WorldWideScience

Sample records for point source reduction

  1. Reduction Assessment of Agricultural Non-Point Source Pollutant Loading

    OpenAIRE

    Fu, YiCheng; Zang, Wenbin; Zhang, Jian; Wang, Hongtao; Zhang, Chunling; Shi, Wanli

    2018-01-01

    NPS (Non-point source) pollution has become a key impact element to watershed environment at present. With the development of technology, application of models to control NPS pollution has become a very common practice for resource management and Pollutant reduction control in the watershed scale of China. The SWAT (Soil and Water Assessment Tool) model is a semi-conceptual model, which was put forward to estimate pollutant production & the influences on water quantity-quality under different...

  2. Reduction of non-point source contaminants associated with road-deposited sediments by sweeping.

    Science.gov (United States)

    Kim, Do-Gun; Kang, Hee-Man; Ko, Seok-Oh

    2017-09-19

    Road-deposited sediments (RDS) on an expressway, residual RDS collected after sweeping, and RDS removed by means of sweeping were analyzed to evaluate the degree to which sweeping removed various non-point source contaminants. The total RDS load was 393.1 ± 80.3 kg/km and the RDS, residual RDS, and swept RDS were all highly polluted with organics, nutrients, and metals. Among the metals studied, Cu, Zn, Pb, Ni, Ca, and Fe were significantly enriched, and most of the contaminants were associated with particles within the size range from 63 μm to 2 mm. Sweeping reduced RDS and its associated contaminants by 33.3-49.1% on average. We also measured the biological oxygen demand (BOD) of RDS in the present work, representing to our knowledge the first time that this has been done; we found that RDS contains a significant amount of biodegradable organics and that the reduction of BOD by sweeping was higher than that of other contaminants. Significant correlations were found between the contaminants measured, indicating that the organics and the metals originated from both exhaust and non-exhaust particles. Meanwhile, the concentrations of Cu and Ni were higher in 63 μm-2 mm particles than in smaller particles, suggesting that some metals in RDS likely exist intrinsically in particles, rather than only as adsorbates on particle surfaces. Overall, the results in this study showed that sweeping to collect RDS can be a good alternative for reduction of contaminants in runoff.

  3. Photoacoustic Point Source

    International Nuclear Information System (INIS)

    Calasso, Irio G.; Craig, Walter; Diebold, Gerald J.

    2001-01-01

    We investigate the photoacoustic effect generated by heat deposition at a point in space in an inviscid fluid. Delta-function and long Gaussian optical pulses are used as sources in the wave equation for the displacement potential to determine the fluid motion. The linear sound-generation mechanism gives bipolar photoacoustic waves, whereas the nonlinear mechanism produces asymmetric tripolar waves. The salient features of the photoacoustic point source are that rapid heat deposition and nonlinear thermal expansion dominate the production of ultrasound

  4. Point Pollution Sources Dimensioning

    Directory of Open Access Journals (Sweden)

    Georgeta CUCULEANU

    2011-06-01

    Full Text Available In this paper a method for determining the main physical characteristics of the point pollution sources is presented. It can be used to find the main physical characteristics of them. The main physical characteristics of these sources are top inside source diameter and physical height. The top inside source diameter is calculated from gas flow-rate. For reckoning the physical height of the source one takes into account the relation given by the proportionality factor, defined as ratio between the plume rise and physical height of the source. The plume rise depends on the gas exit velocity and gas temperature. That relation is necessary for diminishing the environmental pollution when the production capacity of the plant varies, in comparison with the nominal one.

  5. Evaluation of non-point source pollution reduction by applying best management practices using a SWAT model and QuickBird high resolution satellite imagery.

    Science.gov (United States)

    Lee, MiSeon; Park, GeunAe; Park, MinJi; Park, JongYoon; Lee, JiWan; Kim, SeongJoon

    2010-01-01

    This study evaluated the reduction effect of non-point source pollution by applying best management practices (BMPs) to a 1.21 km2 small agricultural watershed using a SWAT (Soil and Water Assessment Tool) model. Two meter QuickBird land use data were prepared for the watershed. The SWAT was calibrated and validated using daily streamflow and monthly water quality (total phosphorus (TP), total nitrogen (TN), and suspended solids (SS)) records from 1999 to 2000 and from 2001 to 2002. The average Nash and Sutcliffe model efficiency was 0.63 for the streamflow and the coefficients of determination were 0.88, 0.72, and 0.68 for SS, TN, and TP, respectively. Four BMP scenarios viz. the application of vegetation filter strip and riparian buffer system, the regulation of Universal Soil Loss Equation P factor, and the fertilizing control amount for crops were applied and analyzed.

  6. Source splitting via the point source method

    International Nuclear Information System (INIS)

    Potthast, Roland; Fazi, Filippo M; Nelson, Philip A

    2010-01-01

    We introduce a new algorithm for source identification and field splitting based on the point source method (Potthast 1998 A point-source method for inverse acoustic and electromagnetic obstacle scattering problems IMA J. Appl. Math. 61 119–40, Potthast R 1996 A fast new method to solve inverse scattering problems Inverse Problems 12 731–42). The task is to separate the sound fields u j , j = 1, ..., n of n element of N sound sources supported in different bounded domains G 1 , ..., G n in R 3 from measurements of the field on some microphone array—mathematically speaking from the knowledge of the sum of the fields u = u 1 + ... + u n on some open subset Λ of a plane. The main idea of the scheme is to calculate filter functions g 1 ,…, g n , n element of N, to construct u l for l = 1, ..., n from u| Λ in the form u l (x) = ∫ Λ g l,x (y)u(y)ds(y), l=1,... n. (1) We will provide the complete mathematical theory for the field splitting via the point source method. In particular, we describe uniqueness, solvability of the problem and convergence and stability of the algorithm. In the second part we describe the practical realization of the splitting for real data measurements carried out at the Institute for Sound and Vibration Research at Southampton, UK. A practical demonstration of the original recording and the splitting results for real data is available online

  7. Point-source inversion techniques

    Science.gov (United States)

    Langston, Charles A.; Barker, Jeffrey S.; Pavlin, Gregory B.

    1982-11-01

    A variety of approaches for obtaining source parameters from waveform data using moment-tensor or dislocation point source models have been investigated and applied to long-period body and surface waves from several earthquakes. Generalized inversion techniques have been applied to data for long-period teleseismic body waves to obtain the orientation, time function and depth of the 1978 Thessaloniki, Greece, event, of the 1971 San Fernando event, and of several events associated with the 1963 induced seismicity sequence at Kariba, Africa. The generalized inversion technique and a systematic grid testing technique have also been used to place meaningful constraints on mechanisms determined from very sparse data sets; a single station with high-quality three-component waveform data is often sufficient to discriminate faulting type (e.g., strike-slip, etc.). Sparse data sets for several recent California earthquakes, for a small regional event associated with the Koyna, India, reservoir, and for several events at the Kariba reservoir have been investigated in this way. Although linearized inversion techniques using the moment-tensor model are often robust, even for sparse data sets, there are instances where the simplifying assumption of a single point source is inadequate to model the data successfully. Numerical experiments utilizing synthetic data and actual data for the 1971 San Fernando earthquake graphically demonstrate that severe problems may be encountered if source finiteness effects are ignored. These techniques are generally applicable to on-line processing of high-quality digital data, but source complexity and inadequacy of the assumed Green's functions are major problems which are yet to be fully addressed.

  8. Calcareous Fens - Source Feature Points

    Data.gov (United States)

    Minnesota Department of Natural Resources — Pursuant to the provisions of Minnesota Statutes, section 103G.223, this database contains points that represent calcareous fens as defined in Minnesota Rules, part...

  9. Unidentified point sources in the IRAS minisurvey

    Science.gov (United States)

    Houck, J. R.; Soifer, B. T.; Neugebauer, G.; Beichman, C. A.; Aumann, H. H.; Clegg, P. E.; Gillett, F. C.; Habing, H. J.; Hauser, M. G.; Low, F. J.

    1984-01-01

    Nine bright, point-like 60 micron sources have been selected from the sample of 8709 sources in the IRAS minisurvey. These sources have no counterparts in a variety of catalogs of nonstellar objects. Four objects have no visible counterparts, while five have faint stellar objects visible in the error ellipse. These sources do not resemble objects previously known to be bright infrared sources.

  10. Harm reduction services as a point-of-entry to and source of end-of-life care and support for homeless and marginally housed persons who use alcohol and/or illicit drugs: a qualitative analysis.

    Science.gov (United States)

    McNeil, Ryan; Guirguis-Younger, Manal; Dilley, Laura B; Aubry, Tim D; Turnbull, Jeffrey; Hwang, Stephen W

    2012-05-17

    Homeless and marginally housed persons who use alcohol and/or illicit drugs often have end-of-life care needs that go unmet due to barriers that they face to accessing end-of-life care services. Many homeless and marginally housed persons who use these substances must therefore rely upon alternate sources of end-of-life care and support. This article explores the role of harm reduction services in end-of-life care services delivery to homeless and marginally housed persons who use alcohol and/or illicit drugs. A qualitative case study design was used to explore end-of-life care services delivery to homeless and marginally housed persons in six Canadian cities. A key objective was to explore the role of harm reduction services. 54 health and social services professionals participated in semi-structured qualitative interviews. All participants reported that they provided care and support to this population at end-of-life. Harm reduction services (e.g., syringe exchange programs, managed alcohol programs, etc.) were identified as a critical point-of-entry to and source of end-of-life care and support for homeless and marginally housed persons who use alcohol and/or illicit drugs. Where possible, harm reduction services facilitated referrals to end-of-life care services for this population. Harm reduction services also provided end-of-life care and support when members of this population were unable or unwilling to access end-of-life care services, thereby improving quality-of-life and increasing self-determination regarding place-of-death. While partnerships between harm reduction programs and end-of-life care services are identified as one way to improve access, it is noted that more comprehensive harm reduction services might be needed in end-of-life care settings if they are to engage this underserved population.

  11. UHE point source survey at Cygnus experiment

    International Nuclear Information System (INIS)

    Lu, X.; Yodh, G.B.; Alexandreas, D.E.; Allen, R.C.; Berley, D.; Biller, S.D.; Burman, R.L.; Cady, R.; Chang, C.Y.; Dingus, B.L.; Dion, G.M.; Ellsworth, R.W.; Gilra, M.K.; Goodman, J.A.; Haines, T.J.; Hoffman, C.M.; Kwok, P.; Lloyd-Evans, J.; Nagle, D.E.; Potter, M.E.; Sandberg, V.D.; Stark, M.J.; Talaga, R.L.; Vishwanath, P.R.; Zhang, W.

    1991-01-01

    A new method of searching for UHE point source has been developed. With a data sample of 150 million events, we have surveyed the sky for point sources over 3314 locations (1.4 degree <δ<70.4 degree). It was found that their distribution is consistent with a random fluctuation. In addition, fifty two known potential sources, including pulsars and binary x-ray sources, were studied. The source with the largest positive excess is the Crab Nebula. An excess of 2.5 sigma above the background is observed in a bin of 2.3 degree by 2.5 degree in declination and right ascension respectively

  12. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  13. Pseudo-dynamic source modelling with 1-point and 2-point statistics of earthquake source parameters

    KAUST Repository

    Song, S. G.; Dalguer, L. A.; Mai, Paul Martin

    2013-01-01

    statistical framework that governs the finite-fault rupture process with 1-point and 2-point statistics of source parameters in order to quantify the variability of finite source models for future scenario events. We test this method by extracting 1-point

  14. OH masers associated with IRAS point sources

    NARCIS (Netherlands)

    Masheder, MRW; Cohen, RJ; Martin-Hernandez, NL; Migenes,; Reid, MJ

    2002-01-01

    We report a search for masers from the Lambda-doublet of the ground-state of OH at 18cm, carried out with the Jodrell Bank Lovell Telescope and with the 25m Dwingeloo telescope. All objects north of delta = -20degrees which appear in the IRAS Point Source Catalog with fluxes > 1000 Jy at 60mum and

  15. Isotropic irradiation of detectors from point sources

    DEFF Research Database (Denmark)

    Aage, Helle Karina

    1997-01-01

    NaI(Tl) scintillator detectors have been exposed to gamma rays from 8 different point sources from different directions. Background and backscatter of gamma-rays from the surroundings have been subtracted in order to produce clean spectra. By adding spectra obtained from exposures from different ...

  16. Pseudo-dynamic source modelling with 1-point and 2-point statistics of earthquake source parameters

    KAUST Repository

    Song, S. G.

    2013-12-24

    Ground motion prediction is an essential element in seismic hazard and risk analysis. Empirical ground motion prediction approaches have been widely used in the community, but efficient simulation-based ground motion prediction methods are needed to complement empirical approaches, especially in the regions with limited data constraints. Recently, dynamic rupture modelling has been successfully adopted in physics-based source and ground motion modelling, but it is still computationally demanding and many input parameters are not well constrained by observational data. Pseudo-dynamic source modelling keeps the form of kinematic modelling with its computational efficiency, but also tries to emulate the physics of source process. In this paper, we develop a statistical framework that governs the finite-fault rupture process with 1-point and 2-point statistics of source parameters in order to quantify the variability of finite source models for future scenario events. We test this method by extracting 1-point and 2-point statistics from dynamically derived source models and simulating a number of rupture scenarios, given target 1-point and 2-point statistics. We propose a new rupture model generator for stochastic source modelling with the covariance matrix constructed from target 2-point statistics, that is, auto- and cross-correlations. Our sensitivity analysis of near-source ground motions to 1-point and 2-point statistics of source parameters provides insights into relations between statistical rupture properties and ground motions. We observe that larger standard deviation and stronger correlation produce stronger peak ground motions in general. The proposed new source modelling approach will contribute to understanding the effect of earthquake source on near-source ground motion characteristics in a more quantitative and systematic way.

  17. Modeling the contribution of point sources and non-point sources to Thachin River water pollution.

    Science.gov (United States)

    Schaffner, Monika; Bader, Hans-Peter; Scheidegger, Ruth

    2009-08-15

    Major rivers in developing and emerging countries suffer increasingly of severe degradation of water quality. The current study uses a mathematical Material Flow Analysis (MMFA) as a complementary approach to address the degradation of river water quality due to nutrient pollution in the Thachin River Basin in Central Thailand. This paper gives an overview of the origins and flow paths of the various point- and non-point pollution sources in the Thachin River Basin (in terms of nitrogen and phosphorus) and quantifies their relative importance within the system. The key parameters influencing the main nutrient flows are determined and possible mitigation measures discussed. The results show that aquaculture (as a point source) and rice farming (as a non-point source) are the key nutrient sources in the Thachin River Basin. Other point sources such as pig farms, households and industries, which were previously cited as the most relevant pollution sources in terms of organic pollution, play less significant roles in comparison. This order of importance shifts when considering the model results for the provincial level. Crosschecks with secondary data and field studies confirm the plausibility of our simulations. Specific nutrient loads for the pollution sources are derived; these can be used for a first broad quantification of nutrient pollution in comparable river basins. Based on an identification of the sensitive model parameters, possible mitigation scenarios are determined and their potential to reduce the nutrient load evaluated. A comparison of simulated nutrient loads with measured nutrient concentrations shows that nutrient retention in the river system may be significant. Sedimentation in the slow flowing surface water network as well as nitrogen emission to the air from the warm oxygen deficient waters are certainly partly responsible, but also wetlands along the river banks could play an important role as nutrient sinks.

  18. EDF source term reduction project main outcomes and further developments

    International Nuclear Information System (INIS)

    Ranchoux, Gilles; Bonnefon, Julien; Benfarah, Moez; Wintergerst Matthieu; Gressier, Frederic; Leclercq, Stephanie

    2012-09-01

    The dose reduction is a strategic purpose for EDF in link with the stakes of, nuclear acceptability, respect of regulation and productivity gains. This consists not only in improving the reactor shutdown organization (time spent in control area, biological shielding,...) but also in improving the radiological state of the unit and the efficiency of the source term reduction operations. Since 2003, EDF has been running an innovative project called 'Source Term Reduction' federating the different EDF research and engineering centers in order to: - participate to the long term view about Radiological Protection issues (international feedback analyses), - develop contamination prediction tools (OSCAR software) suitable for the industrial needs (operating units and EPR design), - develop scientific models useful for the understanding of contamination mechanisms to support the strategic decision processes, - carry on with updating and analyzing of contamination measurements feedback in corrosion products (EMECC and CZT campaigns), - carry on with the operational support at short or middle term by optimizing startup and shutdown processes, pre-oxidation or and by improving purification efficiency or material characteristics. This paper will show in a first part the main 2011 results in occupational exposure (collective and individual dose, RCS index...). In a second part, an overview of the main EDF outcomes of the last 3 years in the field of source term reduction will be presented. Future developments extended to contamination issues in EDF NPPs will be also pointed out in this paper. (authors)

  19. Assessment of the impact of point source pollution from the ...

    African Journals Online (AJOL)

    Assessment of the impact of point source pollution from the Keiskammahoek Sewage ... Water SA. Journal Home · ABOUT THIS JOURNAL · Advanced Search ... Also, significant pollution of the receiving Keiskamma River was indicated for ...

  20. Effect of point source and heterogeneity on the propagation of ...

    African Journals Online (AJOL)

    user

    propagation of Love waves due to point source in a homogeneous layer overlying a ...... The dispersion equation of SH waves will be obtained by equating to zero the ..... He was Awarded Atomic Energy Fellowship by the Government of India.

  1. Point source reconstruction principle of linear inverse problems

    International Nuclear Information System (INIS)

    Terazono, Yasushi; Matani, Ayumu; Fujimaki, Norio; Murata, Tsutomu

    2010-01-01

    Exact point source reconstruction for underdetermined linear inverse problems with a block-wise structure was studied. In a block-wise problem, elements of a source vector are partitioned into blocks. Accordingly, a leadfield matrix, which represents the forward observation process, is also partitioned into blocks. A point source is a source having only one nonzero block. An example of such a problem is current distribution estimation in electroencephalography and magnetoencephalography, where a source vector represents a vector field and a point source represents a single current dipole. In this study, the block-wise norm, a block-wise extension of the l p -norm, was defined as the family of cost functions of the inverse method. The main result is that a set of three conditions was found to be necessary and sufficient for block-wise norm minimization to ensure exact point source reconstruction for any leadfield matrix that admit such reconstruction. The block-wise norm that satisfies the conditions is the sum of the cost of all the observations of source blocks, or in other words, the block-wisely extended leadfield-weighted l 1 -norm. Additional results are that minimization of such a norm always provides block-wisely sparse solutions and that its solutions form cones in source space

  2. 2011 Radioactive Materials Usage Survey for Unmonitored Point Sources

    Energy Technology Data Exchange (ETDEWEB)

    Sturgeon, Richard W. [Los Alamos National Laboratory

    2012-06-27

    This report provides the results of the 2011 Radioactive Materials Usage Survey for Unmonitored Point Sources (RMUS), which was updated by the Environmental Protection (ENV) Division's Environmental Stewardship (ES) at Los Alamos National Laboratory (LANL). ES classifies LANL emission sources into one of four Tiers, based on the potential effective dose equivalent (PEDE) calculated for each point source. Detailed descriptions of these tiers are provided in Section 3. The usage survey is conducted annually; in odd-numbered years the survey addresses all monitored and unmonitored point sources and in even-numbered years it addresses all Tier III and various selected other sources. This graded approach was designed to ensure that the appropriate emphasis is placed on point sources that have higher potential emissions to the environment. For calendar year (CY) 2011, ES has divided the usage survey into two distinct reports, one covering the monitored point sources (to be completed later this year) and this report covering all unmonitored point sources. This usage survey includes the following release points: (1) all unmonitored sources identified in the 2010 usage survey, (2) any new release points identified through the new project review (NPR) process, and (3) other release points as designated by the Rad-NESHAP Team Leader. Data for all unmonitored point sources at LANL is stored in the survey files at ES. LANL uses this survey data to help demonstrate compliance with Clean Air Act radioactive air emissions regulations (40 CFR 61, Subpart H). The remainder of this introduction provides a brief description of the information contained in each section. Section 2 of this report describes the methods that were employed for gathering usage survey data and for calculating usage, emissions, and dose for these point sources. It also references the appropriate ES procedures for further information. Section 3 describes the RMUS and explains how the survey results are

  3. Concept for Risk-based Prioritisation of Point Sources

    DEFF Research Database (Denmark)

    Overheu, N.D.; Troldborg, Mads; Tuxen, N.

    2010-01-01

    estimates on a local scale from all the sources, and 3D catchment-scale fate and transport modelling. It handles point sources at various knowledge levels and accounts for uncertainties. The tool estimates the impacts on the water supply in the catchment and provides an overall prioritisation of the sites...

  4. Induced Temporal Signatures for Point-Source Detection

    International Nuclear Information System (INIS)

    Stephens, Daniel L.; Runkle, Robert C.; Carlson, Deborah K.; Peurrung, Anthony J.; Seifert, Allen; Wyatt, Cory R.

    2005-01-01

    Detection of radioactive point-sized sources is inherently divided into two regimes encompassing stationary and moving detectors. The two cases differ in their treatment of background radiation and its influence on detection sensitivity. In the stationary detector case the statistical fluctuation of the background determines the minimum detectable quantity. In the moving detector case the detector may be subjected to widely and irregularly varying background radiation, as a result of geographical and environmental variation. This significant systematic variation, in conjunction with the statistical variation of the background, requires a conservative threshold to be selected to yield the same false-positive rate as the stationary detection case. This results in lost detection sensitivity for real sources. This work focuses on a simple and practical modification of the detector geometry that increase point-source recognition via a distinctive temporal signature. A key part of this effort is the integrated development of both detector geometries that induce a highly distinctive signature for point sources and the development of statistical algorithms able to optimize detection of this signature amidst varying background. The identification of temporal signatures for point sources has been demonstrated and compared with the canonical method showing good results. This work demonstrates that temporal signatures are efficient at increasing point-source discrimination in a moving detector system

  5. X pinch a point x-ray source

    International Nuclear Information System (INIS)

    Garg, A.B.; Rout, R.K.; Shyam, A.; Srinivasan, M.

    1993-01-01

    X ray emission from an X pinch, a point x-ray source has been studied using a pin-hole camera by a 30 kV, 7.2 μ F capacitor bank. The wires of different material like W, Mo, Cu, S.S.(stainless steel) and Ti were used. Molybdenum pinch gives the most intense x-rays and stainless steel gives the minimum intensity x-rays for same bank energy (∼ 3.2 kJ). Point x-ray source of size (≤ 0.5 mm) was observed using pin hole camera. The size of the source is limited by the size of the pin hole camera. The peak current in the load is approximately 150 kA. The point x-ray source could be useful in many fields like micro lithography, medicine and to study the basic physics of high Z plasmas. (author). 4 refs., 3 figs

  6. Very Luminous X-ray Point Sources in Starburst Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Ptak, A.; Weaver, K. A.; Strickland, D.

    Extranuclear X-ray point sources in external galaxies with luminosities above 1039.0 erg/s are quite common in elliptical, disk and dwarf galaxies, with an average of ~ 0.5 and dwarf galaxies, with an average of ~0.5 sources per galaxy. These objects may be a new class of object, perhaps accreting intermediate-mass black holes, or beamed stellar mass black hole binaries. Starburst galaxies tend to have a larger number of these intermediate-luminosity X-ray objects (IXOs), as well as a large number of lower-luminosity (1037 - 1039 erg/s) point sources. These point sources dominate the total hard X-ray emission in starburst galaxies. We present a review of both types of objects and discuss possible schemes for their formation.

  7. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...

  8. On the point-source approximation of earthquake dynamics

    Directory of Open Access Journals (Sweden)

    Andrea Bizzarri

    2014-06-01

    Full Text Available The focus on the present study is on the point-source approximation of a seismic source. First, we compare the synthetic motions on the free surface resulting from different analytical evolutions of the seismic source (the Gabor signal (G, the Bouchon ramp (B, the Cotton and Campillo ramp (CC, the Yoffe function (Y and the Liu and Archuleta function (LA. Our numerical experiments indicate that the CC and the Y functions produce synthetics with larger oscillations and correspondingly they have a higher frequency content. Moreover, the CC and the Y functions tend to produce higher peaks in the ground velocity (roughly of a factor of two. We have also found that the falloff at high frequencies is quite different: it roughly follows ω−2 in the case of G and LA functions, it decays more faster than ω−2 for the B function, while it is slow than ω−1 for both the CC and the Y solutions. Then we perform a comparison of seismic waves resulting from 3-D extended ruptures (both supershear and subshear obeying to different governing laws against those from a single point-source having the same features. It is shown that the point-source models tend to overestimate the ground motions and that they completely miss the Mach fronts emerging from the supershear transition process. When we compare the extended fault solutions against a multiple point-sources model the agreement becomes more significant, although relevant discrepancies still persist. Our results confirm that, and more importantly quantify how, the point-source approximation is unable to adequately describe the radiation emitted during a real world earthquake, even in the most idealized case of planar fault with homogeneous properties and embedded in a homogeneous, perfectly elastic medium.

  9. Localization of Point Sources for Poisson Equation using State Observers

    KAUST Repository

    Majeed, Muhammad Usman

    2016-08-09

    A method based On iterative observer design is presented to solve point source localization problem for Poisson equation with riven boundary data. The procedure involves solution of multiple boundary estimation sub problems using the available Dirichlet and Neumann data from different parts of the boundary. A weighted sum of these solution profiles of sub-problems localizes point sources inside the domain. Method to compute these weights is also provided. Numerical results are presented using finite differences in a rectangular domain. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

  10. Localization of Point Sources for Poisson Equation using State Observers

    KAUST Repository

    Majeed, Muhammad Usman; Laleg-Kirati, Taous-Meriem

    2016-01-01

    A method based On iterative observer design is presented to solve point source localization problem for Poisson equation with riven boundary data. The procedure involves solution of multiple boundary estimation sub problems using the available Dirichlet and Neumann data from different parts of the boundary. A weighted sum of these solution profiles of sub-problems localizes point sources inside the domain. Method to compute these weights is also provided. Numerical results are presented using finite differences in a rectangular domain. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

  11. Search for high energy cosmic neutrino point sources with ANTARES

    International Nuclear Information System (INIS)

    Halladjian, G.

    2010-01-01

    The aim of this thesis is the search for high energy cosmic neutrinos emitted by point sources with the ANTARES neutrino telescope. The detection of high energy cosmic neutrinos can bring answers to important questions such as the origin of cosmic rays and the γ-rays emission processes. In the first part of the thesis, the neutrino flux emitted by galactic and extragalactic sources and the number of events which can be detected by ANTARES are estimated. This study uses the measured γ-ray spectra of known sources taking into account the γ-ray absorption by the extragalactic background light. In the second part of the thesis, the absolute pointing of the ANTARES telescope is evaluated. Being located at a depth of 2475 m in sea water, the orientation of the detector is determined by an acoustic positioning system which relies on low and high frequency acoustic waves measurements between the sea surface and the bottom. The third part of the thesis is a search for neutrino point sources in the ANTARES data. The search algorithm is based on a likelihood ratio maximization method. It is used in two search strategies; 'the candidate sources list strategy' and 'the all sky search strategy'. Analysing 2007+2008 data, no discovery is made and the world's best upper limits on neutrino fluxes from various sources in the Southern sky are established. (author)

  12. Clinical Validation of Point-Source Corneal Topography in Keratoplasty

    NARCIS (Netherlands)

    Vrijling, A C L; Braaf, B.; Snellenburg, J.J.; de Lange, F.; Zaal, M.J.W.; van der Heijde, G.L.; Sicam, V.A.D.P.

    2011-01-01

    Purpose. To validate the clinical performance of point-source corneal topography (PCT) in postpenetrating keratoplasty (PKP) eyes and to compare it with conventional Placido-based topography. Methods. Corneal elevation maps of the anterior corneal surface were obtained from 20 post-PKP corneas using

  13. Identifying populations at risk from environmental contamination from point sources

    OpenAIRE

    Williams, F; Ogston, S

    2002-01-01

    Objectives: To compare methods for defining the population at risk from a point source of air pollution. A major challenge for environmental epidemiology lies in correctly identifying populations at risk from exposure to environmental pollutants. The complexity of today's environment makes it essential that the methods chosen are accurate and sensitive.

  14. Source Reduction Effectiveness at Fuel Contaminated Sites, Technical Summary Report

    National Research Council Canada - National Science Library

    2000-01-01

    This report assesses the degree to which various types or engineered source-reduction efforts at selected fuel-contaminated sites have resulted in decreasing concentrations of fuel constituents dissolved in groundwater...

  15. Research on point source simulating the γ-ray detection efficiencies of stander source

    International Nuclear Information System (INIS)

    Tian Zining; Jia Mingyan; Shen Maoquan; Yang Xiaoyan; Cheng Zhiwei

    2010-01-01

    For φ 75 mm x 25 mm sample, the full energy peak efficiencies on different heights of sample radius were obtained using the point sources, and the function parameters about the full energy peak efficiencies of point sources based on radius was fixed. The 59.54 keV γ-ray, 661.66 keV γ-ray, 1173.2 keV γ-ray, 1332.5 keV γ-ray detection efficiencies on different height of samples were obtained, based on the full energy peak efficiencies of point sources and its height, and the function parameters about the full energy peak efficiencies of surface sources based on sample height was fixed. The detection efficiency of (75 mm x 25 mm calibration source can be obtained by integrality, the detection efficiencies simulated by point sources are consistent with the results of stander source in 10%. Therefore, the calibration method of stander source can be substituted by the point source simulation method, and it tis feasible when there is no stander source.) (authors)

  16. Point source identification in nonlinear advection–diffusion–reaction systems

    International Nuclear Information System (INIS)

    Mamonov, A V; Tsai, Y-H R

    2013-01-01

    We consider a problem of identification of point sources in time-dependent advection–diffusion systems with a nonlinear reaction term. The linear counterpart of the problem in question can be reduced to solving a system of nonlinear algebraic equations via the use of adjoint equations. We extend this approach by constructing an algorithm that solves the problem iteratively to account for the nonlinearity of the reaction term. We study the question of improving the quality of source identification by adding more measurements adaptively using the solution obtained previously with a smaller number of measurements. (paper)

  17. Incentive aspects of point implementation of greenhouse gas reduction

    International Nuclear Information System (INIS)

    Michaelowa, A.

    1996-01-01

    The costs of a national climate policy instruments can be reduced if a reduction of greenhouse gas emission achieved abroad can be credited to a national target. Reductions carried through by agents of one country in another country are called Joint Implementation and have been a major topic in the negotiations on the UN Framework Convention on Climate Change. The first Conference of the parties in Berlin decided that the concept should be tested in a pilot phase without crediting. To induce private investments in Joint Implementation projects, primary instruments such as emission taxes, subsidies, tradeable emission rights or regulation are a necessary condition. Tax concessions, subsidies, additional emission rights or relaxation of regulation act as incentives. These must be proportional to the emission reduction achieved through the projects. Tax concessions and subsidies are preferable to other instruments for efficiency reasons. Examples are given for calculating tax concessions on a range of projects, including the installation of new boilers at a foreign power plant, the building of a new lignite power plant abroad, and the replacement of a coal-fired power plant with a hydroelectric power plant. 18 refs., 7 figs., 1 tab

  18. Point sources and multipoles in inverse scattering theory

    CERN Document Server

    Potthast, Roland

    2001-01-01

    Over the last twenty years, the growing availability of computing power has had an enormous impact on the classical fields of direct and inverse scattering. The study of inverse scattering, in particular, has developed rapidly with the ability to perform computational simulations of scattering processes and led to remarkable advances in a range of applications, from medical imaging and radar to remote sensing and seismic exploration. Point Sources and Multipoles in Inverse Scattering Theory provides a survey of recent developments in inverse acoustic and electromagnetic scattering theory. Focusing on methods developed over the last six years by Colton, Kirsch, and the author, this treatment uses point sources combined with several far-reaching techniques to obtain qualitative reconstruction methods. The author addresses questions of uniqueness, stability, and reconstructions for both two-and three-dimensional problems.With interest in extracting information about an object through scattered waves at an all-ti...

  19. Diffusion from a point source in an urban atmosphere

    International Nuclear Information System (INIS)

    Essa, K.S.M.; El-Otaify, M.S.

    2005-01-01

    In the present paper, a model for the diffusion of material from a point source in an urban atmosphere is incorporated. The plume is assumed to have a well-defined edge at which the concentration falls to zero. The vertical wind shear is estimated using logarithmic law, by employing most of the available techniques of stability categories. The concentrations estimated from the model were compared favorably with the field observations of other investigators

  20. Is a wind turbine a point source? (L).

    Science.gov (United States)

    Makarewicz, Rufin

    2011-02-01

    Measurements show that practically all noise of wind turbine noise is produced by turbine blades, sometimes a few tens of meters long, despite that the model of a point source located at the hub height is commonly used. The plane of rotating blades is the critical location of the receiver because the distances to the blades are the shortest. It is shown that such location requires certain condition to be met. The model is valid far away from the wind turbine as well.

  1. Pulsewidth-modulated 2-source neutral-point-clamped inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chang; Gao, Feng

    2007-01-01

    This paper presents the careful integration of a newly proposed Z-source topological concept to the basic neutral-point-clamped (NPC) inverter topology for designing a three-level inverter with both voltage-buck and voltage-boost capabilities. The designed Z-source NPC inverter uses two unique X......-shaped inductance-capacitance (LC) impedance networks that are connected between two isolated dc input power sources and its inverter circuitry for boosting its AC output voltage. Through the design of an appropriate pulsewidth-modulation (PWM) algorithm, the two impedance networks can be short......-circuited sequentially (without shooting through the inverter full DC link) for implementing the ldquonearest-three-vectorrdquo modulation principle with minimized harmonic distortion and device commutations per half carrier cycle while performing voltage boosting. With only a slight modification to the inverter PWM...

  2. Spatiotemporal patterns of non-point source nitrogen loss in an agricultural catchment

    Directory of Open Access Journals (Sweden)

    Jian-feng Xu

    2016-04-01

    Full Text Available Non-point source nitrogen loss poses a risk to sustainable aquatic ecosystems. However, non-point sources, as well as impaired river segments with high nitrogen concentrations, are difficult to monitor and regulate because of their diffusive nature, budget constraints, and resource deficiencies. For the purpose of catchment management, the Bayesian maximum entropy approach and spatial regression models have been used to explore the spatiotemporal patterns of non-point source nitrogen loss. In this study, a total of 18 sampling sites were selected along the river network in the Hujiashan Catchment. Over the time period of 2008–2012, water samples were collected 116 times at each site and analyzed for non-point source nitrogen loss. The morphometric variables and soil drainage of different land cover types were studied and considered potential factors affecting nitrogen loss. The results revealed that, compared with the approach using the Euclidean distance, the Bayesian maximum entropy approach using the river distance led to an appreciable 10.1% reduction in the estimation error, and more than 53.3% and 44.7% of the river network in the dry and wet seasons, respectively, had a probability of non-point source nitrogen impairment. The proportion of the impaired river segments exhibited an overall decreasing trend in the study catchment from 2008 to 2012, and the reduction in the wet seasons was greater than that in the dry seasons. High nitrogen concentrations were primarily found in the downstream reaches and river segments close to the residential lands. Croplands and residential lands were the dominant factors affecting non-point source nitrogen loss, and explained up to 70.7% of total nitrogen in the dry seasons and 54.7% in the wet seasons. A thorough understanding of the location of impaired river segments and the dominant factors affecting total nitrogen concentration would have considerable importance for catchment management.

  3. California Air Resources board's mobil source emission reduction credit guidelines

    International Nuclear Information System (INIS)

    Dunwoody Lentz, C.; Werner, B.

    1993-01-01

    The California Air Resources Board has developed guidance for the generation and use of mobil source emission reduction credits. Mobil source credits can be used to improve air quality, or to mitigate increases in emissions associated with industrial and non-industrial sources. They are created by programs which reduce mobile source emission beyond the reductions required by federal, state, and local laws or air quality attainment plans. Significant amounts of credit can be generated by some types of programs which reduce mobile source emissions of oxides of nitrogen (NO x ) and reactive organic gases (ROG). Mobile source credit programs must be carefully structured to ensure that emission reductions are real, accurately quantified, enforceable, and have a defined life. Three potentially feasible programs for the creation of mobile source credits include accelerated retirement of older vehicles, purchase of low-emission buses, and purchase of zero-emission vehicles. These programs are evaluated for their ability to generate credit and to assess their cost effectiveness. Based on the examples presented, two methods of generating mobile source credits, the accelerated retirement of older vehicles and the purchase of low-emission buses, appear to be cost-effective when compared to other emission control measures

  4. Scattering and absorption of particles emitted by a point source in a cluster of point scatterers

    International Nuclear Information System (INIS)

    Liljequist, D.

    2012-01-01

    A theory for the scattering and absorption of particles isotropically emitted by a point source in a cluster of point scatterers is described and related to the theory for the scattering of an incident particle beam. The quantum mechanical probability of escape from the cluster in different directions is calculated, as well as the spatial distribution of absorption events within the cluster. A source strength renormalization procedure is required. The average quantum scattering in clusters with randomly shifting scatterer positions is compared to trajectory simulation with the aim of studying the validity of the trajectory method. Differences between the results of the quantum and trajectory methods are found primarily for wavelengths larger than the average distance between nearest neighbour scatterers. The average quantum results include, for example, a local minimum in the number of absorption events at the location of the point source and interference patterns in the angle-dependent escape probability as well as in the distribution of absorption events. The relative error of the trajectory method is in general, though not generally, of similar magnitude as that obtained for beam scattering.

  5. Open-Source Automated Mapping Four-Point Probe

    Directory of Open Access Journals (Sweden)

    Handy Chandra

    2017-01-01

    Full Text Available Scientists have begun using self-replicating rapid prototyper (RepRap 3-D printers to manufacture open source digital designs of scientific equipment. This approach is refined here to develop a novel instrument capable of performing automated large-area four-point probe measurements. The designs for conversion of a RepRap 3-D printer to a 2-D open source four-point probe (OS4PP measurement device are detailed for the mechanical and electrical systems. Free and open source software and firmware are developed to operate the tool. The OS4PP was validated against a wide range of discrete resistors and indium tin oxide (ITO samples of different thicknesses both pre- and post-annealing. The OS4PP was then compared to two commercial proprietary systems. Results of resistors from 10 to 1 MΩ show errors of less than 1% for the OS4PP. The 3-D mapping of sheet resistance of ITO samples successfully demonstrated the automated capability to measure non-uniformities in large-area samples. The results indicate that all measured values are within the same order of magnitude when compared to two proprietary measurement systems. In conclusion, the OS4PP system, which costs less than 70% of manual proprietary systems, is comparable electrically while offering automated 100 micron positional accuracy for measuring sheet resistance over larger areas.

  6. Open-Source Automated Mapping Four-Point Probe.

    Science.gov (United States)

    Chandra, Handy; Allen, Spencer W; Oberloier, Shane W; Bihari, Nupur; Gwamuri, Jephias; Pearce, Joshua M

    2017-01-26

    Scientists have begun using self-replicating rapid prototyper (RepRap) 3-D printers to manufacture open source digital designs of scientific equipment. This approach is refined here to develop a novel instrument capable of performing automated large-area four-point probe measurements. The designs for conversion of a RepRap 3-D printer to a 2-D open source four-point probe (OS4PP) measurement device are detailed for the mechanical and electrical systems. Free and open source software and firmware are developed to operate the tool. The OS4PP was validated against a wide range of discrete resistors and indium tin oxide (ITO) samples of different thicknesses both pre- and post-annealing. The OS4PP was then compared to two commercial proprietary systems. Results of resistors from 10 to 1 MΩ show errors of less than 1% for the OS4PP. The 3-D mapping of sheet resistance of ITO samples successfully demonstrated the automated capability to measure non-uniformities in large-area samples. The results indicate that all measured values are within the same order of magnitude when compared to two proprietary measurement systems. In conclusion, the OS4PP system, which costs less than 70% of manual proprietary systems, is comparable electrically while offering automated 100 micron positional accuracy for measuring sheet resistance over larger areas.

  7. Preparation of very small point sources for high resolution radiography

    International Nuclear Information System (INIS)

    Case, F.N.

    1976-01-01

    The need for very small point sources of high specific activity 192 Ir, 169 Yb, 170 Tm, and 60 Co in non-destructive testing has motivated the development of techniques for the fabrication of these sources. To prepare 192 Ir point sources for use in examination of tube sheet welds in LMFBR heat exchangers, 191 Ir enriched to greater than 90 percent was melted in a helium blanketed arc to form spheres as small as 0.38 mm in diameter. Methods were developed to form the roughly spherical shaped arc product into nearly symmetrical spheres that could be used for high resolution radiography. Similar methods were used for spherical shaped sources of 169 Yb and 170 Tm. The oxides were arc melted to form rough spheres followed by grinding to precise dimensions, neutron irradiation of the spheres at a flux of 2 to 3 x 10 15 nv, and use of enriched 168 Yb to provide the maximum specific activity. Cobalt-60 with a specific activity of greater than 1100 Ci/g was prepared by processing 59 Co that had been neutron irradiated to nearly complete burnup of the 59 Co target to produce 60 Co, 61 Ni, and 62 Ni. Ion exchange methods were used to separate the cobalt from the nickel. The cobalt was reduced to metal by plating either onto aluminum foil which was dissolved away from the cobalt plate, or by plating onto mercury to prepare amalgam that could be easily formed into a pellet of cobalt with exclusion of the mercury. Both methods are discussed

  8. Rainfall Deduction Method for Estimating Non-Point Source Pollution Load for Watershed

    OpenAIRE

    Cai, Ming; Li, Huai-en; KAWAKAMI, Yoji

    2004-01-01

    The water pollution can be divided into point source pollution (PSP) and non-point source pollution (NSP). Since the point source pollution has been controlled, the non-point source pollution is becoming the main pollution source. The prediction of NSP load is being increasingly important in water pollution controlling and planning in watershed. Considering the monitoring data shortage of NPS in China, a practical estimation method of non-point source pollution load --- rainfall deduction met...

  9. Source term reduction at DAEC (including stellite ball recycling)

    International Nuclear Information System (INIS)

    Smith, R.; Schebler, D.

    1995-01-01

    The Duane Arnold Energy Center was seeking methods to reduce dose rates from the drywell due to Co-60. Duane Arnold is known in the industry to have one of the highest drywell dose rates from the industry standardized 'BRAC' point survey. A prime method to reduce dose rates due to Co-60 is the accelerated replacement of stellite pins and rollers in control rod blades due to their high stellite (cobalt) content. Usually the cobalt content in alloys of stellite is greater than 60% cobalt by weight. During the RFO-12 refueling outage at Duane Arnold, all of the remaining cobalt bearing control rod blades were replaced and new stellite free control rod blades were installed in the core. This left Duane Arnold with the disposal of highly radioactive stellite pins and rollers. The processing of control rod blades for disposal is a very difficult evolution. First, the velocity limiter (a bottom portion of the component) and the highly radioactive upper stellite control rod blade ins and rollers are separated from the control rod blade. Next, the remainder of the control rod blade is processed (chopped and/or crushed) to aid packaging the waste for disposal. The stellite bearings are then often carefully placed in with the rest of the waste in a burial liner to provide shielding for disposal or more often are left as 'orphans' in the spent fuel pool because their high specific activity create shipping and packaging problems. Further investigation by the utility showed that the stellite balls and pins could be recycled to a source manufacturer rather than disposed of in a low-level burial site. The cost savings to the utility was on the order of $200,000 with a gross savings of $400,000 in savings in burial site charges. A second advantage of the recycling of the stellite pins and rollers was a reduction in control in radioactive waste shipments

  10. The peak efficiency calibration of volume source using 152Eu point source in computer

    International Nuclear Information System (INIS)

    Shen Tingyun; Qian Jianfu; Nan Qinliang; Zhou Yanguo

    1997-01-01

    The author describes the method of the peak efficiency calibration of volume source by means of 152 Eu point source for HPGe γ spectrometer. The peak efficiency can be computed by Monte Carlo simulation, after inputting parameter of detector. The computation results are in agreement with the experimental results with an error of +-3.8%, with an exception one is about +-7.4%

  11. Atmospheric mercury dispersion modelling from two nearest hypothetical point sources

    Energy Technology Data Exchange (ETDEWEB)

    Al Razi, Khandakar Md Habib; Hiroshi, Moritomi; Shinji, Kambara [Environmental and Renewable Energy System (ERES), Graduate School of Engineering, Gifu University, Yanagido, Gifu City, 501-1193 (Japan)

    2012-07-01

    The Japan coastal areas are still environmentally friendly, though there are multiple air emission sources originating as a consequence of several developmental activities such as automobile industries, operation of thermal power plants, and mobile-source pollution. Mercury is known to be a potential air pollutant in the region apart from SOX, NOX, CO and Ozone. Mercury contamination in water bodies and other ecosystems due to deposition of atmospheric mercury is considered a serious environmental concern. Identification of sources contributing to the high atmospheric mercury levels will be useful for formulating pollution control and mitigation strategies in the region. In Japan, mercury and its compounds were categorized as hazardous air pollutants in 1996 and are on the list of 'Substances Requiring Priority Action' published by the Central Environmental Council of Japan. The Air Quality Management Division of the Environmental Bureau, Ministry of the Environment, Japan, selected the current annual mean environmental air quality standard for mercury and its compounds of 0.04 ?g/m3. Long-term exposure to mercury and its compounds can have a carcinogenic effect, inducing eg, Minamata disease. This study evaluates the impact of mercury emissions on air quality in the coastal area of Japan. Average yearly emission of mercury from an elevated point source in this area with background concentration and one-year meteorological data were used to predict the ground level concentration of mercury. To estimate the concentration of mercury and its compounds in air of the local area, two different simulation models have been used. The first is the National Institute of Advanced Science and Technology Atmospheric Dispersion Model for Exposure and Risk Assessment (AIST-ADMER) that estimates regional atmospheric concentration and distribution. The second is the Hybrid Single Particle Lagrangian Integrated trajectory Model (HYSPLIT) that estimates the atmospheric

  12. Discretized energy minimization in a wave guide with point sources

    Science.gov (United States)

    Propst, G.

    1994-01-01

    An anti-noise problem on a finite time interval is solved by minimization of a quadratic functional on the Hilbert space of square integrable controls. To this end, the one-dimensional wave equation with point sources and pointwise reflecting boundary conditions is decomposed into a system for the two propagating components of waves. Wellposedness of this system is proved for a class of data that includes piecewise linear initial conditions and piecewise constant forcing functions. It is shown that for such data the optimal piecewise constant control is the solution of a sparse linear system. Methods for its computational treatment are presented as well as examples of their applicability. The convergence of discrete approximations to the general optimization problem is demonstrated by finite element methods.

  13. Super-resolution for a point source using positive refraction

    Science.gov (United States)

    Miñano, Juan C.; Benítez, Pablo; González, Juan C.; Grabovičkić, Dejan; Ahmadpanahi, Hamed

    Leonhardt demonstrated (2009) that the 2D Maxwell Fish Eye lens (MFE) can focus perfectly 2D Helmholtz waves of arbitrary frequency, i.e., it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a receptor called "perfect drain" (PD) located at the corresponding MFE image point. The PD has the property of absorbing the complete radiation without radiation or scattering and it has been claimed as necessary to obtain super-resolution (SR) in the MFE. However, a prototype using a "drain" different from the PD has shown λ/5 resolution for microwave frequencies (Ma et al, 2010). Recently, the SR properties of a device equivalent to the MFE, called the Spherical Geodesic Waveguide (SGW) (Miñano et al, 2012) have been analyzed. The reported results show resolution up to λ /3000, for the SGW loaded with the perfect drain, and up to λ /500 for the SGW without perfect drain. The perfect drain was realized as a coaxial probe loaded with properly calculated impedance. The SGW provides SR only in a narrow band of frequencies close to the resonance Schumann frequencies. Here we analyze the SGW loaded with a small "perfect drain region" (González et al, 2011). This drain is designed as a region made of a material with complex permittivity. The comparative results show that there is no significant difference in the SR properties for both perfect drain designs.

  14. Trans-Z-source and Γ-Z-source neutral-point-clamped inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Loh, Poh Chiang; Blaabjerg, Frede

    2015-01-01

    Z-source neutral-point-clamped (NPC) inverters are earlier proposed for obtaining voltage buck-boost and three-level switching simultaneously. Their performances are, however, constrained by a trade-off between their input-to-output gain and modulation ratio. This trade-off can lead to high...

  15. Power-Law Template for IR Point Source Clustering

    Science.gov (United States)

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

    2011-01-01

    We perform a combined fit to angular power spectra of unresolved infrared (IR) point sources from the Planck satellite (at 217,353,545 and 857 GHz, over angular scales 100 clustered power over the range of angular scales and frequencies considered is well fit by a simple power law of the form C_l\\propto I(sup -n) with n = 1.25 +/- 0.06. While the IR sources are understood to lie at a range of redshifts, with a variety of dust properties, we find that the frequency dependence of the clustering power can be described by the square of a modified blackbody, nu(sup beta) B(nu,T_eff), with a single emissivity index beta = 2.20 +/- 0.07 and effective temperature T_eff= 9.7 K. Our predictions for the clustering amplitude are consistent with existing ACT and South Pole Telescope results at around 150 and 220 GHz, as is our prediction for the effective dust spectral index, which we find to be alpha_150-220 = 3.68 +/- 0.07 between 150 and 220 GHz. Our constraints on the clustering shape and frequency dependence can be used to model the IR clustering as a contaminant in Cosmic Microwave Background anisotropy measurements. The combined Planck and BLAST data also rule out a linear bias clustering model.

  16. Power-Law Template for Infrared Point-Source Clustering

    Science.gov (United States)

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

    2012-01-01

    We perform a combined fit to angular power spectra of unresolved infrared (IR) point sources from the Planck satellite (at 217, 353, 545, and 857 GHz, over angular scales 100 approx clustered power over the range of angular scales and frequencies considered is well fitted by a simple power law of the form C(sup clust)(sub l) varies as l (sub -n) with n = 1.25 +/- 0.06. While the IR sources are understood to lie at a range of redshifts, with a variety of dust properties, we find that the frequency dependence of the clustering power can be described by the square of a modified blackbody, ?(sup Beta)B(?, T(sub eff) ), with a single emissivity index Beta = 2.20 +/- 0.07 and effective temperature T(sub eff) = 9.7 K. Our predictions for the clustering amplitude are consistent with existing ACT and South Pole Telescope results at around 150 and 220 GHz, as is our prediction for the effective dust spectral index, which we find to be alpha(sub 150-220) = 3.68 +/- 0.07 between 150 and 220 GHz. Our constraints on the clustering shape and frequency dependence can be used to model the IR clustering as a contaminant in cosmic microwave background anisotropy measurements. The combined Planck and BLAST data also rule out a linear bias clustering model.

  17. Landscape planning for agricultural nonpoint source pollution reduction III: Assessing phosphorus and sediment reduction potential

    Science.gov (United States)

    Diebel, M.W.; Maxted, J.T.; Robertson, Dale M.; Han, S.; Vander Zanden, M. J.

    2009-01-01

    Riparian buffers have the potential to improve stream water quality in agricultural landscapes. This potential may vary in response to landscape characteristics such as soils, topography, land use, and human activities, including legacies of historical land management. We built a predictive model to estimate the sediment and phosphorus load reduction that should be achievable following the implementation of riparian buffers; then we estimated load reduction potential for a set of 1598 watersheds (average 54 km2) in Wisconsin. Our results indicate that land cover is generally the most important driver of constituent loads in Wisconsin streams, but its influence varies among pollutants and according to the scale at which it is measured. Physiographic (drainage density) variation also influenced sediment and phosphorus loads. The effect of historical land use on present-day channel erosion and variation in soil texture are the most important sources of phosphorus and sediment that riparian buffers cannot attenuate. However, in most watersheds, a large proportion (approximately 70%) of these pollutants can be eliminated from streams with buffers. Cumulative frequency distributions of load reduction potential indicate that targeting pollution reduction in the highest 10% of Wisconsin watersheds would reduce total phosphorus and sediment loads in the entire state by approximately 20%. These results support our approach of geographically targeting nonpoint source pollution reduction at multiple scales, including the watershed scale. ?? 2008 Springer Science+Business Media, LLC.

  18. POWER-LAW TEMPLATE FOR INFRARED POINT-SOURCE CLUSTERING

    Energy Technology Data Exchange (ETDEWEB)

    Addison, Graeme E.; Dunkley, Joanna [Sub-department of Astrophysics, University of Oxford, Denys Wilkinson Building, Keble Road, Oxford OX1 3RH (United Kingdom); Hajian, Amir; Das, Sudeep; Hincks, Adam D.; Page, Lyman A.; Staggs, Suzanne T. [Joseph Henry Laboratories of Physics, Jadwin Hall, Princeton University, Princeton, NJ 08544 (United States); Viero, Marco [Department of Astronomy, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Bond, J. Richard [Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, ON M5S 3H8 (Canada); Devlin, Mark J.; Reese, Erik D. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd Street, Philadelphia, PA 19104 (United States); Halpern, Mark; Scott, Douglas [Department of Physics and Astronomy, University of British Columbia, Vancouver, BC V6T 1Z4 (Canada); Hlozek, Renee; Marriage, Tobias A.; Spergel, David N. [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States); Moodley, Kavilan [Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, University of KwaZulu-Natal, Durban 4041 (South Africa); Wollack, Edward [NASA/Goddard Space Flight Center, Code 665, Greenbelt, MD 20771 (United States)

    2012-06-20

    We perform a combined fit to angular power spectra of unresolved infrared (IR) point sources from the Planck satellite (at 217, 353, 545, and 857 GHz, over angular scales 100 {approx}< l {approx}< 2200), the Balloon-borne Large-Aperture Submillimeter Telescope (BLAST; 250, 350, and 500 {mu}m; 1000 {approx}< l {approx}< 9000), and from correlating BLAST and Atacama Cosmology Telescope (ACT; 148 and 218 GHz) maps. We find that the clustered power over the range of angular scales and frequencies considered is well fitted by a simple power law of the form C{sup clust}{sub l}{proportional_to}l{sup -n} with n = 1.25 {+-} 0.06. While the IR sources are understood to lie at a range of redshifts, with a variety of dust properties, we find that the frequency dependence of the clustering power can be described by the square of a modified blackbody, {nu}{sup {beta}} B({nu}, T{sub eff}), with a single emissivity index {beta} = 2.20 {+-} 0.07 and effective temperature T{sub eff} = 9.7 K. Our predictions for the clustering amplitude are consistent with existing ACT and South Pole Telescope results at around 150 and 220 GHz, as is our prediction for the effective dust spectral index, which we find to be {alpha}{sub 150-220} = 3.68 {+-} 0.07 between 150 and 220 GHz. Our constraints on the clustering shape and frequency dependence can be used to model the IR clustering as a contaminant in cosmic microwave background anisotropy measurements. The combined Planck and BLAST data also rule out a linear bias clustering model.

  19. Low energy electron point source microscopy: beyond imaging

    Energy Technology Data Exchange (ETDEWEB)

    Beyer, Andre; Goelzhaeuser, Armin [Physics of Supramolecular Systems and Surfaces, University of Bielefeld, Postfach 100131, 33501 Bielefeld (Germany)

    2010-09-01

    Low energy electron point source (LEEPS) microscopy has the capability to record in-line holograms at very high magnifications with a fairly simple set-up. After the holograms are numerically reconstructed, structural features with the size of about 2 nm can be resolved. The achievement of an even higher resolution has been predicted. However, a number of obstacles are known to impede the realization of this goal, for example the presence of electric fields around the imaged object, electrostatic charging or radiation induced processes. This topical review gives an overview of the achievements as well as the difficulties in the efforts to shift the resolution limit of LEEPS microscopy towards the atomic level. A special emphasis is laid on the high sensitivity of low energy electrons to electrical fields, which limits the structural determination of the imaged objects. On the other hand, the investigation of the electrical field around objects of known structure is very useful for other tasks and LEEPS microscopy can be extended beyond the task of imaging. The determination of the electrical resistance of individual nanowires can be achieved by a proper analysis of the corresponding LEEPS micrographs. This conductivity imaging may be a very useful application for LEEPS microscopes. (topical review)

  20. BEAMLINE-CONTROLLED STEERING OF SOURCE-POINT ANGLE AT THE ADVANCED PHOTON SOURCE

    Energy Technology Data Exchange (ETDEWEB)

    Emery, L.; Fystro, G.; Shang, H.; Smith, M.

    2017-06-25

    An EPICS-based steering software system has been implemented for beamline personnel to directly steer the angle of the synchrotron radiation sources at the Advanced Photon Source. A script running on a workstation monitors "start steering" beamline EPICS records, and effects a steering given by the value of the "angle request" EPICS record. The new system makes the steering process much faster than before, although the older steering protocols can still be used. The robustness features of the original steering remain. Feedback messages are provided to the beamlines and the accelerator operators. Underpinning this new steering protocol is the recent refinement of the global orbit feedback process whereby feedforward of dipole corrector set points and orbit set points are used to create a local steering bump in a rapid and seamless way.

  1. Nutrient Losses from Non-Point Sources or from Unidentified Point Sources? Application Examples of the Smartphone Based Nitrate App.

    Science.gov (United States)

    Rozemeijer, J.; Ekkelenkamp, R.; van der Zaan, B.

    2017-12-01

    In 2016 Deltares launched the free to use Nitrate App which accurately reads and interprets nitrate test strips. The app directly displays the measured concentration and gives the option to share the result. Shared results are visualised in map functionality within the app and online. Since its introduction we've been seeing an increasing number of nitrate app applications. In this presentation we show some unanticipated types of application. The Nitrate App was originally intended to enable farmers to measure nitrate concentrations on their own farms. This may encourage farmers to talk to specialists about the right nutrient best management practices (BMP's) for their farm. Several groups of farmers have recently started to apply the Nitrate App and to discuss their results with each other and with the authorities. Nitrate concentration routings in catchments have proven to be another useful application. Within a day a person can generate a catchment scale nitrate concentration map identifying nitrate loss hotspots. In several routings in agricultural catchments clear point sources were found, for example at small scale manure processing plants. These routings proved that the Nitrate App can help water managers to target conservation practices more accurately to areas with the highest nitrate concentrations and loads. Other current applications are the screening of domestic water wells in California, the collection of extra measurements (also pH and NH4) in the National Monitoring Network for the Evaluation of the Manure Policy in the Netherlands, and several educational initiatives in cooperation with schools and universities.

  2. An Improved Statistical Point-source Foreground Model for the Epoch of Reionization

    Energy Technology Data Exchange (ETDEWEB)

    Murray, S. G.; Trott, C. M.; Jordan, C. H. [ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) (Australia)

    2017-08-10

    We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions for the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.

  3. An Improved Statistical Point-source Foreground Model for the Epoch of Reionization

    Science.gov (United States)

    Murray, S. G.; Trott, C. M.; Jordan, C. H.

    2017-08-01

    We present a sophisticated statistical point-source foreground model for low-frequency radio Epoch of Reionization (EoR) experiments using the 21 cm neutral hydrogen emission line. Motivated by our understanding of the low-frequency radio sky, we enhance the realism of two model components compared with existing models: the source count distributions as a function of flux density and spatial position (source clustering), extending current formalisms for the foreground covariance of 2D power-spectral modes in 21 cm EoR experiments. The former we generalize to an arbitrarily broken power law, and the latter to an arbitrary isotropically correlated field. This paper presents expressions for the modified covariance under these extensions, and shows that for a more realistic source spatial distribution, extra covariance arises in the EoR window that was previously unaccounted for. Failure to include this contribution can yield bias in the final power-spectrum and under-estimate uncertainties, potentially leading to a false detection of signal. The extent of this effect is uncertain, owing to ignorance of physical model parameters, but we show that it is dependent on the relative abundance of faint sources, to the effect that our extension will become more important for future deep surveys. Finally, we show that under some parameter choices, ignoring source clustering can lead to false detections on large scales, due to both the induced bias and an artificial reduction in the estimated measurement uncertainty.

  4. Modeling the effects of integrating larval habitat source reduction and insecticide treated nets for malaria control.

    Directory of Open Access Journals (Sweden)

    Laith Yakob

    Full Text Available Integrated vector management for malaria control has received a lot of recent interest. Attacking multiple points in the transmission cycle is hoped to act synergistically and improve upon current single-tool interventions based on the use of insecticide-treated bed nets (ITNs. In the present study, we theoretically examined the application of larval habitat source reduction with ITNs in reducing malaria transmission. We selected this type of environmental management to complement ITNs because of a potential secondary mode of action that both control strategies share. In addition to increasing vector mortality, ITNs reduce the rate at which female mosquitoes locate human hosts for blood feeding, thereby extending their gonotrophic cycle. Similarly, while reducing adult vector emergence and abundance, source reduction of larval habitats may prolong the cycle duration by extending delays in locating oviposition sites. We found, however, that source reduction of larval habitats only operates through this secondary mode of action when habitat density is below a critical threshold. Hence, we illustrate how this strategy becomes increasingly effective when larval habitats are limited. We also demonstrate that habitat source reduction is better suited to human populations of higher density and in the presence of insecticide resistance or when the insecticidal properties of ITNs are depleted.

  5. Impact of point source pollution on groundwater quality

    International Nuclear Information System (INIS)

    Gill, M.A.; Solehria, B.A.; Rai, N.I.

    2005-01-01

    The management of point source pollution (municipal and industrial waste water) is an important item on Brown Agenda confronting urban planners and policy makers. The industrial concerns and households produce enormous amount of waste water, which has to be disposed of through the municipal sewage system. Generally, municipal wastewater management is done on non-scientific lines, resulting in considerable social and economic loss and gradual degradation of the natural resources. The present study highlights that how the poor management practices, lack of infrastructure, and poor disposal system-comprising of mostly open, un-walled or partially lined drains, affect the groundwater quality and render it unfit for human consumption. Satiana Road sludge carrier at Faisalabad city, receiving effluents of about 67 textile units, 4 oil mills, 2 ice factories, 3 laundris and domestic waste water of Peoples Colony No.1, Maqbool Road and Ghulam Rasool Nagar was selected to derive quantitative and qualitative estimates of TDS, Na, Cl and heavy metals namely Fe, Cu and Pb of the waste water and their leaching around the sludge carrier. The measurement of leaching of TDS, Na/sup +/, and Cl/sup -1/ per 1000 m basis in lined section was 818, 550 and 228 tons, respectively. Where as in the unlined section, annual increase of TDS, Na/sup /+, and Cl/sup -/ was 2404,1615 and 669 tons per 1000 m respectively. In case of leaching of metals through the sludge carrier, Cu was at the top with 8.4 tons per annum per 1000 m followed by Fe and Pb with 6.66 and 1.2 tons per annum per 1000 m respectively. The concentration of all the salts/metals studied were higher in groundwater near the sludge carrier which decreased with increase in distance. The groundwater contamination in unlined portions is greater than lined portions, which might be due to higher seepage losses in unlined portions of the sludge carrier (4.9 % per 1000 m) as compared to relatively low seepage losses in lined portion of

  6. Reductive dechlorination of trichloroethene DNAPL source zones: source zone architecture versus electron donor availability

    Science.gov (United States)

    Krol, M.; Kokkinaki, A.; Sleep, B.

    2014-12-01

    The persistence of dense-non-aqueous-phase liquids (DNAPLs) in the subsurface has led practitioners and regulatory agencies to turn towards low-maintenance, low-cost remediation methods. Biological degradation has been suggested as a possible solution, based on the well-proven ability of certain microbial species to break down dissolved chlorinated ethenes under favorable conditions. However, the biodegradation of pure phase chlorinated ethenes is subject to additional constraints: the continuous release of electron acceptor at a rate governed by mass transfer kinetics, and the temporal and spatial heterogeneity of DNAPL source zones which leads to spatially and temporally variable availability of the reactants for reductive dechlorination. In this work, we investigate the relationship between various DNAPL source zone characteristics and reaction kinetics using COMPSIM, a multiphase groundwater model that considers non-equilibrium mass transfer and Monod-type kinetics for reductive dechlorination. Numerical simulations are performed for simple, homogeneous trichloroethene DNAPL source zones to demonstrate the effect of single source zone characteristics, as well as for larger, more realistic heterogeneous source zones. It is shown that source zone size, and mass transfer kinetics may have a decisive effect on the predicted bio-enhancement. Finally, we evaluate the performance of DNAPL bioremediation for realistic, thermodynamically constrained, concentrations of electron donor. Our results indicate that the latter may be the most important limitation for the success of DNAPL bioremediation, leading to reduced bio-enhancement and, in many cases, comparable performance with water flooding.

  7. Determination of disintegration rates of a 60Co point source and volume sources by the sum-peak method

    International Nuclear Information System (INIS)

    Kawano, Takao; Ebihara, Hiroshi

    1990-01-01

    The disintegration rates of 60 Co as a point source (<2 mm in diameter on a thin plastic disc) and volume sources (10-100 mL solutions in a polyethylene bottle) are determined by the sum-peak method. The sum-peak formula gives the exact disintegration rate for the point source at different positions from the detector. However, increasing the volume of the solution results in enlarged deviations from the true disintegration rate. Extended sources must be treated as an amalgam of many point sources. (author)

  8. A solution for tensor reduction of one-loop N-point functions with N{>=}6

    Energy Technology Data Exchange (ETDEWEB)

    Fleischer, J. [Bielefeld Univ. (Germany). Fakultaet fuer Physik; Riemann, T. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2011-11-15

    Collisions at the LHC produce many-particle final states, and for precise predictions the one-loop N-point corrections are needed. We study here the tensor reduction for Feynman integrals with N{>=}6. A general, recursive solution by Binoth et al. expresses N-point Feynman integrals of rank R in terms of (N-1)-point Feynman integrals of rank (R-1) (for N{>=}6). We show that the coefficients can be obtained analytically from suitable representations of the metric tensor. Contractions of the tensor integrals with external momenta can be efficiently expressed as well. We consider our approach particularly well suited for automatization. (orig.)

  9. Characteristics of infrared point sources associated with OH masers

    International Nuclear Information System (INIS)

    Mu Jimang; Esimbek, Jarken; Zhou Jianjun; Zhang Haijuan

    2010-01-01

    We collect 3249 OH maser sources from the literature published up to April 2007, and compile a new catalog of OH masers. We look for the exciting sources of these masers and their infrared properties from IRAS and MSX data, and make a statistical study. MSX sources associated with stellar 1612 MHz OH masers are located mainly above the blackbody line; this is caused by the dust absorption of stellar envelopes, especially in the MSX A band. The mid-IR sources associated with stellar OH masers are concentrated in a small region in an [A]-[D] vs. [A]-[E] diagram with a small fraction of contamination; this gives us a new criterion to search for new stellar OH masers and distinguish stellar masers from unknown types of OH masers. IR sources associated with 1612 MHz stellar OH masers show an expected result: the average flux of sources with F60 > F25 increases with increasing wavelength, while those with F60 F25.

  10. Analysis of point source size on measurement accuracy of lateral point-spread function of confocal Raman microscopy

    Science.gov (United States)

    Fu, Shihang; Zhang, Li; Hu, Yao; Ding, Xiang

    2018-01-01

    Confocal Raman Microscopy (CRM) has matured to become one of the most powerful instruments in analytical science because of its molecular sensitivity and high spatial resolution. Compared with conventional Raman Microscopy, CRM can perform three dimensions mapping of tiny samples and has the advantage of high spatial resolution thanking to the unique pinhole. With the wide application of the instrument, there is a growing requirement for the evaluation of the imaging performance of the system. Point-spread function (PSF) is an important approach to the evaluation of imaging capability of an optical instrument. Among a variety of measurement methods of PSF, the point source method has been widely used because it is easy to operate and the measurement results are approximate to the true PSF. In the point source method, the point source size has a significant impact on the final measurement accuracy. In this paper, the influence of the point source sizes on the measurement accuracy of PSF is analyzed and verified experimentally. A theoretical model of the lateral PSF for CRM is established and the effect of point source size on full-width at half maximum of lateral PSF is simulated. For long-term preservation and measurement convenience, PSF measurement phantom using polydimethylsiloxane resin, doped with different sizes of polystyrene microspheres is designed. The PSF of CRM with different sizes of microspheres are measured and the results are compared with the simulation results. The results provide a guide for measuring the PSF of the CRM.

  11. Tapping the zero-point energy as an energy source

    International Nuclear Information System (INIS)

    King, M.B.

    1991-01-01

    This paper reports that the hypothesis for tapping the zero-point energy (ZPE) arises by combining the theories of the ZPE with the theories of system self-organization. The vacuum polarization of atomic nuclei might allow their synchronous motion to activate a ZPE coherence. Experimentally observed plasma ion-acoustic anomalies as well as inventions utilizing cycloid ion motions may offer supporting evidence. The suggested experiment of rapidly circulating a charged plasma in a vortex ring might induce a sufficient zero-point energy interaction to manifest a gravitational anomaly. An invention utilizing abrupt E field rotation to create virtual charge exhibits excessive energy output

  12. Characterization of non point source pollutants and their dispersion ...

    African Journals Online (AJOL)

    EJIRO

    landing site in Uganda. N. Banadda. Agricultural and Bio-Systems Engineering Department, Makerere University, P. O. Box 7062, Kampala, Uganda. E-mail: banadda@agric.mak.ac.ug. Fax: +256-414-53.16.41. Accepted 5 January, 2011. The aim of this research is to characterize non point pollutants and their dispersion in ...

  13. Family of Quantum Sources for Improving Near Field Accuracy in Transducer Modeling by the Distributed Point Source Method

    Directory of Open Access Journals (Sweden)

    Dominique Placko

    2016-10-01

    Full Text Available The distributed point source method, or DPSM, developed in the last decade has been used for solving various engineering problems—such as elastic and electromagnetic wave propagation, electrostatic, and fluid flow problems. Based on a semi-analytical formulation, the DPSM solution is generally built by superimposing the point source solutions or Green’s functions. However, the DPSM solution can be also obtained by superimposing elemental solutions of volume sources having some source density called the equivalent source density (ESD. In earlier works mostly point sources were used. In this paper the DPSM formulation is modified to introduce a new kind of ESD, replacing the classical single point source by a family of point sources that are referred to as quantum sources. The proposed formulation with these quantum sources do not change the dimension of the global matrix to be inverted to solve the problem when compared with the classical point source-based DPSM formulation. To assess the performance of this new formulation, the ultrasonic field generated by a circular planer transducer was compared with the classical DPSM formulation and analytical solution. The results show a significant improvement in the near field computation.

  14. Nomogram for Determining Shield Thickness for Point and Line Sources of Gamma Rays

    International Nuclear Information System (INIS)

    Joenemalm, C.; Malen, K

    1966-10-01

    A set of nomograms is given for the determination of the required shield thickness against gamma radiation. The sources handled are point and infinite line sources with shields of Pb, Fe, magnetite concrete (p = 3.6), ordinary concrete (p = 2.3) or water. The gamma energy range covered is 0.5 - 10 MeV. The nomograms are directly applicable for source and dose points on the surfaces of the shield. They can easily be extended to source and dose points in other positions by applying a geometrical correction. Also included are data for calculation of the source strength for the most common materials and for fission product sources

  15. Nomogram for Determining Shield Thickness for Point and Line Sources of Gamma Rays

    Energy Technology Data Exchange (ETDEWEB)

    Joenemalm, C; Malen, K

    1966-10-15

    A set of nomograms is given for the determination of the required shield thickness against gamma radiation. The sources handled are point and infinite line sources with shields of Pb, Fe, magnetite concrete (p = 3.6), ordinary concrete (p = 2.3) or water. The gamma energy range covered is 0.5 - 10 MeV. The nomograms are directly applicable for source and dose points on the surfaces of the shield. They can easily be extended to source and dose points in other positions by applying a geometrical correction. Also included are data for calculation of the source strength for the most common materials and for fission product sources.

  16. Effect of Ice Massage on Hoku Point for Reduction of Labor Pain

    Directory of Open Access Journals (Sweden)

    N Naghshin

    2008-01-01

    Full Text Available Introduction: One the most anxious moments for mothers and families is labor pain and various methods for its relief have an effect on labor management, patient satisfaction and labor outcome. Both pharmacological and non-pharmacological methods are used to relieve labor pain, but in recently years, researchers have focused their attention to non-pharmacological methods for reduction of labor pain. Acupressure is one of the pain relieving methods that can be used for labor pain, but there have been few studies to date. The purpose of this research was to determine the effect of Hoku point ice massage on labor pain. Methods: Participants of this clinical trial study were 60 pregnant women having the inclusive criteria. Participants were randomly divided to two groups of thirty, each. (Control Group=only touch of Hoku point, Case group= ice massage of Huko point. This procedure was done for thirty minutes. Labor pain of subjects was measured by visual analog scale before and after the procedure. Results: There was no statistical difference between the gestational age, parity and age of the two groups. Results showed that reduction of labor pain by ice massage of Huko point was statistically significant (P<0.001. Conclusion: Acupressure is a noninvasive, simple and cheap method of relieving pain and our study confirms its effect on reduction of labor pain. This method is therefore applicable in delivery rooms.

  17. Tokamak startup using point-source dc helicity injection.

    Science.gov (United States)

    Battaglia, D J; Bongard, M W; Fonck, R J; Redd, A J; Sontag, A C

    2009-06-05

    Startup of a 0.1 MA tokamak plasma is demonstrated on the ultralow aspect ratio Pegasus Toroidal Experiment using three localized, high-current density sources mounted near the outboard midplane. The injected open field current relaxes via helicity-conserving magnetic turbulence into a tokamaklike magnetic topology where the maximum sustained plasma current is determined by helicity balance and the requirements for magnetic relaxation.

  18. Reduction formalism for dimensionally regulated one-loop N-point integrals

    International Nuclear Information System (INIS)

    Binoth, T.; Guillet, J.Ph.; Heinrich, G.

    2000-01-01

    We consider one-loop scalar and tensor integrals with an arbitrary number of external legs relevant for multi-parton processes in massless theories. We present a procedure to reduce N-point scalar functions with generic 4-dimensional external momenta to box integrals in (4-2ε) dimensions. We derive a formula valid for arbitrary N and give an explicit expression for N=6. Further a tensor reduction method for N-point tensor integrals is presented. We prove that generically higher dimensional integrals contribute only to order ε for N≥5. The tensor reduction can be solved iteratively such that any tensor integral is expressible in terms of scalar integrals. Explicit formulas are given up to N=6

  19. [A landscape ecological approach for urban non-point source pollution control].

    Science.gov (United States)

    Guo, Qinghai; Ma, Keming; Zhao, Jingzhu; Yang, Liu; Yin, Chengqing

    2005-05-01

    Urban non-point source pollution is a new problem appeared with the speeding development of urbanization. The particularity of urban land use and the increase of impervious surface area make urban non-point source pollution differ from agricultural non-point source pollution, and more difficult to control. Best Management Practices (BMPs) are the effective practices commonly applied in controlling urban non-point source pollution, mainly adopting local repairing practices to control the pollutants in surface runoff. Because of the close relationship between urban land use patterns and non-point source pollution, it would be rational to combine the landscape ecological planning with local BMPs to control the urban non-point source pollution, which needs, firstly, analyzing and evaluating the influence of landscape structure on water-bodies, pollution sources and pollutant removal processes to define the relationships between landscape spatial pattern and non-point source pollution and to decide the key polluted fields, and secondly, adjusting inherent landscape structures or/and joining new landscape factors to form new landscape pattern, and combining landscape planning and management through applying BMPs into planning to improve urban landscape heterogeneity and to control urban non-point source pollution.

  20. Calculation of dose for β point and sphere sources in soft tissue

    International Nuclear Information System (INIS)

    Sun Fuyin; Yuan Shuyu; Tan Jian

    1999-01-01

    Objective: To compare the results of the distribution of dose rate calculated by three typical methods for point source and sphere source of β nuclide. Methods: Calculating and comparing the distributions of dose rate from 32 P β point and sphere sources in soft tissue calculated by the three methods published in references, [1]. [2] and [3], respectively. Results: For the point source of 3.7 x 10 7 Bq (1mCi), the variations of the calculation results of the three formulas are within 10% if r≤0.35 g/cm 2 , r being the distance from source, and larger than 10% if r > 0.35 g/cm 2 . For the sphere source whose volume is 50 μl and activity is 3.7 x 10 7 Bq(1 mCi), the variations are within 10% if z≤0.15 g/cm 2 , z being the distance from the surface of the sphere source to a point outside the sphere. Conclusion: The agreement of the distributions of the dose rate calculated by the three methods mentioned above for point and sphere β source are good if the distances from point source or the surface of sphere source to the points observed are small, and poor if they are large

  1. Agroforestry buffers for nonpoint source pollution reductions from agricultural watersheds.

    Science.gov (United States)

    Udawatta, Ranjith P; Garrett, Harold E; Kallenbach, Robert

    2011-01-01

    Despite increased attention and demand for the adoption of agroforestry practices throughout the world, rigorous long-term scientific studies confirming environmental benefits from the use of agroforestry practices are limited. The objective was to examine nonpoint-source pollution (NPSP) reduction as influenced by agroforestry buffers in watersheds under grazing and row crop management. The grazing study consists of six watersheds in the Central Mississippi Valley wooded slopes and the row crop study site consists of three watersheds in a paired watershed design in Central Claypan areas. Runoff water samples were analyzed for sediment, total nitrogen (TN), and total phosphorus (TP) for the 2004 to 2008 period. Results indicate that agroforestry and grass buffers on grazed and row crop management sites significantly reduce runoff, sediment, TN, and TP losses to streams. Buffers in association with grazing and row crop management reduced runoff by 49 and 19%, respectively, during the study period as compared with respective control treatments. Average sediment loss for grazing and row crop management systems was 13.8 and 17.9 kg ha yr, respectively. On average, grass and agroforestry buffers reduced sediment, TN, and TP losses by 32, 42, and 46% compared with the control treatments. Buffers were more effective in the grazing management practice than row crop management practice. These differences could in part be attributed to the differences in soils, management, and landscape features. Results from this study strongly indicate that agroforestry and grass buffers can be designed to improve water quality while minimizing the amount of land taken out of production. American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.

  2. Simultaneous Determination of Source Wavelet and Velocity Profile Using Impulsive Point-Source Reflections from a Layered Fluid

    National Research Council Canada - National Science Library

    Bube, K; Lailly, P; Sacks, P; Santosa, F; Symes, W. W

    1987-01-01

    .... We show that a quasi-impulsive, isotropic point source may be recovered simultaneously with the velocity profile from reflection data over a layered fluid, in linear (perturbation) approximation...

  3. Manifestation of external size reduction effects on the yield point of nanocrystalline rhodium using nanopillars approach

    International Nuclear Information System (INIS)

    Alshehri, Omar; Yavuz, Mustafa; Tsui Ting

    2013-01-01

    In this study, pure rhodium was fabricated and mechanically investigated at the nanoscale for the first time. The nanopillars approach was employed to study the effects of size on the yield point. Nanopillars with different diameters were fabricated using electroplating followed by uniaxial compression tests. Scanning electron microscopy (SEM) was used as a quality control technique by imaging the pillars before and after compression to ensure the absence of cracks, buckling, barrelling or any other problems. Transmission electron microscopy and SEM were used as microstructural characterization techniques. Due to substrate-induced effects, only the plastic region of the stress–strain curves were investigated, and it was revealed that the yield point increases with size reduction up to certain limit, then decreases with further reduction of the nanopillar size (diameter). The later weakening effect is consistent with the literature, which demonstrates the reversed size effect (the failure of the plasticity theory) in nanocrystalline metals, i.e. smaller is weaker. In this study, however, the effect of size reduction is not only weakening, but is strengthening-then-weakening, which the authors believe is the true behavior of nanocrystalline materials.

  4. Point source search techniques in ultra high energy gamma ray astronomy

    International Nuclear Information System (INIS)

    Alexandreas, D.E.; Biller, S.; Dion, G.M.; Lu, X.Q.; Yodh, G.B.; Berley, D.; Goodman, J.A.; Haines, T.J.; Hoffman, C.M.; Horch, E.; Sinnis, C.; Zhang, W.

    1993-01-01

    Searches for point astrophysical sources of ultra high energy (UHE) gamma rays are plagued by large numbers of background events from isotropic cosmic rays. Some of the methods that have been used to estimate the expected number of background events coming from the direction of a possible source are found to contain biases. Search techniques that avoid this problem are described. There is also a discussion of how to optimize the sensitivity of a search to emission from a point source. (orig.)

  5. Optical identifications of IRAS point sources: the Fornax, Hydra I and Coma clusters

    International Nuclear Information System (INIS)

    Wang, G.; Leggett, S.K.; Savage, A.

    1991-01-01

    We present optical identifications for 66 IRAS point sources in the region of the Fornax cluster of galaxies, 106 IRAS point sources in the region of the Hydra I cluster of galaxies (Abell 1060) and 59 IRAS point sources in the region of the Coma cluster of galaxies (Abell 1656). Eight other sources in Hydra I do not have optical counterparts and are very probably due to infrared cirrus. Twenty-three (35 per cent) of the Fornax sources are associated with stars and 43 (65 per cent) with galaxies; 48 (42 per cent) of the Hydra I sources are associated with stars and 58 (51 per cent) with galaxies; 18 (31 per cent) of the Coma sources are associated with stars and 41 (69 per cent) with galaxies. The stellar and infrared cirrus surface density is consistent with the galactic latitude of each field. (author)

  6. 75 FR 10438 - Effluent Limitations Guidelines and Standards for the Construction and Development Point Source...

    Science.gov (United States)

    2010-03-08

    ... Effluent Limitations Guidelines and Standards for the Construction and Development Point Source Category... technology-based Effluent Limitations Guidelines and New Source Performance Standards for the Construction... technology-based Effluent Limitations Guidelines and New Source Performance Standards for the Construction...

  7. Radio identifications of IRAS point sources with b greater than 30 deg

    International Nuclear Information System (INIS)

    Condon, J.J.; Broderick, J.J.; Virginia Polytechnic Institute and State Univ., Blacksburg)

    1986-01-01

    The present radio identifications of IRAS point sources on the basis of Green Bank 1400 MHz survey maps notes that 365 hot IR sources are not detectable radio sources, and that nearly all cool high latitude IRAS sources are extragalactic. The fainter IR-source identifications encompass optically bright quasars, BL Lac objects, Seyfert galaxies, and elliptical galaxies. No IRAS sources could be identified with distant elliptical radio galaxies, so that although the radio and IR fluxes of most IRAS extragalactic sources are tightly correlated, complete samples of strong radio and IR sources are almost completely disjoint; no more than 1 percent of the IR sources are radio sources and less than 1 percent of the radio sources are IR ones. 35 references

  8. LOWERING ICECUBE'S ENERGY THRESHOLD FOR POINT SOURCE SEARCHES IN THE SOUTHERN SKY

    Energy Technology Data Exchange (ETDEWEB)

    Aartsen, M. G. [Department of Physics, University of Adelaide, Adelaide, 5005 (Australia); Abraham, K. [Physik-department, Technische Universität München, D-85748 Garching (Germany); Ackermann, M. [DESY, D-15735 Zeuthen (Germany); Adams, J. [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch (New Zealand); Aguilar, J. A.; Ansseau, I. [Université Libre de Bruxelles, Science Faculty CP230, B-1050 Brussels (Belgium); Ahlers, M. [Department of Physics and Wisconsin IceCube Particle Astrophysics Center, University of Wisconsin, Madison, WI 53706 (United States); Ahrens, M. [Oskar Klein Centre and Department of Physics, Stockholm University, SE-10691 Stockholm (Sweden); Altmann, D.; Anton, G. [Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, D-91058 Erlangen (Germany); Andeen, K. [Department of Physics, Marquette University, Milwaukee, WI, 53201 (United States); Anderson, T.; Arlen, T. C. [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Archinger, M.; Baum, V. [Institute of Physics, University of Mainz, Staudinger Weg 7, D-55099 Mainz (Germany); Arguelles, C. [Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Auffenberg, J. [III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen (Germany); Bai, X. [Physics Department, South Dakota School of Mines and Technology, Rapid City, SD 57701 (United States); Barwick, S. W. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Bay, R., E-mail: jacob.feintzeig@gmail.com, E-mail: naoko@icecube.wisc.edu [Department of Physics, University of California, Berkeley, CA 94720 (United States); Collaboration: IceCube Collaboration; and others

    2016-06-20

    Observation of a point source of astrophysical neutrinos would be a “smoking gun” signature of a cosmic-ray accelerator. While IceCube has recently discovered a diffuse flux of astrophysical neutrinos, no localized point source has been observed. Previous IceCube searches for point sources in the southern sky were restricted by either an energy threshold above a few hundred TeV or poor neutrino angular resolution. Here we present a search for southern sky point sources with greatly improved sensitivities to neutrinos with energies below 100 TeV. By selecting charged-current ν{sub μ} interacting inside the detector, we reduce the atmospheric background while retaining efficiency for astrophysical neutrino-induced events reconstructed with sub-degree angular resolution. The new event sample covers three years of detector data and leads to a factor of 10 improvement in sensitivity to point sources emitting below 100 TeV in the southern sky. No statistically significant evidence of point sources was found, and upper limits are set on neutrino emission from individual sources. A posteriori analysis of the highest-energy (∼100 TeV) starting event in the sample found that this event alone represents a 2.8 σ deviation from the hypothesis that the data consists only of atmospheric background.

  9. CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES: THE SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song; Liu, Jifeng; Qiu, Yanli; Bai, Yu; Yang, Huiqin; Guo, Jincheng; Zhang, Peng, E-mail: jfliu@bao.ac.cn, E-mail: songw@bao.ac.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2016-06-01

    The Chandra archival data is a valuable resource for various studies on different X-ray astronomy topics. In this paper, we utilize this wealth of information and present a uniformly processed data set, which can be used to address a wide range of scientific questions. The data analysis procedures are applied to 10,029 Advanced CCD Imaging Spectrometer observations, which produces 363,530 source detections belonging to 217,828 distinct X-ray sources. This number is twice the size of the Chandra Source Catalog (Version 1.1). The catalogs in this paper provide abundant estimates of the detected X-ray source properties, including source positions, counts, colors, fluxes, luminosities, variability statistics, etc. Cross-correlation of these objects with galaxies shows that 17,828 sources are located within the D {sub 25} isophotes of 1110 galaxies, and 7504 sources are located between the D {sub 25} and 2 D {sub 25} isophotes of 910 galaxies. Contamination analysis with the log N –log S relation indicates that 51.3% of objects within 2 D {sub 25} isophotes are truly relevant to galaxies, and the “net” source fraction increases to 58.9%, 67.3%, and 69.1% for sources with luminosities above 10{sup 37}, 10{sup 38}, and 10{sup 39} erg s{sup −1}, respectively. Among the possible scientific uses of this catalog, we discuss the possibility of studying intra-observation variability, inter-observation variability, and supersoft sources (SSSs). About 17,092 detected sources above 10 counts are classified as variable in individual observation with the Kolmogorov–Smirnov (K–S) criterion ( P {sub K–S} < 0.01). There are 99,647 sources observed more than once and 11,843 sources observed 10 times or more, offering us a wealth of data with which to explore the long-term variability. There are 1638 individual objects (∼2350 detections) classified as SSSs. As a quite interesting subclass, detailed studies on X-ray spectra and optical spectroscopic follow-up are needed to

  10. Thermal Analysis of a Cracked Half-plane under Moving Point Heat Source

    Directory of Open Access Journals (Sweden)

    He Kuanfang

    2017-09-01

    Full Text Available The heat conduction in half-plane with an insulated crack subjected to moving point heat source is investigated. The analytical solution and the numerical means are combined to analyze the transient temperature distribution of a cracked half-plane under moving point heat source. The transient temperature distribution of the half plane structure under moving point heat source is obtained by the moving coordinate method firstly, then the heat conduction equation with thermal boundary of an insulated crack face is changed to singular integral equation by applying Fourier transforms and solved by the numerical method. The numerical examples of the temperature distribution on the cracked half-plane structure under moving point heat source are presented and discussed in detail.

  11. A method to analyze "source-sink" structure of non-point source pollution based on remote sensing technology.

    Science.gov (United States)

    Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui

    2013-11-01

    With the purpose of providing scientific basis for environmental planning about non-point source pollution prevention and control, and improving the pollution regulating efficiency, this paper established the Grid Landscape Contrast Index based on Location-weighted Landscape Contrast Index according to the "source-sink" theory. The spatial distribution of non-point source pollution caused by Jiulongjiang Estuary could be worked out by utilizing high resolution remote sensing images. The results showed that, the area of "source" of nitrogen and phosphorus in Jiulongjiang Estuary was 534.42 km(2) in 2008, and the "sink" was 172.06 km(2). The "source" of non-point source pollution was distributed mainly over Xiamen island, most of Haicang, east of Jiaomei and river bank of Gangwei and Shima; and the "sink" was distributed over southwest of Xiamen island and west of Shima. Generally speaking, the intensity of "source" gets weaker along with the distance from the seas boundary increase, while "sink" gets stronger. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Non point source pollution modelling in the watershed managed by Integrated Conctructed Wetlands: A GIS approach.

    OpenAIRE

    Vyavahare, Nilesh

    2008-01-01

    The non-point source pollution has been recognised as main cause of eutrophication in Ireland (EPA Ireland, 2001). Integrated Constructed Wetland (ICW) is a management practice adopted in Annestown stream watershed, located in the south county of Waterford in Ireland, used to cleanse farmyard runoff. Present study forms the annual pollution budget for the Annestown stream watershed. The amount of pollution from non-point sources flowing into the stream was simulated by using GIS techniques; u...

  13. Epidemiology, public health, and health surveillance around point sources of pollution

    International Nuclear Information System (INIS)

    Stebbings, J.H. Jr.

    1981-01-01

    In industrial society a large number of point sources of pollution exist, such as chemical plants, smelters, and nuclear power plants. Public concern has forced the practising epidemiologist to undertake health surveillance of the usually small populations living around point sources. Although not justifiable as research, such epidemiologic surveillance activities are becoming a routine part of public health practice, and this trend will continue. This introduction reviews concepts of epidemiologic surveillance, and institutional problems relating to the quality of such applied research

  14. Reduction of bias in neutron multiplicity assay using a weighted point model

    Energy Technology Data Exchange (ETDEWEB)

    Geist, W. H. (William H.); Krick, M. S. (Merlyn S.); Mayo, D. R. (Douglas R.)

    2004-01-01

    Accurate assay of most common plutonium samples was the development goal for the nondestructive assay technique of neutron multiplicity counting. Over the past 20 years the technique has been proven for relatively pure oxides and small metal items. Unfortunately, the technique results in large biases when assaying large metal items. Limiting assumptions, such as unifoh multiplication, in the point model used to derive the multiplicity equations causes these biases for large dense items. A weighted point model has been developed to overcome some of the limitations in the standard point model. Weighting factors are detemiined from Monte Carlo calculations using the MCNPX code. Monte Carlo calculations give the dependence of the weighting factors on sample mass and geometry, and simulated assays using Monte Carlo give the theoretical accuracy of the weighted-point-model assay. Measured multiplicity data evaluated with both the standard and weighted point models are compared to reference values to give the experimental accuracy of the assay. Initial results show significant promise for the weighted point model in reducing or eliminating biases in the neutron multiplicity assay of metal items. The negative biases observed in the assay of plutonium metal samples are caused by variations in the neutron multiplication for neutrons originating in various locations in the sample. The bias depends on the mass and shape of the sample and depends on the amount and energy distribution of the ({alpha},n) neutrons in the sample. When the standard point model is used, this variable-multiplication bias overestimates the multiplication and alpha values of the sample, and underestimates the plutonium mass. The weighted point model potentially can provide assay accuracy of {approx}2% (1 {sigma}) for cylindrical plutonium metal samples < 4 kg with {alpha} < 1 without knowing the exact shape of the samples, provided that the ({alpha},n) source is uniformly distributed throughout the

  15. The resolution of point sources of light as analyzed by quantum detection theory

    Science.gov (United States)

    Helstrom, C. W.

    1972-01-01

    The resolvability of point sources of incoherent light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

  16. Resolution of point sources of light as analyzed by quantum detection theory.

    Science.gov (United States)

    Helstrom, C. W.

    1973-01-01

    The resolvability of point sources of incoherent thermal light is analyzed by quantum detection theory in terms of two hypothesis-testing problems. In the first, the observer must decide whether there are two sources of equal radiant power at given locations, or whether there is only one source of twice the power located midway between them. In the second problem, either one, but not both, of two point sources is radiating, and the observer must decide which it is. The decisions are based on optimum processing of the electromagnetic field at the aperture of an optical instrument. In both problems the density operators of the field under the two hypotheses do not commute. The error probabilities, determined as functions of the separation of the points and the mean number of received photons, characterize the ultimate resolvability of the sources.

  17. Interferometry with flexible point source array for measuring complex freeform surface and its design algorithm

    Science.gov (United States)

    Li, Jia; Shen, Hua; Zhu, Rihong; Gao, Jinming; Sun, Yue; Wang, Jinsong; Li, Bo

    2018-06-01

    The precision of the measurements of aspheric and freeform surfaces remains the primary factor restrict their manufacture and application. One effective means of measuring such surfaces involves using reference or probe beams with angle modulation, such as tilted-wave-interferometer (TWI). It is necessary to improve the measurement efficiency by obtaining the optimum point source array for different pieces before TWI measurements. For purpose of forming a point source array based on the gradients of different surfaces under test, we established a mathematical model describing the relationship between the point source array and the test surface. However, the optimal point sources are irregularly distributed. In order to achieve a flexible point source array according to the gradient of test surface, a novel interference setup using fiber array is proposed in which every point source can be independently controlled on and off. Simulations and the actual measurement examples of two different surfaces are given in this paper to verify the mathematical model. Finally, we performed an experiment of testing an off-axis ellipsoidal surface that proved the validity of the proposed interference system.

  18. Characteristics of a multi-keV monochromatic point x-ray source

    Indian Academy of Sciences (India)

    Temporal, spatial and spectral characteristics of a multi-keV monochromatic point x-ray source based on vacuum diode with laser-produced plasma as cathode are presented. Electrons from a laser-produced aluminium plasma were accelerated towards a conical point tip titanium anode to generate K-shell x-ray radiation.

  19. Mapping correlation of a simulated dark matter source and a point source in the gamma-ray sky - Oral Presentation

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, Alexander [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-23

    In my research, I analyzed how two gamma-ray source models interact with one another when optimizing to fit data. This is important because it becomes hard to distinguish between the two point sources when they are close together or looking at low energy photons. The reason for the first is obvious, the reason why they become harder to distinguish at lower photon energies is the resolving power of the Fermi Gamma-Ray Space Telescope gets worse at lower energies. When the two point sources are highly correlated (hard to distinguish between), we need to change our method of statistical analysis. What I did was show that highly correlated sources have larger uncertainties associated with them, caused by an optimizer not knowing which point source’s parameters to optimize. I also mapped out where their is high correlation for 2 different theoretical mass dark matter point sources so that people analyzing them in the future knew where they had to use more sophisticated statistical analysis.

  20. Realtime Gas Emission Monitoring at Hazardous Sites Using a Distributed Point-Source Sensing Infrastructure

    Science.gov (United States)

    Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco

    2016-01-01

    This paper describes a distributed point-source monitoring platform for gas level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant’s critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events. PMID:26805832

  1. Realtime Gas Emission Monitoring at Hazardous Sites Using a Distributed Point-Source Sensing Infrastructure

    Directory of Open Access Journals (Sweden)

    Gianfranco Manes

    2016-01-01

    Full Text Available This paper describes a distributed point-source monitoring platform for gas level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN architecture, is organised into sub-networks to be positioned in the plant’s critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events.

  2. Realtime Gas Emission Monitoring at Hazardous Sites Using a Distributed Point-Source Sensing Infrastructure.

    Science.gov (United States)

    Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco

    2016-01-20

    This paper describes a distributed point-source monitoring platform for gas level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant's critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events.

  3. Economic Analysis of Nitrate Source Reductions in California Agriculture

    Science.gov (United States)

    Medellin-Azuara, J.; Howitt, R.; Rosenstock, T.; Harter, T.; Pettygrove, S. G.; Dzurella, K.; Lund, J. R.

    2011-12-01

    We present an analytical approach to assess the economic impact of improving nitrogen management practices in California agriculture. We employ positive mathematical programming to calibrate crop production to base input information. The production function representation is a nested constant elasticity of substitution with two nests: one for applied water and one for applied nitrogen. The first nest accounts for the tradeoffs between irrigation efficiency and capital investments in irrigation technology. The second nest represents the tradeoffs between nitrogen application efficiency and the marginal costs of improving nitrogen efficiency. In the production function nest, low elasticities of substitution and water and nitrogen stress constraints keep agricultural crop yields constant despite changes in nitrogen management practices. We use the Tulare Basin, and the Salinas Valley in California's Central Valley and Central Coast respectively as our case studies. Preliminary results show that initial reductions of 25% in nitrogen loads to groundwater may not impose large costs to agricultural crop production as substitution of management inputs results in only small declines in net revenue from farming and total land use. Larger reductions in the nitrogen load to groundwater of 50% imposes larger marginal costs for better nitrogen management inputs and reductions in the area of lower valued crops grown in the study areas. Despite the shortage of data on quantitative effects of improved nitrogen efficiency; our results demonstrate the potential of combining economic and agronomic data into a model that can reflect differences in cost and substitutabilty in nitrogen application methods, that can be used to reduce the quantity of nitrogen leaching into groundwater.

  4. THE DATA REDUCTION PIPELINE FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT

    International Nuclear Information System (INIS)

    Nidever, David L.; Holtzman, Jon A.; Prieto, Carlos Allende; Mészáros, Szabolcs; Beland, Stephane; Bender, Chad; Desphande, Rohit; Bizyaev, Dmitry; Burton, Adam; García Pérez, Ana E.; Hearty, Fred R.; Majewski, Steven R.; Skrutskie, Michael F.; Sobeck, Jennifer S.; Wilson, John C.; Fleming, Scott W.; Muna, Demitri; Nguyen, Duy; Schiavon, Ricardo P.; Shetrone, Matthew

    2015-01-01

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, explores the stellar populations of the Milky Way using the Sloan 2.5-m telescope linked to a high resolution (R ∼ 22,500), near-infrared (1.51–1.70 μm) spectrograph with 300 optical fibers. For over 150,000 predominantly red giant branch stars that APOGEE targeted across the Galactic bulge, disks and halo, the collected high signal-to-noise ratio (>100 per half-resolution element) spectra provide accurate (∼0.1 km s −1 ) RVs, stellar atmospheric parameters, and precise (≲0.1 dex) chemical abundances for about 15 chemical species. Here we describe the basic APOGEE data reduction software that reduces multiple 3D raw data cubes into calibrated, well-sampled, combined 1D spectra, as implemented for the SDSS-III/APOGEE data releases (DR10, DR11 and DR12). The processing of the near-IR spectral data of APOGEE presents some challenges for reduction, including automated sky subtraction and telluric correction over a 3°-diameter field and the combination of spectrally dithered spectra. We also discuss areas for future improvement

  5. THE DATA REDUCTION PIPELINE FOR THE APACHE POINT OBSERVATORY GALACTIC EVOLUTION EXPERIMENT

    Energy Technology Data Exchange (ETDEWEB)

    Nidever, David L. [Department of Astronomy, University of Michigan, Ann Arbor, MI 48109 (United States); Holtzman, Jon A. [New Mexico State University, Las Cruces, NM 88003 (United States); Prieto, Carlos Allende; Mészáros, Szabolcs [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Beland, Stephane [Laboratory for Atmospheric and Space Sciences, University of Colorado at Boulder, Boulder, CO (United States); Bender, Chad; Desphande, Rohit [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); Bizyaev, Dmitry [Apache Point Observatory and New Mexico State University, P.O. Box 59, sunspot, NM 88349-0059 (United States); Burton, Adam; García Pérez, Ana E.; Hearty, Fred R.; Majewski, Steven R.; Skrutskie, Michael F.; Sobeck, Jennifer S.; Wilson, John C. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Fleming, Scott W. [Computer Sciences Corporation, 3700 San Martin Dr, Baltimore, MD 21218 (United States); Muna, Demitri [Department of Astronomy and the Center for Cosmology and Astro-Particle Physics, The Ohio State University, Columbus, OH 43210 (United States); Nguyen, Duy [Department of Astronomy and Astrophysics, University of Toronto, Toronto, Ontario, M5S 3H4 (Canada); Schiavon, Ricardo P. [Gemini Observatory, 670 N. A’Ohoku Place, Hilo, HI 96720 (United States); Shetrone, Matthew, E-mail: dnidever@umich.edu [University of Texas at Austin, McDonald Observatory, Fort Davis, TX 79734 (United States)

    2015-12-15

    The Apache Point Observatory Galactic Evolution Experiment (APOGEE), part of the Sloan Digital Sky Survey III, explores the stellar populations of the Milky Way using the Sloan 2.5-m telescope linked to a high resolution (R ∼ 22,500), near-infrared (1.51–1.70 μm) spectrograph with 300 optical fibers. For over 150,000 predominantly red giant branch stars that APOGEE targeted across the Galactic bulge, disks and halo, the collected high signal-to-noise ratio (>100 per half-resolution element) spectra provide accurate (∼0.1 km s{sup −1}) RVs, stellar atmospheric parameters, and precise (≲0.1 dex) chemical abundances for about 15 chemical species. Here we describe the basic APOGEE data reduction software that reduces multiple 3D raw data cubes into calibrated, well-sampled, combined 1D spectra, as implemented for the SDSS-III/APOGEE data releases (DR10, DR11 and DR12). The processing of the near-IR spectral data of APOGEE presents some challenges for reduction, including automated sky subtraction and telluric correction over a 3°-diameter field and the combination of spectrally dithered spectra. We also discuss areas for future improvement.

  6. Reduction of NOx emission from stationary combustion sources

    International Nuclear Information System (INIS)

    Nelson, P.F.

    1992-01-01

    The environmental impacts of NO x emission from stationary combustion sources are briefly described. These include the formation of both acid rain and photochemical smog, major environmental problems. The three mechanisms which have been identified for the formation of NO x in combustion (thermal, prompt and fuel) are also briefly outlined. Recently stringent standards have been introduced to control emissions of NO x and the review describes the major primary and secondary measures. 10 refs. 2 tabs., 5 figs

  7. Miniature x-ray point source for alignment and calibration of x-ray optics

    International Nuclear Information System (INIS)

    Price, R.H.; Boyle, M.J.; Glaros, S.S.

    1977-01-01

    A miniature x-ray point source of high brightness similar to that of Rovinsky, et al. is described. One version of the x-ray source is used to align the x-ray optics on the Argus and Shiva laser systems. A second version is used to determine the spatial and spectral transmission functions of the x-ray optics. The spatial and spectral characteristics of the x-ray emission from the x-ray point source are described. The physical constraints including size, intensity and thermal limitations, and useful lifetime are discussed. The alignment and calibration techniques for various x-ray optics and detector combinations are described

  8. PSFGAN: a generative adversarial network system for separating quasar point sources and host galaxy light

    Science.gov (United States)

    Stark, Dominic; Launet, Barthelemy; Schawinski, Kevin; Zhang, Ce; Koss, Michael; Turp, M. Dennis; Sartori, Lia F.; Zhang, Hantian; Chen, Yiru; Weigel, Anna K.

    2018-06-01

    The study of unobscured active galactic nuclei (AGN) and quasars depends on the reliable decomposition of the light from the AGN point source and the extended host galaxy light. The problem is typically approached using parametric fitting routines using separate models for the host galaxy and the point spread function (PSF). We present a new approach using a Generative Adversarial Network (GAN) trained on galaxy images. We test the method using Sloan Digital Sky Survey r-band images with artificial AGN point sources added that are then removed using the GAN and with parametric methods using GALFIT. When the AGN point source is more than twice as bright as the host galaxy, we find that our method, PSFGAN, can recover point source and host galaxy magnitudes with smaller systematic error and a lower average scatter (49 per cent). PSFGAN is more tolerant to poor knowledge of the PSF than parametric methods. Our tests show that PSFGAN is robust against a broadening in the PSF width of ± 50 per cent if it is trained on multiple PSFs. We demonstrate that while a matched training set does improve performance, we can still subtract point sources using a PSFGAN trained on non-astronomical images. While initial training is computationally expensive, evaluating PSFGAN on data is more than 40 times faster than GALFIT fitting two components. Finally, PSFGAN is more robust and easy to use than parametric methods as it requires no input parameters.

  9. Guaranteed Unresolved Point Source Emission and the Gamma-ray Background

    International Nuclear Information System (INIS)

    Pavlidou, Vasiliki; Siegal-Gaskins, Jennifer M.; Brown, Carolyn; Fields, Brian D.; Olinto, Angela V.

    2007-01-01

    The large majority of EGRET point sources remain without an identified low-energy counterpart, and a large fraction of these sources are most likely extragalactic. Whatever the nature of the extragalactic EGRET unidentified sources, faint unresolved objects of the same class must have a contribution to the diffuse extragalactic gamma-ray background (EGRB). Understanding this component of the EGRB, along with other guaranteed contributions from known sources (blazars and normal galaxies), is essential if we are to use this emission to constrain exotic high-energy physics. Here, we follow an empirical approach to estimate whether the contribution of unresolved unidentified sources to the EGRB is likely to be important. Additionally, we discuss how upcoming GLAST observations of EGRET unidentified sources, their fainter counterparts, and the Galactic and extragalactic diffuse backgrounds, will shed light on the nature of the EGRET unidentified sources even without any positional association of such sources with low-energy counterparts

  10. Disaster Risk Reduction through Innovative Uses of Crowd Sourcing (Invited)

    Science.gov (United States)

    Berger, J.; Greene, M.

    2010-12-01

    Crowd sourcing can be described as a method of distributed problem-solving. It takes advantage of the power of the crowd, which can in some cases be a community of experts and in other cases the collective insight of a broader range of contributors with varying degrees of domain knowledge. The term crowd sourcing was first used by Jeff Howe in a June 2006 Wired magazine article “The Rise of Crowdsourcing,” and is a combination of the terms “crowd” and “outsourcing.” Some commonly known examples of crowd sourcing, in its broadest sense, include Wikepedia, distributed participatory design projects, and consumer websites such as Yelp and Angie’s List. The popularity and success of early large-scale crowd sourcing activities is made possible through leveraging Web 2.0 technologies that allow for mass participation from distributed individuals. The Earthquake Engineering Research Institute (EERI) in Oakland, California recently participated in two crowd sourcing projects. One was initiated and coordinated by EERI, while in the second case EERI was invited to contribute once the crowd sourcing activity was underway. In both projects there was: 1) the determination of a problem or set of tasks that could benefit immediately from the engagement of an informed volunteer group of professionals; 2) a segmenting of the problem into discrete pieces that could be completed in a short period of time (from ten minutes to four hours); 3) a call to action, where an interested community was made aware of the project; and 4) the collection, aggregation, vetting and ultimately distribution of the results in a relatively short period of time. The first EERI crowd sourcing example was the use of practicing engineers and engineering students in California to help estimate the number of pre-1980 concrete buildings in the high seismic risk counties in the state. This building type is known to perform poorly in earthquakes, and state officials were interested in understanding

  11. Evaluation of the Agricultural Non-point Source Pollution in Chongqing Based on PSR Model

    Institute of Scientific and Technical Information of China (English)

    Hanwen; ZHANG; Xinli; MOU; Hui; XIE; Hong; LU; Xingyun; YAN

    2014-01-01

    Through a series of exploration based on PSR framework model,for the purpose of building a suitable Chongqing agricultural nonpoint source pollution evaluation index system model framework,combined with the presence of Chongqing specific agro-environmental issues,we build a agricultural non-point source pollution assessment index system,and then study the agricultural system pressure,agro-environmental status and human response in total 3 major categories,develope an agricultural non-point source pollution evaluation index consisting of 3 criteria indicators and 19 indicators. As can be seen from the analysis,pressures and responses tend to increase and decrease linearly,state and complex have large fluctuations,and their fluctuations are similar mainly due to the elimination of pressures and impact,increasing the impact for agricultural non-point source pollution.

  12. Tackling non-point source water pollution in British Columbia: An action plan

    Energy Technology Data Exchange (ETDEWEB)

    1998-01-01

    Efforts to protect British Columbia water quality by regulating point discharges from municipal and industrial sources have generally been successful, and it is recognized that the major remaining cause of water pollution in the province is from non-point sources. These sources are largely unregulated and associated with urbanization, agriculture, and other forms of land development. The first part of this report reviews the provincial commitment to clean water, the effects of non-point-source (NPS) pollution, and the management of NPS in the province. Part 2 describes the main causes of NPS in British Columbia: Land development, agriculture, stormwater runoff, on-site sewage systems, forestry and range activities, atmospheric deposition, and boating/marine activities. Finally, it presents key components of the province's NPS action plan: Education and training, prevention at site, land use planning and co-ordination, assessment and reporting, economic incentives, legislation and regulation, and implementation.

  13. Extending the search for neutrino point sources with IceCube above the horizon

    Energy Technology Data Exchange (ETDEWEB)

    IceCube Collaboration; Abbasi, R.

    2009-11-20

    Point source searches with the IceCube neutrino telescope have been restricted to one hemisphere, due to the exclusive selection of upward going events as a way of rejecting the atmospheric muon background. We show that the region above the horizon can be included by suppressing the background through energy-sensitive cuts. This approach improves the sensitivity above PeV energies, previously not accessible for declinations of more than a few degrees below the horizon due to the absorption of neutrinos in Earth. We present results based on data collected with 22 strings of IceCube, extending its field of view and energy reach for point source searches. No significant excess above the atmospheric background is observed in a sky scan and in tests of source candidates. Upper limits are reported, which for the first time cover point sources in the southern sky up to EeV energies.

  14. Model Predictive Control of Z-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    2011-01-01

    This paper presents Model Predictive Control (MPC) of Z-source Neutral Point Clamped (NPC) inverter. For illustration, current control of Z-source NPC grid-connected inverter is analyzed and simulated. With MPC’s advantage of easily including system constraints, load current, impedance network...... response are obtained at the same time with a formulated Z-source NPC inverter network model. Operation steady state and transient state simulation results of MPC are going to be presented, which shows good reference tracking ability of this method. It provides new control method for Z-source NPC inverter...

  15. Double point source W-phase inversion: Real-time implementation and automated model selection

    Science.gov (United States)

    Nealy, Jennifer; Hayes, Gavin

    2015-01-01

    Rapid and accurate characterization of an earthquake source is an extremely important and ever evolving field of research. Within this field, source inversion of the W-phase has recently been shown to be an effective technique, which can be efficiently implemented in real-time. An extension to the W-phase source inversion is presented in which two point sources are derived to better characterize complex earthquakes. A single source inversion followed by a double point source inversion with centroid locations fixed at the single source solution location can be efficiently run as part of earthquake monitoring network operational procedures. In order to determine the most appropriate solution, i.e., whether an earthquake is most appropriately described by a single source or a double source, an Akaike information criterion (AIC) test is performed. Analyses of all earthquakes of magnitude 7.5 and greater occurring since January 2000 were performed with extended analyses of the September 29, 2009 magnitude 8.1 Samoa earthquake and the April 19, 2014 magnitude 7.5 Papua New Guinea earthquake. The AIC test is shown to be able to accurately select the most appropriate model and the selected W-phase inversion is shown to yield reliable solutions that match published analyses of the same events.

  16. PSFGAN: a generative adversarial network system for separating quasar point sources and host galaxy light

    Science.gov (United States)

    Stark, Dominic; Launet, Barthelemy; Schawinski, Kevin; Zhang, Ce; Koss, Michael; Turp, M. Dennis; Sartori, Lia F.; Zhang, Hantian; Chen, Yiru; Weigel, Anna K.

    2018-03-01

    The study of unobscured active galactic nuclei (AGN) and quasars depends on the reliable decomposition of the light from the AGN point source and the extended host galaxy light. The problem is typically approached using parametric fitting routines using separate models for the host galaxy and the point spread function (PSF). We present a new approach using a Generative Adversarial Network (GAN) trained on galaxy images. We test the method using Sloan Digital Sky Survey (SDSS) r-band images with artificial AGN point sources added which are then removed using the GAN and with parametric methods using GALFIT. When the AGN point source PS is more than twice as bright as the host galaxy, we find that our method, PSFGAN, can recover PS and host galaxy magnitudes with smaller systematic error and a lower average scatter (49%). PSFGAN is more tolerant to poor knowledge of the PSF than parametric methods. Our tests show that PSFGAN is robust against a broadening in the PSF width of ±50% if it is trained on multiple PSF's. We demonstrate that while a matched training set does improve performance, we can still subtract point sources using a PSFGAN trained on non-astronomical images. While initial training is computationally expensive, evaluating PSFGAN on data is more than 40 times faster than GALFIT fitting two components. Finally, PSFGAN it is more robust and easy to use than parametric methods as it requires no input parameters.

  17. Applicability of a desiccant dew-point cooling system independent of external water sources

    DEFF Research Database (Denmark)

    Bellemo, Lorenzo; Elmegaard, Brian; Kærn, Martin Ryhl

    2015-01-01

    The applicability of a technical solution for making desiccant cooling systems independent of external water sources is investigated. Water is produced by condensing the desorbed water vapour in a closed regeneration circuit. Desorbed water recovery is applied to a desiccant dew-point cooling...... system, which includes a desiccant wheel and a dew point cooler. The system is simulated during the summer period in the Mediterranean climate of Rome and it results completely independent of external water sources. The seasonal thermal COP drops 8% in comparison to the open regeneration circuit solution...

  18. Greenhouse Gas reduction for scenarios of power sources development of the Republic of Moldova

    Directory of Open Access Journals (Sweden)

    Comendant I.

    2010-04-01

    Full Text Available For the new power market conditions, Moldova power sources development options up to 2033 are evaluated, and for the six scenarios selected the greenhouse gas reduction impact is determined.

  19. X-ray Point Source Populations in Spiral and Elliptical Galaxies

    Science.gov (United States)

    Colbert, E.; Heckman, T.; Weaver, K.; Strickland, D.

    2002-01-01

    The hard-X-ray luminosity of non-active galaxies has been known to be fairly well correlated with the total blue luminosity since the days of the Einstein satellite. However, the origin of this hard component was not well understood. Some possibilities that were considered included X-ray binaries, extended upscattered far-infrared light via the inverse-Compton process, extended hot 107 K gas (especially in ellipitical galaxies), or even an active nucleus. Chandra images of normal, elliptical and starburst galaxies now show that a significant amount of the total hard X-ray emission comes from individual point sources. We present here spatial and spectral analyses of the point sources in a small sample of Chandra obervations of starburst galaxies, and compare with Chandra point source analyses from comparison galaxies (elliptical, Seyfert and normal galaxies). We discuss possible relationships between the number and total hard luminosity of the X-ray point sources and various measures of the galaxy star formation rate, and discuss possible options for the numerous compact sources that are observed.

  20. Watershed-based point sources permitting strategy and dynamic permit-trading analysis.

    Science.gov (United States)

    Ning, Shu-Kuang; Chang, Ni-Bin

    2007-09-01

    Permit-trading policy in a total maximum daily load (TMDL) program may provide an additional avenue to produce environmental benefit, which closely approximates what would be achieved through a command and control approach, with relatively lower costs. One of the important considerations that might affect the effective trading mechanism is to determine the dynamic transaction prices and trading ratios in response to seasonal changes of assimilative capacity in the river. Advanced studies associated with multi-temporal spatially varied trading ratios among point sources to manage water pollution hold considerable potential for industries and policy makers alike. This paper aims to present an integrated simulation and optimization analysis for generating spatially varied trading ratios and evaluating seasonal transaction prices accordingly. It is designed to configure a permit-trading structure basin-wide and provide decision makers with a wealth of cost-effective, technology-oriented, risk-informed, and community-based management strategies. The case study, seamlessly integrating a QUAL2E simulation model with an optimal waste load allocation (WLA) scheme in a designated TMDL study area, helps understand the complexity of varying environmental resources values over space and time. The pollutants of concern in this region, which are eligible for trading, mainly include both biochemical oxygen demand (BOD) and ammonia-nitrogen (NH3-N). The problem solution, as a consequence, suggests an array of waste load reduction targets in a well-defined WLA scheme and exhibits a dynamic permit-trading framework among different sub-watersheds in the study area. Research findings gained in this paper may extend to any transferable dynamic-discharge permit (TDDP) program worldwide.

  1. Nonpoint and Point Sources of Nitrogen in Major Watersheds of the United States

    Science.gov (United States)

    Puckett, Larry J.

    1994-01-01

    Estimates of nonpoint and point sources of nitrogen were made for 107 watersheds located in the U.S. Geological Survey's National Water-Quality Assessment Program study units throughout the conterminous United States. The proportions of nitrogen originating from fertilizer, manure, atmospheric deposition, sewage, and industrial sources were found to vary with climate, hydrologic conditions, land use, population, and physiography. Fertilizer sources of nitrogen are proportionally greater in agricultural areas of the West and the Midwest than in other parts of the Nation. Animal manure contributes large proportions of nitrogen in the South and parts of the Northeast. Atmospheric deposition of nitrogen is generally greatest in areas of greatest precipitation, such as the Northeast. Point sources (sewage and industrial) generally are predominant in watersheds near cities, where they may account for large proportions of the nitrogen in streams. The transport of nitrogen in streams increases as amounts of precipitation and runoff increase and is greatest in the Northeastern United States. Because no single nonpoint nitrogen source is dominant everywhere, approaches to control nitrogen must vary throughout the Nation. Watershed-based approaches to understanding nonpoint and point sources of contamination, as used by the National Water-Quality Assessment Program, will aid water-quality and environmental managers to devise methods to reduce nitrogen pollution.

  2. The Unicellular State as a Point Source in a Quantum Biological System

    Directory of Open Access Journals (Sweden)

    John S. Torday

    2016-05-01

    Full Text Available A point source is the central and most important point or place for any group of cohering phenomena. Evolutionary development presumes that biological processes are sequentially linked, but neither directed from, nor centralized within, any specific biologic structure or stage. However, such an epigenomic entity exists and its transforming effects can be understood through the obligatory recapitulation of all eukaryotic lifeforms through a zygotic unicellular phase. This requisite biological conjunction can now be properly assessed as the focal point of reconciliation between biology and quantum phenomena, illustrated by deconvoluting complex physiologic traits back to their unicellular origins.

  3. Investigating the effects of point source and nonpoint source pollution on the water quality of the East River (Dongjiang) in South China

    Science.gov (United States)

    Wu, Yiping; Chen, Ji

    2013-01-01

    Understanding the physical processes of point source (PS) and nonpoint source (NPS) pollution is critical to evaluate river water quality and identify major pollutant sources in a watershed. In this study, we used the physically-based hydrological/water quality model, Soil and Water Assessment Tool, to investigate the influence of PS and NPS pollution on the water quality of the East River (Dongjiang in Chinese) in southern China. Our results indicate that NPS pollution was the dominant contribution (>94%) to nutrient loads except for mineral phosphorus (50%). A comprehensive Water Quality Index (WQI) computed using eight key water quality variables demonstrates that water quality is better upstream than downstream despite the higher level of ammonium nitrogen found in upstream waters. Also, the temporal (seasonal) and spatial distributions of nutrient loads clearly indicate the critical time period (from late dry season to early wet season) and pollution source areas within the basin (middle and downstream agricultural lands), which resource managers can use to accomplish substantial reduction of NPS pollutant loadings. Overall, this study helps our understanding of the relationship between human activities and pollutant loads and further contributes to decision support for local watershed managers to protect water quality in this region. In particular, the methods presented such as integrating WQI with watershed modeling and identifying the critical time period and pollutions source areas can be valuable for other researchers worldwide.

  4. KM3NeT/ARCA sensitivity and discovery potential for neutrino point-like sources

    Directory of Open Access Journals (Sweden)

    Trovato A.

    2016-01-01

    Full Text Available KM3NeT is a large research infrastructure with a network of deep-sea neutrino telescopes in the abyss of the Mediterranean Sea. Of these, the KM3NeT/ARCA detector, installed in the KM3NeT-It node of the network, is optimised for studying high-energy neutrinos of cosmic origin. Sensitivities to galactic sources such as the supernova remnant RXJ1713.7-3946 and the pulsar wind nebula Vela X are presented as well as sensitivities to a generic point source with an E−2 spectrum which represents an approximation for the spectrum of extragalactic candidate neutrino sources.

  5. Systematic Review: Impact of point sources on antibiotic-resistant bacteria in the natural environment.

    Science.gov (United States)

    Bueno, I; Williams-Nguyen, J; Hwang, H; Sargeant, J M; Nault, A J; Singer, R S

    2018-02-01

    Point sources such as wastewater treatment plants and agricultural facilities may have a role in the dissemination of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG). To analyse the evidence for increases in ARB in the natural environment associated with these point sources of ARB and ARG, we conducted a systematic review. We evaluated 5,247 records retrieved through database searches, including both studies that ascertained ARG and ARB outcomes. All studies were subjected to a screening process to assess relevance to the question and methodology to address our review question. A risk of bias assessment was conducted upon the final pool of studies included in the review. This article summarizes the evidence only for those studies with ARB outcomes (n = 47). Thirty-five studies were at high (n = 11) or at unclear (n = 24) risk of bias in the estimation of source effects due to lack of information and/or failure to control for confounders. Statistical analysis was used in ten studies, of which one assessed the effect of multiple sources using modelling approaches; none reported effect measures. Most studies reported higher ARB prevalence or concentration downstream/near the source. However, this evidence was primarily descriptive and it could not be concluded that there is a clear impact of point sources on increases in ARB in the environment. To quantify increases in ARB in the environment due to specific point sources, there is a need for studies that stress study design, control of biases and analytical tools to provide effect measure estimates. © 2017 Blackwell Verlag GmbH.

  6. Nature of the Diffuse Source and Its Central Point-like Source in SNR 0509–67.5

    Energy Technology Data Exchange (ETDEWEB)

    Litke, Katrina C.; Chu, You-Hua; Holmes, Abigail; Santucci, Robert; Blindauer, Terrence; Gruendl, Robert A.; Ricker, Paul M. [Astronomy Department, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Li, Chuan-Jui [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan, R.O.C. (China); Pan, Kuo-Chuan [Departement Physik, Universität Basel, Klingelbergstrasse 82, CH-4056 Basel (Switzerland); Weisz, Daniel R., E-mail: kclitke@email.arizona.edu [Department of Astronomy, University of California, 501 Cambell Hall #3411, Berkeley, CA 94720-3411 (United States)

    2017-03-10

    We examine a diffuse emission region near the center of SNR 0509−67.5 to determine its nature. Within this diffuse region we observe a point-like source that is bright in the near-IR, but is not visible in the B and V bands. We consider an emission line observed at 6766 Å and the possibilities that it is Ly α , H α , and [O ii] λ 3727. We examine the spectral energy distribution (SED) of the source, comprised of Hubble Space Telescope B , V , I , J , and H bands in addition to Spitzer /IRAC 3.6, 4.5, 5.8, and 8 μ m bands. The peak of the SED is consistent with a background galaxy at z ≈ 0.8 ± 0.2 and a possible Balmer jump places the galaxy at z ≈ 0.9 ± 0.3. These SED considerations support the emission line’s identification as [O ii] λ 3727. We conclude that the diffuse source in SNR 0509−67.5 is a background galaxy at z ≈ 0.82. Furthermore, we identify the point-like source superposed near the center of the galaxy as its central bulge. Finally, we find no evidence for a surviving companion star, indicating a double-degenerate origin for SNR 0509−67.5.

  7. Nature of the Diffuse Source and Its Central Point-like Source in SNR 0509–67.5

    International Nuclear Information System (INIS)

    Litke, Katrina C.; Chu, You-Hua; Holmes, Abigail; Santucci, Robert; Blindauer, Terrence; Gruendl, Robert A.; Ricker, Paul M.; Li, Chuan-Jui; Pan, Kuo-Chuan; Weisz, Daniel R.

    2017-01-01

    We examine a diffuse emission region near the center of SNR 0509−67.5 to determine its nature. Within this diffuse region we observe a point-like source that is bright in the near-IR, but is not visible in the B and V bands. We consider an emission line observed at 6766 Å and the possibilities that it is Ly α , H α , and [O ii] λ 3727. We examine the spectral energy distribution (SED) of the source, comprised of Hubble Space Telescope B , V , I , J , and H bands in addition to Spitzer /IRAC 3.6, 4.5, 5.8, and 8 μ m bands. The peak of the SED is consistent with a background galaxy at z ≈ 0.8 ± 0.2 and a possible Balmer jump places the galaxy at z ≈ 0.9 ± 0.3. These SED considerations support the emission line’s identification as [O ii] λ 3727. We conclude that the diffuse source in SNR 0509−67.5 is a background galaxy at z ≈ 0.82. Furthermore, we identify the point-like source superposed near the center of the galaxy as its central bulge. Finally, we find no evidence for a surviving companion star, indicating a double-degenerate origin for SNR 0509−67.5.

  8. Effect of tissue inhomogeneity on dose distribution of point sources of low-energy electrons

    International Nuclear Information System (INIS)

    Kwok, C.S.; Bialobzyski, P.J.; Yu, S.K.; Prestwich, W.V.

    1990-01-01

    Perturbation in dose distributions of point sources of low-energy electrons at planar interfaces of cortical bone (CB) and red marrow (RM) was investigated experimentally and by Monte Carlo codes EGS and the TIGER series. Ultrathin LiF thermoluminescent dosimeters were used to measure the dose distributions of point sources of 204 Tl and 147 Pm in RM. When the point sources were at 12 mg/cm 2 from a planar interface of CB and RM equivalent plastics, dose enhancement ratios in RM averaged over the region 0--12 mg/cm 2 from the interface were measured to be 1.08±0.03 (SE) and 1.03±0.03 (SE) for 204 Tl and 147 Pm, respectively. The Monte Carlo codes predicted 1.05±0.02 and 1.01±0.02 for the two nuclides, respectively. However, EGS gave consistently 3% higher dose in the dose scoring region than the TIGER series when point sources of monoenergetic electrons up to 0.75 MeV energy were considered in the homogeneous RM situation or in the CB and RM heterogeneous situation. By means of the TIGER series, it was demonstrated that aluminum, which is normally assumed to be equivalent to CB in radiation dosimetry, leads to an overestimation of backscattering of low-energy electrons in soft tissue at a CB--soft-tissue interface by as much as a factor of 2

  9. Identification and quantification of point sources of surface water contamination in fruit culture in the Netherlands

    NARCIS (Netherlands)

    Wenneker, M.; Beltman, W.H.J.; Werd, de H.A.E.; Zande, van de J.C.

    2008-01-01

    Measurements of pesticide concentrations in surface water by the water boards show that they have decreased less than was expected from model calculations. Possibly, the implementation of spray drift reducing techniques is overestimated in the model calculation. The impact of point sources is

  10. General Approach to the Evolution of Singlet Nanoparticles from a Rapidly Quenched Point Source

    NARCIS (Netherlands)

    Feng, J.; Huang, Luyi; Ludvigsson, Linus; Messing, Maria; Maiser, A.; Biskos, G.; Schmidt-Ott, A.

    2016-01-01

    Among the numerous point vapor sources, microsecond-pulsed spark ablation at atmospheric pressure is a versatile and environmentally friendly method for producing ultrapure inorganic nanoparticles ranging from singlets having sizes smaller than 1 nm to larger agglomerated structures. Due to its fast

  11. HYDROLOGY AND SEDIMENT MODELING USING THE BASINS NON-POINT SOURCE MODEL

    Science.gov (United States)

    The Non-Point Source Model (Hydrologic Simulation Program-Fortran, or HSPF) within the EPA Office of Water's BASINS watershed modeling system was used to simulate streamflow and total suspended solids within Contentnea Creek, North Carolina, which is a tributary of the Neuse Rive...

  12. ''Anomalous'' air showers from point sources: Mass limits and light curves

    International Nuclear Information System (INIS)

    Domokos, G.; Elliott, B.; Kovesi-Domokos, S.

    1993-01-01

    We describe a method to obtain upper limits on the mass of the primaries of air showers associated with point sources. One also obtains the UHE pulse shape of a pulsar if its period is observed in the signal. As an example, we analyze the data obtained during a recent burst of Hercules-X1

  13. A search for hot post-AGE stars in the IRAS Point Source Catalog

    NARCIS (Netherlands)

    Oudmaijer, RD

    In this paper a first step is made to search for hot post-AGB stars in the IRAS Point Source Catalog. In order to find objects that evolved off the AGE a longer time ago than post-AGB objects discussed in the literature, objects that were not detected at 12 mu m by IRAS were selected. The selection

  14. Estimation of Methane Emissions from Municipal Solid Waste Landfills in China Based on Point Emission Sources

    Directory of Open Access Journals (Sweden)

    Cai Bo-Feng

    2014-01-01

    Citation: Cai, B.-F., Liu, J.-G., Gao, Q.-X., et al., 2014. Estimation of methane emissions from municipal solid waste landfills in China based on point emission sources. Adv. Clim. Change Res. 5(2, doi: 10.3724/SP.J.1248.2014.081.

  15. Comparative Evaluation of Pulsewidth Modulation Strategies for Z-Source Neutral-Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Loh, P.C.; Blaabjerg, Frede; Wong, C.P.

    2007-01-01

    modulation (PWM) strategies for controlling the Z-source NPC inverter. While developing the PWM techniques, attention has been devoted to carefully derive them from a common generic basis for improved portability, easier implementation, and most importantly, assisting readers in understanding all concepts......Z-source neutral-point-clamped (NPC) inverter has recently been proposed as an alternative three-level buck-boost power conversion solution with an improved output waveform quality. In principle, the designed Z-source inverter functions by selectively "shooting through" its power sources, coupled...... to the inverter using two unique Z-source impedance networks, to boost the inverter three-level output waveform. Proper modulation of the new inverter would therefore require careful integration of the selective shoot-through process to the basic switching concepts to achieve maximal voltage-boost, minimal...

  16. The Potential for Electrofuels Production in Sweden Utilizing Fossil and Biogenic CO2 Point Sources

    International Nuclear Information System (INIS)

    Hansson, Julia; Hackl, Roman; Taljegard, Maria; Brynolf, Selma; Grahn, Maria

    2017-01-01

    This paper maps, categorizes, and quantifies all major point sources of carbon dioxide (CO 2 ) emissions from industrial and combustion processes in Sweden. The paper also estimates the Swedish technical potential for electrofuels (power-to-gas/fuels) based on carbon capture and utilization. With our bottom-up approach using European databases, we find that Sweden emits approximately 50 million metric tons of CO 2 per year from different types of point sources, with 65% (or about 32 million tons) from biogenic sources. The major sources are the pulp and paper industry (46%), heat and power production (23%), and waste treatment and incineration (8%). Most of the CO 2 is emitted at low concentrations (<15%) from sources in the southern part of Sweden where power demand generally exceeds in-region supply. The potentially recoverable emissions from all the included point sources amount to 45 million tons. If all the recoverable CO 2 were used to produce electrofuels, the yield would correspond to 2–3 times the current Swedish demand for transportation fuels. The electricity required would correspond to about 3 times the current Swedish electricity supply. The current relatively few emission sources with high concentrations of CO 2 (>90%, biofuel operations) would yield electrofuels corresponding to approximately 2% of the current demand for transportation fuels (corresponding to 1.5–2 TWh/year). In a 2030 scenario with large-scale biofuels operations based on lignocellulosic feedstocks, the potential for electrofuels production from high-concentration sources increases to 8–11 TWh/year. Finally, renewable electricity and production costs, rather than CO 2 supply, limit the potential for production of electrofuels in Sweden.

  17. Tackling non-point source water pollution in British Columbia : an action plan

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    British Columbia`s approach to water quality management is discussed. The BC efforts include regulating `end of pipe` point discharges from industrial and municipal outfalls. The major remaining cause of water pollution is from non-point sources (NPS). NPS water pollution is caused by the release of pollutants from different and diffuse sources, mostly unregulated and associated with urbanization, agriculture and other forms of land development. The importance of dealing with such problems on an immediate basis to avoid a decline in water quality in the province is emphasized. Major sources of water pollution in British Columbia include: land development, agriculture, storm water runoff, onsite sewage systems, forestry, atmospheric deposition, and marine activities. 3 tabs.

  18. Strategies for satellite-based monitoring of CO2 from distributed area and point sources

    Science.gov (United States)

    Schwandner, Florian M.; Miller, Charles E.; Duren, Riley M.; Natraj, Vijay; Eldering, Annmarie; Gunson, Michael R.; Crisp, David

    2014-05-01

    Atmospheric CO2 budgets are controlled by the strengths, as well as the spatial and temporal variabilities of CO2 sources and sinks. Natural CO2 sources and sinks are dominated by the vast areas of the oceans and the terrestrial biosphere. In contrast, anthropogenic and geogenic CO2 sources are dominated by distributed area and point sources, which may constitute as much as 70% of anthropogenic (e.g., Duren & Miller, 2012), and over 80% of geogenic emissions (Burton et al., 2013). Comprehensive assessments of CO2 budgets necessitate robust and highly accurate satellite remote sensing strategies that address the competing and often conflicting requirements for sampling over disparate space and time scales. Spatial variability: The spatial distribution of anthropogenic sources is dominated by patterns of production, storage, transport and use. In contrast, geogenic variability is almost entirely controlled by endogenic geological processes, except where surface gas permeability is modulated by soil moisture. Satellite remote sensing solutions will thus have to vary greatly in spatial coverage and resolution to address distributed area sources and point sources alike. Temporal variability: While biogenic sources are dominated by diurnal and seasonal patterns, anthropogenic sources fluctuate over a greater variety of time scales from diurnal, weekly and seasonal cycles, driven by both economic and climatic factors. Geogenic sources typically vary in time scales of days to months (geogenic sources sensu stricto are not fossil fuels but volcanoes, hydrothermal and metamorphic sources). Current ground-based monitoring networks for anthropogenic and geogenic sources record data on minute- to weekly temporal scales. Satellite remote sensing solutions would have to capture temporal variability through revisit frequency or point-and-stare strategies. Space-based remote sensing offers the potential of global coverage by a single sensor. However, no single combination of orbit

  19. A Single Phase Doubly Grounded Semi-Z-Source Inverter for Photovoltaic (PV Systems with Maximum Power Point Tracking (MPPT

    Directory of Open Access Journals (Sweden)

    Tofael Ahmed

    2014-06-01

    Full Text Available In this paper, a single phase doubly grounded semi-Z-source inverter with maximum power point tracking (MPPT is proposed for photovoltaic (PV systems. This proposed system utilizes a single-ended primary inductor (SEPIC converter as DC-DC converter to implement the MPPT algorithm for tracking the maximum power from a PV array and a single phase semi-Z-source inverter for integrating the PV with AC power utilities. The MPPT controller utilizes a fast-converging algorithm to track the maximum power point (MPP and the semi-Z-source inverter utilizes a nonlinear SPWM to produce sinusoidal voltage at the output. The proposed system is able to track the MPP of PV arrays and produce an AC voltage at its output by utilizing only three switches. Experimental results show that the fast-converging MPPT algorithm has fast tracking response with appreciable MPP efficiency. In addition, the inverter shows the minimization of common mode leakage current with its ground sharing feature and reduction of the THD as well as DC current components at the output during DC-AC conversion.

  20. Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

    OpenAIRE

    Marpaung, T

    2012-01-01

    In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS), due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed ...

  1. [Nitrogen non-point source pollution identification based on ArcSWAT in Changle River].

    Science.gov (United States)

    Deng, Ou-Ping; Sun, Si-Yang; Lü, Jun

    2013-04-01

    The ArcSWAT (Soil and Water Assessment Tool) model was adopted for Non-point source (NPS) nitrogen pollution modeling and nitrogen source apportionment for the Changle River watershed, a typical agricultural watershed in Southeast China. Water quality and hydrological parameters were monitored, and the watershed natural conditions (including soil, climate, land use, etc) and pollution sources information were also investigated and collected for SWAT database. The ArcSWAT model was established in the Changle River after the calibrating and validating procedures of the model parameters. Based on the validated SWAT model, the contributions of different nitrogen sources to river TN loading were quantified, and spatial-temporal distributions of NPS nitrogen export to rivers were addressed. The results showed that in the Changle River watershed, Nitrogen fertilizer, nitrogen air deposition and nitrogen soil pool were the prominent pollution sources, which contributed 35%, 32% and 25% to the river TN loading, respectively. There were spatial-temporal variations in the critical sources for NPS TN export to the river. Natural sources, such as soil nitrogen pool and atmospheric nitrogen deposition, should be targeted as the critical sources for river TN pollution during the rainy seasons. Chemical nitrogen fertilizer application should be targeted as the critical sources for river TN pollution during the crop growing season. Chemical nitrogen fertilizer application, soil nitrogen pool and atmospheric nitrogen deposition were the main sources for TN exported from the garden plot, forest and residential land, respectively. However, they were the main sources for TN exported both from the upland and paddy field. These results revealed that NPS pollution controlling rules should focus on the spatio-temporal distribution of NPS pollution sources.

  2. An extended dual input dual output three level Z source inverter with improved switch loss reduction technique

    Directory of Open Access Journals (Sweden)

    N.B. Deshmukh

    2016-12-01

    Full Text Available Multilevel inverter (MLI is a proven technology used for industrial applications due to low output total harmonic distortion (THD, high power handling capability and low active device rating. Dual output inverter is a recent trend associated with inverter topologies for specialized applications. This paper deals with three phase three level dual input dual output inverter topology with minimum active device count. Reduction in switch count leads to reduction in losses and improves reliability. Both the input sources share power equally as neutral point current ripple is maintained low. For further reduction in switching losses at higher switching frequencies, the concept of “no switching zone” or discontinuous pulse width modulation (DPWM has been put forth recently. This paper proposes modification in the placement of “no switching zone” in order to optimize switching losses and output THD (output filtering requirements for low power factor load. This study also proposes novel graphical approach to analyze the loss reduction along with its effect on output THD. The sinusoidal PWM (SPWM is used which gives satisfactory switching loss reduction without complex calculations. Moreover, the proposed topology is generalized to provide dual output at higher voltage levels. It is seen that the components reduction phenomenon becomes more pronounced as number of levels goes on increasing. The proposed converter is simulated in MATLAB software environment and results are obtained.

  3. A Targeted Search for Point Sources of EeV Photons with the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Aab, A. [Institute for Mathematics, Astrophysics and Particle Physics (IMAPP), Radboud Universiteit, Nijmegen (Netherlands); Abreu, P. [Laboratório de Instrumentação e Física Experimental de Partículas—LIP and Instituto Superior Técnico—IST, Universidade de Lisboa—UL, Lisbon (Portugal); Aglietta, M. [INFN, Sezione di Torino, Torino (Italy); Samarai, I. Al [Laboratoire de Physique Nucléaire et de Hautes Energies (LPNHE), Universités Paris 6 et Paris 7, CNRS-IN2P3, Paris (France); Albuquerque, I. F. M. [Universidade de São Paulo, Inst. de Física, São Paulo (Brazil); Allekotte, I. [Centro Atómico Bariloche and Instituto Balseiro (CNEA-UNCuyo-CONICET), San Carlos de Bariloche (Argentina); Almela, A. [Instituto de Tecnologías en Detección y Astropartículas (CNEA, CONICET, UNSAM), Centro Atómico Constituyentes, Comisión Nacional de Energía Atómica, Buenos Aires (Argentina); Castillo, J. Alvarez [Universidad Nacional Autónoma de México, México, D. F., México (Mexico); Alvarez-Muñiz, J. [Universidad de Santiago de Compostela, La Coruña (Spain); Anastasi, G. A. [Gran Sasso Science Institute (INFN), L’Aquila (Italy); and others

    2017-03-10

    Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined p -values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. These limits significantly constrain predictions of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.

  4. Identification of 'Point A' as the prevalent source of error in cephalometric analysis of lateral radiographs.

    Science.gov (United States)

    Grogger, P; Sacher, C; Weber, S; Millesi, G; Seemann, R

    2018-04-10

    Deviations in measuring dentofacial components in a lateral X-ray represent a major hurdle in the subsequent treatment of dysgnathic patients. In a retrospective study, we investigated the most prevalent source of error in the following commonly used cephalometric measurements: the angles Sella-Nasion-Point A (SNA), Sella-Nasion-Point B (SNB) and Point A-Nasion-Point B (ANB); the Wits appraisal; the anteroposterior dysplasia indicator (APDI); and the overbite depth indicator (ODI). Preoperative lateral radiographic images of patients with dentofacial deformities were collected and the landmarks digitally traced by three independent raters. Cephalometric analysis was automatically performed based on 1116 tracings. Error analysis identified the x-coordinate of Point A as the prevalent source of error in all investigated measurements, except SNB, in which it is not incorporated. In SNB, the y-coordinate of Nasion predominated error variance. SNB showed lowest inter-rater variation. In addition, our observations confirmed previous studies showing that landmark identification variance follows characteristic error envelopes in the highest number of tracings analysed up to now. Variance orthogonal to defining planes was of relevance, while variance parallel to planes was not. Taking these findings into account, orthognathic surgeons as well as orthodontists would be able to perform cephalometry more accurately and accomplish better therapeutic results. Copyright © 2018 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  5. Using Soluble Reactive Phosphorus and Ammonia to Identify Point Source Discharge from Large Livestock Facilities

    Science.gov (United States)

    Borrello, M. C.; Scribner, M.; Chessin, K.

    2013-12-01

    A growing body of research draws attention to the negative environmental impacts on surface water from large livestock facilities. These impacts are mostly in the form of excessive nutrient loading resulting in significantly decreased oxygen levels. Over-application of animal waste on fields as well as direct discharge into surface water from facilities themselves has been identified as the main contributor to the development of hypoxic zones in Lake Erie, Chesapeake Bay and the Gulf of Mexico. Some regulators claim enforcement of water quality laws is problematic because of the nature and pervasiveness of non-point source impacts. Any direct discharge by a facility is a violation of permits governed by the Clean Water Act, unless the facility has special dispensation for discharge. Previous research by the principal author and others has shown runoff and underdrain transport are the main mechanisms by which nutrients enter surface water. This study utilized previous work to determine if the effects of non-point source discharge can be distinguished from direct (point-source) discharge using simple nutrient analysis and dissolved oxygen (DO) parameters. Nutrient and DO parameters were measured from three sites: 1. A stream adjacent to a field receiving manure, upstream of a large livestock facility with a history of direct discharge, 2. The same stream downstream of the facility and 3. A stream in an area relatively unimpacted by large-scale agriculture (control site). Results show that calculating a simple Pearson correlation coefficient (r) of soluble reactive phosphorus (SRP) and ammonia over time as well as temperature and DO, distinguishes non-point source from point source discharge into surface water. The r value for SRP and ammonia for the upstream site was 0.01 while the r value for the downstream site was 0.92. The control site had an r value of 0.20. Likewise, r values were calculated on temperature and DO for each site. High negative correlations

  6. Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

    CERN Document Server

    Lu Cun Heng

    1999-01-01

    It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving cou...

  7. An international point source outbreak of typhoid fever: a European collaborative investigation*

    Science.gov (United States)

    Stanwell-Smith, R. E.; Ward, L. R.

    1986-01-01

    A point source outbreak of Salmonella typhi, degraded Vi-strain 22, affecting 32 British visitors to Kos, Greece, in 1983 was attributed by a case—control study to the consumption of a salad at one hotel. This represents the first major outbreak of typhoid fever in which a salad has been identified as the vehicle. The source of the infection was probably a carrier in the hotel staff. The investigation demonstrates the importance of national surveillance, international cooperation, and epidemiological methods in the investigation and control of major outbreaks of infection. PMID:3488842

  8. LEAP: Looking beyond pixels with continuous-space EstimAtion of Point sources

    Science.gov (United States)

    Pan, Hanjie; Simeoni, Matthieu; Hurley, Paul; Blu, Thierry; Vetterli, Martin

    2017-12-01

    Context. Two main classes of imaging algorithms have emerged in radio interferometry: the CLEAN algorithm and its multiple variants, and compressed-sensing inspired methods. They are both discrete in nature, and estimate source locations and intensities on a regular grid. For the traditional CLEAN-based imaging pipeline, the resolution power of the tool is limited by the width of the synthesized beam, which is inversely proportional to the largest baseline. The finite rate of innovation (FRI) framework is a robust method to find the locations of point-sources in a continuum without grid imposition. The continuous formulation makes the FRI recovery performance only dependent on the number of measurements and the number of sources in the sky. FRI can theoretically find sources below the perceived tool resolution. To date, FRI had never been tested in the extreme conditions inherent to radio astronomy: weak signal / high noise, huge data sets, large numbers of sources. Aims: The aims were (i) to adapt FRI to radio astronomy, (ii) verify it can recover sources in radio astronomy conditions with more accurate positioning than CLEAN, and possibly resolve some sources that would otherwise be missed, (iii) show that sources can be found using less data than would otherwise be required to find them, and (iv) show that FRI does not lead to an augmented rate of false positives. Methods: We implemented a continuous domain sparse reconstruction algorithm in Python. The angular resolution performance of the new algorithm was assessed under simulation, and with visibility measurements from the LOFAR telescope. Existing catalogs were used to confirm the existence of sources. Results: We adapted the FRI framework to radio interferometry, and showed that it is possible to determine accurate off-grid point-source locations and their corresponding intensities. In addition, FRI-based sparse reconstruction required less integration time and smaller baselines to reach a comparable

  9. High frequency seismic signal generated by landslides on complex topographies: from point source to spatially distributed sources

    Science.gov (United States)

    Mangeney, A.; Kuehnert, J.; Capdeville, Y.; Durand, V.; Stutzmann, E.; Kone, E. H.; Sethi, S.

    2017-12-01

    During their flow along the topography, landslides generate seismic waves in a wide frequency range. These so called landquakes can be recorded at very large distances (a few hundreds of km for large landslides). The recorded signals depend on the landslide seismic source and the seismic wave propagation. If the wave propagation is well understood, the seismic signals can be inverted for the seismic source and thus can be used to get information on the landslide properties and dynamics. Analysis and modeling of long period seismic signals (10-150s) have helped in this way to discriminate between different landslide scenarios and to constrain rheological parameters (e.g. Favreau et al., 2010). This was possible as topography poorly affects wave propagation at these long periods and the landslide seismic source can be approximated as a point source. In the near-field and at higher frequencies (> 1 Hz) the spatial extent of the source has to be taken into account and the influence of the topography on the recorded seismic signal should be quantified in order to extract information on the landslide properties and dynamics. The characteristic signature of distributed sources and varying topographies is studied as a function of frequency and recording distance.The time dependent spatial distribution of the forces applied to the ground by the landslide are obtained using granular flow numerical modeling on 3D topography. The generated seismic waves are simulated using the spectral element method. The simulated seismic signal is compared to observed seismic data from rockfalls at the Dolomieu Crater of Piton de la Fournaise (La Réunion).Favreau, P., Mangeney, A., Lucas, A., Crosta, G., and Bouchut, F. (2010). Numerical modeling of landquakes. Geophysical Research Letters, 37(15):1-5.

  10. A proton point source produced by laser interaction with cone-top-end target

    International Nuclear Information System (INIS)

    Yu, Jinqing; Jin, Xiaolin; Zhou, Weimin; Zhao, Zongqing; Yan, Yonghong; Li, Bin; Hong, Wei; Gu, Yuqiu

    2012-01-01

    In this paper, we propose a proton point source by the interaction of laser and cone-top-end target and investigate it by two-dimensional particle-in-cell (2D-PIC) simulations as the proton point sources are well known for higher spatial resolution of proton radiography. Our results show that the relativistic electrons are guided to the rear of the cone-top-end target by the electrostatic charge-separation field and self-generated magnetic field along the profile of the target. As a result, the peak magnitude of sheath field at the rear surface of cone-top-end target is higher compared to common cone target. We test this scheme by 2D-PIC simulation and find the result has a diameter of 0.79λ 0 , an average energy of 9.1 MeV and energy spread less than 35%.

  11. Simulation of ultrasonic surface waves with multi-Gaussian and point source beam models

    International Nuclear Information System (INIS)

    Zhao, Xinyu; Schmerr, Lester W. Jr.; Li, Xiongbing; Sedov, Alexander

    2014-01-01

    In the past decade, multi-Gaussian beam models have been developed to solve many complicated bulk wave propagation problems. However, to date those models have not been extended to simulate the generation of Rayleigh waves. Here we will combine Gaussian beams with an explicit high frequency expression for the Rayleigh wave Green function to produce a three-dimensional multi-Gaussian beam model for the fields radiated from an angle beam transducer mounted on a solid wedge. Simulation results obtained with this model are compared to those of a point source model. It is shown that the multi-Gaussian surface wave beam model agrees well with the point source model while being computationally much more efficient

  12. Search for neutrino point sources with an all-sky autocorrelation analysis in IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Turcati, Andrea; Bernhard, Anna; Coenders, Stefan [TU, Munich (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    The IceCube Neutrino Observatory is a cubic kilometre scale neutrino telescope located in the Antarctic ice. Its full-sky field of view gives unique opportunities to study the neutrino emission from the Galactic and extragalactic sky. Recently, IceCube found the first signal of astrophysical neutrinos with energies up to the PeV scale, but the origin of these particles still remains unresolved. Given the observed flux, the absence of observations of bright point-sources is explainable with the presence of numerous weak sources. This scenario can be tested using autocorrelation methods. We present here the sensitivities and discovery potentials of a two-point angular correlation analysis performed on seven years of IceCube data, taken between 2008 and 2015. The test is applied on the northern and southern skies separately, using the neutrino energy information to improve the effectiveness of the method.

  13. Prevention and Control of Agricultural Non-Point Source Pollutions in UK and Suggestions to China

    OpenAIRE

    Liu, Kun; Ren, Tianzhi; Wu, Wenliang; Meng, Fanquiao; Bellarby, Jessica; Smith, Laurence

    2016-01-01

    Currently, the world is facing challenges of maintaining food production growth while improving agricultural ecological environmental quality. The prevention and control of agricultural non-point source pollution, a key component of these challenges, is a systematic program which integrates many factors such as technology and its extension, relevant regulation and policies. In the project of UK-China Sustainable Agriculture Innovation Network, we undertook a comprehensive analysis of the prev...

  14. High angle grain boundaries as sources or sinks for point defects

    Energy Technology Data Exchange (ETDEWEB)

    Balluffi, R.W.

    1979-09-01

    A secondary grain boundary dislocation climb model for high angle grain boundaries as sources/sinks for point defects is described in the light of recent advances in our knowledge of grain boundary structure. Experimental results are reviewed and are then compared with the expected behavior of the proposed model. Reasonably good consistency is found at the level of our present understanding of the subject. However, several gaps in our present knowledge still exist, and these are identified and discussed briefly.

  15. Gamma Rays from the Inner Milky Way: Dark Matter or Point Sources?

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    Studies of data from the Fermi Gamma-Ray Space Telescope have revealed bright gamma-ray emission from the central regions of our galaxy, with a spatial and spectral profile consistent with annihilating dark matter. I will present a new model-independent analysis that suggests that rather than originating from dark matter, the GeV excess may arise from a surprising new population of as-yet-unresolved gamma-ray point sources in the heart of the Milky Way.

  16. CO2 point sources and subsurface storage capacities for CO2 in aquifers in Norway

    International Nuclear Information System (INIS)

    Boee, Reidulv; Magnus, Christian; Osmundsen, Per Terje; Rindstad, Bjoern Ivar

    2002-01-01

    The GESTCO project comprises a study of the distribution and coincidence of thermal CO 2 emission sources and location/quality of geological storage capacity in Europe. Four of the most promising types of geological storage are being studied. 1. Onshore/offshore saline aquifers with or without lateral seal. 2. Low entalpy geothermal reservoirs. 3. Deep methane-bearing coal beds and abandoned coal and salt mines. 4. Exhausted or near exhausted hydrocarbon structures. In this report we present an inventory of CO 2 point sources in Norway (1999) and the results of the work within Study Area C: Deep saline aquifers offshore/near shore Northern and Central Norway. Also offshore/near shore Southern Norway has been included while the Barents Sea is not described in any detail. The most detailed studies are on the Tilje and Aare Formations on the Troendelag Platform off Mid-Norway and on the Sognefjord, Fensfjord and Krossfjord Formations, southeast of the Troll Field off Western Norway. The Tilje Formation has been chosen as one of the cases to be studied in greater detail (numerical modelling) in the project. This report shows that offshore Norway, there are concentrations of large CO 2 point sources in the Haltenbanken, the Viking Graben/Tampen Spur area, the Southern Viking Graben and the central Trough, while onshore Norway there are concentrations of point sources in the Oslofjord/Porsgrund area, along the coast of western Norway and in the Troendelag. A number of aquifers with large theoretical CO 2 storage potential are pointed out in the North Sea, the Norwegian Sea and in the Southern Barents Sea. The storage capacity in the depth interval 0.8 - 4 km below sea level is estimated to be ca. 13 Gt (13000000000 tonnes) CO 2 in geological traps (outside hydrocarbon fields), while the storage capacity in aquifers not confined to traps is estimated to be at least 280 Gt CO 2 . (Author)

  17. Fast and Accurate Rat Head Motion Tracking With Point Sources for Awake Brain PET.

    Science.gov (United States)

    Miranda, Alan; Staelens, Steven; Stroobants, Sigrid; Verhaeghe, Jeroen

    2017-07-01

    To avoid the confounding effects of anesthesia and immobilization stress in rat brain positron emission tomography (PET), motion tracking-based unrestrained awake rat brain imaging is being developed. In this paper, we propose a fast and accurate rat headmotion tracking method based on small PET point sources. PET point sources (3-4) attached to the rat's head are tracked in image space using 15-32-ms time frames. Our point source tracking (PST) method was validated using a manually moved microDerenzo phantom that was simultaneously tracked with an optical tracker (OT) for comparison. The PST method was further validated in three awake [ 18 F]FDG rat brain scans. Compared with the OT, the PST-based correction at the same frame rate (31.2 Hz) reduced the reconstructed FWHM by 0.39-0.66 mm for the different tested rod sizes of the microDerenzo phantom. The FWHM could be further reduced by another 0.07-0.13 mm when increasing the PST frame rate (66.7 Hz). Regional brain [ 18 F]FDG uptake in the motion corrected scan was strongly correlated ( ) with that of the anesthetized reference scan for all three cases ( ). The proposed PST method allowed excellent and reproducible motion correction in awake in vivo experiments. In addition, there is no need of specialized tracking equipment or additional calibrations to be performed, the point sources are practically imperceptible to the rat, and PST is ideally suitable for small bore scanners, where optical tracking might be challenging.

  18. Temperature Effects of Point Sources, Riparian Shading, and Dam Operations on the Willamette River, Oregon

    Science.gov (United States)

    Rounds, Stewart A.

    2007-01-01

    Water temperature is an important factor influencing the migration, rearing, and spawning of several important fish species in rivers of the Pacific Northwest. To protect these fish populations and to fulfill its responsibilities under the Federal Clean Water Act, the Oregon Department of Environmental Quality set a water temperature Total Maximum Daily Load (TMDL) in 2006 for the Willamette River and the lower reaches of its largest tributaries in northwestern Oregon. As a result, the thermal discharges of the largest point sources of heat to the Willamette River now are limited at certain times of the year, riparian vegetation has been targeted for restoration, and upstream dams are recognized as important influences on downstream temperatures. Many of the prescribed point-source heat-load allocations are sufficiently restrictive that management agencies may need to expend considerable resources to meet those allocations. Trading heat allocations among point-source dischargers may be a more economical and efficient means of meeting the cumulative point-source temperature limits set by the TMDL. The cumulative nature of these limits, however, precludes simple one-to-one trades of heat from one point source to another; a more detailed spatial analysis is needed. In this investigation, the flow and temperature models that formed the basis of the Willamette temperature TMDL were used to determine a spatially indexed 'heating signature' for each of the modeled point sources, and those signatures then were combined into a user-friendly, spreadsheet-based screening tool. The Willamette River Point-Source Heat-Trading Tool allows the user to increase or decrease the heating signature of each source and thereby evaluate the effects of a wide range of potential point-source heat trades. The predictions of the Trading Tool were verified by running the Willamette flow and temperature models under four different trading scenarios, and the predictions typically were accurate

  19. Non-point Source Pollutants Loss of Planting Industry in the Yunnan Plateau Lake Basin, China

    Directory of Open Access Journals (Sweden)

    ZHAO Zu-jun

    2017-12-01

    Full Text Available Non-point source pollution of planting has become a major factor affecting the quality and safety of water environment in our country. In recent years, some studies show that the loss of nitrogen and phosphorus in agricultural chemical fertilizers has led to more serious non-point source pollution. By means of the loss coefficient method and spatial overlay analysis, the loss amount, loss of strength and its spatial distribution characteristics of total nitrogen, total phosphorus, ammonium nitrogen and nitrate nitrogen were analyzed in the Fuxian Lake, Xingyun Lake and Qilu Lake Basin in 2015. The results showed that:The loss of total nitrogen was the highest in the three basins, following by ammonium nitrogen, nitrate nitrogen and total phosphorus, which the loss of intensity range were 2.73~22.07, 0.003~3.52, 0.01~2.25 kg·hm-2 and 0.05~1.36 kg·hm-2, respectively. Total nitrogen and total phosphorus loss were mainly concentrated in the southwest of Qilu Lake, west and south of Xingyun Lake. Ammonium nitrogen and nitrate nitrogen loss mainly concentrated in the south of Qilu Lake, south and north of Xingyun Lake. The loss of nitrogen and phosphorus was mainly derived from cash crops and rice. Therefore, zoning, grading and phased prevention and control schemes were proposed, in order to provide scientific basis for controlling non-point source pollution in the study area.

  20. Source reduction for prevention of methylene chloride hazards: cases from four industrial sectors

    Directory of Open Access Journals (Sweden)

    Ellenbecker Michael J

    2003-07-01

    Full Text Available Abstract Background Source reduction, defined as chemical, equipment and process changes that intervene in an industrial process to eliminate or reduce hazards, has not figured as a front-line strategy for the protection of workers' health. Such initiatives are popular for environmental protection, but their feasibility and effectiveness as an industrial hygiene approach have not been well described. Methods We investigated four cases of source reduction as a hazard prevention strategy in Massachusetts companies that had used methylene chloride, an occupational carcinogen, for cleaning and adhesive thinning. Three cases were retrospective and one was prospective, where the researchers assisted with the source reduction process change. Data were collected using qualitative research methods, including in-depth interviews and site visits. Results Motivated by environmental restrictions, a new worker health standard, and opportunity for productivity improvements, three companies eliminated their use of methylene chloride by utilizing available technologies and drop-in substitutes. Aided by technical assistance from the investigators, a fourth case dramatically reduced its use of methylene chloride via process and chemistry changes. While the companies' evaluations of potential work environment impacts of substitutes were not extensive, and in two cases new potential hazards were introduced, the overall impact of the source reduction strategy was deemed beneficial, both from a worker health and a production standpoint. Conclusion The findings from these four cases suggest that source reduction should be considered potentially feasible and effective for reducing or eliminating the potential hazards of methylene chloride exposure. Especially when faced with a hazard that is both an environmental and worker health concern, companies may chose to change their processes rather than rely on local exhaust ventilation equipment or personal protective

  1. The Herschel Virgo Cluster Survey. XVII. SPIRE point-source catalogs and number counts

    Science.gov (United States)

    Pappalardo, Ciro; Bendo, George J.; Bianchi, Simone; Hunt, Leslie; Zibetti, Stefano; Corbelli, Edvige; di Serego Alighieri, Sperello; Grossi, Marco; Davies, Jonathan; Baes, Maarten; De Looze, Ilse; Fritz, Jacopo; Pohlen, Michael; Smith, Matthew W. L.; Verstappen, Joris; Boquien, Médéric; Boselli, Alessandro; Cortese, Luca; Hughes, Thomas; Viaene, Sebastien; Bizzocchi, Luca; Clemens, Marcel

    2015-01-01

    Aims: We present three independent catalogs of point-sources extracted from SPIRE images at 250, 350, and 500 μm, acquired with the Herschel Space Observatory as a part of the Herschel Virgo Cluster Survey (HeViCS). The catalogs have been cross-correlated to consistently extract the photometry at SPIRE wavelengths for each object. Methods: Sources have been detected using an iterative loop. The source positions are determined by estimating the likelihood to be a real source for each peak on the maps, according to the criterion defined in the sourceExtractorSussextractor task. The flux densities are estimated using the sourceExtractorTimeline, a timeline-based point source fitter that also determines the fitting procedure with the width of the Gaussian that best reproduces the source considered. Afterwards, each source is subtracted from the maps, removing a Gaussian function in every position with the full width half maximum equal to that estimated in sourceExtractorTimeline. This procedure improves the robustness of our algorithm in terms of source identification. We calculate the completeness and the flux accuracy by injecting artificial sources in the timeline and estimate the reliability of the catalog using a permutation method. Results: The HeViCS catalogs contain about 52 000, 42 200, and 18 700 sources selected at 250, 350, and 500 μm above 3σ and are ~75%, 62%, and 50% complete at flux densities of 20 mJy at 250, 350, 500 μm, respectively. We then measured source number counts at 250, 350, and 500 μm and compare them with previous data and semi-analytical models. We also cross-correlated the catalogs with the Sloan Digital Sky Survey to investigate the redshift distribution of the nearby sources. From this cross-correlation, we select ~2000 sources with reliable fluxes and a high signal-to-noise ratio, finding an average redshift z ~ 0.3 ± 0.22 and 0.25 (16-84 percentile). Conclusions: The number counts at 250, 350, and 500 μm show an increase in

  2. Normalized Point Source Sensitivity for Off-Axis Optical Performance Evaluation of the Thirty Meter Telescope

    Science.gov (United States)

    Seo, Byoung-Joon; Nissly, Carl; Troy, Mitchell; Angeli, George

    2010-01-01

    The Normalized Point Source Sensitivity (PSSN) has previously been defined and analyzed as an On-Axis seeing-limited telescope performance metric. In this paper, we expand the scope of the PSSN definition to include Off-Axis field of view (FoV) points and apply this generalized metric for performance evaluation of the Thirty Meter Telescope (TMT). We first propose various possible choices for the PSSN definition and select one as our baseline. We show that our baseline metric has useful properties including the multiplicative feature even when considering Off-Axis FoV points, which has proven to be useful for optimizing the telescope error budget. Various TMT optical errors are considered for the performance evaluation including segment alignment and phasing, segment surface figures, temperature, and gravity, whose On-Axis PSSN values have previously been published by our group.

  3. Temporal-spatial distribution of non-point source pollution in a drinking water source reservoir watershed based on SWAT

    Directory of Open Access Journals (Sweden)

    M. Wang

    2015-05-01

    Full Text Available The conservation of drinking water source reservoirs has a close relationship between regional economic development and people’s livelihood. Research on the non-point pollution characteristics in its watershed is crucial for reservoir security. Tang Pu Reservoir watershed was selected as the study area. The non-point pollution model of Tang Pu Reservoir was established based on the SWAT (Soil and Water Assessment Tool model. The model was adjusted to analyse the temporal-spatial distribution patterns of total nitrogen (TN and total phosphorus (TP. The results showed that the loss of TN and TP in the reservoir watershed were related to precipitation in flood season. And the annual changes showed an "M" shape. It was found that the contribution of loss of TN and TP accounted for 84.5% and 85.3% in high flow years, and for 70.3% and 69.7% in low flow years, respectively. The contributions in normal flow years were 62.9% and 63.3%, respectively. The TN and TP mainly arise from Wangtan town, Gulai town, and Wangyuan town, etc. In addition, it was found that the source of TN and TP showed consistency in space.

  4. A scanning point source for quality control of FOV uniformity in GC-PET imaging

    International Nuclear Information System (INIS)

    Bergmann, H.; Minear, G.; Dobrozemsky, G.; Nowotny, R.; Koenig, B.

    2002-01-01

    Aim: PET imaging with coincidence cameras (GC-PET) requires additional quality control procedures to check the function of coincidence circuitry and detector zoning. In particular, the uniformity response over the field of view needs special attention since it is known that coincidence counting mode may suffer from non-uniformity effects not present in single photon mode. Materials and methods: An inexpensive linear scanner with a stepper motor and a digital interface to a PC with software allowing versatile scanning modes was developed. The scanner is used with a source holder containing a Sodium-22 point source. While moving the source along the axis of rotation of the GC-PET system, a tomographic acquisition takes place. The scan covers the full axial field of view of the 2-D or 3-D scatter frame. Depending on the acquisition software, point source scanning takes place continuously while only one projection is acquired or is done in step-and-shoot mode with the number of positions equal to the number of gantry steps. Special software was developed to analyse the resulting list mode acquisition files and to produce an image of the recorded coincidence events of each head. Results: Uniformity images of coincidence events were obtained after further correction for systematic sensitivity variations caused by acquisition geometry. The resulting images are analysed visually and by calculating NEMA uniformity indices as for a planar flood field. The method has been applied successfully to two different brands of GC-PET capable gamma cameras. Conclusion: Uniformity of GC-PET can be tested quickly and accurately with a routine QC procedure, using a Sodium-22 scanning point source and an inexpensive mechanical scanning device. The method can be used for both 2-D and 3-D acquisition modes and fills an important gap in the quality control system for GC-PET

  5. Detection of Point Sources on Two-Dimensional Images Based on Peaks

    Directory of Open Access Journals (Sweden)

    R. B. Barreiro

    2005-09-01

    Full Text Available This paper considers the detection of point sources in two-dimensional astronomical images. The detection scheme we propose is based on peak statistics. We discuss the example of the detection of far galaxies in cosmic microwave background experiments throughout the paper, although the method we present is totally general and can be used in many other fields of data analysis. We consider sources with a Gaussian profile—that is, a fair approximation of the profile of a point source convolved with the detector beam in microwave experiments—on a background modeled by a homogeneous and isotropic Gaussian random field characterized by a scale-free power spectrum. Point sources are enhanced with respect to the background by means of linear filters. After filtering, we identify local maxima and apply our detection scheme, a Neyman-Pearson detector that defines our region of acceptance based on the a priori pdf of the sources and the ratio of number densities. We study the different performances of some linear filters that have been used in this context in the literature: the Mexican hat wavelet, the matched filter, and the scale-adaptive filter. We consider as well an extension to two dimensions of the biparametric scale-adaptive filter (BSAF. The BSAF depends on two parameters which are determined by maximizing the number density of real detections while fixing the number density of spurious detections. For our detection criterion the BSAF outperforms the other filters in the interesting case of white noise.

  6. Using mobile source emission reductions to offset stationary surce rule requirements

    International Nuclear Information System (INIS)

    Nazemi, M.A.; Beruldsen, K.J.

    1993-01-01

    A number of mobile source strategies have been evaluated that could potentially be used as an alternative means of compliance with existing stationary source regulations, at a lower cost. The evaluation was spurred by both public and private sector interest in identifying the lowest cost air pollution reduction strategies, and the realization that mobile sources are the predominate contributor to the air pollution problem in the South Coast Air Quality Basin. Strategies evaluated included removing older vehicles from the in-use population, use of alternative fuels, inspection and maintenance measures, application of remote sensing technology, exceeding AVR requirements, as well as a number of other strategies. Key implementation issues have been identified, so that the viability of each mobile source strategies could be assessed. These issues include: (1) quantification of emissions benefits, (2) determining whether the mobile source strategy would generate emission reductions surplus to existing and planned mobile source regulations, and (3) assessing the potential for enforceability. The results of evaluation indicate that there are a number of promising mobile source emission strategies that could provide quantifiable, surplus, and enforceable emission reductions

  7. Source apportionment of nitrogen and phosphorus from non-point source pollution in Nansi Lake Basin, China.

    Science.gov (United States)

    Zhang, Bao-Lei; Cui, Bo-Hao; Zhang, Shu-Min; Wu, Quan-Yuan; Yao, Lei

    2018-05-03

    Nitrogen (N) and phosphorus (P) from non-point source (NPS) pollution in Nansi Lake Basin greatly influenced the water quality of Nansi Lake, which is the determinant factor for the success of East Route of South-North Water Transfer Project in China. This research improved Johnes export coefficient model (ECM) by developing a method to determine the export coefficients of different land use types based on the hydrological and water quality data. Taking NPS total nitrogen (TN) and total phosphorus (TP) as the study objects, this study estimated the contributions of different pollution sources and analyzed their spatial distributions based on the improved ECM. The results underlined that the method for obtaining output coefficients of land use types using hydrology and water quality data is feasible and accurate, and is suitable for the study of NPS pollution at large-scale basins. The average output structure of NPS TN from land use, rural breeding and rural life is 33.6, 25.9, and 40.5%, and the NPS TP is 31.6, 43.7, and 24.7%, respectively. Especially, dry land was the main land use source for both NPS TN and TP pollution, with the contributed proportions of 81.3 and 81.8% respectively. The counties of Zaozhuang, Tengzhou, Caoxian, Yuncheng, and Shanxian had higher contribution rates and the counties of Dingtao, Juancheng, and Caoxian had the higher load intensities for both NPS TN and TP pollution. The results of this study allowed for an improvement in the understanding of the pollution source contribution and enabled researchers and planners to focus on the most important sources and regions of NPS pollution.

  8. Agricultural non-point source pollution of glyphosate and AMPA at a catchment scale

    Science.gov (United States)

    Okada, Elena; Perez, Debora; De Geronimo, Eduardo; Aparicio, Virginia; Costa, Jose Luis

    2017-04-01

    Information on the actual input of pesticides into the environment is crucial for proper risk assessment and the design of risk reduction measures. The Crespo basin is found within the Balcarce County, located south-east of the Buenos Aires Province. The whole basin has an area of approximately 490 km2 and the river has a length of 65 km. This study focuses on the upper basin of the Crespo stream, covering an area of 226 km2 in which 94.7% of the land is under agricultural production representing a highly productive area, characteristic of the Austral Pampas region. In this study we evaluated the levels of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in soils; and the non-point source pollution of surface waters, stream sediments and groundwater, over a period of one year. Stream water samples were taken monthly using propylene bottles, from the center of the bridge. If present, sediment samples from the first 5 cm were collected using cylinder samplers. Groundwater samples were taken from windmills or electric pumps from different farms every two months. At the same time, composite soil samples (at 5 cm depth) were taken from an agricultural plot of each farm. Samples were analyzed for detection and quantification of glyphosate and AMPA using ultra-performance liquid chromatography coupled to a mass spectrometer (UPLC-MS/MS). The limit of detection (LD) in the soil samples was 0.5 μg Kg-1 and the limit of quantification (LQ) was 3 μg Kg-1, both for glyphosate and AMPA. In water samples the LD was 0.1 μg L-1 and the LQ was 0.5 μg L-1. The results showed that the herbicide dispersed into all the studied environmental compartments. Glyphosate and AMPA residues were detected in 34 and 54% of the stream water samples, respectively. Sediment samples had a higher detection frequency (>96%) than water samples, and there was no relationship between the presence in surface water with the detection in sediment samples. The presence in sediment samples

  9. IceCube point source searches using through-going muon tracks

    Energy Technology Data Exchange (ETDEWEB)

    Coenders, Stefan [TU Muenchen, Physik-Department, Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    The IceCube neutrino observatory located at the South Pole is the current largest neutrino telescope. Using through-going muon tracks, IceCube records approximately 130,000 events per year with reconstruction accuracy as low as 0.7 deg for energies of 10 TeV. Having analysed an integrated time-scale of 4 years, no sources of neutrinos have yet been observed. This talk deals with the current progress in point-source searches, adding another two years of data recorded in the years 2012 and 2013. In a combined search with starting events, sources of hard and soft spectra with- and with-out cut-offs are characterised.

  10. IceCube-Gen2 sensitivity improvement for steady neutrino point sources

    Energy Technology Data Exchange (ETDEWEB)

    Coenders, Stefan; Resconi, Elisa [TU Muenchen, Physik-Department, Excellence Cluster Universe, Boltzmannstr. 2, 85748 Garching (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    The observation of an astrophysical neutrino flux by high-energy events starting in IceCube strengthens the search for sources of astrophysical neutrinos. Identification of these sources requires good pointing at high statistics, mainly using muons created by charged-current muon neutrino interactions going through the IceCube detector. We report about preliminary studies of a possible high-energy extension IceCube-Gen2. Using a 6 times bigger detection volume, effective area as well as reconstruction accuracy will improve with respect to IceCube. Moreover, using (in-ice) active veto techniques will significantly improve the performance for Southern hemisphere events, where possible local candidate neutrino sources are located.

  11. Atmospheric observations for quantifying emissions of point-source synthetic greenhouse gases (CF4, NF3 and HFC-23)

    Science.gov (United States)

    Arnold, Tim; Manning, Alistair J.; Li, Shanlan; Kim, Jooil; Park, Sunyoung; Fraser, Paul J.; Mitrevski, Blagoj; Steele, L. Paul; Krummel, Paul B.; Mühle, Jens; Weiss, Ray F.

    2016-04-01

    The fluorinated species carbon tetrafluoride (CF4; PFC-14), nitrogen trifluoride (NF3) and trifluoromethane (CHF3; HFC-23) are potent greenhouse gases with 100-year global warming potentials of 6,630, 16,100 and 12,400, respectively. Unlike the majority of CFC-replacement compounds that are emitted from fugitive and mobile emission sources, these gases are largely emitted from large single point sources - semiconductor manufacturing facilities (all three), aluminium smelting plants (CF4) and chlorodifluoromethane factories (HFC-23). In this work we show the potential for atmospheric measurements to understand regional sources of these gases and to highlight emission 'hotspots'. We target our analysis on measurements from two Advanced Global Atmospheric Gases Experiment (AGAGE) long term monitoring sites that are particularly sensitive to regional emissions of these gases: Gosan on Jeju Island in the Republic of Korea and Cape Grim on Tasmania in Australia. These sites measure CF4, NF3 and HFC-23 alongside a suite of greenhouse and stratospheric ozone depleting gases every two hours using automated in situ gas-chromatography mass-spectrometry instrumentation. We couple each measurement to an analysis of air history using the regional atmospheric transport model NAME (Numerical Atmospheric dispersion Modelling Environment) driven by 3D meteorology from the Met Office's Unified Model, and use a Bayesian inverse method (InTEM - Inversion Technique for Emission Modelling) to calculate yearly emission changes over a decade (2005-2015) at high spatial resolution. At present these gases make a small contribution to global radiative forcing, however, given that their impact could rise significantly and that point sources of such gases can be mitigated, atmospheric monitoring could be an important tool for aiding emissions reduction policy.

  12. Lessons Learned from OMI Observations of Point Source SO2 Pollution

    Science.gov (United States)

    Krotkov, N.; Fioletov, V.; McLinden, Chris

    2011-01-01

    The Ozone Monitoring Instrument (OMI) on NASA Aura satellite makes global daily measurements of the total column of sulfur dioxide (SO2), a short-lived trace gas produced by fossil fuel combustion, smelting, and volcanoes. Although anthropogenic SO2 signals may not be detectable in a single OMI pixel, it is possible to see the source and determine its exact location by averaging a large number of individual measurements. We describe new techniques for spatial and temporal averaging that have been applied to the OMI SO2 data to determine the spatial distributions or "fingerprints" of SO2 burdens from top 100 pollution sources in North America. The technique requires averaging of several years of OMI daily measurements to observe SO2 pollution from typical anthropogenic sources. We found that the largest point sources of SO2 in the U.S. produce elevated SO2 values over a relatively small area - within 20-30 km radius. Therefore, one needs higher than OMI spatial resolution to monitor typical SO2 sources. TROPOMI instrument on the ESA Sentinel 5 precursor mission will have improved ground resolution (approximately 7 km at nadir), but is limited to once a day measurement. A pointable geostationary UVB spectrometer with variable spatial resolution and flexible sampling frequency could potentially achieve the goal of daily monitoring of SO2 point sources and resolve downwind plumes. This concept of taking the measurements at high frequency to enhance weak signals needs to be demonstrated with a GEOCAPE precursor mission before 2020, which will help formulating GEOCAPE measurement requirements.

  13. Tracking Poverty Reduction in Bhutan: Income Deprivation Alongside Deprivation in Other Sources of Happiness

    Science.gov (United States)

    Santos, Maria Emma

    2013-01-01

    This paper analyses poverty reduction in Bhutan between two points in time--2003 and 2007--from a multidimensional perspective. The measures estimated include consumption expenditure as well as other indicators which are directly (when possible) or indirectly associated to valuable functionings, namely, health, education, access to electricity,…

  14. Enhancement of precision and reduction of measuring points in tomographic reconstructions

    International Nuclear Information System (INIS)

    Lustfeld, H.; Hirschfeld, J.A.; Reissel, M.; Steffen, B.

    2011-01-01

    Accurate external measurements are required in tomographic problems to obtain a reasonable knowledge of the internal structures. Crucial is the distribution of the external measuring points. We suggest a procedure how to systematically optimize this distribution viz. to increase the precision (i.e. to shrink error bars) of the reconstruction by detecting the important and by eliminating the irrelevant measuring points. In a realistic numerical example we apply our scheme to magnetotomography of fuel cells. The result is striking: Starting from a smooth distribution of measuring points on a surface of a cuboid around the fuel cell, the number of measuring points can systematically be reduced by more than 90%. At the same time the precision increases by a factor of nearly 3.

  15. A general reduction method for one-loop N-point integrals

    International Nuclear Information System (INIS)

    Heinrich, G.; Binoth, T.

    2000-01-01

    In order to calculate cross sections with a large number of particles/jets in the final state at next-to-leading order, one has to reduce the occurring scalar and tensor one-loop integrals to a small set of known integrals. In massless theories, this reduction procedure is complicated by the presence of infrared divergences. Working in n = 4 - 2ε dimensions, it will be outlined how to achieve such a reduction for diagrams with an arbitrary number of external legs. As a result, any integral with more than four propagators and generic 4-dimensional external momenta can be reduced to box integrals

  16. Diffusion of dust particles from a point-source above ground level

    International Nuclear Information System (INIS)

    Hassan, M.H.A.; Eltayeb, I.A.

    1998-10-01

    A pollutant of small particles is emitted by a point source at a height h above ground level in an atmosphere in which a uni-directional wind speed, U, is prevailing. The pollutant is subjected to diffusion in all directions in the presence of advection and settling due to gravity. The equation governing the concentration of the pollutant is studied with the wind speed and the different components of diffusion tensor are proportional to the distance above ground level and the source has a uniform strength. Adopting a Cartesian system of coordinates in which the x-axis lies along the direction of the wind velocity, the z-axis is vertically upwards and the y-axis completes the right-hand triad, the solution for the concentration c(x,y,z) is obtained in closed form. The relative importance of the components of diffusion along the three axes is discussed. It is found that for any plane y=constant (=A), c(x,y,z) is concentrated along a curve of ''extensive pollution''. In the plane A=0, the concentration decreases along the line of extensive pollution as we move away from the source. However, for planes A≅0, the line of extensive pollution possesses a point of accumulation, which lies at a nonzero value of x. As we move away from the plane A=0, the point of accumulation moves laterally away from the plane x=0 and towards the plane z=0. The presence of the point of accumulation is entirely due to the presence of lateral diffusion. (author)

  17. Analysis of inconsistent source sampling in monte carlo weight-window variance reduction methods

    Directory of Open Access Journals (Sweden)

    David P. Griesheimer

    2017-09-01

    Full Text Available The application of Monte Carlo (MC to large-scale fixed-source problems has recently become possible with new hybrid methods that automate generation of parameters for variance reduction techniques. Two common variance reduction techniques, weight windows and source biasing, have been automated and popularized by the consistent adjoint-driven importance sampling (CADIS method. This method uses the adjoint solution from an inexpensive deterministic calculation to define a consistent set of weight windows and source particles for a subsequent MC calculation. One of the motivations for source consistency is to avoid the splitting or rouletting of particles at birth, which requires computational resources. However, it is not always possible or desirable to implement such consistency, which results in inconsistent source biasing. This paper develops an original framework that mathematically expresses the coupling of the weight window and source biasing techniques, allowing the authors to explore the impact of inconsistent source sampling on the variance of MC results. A numerical experiment supports this new framework and suggests that certain classes of problems may be relatively insensitive to inconsistent source sampling schemes with moderate levels of splitting and rouletting.

  18. Removal of oxides from alkali metal melts by reductive titration to electrical resistance-change end points

    Science.gov (United States)

    Tsang, Floris Y.

    1980-01-01

    Alkali metal oxides dissolved in alkali metal melts are reduced with soluble metals which are converted to insoluble oxides. The end points of the reduction is detected as an increase in electrical resistance across an alkali metal ion-conductive membrane interposed between the oxide-containing melt and a material capable of accepting the alkali metal ions from the membrane when a difference in electrical potential, of the appropriate polarity, is established across it. The resistance increase results from blocking of the membrane face by ions of the excess reductant metal, to which the membrane is essentially non-conductive.

  19. Flux and Mass Reduction Resulting from ZVIClay Remediation of a PCE DNAPL Source Zone

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Kjeldsen, Peter; Riis, C.

    2010-01-01

    of bentonite clay. The degradation of PCE in the treated source area and the development in the downstream flux of chlorinated compounds have been monitored in six sampling campaigns. A PCE half-life of 50 days and a reduction of the average concentration of PCE of more than 99% were found during the first...

  20. Using the Chandra Source-Finding Algorithm to Automatically Identify Solar X-ray Bright Points

    Science.gov (United States)

    Adams, Mitzi L.; Tennant, A.; Cirtain, J. M.

    2009-01-01

    This poster details a technique of bright point identification that is used to find sources in Chandra X-ray data. The algorithm, part of a program called LEXTRCT, searches for regions of a given size that are above a minimum signal to noise ratio. The algorithm allows selected pixels to be excluded from the source-finding, thus allowing exclusion of saturated pixels (from flares and/or active regions). For Chandra data the noise is determined by photon counting statistics, whereas solar telescopes typically integrate a flux. Thus the calculated signal-to-noise ratio is incorrect, but we find we can scale the number to get reasonable results. For example, Nakakubo and Hara (1998) find 297 bright points in a September 11, 1996 Yohkoh image; with judicious selection of signal-to-noise ratio, our algorithm finds 300 sources. To further assess the efficacy of the algorithm, we analyze a SOHO/EIT image (195 Angstroms) and compare results with those published in the literature (McIntosh and Gurman, 2005). Finally, we analyze three sets of data from Hinode, representing different parts of the decline to minimum of the solar cycle.

  1. Mercury exposure in terrestrial birds far downstream of an historical point source

    International Nuclear Information System (INIS)

    Jackson, Allyson K.; Evers, David C.; Folsom, Sarah B.; Condon, Anne M.; Diener, John; Goodrick, Lizzie F.; McGann, Andrew J.; Schmerfeld, John; Cristol, Daniel A.

    2011-01-01

    Mercury (Hg) is a persistent environmental contaminant found in many freshwater and marine ecosystems. Historical Hg contamination in rivers can impact the surrounding terrestrial ecosystem, but there is little known about how far downstream this contamination persists. In 2009, we sampled terrestrial forest songbirds at five floodplain sites up to 137 km downstream of an historical source of Hg along the South and South Fork Shenandoah Rivers (Virginia, USA). We found that blood total Hg concentrations remained elevated over the entire sampling area and there was little evidence of decline with distance. While it is well known that Hg is a pervasive and long-lasting aquatic contaminant, it has only been recently recognized that it also biomagnifies effectively in floodplain forest food webs. This study extends the area of concern for terrestrial habitats near contaminated rivers for more than 100 km downstream from a waterborne Hg point source. - Highlights: → We report blood mercury levels for terrestrial songbirds downstream of contamination. → Blood mercury levels remain elevated above reference for at least 137 km downstream. → Trends vary based on foraging guild and migration strategy. → Mercury affects terrestrial biota farther downstream than previously documented. - Blood mercury levels of forest songbirds remain elevated above reference levels for at least 137 km downstream of historical point source.

  2. Mercury exposure in terrestrial birds far downstream of an historical point source

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Allyson K., E-mail: allyson.jackson@briloon.org [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States); Evers, David C.; Folsom, Sarah B. [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); Condon, Anne M. [U.S. Fish and Wildlife Service, 6669 Short Lane, Gloucester, VA 23061 (United States); Diener, John; Goodrick, Lizzie F. [Biodiversity Research Institute, 19 Flaggy Meadow Road, Gorham, ME 04038 (United States); McGann, Andrew J. [Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States); Schmerfeld, John [U.S. Fish and Wildlife Service, 6669 Short Lane, Gloucester, VA 23061 (United States); Cristol, Daniel A. [Institute for Integrative Bird Behavior Studies, Department of Biology, College of William and Mary, PO Box 8795, Williamsburg, VA 23187 (United States)

    2011-12-15

    Mercury (Hg) is a persistent environmental contaminant found in many freshwater and marine ecosystems. Historical Hg contamination in rivers can impact the surrounding terrestrial ecosystem, but there is little known about how far downstream this contamination persists. In 2009, we sampled terrestrial forest songbirds at five floodplain sites up to 137 km downstream of an historical source of Hg along the South and South Fork Shenandoah Rivers (Virginia, USA). We found that blood total Hg concentrations remained elevated over the entire sampling area and there was little evidence of decline with distance. While it is well known that Hg is a pervasive and long-lasting aquatic contaminant, it has only been recently recognized that it also biomagnifies effectively in floodplain forest food webs. This study extends the area of concern for terrestrial habitats near contaminated rivers for more than 100 km downstream from a waterborne Hg point source. - Highlights: > We report blood mercury levels for terrestrial songbirds downstream of contamination. > Blood mercury levels remain elevated above reference for at least 137 km downstream. > Trends vary based on foraging guild and migration strategy. > Mercury affects terrestrial biota farther downstream than previously documented. - Blood mercury levels of forest songbirds remain elevated above reference levels for at least 137 km downstream of historical point source.

  3. Implementation of VOC source reduction practices in a manufactured house and in school classrooms

    International Nuclear Information System (INIS)

    Hodgson, A.T.; Apte, M.G.; Shendell, D.G.; Beal, D.; McIlvaine, J.E.R.

    2002-01-01

    Detailed studies of a new manufactured house and four new industrialized relocatable school classrooms were conducted to determine the emission sources of formaldehyde and other VOCs and to identify and implement source reduction practices. Procedures were developed to generate VOC emission factors that allowed reasonably accurate predictions of indoor air VOC concentrations. Based on the identified sources of formaldehyde and other aldehydes, practices were developed to reduce the concentrations of these compounds in new house construction. An alternate ceiling panel reduced formaldehyde concentrations in the classrooms. Overall, the classrooms had relatively low VOC concentrations

  4. Public risk-reduction measures: cost-effectiveness from a global point-of-view

    International Nuclear Information System (INIS)

    Oliveira, L.F.S. de; Motta Barros, E.B. da; Fleming, P.V.; Rosa, L.P.

    1985-05-01

    A review of systemic or global approach to cost-effectiveness analysis of risk-reduction measures is presented, and its advantages and limitations are discussed. The method is applied for problem of the cost-effectiveness of increasing the Angra 3 reactor containment wall thickness from 60cm to 180cm thick, in case of a direct commercial aircraft crash on it. (Author) [pt

  5. Reduction method for one-loop tensor 5- and 6-point integrals revisited

    International Nuclear Information System (INIS)

    Diakonidis, Theodoros

    2009-01-01

    A complete analytical reduction of general one-loop Feynman integrals with five legs for tensors up to rank R=3 and six legs for tensors up to rank 4 is reviewed. An elegant formalism with extensive use of signed minors was developed for the cancellation of leading inverse Gram determinants. The resulting compact formulae allow both for a study of analytical properties and for efficient numerical programming. Here some special numerical examples are presented. (orig.)

  6. Reduction method for one-loop tensor 5- and 6-point integrals revisited

    Energy Technology Data Exchange (ETDEWEB)

    Diakonidis, Theodoros [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2009-01-15

    A complete analytical reduction of general one-loop Feynman integrals with five legs for tensors up to rank R=3 and six legs for tensors up to rank 4 is reviewed. An elegant formalism with extensive use of signed minors was developed for the cancellation of leading inverse Gram determinants. The resulting compact formulae allow both for a study of analytical properties and for efficient numerical programming. Here some special numerical examples are presented. (orig.)

  7. Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

    Directory of Open Access Journals (Sweden)

    T. Marpaung

    2012-08-01

    Full Text Available In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS, due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed source. The reuse and recycle policy for spent and disused sealed sources are not already specified yet. The reuse of spent sealed sources can be applied only for the sources which had been used in the medical field for radiotherapy, namely the reuse of a teletherapy Co-60 source in a calibration facility. The recycle of a spent sealed source can be performed for radioactive sources with relatively high activities and long half-lives; however, the recycling activity may only be performed by the manufacturer. To avoid legal conflicts, in the amendment to the Government Regulation No.27 Year 2002 on Management of Radioactive Waste, there will be a recommendation for a new scheme in the management of radioactive waste to facilitate the application of the principles of reduce, reuse, and recycle

  8. Reduction of Radioactive Waste Through the Reuse and Recycle Policy of the Sealed Radioactive Sources Management

    International Nuclear Information System (INIS)

    Marpaung, T.

    2012-01-01

    In the past few years, the utilization of sealed source for medical, industrial and research purposes has shown an accelerating increase. This situation will lead to increases in the amount of sealed radioactive. During its use, a sealed radioactive waste will eventually become either a spent sealed source or disused sealed radioactive source (DSRS), due to certain factors. The reduction of the amount of radioactive waste can be executed through the application of reuse and recycle of sealed source. The reuse and recycle policy for spent and disused sealed sources are not already specified yet. The reuse of spent sealed sources can be applied only for the sources which had been used in the medical field for radiotherapy, namely the reuse of a teletherapy Co-60 source in a calibration facility. The recycle of a spent sealed source can be performed for radioactive sources with relatively high activities and long half-lives; however, the recycling activity may only be performed by the manufacturer. To avoid legal conflicts, in the amendment to the Government Regulation No.27 Year 2002 on Management of Radioactive Waste, there will be a recommendation for a new scheme in the management of radioactive waste to facilitate the application of the principles of reduce, reuse, and recycle (author)

  9. Kernel integration scatter model for parallel beam gamma camera and SPECT point source response

    International Nuclear Information System (INIS)

    Marinkovic, P.M.

    2001-01-01

    Scatter correction is a prerequisite for quantitative single photon emission computed tomography (SPECT). In this paper a kernel integration scatter Scatter correction is a prerequisite for quantitative SPECT. In this paper a kernel integration scatter model for parallel beam gamma camera and SPECT point source response based on Klein-Nishina formula is proposed. This method models primary photon distribution as well as first Compton scattering. It also includes a correction for multiple scattering by applying a point isotropic single medium buildup factor for the path segment between the point of scatter an the point of detection. Gamma ray attenuation in the object of imaging, based on known μ-map distribution, is considered too. Intrinsic spatial resolution of the camera is approximated by a simple Gaussian function. Collimator is modeled simply using acceptance angles derived from the physical dimensions of the collimator. Any gamma rays satisfying this angle were passed through the collimator to the crystal. Septal penetration and scatter in the collimator were not included in the model. The method was validated by comparison with Monte Carlo MCNP-4a numerical phantom simulation and excellent results were obtained. The physical phantom experiments, to confirm this method, are planed to be done. (author)

  10. Strategies for lidar characterization of particulates from point and area sources

    Science.gov (United States)

    Wojcik, Michael D.; Moore, Kori D.; Martin, Randal S.; Hatfield, Jerry

    2010-10-01

    Use of ground based remote sensing technologies such as scanning lidar systems (light detection and ranging) has gained traction in characterizing ambient aerosols due to some key advantages such as wide area of regard (10 km2), fast response time, high spatial resolution (University, in conjunction with the USDA-ARS, has developed a three-wavelength scanning lidar system called Aglite that has been successfully deployed to characterize particle motion, concentration, and size distribution at both point and diffuse area sources in agricultural and industrial settings. A suite of massbased and size distribution point sensors are used to locally calibrate the lidar. Generating meaningful particle size distribution, mass concentration, and emission rate results based on lidar data is dependent on strategic onsite deployment of these point sensors with successful local meteorological measurements. Deployment strategies learned from field use of this entire measurement system over five years include the characterization of local meteorology and its predictability prior to deployment, the placement of point sensors to prevent contamination and overloading, the positioning of the lidar and beam plane to avoid hard target interferences, and the usefulness of photographic and written observational data.

  11. A systematic analysis of the Braitenberg vehicle 2b for point-like stimulus sources

    International Nuclear Information System (INIS)

    Rañó, Iñaki

    2012-01-01

    Braitenberg vehicles have been used experimentally for decades in robotics with limited empirical understanding. This paper presents the first mathematical model of the vehicle 2b, displaying so-called aggression behaviour, and analyses the possible trajectories for point-like smooth stimulus sources. This sensory-motor steering control mechanism is used to implement biologically grounded target approach, target-seeking or obstacle-avoidance behaviour. However, the analysis of the resulting model reveals that complex and unexpected trajectories can result even for point-like stimuli. We also prove how the implementation of the controller and the vehicle morphology interact to affect the behaviour of the vehicle. This work provides a better understanding of Braitenberg vehicle 2b, explains experimental results and paves the way for a formally grounded application on robotics as well as for a new way of understanding target seeking in biology. (paper)

  12. Assessment of Groundwater Susceptibility to Non-Point Source Contaminants Using Three-Dimensional Transient Indexes.

    Science.gov (United States)

    Zhang, Yong; Weissmann, Gary S; Fogg, Graham E; Lu, Bingqing; Sun, HongGuang; Zheng, Chunmiao

    2018-06-05

    Groundwater susceptibility to non-point source contamination is typically quantified by stable indexes, while groundwater quality evolution (or deterioration globally) can be a long-term process that may last for decades and exhibit strong temporal variations. This study proposes a three-dimensional (3- d ), transient index map built upon physical models to characterize the complete temporal evolution of deep aquifer susceptibility. For illustration purposes, the previous travel time probability density (BTTPD) approach is extended to assess the 3- d deep groundwater susceptibility to non-point source contamination within a sequence stratigraphic framework observed in the Kings River fluvial fan (KRFF) aquifer. The BTTPD, which represents complete age distributions underlying a single groundwater sample in a regional-scale aquifer, is used as a quantitative, transient measure of aquifer susceptibility. The resultant 3- d imaging of susceptibility using the simulated BTTPDs in KRFF reveals the strong influence of regional-scale heterogeneity on susceptibility. The regional-scale incised-valley fill deposits increase the susceptibility of aquifers by enhancing rapid downward solute movement and displaying relatively narrow and young age distributions. In contrast, the regional-scale sequence-boundary paleosols within the open-fan deposits "protect" deep aquifers by slowing downward solute movement and displaying a relatively broad and old age distribution. Further comparison of the simulated susceptibility index maps to known contaminant distributions shows that these maps are generally consistent with the high concentration and quick evolution of 1,2-dibromo-3-chloropropane (DBCP) in groundwater around the incised-valley fill since the 1970s'. This application demonstrates that the BTTPDs can be used as quantitative and transient measures of deep aquifer susceptibility to non-point source contamination.

  13. The Atacama Cosmology Telescope: Development and preliminary results of point source observations

    Science.gov (United States)

    Fisher, Ryan P.

    2009-06-01

    The Atacama Cosmology Telescope (ACT) is a six meter diameter telescope designed to measure the millimeter sky with arcminute angular resolution. The instrument is currently conducting its third season of observations from Cerro Toco in the Chilean Andes. The primary science goal of the experiment is to expand our understanding of cosmology by mapping the temperature fluctuations of the Cosmic Microwave Background (CMB) at angular scales corresponding to multipoles up to [cursive l] ~ 10000. The primary receiver for current ACT observations is the Millimeter Bolometer Array Camera (MBAC). The instrument is specially designed to observe simultaneously at 148 GHz, 218 GHz and 277 GHz. To accomplish this, the camera has three separate detector arrays, each containing approximately 1000 detectors. After discussing the ACT experiment in detail, a discussion of the development and testing of the cold readout electronics for the MBAC is presented. Currently, the ACT collaboration is in the process of generating maps of the microwave sky using our first and second season observations. The analysis used to generate these maps requires careful data calibration to produce maps of the arcminute scale CMB temperature fluctuations. Tests and applications of several elements of the ACT calibrations are presented in the context of the second season observations. Scientific exploration has already begun on preliminary maps made using these calibrations. The final portion of this thesis is dedicated to discussing the point sources observed by the ACT. A discussion of the techniques used for point source detection and photometry is followed by a presentation of our current measurements of point source spectral indices.

  14. Point-Source Contributions to the Water Quality of an Urban Stream

    Science.gov (United States)

    Little, S. F. B.; Young, M.; Lowry, C.

    2014-12-01

    Scajaquada Creek, which runs through the heart of the city of Buffalo, is a prime example of the ways in which human intervention and local geomorphology can impact water quality and urban hydrology. Beginning in the 1920's, the Creek has been partially channelized and connected to Buffalo's combined sewer system (CSS). At Forest Lawn Cemetery, where this study takes place, Scajaquada Creek emerges from a 3.5-mile tunnel built to route stream flow under the city. Collocated with the tunnel outlet is a discharge point for Buffalo's CSS, combined sewer outlet (CSO) #53. It is at this point that runoff and sanitary sewage discharge regularly during rain events. Initially, this study endeavored to create a spatial and temporal picture for this portion of the Creek, monitoring such parameters as conductivity, dissolved oxygen, pH, temperature, and turbidity, in addition to measuring Escherichia coli (E. coli) concentrations. As expected, these factors responded directly to seasonality, local geomorphology, and distance from the point source (CSO #53), displaying a overall, linear response. However, the addition of nitrate and phosphate testing to the study revealed an entirely separate signal from that previously observed. Concentrations of these parameters did not respond to location in the same manner as E. coli. Instead of decreasing with distance from the CSO, a distinct periodicity was observed, correlating with a series of outflow pipes lining the stream banks. It is hypothesized that nitrate and phosphate occurring in this stretch of Scajaquada Creek originate not from the CSO, but from fertilizers used to maintain the lawns within the subwatershed. These results provide evidence of the complexity related to water quality issues in urban streams as a result of point- and nonpoint-source hydrologic inputs.

  15. Crowd-sourced BMS point matching and metadata maintenance with Babel

    DEFF Research Database (Denmark)

    Fürst, Jonathan; Chen, Kaifei; Katz, Randy H.

    2016-01-01

    Cyber-physical applications, deployed on top of Building Management Systems (BMS), promise energy saving and comfort improvement in non-residential buildings. Such applications are so far mainly deployed as research prototypes. The main roadblock to widespread adoption is the low quality of BMS...... systems. Such applications access sensors and actuators through BMS metadata in form of point labels. The naming of labels is however often inconsistent and incomplete. To tackle this problem, we introduce Babel, a crowd-sourced approach to the creation and maintenance of BMS metadata. In our system...

  16. UHE γ-rays from point sources based on GRAPES-I observations

    International Nuclear Information System (INIS)

    Gupta, S.K.; Sreekantan, B.V.; Srivatsan, R.; Tonwar, S.C.

    1993-01-01

    An experiment called GRAPES I (Gamma Ray Astronomy at PeV EnergieS) was set up in 1984 at Ooty in India, using 24 scintillation counters, to detect Extensive Air Showers (EAS) produced in the atmosphere by the primary cosmic radiation. The goal of the experiment has been to search for Ultra High Energy (UHE) γ-rays (E≥10 14 eV) from point sources in the sky. Here we discuss the results on X-ray binaries CYG X-3, HER X-1 and SCO X-1 obtained with GRAPES I experiment which covers the period 1984--87

  17. Point-source reconstruction with a sparse light-sensor array for optical TPC readout

    International Nuclear Information System (INIS)

    Rutter, G; Richards, M; Bennieston, A J; Ramachers, Y A

    2011-01-01

    A reconstruction technique for sparse array optical signal readout is introduced and applied to the generic challenge of large-area readout of a large number of point light sources. This challenge finds a prominent example in future, large volume neutrino detector studies based on liquid argon. It is concluded that the sparse array option may be ruled out for reasons of required number of channels when compared to a benchmark derived from charge readout on wire-planes. Smaller-scale detectors, however, could benefit from this technology.

  18. Magnox fuel inventories. Experiment and calculation using a point source model

    International Nuclear Information System (INIS)

    Nair, S.

    1978-08-01

    The results of calculations of Magnox fuel inventories using the point source code RICE and associated Magnox reactor data set have been compared with experimental measurements for the actinide isotopes 234 , 235 , 236 , 238 U, 238 , 239 , 240 , 241 , 242 Pu, 241 , 243 Am and 242 , 244 Cm and the fission product isotopes 142 , 143 , 144 , 145 , 146 , 150 Nd, 95 Zr, 134 , 137 Cs, 144 Ce and daughter 144 Pr produced in four samples of spent Magnox fuel spanning the burnup range 3000 to 9000 MWd/Te. The neutron emissions from a further two samples were also measured and compared with RICE predictions. The results of the comparison were such as to justify the use of the code RICE for providing source terms for environmental impact studies, for the isotopes considered in the present work. (author)

  19. The 1.4-2.7 micron spectrum of the point source at the galactic center

    Science.gov (United States)

    Treffers, R. R.; Fink, U.; Larson, H. P.; Gautier, T. N., III

    1976-01-01

    The spectrum of the 2-micron point source at the galactic center is presented over the range from 1.4 to 2.7 microns. The two-level-transition CO band heads are seen near 2.3 microns, confirming that the radiation from this source is due to a cool supergiant star. The heliocentric radial velocity is found to be - 173 (+ or -90) km/s and is consistent with the star being in orbit about a dense galactic nucleus. No evidence is found for Brackett-gamma emission, and no interstellar absorption features are seen. Upper limits for the column densities of interstellar H2, CH4, CO, and NH3 are derived.

  20. Development of uniform hazard response spectra for rock sites considering line and point sources of earthquakes

    International Nuclear Information System (INIS)

    Ghosh, A.K.; Kushwaha, H.S.

    2001-12-01

    Traditionally, the seismic design basis ground motion has been specified by normalised response spectral shapes and peak ground acceleration (PGA). The mean recurrence interval (MRI) used to computed for PGA only. It is shown that the MRI associated with such response spectra are not the same at all frequencies. The present work develops uniform hazard response spectra i.e. spectra having the same MRI at all frequencies for line and point sources of earthquakes by using a large number of strong motion accelerograms recorded on rock sites. Sensitivity of the number of the results to the changes in various parameters has also been presented. This work is an extension of an earlier work for aerial sources of earthquakes. These results will help to determine the seismic hazard at a given site and the associated uncertainities. (author)

  1. Correction of head movements in positron emission tomography using point source tracking system: a simulation study.

    Science.gov (United States)

    Nazarparvar, Babak; Shamsaei, Mojtaba; Rajabi, Hossein

    2012-01-01

    The motion of the head during brain positron emission tomography (PET) acquisitions has been identified as a source of artifact in the reconstructed image. In this study, a method is described to develop an image-based motion correction technique for correcting the post-acquisition data without using external optical motion-tracking system such as POLARIS. In this technique, GATE has been used to simulate PET brain scan using point sources mounted around the head to accurately monitor the position of the head during the time frames. The measurement of head motion in each frame showed a transformation in the image frame matrix, resulting in a fully corrected data set. Using different kinds of phantoms and motions, the accuracy of the correction method is tested and its applicability to experimental studies is demonstrated as well.

  2. A method for untriggered time-dependent searches for multiple flares from neutrino point sources

    International Nuclear Information System (INIS)

    Gora, D.; Bernardini, E.; Cruz Silva, A.H.

    2011-04-01

    A method for a time-dependent search for flaring astrophysical sources which can be potentially detected by large neutrino experiments is presented. The method uses a time-clustering algorithm combined with an unbinned likelihood procedure. By including in the likelihood function a signal term which describes the contribution of many small clusters of signal-like events, this method provides an effective way for looking for weak neutrino flares over different time-scales. The method is sensitive to an overall excess of events distributed over several flares which are not individually detectable. For standard cases (one flare) the discovery potential of the method is worse than a standard time-dependent point source analysis with unknown duration of the flare by a factor depending on the signal-to-background level. However, for flares sufficiently shorter than the total observation period, the method is more sensitive than a time-integrated analysis. (orig.)

  3. The acoustic field of a point source in a uniform boundary layer over an impedance plane

    Science.gov (United States)

    Zorumski, W. E.; Willshire, W. L., Jr.

    1986-01-01

    The acoustic field of a point source in a boundary layer above an impedance plane is investigated anatytically using Obukhov quasi-potential functions, extending the normal-mode theory of Chunchuzov (1984) to account for the effects of finite ground-plane impedance and source height. The solution is found to be asymptotic to the surface-wave term studies by Wenzel (1974) in the limit of vanishing wind speed, suggesting that normal-mode theory can be used to model the effects of an atmospheric boundary layer on infrasonic sound radiation. Model predictions are derived for noise-generation data obtained by Willshire (1985) at the Medicine Bow wind-turbine facility. Long-range downwind propagation is found to behave as a cylindrical wave, with attention proportional to the wind speed, the boundary-layer displacement thickness, the real part of the ground admittance, and the square of the frequency.

  4. Dynamic Control of Particle Deposition in Evaporating Droplets by an External Point Source of Vapor.

    Science.gov (United States)

    Malinowski, Robert; Volpe, Giovanni; Parkin, Ivan P; Volpe, Giorgio

    2018-02-01

    The deposition of particles on a surface by an evaporating sessile droplet is important for phenomena as diverse as printing, thin-film deposition, and self-assembly. The shape of the final deposit depends on the flows within the droplet during evaporation. These flows are typically determined at the onset of the process by the intrinsic physical, chemical, and geometrical properties of the droplet and its environment. Here, we demonstrate deterministic emergence and real-time control of Marangoni flows within the evaporating droplet by an external point source of vapor. By varying the source location, we can modulate these flows in space and time to pattern colloids on surfaces in a controllable manner.

  5. A method for untriggered time-dependent searches for multiple flares from neutrino point sources

    Energy Technology Data Exchange (ETDEWEB)

    Gora, D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Institute of Nuclear Physics PAN, Cracow (Poland); Bernardini, E.; Cruz Silva, A.H. [Institute of Nuclear Physics PAN, Cracow (Poland)

    2011-04-15

    A method for a time-dependent search for flaring astrophysical sources which can be potentially detected by large neutrino experiments is presented. The method uses a time-clustering algorithm combined with an unbinned likelihood procedure. By including in the likelihood function a signal term which describes the contribution of many small clusters of signal-like events, this method provides an effective way for looking for weak neutrino flares over different time-scales. The method is sensitive to an overall excess of events distributed over several flares which are not individually detectable. For standard cases (one flare) the discovery potential of the method is worse than a standard time-dependent point source analysis with unknown duration of the flare by a factor depending on the signal-to-background level. However, for flares sufficiently shorter than the total observation period, the method is more sensitive than a time-integrated analysis. (orig.)

  6. Chronic pelvic pain syndrome: reduction of medication use after pelvic floor physical therapy with an internal myofascial trigger point wand.

    Science.gov (United States)

    Anderson, Rodney U; Harvey, Richard H; Wise, David; Nevin Smith, J; Nathanson, Brian H; Sawyer, Tim

    2015-03-01

    This study documents the voluntary reduction in medication use in patients with refractory chronic pelvic pain syndrome utilizing a protocol of pelvic floor myofascial trigger point release with an FDA approved internal trigger point wand and paradoxical relaxation therapy. Self-referred patients were enrolled in a 6-day training clinic from October, 2008 to May, 2011 and followed the protocol for 6 months. Medication usage and symptom scores on a 1-10 scale (10 = most severe) were collected at baseline, and 1 and 6 months. All changes in medication use were at the patient's discretion. Changes in medication use were assessed by McNemar's test in both complete case and modified intention to treat (mITT) analyses. 374 out of 396 patients met inclusion criteria; 79.7 % were male, median age of 43 years and median symptom duration of 5 years. In the complete case analysis, the percent of patients using medications at baseline was 63.6 %. After 6 months of treatment the percentage was 40.1 %, a 36.9 % reduction (p < 0.001). In the mITT analysis, there was a 22.7 % overall reduction from baseline (p < 0.001). Medication cessation at 6 months was significantly associated with a reduction in total symptoms (p = 0.03).

  7. Decreasing Computational Time for VBBinaryLensing by Point Source Approximation

    Science.gov (United States)

    Tirrell, Bethany M.; Visgaitis, Tiffany A.; Bozza, Valerio

    2018-01-01

    The gravitational lens of a binary system produces a magnification map that is more intricate than a single object lens. This map cannot be calculated analytically and one must rely on computational methods to resolve. There are generally two methods of computing the microlensed flux of a source. One is based on ray-shooting maps (Kayser, Refsdal, & Stabell 1986), while the other method is based on an application of Green’s theorem. This second method finds the area of an image by calculating a Riemann integral along the image contour. VBBinaryLensing is a C++ contour integration code developed by Valerio Bozza, which utilizes this method. The parameters at which the source object could be treated as a point source, or in other words, when the source is far enough from the caustic, was of interest to substantially decrease the computational time. The maximum and minimum values of the caustic curves produced, were examined to determine the boundaries for which this simplification could be made. The code was then run for a number of different maps, with separation values and accuracies ranging from 10-1 to 10-3, to test the theoretical model and determine a safe buffer for which minimal error could be made for the approximation. The determined buffer was 1.5+5q, with q being the mass ratio. The theoretical model and the calculated points worked for all combinations of the separation values and different accuracies except the map with accuracy and separation equal to 10-3 for y1 max. An alternative approach has to be found in order to accommodate a wider range of parameters.

  8. Point, surface and volumetric heat sources in the thermal modelling of selective laser melting

    Science.gov (United States)

    Yang, Yabin; Ayas, Can

    2017-10-01

    Selective laser melting (SLM) is a powder based additive manufacturing technique suitable for producing high precision metal parts. However, distortions and residual stresses within products arise during SLM because of the high temperature gradients created by the laser heating. Residual stresses limit the load resistance of the product and may even lead to fracture during the built process. It is therefore of paramount importance to predict the level of part distortion and residual stress as a function of SLM process parameters which requires a reliable thermal modelling of the SLM process. Consequently, a key question arises which is how to describe the laser source appropriately. Reasonable simplification of the laser representation is crucial for the computational efficiency of the thermal model of the SLM process. In this paper, first a semi-analytical thermal modelling approach is described. Subsequently, the laser heating is modelled using point, surface and volumetric sources, in order to compare the influence of different laser source geometries on the thermal history prediction of the thermal model. The present work provides guidelines on appropriate representation of the laser source in the thermal modelling of the SLM process.

  9. Seasonal and spatial variation of diffuse (non-point) source zinc pollution in a historically metal mined river catchment, UK

    Energy Technology Data Exchange (ETDEWEB)

    Gozzard, E., E-mail: emgo@ceh.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Mayes, W.M., E-mail: W.Mayes@hull.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Potter, H.A.B., E-mail: hugh.potter@environment-agency.gov.uk [Environment Agency England and Wales, c/o Institute for Research on Environment and Sustainability, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom); Jarvis, A.P., E-mail: a.p.jarvis@ncl.ac.uk [Hydrogeochemical Engineering Research and Outreach Group, School of Civil Engineering and Geosciences, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2011-10-15

    Quantifying diffuse sources of pollution is becoming increasingly important when characterising river catchments in entirety - a prerequisite for environmental management. This study examines both low and high flow events, as well as spatial variability, in order to assess point and diffuse components of zinc pollution within the River West Allen catchment, which lies within the northern England lead-zinc Orefield. Zinc levels in the river are elevated under all flow regimes, and are of environmental concern. Diffuse components are of little importance at low flow, with point source mine water discharges dominating instream zinc concentration and load. During higher river flows 90% of the instream zinc load is attributed to diffuse sources, where inputs from resuspension of metal-rich sediments, and groundwater influx are likely to be more dominant. Remediating point mine water discharges should significantly improve water quality at lower flows, but contribution from diffuse sources will continue to elevate zinc flux at higher flows. - Highlights: > Zinc concentrations breach EU quality thresholds under all river flow conditions. > Contributions from point sources dominate instream zinc dynamics in low flow. > Contributions from diffuse sources dominate instream zinc dynamics in high flow. > Important diffuse sources include river-bed sediment resuspension and groundwater influx. > Diffuse sources would still create significant instream pollution, even with point source treatment. - Diffuse zinc sources are an important source of instream contamination to mine-impacted rivers under varying flow conditions.

  10. Calibrate the aerial surveying instrument by the limited surface source and the single point source that replace the unlimited surface source

    International Nuclear Information System (INIS)

    Lu Cunheng

    1999-01-01

    It is described that the calculating formula and surveying result is found on the basis of the stacking principle of gamma ray and the feature of hexagonal surface source when the limited surface source replaces the unlimited surface source to calibrate the aerial survey instrument on the ground, and that it is found in the light of the exchanged principle of the gamma ray when the single point source replaces the unlimited surface source to calibrate aerial surveying instrument in the air. Meanwhile through the theoretical analysis, the receiving rate of the crystal bottom and side surfaces is calculated when aerial surveying instrument receives gamma ray. The mathematical expression of the gamma ray decaying following height according to the Jinge function regularity is got. According to this regularity, the absorbing coefficient that air absorbs the gamma ray and the detective efficiency coefficient of the crystal is calculated based on the ground and air measuring value of the bottom surface receiving count rate (derived from total receiving count rate of the bottom and side surface). Finally, according to the measuring value, it is proved that imitating the change of total receiving gamma ray exposure rate of the bottom and side surfaces with this regularity in a certain high area is feasible

  11. [Urban non-point source pollution control by runoff retention and filtration pilot system].

    Science.gov (United States)

    Bai, Yao; Zuo, Jian-E; Gan, Li-Li; Low, Thong Soon; Miao, Heng-Feng; Ruan, Wen-Quan; Huang, Xia

    2011-09-01

    A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.

  12. Current status of agricultural and rural non-point source Pollution assessment in China

    International Nuclear Information System (INIS)

    Ongley, Edwin D.; Zhang Xiaolan; Yu Tao

    2010-01-01

    Estimates of non-point source (NPS) contribution to total water pollution in China range up to 81% for nitrogen and to 93% for phosphorus. We believe these values are too high, reflecting (a) misuse of estimation techniques that were developed in America under very different conditions and (b) lack of specificity on what is included as NPS. We compare primary methods used for NPS estimation in China with their use in America. Two observations are especially notable: empirical research is limited and does not provide an adequate basis for calibrating models nor for deriving export coefficients; the Chinese agricultural situation is so different than that of the United States that empirical data produced in America, as a basis for applying estimation techniques to rural NPS in China, often do not apply. We propose a set of national research and policy initiatives for future NPS research in China. - Estimation techniques used in China for non-point source pollution are evaluated as a basis for recommending future policies and research in NPS studies in China.

  13. Industrial point source CO2 emission strength estimation with aircraft measurements and dispersion modelling.

    Science.gov (United States)

    Carotenuto, Federico; Gualtieri, Giovanni; Miglietta, Franco; Riccio, Angelo; Toscano, Piero; Wohlfahrt, Georg; Gioli, Beniamino

    2018-02-22

    CO 2 remains the greenhouse gas that contributes most to anthropogenic global warming, and the evaluation of its emissions is of major interest to both research and regulatory purposes. Emission inventories generally provide quite reliable estimates of CO 2 emissions. However, because of intrinsic uncertainties associated with these estimates, it is of great importance to validate emission inventories against independent estimates. This paper describes an integrated approach combining aircraft measurements and a puff dispersion modelling framework by considering a CO 2 industrial point source, located in Biganos, France. CO 2 density measurements were obtained by applying the mass balance method, while CO 2 emission estimates were derived by implementing the CALMET/CALPUFF model chain. For the latter, three meteorological initializations were used: (i) WRF-modelled outputs initialized by ECMWF reanalyses; (ii) WRF-modelled outputs initialized by CFSR reanalyses and (iii) local in situ observations. Governmental inventorial data were used as reference for all applications. The strengths and weaknesses of the different approaches and how they affect emission estimation uncertainty were investigated. The mass balance based on aircraft measurements was quite succesful in capturing the point source emission strength (at worst with a 16% bias), while the accuracy of the dispersion modelling, markedly when using ECMWF initialization through the WRF model, was only slightly lower (estimation with an 18% bias). The analysis will help in highlighting some methodological best practices that can be used as guidelines for future experiments.

  14. Reduction of Acid-Fast and Non-Acid-Fast Bacteria by Point of Use Coagulation-Flocculation-Disinfection

    Directory of Open Access Journals (Sweden)

    Lisa M. Casanova

    2015-11-01

    Full Text Available Point of use (POU household water treatment is increasingly being adopted as a solution for access to safe water. Non-tuberculous Mycobacteria (NTM are found in water, but there is little research on whether NTM survive POU treatment. Mycobacteria may be removed by multi-barrier treatment systems that combine processes such as coagulation, settling and disinfection. This work evaluated removal of a non-tuberculous Mycobacterium (Mycobaterium terrae and a Gram-negative non-acid-fast environmental bacterium (Aeromonas hydrophila by combined coagulation-flocculation disinfection POU treatment. Aeromonas hydrophila showed 7.7 log10 reduction in demand free buffer, 6.8 log10 in natural surface water, and 4 log10 reduction in fecally contaminated surface water. Turbidity after treatment was <1 NTU. There was almost no reduction in levels of viable M. terrae by coagulant-flocculant-disinfectant in natural water after 30 minutes. The lack of Mycobacteria reduction was similar for both combined coagulant-flocculant-disinfectant and hypochlorite alone. A POU coagulant-flocculant-disinfectant treatment effectively reduced A. hydrophila from natural surface waters but not Mycobacteria. These results reinforce previous findings that POU coagulation-flocculation-disinfection is effective against gram-negative enteric bacteria. POU treatment and safe storage interventions may need to take into account risks from viable NTM in treated stored water and consider alternative treatment processes to achieve NTM reductions.

  15. Research of noise emission sources in railway transport and effective ways of their reduction

    Directory of Open Access Journals (Sweden)

    Zvolenský Peter

    2017-01-01

    Full Text Available In the EU conditions attention is systematically paid to noise reduction on the railways. Because TSI rules systematically tighten limits for noise emissions from railway vehicles, noise research must be addressed by all Member States, as the main technical solutions for railway vehicles and construction technological aspects of railway operations can result in lower noise exposure of affected areas or objects. The paper focuses on theoretical investigation of sources and paths of sound propagation, possibilities of noise reduction both on vehicles and by infrastructure and experimental measurements of the situation in transport practice. Methodology for reducing railway noise around tracks has been presented, too.

  16. Using rare earth elements to trace wind-driven dispersion of sediments from a point source

    Science.gov (United States)

    Van Pelt, R. Scott; Barnes, Melanie C. W.; Strack, John E.

    2018-06-01

    The entrainment and movement of aeolian sediments is determined by the direction and intensity of erosive winds. Although erosive winds may blow from all directions, in most regions there is a predominant direction. Dust emission causes the removal preferentially of soil nutrients and contaminants which may be transported tens to even thousands of kilometers from the source and deposited into other ecosystems. It would be beneficial to understand spatially and temporally how the soil source may be degraded and depositional zones enriched. A stable chemical tracer not found in the soil but applied to the surface of all particles in the surface soil would facilitate this endeavor. This study examined whether solution-applied rare earth elements (REEs) could be used to trace aeolian sediment movement from a point source through space and time at the field scale. We applied erbium nitrate solution to a 5 m2 area in the center of a 100 m diameter field 7854 m2 on the Southern High Plains of Texas. The solution application resulted in a soil-borne concentration three orders of magnitude greater than natively found in the field soil. We installed BSNE sampler masts in circular configurations and collected the trapped sediment weekly. We found that REE-tagged sediment was blown into every sampler mast during the course of the study but that there was a predominant direction of transport during the spring. This preliminary investigation suggests that the REEs provide a viable and incisive technique to study spatial and temporal variation of aeolian sediment movement from specific sources to identifiable locations of deposition or locations through which the sediments were transported as horizontal mass flux and the relative contribution of the specific source to the total mass flux.

  17. Super-resolution for a point source better than λ/500 using positive refraction

    International Nuclear Information System (INIS)

    Miñano, Juan C; González, Juan C; Benítez, Pablo; Grabovickic, Dejan; Marqués, Ricardo; Delgado, Vicente; Freire, Manuel

    2011-01-01

    Leonhardt (2009 New J. Phys. 11 093040) demonstrated that the two-dimensional (2D) Maxwell fish eye (MFE) lens can focus perfectly 2D Helmholtz waves of arbitrary frequency; that is, it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a ‘perfect point drain’ located at the corresponding image point. Moreover, a prototype with λ/5 super-resolution property for one microwave frequency has been manufactured and tested (Ma et al 2010 arXiv:1007.2530v1; Ma et al 2010 New J. Phys. 13 033016). However, neither software simulations nor experimental measurements for a broad band of frequencies have yet been reported. Here, we present steady-state simulations with a non-perfect drain for a device equivalent to the MFE, called the spherical geodesic waveguide (SGW), which predicts up to λ/500 super-resolution close to discrete frequencies. Out of these frequencies, the SGW does not show super-resolution in the analysis carried out. (paper)

  18. Super-resolution for a point source better than λ/500 using positive refraction

    Science.gov (United States)

    Miñano, Juan C.; Marqués, Ricardo; González, Juan C.; Benítez, Pablo; Delgado, Vicente; Grabovickic, Dejan; Freire, Manuel

    2011-12-01

    Leonhardt (2009 New J. Phys. 11 093040) demonstrated that the two-dimensional (2D) Maxwell fish eye (MFE) lens can focus perfectly 2D Helmholtz waves of arbitrary frequency; that is, it can transport perfectly an outward (monopole) 2D Helmholtz wave field, generated by a point source, towards a ‘perfect point drain’ located at the corresponding image point. Moreover, a prototype with λ/5 super-resolution property for one microwave frequency has been manufactured and tested (Ma et al 2010 arXiv:1007.2530v1; Ma et al 2010 New J. Phys. 13 033016). However, neither software simulations nor experimental measurements for a broad band of frequencies have yet been reported. Here, we present steady-state simulations with a non-perfect drain for a device equivalent to the MFE, called the spherical geodesic waveguide (SGW), which predicts up to λ/500 super-resolution close to discrete frequencies. Out of these frequencies, the SGW does not show super-resolution in the analysis carried out.

  19. Method of local pointed function reduction of original shape in Fourier transformation

    International Nuclear Information System (INIS)

    Dosch, H.; Slavyanov, S.Yu.

    2002-01-01

    The method for analytical reduction of the original shape in the one-dimensional Fourier transformation by the fourier image modulus is proposed. The basic concept of the method consists in the presentation of the model shape in the form of the local peak functions sum. The eigenfunctions, generated by the linear differential equations with the polynomial coefficients, are selected as the latter ones. This provides for the possibility of managing the Fourier transformation without numerical integration. This reduces the reverse task to the nonlinear regression with a small number of the evaluated parameters and to the numerical or asymptotic study on the model peak functions - the eigenfunctions of the differential tasks and their fourier images [ru

  20. Reduction at the source of household wastes: why not trying the inciting tariffing?; La reduction a la source des dechets menagers: pourquoi ne pas essayer la tarification incitative?

    Energy Technology Data Exchange (ETDEWEB)

    Glachant, M.

    2002-11-01

    This article discusses how the existing financing tools of the household wastes management implemented in France can be changed to become inciting tools for the reduction of the volume of wastes at the source. It comprises 5 parts: the first part presents the present day way of financing of the public utility of household wastes in France and discusses its (very modest) inciting effect. In the next two parts the possible modalities to make it more inciting are discussed. These parts stresses on two questions: is it better to charge the upstream producers via contributions to chartered companies or to charge the downstream households via volume- or weight-proportional fees? How much should they pay? Then some experiences of inciting tariffing are briefly reviewed: the Duales German system of upstream charging and the US and Dutch downstream charging systems. (J.S.)

  1. A point-of-care chemistry test for reduction of turnaround and clinical decision time.

    Science.gov (United States)

    Lee, Eui Jung; Shin, Sang Do; Song, Kyoung Jun; Kim, Seong Chun; Cho, Jin Seong; Lee, Seung Chul; Park, Ju Ok; Cha, Won Chul

    2011-06-01

    Our study compared clinical decision time between patients managed with a point-of-care chemistry test (POCT) and patients managed with the traditional central laboratory test (CLT). This was a randomized controlled multicenter trial in the emergency departments (EDs) of 5 academic teaching hospitals. We randomly assigned patients to POCT or CLT stratified by the Emergency Severity Index. A POCT chemistry analyzer (Piccolo; Abaxis, Inc, Union City, Calif), which is able to test liver panel, renal panel, pancreas enzymes, lipid panel, electrolytes, and blood gases, was set up in each ED. Primary and secondary end point was turnaround time and door-to-clinical-decision time. The total 2323 patients were randomly assigned to the POCT group (n = 1167) or to the CLT group (n = 1156). All of the basic characteristics were similar in the 2 groups. The turnaround time (median, interquartile range [IQR]) of the POCT group was shorter than that of the CLT group (14, 12-19 versus 55, 45-69 minutes; P CLT group (46, 33-61 versus 86, 68-107 minutes; P CLT group (P CLT. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Emissions of perfluorinated alkylated substances (PFAS) from point sources--identification of relevant branches.

    Science.gov (United States)

    Clara, M; Scheffknecht, C; Scharf, S; Weiss, S; Gans, O

    2008-01-01

    Effluents of wastewater treatment plants are relevant point sources for the emission of hazardous xenobiotic substances to the aquatic environment. One group of substances, which recently entered scientific and political discussions, is the group of the perfluorinated alkylated substances (PFAS). The most studied compounds from this group are perfluorooctanoic acid (PFOA) and perfluorooctane sulphonate (PFOS), which are the most important degradation products of PFAS. These two substances are known to be persistent, bioaccumulative and toxic (PBT). In the present study, eleven PFAS were investigated in effluents of municipal wastewater treatment plants (WWTP) and in industrial wastewaters. PFOS and PFOA proved to be the dominant compounds in all sampled wastewaters. Concentrations of up to 340 ng/L of PFOS and up to 220 ng/L of PFOA were observed. Besides these two compounds, perfluorohexanoic acid (PFHxA) was also present in nearly all effluents and maximum concentrations of up to 280 ng/L were measured. Only N-ethylperfluorooctane sulphonamide (N-EtPFOSA) and its degradation/metabolisation product perfluorooctane sulphonamide (PFOSA) were either detected below the limit of quantification or were not even detected at all. Beside the effluents of the municipal WWTPs, nine industrial wastewaters from six different industrial branches were also investigated. Significantly, the highest emissions or PFOS were observed from metal industry whereas paper industry showed the highest PFOA emission. Several PFAS, especially perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), perfluorododecanoic acid (PFDoA) and PFOS are predominantly emitted from industrial sources, with concentrations being a factor of 10 higher than those observed in the municipal WWTP effluents. Perfluorodecane sulphonate (PFDS), N-Et-PFOSA and PFOSA were not detected in any of the sampled industrial point sources. (c) IWA Publishing 2008.

  3. Reduction of the environmental concentration of air pollutants by proper geometrical orientation of industrial line sources

    International Nuclear Information System (INIS)

    Tadmor, J.

    1980-01-01

    An account is given of an Israeli study of two line sources, one composed of 10 and the other of 20 individual sources. The height of release ranged from 15.7 to 39.6 m, with a uniform rate of release of a gaseous pollutant of 1 Ci/s for each source. Average pollutant concentration was plotted as a function of the rotation angle of the line sources. Reduction of pollutant concentration by a particular rotation of the line sources attained values of up to 50%. At certain rotation angles of the line sources, the environmental concentration was lower even as compared with a single high source. Results also depended on atmospheric conditions. It is suggested that considering the increase in cost of augmenting the height of release as a means of reducing the air pollutant concentration, determination of the optimum geometric orientation of the line sources should be considered as an economical means of improving environmental air quality. (U.K.)

  4. Reduction of sources of error and simplification of the Carbon-14 urea breath test

    International Nuclear Information System (INIS)

    Bellon, M.S.

    1997-01-01

    Full text: Carbon-14 urea breath testing is established in the diagnosis of H. pylori infection. The aim of this study was to investigate possible further simplification and identification of error sources in the 14 C urea kit extensively used at the Royal Adelaide Hospital. Thirty six patients with validated H. pylon status were tested with breath samples taken at 10,15, and 20 min. Using the single sample value at 15 min, there was no change in the diagnostic category. Reduction or errors in analysis depends on attention to the following details: Stability of absorption solution, (now > 2 months), compatibility of scintillation cocktail/absorption solution. (with particular regard to photoluminescence and chemiluminescence), reduction in chemical quenching (moisture reduction), understanding counting hardware and relevance, and appropriate response to deviation in quality assurance. With this experience, we are confident of the performance and reliability of the RAPID-14 urea breath test kit now available commercially

  5. Launching and controlling Gaussian beams from point sources via planar transformation media

    Science.gov (United States)

    Odabasi, Hayrettin; Sainath, Kamalesh; Teixeira, Fernando L.

    2018-02-01

    Based on operations prescribed under the paradigm of complex transformation optics (CTO) [F. Teixeira and W. Chew, J. Electromagn. Waves Appl. 13, 665 (1999), 10.1163/156939399X01104; F. L. Teixeira and W. C. Chew, Int. J. Numer. Model. 13, 441 (2000), 10.1002/1099-1204(200009/10)13:5%3C441::AID-JNM376%3E3.0.CO;2-J; H. Odabasi, F. L. Teixeira, and W. C. Chew, J. Opt. Soc. Am. B 28, 1317 (2011), 10.1364/JOSAB.28.001317; B.-I. Popa and S. A. Cummer, Phys. Rev. A 84, 063837 (2011), 10.1103/PhysRevA.84.063837], it was recently shown in [G. Castaldi, S. Savoia, V. Galdi, A. Alù, and N. Engheta, Phys. Rev. Lett. 110, 173901 (2013), 10.1103/PhysRevLett.110.173901] that a complex source point (CSP) can be mimicked by parity-time (PT ) transformation media. Such coordinate transformation has a mirror symmetry for the imaginary part, and results in a balanced loss/gain metamaterial slab. A CSP produces a Gaussian beam and, consequently, a point source placed at the center of such a metamaterial slab produces a Gaussian beam propagating away from the slab. Here, we extend the CTO analysis to nonsymmetric complex coordinate transformations as put forth in [S. Savoia, G. Castaldi, and V. Galdi, J. Opt. 18, 044027 (2016), 10.1088/2040-8978/18/4/044027] and verify that, by using simply a (homogeneous) doubly anisotropic gain-media metamaterial slab, one can still mimic a CSP and produce Gaussian beam. In addition, we show that a Gaussian-like beams can be produced by point sources placed outside the slab as well. By making use of the extra degrees of freedom (the real and imaginary parts of the coordinate transformation) provided by CTO, the near-zero requirement on the real part of the resulting constitutive parameters can be relaxed to facilitate potential realization of Gaussian-like beams. We illustrate how beam properties such as peak amplitude and waist location can be controlled by a proper choice of (complex-valued) CTO Jacobian elements. In particular, the beam waist

  6. Quantitative Analysis of VIIRS DNB Nightlight Point Source for Light Power Estimation and Stability Monitoring

    Directory of Open Access Journals (Sweden)

    Changyong Cao

    2014-12-01

    Full Text Available The high sensitivity and advanced onboard calibration on the Visible Infrared Imaging Radiometer Suite (VIIRS Day/Night Band (DNB enables accurate measurements of low light radiances which leads to enhanced quantitative applications at night. The finer spatial resolution of DNB also allows users to examine social economic activities at urban scales. Given the growing interest in the use of the DNB data, there is a pressing need for better understanding of the calibration stability and absolute accuracy of the DNB at low radiances. The low light calibration accuracy was previously estimated at a moderate 15% using extended sources while the long-term stability has yet to be characterized. There are also several science related questions to be answered, for example, how the Earth’s atmosphere and surface variability contribute to the stability of the DNB measured radiances; how to separate them from instrument calibration stability; whether or not SI (International System of Units traceable active light sources can be designed and installed at selected sites to monitor the calibration stability, radiometric and geolocation accuracy, and point spread functions of the DNB; furthermore, whether or not such active light sources can be used for detecting environmental changes, such as aerosols. This paper explores the quantitative analysis of nightlight point sources, such as those from fishing vessels, bridges, and cities, using fundamental radiometry and radiative transfer, which would be useful for a number of applications including search and rescue in severe weather events, as well as calibration/validation of the DNB. Time series of the bridge light data are used to assess the stability of the light measurements and the calibration of VIIRS DNB. It was found that the light radiant power computed from the VIIRS DNB data matched relatively well with independent assessments based on the in situ light installations, although estimates have to be

  7. Impacts by point and diffuse micropollutant sources on the stream water quality at catchment scale

    Science.gov (United States)

    Petersen, M. F.; Eriksson, E.; Binning, P. J.; Bjerg, P. L.

    2012-04-01

    The water quality of surface waters is threatened by multiple anthropogenic pollutants and the large variety of pollutants challenges the monitoring and assessment of the water quality. The aim of this study was to characterize and quantify both point and diffuse sources of micropollutants impacting the water quality of a stream at catchment scale. Grindsted stream in western Jutland, Denmark was used as a study site. The stream passes both urban and agricultural areas and is impacted by severe groundwater contamination in Grindsted city. Along a 12 km reach of Grindsted stream, the potential pollution sources were identified including a pharmaceutical factory site with a contaminated old drainage ditch, two waste deposits, a wastewater treatment plant, overflow structures, fish farms, industrial discharges and diffuse agricultural and urban sources. Six water samples were collected along the stream and analyzed for general water quality parameters, inorganic constituents, pesticides, sulfonamides, chlorinated solvents, BTEXs, and paracetamol and ibuprofen. The latter two groups were not detected. The general water quality showed typical conditions for a stream in western Jutland. Minor impacts by releases of organic matter and nutrients were found after the fish farms and the waste water treatment plant. Nickel was found at concentrations 5.8 - 8.8 μg/l. Nine pesticides and metabolites of both agricultural and urban use were detected along the stream; among these were the two most frequently detected and some rarely detected pesticides in Danish water courses. The concentrations were generally consistent with other findings in Danish streams and in the range 0.01 - 0.09 μg/l; except for metribuzin-diketo that showed high concentrations up to 0.74 μg/l. The groundwater contamination at the pharmaceutical factory site, the drainage ditch and the waste deposits is similar in composition containing among others sulfonamides and chlorinated solvents (including vinyl

  8. Search for point-like sources using the diffuse astrophysical muon-neutrino flux in IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Rene; Haack, Christian; Raedel, Leif; Schoenen, Sebastian; Schumacher, Lisa; Wiebusch, Christopher [III. Physikalisches Institut B, RWTH Aachen (Germany); Collaboration: IceCube-Collaboration

    2016-07-01

    IceCube, a cubic-kilometer sized neutrino detector at the geographic South Pole, has recently confirmed a flux of high-energy astrophysical neutrinos in the track-like muon channel. Although this muon-neutrino flux has now been observed with high significance, no point sources or source classes could be identified yet with these well pointing events. We present a search for point-like sources based on a six year sample of upgoing muon-neutrinos with very low background contamination. To improve the sensitivity, the standard likelihood approach has been modified to focus on the properties of the measured astrophysical muon-neutrino flux.

  9. Broadband integrated mid infrared light sources as enabling technology for point of care mid-infrared spectroscopy

    Science.gov (United States)

    2017-08-20

    AFRL-AFOSR-JP-TR-2017-0061 Broadband integrated mid-infrared light sources as enabling technology for point-of-care mid- infrared spectroscopy Alex...mid-infrared light sources as enabling technology for point-of-care mid-infrared spectroscopy 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER FA2386-16-1-4037...Broadband integrated mid-infrared light sources as enabling technology for point-of-care mid- infrared spectroscopy ” Date: 16th August 2017 Name

  10. Radial Basis Functional Model of Multi-Point Dieless Forming Process for Springback Reduction and Compensation

    Directory of Open Access Journals (Sweden)

    Misganaw Abebe

    2017-11-01

    Full Text Available Springback in multi-point dieless forming (MDF is a common problem because of the small deformation and blank holder free boundary condition. Numerical simulations are widely used in sheet metal forming to predict the springback. However, the computational time in using the numerical tools is time costly to find the optimal process parameters value. This study proposes radial basis function (RBF to replace the numerical simulation model by using statistical analyses that are based on a design of experiment (DOE. Punch holding time, blank thickness, and curvature radius are chosen as effective process parameters for determining the springback. The Latin hypercube DOE method facilitates statistical analyses and the extraction of a prediction model in the experimental process parameter domain. Finite element (FE simulation model is conducted in the ABAQUS commercial software to generate the springback responses of the training and testing samples. The genetic algorithm is applied to find the optimal value for reducing and compensating the induced springback for the different blank thicknesses using the developed RBF prediction model. Finally, the RBF numerical result is verified by comparing with the FE simulation result of the optimal process parameters and both results show that the springback is almost negligible from the target shape.

  11. Model reduction method using variable-separation for stochastic saddle point problems

    Science.gov (United States)

    Jiang, Lijian; Li, Qiuqi

    2018-02-01

    In this paper, we consider a variable-separation (VS) method to solve the stochastic saddle point (SSP) problems. The VS method is applied to obtain the solution in tensor product structure for stochastic partial differential equations (SPDEs) in a mixed formulation. The aim of such a technique is to construct a reduced basis approximation of the solution of the SSP problems. The VS method attempts to get a low rank separated representation of the solution for SSP in a systematic enrichment manner. No iteration is performed at each enrichment step. In order to satisfy the inf-sup condition in the mixed formulation, we enrich the separated terms for the primal system variable at each enrichment step. For the SSP problems by regularization or penalty, we propose a more efficient variable-separation (VS) method, i.e., the variable-separation by penalty method. This can avoid further enrichment of the separated terms in the original mixed formulation. The computation of the variable-separation method decomposes into offline phase and online phase. Sparse low rank tensor approximation method is used to significantly improve the online computation efficiency when the number of separated terms is large. For the applications of SSP problems, we present three numerical examples to illustrate the performance of the proposed methods.

  12. Simulation of agricultural non-point source pollution in Xichuan by using SWAT model

    Science.gov (United States)

    Xing, Linan; Zuo, Jiane; Liu, Fenglin; Zhang, Xiaohui; Cao, Qiguang

    2018-02-01

    This paper evaluated the applicability of using SWAT to access agricultural non-point source pollution in Xichuan area. In order to build the model, DEM, soil sort and land use map, climate monitoring data were collected as basic database. The SWAT model was calibrated and validated for the SWAT was carried out using streamflow, suspended solids, total phosphorus and total nitrogen records from 2009 to 2011. Errors, coefficient of determination and Nash-Sutcliffe coefficient were considered to evaluate the applicability. The coefficient of determination were 0.96, 0.66, 0.55 and 0.66 for streamflow, SS, TN, and TP, respectively. Nash-Sutcliffe coefficient were 0.93, 0.5, 0.52 and 0.63, respectively. The results all meet the requirements. It suggested that the SWAT model can simulate the study area.

  13. Exposure buildup factors for a cobalt-60 point isotropic source for single and two layer slabs

    International Nuclear Information System (INIS)

    Chakarova, R.

    1992-01-01

    Exposure buildup factors for point isotropic cobalt-60 sources are calculated by the Monte Carlo method with statistical errors ranging from 1.5 to 7% for 1-5 mean free paths (mfp) thick water and iron single slabs and for 1 and 2 mfp iron layers followed by water layers 1-5 mfp thick. The computations take into account Compton scattering. The Monte Carlo data for single slab geometries are approximated by Geometric Progression formula. Kalos's formula using the calculated single slab buildup factors may be applied to reproduce the data for two-layered slabs. The presented results and discussion may help when choosing the manner in which the radiation field gamma irradiation units will be described. (author)

  14. Large-Eddy Simulation of Chemically Reactive Pollutant Transport from a Point Source in Urban Area

    Science.gov (United States)

    Du, Tangzheng; Liu, Chun-Ho

    2013-04-01

    Most air pollutants are chemically reactive so using inert scalar as the tracer in pollutant dispersion modelling would often overlook their impact on urban inhabitants. In this study, large-eddy simulation (LES) is used to examine the plume dispersion of chemically reactive pollutants in a hypothetical atmospheric boundary layer (ABL) in neutral stratification. The irreversible chemistry mechanism of ozone (O3) titration is integrated into the LES model. Nitric oxide (NO) is emitted from an elevated point source in a rectangular spatial domain doped with O3. The LES results are compared well with the wind tunnel results available in literature. Afterwards, the LES model is applied to idealized two-dimensional (2D) street canyons of unity aspect ratio to study the behaviours of chemically reactive plume over idealized urban roughness. The relation among various time scales of reaction/turbulence and dimensionless number are analysed.

  15. Use of multiple water surface flow constructed wetlands for non-point source water pollution control.

    Science.gov (United States)

    Li, Dan; Zheng, Binghui; Liu, Yan; Chu, Zhaosheng; He, Yan; Huang, Minsheng

    2018-05-02

    Multiple free water surface flow constructed wetlands (multi-FWS CWs) are a variety of conventional water treatment plants for the interception of pollutants. This review encapsulated the characteristics and applications in the field of ecological non-point source water pollution control technology. The roles of in-series design and operation parameters (hydraulic residence time, hydraulic load rate, water depth and aspect ratio, composition of influent, and plant species) for performance intensification were also analyzed, which were crucial to achieve sustainable and effective contaminants removal, especially the retention of nutrient. The mechanism study of design and operation parameters for the removal of nitrogen and phosphorus was also highlighted. Conducive perspectives for further research on optimizing its design/operation parameters and advanced technologies of ecological restoration were illustrated to possibly interpret the functions of multi-FWS CWs.

  16. Risk-based prioritization of ground water threatening point sources at catchment and regional scales

    DEFF Research Database (Denmark)

    Overheu, Niels Døssing; Tuxen, Nina; Flyvbjerg, John

    2014-01-01

    framework has been developed to enable a systematic and transparent risk assessment and prioritization of contaminant point sources, considering the local, catchment, or regional scales (Danish EPA, 2011, 2012). The framework has been tested in several catchments in Denmark with different challenges...... and needs, and two of these are presented. Based on the lessons learned, the Danish EPA has prepared a handbook to guide the user through the steps in a risk-based prioritization (Danish EPA, 2012). It provides guidance on prioritization both in an administratively defined area such as a Danish Region...... of the results are presented using the case studies as examples. The methodology was developed by a broad industry group including the Danish EPA, the Danish Regions, the Danish Nature Agency, the Technical University of Denmark, and consultants — and the framework has been widely accepted by the professional...

  17. Modeling a point-source release of 1,1,1-trichloroethane using EPA's SCREEN model

    International Nuclear Information System (INIS)

    Henriques, W.D.; Dixon, K.R.

    1994-01-01

    Using data from the Environmental Protection Agency's Toxic Release Inventory 1988 (EPA TRI88), pollutant concentration estimates were modeled for a point source air release of 1,1,1-trichloroethane at the Savannah River Plant located in Aiken, South Carolina. Estimates were calculating using the EPA's SCREEN model utilizing typical meteorological conditions to determine maximum impact of the plume under different mixing conditions for locations within 100 meters of the stack. Input data for the SCREEN model were then manipulated to simulate the impact of the release under urban conditions (for the purpose of assessing future landuse considerations) and under flare release options to determine if these parameters lessen or increase the probability of human or wildlife exposure to significant concentrations. The results were then compared to EPA reference concentrations (RfC) in order to assess the size of the buffer around the stack which may potentially have levels that exceed this level of safety

  18. Improvement of correlation-based centroiding methods for point source Shack-Hartmann wavefront sensor

    Science.gov (United States)

    Li, Xuxu; Li, Xinyang; wang, Caixia

    2018-03-01

    This paper proposes an efficient approach to decrease the computational costs of correlation-based centroiding methods used for point source Shack-Hartmann wavefront sensors. Four typical similarity functions have been compared, i.e. the absolute difference function (ADF), ADF square (ADF2), square difference function (SDF), and cross-correlation function (CCF) using the Gaussian spot model. By combining them with fast search algorithms, such as three-step search (TSS), two-dimensional logarithmic search (TDL), cross search (CS), and orthogonal search (OS), computational costs can be reduced drastically without affecting the accuracy of centroid detection. Specifically, OS reduces calculation consumption by 90%. A comprehensive simulation indicates that CCF exhibits a better performance than other functions under various light-level conditions. Besides, the effectiveness of fast search algorithms has been verified.

  19. Preliminary limits on the flux of muon neutrinos from extraterrestrial point sources

    International Nuclear Information System (INIS)

    Bionta, R.M.; Blewitt, G.; Bratton, C.B.

    1985-01-01

    We present the arrival directions of 117 upward-going muon events collected with the IMB proton lifetime detector during 317 days of live detector operation. The rate of upward-going muons observed in our detector was found to be consistent with the rate expected from atmospheric neutrino production. The upper limit on the total flux of extraterrestrial neutrinos >1 GeV is 2 -sec. Using our data and a Monte Carlo simulation of high energy muon production in the earth surrounding the detector, we place limits on the flux of neutrinos from a point source in the Vela X-2 system of 2 -sec with E > 1 GeV. 6 refs., 5 figs

  20. The potentional of renewable energy sources for greenhouse gases emissions reduction in Macedonia

    Directory of Open Access Journals (Sweden)

    Dedinec Aleksandar

    2012-01-01

    Full Text Available As European Union (EU candidate country, Macedonia is in the process of adoption of the EU strategic energy policies, harmonization of the national legislation with the EU legislation and defining the respective national goals. In this regard, the government has recently adopted a National Strategy for Utilization of Renewable Energy Sources (RES, prepared by ICEIM-MANU. The main goal of this paper is to assess the potential for greenhouse gases (GHG emissions reduction by implementation of 21%-RES-scenarios from the Strategy. The corresponding emissions reduction is calculated against the baseline (reference scenario developed within the Second National Communication on Climate Change. Furthermore, all potential RES technologies are analyzed from economic aspect and combined in a form of emissions reduction cost curve, displaying the total marginal cost of the GHG emissions reduction by RES. Finally, on the bases of the environmental and economic effectiveness of the considered RES technologies, as well as taking into account the country specific barriers, the priority actions for GHG emissions reduction are identified.

  1. Carbon dioxide capture and separation techniques for advanced power generation point sources

    Energy Technology Data Exchange (ETDEWEB)

    Pennline, H.W.; Luebke, D.R.; Morsi, B.I.; Heintz, Y.J.; Jones, K.L.; Ilconich, J.B.

    2006-09-01

    The capture/separation step for carbon dioxide (CO2) from large-point sources is a critical one with respect to the technical feasibility and cost of the overall carbon sequestration scenario. For large-point sources, such as those found in power generation, the carbon dioxide capture techniques being investigated by the in-house research area of the National Energy Technology Laboratory possess the potential for improved efficiency and costs as compared to more conventional technologies. The investigated techniques can have wide applications, but the research has focused on capture/separation of carbon dioxide from flue gas (postcombustion from fossil fuel-fired combustors) and from fuel gas (precombustion, such as integrated gasification combined cycle – IGCC). With respect to fuel gas applications, novel concepts are being developed in wet scrubbing with physical absorption; chemical absorption with solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Fabrication techniques and mechanistic studies for hybrid membranes separating CO2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO2-philic silanes incorporated into an alumina support or ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. An overview of two novel techniques is presented along with a research progress status of each technology.

  2. Carbon Dioxide Capture and Separation Techniques for Gasification-based Power Generation Point Sources

    Energy Technology Data Exchange (ETDEWEB)

    Pennline, H.W.; Luebke, D.R.; Jones, K.L.; Morsi, B.I. (Univ. of Pittsburgh, PA); Heintz, Y.J. (Univ. of Pittsburgh, PA); Ilconich, J.B. (Parsons)

    2007-06-01

    The capture/separation step for carbon dioxide (CO2) from large-point sources is a critical one with respect to the technical feasibility and cost of the overall carbon sequestration scenario. For large-point sources, such as those found in power generation, the carbon dioxide capture techniques being investigated by the in-house research area of the National Energy Technology Laboratory possess the potential for improved efficiency and reduced costs as compared to more conventional technologies. The investigated techniques can have wide applications, but the research has focused on capture/separation of carbon dioxide from flue gas (post-combustion from fossil fuel-fired combustors) and from fuel gas (precombustion, such as integrated gasification combined cycle or IGCC). With respect to fuel gas applications, novel concepts are being developed in wet scrubbing with physical absorption; chemical absorption with solid sorbents; and separation by membranes. In one concept, a wet scrubbing technique is being investigated that uses a physical solvent process to remove CO2 from fuel gas of an IGCC system at elevated temperature and pressure. The need to define an ideal solvent has led to the study of the solubility and mass transfer properties of various solvents. Pertaining to another separation technology, fabrication techniques and mechanistic studies for membranes separating CO2 from the fuel gas produced by coal gasification are also being performed. Membranes that consist of CO2-philic ionic liquids encapsulated into a polymeric substrate have been investigated for permeability and selectivity. Finally, dry, regenerable processes based on sorbents are additional techniques for CO2 capture from fuel gas. An overview of these novel techniques is presented along with a research progress status of technologies related to membranes and physical solvents.

  3. Field-scale operation of methane biofiltration systems to mitigate point source methane emissions

    International Nuclear Information System (INIS)

    Hettiarachchi, Vijayamala C.; Hettiaratchi, Patrick J.; Mehrotra, Anil K.; Kumar, Sunil

    2011-01-01

    Methane biofiltration (MBF) is a novel low-cost technique for reducing low volume point source emissions of methane (CH 4 ). MBF uses a granular medium, such as soil or compost, to support the growth of methanotrophic bacteria responsible for converting CH 4 to carbon dioxide (CO 2 ) and water (H 2 O). A field research program was undertaken to evaluate the potential to treat low volume point source engineered CH 4 emissions using an MBF at a natural gas monitoring station. A new comprehensive three-dimensional numerical model was developed incorporating advection-diffusive flow of gas, biological reactions and heat and moisture flow. The one-dimensional version of this model was used as a guiding tool for designing and operating the MBF. The long-term monitoring results of the field MBF are also presented. The field MBF operated with no control of precipitation, evaporation, and temperature, provided more than 80% of CH 4 oxidation throughout spring, summer, and fall seasons. The numerical model was able to predict the CH 4 oxidation behavior of the field MBF with high accuracy. The numerical model simulations are presented for estimating CH 4 oxidation efficiencies under various operating conditions, including different filter bed depths and CH 4 flux rates. The field observations as well as numerical model simulations indicated that the long-term performance of MBFs is strongly dependent on environmental factors, such as ambient temperature and precipitation. - Highlights: → One-dimensional version of the model was used as a guiding tool for designing and operating the MBF. → Mathematical model predicted CH 4 oxidation behaviors of the field MBF with high accuracy i.e. (> 80 %). → Performance of MBF is dependent on ambient temperature and precipitation. - The developed numerical model simulations and field observations for estimating CH 4 oxidation efficiencies under various operating conditions indicate that the long-term performance of MBFs is strongly

  4. Genome Reduction in Psychromonas Species within the Gut of an Amphipod from the Ocean's Deepest Point.

    Science.gov (United States)

    Zhang, Weipeng; Tian, Ren-Mao; Sun, Jin; Bougouffa, Salim; Ding, Wei; Cai, Lin; Lan, Yi; Tong, Haoya; Li, Yongxin; Jamieson, Alan J; Bajic, Vladimir B; Drazen, Jeffrey C; Bartlett, Douglas; Qian, Pei-Yuan

    2018-01-01

    Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth's oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by Psychromonas , of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living Psychromonas strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine N -oxide (TMAO) reducing gene cluster in CDP1, suggesting that the "piezolyte" function of TMAO is more important than its function in respiration, which may lead to TMAO accumulation. In terms of nutrient utilization, the bacterium retains its central carbohydrate metabolism but lacks most of the extended carbohydrate utilization pathways, suggesting the confinement of Psychromonas to the host gut and sequestration from more variable environmental conditions. Moreover, CDP1 contains a complete formate hydrogenlyase complex, which might be involved in energy production. The genomic analyses imply that CDP1 may have developed adaptive strategies for a lifestyle within the gut of the hadal amphipod H. gigas. IMPORTANCE As a unique but poorly investigated habitat within marine ecosystems, hadal trenches have received interest in recent years. This study explores the gut microbial composition and function in hadal amphipods, which are among the dominant carrion feeders in hadal habitats. Further analyses of a dominant strain revealed genomic features that may contribute to its adaptation to the amphipod gut environment. Our findings provide new insights into animal-associated bacteria in the hadal biosphere.

  5. Source of vacuum electromagnetic zero-point energy and Dirac's large numbers hypothesis

    International Nuclear Information System (INIS)

    Simaciu, I.; Dumitrescu, G.

    1993-01-01

    The stochastic electrodynamics states that zero-point fluctuation of the vacuum (ZPF) is an electromagnetic zero-point radiation with spectral density ρ(ω)=ℎω 3 / 2π 2 C 3 . Protons, free electrons and atoms are sources for this radiation. Each of them absorbs and emits energy by interacting with ZPF. At equilibrium ZPF radiation is scattered by dipoles.Scattered radiation spectral density is ρ(ω,r) ρ(ω).c.σ(ω) / 4πr 2 . Radiation of dipole spectral density of Universe is ρ ∫ 0 R nρ(ω,r)4πr 2 dr. But if σ atom P e σ=σ T then ρ ρ(ω)σ T R.n. Moreover if ρ=ρ(ω) then σ T Rn = 1. With R = G M/c 2 and σ T ≅(e 2 /m e c 2 ) 2 ∝ r e 2 then σ T .Rn 1 is equivalent to R/r e = e 2 /Gm p m e i.e. the cosmological coincidence discussed in the context of Dirac's large-numbers hypothesis. (Author)

  6. Application of random-point processes to the detection of radiation sources

    International Nuclear Information System (INIS)

    Woods, J.W.

    1978-01-01

    In this report the mathematical theory of random-point processes is reviewed and it is shown how use of the theory can obtain optimal solutions to the problem of detecting radiation sources. As noted, the theory also applies to image processing in low-light-level or low-count-rate situations. Paralleling Snyder's work, the theory is extended to the multichannel case of a continuous, two-dimensional (2-D), energy-time space. This extension essentially involves showing that the data are doubly stochastic Poisson (DSP) point processes in energy as well as time. Further, a new 2-D recursive formulation is presented for the radiation-detection problem with large computational savings over nonrecursive techniques when the number of channels is large (greater than or equal to 30). Finally, some adaptive strategies for on-line ''learning'' of unknown, time-varying signal and background-intensity parameters and statistics are present and discussed. These adaptive procedures apply when a complete statistical description is not available a priori

  7. Astronomers Detect Powerful Bursting Radio Source Discovery Points to New Class of Astronomical Objects

    Science.gov (United States)

    2005-03-01

    Astronomers at Sweet Briar College and the Naval Research Laboratory (NRL) have detected a powerful new bursting radio source whose unique properties suggest the discovery of a new class of astronomical objects. The researchers have monitored the center of the Milky Way Galaxy for several years and reveal their findings in the March 3, 2005 edition of the journal, “Nature”. This radio image of the central region of the Milky Way Galaxy holds a new radio source, GCRT J1745-3009. The arrow points to an expanding ring of debris expelled by a supernova. CREDIT: N.E. Kassim et al., Naval Research Laboratory, NRAO/AUI/NSF Principal investigator, Dr. Scott Hyman, professor of physics at Sweet Briar College, said the discovery came after analyzing some additional observations from 2002 provided by researchers at Northwestern University. “"We hit the jackpot!” Hyman said referring to the observations. “An image of the Galactic center, made by collecting radio waves of about 1-meter in wavelength, revealed multiple bursts from the source during a seven-hour period from Sept. 30 to Oct. 1, 2002 — five bursts in fact, and repeating at remarkably constant intervals.” Hyman, four Sweet Briar students, and his NRL collaborators, Drs. Namir Kassim and Joseph Lazio, happened upon transient emission from two radio sources while studying the Galactic center in 1998. This prompted the team to propose an ongoing monitoring program using the National Science Foundation’s Very Large Array (VLA) radio telescope in New Mexico. The National Radio Astronomy Observatory, which operates the VLA, approved the program. The data collected, laid the groundwork for the detection of the new radio source. “Amazingly, even though the sky is known to be full of transient objects emitting at X- and gamma-ray wavelengths,” NRL astronomer Dr. Joseph Lazio pointed out, “very little has been done to look for radio bursts, which are often easier for astronomical objects to produce

  8. An effective dose assessment technique with NORM added consumer products using skin-point source on computational human phantom

    International Nuclear Information System (INIS)

    Yoo, Do Hyeon; Shin, Wook-Geun; Lee, Hyun Cheol; Choi, Hyun Joon; Testa, Mauro; Lee, Jae Kook; Yeom, Yeon Soo; Kim, Chan Hyeong; Min, Chul Hee

    2016-01-01

    The aim of this study is to develop the assessment technique of the effective dose by calculating the organ equivalent dose with a Monte Carlo (MC) simulation and a computational human phantom for the naturally occurring radioactive material (NORM) added consumer products. In this study, we suggests the method determining the MC source term based on the skin-point source enabling the convenient and conservative modeling of the various type of the products. To validate the skin-point source method, the organ equivalent doses were compared with that by the product modeling source of the realistic shape for the pillow, waist supporter, sleeping mattress etc. Our results show that according to the source location, the organ equivalent doses were observed as the similar tendency for both source determining methods, however, it was observed that the annual effective dose with the skin-point source was conservative than that with the modeling source with the maximum 3.3 times higher dose. With the assumption of the gamma energy of 1 MeV and product activity of 1 Bq g"−"1, the annual effective doses of the pillow, waist supporter and sleeping mattress with skin-point source was 3.09E-16 Sv Bq"−"1 year"−"1, 1.45E-15 Sv Bq"−"1 year"−"1, and 2,82E-16 Sv Bq"−"1 year"−"1, respectively, while the product modeling source showed 9.22E-17 Sv Bq"−"1 year"−"1, 9.29E-16 Sv Bq"−"1 year"−"1, and 8.83E-17 Sv Bq"−"1 year"−"1, respectively. In conclusion, it was demonstrated in this study that the skin-point source method could be employed to efficiently evaluate the annual effective dose due to the usage of the NORM added consumer products. - Highlights: • We evaluate the exposure dose from the usage of NORM added consumer products. • We suggest the method determining the MC source term based on the skin-point source. • To validate the skin-point source, the organ equivalent doses were compared with that the modeling source. • The skin-point source could

  9. The percutaneous use of a pointed reduction clamp during intramedullary nailing of distal third tibial shaft fractures.

    Science.gov (United States)

    Forman, Jordanna M; Urruela, Adriana M; Egol, Kenneth A

    2011-12-01

    The purpose of this retrospective chart and radiographic review is to describe an effective reduction technique during intramedullary nailing of distal metaphyseal tibia fractures with the use of a pointed percutaneous clamp. Between 2007 and 2010, 100 patients who sustained 102 tibia fractures were definitively treated with an intramedullary nail at one of two medical centers. Diaphyseal fractures and injuries with an associated disruption of the distal tibiofibular joint were excluded from our study. A total of 27 patients with 27 distal metaphyseal tibia fractures (OTA types 42-A, 43-A, and 43-B) were included. All 27 patients underwent IM nailing of their fractures with anatomic reduction achieved using a percutaneously placed pointed reduction clamp prior to insertion of the IM implant. Fracture alignment and angular deformity was assessed using goniometric measurement functions on the PACS system (GE, Waukeshau, WI) obtained from preoperative and postoperative anteroposterior and lateral images for all subjects. Malalignment was defined as more than 5 degrees of angulation in any plane. Fourteen of the fractures were classified as OTA 42-A, 9 were OTA 43-A, and 4 were OTA 43-B. Analysis of post-closed reduction, preoperative anteroposterior radiographs revealed a mean of 7.9 degrees of coronal plane (range: 0.9 degrees-26 degrees) angulation. Post closed reduction preoperative lateral radiographs revealed a mean of 6.8 degrees sagittal plane (range: 0 degrees-24.6 degrees) angulation. Postoperative anteroposterior and lateral radiographs showed the distal segment returned to its anatomical alignment with a mean angulation of 0.5 degrees (range, 0 degrees-3.5 degrees) and 0.7 degrees (range, 0 degrees-4.2 degrees) of varus/ valgus and apex anterior/posterior angulation, respectively. These results showed an acceptable postopertative alignment in all 27 distal third fractures. No intra-operative or postoperative complications were noted in the study group. This

  10. Analysis of ultrasonically rotating droplet using moving particle semi-implicit and distributed point source methods

    Science.gov (United States)

    Wada, Yuji; Yuge, Kohei; Tanaka, Hiroki; Nakamura, Kentaro

    2016-07-01

    Numerical analysis of the rotation of an ultrasonically levitated droplet with a free surface boundary is discussed. The ultrasonically levitated droplet is often reported to rotate owing to the surface tangential component of acoustic radiation force. To observe the torque from an acoustic wave and clarify the mechanism underlying the phenomena, it is effective to take advantage of numerical simulation using the distributed point source method (DPSM) and moving particle semi-implicit (MPS) method, both of which do not require a calculation grid or mesh. In this paper, the numerical treatment of the viscoacoustic torque, which emerges from the viscous boundary layer and governs the acoustical droplet rotation, is discussed. The Reynolds stress traction force is calculated from the DPSM result using the idea of effective normal particle velocity through the boundary layer and input to the MPS surface particles. A droplet levitated in an acoustic chamber is simulated using the proposed calculation method. The droplet is vertically supported by a plane standing wave from an ultrasonic driver and subjected to a rotating sound field excited by two acoustic sources on the side wall with different phases. The rotation of the droplet is successfully reproduced numerically and its acceleration is discussed and compared with those in the literature.

  11. Lead in the blood of children living close to industrial point sources in Bulgaria and Poland

    Science.gov (United States)

    Willeke-Wetstein, C.; Bainova, A.; Georgieva, R.; Huzior-Balajewicz, A.; Bacon, J. R.

    2003-05-01

    ln Eastern European countries some industrial point sources are still suspected to have unacceptable emission rates of lead that pose a major health risk in particular to children. An interdisciplinary research project under the auspices of the EU had the aims (I) to monitor the current contamination of two industrial zones in Bulgaria and Poland, (2) to relate the Pb levels in ecological strata to the internal exposure of children, (3) to develop public health strategies in order to reduce the health risk by heavy metals. The human monitoring of Pb in Poland did not show increased health risks for the children living in an industrial zone close to Krakow. Bulgarian children, however, exceeded the WHO limit of 100 μg lead per litre blood by over one hundred percent (240 μg/1). Samples of soil, fodder and livestock organs showed elevated concentrations of lead. Recent literature results are compared with the findings in Bulgaria and Poland. The sources of the high internal exposure of children are discussed. Public health strategies to prevent mental dysfunction in Bulgarian children at risk include awareness building and social masures.

  12. Biosolid stockpiles are a significant point source for greenhouse gas emissions.

    Science.gov (United States)

    Majumder, Ramaprasad; Livesley, Stephen J; Gregory, David; Arndt, Stefan K

    2014-10-01

    The wastewater treatment process generates large amounts of sewage sludge that are dried and then often stored in biosolid stockpiles in treatment plants. Because the biosolids are rich in decomposable organic matter they could be a significant source for greenhouse gas (GHG) emissions, yet there are no direct measurements of GHG from stockpiles. We therefore measured the direct emissions of methane (CH4), nitrous oxide (N2O) and carbon dioxide (CO2) on a monthly basis from three different age classes of biosolid stockpiles at the Western Treatment Plant (WTP), Melbourne, Australia, from December 2009 to November 2011 using manual static chambers. All biosolid stockpiles were a significant point source for CH4 and N2O emissions. The youngest biosolids (nitrate and ammonium concentration. We also modeled CH4 emissions based on a first order decay model and the model based estimated annual CH4 emissions were higher as compared to the direct field based estimated annual CH4 emissions. Our results indicate that labile organic material in stockpiles is decomposed over time and that nitrogen decomposition processes lead to significant N2O emissions. Carbon decomposition favors CO2 over CH4 production probably because of aerobic stockpile conditions or CH4 oxidation in the outer stockpile layers. Although the GHG emission rate decreased with biosolid age, managers of biosolid stockpiles should assess alternate storage or uses for biosolids to avoid nutrient losses and GHG emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. NOx emissions from large point sources: variability in ozone production, resulting health damages and economic costs

    International Nuclear Information System (INIS)

    Mauzerall, D.L.; Namsoug Kim

    2005-01-01

    We present a proof-of-concept analysis of the measurement of the health damage of ozone (O 3 ) produced from nitrogen oxides (NO x =NO+NO 2 ) emitted by individual large point sources in the eastern United States. We use a regional atmospheric model of the eastern United States, the Comprehensive Air quality Model with Extensions (CAMx), to quantify the variable impact that a fixed quantity of NO x emitted from individual sources can have on the downwind concentration of surface O 3 , depending on temperature and local biogenic hydrocarbon emissions. We also examine the dependence of resulting O 3 -related health damages on the size of the exposed population. The investigation is relevant to the increasingly widely used 'cap and trade' approach to NO x regulation, which presumes that shifts of emission over time and space, holding the total fixed over the course of the summer O 3 season, will have minimal effect on the environmental outcome. By contrast, we show that a shift of a unit of NO x emissions from one place or time to another could result in large changes in resulting health effects due to O 3 formation and exposure. We indicate how the type of modeling carried out here might be used to attach externality-correcting prices to emissions. Charging emitters fees that are commensurate with the damage caused by their NO x emissions would create an incentive for emitters to reduce emissions at times and in locations where they cause the largest damage. (author)

  14. The energy sources and nuclear energy - The point of view of the Belgian Catholic Church

    International Nuclear Information System (INIS)

    Hoenraet, Christian

    2000-01-01

    The problems related to the environment are reported regularly to the public by means of the newspapers, on radio and television. The story is the product of a journalistic process and in general does not bear much resemblance to the original event. The rate and type of reportage depend not only on the body of data available to the journalist but on the information sources the journalist chosen to use. The same story is reported in a positive or negative way. Finally people are overwhelmed by contradictory information and became uncertain or frightened. In order to provide the general public with objective information about nuclear energy in particular and to made a statement about the position of the Belgian Catholic Church concerning this matter, the results of the study were published in Dutch under the form of a book with the title 'The Energy Sources and Nuclear Energy - Comparative analysis and ethical thoughts written the same author. Thia paper is a short survey of the results of the study and to present the point of view of the Belgian Catholic Church in the energy debate

  15. Eddy covariance methane flux measurements over a grazed pasture: effect of cows as moving point sources

    Science.gov (United States)

    Felber, R.; Münger, A.; Neftel, A.; Ammann, C.

    2015-06-01

    Methane (CH4) from ruminants contributes one-third of global agricultural greenhouse gas emissions. Eddy covariance (EC) technique has been extensively used at various flux sites to investigate carbon dioxide exchange of ecosystems. Since the development of fast CH4 analyzers, the instrumentation at many flux sites has been amended for these gases. However, the application of EC over pastures is challenging due to the spatially and temporally uneven distribution of CH4 point sources induced by the grazing animals. We applied EC measurements during one grazing season over a pasture with 20 dairy cows (mean milk yield: 22.7 kg d-1) managed in a rotational grazing system. Individual cow positions were recorded by GPS trackers to attribute fluxes to animal emissions using a footprint model. Methane fluxes with cows in the footprint were up to 2 orders of magnitude higher than ecosystem fluxes without cows. Mean cow emissions of 423 ± 24 g CH4 head-1 d-1 (best estimate from this study) correspond well to animal respiration chamber measurements reported in the literature. However, a systematic effect of the distance between source and EC tower on cow emissions was found, which is attributed to the analytical footprint model used. We show that the EC method allows one to determine CH4 emissions of cows on a pasture if the data evaluation is adjusted for this purpose and if some cow distribution information is available.

  16. Luminosity distribution in the central regions of Messier 87: Isothermal core, point source, or black hole

    International Nuclear Information System (INIS)

    de Vaucouleurs, G.; Nieto, J.

    1979-01-01

    A combination of photographic and photoelectric photometry with the McDonald 2 m reflector is used to derive a precise mean luminosity profile μ/sub B/(r*) of M87 (jet excluded) at approx.0''.6 resolution out to r*=70''. Within 8'' from the center the luminosity is less than predicted by extrapolation of the r/sup 1/4/ law defined by the main body of the galaxy (8'' 0 =30.5) the structural length of the underlying isothermal is α=2''.78=170 pc, the mass of the ''black hole'' M 0 =1.7.10 9 M/sub sun/ and the luminosity of the point source (B 0 =16.95, M 0 =-13.55) equals 4.2% of the integrated luminosity B (6'') =13.52 of the galaxy within r*=6''. These results agree closely with and confirm the work of the Hale team. Comparison of the McDonald and Hale data suggests that the central source may have been slightly brighter (approx.0.5 mag) in 1964 than in 1975--1977

  17. Point-source and diffuse high-energy neutrino emission from Type IIn supernovae

    Science.gov (United States)

    Petropoulou, M.; Coenders, S.; Vasilopoulos, G.; Kamble, A.; Sironi, L.

    2017-09-01

    Type IIn supernovae (SNe), a rare subclass of core collapse SNe, explode in dense circumstellar media that have been modified by the SNe progenitors at their last evolutionary stages. The interaction of the freely expanding SN ejecta with the circumstellar medium gives rise to a shock wave propagating in the dense SN environment, which may accelerate protons to multi-PeV energies. Inelastic proton-proton collisions between the shock-accelerated protons and those of the circumstellar medium lead to multimessenger signatures. Here, we evaluate the possible neutrino signal of Type IIn SNe and compare with IceCube observations. We employ a Monte Carlo method for the calculation of the diffuse neutrino emission from the SN IIn class to account for the spread in their properties. The cumulative neutrino emission is found to be ˜10 per cent of the observed IceCube neutrino flux above 60 TeV. Type IIn SNe would be the dominant component of the diffuse astrophysical flux, only if 4 per cent of all core collapse SNe were of this type and 20-30 per cent of the shock energy was channeled to accelerated protons. Lower values of the acceleration efficiency are accessible by the observation of a single Type IIn SN as a neutrino point source with IceCube using up-going muon neutrinos. Such an identification is possible in the first year following the SN shock breakout for sources within 20 Mpc.

  18. An ultrabright and monochromatic electron point source made of a LaB6 nanowire

    Science.gov (United States)

    Zhang, Han; Tang, Jie; Yuan, Jinshi; Yamauchi, Yasushi; Suzuki, Taku T.; Shinya, Norio; Nakajima, Kiyomi; Qin, Lu-Chang

    2016-03-01

    Electron sources in the form of one-dimensional nanotubes and nanowires are an essential tool for investigations in a variety of fields, such as X-ray computed tomography, flexible displays, chemical sensors and electron optics applications. However, field emission instability and the need to work under high-vacuum or high-temperature conditions have imposed stringent requirements that are currently limiting the range of application of electron sources. Here we report the fabrication of a LaB6 nanowire with only a few La atoms bonded on the tip that emits collimated electrons from a single point with high monochromaticity. The nanostructured tip has a low work function of 2.07 eV (lower than that of Cs) while remaining chemically inert, two properties usually regarded as mutually exclusive. Installed in a scanning electron microscope (SEM) field emission gun, our tip shows a current density gain that is about 1,000 times greater than that achievable with W(310) tips, and no emission decay for tens of hours of operation. Using this new SEM, we acquired very low-noise, high-resolution images together with rapid chemical compositional mapping using a tip operated at room temperature and at 10-times higher residual gas pressure than that required for W tips.

  19. Point sources of emerging contaminants along the Colorado River Basin: Source water for the arid Southwestern United States

    Science.gov (United States)

    Jones-Lepp, Tammy L.; Sanchez, Charles; Alvarez, David A.; Wilson, Doyle C.; Taniguchi-Fu, Randi-Laurant

    2012-01-01

    Emerging contaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the United States. The objective of this study was to evaluate point sources of ECs along the Colorado River, from the headwaters in Colorado to the Gulf of California. At selected locations in the Colorado River Basin (sites in Colorado, Utah, Nevada, Arizona, and California), waste stream tributaries and receiving surface waters were sampled using either grab sampling or polar organic chemical integrative samplers (POCIS). The grab samples were extracted using solid-phase cartridge extraction (SPE), and the POCIS sorbents were transferred into empty SPEs and eluted with methanol. All extracts were prepared for, and analyzed by, liquid chromatography–electrospray-ion trap mass spectrometry (LC–ESI-ITMS). Log DOW values were calculated for all ECs in the study and compared to the empirical data collected. POCIS extracts were screened for the presence of estrogenic chemicals using the yeast estrogen screen (YES) assay. Extracts from the 2008 POCIS deployment in the Las Vegas Wash showed the second highest estrogenicity response. In the grab samples, azithromycin (an antibiotic) was detected in all but one urban waste stream, with concentrations ranging from 30 ng/L to 2800 ng/L. Concentration levels of azithromycin, methamphetamine and pseudoephedrine showed temporal variation from the Tucson WWTP. Those ECs that were detected in the main surface water channels (those that are diverted for urban use and irrigation along the Colorado River) were in the region of the limit-of-detection (e.g., 10 ng/L), but most were below detection limits.

  20. Anthropogenic Methane Emissions in California's San Joaquin Valley: Characterizing Large Point Source Emitters

    Science.gov (United States)

    Hopkins, F. M.; Duren, R. M.; Miller, C. E.; Aubrey, A. D.; Falk, M.; Holland, L.; Hook, S. J.; Hulley, G. C.; Johnson, W. R.; Kuai, L.; Kuwayama, T.; Lin, J. C.; Thorpe, A. K.; Worden, J. R.; Lauvaux, T.; Jeong, S.; Fischer, M. L.

    2015-12-01

    Methane is an important atmospheric pollutant that contributes to global warming and tropospheric ozone production. Methane mitigation could reduce near term climate change and improve air quality, but is hindered by a lack of knowledge of anthropogenic methane sources. Recent work has shown that methane emissions are not evenly distributed in space, or across emission sources, suggesting that a large fraction of anthropogenic methane comes from a few "super-emitters." We studied the distribution of super-emitters in California's southern San Joaquin Valley, where elevated levels of atmospheric CH4 have also been observed from space. Here, we define super-emitters as methane plumes that could be reliably detected (i.e., plume observed more than once in the same location) under varying wind conditions by airborne thermal infrared remote sensing. The detection limit for this technique was determined to be 4.5 kg CH4 h-1 by a controlled release experiment, corresponding to column methane enhancement at the point of emissions greater than 20% above local background levels. We surveyed a major oil production field, and an area with a high concentration of large dairies using a variety of airborne and ground-based measurements. Repeated airborne surveys (n=4) with the Hyperspectral Thermal Emission Spectrometer revealed 28 persistent methane plumes emanating from oil field infrastructure, including tanks, wells, and processing facilities. The likelihood that a given source type was a super-emitter varied from roughly 1/3 for processing facilities to 1/3000 for oil wells. 11 persistent plumes were detected in the dairy area, and all were associated with wet manure management. The majority (11/14) of manure lagoons in the study area were super-emitters. Comparing to a California methane emissions inventory for the surveyed areas, we estimate that super-emitters comprise a minimum of 9% of inventoried dairy emissions, and 13% of inventoried oil emissions in this region.

  1. Using sorbent waste materials to enhance treatment of micro-point source effluents by constructed wetlands

    Science.gov (United States)

    Green, Verity; Surridge, Ben; Quinton, John; Matthews, Mike

    2014-05-01

    Sorbent materials are widely used in environmental settings as a means of enhancing pollution remediation. A key area of environmental concern is that of water pollution, including the need to treat micro-point sources of wastewater pollution, such as from caravan sites or visitor centres. Constructed wetlands (CWs) represent one means for effective treatment of wastewater from small wastewater producers, in part because they are believed to be economically viable and environmentally sustainable. Constructed wetlands have the potential to remove a range of pollutants found in wastewater, including nitrogen (N), phosphorus (P), biochemical oxygen demand (BOD) and carbon (C), whilst also reducing the total suspended solids (TSS) concentration in effluents. However, there remain particular challenges for P and N removal from wastewater in CWs, as well as the sometimes limited BOD removal within these treatment systems, particularly for micro-point sources of wastewater. It has been hypothesised that the amendment of CWs with sorbent materials can enhance their potential to treat wastewater, particularly through enhancing the removal of N and P. This paper focuses on data from batch and mesocosm studies that were conducted to identify and assess sorbent materials suitable for use within CWs. The aim in using sorbent material was to enhance the combined removal of phosphate (PO4-P) and ammonium (NH4-N). The key selection criteria for the sorbent materials were that they possess effective PO4-P, NH4-N or combined pollutant removal, come from low cost and sustainable sources, have potential for reuse, for example as a fertiliser or soil conditioner, and show limited potential for re-release of adsorbed nutrients. The sorbent materials selected for testing were alum sludge from water treatment works, ochre derived from minewater treatment, biochar derived from various feedstocks, plasterboard and zeolite. The performance of the individual sorbents was assessed through

  2. Prediction With Dimension Reduction of Multiple Molecular Data Sources for Patient Survival

    Directory of Open Access Journals (Sweden)

    Adam Kaplan

    2017-07-01

    Full Text Available Predictive modeling from high-dimensional genomic data is often preceded by a dimension reduction step, such as principal component analysis (PCA. However, the application of PCA is not straightforward for multisource data, wherein multiple sources of ‘omics data measure different but related biological components. In this article, we use recent advances in the dimension reduction of multisource data for predictive modeling. In particular, we apply exploratory results from Joint and Individual Variation Explained (JIVE, an extension of PCA for multisource data, for prediction of differing response types. We conduct illustrative simulations to illustrate the practical advantages and interpretability of our approach. As an application example, we consider predicting survival for patients with glioblastoma multiforme from 3 data sources measuring messenger RNA expression, microRNA expression, and DNA methylation. We also introduce a method to estimate JIVE scores for new samples that were not used in the initial dimension reduction and study its theoretical properties; this method is implemented in the R package R.JIVE on CRAN, in the function jive.predict.

  3. Numerical study and ex vivo assessment of HIFU treatment time reduction through optimization of focal point trajectory

    Science.gov (United States)

    Grisey, A.; Yon, S.; Pechoux, T.; Letort, V.; Lafitte, P.

    2017-03-01

    Treatment time reduction is a key issue to expand the use of high intensity focused ultrasound (HIFU) surgery, especially for benign pathologies. This study aims at quantitatively assessing the potential reduction of the treatment time arising from moving the focal point during long pulses. In this context, the optimization of the focal point trajectory is crucial to achieve a uniform thermal dose repartition and avoid boiling. At first, a numerical optimization algorithm was used to generate efficient trajectories. Thermal conduction was simulated in 3D with a finite difference code and damages to the tissue were modeled using the thermal dose formula. Given an initial trajectory, the thermal dose field was first computed, then, making use of Pontryagin's maximum principle, the trajectory was iteratively refined. Several initial trajectories were tested. Then, an ex vivo study was conducted in order to validate the efficicency of the resulting optimized strategies. Single pulses were performed at 3MHz on fresh veal liver samples with an Echopulse and the size of each unitary lesion was assessed by cutting each sample along three orthogonal planes and measuring the dimension of the whitened area based on photographs. We propose a promising approach to significantly shorten HIFU treatment time: the numerical optimization algorithm was shown to provide a reliable insight on trajectories that can improve treatment strategies. The model must now be improved in order to take in vivo conditions into account and extensively validated.

  4. The recovery of a time-dependent point source in a linear transport equation: application to surface water pollution

    International Nuclear Information System (INIS)

    Hamdi, Adel

    2009-01-01

    The aim of this paper is to localize the position of a point source and recover the history of its time-dependent intensity function that is both unknown and constitutes the right-hand side of a 1D linear transport equation. Assuming that the source intensity function vanishes before reaching the final control time, we prove that recording the state with respect to the time at two observation points framing the source region leads to the identification of the source position and the recovery of its intensity function in a unique manner. Note that at least one of the two observation points should be strategic. We establish an identification method that determines quasi-explicitly the source position and transforms the task of recovering its intensity function into solving directly a well-conditioned linear system. Some numerical experiments done on a variant of the water pollution BOD model are presented

  5. New insights into the reduction systems of plastidial thioredoxins point out the unique properties of thioredoxin z from Arabidopsis.

    Science.gov (United States)

    Bohrer, Anne-Sophie; Massot, Vincent; Innocenti, Gilles; Reichheld, Jean-Philippe; Issakidis-Bourguet, Emmanuelle; Vanacker, Hélène

    2012-11-01

    In plants, thioredoxins (TRX) constitute a large protein disulphide oxidoreductase family comprising 10 plastidial members in Arabidopsis thaliana and subdivided in five types. The f- and m-types regulate enzymes involved mainly in carbon metabolism whereas the x, y, and z types have an antioxidant function. The reduction of TRXm and f in chloroplasts is performed in the light by ferredoxin:thioredoxin reductase (FTR) that uses photosynthetically reduced ferredoxin (Fd) as a reductant. The reduction system of Arabidopsis TRXx, y, and z has never been demonstrated. Recently, a gene encoding an atypical plastidial NADPH-dependent TRX reductase (NTRC) was found. In the present study, gene expression analysis revealed that both reductases are expressed in all organs of Arabidopsis and could potentially serve as electron donors to plastidial TRX. This ability was tested in vitro either with purified NTRC in presence of NADPH or with a light-driven reconstituted system comprising thylakoids and purified Fd and FTR. The results demonstrate that FTR reduces the x and y TRX isoforms but not the recently identified TRXz. Moreover, the results show that NTRC cannot be an efficient alternative reducing system, neither for TRXz nor for the other plastidial TRX. The data reveal that TRXf, m, x, and y, known as redox regulators in the chloroplast, have also the ability to reduce TRXz in vitro. Overall, the present study points out the unique properties of TRXz among plastidial TRX.

  6. Coupling aerosol-cloud-radiative processes in the WRF-Chem model: Investigating the radiative impact of elevated point sources

    Directory of Open Access Journals (Sweden)

    E. G. Chapman

    2009-02-01

    resolution model domain (the extent of which corresponds to the typical size of a single global climate model grid cell and temporally over a three day analysis period, total rainfall in the sensitivity simulation increased by 31% over that in the baseline simulation. Fewer optically thin clouds, arbitrarily defined as a cloud exhibiting an optical depth less than 1, formed in the sensitivity simulation. Domain-averaged AODs dropped from 0.46 in the baseline simulation to 0.38 in the sensitivity simulation. The overall net effect of additional aerosols attributable to primary particulates and aerosol precursors from point source emissions above the surface was a domain-averaged reduction of 5 W m−2 in mean daytime downwelling shortwave radiation.

  7. Atmospheric observations and inverse modelling for quantifying emissions of point-source synthetic greenhouse gases in East Asia

    Science.gov (United States)

    Arnold, Tim; Manning, Alistair; Li, Shanlan; Kim, Jooil; Park, Sunyoung; Muhle, Jens; Weiss, Ray

    2017-04-01

    that the impact of these long-lived gases could rise significantly and that point sources of such gases can be mitigated, atmospheric monitoring could be an important tool for aiding emissions reduction policy.

  8. A Numerical Study on the Excitation of Guided Waves in Rectangular Plates Using Multiple Point Sources

    Directory of Open Access Journals (Sweden)

    Wenbo Duan

    2017-12-01

    Full Text Available Ultrasonic guided waves are widely used to inspect and monitor the structural integrity of plates and plate-like structures, such as ship hulls and large storage-tank floors. Recently, ultrasonic guided waves have also been used to remove ice and fouling from ship hulls, wind-turbine blades and aeroplane wings. In these applications, the strength of the sound source must be high for scanning a large area, or to break the bond between ice, fouling and plate substrate. More than one transducer may be used to achieve maximum sound power output. However, multiple sources can interact with each other, and form a sound field in the structure with local constructive and destructive regions. Destructive regions are weak regions and shall be avoided. When multiple transducers are used it is important that they are arranged in a particular way so that the desired wave modes can be excited to cover the whole structure. The objective of this paper is to provide a theoretical basis for generating particular wave mode patterns in finite-width rectangular plates whose length is assumed to be infinitely long with respect to its width and thickness. The wave modes have displacements in both width and thickness directions, and are thus different from the classical Lamb-type wave modes. A two-dimensional semi-analytical finite element (SAFE method was used to study dispersion characteristics and mode shapes in the plate up to ultrasonic frequencies. The modal analysis provided information on the generation of modes suitable for a particular application. The number of point sources and direction of loading for the excitation of a few representative modes was investigated. Based on the SAFE analysis, a standard finite element modelling package, Abaqus, was used to excite the designed modes in a three-dimensional plate. The generated wave patterns in Abaqus were then compared with mode shapes predicted in the SAFE model. Good agreement was observed between the

  9. Effects of pointing compared with naming and observing during encoding on item and source memory in young and older adults.

    Science.gov (United States)

    Ouwehand, Kim; van Gog, Tamara; Paas, Fred

    2016-10-01

    Research showed that source memory functioning declines with ageing. Evidence suggests that encoding visual stimuli with manual pointing in addition to visual observation can have a positive effect on spatial memory compared with visual observation only. The present study investigated whether pointing at picture locations during encoding would lead to better spatial source memory than naming (Experiment 1) and visual observation only (Experiment 2) in young and older adults. Experiment 3 investigated whether response modality during the test phase would influence spatial source memory performance. Experiments 1 and 2 supported the hypothesis that pointing during encoding led to better source memory for picture locations than naming or observation only. Young adults outperformed older adults on the source memory but not the item memory task in both Experiments 1 and 2. In Experiments 1 and 2, participants manually responded in the test phase. Experiment 3 showed that if participants had to verbally respond in the test phase, the positive effect of pointing compared with naming during encoding disappeared. The results suggest that pointing at picture locations during encoding can enhance spatial source memory in both young and older adults, but only if the response modality is congruent in the test phase.

  10. Active control on high-order coherence and statistic characterization on random phase fluctuation of two classical point sources.

    Science.gov (United States)

    Hong, Peilong; Li, Liming; Liu, Jianji; Zhang, Guoquan

    2016-03-29

    Young's double-slit or two-beam interference is of fundamental importance to understand various interference effects, in which the stationary phase difference between two beams plays the key role in the first-order coherence. Different from the case of first-order coherence, in the high-order optical coherence the statistic behavior of the optical phase will play the key role. In this article, by employing a fundamental interfering configuration with two classical point sources, we showed that the high- order optical coherence between two classical point sources can be actively designed by controlling the statistic behavior of the relative phase difference between two point sources. Synchronous position Nth-order subwavelength interference with an effective wavelength of λ/M was demonstrated, in which λ is the wavelength of point sources and M is an integer not larger than N. Interestingly, we found that the synchronous position Nth-order interference fringe fingerprints the statistic trace of random phase fluctuation of two classical point sources, therefore, it provides an effective way to characterize the statistic properties of phase fluctuation for incoherent light sources.

  11. Experimental properties of gluon and quark jets from a point source

    CERN Document Server

    Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Blobel, V.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Folman, R.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon, J.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hoch, M.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lautenschlager, S.R.; Lawson, I.; Layter, J.G.; Lee, A.M.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Markopoulos, C.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Menke, S.; Merritt, F.S.; Mes, H.; Meyer, J.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mir, R.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Oreglia, M.J.; Orito, S.; Palinkas, J.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turcot, A.S.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Yekutieli, G.; Zacek, V.; Zer-Zion, D.

    1999-01-01

    Gluon jets are identified in hadronic Z0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large transverse momentum, we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29 +- 0.09 +- 0.15 in agreement with the prediction that this ratio should ap...

  12. Novel Remarks on Point Mass Sources, Firewalls, Null Singularities and Gravitational Entropy

    Science.gov (United States)

    Perelman, Carlos Castro

    2016-01-01

    A continuous family of static spherically symmetric solutions of Einstein's vacuum field equations with a spatial singularity at the origin r = 0 is found. These solutions are parametrized by a real valued parameter λ (ranging from 0 to 1) and such that the radial horizon's location is displaced continuously towards the singularity ( r = 0 ) as λ increases. In the extreme limit λ = 1, the location of the singularity and horizon merges leading to a null singularity. In this extreme case, any infalling observer hits the null singularity at the very moment he/she crosses the horizon. This fact may have important consequences for the resolution of the fire wall problem and the complementarity controversy in black holes. An heuristic argument is provided how one might avoid the Hawking particle emission process in this extreme case when the singularity and horizon merges. The field equations due to a delta-function point-mass source at r = 0 are solved and the Euclidean gravitational action corresponding to those solutions is evaluated explicitly. It is found that the Euclidean action is precisely equal to the black hole entropy (in Planck area units). This result holds in any dimensions D ≥ 3.

  13. Application of distributed point source method (DPSM) to wave propagation in anisotropic media

    Science.gov (United States)

    Fooladi, Samaneh; Kundu, Tribikram

    2017-04-01

    Distributed Point Source Method (DPSM) was developed by Placko and Kundu1, as a technique for modeling electromagnetic and elastic wave propagation problems. DPSM has been used for modeling ultrasonic, electrostatic and electromagnetic fields scattered by defects and anomalies in a structure. The modeling of such scattered field helps to extract valuable information about the location and type of defects. Therefore, DPSM can be used as an effective tool for Non-Destructive Testing (NDT). Anisotropy adds to the complexity of the problem, both mathematically and computationally. Computation of the Green's function which is used as the fundamental solution in DPSM is considerably more challenging for anisotropic media, and it cannot be reduced to a closed-form solution as is done for isotropic materials. The purpose of this study is to investigate and implement DPSM for an anisotropic medium. While the mathematical formulation and the numerical algorithm will be considered for general anisotropic media, more emphasis will be placed on transversely isotropic materials in the numerical example presented in this paper. The unidirectional fiber-reinforced composites which are widely used in today's industry are good examples of transversely isotropic materials. Development of an effective and accurate NDT method based on these modeling results can be of paramount importance for in-service monitoring of damage in composite structures.

  14. Economic-environmental modeling of point source pollution in Jefferson County, Alabama, USA.

    Science.gov (United States)

    Kebede, Ellene; Schreiner, Dean F; Huluka, Gobena

    2002-05-01

    This paper uses an integrated economic-environmental model to assess the point source pollution from major industries in Jefferson County, Northern Alabama. Industrial expansion generates employment, income, and tax revenue for the public sector; however, it is also often associated with the discharge of chemical pollutants. Jefferson County is one of the largest industrial counties in Alabama that experienced smog warnings and ambient ozone concentration, 1996-1999. Past studies of chemical discharge from industries have used models to assess the pollution impact of individual plants. This study, however, uses an extended Input-Output (I-O) economic model with pollution emission coefficients to assess direct and indirect pollutant emission for several major industries in Jefferson County. The major findings of the study are: (a) the principal emission by the selected industries are volatile organic compounds (VOC) and these contribute to the ambient ozone concentration; (b) the direct and indirect emissions are significantly higher than the direct emission by some industries, indicating that an isolated analysis will underestimate the emission by an industry; (c) while low emission coefficient industries may suggest industry choice they may also emit the most hazardous chemicals. This study is limited by the assumptions made, and the data availability, however it provides a useful analytical tool for direct and cumulative emission estimation and generates insights on the complexity in choice of industries.

  15. Science, information, technology, and the changing character of public policy in non-point source pollution

    Science.gov (United States)

    King, John L.; Corwin, Dennis L.

    Information technologies are already delivering important new capabilities for scientists working on non-point source (NPS) pollution in the vadose zone, and more are expected. This paper focuses on the special contributions of modeling and network communications for enhancing the effectiveness of scientists in the realm of policy debates regarding NPS pollution mitigation and abatement. The discussion examines a fundamental shift from a strict regulatory strategy of pollution control characterized by a bureaucratic/technical alliance during the period through the 1970's and early 1980's, to a more recently evolving paradigm of pluralistic environmental management. The role of science and scientists in this shift is explored, with special attention to the challenges facing scientists working in NPS pollution in the vadose zone. These scientists labor under a special handicap in the evolving model because their scientific tools are often times incapable of linking NPS pollution with individuals responsible for causing it. Information can facilitate the effectiveness of these scientists in policy debates, but not under the usual assumptions in which scientific truth prevails. Instead, information technology's key role is in helping scientists shape the evolving discussion of trade-offs and in bringing citizens and policymakers closer to the routine work of scientists.

  16. Using a dynamic point-source percolation model to simulate bubble growth

    International Nuclear Information System (INIS)

    Zimmerman, Jonathan A.; Zeigler, David A.; Cowgill, Donald F.

    2004-01-01

    Accurate modeling of nucleation, growth and clustering of helium bubbles within metal tritide alloys is of high scientific and technological importance. Of interest is the ability to predict both the distribution of these bubbles and the manner in which these bubbles interact at a critical concentration of helium-to-metal atoms to produce an accelerated release of helium gas. One technique that has been used in the past to model these materials, and again revisited in this research, is percolation theory. Previous efforts have used classical percolation theory to qualitatively and quantitatively model the behavior of interstitial helium atoms in a metal tritide lattice; however, higher fidelity models are needed to predict the distribution of helium bubbles and include features that capture the underlying physical mechanisms present in these materials. In this work, we enhance classical percolation theory by developing the dynamic point-source percolation model. This model alters the traditionally binary character of site occupation probabilities by enabling them to vary depending on proximity to existing occupied sites, i.e. nucleated bubbles. This revised model produces characteristics for one and two dimensional systems that are extremely comparable with measurements from three dimensional physical samples. Future directions for continued development of the dynamic model are also outlined

  17. pH control for enhanced reductive bioremediation of chlorinated solvent source zones

    International Nuclear Information System (INIS)

    Robinson, Clare; Barry, D.A.; McCarty, Perry L.; Gerhard, Jason I.; Kouznetsova, Irina

    2009-01-01

    Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

  18. pH control for enhanced reductive bioremediation of chlorinated solvent source zones

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Clare, E-mail: clare.robinson@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Barry, D.A., E-mail: andrew.barry@epfl.ch [Laboratoire de technologie ecologique, Institut d' ingenierie de l' environnement, Station No. 2, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); McCarty, Perry L., E-mail: pmccarty@stanford.edu [Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020 (United States); Gerhard, Jason I., E-mail: j.gerhard@ed.ac.uk [Now at: Department of Civil and Environmental Engineering, University of Western Ontario, London, Canada N6A 5B9 (Canada); Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom); Kouznetsova, Irina, E-mail: irina.kouznetsova@ed.ac.uk [Institute for Infrastructure and Environment, University of Edinburgh, Edinburgh, EH9 3JL (United Kingdom)

    2009-08-01

    Enhanced reductive dehalogenation is an attractive treatment technology for in situ remediation of chlorinated solvent DNAPL source areas. Reductive dehalogenation is an acid-forming process with hydrochloric acid and also organic acids from fermentation of the electron donors typically building up in the source zone during remediation. This can lead to groundwater acidification thereby inhibiting the activity of dehalogenating microorganisms. Where the soils' natural buffering capacity is likely to be exceeded, the addition of an external source of alkalinity is needed to ensure sustained dehalogenation. To assist in the design of bioremediation systems, an abiotic geochemical model was developed to provide insight into the processes influencing the groundwater acidity as dehalogenation proceeds, and to predict the amount of bicarbonate required to maintain the pH at a suitable level for dehalogenating bacteria (i.e., > 6.5). The model accounts for the amount of chlorinated solvent degraded, site water chemistry, electron donor, alternative terminal electron-accepting processes, gas release and soil mineralogy. While calcite and iron oxides were shown to be the key minerals influencing the soil's buffering capacity, for the extensive dehalogenation likely to occur in a DNAPL source zone, significant bicarbonate addition may be necessary even in soils that are naturally well buffered. Results indicated that the bicarbonate requirement strongly depends on the electron donor used and availability of competing electron acceptors (e.g., sulfate, iron (III)). Based on understanding gained from this model, a simplified model was developed for calculating a preliminary design estimate of the bicarbonate addition required to control the pH for user-specified operating conditions.

  19. Geometric constraints in semiclassical initial value representation calculations in Cartesian coordinates: accurate reduction in zero-point energy.

    Science.gov (United States)

    Issack, Bilkiss B; Roy, Pierre-Nicholas

    2005-08-22

    An approach for the inclusion of geometric constraints in semiclassical initial value representation calculations is introduced. An important aspect of the approach is that Cartesian coordinates are used throughout. We devised an algorithm for the constrained sampling of initial conditions through the use of multivariate Gaussian distribution based on a projected Hessian. We also propose an approach for the constrained evaluation of the so-called Herman-Kluk prefactor in its exact log-derivative form. Sample calculations are performed for free and constrained rare-gas trimers. The results show that the proposed approach provides an accurate evaluation of the reduction in zero-point energy. Exact basis set calculations are used to assess the accuracy of the semiclassical results. Since Cartesian coordinates are used, the approach is general and applicable to a variety of molecular and atomic systems.

  20. Five-Level Z-Source Neutral Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper proposes a five-level Z-source neutralpoint- clamped (NPC) inverter with two Z-source networks functioning as intermediate energy storages coupled between dc sources and NPC inverter circuitry. Analyzing the operational principles of Z-source network with partial dclink shoot......-through scheme reveals the hidden theories in the five-level Z-source NPC inverter unlike the operational principle appeared in the general two-level Z-source inverter, so that the five-level Z-source NPC inverter can be designed with the modulation of carrier-based phase disposition (PD) or alternative phase...

  1. Fast space-varying convolution using matrix source coding with applications to camera stray light reduction.

    Science.gov (United States)

    Wei, Jianing; Bouman, Charles A; Allebach, Jan P

    2014-05-01

    Many imaging applications require the implementation of space-varying convolution for accurate restoration and reconstruction of images. Here, we use the term space-varying convolution to refer to linear operators whose impulse response has slow spatial variation. In addition, these space-varying convolution operators are often dense, so direct implementation of the convolution operator is typically computationally impractical. One such example is the problem of stray light reduction in digital cameras, which requires the implementation of a dense space-varying deconvolution operator. However, other inverse problems, such as iterative tomographic reconstruction, can also depend on the implementation of dense space-varying convolution. While space-invariant convolution can be efficiently implemented with the fast Fourier transform, this approach does not work for space-varying operators. So direct convolution is often the only option for implementing space-varying convolution. In this paper, we develop a general approach to the efficient implementation of space-varying convolution, and demonstrate its use in the application of stray light reduction. Our approach, which we call matrix source coding, is based on lossy source coding of the dense space-varying convolution matrix. Importantly, by coding the transformation matrix, we not only reduce the memory required to store it; we also dramatically reduce the computation required to implement matrix-vector products. Our algorithm is able to reduce computation by approximately factoring the dense space-varying convolution operator into a product of sparse transforms. Experimental results show that our method can dramatically reduce the computation required for stray light reduction while maintaining high accuracy.

  2. Evaluation of spatial dependence of point spread function-based PET reconstruction using a traceable point-like 22Na source

    Directory of Open Access Journals (Sweden)

    Taisuke Murata

    2016-10-01

    Full Text Available Abstract Background The point spread function (PSF of positron emission tomography (PET depends on the position across the field of view (FOV. Reconstruction based on PSF improves spatial resolution and quantitative accuracy. The present study aimed to quantify the effects of PSF correction as a function of the position of a traceable point-like 22Na source over the FOV on two PET scanners with a different detector design. Methods We used Discovery 600 and Discovery 710 (GE Healthcare PET scanners and traceable point-like 22Na sources (<1 MBq with a spherical absorber design that assures uniform angular distribution of the emitted annihilation photons. The source was moved in three directions at intervals of 1 cm from the center towards the peripheral FOV using a three-dimensional (3D-positioning robot, and data were acquired over a period of 2 min per point. The PET data were reconstructed by filtered back projection (FBP, the ordered subset expectation maximization (OSEM, OSEM + PSF, and OSEM + PSF + time-of-flight (TOF. Full width at half maximum (FWHM was determined according to the NEMA method, and total counts in regions of interest (ROI for each reconstruction were quantified. Results The radial FWHM of FBP and OSEM increased towards the peripheral FOV, whereas PSF-based reconstruction recovered the FWHM at all points in the FOV of both scanners. The radial FWHM for PSF was 30–50 % lower than that of OSEM at the center of the FOV. The accuracy of PSF correction was independent of detector design. Quantitative values were stable across the FOV in all reconstruction methods. The effect of TOF on spatial resolution and quantitation accuracy was less noticeable. Conclusions The traceable 22Na point-like source allowed the evaluation of spatial resolution and quantitative accuracy across the FOV using different reconstruction methods and scanners. PSF-based reconstruction reduces dependence of the spatial resolution on the

  3. Exact analytical solution of time-independent neutron transport equation, and its applications to systems with a point source

    International Nuclear Information System (INIS)

    Mikata, Y.

    2014-01-01

    Highlights: • An exact solution for the one-speed neutron transport equation is obtained. • This solution as well as its derivation are believed to be new. • Neutron flux for a purely absorbing material with a point neutron source off the origin is obtained. • Spherically as well as cylindrically piecewise constant cross sections are studied. • Neutron flux expressions for a point neutron source off the origin are believed to be new. - Abstract: An exact analytical solution of the time-independent monoenergetic neutron transport equation is obtained in this paper. The solution is applied to systems with a point source. Systematic analysis of the solution of the time-independent neutron transport equation, and its applications represent the primary goal of this paper. To the best of the author’s knowledge, certain key results on the scalar neutron flux as well as their derivations are new. As an application of these results, a scalar neutron flux for a purely absorbing medium with a spherically piecewise constant cross section and an isotropic point neutron source off the origin as well as that for a cylindrically piecewise constant cross section with a point neutron source off the origin are obtained. Both of these results are believed to be new

  4. The Treatment Train approach to reducing non-point source pollution from agriculture

    Science.gov (United States)

    Barber, N.; Reaney, S. M.; Barker, P. A.; Benskin, C.; Burke, S.; Cleasby, W.; Haygarth, P.; Jonczyk, J. C.; Owen, G. J.; Snell, M. A.; Surridge, B.; Quinn, P. F.

    2016-12-01

    An experimental approach has been applied to an agricultural catchment in NW England, where non-point pollution adversely affects freshwater ecology. The aim of the work (as part of the River Eden Demonstration Test Catchment project) is to develop techniques to manage agricultural runoff whilst maintaining food production. The approach used is the Treatment Train (TT), which applies multiple connected mitigation options that control nutrient and fine sediment pollution at source, and address polluted runoff pathways at increasing spatial scale. The principal agricultural practices in the study sub-catchment (1.5 km2) are dairy and stock production. Farm yards can act as significant pollution sources by housing large numbers of animals; these areas are addressed initially with infrastructure improvements e.g. clean/dirty water separation and upgraded waste storage. In-stream high resolution monitoring of hydrology and water quality parameters showed high-discharge events to account for the majority of pollutant exports ( 80% total phosphorus; 95% fine sediment), and primary transfer routes to be surface and shallow sub-surface flow pathways, including drains. To manage these pathways and reduce hydrological connectivity, a series of mitigation features were constructed to intercept and temporarily store runoff. Farm tracks, field drains, first order ditches and overland flow pathways were all targeted. The efficacy of the mitigation features has been monitored at event and annual scale, using inflow-outflow sampling and sediment/nutrient accumulation measurements, respectively. Data presented here show varied but positive results in terms of reducing acute and chronic sediment and nutrient losses. An aerial fly-through of the catchment is used to demonstrate how the TT has been applied to a fully-functioning agricultural landscape. The elevated perspective provides a better understanding of the spatial arrangement of mitigation features, and how they can be

  5. Non-point Source Pollution Modeling Using Geographic Information System (GIS for Representing Best Management Practices (BMP in the Gorganrood Watershed

    Directory of Open Access Journals (Sweden)

    Z. Pasandidehfard

    2014-09-01

    Full Text Available The most important pollutants that cause water pollution are nitrogen and phosphorus from agricultural runoff called Non-Point Source Pollution (NPS. To solve this problem, management practices known as BMPs or Best Management Practices are applied. One of the common methods for Non-Point Source Pollution prediction is modeling. By modeling, efficiency of many practices can be tested before application. In this study, land use changes were studied from the years 1984 till 2010 that showed an increase in agricultural lands from 516908.52 to 630737.19 ha and expansion of cities from 5237.87 to 15487.59 ha and roads from 9666.07 to 11430.24 ha. Using L-THIA model (from nonpoint source pollution models for both land use categories, the amount of pollutant and the volume of runoff were calculated that showed high growth. Then, the seventh sub-basin was recognized as a critical zone in terms of pollution among the sub-basins. In the end, land use change was considered as a BMP using Multi-Criteria Evaluation (MCE based on which a more suitable land use map was produced. After producing the new land use map, L-THIA model was run again and the result of the model was compared to the actual land use to show the effect of this BMP. Runoff volume decreased from 367.5 to 308.6 M3/ha and nitrogen in runoff was reduced from 3.26 to 1.58 mg/L and water BOD from 3.61 to 2.13 mg/L. Other pollutants also showed high reduction. In the end, land use change is confirmed as an effective BMP for Non-Point Source Pollution reduction.

  6. Endogenous NO3- in the root as a source of substrate for reduction in the light

    International Nuclear Information System (INIS)

    Rufty, T.W. Jr.; Volk, R.J.; MacKown, C.T.

    1987-01-01

    An experiment was conducted to investigate the reduction of endogenous NO 3 - , which had been taken up by plants in darkness, during the course of the subsequent light period. Vegetative, nonnodulated soybean plant (Glycine max [L.]. Merrill, Ransom) were exposed to 1.0 millimolar 15 NO 3 - for 12 hours in darkness and then returned to a solution containing 1.0 millimolar 14 NO 3 - for the 12 hours chase period in the light. Another set of plants was exposed to 15 NO 3 - during the light period to allow a direct comparison of contributions of substrate from the endogenous and exogenous sources. At the end of the 15 NO 3 - exposure in the dark, 70% of the absorbed 15 NO 3 - remained unreduced, and 83% of this unreduced NO 3 - was retained in roots. The pool of endogenous 15 NO 3 - in roots was depleted at a steady rate during the initial 9 hours of light and was utilized almost exclusively in the formation of insoluble reduced-N in leaves. Unlabeled endogenous NO 3 - , which had accumulated in the root prior to the previous dark period, also was depleted in the light. When exogenous 15 NO 3 - was supplied during the light period, the rate of assimilation progressively increased, reflecting an increased rate of uptake and decreased accumulation of NO 3 - in the root tissue. The dark-absorbed endogenous NO 3 - in the root was the primary source of substrate for whole-plant NO 3 - reduction in the first 6 hours of the light period, and exogenous NO 3 - was the primary source of substrate thereafter

  7. Mycotoxins: diffuse and point source contributions of natural contaminants of emerging concern to streams

    Science.gov (United States)

    Kolpin, Dana W.; Schenzel, Judith; Meyer, Michael T.; Phillips, Patrick J.; Hubbard, Laura E.; Scott, Tia-Marie; Bucheli, Thomas D.

    2014-01-01

    To determine the prevalence of mycotoxins in streams, 116 water samples from 32 streams and three wastewater treatment plant effluents were collected in 2010 providing the broadest investigation on the spatial and temporal occurrence of mycotoxins in streams conducted in the United States to date. Out of the 33 target mycotoxins measured, nine were detected at least once during this study. The detections of mycotoxins were nearly ubiquitous during this study even though the basin size spanned four orders of magnitude. At least one mycotoxin was detected in 94% of the 116 samples collected. Deoxynivalenol was the most frequently detected mycotoxin (77%), followed by nivalenol (59%), beauvericin (43%), zearalenone (26%), β-zearalenol (20%), 3-acetyl-deoxynivalenol (16%), α-zearalenol (10%), diacetoxyscirpenol (5%), and verrucarin A (1%). In addition, one or more of the three known estrogenic compounds (i.e. zearalenone, α-zearalenol, and β-zearalenol) were detected in 43% of the samples, with maximum concentrations substantially higher than observed in previous research. While concentrations were generally low (i.e. < 50 ng/L) during this study, concentrations exceeding 1000 ng/L were measured during spring snowmelt conditions in agricultural settings and in wastewater treatment plant effluent. Results of this study suggest that both diffuse (e.g. release from infected plants and manure applications from exposed livestock) and point (e.g. wastewater treatment plants and food processing plants) sources are important environmental pathways for mycotoxin transport to streams. The ecotoxicological impacts from the long-term, low-level exposures to mycotoxins alone or in combination with complex chemical mixtures are unknown

  8. Interpolating precipitation and its relation to runoff and non-point source pollution.

    Science.gov (United States)

    Chang, Chia-Ling; Lo, Shang-Lien; Yu, Shaw-L

    2005-01-01

    When rainfall spatially varies, complete rainfall data for each region with different rainfall characteristics are very important. Numerous interpolation methods have been developed for estimating unknown spatial characteristics. However, no interpolation method is suitable for all circumstances. In this study, several methods, including the arithmetic average method, the Thiessen Polygons method, the traditional inverse distance method, and the modified inverse distance method, were used to interpolate precipitation. The modified inverse distance method considers not only horizontal distances but also differences between the elevations of the region with no rainfall records and of its surrounding rainfall stations. The results show that when the spatial variation of rainfall is strong, choosing a suitable interpolation method is very important. If the rainfall is uniform, the precipitation estimated using any interpolation method would be quite close to the actual precipitation. When rainfall is heavy in locations with high elevation, the rainfall changes with the elevation. In this situation, the modified inverse distance method is much more effective than any other method discussed herein for estimating the rainfall input for WinVAST to estimate runoff and non-point source pollution (NPSP). When the spatial variation of rainfall is random, regardless of the interpolation method used to yield rainfall input, the estimation errors of runoff and NPSP are large. Moreover, the relationship between the relative error of the predicted runoff and predicted pollutant loading of SS is high. However, the pollutant concentration is affected by both runoff and pollutant export, so the relationship between the relative error of the predicted runoff and the predicted pollutant concentration of SS may be unstable.

  9. Relationship Between Non-Point Source Pollution and Korean Green Factor

    Directory of Open Access Journals (Sweden)

    Seung Chul Lee

    2015-01-01

    Full Text Available In determining the relationship between the rational event mean concentration (REMC which is a volume-weighted mean of event mean concentrations (EMCs as a non-point source (NPS pollution indicator and the green factor (GF as a low impact development (LID land use planning indicator, we constructed at runoff database containing 1483 rainfall events collected from 107 different experimental catchments from 19 references in Korea. The collected data showed that EMCs were not correlated with storm factors whereas they showed significant differences according to the land use types. The calculated REMCs for BOD, COD, TSS, TN, and TP showed negative correlations with the GFs. However, even though the GFs of the agricultural area were concentrated in values of 80 like the green areas, the REMCs for TSS, TN, and TP were especially high. There were few differences in REMC runoff characteristics according to the GFs such as recreational facilities areas in suburbs and highways and trunk roads that connect to major roads between major cities. Except for those areas, the REMCs for BOD and COD were significantly related to the GFs. The REMCs for BOD and COD decreased when the rate of natural green area increased. On the other hand, some of the REMCs for TSS, TN, and TP were still high where the catchments encountered mixed land use patterns, especially public facility areas with bare ground and artificial grassland areas. The GF could therefore be used as a major planning indicator when establishing land use planning aimed at sustainable development with NPS management in urban areas if the weighted GF values will be improved.

  10. Experimental properties of gluon and quark jets from a point source

    International Nuclear Information System (INIS)

    Abbiendi, G.; Ackerstaff, K.; Alexander, G.

    1999-01-01

    Gluon jets are identified in hadronic Z 0 decays as all the particles in a hemisphere opposite to a hemisphere containing two tagged quark jets. Gluon jets defined in this manner are equivalent to gluon jets produced from a color singlet point source and thus correspond to the definition employed for most theoretical calculations. In a separate stage of the analysis, we select quark jets in a manner to correspond to calculations, as the particles in hemispheres of flavor tagged light quark (uds) events. We present the distributions of rapidity, scaled energy, the logarithm of the momentum, and transverse momentum with respect to the jet axes, for charged particles in these gluon and quark jets. We also examine the charged particle multiplicity distributions of the jets in restricted intervals of rapidity. For soft particles at large p T , we observe the charged particle multiplicity ratio of gluon to quark jets to be 2.29±0.09(stat.)±0.15(syst.), in agreement with the prediction that this ratio should approximately equal the ratio of QCD color factors, C A /C F =2.25. The intervals used to define soft particles and large p T for this result, p T < 3.0 GeV/c, are motivated by the predictions of the Herwig Monte Carlo multihadronic event generator. Additionally, our gluon jet data allow a sensitive test of the phenomenon of non-leading QCD terms known as color reconnection. We test the model of color reconnection implemented in the Ariadne Monte Carlo multihadronic event generator and find it to be disfavored by our data. (orig.)

  11. Stochastic Management of Non-Point Source Contamination: Joint Impact of Aquifer Heterogeneity and Well Characteristics

    Science.gov (United States)

    Henri, C. V.; Harter, T.

    2017-12-01

    Agricultural activities are recognized as the preeminent origin of non-point source (NPS) contamination of water bodies through the leakage of nitrate, salt and agrochemicals. A large fraction of world agricultural activities and therefore NPS contamination occurs over unconsolidated alluvial deposit basins offering soil composition and topography favorable to productive farming. These basins represent also important groundwater reservoirs. The over-exploitation of aquifers coupled with groundwater pollution by agriculture-related NPS contaminant has led to a rapid deterioration of the quality of these groundwater basins. The management of groundwater contamination from NPS is challenged by the inherent complexity of aquifers systems. Contaminant transport dynamics are highly uncertain due to the heterogeneity of hydraulic parameters controlling groundwater flow. Well characteristics are also key uncertain elements affecting pollutant transport and NPS management but quantifying uncertainty in NPS management under these conditions is not well documented. Our work focuses on better understanding the joint impact of aquifer heterogeneity and pumping well characteristics (extraction rate and depth) on (1) the transport of contaminants from NPS and (2) the spatio-temporal extension of the capture zone. To do so, we generate a series of geostatistically equivalent 3D heterogeneous aquifers and simulate the flow and non-reactive solute transport from NPS to extraction wells within a stochastic framework. The propagation of the uncertainty on the hydraulic conductivity field is systematically analyzed. A sensitivity analysis of the impact of extraction well characteristics (pumping rate and screen depth) is also conducted. Results highlight the significant role that heterogeneity and well characteristics plays on management metrics. We finally show that, in case of NPS contamination, the joint impact of regional longitudinal and transverse vertical hydraulic gradients and

  12. Instream Biological Assessment of NPDES Point Source Discharges at the Savannah River Site, 2000

    International Nuclear Information System (INIS)

    Specht, W.L.

    2001-01-01

    The Savannah River Site (SRS) currently has 31 NPDES outfalls that have been permitted by the South Carolina Department of Health and Environmental Control (SCDHEC) to discharge to SRS streams and the Savannah River. In order to determine the cumulative impacts of these discharges to the receiving streams, a study plan was developed to perform in-stream assessments of the fish assemblages, macroinvertebrate assemblages, and habitats of the receiving streams. These studies were designed to detect biological impacts due to point source discharges. Sampling was initially conducted between November 1997 and July 1998 and was repeated in the summer and fall of 2000. A total of 18 locations were sampled (Table 1, Figure 1). Sampling locations for fish and macroinvertebrates were generally the same. However, different locations were sampled for fish (Road A-2) and macroinvertebrates (Road C) in the lower portion of Upper Three Runs, to avoid interference with ongoing fisheries studies at Road C. Also, fish were sampled in Fourmile Branch at Road 4 rather than at Road F because the stream at Road F was too narrow and shallow to support many fish. Sampling locations and parameters are detailed in Sections 2 and 3 of this report. In general, sampling locations were selected that would permit comparisons upstream and downstream of NPDES outfalls. In instances where this approach was not feasible because effluents discharge into the headwaters of a stream, appropriate unimpacted reference were used for comparison purposes. This report summarizes the results of the sampling that was conducted in 2000 and also compares these data to the data that were collected in 1997 and 1998

  13. Reduction of gas flow into a hollow cathode ion source for a neutral beam injector

    International Nuclear Information System (INIS)

    Tanaka, S.; Akiba, M.; Arakawa, Y.; Horiike, H.; Sakuraba, J.

    1982-01-01

    Experimental studies have been made on the reduction of the gas flow rate into ion sources which utilize a hollow cathode. The electron emitter of the hollow cathode was a barium oxide impregnated porous tungsten tube. The hollow cathode was mounted to a circular or a rectangular bucket source and the following results were obtained. There was a tendency for the minimum gas flow rate for the stable source operation to decrease with increasing orifice diameter of the hollow cathode up to 10 mm. A molybdenum button with an appropriate diameter set in front of the orifice reduced the minimum gas flow rate to one half of that without button. An external magnetic field applied antiparallel to the field generated by the heater current stabilized the discharges and reduced the minimum gas flow rate to one half of that without field. Combination of the button and the antiparallel field reduced the minimum gas flow rate from the initial value (9.5 Torr 1/s) to 2.4 Torr 1/s. The reason for these effects was discussed on the basis of the theory for arc starvation

  14. Identifying and characterizing major emission point sources as a basis for geospatial distribution of mercury emissions inventories

    Science.gov (United States)

    Steenhuisen, Frits; Wilson, Simon J.

    2015-07-01

    Mercury is a global pollutant that poses threats to ecosystem and human health. Due to its global transport, mercury contamination is found in regions of the Earth that are remote from major emissions areas, including the Polar regions. Global anthropogenic emission inventories identify important sectors and industries responsible for emissions at a national level; however, to be useful for air transport modelling, more precise information on the locations of emission is required. This paper describes the methodology applied, and the results of work that was conducted to assign anthropogenic mercury emissions to point sources as part of geospatial mapping of the 2010 global anthropogenic mercury emissions inventory prepared by AMAP/UNEP. Major point-source emission sectors addressed in this work account for about 850 tonnes of the emissions included in the 2010 inventory. This work allocated more than 90% of these emissions to some 4600 identified point source locations, including significantly more point source locations in Africa, Asia, Australia and South America than had been identified during previous work to geospatially-distribute the 2005 global inventory. The results demonstrate the utility and the limitations of using existing, mainly public domain resources to accomplish this work. Assumptions necessary to make use of selected online resources are discussed, as are artefacts that can arise when these assumptions are applied to assign (national-sector) emissions estimates to point sources in various countries and regions. Notwithstanding the limitations of the available information, the value of this procedure over alternative methods commonly used to geo-spatially distribute emissions, such as use of 'proxy' datasets to represent emissions patterns, is illustrated. Improvements in information that would facilitate greater use of these methods in future work to assign emissions to point-sources are discussed. These include improvements to both national

  15. Extraction of Point Source Gamma Signals from Aerial Survey Data Taken over a Las Vegas Nevada, Residential Area

    International Nuclear Information System (INIS)

    Thane J. Hendricks

    2007-01-01

    Detection of point-source gamma signals from aerial measurements is complicated by widely varying terrestrial gamma backgrounds, since these variations frequently resemble signals from point-sources. Spectral stripping techniques have been very useful in separating man-made and natural radiation contributions which exist on Energy Research and Development Administration (ERDA) plant sites and other like facilities. However, these facilities are generally situated in desert areas or otherwise flat terrain with few man-made structures to disturb the natural background. It is of great interest to determine if the stripping technique can be successfully applied in populated areas where numerous man-made disturbances (houses, streets, yards, vehicles, etc.) exist

  16. Role of rural solid waste management in non-point source pollution control of Dianchi Lake catchments, China

    Institute of Scientific and Technical Information of China (English)

    Wenjing LU; Hongtao WANG

    2008-01-01

    In recent years, with control of the main municipal and industrial point pollution sources and implementation of cleaning for some inner pollution sources in the water body, the discharge of point source pollution decreased gradually, while non-point source pollution has become increasingly distressing in Dianchi Lake catchments. As one of the major targets in non-point source pollution control, an integrated solid waste controlling strategy combined with a technological solution and management system was proposed and implemented based on the waste disposal situation and characteristics of rural solid waste in the demonstration area. As the key technoogy in rural solid waste treatment, both centralized plantscale composting and a dispersed farmer-operated waste treating system showed promise in rendering timely benefits in efficiency, large handling capacity, high quality of the end product, as well as good economic return. Problems encountered during multi-substrates co-com-posting such as pathogens, high moisture content, asyn-chronism in the decomposition of different substrates, and low quality of the end product can all be tackled. 92.5% of solid waste was collected in the demonstration area, while the treating and recycling ratio reached 87.9%, which pre-vented 32.2 t nitrogen and 3.9 t phosphorus per year from entering the water body of Dianchi Lake after imple-mentation of the project.

  17. Comparative study of beam losses and heat loads reduction methods in MITICA beam source

    Energy Technology Data Exchange (ETDEWEB)

    Sartori, E., E-mail: emanuele.sartori@igi.cnr.it; Agostinetti, P.; Dal Bello, S.; Marcuzzi, D.; Serianni, G.; Veltri, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Sonato, P. [Consorzio RFX, Euratom-ENEA association, C.so Stati Uniti 4, 35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Via Gradenigo 6/a, 35131 Padova (Italy)

    2014-02-15

    In negative ion electrostatic accelerators a considerable fraction of extracted ions is lost by collision processes causing efficiency loss and heat deposition over the components. Stripping is proportional to the local density of gas, which is steadily injected in the plasma source; its pumping from the extraction and acceleration stages is a key functionality for the prototype of the ITER Neutral Beam Injector, and it can be simulated with the 3D code AVOCADO. Different geometric solutions were tested aiming at the reduction of the gas density. The parameter space considered is limited by constraints given by optics, aiming, voltage holding, beam uniformity, and mechanical feasibility. The guidelines of the optimization process are presented together with the proposed solutions and the results of numerical simulations.

  18. Modelling the transport of solid contaminants originated from a point source

    Science.gov (United States)

    Salgueiro, Dora V.; Conde, Daniel A. S.; Franca, Mário J.; Schleiss, Anton J.; Ferreira, Rui M. L.

    2017-04-01

    The solid phases of natural flows can comprise an important repository for contaminants in aquatic ecosystems and can propagate as turbidity currents generating a stratified environment. Contaminants can be desorbed under specific environmental conditions becoming re-suspended, with a potential impact on the aquatic biota. Forecasting the distribution of the contaminated turbidity current is thus crucial for a complete assessment of environmental exposure. In this work we validate the ability of the model STAV-2D, developed at CERIS (IST), to simulate stratified flows such as those resulting from turbidity currents in complex geometrical environments. The validation involves not only flow phenomena inherent to flows generated by density imbalance but also convective effects brought about by the complex geometry of the water basin where the current propagates. This latter aspect is of paramount importance since, in real applications, currents may propagate in semi-confined geometries in plan view, generating important convective accelerations. Velocity fields and mass distributions obtained from experiments carried out at CERIS - (IST) are used as validation data for the model. The experimental set-up comprises a point source in a rectangular basin with a wall placed perpendicularly to the outer walls. Thus generates a complex 2D flow with an advancing wave front and shocks due to the flow reflection from the walls. STAV-2D is based on the depth- and time-averaged mass and momentum equations for mixtures of water and sediment, understood as continua. It is closed in terms of flow resistance and capacity bedload discharge by a set of classic closure models and a specific high concentration formulation. The two-layer model is derived from layer-averaged Navier-Stokes equations, resulting in a system of layer-specific non-linear shallow-water equations, solved through explicit first or second-order schemes. According to the experimental data for mass distribution, the

  19. A Bayesian geostatistical approach for evaluating the uncertainty of contaminant mass discharges from point sources

    Science.gov (United States)

    Troldborg, M.; Nowak, W.; Binning, P. J.; Bjerg, P. L.

    2012-12-01

    Estimates of mass discharge (mass/time) are increasingly being used when assessing risks of groundwater contamination and designing remedial systems at contaminated sites. Mass discharge estimates are, however, prone to rather large uncertainties as they integrate uncertain spatial distributions of both concentration and groundwater flow velocities. For risk assessments or any other decisions that are being based on mass discharge estimates, it is essential to address these uncertainties. We present a novel Bayesian geostatistical approach for quantifying the uncertainty of the mass discharge across a multilevel control plane. The method decouples the flow and transport simulation and has the advantage of avoiding the heavy computational burden of three-dimensional numerical flow and transport simulation coupled with geostatistical inversion. It may therefore be of practical relevance to practitioners compared to existing methods that are either too simple or computationally demanding. The method is based on conditional geostatistical simulation and accounts for i) heterogeneity of both the flow field and the concentration distribution through Bayesian geostatistics (including the uncertainty in covariance functions), ii) measurement uncertainty, and iii) uncertain source zone geometry and transport parameters. The method generates multiple equally likely realizations of the spatial flow and concentration distribution, which all honour the measured data at the control plane. The flow realizations are generated by analytical co-simulation of the hydraulic conductivity and the hydraulic gradient across the control plane. These realizations are made consistent with measurements of both hydraulic conductivity and head at the site. An analytical macro-dispersive transport solution is employed to simulate the mean concentration distribution across the control plane, and a geostatistical model of the Box-Cox transformed concentration data is used to simulate observed

  20. Modeling non-point source pollutants in the vadose zone: Back to the basics

    Science.gov (United States)

    Corwin, Dennis L.; Letey, John, Jr.; Carrillo, Marcia L. K.

    More than ever before in the history of scientific investigation, modeling is viewed as a fundamental component of the scientific method because of the relatively recent development of the computer. No longer must the scientific investigator be confined to artificially isolated studies of individual processes that can lead to oversimplified and sometimes erroneous conceptions of larger phenomena. Computer models now enable scientists to attack problems related to open systems such as climatic change, and the assessment of environmental impacts, where the whole of the interactive processes are greater than the sum of their isolated components. Environmental assessment involves the determination of change of some constituent over time. This change can be measured in real time or predicted with a model. The advantage of prediction, like preventative medicine, is that it can be used to alter the occurrence of potentially detrimental conditions before they are manifest. The much greater efficiency of preventative, rather than remedial, efforts strongly justifies the need for an ability to accurately model environmental contaminants such as non-point source (NPS) pollutants. However, the environmental modeling advances that have accompanied computer technological development are a mixed blessing. Where once we had a plethora of discordant data without a holistic theory, now the pendulum has swung so that we suffer from a growing stockpile of models of which a significant number have never been confirmed or even attempts made to confirm them. Modeling has become an end in itself rather than a means because of limited research funding, the high cost of field studies, limitations in time and patience, difficulty in cooperative research and pressure to publish papers as quickly as possible. Modeling and experimentation should be ongoing processes that reciprocally enhance one another with sound, comprehensive experiments serving as the building blocks of models and models

  1. Point source detection using the Spherical Mexican Hat Wavelet on simulated all-sky Planck maps

    Science.gov (United States)

    Vielva, P.; Martínez-González, E.; Gallegos, J. E.; Toffolatti, L.; Sanz, J. L.

    2003-09-01

    We present an estimation of the point source (PS) catalogue that could be extracted from the forthcoming ESA Planck mission data. We have applied the Spherical Mexican Hat Wavelet (SMHW) to simulated all-sky maps that include cosmic microwave background (CMB), Galactic emission (thermal dust, free-free and synchrotron), thermal Sunyaev-Zel'dovich effect and PS emission, as well as instrumental white noise. This work is an extension of the one presented in Vielva et al. We have developed an algorithm focused on a fast local optimal scale determination, that is crucial to achieve a PS catalogue with a large number of detections and a low flux limit. An important effort has been also done to reduce the CPU time processor for spherical harmonic transformation, in order to perform the PS detection in a reasonable time. The presented algorithm is able to provide a PS catalogue above fluxes: 0.48 Jy (857 GHz), 0.49 Jy (545 GHz), 0.18 Jy (353 GHz), 0.12 Jy (217 GHz), 0.13 Jy (143 GHz), 0.16 Jy (100 GHz HFI), 0.19 Jy (100 GHz LFI), 0.24 Jy (70 GHz), 0.25 Jy (44 GHz) and 0.23 Jy (30 GHz). We detect around 27 700 PS at the highest frequency Planck channel and 2900 at the 30-GHz one. The completeness level are: 70 per cent (857 GHz), 75 per cent (545 GHz), 70 per cent (353 GHz), 80 per cent (217 GHz), 90 per cent (143 GHz), 85 per cent (100 GHz HFI), 80 per cent (100 GHz LFI), 80 per cent (70 GHz), 85 per cent (44 GHz) and 80 per cent (30 GHz). In addition, we can find several PS at different channels, allowing the study of the spectral behaviour and the physical processes acting on them. We also present the basic procedure to apply the method in maps convolved with asymmetric beams. The algorithm takes ~72 h for the most CPU time-demanding channel (857 GHz) in a Compaq HPC320 (Alpha EV68 1-GHz processor) and requires 4 GB of RAM memory; the CPU time goes as O[NRoN3/2pix log(Npix)], where Npix is the number of pixels in the map and NRo is the number of optimal scales needed.

  2. NO{sub 2} and CO nonattainment areas: a pragmatic approach to source reduction assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, S; Giugliano, M; Marzolo, F [D.I.I.A.R. - Politecnico di Milano, Milan (Italy). Environmental Section

    1996-12-31

    Many Italian large conurbations have CO and NO{sub 2} air quality standards exceeded and, consequently, require control enforcement plans to attain and maintain regulations not respected. In planning the interventions to be undertaken a fundamental issue is represented by the relationships between active emission sources and air quality, commonly described through mathematical models for evaluating the expected effects of the different reduction scenarios. This approach, relatively feasible for slightly or non reactive pollutants like CO, becomes not as easy to be applied for secondary pollutants, like NO{sub 2}, mainly for the complex photo chemical reaction systems involved in their atmospheric presence and the consequent modeling difficulties related either to the description of the system itself than to the detail in input data required. A practicable alternative in this framework relies in the utilization of statistical models for deriving, through the empirical description of the relationships between the parameters of interest, the reduction levels required for complying with the standards. Following an approach already applied with useful results to the same area, present work reports on the development and application to Milan urban area of statistical models for describing the relationships between CO and NO{sub x} annual concentration averages and the corresponding air quality standard parameters (number of standard exceedances for CO and 98th percentile of hourly concentrations for NO{sub 2}). The models are utilised upstream to simple roll-back models for the assessment of the reduction in emissions strength required for attaining air quality standards for the area. (author)

  3. NO{sub 2} and CO nonattainment areas: a pragmatic approach to source reduction assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, S.; Giugliano, M.; Marzolo, F. [D.I.I.A.R. - Politecnico di Milano, Milan (Italy). Environmental Section

    1995-12-31

    Many Italian large conurbations have CO and NO{sub 2} air quality standards exceeded and, consequently, require control enforcement plans to attain and maintain regulations not respected. In planning the interventions to be undertaken a fundamental issue is represented by the relationships between active emission sources and air quality, commonly described through mathematical models for evaluating the expected effects of the different reduction scenarios. This approach, relatively feasible for slightly or non reactive pollutants like CO, becomes not as easy to be applied for secondary pollutants, like NO{sub 2}, mainly for the complex photo chemical reaction systems involved in their atmospheric presence and the consequent modeling difficulties related either to the description of the system itself than to the detail in input data required. A practicable alternative in this framework relies in the utilization of statistical models for deriving, through the empirical description of the relationships between the parameters of interest, the reduction levels required for complying with the standards. Following an approach already applied with useful results to the same area, present work reports on the development and application to Milan urban area of statistical models for describing the relationships between CO and NO{sub x} annual concentration averages and the corresponding air quality standard parameters (number of standard exceedances for CO and 98th percentile of hourly concentrations for NO{sub 2}). The models are utilised upstream to simple roll-back models for the assessment of the reduction in emissions strength required for attaining air quality standards for the area. (author)

  4. [Multiple time scales analysis of spatial differentiation characteristics of non-point source nitrogen loss within watershed].

    Science.gov (United States)

    Liu, Mei-bing; Chen, Xing-wei; Chen, Ying

    2015-07-01

    Identification of the critical source areas of non-point source pollution is an important means to control the non-point source pollution within the watershed. In order to further reveal the impact of multiple time scales on the spatial differentiation characteristics of non-point source nitrogen loss, a SWAT model of Shanmei Reservoir watershed was developed. Based on the simulation of total nitrogen (TN) loss intensity of all 38 subbasins, spatial distribution characteristics of nitrogen loss and critical source areas were analyzed at three time scales of yearly average, monthly average and rainstorms flood process, respectively. Furthermore, multiple linear correlation analysis was conducted to analyze the contribution of natural environment and anthropogenic disturbance on nitrogen loss. The results showed that there were significant spatial differences of TN loss in Shanmei Reservoir watershed at different time scales, and the spatial differentiation degree of nitrogen loss was in the order of monthly average > yearly average > rainstorms flood process. TN loss load mainly came from upland Taoxi subbasin, which was identified as the critical source area. At different time scales, land use types (such as farmland and forest) were always the dominant factor affecting the spatial distribution of nitrogen loss, while the effect of precipitation and runoff on the nitrogen loss was only taken in no fertilization month and several processes of storm flood at no fertilization date. This was mainly due to the significant spatial variation of land use and fertilization, as well as the low spatial variability of precipitation and runoff.

  5. Taming the beast : Free and open-source massive point cloud web visualization

    NARCIS (Netherlands)

    Martinez-Rubi, O.; Verhoeven, S.; Van Meersbergen, M.; Schûtz, M.; Van Oosterom, P.; Gonçalves, R.; Tijssen, T.

    2015-01-01

    Powered by WebGL, some renderers have recently become available for the visualization of point cloud data over the web, for example Plasio or Potree. We have extended Potree to be able to visualize massive point clouds and we have successfully used it with the second national Lidar survey of the

  6. Contaminant dispersion prediction and source estimation with integrated Gaussian-machine learning network model for point source emission in atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Denglong [Fuli School of Food Equipment Engineering and Science, Xi’an Jiaotong University, No.28 Xianning West Road, Xi’an 710049 (China); Zhang, Zaoxiao, E-mail: zhangzx@mail.xjtu.edu.cn [State Key Laboratory of Multiphase Flow in Power Engineering, Xi’an Jiaotong University, No.28 Xianning West Road, Xi’an 710049 (China); School of Chemical Engineering and Technology, Xi’an Jiaotong University, No.28 Xianning West Road, Xi’an 710049 (China)

    2016-07-05

    Highlights: • The intelligent network models were built to predict contaminant gas concentrations. • The improved network models coupled with Gaussian dispersion model were presented. • New model has high efficiency and accuracy for concentration prediction. • New model were applied to indentify the leakage source with satisfied results. - Abstract: Gas dispersion model is important for predicting the gas concentrations when contaminant gas leakage occurs. Intelligent network models such as radial basis function (RBF), back propagation (BP) neural network and support vector machine (SVM) model can be used for gas dispersion prediction. However, the prediction results from these network models with too many inputs based on original monitoring parameters are not in good agreement with the experimental data. Then, a new series of machine learning algorithms (MLA) models combined classic Gaussian model with MLA algorithm has been presented. The prediction results from new models are improved greatly. Among these models, Gaussian-SVM model performs best and its computation time is close to that of classic Gaussian dispersion model. Finally, Gaussian-MLA models were applied to identifying the emission source parameters with the particle swarm optimization (PSO) method. The estimation performance of PSO with Gaussian-MLA is better than that with Gaussian, Lagrangian stochastic (LS) dispersion model and network models based on original monitoring parameters. Hence, the new prediction model based on Gaussian-MLA is potentially a good method to predict contaminant gas dispersion as well as a good forward model in emission source parameters identification problem.

  7. Contaminant dispersion prediction and source estimation with integrated Gaussian-machine learning network model for point source emission in atmosphere

    International Nuclear Information System (INIS)

    Ma, Denglong; Zhang, Zaoxiao

    2016-01-01

    Highlights: • The intelligent network models were built to predict contaminant gas concentrations. • The improved network models coupled with Gaussian dispersion model were presented. • New model has high efficiency and accuracy for concentration prediction. • New model were applied to indentify the leakage source with satisfied results. - Abstract: Gas dispersion model is important for predicting the gas concentrations when contaminant gas leakage occurs. Intelligent network models such as radial basis function (RBF), back propagation (BP) neural network and support vector machine (SVM) model can be used for gas dispersion prediction. However, the prediction results from these network models with too many inputs based on original monitoring parameters are not in good agreement with the experimental data. Then, a new series of machine learning algorithms (MLA) models combined classic Gaussian model with MLA algorithm has been presented. The prediction results from new models are improved greatly. Among these models, Gaussian-SVM model performs best and its computation time is close to that of classic Gaussian dispersion model. Finally, Gaussian-MLA models were applied to identifying the emission source parameters with the particle swarm optimization (PSO) method. The estimation performance of PSO with Gaussian-MLA is better than that with Gaussian, Lagrangian stochastic (LS) dispersion model and network models based on original monitoring parameters. Hence, the new prediction model based on Gaussian-MLA is potentially a good method to predict contaminant gas dispersion as well as a good forward model in emission source parameters identification problem.

  8. Validation of novel calibration scheme with traceable point-like (22)Na sources on six types of PET scanners.

    Science.gov (United States)

    Hasegawa, Tomoyuki; Oda, Keiichi; Wada, Yasuhiro; Sasaki, Toshiaki; Sato, Yasushi; Yamada, Takahiro; Matsumoto, Mikio; Murayama, Hideo; Kikuchi, Kei; Miyatake, Hiroki; Abe, Yutaka; Miwa, Kenta; Akimoto, Kenta; Wagatsuma, Kei

    2013-05-01

    To improve the reliability and convenience of the calibration procedure of positron emission tomography (PET) scanners, we have been developing a novel calibration path based on traceable point-like sources. When using (22)Na sources, special care should be taken to avoid the effects of 1.275-MeV γ rays accompanying β (+) decays. The purpose of this study is to validate this new calibration scheme with traceable point-like (22)Na sources on various types of PET scanners. Traceable point-like (22)Na sources with a spherical absorber design that assures uniform angular distribution of the emitted annihilation photons were used. The tested PET scanners included a clinical whole-body PET scanner, four types of clinical PET/CT scanners from different manufacturers, and a small-animal PET scanner. The region of interest (ROI) diameter dependence of ROI values was represented with a fitting function, which was assumed to consist of a recovery part due to spatial resolution and a quadratic background part originating from the scattered γ rays. The observed ROI radius dependence was well represented with the assumed fitting function (R (2) > 0.994). The calibration factors determined using the point-like sources were consistent with those by the standard cross-calibration method within an uncertainty of ±4 %, which was reasonable considering the uncertainty in the standard cross-calibration method. This novel calibration scheme based on the use of traceable (22)Na point-like sources was successfully validated for six types of commercial PET scanners.

  9. A modified likelihood-method to search for point-sources in the diffuse astrophysical neutrino-flux in IceCube

    Energy Technology Data Exchange (ETDEWEB)

    Reimann, Rene; Haack, Christian; Leuermann, Martin; Raedel, Leif; Schoenen, Sebastian; Schimp, Michael; Wiebusch, Christopher [III. Physikalisches Institut, RWTH Aachen (Germany); Collaboration: IceCube-Collaboration

    2015-07-01

    IceCube, a cubic-kilometer sized neutrino detector at the geographical South Pole, has recently measured a flux of high-energy astrophysical neutrinos. Although this flux has now been observed in multiple analyses, no point sources or source classes could be identified yet. Standard point source searches test many points in the sky for a point source of astrophysical neutrinos individually and therefore produce many trials. Our approach is to additionally use the measured diffuse spectrum to constrain the number of possible point sources and their properties. Initial studies of the method performance are shown.

  10. Design and evaluation of aircraft heat source systems for use with high-freezing point fuels

    Science.gov (United States)

    Pasion, A. J.

    1979-01-01

    The objectives were the design, performance and economic analyses of practical aircraft fuel heating systems that would permit the use of high freezing-point fuels on long-range aircraft. Two hypothetical hydrocarbon fuels with freezing points of -29 C and -18 C were used to represent the variation from current day jet fuels. A Boeing 747-200 with JT9D-7/7A engines was used as the baseline aircraft. A 9300 Km mission was used as the mission length from which the heat requirements to maintain the fuel above its freezing point was based.

  11. Seeing the Point: Using Visual Sources to Understand the Arguments for Women's Suffrage

    Science.gov (United States)

    Card, Jane

    2011-01-01

    Visual sources, Jane Card argues, are a powerful resource for historical learning but using them in the classroom requires careful thought and planning. Card here shares how she has used visual source material in order to teach her students about the women's suffrage movement. In particular, Card shows how a chain of questions that moves from the…

  12. Improved Point-source Detection in Crowded Fields Using Probabilistic Cataloging

    Science.gov (United States)

    Portillo, Stephen K. N.; Lee, Benjamin C. G.; Daylan, Tansu; Finkbeiner, Douglas P.

    2017-10-01

    Cataloging is challenging in crowded fields because sources are extremely covariant with their neighbors and blending makes even the number of sources ambiguous. We present the first optical probabilistic catalog, cataloging a crowded (˜0.1 sources per pixel brighter than 22nd mag in F606W) Sloan Digital Sky Survey r-band image from M2. Probabilistic cataloging returns an ensemble of catalogs inferred from the image and thus can capture source-source covariance and deblending ambiguities. By comparing to a traditional catalog of the same image and a Hubble Space Telescope catalog of the same region, we show that our catalog ensemble better recovers sources from the image. It goes more than a magnitude deeper than the traditional catalog while having a lower false-discovery rate brighter than 20th mag. We also present an algorithm for reducing this catalog ensemble to a condensed catalog that is similar to a traditional catalog, except that it explicitly marginalizes over source-source covariances and nuisance parameters. We show that this condensed catalog has a similar completeness and false-discovery rate to the catalog ensemble. Future telescopes will be more sensitive, and thus more of their images will be crowded. Probabilistic cataloging performs better than existing software in crowded fields and so should be considered when creating photometric pipelines in the Large Synoptic Survey Telescope era.

  13. Risk-based prioritisation of point sources through assessment of the impact on a water supply

    DEFF Research Database (Denmark)

    Overheu, Niels D.; Tuxen, Nina; Troldborg, Mads

    2011-01-01

    vulnerability mapping, site-specific mass flux estimates on a local scale from all the sources, and 3-D catchment-scale fate and transport modelling. It handles sources at various knowledge levels and accounts for uncertainties. The tool estimates the impacts on the water supply in the catchment and provides...

  14. Polarized point sources in the LOFAR Two-meter Sky Survey: A preliminary catalog

    Science.gov (United States)

    Van Eck, C. L.; Haverkorn, M.; Alves, M. I. R.; Beck, R.; Best, P.; Carretti, E.; Chyży, K. T.; Farnes, J. S.; Ferrière, K.; Hardcastle, M. J.; Heald, G.; Horellou, C.; Iacobelli, M.; Jelić, V.; Mulcahy, D. D.; O'Sullivan, S. P.; Polderman, I. M.; Reich, W.; Riseley, C. J.; Röttgering, H.; Schnitzeler, D. H. F. M.; Shimwell, T. W.; Vacca, V.; Vink, J.; White, G. J.

    2018-06-01

    The polarization properties of radio sources at very low frequencies (right ascension, 45°-57° declination, 570 square degrees). We have produced a catalog of 92 polarized radio sources at 150 MHz at 4.'3 resolution and 1 mJy rms sensitivity, which is the largest catalog of polarized sources at such low frequencies. We estimate a lower limit to the polarized source surface density at 150 MHz, with our resolution and sensitivity, of 1 source per 6.2 square degrees. We find that our Faraday depth measurements are in agreement with previous measurements and have significantly smaller errors. Most of our sources show significant depolarization compared to 1.4 GHz, but there is a small population of sources with low depolarization indicating that their polarized emission is highly localized in Faraday depth. We predict that an extension of this work to the full LOTSS data would detect at least 3400 polarized sources using the same methods, and probably considerably more with improved data processing.

  15. Reduction of PM emissions from specific sources reflected on key components concentrations of ambient PM10

    Science.gov (United States)

    Minguillon, M. C.; Querol, X.; Monfort, E.; Alastuey, A.; Escrig, A.; Celades, I.; Miro, J. V.

    2009-04-01

    The relationship between specific particulate emission control and ambient levels of some PM10 components (Zn, As, Pb, Cs, Tl) was evaluated. To this end, the industrial area of Castellón (Eastern Spain) was selected, where around 40% of the EU glazed ceramic tiles and a high proportion of EU ceramic frits (middle product for the manufacture of ceramic glaze) are produced. The PM10 emissions from the ceramic processes were calculated over the period 2000 to 2007 taking into account the degree of implementation of corrective measures throughout the study period. Abatement systems (mainly bag filters) were implemented in the majority of the fusion kilns for frit manufacture in the area as a result of the application of the Directive 1996/61/CE, leading to a marked decrease in PM10 emissions. On the other hand, ambient PM10 sampling was carried out from April 2002 to July 2008 at three urban sites and one suburban site of the area and a complete chemical analysis was made for about 35 % of the collected samples, by means of different techniques (ICP-AES, ICP-MS, Ion Chromatography, selective electrode and elemental analyser). The series of chemical composition of PM10 allowed us to apply a source contribution model (Principal Component Analysis), followed by a multilinear regression analysis, so that PM10 sources were identified and their contribution to bulk ambient PM10 was quantified on a daily basis, as well as the contribution to bulk ambient concentrations of the identified key components (Zn, As, Pb, Cs, Tl). The contribution of the sources identified as the manufacture and use of ceramic glaze components, including the manufacture of ceramic frits, accounted for more than 65, 75, 58, 53, and 53% of ambient Zn, As, Pb, Cs and Tl levels, respectively (with the exception of Tl contribution at one of the sites). The important emission reductions of these sources during the study period had an impact on ambient key components levels, such that there was a high

  16. Morphology, chemistry and distribution of neoformed spherulites in agricultural land affected by metallurgical point-source pollution

    NARCIS (Netherlands)

    Leguedois, S.; Oort, van F.; Jongmans, A.G.; Chevalier, P.

    2004-01-01

    Metal distribution patterns in superficial soil horizons of agricultural land affected by metallurgical point-source pollution were studied using optical and electron microscopy, synchrotron radiation and spectroscopy analyses. The site is located in northern France, at the center of a former entry

  17. The Central Point Source in G76.9++1.0 V. R. Marthi1,∗ , J. N. ...

    Indian Academy of Sciences (India)

    Astr. (2011) 32, 451–455 c Indian Academy of Sciences. The Central Point Source in G76.9++1.0. V. R. Marthi1,∗. , J. N. Chengalur1, Y. Gupta1 ... emission has indeed been seen at 2 GHz with the Green Bank Telescope. (GBT), establishing the fact that scattering is responsible for its non- detection at low radio frequencies.

  18. Effects of pointing compared with naming and observing during encoding on item and source memory in young and older adults

    NARCIS (Netherlands)

    Ouwehand, Kim; Gog, Tamara van; Paas, Fred

    2016-01-01

    Research showed that source memory functioning declines with ageing. Evidence suggests that encoding visual stimuli with manual pointing in addition to visual observation can have a positive effect on spatial memory compared with visual observation only. The present study investigated whether

  19. Point Sources of Emerging Contaminants Along the Colorado River Basin: Impact on Water Use and Reuse in the Arid Southwest

    Science.gov (United States)

    Emerging contaminants (ECs) (e.g., pharmaceuticals, illicit drugs, personal care products) have been detected in waters across the United States. The objective of this study was to evaluate point sources of ECs along the Colorado River, from the headwaters in Colorado to the Gulf...

  20. Estimation of Multiple Point Sources for Linear Fractional Order Systems Using Modulating Functions

    KAUST Repository

    Belkhatir, Zehor; Laleg-Kirati, Taous-Meriem

    2017-01-01

    This paper proposes an estimation algorithm for the characterization of multiple point inputs for linear fractional order systems. First, using polynomial modulating functions method and a suitable change of variables the problem of estimating

  1. The Potential for Electrofuels Production in Sweden Utilizing Fossil and Biogenic CO{sub 2} Point Sources

    Energy Technology Data Exchange (ETDEWEB)

    Hansson, Julia, E-mail: julia.hansson@ivl.se [Climate and Sustainable Cities, IVL Swedish Environmental Research Institute, Stockholm (Sweden); Division of Physical Resource Theory, Department of Energy and Environment, Chalmers University of Technology, Göteborg (Sweden); Hackl, Roman [Climate and Sustainable Cities, IVL Swedish Environmental Research Institute, Stockholm (Sweden); Taljegard, Maria [Division of Energy Technology, Department of Energy and Environment, Chalmers University of Technology, Göteborg (Sweden); Brynolf, Selma; Grahn, Maria [Division of Physical Resource Theory, Department of Energy and Environment, Chalmers University of Technology, Göteborg (Sweden)

    2017-03-13

    This paper maps, categorizes, and quantifies all major point sources of carbon dioxide (CO{sub 2}) emissions from industrial and combustion processes in Sweden. The paper also estimates the Swedish technical potential for electrofuels (power-to-gas/fuels) based on carbon capture and utilization. With our bottom-up approach using European databases, we find that Sweden emits approximately 50 million metric tons of CO{sub 2} per year from different types of point sources, with 65% (or about 32 million tons) from biogenic sources. The major sources are the pulp and paper industry (46%), heat and power production (23%), and waste treatment and incineration (8%). Most of the CO{sub 2} is emitted at low concentrations (<15%) from sources in the southern part of Sweden where power demand generally exceeds in-region supply. The potentially recoverable emissions from all the included point sources amount to 45 million tons. If all the recoverable CO{sub 2} were used to produce electrofuels, the yield would correspond to 2–3 times the current Swedish demand for transportation fuels. The electricity required would correspond to about 3 times the current Swedish electricity supply. The current relatively few emission sources with high concentrations of CO{sub 2} (>90%, biofuel operations) would yield electrofuels corresponding to approximately 2% of the current demand for transportation fuels (corresponding to 1.5–2 TWh/year). In a 2030 scenario with large-scale biofuels operations based on lignocellulosic feedstocks, the potential for electrofuels production from high-concentration sources increases to 8–11 TWh/year. Finally, renewable electricity and production costs, rather than CO{sub 2} supply, limit the potential for production of electrofuels in Sweden.

  2. The 100 strongest radio point sources in the field of the Large Magellanic Cloud at 1.4 GHz

    Directory of Open Access Journals (Sweden)

    Payne J.L.

    2009-01-01

    Full Text Available We present the 100 strongest 1.4 GHz point sources from a new mosaic image in the direction of the Large Magellanic Cloud (LMC. The observations making up the mosaic were made using Australia Telescope Compact Array (ATCA over a ten year period and were combined with Parkes single dish data at 1.4 GHz to complete the image for short spacing. An initial list of co-identifications within 1000 at 0.843, 4.8 and 8.6 GHz consisted of 2682 sources. Elimination of extended objects and artifact noise allowed the creation of a refined list containing 1988 point sources. Most of these are presumed to be background objects seen through the LMC; a small portion may represent compact H ii regions, young SNRs and radio planetary nebulae. For the 1988 point sources we find a preliminary average spectral index (α of -0.53 and present a 1.4 GHz image showing source location in the direction of the LMC.

  3. The 100 Strongest Radio Point Sources in the Field of the Large Magellanic Cloud at 1.4 GHz

    Directory of Open Access Journals (Sweden)

    Payne, J. L.

    2009-06-01

    Full Text Available We present the 100 strongest 1.4~GHz point sources from a new mosaicimage in the direction of the Large Magellanic Cloud (LMC. The observationsmaking up the mosaic were made using Australia Telescope Compact Array (ATCAover a ten year period and were combined with Parkes single dish data at 1.4 GHz to complete the image for short spacing. An initial list of co-identifications within 10arcsec at 0.843, 4.8 and 8.6 GHz consisted of 2682 sources. Elimination of extended objects and artifact noise allowed the creation of a refined list containing 1988 point sources. Most of these are presumed to be background objects seen through the LMC; a small portion may represent compact HII regions, young SNRs and radio planetary nebulae. For the 1988 point sources we find a preliminary average spectral index ($alpha$ of -0.53 and present a 1.4 GHz image showing source locationin the direction of the LMC.

  4. The Development and Application of Spatiotemporal Metrics for the Characterization of Point Source FFCO2 Emissions and Dispersion

    Science.gov (United States)

    Roten, D.; Hogue, S.; Spell, P.; Marland, E.; Marland, G.

    2017-12-01

    There is an increasing role for high resolution, CO2 emissions inventories across multiple arenas. The breadth of the applicability of high-resolution data is apparent from their use in atmospheric CO2 modeling, their potential for validation of space-based atmospheric CO2 remote-sensing, and the development of climate change policy. This work focuses on increasing our understanding of the uncertainty in these inventories and the implications on their downstream use. The industrial point sources of emissions (power generating stations, cement manufacturing plants, paper mills, etc.) used in the creation of these inventories often have robust emissions characteristics, beyond just their geographic location. Physical parameters of the emission sources such as number of exhaust stacks, stack heights, stack diameters, exhaust temperatures, and exhaust velocities, as well as temporal variability and climatic influences can be important in characterizing emissions. Emissions from large point sources can behave much differently than emissions from areal sources such as automobiles. For many applications geographic location is not an adequate characterization of emissions. This work demonstrates the sensitivities of atmospheric models to the physical parameters of large point sources and provides a methodology for quantifying parameter impacts at multiple locations across the United States. The sensitivities highlight the importance of location and timing and help to highlight potential aspects that can guide efforts to reduce uncertainty in emissions inventories and increase the utility of the models.

  5. Reducing plant radiation fields by source term reduction - tracking cobalt and antimony to their sources at Gentilly-2

    International Nuclear Information System (INIS)

    Gauthier, P.; Guzonas, D.A.

    2006-01-01

    the same specifications at Gentilly-2 as at other CANDU 6 plants. Consequently, the task group revisited operating and maintenance practices, going back through station operating history to identify operational practices that could have lead to increased 59 Co release and/or 60 Co production. The focus rapidly moved to the fuel handling system, as it had long been suspected, but never proven, that the Stellite ram balls were a major source of 59 Co; the fuelling machines provide a direct route for the introduction of corrosion or wear products into the reactor core. Data on the gamma fields measured in the fuelling machine D 2 O supply room from 1995 to the present were reviewed. Water samples were taken and chemically analysed. The results confirmed the presence of 59 Co, probably generated by the wear and corrosion of the Stellite ram balls, and also confirmed the presence of antimony in the system. As part of the task group program, γ-spectrometry was performed in the course of a refuelling cycle. The results showed that variations in the general radiation fields observed in the fuelling machine D 2 O supply room resulted from variations of the 122 Sb and 124 Sb concentrations in the process water. The presence of 122 Sb (t 1/2 3.2 d) suggested that the antimony was recently released from the reactor core. 60 Co was also detected but the level was constant; 59 Co from the ram balls is invisible to γ-spectrometry before it is activated to 60 Co. Remedial actions were implemented in mid-July, 2004. Shortly after, a significant reduction in the radiation fields in the Gentilly-2 fuelling machine D2 O supply room was confirmed. During an unplanned outage in December 2004, a decrease in fields, in particular those due to 60 Co and radioantimony, was found at the reactor face. Activity monitoring scheduled for the 2005 annual outage should confirm if the source of the abnormally high fields has finally been identified. This presentation will describe the task force

  6. Discovery of a point-like very-high-energy gamma-ray source in Monoceros

    International Nuclear Information System (INIS)

    Aharonian, F.A.; Benbow, W.; Berge, D.; Bernlohr, K.; Bolz, O.; Braun, I.; Buhler, R.; Carrigan, S.; Costamante, L.; Domainko, W.; Egberts, K.; Forster, A.; Funk, S.; Hauser, D.; Hermann, G.; Hinton, J.A.; Hofmann, W.; Hoppe, S.; Khelifi, B.; Kosack, K.; Masterson, C.; Panter, M.; Rowell, G.; van Eldik, C.; Volk, H.J.; Akhperjanian, A.G.; Sahakian, V.; Bazer-Bachi, A.R.; Borrel, V.; Marcowith, A.; Olive, J.P.; Beilicke, M.; Cornils, R.; Heinzelmann, G.; Raue, M.; Ripken, J.; Bernlohr, K.; Funk, Seb.; Fussling, M.; Kerschhaggl, M.; Lohse, T.; Schlenker, S.; Schwanke, U.; Boisson, C.; Martin, J.M.; Sol, H.; Brion, E.; Glicenstein, J.F.; Goret, P.; Moulin, E.; Rolland, L.

    2007-01-01

    Aims. The complex Monoceros Loop SNR/Rosette Nebula region contains several potential sources of very-high-energy (VHE) γ-ray emission and two as yet unidentified high-energy EGRET sources. Sensitive VHE observations are required to probe acceleration processes in this region. Methods. The HESS telescope array has been used to search for very high-energy gamma-ray sources in this region. CO data from the NANTEN telescope were used to map the molecular clouds in the region, which could act as target material for γ-ray production via hadronic interactions. Results. We announce the discovery of a new γ-ray source, HESS J0632+057, located close to the rim of the Monoceros SNR. This source is unresolved by HESS and has no clear counterpart at other wavelengths but is possibly associated with the weak X-ray source 1RXS J063258.3+054857, the Be-star MWC148 and/or the lower energy γ-ray source 3EGJ0634+0521. No evidence for an associated molecular cloud was found in the CO data. (authors)

  7. Impact of Point and Non-point Source Pollution on Coral Reef Ecosystems In Mamala Bay, Oahu, Hawaii based on Water Quality Measurements and Benthic Surveys in 1993-1994 (NODC Accession 0001172)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The effects of both point and non-point sources of pollution on coral reef ecosystems in Mamala Bay were studied at three levels of biological organization; the...

  8. Comparison of point-source pollutant loadings to soil and groundwater for 72 chemical substances.

    Science.gov (United States)

    Yu, Soonyoung; Hwang, Sang-Il; Yun, Seong-Taek; Chae, Gitak; Lee, Dongsu; Kim, Ki-Eun

    2017-11-01

    Fate and transport of 72 chemicals in soil and groundwater were assessed by using a multiphase compositional model (CompFlow Bio) because some of the chemicals are non-aqueous phase liquids or solids in the original form. One metric ton of chemicals were assumed to leak in a stylized facility. Scenarios of both surface spills and subsurface leaks were considered. Simulation results showed that the fate and transport of chemicals above the water table affected the fate and transport of chemicals below the water table, and vice versa. Surface spill scenarios caused much less concentrations than subsurface leak scenarios because leaching amounts into the subsurface environment were small (at most 6% of the 1 t spill for methylamine). Then, simulation results were applied to assess point-source pollutant loadings to soil and groundwater above and below the water table, respectively, by multiplying concentrations, impact areas, and durations. These three components correspond to the intensity of contamination, mobility, and persistency in the assessment of pollutant loading, respectively. Assessment results showed that the pollutant loadings in soil and groundwater were linearly related (r 2  = 0.64). The pollutant loadings were negatively related with zero-order and first-order decay rates in both soil (r = - 0.5 and - 0.6, respectively) and groundwater (- 1.0 and - 0.8, respectively). In addition, this study scientifically defended that the soil partitioning coefficient (K d ) significantly affected the pollutant loadings in soil (r = 0.6) and the maximum masses in groundwater (r = - 0.9). However, K d was not a representative factor for chemical transportability unlike the expectation in chemical ranking systems of soil and groundwater pollutants. The pollutant loadings estimated using a physics-based hydrogeological model provided a more rational ranking for exposure assessment, compared to the summation of persistency and transportability scores in

  9. Optimizing the calculation of point source count-centroid in pixel size measurement

    International Nuclear Information System (INIS)

    Zhou Luyi; Kuang Anren; Su Xianyu

    2004-01-01

    Pixel size is an important parameter of gamma camera and SPECT. A number of methods are used for its accurate measurement. In the original count-centroid method, where the image of a point source (PS) is acquired and its count-centroid calculated to represent PS position in the image, background counts are inevitable. Thus the measured count-centroid (X m ) is an approximation of the true count-centroid (X p ) of the PS, i.e. X m =X p + (X b -X p )/(1+R p /R b ), where Rp is the net counting rate of the PS, X b the background count-centroid and Rb the background counting. To get accurate measurement, R p must be very big, which is unpractical, resulting in the variation of measured pixel size. R p -independent calculation of PS count-centroid is desired. Methods: The proposed method attempted to eliminate the effect of the term (X b -X p )/(1 + R p /R b ) by bringing X b closer to X p and by reducing R b . In the acquired PS image, a circular ROI was generated to enclose the PS, the pixel with the maximum count being the center of the ROI. To choose the diameter (D) of the ROI, a Gaussian count distribution was assumed for the PS, accordingly, K=1-(0.5) D/R percent of the total PS counts was in the ROI, R being the full width at half maximum of the PS count distribution. D was set to be 6*R to enclose most (K=98.4%) of the PS counts. The count-centroid of the ROI was calculated to represent X p . The proposed method was tested in measuring the pixel size of a well-tuned SPECT, whose pixel size was estimated to be 3.02 mm according to its mechanical and electronic setting (128 x 128 matrix, 387 mm UFOV, ZOOM=1). For comparison, the original method, which was use in the former versions of some commercial SPECT software, was also tested. 12 PSs were prepared and their image acquired and stored. The net counting rate of the PSs increased from 10 cps to 1183 cps. Results: Using the proposed method, the measured pixel size (in mm) varied only between 3.00 and 3.01 (mean

  10. Optimizing the calculation of point source count-centroid in pixel size measurement

    International Nuclear Information System (INIS)

    Zhou Luyi; Kuang Anren; Su Xianyu

    2004-01-01

    Purpose: Pixel size is an important parameter of gamma camera and SPECT. A number of Methods are used for its accurate measurement. In the original count-centroid method, where the image of a point source(PS) is acquired and its count-centroid calculated to represent PS position in the image, background counts are inevitable. Thus the measured count-centroid (Xm) is an approximation of the true count-centroid (Xp) of the PS, i.e. Xm=Xp+(Xb-Xp)/(1+Rp/Rb), where Rp is the net counting rate of the PS, Xb the background count-centroid and Rb the background counting rate. To get accurate measurement, Rp must be very big, which is unpractical, resulting in the variation of measured pixel size. Rp-independent calculation of PS count-centroid is desired. Methods: The proposed method attempted to eliminate the effect of the term (Xb-Xp)/(1+Rp/Rb) by bringing Xb closer to Xp and by reducing Rb. In the acquired PS image, a circular ROI was generated to enclose the PS, the pixel with the maximum count being the center of the ROI. To choose the diameter (D) of the ROI, a Gaussian count distribution was assumed for the PS, accordingly, K=I-(0.5)D/R percent of the total PS counts was in the ROI, R being the full width at half maximum of the PS count distribution. D was set to be 6*R to enclose most (K=98.4%) of the PS counts. The count-centroid of the ROI was calculated to represent Xp. The proposed method was tested in measuring the pixel size of a well-tuned SPECT, whose pixel size was estimated to be 3.02 mm according to its mechanical and electronic setting (128*128 matrix, 387 mm UFOV, ZOOM=1). For comparison, the original method, which was use in the former versions of some commercial SPECT software, was also tested. 12 PSs were prepared and their image acquired and stored. The net counting rate of the PSs increased from 10cps to 1183cps. Results: Using the proposed method, the measured pixel size (in mm) varied only between 3.00 and 3.01( mean= 3.01±0.00) as Rp increased

  11. A method to analyze “source–sink” structure of non-point source pollution based on remote sensing technology

    International Nuclear Information System (INIS)

    Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui

    2013-01-01

    With the purpose of providing scientific basis for environmental planning about non-point source pollution prevention and control, and improving the pollution regulating efficiency, this paper established the Grid Landscape Contrast Index based on Location-weighted Landscape Contrast Index according to the “source–sink” theory. The spatial distribution of non-point source pollution caused by Jiulongjiang Estuary could be worked out by utilizing high resolution remote sensing images. The results showed that, the area of “source” of nitrogen and phosphorus in Jiulongjiang Estuary was 534.42 km 2 in 2008, and the “sink” was 172.06 km 2 . The “source” of non-point source pollution was distributed mainly over Xiamen island, most of Haicang, east of Jiaomei and river bank of Gangwei and Shima; and the “sink” was distributed over southwest of Xiamen island and west of Shima. Generally speaking, the intensity of “source” gets weaker along with the distance from the seas boundary increase, while “sink” gets stronger. -- Highlights: •We built an index to study the “source–sink” structure of NSP in a space scale. •The Index was applied in Jiulongjiang estuary and got a well result. •The study is beneficial to discern the high load area of non-point source pollution. -- “Source–Sink” Structure of non-point source nitrogen and phosphorus pollution in Jiulongjiang estuary in China was worked out by the Grid Landscape Contrast Index

  12. Time dependence of the field energy densities surrounding sources: Application to scalar mesons near point sources and to electromagnetic fields near molecules

    International Nuclear Information System (INIS)

    Persico, F.; Power, E.A.

    1987-01-01

    The time dependence of the dressing-undressing process, i.e., the acquiring or losing by a source of a boson field intensity and hence of a field energy density in its neighborhood, is considered by examining some simple soluble models. First, the loss of the virtual field is followed in time when a point source is suddenly decoupled from a neutral scalar meson field. Second, an initially bare point source acquires a virtual meson cloud as the coupling is switched on. The third example is that of an initially bare molecule interacting with the vacuum of the electromagnetic field to acquire a virtual photon cloud. In all three cases the dressing-undressing is shown to take place within an expanding sphere of radius r = ct centered at the source. At each point in space the energy density tends, for large times, to that of the ground state of the total system. Differences in the time dependence of the dressing between the massive scalar field and the massless electromagnetic field are discussed. The results are also briefly discussed in the light of Feinberg's ideas on the nature of half-dressed states in quantum field theory

  13. Solute transport with periodic input point source in one-dimensional ...

    African Journals Online (AJOL)

    JOY

    groundwater flow velocity is considered proportional to multiple of temporal function and ζ th ... One-dimensional solute transport through porous media with or without .... solute free. ... the periodic concentration at source of the boundary i.e.,. 0.

  14. The effect of multimicrophone noise reduction systems on sound source localization by users of binaural hearing aids.

    Science.gov (United States)

    Van den Bogaert, Tim; Doclo, Simon; Wouters, Jan; Moonen, Marc

    2008-07-01

    This paper evaluates the influence of three multimicrophone noise reduction algorithms on the ability to localize sound sources. Two recently developed noise reduction techniques for binaural hearing aids were evaluated, namely, the binaural multichannel Wiener filter (MWF) and the binaural multichannel Wiener filter with partial noise estimate (MWF-N), together with a dual-monaural adaptive directional microphone (ADM), which is a widely used noise reduction approach in commercial hearing aids. The influence of the different algorithms on perceived sound source localization and their noise reduction performance was evaluated. It is shown that noise reduction algorithms can have a large influence on localization and that (a) the ADM only preserves localization in the forward direction over azimuths where limited or no noise reduction is obtained; (b) the MWF preserves localization of the target speech component but may distort localization of the noise component. The latter is dependent on signal-to-noise ratio and masking effects; (c) the MWF-N enables correct localization of both the speech and the noise components; (d) the statistical Wiener filter approach introduces a better combination of sound source localization and noise reduction performance than the ADM approach.

  15. A 24 μm point source catalog of the galactic plane from Spitzer/MIPSGAL

    Energy Technology Data Exchange (ETDEWEB)

    Gutermuth, Robert A.; Heyer, Mark [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States)

    2015-02-01

    In this contribution, we describe the applied methods to construct a 24 μm based point source catalog derived from the image data of the MIPSGAL 24 μm Galactic Plane Survey and the corresponding data products. The high quality catalog product contains 933,818 sources, with a total of 1,353,228 in the full archive catalog. The source tables include positional and photometric information derived from the 24 μm images, source quality and confusion flags, and counterpart photometry from matched 2MASS, GLIMPSE, and WISE point sources. Completeness decay data cubes are constructed at 1′ angular resolution that describe the varying background levels over the MIPSGAL field and the ability to extract sources of a given magnitude from this background. The completeness decay cubes are included in the set of data products. We present the results of our efforts to verify the astrometric and photometric calibration of the catalog, and present several analyses of minor anomalies in these measurements to justify adopted mitigation strategies.

  16. An Analysis of Air Pollution in Makkah - a View Point of Source Identification

    Directory of Open Access Journals (Sweden)

    Turki M. Habeebullah

    2013-07-01

    Full Text Available Makkah is one of the busiest cities in Saudi Arabia and remains busy all year around, especially during the season of Hajj and the month of Ramadan when millions of people visit this city. This emphasizes the importance of clean air and of understanding the sources of various air pollutants, which is vital for the management and advanced modeling of air pollution. This study intends to identify the major sources of air pollutants in Makkah, near the Holy Mosque (Al-Haram using a graphical approach. Air pollutants considered in this study are nitrogen oxides (NOx, nitrogen dioxide (NO2, nitric oxide (NO, carbon monoxide (CO, sulphur dioxide (SO2, ozone (O3 and particulate matter with aero-dynamic diameter of 10 um or less (PM10. Polar plots, time variation plots and correlation analysis are used to analyse the data and identify the major sources of emissions. Most of the pollutants demonstrate high concentrations during the morning traffic peak hours, suggesting road traffic as the main source of emission. The main sources of pollutant emissions identified in Makkahwere road traffic, re-suspended and windblown dust and sand particles. Further investigation on detailedsource apportionment is required, which is part of the ongoing project.

  17. A THEORETICAL ANALYSIS OF KEY POINTS WHEN CHOOSING OPEN SOURCE ERP SYSTEMS

    Directory of Open Access Journals (Sweden)

    Fernando Gustavo Dos Santos Gripe

    2011-08-01

    Full Text Available The present work is aimed at presenting a theoretical analysis of the main features of Open Source ERP systems, herein identified as success technical factors, in order to contribute to the establishment of parameters to be used in decision-making processes when choosing a system which fulfills the organization´s needs. Initially, the life cycle of ERP systems is contextualized, highlighting the features of Open Source ERP systems. As a result, it was verified that, when carefully analyzed, these systems need further attention regarding issues of project continuity and maturity, structure, transparency, updating frequency, and support, all of which are inherent to the reality of this type of software. Nevertheless, advantages were observed in what concerns flexibility, costs, and non-discontinuity as benefits. The main goal is to broaden the discussion about the adoption of Open Source ERP systems.

  18. SREM - WRS system module number 3348 for calculating the removal flux due to point, line or disc sources

    International Nuclear Information System (INIS)

    Grimstone, M.J.

    1978-06-01

    The WRS Modular Programming System has been developed as a means by which programmes may be more efficiently constructed, maintained and modified. In this system a module is a self-contained unit typically composed of one or more Fortran routines, and a programme is constructed from a number of such modules. This report describes one WRS module, the function of which is to calculate the uncollided flux and first-collision source from a disc source in a slab geometry system, a line source at the centre of a cylindrical system or a point source at the centre of a spherical system. The information given in this manual is of use both to the programmer wishing to incorporate the module in a programme, and to the user of such a programme. (author)

  19. Methane Flux Estimation from Point Sources using GOSAT Target Observation: Detection Limit and Improvements with Next Generation Instruments

    Science.gov (United States)

    Kuze, A.; Suto, H.; Kataoka, F.; Shiomi, K.; Kondo, Y.; Crisp, D.; Butz, A.

    2017-12-01

    Atmospheric methane (CH4) has an important role in global radiative forcing of climate but its emission estimates have larger uncertainties than carbon dioxide (CO2). The area of anthropogenic emission sources is usually much smaller than 100 km2. The Thermal And Near infrared Sensor for carbon Observation Fourier-Transform Spectrometer (TANSO-FTS) onboard the Greenhouse gases Observing SATellite (GOSAT) has measured CO2 and CH4 column density using sun light reflected from the earth's surface. It has an agile pointing system and its footprint can cover 87-km2 with a single detector. By specifying pointing angles and observation time for every orbit, TANSO-FTS can target various CH4 point sources together with reference points every 3 day over years. We selected a reference point that represents CH4 background density before or after targeting a point source. By combining satellite-measured enhancement of the CH4 column density and surface measured wind data or estimates from the Weather Research and Forecasting (WRF) model, we estimated CH4emission amounts. Here, we picked up two sites in the US West Coast, where clear sky frequency is high and a series of data are available. The natural gas leak at Aliso Canyon showed a large enhancement and its decrease with time since the initial blowout. We present time series of flux estimation assuming the source is single point without influx. The observation of the cattle feedlot in Chino, California has weather station within the TANSO-FTS footprint. The wind speed is monitored continuously and the wind direction is stable at the time of GOSAT overpass. The large TANSO-FTS footprint and strong wind decreases enhancement below noise level. Weak wind shows enhancements in CH4, but the velocity data have large uncertainties. We show the detection limit of single samples and how to reduce uncertainty using time series of satellite data. We will propose that the next generation instruments for accurate anthropogenic CO2 and CH

  20. Strategic GHG reduction through the use of ground source heat pump technology

    International Nuclear Information System (INIS)

    Hanova, J; Dowlatabadi, H

    2007-01-01

    Higher energy prices and concern about climate change is drawing increasing attention to ground source heat pump (GSHP) systems. Their clear advantage lies in being able to provide heating using 25 to 30% of the energy consumed by even the most efficient conventional alternatives. Their drawback has been high capital costs and uncertainty about whether the emissions associated with the electric power used to energise the system has higher system-wide emissions than the highest-efficiency furnaces. This study delineates circumstances under which GSHP systems achieve net emission reductions, for different electricity generation methods, heat pump efficiencies, and heating loads. We illustrate the effect of relative fuel prices on annual operating savings using fuel prices in multiple countries. Annual operating savings determine how rapidly the technology achieves payback and then generates return on the initial capital investment. Finally, we highlight the least cost supply curve for using GSHP to reduce greenhouse gas emissions. Using the United States as a base reference case, this study explores the potential of GSHP in cold-climate countries worldwide

  1. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 2. Groundwater contaminant mass discharge reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Lange, Ida Vedel; Bjerg, Poul Løgstrup

    2012-01-01

    The impact of source mass depletion on the down-gradient contaminant mass discharge was monitored for a 19-month period as a part of a field demonstration of the ZVI-Clay soil mixing remediation technology. Groundwater samples were collected from conventional monitoring wells (120 samples) and a ...... down-gradient contaminant mass discharge reduction (76%) for the parent compound (PCE), while the overall reduction of chlorinated ethenes was smaller (21%)....

  2. Sterile paper points as a bacterial DNA-contamination source in microbiome profiles of clinical samples

    NARCIS (Netherlands)

    van der Horst, J.; Buijs, M.J.; Laine, M.L.; Wismeijer, D.; Loos, B.G.; Crielaard, W.; Zaura, E.

    2013-01-01

    Objectives High throughput sequencing of bacterial DNA from clinical samples provides untargeted, open-ended information on the entire microbial community. The downside of this approach is the vulnerability to DNA contamination from other sources than the clinical sample. Here we describe

  3. Improving sourcing decisions in NPD projects: Monetary quantification of points of difference

    NARCIS (Netherlands)

    Wouters, Marc; Anderson, James C.; Narus, James A.; Wynstra, Finn

    2009-01-01

    During new product development (NPD), firms make critical design and sourcing decisions that determine the new product's cost, performance, competitive position, and profitability. The purchase price of materials and components for the new product provides only part of the picture for design and

  4. Forced sound transmission through a finite-sized single leaf panel subject to a point source excitation.

    Science.gov (United States)

    Wang, Chong

    2018-03-01

    In the case of a point source in front of a panel, the wavefront of the incident wave is spherical. This paper discusses spherical sound waves transmitting through a finite sized panel. The forced sound transmission performance that predominates in the frequency range below the coincidence frequency is the focus. Given the point source located along the centerline of the panel, forced sound transmission coefficient is derived through introducing the sound radiation impedance for spherical incident waves. It is found that in addition to the panel mass, forced sound transmission loss also depends on the distance from the source to the panel as determined by the radiation impedance. Unlike the case of plane incident waves, sound transmission performance of a finite sized panel does not necessarily converge to that of an infinite panel, especially when the source is away from the panel. For practical applications, the normal incidence sound transmission loss expression of plane incident waves can be used if the distance between the source and panel d and the panel surface area S satisfy d/S>0.5. When d/S ≈0.1, the diffuse field sound transmission loss expression may be a good approximation. An empirical expression for d/S=0  is also given.

  5. A Spatial and Temporal Assessment of Non-Point Groundwater Pollution Sources, Tutuila Island, American Samoa

    Science.gov (United States)

    Shuler, C. K.; El-Kadi, A. I.; Dulaiova, H.; Glenn, C. R.; Fackrell, J.

    2015-12-01

    The quality of municipal groundwater supplies on Tutuila, the main island in American Samoa, is currently in question. A high vulnerability for contamination from surface activities has been recognized, and there exists a strong need to clearly identify anthropogenic sources of pollution and quantify their influence on the aquifer. This study examines spatial relationships and time series measurements of nutrients and other tracers to identify predominant pollution sources and determine the water quality impacts of the island's diverse land uses. Elevated groundwater nitrate concentrations are correlated with areas of human development, however, the mixture of residential and agricultural land use in this unique village based agrarian setting makes specific source identification difficult using traditional geospatial analysis. Spatial variation in anthropogenic impact was assessed by linking NO3- concentrations and δ15N(NO3) from an extensive groundwater survey to land-use types within well capture zones and groundwater flow-paths developed with MODFLOW, a numerical groundwater model. Land use types were obtained from high-resolution GIS data and compared to water quality results with multiple-regression analysis to quantify the impact that different land uses have on water quality. In addition, historical water quality data and new analyses of δD and δ18O in precipitation, groundwater, and mountain-front recharge waters were used to constrain the sources and mechanisms of contamination. Our analyses indicate that groundwater nutrient levels on Tutuila are controlled primarily by residential, not agricultural activity. Also a lack of temporal variation suggests that episodic pollution events are limited to individual water sources as opposed to the entire aquifer. These results are not only valuable for water quality management on Tutuila, but also provide insight into the sustainability of groundwater supplies on other islands with similar hydrogeology and land

  6. Estimation of Multiple Point Sources for Linear Fractional Order Systems Using Modulating Functions

    KAUST Repository

    Belkhatir, Zehor

    2017-06-28

    This paper proposes an estimation algorithm for the characterization of multiple point inputs for linear fractional order systems. First, using polynomial modulating functions method and a suitable change of variables the problem of estimating the locations and the amplitudes of a multi-pointwise input is decoupled into two algebraic systems of equations. The first system is nonlinear and solves for the time locations iteratively, whereas the second system is linear and solves for the input’s amplitudes. Second, closed form formulas for both the time location and the amplitude are provided in the particular case of single point input. Finally, numerical examples are given to illustrate the performance of the proposed technique in both noise-free and noisy cases. The joint estimation of pointwise input and fractional differentiation orders is also presented. Furthermore, a discussion on the performance of the proposed algorithm is provided.

  7. Generation of point isotropic source dose buildup factor data for the PFBR special concretes in a form compatible for usage in point kernel computer code QAD-CGGP

    International Nuclear Information System (INIS)

    Radhakrishnan, G.

    2003-01-01

    Full text: Around the PFBR (Prototype Fast Breeder Reactor) reactor assembly, in the peripheral shields special concretes of density 2.4 g/cm 3 and 3.6 g/cm 3 are to be used in complex geometrical shapes. Point-kernel computer code like QAD-CGGP, written for complex shield geometry comes in handy for the shield design optimization of peripheral shields. QAD-CGGP requires data base for the buildup factor data and it contains only ordinary concrete of density 2.3 g/cm 3 . In order to extend the data base for the PFBR special concretes, point isotropic source dose buildup factors have been generated by Monte Carlo method using the computer code MCNP-4A. For the above mentioned special concretes, buildup factor data have been generated in the energy range 0.5 MeV to 10.0 MeV with the thickness ranging from 1 mean free paths (mfp) to 40 mfp. Capo's formula fit of the buildup factor data compatible with QAD-CGGP has been attempted

  8. On-site meteorological instrumentation requirements to characterize diffusion from point sources: workshop report. Final report Sep 79-Sep 80

    International Nuclear Information System (INIS)

    Strimaitis, D.; Hoffnagle, G.; Bass, A.

    1981-04-01

    Results of a workshop entitled 'On-Site Meteorological Instrumentation Requirements to Characterize Diffusion from Point Sources' are summarized and reported. The workshop was sponsored by the U.S. Environmental Protection Agency in Raleigh, North Carolina, on January 15-17, 1980. Its purpose was to provide EPA with a thorough examination of the meteorological instrumentation and data collection requirements needed to characterize airborne dispersion of air contaminants from point sources and to recommend, based on an expert consensus, specific measurement technique and accuracies. Secondary purposes of the workshop were to (1) make recommendations to the National Weather Service (NWS) about collecting and archiving meteorological data that would best support air quality dispersion modeling objectives and (2) make recommendations on standardization of meteorological data reporting and quality assurance programs

  9. Correlation Wave-Front Sensing Algorithms for Shack-Hartmann-Based Adaptive Optics using a Point Source

    International Nuclear Information System (INIS)

    Poynee, L A

    2003-01-01

    Shack-Hartmann based Adaptive Optics system with a point-source reference normally use a wave-front sensing algorithm that estimates the centroid (center of mass) of the point-source image 'spot' to determine the wave-front slope. The centroiding algorithm suffers for several weaknesses. For a small number of pixels, the algorithm gain is dependent on spot size. The use of many pixels on the detector leads to significant propagation of read noise. Finally, background light or spot halo aberrations can skew results. In this paper an alternative algorithm that suffers from none of these problems is proposed: correlation of the spot with a ideal reference spot. The correlation method is derived and a theoretical analysis evaluates its performance in comparison with centroiding. Both simulation and data from real AO systems are used to illustrate the results. The correlation algorithm is more robust than centroiding, but requires more computation

  10. A rotating modulation imager for locating mid-range point sources

    International Nuclear Information System (INIS)

    Kowash, B.R.; Wehe, D.K.; Fessler, J.A.

    2009-01-01

    Rotating modulation collimators (RMC) are relatively simple indirect imaging devices that have proven useful in gamma ray astronomy (far field) and have more recently been studied for medical imaging (very near field). At the University of Michigan a RMC has been built to study the performance for homeland security applications. This research highlights the imaging performance of this system and focuses on three distinct regions in the RMC field of view that can impact the search for hidden sources. These regions are a blind zone around the axis of rotation, a two mask image zone that extends from the blind zone to the edge of the field of view, and a single mask image zone that occurs when sources fall outside the field of view of both masks. By considering the extent and impact of these zones, the size of the two mask region can be optimized for the best system performance.

  11. The Non-point Source Pollution Effects of Pesticides Based on the Survey of 340 Farmers in Chongqing City

    OpenAIRE

    YU, Lianchao; GU, Limeng; BI, Qian

    2015-01-01

    Using the survey data on 340 farmers in Chongqing City, this paper performs an empirical analysis of the factors influencing the non-point source pollution of pesticides. The results show that the older householders will apply more pesticides, which may be due to the weak physical strength and weak ability to accept the concept of advanced cultivation; the householders with high level of education will choose to use less pesticides; the pesticide application rate is negatively correlated with...

  12. Analytical formulae to calculate the solid angle subtended at an arbitrarily positioned point source by an elliptical radiation detector

    International Nuclear Information System (INIS)

    Abbas, Mahmoud I.; Hammoud, Sami; Ibrahim, Tarek; Sakr, Mohamed

    2015-01-01

    In this article, we introduce a direct analytical mathematical method for calculating the solid angle, Ω, subtended at a point by closed elliptical contours. The solid angle is required in many areas of optical and nuclear physics to estimate the flux of particle beam of radiation and to determine the activity of a radioactive source. The validity of the derived analytical expressions was successfully confirmed by the comparison with some published data (Numerical Method)

  13. Study The Validity of The Direct Mathematical Method For Calculation The Total Efficiency Using Point And Disk Sources

    International Nuclear Information System (INIS)

    Hagag, O.M.; Nafee, S.S.; Naeem, M.A.; El Khatib, A.M.

    2011-01-01

    The direct mathematical method has been developed for calculating the total efficiency of many cylindrical gamma detectors, especially HPGe and NaI detector. Different source geometries are considered (point and disk). Further into account is taken of gamma attenuation from detector window or any interfacing absorbing layer. Results are compared with published experimental data to study the validity of the direct mathematical method to calculate total efficiency for any gamma detector size.

  14. Reducing errors in aircraft atmospheric inversion estimates of point-source emissions: the Aliso Canyon natural gas leak as a natural tracer experiment

    Science.gov (United States)

    Gourdji, S. M.; Yadav, V.; Karion, A.; Mueller, K. L.; Conley, S.; Ryerson, T.; Nehrkorn, T.; Kort, E. A.

    2018-04-01

    Urban greenhouse gas (GHG) flux estimation with atmospheric measurements and modeling, i.e. the ‘top-down’ approach, can potentially support GHG emission reduction policies by assessing trends in surface fluxes and detecting anomalies from bottom-up inventories. Aircraft-collected GHG observations also have the potential to help quantify point-source emissions that may not be adequately sampled by fixed surface tower-based atmospheric observing systems. Here, we estimate CH4 emissions from a known point source, the Aliso Canyon natural gas leak in Los Angeles, CA from October 2015–February 2016, using atmospheric inverse models with airborne CH4 observations from twelve flights ≈4 km downwind of the leak and surface sensitivities from a mesoscale atmospheric transport model. This leak event has been well-quantified previously using various methods by the California Air Resources Board, thereby providing high confidence in the mass-balance leak rate estimates of (Conley et al 2016), used here for comparison to inversion results. Inversions with an optimal setup are shown to provide estimates of the leak magnitude, on average, within a third of the mass balance values, with remaining errors in estimated leak rates predominantly explained by modeled wind speed errors of up to 10 m s‑1, quantified by comparing airborne meteorological observations with modeled values along the flight track. An inversion setup using scaled observational wind speed errors in the model-data mismatch covariance matrix is shown to significantly reduce the influence of transport model errors on spatial patterns and estimated leak rates from the inversions. In sum, this study takes advantage of a natural tracer release experiment (i.e. the Aliso Canyon natural gas leak) to identify effective approaches for reducing the influence of transport model error on atmospheric inversions of point-source emissions, while suggesting future potential for integrating surface tower and

  15. The Newtonian force experienced by a point mass near a finite cylindrical source

    International Nuclear Information System (INIS)

    Selvaggi, Jerry P; Salon, Sheppard; Chari, M V K

    2008-01-01

    The Newtonian gravitational force experienced by a point mass located at some external point from a thick-walled, hollow and uniform finite circular cylindrical body was recently solved by Lockerbie, Veryaskin and Xu (1993 Class. Quantum Grav. 10 2419). Their method of attack relied on the introduction of the circular cylindrical free-space Green function representation for the inverse distance which appears in the formulation of the Newtonian potential function. This ultimately leads Lockerbie et al to a final expression for the Newtonian potential function which is expressed as a double summation of even-ordered Legendre polynomials. However, the kernel of the cylindrical free-space Green function which is represented by an infinite integral of the product of two Bessel functions and a decaying exponential can be analytically evaluated in terms of a toroidal function. This leads to a simplification in the mathematical analysis developed by Lockerbie et al. Also, each term in the infinite series solution for the Newtonian potential function can be expressed in closed form in terms of elementary functions. The authors develop the Newtonian potential function by employing toroidal functions of zeroth order or Legendre functions of half-integral degree, Q m-1/2 (β)(Bouwkamp and de Bruijn 1947 J. Appl. Phys.18 562, Cohl et al 2001 Phys. Rev.A 64 052509-1, Selvaggi et al 2004 IEEE Trans. Magn.40 3278). These functions are monotonically decreasing and converge rapidly (Moon and Spencer 1961 Field Theory for Engineers (New Jersey: Van Nostrand Company) pp 368-76, Cohl and Tohline 1999 Astrophys. J.527 86). The introduction of the toroidal harmonic expansion leads to an infinite series solution for which each term can be expressed as an elementary function. This enables one to easily compute the axial and radial forces experienced by an internal or an external point mass

  16. Tracking an oil slick from multiple natural sources, Coal Oil Point, California

    International Nuclear Information System (INIS)

    Leifer, Ira; Luyendyk, Bruce; Broderick, Kris

    2006-01-01

    Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

  17. Tracking an oil slick from multiple natural sources, Coal Oil Point, California

    Energy Technology Data Exchange (ETDEWEB)

    Leifer, Ira [Marine Sciences Institute, University of California, Santa Barbara, CA 93106 (United States); Luyendyk, Bruce [Department of Geological Sciences, University of California, Santa Barbara, CA 93106 (United States); Broderick, Kris [Exxon/Mobil Exploration Company, 13401 N. Freeway, Houston, TX 77060 (United States)

    2006-06-15

    Oil slicks on the ocean surface emitted from natural marine hydrocarbon seeps offshore from Coal Oil Point in the Santa Barbara Channel, California were tracked and sampled over a 2-h period. The objectives were to characterize the seep oil and to track its composition over time using a new sampling device, a catamaran drum sampler (CATDRUMS). The sampler was designed and developed at UCSB. Chromatograms showed that oil originating from an informally named, very active seep area, Shane Seep, primarily evolved during the first hour due to mixing with oil originating from a convergence zone slick surrounding Shane Seep. (author)

  18. Radiological Threat Reduction (RTR) program: implementing physical security to protect large radioactive sources worldwide

    International Nuclear Information System (INIS)

    Lowe, Daniel L.

    2004-01-01

    The U.S. Department of Energy's Radiological Threat Reduction (RTR) Program strives to reduce the threat of a Radiological Dispersion Device (RDD) incident that could affect U.S. interests worldwide. Sandia National Laboratories supports the RTR program on many different levels. Sandia works directly with DOE to develop strategies, including the selection of countries to receive support and the identification of radioactive materials to be protected. Sandia also works with DOE in the development of guidelines and in training DOE project managers in physical protection principles. Other support to DOE includes performing rapid assessments and providing guidance for establishing foreign regulatory and knowledge infrastructure. Sandia works directly with foreign governments to establish cooperative agreements necessary to implement the RTR Program efforts to protect radioactive sources. Once necessary agreements are in place, Sandia works with in-country organizations to implement various security related initiatives, such as installing security systems and searching for (and securing) orphaned radioactive sources. The radioactive materials of interest to the RTR program include Cobalt 60, Cesium 137, Strontium 90, Iridium 192, Radium 226, Plutonium 238, Americium 241, Californium 252, and Others. Security systems are implemented using a standardized approach that provides consistency through out the RTR program efforts at Sandia. The approach incorporates a series of major tasks that overlap in order to provide continuity. The major task sequence is to: Establish in-country contacts - integrators, Obtain material characterizations, Perform site assessments and vulnerability assessments, Develop upgrade plans, Procure and install equipment, Conduct acceptance testing and performance testing, Develop procedures, and Conduct training. Other tasks are incorporated as appropriate and commonly include such as support of reconfiguring infrastructure, and developing security

  19. Search for atmospheric muon-neutrinos and extraterrestric neutrino point sources in the 1997 AMANDA-B10 data

    International Nuclear Information System (INIS)

    Biron von Curland, A.

    2002-07-01

    The young field of high energy neutrino astronomy can be motivated by the search for the origin of the charged cosmic rays. Large astrophysical objects like AGNs or supernova remnants are candidates to accelerate hadrons which then can interact to eventually produce high energy neutrinos. Neutrino-induced muons can be detected via their emission of Cherenkov light in large neutrino telescopes like AMANDA. More than 10 9 atmospheric muon events and approximately 5000 atmospheric neutrino events were registered by AMANDA-B10 in 1997. Out of these, 223 atmospheric neutrino candidate events have been extracted. This data set contains approximately 15 background events. It allows to confirm the expected sensitivity of the detector towards neutrino events. A second set containing 369 (approximately 270 atmospheric neutrino events and 100 atmospheric muon events) was used to search for extraterrestrial neutrino point sources. Neither a binned search, nor a cluster search, nor a search for preselected sources gave indications for the existence of a strong neutrino point source. Based on this result, flux limits were derived. Assuming E ν -2 spectra, typical flux limits for selected sources of the order of Φ μ limit ∝ 10 -14 cm -2 s -1 for muons and Φ ν limit ∝ 10 -7 cm -2 s -1 for neutrinos have been obtained. (orig.)

  20. Energy demand modelling: pointing out alternative energy sources. The example of industry in OECD countries

    International Nuclear Information System (INIS)

    Renou, P.

    1992-01-01

    This thesis studies energy demand and alternative energy sources in OECD countries. In the first part, the principle models usually used for energy demand modelling. In the second part, the author studies the flexible functional forms (translog, generalized Leontief, generalized quadratic, Fourier) to obtain an estimation of the production function. In the third part, several examples are given, chosen in seven countries (Usa, Japan, Federal Republic of Germany, France, United Kingdom, Italy, Canada). Energy systems analysis in these countries, can help to choose models and gives informations on alternative energies. 246 refs., 24 figs., 27 tabs

  1. PSD Applicability Determination for Multiple Owner/Operator Point Sources Within a Single Facility

    Science.gov (United States)

    This document may be of assistance in applying the New Source Review (NSR) air permitting regulations including the Prevention of Significant Deterioration (PSD) requirements. This document is part of the NSR Policy and Guidance Database. Some documents in the database are a scanned or retyped version of a paper photocopy of the original. Although we have taken considerable effort to quality assure the documents, some may contain typographical errors. Contact the office that issued the document if you need a copy of the original.

  2. Source to point of use drinking water changes and knowledge, attitude and practices in Katsina State, Northern Nigeria

    Science.gov (United States)

    Onabolu, B.; Jimoh, O. D.; Igboro, S. B.; Sridhar, M. K. C.; Onyilo, G.; Gege, A.; Ilya, R.

    In many Sub-Saharan countries such as Nigeria, inadequate access to safe drinking water is a serious problem with 37% in the region and 58% of rural Nigeria using unimproved sources. The global challenge to measuring household water quality as a determinant of safety is further compounded in Nigeria by the possibility of deterioration from source to point of use. This is associated with the use of decentralised water supply systems in rural areas which are not fully reticulated to the household taps, creating a need for an integrated water quality monitoring system. As an initial step towards establishing the system in the north west and north central zones of Nigeria, The Katsina State Rural Water and Sanitation Agency, responsible for ensuring access to safe water and adequate sanitation to about 6 million people carried out a three pronged study with the support of UNICEF Nigeria. Part 1 was an assessment of the legislative and policy framework, institutional arrangements and capacity for drinking water quality monitoring through desk top reviews and Key Informant Interviews (KII) to ascertain the institutional capacity requirements for developing the water quality monitoring system. Part II was a water quality study in 700 households of 23 communities in four local government areas. The objectives were to assess the safety of drinking water, compare the safety at source and household level and assess the possible contributory role of end users’ Knowledge Attitudes and Practices. These were achieved through water analysis, household water quality tracking, KII and questionnaires. Part III was the production of a visual documentary as an advocacy tool to increase awareness of the policy makers of the linkages between source management, treatment and end user water quality. The results indicate that except for pH, conductivity and manganese, the improved water sources were safe at source. However there was a deterioration in water quality between source and

  3. Electronic equilibrium as a function of depth in tissue from cobalt-60 point source exposures

    International Nuclear Information System (INIS)

    Myrick, J.A.

    1994-08-01

    The Nuclear Regulatory Commission has set the basic criteria for assessing skin dose stemming from hot particle contaminations. Compliance with 10 CFR 20.101 requires that exposure to the skin be evaluated over a 1 cm 2 area at a depth of 0.007 cm. Skin exposure can arise from both the beta and gamma components of radioactive particles and gamma radiation can contribute significantly to skin doses. The gamma component of dose increases dramatically when layers of protective clothing are interposed between the hot particle source and the skin, and in cases where the hot particle is large in comparison to the range of beta particles. Once the protective clothing layer is thicker than the maximum range of the beta particles, skin dose is due solely to gamma radiation. Charged particle equilibrium is not established at shallow depths. The degree of electronic equilibrium establishment must be assessed for shallow doses to prevent the over-assessment of skin dose because conventional fluence-to-dose conversion factors are not applicable. To assess the effect of electronic equilibrium, selected thicknesses of tissue equivalent material were interposed between radiochromic dye film and a 60 Co hot particle source and dose was measured as a function of depth. These measured values were then compared to models which are used to calculate charged particle equilibrium. The Miller-Reece model was found to agree closely with the experimental data while the Lantz-Lambert model overestimated dose at shallow depths

  4. MILLIMETER TRANSIENT POINT SOURCES IN THE SPTpol 100 SQUARE DEGREE SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Whitehorn, N.; Haan, T. de; George, E. M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Natoli, T.; Carlstrom, J. E. [Department of Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Ade, P. A. R. [Cardiff University, Cardiff CF10 3XQ (United Kingdom); Austermann, J. E.; Beall, J. A. [NIST Quantum Devices Group, 325 Broadway Mailcode 817.03, Boulder, CO 80305 (United States); Bender, A. N.; Benson, B. A.; Bleem, L. E.; Chang, C. L.; Citron, R.; Crawford, T. M.; Crites, A. T.; Gallicchio, J. [Kavli Institute for Cosmological Physics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Chiang, H. C. [School of Mathematics, Statistics and Computer Science, University of KwaZulu-Natal, Durban (South Africa); Cho, H-M. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Dobbs, M. A. [Department of Physics, McGill University, 3600 Rue University, Montreal, Quebec H3A 2T8 (Canada); Everett, W., E-mail: nwhitehorn@berkeley.edu, E-mail: t.natoli@utoronto.ca [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); and others

    2016-10-20

    The millimeter transient sky is largely unexplored, with measurements limited to follow-up of objects detected at other wavelengths. High-angular-resolution telescopes, designed for measurement of the cosmic microwave background (CMB), offer the possibility to discover new, unknown transient sources in this band—particularly the afterglows of unobserved gamma-ray bursts (GRBs). Here, we use the 10 m millimeter-wave South Pole Telescope, designed for the primary purpose of observing the CMB at arcminute and larger angular scales, to conduct a search for such objects. During the 2012–2013 season, the telescope was used to continuously observe a 100 deg{sup 2} patch of sky centered at R.A. 23{sup h}30{sup m} and decl. −55° using the polarization-sensitive SPTpol camera in two bands centered at 95 and 150 GHz. These 6000 hr of observations provided continuous monitoring for day- to month-scale millimeter-wave transient sources at the 10 mJy level. One candidate object was observed with properties broadly consistent with a GRB afterglow, but at a statistical significance too low ( p = 0.01) to confirm detection.

  5. Airborne remote sensing and in situ measurements of atmospheric CO2 to quantify point source emissions

    Science.gov (United States)

    Krings, Thomas; Neininger, Bruno; Gerilowski, Konstantin; Krautwurst, Sven; Buchwitz, Michael; Burrows, John P.; Lindemann, Carsten; Ruhtz, Thomas; Schüttemeyer, Dirk; Bovensmann, Heinrich

    2018-02-01

    Reliable techniques to infer greenhouse gas emission rates from localised sources require accurate measurement and inversion approaches. In this study airborne remote sensing observations of CO2 by the MAMAP instrument and airborne in situ measurements are used to infer emission estimates of carbon dioxide released from a cluster of coal-fired power plants. The study area is complex due to sources being located in close proximity and overlapping associated carbon dioxide plumes. For the analysis of in situ data, a mass balance approach is described and applied, whereas for the remote sensing observations an inverse Gaussian plume model is used in addition to a mass balance technique. A comparison between methods shows that results for all methods agree within 10 % or better with uncertainties of 10 to 30 % for cases in which in situ measurements were made for the complete vertical plume extent. The computed emissions for individual power plants are in agreement with results derived from emission factors and energy production data for the time of the overflight.

  6. Sources of Aid and Resilience and Points of Pain in Jamaican Migrant Families

    OpenAIRE

    Thompson, Paul; Bauer, Elaine

    2008-01-01

    Soutien, résilience et points douloureux dans les familles jamaïcaines transnationales.L’article se fonde sur des récits de vie recueillis auprès de membres de 45 familles qui ont de la parentèle à la fois en Jamaïque, en Grande-Bretagne et en Amérique du Nord. L’idée centrale est que la forme jamaïcaine transnationale de famille est centrée sur un type de structure familiale qui est complexe, informel, et pragmatique ; ce type de structure serait caractéristique de la parenté jamaïcaine depu...

  7. Advection-diffusion model for the simulation of air pollution distribution from a point source emission

    Science.gov (United States)

    Ulfah, S.; Awalludin, S. A.; Wahidin

    2018-01-01

    Advection-diffusion model is one of the mathematical models, which can be used to understand the distribution of air pollutant in the atmosphere. It uses the 2D advection-diffusion model with time-dependent to simulate air pollution distribution in order to find out whether the pollutants are more concentrated at ground level or near the source of emission under particular atmospheric conditions such as stable, unstable, and neutral conditions. Wind profile, eddy diffusivity, and temperature are considered in the model as parameters. The model is solved by using explicit finite difference method, which is then visualized by a computer program developed using Lazarus programming software. The results show that the atmospheric conditions alone influencing the level of concentration of pollutants is not conclusive as the parameters in the model have their own effect on each atmospheric condition.

  8. Typhoid fever: A report on a point-source outbreak of 69 cases in Cape Town.

    Science.gov (United States)

    Popkiss, M E

    1980-03-01

    In 1978, after a party in a Cape Town suburb attended by several hundred people, 69 persons were treated for typhoid fever. The precise source of the infection could not be traced, although it is reasonable to suppose that food eaten at the party had been contaminated by the main caterer. All 57 cultures of Salmonella typhi phage-typed were of phage type 46, including that obtained from the stool of the main caterer, who was asymptomatic. An epidemiological profile of the cases and an account of the management of the outbreak is given. There were no deaths and no patient became a carrier. Although the outbreak was contained, certain problems relating thereto are aired, including in particular the potential hazard of food-borne disease wherever housing and environmental standards are low.

  9. Near-field interferometry of a free-falling nanoparticle from a point-like source

    Science.gov (United States)

    Bateman, James; Nimmrichter, Stefan; Hornberger, Klaus; Ulbricht, Hendrik

    2014-09-01

    Matter-wave interferometry performed with massive objects elucidates their wave nature and thus tests the quantum superposition principle at large scales. Whereas standard quantum theory places no limit on particle size, alternative, yet untested theories—conceived to explain the apparent quantum to classical transition—forbid macroscopic superpositions. Here we propose an interferometer with a levitated, optically cooled and then free-falling silicon nanoparticle in the mass range of one million atomic mass units, delocalized over >150 nm. The scheme employs the near-field Talbot effect with a single standing-wave laser pulse as a phase grating. Our analysis, which accounts for all relevant sources of decoherence, indicates that this is a viable route towards macroscopic high-mass superpositions using available technology.

  10. Diverse origins of Arctic and Subarctic methane point source emissions identified with multiply-substituted isotopologues

    Science.gov (United States)

    Douglas, P. M. J.; Stolper, D. A.; Smith, D. A.; Walter Anthony, K. M.; Paull, C. K.; Dallimore, S.; Wik, M.; Crill, P. M.; Winterdahl, M.; Eiler, J. M.; Sessions, A. L.

    2016-09-01

    Methane is a potent greenhouse gas, and there are concerns that its natural emissions from the Arctic could act as a substantial positive feedback to anthropogenic global warming. Determining the sources of methane emissions and the biogeochemical processes controlling them is important for understanding present and future Arctic contributions to atmospheric methane budgets. Here we apply measurements of multiply-substituted isotopologues, or clumped isotopes, of methane as a new tool to identify the origins of ebullitive fluxes in Alaska, Sweden and the Arctic Ocean. When methane forms in isotopic equilibrium, clumped isotope measurements indicate the formation temperature. In some microbial methane, however, non-equilibrium isotope effects, probably related to the kinetics of methanogenesis, lead to low clumped isotope values. We identify four categories of emissions in the studied samples: thermogenic methane, deep subsurface or marine microbial methane formed in isotopic equilibrium, freshwater microbial methane with non-equilibrium clumped isotope values, and mixtures of deep and shallow methane (i.e., combinations of the first three end members). Mixing between deep and shallow methane sources produces a non-linear variation in clumped isotope values with mixing proportion that provides new constraints for the formation environment of the mixing end-members. Analyses of microbial methane emitted from lakes, as well as a methanol-consuming methanogen pure culture, support the hypothesis that non-equilibrium clumped isotope values are controlled, in part, by kinetic isotope effects induced during enzymatic reactions involved in methanogenesis. Our results indicate that these kinetic isotope effects vary widely in microbial methane produced in Arctic lake sediments, with non-equilibrium Δ18 values spanning a range of more than 5‰.

  11. Point X-ray sources in the SNR G 315.4-2.30 (MSH 14-63, RCW 86)

    Science.gov (United States)

    Gvaramadze, V. V.; Vikhlinin, A. A.

    2003-04-01

    We report the results of a search for a point X-ray source (stellar remnant) in the southwest protrusion of the supernova remnant G 315.4-2.30 (MSH 14-63, RCW 86) using the archival data of the Chandra X-ray Observatory. The search was motivated by a hypothesis that G 315.4-2.30 is the result of an off-centered cavity supernova explosion of a moving massive star, which ended its evolution just near the edge of the main-sequence wind-driven bubble. This hypothesis implies that the southwest protrusion in G 315.4-2.30 is the remainder of a pre-existing bow shock-like structure created by the interaction of the supernova progenitor's wind with the interstellar medium and that the actual location of the supernova blast center is near the center of this hemispherical structure. We have discovered two point X-ray sources in the ``proper" place. One of the sources has an optical counterpart with the photographic magnitude 13.38+/-0.40, while the spectrum of the source can be fitted with an optically thin plasma model. We interpret this source as a foreground active star of late spectral type. The second source has no optical counterpart to a limiting magnitude ~ 21. The spectrum of this source can be fitted almost equally well with several simple models (power law: photon index =1.87; two-temperature blackbody: kT1 =0.11 keV, R1 =2.34 km and kT2 =0.71 keV, R2 =0.06 km; blackbody plus power law: kT =0.07 keV, photon index =2.3). We interpret this source as a candidate stellar remnant (neutron star), while the photon index and non-thermal luminosity of the source (almost the same as those of the Vela pulsar and the recently discovered pulsar PSR J 0205+6449 in the supernova remnant 3C 58) suggest that it can be a young ``ordinary" pulsar.

  12. ZVI-Clay remediation of a chlorinated solvent source zone, Skuldelev, Denmark: 1. Site description and contaminant source mass reduction

    DEFF Research Database (Denmark)

    Fjordbøge, Annika Sidelmann; Riis, Charlotte; Christensen, Anders G.

    2012-01-01

    Field investigations on the effects of ZVI-Clay soil mixing were conducted at a small DNAPL source zone with PCE as the parent compound. In a one-year monitoring program, soil samples were collected at three horizontal sampling planes (2.5, 5.0 and 7.5m bgs.). PCE was found to have a pseudo first...

  13. The Crowding-Out Effects of Garbage Fees and Voluntary Source Separation Programs on Waste Reduction: Evidence from China

    Directory of Open Access Journals (Sweden)

    Hongyun Han

    2016-07-01

    Full Text Available This paper examines how and to what degree government policies of garbage fees and voluntary source separation programs, with free indoor containers and garbage bags, can affect the effectiveness of municipal solid waste (MSW management, in the sense of achieving a desirable reduction of per capita MSW generation. Based on city-level panel data for years 1998–2012 in China, our empirical analysis indicates that per capita MSW generated is increasing with per capita disposable income, average household size, education levels of households, and the lagged per capita MSW. While both garbage fees and source separation programs have separately led to reductions in per capita waste generation, the interaction of the two policies has resulted in an increase in per capita waste generation due to the following crowding-out effects: Firstly, the positive effect of income dominates the negative effect of the garbage fee. Secondly, there are crowding-out effects of mandatory charging system and the subsidized voluntary source separation on per capita MSW generation. Thirdly, small subsidies and tax punishments have reduced the intrinsic motivation for voluntary source separation of MSW. Thus, compatible fee charging system, higher levels of subsidies, and well-designed public information and education campaigns are required to promote household waste source separation and reduction.

  14. Vibration of a Cylindrical Tunnel under a Centric Point-Source Explosion

    Directory of Open Access Journals (Sweden)

    Yuetang Zhao

    2017-01-01

    Full Text Available Underground tunnels are vulnerable to terrorists’ bombing attacks, which calls for studies on tunnel’s response to internal explosive loading. In this paper, the dynamic response of a cylindrical tunnel to an ideal centric point explosion was treated as an axisymmetric 2-dimensional problem, in which the tunnel was modeled with a continuous anisotropic shell, while the ground medium’s effect was accounted for with linear elastic Winkler springs and the explosive loading described by a temporal and spatial function. The governing equation of the motion is a fourth-order partial differential equation, for which a numerical method combining finite difference with the implicit Newmark-β method was adopted. This method avoided complicated integral transform and numerical inverse transformation, thus allowing efficient parameter study. The maximum radial displacement was found on the cricle of the center of explosive, where hoop stress is the maximum principal stress. The anisotropy showed little influence on maximum hoop stress. Within the range of ground medium’s modulus, minor influence on maximum hoop stress was incurred. This research may be helpful to hazard assessment and protective design for some critical subway tunnels.

  15. Iterative image reconstruction for positron emission tomography based on a detector response function estimated from point source measurements

    International Nuclear Information System (INIS)

    Tohme, Michel S; Qi Jinyi

    2009-01-01

    The accuracy of the system model in an iterative reconstruction algorithm greatly affects the quality of reconstructed positron emission tomography (PET) images. For efficient computation in reconstruction, the system model in PET can be factored into a product of a geometric projection matrix and sinogram blurring matrix, where the former is often computed based on analytical calculation, and the latter is estimated using Monte Carlo simulations. Direct measurement of a sinogram blurring matrix is difficult in practice because of the requirement of a collimated source. In this work, we propose a method to estimate the 2D blurring kernels from uncollimated point source measurements. Since the resulting sinogram blurring matrix stems from actual measurements, it can take into account the physical effects in the photon detection process that are difficult or impossible to model in a Monte Carlo (MC) simulation, and hence provide a more accurate system model. Another advantage of the proposed method over MC simulation is that it can easily be applied to data that have undergone a transformation to reduce the data size (e.g., Fourier rebinning). Point source measurements were acquired with high count statistics in a relatively fine grid inside the microPET II scanner using a high-precision 2D motion stage. A monotonically convergent iterative algorithm has been derived to estimate the detector blurring matrix from the point source measurements. The algorithm takes advantage of the rotational symmetry of the PET scanner and explicitly models the detector block structure. The resulting sinogram blurring matrix is incorporated into a maximum a posteriori (MAP) image reconstruction algorithm. The proposed method has been validated using a 3 x 3 line phantom, an ultra-micro resolution phantom and a 22 Na point source superimposed on a warm background. The results of the proposed method show improvements in both resolution and contrast ratio when compared with the MAP

  16. Entropy-Weighted Instance Matching Between Different Sourcing Points of Interest

    Directory of Open Access Journals (Sweden)

    Lin Li

    2016-01-01

    Full Text Available The crucial problem for integrating geospatial data is finding the corresponding objects (the counterpart from different sources. Most current studies focus on object matching with individual attributes such as spatial, name, or other attributes, which avoids the difficulty of integrating those attributes, but at the cost of an ineffective matching. In this study, we propose an approach for matching instances by integrating heterogeneous attributes with the allocation of suitable attribute weights via information entropy. First, a normalized similarity formula is developed, which can simplify the calculation of spatial attribute similarity. Second, sound-based and word segmentation-based methods are adopted to eliminate the semantic ambiguity when there is a lack of a normative coding standard in geospatial data to express the name attribute. Third, category mapping is established to address the heterogeneity among different classifications. Finally, to address the non-linear characteristic of attribute similarity, the weights of the attributes are calculated by the entropy of the attributes. Experiments demonstrate that the Entropy-Weighted Approach (EWA has good performance both in terms of precision and recall for instance matching from different data sets.

  17. Event-based motion correction for PET transmission measurements with a rotating point source

    International Nuclear Information System (INIS)

    Zhou, Victor W; Kyme, Andre Z; Meikle, Steven R; Fulton, Roger

    2011-01-01

    Accurate attenuation correction is important for quantitative positron emission tomography (PET) studies. When performing transmission measurements using an external rotating radioactive source, object motion during the transmission scan can distort the attenuation correction factors computed as the ratio of the blank to transmission counts, and cause errors and artefacts in reconstructed PET images. In this paper we report a compensation method for rigid body motion during PET transmission measurements, in which list mode transmission data are motion corrected event-by-event, based on known motion, to ensure that all events which traverse the same path through the object are recorded on a common line of response (LOR). As a result, the motion-corrected transmission LOR may record a combination of events originally detected on different LORs. To ensure that the corresponding blank LOR records events from the same combination of contributing LORs, the list mode blank data are spatially transformed event-by-event based on the same motion information. The number of counts recorded on the resulting blank LOR is then equivalent to the number of counts that would have been recorded on the corresponding motion-corrected transmission LOR in the absence of any attenuating object. The proposed method has been verified in phantom studies with both stepwise movements and continuous motion. We found that attenuation maps derived from motion-corrected transmission and blank data agree well with those of the stationary phantom and are significantly better than uncorrected attenuation data.

  18. Identifying non-point sources of endocrine active compounds and their biological impacts in freshwater lakes

    Science.gov (United States)

    Baker, Beth H.; Martinovic-Weigelt, Dalma; Ferrey, Mark L.; Barber, Larry B.; Writer, Jeffrey H.; Rosenberry, Donald O.; Kiesling, Richard L.; Lundy, James R.; Schoenfuss, Heiko L.

    2014-01-01

    Contaminants of emerging concern, particularly endocrine active compounds (EACs), have been identified as a threat to aquatic wildlife. However, little is known about the impact of EACs on lakes through groundwater from onsite wastewater treatment systems (OWTS). This study aims to identify specific contributions of OWTS to Sullivan Lake, Minnesota, USA. Lake hydrology, water chemistry, caged bluegill sunfish (Lepomis macrochirus), and larval fathead minnow (Pimephales promelas) exposures were used to assess whether EACs entered the lake through OWTS inflow and the resultant biological impact on fish. Study areas included two OWTS-influenced near-shore sites with native bluegill spawning habitats and two in-lake control sites without nearby EAC sources. Caged bluegill sunfish were analyzed for plasma vitellogenin concentrations, organosomatic indices, and histological pathologies. Surface and porewater was collected from each site and analyzed for EACs. Porewater was also collected for laboratory exposure of larval fathead minnow, before analysis of predator escape performance and gene expression profiles. Chemical analysis showed EACs present at low concentrations at each study site, whereas discrete variations were reported between sites and between summer and fall samplings. Body condition index and liver vacuolization of sunfish were found to differ among study sites as did gene expression in exposed larval fathead minnows. Interestingly, biological exposure data and water chemistry did not match. Therefore, although results highlight the potential impacts of seepage from OWTS, further investigation of mixture effects and life history factor as well as chemical fate is warranted.

  19. Mitigation of non-point source of fluoride on groundwater by dug well recharge

    Science.gov (United States)

    Ganesan, G.; Lakshmanan, E.

    2017-12-01

    Groundwater used for drinking purpose is affected in many regions due to the presence of excess fluoride. The excess intake of fluoride through drinking water causes fluorosis to human in many states of India, including Tamil Nadu. The present study was carried out with the objective of assessing hydrogeochemistry of groundwater and the feasibility of dug well recharge to reduce the fluoride concentration in Vaniyar river basin, Tamil Nadu, India. The major source for fluoride in groundwater of this area is the epidote hornblende gneissic and charnockite which are the major rocks occurring in this region. As a pilot study a cost effective induced recharge structure was constructed at Papichettipatty village in the study region. The study shows that the groundwater level around the recharge site raised up to 2 m from 14.5 m (bgl) and fluoride concentration has decreased from 3.8 mg/l to 0.9 mg/l due to dilution. The advantage of this induced recharge structure is of its low cost, the ease of implementation, improved groundwater recharge and dilution of fluoride in groundwater. An area of about 1.5 km2 has benefited due to this dug well recharge system.

  20. [Estimation of urban non-point source pollution loading and its factor analysis in the Pearl River Delta].

    Science.gov (United States)

    Liao, Yi-Shan; Zhuo, Mu-Ning; Li, Ding-Qiang; Guo, Tai-Long

    2013-08-01

    In the Pearl Delta region, urban rivers have been seriously polluted, and the input of non-point source pollution materials, such as chemical oxygen demand (COD), into rivers cannot be neglected. During 2009-2010, the water qualities at eight different catchments in the Fenjiang River of Foshan city were monitored, and the COD loads for eight rivulet sewages were calculated in respect of different rainfall conditions. Interesting results were concluded in our paper. The rainfall and landuse type played important roles in the COD loading, with greater influence of rainfall than landuse type. Consequently, a COD loading formula was constructed that was defined as a function of runoff and landuse type that were derived SCS model and land use map. Loading of COD could be evaluated and predicted with the constructed formula. The mean simulation accuracy for single rainfall event was 75.51%. Long-term simulation accuracy was better than that of single rainfall. In 2009, the estimated COD loading and its loading intensity were 8 053 t and 339 kg x (hm2 x a)(-1), and the industrial land was regarded as the main source of COD pollution area. The severe non-point source pollution such as COD in Fenjiang River must be paid more attention in the future.

  1. Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

    Science.gov (United States)

    Woronowicz, Michael

    2016-01-01

    Analytical expressions for column number density (CND) are developed for optical line of sight paths through a variety of steady free molecule point source models including directionally-constrained effusion (Mach number M = 0) and flow from a sonic orifice (M = 1). Sonic orifice solutions are approximate, developed using a fair simulacrum fitted to the free molecule solution. Expressions are also developed for a spherically-symmetric thermal expansion (M = 0). CND solutions are found for the most general paths relative to these sources and briefly explored. It is determined that the maximum CND from a distant location through directed effusion and sonic orifice cases occurs along the path parallel to the source plane that intersects the plume axis. For the effusive case this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plume's axis. For sonic plumes this ratio is reduced to about 4/3. For high Mach number cases the maximum CND will be found along the axial centerline path. Keywords: column number density, plume flows, outgassing, free molecule flow.

  2. Monte Carlo simulation of scatter in non-uniform symmetrical attenuating media for point and distributed sources

    International Nuclear Information System (INIS)

    Henry, L.J.; Rosenthal, M.S.

    1992-01-01

    We report results of scatter simulations for both point and distributed sources of 99m Tc in symmetrical non-uniform attenuating media. The simulations utilized Monte Carlo techniques and were tested against experimental phantoms. Both point and ring sources were used inside a 10.5 cm radius acrylic phantom. Attenuating media consisted of combinations of water, ground beef (to simulate muscle mass), air and bone meal (to simulate bone mass). We estimated/measured energy spectra, detector efficiencies and peak height ratios for all cases. In all cases, the simulated spectra agree with the experimentally measured spectra within 2 SD. Detector efficiencies and peak height ratios also are in agreement. The Monte Carlo code is able to properly model the non-uniform attenuating media used in this project. With verification of the simulations, it is possible to perform initial evaluation studies of scatter correction algorithms by evaluating the mechanisms of action of the correction algorithm on the simulated spectra where the magnitude and sources of scatter are known. (author)

  3. CHANDRA ACIS SURVEY OF X-RAY POINT SOURCES IN NEARBY GALAXIES. II. X-RAY LUMINOSITY FUNCTIONS AND ULTRALUMINOUS X-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Song; Qiu, Yanli; Liu, Jifeng [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Bregman, Joel N., E-mail: songw@bao.ac.cn, E-mail: jfliu@bao.ac.cn [University of Michigan, Ann Arbor, MI 48109 (United States)

    2016-09-20

    Based on the recently completed Chandra /ACIS survey of X-ray point sources in nearby galaxies, we study the X-ray luminosity functions (XLFs) for X-ray point sources in different types of galaxies and the statistical properties of ultraluminous X-ray sources (ULXs). Uniform procedures are developed to compute the detection threshold, to estimate the foreground/background contamination, and to calculate the XLFs for individual galaxies and groups of galaxies, resulting in an XLF library of 343 galaxies of different types. With the large number of surveyed galaxies, we have studied the XLFs and ULX properties across different host galaxy types, and confirm with good statistics that the XLF slope flattens from lenticular ( α ∼ 1.50 ± 0.07) to elliptical (∼1.21 ± 0.02), to spirals (∼0.80 ± 0.02), to peculiars (∼0.55 ± 0.30), and to irregulars (∼0.26 ± 0.10). The XLF break dividing the neutron star and black hole binaries is also confirmed, albeit at quite different break luminosities for different types of galaxies. A radial dependency is found for ellipticals, with a flatter XLF slope for sources located between D {sub 25} and 2 D {sub 25}, suggesting the XLF slopes in the outer region of early-type galaxies are dominated by low-mass X-ray binaries in globular clusters. This study shows that the ULX rate in early-type galaxies is 0.24 ± 0.05 ULXs per surveyed galaxy, on a 5 σ confidence level. The XLF for ULXs in late-type galaxies extends smoothly until it drops abruptly around 4 × 10{sup 40} erg s{sup −1}, and this break may suggest a mild boundary between the stellar black hole population possibly including 30 M {sub ⊙} black holes with super-Eddington radiation and intermediate mass black holes.

  4. An open, interoperable, transdisciplinary approach to a point cloud data service using OGC standards and open source software.

    Science.gov (United States)

    Steer, Adam; Trenham, Claire; Druken, Kelsey; Evans, Benjamin; Wyborn, Lesley

    2017-04-01

    High resolution point clouds and other topology-free point data sources are widely utilised for research, management and planning activities. A key goal for research and management users is making these data and common derivatives available in a way which is seamlessly interoperable with other observed and modelled data. The Australian National Computational Infrastructure (NCI) stores point data from a range of disciplines, including terrestrial and airborne LiDAR surveys, 3D photogrammetry, airborne and ground-based geophysical observations, bathymetric observations and 4D marine tracers. These data are stored alongside a significant store of Earth systems data including climate and weather, ecology, hydrology, geoscience and satellite observations, and available from NCI's National Environmental Research Data Interoperability Platform (NERDIP) [1]. Because of the NERDIP requirement for interoperability with gridded datasets, the data models required to store these data may not conform to the LAS/LAZ format - the widely accepted community standard for point data storage and transfer. The goal for NCI is making point data discoverable, accessible and useable in ways which allow seamless integration with earth observation datasets and model outputs - in turn assisting researchers and decision-makers in the often-convoluted process of handling and analyzing massive point datasets. With a use-case of providing a web data service and supporting a derived product workflow, NCI has implemented and tested a web-based point cloud service using the Open Geospatial Consortium (OGC) Web Processing Service [2] as a transaction handler between a web-based client and server-side computing tools based on a native Linux operating system. Using this model, the underlying toolset for driving a data service is flexible and can take advantage of NCI's highly scalable research cloud. Present work focusses on the Point Data Abstraction Library (PDAL) [3] as a logical choice for

  5. Quantification of Greenhouse Gas Emission Rates from strong Point Sources by Airborne IPDA-Lidar Measurements: Methodology and Experimental Results

    Science.gov (United States)

    Ehret, G.; Amediek, A.; Wirth, M.; Fix, A.; Kiemle, C.; Quatrevalet, M.

    2016-12-01

    We report on a new method and on the first demonstration to quantify emission rates from strong greenhouse gas (GHG) point sources using airborne Integrated Path Differential Absorption (IPDA) Lidar measurements. In order to build trust in the self-reported emission rates by countries, verification against independent monitoring systems is a prerequisite to check the reported budget. A significant fraction of the total anthropogenic emission of CO2 and CH4 originates from localized strong point sources of large energy production sites or landfills. Both are not monitored with sufficiently accuracy by the current observation system. There is a debate whether airborne remote sensing could fill in the gap to infer those emission rates from budgeting or from Gaussian plume inversion approaches, whereby measurements of the GHG column abundance beneath the aircraft can be used to constrain inverse models. In contrast to passive sensors, the use of an active instrument like CHARM-F for such emission verification measurements is new. CHARM-F is a new airborne IPDA-Lidar devised for the German research aircraft HALO for the simultaneous measurement of the column-integrated dry-air mixing ratio of CO2 and CH4 commonly denoted as XCO2 und XCH4, respectively. It has successfully been tested in a serious of flights over Central Europe to assess its performance under various reflectivity conditions and in a strongly varying topography like the Alps. The analysis of a methane plume measured in crosswind direction of a coal mine ventilation shaft revealed an instantaneous emission rate of 9.9 ± 1.7 kt CH4 yr-1. We discuss the methodology of our point source estimation approach and give an outlook on the CoMet field experiment scheduled in 2017 for the measurement of anthropogenic and natural GHG emissions by a combination of active and passive remote sensing instruments on research aircraft.

  6. Large Industrial Point Sources in Italy: a focus on mercury concentrations resulting from three seasonal ship-borne measurements

    Directory of Open Access Journals (Sweden)

    Bencardino M.

    2013-04-01

    Full Text Available In Italy there are 25 Large Industrial Point Sources whose mercury emissions in air exceed the established threshold of 10 kg year−1. Many of these mercury point sources, mostly distributed along the Italian coastal area, are located at sites qualified as National Interest Rehabilitation Sites because of documented contamination in qualitative and/or quantitative terms and of potential health impact. Atmospheric mercury emissions related to Italian Large Industrial Point Sources, with a value of 1.04 Mg·yr−1 for 2007, have a not negligible contribution, accounting, on their own, for more than 10% of the total mercury emissions resulting from all activity sectors at a national level. Among others, thermal power stations, pig iron and steel as well as basic inorganic chemical production, result to be the main contributing industrial activities. In order to assess how mercury species concentrations and distribution in the Marine Boundary Layer (MBL change with vicinity to large industrial sites, measurements of atmospheric mercury were performed during three oceanographic campaigns aboard the Research Vessel (R.V. Urania of the Italian CNR. Collection of GEM, GOM and PBM was conducted across the Adriatic sea, during autumn 2004 (27th of October to 12th of November and summer 2005 (17th to 29th of June, and across the Tyrrhenian sea during autumn 2007 (12th of September to 1st October. Analysis were carried out with reference to the period in which the R.V. Urania has stopped close to the main Italian industrial contaminated sites. Explorative statistical parameters of atmospheric mercury species were computed over each single stop-period and then compared with the overall cruise campaign measurements. Results are herein presented and discussed.

  7. Search for cosmic γ-point sources above 20 TeV with the HEGRA detector fields

    International Nuclear Information System (INIS)

    Prahl, J.

    1999-01-01

    The topic of this thesis is the search for point sources of high energy γ-rays (above 20 TeV) during the time interval from December 1993 until September 1995 with the HEGRA scintillator and AIROBICC arrays. The main aim is to exploit the available data as complete as possible in order to achieve a maximum in sensitivity. A thorough MtCarlo simulation of the registered events from the cosmic-ray-induced air showers allows for the use of all acquired events [de

  8. DISCRIMINATION OF NATURAL AND NON-POINT SOURCE EFFECTS FROM ANTHROGENIC EFFECTS AS REFLECTED IN BENTHIC STATE IN THREE ESTUARIES IN NEW ENGLAND

    Science.gov (United States)

    In order to protect estuarine resources, managers must be able to discern the effects of natural conditions and non-point source effects, and separate them from multiple anthropogenic point source effects. Our approach was to evaluate benthic community assemblages, riverine nitro...

  9. Research on numerical method for multiple pollution source discharge and optimal reduction program

    Science.gov (United States)

    Li, Mingchang; Dai, Mingxin; Zhou, Bin; Zou, Bin

    2018-03-01

    In this paper, the optimal method for reduction program is proposed by the nonlinear optimal algorithms named that genetic algorithm. The four main rivers in Jiangsu province, China are selected for reducing the environmental pollution in nearshore district. Dissolved inorganic nitrogen (DIN) is studied as the only pollutant. The environmental status and standard in the nearshore district is used to reduce the discharge of multiple river pollutant. The research results of reduction program are the basis of marine environmental management.

  10. Considering a point-source in a regional air pollution model; Prise en compte d`une source ponctuelle dans un modele regional de pollution atmospherique

    Energy Technology Data Exchange (ETDEWEB)

    Lipphardt, M.

    1997-06-19

    This thesis deals with the development and validation of a point-source plume model, with the aim to refine the representation of intensive point-source emissions in regional-scale air quality models. The plume is modelled at four levels of increasing complexity, from a modified Gaussian plume model to the Freiberg and Lusis ring model. Plume elevation is determined by Netterville`s plume rise model, using turbulence and atmospheric stability parameters. A model for the effect of a fine-scale turbulence on the mean concentrations in the plume is developed and integrated in the ring model. A comparison between results with and without considering micro-mixing shows the importance of this effect in a chemically reactive plume. The plume model is integrated into the Eulerian transport/chemistry model AIRQUAL, using an interface between Airqual and the sub-model, and interactions between the two scales are described. A simulation of an air pollution episode over Paris is carried out, showing that the utilization of such a sub-scale model improves the accuracy of the air quality model

  11. Analysis of point source pollution and water environmental quality variation trends in the Nansi Lake basin from 2002 to 2012.

    Science.gov (United States)

    Wang, Weiliang; Liu, Xiaohui; Wang, Yufan; Guo, Xiaochun; Lu, Shaoyong

    2016-03-01

    Based on the data analysis of the water environmental quality and economic development from 2002 to 2012 in the Nansi Lake basin, the correlation and change between the water environmental quality and economic development were studied. Results showed that the GDP and wastewater emissions of point source in the Nansi Lake basin had an average annual growth of 7.30 and 7.68 %, respectively, from 2002 to 2012. The emissions of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) had the average annual decrease of 7.69 and 6.79 % in 2012, respectively, compared to 2002. Basin water quality overall improved, reaching the Class III of the "Environmental quality standards for surface water (GB3838-2002)," in which the main reason was that sewage treatment rate increased gradually and was above 90 % in 2012 (an increase of 10 % compared to 2002) with the progress of pollution abatement technology and the implementation of relevant policies and regulations. The contribution of water environmental pollution was analyzed from related cities (Ji'ning, Zaozhuang, Heze). Results indicated that Ji'ning had the largest contribution to water pollution of the Nansi Lake basin, and the pollutant from domestic sources accounted for a higher percentage compared to industrial sources. The wastewater, COD, and NH3-N mainly came from mining and washing of coal, manufacture of raw chemical materials and chemical products, papermaking industry, and food processing industry. According to the water pollution characteristics of the Nansi Lake basin, the basin pollution treatment strategy and prevention and treatment system were dissected to provide a scientific basis for prevention and control of lakeside point source pollution along the Nansi Lake.

  12. Active AirCore Sampling: Constraining Point Sources of Methane and Other Gases with Fixed Wing Unmanned Aerial Systems

    Science.gov (United States)

    Bent, J. D.; Sweeney, C.; Tans, P. P.; Newberger, T.; Higgs, J. A.; Wolter, S.

    2017-12-01

    Accurate estimates of point source gas emissions are essential for reconciling top-down and bottom-up greenhouse gas measurements, but sampling such sources is challenging. Remote sensing methods are limited by resolution and cloud cover; aircraft methods are limited by air traffic control clearances, and the need to properly determine boundary layer height. A new sampling approach leverages the ability of unmanned aerial systems (UAS) to measure all the way to the surface near the source of emissions, improving sample resolution, and reducing the need to characterize a wide downstream swath, or measure to the full height of the planetary boundary layer (PBL). The "Active-AirCore" sampler, currently under development, will fly on a fixed wing UAS in Class G airspace, spiraling from the surface to 1200 ft AGL around point sources such as leaking oil wells to measure methane, carbon dioxide and carbon monoxide. The sampler collects a 100-meter long sample "core" of air in an 1/8" passivated stainless steel tube. This "core" is run on a high-precision instrument shortly after the UAS is recovered. Sample values are mapped to a specific geographic location by cross-referencing GPS and flow/pressure metadata, and fluxes are quantified by applying Gauss's theorem to the data, mapped onto the spatial "cylinder" circumscribed by the UAS. The AirCore-Active builds off the sampling ability and analytical approach of the related AirCore sampler, which profiles the atmosphere passively using a balloon launch platform, but will add an active pumping capability needed for near-surface horizontal sampling applications. Here, we show design elements, laboratory and field test results for methane, describe the overall goals of the mission, and discuss how the platform can be adapted, with minimal effort, to measure other gas species.

  13. Economic gains fromtargeted measures related to non-point pollution in agriculture based on detailed nitrate reduction maps

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.; Hansen, Anne Lausten

    2016-01-01

    From 1990 to 2003, Denmark reduced N-leaching from the root zone by 50%. However, more measures are required, and in recent years, the focus has been on how to differentiate measures in order to ensure that they are implemented where the effect on N-loss reductions per ha is the greatest. The pur...

  14. Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

    DEFF Research Database (Denmark)

    Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-so......-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

  15. Analysis of the environmental behavior of farmers for non-point source pollution control and management in a water source protection area in China.

    Science.gov (United States)

    Wang, Yandong; Yang, Jun; Liang, Jiping; Qiang, Yanfang; Fang, Shanqi; Gao, Minxue; Fan, Xiaoyu; Yang, Gaihe; Zhang, Baowen; Feng, Yongzhong

    2018-08-15

    The environmental behavior of farmers plays an important role in exploring the causes of non-point source pollution and taking scientific control and management measures. Based on the theory of planned behavior (TPB), the present study investigated the environmental behavior of farmers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China. Results showed that TPB could explain farmers' environmental behavior (SMC=0.26) and intention (SMC=0.36) well. Furthermore, the farmers' attitude towards behavior (AB), subjective norm (SN), and perceived behavioral control (PBC) positively and significantly influenced their environmental intention; their environmental intention further impacted their behavior. SN was proved to be the main key factor indirectly influencing the farmers' environmental behavior, while PBC had no significant and direct effect. Moreover, environmental knowledge following as a moderator, gender and age was used as control variables to conduct the environmental knowledge on TPB construct moderated mediation analysis. It demonstrated that gender had a significant controlling effect on environmental behavior; that is, males engage in more environmentally friendly behaviors. However, age showed a significant negative controlling effect on pro-environmental intention and an opposite effect on pro-environmental behavior. In addition, environmental knowledge could negatively moderate the relationship between PBC and environmental intention. PBC had a greater impact on the environmental intention of farmers with poor environmental knowledge, compared to those with plenty environmental knowledge. Altogether, the present study could provide a theoretical basis for non-point source pollution control and management. Copyright © 2018 Elsevier B.V. All rights reserved.

  16. Prediction of boiling points of some organic compounds to be used in volume reduction of liquid radioactive wastes

    International Nuclear Information System (INIS)

    Helal, N.L.; Ezz el-Din, M.R.

    2004-01-01

    Boiling points determination may help in the evaporation process used to solidify high-level liquid wastes and to reduce the volume of wastes that require disposal. The problem that always encountered is how to choose an appropriate method to determine the boiling points of the liquid wastes which will be able to solve. We introduce this work with the aim to use mathematical descriptors and their applications in predicting boiling points essential for the evaporation process. This work was applied for diverse database of two sets of chemicals that may exist in radioactive wastes. The first set was 59 alcohols and amines (group a) and the second was 11 aniline compounds (group b). The results show that the used mathematical descriptors give a reasonable predictive model for the diverse sets of molecules

  17. Identification of a time-varying point source in a system of two coupled linear diffusion-advection- reaction equations: application to surface water pollution

    International Nuclear Information System (INIS)

    Hamdi, Adel

    2009-01-01

    This paper deals with the identification of a point source (localization of its position and recovering the history of its time-varying intensity function) that constitutes the right-hand side of the first equation in a system of two coupled 1D linear transport equations. Assuming that the source intensity function vanishes before reaching the final control time, we prove the identifiability of the sought point source from recording the state relative to the second coupled transport equation at two observation points framing the source region. Note that at least one of the two observation points should be strategic. We establish an identification method that uses these records to identify the source position as the root of a continuous and strictly monotonic function. Whereas the source intensity function is recovered using a recursive formula without any need of an iterative process. Some numerical experiments on a variant of the surface water pollution BOD–OD coupled model are presented

  18. Attenuation data of point isotropic neutron sources up to 400MeV in water, ordinary concrete and iron

    Energy Technology Data Exchange (ETDEWEB)

    Kotegawa, Hiroshi; Tanaka, Shun-ichi; Sakamoto, Yukio; Nakane, Yoshihiro; Nakashima, Hiroshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1994-08-01

    A comprehensive attenuation data of dose equivalent for point isotropic monoenergetic neutron sources up to 400MeV in infinite shields of water, ordinary concrete and iron has been calculated using the ANISN-JR code and a neutron-photon multigroup macroscopic cross section HIL086R. The attenuation factors were fitted to a 4th order polynomial exponent formula, making possible to use easily for point kernel codes. Additional data in finite shielding geometry was also calculated to correct the effect due to infinite medium, giving the maximum correction of 0.23 in the region for more 400 cm distance from neutron source of 400 MeV in iron shield. Effective attenuation length for monoenergetic neutrons have been studied in detail. Subsequently, it was shown that the attenuation length was strongly dependent upon the penetration length and the Moyer`s formula using a single attenuation length brought large error into the dose estimation behind thick shields for the intermediate energy neutrons up to 400 MeV. Furthermore, it was demonstrated that there was difference more than 50 % in the attenuation length of iron between the calculations with HIL086R and HIL086 because of the self-shielding effect. (author).

  19. DrSPINE - New approach to data reduction and analysis for neutron spin echo experiments from pulsed and reactor sources

    International Nuclear Information System (INIS)

    Zolnierczuk, P.A.; Ohl, M.; Holderer, O.; Monkenbusch, M.

    2015-01-01

    Neutron spin echo (NSE) method at a pulsed neutron source presents new challenges to the data reduction and analysis as compared to the instruments installed at reactor sources. The main advantage of the pulsed source NSE is the ability to resolve the neutron wavelength and collect neutrons over a wider bandwidth. This allows us to more precisely determine the symmetry phase and measure the data for several Q-values at the same time. Based on the experience gained at the SNS NSE - the first, and to date the only one, NSE instrument installed at a pulsed spallation source, we propose a novel and unified approach to the NSE data processing called DrSPINE. The goals of the DrSPINE project are: -) exploit better symmetry phase determination due to the broader bandwidth at a pulsed source; -) take advantage of larger Q coverage for TOF instruments; -) use objective statistical criteria to get the echo fits right; -) provide robust reduction with report generation; -) incorporate absolute instrument calibration; and -) allow for background subtraction. The software must be able to read the data from various instruments, perform data integrity, consistency and compatibility checks and combine the data from compatible sets, partial scans, etc. We chose to provide a console-based interface with the ability to process macros (scripts) for batch evaluation. And last and not the least, a good software package has to provide adequate documentation. DrSPINE software is currently under development

  20. Breast cancer prevention knowledge, beliefs, and information sources between non-Hispanic and Hispanic college women for risk reduction focus.

    Science.gov (United States)

    Kratzke, Cynthia; Amatya, Anup; Vilchis, Hugo

    2015-02-01

    Although growing research focuses on breast cancer screenings, little is known about breast cancer prevention with risk reduction awareness for ethnic differences among college-age women. This study examined breast cancer prevention knowledge, beliefs, and information sources between non-Hispanic and Hispanic college women. Using a cross-sectional study, women at a university in the Southwest completed a 51-item survey about breast cancer risk factors, beliefs, and media and interpersonal information sources. The study was guided by McGuire's Input Output Persuasion Model. Of the 546 participants, non-Hispanic college women (n = 277) and Hispanic college women (n = 269) reported similar basic knowledge levels of modifiable breast cancer risk factors for alcohol consumption (52 %), obesity (72 %), childbearing after age 35 (63 %), and menopausal hormone therapy (68 %) using bivariate analyses. Most common information sources were Internet (75 %), magazines (69 %), provider (76 %) and friends (61 %). Least common sources were radio (44 %), newspapers (34 %), and mothers (36 %). Non-Hispanic college women with breast cancer family history were more likely to receive information from providers, friends, and mothers. Hispanic college women with a breast cancer family history were more likely to receive information from their mothers. Breast cancer prevention education for college women is needed to include risk reduction for modifiable health behavior changes as a new focus. Health professionals may target college women with more information sources including the Internet or apps.

  1. The XMM-SERVS survey: new XMM-Newton point-source catalog for the XMM-LSS field

    Science.gov (United States)

    Chen, C.-T. J.; Brandt, W. N.; Luo, B.; Ranalli, P.; Yang, G.; Alexander, D. M.; Bauer, F. E.; Kelson, D. D.; Lacy, M.; Nyland, K.; Tozzi, P.; Vito, F.; Cirasuolo, M.; Gilli, R.; Jarvis, M. J.; Lehmer, B. D.; Paolillo, M.; Schneider, D. P.; Shemmer, O.; Smail, I.; Sun, M.; Tanaka, M.; Vaccari, M.; Vignali, C.; Xue, Y. Q.; Banerji, M.; Chow, K. E.; Häußler, B.; Norris, R. P.; Silverman, J. D.; Trump, J. R.

    2018-04-01

    We present an X-ray point-source catalog from the XMM-Large Scale Structure survey region (XMM-LSS), one of the XMM-Spitzer Extragalactic Representative Volume Survey (XMM-SERVS) fields. We target the XMM-LSS region with 1.3 Ms of new XMM-Newton AO-15 observations, transforming the archival X-ray coverage in this region into a 5.3 deg2 contiguous field with uniform X-ray coverage totaling 2.7 Ms of flare-filtered exposure, with a 46 ks median PN exposure time. We provide an X-ray catalog of 5242 sources detected in the soft (0.5-2 keV), hard (2-10 keV), and/or full (0.5-10 keV) bands with a 1% expected spurious fraction determined from simulations. A total of 2381 new X-ray sources are detected compared to previous source catalogs in the same area. Our survey has flux limits of 1.7 × 10-15, 1.3 × 10-14, and 6.5 × 10-15 erg cm-2 s-1 over 90% of its area in the soft, hard, and full bands, respectively, which is comparable to those of the XMM-COSMOS survey. We identify multiwavelength counterpart candidates for 99.9% of the X-ray sources, of which 93% are considered as reliable based on their matching likelihood ratios. The reliabilities of these high-likelihood-ratio counterparts are further confirmed to be ≈97% reliable based on deep Chandra coverage over ≈5% of the XMM-LSS region. Results of multiwavelength identifications are also included in the source catalog, along with basic optical-to-infrared photometry and spectroscopic redshifts from publicly available surveys. We compute photometric redshifts for X-ray sources in 4.5 deg2 of our field where forced-aperture multi-band photometry is available; >70% of the X-ray sources in this subfield have either spectroscopic or high-quality photometric redshifts.

  2. Global threat reduction initiative efforts to address transportation challenges associated with the recovery of disused radioactive sealed sources - 10460

    International Nuclear Information System (INIS)

    Whitworth, Julie; Abeyta, Cristy L.; Griffin, Justin M.; Matzke, James L.; Pearson, Michael W.; Cuthbertson, Abigail; Rawl, Richard; Singley, Paul

    2010-01-01

    Proper disposition of disused radioactive sources is essential for their safe and secure management and necessary to preclude their use in malicious activities. Without affordable, timely transportation options, disused sealed sources remain in storage at hundreds of sites throughout the country and around the world. While secure storage is a temporary measure, the longer sources remain disused or unwanted the chances increase that they will become unsecured or abandoned. The Global Threat Reduction Initiative's Off-Site Source Recovery Project (GTRIlOSRP), recovers thousands of disused and unwanted sealed sources annually as part of GTRl's larger mission to reduce and protect high risk nuclear and radiological materials located at civilian sites worldwide. Faced with decreasing availability of certified transportation containers to support movement of disused and unwanted neutron- and beta/gamma-emitting radioactive sealed sources, GTRIlOSRP has initiated actions to ensure the continued success of the project in timely recovery and management of sealed radioactive sources. Efforts described in this paper to enhance transportation capabilities include: (sm b ullet) Addition of authorized content to existing and planned Type B containers to support the movement of non-special form and other Type B-quantity sealed sources; (sm b ullet) Procurement of vendor services for the design, development, testing and certification of a new Type B container to support transportation of irradiators, teletherapy heads or sources removed from these devices using remote handling capabilities such as the IAEA portable hot cell facility; (sm b ullet) Expansion of shielded Type A container inventory for transportation of gamma-emitting sources in activity ranges requiring use of shielding for conformity with transportation requirements; (sm b ullet) Approval of the S300 Type A fissile container for transport of Pu-239 sealed sources internationally; (sm b ullet) Technology transfer of

  3. Diffusion from a Ground Level Point Source Experiment with Thermoluminescence Dosimeters and Kr 85 as Tracer Substance

    Energy Technology Data Exchange (ETDEWEB)

    Gyllander, Ch; Hollman, S; Widemo, U

    1969-04-15

    Within the framework of the IRIS-project (Iodine Research in Safety Project) an experiment to study diffusion at near-ground level was carried out on 19 December 1967 using {sup 85}Kr as the tracer element. The object of the experiment was a) to test the method using |3-sensitive thermoluminescence dosimeters under actual field conditions. b) to study the initial dilution from a ground level point source. The test area chosen was the Tranvik valley just south of Trobbofjaerden, an inland bay of the Baltic. Dose distributions have been studied at two sections, 50 and 200 m respectively, from the release point. At each level various dispersion parameters have been experimentally determined and their conformity to normal distribution have been calculated. Dilution factors valid for the centre of the plume are related to the values reported in the literature. The experiment was made under ideal weather conditions above snow-free ground. Results of the next experiment, a point release at ground level from a building at Studsvik, are expected to yield valuable information concerning the effect of buildings on the diffusion pattern.

  4. Point kinetics equations for subcritical systems based on the importance function associated to an external neutron source

    International Nuclear Information System (INIS)

    Carvalho Gonçalves, Wemerson de; Martinez, Aquilino Senra; Carvalho da Silva, Fernando

    2015-01-01

    Highlights: • We define the new function importance. • We calculate the kinetic parameters Λ, β, Γ and Q to: 0.95, 0.96, 0.97, 0.98 and 0.99. • We compared the results with those obtained by the main important functions. • We found that the calculated kinetic parameters are physically consistent. - Abstract: This paper aims to determine the parameters for a new set of equations of point kinetic subcritical systems, based on the concept of importance of Heuristic Generalized Perturbation Theory (HGPT). The importance function defined here is related to both the subcriticality and the external neutron source worth (which keeps the system at steady state). The kinetic parameters defined in this work are compared with the corresponding parameters when adopting the importance functions proposed by Gandini and Salvatores (2002), Dulla et al. (2006) and Nishihara et al. (2003). Furthermore, the point kinetics equations developed here are solved for two different transients, considering the parameters obtained with different importance functions. The results collected show that there is a similar behavior of the solution of the point kinetics equations, when used with the parameters obtained by the importance functions proposed by Gandini and Salvatores (2002) and Dulla et al. (2006), specially near the criticality. However, this is not verified as the system gets farther from criticality

  5. Diffusion from a Ground Level Point Source Experiment with Thermoluminescence Dosimeters and Kr 85 as Tracer Substance

    International Nuclear Information System (INIS)

    Gyllander, Ch.; Hollman, S.; Widemo, U.

    1969-04-01

    Within the framework of the IRIS-project (Iodine Research in Safety Project) an experiment to study diffusion at near-ground level was carried out on 19 December 1967 using 85 Kr as the tracer element. The object of the experiment was a) to test the method using |3-sensitive thermoluminescence dosimeters under actual field conditions. b) to study the initial dilution from a ground level point source. The test area chosen was the Tranvik valley just south of Trobbofjaerden, an inland bay of the Baltic. Dose distributions have been studied at two sections, 50 and 200 m respectively, from the release point. At each level various dispersion parameters have been experimentally determined and their conformity to normal distribution have been calculated. Dilution factors valid for the centre of the plume are related to the values reported in the literature. The experiment was made under ideal weather conditions above snow-free ground. Results of the next experiment, a point release at ground level from a building at Studsvik, are expected to yield valuable information concerning the effect of buildings on the diffusion pattern

  6. Screening the Medicines for Malaria Venture Pathogen Box across Multiple Pathogens Reclassifies Starting Points for Open-Source Drug Discovery.

    Science.gov (United States)

    Duffy, Sandra; Sykes, Melissa L; Jones, Amy J; Shelper, Todd B; Simpson, Moana; Lang, Rebecca; Poulsen, Sally-Ann; Sleebs, Brad E; Avery, Vicky M

    2017-09-01

    Open-access drug discovery provides a substantial resource for diseases primarily affecting the poor and disadvantaged. The open-access Pathogen Box collection is comprised of compounds with demonstrated biological activity against specific pathogenic organisms. The supply of this resource by the Medicines for Malaria Venture has the potential to provide new chemical starting points for a number of tropical and neglected diseases, through repurposing of these compounds for use in drug discovery campaigns for these additional pathogens. We tested the Pathogen Box against kinetoplastid parasites and malaria life cycle stages in vitro Consequently, chemical starting points for malaria, human African trypanosomiasis, Chagas disease, and leishmaniasis drug discovery efforts have been identified. Inclusive of this in vitro biological evaluation, outcomes from extensive literature reviews and database searches are provided. This information encompasses commercial availability, literature reference citations, other aliases and ChEMBL number with associated biological activity, where available. The release of this new data for the Pathogen Box collection into the public domain will aid the open-source model of drug discovery. Importantly, this will provide novel chemical starting points for drug discovery and target identification in tropical disease research. Copyright © 2017 Duffy et al.

  7. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Erin K. Field; Robin Gerlach; Sridhar Viamajala; Laura K. Jennings; Alfred B. Cunningham; Brent M. Peyton; William A. Apel

    2011-09-01

    The reduction of hexavalent chromium, Cr(VI), to trivalent chromium, Cr(III), can be an important aspect of remediation processes at Department of Energy (DOE) and other contaminated sites. Cellulomonas species are found at several Cr(VI) contaminated and uncontaminated locations at the DOE site in Hanford, Washington. Members of this genus have demonstrated the ability to effectively reduce Cr(VI) to Cr(III) fermentatively and therefore play a potential role in hexavalent chromium remediation at this site. Batch studies were conducted with Cellulomonas sp. strain ES6 to assess the influence of various carbon sources, iron minerals, and electron shuttling compounds on Cr(VI) reduction. These chemical species are likely to be present in these terrestrial environments during in situ bioremediation. Results indicated that there were a number of interactions between these compounds that influenced Cr(VI) reduction rates. The type of carbon source as well as the type of electron shuttle present influenced Cr(VI) reduction rates. When an electron shuttle, such as anthraquinone-2,6-disulfonate (AQDS), was present in the system, reduction rates increased significantly. Biologically reduced AQDS (AHDS) reduced Cr(VI) almost instantaneously. The presence of iron minerals and their concentrations did not significantly influence Cr(VI) reduction rates. However, strain ES6 or AQDS could directly reduce surface-associated Fe(III) to Fe(II) which was capable of reducing Cr(VI) at a near instantaneous rate. These results suggest the rate limiting step in these systems is the transfer of electrons from strain ES6 to the intermediate or terminal electron acceptor whether that is Cr(VI), Fe(III), or AQDS.

  8. Influence of Carbon Sources and Electron Shuttles on Ferric Iron Reduction by Cellulomonas sp. Strain ES6

    Energy Technology Data Exchange (ETDEWEB)

    Dr Robin Gerlach; Erin K. Field; Sridhar Viamajala; Brent M. Peyton; William A. Apel; Al B. Cunningham

    2011-09-01

    Microbially reduced iron minerals can reductively transform a variety of contaminants including heavy metals, radionuclides, chlorinated aliphatics, and nitroaromatics. A number of Cellulomonas spp. strains, including strain ES6, isolated from aquifer samples obtained at the U.S. Department of Energy's Hanford site in Washington, have been shown to be capable of reducing Cr(VI), TNT, natural organic matter, and soluble ferric iron [Fe(III)]. This research investigated the ability of Cellulomonas sp. strain ES6 to reduce solid phase and dissolved Fe(III) utilizing different carbon sources and various electron shuttling compounds. Results suggest that Fe(III) reduction by and growth of strain ES6 was dependent upon the type of electron donor, the form of iron present, and the presence of synthetic or natural organic matter, such as anthraquinone-2,6-disulfonate (AQDS) or humic substances. This research suggests that Cellulomonas sp. strain ES6 could play a significant role in metal reduction in the Hanford subsurface and that the choice of carbon source and organic matter addition can allow for independent control of growth and iron reduction activity.

  9. Cr(Vi) reduction capacity of activated sludge as affected by nitrogen and carbon sources, microbial acclimation and cell multiplication

    International Nuclear Information System (INIS)

    Ferro Orozco, A.M.; Contreras, E.M.; Zaritzky, N.E.

    2010-01-01

    The objectives of the present work were: (i) to analyze the capacity of activated sludge to reduce hexavalent chromium using different carbon sources as electron donors in batch reactors, (ii) to determine the relationship between biomass growth and the amount of Cr(VI) reduced considering the effect of the nitrogen to carbon source ratio, and (iii) to determine the effect of the Cr(VI) acclimation stage on the performance of the biological chromium reduction assessing the stability of the Cr(VI) reduction capacity of the activated sludge. The highest specific Cr(VI) removal rate (q Cr ) was attained with cheese whey or lactose as electron donors decreasing in the following order: cheese whey ∼ lactose > glucose > citrate > acetate. Batch assays with different nitrogen to carbon source ratio demonstrated that biological Cr(VI) reduction is associated to the cell multiplication phase; as a result, maximum Cr(VI) removal rates occur when there is no substrate limitation. The biomass can be acclimated to the presence of Cr(VI) and generate new cells that maintain the ability to reduce chromate. Therefore, the activated sludge process could be applied to a continuous Cr(VI) removal process.

  10. Implementation of variance-reduction techniques for Monte Carlo nuclear logging calculations with neutron sources

    NARCIS (Netherlands)

    Maucec, M

    2005-01-01

    Monte Carlo simulations for nuclear logging applications are considered to be highly demanding transport problems. In this paper, the implementation of weight-window variance reduction schemes in a 'manual' fashion to improve the efficiency of calculations for a neutron logging tool is presented.

  11. Study of landscape patterns of variation and optimization based on non-point source pollution control in an estuary.

    Science.gov (United States)

    Jiang, Mengzhen; Chen, Haiying; Chen, Qinghui; Wu, Haiyan

    2014-10-15

    Appropriate increases in the "sink" of a landscape can reduce the risk of non-point source pollution (NPSP) to the sea at relatively lower costs and at a higher efficiency. Based on high-resolution remote sensing image data taken between 2003 and 2008, we analyzed the "source" and "sink" landscape pattern variations of nitrogen and phosphorus pollutants in the Jiulongjiang estuary region. The contribution to the sea and distribution of each pollutant in the region was calculated using the LCI and mGLCI models. The results indicated that an increased amount of pollutants was contributed to the sea, and the "source" area of the nitrogen NPSP in the study area increased by 32.75 km(2). We also propose a landscape pattern optimization to reduce pollution in the Jiulongjiang estuary in 2008 through the conversion of cultivated land with slopes greater than 15° and paddy fields near rivers, and an increase in mangrove areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. VizieR Online Data Catalog: ChaMP X-ray point source catalog (Kim+, 2007)

    Science.gov (United States)

    Kim, M.; Kim, D.-W.; Wilkes, B. J.; Green, P. J.; Kim, E.; Anderson, C. S.; Barkhouse, W. A.; Evans, N. R.; Ivezic, Z.; Karovska, M.; Kashyap, V. L.; Lee, M. G.; Maksym, P.; Mossman, A. E.; Silverman, J. D.; Tananbaum, H. D.

    2009-01-01

    We present the Chandra Multiwavelength Project (ChaMP) X-ray point source catalog with ~6800 X-ray sources detected in 149 Chandra observations covering ~10deg2. The full ChaMP catalog sample is 7 times larger than the initial published ChaMP catalog. The exposure time of the fields in our sample ranges from 0.9 to 124ks, corresponding to a deepest X-ray flux limit of f0.5-8.0=9x10-16ergs/cm2/s. The ChaMP X-ray data have been uniformly reduced and analyzed with ChaMP-specific pipelines and then carefully validated by visual inspection. The ChaMP catalog includes X-ray photometric data in eight different energy bands as well as X-ray spectral hardness ratios and colors. To best utilize the ChaMP catalog, we also present the source reliability, detection probability, and positional uncertainty. (10 data files).

  13. REDUCTION IN ASTHMA MORBIDITY IN CHILDREN AS A RESULT OF HOME REMEDIATION AIMED AT MOISTURE SOURCES

    Science.gov (United States)

    Objective: Home dampness, presence of mold and allergens have been associated with asthma morbidity. We examined changes in asthma morbidity in children as a result of home remediation aimed at moisture sources.Design: Prospective, randomized controlled trial.Part...

  14. An improved export coefficient model to estimate non-point source phosphorus pollution risks under complex precipitation and terrain conditions.

    Science.gov (United States)

    Cheng, Xian; Chen, Liding; Sun, Ranhao; Jing, Yongcai

    2018-05-15

    To control non-point source (NPS) pollution, it is important to estimate NPS pollution exports and identify sources of pollution. Precipitation and terrain have large impacts on the export and transport of NPS pollutants. We established an improved export coefficient model (IECM) to estimate the amount of agricultural and rural NPS total phosphorus (TP) exported from the Luanhe River Basin (LRB) in northern China. The TP concentrations of rivers from 35 selected catchments in the LRB were used to test the model's explanation capacity and accuracy. The simulation results showed that, in 2013, the average TP export was 57.20 t at the catchment scale. The mean TP export intensity in the LRB was 289.40 kg/km 2 , which was much higher than those of other basins in China. In the LRB topographic regions, the TP export intensity was the highest in the south Yanshan Mountains and was followed by the plain area, the north Yanshan Mountains, and the Bashang Plateau. Among the three pollution categories, the contribution ratios to TP export were, from high to low, the rural population (59.44%), livestock husbandry (22.24%), and land-use types (18.32%). Among all ten pollution sources, the contribution ratios from the rural population (59.44%), pigs (14.40%), and arable land (10.52%) ranked as the top three sources. This study provides information that decision makers and planners can use to develop sustainable measures for the prevention and control of NPS pollution in semi-arid regions.

  15. DISSOLVED OXYGEN REDUCTION IN THE DIII-D NEUTRAL BEAM ION SOURCE COOLING SYSTEM

    International Nuclear Information System (INIS)

    YIP, H.; BUSATH, J.; HARRISON, S.

    2004-03-01

    OAK-B135 Neutral beam ion sources (NBIS) are critical components for the neutral beam injection system supporting the DIII-D tokamak. The NBIS must be cooled with 3028 (ell)/m (800 gpm) of de-ionized and de-oxygenated water to protect the sources from overheating and failure. These ions sources are currently irreplaceable. Since the water cooled molybdenum components will oxidize in water almost instantaneously in the presence of dissolved oxygen (DO), de-oxygenation is extremely important in the NBIS water system. Under normal beam operation the DO level is kept below 5 ppb. However, during weeknights and weekends when neutral beam is not in operation, the average DO level is maintained below 10 ppb by periodic circulation with a 74.6 kW (100 hp) pump, which consumes significant power. Experimental data indicated evidence of continuous oxygen diffusion through non-metallic hoses in the proximity of the NBIS. Because of the intermittent flow of the cooling water, the DO concentration at the ion source(s) could be even higher than measured downstream, and hence the concern of significant localized oxidation/corrosion. A new 3.73 kW (5 hp) auxiliary system, installed in the summer of 2003, is designed to significantly reduce the peak and the time-average DO levels in the water system and to consume only a fraction of the power

  16. The Reduction of Vertical Interchannel Crosstalk: The Analysis of Localisation Thresholds for Natural Sound Sources

    Directory of Open Access Journals (Sweden)

    Rory Wallis

    2017-03-01

    Full Text Available In subjective listening tests, natural sound sources were presented to subjects as vertically-oriented phantom images from two layers of loudspeakers, ‘height’ and ‘main’. Subjects were required to reduce the amplitude of the height layer until the position of the resultant sound source matched that of the same source presented from the main layer only (the localisation threshold. Delays of 0, 1 and 10 ms were applied to the height layer with respect to the main, with vertical stereophonic and quadraphonic conditions being tested. The results of the study showed that the localisation thresholds obtained were not significantly affected by sound source or presentation method. Instead, the only variable whose effect was significant was interchannel time difference (ICTD. For ICTD of 0 ms, the median threshold was −9.5 dB, which was significantly lower than the −7 dB found for both 1 and 10 ms. The results of the study have implications both for the recording of sound sources for three-dimensional (3D audio reproduction formats and also for the rendering of 3D images.

  17. Valuing the Potential Benefits of Water Quality Improvements in Watersheds Affected by Non-Point Source Pollution

    Directory of Open Access Journals (Sweden)

    Sergio Alvarez

    2016-03-01

    Full Text Available Nonpoint source (NPS pollution has been identified by the US Environmental Protection Agency (EPA as “the nation’s largest water quality problem”. Urban development, septic systems, and agricultural operations have been identified as the major sources of diffuse pollution in surface and ground water bodies. In recent decades, urban and agricultural Best Management Practices (BMP have been developed in several states to address agricultural water quality and water use impacts, including the reduction of nutrient loads to help meet water quality standards. Compliance with BMPs is associated with some costs to local governments, homeowners, and agricultural operations, but the improvements in water quality associated with BMP adoption are expected to yield significant benefits to society in the form of improved recreational opportunities, navigation, flood control, and ecosystem health. The development of sound policies and decision making processes require balancing the costs of BMP adoption to the agricultural operations with the social benefits to be derived from the improved water quality. In this paper we develop a benefits transfer model to provide estimates of the economic benefits of properly implemented and effective Best Management Practices (BMP throughout the state of Florida. These benefit estimates can be used in a cost-benefit framework to determine the optimal level of BMP adoption throughout the state of Florida and provide a framework for other regions to estimate the potential benefits of BMP-mediated water quality improvements.

  18. THE 31 DEG{sup 2} RELEASE OF THE STRIPE 82 X-RAY SURVEY: THE POINT SOURCE CATALOG

    Energy Technology Data Exchange (ETDEWEB)

    LaMassa, Stephanie M.; Urry, C. Megan; Ananna, Tonima; Civano, Francesca; Marchesi, Stefano; Pecoraro, Robert [Yale Center for Astronomy and Astrophysics, Physics Department, P.O. Box 208120, New Haven, CT 06520 (United States); Cappelluti, Nico; Comastri, Andrea; Brusa, Marcella [INAF-Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Böhringer, Hans; Chon, Gayoung [Max-Planck-Institut für extraterrestrische Physik, D-85748 Garching (Germany); Glikman, Eilat [Department of Physics, Middlebury College, Middlebury, VT 05753 (United States); Richards, Gordon [Department of Physics, Drexel University, 3141 Chestnut Street, Philadelphia, PA 19104 (United States); Cardamone, Carie [Department of Math and Science, Wheelock College, 200 Riverway, Boston, MA 02215 (United States); Farrah, Duncan [Department of Physics MC 0435, Virginia Polytechnic Institute and State University, 850 West Campus Drive, Blacksburg, VA 24061 (United States); Gilfanov, Marat [Max-Planck Institut für Astrophysik, Karl-Schwarzschild-Str. 1, Postfach 1317, D-85741 Garching (Germany); Green, Paul [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Komossa, S. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Lira, Paulina [Departamento de Astronomia, Universidad de Chile, Camino del Observatorio 1515, Santiago (Chile); Makler, Martin [Centro Brasileiro de Pesquisas Fisicas, Rua Dr Xavier Sigaud 150, Rio de Janeiro, RJ 22290-180 (Brazil); and others

    2016-02-01

    We release the next installment of the Stripe 82 X-ray survey point-source catalog, which currently covers 31.3 deg{sup 2} of the Sloan Digital Sky Survey (SDSS) Stripe 82 Legacy field. In total, 6181 unique X-ray sources are significantly detected with XMM-Newton (>5σ) and Chandra (>4.5σ). This catalog release includes data from XMM-Newton cycle AO 13, which approximately doubled the Stripe 82X survey area. The flux limits of the Stripe 82X survey are 8.7 × 10{sup −16} erg s{sup −1} cm{sup −2}, 4.7 × 10{sup −15} erg s{sup −1} cm{sup −2}, and 2.1 × 10{sup −15} erg s{sup −1} cm{sup −2} in the soft (0.5–2 keV), hard (2–10 keV), and full bands (0.5–10 keV), respectively, with approximate half-area survey flux limits of 5.4 × 10{sup −15} erg s{sup −1} cm{sup −2}, 2.9 × 10{sup −14} erg s{sup −1} cm{sup −2}, and 1.7 × 10{sup −14} erg s{sup −1} cm{sup −2}. We matched the X-ray source lists to available multi-wavelength catalogs, including updated matches to the previous release of the Stripe 82X survey; 88% of the sample is matched to a multi-wavelength counterpart. Due to the wide area of Stripe 82X and rich ancillary multi-wavelength data, including coadded SDSS photometry, mid-infrared WISE coverage, near-infrared coverage from UKIDSS and VISTA Hemisphere Survey, ultraviolet coverage from GALEX, radio coverage from FIRST, and far-infrared coverage from Herschel, as well as existing ∼30% optical spectroscopic completeness, we are beginning to uncover rare objects, such as obscured high-luminosity active galactic nuclei at high-redshift. The Stripe 82X point source catalog is a valuable data set for constraining how this population grows and evolves, as well as for studying how they interact with the galaxies in which they live.

  19. Genome Reduction in Psychromonas Species within the Gut of an Amphipod from the Ocean’s Deepest Point

    KAUST Repository

    Zhang, Weipeng

    2018-04-25

    Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth\\'s oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by Psychromonas, of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living Psychromonas strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine N-oxide (TMAO) reducing gene cluster in CDP1, suggesting that the

  20. Genome Reduction in Psychromonas Species within the Gut of an Amphipod from the Ocean’s Deepest Point

    KAUST Repository

    Zhang, Weipeng; Tian, Ren-Mao; Sun, Jin; Bougouffa, Salim; Ding, Wei; Cai, Lin; Lan, Yi; Tong, Haoya; Li, Yongxin; Jamieson, Alan J.; Bajic, Vladimir B.; Drazen, Jeffrey C.; Bartlett, Douglas; Qian, Pei-Yuan

    2018-01-01

    Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth's oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by Psychromonas, of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living Psychromonas strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine N-oxide (TMAO) reducing gene cluster in CDP1, suggesting that the

  1. Preliminary preview for a geographic and monitoring program project; a review of point source-nonpoint source effluent trading/offset systems in watersheds

    Science.gov (United States)

    Wood, Alexander Warren; Bernknopf, Richard L.

    2003-01-01

    Watershed-based trading and offset systems are being developed to improve policy-maker?s and regulator?s ability to assess nonpoint source impacts in watersheds and to evaluate the efficacy of using market-incentive programs for preserving environmental quality. An overview of the history of successful and failed trading programs throughout the United States suggests that certain political, economic, and scientific conditions within a temporal and spatial setting help meet water quality standards. The current lack of spontaneous trading among dischargers does not mean that a marketable permit trading system is an inherently inefficient regulatory approach. Rather, its infrequent use is the result of institutional and informational barriers. Improving and refining the earth science information and technologies may help determine whether trading is a suitable policy for improving water quality. However, it is debatable whether or not environmental information is the limiting factor. This paper reviews additional factors affecting the potential for instituting a trading policy. The motivation for investigating and reviewing the history of offsets and trading was inspired by a project in the preliminary stages being developed by U.S. Geological Survey Western Geographic Science Center and the Environmental Protection Agency Region IX. An offset feasibility study will be an integrated, map-based approach that incorporates environmental, economic, and statistical information to investigate the potential for using offsets to meet mercury Total Maximum Daily Loads in the Sacramento River watershed. A regional water-quality offset program is being studied that may help known point sources reduce mercury loading more cost effectively by the remediation of abandoned mines or other diffuse sources as opposed to more costly treatment at their own sites. An efficient offset program requires both a scientific basis and methods to translate that science into a regulatory decision

  2. Speckle noise reduction on a laser projection display via a broadband green light source.

    Science.gov (United States)

    Yu, Nan Ei; Choi, Ju Won; Kang, Heejong; Ko, Do-Kyeong; Fu, Shih-Hao; Liou, Jiun-Wei; Kung, Andy H; Choi, Hee Joo; Kim, Byoung Joo; Cha, Myoungsik; Peng, Lung-Han

    2014-02-10

    A broadband green light source was demonstrated using a tandem-poled lithium niobate (TPLN) crystal. The measured wavelength and temperature bandwidth were 6.5 nm and 100 °C, respectively, spectral bandwidth was 36 times broader than the periodically poled case. Although the conversion efficiency was smaller than in the periodic case, the TPLN device had a good figure of merit owing to the extremely large bandwidth for wavelength and temperature. The developed broadband green light source exhibited speckle noise approximately one-seventh of that in the conventional approach for a laser projection display.

  3. Dynamic analysis of ultrasonically levitated droplet with moving particle semi-implicit and distributed point source method

    Science.gov (United States)

    Wada, Yuji; Yuge, Kohei; Nakamura, Ryohei; Tanaka, Hiroki; Nakamura, Kentaro

    2015-07-01

    Numerical analysis of an ultrasonically levitated droplet with a free surface boundary is discussed. The droplet is known to change its shape from sphere to spheroid when it is suspended in a standing wave owing to the acoustic radiation force. However, few studies on numerical simulation have been reported in association with this phenomenon including fluid dynamics inside the droplet. In this paper, coupled analysis using the distributed point source method (DPSM) and the moving particle semi-implicit (MPS) method, both of which do not require grids or meshes to handle the moving boundary with ease, is suggested. A droplet levitated in a plane standing wave field between a piston-vibrating ultrasonic transducer and a reflector is simulated with the DPSM-MPS coupled method. The dynamic change in the spheroidal shape of the droplet is successfully reproduced numerically, and the gravitational center and the change in the spheroidal aspect ratio are discussed and compared with the previous literature.

  4. Radiation transport in earth for neutron and gamma ray point sources above an air-ground interface

    International Nuclear Information System (INIS)

    Lillie, R.A.; Santoro, R.T.

    1979-03-01

    Two-dimensional discrete ordinates methods were used to calculate the instantaneous dose rate in silicon and neutron and gamma ray fluences as a function of depth in earth from point sources at various heights (1.0, 61.3, and 731.5 meters) above an air--ground interface. The radiation incident on the earth's surface was transported through an earth-only and an earth--concrete model containing 0.9 meters of borated concrete beginning 0.5 meters below the earth's surface to obtain fluence distributions to a depth of 3.0 meters. The inclusion of borated concrete did not significantly reduce the total instantaneous dose rate in silicon and, in all cases, the secondary gamma ray fluence and corresponding dose are substantially larger than the primary neutron fluence and corresponding dose for depths greater than 0.6 meter. 4 figures, 4 tables

  5. Purification and reuse of non-point source wastewater via Myriophyllum-based integrative biotechnology: A review.

    Science.gov (United States)

    Liu, Feng; Zhang, Shunan; Luo, Pei; Zhuang, Xuliang; Chen, Xiang; Wu, Jinshui

    2018-01-01

    In this review, the applications of Myriophyllum-based integrative biotechnology to remove common non-point source (NPS) pollutants, such as nitrogen, phosphorus, heavy metals, and organic pollutants (e.g., pesticides and antibiotics) are summarized. The removal of these pollutants via various mechanisms, including uptake by plant and microbial communities in macrophyte-based treatment systems are discussed. This review highlights the potential use of Myriophyllum biomass to produce animal feed, fertilizer, and other valuable by-products, which can yield cost-effective returns and attract more attention to the regulation and recycling of NPS pollutants. In addition, it demonstrates that utilization of Myriophyllum species is a promising and reliable strategy for wastewater treatment. The future development of sustainable Myriophyllum-based treatment systems is discussed from various perspectives. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. From a water resource to a point pollution source: the daily journey of a coastal urban stream

    Directory of Open Access Journals (Sweden)

    LR. Rörig

    Full Text Available The aim of this study was to understand how a stream ecosystem that flows from its fountainhead to its mouth inside a city, changes from a water resource to a point pollution source. A multidisciplinary descriptive approach was adopted, including the short-term temporal and spatial determination of physical, chemical, biological and ecotoxicological variables. Results showed that water quality rapidly decreases with increasing urbanization, leading the system to acquire raw sewage attributes even in the first hundred meters after the fountainheads. Despite the tidal circulation near the stream mouth being restricted by shallowness, some improvement of the water quality was detected in this area. The multidisciplinary evaluation showed to be useful for obtaining a more realistic understanding of the stream degradation process, and to forecast restoration and mitigation measures.

  7. Determination of the specific resistance of individual freestanding ZnO nanowires with the low energy electron point source microscope

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Dirk Henning; Beyer, Andre; Voelkel, Berthold; Goelzhaeuser, Armin [Physik Supramolekularer Systeme, Universitaet Bielefeld (Germany); Schlenker, Eva; Bakin, Andrey; Waag, Andreas [Institut fuer Halbleitertechnik, Technische Universitaet Braunschweig (Germany)

    2008-07-01

    A low energy electron point source (LEEPS) microscope is used to determine the electrical conductivity of individual freestanding ZnO nanowires in UHV. The nanowires were contacted with a manipulation tip and I-V curves were taken at different wire lengths. From those, the specific resistance was calculated and separated from the contact resistance. By comparing the specific resistances of ZnO nanowires with diameters between 1100 and 48 nm, a large surface contribution for the thin nanowires was found. A geometric model for separation between surface and bulk contributions is given. The results of electrical transport measurements on vapor phase grown ZnO nanowires are discussed, as well as the size dependence of the wire resistance.

  8. Radiation transport in earth for neutron and gamma-ray point sources above an air-ground interface

    International Nuclear Information System (INIS)

    Lillie, R.A.; Santoro, R.T.

    1980-01-01

    Two-dimensional discrete-ordinates methods have been used to calculate the instantaneous dose rate in silicon and neutron and gamma-ray fluences as a function of depth in earth from point sources at various heights (1.0, 61.3, and 731.5 m) above an air-ground interface. The radiation incident on the earth's surface was transported through an earth-only and an earth-concrete model containing 0.9 m of borated concrete beginning 0.5 m below the earth's surface to obtain fluence distributions to a depth of 3.0 m. The inclusion of borated concrete did not significantly reduce the total instantaneous dose rate in silicon, and in all cases, the secondary gamma-ray fluence and corresponding dose are substantially larger than the primary neutron fluence and corresponding dose for depths > 0.6 m

  9. Agricultural non-point source pollution management in a reservoir watershed based on ecological network analysis of soil nitrogen cycling.

    Science.gov (United States)

    Xu, Wen; Cai, Yanpeng; Rong, Qiangqiang; Yang, Zhifeng; Li, Chunhui; Wang, Xuan

    2018-03-01

    The Miyun Reservoir plays a pivotal role in providing drinking water for the city of Beijing. In this research, ecological network analysis and scenario analysis were integrated to explore soil nitrogen cycling of chestnut and Chinese pine forests in the upper basin of the Miyun Reservoir, as well as to seek favorable fertilization modes to reduce agricultural non-point source pollution. Ecological network analysis results showed that (1) the turnover time was 0.04 to 0.37 year in the NH 4 + compartment and were 15.78 to 138.36 years in the organic N compartment; (2) the Finn cycling index and the ratio of indirect to direct flow were 0.73 and 11.92 for the chestnut forest model, respectively. Those of the Chinese pine forest model were 0.88 and 29.23, respectively; and (3) in the chestnut forest model, NO 3 - accounted for 96% of the total soil nitrogen loss, followed by plant N (2%), NH 4 + (1%), and organic N (1%). In the Chinese pine forest, NH 4 + accounted for 56% of the total soil nitrogen loss, followed by organic N (34%) and NO 3 - (10%). Fertilization mode was identified as the main factor affecting soil N export. To minimize NH 4 + and NO 3 - outputs while maintaining the current plant yield (i.e., 7.85e0 kg N/year), a fertilization mode of 162.50 kg N/year offered by manure should be adopted. Whereas, to achieve a maximum plant yield (i.e., 3.35e1 kg N/year) while reducing NH 4 + and NO 3 - outputs, a fertilization mode of 325.00 kg N/year offered by manure should be utilized. This research is of wide suitability to support agricultural non-point source pollution management at the watershed scale.

  10. Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

    Science.gov (United States)

    Woronowicz, Michael

    2017-01-01

    Providers of payloads carried aboard the International Space Station must conduct analyses to demonstrate that any planned gaseous venting events generate no more than a certain level of material that may interfere with optical measurements from other experiments or payloads located nearby. This requirement is expressed in terms of a maximum column number density (CND). Depending on the level of rarefaction, such venting may be characterized by effusion for low flow rates, or by a sonic distribution at higher levels. Since the relative locations of other sensitive payloads are often unknown because they may refer to future projects, this requirement becomes a search for the maximum CND along any path.In another application, certain astronomical observations make use of CND to estimate light attenuation from a distant star through gaseous plumes, such as the Fermi Bubbles emanating from the vicinity of the black hole at the center of our Milky Way galaxy, in order to infer the amount of material being expelled via those plumes.This paper presents analytical CND expressions developed for general straight paths based upon a free molecule point source model for steady effusive flow and for a distribution fitted to model flows from a sonic orifice. Among other things, in this Mach number range it is demonstrated that the maximum CND from a distant location occurs along the path parallel to the source plane that intersects the plume axis. For effusive flows this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plumes axis. For sonic plumes this ratio is reduced to about 43.

  11. Specific power reduction of an ion source due to heating and cathode sputtering of electrodes

    International Nuclear Information System (INIS)

    Hamilton, G.U.; Semashko, N.N.

    The potentialities and limitations of the water-cooled ion-optical system of the ion source designed for continuous operation of the high-power neutral beam injector are determined. The following problems are analyzed: thermal expansion and deformation of electrodes, electrode sputtering as a result of bombardment, and heat transfer to turbulent flow of water

  12. Cylindrical angular spectrum using Fourier coefficients of point light source and its application to fast hologram calculation.

    Science.gov (United States)

    Oh, Seungtaik; Jeong, Il Kwon

    2015-11-16

    We will introduce a new simple analytic formula of the Fourier coefficient of the 3D field distribution of a point light source to generate a cylindrical angular spectrum which captures the object wave in 360° in the 3D Fourier space. Conceptually, the cylindrical angular spectrum can be understood as a cylindrical version of the omnidirectional spectral approach of Sando et al. Our Fourier coefficient formula is based on an intuitive observation that a point light radiates uniformly in all directions. Our formula is defined over all frequency vectors lying on the entire sphere in the 3D Fourier space and is more natural and computationally more efficient for all around recording of the object wave than that of the previous omnidirectional spectral method. A generalized frequency-based occlusion culling method for an arbitrary complex object is also proposed to enhance the 3D quality of a hologram. As a practical application of the cylindrical angular spectrum, an interactive hologram example is presented together with implementation details.

  13. Assessment of the relationship between rural non-point source pollution and economic development in the Three Gorges Reservoir Area.

    Science.gov (United States)

    Zhang, Tong; Ni, Jiupai; Xie, Deti

    2016-04-01

    This study investigates the relationship between rural non-point source (NPS) pollution and economic development in the Three Gorges Reservoir Area (TGRA) by using the Environmental Kuznets Curve (EKC) hypothesis for the first time. Five types of pollution indicators, namely, fertilizer input density (FD), pesticide input density (PD), agricultural film input density (AD), grain residues impact (GI), and livestock manure impact (MI), were selected as rural NPS pollutant variables. Rural net income per capita was used as the indicator of economic development. Pollution load was generated by agricultural inputs (consumption of fertilizer, pesticide, and agricultural film) and economic growth with invert U-shaped features. The predicted turning points for FD, PD, and AD were at rural net income per capita levels of 6167.64, 6205.02, and 4955.29 CNY, respectively, which were all surpassed. However, the features between agricultural waste outputs (grain residues and livestock manure) and economic growth were inconsistent with the EKC hypothesis, which reflected the current trends of agricultural economic structure in the TGRA. Given that several other factors aside from economic development level could influence the pollutant generation in rural NPS, a further examination with long-run data support should be performed to understand the relationship between rural NPS pollution and income level.

  14. Calculation and analysis of the non-point source pollution in the upstream watershed of the Panjiakou Reservoir, People's Republic of China

    Science.gov (United States)

    Zhang, S.; Tang, L.

    2007-05-01

    Panjiakou Reservoir is an important drinking water resource in Haihe River Basin, Hebei Province, People's Republic of China. The upstream watershed area is about 35,000 square kilometers. Recently, the water pollution in the reservoir is becoming more serious owing to the non-point pollution as well as point source pollution on the upstream watershed. To effectively manage the reservoir and watershed and develop a plan to reduce pollutant loads, the loading of non-point and point pollution and their distribution on the upstream watershed must be understood fully. The SWAT model is used to simulate the production and transportation of the non-point source pollutants in the upstream watershed of the Panjiakou Reservoir. The loadings of non-point source pollutants are calculated for different hydrologic years and the spatial and temporal characteristics of non-point source pollution are studied. The stream network and topographic characteristics of the stream network and sub-basins are all derived from the DEM by ArcGIS software. The soil and land use data are reclassified and the soil physical properties database file is created for the model. The SWAT model was calibrated with observed data of several hydrologic monitoring stations in the study area. The results of the calibration show that the model performs fairly well. Then the calibrated model was used to calculate the loadings of non-point source pollutants for a wet year, a normal year and a dry year respectively. The time and space distribution of flow, sediment and non-point source pollution were analyzed depending on the simulated results. The comparison of different hydrologic years on calculation results is dramatic. The loading of non-point source pollution in the wet year is relatively larger but smaller in the dry year since the non-point source pollutants are mainly transported through the runoff. The pollution loading within a year is mainly produced in the flood season. Because SWAT is a

  15. DEVELOPMENT OF THE MODEL OF GALACTIC INTERSTELLAR EMISSION FOR STANDARD POINT-SOURCE ANALYSIS OF FERMI LARGE AREA TELESCOPE DATA

    Energy Technology Data Exchange (ETDEWEB)

    Acero, F.; Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Université Paris Diderot, Service d’Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Ackermann, M.; Buehler, R. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M. [Department of Physics and Astronomy, Clemson University, Kinard Lab of Physics, Clemson, SC 29634-0978 (United States); Albert, A.; Baldini, L.; Bloom, E. D.; Bottacini, E.; Caliandro, G. A.; Cameron, R. A. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bellazzini, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Bissaldi, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy); Bonino, R. [Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino (Italy); Brandt, T. J.; Buson, S. [NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Bregeon, J. [Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, Montpellier (France); Bruel, P., E-mail: isabelle.grenier@cea.fr, E-mail: casandjian@cea.fr [Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, Palaiseau (France); and others

    2016-04-01

    Most of the celestial γ rays detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope originate from the interstellar medium when energetic cosmic rays interact with interstellar nucleons and photons. Conventional point-source and extended-source studies rely on the modeling of this diffuse emission for accurate characterization. Here, we describe the development of the Galactic Interstellar Emission Model (GIEM), which is the standard adopted by the LAT Collaboration and is publicly available. This model is based on a linear combination of maps for interstellar gas column density in Galactocentric annuli and for the inverse-Compton emission produced in the Galaxy. In the GIEM, we also include large-scale structures like Loop I and the Fermi bubbles. The measured gas emissivity spectra confirm that the cosmic-ray proton density decreases with Galactocentric distance beyond 5 kpc from the Galactic Center. The measurements also suggest a softening of the proton spectrum with Galactocentric distance. We observe that the Fermi bubbles have boundaries with a shape similar to a catenary at latitudes below 20° and we observe an enhanced emission toward their base extending in the north and south Galactic directions and located within ∼4° of the Galactic Center.

  16. Locating single-point sources from arrival times containing large picking errors (LPEs): the virtual field optimization method (VFOM)

    Science.gov (United States)

    Li, Xi-Bing; Wang, Ze-Wei; Dong, Long-Jun

    2016-01-01

    Microseismic monitoring systems using local location techniques tend to be timely, automatic and stable. One basic requirement of these systems is the automatic picking of arrival times. However, arrival times generated by automated techniques always contain large picking errors (LPEs), which may make the location solution unreliable and cause the integrated system to be unstable. To overcome the LPE issue, we propose the virtual field optimization method (VFOM) for locating single-point sources. In contrast to existing approaches, the VFOM optimizes a continuous and virtually established objective function to search the space for the common intersection of the hyperboloids, which is determined by sensor pairs other than the least residual between the model-calculated and measured arrivals. The results of numerical examples and in-site blasts show that the VFOM can obtain more precise and stable solutions than traditional methods when the input data contain LPEs. Furthermore, we discuss the impact of LPEs on objective functions to determine the LPE-tolerant mechanism, velocity sensitivity and stopping criteria of the VFOM. The proposed method is also capable of locating acoustic sources using passive techniques such as passive sonar detection and acoustic emission.

  17. Neon dense plasma focus point x-ray source for ≤ 0.25 μm lithography

    International Nuclear Information System (INIS)

    Prasad, R.R.; Krishnan, M.; Berg, K.; Conlon, D.; Mangano, J.

    1994-01-01

    A discharge driven, dense plasma focus (DPF) in neon has been developed at SRL as a point x-ray source for sub-micron lithography. This source is presently capable of delivering ∼25 J/pulse of neon K-shell x-rays (8--14 angstrom) into 4 π steradians with a ∼1.4% wall plug efficiency at a 20 Hz repetition rate. The discharge is produced by a capacitor bank circuit (8 kV, 1.8 kJ) which has a fixed inductance of 11 nH and drives ∼ 320 kA currents into the DPF load, with ∼1 μs rise-times. X-rays are produced when a dense pinch of neon is formed along the axis of the DPF electrodes. The dense neon pinch has been found to be a cigar shaped object, ∼0.3 mm in diameter at the waist and ∼8 mm long on a singe shot. This source wanders slightly from shot to shot in an overall envelope which is ∼0.5--0.75 mm in diameter and ∼8 mm long. The spectrum of x-rays emitted by the pinch has been extensively studied. It has been found that 60% of the total x-ray output is radiated in the H-like and He-like lines centered at 12.9 angstrom and 40% of the output is radiated in the H-like and He-like continuum, centered at 9.8 angstrom. More than 4 x 10 5 discharges using a cooled DPF head have been fired producing x-rays. The variation in the measured x-ray output, over several hundreds of thousands of shots, corresponds to a variation in the dose delivered to a resist 40 cm from the source, of less than 1%. Data showing the measurement of the x-ray output, dose delivered to a resist, spectra of the source output, novel beam line concepts and potential lithographic applications will be presented

  18. Study of the interference of plumes released from two near-ground point sources in an open channel

    International Nuclear Information System (INIS)

    Oskouie, Shahin N.; Wang, Bing-Chen; Yee, Eugene

    2015-01-01

    Highlights: • DNS study of turbulent dispersion and mixing of passive scalars. • Interference of two passive plumes in a boundary layer flow. • Cross correlation, co-spectra and coherency spectra of two plumes. - Abstract: The dispersion and mixing of passive scalars released from two near-ground point sources into an open-channel flow are studied using direct numerical simulation. A comparative study based on eight test cases has been conducted to investigate the effects of Reynolds number and source separation distance on the dispersion and interference of the two plumes. In order to determine the nonlinear relationship between the variance of concentration fluctuations of the total plume and those produced by each of the two plumes, the covariance of the two concentration fields is studied in both physical and spectral spaces. The results show that at the source height, the streamwise evolution of the cross correlation between the fluctuating components of the two concentration fields can be classified into four stages, which feature zero, destructive and constructive interferences and a complete mixing state. The characteristics of these four stages of plume mixing are further confirmed through an analysis of the pre-multiplied co-spectra and coherency spectra. From the coherency spectrum, it is observed that there exists a range of ‘leading scales’, which are several times larger than the Kolmogorov scale but are smaller than or comparable to the scale of the most energetic eddies of turbulence. At the leading scales, the mixing between the two interfering plumes is the fastest and the coherency spectrum associated with these scales can quickly approach its asymptotic value of unity.

  19. Synthesis of AuPd alloyed nanoparticles via room-temperature electron reduction with argon glow discharge as electron source.

    Science.gov (United States)

    Yang, Manman; Wang, Zongyuan; Wang, Wei; Liu, Chang-Jun

    2014-01-01

    Argon glow discharge has been employed as a cheap, environmentally friendly, and convenient electron source for simultaneous reduction of HAuCl4 and PdCl2 on the anodic aluminum oxide (AAO) substrate. The thermal imaging confirms that the synthesis is operated at room temperature. The reduction is conducted with a short time (30 min) under the pressure of approximately 100 Pa. This room-temperature electron reduction operates in a dry way and requires neither hydrogen nor extra heating nor chemical reducing agent. The analyses using X-ray photoelectron spectroscopy (XPS) confirm all the metallic ions have been reduced. The characterization with X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) shows that AuPd alloyed nanoparticles are formed. There also exist some highly dispersed Au and Pd monometallic particles that cannot be detected by XRD and transmission electron microscopy (TEM) because of their small particle sizes. The observed AuPd alloyed nanoparticles are spherical with an average size of 14 nm. No core-shell structure can be observed. The room-temperature electron reduction can be operated in a larger scale. It is an easy way for the synthesis of AuPd alloyed nanoparticles.

  20. Probing the Spatial Distribution of the Interstellar Dust Medium by High Angular Resolution X-ray Halos of Point Sources

    Science.gov (United States)

    Xiang, Jingen

    X-rays are absorbed and scattered by dust grains when they travel through the interstellar medium. The scattering within small angles results in an X-ray ``halo''. The halo properties are significantly affected by the energy of radiation, the optical depth of the scattering, the grain size distributions and compositions, and the spatial distribution of dust along the line of sight (LOS). Therefore analyzing the X-ray halo properties is an important tool to study the size distribution and spatial distribution of interstellar grains, which plays a central role in the astrophysical study of the interstellar medium, such as the thermodynamics and chemistry of the gas and the dynamics of star formation. With excellent angular resolution, good energy resolution and broad energy band, the Chandra ACIS is so far the best instrument for studying the X-ray halos. But the direct images of bright sources obtained with ACIS usually suffer from severe pileup which prevents us from obtaining the halos in small angles. We first improve the method proposed by Yao et al to resolve the X-ray dust scattering halos of point sources from the zeroth order data in CC-mode or the first order data in TE mode with Chandra HETG/ACIS. Using this method we re-analyze the Cygnus X-1 data observed with Chandra. Then we studied the X-ray dust scattering halos around 17 bright X-ray point sources using Chandra data. All sources were observed with the HETG/ACIS in CC-mode or TE-mode. Using the interstellar grain models of WD01 model and MRN model to fit the halo profiles, we get the hydrogen column densities and the spatial distributions of the scattering dust grains along the line of sights (LOS) to these sources. We find there is a good linear correlation not only between the scattering hydrogen column density from WD01 model and the one from MRN model, but also between N_{H} derived from spectral fits and the one derived from the grain models WD01 and MRN (except for GX 301-2 and Vela X-1): N

  1. Contaminant Flux Reduction Barriers for Managing Difficult-to-Treat Source Zones in Unconsolidated Media

    Science.gov (United States)

    2017-06-20

    estimated viscosity of 3-4 cP.  Solutions-IES Novel Silica Gel/Veg-Oil Grout: 5 wt- % of emulsified vegetable oil (EVO), 10 wt-% of sodium...site must have a lower low permeability unit such as a clay to prevent up flow; and a four sided barrier is recommended (three sided barriers are...depth to groundwater (ង ft)  Transmissive zone preferably with an underlying clay layer  Good accessibility to source zone  Availability of

  2. Stator Current Harmonic Reduction in a Novel Half Quasi-Z-Source Wind Power Generation System

    Directory of Open Access Journals (Sweden)

    Shoudao Huang

    2016-09-01

    Full Text Available The generator stator current gets distorted with unacceptable levels of total harmonic distortion (THD because impedance-source wind power generation systems use three-phase diode rectifiers. The stator current harmonics will cause increasing losses and torque ripple, which reduce the efficiency and stability of the system. This paper proposes a novel half quasi-Z-source inverter (H-qZSI for grid-connected wind power generation systems, which can reduce the generator stator current harmonics a great deal. When H-qZSI operates in the shoot-through zero state, the derivative of the generator stator current is only determined by the instantaneous value of the generator stator voltage, so the nonlinear relationship between generator stator current and stator voltage is improved compared with the traditional impedance-source inverter. Theoretically, it is indicated that the stator current harmonics can be reduced effectively by means of the proposed H-qZSI. Finally, simulation and experimental results are given to verify the theoretical analysis.

  3. Genome Reduction in Psychromonas Species within the Gut of an Amphipod from the Ocean’s Deepest Point

    Science.gov (United States)

    Zhang, Weipeng; Tian, Ren-Mao; Sun, Jin; Bougouffa, Salim; Ding, Wei; Cai, Lin; Lan, Yi; Tong, Haoya; Li, Yongxin; Jamieson, Alan J.; Bajic, Vladimir B.; Drazen, Jeffrey C.; Bartlett, Douglas

    2018-01-01

    ABSTRACT Amphipods are the dominant scavenging metazoan species in the Mariana Trench, the deepest known point in Earth’s oceans. Here the gut microbiota of the amphipod Hirondellea gigas collected from the Challenger and Sirena Deeps of the Mariana Trench were investigated. The 11 amphipod individuals included for analyses were dominated by Psychromonas, of which a nearly complete genome was successfully recovered (designated CDP1). Compared with previously reported free-living Psychromonas strains, CDP1 has a highly reduced genome. Genome alignment showed deletion of the trimethylamine N-oxide (TMAO) reducing gene cluster in CDP1, suggesting that the “piezolyte” function of TMAO is more important than its function in respiration, which may lead to TMAO accumulation. In terms of nutrient utilization, the bacterium retains its central carbohydrate metabolism but lacks most of the extended carbohydrate utilization pathways, suggesting the confinement of Psychromonas to the host gut and sequestration from more variable environmental conditions. Moreover, CDP1 contains a complete formate hydrogenlyase complex, which might be involved in energy production. The genomic analyses imply that CDP1 may have developed adaptive strategies for a lifestyle within the gut of the hadal amphipod H. gigas. IMPORTANCE As a unique but poorly investigated habitat within marine ecosystems, hadal trenches have received interest in recent years. This study explores the gut microbial composition and function in hadal amphipods, which are among the dominant carrion feeders in hadal habitats. Further analyses of a dominant strain revealed genomic features that may contribute to its adaptation to the amphipod gut environment. Our findings provide new insights into animal-associated bacteria in the hadal biosphere. PMID:29657971

  4. Quad Cities Unit 2 Main Steam Line Acoustic Source Identification and Load Reduction

    International Nuclear Information System (INIS)

    DeBoo, Guy; Ramsden, Kevin; Gesior, Roman

    2006-01-01

    The Quad Cities Units 1 and 2 have a history of steam line vibration issues. The implementation of an Extended Power Up-rate resulted in significant increases in steam line vibration as well as acoustic loading of the steam dryers, which led to equipment failures and fatigue cracking of the dryers. This paper discusses the results of extensive data collection on the Quad Cities Unit 2 replacement dryer and the Main Steam Lines. This data was taken with the intent of identifying acoustic sources in the steam system. Review of the data confirmed that vortex shedding coupled column resonance in the relief and safety valve stub pipes were the principal sources of large magnitude acoustic loads in the main steam system. Modifications were developed in sub-scale testing to alter the acoustic properties of the valve standpipes and add acoustic damping to the system. The modifications developed and installed consisted of acoustic side branches that were attached to the Electromatic Relief Valve (ERV) and Main Steam Safety Valve (MSSV) attachment pipes. Subsequent post-modification testing was performed in plant to confirm the effectiveness of the modifications. The modifications have been demonstrated to reduce vibration loads at full Extended Power Up-rate (EPU) conditions to levels below those at Original Licensed Thermal Power (OLTP). (authors)

  5. A paddy eco-ditch and wetland system to reduce non-point source pollution from rice-based production system while maintaining water use efficiency.

    Science.gov (United States)

    Xiong, Yujiang; Peng, Shizhang; Luo, Yufeng; Xu, Junzeng; Yang, Shihong

    2015-03-01

    Non-point source (NPS) pollution from agricultural drainage has aroused widespread concerns throughout the world due to its contribution to eutrophication of water bodies. To remove nitrogen (N) and phosphorus (P) from agricultural drainage in situ, a Paddy Eco-ditch and Wetland System (PEDWS) was designed and built based on the characteristics of the irrigated rice district. A 2-year (2012-2013) field experiment was conducted to evaluate the performance of this system in Gaoyou Irrigation District in Eastern China. The results showed that the reduction in water input in paddy field of the PEDWS enabled the maintenance of high rice yield; it significantly increased irrigation water productivity (WPI), gross water productivity (WPG), and evapotranspiration water productivity (WPET) by 109.2, 67.1, and 17.6%, respectively. The PEDWS dramatically decreased N and P losses from paddy field. Compared with conventional irrigation and drainage system (CIDS), the amount of drainage water from PEDWS was significantly reduced by 56.2%, the total nitrogen (TN) concentration in drainage was reduced by 42.6%, and thus the TN and total phosphorus (TP) losses were reduced by 87.8 and 70.4%. PEDWS is technologically feasible and applicable to treat nutrient losses from paddy fields in situ and can be used in similar areas.

  6. A Point Source of a Different Color: Identifying a Gap in United States Regulatory Policy for “Green” CSO Treatment Using Constructed Wetlands

    Directory of Open Access Journals (Sweden)

    Zeno F. Levy

    2014-04-01

    Full Text Available Up to 850 billion gallons of untreated combined sewer overflow (CSO is discharged into waters of the United States each year. Recent changes in CSO management policy support green infrastructure (GI technologies as “front of the pipe” approaches to discharge mitigation by detention/reduction of urban stormwater runoff. Constructed wetlands for CSO treatment have been considered among suites of GI solutions. However, these wetlands differ fundamentally from other GI technologies in that they are “end of the pipe” treatment systems that discharge from a point source, and are therefore regulated in the U.S. under the National Pollution Discharge Elimination System (NPDES. We use a comparative regulatory analysis to examine the U.S. policy framework for CSO treatment wetlands. We find in all cases that permitting authorities have used best professional judgment to determine effluent limits and compliance monitoring requirements, referencing technology and water quality-based standards originally developed for traditional “grey” treatment systems. A qualitative comparison with Europe shows less stringent regulatory requirements, perhaps due to institutionalized design parameters. We recommend that permitting authorities develop technical guidance documents for evaluation of “green” CSO treatment systems that account for their unique operational concerns and benefits with respect to sustainable development.

  7. Impact of changes in labor resources and transfers of land use rights on agricultural non-point source pollution in Jiangsu Province, China.

    Science.gov (United States)

    Lu, Hua; Xie, Hualin

    2018-02-01

    This study systematically explores the likely mechanisms driving the effect of the transfer of agricultural land use rights (ALURs) on agricultural non-point source pollution (ANSP) in the context of changing agricultural labor resources. It quantitatively estimates the direction and degree of this influence from a microeconomic perspective using data from rural households. The results reveal that economies of scale caused by ALURs transfers contribute to reducing both the ANSP and marginal costs of inputs. Changes in agricultural labor resources lead to reductions in agricultural labor supply and negatively impact on ANSP. Encouraging farmers to participate in ALURs transfers, therefore, helps to reduce ANSP. The government and related departments should implement policies that support farmers who decide to rent an entire village's land or the adjacent land to achieve economies of scale. Accelerating the development of small farm machinery that is suitable for smaller farm plots and the elderly can serve to reduce the use of chemical fertilizer and promote green production and sustainable agricultural development. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Synoptic monitoring as an approach to discriminating between point and diffuse source contributions to zinc loads in mining impacted catchments.

    Science.gov (United States)

    Banks, V J; Palumbo-Roe, B

    2010-09-01

    One of the global legacies of industrialisation is the environmental impacts of historic mineral exploitation. Recent national initiatives to manage the impacts on ground and surface waters have driven the need to develop better techniques for assessing understanding of the catchment-scale distribution and characterisation of the relative contribution of point and diffuse contaminant sources. The benefits of a detailed, multidisciplinary investigation are highlighted through a case study focused on the Rookhope Burn, a tributary of the River Wear, which falls within a significantly mine impacted area of the North Pennines Orefield, UK. Zinc (Zn) has been identified as the contaminant of concern within this catchment, which is judged by the Environment Agency to be at risk of failing to achieve good water quality status in the context of the Water Framework Directive. The results of synoptic flow monitoring and sampling for chemical determinations of major and trace elements have been used to calculate mass balances of instream and inflow chemical loads in the Rookhope Burn. Despite a dominant impact on the water quality from a mine outburst (especially Zn [1.45 to 2.42 mg/l], Fe [2.18 to 3.97 mg/l], Mn [3.69 to 6.77 mg/l], F [3.99 to 4.80 mg/l] and SO(4) [178 to 299 mg/l]), mass balance calculations combined with geological mapping have facilitated the identification of significant, previously unknown, subsurface contributions of Zn contaminated groundwater (with Zn concentrations in excess of 0.4 to 0.9 mg/l and 0.18 to 0.36 mg/l) to the Burn. The subsurface contributions exhibit spatial correspondence to mine workings with associated mineral veins and adits, or to points of suspected karst groundwater resurgence. These findings reiterate the challenges posed in decision making with respect to remediation, in this case in the context of the management of significant subsurface contributions.

  9. From Particles and Point Clouds to Voxel Models: High Resolution Modeling of Dynamic Landscapes in Open Source GIS

    Science.gov (United States)

    Mitasova, H.; Hardin, E. J.; Kratochvilova, A.; Landa, M.

    2012-12-01

    Multitemporal data acquired by modern mapping technologies provide unique insights into processes driving land surface dynamics. These high resolution data also offer an opportunity to improve the theoretical foundations and accuracy of process-based simulations of evolving landforms. We discuss development of new generation of visualization and analytics tools for GRASS GIS designed for 3D multitemporal data from repeated lidar surveys and from landscape process simulations. We focus on data and simulation methods that are based on point sampling of continuous fields and lead to representation of evolving surfaces as series of raster map layers or voxel models. For multitemporal lidar data we present workflows that combine open source point cloud processing tools with GRASS GIS and custom python scripts to model and analyze dynamics of coastal topography (Figure 1) and we outline development of coastal analysis toolbox. The simulations focus on particle sampling method for solving continuity equations and its application for geospatial modeling of landscape processes. In addition to water and sediment transport models, already implemented in GIS, the new capabilities under development combine OpenFOAM for wind shear stress simulation with a new module for aeolian sand transport and dune evolution simulations. Comparison of observed dynamics with the results of simulations is supported by a new, integrated 2D and 3D visualization interface that provides highly interactive and intuitive access to the redesigned and enhanced visualization tools. Several case studies will be used to illustrate the presented methods and tools and demonstrate the power of workflows built with FOSS and highlight their interoperability.Figure 1. Isosurfaces representing evolution of shoreline and a z=4.5m contour between the years 1997-2011at Cape Hatteras, NC extracted from a voxel model derived from series of lidar-based DEMs.

  10. Stratospheric ozone reduction and its relation to natural and man made sources

    Energy Technology Data Exchange (ETDEWEB)

    Isaksen, I S [Oslo Univ. (Norway). Dept. of Geophysics

    1996-12-31

    Approximately 90 % of the total ozone mass is in the stratosphere (between approximately 12 and 50 km), the rest is in the troposphere (below 12 km). The global distribution of ozone in the stratosphere and its variation over time have been studied extensively over several decades. These studies include observations by ground based instruments (e.g. Dobson instruments), instruments on airborne platforms (e.g. ozone sondes) and on satellites, and model studies which simulate the chemical and dynamical behaviour of the stratosphere. These studies have given good information about the processes which determine the ozone distribution, and how man made emissions affect the distribution. Observations have revealed that there are large year to year variations in stratospheric ozone above a particular location. These variations are difficult to predict as they are connected to irregular weather patterns. However, the observations have shown that there has been a long term decrease in stratospheric ozone on a global scale during the last two decades. The decrease has been most pronounced during the last five to six years and is seen both in the Northern and the Southern Hemispheres. The strong decrease in stratospheric ozone over the Antarctic continent, which has been observed since the mid 80s, and which has reduced the total ozone column with more than 50 % compared with earlier observations, is proven to be a result of increased man made emissions of CFCs. There are also mounting evidences that Northern Hemispheric ozone reductions observed since 1980 are connected to man made emissions of CFCs

  11. Stratospheric ozone reduction and its relation to natural and man made sources

    Energy Technology Data Exchange (ETDEWEB)

    Isaksen, I.S. [Oslo Univ. (Norway). Dept. of Geophysics

    1995-12-31

    Approximately 90 % of the total ozone mass is in the stratosphere (between approximately 12 and 50 km), the rest is in the troposphere (below 12 km). The global distribution of ozone in the stratosphere and its variation over time have been studied extensively over several decades. These studies include observations by ground based instruments (e.g. Dobson instruments), instruments on airborne platforms (e.g. ozone sondes) and on satellites, and model studies which simulate the chemical and dynamical behaviour of the stratosphere. These studies have given good information about the processes which determine the ozone distribution, and how man made emissions affect the distribution. Observations have revealed that there are large year to year variations in stratospheric ozone above a particular location. These variations are difficult to predict as they are connected to irregular weather patterns. However, the observations have shown that there has been a long term decrease in stratospheric ozone on a global scale during the last two decades. The decrease has been most pronounced during the last five to six years and is seen both in the Northern and the Southern Hemispheres. The strong decrease in stratospheric ozone over the Antarctic continent, which has been observed since the mid 80s, and which has reduced the total ozone column with more than 50 % compared with earlier observations, is proven to be a result of increased man made emissions of CFCs. There are also mounting evidences that Northern Hemispheric ozone reductions observed since 1980 are connected to man made emissions of CFCs

  12. Sources, potentials and fields in Lorenz and Coulomb gauge: Cancellation of instantaneous interactions for moving point charges

    International Nuclear Information System (INIS)

    Wundt, B.J.; Jentschura, U.D.

    2012-01-01

    We investigate the coupling of the electromagnetic sources (charge and current densities) to the scalar and vector potentials in classical electrodynamics, using Green function techniques. As is well known, the scalar potential shows an action-at-a-distance behavior in Coulomb gauge. The conundrum generated by the instantaneous interaction has intrigued physicists for a long time. Starting from the differential equations that couple the sources to the potentials, we here show in a concise derivation, using the retarded Green function, how the instantaneous interaction cancels in the calculation of the electric field. The time derivative of a specific additional term in the vector potential, present only in Coulomb gauge, yields a supplementary contribution to the electric field which cancels the gradient of the instantaneous Coulomb gauge scalar potential, as required by gauge invariance. This completely eliminates the contribution of the instantaneous interaction from the electric field. It turns out that a careful formulation of the retarded Green function, inspired by field theory, is required in order to correctly treat boundary terms in partial integrations. Finally, compact integral representations are derived for the Liénard–Wiechert potentials (scalar and vector) in Coulomb gauge which manifestly contain two compensating action-at-a-distance terms. - Highlights: ► We investigate action-at-a-distance effects in electrodynamics in detail. ► We calculate the instantaneous interactions for scalar and vector potentials. ► The cancellation mechanism involves the retarded Green function. ► The mechanism is confirmed on the example of moving point charges. ► The Green function has to be treated with care for nontrivial boundary terms.

  13. Morphology, chemistry and distribution of neoformed spherulites in agricultural land affected by metallurgical point-source pollution

    Energy Technology Data Exchange (ETDEWEB)

    Leguedois, Sophie; Oort, Folkert van; Jongmans, Toine; Chevallier, Pierre

    2004-07-01

    Metal distribution patterns in superficial soil horizons of agricultural land affected by metallurgical point-source pollution were studied using optical and electron microscopy, synchrotron radiation and spectroscopy analyses. The site is located in northern France, at the center of a former entry lane to a bunker of World War II, temporarily paved with coarse industrial waste fragments and removed at the end of the war. Thin sections made from undisturbed soil samples from A and B horizons were studied. Optical microscopy revealed the occurrence of yellow micrometer-sized (Ap horizon) and red decamicrometer-sized spherulites (AB, B{sub 1}g horizons) as well as distinct distribution patterns. The chemical composition of the spherulites was dominated by Fe, Mn, Zn, Pb, Ca, and P. Comparison of calculated Zn stocks, both in the groundmass and in spherulites, showed a quasi-exclusive Zn accumulation in these neoformed features. Their formation was related to several factors: (i) liberation of metal elements due to weathering of waste products, (ii) Ca and P supply from fertilizing practices, (iii) co-precipitation of metal elements and Ca and P in a porous soil environment, after slow exudation of a supersaturated soil solution in more confined mineral media. - Metal spherulites may act as high metal-trapping mineral phases in polluted agricultural soils.

  14. Modeling Multi-Event Non-Point Source Pollution in a Data-Scarce Catchment Using ANN and Entropy Analysis

    Directory of Open Access Journals (Sweden)

    Lei Chen

    2017-06-01

    Full Text Available Event-based runoff–pollutant relationships have been the key for water quality management, but the scarcity of measured data results in poor model performance, especially for multiple rainfall events. In this study, a new framework was proposed for event-based non-point source (NPS prediction and evaluation. The artificial neural network (ANN was used to extend the runoff–pollutant relationship from complete data events to other data-scarce events. The interpolation method was then used to solve the problem of tail deviation in the simulated pollutographs. In addition, the entropy method was utilized to train the ANN for comprehensive evaluations. A case study was performed in the Three Gorges Reservoir Region, China. Results showed that the ANN performed well in the NPS simulation, especially for light rainfall events, and the phosphorus predictions were always more accurate than the nitrogen predictions under scarce data conditions. In addition, peak pollutant data scarcity had a significant impact on the model performance. Furthermore, these traditional indicators would lead to certain information loss during the model evaluation, but the entropy weighting method could provide a more accurate model evaluation. These results would be valuable for monitoring schemes and the quantitation of event-based NPS pollution, especially in data-poor catchments.

  15. An accurate discontinuous Galerkin method for solving point-source Eikonal equation in 2-D heterogeneous anisotropic media

    Science.gov (United States)

    Le Bouteiller, P.; Benjemaa, M.; Métivier, L.; Virieux, J.

    2018-03-01

    Accurate numerical computation of wave traveltimes in heterogeneous media is of major interest for a large range of applications in seismics, such as phase identification, data windowing, traveltime tomography and seismic imaging. A high level of precision is needed for traveltimes and their derivatives in applications which require quantities such as amplitude or take-off angle. Even more challenging is the anisotropic case, where the general Eikonal equation is a quartic in the derivatives of traveltimes. Despite their efficiency on Cartesian meshes, finite-difference solvers are inappropriate when dealing with unstructured meshes and irregular topographies. Moreover, reaching high orders of accuracy generally requires wide stencils and high additional computational load. To go beyond these limitations, we propose a discontinuous-finite-element-based strategy which has the following advantages: (1) the Hamiltonian formalism is general enough for handling the full anisotropic Eikonal equations; (2) the scheme is suitable for any desired high-order formulation or mixing of orders (p-adaptivity); (3) the solver is explicit whatever Hamiltonian is used (no need to find the roots of the quartic); (4) the use of unstructured meshes provides the flexibility for handling complex boundary geometries such as topographies (h-adaptivity) and radiation boundary conditions for mimicking an infinite medium. The point-source factorization principles are extended to this discontinuous Galerkin formulation. Extensive tests in smooth analytical media demonstrate the high accuracy of the method. Simulations in strongly heterogeneous media illustrate the solver robustness to realistic Earth-sciences-oriented applications.

  16. Point Source contamination approach for hydrological risk assessment of a major hypothetical accident from second research reactor at Inshas site

    International Nuclear Information System (INIS)

    Sadek, M.A.; Tawfik, F.S.

    2002-01-01

    The point source contamination mechanism and the deterministic conservative approach have been implemented to demonstrate the hazards of hydrological pollution due to a major hypothetical accident in the second research reactor at Inshas. The radioactive inventory is assumed to be dissolved in 75% of the cooling water (25% are lost) and comes directly into contact with ground water and moved down gradient. Five radioisotopes(I-129, Sr-90, Ru-106, Cs-134 and Cs-137) of the entire inventory are found to be highly durable and represent vulnerability in the environment. Their downstream spread indices; C max : maximum concentration at the focus of the moving ellipse, delta: pollution duration at different distances, A:polluted area at different distances and X min : safety distance from the reactor, were calculated based on analytical solutions of the convection-dispersion partial differential equation for absorbable and decaying species. The largest downstream contamination range was found for Sr-90 and Ru-106 but still no potential. The geochemical and hydrological parameters of the water bearing formations play a great role in buffering and limiting the radiation effects. These reduce the retention time of the radioisotopes several order of magnitudes in the polluted distances. Sensitivity analysis of the computed pollution ranges shows low sensitivity to possible potential for variations activity of nuclide inventory, dispersivity and saturated thickness and high sensitivity for possible variations in groundwater velocity and retention factors

  17. Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems.

    Science.gov (United States)

    Munier, B; Bendell, L I

    2018-01-01

    Nine urban intertidal regions in Burrard Inlet, Vancouver, British Columbia, Canada, were sampled for plastic debris. Debris included macro and micro plastics and originated from a wide diversity of uses ranging from personal hygiene to solar cells. Debris was characterized for its polymer through standard physiochemical characteristics, then subject to a weak acid extraction to remove the metals, zinc, copper, cadmium and lead from the polymer. Recently manufactured low density polyethylene (LDPE), nylon, polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS) and polyvinyl chloride (PVC) were subject to the same extraction. Data was statistically analyzed by appropriate parametric and non-parametric tests when needed with significance set at P Plastic debris will affect metals within coastal ecosystems by; 1) providing a sorption site (copper and lead), notably for PVC 2) desorption from the plastic i.e., the "inherent" load (cadmium and zinc) and 3) serving as a point source of acute trace metal exposure to coastal ecosystems. All three mechanisms will put coastal ecosystems at risk to the toxic effects of these metals.

  18. The validation of organ dose calculations using voxel phantoms and Monte Carlo methods applied to point and water immersion sources.

    Science.gov (United States)

    Hunt, J G; da Silva, F C A; Mauricio, C L P; dos Santos, D S

    2004-01-01

    The Monte Carlo program 'Visual Monte Carlo-dose calculation' (VMC-dc) uses a voxel phantom to simulate the body organs and tissues, transports photons through this phantom and reports the absorbed dose received by each organ and tissue relevant to the calculation of effective dose as defined in ICRP Publication 60. This paper shows the validation of VMC-dc by comparison with EGSnrc and with a physical phantom containing TLDs. The validation of VMC-dc by comparison with EGSnrc was made for a collimated beam of 0.662 MeV photons irradiating a cube of water. For the validation by comparison with the physical phantom, the case considered was a whole body irradiation with a point 137Cs source placed at a distance of 1 m from the thorax of an Alderson-RANDO phantom. The validation results show good agreement for the doses obtained using VMC-dc and EGSnrc calculations, and from VMC-dc and TLD measurements. The program VMC-dc was then applied to the calculation of doses due to immersion in water containing gamma emitters. The dose conversion coefficients for water immersion are compared with their equivalents in the literature.

  19. The validation of organ dose calculations using voxel phantoms and Monte Carlo methods applied to point and water immersion sources

    International Nuclear Information System (INIS)

    Hunt, J. G.; Da Silva, F. C. A.; Mauricio, C. L. P.; Dos Santos, D. S.

    2004-01-01

    The Monte Carlo program 'Visual Monte Carlo-dose calculation' (VMC-dc) uses a voxel phantom to simulate the body organs and tissues, transports photons through this phantom and reports the absorbed dose received by each organ and tissue relevant to the calculation of effective dose as defined in ICRP Publication 60. This paper shows the validation of VMC-dc by comparison with EGSnrc and with a physical phantom containing TLDs. The validation of VMC-dc by comparison with EGSnrc was made for a collimated beam of 0.662 MeV photons irradiating a cube of water. For the validation by comparison with the physical phantom, the case considered was a whole body irradiation with a point 137 Cs source placed at a distance of 1 m from the thorax of an Alderson-RANDO phantom. The validation results show good agreement for the doses obtained using VMC-dc and EGSnrc calculations, and from VMC-dc and TLD measurements. The program VMC-dc was then applied to the calculation of doses due to immersion in water containing gamma emitters. The dose conversion coefficients for water immersion are compared with their equivalents in the literature. (authors)

  20. Observation of Point-Light-Walker Locomotion Induces Motor Resonance When Explicitly Represented; An EEG Source Analysis Study

    Directory of Open Access Journals (Sweden)

    Alberto Inuggi

    2018-03-01

    Full Text Available Understanding human motion, to infer the goal of others' actions, is thought to involve the observer's motor repertoire. One prominent class of actions, the human locomotion, has been object of several studies, all focused on manipulating the shape of degraded human figures like point-light walker (PLW stimuli, represented as walking on the spot. Nevertheless, since the main goal of the locomotor function is to displace the whole body from one position to the other, these stimuli might not fully represent a goal-directed action and thus might not be able to induce the same motor resonance mechanism expected when observing a natural locomotion. To explore this hypothesis, we recorded the event-related potentials (ERP of canonical/scrambled and translating/centered PLWs decoding. We individuated a novel ERP component (N2c over central electrodes, around 435 ms after stimulus onset, for translating compared to centered PLW, only when the canonical shape was preserved. Consistently with our hypothesis, sources analysis associated this component to the activation of trunk and lower legs primary sensory-motor and supplementary motor areas. These results confirm the role of own motor repertoire in processing human action and suggest that ERP can detect the associated motor resonance only when the human figure is explicitly involved in performing a meaningful action.

  1. The (2+1)-dimensional axial universes—solutions to the Einstein equations, dimensional reduction points and Klein–Fock–Gordon waves

    International Nuclear Information System (INIS)

    Fiziev, P P; Shirkov, D V

    2012-01-01

    The paper presents a generalization and further development of our recent publications, where solutions of the Klein–Fock–Gordon equation defined on a few particular D = (2 + 1)-dimensional static spacetime manifolds were considered. The latter involve toy models of two-dimensional spaces with axial symmetry, including dimensional reduction to the one-dimensional space as a singular limiting case. Here, the non-static models of space geometry with axial symmetry are under consideration. To make these models closer to physical reality, we define a set of ‘admissible’ shape functions ρ(t, z) as the (2 + 1)-dimensional Einstein equation solutions in the vacuum spacetime, in the presence of the Λ-term and for the spacetime filled with the standard ‘dust’. It is curious that in the last case the Einstein equations reduce to the well-known Monge–Ampère equation, thus enabling one to obtain the general solution of the Cauchy problem, as well as a set of other specific solutions involving one arbitrary function. A few explicit solutions of the Klein–Fock–Gordon equation in this set are given. An interesting qualitative feature of these solutions relates to the dimensional reduction points, their classification and time behavior. In particular, these new entities could provide us with novel insight into the nature of P- and T-violations and of the Big Bang. A short comparison with other attempts to utilize the dimensional reduction of the spacetime is given. (paper)

  2. X-Ray and Near-Infrared Spectroscopy of Dim X-Ray Point Sources Constituting the Galactic Ridge X-Ray Emission

    Directory of Open Access Journals (Sweden)

    Kumiko Morihana

    2014-12-01

    Full Text Available We present the results of X-ray and Near-Infrared observations of the Galactic Ridge X-ray Emission (GRXE. We extracted 2,002 X-ray point sources in the Chandra Bulge Field (l =0°.113, b = 1°.424 down to ~10-14.8 ergscm-2s-1 in 2-8 keV band with the longest observation (900 ks of the GRXE. Based on X-ray brightness and hardness, we classied the X-ray point sources into three groups: A (hard, B (soft and broad spectrum, and C (soft and peaked spectrum. In order to know populations of the X-ray point sources, we carried out NIR imaging and spectroscopy observation. We identied 11% of X-ray point sources with NIR and extracted NIR spectra for some of them. Based on X-ray and NIR properties, we concluded that non-thermal sources in the group A are mostly active galactic nuclei and the thermal sources are mostly white dwarf binaries such as cataclysmic variables (CVs and Pre-CVs. We concluded that the group B and C sources are X-ray active stars in flare and quiescence, respectively.

  3. A Comparative Analysis of Vibrio cholerae Contamination in Point-of-Drinking and Source Water in a Low-Income Urban Community, Bangladesh.

    Science.gov (United States)

    Ferdous, Jannatul; Sultana, Rebeca; Rashid, Ridwan B; Tasnimuzzaman, Md; Nordland, Andreas; Begum, Anowara; Jensen, Peter K M

    2018-01-01

    Bangladesh is a cholera endemic country with a population at high risk of cholera. Toxigenic and non-toxigenic Vibrio cholerae ( V. cholerae ) can cause cholera and cholera-like diarrheal illness and outbreaks. Drinking water is one of the primary routes of cholera transmission in Bangladesh. The aim of this study was to conduct a comparative assessment of the presence of V. cholerae between point-of-drinking water and source water, and to investigate the variability of virulence profile using molecular methods of a densely populated low-income settlement of Dhaka, Bangladesh. Water samples were collected and tested for V. cholerae from "point-of-drinking" and "source" in 477 study households in routine visits at 6 week intervals over a period of 14 months. We studied the virulence profiles of V. cholerae positive water samples using 22 different virulence gene markers present in toxigenic O1/O139 and non-O1/O139 V. cholerae using polymerase chain reaction (PCR). A total of 1,463 water samples were collected, with 1,082 samples from point-of-drinking water in 388 households and 381 samples from 66 water sources. V. cholerae was detected in 10% of point-of-drinking water samples and in 9% of source water samples. Twenty-three percent of households and 38% of the sources were positive for V. cholerae in at least one visit. Samples collected from point-of-drinking and linked sources in a 7 day interval showed significantly higher odds ( P source [OR = 17.24 (95% CI = 7.14-42.89)] water. Based on the 7 day interval data, 53% (17/32) of source water samples were negative for V. cholerae while linked point-of-drinking water samples were positive. There were significantly higher odds ( p source water samples than in point-of-drinking water samples. Contamination of water at the point-of-drinking is less likely to depend on the contamination at the water source. Hygiene education interventions and programs should focus and emphasize on water at the point

  4. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    Energy Technology Data Exchange (ETDEWEB)

    Yalcin, S. [Education Faculty, Kastamonu University, 37200 Kastamonu (Turkey)], E-mail: yalcin@gazi.edu.tr; Gurler, O.; Kaynak, G. [Department of Physics, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Department of Physics, School of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-10-15

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature.

  5. Calculation of total counting efficiency of a NaI(Tl) detector by hybrid Monte-Carlo method for point and disk sources

    International Nuclear Information System (INIS)

    Yalcin, S.; Gurler, O.; Kaynak, G.; Gundogdu, O.

    2007-01-01

    This paper presents results on the total gamma counting efficiency of a NaI(Tl) detector from point and disk sources. The directions of photons emitted from the source were determined by Monte-Carlo techniques and the photon path lengths in the detector were determined by analytic equations depending on photon directions. This is called the hybrid Monte-Carlo method where analytical expressions are incorporated into the Monte-Carlo simulations. A major advantage of this technique is the short computation time compared to other techniques on similar computational platforms. Another advantage is the flexibility for inputting detector-related parameters (such as source-detector distance, detector radius, source radius, detector linear attenuation coefficient) into the algorithm developed, thus making it an easy and flexible method to apply to other detector systems and configurations. The results of the total counting efficiency model put forward for point and disc sources were compared with the previous work reported in the literature

  6. 18O isotopic characterisation of non-point source contributed heavy metals (Zn and Cu) contamination of groundwater

    International Nuclear Information System (INIS)

    Datta, P.S.; Manjaiah, K.M.; Tyagi, S.K.

    1999-01-01

    In many urbanised areas, fast depletion and severe degradation of the of groundwater resource with contaminants such as nitrate, fluoride, and heavy metals is a common phenomenon, resulting in zonal disparity in fresh water availability. Therefore, for protection of groundwater from pollution and depletion, it is a matter of concern for the planners and decision makers to clearly characterise the sources of contamination and to search for an alternative approach for groundwater development and management. In this context, a new approach is presented here, based on monitoring of 18 O stable isotopic and heavy metals composition of groundwater, to clearly characterise non-point source contributed heavy metals pollution of groundwater in northern parts of Delhi area. In the investigated area, the Cu content in the groundwater ranges from 3-41 μg/l and Zn content ranges from 5-182 μg/l, showing considerable variation from location to location as well as within the small parts of a location. Wide variation in the 18 O stable isotope content of groundwater (δ value of -5.7 per mille to -8.5 per mille) is due to significant variation in the δ 18 O-contents of rainfall with space and time, as well as intensity and distribution of rainfall. Enrichment in 18 O composition with increasing Cu and Zn levels in groundwater suggest that infiltration of rain water, irrigation water and surface run-off water from the surrounding farm lands, along with agrochemicals and other salts present in the soil, to be the main processes causing groundwater contamination. The concentration of Cu and Zn in groundwater vary spatially, due to different degrees of evaporation/recharge, amounts of fertiliser applied and wastes disposed, adsorption/dispersion of species in the soils and lateral mixing of groundwater. Two opposite mechanisms adsorption and redistribution of infiltrating water along with Zn and Cu species in the soil zone are likely to affect the movement of the Zn and Cu species

  7. Alaska earthquake source for the SAFRR tsunami scenario: Chapter B in The SAFRR (Science Application for Risk Reduction) Tsunami Scenario

    Science.gov (United States)

    Kirby, Stephen; Scholl, David; von Huene, Roland E.; Wells, Ray

    2013-01-01

    Tsunami modeling has shown that tsunami sources located along the Alaska Peninsula segment of the Aleutian-Alaska subduction zone have the greatest impacts on southern California shorelines by raising the highest tsunami waves for a given source seismic moment. The most probable sector for a Mw ~ 9 source within this subduction segment is between Kodiak Island and the Shumagin Islands in what we call the Semidi subduction sector; these bounds represent the southwestern limit of the 1964 Mw 9.2 Alaska earthquake rupture and the northeastern edge of the Shumagin sector that recent Global Positioning System (GPS) observations indicate is currently creeping. Geological and geophysical features in the Semidi sector that are thought to be relevant to the potential for large magnitude, long-rupture-runout interplate thrust earthquakes are remarkably similar to those in northeastern Japan, where the destructive Mw 9.1 tsunamigenic earthquake of 11 March 2011 occurred. In this report we propose and justify the selection of a tsunami source seaward of the Alaska Peninsula for use in the Tsunami Scenario that is part of the U.S. Geological Survey (USGS) Science Application for Risk Reduction (SAFRR) Project. This tsunami source should have the potential to raise damaging tsunami waves on the California coast, especially at the ports of Los Angeles and Long Beach. Accordingly, we have summarized and abstracted slip distribution from the source literature on the 2011 event, the best characterized for any subduction earthquake, and applied this synoptic slip distribution to the similar megathrust geometry of the Semidi sector. The resulting slip model has an average slip of 18.6 m and a moment magnitude of Mw = 9.1. The 2011 Tohoku earthquake was not anticipated, despite Japan having the best seismic and geodetic networks in the world and the best historical record in the world over the past 1,500 years. What was lacking was adequate paleogeologic data on prehistoric earthquakes

  8. Non-point source pollution of glyphosate and AMPA in a rural basin from the southeast Pampas, Argentina.

    Science.gov (United States)

    Okada, Elena; Pérez, Débora; De Gerónimo, Eduardo; Aparicio, Virginia; Massone, Héctor; Costa, José Luis

    2018-05-01

    We measured the occurrence and seasonal variations of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), in different environmental compartments within the limits of an agricultural basin. This topic is of high relevance since glyphosate is the most applied pesticide in agricultural systems worldwide. We were able to quantify the seasonal variations of glyphosate that result mainly from endo-drift inputs, that is, from direct spraying either onto genetically modified (GM) crops (i.e., soybean and maize) or onto weeds in no-till practices. We found that both glyphosate and AMPA accumulate in soil, but the metabolite accumulates to a greater extent due to its higher persistence. Knowing that glyphosate and AMPA were present in soils (> 93% of detection for both compounds), we aimed to study the dispersion to other environmental compartments (surface water, stream sediments, and groundwater), in order to establish the degree of non-point source pollution. Also, we assessed the relationship between the water-table depth and glyphosate and AMPA levels in groundwater. All of the studied compartments had variable levels of glyphosate and AMPA. The highest frequency of detections was found in the stream sediments samples (glyphosate 95%, AMPA 100%), followed by surface water (glyphosate 28%, AMPA 50%) and then groundwater (glyphosate 24%, AMPA 33%). Despite glyphosate being considered a molecule with low vertical mobility in soils, we found that its detection in groundwater was strongly associated with the month where glyphosate concentration in soil was the highest. However, we did not find a direct relation between groundwater table depth and glyphosate or AMPA detections. This is the first simultaneous study of glyphosate and AMPA seasonal variations in soil, groundwater, surface water, and sediments within a rural basin.

  9. Assessing the effects of rural livelihood transition on non-point source pollution: a coupled ABM-IECM model.

    Science.gov (United States)

    Yuan, Chengcheng; Liu, Liming; Ye, Jinwei; Ren, Guoping; Zhuo, Dong; Qi, Xiaoxing

    2017-05-01

    Water pollution caused by anthropogenic activities and driven by changes in rural livelihood strategies in an agricultural system has received increasing attention in recent decades. To simulate the effects of rural household livelihood transition on non-point source (NPS) pollution, a model combining an agent-based model (ABM) and an improved export coefficient model (IECM) was developed. The ABM was adopted to simulate the dynamic process of household livelihood transition, and the IECM was employed to estimate the effects of household livelihood transition on NPS pollution. The coupled model was tested in a small catchment in the Dongting Lake region, China. The simulated results reveal that the transition of household livelihood strategies occurred with the changes in the prices of rice, pig, and labor. Thus, the cropping system, land-use intensity, resident population, and number of pigs changed in the small catchment from 2000 to 2014. As a result of these changes, the total nitrogen load discharged into the river initially increased from 6841.0 kg in 2000 to 8446.3 kg in 2004 and then decreased to 6063.9 kg in 2014. Results also suggest that rural living, livestock, paddy field, and precipitation alternately became the main causes of NPS pollution in the small catchment, and the midstream region of the small catchment was the primary area for NPS pollution from 2000 to 2014. Despite some limitations, the coupled model provides an innovative way to simulate the effects of rural household livelihood transition on NPS pollution with the change of socioeconomic factors, and thereby identify the key factors influencing water pollution to provide valuable suggestions on how agricultural environmental risks can be reduced through the regulation of the behaviors of farming households in the future.

  10. [Empirical study on non-point sources pollution based on landscape pattern & ecological processes theory: a case of soil water loss on the Loess Plateau in China].

    Science.gov (United States)

    Suo, An-ning; Wang, Tian-ming; Wang, Hui; Yu, Bo; Ge, Jian-ping

    2006-12-01

    Non-point sources pollution is one of main pollution modes which pollutes the earth surface environment. Aimed at soil water loss (a typical non-point sources pollution problem) on the Losses Plateau in China, the paper applied a landscape patternevaluation method to twelve watersheds of Jinghe River Basin on the Loess Plateau by means of location-weighted landscape contrast index(LCI) and landscape slope index(LSI). The result showed that LSI of farm land, low density grass land, forest land and LCI responded significantly to soil erosion modulus and responded to depth of runoff, while the relationship between these landscape index and runoff variation index and erosion variation index were not statistically significant. This tell us LSI and LWLCI are good indicators of soil water loss and thus have big potential in non-point source pollution risk evaluation.

  11. Reduction of Methane Emission during Slurry Storage by the Addition of Effective Microorganisms and Excessive Carbon Source from Brewing Sugar.

    Science.gov (United States)

    Bastami, Mohd Saufi B; Jones, Davey L; Chadwick, David R

    2016-11-01

    Storing livestock manure is the primary stage of manure management where microbial processes and chemical reactions result in the release of methane (CH), nitrous oxide (NO), ammonia (NH), and carbon dioxide (CO). This study examined the reduction of CH emissions from slurry storage under two temperatures (cool [10°C] and warm [30°C]) when a glucose-rich substrate (brewing sugar) and activated effective microorganisms were applied at 10% (w/w) and 5% (v/w), respectively. Brewing sugar addition influenced microbial anaerobic respiration, resulting in a reduction of slurry pH to <5.0, through "self-acidification" caused by lactic acid production. Subsequently, CH emissions were significantly reduced by 87 and 99% in the cool and warm environments, respectively. The effective microorganism treatment did not change the chemical characteristics of the slurry but reduced CH emissions by 17 and 27% ( < 0.05) in the cool and warm environments, respectively. These results suggest that self-acidification after addition of a carbon source may be a promising alternative to slurry acidification using concentrated acids. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  12. Taming a Tiger in the City: Comparison of Motorized Backpack Applications and Source Reduction Against the Asian Tiger Mosquito, Aedes albopictus

    Science.gov (United States)

    2014-06-01

    TAMING A TIGER IN THE CITY: COMPARISON OF MOTORIZED BACKPACK APPLICATIONS AND SOURCE REDUCTION AGAINST THE ASIAN TIGER MOSQUITO, AEDES ALBOPICTUS...FONSECA2 AND ARY FARAJOLLAHI2,3,7 ABSTRACT. We evaluated 2 strategies to manage Aedes albopictus: 1) motorized backpack applications and 2) source...the community level. KEY WORDS Bacillus thuringiensis israelensis, Bti, methoprene, hand applications, backpack applications INTRODUCTION Aedes

  13. Performance summary on a high power dense plasma focus x-ray lithography point source producing 70 nm line features in AlGaAs microcircuits

    International Nuclear Information System (INIS)

    Petr, Rodney; Bykanov, Alexander; Freshman, Jay; Reilly, Dennis; Mangano, Joseph; Roche, Maureen; Dickenson, Jason; Burte, Mitchell; Heaton, John

    2004-01-01

    A high average power dense plasma focus (DPF), x-ray point source has been used to produce ∼70 nm line features in AlGaAs-based monolithic millimeter-wave integrated circuits (MMICs). The DPF source has produced up to 12 J per pulse of x-ray energy into 4π steradians at ∼1 keV effective wavelength in ∼2 Torr neon at pulse repetition rates up to 60 Hz, with an effective x-ray yield efficiency of ∼0.8%. Plasma temperature and electron concentration are estimated from the x-ray spectrum to be ∼170 eV and ∼5·10 19 cm -3 , respectively. The x-ray point source utilizes solid-state pulse power technology to extend the operating lifetime of electrodes and insulators in the DPF discharge. By eliminating current reversals in the DPF head, an anode electrode has demonstrated a lifetime of more than 5 million shots. The x-ray point source has also been operated continuously for 8 h run times at 27 Hz average pulse recurrent frequency. Measurements of shock waves produced by the plasma discharge indicate that overpressure pulses must be attenuated before a collimator can be integrated with the DPF point source

  14. The rise in the positron fraction. Distance limits on positron point sources from cosmic ray arrival directions and diffuse gamma-rays

    Energy Technology Data Exchange (ETDEWEB)

    Gebauer, Iris; Bentele, Rosemarie [Karlsruhe Institute of Technology, Karlsruhe (Germany)

    2016-07-01

    The rise in the positron fraction as observed by AMS and previously by PAMELA, cannot be explained by the standard paradigm of cosmic ray transport in which positrons are produced by cosmic-ray-gas interactions in the interstellar medium. Possible explanations are pulsars, which produce energetic electron-positron pairs in their rotating magnetic fields, or the annihilation of dark matter. Here we assume that these positrons originate from a single close-by point source, producing equal amounts of electrons and positrons. The propagation and energy losses of these electrons and positrons are calculated numerically using the DRAGON code, the source properties are optimized to best describe the AMS data. Using the FERMI-LAT limits on a possible dipole anisotropy in electron and positron arrival directions, we put a limit on the minimum distance of such a point source. The energy losses that these energetic electrons and positrons suffer on their way through the galaxy create gamma ray photons through bremsstrahlung and Inverse Compton scattering. Using the measurement of diffuse gamma rays from Fermi-LAT we put a limit on the maximum distance of such a point source. We find that a single electron positron point source powerful enough to explain the locally observed positron fraction must reside between 225 pc and 3.7 kpc distance from the sun and compare to known pulsars.

  15. Catalysts for cleaner combustion of coal, wood and briquettes sulfur dioxide reduction options for low emission sources

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P.V. [Global Environmental Solutions, Inc., Morton Grove, IL (United States)

    1995-12-31

    Coal fired, low emission sources are a major factor in the air quality problems facing eastern European cities. These sources include: stoker-fired boilers which feed district heating systems and also meet local industrial steam demand, hand-fired boilers which provide heat for one building or a small group of buildings, and masonary tile stoves which heat individual rooms. Global Environmental Systems is marketing through Global Environmental Systems of Polane, Inc. catalysts to improve the combustion of coal, wood or fuel oils in these combustion systems. PCCL-II Combustion Catalysts promotes more complete combustion, reduces or eliminates slag formations, soot, corrosion and some air pollution emissions and is especially effective on high sulfur-high vanadium residual oils. Glo-Klen is a semi-dry powder continuous acting catalyst that is injected directly into the furnace of boilers by operating personnel. It is a multi-purpose catalyst that is a furnace combustion catalyst that saves fuel by increasing combustion efficiency, a cleaner of heat transfer surfaces that saves additional fuel by increasing the absorption of heat, a corrosion-inhibiting catalyst that reduces costly corrosion damage and an air pollution reducing catalyst that reduces air pollution type stack emissions. The reduction of sulfur dioxides from coal or oil-fired boilers of the hand fired stoker design and larger, can be controlled by the induction of the Glo-Klen combustion catalyst and either hydrated lime or pulverized limestone.

  16. Methane and CO2 fluxes of moving point sources - Beyond or within the limits of eddy covariance measurements

    Science.gov (United States)

    Felber, Raphael; Neftel, Albrecht; Münger, Andreas; Ammann, Christof

    2014-05-01

    The eddy covariance (EC) technique has been extensively used for CO2 and energy exchange measurements over different ecosystems. For some years, it has been also becoming widely used to investigate CH4 and N2O exchange over ecosystems including grazing systems. EC measurements represent a spatially integrated flux over an upwind area (footprint). Whereas for extended homogenous areas EC measurements work well, the animals in a grazing system are a challenge as they represent moving point sources that create inhomogeneous conditions in space and time. The main issues which have to be taken into account when applying EC flux measurements over a grazed system are: i) In the presence of animals the high time resolution concentration measurements show large spikes in the signal. These spikes may be filtered/reduced by standard quality control software in order to avoid wrong measurements. ii) Data on the position of the animals relative to the flux footprint is needed to quantify the contribution of the grazing animals to the measured flux. For one grazing season we investigated the ability of EC flux measurements to reliably quantify the contribution of the grazing animals to the CH4 and CO2 exchange over pasture systems. For this purpose, a field experiment with a herd of twenty dairy cows in a full-day rotational grazing system was carried out on the Swiss central plateau. Net CH4 and CO2 exchange of the pasture system was measured continuously by the eddy covariance technique (Sonic Anemometer HS-50, Gill Instruments Ltd; FGGA, Los Gatos Research Inc.). To quantify the contribution of the animals to the net flux, the position of the individual cows was recorded using GPS (5 s time resolution) on each animal. An existing footprint calculation tool (ART footprint tool) was adapted and CH4 emissions of the cows were calculated. CH4 emissions from cows could be used as a tracer to investigate the quality of the evaluation of the EC data, since the background exchange of

  17. Macro and micro plastics sorb and desorb metals and act as a point source of trace metals to coastal ecosystems.

    Directory of Open Access Journals (Sweden)

    B Munier

    . Plastic debris will affect metals within coastal ecosystems by; 1 providing a sorption site (copper and lead, notably for PVC 2 desorption from the plastic i.e., the "inherent" load (cadmium and zinc and 3 serving as a point source of acute trace metal exposure to coastal ecosystems. All three mechanisms will put coastal ecosystems at risk to the toxic effects of these metals.

  18. SU-F-T-15: Evaluation of 192Ir, 60Co and 169Yb Sources for High Dose Rate Prostate Brachytherapy Inverse Planning Using An Interior Point Constraint Generation Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Mok Tsze Chung, E; Aleman, D [University of Toronto, Toronto, Ontario (Canada); Safigholi, H; Nicolae, A; Davidson, M; Ravi, A; Song, W [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario (Canada)

    2016-06-15

    Purpose: The effectiveness of using a combination of three sources, {sup 60}Co, {sup 192}Ir and {sup 169}Yb, is analyzed. Different combinations are compared against a single {sup 192}Ir source on prostate cancer cases. A novel inverse planning interior point algorithm is developed in-house to generate the treatment plans. Methods: Thirteen prostate cancer patients are separated into two groups: Group A includes eight patients with the prostate as target volume, while group B consists of four patients with a boost nodule inside the prostate that is assigned 150% of the prescription dose. The mean target volume is 35.7±9.3cc and 30.6±8.5cc for groups A and B, respectively. All patients are treated with each source individually, then with paired sources, and finally with all three sources. To compare the results, boost volume V150 and D90, urethra Dmax and D10, and rectum Dmax and V80 are evaluated. For fair comparison, all plans are normalized to a uniform V100=100. Results: Overall, double- and triple-source plans were better than single-source plans. The triple-source plans resulted in an average decrease of 21.7% and 1.5% in urethra Dmax and D10, respectively, and 8.0% and 0.8% in rectum Dmax and V80, respectively, for group A. For group B, boost volume V150 and D90 increased by 4.7% and 3.0%, respectively, while keeping similar dose delivered to the urethra and rectum. {sup 60}Co and {sup 192}Ir produced better plans than their counterparts in the double-source category, whereas {sup 60}Co produced more favorable results than the remaining individual sources. Conclusion: This study demonstrates the potential advantage of using a combination of two or three sources, reflected in dose reduction to organs-at-risk and more conformal dose to the target. three sources, reflected in dose reduction to organs-at-risk and more conformal dose to the target. Our results show that {sup 60}Co, {sup 192}Ir and {sup 169}Yb produce the best plans when used simultaneously and

  19. Effect of exposure history on microbial herbicide degradation in an aerobic aquifer affected by a point source

    DEFF Research Database (Denmark)

    Tuxen, Nina; de Lipthay, J.R.; Albrechtsen, Hans-Jørgen

    2002-01-01

    sampling points from within the plume, and neither BAM, bentazone, nor isoproturon was degraded in any sampling point. A linear correlation (R2 g 0.83) between pre-exposure and amount of herbicide degraded within 50 days was observed for the phenoxy acids, mecoprop and dichlorprop. An improved model fit...

  20. Study on the quantitative relationship between Agricultural water and fertilization process and non-point source pollution based on field experiments

    Science.gov (United States)

    Wang, H.; Chen, K.; Wu, Z.; Guan, X.

    2017-12-01

    In recent years, with the prominent of water environment problem and the relative increase of point source pollution governance, especially the agricultural non-point source pollution problem caused by the extensive use of fertilizers and pesticides has become increasingly aroused people's concern and attention. In order to reveal the quantitative relationship between agriculture water and fertilizer and non-point source pollution, on the basis of elm field experiment and combined with agricultural drainage irrigation model, the agricultural irrigation water and the relationship between fertilizer and fertilization scheme and non-point source pollution were analyzed and calculated by field emission intensity index. The results show that the variation of displacement varies greatly under different irrigation conditions. When the irrigation water increased from 22cm to 42cm, the irrigation water increased by 20 cm while the field displacement increased by 11.92 cm, about 66.22% of the added value of irrigation water. Then the irrigation water increased from 42 to 68, irrigation water increased 26 cm, and the field displacement increased by 22.48 cm, accounting for 86.46% of irrigation water. So there is an "inflection point" between the irrigation water amount and field displacement amount. The load intensity increases with the increase of irrigation water and shows a significant power correlation. Under the different irrigation condition, the increase amplitude of load intensity with the increase of irrigation water is different. When the irrigation water is smaller, the load intensity increase relatively less, and when the irrigation water increased to about 42 cm, the load intensity will increase considerably. In addition, there was a positive correlation between the fertilization and load intensity. The load intensity had obvious difference in different fertilization modes even with same fertilization level, in which the fertilizer field unit load intensity

  1. Technical evaluation of the proposed changes in the technical specifications for emergency power sources for the Big Rock Point nuclear power plant

    International Nuclear Information System (INIS)

    Latorre, V.R.

    1979-12-01

    The technical evaluation is presented for the proposed changes to the Technical Specifications for emergency power sources for the Big Rock Point nuclear power plant. The criteria used to evaluate the acceptability of the changes include those delineated in IEEE Std-308-1974, and IEEE Std-450-1975 as endorsed by US NRC Regulatory Guide 1.129

  2. Micro-simulation as a tool to assess policy concerning non-point source pollution: the case of ammonia in Dutch agriculture

    NARCIS (Netherlands)

    Kruseman, G.; Blokland, P.W.; Bouma, F.; Luesink, H.H.; Vrolijk, H.C.J.

    2008-01-01

    Non-point source pollution is notoriously difficult to asses. A relevant example is ammonia emissions in the Netherlands. Since the mid 1980s the Dutch government has sought to reduce emissions through a wide variety of measures, the effect of which in turn is monitored using modeling techniques.