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Sample records for nanoflare distribution generated

  1. Active region emission measure distributions and implications for nanoflare heating

    SciTech Connect

    Cargill, P. J.

    2014-03-20

    The temperature dependence of the emission measure (EM) in the core of active regions coronal loops is an important diagnostic of heating processes. Observations indicate that EM(T) ∼ T{sup a} below approximately 4 MK, with 2 < a < 5. Zero-dimensional hydrodynamic simulations of nanoflare trains are used to demonstrate the dependence of a on the time between individual nanoflares (T{sub N} ) and the distribution of nanoflare energies. If T{sub N} is greater than a few thousand seconds, a < 3. For smaller values, trains of equally spaced nanoflares cannot account for the observed range of a if the distribution of nanoflare energies is either constant, randomly distributed, or a power law. Power law distributions where there is a delay between consecutive nanoflares proportional to the energy of the second nanoflare do lead to the observed range of a. However, T{sub N} must then be of the order of hundreds to no more than a few thousand seconds. If a nanoflare leads to the relaxation of a stressed coronal field to a near-potential state, the time taken to build up the required magnetic energy is thus too long to account for the EM measurements. Instead, it is suggested that a nanoflare involves the relaxation from one stressed coronal state to another, dissipating only a small fraction of the available magnetic energy. A consequence is that nanoflare energies may be smaller than previously envisioned.

  2. Active Region Emission Measure Distributions and Implications for Nanoflare Heating

    NASA Astrophysics Data System (ADS)

    Cargill, P. J.

    2014-03-01

    The temperature dependence of the emission measure (EM) in the core of active regions coronal loops is an important diagnostic of heating processes. Observations indicate that EM(T) ~ Ta below approximately 4 MK, with 2 < a < 5. Zero-dimensional hydrodynamic simulations of nanoflare trains are used to demonstrate the dependence of a on the time between individual nanoflares (TN ) and the distribution of nanoflare energies. If TN is greater than a few thousand seconds, a < 3. For smaller values, trains of equally spaced nanoflares cannot account for the observed range of a if the distribution of nanoflare energies is either constant, randomly distributed, or a power law. Power law distributions where there is a delay between consecutive nanoflares proportional to the energy of the second nanoflare do lead to the observed range of a. However, TN must then be of the order of hundreds to no more than a few thousand seconds. If a nanoflare leads to the relaxation of a stressed coronal field to a near-potential state, the time taken to build up the required magnetic energy is thus too long to account for the EM measurements. Instead, it is suggested that a nanoflare involves the relaxation from one stressed coronal state to another, dissipating only a small fraction of the available magnetic energy. A consequence is that nanoflare energies may be smaller than previously envisioned.

  3. Energy distribution of nanoflares in the quiet solar corona

    NASA Astrophysics Data System (ADS)

    Ulyanov, Artyom

    2012-07-01

    We present a detailed statistical analysis of flare-like events in low layer of solar corona detected with TESIS instrument onboard CORONAS-PHOTON satellite in 171 {Å} during high-cadence (5 sec) time-series. The estimated thermal energies of these small events amount to 10^{23} - 10^{26} erg. According to modern classification flare-like events with such energies are usually referred to as nanoflares. The big number of registered events (above 2000) allowed us to obtain precise distributions of geometric and physical parameters of nanoflares, the most intriguing being energy distribution. Following Aschwanden et al. (2000) and other authors we approximated the calculated energy distribution with a single power law slope: N(E)dE ˜ N^{-α}dE. The power law index was derived to be α = 2.4 ± 0.2, which is very close to the value reported by Krucker & Benz (1998): α ≈ 2.3 - 2.4. The total energy input from registered events constitute about 10^4 erg \\cdot cm^{-2} \\cdot s^{-1}, which is well beyond net losses in quiet corona (3 \\cdot 10^5 erg \\cdot cm^{-2} \\cdot s^{-1}). However, the value of α > 2 indicates that nanoflares with lower energies dominate over nanoflares with bigger energies and could contribute considerably to quiet corona heating.

  4. CAN A LONG NANOFLARE STORM EXPLAIN THE OBSERVED EMISSION MEASURE DISTRIBUTIONS IN ACTIVE REGION CORES?

    SciTech Connect

    Mulu-Moore, Fana M.; Winebarger, Amy R.; Warren, Harry P.

    2011-11-20

    All theories that attempt to explain the heating of the high-temperature plasma observed in the solar corona are based on short bursts of energy. The intensities and velocities measured in the cores of quiescent active regions, however, can be steady over many hours of observation. One heating scenario that has been proposed to reconcile such observations with impulsive heating models is the 'long nanoflare storm', where short-duration heating events occur infrequently on many sub-resolution strands; the emission of the strands is then averaged together to explain the observed steady structures. In this Letter, we examine the emission measure distribution predicted for such a long nanoflare storm by modeling an arcade of strands in an active region core. Comparisons of the computed emission measure distributions with recent observations indicate that the long nanoflare storm scenario implies greater than five times more 1 MK emission than is actually observed for all plausible combinations of loop lengths, heating rates, and abundances. We conjecture that if the plasma had 'super coronal' abundances, the model may be able to match the observations at low temperatures.

  5. THE ORIGIN OF NON-MAXWELLIAN SOLAR WIND ELECTRON VELOCITY DISTRIBUTION FUNCTION: CONNECTION TO NANOFLARES IN THE SOLAR CORONA

    SciTech Connect

    Che, H.; Goldstein, M. L.

    2014-11-10

    The formation of the observed core-halo feature in the solar wind electron velocity distribution function is a long-time puzzle. In this Letter, based on the current knowledge of nanoflares, we show that the nanoflare-accelerated electron beams are likely to trigger a strong electron two-stream instability that generates kinetic Alfvén wave and whistler wave turbulence, as we demonstrated in a previous paper. We further show that the core-halo feature produced during the origin of kinetic turbulence is likely to originate in the inner corona and can be preserved as the solar wind escapes to space along open field lines. We formulate a set of equations to describe the heating processes observed in the simulation and show that the core-halo temperature ratio of the solar wind is insensitive to the initial conditions in the corona and is related to the core-halo density ratio of the solar wind and to the quasi-saturation property of the two-stream instability at the time when the exponential decay ends. This relation can be extended to the more general core-halo-strahl feature in the solar wind. The temperature ratio between the core and hot components is nearly independent of the heliospheric distance to the Sun. We show that the core-halo relative drift previously reported is a relic of the fully saturated two-stream instability. Our theoretical results are consistent with the observations while new tests for this model are provided.

  6. Distribution of Nanoflares as Spatially Resolved Current Sheets in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Ng, C. S.; Lin, L.

    2014-05-01

    In a recent numerical study [Ng et al., Astrophys. J. 747, 109, 2012], based on a three-dimensional model of coronal heating using reduced magnetohydrodynamics, we have obtained scaling results of heating rate versus Lundquist number S based on a series of runs in which random photospheric motions are imposed for hundreds to thousands of Alfvén time in order to obtain converged statistical values. The heating rate found in these simulations saturates to a level that is independent of S in the high S limit and is consistent with the required level for coronal heating. In a previous study based on the total heating rate time series [Ng and Lin, AIP Conf. Proc. 1500, 38, 2012] in these simulations, we have also calculated heating events distributions, which are consistent with observations but do not support the nanoflares scenario [Parker, Astrophys. J. 330, 474, 1988]. This method has a limitation of not distinguishing individual heating events. We now extend this analysis to investigate the distribution of energy release events defined as spatially resolved current sheets [Lin et el., ASP Conf. Ser. 474, 159, 2013]. We report preliminary results and compare to results obtained using only time-series analysis.

  7. Can the Nanoflare Model Reproduce Observed Emissions?

    NASA Technical Reports Server (NTRS)

    Mulu-Moore, Fana M.; Winebarger, Amy R.; Warren, Harry P.

    2011-01-01

    All theories that attempt to explain the high temperatures observed in the solar corona are based on short bursts of energy release. The intensities and velocities measured in the core of an active, however, can be steady over many hours of observation. One heating scenario that has been proposed to reconcile such observations with models is the "long nanoflare storm," where short duration heating events occur infrequently on many sub-resolutions strands. In this Letter, we examine the emission measure distribution predicted for such a heating scenario by modeling an arcade of strands in an active region core. Comparisons of the computed emission measure distributions with recent observations indicate that that the long nanoflare storm scenario implies much more 1 MK emission than is actually observed for all plausible combinations of loop lengths, heating rates, and abundances. We conjecture that if the plasma had super coronal abundances, the model may be able to match the observations at low temperatures.

  8. Nanoflare activity in the solar chromosphere

    SciTech Connect

    Jess, D. B.; Mathioudakis, M.; Keys, P. H.

    2014-11-10

    We use ground-based images of high spatial and temporal resolution to search for evidence of nanoflare activity in the solar chromosphere. Through close examination of more than 1 × 10{sup 9} pixels in the immediate vicinity of an active region, we show that the distributions of observed intensity fluctuations have subtle asymmetries. A negative excess in the intensity fluctuations indicates that more pixels have fainter-than-average intensities compared with those that appear brighter than average. By employing Monte Carlo simulations, we reveal how the negative excess can be explained by a series of impulsive events, coupled with exponential decays, that are fractionally below the current resolving limits of low-noise equipment on high-resolution ground-based observatories. Importantly, our Monte Carlo simulations provide clear evidence that the intensity asymmetries cannot be explained by photon-counting statistics alone. A comparison to the coronal work of Terzo et al. suggests that nanoflare activity in the chromosphere is more readily occurring, with an impulsive event occurring every ∼360 s in a 10,000 km{sup 2} area of the chromosphere, some 50 times more events than a comparably sized region of the corona. As a result, nanoflare activity in the chromosphere is likely to play an important role in providing heat energy to this layer of the solar atmosphere.

  9. Are chromospheric nanoflares a primary source of coronal plasma?

    SciTech Connect

    Klimchuk, J. A.; Bradshaw, S. J. E-mail: stephen.bradshaw@rice.edu

    2014-08-10

    It has been suggested that the hot plasma of the solar corona comes primarily from impulsive heating events, or nanoflares, that occur in the lower atmosphere, either in the upper part of the ordinary chromosphere or at the tips of type II spicules. We test this idea with a series of hydrodynamic simulations. We find that synthetic Fe XII (195) and Fe XIV (274) line profiles generated from the simulations disagree dramatically with actual observations. The integrated line intensities are much too faint; the blueshifts are much too fast; the blue-red asymmetries are much too large; and the emission is confined to low altitudes. We conclude that chromospheric nanoflares are not a primary source of hot coronal plasma. Such events may play an important role in producing the chromosphere and powering its intense radiation, but they do not, in general, raise the temperature of the plasma to coronal values. Those cases where coronal temperatures are reached must be relatively uncommon. The observed profiles of Fe XII and Fe XIV come primarily from plasma that is heated in the corona itself, either by coronal nanoflares or a quasi-steady coronal heating process. Chromospheric nanoflares might play a role in generating waves that provide this coronal heating.

  10. Modeling Chromospheric Nanoflares with HYDRAD

    NASA Astrophysics Data System (ADS)

    Reep, J. W.; Warren, H. P.

    2015-12-01

    Observational advances with IRIS have given the ability to observe details of the coronal transition region (TR) with extremely high spatial resolution. Spectral lines formed in the TR, in particular, illuminate the dynamics of mass and energy flow between the chromosphere and corona. Using a sophisticated hydrodynamic model, we simulate nanoflares driven by different heating mechanisms - electron beams, in situ thermal heating, and Alfvenic waves. By examining the atmospheric response and by forward modeling of spectral lines, we can directly compare with observations of the TR in order to differentiate potential heating mechanisms. We thus present the results of a large, systematic investigation of the parameter space of chromospheric nanoflares. We discuss similarities and differences predicted by the different heating mechanisms, all within the context of observed quantities.

  11. "Hot" Non-flaring Plasmas in Active Region Cores Heated by Single Nanoflares

    NASA Astrophysics Data System (ADS)

    Barnes, Will Thomas; Cargill, Peter; Bradshaw, Stephen

    2016-05-01

    We use hydrodynamic modeling tools, including a two-fluid development of the EBTEL code, to investigate the properties expected of "hot" (i.e. between 106.7 and 107.2 K) non-flaring plasmas due to nanoflare heating in active regions. Here we focus on single nanoflares and show that while simple models predict an emission measure distribution extending well above 10 MK that is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium and, for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the "smoking gun" of nanoflare heating, lies between 1 MK and 10 MK. Signatures of the actual heating may be detectable in some instances.

  12. Investigation of relationships between parameters of solar nano-flares and solar activity

    NASA Astrophysics Data System (ADS)

    Safari, Hossein; Javaherian, Mohsen; Kaki, Bardia

    2016-07-01

    Solar flares are one of the important coronal events which are originated in solar magnetic activity. They release lots of energy during the interstellar medium, right after the trigger. Flare prediction can play main role in avoiding eventual damages on the Earth. Here, to interpret solar large-scale events (e.g., flares), we investigate relationships between small-scale events (nano-flares) and large-scale events (e.g., flares). In our method, by using simulations of nano-flares based on Monte Carlo method, the intensity time series of nano-flares are simulated. Then, the solar full disk images taken at 171 angstrom recorded by SDO/AIA are employed. Some parts of the solar disk (quiet Sun (QS), coronal holes (CHs), and active regions (ARs)) are cropped and the time series of these regions are extracted. To compare the simulated intensity time series of nano-flares with the intensity time series of real data extracted from different parts of the Sun, the artificial neural networks is employed. Therefore, we are able to extract physical parameters of nano-flares like both kick and decay rate lifetime, and the power of their power-law distributions. The procedure of variations in the power value of power-law distributions within QS, CH is similar to AR. Thus, by observing the small part of the Sun, we can follow the procedure of solar activity.

  13. Inference of Heating Properties from "Hot" Non-flaring Plasmas in Active Region Cores. I. Single Nanoflares

    NASA Astrophysics Data System (ADS)

    Barnes, W. T.; Cargill, P. J.; Bradshaw, S. J.

    2016-09-01

    The properties that are expected of “hot” non-flaring plasmas due to nanoflare heating in active regions are investigated using hydrodynamic modeling tools, including a two-fluid development of the Enthalpy Based Thermal Evolution of Loops code. Here we study a single nanoflare and show that while simple models predict an emission measure distribution extending well above 10 MK, which is consistent with cooling by thermal conduction, many other effects are likely to limit the existence and detectability of such plasmas. These include: differential heating between electrons and ions, ionization non-equilibrium, and for short nanoflares, the time taken for the coronal density to increase. The most useful temperature range to look for this plasma, often called the “smoking gun” of nanoflare heating, lies between 106.6 and 107 K. Signatures of the actual heating may be detectable in some instances.

  14. Evidence of Nanoflare Heating in Coronal Loops Observed with Hinolde-XRT and SDO-AIA

    NASA Technical Reports Server (NTRS)

    Lopez-Fuentes, M. C.; Klimchuk, James

    2013-01-01

    We study a series of coronal loop lightcurves from X-ray and EUV observations. In search for signatures of nanoflare heating, we analyze the statistical properties of the observed lightcurves and compare them with synthetic cases obtained with a 2D cellular-automaton model based on nanoflare heating driven by photospheric motions. Our analysis shows that the observed and the model lightcurves have similar statistical properties. The asymmetries observed in the distribution of the intensity fluctuations indicate the possible presence of widespread cooling processes in sub-resolution magnetic strands.

  15. Distributed generation systems model

    SciTech Connect

    Barklund, C.R.

    1994-12-31

    A slide presentation is given on a distributed generation systems model developed at the Idaho National Engineering Laboratory, and its application to a situation within the Idaho Power Company`s service territory. The objectives of the work were to develop a screening model for distributed generation alternatives, to develop a better understanding of distributed generation as a utility resource, and to further INEL`s understanding of utility concerns in implementing technological change.

  16. Widespread Nanoflare Variability Detected with Hinode/XRT in a Solar Active Region

    NASA Technical Reports Server (NTRS)

    Reale, Fabio; Terzo, Sergio; Miceli, Marco; Klimchuk, James A.; Kano, Ryouhei; Tsuneta, Saku

    2011-01-01

    It is generally agreed that small impulsive energy bursts called nanoflares are responsible for at least some of the Sun s hot corona, but whether they are the explanation for most of the multi-million degree plasma has been a matter of ongoing debate. We here present evidence that nanoflares are widespread in an active region observed by the X-Ray Telescope on-board the Hinode mission. The distributions of intensity fluctuations have small but important asymmetries, whether taken from individual pixels, multi-pixel subregions, or the entire active region. Negative fluctuations (corresponding to reduced intensity) are greater in number but weaker in amplitude, so that the median fluctuation is negative compared to a mean of zero. Using Monte Carlo simulations, we show that only part of this asymmetry can be explained by Poisson photon statistics. The remainder is explainable with a tendency for exponentially decreasing intensity, such as would be expected from a cooling plasma produced, e.g., from a nanoflare. We suggest that nanoflares are a universal heating process within active regions.

  17. Nanoflare Heating of Solar and Stellar Coronae

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.

    2010-01-01

    A combination of observational and theoretical evidence suggests that much, and perhaps most, of the Sun's corona is heated by small unresolved bursts of energy called nanoflares. It seems likely that stellar coronae are heated in a similar fashion. Kanoflares are here taken to mean any impulsive heating that occurs within a magnetic flux strand. Many mechanisms have this property, including waves, but we prefer Parker's picture of tangled magnetic fields. The tangling is caused by turbulent convection at the stellar surface, and magnetic energy is released when the stresses reach a critical level. We suggest that the mechanism of energy release is the "secondary instability" of electric current sheets that are present at the boundaries between misaligned strands. I will discuss the collective evidence for solar and stellar nanoflares and hopefully present new results from the Solar Dynamics Observatory that was just launched.

  18. GASIFICATION FOR DISTRIBUTED GENERATION

    SciTech Connect

    Ronald C. Timpe; Michael D. Mann; Darren D. Schmidt

    2000-05-01

    A recent emphasis in gasification technology development has been directed toward reduced-scale gasifier systems for distributed generation at remote sites. The domestic distributed power generation market over the next decade is expected to be 5-6 gigawatts per year. The global increase is expected at 20 gigawatts over the next decade. The economics of gasification for distributed power generation are significantly improved when fuel transport is minimized. Until recently, gasification technology has been synonymous with coal conversion. Presently, however, interest centers on providing clean-burning fuel to remote sites that are not necessarily near coal supplies but have sufficient alternative carbonaceous material to feed a small gasifier. Gasifiers up to 50 MW are of current interest, with emphasis on those of 5-MW generating capacity. Internal combustion engines offer a more robust system for utilizing the fuel gas, while fuel cells and microturbines offer higher electric conversion efficiencies. The initial focus of this multiyear effort was on internal combustion engines and microturbines as more realistic near-term options for distributed generation. In this project, we studied emerging gasification technologies that can provide gas from regionally available feedstock as fuel to power generators under 30 MW in a distributed generation setting. Larger-scale gasification, primarily coal-fed, has been used commercially for more than 50 years to produce clean synthesis gas for the refining, chemical, and power industries. Commercial-scale gasification activities are under way at 113 sites in 22 countries in North and South America, Europe, Asia, Africa, and Australia, according to the Gasification Technologies Council. Gasification studies were carried out on alfalfa, black liquor (a high-sodium waste from the pulp industry), cow manure, and willow on the laboratory scale and on alfalfa, black liquor, and willow on the bench scale. Initial parametric tests

  19. Nanoflare Heating of the Quiet Sun

    NASA Astrophysics Data System (ADS)

    Viall, N. M.; Klimchuk, J. A.

    2015-12-01

    How the solar corona is heated to temperatures of over 1 MK, while the photosphere below is only ~ 6000 K remains one of the outstanding problems in all of space science. Solving this problem is crucial for understanding Sun-Earth connections, and will provide new insight into universal processes such as magnetic reconnection and wave-particle interactions. We use a systematic technique to analyze the properties of coronal heating throughout the solar corona using data taken with the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. Our technique computes cooling times of the coronal plasma on a pixel-by-pixel basis and has the advantage that it analyzes all of the coronal emission, including the diffuse emission surrounding distinguishable coronal features. We have already applied this technique to 15 different active regions, and find clear evidence for dynamic heating and cooling cycles that are consistent with the 'impulsive nanoflare' scenario. What about the rest of the Solar corona? Whether the quiet Sun is heated in a similar or distinct manner from active regions is a matter of great debate. Here we apply our coronal heating analysis technique to quiet Sun locations. We find areas of quiet Sun locations that also undergo dynamic heating and cooling cycles, consistent with impulsive nanoflares. However, there are important characteristics that are distinct from those of active regions.

  20. OBSERVING CORONAL NANOFLARES IN ACTIVE REGION MOSS

    SciTech Connect

    Testa, Paola; DeLuca, Ed; Golub, Leon; Korreck, Kelly; Weber, Mark; De Pontieu, Bart; Martinez-Sykora, Juan; Title, Alan; Hansteen, Viggo; Cirtain, Jonathan; Winebarger, Amy; Kobayashi, Ken; Kuzin, Sergey; Walsh, Robert; DeForest, Craig

    2013-06-10

    The High-resolution Coronal Imager (Hi-C) has provided Fe XII 193A images of the upper transition region moss at an unprecedented spatial ({approx}0.''3-0.''4) and temporal (5.5 s) resolution. The Hi-C observations show in some moss regions variability on timescales down to {approx}15 s, significantly shorter than the minute-scale variability typically found in previous observations of moss, therefore challenging the conclusion of moss being heated in a mostly steady manner. These rapid variability moss regions are located at the footpoints of bright hot coronal loops observed by the Solar Dynamics Observatory/Atmospheric Imaging Assembly in the 94 A channel, and by the Hinode/X-Ray Telescope. The configuration of these loops is highly dynamic, and suggestive of slipping reconnection. We interpret these events as signatures of heating events associated with reconnection occurring in the overlying hot coronal loops, i.e., coronal nanoflares. We estimate the order of magnitude of the energy in these events to be of at least a few 10{sup 23} erg, also supporting the nanoflare scenario. These Hi-C observations suggest that future observations at comparable high spatial and temporal resolution, with more extensive temperature coverage, are required to determine the exact characteristics of the heating mechanism(s).

  1. Chromospheric Nanoflares as a Source of Coronal Plasma. II. Repeating Nanoflares

    NASA Astrophysics Data System (ADS)

    Bradshaw, S. J.; Klimchuk, J. A.

    2015-10-01

    The million degree plasma of the solar corona must be supplied by the underlying layers of the atmosphere. The mechanism and location of energy release, and the precise source of coronal plasma, remain unresolved. In earlier work, we pursued the idea that warm plasma is supplied to the corona via direct heating of the chromosphere by nanoflares, contrary to the prevailing belief that the corona is heated in situ and the chromosphere is subsequently energized and ablated by thermal conduction. We found that single (low-frequency) chromospheric nanoflares could not explain the observed intensities, Doppler-shifts, and red/blue asymmetries in Fe xii and xiv emission lines. In the present work, we follow up on another suggestion that the corona could be powered by chromospheric nanoflares that repeat on a timescale substantially shorter than the cooling/draining timescale. That is, a single magnetic strand is re-supplied with coronal plasma before the existing plasma has time to cool and drain. We perform a series of hydrodynamic experiments and predict the Fe xii and xiv line intensities, Doppler-shifts, and red/blue asymmetries. We find that our predicted quantities disagree dramatically with observations and fully developed loop structures cannot be created by intermediate- or high-frequency chromospheric nanoflares. We conclude that the mechanism ultimately responsible for producing coronal plasma operates above the chromosphere, but this does not preclude the possibility of a similar mechanism powering the chromosphere, extreme examples of which may be responsible for heating chromospheric plasma to transition region temperatures (e.g., type II spicules).

  2. CHROMOSPHERIC NANOFLARES AS A SOURCE OF CORONAL PLASMA. II. REPEATING NANOFLARES

    SciTech Connect

    Bradshaw, S. J.; Klimchuk, J. A. E-mail: James.A.Klimchuk@nasa.gov

    2015-10-01

    The million degree plasma of the solar corona must be supplied by the underlying layers of the atmosphere. The mechanism and location of energy release, and the precise source of coronal plasma, remain unresolved. In earlier work, we pursued the idea that warm plasma is supplied to the corona via direct heating of the chromosphere by nanoflares, contrary to the prevailing belief that the corona is heated in situ and the chromosphere is subsequently energized and ablated by thermal conduction. We found that single (low-frequency) chromospheric nanoflares could not explain the observed intensities, Doppler-shifts, and red/blue asymmetries in Fe xii and xiv emission lines. In the present work, we follow up on another suggestion that the corona could be powered by chromospheric nanoflares that repeat on a timescale substantially shorter than the cooling/draining timescale. That is, a single magnetic strand is re-supplied with coronal plasma before the existing plasma has time to cool and drain. We perform a series of hydrodynamic experiments and predict the Fe xii and xiv line intensities, Doppler-shifts, and red/blue asymmetries. We find that our predicted quantities disagree dramatically with observations and fully developed loop structures cannot be created by intermediate- or high-frequency chromospheric nanoflares. We conclude that the mechanism ultimately responsible for producing coronal plasma operates above the chromosphere, but this does not preclude the possibility of a similar mechanism powering the chromosphere, extreme examples of which may be responsible for heating chromospheric plasma to transition region temperatures (e.g., type II spicules)

  3. A Survey of Nanoflare Properties in Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Viall, N. M.; Klimchuk, J. A.

    2013-12-01

    We investigate coronal heating using a systematic technique to analyze the properties of nanoflares in active regions (AR). Our technique computes cooling times, or time-lags, on a pixel-by-pixel basis using data taken with the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. Our technique has the advantage that it allows us to analyze all of the coronal AR emission, including the so-called diffuse emission. We recently presented results using this time-lag analysis on NOAA AR 11082 (Viall & Klimchuk 2012) and found that the majority of the pixels contained cooling plasma along their line of sight, consistent with impulsive coronal nanoflare heating. Additionally, our results showed that the nanoflare energy is stronger in the AR core and weaker in the active region periphery. Are these results representative of the nanoflare properties exhibited in the majority of ARs, or is AR 11082 unique? Here we present the time-lag results for a survey of ARs and show that these nanoflare patterns are born out in other active regions, for a range of ages, magnetic complexity, and total unsigned magnetic flux. Other aspects of the nanoflare properties, however, turn out to be dependent on certain AR characteristics.

  4. Nanoflare heating model for collisionless solar corona

    NASA Astrophysics Data System (ADS)

    Visakh Kumar, U. L.; Varghese, Bilin Susan; Kurian, P. J.

    2017-02-01

    The problem of coronal heating remains one of the greatest unresolved problems in space science. Magnetic reconnection plays a significant role in heating the solar corona. When two oppositely directed magnetic fields come closer to form a current sheet, the current density of the plasma increases due to which magnetic reconnection and conversion of magnetic energy into thermal energy takes place. The present paper deals with a model for reconnection occurring in the solar corona under steady state in collisionless regime. The model predicts that reconnection time in the solar corona varies inversely with the cube of magnetic field and varies directly with the Lindquist number. Our analysis shows that reconnections are occurring within a time interval of 600 s in the solar corona, producing nanoflares in the energy range 10 21-10 23 erg /s which matches with Yohkoh X-ray observations.

  5. Multiplexed nanoflares: mRNA detection in live cells.

    PubMed

    Prigodich, Andrew E; Randeria, Pratik S; Briley, William E; Kim, Nathaniel J; Daniel, Weston L; Giljohann, David A; Mirkin, Chad A

    2012-02-21

    We report the development of the multiplexed nanoflare, a nanoparticle agent that is capable of simultaneously detecting two distinct mRNA targets inside a living cell. These probes are spherical nucleic acid (SNA) gold nanoparticle (Au NP) conjugates consisting of densely packed and highly oriented oligonucleotide sequences, many of which are hybridized to a reporter with a distinct fluorophore label and each complementary to its corresponding mRNA target. When multiplexed nanoflares are exposed to their targets, they provide a sequence specific signal in both extra- and intracellular environments. Importantly, one of the targets can be used as an internal control, improving detection by accounting for cell-to-cell variations in nanoparticle uptake and background. Compared to single-component nanoflares, these structures allow one to determine more precisely relative mRNA levels in individual cells, improving cell sorting and quantification.

  6. Solar power generation and distribution

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The production of electricity from solar energy is discussed. The economics of the proposed generation and distribution systems are analyzed. The use of photovoltaics for converting solar energy to home heating is proposed. The problems of energy distribution are analyzed from the standpoint of equipment costs and complexity.

  7. Using a nano-flare probe to detect RNA in live donor cells prior to somatic cell nuclear transfer.

    PubMed

    Fu, Bo; Ren, Liang; Liu, Di; Ma, Jian-Zhang; An, Tie-Zhu; Yang, Xiu-Qin; Ma, Hong; Guo, Zhen-Hua; Zhu, Meng; Bai, Jing

    2016-01-01

    Many transgenes are silenced in mammalian cells (donor cells used for somatic cell nuclear transfer [SCNT]). Silencing correlated with a repressed chromatin structure or suppressed promoter, and it impeded the production of transgenic animals. Gene transcription studies in live cells are challenging because of the drawbacks of reverse-transcription polymerase chain reaction and fluorescence in situ hybridization. Nano-flare probes provide an effective approach to detect RNA in living cells. We used 18S RNA, a housekeeping gene, as a reference gene. This study aimed to establish a platform to detect RNA in single living donor cells using a Nano-flare probe prior to SCNT and to verify the safety and validity of the Nano-flare probe in order to provide a technical foundation for rescuing silenced transgenes in transgenic cloned embryos. We investigated cytotoxic effect of the 18S RNA-Nano-flare probe on porcine fetal fibroblasts, characterized the distribution of the 18S RNA-Nano-flare probe in living cells and investigated the effect of the 18S RNA-Nano-flare probe on the development of cloned embryos after SCNT. The cytotoxic effect of the 18S RNA-Nano-flare probe on porcine fetal fibroblasts was dose-dependent, and 18S RNA was detected using the 18S RNA-Nano-flare probe. In addition, treating donor cells with 500 pM 18S RNA-Nano-flare probe did not have adverse effects on the development of SCNT embryos at the pre-implantation stage. In conclusion, we established a preliminary platform to detect RNA in live donor cells using a Nano-flare probe prior to SCNT.

  8. Nanoflares, Spicules, and Other Small-Scale Dynamic Phenomena on the Sun

    NASA Technical Reports Server (NTRS)

    Klimchuk, James

    2010-01-01

    There is abundant evidence of highly dynamic phenomena occurring on very small scales in the solar atmosphere. For example, the observed pr operties of many coronal loops can only be explained if the loops are bundles of unresolved strands that are heated impulsively by nanoflares. Type II spicules recently discovered by Hinode are an example of small-scale impulsive events occurring in the chromosphere. The exist ence of these and other small-scale phenomena is not surprising given the highly structured nature of the magnetic field that is revealed by photospheric observations. Dynamic phenomena also occur on much lar ger scales, including coronal jets, flares, and CMEs. It is tempting to suggest that these different phenomena are all closely related and represent a continuous distribution of sizes and energies. However, this is a dangerous over simplification in my opinion. While it is tru e that the phenomena all involve "magnetic reconnection" (the changin g of field line connectivity) in some form, how this occurs depends s trongly on the magnetic geometry. A nanoflare resulting from the interaction of tangled magnetic strands within a confined coronal loop is much different from a major flare occurring at the current sheet form ed when a CME rips open an active region. I will review the evidence for ubiquitous small-scale dynamic phenomena on the Sun and discuss wh y different phenomena are not all fundamentally the same.

  9. Modelling nanoflares in active regions and implications for coronal heating mechanisms

    PubMed Central

    Cargill, P. J.; Warren, H. P.; Bradshaw, S. J.

    2015-01-01

    Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500–2000 s, (ii) a weak ‘hot’ component (more than 106.6 K) is present, and (iii) nanoflare energies may be as low as a few 1023 ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating. PMID:25897093

  10. Modelling nanoflares in active regions and implications for coronal heating mechanisms.

    PubMed

    Cargill, P J; Warren, H P; Bradshaw, S J

    2015-05-28

    Recent observations from the Hinode and Solar Dynamics Observatory spacecraft have provided major advances in understanding the heating of solar active regions (ARs). For ARs comprising many magnetic strands or sub-loops heated by small, impulsive events (nanoflares), it is suggested that (i) the time between individual nanoflares in a magnetic strand is 500-2000 s, (ii) a weak 'hot' component (more than 10(6.6) K) is present, and (iii) nanoflare energies may be as low as a few 10(23) ergs. These imply small heating events in a stressed coronal magnetic field, where the time between individual nanoflares on a strand is of order the cooling time. Modelling suggests that the observed properties are incompatible with nanoflare models that require long energy build-up (over 10 s of thousands of seconds) and with steady heating.

  11. Evidence of nonthermal particles in coronal loops heated impulsively by nanoflares.

    PubMed

    Testa, P; De Pontieu, B; Allred, J; Carlsson, M; Reale, F; Daw, A; Hansteen, V; Martinez-Sykora, J; Liu, W; DeLuca, E E; Golub, L; McKillop, S; Reeves, K; Saar, S; Tian, H; Lemen, J; Title, A; Boerner, P; Hurlburt, N; Tarbell, T D; Wuelser, J P; Kleint, L; Kankelborg, C; Jaeggli, S

    2014-10-17

    The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High-resolution observations with the Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (~20 to 60 seconds) of intensity and velocity on small spatial scales (≲500 kilometers) at the footpoints of hot and dynamic coronal loops. The observations are consistent with numerical simulations of heating by beams of nonthermal electrons, which are generated in small impulsive (≲30 seconds) heating events called "coronal nanoflares." The accelerated electrons deposit a sizable fraction of their energy (≲10(25) erg) in the chromosphere and TR. Our analysis provides tight constraints on the properties of such electron beams and new diagnostics for their presence in the nonflaring corona.

  12. Evidence of nonthermal particles in coronal loops heated impulsively by nanoflares

    NASA Astrophysics Data System (ADS)

    Testa, P.; De Pontieu, B.; Allred, J.; Carlsson, M.; Reale, F.; Daw, A.; Hansteen, V.; Martinez-Sykora, J.; Liu, W.; DeLuca, E. E.; Golub, L.; McKillop, S.; Reeves, K.; Saar, S.; Tian, H.; Lemen, J.; Title, A.; Boerner, P.; Hurlburt, N.; Tarbell, T. D.; Wuelser, J. P.; Kleint, L.; Kankelborg, C.; Jaeggli, S.

    2014-10-01

    The physical processes causing energy exchange between the Sun’s hot corona and its cool lower atmosphere remain poorly understood. The chromosphere and transition region (TR) form an interface region between the surface and the corona that is highly sensitive to the coronal heating mechanism. High-resolution observations with the Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (~20 to 60 seconds) of intensity and velocity on small spatial scales (≲500 kilometers) at the footpoints of hot and dynamic coronal loops. The observations are consistent with numerical simulations of heating by beams of nonthermal electrons, which are generated in small impulsive (≲30 seconds) heating events called “coronal nanoflares.” The accelerated electrons deposit a sizable fraction of their energy (≲1025 erg) in the chromosphere and TR. Our analysis provides tight constraints on the properties of such electron beams and new diagnostics for their presence in the nonflaring corona.

  13. DIAGNOSING THE TIME DEPENDENCE OF ACTIVE REGION CORE HEATING FROM THE EMISSION MEASURE. II. NANOFLARE TRAINS

    SciTech Connect

    Reep, J. W.; Bradshaw, S. J.; Klimchuk, J. A. E-mail: stephen.bradshaw@rice.edu

    2013-02-20

    The time dependence of heating in solar active regions can be studied by analyzing the slope of the emission measure distribution coolward of the peak. In a previous study we showed that low-frequency heating can account for 0% to 77% of active region core emission measures. We now turn our attention to heating by a finite succession of impulsive events for which the timescale between events on a single magnetic strand is shorter than the cooling timescale. We refer to this scenario as a 'nanoflare train' and explore a parameter space of heating and coronal loop properties with a hydrodynamic model. Our conclusions are (1) nanoflare trains are consistent with 86% to 100% of observed active region cores when uncertainties in the atomic data are properly accounted for; (2) steeper slopes are found for larger values of the ratio of the train duration {Delta} {sub H} to the post-train cooling and draining timescale {Delta} {sub C}, where {Delta} {sub H} depends on the number of heating events, the event duration and the time interval between successive events ({tau} {sub C}); (3) {tau} {sub C} may be diagnosed from the width of the hot component of the emission measure provided that the temperature bins are much smaller than 0.1 dex; (4) the slope of the emission measure alone is not sufficient to provide information about any timescale associated with heating-the length and density of the heated structure must be measured for {Delta} {sub H} to be uniquely extracted from the ratio {Delta} {sub H}/{Delta} {sub C}.

  14. Nanoflare vs Footpoint Heating : Observational Signatures

    NASA Technical Reports Server (NTRS)

    Winebarger, Amy; Alexander, Caroline; Lionello, Roberto; Linker, Jon; Mikic, Zoran; Downs, Cooper

    2015-01-01

    Time lag analysis shows very long time lags between all channel pairs. Impulsive heating cannot address these long time lags. 3D Simulations of footpoint heating shows a similar pattern of time lags (magnitude and distribution) to observations. Time lags and relative peak intensities may be able to differentiate between TNE and impulsive heating solutions. Adding a high temperature channel (like XRT Be-­thin) may improve diagnostics.

  15. Reliability evaluation of distribution systems containing renewable distributed generations

    NASA Astrophysics Data System (ADS)

    Alkuhayli, Abdulaziz Abddullah

    Reliability evaluation of distribution networks, including islanded microgrid cases, is presented. The Monte Carlo simulation algorithm is applied to a test network. The network includes three types of distributed energy resources solar photovoltaic (PV), wind turbine (WT) and gas turbine (GT). These distributed generators contribute to supply part of the load during grid-connected mode, but supply the entire load during islanded microgrid operation. PV and WT stochastic models have been used to simulate the randomness of these resources. This study shows that the implementation of distributed generations can improve the reliability of the distribution networks.

  16. Distributed generation - the fuel processing example

    SciTech Connect

    Victor, R.A.; Farris, P.J.; Maston, V.

    1996-12-31

    The increased costs of transportation and distribution are leading many commercial and industrial firms to consider the on-site generation for energy and other commodities used in their facilities. This trend has been accelerated by the development of compact, efficient processes for converting basic raw materials into finished services at the distributed sites. Distributed generation with the PC25{trademark} fuel cell power plant is providing a new cost effective technology to meet building electric and thermal needs. Small compact on-site separator systems are providing nitrogen and oxygen to many industrial users of these gases. The adaptation of the fuel processing section of the PC25 power plant for on-site hydrogen generation at industrial sites extends distributed generation benefits to the users of industrial hydrogen.

  17. Electrical power systems for distributed generation

    SciTech Connect

    Robertson, T.A.; Huval, S.J.

    1996-12-31

    {open_quotes}Distributed Generation{close_quotes} has become the {open_quotes}buzz{close_quotes} word of an electric utility industry facing deregulation. Many industrial facilities utilize equipment in distributed installations to serve the needs of a thermal host through the capture of exhaust energy in a heat recovery steam generator. The electrical power generated is then sold as a {open_quotes}side benefit{close_quotes} to the cost-effective supply of high quality thermal energy. Distributed generation is desirable for many different reasons, each with unique characteristics of the product. Many years of experience in the distributed generation market has helped Stewart & Stevenson to define a range of product features that are crucial to most any application. The following paper will highlight a few of these applications. The paper will also examine the range of products currently available and in development. Finally, we will survey the additional services offered by Stewart & Stevenson to meet the needs of a rapidly changing power generation industry.

  18. A cellular automaton nanoflare model of coronal loops

    NASA Astrophysics Data System (ADS)

    Lopez Fuentes, Marcelo; Klimchuk, James

    In Lopez-Fuentes, Klimchuk and Mandrini (2007) we found that the evolution of soft X-ray loops can be separated into three main phases that suggest the development, maintainance, and decay of a self-organized system. Here, we present a cellular automaton model that reproduces the main features of the observed evolution. The model is based on the idea that loops are made of multiple unresolved strands which have footpoints that are displaced by random photospheric motions (Parker 1988). In this scenario, there is a continuous increase of the magnetic stress between neighboring strands until a critical stress is reached and the accumulated energy is suddenly released by reconnection. Each of these reconnection "events" is associated with a nanoflare. Using the EBTEL hydrodynamic code (Klimchuk, Patsourakos and Cargill 2008) to model the plasma response we construct synthetic light curves that we compare with the observations. We also study how the properties of the light curves scale with the different parameters of the model. Finally, we discuss how the present model can be used to explain loop observations in different wavelengths.

  19. Distributed Coordination of Energy Storage with Distributed Generators

    SciTech Connect

    Yang, Tao; Wu, Di; Stoorvogel, Antonie A.; Stoustrup, Jakob

    2016-07-18

    With a growing emphasis on energy efficiency and system flexibility, a great effort has been made recently in developing distributed energy resources (DER), including distributed generators and energy storage systems. This paper first formulates an optimal coordination problem considering constraints at both system and device levels, including power balance constraint, generator output limits, storage energy and power capacity and charging/discharging efficiencies. An algorithm is then proposed to dynamically and automatically coordinate DERs in a distributed manner. With the proposed algorithm, the agent at each DER only maintains a local incremental cost and updates it through information exchange with a few neighbors, without relying on any central decision maker. Simulation results are used to illustrate and validate the proposed algorithm.

  20. Hydrodynamic Simulation of a Nanoflare-heated Multistrand Solar Atmospheric Loop

    NASA Astrophysics Data System (ADS)

    Sarkar, Aveek; Walsh, Robert W.

    2008-08-01

    There is a growing body of evidence that the plasma loops seen with current instrumentation (SOHO, TRACE, and Hinode) may consist of many subresolution elements or strands. Thus, the overall plasma evolution we observe in these features could be the cumulative result of numerous individual strands undergoing sporadic heating. This paper presents a short (109 cm ≡ 10 Mm ) "global loop" as 125 individual strands, where each strand is modeled independently by a one-dimensional hydrodynamic simulation. The energy-release mechanism across the strands consists of localized, discrete heating events (nanoflares). The strands are "coupled" together through the frequency distribution of the total energy input to the loop, which follows a power-law distribution with index α. The location and lifetime of each energy event is random. Although a typical strand can go through a series of well-defined heating/cooling cycles, when the strands are combined, the overall quasi-static emission-measure-weighted thermal profile for the global loop reproduces a hot apex/cool base structure. Localized cool plasma blobs are seen to travel along individual strands, which could cause the loop to "disappear" from coronal emission and to appear in transition or chromospheric emission. As α increases (from 0 to 2.29 to 3.29), more weight is given to the smallest heating episodes. Consequently, the overall global loop apex temperature increases, while the variation of the temperature around that value decreases. Any further increase in α saturates the loop apex temperature variations at the current simulation resolution. The effect of increasing the number of strands and the loop length, as well as the implications of these results for possible future observing campaigns for TRACE and Hinode, are discussed.

  1. Next generation distributed computing for cancer research.

    PubMed

    Agarwal, Pankaj; Owzar, Kouros

    2014-01-01

    Advances in next generation sequencing (NGS) and mass spectrometry (MS) technologies have provided many new opportunities and angles for extending the scope of translational cancer research while creating tremendous challenges in data management and analysis. The resulting informatics challenge is invariably not amenable to the use of traditional computing models. Recent advances in scalable computing and associated infrastructure, particularly distributed computing for Big Data, can provide solutions for addressing these challenges. In this review, the next generation of distributed computing technologies that can address these informatics problems is described from the perspective of three key components of a computational platform, namely computing, data storage and management, and networking. A broad overview of scalable computing is provided to set the context for a detailed description of Hadoop, a technology that is being rapidly adopted for large-scale distributed computing. A proof-of-concept Hadoop cluster, set up for performance benchmarking of NGS read alignment, is described as an example of how to work with Hadoop. Finally, Hadoop is compared with a number of other current technologies for distributed computing.

  2. Next Generation Distributed Computing for Cancer Research

    PubMed Central

    Agarwal, Pankaj; Owzar, Kouros

    2014-01-01

    Advances in next generation sequencing (NGS) and mass spectrometry (MS) technologies have provided many new opportunities and angles for extending the scope of translational cancer research while creating tremendous challenges in data management and analysis. The resulting informatics challenge is invariably not amenable to the use of traditional computing models. Recent advances in scalable computing and associated infrastructure, particularly distributed computing for Big Data, can provide solutions for addressing these challenges. In this review, the next generation of distributed computing technologies that can address these informatics problems is described from the perspective of three key components of a computational platform, namely computing, data storage and management, and networking. A broad overview of scalable computing is provided to set the context for a detailed description of Hadoop, a technology that is being rapidly adopted for large-scale distributed computing. A proof-of-concept Hadoop cluster, set up for performance benchmarking of NGS read alignment, is described as an example of how to work with Hadoop. Finally, Hadoop is compared with a number of other current technologies for distributed computing. PMID:25983539

  3. Pseudoabsence Generation Strategies for Species Distribution Models

    PubMed Central

    Hanberry, Brice B.; He, Hong S.; Palik, Brian J.

    2012-01-01

    Background Species distribution models require selection of species, study extent and spatial unit, statistical methods, variables, and assessment metrics. If absence data are not available, another important consideration is pseudoabsence generation. Different strategies for pseudoabsence generation can produce varying spatial representation of species. Methodology We considered model outcomes from four different strategies for generating pseudoabsences. We generating pseudoabsences randomly by 1) selection from the entire study extent, 2) a two-step process of selection first from the entire study extent, followed by selection for pseudoabsences from areas with predicted probability <25%, 3) selection from plots surveyed without detection of species presence, 4) a two-step process of selection first for pseudoabsences from plots surveyed without detection of species presence, followed by selection for pseudoabsences from the areas with predicted probability <25%. We used Random Forests as our statistical method and sixteen predictor variables to model tree species with at least 150 records from Forest Inventory and Analysis surveys in the Laurentian Mixed Forest province of Minnesota. Conclusions Pseudoabsence generation strategy completely affected the area predicted as present for species distribution models and may be one of the most influential determinants of models. All the pseudoabsence strategies produced mean AUC values of at least 0.87. More importantly than accuracy metrics, the two-step strategies over-predicted species presence, due to too much environmental distance between the pseudoabsences and recorded presences, whereas models based on random pseudoabsences under-predicted species presence, due to too little environmental distance between the pseudoabsences and recorded presences. Models using pseudoabsences from surveyed plots produced a balance between areas with high and low predicted probabilities and the strongest relationship between

  4. Next Generation Multimedia Distributed Data Base Systems

    NASA Technical Reports Server (NTRS)

    Pendleton, Stuart E.

    1997-01-01

    The paradigm of client/server computing is changing. The model of a server running a monolithic application and supporting clients at the desktop is giving way to a different model that blurs the line between client and server. We are on the verge of plunging into the next generation of computing technology--distributed object-oriented computing. This is not only a change in requirements but a change in opportunities, and requires a new way of thinking for Information System (IS) developers. The information system demands caused by global competition are requiring even more access to decision making tools. Simply, object-oriented technology has been developed to supersede the current design process of information systems which is not capable of handling next generation multimedia.

  5. Nonlinear harmonic generation in distributed optical klystrons

    SciTech Connect

    H.P. Freund; George R. Neil

    2001-12-01

    A distributed optical klystron has the potential for dramatically shortening the total interaction length in high-gain free-electron lasers (INP 77-59, Novosibirsk, 1977; Nucl. Instr. and Meth A 304 (1991) 463) in comparison to a single-wiggler-segment configuration. This shortening can be even more dramatic if a nonlinear harmonic generation mechanism is used to reach the desired wavelength. An example operating at a 4.5{angstrom} fundamental and a 1.5{angstrom} harmonic is discussed.

  6. Distributed Generation with Heat Recovery and Storage

    SciTech Connect

    Siddiqui, Afzal; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

    2005-07-29

    Electricity generated by distributed energy resources (DER) located close to end-use loads has the potential to meet consumer requirements more efficiently than the existing centralized grid. Installation of DER allows consumers to circumvent the costs associated with transmission congestion and other non-energy costs of electricity delivery and potentially to take advantage of market opportunities to purchase energy when attractive. On-site thermal power generation is typically less efficient than central station generation, but by avoiding non-fuel costs of grid power and utilizing combined heat and power (CHP) applications, i.e., recovering heat from small-scale on-site generation to displace fuel purchases, then DER can become attractive to a strictly cost-minimizing consumer. In previous efforts, the decisions facing typical commercial consumers have been addressed using a mixed-integer linear programme, the DER Customer Adoption Model(DER-CAM). Given the site s energy loads, utility tariff structure, and information (both technical and financial) on candidate DER technologies, DER-CAM minimizes the overall energy cost for a test year by selecting the units to install and determining their hourly operating schedules. In this paper, the capabilities of DER-CAM are enhanced by the inclusion of the option to store recovered low-grade heat. By being able to keep an inventory of heat for use in subsequent periods, sites are able to lower costs even further by reducing off-peak generation and relying on storage. This and other effects of storages are demonstrated by analysis of five typical commercial buildings in San Francisco, California, and an estimate of the cost per unit capacity of heat storage is calculated.

  7. Integrated, Automated Distributed Generation Technologies Demonstration

    SciTech Connect

    Jensen, Kevin

    2014-09-01

    The purpose of the NETL Project was to develop a diverse combination of distributed renewable generation technologies and controls and demonstrate how the renewable generation could help manage substation peak demand at the ATK Promontory plant site. The Promontory plant site is located in the northwestern Utah desert approximately 25 miles west of Brigham City, Utah. The plant encompasses 20,000 acres and has over 500 buildings. The ATK Promontory plant primarily manufactures solid propellant rocket motors for both commercial and government launch systems. The original project objectives focused on distributed generation; a 100 kW (kilowatt) wind turbine, a 100 kW new technology waste heat generation unit, a 500 kW energy storage system, and an intelligent system-wide automation system to monitor and control the renewable energy devices then release the stored energy during the peak demand time. The original goal was to reduce peak demand from the electrical utility company, Rocky Mountain Power (RMP), by 3.4%. For a period of time we also sought to integrate our energy storage requirements with a flywheel storage system (500 kW) proposed for the Promontory/RMP Substation. Ultimately the flywheel storage system could not meet our project timetable, so the storage requirement was switched to a battery storage system (300 kW.) A secondary objective was to design/install a bi-directional customer/utility gateway application for real-time visibility and communications between RMP, and ATK. This objective was not achieved because of technical issues with RMP, ATK Information Technology Department’s stringent requirements based on being a rocket motor manufacturing facility, and budget constraints. Of the original objectives, the following were achieved: • Installation of a 100 kW wind turbine. • Installation of a 300 kW battery storage system. • Integrated control system installed to offset electrical demand by releasing stored energy from renewable sources

  8. Intelligent layered nanoflare: ``lab-on-a-nanoparticle'' for multiple DNA logic gate operations and efficient intracellular delivery

    NASA Astrophysics Data System (ADS)

    Yang, Bin; Zhang, Xiao-Bing; Kang, Li-Ping; Huang, Zhi-Mei; Shen, Guo-Li; Yu, Ru-Qin; Tan, Weihong

    2014-07-01

    DNA strand displacement cascades have been engineered to construct various fascinating DNA circuits. However, biological applications are limited by the insufficient cellular internalization of naked DNA structures, as well as the separated multicomponent feature. In this work, these problems are addressed by the development of a novel DNA nanodevice, termed intelligent layered nanoflare, which integrates DNA computing at the nanoscale, via the self-assembly of DNA flares on a single gold nanoparticle. As a ``lab-on-a-nanoparticle'', the intelligent layered nanoflare could be engineered to perform a variety of Boolean logic gate operations, including three basic logic gates, one three-input AND gate, and two complex logic operations, in a digital non-leaky way. In addition, the layered nanoflare can serve as a programmable strategy to sequentially tune the size of nanoparticles, as well as a new fingerprint spectrum technique for intelligent multiplex biosensing. More importantly, the nanoflare developed here can also act as a single entity for intracellular DNA logic gate delivery, without the need of commercial transfection agents or other auxiliary carriers. By incorporating DNA circuits on nanoparticles, the presented layered nanoflare will broaden the applications of DNA circuits in biological systems, and facilitate the development of DNA nanotechnology.DNA strand displacement cascades have been engineered to construct various fascinating DNA circuits. However, biological applications are limited by the insufficient cellular internalization of naked DNA structures, as well as the separated multicomponent feature. In this work, these problems are addressed by the development of a novel DNA nanodevice, termed intelligent layered nanoflare, which integrates DNA computing at the nanoscale, via the self-assembly of DNA flares on a single gold nanoparticle. As a ``lab-on-a-nanoparticle'', the intelligent layered nanoflare could be engineered to perform a variety of

  9. Flares on A-type Stars: Evidence for Heating of Solar Corona by Nanoflares?

    NASA Astrophysics Data System (ADS)

    Švanda, Michal; Karlický, Marian

    2016-11-01

    We analyzed the occurrence rates of flares on stars of spectral types K, G, F, and A, observed by Kepler. We found that the histogram of occurrence frequencies of stellar flares is systematically shifted toward a high-energy tail for A-type stars compared to stars of cooler spectral types. We extrapolated the fitted power laws toward flares with smaller energies (nanoflares) and made estimates for total energy flux to stellar atmospheres by flares. We found that, for A-type stars, the total energy flux density was at least four-times smaller than for G stars. We speculate that this deficit in energy supply may explain the lack of hot coronae on A-type stars. Our results indicate the importance of nanoflares for heating and formation of the solar corona.

  10. Distributed Generation with Heat Recovery and Storage

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

    2006-06-16

    Electricity produced by distributed energy resources (DER)located close to end-use loads has the potential to meet consumerrequirements more efficiently than the existing centralized grid.Installation of DER allows consumers to circumvent the costs associatedwith transmission congestion and other non-energy costs of electricitydelivery and potentially to take advantage of market opportunities topurchase energy when attractive. On-site, single-cycle thermal powergeneration is typically less efficient than central station generation,but by avoiding non-fuel costs of grid power and by utilizing combinedheat and power (CHP) applications, i.e., recovering heat from small-scaleon-site thermal generation to displace fuel purchases, DER can becomeattractive to a strictly cost-minimizing consumer. In previous efforts,the decisions facing typical commercial consumers have been addressedusing a mixed-integer linear program, the DER Customer Adoption Model(DER-CAM). Given the site s energy loads, utility tariff structure, andinformation (both technical and financial) on candidate DER technologies,DER-CAM minimizes the overall energy cost for a test year by selectingthe units to install and determining their hourly operating schedules. Inthis paper, the capabilities of DER-CAM are enhanced by the inclusion ofthe option to store recovered low-grade heat. By being able to keep aninventory of heat for use in subsequent periods, sites are able to lowercosts even further by reducing lucrative peak-shaving generation whilerelying on storage to meet heat loads. This and other effects of storageare demonstrated by analysis of five typical commercial buildings in SanFrancisco, California, USA, and an estimate of the cost per unit capacityof heat storage is calculated.

  11. The Transition Region Response to a Coronal Nanoflare: Forward Modeling and Observations in SDO/AIA

    NASA Astrophysics Data System (ADS)

    Viall, Nicholeen; Klimchuk, James A.

    2016-05-01

    The corona and transition region (TR) are fundamentally coupled through the processes of thermal conduction and mass exchange. Yet the temperature-dependent emissions from the two locations behave quite differently in the aftermath of an impulsive heating event such as a coronal nanoflare. In this presentation, we use results from the EBTEL hydrodynamics code to demonstrate that after a coronal nanoflare, the TR is multithermal and the emission at all temperatures responds in unison. This is in contrast to the coronal plasma, which cools sequentially, emitting first at higher temperatures and then at lower temperatures. We apply the time lag technique of Viall & Klimchuk (2012) to the simulated Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory emission and show that coronal plasma light curves exhibit post-nanoflare cooling time lags, while TR light curves show time lags of zero, as observed. We further demonstrate that time lags of zero, regardless of physical cause, do not indicate a lack of variability. Rather, strong variability must be present, and it must occur in unison in the different channels. Lastly, we show that the 'coronal' channels in AIA can be dominated by bright TR emission. When defined in a physically meaningful way, the TR reaches a temperature of roughly 60% the peak temperature in a flux tube. The TR resulting from impulsive heating can extend to 3 MK and higher, well within the range of the 'coronal' AIA channels.

  12. Distributed Generation of Electricity and its Environmental Impacts

    EPA Pesticide Factsheets

    When connected to the electric utility’s lower voltage distribution lines, distributed generation can help support delivery of clean, reliable power to additional customers and reduce electricity losses along transmission and distribution lines.

  13. Nanoflare Evidence from Analysis of the X-Ray Variability of an Active Region Observed with Hinode/XRT

    NASA Technical Reports Server (NTRS)

    Terzo, S.; Reale, F.; Kano, R.; Tsuneta, S.; Klimchuk, J. A.

    2011-01-01

    The investigation of the heating mechanisms of the confined coronal plasma is still under intense debate. It is widely believed that the energy source for coronal heating is the magnetic energy stored in the solar corona. An unsolved problem is how this magnetic energy is converted into thermal energy of the confined coronal plasma. As Parker proposed in 1988 rapid pulses called nanoflares are among the best candidate mechanisms of magnetic energy release. Nowadays a challenging problem is to obtain evidence that such nanoflares are really at work. If small energy discharges (nanoflares) contribute in some way to coronal heating, they could be too small and frequent to be resolved as independent events. In this case, we would need to search for indirect evidence. The idea of this work is that, if the solar corona emission is sustained by repeated nanoflares, locally the X-ray emission may not be entirely constant but may show variations around the mean intensity. So the nanoflares may leave their signature on the light curves. Many authors (Shimizu & Tsuneta 1997; Vekstein & Katsukawa 2000; Katsukawa & Tsuneta 2001; Katsukawa 2003; Sakamoto et al. 2008) pointed out that a detailed analysis of intensity fluctuations of the coronal X-ray emission could give us information on these smallest flares. Following this hint we use this approach for the first time on Hinode data, searching, with statistical analysis, for small but systematic variability in noisy background light curves and their link to coronal heating models.

  14. SMALL TURBOGENERATOR TECHNOLOGY FOR DISTRIBUTED GENERATION

    SciTech Connect

    Ali, Sy; Moritz, Bob

    2001-09-01

    in grid support. The machine is consistent with 21st century power generation objectives. It will be more efficient than a microturbine and also more cost effective because it does not require an expensive recuperator. It will produce ultra-low emissions because it has a low combustor delivery temperature. It will also avoid producing hazardous waste because it requires no lube system. These qualities are obtained by combining, and in some instances extending, the best of available technologies rather than breaking wholly new ground. Limited ''barrier technology'' rig tests of bearing systems and alternator configuration are proposed to support the extension of technology. Low combustion temperature also has merit in handling alternative fuels with minimum emissions and minimum materials degradation. Program continuation is proposed that will simultaneously provide technology support to a SECA fuel cell hybrid system and a distributed generation turbogenerator. This technology program will be led by a Rolls-Royce team based in Indianapolis with access to extensive small turbogenerator experience gathered in DOE (and other) programs by Allison Mobile Power Systems. It is intended that subsequent production will be in the U.S., but the products may have substantial export potential.

  15. The Transition Region Response to a Coronal Nanoflare: Forward Modeling and Observations in SDO/AIA

    NASA Technical Reports Server (NTRS)

    Viall-Kepko, Nicholeen M.; Klimchuk, James A.

    2015-01-01

    The corona and transition region (TR) are fundamentally coupled through the processes of thermal conduction and mass exchange. It is not possible to understand one without the other. Yet the temperature-dependent emissions from the two locations behave quite differently in the aftermath of an impulsive heating event such as a coronal nanoflare. Whereas the corona cools sequentially, emitting first at higher temperatures and then at lower temperatures, the TR is multithermal and the emission at all temperatures responds in unison. We have previously applied the automated time lag technique of Viall & Klimchuk to disk observations of an active region (AR) made by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. Lines of sight passing through coronal plasma show clear evidence for post-nanoflare cooling, while lines of sight intersecting the TR footpoints of coronal strands show zero time lag. In this paper, we use the EBTEL hydrodynamics code to demonstrate that this is precisely the expected behavior when the corona is heated by nanoflares. We also apply the time lag technique for the first time to off-limb observations of an AR. Since TR emission is not present above the limb, the occurrence of zero time lags is greatly diminished, supporting the conclusion that zero time lags measured on the disk are due to TR plasma. Lastly, we show that the "coronal" channels in AIA can be dominated by bright TR emission. When defined in a physically meaningful way, the TR reaches a temperature of roughly 60% the peak temperature in a flux tube. The TR resulting from impulsive heating can extend to 3 MK and higher, well within the range of the "coronal" AIA channels.

  16. The Transition Region Response to a Coronal Nanoflare: Forward Modeling and Observations in SDO/AIA

    NASA Astrophysics Data System (ADS)

    Viall, Nicholeen M.; Klimchuk, James A.

    2015-01-01

    The corona and transition region (TR) are fundamentally coupled through the processes of thermal conduction and mass exchange. It is not possible to understand one without the other. Yet the temperature-dependent emissions from the two locations behave quite differently in the aftermath of an impulsive heating event such as a coronal nanoflare. Whereas the corona cools sequentially, emitting first at higher temperatures and then at lower temperatures, the TR is multithermal and the emission at all temperatures responds in unison. We have previously applied the automated time lag technique of Viall & Klimchuk to disk observations of an active region (AR) made by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. Lines of sight passing through coronal plasma show clear evidence for post-nanoflare cooling, while lines of sight intersecting the TR footpoints of coronal strands show zero time lag. In this paper, we use the EBTEL hydrodynamics code to demonstrate that this is precisely the expected behavior when the corona is heated by nanoflares. We also apply the time lag technique for the first time to off-limb observations of an AR. Since TR emission is not present above the limb, the occurrence of zero time lags is greatly diminished, supporting the conclusion that zero time lags measured on the disk are due to TR plasma. Lastly, we show that the ''coronal'' channels in AIA can be dominated by bright TR emission. When defined in a physically meaningful way, the TR reaches a temperature of roughly 60% the peak temperature in a flux tube. The TR resulting from impulsive heating can extend to 3 MK and higher, well within the range of the ''coronal'' AIA channels.

  17. THE TRANSITION REGION RESPONSE TO A CORONAL NANOFLARE: FORWARD MODELING AND OBSERVATIONS IN SDO/AIA

    SciTech Connect

    Viall, Nicholeen M.; Klimchuk, James A.

    2015-01-20

    The corona and transition region (TR) are fundamentally coupled through the processes of thermal conduction and mass exchange. It is not possible to understand one without the other. Yet the temperature-dependent emissions from the two locations behave quite differently in the aftermath of an impulsive heating event such as a coronal nanoflare. Whereas the corona cools sequentially, emitting first at higher temperatures and then at lower temperatures, the TR is multithermal and the emission at all temperatures responds in unison. We have previously applied the automated time lag technique of Viall and Klimchuk to disk observations of an active region (AR) made by the Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory. Lines of sight passing through coronal plasma show clear evidence for post-nanoflare cooling, while lines of sight intersecting the TR footpoints of coronal strands show zero time lag. In this paper, we use the EBTEL hydrodynamics code to demonstrate that this is precisely the expected behavior when the corona is heated by nanoflares. We also apply the time lag technique for the first time to off-limb observations of an AR. Since TR emission is not present above the limb, the occurrence of zero time lags is greatly diminished, supporting the conclusion that zero time lags measured on the disk are due to TR plasma. Lastly, we show that the ''coronal'' channels in AIA can be dominated by bright TR emission. When defined in a physically meaningful way, the TR reaches a temperature of roughly 60% the peak temperature in a flux tube. The TR resulting from impulsive heating can extend to 3 MK and higher, well within the range of the ''coronal'' AIA channels.

  18. Distributed Coordination for Optimal Energy Generation and Distribution in Cyber-Physical Energy Networks.

    PubMed

    Ahn, Hyo-Sung; Kim, Byeong-Yeon; Lim, Young-Hun; Lee, Byung-Hun; Oh, Kwang-Kyo

    2017-02-23

    This paper proposes three coordination laws for optimal energy generation and distribution in energy network, which is composed of physical flow layer and cyber communication layer. The physical energy flows through the physical layer; but all the energies are coordinated to generate and flow by distributed coordination algorithms on the basis of communication information. First, distributed energy generation and energy distribution laws are proposed in a decoupled manner without considering the interactive characteristics between the energy generation and energy distribution. Second, a joint coordination law to treat the energy generation and energy distribution in a coupled manner taking account of the interactive characteristics is designed. Third, to handle over- or less-energy generation cases, an energy distribution law for networks with batteries is designed. The coordination laws proposed in this paper are fully distributed in the sense that they are decided optimally only using relative information among neighboring nodes. Through numerical simulations, the validity of the proposed distributed coordination laws is illustrated.

  19. Nanoflares and MHD turbulence in coronal loops: a hybrid shell model.

    PubMed

    Nigro, Giuseppina; Malara, Francesco; Carbone, Vincenzo; Veltri, Pierluigi

    2004-05-14

    A model to describe injection, due to footpoint motions, storage, and dissipation of MHD turbulence in coronal loops, is presented. The model is based on the use of the shell technique in the wave vector space applied to the set of reduced MHD equations. Numerical simulation showed that the energy injected is efficiently stored in the loop where a significant level of magnetic and velocity fluctuations is obtained. Nonlinear interactions among these fluctuations give rise to an energy cascade towards smaller scales where energy is dissipated in an intermittent fashion. The statistical analysis performed on the intermittent dissipative events compares well with all observed properties of nanoflare emission statistics.

  20. Operation of Distributed Generation Under Stochastic Prices

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris

    2005-11-30

    We model the operating decisions of a commercial enterprisethatneeds to satisfy its periodic electricity demand with either on-sitedistributed generation (DG) or purchases from the wholesale market. Whilethe former option involves electricity generation at relatively high andpossibly stochastic costs from a set of capacity-constrained DGtechnologies, the latter implies unlimited open-market transactions atstochastic prices. A stochastic dynamic programme (SDP) is used to solvethe resulting optimisation problem. By solving the SDP with and withoutthe availability of DG units, the implied option values of the DG unitsare obtained.

  1. Distributed Generation to Support Development-Focused Climate Action

    SciTech Connect

    Cox, Sadie; Gagnon, Pieter; Stout, Sherry; Zinaman, Owen; Watson, Andrea; Hotchkiss, Eliza

    2016-09-01

    This paper explores the role of distributed generation, with a high renewable energy contribution, in supporting low emission climate-resilient development. The paper presents potential impacts on development (via energy access), greenhouse gas emission mitigation, and climate resilience directly associated with distributed generation, as well as specific actions that may enhance or increase the likelihood of climate and development benefits. This paper also seeks to provide practical and timely insights to support distributed generation policymaking and planning within the context of common climate and development goals as the distributed generation landscape rapidly evolves globally. Country-specific distributed generation policy and program examples, as well as analytical tools that can inform efforts internationally, are also highlighted throughout the paper.

  2. IRIS diagnostics of non-thermal particles in coronal loops heated by nanoflares

    NASA Astrophysics Data System (ADS)

    Testa, P.; De Pontieu, B.; Allred, J. C.; Carlsson, M.; Reale, F.; Daw, A. N.

    2014-12-01

    The variability of emission of the "moss", i.e., the upper transition region (TR) layer of high pressure loops in active regions, provides stringent constraints on the characteristics of heating events. We will discuss the new coronal heating diagnostics provided by the Interface Region Imaging Spectrograph (IRIS) together with SDO/AIA. IRIS provides imaging and spectral observations of the solar chromosphere and transition region, at high spatial (0.166 arcsec/pix) and temporal (down to ~1s) resolution at FUV and NUV wavelengths. We discuss how simultaneous IRIS and AIA observations, together with loop modeling (with the RADYN code) including chromosphere, transition region and corona, allow us to study impulsive heating events (nanoflares) and the energy transport mechanism between the corona and the lower atmospheric layers (thermal conduction vs. beams of non-thermal particles). We will show how the modeling of rapid moss brightenings provides diagnostics for the presence and properties of non-thermal particles in nanoflares, which are below the detectability threshold of hard X-ray observations.

  3. Local control of reactive power by distributed photovoltaic generators

    SciTech Connect

    Chertkov, Michael; Turitsyn, Konstantin; Sulc, Petr; Backhaus, Scott

    2010-01-01

    High penetration levels of distributed photovoltaic (PV) generation on an electrical distribution circuit may severely degrade power quality due to voltage sags and swells caused by rapidly varying PV generation during cloud transients coupled with the slow response of existing utility compensation and regulation equipment. Although not permitted under current standards for interconnection of distributed generation, fast-reacting, VAR-capable PV inverters may provide the necessary reactive power injection or consumption to maintain voltage regulation under difficult transient conditions. As side benefit, the control of reactive power injection at each PV inverter provides an opportunity and a new tool for distribution utilities to optimize the performance of distribution circuits, e.g. by minimizing thermal losses. We suggest a local control scheme that dispatches reactive power from each PV inverter based on local instantaneous measurements of the real and reactive components of the consumed power and the real power generated by the PVs. Using one adjustable parameter per circuit, we balance the requirements on power quality and desire to minimize thermal losses. Numerical analysis of two exemplary systems, with comparable total PV generation albeit a different spatial distribution, show how to adjust the optimization parameter depending on the goal. Overall, this local scheme shows excellent performance; it's capable of guaranteeing acceptable power quality and achieving significant saving in thermal losses in various situations even when the renewable generation in excess of the circuit own load, i.e. feeding power back to the higher-level system.

  4. Distributed Pedagogical Leadership and Generative Dialogue in Educational Nodes

    ERIC Educational Resources Information Center

    Jappinen, Aini-Kristiina; Sarja, Anneli

    2012-01-01

    The article presents practices of distributed pedagogical leadership and generative dialogue as a tool with which management and personnel can better operate in the increasingly turbulent world of education. Distributed pedagogical leadership includes common characteristics of a professional learning community when the educational actors…

  5. Design Flexibility for Uncertain Distributed Generation from Photovoltaics

    SciTech Connect

    Palmintier, Bryan; Krishnamurthy, Dheepak; Wu, Hongyu

    2016-12-12

    Uncertainty in the future adoption patterns for distributed energy resources (DERs) introduces a challenge for electric distribution system planning. This paper explores the potential for flexibility in design - also known as real options - to identify design solutions that may never emerge when future DER patterns are treated as deterministic. A test case for storage system design with uncertain distributed generation for solar photovoltaics (DGPV) demonstrates this approach and is used to study sensitivities to a range of techno-economic assumptions.

  6. Gendist: An R Package for Generated Probability Distribution Models

    PubMed Central

    Abu Bakar, Shaiful Anuar; Nadarajah, Saralees; ABSL Kamarul Adzhar, Zahrul Azmir; Mohamed, Ibrahim

    2016-01-01

    In this paper, we introduce the R package gendist that computes the probability density function, the cumulative distribution function, the quantile function and generates random values for several generated probability distribution models including the mixture model, the composite model, the folded model, the skewed symmetric model and the arc tan model. These models are extensively used in the literature and the R functions provided here are flexible enough to accommodate various univariate distributions found in other R packages. We also show its applications in graphing, estimation, simulation and risk measurements. PMID:27272043

  7. Gendist: An R Package for Generated Probability Distribution Models.

    PubMed

    Abu Bakar, Shaiful Anuar; Nadarajah, Saralees; Absl Kamarul Adzhar, Zahrul Azmir; Mohamed, Ibrahim

    2016-01-01

    In this paper, we introduce the R package gendist that computes the probability density function, the cumulative distribution function, the quantile function and generates random values for several generated probability distribution models including the mixture model, the composite model, the folded model, the skewed symmetric model and the arc tan model. These models are extensively used in the literature and the R functions provided here are flexible enough to accommodate various univariate distributions found in other R packages. We also show its applications in graphing, estimation, simulation and risk measurements.

  8. Polarization-multiplexed plasmonic phase generation with distributed nanoslits.

    PubMed

    Lee, Seung-Yeol; Kim, Kyuho; Lee, Gun-Yeal; Lee, Byoungho

    2015-06-15

    Methods for multiplexing surface plasmon polaritons (SPPs) have been attracting much attention due to their potentials for plasmonic integrated systems, plasmonic holography, and optical tweezing. Here, using closely-distanced distributed nanoslits, we propose a method for generating polarization-multiplexed SPP phase profiles which can be applied for implementing general SPP phase distributions. Two independent types of SPP phase generation mechanisms - polarization-independent and polarization-reversible ones - are combined to generate fully arbitrary phase profiles for each optical handedness. As a simple verification of the proposed scheme, we experimentally demonstrate that the location of plasmonic focus can be arbitrary designed, and switched by the change of optical handedness.

  9. Current distribution and nonuniformity effects in MHD disk generators

    NASA Astrophysics Data System (ADS)

    Roseman, D. F.

    1982-08-01

    Current distribution and nonuniformity effects in combustion driven MHD disk generators were studied. The importance of these phenomena to baseload power generation was investigated. The peg wall construction allowed current and voltage distributions to be measured. The channel was operated with plasma temperatures up to 2750 K and magnetic field strengths up to 5.5 Tesla. The magnitudes of the currents and voltages were reduced by significant loss mechanisms, primarily electrode losses and current leakage through the wall caused by potassium seed penetration of the castable ceramic between the pegs. A simple circuit model accounting for these losses was developed to be compared with analytical calculations. Under normal uniform electrical loading the distributions measured in the channel were uniform as expected. Nonuniform electrical loading was used to produce and measure effects on the current distribution that occur only in the presence of high magnetic fields as required for MHD power generation.

  10. Analysis of the chaotic maps generating different statistical distributions

    NASA Astrophysics Data System (ADS)

    Lawnik, M.

    2015-09-01

    The analysis of the chaotic maps, enabling the derivation of numbers from given statistical distributions was presented. The analyzed chaotic maps are in the form xk+1 = F-1(U(F(xk))), where F is the cumulative distribution function, U is the skew tent map and F-1 is the inverse function of F. The analysis was presented on the example of chaotic map with the standard normal distribution in view of his computational efficiency and accuracy. On the grounds of the conducted analysis, it should be indicated that the method not always allows to generate the values from the given distribution.

  11. Estimating probable flaw distributions in PWR steam generator tubes

    SciTech Connect

    Gorman, J.A.; Turner, A.P.L.

    1997-02-01

    This paper describes methods for estimating the number and size distributions of flaws of various types in PWR steam generator tubes. These estimates are needed when calculating the probable primary to secondary leakage through steam generator tubes under postulated accidents such as severe core accidents and steam line breaks. The paper describes methods for two types of predictions: (1) the numbers of tubes with detectable flaws of various types as a function of time, and (2) the distributions in size of these flaws. Results are provided for hypothetical severely affected, moderately affected and lightly affected units. Discussion is provided regarding uncertainties and assumptions in the data and analyses.

  12. Model-Driven Test Generation of Distributed Systems

    NASA Technical Reports Server (NTRS)

    Easwaran, Arvind; Hall, Brendan; Schweiker, Kevin

    2012-01-01

    This report describes a novel test generation technique for distributed systems. Utilizing formal models and formal verification tools, spe cifically the Symbolic Analysis Laboratory (SAL) tool-suite from SRI, we present techniques to generate concurrent test vectors for distrib uted systems. These are initially explored within an informal test validation context and later extended to achieve full MC/DC coverage of the TTEthernet protocol operating within a system-centric context.

  13. Modeling Distributed Electricity Generation in the NEMS Buildings Models

    EIA Publications

    2011-01-01

    This paper presents the modeling methodology, projected market penetration, and impact of distributed generation with respect to offsetting future electricity needs and carbon dioxide emissions in the residential and commercial buildings sector in the Annual Energy Outlook 2000 (AEO2000) reference case.

  14. Energy Storage and Distributed Energy Generation Project, Final Project Report

    SciTech Connect

    Schwank, Johannes; Mader, Jerry; Chen, Xiaoyin; Mi, Chris; Linic, Suljo; Sastry, Ann Marie; Stefanopoulou, Anna; Thompson, Levi; Varde, Keshav

    2008-03-31

    This report serves as a Final Report under the “Energy Storage and Distribution Energy Generation Project” carried out by the Transportation Energy Center (TEC) at the University of Michigan (UM). An interdisciplinary research team has been working on fundamental and applied research on: -distributed power generation and microgrids, -power electronics, and -advanced energy storage. The long-term objective of the project was to provide a framework for identifying fundamental research solutions to technology challenges of transmission and distribution, with special emphasis on distributed power generation, energy storage, control methodologies, and power electronics for microgrids, and to develop enabling technologies for novel energy storage and harvesting concepts that can be simulated, tested, and scaled up to provide relief for both underserved and overstressed portions of the Nation’s grid. TEC’s research is closely associated with Sections 5.0 and 6.0 of the DOE "Five-year Program Plan for FY2008 to FY2012 for Electric Transmission and Distribution Programs, August 2006.”

  15. Distributed photovoltaic generation in residential distribution systems: Impacts on power quality and anti-islanding

    NASA Astrophysics Data System (ADS)

    Mitra, Parag

    The past few decades have seen a consistent growth of distributed PV sources. Distributed PV, like other DG sources, can be located at or near load centers and provide benefits which traditional generation may lack. However, distribution systems were not designed to accommodate such power generation sources as these sources might lead to operational as well as power quality issues. A high penetration of distributed PV resources may lead to bi-directional power flow resulting in voltage swells, increased losses and overloading of conductors. Voltage unbalance is a concern in distribution systems and the effect of single-phase residential PV systems on voltage unbalance needs to be explored. Furthermore, the islanding of DGs presents a technical hurdle towards the seamless integration of DG sources with the electricity grid. The work done in this thesis explores two important aspects of grid inte-gration of distributed PV generation, namely, the impact on power quality and anti-islanding. A test distribution system, representing a realistic distribution feeder in Arizona is modeled to study both the aforementioned aspects. The im-pact of distributed PV on voltage profile, voltage unbalance and distribution sys-tem primary losses are studied using CYMDIST. Furthermore, a PSCAD model of the inverter with anti-island controls is developed and the efficacy of the anti-islanding techniques is studied. Based on the simulations, generalized conclusions are drawn and the problems/benefits are elucidated.

  16. Distribution of the number of generations in flux compactifications

    NASA Astrophysics Data System (ADS)

    Braun, Andreas P.; Watari, Taizan

    2014-12-01

    Flux compactification of string theory generates an ensemble with a large number of vacua, called the landscape. By using the statistics of various properties of low-energy effective theories in the string landscape, one can therefore hope to provide a scientific foundation to the notion of naturalness. This article discusses how to answer such questions of practical interest by using flux compactification of F-theory. It is found that the distribution is approximately in a factorized form given by distribution on the choice of 7-brane gauge group, that on the number of generations Ngen and that on effective coupling constants. The distribution on Ngen is approximately Gaussian for the range |Ngen|≲10 . The statistical cost of higher-rank gauge group is also discussed.

  17. Neutron monitor generated data distributions in quantum variational Monte Carlo

    NASA Astrophysics Data System (ADS)

    Kussainov, A. S.; Pya, N.

    2016-08-01

    We have assessed the potential applications of the neutron monitor hardware as random number generator for normal and uniform distributions. The data tables from the acquisition channels with no extreme changes in the signal level were chosen as the retrospective model. The stochastic component was extracted by fitting the raw data with splines and then subtracting the fit. Scaling the extracted data to zero mean and variance of one is sufficient to obtain a stable standard normal random variate. Distributions under consideration pass all available normality tests. Inverse transform sampling is suggested to use as a source of the uniform random numbers. Variational Monte Carlo method for quantum harmonic oscillator was used to test the quality of our random numbers. If the data delivery rate is of importance and the conventional one minute resolution neutron count is insufficient, we could always settle for an efficient seed generator to feed into the faster algorithmic random number generator or create a buffer.

  18. Distributed query plan generation using multiobjective genetic algorithm.

    PubMed

    Panicker, Shina; Kumar, T V Vijay

    2014-01-01

    A distributed query processing strategy, which is a key performance determinant in accessing distributed databases, aims to minimize the total query processing cost. One way to achieve this is by generating efficient distributed query plans that involve fewer sites for processing a query. In the case of distributed relational databases, the number of possible query plans increases exponentially with respect to the number of relations accessed by the query and the number of sites where these relations reside. Consequently, computing optimal distributed query plans becomes a complex problem. This distributed query plan generation (DQPG) problem has already been addressed using single objective genetic algorithm, where the objective is to minimize the total query processing cost comprising the local processing cost (LPC) and the site-to-site communication cost (CC). In this paper, this DQPG problem is formulated and solved as a biobjective optimization problem with the two objectives being minimize total LPC and minimize total CC. These objectives are simultaneously optimized using a multiobjective genetic algorithm NSGA-II. Experimental comparison of the proposed NSGA-II based DQPG algorithm with the single objective genetic algorithm shows that the former performs comparatively better and converges quickly towards optimal solutions for an observed crossover and mutation probability.

  19. Size distribution of mist generated during metal machining.

    PubMed

    Thornburg, J; Leith, D

    2000-08-01

    Mist generated by machining processes is formed by three mechanisms: impaction, centrifugal force, and evaporation/condensation. This study characterized the size distribution of soluble and mineral oil mists that resulted from these formation mechanisms. Salient parameters influencing the particle size distributions also were identified. Variables investigated included metalworking fluid and machining characteristics. The size distribution of the mist generated on a small lathe by each mechanism was measured using an Aerosizer LD. For impaction, only the mineral oil viscosity influenced the mass median diameter of the mist. No parameter affected the geometric standard deviation. High-viscosity mineral oil mist had a mass median diameter of 6.1 microns and a geometric standard deviation of 2.0. Low-viscosity mineral oil mist had a mass median diameter of 21.9 microns and a geometric standard deviation of 2.2. The mass median diameter of the mist generated by centrifugal force depended on the type of metalworking fluid, fluid flow, and rotational speed of the lathe. Mass median diameters for low-viscosity mineral oil mist ranged from 5 to 110 microns. Mass median diameters for soluble oil mist varied between 40 and 80 microns. The average geometric standard deviation was 2.4, and was not affected by any parameter. The mass median diameter and geometric standard deviation of the mist generated by evaporation/condensation varied with the type of metalworking fluid. The mineral oil mist and soluble oil mist mass median diameters were 2.1 microns and 3.2 microns, respectively. No machining or fluid parameter was important because the mist size distribution depended on the rate of condensation, coagulation processes, and the dynamics of the apparatus. Using the size distribution data from all three mechanisms, the estimated inhalable, thoracic, and respirable fractions of the total mass generated for each metalworking fluid were 60 percent, 12 percent, and 8 percent

  20. Marginal capacity costs of electricity distribution and demand for distributed generation

    SciTech Connect

    Woo, Chi-Keung, Lloyd-Zanetti, D.; Orans, R.

    1995-12-31

    Marginal costs of electricity vary by time and location. Past researchers attributed these variations to factors related to electricity generation, transmission and distribution. Past authors, however, did not fully analyze the large variations in marginal distribution capacity costs (MDCC) by area and time. Thus, the objectives of this paper are as follows: (1) to show that large MDCC variations exist within a utility`s service territory; (2) to demonstrate inter-utility variations in MDCC; and (3) to demonstrate the usefulness of these costs in determining demand for distributed generation (DG). 27 refs., 3 figs., 2 tabs.

  1. Distributed Generation Investment by a Microgrid UnderUncertainty

    SciTech Connect

    Siddiqui, Afzal; Marnay, Chris

    2006-06-16

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

  2. Distributed Generation Investment by a Microgrid under Uncertainty

    SciTech Connect

    Marnay, Chris; Siddiqui, Afzal; Marnay, Chris

    2008-08-11

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

  3. Illustration of distributed generation effects on protection system coordination

    NASA Astrophysics Data System (ADS)

    Alawami, Hussain Adnan

    Environmental concerns, market forces, and emergence of new technologies have recently resulted in restructuring electric utility from vertically integrated networks to competitive deregulated entities. Distributed generation (DG) is playing a major role in such deregulated markets. When they are installed in small amounts and small sizes, their impacts on the system may be negligible. When their penetration levels increase as well as their sizes, however, they may start affecting the system performance from more than one aspect. Power system protection needs to be re-assessed after the emergence of DG. This thesis attempts to illustrate the impact of DG on the power system protection coordination. It will study the operation of the impedance relays, fuses, reclosers and overcurrent relays when a DG is added to the distribution network. Different DG sizes, distances from the network and locations within the distribution system will be considered. Power system protection coordination is very sensitive to the DG size where it is not for the DG distance. DG location has direct impact on the operation of the protective devices especially when it is inserted in the middle point of the distribution system. Key Words, Distributed Generation, Impedance relay, fuses, reclosers, overcurrent relays, power system protection coordination.

  4. Greenhouse Gas Abatement with Distributed Generation in California's Commercial Buildings

    SciTech Connect

    Marnay, Chris; Stadler, Michael; Lipman, Tim; Lai, Judy; Cardoso, Goncalo; Megel, Olivier

    2009-09-01

    The motivation and objective of this research is to determine the role of distributed generation (DG) in greenhouse gas reductions by: (1) applying the Distributed Energy Resources Customer Adoption Model (DER-CAM); (2) using the California Commercial End-Use Survey (CEUS) database for commercial buildings; (3) selecting buildings with electric peak loads between 100 kW and 5 MW; (4) considering fuel cells, micro-turbines, internal combustion engines, gas turbines with waste heat utilization, solar thermal, and PV; (5) testing of different policy instruments, e.g. feed-in tariff or investment subsidies.

  5. Narrow-band generation in random distributed feedback fiber laser.

    PubMed

    Sugavanam, Srikanth; Tarasov, Nikita; Shu, Xuewen; Churkin, Dmitry V

    2013-07-15

    Narrow-band emission of spectral width down to ~0.05 nm line-width is achieved in the random distributed feedback fiber laser employing narrow-band fiber Bragg grating or fiber Fabry-Perot interferometer filters. The observed line-width is ~10 times less than line-width of other demonstrated up to date random distributed feedback fiber lasers. The random DFB laser with Fabry-Perot interferometer filter provides simultaneously multi-wavelength and narrow-band (within each line) generation with possibility of further wavelength tuning.

  6. Electron distribution function in a plasma generated by fission fragments

    NASA Technical Reports Server (NTRS)

    Hassan, H. A.; Deese, J. E.

    1976-01-01

    A Boltzmann equation formulation is presented for the determination of the electron distribution function in a plasma generated by fission fragments. The formulation takes into consideration ambipolar diffusion, elastic and inelastic collisions, recombination and ionization, and allows for the fact that the primary electrons are not monoenergetic. Calculations for He in a tube coated with fissionable material shows that, over a wide pressure and neutron flux range, the distribution function is non-Maxwellian, but the electrons are essentially thermal. Moreover, about a third of the energy of the primary electrons is transferred into the inelastic levels of He. This fraction of energy transfer is almost independent of pressure and neutron flux.

  7. The flow-chart loop: temperature, density, and cooling observables supporting nanoflare coronal heating models

    SciTech Connect

    Schmelz, J. T.; Pathak, S.; Dhaliwal, R. S.; Christian, G. M.; Fair, C. B.

    2014-11-10

    We have tested three controversial properties for a target loop observed with the Atmospheric Imaging Assembly: (1) overdense loops; (2) long-lifetime loops; and (3) multithermal loops. Our loop is overdense by a factor of about 10 compared to results expected from steady uniform heating models. If this were the only inconsistency, our loop could still be modeled as a single strand, but the density mismatch would imply that the heating must be impulsive. Moving on to the second observable, however, we find that the loop lifetime is at least an order of magnitude greater than the predicted cooling time. This implies that the loop cannot be composed of a single flux tube, even if the heating were dynamic, and must be multi-stranded. Finally, differential emission measure analysis shows that the cross-field temperature of the target loop is multithermal in the early and middle phases of its lifetime, but effectively isothermal before it fades from view. If these multithermal cooling results are found to be widespread, our results could resolve the original coronal loop controversy of 'isothermal' versus 'multithermal' cross-field temperatures. That is, the cross-field temperature is not always 'multithermal' nor is it always 'isothermal', but might change as the loop cools. We find that the existence and evolution of this loop is consistent with predictions of nanoflare heating.

  8. DETECTING NANOFLARE HEATING EVENTS IN SUBARCSECOND INTER-MOSS LOOPS USING Hi-C

    SciTech Connect

    Winebarger, Amy R.; Moore, Ronald; Cirtain, Jonathan; Walsh, Robert W.; De Pontieu, Bart; Title, Alan; Hansteen, Viggo; Golub, Leon; Korreck, Kelly; Weber, Mark; Kobayashi, Ken; DeForest, Craig; Kuzin, Sergey

    2013-07-01

    The High-resolution Coronal Imager (Hi-C) flew aboard a NASA sounding rocket on 2012 July 11 and captured roughly 345 s of high-spatial and temporal resolution images of the solar corona in a narrowband 193 A channel. In this paper, we analyze a set of rapidly evolving loops that appear in an inter-moss region. We select six loops that both appear in and fade out of the Hi-C images during the short flight. From the Hi-C data, we determine the size and lifetimes of the loops and characterize whether these loops appear simultaneously along their length or first appear at one footpoint before appearing at the other. Using co-aligned, co-temporal data from multiple channels of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory, we determine the temperature and density of the loops. We find the loops consist of cool ({approx}10{sup 5} K), dense ({approx}10{sup 10} cm{sup -3}) plasma. Their required thermal energy and their observed evolution suggest they result from impulsive heating similar in magnitude to nanoflares. Comparisons with advanced numerical simulations indicate that such dense, cold and short-lived loops are a natural consequence of impulsive magnetic energy release by reconnection of braided magnetic field at low heights in the solar atmosphere.

  9. MODELING SOLAR CORONAL BRIGHT-POINT OSCILLATIONS WITH MULTIPLE NANOFLARE HEATED LOOPS

    SciTech Connect

    Chandrashekhar, K; Sarkar, Aveek E-mail: aveek.sarkar@iiserkol.ac.in

    2015-09-10

    Intensity oscillations of coronal bright points (BPs) have been studied for the past several years. It has been known for a while that these BPs are closed magnetic loop-like structures. However, the initiation of such intensity oscillations is still an enigma. There have been many suggestions to explain these oscillations, but so far modeling such BPs has not been explored. Using a multithreaded nanoflare heated loop model we study the behavior of such BPs in this work. We compute typical loop lengths of BPs using potential field-line extrapolation of available data, and set this as the length of our simulated loops. We produce intensity-like observables through forward modeling and analyze the intensity time series using wavelet analysis, as was done by previous observers. The result reveals similar intensity oscillation periods reported in past observations. It is suggested these oscillations are actually shock wave propagations along the loop. We also show that if one considers different background subtractions, one can extract adiabatic standing modes from the intensity time-series data as well, both from the observed and simulated data.

  10. ANALYSIS OF DISTRIBUTION FEEDER LOSSES DUE TO ADDITION OF DISTRIBUTED PHOTOVOLTAIC GENERATORS

    SciTech Connect

    Tuffner, Francis K.; Singh, Ruchi

    2011-08-09

    Distributed generators (DG) are small scale power supplying sources owned by customers or utilities and scattered throughout the power system distribution network. Distributed generation can be both renewable and non-renewable. Addition of distributed generation is primarily to increase feeder capacity and to provide peak load reduction. However, this addition comes with several impacts on the distribution feeder. Several studies have shown that addition of DG leads to reduction of feeder loss. However, most of these studies have considered lumped load and distributed load models to analyze the effects on system losses, where the dynamic variation of load due to seasonal changes is ignored. It is very important for utilities to minimize the losses under all scenarios to decrease revenue losses, promote efficient asset utilization, and therefore, increase feeder capacity. This paper will investigate an IEEE 13-node feeder populated with photovoltaic generators on detailed residential houses with water heater, Heating Ventilation and Air conditioning (HVAC) units, lights, and other plug and convenience loads. An analysis of losses for different power system components, such as transformers, underground and overhead lines, and triplex lines, will be performed. The analysis will utilize different seasons and different solar penetration levels (15%, 30%).

  11. A Bio-Based Fuel Cell for Distributed Energy Generation

    SciTech Connect

    Anthony Terrinoni; Sean Gifford

    2008-06-30

    The technology we propose consists primarily of an improved design for increasing the energy density of a certain class of bio-fuel cell (BFC). The BFCs we consider are those which harvest electrons produced by microorganisms during their metabolism of organic substrates (e.g. glucose, acetate). We estimate that our technology will significantly enhance power production (per unit volume) of these BFCs, to the point where they could be employed as stand-alone systems for distributed energy generation.

  12. The generation of side force by distributed suction

    NASA Technical Reports Server (NTRS)

    Roberts, Leonard; Hong, John

    1993-01-01

    This report provides an approximate analysis of the generation of side force on a cylinder placed horizontal to the flow direction by the application of distributed suction on the rearward side of the cylinder. Relationships are derived between the side force coefficients and the required suction coefficients necessary to maintain attached flow on one side of the cylinder, thereby inducing circulation around the cylinder and a corresponding side force.

  13. Distributed Generation System Characteristics and Costs in the Buildings Sector

    EIA Publications

    2013-01-01

    The Energy Information Administration (EIA) works with technology experts to project the cost and performance of future residential and commercial sector photovoltaic (PV) and small wind installations rather than developing technology projections in-house. These reports have always been available by request. By providing the reports online, EIA is increasing transparency for the assumptions used for our Annual Energy Outlook buildings sector distributed generation projections.

  14. Modeling and Verification of Distributed Generation and Voltage Regulation Equipment for Unbalanced Distribution Power Systems; Annual Subcontract Report, June 2007

    SciTech Connect

    Davis, M. W.; Broadwater, R.; Hambrick, J.

    2007-07-01

    This report summarizes the development of models for distributed generation and distribution circuit voltage regulation equipment for unbalanced power systems and their verification through actual field measurements.

  15. Distributed Generation Market Demand Model (dGen): Documentation

    SciTech Connect

    Sigrin, Benjamin; Gleason, Michael; Preus, Robert; Baring-Gould, Ian; Margolis, Robert

    2016-02-01

    The Distributed Generation Market Demand model (dGen) is a geospatially rich, bottom-up, market-penetration model that simulates the potential adoption of distributed energy resources (DERs) for residential, commercial, and industrial entities in the continental United States through 2050. The National Renewable Energy Laboratory (NREL) developed dGen to analyze the key factors that will affect future market demand for distributed solar, wind, storage, and other DER technologies in the United States. The new model builds off, extends, and replaces NREL's SolarDS model (Denholm et al. 2009a), which simulates the market penetration of distributed PV only. Unlike the SolarDS model, dGen can model various DER technologies under one platform--it currently can simulate the adoption of distributed solar (the dSolar module) and distributed wind (the dWind module) and link with the ReEDS capacity expansion model (Appendix C). The underlying algorithms and datasets in dGen, which improve the representation of customer decision making as well as the spatial resolution of analyses (Figure ES-1), also are improvements over SolarDS.

  16. Fuel cycle comparison of distributed power generation technologies.

    SciTech Connect

    Elgowainy, A.; Wang, M. Q.; Energy Systems

    2008-12-08

    The fuel-cycle energy use and greenhouse gas (GHG) emissions associated with the application of fuel cells to distributed power generation were evaluated and compared with the combustion technologies of microturbines and internal combustion engines, as well as the various technologies associated with grid-electricity generation in the United States and California. The results were primarily impacted by the net electrical efficiency of the power generation technologies and the type of employed fuels. The energy use and GHG emissions associated with the electric power generation represented the majority of the total energy use of the fuel cycle and emissions for all generation pathways. Fuel cell technologies exhibited lower GHG emissions than those associated with the U.S. grid electricity and other combustion technologies. The higher-efficiency fuel cells, such as the solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC), exhibited lower energy requirements than those for combustion generators. The dependence of all natural-gas-based technologies on petroleum oil was lower than that of internal combustion engines using petroleum fuels. Most fuel cell technologies approaching or exceeding the DOE target efficiency of 40% offered significant reduction in energy use and GHG emissions.

  17. A concurrent distributed system for aircraft tactical decision generation

    NASA Technical Reports Server (NTRS)

    Mcmanus, John W.

    1990-01-01

    A research program investigating the use of AI techniques to aid in the development of a tactical decision generator (TDG) for within visual range (WVR) air combat engagements is discussed. The application of AI programming and problem-solving methods in the development and implementation of a concurrent version of the computerized logic for air-to-air warfare simulations (CLAWS) program, a second-generation TDG, is presented. Concurrent computing environments and programming approaches are discussed, and the design and performance of prototype concurrent TDG system (Cube CLAWS) are presented. It is concluded that the Cube CLAWS has provided a useful testbed to evaluate the development of a distributed blackboard system. The project has shown that the complexity of developing specialized software on a distributed, message-passing architecture such as the Hypercube is not overwhelming, and that reasonable speedups and processor efficiency can be achieved by a distributed blackboard system. The project has also highlighted some of the costs of using a distributed approach to designing a blackboard system.

  18. Optimal Solar PV Arrays Integration for Distributed Generation

    SciTech Connect

    Omitaomu, Olufemi A; Li, Xueping

    2012-01-01

    Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introduce quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.

  19. Operational maintenance data for power generation distribution and HVAC components

    SciTech Connect

    Hollis, H.D.; Hale, P.S. Jr.; Arno, R.G.; Briggs, S.J.

    1995-12-31

    This paper describes the culmination of a 24,000 man hour effort to collect operational and maintenance data on 239 power generation, power distribution and HVAC items, including gas turbine generators, diesel engine generators, switch gear assemblies, cables, boilers, piping, valves and chillers. This program was designed to determine the effects of new technology equipment, i.e., equipment installed after 1971, on availability. The central hypothesis was that this new equipment would exhibit a significant increase in availability, with corresponding decreases in required maintenance and the occurrence of failures. Information was obtained on a variety of commercial and industrial facility types (including office buildings, hospitals, water treatment facilities, prisons, utilities, manufacturing facilities, school universities and bank computer centers), with varying degrees of maintenance quality.

  20. Assessment of Distributed Generation Potential in JapaneseBuildings

    SciTech Connect

    Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun; Nishida,Masaru

    2005-05-25

    To meet growing energy demands, energy efficiency, renewable energy, and on-site generation coupled with effective utilization of exhaust heat will all be required. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems (or microgrids). This research investigates a method of choosing economically optimal DER, expanding on prior studies at the Berkeley Lab using the DER design optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM finds the optimal combination of installed equipment from available DER technologies, given prevailing utility tariffs, site electrical and thermal loads, and a menu of available equipment. It provides a global optimization, albeit idealized, that shows how the site energy loads can be served at minimum cost by selection and operation of on-site generation, heat recovery, and cooling. Five prototype Japanese commercial buildings are examined and DER-CAM applied to select the economically optimal DER system for each. The five building types are office, hospital, hotel, retail, and sports facility. Based on the optimization results, energy and emission reductions are evaluated. Furthermore, a Japan-U.S. comparison study of policy, technology, and utility tariffs relevant to DER installation is presented. Significant decreases in fuel consumption, carbon emissions, and energy costs were seen in the DER-CAM results. Savings were most noticeable in the sports facility (a very favourable CHP site), followed by the hospital, hotel, and office building.

  1. The Value of Distributed Generation under Different TariffStructures

    SciTech Connect

    Firestone, Ryan; Magnus Maribu, Karl; Marnay, Chris

    2006-05-31

    Distributed generation (DG) may play a key role in a modern energy system because it can improve energy efficiency. Reductions in the energy bill, and therefore DG attractiveness, depend on the electricity tariff structure; a system created before widespread adoption of distributed generation. Tariffs have been designed to recover costs equitably amongst customers with similar consumption patterns. Recently, electric utilities began to question the equity of this electricity pricing structure for standby service. In particular, the utilities do not feel that DG customers are paying their fair share of transmission and distribution costs - traditionally recovered through a volumetric($/kWh) mechanism - under existing tariff structures. In response, new tariff structures with higher fixed costs for DG have been implemented in New York and in California. This work analyzes the effects of different electricity tariff structures on DG adoption. First, the effects of the new standby tariffs in New York are analyzed in different regions. Next generalized tariffs are constructed, and the sensitivity to varying levels of the volumetric and the demand ($/kW, i.e. maximum rate) charge component are analyzed on New York's standard and standby tariff as well as California's standby tariff. As expected, DG profitability is reduced with standby tariffs, but often marginally. The new standby structures tend to promote smaller base load systems. The amount of time-of-day variability of volumetric pricing seems to have little effect on DG economics.

  2. Simple method of generating and distributing frequency-entangled qudits

    NASA Astrophysics Data System (ADS)

    Jin, Rui-Bo; Shimizu, Ryosuke; Fujiwara, Mikio; Takeoka, Masahiro; Wakabayashi, Ryota; Yamashita, Taro; Miki, Shigehito; Terai, Hirotaka; Gerrits, Thomas; Sasaki, Masahide

    2016-11-01

    High-dimensional, frequency-entangled photonic quantum bits (qudits for d-dimension) are promising resources for quantum information processing in an optical fiber network and can also be used to improve channel capacity and security for quantum communication. However, up to now, it is still challenging to prepare high-dimensional frequency-entangled qudits in experiments, due to technical limitations. Here we propose and experimentally implement a novel method for a simple generation of frequency-entangled qudts with d\\gt 10 without the use of any spectral filters or cavities. The generated state is distributed over 15 km in total length. This scheme combines the technique of spectral engineering of biphotons generated by spontaneous parametric down-conversion and the technique of spectrally resolved Hong-Ou-Mandel interference. Our frequency-entangled qudits will enable quantum cryptographic experiments with enhanced performances. This distribution of distinct entangled frequency modes may also be useful for improved metrology, quantum remote synchronization, as well as for fundamental test of stronger violation of local realism.

  3. Application of a nanoflare probe specific to a latency associated transcript for isolation of KHV latently infected cells

    PubMed Central

    Reed, Aimee N.; Putman, Timothy; Sullivan, Christopher; Jin, Ling

    2015-01-01

    One of the unique features of herpesvirus infection is latent infection following an initial exposure, which is characterized by viral genome persistence in a small fraction of cells within the latently infected tissue. Investigation of the mechanisms of herpesvirus latency has been very challenging in tissues with only a small fraction of cells that are latently infected. Cyprinid herpesvirus 3, also known as koi herpesvirus (KHV), is an important and deadly pathogen of koi and common carp, Cyprinus carpio. Acute infection can cause up to 100% mortality in exposed fish, and fish that survive the infection become latently infected. KHV becomes latent in a small percentage of B lymphocytes and can reactivate under stressful conditions. During latency, KHV ORF6 transcript is expressed in the latently infected B lymphocytes. In order to study KHV latent infection in cells that are only latently infected, a nanoflare probe specific to ORF6 RNA was used to separate KHV latently infected cells from total peripheral white blood cells (WBC). Using the ORF6 nanoflare probe, less than 1% of peripheral WBC was isolated from KHV latently infected koi. When this enriched population of WBC was examined by real-time PCR specific for KHV, it was estimated that about 1 to 2 copies of viral genome persists in the sorted cells. In addition, KHV ORF6 transcript was shown to be the major transcript expressed during latency by RNA-seq analysis. This study demonstrated that an RNA nanoflare probe could be used to enrich latently infected cells, which can subsequently be used to investigate the molecular mechanisms of KHV latency. PMID:26087404

  4. Stabilization of a Power System including Inverter Type Distributed Generators by the Virtual Synchronous Generator

    NASA Astrophysics Data System (ADS)

    Sakimoto, Kenichi; Miura, Yushi; Ise, Toshifumi

    The capacity of Distributed Generators (DGs) connected to grid by inverters are growing year and year. The inverters are generally controlled by PLL (Phase Locked Loop) in order to synchronize with power system frequency. Power systems will become unstable, if the capacity of inverter type DGs become larger and larger, because inverter frequency is controlled just to follow the frequency decided by other synchronous generators. There is the idea that inverters are controlled to behave like a synchronous generator. This concept is called Virtual Synchronous Generator (VSG). In this paper, a control scheme of VSG is presented, and the design method of required energy storage and the ability of grid stabilizing control by VSG is investigated by computer simulations.

  5. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2004-07-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the January to June 2004 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  6. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2004-01-04

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the July 2003 to December 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. Also, another activity included in this program focuses on the development of SOFC scale up strategies.

  7. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh; Faress Rahman

    2002-12-31

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the October 2002 to December 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The following activities have been carried out during this reporting period: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} Part-load performance analysis was conducted {lg_bullet} Primary system concept was down-selected {lg_bullet} Dynamic control model has been developed {lg_bullet} Preliminary heat exchanger designs were prepared {lg_bullet} Pressurized SOFC endurance testing was performed

  8. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    David Deangelis; Rich Depuy; Debashis Dey; Georgia Karvountzi; Nguyen Minh; Max Peter; Faress Rahman; Pavel Sokolov; Deliang Yang

    2004-09-30

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC (HPGS) during the April to October 2004 reporting period in Task 2.3 (SOFC Scaleup for Hybrid and Fuel Cell Systems) under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL), entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. This study analyzes the performance and economics of power generation systems for central power generation application based on Solid Oxide Fuel Cell (SOFC) technology and fueled by natural gas. The main objective of this task is to develop credible scale up strategies for large solid oxide fuel cell-gas turbine systems. System concepts that integrate a SOFC with a gas turbine were developed and analyzed for plant sizes in excess of 20 MW. A 25 MW plant configuration was selected with projected system efficiency of over 65% and a factory cost of under $400/kW. The plant design is modular and can be scaled to both higher and lower plant power ratings. Technology gaps and required engineering development efforts were identified and evaluated.

  9. Emissions Benefits of Distributed Generation in the Texas Market

    SciTech Connect

    Hadley, SW

    2005-06-16

    One potential benefit of distributed generation (DG) is a net reduction in air emissions. While DG will produce emissions, most notably carbon dioxide and nitrogen oxides, the power it displaces might have produced more. This study used a system dispatch model developed at Oak Ridge National Laboratory to simulate the 2012 Texas power market with and without DG. This study compares the reduction in system emissions to the emissions from the DG to determine the net savings. Some of the major findings are that 85% of the electricity displaced by DG during peak hours will be simple cycle natural gas, either steam or combustion turbine. Even with DG running as baseload, 57% of electricity displaced will be simple cycle natural gas. Despite the retirement of some gas-fired steam units and the construction of many new gas turbine and combined cycle units, the marginal emissions from the system remain quite high (1.4 lb NO{sub x}/MWh on peak and 1.1 lb NO{sub x}/MWh baseload) compared to projected DG emissions. Consequently, additions of DG capacity will reduce emissions in Texas from power generation in 2012. Using the DG exhaust heat for combined heat and power provides an even greater benefit, since it eliminates further boiler emissions while adding none over what would be produced while generating electricity. Further studies are warranted concerning the robustness of the result with changes in fuel prices, demands, and mixes of power generating technology.

  10. Evidence for Nanoflare Heating of the Solar Corona from the EUNIS Sounding Rocket

    NASA Astrophysics Data System (ADS)

    Brosius, J. W.; Daw, A. N.; Rabin, D. M.

    2015-12-01

    We present spatially resolved EUV spectroscopic measurements ofpervasive, faint Fe XIX 592.2 A line emission in AR 11726,observed during the 2013 April 23 flight of the Extreme UltravioletNormal Incidence Spectrograph (EUNIS-13) sounding rocket instrument. With cooled detectors, high sensitivity, and high spectralresolution, EUNIS-13 resolves the lines of Fe XIX at 592.2 A (formedat temperature T around 8.9 MK) and Fe XII at 592.6 A (T around 1.6MK). The Fe XIX line emission, observed over an area in excess of4920 square arcsec (2.58x10^9 square km, more than 60% of the activeregion), provides strong evidence for the nanoflare heating model ofthe solar corona. No GOES events occurred in the region less than 2hours before the rocket flight, but a microflare was observed northand east of the region with RHESSI and EUNIS during the flight. Theabsence of significant upward velocities anywhere in the region,particularly the microflare, indicates that the pervasive Fe XIXemission is not propelled outward from the microflare site, but ismost likely attributed to localized heating (due to reconnection,wave dissipation, or some other mechanism) consistent with thenanoflare heating model of the solar corona. We measure average FeXIX/Fe XII intensity ratios of 0.070 outside the AR core, 0.22 inarea of bright coronal emission (the area in which the Fe XIIintensity exceeds half its maximum observed value), and 0.55 in theregion's hot core. Using the CHIANTI atomic physics database andassuming ionization equilibrium, we estimate corresponding Fe XIX/FeXII emission measure ratios of about 0.076, 0.23 and 0.59. Theemission measure ratios must be viewed with caution in light oflingering uncertainties in the Fe XII contribution functions.EUNIS-13 was supported by the NASA Heliophysics Division through itsLow Cost Access to Space program.

  11. Time series power flow analysis for distribution connected PV generation.

    SciTech Connect

    Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J.; Smith, Jeff; Dugan, Roger

    2013-01-01

    Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating

  12. Laboratory air bubble generation of various size distributions

    SciTech Connect

    Puleo, Jack A.; Johnson, Rex V.; Kooney, Tim N.

    2004-11-01

    Air bubble size in aqueous environments is an important factor governing natural processes ranging from fluid/atmosphere gas transfer to noise production. Bubbles are also known to affect various scientific instruments. In this study we investigate the production capability of eight inexpensive bubble generators using optical imaging techniques. Specific emphasis is directed towards determining bubble size and distribution for a given device, flow conditions, and type of water used (fresh vs salt). In almost all cases tested here, bubbles produced in salt water were more numerous, and smaller than for the same bubbler and conditions in fresh water. For porous media, the finer the pore size, the smaller the bubble produced with some variation depending on thickness of material containing the pore and water type. While no single generator tested was capable of spanning all the bubble sizes observed (100 to 6000 microns), the data contained herein will enable proper choice of bubbler or combinations thereof for future studies depending on the size and distribution of bubbles required.

  13. Automatic generation of water distribution systems based on GIS data.

    PubMed

    Sitzenfrei, Robert; Möderl, Michael; Rauch, Wolfgang

    2013-09-01

    In the field of water distribution system (WDS) analysis, case study research is needed for testing or benchmarking optimisation strategies and newly developed software. However, data availability for the investigation of real cases is limited due to time and cost needed for data collection and model setup. We present a new algorithm that addresses this problem by generating WDSs from GIS using population density, housing density and elevation as input data. We show that the resulting WDSs are comparable to actual systems in terms of network properties and hydraulic performance. For example, comparing the pressure heads for an actual and a generated WDS results in pressure head differences of ±4 m or less for 75% of the supply area. Although elements like valves and pumps are not included, the new methodology can provide water distribution systems of varying levels of complexity (e.g., network layouts, connectivity, etc.) to allow testing design/optimisation algorithms on a large number of networks. The new approach can be used to estimate the construction costs of planned WDSs aimed at addressing population growth or at comparisons of different expansion strategies in growth corridors.

  14. Improved Quantum Artificial Fish Algorithm Application to Distributed Network Considering Distributed Generation.

    PubMed

    Du, Tingsong; Hu, Yang; Ke, Xianting

    2015-01-01

    An improved quantum artificial fish swarm algorithm (IQAFSA) for solving distributed network programming considering distributed generation is proposed in this work. The IQAFSA based on quantum computing which has exponential acceleration for heuristic algorithm uses quantum bits to code artificial fish and quantum revolving gate, preying behavior, and following behavior and variation of quantum artificial fish to update the artificial fish for searching for optimal value. Then, we apply the proposed new algorithm, the quantum artificial fish swarm algorithm (QAFSA), the basic artificial fish swarm algorithm (BAFSA), and the global edition artificial fish swarm algorithm (GAFSA) to the simulation experiments for some typical test functions, respectively. The simulation results demonstrate that the proposed algorithm can escape from the local extremum effectively and has higher convergence speed and better accuracy. Finally, applying IQAFSA to distributed network problems and the simulation results for 33-bus radial distribution network system show that IQAFSA can get the minimum power loss after comparing with BAFSA, GAFSA, and QAFSA.

  15. 46 CFR 111.05-17 - Generation and distribution system grounding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Generation and distribution system grounding. 111.05-17... Generation and distribution system grounding. The neutral of each grounded generation and distribution system must: (a) Be grounded at the generator switchboard, except the neutral of an emergency power...

  16. 46 CFR 111.05-17 - Generation and distribution system grounding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Generation and distribution system grounding. 111.05-17... Generation and distribution system grounding. The neutral of each grounded generation and distribution system must: (a) Be grounded at the generator switchboard, except the neutral of an emergency power...

  17. 46 CFR 111.05-17 - Generation and distribution system grounding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Generation and distribution system grounding. 111.05-17... Generation and distribution system grounding. The neutral of each grounded generation and distribution system must: (a) Be grounded at the generator switchboard, except the neutral of an emergency power...

  18. Pervasive faint Fe XIX emission from a solar active region observed with EUNIS-13: Evidence for nanoflare heating

    SciTech Connect

    Brosius, Jeffrey W.; Daw, Adrian N.; Rabin, D. M.

    2014-08-01

    We present spatially resolved EUV spectroscopic measurements of pervasive, faint Fe XIX 592.2 Å line emission in an active region observed during the 2013 April 23 flight of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS-13) sounding rocket instrument. With cooled detectors, high sensitivity, and high spectral resolution, EUNIS-13 resolves the lines of Fe XIX at 592.2 Å (formed at temperature T ≈ 8.9 MK) and Fe XII at 592.6 Å (T ≈ 1.6 MK). The Fe XIX line emission, observed over an area in excess of 4920 arcsec{sup 2} (2.58 × 10{sup 9} km{sup 2}, more than 60% of the active region), provides strong evidence for the nanoflare heating model of the solar corona. No GOES events occurred in the region less than 2 hr before the rocket flight, but a microflare was observed north and east of the region with RHESSI and EUNIS during the flight. The absence of significant upward velocities anywhere in the region, particularly the microflare, indicates that the pervasive Fe XIX emission is not propelled outward from the microflare site, but is most likely attributed to localized heating (not necessarily due to reconnection) consistent with the nanoflare heating model of the solar corona. Assuming ionization equilibrium we estimate Fe XIX/Fe XII emission measure ratios of ∼0.076 just outside the AR core and ∼0.59 in the core.

  19. Experimental comparison of PV-smoothing controllers using distributed generators

    SciTech Connect

    Johnson, Jay Dean; Ellis, Abraham; Denda, Atsushi; Morino, Kimio; Hawkins, John N.; Arellano, Brian; Shinji, Takao; Ogata, Takao; Tadokoro, Masayuki

    2014-02-01

    The power output variability of photovoltaic systems can affect local electrical grids in locations with high renewable energy penetrations or weak distribution or transmission systems. In those rare cases, quick controllable generators (e.g., energy storage systems) or loads can counteract the destabilizing effects by compensating for the power fluctuations. Previously, control algorithms for coordinated and uncoordinated operation of a small natural gas engine-generator (genset) and a battery for smoothing PV plant output were optimized using MATLAB/Simulink simulations. The simulations demonstrated that a traditional generation resource such as a natural gas genset in combination with a battery would smooth the photovoltaic output while using a smaller battery state of charge (SOC) range and extending the life of the battery. This paper reports on the experimental implementation of the coordinated and uncoordinated controllers to verify the simulations and determine the differences in the controllers. The experiments were performed with the PNM PV and energy storage Prosperity site and a gas engine-generator located at the Aperture Center at Mesa Del Sol in Albuquerque, New Mexico. Two field demonstrations were performed to compare the different PV smoothing control algorithms: (1) implementing the coordinated and uncoordinated controls while switching off a subsection of the PV array at precise times on successive clear days, and (2) comparing the results of the battery and genset outputs for the coordinated control on a high variability day with simulations of the coordinated and uncoordinated controls. It was found that for certain PV power profiles the SOC range of the battery may be larger with the coordinated control, but the total amp-hours through the battery-which approximates battery wear-will always be smaller with the coordinated control.

  20. A reformer to generate hydrogen for distributed power applications

    SciTech Connect

    Cole, J.A.; Kumar, R.V.; West, J.; Lyon, R.K.

    1998-07-01

    The generation of power using fuel cells is a promising technology for distributed electric power generation applications. Steam reforming of fossil fuels remains the most thermodynamically efficient means for production of hydrogen. Unfortunately, current steam reforming technology achieves high efficiencies only at very large scales, and remains impractical at the small production rates needed for small- to medium-size distributed power applications. A novel reformer process, called unmixed reforming, or UMR, has been developed for the conversion of hydrocarbon fuels (natural gas, diesel, gasoline) to hydrogen. The reformer promises high thermodynamic efficiency as heat is generated right on the catalytic bed unlike conventional reforming. The controlled combustion on the reforming catalyst using a patented technology called unmixed combustion provides the heat for the endothermic reforming reaction. The reformer generates a high-purity hydrogen product stream, which can then be used by fuel cells with minimal processing. The unmixed reformer is a packed-bed consisting of finely divided nickel supported on a ceramic matrix mixed with a calcium oxide bearing matrix such as dolomite. UMR consists of three process steps. During the first step air is passed over the packed-bed reactor to oxidize the nickel. The heat released during the oxidation reaction raises the temperature of the bed and decomposes the dolomite releasing carbon dioxide into a vent gas stream. In the subsequent step fuel passed over the packed-bed reduces the NiO back to Ni and further increases the temperature. In the final step, fuel and steam react to produce hydrogen through conventional steam reforming chemistry. The calcium oxide captures some of the carbon dioxide formed during the reforming reaction and thus shifts the reforming reactions to higher conversions, hence improving the purity of the hydrogen product stream. Although product hydrogen concentrations may be 75--85%, the CO content

  1. Microwave pyrolysis of wheat straw: product distribution and generation mechanism.

    PubMed

    Zhao, Xiqiang; Wang, Wenlong; Liu, Hongzhen; Ma, Chunyuan; Song, Zhanlong

    2014-04-01

    Microwave pyrolysis of wheat straw is studied, combined with analysis of products, the distribution and generation pathway of products are investigated. Only a small amount of volatiles released when microwave pyrolysis of pure straw. Mixtures of adding CuO and Fe3O4 can pyrolyze, and the majority in pyrolysis products is in liquid-phase. Severe pyrolysis occur after adding carbon residue, the CO content in pyrolysis gas products is high, and the maximum volume content of H2 can exceed 35 vol.%. The high-temperature is helpful for increasing the yield of combustible gas in gaseous products, in particular the H2 production, but also helpful for improving the conversion of sample. Pyrolysis is carried out layer by layer from the inside to outside. As the internal material firstly pyrolyze and pyrolysis products released pass through the low temperature zone, the chance of occurrence of secondary reactions is reduced.

  2. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Kurt Montgomery; Nguyen Minh

    2003-08-01

    This report summarizes the work performed by Honeywell during the October 2001 to December 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. The conceptual and demonstration system designs were proposed and analyzed, and these systems have been modeled in Aspen Plus. Work has also started on the assembly of dynamic component models and the development of the top-level controls requirements for the system. SOFC stacks have been fabricated and performance mapping initiated.

  3. Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation

    SciTech Connect

    Nguyen Minh

    2002-03-31

    This report summarizes the work performed by Honeywell during the January 2002 to March 2002 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. For this reporting period the following activities have been carried out: {lg_bullet} Conceptual system design trade studies were performed {lg_bullet} System-level performance model was created {lg_bullet} Dynamic control models are being developed {lg_bullet} Mechanical properties of candidate heat exchanger materials were investigated {lg_bullet} SOFC performance mapping as a function of flow rate and pressure was completed

  4. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Unknown

    2002-03-01

    This report summarizes the work performed by Honeywell during the July 2001 to September 2001 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a turbogenerator. An internal program kickoff was held at Honeywell in Torrance, CA. The program structure was outlined and the overall technical approach for the program was presented to the team members. Detail program schedules were developed and detailed objectives were defined. Initial work has begun on the system design and pressurized SOFC operation.

  5. U.S. distributed generation fuel cell program

    NASA Astrophysics Data System (ADS)

    Williams, M. C.; Strakey, J. P.; Singhal, Subhash C.

    The Department of Energy (DOE) is the largest funder of fuel cell technology in the U.S. The Department of Energy—Office of Fossil Energy (FE) is developing high temperature fuel cells for distributed generation. It has funded the development of tubular solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) power systems operating at up to 60% efficiency on natural gas. The remarkable environmental performance of these fuel cells makes them likely candidates to help mitigate pollution. DOE is now pursuing more widely applicable solid oxide fuel cells for 2010 and beyond. DOE estimates that a 5 kW solid oxide fuel cell system can reach $400 per kW at reasonable manufacturing volumes. SECA—the Solid State Energy Conversion Alliance—was formed by the National Energy Technology Laboratory (NETL) and the Pacific Northwest National Laboratory (PNNL) to accelerate the commercial readiness of planar and other solid oxide fuel cell systems utilizing 3-10 kW size modules by taking advantage of the projected economies of production from a "mass customization" approach. In addition, if the modular 3-10 kW size units can be "ganged" or "scaled-up" to larger sizes with no increase in cost, then commercial, microgrid, and other distributed generation markets will become attainable. Further scale-up and hybridization of SECA SOFCs with gas turbines could result in penetration of the bulk power market. This paper reviews the current status of the solid oxide and molten carbonate fuel cells in the U.S.

  6. Distributed Generators Allocation in Radial Distribution Systems with Load Growth using Loss Sensitivity Approach

    NASA Astrophysics Data System (ADS)

    Kumar, Ashwani; Vijay Babu, P.; Murty, V. V. S. N.

    2016-07-01

    Rapidly increasing electricity demands and capacity shortage of transmission and distribution facilities are the main driving forces for the growth of distributed generation (DG) integration in power grids. One of the reasons for choosing a DG is its ability to support voltage in a distribution system. Selection of effective DG characteristics and DG parameters is a significant concern of distribution system planners to obtain maximum potential benefits from the DG unit. The objective of the paper is to reduce the power losses and improve the voltage profile of the radial distribution system with optimal allocation of the multiple DG in the system. The main contribution in this paper is (i) combined power loss sensitivity (CPLS) based method for multiple DG locations, (ii) determination of optimal sizes for multiple DG units at unity and lagging power factor, (iii) impact of DG installed at optimal, that is, combined load power factor on the system performance, (iv) impact of load growth on optimal DG planning, (v) Impact of DG integration in distribution systems on voltage stability index, (vi) Economic and technical Impact of DG integration in the distribution systems. The load growth factor has been considered in the study which is essential for planning and expansion of the existing systems. The technical and economic aspects are investigated in terms of improvement in voltage profile, reduction in total power losses, cost of energy loss, cost of power obtained from DG, cost of power intake from the substation, and savings in cost of energy loss. The results are obtained on IEEE 69-bus radial distribution systems and also compared with other existing methods.

  7. SOLID OXIDE FUEL CELL HYBRID SYSTEM FOR DISTRIBUTED POWER GENERATION

    SciTech Connect

    Faress Rahman; Nguyen Minh

    2003-07-01

    This report summarizes the work performed by Hybrid Power Generation Systems, LLC during the January 2003 to June 2003 reporting period under Cooperative Agreement DE-FC26-01NT40779 for the U. S. Department of Energy, National Energy Technology Laboratory (DOE/NETL) entitled ''Solid Oxide Fuel Cell Hybrid System for Distributed Power Generation''. The main objective of this project is to develop and demonstrate the feasibility of a highly efficient hybrid system integrating a planar Solid Oxide Fuel Cell (SOFC) and a micro-turbine. In addition, an activity included in this program focuses on the development of an integrated coal gasification fuel cell system concept based on planar SOFC technology. This report summarizes the results obtained to date on: System performance analysis and model optimization; Reliability and cost model development; System control including dynamic model development; Heat exchanger material tests and life analysis; Pressurized SOFC evaluation; and Pre-baseline system definition for coal gasification fuel cell system concept.

  8. Investment and Upgrade in Distributed Generation under Uncertainty

    SciTech Connect

    Siddiqui, Afzal; Maribu, Karl

    2008-08-18

    The ongoing deregulation of electricity industries worldwide is providing incentives for microgrids to use small-scale distributed generation (DG) and combined heat and power (CHP) applications via heat exchangers (HXs) to meet local energy loads. Although the electric-only efficiency of DG is lower than that of central-station production, relatively high tariff rates and the potential for CHP applications increase the attraction of on-site generation. Nevertheless, a microgrid contemplatingthe installation of gas-fired DG has to be aware of the uncertainty in the natural gas price. Treatment of uncertainty via real options increases the value of the investment opportunity, which then delays the adoption decision as the opportunity cost of exercising the investment option increases as well. In this paper, we take the perspective of a microgrid that can proceed in a sequential manner with DG capacity and HX investment in order to reduce its exposure to risk from natural gas price volatility. In particular, with the availability of the HX, the microgrid faces a tradeoff between reducing its exposure to the natural gas price and maximising its cost savings. By varying the volatility parameter, we find that the microgrid prefers a direct investment strategy for low levels of volatility and a sequential one for higher levels of volatility.

  9. Air Quality Impact of Distributed Generation of Electricity

    NASA Astrophysics Data System (ADS)

    Jing, Qiguo

    This dissertation summarizes the results of a five-year investigation of the impact of distributed generation (DG) of electricity on air quality in urban areas. I focused on the impact of power plants with capacities of less than 50 MW, which is typical of DG units in urban areas. These power plants are modeled as buoyant emissions from stacks less than 10 m situated in the midst of urban buildings. Because existing dispersion models are not designed for such sources, the first step of the study involved the evaluation of AERMOD, USEPA's state-of-the art dispersion model, with data collected in a tracer study conducted in the vicinity of a DG unit. The second step of the study consisted of using AERMOD to compare the impact of DG penetration in the South Coast Air Basin of Los Angeles with the impact of replacing DG generation with expansion of current central power plant capacity. The third topic of my investigation is the development and application of a model to examine the impact of non-power plant sources in a large urban area such as Los Angeles. This model can be used to estimate the air quality impact of DG relative to other sources in an urban area. The first part of this dissertation describes a tracer study conducted in Palm Springs, CA. Concentrations observed during the nighttime experiments are generally higher than those measured during the daytime experiments. They fall off less rapidly with distance than during the daytime. AERMOD provides an adequate description of concentrations associated with the buoyant releases from the DG during the daytime when turbulence is controlled by convection induced by solar heating. However, AERMOD underestimates concentrations during the night when turbulence is generated by wind shear. Also, AERMOD predicts a decrease in concentrations with distance that is much more rapid than the relatively flat observed decrease. I have suggested modifications to AERMOD to improve the agreement between model estimates and

  10. A Model of U.S. Commercial Distributed Generation Adoption

    SciTech Connect

    LaCommare, Kristina Hamachi; Ryan Firestone; Zhou, Nan; Maribu,Karl; Marnay, Chris

    2006-01-10

    Small-scale (100 kW-5 MW) on-site distributed generation (DG) economically driven by combined heat and power (CHP) applications and, in some cases, reliability concerns will likely emerge as a common feature of commercial building energy systems over the next two decades. Forecasts of DG adoption published by the Energy Information Administration (EIA) in the Annual Energy Outlook (AEO) are made using the National Energy Modeling System (NEMS), which has a forecasting module that predicts the penetration of several possible commercial building DG technologies over the period 2005-2025. NEMS is also used for estimating the future benefits of Department of Energy research and development used in support of budget requests and management decisionmaking. The NEMS approach to modeling DG has some limitations, including constraints on the amount of DG allowed for retrofits to existing buildings and a small number of possible sizes for each DG technology. An alternative approach called Commercial Sector Model (ComSeM) is developed to improve the way in which DG adoption is modeled. The approach incorporates load shapes for specific end uses in specific building types in specific regions, e.g., cooling in hospitals in Atlanta or space heating in Chicago offices. The Distributed Energy Resources Customer Adoption Model (DER-CAM) uses these load profiles together with input cost and performance DG technology assumptions to model the potential DG adoption for four selected cities and two sizes of five building types in selected forecast years to 2022. The Distributed Energy Resources Market Diffusion Model (DER-MaDiM) is then used to then tailor the DER-CAM results to adoption projections for the entire U.S. commercial sector for all forecast years from 2007-2025. This process is conducted such that the structure of results are consistent with the structure of NEMS, and can be re-injected into NEMS that can then be used to integrate adoption results into a full forecast.

  11. Microgrids and distributed generation systems: Control, operation, coordination and planning

    NASA Astrophysics Data System (ADS)

    Che, Liang

    Distributed Energy Resources (DERs) which include distributed generations (DGs), distributed energy storage systems, and adjustable loads are key components in microgrid operations. A microgrid is a small electric power system integrated with on-site DERs to serve all or some portion of the local load and connected to the utility grid through the point of common coupling (PCC). Microgrids can operate in both grid-connected mode and island mode. The structure and components of hierarchical control for a microgrid at Illinois Institute of Technology (IIT) are discussed and analyzed. Case studies would address the reliable and economic operation of IIT microgrid. The simulation results of IIT microgrid operation demonstrate that the hierarchical control and the coordination strategy of distributed energy resources (DERs) is an effective way of optimizing the economic operation and the reliability of microgrids. The benefits and challenges of DC microgrids are addressed with a DC model for the IIT microgrid. We presented the hierarchical control strategy including the primary, secondary, and tertiary controls for economic operation and the resilience of a DC microgrid. The simulation results verify that the proposed coordinated strategy is an effective way of ensuring the resilient response of DC microgrids to emergencies and optimizing their economic operation at steady state. The concept and prototype of a community microgrid that interconnecting multiple microgrids in a community are proposed. Two works are conducted. For the coordination, novel three-level hierarchical coordination strategy to coordinate the optimal power exchanges among neighboring microgrids is proposed. For the planning, a multi-microgrid interconnection planning framework using probabilistic minimal cut-set (MCS) based iterative methodology is proposed for enhancing the economic, resilience, and reliability signals in multi-microgrid operations. The implementation of high-reliability microgrids

  12. Distributed generation system using wind/photovoltaic/fuel cell

    NASA Astrophysics Data System (ADS)

    Buasri, Panhathai

    This dissertation investigates the performance and the operation of a distributed generation (DG) power system using wind/photovoltaic/fuel cell (W/PV/FC). The power system consists of a 2500 W photovoltaic array subsystem, a 500 W proton exchange membrane fuel cell (PEMFC) stack subsystem, 300 W wind turbine, 500 W wind turbine, and 1500 W wind energy conversion subsystems. To extract maximum power from the PV, a maximum power point tracker was designed and fabricated. A 4 kW single phase inverter was used to convert the DC voltage to AC voltage; also a 44 kWh battery bank was used to store energy and prevent fluctuation of the power output of the DG system. To connect the fuel cell to the batteries, a DC/DC controller was designed and fabricated. To monitor and study the performance of the DG system under variable conditions, a data acquisition system was designed and installed. The fuel cell subsystem performance was evaluated under standalone operation using a variable resistance and under interactive mode, connected to the batteries. The manufacturing data and the experimental data were used to develop an electrical circuit model to the fuel cell. Furthermore, harmonic analysis of the DG system was investigated. For an inverter, the AC voltage delivered to the grid changed depending on the time, load, and electronic equipment that was connected. The quality of the DG system was evaluated by investigating the harmonics generated by the power electronics converters. Finally, each individual subsystem of the DG system was modeled using the neuro-fuzzy approach. The model was used to predict the performance of the DG system under variable conditions, such as passing clouds and wind gust conditions. The steady-state behaviors of the model were validated by the experimental results under different operating conditions.

  13. GENERIC VERIFICATION PROTOCOL: DISTRIBUTED GENERATION AND COMBINED HEAT AND POWER FIELD TESTING PROTOCOL

    EPA Science Inventory

    This report is a generic verification protocol by which EPA’s Environmental Technology Verification program tests newly developed equipment for distributed generation of electric power, usually micro-turbine generators and internal combustion engine generators. The protocol will ...

  14. Voltage management of distribution networks with high penetration of distributed photovoltaic generation sources

    NASA Astrophysics Data System (ADS)

    Alyami, Saeed

    Installation of photovoltaic (PV) units could lead to great challenges to the existing electrical systems. Issues such as voltage rise, protection coordination, islanding detection, harmonics, increased or changed short-circuit levels, etc., need to be carefully addressed before we can see a wide adoption of this environmentally friendly technology. Voltage rise or overvoltage issues are of particular importance to be addressed for deploying more PV systems to distribution networks. This dissertation proposes a comprehensive solution to deal with the voltage violations in distribution networks, from controlling PV power outputs and electricity consumption of smart appliances in real time to optimal placement of PVs at the planning stage. The dissertation is composed of three parts: the literature review, the work that has already been done and the future research tasks. An overview on renewable energy generation and its challenges are given in Chapter 1. The overall literature survey, motivation and the scope of study are also outlined in the chapter. Detailed literature reviews are given in the rest of chapters. The overvoltage and undervoltage phenomena in typical distribution networks with integration of PVs are further explained in Chapter 2. Possible approaches for voltage quality control are also discussed in this chapter, followed by the discussion on the importance of the load management for PHEVs and appliances and its benefits to electric utilities and end users. A new real power capping method is presented in Chapter 3 to prevent overvoltage by adaptively setting the power caps for PV inverters in real time. The proposed method can maintain voltage profiles below a pre-set upper limit while maximizing the PV generation and fairly distributing the real power curtailments among all the PV systems in the network. As a result, each of the PV systems in the network has equal opportunity to generate electricity and shares the responsibility of voltage

  15. Distributed feedback laser diode integrated with distributed Bragg reflector for continuous-wave terahertz generation.

    PubMed

    Kim, Namje; Han, Sang-Pil; Ryu, Han-Cheol; Ko, Hyunsung; Park, Jeong-Woo; Lee, Donghun; Jeon, Min Yong; Park, Kyung Hyun

    2012-07-30

    A widely tunable dual mode laser diode with a single cavity structure is demonstrated. This novel device consists of a distributed feedback (DFB) laser diode and distributed Bragg reflector (DBR). Micro-heaters are integrated on the top of each section for continuous and independent wavelength tuning of each mode. By using a single gain medium in the DFB section, an effective common optical cavity and common modes are realized. The laser diode shows a wide tunability of the optical beat frequency, from 0.48 THz to over 2.36 THz. Continuous wave THz radiation is also successfully generated with low-temperature grown InGaAs photomixers from 0.48 GHz to 1.5 THz.

  16. Improved Quantum Artificial Fish Algorithm Application to Distributed Network Considering Distributed Generation

    PubMed Central

    Du, Tingsong; Hu, Yang; Ke, Xianting

    2015-01-01

    An improved quantum artificial fish swarm algorithm (IQAFSA) for solving distributed network programming considering distributed generation is proposed in this work. The IQAFSA based on quantum computing which has exponential acceleration for heuristic algorithm uses quantum bits to code artificial fish and quantum revolving gate, preying behavior, and following behavior and variation of quantum artificial fish to update the artificial fish for searching for optimal value. Then, we apply the proposed new algorithm, the quantum artificial fish swarm algorithm (QAFSA), the basic artificial fish swarm algorithm (BAFSA), and the global edition artificial fish swarm algorithm (GAFSA) to the simulation experiments for some typical test functions, respectively. The simulation results demonstrate that the proposed algorithm can escape from the local extremum effectively and has higher convergence speed and better accuracy. Finally, applying IQAFSA to distributed network problems and the simulation results for 33-bus radial distribution network system show that IQAFSA can get the minimum power loss after comparing with BAFSA, GAFSA, and QAFSA. PMID:26447713

  17. Enhanced power quality based single phase photovoltaic distributed generation system

    NASA Astrophysics Data System (ADS)

    Panda, Aurobinda; Pathak, M. K.; Srivastava, S. P.

    2016-08-01

    This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.

  18. A stochastic evolutionary model generating a mixture of exponential distributions

    NASA Astrophysics Data System (ADS)

    Fenner, Trevor; Levene, Mark; Loizou, George

    2016-02-01

    Recent interest in human dynamics has stimulated the investigation of the stochastic processes that explain human behaviour in various contexts, such as mobile phone networks and social media. In this paper, we extend the stochastic urn-based model proposed in [T. Fenner, M. Levene, G. Loizou, J. Stat. Mech. 2015, P08015 (2015)] so that it can generate mixture models, in particular, a mixture of exponential distributions. The model is designed to capture the dynamics of survival analysis, traditionally employed in clinical trials, reliability analysis in engineering, and more recently in the analysis of large data sets recording human dynamics. The mixture modelling approach, which is relatively simple and well understood, is very effective in capturing heterogeneity in data. We provide empirical evidence for the validity of the model, using a data set of popular search engine queries collected over a period of 114 months. We show that the survival function of these queries is closely matched by the exponential mixture solution for our model.

  19. Greenhouse Gas Abatement with Distributed Generation in California's Commercial Buildings

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Cardoso, Goncalo; Megel, Olivier; Siddiqui, Afzal; Lai, Judy

    2009-08-15

    Lawrence Berkeley National Laboratory (LBL) is working with the California Energy Commission (CEC) to determine the role of distributed generation (DG) in greenhouse gas reductions. The impact of DG on large industrial sites is well known, and mostly, the potentials are already harvested. In contrast, little is known about the impact of DG on commercial buildings with peak electric loads ranging from 100 kW to 5 MW. We examine how DG with combined heat and power (CHP) may be implemented within the context of a cost minimizing microgrid that is able to adopt and operate various smart energy technologies, such as thermal and photovoltaic (PV) on-site generation, heat exchangers, solar thermal collectors, absorption chillers, and storage systems. We use a mixed-integer linear program (MILP) that has the minimization of a site's annual energy costs as objective. Using 138 representative commercial sites in California (CA) with existing tariff rates and technology data, we find the greenhouse gas reduction potential for California's commercial sector. This paper shows results from the ongoing research project and finished work from a two year U.S. Department of Energy research project. To show the impact of the different technologies on CO2 emissions, several sensitivity runs for different climate zones within CA with different technology performance expectations for 2020 were performed. The considered sites can contribute between 1 Mt/a and 1.8 Mt/a to the California Air Resources Board (CARB) goal of 6.7Mt/a CO2 abatement potential in 2020. Also, with lower PV and storage costs as well as consideration of a CO2 pricing scheme, our results indicate that PV and electric storage adoption can compete rather than supplement each other when the tariff structure and costs of electricity supply have been taken into consideration. To satisfy the site's objective of minimizing energy costs, the batteries will be charged also by CHP systems during off-peak and mid-peak hours and

  20. Modeling and control of fuel cell based distributed generation systems

    NASA Astrophysics Data System (ADS)

    Jung, Jin Woo

    This dissertation presents circuit models and control algorithms of fuel cell based distributed generation systems (DGS) for two DGS topologies. In the first topology, each DGS unit utilizes a battery in parallel to the fuel cell in a standalone AC power plant and a grid-interconnection. In the second topology, a Z-source converter, which employs both the L and C passive components and shoot-through zero vectors instead of the conventional DC/DC boost power converter in order to step up the DC-link voltage, is adopted for a standalone AC power supply. In Topology 1, two applications are studied: a standalone power generation (Single DGS Unit and Two DGS Units) and a grid-interconnection. First, dynamic model of the fuel cell is given based on electrochemical process. Second, two full-bridge DC to DC converters are adopted and their controllers are designed: an unidirectional full-bridge DC to DC boost converter for the fuel cell and a bidirectional full-bridge DC to DC buck/boost converter for the battery. Third, for a three-phase DC to AC inverter without or with a Delta/Y transformer, a discrete-time state space circuit model is given and two discrete-time feedback controllers are designed: voltage controller in the outer loop and current controller in the inner loop. And last, for load sharing of two DGS units and power flow control of two DGS units or the DGS connected to the grid, real and reactive power controllers are proposed. Particularly, for the grid-connected DGS application, a synchronization issue between an islanding mode and a paralleling mode to the grid is investigated, and two case studies are performed. To demonstrate the proposed circuit models and control strategies, simulation test-beds using Matlab/Simulink are constructed for each configuration of the fuel cell based DGS with a three-phase AC 120 V (L-N)/60 Hz/50 kVA and various simulation results are presented. In Topology 2, this dissertation presents system modeling, modified space

  1. Method and apparatus for anti-islanding protection of distributed generations

    DOEpatents

    Ye, Zhihong; John, Vinod; Wang, Changyong; Garces, Luis Jose; Zhou, Rui; Li, Lei; Walling, Reigh Allen; Premerlani, William James; Sanza, Peter Claudius; Liu, Yan; Dame, Mark Edward

    2006-03-21

    An apparatus for anti-islanding protection of a distributed generation with respect to a feeder connected to an electrical grid is disclosed. The apparatus includes a sensor adapted to generate a voltage signal representative of an output voltage and/or a current signal representative of an output current at the distributed generation, and a controller responsive to the signals from the sensor. The controller is productive of a control signal directed to the distributed generation to drive an operating characteristic of the distributed generation out of a nominal range in response to the electrical grid being disconnected from the feeder.

  2. Voltage Control of Distribution Network with a Large Penetration of Photovoltaic Generations using FACTS Devices

    NASA Astrophysics Data System (ADS)

    Kondo, Taro; Baba, Jumpei; Yokoyama, Akihiko

    In recent years, there is a great deal of interest in distributed generations from viewpoints of environmental problem and energy saving measure. Thus, a lot of distributed generators will be connected to the distribution network in the future. However, increase of distributed generators, which convert natural energy into electric energy, is concerned on their adverse effects on distribution network. Therefore, control of distribution networks using Flexible AC Transmission System (FACTS) devices is considered in order to adjust the voltage profile, and as a result more distributed generations can be installed into the networks. In this paper, four types of FACTS devices, Static Synchronous Compensator (STATCOM), Static Synchronous Series Compensator (SSSC), Unified Power Flow Controller (UPFC) and self-commutated Back-To-Back converter (BTB), are analyzed by comparison of required minimum capacity of the inverters in a residential distribution network with a large penetration of photovoltaic generations.

  3. Network Capacity Assessment of CHP-based Distributed Generation on Urban Energy Distribution Networks

    NASA Astrophysics Data System (ADS)

    Zhang, Xianjun

    The combined heat and power (CHP)-based distributed generation (DG) or dis-tributed energy resources (DERs) are mature options available in the present energy market, considered to be an effective solution to promote energy efficiency. In the urban environment, the electricity, water and natural gas distribution networks are becoming increasingly interconnected with the growing penetration of the CHP-based DG. Subsequently, this emerging interdependence leads to new topics meriting serious consideration: how much of the CHP-based DG can be accommodated and where to locate these DERs, and given preexisting constraints, how to quantify the mutual impacts on operation performances between these urban energy distribution networks and the CHP-based DG. The early research work was conducted to investigate the feasibility and design methods for one residential microgrid system based on existing electricity, water and gas infrastructures of a residential community, mainly focusing on the economic planning. However, this proposed design method cannot determine the optimal DG sizing and siting for a larger test bed with the given information of energy infrastructures. In this context, a more systematic as well as generalized approach should be developed to solve these problems. In the later study, the model architecture that integrates urban electricity, water and gas distribution networks, and the CHP-based DG system was developed. The proposed approach addressed the challenge of identifying the optimal sizing and siting of the CHP-based DG on these urban energy networks and the mutual impacts on operation performances were also quantified. For this study, the overall objective is to maximize the electrical output and recovered thermal output of the CHP-based DG units. The electricity, gas, and water system models were developed individually and coupled by the developed CHP-based DG system model. The resultant integrated system model is used to constrain the DG's electrical

  4. Methods for Dynamic Analysis of Distribution Feeders with High Penetration of PV Generators

    SciTech Connect

    Nagarajan, Adarsh; Ayyanar, Raja

    2016-11-21

    An increase in the number of inverter-interfaced photovoltaic (PV) generators on existing distribution feeders affects the design, operation, and control of the distribution systems. Existing distribution system analysis tools are capable of supporting only snapshot and quasi-static analyses. Capturing the dynamic effects of PV generators during the variation in distribution system states is necessary when studying the effects of controller bandwidths, multiple voltage correction devices, and anti-islanding. This work explores the use of dynamic phasors and differential algebraic equations (DAE) for impact analysis of PV generators on the existing distribution feeders.

  5. A second generation distributed point polarizable water model.

    PubMed

    Kumar, Revati; Wang, Fang-Fang; Jenness, Glen R; Jordan, Kenneth D

    2010-01-07

    A distributed point polarizable model (DPP2) for water, with explicit terms for charge penetration, induction, and charge transfer, is introduced. The DPP2 model accurately describes the interaction energies in small and large water clusters and also gives an average internal energy per molecule and radial distribution functions of liquid water in good agreement with experiment. A key to the success of the model is its accurate description of the individual terms in the n-body expansion of the interaction energies.

  6. Building Big Flares: Constraining Generating Processes of Solar Flare Distributions

    NASA Astrophysics Data System (ADS)

    Wyse Jackson, T.; Kashyap, V.; McKillop, S.

    2015-12-01

    We address mechanisms which seek to explain the observed solar flare distribution, dN/dE ~ E1.8. We have compiled a comprehensive database, from GOES, NOAA, XRT, and AIA data, of solar flares and their characteristics, covering the year 2013. These datasets allow us to probe how stored magnetic energy is released over the course of an active region's evolution. We fit power-laws to flare distributions over various attribute groupings. For instance, we compare flares that occur before and after an active region reaches its maximum area, and show that the corresponding flare distributions are indistinguishable; thus, the processes that lead to magnetic reconnection are similar in both cases. A turnover in the distribution is not detectable at the energies accessible to our study, suggesting that a self-organized critical (SOC) process is a valid mechanism. However, we find changes in the distributions that suggest that the simple picture of an SOC where flares draw energy from an inexhaustible reservoir of stored magnetic energy is incomplete. Following the evolution of the flare distribution over the lifetimes of active regions, we find that the distribution flattens with time, and for larger active regions, and that a single power-law model is insufficient. This implies that flares that occur later in the lifetime of the active region tend towards higher energies. We conclude that the SOC process must have an upper bound. Increasing the scope of the study to include data from other years and more instruments will increase the robustness of these results. This work was supported by the NSF-REU Solar Physics Program at SAO, grant number AGS 1263241, NASA Contract NAS8-03060 to the Chandra X-ray Center and by NASA Hinode/XRT contract NNM07AB07C to SAO

  7. Parallel grid generation algorithm for distributed memory computers

    NASA Technical Reports Server (NTRS)

    Moitra, Stuti; Moitra, Anutosh

    1994-01-01

    A parallel grid-generation algorithm and its implementation on the Intel iPSC/860 computer are described. The grid-generation scheme is based on an algebraic formulation of homotopic relations. Methods for utilizing the inherent parallelism of the grid-generation scheme are described, and implementation of multiple levELs of parallelism on multiple instruction multiple data machines are indicated. The algorithm is capable of providing near orthogonality and spacing control at solid boundaries while requiring minimal interprocessor communications. Results obtained on the Intel hypercube for a blended wing-body configuration are used to demonstrate the effectiveness of the algorithm. Fortran implementations bAsed on the native programming model of the iPSC/860 computer and the Express system of software tools are reported. Computational gains in execution time speed-up ratios are given.

  8. Distributed Optimal Generation Control of Shipboard Power Systems

    DTIC Science & Technology

    2012-05-01

    address the needs of SPSs, a fully-distributed, multi - agent system (MAS)-based solution is proposed to optimize the control references of distributed...Transactions on Power Systems, Vol.27, No.1, pp.233-242, Feb. 2012. [4] J. M. Solanki and N. N. Schulz, “Using intelligent multi - agent systems for shipboard...D 2005/2006, pp. 562-567, May 21-24, 2006. [11] J. A. Momoh, K. Alfred and Y. Xia, “Framework for Multi - Agent System (MAS) Detection and Control

  9. Distributed Optimal Generation Control of Shipboard Power Systems

    DTIC Science & Technology

    2012-05-01

    address the needs of SPSs, a fully-distributed, multi - agent system (MAS)-based solution is proposed to optimize the control references of distributed...Systems, Vol.27, No.1, pp.233-242, Feb. 2012. [4] J. M. Solanki and N. N. Schulz, “Using intelligent multi - agent systems for shipboard power...pp. 562-567, May 21-24, 2006. [11] J. A. Momoh, K. Alfred and Y. Xia, “Framework for Multi - Agent System (MAS) Detection and Control of Arcing of

  10. A Concurrent Distributed System for Aircraft Tactical Decision Generation

    NASA Technical Reports Server (NTRS)

    McManus, John W.

    1990-01-01

    A research program investigating the use of artificial intelligence (AI) techniques to aid in the development of a Tactical Decision Generator (TDG) for Within Visual Range (WVR) air combat engagements is discussed. The application of AI programming and problem solving methods in the development and implementation of a concurrent version of the Computerized Logic For Air-to-Air Warfare Simulations (CLAWS) program, a second generation TDG, is presented. Concurrent computing environments and programming approaches are discussed and the design and performance of a prototype concurrent TDG system are presented.

  11. A Test Generation Framework for Distributed Fault-Tolerant Algorithms

    NASA Technical Reports Server (NTRS)

    Goodloe, Alwyn; Bushnell, David; Miner, Paul; Pasareanu, Corina S.

    2009-01-01

    Heavyweight formal methods such as theorem proving have been successfully applied to the analysis of safety critical fault-tolerant systems. Typically, the models and proofs performed during such analysis do not inform the testing process of actual implementations. We propose a framework for generating test vectors from specifications written in the Prototype Verification System (PVS). The methodology uses a translator to produce a Java prototype from a PVS specification. Symbolic (Java) PathFinder is then employed to generate a collection of test cases. A small example is employed to illustrate how the framework can be used in practice.

  12. Distributed Generation Dispatch Optimization under VariousElectricity Tariffs

    SciTech Connect

    Firestone, Ryan; Marnay, Chris

    2007-05-01

    The on-site generation of electricity can offer buildingowners and occupiers financial benefits as well as social benefits suchas reduced grid congestion, improved energy efficiency, and reducedgreenhouse gas emissions. Combined heat and power (CHP), or cogeneration,systems make use of the waste heat from the generator for site heatingneeds. Real-time optimal dispatch of CHP systems is difficult todetermine because of complicated electricity tariffs and uncertainty inCHP equipment availability, energy prices, and system loads. Typically,CHP systems use simple heuristic control strategies. This paper describesa method of determining optimal control in real-time and applies it to alight industrial site in San Diego, California, to examine: 1) the addedbenefit of optimal over heuristic controls, 2) the price elasticity ofthe system, and 3) the site-attributable greenhouse gas emissions, allunder three different tariff structures. Results suggest that heuristiccontrols are adequate under the current tariff structure and relativelyhigh electricity prices, capturing 97 percent of the value of thedistributed generation system. Even more value could be captured bysimply not running the CHP system during times of unusually high naturalgas prices. Under hypothetical real-time pricing of electricity,heuristic controls would capture only 70 percent of the value ofdistributed generation.

  13. Control of dispatch dynamics for lowering the cost of distributed generation in the built environment

    NASA Astrophysics Data System (ADS)

    Flores, Robert Joseph

    Distributed generation can provide many benefits over traditional central generation such as increased reliability and efficiency while reducing emissions. Despite these potential benefits, distributed generation is generally not purchased unless it reduces energy costs. Economic dispatch strategies can be designed such that distributed generation technologies reduce overall facility energy costs. In this thesis, a microturbine generator is dispatched using different economic control strategies, reducing the cost of energy to the facility. Several industrial and commercial facilities are simulated using acquired electrical, heating, and cooling load data. Industrial and commercial utility rate structures are modeled after Southern California Edison and Southern California Gas Company tariffs and used to find energy costs for the simulated buildings and corresponding microturbine dispatch. Using these control strategies, building models, and utility rate models, a parametric study examining various generator characteristics is performed. An economic assessment of the distributed generation is then performed for both the microturbine generator and parametric study. Without the ability to export electricity to the grid, the economic value of distributed generation is limited to reducing the individual costs that make up the cost of energy for a building. Any economic dispatch strategy must be built to reduce these individual costs. While the ability of distributed generation to reduce cost depends of factors such as electrical efficiency and operations and maintenance cost, the building energy demand being serviced has a strong effect on cost reduction. Buildings with low load factors can accept distributed generation with higher operating costs (low electrical efficiency and/or high operations and maintenance cost) due to the value of demand reduction. As load factor increases, lower operating cost generators are desired due to a larger portion of the building load

  14. Development of ozone generator by modification of the field distribution

    NASA Astrophysics Data System (ADS)

    Jenei, I.; Kiss, P.; Kiss, E.

    2008-12-01

    New methods have been established to enhance the ozone production of the surface discharge arrangement. One method sets the discharge electrode a short distance away from the surface of the dielectric material, whilst another uses a special power supply system resulting in a superimposed discharge. According to the experiments, significant differences have been found in the ozone production capacity of the different arrangements. The characteristics of the electric field distribution of the designs have been calculated using the finite element method for the potential; and the Donor-Cell method for the space charge calculation, and the results have been analysed. A method of analysis has been established for the calculated field characteristics, which provides two index numbers. The reasons are highlighted for the differences in ozone production in relation to the index numbers obtained from the fields' distributions of the different arrangements.

  15. Advancements in Distributed Generation Issues: Interconnection, Modeling, and Tariffs

    SciTech Connect

    Thomas, H.; Kroposki, B.; Basso, T.; Treanton, B. G.

    2007-01-01

    The California Energy Commission is cost-sharing research with the Department of Energy through the National Renewable Energy Laboratory to address distributed energy resources (DER) topics. These efforts include developing interconnection and power management technologies, modeling the impacts of interconnecting DER with an area electric power system, and evaluating possible modifications to rate policies and tariffs. As a result, a DER interconnection device has been developed and tested. A workshop reviewed the status and issues of advanced power electronic devices. Software simulations used validated models of distribution circuits that incorporated DER, and tests and measurements of actual circuits with and without DER systems are being conducted to validate these models. Current policies affecting DER were reviewed and rate making policies to support deployment of DER through public utility rates and policies were identified. These advancements are expected to support the continued and expanded use of DER systems.

  16. Combustion intensity and distribution relation to noise generation

    NASA Technical Reports Server (NTRS)

    Plett, E. G.; Leshner, M. D.; Summerfield, M.

    1975-01-01

    Experiments with several different flame holder geometries were conducted to investigate the degree to which combustion roughness can be altered by altering the flame intensity and flame distribution in a ducted combustion system. The effect of admitting primary air through a plane-slotted or a slotted-swirl vane flame holder was compared and the combustion roughness and noise was contrasted with that obtained with a closed front-end perforated can. The slotted front-end burners produced much smoother burning and less noise than the closed front-end can. No advantage was apparent with swirl vs nonswirl when approximately the same inlet flow distribution was maintained. Preheated inlet air provided somewhat smoother combustion as compared with ambient temperature air. The combustion roughness with methyl alcohol was briefly compared with that of isooctane; indications are that it burns more smoothly, but more detailed studies are needed to substantiate these indications.

  17. Generation of Finite Life Distributional Goodman Diagrams for Reliability Prediction

    NASA Technical Reports Server (NTRS)

    Kececioglu, D.; Guerrieri, W. N.

    1971-01-01

    The methodology of developing finite life distributional Goodman diagrams and surfaces is described for presenting allowable combinations of alternating stress and mean stress to the design engineer. The combined stress condition is that of an alternating bending stress and a constant shear stress. The finite life Goodman diagrams and surfaces are created from strength distributions developed at various ratios of alternating to mean stress at particular cycle life values. The conclusions indicate that the Von Mises-Hencky ellipse, for cycle life values above 1000 cycles, is an adequate model of the finite life Goodman diagram. In addition, suggestions are made which reduce the number of experimental data points required in a fatigue data acquisition program.

  18. Distributed Electrical Power Generation: Summary of Alternative Available Technologies

    DTIC Science & Technology

    2003-09-01

    Technical Report (TR)-01-18, ADA388687. Borbely, Ann-Marie and Jan F. Kreider. 2001. Dis ributed Genera on: The Power Paradigm for the New...Construction Engineering Research Laboratory PO Box 9005 Champaign, IL 61826-9005 Final Report Approved for public release; distribution is...are provided. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade

  19. The Value of Distributed Solar Electric Generation to San Antonio

    SciTech Connect

    Jones, Nic; Norris, Ben; Meyer, Lisa

    2013-02-14

    This report presents an analysis of value provided by grid-connected, distributed PV in San Antonio from a utility perspective. The study quantified six value components, summarized in Table ES- 1. These components represent the benefits that accrue to the utility, CPS Energy, in accepting solar onto the grid. This analysis does not treat the compensation of value, policy objectives, or cost-effectiveness from the retail consumer perspective.

  20. Ray tracing for point distribution in unstructured grid generation

    SciTech Connect

    Khamayseh, A.; Ortega, F.; Trease, H.

    1995-12-31

    We present a procedure by which grid points are generated on surfaces or within three-dimensional volumes to produce high quality unstructed grids for complex geometries. The virtue of this method is based on ray-tracing approach for curved polyhedra whose faces may lie on natural quadrics (planes, cylinders, cones, or spheres) or triangular faceted surfaces. We also present an efficient point location algorithm for identifying points relative to various regions with classification of inside/on/outside.

  1. Towards Manufacturing/Distribution Systems in the Next Generation

    NASA Astrophysics Data System (ADS)

    Koshimizu, Hiroyasu; Kaihara, Toshiya; Sawada, Hiroyuki

    Nowadays agile market is in common, and the fundamental technology supporting next-generation production system requires further development of machine and information technologies to establish “human technology” and a bridging of these technologies together. IMS-HUTOP project proposes a new product life cycle that respects the human nature of individuals, and establishes the elemental technologies necessary for acquiring, modelling and evaluating various human factors in an effort to achieve the HUTOP cycle. In this paper we propose a human centred KANSEI manufacturing system, which has been proposed in the IMS-HUTOP project with 5 work packages.

  2. 46 CFR 111.05-17 - Generation and distribution system grounding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... must: (a) Be grounded at the generator switchboard, except the neutral of an emergency power generation... 46 Shipping 4 2010-10-01 2010-10-01 false Generation and distribution system grounding. 111.05-17 Section 111.05-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL...

  3. 46 CFR 111.05-17 - Generation and distribution system grounding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... must: (a) Be grounded at the generator switchboard, except the neutral of an emergency power generation... 46 Shipping 4 2011-10-01 2011-10-01 false Generation and distribution system grounding. 111.05-17 Section 111.05-17 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL...

  4. Pit Distribution Design for Computer-Generated Waveguide Holography

    NASA Astrophysics Data System (ADS)

    Yagi, Shogo; Imai, Tadayuki; Ueno, Masahiro; Ohtani, Yoshimitsu; Endo, Masahiro; Kurokawa, Yoshiaki; Yoshikawa, Hiroshi; Watanabe, Toshifumi; Fukuda, Makoto

    2008-02-01

    Multilayered waveguide holography (MWH) is one of a number of page-oriented data multiplexing holographies that will be applied to optical data storage and three-dimensional (3D) moving images. While conventional volumetric holography using photopolymer or photorefractive materials requires page-by-page light exposure for recording, MWH media can be made by employing stamping and laminating technologies that are suitable for mass production. This makes devising an economical mastering technique for replicating holograms a key issue. In this paper, we discuss an approach to pit distribution design that enables us to replace expensive electron beam mastering with economical laser beam mastering. We propose an algorithm that avoids the overlapping of even comparatively large adjacent pits when we employ laser beam mastering. We also compensate for the angular dependence of the diffraction power, which strongly depends on pit shape, by introducing an enhancement profile so that a diffracted image has uniform intensity.

  5. Generating multipartite entangled states of qubits distributed in different cavities

    NASA Astrophysics Data System (ADS)

    He, Xiao-Ling; Su, Qi-Ping; Zhang, Feng-Yang; Yang, Chui-Ping

    2014-06-01

    Cavity-based large-scale quantum information processing (QIP) needs a large number of qubits, and placing all of them in a single cavity quickly runs into many fundamental and practical problems such as the increase in cavity decay rate and decrease in qubit-cavity coupling strength. Therefore, future QIP most likely will require quantum networks consisting of a large number of cavities, each hosting and coupled to multiple qubits. In this work, we propose a way to prepare a -class entangled state of spatially separated multiple qubits in different cavities, which are connected to a coupler qubit. Because no cavity photon is excited, decoherence caused by the cavity decay is greatly suppressed during the entanglement preparation. This proposal needs only one coupler qubit and one operational step, and does not require using a classical pulse, so that the engineering complexity is much reduced and the operation is greatly simplified. As an example of the experimental implementation, we further give a numerical analysis, which shows that high-fidelity generation of the state using three superconducting phase qubits each embedded in a one-dimensional transmission line resonator is feasible within the present circuit QED technique. The proposal is quite general and can be applied to accomplish the same task with other types of qubits such as superconducting flux qubits, charge qubits, quantum dots, nitrogen-vacancy centers, and atoms.

  6. The Role of Distributed Generation and Combined Heat and Power (CHP) Systems in Data Centers

    EPA Pesticide Factsheets

    This report reviews how distributed generation (DG) resources such as fuel cells, reciprocating engines, and gas turbines can offer powerful energy efficiency savings in data centers, particularly when configured in combined heat and power (CHP) mode.

  7. Multiwavelength generation in a random distributed feedback fiber laser using an all fiber Lyot filter.

    PubMed

    Sugavanam, S; Yan, Z; Kamynin, V; Kurkov, A S; Zhang, L; Churkin, D V

    2014-02-10

    Multiwavelength lasing in the random distributed feedback fiber laser is demonstrated by employing an all fiber Lyot filter. Stable multiwavelength generation is obtained, with each line exhibiting sub-nanometer line-widths. A flat power distribution over multiple lines is obtained, which indicates that the power between lines is redistributed in nonlinear mixing processes. The multiwavelength generation is observed both in first and second Stokes waves.

  8. Distributed Storage Inverter and Legacy Generator Integration Plus Renewable Solution for Microgrids

    DTIC Science & Technology

    2015-07-01

    NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION ...ACKNOWLEDGEMENTS The following organizations and individuals contributed to the success of the “ Distributed Storage Inverter and Legacy Generator Integration

  9. Historical and Current U.S. Strategies for Boosting Distributed Generation

    SciTech Connect

    Lowder, Travis; Schwabe, Paul; Zhou, Ella; Arent, Douglas J.

    2015-10-29

    This report seeks to introduce a variety of top-down and bottom-up practices that, in concert with the macro-environment of cost-reduction globally and early adoption in Europe, helped boost the distributed generation photovoltaic market in the United States. These experiences may serve as a reference in China's quest to promote distributed renewable energy.

  10. Combined Operation of AC and DC Distribution System with Distributed Generation Units

    NASA Astrophysics Data System (ADS)

    Noroozian, Reza; Abedi, Mehrdad; Gharehpetian, Gevorg

    2010-07-01

    This paper presents a DC distribution system which has been supplied by external AC systems as well as local DG units in order to demonstrate an overall solution to power quality issue. In this paper, the proposed operation method is demonstrated by simulation of power transfer between external AC systems, DG units, AC and DC loads. The power flow control in DC distribution system has been achieved by network converters and DG converters. Also, the mathematical model of the network, DG and load converters are obtained by using the average technique, which allows converter systems accurately simulated and control strategies for this converters is achieved. A suitable control strategy for network converters has been proposed that involves DC voltage droop regulator and novel instantaneous power regulation scheme. Also, a novel control technique has been proposed for DG converters. In this paper, a novel control system based on stationary and synchronously rotating reference frame has been proposed for load converters for supplying AC loads connected to the DC bus by balanced voltages. The several case studies have been studied based on proposed methods. The simulation results show that DC distribution systems including DG units can improve the power quality at the point of common coupling (PCC) in the power distribution system or industrial power system.

  11. Technology survey of electrical power generation and distribution for MIUS application

    NASA Technical Reports Server (NTRS)

    Gill, W. L.; Redding, T. E.

    1975-01-01

    Candidate electrical generation power systems for the modular integrated utility systems (MIUS) program are described. Literature surveys were conducted to cover both conventional and exotic generators. Heat-recovery equipment associated with conventional power systems and supporting equipment are also discussed. Typical ranges of operating conditions and generating efficiencies are described. Power distribution is discussed briefly. Those systems that appear to be applicable to MIUS have been indicated, and the criteria for equipment selection are discussed.

  12. Effect of Rayleigh-scattering distributed feedback on multiwavelength Raman fiber laser generation.

    PubMed

    El-Taher, A E; Harper, P; Babin, S A; Churkin, D V; Podivilov, E V; Ania-Castanon, J D; Turitsyn, S K

    2011-01-15

    We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber. Twenty-two lasing lines with spacing of ~100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.

  13. An Effect of Fault Current Limiter to Distributed Generator Shaft Torque Increase under Voltage Sag

    NASA Astrophysics Data System (ADS)

    Tanabe, Takayuki; Funabashi, Toshihisa; Otoguro, Hitomi; Martinez, Juan A.; Putrus, Ghanim; Fujita, Goro; Koyanagi, Kaoru; Yokoyama, Ryuichi

    Voltage sags originated at the transmission level can have a very adverse effect on distributed generators running at distribution levels. A fault current limiter (FCL) can be an effective means to limit the voltage sag impact. This paper presents the main results of a research based on digital simulation and aimed at studying the effectiveness of a FCL to limit the impact of voltage sag on the shaft torque of distributed generators. The sensitivity of the shaft torque to parameters of the FCL, the power system and the fault is analyzed.

  14. Laying the Groundwork: Lessons Learned from the Telecommunications Industry for Distributed Generation; Preprint

    SciTech Connect

    Wise, A. L.

    2008-05-01

    The telecommunications industry went through growing pains in the past that hold some interesting lessons for the growing distributed generation (DG) industry. The technology shifts and stakeholders involved with the historic market transformation of the telecommunications sector mirror similar factors involved in distributed generation today. An examination of these factors may inform best practices when approaching the conduits necessary to accelerate the shifting of our nation's energy system to cleaner forms of generation and use. From a technical perspective, the telecom industry in the 1990s saw a shift from highly centralized systems that had no capacity for adaptation to highly adaptive, distributed network systems. From a management perspective, the industry shifted from small, private-company structures to big, capital-intensive corporations. This presentation will explore potential correlation and outline the lessons that we can take away from this comparison.

  15. Future Impacts of Distributed Power Generation on Ambient Ozone and Particulate Matter Concentrations in the San Joaquin Valley of California.

    PubMed

    Vutukuru, Satish; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald

    2011-12-01

    Distributed power generation-electricity generation that is produced by many small stationary power generators distributed throughout an urban air basin-has the potential to supply a significant portion of electricity in future years. As a result, distributed generation may lead to increased pollutant emissions within an urban air basin, which could adversely affect air quality. However, the use of combined heating and power with distributed generation may reduce the energy consumption for space heating and air conditioning, resulting in a net decrease of pollutant and greenhouse gas emissions. This work used a systematic approach based on land-use geographical information system data to determine the spatial and temporal distribution of distributed generation emissions in the San Joaquin Valley Air Basin of California and simulated the potential air quality impacts using state-of-the-art three-dimensional computer models. The evaluation of the potential market penetration of distributed generation focuses on the year 2023. In general, the air quality impacts of distributed generation were found to be small due to the restrictive 2007 California Air Resources Board air emission standards applied to all distributed generation units and due to the use of combined heating and power. Results suggest that if distributed generation units were allowed to emit at the current Best Available Control Technology standards (which are less restrictive than the 2007 California Air Resources Board standards), air quality impacts of distributed generation could compromise compliance with the federal 8-hr average ozone standard in the region. [Box: see text].

  16. Future impacts of distributed power generation on ambient ozone and particulate matter concentrations in the San Joaquin Valley of California.

    PubMed

    Vutukuru, Satish; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald

    2011-12-01

    Distributed power generation-electricity generation that is produced by many small stationary power generators distributed throughout an urban air basin-has the potential to supply a significant portion of electricity in future years. As a result, distributed generation may lead to increased pollutant emissions within an urban air basin, which could adversely affect air quality. However, the use of combined heating and power with distributed generation may reduce the energy consumption for space heating and air conditioning, resulting in a net decrease of pollutant and greenhouse gas emissions. This work used a systematic approach based on land-use geographical information system data to determine the spatial and temporal distribution of distributed generation emissions in the San Joaquin Valley Air Basin of California and simulated the potential air quality impacts using state-of-the-art three-dimensional computer models. The evaluation of the potential market penetration of distributed generation focuses on the year 2023. In general, the air quality impacts of distributed generation were found to be small due to the restrictive 2007 California Air Resources Board air emission standards applied to all distributed generation units and due to the use of combined heating and power. Results suggest that if distributed generation units were allowed to emit at the current Best Available Control Technology standards (which are less restrictive than the 2007 California Air Resources Board standards), air quality impacts of distributed generation could compromise compliance with the federal 8-hr average ozone standard in the region.

  17. A Study on the Installation Promotion Program of Distributed Generation with Load Curtailment Contract

    NASA Astrophysics Data System (ADS)

    Sasaki, Yutaka; Hara, Ryoichi; Kita, Hiroyuki; Hasegawa, Jun

    Distribution generation using new energy resources have been expected in the future power system. However, the interconnection cost and equipment cost of distributed generation (DG) are still expensive and stunt the growth of installed DG capacity. From the economic and environmental points of view, promotion of DG installation is indispensable in the future. This paper proposes a DG installation promotion program based on the load curtailment contract. In the proposed program, the load curtailment contract saves investments required for future power system reinforcement and induces the customers to install DG. Economical and environmental feasibility of the proposed program are discussed through numerical studies.

  18. An efficient algorithm for generating random number pairs drawn from a bivariate normal distribution

    NASA Technical Reports Server (NTRS)

    Campbell, C. W.

    1983-01-01

    An efficient algorithm for generating random number pairs from a bivariate normal distribution was developed. Any desired value of the two means, two standard deviations, and correlation coefficient can be selected. Theoretically the technique is exact and in practice its accuracy is limited only by the quality of the uniform distribution random number generator, inaccuracies in computer function evaluation, and arithmetic. A FORTRAN routine was written to check the algorithm and good accuracy was obtained. Some small errors in the correlation coefficient were observed to vary in a surprisingly regular manner. A simple model was developed which explained the qualities aspects of the errors.

  19. Historical and Current U.S. Strategies for Boosting Distributed Generation (Chinese Translation)

    SciTech Connect

    Lowder, Travis; Schwabe, Paul; Zhou, Ella; Arent, Douglas J.

    2015-08-01

    This is the Chinese translation of NREL/TP-6A20-64843. This report seeks to introduce a variety of top-down and bottom-up practices that, in concert with the macro-environment of cost-reduction globally and early adoption in Europe, helped boost the distributed generation photovoltaic market in the United States. These experiences may serve as a reference in China's quest to promote distributed renewable energy.

  20. Distributed Generation Planning using Peer Enhanced Multi-objective Teaching-Learning based Optimization in Distribution Networks

    NASA Astrophysics Data System (ADS)

    Selvam, Kayalvizhi; Vinod Kumar, D. M.; Siripuram, Ramakanth

    2016-06-01

    In this paper, an optimization technique called peer enhanced teaching learning based optimization (PeTLBO) algorithm is used in multi-objective problem domain. The PeTLBO algorithm is parameter less so it reduced the computational burden. The proposed peer enhanced multi-objective based TLBO (PeMOTLBO) algorithm has been utilized to find a set of non-dominated optimal solutions [distributed generation (DG) location and sizing in distribution network]. The objectives considered are: real power loss and the voltage deviation subjected to voltage limits and maximum penetration level of DG in distribution network. Since the DG considered is capable of injecting real and reactive power to the distribution network the power factor is considered as 0.85 lead. The proposed peer enhanced multi-objective optimization technique provides different trade-off solutions in order to find the best compromise solution a fuzzy set theory approach has been used. The effectiveness of this proposed PeMOTLBO is tested on IEEE 33-bus and Indian 85-bus distribution system. The performance is validated with Pareto fronts and two performance metrics (C-metric and S-metric) by comparing with robust multi-objective technique called non-dominated sorting genetic algorithm-II and also with the basic TLBO.

  1. THE COLD SHOULDER: EMISSION MEASURE DISTRIBUTIONS OF ACTIVE REGION CORES

    SciTech Connect

    Schmelz, J. T.; Pathak, S.

    2012-09-10

    The coronal heating mechanism for active region core loops is difficult to determine because these loops are often not resolved and cannot be studied individually. Rather, we concentrate on the 'inter-moss' areas between loop footpoints. We use observations from the Hinode EUV Imaging Spectrometer and the X-Ray Telescope to calculate the emission measure distributions of eight inter-moss areas in five different active regions. The combined data sets provide both high- and low-temperature constraints and ensure complete coverage in the temperature range appropriate for active regions. For AR 11113, the emission can be modeled with heating events that occur on timescales less than the cooling time. The loops in the core regions appear to be close to equilibrium and are consistent with steady heating. The other regions studied, however, appear to be dominated by nanoflare heating. Our results are consistent with the idea that active region age is an important parameter in determining whether steady or nanoflare heating is primarily responsible for the core emission, that is, older regions are more likely to be dominated by steady heating, while younger regions show more evidence of nanoflares.

  2. A stochastic basis to the spatially uniform distribution of randomly generated Ionian paterae

    NASA Astrophysics Data System (ADS)

    Shoji, D.; Hussmann, H.

    2016-10-01

    Due to its tidally heated interior, Io is a geologically very active satellite that bears many volcanic features. It is observed that the mean nearest neighbor distance of each volcanic feature, called a patera, is larger than that of a random distribution, which implies that the spatial distribution of paterae is uniform rather than random. However, it is uncertain how the paterae are organized into a uniform distribution. We suggest the mechanism of Io's uniformly distributed paterae considering localized obliteration of old features. Instead of geological modeling, we performed stochastic simulations and statistical analyses for the obliteration of quiescent paterae. Monte Carlo calculations with Gaussian obliteration probability show that if the width of obliteration probability is approximately 80 km and the volcanic generation rate is ˜5.0 × 10-6 km-2 Ma-1, uniform distribution and the observed number density of paterae are attained at the 2σ level on a time scale of approximately 6 Myr. With this generation rate and width of the obliteration probability, the averaged distance of one patera to the nearest patera (mean nearest neighbor distance) is approximately 200 km, which is consistent with the observed value. The uniformity of the distribution is maintained once it is achieved. On regional scales, Io's paterae would naturally evolve from random into uniform distributions by the obliteration of old and quiescent features.

  3. Temperature Analysis of Coronal Loop Cross-Sections: Monolithic vs. Nanoflare Heating

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.; Boerner, P.

    2011-05-01

    We present a first systematic study on the cross-sectional temperature structure of coronal loops using the six coronal temperature filters of the Atmospheric Imaging Assembly (AIA) instrument on the Solar Dynamics Observatory (SDO). We analyze a sample of 100 loop snapshots measured at 10 different locations and 10 different times in active region NOAA 11089 on 2010 July 24, 21:00-22:00 UT. The cross-sectional flux profiles are measured and a cospatial background is subtracted in 6 filters in a temperature range of T ≈ 0.5-16 MK, and 4 different parameterizations of differential emission measure (DEM) distributions are fitted. We find that the reconstructed DEMs consist predominantly of narrowband peak temperature components with a thermal width of σlog(T) ≤ 0.11±0.02, close to the temperature resolution limit of the instrument, consistent with earlier triple-filter analysis from TRACE by Aschwanden and Nightingale (2005) and from EIS/Hinode by Warren et al. (2008) or Tripathi et al. (2009). We find that 66% of the loops could be fitted with a narrowband single-Gaussian DEM model, and 19% with a DEM consisting of two narrowband Gaussians (which mostly result from pairs of intersecting loops along the same line-of-sight). The mostly isothermal loop DEMs allow us also to derive an improved empirical response function of the AIA 94 [[Unable to Display Character: Ǻ

  4. On the angular and energy distribution of solar neutrons generated in P-P reactions

    NASA Technical Reports Server (NTRS)

    Efimov, Y. E.; Kocharov, G. E.

    1985-01-01

    The problem of high energy neutron generation in P-P reactions in the solar atmosphere is reconsidered. It is shown that the angular distribution of emitted neutrons is anisotropic and the energy spectrum of neutrons depends on the angle of neutron emission.

  5. Distributed state-space generation of discrete-state stochastic models

    NASA Technical Reports Server (NTRS)

    Ciardo, Gianfranco; Gluckman, Joshua; Nicol, David

    1995-01-01

    High-level formalisms such as stochastic Petri nets can be used to model complex systems. Analysis of logical and numerical properties of these models of ten requires the generation and storage of the entire underlying state space. This imposes practical limitations on the types of systems which can be modeled. Because of the vast amount of memory consumed, we investigate distributed algorithms for the generation of state space graphs. The distributed construction allows us to take advantage of the combined memory readily available on a network of workstations. The key technical problem is to find effective methods for on-the-fly partitioning, so that the state space is evenly distributed among processors. In this paper we report on the implementation of a distributed state-space generator that may be linked to a number of existing system modeling tools. We discuss partitioning strategies in the context of Petri net models, and report on performance observed on a network of workstations, as well as on a distributed memory multi-computer.

  6. Study on Voltage Regulation Methods for Distribution Systems with Dispersed Generators

    NASA Astrophysics Data System (ADS)

    Kondoh, Junji; Aki, Hirohisa; Yamaguchi, Hiroshi; Murata, Akinobu; Ishii, Itaru

    Connection of a large number of the dispersed generators to distribution networks is not easy due to various technical considerations. Thus we have been trying to devise a concept for future electrical distribution systems with a lot of dispersed generators. In this work, it has been considered that each customer’s load and each generator’s active and reactive power should be controlled in order to stabilize and optimize the networks. Under this consideration, two control methods for future distribution systems are proposed, a cooperative control and an independent control. We have confirmed experimentally that the voltage regulation ability is higher with the cooperative control than with the independent control, especially in the cases of an eccentric load profile in a feeder and a heavy load.

  7. Power-law Distributions of Offspring and Generation Numbers in Branching Models of Earthquake Triggering

    NASA Astrophysics Data System (ADS)

    Saichev, A.; Helmstetter, A.; Sornette, D.

    2005-06-01

    We consider a general stochastic branching process,which is relevant to earthquakes as well as to many other systems, and we study the distributions of the total number of offsprings (direct and indirect aftershocks in seismicity) and of the total number of generations before extinction. We apply our results to a branching model of triggered seismicity, the ETAS (epidemic-type aftershock sequence) model. The ETAS model assumes that each earthquake can trigger other earthquakes (“aftershocks”). An aftershock sequence results in this model from the cascade of aftershocks of each past earthquake. Due to the large fluctuations of the number of aftershocks triggered directly by any earthquake (“fertility”), there is a large variability of the total number of aftershocks from one sequence to another, for the same mainshock magnitude. We study the regime in which the distribution of fertilities μ is characterized by a power law ~1/μ1+γ. For earthquakes we expect such a power-distribution of fertilities with γ=b/α based on the Gutenberg-Richter magnitude distribution ~ 10-bm and on the increase ~ 10-αm of the number of aftershocks with the mainshock magnitude m. We derive the asymptotic distributions pr(r) and pg(g) of the total number r of offsprings and of the total number g of generations until extinction following a mainshock. In the regime γ < 2 for which the distribution of fertilities has an infinite variance, we find This should be compared with the distributions obtained for standard branching processes with finite variance. These predictions are checked by numerical simulations. Our results apply directly to the ETAS model whose preferred values α=0.8 1 and b=1 puts it in the regime where the distribution of fertilities has an infinite variance. More generally, our results apply to any stochastic branching process with a power-law distribution of offsprings per mother

  8. Cooperative Allocation of SVR and SVC for Voltage Fluctuation in Case of Connecting Distributed Generators

    NASA Astrophysics Data System (ADS)

    Sugimoto, Junjiro; Yokoyama, Ryuichi; Fujita, Goro; Fukuyama, Yoshikazu

    This paper presents a cooperative allocation method of Step Voltage Regulators (SVRs) and Static Var Compensators (SVCs) in case where some distributed generators (DGs) are installed in distribution systems. In the proposed method, the reactive tabu search (RTS) with multiple structures and functions has been applied. Firstly, the allocations of SVRs are selected optimally and secondly the tap positions of SVRs are optimized by the RTS. Finally, the locations of SVC are decided to brush up the voltage profile in the distribution network. The proposed method enables us to take account of the installation cost of both SVR and SVC as an economic criterion, the upper and lower limit of voltage at each node, and also the upper limit of line currents as constraints. By applying the proposed method to a practical distribution test system (IEEE 34 Node Test Feeder Model), it is verified that this method is efficient in allocating SVRs and SVCs at the minimum cost and to regulating the system voltages within an appropriate value after introducing distributed generators into the distribution system.

  9. Autonomous Decentralized Control of Supply and Demand by Inverter Based Distributed Generations in Isolated Microgrid

    NASA Astrophysics Data System (ADS)

    Shiki, Akira; Yokoyama, Akihiko; Baba, Jyunpei; Takano, Tomihiro; Gouda, Takahiro; Izui, Yoshio

    Recently, because of the environmental burden mitigation, energy conservations, energy security, and cost reductions, distributed generations are attracting our strong attention. These distributed generations (DGs) have been already installed to the distribution system, and much more DGs will be expected to be connected in the future. On the other hand, a new concept called “Microgrid” which is a small power supply network consisting of only DGs was proposed and some prototype projects are ongoing in Japan. The purpose of this paper is to develop the three-phase instantaneous valued digital simulator of microgrid consisting of a lot of inverter based DGs and to develop a supply and demand control method in isolated microgrid. First, microgrid is modeled using MATLAB/SIMULINK. We develop models of three-phase instantaneous valued inverter type CVCF generator, PQ specified generator, PV specified generator, PQ specified load as storage battery, photovoltaic generation, fuel cell and inverter load respectively. Then we propose an autonomous decentralized control method of supply and demand in isolated microgrid where storage batteries, fuel cells, photovoltaic generations and loads are connected. It is proposed here that the system frequency is used as a means to control DG output. By changing the frequency of the storage battery due to unbalance of supply and demand, all inverter based DGs detect the frequency fluctuation and change their own outputs. Finally, a new frequency control method in autonomous decentralized control of supply and demand is proposed. Though the frequency is used to transmit the information on the supply and demand unbalance to DGs, after the frequency plays the role, the frequency finally has to return to a standard value. To return the frequency to the standard value, the characteristic curve of the fuel cell is shifted in parallel. This control is carried out corresponding to the fluctuation of the load. The simulation shows that the

  10. Automatic generation of efficient array redistribution routines for distributed memory multicomputers

    NASA Technical Reports Server (NTRS)

    Ramaswamy, Shankar; Banerjee, Prithviraj

    1994-01-01

    Appropriate data distribution has been found to be critical for obtaining good performance on Distributed Memory Multicomputers like the CM-5, Intel Paragon and IBM SP-1. It has also been found that some programs need to change their distributions during execution for better performance (redistribution). This work focuses on automatically generating efficient routines for redistribution. We present a new mathematical representation for regular distributions called PITFALLS and then discuss algorithms for redistribution based on this representation. One of the significant contributions of this work is being able to handle arbitrary source and target processor sets while performing redistribution. Another important contribution is the ability to handle an arbitrary number of dimensions for the array involved in the redistribution in a scalable manner. Our implementation of these techniques is based on an MPI-like communication library. The results presented show the low overheads for our redistribution algorithm as compared to naive runtime methods.

  11. Research on solving the optimal sizing and siting of distributed generation

    NASA Astrophysics Data System (ADS)

    Wang, Bo

    2017-01-01

    In this paper, a distributed network planning model is proposed with the goal of minimizing the sum of distributed power investment cost, network loss and interruption cost. In order to compare the performance of differential evolution algorithm (DE) and genetic algorithm (GA) in solving the optimal sizing and siting of distributed generation in distribution networks, the two algorithms were adopted to optimize the capacities and positions of DGs. Through analysis on a 10-bus test system, the study results show that the proposed model and algorithm can get reasonable planning scheme. And in solving simple optimization problems, both GA and DE Algorithms can get good results, but compare to DE, GA is of slow convergence speed and the convergence process is not quite stable.

  12. Modeling the Impacts of Solar Distributed Generation on U.S. Water Resources

    SciTech Connect

    Amanda, Smith; Omitaomu, Olufemi A; Jaron, Peck

    2015-01-01

    Distributed electric power generation technologies typically use little or no water per unit of electrical energy produced; in particular, renewable energy sources such as solar PV systems do not require cooling systems and present an opportunity to reduce water usage for power generation. Within the US, the fuel mix used for power generation varies regionally, and certain areas use more water for power generation than others. The need to reduce water usage for power generation is even more urgent in view of climate change uncertainties. In this paper, we present an example case within the state of Tennessee, one of the top four states in water consumption for power generation and one of the states with little or no potential for developing centralized renewable energy generations. The potential for developing PV generation within Knox County, Tennessee, is studied, along with the potential for reducing water withdrawal and consumption within the Tennessee Valley stream region. Electric power generation plants in the region are quantified for their electricity production and expected water withdrawal and consumption over one year, where electrical generation data is provided over one year and water usage is modeled based on the cooling system(s) in use. Potential solar PV electrical production is modeled based on LiDAR data and weather data for the same year. Our proposed methodology can be summarized as follows: First, the potential solar generation is compared against the local grid demand. Next, electrical generation reductions are specified that would result in a given reduction in water withdrawal and a given reduction in water consumption, and compared with the current water withdrawal and consumption rates for the existing fuel mix. The increase in solar PV development that would produce an equivalent amount of power, is determined. In this way, we consider how targeted local actions may affect the larger stream region through thoughtful energy development

  13. A formalism to generate probability distributions for performance-assessment modeling

    SciTech Connect

    Kaplan, P.G.

    1990-12-31

    A formalism is presented for generating probability distributions of parameters used in performance-assessment modeling. The formalism is used when data are either sparse or nonexistent. The appropriate distribution is a function of the known or estimated constraints and is chosen to maximize a quantity known as Shannon`s informational entropy. The formalism is applied to a parameter used in performance-assessment modeling. The functional form of the model that defines the parameter, data from the actual field site, and natural analog data are analyzed to estimate the constraints. A beta probability distribution of the example parameter is generated after finding four constraints. As an example of how the formalism is applied to the site characterization studies of Yucca Mountain, the distribution is generated for an input parameter in a performance-assessment model currently used to estimate compliance with disposal of high-level radioactive waste in geologic repositories, 10 CFR 60.113(a)(2), commonly known as the ground water travel time criterion. 8 refs., 2 figs.

  14. Thermodynamic method for generating random stress distributions on an earthquake fault

    USGS Publications Warehouse

    Barall, Michael; Harris, Ruth A.

    2012-01-01

    This report presents a new method for generating random stress distributions on an earthquake fault, suitable for use as initial conditions in a dynamic rupture simulation. The method employs concepts from thermodynamics and statistical mechanics. A pattern of fault slip is considered to be analogous to a micro-state of a thermodynamic system. The energy of the micro-state is taken to be the elastic energy stored in the surrounding medium. Then, the Boltzmann distribution gives the probability of a given pattern of fault slip and stress. We show how to decompose the system into independent degrees of freedom, which makes it computationally feasible to select a random state. However, due to the equipartition theorem, straightforward application of the Boltzmann distribution leads to a divergence which predicts infinite stress. To avoid equipartition, we show that the finite strength of the fault acts to restrict the possible states of the system. By analyzing a set of earthquake scaling relations, we derive a new formula for the expected power spectral density of the stress distribution, which allows us to construct a computer algorithm free of infinities. We then present a new technique for controlling the extent of the rupture by generating a random stress distribution thousands of times larger than the fault surface, and selecting a portion which, by chance, has a positive stress perturbation of the desired size. Finally, we present a new two-stage nucleation method that combines a small zone of forced rupture with a larger zone of reduced fracture energy.

  15. Generation and Distribution of a Magnetic Field in Superconducting Strange Stars

    NASA Astrophysics Data System (ADS)

    Sedrakian, D. M.; Hayrapetyan, M. V.; Baghdasaryan, D. S.

    2015-12-01

    Generation of a magnetic field and its distribution are considered within a rotating strange quark star with a crust. It is shown how, over time, a differential rotation is established between the superfluid and superconducting quark core and normal electron plasma, which leads to the generation of magnetic field. The magnetic field at the surface of a strange star may attain values of 1011-1015 G, depending on the star model. It is suggested that magnetars may be manifestations of strange stars, the cores of which rotate much faster than the observable part, i.e., the crust.

  16. Probing molecular frame photoelectron angular distributions via high-order harmonic generation from aligned molecules

    NASA Astrophysics Data System (ADS)

    Lin, C. D.; Jin, Cheng; Le, Anh-Thu; Lucchese, R. R.

    2012-10-01

    We analyse the theory of single photoionization (PI) and high-order harmonic generation (HHG) by intense lasers from aligned molecules. We show that molecular-frame photoelectron angular distributions can be extracted from these measurements. We also show that, under favourable conditions, the phase of PI transition dipole matrix elements can be extracted from the HHG spectra. Furthermore, by varying the polarization axis of the HHG generating laser with respect to the polarization axis of the aligning laser, it is possible to extract angle-dependent tunnelling ionization rates for different subshells of the molecules.

  17. Generation and evolution of magnetic field in the relativistic plasma following q-nonextensive distribution

    NASA Astrophysics Data System (ADS)

    Lin, Fu-Jun; Chen, Zong-Hua; Li, Xiao-Qing; Liao, Jing-Jing; Zhu, Yun

    2017-02-01

    A GigaGauss quasi-steady magnetic field can be generated in astrophysical plasmas and laser-produced plasmas with high-frequency electromagnetic radiation through wave-wave and wave-particle interactions. A set of governing equations for this field are obtained in the plasma consisting of ultra-relativistic electrons following q-nonextensive distribution. The numerical results show that the initial field is unstable and can collapse to generate various spatially intermittent magnetic flux tubes. It can also be found that the behavior of the magnetic field is greatly dependent on the nonextensive index q, which may be helpful in understanding the magnetic turbulence.

  18. A Practical Method for Assessing the Effectiveness of Vector Surge Relays for Distributed Generation Applications

    SciTech Connect

    Freitas, Walmir; Huang, Zhenyu; Xu, Wilsun

    2005-01-01

    This paper presents simple and reliable method for predicting the islanding detection performance of vector surge relays. The relay performance is characterized by a tripping-time versus power-imbalance curve. With the curve, one can determine the time taken by a vector surge relay to detect islanding for any generation-load mismatch level. The main contribution of this paper is the development of analytical formulas for directly determining the behavior of vector surge relays. As a result, efforts needed to asses the relay performance for a given distributed generation scheme can be simplified significantly. The accuracy of the formulas has been verified by extensive simulation study results.

  19. [Comparative studies of particle distribution range of aerosol cromolyn sodium generated by MDI systems].

    PubMed

    Gradoń, L; Sosnowski, T R

    1999-05-01

    Particles size distribution of the sodium cromoglycate preparations: CROPOZ PLUS and CROMOGEN EB generated with MDI and for under-pressure releasing methods were measured. Results of measurements indicate a significant repeatability of each sample properties. An average contribution of mass of the respirable fraction for both aerosolized pharmaceuticals is in the range of 40% of the generated dose. CROMOGEN EB with optimizer (spacer) gives a higher contribution of the respirable fraction--up to 50% of dose, with simultaneous lower value of the released mass of aerosol. Particles size distribution of CROPOZ PLUS within a respirable fraction indicates an efficient penetration and deposition of particles in the upper, central and peripheral parts of tracheobronchial tree (TB). High contribution of submicron particles of CROMOGEN EB with optimizer gives efficient penetration and deposition of these particles in the lungs.

  20. Distributed source model for the full-wave electromagnetic simulation of nonlinear terahertz generation.

    PubMed

    Fumeaux, Christophe; Lin, Hungyen; Serita, Kazunori; Withayachumnankul, Withawat; Kaufmann, Thomas; Tonouchi, Masayoshi; Abbott, Derek

    2012-07-30

    The process of terahertz generation through optical rectification in a nonlinear crystal is modeled using discretized equivalent current sources. The equivalent terahertz sources are distributed in the active volume and computed based on a separately modeled near-infrared pump beam. This approach can be used to define an appropriate excitation for full-wave electromagnetic numerical simulations of the generated terahertz radiation. This enables predictive modeling of the near-field interactions of the terahertz beam with micro-structured samples, e.g. in a near-field time-resolved microscopy system. The distributed source model is described in detail, and an implementation in a particular full-wave simulation tool is presented. The numerical results are then validated through a series of measurements on square apertures. The general principle can be applied to other nonlinear processes with possible implementation in any full-wave numerical electromagnetic solver.

  1. Cryptographically secure hardware random number generator dedicated for distributed measurement and control systems

    NASA Astrophysics Data System (ADS)

    Czernik, Pawel

    The chaotic signal generator based on the theory of nonlinear dynamical systems for applications in cryptographically secure distributed measurement and control systems with asymmetric resources is presented. This system was implemented on the basis of the physical chaotic electronic vibration generator in which the resonant circuit is composed of two capacitors, two resistors, coil and transistor, called the Colpitts oscillator. The presented system was designed, programmed and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. True cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results will be here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.

  2. Ionic Liquids for Utilization of Waste Heat from Distributed Power Generation Systems

    SciTech Connect

    Joan F. Brennecke; Mihir Sen; Edward J. Maginn; Samuel Paolucci; Mark A. Stadtherr; Peter T. Disser; Mike Zdyb

    2009-01-11

    The objective of this research project was the development of ionic liquids to capture and utilize waste heat from distributed power generation systems. Ionic Liquids (ILs) are organic salts that are liquid at room temperature and they have the potential to make fundamental and far-reaching changes in the way we use energy. In particular, the focus of this project was fundamental research on the potential use of IL/CO2 mixtures in absorption-refrigeration systems. Such systems can provide cooling by utilizing waste heat from various sources, including distributed power generation. The basic objectives of the research were to design and synthesize ILs appropriate for the task, to measure and model thermophysical properties and phase behavior of ILs and IL/CO2 mixtures, and to model the performance of IL/CO2 absorption-refrigeration systems.

  3. Generating Correlated, Non-normally Distributed Data Using a Non-linear Structural Model.

    PubMed

    Auerswald, Max; Moshagen, Morten

    2015-12-01

    An approach to generate non-normality in multivariate data based on a structural model with normally distributed latent variables is presented. The key idea is to create non-normality in the manifest variables by applying non-linear linking functions to the latent part, the error part, or both. The algorithm corrects the covariance matrix for the applied function by approximating the deviance using an approximated normal variable. We show that the root mean square error (RMSE) for the covariance matrix converges to zero as sample size increases and closely approximates the RMSE as obtained when generating normally distributed variables. Our algorithm creates non-normality affecting every moment, is computationally undemanding, easy to apply, and particularly useful for simulation studies in structural equation modeling.

  4. Optimal pair-generation rate for entanglement-based quantum key distribution

    NASA Astrophysics Data System (ADS)

    Holloway, Catherine; Doucette, John A.; Erven, Christopher; Bourgoin, Jean-Philippe; Jennewein, Thomas

    2013-02-01

    In entanglement-based quantum key distribution (QKD), the generation and detection of multiphoton modes leads to a trade-off between entanglement visibility and twofold coincidence events when maximizing the secure key rate. We produce a predictive model for the optimal twofold coincidence probability per coincidence window given the channel efficiency and detector dark count rate of a given system. This model is experimentally validated and used in simulations for QKD with satellites as well as optical fibers.

  5. An experimental study of the surface elevation probability distribution and statistics of wind-generated waves

    NASA Technical Reports Server (NTRS)

    Huang, N. E.; Long, S. R.

    1980-01-01

    Laboratory experiments were performed to measure the surface elevation probability density function and associated statistical properties for a wind-generated wave field. The laboratory data along with some limited field data were compared. The statistical properties of the surface elevation were processed for comparison with the results derived from the Longuet-Higgins (1963) theory. It is found that, even for the highly non-Gaussian cases, the distribution function proposed by Longuet-Higgins still gives good approximations.

  6. Storm-Generated Sediment Distribution Along the Northwest Florida Inner Continental Shelf

    DTIC Science & Technology

    2009-10-04

    into our study area. Although radiocarbon dating and faunal assemblage analyses were not conducted, the vibracore samples likely did not pene- trate...currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) 04-10-2009 2. REPORT...TYPE Journal Article 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Storm-Generated Sediment Distribution along the Northwest Florida Inner

  7. Mapping PET-measured triamcinolone acetonide (TAA) aerosol distribution into deposition by airway generation.

    PubMed

    Lee, Z; Berridge, M S; Finlay, W H; Heald, D L

    2000-04-10

    The three dimensional (3D) distribution of inhaled drugs was measured using Positron Emission Tomography (PET) (Berridge, M.S, Muswick, G.J., Lee, Z., Leisure, G.L., Nelson, A.D., Muzic, R.F. Jr., Miraldi, F., Heald, D.L., 1997. PET evaluation of Azmacort(R) ([C-11]triamcinolone acetonide) dose administration. J. Nucl. Med. 38 (5) Suppl., 4-5). Data analysis was based upon regional ratios or penetration indices. To improve the analytical usefulness and objectivity, labeled drug from dynamic PET images was mapped into 23 airway generations following a general framework from a SPECT-based methodology (Fleming, J.S., Nassim, M.A., Hashish, A.H., Bailey, A.G. , Conway, J., Holgate, S., Halson, P., Moore, E., Martonen, T.B., 1995. Description of pulmonary deposition of radiolabeled aerosol by airway generation using a conceptual three dimensional model of lung morphology. J. Aerosol Med. 8, 341-356). A recently developed airway network model was used in this study. Quantitative PET scans of [C-11]triamcinolone acetonide distribution in the lung were determined following administration of Azmacort(R), a commercial metered dose inhaler with an integrated spacer device. Distributions at varying time periods after drug administration were investigated to explore the dynamics and kinetics of the aerosolized drug. Initially, deposition of labeled drug on conducting airways (generations 1-14) was found to be higher than those on acinar airways (generation 15-23), 64% versus 36%. The distribution pattern changed slowly with time. By 47 min, 51% of the dose remaining in the lung was found on conducting airways while 49% was on acinar airways. This study illustrates the value of PET imaging for the evaluation and design of drug formulations.

  8. Effects on electrical distribution networks of dispersed power generation at high levels of connection penetration

    SciTech Connect

    Longrigg, P

    1983-07-01

    The advent and deployment of significant levels of photovoltaic and wind energy generation in the spatially dispersed mode (i.e., residential and intermediate load centers) may have deleterious effects upon existing protective relay equipment and its time-current coordination on radial distribution circuits to which power conditioning equipment may be connected for power sell-back purposes. The problems that may arise involve harmonic injection from power conditioning inverters that can affect protective relays and cause excessive voltage and current from induced series and parallel resonances on feeders and connected passive equipment. Voltage regulation, var requirements, and consumer metering can also be affected by this type of dispersed generation. The creation of islands of supply is also possible, particularly on rural supply systems. This paper deals mainly with the effects of harmonics and short-circuit currents from wind energy conversion systems (WECS) and photovoltaic (PV) systems upon the operating characteristics of distribution networks and relays and other protective equipment designed to ensure the safety and supply integrity of electrical utility networks. Traditionally, electrical supply networks have been designed for one-way power flow-from generation to load, with a balance maintained between the two by means of automatic generation and load-frequency controls. Dispersed generation, from renewables like WECS or PV or from nonrenewable resources, can change traditional power flow. These changes must be dealt with effectively if renewable energy resources are to be integrated into the utility distribution system. This paper gives insight into these problems and proposes some solutions.

  9. Limits and Economic Effects of Distributed PV Generation in North and South Carolina

    NASA Astrophysics Data System (ADS)

    Holt, Kyra Moore

    The variability of renewable sources, such as wind and solar, when integrated into the electrical system must be compensated by traditional generation sources in-order to maintain the constant balance of supply and demand required for grid stability. The goal of this study is to analyze the effects of increasing large levels of solar Photovoltaic (PV) penetration (in terms of a percentage of annual energy production) on a test grid with similar characteristics to the Duke Energy Carolinas (DEC) and Progress Energy Carolinas (PEC) regions of North and South Carolina. PV production is modeled entering the system at the distribution level and regional PV capacity is based on household density. A gridded hourly global horizontal irradiance (GHI) dataset is used to capture the variable nature of PV generation. A unit commitment model (UCM) is then used determine the hourly dispatch of generators based on generator parameters and costs to supply generation to meet demand. Annual modeled results for six different scenarios are evaluated to determine technical, environmental and economic effects of varying levels of distributed PV penetration on the system. This study finds that the main limiting factor for PV integration in the DEC and PEC balancing authority regions is defined by the large generating capacity of base-load nuclear plants within the system. This threshold starts to affect system stability at integration levels of 5.7%. System errors, defined by imbalances caused by over or under generation with respect to demand, are identified in the model however the validity of these errors in real world context needs further examination due to the lack of high frequency irradiance data and modeling limitations. Operational system costs decreased as expected with PV integration although further research is needed to explore the impacts of the capital costs required to achieve the penetration levels found in this study. PV system generation was found to mainly displace

  10. Distributed gain in plasmonic reflectors and its use for terahertz generation.

    PubMed

    Sydoruk, O; Syms, R R A; Solymar, L

    2012-08-27

    Semiconductor plasmons have potential for terahertz generation. Because practical device formats may be quasi-optical, we studied theoretically distributed plasmonic reflectors that comprise multiple interfaces between cascaded two-dimensional electron channels. Employing a mode-matching technique, we show that transmission through and reflection from a single interface depend on the magnitude and direction of a dc current flowing in the channels. As a result, plasmons can be amplified at an interface, and the cumulative effect of multiple interfaces increases the total gain, leading to plasmonic reflection coefficients exceeding unity. Reversing the current direction in a distributed reflector, however, has the opposite effect of plasmonic deamplification. Consequently, we propose structurally asymmetric resonators comprising two different distributed reflectors and predict that they are capable of terahertz oscillations at low threshold currents.

  11. Performance of marine power plant given generator, main and distribution switchboard failures

    NASA Astrophysics Data System (ADS)

    Kumar, Amit; Ram, Mangey

    2015-12-01

    Power generation is one of the most essential functions of any plant for continuous functioning without any interruption. A marine power plant (MPP) is in the same situation. In the present paper, the authors have tried to find the various reliability characteristics of a MPP. Using a marine power plant composed of two generators in which one of them is located at the stern and another at the bow, both associated to the main switch board (MSB). The distributive switch boards (DSB) receive power from the MSB through cables and their respective junctions. Given that arrangement, a working based transition state diagram has been generated. With the help of the Markov process, a number of intro-differential equations are formed and solved by Laplace transform. Various reliability characteristics are calculated and discussed with the help of graphs.

  12. SIZE DISTRIBUTION AND RATE OF PRODUCTION OF AIRBORNE PARTICULATE MATTER GENERATED DURING METAL CUTTING

    SciTech Connect

    M.A. Ebadian, Ph.D.; S.K. Dua, Ph.D., C.H.P.; Hillol Guha, Ph.D.

    2001-01-01

    During deactivation and decommissioning activities, thermal cutting tools, such as plasma torch, laser, and gasoline torch, are used to cut metals. These activities generate fumes, smoke and particulates. These airborne species of matter, called aerosols, may be inhaled if suitable respiratory protection is not used. Inhalation of the airborne metallic aerosols has been reported to cause ill health effects, such as acute respiratory syndrome and chromosome damage in lymphocytes. In the nuclear industry, metals may be contaminated with radioactive materials. Cutting these metals, as in size reduction of gloveboxes and tanks, produces high concentrations of airborne transuranic particles. Particles of the respirable size range (size < 10 {micro}m) deposit in various compartments of the respiratory tract, the fraction and the site in the respiratory tract depending on the size of the particles. The dose delivered to the respiratory tract depends on the size distribution of the airborne particulates (aerosols) and their concentration and radioactivity/toxicity. The concentration of airborne particulate matter in an environment is dependent upon the rate of their production and the ventilation rate. Thus, measuring aerosol size distribution and generation rate is important for (1) the assessment of inhalation exposures of workers, (2) the selection of respiratory protection equipment, and (3) the design of appropriate filtration systems. Size distribution of the aerosols generated during cutting of different metals by plasma torch was measured. Cutting rates of different metals, rate of generation of respirable mass, as well as the fraction of the released kerf that become respirable were determined. This report presents results of these studies. Measurements of the particles generated during cutting of metal plates with a plasma arc torch revealed the presence of particles with mass median aerodynamic diameters of particles close to 0.2 {micro}m, arising from

  13. Log-Cubic Method for Generation of Soil Particle Size Distribution Curve

    PubMed Central

    2013-01-01

    Particle size distribution (PSD) is a fundamental physical property of soils. Traditionally, the PSD curve was generated by hand from limited data of particle size analysis, which is subjective and may lead to significant uncertainty in the freehand PSD curve and graphically estimated cumulative particle percentages. To overcome these problems, a log-cubic method was proposed for the generation of PSD curve based on a monotone piecewise cubic interpolation method. The log-cubic method and commonly used log-linear and log-spline methods were evaluated by the leave-one-out cross-validation method for 394 soil samples extracted from UNSODA database. Mean error and root mean square error of the cross-validation show that the log-cubic method outperforms two other methods. What is more important, PSD curve generated by the log-cubic method meets essential requirements of a PSD curve, that is, passing through all measured data and being both smooth and monotone. The proposed log-cubic method provides an objective and reliable way to generate a PSD curve from limited soil particle analysis data. This method and the generated PSD curve can be used in the conversion of different soil texture schemes, assessment of grading pattern, and estimation of soil hydraulic parameters and erodibility factor. PMID:23766698

  14. Log-cubic method for generation of soil particle size distribution curve.

    PubMed

    Shang, Songhao

    2013-01-01

    Particle size distribution (PSD) is a fundamental physical property of soils. Traditionally, the PSD curve was generated by hand from limited data of particle size analysis, which is subjective and may lead to significant uncertainty in the freehand PSD curve and graphically estimated cumulative particle percentages. To overcome these problems, a log-cubic method was proposed for the generation of PSD curve based on a monotone piecewise cubic interpolation method. The log-cubic method and commonly used log-linear and log-spline methods were evaluated by the leave-one-out cross-validation method for 394 soil samples extracted from UNSODA database. Mean error and root mean square error of the cross-validation show that the log-cubic method outperforms two other methods. What is more important, PSD curve generated by the log-cubic method meets essential requirements of a PSD curve, that is, passing through all measured data and being both smooth and monotone. The proposed log-cubic method provides an objective and reliable way to generate a PSD curve from limited soil particle analysis data. This method and the generated PSD curve can be used in the conversion of different soil texture schemes, assessment of grading pattern, and estimation of soil hydraulic parameters and erodibility factor.

  15. A distributed big data storage and data mining framework for solar-generated electricity quantity forecasting

    NASA Astrophysics Data System (ADS)

    Wang, Jianzong; Chen, Yanjun; Hua, Rui; Wang, Peng; Fu, Jia

    2011-11-01

    Photovoltaic is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years. Solar photovoltaics are growing rapidly, albeit from a small base, to a total global capacity of 40,000 MW at the end of 2010. More than 100 countries use solar photovoltaics. Driven by advances in technology and increases in manufacturing scale and sophistication, the cost of photovoltaic has declined steadily since the first solar cells were manufactured. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity; have supported solar photovoltaics installations in many countries. However, the power that generated by solar photovoltaics is affected by the weather and other natural factors dramatically. To predict the photovoltaic energy accurately is of importance for the entire power intelligent dispatch in order to reduce the energy dissipation and maintain the security of power grid. In this paper, we have proposed a big data system--the Solar Photovoltaic Power Forecasting System, called SPPFS to calculate and predict the power according the real-time conditions. In this system, we utilized the distributed mixed database to speed up the rate of collecting, storing and analysis the meteorological data. In order to improve the accuracy of power prediction, the given neural network algorithm has been imported into SPPFS.By adopting abundant experiments, we shows that the framework can provide higher forecast accuracy-error rate less than 15% and obtain low latency of computing by deploying the mixed distributed database architecture for solar-generated electricity.

  16. A distributed big data storage and data mining framework for solar-generated electricity quantity forecasting

    NASA Astrophysics Data System (ADS)

    Wang, Jianzong; Chen, Yanjun; Hua, Rui; Wang, Peng; Fu, Jia

    2012-02-01

    Photovoltaic is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels composed of a number of solar cells containing a photovoltaic material. Due to the growing demand for renewable energy sources, the manufacturing of solar cells and photovoltaic arrays has advanced considerably in recent years. Solar photovoltaics are growing rapidly, albeit from a small base, to a total global capacity of 40,000 MW at the end of 2010. More than 100 countries use solar photovoltaics. Driven by advances in technology and increases in manufacturing scale and sophistication, the cost of photovoltaic has declined steadily since the first solar cells were manufactured. Net metering and financial incentives, such as preferential feed-in tariffs for solar-generated electricity; have supported solar photovoltaics installations in many countries. However, the power that generated by solar photovoltaics is affected by the weather and other natural factors dramatically. To predict the photovoltaic energy accurately is of importance for the entire power intelligent dispatch in order to reduce the energy dissipation and maintain the security of power grid. In this paper, we have proposed a big data system--the Solar Photovoltaic Power Forecasting System, called SPPFS to calculate and predict the power according the real-time conditions. In this system, we utilized the distributed mixed database to speed up the rate of collecting, storing and analysis the meteorological data. In order to improve the accuracy of power prediction, the given neural network algorithm has been imported into SPPFS.By adopting abundant experiments, we shows that the framework can provide higher forecast accuracy-error rate less than 15% and obtain low latency of computing by deploying the mixed distributed database architecture for solar-generated electricity.

  17. Semi-empirical model for the generation of dose distributions produced by a scanning electron beam

    SciTech Connect

    Nath, R.; Gignac, C.E.; Agostinelli, A.G.; Rothberg, S.; Schulz, R.J.

    1980-01-01

    There are linear accelerators (Sagittaire and Saturne accelerators produced by Compagnie Generale de Radiologie (CGR/MeV) Corporation) which produce broad, flat electron fields by magnetically scanning the relatively narrow electron beam as it emerges from the accelerator vacuum system. A semi-empirical model, which mimics the scanning action of this type of accelerator, was developed for the generation of dose distributions in homogeneous media. The model employs the dose distributions of the scanning electron beams. These were measured with photographic film in a polystyrene phantom by turning off the magnetic scanning system. The mean deviation calculated from measured dose distributions is about 0.2%; a few points have deviations as large as 2 to 4% inside of the 50% isodose curve, but less than 8% outside of the 50% isodose curve. The model has been used to generate the electron beam library required by a modified version of a commercially-available computerized treatment-planning system. (The RAD-8 treatment planning system was purchased from the Digital Equipment Corporation. It is currently available from Electronic Music Industries (EMI), Ltd.)

  18. Optimizing Geographic Allotment of Photovoltaic Capacity in a Distributed Generation Setting: Preprint

    SciTech Connect

    Urquhart, B.; Sengupta, M.; Keller, J.

    2012-09-01

    A multi-objective optimization was performed to allocate 2MW of PV among four candidate sites on the island of Lanai such that energy was maximized and variability in the form of ramp rates was minimized. This resulted in an optimal solution set which provides a range of geographic allotment alternatives for the fixed PV capacity. Within the optimal set, a tradeoff between energy produced and variability experienced was found, whereby a decrease in variability always necessitates a simultaneous decrease in energy. A design point within the optimal set was selected for study which decreased extreme ramp rates by over 50% while only decreasing annual energy generation by 3% over the maximum generation allocation. To quantify the allotment mix selected, a metric was developed, called the ramp ratio, which compares ramping magnitude when all capacity is allotted to a single location to the aggregate ramping magnitude in a distributed scenario. The ramp ratio quantifies simultaneously how much smoothing a distributed scenario would experience over single site allotment and how much a single site is being under-utilized for its ability to reduce aggregate variability. This paper creates a framework for use by cities and municipal utilities to reduce variability impacts while planning for high penetration of PV on the distribution grid.

  19. Artificial Bee Colony Algorithm for Transient Performance Augmentation of Grid Connected Distributed Generation

    NASA Astrophysics Data System (ADS)

    Chatterjee, A.; Ghoshal, S. P.; Mukherjee, V.

    In this paper, a conventional thermal power system equipped with automatic voltage regulator, IEEE type dual input power system stabilizer (PSS) PSS3B and integral controlled automatic generation control loop is considered. A distributed generation (DG) system consisting of aqua electrolyzer, photovoltaic cells, diesel engine generator, and some other energy storage devices like flywheel energy storage system and battery energy storage system is modeled. This hybrid distributed system is connected to the grid. While integrating this DG with the onventional thermal power system, improved transient performance is noticed. Further improvement in the transient performance of this grid connected DG is observed with the usage of superconducting magnetic energy storage device. The different tunable parameters of the proposed hybrid power system model are optimized by artificial bee colony (ABC) algorithm. The optimal solutions offered by the ABC algorithm are compared with those offered by genetic algorithm (GA). It is also revealed that the optimizing performance of the ABC is better than the GA for this specific application.

  20. Hardware random number generator base on monostable multivibrators dedicated for distributed measurement and control systems

    NASA Astrophysics Data System (ADS)

    Czernik, Pawel

    2013-10-01

    The hardware random number generator based on the 74121 monostable multivibrators for applications in cryptographically secure distributed measurement and control systems with asymmetric resources was presented. This device was implemented on the basis of the physical electronic vibration generator in which the circuit is composed of two "loop" 74121 monostable multivibrators, D flip-flop and external clock signal source. The clock signal, witch control D flip-flop was generated by a computer on one of the parallel port pins. There was presented programmed the author's acquisition process of random data from the measuring system to a computer. The presented system was designed, builded and thoroughly tested in the term of cryptographic security in our laboratory, what there is the most important part of this publication. Real cryptographic security was tested based on the author's software and the software environment called RDieHarder. The obtained results was here presented and analyzed in detail with particular reference to the specificity of distributed measurement and control systems with asymmetric resources.

  1. Parallel paving: An algorithm for generating distributed, adaptive, all-quadrilateral meshes on parallel computers

    SciTech Connect

    Lober, R.R.; Tautges, T.J.; Vaughan, C.T.

    1997-03-01

    Paving is an automated mesh generation algorithm which produces all-quadrilateral elements. It can additionally generate these elements in varying sizes such that the resulting mesh adapts to a function distribution, such as an error function. While powerful, conventional paving is a very serial algorithm in its operation. Parallel paving is the extension of serial paving into parallel environments to perform the same meshing functions as conventional paving only on distributed, discretized models. This extension allows large, adaptive, parallel finite element simulations to take advantage of paving`s meshing capabilities for h-remap remeshing. A significantly modified version of the CUBIT mesh generation code has been developed to host the parallel paving algorithm and demonstrate its capabilities on both two dimensional and three dimensional surface geometries and compare the resulting parallel produced meshes to conventionally paved meshes for mesh quality and algorithm performance. Sandia`s {open_quotes}tiling{close_quotes} dynamic load balancing code has also been extended to work with the paving algorithm to retain parallel efficiency as subdomains undergo iterative mesh refinement.

  2. Directions in US Air Force space power energy generation and distribution technology

    NASA Astrophysics Data System (ADS)

    Reinhardt, Kitt; Keener, Dave; Schuller, Mike

    1997-01-01

    Recent trends in the development of high efficiency, light-weight, reliable and cost-effective space power technologies needed to support the development of near-term, next-generation government and commercial satellites will be discussed. Significant advancements in light-weight and reduced volume electrical power system (EPS) components are required to enable the design of future smallsats with power requirements of less than 1000 W to monster-sats having projected power demands ranging from 10-50 kW for civilian and military communications and space based radar needs. For these missions increased emphasis is placed on reducing total satellite mass to enable use of smaller, less costly, and easier to deploy launch vehicles. In support of these requirements a complement of power generation, power management and distribution, and energy storage technologies are under development at the Air Force Phillips Laboratory Space and Missiles Technology Directorate. Specific technologies presented in this paper include high efficiency multijunction solar cells, low-cost thin-film solar cells, ultra light-weight flexible solar arrays, solar electric thermal converters, and high-voltage (70-130 V) and high-efficiency power management and distribution (PMAD) electronics. The projected impact of EPS subsystem performance on existing, near-term, and next-generation 10-50 kW military satellites will be discussed, along with technical issues and status of EPS component development.

  3. Unscheduled load flow effect due to large variation in the distributed generation in a subtransmission network

    NASA Astrophysics Data System (ADS)

    Islam, Mujahidul

    A sustainable energy delivery infrastructure implies the safe and reliable accommodation of large scale penetration of renewable sources in the power grid. In this dissertation it is assumed there will be no significant change in the power transmission and distribution structure currently in place; except in the operating strategy and regulatory policy. That is to say, with the same old structure, the path towards unveiling a high penetration of switching power converters in the power system will be challenging. Some of the dimensions of this challenge are power quality degradation, frequent false trips due to power system imbalance, and losses due to a large neutral current. The ultimate result is the reduced life of many power distribution components - transformers, switches and sophisticated loads. Numerous ancillary services are being developed and offered by the utility operators to mitigate these problems. These services will likely raise the system's operational cost, not only from the utility operators' end, but also reflected on the Independent System Operators and by the Regional Transmission Operators (RTO) due to an unforeseen backlash of frequent variation in the load-side generation or distributed generation. The North American transmission grid is an interconnected system similar to a large electrical circuit. This circuit was not planned but designed over 100 years. The natural laws of physics govern the power flow among loads and generators except where control mechanisms are installed. The control mechanism has not matured enough to withstand the high penetration of variable generators at uncontrolled distribution ends. Unlike a radial distribution system, mesh or loop networks can alleviate complex channels for real and reactive power flow. Significant variation in real power injection and absorption on the distribution side can emerge as a bias signal on the routing reactive power in some physical links or channels that are not distinguishable

  4. A Proton-Cyclotron Wave Storm Generated by Unstable Proton Distribution Functions in the Solar Wind

    NASA Technical Reports Server (NTRS)

    Wicks, R. T.; Alexander, R. L.; Stevens, M.; Wilson, L. B., III; Moya, P. S.; Vinas, A.; Jian, L. K.; Roberts, D. A.; O’Modhrain, S.; Gilbert, J. A.; Zurbuchen, T. H.

    2016-01-01

    We use audification of 0.092 seconds cadence magnetometer data from the Wind spacecraft to identify waves with amplitudes greater than 0.1 nanoteslas near the ion gyrofrequency (approximately 0.1 hertz) with duration longer than 1 hour during 2008. We present one of the most common types of event for a case study and find it to be a proton-cyclotron wave storm, coinciding with highly radial magnetic field and a suprathermal proton beam close in density to the core distribution itself. Using linear Vlasov analysis, we conclude that the long-duration, large-amplitude waves are generated by the instability of the proton distribution function. The origin of the beam is unknown, but the radial field period is found in the trailing edge of a fast solar wind stream and resembles other events thought to be caused by magnetic field footpoint motion or interchange reconnection between coronal holes and closed field lines in the corona.

  5. CDFTBL: A statistical program for generating cumulative distribution functions from data

    SciTech Connect

    Eslinger, P.W. )

    1991-06-01

    This document describes the theory underlying the CDFTBL code and gives details for using the code. The CDFTBL code provides an automated tool for generating a statistical cumulative distribution function that describes a set of field data. The cumulative distribution function is written in the form of a table of probabilities, which can be used in a Monte Carlo computer code. A a specific application, CDFTBL can be used to analyze field data collected for parameters required by the PORMC computer code. Section 2.0 discusses the mathematical basis of the code. Section 3.0 discusses the code structure. Section 4.0 describes the free-format input command language, while Section 5.0 describes in detail the commands to run the program. Section 6.0 provides example program runs, and Section 7.0 provides references. The Appendix provides a program source listing. 11 refs., 2 figs., 19 tabs.

  6. Mitigation of Power Quality Problems in Grid-Interactive Distributed Generation System

    NASA Astrophysics Data System (ADS)

    Bhende, C. N.; Kalam, A.; Malla, S. G.

    2016-04-01

    Having an inter-tie between low/medium voltage grid and distributed generation (DG), both exposes to power quality (PQ) problems created by each other. This paper addresses various PQ problems arise due to integration of DG with grid. The major PQ problems are due to unbalanced and non-linear load connected at DG, unbalanced voltage variations on transmission line and unbalanced grid voltages which severely affect the performance of the system. To mitigate the above mentioned PQ problems, a novel integrated control of distribution static shunt compensator (DSTATCOM) is presented in this paper. DSTATCOM control helps in reducing the unbalance factor of PCC voltage. It also eliminates harmonics from line currents and makes them balanced. Moreover, DSTATCOM supplies the reactive power required by the load locally and hence, grid need not to supply the reactive power. To show the efficacy of the proposed controller, several operating conditions are considered and verified through simulation using MATLAB/SIMULINK.

  7. Stationary distribution of self-organized states and biological information generation

    NASA Astrophysics Data System (ADS)

    Woo, Hyung Jun

    2013-11-01

    Self-organization, where spontaneous orderings occur under driven conditions, is one of the hallmarks of biological systems. We consider a statistical mechanical treatment of the biased distribution of such organized states, which become favored as a result of their catalytic activity under chemical driving forces. A generalization of the equilibrium canonical distribution describes the stationary state, which can be used to model shifts in conformational ensembles sampled by an enzyme in working conditions. The basic idea is applied to the process of biological information generation from random sequences of heteropolymers, where unfavorable Shannon entropy is overcome by the catalytic activities of selected genes. The ordering process is demonstrated with the genetic distance to a genotype with high catalytic activity as an order parameter. The resulting free energy can have multiple minima, corresponding to disordered and organized phases with first-order transitions between them.

  8. Layer 1 VPN services in distributed next-generation SONET/SDH networks with inverse multiplexing

    NASA Astrophysics Data System (ADS)

    Ghani, N.; Muthalaly, M. V.; Benhaddou, D.; Alanqar, W.

    2006-05-01

    Advances in next-generation SONET/SDH along with GMPLS control architectures have enabled many new service provisioning capabilities. In particular, a key services paradigm is the emergent Layer 1 virtual private network (L1 VPN) framework, which allows multiple clients to utilize a common physical infrastructure and provision their own 'virtualized' circuit-switched networks. This precludes expensive infrastructure builds and increases resource utilization for carriers. Along these lines, a novel L1 VPN services resource management scheme for next-generation SONET/SDH networks is proposed that fully leverages advanced virtual concatenation and inverse multiplexing features. Additionally, both centralized and distributed GMPLS-based implementations are also tabled to support the proposed L1 VPN services model. Detailed performance analysis results are presented along with avenues for future research.

  9. Heterogeneously integrated III-V/silicon dual-mode distributed feedback laser array for terahertz generation.

    PubMed

    Shao, Haifeng; Keyvaninia, Shahram; Vanwolleghem, Mathias; Ducournau, Guillaume; Jiang, Xiaoqing; Morthier, Geert; Lampin, Jean-Francois; Roelkens, Gunther

    2014-11-15

    We demonstrate an integrated distributed feedback (DFB) laser array as a dual-wavelength source for narrowband terahertz (THz) generation. The laser array is composed of four heterogeneously integrated III-V-on-silicon DFB lasers with different lengths enabling dual-mode lasing tolerant to process variations, bias fluctuations, and ambient temperature variations. By optical heterodyning the two modes emitted by the dual-wavelength DFB laser in the laser array using a THz photomixer composed of an uni-traveling carrier photodiode (UTC-PD), a narrow and stable carrier signal with a frequency of 0.357 THz is generated. The central operating frequency and the emitted terahertz wave linewidth are analyzed, along with their dependency on the bias current applied to the laser diode and ambient temperature.

  10. Tunable microwave generation of a monolithic dual-wavelength distributed feedback laser.

    PubMed

    Lo, Yen-Hua; Wu, Yu-Chang; Hsu, Shun-Chieh; Hwang, Yi-Chia; Chen, Bai-Ci; Lin, Chien-Chung

    2014-06-02

    The dynamic behavior of a monolithic dual-wavelength distributed feedback laser was fully investigated and mapped. The combination of different driving currents for master and slave lasers can generate a wide range of different operational modes, from single mode, period 1 to chaos. Both the optical and microwave spectrum were recorded and analyzed. The detected single mode signal can continuously cover from 15GHz to 50GHz, limited by photodetector bandwidth. The measured optical four-wave-mixing pattern indicates that a 70GHz signal can be generated by this device. By applying rate equation analysis, the important laser parameters can be extracted from the spectrum. The extracted relaxation resonant frequency is found to be 8.96GHz. With the full operational map at hand, the suitable current combination can be applied to the device for proper applications.

  11. Aerosol generation and distribution system for the Third International Cloud Condensation Nuclei Workshop

    NASA Technical Reports Server (NTRS)

    Katz, U.; Dea, J. Y.

    1981-01-01

    In order to obtain identical samples participating CCN instruments and aerosol characterizing equipment were located along and connected to a 8.2 cm diameter aluminum tube through which the test aerosols were pumped directly from the source at very slight overpressure. Of the total of 29 experiments, 18 were carried out with artificial NaCl or (NH4)2SO4 aerosols. These were generated from salt solutions by pneumatic atomizers of special design to ensure high constancy of the aerosol output concentration. In three experiments with insoluble CCN (AgI, paraffin wax) the aerosols were generated thermally. In some of the tests, an electrostatic classifier was used for narrowing the particle size distributions.

  12. Three dimensional potential and current distributions in a Hall generator with assumed velocity profiles

    NASA Technical Reports Server (NTRS)

    Stankiewicz, N.; Palmer, R. W.

    1972-01-01

    Three-dimensional potential and current distributions in a Faraday segmented MHD generator operating in the Hall mode are computed. Constant conductivity and a Hall parameter of 1.0 is assumed. The electric fields and currents are assumed to be coperiodic with the electrode structure. The flow is assumed to be fully developed and a family of power-law velocity profiles, ranging from parabolic to turbulent, is used to show the effect of the fullness of the velocity profile. Calculation of the square of the current density shows that nonequilibrium heating is not likely to occur along the boundaries. This seems to discount the idea that the generator insulating walls are regions of high conductivity and are therefore responsible for boundary-layer shorting, unless the shorting is a surface phenomenon on the insulating material.

  13. Understanding Coronal Heating with Emission Measure Distributions

    NASA Technical Reports Server (NTRS)

    Klimchik, James A.; Tripathi, Durgesh; Bradshaw, Stephen J.; Mason, Helen E.

    2011-01-01

    It is widely believed that the cross-field spatial scale of coronal heating is small, so that the fundamental plasma structures (loop strands) are spatially unresolved. We therefore must appeal to diagnostic techniques that are not strongly affected by spatial averaging. One valuable observable is the emission measure distribution, EM(T), which indicates how much material is present at each temperature. Using data from the Extreme-ultraviolet Imaging Spectrograph on the Hinode mission, we have determined emission measure distributions in the cores of two active regions. The distributions have power law slopes of approximately 2.4 coolward of the peak. We compare these slopes, as well as the amount of emission measure at very high temperature, with the predictions of a series of models. The models assume impulsive heating (nanoflares) in unresolved strands and take full account of non equilibrium ionization. A variety of nanoflare properties and initial conditions are considered. We also comment on the selection of spectral lines for upcoming missions like Solar Orbiter.

  14. An Estimation Method for Distribution System Load with Photovoltaic Power Generation based on ICA

    NASA Astrophysics Data System (ADS)

    Yamada, Takayoshi; Ishigame, Atsushi; Genji, Takamu

    A large number of Dispersed Generations (DGs) are expected to be installed in distribution systems. Therefore the state estimation is important problem for stable and reliable system operation. However, it is difficult to estimate the total power of DGs connected to a load-side system from a metering spot on the distribution line because at the metering spot only a sum of the active-power from various loads and DGs can be measured. In this paper, we propose an estimation method for unknown DG-outputs connected to a distribution system. This method enables to estimate DG-outputs by analyzing a power flow data measured at one spot using independent component analysis (ICA). The estimation by ICA needs the same number of observations as estimations. However the observation spot is extremely limited in existing distribution system. So we propose an estimation method which enables to estimate DG-outputs and load-changes from only an observation by using known information of load power and a priori knowledge of insolation.

  15. A distributed system for fast alignment of next-generation sequencing data.

    PubMed

    Srimani, Jaydeep K; Wu, Po-Yen; Phan, John H; Wang, May D

    2010-12-01

    We developed a scalable distributed computing system using the Berkeley Open Interface for Network Computing (BOINC) to align next-generation sequencing (NGS) data quickly and accurately. NGS technology is emerging as a promising platform for gene expression analysis due to its high sensitivity compared to traditional genomic microarray technology. However, despite the benefits, NGS datasets can be prohibitively large, requiring significant computing resources to obtain sequence alignment results. Moreover, as the data and alignment algorithms become more prevalent, it will become necessary to examine the effect of the multitude of alignment parameters on various NGS systems. We validate the distributed software system by (1) computing simple timing results to show the speed-up gained by using multiple computers, (2) optimizing alignment parameters using simulated NGS data, and (3) computing NGS expression levels for a single biological sample using optimal parameters and comparing these expression levels to that of a microarray sample. Results indicate that the distributed alignment system achieves approximately a linear speed-up and correctly distributes sequence data to and gathers alignment results from multiple compute clients.

  16. Graphene Distributed Amplifiers: Generating Desirable Gain for Graphene Field-Effect Transistors

    PubMed Central

    Lyu, Hongming; Lu, Qi; Huang, Yilin; Ma, Teng; Zhang, Jinyu; Wu, Xiaoming; Yu, Zhiping; Ren, Wencai; Cheng, Hui-Ming; Wu, Huaqiang; Qian, He

    2015-01-01

    Ever since its discovery, graphene bears great expectations in high frequency electronics due to its irreplaceably high carrier mobility. However, it has long been blamed for the weakness in generating gains, which seriously limits its pace of development. Distributed amplification, on the other hand, has successfully been used in conventional semiconductors to increase the amplifiers’ gain-bandwidth product. In this paper, distributed amplification is first applied to graphene. Transmission lines phase-synchronize paralleled graphene field-effect transistors (GFETs), combining the gain of each stage in an additive manner. Simulations were based on fabricated GFETs whose fT ranged from 8.5 GHz to 10.5 GHz and fmax from 12 GHz to 14 GHz. A simulated four-stage graphene distributed amplifier achieved up to 4 dB gain and 3.5 GHz bandwidth, which could be realized with future IC processes. A PCB level graphene distributed amplifier was fabricated as a proof of circuit concept. PMID:26634442

  17. Internal stress distribution for generating closure domains in laser-irradiated Fe–3%Si(110) steels

    SciTech Connect

    Iwata, Keiji; Imafuku, Muneyuki; Orihara, Hideto; Sakai, Yusuke; Ohya, Shin-Ichi; Suzuki, Tamaki; Shobu, Takahisa; Akita, Koichi; Ishiyama, Kazushi

    2015-05-07

    Internal stress distribution for generating closure domains occurring in laser-irradiated Fe–3%Si(110) steels was investigated using high-energy X-ray analysis and domain theory based on the variational principle. The measured triaxial stresses inside the specimen were compressive and the stress in the rolling direction became more dominant than stresses in the other directions. The calculations based on the variational principle of magnetic energy for closure domains showed that the measured triaxial stresses made the closure domains more stable than the basic domain without closure domains. The experimental and calculation results reveal that the laser-introduced internal stresses result in the occurrence of the closure domains.

  18. Transform-limited pulses generated by an actively Q-switched distributed fiber laser.

    PubMed

    Cuadrado-Laborde, C; Pérez-Millán, P; Andrés, M V; Díez, A; Cruz, J L; Barmenkov, Yu O

    2008-11-15

    A single-mode, transform-limited, actively Q-switched distributed-feedback fiber laser is presented, based on a new in-line acoustic pulse generator. Our technique permits a continuous adjustment of the repetition rate that modulates the Q factor of the cavity. Optical pulses of 800 mW peak power, 32 ns temporal width, and up to 20 kHz repetition rates were obtained. The measured linewidth demonstrates that these pulses are transform limited: 6 MHz for a train of pulses of 10 kHz repetition rate, 80 ns temporal width, and 60 mW peak power. Efficient excitation of spontaneous Brillouin scattering is demonstrated.

  19. Giant enhancement of second harmonic generation in nonlinear photonic crystals with distributed Bragg reflector mirrors.

    PubMed

    Ren, Ming-Liang; Li, Zhi-Yuan

    2009-08-17

    We theoretically investigate second harmonic generation (SHG) in one-dimensional multilayer nonlinear photonic crystal (NPC) structures with distributed Bragg reflector (DBR) as mirrors. The NPC structures have periodic modulation on both the linear and second-order susceptibility. Three major physical mechanisms, quasi-phase matching (QPM) effect, slow light effect at photonic band gap edges, and cavity effect induced by DBR mirrors can be harnessed to enhance SHG. Selection of appropriate structural parameters can facilitate coexistence of these mechanisms to act collectively and constructively to create very high SHG conversion efficiency with an enhancement by up to seven orders of magnitude compared with the ordinary NPC where only QPM works.

  20. A Cost to Benefit Analysis of a Next Generation Electric Power Distribution System

    NASA Astrophysics Data System (ADS)

    Raman, Apurva

    This thesis provides a cost to benefit analysis of the proposed next generation of distribution systems- the Future Renewable Electric Energy Distribution Management (FREEDM) system. With the increasing penetration of renewable energy sources onto the grid, it becomes necessary to have an infrastructure that allows for easy integration of these resources coupled with features like enhanced reliability of the system and fast protection from faults. The Solid State Transformer (SST) and the Fault Isolation Device (FID) make for the core of the FREEDM system and have huge investment costs. Some key features of the FREEDM system include improved power flow control, compact design and unity power factor operation. Customers may observe a reduction in the electricity bill by a certain fraction for using renewable sources of generation. There is also a possibility of huge subsidies given to encourage use of renewable energy. This thesis is an attempt to quantify the benefits offered by the FREEDM system in monetary terms and to calculate the time in years required to gain a return on investments made. The elevated cost of FIDs needs to be justified by the advantages they offer. The result of different rates of interest and how they influence the payback period is also studied. The payback periods calculated are observed for viability. A comparison is made between the active power losses on a certain distribution feeder that makes use of distribution level magnetic transformers versus one that makes use of SSTs. The reduction in the annual active power losses in the case of the feeder using SSTs is translated onto annual savings in terms of cost when compared to the conventional case with magnetic transformers. Since the FREEDM system encourages operation at unity power factor, the need for installing capacitor banks for improving the power factor is eliminated and this reflects in savings in terms of cost. The FREEDM system offers enhanced reliability when compared to a

  1. Subsurface Droplet Size Distribution generated as breaking waves entrain an oil slick

    NASA Astrophysics Data System (ADS)

    Li, Cheng; Miller, Jesse; Katz, Joseph

    2016-11-01

    Breaking waves are a primary mechanism for entraining and dispersing oil spills. Knowledge of the resulting droplet size distribution is crucial for predicting the transport and fate of this oil. In this on-going experimental study, a controlled oil slick of varying viscosity (μd) , density (ρd), interfacial tension (σ) , and thickness δ = 0.5mm are entrained by waves of varying energy (Ew) . The changes to droplet size over time, from seconds to hours, are measured at several locations using multi-resolution holography, which covers sizes ranging from μm to mm. Using dispersants to reduce σ, the Webber number, We =Ew δ / σ , and Ohnesorge number, Oh =μd /(ρd δσ) 0 . 5 , are varied from 6 to 813 and from 0.09 to 0.95, respectively. Droplets smaller than the turbulence scale (2-30 μm - diameter), are generated by "micro-threading". Their size distribution becomes steeper and their total number increase substantially with decreasing interfacial tension. For slopes smaller than -3, measured for σ around 10-1 mN/m, the volumetric size distribution decreases with diameter, i.e. most of the oil breaks into micron-scale droplets. For high interfacial tension oil, the concentration of small droplets increases with wave energy, but this effect diminishes as σ decreases. Droplets larger than 100 μm are generated by turbulent shear. Hence, their number is impacted by μd and Ew. Increasing We from 6 to 15 (Oh from 0.09 to 2.95) increases the initial number of droplets by up to 5 times, but the distribution slopes remain largely similar. Supported by Gulf of Mexico Research Initiative (GoMRI).

  2. Onsite Distributed Generation Systems For Laboratories, Laboratories for the 21st Century: Best Practices (Brochure)

    SciTech Connect

    Not Available

    2011-09-01

    This guide provides general information on implementing onsite distributed generation systems in laboratory environments. Specific technology applications, general performance information, and cost data are provided to educate and encourage laboratory energy managers to consider onsite power generation or combined heat and power (CHP) systems for their facilities. After conducting an initial screening, energy managers are encouraged to conduct a detailed feasibility study with actual cost and performance data for technologies that look promising. Onsite distributed generation systems are small, modular, decentralized, grid-connected, or off-grid energy systems. These systems are located at or near the place where the energy is used. These systems are also known as distributed energy or distributed power systems. DG technologies are generally considered those that produce less than 20 megawatts (MW) of power. A number of technologies can be applied as effective onsite DG systems, including: (1) Diesel, natural gas, and dual-fuel reciprocating engines; (2) Combustion turbines and steam turbines; (3) Fuel cells; (4) Biomass heating; (5) Biomass combined heat and power; (6) Photovoltaics; and (7) Wind turbines. These systems can provide a number of potential benefits to an individual laboratory facility or campus, including: (1) High-quality, reliable, and potentially dispatchable power; (2) Low-cost energy and long-term utility cost assurance, especially where electricity and/or fuel costs are high; (3) Significantly reduced greenhouse gas (GHG) emissions. Typical CHP plants reduce onsite GHG by 40 to 60 percent; (4) Peak demand shaving where demand costs are high; (5) CHP where thermal energy can be used in addition to electricity; (6) The ability to meet standby power needs, especially where utility-supplied power is interrupted frequently or for long periods and where standby power is required for safety or emergencies; and (7) Use for standalone or off

  3. Size distribution of chromate paint aerosol generated in a bench-scale spray booth.

    PubMed

    Sabty-Daily, Rania A; Hinds, William C; Froines, John R

    2005-01-01

    Spray painters are potentially exposed to aerosols containing hexavalent chromium [Cr(VI)] via inhalation of chromate-based paint sprays. Evaluating the particle size distribution of a paint spray aerosol, and the variables that may affect this distribution, is necessary to determine the site and degree of respiratory deposition and the damage that may result from inhaled Cr(VI)-containing paint particles. This study examined the effect of spray gun atomization pressure, aerosol generation source and aerosol aging on the size distribution of chromate-based paint overspray aerosols generated in a bench-scale paint spray booth. The study also determined the effect of particle bounce inside a Marple personal cascade impactor on measured size distributions of paint spray aerosols. Marple personal cascade impactors with a modified inlet were used for sample collection. The data indicated that paint particle bounce did not occur inside the cascade impactors sufficiently to affect size distribution when using uncoated stainless steel or PVC substrate sampling media. A decrease in paint aerosol mass median aerodynamic diameter (MMAD) from 8.2 to 7.0 mum was observed as gun atomization pressure increased from 6 to 10 psi. Overspray aerosols were sampled at two locations in the spray booth. A downstream sampling position simulated the exposure of a worker standing between the painted surface and exhaust, a situation encountered in booths with multiple workers. The measured mean MMAD was 7.2 mum. The distance between the painted surface and sampler was varied to sample oversprays of varying ages between 2.8 and 7.7 s. Age was not a significant factor for determining MMAD. Overspray was sampled at a 90 degrees position to simulate a worker standing in front of the surface being painted with air flowing to the worker's side, a common situation in field applications. The resulting overspray MMAD averaged 5.9 mum. Direct-spray aerosols were sampled at ages from 5.3 to 11.7 s

  4. An Efficacious Multi-Objective Fuzzy Linear Programming Approach for Optimal Power Flow Considering Distributed Generation

    PubMed Central

    Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri

    2016-01-01

    This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality. PMID:26954783

  5. An Efficacious Multi-Objective Fuzzy Linear Programming Approach for Optimal Power Flow Considering Distributed Generation.

    PubMed

    Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri

    2016-01-01

    This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality.

  6. ZTEK`s ultra-high efficiency fuel cell/gas turbine system for distributed generation

    SciTech Connect

    Hsu, M.; Nathanson, D.; Bradshaw, D.T.

    1996-12-31

    Ztek`s Planar Solid Oxide Fuel Cell (SOFC) system has exceptional potential for utility electric power generation because of: simplicity of components construction, capability for low cost manufacturing, efficient recovery of very high quality by-product heat (up to 1000{degrees}C), and system integration simplicity. Utility applications of the Solid Oxide Fuel Cell are varied and include distributed generation units (sub-MW to 30MW capacity), repowering existing power plants (i.e. 30MW to 100MW), and multi-megawatt central power plants. A TVA/EPRI collaboration program involved functional testing of the advanced solid oxide fuel cell stacks and design scale-up for distributed power generation applications. The emphasis is on the engineering design of the utility modules which will be the building blocks for up to megawatt scale power plants. The program has two distinctive subprograms: Verification test on a 1 kW stack and 25kW module for utility demonstration. A 1 kW Planar SOFC stack was successfully operated for 15,000 hours as of December, 1995. Ztek began work on a 25kW SOFC Power System for TVA, which plans to install the 25kW SOFC at a host site for demonstration in 1997. The 25kW module is Ztek`s intended building block for the commercial use of the Planar SOFC. Systems of up to megawatt capacity can be obtained by packaging the modules in 2-dimensional or 3-dimensional arrays.

  7. Nonlinear probability distributions of waves in bimodal following and crossing seas generated in laboratory experiments

    NASA Astrophysics Data System (ADS)

    Petrova, P. G.; Guedes Soares, C.

    2013-10-01

    This paper presents an analysis of the nonlinear distributions of crests, troughs and heights of deep water waves from mixed following sea states generated mechanically in an offshore basin and compares with previous results for mixed crossing seas from the same experiment. The random signals at the wavemaker in both types of mixed seas are characterized by bimodal spectra following the model of Guedes Soares (1984). In agreement with the Benjamin-Feir mechanism, the high-frequency spectrum shows decrease of the peak magnitude and downshift of the peak with the distance, as well as reduction of the tail. The observed statistics and probabilistic distributions exhibit, in general, increasing effects of third-order nonlinearity with the distance from the wavemaker. However, this effect is less pronounced in the wave systems with two following wave trains than in the crossing seas with identical initial spectral characteristics. The relevance of third-order effects due to free modes only is demonstrated and assessed by excluding the vertically asymmetric distortions induced by bound-wave effects of second and third order. The fact that for records characterized by relatively large coefficient of kurtosis, the empirical distributions for the non-skewed profiles continue deviating from the linear predictions, corroborate the relevance of free-wave interactions and thus the need of using higher-order models for the description of wave data.

  8. Distributions of nonlinear wave amplitudes and heights from laboratory generated following and crossing bimodal seas

    NASA Astrophysics Data System (ADS)

    Petrova, P. G.; Guedes Soares, C.

    2014-05-01

    This paper presents an analysis of the distributions of nonlinear crests, troughs and heights of deep water waves from mixed following sea states generated mechanically in an offshore basin and compares with previous results for mixed crossing seas from the same experiment. The random signals at the wavemaker in both types of mixed seas are characterized by bimodal spectra following the model of Guedes Soares (1984). In agreement with the Benjamin-Feir mechanism, the high-frequency spectrum shows a decrease in the peak magnitude and downshift of the peak with the distance, as well as reduction of the tail. The observed statistics and probabilistic distributions exhibit, in general, increasing effects of third-order nonlinearity with the distance from the wavemaker. However, this effect is less pronounced in the wave systems with two following wave trains than in the crossing seas, given that they have identical initial characteristics of the bimodal spectra. The relevance of third-order effects due to free modes only is demonstrated and assessed by excluding the vertically asymmetric distortions induced by bound wave effects of second and third order. The fact that for records characterized by relatively large coefficient of kurtosis, the empirical distributions for the non-skewed profiles continue deviating from the linear predictions, corroborate the relevance of free wave interactions and thus the need of using higher-order models for the description of wave data.

  9. Viability of Small Wind Distributed Generation for Farmers Who Irrigate (Poster)

    SciTech Connect

    Meadows, B.; Forsyth, T.; Johnson, S.; Healow, D.

    2010-05-01

    About 14% of U.S. farms are irrigated, representing 55 million acres of irrigated land. Irrigation on these farms is a major energy user in the United States, accounting for one-third of water withdrawals and 137 billion gallons per day. More than half of the Irrigation systems use electric energy. Wind energy can be a good choice for meeting irrigation energy needs. Nine of the top 10 irrigation states (California, Texas, Idaho, Arkansas, Colorado, Nebraska, Arizona, Kansas, Washington, and Oregon) have good to excellent wind resources. Many rural areas have sufficient wind speeds to make wind an attractive alternative, and farms and ranches can often install a wind energy system without impacting their ability to plant crops and graze livestock. Additionally, the rising and uncertain future costs of diesel, natural gas, and even electricity increase the potential effectiveness for wind energy and its predictable and competitive cost. In general, wind-powered electric generation systems generate more energy in the winter months than in the summer months when most crops need the water. Therefore, those states that have a supportive net metering policy can dramatically impact the viability of an onsite wind turbine. This poster presentation highlights case studies that show favorable and unfavorable policies that impact the growth of small wind in this important sector and demonstrate how net metering policies affect the viability of distributed wind generation for farmers who irrigate.

  10. Creating markets for combined heat and power and clean distributed generation in New York State.

    PubMed

    Bourgeois, Thomas G; Hedman, Bruce; Zalcman, Fred

    2003-01-01

    Combined heat and power (CHP) is the simultaneous production of electrical or mechanical power and thermal energy from in a single process. Because thermal output from the generation of electricity is captured and utilized onsite, CHP systems can achieve efficiencies from 60% to as high as 90%. In contrast generation of electric power at sites remote from the loads served often results in efficiencies of 33% or less due to losses in generation and transmission and distribution of the power to ultimate end users. A well designed CHP system is the essence of energy efficiency. It may also provide significant environmental benefits. However, the full promise of CHP for improving the efficiency and productivity of businesses and the quality of the environment is unlikely to be realized given the current market structure and regulatory environment in which CHP projects are forced to compete. This paper examines the market structure and regulatory obstacles that hinder the development of more robust markets for CHP in New York State.

  11. Capital accumulation, income distribution and endogenous fertility in an overlapping generations general equilibrium model.

    PubMed

    Raut, L K

    1991-01-01

    A study is conducted in attempts to increase the understanding of the links between macroeconomic effects and causes of population growth in formulating policy. An overlapping generations general equilibrium model is employed aggregating household decisions about fertility, savings, and investment in the human capital of children with the objective of studying intertemporal relationships among population growth, income distribution, inter-generation social mobility, skill composition of the labor force, and household income. As a result of endogenous fertility, the equilibrium path attains steady state from the second generation. Income tax transfer, child taxation, and social security taxation policies are also examined in the paper. A structural explanation is given for the inverse household income-child quantity and negative child quality-quantity relationships seen in developing countries. In a Cobb-Douglas economy, these relationships hold in the short-run, potentially working over the long-run in other economies. Overall, the model shows that group interests may hinder emergence of perfect capital markets with private initiatives. Where developing countries are concerned, these results have strong implications for population policy. A policy mix of building good quality schools, or subsidizing rural education, introducing a formal social security program, and providing high-yield, risk-free investments, banking, and insurance services to the poor is recommended.

  12. Study of the longitudinal distribution of power generated in a random distributed feedback Raman fibre laser with unidirectional pumping

    SciTech Connect

    Churkin, D V; El-Taher, A E; Vatnik, I D; Babin, Sergei A

    2012-09-30

    The longitudinal distribution of the Stokes-component power in a Raman fibre laser with a random distributed feedback and unidirectional pumping is measured. The fibre parameters (linear loss and Rayleigh backscattering coefficient) are calculated based on the distributions obtained. A numerical model is developed to describe the lasing power distribution. The simulation results are in good agreement with the experimental data. (optical fibres, lasers and amplifiers. properties and applications)

  13. Reliable, Low-Cost Distributed Generator/Utility System Interconnect: Final Subcontract Report, November 2001-March 2004

    SciTech Connect

    Ye, Z.; Walling, R.; Miller, N.; Du, P.; Nelson, K.; Li, L.; Zhou, R.; Garces, L.; Dame, M.

    2006-03-01

    This report summarizes the detailed study and development of new GE anti-islanding controls for two classes of distributed generation. One is inverter-interfaced, while the other is synchronous machine interfaced.

  14. The impact of distributed generation on the Thailand's electric power system

    NASA Astrophysics Data System (ADS)

    Fuangfoo, Pradit

    Typically, subtransmission and distribution systems are a radial configuration and have only one source from a main grid. The subtransmission and distribution systems are usually not designed to operate with the Distributed Generation (DG) connecting to the systems. In recent years, the installation capacity of DG has increased significantly in the Electrical Power System (EPS), particularly in the subtransmission and distribution systems due to the economical and technical benefits associated with DG such as higher efficiencies, reduced system losses, and enhanced system reliability. If the penetration level of DG continues to increase while the EPS remain unchanged, technical conflicts may develop in the future. In this dissertation, the impact study focuses on the Thailand's EPS. The research performs systematic approach to evaluate the impact of DG on the whole Thailand's ESP and on the local system (subtransmission and distribution systems). This dissertation investigates the effect of DG on both steady-stead and dynamic performance of the whole system. The influence of penetration level together with types and operation modes of DGs are also included. The steady-state study analyzes the effect of DG on voltage profile, system losses, and transmission line usages during normal and abnormal condition, whereas the dynamic impact concentrates on the effect of DG on dynamic stability and small signal stability. The investigated results can be drawn into the policy to determine the maximum penetration level of DG spread out the whole system to avoid the adverse effect from DG. Similarly, the impact study of DG on local system (subtransmission and distribution system) also includes the influence of DG on steady-state and dynamic performance of the system. The steady-state impact of DG on local system focuses on voltage profile, system losses, protection coordination, harmonics, and system reliability. For dynamic impact of DG on local system, the main concern is

  15. Monolithic dual-mode distributed feedback semiconductor laser for tunable continuous-wave terahertz generation.

    PubMed

    Kim, Namje; Shin, Jaeheon; Sim, Eundeok; Lee, Chul Wook; Yee, Dae-Su; Jeon, Min Yong; Jang, Yudong; Park, Kyung Hyun

    2009-08-03

    We report on a monolithic dual-mode semiconductor laser operating in the 1550-nm range as a compact optical beat source for tunable continuous-wave (CW) terahertz (THz) generation. It consists of two distributed feedback (DFB) laser sections and one phase section between them. Each wavelength of the two modes can be independently tuned by adjusting currents in micro-heaters which are fabricated on the top of the each DFB section. The continuous tuning of the CW THz emission from Fe(+)-implanted InGaAs photomixers is successfully demonstrated using our dual-mode laser as the excitation source. The CW THz frequency is continuously tuned from 0.17 to 0.49 THz.

  16. Velocity and temperature distributions of coal-slag layers on magnetohydrodynamic generators walls

    NASA Technical Reports Server (NTRS)

    Pian, C. C. P.; Smith, J. M.

    1977-01-01

    Approximate analytical expressions are derived for the velocity and temperature distributions in steady state coal slag deposits flowing over MHD generator walls. Effects of slag condensation and Joule heating are included in the analysis. The transport conditions and the slag temperature at the slag-gas interface are taken to be known parameters in the formulation. They are assumed to have been predetermined either experimentally or from the slag properties and the gas dynamic calculations of the free stream flow. The analysis assumes a power law velocity profile for the slag and accounts for the coupling between the energy and momentum conservation equations. Comparisons are made with the more exact numerical solutions to verify the accuracy of the results.

  17. A modified ziggurat algorithm for generating exponentially- and normally-distributed pseudorandom numbers

    PubMed Central

    McFarland, Christopher D

    2015-01-01

    The Ziggurat Algorithm is a very fast rejection sampling method for generating PseudoRandom Numbers (PRNs) from statistical distributions. In the algorithm, rectangular sampling domains are layered on top of each other (resembling a ziggurat) to encapsulate the desired probability density function. Random values within these layers are sampled and then returned if they lie beneath the graph of the probability density function. Here, we present an implementation where ziggurat layers reside completely beneath the probability density function, thereby eliminating the need for any rejection test within the ziggurat layers. In the new algorithm, small overhanging segments of probability density remain to the right of each ziggurat layer, which can be efficiently sampled with triangularly-shaped sampling domains. Median runtimes of the new algorithm for exponential and normal variates is reduced to 58% and 53% respectively (collective range: 41–93%). An accessible C library, along with extensions into Python and MATLAB/Octave are provided. PMID:27041780

  18. Spectroscopic measurement of ion temperature and ion velocity distributions in the flux-coil generated FRC.

    PubMed

    Gupta, D; Bolte, N; Gota, H; Hayashi, R; Kiyashko, V; Marsili, P; Morehouse, M; Primavera, S; Roche, T; Wessel, F

    2010-10-01

    One aim of the flux-coil generated field reversed configuration at Tri Alpha Energy (TAE) is to establish the plasma where the ion rotational energy is greater than the ion thermal energy. To verify this, an optical diagnostic was developed to simultaneously measure the Doppler velocity-shift and line-broadening using a 0.75 m, 1800 groves/mm, spectrometer. The output spectrum is magnified and imaged onto a 16-channel photomultiplier tube (PMT) array. The individual PMT outputs are coupled to high-gain, high-frequency, transimpedance amplifiers, providing fast-time response. The Doppler spectroscopy measurements, along with a survey spectrometer and photodiode-light detector, form a suite of diagnostics that provide insights into the time evolution of the plasma-ion distribution and current when accelerated by an azimuthal-electric field.

  19. Spectroscopic measurement of ion temperature and ion velocity distributions in the flux-coil generated FRC

    SciTech Connect

    Gupta, D.; Gota, H.; Hayashi, R.; Kiyashko, V.; Morehouse, M.; Primavera, S.; Bolte, N.; Marsili, P.; Roche, T.; Wessel, F.

    2010-10-15

    One aim of the flux-coil generated field reversed configuration at Tri Alpha Energy (TAE) is to establish the plasma where the ion rotational energy is greater than the ion thermal energy. To verify this, an optical diagnostic was developed to simultaneously measure the Doppler velocity-shift and line-broadening using a 0.75 m, 1800 groves/mm, spectrometer. The output spectrum is magnified and imaged onto a 16-channel photomultiplier tube (PMT) array. The individual PMT outputs are coupled to high-gain, high-frequency, transimpedance amplifiers, providing fast-time response. The Doppler spectroscopy measurements, along with a survey spectrometer and photodiode-light detector, form a suite of diagnostics that provide insights into the time evolution of the plasma-ion distribution and current when accelerated by an azimuthal-electric field.

  20. Analysis of spatial lamellar distribution from adaptive-optics second harmonic generation corneal images.

    PubMed

    Bueno, Juan M; Palacios, Raquel; Chessey, Mary K; Ginis, Harilaos

    2013-07-01

    The spatial organization of stromal collagen of ex-vivo corneas has been quantified in adaptive-optics second harmonic generation (SHG) images by means of an optimized Fourier transform (FT) based analysis. At a particular depth location, adjacent lamellae often present similar orientations and run parallel to the corneal surface. However this pattern might be combined with interweaved collagen bundles leading to crosshatched structures with different orientations. The procedure here reported provides us with both principal and crosshatched angles. This is also able to automatically distinguish a random distribution from a cross-shaped one, since it uses the ratio of the axes lengths of the best-fitted ellipse of the FT data as an auxiliary parameter. The technique has successfully been applied to SHG images of healthy corneas (both stroma and Bowman's layer) of different species and to corneas undergoing cross-linking treatment.

  1. Research and development on a distributed type solar thermal power generation plant

    NASA Astrophysics Data System (ADS)

    Sumida, I.; Tsukamoto, M.; Sakamoto, T.; Taki, T.; Sato, S.

    1983-12-01

    The R&D on a solar thermal power generation system of the plane parabolic type within the framework of the Japanese Sunshine Project is described. This system realizes high concentration of solar energy with a special concentrator module which combines 100 flat plate mirror heliostats of the central tower system with 5 parabolic troughs of the distributed system. A molten salt (KCl-LiCl) type thermal storage unit is used to superheat saturated steam supplied by accumulators to 300-350 C for 90 minutes after 5 hours of heat storage. Specifications and hydrodynamic characteristics for a 1000 kWe pilot plant in Nio, Kagawa, Japan, constructed in 1980 are given.

  2. Effect of an alternate winglet on the pressure and spanwise load distributions of a first generation jet transport wing

    NASA Technical Reports Server (NTRS)

    Montoya, L. C.; Flechner, S. G.; Jacobs, P. F.

    1978-01-01

    Pressure and spanwise load distributions on a first-generation jet transport semispan model at subsonic speeds are presented. The wind tunnel data were measured for the wing with and without an alternate winglet. The results show that the winglet affected outboard wing pressure distributions and increased the spanwise loads near the tip.

  3. Voltage control of a matrix converter as the interface medium for a distributed generation unit

    NASA Astrophysics Data System (ADS)

    Gao, Fang

    This thesis proposes and investigates application of a three-phase AC-AC Matrix Converter (MC), as an alternative to the conventional AC-DC-AC converter system, to interface a Micro-Turbine-Generator (MTG) unit as a Distributed Generation (DG) unit to a utility distribution grid. As compared with a conventional AC-DC-AC converter system, lack of storage elements in a MC results in a stronger coupling and interactions between the AC sides of the MC and thus necessitates more stringent control of the MC to prevent/mitigate such effects. This thesis develops a novel dynamic model of the MC to analytically investigate and quantify the interaction phenomenon and design controllers of the MC. This thesis introduces a novel voltage control strategy for the MC to enable operation of a MC-interfaced MTG (MTG-MC) unit in (i) a grid-connected mode, (ii) an autonomous (islanded) mode, and (iii) transition between the two modes. The control strategy also provides an inherent islanding detection method without non-detection zone, and disturbance ride-through capability. The proposed voltage controller is intended for operation of the MTG-MC unit under balanced grid/load conditions. The MC voltage controller is augmented with a negative-sequence current controller to enable the MTG-MC unit also to operate under unbalanced grid/load conditions as a DG unit. The studies reported in this thesis are based on eigen analyses of the overall system linearized dynamic model, in the MATLAB environment, and digital time-domain simulation studies of the system nonlinear model, in the PSCAD/EMTDC environment.

  4. Neutron Tomography Using Mobile Neutron Generators for Assessment of Void Distributions in Thermal Hydraulic Test Loops

    NASA Astrophysics Data System (ADS)

    Andersson, P.; Bjelkenstedt, T.; Sundén, E. Andersson; Sjöstrand, H.; Jacobsson-Svärd, S.

    Detailed knowledge of the lateral distribution of steam (void) and water in a nuclear fuel assembly is of great value for nuclear reactor operators and fuel manufacturers, with consequences for both reactor safety and economy of operation. Therefore, nuclear relevant two-phase flows are being studied at dedicated thermal-hydraulic test loop, using two-phase flow systems ranging from simplified geometries such as heated circular pipes to full scale mock-ups of nuclear fuel assemblies. Neutron tomography (NT) has been suggested for assessment of the lateral distribution of steam and water in such test loops, motivated by a good ability of neutrons to penetrate the metallic structures of metal pipes and nuclear fuel rod mock-ups, as compared to e.g. conventional X-rays, while the liquid water simultaneously gives comparatively good contrast. However, these stationary test loops require the measurement setup to be mobile, which is often not the case for NT setups. Here, it is acknowledged that fast neutrons of 14 MeV from mobile neutron generators constitute a viable option for a mobile NT system. We present details of the development of neutron tomography for this purpose at the division of Applied Nuclear Physics at Uppsala University. Our concept contains a portable neutron generator, exploiting the fusion reaction of deuterium and tritium, and a detector with plastic scintillator elements designed to achieveadequate spatial and energy resolution, all mounted in a light-weight frame without collimators or bulky moderation to allow for a mobile instrument that can be moved about the stationary thermal hydraulic test sections. The detector system stores event-to-event pulse-height information to allow for discrimination based on the energy deposition in the scintillator elements.

  5. Emission Measure Distribution and Heating of Two Active Region Cores

    NASA Technical Reports Server (NTRS)

    Tripathi, Durgesh; Klimchuk, James A.; Mason, Helen E.

    2011-01-01

    Using data from the Extreme-ultraviolet Imaging Spectrometer aboard Hinode, we have studied the coronal plasma in the core of two active regions. Concentrating on the area between opposite polarity moss, we found emission measure distributions having an approximate power-law form EM/T(exp 2.4) from log T = 5.55 up to a peak at log T = 6.57. The observations are explained extremely well by a simple nanoflare model. However, in the absence of additional constraints, the observations could possibly also be explained by steady heating.

  6. New method for generating breast models featuring glandular tissue spatial distribution

    NASA Astrophysics Data System (ADS)

    Paixão, L.; Oliveira, B. B.; Oliveira, M. A.; Teixeira, M. H. A.; Fonseca, T. C. F.; Nogueira, M. S.

    2016-02-01

    Mammography is the main radiographic technique used for breast imaging. A major concern with mammographic imaging is the risk of radiation-induced breast cancer due to the high sensitivity of breast tissue. The mean glandular dose (DG) is the dosimetric quantity widely accepted to characterize the risk of radiation induced cancer. Previous studies have concluded that DG depends not only on the breast glandular content but also on the spatial distribution of glandular tissue within the breast. In this work, a new method for generating computational breast models featuring skin composition and glandular tissue distribution from patients undergoing digital mammography is proposed. Such models allow a more accurate way of calculating individualized breast glandular doses taking into consideration the glandular tissue fraction. Sixteen breast models of four patients with different glandularity breasts were simulated and the results were compared with those obtained from recommended DG conversion factors. The results show that the internationally recommended conversion factors may be overestimating the mean glandular dose to less dense breasts and underestimating the mean glandular dose for denser breasts. The methodology described in this work constitutes a powerful tool for breast dosimetry, especially for risk studies.

  7. Random bit generation at tunable rates using a chaotic semiconductor laser under distributed feedback.

    PubMed

    Li, Xiao-Zhou; Li, Song-Sui; Zhuang, Jun-Ping; Chan, Sze-Chun

    2015-09-01

    A semiconductor laser with distributed feedback from a fiber Bragg grating (FBG) is investigated for random bit generation (RBG). The feedback perturbs the laser to emit chaotically with the intensity being sampled periodically. The samples are then converted into random bits by a simple postprocessing of self-differencing and selecting bits. Unlike a conventional mirror that provides localized feedback, the FBG provides distributed feedback which effectively suppresses the information of the round-trip feedback delay time. Randomness is ensured even when the sampling period is commensurate with the feedback delay between the laser and the grating. Consequently, in RBG, the FBG feedback enables continuous tuning of the output bit rate, reduces the minimum sampling period, and increases the number of bits selected per sample. RBG is experimentally investigated at a sampling period continuously tunable from over 16 ns down to 50 ps, while the feedback delay is fixed at 7.7 ns. By selecting 5 least-significant bits per sample, output bit rates from 0.3 to 100 Gbps are achieved with randomness examined by the National Institute of Standards and Technology test suite.

  8. Quantification of collagen distributions in rat hyaline and fibro cartilages based on second harmonic generation imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Xiaoqin; Liao, Chenxi; Wang, Zhenyu; Zhuo, Shuangmu; Liu, Wenge; Chen, Jianxin

    2016-10-01

    Hyaline cartilage is a semitransparent tissue composed of proteoglycan and thicker type II collagen fibers, while fibro cartilage large bundles of type I collagen besides other territorial matrix and chondrocytes. It is reported that the meniscus (fibro cartilage) has a greater capacity to regenerate and close a wound compared to articular cartilage (hyaline cartilage). And fibro cartilage often replaces the type II collagen-rich hyaline following trauma, leading to scar tissue that is composed of rigid type I collagen. The visualization and quantification of the collagen fibrillar meshwork is important for understanding the role of fibril reorganization during the healing process and how different types of cartilage contribute to wound closure. In this study, second harmonic generation (SHG) microscope was applied to image the articular and meniscus cartilage, and textural analysis were developed to quantify the collagen distribution. High-resolution images were achieved based on the SHG signal from collagen within fresh specimens, and detailed observations of tissue morphology and microstructural distribution were obtained without shrinkage or distortion. Textural analysis of SHG images was performed to confirm that collagen in fibrocartilage showed significantly coarser compared to collagen in hyaline cartilage (p < 0.01). Our results show that each type of cartilage has different structural features, which may significantly contribute to pathology when damaged. Our findings demonstrate that SHG microscopy holds potential as a clinically relevant diagnostic tool for imaging degenerative tissues or assessing wound repair following cartilage injury.

  9. Diagnostic probes for particle and molecule distributions in laser-generated plumes

    SciTech Connect

    Kimbrell, S.M.

    1990-10-17

    Laser microprobe analysis (LMA) offers good spatial and depth resolution for solid sampling of virtually any material. Coupled with numerous optical spectroscopic and mass spectrometric detection methods, LMA is a powerful analytical tool. Yet, fundamental understanding of the interaction between the laser and the sample surface leading to the formation of the high temperature plasma (plume) is far from complete. To better understand the process of plume formation, an imaging method based on acousto-optic laser beam deflection has been coupled with light scattering methods and absorption methods to record temporal and spatial maps of the particle and molecule distributions in the plume with good resolution. Because particles can make up a major fraction of the vaporized material under certain operating conditions, they can reflect a large loss of atomic signal for elemental analysis, even when using auxiliary excitation to further vaporized the particles. Characterization of the particle size distributions in plumes should provide insight into the vaporization process and information necessary for studies of efficient particle transfer. Light scattering methods for particle size analysis based on the Mie Theory are used to determine the size of particles in single laser-generated plumes. The methods used, polarization ratio method and dissymmetry ratio method, provide good estimates of particle size with good spatial and temporal resolution for this highly transient system. Large particles, on the order of 0.02-0.2{mu}m in radius, were observed arising directly from the sample surface and from condensation.

  10. PV Ramping in a Distributed Generation Environment: A Study Using Solar Measurements; Preprint

    SciTech Connect

    Sengupta, M.; Keller, J.

    2012-06-01

    Variability in Photovoltaic (PV) generation resulting from variability in the solar radiation over the PV arrays is a topic of continuing concern for those involved with integrating renewables onto existing electrical grids. The island of Lanai, Hawaii is an extreme example of the challenges that integrators will face due to the fact that it is a small standalone grid. One way to study this problem is to take high-resolution solar measurements in multiple locations and model simultaneous PV production for various sizes at those locations. The National Renewable Energy Laboratory (NREL) collected high-resolution solar data at four locations on the island where proposed PV plants will be deployed in the near future. This data set provides unique insight into how the solar radiation may vary between points that are proximal in distance, but diverse in weather, due to the formation of orographic clouds in the center of the island. Using information about each proposed PV plant size, power output was created at high resolution. The team analyzed this output to understand power production ramps at individual locations and the effects of aggregating the production from all four locations. Hawaii is a unique environment, with extremely variable events occurring on a daily basis. This study provided an excellent opportunity for understanding potential worst-case scenarios for PV ramping. This paper provides an introduction to the datasets that NREL collected over a year and a comprehensive analysis of PV variability in a distributed generation scenario.

  11. Analysis of THz generation through the asymmetry of photoelectron angular distributions

    NASA Astrophysics Data System (ADS)

    Zhou, Zhaoyan; Wang, Xu; Lin, C. D.

    2017-03-01

    We analyze the mechanism of THz generation in a gas medium with intense two-color infrared lasers pulses. The dependence of the amplitude of THz emission on the relative phase between the fundamental color (800 nm) and its second harmonic (400 nm) is shown to be identical to the residual current as well as to the asymmetry of the above-threshold-ionization (ATI) photoelectrons along the left versus the right side of the linear polarization axis of the laser, thus confirming the validity of the semiclassical photocurrent model for the THz emission. We further analyze the even vs odd angular momentum distributions of the ATI electrons. The degree of overlap between the even-parity dominant electrons and the odd-parity dominant electrons within each ATI peak determines the strength of the THz emission, thus favoring the model that THz is generated through free-free transitions in the laser field. A model is also provided to obtain the same phase dependence as the four-wave mixing model.

  12. Generation and Validation of Spatial Distribution of Hourly Wind Speed Time-Series using Machine Learning

    NASA Astrophysics Data System (ADS)

    Veronesi, F.; Grassi, S.

    2016-09-01

    Wind resource assessment is a key aspect of wind farm planning since it allows to estimate the long term electricity production. Moreover, wind speed time-series at high resolution are helpful to estimate the temporal changes of the electricity generation and indispensable to design stand-alone systems, which are affected by the mismatch of supply and demand. In this work, we present a new generalized statistical methodology to generate the spatial distribution of wind speed time-series, using Switzerland as a case study. This research is based upon a machine learning model and demonstrates that statistical wind resource assessment can successfully be used for estimating wind speed time-series. In fact, this method is able to obtain reliable wind speed estimates and propagate all the sources of uncertainty (from the measurements to the mapping process) in an efficient way, i.e. minimizing computational time and load. This allows not only an accurate estimation, but the creation of precise confidence intervals to map the stochasticity of the wind resource for a particular site. The validation shows that machine learning can minimize the bias of the wind speed hourly estimates. Moreover, for each mapped location this method delivers not only the mean wind speed, but also its confidence interval, which are crucial data for planners.

  13. A new method to generate a high-resolution global distribution map of lake chlorophyll

    USGS Publications Warehouse

    Sayers, Michael J; Grimm, Amanda G.; Shuchman, Robert A.; Deines, Andrew M.; Bunnell, David B.; Raymer, Zachary B; Rogers, Mark W.; Woelmer, Whitney; Bennion, David; Brooks, Colin N.; Whitley, Matthew A.; Warner, David M.; Mychek-Londer, Justin G.

    2015-01-01

    A new method was developed, evaluated, and applied to generate a global dataset of growing-season chlorophyll-a (chl) concentrations in 2011 for freshwater lakes. Chl observations from freshwater lakes are valuable for estimating lake productivity as well as assessing the role that these lakes play in carbon budgets. The standard 4 km NASA OceanColor L3 chlorophyll concentration products generated from MODIS and MERIS sensor data are not sufficiently representative of global chl values because these can only resolve larger lakes, which generally have lower chl concentrations than lakes of smaller surface area. Our new methodology utilizes the 300 m-resolution MERIS full-resolution full-swath (FRS) global dataset as input and does not rely on the land mask used to generate standard NASA products, which masks many lakes that are otherwise resolvable in MERIS imagery. The new method produced chl concentration values for 78,938 and 1,074 lakes in the northern and southern hemispheres, respectively. The mean chl for lakes visible in the MERIS composite was 19.2 ± 19.2, the median was 13.3, and the interquartile range was 3.90–28.6 mg m−3. The accuracy of the MERIS-derived values was assessed by comparison with temporally near-coincident and globally distributed in situmeasurements from the literature (n = 185, RMSE = 9.39, R2 = 0.72). This represents the first global-scale dataset of satellite-derived chl estimates for medium to large lakes.

  14. Generation and distribution of PAHs in the process of medical waste incineration

    SciTech Connect

    Chen, Ying; Zhao, Rongzhi; Xue, Jun; Li, Jinhui

    2013-05-15

    Highlights: ► PAHs generation and distribution features of medical waste incineration are studied. ► More PAHs were found in fly ash than that in bottom ash. ► The highest proportion of PAHs consisted of the seven most carcinogenic ones. ► Increase of free oxygen molecule and burning temperature promote PAHs degradation. ► There is a moderate positive correlation between total PCDD/Fs and total PAHs. - Abstract: After the deadly earthquake on May 12, 2008 in Wenchuan county of China, several different incineration approaches were used for medical waste disposal. This paper investigates the generation properties of polycyclic aromatic hydrocarbons (PAHs) during the incineration. Samples were collected from the bottom ash in an open burning slash site, surface soil at the open burning site, bottom ash from a simple incinerator, bottom ash generated from the municipal solid waste (MSW) incinerator used for medical waste disposal, and bottom ash and fly ash from an incinerator exclusively used for medical waste. The species of PAHs were analyzed, and the toxicity equivalency quantities (TEQs) of samples calculated. Analysis results indicate that the content of total PAHs in fly ash was 1.8 × 10{sup 3} times higher than that in bottom ash, and that the strongly carcinogenic PAHs with four or more rings accumulated sensitively in fly ash. The test results of samples gathered from open burning site demonstrate that Acenaphthylene (ACY), Acenaphthene (ACE), Fluorene (FLU), Phenanthrene (PHE), Anthracene (ANT) and other PAHs were inclined to migrate into surrounding environment along air and surface watershed corridors, while 4- to 6-ring PAHs accumulated more likely in soil. Being consistent with other studies, it has also been confirmed that increases in both free oxygen molecules and combustion temperatures could promote the decomposition of polycyclic PAHs. In addition, without the influence of combustion conditions, there is a positive correlation between

  15. A Visual Basic Program to Generate Sediment Grain-Size Statistics and Extrapolate Particle Distributions

    NASA Astrophysics Data System (ADS)

    Poppe, L. J.; Eliason, A. E.; Hastings, M. E.

    2004-05-01

    Methods that describe and summarize grain-size distributions are important to geologists because of the large amount of information contained in textural data sets. Therefore, to facilitate reduction of sedimentologic data, we have written a computer program (GSSTAT) to generate grain-size statistics and extrapolate particle distributions. Our program is written in Microsoft Visual Basic 6.0, runs on Windows 95/98/ME/NT/2000/XP computers, provides a window to facilitate execution, and allows users to select options with mouse-click events or through interactive dialogue boxes. The program permits users to select output in either inclusive graphics or moment statistics, to extrapolate distributions to the colloidal-clay boundary by three methods, and to convert between frequency and cumulative frequency percentages. Detailed documentation is available within the program. Input files to the program must be comma-delimited ASCII text and have 20 fields that include: sample identifier, latitude, longitude, and the frequency or cumulative frequency percentages of the whole-phi fractions from 11 phi through -5 phi. Individual fields may be left blank, but the sum of the phi fractions must total 100% (+/- 0.2%). The program expects the first line of the input file to be a header showing attribute names; no embedded commas are allowed in any of the fields. Error messages warn the user of potential problems. The program generates an output file in the requested destination directory and allows the user to view results in a display window to determine the occurrence of errors. The output file has a header for its first line, but now has 34 fields; the original descriptor fields plus percentages of gravel, sand, silt and clay, statistics, classification, verbal descriptions, frequency or cumulative frequency percentages of the whole- phi fractions from 13 phi through -5 phi, and a field for error messages. If the user has selected extrapolation, the two additional phi

  16. Distributed Dynamic State Estimator, Generator Parameter Estimation and Stability Monitoring Demonstration

    SciTech Connect

    Meliopoulos, Sakis; Cokkinides, George; Fardanesh, Bruce; Hedrington, Clinton

    2013-12-31

    This is the final report for this project that was performed in the period: October1, 2009 to June 30, 2013. In this project, a fully distributed high-fidelity dynamic state estimator (DSE) that continuously tracks the real time dynamic model of a wide area system with update rates better than 60 times per second is achieved. The proposed technology is based on GPS-synchronized measurements but also utilizes data from all available Intelligent Electronic Devices in the system (numerical relays, digital fault recorders, digital meters, etc.). The distributed state estimator provides the real time model of the system not only the voltage phasors. The proposed system provides the infrastructure for a variety of applications and two very important applications (a) a high fidelity generating unit parameters estimation and (b) an energy function based transient stability monitoring of a wide area electric power system with predictive capability. Also the dynamic distributed state estimation results are stored (the storage scheme includes data and coincidental model) enabling an automatic reconstruction and “play back” of a system wide disturbance. This approach enables complete play back capability with fidelity equal to that of real time with the advantage of “playing back” at a user selected speed. The proposed technologies were developed and tested in the lab during the first 18 months of the project and then demonstrated on two actual systems, the USVI Water and Power Administration system and the New York Power Authority’s Blenheim-Gilboa pumped hydro plant in the last 18 months of the project. The four main thrusts of this project, mentioned above, are extremely important to the industry. The DSE with the achieved update rates (more than 60 times per second) provides a superior solution to the “grid visibility” question. The generator parameter identification method fills an important and practical need of the industry. The “energy function” based

  17. A Novel 500kW High-Speed Turbine PM Synchronous Generator Set for Distributed Power Generation

    NASA Astrophysics Data System (ADS)

    Wendt, Sven; Benecke, Frank; Güldner, Henry

    The paper presents a power generation system based on the cogeneration of heat and electricity with a novel high speed turbogenerator. The machine consists of a single stage steam turbine and a directly coupled permanent magnet synchronous generator in one constructional unit. A PWM IGBT rectifier is the load to the generator and a PWM IGBT three-phase four-wire inverter feeds the power into the low voltage mains. In order to increase the turbine efficiency at light load, variable speed operation of the turbogenerator is realized. Different control schemes for mains parallel operation and stand alone operation are presented. The control schemes allow for the use of a lookup table based control with a speed-power-characteristic or for the use of a maximum power point tracker. Measurement results from the successfully tested turbogenerator set are presented.

  18. Distributed Generation Potential of the U.S. CommercialSector

    SciTech Connect

    LaCommare, Kristina Hamachi; Edwards, Jennifer L.; Gumerman,Etan; Marnay, Chris

    2005-06-01

    Small-scale (100 kW-5 MW) on-site distributed generation (DG) economically driven by combined heat and power (CHP) applications and, in some cases, reliability concerns will likely emerge as a common feature of commercial building energy systems in developed countries over the next two decades. In the U.S., private and public expectations for this technology are heavily influenced by forecasts published by the Energy Information Administration (EIA), most notably the Annual Energy Outlook (AEO). EIA's forecasts are typically made using the National Energy Modeling System (NEMS), which has a forecasting module that predicts the penetration of several possible commercial building DG technologies over the period 2005-2025. Annual penetration is forecast by estimating the payback period for each technology, for each of a limited number of representative building types, for each of nine regions. This process results in an AEO2004 forecast deployment of about a total 3 GW of DG electrical generating capacity by 2025, which is only 0.25 percent of total forecast U.S. capacity. Analyses conducted using both the AEO2003 and AEO2004 versions of NEMS changes the baseline costs and performance characteristics of DG to reflect a world without U.S. Department of Energy (DOE) research into several thermal DG technologies, which is then compared to a case with enhanced technology representative of the successful achievement of DOE research goals. The net difference in 2025 DG penetration is dramatic using the AEO2003 version of NEMS, but much smaller in the AEO2004 version. The significance and validity of these contradictory results are discussed, and possibilities for improving estimates of commercial U.S. DG potential are explored.

  19. Femtosecond timing distribution and control for next generation accelerators and light sources

    SciTech Connect

    Chen, Li -Jin

    2014-03-31

    Femtosecond Timing Distribution At LCLS Free-electron-lasers (FEL) have the capability of producing high photon flux from the IR to the hard x-ray wavelength range and to emit femtosecond and eventually even attosecond pulses. This makes them an ideal tool for fundamental as well as applied re-search. Timing precision at the Stanford Linear Coherent Light Source (LCLS) between the x-ray FEL (XFEL) and ultrafast optical lasers is currently no better than 100 fs RMS. Ideally this precision should be much better and could be limited only by the x-ray pulse duration, which can be as short as a few femtoseconds. An increasing variety of science problems involving electron and nuclear dynamics in chemical and material systems will become accessible as the timing improves to a few femtoseconds. Advanced methods of electron beam conditioning or pulse injection could allow the FEL to achieve pulse durations less than one femtosecond. The objective of the work described in this proposal is to set up an optical timing distribution system based on mode locked Erbium doped fiber lasers at LCLS facility to improve the timing precision in the facility and allow time stamping with a 10 fs precision. The primary commercial applications for optical timing distributions systems are seen in the worldwide accelerator facilities and next generation light sources community. It is reasonable to expect that at least three major XFELs will be built in the next decade. In addition there will be up to 10 smaller machines, such as FERMI in Italy and Maxlab in Sweden, plus the market for upgrading already existing facilities like Jefferson Lab. The total market is estimated to be on the order of a 100 Million US Dollars. The company owns the exclusive rights to the IP covering the technology enabling sub-10 fs synchronization systems. Testing this technology, which has set records in a lab environment, at LCLS, hence in a real world scenario, is an important corner stone of bringing the

  20. Size distributions of PM, carbons and PAHs emitted from a generator using blended fuels containing water.

    PubMed

    Tsai, Jen-Hsiung; Chen, Shui-Jen; Huang, Kuo-Lin; Lin, Wen-Yinn; Lee, Wen-Jhy; Hsieh, Lien-Te; Lin, Chih-Chung; Tsai, Chin-Cheng

    2015-12-01

    This investigation studied the size distributions of particulate matter (PM), particulate carbon, and polycyclic aromatic hydrocarbons (PAHs) that are emitted from a generator that is fueled by diesel that is blended with waste-edible-oil-biodiesel and water-containing acetone. PM samples were collected using a micro-orifice uniform deposit impactor (MOUDI) and a Nano-MOUDI (with aerodynamic diameters of 0.01-18 μm). The results reveal that waste-edible biodiesel blended with water-containing acetone (W5WA3 or W20WA3) at a load of 3 kW emitted lower ΣPM, ΣPM-EC, ΣPM-OC, ΣT-PAHs or ΣT-BaPeq concentrations than did D100, in all 13 particle size ranges, and these reductions of emissions of submicron particles exceeded 85%. Furthermore, W20WA3 emitted significantly lower concentrations of Total-PAHs and Total-BaPeq in four nano/ultrafine particle size ranges. Therefore, water-containing acetone biodieselhols can be utilized as alternatives to petroleum diesel as fuel to reduce the dangers to human health that are posed by emissions from diesel engines.

  1. An equatorially enhanced grid with smooth resolution distribution generated by a spring dynamics method

    NASA Astrophysics Data System (ADS)

    Iga, Shin-ichi

    2017-02-01

    An equatorially enhanced grid is applicable to atmospheric general circulation simulations with better representations of the cumulus convection active in the tropics. This study improved the topology of previously proposed equatorially enhanced grids (Iga, 2015) [1], which had extremely large grid intervals around the poles. The proposed grids in this study are of a triangular mesh and are generated by a spring dynamics method with stretching around singular points, which are connected to five or seven neighboring grid points. The latitudinal distribution of resolution is nearly proportional to the combination of the map factors of the Mercator, Lambert conformal conic, and polar stereographic projections. The resolution contrast between the equator and pole is 2.3 ∼ 4.5 for the sampled cases, which is much smaller than that for the LML grids. This improvement requires only a small amount of additional grid resources, less than 11% of the total. The proposed grids are also examined with shallow water tests, and were found to perform better than the previous LML grids.

  2. Computer-assisted mesh generation based on hydrological response units for distributed hydrological modeling

    NASA Astrophysics Data System (ADS)

    Sanzana, P.; Jankowfsky, S.; Branger, F.; Braud, I.; Vargas, X.; Hitschfeld, N.; Gironás, J.

    2013-08-01

    Distributed hydrological models rely on a spatial discretization composed of homogeneous units representing different areas within the catchment. Hydrological Response Units (HRUs) typically form the basis of such a discretization. HRUs are generally obtained by intersecting raster or vector layers of land uses, soil types, geology and sub-catchments. Polylines maps representing ditches and river drainage networks can also be used. However this overlapping may result in a mesh with numerical and topological problems not highly representative of the terrain. Thus, a pre-processing is needed to improve the mesh in order to avoid negative effects on the performance of the hydrological model. This paper proposes computer-assisted mesh generation tools to obtain a more regular and physically meaningful mesh of HRUs suitable for hydrologic modeling. We combined existing tools with newly developed scripts implemented in GRASS GIS. The developed scripts address the following problems: (1) high heterogeneity in Digital Elevation Model derived properties within the HRUs, (2) correction of concave polygons or polygons with holes inside, (3) segmentation of very large polygons, and (4) bad estimations of units' perimeter and distances among them. The improvement process was applied and tested using two small catchments in France. The improvement of the spatial discretization was further assessed by comparing the representation and arrangement of overland flow paths in the original and improved meshes. Overall, a more realistic physical representation was obtained with the improved meshes, which should enhance the computation of surface and sub-surface flows in a hydrologic model.

  3. Valuation-Based Framework for Considering Distributed Generation Photovoltaic Tariff Design: Preprint

    SciTech Connect

    Zinaman, O. R.; Darghouth, N. R.

    2015-02-01

    While an export tariff is only one element of a larger regulatory framework for distributed generation, we choose to focus on tariff design because of the significant impact this program design component has on the various flows of value among power sector stakeholders. In that context, this paper is organized into a series of steps that can be taken during the design of a DGPV export tariff design. To that end this paper outlines a holistic, high-level approach to the complex undertaking of DGPV tariff design, the crux of which is an iterative cost-benefit analysis process. We propose a multi-step progression that aims to promote transparent, focused, and informed dialogue on CBA study methodologies and assumptions. When studies are completed, the long-run marginal avoided cost of the DGPV program should be compared against the costs imposed on utilities and non-participating customers, recognizing that these can be defined differently depending on program objectives. The results of this comparison can then be weighed against other program objectives to formulate tariff options. Potential changes to tariff structures can be iteratively fed back into established analytical tools to inform further discussions.

  4. Metal concentrations and distribution in paint waste generated during bridge rehabilitation in New York State.

    PubMed

    Shu, Zhan; Axe, Lisa; Jahan, Kauser; Ramanujachary, Kandalam V; Kochersberger, Carl

    2015-09-01

    Between 1950 and 1980, lead and chromium along with other metals have been used in paint coatings to protect bridges from corrosion. In New York State with 4500 bridges in 11 Regions 2385 of the bridges have been rehabilitated and subsequently repainted after 1989 when commercial use of lead based paint was prohibited. The purpose of this research was to address the concentration and distribution of trace metals in the paint waste generated during bridge rehabilitation. Using hypothesis testing and stratified sampling theory, a representative sample size of 24 bridges from across the state was selected that resulted in 117 paint waste samples. Field portable X-ray fluorescence (FP-XRF) analysis revealed metal concentrations ranged from 5 to 168,090 mg kg(-1) for Pb, 49,367 to 799,210 mg kg(-1) for Fe, and 27 to 425,510 mg kg(-1) for Zn. Eighty percent of the samples exhibited lead concentrations greater than 5000 mg kg(-1). The elevated iron concentrations may be attributed to the application of steel grit as an abrasive blasting material routinely used by state Departments of Transportation in the paint removal process. Other metals including Ba and Cr were observed in the paint waste as well. As a result of the paint formulation, metals were found to be associated in the paint waste (Pb correlated with Cr (r=0.85)). The elevated metal concentrations observed raises concern over the potential impact of leaching from this waste stream.

  5. Single phase inverter for a three phase power generation and distribution system

    NASA Technical Reports Server (NTRS)

    Lindena, S. J.

    1976-01-01

    A breadboard design of a single-phase inverter with sinusoidal output voltage for a three-phase power generation and distribution system was developed. The three-phase system consists of three single-phase inverters, whose output voltages are connected in a delta configuration. Upon failure of one inverter the two remaining inverters will continue to deliver three-phase power. Parallel redundancy as offered by two three-phase inverters is substituted by one three-phase inverter assembly with high savings in volume, weight, components count and complexity, and a considerable increase in reliability. The following requirements must be met: (1) Each single-phase, current-fed inverter must be capable of being synchronized to a three-phase reference system such that its output voltage remains phaselocked to its respective reference voltage. (2) Each single-phase, current-fed inverter must be capable of accepting leading and lagging power factors over a range from -0.7 through 1 to +0.7.

  6. Generation and dose distribution measurement of flash x-ray in KALI-5000 system

    NASA Astrophysics Data System (ADS)

    Menon, Rakhee; Roy, Amitava; Mitra, S.; Sharma, A.; Mondal, J.; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.

    2008-10-01

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm2 current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO4:Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance ˜1/xn, where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  7. Generation and dose distribution measurement of flash x-ray in KALI-5000 system.

    PubMed

    Menon, Rakhee; Roy, Amitava; Mitra, S; Sharma, A; Mondal, J; Mittal, K C; Nagesh, K V; Chakravarthy, D P

    2008-10-01

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm(2) current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO(4):Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance approximately 1/x(n), where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  8. Rucio - The next generation of large scale distributed system for ATLAS Data Management

    NASA Astrophysics Data System (ADS)

    Garonne, V.; Vigne, R.; Stewart, G.; Barisits, M.; eermann, T. B.; Lassnig, M.; Serfon, C.; Goossens, L.; Nairz, A.; Atlas Collaboration

    2014-06-01

    Rucio is the next-generation Distributed Data Management (DDM) system benefiting from recent advances in cloud and "Big Data" computing to address HEP experiments scaling requirements. Rucio is an evolution of the ATLAS DDM system Don Quijote 2 (DQ2), which has demonstrated very large scale data management capabilities with more than 140 petabytes spread worldwide across 130 sites, and accesses from 1,000 active users. However, DQ2 is reaching its limits in terms of scalability, requiring a large number of support staff to operate and being hard to extend with new technologies. Rucio will deal with these issues by relying on a conceptual data model and new technology to ensure system scalability, address new user requirements and employ new automation framework to reduce operational overheads. We present the key concepts of Rucio, including its data organization/representation and a model of how to manage central group and user activities. The Rucio design, and the technology it employs, is described, specifically looking at its RESTful architecture and the various software components it uses. We show also the performance of the system.

  9. THE NEXT GENERATION ATLAS OF QUASAR SPECTRAL ENERGY DISTRIBUTIONS FROM RADIO TO X-RAYS

    SciTech Connect

    Shang Zhaohui; Li Jun; Xie Yanxia; Brotherton, Michael S.; Cales, Sabrina L.; Dale, Daniel A.; Runnoe, Jessie C.; Kelly, Benjamin J.; Wills, Beverley J.; Wills, D.; Green, Richard F.; Nemmen, Rodrigo S.; Ganguly, Rajib; Hines, Dean C.; Kriss, Gerard A.; Tang, Baitian

    2011-09-01

    We have produced the next generation of quasar spectral energy distributions (SEDs), essentially updating the work of Elvis et al. by using high-quality data obtained with several space- and ground-based telescopes, including NASA's Great Observatories. We present an atlas of SEDs of 85 optically bright, non-blazar quasars over the electromagnetic spectrum from radio to X-rays. The heterogeneous sample includes 27 radio-quiet and 58 radio-loud quasars. Most objects have quasi-simultaneous ultraviolet-optical spectroscopic data, supplemented with some far-ultraviolet spectra, and more than half also have Spitzer mid-infrared Infrared Spectrograph spectra. The X-ray spectral parameters are collected from the literature where available. The radio, far-infrared, and near-infrared photometric data are also obtained from either the literature or new observations. We construct composite SEDs for radio-loud and radio-quiet objects and compare these to those of Elvis et al., finding that ours have similar overall shapes, but our improved spectral resolution reveals more detailed features, especially in the mid- and near-infrared.

  10. Generation and dose distribution measurement of flash x-ray in KALI-5000 system

    SciTech Connect

    Menon, Rakhee; Roy, Amitava; Mitra, S.; Sharma, A.; Mondal, J.; Mittal, K. C.; Nagesh, K. V.; Chakravarthy, D. P.

    2008-10-15

    Flash x-ray generation studies have been carried out in KALI-5000 Pulse power system. The intense relativistic electron beam has been bombarded on a tantalum target at anode to produce flash x-ray via bremsstrahlung conversion. The typical electron beam parameter was 360 kV, 18 kA, and 100 ns, with a few hundreds of A/cm{sup 2} current density. The x-ray dose has been measured with calcium sulfate:dysposium (CaSO{sub 4}:Dy) thermoluminescent dosimeter and the axial dose distribution has been characterized. It has been observed that the on axis dose falls of with distance {approx}1/x{sup n}, where n varies from 1.8 to 1.85. A maximum on axis dose of 46 mrad has been measured at 1 m distance from the source. A plastic scintillator with optical fiber coupled to a photomultiplier tube has been developed to measure the x-ray pulse width. The typical x-ray pulse width varied from 50 to 80 ns.

  11. The Case for Natural Gas Fueled Solid Oxide Fuel Cell Power Systems for Distributed Generation

    SciTech Connect

    Chick, Lawrence A.; Weimar, Mark R.; Whyatt, Greg A.; Powell, Michael R.

    2015-02-01

    Natural-gas-fueled solid oxide fuel cell (NGSOFC) power systems yield electrical conversion efficiencies exceeding 60% and may become a viable alternative for distributed generation (DG) if stack life and manufacturing economies of scale can be realized. Currently, stacks last approximately 2 years and few systems are produced each year because of the relatively high cost of electricity from the systems. If mass manufacturing (10,000 units per year) and a stack life of 15 years can be reached, the cost of electricity from an NGSOFC system is estimated to be about 7.7 ¢/kWh, well within the price of commercial and residential retail prices at the national level (9.9-10¢/kWh and 11-12 ¢/kWh, respectively). With an additional 5 ¢/kWh in estimated additional benefits from DG, NGSOFC could be well positioned to replace the forecasted 59-77 gigawatts of capacity loss resulting from coal plant closures due to stricter emissions regulations and low natural gas prices.

  12. Integrated Simulation Development and Decision Support Tool-Set for Utility Market and Distributed Solar Power Generation Electricore, Inc.

    SciTech Connect

    Daye, Tony

    2013-09-30

    This project will enable utilities to develop long-term strategic plans that integrate high levels of renewable energy generation, and to better plan power system operations under high renewable penetration. The program developed forecast data streams for decision support and effective integration of centralized and distributed solar power generation in utility operations. This toolset focused on real time simulation of distributed power generation within utility grids with the emphasis on potential applications in day ahead (market) and real time (reliability) utility operations. The project team developed and demonstrated methodologies for quantifying the impact of distributed solar generation on core utility operations, identified protocols for internal data communication requirements, and worked with utility personnel to adapt the new distributed generation (DG) forecasts seamlessly within existing Load and Generation procedures through a sophisticated DMS. This project supported the objectives of the SunShot Initiative and SUNRISE by enabling core utility operations to enhance their simulation capability to analyze and prepare for the impacts of high penetrations of solar on the power grid. The impact of high penetration solar PV on utility operations is not only limited to control centers, but across many core operations. Benefits of an enhanced DMS using state-of-the-art solar forecast data were demonstrated within this project and have had an immediate direct operational cost savings for Energy Marketing for Day Ahead generation commitments, Real Time Operations, Load Forecasting (at an aggregate system level for Day Ahead), Demand Response, Long term Planning (asset management), Distribution Operations, and core ancillary services as required for balancing and reliability. This provided power system operators with the necessary tools and processes to operate the grid in a reliable manner under high renewable penetration.

  13. Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity

    SciTech Connect

    Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

    2007-04-03

    Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  14. Generation of initial Vlasov distributions for simulation of charged particle beams with high space-charge intensity

    SciTech Connect

    Lund, S M; Kikuchi, T; Davidson, R C

    2007-04-12

    Self-consistent Vlasov simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel, both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of distributions commonly in use as initial Vlasov distributions in simulations of beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

  15. Next Generation Workload Management System For Big Data on Heterogeneous Distributed Computing

    NASA Astrophysics Data System (ADS)

    Klimentov, A.; Buncic, P.; De, K.; Jha, S.; Maeno, T.; Mount, R.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Porter, R. J.; Read, K. F.; Vaniachine, A.; Wells, J. C.; Wenaus, T.

    2015-05-01

    The Large Hadron Collider (LHC), operating at the international CERN Laboratory in Geneva, Switzerland, is leading Big Data driven scientific explorations. Experiments at the LHC explore the fundamental nature of matter and the basic forces that shape our universe, and were recently credited for the discovery of a Higgs boson. ATLAS and ALICE are the largest collaborations ever assembled in the sciences and are at the forefront of research at the LHC. To address an unprecedented multi-petabyte data processing challenge, both experiments rely on a heterogeneous distributed computational infrastructure. The ATLAS experiment uses PanDA (Production and Data Analysis) Workload Management System (WMS) for managing the workflow for all data processing on hundreds of data centers. Through PanDA, ATLAS physicists see a single computing facility that enables rapid scientific breakthroughs for the experiment, even though the data centers are physically scattered all over the world. The scale is demonstrated by the following numbers: PanDA manages O(102) sites, O(105) cores, O(108) jobs per year, O(103) users, and ATLAS data volume is O(1017) bytes. In 2013 we started an ambitious program to expand PanDA to all available computing resources, including opportunistic use of commercial and academic clouds and Leadership Computing Facilities (LCF). The project titled ‘Next Generation Workload Management and Analysis System for Big Data’ (BigPanDA) is funded by DOE ASCR and HEP. Extending PanDA to clouds and LCF presents new challenges in managing heterogeneity and supporting workflow. The BigPanDA project is underway to setup and tailor PanDA at the Oak Ridge Leadership Computing Facility (OLCF) and at the National Research Center "Kurchatov Institute" together with ALICE distributed computing and ORNL computing professionals. Our approach to integration of HPC platforms at the OLCF and elsewhere is to reuse, as much as possible, existing components of the PanDA system. We

  16. Next Generation Workload Management System For Big Data on Heterogeneous Distributed Computing

    SciTech Connect

    Klimentov, A.; Buncic, P.; De, K.; Jha, S.; Maeno, T.; Mount, R.; Nilsson, P.; Oleynik, D.; Panitkin, S.; Petrosyan, A.; Porter, R. J.; Read, K. F.; Vaniachine, A.; Wells, J. C.; Wenaus, T.

    2015-05-22

    The Large Hadron Collider (LHC), operating at the international CERN Laboratory in Geneva, Switzerland, is leading Big Data driven scientific explorations. Experiments at the LHC explore the fundamental nature of matter and the basic forces that shape our universe, and were recently credited for the discovery of a Higgs boson. ATLAS and ALICE are the largest collaborations ever assembled in the sciences and are at the forefront of research at the LHC. To address an unprecedented multi-petabyte data processing challenge, both experiments rely on a heterogeneous distributed computational infrastructure. The ATLAS experiment uses PanDA (Production and Data Analysis) Workload Management System (WMS) for managing the workflow for all data processing on hundreds of data centers. Through PanDA, ATLAS physicists see a single computing facility that enables rapid scientific breakthroughs for the experiment, even though the data centers are physically scattered all over the world. The scale is demonstrated by the following numbers: PanDA manages O(102) sites, O(105) cores, O(108) jobs per year, O(103) users, and ATLAS data volume is O(1017) bytes. In 2013 we started an ambitious program to expand PanDA to all available computing resources, including opportunistic use of commercial and academic clouds and Leadership Computing Facilities (LCF). The project titled 'Next Generation Workload Management and Analysis System for Big Data' (BigPanDA) is funded by DOE ASCR and HEP. Extending PanDA to clouds and LCF presents new challenges in managing heterogeneity and supporting workflow. The BigPanDA project is underway to setup and tailor PanDA at the Oak Ridge Leadership Computing Facility (OLCF) and at the National Research Center "Kurchatov Institute" together with ALICE distributed computing and ORNL computing professionals. Our approach to integration of HPC platforms at the OLCF and elsewhere is to reuse, as much as

  17. Next Generation Workload Management System For Big Data on Heterogeneous Distributed Computing

    DOE PAGES

    Klimentov, A.; Buncic, P.; De, K.; ...

    2015-05-22

    The Large Hadron Collider (LHC), operating at the international CERN Laboratory in Geneva, Switzerland, is leading Big Data driven scientific explorations. Experiments at the LHC explore the fundamental nature of matter and the basic forces that shape our universe, and were recently credited for the discovery of a Higgs boson. ATLAS and ALICE are the largest collaborations ever assembled in the sciences and are at the forefront of research at the LHC. To address an unprecedented multi-petabyte data processing challenge, both experiments rely on a heterogeneous distributed computational infrastructure. The ATLAS experiment uses PanDA (Production and Data Analysis) Workload Managementmore » System (WMS) for managing the workflow for all data processing on hundreds of data centers. Through PanDA, ATLAS physicists see a single computing facility that enables rapid scientific breakthroughs for the experiment, even though the data centers are physically scattered all over the world. The scale is demonstrated by the following numbers: PanDA manages O(102) sites, O(105) cores, O(108) jobs per year, O(103) users, and ATLAS data volume is O(1017) bytes. In 2013 we started an ambitious program to expand PanDA to all available computing resources, including opportunistic use of commercial and academic clouds and Leadership Computing Facilities (LCF). The project titled 'Next Generation Workload Management and Analysis System for Big Data' (BigPanDA) is funded by DOE ASCR and HEP. Extending PanDA to clouds and LCF presents new challenges in managing heterogeneity and supporting workflow. The BigPanDA project is underway to setup and tailor PanDA at the Oak Ridge Leadership Computing Facility (OLCF) and at the National Research Center "Kurchatov Institute" together with ALICE distributed computing and ORNL computing professionals. Our approach to integration of HPC platforms at the OLCF and elsewhere is to reuse, as much as possible, existing components of the PanDA system

  18. Future prospects for ECR plasma generators with improved charge state distributions

    SciTech Connect

    Alton, G.D.; Liu, Y.

    1997-06-01

    The growing number and variety of fundamental, applied, and industrial uses for high intensity, high charge state ion beams continues to be the driving force behind efforts to develop Electron Cyclotron Resonance (ECR) ion sources with superior performance characteristics. Incumbent with the advent of sub-micron electronic devices and their fabrication has been the demand for improved process control and optimization. These demands have led to the development of methods for cleaning, chemical etching, and deposition of thin films based on the use of plasma devices including ECR sources. Despite the steady advance in the technology, ECR plasma heating has not yet reached its full potential in terms of charge state and intensity within a particular charge state, in part, because of the narrow band width, single-frequency microwave radiation commonly used to heat the plasma electrons. This heating technique, coupled with conventional minimum-B configuration magnetic fields used for confining the electrons, resulting in the formation of the thin, ECR surfaces within the plasma volumes of these sources. This report identifies fundamentally important methods for enhancing the performances of ECR plasma generators by transforming the ECR zones from surfaces to volumes. Two methods are readily available for increasing the sizes of these zones. These techniques include: (1) a tailored magnetic field configuration in combination with single-frequency microwave radiation to create a large uniformly distributed ECR volume and; (2) the use of broadband-frequency domain techniques derived from standard TWT technology, to transform the resonant plasma surfaces of traditional ECR ion sources into resonant plasma volumes.

  19. A Framework for the Generation and Dissemination of Drop Size Distribution (DSD) Characteristics Using Multiple Platforms

    NASA Technical Reports Server (NTRS)

    Wolf, David B.; Tokay, Ali; Petersen, Walt; Williams, Christopher; Gatlin, Patrick; Wingo, Mathew

    2010-01-01

    Proper characterization of the precipitation drop size distribution (DSD) is integral to providing realistic and accurate space- and ground-based precipitation retrievals. Current technology allows for the development of DSD products from a variety of platforms, including disdrometers, vertical profilers and dual-polarization radars. Up to now, however, the dissemination or availability of such products has been limited to individual sites and/or field campaigns, in a variety of formats, often using inconsistent algorithms for computing the integral DSD parameters, such as the median- and mass-weighted drop diameter, total number concentration, liquid water content, rain rate, etc. We propose to develop a framework for the generation and dissemination of DSD characteristic products using a unified structure, capable of handling the myriad collection of disdrometers, profilers, and dual-polarization radar data currently available and to be collected during several upcoming GPM Ground Validation field campaigns. This DSD super-structure paradigm is an adaptation of the radar super-structure developed for NASA s Radar Software Library (RSL) and RSL_in_IDL. The goal is to provide the DSD products in a well-documented format, most likely NetCDF, along with tools to ingest and analyze the products. In so doing, we can develop a robust archive of DSD products from multiple sites and platforms, which should greatly benefit the development and validation of precipitation retrieval algorithms for GPM and other precipitation missions. An outline of this proposed framework will be provided as well as a discussion of the algorithms used to calculate the DSD parameters.

  20. THE GALACTIC SPATIAL DISTRIBUTION OF OB ASSOCIATIONS AND THEIR SURROUNDING SUPERNOVA-GENERATED SUPERBUBBLES

    SciTech Connect

    Higdon, J. C.; Lingenfelter, R. E. E-mail: rlingenfelter@ucsd.edu

    2013-10-01

    The Galactic spatial distribution of OB associations and their surrounding superbubbles (SBs) reflect the distribution of a wide range of important processes in our Galaxy. In particular, it can provide a three-dimensional measure not only of the major source distribution of Galactic cosmic rays, but also the Galactic star formation distribution, the Lyman continuum ionizing radiation distribution, the core-collapse supernova distribution, the neutron star and stellar black hole production distribution, and the principal source distribution of freshly synthesized elements. Thus, we construct a three-dimensional spatial model of the massive-star distribution based primarily on the emission of the H II envelopes that surround the giant SBs and are maintained by the ionizing radiation of the embedded O stars. The Galactic longitudinal distribution of the 205 μm N II radiation, emitted by these H II envelopes, is used to infer the spatial distribution of SBs. We find that the Galactic SB distribution is dominated by the contribution of massive-star clusters residing in the spiral arms.

  1. Generations.

    PubMed

    Chambers, David W

    2005-01-01

    Groups naturally promote their strengths and prefer values and rules that give them an identity and an advantage. This shows up as generational tensions across cohorts who share common experiences, including common elders. Dramatic cultural events in America since 1925 can help create an understanding of the differing value structures of the Silents, the Boomers, Gen Xers, and the Millennials. Differences in how these generations see motivation and values, fundamental reality, relations with others, and work are presented, as are some applications of these differences to the dental profession.

  2. Diffraction patterns from holographic masks generated using combined axicon and helical phase distributions

    NASA Astrophysics Data System (ADS)

    Mihailescu, M.; Preda, L.; Kusko, C.; Scarlat, E. I.

    2015-02-01

    The diffraction patterns (DPs) from helical phase distributions were intensively studied due to their peculiar capability of carrying orbital angular momentum. In the present study, we investigated the combination between a helical phase distribution and another distribution: axicon in our case. Such phase distributions were digitally embedded into holographic masks (HMs). The reconstruction step is performed by simulating the propagation through these HMs, using scalar diffraction theory, Fraunhofer approximation. The spatial intensity arrangement of the DPs is investigated linked with the radial and azimuthal constructive parameters values of the diffractive phase structures embedded in the HMs and transferred in these DPs. Keywords: helical phase distribution

  3. Reduced resilience of a globally distributed coccolithophore to ocean acidification: Confirmed up to 2000 generations.

    PubMed

    Jin, Peng; Gao, Kunshan

    2016-02-15

    Ocean acidification (OA), induced by rapid anthropogenic CO2 rise and its dissolution in seawater, is known to have consequences for marine organisms. However, knowledge on the evolutionary responses of phytoplankton to OA has been poorly studied. Here we examined the coccolithophore Gephyrocapsa oceanica, while growing it for 2000 generations under ambient and elevated CO2 levels. While OA stimulated growth in the earlier selection period (from generations ~700 to ~1550), it reduced it in the later selection period up to 2000 generations. Similarly, stimulated production of particulate organic carbon and nitrogen reduced with increasing selection period and decreased under OA up to 2000 generations. The specific adaptation of growth to OA disappeared in generations 1700 to 2000 when compared with that at 1000 generations. Both phenotypic plasticity and fitness decreased within selection time, suggesting that the species' resilience to OA decreased after 2000 generations under high CO2 selection.

  4. PhotoVoltaic distributed generation for Lanai power grid real-time simulation and control integration scenario.

    SciTech Connect

    Robinett, Rush D., III; Kukolich, Keith; Wilson, David Gerald; Schenkman, Benjamin L.

    2010-06-01

    This paper discusses the modeling, analysis, and testing in a real-time simulation environment of the Lanai power grid system for the integration and control of PhotoVoltaic (PV) distributed generation. The Lanai Island in Hawaii is part of the Hawaii Clean Energy Initiative (HCEI) to transition to 30% renewable green energy penetration by 2030. In Lanai the primary loads come from two Castle and Cook Resorts, in addition to residential needs. The total peak load profile is 12470 V, 5.5 MW. Currently there are several diesel generators that meet these loading requirements. As part of the HCEI, Lanai has initially installed 1.2 MW of PV generation. The goal of this study has been to evaluate the impact of the PV with respect to the conventional carbon-based diesel generation in real time simulation. For intermittent PV distributed generation, the overall stability and transient responses are investigated. A simple Lanai 'like' model has been developed in the Matlab/Simulink environment (see Fig. 1) and to accommodate real-time simulation of the hybrid power grid system the Opal-RT Technologies RT-Lab environment is used. The diesel generators have been modelled using the SimPowerSystems toolbox swing equations and a custom Simulink module has been developed for the High level PV generation. All of the loads have been characterized primarily as distribution lines with series resistive load banks with one VAR load bank. Three-phase faults are implemented for each bus. Both conventional and advanced control architectures will be used to evaluate the integration of the PV onto the current power grid system. The baseline numerical results include the stable performance of the power grid during varying cloud cover (PV generation ramping up/down) scenarios. The importance of assessing the real-time scenario is included.

  5. Spatial distribution of the interacting Waves' amplitudes under third harmonic generation in a negative-positive refractive medium

    NASA Astrophysics Data System (ADS)

    Ostroukhova, E. I.; Maimistov, A. I.

    2013-09-01

    The process of third harmonic generation in a cubically nonlinear medium that is negatively refractive at the fundamental frequency and positively refractive at the third harmonic frequency is considered. For the stationary case, the amplitude distribution was obtained for waves interacting inside a sample for different values of phase mismatch. In the periodic regime of generation, it is shown that the amplitude of the fundamental wave inside the medium can exceed its value at the input, which is impossible in the standard case of harmonic generation in a medium positively refractive at both frequencies. The influence of energy losses in the sample on the spatial distribution of waves' amplitudes of both frequencies has been studied.

  6. Integration of Renewables Via Demand Management: Highly Dispatchable and Distributed Demand Response for the Integration of Distributed Generation

    SciTech Connect

    2012-02-11

    GENI Project: AutoGrid, in conjunction with Lawrence Berkeley National Laboratory and Columbia University, will design and demonstrate automated control software that helps manage real-time demand for energy across the electric grid. Known as the Demand Response Optimization and Management System - Real-Time (DROMS-RT), the software will enable personalized price signal to be sent to millions of customers in extremely short timeframes—incentivizing them to alter their electricity use in response to grid conditions. This will help grid operators better manage unpredictable demand and supply fluctuations in short time-scales —making the power generation process more efficient and cost effective for both suppliers and consumers. DROMS-RT is expected to provide a 90% reduction in the cost of operating demand response and dynamic pricing Projects in the U.S.

  7. A novel aerosol generator for homogenous distribution of powder over the lungs after pulmonary administration to small laboratory animals.

    PubMed

    Tonnis, Wouter F; Bagerman, Marieke; Weij, Michel; Sjollema, Jelmer; Frijlink, Henderik W; Hinrichs, Wouter L J; de Boer, Anne H

    2014-11-01

    To evaluate powder formulations for pulmonary administration in pre-clinic research, the powder should be administered to the lungs of small laboratory animals. To do so properly, a device is needed that generates particles small enough to reach deep into the lungs. In this study a newly developed aerosol generator was tested for pulmonary administration of powder to the lungs of mice and its performance was compared to the only currently available device, the Penn-Century insufflator. Results showed that both devices generated powder particles of approximately the same size distribution, but the fine particle fraction needed for deep lung administration was strongly improved when the aerosol generator was used.Imaging studies in mice showed that powder particles from the aerosol generator deposited into the deep lung, where powder from the Penn-Century insufflator did not reach further than the conducting airways.Furthermore, powder administered by using the aerosol generator was more homogenously distributed over the five individual lungs lobes than powder administrated by using the Penn-Century insufflator.

  8. The Generation of Kappa distributions At Perpendicular Shocks And The Heliospheric Termination Shock

    NASA Astrophysics Data System (ADS)

    Zank, G. P.

    2015-12-01

    Although wave-particle interactions may maintain a pre-existing kappa distribution throughout the solar wind once formed, an important question is to identify the origin of a quasi-kappa distribution. It transpires that the dissipation mechanism at quasi-perpendicular shocks and the so-called injection problem at shock waves may be of particular relevance to the formation of initial quasi-kappa distributions throughout the solar wind. In particular, the question of how particles are injected into the diffusive shock acceleration (DSA) mechanism at a perpendicular shock can be addressed on the basis of a kappa distribution. We discuss briefly the possible formation of a kappa distribution at interplanetary shocks and show how this is then accelerated at a quasi-perpendicular shock. These results are related to observed energetic particle spectra downstream of an interplanetary shock. The related question of the dissipation mechanism at the quasi-perpendicular heliospheric termination shock is discussed, focusing particularly in the important role of the pickup ion distribution upstream and downstream of the heliospheric termination shock. We show that the downstream proton distribution in the inner heliosheath closely resembles a kappa distribution.

  9. A Hybrid Computer Simulation to Generate the DNA Distribution of a Cell Population.

    ERIC Educational Resources Information Center

    Griebling, John L.; Adams, William S.

    1981-01-01

    Described is a method of simulating the formation of a DNA distribution, on which statistical results and experimentally measured parameters from DNA distribution and percent-labeled mitosis studies are combined. An EAI-680 and DECSystem-10 Hybrid Computer configuration are used. (Author/CS)

  10. Key distribution based on synchronization in bandwidth-enhanced random bit generators with dynamic post-processing.

    PubMed

    Xue, Chenpeng; Jiang, Ning; Qiu, Kun; Lv, Yunxin

    2015-06-01

    We propose and numerically demonstrate a new scheme for key distribution on the physical layer based on the chaos synchronization and physical random bit generation. In this scheme, two chaotic semiconductor lasers are commonly driven by a third semiconductor laser, their output chaotic signals are employed as the physical sources of the random bit generators (RBGs). Under symmetry operation scenario, the two RBGs are well synchronized and the random bits generated by them are used to generate identical secret keys for Alice and Bob by the way of a dynamic post-processing technology. The feasibility and security of the proposed scheme are investigated by testing the parameters mismatch tolerance and the sensitivity to the systematic noise. The numerical results indicate that the dynamic and unpredictable post-processing can provide a great enhancement for the security of the secret key distribution. The security of the proposed scheme mainly determined by the post-processing, not confidential source, which provides a new potential way for implementing high-speed secure secret key distribution.

  11. A strategy for the generation, characterization and distribution of animal models by The Michael J. Fox Foundation for Parkinson's Research.

    PubMed

    Baptista, Marco A S; Dave, Kuldip D; Sheth, Niketa P; De Silva, Shehan N; Carlson, Kirsten M; Aziz, Yasmin N; Fiske, Brian K; Sherer, Todd B; Frasier, Mark A

    2013-11-01

    Progress in Parkinson's disease (PD) research and therapeutic development is hindered by many challenges, including a need for robust preclinical animal models. Limited availability of these tools is due to technical hurdles, patent issues, licensing restrictions and the high costs associated with generating and distributing these animal models. Furthermore, the lack of standardization of phenotypic characterization and use of varying methodologies has made it difficult to compare outcome measures across laboratories. In response, The Michael J. Fox Foundation for Parkinson's Research (MJFF) is directly sponsoring the generation, characterization and distribution of preclinical rodent models, enabling increased access to these crucial tools in order to accelerate PD research. To date, MJFF has initiated and funded the generation of 30 different models, which include transgenic or knockout models of PD-relevant genes such as Park1 (also known as Park4 and SNCA), Park8 (LRRK2), Park7 (DJ-1), Park6 (PINK1), Park2 (Parkin), VPS35, EiF4G1 and GBA. The phenotypic characterization of these animals is performed in a uniform and streamlined manner at independent contract research organizations. Finally, MJFF created a central repository at The Jackson Laboratory (JAX) that houses both non-MJFF and MJFF-generated preclinical animal models. Funding from MJFF, which subsidizes the costs involved in transfer, rederivation and colony expansion, has directly resulted in over 2500 rodents being distributed to the PD community for research use.

  12. Relationship between pressure fluctuations and generation of organic pollutants with different particle size distributions in a fluidized bed incinerator.

    PubMed

    Lin, Chiou-Liang; Wey, Ming-Yen; Cheng, Han-Tsung

    2004-09-01

    The hydrodynamic behaviors of fluidization perhaps significantly influence the uniformity of fluidization in fluidized bed incinerator. Good uniformity of fluidization expressed the air across uniformly through the bed and the particles being distributed well in the fluid stream. The aggregates, flocs and channels of particles do not happen during fluidization. The Good uniformity will maintain high heat and mass distribution to improve reaction efficiency. These parameters include the height of static bed, gas velocity, mixing and distribution of bed particle, which have rarely been studied in previous investigations. Consequently, this study examines how the hydrodynamic parameters affect the generation of organic pollutants (BTEXs and PAHs) during incineration. The statistical and power spectral analysis of the measured pressure fluctuation during incineration are used to elucidate the relationship between behaviors of fluidization and generation of pollutants during incineration. Experimental results show the organic concentration does not increase with uniformity of fluidization decreasing. The reason may be the explosion of the gas and the consequent thermal shock destroy the coalescent bubbles to form small bubbles again and enhance the efficiency of transfer of oxygen to increase combustion efficiency. Additionally, the mean amplitude and fluidized index of pressure fluctuation similarly vary with the concentration of organic pollutants. These two indices can be used to assess the efficiency of combustion. The four particle size distributions could be divided into two groups by statistical analysis. The Gaussian and narrow distributions belong to one group and the binary and flat the other. The organic concentration of the Gaussian and narrow distributions are lower than that of the other distributions. Consequently, the bed materials should maintain narrow or Gaussian distributions to maintain a good combustion efficiency during incineration.

  13. Optimization of Fin Distribution to Improve the Temperature Uniformity of a Heat Exchanger in a Thermoelectric Generator

    NASA Astrophysics Data System (ADS)

    Wang, Yiping; Wu, Cheng; Tang, Zebo; Yang, Xue; Deng, Yadong; Su, Chuqi

    2015-06-01

    Thermoelectric generators (TEGs) are currently a topic of interest for energy recovery in vehicles. By applying TEGs to the outside surface of the exhaust tailpipe, a small amount of electrical power can be generated because of the temperature difference between the hot exhaust gases and the automobile coolant. The amount of power is anticipated to be a few hundred watts based on the expected temperature difference and the properties of the thermoelectric materials used in TEGs. It is well know that, for thermoelectric exhaust energy recovery, the temperature uniformity of the heat exchangers has a strong influence on the electric power generation. In the current research, the temperature uniformity of a heat exchanger was improved by optimizing the fin distribution to maximize the electric power generated for a given vehicle TEG. A computational fluid dynamics (CFD) model of the heat exchanger was constructed to assess the influence of different fin distributions on the temperature uniformity and the pressure drop in the exhaust system. For the fin distributions, four factors were considered: the length of, spacing between, angle of, and thickness of the fins. Based on these four factors, a design of experiments study using the orthogonal experimental method was conducted to analyze the sensitivity to the design variables and build a database to set up a surrogate model using the Kriging response surface method. A multi-island genetic algorithm was used to optimize the fin distribution based on this surrogate model. To validate the accuracy of the CFD model, a generic heat exchanger module was manufactured and a related testbed constructed, then the temperature distribution on the surface of the exchanger was measured to compare with the results obtained by CFD.

  14. Interrupted: The roles of distributed effort and incubation in preventing fixation and generating problem solutions.

    PubMed

    Sio, Ut Na; Kotovsky, Kenneth; Cagan, Jonathan

    2016-12-27

    Fixation on inappropriate concepts is a key barrier to problem solving. Previous research has shown that continuous work is likely to cause repeated retrieval of those concepts, resulting in increased fixation. Accordingly, distributing effort across problems through multiple, brief, and interlaced sessions (distributed effort) should prevent such fixation and in turn enhance problem solving. This study examined whether distributed effort can provide an advantage for problem solving, particularly for problems that can induce fixation (Experiment 1), and whether and how incubation can be combined with distributed effort to further enhance performance (Experiment 2). Remote Associates Test (RAT) problems were used as the problem-solving tasks. Half of them (i.e., misleading RAT) were more likely to mislead individuals to fixate on incorrect associates than the other half. Experiments revealed a superiority of distributed over massed effort on misleading RAT performance and a differing time course of incubation for the massed and distributed groups. We conclude that distributed effort facilitates problem solving, most likely via overcoming fixation. Cognitive mechanisms other than the commonly posited forgetting of inappropriate ideas may occur during incubation to facilitate problem solving. The experiments in this article offer support for the occurrence of spreading activation during incubation.

  15. Distribution functions in plasmas generated by a volume source of fission fragments. [in nuclear pumped lasers

    NASA Technical Reports Server (NTRS)

    Deese, J. E.; Hassan, H. A.

    1979-01-01

    The role played by fission fragments and electron distribution functions in nuclear pumped lasers is considered and procedures for their calculations are outlined. The calculations are illustrated for a He-3/Xe mixture where fission is provided by the He-3(n,p)H-3 reaction. Because the dominant ion in the system depends on the Xe fraction, the distribution functions cannot be determined without the simultaneous consideration of a detailed kinetic model. As is the case for wall sources of fission fragments, the resulting plasmas are essentially thermal but the electron distribution functions are non-Maxwellian.

  16. Determination of Surface Stress Distributions in Steel Using Laser-Generated Surface Acoustic Waves

    NASA Astrophysics Data System (ADS)

    Shi; Yifei; Ni; Chenyin; Shen; Zhonghua; Ni; Xiaowu; Lu; Jian

    2008-05-01

    High frequency surface acoustic waves (SAWs) are excited by a pulsed laser and detected by a specially designed poly(vinylidene fluoride) (PVDF) transducer to investigate surface stress distribution. Two kinds of stressed surfaces are examined experimentally. One is a steel plate elastically deformed under simple bending forces, where the surface stress varies slowly. The other is a welded steel plate for which the surface stress varies very rapidly within a small area near the welding seam. Applying a new signal processing method developed from correlation technique, the velocity distribution of the SAWs, which reflects the stress distribution, is obtained in these two samples with high resolution.

  17. SADDE (Scaled Absorbed Dose Distribution Evaluator): A code to generate input for VARSKIN

    SciTech Connect

    Reece, W.D.; Miller, S.D.; Durham, J.S.

    1989-01-01

    The VARSKIN computer code has been limited to the isotopes for which the scaled absorbed dose distributions were provided by the Medical Internal Radiation Dose (MIRD) Committee or to data that could be interpolated from isotopes that had similar spectra. This document describes the methodology to calculate the scaled absorbed dose distribution data for any isotope (including emissions by the daughter isotopes) and its implementation by a computer code called SADDE (Scaled Absorbed Dose Distribution Evaluator). The SADDE source code is provided along with input examples and verification calculations. 10 refs., 4 figs.

  18. Flow and Temperature Distribution Evaluation on Sodium Heated Large-sized Straight Double-wall-tube Steam Generator

    SciTech Connect

    Kisohara, Naoyuki; Moribe, Takeshi; Sakai, Takaaki

    2006-07-01

    The sodium heated steam generator (SG) being designed in the feasibility study on commercialized fast reactor cycle systems is a straight double-wall-tube type. The SG is large sized to reduce its manufacturing cost by economics of scale. This paper addresses the temperature and flow multi-dimensional distributions at steady state to obtain the prospect of the SG. Large-sized heat exchanger components are prone to have non-uniform flow and temperature distributions. These phenomena might lead to tube buckling or tube to tube-sheet junction failure in straight tube type SGs, owing to tubes thermal expansion difference. The flow adjustment devices installed in the SG are optimized to prevent these issues, and the temperature distribution properties are uncovered by analysis methods. The analysis model of the SG consists of two parts, a sodium inlet distribution plenum (the plenum) and a heat transfer tubes bundle region (the bundle). The flow and temperature distributions in the plenum and the bundle are evaluated by the three-dimensional code 'FLUENT' and the two dimensional thermal-hydraulic code 'MSG', respectively. The MSG code is particularly developed for sodium heated SGs in JAEA. These codes have revealed that the sodium flow is distributed uniformly by the flow adjustment devices, and that the lateral tube temperature distributions remain within the allowable temperature range for the structural integrity of the tubes and the tube to tube-sheet junctions. (authors)

  19. Energy distribution of runaway electrons generated by a nanosecond discharge in atmospheric-pressure air

    NASA Astrophysics Data System (ADS)

    Tarasenko, V. F.; Baksht, E. Kh.; Burachenko, A. G.; Kostyrya, I. D.; Lomaev, M. I.; Petin, V. K.; Rybka, D. V.; Shlyakhtun, S. V.

    2008-12-01

    The spectra of an ultrashort avalanche electron beam generated by a nanosecond discharge in atmospheric-pressure air were investigated. The temporal characteristics of the beam current pulses, gap voltage, and discharge current in a gas diode were measured with a time resolution of ˜0.1 ns. A simple technique was developed for recovering electron spectra from the curves of beam attenuation by aluminum foils. The effect of the cathode design, electrode gap length, and generator parameters on the electron spectra were studied using seven setups. It is shown that generation of electrons with anomalously high energies requires the use of cathodes with increased curvature radius.

  20. Energy distribution of runaway electrons generated by a nanosecond discharge in atmospheric-pressure air

    SciTech Connect

    Tarasenko, V. F.; Baksht, E. Kh.; Burachenko, A. G.; Kostyrya, I. D.; Lomaev, M. I.; Petin, V. K.; Rybka, D. V.; Shlyakhtun, S. V.

    2008-12-15

    The spectra of an ultrashort avalanche electron beam generated by a nanosecond discharge in atmospheric-pressure air were investigated. The temporal characteristics of the beam current pulses, gap voltage, and discharge current in a gas diode were measured with a time resolution of {approx}0.1 ns. A simple technique was developed for recovering electron spectra from the curves of beam attenuation by aluminum foils. The effect of the cathode design, electrode gap length, and generator parameters on the electron spectra were studied using seven setups. It is shown that generation of electrons with anomalously high energies requires the use of cathodes with increased curvature radius.

  1. Scheme for generating high-quality optical multicarrier for quantum key distribution wavelength division-multiplexing passive optical network

    NASA Astrophysics Data System (ADS)

    Zhu, Min; Li, Dawei

    2015-10-01

    We proposed and analyzed a scheme of generating an optical multicarrier using a linear optical modulator-based hybrid interferometer modulator and a dual parallel Mach-Zehnder modulator. Fifteen-tone comb lines within 0.5-dB spectral power variation are obtained; the side-mode suppression ratio is about 35 dB and the system is tolerant to radio-frequency phase differences. Some analysis on the noise characteristics and the impact of parameter drifting is also made. These features indicate that the proposed multicarrier generator is a good multiwavelength source for quantum key distribution wavelength division-multiplexing passive optical networks.

  2. Optimization of a stand-alone Solar PV-Wind-DG Hybrid System for Distributed Power Generation at Sagar Island

    NASA Astrophysics Data System (ADS)

    Roy, P. C.; Majumder, A.; Chakraborty, N.

    2010-10-01

    An estimation of a stand-alone solar PV and wind hybrid system for distributed power generation has been made based on the resources available at Sagar island, a remote area distant to grid operation. Optimization and sensitivity analysis has been made to evaluate the feasibility and size of the power generation unit. A comparison of the different modes of hybrid system has been studied. It has been estimated that Solar PV-Wind-DG hybrid system provides lesser per unit electricity cost. Capital investment is observed to be lesser when the system run with Wind-DG compared to Solar PV-DG.

  3. Performance Analysis of Positive-feedback-based Active Anti-islanding Schemes for Inverter-Based Distributed Generators

    SciTech Connect

    Du, Pengwei; Aponte, Erick E.; Nelson, J. Keith

    2010-06-14

    Recently proposed positive-feedback-based anti-islanding schemes (AI) are highly effective in preventing islanding without causing any degradation in power quality. This paper aims to analyze the performance of these schemes quantitatively in the context of the dynamic models of inverter-based distributed generators (DG). In this study, the characteristics of these active anti-islanding methods are discussed and design guidelines are derived.

  4. Generation of Some First-Order Autoregressive Markovian Sequences of Positive Random Variables with Given Marginal Distributions,

    DTIC Science & Technology

    1981-03-01

    LAWRANCE , P A LEWIS UNCLASSIFIED NWS55-81-003 NLm ’hEEEIIIIEEE mhhhhEEh EEEEEEEllEEEll 46 NPS55-81-003 NAVAL POSTGRADUATE SCHOOL Monterey, California D C...GENERATION OF SOME FIRST-ORDER AUTOREGRESSIVE MARKOVIAN SEQUENCES OF POSITIVE RANDOM VARIABLES WITH GIVEN MARGINAL DISTRIBUTIONS by A. J. Lawrance P. A... Lawrance University of Birmingham Birmingham, England P. A. W. Lewis, Professor Department of Operations Research Reviewed by: Released by: K. T

  5. Fundamental Characteristics of Laboratory Scale Model DC Microgrid to Exchange Electric Power from Distributed Generations installed in Residential Houses

    NASA Astrophysics Data System (ADS)

    Kakigano, Hiroaki; Hashimoto, Takuya; Matsumura, Yohei; Kurotani, Takashi; Iwamoto, Wataru; Miura, Yushi; Ise, Toshifumi; Momose, Toshinari; Hayakawa, Hideki

    DC microgrid is a novel power system using dc distribution in order to provide a super high quality power. This dc system is suitable for dc output type distributed generations and energy storages. In this research, we assumed one type of the dc microgrids for residential houses (apartment house or housing complex). Each residence has a distributed generation such as gas engine or fuel cell. Those cogenerations are connected to the dc power line, and the electricity from the generations can be shared among the residences. The hot water from the cogeneration is used in each residence. We constructed an experimental system based on this concept in our laboratory. We have studied the fundamental characteristics and the quality of the supplied power to the loads against several fluctuations or faults. Experimental results demonstrated that the system could supply high quality power to the loads against a sudden load variation and a voltage sag of the utility grid. Afterwards, we moved the experimental system to an experimental apartment house (NEXT21). We studied the quality of the supplying power by using practical power line, and confirmed that the system was also able to supply a power to home appliances stably.

  6. Utilizing Electric Vehicles to Assist Integration of Large Penetrations of Distributed Photovoltaic Generation Capacity

    SciTech Connect

    Tuffner, Francis K.; Chassin, Forrest S.; Kintner-Meyer, Michael CW; Gowri, Krishnan

    2012-11-30

    Executive Summary Introduction and Motivation This analysis provides the first insights into the leveraging potential of distributed photovoltaic (PV) technologies on rooftop and electric vehicle (EV) charging. Either of the two technologies by themselves - at some high penetrations – may cause some voltage control challenges or overloading problems, respectively. But when combined, there – at least intuitively – could be synergistic effects, whereby one technology mitigates the negative impacts of the other. High penetration of EV charging may overload existing distribution system components, most prominently the secondary transformer. If PV technology is installed at residential premises or anywhere downstream of the secondary transformer, it will provide another electricity source thus, relieving the loading on the transformers. Another synergetic or mitigating effect could be envisioned when high PV penetration reverts the power flow upward in the distribution system (from the homes upstream into the distribution system). Protection schemes may then no longer work and voltage violation (exceeding the voltage upper limited of the ANSI voltage range) may occur. In this particular situation, EV charging could absorb the electricity from the PV, such that the reversal of power flow can be reduced or alleviated. Given these potential mutual synergistic behaviors of PV and EV technologies, this project attempted to quantify the benefits of combining the two technologies. Furthermore, of interest was how advanced EV control strategies may influence the outcome of the synergy between EV charging and distributed PV installations. Particularly, Californian utility companies with high penetration of the distributed PV technology, who have experienced voltage control problems, are interested how intelligent EV charging could support or affect the voltage control

  7. Evaluation of Representative Smart Grid Investment Grant Project Technologies: Distributed Generation

    SciTech Connect

    Singh, Ruchi; Vyakaranam, Bharat GNVSR

    2012-02-14

    This document is one of a series of reports estimating the benefits of deploying technologies similar to those implemented on the Smart Grid Investment Grant (SGIG) projects. Four technical reports cover the various types of technologies deployed in the SGIG projects, distribution automation, demand response, energy storage, and renewables integration. A fifth report in the series examines the benefits of deploying these technologies on a national level. This technical report examines the impacts of addition of renewable resources- solar and wind in the distribution system as deployed in the SGIG projects.

  8. Worldwide telemedicine services based on distributed multimedia electronic patient records by using the second generation Web server hyperwave.

    PubMed Central

    Quade, G.; Novotny, J.; Burde, B.; May, F.; Beck, L. E.; Goldschmidt, A.

    1999-01-01

    A distributed multimedia electronic patient record (EPR) is a central component of a medicine-telematics application that supports physicians working in rural areas of South America, and offers medical services to scientists in Antarctica. A Hyperwave server is used to maintain the patient record. As opposed to common web servers--and as a second generation web server--Hyperwave provides the capability of holding documents in a distributed web space without the problem of broken links. This enables physicians to browse through a patient's record by using a standard browser even if the patient's record is distributed over several servers. The patient record is basically implemented on the "Good European Health Record" (GEHR) architecture. Images Figure 1 PMID:10566494

  9. What interactions can distort the orientational distribution of interfacial water molecules as probed by second harmonic and sum frequency generation?

    PubMed

    de Beer, Alex G F; Roke, Sylvie

    2016-07-28

    Aqueous interfaces are omnipresent in nature. Nonlinear optical methods such as second harmonic and sum frequency generation (SHG/SFG) are valuable techniques to access molecular level information from these interfaces. In the interpretation of SHG and SFG data for both scattering and reflection mode experiments, the relation between the second-order hyperpolarizability tensor β(2), a molecular property, and the surface second-order susceptibility χ(2), a surface averaged property, plays a central role. To correctly describe the molecular details of the interface, it needs to be determined how molecules are oriented, and what the influence is of interfacial electrostatic fields and H-bonding on the orientational distribution. Here, we revisit the relations between β(2) and χ(2) and show, by means of a Boltzmann average, that significant energy differences are needed to generate measurable changes in the molecular orientational distribution at the interface. In practice, H-bonding and surface pressure such as applied in a Langmuir trough can be strong enough to alter the shape of the orientational distribution function of water. In contrast, electrostatic fields, such as those present in the Stern layer, will not have a significant impact on the shape of the orientational distribution function of water molecules.

  10. Parallel aligned liquid crystal on silicon display based optical set-up for the generation of polarization spatial distributions

    NASA Astrophysics Data System (ADS)

    Estévez, Irene; Lizana, Angel; Zheng, Xuejie; Peinado, Alba; Ramírez, Claudio; Martínez, Jose Luis; Márquez, Andrés.; Moreno, Ignacio; Campos, Juan

    2015-06-01

    Liquid Crystals on Silicon (LCOS) displays are a type of LCDs that work in reflection. Such devices, due to the double pass that the light beam performs through the LC cells, lead to larger phase modulation than transmissive LCDs with the same thickness. By taking advantage of this modulation capability exhibited by LCOS displays, we propose a new experimental set-up which is able to provide customized state of polarization spatial distributions just by means of a single LCOS display. To this aim, a double reflection on different halves of the display is properly performed. This fact is achieved by including a compact optical system that steers the light and performs a proper polarization plane rotation. The set-up has been experimentally implemented and some experimental concerns are discussed. The suitability of the system is provided by generating different experimental spatial distributions of polarization. In this regard, well-known polarization distributions, as axial, azimuthal or spiral linear polarization patterns are here provided. Based on the excellent results obtained, the suitability of the system to generate different spatially variant distributions of polarization is validated.

  11. Distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings.

    PubMed

    Tian, Jiajun; Zhang, Qi; Han, Ming

    2013-03-11

    Active ultrasonic testing is widely used for medical diagnosis, material characterization and structural health monitoring. Ultrasonic transducer is a key component in active ultrasonic testing. Due to their many advantages such as small size, light weight, and immunity to electromagnetic interference, fiber-optic ultrasonic transducers are particularly attractive for permanent, embedded applications in active ultrasonic testing for structural health monitoring. However, current fiber-optic transducers only allow effective ultrasound generation at a single location of the fiber end. Here we demonstrate a fiber-optic device that can effectively generate ultrasound at multiple, selected locations along a fiber in a controllable manner based on a smart light tapping scheme that only taps out the light of a particular wavelength for laser-ultrasound generation and allow light of longer wavelengths pass by without loss. Such a scheme may also find applications in remote fiber-optic device tuning and quasi-distributed biochemical fiber-optic sensing.

  12. IEEE 1547 National Standard for Interconnecting Distributed Generation: How Could It Help My Facility? Preprint

    SciTech Connect

    Basso, T.; Friedman, N. R.

    2003-11-01

    This article summarizes the purpose, development, and impact of the Institute of Electrical and Electronics Engineers 1547 Standard for Interconnecting Distributed Resources With Electric Power Systems. Also included is a short explanation of supporting standards IEEE P1547.1, P1547.2, and P1547.3.

  13. Development of a wide band radiative transfer model based on a fast correlated k-distributions generation

    NASA Astrophysics Data System (ADS)

    Croize, Laurence; Pierro, Jean; Huet, Thierry; Labarre, Luc

    2016-04-01

    MATISSE which acronym means Advanced Modeling of the Earth for Environment and Scenes Simulation is developed by ONERA since the mid 1990's. The code main functionality is to compute spectral or integrated natural background radiance images. Natural backgrounds include the atmosphere, low and high altitude clouds, sea and land. It can also provide specific radiative atmospheric terms as path transmission, path radiances, sky radiances or local illumination around a target point. Spectral bandwidth ranges from 700 to 25000 cm-1 wavenumber (i.e. from 0.4 to 14 μm). As far as molecular absorption is concerned, MATISSE v2.0 is based on a correlated K (CK) model and needs a pre-generation of the k-distributions. This method is very precise but is time consuming and is done as an offline calculation. In answer to the increasing need of rapid radiative transfer codes, the future version of the MATISSE v3.0 will include a fast radiative transfer model at low and at medium spectral resolution. This work aims to develop a fast wide band CK model for the acceleration of radiative transfer calculation. As a first step, a statistical k-distributions fast generator was developed. It allows generating k-distributions from 700 to 25000 cm-1 with a spectral resolution of 1 cm-1 in less than 30 ms(*) for one altitude (that means about three orders of magnitude faster than before). Such speed allows generating k-distributions online. To validate the model, we have compared the obtained transmission spectra with reference spectra using a mix of 6 molecules (H2O, CO2, O3, N2O, CO, CH4) in homogenous atmosphere corresponding to different altitudes from 0 to 105 km. Reference spectra were calculated as the convolution of a spectrum obtained with a line by line model and a gate function of 1 cm-1 wide. An average difference of 3×10-3 % and a standard deviation of 3.3% were typically obtained. As a second step, this method of rapid k-distributions generation is now being coupled with a

  14. Cost Analysis of Electric Grid Enhancement Utilizing Distributed Generation in Post-War Reconstruction

    DTIC Science & Technology

    2009-03-01

    IEEE Spectrum Online Article, "Re-engineering Iraq,” Feb. 2006.)....................................................................5 Figure 5...Capstone Microturbines (Source: Capstone Turbine Coorperation) ..............12 Figure 6: Caterpillar Model 3406C 300kW Reciprocating Diesel...Generator (Source: Caterpillar ) .......................................................................................................13 Figure 7

  15. Solid-State Power Generating Microdevices for Distributed Space System Architectures

    NASA Astrophysics Data System (ADS)

    Fleurial, J.-P.; Patel, J.; Snyder, G. J.; Huang, C.-K.; Averback, R.; Hill, C.; Chen, G.

    2001-01-01

    Deep space missions have a strong need for compact, high power density, reliable and long life electrical power generation and storage under extreme temperature conditions. Conventional power generating devices become inefficient at very low temperatures (temperatures lower than 200 K encountered during Mars missions for example) and rechargeable energy storage devices cannot be operated thereby limiting mission duration. At elevated temperatures (for example for planned solar probe or Venus lander missions), thin film interdiffusion destroys electronic devices used for generating and storing power. Solar power generation strongly depends upon the light intensity, which falls rapidly in deep interplanetary missions (beyond 5 AU), and in planetary missions in the sun shadow or in dusty environments (Mars, for example). Radioisotope thermoelectric generators (RTGs) have been successfully used for a number of deep space missions RTGs. However, their energy conversion efficiency and specific power characteristics are quite low, and this technology has been limited to relatively large systems (more than 100 W). The National Aeronautics and Space Administration (NASA) and the Jet Propulsion Laboratory (JPL) have been planning the use of much smaller spacecrafts that will incorporate a variety of microdevices and miniature vehicles such as microdetectors, microsensors, and microrovers. Except for electrochemical batteries and solar cells, there are currently no available miniaturized power sources. Novel technologies that will function reliably over a long duration mission (ten years and over), in harsh environments (temperature, pressure, and atmosphere) must be developed to enable the success of future space missions. It is also expected that such micropower sources could have a wide range of terrestrial applications, in particular when the limited lifetime and environmental limitations of batteries are key factors. Additional information is contained in the original

  16. Unnatural landscapes in ecology: Generating the spatial distribution of brine spills

    SciTech Connect

    Jager, Yetta; Efroymson, Rebecca Ann; Sublette, K.; Ashwood, Tom L

    2005-01-01

    Quantitative tools are needed to evaluate the ecological effects of increasing petroleum production. In this article, we describe two stochastic models for simulating the spatial distribution of brine spills on a landscape. One model uses general assumptions about the spatial arrangement of spills and their sizes; the second model distributes spills by siting rectangular well complexes and conditioning spill probabilities on the configuration of pipes. We present maps of landscapes with spills produced by the two methods and compare the ability of the models to reproduce a specified spill area. A strength of the models presented here is their ability to extrapolate from the existing landscape to simulate landscapes with a higher (or lower) density of oil wells.

  17. Advanced Inverter Technology for High Penetration Levels of PV Generation in Distribution Systems

    SciTech Connect

    Schauder, C.

    2014-03-01

    This subcontract report was completed under the auspices of the NREL/SCE High-Penetration Photovoltaic (PV) Integration Project, which is co-funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and the California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) program funded by the California Public Utility Commission (CPUC) and managed by Itron. This project is focused on modeling, quantifying, and mitigating the impacts of large utility-scale PV systems (generally 1-5 MW in size) that are interconnected to the distribution system. This report discusses the concerns utilities have when interconnecting large PV systems that interconnect using PV inverters (a specific application of frequency converters). Additionally, a number of capabilities of PV inverters are described that could be implemented to mitigate the distribution system-level impacts of high-penetration PV integration. Finally, the main issues that need to be addressed to ease the interconnection of large PV systems to the distribution system are presented.

  18. Distributed fiber optic sensor employing phase generate carrier for disturbance detection and location

    NASA Astrophysics Data System (ADS)

    Xu, Haiyan; Wu, Hongyan; Zhang, Xuewu; Zhang, Zhuo; Li, Min

    2015-05-01

    Distributed optic fiber sensor is a new type of system, which could be used in the long-distance and strong-EMI condition for monitoring and inspection. A method of external modulation with a phase modulator is proposed in this paper to improve the positioning accuracy of the disturbance in a distributed optic-fiber sensor. We construct distributed disturbance detecting system based on Michelson interferometer, and a phase modulator has been attached to the fiber sensor in front of the Faraday rotation mirror (FRM), to elevate the signal produced by interfering of the two lights reflected by the Faraday rotation Mirror to a high frequency, while other signals remain in the low frequency. Through a high pass filter and phase retrieve circus, a signal which is proportional to the external disturbance is acquired. The accuracy of disturbance positioning with this signal can be largely improved. The method is quite simple and easy to achieve. Theoretical analysis and experimental results show that, this method can effectively improve the positioning accuracy.

  19. Updated greenhouse gas and criteria air pollutant emission factors and their probability distribution functions for electricity generating units

    SciTech Connect

    Cai, H.; Wang, M.; Elgowainy, A.; Han, J.

    2012-07-06

    Greenhouse gas (CO{sub 2}, CH{sub 4} and N{sub 2}O, hereinafter GHG) and criteria air pollutant (CO, NO{sub x}, VOC, PM{sub 10}, PM{sub 2.5} and SO{sub x}, hereinafter CAP) emission factors for various types of power plants burning various fuels with different technologies are important upstream parameters for estimating life-cycle emissions associated with alternative vehicle/fuel systems in the transportation sector, especially electric vehicles. The emission factors are typically expressed in grams of GHG or CAP per kWh of electricity generated by a specific power generation technology. This document describes our approach for updating and expanding GHG and CAP emission factors in the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model developed at Argonne National Laboratory (see Wang 1999 and the GREET website at http://greet.es.anl.gov/main) for various power generation technologies. These GHG and CAP emissions are used to estimate the impact of electricity use by stationary and transportation applications on their fuel-cycle emissions. The electricity generation mixes and the fuel shares attributable to various combustion technologies at the national, regional and state levels are also updated in this document. The energy conversion efficiencies of electric generating units (EGUs) by fuel type and combustion technology are calculated on the basis of the lower heating values of each fuel, to be consistent with the basis used in GREET for transportation fuels. On the basis of the updated GHG and CAP emission factors and energy efficiencies of EGUs, the probability distribution functions (PDFs), which are functions that describe the relative likelihood for the emission factors and energy efficiencies as random variables to take on a given value by the integral of their own probability distributions, are updated using best-fit statistical curves to characterize the uncertainties associated with GHG and CAP emissions in life

  20. A Study on Grid-Square Statistics Based Estimation of Regional Electricity Demand and Regional Potential Capacity of Distributed Generators

    NASA Astrophysics Data System (ADS)

    Kato, Takeyoshi; Sugimoto, Hiroyuki; Suzuoki, Yasuo

    We established a procedure for estimating regional electricity demand and regional potential capacity of distributed generators (DGs) by using a grid square statistics data set. A photovoltaic power system (PV system) for residential use and a co-generation system (CGS) for both residential and commercial use were taken into account. As an example, the result regarding Aichi prefecture was presented in this paper. The statistical data of the number of households by family-type and the number of employees by business category for about 4000 grid-square with 1km × 1km area was used to estimate the floor space or the electricity demand distribution. The rooftop area available for installing PV systems was also estimated with the grid-square statistics data set. Considering the relation between a capacity of existing CGS and a scale-index of building where CGS is installed, the potential capacity of CGS was estimated for three business categories, i.e. hotel, hospital, store. In some regions, the potential capacity of PV systems was estimated to be about 10,000kW/km2, which corresponds to the density of the existing area with intensive installation of PV systems. Finally, we discussed the ratio of regional potential capacity of DGs to regional maximum electricity demand for deducing the appropriate capacity of DGs in the model of future electricity distribution system.

  1. Independent Orbiter Assessment (IOA): Analysis of the electrical power distribution and control/electrical power generation subsystem

    NASA Technical Reports Server (NTRS)

    Patton, Jeff A.

    1986-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. This report documents the independent analysis results corresponding to the Orbiter Electrical Power Distribution and Control (EPD and C)/Electrical Power Generation (EPG) hardware. The EPD and C/EPG hardware is required for performing critical functions of cryogenic reactant storage, electrical power generation and product water distribution in the Orbiter. Specifically, the EPD and C/EPG hardware consists of the following components: Power Section Assembly (PSA); Reactant Control Subsystem (RCS); Thermal Control Subsystem (TCS); Water Removal Subsystem (WRS); and Power Reactant Storage and Distribution System (PRSDS). The IOA analysis process utilized available EPD and C/EPG hardware drawings and schematics for defining hardware assemblies, components, and hardware items. Each level of hardware was evaluated and analyzed for possible failure modes and effects. Criticality was assigned based upon the severity of the effect for each failure mode.

  2. Carrier Step-by-Step Transport Initiated by Precise Defect Distribution Engineering for Efficient Photocatalytic Hydrogen Generation.

    PubMed

    Chen, Jiewei; Wu, Gaoxiang; Wang, Tianyue; Li, Xiaodan; Li, Meicheng; Sang, Yuanhua; Liu, Hong

    2017-02-08

    Semiconductor photocatalysts have been widely used for solar-to-hydrogen conversion; however, efficient photocatalytic hydrogen generation still remains a challenge. To improve the photocatalytic activity, the critical step is the transport of photogenerated carriers from bulk to surface. Here, we report the carrier step-by-step transport (CST) for semiconductor photocatalysts through precise defect engineering. In CST, carriers can fast transport from bulk to shallow traps in the defective subsurface first, and then transfer to the surface active acceptors. The key challenge of initiating CST lies in fine controlling defect distribution in semiconductor photocatalysts to introduce the special band matching between the crystalline bulk and defect-controllable surface, moderate bridgelike shallow traps induced by subsurface defects, and abundant surface active sites induced by surface defects. In our proof-of-concept demonstration, the CST was introduced into typical semiconductor TiO2 assisted by the fluorine-assisted kinetic hydrolysis method, and the designed TiO2 can exhibit the state-of-the-art photocatalytic hydrogen generation rate among anatase TiO2 up to 13.21 mmol h(-1) g(-1), which is 120 times enhanced compared with crystalline anatase TiO2 under sunlight. The CST initiated by precise defect distribution engineering provides a new sight on greatly improving photocatalytic hydrogen generation performance of semiconductor catalysts.

  3. Space and energy. [space systems for energy generation, distribution and control

    NASA Technical Reports Server (NTRS)

    Bekey, I.

    1976-01-01

    Potential contributions of space to energy-related activities are discussed. Advanced concepts presented include worldwide energy distribution to substation-sized users using low-altitude space reflectors; powering large numbers of large aircraft worldwide using laser beams reflected from space mirror complexes; providing night illumination via sunlight-reflecting space mirrors; fine-scale power programming and monitoring in transmission networks by monitoring millions of network points from space; prevention of undetected hijacking of nuclear reactor fuels by space tracking of signals from tagging transmitters on all such materials; and disposal of nuclear power plant radioactive wastes in space.

  4. Distribution Coefficients (Kd Values) for Waste Resins Generated from the K and L Disassembly Basin Facilities

    SciTech Connect

    Kaplan, D.I.

    2002-12-02

    The objective of this study was to measure 14C, 129I, and 99Tc Kd values of spent resin generated from the K and L Disassembly Basin Facilities. The scope of the work was to conduct Kd measurements of resins combined in the ratio that they are disposed, 42:58 cation:anion. Because it was not known how these spent resins would be buried, it was necessary to measure the Kd values in such a manner as to simulate both trench and vault disposal. This was accomplished by using an acid-rain simulant (a standard U.S. Environmental Protection Agency protocol) and a cement leachate simulant .

  5. Counter Electrical Generation and Distribution: An Assessment for Global Strike in 2035

    DTIC Science & Technology

    2012-02-15

    Volumetric weapons carry the baggage of increased collateral damage and borderline Weapon of Mass Destruction/Weapon of Mass Disruption (WMD) (see Definition...add clarity if needed by the reader. Dis·rupt (d s-r pt ) tr.v. dis·rupt·ed, dis·rupt·ing, dis·rupts 1. To throw into confusion or disorder ...transmission lines, electrical stations and substations to power attachment point to end user domicile. Includes domicile alternative power generation

  6. Timing of seed dispersal generates a bimodal seed bank depth distribution

    USGS Publications Warehouse

    Espinar, J.L.; Thompson, K.; Garcia, L.V.

    2005-01-01

    The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down cracks and rapidly become deeply buried. We investigated this possibility for three dominant clonal perennials (Scirpus maritimus, S. litoralis, and Juncus subulatus) in the Don??ana salt marsh, a nontidal marsh with a Mediterranean climate located in southwest Spain. Two species, which shed most of their seed during the dry season and have seeds with low buoyancy, had bimodal viable seed depth distributions, with peak densities at the surface and at 16-20 cm. A third species, which shed most seeds after soil cracks had closed and had seeds with high buoyancy, had viable seeds only in surface soil. Bimodal seed bank depth distributions may be relatively common in seasonally dry habitats with fine-textured soils, but their ecological significance has not been investigated.

  7. Generation of murine induced pluripotent stem cells by using high-density distributed electrodes network.

    PubMed

    Lu, Ming-Yu; Li, Zhihong; Hwang, Shiaw-Min; Linju Yen, B; Lee, Gwo-Bin

    2015-09-01

    This study reports a robust method of gene transfection in a murine primary cell model by using a high-density electrodes network (HDEN). By demonstrating high cell viability after gene transfection and successful expression of transgenes including fluorescent proteins, the HDEN device shows great promise as a solution in which reprogramming efficiency using non-viral induction for generation of murine induced pluripotent stem cells (iPSCs) is optimized. High and steady transgene expression levels in host cells of iPSCs can be demonstrated using this method. Moreover, the HDEN device achieved successful gene transfection with a low voltage of less than 180 V while requiring relatively low cell numbers (less than 1.5 × 10(4) cells). The results are comparable to current conventional methods, demonstrating a reasonable fluorescent-plasmid transfection rate (42.4% in single transfection and 24.5% in triple transfection) and high cell viability of over 95%. The gene expression levels of each iPSC factor was measured to be over 10-fold higher than that reported in previous studies using a single mouse embryonic fibroblast cell. Our results demonstrate that the generation of iPSCs using HDEN transfection of plasmid DNA may be a feasible and safe alternative to using viral transfection methods in the near future.

  8. Generation and distribution of PAHs in the process of medical waste incineration.

    PubMed

    Chen, Ying; Zhao, Rongzhi; Xue, Jun; Li, Jinhui

    2013-05-01

    After the deadly earthquake on May 12, 2008 in Wenchuan county of China, several different incineration approaches were used for medical waste disposal. This paper investigates the generation properties of polycyclic aromatic hydrocarbons (PAHs) during the incineration. Samples were collected from the bottom ash in an open burning slash site, surface soil at the open burning site, bottom ash from a simple incinerator, bottom ash generated from the municipal solid waste (MSW) incinerator used for medical waste disposal, and bottom ash and fly ash from an incinerator exclusively used for medical waste. The species of PAHs were analyzed, and the toxicity equivalency quantities (TEQs) of samples calculated. Analysis results indicate that the content of total PAHs in fly ash was 1.8×10(3) times higher than that in bottom ash, and that the strongly carcinogenic PAHs with four or more rings accumulated sensitively in fly ash. The test results of samples gathered from open burning site demonstrate that Acenaphthylene (ACY), Acenaphthene (ACE), Fluorene (FLU), Phenanthrene (PHE), Anthracene (ANT) and other PAHs were inclined to migrate into surrounding environment along air and surface watershed corridors, while 4- to 6-ring PAHs accumulated more likely in soil. Being consistent with other studies, it has also been confirmed that increases in both free oxygen molecules and combustion temperatures could promote the decomposition of polycyclic PAHs. In addition, without the influence of combustion conditions, there is a positive correlation between total PCDD/Fs and total PAHs, although no such relationship has been found for TEQ.

  9. Smart grids: A paradigm shift on energy generation and distribution with the emergence of a new energy management business model

    NASA Astrophysics Data System (ADS)

    Cardenas, Jesus Alvaro

    An energy and environmental crisis will emerge throughout the world if we continue with our current practices of generation and distribution of electricity. A possible solution to this problem is based on the Smart grid concept, which is heavily influenced by Information and Communication Technology (ICT). Although the electricity industry is mostly regulated, there are global models used as roadmaps for Smart Grids' implementation focusing on technologies and the basic generation-distribution-transmission model. This project aims to further enhance a business model for a future global deployment. It takes into consideration the many factors interacting in this energy provision process, based on the diffusion of technologies and literature surveys on the available documents in the Internet as well as peer-reviewed publications. Tariffs and regulations, distributed energy generation, integration of service providers, consumers becoming producers, self-healing devices, and many other elements are shifting this industry into a major change towards liberalization and deregulation of this sector, which has been heavily protected by the government due to the importance of electricity for consumers. We propose an Energy Management Business Model composed by four basic elements: Supply Chain, Information and Communication Technology (ICT), Stakeholders Response, and the resulting Green Efficient Energy (GEE). We support the developed model based on the literature survey, we support it with the diffusion analysis of these elements, and support the overall model with two surveys: one for peers and professionals, and other for experts in the field, based on the Smart Grid Carnegie Melon Maturity Model (CMU SEI SGMM). The contribution of this model is a simple path to follow for entities that want to achieve environmental friendly energy with the involvement of technology and all stakeholders.

  10. Generation of Relativistic Electron Bunches with Arbitrary Current Distribution via Transverse-to-Longitudinal Phase Space Exchange

    SciTech Connect

    Piot, P.; Sun, Y.-E; Power, J.G.; Rihaoui, M.; /NICADD, DeKalb

    2010-07-01

    We propose a general method for tailoring the current distribution of relativistic electron bunches. The technique relies on a recently proposed method to exchange the longitudinal phase space emittance with one of the transverse emittances. The method consists of transversely shaping the bunch and then converting its transverse profile into a current profile via a transverse-to-longitudinal phase-space-exchange beamline. We show that it is possible to tailor the current profile to follow, in principle, any desired distributions. We demonstrate, via computer simulations, the application of the method to generate trains of microbunches with tunable spacing and linearly-ramped current profiles. We also briefly explore potential applications of the technique.

  11. Size distribution and concentration of soot generated in oil and gas-fired residential boilers under different combustion conditions

    NASA Astrophysics Data System (ADS)

    Jiménez, Santiago; Barroso, Jorge; Pina, Antonio; Ballester, Javier

    2016-05-01

    In spite of the relevance of residential heating burners in the global emission of soot particles to the atmosphere, relatively little information on their properties (concentration, size distribution) is available in the literature, and even less regarding the dependence of those properties on the operating conditions. Instead, the usual procedure to characterize those emissions is to measure the smoke opacity by several methods, among which the blackening of a paper after filtering a fixed amount of gas (Bacharach test) is predominant. In this work, the size distributions of the particles generated in the combustion of a variety of gaseous and liquid fuels in a laboratory facility equipped with commercial burners have been measured with a size classifier coupled to a particle counter in a broad range of operating conditions (air excesses), with simultaneous determination of the Bacharach index. The shape and evolution of the distribution with progressively smaller oxygen concentrations depends essentially on the state of the fuel: whereas the combustion of the gases results in monomodal distributions that 'shift' towards larger diameters, in the case of the gas-oils an ultrafine mode is always observed, and a secondary mode of coarse particle grows in relevance. In both cases, there is a strong, exponential correlation between the total mass concentration and the Bacharach opacity index, quite similar for both groups of fuels. The empirical expressions proposed may allow other researchers to at least estimate the emissions of numerous combustion facilities routinely characterized by their smoke opacities.

  12. A model for plant invasions: the role of distributed generation times.

    PubMed

    Méndez, Vicenç; Campos, Daniel; Sheppard, Andy W

    2009-10-01

    An analytical model consisting of adult plants and two types of seeds (unripe and mature) is considered and successfully tested using experimental data available for some invasive weeds (Echium plantagineum, Cytisus scoparius, Carduus nutans andCarduus acanthoides) from their native and exotic ranges. The model accounts for probability distribution functions (pdfs) for times of germination, growth, death and dispersal on two dimensions, so the general life-cycle of individuals is considered with high level of description. Our work provides for the first time, for a model containing all that life-cycle information, explicit relationship conditions for the invasive success and expressions for the speed of invasive fronts, which can be useful tools for invasions assessment. The expressions derived allow us to prove that the different phenotypes showed by the weeds in their native (exotic) ranges can explain their corresponding non-invasive (invasive) behavior.

  13. Blackboard system generator (BSG) - An alternative distributed problem-solving paradigm

    NASA Technical Reports Server (NTRS)

    Silverman, Barry G.; Feggos, Kostas; Chang, Joseph Shih

    1989-01-01

    A status review is presented for a generic blackboard-based distributed problem-solving environment in which multiple-agent cooperation can be effected. This environment is organized into a shared information panel, a chairman control panel, and a metaplanning panel. Each panel contains a number of embedded AI techniques that facilitate its operation and that provide heuristics for solving the underlying team-agent decision problem. The status of these panels and heuristics is described along with a number of robustness considerations. The techniques for each of the three panels and for four sets of paradigm-related advances are described, along with selected results from classroom teaching experiments and from three applications.

  14. Semiclassical Wigner distribution for a two-mode entangled state generated by an optical parametric oscillator

    SciTech Connect

    Dechoum, K.; Hahn, M. D.; Khoury, A. Z.

    2010-04-15

    We derive the steady-state solution of the Fokker-Planck equation that describes the dynamics of the nondegenerate optical parametric oscillator in the truncated Wigner representation of the density operator. We assume that the pump mode is strongly damped, which permits its adiabatic elimination. When the elimination is correctly executed, the resulting stochastic equations contain multiplicative noise terms and do not admit a potential solution. However, we develop a heuristic scheme leading to a satisfactory steady-state solution. This provides a clear view of the intracavity two-mode entangled state valid in all operating regimes of the optical parametric oscillator. A non-Gaussian distribution is obtained for the above threshold solution.

  15. Mutualistic Benefits Generate an Unequal Distribution of Risky Activities Among Unrelated Group Members

    NASA Astrophysics Data System (ADS)

    Kukuk, Penelope F.; Ward, Seamus A.; Jozwiak, Amy

    Recent studies provide a new challenge to the adequacy of theories concerning the evolution of cooperation among nonrelatives: some individuals perform high-risk activities while others do not. We examined a communal hymenopteran species, Lasioglossum(Chilalictus)hemichalceum, to determine why group members engaged in demonstrably risky activities (foraging) tolerate the selfish behavior (remaining in the nest) of unrelated nestmates. Experimental removal of adult females indicated that their presence is required for the protection of brood from ant predators. Nonforagers ensure the continued presence of adults in the nest if the risk-taking foragers die, thereby safeguarding the survival of forager offspring. This results in an unequal distribution of risky activities within social groups in which avoidance of risky activities by some group members is ultimately beneficial to risk takers.

  16. Research on renewable energy power generation complementarity and storage distribution model

    NASA Astrophysics Data System (ADS)

    Wei, Xiaoxia; Zhang, Jinfang

    2017-01-01

    This paper mainly studied the equivalent conversion relationships and model of different “quality “energies in process of multi-energy conversion. In energy interconnection system containing wind turbine, photovoltaic cell and energy storage systems, it gives renewable energy and storage distribution development model, considering comprehensive effect of load demand characteristics on energy utilization mode, multi-objective optimization model is established with objectives of both maximized energy utilization ratio and minimized system operation costs. Then, take Chinese one certain area as scenario, and give out “renewable energy utilization“, “energy transfer” and “total operating cost” three different analyses, according to the connection model. The result is compared with that for traditional energy utilization model. Feasibility of the proposed model is verified with simulation results.

  17. Generation of parallel transmission sub-pulses of spatial distribution based on polarizing splitting prism

    NASA Astrophysics Data System (ADS)

    Yang, Haifeng; Yang, Xiaoping; Sun, Xuna; Liu, Jun; Yang, Yong

    2016-09-01

    Parallel processing is the forefront of femtosecond laser micro-nano processing. The key to parallel processing is obtaining multichannel parallel femtosecond laser beams. A method of spatial parallel pulse splitting based on birefringence properties of polarizing splitting prism is proposed for obtaining multichannel parallel ultra-short pulse trains. The generated sub-pulses have the characteristics of equal energy and high similarity. More than that, the compact structure of the polarizing splitting prism makes it easier to be implemented. The accurate relationship between the space interval of pulse sequences and the structural angle, dimension and the distance between the two prisms is mathematically derived. The realizable array form of sub-pulse sequences is theoretically analyzed. The feasibility of the proposed method of femtosecond laser parallel processing is analyzed by software simulation and numerical calculation. The results will provide a new research direction for application of ultrashort pulse in parallel processing.

  18. Distribution and generation of the overpressure system, eastern Delaware Basin, western Texas and southern New Mexico

    SciTech Connect

    Luo, M.; Baker, M.R.; LeMone, D.V.

    1994-09-01

    Three subsurface pressure systems have been identified in the Delaware basin: an upper normal pressure system, a middle overpressure system, and a lower normal pressure system. The overpressure system occurs in the eastern Delaware basin, covering six Texas and New Mexico counties. The depth of the overpressure system ranges from 3100 to 5400 m. The normal fluid pressure gradient is 0.0103 MPa/m in the eastern Delaware basin. The highest overpressure gradient, however, approaches 0.02 MPa/m, which is close to the lithostatic gradient of 0.0231 MPa/m. An area of excess pressure occurs within the system where the highest excess pressure reaches 60 MPa. Local underpressured areas due to production are found in the lower normal pressure system in the War-Wink field area. Overpressure in the eastern Delaware basin is mainly associated with Mississippian, Pennsylvanian, and Permian (Wolfcampian) shale sequences, which also are major source rocks in the basin. Corrected bottom-hole temperature measurements indicate that the geothermal gradient within the overpressure zone is 25.1{degrees}C/km, which is higher than the basin`s average geothermal gradient of 21{degrees}C/km. Temperatures at the top and bottom of the overpressure system are about 80 and 115{degrees}C, respectively. The oil window in the War-Wink field is coincident with the overpressure system, which implies that hydrocarbon generation and migration are active in the overpressure system. A two-stage overpressure model is proposed. Hydrocarbon maturation combined with mechanical compaction disequilibrium and clay dehydration are the initial causes for overpressure generation due to an abnormal increase of fluid volume and pore space. Subsequently, the increase in temperature due to a decrease of thermal conductivity and fluid migration within the preexisting overpressure system would reinforce further overpressuring due to the fluid thermal expansion.

  19. The Cost-Optimal Distribution of Wind and Solar Generation Facilities in a Simplified Highly Renewable European Power System

    NASA Astrophysics Data System (ADS)

    Kies, Alexander; von Bremen, Lüder; Schyska, Bruno; Chattopadhyay, Kabitri; Lorenz, Elke; Heinemann, Detlev

    2016-04-01

    The transition of the European power system from fossil generation towards renewable sources is driven by different reasons like decarbonisation and sustainability. Renewable power sources like wind and solar have, due to their weather dependency, fluctuating feed-in profiles, which make their system integration a difficult task. To overcome this issue, several solutions have been investigated in the past like the optimal mix of wind and PV [1], the extension of the transmission grid or storages [2]. In this work, the optimal distribution of wind turbines and solar modules in Europe is investigated. For this purpose, feed-in data with an hourly temporal resolution and a spatial resolution of 7 km covering Europe for the renewable sources wind, photovoltaics and hydro was used. Together with historical load data and a transmission model , a simplified pan-European power power system was simulated. Under cost assumptions of [3] the levelized cost of electricity (LCOE) for this simplified system consisting of generation, consumption, transmission and backup units is calculated. With respect to the LCOE, the optimal distribution of generation facilities in Europe is derived. It is shown, that by optimal placement of renewable generation facilities the LCOE can be reduced by more than 10% compared to a meta study scenario [4] and a self-sufficient scenario (every country produces on average as much from renewable sources as it consumes). This is mainly caused by a shift of generation facilities towards highly suitable locations, reduced backup and increased transmission need. The results of the optimization will be shown and implications for the extension of renewable shares in the European power mix will be discussed. The work is part of the RESTORE 2050 project (Wuppertal Institute, Next Energy, University of Oldenburg), that is financed by the Federal Ministry of Education and Research (BMBF, Fkz. 03SFF0439A). [1] Kies, A. et al.: Kies, Alexander, et al

  20. NEXUS Scalable and Distributed Next-Generation Avionics Bus for Space Missions

    NASA Technical Reports Server (NTRS)

    He, Yutao; Shalom, Eddy; Chau, Savio N.; Some, Raphael R.; Bolotin, Gary S.

    2011-01-01

    A paper discusses NEXUS, a common, next-generation avionics interconnect that is transparently compatible with wired, fiber-optic, and RF physical layers; provides a flexible, scalable, packet switched topology; is fault-tolerant with sub-microsecond detection/recovery latency; has scalable bandwidth from 1 Kbps to 10 Gbps; has guaranteed real-time determinism with sub-microsecond latency/jitter; has built-in testability; features low power consumption (< 100 mW per Gbps); is lightweight with about a 5,000-logic-gate footprint; and is implemented in a small Bus Interface Unit (BIU) with reconfigurable back-end providing interface to legacy subsystems. NEXUS enhances a commercial interconnect standard, Serial RapidIO, to meet avionics interconnect requirements without breaking the standard. This unified interconnect technology can be used to meet performance, power, size, and reliability requirements of all ranges of equipment, sensors, and actuators at chip-to-chip, board-to-board, or box-to-box boundary. Early results from in-house modeling activity of Serial RapidIO using VisualSim indicate that the use of a switched, high-performance avionics network will provide a quantum leap in spacecraft onboard science and autonomy capability for science and exploration missions.

  1. Monochromatic x-ray generator utilizing angle dependence of bremsstrahlung x-ray distribution

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Ichimaru, Toshio; Takayama, Kazuyoshi; Ido, Hideaki

    2005-08-01

    This generator consists of the following components: a constant high-voltage power supply, a filament power supply, a turbomolecular pump, and an x-ray tube. The x-ray tube is a demountable diode which is connected to the turbomolecular pump and consists of the following major devices: a molybdenum rod target, a tungsten hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate x-ray window 0.25 mm in thickness, and a stainless-steel tube body. In the x-ray tube, the positive high voltage is applied to the anode (target) electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied was from 22 to 36 kV, and the tube current was regulated to within 100 μA by the filament temperature. The exposure time is controlled in order to obtain optimum x-ray intensity. The electron beams from the cathode are converged to the target by the focusing electrode, and clean Kα rays are produced through the focusing electrode using a 20-μm-thick zirconium filter. The x-ray intensity was 12.1 μGy/s at 1.0 m from the x-ray source with a tube voltage of 30 kV and a tube current of 100 μA, and monochromatic radiography was performed using a computed radiography system.

  2. Characteristic X-ray Generator Utilizing Angle Dependence of Bremsstrahlung X-ray Distribution

    NASA Astrophysics Data System (ADS)

    Sato, Eiichi; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Inoue, Takashi; Ogawa, Akira; Sato, Shigehiro; Takayama, Kazuyoshi; Onagawa, Jun

    2006-04-01

    This generator consists of the following components: a constant high-voltage power supply, a filament power supply, a turbomolecular pump, and an X-ray tube. The X-ray tube is a demountable diode which is connected to the turbomolecular pump and consists of the following major devices: a molybdenum rod target, a tungsten hairpin cathode (filament), a focusing (Wehnelt) electrode, a polyethylene terephthalate X-ray window 0.25 mm in thickness, and a stainless-steel tube body. In the X-ray tube, the positive high voltage is applied to the anode (target) electrode, and the cathode is connected to the tube body (ground potential). In this experiment, the tube voltage applied was from 22 to 36 kV, and the tube current was regulated to within 100 μA by the filament temperature. The exposure time is controlled in order to obtain optimum X-ray intensity. The electron beams from the cathode are converged to the target by the focusing electrode, and clean K-series characteristic X-rays are produced through the focusing electrode without using a filter. The X-ray intensity was 26.6 μGy/s at 1.0 m from the X-ray source with a tube voltage of 30 kV and a tube current of 100 μA, and quasi-monochromatic radiography was performed using a computed radiography system.

  3. Advanced Propulsion Power Distribution System for Next Generation Electric/Hybrid Vehicle. Phase 1; Preliminary System Studies

    NASA Technical Reports Server (NTRS)

    Bose, Bimal K.; Kim, Min-Huei

    1995-01-01

    The report essentially summarizes the work performed in order to satisfy the above project objective. In the beginning, different energy storage devices, such as battery, flywheel and ultra capacitor are reviewed and compared, establishing the superiority of the battery. Then, the possible power sources, such as IC engine, diesel engine, gas turbine and fuel cell are reviewed and compared, and the superiority of IC engine has been established. Different types of machines for drive motor/engine generator, such as induction machine, PM synchronous machine and switched reluctance machine are compared, and the induction machine is established as the superior candidate. Similar discussion was made for power converters and devices. The Insulated Gate Bipolar Transistor (IGBT) appears to be the most superior device although Mercury Cadmium Telluride (MCT) shows future promise. Different types of candidate distribution systems with the possible combinations of power and energy sources have been discussed and the most viable system consisting of battery, IC engine and induction machine has been identified. Then, HFAC system has been compared with the DC system establishing the superiority of the former. The detailed component sizing calculations of HFAC and DC systems reinforce the superiority of the former. A preliminary control strategy has been developed for the candidate HFAC system. Finally, modeling and simulation study have been made to validate the system performance. The study in the report demonstrates the superiority of HFAC distribution system for next generation electric/hybrid vehicle.

  4. Internuclear distance R-distribution of high-order harmonic generation from H2+ and its isotopes

    NASA Astrophysics Data System (ADS)

    Liu, Hang; Castle, Rich-Samuel; Feng, Liqiang

    2017-03-01

    Internuclear distance (R) distribution of high-order harmonic generation from H2+ and its isotopes have been theoretically investigated. We found that in the presence of the few-cycle pulse, the harmonics mainly produce from R = 2.0 a.u. to R = 4.5 a.u. and the odd harmonics can be found in the harmonic spectra. With the increase of the pulse duration, the harmonics can be generated from R = 2.0 a.u. to the larger internuclear distance (e.g. R = 15.0 a.u.) and the even/odd harmonics can be obtained in the below/above-threshold harmonic regions. Moreover, the intensities of the harmonics can be enhanced in the presence of the multi-cycle pulse, but the intensities of the below-threshold harmonics can be reduced with the increase of the nuclear mass (e.g. D or T). The time-dependent nuclear motions, the ionization probabilities, the time-frequency analyses of the harmonic spectra and the R-dependent time-dependent wave functions have been shown to explain the R-distribution of the harmonic spectra from H2+ and its isotopes.

  5. Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring

    PubMed Central

    Bazzo, João Paulo; Pipa, Daniel Rodrigues; da Silva, Erlon Vagner; Martelli, Cicero; Cardozo da Silva, Jean Carlos

    2016-01-01

    This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS) and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure. PMID:27618040

  6. Sparse Reconstruction for Temperature Distribution Using DTS Fiber Optic Sensors with Applications in Electrical Generator Stator Monitoring.

    PubMed

    Bazzo, João Paulo; Pipa, Daniel Rodrigues; da Silva, Erlon Vagner; Martelli, Cicero; Cardozo da Silva, Jean Carlos

    2016-09-07

    This paper presents an image reconstruction method to monitor the temperature distribution of electric generator stators. The main objective is to identify insulation failures that may arise as hotspots in the structure. The method is based on temperature readings of fiber optic distributed sensors (DTS) and a sparse reconstruction algorithm. Thermal images of the structure are formed by appropriately combining atoms of a dictionary of hotspots, which was constructed by finite element simulation with a multi-physical model. Due to difficulties for reproducing insulation faults in real stator structure, experimental tests were performed using a prototype similar to the real structure. The results demonstrate the ability of the proposed method to reconstruct images of hotspots with dimensions down to 15 cm, representing a resolution gain of up to six times when compared to the DTS spatial resolution. In addition, satisfactory results were also obtained to detect hotspots with only 5 cm. The application of the proposed algorithm for thermal imaging of generator stators can contribute to the identification of insulation faults in early stages, thereby avoiding catastrophic damage to the structure.

  7. DISTRIBUTION COEFICIENTS (KD) GENERATED FROM A CORE SAMPLE COLLECTED FROM THE SALTSTONE DISPOSAL FACILITY

    SciTech Connect

    Almond, P.; Kaplan, D.

    2011-04-25

    Core samples originating from Vault 4, Cell E of the Saltstone Disposal Facility (SDF) were collected in September of 2008 (Hansen and Crawford 2009, Smith 2008) and sent to SRNL to measure chemical and physical properties of the material including visual uniformity, mineralogy, microstructure, density, porosity, distribution coefficients (K{sub d}), and chemical composition. Some data from these experiments have been reported (Cozzi and Duncan 2010). In this study, leaching experiments were conducted with a single core sample under conditions that are representative of saltstone performance. In separate experiments, reducing and oxidizing environments were targeted to obtain solubility and Kd values from the measurable species identified in the solid and aqueous leachate. This study was designed to provide insight into how readily species immobilized in saltstone will leach from the saltstone under oxidizing conditions simulating the edge of a saltstone monolith and under reducing conditions, targeting conditions within the saltstone monolith. Core samples were taken from saltstone poured in December of 2007 giving a cure time of nine months in the cell and a total of thirty months before leaching experiments began in June 2010. The saltstone from Vault 4, Cell E is comprised of blast furnace slag, class F fly ash, portland cement, and Deliquification, Dissolution, and Adjustment (DDA) Batch 2 salt solution. The salt solution was previously analyzed from a sample of Tank 50 salt solution and characterized in the 4QCY07 Waste Acceptance Criteria (WAC) report (Zeigler and Bibler 2009). Subsequent to Tank 50 analysis, additional solution was added to the tank solution from the Effluent Treatment Project as well as from inleakage from Tank 50 pump bearings (Cozzi and Duncan 2010). Core samples were taken from three locations and at three depths at each location using a two-inch diameter concrete coring bit (1-1, 1-2, 1-3; 2-1, 2-2, 2-3; 3-1, 3-2, 3-3) (Hansen and

  8. The distribution of intraplate volcanism and controls on the generation of intraplate magmatism

    NASA Astrophysics Data System (ADS)

    Adam, J.; Rushmer, T. A.; Smith, I. E.

    2011-12-01

    magmatism (i.e. near-solidus melting of the mantle) are relatively easy to produce and don't require extreme thermal conditions and/or special source materials. Thus the relationship between intraplate volcanism and convergent plate boundaries can be attributed to the generation of broad and long lived thermal perturbations in the latter environment.

  9. Development and Testing of a 6-Cylinder HCCI Engine for Distributed Generation

    SciTech Connect

    Flowers, D L; Martinez-Frias, J; Espinosa-Loza, F; Killingsworth, N; Aceves, S M; Dibble, R; Kristic, M; Bining, A

    2005-07-12

    consistent combustion in the 6 cylinders. The engine will then be tested for 1000 hours to demonstrate durability. This paper presents intermediate progress towards development of an HCCI engine for stationary power generation and next steps towards achieving the project goals.

  10. Distribution of the Fittest Individuals and the Rate of Muller's Ratchet in a Model with Overlapping Generations

    PubMed Central

    Metzger, Jakob J.; Eule, Stephan

    2013-01-01

    Muller's ratchet is a paradigmatic model for the accumulation of deleterious mutations in a population of finite size. A click of the ratchet occurs when all individuals with the least number of deleterious mutations are lost irreversibly due to a stochastic fluctuation. In spite of the simplicity of the model, a quantitative understanding of the process remains an open challenge. In contrast to previous works, we here study a Moran model of the ratchet with overlapping generations. Employing an approximation which describes the fittest individuals as one class and the rest as a second class, we obtain closed analytical expressions of the ratchet rate in the rare clicking regime. As a click in this regime is caused by a rare, large fluctuation from a metastable state, we do not resort to a diffusion approximation but apply an approximation scheme which is especially well suited to describe extinction events from metastable states. This method also allows for a derivation of expressions for the quasi-stationary distribution of the fittest class. Additionally, we confirm numerically that the formulation with overlapping generations leads to the same results as the diffusion approximation and the corresponding Wright-Fisher model with non-overlapping generations. PMID:24244123

  11. Using chemical shifts to generate structural ensembles for intrinsically disordered proteins with converged distributions of secondary structure

    PubMed Central

    Ytreberg, F Marty; Borcherds, Wade; Wu, Hongwei; Daughdrill, Gary W

    2015-01-01

    A short segment of the disordered p53 transactivation domain (p53TAD) forms an amphipathic helix when bound to the E3 ubiquitin ligase, MDM2. In the unbound p53TAD, this short segment has transient helical secondary structure. Using a method that combines broad sampling of conformational space with re-weighting, it is shown that it is possible to generate multiple, independent structural ensembles that have highly similar secondary structure distributions for both p53TAD and a P27A mutant. Fractional amounts of transient helical secondary structure were found at the MDM2 binding site that are very similar to estimates based directly on experimental observations. Structures were identified in these ensembles containing segments that are highly similar to short p53 peptides bound to MDM2, even though the ensembles were re-weighted using unbound experimental data. Ensembles were generated using chemical shift data (alpha carbon only, or in combination with other chemical shifts) and cross-validated by predicting residual dipolar couplings. We think this ensemble generator could be used to predict the bound state structure of protein interaction sites in IDPs if there are detectable amounts of matching transient secondary structure in the unbound state.

  12. Distributions.

    ERIC Educational Resources Information Center

    Bowers, Wayne A.

    This monograph was written for the Conference of the New Instructional Materials in Physics, held at the University of Washington in summer, 1965. It is intended for students who have had an introductory college physics course. It seeks to provide an introduction to the idea of distributions in general, and to some aspects of the subject in…

  13. Space-based solar power generation using a distributed network of satellites and methods for efficient space power transmission

    NASA Astrophysics Data System (ADS)

    McLinko, Ryan M.; Sagar, Basant V.

    2009-12-01

    Space-based solar power (SSP) generation is being touted as a solution to our ever-increasing energy consumption and dependence on fossil fuels. Satellites in Earth's orbit can capture solar energy through photovoltaic cells and transmit that power to ground based stations. Solar cells in orbit are not hindered by weather, clouds, or night. The energy generated by this process is clean and pollution-free. Although the concept of space-based solar power was initially proposed nearly 40 years ago, the level of technology in photovoltaics, power transmission, materials, and efficient satellite design has finally reached a level of maturity that makes solar power from space a feasible prospect. Furthermore, new strategies in methods for solar energy acquisition and transmission can lead to simplifications in design, reductions in cost and reduced risk. This paper proposes using a distributed array of small satellites to collect power from the Sun, as compared to the more traditional SSP design that consists of one monolithic satellite. This concept mitigates some of SSP's most troublesome historic constraints, such as the requirement for heavy lift launch vehicles and the need for significant assembly in space. Instead, a larger number of smaller satellites designed to collect solar energy are launched independently. A high frequency beam will be used to aggregate collected power into a series of transmission antennas, which beam the energy to Earth's surface at a lower frequency. Due to the smaller power expectations of each satellite and the relatively short distance of travel from low earth orbit, such satellites can be designed with smaller arrays. The inter-satellite rectenna devices can also be smaller and lighter in weight. Our paper suggests how SSP satellites can be designed small enough to fit within ESPA standards and therefore use rideshare to achieve orbit. Alternatively, larger versions could be launched on Falcon 9s or on Falcon 1s with booster stages

  14. A novel approach for generating flat optical frequency comb based on externally injected gain-switching distributed feedback semiconductor laser

    NASA Astrophysics Data System (ADS)

    Zhu, Huatao; Wang, Rong; Pu, Tao; Xiang, Peng; Zheng, Jilin; Fang, Tao

    2017-02-01

    In this paper, a novel approach for generating flat optical frequency comb (OFC) based on externally injected gain-switched distributed feedback (DFB) semiconductor laser is proposed and experimentally demonstrated. In the proposed system, the flatness, the number of OFC spectral lines, and the spectral line to background noise ratio can be tuned to their optimized values by adjusting the current of the modulation signal, the injection ratio and the detuning frequency. Since the frequency of the modulation signal decides the frequency spacing of the output spectral lines, OFC spectral lines of different spacing can be achieved. In the experiment, 10 spectral lines with 1.5 dB power variation are demonstrated to verify the proposed approach. In addition, the expansion of the spectral line is investigated.

  15. Frequency spectrum of focused broadband pulses of electromagnetic radiation generated by polarization currents with superluminally rotating distribution patterns.

    PubMed

    Ardavan, Houshang; Ardavan, Arzhang; Singleton, John

    2003-11-01

    We investigate the spectral features of the emission from a superluminal polarization current whose distribution pattern rotates (with an angular frequency omega) and oscillates (with a frequency omega > omega differing from an integral multiple of omega) at the same time. This type of polarization current is found in recent practical machines designed to investigate superluminal emission. Although all of the processes involved are linear, we find that the broadband emission contains frequencies that are higher than omega by a factor of the order of (omega/omega)2. This generation of frequencies not required for the creation of the source stems from mathematically rigorous consequences of the familiar classical expression for the retarded potential. The results suggest practical applications for superluminal polarization currents as broadband radio-frequency and infrared sources.

  16. Storage dynamics in hydropedological units control hillslope connectivity, runoff generation, and the evolution of catchment transit time distributions

    PubMed Central

    Tetzlaff, D; Birkel, C; Dick, J; Geris, J; Soulsby, C

    2014-01-01

    We examined the storage dynamics and isotopic composition of soil water over 12 months in three hydropedological units in order to understand runoff generation in a montane catchment. The units form classic catena sequences from freely draining podzols on steep upper hillslopes through peaty gleys in shallower lower slopes to deeper peats in the riparian zone. The peaty gleys and peats remained saturated throughout the year, while the podzols showed distinct wetting and drying cycles. In this region, most precipitation events are <10 mm in magnitude, and storm runoff is mainly generated from the peats and peaty gleys, with runoff coefficients (RCs) typically <10%. In larger events the podzolic soils become strongly connected to the saturated areas, and RCs can exceed 40%. Isotopic variations in precipitation are significantly damped in the organic-rich soil surface horizons due to mixing with larger volumes of stored water. This damping is accentuated in the deeper soil profile and groundwater. Consequently, the isotopic composition of stream water is also damped, but the dynamics strongly reflect those of the near-surface waters in the riparian peats. “pre-event” water typically accounts for >80% of flow, even in large events, reflecting the displacement of water from the riparian soils that has been stored in the catchment for >2 years. These riparian areas are the key zone where different source waters mix. Our study is novel in showing that they act as “isostats,” not only regulating the isotopic composition of stream water, but also integrating the transit time distribution for the catchment. Key Points Hillslope connectivity is controlled by small storage changes in soil units Different catchment source waters mix in large riparian wetland storage Isotopes show riparian wetlands set the catchment transit time distribution PMID:25506098

  17. Spatial distribution of sonoluminescence and sonochemiluminescence generated by cavitation bubbles in 1.2 MHz focused ultrasound field.

    PubMed

    Cao, Hua; Wan, Mingxi; Qiao, Yangzi; Zhang, Shusheng; Li, Ruixue

    2012-03-01

    An intensified charge coupled device (ICCD) camera was used to observe the spatial distribution of sonoluminescence (SL) and sonochemiluminescence (SCL) generated by cavitation bubbles in a 1.2 MHz focused ultrasound (FU) field in order to investigate the mechanisms of acoustic cavitation under different sonication conditions for FU therapeutic applications. It was found that SL emissions were located in the post-focal region. When the intensity of SL and SCL increased as the power rose, the growth of SCL was much higher than that of SL. In the post-focal region, the SCL emissions moved along specific paths and formed branch-like streamers. At the beginning of the ultrasound irradiation, cavitation bubbles generated SCL in both the pre-focal and the post-focal region. When the electrical power or the sonication time increased, the SCL in the post-focal region increased and became higher than that in the pre-focal region. The intensity of SCL in the focal region is usually the weakest because of "oversaturation". The spatial distribution of SCL near a tissue boundary differed from that obtained in free fields. It organized into special structures under different acoustic amplitudes. When the electrical power was relatively low, the SCL emission was conical shape which suggested a standing wave formation at the tissue-fluid boundary. When the electrical power exceeded a certain threshold, only a bright spot could be captured in the focus. The cavitation bubbles which centralized in the focus concentrated energy and hindered the formation of standing waves. With rising electrical power at high levels, besides a bright spot in the focus, there were some irregular light spots in pre-focal region, which indicated some cavitation bubbles or small bubble clusters achieved the threshold of SCL and induced the reaction with the luminol solution.

  18. Myocardial Drug Distribution Generated from Local Epicardial Application: Potential Impact of Cardiac Capillary Perfusion in a Swine Model Using Epinephrine

    PubMed Central

    Maslov, Mikhail Y.; Edelman, Elazer R.; Pezone, Matthew J.; Wei, Abraham E.; Wakim, Matthew G.; Murray, Michael R.; Tsukada, Hisashi; Gerogiannis, Iraklis S.; Groothuis, Adam; Lovich, Mark A.

    2014-01-01

    Prior studies in small mammals have shown that local epicardial application of inotropic compounds drives myocardial contractility without systemic side effects. Myocardial capillary blood flow, however, may be more significant in larger species than in small animals. We hypothesized that bulk perfusion in capillary beds of the large mammalian heart enhances drug distribution after local release, but also clears more drug from the tissue target than in small animals. Epicardial (EC) drug releasing systems were used to apply epinephrine to the anterior surface of the left heart of swine in either point-sourced or distributed configurations. Following local application or intravenous (IV) infusion at the same dose rates, hemodynamic responses, epinephrine levels in the coronary sinus and systemic circulation, and drug deposition across the ventricular wall, around the circumference and down the axis, were measured. EC delivery via point-source release generated transmural epinephrine gradients directly beneath the site of application extending into the middle third of the myocardial thickness. Gradients in drug deposition were also observed down the length of the heart and around the circumference toward the lateral wall, but not the interventricular septum. These gradients extended further than might be predicted from simple diffusion. The circumferential distribution following local epinephrine delivery from a distributed source to the entire anterior wall drove drug toward the inferior wall, further than with point-source release, but again, not to the septum. This augmented drug distribution away from the release source, down the axis of the left ventricle, and selectively towards the left heart follows the direction of capillary perfusion away from the anterior descending and circumflex arteries, suggesting a role for the coronary circulation in determining local drug deposition and clearance. The dominant role of the coronary vasculature is further suggested by

  19. Optimal Battery Sizing in Photovoltaic Based Distributed Generation Using Enhanced Opposition-Based Firefly Algorithm for Voltage Rise Mitigation

    PubMed Central

    Wong, Ling Ai; Shareef, Hussain; Mohamed, Azah; Ibrahim, Ahmad Asrul

    2014-01-01

    This paper presents the application of enhanced opposition-based firefly algorithm in obtaining the optimal battery energy storage systems (BESS) sizing in photovoltaic generation integrated radial distribution network in order to mitigate the voltage rise problem. Initially, the performance of the original firefly algorithm is enhanced by utilizing the opposition-based learning and introducing inertia weight. After evaluating the performance of the enhanced opposition-based firefly algorithm (EOFA) with fifteen benchmark functions, it is then adopted to determine the optimal size for BESS. Two optimization processes are conducted where the first optimization aims to obtain the optimal battery output power on hourly basis and the second optimization aims to obtain the optimal BESS capacity by considering the state of charge constraint of BESS. The effectiveness of the proposed method is validated by applying the algorithm to the 69-bus distribution system and by comparing the performance of EOFA with conventional firefly algorithm and gravitational search algorithm. Results show that EOFA has the best performance comparatively in terms of mitigating the voltage rise problem. PMID:25054184

  20. Optimal battery sizing in photovoltaic based distributed generation using enhanced opposition-based firefly algorithm for voltage rise mitigation.

    PubMed

    Wong, Ling Ai; Shareef, Hussain; Mohamed, Azah; Ibrahim, Ahmad Asrul

    2014-01-01

    This paper presents the application of enhanced opposition-based firefly algorithm in obtaining the optimal battery energy storage systems (BESS) sizing in photovoltaic generation integrated radial distribution network in order to mitigate the voltage rise problem. Initially, the performance of the original firefly algorithm is enhanced by utilizing the opposition-based learning and introducing inertia weight. After evaluating the performance of the enhanced opposition-based firefly algorithm (EOFA) with fifteen benchmark functions, it is then adopted to determine the optimal size for BESS. Two optimization processes are conducted where the first optimization aims to obtain the optimal battery output power on hourly basis and the second optimization aims to obtain the optimal BESS capacity by considering the state of charge constraint of BESS. The effectiveness of the proposed method is validated by applying the algorithm to the 69-bus distribution system and by comparing the performance of EOFA with conventional firefly algorithm and gravitational search algorithm. Results show that EOFA has the best performance comparatively in terms of mitigating the voltage rise problem.

  1. Independent Orbiter Assessment (IOA): Analysis of the electrical power generation/power reactant storage and distribution subsystem

    NASA Technical Reports Server (NTRS)

    Gotch, S. M.

    1986-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA approach features a top-down analysis of the hardware to determine failure modes, criticality, and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NAA FMEA/CIL documentation. The independent analysis results corresponding to the Orbiter Electrical Power Generation (EPG)/Power Reactants Storage and Distribution (PRSD) System Hardware is documented. The EPG/PRSD hardware is required for performing critical functions of cryogenic hydrogen and oxygen storage and distribution to the Fuel Cell Powerplants (FCP) and Atmospheric Revitalization Pressure Control Subsystem (ARPCS). Specifically, the EPG/PRSD hardware consists of the following: Hydryogen (H2) tanks; Oxygen (O2) tanks; H2 Relief Valve/Filter Packages (HRVFP); O2 Relief Valve/Filter Packages (ORVFP); H2 Valve Modules (HVM); O2 Valve Modules (OVM); and O2 and H2 lines, components, and fittings.

  2. Free-space quantum key distribution with a high generation rate potassium titanyl phosphate waveguide photon-pair source

    NASA Astrophysics Data System (ADS)

    Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip R.; Floyd, Bertram; Lind, Alexander J.; Cavin, John D.; Helmick, Spencer R.

    2016-09-01

    A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The fully integrated photon-pair source consists of a 1064-nm pump diode laser, fiber-coupled to a dual element waveguide within which a pair of 1064-nm photons are up-converted to a single 532-nm photon in the first stage. In the second stage, the 532-nm photon is down-converted to an entangled photon-pair at 800 nm and 1600 nm which are fiber-coupled at the waveguide output. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. This is a significant step towards the long term goal of developing sources for high-rate Quantum Key Distribution (QKD) to enable Earth-space secure communications. Characterization and test results are presented. Details and preliminary results of a laboratory free space QKD experiment with the B92 protocol are also presented.

  3. Small-Signal Analysis of Autonomous Hybrid Distributed Generation Systems in Presence of Ultracapacitor and Tie-Line Operation

    NASA Astrophysics Data System (ADS)

    Ray, Prakash K.; Mohanty, Soumya R.; Kishor, Nand

    2010-07-01

    This paper presents small-signal analysis of isolated as well as interconnected autonomous hybrid distributed generation system for sudden variation in load demand, wind speed and solar radiation. The hybrid systems comprise of different renewable energy resources such as wind, photovoltaic (PV) fuel cell (FC) and diesel engine generator (DEG) along with the energy storage devices such as flywheel energy storage system (FESS) and battery energy storage system (BESS). Further ultracapacitors (UC) as an alternative energy storage element and interconnection of hybrid systems through tie-line is incorporated into the system for improved performance. A comparative assessment of deviation of frequency profile for different hybrid systems in the presence of different storage system combinations is carried out graphically as well as in terms of the performance index (PI), ie integral square error (ISE). Both qualitative and quantitative analysis reflects the improvements of the deviation in frequency profiles in the presence of the ultracapacitors (UC) as compared to other energy storage elements.

  4. Free-Space Quantum Key Distribution with a High Generation Rate Potassium Titanyl Phosphate Waveguide Photon-Pair Source

    NASA Technical Reports Server (NTRS)

    Wilson, Jeffrey D.; Chaffee, Dalton W.; Wilson, Nathaniel C.; Lekki, John D.; Tokars, Roger P.; Pouch, John J.; Roberts, Tony D.; Battle, Philip; Floyd, Bertram M.; Lind, Alexander J.; Cavin, John D.; Helmick, Spencer R.

    2016-01-01

    A high generation rate photon-pair source using a dual element periodically-poled potassium titanyl phosphate (PP KTP) waveguide is described. The fully integrated photon-pair source consists of a 1064-nanometer pump diode laser, fiber-coupled to a dual element waveguide within which a pair of 1064-nanometer photons are up-converted to a single 532-nanometer photon in the first stage. In the second stage, the 532-nanometer photon is down-converted to an entangled photon-pair at 800 nanometer and 1600 nanometer which are fiber-coupled at the waveguide output. The photon-pair source features a high pair generation rate, a compact power-efficient package, and continuous wave (CW) or pulsed operation. This is a significant step towards the long term goal of developing sources for high-rate Quantum Key Distribution (QKD) to enable Earth-space secure communications. Characterization and test results are presented. Details and preliminary results of a laboratory free-space QKD experiment with the B92 protocol are also presented.

  5. Dynamic wave field synthesis: enabling the generation of field distributions with a large space-bandwidth product.

    PubMed

    Kamau, Edwin N; Heine, Julian; Falldorf, Claas; Bergmann, Ralf B

    2015-11-02

    We present a novel approach for the design and fabrication of multiplexed computer generated volume holograms (CGVH) which allow for a dynamic synthesis of arbitrary wave field distributions. To achieve this goal, we developed a hybrid system that consists of a CGVH as a static element and an electronically addressed spatial light modulator as the dynamic element. We thereby derived a new model for describing the scattering process within the inhomogeneous dielectric material of the hologram. This model is based on the linearization of the scattering process within the Rytov approximation and incorporates physical constraints that account for voxel based laser-lithography using micro-fabrication of the holograms in a nonlinear optical material. In this article we demonstrate that this system basically facilitates a high angular Bragg selectivity on the order of 1°. Additionally, it allows for a qualitatively low cross-talk dynamic synthesis of predefined wave fields with a much larger space-bandwidth product (SBWP ≥ 8.7 × 10(6)) as compared to the current state of the art in computer generated holography.

  6. Independent Orbiter Assessment (IOA): Assessment of the electrical power generation/power reactant storage and distribution subsystem FMEA/CIL

    NASA Technical Reports Server (NTRS)

    Ames, B. E.

    1988-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) is presented. The IOA effort first completed an analysis of the Electrical Power Generation/Power Reactant Storage and Distribution (EPG/PRSD) subsystem hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL baselines with proposed Post 51-L updates included. A resolution of each discrepancy from the comparison is provided through additional analysis as required. The results of that comparison are documented for the Orbiter EPG/PRSD hardware. The comparison produced agreement on all but 27 FMEAs and 9 CIL items. The discrepancy between the number of IOA findings and NASA FMEAs can be partially explained by the different approaches used by IOA and NASA to group failure modes together to form one FMEA. Also, several IOA items represented inner tank components and ground operations failure modes which were not in the NASA baseline.

  7. Storage Dynamics and Non-Linear Connectivity between Landscape Units Control Runoff Generation and Stream Water Age Distributions

    NASA Astrophysics Data System (ADS)

    Soulsby, C.; Birkel, C.; Geris, J.; Tetzlaff, D.

    2015-12-01

    We assess the influence of storage dynamics and non-linearities in hydrological connectivity on runoff generation and stream water ages, using a long-term record of daily isotopes in precipitation and stream flow. These were used to test a parsimonious tracer-aided runoff model for a Scottish catchment. The model tracks tracers and the ages of water fluxes through and between conceptual stores representing steeper hillslopes, dynamically saturated riparian peatlands and deeper groundwater (i.e. the main landscape units involved in runoff generation). Storage is largest in groundwater and on the steep hillslopes, though most dynamic mixing occurs in smaller stores in the riparian peat. The model also couples the ecohydrological effects of different vegetation communities in contrasting landscape units, by estimating evaporation, resulting moisture deficits and the ages of evaporated waters, which also affect the generation and age of runoff. Both stream flow and isotope variations are well-captured by the model, and the simulated storage and tracer dynamics in the main landscape units are consistent with independent measurements. The model predicts the mean age of runoff as ~1.8 years. On a daily basis, this varies from ~1 month in storm events, when younger waters draining the riparian peatland dominate, to around 4 years in dry periods, when groundwater sustains flow. Hydrological connectivity between the units varies non-linearly with storage which depends upon antecedent conditions and event characteristics. This, in turn, determines the spatial distribution of flow paths and the integration of their contrasting non-stationary ages. Improving the representation of storage dynamics and quantifying the ages of water fluxes in such models gives a more complete conceptualisation of the importance of the soil water fluxes in critical zone processes and a framework for tracking diffuse pollutants in water quality assessment.

  8. Distribution of airway narrowing responses across generations and at branching points, assessed in vitro by anatomical optical coherence tomography

    PubMed Central

    2010-01-01

    Background Previous histological and imaging studies have shown the presence of variability in the degree of bronchoconstriction of airways sampled at different locations in the lung (i.e., heterogeneity). Heterogeneity can occur at different airway generations and at branching points in the bronchial tree. Whilst heterogeneity has been detected by previous experimental approaches, its spatial relationship either within or between airways is unknown. Methods In this study, distribution of airway narrowing responses across a portion of the porcine bronchial tree was determined in vitro. The portion comprised contiguous airways spanning bronchial generations (#3-11), including the associated side branches. We used a recent optical imaging technique, anatomical optical coherence tomography, to image the bronchial tree in three dimensions. Bronchoconstriction was produced by carbachol administered to either the adventitial or luminal surface of the airway. Luminal cross sectional area was measured before and at different time points after constriction to carbachol and airway narrowing calculated from the percent decrease in luminal cross sectional area. Results When administered to the adventitial surface, the degree of airway narrowing was progressively increased from proximal to distal generations (r = 0.80 to 0.98, P < 0.05 to 0.001). This 'serial heterogeneity' was also apparent when carbachol was administered via the lumen, though it was less pronounced. In contrast, airway narrowing was not different at side branches, and was uniform both in the parent and daughter airways. Conclusions Our findings demonstrate that the bronchial tree expresses intrinsic serial heterogeneity, such that narrowing increases from proximal to distal airways, a relationship that is influenced by the route of drug administration but not by structural variations accompanying branching sites. PMID:20092657

  9. Performance of dose calculation algorithms from three generations in lung SBRT: comparison with full Monte Carlo-based dose distributions.

    PubMed

    Ojala, Jarkko J; Kapanen, Mika K; Hyödynmaa, Simo J; Wigren, Tuija K; Pitkänen, Maunu A

    2014-03-06

    The accuracy of dose calculation is a key challenge in stereotactic body radiotherapy (SBRT) of the lung. We have benchmarked three photon beam dose calculation algorithms--pencil beam convolution (PBC), anisotropic analytical algorithm (AAA), and Acuros XB (AXB)--implemented in a commercial treatment planning system (TPS), Varian Eclipse. Dose distributions from full Monte Carlo (MC) simulations were regarded as a reference. In the first stage, for four patients with central lung tumors, treatment plans using 3D conformal radiotherapy (CRT) technique applying 6 MV photon beams were made using the AXB algorithm, with planning criteria according to the Nordic SBRT study group. The plans were recalculated (with same number of monitor units (MUs) and identical field settings) using BEAMnrc and DOSXYZnrc MC codes. The MC-calculated dose distributions were compared to corresponding AXB-calculated dose distributions to assess the accuracy of the AXB algorithm, to which then other TPS algorithms were compared. In the second stage, treatment plans were made for ten patients with 3D CRT technique using both the PBC algorithm and the AAA. The plans were recalculated (with same number of MUs and identical field settings) with the AXB algorithm, then compared to original plans. Throughout the study, the comparisons were made as a function of the size of the planning target volume (PTV), using various dose-volume histogram (DVH) and other parameters to quantitatively assess the plan quality. In the first stage also, 3D gamma analyses with threshold criteria 3%/3mm and 2%/2 mm were applied. The AXB-calculated dose distributions showed relatively high level of agreement in the light of 3D gamma analysis and DVH comparison against the full MC simulation, especially with large PTVs, but, with smaller PTVs, larger discrepancies were found. Gamma agreement index (GAI) values between 95.5% and 99.6% for all the plans with the threshold criteria 3%/3 mm were achieved, but 2%/2 mm

  10. Non-Maxwellian electron distribution functions due to self-generated turbulence in collisionless guide-field reconnection

    NASA Astrophysics Data System (ADS)

    Muñoz, P. A.; Büchner, J.

    2016-10-01

    Non-Maxwellian electron velocity space distribution functions (EVDFs) are useful signatures of plasma conditions and non-local consequences of collisionless magnetic reconnection. In the past, EVDFs were obtained mainly for antiparallel reconnection and under the influence of weak guide-fields in the direction perpendicular to the reconnection plane. EVDFs are, however, not well known, yet, for oblique (or component-) reconnection in case and in dependence on stronger guide-magnetic fields and for the exhaust (outflow) region of reconnection away from the diffusion region. In view of the multi-spacecraft Magnetospheric Multiscale Mission (MMS), we derived the non-Maxwellian EVDFs of collisionless magnetic reconnection in dependence on the guide-field strength bg from small ( b g ≈ 0 ) to very strong (bg = 8) guide-fields, taking into account the feedback of the self-generated turbulence. For this sake, we carried out 2.5D fully kinetic Particle-in-Cell simulations using the ACRONYM code. We obtained anisotropic EVDFs and electron beams propagating along the separatrices as well as in the exhaust region of reconnection. The beams are anisotropic with a higher temperature in the direction perpendicular rather than parallel to the local magnetic field. The beams propagate in the direction opposite to the background electrons and cause instabilities. We also obtained the guide-field dependence of the relative electron-beam drift speed, threshold, and properties of the resulting streaming instabilities including the strongly non-linear saturation of the self-generated plasma turbulence. This turbulence and its non-linear feedback cause non-adiabatic parallel electron acceleration. We further obtained the resulting EVDFs due to the non-linear feedback of the saturated self-generated turbulence near the separatrices and in the exhaust region of reconnection in dependence on the guide field strength. We found that the influence of the self-generated plasma turbulence

  11. Flow Distribution Control Characteristics in Marine Gas Turbine Waste- Heat Recovery Systems. Phase 2. Flow Distribution Control in Waste-Heat Steam Generators

    DTIC Science & Technology

    1982-07-01

    waste-heat steam generators. The applicable steam generator design concepts and general design consideration were reviewed and critical problems...a once-through forced-circulation steam generator design should be selected because of stability, reliability, compact- ness and lightweight...consists of three sections and one appendix. In Section I, the applicable steam generator design conccpts and general design * considerations are reviewed

  12. First detection of the adventive large rove beetle Ocypus nitens (Schrank) in Canada and an update of its Nearctic distribution using data generated by the public

    PubMed Central

    2016-01-01

    Abstract The adventive rove beetle Ocypus nitens (Staphylinidae: Staphylininae) is newly recorded in Canada (Ontario) and the state of Vermont, and additional range expansion is documented. The updated distribution of this large, conspicuous species is based mostly on data from digital photographs posted by users of the online community BugGuide. All available data are summarized and made available as a DarwinCore dataset, and an updated distribution map is provided. Citizen-generated distributional data continues to be a valuable ally in the detection of adventive insects and the study of their distributional dynamics. PMID:27956855

  13. Monte Carlo modelling of distributions of the d-d and d-t reaction products in a dedicated measuring chamber at the fast neutron generator

    NASA Astrophysics Data System (ADS)

    Wiącek, U.; Dankowski, J.

    2015-04-01

    A fast neutron generator with a tritium target can be used to generate d-d and d-t reaction products corresponding to thermonuclear reactions in tokamaks or stellarators. In this way, convenient laboratory conditions for tests of spectrometric detectors - prior to their installation at the big fusion devices - can be achieved. Distributions of the alpha particles, protons, deuterons, and tritons generated by the fast neutron generator operating at the Institute of Nuclear Physics PAN in Cracow, Poland, were calculated by means of the Monte Carlo (MC) codes. Results of this MC modelling are presented.

  14. NHash: Randomized N-Gram Hashing for Distributed Generation of Validatable Unique Study Identifiers in Multicenter Research

    PubMed Central

    Zhang, Guo-Qiang; Tao, Shiqiang; Xing, Guangming; Mozes, Jeno; Zonjy, Bilal; Lhatoo, Samden D

    2015-01-01

    Background A unique study identifier serves as a key for linking research data about a study subject without revealing protected health information in the identifier. While sufficient for single-site and limited-scale studies, the use of common unique study identifiers has several drawbacks for large multicenter studies, where thousands of research participants may be recruited from multiple sites. An important property of study identifiers is error tolerance (or validatable), in that inadvertent editing mistakes during their transmission and use will most likely result in invalid study identifiers. Objective This paper introduces a novel method called "Randomized N-gram Hashing (NHash)," for generating unique study identifiers in a distributed and validatable fashion, in multicenter research. NHash has a unique set of properties: (1) it is a pseudonym serving the purpose of linking research data about a study participant for research purposes; (2) it can be generated automatically in a completely distributed fashion with virtually no risk for identifier collision; (3) it incorporates a set of cryptographic hash functions based on N-grams, with a combination of additional encryption techniques such as a shift cipher; (d) it is validatable (error tolerant) in the sense that inadvertent edit errors will mostly result in invalid identifiers. Methods NHash consists of 2 phases. First, an intermediate string using randomized N-gram hashing is generated. This string consists of a collection of N-gram hashes f 1, f 2, ..., f k. The input for each function f i has 3 components: a random number r, an integer n, and input data m. The result, f i(r, n, m), is an n-gram of m with a starting position s, which is computed as (r mod |m|), where |m| represents the length of m. The output for Step 1 is the concatenation of the sequence f 1(r 1, n 1, m 1), f 2(r 2, n 2, m 2), ..., f k(r k, n k, m k). In the second phase, the intermediate string generated in Phase 1 is encrypted

  15. Cell uptake, intracellular distribution, fate and reactive oxygen species generation of polymer brush engineered CeO2-x NPs

    NASA Astrophysics Data System (ADS)

    Qiu, Yuan; Rojas, Elena; Murray, Richard A.; Irigoyen, Joseba; Gregurec, Danijela; Castro-Hartmann, Pablo; Fledderman, Jana; Estrela-Lopis, Irina; Donath, Edwin; Moya, Sergio E.

    2015-04-01

    Cerium Oxide nanoparticles (CeO2-x NPs) are modified with polymer brushes of negatively charged poly (3-sulfopropylmethacrylate) (PSPM) and positively charged poly (2-(methacryloyloxy)ethyl-trimethylammonium chloride) (PMETAC) by Atom Transfer Radical Polymerisation (ATRP). CeO2-x NPs are fluorescently labelled by covalently attaching Alexa Fluor® 488/Fluorescein isothiocyanate to the NP surface prior to polymerisation. Cell uptake, intracellular distribution and the impact on the generation of intracellular Reactive Oxygen Species (ROS) with respect to CeO2-x NPs are studied by means of Raman Confocal Microscopy (CRM), Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PSPM and PMETAC coated CeO2-x NPs show slower and less uptake compared to uncoated Brush modified NPs display a higher degree of co-localisation with cell endosomes and lysosomes after 24 h of incubation. They also show higher co-localisation with lipid bodies when compared to unmodified CeO2-x NPs. The brush coating does not prevent CeO2-x NPs from displaying antioxidant properties.Cerium Oxide nanoparticles (CeO2-x NPs) are modified with polymer brushes of negatively charged poly (3-sulfopropylmethacrylate) (PSPM) and positively charged poly (2-(methacryloyloxy)ethyl-trimethylammonium chloride) (PMETAC) by Atom Transfer Radical Polymerisation (ATRP). CeO2-x NPs are fluorescently labelled by covalently attaching Alexa Fluor® 488/Fluorescein isothiocyanate to the NP surface prior to polymerisation. Cell uptake, intracellular distribution and the impact on the generation of intracellular Reactive Oxygen Species (ROS) with respect to CeO2-x NPs are studied by means of Raman Confocal Microscopy (CRM), Transmission Electron Microscopy (TEM) and Inductively Coupled Plasma Mass Spectroscopy (ICP-MS). PSPM and PMETAC coated CeO2-x NPs show slower and less uptake compared to uncoated Brush modified NPs display a higher degree of co-localisation with cell

  16. Distributed video generation on a GPU-cluster for the web-based analysis of medical image data

    NASA Astrophysics Data System (ADS)

    Rößler, Friedemann A.; Wolff, Torsten; Iserhardt-Bauer, Sabine; Tomandl, Bernd; Hastreiter, Peter; Ertl, Thomas

    2007-03-01

    Modern 3D visualization environments for medical image data provide high interactivity and flexibility but depend on the expert knowledge and the experience of the user with respect to the software application. The definition of the visualization parameters is a manual time-consuming process and as a result, inter-patient or inter-study comparisons are extremely difficult. To overcome these drawbacks in case of the analysis and diagnosis of pathologies, standardization of 3D visualization is an important issue. For this purpose automatically generated digital video sequences can be used to convey the most important information contained in the data. In this paper, we present an improvement of our existing web-based service which is now able to calculate the video sequences in much shorter time exploiting the power of a GPU-cluster. The system requires to transfer a medical volume dataset from an arbitrary computer connected via Internet and sends back a number of video files automatically generated with direct volume rendering. To achieve an optimal load balancing of the available resources, the tasks of automatic adjustment of transfer functions, volume rendering, and video encoding are divided into small sub-requests, which are distributed to the different cluster nodes in order to be performed in parallel. An additional preview mode, which renders a number of dedicated frames, provides a direct feedback and quick overview. For the evaluation, we were focusing on the analysis of intracranial aneurysms and were able to show that the system can be successfully applied. Further on, the system was developed in a way that allows easy integration of other analysis tasks.

  17. The next generation Virgo cluster survey. VIII. The spatial distribution of globular clusters in the Virgo cluster

    SciTech Connect

    Durrell, Patrick R.; Accetta, Katharine; Côté, Patrick; Blakeslee, John P.; Ferrarese, Laura; McConnachie, Alan; Gwyn, Stephen; Peng, Eric W.; Zhang, Hongxin; Mihos, J. Christopher; Puzia, Thomas H.; Jordán, Andrés; Lançon, Ariane; Liu, Chengze; Cuillandre, Jean-Charles; Boissier, Samuel; Boselli, Alessandro; Courteau, Stéphane; Duc, Pierre-Alain; and others

    2014-10-20

    We report on a large-scale study of the distribution of globular clusters (GCs) throughout the Virgo cluster, based on photometry from the Next Generation Virgo Cluster Survey (NGVS), a large imaging survey covering Virgo's primary subclusters (Virgo A = M87 and Virgo B = M49) out to their virial radii. Using the g{sub o}{sup ′}, (g' – i') {sub o} color-magnitude diagram of unresolved and marginally resolved sources within the NGVS, we have constructed two-dimensional maps of the (irregular) GC distribution over 100 deg{sup 2} to a depth of g{sub o}{sup ′} = 24. We present the clearest evidence to date showing the difference in concentration between red and blue GCs over the full extent of the cluster, where the red (more metal-rich) GCs are largely located around the massive early-type galaxies in Virgo, while the blue (metal-poor) GCs have a much more extended spatial distribution with significant populations still present beyond 83' (∼215 kpc) along the major axes of both M49 and M87. A comparison of our GC maps to the diffuse light in the outermost regions of M49 and M87 show remarkable agreement in the shape, ellipticity, and boxiness of both luminous systems. We also find evidence for spatial enhancements of GCs surrounding M87 that may be indicative of recent interactions or an ongoing merger history. We compare the GC map to that of the locations of Virgo galaxies and the X-ray intracluster gas, and find generally good agreement between these various baryonic structures. We calculate the Virgo cluster contains a total population of N {sub GC} = 67, 300 ± 14, 400, of which 35% are located in M87 and M49 alone. For the first time, we compute a cluster-wide specific frequency S {sub N,} {sub CL} = 2.8 ± 0.7, after correcting for Virgo's diffuse light. We also find a GC-to-baryonic mass fraction ε {sub b} = 5.7 ± 1.1 × 10{sup –4} and a GC-to-total cluster mass formation efficiency ε {sub t} = 2.9 ± 0.5 × 10{sup –5}, the latter values

  18. Thermal electron acceleration by electric field spikes in the outer radiation belt: generation of field-aligned pitch angle distributions

    NASA Astrophysics Data System (ADS)

    Vasko, I.; Agapitov, O. V.; Mozer, F.; Artemyev, A.

    2015-12-01

    Van Allen Probes observations in the outer radiation belt have demonstrated an abundance non-linear electrostatic stucture called Time Domain Structures (TDS). One of the type of TDS is electrostatic electron-acoustic double layers (DL). Observed DLs are frequently accompanied by field-aligned (bi-directional) pitch angle distributions (PAD) of electrons with energies from hundred eVs up to several keV (rarely up to tens of keV). We perform numerical simulations of the DL interaction with thermal electrons making use of the test particle approach. DL parameters assumed in the simulations are adopted from observations. We show that DLs accelerate thermal electrons parallel to the magnetic field via the electrostatic Fermi mechanism, i.e. due to reflections from DL potential humps. Due to this interaction some fraction of electrons is scattered into the loss cone. The electron energy gain is larger for larger DL scalar potential amplitudes and higher propagation velocities. In addition to the Fermi mechanism electrons can be trapped by DLs in their generation region and accelerated due to transport to higher latitudes. Both mechanisms result in formation of field-aligned PADs for electrons with energies comparable to those found in observations. The Fermi mechanism provides field-aligned PADs for <1 keV electrons, while the trapping mechanism extends field-aligned PADs to higher energy electrons.

  19. A data-driven model of the generation of human EEG based on a spatially distributed stochastic wave equation.

    PubMed

    Galka, Andreas; Ozaki, Tohru; Muhle, Hiltrud; Stephani, Ulrich; Siniatchkin, Michael

    2008-06-01

    We discuss a model for the dynamics of the primary current density vector field within the grey matter of human brain. The model is based on a linear damped wave equation, driven by a stochastic term. By employing a realistically shaped average brain model and an estimate of the matrix which maps the primary currents distributed over grey matter to the electric potentials at the surface of the head, the model can be put into relation with recordings of the electroencephalogram (EEG). Through this step it becomes possible to employ EEG recordings for the purpose of estimating the primary current density vector field, i.e. finding a solution of the inverse problem of EEG generation. As a technique for inferring the unobserved high-dimensional primary current density field from EEG data of much lower dimension, a linear state space modelling approach is suggested, based on a generalisation of Kalman filtering, in combination with maximum-likelihood parameter estimation. The resulting algorithm for estimating dynamical solutions of the EEG inverse problem is applied to the task of localising the source of an epileptic spike from a clinical EEG data set; for comparison, we apply to the same task also a non-dynamical standard algorithm.

  20. Thermal electron acceleration by electric field spikes in the outer radiation belt: Generation of field-aligned pitch angle distributions

    NASA Astrophysics Data System (ADS)

    Vasko, I. Y.; Agapitov, O. V.; Mozer, F. S.; Artemyev, A. V.

    2015-10-01

    Van Allen Probes observations in the outer radiation belt have demonstrated an abundance of electrostatic electron-acoustic double layers (DL). DLs are frequently accompanied by field-aligned (bidirectional) pitch angle distributions (PAD) of electrons with energies from hundred eVs up to several keV. We perform numerical simulations of the DL interaction with thermal electrons making use of the test particle approach. DL parameters assumed in the simulations are adopted from observations. We show that DLs accelerate thermal electrons parallel to the magnetic field via the electrostatic Fermi mechanism, i.e., due to reflections from DL potential humps. The electron energy gain is larger for larger DL scalar potential amplitudes and higher propagation velocities. In addition to the Fermi mechanism, electrons can be trapped by DLs in their generation region and accelerated due to transport to higher latitudes. Both mechanisms result in formation of field-aligned PADs for electrons with energies comparable to those found in observations. The Fermi mechanism provides field-aligned PADs for <1 keV electrons, while the trapping mechanism extends field-aligned PADs to higher-energy electrons. It is shown that the Fermi mechanism can result in scattering into the loss cone of up to several tenths of percent of electrons with flux peaking at energies up to several hundred eVs.

  1. Aerosol generation and circulation in the shore zone of a Large Alpine lake - 2 - Aerosol distributions over Lake Tahoe, CA

    NASA Astrophysics Data System (ADS)

    VanCuren, R.; Pederson, J.; Lashgari, A.; Dolislager, L.; McCauley, E.

    2012-01-01

    The temporal, spatial, and size-distribution patterns of particles in ambient air over the surface of Lake Tahoe (Nevada and California) were studied as part of the 2003-2004 Lake Tahoe atmospheric deposition study (LTADS). The concentration of population along the shoreline of Lake Tahoe makes accurate characterization of local aerosol generation and transport especially important in estimation of annual particle flux to the surface of the lake. Measurements taken while cruising on the lake show that aerosol concentrations in near shore areas are primarily controlled by a combination of diurnal cycling of land- and lake- breezes and particle emissions driven by cycles of human activity near the shore. These effects were observed to be highly localized. Highest concentrations were found just offshore from urbanized areas, especially shoreline centers of activity; lowest concentrations were found along undeveloped shoreline; low-to-intermediate concentrations were measured over the middle areas of the lake. The on-lake data reported here indicate that aerosols over the lake, and thus dry deposition to the lake, are dominated by the same processes that control onshore emissions, and that the impact is strongest in the near shore areas of the lake.

  2. Two isoforms of TALDO1 generated by alternative translational initiation show differential nucleocytoplasmic distribution to regulate the global metabolic network

    PubMed Central

    Moriyama, Tetsuji; Tanaka, Shu; Nakayama, Yasumune; Fukumoto, Masahiro; Tsujimura, Kenji; Yamada, Kohji; Bamba, Takeshi; Yoneda, Yoshihiro; Fukusaki, Eiichiro; Oka, Masahiro

    2016-01-01

    Transaldolase 1 (TALDO1) is a rate-limiting enzyme involved in the pentose phosphate pathway, which is traditionally thought to occur in the cytoplasm. In this study, we found that the gene TALDO1 has two translational initiation sites, generating two isoforms that differ by the presence of the first 10 N-terminal amino acids. Notably, the long and short isoforms were differentially localised to the cell nucleus and cytoplasm, respectively. Pull-down and in vitro transport assays showed that the long isoform, unlike the short one, binds to importin α and is actively transported into the nucleus in an importin α/β-dependent manner, demonstrating that the 10 N-terminal amino acids are essential for its nuclear localisation. Additionally, we found that these two isoforms can form homo- and/or hetero-dimers with different localisation dynamics. A metabolite analysis revealed that the subcellular localisation of TALDO1 is not crucial for its activity in the pentose phosphate pathway. However, the expression of these two isoforms differentially affected the levels of various metabolites, including components of the tricarboxylic acid cycle, nucleotides, and sugars. These results demonstrate that the nucleocytoplasmic distribution of TALDO1, modulated via alternative translational initiation and dimer formation, plays an important role in a wide range of metabolic networks. PMID:27703206

  3. Final Technical Report for Contract No. DE-EE0006332, "Integrated Simulation Development and Decision Support Tool-Set for Utility Market and Distributed Solar Power Generation"

    SciTech Connect

    Cormier, Dallas; Edra, Sherwin; Espinoza, Michael; Daye, Tony; Kostylev, Vladimir; Pavlovski, Alexandre; Jelen, Deborah

    2014-12-29

    This project will enable utilities to develop long-term strategic plans that integrate high levels of renewable energy generation, and to better plan power system operations under high renewable penetration. The program developed forecast data streams for decision support and effective integration of centralized and distributed solar power generation in utility operations. This toolset focused on real time simulation of distributed power generation within utility grids with the emphasis on potential applications in day ahead (market) and real time (reliability) utility operations. The project team developed and demonstrated methodologies for quantifying the impact of distributed solar generation on core utility operations, identified protocols for internal data communication requirements, and worked with utility personnel to adapt the new distributed generation (DG) forecasts seamlessly within existing Load and Generation procedures through a sophisticated DMS. This project supported the objectives of the SunShot Initiative and SUNRISE by enabling core utility operations to enhance their simulation capability to analyze and prepare for the impacts of high penetrations of solar on the power grid. The impact of high penetration solar PV on utility operations is not only limited to control centers, but across many core operations. Benefits of an enhanced DMS using state-of-the-art solar forecast data were demonstrated within this project and have had an immediate direct operational cost savings for Energy Marketing for Day Ahead generation commitments, Real Time Operations, Load Forecasting (at an aggregate system level for Day Ahead), Demand Response, Long term Planning (asset management), Distribution Operations, and core ancillary services as required for balancing and reliability. This provided power system operators with the necessary tools and processes to operate the grid in a reliable manner under high renewable penetration.

  4. Tests of constituent-quark generation methods which maintain both the nucleon center of mass and the desired radial distribution in Monte Carlo Glauber models

    DOE PAGES

    Mitchell, J. T.; Perepelitsa, D. V.; Tannenbaum, M. J.; ...

    2016-05-23

    Here, several methods of generating three constituent quarks in a nucleon are evaluated which explicitly maintain the nucleon's center of mass and desired radial distribution and can be used within Monte Carlo Glauber frameworks. The geometric models provided by each method are used to generate distributions over the number of constituent quark participants (Nqp) in p+p,d+Au, and Au+Au collisions. The results are compared with each other and to a previous result of Nqp calculations, without this explicit constraint, used in measurements of √SNN = 200 GeV p+p,d+Au, and Au+Au collisions at the BNL Relativistic Heavy Ion Collider.

  5. Tests of constituent-quark generation methods which maintain both the nucleon center of mass and the desired radial distribution in Monte Carlo Glauber models

    NASA Astrophysics Data System (ADS)

    Mitchell, J. T.; Perepelitsa, D. V.; Tannenbaum, M. J.; Stankus, P. W.

    2016-05-01

    Several methods of generating three constituent quarks in a nucleon are evaluated which explicitly maintain the nucleon's center of mass and desired radial distribution and can be used within Monte Carlo Glauber frameworks. The geometric models provided by each method are used to generate distributions over the number of constituent quark participants (Nqp) in p +p ,d +Au , and Au +Au collisions. The results are compared with each other and to a previous result of Nqp calculations, without this explicit constraint, used in measurements of √{sNN}=200 GeV p +p ,d +Au , and Au +Au collisions at the BNL Relativistic Heavy Ion Collider.

  6. Episodic swimming in the larval zebrafish is generated by a spatially distributed spinal network with modular functional organization.

    PubMed

    Wiggin, Timothy D; Anderson, Tatiana M; Eian, John; Peck, Jack H; Masino, Mark A

    2012-08-01

    Despite the diverse methods vertebrates use for locomotion, there is evidence that components of the locomotor central pattern generator (CPG) are conserved across species. When zebrafish begin swimming early in development, they perform short episodes of activity separated by periods of inactivity. Within these episodes, the trunk flexes with side-to-side alternation and the traveling body wave progresses rostrocaudally. To characterize the distribution of the swimming CPG along the rostrocaudal axis, we performed transections of the larval zebrafish spinal cord and induced fictive swimming using N-methyl-d-aspartate (NMDA). In both intact and spinalized larvae, bursting is found throughout the rostrocaudal extent of the spinal cord, and the properties of fictive swimming observed were dependent on the concentration of NMDA. We isolated series of contiguous spinal segments by performing multiple spinal transections on the same larvae. Although series from all regions of the spinal cord have the capacity to produce bursts, the capacity to produce organized episodes of fictive swimming has a rostral bias: in the rostral spinal cord, only 12 contiguous body segments are necessary, whereas 23 contiguous body segments are necessary in the caudal spinal cord. Shorter series of segments were often active but produced either continuous rhythmic bursting or sporadic, nonrhythmic bursting. Both episodic and continuous bursting alternated between the left and right sides of the body and showed rostrocaudal progression, demonstrating the functional dissociation of the circuits responsible for episodic structure and fine burst timing. These findings parallel results in mammalian locomotion, and we propose a hierarchical model of the larval zebrafish swimming CPG.

  7. Enabling the Distributed Generation Market of High Temperature Fuel Cell and Absorption Chiller Systems to Support Critical and Commercial Loads

    NASA Astrophysics Data System (ADS)

    DiMola, Ashley M.

    Buildings account for over 18% of the world's anthropogenic Greenhouse Gas (GHG) emissions. As a result, a technology that can offset GHG emissions associated with buildings has the potential to save over 9 Giga-tons of GHG emissions per year. High temperature fuel cell and absorption chiller (HTFC/AC) technology offers a relatively low-carbon option for meeting cooling and electric loads for buildings while producing almost no criteria pollutants. GHG emissions in the state of California would decrease by 7.48 million metric tons per year if every commercial building in the State used HTFC/AC technology to meet its power and cooling requirements. In order to realize the benefits of HTFC/AC technology on a wide scale, the distributed generation market needs to be exposed to the technology and informed of its economic viability and real-world potential. This work characterizes the economics associated with HTFC/AC technology using select scenarios that are representative of realistic applications. The financial impacts of various input factors are evaluated and the HTFC/AC simulations are compared to the economics of traditional building utilities. It is shown that, in addition to the emissions reductions derived from the systems, HTFC/AC technology is financially preferable in all of the scenarios evaluated. This work also presents the design of a showcase environment, centered on a beta-test application, that presents (1) system operating data gathered using a custom data acquisition module, and (2) HTFC/AC technology in a clear and approachable manner in order to serve the target audience of market stakeholders.

  8. Second-harmonic generation of light at 544 and 272 nm from an ytterbium-doped distributed-feedback fiber laser.

    PubMed

    Herskind, Peter; Lindballe, Jens; Clausen, Christoph; Sørensen, Jens Lykke; Drewsen, Michael

    2007-02-01

    We report external cavity second-harmonic generation of light at 544 and 272 nm based on an ytterbium-doped distributed-feedback fiber laser. The nonlinear crystal used to generate light at 544 nm is LiNbO3, and the maximum output of the cavity is 845 mW, corresponding to a conversion efficiency of 55%. In a second frequency-doubling step, using a beta-BaBa2O4 crystal, we generate up to 115 mW of light at 272 nm with a conversion efficiency of 14%.

  9. Effects of source and thermal maturity on the distribution of aromatics and biomarkers in artificially generated oils

    NASA Astrophysics Data System (ADS)

    Chang, Ying-Ju

    2010-05-01

    Ying-Ju Chang (1), Wuu-Liang Huang (2), Suh-Huey Wu (3), Cheng-Lung Kuo (3) (1) Department of Geosciences, National Taiwan University, Taipei, Taiwan (r93224103@ntu.edu.tw); (2) Department of Geosciences, National Taiwan University, Taipei, Taiwan; (3) Exploration and Development Research Institute, Chinese Petroleum Corp., Taiwan Oils generated from isolated kerogens from a variety of source rocks, including two marine shales, two terrestrial coals, and three lacustrine oil shales were characterized for the effects of source and maturity on the distributions of hydrocarbons compounds. Experiments were conducted by confined pressure (gold-tube) pyrolysis at 320 deg. Celsius at four laboratory maturities (0.79, 0.95, 1.10, 1.34 Easy%Ro). The results show that normal alkane distribution in oils from different kerogens exhibit distinct preference in carbon number and predominance in specific compounds. The carbon preference index (CPI) and odd-even predominance (OEP) ratios tend to approach to 1 with increasing maturity. Oils from two terrestrial kerogens show higher Pr/n-C17 ratio than lacustrine kerogens (Green-river oil shale, GR) and vice versa for Ph/n-C18 ratio. Both ratios decrease with increasing maturity but show distinct trends for different kerogens. The (Pr/n-C17) and (Ph/n-C18) ratios for the lamosite, torbanite, and two marine kerogens are very low at all studied maturities. The pristane/phytane (Pr/Ph) and [(Pr/C17)/(Ph/C18)] ratios in oils from three major kerogen types vary barely with maturity but are discernible in diverse organic types, implying good source indication. The methylphenanthrene ratios (MPR) for most kerogens, which vary significantly only at maturities higher than 1.0 %Ro, are suitable for high maturity indication. The methylphenanthrene distribution fraction (MPDF), in general, increases slightly with increasing maturity, except in torbanite. The MPDF parameter for GR kerogen exhibits best linear correlation with maturity whereas

  10. One-laser-based generation/detection of Brillouin dynamic grating and its application to distributed discrimination of strain and temperature.

    PubMed

    Zou, Weiwen; He, Zuyuan; Hotate, Kazuo

    2011-01-31

    This paper presents a novel scheme to generate and detect Brillouin dynamic grating in a polarization-maintaining optical fiber based on one laser source. Precise measurement of Brillouin dynamic grating spectrum is achieved benefiting from that the pump, probe and readout waves are coherently originated from the same laser source. Distributed discrimination of strain and temperature is also achieved with high accuracy.

  11. Simultaneous visualization of oxygen partial pressure, current density, and water droplets in serpentine fuel cell during power generation for understanding reaction distributions

    NASA Astrophysics Data System (ADS)

    Takanohashi, Kazuhiro; Suga, Takeo; Uchida, Makoto; Ueda, Toshihide; Nagumo, Yuzo; Inukai, Junji; Nishide, Hiroyuki; Watanabe, Masahiro

    2017-03-01

    Understanding the reaction distributions inside a polymer electrolyte fuel cell (PEFC) is essential for the higher performance and durability. We have developed a new see-through cell and visualized the distributions of oxygen partial pressure and current density inside a running PEFC at the temperature of 40 and 80 °C and the relative humidity of 53%. The oxygen utilization was changed from 0% to 80% by changing the current density. At higher oxygen utilizations, the current density was higher and therefore the water generation. Generated water droplets in the flow channel were also visualized, allowing for the simultaneous visualization of the distribution of the oxygen partial pressure, current density, and water droplets. By combining the observations of all three parameters, the reactions inside a membrane-electrode assembly were discussed.

  12. Physically-based distributed hydrologic modeling of tropical catchments: Hypothesis testing on model formation and runoff generation

    NASA Astrophysics Data System (ADS)

    Abebe, N. A.; Ogden, F. L.

    2011-12-01

    Watersheds vary in their nature based on their geographic location, altitude, climate, geology, soils, and land use/land cover. These variations lead to differences in the conceptualization and formulation of hydrological models intended to represent the expected hydrological processes in a given catchment. Watersheds in the tropics are characterized by intensive and persistent biological activity and a large amount of rainfall. Our study focuses on the Agua Salud project catchments located in the Panama Canal Watershed, Panama, which have steep rolling topography, deep soils derived from weathered bedrock, and limited exposed bedrock. These catchments are also highly affected by soil cracks, decayed tree roots and animal burrows that form a network of preferential flow paths. One hypothesis is that these macropores conduct interflow during heavy rainfall, when a transient perched water table forms at a depth where the vertical hydraulic conductivity is significantly reduced near the bottom of the bioturbation layer. We have developed a physics-based, spatially distributed, multi-layered hydrologic model to simulate the dominant flow processes, including overland flow, channel flow, vertical matrix and non-Richards film flow, lateral downslope saturated matrix and non-Darcian pipe flow in the bioturbation layer and deep saturated groundwater flow. In our model formulation, we use the model to examine a variety of hydrological processes which we anticipate may occur. Emphasis is given to the modeling of the soil moisture dynamics in the bioturbation layer, development of lateral preferential flow and activation of the macropores and exchange of water at the interface between a bioturbation layer and a second layer below it. We consider interactions between surface water, ground water, channel water and perched water in the riparian zone cells with the aim of understanding likely runoff generation mechanisms. Results show that inclusion of as many different flow

  13. Next-Generation Angular Distribution Models for Top-of-Atmosphere Radiative Flux Calculation from the CERES Instruments: Methodology

    NASA Technical Reports Server (NTRS)

    Su, W.; Corbett, J.; Eitzen, Z.; Liang, L.

    2015-01-01

    The top-of-atmosphere (TOA) radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and the Earth's Radiant Energy System (CERES) instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene-type-dependent angular distribution models (ADMs). This paper describes the next-generation ADMs that are developed for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements. Coincident cloud and aerosol retrievals, and radiance measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from Goddard Earth Observing System (GEOS) data assimilation version 5.4.1 are used to define scene type. CERES radiance measurements are stratified by scene type and by other parameters that are important for determining the anisotropy of the given scene type. Anisotropic factors are then defined either for discrete intervals of relevant parameters or as a continuous functions of combined parameters, depending on the scene type. Significant differences between the ADMs described in this paper and the existing ADMs are over clear-sky scene types and polar scene types. Over clear ocean, we developed a set of shortwave (SW) ADMs that explicitly account for aerosols. Over clear land, the SW ADMs are developed for every 1 latitude1 longitude region for every calendar month using a kernel-based bidirectional reflectance model. Over clear Antarctic scenes, SW ADMs are developed by accounting the effects of sastrugi on anisotropy. Over sea ice, a sea-ice brightness index is used to classify the scene type. Under cloudy conditions over all surface types, the longwave (LW) and window (WN) ADMs are developed by combining surface and cloud-top temperature, surface and cloud emissivity, cloud fraction, and precipitable water

  14. Next-generation angular distribution models for top-of-atmosphere radiative flux calculation from CERES instruments: methodology

    NASA Astrophysics Data System (ADS)

    Su, W.; Corbett, J.; Eitzen, Z.; Liang, L.

    2015-02-01

    The top-of-atmosphere (TOA) radiative fluxes are critical components to advancing our understanding of the Earth's radiative energy balance, radiative effects of clouds and aerosols, and climate feedback. The Clouds and the Earth's Radiant Energy System (CERES) instruments provide broadband shortwave and longwave radiance measurements. These radiances are converted to fluxes by using scene-type-dependent angular distribution models (ADMs). This paper describes the next-generation ADMs that are developed for Terra and Aqua using all available CERES rotating azimuth plane radiance measurements. Coincident cloud and aerosol retrievals, and radiance measurements from the Moderate Resolution Imaging Spectroradiometer (MODIS), and meteorological parameters from Goddard Earth Observing System (GEOS) data assimilation version 5.4.1 are used to define scene type. CERES radiance measurements are stratified by scene type and by other parameters that are important for determining the anisotropy of the given scene type. Anisotropic factors are then defined either for discrete intervals of relevant parameters or as a continuous functions of combined parameters, depending on the scene type. Significant differences between the ADMs described in this paper and the existing ADMs are over clear-sky scene types and polar scene types. Over clear ocean, we developed a set of shortwave (SW) ADMs that explicitly account for aerosols. Over clear land, the SW ADMs are developed for every 1° latitude × 1° longitude region for every calendar month using a kernel-based bidirectional reflectance model. Over clear Antarctic scenes, SW ADMs are developed by accounting the effects of sastrugi on anisotropy. Over sea ice, a sea-ice brightness index is used to classify the scene type. Under cloudy conditions over all surface types, the longwave (LW) and window (WN) ADMs are developed by combining surface and cloud-top temperature, surface and cloud emissivity, cloud fraction, and precipitable

  15. Global model analysis of negative ion generation in low-pressure inductively coupled hydrogen plasmas with bi-Maxwellian electron energy distributions

    SciTech Connect

    Huh, Sung-Ryul; Kim, Nam-Kyun; Jung, Bong-Ki; Chung, Kyoung-Jae; Hwang, Yong-Seok; Kim, Gon-Ho

    2015-03-15

    A global model was developed to investigate the densities of negative ions and the other species in a low-pressure inductively coupled hydrogen plasma with a bi-Maxwellian electron energy distribution. Compared to a Maxwellian plasma, bi-Maxwellian plasmas have higher populations of low-energy electrons and highly vibrationally excited hydrogen molecules that are generated efficiently by high-energy electrons. This leads to a higher reaction rate of the dissociative electron attachment responsible for negative ion production. The model indicated that the bi-Maxwellian electron energy distribution at low pressures is favorable for the creation of negative ions. In addition, the electron temperature, electron density, and negative ion density calculated using the model were compared with the experimental data. In the low-pressure regime, the model results of the bi-Maxwellian electron energy distributions agreed well quantitatively with the experimental measurements, unlike those of the assumed Maxwellian electron energy distributions that had discrepancies.

  16. Smooth, seamless, and structured grid generation with flexibility in resolution distribution on a sphere based on conformal mapping and the spring dynamics method

    NASA Astrophysics Data System (ADS)

    Iga, Shin-ichi

    2015-09-01

    A generation method for smooth, seamless, and structured triangular grids on a sphere with flexibility in resolution distribution is proposed. This method is applicable to many fields that deal with a sphere on which the required resolution is not uniform. The grids were generated using the spring dynamics method, and adjustments were made using analytical functions. The mesh topology determined its resolution distribution, derived from a combination of conformal mapping factors: polar stereographic projection (PSP), Lambert conformal conic projection (LCCP), and Mercator projection (MP). Their combination generated, for example, a tropically fine grid that had a nearly constant high-resolution belt around the equator, with a gradual decrease in resolution distribution outside of the belt. This grid can be applied to boundary-less simulations of tropical meteorology. The other example involves a regionally fine grid with a nearly constant high-resolution circular region and a gradually decreasing resolution distribution outside of the region. This is applicable to regional atmospheric simulations without grid nesting. The proposed grids are compatible with computer architecture because they possess a structured form. Each triangle of the proposed grids was highly regular, implying a high local isotropy in resolution. Finally, the proposed grids were examined by advection and shallow water simulations.

  17. In situ diagnostic of the size distribution of nanoparticles generated by ultrashort pulsed laser ablation in vacuum

    SciTech Connect

    Bourquard, Florent; Loir, Anne-Sophie; Donnet, Christophe; Garrelie, Florence

    2014-03-10

    We aim to characterize the size distribution of nanoparticles located in the ablation plume produced by femtosecond laser interaction. The proposed method relies on the use of white-light extinction spectroscopy setup assisted by ultrafast intensified temporal gating. This method allows measurement of optical absorbance of a nickel nanoparticles cloud. Simulation of the extinction section of nickel nanoparticles size distributions has been developed in order to compare the measured optical absorbance to the optical extinction by theoretical and experimental nanoparticles size distributions (measured by scanning electron microscopy). A good agreement has been found between the in situ measured optical absorbance and the optical extinction cross section calculated from ex situ nanoparticles size distribution measurements.

  18. Dependence of Ozone Generation on Gas Temperature Distribution in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen

    NASA Astrophysics Data System (ADS)

    Takahashi, Go; Akashi, Haruaki

    AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are main streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated mainly in the vicinity of the dielectrics. In high gas temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high gas temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of gas temperature was neglected, amount of ozone generation increases 10%.

  19. The Effect of Limited Sample Sizes on the Accuracy of the Estimated Scaling Parameter for Power-Law-Distributed Solar Data

    NASA Astrophysics Data System (ADS)

    D'Huys, Elke; Berghmans, David; Seaton, Daniel B.; Poedts, Stefaan

    2016-05-01

    Many natural processes exhibit a power-law behavior. The power-law exponent is linked to the underlying physical process, and therefore its precise value is of interest. With respect to the energy content of nanoflares, for example, a power-law exponent steeper than 2 is believed to be a necessary condition for solving the enigmatic coronal heating problem. Studying power-law distributions over several orders of magnitudes requires sufficient data and appropriate methodology. In this article we demonstrate the shortcomings of some popular methods in solar physics that are applied to data of typical sample sizes. We use synthetic data to study the effect of the sample size on the performance of different estimation methods. We show that vast amounts of data are needed to obtain a reliable result with graphical methods (where the power-law exponent is estimated by a linear fit on a log-transformed histogram of the data). We revisit published results on power laws for the angular width of solar coronal mass ejections and the radiative losses of nanoflares. We demonstrate the benefits of the maximum likelihood estimator and advocate its use.

  20. Quantum Hash function and its application to privacy amplification in quantum key distribution, pseudo-random number generation and image encryption

    PubMed Central

    Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min

    2016-01-01

    Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information. PMID:26823196

  1. Tests of constituent-quark generation methods which maintain both the nucleon center of mass and the desired radial distribution in Monte Carlo Glauber models

    SciTech Connect

    Mitchell, J. T.; Perepelitsa, D. V.; Tannenbaum, M. J.; Stankus, P. W.

    2016-05-23

    Here, several methods of generating three constituent quarks in a nucleon are evaluated which explicitly maintain the nucleon's center of mass and desired radial distribution and can be used within Monte Carlo Glauber frameworks. The geometric models provided by each method are used to generate distributions over the number of constituent quark participants (Nqp) in p+p,d+Au, and Au+Au collisions. The results are compared with each other and to a previous result of Nqp calculations, without this explicit constraint, used in measurements of √SNN = 200 GeV p+p,d+Au, and Au+Au collisions at the BNL Relativistic Heavy Ion Collider.

  2. Multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution as a mechanism to generate intermediate band energy levels

    NASA Astrophysics Data System (ADS)

    Rodríguez-Magdaleno, K. A.; Pérez-Álvarez, R.; Martínez-Orozco, J. C.; Pernas-Salomón, R.

    2017-04-01

    In this work the generation of an intermediate band of energy levels from multi-shell spherical GaAs /AlxGa1-x As quantum dot shells-size distribution is reported. Within the effective mass approximation the electronic structure of a GaAs spherical quantum-dot surrounded by one, two and three shells is studied in detail using a numerically stable transfer matrix method. We found that a shells-size distribution characterized by continuously wider GaAs domains is a suitable mechanism to generate the intermediate band whose width is also dependent on the Aluminium concentration x. Our results suggest that this effective mechanism can be used for the design of wider intermediate band than reported in other quantum systems with possible solar cells enhanced performance.

  3. Quantum Hash function and its application to privacy amplification in quantum key distribution, pseudo-random number generation and image encryption.

    PubMed

    Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min

    2016-01-29

    Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information.

  4. Quantum Hash function and its application to privacy amplification in quantum key distribution, pseudo-random number generation and image encryption

    NASA Astrophysics Data System (ADS)

    Yang, Yu-Guang; Xu, Peng; Yang, Rui; Zhou, Yi-Hua; Shi, Wei-Min

    2016-01-01

    Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information.

  5. Do bacterial cell numbers follow a theoretical Poisson distribution? Comparison of experimentally obtained numbers of single cells with random number generation via computer simulation.

    PubMed

    Koyama, Kento; Hokunan, Hidekazu; Hasegawa, Mayumi; Kawamura, Shuso; Koseki, Shigenobu

    2016-12-01

    We investigated a bacterial sample preparation procedure for single-cell studies. In the present study, we examined whether single bacterial cells obtained via 10-fold dilution followed a theoretical Poisson distribution. Four serotypes of Salmonella enterica, three serotypes of enterohaemorrhagic Escherichia coli and one serotype of Listeria monocytogenes were used as sample bacteria. An inoculum of each serotype was prepared via a 10-fold dilution series to obtain bacterial cell counts with mean values of one or two. To determine whether the experimentally obtained bacterial cell counts follow a theoretical Poisson distribution, a likelihood ratio test between the experimentally obtained cell counts and Poisson distribution which parameter estimated by maximum likelihood estimation (MLE) was conducted. The bacterial cell counts of each serotype sufficiently followed a Poisson distribution. Furthermore, to examine the validity of the parameters of Poisson distribution from experimentally obtained bacterial cell counts, we compared these with the parameters of a Poisson distribution that were estimated using random number generation via computer simulation. The Poisson distribution parameters experimentally obtained from bacterial cell counts were within the range of the parameters estimated using a computer simulation. These results demonstrate that the bacterial cell counts of each serotype obtained via 10-fold dilution followed a Poisson distribution. The fact that the frequency of bacterial cell counts follows a Poisson distribution at low number would be applied to some single-cell studies with a few bacterial cells. In particular, the procedure presented in this study enables us to develop an inactivation model at the single-cell level that can estimate the variability of survival bacterial numbers during the bacterial death process.

  6. Theoretical Studies and Experimental Validation for Generating Concentration Distributions Across the Propellant Grain Upon Shear-Induced Particle Migration During Extrusion

    DTIC Science & Technology

    2007-06-01

    using Poiseuille flow in a rectangular die. It appears that the functionally-grading of propellant strands can be generated upon shear-induced...the suggested methodologies and their practicality. 15. SUBJECT TERMS Functionally graded propellant Shear-induced migration Poiseuille flow Couette...or a circular tube with radius R 9 8 Fully developed concentration distribution for steady state Poiseuille flow 11 9 Particle concentration

  7. Butterfly Pitch Angle Distributions Generated at Low L Values During March 2015 Storm: Van Allen Probe ECT Observations

    NASA Astrophysics Data System (ADS)

    Fennell, J. F.; Kanekal, S.; Claudepierre, S. G.; Blake, J. B.; O'Brien, T. P., III; Turner, D. L.; Baker, D. N.; Spence, H. E.; Geoffrey, R.

    2015-12-01

    The 17 March 2015 magnetic storm was the largest storm (DST<-220 nT) in the Van Allen Probes era so far. Near the end of the main phase and during the early recovery phase of this storm the ECT MagEIS and REPT sensors observed electrons with "butterfly" type pitch angle distributions with relative minima at 90° equatorial pitch angles. The "butterfly" distributions were observed at energies that spanned the range from 32 keV to ~5 MeV. These pitch angle distributions occurred over an energy- dependent range of L-shells from L~1.5 in the inner zone out to L~3 in the slot region. In general, they occurred at the deepest L penetration point for the individual energies. We will present these observations and discuss their relationship to earlier observations and recently published simulation results.

  8. Biomarker distribution of source rocks in the dongpu depression and its relation to the generation of immature oil

    NASA Astrophysics Data System (ADS)

    Jiyang, Shi; Mingju, Xiang; Zhiqing, Hong; Benshan, Wang; Lijie, Zhang; Maoan, Xin

    In order to understand thermal stabilities of various biomarkers in sedimentary rocks, and to utilize them to subdivide the stage of diagenesis and to define the immature oil-generating threshold in the eastern part of China, serial cores from various depths and core samples from well WHI-I, heated in a simulation experiment at various temperatures, have been analysed. As a result, the relative thermal stabilities for alkybenzenes, alkylithophenes, benzohopanes, hopenes, diasterenes, ββ-hopanes, steranes and terpanes have been recognized and it has been suggested that the immature oil-generating threshold could be defined at the depth at which there are no hopenes in sedimentary rocks.

  9. Community-Based Social Networks: Generation of Power Law Degree Distribution and IP Solutions to the KPP

    ERIC Educational Resources Information Center

    Wu, Wentao

    2012-01-01

    The objective of this thesis is two-fold: (1) to investigate the degree distribution property of community-based social networks (CSNs) and (2) to provide solutions to a pertinent problem, the Key Player Problem. In the first part of this thesis, we consider a growing community-based network in which the ability of nodes competing for links to new…

  10. Generative Leadership: A Case Study of Distributed Leadership and Leadership Sustainability at Two New York City High Schools

    ERIC Educational Resources Information Center

    Lynch, Olivia

    2009-01-01

    Generative Leadership is a case study of how two New York City High Schools sustain and develop leadership. The study explores their system of school governance, its rationale and beliefs, the leadership structures and how their collaborative leadership practice insures that no leader stands alone and that replacement leadership is available at…

  11. Estimation of synthetic flood design hydrographs using a distributed rainfall-runoff model coupled with a copula-based single storm rainfall generator

    NASA Astrophysics Data System (ADS)

    Candela, A.; Brigandì, G.; Aronica, G. T.

    2014-07-01

    In this paper a procedure to derive synthetic flood design hydrographs (SFDH) using a bivariate representation of rainfall forcing (rainfall duration and intensity) via copulas, which describes and models the correlation between two variables independently of the marginal laws involved, coupled with a distributed rainfall-runoff model, is presented. Rainfall-runoff modelling (R-R modelling) for estimating the hydrological response at the outlet of a catchment was performed by using a conceptual fully distributed procedure based on the Soil Conservation Service - Curve Number method as an excess rainfall model and on a distributed unit hydrograph with climatic dependencies for the flow routing. Travel time computation, based on the distributed unit hydrograph definition, was performed by implementing a procedure based on flow paths, determined from a digital elevation model (DEM) and roughness parameters obtained from distributed geographical information. In order to estimate the primary return period of the SFDH, which provides the probability of occurrence of a hydrograph flood, peaks and flow volumes obtained through R-R modelling were treated statistically using copulas. Finally, the shapes of hydrographs have been generated on the basis of historically significant flood events, via cluster analysis. An application of the procedure described above has been carried out and results presented for the case study of the Imera catchment in Sicily, Italy.

  12. Electromagnetic Scattering by an Exponentially Distributed Rough Surface with the Introduction of a Rough Surface Generation Technique

    DTIC Science & Technology

    1987-12-01

    60 3. Summary .................. ....................... 73 Part B . I. The Generation of Random Rough Surfaces (Background) 74 2. The RCS Program...A.1: Solution of Integrals from Appendix A ...... ... 108 Appendix B : A Closed Form Solution for the First Series of the Exponential Characteristic...of a surface represented by Pyati’s exponential jpdf using somewhat traditional rough surface scattering theory. Part B involves the development of an

  13. Distribution of tributyltin, dibutyltin and monobutyltin in the liver, brain and fat of rats: two-generation toxicity study of tributyltin chloride.

    PubMed

    Omura, Minoru; Shimasaki, Youhei; Oshima, Yuji; Nakayama, Kei; Kubo, Kazuhiko; Aou, Shuji; Ogata, Rika; Hirata, Miyuki; Inoue, Naohide

    2004-01-01

    The distribution of tributyltin (TBT) and its metabolites, dibutyltin (DBT) and monobutyltin (MBT), was examined in the liver, brain and fat tissues in a two-generation reproductive toxicity study of tributyltin chloride (TBTCl) in rats using dietary supplementation at concentrations of 5, 25 and 125 ppm. In the liver, irrespective of TBTCl dietary concentration, gender or generation, the highest concentration of metabolite was consistently MBT, followed by DBT, and then TBT. In contrast, TBT was consistently present at the highest concentration in the brain, nearly always followed by DBT and MBT. In fat tissues, the concentrations of the three butyltin compounds showed similar relationships to those observed in the brain, although the concentrations were much lower. In the liver, the concentration of TBT was higher in females, and those of DBT and MBT were higher in males. Factorial ANOVA also suggested the effect of gender on the concentrations of the three butyltin compounds in the liver. The results of this study suggest tissue-dependent distribution of TBT, DBT and MBT and gender-dependent distribution of the three metabolites in the liver of rats.

  14. Net Metering Policy Development and Distributed Solar Generation in Minnesota: Overview of Trends in Nationwide Policy Development and Implications of Increasing the Eligible System Size Cap

    SciTech Connect

    Doris, E.; Busche, S.; Hockett, S.

    2009-12-01

    The goal of the Minnesota net metering policy is to give the maximum possible encouragement to distributed generation assets, especially solar electric systems (MN 2008). However, according to a published set of best practices (NNEC 2008) that prioritize the maximum development of solar markets within states, the Minnesota policy does not incorporate many of the important best practices that may help other states transform their solar energy markets and increase the amount of grid-connected distributed solar generation assets. Reasons cited include the low system size limit of 40kW (the best practices document recommends a 2 MW limit) and a lack of language protecting generators from additional utility fees. This study was conducted to compare Minnesota's policies to national best practices. It provides an overview of the current Minnesota policy in the context of these best practices and other jurisdictions' net metering policies, as well as a qualitative assessment of the impacts of raising the system size cap within the policy based on the experiences of other states.

  15. Procedure of calculation of the spatial distribution of temperatures and heat fluxes in the steam generator of a nuclear power installation with an RBEC fast-neutron reactor

    NASA Astrophysics Data System (ADS)

    Frolov, A. A.; Sedov, A. A.

    2016-08-01

    A method for combined 3D/1D-modeling of thermohydraulics of a once-through steam generator (SG) based on the joint analysis of three-dimensional thermo- and hydrodynamics of a single-phase heating coolant in the intertube space and one-dimensional thermohydraulics of steam-generating channels (tubes) with the use of well-known friction and heat-transfer correlations under various boiling conditions is discussed. This method allows one to determine the spatial distribution of temperatures and heat fluxes of heat-exchange surfaces of SGs with a single-phase heating coolant in the intertube space and with steam generation within tubes. The method was applied in the analytical investigation of typical operation of a once-through SG of a nuclear power installation with an RBEC fast-neutron heavy-metal reactor that is being designed by Kurchatov Institute in collaboration with OKB GIDROPRESS and Leipunsky Institute of Physics and Power Engineering. Flow pattern and temperature fields were obtained for the heavy-metal heating coolant in the intertube space. Nonuniformities of heating of the steam-water coolant in different heat-exchange tubes and nonuniformities in the distribution of heat fluxes at SG heat-exchange surfaces were revealed.

  16. ESPRESSO instrument control electronics: a PLC based distributed layout for a second generation instrument at ESO VLT

    NASA Astrophysics Data System (ADS)

    Baldini, V.; Cirami, R.; Coretti, I.; Cristiani, S.; Di Marcantonio, P.; Mannetta, M.; Santin, P.; Mégevand, D.; Zerbi, F.

    2014-07-01

    ESPRESSO is an ultra-stable fiber-fed spectrograph designed to combine incoherently the light coming from up to 4 Unit Telescopes of the ESO VLT. From the Nasmyth focus of each telescope the light, through an optical path, is fed by the Coudé Train subsystems to the Front End Unit placed in the Combined Coudé Laboratory. The Front End is composed by one arm for each telescope and its task is to convey the incoming light, after a calibration process, into the spectrograph fibers. To perform these operations a large number of functions are foreseen, like motorized stages, lamps, digital and analog sensors that, coupled with dedicated Technical CCDs (two per arms), allow to stabilize the incoming beam up to the level needed to exploit the ESPRESSO scientific requirements. The Instrument Control Electronics goal is to properly control all the functions in the Combined Coudé Laboratory and the spectrograph itself. It is fully based on a distributed PLC architecture, abandoning in this way the VME-based technology previously adopted for the ESO VLT instruments. In this paper we will describe the ESPRESSO Instrument Control Electronics architecture, focusing on the distributed layout and its interfaces with the other ESPRESSO subsystems.

  17. Sub-5-ps optical pulse generation from a 1.55-µm distributed-feedback laser diode with nanosecond electric pulse excitation and spectral filtering.

    PubMed

    Chen, Shaoqiang; Sato, Aya; Ito, Takashi; Yoshita, Masahiro; Akiyama, Hidefumi; Yokoyama, Hiroyuki

    2012-10-22

    This paper reports generation of sub-5-ps Fourier-transform limited optical pulses from a 1.55-µm gain-switched single-mode distributed-feedback laser diode via nanosecond electric excitation and a simple spectral-filtering technique. Typical damped oscillations of the whole lasing spectrum were observed in the time-resolved waveform. Through a spectral-filtering technique, the initial relaxation oscillation pulse and the following components in the output pulse can be well separated, and the initial short pulse can be selectively extracted by filtering out the short-wavelength components in the spectrum. Short pulses generated by this simple method are expected to have wide potential applications comparable to mode-locking lasers.

  18. The allele distribution in next-generation sequencing data sets is accurately described as the result of a stochastic branching process.

    PubMed

    Heinrich, Verena; Stange, Jens; Dickhaus, Thorsten; Imkeller, Peter; Krüger, Ulrike; Bauer, Sebastian; Mundlos, Stefan; Robinson, Peter N; Hecht, Jochen; Krawitz, Peter M

    2012-03-01

    With the availability of next-generation sequencing (NGS) technology, it is expected that sequence variants may be called on a genomic scale. Here, we demonstrate that a deeper understanding of the distribution of the variant call frequencies at heterozygous loci in NGS data sets is a prerequisite for sensitive variant detection. We model the crucial steps in an NGS protocol as a stochastic branching process and derive a mathematical framework for the expected distribution of alleles at heterozygous loci before measurement that is sequencing. We confirm our theoretical results by analyzing technical replicates of human exome data and demonstrate that the variance of allele frequencies at heterozygous loci is higher than expected by a simple binomial distribution. Due to this high variance, mutation callers relying on binomial distributed priors are less sensitive for heterozygous variants that deviate strongly from the expected mean frequency. Our results also indicate that error rates can be reduced to a greater degree by technical replicates than by increasing sequencing depth.

  19. Fuel Cell Power Model Version 2: Startup Guide, System Designs, and Case Studies. Modeling Electricity, Heat, and Hydrogen Generation from Fuel Cell-Based Distributed Energy Systems

    SciTech Connect

    Steward, D.; Penev, M.; Saur, G.; Becker, W.; Zuboy, J.

    2013-06-01

    This guide helps users get started with the U.S. Department of Energy/National Renewable Energy Laboratory Fuel Cell Power (FCPower) Model Version 2, which is a Microsoft Excel workbook that analyzes the technical and economic aspects of high-temperature fuel cell-based distributed energy systems with the aim of providing consistent, transparent, comparable results. This type of energy system would provide onsite-generated heat and electricity to large end users such as hospitals and office complexes. The hydrogen produced could be used for fueling vehicles or stored for later conversion to electricity.

  20. Hundred-watt-level high power random distributed feedback Raman fiber laser at 1150 nm and its application in mid-infrared laser generation.

    PubMed

    Zhang, Hanwei; Zhou, Pu; Wang, Xiong; Du, Xueyuan; Xiao, Hu; Xu, Xiaojun

    2015-06-29

    Two kinds of hundred-watt-level random distributed feedback Raman fiber have been demonstrated. The optical efficiency can reach to as high as 84.8%. The reported power and efficiency of the random laser is the highest one as we know. We have also demonstrated that the developed random laser can be further used to pump a Ho-doped fiber laser for mid-infrared laser generation. Finally, 23 W 2050 nm laser is achieved. The presented laser can obtain high power output efficiently and conveniently and opens a new direction for high power laser sources at designed wavelength.

  1. Electron two-stream instability and its application in solar and heliophysics

    NASA Astrophysics Data System (ADS)

    Che, Haihong

    2016-06-01

    It is well known that electron beams accelerated in solar flares can drive two-stream instability and produce radio bursts in the solar corona as well as in the interplanetary medium. Recent observations show that the solar wind likely originates from nanoflare-like events near the surface of the Sun where locally heated plasma escapes along open field lines into space. Recent numerical simulations and theoretical studies show that electron two-stream instability (ETSI) driven by nanoflare-accelerated electron beams can produce the observed nanoflare-type radio bursts, the non-Maxwellian electron velocity distribution function of the solar wind, and the kinetic scale turbulence in solar wind. This brief review focus on the basic theoretical framework and recent progress in the nonlinear evolution of ETSI driven by electron beams, including the formation of electron holes, Langmuir wave generation in warm plasma, and the nonlinear modulation instability and Langmuir collapse. Potential applications in heliophysics and astrophysics are discussed.

  2. Regimes of Generation in Low-Q Distributed-Feedback Lasers with Strong Inhomogeneous Broadening of the Active Medium

    NASA Astrophysics Data System (ADS)

    Kocharovskaya, E. R.; Ginzburg, N. S.; Sergeev, A. S.; Kocharovsky, V. V.; Kocharovsky, Vl. V.

    2016-11-01

    We study the influence of the ratio between the relaxation rates of the field in a cavity and the polarization of active centers on the dynamic properties of the distributed-feedback lasers by means of 1D numerical simulation. The model of a two-level active medium with strong inhomogeneous broadening of the spectral line under CW wide-band pumping that provides two- or several-mode lasing in the vicinity of the Bragg photonic band gap is used. Evolution of the dynamic spectra and oscillograms of the laser emission with decreasing Q-factor of the Bragg resonator is analyzed. It is shown, in particular, that under conditions of the dominant role of the superradiant effects, there are unique opportunities for control of both quantitative and qualitative characteristics of lasing, including the spectral width, duration, and coherence length of various pulse components of the output radiation.

  3. Energy solutions in rural Africa: mapping electrification costs of distributed solar and diesel generation versus grid extension

    NASA Astrophysics Data System (ADS)

    Szabó, S.; Bódis, K.; Huld, T.; Moner-Girona, M.

    2011-07-01

    Three rural electrification options are analysed showing the cost optimal conditions for a sustainable energy development applying renewable energy sources in Africa. A spatial electricity cost model has been designed to point out whether diesel generators, photovoltaic systems or extension of the grid are the least-cost option in off-grid areas. The resulting mapping application offers support to decide in which regions the communities could be electrified either within the grid or in an isolated mini-grid. Donor programs and National Rural Electrification Agencies (or equivalent governmental departments) could use this type of delineation for their program boundaries and then could use the local optimization tools adapted to the prevailing parameters. The views expressed in this paper are those of the authors and do not necessarily represent European Commission and UNEP policy.

  4. Population Distribution of Beta-Lactamase Conferring Resistance to Third-Generation Cephalosporins in Human Clinical Enterobacteriaceae in The Netherlands

    PubMed Central

    Voets, Guido M.; Platteel, Tamara N.; Fluit, Ad C.; Scharringa, Jelle; Schapendonk, Claudia M.; Stuart, James Cohen; Bonten, Marc J. M.; Hall, Maurine A. L.

    2012-01-01

    There is a global increase in infections caused by Enterobacteriaceae with plasmid-borne β-lactamases that confer resistance to third-generation cephalosporins. The epidemiology of these bacteria is not well understood, and was, therefore, investigated in a selection of 636 clinical Enterobacteriaceae with a minimal inhibitory concentration >1 mg/L for ceftazidime/ceftriaxone from a national survey (75% E. coli, 11% E. cloacae, 11% K. pneumoniae, 2% K. oxytoca, 2% P. mirabilis). Isolates were investigated for extended-spectrum β-lactamases (ESBLs) and ampC genes using microarray, PCR, gene sequencing and molecular straintyping (Diversilab and multi-locus sequence typing (MLST)). ESBL genes were demonstrated in 512 isolates (81%); of which 446 (87%) belonged to the CTX-M family. Among 314 randomly selected and sequenced isolates, blaCTX-M-15 was most prevalent (n = 124, 39%), followed by blaCTX-M-1 (n = 47, 15%), blaCTX-M-14 (n = 15, 5%), blaSHV-12 (n = 24, 8%) and blaTEM-52 (n = 13, 4%). Among 181 isolates with MIC ≥16 mg/L for cefoxitin plasmid encoded AmpCs were detected in 32 and 27 were of the CMY-2 group. Among 102 E. coli isolates with MIC ≥16 mg/L for cefoxitin ampC promoter mutations were identified in 29 (28%). Based on Diversilab genotyping of 608 isolates (similarity cut-off >98%) discriminatory indices of bacteria with ESBL and/or ampC genes were 0.994, 0.985 and 0.994 for E. coli, K. pneumoniae and E. cloacae, respectively. Based on similarity cut-off >95% two large clusters of E. coli were apparent (of 43 and 30 isolates) and 21 of 21 that were typed by belonged to ST131 of which 13 contained blaCTX-M-15. Our findings demonstrate that blaCTX-M-15 is the most prevalent ESBL and we report a larger than previously reported prevalence of ampC genes among Enterobacteriaceae responsible for resistance to third-generation cephalosporins. PMID:23284886

  5. Population distribution of Beta-lactamase conferring resistance to third-generation cephalosporins in human clinical Enterobacteriaceae in the Netherlands.

    PubMed

    Voets, Guido M; Platteel, Tamara N; Fluit, Ad C; Scharringa, Jelle; Schapendonk, Claudia M; Stuart, James Cohen; Bonten, Marc J M; Leverstein-van Hall, Maurine A; Hall, Maurine A L

    2012-01-01

    There is a global increase in infections caused by Enterobacteriaceae with plasmid-borne β-lactamases that confer resistance to third-generation cephalosporins. The epidemiology of these bacteria is not well understood, and was, therefore, investigated in a selection of 636 clinical Enterobacteriaceae with a minimal inhibitory concentration >1 mg/L for ceftazidime/ceftriaxone from a national survey (75% E. coli, 11% E. cloacae, 11% K. pneumoniae, 2% K. oxytoca, 2% P. mirabilis). Isolates were investigated for extended-spectrum β-lactamases (ESBLs) and ampC genes using microarray, PCR, gene sequencing and molecular straintyping (Diversilab and multi-locus sequence typing (MLST)). ESBL genes were demonstrated in 512 isolates (81%); of which 446 (87%) belonged to the CTX-M family. Among 314 randomly selected and sequenced isolates, bla(CTX-M-15) was most prevalent (n = 124, 39%), followed by bla(CTX-M-1) (n = 47, 15%), bla(CTX-M-14) (n = 15, 5%), bla(SHV-12) (n = 24, 8%) and bla(TEM-52) (n = 13, 4%). Among 181 isolates with MIC ≥16 mg/L for cefoxitin plasmid encoded AmpCs were detected in 32 and 27 were of the CMY-2 group. Among 102 E. coli isolates with MIC ≥16 mg/L for cefoxitin ampC promoter mutations were identified in 29 (28%). Based on Diversilab genotyping of 608 isolates (similarity cut-off >98%) discriminatory indices of bacteria with ESBL and/or ampC genes were 0.994, 0.985 and 0.994 for E. coli, K. pneumoniae and E. cloacae, respectively. Based on similarity cut-off >95% two large clusters of E. coli were apparent (of 43 and 30 isolates) and 21 of 21 that were typed by belonged to ST131 of which 13 contained bla(CTX-M-15). Our findings demonstrate that bla(CTX-M-15) is the most prevalent ESBL and we report a larger than previously reported prevalence of ampC genes among Enterobacteriaceae responsible for resistance to third-generation cephalosporins.

  6. Effect of Distributed Photovoltaic Generation on the Voltage Magnitude in a Self-Contained Power Supply System

    NASA Astrophysics Data System (ADS)

    Lukutin, B. V.; Shandarova, E. B.; Makarova, A. F.; Shvartsman, I. B.

    2016-04-01

    A promising way to increase the technical and economic characteristics of standalone power supply systems is to incorporate renewable energy installations in their structure. This saves fuel and extends the operational life of diesel power stations. The most common option is a hybrid system with photovoltaic power stations incorporated into the local network of the diesel power station. This paper deals with the dependence of the deflection voltage and power losses in the electric power transmission line on the graphs of electrical loads, the parameters of elements of the power supply system, connection points and the capacity of distributed photovoltaic power stations. Research has been carried out on the common low-voltage power supply systems of the radial type (0.4 kV) with an installed capacity of up to 100 kW. The studies have been conducted by simulating the operating modes of hybrid power systems of various configurations. As a result of these studies recommendations to reduce losses and voltage variations in the network by selecting the power and photovoltaic power connection points have been put forward.

  7. Economic feasibility analysis of distributed electric power generation based upon the natural gas-fired fuel cell. Final report

    SciTech Connect

    Not Available

    1994-03-01

    The final report provides a summary of results of the Cost of Ownership Model and the circumstances under which a distributed fuel cell is economically viable. The analysis is based on a series of micro computer models estimate the capital and operations cost of a fuel cell central utility plant configuration. Using a survey of thermal and electrical demand profiles, the study defines a series of energy user classes. The energy user class demand requirements are entered into the central utility plant model to define the required size the fuel cell capacity and all supporting equipment. The central plant model includes provisions that enables the analyst to select optional plant features that are most appropriate to a fuel cell application, and that are cost effective. The model permits the choice of system features that would be suitable for a large condominium complex or a residential institution such as a hotel, boarding school or prison. Other applications are also practical; however, such applications have a higher relative demand for thermal energy, a characteristic that is well-suited to a fuel cell application with its free source of hot water or steam. The analysis combines the capital and operation from the preceding models into a Cost of Ownership Model to compute the plant capital and operating costs as a function of capacity and principal features and compares these estimates to the estimated operating cost of the same central plant configuration without a fuel cell.

  8. Economic feasibility analysis of distributed electric power generation based upon the natural gas-fired fuel cell

    NASA Astrophysics Data System (ADS)

    1994-03-01

    The final report provides a summary of results of the Cost of Ownership Model and the circumstances under which a distributed fuel cell is economically viable. The analysis is based on a series of micro computer models estimates of the capital and operations cost of a fuel cell central utility plant configuration. Using a survey of thermal and electrical demand profiles, the study defines a series of energy user classes. The energy user class demand requirements are entered into the central utility plant model to define the required size the fuel cell capacity and all supporting equipment. The central plant model includes provisions that enables the analyst to select optional plant features that are most appropriate to a fuel cell application, and that are cost effective. The model permits the choice of system features that would be suitable for a large condominium complex or a residential institution such as a hotel, boarding school or prison. Other applications are also practical; however, such applications have a higher relative demand for thermal energy, a characteristic that is well-suited to a fuel cell application with its free source of hot water or steam. The analysis combines the capital and operation from the preceding models into a Cost of Ownership Model to compute the plant capital and operating costs as a function of capacity and principal features and compares these estimates to the estimated operating cost of the same central plant configuration without a fuel cell.

  9. Methods for Analyzing the Benefits and Costs of Distributed Photovoltaic Generation to the U.S. Electric Utility System

    SciTech Connect

    Denholm, P.; Margolis, R.; Palmintier, B.; Barrows, C.; Ibanez, E.; Bird, L.; Zuboy, J.

    2014-09-01

    This report outlines the methods, data, and tools that could be used at different levels of sophistication and effort to estimate the benefits and costs of DGPV. In so doing, we identify the gaps in current benefit-cost-analysis methods, which we hope will inform the ongoing research agenda in this area. The focus of this report is primarily on benefits and costs from the utility or electricity generation system perspective. It is intended to provide useful background information to utility and regulatory decision makers and their staff, who are often being asked to use or evaluate estimates of the benefits and cost of DGPV in regulatory proceedings. Understanding the technical rigor of the range of methods and how they might need to evolve as DGPV becomes a more significant contributor of energy to the electricity system will help them be better consumers of this type of information. This report is also intended to provide information to utilities, policy makers, PV technology developers, and other stakeholders, which might help them maximize the benefits and minimize the costs of integrating DGPV into a changing electricity system.

  10. INFLUENCE OF ELECTRON-IMPACT MULTIPLE IONIZATION ON EQUILIBRIUM AND DYNAMIC CHARGE STATE DISTRIBUTIONS: A CASE STUDY USING IRON

    SciTech Connect

    Hahn, M.; Savin, D. W.

    2015-02-10

    We describe the influence of electron-impact multiple ionization (EIMI) on the ionization balance of collisionally ionized plasmas. Previous ionization balance calculations have largely neglected EIMI. Here, EIMI cross-section data are incorporated into calculations of both equilibrium and non-equilibrium charge-state distributions (CSDs). For equilibrium CSDs, we find that EIMI has only a small effect and can usually be ignored. However, for non-equilibrium plasmas the influence of EIMI can be important. In particular, we find that for plasmas in which the temperature oscillates there are significant differences in the CSD when including versus neglecting EIMI. These results have implications for modeling and spectroscopy of impulsively heated plasmas, such as nanoflare heating of the solar corona.

  11. Colloidal mercury (Hg) distribution in soil samples by sedimentation field-flow fractionation coupled to mercury cold vapour generation atomic absorption spectroscopy.

    PubMed

    Santoro, A; Terzano, R; Medici, L; Beciani, M; Pagnoni, A; Blo, G

    2012-01-01

    Diverse analytical techniques are available to determine the particle size distribution of potentially toxic elements in matrices of environmental interest such as soil, sediments, freshwater and groundwater. However, a single technique is often not exhaustive enough to determine both particle size distribution and element concentration. In the present work, the investigation of mercury in soil samples collected from a polluted industrial site was performed by using a new analytical approach which makes use of sedimentation field-flow fractionation (SdFFF) coupled to cold vapour generation electrothermal atomic absorption spectroscopy (CV-ETAAS). The Hg concentration in the SdFFF fractions revealed a broad distribution from about 0.1 to 1 μm, roughly following the particle size distributions, presenting a maximum at about 400-700 nm in diameter. A correlation between the concentration of Hg in the colloidal fraction and organic matter (O.M.) content in the soil samples was also found. However, this correlation is less likely to be related to Hg sorption to soil O.M. but rather to the presence of colloidal mercuric sulfide particles whose size is probably controlled by the occurrence of dissolved O.M. The presence of O.M. could have prevented the aggregation of smaller particles, leading to an accumulation of mercuric sulfides in the colloidal fraction. In this respect, particle size distribution of soil samples can help to understand the role played by colloidal particles in mobilising mercury (also as insoluble compounds) and provide a significant contribution in determining the environmental impact of this toxic element.

  12. Microfluidics and Stimulus-Responsive Materials -- The Key to Next Generation Chemical Sensors for Widely Distributed Environmental Monitoring

    NASA Astrophysics Data System (ADS)

    Diamond, Dermot

    2012-02-01

    The fields of chemical sensing and microfluidics have promised much, but in terms of functional devices, have delivered relatively little. Issues like biofouling and surface degradation mean that sensor characteristics change rapidly in real samples. Consequently, chemical sensors must be regularly recalibrated to ensure the information they send is reliable. This results in complex and very costly devices that must integrate fluidics, standards, and waste storage, as well as sampling and analytical procedures. The fundamental challenge for realizing sensors for widely distributed environmental monitoring is this - how can we produce low cost sensing platforms that can function reliably in an autonomous manner for periods up to years? The key to progress lies in new, and more sophisticated materials that can respond to external stimuli, and communicate with the external world. For example, materials that can be activated from a passive state, reversibly bind and release targeted guest molecules, and return to a passive form. Activation and deactivation happen as part of an external control system, which can be local (chemical in nature) or external (e.g. photonic), and the material reports its status (passive, activated-free, activated-occupied) optically materials can be incorporated into more sophisticated platforms, such as micelles, beads, or complete fluidic systems that are much more biomimetic in nature than current platforms. They include polymer actuators that expand and contract dramatically under an external stimulus (e.g. light), enabling valve and pumping functions to be fully integrated into the microfluidic device. This lecture, I will present some of the exciting possibilities for chemical sensing that are now beginning to emerge through breakthroughs in fundamental materials science.

  13. Comparison of projection skills of deterministic ensemble methods using pseudo-simulation data generated from multivariate Gaussian distribution

    NASA Astrophysics Data System (ADS)

    Oh, Seok-Geun; Suh, Myoung-Seok

    2016-03-01

    The projection skills of five ensemble methods were analyzed according to simulation skills, training period, and ensemble members, using 198 sets of pseudo-simulation data (PSD) produced by random number generation assuming the simulated temperature of regional climate models. The PSD sets were classified into 18 categories according to the relative magnitude of bias, variance ratio, and correlation coefficient, where each category had 11 sets (including 1 truth set) with 50 samples. The ensemble methods used were as follows: equal weighted averaging without bias correction (EWA_NBC), EWA with bias correction (EWA_WBC), weighted ensemble averaging based on root mean square errors and correlation (WEA_RAC), WEA based on the Taylor score (WEA_Tay), and multivariate linear regression (Mul_Reg). The projection skills of the ensemble methods improved generally as compared with the best member for each category. However, their projection skills are significantly affected by the simulation skills of the ensemble member. The weighted ensemble methods showed better projection skills than non-weighted methods, in particular, for the PSD categories having systematic biases and various correlation coefficients. The EWA_NBC showed considerably lower projection skills than the other methods, in particular, for the PSD categories with systematic biases. Although Mul_Reg showed relatively good skills, it showed strong sensitivity to the PSD categories, training periods, and number of members. On the other hand, the WEA_Tay and WEA_RAC showed relatively superior skills in both the accuracy and reliability for all the sensitivity experiments. This indicates that WEA_Tay and WEA_RAC are applicable even for simulation data with systematic biases, a short training period, and a small number of ensemble members.

  14. Efficient generation of cylindrically polarized beams in an Yb:YAG thin-disk laser enabled by a ring-shaped pumping distribution

    NASA Astrophysics Data System (ADS)

    Dietrich, Tom; Rumpel, Martin; Graf, Thomas; Abdou Ahmed, Marwan

    2016-04-01

    The efficient generation of a cylindrically (radially or azimuthally) polarized LG01 mode was investigated using a ring-shaped pumping distribution in a high-power Yb:YAG thin-disk laser setup. This was realized by implementing a 300 mm long customized fused silica fiber capillary in the pump beam path of the pumping optics of a thin-disk laser. Furthermore, a grating waveguide mirror based on the leaky-mode coupling mechanism was used as one of the cavity end mirrors to allow sufficient reduction of the reflectivity of the polarization state to be suppressed in the resonator. In order to achieve efficient laser operation, an optimized mode overlap between the ring-shaped pump spot and the excited first order Laguerre-Gaussian doughnut mode is required. This was investigated theoretically by analyzing the intensity distribution generated by different fiber geometries using a commercially raytracing software (Zemax). The output power, polarization state and efficiency of the emitted laser beam were compared to that obtained with a standard flattop pumping distribution. In particular, the thermal behavior of the disk was investigated since the excessive fluorescence caused by the non-saturated excitation in the center of the homogeneously pumped disk leads to a strong heating of the crystal. This considerable heating source is avoided in the case of the ring-shaped pumping and a reduction of the temperature increase on the disk surface of about 21% (at 280 W of pump power) was observed. This should allow higher pump power densities without increasing the risk of damaging the disk or distorting the polarization purity. With a laser efficiency of 41.2% to be as high as in the case of the flattop pumping, a maximum output power of 107 W was measured.

  15. The Effects of Realistic Synaptic Distribution and 3D Geometry on Signal Integration and Extracellular Field Generation of Hippocampal Pyramidal Cells and Inhibitory Neurons

    PubMed Central

    Gulyás, Attila I.; Freund, Tamás F.; Káli, Szabolcs

    2016-01-01

    In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In

  16. The Effects of Realistic Synaptic Distribution and 3D Geometry on Signal Integration and Extracellular Field Generation of Hippocampal Pyramidal Cells and Inhibitory Neurons.

    PubMed

    Gulyás, Attila I; Freund, Tamás F; Káli, Szabolcs

    2016-01-01

    In vivo and in vitro multichannel field and somatic intracellular recordings are frequently used to study mechanisms of network pattern generation. When interpreting these data, neurons are often implicitly considered as electrotonically compact cylinders with a homogeneous distribution of excitatory and inhibitory inputs. However, the actual distributions of dendritic length, diameter, and the densities of excitatory and inhibitory input are non-uniform and cell type-specific. We first review quantitative data on the dendritic structure and synaptic input and output distribution of pyramidal cells (PCs) and interneurons in the hippocampal CA1 area. Second, using multicompartmental passive models of four different types of neurons, we quantitatively explore the effect of differences in dendritic structure and synaptic distribution on the errors and biases of voltage clamp measurements of inhibitory and excitatory postsynaptic currents. Finally, using the 3-dimensional distribution of dendrites and synaptic inputs we calculate how different inhibitory and excitatory inputs contribute to the generation of local field potential in the hippocampus. We analyze these effects at different realistic background activity levels as synaptic bombardment influences neuronal conductance and thus the propagation of signals in the dendritic tree. We conclude that, since dendrites are electrotonically long and entangled in 3D, somatic intracellular and field potential recordings miss the majority of dendritic events in some cell types, and thus overemphasize the importance of perisomatic inhibitory inputs and belittle the importance of complex dendritic processing. Modeling results also suggest that PCs and inhibitory neurons probably use different input integration strategies. In PCs, second- and higher-order thin dendrites are relatively well-isolated from each other, which may support branch-specific local processing as suggested by studies of active dendritic integration. In

  17. Angular and internal state distributions of H2+ generated by (2 + 1) resonance enhanced multiphoton ionization of H2 using time-of-flight mass spectrometry

    NASA Astrophysics Data System (ADS)

    Perreault, William E.; Mukherjee, Nandini; Zare, Richard N.

    2016-06-01

    We report direct measurement of the anisotropy parameter β for the angular distribution of the photoelectron and photoion in (2 + 1) resonance enhanced multiphoton ionization process of H2 X 1 Σg + (v = 0, J = 0) molecules through the intermediate H2 E,F 1 Σg + (v' = 0, J' = 0) level (λ = 201.684 nm) using a time-of-flight mass spectrometer. The time-of-flight spectra were recorded as the direction of polarization of the ionizing laser was varied with respect to the flight axis of the H2 molecular beam and were fitted to an angular distribution in an appropriately rotated coordinate system with the z-axis oriented along the time-of-flight axis. The anisotropy parameter β was found to be 1.72 ± 0.13 by fitting the time-of-flight spectra and agreed with previous measurements. Using secondary ionization with a delayed laser pulse of different wavelength, we also determined the vibrational energy distribution of the ions, showing that 98% ± 4% of the ions are generated in their ground vibrational state, in agreement with the calculated Franck-Condon factors between the H2 E,F 1 Σg + (v' = 0) and H 2+ X 1 Σg + (v″) vibrational levels.

  18. Understanding the design and economics of distributed tri-generation systems for home and neighborhood refueling-Part II: Neighborhood system case studies

    NASA Astrophysics Data System (ADS)

    Li, Xuping; Ogden, Joan M.

    2012-01-01

    The lack of a hydrogen infrastructure remains a major barrier for fuel cell vehicle (FCV) adoption. The high cost of an extensive hydrogen station network and the low utilization in the near term discourage private investment. Past experience of fuel infrastructure development for motor vehicles, indicates that innovative, distributed, small-volume hydrogen refueling methods may be required to refuel FCVs in the near term. Among small-volume refueling methods, home and neighborhood tri-generation systems stand out because the technology is available and has potential to alleviate consumer's fuel availability concerns. Additionally, it has features attractive to consumers such as convenience and security to refuel at home or in their neighborhood. In this paper, we study neighborhood tri-generation systems in multi-unit dwellings such as apartment complexes. We apply analytical tools including an interdisciplinary framework and an engineering/economic model to a representative multi-family residence in the Northern California area. The simulation results indicate that a neighborhood tri-generation system improves the economics of providing the three energy products for the households compared with the two alternatives studied. The small capacity of the systems and the valuable co-products help address the low utilization problem of hydrogen infrastructure.

  19. Next-Generation Angular Distribution Models for Top-of-Atmosphere Radiative Flux Calculation from CERES Instruments: Validation

    NASA Technical Reports Server (NTRS)

    Su, W.; Corbett, J.; Eitzen, Z.; Liang, L.

    2015-01-01

    Radiative fluxes at the top of the atmosphere (TOA) from the Clouds and the Earth's Radiant Energy System (CERES) instrument are fundamental variables for understanding the Earth's energy balance and how it changes with time. TOA radiative fluxes are derived from the CERES radiance measurements using empirical angular distribution models (ADMs). This paper evaluates the accuracy of CERES TOA fluxes using direct integration and flux consistency tests. Direct integration tests show that the overall bias in regional monthly mean TOA shortwave (SW) flux is less than 0.2Wm(exp -2) and the RMSE is less than 1.1Wm(exp -2). The bias and RMSE are very similar between Terra and Aqua. The bias in regional monthly mean TOA LW fluxes is less than 0.5Wm(exp -2) and the RMSE is less than 0.8Wm(exp -)2 for both Terra and Aqua. The accuracy of the TOA instantaneous flux is assessed by performing tests using fluxes inverted from nadir- and oblique-viewing angles using CERES along-track observations and temporally and spatially matched MODIS observations, and using fluxes inverted from multi-angle MISR observations. The averaged TOA instantaneous SW flux uncertainties from these two tests are about 2.3% (1.9Wm(exp -2) over clear ocean, 1.6% (4.5Wm(exp -2) over clear land, and 2.0% (6.0Wm(exp -) over clear snow/ice; and are about 3.3% (9.0Wm(exp -2), 2.7% (8.4Wm(exp -2), and 3.7% (9.9Wm(exp -2) over ocean, land, and snow/ice under all-sky conditions. The TOA SW flux uncertainties are generally larger for thin broken clouds than for moderate and thick overcast clouds. The TOA instantaneous daytime LW flux uncertainties derived from the CERESMODIS test are 0.5% (1.5Wm(exp -2), 0.8% (2.4Wm(exp -2), and 0.7% (1.3Wm(exp -2) over clear ocean, land, and snow/ice; and are about 1.5% (3.5Wm(exp -2), 1.0% (2.9Wm(exp -2), and 1.1% (2.1Wm(exp -2) over ocean, land, and snow/ice under all-sky conditions. The TOA instantaneous nighttime LW flux uncertainties are about 0.5-1% (<2.0Wm(exp -2) for all

  20. Effects of the large distribution of CdS quantum dot sizes on the charge transfer interactions into TiO2 nanotubes for photocatalytic hydrogen generation.

    PubMed

    González-Moya, Johan R; Garcia-Basabe, Yunier; Rocco, Maria Luiza M; Pereira, Marcelo B; Princival, Jefferson L; Almeida, Luciano C; Araújo, Carlos M; David, Denis G F; da Silva, Antonio Ferreira; Machado, Giovanna

    2016-07-15

    Hydrogen fuels generated by water splitting using a photocatalyst and solar irradiation are currently gaining the strength to diversify the world energy matrix in a green way. CdS quantum dots have revealed a hydrogen generation improvement when added to TiO2 materials under visible-light irradiation. In the present paper, we investigated the performance of TiO2 nanotubes coupled with CdS quantum dots, by a molecular bifunctional linker, on photocatalytic hydrogen generation. TiO2 nanotubes were obtained by anodization of Ti foil, followed by annealing to crystallize the nanotubes into the anatase phase. Afterwards, the samples were sensitized with CdS quantum dots via an in situ hydrothermal route using 3-mercaptopropionic acid as the capping agent. This sensitization technique permits high loading and uniform distribution of CdS quantum dots onto TiO2 nanotubes. The XPS depth profile showed that CdS concentration remains almost unchanged (homogeneous), while the concentration relative to the sulfate anion decreases by more than 80% with respect to the initial value after ∼100 nm in depth. The presence of sulfate anions is due to the oxidation of sulfide and occurs in greater proportion in the material surface. This protection for air oxidation inside the nanotubular matrix seemingly protected the CdS for photocorrosion in sacrificial solution leading to good stability properties proved by long duration, stable photocurrent measurements. The effect of the size and the distribution of sizes of CdS quantum dots attached to TiO2 nanotubes on the photocatalytic hydrogen generation were investigated. The experimental results showed three different behaviors when the reaction time of CdS synthesis was increased in the sensitized samples, i.e. similar, deactivation and activation effects on the hydrogen production with regard to TiO2 nanotubes. The deactivation effect was related to two populations of sizes of CdS, where the population with a shorter band gap acts as a

  1. Effects of the large distribution of CdS quantum dot sizes on the charge transfer interactions into TiO2 nanotubes for photocatalytic hydrogen generation

    NASA Astrophysics Data System (ADS)

    González-Moya, Johan R.; Garcia-Basabe, Yunier; Rocco, Maria Luiza M.; Pereira, Marcelo B.; Princival, Jefferson L.; Almeida, Luciano C.; Araújo, Carlos M.; David, Denis G. F.; Ferreira da Silva, Antonio; Machado, Giovanna

    2016-07-01

    Hydrogen fuels generated by water splitting using a photocatalyst and solar irradiation are currently gaining the strength to diversify the world energy matrix in a green way. CdS quantum dots have revealed a hydrogen generation improvement when added to TiO2 materials under visible-light irradiation. In the present paper, we investigated the performance of TiO2 nanotubes coupled with CdS quantum dots, by a molecular bifunctional linker, on photocatalytic hydrogen generation. TiO2 nanotubes were obtained by anodization of Ti foil, followed by annealing to crystallize the nanotubes into the anatase phase. Afterwards, the samples were sensitized with CdS quantum dots via an in situ hydrothermal route using 3-mercaptopropionic acid as the capping agent. This sensitization technique permits high loading and uniform distribution of CdS quantum dots onto TiO2 nanotubes. The XPS depth profile showed that CdS concentration remains almost unchanged (homogeneous), while the concentration relative to the sulfate anion decreases by more than 80% with respect to the initial value after ˜100 nm in depth. The presence of sulfate anions is due to the oxidation of sulfide and occurs in greater proportion in the material surface. This protection for air oxidation inside the nanotubular matrix seemingly protected the CdS for photocorrosion in sacrificial solution leading to good stability properties proved by long duration, stable photocurrent measurements. The effect of the size and the distribution of sizes of CdS quantum dots attached to TiO2 nanotubes on the photocatalytic hydrogen generation were investigated. The experimental results showed three different behaviors when the reaction time of CdS synthesis was increased in the sensitized samples, i.e. similar, deactivation and activation effects on the hydrogen production with regard to TiO2 nanotubes. The deactivation effect was related to two populations of sizes of CdS, where the population with a shorter band gap acts as a

  2. Dynamics of short-pulse generation via spectral filtering from intensely excited gain-switched 1.55-μm distributed-feedback laser diodes.

    PubMed

    Chen, Shaoqiang; Yoshita, Masahiro; Sato, Aya; Ito, Takashi; Akiyama, Hidefumi; Yokoyama, Hiroyuki

    2013-05-06

    Picosecond-pulse-generation dynamics and pulse-width limiting factors via spectral filtering from intensely pulse-excited gain-switched 1.55-μm distributed-feedback laser diodes were studied. The spectral and temporal characteristics of the spectrally filtered pulses indicated that the short-wavelength component stems from the initial part of the gain-switched main pulse and has a nearly linear down-chirp of 5.2 ps/nm, whereas long-wavelength components include chirped pulse-lasing components and steady-state-lasing components. Rate-equation calculations with a model of linear change in refractive index with carrier density explained the major features of the experimental results. The analysis of the expected pulse widths with optimum spectral widths was also consistent with the experimental data.

  3. Efficient generation of 1.9  W yellow light by cascaded frequency doubling of a distributed Bragg reflector tapered diode.

    PubMed

    Hansen, A K; Christensen, M; Noordegraaf, D; Heist, P; Papastathopoulos, E; Loyo-Maldonado, V; Jensen, O B; Skovgaard, P M W

    2016-11-10

    Watt-level yellow emitting lasers are interesting for medical applications, due to their high hemoglobin absorption, and for efficient detection of certain fluorophores. In this paper, we demonstrate a compact and robust diode-based laser system in the yellow spectral range. The system generates 1.9 W of single-frequency light at 562.4 nm by cascaded single-pass frequency doubling of the 1124.8 nm emission from a distributed Bragg reflector (DBR) tapered laser diode. The absence of a free-space cavity makes the system stable over a base-plate temperature range of 30 K. At the same time, the use of a laser diode enables the modulation of the pump wavelength by controlling the drive current. This is utilized to achieve a power modulation depth above 90% for the second harmonic light, with a rise time below 40  μs.

  4. An approach for generating trajectory-based dynamics which conserves the canonical distribution in the phase space formulation of quantum mechanics. I. Theories.

    PubMed

    Liu, Jian; Miller, William H

    2011-03-14

    We have reformulated and generalized our recent work [J. Liu and W. H. Miller, J. Chem. Phys. 126, 234110 (2007)] into an approach for generating a family of trajectory-based dynamics methods in the phase space formulation of quantum mechanics. The approach (equilibrium Liouville dynamics) is in the spirit of Liouville's theorem in classical mechanics. The trajectory-based dynamics is able to conserve the quantum canonical distribution for the thermal equilibrium system and approaches classical dynamics in the classical (ℏ → 0), high temperature (β → 0), and harmonic limits. Equilibrium Liouville dynamics provides the framework for the development of novel theoretical∕computational tools for studying quantum dynamical effects in large∕complex molecular systems.

  5. An approach for generating trajectory-based dynamics which conserves the canonical distribution in the phase space formulation of quantum mechanics. I. Theories

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Miller, William H.

    2011-03-01

    We have reformulated and generalized our recent work [J. Liu and W. H. Miller, J. Chem. Phys. 126, 234110 (2007)] into an approach for generating a family of trajectory-based dynamics methods in the phase space formulation of quantum mechanics. The approach (equilibrium Liouville dynamics) is in the spirit of Liouville's theorem in classical mechanics. The trajectory-based dynamics is able to conserve the quantum canonical distribution for the thermal equilibrium system and approaches classical dynamics in the classical (ℏ → 0), high temperature (β → 0), and harmonic limits. Equilibrium Liouville dynamics provides the framework for the development of novel theoretical/computational tools for studying quantum dynamical effects in large/complex molecular systems.

  6. Population pharmacokinetics, brain distribution, and pharmacodynamics of 2nd generation dopamine transporter selective benztropine analogs developed as potential substitute therapeutics for treatment of cocaine abuse.

    PubMed

    Syed, Shariq A; Newman, Amy H; Othman, Ahmed A; Eddington, Natalie D

    2008-05-01

    A second generation of N-substituted 3alpha-[bis(4'-fluorophenyl)methoxy]-tropanes (GA 1-69, JHW 005 and JHW 013) binds with high affinity to the dopamine transporter (DAT) and are highly selective toward DAT compared to muscarinic receptor binding (M1). The objective of this study was to characterize brain distribution, pharmacokinetics, and pharmacodynamics [extracellular brain dopamine (DA) levels] of three novel N-substituted benztropine (BZT) analogs in male Sprague-Dawley rats. The BZT analogs displayed a higher distribution (Vd = 8.69-34.3 vs. 0.9 L/kg) along with longer elimination (t l/2: 4.1-5.4 vs. 0.5 h) than previously reported for cocaine. Brain-to-plasma partition coefficients were 1.3-2.5 vs. 2.1 for cocaine. The effect of the BZT analogs on extracellular brain (DA) levels ranged from minimal effects (GA 1-69) to several fold elevation (approximately 850% of basal DA for JHW 013) at the highest dose evaluated. PK/PD analysis of exposure-response data resulted in lower IC50 values for the BZT analogs compared to cocaine indicating their higher potency to inhibit DA reuptake (0.1-0.3 vs. 0.7 mg/L). These BZT analogs possess significantly different PK and PD profiles as compared to cocaine suggesting that further evaluation as cocaine abuse therapeutics is warranted.

  7. Air quality impacts of distributed power generation in the South Coast Air Basin of California 1: Scenario development and modeling analysis

    NASA Astrophysics Data System (ADS)

    Rodriguez, M. A.; Carreras-Sospedra, M.; Medrano, M.; Brouwer, J.; Samuelsen, G. S.; Dabdub, D.

    Distributed generation (DG) is generally defined as the operation of many small stationary power generators throughout an urban air basin. Although DG has the potential to supply a significant portion of the increased power demands in California and the rest of the United States, it may lead to increased levels of in-basin pollutants and adversely impact urban air quality. This study focuses on two main objectives: (1) the systematic characterization of DG installation in urban air basins, and (2) the simulation of potential air quality impacts using a state-of-the-art three-dimensional computational model. A general and systematic approach is devised to construct five realistic and 21 spanning scenarios of DG implementation in the South Coast Air Basin (SoCAB) of California. Realistic scenarios reflect an anticipated level of DG deployment in the SoCAB by the year 2010. Spanning scenarios are developed to determine the potential impacts of unexpected outcomes. Realistic implementations of DG in the SoCAB result in small differences in ozone and particulate matter concentrations in the basin compared to the baseline simulations. The baseline accounts for population increase, but does not consider any future emissions control measures. Model results for spanning implementations with extra high DG market penetration show that domain-wide ozone peak concentrations increase significantly. Also, air quality impacts of spanning implementations when DG operate during a 6-h period are larger than when the same amount of emissions are introduced during a 24-h period.

  8. The spatial distribution in high-order harmonic generation of H2+ with different time delays of the two-color laser fields

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Pan, Xue-Fei; Du, Hui; Xu, Tong-Tong; Guo, Jing; Liu, Xue-Shen

    2017-01-01

    We theoretically investigate the high-order harmonic generation (HHG) and the spatial distribution in HHG of the H2+ molecule by introducing a time-delayed two-color laser field which consists of the mid-infrared and near-infrared laser field. For the different time delays of the two-color laser fields, the pulse shapes are changed which result in the variation of the electron recombined with the nuclei along the positive- or negative-z direction. When the time delay is 0 fs (1.34 fs), a smooth harmonic plateau from the electron recombined with the nuclei along the negative (positive)-z direction can be achieved. An isolated attosecond pulse with a duration of about 99 as is generated when the time delay is 1.34 fs. We perform the classical analysis which is consistent with the numerical results from the one-dimensional non-Born-Oppenheimer time dependent Schrödinger equation (TDSE). We also investigate emission time of harmonics in terms of a time-frequency analysis to further understand the underlying physical mechanism.

  9. Independent Orbiter Assessment (IOA): Assessment of the Electrical Power Distribution and Control/Electrical Power Generation (EPD and C/EPG) FMEA/CIL

    NASA Technical Reports Server (NTRS)

    Mccants, C. N.; Bearrow, M.

    1988-01-01

    The results of the Independent Orbiter Assessment (IOA) of the Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL) are presented. The IOA effort first completed an analysis of the Electrical Power Distribution and Control/Electrical Power Generation (EPD and C/EPG) hardware, generating draft failure modes and potential critical items. To preserve independence, this analysis was accomplished without reliance upon the results contained within the NASA FMEA/CIL documentation. The IOA results were then compared to the NASA FMEA/CIL baseline with proposed Post 51-L updates included. A resolution of each discrepancy from the comparison was provided through additional analysis as required. The results of that comparison is documented for the Orbiter EPD and C/EPG hardware. The IOA product for the EPD and C/EPG analysis consisted of 263 failure mode worksheets that resulted in 42 potential critical items being identified. Comparison was made to the NASA baseline which consisted of 211 FMEA and 47 CIL items.

  10. The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (Japanese translation)

    SciTech Connect

    Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun; Nishida, Masaru

    2004-10-15

    The August 2003 blackout of the northeastern U.S. and CANADA caused great economic losses and inconvenience to New York City and other affected areas. The blackout was a warning to the rest of the world that the ability of conventional power systems to meet growing electricity demand is questionable. Failure of large power systems can lead to serious emergencies. Introduction of on-site generation, renewable energy such as solar and wind power and the effective utilization of exhaust heat is needed, to meet the growing energy demands of the residential and commercial sectors. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems. This work demonstrates a method for choosing and designing economically optimal DER systems. An additional purpose of this research is to establish a database of energy tariffs, DER technology cost and performance characteristics, and building energy consumption for Japan. This research builds on prior DER studies at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) and with their associates in the Consortium for Electric Reliability Technology Solutions (CERTS) and operation, including the development of the microgrid concept, and the DER selection optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM is a tool designed to find the optimal combination of installed equipment and an idealized operating schedule to minimize a site's energy bills, given performance and cost data on available DER technologies, utility tariffs, and site electrical and thermal loads over a test period, usually an historic year. Since hourly electric and thermal energy data are rarely available, they are typically developed by building simulation for each of six end use loads used to model the building: electric-only loads, space heating, space cooling, refrigeration, water heating, and natural-gas-only loads. DER-CAM provides a

  11. Next Generation Distributed Sensor Networks

    DTIC Science & Technology

    2004-09-01

    the exciting information processing problems that are being solved to effectively harvest the benefits of current and emerging nano , micro ...A number of nano and micro sensors are being introduced each month ranging from biological sensors to complex RF and optical sensors. The mass...sensor networks as one of the top ten emerging technologies. The July 2003 issue of the IEEE Proceeding is devoted to micro and nano sensors

  12. Effects on aerosol size distribution of polycyclic aromatic hydrocarbons from the heavy-duty diesel generator fueled with feedstock palm-biodiesel blends

    NASA Astrophysics Data System (ADS)

    Lin, Yuan-Chung; Tsai, Cheng-Hsien; Yang, Chi-Ru; Wu, C. H. Jim; Wu, Tzi-Yi; Chang-Chien, Guo-Ping

    Biodiesels are promoted as alternatives to fossil fuels and their applications in diesel engine have been studied extensively. However, the size distribution of polycyclic aromatic hydrocarbons (PAHs) and generator particulate material (GPM) emitted from heavy-duty diesel generator fueled with biodiesel blends has seldom been addressed. Seven different biodiesel blends with volume fractions of biodiesel ranging from 0% to 30% were studied. Experimental results indicate that the mean reductions of sum of PAHi/GPM 0.056-18 (generator particulate material with aerodynamic diameter 0.056-18 μm) and BaP eqi [=(benzo[ a]pyrene equivalent)i]/GPM 0.056-18 of B5, B10, B15, B20, B25 and B30 are (-8.21%, -5.72%), (-36.7%, -29.7%), (-1.25%, 2.32%), (16.2%, 18.6%), (33.4%, 35.0%) and (40.5%, 42.4), respectively, compared with B0. Both PAHi/GPMi and BaP eqi/GPMi in stage 1 (0.056 - 0.166 μm) and stage 2 (0.166 - 0.31 μm) of all test fuels are higher than those in the other stages due to higher specific surface area of smaller particles. It is also observed that there are more highly toxic PAHs in stage 2. It should be noticed that the trend of particle-phase PAH contents is different from the trend of particle-phase PAH concentration and opposite to the trend of total GPM 0.056-18 emission. The differences are due to a higher number of particles with diameters between 0.056 and 0.31 μm. The above results indicate that fuel blends with less than 15% biodiesel would increase PAH content at particle size between 0.056 and 0.31 μm. Therefore, the blending fraction should be between 15% and 30%. Moreover, particle-size control is needed in future emission regulations which would necessitate further improvements in combustion quality. Besides, researches on health effects of biodiesel blends are needed as well.

  13. Multi-purpose droop controllers incorporating a passivity-based stabilizer for unified control of electronically interfaced distributed generators including primary source dynamics.

    PubMed

    Azimi, Seyed Mohammad; Afsharnia, Saeed

    2016-07-01

    This paper presents multi-purpose droop controllers for electronically-interfaced distributed generators (EI-DGs). These controllers allow the micro-grids to operate in grid-connected mode, islanded mode and mode transition transients with a unique control configuration. The active and reactive-power sharing among EI-DGs are satisfied by the proposed droop controllers in islanded mode. On the other hand, in the grid-connected mode, the droop controllers adjust the output active and reactive-powers of EI-DGs at the pre-programmed constant levels. The provision of sufficient damping capability and maintenance of the transient stability in all operational modes of EI-DGs are warranted by the suggested stabilizer. This stabilizer, which is designed using the passivity-based control (PBC) approach, is incorporated in the droop controllers to dampen power-angle, frequency and voltage deviations during large transients using solely local information. The primary source dynamics of EI-DGs are also considered. It is analytically proven that the presence of the primary source dynamics leads to attenuation of the damping capability of EI-DGs in transients. To compensate the adverse effect of the primary source dynamics during transients a novel compensator is inserted in the frequency-droop loop. Finally, time-domain simulations are performed on a multi-resources MG to verify the analytical results compared to those obtained, based on a recently-developed strategy.

  14. Immobilization of nanobeads on a surface to control the size, shape and distribution of pores in electrochemically generated sol-gel films

    PubMed Central

    Ciabocco, Michela; Berrettoni, Mario; Zamponi, Silvia

    2015-01-01

    Electrochemically assisted deposition of an ormosil film at a potential where hydrogen ion is generated as the catalyst yields insulating films on electrodes. When the base electrode is modified with 20-nm poly(styrene sulfonate), PSS, beads bound to the surface with 3-aminopropyltriethoxysilane (APTES) and using (CH3)3SiOCH3 as the precursor, the resulting film of organically modified silica (ormosil) has cylindrical channels that reflect both the diameter of the PSS and the distribution of the APTES-PSS on the electrode. At an electrode modified by a 20-min immersion in 0.5 mmol dm-3 APTES followed by a 30-s immersion in PSS, a 20-min electrolysis at 1.5 V in acidified (CH3)3SiOCH3 resulted in an ormosil film with 20-nm pores separated by 100 nm. Cyclic voltammetry of Ru(CN)64- at scan rates above 5 mVs-1 yielded currents controlled primarily by linear diffusion. Below 5 mVs-1, convection rather than the expected factor, radial diffusion, apparently limited the current. PMID:26167128

  15. Asymmetries in coronal spectral lines and emission measure distribution

    SciTech Connect

    Tripathi, Durgesh; Klimchuk, James A.

    2013-12-10

    It has previously been argued that (1) spicules do not provide enough pre-heated plasma to fill the corona, and (2) even if they did, additional heating would be required to keep the plasma hot as it expands upward. Here we address whether spicules play an important role by injecting plasma at cooler temperatures (<2 MK), which then gets heated to coronal values at higher altitudes. We measure red-blue asymmetries in line profiles formed over a wide range of temperatures in the bright moss areas of two active regions. We derive emission measure distributions from the excess wing emission. We find that the asymmetries and emission measures are small and conclude that spicules do not inject an important (dominant) mass flux into the cores of active regions at temperatures >0.6 MK (log T > 5.8). These conclusions apply not only to spicules but also to any process that suddenly heats and accelerates chromospheric plasma (e.g., a chromospheric nanoflare). The traditional picture of coronal heating and chromospheric evaporation appears to remain the most likely explanation of the active region corona.

  16. The transient distributions of nuclear weapon-generated tritium and its decay product 3 He in the Mediterranean Sea, 1952-2011, and their oceanographic potential

    NASA Astrophysics Data System (ADS)

    Roether, W.; Jean-Baptiste, P.; Fourré, E.; Sültenfuß, J.

    2013-10-01

    We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon testing in the 1950s and early 1960s, based on essentially all available observations. Tritium in surface waters rose to 20-30 TU in 1964 (TU = 1018 × [3H]/H]), a factor of about 100 above the natural level, and thereafter declined 30-fold up to 2011. The decline was largely due to radioactive tritium decay, which produced significant amounts of its stable daughter 3He. We present the scheme by which we separate the tritiugenic part of 3He and the part due to release from the sea floor (terrigenic part). We show that the tritiugenic component can be quantified throughout the Mediterranean waters, typically to a ± 0.15 TU equivalent, mostly because the terrigenic part is low in 3He. This fact makes the Mediterranean unique in offering a potential for the use of tritiugenic 3He as a tracer. The transient distributions of the two tracers are illustrated by a number of sections spanning the entire sea and relevant features of their distributions are noted. By 2011, the 3He concentrations in the top few hundred metres had become low, in response to the decreasing tritium concentrations combined with a flushing out by the general westward drift of these waters. Tritium-3He ages in Levantine Intermediate Water (LIW) were obtained repeated in time at different locations, defining transit times from the LIW source region east of Rhodes. The ages show an upward trend with the time elapsed since the surface-water tritium maximum, which arises because the repeated observations represent increasingly slower moving parts of the full transit time spectrum of LIW. The transit time dispersion revealed by this new application of tritium-3He dating is considerable. We find mean transit times of 12 ± 2 yr up to the Strait of Sicily, 18 ± 3 yr up to the Tyrrhenian Sea, and 22 ± 4 yr up into the Western Mediterranean

  17. The transient distributions of nuclear weapon-generated tritium and its decay product 3He in the Mediterranean Sea, 1952-2011, and their oceanographic potential

    NASA Astrophysics Data System (ADS)

    Roether, W.; Jean-Baptiste, P.; Fourré, E.; Sültenfuß, J.

    2013-04-01

    We present a comprehensive account of tritium and 3He in the Mediterranean Sea since the appearance of the tritium generated by the atmospheric nuclear-weapon testing in the 1950's and early 1960's, based on essentially all available observations. Tritium in surface waters rose to 20-30 TU in 1964 (TU = 1018 · [3H]/[H]), a factor of about 100 above the natural level, and thereafter declined 30-fold up to 2011. The decline was largely due to radioactive tritium decay, which produced significant amounts of its stable daughter 3He. We present the scheme by which we separate the tritiugenic part of 3He and the part due to release from the sea floor (terrigenic part). We show that the tritiugenic component can be quantified throughout the Mediterranean waters, typically to a ±0.15 TU equivalent, mostly because the terrigenic part is low in 3He. This fact makes the Mediterranean unique in offering a potential for the use of tritiugenic 3He as a tracer. The transient distributions of the two tracers are illustrated by a number of sections spanning the entire sea and relevant features of their distributions are noted. By 2011, the 3He concentrations in the top few hundred meters had become low, in response to the decreasing tritium concentrations combined with a flushing out by the general westward drift of these waters. Tritium-3He ages in Levantine Intermediate Water (LIW) were obtained repeated in time at different locations, defining transit times from the LIW source region east of Rhodes. The ages show an upward trend with the time elapsed since the surface-water tritium maximum, which arises because the repeated observations represent increasingly slower moving parts of the full transit time spectrum of LIW. The transit time dispersion found by this new application of tritium-3He dating is considerable. We find mean transit times of 12 ± 2 yr up to the Strait of Sicily, 18 ± 3 yr up to the Tyrrhenian Sea, and 22 ± 4 yr up into the Western Mediterranean. We

  18. Making the Grid "Smart" Through "Smart" Microgrids: Real-Time Power Management of Microgrids with Multiple Distributed Generation Sources Using Intelligent Control

    SciTech Connect

    Nehrir, M. Hashem

    2016-10-20

    investigated the following: • Intelligent load control - demand response (DR) - for frequency stabilization in islanded MGs (partially supported by PNNL). • The impact of high penetration of solar photovoltaic (PV)-generated power at the distribution level (partially supported by PNNL). • The application of AI approaches to renewable (wind, PV) power forecasting (proposed by the reviewers of our proposal). • Application of AI approaches and DR for real-time MG power management (partially supported by NEC Labs-America) • Application of DR in dealing with the variability of wind power • Real-time MG power management using DR and storage (partially supported by NEC Labs-America) • Application of DR in enhancing the performance of load-frequency controller • MAS-based whole-sale and retail power market design for smart grid A

  19. High-efficiency grid-connected photovoltaic module integrated converter system with high-speed communication interfaces for small-scale distribution power generation

    SciTech Connect

    Choi, Woo-Young; Lai, Jih-Sheng

    2010-04-15

    This paper presents a high-efficiency grid-connected photovoltaic (PV) module integrated converter (MIC) system with reduced PV current variation. The proposed PV MIC system consists of a high-efficiency step-up DC-DC converter and a single-phase full-bridge DC-AC inverter. An active-clamping flyback converter with a voltage-doubler rectifier is proposed for the step-up DC-DC converter. The proposed step-up DC-DC converter reduces the switching losses by eliminating the reverse-recovery current of the output rectifying diodes. To reduce the PV current variation introduced by the grid-connected inverter, a PV current variation reduction method is also suggested. The suggested PV current variation reduction method reduces the PV current variation without any additional components. Moreover, for centralized power control of distributed PV MIC systems, a PV power control scheme with both a central control level and a local control level is presented. The central PV power control level controls the whole power production by sending out reference power signals to each individual PV MIC system. The proposed step-up DC-DC converter achieves a high-efficiency of 97.5% at 260 W output power to generate the DC-link voltage of 350 V from the PV voltage of 36.1 V. The PV MIC system including the DC-DC converter and the DC-AC inverter achieves a high-efficiency of 95% with the PV current ripple less than 3% variation of the rated PV current. (author)

  20. Second-Harmonic Generation in Vertically Coupled InAs/GaAs Quantum Dots with a Gaussian Potential Distribution: Combined Effects of Electromagnetic Fields, Pressure, and Temperature

    NASA Astrophysics Data System (ADS)

    Ben Mahrsia, R.; Choubani, M.; Bouzaiene, L.; Maaref, H.

    2015-08-01

    Simulation of quantum dots (QD) is usually performed on the basis of abrupt changes between neighboring materials. In practice, it is not possible to construct such QD because in a real structure the interface between two adjacent materials is not a step. In the work discussed in this paper, vertically coupled InAs/GaAs quantum dots (VCQD) with a non-abrupt change between two neighboring materials are considered. A potential function in the form of a Gaussian distribution was used to show this effect. We also focused on studying the effect of structure, applied electric ( F) and magnetic ( B) fields, pressure ( P), and temperature ( T) on second-harmonic generation (SHG). The analytical expression for SHG was investigated theoretically by use of the density matrix approach, the effective mass, and the finite-difference method (FDM). It was found that the major resonant peak value of SHG is a non-monotonic function of the barrier width ( L B). Moreover, the major resonant peak of SHG is blue-shifted (red-shifted) and its magnitude increases (decreases) monotonically with increasing temperature (pressure). The results obtained also show that the magnitude and position of the resonant peaks of SHG are affected by changes in external conditions, for example applied electric and magnetic fields, structural dimensions of the coupled QD system, and relaxation time ( T 0). Calculations also show that SHG in a VCQD structure with a non-abrupt potential change can be controlled and optimized by appropriate choice of structural dimensions and the external conditions mentioned above.

  1. The potential for distributed generation in Japanese prototype buildings: A DER-CAM analysis of policy, tariff design, building energy use, and technology development (English Version)

    SciTech Connect

    Zhou, Nan; Marnay, Chris; Firestone, Ryan; Gao, Weijun; Nishida, Masaru

    2004-10-15

    The August 2003 blackout of the northeastern U.S. and CANADA caused great economic losses and inconvenience to New York City and other affected areas. The blackout was a warning to the rest of the world that the ability of conventional power systems to meet growing electricity demand is questionable. Failure of large power systems can lead to serious emergencies. Introduction of on-site generation, renewable energy such as solar and wind power and the effective utilization of exhaust heat is needed, to meet the growing energy demands of the residential and commercial sectors. Additional benefit can be achieved by integrating these distributed technologies into distributed energy resource (DER) systems. This work demonstrates a method for choosing and designing economically optimal DER systems. An additional purpose of this research is to establish a database of energy tariffs, DER technology cost and performance characteristics, and building energy consumption for Japan. This research builds on prior DER studies at the Ernest Orlando Lawrence Berkeley National Laboratory (LBNL) and with their associates in the Consortium for Electric Reliability Technology Solutions (CERTS) and operation, including the development of the microgrid concept, and the DER selection optimization program, the Distributed Energy Resources Customer Adoption Model (DER-CAM). DER-CAM is a tool designed to find the optimal combination of installed equipment and an idealized operating schedule to minimize a site's energy bills, given performance and cost data on available DER technologies, utility tariffs, and site electrical and thermal loads over a test period, usually an historic year. Since hourly electric and thermal energy data are rarely available, they are typically developed by building simulation for each of six end use loads used to model the building: electric-only loads, space heating, space cooling, refrigeration, water heating, and natural-gas-only loads. DER-CAM provides a

  2. Effect of Winglets on a First-Generation Jet Transport Wing. 2: Pressure and Spanwise Load Distributions for a Semispan Model at High Subsonic Speeds. [in the Langley 8 ft transonic tunnel

    NASA Technical Reports Server (NTRS)

    Montoya, L. C.; Flechner, S. G.; Jacobs, P. F.

    1977-01-01

    Pressure and spanwise load distributions on a first-generation jet transport semispan model at high subsonic speeds are presented for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. Selected data are discussed to show the general trends and effects of the various configurations.

  3. Effect of winglets on a first-generation jet transport wing. 3: Pressure and spanwise load distributions for a semispan model at Mach 0.30. [in the Langley 8 ft transonic tunnel

    NASA Technical Reports Server (NTRS)

    Montoya, L. C.; Jacobs, P. F.; Flechner, S. G.

    1977-01-01

    Pressure and spanwise load distributions on a first-generation jet transport semispan model at a Mach number of 0.30 are given for the basic wing and for configurations with an upper winglet only, upper and lower winglets, and a simple wing-tip extension. To simulate second-segment-climb lift conditions, leading- and/or trailing-edge flaps were added to some configurations.

  4. The Generational Intelligence Gains Are Caused by Decreasing Variance in the Lower Half of the Distribution: Supporting Evidence for the Nutrition Hypothesis

    ERIC Educational Resources Information Center

    Colom, R.; Lluis-Font, J.M.; Andres-Pueyo, A.

    2005-01-01

    Generational intelligence gains are one intriguing finding in science. Nutrition and cognitive stimulation are among the most remarkable causes of the upward trend in intelligence. The nutrition hypothesis predicts a primary impact on the most deprived, producing disproportionate gains at low intelligence levels. The cognitive stimulation…

  5. Development of activity pencil beam algorithm using measured distribution data of positron emitter nuclei generated by proton irradiation of targets containing {sup 12}C, {sup 16}O, and {sup 40}Ca nuclei in preparation of clinical application

    SciTech Connect

    Miyatake, Aya; Nishio, Teiji; Ogino, Takashi

    2011-10-15

    Purpose: The purpose of this study is to develop a new calculation algorithm that is satisfactory in terms of the requirements for both accuracy and calculation time for a simulation of imaging of the proton-irradiated volume in a patient body in clinical proton therapy. Methods: The activity pencil beam algorithm (APB algorithm), which is a new technique to apply the pencil beam algorithm generally used for proton dose calculations in proton therapy to the calculation of activity distributions, was developed as a calculation algorithm of the activity distributions formed by positron emitter nuclei generated from target nuclear fragment reactions. In the APB algorithm, activity distributions are calculated using an activity pencil beam kernel. In addition, the activity pencil beam kernel is constructed using measured activity distributions in the depth direction and calculations in the lateral direction. {sup 12}C, {sup 16}O, and {sup 40}Ca nuclei were determined as the major target nuclei that constitute a human body that are of relevance for calculation of activity distributions. In this study, ''virtual positron emitter nuclei'' was defined as the integral yield of various positron emitter nuclei generated from each target nucleus by target nuclear fragment reactions with irradiated proton beam. Compounds, namely, polyethylene, water (including some gelatin) and calcium oxide, which contain plenty of the target nuclei, were irradiated using a proton beam. In addition, depth activity distributions of virtual positron emitter nuclei generated in each compound from target nuclear fragment reactions were measured using a beam ON-LINE PET system mounted a rotating gantry port (BOLPs-RGp). The measured activity distributions depend on depth or, in other words, energy. The irradiated proton beam energies were 138, 179, and 223 MeV, and measurement time was about 5 h until the measured activity reached the background level. Furthermore, the activity pencil beam data

  6. Thermodynamic estimation of minor element distribution between immiscible liquids in Fe-Cu-based metal phase generated in melting treatment of municipal solid wastes

    SciTech Connect

    Lu, X.; Nakajima, K.; Sakanakura, H.; Matsubae, K.; Bai, H.; Nagasaka, T.

    2012-06-15

    Graphical abstract: Display Omitted Highlights: Black-Right-Pointing-Pointer Two liquids separation of metal occurs in the melting of municipal solid waste. Black-Right-Pointing-Pointer The distribution of PGMs etc. between two liquid metal phases is studied. Black-Right-Pointing-Pointer Quite simple thermodynamic model is applied to predict the distribution ratio. Black-Right-Pointing-Pointer Au and Ag originated from WEEE are found to be concentrated into Cu-rich phase. - Abstract: Waste electrical and electronic equipment (WEEE) has become an important target in managing material cycles from the viewpoint of not only waste management and control of environmental pollution but also resource conservation. This study investigated the distribution tendency of trace elements in municipal solid waste (MSW) or incinerator ash, including valuable non-ferrous metals (Ni, Co, Cr, Mn, Mo, Ti, V, W, Zr), precious group metals (PGMs) originated from WEEE (Ag, Au, Pd, Pt), and others (Al, B, Pb, Si), between Fe-rich and Cu-rich metal phases by means of simple thermodynamic calculations. Most of the typical alloying elements for steel (Co, Cr, Mo, Nb, Ni, Si, Ti, V, and W) and Rh were preferentially distributed into the Fe-rich phase. PGMs, such as Au, Ag, and Pd, were enriched in the Cu-rich phase, whereas Pt was almost equally distributed into both phases. Since the primary metallurgical processing of Cu is followed by an electrolysis for refining, and since PGMs in crude copper have been industrially recovered from the resulting anode slime, our results indicated that Ag, Au, and Pd could be effectively recovered from MSW if the Cu-rich phase could be selectively collected.

  7. Photonic generation of stable microwave signals from a dual-wavelength Al2O3:Yb3+ distributed-feedback waveguide laser.

    PubMed

    Bernhardi, E H; Khan, M R H; Roeloffzen, C G H; van Wolferen, H A G M; Wörhoff, K; de Ridder, R M; Pollnau, M

    2012-01-15

    We report the fabrication and characterization of a dual-wavelength distributed-feedback channel waveguide laser in ytterbium-doped aluminum oxide. Operation of the device is based on the optical resonances that are induced by two local phase shifts in the distributed-feedback structure. A stable microwave signal at ~15 GHz with a -3 dB width of 9 kHz was subsequently created via the heterodyne photodetection of the two laser wavelengths. The long-term frequency stability of the microwave signal produced by the free-running laser is better than ±2.5 MHz, while the power of the microwave signal is stable within ±0.35 dB.

  8. Precise hypocenter distribution and earthquake generating and stress in and around the upper-plane seismic belt in the subducting Pacific slab beneath NE Japan

    NASA Astrophysics Data System (ADS)

    Kita, S.; Okada, T.; Nakajima, J.; Matsuzawa, T.; Uchida, N.; Hasegawa, A.

    2007-12-01

    1. Introduction We found an intraslab seismic belt (upper-plane seismic belt) in the upper plane of the double seismic zone within the Pacific slab, running interface at depths of 70-100km beneath the forearc area. The location of the deeper limits of this belt appears to correspond to one of the facies boundaries (from jadeite lawsonite blueschist to lawsonite amphibole eclogite) in the oceanic crust [Kita et al., 2006, GRL]. In this study, we precisely relocated intraslab earthquakes by using travel time differences calculated by the waveform cross-spectrum analysis to obtain more detailed distribution of the upper plane-seismic belt within the Pacific slab beneath NE Japan. We also discuss the stress field in the slab by examining focal mechanisms of the earthquakes. 2. Data and Method We relocated events at depths of 50-00 km for the period from March 2003 to November 2006 from the JMA earthquake catalog. We applied the double-difference hypocenter location method (DDLM) by Waldhauser and Ellsworth (2000) to the arrival time data of the events. We use relative earthquake arrival times determined both by the waveform cross-spectrum analysis and by the catalog-picking data. We also determine focal mechanisms using the P wave polarity. 3. Spatial distribution of relocated hypocenters In the upper portion of the slab crust, seismicity is very active and distributed relatively homogeneously at depths of about 70-100km parallel to the volcanic front, where the upper-plane seismic belt has been found. In the lower portion of slab crust and/or the uppermost portion of the slab mantle, seismicity is spatially very limited to some small areas (each size is about 20 x 20km) at depths around 65km. Two of them correspond to the aftershock area of the 2003 Miyagi (M7.1) intraslab earthquake and that of the 1987 Iwaizumi (M6.6) intraslab earthquake, respectively. Based on the dehydration embrittelment hypothesis, the difference of the spatial distribution of the seismicity in

  9. Ultrawideband doublet pulse generation based on nonlinear polarization rotation of an elliptically polarized beam and its distribution over a fiber/wireless link.

    PubMed

    Chang, You Min; Lee, Junsu; Lee, Ju Han

    2010-09-13

    Proposed herein is an alternative photonic scheme for the generation of a doublet UWB pulse, which is based on the nonlinear polarization rotation of an elliptically polarized probe beam. The proposed scheme is a modified optical-fiber Kerr shutter that uses an elliptically polarized probe beam together with a linearly polarized control beam. Through theoretical analysis, it was shown that the optical-fiber-based Kerr shutter is capable of producing an ideal transfer function for the successful conversion of input Gaussian pulses into doublet pulses under special elliptical polarization states of the probe beam. An experimental verification was subsequently carried out to verify the working principle. Finally, the system performance of the generated UWB doublet pulses was assessed by propagating them over a 25-km-long standard single-mode fiber link, followed by wireless transmission. Error-free transmission was successfully achieved.

  10. Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

    DOEpatents

    Maris, Humphrey J.

    2003-01-01

    A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

  11. Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

    DOEpatents

    Maris, Humphrey J.

    2002-01-01

    A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

  12. Three-zonal engineering method of heat calculation for fluidized bed furnaces based on data on commercial investigations of heat generation distribution during biomass combustion

    NASA Astrophysics Data System (ADS)

    Litun, D. S.; Ryabov, G. A.

    2016-02-01

    A three-zonal method of heat calculation of furnaces for combustion of biomass and low-caloric fuel in the fluidized bed is described. The method is based on equations of thermal and material balances that account for heat generation by fuel in the zone, heat-and-mass transfer heat exchange between the furnace media and surfaces that bound the zone, and heat-and-mass transfer between furnace zones. The calculation procedure for heat generation by fuel in the fluidized bed (FB) using the heat generation portion by the fuel is proposed. Based on commercial investigations, the main factors that affect the average temperature in the FB and the portion of fuel heat that is released in the FB are determined. Results of commercial investigations showed that the airflow coefficient in the FB should be recognized as the main operation parameter that affects the average temperature in the FB and, consequently, heat generation in the FB. The gas flow rate in the FB can be marked out as the second factor that affects the consumption degree of oxidizer supplied in the FB. Commercial investigations revealed that mixing is affected by the gas flow rate in the FB and the bed material particle size, which may be changed during the boiler operation because of the agglomeration of particles of sand and ash. The calculation processing of commercial investigations on a KM-75-40M boiler of a CHP-3 of an Arkhangelsk Pulp and Paper Mill (APPM), which was carried out using the inverse problem procedure by means of a developed computer program, determined the range of the fuel heat release share in the FB, which was 0.26-0.45 at an excess air factor of 0.59-0.93 in the bed, and the heat release share in the maximum temperature zone in the total heat release in the superbed space. The heat release share in the bed is determined as an approximating function of the excess air factor in the bed and the fluidization number. The research results can be used during designing boilers with the

  13. An on-line monitoring system for oil-film, pressure and temperature distributions in large-scale hydro-generator bearings

    NASA Astrophysics Data System (ADS)

    Höbel, M.; Haffner, K.

    1999-05-01

    Instrumentation that allows the behaviour of a hydro-generator thrust bearing to be monitored during operation is described. The measurement system was developed at the Asea Brown Boveri corporate research centre in Switzerland and was tested under realistic operating conditions at the Harbin Electric Machinery Company bearing-testing facility in the People's Republic of China. Newly developed fibre-optical proximity probes were used for the on-line monitoring of the thin oil film between the static and rotating parts of the bearing. These sensors are based on a back-reflection technique and can be used for various target materials such as Babbitt and Teflon. The monitoring system comprises about 120 temperature sensors, four pressure sensors and five optical oil-film thickness sensors. Temperature sensors are installed at specific static locations, whereas pressure and oil-film sensors are positioned in the runner and generate data during rotation. A special feature of the monitoring equipment is its on-line processing capability. Digital signal processors operating in parallel handle pressure and oil-film thickness data. Important measurement parameters such as the maximum pressure, maximum temperature and minimum oil-film thickness are displayed on-line. Detailed three-dimensional temperature information on one of the load segments can be obtained from subsequent off-line data analysis. The system also calculates two-dimensional plots of the oil-film thickness and pressure for most of the 12 load segments.

  14. Next Generation Power and Energy

    DTIC Science & Technology

    2010-12-02

    Cells Advanced Generators Direct Conversion Photovoltaics Future Fuels Energy Storage Batteries Capacitors Flywheels Motors & Actuators Motors Actuators...Generation Power Distribution Energy Storage Power Conversion Propulsion Ship’s Power Sources Mission Systems Industry Competes for Components; ‘Submit...Chiller Technologies / HVAC ONR Maintaining Robust S&T Investment Power LoadSystem Control Power Generation Power Distribution Energy Storage Power

  15. Distributions of {beta}{sup +} decayed nuclei generated in the CH{sub 2} and H{sub 2}O targets by the target nuclear fragment reaction using therapeutic MONO and SOBP proton beam

    SciTech Connect

    Nishio, Teiji; Sato, Takashi; Kitamura, Hideaki; Murakami, Koji; Ogino, Takashi

    2005-04-01

    In proton radiotherapy, the irradiation dose can be concentrated on a tumor. To use this radiotherapy efficiently in the clinical field, it is necessary to evaluate the proton-irradiated area and condition. The proton-irradiated area can be confirmed by coincidence detection of pair annihilation gamma rays from {beta}{sup +} decayed nuclei generated by target nuclear fragment reaction of irradiated proton nuclei and nuclei in the irradiation target. In this study, we performed experiments of proton irradiation to a polyethylene (PE:CH{sub 2}) target containing {sup 12}C nuclei, which is a major component of the human body, and a gelatinous water (H{sub 2}O) target containing {sup 16}O nuclei at different proton irradiation energy levels under different beam conditions of mono-energetic Bragg peak and spread-out Bragg peak. The distribution of the activity in the target after proton irradiation was measured by a positron emission tomography (PET) apparatus, and compared with the calculated distribution. The temporal dependence of the activity distribution during the period between the completion of proton irradiation and the start of measurement by the PET apparatus was examined. The activity by clinical proton irradiation was 3 kB/cc in the PE target and 13 kB/cc in the water target, indicating that the intensity was sufficient for the evaluation of the distribution. The range of the activity distribution against the physical range was short (several millimeter water equivalent length), indicating the presence of target dependence. The range difference in the water target was slightly large with time dependence until the start of measurement. The difference of the lateral widths with full width half at maximum in the distributions of the measured irradiated dose and activity was within 1 mm.

  16. Economic feasibility analysis of distributed electric power generation based upon the natural gas fired fuel cell. Draft and final progress report for the period May 1, 1993--July 31, 1993

    SciTech Connect

    Not Available

    1993-09-01

    This report is an account of the work performed from May 1, 1993 to July 30,1993 on the economic feasibility generating electrical power by natural gas-fired fuel cells. The study is comprised of a survey of energy users, the development of numeric models of an energy distribution system and a central plant utilities system that includes a fuel cell. A model of the capital cost of the hardware elements is combined with a series of ownership scenarios and an operations model that provide the necessary input for a model of the cost of ownership of a fuel cell-based power generation system. The primary model development tasks are complete. The remaining study emphasis is to perform an economic analysis of varied ownership scenarios using the model. This report outlines the progress to date.

  17. Power System Concepts for the Lunar Outpost: A Review of the Power Generation, Energy Storage, Power Management and Distribution (PMAD) System Requirements and Potential Technologies for Development of the Lunar Outpost

    NASA Technical Reports Server (NTRS)

    Khan, Z.; Vranis, A.; Zavoico, A.; Freid, S.; Manners, B.

    2006-01-01

    This paper will review potential power system concepts for the development of the lunar outpost including power generation, energy storage, and power management and distribution (PMAD). In particular, the requirements of the initial robotic missions will be discussed and the technologies considered will include cryogenics and regenerative fuel cells (RFC), AC and DC transmission line technology, high voltage and low voltage power transmission, conductor materials of construction and power beaming concepts for transmitting power to difficult to access locations such as at the bottom of craters. Operating conditions, component characteristics, reliability, maintainability, constructability, system safety, technology gaps/risk and adaptability for future lunar missions will be discussed for the technologies considered.

  18. Regional distribution of styrene analogues generated from polystyrene degradation along the coastlines of the North-East Pacific Ocean and Hawaii.

    PubMed

    Kwon, Bum Gun; Saido, Katsuhiko; Koizumi, Koshiro; Sato, Hideto; Ogawa, Naoto; Chung, Seon-Yong; Kusui, Takashi; Kodera, Yoichi; Kogure, Kazuhio

    2014-05-01

    Beach sand and seawater taken from the coastlines of the North-East Pacific Ocean and Hawaii State were investigated to determine the causes of global chemical contamination from polystyrene (PS). All samples were found to contain styrene monomer (SM), styrene dimers (SD), and styrene trimers (ST) with a concentration distribution of styrene analogues in the order of ST > SD > SM. The contamination by styrene analogues along the West Coast proved more severe than in Alaska and other regions. The Western Coastlines of the USA seem be affected by both land- and ocean-based pollution sources, which might result from it being a heavily populated area as the data suggest a possible proportional relationship between PS pollution and population. Our results suggest the presence of new global chemical contaminants derived from PS in the ocean, and along coasts.

  19. An approach for generating trajectory-based dynamics which conserves the canonical distribution in the phase space formulation of quantum mechanics. II. Thermal correlation functions

    SciTech Connect

    Liu Jian; Miller, William H.

    2011-03-14

    We show the exact expression of the quantum mechanical time correlation function in the phase space formulation of quantum mechanics. The trajectory-based dynamics that conserves the quantum canonical distribution-equilibrium Liouville dynamics (ELD) proposed in Paper I is then used to approximately evaluate the exact expression. It gives exact thermal correlation functions (of even nonlinear operators, i.e., nonlinear functions of position or momentum operators) in the classical, high temperature, and harmonic limits. Various methods have been presented for the implementation of ELD. Numerical tests of the ELD approach in the Wigner or Husimi phase space have been made for a harmonic oscillator and two strongly anharmonic model problems, for each potential autocorrelation functions of both linear and nonlinear operators have been calculated. It suggests ELD can be a potentially useful approach for describing quantum effects for complex systems in condense phase.

  20. An approach for generating trajectory-based dynamics which conserves the canonical distribution in the phase space formulation of quantum mechanics. II. Thermal correlation functions

    NASA Astrophysics Data System (ADS)

    Liu, Jian; Miller, William H.

    2011-03-01

    We show the exact expression of the quantum mechanical time correlation function in the phase space formulation of quantum mechanics. The trajectory-based dynamics that conserves the quantum canonical distribution-equilibrium Liouville dynamics (ELD) proposed in Paper I is then used to approximately evaluate the exact expression. It gives exact thermal correlation functions (of even nonlinear operators, i.e., nonlinear functions of position or momentum operators) in the classical, high temperature, and harmonic limits. Various methods have been presented for the implementation of ELD. Numerical tests of the ELD approach in the Wigner or Husimi phase space have been made for a harmonic oscillator and two strongly anharmonic model problems, for each potential autocorrelation functions of both linear and nonlinear operators have been calculated. It suggests ELD can be a potentially useful approach for describing quantum effects for complex systems in condense phase.