Integration of Intermittent Renewables: A System LCOE Stochastic Approach

Directory of Open Access Journals (Sweden)

Carlo Lucheroni

2018-03-01

Full Text Available We propose a system level approach to value the impact on costs of the integration of intermittent renewable generation in a power system, based on expected breakeven cost and breakeven cost risk. To do this, we carefully reconsider the definition of Levelized Cost of Electricity (LCOE when extended to non-dispatchable generation, by examining extra costs and gains originated by the costly management of random power injections. We are thus lead to define a ‘system LCOE’ as a system dependent LCOE that takes properly into account intermittent generation. In order to include breakeven cost risk we further extend this deterministic approach to a stochastic setting, by introducing a ‘stochastic system LCOE’. This extension allows us to discuss the optimal integration of intermittent renewables from a broad, system level point of view. This paper thus aims to provide power producers and policy makers with a new methodological scheme, still based on the LCOE but which updates this valuation technique to current energy system configurations characterized by a large share of non-dispatchable production. Quantifying and optimizing the impact of intermittent renewables integration on power system costs, risk and CO 2 emissions, the proposed methodology can be used as powerful tool of analysis for assessing environmental and energy policies.

Generation of intermittent gravitocapillary waves via parametric forcing

Science.gov (United States)

Castillo, Gustavo; Falcón, Claudio

2018-04-01

We report on the generation of an intermittent wave field driven by a horizontally moving wave maker interacting with Faraday waves. The spectrum of the local gravitocapillary surface wave fluctuations displays a power law in frequency for a wide range of forcing parameters. We compute the probability density function of the local surface height increments, which show that they change strongly across time scales. The structure functions of these increments are shown to display power laws as a function of the time lag, with exponents that are nonlinear functions of the order of the structure function. We argue that the origin of this scale-invariant intermittent spectrum is the Faraday wave pattern breakup due to its advection by the propagating gravity waves. Finally, some interpretations are proposed to explain the appearance of this intermittent spectrum.

Limits and Prospects of Renewable Energy Sources in Italy

International Nuclear Information System (INIS)

Coiante, D.

2008-01-01

The Italian energy balance for year 2005 is discussed with particular attention on renewable energy production. The potentials of renewable sources are evaluated in terms of energy density that can be obtained from occupied plant area. About 20000 km 2 of sunny barren lands are present in South of Italy, particularly suitable for photovoltaic plants and that corresponds to a potential production of 144 Mtep of primary energy. Therefore, in theory, the photovoltaic energy potential is comparable with energy balance. The grid connection limit due to intermittent power generation of photovoltaic and wind energy systems is considered in relation with the stability of grid power level. Assuming a 25% maximum grid penetration of intermittent power with respect to capacity of active thermoelectric generators, the renewable energy contribution amounts to about 2% of annual energy balance. In front of expectations for a larger contribution, the practical result is the renewable energy production of present systems is marginal, unsuitable for counteracting the global climate crisis. The conclusion is that, for exploiting the large renewable energy potential, is necessary to implement the plants with an energy storage system able to overcome the source intermittency. Without this improvement, the expectations on renewable energy sources could be disappointed. [it

Agent-based power sharing scheme for active hybrid power sources

Science.gov (United States)

Jiang, Zhenhua

The active hybridization technique provides an effective approach to combining the best properties of a heterogeneous set of power sources to achieve higher energy density, power density and fuel efficiency. Active hybrid power sources can be used to power hybrid electric vehicles with selected combinations of internal combustion engines, fuel cells, batteries, and/or supercapacitors. They can be deployed in all-electric ships to build a distributed electric power system. They can also be used in a bulk power system to construct an autonomous distributed energy system. An important aspect in designing an active hybrid power source is to find a suitable control strategy that can manage the active power sharing and take advantage of the inherent scalability and robustness benefits of the hybrid system. This paper presents an agent-based power sharing scheme for active hybrid power sources. To demonstrate the effectiveness of the proposed agent-based power sharing scheme, simulation studies are performed for a hybrid power source that can be used in a solar car as the main propulsion power module. Simulation results clearly indicate that the agent-based control framework is effective to coordinate the various energy sources and manage the power/voltage profiles.

Wind power - a power source now enabled by power electronics

DEFF Research Database (Denmark)

Blaabjerg, Frede; Iov, Florin

2007-01-01

energy at the end-user should be set up. Deregulation of energy has lowered the investment in larger power plants, which means the need for new electrical power sources may be increased in the near future. Two major technologies will play important roles to solve the future problems. One is to change......The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save...... the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. Another is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most emerging...

Radioisotope Power Sources

International Nuclear Information System (INIS)

Culwell, J. P.

1963-01-01

The radioisotope power programme of the US Atomic Energy Commission has brought forth a whole new technology of the use of radioisotopes as energy sources in electric power generators. Radioisotope power systems are particularly suited for remote applications where long-lived, compact, reliable power is needed. Able to perform satisfactorily under extreme environmental conditions of temperature, sunlight and electromagnetic radiations, these ''atomic batteries'' are attractive power sources for remote data collecting devices, monitoring systems, satellites and other space missions. Radioisotopes used as fuels generally are either alpha or beta emitters. Alpha emitters are the preferable fuels but are more expensive and less available than beta fuels and are generally reserved for space applications. Beta fuels separated from reactor fission wastes are being used exclusively in land and sea applications at the present. It can be expected, however, that beta emitters such as stiontium-90 eventually will be used in space. Development work is being carried out on generators which will use mixed fission products as fuel. This fuel will be less expensive than the pure radioisotopes since the costs of isotope separation and purification are eliminated. Prototype thermoelectric generators, fuelled with strontium-90 and caesium-137, are now in operation or being developed for use in weather stations, marine navigation aids and deep sea monitoring devices. A plutonium-238 thermoelectric generator is in orbit operating as electric power source in a US Navy TRANSIT satellite. Generators are under development for use on US National Aeronautics and Space Administration missions. The large quantities of radioactivity involved in radioisotope power sources require that special attention be given to safety aspects of the units. Rigid safety requirements have been established and extensive tests have been conducted to insure that these systems can be employed without creating undue

Rf power sources

International Nuclear Information System (INIS)

Allen, M.A.

1988-01-01

In this paper, the author reports on RF power sources for accelerator applications. The approach will be with particular customers in mind. These customers are high energy physicists who use accelerators as experimental tools in the study of the nucleus of the atom, and synchrotron light sources derived from electron or positron storage rings. The author pays close attention to electron- positron linear accelerators since the RF sources have always defined what is possible to achieve with these accelerators. Circular machines, cyclotrons, synchrotrons, etc. have usually not been limited by the RF power available and the machine builders have usually had their RF power source requirements met off the shelf. The main challenge for the RF scientist has been then in the areas of controls. An interesting example of this is in the Conceptual Design Report of the Superconducting Super Collider (SSC) where the RF system is described in six pages of text in a 700-page report. Also, the cost of that RF system is about one-third of a percent of the project's total cost. The RF system is well within the state of the art and no new power sources need to be developed. All the intellectual effort of the system designer would be devoted to the feedback systems necessary to stabilize beams during storage and acceleration, with the main engineering challenges (and costs) being in the superconducting magnet lattice

Sustainable integration of high levels of intermittent generation

International Nuclear Information System (INIS)

Pereira, R.; Cabral, P.

2005-01-01

The sustainable development of electric power systems rely on three main drivers: the security of supply, the competitiveness and the protection of the environment. For this purpose the promotion of endogenous energy sources, mainly the renewable ones, should be underlined. Still, most of renewable energy sources raise very sensitive issues concerning the security of supply, due to its randomness and unpredictability. The wind power, currently in its fast growing development, plays a relevant role on this matter. From the demand-side perspective, there is also a lot to do regarding the promotion of more efficient use of energy as well as mechanisms that contribute to security of supply. This paper aims to present guidelines for the selection of the most adequate solutions regarding: sustainable evolution of renewable generation technologies, based on the most meritorious resources under economic and security of supply assessments; complementary energy storage systems that allow the integration of intermittent generation ensuring adequate security of supply levels; and sustainable evolution of demand, based on DSM measures selected from different available alternatives. (author)

Offering model for a virtual power plant based on stochastic programming

DEFF Research Database (Denmark)

PandŽić, Hrvoje; Morales González, Juan Miguel; Conejo, Antonio J.

2013-01-01

A virtual power plant aggregates various local production/consumption units that act in the market as a single entity. This paper considers a virtual power plant consisting of an intermittent source, a storage facility, and a dispatchable power plant. The virtual power plant sells and purchases e...

Boosting the adoption and the reliability of renewable energy sources: Mitigating the large-scale wind power intermittency through vehicle to grid technology

International Nuclear Information System (INIS)

Zhao, Yang; Noori, Mehdi; Tatari, Omer

2017-01-01

The integration of wind energy in the electricity sector and the adoption of electric vehicles in the transportation sector both have the potential to significantly reduce greenhouse gas emissions individually as well as in tandem with Vehicle-to-Grid technology. This study aims to evaluate the greenhouse gas emission savings of mitigating intermittency resulting from the introduction of wind power through Vehicle-to-Grid technologies, as well as the extent to which the marginal electricity consumption from charging an electric vehicle fleet may weaken this overall environmental benefit. To this end, the comparisons are conducted in seven independent system operator regions. The results indicate that, in most cases, the emission savings of a combination of wind power and Vehicle-to-Grid technology outweighs the additional emissions from marginal electricity generation for electric vehicles. In addition, the fluctuations in newly-integrated wind power could be balanced in the future using EVs and V2G technology, provided that a moderate portion of EV owners is willing to provide V2G services. On the other hand, such a combination is not favorable if the Vehicle-to-Grid service participation rate is less than 5% of all electric vehicle owners within a particular region. - Highlights: • The environmental benefit of vehicle to grid systems as grid stabilizer is analyzed. • Emission savings of vehicle to grid and impacts of electric vehicles are compared. • Seven independent system operator regions are studied. • Uncertainty and sensitivity analysis are performed through a Monte Carlo Simulation.

Compact reactor/ORC power source

International Nuclear Information System (INIS)

Meier, K.L.; Kirchner, W.L.; Willcutt, G.J.

1986-01-01

A compact power source that combines an organic Rankine Cycle (ORC) electric generator with a nuclear reactor heat source is being designed and fabricated. Incorporating existing ORC technology with proven reactor technology, the compact reactor/ORC power source offers high reliability while minimizing the need for component development. Thermal power at 125 kWt is removed from the coated particle fueled, graphite moderated reactor by heat pipes operating at 500 0 C. Outside the reactor vessel and connected to the heat pipes are vaporizers in which the toluene ORC working fluid is heated to 370 0 C. In the turbine-alternator-pump (TAP) combined-rotating unit, the thermal energy of the toluene is converted to 25 kWe of electric power. Lumped parameter systems analyses combined with a finite element thermal analysis have aided in the power source design. The analyses have provided assurance of reliable multiyear normal operation as well as full power operation with upset conditions, such as failed heat pipes and inoperative ORC vaporizers. Because of inherent high reliability, long life, and insensitivity to upset conditions, this power source is especially suited for use in remote, inaccessible locations where fuel delivery and maintenance costs are high. 10 refs

Backup power sources for DOE facilities

Energy Technology Data Exchange (ETDEWEB)

1994-09-01

This standard establishes fundamental requirements and guidance for backup power sources at DOE facilities. Purpose is to document good engineering practices for installation, testing, and maintenance of these backup power sources, which also covers emergency power sources. Examples are those which supply power to nuclear safety systems, radiation monitors and alarms, fire protection systems, security systems, and emergency lighting.

Photoluminescence intermittency of semiconductor quantum dots in dielectric environments

Energy Technology Data Exchange (ETDEWEB)

Isaac, A.

2006-08-11

The experimental studies presented in this thesis deal with the photoluminescence intermittency of semiconductor quantum dots in different dielectric environments. Detailed analysis of intermittency statistics from single capped CdSe/ZnS, uncapped CdSe and water dispersed CdSe/ZnS QDs in different matrices provide experimental evidence for the model of photoionization with a charge ejected into the surrounding matrix as the source of PL intermittency phenomenon. We propose a self-trapping model to explain the increase of dark state lifetimes with the dielectric constant of the matrix. (orig.)

Clan structure as a source of intermittency in high energy multihadron production

International Nuclear Information System (INIS)

Hove, L. van

1989-01-01

Recently the systematic study of charged hadron multiplicity distributions in high energy hadronic and leptonic collisions has revealed the general occurrence of negative binomial regularities in symmetric CM rapidity windows and of intermittency in very small windows in the central region. The negative binomial regularities imply a particular form of clustering called clan structure, which embodies all Mueller multiparticle correlations. We show that this clan structure leads to intermittency when the simplest assumptions are made on the behaviour of the clans in very small windows. (orig.)

Spark-safe power source

Energy Technology Data Exchange (ETDEWEB)

Mester, I M; Konushkin, N A; Nevozinskiy, A K; Rubinshteyn, B Sh; Serov, V I; Vasnev, M A

1981-01-01

A shortcoming of the known power sources is their low reliability. The purpose of the invention is to improve the reliability of the device. This is achieved because the spark-safe power source is equipped with a by-passing transistor and potentiometer, and also a generator of control interruptions in the circuit, an I-element, first separating transformer, control block, second separating transformer whose secondary winding has a relay winding whose contacts are connected to the load circuit are connected in series. The generator of control separations of the circuit is connected to the base of the by-passing transistor and to the power source outlet, the potentiometer is connected in series to the main thyristor. The middle point of the potentiometer is connected to the second inlet of the I-element.

Coexistence of intermittencies in the neuronal network of the epileptic brain.

Science.gov (United States)

Koronovskii, Alexey A; Hramov, Alexander E; Grubov, Vadim V; Moskalenko, Olga I; Sitnikova, Evgenia; Pavlov, Alexey N

2016-03-01

Intermittent behavior occurs widely in nature. At present, several types of intermittencies are known and well-studied. However, consideration of intermittency has usually been limited to the analysis of cases when only one certain type of intermittency takes place. In this paper, we report on the temporal behavior of the complex neuronal network in the epileptic brain, when two types of intermittent behavior coexist and alternate with each other. We prove the presence of this phenomenon in physiological experiments with WAG/Rij rats being the model living system of absence epilepsy. In our paper, the deduced theoretical law for distributions of the lengths of laminar phases prescribing the power law with a degree of -2 agrees well with the experimental neurophysiological data.

Impedance source power electronic converters

CERN Document Server

Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

2016-01-01

Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

Factors Relevant to Utility Integration of Intermittent Renewable Technologies

Energy Technology Data Exchange (ETDEWEB)

Wan, Y.; Parsons, B.

1993-08-24

This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among fmdings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface, (2) cost penalties have not occurred at low to moderate penetration levels (and high levels am feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also indentified.

Factors relevant to utility integration of intermittent renewable technologies

Energy Technology Data Exchange (ETDEWEB)

Wan, Yih-huei; Parsons, B.K.

1993-08-01

This study assesses factors that utilities must address when they integrate intermittent renewable technologies into their power-supply systems; it also reviews the literature in this area and has a bibliography containing more than 350 listings. Three topics are covered: (1) interface (hardware and design-related interconnection), (2) operability/stability, and (3) planning. This study finds that several commonly held perceptions regarding integration of intermittent renewable energy technologies are not valid. Among findings of the study are the following: (1) hardware and system design advances have eliminated most concerns about interface; (2) cost penalties have not occurred at low to moderate penetration levels (and high levels are feasible); and (3) intermittent renewable energy technologies can have capacity values. Obstacles still interfering with intermittent renewable technologies are also identified.

Radioisotope Power Sources for MEMS Devices,

International Nuclear Information System (INIS)

Blanchard, J.P.

2001-01-01

Microelectromechanical systems (MEMS) comprise a rapidly expanding research field with potential applications varying from sensors in airbags to more recent optical applications. Depending on the application, these devices often require an on-board power source for remote operation, especially in cases requiring operation for an extended period of time. Previously suggested power sources include fossil fuels and solar energy, but nuclear power sources may provide significant advantages for certain applications. Hence, the objective of this study is to establish the viability of using radioisotopes to power realistic MEMS devices. A junction-type battery was constructed using silicon and a 63 Ni liquid source. A source volume containing 64 microCi provided a power of ∼0.07 nW. A more novel application of nuclear sources for MEMS applications involves the creation of a resonator that is driven by charge collection in a cantilever beam. Preliminary results have established the feasibility of this concept, and future work will optimize the design for various applications

Unified System-Level Modeling of Intermittent Renewable Energy Sources and Energy Storage for Power System Operation

DEFF Research Database (Denmark)

Heussen, Kai; Koch, Stephan; Ulbig, Andreas

2011-01-01

The system-level consideration of inter- mittent renewable energy sources and small-scale en- ergy storage in power systems remains a challenge as either type is incompatible with traditional operation concepts. Non-controllability and energy-constraints are still considered contingent cases...... in market-based operation. The design of operation strategies for up to 100 % renewable energy systems requires an explicit consideration of non-dispatchable generation and stor- age capacities, as well as the evaluation of operational performance in terms of energy eciency, reliability, environmental...... impact and cost. By abstracting from technology-dependent and physical unit properties, the modeling framework presented and extended in this pa- per allows the modeling of a technologically diverse unit portfolio with a unied approach, whilst establishing the feasibility of energy-storage consideration...

Solar cell power source system

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Yoichi; Toma, Kunio; Fukuwa, Shinji

1988-05-14

This invention aims to supply a power source system with stable power output by reducing the power loss due to switching in the voltage stabilization even when the power source is a solar cell with frequent voltage variation. For this purpose, in a solar cell power source system consisting of a solar cell, a storage battery, a switching regulator placed between the storage cell and the load, and a load, arrangement was made that, by judging the input voltage from the storage battery, switch-acting the transistor of the switching regulator, if the input voltage is higher than the specified voltage; is the input voltage is lower than the specified voltage, the transistor is put in a full-on state. By this, the supply voltage can be stabilized even when the voltage fluctuates, and system gets more efficient as the switching loss decreases in the voltage stabilizing means. (1 fig)

Rf power sources

International Nuclear Information System (INIS)

Allen, M.A.

1988-05-01

This paper covers RF power sources for accelerator applications. The approach has been with particular customers in mind. These customers are high energy physicists who use accelerators as experimental tools in the study of the nucleus of the atom, and synchrotron light sources derived from electron or positron storage rings. This paper is confined to electron-positron linear accelerators since the RF sources have always defined what is possible to achieve with these accelerators. 11 refs., 13 figs

Solar Power Sources

DEFF Research Database (Denmark)

Kim, Katherine A.; Mentesidi, Konstantina; Yang, Yongheng

2017-01-01

a significant change. Beyond this energy transition, the still declining cost of the solar technology has become an important driving force for more solar-powered systems. However, high penetration of solar-powered systems also brings technical challenges to the entire energy systems. In order to fully address......Solar power is highly abundant, relatively reliable, and not limited to a geographic region, making it one of the most important renewable energy sources. Catering for a clean and green energy system, solar energy will be an active player in the future mixed power grid that is also undergoing...... those issues, the technological properties of solar power should be investigated. Thus, the basics of solar power technology will be introduced and discussed in this chapter....

High average power supercontinuum sources

Indian Academy of Sciences (India)

The physical mechanisms and basic experimental techniques for the creation of high average spectral power supercontinuum sources is briefly reviewed. We focus on the use of high-power ytterbium-doped fibre lasers as pump sources, and the use of highly nonlinear photonic crystal fibres as the nonlinear medium.

Thulium heat sources for space power applications

International Nuclear Information System (INIS)

Alderman, C.J.

1992-05-01

Reliable power supplies for use in transportation and remote systems will be an important part of space exploration terrestrial activities. A potential power source is available in the rare earth metal, thulium. Fuel sources can be produced by activating Tm-169 targets in the space station reactor. The resulting Tm-170 heat sources can be used in thermoelectric generators to power instrumentation and telecommunications located at remote sites such as weather stations. As the heat source in a dynamic Sterling or Brayton cycle system, the heat source can provide a lightweight power source for rovers or other terrestrial transportation systems

Impacts of intermittent renewable generation on electricity system costs

International Nuclear Information System (INIS)

Batalla-Bejerano, Joan; Trujillo-Baute, Elisa

2016-01-01

A successful deployment of power generation coming from variable renewable sources, such as wind and solar photovoltaic, strongly depends on the economic cost of system integration. This paper, in seeking to look beyond the impact of renewable generation on the evolution of the total economic costs associated with the operation of the electricity system, aims to estimate the sensitivity of balancing market requirements and costs to the variable and non-fully predictable nature of intermittent renewable generation. The estimations reported in this paper for the Spanish electricity system stress the importance of both attributes as well as power system flexibility when accounting for the cost of balancing services. - Highlights: •A successful deployment of VRES-E strongly depends on the economic cost of its integration. •We estimate the sensitivity of balancing market requirements and costs to VRES-E. •Integration costs depend on variability, predictability and system flexibility.

Mesoscopic fluctuations and intermittency in aging dynamics

Science.gov (United States)

Sibani, P.

2006-01-01

Mesoscopic aging systems are characterized by large intermittent noise fluctuations. In a record dynamics scenario (Sibani P. and Dall J., Europhys. Lett., 64 (2003) 8) these events, quakes, are treated as a Poisson process with average αln (1 + t/tw), where t is the observation time, tw is the age and α is a parameter. Assuming for simplicity that quakes constitute the only source of de-correlation, we present a model for the probability density function (PDF) of the configuration autocorrelation function. Beside α, the model has the average quake size 1/q as a parameter. The model autocorrelation PDF has a Gumbel-like shape, which approaches a Gaussian for large t/tw and becomes sharply peaked in the thermodynamic limit. Its average and variance, which are given analytically, depend on t/tw as a power law and a power law with a logarithmic correction, respectively. Most predictions are in good agreement with data from the literature and with the simulations of the Edwards-Anderson spin-glass carried out as a test.

A compact reactor/ORC power source

International Nuclear Information System (INIS)

Meier, K.L.; Kirchner, W.L.; Willcutt, G.J.

1986-01-01

A compact power source that combines an organic Rankine cycle (ORC) electric generator with a nuclear reactor heat source is being designed and fabricated. Incorporating existing ORC technology with proven reactor technology, the compact reactor/ORC power source offers high reliability while minimizing the need for componenet development. Thermal power at 125 kWt is removed from the coated particle fueled, graphite moderated reactor by heat pipes operating at 500 0 C. Outside the reactor vessel and connected to the heat pipes are vaporizers in which the toluene ORC working fluid is heated to 370 0 C. In the turbine-alternator-pump (TAP) combined-rotating unit, the thermal energy of the toluene is converted to 25 kWe of electric power. Lumped parameter systems analyses combined with a finite element thermal analyses combined with a finite element thermal analysis have aided in the power source design. The analysis have provided assurance of reliable multiyear normal operation as well as full power operation with upset conditions, such as failed heat pipes and inoperative ORC vaporizers. Because of inherent high reliability, long life, and insensitivity to upset conditions, this power source is especially suited for use in remote, inaccessible locations where fuel delivery and maintenance costs are high

Optimization of continuous and intermittent microwave extraction of pectin from banana peels.

Science.gov (United States)

Swamy, Gabriela John; Muthukumarappan, Kasiviswanathan

2017-04-01

Continuous and intermittent microwave-assisted extractions were used to extract pectin from banana peels. Extraction parameters which were employed in the continuous process were microwave power (300-900W), time (100-300s), pH (1-3) and in the intermittent process were microwave power (300-900W), pulse ratio (0.5-1), pH (1-3). The independent factors were optimized with the Box-Behnken response surface design (BBD) (three factor three level) with the desirability function methodology. Results indicate that the independent factors have substantial effect on the pectin yield. Optimized solutions for highest pectin yield (2.18%) from banana peels were obtained with microwave power of 900W, time 100s and pH 3.00 in the continuous method while the intermittent process yielded the highest pectin content (2.58%) at microwave power of 900W, pulse ratio of 0.5 and pH of 3.00. The optimized conditions were validated and close agreement was observed with the validation experiment and predicted value. Copyright © 2016 Elsevier Ltd. All rights reserved.

Tritium power source for long-lived sensors

Science.gov (United States)

Litz, M. S.; Katsis, D. C.; Russo, J. A.; Carroll, J. J.

2014-06-01

A tritium-based indirect converting photovoltaic (PV) power source has been designed and prototyped as a long-lived (~15 years) power source for sensor networks. Tritium is a biologically benign beta emitter and low-cost isotope acquired from commercial vendors for this purpose. The power source combines tritium encapsulated with a radioluminescent phosphor coupled to a commercial PV cell. The tritium, phosphor, and PV components are packaged inside a BA5590-style military-model enclosure. The package has been approved by the nuclear regulatory commission (NRC) for use by DOD. The power source is designed to produce 100μW electrical power for an unattended radiation sensor (scintillator and avalanche photodiode) that can detect a 20 μCi source of 137Cs at three meters. This beta emitting indirect photon conversion design is presented as step towards the development of practical, logistically acceptable, lowcost long-lived compact power sources for unattended sensor applications in battlefield awareness and environmental detection.

Special Application Thermoelectric Micro Isotope Power Sources

International Nuclear Information System (INIS)

Heshmatpour, Ben; Lieberman, Al; Khayat, Mo; Leanna, Andrew; Dobry, Ted

2008-01-01

Promising design concepts for milliwatt (mW) size micro isotope power sources (MIPS) are being sought for use in various space and terrestrial applications, including a multitude of future NASA scientific missions and a range of military applications. To date, the radioisotope power sources (RPS) used on various space and terrestrial programs have provided power levels ranging from one-half to several hundred watts. In recent years, the increased use of smaller spacecraft and planned new scientific space missions by NASA, special terrestrial and military applications suggest the need for lower power, including mW level, radioisotope power sources. These power sources have the potential to enable such applications as long-lived meteorological or seismological stations distributed across planetary surfaces, surface probes, deep space micro-spacecraft and sub-satellites, terrestrial sensors, transmitters, and micro-electromechanical systems. The power requirements are in the range of 1 mW to several hundred mW. The primary technical requirements for space applications are long life, high reliability, high specific power, and high power density, and those for some special military uses are very high power density, specific power, reliability, low radiological induced degradation, and very low radiation leakage. Thermoelectric conversion is of particular interest because of its technological maturity and proven reliability. This paper summarizes the thermoelectric, thermal, and radioisotope heat source designs and presents the corresponding performance for a number of mW size thermoelectric micro isotope power sources

Impedance Source Power Electronic Converters

DEFF Research Database (Denmark)

Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding...

Intermittency in e+e- and lepton-hadron collisions

International Nuclear Information System (INIS)

Sugano, K.

1990-01-01

The intermittency data in e + e - and lepton-hadron collisions are reviewed. The power-law behavior of the moments has been established by various e + e - experiments and a μp experiment. The intermittency in the two-dimensional space of rapidity and azimuthal angle is much stronger than in the rapidity space only. The neutrino-nucleus data indicate significant effects from nuclear reinteractions. The LUND parton shower model fits the data better than the matrix element model without special retuning. The relations among the moments of different orders are in good agreement with the predictions by the negative binomial and pure birth distributions. The origin of the intermittency in e + e - and μp collisions is consistent with the self-similar cascade mechanism of jet formation. 11 refs., 7 figs

Reducing the market impact of large shares of intermittent energy in Denmark

International Nuclear Information System (INIS)

Klinge Jacobsen, Henrik; Zvingilaite, Erika

2010-01-01

The increasing prevalence of renewable and intermittent energy sources in the electricity system is creating new challenges for the interaction of the system. In Denmark, high renewable shares have been achieved without great difficulty, mainly due to the flexibility of the nearby Nordic hydro-power dominated system. Further increases in the share of renewable energy sources require that additional options are considered to facilitate integration with the lowest possible cost. With large shares of intermittent energy, the impact can be observed on wholesale prices, giving both lower prices and higher volatility. A lack of wind that causes high prices is rarely seen because long periods without wind are uncommon. Therefore we focus on the low price effects and the increased value of flexible demand options. On the supply side, there is an increase in the value of other flexible generation technologies and the attractiveness of additional interconnection capacity. This paper also analyses options for increasing the flexibility of heat generation involving large and decentralized CHP plants and heat generation based on electricity. The incentives that the market provides for shifting demand and using electricity for heat production are discussed based on the variability of prices observed from 2006 to 2008.

Intermittent search strategies

Science.gov (United States)

Bénichou, O.; Loverdo, C.; Moreau, M.; Voituriez, R.

2011-01-01

This review examines intermittent target search strategies, which combine phases of slow motion, allowing the searcher to detect the target, and phases of fast motion during which targets cannot be detected. It is first shown that intermittent search strategies are actually widely observed at various scales. At the macroscopic scale, this is, for example, the case of animals looking for food; at the microscopic scale, intermittent transport patterns are involved in a reaction pathway of DNA-binding proteins as well as in intracellular transport. Second, generic stochastic models are introduced, which show that intermittent strategies are efficient strategies that enable the minimization of search time. This suggests that the intrinsic efficiency of intermittent search strategies could justify their frequent observation in nature. Last, beyond these modeling aspects, it is proposed that intermittent strategies could also be used in a broader context to design and accelerate search processes.

Thermoelectric power generator for variable thermal power source

Science.gov (United States)

Bell, Lon E; Crane, Douglas Todd

2015-04-14

Traditional power generation systems using thermoelectric power generators are designed to operate most efficiently for a single operating condition. The present invention provides a power generation system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the power generator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Uniform decrease of alpha-global field power induced by intermittent photic stimulation of healthy subjects

Directory of Open Access Journals (Sweden)

Rau R.

2002-01-01

Full Text Available Nineteen-channel EEGs were recorded from the scalp surface of 30 healthy subjects (16 males and 14 females, mean age: 34 years, SD: 11.7 years at rest and under trains of intermittent photic stimulation (IPS at rates of 5, 10 and 20 Hz. Digitalized data were submitted to spectral analysis with fast fourier transformation providing the basis for the computation of global field power (GFP. For quantification, GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data obtained under IPS. All subjects showed a photic driving effect at each rate of stimulation. GFP data were normally distributed, whereas ratios from photic driving effect data showed no uniform behavior due to high interindividual variability. Suppression of alpha-power after IPS with 10 Hz was observed in about 70% of the volunteers. In contrast, ratios of alpha-power were unequivocal in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP with 20-Hz IPS by alpha-GFP at rest (R = alpha-GFP IPS/alpha-GFPrest thus resulted in ratios lower than 1. We conclude that ratios from GFP data with 20-Hz IPS may provide a suitable paradigm for further investigations.

Intermittent 20-HZ-photic stimulation leads to a uniform reduction of alpha-global field power in healthy volunteers.

Science.gov (United States)

Rau, R; Raschka, C; Koch, H J

2001-01-01

19-channel-EEGs were recorded from scalp surface of 30 healthy subjects (16m, 14f, mean age: 34 ys, SD: 11.7 ys) at rest and under IPS (Intermittent Photic Stimulation) at rates of 5, 10 and 20 Hertz (Hz). Digitalized data underwent spectral analysis with fast fourier transfomation (FFT) yielding the basis for the computation of global field power (GFP). For quantification GFP values in the frequency ranges of 5, 10 and 20 Hz at rest were divided by the corresponding data gained under IPS. While ratios from PDE data showed no stable parameter due to high interindividual variability, ratios of alpha-power turned out to be uniform in all subjects: IPS at 20 Hz always led to a suppression of alpha-power. Dividing alpha-GFP at rest by alpha-GFP under 20-Hz IPS thus resulted in a ratio paradigma.

The Effect of High Intensity Intermittent Exercise on Power Output for the Upper Body

Directory of Open Access Journals (Sweden)

Leonie Harvey

2015-06-01

Full Text Available The aim of the present study was to examine and measure high intensity, intermittent upper body performance, in addition to identifying areas of the body that affect the variance in total work done during the 5 × 6 s sprint test. Fifteen males completed an upper body 5 × 6 s sprint test on a modified electro-magnetically braked cycle ergometer, which consisted of five maximal effort sprints, each 6 s in duration, separated by 24 s of passive recovery. A fly wheel braking force corresponding to 5% of the participants’ body weight was used as the implemented resistance level. Body composition was measured using dual-energy X-ray absorptiometry (DEXA. Percent (% decrement was calculated as 100 − (Total work/ideal work × 100. Significant (P < 0.05 differences were found between sprints for both absolute and relative (W, W·kg−1, W·kg−1 Lean body mass (LBM and W·kg−1 Upper body lean body mass (UBLBM peak (PP and mean (MP power. The % decrement in total work done over the five sprints was 11.4%. Stepwise multiple linear regression analysis revealed that UBLBM accounts for 87% of the variance in total work done during the upper body 5 × 6 s sprint test. These results provide a descriptive analysis of upper body, high intensity intermittent exercise, demonstrating that PP and MP output decreased significantly during the upper body 5 × 6 s sprint test.

The Railgun and Its Power Source,

Science.gov (United States)

1987-06-01

inductor 66 3.1.3 The ANU homopolar generator power source 67 3.1.4 Features of an ideal power source 69 3.1.5 Desirable power source pulse energy...3.3.2 Homopolar generators 75 3.3.3 Ordinary large alternators 77 3.3.4 The compulsator 77 3.4 Explosive magnetic flux compression 80 3.5 Minimum mass of...discharge of lead-acid batteries 99 4.4.4 Design and performance of a high rate lead-acid cell 101 4.5 Motor -generator instead of batteries 103 4.5.1

Evidence for intermittency and a truncated power law from highly resolved aphid movement data.

Science.gov (United States)

Mashanova, Alla; Oliver, Tom H; Jansen, Vincent A A

2010-01-06

Power laws are increasingly used to describe animal movement. Despite this, the use of power laws has been criticized on both empirical and theoretical grounds, and alternative models based on extensions of conventional random walk theory (Brownian motion) have been suggested. In this paper, we analyse a large volume of data of aphid walking behaviour (65,068 data points), which provides a highly resolved dataset to investigate the pattern of movement. We show that aphid movement is intermittent--with alternations of a slow movement with frequent change of direction and a fast, relatively directed movement--and that the fast movement consists of two phases--a strongly directed phase that gradually changes into an uncorrelated random walk. By measuring the mean-squared displacement and the duration of non-stop movement episodes we found that both spatial and temporal aspects of aphid movement are best described using a truncated power law approach. We suggest that the observed spatial pattern arises from the duration of non-stop movement phases rather than from correlations in turning angles. We discuss the implications of these findings for interpreting movement data, such as distinguishing between movement and non-movement, and the effect of the range of data used in the analysis on the conclusions.

Bidding strategies for virtual power plants considering CHPs and intermittent renewables

International Nuclear Information System (INIS)

Zapata Riveros, J.; Bruninx, K.; Poncelet, K.; D’haeseleer, W.

2015-01-01

Highlights: • A stochastic optimization evaluates the optimal bidding strategy of a VPP. • Three different strategies were assessed: ‘static’, ‘flexible DA’ and ‘flexible RT’. • The ‘flexible RT’ attains the largest profits. It adapts the VPP output in real-time. - Abstract: Energy efficiency and renewable-energy sources (RES) are fundamental parts of the European energy policy. For this reason, efficient distributed generation technologies such as combined heat and power coupled to district heating (CHP–DH) and RES based electricity are largely promoted. Additionally, the flexibility that CHP–DH offers to the power system is seen as an option to balance the intermittent output of RES-based generation. This could be done by aggregating RES based electricity generation and CHP DH in a virtual power plant (VPP). In this framework, the present work presents a methodology to evaluate the optimal bidding strategy of a VPP composed of a CHP–DH and RES based generators. The objective is to investigate the optimal bidding strategy for a VPP that uses CHP DH to compensate for the uncertainties regarding RES-based electricity generation and market prices. The VPP operator nominates its energy to the day ahead market the day before the actual delivery (D-1). In real time, any deviation from the day-ahead schedule is settled in the imbalance market. The uncertainties are modeled using a two stage stochastic programming approach. Three different bidding strategies are studied: ‘static’, ‘flexible DA’ and ‘flexible RT’. The major difference between the studied strategies lies in the dispatch decisions. The ‘static’ strategy does not adjust the scheduled output of the CHP. Whereas, the ‘flexible DA’ and ‘flexible RT’ strategies differ from each other in terms of the information available at the moment of performing the reschedule (second stage decision). The ‘flexible DA’ reschedules the CHP output for the whole day assuming

Intermittent characteristics in coupling between turbulence and zonal flows

International Nuclear Information System (INIS)

Fujisawa, A; Shimizu, A; Nakano, H; Ohshima, S; Itoh, K; Nagashima, Y; Itoh, S-I; Iguchi, H; Yoshimura, Y; Minami, T; Nagaoka, K; Takahashi, C; Kojima, M; Nishimura, S; Isobe, M; Suzuki, C; Akiyama, T; Ido, T; Matsuoka, K; Okamura, S; Diamond, P H

2007-01-01

An extended application of Gabour's wavelet to bicoherence analysis succeeds in resolving the instantaneous structure of three wave couplings between disparate scale electric field fluctuations in the high temperature core in a toroidal plasma device named the compact helical system. The obtained results quantify an intermittent linkage between turbulence and zonal flows-a highlighted issue in the present plasma research. This is the first demonstration that the intermittent nature of the three wave coupling should underlie the turbulence power modulation due to zonal flows

Observation of intermittent transition by electrode biasing in Heliotron J

International Nuclear Information System (INIS)

Shimizu, Kosuke; Kitajima, Sumio; Okamoto, Atsushi

2015-01-01

We observed intermittent increases in the electrode current in electrode biasing experiments in Heliotron J. In addition, electron density and floating potential showed pulsating behavior associated with the electrode current. The relation between line density and electrode current and that between floating potential and electrode current showed a hysteresis feature in transitions. Then it is evident that the pulsating behavior was the intermittent transition between two distinctive states. We also observed the mode (∼10 kHz) that accompanied the pulsating behavior in the power spectrum density of the floating potential and ion saturation current obtained via fast Fourier transform. The electron density gradient increased, and subsequently the power spectrum density of the fluctuation increased. (author)

Power quality enhancement of renewable energy source power network using SMES system

International Nuclear Information System (INIS)

Seo, H.R.; Kim, A.R.; Park, M.; Yu, I.K.

2011-01-01

Power quality enhancement of a renewable energy source power network is performed by a real-toroidal-type SMES coil. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation. The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality. This paper deals with power quality enhancement of renewable energy source power network using SMES system and describes the operation characteristics of HTS SMES system using real-toroidal-type SMES coil for smoothening the fluctuation of large-scale renewable energy source such as photovoltaic (PV) power generation system. It generates maximum power of PV array under various weather conditions. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The SMES unit is controlled according to the PV array output and the utility power quality conditions. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation (PHILS). The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality in power network including large-scale renewable energy source, especially PV power generation system.

New developments in RF power sources

International Nuclear Information System (INIS)

Miller, R.H.

1994-06-01

The most challenging rf source requirements for high-energy accelerators presently being studied or designed come from the various electron-positron linear collider studies. All of these studies except TESLA (the superconducting entry in the field) have specified rf sources with much higher peak powers than any existing tubes at comparable high frequencies. While circular machines do not, in general, require high peak power, the very high luminosity electron-positron rings presently being designed as B factories require prodigious total average rf power. In this age of energy conservation, this puts a high priority on high efficiency for the rf sources. Both modulating anodes and depressed collectors are being investigated in the quest for high efficiency at varying output powers

Towards Holistic Power Distribution System Validation and Testing – An Overview and Discussion of Different Possibilities

DEFF Research Database (Denmark)

Strasser, T.; Andrén, F.; Lauss, G.

2016-01-01

Renewable energy sources are key enablers to decrease greenhouse gas emissions and to cope with the anthropogenic global warming. Their intermittent behaviour and limited storage capabilities present challenges to power system operators in maintaining the high level of power quality and reliability...

Power source with spark-safe outlet

Energy Technology Data Exchange (ETDEWEB)

Tsesarenko, N P; Alekhin, A V

1982-01-01

The invention refers to the technique of electrical monitoring and control in systems operating in a spark-safe medium (for example, in coal mines). A more accurate area of application is mobile objects with autonomous source of electricity (mine diesel locomotives, battery electric locomotives etc.). The purpose of the invention is to simplify and to improve the reliability of the planned device, and also to expand the area of application for conditions when it is powered from an autonomous generator of direct voltage. This goal is achieved because the power source with spark-safe outlet (the source contains a thyristor of advance disconnection, connected by anode to the delimiting throttle, one outlet of which is connected to the capacitor included between the controlling electrode and the anode of the thyristor, and the capacitor is connected through the resistor parallel to the outlet clamps of the source, while the thyristor of emergency protection connected parallel to the inlet clamps of the power source) is additionally equipped with a current sensor, hercon, transistor key (included in series in the power circuit) and optron, whose emitter is connected parallel to the current sensor connected in series to the inlet of the power source, while the receiver of the optron is connected in a circuit for controlling the thyristor of emergency protection. Hercon is built into the core of the delimiting throttle and is connected to the circuit for controlling the transistor key.

On the physics of power, energy and economics of renewable electric energy sources - Part II

International Nuclear Information System (INIS)

Skoglund, Annika; Leijon, Mats; Waters, Rafael; Rehn, Alf; Lindahl, Marcus

2010-01-01

Renewable Energy Technologies (RETs) are often recognized as less competitive than traditional electric energy conversion systems. Obstacles with renewable electric energy conversion systems are often referred to the intermittency of the energy sources and the relatively high maintenance cost. However, due to an intensified discourse on climate change and its effects, it has from a societal point of view, become more desirable to adopt and install CO 2 neutral power plants. Even if this has increased the competitiveness of RETs in a political sense, the new goals for RET installations must also be met with economical viability. We propose that the direction of technical development, as well as the chosen technology in new installations, should not primarily be determined by policies, but by the basic physical properties of the energy source and the associated potential for inexpensive energy production. This potential is the basic entity that drives the payback of the investment of a specific RET power plant. With regard to this, we argue that the total electric energy conversion system must be considered if effective power production is to be achieved, with focus on the possible number of full loading hours and the Degree of Utilization. This will increase the cost efficiency and economical competitiveness of RET investments, and could enhance faster diffusion of new innovations and installations without over-optimistic subsidies. This paper elaborates on the overall problem of the economy of renewable electric energy conversion systems by studying the interface between physics, engineering and economy reported for RET power plants in different scientific publications. The core objective is to show the practical use of the Degree of Utilization and how the concept is crucial for the design and economical optimization disregarding subsidies. The results clearly indicate that the future political regulative frameworks should consider the choice of renewable energy

Electrochemical Power Sources

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 7. Electrochemical Power Sources - Rechargeable Batteries. A K Shukla S K Martha. General Article Volume 6 Issue 7 July 2001 pp 52-63. Fulltext. Click here to view fulltext PDF. Permanent link:

Complex economic dynamics: Chaotic saddle, crisis and intermittency

International Nuclear Information System (INIS)

Chian, Abraham C.-L.; Rempel, Erico L.; Rogers, Colin

2006-01-01

Complex economic dynamics is studied by a forced oscillator model of business cycles. The technique of numerical modeling is applied to characterize the fundamental properties of complex economic systems which exhibit multiscale and multistability behaviors, as well as coexistence of order and chaos. In particular, we focus on the dynamics and structure of unstable periodic orbits and chaotic saddles within a periodic window of the bifurcation diagram, at the onset of a saddle-node bifurcation and of an attractor merging crisis, and in the chaotic regions associated with type-I intermittency and crisis-induced intermittency, in non-linear economic cycles. Inside a periodic window, chaotic saddles are responsible for the transient motion preceding convergence to a periodic or a chaotic attractor. The links between chaotic saddles, crisis and intermittency in complex economic dynamics are discussed. We show that a chaotic attractor is composed of chaotic saddles and unstable periodic orbits located in the gap regions of chaotic saddles. Non-linear modeling of economic chaotic saddle, crisis and intermittency can improve our understanding of the dynamics of financial intermittency observed in stock market and foreign exchange market. Characterization of the complex dynamics of economic systems is a powerful tool for pattern recognition and forecasting of business and financial cycles, as well as for optimization of management strategy and decision technology

Voltage resonant inverter as a power source

OpenAIRE

Lupenko, Anatoliy; Stakhiv, Petro

2014-01-01

The operation mode of a voltage resonant inverter as a power source with variable load is analyzed. In order to reduce load power variations, an approach to development of the inverter’s load power response based on providing similar positive and negative power deviations from its nominal value has been proposed. The design procedure for resonant inverter with open loop structure as a power source has been elaborated. For a high pressure sodium lamp as a load, the power deviation of about 4% ...

Wind farm - A power source in future power systems

DEFF Research Database (Denmark)

Chen, Zhe; Blaabjerg, Frede

2009-01-01

wind turbines and wind farms, and then introduces the wind power development and wind farms. An optimization platform for designing electrical systems of offshore wind farms is briefed. The major issues related to the grid connection requirements and the operation of wind turbines/farms in power......The paper describes modern wind power systems, introduces the issues of large penetration of wind power into power systems, and discusses the possible methods of making wind turbines/farms act as a power source, like conventional power plants in power systems. Firstly, the paper describes modern...... systems are illustrated....

Review of available power sources

International Nuclear Information System (INIS)

Beard, Carl

2006-01-01

Klystrons and triodes have been the accepted choice for particle accelerators because they produce high power RF and offer high gain (60 dB) with efficiencies of ∼50%. Although fairly new to the market, inductive output tubes (IOTs) have become available at L-band frequencies and have maintained their high efficiency. The development of superconducting RF at the L-band frequency allows IOTs to become the choice for future accelerator programs. Due to the operational nature of SRF technology in energy recovery mode, there is no longer the requirement for large amounts of RF power from single sources. This report reviews some of the developments in RF power sources suitable for energy recovery linacs (ERLs)

Biofuel Cells – Alternative Power Sources

International Nuclear Information System (INIS)

Babanova, Sofia; Yolina Hubenova; Mario Mitov

2009-01-01

Energy generation from renewable sources and effective waste treatment are two key challenges for the sustainable development. Microbiological (or Bio-) Fuel Cells provide an elegant solution by linking both tasks. Biofuel cells, which can directly generate electricity from biodegradable substances, have rapidly gained increasing research attention. Widely available fuel sources and moderate operational conditions make them promising in renewable energy generation, wastewater treatment, power sources for remote devices, etc. This paper reviews the use of microorganisms as biocatalysts in microbiological fuel cells. The principle of biofuel cells and their construction elements are discussed. Keywords: alternative power sources, biofuel cells, biocatalysts

Improvement of active filter for HIMAC power sources

Energy Technology Data Exchange (ETDEWEB)

Kumada, Masayuki [National Inst. of Radiological Sciences, Chiba (Japan); Kubo, Hiroshi; Furuzeki, Shoichiro; Kanazawa, Toru

1996-03-01

For the power sources of the synchrotron electromagnets for the heavy particle beam cancer therapy apparatus HIMAC in National Institute of Radiological Science, in order to stabilize the taken-out beam, the ripple property as low as below 1 x 10{sup -6} is required. As for this electromagnet power sources, various devices were applied to lower ripples, and the required specifications have been satisfied. Also the beam spill is stable, but slight variation has been observed, therefore, by improving the performance of the active filter, the ripples were improved. The specifications of the electromagnet power sources and the whole constitution of the power source system are shown. In the HIMAC power sources, the means for having realized the low ripple performance so far are explained. Those are the absorption of the ineffective power generated from the power sources, the control of the ripples of common made due to the transducer thyristor, and the sure compensation of ripples by the control circuit for the power sources. By adding the band pass filters to the active filter, its characteristics were improved. As the result, 1200 Hz ripple component was reduced by 41 db, thus the sufficient effect was obtained. Hereafter, by the high sensitivity measurement of the current of electromagnets and the evaluation of magnetic fields, the validity will be evaluated. (K.I.)

Miniaturized radioisotope solid state power sources

Science.gov (United States)

Fleurial, J.-P.; Snyder, G. J.; Patel, J.; Herman, J. A.; Caillat, T.; Nesmith, B.; Kolawa, E. A.

2000-01-01

Electrical power requirements for the next generation of deep space missions cover a wide range from the kilowatt to the milliwatt. Several of these missions call for the development of compact, low weight, long life, rugged power sources capable of delivering a few milliwatts up to a couple of watts while operating in harsh environments. Advanced solid state thermoelectric microdevices combined with radioisotope heat sources and energy storage devices such as capacitors are ideally suited for these applications. By making use of macroscopic film technology, microgenrators operating across relatively small temperature differences can be conceptualized for a variety of high heat flux or low heat flux heat source configurations. Moreover, by shrinking the size of the thermoelements and increasing their number to several thousands in a single structure, these devices can generate high voltages even at low power outputs that are more compatible with electronic components. Because the miniaturization of state-of-the-art thermoelectric module technology based on Bi2Te3 alloys is limited due to mechanical and manufacturing constraints, we are developing novel microdevices using integrated-circuit type fabrication processes, electrochemical deposition techniques and high thermal conductivity substrate materials. One power source concept is based on several thermoelectric microgenerator modules that are tightly integrated with a 1.1W Radioisotope Heater Unit. Such a system could deliver up to 50mW of electrical power in a small lightweight package of approximately 50 to 60g and 30cm3. An even higher degree of miniaturization and high specific power values (mW/mm3) can be obtained when considering the potential use of radioisotope materials for an alpha-voltaic or a hybrid thermoelectric/alpha-voltaic power source. Some of the technical challenges associated with these concepts are discussed in this paper. .

46 CFR 112.01-15 - Temporary emergency power source.

Science.gov (United States)

2010-10-01

... EMERGENCY LIGHTING AND POWER SYSTEMS Definitions of Emergency Lighting and Power Systems § 112.01-15 Temporary emergency power source. A temporary emergency power source is one of limited capacity that carries... 46 Shipping 4 2010-10-01 2010-10-01 false Temporary emergency power source. 112.01-15 Section 112...

A novel inclusion of intermittent generation resources in long term energy auctions

International Nuclear Information System (INIS)

Marambio, Rodrigo; Rudnick, Hugh

2017-01-01

Long term energy auctions are positioning as a valuable tool in order to attract new investments into power systems, especially in Latin American countries where emergent economies characteristics and their correspondent risks are usually present. Even though the focus of these auctions is the long term, there are short term issues involved which actual auction designs fail to include, resulting in an energy allocation that is not necessarily optimal for the system, a condition which becomes more evident in the presence of intermittent renewable technologies. A novel mechanism is formulated to obtain the optimal allocation in long term energy auctions, considering short term generation profiles from both intermittent and conventional base load technologies, and also their risk aversions. The proposed mechanism is developed and simulations are made for some scenarios in the Chilean power market, with different levels of renewable penetration. Significant cost savings are achieved for the final consumers in relation to energy purchases, in comparison with a mechanism that follows the demand profile. As more renewable intermittent capacity enters the power system it is evident the need for changes in the energy auctions allocation mechanisms, including elements to exploit the synergies among participants in the short term. - Highlights: • Risk management consideration in technology neutral auctions allocation. • Allocation mechanism in technology neutral auctions with intermittent technologies. • Renewable and conventional technologies energy auction offer curves. • Increase bid prices in auctions as a consequence of solar technology support.

Randomized trial of intermittent or continuous amnioinfusion for variable decelerations.

Science.gov (United States)

Rinehart, B K; Terrone, D A; Barrow, J H; Isler, C M; Barrilleaux, P S; Roberts, W E

2000-10-01

To determine whether continuous or intermittent bolus amnioinfusion is more effective in relieving variable decelerations. Patients with repetitive variable decelerations were randomized to an intermittent bolus or continuous amnioinfusion. The intermittent bolus infusion group received boluses of 500 mL of normal saline, each over 30 minutes, with boluses repeated if variable decelerations recurred. The continuous infusion group received a bolus infusion of 500 mL of normal saline over 30 minutes and then 3 mL per minute until delivery occurred. The ability of the amnioinfusion to abolish variable decelerations was analyzed, as were maternal demographic and pregnancy outcome variables. Power analysis indicated that 64 patients would be required. Thirty-five patients were randomized to intermittent infusion and 30 to continuous infusion. There were no differences between groups in terms of maternal demographics, gestational age, delivery mode, neonatal outcome, median time to resolution of variable decelerations, or the number of times variable decelerations recurred. The median volume infused in the intermittent infusion group (500 mL) was significantly less than that in the continuous infusion group (905 mL, P =.003). Intermittent bolus amnioinfusion is as effective as continuous infusion in relieving variable decelerations in labor. Further investigation is necessary to determine whether either of these techniques is associated with increased occurrence of rare complications such as cord prolapse or uterine rupture.

Radial evolution of the intermittency of density fluctuations in the fast solar wind

International Nuclear Information System (INIS)

Bruno, R.; D'Amicis, R.; Telloni, D.; Primavera, L.; Sorriso-Valvo, L.; Carbone, V.; Malara, F.; Veltri, P.; Pietropaolo, E.

2014-01-01

We study the radial evolution of the intermittency of density fluctuations in the fast solar wind. The study is performed by analyzing the plasma density measurements provided by Helios 2 in the inner heliosphere between 0.3 and 0.9 AU. The analysis is carried out by means of a complete set of diagnostic tools, including the flatness factor at different timescales to estimate intermittency, the Kolmogorov-Smirnov test to estimate the degree of intermittency, and the Fourier transform to estimate the power spectral densities of these fluctuations. Density fluctuations within the fast wind are rather intermittent and their level of intermittency, together with the amplitude of intermittent events, decreases with the distance from the Sun, at odds with the intermittency of both magnetic field and all other plasma parameters. Furthermore, the intermittent events are strongly correlated, exhibiting temporal clustering. This indicates that the mechanism underlying their generation departs from a time-varying Poisson process. A remarkable, qualitative similarity with the behavior of plasma density fluctuations obtained from a numerical study of the nonlinear evolution of parametric instability in the solar wind supports the idea that this mechanism has an important role in governing density fluctuations in the inner heliosphere.

Anomalous Power Flow and ``Ghost'' Sources

Science.gov (United States)

Monzon, Cesar

2008-08-01

It is demonstrated that EM radiation from complex sources can result in real power in restricted regions of space flowing back towards the sources, thereby mimicking “ghost” sources. This counterintuitive mechanism of radiation does not rely on backward waves, as ordinary waves carry the power. Ways to harness the effect by making it directional are presented, together with selected applications, of which deception is a prime example due to the nature of the phenomenon. The concept can be applied to other areas, such as mechanics, acoustics, etc., and can be realized with available technology.

Stirling/hydraulic artificial heart power source

International Nuclear Information System (INIS)

Johnston, R.P.; Bennett, A.; Emigh, S.G.; Griffith, W.R.; Noble, J.E.; Perrone, R.E.; White, M.A.; Martini, W.R.; Alexander, J.E.

1977-01-01

The REL power source combines the high efficiency of Stirling engines with the reliability, efficiency, and flexibility of hydraulic power transfer and control to ensure long system life and physiological effectiveness. Extended life testing has been achieved with an engine (2.6 years) and hydraulic actuator/controller (1.6 years). Peak power source efficiency is 15.5 percent on 5 to 10 watts delivered to the blood pump push plate with 33 watts steady thermal input. Planned incorporation of power source output control is expected to reduce daily average thermal input to 18 watts. Animal in-vivo tests with an assist heart have consistently demonstrated required performance by biological synchronization and effective ventricle relief. Volume and weight are 0.93 liter and 2.4 kg (excluding blood pump) with an additional 0.4 liter of low temperature foam insulation required to preclude tissue thermal damage. Carefully planned development of System 7 is expected to produce major reductions in size

Intermittent degradation and schizotypy

Directory of Open Access Journals (Sweden)

Matthew W. Roché

2015-06-01

Full Text Available Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-report questionnaires assessing schizotypy and psychological state variables (e.g., anxiety, depression, and their reaction times were recorded as they did so. Intermittent degradation was defined as the number of times a subject’s reaction time for questionnaire items met or exceeded three standard deviations from his or her mean reaction time after controlling for each item’s information processing load. Intermittent degradation scores were correlated with questionnaire scores. Our results indicate that intermittent degradation is associated with total scores on measures of positive and disorganized schizotypy, but unrelated to total scores on measures of negative schizotypy and psychological state variables. Intermittent degradation is interpreted as potentially derivative of schizotypy and a candidate endophenotypic marker worthy of continued research.

Fuel cell/electrochemical capacitor hybrid for intermittent high power applications

Energy Technology Data Exchange (ETDEWEB)

Jarvis, L P; Atwater, T B; Cygan, P J [Army Communications-Electronics Command (CECOM), Fort Monmouth, NJ (United States). Research and Development Center

1999-05-01

A hybrid power source was demonstrated to successfully power a simulated power load encountered in portable military electronics and communications equipment. The hybrid system consisted of a 25 W proton exchange membrane fuel cell (PEMFC) stack connected in parallel with a 70 F capacitor bank. The cyclic regime of 18.0 W for 2 min followed by 2.5 W for 18 min was chosen as the baseline for the simulation of power load. The operating potential cut-off voltage for pass/failure was set to 3.0 V. At room temperature (23-25 C), the PEMFC alone could not handle the described baseline regime with the PEMFC operating potential dropping below the cut-off voltage within 10 s. The hybrid, however, continuously powered the same regime for 25 h. Its operating potential never reached the voltage cut-off point, not even during the high load of 18.0 W. The tests with hybrid configuration were aborted after 25 h of operation with no signs of output degradation, suggesting that further extended operation was possible. (orig.)

Effects of Auxiliary-Source Connection in Multichip Power Module

DEFF Research Database (Denmark)

Li, Helong; Munk-Nielsen, Stig; Wang, Xiongfei

2017-01-01

the power loop and the gate loop like how the Kelvin-source connection does, owing to their involvement in the loop of the power source current. Three effects of the auxiliary-source connections are then analyzed, which are 1) the common source stray inductance reduction, 2) the transient drain......Auxiliary-source bond wires and connections are widely used in power modules with paralleled MOSFETs or IGBTs. This paper investigates the operation mechanism of the auxiliary-source connections in multichip power modules. It reveals that the auxiliary-source connections cannot fully decouple......-source current imbalance mitigation, and 3) the influence on the steady-state current distribution. Lastly, simulations and experimental results validate the theoretical analysis....

Primary frequency regulation supported by battery storage systems in power systems dominated by renewable energy sources

DEFF Research Database (Denmark)

Turk, Ana; Sandelic, Monika; Noto, Giancarlo

2018-01-01

replaced by intermittent renewable generators. Therefore, maintaining system quality and stability in terms of power system frequency control is one of the major challenges that requires new resources and their system integration. Battery energy storage systems (BESS), as fast-acting energy storage systems...

High power microwave source development

Science.gov (United States)

Benford, James N.; Miller, Gabriel; Potter, Seth; Ashby, Steve; Smith, Richard R.

1995-05-01

The requirements of this project have been to: (1) improve and expand the sources available in the facility for testing purposes and (2) perform specific tasks under direction of the Defense Nuclear Agency about the applications of high power microwaves (HPM). In this project the HPM application was power beaming. The requirements of this program were met in the following way: (1) We demonstrated that a compact linear induction accelerator can drive HPM sources at repetition rates in excess of 100 HZ at peak microwave powers of a GW. This was done for the relativistic magnetron. Since the conclusion of this contract such specifications have also been demonstrated for the relativistic klystron under Ballistic Missile Defense Organization funding. (2) We demonstrated an L band relativistic magnetron. This device has been used both on our single pulse machines, CAMEL and CAMEL X, and the repetitive system CLIA. (3) We demonstrated that phase locking of sources together in large numbers is a feasible technology and showed the generation of multigigawatt S-band radiation in an array of relativistic magnetrons.

Sinusoidal visuomotor tracking: intermittent servo-control or coupled oscillations?

Science.gov (United States)

Russell, D M; Sternad, D

2001-12-01

In visuomotor tasks that involve accuracy demands, small directional changes in the trajectories have been taken as evidence of feedback-based error corrections. In the present study variability, or intermittency, in visuomanual tracking of sinusoidal targets was investigated. Two lines of analyses were pursued: First, the hypothesis that humans fundamentally act as intermittent servo-controllers was re-examined, probing the question of whether discontinuities in the movement trajectory directly imply intermittent control. Second, an alternative hypothesis was evaluated: that rhythmic tracking movements are generated by entrainment between the oscillations of the target and the actor, such that intermittency expresses the degree of stability. In 2 experiments, participants (N = 6 in each experiment) swung 1 of 2 different hand-held pendulums, tracking a rhythmic target that oscillated at different frequencies with a constant amplitude. In 1 line of analyses, the authors tested the intermittency hypothesis by using the typical kinematic error measures and spectral analysis. In a 2nd line, they examined relative phase and its variability, following analyses of rhythmic interlimb coordination. The results showed that visually guided corrective processes play a role, especially for slow movements. Intermittency, assessed as frequency and power components of the movement trajectory, was found to change as a function of both target frequency and the manipulandum's inertia. Support for entrainment was found in conditions in which task frequency was identical to or higher than the effector's eigenfrequency. The results suggest that it is the symmetry between task and effector that determines which behavioral regime is dominant.

Selection of Power Sources for Portable Applications

NARCIS (Netherlands)

Flipsen, S.F.J.

2009-01-01

New power sources emerge very quickly. Implementation of hybrid power sources for portable electronics depends on the knowledge of industrial designers. For now this group has little understanding of fuel cells and especially fuel-cell hybrids. This slows down implementation and increases the chance

Power System Oscillatory Behaviors: Sources, Characteristics, & Analyses

Energy Technology Data Exchange (ETDEWEB)

Follum, James D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tuffner, Francis K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Dosiek, Luke A. [Union College, Schenectady, NY (United States); Pierre, John W. [Univ. of Wyoming, Laramie, WY (United States)

2017-05-17

This document is intended to provide a broad overview of the sources, characteristics, and analyses of natural and forced oscillatory behaviors in power systems. These aspects are necessarily linked. Oscillations appear in measurements with distinguishing characteristics derived from the oscillation’s source. These characteristics determine which analysis methods can be appropriately applied, and the results from these analyses can only be interpreted correctly with an understanding of the oscillation’s origin. To describe oscillations both at their source within a physical power system and within measurements, a perspective from the boundary between power system and signal processing theory has been adopted.

An Enhanced Droop Control Scheme for Resilient Active Power Sharing in Paralleled Two-Stage PV Inverter Systems

DEFF Research Database (Denmark)

Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

2016-01-01

Traditional droop-controlled systems assume that the generators are able to provide sufficient power as required. This is however not always true, especially in renewable systems, where the energy sources (e.g., photovoltaic source) may not be able to provide enough power (or even loss of power...... generation) due to the intermittency. In that case, unbalance in active power generation may occur among the paralleled systems. Additionally, most droop-controlled systems have been assumed to be a single dc-ac inverter with a fixed dc input source. The dc-dc converter as the front-end of a two...

Smart intermittency-friendly cogeneration: Techno-economic performance of innovative double storage concept for integrating compression heat pumps in distributed cogeneration

DEFF Research Database (Denmark)

Blarke, Morten

2011-01-01

cogeneration plants rather than central power plants are giving way for wind power in the electricity mix. Could intermittent renewables be a threat to the system-wide energy, economic and environmental benefits that distributed cogeneration have to offer? This paper investigates how existing cogeneration...... plants may adapt their plant design and operational strategy to improve the co-existence between cogeneration and intermittent renewables. A novel intermittency-friendly and super-efficient concept in cogeneration is presented that involves integrating a high-pressure compression heat pump using heat...

Sound power radiated by sources in diffuse fields

DEFF Research Database (Denmark)

Polack, Jean-Dominique

2000-01-01

Sound power radiated by sources at low frequency notoriously depends on source position. We sampled the sound field of a rectangular room at 18 microphone and 4 source positions. Average power spectra were extrapolated from the reverberant field, taking into account the frequency dependent...

Expert assessment of advanced power sources. Contract report

International Nuclear Information System (INIS)

Gardner, C.L.

2007-07-01

Although DRDC published an exhaustive technical report (in August 2001) on technology trends in advanced power sources projected out to the year 2020, the terrorist attacks on the US on September 11, 2001 (and the consequent, augmented and more broadly-based defence and national security posture adopted by the CF/DND), together with rapid developments in power source technologies over the past five years, internationally, prompted DRDC to update the 2001 report, on a selected number of power source technologies or applications and to provide further guidance to DRDC's Advanced Power Source R and D program. Eight wide-ranging, power source technologies or applications were investigated, using the technique of 'expert elicitation' (that is, using independent experts in the various and diverse technological fields), based on a standardized questionnaire, augmented by the contractor's own expertise (and his overall analysis of the experts' responses) in these diverse areas. In addition, each expert was asked about his/her view on the likely role of nanotechnology in each technological area or application. Following collection and analysis of all the data, the contractor made recommendations on the ability of each power source to meet the future requirements of the CF/DND, taking into account the Technology Readiness Level, for each technology or application

Circuit implementation and multiform intermittency in a hyper-chaotic model extended from the Lorenz system

International Nuclear Information System (INIS)

Shi-Jian, Cang; Zeng-Qiang, Chen; Wen-Juan, Wu

2009-01-01

This paper presents a non-autonomous hyper-chaotic system, which is formed by adding a periodic driving signal to a four-dimensional chaotic model extended from the Lorenz system. The resulting non-autonomous hyper-chaotic system can display any dynamic behaviour among the periodic orbits, intermittency, chaos and hyper-chaos by controlling the frequency of the periodic signal. The phenomenon has been well demonstrated by numerical simulations, bifurcation analysis and electronic circuit realization. Moreover, the system is concrete evidence for the presence of Pomeau–Manneville Type-I intermittency and crisis-induced intermittency. The emergence of a different type of intermittency is similarly subjected to the frequency of periodic forcing. By statistical analysis, power scaling laws consisting in different intermittency are obtained for the lifetime in the laminar state between burst states

Events as Power Source: Wireless Sustainable Corrosion Monitoring

OpenAIRE

Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

2013-01-01

This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is ...

Energy sources and power plants

International Nuclear Information System (INIS)

Schulz, Detlef; Schulz, Karen

2013-01-01

Energy is obtained from various energy sources (coal, petroleum, natural gas, nuclear fuels, wind energy, solar energy, hydro power, biomass, geothermal energy). These differ in each case with respect to their availability, methods of their production and the required power plant technologies. As technologies of the future fuel cells and nuclear fusion are traded. [de

Coal-fired Power Plants with Flexible Amine-based CCS and Co-located Wind Power: Environmental, Economic and Reliability Outcomes

Science.gov (United States)

Bandyopadhyay, Rubenka

Carbon Capture and Storage (CCS) technologies provide a means to significantly reduce carbon emissions from the existing fleet of fossil-fired plants, and hence can facilitate a gradual transition from conventional to more sustainable sources of electric power. This is especially relevant for coal plants that have a CO2 emission rate that is roughly two times higher than that of natural gas plants. Of the different kinds of CCS technology available, post-combustion amine based CCS is the best developed and hence more suitable for retrofitting an existing coal plant. The high costs from operating CCS could be reduced by enabling flexible operation through amine storage or allowing partial capture of CO2 during high electricity prices. This flexibility is also found to improve the power plant's ramp capability, enabling it to offset the intermittency of renewable power sources. This thesis proposes a solution to problems associated with two promising technologies for decarbonizing the electric power system: the high costs of the energy penalty of CCS, and the intermittency and non-dispatchability of wind power. It explores the economic and technical feasibility of a hybrid system consisting of a coal plant retrofitted with a post-combustion-amine based CCS system equipped with the option to perform partial capture or amine storage, and a co-located wind farm. A techno-economic assessment of the performance of the hybrid system is carried out both from the perspective of the stakeholders (utility owners, investors, etc.) as well as that of the power system operator. (Abstract shortened by ProQuest.).

Time limit and time at VO2max' during a continuous and an intermittent run.

Science.gov (United States)

Demarie, S; Koralsztein, J P; Billat, V

2000-06-01

The purpose of this study was to verify, by track field tests, whether sub-elite runners (n=15) could (i) reach their VO2max while running at v50%delta, i.e. midway between the speed associated with lactate threshold (vLAT) and that associated with maximal aerobic power (vVO2max), and (ii) if an intermittent exercise provokes a maximal and/or supra maximal oxygen consumption longer than a continuous one. Within three days, subjects underwent a multistage incremental test during which their vVO2max and vLAT were determined; they then performed two additional testing sessions, where continuous and intermittent running exercises at v50%delta were performed up to exhaustion. Subject's gas exchange and heart rate were continuously recorded by means of a telemetric apparatus. Blood samples were taken from fingertip and analysed for blood lactate concentration. In the continuous and the intermittent tests peak VO2 exceeded VO2max values, as determined during the incremental test. However in the intermittent exercise, peak VO2, time to exhaustion and time at VO2max reached significantly higher values, while blood lactate accumulation showed significantly lower values than in the continuous one. The v50%delta is sufficient to stimulate VO2max in both intermittent and continuous running. The intermittent exercise results better than the continuous one in increasing maximal aerobic power, allowing longer time at VO2max and obtaining higher peak VO2 with lower lactate accumulation.

Intermittency in Complex Flows

Science.gov (United States)

Ben Mahjoub, Otman; Redondo, Jose M.

2017-04-01

Experimental results of the complex turbulent wake of a cilinder in 2D [1] and 3D flows [2] were used to investigate the scaling of structure functions, similar research was also performed on wave propagation and breaking in the Ocean [3], in the the stratified Atmosphere (ABL) [4] and in a 100large flume (UPC) for both regular and irregular waves, where long time series of waves propagating and generating breaking turbulence velocity rms and higher order measurements were taken in depth. [3,5] by means of a velocimeter SONTEK3-D. The probability distribution functions of the velocity differences and their non Gaussian distribution related to the energy spectrum indicate that irregularity is an important source of turbulence. From Kolmogorov's K41 and K61 intermittency correction: the p th-order longitudinal velocity structure function δul at scale l in the inertial range of three-dimensional fully developed turbulence is related by ⟨δup⟩ = ⟨(u(x+ l)- u(x))p⟩ ˜ ɛp0/3lp/3 l where ⟨...⟩ represents the spatial average over flow domain, with ɛ0 the mean energy dissipation per unit mass and l is the separation distance. The importance of the random nature of the energy dissipation led to the K62 theory of intermittency, but locality and non-homogeneity are key issues. p p/3 p/3 ξd ⟨δul⟩ ˜ ⟨ɛl ⟩l ˜ l and ξp = p 3 + τp/3 , where now ɛl is a fractal energy dissipation at scale l, τp/3 is the scaling of and ξp is the scaling exponent of the velocity structure function of order p. Both in K41 and K62, the structure functions of third order related to skewness is ξ3 = 1. But this is not true either. We show that scaling exponents ξp do deviate from early studies that only investigated homogeneous turbulence, where a large inertial range dominates. The use of multi-fractal analysis and improvements on Structure function calculations on standard Enhanced mixing is an essential property of turbulence and efforts to alter and to control

High power pulsed sources based on fiber amplifiers

Science.gov (United States)

Canat, Guillaume; Jaouën, Yves; Mollier, Jean-Claude; Bouzinac, Jean-Pierre; Cariou, Jean-Pierre

2017-11-01

Cladding-pumped rare-earth-doped fiber laser technologies are currently among the best sources for high power applications. Theses extremely compact and robust sources appoint them as good candidate for aeronautical and space applications. The double-clad (DC) fiber converts the poor beamquality of high-power large-area pump diodes from the 1st cladding to laser light at another wavelength guided in an active single-mode core. High-power coherent MOPA (Master Oscillator Power Amplifier) sources (several 10W CW or several 100W in pulsed regime) will soon be achieved. Unfortunately it also brings nonlinear effects which quickly impairs output signal distortions. Stimulated Brillouin scattering (SBS) and optical parametric amplification (OPA) have been shown to be strong limitations. Based on amplifier modeling and experiments we discuss the performances of these sources.

The Role of Visual Feedback on Power Output During Intermittent Wingate Testing in Ice Hockey Players

Directory of Open Access Journals (Sweden)

Petr Stastny

2018-04-01

Full Text Available Background: Visual feedback may help elicit peak performance during different types of strength and power testing, but its effect during the anaerobic Wingate test is unexplored. Therefore, the purpose of this study was to determine the effect of visual feedback on power output during a hockey-specific intermittent Wingate test (AnWT6x6 consisting of 6 stages of 6 s intervals with a 1:1 work-to-rest ratio. Methods: Thirty elite college-aged hockey players performed the AnWT6x6 with either constant (n = 15 visual feedback during all 6 stages (CVF or restricted (n = 15 visual feedback (RVF where feedback was shown only during the 2nd through 5th stages. Results: In the first stage, there were moderate-to-large effect sizes for absolute peak power (PP output and PP relative to body mass and PP relative to fat-free mass. However, the remaining stages (2–6 displayed small or negligible effects. Conclusions: These data indicate that visual feedback may play a role in optimizing power output in a non-fatigued state (1st stage, but likely does not play a role in the presence of extreme neuromuscular fatigue (6th stage during Wingate testing. To achieve the highest peak power, coaches and researchers could provide visual feedback during Wingate testing, as it may positively influence performance in the early stages of testing, but does not result in residual fatigue or negatively affect performance during subsequent stages.

Economic feasibility constraints for renewable energy source power production

International Nuclear Information System (INIS)

Biondi, L.

1992-01-01

Suitable analysis criteria for use in economic feasibility studies of renewable energy source power plants are examined for various plant types, e.g., pumped storage hydroelectric, geothermal, wind, solar, refuse-fuelled, etc. The paper focusses on the impacts, on operating cost and rate structure, of the necessity, depending on demand characteristics, to integrate renewable energy source power production with conventional power production in order to effectively and economically meet peak power demand. The influence of commercialization and marketing trends on renewable energy source power plant economic feasibility are also taken into consideration

Power generation from low-temperature heat source

Energy Technology Data Exchange (ETDEWEB)

Lakew, Amlaku Abie

2012-07-01

The potential of low-temperature heat sources for power production has been discussed for decades. The diversity and availability of low-temperature heat sources makes it interesting for power production. The thermodynamic power cycle is one of the promising technologies to produce electricity from low-temperature heat sources. There are different working fluids to be used in a thermodynamic power cycle. Working fluid selection is essential for the performance of the power cycle. Over the last years, different working fluid screening criteria have been used. In broad speaking the screening criteria can be grouped as thermodynamic performance, component size requirement, economic performance, safety and environmental impact. Screening of working fluids at different heat source temperatures (80-200 Celsius degrees) using thermodynamic performance (power output and exergy efficiency) and component size (heat exchanger and turbine) is investigated. It is found that the 'best' working fluid depends on the criteria used and heat source temperature level. Transcritical power cycles using carbon dioxide as a working fluid is studied to produce power at 100 Celsius degrees. Carbon dioxide is an environmentally friendly refrigerant. The global warming potential of carbon dioxide is 1. Furthermore, because of its low critical temperature (31 Celsius degrees), carbon dioxide can operate in a transcritical power cycle for lower heat source temperatures. A transcritical configuration avoids the problem of pinching which otherwise would happened in subcritical power cycle. In the process, better temperature matching is achieved and more heat is extracted. Thermodynamic analysis of transcritical cycle is performed; it is found that there is an optimal operating pressure for highest net power output. The pump work is a sizable fraction of the work produced by the turbine. The effect of efficiency deterioration of the pump and the turbine is compared. When the

Intermittent Explosive Disorder

Directory of Open Access Journals (Sweden)

Lut Tamam

2011-09-01

Full Text Available Intermittent explosive disorder is an impulse control disorder characterized by the occurrence of discrete episodes of failure to resist aggressive impulses that result in violent assault or destruction of property. Though the prevalence intermittent explosive disorder has been reported to be relatively rare in frontier studies on the field, it is now common opinion that intermittent explosive disorder is far more common than previously thought especially in clinical psychiatry settings. Etiological studies displayed the role of both psychosocial factors like childhood traumas and biological factors like dysfunctional neurotransmitter systems and genetics. In differential diagnosis of the disorder, disorders involving agression as a symptom such as alcohol and drug intoxication, antisocial and borderline personality disorders, personality changes due to general medical conditions and behavioral disorder should be considered. A combination of pharmacological and psychotherapeutic approaches are suggested in the treatment of the disorder. This article briefly reviews the historical background, diagnostic criteria, epidemiology, etiology and treatment of intermittent explosive disorder.

Comparing microbial water quality in an intermittent and continuous piped water supply.

Science.gov (United States)

Kumpel, Emily; Nelson, Kara L

2013-09-15

Supplying piped water intermittently is a common practice throughout the world that increases the risk of microbial contamination through multiple mechanisms. Converting an intermittent supply to a continuous supply has the potential to improve the quality of water delivered to consumers. To understand the effects of this upgrade on water quality, we tested samples from reservoirs, consumer taps, and drinking water provided by households (e.g. from storage containers) from an intermittent and continuous supply in Hubli-Dharwad, India, over one year. Water samples were tested for total coliform, Escherichia coli, turbidity, free chlorine, and combined chlorine. While water quality was similar at service reservoirs supplying the continuous and intermittent sections of the network, indicator bacteria were detected more frequently and at higher concentrations in samples from taps supplied intermittently compared to those supplied continuously (p supply, with 0.7% of tap samples positive compared to 31.7% of intermittent water supply tap samples positive for E. coli. In samples from both continuously and intermittently supplied taps, higher concentrations of total coliform were measured after rainfall events. While source water quality declined slightly during the rainy season, only tap water from intermittent supply had significantly more indicator bacteria throughout the rainy season compared to the dry season. Drinking water samples provided by households in both continuous and intermittent supplies had higher concentrations of indicator bacteria than samples collected directly from taps. Most households with continuous supply continued to store water for drinking, resulting in re-contamination, which may reduce the benefits to water quality of converting to continuous supply. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mitigation of wind power fluctuations by intelligent response of demand and distributed generation

NARCIS (Netherlands)

MacDougall, P.A.; Warmer, C.; Kok, K.

2011-01-01

With the world becoming ever more conscious of the necessity for clean, sustainable energy sources, an increased proportion of energy produced by wind resources is expected. In the current power system, the integration of such large capacity of non-load-following and intermittent supply leads to

Intermittent heating of buildings

Energy Technology Data Exchange (ETDEWEB)

Kohonen, K

1983-02-01

Conditions for intermittent heating of buildings are considered both theoretically and experimentally. Thermal behaviour of buildings adn rooms in intermittent heating is simulated by a program based on the convective heat balance equation and by simplified RC-models. The preheat times and the heating energy savings compared with continuous heating are presented for typical lightweight, mediumweight and heavyweight classroom and office modules. Formulaes for estimating the oversizing of the radiator network, the maximum heat output of heat exchangers in district heating and the efficiency of heating boilers in intermittent heating are presented. The preheat times and heating energy savings with different heating control systems are determined also experimentally in eight existing buildings. In addition some principles for the planning and application of intermittent heating systems are suggested.

Design feasibility of an intermittent domestic energy store

Energy Technology Data Exchange (ETDEWEB)

Tahat, M.A. [Jordan Univ. of Sceince and Technology, Irbid (Jordan). Dept. of Mechanical Engineering; Babus`Haq, R.F.; O`Callaghan, P.W.; Probert, S.D. [Cranfield Univ., Bedford (United Kingdom). Dept. of Applied Energy

1995-09-01

In recent years, energy storage has been recognised as a potentially significant means by which primary energy consumption can be reduced in domestic, commercial and industrial processes. An intermittent domestic thermochemical heat pump, with a 5 kW{sub e} electric power output when employed as an energy store, is proposed. Different design options have been considered and their economic feasibilities evaluated. (author)

Impedance-Source Networks for Electric Power Conversion Part I

DEFF Research Database (Denmark)

Siwakoti, Yam P.; Peng, Fang Zheng; Blaabjerg, Frede

2015-01-01

power chain, which may improve the reliability and performance of the power system. The first part of this paper provides a comprehensive review of the various impedance-source-networks-based power converters and discusses the main topologies from an application point of view. This review paper...... is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers. A comprehensive review of various modeling, control, and modulation techniques for the impedance...

Advanced radioisotope power source options for Pluto Express

International Nuclear Information System (INIS)

Underwood, M.L.

1995-01-01

In the drive to reduce mass and cost, Pluto Express is investigating using an advanced power conversion technology in a small Radioisotope Power Source (RPS) to deliver the required mission power of 74 W(electric) at end of mission. Until this year the baseline power source under consideration has been a Radioisotope Thermoelectric Generator (RTG). This RTG would be a scaled down GPHS RTG with an inventory of 6 General Purpose Heat Sources (GPHS) and a mass of 17.8 kg. High efficiency, advanced technology conversion options are being examined to lower the power source mass and to reduce the amount of radioisotope needed. Three technologies are being considered as the advanced converter technology: the Alkali Metal Thermal-to-Electric Converter (AMTEC), Thermophotovoltaic (TPV) converters, and Stirling Engines. Conceptual designs for each of these options have been prepared. Each converter would require only 2 GPHSs to provide the mission power and would have a mass of 6.1, 7.2, and 12.4 kg for AMTEC, TPV, and Stirling Engines respectively. This paper reviews the status of each technology and the projected performance of an advanced RPS based on each technology. Based on the projected performance and spacecraft integration issues, Pluto Express would prefer to use the AMTEC based RPS. However, in addition to technical performance, selection of a power technology will be based on many other factors

Large Scale Integration of Renewable Power Sources into the Vietnamese Power System

Science.gov (United States)

Kies, Alexander; Schyska, Bruno; Thanh Viet, Dinh; von Bremen, Lueder; Heinemann, Detlev; Schramm, Stefan

2017-04-01

The Vietnamese Power system is expected to expand considerably in upcoming decades. Power capacities installed are projected to grow from 39 GW in 2015 to 129.5 GW by 2030. Installed wind power capacities are expected to grow to 6 GW (0.8 GW 2015) and solar power capacities to 12 GW (0.85 GW 2015). This goes hand in hand with an increase of the renewable penetration in the power mix from 1.3% from wind and photovoltaics (PV) in 2015 to 5.4% by 2030. The overall potential for wind power in Vietnam is estimated to be around 24 GW. Moreover, the up-scaling of renewable energy sources was formulated as one of the priorized targets of the Vietnamese government in the National Power Development Plan VII. In this work, we investigate the transition of the Vietnamese power system towards high shares of renewables. For this purpose, we jointly optimise the expansion of renewable generation facilities for wind and PV, and the transmission grid within renewable build-up pathways until 2030 and beyond. To simulate the Vietnamese power system and its generation from renewable sources, we use highly spatially and temporally resolved historical weather and load data and the open source modelling toolbox Python for Power System Analysis (PyPSA). We show that the highest potential of renewable generation for wind and PV is observed in southern Vietnam and discuss the resulting need for transmission grid extensions in dependency of the optimal pathway. Furthermore, we show that the smoothing effect of wind power has several considerable beneficial effects and that the Vietnamese hydro power potential can be efficiently used to provide balancing opportunities. This work is part of the R&D Project "Analysis of the Large Scale Integration of Renewable Power into the Future Vietnamese Power System" (GIZ, 2016-2018).

46 CFR 111.10-4 - Power requirements, generating sources.

Science.gov (United States)

2010-10-01

... ELECTRIC SYSTEMS-GENERAL REQUIREMENTS Power Supply § 111.10-4 Power requirements, generating sources. (a) The aggregate capacity of the electric ship's service generating sources required in § 111.10-3 must... or sources must be sufficient to supply those services necessary to provide normal operational...

Sources of the wind power stations

International Nuclear Information System (INIS)

Chudivani, J.; Huettner, L.

2012-01-01

The paper deals with problems of the wind power stations. Describes the basic properties of wind energy. Shows and describes the different types of electrical machines used as a source of electricity in the wind power stations. Shows magnetic fields synchronous generator with salient poles and permanent magnets in the program FEMM. Describes methods for assessing of reversing the effects of the wind power stations on the distribution network. (Authors)

The effect of 10 days of intermittent fasting on Wingate anaerobic power and prolonged high-intensity time-to-exhaustion cycling performance.

Science.gov (United States)

Naharudin, Mohamed Nashrudin Bin; Yusof, Ashril

2018-06-01

Many physically active individuals have undertaken intermittent fasting to reduce their daily caloric intake. However, abstaining from meals for a specific length of time may lead to the acute disturbance of highly carbohydrate-dependent exercise performance. The purpose of this study was to observe the effect of 10 days of intermittent fasting on high-intensity type exercises, Wingate anaerobic (WT) and prolonged high-intensity time-to-exhaustion (HIT) cycling test. Twenty participants were randomised into an intermittent fasting (FAS) and a control group (CON). One day after baseline data collection on Day-0 where participants consumed their recommended daily caloric intake (FAS = 2500 ± 143 kcal day -1 ; CON = 2492 ± 20 kcal day -1 ) served over a course of five meals, the FAS group consumed only four meals where 40% was restricted by the omission of lunch (FAS = 1500 ± 55 kcal day -1 ). This diet was then continued for 10 days. Data on exercise performance and other dependent variables were collected on Day-2, -4, -6, -8 and -10. A reduction in WT power in the FAS group was observed on Day-2 (821.74 ± 66.07 W) compared to Day-0 (847.63 ± 95.94 W) with a moderate effect size (p < .05, ES = 0.4), while HIT time-to-exhaustion performance declined over the 10 days with a trend of recovery from a large to a minimum effect size (p < .05, ES = 0.8-0.3). Body weight and triglyceride were consistently reduced in the FAS group (p < .01). The present study suggests that intermittent fasting must exceed 10 days to ensure that high-intensity performance does not deteriorate because this length of time seems to be required for effective adaptation to the new dietary regimen.

Consensus for linear multi-agent system with intermittent information transmissions using the time-scale theory

Science.gov (United States)

Taousser, Fatima; Defoort, Michael; Djemai, Mohamed

2016-01-01

This paper investigates the consensus problem for linear multi-agent system with fixed communication topology in the presence of intermittent communication using the time-scale theory. Since each agent can only obtain relative local information intermittently, the proposed consensus algorithm is based on a discontinuous local interaction rule. The interaction among agents happens at a disjoint set of continuous-time intervals. The closed-loop multi-agent system can be represented using mixed linear continuous-time and linear discrete-time models due to intermittent information transmissions. The time-scale theory provides a powerful tool to combine continuous-time and discrete-time cases and study the consensus protocol under a unified framework. Using this theory, some conditions are derived to achieve exponential consensus under intermittent information transmissions. Simulations are performed to validate the theoretical results.

Power conditioning system for energy sources

Science.gov (United States)

Mazumder, Sudip K [Chicago, IL; Burra, Rajni K [Chicago, IL; Acharya, Kaustuva [Chicago, IL

2008-05-13

Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

Multidimensional intermittency in hadronic collisions

International Nuclear Information System (INIS)

Pan, J.; Hwa, R.C.

1992-06-01

The study of intermittency in high-energy hadronic collisions by the Monte Carlo code ECCO is extended to 3-dimensional phase space. Strong intermittency is found in agreement with the data. Fluctuation in the impact parameter is responsible for the intermittency in lnp T , and the transverse-momentum conservation leads to negative intermittency slopes in the azimuthal angle φ. The Ochs-Wosiek plots are linear in all dimensions having universal slopes. An exponent ν = 1.448 emerges to characterize multiparticle production in pp collisions. The properties of G moments are also examined, and the fractal dimensions determined

Expected Future Conditions for Secure Power Operation with Large Scale of RES Integration

International Nuclear Information System (INIS)

Majstrovic, G.; Majstrovic, M.; Sutlovic, E.

2015-01-01

EU energy strategy is strongly focused on the large scale integration of renewable energy sources. The most dominant part here is taken by variable sources - wind power plants. Grid integration of intermittent sources along with keeping the system stable and secure is one of the biggest challenges for the TSOs. This part is often neglected by the energy policy makers, so this paper deals with expected future conditions for secure power system operation with large scale wind integration. It gives an overview of expected wind integration development in EU, as well as expected P/f regulation and control needs. The paper is concluded with several recommendations. (author).

Investigation of intermittency in simulated and experimental turbulence data by wavelet analysis

International Nuclear Information System (INIS)

Mahdizadeh, N.; Ramisch, M.; Stroth, U.; Lechte, C.; Scott, B.D.

2004-01-01

Turbulent transport in magnetized plasmas has an intermittent nature. Peaked probability density functions and a 1/frequency decay of the power spectra have been interpreted as signs of self-organized criticality generated, similar to a sand pile, by the critical gradients of ion- (ITG) or electron-temperature-gradient (ETG) driven instabilities. In order to investigate the degree of intermittency in toroidally confined plasmas in the absence of critical pressure or temperature gradients, data from the drift-Alfven-wave turbulence code DALF3 [B. Scott, Plasma Phys. Controlled Fusion 39, 1635 (1997)], running with a fixed background pressure gradient, and from a weakly driven low-temperature plasma are analyzed. The intermittency is studied on different temporal scales, which are separated by a wavelet transform. Simulated and experimental data reproduce the results on intermittent transport found in fusion plasmas. It can therefore be expected that in fusion plasmas, too, a substantial fraction of the bursty nature of turbulent transport is not related to avalanches caused by a critical gradient as generated by ITG or ETG turbulence

Intermittency patterns in pp collisions at 360 GeV/c

International Nuclear Information System (INIS)

Singh, J.B.; Kohli, J.M.

1991-01-01

The intermittency effect has been observed in pp collisions at 360 GeV/c and the strength decreases with the increase in multiplicity. The low multiplicity events in pp data (n ch ≤ 8), anti pp collisions (n ch ≤ 15) at Collider energy and elementary interaction (e + e - , μp) samples have almost the same strength. Most likely, few sources seem to contribute at lower multiplications. The intermittency effect is less in pp data compared to e + e - data, however it is fairly strong as compared to nucleus data. The presently used hadronization models DPM, LUND and FRITIOF do not reproduce the results fully. (orig.)

Household Solar Photovoltaics: Supplier of Marginal Abatement, or Primary Source of Low-Emission Power?

Directory of Open Access Journals (Sweden)

Graham Palmer

2013-03-01

Full Text Available With declining system costs and assuming a short energy payback period, photovoltaics (PV should, at face value, be able to make a meaningful contribution to reducing the emission intensity of Australia’s electricity system. However, solar is an intermittent power source and households remain completely dependent on a “less than green” electricity grid for reliable electricity. Further, much of the energy impact of PV occurs outside of the conventional boundaries of PV life-cycle analyses (LCA. This paper examines these competing observations and explores the broader impacts of a high penetration of household PV using Melbourne, Victoria as a reference. It concludes that in a grid dominated by unsequestered coal and gas, PV provides a legitimate source of emission abatement at high, but declining costs, with the potential for network and peak demand support. It may be technically possible to integrate a high penetration of PV, but the economic and energy cost of accommodating high-penetration PV erodes much of the benefits. Future developments in PV, storage, and integration technologies may allow PV to take on a greater long term role, but in the time horizon usually discussed in climate policy, a large-scale expansion of household PV may hinder rather than assist deep cuts to the emission intensity of Australia’s electricity system.

High stabilized power sources for bending and quadrupole magnets of TRISTAN project

International Nuclear Information System (INIS)

Kumagai, Noritaka; Ogawa, Shin-ichi; Koseki, Shoichiro; Nagasaka, Saburo.

1984-01-01

In the power source exciting the electro-magnets for the electron ring of TRISTAN project being advanced in the National Laboratory for High Energy Physics, the performance as strict as 10 -4 is required for its long hour stability and pulsating rate of DC output current in order to maintain beam stably. For satisfying such specification, the structure of power source using a high accuracy current detector, an active filter and so on was adopted. In order to verify the performance of this power source, the trial manufacture was carried out independently, and the test combining with actual magnets was performed. As the results, it was confirmed that the power source had the sufficient performance about its output stability, pulsating rate, current-following property and so on. At present, the manufacture of 80 actual power sources is in progress. In this paper, the power source system and the results of performance test of the power source made for trial are reported. The power sources are divide into B power sources for exciting deflecting electro-magnets and Q power sources for exciting quadrupole electro-magnets. (Kako, I.)

Radioisotope Sources of Electric Power

Science.gov (United States)

1973-09-20

u) watt/cm-3 O) specific activity f) curia/watt (curie/a) a) half-life c) specific power output h) years (capacity) 1) days d) watt/p Polonium - 210 ...AD/A-001 210 RADIOISOTOPE SOURCES OF ELECTRIC POWER G. M. Fradkin, et al Army Foreign Science and Technology Center Charlottesville, Virginia 20...narticularlv for nurninn and irocess~ino of wastg.Sheatinc food , conversion of liruld oxtoner to des, and also for removal of imnurities and reula:tion

Power source roadmaps using bibliometrics and database tomography

International Nuclear Information System (INIS)

Kostoff, R.N.; Tshiteya, R.; Pfeil, K.M.; Humenik, J.A.; Karypis, G.

2005-01-01

Database Tomography (DT) is a textual database analysis system consisting of two major components: (1) algorithms for extracting multi-word phrase frequencies and phrase proximities (physical closeness of the multi-word technical phrases) from any type of large textual database, to augment (2) interpretative capabilities of the expert human analyst. DT was used to derive technical intelligence from a Power Sources database derived from the Science Citation Index. Phrase frequency analysis by the technical domain experts provided the pervasive technical themes of the Power Sources database, and the phrase proximity analysis provided the relationships among the pervasive technical themes. Bibliometric analysis of the Power Sources literature supplemented the DT results with author/journal/institution/country publication and citation data

Use of non-conventional energy sources for power generation

International Nuclear Information System (INIS)

Umapathaiah, R.; Sharma, N.D.

1999-01-01

India being a developing country, cannot afford to meet the power and energy demand only from conventional sources. Power generation can be augmented by using non-conventional energy sources. Sufficient importance must be given for recovery of energy from industrial/urban waste. Solar heating system must replace industrial and domestic sectors. Solar photovoltaic, biogas plant, biomass based gasified system must also be given sufficient place in energy sector. More thrust has to be given for generation of power by using sugar cane which is a perennial source

Power Line Communications for Smart Grid Applications

Directory of Open Access Journals (Sweden)

Lars Torsten Berger

2013-01-01

Full Text Available Power line communication, that is, using the electricity infrastructure for data transmission, is experiencing a renaissance in the context of Smart Grid. Smart Grid objectives include the integration of intermittent renewable energy sources into the electricity supply chain, securing reliable electricity delivery, and using the existing electrical infrastructure more efficiently. This paper surveys power line communications (PLCs in the context of Smart Grid. The specifications G3-PLC, PRIME, HomePlug Green PHY, and HomePlug AV2, and the standards IEEE 1901/1901.2 and ITU-T G.hn/G.hnem are discussed.

Multi-point observations of intermittency in the cusp regions

Directory of Open Access Journals (Sweden)

M. M. Echim

2007-08-01

Full Text Available In this paper we investigate the statistical properties of magnetic field fluctuations measured by the four Cluster spacecraft in the cusp and close to the interface with the magnetospheric lobes, magnetopause and magnetosheath. At lower altitudes along the outbound orbit of 26 February 2001, the magnetic field fluctuations recorded by all four spacecraft are random and their Probability Distribution Functions (PDFs are Gaussian at all scales. The flatness parameter, F – related to the kurtosis of the time series, is equal to 3. At higher altitudes, in the cusp and its vicinity, closer to the interface with the magnetopause and magnetosheath, the PDFs from all Cluster satellites are non-Gaussian and show a clear intermittent behavior at scales smaller than τ_G≈ 61 s (or 170 km. The flatness parameter increases to values greater than 3 for scales smaller than τ_G. A Haar wavelet transform enables the identification of the "events" that produce sudden variations of the magnetic field and of the scales that have most of the power. The LIM parameter (i.e. normalized wavelet power indicates that events for scales below 65 s are non-uniformly distributed throughout the cusp passage. PDFs, flatness and wavelet analysis show that at coarse-grained scales larger than τ_G the intermittency is absent in the cusp. Fluctuations of the magnetic energy observed during the same orbit in the magnetosheath show PDFs that tend toward a Gaussian at scales smaller than τ_G found in the cusp. The flatness analysis confirms the decreasing of τ_G from cusp to magnetosheath. Our analysis reveals the turbulent cusp as a transition region from a non-intermittent turbulent state inside the magnetosphere to an intermittent turbulent state in the magnetosheath that has statistical properties resembling the solar wind turbulence. The observed turbulent fluctuations in the cusp suggests a phenomenon of nonlinear

Statistical studies of powerful extragalactic radio sources

Energy Technology Data Exchange (ETDEWEB)

Macklin, J T

1981-01-01

This dissertation is mainly about the use of efficient statistical tests to study the properties of powerful extragalactic radio sources. Most of the analysis is based on subsets of a sample of 166 bright (3CR) sources selected at 178 MHz. The first chapter is introductory and it is followed by three on the misalignment and symmetry of double radio sources. The properties of nuclear components in extragalactic sources are discussed in the next chapter, using statistical tests which make efficient use of upper limits, often the only available information on the flux density from the nuclear component. Multifrequency observations of four 3CR sources are presented in the next chapter. The penultimate chapter is about the analysis of correlations involving more than two variables. The Spearman partial rank correlation coefficient is shown to be the most powerful test available which is based on non-parametric statistics. It is therefore used to study the dependences of the properties of sources on their size at constant redshift, and the results are interpreted in terms of source evolution. Correlations of source properties with luminosity and redshift are then examined.

Source driven breeding thermal power reactors

International Nuclear Information System (INIS)

Greenspan, E.; Ben-Gurion Univ. of the Negev, Beersheba

1978-03-01

The feasibility of fusion devices operating in the semi-catalyzed deuterium (SCD) mode and of high energy proton accelerators to provide the neutron sources for driving subcritical breeding light water power reactors is assessed. The assessment is done by studying the energy balance of the resulting source driven light water reactors (SDLWR) and comparing it with the energy balance of the reference light water hybrid reactors (LWHR) driven by a D-T neutron source (DT-LWHR). The conditions the non-DT neutron sources should satisfy in order to make the SDLWR viable power reactors are identified. It is found that in order for a SCD-LWHR to have the same overall efficiency as a DT-LWHR, the fusion energy gain of the SCD device should be at least one half that the DT device. The efficienct of ADLWRs using uranium targets is comparable with that of DT-LWHRs having a fusion energy gain of unity. Advantages and disadvantages of the DT-LWHR, SCD-LWHR and ADLWR are discussed. (aurthor)

Metabolic Effects of Intermittent Fasting.

Science.gov (United States)

Patterson, Ruth E; Sears, Dorothy D

2017-08-21

The objective of this review is to provide an overview of intermittent fasting regimens, summarize the evidence on the health benefits of intermittent fasting, and discuss physiological mechanisms by which intermittent fasting might lead to improved health outcomes. A MEDLINE search was performed using PubMed and the terms "intermittent fasting," "fasting," "time-restricted feeding," and "food timing." Modified fasting regimens appear to promote weight loss and may improve metabolic health. Several lines of evidence also support the hypothesis that eating patterns that reduce or eliminate nighttime eating and prolong nightly fasting intervals may result in sustained improvements in human health. Intermittent fasting regimens are hypothesized to influence metabolic regulation via effects on (a) circadian biology, (b) the gut microbiome, and (c) modifiable lifestyle behaviors, such as sleep. If proven to be efficacious, these eating regimens offer promising nonpharmacological approaches to improving health at the population level, with multiple public health benefits.

Events as Power Source: Wireless Sustainable Corrosion Monitoring

Directory of Open Access Journals (Sweden)

Guodong Sun

2013-12-01

Full Text Available This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source, which monitors the corrosion events in reinforced concrete (RC structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

Events as power source: wireless sustainable corrosion monitoring.

Science.gov (United States)

Sun, Guodong; Qiao, Guofu; Zhao, Lin; Chen, Zhibo

2013-12-17

This study presents and implements a corrosion-monitoring wireless sensor platform, EPS (Events as Power Source), which monitors the corrosion events in reinforced concrete (RC) structures, while being powered by the micro-energy released from the corrosion process. In EPS, the proposed corrosion-sensing device serves both as the signal source for identifying corrosion and as the power source for driving the sensor mote, because the corrosion process (event) releases electric energy; this is a novel idea proposed by this study. For accumulating the micro-corrosion energy, we integrate EPS with a COTS (Commercial Off-The-Shelf) energy-harvesting chip that recharges a supercapacitor. In particular, this study designs automatic energy management and adaptive transmitted power control polices to efficiently use the constrained accumulated energy. Finally, a set of preliminary experiments based on concrete pore solution are conducted to evaluate the feasibility and the efficacy of EPS.

Unattended power sources for remote, harsh environments

International Nuclear Information System (INIS)

Lamp, T.R.; Donovan, B.D.

1994-01-01

Forest fires that have endangered remote US Air Force sites equipped with radioisotope thermoelectric generators (RTGs) has prompted the assessment of power generating systems as substitutes for RTGs in small scale (10--120 watt) applications. A team of scientists and engineers of the US Air Forces' Wright Laboratory conducted an assessment of electrical power technologies for use by the Air Force in remote, harsh environments. The surprisingly high logistic costs of operating fossil fuel generators resulted in the extension of the assessment to non-RTG sites. The candidate power sources must operate unattended for long periods at a high level of operations reliability. Selection of the optimum power generation technology is complicated and heavily driven by the severe operating environment compounded by the remoteness of the location. It is these site-related characteristics, more than any other, that drive the selection of a safe and economical power source for Arctic applications. A number of proven power generation technologies were evaluated. The assessment concluded that continued use of the RTGs is clearly the safest, most reliable, and most economical approach to supplying electrical power for remote, difficult to access locations

Impedance-Source Networks for Electric Power Conversion Part II

DEFF Research Database (Denmark)

Siwakoti, Yam P.; Peng, Fang Zheng; Blaabjerg, Frede

2015-01-01

Impedance-source networks cover the entire spectrum of electric power conversion applications (dc-dc, dc-ac, ac-dc, ac-ac) controlled and modulated by different modulation strategies to generate the desired dc or ac voltage and current at the output. A comprehensive review of various impedance......-source-network-based power converters has been covered in a previous paper and main topologies were discussed from an application point of view. Now Part II provides a comprehensive review of the most popular control and modulation strategies for impedance-source network-based power converters/inverters. These methods...

Compact portable electric power sources

Energy Technology Data Exchange (ETDEWEB)

Fry, D.N.; Holcomb, D.E.; Munro, J.K.; Oakes, L.C.; Matson, M.J.

1997-02-01

This report provides an overview of recent advances in portable electric power source (PEPS) technology and an assessment of emerging PEPS technologies that may meet US Special Operations Command`s (SOCOM) needs in the next 1--2- and 3--5-year time frames. The assessment was performed through a literature search and interviews with experts in various laboratories and companies. Nineteen PEPS technologies were reviewed and characterized as (1) PEPSs that meet SOCOM requirements; (2) PEPSs that could fulfill requirements for special field conditions and locations; (3) potentially high-payoff sources that require additional R and D; and (4) sources unlikely to meet present SOCOM requirements. 6 figs., 10 tabs.

EFFECTS OF INTERMITTENT EMISSION: NOISE INVENTORY FOR THE SCINTILLATING PULSAR B0834+06

International Nuclear Information System (INIS)

Gwinn, C. R.; Johnson, M. D.; Smirnova, T. V.; Stinebring, D. R.

2011-01-01

We compare signal and noise for observations of the scintillating pulsar B0834+06, using very long baseline interferometry and a single-dish spectrometer. Comparisons between instruments and with models suggest that amplitude variations of the pulsar strongly affect the amount and distribution of self-noise. We show that noise follows a quadratic polynomial with flux density, in spectral observations. Constant coefficients, indicative of background noise, agree well with expectation; whereas second-order coefficients, indicative of self-noise, are ∼3 times values expected for a pulsar with constant on-pulse flux density. We show that variations in flux density during the 10 s integration accounts for the discrepancy. In the secondary spectrum, ∼97% of spectral power lies within the pulsar's typical scintillation bandwidth and timescale; an extended scintillation arc contains ∼3%. For a pulsar with constant on-pulse flux density, noise in the dynamic spectrum will appear as a uniformly distributed background in the secondary spectrum. We find that this uniform noise background contains 95% of noise in the dynamic spectrum for interferometric observations; but only 35% of noise in the dynamic spectrum for single-dish observations. Receiver and sky dominate noise for our interferometric observations, whereas self-noise dominates for single-dish. We suggest that intermittent emission by the pulsar, on timescales <300 μs, concentrates self-noise near the origin in the secondary spectrum, by correlating noise over the dynamic spectrum. We suggest that intermittency sets fundamental limits on pulsar astrometry or timing. Accounting of noise may provide means for detection of intermittent sources, when effects of propagation are unknown or impractical to invert.

Modelling the energy future of Switzerland after the phase out of nuclear power plants

Science.gov (United States)

Diaz, Paula; Van Vliet, Oscar

2015-04-01

In September 2013, the Swiss Federal Office of Energy (SFOE) published the final report of the proposed measures in the context of the Energy Strategy 2050 (ES2050). The ES2050 draws an energy scenario where the nuclear must be substituted by alternative sources. This implies a fundamental change in the energy system that has already been questioned by experts, e.g. [Piot, 2014]. Therefore, we must analyse in depth the technical implications of change in the Swiss energy mix from a robust baseload power such as nuclear, to an electricity mix where intermittent sources account for higher rates. Accomplishing the ES2050 imply difficult challenges, since nowadays nuclear power is the second most consumed energy source in Switzerland. According to the SFOE, nuclear accounts for a 23.3% of the gross production, only surpassed by crude oil products (43.3%). Hydropower is the third source more consumed, representing approximately the half of the nuclear (12.2%). Considering that Switzerland has almost reached the maximum of its hydropower capacity, renewables are more likely to be the alternative when the nuclear phase out takes place. Hence, solar and wind power will play an important role in the future Swiss energy mix, even though currently new renewables account for only 1.9% of the gross energy consumption. In this study we look for realistic and efficient combinations of energy resources to substitute nuclear power. Energy modelling is a powerful tool to design an energy system with high energy security that avoids problems of intermittency [Mathiesen & Lund, 2009]. In Switzerland, energy modelling has been used by the government [Abt et. al., 2012] and also has significant relevance in academia [Mathys, 2012]. Nevertheless, we detected a gap in the study of the security in energy scenarios [Busser, 2013]. This study examines the future electricity production of Switzerland using Calliope, a multi-scale energy systems model, developed at Imperial College, London and

Integrated societal risk assessment framework for nuclear power and renewable energy sources

International Nuclear Information System (INIS)

Lee, Sang Hun; Kang, Hyun Gook

2015-01-01

Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh) of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources

Integrated societal risk assessment framework for nuclear power and renewable energy sources

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Hun; Kang, Hyun Gook [Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of)

2015-06-15

Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh) of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources.

Towards an intermittency-friendly energy system: Comparing electric boilers and heat pumps in distributed cogeneration

International Nuclear Information System (INIS)

Blarke, Morten B.

2012-01-01

Highlights: ► We propose an “intermittency-friendly” energy system design. ► We compare intermittency-friendly concepts in distributed cogeneration. ► We investigate a new concept involving a heat pump and intermediate cold storage. ► We find significant improvements in operational intermittency-friendliness. ► Well-designed heat pump concepts are more cost-effective than electric boilers. -- Abstract: Distributed cogeneration has played a key role in the implementation of sustainable energy policies for three decades. However, increasing penetration levels of intermittent renewables is challenging that position. The paradigmatic case of West Denmark indicates that distributed operators are capitulating as wind power penetration levels are moving above 25%; some operators are retiring cogeneration units entirely, while other operators are making way for heat-only boilers. This development is jeopardizing the system-wide energy, economic, and environmental benefits that distributed cogeneration still has to offer. The solution is for distributed operators to adapt their technology and operational strategies to achieve a better co-existence between cogeneration and wind power. Four options for doing so are analysed including a new concept that integrates a high pressure compression heat pump using low-temperature heat recovered from flue gasses in combination with an intermediate cold storage, which enables the independent operation of heat pump and cogenerator. It is found that an electric boiler provides consistent improvements in the intermittency-friendliness of distributed cogeneration. However, well-designed heat pump concepts are more cost-effective than electric boilers, and in future markets where the gas/electricity price ratio is likely to increase, compression heat pumps in combination with intermediate thermal storages represent a superior potential for combining an intermittency-friendly pattern of operation with the efficient use of

Intermittent magnetic reconnection in TS-3 merging experiment

International Nuclear Information System (INIS)

Ono, Y.; Hayashi, Y.; Ii, T.; Tanabe, H.; Ito, S.; Kuwahata, A.; Ito, T.; Kamino, Y.; Yamada, T.; Inomoto, M.

2011-01-01

Ejection of current sheet with plasma mass causes impulsive and intermittent magnetic reconnection in the TS-3 spherical tokamak (ST) merging experiment. Under high guide toroidal field, the sheet resistivity is almost classical due to the sheet thickness much longer than the ion gyroradius. Large inflow flux and low current-sheet resistivity result in flux and plasma pileup followed by rapid growth of the current sheet. When the pileup exceeds a critical limit, the sheet is ejected mechanically from the squeezed X-point area. The reconnection (outflow) speed is slow during the flux/plasma pileup and is fast during the ejection, suggesting that intermittent reconnection similar to the solar flare increases the averaged reconnection speed. These transient effects enable the merging tokamaks to have the fast reconnection as well as the high-power reconnection heating, even when their current-sheet resistivity is low under high guide field.

Power Management for Energy Systems

DEFF Research Database (Denmark)

Hovgaard, Tobias Gybel

In this thesis, we consider the control of two different industrial applications that belong at either end of the electricity grid; a power consumer in the form of a commercial refrigeration system, and wind turbines for power production. Our primary studies deal with economic model predictive...... penetration of renewable, fossil-free energy sources such as solar and wind power. To facilitate such intermittent power producers, we must not only control the production of electricity, but also the consumption, in an ecient and exible manner. By enabling the use of thermal energy storage in supermarkets...... of temperature dependent efficiencies in the refrigeration cycle. -Nonlinear economic MPC with uncertain predictions and the implementation of very simple predictors that use entirely historical data of, e.g., electricity prices and outdoor temperatures. Economic MPC for wind turbines, including -Optimal steady...

Visuo-manual tracking: does intermittent control with aperiodic sampling explain linear power and non-linear remnant without sensorimotor noise?

Science.gov (United States)

Gollee, Henrik; Gawthrop, Peter J; Lakie, Martin; Loram, Ian D

2017-11-01

ways) manually controlled two systems (1st and 2nd order) subject to a periodic multi-sine disturbance. Joystick power was analysed using three models, continuous-linear-control (CC), continuous-linear-control with calculated noise spectrum (CCN), and intermittent control with aperiodic sampling triggered by prediction error thresholds (IC). Unlike the linear mechanism, the intermittent control mechanism explained the majority of total power (linear and remnant) (77-87% vs. 8-48%, IC vs. CC). Between conditions, IC used thresholds and distributions of open loop intervals consistent with, respectively, instructions and previous measured, model independent values; whereas CCN required changes in noise spectrum deviating from broadband, signal dependent noise. We conclude that manual tracking uses open loop predictive control with aperiodic sampling. Because aperiodic sampling is inherent to serial decision making within previously identified, specific frontal, striatal and parietal networks we suggest that these structures are intimately involved in visuo-manual tracking. © 2017 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society.

Market power and technological bias in electricity generation markets

International Nuclear Information System (INIS)

Twomey, Paul; Neuhoff, Karsten

2005-01-01

It is difficult or very costly to avoid all market power in electricity markets. A recurring response is that a limited amount of market power is accepted with the justification that it is necessary to produce revenues to cover some of the fixed costs. It is assumed that all market participants benefit equally from the increased prices. However, this assumption is not satisfied if different production technologies are used. We assess the case of a generation mix of conventional generation and intermittent generation with exogenously varying production levels. If all output is sold in the spot market, then intermittent generation benefits less from market power than conventional generation. If forward contracts or option contracts are signed, then market power might be reduced but the bias against returns to intermittent generators persists. Thus allowing some level of market power as a means of encouraging investment in new generation may result in a bias against intermittent technologies or increase the costs of strategic deployment to achieve renewable quotas. (Author)

Towards an intermittency-friendly energy system

DEFF Research Database (Denmark)

Blarke, Morten

2012-01-01

Distributed cogeneration has played a key role in the implementation of sustainable energy policies for three decades. However, increasing penetration levels of intermittent renewables is challenging that position. The paradigmatic case of West Denmark indicates that distributed operators...... are capitulating as wind power penetration levels are moving above 25%; some operators are retiring cogeneration units entirely, while other operators are making way for heat-only boilers. This development is jeopardizing the system-wide energy, economic, and environmental benefits that distributed cogeneration...... still has to offer. The solution is for distributed operators to adapt their technology and operational strategies to achieve a better co-existence between cogeneration and wind power. Four options for doing so are analysed including a new concept that integrates a high pressure compression heat pump...

Portable Thermoelectric Power Generator Coupled with Phase Change Material

Directory of Open Access Journals (Sweden)

Lim Chong C.

2014-07-01

Full Text Available Solar is the intermittent source of renewable energy and all thermal solar systems having a setback on non-functioning during the night and cloudy environment. This paper presents alternative solution for power generation using thermoelectric which is the direct conversion of temperature gradient of hot side and cold side of thermoelectric material to electric voltage. Phase change material with latent heat effect would help to prolong the temperature gradient across thermoelectric material for power generation. Besides, the concept of portability will enable different power source like solar, wasted heat from air conditioner, refrigerator, stove etc, i.e. to create temperature different on thermoelectric material for power generation. Furthermore, thermoelectric will generate direct current which is used by all the gadgets like Smartphone, tablet, laptop etc. The portable concept of renewable energy will encourage the direct usage of renewable energy for portable gadgets. The working principle and design of portable thermoelectric power generator coupled with phase change material is presented in this paper.

Integrated societal risk assessment framework for nuclear power and renewable energy sources

Directory of Open Access Journals (Sweden)

Sang Hun Lee

2015-06-01

Full Text Available Recently, the estimation of the social cost of energy sources has been emphasized as various novel energy options become feasible in addition to conventional ones. In particular, the social cost of introducing measures to protect power-distribution systems from power-source instability and the cost of accident-risk response for various power sources must be investigated. To account for these risk factors, an integrated societal risk assessment framework, based on power-uncertainty analysis and accident-consequence analysis, is proposed. In this study, we applied the proposed framework to nuclear power plants, solar photovoltaic systems, and wind-turbine generators. The required capacity of gas-turbine power plants to be used as backup power facilities to compensate for fluctuations in the power output from the main power source was estimated based on the performance indicators of each power source. The average individual health risk per terawatt-hours (TWh of electricity produced by each power source was quantitatively estimated by assessing accident frequency and the consequences of specific accident scenarios based on the probabilistic risk assessment methodology. This study is expected to provide insight into integrated societal risk analysis, and can be used to estimate the social cost of various power sources.

Scaling law of diffusivity generated by a noisy telegraph signal with fractal intermittency

International Nuclear Information System (INIS)

Paradisi, Paolo; Allegrini, Paolo

2015-01-01

In many complex systems the non-linear cooperative dynamics determine the emergence of self-organized, metastable, structures that are associated with a birth–death process of cooperation. This is found to be described by a renewal point process, i.e., a sequence of crucial birth–death events corresponding to transitions among states that are faster than the typical long-life time of the metastable states. Metastable states are highly correlated, but the occurrence of crucial events is typically associated with a fast memory drop, which is the reason for the renewal condition. Consequently, these complex systems display a power-law decay and, thus, a long-range or scale-free behavior, in both time correlations and distribution of inter-event times, i.e., fractal intermittency. The emergence of fractal intermittency is then a signature of complexity. However, the scaling features of complex systems are, in general, affected by the presence of added white or short-term noise. This has been found also for fractal intermittency. In this work, after a brief review on metastability and noise in complex systems, we discuss the emerging paradigm of Temporal Complexity. Then, we propose a model of noisy fractal intermittency, where noise is interpreted as a renewal Poisson process with event rate r_p. We show that the presence of Poisson noise causes the emergence of a normal diffusion scaling in the long-time range of diffusion generated by a telegraph signal driven by noisy fractal intermittency. We analytically derive the scaling law of the long-time normal diffusivity coefficient. We find the surprising result that this long-time normal diffusivity depends not only on the Poisson event rate, but also on the parameters of the complex component of the signal: the power exponent μ of the inter-event time distribution, denoted as complexity index, and the time scale T needed to reach the asymptotic power-law behavior marking the emergence of complexity. In particular

Reactor Core Design and Analysis for a Micronuclear Power Source

Directory of Open Access Journals (Sweden)

Hao Sun

2018-03-01

Full Text Available Underwater vehicle is designed to ensure the security of country sea boundary, providing harsh requirements for its power system design. Conventional power sources, such as battery and Stirling engine, are featured with low power and short lifetime. Micronuclear reactor power source featured with higher power density and longer lifetime would strongly meet the demands of unmanned underwater vehicle power system. In this paper, a 2.4 MWt lithium heat pipe cooled reactor core is designed for micronuclear power source, which can be applied for underwater vehicles. The core features with small volume, high power density, long lifetime, and low noise level. Uranium nitride fuel with 70% enrichment and lithium heat pipes are adopted in the core. The reactivity is controlled by six control drums with B4C neutron absorber. Monte Carlo code MCNP is used for calculating the power distribution, characteristics of reactivity feedback, and core criticality safety. A code MCORE coupling MCNP and ORIGEN is used to analyze the burnup characteristics of the designed core. The results show that the core life is 14 years, and the core parameters satisfy the safety requirements. This work provides reference to the design and application of the micronuclear power source.

Life cycle cost analysis of wind power considering stochastic uncertainties

International Nuclear Information System (INIS)

Li, Chiao-Ting; Peng, Huei; Sun, Jing

2014-01-01

This paper presents a long-term cost analysis of wind power and compares its competitiveness to non-renewable generating technologies. The analysis considers several important attributes related to wind intermittency that are sometimes ignored in traditional generation planning or LCOE (levelized cost of energy) studies, including the need for more nameplate capacity due to intermittency, hourly fluctuations in wind outputs and cost for reserves. The competitiveness of wind power is assessed by evaluating four scenarios: 1) adding natural gas generating capacity to the power grid; 2) adding coal generating capacity to the power grid; 3) adding wind capacity to the power grid; and, 4) adding wind capacity and energy storage to the power grid where an energy storage device is used to cover wind intermittency. A case study in the state of Michigan is presented to demonstrate the use of the proposed methodology, in which a time horizon from 2010 to 2040 is considered. The results show that wind energy will still be more expensive than natural gas power plants in the next three decades, but will be cheaper than coal capacities if wind intermittency is mitigated. Furthermore, if the costs of carbon emissions and environmental externalities are considered, wind generation will be a competitive option for grid capacity expansion. - Highlights: • The competitiveness of wind power is analyzed via life cycle cost analysis. • Wind intermittency and reserve costs are explicitly considered in the analysis. • Results show that wind is still more expensive than natural gas power plants. • Wind can be cheaper than coal capacities if wind intermittency is mitigated. • Wind will be competitive if costs of carbon emissions are considered

Model predictive control for Z-source power converter

DEFF Research Database (Denmark)

Mo, W.; Loh, P.C.; Blaabjerg, Frede

2011-01-01

This paper presents Model Predictive Control (MPC) of impedance-source (commonly known as Z-source) power converter. Output voltage control and current control for Z-source inverter are analyzed and simulated. With MPC's ability of multi- system variables regulation, load current and voltage...

WWER type reactors used as multipurpose nuclear power sources

International Nuclear Information System (INIS)

Fiala, J.; Mulak, J.

1976-01-01

Safety aspects are assessed of the siting of nuclear power installations in the vicinity of large housing estates and in areas with a high population density, mainly the aspect of the liquidation of the consequences of the maximum credible accident, i.e., the transversal rupture of the primary coolant circuit. The application of WWER type reactors as multipurpose nuclear power sources in Czechoslovakia is justified. It is shown that such a multipurpose nuclear power source differs from a purely condensation nuclear power plant mainly in the design of the secondary stage. The possibilities of such projects are indicated with a view to power and heat operation. (F.M.)

Saturable reactor-controlled power supply system for TCT/TFTR neutral beam sources

International Nuclear Information System (INIS)

Baker, W.R.; Hopkins, D.B.; Dexter, W.L.; Kuenning, R.W.; Smith, B.J.

1975-11-01

Each neutral beam source requires one major power supply, the acceleration supply, and four auxiliary power supplies. The power supplies are designed to permit independent interruption of current to any source and crowbarring within 20 μsec, in the event of a source spark, while not disturbing the normal pulsing of all other adjacent sources. The sources are described

The reliability and validity of fatigue measures during short-duration maximal-intensity intermittent cycling.

Science.gov (United States)

Glaister, Mark; Stone, Michael H; Stewart, Andrew M; Hughes, Michael; Moir, Gavin L

2004-08-01

The purpose of the present study was to assess the reliability and validity of fatigue measures, as derived from 4 separate formulae, during tests of repeat sprint ability. On separate days over a 3-week period, 2 groups of 7 recreationally active men completed 6 trials of 1 of 2 maximal (20 x 5 seconds) intermittent cycling tests with contrasting recovery periods (10 or 30 seconds). All trials were conducted on a friction-braked cycle ergometer, and fatigue scores were derived from measures of mean power output for each sprint. Apart from formula 1, which calculated fatigue from the percentage difference in mean power output between the first and last sprint, all remaining formulae produced fatigue scores that showed a reasonably good level of test-retest reliability in both intermittent test protocols (intraclass correlation range: 0.78-0.86; 95% likely range of true values: 0.54-0.97). Although between-protocol differences in the magnitude of the fatigue scores suggested good construct validity, within-protocol differences highlighted limitations with each formula. Overall, the results support the use of the percentage decrement score as the most valid and reliable measure of fatigue during brief maximal intermittent work.

Power source device for thermonuclear device

International Nuclear Information System (INIS)

Ozaki, Akira.

1992-01-01

The present invention provides a small sized and economical power source device for a thermonuclear device. That is, the device comprises a conversion device having a rated power determined by a power required during a plasma current excitation period and a conversion device having a rated power determined by a power required during a plasma current maintaining period, connected in series to each other. Then, for the former conversion device, power is supplied from an electric power generator and, for the latter, power is supplied from a power system. With such a constitution, during the plasma electric current maintaining period for substantially continuous operation, it is possible to conduct bypassing paired operation for the former conversion device while the electric power generator is put under no load. Further, since a short period rated power may be suffice for the former conversion device and the electric power generator having the great rated power required for the plasma electric current excitation period, they can be reduced in the size and made economical. On the other hand, since the power required for the plasma current maintaining period is relatively small, the capacity of the continuous rated conversion device may be small, and the power can be received from the power system. (I.S.)

Powerful warm infrared sources in early-type galaxies

International Nuclear Information System (INIS)

Dressel, L.L.

1988-01-01

IRAS far-infrared sources have been identified with 129 S0, Sa, Sb, and Sc galaxies in a statistically complete sample of 738 galaxies brighter than 14.5 mag and smaller than 4.0 arcmin. In most cases, the far-IR colors and the ratios of far-IR flux to radio flux density are those of normal galactic disks and/or starbursts. The most powerful far-IR sources in S0 and Sa galaxies are just as powerful as the strongest far-IR sources in Sb and Sc galaxies. Bright-IR sources in S0 and Sa galaxies are warm; those in Sc galaxies are cool. Sb galaxies have both warm and cool IR sources. Bright warm IR sources occur much more frequently in barred galaxies than in galaxies without bars for types S0, Sa, and Sb. Bright, cool IR sources are found with increasing frequency along the Hubble sequence, regardless of the presence or absence of a bar. At least some S0 galaxies with warm, bright IR sources have peculiar morphologies and ambiguous classifications. 22 references

Hybrid wind power balance control strategy using thermal power, hydro power and flow batteries

OpenAIRE

Gelažanskas, Linas; Baranauskas, Audrius; Gamage, Kelum A.A.; Ažubalis, Mindaugas

2016-01-01

The increased number of renewable power plants pose threat to power system balance. Their intermittent nature makes it very difficult to predict power output, thus either additional reserve power plants or new storage and control technologies are required. Traditional spinning reserve cannot fully compensate sudden changes in renewable energy power generation. Using new storage technologies such as flow batteries, it is feasible to balance the variations in power and voltage within very short...

Randomized, controlled trial comparing synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in preterm infants.

Science.gov (United States)

Reyes, Zenaida C; Claure, Nelson; Tauscher, Markus K; D'Ugard, Carmen; Vanbuskirk, Silvia; Bancalari, Eduardo

2006-10-01

Prolonged mechanical ventilation is associated with lung injury in preterm infants. In these infants, weaning from synchronized intermittent mandatory ventilation may be delayed by their inability to cope with increased respiratory loads. The addition of pressure support to synchronized intermittent mandatory ventilation can offset these loads and may facilitate weaning. The purpose of this work was to compare synchronized intermittent mandatory ventilation and synchronized intermittent mandatory ventilation plus pressure support in weaning from mechanical ventilation and the duration of supplemental oxygen dependency in preterm infants with respiratory failure. Preterm infants weighing 500 to 1000 g at birth who required mechanical ventilation during the first postnatal week were randomly assigned to synchronized intermittent mandatory ventilation or synchronized intermittent mandatory ventilation plus pressure support. In both groups, weaning followed a set protocol during the first 28 days. Outcomes were assessed during the first 28 days and until discharge or death. There were 107 infants enrolled (53 synchronized intermittent mandatory ventilation plus pressure support and 54 synchronized intermittent mandatory ventilation). Demographic and perinatal data, mortality, and morbidity did not differ between groups. During the first 28 days, infants in the synchronized intermittent mandatory ventilation plus pressure support group reached minimal ventilator settings and were extubated earlier than infants in the synchronized intermittent mandatory ventilation group. Total duration of mechanical ventilation, duration of oxygen dependency, and oxygen need at 36 weeks' postmenstrual age alone or combined with death did not differ between groups. However, infants in synchronized intermittent mandatory ventilation plus pressure support within the 700- to 1000-g birth weight strata had a shorter oxygen dependency. The results of this study suggest that the addition of

Renewable energies: the cost of intermittency

International Nuclear Information System (INIS)

Crassous, Renaud; Roques, Fabien

2013-01-01

The authors indicate the different adaptations which will be required for the electric system to cope with the intermittency of solar and wind energy production, and propose an approximate assessment of the associated costs. Different types of adaptation are addressed: secure production in case of absence of wind or sun (electricity imports, construction of additional power stations), use of more flexible production means (gas turbines), grid extensions (connection to offshore production sites, routing of production one part of the country to the other). They think that beyond a 20 per cent share for renewable energies, these costs could rapidly increase

Nonsafety loads on glass 1E power sources, revisited

International Nuclear Information System (INIS)

Lewin, J.

1980-01-01

The supply of some nonsafety loads from class 1E power sources is allowed by industry standards (IEEE Standards 308 and 384) and by US Nuclear Regulatory Commission Regulatory Guides 1.32 and 1.75. This has been questioned as a possible source of degradation of the class 1E system, and this power deals with assessment of the effects of this practice on the reliability of the power supply for engineered safety features (ESF) systems

Experimental progress on virtual-cathode very high power microwave source development

International Nuclear Information System (INIS)

Fazio, M.V.; Hoeberling, R.F.

1987-01-01

The evolution of rf accelerator technology toward high-power, high-current, low-emittance beams produces an ever-increasing demand for efficient, very high power microwave sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing electron sources can produce microwave powers at the gigawatt level and have demonstrated operation from 800 MHz to 40 GHz. Pulse length appears to be limited by electron-beam diode closure, and reflexing electron devices have been operated in a repetitively pulsed mode. An experiment is under way to investigate concepts to stabilize the frequency of the virtual cathode source. If one can successfully frequency and phase lock this source to an external signal, then this source can operate as a very high power microwave amplifier making it practical for accelerator applications. The progress on an experiment to test these concepts will be discussed

Hovering and intermittent flight in birds

International Nuclear Information System (INIS)

Tobalske, Bret W

2010-01-01

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound (∼0.3 kg) and small birds with rounded wings do not use intermittent glides.

Hovering and intermittent flight in birds

Energy Technology Data Exchange (ETDEWEB)

Tobalske, Bret W, E-mail: bret.tobalske@mso.umt.ed [Field Research Station at Fort Missoula, Division of Biological Sciences, University of Montana, Missoula, MT 59812 (United States)

2010-12-15

Two styles of bird locomotion, hovering and intermittent flight, have great potential to inform future development of autonomous flying vehicles. Hummingbirds are the smallest flying vertebrates, and they are the only birds that can sustain hovering. Their ability to hover is due to their small size, high wingbeat frequency, relatively large margin of mass-specific power available for flight and a suite of anatomical features that include proportionally massive major flight muscles (pectoralis and supracoracoideus) and wing anatomy that enables them to leave their wings extended yet turned over (supinated) during upstroke so that they can generate lift to support their weight. Hummingbirds generate three times more lift during downstroke compared with upstroke, with the disparity due to wing twist during upstroke. Much like insects, hummingbirds exploit unsteady mechanisms during hovering including delayed stall during wing translation that is manifest as a leading-edge vortex (LEV) on the wing and rotational circulation at the end of each half stroke. Intermittent flight is common in small- and medium-sized birds and consists of pauses during which the wings are flexed (bound) or extended (glide). Flap-bounding appears to be an energy-saving style when flying relatively fast, with the production of lift by the body and tail critical to this saving. Flap-gliding is thought to be less costly than continuous flapping during flight at most speeds. Some species are known to shift from flap-gliding at slow speeds to flap-bounding at fast speeds, but there is an upper size limit for the ability to bound ({approx}0.3 kg) and small birds with rounded wings do not use intermittent glides.

Intermittency in 197Au fragmentation

International Nuclear Information System (INIS)

Dabrowska, A.; Holynski, R.; Olszewski, A.; Szarska, M.; Wilczynska, B.; Wolter, W.; Wosiek, B.; Cherry, M.L.; Deines-Jones, P.; Jones, W.V.; Sengupta, K.; Wefel, B.

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs

Power Sources for Micro-Autonomous Vehicles- Challenges and Prospects

Science.gov (United States)

Narayan, S. R.; Kisor, A.; Valdez, T. I.; Manohara, H.

2009-01-01

Micro-autonomous vehicle systems are expected to have expanded role in military missions by providing full spectrum intelligence, surveillance and reconnaissance support on the battlefield, suppression of enemy defenses, and enabling co-operative (swarm-like) configurations. Of the numerous demanding requirements of autonomy, sensing, navigation, mobility, etc., meeting the requirement of mission duration or endurance is a very challenging one. This requirement is demanding because of the constraints of mass and volume that limit the quantity of energy that can be stored on-board. Energy is required for mobility, payload operation, information processing, and communication. Mobility requirements typically place an extraordinary demand on the specific energy (Wh/kg) and specific power (W/kg) of the power source; the actual distribution of the energy between mobility and other system functions could vary substantially with the mission type. The power requirements for continuous mobility can vary from 100-1000 W/kg depending on the terrain, ground speed and flight speed. Even with the power source accounting for 30% of the mass of the vehicle, the best of rechargeable batteries can provide only up to 1-2 hours of run-time for a continuous power demand at 100W/kg. In the case of micro-aerial vehicles with flight speed requirements in the range of 5-15 m s-1, the mission times rarely exceed 20 minutes [2]. Further, the power required during take-off and hover can be twice or thrice that needed for steady level flight, and thus the number and sequence of such events is also limited by the mass and size of the power source. For operations such as "perch and stare" or "silent watch" the power demand is often only a tenth of that required during continuous flight. Thus, variation in power demand during various phases of the mission importantly affects the power source selection.

Economic analysis of the need for advanced power sources

International Nuclear Information System (INIS)

Hardie, R.W.; Omberg, R.P.

1975-01-01

The purpose of this paper is to determine the economic need for an advanced power source, be it fusion, solar, or some other concept. However, calculations were also performed assuming abandonment of the LMFBR program, so breeder benefits are a by-product of this study. The model used was the ALPS linear programming system for forecasting optimum power growth patterns. Total power costs were calculated over a planning horizon from 1975 to 2041 and discounted at 7 1 / 2 percent. The benefit of a particular advanced power source is simply the reduction in total power cost resulting from its introduction. Since data concerning advanced power sources (APS) are speculative, parametric calculations varying introduction dates and capital costs about a hypothetical APS plant were performed. Calculations were also performed without the LMFBR to determine the effect of the breeder on the benefits of an advanced power source. Other data used in the study, such as the energy demand curve and uranium resource estimates, are given in the Appendix, and a list of the 11 power plants used in this study is given. Calculations were performed for APS introduction dates of 2001 and 2011. Estimates of APS capital costs included cases where it was assumed the costs were $50/kW and $25/kW higher than the LMFBR. In addition, cases where APS and LMFBR capital costs are identical were also considered. It is noted that the APS capital costs used in this study are not estimates of potential advanced power system plant costs, but were chosen to compute potential dollar benefits of advanced power systems under extremely optimistic assumptions. As a further example, all APS fuel cycle costs were assumed to be zero

Portable Thermoelectric Power Generator Coupled with Phase Change Material

OpenAIRE

Lim Chong C.; Al-Kayiem Hussain H.; Sing Chin Y.

2014-01-01

Solar is the intermittent source of renewable energy and all thermal solar systems having a setback on non-functioning during the night and cloudy environment. This paper presents alternative solution for power generation using thermoelectric which is the direct conversion of temperature gradient of hot side and cold side of thermoelectric material to electric voltage. Phase change material with latent heat effect would help to prolong the temperature gradient across thermoelectric material f...

Intermittent control: a computational theory of human control.

Science.gov (United States)

Gawthrop, Peter; Loram, Ian; Lakie, Martin; Gollee, Henrik

2011-02-01

The paradigm of continuous control using internal models has advanced understanding of human motor control. However, this paradigm ignores some aspects of human control, including intermittent feedback, serial ballistic control, triggered responses and refractory periods. It is shown that event-driven intermittent control provides a framework to explain the behaviour of the human operator under a wider range of conditions than continuous control. Continuous control is included as a special case, but sampling, system matched hold, an intermittent predictor and an event trigger allow serial open-loop trajectories using intermittent feedback. The implementation here may be described as "continuous observation, intermittent action". Beyond explaining unimodal regulation distributions in common with continuous control, these features naturally explain refractoriness and bimodal stabilisation distributions observed in double stimulus tracking experiments and quiet standing, respectively. Moreover, given that human control systems contain significant time delays, a biological-cybernetic rationale favours intermittent over continuous control: intermittent predictive control is computationally less demanding than continuous predictive control. A standard continuous-time predictive control model of the human operator is used as the underlying design method for an event-driven intermittent controller. It is shown that when event thresholds are small and sampling is regular, the intermittent controller can masquerade as the underlying continuous-time controller and thus, under these conditions, the continuous-time and intermittent controller cannot be distinguished. This explains why the intermittent control hypothesis is consistent with the continuous control hypothesis for certain experimental conditions.

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.

Limitation of fusion power plant installation on future power grids under the effect of renewable and nuclear power sources

Energy Technology Data Exchange (ETDEWEB)

Takeda, Shutaro, E-mail: takeda.shutarou.55r@st.kyoto-u.ac.jp [Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Kyoto (Japan); Sakurai, Shigeki [Graduate School of Advanced Integrated Studies in Human Survivability, Kyoto University, Kyoto, Kyoto (Japan); Yamamoto, Yasushi [Faculty of Engineering Science, Kansai University, Suita, Osaka (Japan); Kasada, Ryuta; Konishi, Satoshi [Institute of Advanced Energy, Kyoto University, Uji, Kyoto (Japan)

2016-11-01

Graphical abstract: - Highlights: • Future power grids would be unstable due to renewable and nuclear power sources. • Output interruptions of fusion plant would cause disturbances to future grids. • Simulation results suggested they would create limitations in fusion installation. • A novel diagram was presented to illustrate this suggested limitation. - Abstract: Future power grids would be unstable because of the larger share of renewable and nuclear power sources. This instability might bring some additional difficulties to fusion plant installation. Therefore, the authors carried out a quantitative feasibility study from the aspect of grid stability through simulation. Results showed that the more renewable and nuclear sources are linked to a grid, the greater disturbance the grid experiences upon a sudden output interruption of a fusion power plant, e.g. plasma disruption. The frequency deviations surpassed 0.2 Hz on some grids, suggesting potential limitations of fusion plant installation on future grids. To clearly show the suggested limitations of fusion plant installations, a novel diagram was presented.

Quasi-One-Dimensional Intermittent Flux Behavior in Superconducting Films

Directory of Open Access Journals (Sweden)

A. J. Qviller

2012-01-01

Full Text Available Intermittent filamentary dynamics of the vortex matter in superconductors is found in films of YBa_{2}Cu_{3}O_{7-δ} deposited on tilted substrates. Deposition of this material on such substrates creates parallel channels of easy flux penetration when a magnetic field is applied perpendicular to the film. As the applied field is gradually increased, magneto-optical imaging reveals that flux penetrates via numerous quasi-one-dimensional jumps. The distribution of flux avalanche sizes follows a power law, and data collapse is obtained by finite-size scaling, with the depth of the flux front used as crossover length. The intermittent behavior shows no threshold value in the applied field, in contrast to conventional flux jumping. The results strongly suggest that the quasi-one-dimensional flux jumps are of a different nature than the thermomagnetic dendritic (branching avalanches that are commonly found in superconducting films.

Kullback-Leibler divergence measure of intermittency: Application to turbulence

Science.gov (United States)

Granero-Belinchón, Carlos; Roux, Stéphane G.; Garnier, Nicolas B.

2018-01-01

For generic systems exhibiting power law behaviors, and hence multiscale dependencies, we propose a simple tool to analyze multifractality and intermittency, after noticing that these concepts are directly related to the deformation of a probability density function from Gaussian at large scales to non-Gaussian at smaller scales. Our framework is based on information theory and uses Shannon entropy and Kullback-Leibler divergence. We provide an extensive application to three-dimensional fully developed turbulence, seen here as a paradigmatic complex system where intermittency was historically defined and the concepts of scale invariance and multifractality were extensively studied and benchmarked. We compute our quantity on experimental Eulerian velocity measurements, as well as on synthetic processes and phenomenological models of fluid turbulence. Our approach is very general and does not require any underlying model of the system, although it can probe the relevance of such a model.

Lagrangian Statistics and Intermittency in Gulf of Mexico.

Science.gov (United States)

Lin, Liru; Zhuang, Wei; Huang, Yongxiang

2017-12-12

Due to the nonlinear interaction between different flow patterns, for instance, ocean current, meso-scale eddies, waves, etc, the movement of ocean is extremely complex, where a multiscale statistics is then relevant. In this work, a high time-resolution velocity with a time step 15 minutes obtained by the Lagrangian drifter deployed in the Gulf of Mexico (GoM) from July 2012 to October 2012 is considered. The measured Lagrangian velocity correlation function shows a strong daily cycle due to the diurnal tidal cycle. The estimated Fourier power spectrum E(f) implies a dual-power-law behavior which is separated by the daily cycle. The corresponding scaling exponents are close to -1.75 and -2.75 respectively for the time scale larger (resp. 0.1 ≤ f ≤ 0.4 day -1 ) and smaller (resp. 2 ≤ f ≤ 8 day -1 ) than 1 day. A Hilbert-based approach is then applied to this data set to identify the possible multifractal property of the cascade process. The results show an intermittent dynamics for the time scale larger than 1 day, while a less intermittent dynamics for the time scale smaller than 1 day. It is speculated that the energy is partially injected via the diurnal tidal movement and then transferred to larger and small scales through a complex cascade process, which needs more studies in the near future.

The impact of intermittent sources of energy on the market price of electricity

International Nuclear Information System (INIS)

Adigbli, Patrick; Mahuet, Audrey

2013-01-01

Parallel to liberalization of the electricity market, these past twenty years have been marked by a strong expansion of renewable energy in Europe. The increasing share of renewables in the energy mix - with a goal set by the European Commission at 20% by 2020 - has an impact on market prices. In the short run, subsidized intermittent energy may lead to lower prices or even to negative prices during certain periods of the year

Local load management system and intermittent power on the grid

Energy Technology Data Exchange (ETDEWEB)

NONE

2005-07-01

The project relates to the UK's obligations on renewable energy sources. The objectives were (i) to identify contractual requirements and commercial benefits of load management under the UK's Renewable Obligation and electric power trading arrangements (ii) through modelling, demonstrate the benefits of load management to major customers operating on-site wind generators; (iii) to develop a low-cost load management system incorporating communication technologies and switching devices and (iv) to identify the social and psychological aspects of load management. The demonstration of the load management system was conducted on the Findhorn Foundation's low voltage electric power distribution network and a 75kw wind turbine. The project demonstrated suitable technology for distributed load management on a grid-connected system in order to optimize the renewable energy generated on site, and the analyses identified several areas where grid-connected management can provide financial benefits. There is much scope for exploitation of commercial opportunities. The work was conducted by Econnect Ltd under contract to the DTI.

Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

Science.gov (United States)

Rodríguez-Lozano, Pablo; Verkaik, Iraima; Rieradevall, Maria; Prat, Narcís

2015-01-01

Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1) leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2) triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel), conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been extirpated, to restore

Small but powerful: top predator local extinction affects ecosystem structure and function in an intermittent stream.

Directory of Open Access Journals (Sweden)

Pablo Rodríguez-Lozano

Full Text Available Top predator loss is a major global problem, with a current trend in biodiversity loss towards high trophic levels that modifies most ecosystems worldwide. Most research in this area is focused on large-bodied predators, despite the high extinction risk of small-bodied freshwater fish that often act as apex consumers. Consequently, it remains unknown if intermittent streams are affected by the consequences of top-predators' extirpations. The aim of our research was to determine how this global problem affects intermittent streams and, in particular, if the loss of a small-bodied top predator (1 leads to a 'mesopredator release', affects primary consumers and changes whole community structures, and (2 triggers a cascade effect modifying the ecosystem function. To address these questions, we studied the top-down effects of a small endangered fish species, Barbus meridionalis (the Mediterranean barbel, conducting an enclosure/exclosure mesocosm experiment in an intermittent stream where B. meridionalis became locally extinct following a wildfire. We found that top predator absence led to 'mesopredator release', and also to 'prey release' despite intraguild predation, which contrasts with traditional food web theory. In addition, B. meridionalis extirpation changed whole macroinvertebrate community composition and increased total macroinvertebrate density. Regarding ecosystem function, periphyton primary production decreased in apex consumer absence. In this study, the apex consumer was functionally irreplaceable; its local extinction led to the loss of an important functional role that resulted in major changes to the ecosystem's structure and function. This study evidences that intermittent streams can be affected by the consequences of apex consumers' extinctions, and that the loss of small-bodied top predators can lead to large ecosystem changes. We recommend the reintroduction of small-bodied apex consumers to systems where they have been

CONDITIONED ANALYSIS OF HIGH-LATITUDE SOLAR WIND INTERMITTENCY

International Nuclear Information System (INIS)

D'Amicis, R.; Consolini, G.; Bavassano, B.; Bruno, R.

2012-01-01

The solar wind is a turbulent medium displaying intermittency. Its intermittent features have been widely documented and studied, showing how the intermittent character is different in fast and slow wind. In this paper, a statistical conditioned analysis of the solar wind intermittency for a period of high-latitude fast solar wind is presented. In particular, the intermittent features are investigated as a function of the Alfvénic degree of fluctuations at a given scale. The results show that the main contribution to solar wind intermittency is due to non-Alfvénic structures, while Alfvénic increments are found to be characterized by a smaller level of intermittency than the previous ones. Furthermore, the lifetime statistics of Alfvénic periods are discussed in terms of a multiscale texture of randomly oriented flux tubes.

Development of the power supplies of the prototype ion source for the EAST

International Nuclear Information System (INIS)

Liu Zhimin; Hu Chundong; Liu Sheng; Jiang Caichao; Song Shihua; Xie Yahong; Sheng Peng

2011-01-01

For the neutral beam injector (NBI) of the Experimental Advanced Superconducting Tokamak (EAST), a test stand of a high-current ion source has been in construction. The NBI power supply system includes the plasma generator power supply, plasma electrode power supply, high voltage power divider, negative high voltage power supply, and the transmission lines and the snubber. A multi-megawatt prototype ion source was developed. The arc discharge of the prototype ion source was obtained in the test. The test results for the ion source power supplies and the arc discharge of the ion source are presented. (authors)

High-power microwave generation from a frequency-stabilized virtual cathode source

International Nuclear Information System (INIS)

Fazio, M.V.; Hoeberling, R.F.; Kinross-Wright, J.

1988-01-01

The evolution of virtual cathode based high-power microwave-source technology has been directed primarily toward achieving higher peak-power levels. As peak powers in excess of 10 GW have been reported, attention has begun to focus on techniques for producing a more frequency- and phase-stable virtual cathode source. Free-running virtual cathode microwave sources characteristically exhibit bandwidths in a single pulse of tens of percent, which makes them unsuitable for many applications such as power sources for phased array antennas and microwave linear accelerators. Presented here are results of an experimental approach utilizing a high-Q, resonant cavity surrounding the oscillating virtual cathode to achieve frequency stabilization and repeatable narrow-band operation. A cylindrical cavity resonator is used with the microwave power being extracted radially through circumferential slot apertures into L-band waveguide

The JLab high power ERL light source

International Nuclear Information System (INIS)

Neil, G.R.; Behre, C.; Benson, S.V.

2006-01-01

A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered (superconducting) Linac (ERL). The machine has a 160MeV electron beam and an average current of 10mA in 75MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz ∼ half cycle pulse whose average brightness is >5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20W of average power extracted [Carr, et al., Nature 420 (2002) 153]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100fs pulses with >200W of average power. The FELs also provide record-breaking laser power [Neil, et al., Phys. Rev. Lett. 84 (2000) 662]: up to 10kW of average power in the IR from 1 to 14μm in 400fs pulses at up to 74.85MHz repetition rates and soon will produce similar pulses of 300-1000nm light at up to 3kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10ms long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and

The JLab high power ERL light source

Energy Technology Data Exchange (ETDEWEB)

G.R. Neil; C. Behre; S.V. Benson; M. Bevins; G. Biallas; J. Boyce; J. Coleman; L.A. Dillon-Townes; D. Douglas; H.F. Dylla; R. Evans; A. Grippo; D. Gruber; J. Gubeli; D. Hardy; C. Hernandez-Garcia; K. Jordan; M.J. Kelley; L. Merminga; J. Mammosser; W. Moore; N. Nishimori; E. Pozdeyev; J. Preble; R. Rimmer; Michelle D. Shinn; T. Siggins; C. Tennant; R. Walker; G.P. Williams and S. Zhang

2005-03-19

A new THz/IR/UV photon source at Jefferson Lab is the first of a new generation of light sources based on an Energy-Recovered, (superconducting) Linac (ERL). The machine has a 160 MeV electron beam and an average current of 10 mA in 75 MHz repetition rate hundred femtosecond bunches. These electron bunches pass through a magnetic chicane and therefore emit synchrotron radiation. For wavelengths longer than the electron bunch the electrons radiate coherently a broadband THz {approx} half cycle pulse whose average brightness is > 5 orders of magnitude higher than synchrotron IR sources. Previous measurements showed 20 W of average power extracted[1]. The new facility offers simultaneous synchrotron light from the visible through the FIR along with broadband THz production of 100 fs pulses with >200 W of average power. The FELs also provide record-breaking laser power [2]: up to 10 kW of average power in the IR from 1 to 14 microns in 400 fs pulses at up to 74.85 MHz repetition rates and soon will produce similar pulses of 300-1000 nm light at up to 3 kW of average power from the UV FEL. These ultrashort pulses are ideal for maximizing the interaction with material surfaces. The optical beams are Gaussian with nearly perfect beam quality. See www.jlab.org/FEL for details of the operating characteristics; a wide variety of pulse train configurations are feasible from 10 microseconds long at high repetition rates to continuous operation. The THz and IR system has been commissioned. The UV system is to follow in 2005. The light is transported to user laboratories for basic and applied research. Additional lasers synchronized to the FEL are also available. Past activities have included production of carbon nanotubes, studies of vibrational relaxation of interstitial hydrogen in silicon, pulsed laser deposition and ablation, nitriding of metals, and energy flow in proteins. This paper will present the status of the system and discuss some of the discoveries we have made

Source driven breeding thermal power reactors

International Nuclear Information System (INIS)

Greenspan, E.; Schneider, A.; Misulovin, A.; Gilai, D.; Levin, P.; Ben-Gurion Univ. of the Negev, Beersheba

1978-03-01

Improvements in the performance of fission power reactors made possible by designing them subcritical driven by D-T neutron sources are investigated. Light-water thermal systems are found to be most promising, neutronically and energetically, for the source driven mode of operation. The range of performance characteristics expected from breeding Light Water Hybrid Reactors (LWHR) is defined. Several promising types of LWHR blankets are identified. Options opened for the nuclear energy strategy by four types of the LWHRs are examined, and the potential contribution of these LWHRs to the nuclear energy economy are discussed. The power systems based on these LWHRs are found to enable a high utilization of the energy content of the uranium resources in all forms available - including depleted uranium and spent fuel from LWRs, while being free from the need for uranium enrichment and plutonium separation capabilities. (author)

An Enhanced Dual Droop Control Scheme for Resilient Active Power Sharing among Paralleled Two-Stage Converters

DEFF Research Database (Denmark)

Liu, Hongpeng; Yang, Yongheng; Wang, Xiongfei

2017-01-01

Traditional droop-controlled system has assumed that generators can always generate the powers demanded from them. This is true with conventional sources, where fuel supplies are usually planned in advance. For renewable sources, it may also be possible if energy storage is available. Energy...... storage, usually as batteries, may however be expensive, depending on its planned capacity. Renewable sources are therefore sometimes installed as non-dispatch-able sources without storage. This may not be viable for remote grids, where renewable sources may be the only or major type of sources. In those...... cases, traditional droop scheme may not work well when its demanded power cannot be met by some renewable sources due to intermittency. When that happens, the system may become unstable with some sources progressively brought out of generation. To avoid such occurrence, an enhanced dual droop scheme...

The Environment Friendly Power Source for Power Supply of Mobile Communication Base Stations

Science.gov (United States)

Rudenko, N. V.; Ershov, V. V.; Evstafiev, V. V.

2017-05-01

The article describes the technical proposals to improve environmental and resource characteristics of the autonomous power supply systems of mobile communication base stations based on renewable energy sources, while ensuring the required reliability and security of power supply. These include: the replacement of diesel-generator with clean energy source - an electrochemical generator based on hydrogen fuel cells; the use of wind turbines with a vertical axis; use of specialized batteries. Based on the analysis of the know technical solutions, the structural circuit diagram of the hybrid solar-wind-hydrogen power plant and the basic principles of the algorithm of its work were proposed. The implementation of these proposals will improve the environmental and resource characteristics.

Control for nuclear thermionic power source

International Nuclear Information System (INIS)

Fletcher, J.C.; Sawyer, C.D.

1978-01-01

A control for a power source is described which includes nuclear fuel interspersed with thermionic converters, including a power regulator that maintains a substantially constant output voltage to a variable load, and a control circuit that drives a neutron flux regulator in accordance with the current supplied to the power regulator and the neutron flux density in the region of the converters. The control circuit generates a control signal which is the difference between the neutron flux density and a linear fucntion of the current, and which drives the neutron regulator in a direction to decrease or increase the neutron flux according to the polarity of the control signal

Virtual power plant mid-term dispatch optimization

International Nuclear Information System (INIS)

Pandžić, Hrvoje; Kuzle, Igor; Capuder, Tomislav

2013-01-01

Highlights: ► Mid-term virtual power plant dispatching. ► Linear modeling. ► Mixed-integer linear programming applied to mid-term dispatch scheduling. ► Operation profit maximization combining bilateral contracts and the day-ahead market. -- Abstract: Wind power plants incur practically zero marginal costs during their operation. However, variable and uncertain nature of wind results in significant problems when trying to satisfy the contracted quantities of delivered electricity. For this reason, wind power plants and other non-dispatchable power sources are combined with dispatchable power sources forming a virtual power plant. This paper considers a weekly self-scheduling of a virtual power plant composed of intermittent renewable sources, storage system and a conventional power plant. On the one hand, the virtual power plant needs to fulfill its long-term bilateral contracts, while, on the other hand, it acts in the market trying to maximize its overall profit. The optimal dispatch problem is formulated as a mixed-integer linear programming model which maximizes the weekly virtual power plant profit subject to the long-term bilateral contracts and technical constraints. The self-scheduling procedure is based on stochastic programming. The uncertainty of the wind power and solar power generation is settled by using pumped hydro storage in order to provide flexible operation, as well as by having a conventional power plant as a backup. The efficiency of the proposed model is rendered through a realistic case study and analysis of the results is provided. Additionally, the impact of different storage capacities and turbine/pump capacities of pumped storage are analyzed.

Turbulence and intermittent transport at the boundary of magnetized plasmas

DEFF Research Database (Denmark)

Garcia, O.E.; Naulin, V.; Nielsen, A.H.

2005-01-01

Numerical fluid simulations of interchange turbulence for geometry and parameters relevant to the boundary region of magnetically confined plasmas are shown to result in intermittent transport qualitatively similar to recent experimental measurements. The two-dimensional simulation domain features...... a forcing region with spatially localized sources of particles and heat outside which losses due to the motion along open magnetic-field lines dominate, corresponding to the edge region and the scrape-off layer, respectively. Turbulent states reveal intermittent eruptions of hot plasma from the edge region...... fluctuation wave forms and transport statistics are also in a good agreement with those derived from the experiments. Associated with the turbulence bursts are relaxation oscillations in the particle and heat confinements as well as in the kinetic energy of the sheared poloidal flows. The formation of blob...

Batteryless, wireless sensor powered by a sediment microbial fuel cell.

Science.gov (United States)

Donovan, Conrad; Dewan, Alim; Heo, Deukhyoun; Beyenal, Haluk

2008-11-15

Sediment microbial fuel cells (SMFCs) are considered to be an alternative renewable power source for remote monitoring. There are two main challenges to using SMFCs as power sources: 1) a SMFC produces a low potential at which most sensor electronics do not operate, and 2) a SMFC cannot provide continuous power, so energy from the SMFC must be stored and then used to repower sensor electronics intermittently. In this study, we developed a SMFC and a power management system (PMS) to power a batteryless, wireless sensor. A SMFC operating with a microbial anode and cathode, located in the Palouse River, Pullman, Washington, U.S.A., was used to demonstrate the utility of the developed system. The designed PMS stored microbial energy and then started powering the wireless sensor when the SMFC potential reached 320 mV. It continued powering until the SMFC potential dropped below 52 mV. The system was repowered when the SMFC potential increased to 320 mV, and this repowering continued as long as microbial reactions continued. We demonstrated that a microbial fuel cell with a microbial anode and cathode can be used as an effective renewable power source for remote monitoring using custom-designed electronics.

Future wind power forecast errors, need for regulating power, and costs in the Swedish system

Energy Technology Data Exchange (ETDEWEB)

Carlsson, Fredrik [Vattenfall Research and Development AB, Stockholm (Sweden). Power Technology

2011-07-01

Wind power is one of the renewable energy sources in the electricity system that grows most rapid in Sweden. There are however two market challenges that need to be addressed with a higher proportion of wind power - that is variability and predictability. Predictability is important since the spot market Nord Pool Spot requires forecasts of production 12 - 36 hours ahead. The forecast errors must be regulated with regulating power, which is expensive for the actors causing the forecast errors. This paper has investigated a number of scenarios with 10 - 55 TWh of wind power installed in the Swedish system. The focus has been on a base scenario with 10 TWh new wind power consisting of 3,5 GW new wind power and 1,5 GW already installed power, which gives 5 GW. The results show that the costs for the forecast errors will increase as more intermittent production is installed. However, the increase can be limited by for instance trading on intraday market or increase quality of forecasts. (orig.)

Enhanced sources of acoustic power surrounding AR 11429

International Nuclear Information System (INIS)

Donea, Alina; Hanson, Christopher

2013-01-01

Multi-frequency power maps of the local acoustic oscillations show acoustic enhancements (''acoustic-power halos'') at high frequencies surrounding large active region. Computational seismic holography reveals a high-frequency ''acoustic-emission halo'', or ''seismic glory'' surrounding large active regions. In this study, we have applied computational seismic holography to map the seismic seismic source density surrounding AR 11429. Studies of HMI/SDO Doppler data, shows that the ''acoustic halos'' and the ''seismic glories'' are prominent at high frequencies 5–8 mHz. We investigate morphological properties of acoustic-power and acoustic emission halos around an active region to see if they are spatially correlated. Details about the local magnetic field from vectormagnetograms of AR 11429 are included. We identify a 15'' region of seismic deficit power (dark moat) shielding the white-light boundary of the active region. The size of the seismic moat is related to region of intermediate magnetic field strength. The acoustic moat is circled by the halo of enhanced seismic amplitude as well as enhanced seismic emission. Overall, the results suggest that features are related. However, if we narrow the frequency band to 5.5 – 6.5 mHz, we find that the seismic source density dominates over the local acoustic power, suggesting the existence of sources that emit more energy downward into the solar interior than upward toward the solar surface.

Design and simulation of front end power converter for a microgrid with fuel cells and solar power sources

Science.gov (United States)

Jeevargi, Chetankumar; Lodhi, Anuj; Sateeshkumar, Allu; Elangovan, D.; Arunkumar, G.

2017-11-01

The need for Renewable Energy Sources (RES) is increasing due to increased demand for the supply of power and it is also environment friendly.In the recent few years, the cost of generation of the power from the RES has been decreased. This paper aims to design the front end power converter which is required for integrating the fuel cells and solar power sources to the micro grid. The simulation of the designed front end converter is carried out in the PSIM 9.1.1 software. The results show that the designed front end power converter is sufficient for integrating the micro grid with fuel cells and solar power sources.

Nuclear power: an eco friendly energy source for sustainable development

International Nuclear Information System (INIS)

Obaidurrahman, K.; Singh, Om Pal

2009-01-01

When viewed from a large set of criteria such as abundance of energy resources, environmental impacts, low fuel inventory, quantum of waste generated and green house gas emissions, nuclear power can be considered as a large scale sustainable energy source. Among all energy sources, nuclear energy has perhaps the lowest impact on the environment, especially in relation to kilowatt-hr produced, because nuclear plants do not emit harmful gases and produce small quantity of waste. In other words, nuclear energy is the most environmental friendly electricity source. There are no significant adverse effects to water, land, habitat, species and air resources. The present paper discusses the sustainability and feasibility of nuclear power as an eco friendly energy source in the changing and challenging competitive power market. (author)

An improved electron impact ion source power supply

International Nuclear Information System (INIS)

Beaver, E.M.

1974-01-01

An electron impact ion source power supply has been developed that offers improved ion beam stability. The electrical adjustments of ion source parameters are more flexible, and safety features are incorporated to protect the electron emitting filament from accidental destruction. (author)

Intense neutron source: high-voltage power supply specifications

International Nuclear Information System (INIS)

Riedel, A.A.

1980-08-01

This report explains the need for and sets forth the electrical, mechanical and safety specifications for a high-voltage power supply to be used with the intense neutron source. It contains sufficient information for a supplier to bid on such a power supply

Power Electronics as Efficient Interface of Renewable Energy Sources

DEFF Research Database (Denmark)

Blaabjerg, Frede; Chen, Zhe; Kjær, Søren Bækhøj

2004-01-01

The global electrical energy consumption is steadily rising and consequently there is a demand to increase the power generation capacity. A significant percentage of the required capacity increase can be based on renewable energy sources. Wind turbine technology, as the most cost effective...... renewable energy conversion system, will play an important part in our future energy supply. But other sources like microturbines, photovoltaics and fuel cell systems may also be serious contributor to the power supply. Characteristically, power electronics will be an efficient and important interface...... to the grid and this paper will first briefly discuss three different alternative/ renewable energy sources. Next, various configurations of the wind turbine technology are presented, as this technology seems to be most developed and cost-effective. Finally, the developments and requirements from the grid...

Possible power source found for fiber optic lasers

International Nuclear Information System (INIS)

Krupa, Tyler J.

2000-01-01

Scientists at the US Department of Energy's Sandia National Laboratory are researching ways to use a new semiconductor alloy, indium gallium arsenide nitride (InGaAsN), as as photovoltaic power source for lasers in fiber optics and space communication satellites. The efficiency of electricity-generating solar cells utilizing InGaAsN is predicted to be 40%-nearly twice the efficiency rate of a standard silicon solar cell. The use of InGaAsN in solar cells is a potential power source for satellites and other space systems. (AIP) (c)

The Concept of Autonomous Power Supply System Fed with Renewable Energy Sources

Directory of Open Access Journals (Sweden)

Waldemar Fedak

2017-12-01

Full Text Available Sustainable economic development requires the use of renewable energy sources in a rational and thoughtful way. In Polish conditions the use of several types of renewable energy sources on a single setup is a new issue. In particular, hybrid devices in conjunction with intelligent energy systems, such as lighting systems are generally not used. Therefore, the Polish energy production still relies on the burning of coal. Despite their advantages, renewable energy sources are characterized by seasonality and considerable instability. Access to renewable energy varies daily and seasonally, hence activities promoting the use of autonomous, hybrid power systems must be intensified. The presented research aims at the development of the Autonomous Power Supply (APS system based on the so-called energy mix. Such a system works in an isolated arrangement and serves to reliably supply electricity from renewable sources for small residential or public utility devices in an urban area. Systems with up to 3 kW power consist of modules, whose modular design allows the combination of various power configurations and types of renewable energy used. The basic system consists of a primary power source, additional power source, emergency power source, energy storage device, weather station and controller. The energy mix depends on the geographical location of the system. The emergency source can be implemented as an on-grid connector or fuel power generator with the participation of 100% until the primary or accessory power source failure is removed. The energy storage system consists of batteries or supercapacitors. The proposed system can be combined to create a local network that automatically responds to energy shortages in various network nodes by adjusting the supply of electricity within the network depending on its needs. For Poland realistic solutions in this article are the new and modern answer to these requirements.

Switch: a planning tool for power systems with large shares of intermittent renewable energy.

Science.gov (United States)

Fripp, Matthias

2012-06-05

Wind and solar power are highly variable, so it is it unclear how large a role they can play in future power systems. This work introduces a new open-source electricity planning model--Switch--that identifies the least-cost strategy for using renewable and conventional generators and transmission in a large power system over a multidecade period. Switch includes an unprecedented amount of spatial and temporal detail, making it possible to address a new type of question about the optimal design and operation of power systems with large amounts of renewable power. A case study of California for 2012-2027 finds that there is no maximum possible penetration of wind and solar power--these resources could potentially be used to reduce emissions 90% or more below 1990 levels without reducing reliability or severely raising the cost of electricity. This work also finds that policies that encourage customers to shift electricity demand to times when renewable power is most abundant (e.g., well-timed charging of electric vehicles) could make it possible to achieve radical emission reductions at moderate costs.

Power supply system for negative ion source at IPR

Science.gov (United States)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K. G.; Soni, Jignesh; Bandyopadhyay, M.; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-02-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ~5 × 1012 cm-3, from which ~ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (~15 to 35kV), and high current (~ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (~50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (~ 50kV) isolated from the system. The paper shall present the

Power supply system for negative ion source at IPR

International Nuclear Information System (INIS)

Gahlaut, Agrajit; Sonara, Jashwant; Parmar, K G; Soni, Jignesh; Bandyopadhyay, M; Singh, Mahendrajit; Bansal, Gourab; Pandya, Kaushal; Chakraborty, Arun

2010-01-01

The first step in the Indian program on negative ion beams is the setting up of Negative ion Experimental Assembly - RF based, where 100 kW of RF power shall be coupled to a plasma source producing plasma of density ∼5 x 10 12 cm -3 , from which ∼ 10 A of negative ion beam shall be produced and accelerated to 35 kV, through an electrostatic ion accelerator. The experimental system is modelled similar to the RF based negative ion source, BATMAN presently operating at IPP, Garching, Germany. The mechanical system for Negative Ion Source Assembly is close to the IPP source, remaining systems are designed and procured principally from indigenous sources, keeping the IPP configuration as a base line. High voltage (HV) and low voltage (LV) power supplies are two key constituents of the experimental setup. The HV power supplies for extraction and acceleration are rated for high voltage (∼15 to 35kV), and high current (∼ 15 to 35A). Other attributes are, fast rate of voltage rise (< 5ms), good regulation (< ±1%), low ripple (< ±2%), isolation (∼50kV), low energy content (< 10J) and fast cut-off (< 100μs). The low voltage (LV) supplies required for biasing and providing heating power to the Cesium oven and the plasma grids; have attributes of low ripple, high stability, fast and precise regulation, programmability and remote operation. These power supplies are also equipped with over-voltage, over-current and current limit (CC Mode) protections. Fault diagnostics, to distinguish abnormal rise in currents (breakdown faults) with over-currents is enabled using fast response breakdown and over-current protection scheme. To restrict the fault energy deposited on the ion source, specially designed snubbers are implemented in each (extraction and acceleration) high voltage path to swap the surge energy. Moreover, the monitoring status and control signals from these power supplies are required to be electrically (∼ 50kV) isolated from the system. The paper shall

Development of a method to evaluate shared alternate AC power source effects in multi-unit nuclear power plants

International Nuclear Information System (INIS)

Jung, Woo Sik; Yang, Joon Eun

2003-07-01

In order to evaluate accurately a Station BlackOut (SBO) event frequency of a multi-unit nuclear power plant that has a shared Alternate AC (AAC) power source, an approach has been developed which accommodates the complex inter-unit behavior of the shared AAC power source under multi-unit Loss Of Offsite Power (LOOP) conditions. The approach is illustrated for two cases, 2 units and 4 units at a single site, and generalized for a multi-unit site. Furthermore, the SBO frequency of the first unit of the 2-unit site is quantified. The SBO frequency at a target unit of Probabilistic Safety Assessment (PSA) could be underestimated if the inter-unit dependency of the shared AAC power source is not properly modeled. The effect of the inter-unit behavior of the shared AAC power source on the SBO frequency is not negligible depending on the Common Cause Failure (CCF) characteristics among AC power sources. The methodology suggested in the present report is believed to be very useful in evaluating the SBO frequency and the core damage frequency resulting from the SBO event. This approach is also applicable to the probabilistic evaluation of the other shared systems in a multi-unit nuclear power plant

Pressure Autoregulation Measurement Techniques in Adult Traumatic Brain Injury, Part I: A Scoping Review of Intermittent/Semi-Intermittent Methods.

Science.gov (United States)

Zeiler, Frederick A; Donnelly, Joseph; Calviello, Leanne; Menon, David K; Smielewski, Peter; Czosnyka, Marek

2017-12-01

The purpose of this study was to perform a systematic, scoping review of commonly described intermittent/semi-intermittent autoregulation measurement techniques in adult traumatic brain injury (TBI). Nine separate systematic reviews were conducted for each intermittent technique: computed tomographic perfusion (CTP)/Xenon-CT (Xe-CT), positron emission tomography (PET), magnetic resonance imaging (MRI), arteriovenous difference in oxygen (AVDO 2 ) technique, thigh cuff deflation technique (TCDT), transient hyperemic response test (THRT), orthostatic hypotension test (OHT), mean flow index (Mx), and transfer function autoregulation index (TF-ARI). MEDLINE ® , BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library (inception to December 2016), and reference lists of relevant articles were searched. A two tier filter of references was conducted. The total number of articles utilizing each of the nine searched techniques for intermittent/semi-intermittent autoregulation techniques in adult TBI were: CTP/Xe-CT (10), PET (6), MRI (0), AVDO 2 (10), ARI-based TCDT (9), THRT (6), OHT (3), Mx (17), and TF-ARI (6). The premise behind all of the intermittent techniques is manipulation of systemic blood pressure/blood volume via either chemical (such as vasopressors) or mechanical (such as thigh cuffs or carotid compression) means. Exceptionally, Mx and TF-ARI are based on spontaneous fluctuations of cerebral perfusion pressure (CPP) or mean arterial pressure (MAP). The method for assessing the cerebral circulation during these manipulations varies, with both imaging-based techniques and TCD utilized. Despite the limited literature for intermittent/semi-intermittent techniques in adult TBI (minus Mx), it is important to acknowledge the availability of such tests. They have provided fundamental insight into human autoregulatory capacity, leading to the development of continuous and more commonly applied techniques in the intensive care unit (ICU). Numerous methods of

Water quality effects of intermittent water supply in Arraiján, Panama.

Science.gov (United States)

Erickson, John J; Smith, Charlotte D; Goodridge, Amador; Nelson, Kara L

2017-05-01

Intermittent drinking water supply is common in low- and middle-income countries throughout the world and can cause water quality to degrade in the distribution system. In this study, we characterized water quality in one study zone with continuous supply and three zones with intermittent supply in the drinking water distribution network in Arraiján, Panama. Low or zero pressures occurred in all zones, and negative pressures occurred in the continuous zone and two of the intermittent zones. Despite hydraulic conditions that created risks for backflow and contaminant intrusion, only four of 423 (0.9%) grab samples collected at random times were positive for total coliform bacteria and only one was positive for E. coli. Only nine of 496 (1.8%) samples had turbidity >1.0 NTU and all samples had ≥0.2 mg/L free chlorine residual. In contrast, water quality was often degraded during the first-flush period (when supply first returned after an outage). Still, routine and first-flush water quality under intermittent supply was much better in Arraiján than that reported in a previous study conducted in India. Better water quality in Arraiján could be due to better water quality leaving the treatment plant, shorter supply outages, higher supply pressures, a more consistent and higher chlorine residual, and fewer contaminant sources near pipes. The results illustrate that intermittent supply and its effects on water quality can vary greatly between and within distribution networks. The study also demonstrated that monitoring techniques designed specifically for intermittent supply, such as continuous pressure monitoring and sampling the first flush, can detect water quality threats and degradation that would not likely be detected with conventional monitoring. Copyright © 2017 Elsevier Ltd. All rights reserved.

Cost-minimized combinations of wind power, solar power and electrochemical storage, powering the grid up to 99.9% of the time

DEFF Research Database (Denmark)

Budischak, Cory; Sewell, DeAnna; Thomson, Heather

2013-01-01

intermittent power, we seek combinations of diverse renewables at diverse sites, with storage, that are not intermittent and satisfy need a given fraction of hours. And 2) we seek minimal cost, calculating true cost of electricity without subsidies and with inclusion of external costs. Our model evaluated over...... renewable generation and the excess capacity together meet electric load with less storage, lowering total system cost. At 2030 technology costs and with excess electricity displacing natural gas, we find that the electric system can be powered 90%–99.9% of hours entirely on renewable electricity, at costs...

Decentralized and Real-Time Power Dispatch Control for an Islanded Microgrid Supported by Distributed Power Sources

Directory of Open Access Journals (Sweden)

Changsun Ahn

2013-12-01

Full Text Available Microgrids can deploy traditional and/or renewable power sources to support remote sites. Utilizing renewable power sources requires more complicated control strategies to achieve acceptable power quality and maintain grid stability. In this research, we assume that the grid stability problem is already solved. As a next step, we focus on how the power can be dispatched from multiple power sources for improved grid efficiency. Isolated microgrids frequently require reconfigurations because of the grid expansion or component failures. Therefore, the control strategies ideally should be implemented in a plug-and-play fashion. Moreover, these strategies ideally require no pre-knowledge of the grid structure, and as little communication with neighboring power sources as possible. The control objective is to minimize a cost function that can be adjusted to reflect the desire to minimize energy cost and/or losses. An algorithm is designed to satisfy a derived necessary condition of function optimality. Such conditions are obtained by formulating Lagrange functions. An equivalent grid model approximates the grid structure which was later confirmed to represent the grid behavior adequately. For decentralized operations, we execute the distributed control sequentially using a simple token communication protocol. The performance of the combined system identification-Lagrange function minimization algorithm is demonstrated through simulations.

Power flow modelling in electric networks with renewable energy sources in large areas

International Nuclear Information System (INIS)

Buhawa, Z. M.; Dvorsky, E.

2012-01-01

In many worlds regions there is a great potential for utilizing home grid connected renewable power generating systems, with capacities of MW thousands. The optimal utilization of these sources is connected with power flow possibilities trough the power network in which they have to be connected. There is necessary to respect the long distances among the electric power sources with great outputs and power consumption and non even distribution of the power sources as well. The article gives the solution possibilities for Libya region under utilization of wind renewable sources in north in shore regions. (Authors)

On-line measurement of microwave power in ECR ion source

International Nuclear Information System (INIS)

Zhou Changgeng; Kang Wu; Hu Yonghong; Li Yan; Lou Benchao; Zu Xiulan; Xiong Riheng; Chen Junguang; Li Xiaoyun

2005-01-01

It is a new technology to apply an ECR ion source to the neutron generator. Because of the structure limitation, working state of the ECR ion source could not be judged by the color of gas discharging in discharge chamber. Therefore, it was hard to estimate if the ECR ion source was working properly in the neutron generator. The method to resolve the problem was described in this paper. The microwave power was measured on-line by a directional coupler and a small microwave power meter. The ion beam current could be educed from the measured incidence microwave power, and discharge state in discharge chamber could be determined. (authors)

A new coaxial high power microwave source based on dual beams

Energy Technology Data Exchange (ETDEWEB)

Li, Yangmei, E-mail: sunberry1211@hotmail.com; Zhang, Xiaoping; Qi, Zumin; Dang, Fangchao; Qian, Baoliang [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2014-05-15

We present a new coaxial high power microwave source based on dual beams, which combines a relativistic backward wave oscillator (RBWO) (noted as the inner sub-source below) and a coaxial transit-time oscillator (TTO) (noted as the outer sub-source). The cathode consists of an inner and an outer annular cathode, which provides the inner and the outer annular electron beam for the sub-sources, respectively. Particle-in-cell (PIC) simulation results demonstrate that power conversion efficiencies of the two sub-sources with an identical frequency of 9.74 GHz are 29% and 25%, respectively. It is furthermore found that phase locking between the inner and the outer sub-sources can be realized, which suggests a feasibility to obtain a higher power output if the two microwave signals are coherently combined.

A new coaxial high power microwave source based on dual beams

International Nuclear Information System (INIS)

Li, Yangmei; Zhang, Xiaoping; Qi, Zumin; Dang, Fangchao; Qian, Baoliang

2014-01-01

We present a new coaxial high power microwave source based on dual beams, which combines a relativistic backward wave oscillator (RBWO) (noted as the inner sub-source below) and a coaxial transit-time oscillator (TTO) (noted as the outer sub-source). The cathode consists of an inner and an outer annular cathode, which provides the inner and the outer annular electron beam for the sub-sources, respectively. Particle-in-cell (PIC) simulation results demonstrate that power conversion efficiencies of the two sub-sources with an identical frequency of 9.74 GHz are 29% and 25%, respectively. It is furthermore found that phase locking between the inner and the outer sub-sources can be realized, which suggests a feasibility to obtain a higher power output if the two microwave signals are coherently combined

Environmentally friendly power sources for aerospace applications

Science.gov (United States)

Lapeña-Rey, Nieves; Mosquera, Jonay; Bataller, Elena; Ortí, Fortunato; Dudfield, Christopher; Orsillo, Alessandro

One of the crucial challenges of the aviation industry in upcoming years is to reduce emissions not only in the vicinity of airfields but also in cruise. Amongst other transport methods, airplanes emissions count for 3% of the CO 2 emissions. Initiatives to reduce this include not only investing in more fuel-efficient aircrafts or adapting existing ones to make them more efficient (e.g. by fitting fuel-saving winglets), but also more actively researching novel propulsion systems that incorporate environmentally friendly technologies. The Boeing Company through its European subsidiary, Boeing Research and Technology Europe (BR&TE) in collaboration with industry partners throughout Europe is working towards this goal by studying the possible application of advanced batteries and fuel-cell systems in aeronautical applications. One example is the development of a small manned two-seater prototype airplane powered only by proton exchange membrane (PEM) fuel-cell stacks, which runs on compressed hydrogen gas as fuel and pressurized air as oxidant, and Li-ion batteries. The efficient all composite motorglider is an all electric prototype airplane which does not produce any of the noxious engine exhaust by-products, such as carbon dioxide, carbon monoxide or NO x, that can contribute to climate change and adversely affect local air quality. Water and heat are the only exhaust products. The main objective is to demonstrate for the first time in aviation history a straight level manned flight with fuel-cells as the only power source. For this purpose, the original engine of a super Dimona HK36TTC glider from Diamond Aircraft Industries (Austria) was replaced by a hybrid power system, which feeds a brushless dc electrical motor that rotates a variable pitch propeller. Amongst the many technical challenges encountered when developing this test platform are maintaining the weight and balance of the aircraft, designing the thermal management system and the power management

Environmentally friendly power sources for aerospace applications

Energy Technology Data Exchange (ETDEWEB)

Lapena-Rey, Nieves; Mosquera, Jonay; Bataller, Elena; Orti, Fortunato [Boeing Research and Technology Europe Ltd., Environmental Technologies, C/ Canada Real de las Merinas 1-3, Building 4, 4th floor, Madrid 28042 (Spain); Dudfield, Christopher; Orsillo, Alessandro [Intelligent Energy Ltd., The Innovation Centre, Epinal Way, Loughborough LE11 3EH (United Kingdom)

2008-07-01

One of the crucial challenges of the aviation industry in upcoming years is to reduce emissions not only in the vicinity of airfields but also in cruise. Amongst other transport methods, airplanes emissions count for 3% of the CO{sub 2} emissions. Initiatives to reduce this include not only investing in more fuel-efficient aircrafts or adapting existing ones to make them more efficient (e.g. by fitting fuel-saving winglets), but also more actively researching novel propulsion systems that incorporate environmentally friendly technologies. The Boeing Company through its European subsidiary, Boeing Research and Technology Europe (BR and TE) in collaboration with industry partners throughout Europe is working towards this goal by studying the possible application of advanced batteries and fuel-cell systems in aeronautical applications. One example is the development of a small manned two-seater prototype airplane powered only by proton exchange membrane (PEM) fuel-cell stacks, which runs on compressed hydrogen gas as fuel and pressurized air as oxidant, and Li-ion batteries. The efficient all composite motorglider is an all electric prototype airplane which does not produce any of the noxious engine exhaust by-products, such as carbon dioxide, carbon monoxide or NOx, that can contribute to climate change and adversely affect local air quality. Water and heat are the only exhaust products. The main objective is to demonstrate for the first time in aviation history a straight level manned flight with fuel-cells as the only power source. For this purpose, the original engine of a super Dimona HK36TTC glider from Diamond Aircraft Industries (Austria) was replaced by a hybrid power system, which feeds a brushless dc electrical motor that rotates a variable pitch propeller. Amongst the many technical challenges encountered when developing this test platform are maintaining the weight and balance of the aircraft, designing the thermal management system and the power

Optimal intermittent search strategies

International Nuclear Information System (INIS)

Rojo, F; Budde, C E; Wio, H S

2009-01-01

We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion

Compact high-power terahertz radiation source

Directory of Open Access Journals (Sweden)

G. A. Krafft

2004-06-01

Full Text Available In this paper a new type of THz radiation source, based on recirculating an electron beam through a high gradient superconducting radio frequency cavity, and using this beam to drive a standard electromagnetic undulator on the return leg, is discussed. Because the beam is recirculated and not stored, short bunches may be produced that radiate coherently in the undulator, yielding exceptionally high average THz power for relatively low average beam power. Deceleration from the coherent emission, and the detuning it causes, limits the charge-per-bunch possible in such a device.

Radiation Tolerant Low Power Precision Time Source, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The availability of small, low power atomic clocks is now a reality for ground-based and airborne navigation systems. Kernco's Low Power Precision Time Source...

Governance of Open Source Software Foundations: Who Holds the Power?

Directory of Open Access Journals (Sweden)

Ludovico Prattico

2012-12-01

Full Text Available The research reported in this article attempts to discover who holds the power in open source software foundations through the analysis of governance documents. Artificial neural network analysis is used to analyse the content of the bylaws of six open source foundations (Apache, Eclipse, GNOME, Plone, Python, and SPI for the purpose of identifying power structures. Results of the research suggest that: i the actions of an open source software foundation are centered around one of three groups: Members, Chairman/President/Executive Director, and Board of Directors; ii in only one of the six foundations is the Board of Directors responsible for both the community and the product; and iii artificial neural network analysis of the content of bylaws provides unbiased insights of the power structure of open source software foundations. These results may prove useful to those who contribute to open source foundations and use their products and services.

A New Configuration for Power Sharing of Two Z-Source Inverters

Directory of Open Access Journals (Sweden)

M. Ghani varzaneh

2017-09-01

Full Text Available This paper presents a new structure to provide the ability for power sharing of two Z-source inverters. According to the operation principles of Z-source inverters, only one input source supplies the circuit, which is a limitation particularly for the stand alone systems feeded by limited output power such as photovoltaics and feul cells. Furthermore; if one source fails to supply,  the load can't be supplied. This paper covers those via interconnection of impedance network of two Z-source inverters. The operating principles of the proposed topology for the stand-alone and power sharing conditions are described and the relations are derived. The topology is simulated, which the results verify the theoretical analysis and well performance of the system. 

46 CFR 112.01-20 - Final emergency power source.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Final emergency power source. 112.01-20 Section 112.01-20 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING EMERGENCY LIGHTING AND POWER SYSTEMS Definitions of Emergency Lighting and Power Systems § 112.01-20 Final emergency...

Operational flexibility and economics of power plants in future low-carbon power systems

NARCIS (Netherlands)

Brouwer, Anne Sjoerd; van den Broek, Machteld; Seebregts, Ad; Faaij, André

2015-01-01

Future power systems will require large shares of low-carbon generators such as renewables and power plants with Carbon Capture and Storage (CCS) to keep global warming below 2. °C. Intermittent renewables increase the system-wide demand for flexibility and affect the operation of thermal power

Intermittency in {sup 197}Au fragmentation

Energy Technology Data Exchange (ETDEWEB)

Dabrowska, A; Holynski, R; Olszewski, A; Szarska, M; Wilczynska, B; Wolter, W; Wosiek, B [Institute of Nuclear Physics, Cracow (Poland); Cherry, M L; Deines-Jones, P; Jones, W V; Sengupta, K; Wefel, B [Louisiana State Univ., Baton Rouge, LA (United States). Dept. of Physics and Astronomy; Waddington, C J [Minnesota Univ., Minneapolis, MN (United States). School of Physics and Astronomy; Pozharova, E A; Skorodko, T Yu [Inst. of Theoretical and Experimental Physics, Moscow (Russian Federation); KLMM Collaboration

1995-07-01

The concept of factorial moments was applied to an analysis of the dynamical fluctuations in the charge distributions of the fragments emitted from gold nuclei with energies 10.6 and < 1.0 GeV/n interacting with emulsion nuclei. Clear evidence for intermittent fluctuations has been found in an analysis using all the particles released from the gold projectile, with a stronger effect observed below 1 GeV/n than at 10.6 GeV/n. For the full data sets, however, the intermittency effect was found to be very sensitive to the singly charged particles, and neglecting these particles strongly reduces the intermittency signal. When the analysis is restricted to the multiply charged fragments, an intermittency effect is revealed only for multifragmentation events, although one that is enhanced as compared to the analysis of all, singly and multiply charged, particles. The properties of the anomalous fractal dimensions suggest a sequential decay mechanism, rather than the existence of possible critical behaviour in the process of nuclear fragmentation. The likely influence of the charge conservation effects and the finite size of decaying systems on the observed intermittency signals was pointed out. (author). 37 refs, 9 figs, 5 tabs.

Power Controllability of Three-phase Converter with Unbalanced AC Source

DEFF Research Database (Denmark)

Ma, Ke; Liserre, Marco; Blaabjerg, Frede

2013-01-01

Three-phase DC-AC power converters suffer from power oscillation and overcurrentt problems in case of unbalanced AC source voltage that can be caused by grid/generator faults. Existing solutions to handle these problems are properly selecting and controlling the positive and negative sequence...... currents. In this work a new series of control strategies which utilize the zero-sequence components are proposed to enhance the power control ability under this adverse conditions. It is concluded that by introducing proper zero sequence current controls and corresponding circuit configurations, the power...... converter can enable more flexible control targets, achieving better performances in the delivered power and load current when suffering from unbalanced AC sources....

Experiences with on-site power sources at KCB

Energy Technology Data Exchange (ETDEWEB)

Heijnen, B. M.A. [Borssele Nuclear Power Station, N.V. P.Z.E.M., Postbus 48, 4330 AA Middleburg (Netherlands)

1986-02-15

The design of the nuclear power station is of the late sixties. The experiences with the on-site power sources, signal processing and some of the resulting modifications of the design of the power plant are mentioned. In order to let the design satisfy as much as possible present ideas about safety, it was decided to realize a total new and Independent decay heat removal System. With this system a second independent on-site power System is at disposal in case of accident situations. (author)

Optimal intermittent search strategies

Energy Technology Data Exchange (ETDEWEB)

Rojo, F; Budde, C E [FaMAF, Universidad Nacional de Cordoba, Ciudad Universitaria, X5000HUA Cordoba (Argentina); Wio, H S [Instituto de Fisica de Cantabria, Universidad de Cantabria and CSIC E-39005 Santander (Spain)

2009-03-27

We study the search kinetics of a single fixed target by a set of searchers performing an intermittent random walk, jumping between different internal states. Exploiting concepts of multi-state and continuous-time random walks we have calculated the survival probability of a target up to time t, and have 'optimized' (minimized) it with regard to the transition probability among internal states. Our model shows that intermittent strategies always improve target detection, even for simple diffusion states of motion.

Evaluation of power transfer efficiency for a high power inductively coupled radio-frequency hydrogen ion source

Science.gov (United States)

Jain, P.; Recchia, M.; Cavenago, M.; Fantz, U.; Gaio, E.; Kraus, W.; Maistrello, A.; Veltri, P.

2018-04-01

Neutral beam injection (NBI) for plasma heating and current drive is necessary for International Thermonuclear Experimental reactor (ITER) tokamak. Due to its various advantages, a radio frequency (RF) driven plasma source type was selected as a reference ion source for the ITER heating NBI. The ITER relevant RF negative ion sources are inductively coupled (IC) devices whose operational working frequency has been chosen to be 1 MHz and are characterized by high RF power density (˜9.4 W cm-3) and low operational pressure (around 0.3 Pa). The RF field is produced by a coil in a cylindrical chamber leading to a plasma generation followed by its expansion inside the chamber. This paper recalls different concepts based on which a methodology is developed to evaluate the efficiency of the RF power transfer to hydrogen plasma. This efficiency is then analyzed as a function of the working frequency and in dependence of other operating source and plasma parameters. The study is applied to a high power IC RF hydrogen ion source which is similar to one simplified driver of the ELISE source (half the size of the ITER NBI source).

Conventional power sources for colliders

International Nuclear Information System (INIS)

Allen, M.A.

1987-07-01

At SLAC we are developing high peak-power klystrons to explore the limits of use of conventional power sources in future linear colliders. In an experimental tube we have achieved 150 MW at 1 μsec pulse width at 2856 MHz. In production tubes for SLAC Linear Collider (SLC) we routinely achieve 67 MW at 3.5 μsec pulse width and 180 pps. Over 200 of the klystrons are in routine operation in SLC. An experimental klystron at 8.568 GHz is presently under construction with a design objective of 30 MW at 1 μsec. A program is starting on the relativistic klystron whose performance will be analyzed in the exploration of the limits of klystrons at very short pulse widths

Feasibility study for the partial conversion of a hydropower plant into a pumped-storage power plant: a case study of hydroelectric power plant La Barca (Asturias, Spain

Directory of Open Access Journals (Sweden)

E. Antuña Yudego

2017-01-01

Full Text Available Renewable energy sources have reported an unprecedented increase of global installed renewable power capacity. Against the advantages provided by this renewable power generation technology it should be taken into account an important issue: these intermittent energy sources supply a fluctuating output which is difficult to manage. Pumped-storage hydro power plants reappear in these circumstances as an efficient form of energy storage which allows to use reserves when necessary, enabling power generation output to cover continuously this energy demand. The present paper shows a simplified feasibility study of the partial conversion of hydropower plant La Barca, in Asturias, into a reversible storage through the development of an algorithm to simulate its operation according to electricity market prices. For this purpose, the operation in the deviation management market is considered and the technical modifications required for the conversion are shown. The estimation of costs and incomes present a feasible scenario.

Application of RI power sources to cardiac pacemakers and aftercare in its implantation

International Nuclear Information System (INIS)

Hori, Motokazu

1974-01-01

RI power sources have long life when they are implanted into human bodies together with cardiac pacemakers, as compared with e.g. mercury batteries. Therefore, the frequency of their replacement can be by far less. However, there are the problems of radiation protection, high cost, availability, etc. The following matters are described: The cardiac pacemaker and its power supply, implantation into human body, problems with patients and conventional power sources; the current state of RI power sources for cardiac pacemakers, including plutonium-238 RTG and 147 Pm and 3 H batteries; and problems with the RI power sources. (Mori, K.)

A novel power source for high-precision, highly efficient micro w-EDM

International Nuclear Information System (INIS)

Chen, Shun-Tong; Chen, Chi-Hung

2015-01-01

The study presents the development of a novel power source for high-precision, highly efficient machining of micropart microstructures using micro wire electrical discharge machining (w-EDM). A novel power source based on a pluri resistance–capacitance (pRC) circuit that can generate a high-frequency, high-peak current with a short pulse train is proposed and designed to enhance the performance of micro w-EDM processes. Switching between transistors is precisely controlled in the designed power source to create a high-frequency short-pulse train current. Various microslot cutting tests in both aluminum and copper alloys are conducted. Experimental results demonstrate that the pRC power source creates instant spark erosion resulting in markedly less material for removal, diminishing discharge crater size, and consequently an improved surface finish. A new evaluation approach for spark erosion ability (SEA) to assess the merits of micro EDM power sources is also proposed. In addition to increasing the speed of micro w-EDM by increasing wire feed rates by 1.6 times the original feed rate, the power source is more appropriate for machining micropart microstructures since there is less thermal breaking. Satisfactory cutting of an elaborate miniature hook-shaped structure and a high-aspect ratio microstructure with a squared-pillar array also reveal that the developed pRC power source is effective, and should be very useful in the manufacture of intricate microparts. (paper)

Comparing costs of power and heat production by prospective and present sources

International Nuclear Information System (INIS)

Novak, S.

1979-01-01

Capital and running costs are compared of power and heat production from different sources. The lowest capital costs were found for coal-fired power plants followed by light water reactor power plants. The capital costs of other types of power plants, such as wind, geothermal, solar, thermonuclear power plants are significantly higher. The estimated specific cost for electric power production in 1985 for a nuclear power plant is lower than for a fossil-fuel power plant. It is estimated that in 1985 coal will be the cheapest heat source. (Ha)

Intermittency of gravity wave momentum flux in the mesopause region observed with an all-sky airglow imager

Science.gov (United States)

Cao, Bing; Liu, Alan Z.

2016-01-01

The intermittency of gravity wave momentum flux (MF) near the OH airglow layer (˜87 km) in the mesopause region is investigated for the first time using observation of all-sky airglow imager over Maui, Hawaii (20.7°N, 156.3°W), and Cerro Pachón, Chile (30.3°S, 70.7°W). At both sites, the probability density function (pdf) of gravity wave MF shows two distinct distributions depending on the magnitude of the MF. For MF smaller (larger) than ˜16 m2 s-2 (0.091 mPa), the pdf follows a lognormal (power law) distribution. The intermittency represented by the Bernoulli proxy and the percentile ratio shows that gravity waves have higher intermittency at Maui than at Cerro Pachón, suggesting more intermittent background variation above Maui. It is found that most of the MF is contributed by waves that occur very infrequently. But waves that individually contribute little MF are also important because of their higher occurrence frequencies. The peak contribution is from waves with MF around ˜2.2 m2 s-2 at Cerro Pachón and ˜5.5 m2 s-2 at Maui. Seasonal variations of the pdf and intermittency imply that the background atmosphere has larger influence on the observed intermittency in the mesopause region.

Energy Storage for Power Systems Applications: A Regional Assessment for the Northwest Power Pool (NWPP)

Energy Technology Data Exchange (ETDEWEB)

Kintner-Meyer, Michael CW; Balducci, Patrick J.; Jin, Chunlian; Nguyen, Tony B.; Elizondo, Marcelo A.; Viswanathan, Vilayanur V.; Guo, Xinxin; Tuffner, Francis K.

2010-04-01

Wind production, which has expanded rapidly in recent years, could be an important element in the future efficient management of the electric power system; however, wind energy generation is uncontrollable and intermittent in nature. Thus, while wind power represents a significant opportunity to the Bonneville Power Administration (BPA), integrating high levels of wind resources into the power system will bring great challenges to generation scheduling and in the provision of ancillary services. This report addresses several key questions in the broader discussion on the integration of renewable energy resources in the Pacific Northwest power grid. More specifically, it addresses the following questions: a) how much total reserve or balancing requirements are necessary to accommodate the simulated expansion of intermittent renewable energy resources during the 2019 time horizon, and b) what are the most cost effective technological solutions for meeting load balancing requirements in the Northwest Power Pool (NWPP).

Gun power source for electron gun of 3 MeV DC accelerator

International Nuclear Information System (INIS)

Dewangan, S.; Sharma, D.K.; Nanu, K.

2011-01-01

In DC electron beam accelerator electron gun is situated at high voltage terminal which requires constant power irrespective of beam energy. Floating power source is required for gun. This paper describes the scheme of static gun power source derived from parallel coupled voltage multiplier column. (author)

Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

Energy Technology Data Exchange (ETDEWEB)

Zhou, Gengji

2017-11-15

Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

Power scaling of ultrafast mid-IR source enabled by high-power fiber laser technology

International Nuclear Information System (INIS)

Zhou, Gengji

2017-11-01

Ultrafast laser sources with high repetition-rate (>10 MHz) and tunable in the mid-infrared (IR) wavelength range of 7-18 μm hold promise for many important spectroscopy applications. Currently, these ultrafast mid- to longwavelength-IR sources can most easily be achieved via difference-frequency generation (DFG) between a pump beam and a signal beam. However, current ultrafast mid- to longwavelength-IR sources feature a low average power, which limits their applications. In this thesis, we propose and demonstrate a novel approach to power scaling of DFG-based ultrafast mid-IR laser sources. The essence of this novel approach is the generation of a high-energy signal beam. Both the pump beam and the signal beam are derived from a home-built Yb-fiber laser system that emits 165-fs pulses centered at 1035 nm with 30-MHz repetition rate and 14.5-W average power (corresponding to 483-nJ pulse energy). We employ fiber-optic self-phase modulation (SPM) to broaden the laser spectrum and generate isolated spectral lobes. Filtering the rightmost spectral lobe leads to femtosecond pulses with >10 nJ pulse energy. Tunable between 1.1-1.2 μm, this SPM-enabled ultrafast source exhibits ∝100 times higher pulse energy than can be obtained from Raman soliton sources in this wavelength range. We use this SPM-enabled source as the signal beam and part of the Yb-fiber laser output as the pump beam. By performing DFG in GaSe crystals, we demonstrate that power scaling of a DFG-based mid-IR source can be efficiently achieved by increasing the signal energy. The resulting mid-IR source is tunable from 7.4 μm to 16.8 μm. Up to 5.04-mW mid-IR pulses centered at 11 μm are achieved. The corresponding pulse energy is 167 pJ, representing nearly one order of magnitude improvement compared with other reported DFG-based mid-IR sources at this wavelength. Despite of low pulse energy, Raman soliton sources have become a popular choice as the signal source. We carry out a detailed study on

Intermittent Rivers and Biodiversity. Large scale analyses between hydrology and ecology in intermittent rivers

OpenAIRE

Blanchard, Q.

2014-01-01

Intermittent rivers are characterized by a temporary interruption of their flow which can manifest in a variety of ways, as much on a spatial scale as on a temporal one. This particular aspect of intermittent river hydrology gives rise to unique ecosystems, combining both aquatic and terrestrial habitats. Neglected for a long time by scientists and once considered biologically depauperate and ecologically unimportant, these fragile habitats are nowadays acknowledged for their rendered service...

Market role, profitability and competitive features of thermal power plants in the Swedish future electricity market with high renewable integration

OpenAIRE

Llovera Bonmatí, Albert

2017-01-01

The Swedish energy market is currently undergoing a transition from fossil fuels to renewable energy sources, including a potential phase-out of nuclear power. The combination of a phase-out with expansion of intermittent renewable energy leads to the issue of increased fluctuations in electricity production. Energy-related organizations and institutions are projecting future Swedish energy scenarios with different possible transition pathways. In this study the market role of thermal power p...

Transition to turbulence via spatiotemporal intermittency in stimulated Raman backscattering

International Nuclear Information System (INIS)

Skoric, M.M.; Jovanovic, M.S.; Rajkovic, M.R.

1996-01-01

The spatiotemporal evolution of stimulated Raman backscattering in a bounded, uniform, weakly dissipative plasma is studied. The nonlinear model of a three-wave interaction involves a quadratic coupling of slowly varying complex amplitudes of the laser pump, the backscattered and the electron plasma wave. The corresponding set of coupled partial differential equations with nonlinear phase detuning that is taken into account is solved numerically in space time with fixed nonzero source boundary conditions. The study of the above open, convective, weakly confined system reveals a quasiperiodic transition to spatiotemporal chaos via spatiotemporal intermittency. In the analysis of transitions a dual scheme borrowed from fields of nonlinear dynamics and statistical physics is applied. An introduction of a nonlinear three-wave interaction to a growing family of paradigmatic equations which exhibit a route to turbulence via spatiotemporal intermittency is outlined in this work. copyright 1996 The American Physical Society

Benefits of coal-fired power generation with flexible CCS in a future northwest European power system with large scale wind power

NARCIS (Netherlands)

Van der Wijk, Pieter Cornelis; Brouwer, Anne Sjoerd|info:eu-repo/dai/nl/330822748; Van den Broek, Machteld|info:eu-repo/dai/nl/092946895; Slot, Thijs; Stienstra, Gerard; Van der Veen, Wim; Faaij, André P C

Coal-fired power generation with carbon capture and storage (CCS) is projected as a cost-effective technology to decarbonize the power sector. Intermittent renewables could reduce its load factor and revenues, so flexible capture unit operation strategies (flexible CCS) have been suggested to

Use assessment of electronic power sources for SMAW

Directory of Open Access Journals (Sweden)

Scotti, A.

1999-04-01

Full Text Available The aim of the present work was to assess the efficacy of the use of modern technologies for power supplies in Shielded Metal Are Welding (SMAW. Coupon tests were welded by using a series of five different classes of commercial electrodes, covering their current ranges. Both a conventional electromagnetic and an electronic (inverter power sources were employed. Fusion rate, deposition efficiency, bead finish and weld geometry were measured at each experiment. Current and voltage signals were acquired at a high rate to evaluate the dynamic behavior of the power sources. The static performances of both power sources were also determined. The results showed that despite the remarkable differences between the power supplies, based on static and dynamic characterizations, no significant difference was noticed in the operational behavior of the electrodes, in the given conditions, apart from a better anti-stick performance obtained with the electronic power source.

El objetivo del presente trabajo fue evaluar la eficacia del uso de tecnologías modernas para fuentes de energía en soldaduras con electrodo revestido (Shielded Metal Are Welding -SMAW-. Los materiales de ensayo se soldaron usando una serie de cinco clases diferentes de electrodos comerciales, cubriendo sus rangos de corriente. Para esto se utilizó una fuente de energía electromagnética convencional y una fuente de energía electrónica (inversora. La tasa de fusión, eficiencia de deposición, terminación del cordón así como el diseño de la soldadura se midieron en cada experimento. Las señales de corriente y voltaje se obtuvieron a una proporción alta para evaluar el comportamiento dinámico de las fuentes de energía. También se determinó la actuación estática de ambas fuentes. Los resultados mostraron que a pesar de las diferencias notables entre los suministros de energía, no se nota diferencia alguna significante en la conducta de trabajo de los electrodos, en

Intermittency in the Scrape-off Layer of the National Spherical Torus Experiment During H-mode Confinement

International Nuclear Information System (INIS)

Maqueda, R.J.; Stotler, D.P.; Zweben, S.J.

2010-01-01

A gas puff imaging diagnostic is used in the National Spherical Tokamak Experiment (M. Ono, et al., Nucl. Fusion 40, 557 (2000)) to study the edge turbulence and intermittency present during H-mode discharges. In the case of low power Ohmic H-modes the suppression of turbulence/blobs is maintained through the duration of the (short lived) H-modes. Similar quiescent edges are seen during the early stages of H-modes created with the use of neutral beam injection. Nevertheless, as time progresses following the L-H transition, turbulence and blobs reappear although at a lower level than that typically seen during L-mode confinement. It is also seen that the time-averaged SOL emission profile broadens, as the power loss across the separatrix increases. These broad profiles are characterized by a large level of fluctuations and intermittent events.

The intermittency of wind, solar, and renewable electricity generators. Technical barrier or rhetorical excuse?

Energy Technology Data Exchange (ETDEWEB)

Sovacool, Benjamin K. [Centre on Asia and Globalisation, Lee Kuan Yew School of Public Policy, National University of Singapore, 469C Bukit Timah Road, Singapore 259772 (Singapore)

2009-09-15

A consensus has long existed within the electric utility sector of the United States that renewable electricity generators such as wind and solar are unreliable and intermittent to a degree that they will never be able to contribute significantly to electric utility supply or provide baseload power. This paper asks three interconnected questions: (1) What do energy experts really think about renewables in the United States?; (2) To what degree are conventional baseload units reliable?; (3) Is intermittency a justifiable reason to reject renewable electricity resources? To provide at least a few answers, the author conducted 62 formal, semi-structured interviews at 45 different institutions including electric utilities, regulatory agencies, interest groups, energy systems manufacturers, nonprofit organizations, energy consulting firms, universities, national laboratories, and state institutions in the United States. In addition, an extensive literature review of government reports, technical briefs, and journal articles was conducted to understand how other countries have dealt with (or failed to deal with) the intermittent nature of renewable resources around the world. It was concluded that the intermittency of renewables can be predicted, managed, and mitigated, and that the current technical barriers are mainly due to the social, political, and practical inertia of the traditional electricity generation system. (author)

Putting intelligent structured intermittent auscultation (ISIA) into practice.

Science.gov (United States)

Maude, Robyn M; Skinner, Joan P; Foureur, Maralyn J

2016-06-01

Fetal monitoring guidelines recommend intermittent auscultation for the monitoring of fetal wellbeing during labour for low-risk women. However, these guidelines are not being translated into practice and low-risk women birthing in institutional maternity units are increasingly exposed to continuous cardiotocographic monitoring, both on admission to hospital and during labour. When continuous fetal monitoring becomes routinised, midwives and obstetricians lose practical skills around intermittent auscultation. To support clinical practice and decision-making around auscultation modality, the intelligent structured intermittent auscultation (ISIA) framework was developed. The purpose of this discussion paper is to describe the application of intelligent structured intermittent auscultation in practice. The intelligent structured intermittent auscultation decision-making framework is a knowledge translation tool that supports the implementation of evidence into practice around the use of intermittent auscultation for fetal heart monitoring for low-risk women during labour. An understanding of the physiology of the materno-utero-placental unit and control of the fetal heart underpin the development of the framework. Intelligent structured intermittent auscultation provides midwives with a robust means of demonstrating their critical thinking and clinical reasoning and supports their understanding of normal physiological birth. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Intermittent Astrophysical Radiation Sources and Terrestrial Life

Science.gov (United States)

Melott, Adrian

2013-04-01

Terrestrial life is exposed to a variety of radiation sources. Astrophysical observations suggest that strong excursions in cosmic ray flux and spectral hardness are expected. Gamma-ray bursts and supernovae are expected to irradiate the atmosphere with keV to GeV photons at irregular intervals. Supernovae will produce large cosmic ray excursions, with time development varying with distance from the event. Large fluxes of keV to MeV protons from the Sun pose a strong threat to electromagnetic technology. The terrestrial record shows cosmogenic isotope excursions which are consistent with major solar proton events, and there are observations of G-stars suggesting that the rate of such events may be much higher than previously assumed. In addition there are unknown and unexplained astronomical transients which may indicate new classes of events. The Sun, supernovae, and gamma-ray bursts are all capable of producing lethal fluences, and some are expected on intervals of 10^8 years or so. The history of life on Earth is filled with mass extinctions at a variety of levels of intensity. Most are not understood. Astrophysical radiation may play a role, particularly from large increases in muon irradiation on the ground, and changes in atmospheric chemistry which deplete ozone, admitting increased solar UVB. UVB is strongly absorbed by DNA and proteins, and breaks the chemical bonds---it is a known carcinogen. High muon fluxes will also be damaging to such molecules, but experiments are needed to pin down the rate. Solar proton events which are not directly dangerous for the biota may nevertheless pose a major threat to modern electromagnetic technology through direct impact on satellites and magnetic induction of large currents in power grids, disabling transformers. We will look at the kind of events that are expected on timescales from human to geological, and their likely consequences.

Measurement and diagnosis system for 1.2 MV repetitive pulsed power source

International Nuclear Information System (INIS)

Li Yawei; Deng Jianjun; Xie Min; Feng Zongming; Liu Yuntao; Ma Chenggang

2010-01-01

In order to analyze the discharge performance and improve the design of the power system, a set of measurement and diagnosis system for the 1.2 MV repetitive pulsed power source, which supplies the drive power for a high power microwave source, has been designed by studying the high-voltage, high-current testing technology, data acquisition, signal processing, fault diagnosis, virtual instruments and electromagnetic compatibility technology, etc. A resistive-capacitive divider and a Rogowski coil are adopted in measurement; ADLINK corporation's PXI chips are used in data acquisition; data transmission system, condition monitoring and data analysis are developed by LabVIEW. This system can realize on-line monitoring and data analysis for the repetitive pulsed power source. (authors)

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.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance.

Science.gov (United States)

Baker, Lindsay B; Rollo, Ian; Stein, Kimberly W; Jeukendrup, Asker E

2015-07-14

Intermittent sports (e.g., team sports) are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1-2 h). Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1) potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2) the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3) what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports). Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30-60 g/h in the form of a 6%-7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before and during a game

High-resolution modeling of the western North American power system demonstrates low-cost and low-carbon futures

International Nuclear Information System (INIS)

Nelson, James; Johnston, Josiah; Mileva, Ana; Fripp, Matthias; Hoffman, Ian; Petros-Good, Autumn; Blanco, Christian; Kammen, Daniel M.

2012-01-01

Decarbonizing electricity production is central to reducing greenhouse gas emissions. Exploiting intermittent renewable energy resources demands power system planning models with high temporal and spatial resolution. We use a mixed-integer linear programming model – SWITCH – to analyze least-cost generation, storage, and transmission capacity expansion for western North America under various policy and cost scenarios. Current renewable portfolio standards are shown to be insufficient to meet emission reduction targets by 2030 without new policy. With stronger carbon policy consistent with a 450 ppm climate stabilization scenario, power sector emissions can be reduced to 54% of 1990 levels by 2030 using different portfolios of existing generation technologies. Under a range of resource cost scenarios, most coal power plants would be replaced by solar, wind, gas, and/or nuclear generation, with intermittent renewable sources providing at least 17% and as much as 29% of total power by 2030. The carbon price to induce these deep carbon emission reductions is high, but, assuming carbon price revenues are reinvested in the power sector, the cost of power is found to increase by at most 20% relative to business-as-usual projections. - Highlights: ► Intermittent generation necessitates high-resolution electric power system models. ► We apply the SWITCH planning model to the western North American grid. ► We explore carbon policy and resource cost scenarios through 2030. ► As the carbon price rises, coal generation is replaced with solar, wind, gas and/or nuclear generation ► A 450 ppm climate stabilization target can be met at a 20% or lower cost increase.

Integrating wind power in EU electricity systems. Economic and technical issues

International Nuclear Information System (INIS)

Van Werven, M.J.N.; Beurskens, L.W.M.; Pierik, J.T.G.

2005-02-01

In view of the ongoing process of liberalisation of the electricity market and the expected increase of wind power pursuant the RES-E Directive (Renewable Energy Sources - Electricity) and the need to minimise the costs of the RES-E targets, this study discusses the technical and economic impacts of integrating wind power into the electricity system. Furthermore, two options for reducing costs of intermittency are researched: forecasting of wind power output and electricity storage. An increasing penetration of wind power into the electricity system causes additional costs, partly due to the fact that the energy source of wind power is uncontrollable, variable (on the short term as well as on the longer term), and unpredictable (especially on the longer term). Consequently, balancing generation and demand becomes more complicated, creating a need for additional secondary and tertiary control. Although the sources of increasing costs are becoming more clearly understood, as are means to mitigate them, the quantification of costs of operating an electricity system with high wind penetration is very hard. Two possible options to reduce costs of intermittency are discussed in this report: forecasting of wind power output and electricity storage. The need for and benefit of wind energy forecasting have been increasingly recognised in recent years. Forecasting of wind power directs on increasing the predictability of the resource and improved forecasting can help to enhance the balancing of supply and demand. DG (distributed generation) operators can provide better information about their expected power output, energy suppliers can submit better estimates of electricity production to the TSO (Transmission System Operator), and system operators can improve network management through better information about expected power flows. Electricity storage systems can, at the same time, offer different services to a number of actors. Next to benefits that result from price

Hybrid Microgrid Model based on Solar Photovoltaics with Batteries and Fuel Cells system for intermittent applications

Science.gov (United States)

Patterson, Maxx

Microgrids are a subset of the modern power structure; using distributed generation (DG) to supply power to communities rather than vast regions. The reduced scale mitigates loss allowing the power produced to do more with better control, giving greater security, reliability, and design flexibility. This paper explores the performance and cost viability of a hybrid grid-tied microgrid that utilizes Photovoltaic (PV), batteries, and fuel cell (FC) technology. The concept proposes that each community home is equipped with more PV than is required for normal operation. As the homes are part of a microgrid, excess or unused energy from one home is collected for use elsewhere within the microgrid footprint. The surplus power that would have been discarded becomes a community asset, and is used to run intermittent services. In this paper, the modeled community does not have parking adjacent to each home allowing for the installment of a privately owned slower Level 2 charger, making EV ownership option untenable. A solution is to provide a Level 3 DC Quick Charger (DCQC) as the intermittent service. The addition of batteries and Fuel Cells are meant to increase load leveling, reliability, and instill limited island capability.

Coherent Structures and Intermittency in Plasma Turbulence

International Nuclear Information System (INIS)

Das, Amita; Kaw, Predhiman; Sen, Abhijit

2008-01-01

The paper discusses some fundamental issues related to the phenomenon of intermittency in plasma turbulence with particular reference to experimental observations in fusion devices. Intermittency is typically associated with the presence of coherent structures in turbulence. Since coherent structures can play an important role in governing the transport properties of a system they have received a great deal of attention in fusion research. We review some of the experimental measurements and numerical simulation studies on the presence and formation of coherent structures in plasmas and discuss their relevance to intermittency. Intermittency, as widely discussed in the context of neutral fluid turbulence, implies multiscaling behaviour in contrast to self-similar scaling patterns observed in self organized criticality (SOC) phenomenon. The experimental evidence from plasma turbulence measurements reveal a mixed picture--while some observations support the SOC model description others indicate the presence of multiscaling behaviour. We discuss these results in the light of our present understanding of plasma turbulence and in terms of certain unique aspects of intermittency as revealed by fluid models of plasmas.

The impact of intermittent or sustained carbon dioxide on intermittent hypoxia initiated respiratory plasticity. What is the effect of these combined stimuli on apnea severity?

Science.gov (United States)

Mateika, Jason H; Panza, Gino; Alex, Raichel; El-Chami, Mohamad

2017-10-31

The following review explores the effect that intermittent or sustained hypercapnia coupled to intermittent hypoxia has on respiratory plasticity. The review explores published work which suggests that intermittent hypercapnia leads to long-term depression of respiration when administered in isolation and prevents the initiation of long-term facilitation when administered in combination with intermittent hypoxia. The review also explores the impact that sustained hypercapnia alone and in combination with intermittent hypoxia has on the magnitude of long-term facilitation. After exploring the outcomes linked to intermittent hypoxia/hypercapnia and intermittent hypoxia/sustained hypercapnia the translational relevance of the outcomes as it relates to breathing stability during sleep is addressed. The likelihood that naturally induced cycles of intermittent hypoxia, coupled to oscillations in carbon dioxide that range between hypocapnia and hypercapnia, do not initiate long-term facilitation is addressed. Moreover, the conditions under which intermittent hypoxia/sustained hypercapnia could serve to improve breathing stability and mitigate co-morbidities associated with sleep apnea are considered. Published by Elsevier B.V.

Energy control of supercapacitor/fuel cell hybrid power source

International Nuclear Information System (INIS)

Payman, Alireza; Pierfederici, Serge; Meibody-Tabar, Farid

2008-01-01

This paper deals with a flatness based control principle in a hybrid system utilizing a fuel cell as a main power source and a supercapacitor as an auxiliary power source. The control strategy is based on regulation of the dc bus capacitor energy and, consequently, voltage regulation. The proposed control algorithm does not use a commutation algorithm when the operating mode changes with the load power variation and, thus, avoids chattering effects. Using the flatness based control method, the fuel cell dynamic and its delivered power is perfectly controlled, and the fuel cell can operate in a safe condition. In the hybrid system, the supercapacitor functions during transient energy delivery or during energy recovery situations. To validate the proposed method, the control algorithms are executed in dSPACE hardware, while analogical current loops regulators are employed in the experimental environment. The experimental results prove the validity of the proposed approach

Flexible and Cost Efficient Power Consumption using Economic MPC

DEFF Research Database (Denmark)

Hovgaard, Tobias Gybel; Larsen, Lars F.S.; Jørgensen, John Bagterp

2011-01-01

the formulation of a new cost function for our proposed power management. Hereby the refrigeration system is enabled to contribute with ancillary services to the balancing power market. Since significant amounts of regulating power is needed for a higher penetration of intermittent renewable energy sources...... such as wind turbines this feature is in high demand in a future intelligent power grid (Smart Grid). Our perspective is seen from the refrigeration system but as it is demonstrated the involvement in the balancing market can be economically beneficial for the system itself while delivering crucial services...... that reduces operation costs by utilizing the thermal storage capabilities. In the study we specifically address advantages coming from daily variations in outdoor temperature and electricity prices but other aims such as peak load reduction are also considered. An important contribution of this paper is also...

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.

Relation between source term and emergency planning for nuclear power plants

International Nuclear Information System (INIS)

Shi Zhongqi; Yang Ling

1992-01-01

Some background information of the severe accidents and source terms related to the nuclear power plant emergency planning are presented. The new source term information in NUREG-0956 and NUREG-1150, and possible changes in emergency planning requirements in U.S.A. are briefly provided. It is suggested that a principle is used in selecting source terms for establishing the emergency planning policy and a method is used in determining the Emergency Planning Zone (EPZ) size in China. Based on the research results of (1) EPZ size of PWR nuclear power plants being built in China, and (2) impact of reactor size and selected source terms on the EPZ size, it is concluded that the suggested principle and the method are suitable and feasible for PWR nuclear power plants in China

On-line measurement of the microwave power in ECR ion source

International Nuclear Information System (INIS)

Zhou Changgeng; Kang Wu; Hu Yonghong; Li Yan; Lou Benchao; Zu Xiulan; Xiong Riheng; Chen Junguang

2005-01-01

It is a new technology that ECR ion source is applied in the neutron generator. Because of effect of the structure, working state of ECR ion source could not be judged by the color of gas discharging in discharging chamber as doing in high frequency ion source. Therefore, state adjusting of ECR ion source was difficult in running of the neutron generator. The method to resolve the question is described in this paper. The micro-wave power was measured in case of running by using the method of directional coupler adding small microwave power meter. Because both were in the direct proportion, the ion beam current could be educed from microwave incidence power measured, and discharge state in discharge chamber could be judged. Finally, the neutron generator might be operated in best running state. (authors)

Intermittent hypoxia increases insulin resistance in genetically obese mice.

Science.gov (United States)

Polotsky, Vsevolod Y; Li, Jianguo; Punjabi, Naresh M; Rubin, Arnon E; Smith, Philip L; Schwartz, Alan R; O'Donnell, Christopher P

2003-10-01

Obstructive sleep apnoea, a syndrome that leads to recurrent intermittent hypoxia, is associated with insulin resistance in obese individuals, but the mechanisms underlying this association remain unknown. We utilized a mouse model to examine the effects of intermittent hypoxia on insulin resistance in lean C57BL/6J mice and leptin-deficient obese (C57BL/6J-Lepob) mice. In lean mice, exposure to intermittent hypoxia for 5 days (short term) resulted in a decrease in fasting blood glucose levels (from 173 +/- 11 mg dl-1 on day 0 to 138 +/- 10 mg dl-1 on day 5, P obese mice, short-term intermittent hypoxia led to a decrease in blood glucose levels accompanied by a 607 +/- 136 % (P intermittent hypoxia was completely abolished by prior leptin infusion. Obese mice exposed to intermittent hypoxia for 12 weeks (long term) developed a time-dependent increase in fasting serum insulin levels (from 3.6 +/- 1.1 ng ml-1 at baseline to 9.8 +/- 1.8 ng ml-1 at week 12, P intermittent hypoxia is dependent on the disruption of leptin pathways.

Increase of the positive ion source power in JT-60 NBI

International Nuclear Information System (INIS)

Kawai, Mikito; Akino, Noboru; Ebisawa, Noboru

1998-09-01

Neutral Beam Injection (NBI) heating experiment in JT-60 started in 1986, and the rated injection power of 20MW at 75keV with hydrogen was achieved after several month operation. In 1991, the ion sources and power supply had been upgraded for a higher beam energy up to 120keV with deuterium, following which the ion source operation re-started aiming for an injection power of 40MW at 110keV. In the operation, the beam acceleration voltage was tried to increase by modifying the ion source structure against the break-down which occurred frequently in the ion source. The beam acceleration was, however, unstable in a beam energy range of more than 105keV because of voltage-holding deterioration in the accelerator. Therefore we changed the strategy to increase the injection power: i.e. we tried to increase the beam current with keeping the beam energy. The structure of the source has been modified to be operated in a high current regime. As a result, the deuterium neutral beam injection of 40MW at 91-96keV was achieved in July 1996. (author)

Low Power Consumption Wireless Sensor Communication System Integrated with an Energy Harvesting Power Source

OpenAIRE

Vlad MARSIC; Alessandro GIULIANO; Meiling ZHU

2013-01-01

This paper presents the testing results of a wireless sensor communication system with low power consumption integrated with an energy harvesting power source. The experiments focus on the system’s capability to perform continuous monitoring and to wirelessly transmit the data acquired from the sensors to a user base station, for realization of completely battery-free wireless sensor system. Energy harvesting technologies together with system design optimization for power consumption minimiza...

Harvesting energy an sustainable power source, replace batteries for powering WSN and devices on the IoT

Science.gov (United States)

Pop-Vadean, A.; Pop, P. P.; Latinovic, T.; Barz, C.; Lung, C.

2017-05-01

Harvesting energy from nonconventional sources in the environment has received increased attention over the past decade from researchers who study these alternative energy sources for low power applications. Although that energy harvested is small and in the order of milliwatt, it can provide enough power for wireless sensors and other low-power applications. In the environment there is a lot of wasted energy that can be converted into electricity to power the various circuits and represents a potentially cheap source of power. Energy harvesting is important because it offers an alternative power supply for electronic devices where is does not exist conventional energy sources. This technology applied in a wireless sensor network (WSN) and devices on the IoT, will eliminate the need for network-based energy and conventional batteries, will minimize maintenance costs, eliminate cables and batteries and is ecological. It has the same advantage in applications from remote locations, underwater, and other hard to reach places where conventional batteries and energy are not suitable. Energy harvesting will promote environmentally friendly technologies that will save energy, will reduce CO2 emissions, which makes this technology indispensable for achieving next-generation smart cities and sustainable society. In response to the challenges of energy, in this article we remind the basics of harvesting energy and we discuss the various applications of this technology where traditional batteries cannot be used.

Google matrix and Ulam networks of intermittency maps.

Science.gov (United States)

Ermann, L; Shepelyansky, D L

2010-03-01

We study the properties of the Google matrix of an Ulam network generated by intermittency maps. This network is created by the Ulam method which gives a matrix approximant for the Perron-Frobenius operator of dynamical map. The spectral properties of eigenvalues and eigenvectors of this matrix are analyzed. We show that the PageRank of the system is characterized by a power law decay with the exponent beta dependent on map parameters and the Google damping factor alpha . Under certain conditions the PageRank is completely delocalized so that the Google search in such a situation becomes inefficient.

The Yo-Yo intermittent recovery test

DEFF Research Database (Denmark)

Bangsbo, Jens; Iaia, F. Marcello; Krustrup, Peter

2008-01-01

The two Yo-Yo intermittent recovery (IR) tests evaluate an individual's ability to repeatedly perform intense exercise. The Yo-Yo IR level 1 (Yo-Yo IR1) test focuses on the capacity to carry out intermittent exercise leading to a maximal activation of the aerobic system, whereas Yo-Yo IR level 2...

Dynamic characterizers of spatiotemporal intermittency

OpenAIRE

Gupte, Neelima; Jabeen, Zahera

2006-01-01

Systems of coupled sine circle maps show regimes of spatiotemporally intermittent behaviour with associated scaling exponents which belong to the DP class, as well as regimes of spatially intermittent behaviour (with associated regular dynamical behaviour) which do not belong to the DP class. Both types of behaviour are seen along the bifurcation boundaries of the synchronized solutions, and contribute distinct signatures to the dynamical characterizers of the system, viz. the distribution of...

A Chronological Reliability Model to Assess Operating Reserve Allocation to Wind Power Plants: Preprint

International Nuclear Information System (INIS)

Milligan, M. R.

2001-01-01

As the use of wind power plants increases worldwide, it is important to understand the effect these power sources have on the operations of the grid. This paper focuses on the operating reserve impact of wind power plants. Many probabilistic methods have been applied to power system analysis, and some of these are the basis of reliability analysis. This paper builds on a probabilistic technique to allocate the operating reserve burden among power plants in the grid. The method was originally posed by Strbac and Kirschen[1] and uses an allocation that prorates the reserve burden based on expected energy not delivered. Extending this method to include wind power plants allows the reserve burden to be allocated among different plants using the same method, yet incorporates information about the intermittent nature of wind power plants

Can renewable energy power the future?

International Nuclear Information System (INIS)

Moriarty, Patrick; Honnery, Damon

2016-01-01

Fossil fuels face resource depletion, supply security, and climate change problems; renewable energy (RE) may offer the best prospects for their long-term replacement. However, RE sources differ in many important ways from fossil fuels, particularly in that they are energy flows rather than stocks. The most important RE sources, wind and solar energy, are also intermittent, necessitating major energy storage as these sources increase their share of total energy supply. We show that estimates for the technical potential of RE vary by two orders of magnitude, and argue that values at the lower end of the range must be seriously considered, both because their energy return on energy invested falls, and environmental costs rise, with cumulative output. Finally, most future RE output will be electric, necessitating radical reconfiguration of existing grids to function with intermittent RE. - Highlights: •Published estimates for renewable energy (RE) technical potential vary 100-fold. •Intermittent wind and solar energy dominate total RE potential. •We argue it is unlikely that RE can meet existing global energy use. •The need to maintain ecosystem services will reduce global RE potential. •The need for storage of intermittent RE will further reduce net RE potential.

Acute Effects of Carbohydrate Supplementation on Intermittent Sports Performance

Directory of Open Access Journals (Sweden)

Lindsay B. Baker

2015-07-01

Full Text Available Intermittent sports (e.g., team sports are diverse in their rules and regulations but similar in the pattern of play; that is, intermittent high-intensity movements and the execution of sport-specific skills over a prolonged period of time (~1–2 h. Performance during intermittent sports is dependent upon a combination of anaerobic and aerobic energy systems, both of which rely on muscle glycogen and/or blood glucose as an important substrate for energy production. The aims of this paper are to review: (1 potential biological mechanisms by which carbohydrate may impact intermittent sport performance; (2 the acute effects of carbohydrate ingestion on intermittent sport performance, including intermittent high-intensity exercise capacity, sprinting, jumping, skill, change of direction speed, and cognition; and (3 what recommendations can be derived for carbohydrate intake before/during exercise in intermittent sports based on the available evidence. The most researched intermittent sport is soccer but some sport-specific studies have also been conducted in other sports (e.g., rugby, field hockey, basketball, American football, and racquet sports. Carbohydrate ingestion before/during exercise has been shown in most studies to enhance intermittent high-intensity exercise capacity. However, studies have shown mixed results with regards to the acute effects of carbohydrate intake on sprinting, jumping, skill, change of direction speed, and cognition. In most of these studies the amount of carbohydrate consumed was ~30–60 g/h in the form of a 6%–7% carbohydrate solution comprised of sucrose, glucose, and/or maltodextrin. The magnitude of the impact that carbohydrate ingestion has on intermittent sport performance is likely dependent on the carbohydrate status of the individual; that is, carbohydrate ingestion has the greatest impact on performance under circumstances eliciting fatigue and/or hypoglycemia. Accordingly, carbohydrate ingestion before

Electro-generating renewable energies: which potential by 2025/2030? The Ademe's scenario: is its treatment of the electric mix credible for the treatment of the intermittency of renewable energies, is its cost acceptable, are its consumption predictions realistic?

International Nuclear Information System (INIS)

Flocard, Hubert; Nifenecker, Herve; Perves, Jean Pierre

2012-01-01

This document proposes a critical point of view on the scenario developed by the ADEME on the potential of electricity production by renewable energies by 2025/2030. According to this scenario, nuclear power is divided by two and the fleet of intermittent renewable energies (wind and photovoltaic) is multiplied by seven. This report assesses the investments costs associated with this intermittent fleet and with a necessary adaptation of the high voltage and distribution grids. It also outlines that massive imports of energy could be necessary when the production of these renewable sources is at its low point. It notices that stopping half of the nuclear fleet will entail a loss of revenues which will not take benefit of a reduction of greenhouse gas

Analysis of isokinetic muscle function and postural control in individuals with intermittent claudication

Directory of Open Access Journals (Sweden)

Morgan Lanzarin

2016-02-01

Full Text Available BACKGROUND: Intermittent claudication (IC is a debilitating condition that mostly affects elderly people. IC is manifested by a decrease in ambulatory function. Individuals with IC present with motor and sensory nerve dysfunction in the lower extremities, which may lead to deficits in balance. OBJECTIVE: This study aimed to measure postural control and isokinetic muscle function in individuals with intermittent claudication. METHOD: The study included 32 participants of both genders, 16 IC participants (mean age: 64 years, SD=6 and 16 healthy controls (mean age: 67 years, SD=5, which were allocated into two groups: intermittent claudication group (ICG and control group (CG. Postural control was assessed using the displacement and velocity of the center of pressure (COP during the sensory organization test (SOT and the motor control test (MCT. Muscle function of the flexor and extensor muscles of the knee and ankle was measured by an isokinetic dynamometer. Independent t tests were used to calculate the between-group differences. RESULTS: The ICG presented greater displacement (p =0.027 and speed (p =0.033 of the COP in the anteroposterior direction (COPap during the MCT, as well as longer latency (p =0.004. There were no between-group differences during the SOT. The ICG showed decreased muscle strength and power in the plantar flexors compared to the CG. CONCLUSION: Subjects with IC have lower values of strength and muscle power of plantiflexores, as well as changes in postural control in dynamic conditions. These individuals may be more vulnerable to falls than healthy subjects.

The impact of turbulent renewable energy production on power grid stability and quality

Science.gov (United States)

Schmietendorf, Katrin; Peinke, Joachim; Kamps, Oliver

2017-11-01

Feed-in fluctuations induced by renewables are one of the key challenges to the stability and quality of electrical power grids. In particular short-term fluctuations disturb the system on a time scale, on which load balancing does not operate yet and the system is intrinsically governed by self-organized synchronization. Wind and solar power are known to be strongly non-Gaussian with intermittent increment statistics in these time scales. We investigate the impact of short-term wind fluctuations on the basis of a Kuramoto-like power grid model considering stability in terms of desynchronization and frequency and voltage quality aspects. We present a procedure to generate realistic feed-in fluctuations with temporal correlations, Kolmogorov power spectrum and intermittent increments. By comparison to correlated Gaussian noise of the same spectrum and Gaussian white noise, we found out that while the correlations are essential to capture the likelihood of severe outages, the intermittent nature of wind power has significant consequences on power quality: intermittency is directly transferred into frequency and voltage fluctuations yielding a novel type of fluctuations, which is beyond engineering status of knowledge.

Modern batteries an introduction to electrochemical power sources

CERN Document Server

Vincent, C

2003-01-01

Based on the successful first edition, this book gives a general theoretical introduction to electrochemical power cells (excluding fuel cells) followed by a comprehensive treatment of the principle battery types - covering chemistry, fabrication characteristics and applications. There have been many changes in the field over the last decade and many new systems have been commercialised. Since the recent advent of battery powered consumer products (mobile phones, camcorders, lap-tops etc.) advanced power sources have become far more important. This text provides an up-to-date account of batter

Low stored energy 100 kV regulator for ion sources at LANSCE

International Nuclear Information System (INIS)

Jacobson, E.G.; Haffner, R.L.; Ingalls, W.B.; Meyer, B.J.; Stelzer, J.E.

1998-01-01

To minimize accelerating column damage caused by uncontrolled energy release during arc-downs, it is desirable to minimize the available stored electrical energy. For the Los Alamos Neutron Science Center (LANSCE) H - ion sources, the stored energy includes, in addition to the charge in the power supply output capacitance, the charge on the electronics racks. They are supported and insulated from ground by PVC pipe and have a capacitance to ground of approximately 900 pf. In 1988 (LANSCE) personnel designed a high-voltage current source using a low-stored-energy power supply and planar triode with the goal of eliminating uncontrolled release of charge stored in the power supply. Construction and testing were performed intermittently as resources permitted until 1993. When work on the Short Pulse Spallation Source (SPSS) started on the LANSCE Ion Source Test Stand (ISTS) it was recognized that a higher current power supply would be needed and work resumed on the regulator circuitry. A 120 kV power supply having low output capacitance, and a planar triode have been used to supply 40 mA, 120 Hz, 12% duty-factor current for the ISTS beam. The triode's cathode current is controlled by circuitry operating both at power-supply voltage level and at ground level via a fiber optic link. Voltage droop is approximately 600 V during the 1 ms beam pulse. The authors present the status of the regulator and its special challenges

Long-term program up to fiscal 1993 of electric power source development

International Nuclear Information System (INIS)

Kawakami, Shin-ichi

1984-01-01

The long-term, ten years, program up to fiscal 1993 of electric power source development, determined by the Government aims at stable power supply and the expansion of utilization of petroleum-substitute energy. The annual growth in the gross national product (GNP) during the ten years was taken as about 4 %. So, the total electric power demand in fiscal 1993 is scheduled to be 731,000 million kwh, about 34 % up from 547,000 million kwh in fiscal 1983. The structure of electric power sources at the end of fiscal 1993 will be hydraulic 19.7 %, thermal 58.3 %, and nuclear 21.9 %. The development of electric power sources to be initiated in fiscal 1984 is hydraulic 500 MW, thermal 2,000 MW, and nuclear 6,000 MW. (Mori, K.)

Urban community perception towards intermittent water supply system.

Science.gov (United States)

Joshi, M W; Talkhande, A V; Andey, S P; Kelkar, P S

2002-04-01

While evaluating intermittent and continuous water supply systems, consumers opinion survey was undertaken for critical appraisal of both modes of operation. With the help of a pre-designed set of questions relating to various aspects of water supply and the opinion of consumers regarding degree of service, a house to house survey was conducted in the study area of Ghaziabad and Jaipur. The consumer opinion survey clearly indicated a satisfactory degree of service wherever adequate quantity of water was made available irrespective of the mode of water supply. Number of complaints regarding quality of water supplied, timings of supply, low pressures and breakdowns in supply were reported during intermittent water supply. Every family stored water for drinking and other uses. Most of the families discard drinking water once the fresh water supply is resumed next day. Discarded drinking water is usually used in kitchen for washing and gardening. Storage for other purposes depends on economic status and availability of other sources like open dug well in the house. While most of the respondents had no complaints on water tariff, all of them were in favour of continuous water supply.

New sources of high-power coherent radiation

International Nuclear Information System (INIS)

Sprehngl, F.

1985-01-01

New sources of high-power coherent radiation in the wavelength range from millimeter to ultraviolet are reviewed. Physical mechanisms underlying concepts of free electrons laser, cyclotron resonance laser and other new radiation sources are described. Free electron lasers and cyclotron resonance lasers are shown to suggest excellent possibilities for solving problems of spectroscopy, plasma heating radar and accelerator technology. Results of experiments with free electron laser in the Compton mode using linear accelerators microtrons and storage rings are given. Trends in further investigations are shown

Energy Efficient Refrigeration and Flexible Power Consumption in a Smart Grid

DEFF Research Database (Denmark)

Hovgaard, Tobias Gybel; Halvgaard, Rasmus; Larsen, Lars F.S.

2011-01-01

. With modern Economic Model Predictive Control (MPC) methods we make use of weather forecasts and predictions of varying electricity prices to apply more load to the system when the thermodynamic cycle is most efficient, and to consume larger shares of the electricity when the demand and thereby the prices...... are low. The ability to adjust power consumption according to the demands on the power grid is a highly wanted feature in a future Smart Grid. Efficient utilization of greater amounts of renewable energy calls for solutions to control the power consumption such that it increases when an energy surplus...... is available and decreases when there is a shortage. This should happen almost instantly to accommodate intermittent energy sources as e.g. wind turbines. We expect our power management solution to render systems with thermal storage capabilities suitable for flexible power consumption. The aggregation...

Intermittent cranial lung herniation in two dogs.

Science.gov (United States)

Guglielmini, Carlo; De Simone, Antonio; Valbonetti, Luca; Diana, Alessia

2007-01-01

Two aged dogs with chronic obstructive airway disease were evaluated because of intermittent swelling of the ventral cervical region. Radiographs made at expiration and caudal positioning of the forelimbs allowed identification of intermittent cervical lung herniation of the left and right cranial lung lobe in both dogs. Pulmonary hyperinflation, increased expiratory effort, and chronic coughing were considered responsible for the lung herniation. Cervical lung hernia should be included in the differential diagnoses of intermittent cervical swelling in dogs with chronic respiratory disorders associated with increased expiratory effort and chronic coughing.

Microcontroller based implementation of fuel cell and battery integrated hybrid power source

International Nuclear Information System (INIS)

Fahad, A.; Ali, S.M.; Bhatti, A.A.; Nasir, M

2013-01-01

This paper presents the implementation of a digitally controlled hybrid power source system, composed of fuel cell and battery. Use of individual fuel cell stacks as a power source, encounters many problems in achieving the desired load characteristics. A battery integrated, digitally controlled hybrid system is proposed for high pulse requirements. The proposed hybrid power source fulfils these peak demands with efficient flow of energy as compared to individual operations of fuel cell or battery system. A dc/dc converter is applied which provides an optimal control of power flow among fuel cell, battery and load. The proposed system efficiently overcomes the electrochemical constraints like over current, battery leakage current, and over and under voltage dips. By formulation of an intelligent algorithm and incorporating a digital technology (AVR Microcontroller), an efficient control is achieved over fuel cell current limit, battery charge, voltage and current. The hybrid power source is tested and analyzed by carrying out simulations using MATLAB simulink. Along with the attainment of desired complex load profiles, the proposed design can also be used for power enhancement and optimization for different capacities. (author)

Robust power spectral estimation for EEG data.

Science.gov (United States)

Melman, Tamar; Victor, Jonathan D

2016-08-01

Typical electroencephalogram (EEG) recordings often contain substantial artifact. These artifacts, often large and intermittent, can interfere with quantification of the EEG via its power spectrum. To reduce the impact of artifact, EEG records are typically cleaned by a preprocessing stage that removes individual segments or components of the recording. However, such preprocessing can introduce bias, discard available signal, and be labor-intensive. With this motivation, we present a method that uses robust statistics to reduce dependence on preprocessing by minimizing the effect of large intermittent outliers on the spectral estimates. Using the multitaper method (Thomson, 1982) as a starting point, we replaced the final step of the standard power spectrum calculation with a quantile-based estimator, and the Jackknife approach to confidence intervals with a Bayesian approach. The method is implemented in provided MATLAB modules, which extend the widely used Chronux toolbox. Using both simulated and human data, we show that in the presence of large intermittent outliers, the robust method produces improved estimates of the power spectrum, and that the Bayesian confidence intervals yield close-to-veridical coverage factors. The robust method, as compared to the standard method, is less affected by artifact: inclusion of outliers produces fewer changes in the shape of the power spectrum as well as in the coverage factor. In the presence of large intermittent outliers, the robust method can reduce dependence on data preprocessing as compared to standard methods of spectral estimation. Copyright © 2016 Elsevier B.V. All rights reserved.

Electric Power From Ambient Energy Sources

Energy Technology Data Exchange (ETDEWEB)

DeSteese, John G.; Hammerstrom, Donald J.; Schienbein, Lawrence A.

2000-10-03

This report summarizes research on opportunities to produce electric power from ambient sources as an alternative to using portable battery packs or hydrocarbon-fueled systems in remote areas. The work was an activity in the Advanced Concepts Project conducted by Pacific Northwest National Laboratory (PNNL) for the Office of Research and Development in the U.S. Department of Energy Office of Nonproliferation and National Security.

Beneficial effects of intermittent suction and pressure treatment in intermittent claudication

DEFF Research Database (Denmark)

Mehlsen, J; Himmelstrup, H; Himmelstrup, Bodil

1993-01-01

administration. The treatment caused significant increments in the ADP thresholds for platelet aggregation, while the effects on fibrinolysis were uncertain. It is concluded that intermittent suction and pressure treatment offers a new approach for conservative treatment of intermittent claudication....... participated in an open trial investigating the possible effects of the treatment on platelet aggregation and fibrinolysis. Pain-free and maximal walking distances were measured on a treadmill, and systolic blood pressure was measured on the upper limb, the ankle, and the first toe bilaterally. The threshold...... for adenosine diphosphate (ADP)-induced platelet aggregation was tested, and the fibrinolytic activity was estimated from the euglobulin clot lysis time. Active treatment resulted in significant improvements in pain-free and maximal walking distances, whereas no changes could be found during placebo...

Morphology and power of radio sources

International Nuclear Information System (INIS)

Scheuer, P.A.G.

1982-01-01

The author discusses two points: 1. Observations suggest that the hot-spots move about either because the beam precesses or more discontinuously, as in sources like 3C351 that have multiple hot-spots. The natural interpretation is that the hot-spot at the end of the beam slides over the inner surface of a 'cavity' filled with very hot dilute ex-hot-spot material, extending the cavity at various places at different times. 2. Most of the radio emission of most really powerful radio sources comes from their hot spots. Contrariwise, straightforward equipartition calculations on models lead to at least as much emission from the 'cavity' as from the hot-spots. (Auth.)

Implementation of 252Cf-source-driven power spectrum density measurement system

International Nuclear Information System (INIS)

Ren Yong; Wei Biao; Feng Peng; Li Jiansheng; Ye Cenming

2012-01-01

The principle of 252 Cf-source-driven power spectrum density measurement method is introduced. A measurement system and platform is realized accordingly, which is a combination of hardware and software, for measuring nuclear parameters. The detection method of neutron pulses based on an ultra-high-speed data acquisition card (three channels, 1 GHz sampling rate, 1 ns synchronization) is described, and the data processing process and the power spectrum density algorithm on PC are designed. This 252 Cf-source-driven power spectrum density measurement system can effectively obtain the nuclear tag parameters of nuclear random processes, such as correlation function and power spectrum density. (authors)

Intermittency and random matrices

Science.gov (United States)

Sokoloff, Dmitry; Illarionov, E. A.

2015-08-01

A spectacular phenomenon of intermittency, i.e. a progressive growth of higher statistical moments of a physical field excited by an instability in a random medium, attracted the attention of Zeldovich in the last years of his life. At that time, the mathematical aspects underlying the physical description of this phenomenon were still under development and relations between various findings in the field remained obscure. Contemporary results from the theory of the product of independent random matrices (the Furstenberg theory) allowed the elaboration of the phenomenon of intermittency in a systematic way. We consider applications of the Furstenberg theory to some problems in cosmology and dynamo theory.

Modeling generalized interline power-flow controller (GIPFC using 48-pulse voltage source converters

Directory of Open Access Journals (Sweden)

Amir Ghorbani

2018-05-01

Full Text Available Generalized interline power-flow controller (GIPFC is one of the voltage-source controller (VSC-based flexible AC transmission system (FACTS controllers that can independently regulate the power-flow over each transmission line of a multiline system. This paper presents the modeling and performance analysis of GIPFC based on 48-pulsed voltage-source converters. This paper deals with a cascaded multilevel converter model, which is a 48-pulse (three levels voltage source converter. The voltage source converter described in this paper is a harmonic neutralized, 48-pulse GTO converter. The GIPFC controller is based on d-q orthogonal coordinates. The algorithm is verified using simulations in MATLAB/Simulink environment. Comparisons between unified power flow controller (UPFC and GIPFC are also included. Keywords: Generalized interline power-flow controller (GIPFC, Voltage source converter (VCS, 48-pulse GTO converter

Intermittent behavior of the logistic system

Science.gov (United States)

Mayer-Kress, G.; Haken, H.

1981-03-01

In the discrete logistic model a transition to chaotic behavior via intermittency occurs in a neighborhood of periodic bands. Intermittent behavior is also induced if a stable periodic orbit is perturbed by low-level external noise, whereas alterations due to computer digitalisation produce remarkable periodicities. We compare our numerical results with the predictions of Pomeau and Manneville for the Lorenz system.

A Method for Harmonic Sources Detection based on Harmonic Distortion Power Rate

Science.gov (United States)

Lin, Ruixing; Xu, Lin; Zheng, Xian

2018-03-01

Harmonic sources detection at the point of common coupling is an essential step for harmonic contribution determination and harmonic mitigation. The harmonic distortion power rate index is proposed for harmonic source location based on IEEE Std 1459-2010 in the paper. The method only based on harmonic distortion power is not suitable when the background harmonic is large. To solve this problem, a threshold is determined by the prior information, when the harmonic distortion power is larger than the threshold, the customer side is considered as the main harmonic source, otherwise, the utility side is. A simple model of public power system was built in MATLAB/Simulink and field test results of typical harmonic loads verified the effectiveness of proposed method.

RENEWABLE ENERGY SOURCES IN ELECTRIC-POWER IN-DUSTRY OF BELARUS

Directory of Open Access Journals (Sweden)

M. M. Oleshkevich

2014-01-01

Full Text Available The paper investigates technical and economic indices (specific capital inputs, construction period, pay-off period, possible economically substantiated generation of electric power of electric power plants using renewable energy sources under climatic conditions ofBelarus. The indices have been compared with the data of nuclear power engineering. The most efficient directions are wind and biomass power engineering. In accordance with its technical and economic and ecological indices the biomass power engineering is more profitable than nuclear, hydro- and solar power engineering.

Optical arc sensor using energy harvesting power source

Energy Technology Data Exchange (ETDEWEB)

Choi, Kyoo Nam, E-mail: knchoi@inu.ac.kr; Rho, Hee Hyuk, E-mail: rdoubleh0902@inu.ac.kr [Dept. of Information and Telecommunication Engineering Incheon National University Incheon 22012 (Korea, Republic of)

2016-06-03

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17 J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

Optical arc sensor using energy harvesting power source

Science.gov (United States)

Choi, Kyoo Nam; Rho, Hee Hyuk

2016-06-01

Wireless sensors without external power supply gained considerable attention due to convenience both in installation and operation. Optical arc detecting sensor equipping with self sustaining power supply using energy harvesting method was investigated. Continuous energy harvesting method was attempted using thermoelectric generator to supply standby power in micro ampere scale and operating power in mA scale. Peltier module with heat-sink was used for high efficiency electricity generator. Optical arc detecting sensor with hybrid filter showed insensitivity to fluorescent and incandescent lamps under simulated distribution panel condition. Signal processing using integrating function showed selective arc discharge detection capability to different arc energy levels, with a resolution below 17J energy difference, unaffected by bursting arc waveform. The sensor showed possibility for application to arc discharge detecting sensor in power distribution panel. Also experiment with proposed continuous energy harvesting method using thermoelectric power showed possibility as a self sustainable power source of remote sensor.

Statement on Wind Power

Energy Technology Data Exchange (ETDEWEB)

2010-01-15

Wind power will grow in importance in future electricity supply. In the next few decades it will to some degree replace fossil power but it will, at the same time also depend on fossil-b beyond, when wind power is expected to have a substantial share of the electricity market, CO{sub 2} emission-free electricity plants that are well suited for balancing the wind intermittency will be required. Predictions of the future penetration of wind power into the electricity market are critically dependent on a number of policy measures and will be especially influenced by climate driven energy policies. Very large investments will also be necessary as is shown by the lEA's Blue Map Scenario which includes 5,000 TWh wind electricity by 2050 at a cost of USD 700 billion. This implies an average 8% increase of wind electricity per year energy system, i.e. an energy system so large that it affects the entire world. The Energy Committee's scenario for electricity production in the year 2050 includes 5,000 TWh wind electricity out of a total of 45,000 TWh. Wind electricity thus has a within presently reached penetration of wind energy in a single country and within the calculated future projections of its penetration. Future large continental and intercontinental power grids may enable higher penetrations of wind energy since contributions of wind power from a larger area will tend to reduce its intermittency. Also, large-scale storage systems (thermal storage as is intermittent power systems. These alternatives have been discussed from a technical point of view [3] but for the required large-scale systems, further studies on the social, environmental and economical implications are needed

Intermittent hydronephrosis

International Nuclear Information System (INIS)

Knop, J.; Vogel, H.; Hupe, W.

1981-01-01

An intermittent hydronephrosis was observed in a 40-year old patient. This disease pattern is due to an incongruity between the formation of urine and the transport capacity in the ureteropelvic junction. The latent impediment of flow becomes manifest with increased urine secretion. Irreversible renal damage can be the result of the repeatedly occurring hydronephrotic crises. (orig.) [de

Stochastic model of wind-fuel cell for a semi-dispatchable power generation

DEFF Research Database (Denmark)

Alvarez-Mendoza, Fernanda; Bacher, Peder; Madsen, Henrik

2017-01-01

electrolyte membrane fuel cell, which are embedded in one complete system with the wind power. This study uses historic wind speed data from Mexico; the forecasts are obtained using the recursive least square algorithm with a forgetting factor. The proposed approach provides probabilistic information......Hybrid systems are implemented to improve the efficiency of individual generation technologies by complementing each other. Intermittence is a challenge to overcome especially for renewable energy sources for electric generation, as in the case of wind power. This paper proposes a hybrid system...... for short-term wind power generation and electric generation as the outcome of the hybrid system. A method for a semi-dispatchable electric generation based on time series analysis is presented, and the implementation of wind power and polymer electrolyte membrane fuel cell models controlled by a model...

Intermittent fasting protects against the deterioration of cognitive function, energy metabolism and dyslipidemia in Alzheimer's disease-induced estrogen deficient rats.

Science.gov (United States)

Shin, Bae Kun; Kang, Suna; Kim, Da Sol; Park, Sunmin

2018-02-01

Intermittent fasting may be an effective intervention to protect against age-related metabolic disturbances, although it is still controversial. Here, we investigated the effect of intermittent fasting on the deterioration of the metabolism and cognitive functions in rats with estrogen deficiency and its mechanism was also explored. Ovariectomized rats were infused with β-amyloid (25-35; Alzheimer's disease) or β-amyloid (35-25, Non-Alzheimer's disease; normal cognitive function) into the hippocampus. Each group was randomly divided into two sub-groups: one with intermittent fasting and the other fed ad libitum: Alzheimer's disease-ad libitum, Alzheimer's disease-intermittent fasting, Non-Alzheimer's disease-ad libitum, and Non-Alzheimer's disease-intermittent fasting. Rats in the intermittent fasting groups had a restriction of food consumption to a 3-h period every day. Each group included 10 rats and all rats fed a high-fat diet for four weeks. Interestingly, Alzheimer's disease increased tail skin temperature more than Non-Alzheimer's disease and intermittent fasting prevented the increase. Alzheimer's disease reduced bone mineral density in the spine and femur compared to the Non-Alzheimer's disease, whereas bone mineral density in the hip and leg was reduced by intermittent fasting. Fat mass only in the abdomen was decreased by intermittent fasting. Intermittent fasting decreased food intake without changing energy expenditure. Alzheimer's disease increased glucose oxidation, whereas intermittent fasting elevated fat oxidation as a fuel source. Alzheimer's disease and intermittent fasting deteriorated insulin resistance in the fasting state but intermittent fasting decreased serum glucose levels after oral glucose challenge by increasing insulin secretion. Alzheimer's disease deteriorated short and spatial memory function compared to the Non-Alzheimer's disease, whereas intermittent fasting prevented memory loss in comparison to ad libitum. Unexpectedly

Intermittency, avalanche statistics, and long-term correlations in a turbulent plasma

International Nuclear Information System (INIS)

Castellanos, Omar; Sentíes, José M; Anabitarte, Ernesto; López, Juan M

2013-01-01

We study the turbulent dynamics of a helium plasma in a non-confining cylindrical configuration. Our experimental setup allows us to analyze particle transport in different plasma regions. We find that, whereas the transport is diffusive in the innermost regions of the plasma, distinctive non-diffusive features appear in regions away from the center. Indeed, at the plasma edge we find that particle flux exhibits a power-law distribution of avalanche durations, intermittency, and long-term correlations. (paper)

An Emulated PV Source Based on an Unilluminated Solar Panel and DC Power Supply

Directory of Open Access Journals (Sweden)

Zhongfu Zhou

2017-12-01

Full Text Available This paper provides a review on various PV simulator technologies as well as presents a novel equivalent photovoltaic (PV source that was constructed by using un-illuminated solar panels and a DC power supply that operates in current source mode. The constructed PV source was used for testing photovoltaic converters and various maximum power point tracking (MPPT algorithms required for capturing the maximum possible output power. The mathematical model and electrical characteristics of the constructed PV source were defined and analyzed in detail in the paper. The constructed PV source has the advantages of high bandwidth over the switching circuit based PV simulators. The constructed PV source has been used for testing various power electronics converters and various control techniques effectively in laboratory environments for researchers and university students.

Proposed principles on the use of nuclear power sources in space

International Nuclear Information System (INIS)

Bennett, G.L.

1988-01-01

Since the 1978 reentry of the Soviet satellite Cosmos 954, the United Nations has been discussing the use of nuclear power sources in outer space. Most of these deliberations have taken place in the U.N. Committee on the Peaceful Uses of Outer Space, its two subcommittees (Scientific and Technical Subcommittee and Legal Subcommittee) and their associated working groups. This paper focuses on the technical agreements reached by the Working Group on the Use of Nuclear Power Sources in Outer Space (WGNPS), the legal principles agreed to by the Legal Subcommittee, and relevant treaties on the use of outer space and the use of nuclear power. To date the conclusion reached by the WGNPS in its 1981 report represents a succinct statement of U.N. consensus and of the U.S. position: The Working Group reaffirmed its previous conclusion that nuclear power sources can be used safely in outer space, provided that all necessary safety precautions are met

Detecting switching and intermittent causalities in time series

Science.gov (United States)

Zanin, Massimiliano; Papo, David

2017-04-01

During the last decade, complex network representations have emerged as a powerful instrument for describing the cross-talk between different brain regions both at rest and as subjects are carrying out cognitive tasks, in healthy brains and neurological pathologies. The transient nature of such cross-talk has nevertheless by and large been neglected, mainly due to the inherent limitations of some metrics, e.g., causality ones, which require a long time series in order to yield statistically significant results. Here, we present a methodology to account for intermittent causal coupling in neural activity, based on the identification of non-overlapping windows within the original time series in which the causality is strongest. The result is a less coarse-grained assessment of the time-varying properties of brain interactions, which can be used to create a high temporal resolution time-varying network. We apply the proposed methodology to the analysis of the brain activity of control subjects and alcoholic patients performing an image recognition task. Our results show that short-lived, intermittent, local-scale causality is better at discriminating both groups than global network metrics. These results highlight the importance of the transient nature of brain activity, at least under some pathological conditions.

High Power Modulator/regulators for neutral beam sources

International Nuclear Information System (INIS)

Lawson, J.Q.; Deitz, A.

1975-01-01

PPPL has recently completed two new Modulator/Regulators for neutral injection sources used on the ATC machine and is constructing four new ones for use with sources on the PLT machine. The ATC modulator uses the well proven 4CX35,000C tetrode as the main switch tube, while the PLT modulators will be using the new but significantly higher powered X-2170 tetrodes. Some interesting circuit and manufacturing techniques are discussed

Integrated Photovoltaic System Used as an Alternative Power Source

Directory of Open Access Journals (Sweden)

Ionel Laurentiu Alboteanu

2014-09-01

Full Text Available This paper presents a solution to use solar energy as an alternative source of electricity to conventional sources. The solution is to use a compact photovoltaic system integrated into a micro smart grid. The studied photovoltaic system is used into concrete application for the power supply lighting in a didactic laboratory.

Characterization of intermittency in zooplankton behaviour in turbulence.

Science.gov (United States)

Michalec, François-Gaël; Schmitt, François G; Souissi, Sami; Holzner, Markus

2015-10-01

We consider Lagrangian velocity differences of zooplankters swimming in still water and in turbulence. Using cumulants, we quantify the intermittency properties of their motion recorded using three-dimensional particle tracking velocimetry. Copepods swimming in still water display an intermittent behaviour characterized by a high probability of small velocity increments, and by stretched exponential tails. Low values arise from their steady cruising behaviour while heavy tails result from frequent relocation jumps. In turbulence, we show that at short time scales, the intermittency signature of active copepods clearly differs from that of the underlying flow, and reflects the frequent relocation jumps displayed by these small animals. Despite these differences, we show that copepods swimming in still and turbulent flow belong to the same intermittency class that can be modelled by a log-stable model with non-analytical cumulant generating function. Intermittency in swimming behaviour and relocation jumps may enable copepods to display oriented, collective motion under strong hydrodynamic conditions and thus, may contribute to the formation of zooplankton patches in energetic environments.

Operating modes and practical power flow analysis of bidirectional isolated power interface for distributed power systems

International Nuclear Information System (INIS)

Wen, Huiqing; Su, Bin

2016-01-01

Highlights: • Four operating modes of Dual-Phase-Shift control for Dual Active Bridge converter are presented. • Effects of “minor parameters” such as the deadtime and power device voltage drops are analyzed. • Accurate power flow models with Dual-Phase-Shift control are developed and verified with experimental results. • Optimal operating mode is determined with respect to the efficiency improvement. • Measured efficiency of the Dual Active Bridge converter is improved up to 14%. - Abstract: Due to the intermittent nature of the renewable energy sources including photovoltaic and wind energy, the energy storage systems are essential to stabilize dc bus voltage. Considering the discharge depth of super-capacitors and energy-storage batteries, the bidirectional isolated power interface will operate for a wide range of voltage and power. This study focuses on in-depth analysis of the dual-active-bridge dc–dc converter that is controlled by the dual-phase-shift scheme to improve the conversion efficiency in distributed power system. The power flow of each operating mode with dual-phase-shift control is characterized based on a detailed analysis of the effects of “minor parameters”, including the deadtime and power device voltage drops. The complete output power plane of the dual-active-bridge converter with dual-phase-shift control is obtained and compared with experimental results. The optimal operating mode is determined according to the practical output power range and the power flow characteristics. Experimental evaluation shows the effectiveness of the proposed power flow model with dual-phase-shift control and significant efficiency improvement using the optimal mode of dual-phase-shift compared with the conventional phase shift control.

Magnet power supplies for the Advanced Light Source

International Nuclear Information System (INIS)

Jackson, L.T.; Lutz, I.C.

1989-03-01

The Lawrence Berkeley Laboratory (LBL) is building an Advanced Light Source (ALS) to produce synchrotron radiation. An electron linear accelerator, and a booster synchrotron are used to accelerate the electron beam to 1.5 GeV to fill the storage ring. This paper describes the power supplies used for the magnets in the booster and the storage ring and the interface requirements for computer control and monitoring the power supplies and magnet currents. 1 ref., 3 figs., 2 tabs

ELBE Center for High-Power Radiation Sources

Directory of Open Access Journals (Sweden)

Peter Dr. Michel

2016-01-01

Full Text Available In the ELBE Center for High-Power Radiation Sources, the superconducting linear electron accelerator ELBE, serving  two free electron lasers, sources for intense coherent THz radiation, mono-energetic positrons, electrons, γ-rays, a neutron time-of-flight system as well as two synchronized ultra-short pulsed Petawatt laser systems are collocated. The characteristics of these beams make the ELBE center a unique research instrument for a variety of external users in fields ranging from material science over nuclear physics to cancer research, as well as scientists of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR.

Wind power's coming of age

International Nuclear Information System (INIS)

Phillips, J.A.

1992-01-01

This article examines the role that wind power has in meeting future energy demand. The topics of the article include demonstration of current technology, an overview of research and market activity, institutional and regulatory barriers and other issues, financing of wind power projects, incentives and penalties, current market experience, national trends in application of wind power plants, advanced technologies, intermittency, power quality, and transmission and distribution

Swiss pumped hydro storage potential for Germany's electricity system under high penetration of intermittent renewable energy

NARCIS (Netherlands)

van Meerwijk, Aagje J. H.; Benders, Reinerus; Davila-Martinez, Alejandro; Laugs, Gideon A. H.

2016-01-01

In order to cut greenhouse-gas emissions and increase energy security, the European Commission stimulates the deployment of intermittent renewable energy sources (IRES) towards 2050. In an electricity system with high shares of IRES implemented in the network, energy balancing like storage is needed

Target development for the SINQ high-power neutron spallation source

International Nuclear Information System (INIS)

Wagner, Werner

2002-01-01

SINQ is a 1 MW class research spallation neutron source, driven by the PSI proton accelerator system. In terms of beam power, it is, by a large margin, the most powerful spallation neutron source currently in operation worldwide. As a consequence, target load levels prevail in SINQ which are beyond the realm of existing experience. Therefore, an extensive materials irradiation program (STIP) is currently underway which will help to select the proper structural material and make dependable life time estimates accounting for the real operating conditions that prevail in the facility. In parallel, both theoretical and experimental work is going on within the MEGAPIE (MEGAwatt Pilot Experiment) project, to develop a liquid lead-bismuth spallation target for a beam power level of 1MW

Postexercise cold-water immersion improves intermittent high-intensity exercise performance in normothermia.

Science.gov (United States)

McCarthy, Avina; Mulligan, James; Egaña, Mikel

2016-11-01

A brief cold water immersion between 2 continuous high-intensity exercise bouts improves the performance of the latter compared with passive recovery in the heat. We investigated if this effect is apparent in normothermic conditions (∼19 °C), employing an intermittent high-intensity exercise designed to reflect the work performed at the high-intensity domain in team sports. Fifteen young active men completed 2 exhaustive cycling protocols (Ex1 and Ex2: 12 min at 85% ventilatory threshold (VT) and then an intermittent exercise alternating 30-s at 40% peak power (P peak ) and 30 s at 90% P peak to exhaustion) separated by 15 min of (i) passive rest, (ii) 5-min cold-water immersion at 8 °C, and (iii) 10-min cold-water immersion at 8 °C. Core temperature, heart rate, rates of perceived exertion, and oxygen uptake kinetics were not different during Ex1 among conditions. Time to failure during the intermittent exercise was significantly (P immersions (7.2 ± 3.5 min and 7.3 ± 3.3 min, respectively) compared with passive rest (5.8 ± 3.1 min). Core temperature, heart rate, and rates of perceived exertion were significantly (P immersions compared with passive rest. The time constant of phase II oxygen uptake response during the 85% VT bout of Ex2 was not different among the 3 conditions. A postexercise, 5- to 10-min cold-water immersion increases subsequent intermittent high-intensity exercise compared with passive rest in normothermia due, at least in part, to reductions in core temperature, circulatory strain, and effort perception.

Sustainability index approach as a selection criteria for energy storage system of an intermittent renewable energy source

International Nuclear Information System (INIS)

Raza, Syed Shabbar; Janajreh, Isam; Ghenai, Chaouki

2014-01-01

Highlights: • Three renewable energy storage options considered: lead acid and lithium polymer batteries and fuel cell. • Hydrogen fuel cell system is the most feasible energy storage option for the long term energy storage. • Sustainability index approach is a novel method used to quantify the qualitative properties of the system. - Abstract: The sustainability index is an adaptive, multicriteria and novel technique that is used to compare different energy storage systems for their sustainability. This innovative concept utilizes both qualitative and quantitative results to measure sustainability through an index based approach. This report aims to compare three different energy storage options for an intermittent renewable energy source. The three energy storage options are lead acid batteries, lithium polymer batteries and fuel cell systems, that are selected due to their availability and the geographical constrain of using other energy storage options. The renewable energy source used is solar photovoltaic (PV). Several technical, economic and environmental factors have been discussed elaborately which would help us to evaluate the merits of the energy storage system for long term storage. Finally, a novel sustainability index has been proposed which quantifies the qualitative and quantitative aspects of the factors discussed, and thus helps us choose the ideal energy storage system for our scenario. A weighted sum approach is used to quantify each factor according to their importance. After a detailed analysis of the three energy storage systems through the sustainability index approach, the most feasible energy storage option was found to be fuel cell systems which can provide a long term energy storage option and also environmental friendly

Power-Law Template for IR Point Source Clustering

Science.gov (United States)

Addison, Graeme E.; Dunkley, Joanna; Hajian, Amir; Viero, Marco; Bond, J. Richard; Das, Sudeep; Devlin, Mark; Halpern, Mark; Hincks, Adam; Hlozek, Renee;

Power-Law Template for Infrared Point-Source Clustering

Science.gov (United States)

Addison, Graeme E; Dunkley, Joanna; Hajian, Amir; Viero, Marco; Bond, J. Richard; Das, Sudeep; Devlin, Mark J.; Halpern, Mark; Hincks, Adam D; Hlozek, Renee;

The role of power sources in the European electricity mix

Directory of Open Access Journals (Sweden)

Bonin Bernard

2017-01-01

Full Text Available The ongoing debate in Europe about energy transition enhances the necessity to evaluate the performance of the envisaged mix of power sources, in terms of production cost, CO2 emissions and security of supply. In this study, we use MIXOPTIM, a Monte-Carlo simulator of the behavior of a mix of power sources on a territory, to evaluate the performance of the present EU power mix. After a validation on the French mix, we applied it to the whole EU territory and made variational calculations around the present mix to evaluate the performance impacts induced by small changes in installed renewable power and nuclear power. According to the analyzed criteria, the study shows that a plausible way to keep an affordable MWh in Europe with minimal amount of CO2 emissions and acceptable security of supply could be to extend the life of existing Gen II nuclear reactors. All other options lead to the degradation of the mix performance, on at least one of the three criteria listed above.

Urges use of renewable energy sources to generate electric power

International Nuclear Information System (INIS)

Santizo, Rodolfo

2001-01-01

The article discusses the following issues of generation of electric power through renewable energy sources like geothermal and wind energy. The author that is the actual Deputy Minister of Energy and Mines explains the needs of Guatemala in the sector of energy in promoting the renewable energy sources such as wind and geothermal energy because Guatemala has a potential generation by this sources

Design criteria for an uninterruptable power source (UPS)

Energy Technology Data Exchange (ETDEWEB)

Okeke, S.S.N. [Nnamdi Azikiwe Univ. Awka (Nigeria). Dept. of Science Technology; Okeke, C.A. [Nnamdi Azikiwe Univ. Awka (Nigeria). Dept. of Science Technology; Mortune, B.U. [Nnamdi Azikiwe Univ. Awka (Nigeria). Dept. of Science Technology; Okeke, C.C. [Univ. of Nigeria, Nsukka (Nigeria). Dept. of Computer Science

1997-05-01

This paper on uninterruptible power source (UPS) is a result of an R and D project; it describes the components of a UPS system and reviews the design requirements necessary for its construction with low cost and ease of maintenance. (orig.)

Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

Science.gov (United States)

Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

2016-01-01

Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells.

Designing and Testing Energy Harvesters Suitable for Renewable Power Sources

International Nuclear Information System (INIS)

Synkiewicz, B.; Guzdek, P.; Piekarski, J.; Zaraska, K.

2016-01-01

Energy harvesters convert waste power (heat, light and vibration) directly to electric power . Fast progress in their technology, design and areas of application (e.g. “Internet of Things”) has been observed recently. Their effectiveness is steadily growing which makes their application to powering sensor networks with wireless data transfer reasonable. The main advantage is the independence from wired power sources, which is especially important for monitoring state of environmental parameters. In this paper we describe the design and realization of a gas sensor monitoring CO level (powered by TEG) and two, designed an constructed in ITE, autonomous power supply modules powered by modern photovoltaic cells

Which factors make clean intermittent (self) catheterisation successful?

NARCIS (Netherlands)

Cobussen-Boekhorst, H.; Beekman, J.; Wijlick, E. van; Schaafstra, J.; Kuppevelt, D. van; Heesakkers, J.P.

2016-01-01

AIMS AND OBJECTIVES: To explore which factors determine successful intermittent catheterisation. BACKGROUND: Intermittent catheterisation is a safe, effective treatment and is associated with improved quality of life, although negative issues are reported. Factors which determine adherence are

Use a renewable energy sources and latest power-saving technologies in the the Republic Kazakstan

International Nuclear Information System (INIS)

Gulevich, N.V.

1996-01-01

The subject of alternative power in Kazakstan is brought up. Wind-, hydro-, solar power, biogas installation can improve the Republic power base. The main directions of activity of A. Einstein International Power engineering Academy on involving renewable energy sources and latest power-saving technologies to Republic of Kazakstan's fuel-power balance is given. It should be noted that renewable power engineering usually handles reversible energy sources and reserved power cycles. (author)

Effects of Intermittent Fasting, Caloric Restriction, and Ramadan Intermittent Fasting on Cognitive Performance at Rest and During Exercise in Adults.

Science.gov (United States)

Cherif, Anissa; Roelands, Bart; Meeusen, Romain; Chamari, Karim

2016-01-01

The aim of this review was to highlight the potent effects of intermittent fasting on the cognitive performance of athletes at rest and during exercise. Exercise interacts with dietary factors and has a positive effect on brain functioning. Furthermore, physical activity and exercise can favorably influence brain plasticity. Mounting evidence indicates that exercise, in combination with diet, affects the management of energy metabolism and synaptic plasticity by affecting molecular mechanisms through brain-derived neurotrophic factor, an essential neurotrophin that acts at the interface of metabolism and plasticity. The literature has also shown that certain aspects of physical performance and mental health, such as coping and decision-making strategies, can be negatively affected by daylight fasting. However, there are several types of intermittent fasting. These include caloric restriction, which is distinct from fasting and allows subjects to drink water ad libitum while consuming a very low-calorie food intake. Another type is Ramadan intermittent fasting, which is a religious practice of Islam, where healthy adult Muslims do not eat or drink during daylight hours for 1 month. Other religious practices in Islam (Sunna) also encourage Muslims to practice intermittent fasting outside the month of Ramadan. Several cross-sectional and longitudinal studies have shown that intermittent fasting has crucial effects on physical and intellectual performance by affecting various aspects of bodily physiology and biochemistry that could be important for athletic success. Moreover, recent findings revealed that immunological variables are also involved in cognitive functioning and that intermittent fasting might impact the relationship between cytokine expression in the brain and cognitive deficits, including memory deficits.

Four giga joule flywheel motor-generator for JT-60 toroidal field coil power supply system

International Nuclear Information System (INIS)

Matsukawa, T.; Kanke, M.; Shimada, R.; Yoshida, Y.; Yamashita, K.; Nakayama, T.

1986-01-01

A fusion test reactor often needs motor-generators as a power source in order to reduce disturbances to utility lines. The toroidal field coil power supply system of JT-60 also adopted a motor-generator for this purpose. The motor-generator started operation in April, 1985 at Japan Atomic Energy Research Institute together with the whole system. The motor-generator has several special features both electrically and mechanically. One electrical feature is that it is used as a pulse source of large current and power for periodic short-time duty. A mechanical feature is that a large flywheel is directly coupled to the motor-generator shaft and operated intermittently and at high speed. Therefore detailed investigations were carried out concerning constitution, characteristics as well as the coordination with the system performance. This paper describes the outlines of the flywheel motor-generator and discusses several topics

Photonic integrated circuits unveil crisis-induced intermittency.

Science.gov (United States)

Karsaklian Dal Bosco, Andreas; Akizawa, Yasuhiro; Kanno, Kazutaka; Uchida, Atsushi; Harayama, Takahisa; Yoshimura, Kazuyuki

2016-09-19

We experimentally investigate an intermittent route to chaos in a photonic integrated circuit consisting of a semiconductor laser with time-delayed optical feedback from a short external cavity. The transition from a period-doubling dynamics to a fully-developed chaos reveals a stage intermittently exhibiting these two dynamics. We unveil the bifurcation mechanism underlying this route to chaos by using the Lang-Kobayashi model and demonstrate that the process is based on a phenomenon of attractor expansion initiated by a particular distribution of the local Lyapunov exponents. We emphasize on the crucial importance of the distribution of the steady-state solutions introduced by the time-delayed feedback on the existence of this intermittent dynamics.

Chaos synchronization based on intermittent state observer

Institute of Scientific and Technical Information of China (English)

Li Guo-Hui; Zhou Shi-Ping; Xu De-Ming

2004-01-01

This paper describes the method of synchronizing slave to the master trajectory using an intermittent state observer by constructing a synchronizer which drives the response system globally tracing the driving system asymptotically. It has been shown from the theory of synchronization error-analysis that a satisfactory result of chaos synchronization is expected under an appropriate intermittent period and state observer. Compared with continuous control method,the proposed intermittent method can target the desired orbit more efficiently. The application of the method is demonstrated on the hyperchaotic Rossler systems. Numerical simulations show that the length of the synchronization interval rs is of crucial importance for our scheme, and the method is robust with respect to parameter mismatch.

Intermittent vs. Continuous Anticoagulation theRapy in patiEnts with Atrial Fibrillation (iCARE-AF): a randomized pilot study.

Science.gov (United States)

Stavrakis, Stavros; Stoner, Julie A; Kardokus, Joel; Garabelli, Paul J; Po, Sunny S; Lazzara, Ralph

2017-01-01

We hypothesized that intermittent anticoagulation based on daily rhythm monitoring using the novel oral anticoagulants (NOACs) is feasible and safe among patients with paroxysmal atrial fibrillation (AF). Patients with paroxysmal AF and ≥1 risk factors for stroke were randomized to either intermittent or continuous anticoagulation. Those in the intermittent group were instructed to transmit a daily ECG using an iPhone-based rhythm monitoring device. If AF was detected, patients received one of the NOACs for 48 h-1 week. Patients who failed to transmit an ECG for three consecutive days or more than 7 days total were crossed over to continuous anticoagulation. Patients in the continuous group received one of the NOACs. Fifty-eight patients were randomized to either intermittent (n = 29) or continuous anticoagulation (n = 29). Over a median follow-up of 20 months, 20 patients in the intermittent group failed to submit a daily ECG at least once (median three failed submissions). Four patients (14 %) crossed over to continuous anticoagulation due to failure to submit an ECG for three consecutive days. One stroke (continuous group) occurred during the study. Major bleeding occurred in two patients in the continuous and one patient in the intermittent group, after crossing over to continuous anticoagulation. In a prespecified per-protocol analysis, gastrointestinal bleeding was more frequent in the continuous group (16 vs. 0 %; p = 0.047). Intermittent anticoagulation based on daily rhythm monitoring is feasible and may decrease bleeding in low-risk patients with paroxysmal AF. A larger trial, adequately powered to detect clinical outcomes, is warranted.

Controls on streamflow intermittence in the Colorado Front Range

Science.gov (United States)

Kampf, S. K.; Puntenney, K.; Martin, C.; Weber, R.; Gerlich, J.; Hammond, J. C.; Lefsky, M. A.

2017-12-01

Intermittent streams comprise more than 60% of the channel length in semiarid northern Colorado, yet little is known about their flow magnitude and timing. We used field surveys, stream sensors, and remote sensing to quantify spatial and temporal patterns of streamflow intermittence in the Cache la Poudre basin in 2016-2017. To evaluate potential controls on streamflow intermittence, we delineated the drainage area to each monitored point and quantified the catchment's mean precipitation, temperature, snow persistence, slope, aspect, vegetation type, soil type, and bedrock geology. During the period of study, most streams below 2500 m elevation and drainage areas >1 km2 had perennial flow, whereas nearly all streams with drainage areas <1 km2 had intermittent flow. For the high elevation intermittent streams, stream locations often differed substantially from the locations mapped in standard GIS data products. Initial analyses have identified no clearly quantifiable controls on flow duration of high elevation streams, but field observations indicate subsurface flow paths are important contributors to surface streams.

Methods of formation of efficiency indexes of electric power sources integration in regional electric power systems

International Nuclear Information System (INIS)

Marder, L.I.; Myzin, A.I.

1993-01-01

A methodic approach to the grounding of the integration process efficiency within the Unified electric power system is given together with the selection of a rational areal structure and concentration of power-generating source capacities. Formation of an economic functional according to alternative scenavies including the cost components taking account of the regional interests is considered. A method for estimation and distribution of the effect from electric power production integration in the power systems under new economic conditions is proposed

High stability power sources for bending and quadrupole magnets of TRISTAN project

International Nuclear Information System (INIS)

Kumagai, Noritaka; Ogawa, Shin-ichi; Koseki, Shoichiro; Nagasaka, Saburo.

1985-01-01

The excitation power sources for the main ring magnets of the TRISTAN project of the Ministry of Educations's National Laboratory for High Energy Physics requires strict performances of 10 -4 for both long time stability and the ripple factor of the DC output current to obtain a stable beam. To satisfy such specifications, a precision current detector, and active filter, and other such technologies are used for the power source. To verify the performance of this power source, a prototype was manufactured and a combined test was done with the magnets actually used at the National Laboratory. The results have proved that the output stability, ripple factor, current tracking, and other specifications are quite satisfactory and, at present, 80 sets have been manufactured for the TRISTAN project. This paper describes the project's power supply system and reports the results of performance tests on the prototype. (author)

Clinical study of intermittent lock of the temporomandibular joint. Relation to frequency of intermittent lock on clinical examination and magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Ide, Takashi; Nagai, Itaru; Miyazaki, Akihiro; Yamaguchi, Akira; Kohama, Geniku [Sapporo Medical Univ. (Japan). School of Medicine

2002-03-01

To examine the occurrence of intermittent lock, we investigated the correlation between the frequency of intermittent lock of the temporomandibular joint and magnetic resonance imaging (MRI) findings. The subjects consisted of 25 patients (25 joints) with unilateral intermittent lock who were treated from April 1994 through March 2000 at our department. MRI examination of the joint was performed on the affected side. We divided the patients into two groups: a high-frequency group consisting of 15 patients who had symptoms of intermittent lock every day and a low-frequency group consisting of 10 patients who did not have symptoms every day. The results showed no statistical difference between the two groups in clinical findings such as age, sex, clicking side of the joint, duration of intermittent lock, method of unlocking, muscle pain on palpation, degree of maximal mouth opening, distance between the maxillary and mandibular tooth midline, or the degree of overbite and overjet. However, the two groups differed significantly in the degree of anterior disc displacement as assessed by MRI. (author)

Comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters

Energy Technology Data Exchange (ETDEWEB)

Pettersson, S.

2009-07-01

During the past two decades, active power filters have increasingly grown their popularity as a viable method for improving electric power quality. The main reasons for this have been the advent of fast self-commutating solid-state devices, the progression of digital technology and the improved sensor technology. Four-wire active power filters provide an efficient solution for improving the quality of supply in grounded three-phase systems or three-phase systems with neutral conductors, which are commonly used for powering residential, office and public buildings. Four-wire active power filters are applicable in compensating current harmonics, reactive power, neutral current and load phase imbalance.This thesis presents a comparative study of microcontroller controlled four-wire voltage and current source shunt active power filters. The study includes two voltage source topologies and a current source topology with two different dc-link energy storage structures, which are compared on the basis of their filtering properties, filtering performance and efficiency. The obtained results are used for determining the suitability of current source technology for four-wire active power filtering and finding the most viable four-wire shunt active power filter topology. One commonly recognized disadvantage of the current source active power filter has always been the bulky dc-link inductor. To reduce the size of the dc-link inductor, an alternative dc-link structure for current source active power filters was introduced in the late 80's. The hybrid energy storage consists of both inductive and capacitive energy storage elements, two diodes and two controllable semiconductor switching devices. Since the capacitive element is used as a main storage unit, the inductance of the dc-link inductor can be considerably reduced. However, the original dc current control method proposed is not able to utilize the full potential of the hybrid energy storage and the inductance

Teacher Views on School Administrators' Organizational Power Sources and Their Change Management Behaviours

Science.gov (United States)

Argon, Türkan; Dilekçi, Ümit

2016-01-01

This study aimed to determine school administrators' organizational power sources and change management behaviours based on Bolu central district primary and secondary school teachers' views. The study conducted with relational screening model reached 286 teachers. School Administrators' Organizational Power Sources Scale and Change Management…

Voltage regulated hybrid DC power source using supercapacitors as energy storage device

International Nuclear Information System (INIS)

Ayad, Mohamed-Yacine; Pierfederici, Serge; Rael, Stephane; Davat, Bernard

2007-01-01

The management of embedded electrical energy needs a storage system with high dynamic performances in order to shave transient power peaks and to compensate for the intrinsic limitations of the main source. The use of supercapacitors for this storage system is quite suitable because of appropriate electrical characteristics (huge capacitance, weak series resistance, high specific energy, high specific power), direct storage (energy ready for use) and easy control by power electronic conversion. This paper deals with the conception and realisation of a voltage regulated hybrid DC power source using supercapacitors as an auxiliary storage device. Here, we present the structure, control principle and results associated with experimental validation. Our interest will be focused on the management of transient power peaks

Voltage regulated hybrid DC power source using supercapacitors as energy storage device

Energy Technology Data Exchange (ETDEWEB)

Ayad, Mohamed-Yacine; Pierfederici, Serge; Rael, Stephane; Davat, Bernard [Groupe de Recherche en Electrotechnique et Electronique de Nancy, Centre National de la Recherche Scientifique (Unite Mixte de Recherche 7037), 2, Avenue de la Foret de Haye, 54516 Vandoeuvre-les-Nancy (France)

2007-07-15

The management of embedded electrical energy needs a storage system with high dynamic performances in order to shave transient power peaks and to compensate for the intrinsic limitations of the main source. The use of supercapacitors for this storage system is quite suitable because of appropriate electrical characteristics (huge capacitance, weak series resistance, high specific energy, high specific power), direct storage (energy ready for use) and easy control by power electronic conversion. This paper deals with the conception and realisation of a voltage regulated hybrid DC power source using supercapacitors as an auxiliary storage device. Here, we present the structure, control principle and results associated with experimental validation. Our interest will be focused on the management of transient power peaks. (author)

Power-law thermal model for blackbody sources

International Nuclear Information System (INIS)

Del Grande, N.K.

1979-01-01

The spectral radiant emittance W/sub E/ from a blackbody at a temperature kT for photons at energies E above the spectral peak (2.82144 kT) varies as (kT)/sup E/kT/. This power-law temperature dependence, an approximation of Planck's radiation law, may have applications for measuring the emissivity of sources emitting in the soft x-ray region

Intermittent versus continuous exercise training in chronic heart failure: a meta-analysis.

Science.gov (United States)

Smart, Neil A; Dieberg, Gudrun; Giallauria, Francesco

2013-06-20

We conducted a meta-analysis of randomized, controlled trials of combined strength and intermittent aerobic training, intermittent aerobic training only and continuous exercise training in heart failure patients. A systematic search was conducted of Medline (Ovid) (1950-September 2011), Embase.com (1974-September 2011), Cochrane Central Register of Controlled Trials and CINAHL (1981-September 19 2011). The search strategy included a mix of MeSH and free text terms for the key concepts heart failure, exercise training, interval training and intermittent exercise training. The included studies contained an aggregate of 446 patients, 212 completed intermittent exercise training, 66 only continuous exercise training, 59 completed combined intermittent and strength training and 109 sedentary controls. Weighted mean difference (MD) in Peak VO2 was 1.04mlkg(-1)min(-1) and (95% C.I.) was 0.42-1.66 (p=0.0009) in intermittent versus continuous exercise training respectively. Weighted mean difference in Peak VO2 was -1.10mlkg(-1)min(-1) (95% C.I.) was -1.83-0.37 p=0.003 for intermittent only versus intermittent and strength (combined) training respectively. In studies reporting VE/VCO2 for intermittent versus control groups, MD was -1.50 [(95% C.I. -2.64, -0.37), p=0.01] and for intermittent versus continuous exercise training MD was -1.35 [(95% C.I. -2.15, -0.55), p=0.001]. Change in peak VO2 was positively correlated with weekly exercise energy expenditure for intermittent exercise groups (r=0.48, p=0.05). Combined strength and intermittent exercise appears superior for peak VO2 changes when compared to intermittent exercise of similar exercise energy expenditure. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Status of R&D activity for ITER ICRF power source system

International Nuclear Information System (INIS)

Mukherjee, Aparajita; Trivedi, Rajesh; Singh, Raghuraj; Rajnish, Kumar; Machchhar, Harsha; Ajesh, P.; Suthar, Gajendra; Soni, Dipal; Patel, Manoj; Mohan, Kartik; Hari, J.V.S.; Anand, Rohit; Verma, Sriprakash; Agarwal, Rohit; Jha, Akhil; Kazarian, Fabienne; Beaumont, Bertrand

2015-01-01

Highlights: • R&D program to establish high power RF technology for ITER ICRF source is described. • R&D RF source is being developed using Diacrode & Tetrode technologies. • Test rig (3 MW/3600 s/35–65 MHz) simulating plasma load is developed. - Abstract: India is in-charge for the procurement of ITER Ion Cyclotron Resonance Frequency (ICRF) sources (1 Prototype + 8 series units) along with auxiliary power supplies and Local Control Unit. As there is no unique amplifier chain able to meet the output power specifications as per ITER requirement (2.5 MW per source at 35–65 MHz/CW/VSWR 2.0), two parallel three-stage amplifier chains along with a combiner circuit on the output side is considered. This kind of RF source will be unique in terms of its stringent specifications and building a first of its kind is always a challenge. An R&D phase has been initiated for establishing the technology considering single amplifier chain experimentation (1.5 MW/35–65 MHz/3600 s/VSWR 2.0) prior to Prototype and series production. This paper presents the status of R&D activity to resolve technological challenges involved and various infrastructures developed at ITER-India lab to support such operation.

Status of R&D activity for ITER ICRF power source system

Energy Technology Data Exchange (ETDEWEB)

Mukherjee, Aparajita, E-mail: aparajita.mukherjee@iter-india.org [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar–382428 (India); Trivedi, Rajesh; Singh, Raghuraj; Rajnish, Kumar; Machchhar, Harsha; Ajesh, P.; Suthar, Gajendra; Soni, Dipal; Patel, Manoj; Mohan, Kartik; Hari, J.V.S.; Anand, Rohit; Verma, Sriprakash; Agarwal, Rohit; Jha, Akhil [ITER-India, Institute for Plasma Research, Bhat, Gandhinagar–382428 (India); Kazarian, Fabienne; Beaumont, Bertrand [ITER Organization, CS 90 046, 13067 Sain-Paul-Les-Durance (France)

2015-10-15

Highlights: • R&D program to establish high power RF technology for ITER ICRF source is described. • R&D RF source is being developed using Diacrode & Tetrode technologies. • Test rig (3 MW/3600 s/35–65 MHz) simulating plasma load is developed. - Abstract: India is in-charge for the procurement of ITER Ion Cyclotron Resonance Frequency (ICRF) sources (1 Prototype + 8 series units) along with auxiliary power supplies and Local Control Unit. As there is no unique amplifier chain able to meet the output power specifications as per ITER requirement (2.5 MW per source at 35–65 MHz/CW/VSWR 2.0), two parallel three-stage amplifier chains along with a combiner circuit on the output side is considered. This kind of RF source will be unique in terms of its stringent specifications and building a first of its kind is always a challenge. An R&D phase has been initiated for establishing the technology considering single amplifier chain experimentation (1.5 MW/35–65 MHz/3600 s/VSWR 2.0) prior to Prototype and series production. This paper presents the status of R&D activity to resolve technological challenges involved and various infrastructures developed at ITER-India lab to support such operation.

An electric-eel-inspired soft power source from stacked hydrogels

Science.gov (United States)

Schroeder, Thomas B. H.; Guha, Anirvan; Lamoureux, Aaron; Vanrenterghem, Gloria; Sept, David; Shtein, Max; Yang, Jerry; Mayer, Michael

2017-12-01

Progress towards the integration of technology into living organisms requires electrical power sources that are biocompatible, mechanically flexible, and able to harness the chemical energy available inside biological systems. Conventional batteries were not designed with these criteria in mind. The electric organ of the knifefish Electrophorus electricus (commonly known as the electric eel) is, however, an example of an electrical power source that operates within biological constraints while featuring power characteristics that include peak potential differences of 600 volts and currents of 1 ampere. Here we introduce an electric-eel-inspired power concept that uses gradients of ions between miniature polyacrylamide hydrogel compartments bounded by a repeating sequence of cation- and anion-selective hydrogel membranes. The system uses a scalable stacking or folding geometry that generates 110 volts at open circuit or 27 milliwatts per square metre per gel cell upon simultaneous, self-registered mechanical contact activation of thousands of gel compartments in series while circumventing power dissipation before contact. Unlike typical batteries, these systems are soft, flexible, transparent, and potentially biocompatible. These characteristics suggest that artificial electric organs could be used to power next-generation implant materials such as pacemakers, implantable sensors, or prosthetic devices in hybrids of living and non-living systems.

An electric-eel-inspired soft power source from stacked hydrogels.

Science.gov (United States)

Schroeder, Thomas B H; Guha, Anirvan; Lamoureux, Aaron; VanRenterghem, Gloria; Sept, David; Shtein, Max; Yang, Jerry; Mayer, Michael

2017-12-13

Progress towards the integration of technology into living organisms requires electrical power sources that are biocompatible, mechanically flexible, and able to harness the chemical energy available inside biological systems. Conventional batteries were not designed with these criteria in mind. The electric organ of the knifefish Electrophorus electricus (commonly known as the electric eel) is, however, an example of an electrical power source that operates within biological constraints while featuring power characteristics that include peak potential differences of 600 volts and currents of 1 ampere. Here we introduce an electric-eel-inspired power concept that uses gradients of ions between miniature polyacrylamide hydrogel compartments bounded by a repeating sequence of cation- and anion-selective hydrogel membranes. The system uses a scalable stacking or folding geometry that generates 110 volts at open circuit or 27 milliwatts per square metre per gel cell upon simultaneous, self-registered mechanical contact activation of thousands of gel compartments in series while circumventing power dissipation before contact. Unlike typical batteries, these systems are soft, flexible, transparent, and potentially biocompatible. These characteristics suggest that artificial electric organs could be used to power next-generation implant materials such as pacemakers, implantable sensors, or prosthetic devices in hybrids of living and non-living systems.

Microbial ecology of Campylobacter jejuni in a United Kingdom chicken supply chain: intermittent common source, vertical transmission, and amplification by flock propagation.

Science.gov (United States)

Pearson, A D; Greenwood, M H; Feltham, R K; Healing, T D; Donaldson, J; Jones, D M; Colwell, R R

1996-12-01

A study of Campylobacter jejuni on a broiler chicken farm between 1989 and 1994 gave an estimated isolation rate of 27% (3,304 of 12,233) from a 0.9% sample of 1.44 million broiler chickens from six to eight sheds over 32 consecutive rearing flocks comprising 251 broiler shed flocks. During the study, C. jejuni was found in 35.5% of the 251 shed flocks but only 9.2% (23 of 251) had Campylobacter isolates in successive flocks, with 9 of those 23 sheds having the same serotype between consecutive flocks, indicating a low level of transmission between flocks. Analysis of a systematic sample of 484 of 3,304 (14.6%) C. jejuni isolates showed that 85% were of 10 serotype complexes but 58% were of 3 serotype complexes, indicating a high degree of strain similarity throughout the entire study. The three commonest types were detected in 8 of 32 flocks during the 5-year study period, suggesting an intermittent common external Campylobacter source. This hypothesis was tested by a retrospective cohort analysis of C. jejuni rates and types by reference to hatchery supplier of the 1-day-old chicks. Isolation rates of C. jejuni and frequency distribution of types were determined in 6-week-old broiler chickens identified by the hatchery supplying the original chicks. The isolation rate of C. jejuni in broilers, supplied by hatchery A, was 17.6%, compared to 42.9% (P hatchery B. In two instances, when both hatcheries were used to stock the same farm flock, Campylobacter isolates were found only in those sheds with chicks supplied by hatchery B. Thus, the frequency distribution of Campylobacter types for chickens supplied by the two hatcheries over the 5-year period showed marked dissimilarity. These findings suggest that the isolation rate and type of Campylobacter isolates in broiler chickens was associated with the hatchery supplying chicks. The lack of diversity of types and the intermittent high positivity of sheds is evidence for a common source of C. jejuni introduced by

Polyolephine waste recycling as source of power energy

Directory of Open Access Journals (Sweden)

Tisovski Štefan

2008-01-01

Full Text Available Polyolephine waste (polyetilene, polypropilene is the main source of environmental pollution. Depolymerization of waste in reactor under atmospheric pressure yields hydrocarbon mixture C1-C34. In turn, combustion of C1-C7 fraction provides reactor temperature regime. The plant is automated and energetically highly efficient. Small electric power is required for operating the plant. The waste originating from depolymerazation does not pollute the environment. Fraction C7-C34 not only serves for commercial purposes but also as a power energy provider within the waste deploymerization plant.

An FEL power source for a TeV linear collider

International Nuclear Information System (INIS)

Hopkins, D.B.; Hoyer, E.H.; Halbach, K.

1988-10-01

In this paper we consider the design of a power source of a linear collider. We take a conservative approach and hence extrapolate as little as possible from present experience. Thus we establish a ''straw man''; i.e., a design which serves as an ''existence proof'' of a power source for a TeV collider. We take as the parameters to which the power source is designed those presented earlier by R. Palmer; namely: f = 17 GHz, W = 634 MW/m, L = 1.44m, W/sub T/ = 3.87 TW, R = 180 Hz, L/sub c/ = 7.41 km, T/sub p/ = 50 ns, where the quantity f is the desired frequency, W is the power needed per meter (for a gradient of 186 MeV/m), L is the length between feeds, W/sub T/ is the total power required, R is the rep-rate, L/sub c/ is the total length of the collider, and T/sub p/ is the rf pulse width. With no emittance dilution, this collider would produce a luminosity of 7.7 /times/ 10 32 cm/sup /minus/2/ sec/sup /minus/1/ for single bunch operation or 1.6 /times/ 10 34 cm/sup /minus/2/ sec/sup /minus/1/ for multi-bunch operating (i.e., 21 bunches). With realistic dilution and R = 386 Hz these luminosity values would be 5.0 /times/ 10 32 and 1.0 /times/ 10 34 cm/sup /minus/2/ sec/sup /minus/1/, respectively. 5 refs., 14 figs., 4 tabs

Various technical and legal aspects of nuclear power sources in outer space

International Nuclear Information System (INIS)

Boeck, H.; Summerer, L.

2001-12-01

Since the very first days of space exploration, nuclear power was considered as an alternative to solar cells for the generation of energy in space. Especially for larger exploration missions beyond Mars, nuclear power sources (NPS) are almost unavoidable. NPS are developed, produced and flown on a continuous basis since almost 40 years by the USA and the Soviet Union, now Russia. While the technological capabilities certainly exist within Europe, Europe has not developed space nuclear power sources. This work is structured in four parts, enlightening this subject from different viewpoints on the European level. In a first chapter, European centres researching in the broader field of this technology are listed. A second chapter deals with the properties and hazards connected with plutonium, the element used in Radioisotope Thermal Generators (RTG). Recent technological developments in the field of RTG are reviewed in chapter 4, while chapter 3 deals with the international legal implications of the use of nuclear power sources in outer space. Refs. 30 (author)

Effects of hydrogen rich water on prolonged intermittent exercise.

Science.gov (United States)

Da Ponte, Alessandro; Giovanelli, Nicola; Nigris, Daniele; Lazzer, Stefano

2018-05-01

Recent studies showed a positive effect of hydrogen rich water (HRW) intake on acid-base homeostasis at rest. We investigated 2-weeks of HRW intake on repeated sprint performance and acid-base status during prolonged intermittent cycling exercise. In a cross over single-blind protocol, 8 trained male cyclists (age [mean±SD] 41±7 years, body mass 72.3±4.4 kg, height 1.77±0.04 m, maximal oxygen uptake [V̇O2max] 52.6±4.4 mL·kg-1·min-1) were provided daily with 2 liters of placebo normal water (PLA, pH 7.6, oxidation/reduction potential [ORP] +230 mV, free hydrogen content 0 ppb) or HRW (pH 9.8, ORP -180 mV, free Hydrogen 450 ppb). Tests were performed at baseline and after each period of 2 weeks of treatment. The treatments were counter-balanced and the sequence randomized. The 30-minute intermittent cycling trial consisted in 10 3-minute blocks, each one composed by 90 seconds at 40% V̇O2max, 60 seconds at 60% V̇O2max, 16 seconds all out sprint, and 14 seconds active recovery. Oxygen uptake (V̇O2), heart rate and power output were measured during the whole test, while mean and peak power output (PPO), time to peak power and Fatigue Index (FI) were determined during all the 16 seconds sprints. Lactate, pH and bicarbonate (HCO3-) concentrations were determined at rest and after each sprint on blood obtained by an antecubital vein indwelling catheter. In the PLA group, PPO in absolute values decreased significantly at the 8th and 9th of 10 sprints and in relative values, ΔPPO, decreased significantly at 6th, 8th and 9th of 10 sprints (by mean: -12±5%, Pmay help to maintain PPO in repetitive sprints to exhaustion over 30 minutes.

The Jefferson Lab High Power Light Source

Energy Technology Data Exchange (ETDEWEB)

James R. Boyce

2006-01-01

Jefferson Lab has designed, built and operated two high average power free-electron lasers (FEL) using superconducting RF (SRF) technology and energy recovery techniques. Between 1999-2001 Jefferson Lab operated the IR Demo FEL. This device produced over 2 kW in the mid-infrared, in addition to producing world record average powers in the visible (50 W), ultraviolet (10 W) and terahertz range (50 W) for tunable, short-pulse (< ps) light. This FEL was the first high power demonstration of an accelerator configuration that is being exploited for a number of new accelerator-driven light source facilities that are currently under design or construction. The driver accelerator for the IR Demo FEL uses an Energy Recovered Linac (ERL) configuration that improves the energy efficiency and lowers both the capital and operating cost of such devices by recovering most of the power in the spent electron beam after optical power is extracted from the beam. The IR Demo FEL was de-commissioned in late 2001 for an upgraded FEL for extending the IR power to over 10 kW and the ultraviolet power to over 1 kW. The FEL Upgrade achieved 10 kW of average power in the mid-IR (6 microns) in July of 2004, and its IR operation currently is being extended down to 1 micron. In addition, we have demonstrated the capability of on/off cycling and recovering over a megawatt of electron beam power without diminishing machine performance. A complementary UV FEL will come on-line within the next year. This paper presents a summary of the FEL characteristics, user community accomplishments with the IR Demo, and planned user experiments.

Wave power as a source of energy along the Indian coast

Digital Repository Service at National Institute of Oceanography (India)

Das, V.K.

stream_size 16 stream_content_type text/plain stream_name Power_Directory_1992_141.pdf.txt stream_source_info Power_Directory_1992_141.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

Integration of permanent magnet synchronous generator wind turbines into power grid

Science.gov (United States)

Abedini, Asghar

The world is seeing an ever-increasing demand for electrical energy. The future growth of electrical power generation needs to be a mix of technologies including fossil fuels, hydro, nuclear, wind, and solar. The federal and state energy agencies have taken several proactive steps to increase the share of renewable energy in the total generated electrical power. In 2005, 11.1% of the total 1060 GW electricity generation capacity was from Renewable Energy Sources (RES) in the US. The power capacity portfolio included 9.2% from hydroelectric, 0.87% from wind, and 0.7% from biomass. Other renewable power capacity included 2.8 GW of geothermal, 0.4 GW of solar thermal, and 0.2 GW of solar PV. Although the share of renewable energy sources is small compared with the total power capacity, they are experiencing a high and steady growth. The US is leading the world in wind energy growth with a 27% increase in 2006 and a projected 26% increase in 2007, according to the American Wind Energy Association (AWEA). The US Department of Energy benchmarked a goal to meet 5% of the nation's energy need by launching the Wind Powering America (WPA) program. Although renewable energy sources have many benefits, their utilization in the electrical grid does not come without cost. The higher penetration of RES has introduced many technical and non-technical challenges, including power quality, reliability, safety and protection, load management, grid interconnections and control, new regulations, and grid operation economics. RES such as wind and PV are also intermittent in nature. The energy from these sources is available as long as there is wind or sunlight. However, these are energies that are abundant in the world and the power generated from these sources is pollution free. Due to high price of foundation of wind farms, employing variable speed wind turbines to maximize the extracted energy from blowing wind is more beneficial. On the other hand, since wind power is intermittent

Observation of intermittency in gene expression on cDNA microarrays

CERN Document Server

Peterson, L E

2002-01-01

We used scaled factorial moments to search for intermittency in the log expression ratios (LERs) for thousands of genes spotted on cDNA microarrays (gene chips). Results indicate varying levels of intermittency in gene expression. The observation of intermittency in the data analyzed provides a complimentary handle on moderately expressed genes, generally not tackled by conventional techniques.

Study and Analysis of an Intelligent Microgrid Energy Management Solution with Distributed Energy Sources

Directory of Open Access Journals (Sweden)

Swaminathan Ganesan

2017-09-01

Full Text Available In this paper, a robust energy management solution which will facilitate the optimum and economic control of energy flows throughout a microgrid network is proposed. The increased penetration of renewable energy sources is highly intermittent in nature; the proposed solution demonstrates highly efficient energy management. This study enables precise management of power flows by forecasting of renewable energy generation, estimating the availability of energy at storage batteries, and invoking the appropriate mode of operation, based on the load demand to achieve efficient and economic operation. The predefined mode of operation is derived out of an expert rule set and schedules the load and distributed energy sources along with utility grid.

InP MMIC Chip Set for Power Sources Covering 80-170 GHz

Science.gov (United States)

Ngo, Catherine

2001-01-01

We will present a Monolithic Millimeter-wave Integrated Circuit (MMIC) chip set which provides high output-power sources for driving diode frequency multipliers into the terahertz range. The chip set was fabricated at HRL Laboratories using a 0.1-micrometer gate-length InAlAs/InGaAs/InP high electron mobility transistor (HEMT) process, and features transistors with an f(sub max) above 600 GHz. The HRL InP HEMT process has already demonstrated amplifiers in the 60-200 GHz range. In this paper, these high frequency HEMTs form the basis for power sources up to 170 GHz. A number of state-of-the-art InP HEMT MMICs will be presented. These include voltage-controlled and fixed-tuned oscillators, power amplifiers, and an active doubler. We will first discuss an 80 GHz voltage-controlled oscillator with 5 GHz of tunability and at least 17 mW of output power, as well as a 120 GHz oscillator providing 7 mW of output power. In addition, we will present results of a power amplifier which covers the full WRIO waveguide band (75-110 GHz), and provides 40-50 mW of output power. Furthermore, we will present an active doubler at 164 GHz providing 8% bandwidth, 3 mW of output power, and an unprecedented 2 dB of conversion loss for an InP HEMT MMIC at this frequency. Finally, we will demonstrate a power amplifier to cover 140-170 GHz with 15-25 mW of output power and 8 dB gain. These components can form a power source in the 155-165 GHz range by cascading the 80 GHz oscillator, W-band power amplifier, 164 GHz active doubler and final 140-170 GHz power amplifier for a stable, compact local oscillator subsystem, which could be used for atmospheric science or astrophysics radiometers.

Ultracompact/ultralow power electron cyclotron resonance ion source for multipurpose applications

International Nuclear Information System (INIS)

Sortais, P.; Lamy, T.; Medard, J.; Angot, J.; Latrasse, L.; Thuillier, T.

2010-01-01

In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm 2 (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 μA extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 π mm mrad at 15 kV (1σ) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon beams

Ultracompact/ultralow power electron cyclotron resonance ion source for multipurpose applications

Energy Technology Data Exchange (ETDEWEB)

Sortais, P.; Lamy, T.; Medard, J.; Angot, J.; Latrasse, L.; Thuillier, T. [Laboratoire de Physique Subatomique et de Cosmologie de Grenoble, UJF-CNRS/IN2P3 - INPG, 53, rue des Martyrs, 38026 Grenoble Cedex (France)

2010-02-15

In order to drastically reduce the power consumption of a microwave ion source, we have studied some specific discharge cavity geometries in order to reduce the operating point below 1 W of microwave power (at 2.45 GHz). We show that it is possible to drive an electron cyclotron resonance ion source with a transmitter technology similar to those used for cellular phones. By the reduction in the size and of the required microwave power, we have developed a new type of ultralow cost ion sources. This microwave discharge system (called COMIC, for COmpact MIcrowave and Coaxial) can be used as a source of light, plasma or ions. We will show geometries of conductive cavities where it is possible, in a 20 mm diameter chamber, to reduce the ignition of the plasma below 100 mW and define typical operating points around 5 W. Inside a simple vacuum chamber it is easy to place the source and its extraction system anywhere and fully under vacuum. In that case, current densities from 0.1 to 10 mA/cm{sup 2} (Ar, extraction 4 mm, 1 mAe, 20 kV) have been observed. Preliminary measurements and calculations show the possibility, with a two electrodes system, to extract beams within a low emittance. The first application for these ion sources is the ion injection for charge breeding, surface analyzing system and surface treatment. For this purpose, a very small extraction hole is used (typically 3/10 mm for a 3 {mu}A extracted current with 2 W of HF power). Mass spectrum and emittance measurements will be presented. In these conditions, values down to 1 {pi} mm mrad at 15 kV (1{sigma}) are observed, thus very close to the ones currently observed for a surface ionization source. A major interest of this approach is the possibility to connect together several COMIC devices. We will introduce some new on-going developments such as sources for high voltage implantation platforms, fully quartz radioactive ion source at ISOLDE or large plasma generators for plasma immersion, broad or ribbon

Small-world networks exhibit pronounced intermittent synchronization

Science.gov (United States)

Choudhary, Anshul; Mitra, Chiranjit; Kohar, Vivek; Sinha, Sudeshna; Kurths, Jürgen

2017-11-01

We report the phenomenon of temporally intermittently synchronized and desynchronized dynamics in Watts-Strogatz networks of chaotic Rössler oscillators. We consider topologies for which the master stability function (MSF) predicts stable synchronized behaviour, as the rewiring probability (p) is tuned from 0 to 1. MSF essentially utilizes the largest non-zero Lyapunov exponent transversal to the synchronization manifold in making stability considerations, thereby ignoring the other Lyapunov exponents. However, for an N-node networked dynamical system, we observe that the difference in its Lyapunov spectra (corresponding to the N - 1 directions transversal to the synchronization manifold) is crucial and serves as an indicator of the presence of intermittently synchronized behaviour. In addition to the linear stability-based (MSF) analysis, we further provide global stability estimate in terms of the fraction of state-space volume shared by the intermittently synchronized state, as p is varied from 0 to 1. This fraction becomes appreciably large in the small-world regime, which is surprising, since this limit has been otherwise considered optimal for synchronized dynamics. Finally, we characterize the nature of the observed intermittency and its dominance in state-space as network rewiring probability (p) is varied.

Modified impedance source inverter for power conditioning system

Indian Academy of Sciences (India)

DC link voltage boost, reduced total harmonic distortion of output current and voltage, better voltage gain and wide range of output voltage controlcan be achieved easily with improved power quality. Experimental set-up of the modified impedance source inverter with Field Programmable Gate Array (FPGA) controller has ...

Thulium heat source for high-endurance and high-energy density power systems

International Nuclear Information System (INIS)

Walter, C.E.; Kammeraad, J.E.; Van Konynenburg, R.; VanSant, J.H.

1991-05-01

We are studying the performance characteristics of radioisotope heat source designs for high-endurance and high-energy-density power systems that use thulium-170. Heat sources in the power range of 5--50 kW th coupled with a power conversion efficiency of ∼30%, can easily satisfy current missions for autonomous underwater vehicles. New naval missions will be possible because thulium isotope power systems have a factor of one-to-two hundred higher endurance and energy density than chemical and electrochemical systems. Thulium-170 also has several other attractive features, including the fact that it decays to stable ytterbium-170 with a half-life of four months. For terrestrial applications, refueling on that time scale should be acceptable in view of the advantage of its benign decay. The heat source designs we are studying account for the requirements of isotope production, shielding, and integration with power conversion components. These requirements are driven by environmental and safety considerations. Thulium is present in the form of thin refractory thulia disks that allow power conversion at high peak temperature. We give estimates of power system state points, performance, mass, and volume characteristics. Monte Carlo radiation analysis provides a detailed assessment of shield requirements and heat transfer under normal and distressed conditions is also considered. 11 refs., 7 figs., 4 tabs

The Effect of High-Intensity Intermittent Exercise on Body Composition of Overweight Young Males

Directory of Open Access Journals (Sweden)

M. Heydari

2012-01-01

Full Text Available To determine the effect of a 12-week high intensity intermittent exercise (HIIE intervention on total body, abdominal, trunk, visceral fat mass, and fat free mass of young overweight males. Participants were randomly assigned to either exercise or control group. The intervention group received HIIE three times per week, 20 min per session, for 12 weeks. Aerobic power improved significantly (P0.05 occurred in levels of insulin, HOMA-IR, and blood lipids. Twelve weeks of HIIE resulted in significant reductions in total, abdominal, trunk, and visceral fat and significant increases in fat free mass and aerobic power.

Models for the modern power grid

Science.gov (United States)

Nardelli, Pedro H. J.; Rubido, Nicolas; Wang, Chengwei; Baptista, Murilo S.; Pomalaza-Raez, Carlos; Cardieri, Paulo; Latva-aho, Matti

2014-10-01

This article reviews different kinds of models for the electric power grid that can be used to understand the modern power system, the smart grid. From the physical network to abstract energy markets, we identify in the literature different aspects that co-determine the spatio-temporal multilayer dynamics of power system. We start our review by showing how the generation, transmission and distribution characteristics of the traditional power grids are already subject to complex behaviour appearing as a result of the the interplay between dynamics of the nodes and topology, namely synchronisation and cascade effects. When dealing with smart grids, the system complexity increases even more: on top of the physical network of power lines and controllable sources of electricity, the modernisation brings information networks, renewable intermittent generation, market liberalisation, prosumers, among other aspects. In this case, we forecast a dynamical co-evolution of the smart grid and other kind of networked systems that cannot be understood isolated. This review compiles recent results that model electric power grids as complex systems, going beyond pure technological aspects. From this perspective, we then indicate possible ways to incorporate the diverse co-evolving systems into the smart grid model using, for example, network theory and multi-agent simulation.

Intermittent Testicular Torsion

African Journals Online (AJOL)

2017-06-02

Jun 2, 2017 ... had prior episodes of testicular pain, suggesting that they may have had intermittent torsion before .... None of the patients had antecedent history of sexual exposure, fever, or urinary tract infection .... torsion of the spermatic cord portends an increased risk of acute testicular infarction. J Urol 2008;180 4 ...

Compact, self-regulating nuclear power source

International Nuclear Information System (INIS)

Peterson, Otis G.; Kimpland, Robert H.

2008-01-01

An inherently safe nuclear power source has been designed, that is self-stabilizing and requires no moving mechanical components. Unlike conventional designs, the proposed reactor is self-regulating through the inherent properties of uranium hydride, which serves as a combination fuel and moderator. The temperature driven mobility of the hydrogen contained in the hydride will control the nuclear activity. If the core temperature increases over the set point, the hydrogen is driven out of the core, the moderation drops and the power production decreases. If the temperature drops, the hydrogen returns and the process is reversed. Thus the design is inherently fail-safe and requires only minimal human oversight. The compact nature and inherent safety opens the possibility for low-cost mass production and operation of the reactors. This design has the capability to dramatically alter the manner in which nuclear energy is harnessed for commercial use. (author)

Effect of Intermittent Hypercapnia on Respiratory Control in Rat Pups

Science.gov (United States)

Steggerda, Justin A.; Mayer, Catherine A.; Martin, Richard J.; Wilson, Christopher G.

2010-01-01

Preterm infants are subject to fluctuations in blood gas status associated with immature respiratory control. Intermittent hypoxia during early postnatal life has been shown to increase chemoreceptor sensitivity and destabilize the breathing pattern; however, intermittent hypercapnia remains poorly studied. Therefore, to test the hypothesis that intermittent hypercapnia results in altered respiratory control, we examined the effects of daily exposure to intermittent hypercapnia on the ventilatory response to subsequent hypercapnic and hypoxic exposure in neonatal rat pups. Exposure cycles consisted of 5 min of intermittent hypercapnia (5% CO2, 21% O2, balance N2) followed by 10 min of normoxia. Rat pups were exposed to 18 exposure cycles each day for 1 week, from postnatal day 7 to 14. We analyzed diaphragm electromyograms (EMGs) from pups exposed to subsequent acute hypercapnic (5% CO2) and hypoxic (12% O2) challenges. In response to a subsequent hypercapnia challenge, there was no significant difference in the ventilatory response between control and intermittent hypercapnia-exposed groups. In contrast, intermittent hypercapnia-exposed rat pups showed an enhanced ventilatory response to hypoxic challenge with an increase in minute EMG to 118 ± 14% of baseline versus 107 ± 13% for control pups (p < 0.05). We speculate that prior hypercapnic exposure may increase peripheral chemoreceptor response to subsequent hypoxic exposures and result in perturbed neonatal respiratory control. PMID:19752577

Power Controllability of Three-phase Converter with Unbalanced AC Source

DEFF Research Database (Denmark)

Ma, Ke; Chen, Wenjie; Liserre, Marco

2015-01-01

Three-phase DC-AC power converters suffer from power oscillation and overcurrent problems in case of unbalanced AC source voltage that can be caused by grid/generator faults. Existing solutions to handle these problems are properly selecting and controlling the positive and negative sequence...... currents. In this work a new series of control strategies which utilize the zerosequence components are proposed to enhance the power control ability under this adverse condition. It is concluded that by introducing proper zero sequence current controls and corresponding circuit configurations, the power...... converter can enable more flexible control targets, achieving better performances in the delivered power and load current when suffering from unbalanced AC voltage....

Low Power Consumption Wireless Sensor Communication System Integrated with an Energy Harvesting Power Source

Directory of Open Access Journals (Sweden)

Vlad MARSIC

2013-01-01

Full Text Available This paper presents the testing results of a wireless sensor communication system with low power consumption integrated with an energy harvesting power source. The experiments focus on the system’s capability to perform continuous monitoring and to wirelessly transmit the data acquired from the sensors to a user base station, for realization of completely battery-free wireless sensor system. Energy harvesting technologies together with system design optimization for power consumption minimization ensure the system’s energy autonomous capability demonstrated in this paper by presenting the promising testing results achieved following its integration with structural health monitoring and body area network applications.

Intermittent Hypoxia Causes Inflammation and Injury to Human Adult Cardiac Myocytes.

Science.gov (United States)

Wu, Jing; Stefaniak, Joanna; Hafner, Christina; Schramel, Johannes Peter; Kaun, Christoph; Wojta, Johann; Ullrich, Roman; Tretter, Verena Eva; Markstaller, Klaus; Klein, Klaus Ulrich

2016-02-01

Intermittent hypoxia may occur in a number of clinical scenarios, including interruption of myocardial blood flow or breathing disorders such as obstructive sleep apnea. Although intermittent hypoxia has been linked to cardiovascular and cerebrovascular disease, the effect of intermittent hypoxia on the human heart is not fully understood. Therefore, in the present study, we compared the cellular responses of cultured human adult cardiac myocytes (HACMs) exposed to intermittent hypoxia and different conditions of continuous hypoxia and normoxia. HACMs were exposed to intermittent hypoxia (0%-21% O2), constant mild hypoxia (10% O2), constant severe hypoxia (0% O2), or constant normoxia (21% O2), using a novel cell culture bioreactor with gas-permeable membranes. Cell proliferation, lactate dehydrogenase release, vascular endothelial growth factor release, and cytokine (interleukin [IL] and macrophage migration inhibitory factor) release were assessed at baseline and after 8, 24, and 72 hours of exposure. A signal transduction pathway finder array was performed to determine the changes in gene expression. In comparison with constant normoxia and constant mild hypoxia, intermittent hypoxia induced earlier and greater inflammatory response and extent of cell injury as evidenced by lower cell numbers and higher lactate dehydrogenase, vascular endothelial growth factor, and proinflammatory cytokine (IL-1β, IL-6, IL-8, and macrophage migration inhibitory factor) release. Constant severe hypoxia showed more detrimental effects on HACMs at later time points. Pathway analysis demonstrated that intermittent hypoxia primarily altered gene expression in oxidative stress, Wnt, Notch, and hypoxia pathways. Intermittent and constant severe hypoxia, but not constant mild hypoxia or normoxia, induced inflammation and cell injury in HACMs. Cell injury occurred earliest and was greatest after intermittent hypoxia exposure. Our in vitro findings suggest that intermittent hypoxia

Source term estimation during incident response to severe nuclear power plant accidents

International Nuclear Information System (INIS)

McKenna, T.J.; Glitter, J.G.

1988-10-01

This document presents a method of source term estimation that reflects the current understanding of source term behavior and that can be used during an event. The various methods of estimating radionuclide release to the environment (source terms) as a result of an accident at a nuclear power reactor are discussed. The major factors affecting potential radionuclide releases off site (source terms) as a result of nuclear power plant accidents are described. The quantification of these factors based on plant instrumentation also is discussed. A range of accident conditions from those within the design basis to the most severe accidents possible are included in the text. A method of gross estimation of accident source terms and their consequences off site is presented. 39 refs., 48 figs., 19 tabs

Intermittent, Non Cyclic Severe Mechanical Aortic Valve Regurgitation