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Sample records for nanoflare distribution generated

  1. 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.

  2. 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.

  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. COMBINING PARTICLE ACCELERATION AND CORONAL HEATING VIA DATA-CONSTRAINED CALCULATIONS OF NANOFLARES IN CORONAL LOOPS

    SciTech Connect

    Gontikakis, C.; Efthymiopoulos, C.; Georgoulis, M. K.; Patsourakos, S.; Anastasiadis, A.

    2013-07-10

    We model nanoflare heating of extrapolated active-region coronal loops via the acceleration of electrons and protons in Harris-type current sheets. The kinetic energy of the accelerated particles is estimated using semi-analytical and test-particle-tracing approaches. Vector magnetograms and photospheric Doppler velocity maps of NOAA active region 09114, recorded by the Imaging Vector Magnetograph, were used for this analysis. A current-free field extrapolation of the active-region corona was first constructed. The corresponding Poynting fluxes at the footpoints of 5000 extrapolated coronal loops were then calculated. Assuming that reconnecting current sheets develop along these loops, we utilized previous results to estimate the kinetic energy gain of the accelerated particles. We related this energy to nanoflare heating and macroscopic loop characteristics. Kinetic energies of 0.1-8 keV (for electrons) and 0.3-470 keV (for protons) were found to cause heating rates ranging from 10{sup -6} to 1 erg s{sup -1} cm{sup -3}. Hydrodynamic simulations show that such heating rates can sustain plasma in coronal conditions inside the loops and generate plasma thermal distributions that are consistent with active-region observations. We concluded the analysis by computing the form of X-ray spectra generated by the accelerated electrons using the thick-target approach. These spectra were found to be in agreement with observed X-ray spectra, thus supporting the plausibility of our nanoflare-heating scenario.

  10. 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.

  11. 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.

  12. "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.

  13. Nanoflare Statistics from First Principles: Fractal Geometry and Temperature Synthesis

    NASA Astrophysics Data System (ADS)

    Aschwanden, Markus J.; Parnell, Clare E.

    2002-06-01

    We derive universal scaling laws for the physical parameters of flarelike processes in a low-β plasma, quantified in terms of spatial length scales l, area A, volume V, electron density ne, electron temperature Te, total emission measure M, and thermal energy E. The relations are specified as functions of two independent input parameters, the power index a of the length distribution, N(l)~l-a, and the fractal Haussdorff dimension D between length scales l and flare areas, A(l)~lD. For values that are consistent with the data, i.e., a=2.5+/-0.2 and D=1.5+/-0.2, and assuming the RTV scaling law, we predict an energy distribution N(E)~E-α with a power-law coefficient of α=1.54+/-0.11. As an observational test, we perform statistics of nanoflares in a quiet-Sun region covering a comprehensive temperature range of Te~1-4 MK. We detected nanoflare events in extreme-ultraviolet (EUV) with the 171 and 195 Å filters from the Transition Region and Coronal Explorer (TRACE), as well as in soft X-rays with the AlMg filter from the Yohkoh soft X-ray telescope (SXT), in a cospatial field of view and cotemporal time interval. The obtained frequency distributions of thermal energies of nanoflares detected in each wave band separately were found to have power-law slopes of α~1.86+/-0.07 at 171 Å (Te~0.7-1.1 MK), α~1.81+/-0.10 at 195 Å (Te~1.0-1.5 MK), and α~1.57+/-0.15 in the AlMg filter (Te~1.8-4.0 MK), consistent with earlier studies in each wavelength. We synthesize the temperature-biased frequency distributions from each wavelength and find a corrected power-law slope of α~1.54+/-0.03, consistent with our theoretical prediction derived from first principles. This analysis, supported by numerical simulations, clearly demonstrates that previously determined distributions of nanoflares detected in EUV bands produced a too steep power-law distribution of energies with slopes of α~2.0-2.3 mainly because of this temperature bias. The temperature-synthesized distributions of

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. A Survey of Nanoflare Properties in Active Regions Observed with the Solar Dynamics Observatory

    NASA Astrophysics Data System (ADS)

    Viall, Nicholeen M.; Klimchuk, James A.

    2017-06-01

    In this paper, we examine 15 different active regions (ARs) observed with the Solar Dynamics Observatory and analyze their nanoflare properties. We have recently developed a technique that systematically identifies and measures plasma temperature dynamics by computing time lags between light curves. The time lag method tests whether the plasma is maintained at a steady temperature, or if it is dynamic, undergoing heating and cooling cycles. An important aspect of our technique is that it analyzes both observationally distinct coronal loops as well as the much more prevalent diffuse emission between them. We find that the widespread cooling reported previously for NOAA AR 11082 is a generic property of all ARs. The results are consistent with impulsive nanoflare heating followed by slower cooling. Only occasionally, however, is there full cooling from above 7 MK to well below 1 MK. More often, the plasma cools to approximately 1-2 MK before being reheated by another nanoflare. These same 15 ARs were first studied by Warren et al. We find that the degree of cooling is not well correlated with the reported slopes of the emission measure distribution. We also conclude that the Fe xviii emitting plasma that they measured is mostly in a state of cooling. These results support the idea that nanoflares have a distribution of energies and frequencies, with the average delay between successive events on an individual flux tube being comparable to the plasma cooling timescale.

  19. 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.

  20. 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.

  1. 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.

  2. Common origin of kinetic scale turbulence and the electron halo in the solar wind – Connection to nanoflares

    SciTech Connect

    Che, Haihong

    2016-03-25

    We summarize our recent studies on the origin of solar wind kinetic scale turbulence and electron halo in the electron velocity distribution function. Increasing observations of nanoflares and microscopic type III radio bursts strongly suggest that nanoflares and accelerated electron beams are common in the corona. Based on particle-in-cell simulations, we show that both the core-halo feature and kinetic scale turbulence observed in the solar wind can be produced by the nonlinear evolution of electron two-stream instability driven by nanoflare accelerated electron beams. The energy exchange between waves and particles reaches equilibrium in the inner corona and the key features of the turbulence and velocity distribution are preserved as the solar wind escapes into interplanetary space along open magnetic field lines. Observational tests of the model and future theoretical work are discussed.

  3. 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

  4. 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).

  5. 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.

  6. 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).

  7. 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)

  8. ScienceCast 176: The Mystery of Nanoflares

    NASA Image and Video Library

    2015-03-18

    Tiny solar flares on the sun may be having an outsized effect on the temperature of the sun's atmosphere. To investigate, scientists will observe these "nanoflares" using a space telescope built for black holes.

  9. 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.

  10. 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.

  11. Energy dissipation in magnetohydrodynamic turbulence: coherent structures or 'nanoflares'?

    SciTech Connect

    Zhdankin, Vladimir; Boldyrev, Stanislav; Perez, Jean Carlos; Tobias, Steven M.

    2014-11-10

    We investigate the intermittency of energy dissipation in magnetohydrodynamic (MHD) turbulence by identifying dissipative structures and measuring their characteristic scales. We find that the probability distribution of energy dissipation rates exhibits a power-law tail with an index very close to the critical value of –2.0, which indicates that structures of all intensities contribute equally to energy dissipation. We find that energy dissipation is uniformly spread among coherent structures with lengths and widths in the inertial range. At the same time, these structures have thicknesses deep within the dissipative regime. As the Reynolds number is increased, structures become thinner and more numerous, while the energy dissipation continues to occur mainly in large-scale coherent structures. This implies that in the limit of high Reynolds number, energy dissipation occurs in thin, tightly packed current sheets which nevertheless span a continuum of scales up to the system size, exhibiting features of both coherent structures and nanoflares previously conjectured as a coronal heating mechanism.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Aptamer Nano-Flares for Molecular Detection in Living Cells

    PubMed Central

    Zheng, Dan; Seferos, Dwight S.; Giljohann, David A.; Patel, Pinal C.; Mirkin, Chad A.

    2011-01-01

    We demonstrate a composite nanomaterial, termed an aptamer nano-flare, that can directly quantify an intracellular analyte in a living cell. Aptamer nano-flares consist of a gold nanoparticle core functionalized with a dense monolayer of nucleic acid aptamers with a high affinity for adenosine triphosphate (ATP). The probes bind selectively to target molecules and release fluorescent reporters which indicate the presence of the analyte. Additionally, these nanoconjugates are readily taken up by cells where their signal intensity can be used to quantify intracellular analyte concentration. These nanoconjugates are a promising approach for the intracellular quantification of other small molecules or proteins, or as agents that use aptamer binding to elicit a biological response in living systems. PMID:19645478

  18. Observation of nano-flares and transient coronal heating

    NASA Astrophysics Data System (ADS)

    Serge, Koutchmy; Golub, Leon; Bazin, Cyrille; Tavabi, Ehsan

    Nano-flares are the best candidate for heating the bulk of the corona but their signature is still not clearly recognized in the data. The Hinode XRT provided many high resolution partial frame sequences that allowed study of intermittent flash events in quiet areas, suggesting a definite signature of nano-flares. The Yohkoh so-called SXR transient brightenings are now recorded by XRT with a wealth of detail. The typical resolution and low noise of XRT permits detection at a much lower intensity threshold and a much shorter duration. In order to evaluate what is a nano-flare, we selected a well-observed solar disk event seen at the beginning of the XRT mission, when the Sun was still very quiet. This single flare event is recorded outside of any active region and does not show any GOES or RHESSI signature, even at the lowest level. This nano-flare shows structures suggestive of rather horizontal low lying loops with a short intense flash phase. No jet is observed. EUV brightening counterparts exist, including the 304Å TR emission, detected by the SECCHI EUV imagers on the two STEREO spacecrafts. Filtergrams taken simultaneously at a fast rate in Hα are deeply processed to look at the resulting effects, seen as a faint brightening and a cool transient very small scale feature. We argue in favor of many similar SXR events permanently occurring at the TR levels, not showing strong EUV brightenings but with horizontally stretched structures similar to the recently described Hi-C reconnection events called magnetic “braids” that include twists and possibly counter flows.

  19. 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

  20. 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.

  1. 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. Copyright © 2014, American Association for the Advancement of Science.

  2. 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.

  3. Nanoflare Properties throughout Active Regions: Comparing SDO/AIA Observations with Modeled Active Region Light Curves

    NASA Astrophysics Data System (ADS)

    Viall, Nicholeen; Klimchuk, J.

    2012-05-01

    Coronal plasma in active regions is typically measured to be at temperatures near 1-3 MK. Is the majority of the coronal plasma in hydrostatic equilibrium, maintained at these temperatures through a form of quasi-steady heating, or is this simply a measure of the average temperature of widely varying, impulsively heated coronal plasma? Addressing this question is complicated by the fact that the corona is optically thin: many thousands of flux tubes which are heated completely independently are contributing to the total emission along a given line of sight. There is a large body of work focused on the heating of isolated features - coronal loops - which are impulsively heated, however it is the diffuse emission between loops which often comprises the majority of active region emission. Therefore in this study we move beyond isolated features and analyze all of the emission in an entire active region from all contributing flux tubes. We investigate light curves systematically using SDO/AIA observations. We also model the active region corona as a line-of-sight integration of many thousands of completely independently heated flux tubes. The emission from these flux tubes may be time dependent, quasi-steady, or a mix of both, depending on the cadence of heat release. We demonstrate that despite the superposition of randomly heated flux tubes, different distributions of nanoflare cadences produce distinct signatures in light curves observed with multi-wavelength and high time cadence data, such as those from SDO/AIA. We conclude that the majority of the active region plasma is not maintained in hydrostatic equilibrium, rather it is undergoing dynamic heating and cooling cycles. The observed emission is consistent with heating through impulsive nanoflares, whose energy is a function of location within the active region. This research was supported by an appointment to the NASA Postdoctoral Program at GSFC/NASA.

  4. 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}.

  5. Nanoflare Properties throughout Active Regions: Comparing SDO/AIA Observations with Modeled Active Region Light Curves

    NASA Technical Reports Server (NTRS)

    Viall, Nicholeen

    2012-01-01

    Coronal plasma in active regions is typically measured to be at temperatures near 1-3 MK. Is the majority of the coronal plasma in hydrostatic equilibrium, maintained at these temperatures through a form of quasi-steady heating, or is this simply a measure of the average temperature of widely varying, impulsively heated coronal plasma? Addressing this question is complicated by the fact that the corona is optically thin: many thousands of flux tubes which are heated completely independently are contributing to the total emission along a given line of sight. There is a large body of work focused on the heating of isolated features - coronal loops - which are impulsively heated, however it is the diffuse emission between loops which often comprises the majority of active region emission. Therefore in this study we move beyond isolated features and analyze all of the emission in an entire active region from all contributing flux tubes. We investigate light curves systematically using SDO/AIA observations. We also model the active region corona as a line-of-sight integration of many thousands of completely independently heated flux tubes. The emission from these flux tubes may be time dependent, quasi-steady, or a mix of both, depending on the cadence of heat release. We demonstrate that despite the superposition of randomly heated flux tubes, different distributions of nanoflare cadences produce distinct signatures in light curves observed with multi-wavelength and high time cadence data, such as those from SDO/AIA. We conclude that the majority of the active region plasma is not maintained in hydrostatic equilibrium, rather it is undergoing dynamic heating and cooling cycles. The observed emission is consistent with heating through impulsive nanoflares, whose energy is a function of location within the active region.

  6. 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.

  7. The Operational Risk Assessment for Distribution Network with Distributed Generations

    NASA Astrophysics Data System (ADS)

    Hua, Xie; Yaqi, Wu; Yifan, Wang; Qian, Sun; Jianwei, Ma

    2017-05-01

    Distribution network is an important part of the power system and is connected to the consumers directly. Many distributed generations that have discontinuous output power are connected in the distribution networks, which may cause adverse impact to the distribution network. Therefore, to ensure the security and reliability of distribution network with numerous distributed generations, the risk analysis is necessary for this kind of distribution networks. After study of stochastic load flow algorithm, this paper applies it in the static security risk assessment. The wind and photovoltaic output probabilistic model are built. The voltage over-limit is chosen to calculate the risk indicators. As a case study, the IEEE 33 system is simulated for analyzing impact of distributed generations on system risk in the proposed method.

  8. 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.

  9. 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.

  10. A Nanoflare-Based Cellular Automaton Model and the Observed Properties of the Coronal Plasma

    NASA Technical Reports Server (NTRS)

    Lopez-Fuentes, Marcelo; Klimchuk, James Andrew

    2016-01-01

    We use the cellular automaton model described in Lopez Fuentes and Klimchuk to study the evolution of coronal loop plasmas. The model, based on the idea of a critical misalignment angle in tangled magnetic fields, produces nanoflares of varying frequency with respect to the plasma cooling time. We compare the results of the model with active region (AR) observations obtained with the Hinode/XRT and SDOAIA instruments. The comparison is based on the statistical properties of synthetic and observed loop light curves. Our results show that the model reproduces the main observational characteristics of the evolution of the plasma in AR coronal loops. The typical intensity fluctuations have amplitudes of 10 percent - 15 percent both for the model and the observations. The sign of the skewness of the intensity distributions indicates the presence of cooling plasma in the loops. We also study the emission measure (EM) distribution predicted by the model and obtain slopes in log(EM) versus log(T) between 2.7 and 4.3, in agreement with published observational values.

  11. A Nanoflare Explanation for the Heating of Coronal Loops Observed by Yohkoh

    NASA Astrophysics Data System (ADS)

    Cargill, P. J.; Klimchuk, J. A.

    1997-03-01

    The nanoflare model of Cargill (1994a) is used to model active region loops observed by the Yohkoh Soft X-ray Telescope (SXT). Using observed information concerning the dimensions and energy-loss rate of each loop, a range of loop models with different temperatures, emission measures, and filling factors is generated. For hot loops (T > 4 × 106 K), it is shown that filling factors less than 0.1 can fit the data, although the uncertainties can be quite large. For cool loops (T ~ 2 × 106 K), the model cannot reproduce the observed temperature and emission measure for any value of the filling factor. Earlier work of Porter & Klimchuk suggested that some of these loops cannot be explained by a steady state heating model either. It is proposed that there may exist two distinct classes of loops and that coronal material is injected into the cooler loops by a mechanism that is not directly related to heating (e.g., not chromospheric evaporation).

  12. 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.

  13. 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.

  14. Reliability Evaluation of Distribution System with Distributed Generation

    NASA Astrophysics Data System (ADS)

    Chen, Guoyan; Zhang, Feng; You, Dahai; Wang, Yong; Lu, Guojun; Zou, Qi; Liu, Hengwei; Qian, Junjie; Xu, Heng

    2017-07-01

    Distribution system reliability assessment is an important part of power system reliability assessment. In recent years, distributed generations (DG) are more and more connected to distribution system because of its flexible and friendly environment features, which imposes a great influence on distribution system reliability. Hence, a reliability evaluation method suitable for distribution system with DG is imperative, which is proposed in this paper. First, a probabilistic model of DG output is established based on the generation characteristics of DG. Second, the island operation mode of distribution system with DG is researched, subsequently, the calculation method of the probability of island successful operation is put forward on the basis of DG model and the load model. Third, a reliability assessment methodology of distribution system with DG is proposed by improving the traditional minimal path algorithm for reliability evaluation of distribution system. Finally, some results are obtained by applying the proposed method to the IEEE-RBTS Bus6 system, which are consistent with the well-known facts. In this way, the proposed method is proved to be reasonable and effective.

  15. Distributed Generation to Counter Grid Vulnerability

    DTIC Science & Technology

    2007-03-27

    destroyed one home, twenty-six acres of trees, and 2.5 miles of vegetation .23 Strategic pipelines represent one of our largest vulnerabilities, as more...selling back any excess electricity to the grid. In this manner, distributed generation could buffer “power spikes,” preventing overload to the overall...years that caused costly reset of equipment and spoilage of product. It now generates 70 percent of its electric and 30 percent of its hot water used

  16. 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.

  17. Fuel cells for distributed power generation

    NASA Astrophysics Data System (ADS)

    Tarman, Paul B.

    Deregulation has caused a major change in power distribution in the USA. Large central power stations are being and will continue to be replaced by smaller, distributed power generation sources of less than 20 kW. Fuel cells, specifically molten carbonate fuel cells (MCFCs), are best suited to serve this need. Small turbines cannot achieve the efficiency or environmental friendliness of MCFCs in this power range. This paper discusses the goals of M-C Power Corporation and the advantages of its IMHEX® MCFC technology. M-C Power's factory, demonstration testing program, and its market-entry power plant are also described, as are its commercialization strategy and schedule.

  18. 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.

  19. Generative models for discovering sparse distributed representations.

    PubMed

    Hinton, G E; Ghahramani, Z

    1997-08-29

    We describe a hierarchical, generative model that can be viewed as a nonlinear generalization of factor analysis and can be implemented in a neural network. The model uses bottom-up, top-down and lateral connections to perform Bayesian perceptual inference correctly. Once perceptual inference has been performed the connection strengths can be updated using a very simple learning rule that only requires locally available information. We demonstrate that the network learns to extract sparse, distributed, hierarchical representations.

  20. Next generation tools for genomic data generation, distribution, and visualization.

    PubMed

    Nix, David A; Di Sera, Tonya L; Dalley, Brian K; Milash, Brett A; Cundick, Robert M; Quinn, Kevin S; Courdy, Samir J

    2010-09-09

    With the rapidly falling cost and availability of high throughput sequencing and microarray technologies, the bottleneck for effectively using genomic analysis in the laboratory and clinic is shifting to one of effectively managing, analyzing, and sharing genomic data. Here we present three open-source, platform independent, software tools for generating, analyzing, distributing, and visualizing genomic data. These include a next generation sequencing/microarray LIMS and analysis project center (GNomEx); an application for annotating and programmatically distributing genomic data using the community vetted DAS/2 data exchange protocol (GenoPub); and a standalone Java Swing application (GWrap) that makes cutting edge command line analysis tools available to those who prefer graphical user interfaces. Both GNomEx and GenoPub use the rich client Flex/Flash web browser interface to interact with Java classes and a relational database on a remote server. Both employ a public-private user-group security model enabling controlled distribution of patient and unpublished data alongside public resources. As such, they function as genomic data repositories that can be accessed manually or programmatically through DAS/2-enabled client applications such as the Integrated Genome Browser. These tools have gained wide use in our core facilities, research laboratories and clinics and are freely available for non-profit use. See http://sourceforge.net/projects/gnomex/, http://sourceforge.net/projects/genoviz/, and http://sourceforge.net/projects/useq.

  1. 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

  2. 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.

  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. Pseudoabsence generation strategies for species distribution models.

    PubMed

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

    2012-01-01

    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. 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. 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 density and area with predicted

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. Patterns of Nanoflare Heating Exhibited by Active Regions Observed with SDO/AIA

    NASA Astrophysics Data System (ADS)

    Viall, Nicholeen; Klimchuk, J.

    2011-05-01

    It seems largely agreed that many coronal loops---those observed at a temperature of about 1 MK---are bundles of unresolved strands that are heated by storms of impulsive nanoflares. The nature of coronal heating in hotter loops and in the very important but largely ignored diffuse component of active regions is much less clear. Are these regions also heated impulsively, or is the heating quasi steady? The spectacular new data from the Atmospheric Imaging Assembly (AIA) telescopes on the Solar Dynamics Observatory (SDO) offer an excellent opportunity to address this question. We analyze the light curves of coronal loops and the diffuse corona in 6 different AIA channels and compare them with the predicted light curves from theoretical models. Light curves in the different AIA channels reach their peak intensities with predictable orderings as a function of the nanoflare storm properties. These orderings, or time lags, are clearly exhibited in loop observations in all channels. What is especially exciting is that we identify these time lag patterns in observations of the seemingly steady diffuse corona as well. We model the diffuse corona as a line-of-sight integration of many thousands of completely independent, impulsively heated strands. The time lags of the simulated and actual observations are in excellent agreement. Our results suggest that impulsive nanoflare heating is ubiquitous within active regions. This research was supported through an appointment to the NASA Postdoctoral Program at the Goddard Space Flight Center, administered by Oak Ridge Associated Universities through a contract with NASA.

  15. NanoFlares for the detection, isolation, and culture of live tumor cells from human blood

    PubMed Central

    Halo, Tiffany L.; McMahon, Kaylin M.; Angeloni, Nicholas L.; Xu, Yilin; Wang, Wei; Chinen, Alyssa B.; Malin, Dmitry; Strekalova, Elena; Cryns, Vincent L.; Cheng, Chonghui; Mirkin, Chad A.; Thaxton, C. Shad

    2014-01-01

    Metastasis portends a poor prognosis for cancer patients. Primary tumor cells disseminate through the bloodstream before the appearance of detectable metastatic lesions. The analysis of cancer cells in blood—so-called circulating tumor cells (CTCs)—may provide unprecedented opportunities for metastatic risk assessment and investigation. NanoFlares are nanoconstructs that enable live-cell detection of intracellular mRNA. NanoFlares, when coupled with flow cytometry, can be used to fluorescently detect genetic markers of CTCs in the context of whole blood. They allow one to detect as few as 100 live cancer cells per mL of blood and subsequently culture those cells. This technique can also be used to detect CTCs in a murine model of metastatic breast cancer. As such, NanoFlares provide, to our knowledge, the first genetic-based approach for detecting, isolating, and characterizing live cancer cells from blood and may provide new opportunities for cancer diagnosis, prognosis, and personalized therapy. PMID:25404304

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Self-generated magnetic fields in q-distributed plasmas

    SciTech Connect

    Li Dingguo; Liu Sanqiu; Li Xiaoqing

    2013-02-15

    A quasi-steady magnetic field can be generated with high-frequency electromagnetic radiation through wave-wave and wave-particle interactions in astrophysical plasmas and laser-produced plasmas. Nonlinear coupling equations of self-generated magnetic fields are obtained in nonextensive distribution frame, as a generalization for the standard Maxwellian distribution frame. The numerical results show that self-generated magnetic fields may collapse and lead to various turbulent patterns with different index q.

  8. 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.

  9. Distributed generation for residential and small commercial markets

    SciTech Connect

    Ball, D.A.; Hanna, W.T.; Stets, J.A.

    1999-11-01

    Distributed generation offers two basic values: economics and the availability of standby power during grid outages. The first, economics, is related to the ability to generate electricity at or near the point of use and deliver it to the customer at lower cost than is possible through the grid. One way to do this is to take advantage of highly efficient cogeneration made possible by locating the generator near load centers. Another is to relieve grid congestion during high demand periods by operating behind power bottlenecks. Finally, distributed generators may offer the potential to achieve low installed cost with mass produced, small-scale, but highly efficient generators yielding low cost power. To realize the second value, standby power, a generator must be capable of grid independent operation. This requires black start capability and self-excitation of the generator. Since a distributed generator would seldom be sized to carry the entire site peak load, it also requires a transfer switch that allows selected critical circuits to be switched to the generator during standby operation such that they do not exceed the generator`s capability. This paper describes a particular approach to applying distributed generation in the residential marketplace. Small commercial establishments (such as small offices serving accountants, doctors, insurance agents etc.) are also included in that they closely resemble residential customers in extent and patterns of energy use.

  10. PATTERNS OF NANOFLARE STORM HEATING EXHIBITED BY AN ACTIVE REGION OBSERVED WITH SOLAR DYNAMICS OBSERVATORY/ATMOSPHERIC IMAGING ASSEMBLY

    SciTech Connect

    Viall, Nicholeen M.; Klimchuk, James A.

    2011-09-01

    It is largely agreed that many coronal loops-those observed at a temperature of about 1 MK-are bundles of unresolved strands that are heated by storms of impulsive nanoflares. The nature of coronal heating in hotter loops and in the very important but largely ignored diffuse component of active regions is much less clear. Are these regions also heated impulsively, or is the heating quasi-steady? The spectacular new data from the Atmospheric Imaging Assembly (AIA) telescopes on the Solar Dynamics Observatory offer an excellent opportunity to address this question. We analyze the light curves of coronal loops and the diffuse corona in six different AIA channels and compare them with the predicted light curves from theoretical models. Light curves in the different AIA channels reach their peak intensities with predictable orderings as a function the nanoflare storm properties. We show that while some sets of light curves exhibit clear evidence of cooling after nanoflare storms, other cases are less straightforward to interpret. Complications arise because of line-of-sight integration through many different structures, the broadband nature of the AIA channels, and because physical properties can change substantially depending on the magnitude of the energy release. Nevertheless, the light curves exhibit predictable and understandable patterns consistent with impulsive nanoflare heating.

  11. Competition and Cooperation of Distributed Generation and Power System

    NASA Astrophysics Data System (ADS)

    Miyake, Masatoshi; Nanahara, Toshiya

    Advances in distributed generation technologies together with the deregulation of an electric power industry can lead to a massive introduction of distributed generation. Since most of distributed generation will be interconnected to a power system, coordination and competition between distributed generators and large-scale power sources would be a vital issue in realizing a more desirable energy system in the future. This paper analyzes competitions between electric utilities and cogenerators from the viewpoints of economic and energy efficiency based on the simulation results on an energy system including a cogeneration system. First, we examine best response correspondence of an electric utility and a cogenerator with a noncooperative game approach: we obtain a Nash equilibrium point. Secondly, we examine the optimum strategy that attains the highest social surplus and the highest energy efficiency through global optimization.

  12. 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.

  13. Network-Oriented Approach to Distributed Generation Planning

    NASA Astrophysics Data System (ADS)

    Kochukov, O.; Mutule, A.

    2017-06-01

    The main objective of the paper is to present an innovative complex approach to distributed generation planning and show the advantages over existing methods. The approach will be most suitable for DNOs and authorities and has specific calculation targets to support the decision-making process. The method can be used for complex distribution networks with different arrangement and legal base.

  14. 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…

  15. 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…

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Load Frequency Control in Power System with Distributed Generation

    NASA Astrophysics Data System (ADS)

    Yukita, Kazuto; Ota, Takuya; Fujimoto, Koji; Goto, Yasuyuki; Ichiyanagi, Katuhiro

    This paper proposes a method to improve the load frequency control in a power system with distributed generation (DG). DG is assumed to include photovoltaic generation, wind power generation, fuel cells and etc. In this paper, a simulation is performed using a microgrid model or island model that is composed of a storage system with either wind power generation or photovoltaic generation system as the DG. The effectiveness of load frequency control (LFC) using a storage system is examined using a power transmission simulator. The model for the experiment has been composed of inverter, battery, synchronous generator and load. Using this model, the comparison examination was done in respect of output setting control and the case in which the PI control was used. As a result, when the output set-point control using power demand estimation method is executed, the control characteristic is very excellent.

  3. Generation of distributed W-states over long distances

    NASA Astrophysics Data System (ADS)

    Li, Yi

    2017-08-01

    Ultra-secure quantum communication between distant locations requires distributed entangled states between nodes. Various methodologies have been proposed to tackle this technological challenge, of which the so-called DLCZ protocol is the most promising and widely adopted scheme. This paper aims to extend this well-known protocol to a multi-node setting where the entangled W-state is generated between nodes over long distances. The generation of multipartite W-states is the foundation of quantum networks, paving the way for quantum communication and distributed quantum computation.

  4. 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.

  5. 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.

  6. Distributed generation: Residential storage comes at a cost

    NASA Astrophysics Data System (ADS)

    Hittinger, Eric

    2017-01-01

    The combined effect of increased variability of demand due to distributed generation and domestic storage deployment represents a new feature in modern electricity systems. A recent study shows that while storage can reduce peak demand, it could also increase overall consumption and electricity system emissions.

  7. 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.

  8. 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.”

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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%).

  6. 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.

  7. 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.

  8. 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.

  9. Microscale air quality impacts of distributed power generation facilities.

    PubMed

    Olaguer, Eduardo P; Knipping, Eladio; Shaw, Stephanie; Ravindran, Satish

    2016-08-01

    The electric system is experiencing rapid growth in the adoption of a mix of distributed renewable and fossil fuel sources, along with increasing amounts of off-grid generation. New operational regimes may have unforeseen consequences for air quality. A three-dimensional microscale chemical transport model (CTM) driven by an urban wind model was used to assess gaseous air pollutant and particulate matter (PM) impacts within ~10 km of fossil-fueled distributed power generation (DG) facilities during the early afternoon of a typical summer day in Houston, TX. Three types of DG scenarios were considered in the presence of motor vehicle emissions and a realistic urban canopy: (1) a 25-MW natural gas turbine operating at steady state in either simple cycle or combined heating and power (CHP) mode; (2) a 25-MW simple cycle gas turbine undergoing a cold startup with either moderate or enhanced formaldehyde emissions; and (3) a data center generating 10 MW of emergency power with either diesel or natural gas-fired backup generators (BUGs) without pollution controls. Simulations of criteria pollutants (NO2, CO, O3, PM) and the toxic pollutant, formaldehyde (HCHO), were conducted assuming a 2-hr operational time period. In all cases, NOx titration dominated ozone production near the source. The turbine scenarios did not result in ambient concentration enhancements significantly exceeding 1 ppbv for gaseous pollutants or over 1 µg/m(3) for PM after 2 hr of emission, assuming realistic plume rise. In the case of the datacenter with diesel BUGs, ambient NO2 concentrations were enhanced by 10-50 ppbv within 2 km downwind of the source, while maximum PM impacts in the immediate vicinity of the datacenter were less than 5 µg/m(3). Plausible scenarios of distributed fossil generation consistent with the electricity grid's transformation to a more flexible and modernized system suggest that a substantial amount of deployment would be required to significantly affect air quality on

  10. 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.

  11. 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.

  12. 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.

  13. Interconnecting Single-Phase Generation to the Utility Distribution System

    SciTech Connect

    Dugan, R.C.

    2001-12-05

    One potentially large source of underutilized distributed generation (DG) capacity exists in single-phase standby backup gensets on farms served from single-phase feeder laterals. Utilizing the excess capacity would require interconnecting to the utility system. Connecting single-phase gensets to the utility system presents some interesting technical issues that have not been previously investigated. This paper addresses several of the interconnection issues associated with this form of DG including voltage regulation, harmonics, overcurrent protection, and islanding. A significant amount of single-phase DG can be accommodated by the utility distribution system, but there are definite limitations due to the nature and location of the DG. These limitations may be more restrictive than is commonly assumed for three-phase DG installed on stronger parts of the electric distribution system.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Random generation of RNA secondary structures according to native distributions.

    PubMed

    Nebel, Markus E; Scheid, Anika; Weinberg, Frank

    2011-10-12

    Random biological sequences are a topic of great interest in genome analysis since, according to a powerful paradigm, they represent the background noise from which the actual biological information must differentiate. Accordingly, the generation of random sequences has been investigated for a long time. Similarly, random object of a more complicated structure like RNA molecules or proteins are of interest. In this article, we present a new general framework for deriving algorithms for the non-uniform random generation of combinatorial objects according to the encoding and probability distribution implied by a stochastic context-free grammar. Briefly, the framework extends on the well-known recursive method for (uniform) random generation and uses the popular framework of admissible specifications of combinatorial classes, introducing weighted combinatorial classes to allow for the non-uniform generation by means of unranking. This framework is used to derive an algorithm for the generation of RNA secondary structures of a given fixed size. We address the random generation of these structures according to a realistic distribution obtained from real-life data by using a very detailed context-free grammar (that models the class of RNA secondary structures by distinguishing between all known motifs in RNA structure). Compared to well-known sampling approaches used in several structure prediction tools (such as SFold) ours has two major advantages: Firstly, after a preprocessing step in time O(n2) for the computation of all weighted class sizes needed, with our approach a set of m random secondary structures of a given structure size n can be computed in worst-case time complexity Om⋅n⋅ log(n) while other algorithms typically have a runtime in O(m⋅n2). Secondly, our approach works with integer arithmetic only which is faster and saves us from all the discomforting details of using floating point arithmetic with logarithmized probabilities. A number of

  19. Random generation of RNA secondary structures according to native distributions

    PubMed Central

    2011-01-01

    Background Random biological sequences are a topic of great interest in genome analysis since, according to a powerful paradigm, they represent the background noise from which the actual biological information must differentiate. Accordingly, the generation of random sequences has been investigated for a long time. Similarly, random object of a more complicated structure like RNA molecules or proteins are of interest. Results In this article, we present a new general framework for deriving algorithms for the non-uniform random generation of combinatorial objects according to the encoding and probability distribution implied by a stochastic context-free grammar. Briefly, the framework extends on the well-known recursive method for (uniform) random generation and uses the popular framework of admissible specifications of combinatorial classes, introducing weighted combinatorial classes to allow for the non-uniform generation by means of unranking. This framework is used to derive an algorithm for the generation of RNA secondary structures of a given fixed size. We address the random generation of these structures according to a realistic distribution obtained from real-life data by using a very detailed context-free grammar (that models the class of RNA secondary structures by distinguishing between all known motifs in RNA structure). Compared to well-known sampling approaches used in several structure prediction tools (such as SFold) ours has two major advantages: Firstly, after a preprocessing step in time O(n2) for the computation of all weighted class sizes needed, with our approach a set of m random secondary structures of a given structure size n can be computed in worst-case time complexity Om⋅n⋅ log(n) while other algorithms typically have a runtime in O(m⋅n2). Secondly, our approach works with integer arithmetic only which is faster and saves us from all the discomforting details of using floating point arithmetic with logarithmized probabilities

  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. 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

  3. 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.

  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; 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

  6. 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.

  7. 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.

  8. Generation of Weibull distribution clutter based on correlated Gaussian sequence

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Xin, Fengming

    2017-08-01

    With the continuous development of science and technology, the electromagnetic environment becomes more complex. Accurate clutter modeling is becoming increasingly difficult, which will have adverse effects in echo analysis. In this paper, in order to overcome electromagnetic interference, we use correlated Gaussian sequence to generate Weibull distribution clutter. Simulation results show that the estimated value of the proposed method is close to the theoretical value in the aspect of probability density and power spectral density. That demonstrates the validity of our method. Finally, the conclusions are given.

  9. Performance of finite order distribution-generated universal portfolios

    NASA Astrophysics Data System (ADS)

    Pang, Sook Theng; Liew, How Hui; Chang, Yun Fah

    2017-04-01

    A Constant Rebalanced Portfolio (CRP) is an investment strategy which reinvests by redistributing wealth equally among a set of stocks. The empirical performance of the distribution-generated universal portfolio strategies are analysed experimentally concerning 10 higher volume stocks from different categories in Kuala Lumpur Stock Exchange. The time interval of study is from January 2000 to December 2015, which includes the credit crisis from September 2008 to March 2009. The performance of the finite-order universal portfolio strategies has been shown to be better than Constant Rebalanced Portfolio with some selected parameters of proposed universal portfolios.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. 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...

  18. 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...

  19. 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...

  20. 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.

  1. Generating Distributed Forcing Fields for Spatial Hydrologic Modeling

    NASA Astrophysics Data System (ADS)

    Nayak, A.; Marks, D.; Chandler, D.; Winstral, A.

    2006-12-01

    Spatial hydrologic modeling requires the development of distributed forcing fields of weather and precipitation. This is particularly difficult in mountainous regions of the western US, where measurement sites are limited and the landscape is dominated by complex terrain and variations in vegetation cover. The Reynolds Creek Experimental Watershed (RCEW), in southwestern Idaho offers a unique opportunity to evaluate the sensitivity of interpolation techniques to the number and location of measurement sites. The RCEW, a 239 km2 hydro-climatic observatory operated by the USDA Agricultural Research Service since the early 1960's, contains 36 hydro-climatic measurement sites for monitoring the range of weather, snow and precipitation conditions across this complex mountain watershed. The MicroMet weather distribution utility, a process and topographically based weather interpolation tool (Liston and Elder, 2006), is used to generate surfaces of temperature, humidity, wind and precipitation over the snow-dominated 55 km2 (elevation range1398-2244m) Tollgate sub-catchment of RCEW. Nineteen meteorological stations were used to simulate the distribution of weather and precipitation for a series of storms during the 2004 water year. Measured and simulated values were compared to evaluate the accuracy of the model, and a jackknife approach was used to evaluate its sensitivity to data from particular stations. To evaluate the effect of elevation and storm track, different combinations of stations were selected, and to evaluate topographic exposure and vegetation shelter stations were divided into groups based on wind exposure. Results show that, even using a sophisticated weather distribution utility like MicroMet, the interpolation is very sensitive to station location and wind exposure. A certain amount of smoothing occurs even when using all 19 stations, but significant differences occur if only protected sites (similar to NRCS Snotel sites), or only wind-exposed sites are

  2. The Effect of Distributed Energy Resource Competition with Central Generation

    SciTech Connect

    Hadley, SW

    2003-12-10

    Distributed Energy Resource (DER) has been touted as a clean and efficient way to generate electricity at end-use sites, potentially allowing the exhaust heat to be put to good use as well. However, despite its environmental acceptability compared to many other types of generation, it has faced some disapproval because it may displace other, cleaner generation technologies. The end result could be more pollution than if the DER were not deployed. On the other hand, the DER may be competing against older power plants. If the DER is built then these other plants may be retired sooner, reducing their emissions. Or it may be that DER does not directly compete against either new or old plant capacity at the decision-maker level, and increased DER simply reduces the amount of time various plants operate. The key factor is what gets displaced if DER is added. For every kWh made by DER a kWh (or more with losses) of other production is not made. If enough DER is created, some power plants will get retired or not get built so not only their production but their capacity is displaced. Various characteristics of the power system in a region will influence how DER impacts the operation of the grid. The growth in demand in the region may influence whether new plants are postponed or old plants retired. The generation mix, including the fuel types, efficiencies, and emission characteristics of the plants in the region will factor into the overall competition. And public policies such as ease of new construction, emissions regulations, and fuel availability will also come into consideration.

  3. 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.

  4. 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

  5. Performance Enhancement of Radial Distributed System with Distributed Generators by Reconfiguration Using Binary Firefly Algorithm

    NASA Astrophysics Data System (ADS)

    Rajalakshmi, N.; Padma Subramanian, D.; Thamizhavel, K.

    2015-03-01

    The extent of real power loss and voltage deviation associated with overloaded feeders in radial distribution system can be reduced by reconfiguration. Reconfiguration is normally achieved by changing the open/closed state of tie/sectionalizing switches. Finding optimal switch combination is a complicated problem as there are many switching combinations possible in a distribution system. Hence optimization techniques are finding greater importance in reducing the complexity of reconfiguration problem. This paper presents the application of firefly algorithm (FA) for optimal reconfiguration of radial distribution system with distributed generators (DG). The algorithm is tested on IEEE 33 bus system installed with DGs and the results are compared with binary genetic algorithm. It is found that binary FA is more effective than binary genetic algorithm in achieving real power loss reduction and improving voltage profile and hence enhancing the performance of radial distribution system. Results are found to be optimum when DGs are added to the test system, which proved the impact of DGs on distribution system.

  6. Enhanced distribution of fourth-generation fluoroquinolones in prostatic tissue.

    PubMed

    Perletti, G; Wagenlehner, F M E; Naber, K G; Magri, V

    2009-03-01

    A recently published pharmacokinetic trial showed that the fluoroquinolone moxifloxacin administered to healthy volunteers at the single oral dose of 400mg accumulates in prostatic secretions (PS) up to a median concentration of 3.99 mg/L and reaches a PS/plasma concentration ratio of 1.57, far higher than values shown by other fluoroquinolones such as norfloxacin (ratio 0.1) or ciprofloxacin (ratio 0.2). Ion trapping mechanisms were hypothesised to be among the determinants of this effect. However, whether ion trapping would solely account for the observed differences in fluoroquinolone pharmacokinetics was left to further research and discussion. In this hypothesis paper, we review various published evidence on the tissue distribution of moxifloxacin and other quinolones, suggesting that increased lipophilicity, binding to cellular matrices and fast cellular uptake/release kinetics may be mechanisms compatible with enhanced prostatic accumulation and secretion of fourth-generation fluoroquinolones.

  7. Dust generation in powders: Effect of particle size distribution

    NASA Astrophysics Data System (ADS)

    Chakravarty, Somik; Le Bihan, Olivier; Fischer, Marc; Morgeneyer, Martin

    2017-06-01

    This study explores the relationship between the bulk and grain-scale properties of powders and dust generation. A vortex shaker dustiness tester was used to evaluate 8 calcium carbonate test powders with median particle sizes ranging from 2μm to 136μm. Respirable aerosols released from the powder samples were characterised by their particle number and mass concentrations. All the powder samples were found to release respirable fractions of dust particles which end up decreasing with time. The variation of powder dustiness as a function of the particle size distribution was analysed for the powders, which were classified into three groups based on the fraction of particles within the respirable range. The trends we observe might be due to the interplay of several mechanisms like de-agglomeration and attrition and their relative importance.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. Distributed generation capabilities of the national energy modeling system

    SciTech Connect

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

    2003-01-01

    This report describes Berkeley Lab's exploration of how the National Energy Modeling System (NEMS) models distributed generation (DG) and presents possible approaches for improving how DG is modeled. The on-site electric generation capability has been available since the AEO2000 version of NEMS. Berkeley Lab has previously completed research on distributed energy resources (DER) adoption at individual sites and has developed a DER Customer Adoption Model called DER-CAM. Given interest in this area, Berkeley Lab set out to understand how NEMS models small-scale on-site generation to assess how adequately DG is treated in NEMS, and to propose improvements or alternatives. The goal is to determine how well NEMS models the factors influencing DG adoption and to consider alternatives to the current approach. Most small-scale DG adoption takes place in the residential and commercial modules of NEMS. Investment in DG ultimately offsets purchases of electricity, which also eliminates the losses associated with transmission and distribution (T&D). If the DG technology that is chosen is photovoltaics (PV), NEMS assumes renewable energy consumption replaces the energy input to electric generators. If the DG technology is fuel consuming, consumption of fuel in the electric utility sector is replaced by residential or commercial fuel consumption. The waste heat generated from thermal technologies can be used to offset the water heating and space heating energy uses, but there is no thermally activated cooling capability. This study consists of a review of model documentation and a paper by EIA staff, a series of sensitivity runs performed by Berkeley Lab that exercise selected DG parameters in the AEO2002 version of NEMS, and a scoping effort of possible enhancements and alternatives to NEMS current DG capabilities. In general, the treatment of DG in NEMS is rudimentary. The penetration of DG is determined by an economic cash-flow analysis that determines adoption based on the

  13. 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.

  14. 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.

  15. 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.

    2017-06-01

    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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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

  1. 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.

  2. 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 ...

  3. 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 ...

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. Fuel cell power plants in a distributed generator application

    SciTech Connect

    Smith, M.J.

    1996-12-31

    ONSI`s (a subsidiary of International Fuel Cells Corporation) world wide fleet of 200-kW PC25{trademark} phosphoric acid fuel cell power plants which began operation early in 1992 has shown excellent performance and reliability in over 1 million hours of operation. This experience has verified the clean, quiet, reliable operation of the PC25 and confirmed its application as a distributed generator. Continuing product development efforts have resulted in a one third reduction of weight and volume as well as improved installation and operating characteristics for the PC25 C model. Delivery of this unit began in 1995. International Fuel Cells (IFC) continues its efforts to improve product design and manufacturing processes. This progress has been sustained at a compounded rate of 10 percent per year since the late 1980`s. These improvements will permit further reductions in the initial cost of the power plant and place increased emphasis on market development as the pacing item in achieving business benefits from the PC25 fuel cell. Derivative product opportunities are evolving with maturation of the technologies in a commercial environment. The recent announcement of Praxair, Inc., and IFC introducing a non-cryogenic hydrogen supply system utilizing IFC`s steam reformer is an example. 11 figs.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 29 CFR 1910.269 - Electric power generation, transmission, and distribution.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 5 2011-07-01 2011-07-01 false Electric power generation, transmission, and distribution... § 1910.269 Electric power generation, transmission, and distribution. Note: OSHA is staying the... the operation and maintenance of electric power generation, control, transformation, transmission, and...

  15. 29 CFR 1910.269 - Electric power generation, transmission, and distribution.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Electric power generation, transmission, and distribution... § 1910.269 Electric power generation, transmission, and distribution. Note: OSHA is staying the... the operation and maintenance of electric power generation, control, transformation, transmission, and...

  16. Solar Photovoltaic (PV) Distributed Generation Systems - Control and Protection

    NASA Astrophysics Data System (ADS)

    Yi, Zhehan

    This dissertation proposes a comprehensive control, power management, and fault detection strategy for solar photovoltaic (PV) distribution generations. Battery storages are typically employed in PV systems to mitigate the power fluctuation caused by unstable solar irradiance. With AC and DC loads, a PV-battery system can be treated as a hybrid microgrid which contains both DC and AC power resources and buses. In this thesis, a control power and management system (CAPMS) for PV-battery hybrid microgrid is proposed, which provides 1) the DC and AC bus voltage and AC frequency regulating scheme and controllers designed to track set points; 2) a power flow management strategy in the hybrid microgrid to achieve system generation and demand balance in both grid-connected and islanded modes; 3) smooth transition control during grid reconnection by frequency and phase synchronization control between the main grid and microgrid. Due to the increasing demands for PV power, scales of PV systems are getting larger and fault detection in PV arrays becomes challenging. High-impedance faults, low-mismatch faults, and faults occurred in low irradiance conditions tend to be hidden due to low fault currents, particularly, when a PV maximum power point tracking (MPPT) algorithm is in-service. If remain undetected, these faults can considerably lower the output energy of solar systems, damage the panels, and potentially cause fire hazards. In this dissertation, fault detection challenges in PV arrays are analyzed in depth, considering the crossing relations among the characteristics of PV, interactions with MPPT algorithms, and the nature of solar irradiance. Two fault detection schemes are then designed as attempts to address these technical issues, which detect faults inside PV arrays accurately even under challenging circumstances, e.g., faults in low irradiance conditions or high-impedance faults. Taking advantage of multi-resolution signal decomposition (MSD), a powerful signal

  17. 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

  18. Optimization based on benefit of regional energy suppliers of distributed generation in active distribution network

    NASA Astrophysics Data System (ADS)

    Huo, Xianxu; Li, Guodong; Jiang, Ling; Wang, Xudong

    2017-08-01

    With the development of electricity market, distributed generation (DG) technology and related policies, regional energy suppliers are encouraged to build DG. Under this background, the concept of active distribution network (ADN) is put forward. In this paper, a bi-level model of intermittent DG considering benefit of regional energy suppliers is proposed. The objective of the upper level is the maximization of benefit of regional energy suppliers. On this basis, the lower level is optimized for each scene. The uncertainties of DG output and load of users, as well as four active management measures, which include demand-side management, curtailing the output power of DG, regulating reactive power compensation capacity and regulating the on-load tap changer, are considered. Harmony search algorithm and particle swarm optimization are combined as a hybrid strategy to solve the model. This model and strategy are tested with IEEE-33 node system, and results of case study indicate that the model and strategy successfully increase the capacity of DG and benefit of regional energy suppliers.

  19. Automatic distributed workflow generation with GridMD library

    NASA Astrophysics Data System (ADS)

    Morozov, I. V.; Valuev, I. A.

    2011-09-01

    GridMD is a C++ class library intended for constructing simulation applications and running them in distributed environments. The library abstracts away from details of distributed environments, so that almost no knowledge of distributed computing is required from a physicist working with the library. She or he just uses GridMD function calls inside the application C++ code to perform parameter sweeps or other tasks that can be distributed at run-time. In this paper we briefly review the GridMD architecture. We also describe the job manager component which submits jobs to a remote system. The C++ source code of our PBS job manager may be used as a standalone tool and it is freely available as well as the full library source code. As illustrative examples we use simple expression evaluation codes and the real application of Coulomb cluster explosion simulation by Molecular Dynamics.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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

  5. 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

  6. Three-phase Unbalanced Interval Power Flow Calculation of Low-voltage Distribution Network with Distributed PV Power Generation

    NASA Astrophysics Data System (ADS)

    Yuan, Yan; Shunjiang, Lin; Yuan, Lu

    2017-05-01

    Low-voltage distribution network is a three-phase unbalanced system due to the integration of single-phase loads and single-phase distributed PV arrays. In this paper, three-phase unbalanced interval power flow calculation model of three-phase four-wire low voltage distribution network with distributed PV power generation is established. In the model, intensity of illumination and battery temperature which influence the power output of distributed PV power generation is described as intervals. Then, through the affine interval algorithm, the interval power flow problem is transformed into a deterministic power flow problem and two linear optimization problems. By solving the above problems, the interval power flow solution can be obtained. Finally, the proposed algorithm is applied to an actual 22-bus low-voltage distribution network, and the solution of the affine interval algorithm is compared to the solution of the Monte Carlo sampling method, which verifies the correctness and effectiveness of the proposed algorithm.

  7. 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.

  8. The Distribution of Active Force Generators Controls Mitotic Spindle Position

    NASA Astrophysics Data System (ADS)

    Grill, Stephan W.; Howard, Jonathon; Schäffer, Erik; Stelzer, Ernst H. K.; Hyman, Anthony A.

    2003-07-01

    During unequal cell divisions a mitotic spindle is eccentrically positioned before cell cleavage. To determine the basis of the net force imbalance that causes spindle displacement in one-cell Caenorhabditis elegans embryos, we fragmented centrosomes with an ultraviolet laser. Analysis of the mean and variance of fragment speeds suggests that the force imbalance is due to a larger number of force generators pulling on astral microtubules of the posterior aster relative to the anterior aster. Moreover, activation of heterotrimeric guanine nucleotide-binding protein (G protein) α subunits is required to generate these astral forces.

  9. 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.

  10. 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.

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

    DTIC Science & Technology

    2009-03-01

    Afghanistan have presented significant civil infrastructure rebuilding challenges to these nations, as well as to the United States, coalition allies, and...presented significant civil infrastructure rebuilding challenges to these nations, as well as to the United States, coalition allies, and the United...10 II. DISTRIBUTED GENERATION AND MICROGRIDS ........................................11 A. DISTRIBUTED GENERATION DEFINED

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Next-Generation Undersea Warfare and Undersea Distributed Networked Systems

    DTIC Science & Technology

    2007-01-31

    ACRONYMS AlP Air-independent propulsion AOU Area of uncertainty ASCM Antiship cruise missile ASDS Advanced Swimmer Delivery System ASUW Antisurface warfare... maritime commons who may or may not have weapons of mass destruction .4, The 2006 Quadrennial Defense Review6 lays out the force planning construct for...Joint maritime forces, including the Coast Guard, will conduct highly distributed operations with a networked fleet that is more capable of projecting

  19. 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.

  20. Drilling in bone: modeling heat generation and temperature distribution.

    PubMed

    Davidson, Sean R; James, David F

    2003-06-01

    Thermo-mechanical equations were developed from machining theory to predict heat generation due to drilling and were coupled with a heat transfer FEM simulation to predict the temperature rise and thermal injury in bone during a drilling operation. The rotational speed, feed rate, drill geometry and bone material properties were varied in a parametric analysis to determine the importance of each on temperature rise and therefore on thermal damage. It was found that drill speed, feed rate and drill diameter had the most significant thermal impact while changes in drill helix angle, point angle and bone thermal properties had relatively little effect.

  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. Freezing Directed Construction of Bio/Nano Interfaces: Reagentless Conjugation, Denser Spherical Nucleic Acids, and Better Nanoflares.

    PubMed

    Liu, Biwu; Liu, Juewen

    2017-07-19

    While nanoparticle solutions cannot freeze in general, they may remain stable in the presence of polymer stabilizers. We herein communicate that gold nanoparticles (AuNPs) are stable in the presence of thiolated DNA after a freeze-thaw cycle. The DNA is conjugated to AuNPs during freezing without additional reagents and the conjugation can be completed in a few minutes. More importantly, the DNA density is 20-30% higher than that prepared by the typical salt-aging method. By lowering temperature, DNA hybridization is also promoted, allowing the construction of better nanoflares with doubled probe density and signaling sensitivity. This freezing method works for AuNPs from 5 to 100 nm and all tested DNA sequences. The mechanism was studied by separating the effect of temperature, freezing and thawing, where the exclusion of salt and AuNPs by the growing ice crystals is deemed critical. In addition to developing a simple method, this study articulates unique physical processes during freezing with important fundamental surface science implications, and it could be extended to other systems.

  5. 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.

  6. 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.

  7. 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.

  8. Aircraft generation and distribution systems; Proceedings of the Conference, London, United Kingdom, Oct. 14, 1992

    NASA Astrophysics Data System (ADS)

    The papers presented in this volume provide an overview of recent developments in aircraft electric power generation and distribution systems. In particular, attention is given to airline requirements on aircraft electrical power generation and distribution, matching today's technology to the electric power requirements, and flexible alternatives to constant frequency systems. Papers are also presented on load management, solid state relays, and the Boeing 777 electrical system.

  9. 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.

  10. 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.

  11. 29 CFR 1910.269 - Electric power generation, transmission, and distribution.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 5 2014-07-01 2014-07-01 false Electric power generation, transmission, and distribution. 1910.269 Section 1910.269 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH STANDARDS Special Industries § 1910.269 Electric power generation,...

  12. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species

    Treesearch

    Keith B. Aubry; Catherine M. Raley; Kevin S. McKelvey

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated...

  13. Exploring changes in the spatial distribution of stream baseflow generation during a seasonal recession

    Treesearch

    R.A. Payn; M.N. Gooseff; B.L. McGlynn; K.E. Bencala; S.M. Wondzell

    2012-01-01

    Relating watershed structure to streamflow generation is a primary focus of hydrology. However, comparisons of longitudinal variability in stream discharge with adjacent valley structure have been rare, resulting in poor understanding of the distribution of the hydrologic mechanisms that cause variability in streamflow generation along valleys. This study explores...

  14. Size Distribution and Rate of Dust Generated During Grain Elevator Handling

    USDA-ARS?s Scientific Manuscript database

    Dust generated during grain handling is an air pollutant that produces safety and health hazards. This study was conducted to characterize the particle size distribution (PSD) of dust generated during handling of wheat and shelled corn in the research elevator of the USDA Grain Marketing and Product...

  15. 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.

  16. A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

    NASA Astrophysics Data System (ADS)

    Maurer, T.; Schneider, A.; Gerke, H. H.

    2011-05-01

    Artificially-created hydrological catchments are characterized by sediment structures from technological construction processes that can potentially be important for modelling of flow and transport and for understanding initial soil and ecosystem development. The subsurface spatial structures of such catchments have not yet been sufficiently explored and described. Our objective was to develop a structure generator programme for modelling the 3-D spatial sediment distribution patterns depending on the technical earth-moving and deposition processes. For the development, the artificially-constructed hydrological catchment "Chicken Creek" located in Lower Lusatia, Germany, served as an example. The structure generator describes 3-D technological sediment distributions at two scales: (i) for a 2-D-vertical cross-section, texture and bulk density distributions are generated within individual spoil cones that result from mass dumping, particle segregation, and compaction and (ii) for the whole catchment area, the spoil cones are horizontally arranged along trajectories of mass dumping controlled by the belt stacker-machine relative to the catchment's clay layer topography. The generated 3-D texture and bulk density distributions are interpolated and visualized as a gridded 3-D-volume body using 3-D computer-aided design software. The generated subsurface sediment distribution for the Chicken Creek catchment was found to correspond to observed patterns although still without any calibration. Spatial aggregation and interpolation in the gridded volume body modified the generated distributions towards more uniform (unimodal) distributions and lower values of the standard deviations. After incorporating variations and pedotransfer approaches, generated sediment distributions can be used for deriving realizations of the 3-D hydraulic catchment structure.

  17. 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.

  18. Determination of optimum allocation and pricing of distributed generation using genetic algorithm methodology

    NASA Astrophysics Data System (ADS)

    Mwakabuta, Ndaga Stanslaus

    Electric power distribution systems play a significant role in providing continuous and "quality" electrical energy to different classes of customers. In the context of the present restrictions on transmission system expansions and the new paradigm of "open and shared" infrastructure, new approaches to distribution system analyses, economic and operational decision-making need investigation. This dissertation includes three layers of distribution system investigations. In the basic level, improved linear models are shown to offer significant advantages over previous models for advanced analysis. In the intermediate level, the improved model is applied to solve the traditional problem of operating cost minimization using capacitors and voltage regulators. In the advanced level, an artificial intelligence technique is applied to minimize cost under Distributed Generation injection from private vendors. Soft computing techniques are finding increasing applications in solving optimization problems in large and complex practical systems. The dissertation focuses on Genetic Algorithm for investigating the economic aspects of distributed generation penetration without compromising the operational security of the distribution system. The work presents a methodology for determining the optimal pricing of distributed generation that would help utilities make a decision on how to operate their system economically. This would enable modular and flexible investments that have real benefits to the electric distribution system. Improved reliability for both customers and the distribution system in general, reduced environmental impacts, increased efficiency of energy use, and reduced costs of energy services are some advantages.

  19. 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.

  20. 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.

  1. Calculation of reflectance distribution using angular spectrum convolution in mesh-based computer generated hologram.

    PubMed

    Yeom, Han-Ju; Park, Jae-Hyeung

    2016-08-22

    We propose a method to obtain a computer-generated hologram that renders reflectance distributions of individual mesh surfaces of three-dimensional objects. Unlike previous methods which find phase distribution inside each mesh, the proposed method performs convolution of angular spectrum of the mesh to obtain desired reflectance distribution. Manipulation in the angular spectrum domain enables its application to fully-analytic mesh based computer generated hologram, removing the necessity for resampling of the spatial frequency grid. It is also computationally inexpensive as the convolution can be performed efficiently using Fourier transform. In this paper, we present principle, error analysis, simulation, and experimental verification results of the proposed method.

  2. A structure generator for modelling the initial sediment distribution of an artificial hydrologic catchment

    NASA Astrophysics Data System (ADS)

    Maurer, T.; Schneider, A.; Gerke, H. H.

    2011-12-01

    Artificially-created hydrological catchments are characterised by sediment structures from technological construction processes that can potentially be important for modelling of flow and transport and for understanding initial soil and ecosystem development. The subsurface spatial structures of such catchments have not yet been sufficiently explored and described. Our objective was to develop a structure generator programme for modelling the 3-D spatial distribution patterns of dumped sediments depending on the technical earth-moving and deposition processes. We are focussing in a first step on integrating sediment dumping, particle size, and bulk density modification processes on the catchment scale. For the model development, the artificially-constructed hydrological catchment "Chicken Creek" located in Lower Lusatia, Germany, served as an example. The structure generator describes 3-D technological sediment distributions at two scales: (i) for a 2-D-vertical cross-section, texture and bulk density distributions are generated within individual spoil cones that result from mass dumping, particle segregation, and compaction and (ii) for the whole catchment, the spoil cones are horizontally arranged along trajectories of mass dumping controlled by the belt stacker-machine relative to the catchment's clay layer topography. The generated 3-D texture and bulk density distributions are interpolated and visualised as a gridded 3-D-volume body using 3-D computer-aided design software. The generated subsurface sediment distribution for the Chicken Creek catchment was found to correspond to observed patterns already without calibration. Spatial aggregation and interpolation in the gridded volume body modified the generated distributions towards more uniform (unimodal) distributions and lower values of the standard deviations. The modelling approach is generally applicable to all situations where large masses of unconsolidated sediment are moved and dumped thereby allowing

  3. Transverse momentum dependent (TMD) parton distribution functions generated in the modified DGLAP formalism based on the valence-like distributions

    NASA Astrophysics Data System (ADS)

    Hosseinkhani, H.; Modarres, M.; Olanj, N.

    2017-07-01

    Transverse momentum dependent (TMD) parton distributions, also referred to as unintegrated parton distribution functions (UPDFs), are produced via the Kimber-Martin-Ryskin (KMR) prescription. The GJR08 set of parton distribution functions (PDFs) which are based on the valence-like distributions is used, at the leading order (LO) and the next-to-leading order (NLO) approximations, as inputs of the KMR formalism. The general and the relative behaviors of the generated TMD PDFs at LO and NLO and their ratios in a wide range of the transverse momentum values, i.e. kt2 = 10, 102, 104 and 108GeV2 are investigated. It is shown that the properties of the parent valence-like PDFs are imprinted on the daughter TMD PDFs. Imposing the angular ordering constraint (AOC) leads to the dynamical variable limits on the integrals which in turn increase the contributions from the lower scales at lower kt2. The results are compared with our previous studies based on the MSTW2008 input PDFs and it is shown that the present calculation gives flatter TMD PDFs. Finally, a comparison of longitudinal structure function (FL) is made by using the produced TMD PDFs and those that were generated through the MSTW2008-LO PDF from our previous work and the corresponding data from H1 and ZEUS collaborations and a reasonable agreement is found.

  4. 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.

  5. Effect of ultrasonic frequency on size distributions of nanosized mist generated by ultrasonic atomization.

    PubMed

    Kudo, Takahisa; Sekiguchi, Kazuhiko; Sankoda, Kenshi; Namiki, Norikazu; Nii, Susumu

    2017-07-01

    Ultrasonic atomization is used to produce fine liquid mists with diameter ranges below 100nm. We investigated the effect of the frequency on the size distribution of ultrasonic mist. A bimodal distribution was obtained for the mist generated by ultrasonic atomization with a wide-range particle spectrometer. The peak diameter decreased with increasing frequency, and the number concentration of the mist increased in the smaller range. We determined the relation between the size distribution of the mist and the ultrasonic frequency, and we proposed a generation mechanism for the ultrasonic nanosized mist based on the amount of water vapor around the liquid column. Increasing the power intensity and density by changing the surface diameter of the ultrasonic oscillator affected the number concentration and size distribution of the nanosized mist. Using this technique, the diameter of the mist can be controlled by changing the frequency of the ultrasonic transducer. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. 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].

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

    2017-04-01

    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.

  13. 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.

  14. 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.

  15. 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

  16. Generation effects on the microstructure and product distribution in ethylene polymerization promoted by dendritic nickel catalysts.

    PubMed

    Benito, José M; de Jesús, Ernesto; de la Mata, F Javier; Flores, Juan C; Gómez, Rafael

    2005-11-07

    Carbosilane dendrimers Gn-[(ONNMe2)NiBr2]m, containing up to sixteen terminal pyridylimine nickel complexes, have been studied as catalysts for polymerization of ethylene; the microstructure and the oligomer/polymer distribution are significantly affected by the generation of the dendritic precursor.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. A distributed parameter model of transmission line transformer for high voltage nanosecond pulse generation

    NASA Astrophysics Data System (ADS)

    Li, Jiangtao; Zhao, Zheng; Li, Longjie; He, Jiaxin; Li, Chenjie; Wang, Yifeng; Su, Can

    2017-09-01

    A transmission line transformer has potential advantages for nanosecond pulse generation including excellent frequency response and no leakage inductance. The wave propagation process in a secondary mode line is indispensable due to an obvious inside transient electromagnetic transition in this scenario. The equivalent model of the transmission line transformer is crucial for predicting the output waveform and evaluating the effects of magnetic cores on output performance. However, traditional lumped parameter models are not sufficient for nanosecond pulse generation due to the natural neglect of wave propagations in secondary mode lines based on a lumped parameter assumption. In this paper, a distributed parameter model of transmission line transformer was established to investigate wave propagation in the secondary mode line and its influential factors through theoretical analysis and experimental verification. The wave propagation discontinuity in the secondary mode line induced by magnetic cores is emphasized. Characteristics of the magnetic core under a nanosecond pulse were obtained by experiments. Distribution and formation of the secondary mode current were determined for revealing essential wave propagation processes in secondary mode lines. The output waveform and efficiency were found to be affected dramatically by wave propagation discontinuity in secondary mode lines induced by magnetic cores. The proposed distributed parameter model was proved more suitable for nanosecond pulse generation in aspects of secondary mode current, output efficiency, and output waveform. In depth, comprehension of underlying mechanisms and a broader view of the working principle of the transmission line transformer for nanosecond pulse generation can be obtained through this research.

  8. 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.

  9. Research on the control strategy of distributed energy resources inverter based on improved virtual synchronous generator.

    PubMed

    Gao, Changwei; Liu, Xiaoming; Chen, Hai

    2017-08-22

    This paper focus on the power fluctuations of the virtual synchronous generator(VSG) during the transition process. An improved virtual synchronous generator(IVSG) control strategy based on feed-forward compensation is proposed. Adjustable parameter of the compensation section can be modified to achieve the goal of reducing the order of the system. It can effectively suppress the power fluctuations of the VSG in transient process. To verify the effectiveness of the proposed control strategy for distributed energy resources inverter, the simulation model is set up in MATLAB/SIMULINK platform and physical experiment platform is established. Simulation and experiment results demonstrate the effectiveness of the proposed IVSG control strategy.

  10. 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.

  11. 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.

  12. Research on pseudo-color image generation technology of the distribution of gaseous pollutants

    NASA Astrophysics Data System (ADS)

    Yang, Jiao; Sheng, HuaiJie; Shao, Li; Cheng, YuBao

    2016-11-01

    In order to improve the visualization of the output data of gaseous pollutants monitoring system and study pseudo-color image generation technology, this research combines the column concentration data of polluted gas with spatial position parameter to design a grey-color conversion method based on visual pseudo-color coding, generates the pseudo-color images of column concentration of the distribution of polluted gas and evaluates the pseudo-color coding scheme designed in HSI color space. The evaluation results show that the designed coding scheme can effectively conduct pseudo-color display for the concentration section of polluted gas.

  13. 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.

  14. 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.

  15. Distributed clock gating for power reduction of a programmable waveform generator for neural stimulation.

    PubMed

    Noorsal, Emilia; Sooksood, Kriangkrai; Bihr, Ulrich; Becker, Joachim; Ortmanns, Maurits

    2012-01-01

    This paper describes how to employ distributed clock gating to achieve an overall low power design of a programmable waveform generator intended for a neural stimulator. The power efficiency is enabled using global timing control combined with local amplitude distribution over a bus to the local stimulator frontends. This allows the combination of local and global clock gating for complete sub-blocks of the design. A counter and a shifter employed at the local digital stimulator reduce the design complexity for the waveform generation and thus the overall power consumptions. The average power results indicate that 63% power can be saved for the global stimulator control unit and 89-96% power can be saved for the local digital stimulator by using the proposed approach. The circuit has been implemented and successfully tested in a 0.35 µm AMS HVCMOS technology.

  16. 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.

  17. [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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. FABSIM: a software for generating FST distributions with various ascertainment biases.

    PubMed

    Ramírez-Soriano, Anna; Calafell, Francesc

    2008-12-01

    We have developed a software that applies ascertainment bias on simulated DNA sequences and calculates F(ST) on them, so they can be used to generate neutral distributions that are appropriate to test whether the genetic differentiation of a particular gene between populations is compatible with neutral evolution, or, on the contrary, suggests local adaptation by natural selection. FABSIM is available from http://www.snpator.com/public/downloads/aRamirez/FABSIM/.

  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. 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.

  6. 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.

  7. 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.

  8. 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

  9. Accurately simulating aircraft sortie generation within distributed interactive simulations using an airbase logistics model

    NASA Astrophysics Data System (ADS)

    Banks, Sheila B.; Stytz, Martin R.

    1997-07-01

    This paper describes the development of an accurate airbase sortie generation capability for inclusion within military training distributed virtual environments (DVEs). Current training military DVEs lack appropriate modeling of airbase logistics and, therefore, the corresponding sortie generation model incorrectly portrays an airbase's wartime operational capabilities. As a result, DVE training participants, at both the command and staff level, develop expectations that are not realized in a real world environment and actually receive negative training. The airbase logistics system (ALS) provides accurate sortie generation capabilities by the incorporation of an existing constructive airbase logistics model, CWTSAR, into distributed interactive simulation (DIS) based military training DVEs. The airbase logistics system integrates CWTSAR with an object-oriented run-time data repository [the common object database (CODB)], the modular semi-autonomous forces' (ModSAF) network utilities, and the command and control simulation interface language (CCSIL) for communication between the ALS and other DIS-compatible systems in the DVE. The paper provides details on the sortie generation capability of ALS and its necessary interface utilities. The planned future development efforts to overcome shortfalls within ALS are also addressed within this paper.

  10. 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.

  11. 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

  12. 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

  13. 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.

  14. 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.

  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

    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.

  16. GREENHOUSE GAS REDUCTION POTENTIAL WITH COMBINED HEAT AND POWER WITH DISTRIBUTED GENERATION PRIME MOVERS - ASME 2012

    SciTech Connect

    Curran, Scott; Theiss, Timothy J; Bunce, Michael

    2012-01-01

    Pending or recently enacted greenhouse gas regulations and mandates are leading to the need for current and feasible GHG reduction solutions including combined heat and power (CHP). Distributed generation using advanced reciprocating engines, gas turbines, microturbines and fuel cells has been shown to reduce greenhouse gases (GHG) compared to the U.S. electrical generation mix due to the use of natural gas and high electrical generation efficiencies of these prime movers. Many of these prime movers are also well suited for use in CHP systems which recover heat generated during combustion or energy conversion. CHP increases the total efficiency of the prime mover by recovering waste heat for generating electricity, replacing process steam, hot water for buildings or even cooling via absorption chilling. The increased efficiency of CHP systems further reduces GHG emissions compared to systems which do not recover waste thermal energy. Current GHG mandates within the U.S Federal sector and looming GHG legislation for states puts an emphasis on understanding the GHG reduction potential of such systems. This study compares the GHG savings from various state-of-the- art prime movers. GHG reductions from commercially available prime movers in the 1-5 MW class including, various industrial fuel cells, large and small gas turbines, micro turbines and reciprocating gas engines with and without CHP are compared to centralized electricity generation including the U.S. mix and the best available technology with natural gas combined cycle power plants. The findings show significant GHG saving potential with the use of CHP. Also provided is an exploration of the accounting methodology for GHG reductions with CHP and the sensitivity of such analyses to electrical generation efficiency, emissions factors and most importantly recoverable heat and thermal recovery efficiency from the CHP system.

  17. Study on distributed generation algorithm of variable precision concept lattice based on ontology heterogeneous database

    NASA Astrophysics Data System (ADS)

    WANG, Qingrong; ZHU, Changfeng

    2017-06-01

    Integration of distributed heterogeneous data sources is the key issues under the big data applications. In this paper the strategy of variable precision is introduced to the concept lattice, and the one-to-one mapping mode of variable precision concept lattice and ontology concept lattice is constructed to produce the local ontology by constructing the variable precision concept lattice for each subsystem, and the distributed generation algorithm of variable precision concept lattice based on ontology heterogeneous database is proposed to draw support from the special relationship between concept lattice and ontology construction. Finally, based on the standard of main concept lattice of the existing heterogeneous database generated, a case study has been carried out in order to testify the feasibility and validity of this algorithm, and the differences between the main concept lattice and the standard concept lattice are compared. Analysis results show that this algorithm above-mentioned can automatically process the construction process of distributed concept lattice under the heterogeneous data sources.

  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. 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.)

  20. 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.

  1. 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.

  2. 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.

  3. Exploring changes in the spatial distribution of stream baseflow generation during a seasonal recession

    USGS Publications Warehouse

    Payn, R.A.; Gooseff, M.N.; McGlynn, B.L.; Bencala, K.E.; Wondzell, S.M.

    2012-01-01

    Relating watershed structure to streamflow generation is a primary focus of hydrology. However, comparisons of longitudinal variability in stream discharge with adjacent valley structure have been rare, resulting in poor understanding of the distribution of the hydrologic mechanisms that cause variability in streamflow generation along valleys. This study explores detailed surveys of stream base flow across a gauged, 23 km2 mountain watershed. Research objectives were (1) to relate spatial variability in base flow to fundamental elements of watershed structure, primarily topographic contributing area, and (2) to assess temporal changes in the spatial patterns of those relationships during a seasonal base flow recession. We analyzed spatiotemporal variability in base flow using (1) summer hydrographs at the study watershed outlet and 5 subwatershed outlets and (2) longitudinal series of discharge measurements every ~100 m along the streams of the 3 largest subwatersheds (1200 to 2600 m in valley length), repeated 2 to 3 times during base flow recession. Reaches within valley segments of 300 to 1200 m in length tended to demonstrate similar streamflow generation characteristics. Locations of transitions between these segments were consistent throughout the recession, and tended to be collocated with abrupt longitudinal transitions in valley slope or hillslope-riparian characteristics. Both within and among subwatersheds, correlation between the spatial distributions of streamflow and topographic contributing area decreased during the recession, suggesting a general decrease in the influence of topography on stream base flow contributions. As topographic controls on base flow evidently decreased, multiple aspects of subsurface structure were likely to have gained influence.

  4. 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.

  5. 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

  6. 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.

  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. 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.; hide

    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.

  9. 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.

  10. 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.

  11. Transverse circular-polarized Bessel beam generation by inward cylindrical aperture distribution.

    PubMed

    Pavone, S C; Ettorre, M; Casaletti, M; Albani, M

    2016-05-16

    In this paper the focusing capability of a radiating aperture implementing an inward cylindrical traveling wave tangential electric field distribution directed along a fixed polarization unit vector is investigated. In particular, it is shown that such an aperture distribution generates a non-diffractive Bessel beam whose transverse component (with respect to the normal of the radiating aperture) of the electric field takes the form of a zero-th order Bessel function. As a practical implementation of the theoretical analysis, a circular-polarized Bessel beam launcher, made by a radial parallel plate waveguide loaded with several slot pairs, arranged on a spiral pattern, is designed and optimized. The proposed launcher performance agrees with the theoretical model and exhibits an excellent polarization purity.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. Voltage distribution over capacitively coupled plasma electrode for atmospheric-pressure plasma generation

    PubMed Central

    2013-01-01

    When capacitively coupled plasma (CCP) is used to generate large-area plasma, the standing wave effect becomes significant, which results in the hindering of the uniform plasma process such as in a plasma etcher or plasma chemical vapor deposition. In this study, the transmission line modeling method is applied to calculate the voltage distribution over atmospheric-pressure CCP electrodes with the size of 1 m × 0.2 m. The measured plasma impedance in our previous study was used in the present calculation. The results of the calculations clearly showed the effects of excitation frequency and the impedance of the plasma on the form of the voltage distribution caused by the standing wave effect. In the case of 150 MHz frequency, the standing wave effect causes a drastic change in the voltage distribution via plasma ignition; however, the change is small for 13.56 MHz. It was also clarified that the power application position is important for obtaining a uniform voltage distribution. PMID:23634893

  2. Voltage distribution over capacitively coupled plasma electrode for atmospheric-pressure plasma generation.

    PubMed

    Shuto, Mitsutoshi; Tomino, Fukumi; Ohmi, Hiromasa; Kakiuchi, Hiroaki; Yasutake, Kiyoshi

    2013-05-01

    When capacitively coupled plasma (CCP) is used to generate large-area plasma, the standing wave effect becomes significant, which results in the hindering of the uniform plasma process such as in a plasma etcher or plasma chemical vapor deposition. In this study, the transmission line modeling method is applied to calculate the voltage distribution over atmospheric-pressure CCP electrodes with the size of 1 m × 0.2 m. The measured plasma impedance in our previous study was used in the present calculation. The results of the calculations clearly showed the effects of excitation frequency and the impedance of the plasma on the form of the voltage distribution caused by the standing wave effect. In the case of 150 MHz frequency, the standing wave effect causes a drastic change in the voltage distribution via plasma ignition; however, the change is small for 13.56 MHz. It was also clarified that the power application position is important for obtaining a uniform voltage distribution.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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).

  8. Design optimization of a fuzzy distributed generation (DG) system with multiple renewable energy sources

    NASA Astrophysics Data System (ADS)

    Ganesan, T.; Elamvazuthi, I.; Shaari, Ku Zilati Ku; Vasant, P.

    2012-09-01

    The global rise in energy demands brings major obstacles to many energy organizations in providing adequate energy supply. Hence, many techniques to generate cost effective, reliable and environmentally friendly alternative energy source are being explored. One such method is the integration of photovoltaic cells, wind turbine generators and fuel-based generators, included with storage batteries. This sort of power systems are known as distributed generation (DG) power system. However, the application of DG power systems raise certain issues such as cost effectiveness, environmental impact and reliability. The modelling as well as the optimization of this DG power system was successfully performed in the previous work using Particle Swarm Optimization (PSO). The central idea of that work was to minimize cost, minimize emissions and maximize reliability (multi-objective (MO) setting) with respect to the power balance and design requirements. In this work, we introduce a fuzzy model that takes into account the uncertain nature of certain variables in the DG system which are dependent on the weather conditions (such as; the insolation and wind speed profiles). The MO optimization in a fuzzy environment was performed by applying the Hopfield Recurrent Neural Network (HNN). Analysis on the optimized results was then carried out.

  9. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species.

    PubMed

    Aubry, Keith B; Raley, Catherine M; McKelvey, Kevin S

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated for rare, elusive, and cryptic species that are prone to misidentification in the field. We investigated this question for the fisher (Pekania pennanti), a forest carnivore of conservation concern in the Pacific States that is often confused with the more common Pacific marten (Martes caurina). Fisher occurrence records supported by physical evidence (verifiable records) were available from a limited area, whereas occurrence records of unknown quality (unscreened records) were available from throughout the fisher's historical range. We reserved 20% of the verifiable records to use as a test sample for both models and generated SDMs with each dataset using Maxent. The verifiable model performed substantially better than the unscreened model based on multiple metrics including AUCtest values (0.78 and 0.62, respectively), evaluation of training and test gains, and statistical tests of how well each model predicted test localities. In addition, the verifiable model was consistent with our knowledge of the fisher's habitat relations and potential distribution, whereas the unscreened model indicated a much broader area of high-quality habitat (indices > 0.5) that included large expanses of high-elevation habitat that fishers do not occupy. Because Pacific martens remain relatively common in upper elevation habitats in the Cascade Range and Sierra Nevada, the SDM based on unscreened records likely reflects primarily a conflation of marten and fisher habitat. Consequently, accurate identifications are far more important than the spatial extent of occurrence records for generating reliable SDMs for the

  10. 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

  11. 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.

  12. Calculation method for computer-generated holograms considering various reflectance distributions based on microfacets with various surface roughnesses.

    PubMed

    Yamaguchi, Kazuhiro; Ichikawa, Tsubasa; Sakamoto, Yuji

    2011-12-01

    Computer-generated holograms are generated by three-dimensional technology, and they can be used to reconstruct natural and virtual objects by simulating light waves based on holography. This research was an improvement on previous work that took into consideration reflectance distributions from the various roughnesses of objects. The previous work generated roughness by using a simple model, so that only simple roughness was generated. The proposed method generated more complex roughness than that in the previous work, and the influence of roughness on the reflectance distributions was investigated. Computer simulations, which were compared with the reflectance distributions from the various roughnesses, were carried out. Moreover, computational and optical reconstructions were carried out as examples of reconstructions. As a result of the experiments, we confirmed that the various roughnesses actually influenced the reflectance distributions. © 2011 Optical Society of America

  13. 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

  14. 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.

  15. 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

  16. Generating the local oscillator "locally" in continuous-variable quantum key distribution based on coherent detection

    DOE PAGES

    Qi, Bing; Lougovski, Pavel; Pooser, Raphael C.; ...

    2015-10-21

    Continuous-variable quantum key distribution (CV-QKD) protocols based on coherent detection have been studied extensively in both theory and experiment. In all the existing implementations of CV-QKD, both the quantum signal and the local oscillator (LO) are generated from the same laser and propagate through the insecure quantum channel. This arrangement may open security loopholes and limit the potential applications of CV-QKD. In our paper, we propose and demonstrate a pilot-aided feedforward data recovery scheme that enables reliable coherent detection using a “locally” generated LO. Using two independent commercial laser sources and a spool of 25-km optical fiber, we construct amore » coherent communication system. The variance of the phase noise introduced by the proposed scheme is measured to be 0.04 (rad2), which is small enough to enable secure key distribution. This technology opens the door for other quantum communication protocols, such as the recently proposed measurement-device-independent CV-QKD, where independent light sources are employed by different users.« less

  17. Evolution of the angular distribution of laser-generated fast electrons due to resistive self-collimation

    NASA Astrophysics Data System (ADS)

    Robinson, A. P. L.; Schmitz, H.

    2015-10-01

    The evolution of the angular distribution of laser-generated fast electrons propagating in dense plasmas is studied by 3D numerical simulations. As resistively generated magnetic fields can strongly influence and even pinch the fast electron beam, the question of the effect on the angular distribution is of considerable interest. It was conjectured that in the limit of strong collimation, there will only be minimal changes to the angular distribution, whereas the largest reduction in the angular distribution will occur where there is only modest pinching of the fast electron beam and the beam is able to expand considerably. The results of the numerical simulations indicate this conjecture.

  18. Framework for Generating Spatially Distributed Soil Moisture for Heterogeneous Landscapes at Operational Scales

    NASA Astrophysics Data System (ADS)

    Gaur, N.; Mohanty, B.

    2016-12-01

    Soil moisture forms the interface at which the partitioning of the energy, carbon and water budget for the land-surface occurs. Its spatial and temporal variability impacts different fields of application at varying extent scales like agriculture at the field scale, meteorology at the regional scale and climate change assessment at the global scale. However, there exists a discrepancy in support scales of sparsely distributed observed soil moisture data which is of the order of a few centimeters and remote sensing support scales that are required by spatially distributed eco-hydrologic models. This research provides a framework to generate spatial patterns of soil moisture at the operational modeling scales. The framework comprises of determination of the dominant land-surface controls of near-surface soil moisture dynamics between point and satellite support scale (25.6 km); and developing a spatially transferable look-up table - Scale-Wetness-Heterogeneity (SWHET) cuboid to describe the spatial patterns of soil moisture redistribution for heterogeneous landscapes at different operational scales. The dominant land-surface factors controlling soil moisture distribution at different scales were determined by developing a Shannon entropy based technique and non-decimated wavelet transforms. It was found that the land-surface controls on soil moisture vary with hydro-climate and antecedent wetness conditions. In general, the effect of soil was found to reduce with coarsening support scale while the effect of topography and vegetation increased. The SWHET cuboid (Figure 1) is hydro-climate specific and describes the relationship between the spatial correlation structures of the dominant biophysical factor and soil moisture redistribution for regions with complex heterogeneity described using a novel heterogeneity index. The spatial transferability of the SWHET cuboid to generate spatial patterns of footprint scale soil moisture was tested between two similar hydro

  19. 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.

  20. 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.

  1. 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.

  2. Generation mechanism of nonlinear ultrasonic Lamb waves in thin plates with randomly distributed micro-cracks.

    PubMed

    Zhao, Youxuan; Li, Feilong; Cao, Peng; Liu, Yaolu; Zhang, Jianyu; Fu, Shaoyun; Zhang, Jun; Hu, Ning

    2017-08-01

    Since the identification of micro-cracks in engineering materials is very valuable in understanding the initial and slight changes in mechanical properties of materials under complex working environments, numerical simulations on the propagation of the low frequency S0 Lamb wave in thin plates with randomly distributed micro-cracks were performed to study the behavior of nonlinear Lamb waves. The results showed that while the influence of the randomly distributed micro-cracks on the phase velocity of the low frequency S0 fundamental waves could be neglected, significant ultrasonic nonlinear effects caused by the randomly distributed micro-cracks was discovered, which mainly presented as a second harmonic generation. By using a Monte Carlo simulation method, we found that the acoustic nonlinear parameter increased linearly with the micro-crack density and the size of micro-crack zone, and it was also related to the excitation frequency and friction coefficient of the micro-crack surfaces. In addition, it was found that the nonlinear effect of waves reflected by the micro-cracks was more noticeable than that of the transmitted waves. This study theoretically reveals that the low frequency S0 mode of Lamb waves can be used as the fundamental waves to quantitatively identify micro-cracks in thin plates. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. 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.

  4. 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.

  5. 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.

  6. Generation rate and particle size distribution of wood dust by handheld sanding operation.

    PubMed

    Ojima, Jun

    2016-11-29

    The International Agency for Research on Cancer (IARC) and Japan Society for Occupational Health (JSOH) classified wood dust as a human carcinogen. Former studies have suggested that sanding with a portable sander is one of the processes that are liable to cause highest exposure to wood dust. However, the wood dust by sanding operation has not been investigated sufficiently. In this study, the generation rate and the particle size distribution of the wood dust produced by handheld sanding operation were observed by laboratory experiments. Beech and cypress were taken as typical hard and soft wood specimen respectively, and sanded with a portable sander. Three grades of sand paper (coarse, medium, fine) were attached to the sander in turn to be tested. The quantity of the wood dust produced by the sander was measured by weighing the specimen before and after the sanding and then the generation rate of the dust was calculated. Soft wood generated more dust than hard wood due to the difference in abrasion durability. A coarse sand paper produced more dust than a fine sand paper. The particles of less than 1 μm diameter were scarcely observed in the wood dust. When the specimens were sanded with a fine sand paper, the mass median aerodynamic diameters of beech dust and cypress dust were 9.0 μm and 9.8 μm, respectively. Respirable wood dust is able to be controlled by general ventilation with more than 0.7-4.2 m(3)/min ventilation rate.

  7. 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)

  8. 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.

  9. An Advanced Next Generation Archival and Distribution System for Global Atmospheric Science Research and Applications

    NASA Astrophysics Data System (ADS)

    Closs, J. W.; Baskin, W. E.; Piatko, P.; Ritchey, N. A.

    2007-12-01

    NASA's Atmospheric Science Data Center at the NASA Langley Research Center has developed a new state-of- the-art data archival, and distribution system to serve the atmospheric sciences data provider and user communities. The new system, called Archive - Next Generation (ANGe), is replacing two large-scale science data management systems, and is designed with a distributed, multi-tier, serviced-based, message oriented architecture enabling new methods for searching, accessing, and customizing data. The previous two systems required a user to actively manage a session in a web browser to sequentially search for and obtain data. The ANGe system is architected to allow programmatic calls to the archive via web services to obtain multiple data sets of interest to the user. Web service access to the archive enhances the user's ability to utilize multiple data sets managed at different locations via a Grid computing environment. This technology distributes computationally intensive data processing for large data sets, and greatly improves the efficiency of extracting smaller pieces of data of interest to a specific study. Geospatial metadata is managed in a PostGIS-enabled database, allowing for integration with mainstream GIS utilities and applications. The Atmospheric Science Data Center is also producing custom value-added data products and tailoring access to information and data to meet the needs of a diverse user community. Details of these new data access tools and capabilities, and planned enhancements will be discussed. The Atmospheric Science Data Center in Langley's Science Directorate leads NASA's program for the processing, archival and distribution of Earth science data in the areas of radiation budget, clouds, aerosols, and tropospheric chemistry. The Data Center was established in 1991 to support NASA's Earth Observing System and the U.S. Global Change Research Program. It is unique among NASA data centers in the size of its archive, cutting edge

  10. 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

  11. Single-site vs. multi-site rainfall generation and the role of parametric rainfall distributions in lumped hydrological modelling

    NASA Astrophysics Data System (ADS)

    Breinl, Korbinian

    2017-04-01

    It was examined whether a lumped hydrological model driven with lumped daily precipitation time series from a single-site rainfall generator can produce equally good simulation results compared to using a multi-site rainfall generator, where synthetic precipitation is first generated at multiple sites and subsequently lumped. Driving a lumped hydrological model with synthetic rainfall time series from stochastic rainfall generation is a fast methodology in hydrological impact assessment, for example for the assessment of low frequent extreme flows when long synthetic discharge time series are required. The use of a lumped hydrological model appears to justify the application of a straightforward single-site "Richardson type" rainfall generator, where rainfall observations from several sites in the catchment are first lumped and then used for parametric distribution fitting. An alternative approach is the application of a multi-site rainfall generator, where rainfall is first generated at all available rainfall sites and subsequently lumped to feed the hydrological model. The higher complexity of multi-site rainfall generators makes the application of a single-site approach attractive as the latter can be set up fairly easily. This study revealed, however, that well-established parametric rainfall distributions for single-site rainfall observations are not suitable for lumped rainfall time series in the Alpine catchments examined, and can lead to bias in the simulation of extreme flows when using a single-site rainfall generator. The issue can be avoided by either using a multi-site rainfall generator, which is considerably less sensitive to the choice of the parametric rainfall distribution or by a careful choice of the parametric rainfall distribution fitted to lumped rainfall time series when using a single-site rainfall generator. In this study three different rainfall generators were tested: two different single-site "Richardson type" models (one with and one

  12. The importance of data quality for generating reliable distribution models for rare, elusive, and cryptic species

    PubMed Central

    Aubry, Keith B.; Raley, Catherine M.; McKelvey, Kevin S.

    2017-01-01

    The availability of spatially referenced environmental data and species occurrence records in online databases enable practitioners to easily generate species distribution models (SDMs) for a broad array of taxa. Such databases often include occurrence records of unknown reliability, yet little information is available on the influence of data quality on SDMs generated for rare, elusive, and cryptic species that are prone to misidentification in the field. We investigated this question for the fisher (Pekania pennanti), a forest carnivore of conservation concern in the Pacific States that is often confused with the more common Pacific marten (Martes caurina). Fisher occurrence records supported by physical evidence (verifiable records) were available from a limited area, whereas occurrence records of unknown quality (unscreened records) were available from throughout the fisher’s historical range. We reserved 20% of the verifiable records to use as a test sample for both models and generated SDMs with each dataset using Maxent. The verifiable model performed substantially better than the unscreened model based on multiple metrics including AUCtest values (0.78 and 0.62, respectively), evaluation of training and test gains, and statistical tests of how well each model predicted test localities. In addition, the verifiable model was consistent with our knowledge of the fisher’s habitat relations and potential distribution, whereas the unscreened model indicated a much broader area of high-quality habitat (indices > 0.5) that included large expanses of high-elevation habitat that fishers do not occupy. Because Pacific martens remain relatively common in upper elevation habitats in the Cascade Range and Sierra Nevada, the SDM based on unscreened records likely reflects primarily a conflation of marten and fisher habitat. Consequently, accurate identifications are far more important than the spatial extent of occurrence records for generating reliable SDMs for the

  13. 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

  14. 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.

  15. 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.

  16. An optimization model for energy generation and distribution in a dynamic facility

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.

    1981-01-01

    An analytical model is described using linear programming for the optimum generation and distribution of energy demands among competing energy resources and different economic criteria. The model, which will be used as a general engineering tool in the analysis of the Deep Space Network ground facility, considers several essential decisions for better design and operation. The decisions sought for the particular energy application include: the optimum time to build an assembly of elements, inclusion of a storage medium of some type, and the size or capacity of the elements that will minimize the total life-cycle cost over a given number of years. The model, which is structured in multiple time divisions, employ the decomposition principle for large-size matrices, the branch-and-bound method in mixed-integer programming, and the revised simplex technique for efficient and economic computer use.

  17. Effects of Distributed Generation on Overcurrent Relay Coordination and an Adaptive Protection Scheme

    NASA Astrophysics Data System (ADS)

    Ilik, Semih C.; Arsoy, Aysen B.

    2017-07-01

    Integration of distributed generation (DG) such as renewable energy sources to electrical network becomes more prevalent in recent years. Grid connection of DG has effects on load flow directions, voltage profile, short circuit power and especially protection selectivity. Applying traditional overcurrent protection scheme is inconvenient when system reliability and sustainability are considered. If a fault happens in DG connected network, short circuit contribution of DG, creates additional branch element feeding the fault current; compels to consider directional overcurrent (OC) protection scheme. Protection coordination might get lost for changing working conditions when DG sources are connected. Directional overcurrent relay parameters are determined for downstream and upstream relays when different combinations of DG connected singular or plural, on radial test system. With the help of proposed flow chart, relay parameters are updated and coordination between relays kept sustained for different working conditions in DigSILENT PowerFactory program.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. An Ensemble Generator for Quantitative Precipitation Estimation Based on Censored Shifted Gamma Distributions

    NASA Astrophysics Data System (ADS)

    Wright, D.; Kirschbaum, D.; Yatheendradas, S.

    2016-12-01

    The considerable uncertainties associated with quantitative precipitation estimates (QPE), whether from satellite platforms, ground-based weather radar, or numerical weather models, suggest that such QPE should be expressed as distributions or ensembles of possible values, rather than as single values. In this research, we borrow a framework from the weather forecast verification community, to "correct" satellite precipitation and generate ensemble QPE. This approach is based on the censored shifted gamma distribution (CSGD). The probability of precipitation, central tendency (i.e. mean), and the uncertainty can be captured by the three parameters of the CSGD. The CSGD can then be applied for simulation of rainfall ensembles using a flexible nonlinear regression framework, whereby the CSGD parameters can be conditioned on one or more reference rainfall datasets and on other time-varying covariates such as modeled or measured estimates of precipitable water and relative humidity. We present the framework and initial results by generating precipitation ensembles based on the Tropical Rainfall Measuring Mission Multi-satellite Precipitation Analysis (TMPA) dataset, using both NLDAS and PERSIANN-CDR precipitation datasets as references. We also incorporate a number of covariates from MERRA2 reanalysis including model-estimated precipitation, precipitable water, relative humidity, and lifting condensation level. We explore the prospects for applying the framework and other ensemble error models globally, including in regions where high-quality "ground truth" rainfall estimates are lacking. We compare the ensemble outputs against those of an independent rain gage-based ensemble rainfall dataset. "Pooling" of regional rainfall observations is explored as one option for improving ensemble estimates of rainfall extremes. The approach has potential applications in near-realtime, retrospective, and scenario modeling of rainfall-driven hazards such as floods and landslides

  4. 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.

  5. 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.

  6. An Advanced Next Generation Archival and Distribution System for Global Atmospheric Science Research

    NASA Astrophysics Data System (ADS)

    Ritchey, N. A.; Kusterer, J. M.

    2008-12-01

    NASA's Atmospheric Science Data Center at the NASA Langley Research Center has developed a new state- of-the-art data archival, and distribution system to serve the atmospheric sciences data provider and user communities. The new system, called Archive - Next Generation (ANGe), is replacing a large-scale science data management system, and is designed with a distributed, multi-tier, serviced-based, message oriented architecture enabling new methods for searching, accessing, and customizing data. The previous system required a user to actively manage a session in a web browser to sequentially search for and obtain data. The ANGe system is architected to allow programmatic calls to the archive via web services to obtain multiple data sets of interest to the user. The ANGe system is currently supporting Clouds and the Earth's Radiant Energy System (CERES) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) data ingest, archival and distribution. In the future it will support CERES on National Polar-orbiting Operational Environmental Satellite System (NPOESS). Potential enhancements to this new system are web service access to the archive improving the user's ability to utilize multiple data sets managed at different locations via a Grid/Cloud computing environment. This technology distributes computationally intensive data processing for large data sets, and greatly improves the efficiency of extracting smaller pieces of data of interest to a specific study. Geospatial metadata can be managed in a PostGIS-enabled database, allowing for integration with mainstream GIS utilities and applications. The Atmospheric Science Data Center proposes to produce custom value-added data products and tailoring access to information and data to meet the needs of a diverse user community. Details of these new data access tools and capabilities, and potential enhancements will be discussed. The Atmospheric Science Data Center in Langley's Science

  7. 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.

  8. 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.

  9. 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.

  10. Generating 3D depletion distribution in an achromatic single-channel monolithic system

    NASA Astrophysics Data System (ADS)

    Fallet, Clement; Lindberg, Arvid; Sirat, Gabriel Y.

    2016-02-01

    Recent developments have shown that conical diffraction by a biaxial crystal can create a vortex beam for use in 2D STED microscopy. It has been shown that this concept can be extended and also generate the depletion distributions used for 3D STED microscopy. A single beam passes through a biaxial crystal that creates two co-propagating, co-localized beams; the first one is used for lateral depletion, and the other one for axial depletion. The two beams are crossed-polarized and thus do not interfere. We will show that the 3D distribution can be made achromatic, i.e. several depletion wavelengths can travel through a common path and still be shaped into the appropriate pattern by optimizing the geometry of the system. This system enables true one-channel 3D depletion at multiple wavelengths ranging from 580nm to 770nm, thus covering most of the conventional depletion wavelengths currently used. Preliminary results of depletion PSFs will be presented and the advantages and limitations of this system will be discussed as well as the experimental considerations required to successfully obtain the desired PSFs.

  11. 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.

  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. 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.

  14. 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.

  15. Using Python to generate AHPS-based precipitation simulations over CONUS using Amazon distributed computing

    NASA Astrophysics Data System (ADS)

    Machalek, P.; Kim, S. M.; Berry, R. D.; Liang, A.; Small, T.; Brevdo, E.; Kuznetsova, A.

    2012-12-01

    We describe how the Climate Corporation uses Python and Clojure, a language impleneted on top of Java, to generate climatological forecasts for precipitation based on the Advanced Hydrologic Prediction Service (AHPS) radar based daily precipitation measurements. A 2-year-long forecasts is generated on each of the ~650,000 CONUS land based 4-km AHPS grids by constructing 10,000 ensembles sampled from a 30-year reconstructed AHPS history for each grid. The spatial and temporal correlations between neighboring AHPS grids and the sampling of the analogues are handled by Python. The parallelization for all the 650,000 CONUS stations is further achieved by utilizing the MAP-REDUCE framework (http://code.google.com/edu/parallel/mapreduce-tutorial.html). Each full scale computational run requires hundreds of nodes with up to 8 processors each on the Amazon Elastic MapReduce (http://aws.amazon.com/elasticmapreduce/) distributed computing service resulting in 3 terabyte datasets. We further describe how we have productionalized a monthly run of the simulations process at full scale of the 4km AHPS grids and how the resultant terabyte sized datasets are handled.

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. Generation, compression, and propagation of pulse trains in the nonlinear Schrödinger equation with distributed coefficients.

    PubMed

    Wang, Luyun; Li, Lu; Li, Zhonghao; Zhou, Guosheng; Mihalache, Dumitru

    2005-09-01

    The generalized nonlinear Schrödinger model with distributed dispersion, nonlinearity, and gain or loss is considered and the explicit, analytical solutions describing the dynamics of bright solitons on a continuous-wave background are obtained in quadratures. Then, the generation, compression, and propagation of pulse trains are discussed in detail. The numerical results show that solitons can be compressed by choosing the appropriate control fiber system, and pulse trains generated by modulation instability can propagate undistorsted along fibers with distributed parameters by controlling appropriately the energy of each pulse in the pulse train.

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Distributed modeling of storm flow generation in an Amazonian rain forest catchment: Effects of model parameterization

    NASA Astrophysics Data System (ADS)

    Vertessy, Robert A.; Elsenbeer, Helmut

    1999-07-01

    We describe a process-based storm flow generation model, Topog_SBM consisting of a simple bucket model for soil water accounting, a one-dimensional kinematic wave overland flow scheme, and a contour-based element network for routing surface and subsurface flows. Aside from topographic data and rainfall the model has only six input parameters: soil depth (z), saturated hydraulic conductivity at the soil surface (K0), the rate of decay in K0 with depth (m), the Manning surface roughness parameter (n), the maximum (saturated) soil water content (θs), and the minimum (residual) soil water content (θr). However, the model is fully distributed, so these values can vary in magnitude across space. The model was applied to La Cuenca, a very small rainforest catchment in western Amazonia that has been well characterized in several hydrometric and hydrochemical investigations. Total runoff, peak runoff, time of rise, and lag time were predicted for 34 events of varying magnitudes and antecedent moisture conditions. We compared results for eight different model parameterizations or "sets"; four of these were freely calibrated to yield the best possible model fit to runoff data, whereas the other four were constrained (in various ways) by the use of actual K0 data gathered for the catchment. The eight sets were calibrated on either one of three events or on the three events jointly to illustrate the importance of calibration event selection on model performance. Model performance was evaluated by comparing observed and predicted (1) storm flow hydrograph attributes and (2) spatiotemporal patterns of overland flow occurrence across the catchment. The model generally predicted the right amount of runoff but usually underpredicted the peak runoff rate and overpredicted the time of rise. The "best" parameterization could credibly predict hydrographs for only about half of the events. Significant, and sometimes gross, errors were encountered for about one fourth of the events

  3. 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

  4. Modeling and control of hybrid wind/photovoltaic/fuel cell distributed generation systems

    NASA Astrophysics Data System (ADS)

    Wang, Caisheng

    Due to ever increasing energy consumption, rising public awareness of environmental protection, and steady progress in power deregulation, alternative (i.e., renewable and fuel cell based) distributed generation (DG) systems have attracted increased interest. Wind and photovoltaic (PV) power generation are two of the most promising renewable energy technologies. Fuel cell (FC) systems also show great potential in DG applications of the future due to their fast technology development and many merits they have, such as high efficiency, zero or low emission (of pollutant gases) and flexible modular structure. The modeling and control of a hybrid wind/PV/FC DG system is addressed in this dissertation. Different energy sources in the system are integrated through an AC bus. Dynamic models for the main system components, namely, wind energy conversion system (WECS), PV energy conversion system (PVECS), fuel cell, electrolyzer, power electronic interfacing circuits, battery, hydrogen storage tank, gas compressor and gas pressure regulator, are developed. Two types of fuel cells have been modeled in this dissertation: proton exchange membrane fuel cell (PEMFC) and solid oxide fuel cell (SOFC). Power control of a grid-connected FC system as well as load mitigation control of a stand-alone FC system are investigated. The pitch angle control for WECS, the maximum power point tracking (MPPT) control for PVECS, and the control for electrolyzer and power electronic devices, are also addressed in the dissertation. Based on the dynamic component models, a simulation model for the proposed hybrid energy system has been developed using MATLAB/Simulink. The overall power management strategy for coordinating the power flows among the different energy sources is presented in the dissertation. Simulation studies have been carried out to verify the system performance under different scenarios using a practical load profile and real weather data. The results show that the overall power

  5. Distributed model of rainfall and snowmelt runoff generation for a mountainous river basin

    NASA Astrophysics Data System (ADS)

    Kuchment, Lev; Demidov, Victor; Gelfan, Alexander

    2010-05-01

    The distributed physically based model of snowmelt runoff generation for a mountainous river basin which allows for taking into account horisontal and vertical heterogeneity of hydrological processes has been developed. The model is based on a finite-element schematization of the river basin and includes the description of processes of snow cover formation, snow and ice melting, evaporation and infiltration, overland and subsurface flow, water movement in the river network. Choice of finite element areas is based on difference in topography, soil, vegetation, land use. In the basin, 512 finite element areas and 64 finite-elements of river channels have been singled out. The input data (the air temperature, precipitation, air humidity, wind speed and cloudiness) are calculated using available observations, as well as interpolation and extrapolation procedures accounted for vegetation and exposition of finite-element areas. The case-study was carried out for the upper part of the Kuban River basin (the North Caucasus region). The catchment covers an area of 16,900 km2 and includes the highest Caucasus peak Elbrus (5600 m). The highest meteorological station is located at the altitude 2039 m. The flood runoff is commonly of mixed rainfall-snowmelt origin. The ice melt gives about 10% of annual runoff. Six parameters of the model have been calibrated, against the observed hydrographs and snow measurements. The test of the model was carried out on the basis of observed hydrographs for 11 year period, including the catastrophic flood of 2002. The satisfied correspondences of observed and calculated hydrographs have been obtained.

  6. 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.

  7. 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.

  8. Warpage Generation Mechanism by Cooling Speed Distribution in Actual Injection Molding

    NASA Astrophysics Data System (ADS)

    Satoh, Kazuhito; Matsubara, Eiji; Yamabe, Masashi

    In some cases, warpage failure occurs in the injection molding plate. This warpage can be predicted by using injection molding CAE. However, the prediction accuracy is not enough in the warpage analysis of injection molding CAE. The warpage generation mechanism changes according to the material and shape. The mechanism has not been clarified in each condition. For example, there is difference in the cooling speed of the real injection plate in each position. In this report, we considered the influence of the difference of mold temperature on warpage, assuming the mold temperature to be an asymmetric condition. And the following conclusions were arrived at. Moreover, upon examining the influence of mold temperature difference on warpage of PP plate, the following conclusions were obtained. 1) The amount of warpage grows in an asymmetrical mold temperature condition. The amount of warpage increases in the case of high mold temperature even if the difference of temperature between fixed side and moved side is constant. 2) In the case of asymmetrical mold temperature, the distribution of crystallinity becomes asymmetrical in the thickness direction. However, the thermal expansion coefficient is isotropy and constant. 3) The key factor of warpage in asymmetrical mold temperature conditions in PP is induced by thermal effect. 4) The resin flow of asymmetrical mold temperature conditions in PP becomes a symmetrical flow. This is thought to be influenced by heat of shearing and latent heat of crystallization. 5) Even under the same mold temperature asymmetric condition, differences in material cause the influence of mold temperature on flow to differ.

  9. 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.

  10. Calculation method of reflectance distributions for computer-generated holograms using the finite-difference time-domain method.

    PubMed

    Ichikawa, Tsubasa; Sakamoto, Yuji; Subagyo, Agus; Sueoka, Kazuhisa

    2011-12-01

    The research on reflectance distributions in computer-generated holograms (CGHs) is particularly sparse, and the textures of materials are not expressed. Thus, we propose a method for calculating reflectance distributions in CGHs that uses the finite-difference time-domain method. In this method, reflected light from an uneven surface made on a computer is analyzed by finite-difference time-domain simulation, and the reflected light distribution is applied to the CGH as an object light. We report the relations between the surface roughness of the objects and the reflectance distributions, and show that the reflectance distributions are given to CGHs by imaging simulation. © 2011 Optical Society of America

  11. 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

  12. Energy Cost of an Independent Micro-grid with Control of Power Output Sharing of a Distributed Engine Generator

    NASA Astrophysics Data System (ADS)

    Obara, Shin'ya

    Small kerosene diesel-engine power generators are introduced into an independent micro-grid (IMG) that connects 20 houses, and power and heat are supplied to them. A 3 kW engine generator is installed in six houses, and a boiler and a heat storage tank are also installed, and exhaust heat to make up for insufficiency is supplied. The boiler is installed in the house that does not install the engine generator, and heat is supplied to the demand side. Partial load operation of the engine generator has a large influence on power generation efficiency. Therefore, this paper discusses the system that controls the power of the engine generator by the power distribution control system using the genetic algorithm (GA), and the control system that changes the number of operations of the engine generators according to the magnitude of the power load. As a case study, the energy-demand model of the 20 houses in Sapporo was analyzed. As a result, the annual energy cost of the number of operations system and the power distribution control system is reducible with 16% and 8% compared with the conventional method, respectively. However, it depends for this cutback effect on the heat demand characteristic greatly, and when the proposed system is introduced into a community with little heat demand, effectiveness will decrease greatly.

  13. 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.

  14. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. 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.

  16. 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.

  17. He+ and O+ EMIC waves generated by the O+ bunch distribution associated with fast magnetosonic shocks in the magnetosphere

    NASA Astrophysics Data System (ADS)

    Lee, K. H.; Lee, L. C.

    2016-12-01

    Electromagnetic ion cyclotron (EMIC) waves are often observed in the magnetosphere with frequency usually in the H+ and He+ cyclotron bands and sometimes in the O+ band. The temperature anisotropy, caused by injection of energetic ions or by compression of magnetosphere, can efficiently generate H+ EMIC waves, but not as efficient for He+ or O+ EMIC waves. Here we propose a new generation mechanism for He+ and O+ EMIC waves associated with weak fast magnetosonic shocks, which are observed in the magnetosphere. These shocks can lead to the formation of a "bunch" distribution of O+ ions in the perpendicular velocity plane. The O+ bunch distribution can excite intensive He+ EMIC waves and weak O+ and H+ waves. The dominant He+ EMIC waves are strong in quasi-perpendicular propagation and show harmonics in frequency spectrum of Fourier analysis. The proposed mechanism can explain the generation and some observed properties of He+ and O+ EMIC waves in the magnetosphere.

  18. 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.

  19. The probability distribution of wind power from a dispersed array of wind turbine generators

    NASA Astrophysics Data System (ADS)

    Carlin, J.; Haslett, J.

    1982-03-01

    A method is presented for estimating the probability distribution of wind power from a dispersed array of wind turbine sites where the correlation between wind speeds at distinct sites is less than unity. The distribution is obtained from a model for the joint probability distribution of wind speeds. This is able to incorporate arbitrary inter-site correlations. It is shown that this joint distribution reduces in the single site case to a wind speed distribution closely approximating the widely used Weibull; the multiple site power distribution is also shown to fit adequately to data on wind speeds from four sites in Western Australia. Results presented in graphical and tabular form for a range of representative cases show that a significant reduction in the variability of total wind power output may result from dispersion of aerogenerator sites; a quantitative guide to the magnitude of these effects is also provided.

  20. 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.

  1. 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)

  2. 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)

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Free-Space Quantum Key Distribution with a High Generation Rate KTP Waveguide Photon-Pair Source

    NASA Technical Reports Server (NTRS)

    Wilson, J.; Chaffee, D.; Wilson, N.; Lekki, J.; Tokars, R.; Pouch, J.; Lind, A.; Cavin, J.; Helmick, S.; Roberts, T.; hide

    2016-01-01

    NASA awarded Small Business Innovative Research (SBIR) contracts to AdvR, Inc to develop a high generation rate source of entangled photons that could be used to explore quantum key distribution (QKD) protocols. The final product, a photon pair source using a dual-element periodically- poled potassium titanyl phosphate (KTP) waveguide, was delivered to NASA Glenn Research Center in June of 2015. This paper describes the source, its characterization, and its performance in a B92 (Bennett, 1992) protocol QKD experiment.

  19. 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

  20. Distribution and generation of the overpressure system, Eastern Delaware Basin, Western Texas and Southern New Mexico: Discussion

    SciTech Connect

    Swarbrick, R.E.

    1995-12-01

    Luo et al. (1994) discussed the distribution and possible origin of a three-fold pressure system in the eastern Delaware basin. The pressure data presented in their pressure vs. depth plots were exclusively derived from drill-stem tests (DSTs), although they contend that the overpressure is also confirmed from well log responses. The paper is weakened by incorrect sourece of pressure data from DSTs, and also by poor understanding and inadequate review of the basis for overpressure generation in sedimentary basins.

  1. 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.

  2. 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

  3. 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.

  4. Distributed Noise Generation for Density Estimation Based Clustering without Trusted Third Party

    NASA Astrophysics Data System (ADS)

    Su, Chunhua; Bao, Feng; Zhou, Jianying; Takagi, Tsuyoshi; Sakurai, Kouichi

    The rapid growth of the Internet provides people with tremendous opportunities for data collection, knowledge discovery and cooperative computation. However, it also brings the problem of sensitive information leakage. Both individuals and enterprises may suffer from the massive data collection and the information retrieval by distrusted parties. In this paper, we propose a privacy-preserving protocol for the distributed kernel density estimation-based clustering. Our scheme applies random data perturbation (RDP) technique and the verifiable secret sharing to solve the security problem of distributed kernel density estimation in [4] which assumed a mediate party to help in the computation.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Inequalities in the Distribution of Education Between Countries, Sexes, Generations and Individuals.

    ERIC Educational Resources Information Center

    Kotwal, Marilyn

    The distribution of educational experience in countries belonging to the Organization for Economic Co-operation and Development (OECD) is presented in this paper. It covers those sections of the population who have terminated formal education. Educational attainment is measured in two ways: in terms of years of educational experience and by…

  10. 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.

  11. 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

  12. Distributed Storage Inverter and Legacy Generator Integration Plus Renewables Solution for Microgrids

    DTIC Science & Technology

    2015-07-01

    Reactive Power during Utility Generator Transition ........................................................ 8 Figure 5: Inverter & Energy Storage...kVAR value with reactive power support ...................................... 89 Figure 73: Minimum energy storage requirement during transition from... Reactive kVAR Kilo Watts kW Lithium Ion Li Ion Lithium-Titanate Oxide nLTO Natural gas NG Performance Objectives PO Photovoltaic PV Power

  13. 29 CFR 1910.269 - Electric power generation, transmission, and distribution.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... source of energy for electric generators, and (3) Chlorine and hydrogen systems; (C) Test sites where... program shall use a tagout system. (B) If an energy isolating device is capable of being locked out, the employer's program shall use lockout, unless the employer can demonstrate that the use of a tagout system...

  14. 29 CFR 1910.269 - Electric power generation, transmission, and distribution.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... source of energy for electric generators, and (3) Chlorine and hydrogen systems; (C) Test sites where... program shall use a tagout system. (B) If an energy isolating device is capable of being locked out, the employer's program shall use lockout, unless the employer can demonstrate that the use of a tagout system...

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

    NASA Technical Reports Server (NTRS)

    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. 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

  17. 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.

  18. Ultra-wideband signal generator based on cross gain modulation effect in a distributed feedback laser

    NASA Astrophysics Data System (ADS)

    Chen, Dalei; Wang, Rong; Xiang, Peng; Pu, Tao; Fang, Tao; Li, Yuandong; Su, Yang; Zheng, Jiling; Huang, Long; Zhu, Huatao; Huang, Jie

    2016-10-01

    In this paper, a novel scheme to generate ultra-wideband (UWB) signals based on cross-gain modulation (XGM) effect in a DFB laser is proposed and experimentally demonstrated, and the modulation and transmission of the UWB signals are also experimentally investigated. In the proposed system, a gain-switched laser (GSL) is used as master laser (ML) and the optical pulses from the ML are optically injected into a DFB laser, which is used as slave laser (SL). By proper system configuration, UWB monocycle, doublet or triplet UWB signals can be generated after the balanced photodiode (BPD) detection. Besides, other modulation formats can also be realized, such as on-off keying (OOK) and pulse amplitude modulation (PAM) by properly modulating the ML optical pulses. Finally, fiber transmission of the modulated UWB signals is experimentally investigated, and it is shown that the UWB signals can be well maintained after 40 km optical fiber transmission.

  19. 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.

  20. 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.

  1. Development of Power Supply System with Distributed Generators using Parallel Processing Method

    NASA Astrophysics Data System (ADS)

    Hirose, Kenichi; Takeda, Takashi; Okui, Yoshiaki; Yukita, Kazuto; Goto, Yasuyuki; Ichiyanagi, Katsuhiro; Matsumura, Toshiro

    This paper describes a novel power system which consists of distributed energy resources (DER) with a static switch at the point of common coupling. Usage of the static switch with a parallel processing control is a new application of line interactive type uninterruptible power supply (UPS). In recent years, various ways of design, operation, and control methods have been studied in order to find more effective ways to utilize renewable energy and to reduce impact for environment. One of features of a proposed power system can interconnect to existing utility grid without interruption. Electrical power distribution to the loads by the power system can be continued between the states of interconnection and isolate operation seamlessly. The novel power system has other benefits such as more efficiency, demand site management, easy to control power system inside, improvement of reliability for power distribution, the minimum requirement of protection relays for grid interconnection. The proposed power system has been operated with the actual loads of 20kW in the campus of the Aichi Institute of Technology since 2007.

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

    DTIC Science & Technology

    2015-07-01

    Pearl Harbor Hickam kVA kilo volt-amperes kVAR Kilo Volt-Amperes Reactive kW kilowatt kWHr kilowatt hour Li Ion lithium ion MCAS Marine Corps...support grid stability by providing transient power (real and reactive ); and support PV power transitions to maintain a stable islanded microgrid. The...PV solar array, whose inverter is configured to provide generator like operation, including volt-ampere reactive (VAR) support ( reactive power) for

  3. Assessment of ethanol-fueled IMHEX{reg_sign} fuel cell power plants in distributed generation

    SciTech Connect

    Woods, R.; Lefeld, J.

    1993-12-31

    Ethanol-fueled cell power plants presents several significant opportunities for the power generation industry. The potential exists to reduce pollution, help the nation shift from its dependence on imported fuels, reduce global warming, and strengthen the economy. Two important developments can be merged to create a clean, high-technology, bio-based energy system: the production of ethanol fuels and the application of fuel cell power plants. Utilization of ethanol will be in dual-fueled applications initially, and evolve toward the primary fuel as the need for renewable energy sources increase and the economic competitiveness improves. This assessment addresses the major issues of this proposed concept and outlines the benefits anticipated to the environment, US agriculture, energy supplies, and electric power customers. Economic and technical aspects of the concept are also reviewed. One of PSI Energy`s primary interests is the utilization of renewable fuels supplied by their customer base. The IMHEX{reg_sign} fuel cell is an advanced electric power generation technology currently under development by M-C Power. Commercial applications within the power generation industry are scheduled to begin during the late 1990s.

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. A New Efficient Method for Generating Conformations of Unfolded Proteins with Diverse Main-Chain Dihedral-Angle Distributions.

    PubMed

    Seki, Yasutaka; Shimbo, Yudai; Nonaka, Takamasa; Soda, Kunitsugu

    2011-07-12

    A new method for generating polypeptide-chain conformations has been developed for studying structural characteristics of unfolded proteins. It enables us to generate a large number of conformations very rapidly by avoiding atomic collisions efficiently with the use of main-chain dihedral-angle distributions derived from a crystal-structure database of proteins. In addition, combining main-chain dihedral-angle distributions for the amino acid residues incorporated in different secondary structures, we can obtain diverse conformational ensembles with different structural features. Structural characteristics of proteins denatured in high-concentration denaturant solution were analyzed by comparing predictions from this method with results from solution X-ray scattering (SXS) measurement. Analysis of the dependence of the mean square radius (Rsq) of protein on the number of residues and the shape of its Kratky profile has confirmed that the highly denaturing solvent serves as a good solvent in accordance with previous reports. It was also found that, in order for a conformational ensemble to reproduce experimental data, the percentage in which main-chain dihedral angles are found in the α region must be in the range of 20-40%. It agrees with studies on the (3)JHNα coupling constant using the multidimensional NMR method. These results confirm that our method for generating diverse conformations of polypeptide chains is very useful to the conformational analysis of unfolded protein, because it enables us to analyze comprehensively both of the local structural features obtained from NMR and the global ones obtained from SXS.

  9. 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.

  10. 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.

  11. 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 .

  12. 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

  13. 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.

  14. Optimal Energy Management of an Academic Building with Distributed Generation and Energy Storage Systems

    NASA Astrophysics Data System (ADS)

    Roldán-Blay, C.; Roldán-Porta, C.; Peñalvo-López, E.; Escrivá-Escrivá, G.

    2017-07-01

    In this paper, an optimisation algorithm is used to simulate the management of distributed energy resources in an academic building. This optimisation algorithm, called DEROP, consists of an iterative procedure reach a supply schedule with the minimum energy cost. The inputs to the algorithm are the demand forecast, the availability of each resource, the level of storage in energy storage systems and prices and efficiencies of each resource. With these data, the algorithm proposes the optimal schedule to minimise costs of energy supply. The main advantages of this algorithm are that it is fast, easy to be implemented in real buildings and flexible. The algorithm is simulated with real data to optimise management of distributed energy resources and energy storage systems in an academic building. The management of these resources is optimised for a tariff with hourly discrimination and for a tariff with no time restrictions. One of the main conclusions drawn from these simulations are that significant savings are obtained with this algorithm. Also, DEROP allows taking advantage of tariffs with hourly discrimination, even in an academic building with low night-time consumption in which, a priori, these tariffs are not profitable.

  15. High-power distributed Bragg reflector lasers for green-light generation

    NASA Astrophysics Data System (ADS)

    Hu, Martin H.; Nguyen, Hong Ky; Song, Kechang; Li, Yabo; Visovsky, Nick J.; Liu, Xingsheng; Nishiyama, Nobuhiko; Coleman, Sean; Hughes, Lawrence C., Jr.; Gollier, Jacques; Miller, William; Bhat, Raj; Zah, Chung-En

    2006-02-01

    We report on the design, fabrication and performance of high-power and high-modulation-speed 1060-nm DBR lasers for green-light emission by second harmonic generation. Single-spatial-mode and single-wavelength power more than 450 mW of 1060-nm wavelength was achieved with a 3-section DBR laser with non-absorbing DBR and phase sections created by an impurity-free quantum-well intermixing technique. A thermally-induced wavelength tuning of 2.4 nm and a carrier-induced wavelength tuning of -0.85 nm were obtained by injecting current into the DBR section. The green power as high as 104.6 mW was demonstrated by coupling the DBR laser output to a second-harmonic-generation waveguide. Measured rise/fall times of 0.2 ns for direct intensity modulation and 0.6 ns for wavelength modulation make the DBR lasers suitable for >=50-MHz green-light-modulation applications. The detrimental thermally-induced patterning effect and a differential-phase modulation scheme as a solution are discussed.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. Spatial distribution on high-order-harmonic generation of an H2+ molecule in intense laser fields

    NASA Astrophysics Data System (ADS)

    Zhang, Jun; Ge, Xin-Lei; Wang, Tian; Xu, Tong-Tong; Guo, Jing; Liu, Xue-Shen

    2015-07-01

    High-order-harmonic generation (HHG) for the H2 + molecule in a 3-fs, 800-nm few-cycle Gaussian laser pulse combined with a static field is investigated by solving the one-dimensional electronic and one-dimensional nuclear time-dependent Schrödinger equation within the non-Born-Oppenheimer approximation. The spatial distribution in HHG is demonstrated and the results present the recombination process of the electron with the two nuclei, respectively. The spatial distribution of the HHG spectra shows that there is little possibility of the recombination of the electron with the nuclei around the origin z =0 a.u. and equilibrium internuclear positions z =±1.3 a.u. This characteristic is irrelevant to laser parameters and is only attributed to the molecular structure. Furthermore, we investigate the time-dependent electron-nuclear wave packet and ionization probability to further explain the underlying physical mechanism.

  1. Optical key distribution system using atmospheric turbulence as the randomness generating function: classical optical protocol for information assurance

    NASA Astrophysics Data System (ADS)

    Drake, Marvin D.; Bas, Christophe F.; Gervais, David; Renda, Priscilla F.; Townsend, Daniel; Rushanan, Joseph J.; Francoeur, Joe; Donnangelo, Nick; Stenner, Michael D.

    2013-05-01

    We describe an experimental laboratory system that generates and distributes random binary sequence bit streams between two optical terminals (labeled Alice and Bob). The random binary sequence is generated through probing the optical channel of a turbulent atmosphere between the two terminals with coincident laser beams. The two laser beams experience differential phase delays while propagating through the atmospheric optical channel. The differential phase delays are detected and sampled at each terminal to yield raw random bit streams. The random bit streams are processed to remove bit errors and, through privacy amplification, to yield a bit stream known only to Alice and Bob. The same chaotic physical mechanism that provides randomness also provides confidentiality. The laboratory system yielded secret key bit rates of a few bits/second. For external optical channels over longer channel lengths with atmospheric turbulence levels, secret bit rates of 10 s of bits/second are predicted.

  2. 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.

  3. Co-generation and innovative heat storage systems in small-medium CSP plants for distributed energy production

    NASA Astrophysics Data System (ADS)

    Giaconia, Alberto; Montagnino, Fabio; Paredes, Filippo; Donato, Filippo; Caputo, Giampaolo; Mazzei, Domenico

    2017-06-01

    CSP technologies can be applied for distributed energy production, on small-medium plants (on the 1 MW scale), to satisfy the needs of local communities, buildings and districts. In this perspective, reliable, low-cost, and flexible small/medium multi-generative CSP plants should be developed. Four pilot plants have been built in four Mediterranean countries (Cyprus, Egypt, Jordan, and Italy) to demonstrate the approach. In this paper, the plant built in Italy is presented, with specific innovations applied in the linear Fresnel collector design and the Thermal Energy Storage (TES) system, based on a single the use of molten salts but specifically tailored for small scale plants.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Development of a Compound Distribution Markov Chain Model for Stochastic Generation of Rainfall with Long Term Persistence

    NASA Astrophysics Data System (ADS)

    Kamal Chowdhury, AFM; Lockart, Natalie; Willgoose, Garry; Kuczera, George

    2015-04-01

    One of the overriding issues in the rainfall simulation is the underestimation of observed rainfall variability in longer timescales (e.g. monthly, annual and multi-year), which usually results into under-estimation of reservoir reliability in urban water planning. This study has developed a Compound Distribution Markov Chain (CDMC) model for stochastic generation of daily rainfall. We used two parameters of Markov Chain process (transition probabilities of wet-to-wet and dry-to-dry days) for simulating rainfall occurrence and two parameters of gamma distribution (calculated from mean and standard deviation of wet-day rainfall) for simulating wet-day rainfall amounts. While two models with deterministic parameters underestimated long term variability, our investigation found that the long term variability of rainfall in the model is predominantly governed by the long term variability of gamma parameters, rather than the variability of Markov Chain parameters. Therefore, in the third approach, we developed the CDMC model with deterministic parameters of Markov Chain process, but stochastic parameters of gamma distribution by sampling the mean and standard deviation of wet-day rainfall from their log-normal and bivariate-normal distribution. We have found that the CDMC is able to replicate both short term and long term rainfall variability, when we calibrated the model at two sites in east coast of Australia using three types of daily rainfall data - (1) dynamically downscaled, 10 km resolution gridded data produced by NSW/ACT Regional Climate Modelling project, (2) 5 km resolution gridded data by Australian Water Availability Project and (3) point scale raingauge stations data by Bureau of Meteorology, Australia. We also examined the spatial variability of parameters and their link with local orography at our field site. The suitability of the model in runoff generation and urban reservoir-water simulation will be discussed.

  11. A new method for power generation and distribution in outer space

    SciTech Connect

    Bamberger, J.A.

    1989-09-01

    The power system is a major component of a space system's size, mass, technical complexity, and hence, cost. To date, space systems include the energy source as an integral part of the mission satellite. Potentially significant benefit could be realized by separating the energy source from the end-use system and transmitting the power via an energy beam (power beaming) (Coomes et al., 1989). This concept parallels the terrestrial central generating station and transmission grid. In this summary, the system components required for power beaming implementation are outlined and applied to a satellite for power beaming implementation are outlined and applied to a satellite constellation to demonstrate the feasibility of implementing power beaming in the next 20 years. 5 refs., 1 fig., 3 tabs.

  12. 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.

  13. 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.

  14. A fuzzy-based methodology for volt/var control on distribution systems containing dispersed wind generation

    NASA Astrophysics Data System (ADS)

    Black, Clifton R. M.

    This research focuses on voltage and reactive power control on the distribution system in an atmosphere of uncertainty. It also investigates the incorporation of wind turbines into load-flow analysis. It is widely recognized, that in practice, data are only known with finite accuracy and are hence, inexact in nature. In this research, fuzzy load-flow is used to handle this uncertainty. Fuzzy load-flow is based on fuzzy-set theory which has the ability to handle various forms of uncertainty including that from random variables. The fuzzy load flow technique [FLFT] presented in this dissertation, is different from the approach of other authors, in that it is more straightforward. It is based on fuzzy numbers and fuzzy arithmetic, and it calls for only one power-flow solution. The introduction of partial fuzzy arithmetic along with the use of fuzzy arithmetic and point-by-point calculations is significant. The result is a simple and fast technique. The proposed technique is suited for loosely meshed distribution systems with multiple sources. These attributes make this new approach quite attractive for application in today's distribution system which is characterized by the presence of distributed generators and meshes. The voltage and reactive power control problem is de-coupled into sub-problems characterized by the reaction speed of the different control devices. The sub-problem categories are "fast", "medium", and "slow", based on the frequency with which the control devices are adjusted. The control elements include transformer load tap changers (LTC), voltage regulators, and switched capacitors. Fuzzy models for these control devices are introduced and effectively demonstrated. There is a great demand for alternative sources of electric energy. In this research, a fuzzy model for the wind turbine generator is presented. The active power produced by the wind turbines and the reactive power absorbed are expressed as functions of the wind velocity. This research

  15. 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

  16. Internal wave generation by tidal flow over periodically and randomly distributed seamounts

    NASA Astrophysics Data System (ADS)

    Zhang, Likun; Buijsman, Maarten C.; Comino, Eva; Swinney, Harry L.

    2017-06-01

    We examine numerically the conversion of barotropic tidal energy into internal waves by flow over an isolated seamount and over systems of periodically and randomly distributed 1100 m tall seamounts with Gaussian profiles. The simulations use the Massachusetts Institute of Technology general circulation model (MITgcm) to calculate for an infinitely deep ocean the dependence of the energy conversion on seamount slope, seamount separation, tidal direction, and the size and aspect ratio of the simulation domain. For neighboring seamounts with a slope greater than the internal wave beam slope, wave interference reduces the conversion relative to that calculated for an isolated seamount, and relative to that predicted by linear theory for a seamount of slope less than the beam slope. The conversion by an individual seamount in a system of random seamounts separated by an average distance of 18 km is found to be suppressed by 16% relative to the conversion by an isolated seamount. This study provides insight into tidal conversion by ocean seamounts modeled as Gaussian mountains with slopes both smaller and larger than the beam slope. We conclude that the total energy conversion by all seamounts (peak height ≥1000 m) and knolls (peak height 500-1000 m), taking into account interference affects, is of the order of 1% of the total barotropic to baroclinic energy conversion in the oceans, which is about twice as large as previous estimates.

  17. 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.

  18. 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.

  19. 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.

  20. 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