A cryogenic thermal source for detector array characterization

Science.gov (United States)

Chuss, David T.; Rostem, Karwan; Wollack, Edward J.; Berman, Leah; Colazo, Felipe; DeGeorge, Martin; Helson, Kyle; Sagliocca, Marco

2017-10-01

We describe the design, fabrication, and validation of a cryogenically compatible quasioptical thermal source for characterization of detector arrays. The source is constructed using a graphite-loaded epoxy mixture that is molded into a tiled pyramidal structure. The mold is fabricated using a hardened steel template produced via a wire electron discharge machining process. The absorptive mixture is bonded to a copper backplate enabling thermalization of the entire structure and measurement of the source temperature. Measurements indicate that the reflectance of the source is <0.001 across a spectral band extending from 75 to 330 GHz.

Characterization and source apportionment of water pollution in Jinjiang River, China.

Science.gov (United States)

Chen, Haiyang; Teng, Yanguo; Yue, Weifeng; Song, Liuting

2013-11-01

Characterizing water quality and identifying potential pollution sources could greatly improve our knowledge about human impacts on the river ecosystem. In this study, fuzzy comprehensive assessment (FCA), pollution index (PI), principal component analysis (PCA), and absolute principal component score-multiple linear regression (APCS-MLR) were combined to obtain a deeper understanding of temporal-spatial characterization and sources of water pollution with a case study of the Jinjiang River, China. Measurement data were obtained with 17 water quality variables from 20 sampling sites in the December 2010 (withered water period) and June 2011 (high flow period). FCA and PI were used to comprehensively estimate the water quality variables and compare temporal-spatial variations, respectively. Rotated PCA and receptor model (APCS-MLR) revealed potential pollution sources and their corresponding contributions. Application results showed that comprehensive application of various multivariate methods were effective for water quality assessment and management. In the withered water period, most sampling sites were assessed as low or moderate pollution with characteristics pollutants of permanganate index and total nitrogen (TN), whereas 90% sites were classified as high pollution in the high flow period with higher TN and total phosphorus. Agricultural non-point sources, industrial wastewater discharge, and domestic sewage were identified as major pollution sources. Apportionment results revealed that most variables were complicatedly influenced by industrial wastewater discharge and agricultural activities in withered water period and primarily dominated by agricultural runoff in high flow period.

Aero particles characterization emitted by mobile sources

International Nuclear Information System (INIS)

Rojas V, A.; Romero G, E. T.; Lopez G, H.

2009-01-01

In our country, the mobile sources that conform most of the emissions at the atmosphere, are concentrated on the urban areas. For the present work, samples coming from the escapes of terrestrial transport were obtained, such as: passenger buses, load transport and particular vehicles of the Metropolitan area of the Toluca valley. The material was analyzed by means of scanning electron microscopy of low vacuum and X-ray diffraction. The objective was to characterize the emitted particles by mobile sources, morphological and chemically to know the structure, size and elements that compose them. (Author)

Stress Wave Source Characterization: Impact, Fracture, and Sliding Friction

Science.gov (United States)

McLaskey, Gregory Christofer

Rapidly varying forces, such as those associated with impact, rapid crack propagation, and fault rupture, are sources of stress waves which propagate through a solid body. This dissertation investigates how properties of a stress wave source can be identified or constrained using measurements recorded at an array of sensor sites located far from the source. This methodology is often called the method of acoustic emission and is useful for structural health monitoring and the noninvasive study of material behavior such as friction and fracture. In this dissertation, laboratory measurements of 1--300 mm wavelength stress waves are obtained by means of piezoelectric sensors which detect high frequency (10 kHz--3MHz) motions of a specimen's surface, picometers to nanometers in amplitude. Then, stress wave source characterization techniques are used to study ball impact, drying shrinkage cracking in concrete, and the micromechanics of stick-slip friction of Poly(methyl methacrylate) (PMMA) and rock/rock interfaces. In order to quantitatively relate recorded signals obtained with an array of sensors to a particular stress wave source, wave propagation effects and sensor distortions must be accounted for. This is achieved by modeling the physics of wave propagation and transduction as linear transfer functions. Wave propagation effects are precisely modeled by an elastodynamic Green's function, sensor distortion is characterized by an instrument response function, and the stress wave source is represented with a force moment tensor. These transfer function models are verified though calibration experiments which employ two different mechanical calibration sources: ball impact and glass capillary fracture. The suitability of the ball impact source model, based on Hertzian contact theory, is experimentally validated for small (˜1 mm) balls impacting massive plates composed of four different materials: aluminum, steel, glass, and PMMA. Using this transfer function approach

Characterization of the near-source population around five ...

Science.gov (United States)

Many ports are currently preparing for increased freight traffic, which may result in elevated local air pollution in areas near the port and freight transportation corridors. In this study, a geographical information system (GIS) analysis of areas surrounding five ports – Port of New York and New Jersey, Port of Virginia, Port of Savannah, Port of Miami, and Port of Houston – was conducted to characterize the population that might be affected by air emissions from the freight transportation network and to determine which sources had the potential to affect the most people. Defining “near-source” populations as living within 300 m of the freight transportation network, namely the port and associated truck routes, railroads, and intermodal facilities (e. g. rail yards and warehouses); near-source populations ranged from 37,000 to over a million within 10 km of a port. At the ports considered, the population living within 300 m of the port boundary constituted of the total near-source population. Sensitive population exposure was also indicated, such as the 81 day care centers and K-12 schools in near-source environments within 2 km of the Port of New York and New Jersey. Minority groups constituted 55 % to 85 % of the near-source populations in the five port areas. For four of the five ports, the mean and median income of the near-source population was lower and the minority percentage was higher than the population living adjacent to the near-sou

Integrated Characterization of DNAPL Source Zone Architecture in Clay Till and Limestone Bedrock

DEFF Research Database (Denmark)

Broholm, Mette Martina; Janniche, Gry Sander; Fjordbøge, Annika Sidelmann

2014-01-01

Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives. The activi......Background/Objectives. Characterization of dense non-aqueous phase liquid (DNAPL) source zone architecture is essential to develop accurate site specific conceptual models, delineate and quantify contaminant mass, perform risk assessment, and select and design remediation alternatives...... innovative investigation methods and characterize the source zone hydrogeology and contamination to obtain an improved conceptual understanding of DNAPL source zone architecture in clay till and bryozoan limestone bedrock. Approach/Activities. A wide range of innovative and current site investigative tools...... for direct and indirect documentation and/or evaluation of DNAPL presence were combined in a multiple lines of evidence approach. Results/Lessons Learned. Though no single technique was sufficient for characterization of DNAPL source zone architecture, the combined use of membrane interphase probing (MIP...

X-ray intensity and source size characterizations for the 25 kV upgraded Manson source at Sandia National Laboratories

Energy Technology Data Exchange (ETDEWEB)

Loisel, G., E-mail: gploise@sandia.gov; Lake, P.; Gard, P.; Dunham, G.; Nielsen-Weber, L.; Wu, M. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Norris, E. [Missouri University of Science and Technology, Rolla, Missouri 65409 (United States)

2016-11-15

At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source. As the voltage increases, the source size is significantly reduced and line intensity is increased for the three materials. We can take advantage of the smaller source size and higher source throughput to effectively calibrate the suite of Z Pulsed Power Facility crystal spectrometers.

X-ray intensity and source size characterizations for the 25 kV upgraded Manson source at Sandia National Laboratories.

Science.gov (United States)

Loisel, G; Lake, P; Gard, P; Dunham, G; Nielsen-Weber, L; Wu, M; Norris, E

2016-11-01

At Sandia National Laboratories, the x-ray generator Manson source model 5 was upgraded from 10 to 25 kV. The purpose of the upgrade is to drive higher characteristics photon energies with higher throughput. In this work we present characterization studies for the source size and the x-ray intensity when varying the source voltage for a series of K-, L-, and M-shell lines emitted from Al, Y, and Au elements composing the anode. We used a 2-pinhole camera to measure the source size and an energy dispersive detector to monitor the spectral content and intensity of the x-ray source. As the voltage increases, the source size is significantly reduced and line intensity is increased for the three materials. We can take advantage of the smaller source size and higher source throughput to effectively calibrate the suite of Z Pulsed Power Facility crystal spectrometers.

Characterizing sources of emissions from wildland fires

Science.gov (United States)

Roger D. Ottmar; Ana Isabel Miranda; David V. Sandberg

2009-01-01

Smoke emissions from wildland fire can be harmful to human health and welfare, impair visibility, and contribute to greenhouse gas emissions. The generation of emissions and heat release need to be characterized to estimate the potential impacts of wildland fire smoke. This requires explicit knowledge of the source, including size of the area burned, burn period,...

Developing a source-receptor methodology for the characterization of VOC sources in ambient air

International Nuclear Information System (INIS)

Borbon, A.; Badol, C.; Locoge, N.

2005-01-01

Since 2001, in France, a continuous monitoring of about thirty ozone precursor non-methane hydrocarbons (NMHC) is led in some urban areas. The automated system for NMHC monitoring consists of sub-ambient preconcentration on a cooled multi-sorbent trap followed by thermal desorption and bidimensional Gas Chromatography/Flame Ionisation Detection analysis.The great number of data collected and their exploitation should provide a qualitative and quantitative assessment of hydrocarbon sources. This should help in the definition of relevant strategies of emission regulation as stated by the European Directive relative to ozone in ambient air (2002/3/EC). The purpose of this work is to present the bases and the contributions of an original methodology known as source-receptor in the characterization of NMHC sources. It is a statistical and diagnostic approach, adaptable and transposable in all urban sites, which integrates the spatial and temporal dynamics of the emissions. The methods for source identification combine descriptive or more complex complementary approaches: 1) univariate approach through the analysis of NMHC time series and concentration roses, 2) bivariate approach through a Graphical Ratio Analysis and a characterization of scatterplot distributions of hydrocarbon pairs, 3) multivariate approach with Principal Component Analyses on various time basis. A linear regression model is finally developed to estimate the spatial and temporal source contributions. Apart from vehicle exhaust emissions, sources of interest are: combustion and fossil fuel-related activities, petrol and/or solvent evaporation, the double anthropogenic and biogenic origin of isoprene and other industrial activities depending on local parameters. (author)

Development and characterization of electron sources for diffraction applications

International Nuclear Information System (INIS)

Casandruc, Albert

2015-12-01

The dream to control chemical reactions that are essential to life is now closer than ever to gratify. Recent scientific progress has made it possible to investigate phenomena and processes which deploy at the angstroms scale and at rates on the order femtoseconds. Techniques such as Ultrafast Electron Diffraction (UED) are currently able to reveal the spatial atomic configuration of systems with unit cell sizes on the order of a few nanometers with about 100 femtosecond temporal resolution. Still, major advances are needed for structural interrogation of biological systems like protein crystals, which have unit cell sizes of 10 nanometers or larger, and sample sizes of less than one micrometer. For such samples, the performance of these electron-based techniques is now limited by the quality, in particular the brightness, of the electron source. The current Ph.D. work represents a contribution towards the development and the characterization of electron sources which are essential to static and time-resolved electron diffraction techniques. The focus was on electron source fabrication and electron beam characterization measurements, using the solenoid and the aperture scan techniques, but also on the development and maintenance of the relevant experimental setups. As a result, new experimental facilities are now available in the group and, at the same time, novel concepts for generating electron beams for electron diffraction applications have been developed. In terms of existing electron sources, the capability to trigger and detect field emission from single double-gated field emitter Mo tips was successfully proven. These sharp emitter tips promise high brightness electron beams, but for investigating individual such structures, new engineering was needed. Secondly, the influence of the surface electric field on electron beam properties has been systematically performed for flat Mo photocathodes. This study is very valuable especially for state

Development and characterization of electron sources for diffraction applications

Energy Technology Data Exchange (ETDEWEB)

Casandruc, Albert

2015-12-15

The dream to control chemical reactions that are essential to life is now closer than ever to gratify. Recent scientific progress has made it possible to investigate phenomena and processes which deploy at the angstroms scale and at rates on the order femtoseconds. Techniques such as Ultrafast Electron Diffraction (UED) are currently able to reveal the spatial atomic configuration of systems with unit cell sizes on the order of a few nanometers with about 100 femtosecond temporal resolution. Still, major advances are needed for structural interrogation of biological systems like protein crystals, which have unit cell sizes of 10 nanometers or larger, and sample sizes of less than one micrometer. For such samples, the performance of these electron-based techniques is now limited by the quality, in particular the brightness, of the electron source. The current Ph.D. work represents a contribution towards the development and the characterization of electron sources which are essential to static and time-resolved electron diffraction techniques. The focus was on electron source fabrication and electron beam characterization measurements, using the solenoid and the aperture scan techniques, but also on the development and maintenance of the relevant experimental setups. As a result, new experimental facilities are now available in the group and, at the same time, novel concepts for generating electron beams for electron diffraction applications have been developed. In terms of existing electron sources, the capability to trigger and detect field emission from single double-gated field emitter Mo tips was successfully proven. These sharp emitter tips promise high brightness electron beams, but for investigating individual such structures, new engineering was needed. Secondly, the influence of the surface electric field on electron beam properties has been systematically performed for flat Mo photocathodes. This study is very valuable especially for state

Source and LINAC3 studies

CERN Document Server

Bellodi, G

2017-01-01

In the framework of the LHC Ion Injector Upgrade pro-gramme (LIU), several activities have been carried out in2016 to improve the ion source and Linac3 performance,with the goal to increase the beam current routinely deliv-ered to LEIR. The extraction region of the GTS-LHC ionsource was upgraded with enlarged vacuum chamber aper-tures and the addition of an einzel lens, yielding highertransmission through the rest of the machine. Also, a seriesof experiments have been performed to study the effects ofdouble frequency mixing on the afterglow performance ofthe source after installation of a Travelling Wave Tube Am-plifier (TWTA) as secondary microwave source at variablefrequency. Measurements have been carried out at a dedi-cated oven test stand for better understanding of the ionsource performance. Finally, several MD sessions werededicated to the study and characterization of the strippingfoils, after evidence of degradation in time was discoveredin the 2015 run.

Exploring REACH as a potential data source for characterizing ecotoxicity in life cycle assessment

DEFF Research Database (Denmark)

Müller, Nienke; de Zwart, Dick; Hauschild, Michael Zwicky

2017-01-01

Toxicity models in life cycle impact assessment (LCIA) currently only characterize a small fraction of marketed substances, mostly because of limitations in the underlying ecotoxicity data. One approach to improve the current data situation in LCIA is to identify new data sources, such as the Eur......Toxicity models in life cycle impact assessment (LCIA) currently only characterize a small fraction of marketed substances, mostly because of limitations in the underlying ecotoxicity data. One approach to improve the current data situation in LCIA is to identify new data sources......, such as the European Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) database. The present study explored REACH as a potential data source for LCIA based on matching reported ecotoxicity data for substances that are currently also included in the United Nations Environment Programme....../Society for Environmental Toxicology and Chemistry (UNEP/SETAC) scientific consensus model USEtox for characterizing toxicity impacts. Data are evaluated with respect to number of data points, reported reliability, and test duration, and are compared with data listed in USEtox at the level of hazardous concentration for 50...

Characterization of the pulse plasma source

International Nuclear Information System (INIS)

Milosavljevic, V; Karkari, S K; Ellingboe, A R

2007-01-01

Characterization of the pulse plasma source through the determination of the local thermodynamic equilibrium (LTE) threshold is described. The maximum electron density measured at the peak in discharge current is determined by the width of the He II Paschen alpha spectral line, and the electron temperature is determined from the ratios of the relative intensities of spectral lines emitted from successive ionized stages of atoms. The electron density and temperature maximum values are measured to be 1.3 x 10 17 cm -3 and 19 000 K, respectively. These are typical characteristics for low-pressure, pulsed plasma sources for input energy of 15.8 J at 130 Pa pressure in helium-argon mixture. The use of LTE-based analysis of the emission spectra is justified by measurement of the local plasma electron density at four positions in the discharge tube using a floating hairpin resonance probe. The hairpin resonance probe data are collected during the creation and decay phases of the pulse. From the spatio-temporal profile of the plasma density a 60 μs time-window during which LTE exists throughout the entire plasma source is determined

Source characterization and exposure modeling of gas-phase polycyclic aromatic hydrocarbon (PAH) concentrations in Southern California

Science.gov (United States)

Masri, Shahir; Li, Lianfa; Dang, Andy; Chung, Judith H.; Chen, Jiu-Chiuan; Fan, Zhi-Hua (Tina); Wu, Jun

2018-03-01

Airborne exposures to polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health outcomes. Because personal air measurements of PAHs are labor intensive and costly, spatial PAH exposure models are useful for epidemiological studies. However, few studies provide adequate spatial coverage to reflect intra-urban variability of ambient PAHs. In this study, we collected 39-40 weekly gas-phase PAH samples in southern California twice in summer and twice in winter, 2009, in order to characterize PAH source contributions and develop spatial models that can estimate gas-phase PAH concentrations at a high resolution. A spatial mixed regression model was constructed, including such variables as roadway, traffic, land-use, vegetation index, commercial cooking facilities, meteorology, and population density. Cross validation of the model resulted in an R2 of 0.66 for summer and 0.77 for winter. Results showed higher total PAH concentrations in winter. Pyrogenic sources, such as fossil fuels and diesel exhaust, were the most dominant contributors to total PAHs. PAH sources varied by season, with a higher fossil fuel and wood burning contribution in winter. Spatial autocorrelation accounted for a substantial amount of the variance in total PAH concentrations for both winter (56%) and summer (19%). In summer, other key variables explaining the variance included meteorological factors (9%), population density (15%), and roadway length (21%). In winter, the variance was also explained by traffic density (16%). In this study, source characterization confirmed the dominance of traffic and other fossil fuel sources to total measured gas-phase PAH concentrations while a spatial exposure model identified key predictors of PAH concentrations. Gas-phase PAH source characterization and exposure estimation is of high utility to epidemiologist and policy makers interested in understanding the health impacts of gas-phase PAHs and strategies to reduce emissions.

Exploring REACH as a potential data source for characterizing ecotoxicity in life cycle assessment.

Science.gov (United States)

Müller, Nienke; de Zwart, Dick; Hauschild, Michael; Kijko, Gaël; Fantke, Peter

2017-02-01

Toxicity models in life cycle impact assessment (LCIA) currently only characterize a small fraction of marketed substances, mostly because of limitations in the underlying ecotoxicity data. One approach to improve the current data situation in LCIA is to identify new data sources, such as the European Registration, Evaluation, Authorisation, and Restriction of Chemicals (REACH) database. The present study explored REACH as a potential data source for LCIA based on matching reported ecotoxicity data for substances that are currently also included in the United Nations Environment Programme/Society for Environmental Toxicology and Chemistry (UNEP/SETAC) scientific consensus model USEtox for characterizing toxicity impacts. Data are evaluated with respect to number of data points, reported reliability, and test duration, and are compared with data listed in USEtox at the level of hazardous concentration for 50% of the covered species per substance. The results emphasize differences between data available via REACH and in USEtox. The comparison of ecotoxicity data from REACH and USEtox shows potential for using REACH ecotoxicity data in LCIA toxicity characterization, but also highlights issues related to compliance of submitted data with REACH requirements as well as different assumptions underlying regulatory risk assessment under REACH versus data needed for LCIA. Thus, further research is required to address data quality, pre-processing, and applicability, before considering data submitted under REACH as a data source for use in LCIA, and also to explore additionally available data sources, published studies, and reports. Environ Toxicol Chem 2017;36:492-500. © 2016 SETAC. © 2016 SETAC.

A simplified approach to characterizing a kilovoltage source spectrum for accurate dose computation

Energy Technology Data Exchange (ETDEWEB)

Poirier, Yannick; Kouznetsov, Alexei; Tambasco, Mauro [Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 4N2 (Canada); Department of Physics and Astronomy and Department of Oncology, University of Calgary and Tom Baker Cancer Centre, Calgary, Alberta T2N 4N2 (Canada)

2012-06-15

Purpose: To investigate and validate the clinical feasibility of using half-value layer (HVL) and peak tube potential (kVp) for characterizing a kilovoltage (kV) source spectrum for the purpose of computing kV x-ray dose accrued from imaging procedures. To use this approach to characterize a Varian Registered-Sign On-Board Imager Registered-Sign (OBI) source and perform experimental validation of a novel in-house hybrid dose computation algorithm for kV x-rays. Methods: We characterized the spectrum of an imaging kV x-ray source using the HVL and the kVp as the sole beam quality identifiers using third-party freeware Spektr to generate the spectra. We studied the sensitivity of our dose computation algorithm to uncertainties in the beam's HVL and kVp by systematically varying these spectral parameters. To validate our approach experimentally, we characterized the spectrum of a Varian Registered-Sign OBI system by measuring the HVL using a Farmer-type Capintec ion chamber (0.06 cc) in air and compared dose calculations using our computationally validated in-house kV dose calculation code to measured percent depth-dose and transverse dose profiles for 80, 100, and 125 kVp open beams in a homogeneous phantom and a heterogeneous phantom comprising tissue, lung, and bone equivalent materials. Results: The sensitivity analysis of the beam quality parameters (i.e., HVL, kVp, and field size) on dose computation accuracy shows that typical measurement uncertainties in the HVL and kVp ({+-}0.2 mm Al and {+-}2 kVp, respectively) source characterization parameters lead to dose computation errors of less than 2%. Furthermore, for an open beam with no added filtration, HVL variations affect dose computation accuracy by less than 1% for a 125 kVp beam when field size is varied from 5 Multiplication-Sign 5 cm{sup 2} to 40 Multiplication-Sign 40 cm{sup 2}. The central axis depth dose calculations and experimental measurements for the 80, 100, and 125 kVp energies agreed within

Installation and Characterization of Charged Particle Sources for Space Environmental Effects Testing

Science.gov (United States)

Skevington, Jennifer L.

2010-01-01

Charged particle sources are integral devices used by Marshall Space Flight Center s Environmental Effects Branch (EM50) in order to simulate space environments for accurate testing of materials and systems. By using these sources inside custom vacuum systems, materials can be tested to determine charging and discharging properties as well as resistance to sputter damage. This knowledge can enable scientists and engineers to choose proper materials that will not fail in harsh space environments. This paper combines the steps utilized to build a low energy electron gun (The "Skevington 3000") as well as the methods used to characterize the output of both the Skevington 3000 and a manufactured Xenon ion source. Such characterizations include beam flux, beam uniformity, and beam energy. Both sources were deemed suitable for simulating environments in future testing.

Characterization of carbonaceous aerosol emissions from selected combustion sources

International Nuclear Information System (INIS)

Martinez, J.P.G.; Espino, M.P.M.; Pabroa, P.C.B.; Bautista, A.T. VII

2015-01-01

Carbonaceous Particulates are carbon-containing solid or liquid matter which form a significant portion of the fine particulate mass (PM2.5) and these have known profound adverse effects on health, climate and visibility. This study aims to characterize carbonaceous aerosol emissions from different combustion sources to establish fingerprints for these for use in the refinement of improvement of the resolution of sources apportionment studies being done by the Philippine Nuclear Research Institute (PNRI), i.e. to resolve vehicular emission sources. Fine air particulate sample were collected in pre-baked Quartz filters using an improvised collection set-up with a Gent sampler. Concentrations of organic and elemental carbon (OC and EC, respectively) in PM2.5 were measured for the different combustion sources—vehicular emissions, tire pyrolysis, and biomass burning, using a thermal-optical method of analysis following the IMPROVE_A protocol. Measured OC ad EC concentrations are shown as percentages with respect to the total carbon (TC) and are illustrated in a 100% stacked chart. Predominance of the EC2 fraction is exhibited in both the diesel fuelled vehicle and tire pyrolysis emissions with EC2/OC2 ratio distinguishing one from the other, EC2/OC2 is 1.63 and 8.41, respectively. Predominance of either OC2 or OC3 fraction is shown in the unleaded gasoline and LPG Fuelled vehicles and in biomass burning with the OC2/OC3 ratio distinguishing one from the others. OC2/OC3 ratios are 1.33 for unleaded gasoline fuelled vehicle, 1.89 for LPG-fuelled vehicle, 0.55 for biomass burning (leaves) and 0.82 biomass burning (wood). The study has shown probable use of the EC2/OC2 and OC2/OC3 ratios to distinguish fingerprints for combustion sources covered in this study. (author)

A compact time-of-flight mass spectrometer for ion source characterization

International Nuclear Information System (INIS)

Chen, L.; Wan, X.; Jin, D. Z.; Tan, X. H.; Huang, Z. X.; Tan, G. B.

2015-01-01

A compact time-of-flight mass spectrometer with overall dimension of about 413 × 250 × 414 mm based on orthogonal injection and angle reflection has been developed for ion source characterization. Configuration and principle of the time-of-flight mass spectrometer are introduced in this paper. The mass resolution is optimized to be about 1690 (FWHM), and the ion energy detection range is tested to be between about 3 and 163 eV with the help of electron impact ion source. High mass resolution and compact configuration make this spectrometer useful to provide a valuable diagnostic for ion spectra fundamental research and study the mass to charge composition of plasma with wide range of parameters

Online Chemical Characterization of Food-Cooking Organic Aerosols: Implications for Source Apportionment.

Science.gov (United States)

Reyes-Villegas, Ernesto; Bannan, Thomas; Le Breton, Michael; Mehra, Archit; Priestley, Michael; Percival, Carl; Coe, Hugh; Allan, James D

2018-04-11

Food-cooking organic aerosols (COA) are one of the primary sources of submicron particulate matter in urban environments. However, there are still many questions surrounding source apportionment related to instrumentation as well as semivolatile partitioning because COA evolve rapidly in the ambient air, making source apportionment more complex. Online measurements of emissions from cooking different types of food were performed in a laboratory to characterize particles and gases. Aerosol mass spectrometer (AMS) measurements showed that the relative ionization efficiency for OA was higher (1.56-3.06) relative to a typical value of 1.4, concluding that AMS is over-estimating COA and suggesting that previous studies likely over-estimated COA concentrations. Food-cooking mass spectra were generated using AMS, and gas and particle food markers were identified with filter inlets for gases and aerosols-chemical ionization mass spectrometer (CIMS) measurements to be used in future food cooking-source apportionment studies. However, there is a considerable variability in both gas and particle markers, and dilution plays an important role in the particle mass budget, showing the importance of using these markers with caution during receptor modeling. These findings can be used to better understand the chemical composition of COA, and they provides useful information to be used in future source-apportionment studies.

LEVIS ion source and beam characterization on PBFA-II

International Nuclear Information System (INIS)

Renk, T.J.; Tisone, G.C.; Adams, R.G.; Bailey, J.E.; Filuk, A.B.; Johnson, D.J.; Pointon, T.D.

1993-01-01

We report on the continuing development of the LEVIS (Laser Evaporation Ion Source) lithium active ion source for the 15-cm radial focussing ion diode on PBFA-11. We found previously that DC-heating of the anode surface to 150 degrees C maximum for 5 hours resulted in a pure lithium beam. This paper discusses the characterization of LEVIS source uniformity by Faraday cup arrays and multiple lines of sight for visible light spectroscopy. These diagnostics give some evidence of nonuniformity in both A-K gap electric fields and ion current density. Despite this, however, the measured focal spot size appears smaller than with a passive LiF source operated in the same magnetic field topology. Experiments using a curved anode for vertical beam focussing show reduced ion beam turn-on delay by 5 ns by altering the magnetic field topology as well as anode curvature. Another 3--5 ns reduction was achieved by switching from a passive LiF to the active LEVIS source

Production and characterization of a custom-made {sup 228}Th source with reduced neutron source strength for the Borexino experiment

Energy Technology Data Exchange (ETDEWEB)

Maneschg, W., E-mail: werner.maneschg@mpi-hd.mpg.de [Max Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Baudis, L. [Physik Institut der Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Dressler, R. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Eberhardt, K. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Eichler, R. [Paul Scherrer Institut, CH-5232 Villigen (Switzerland); Keller, H. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Lackner, R. [Max Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Praast, B. [Institut fuer Kernchemie, Universitaet Mainz, Fritz-Strassmann-Weg 2, D-55128 Mainz (Germany); Santorelli, R. [Physik Institut der Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Schreiner, J. [Max Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Tarka, M. [Physik Institut der Universitaet Zuerich, Winterthurerstrasse 190, CH-8057 Zuerich (Switzerland); Wiegel, B.; Zimbal, A. [Physikalisch-Technische Bundesanstalt, Bundesallee 100, D-38116 Braunschweig (Germany)

2012-07-11

A custom-made {sup 228}Th source of several MBq activities was produced for the Borexino experiment to study the external background of the detector. The aim was to reduce the unwanted neutron emission produced via ({alpha},n) reactions in ceramics typically used for commercial {sup 228}Th sources. For this purpose a ThCl{sub 4} solution was chemically converted into ThO{sub 2} and embedded in a gold foil. The paper describes the production of the custom-made source and its characterization by means of {gamma}-activity, dose rate and neutron source strength measurements. From {gamma}-spectroscopic measurements it was deduced that activity transfer from the initial solution to the final source was >91% (at 68% C.L.) and the final activity was (5.41{+-}0.30) MBq. The dose rate was measured with two dosimeters yielding 12.1 mSv/h and 14.3 mSv/h in 1 cm distance. The neutron source strength of the 5.41 MBq {sup 228}Th source was determined to be (6.59{+-}0.85) s{sup -1}.

Characterization and packaging of disused sealed radioactive sources

International Nuclear Information System (INIS)

Aguilar, S.L.

2013-01-01

In Bolivia are generated disused sealed sources and radioactive waste resulting from the use of radioactive materials in industrial, research and medicine. The last includes the diagnosis and treatment. Whereas exposure to ionizing radiation is a potential hazard to personnel who applies it, to those who benefit from its use or for the community at large, it is necessary to control the activities in this field. The Instituto Boliviano de Ciencia y Tecnologia Nuclear - IBTEN is working on a regional project from International Atomic Energy Agency - IAEA, RLA/09/062 Project - TSA 4, Strengthening the National Infrastructure and Regulatory Framework for the Safe Management of Radioactive waste in Latin America. This Project has strengthened the regulatory framework regarding the safe management of radioactive waste. The aim of this work was focused primarily on the security aspects in the safe management of disused sealed sources. The tasks are listed below: 1. Characterization of disused sealed sources 2. Preparation for transport to temporary storage 3. Control of all disused radioactive sources. (author)

Using a tungsten rollbar to characterize the source spot of a megavoltage bremsstrahlung linac

International Nuclear Information System (INIS)

Schach von Wittenau, A.E.; Logan, C.M.; Rikard, R.

2002-01-01

In photon teletherapy, the size and functional form of the photon source spot affect both the sharpness of the penumbra of treatment fields and the sharpness of portal images. Photon source spot parameters are also used in photon teletherapy dose calculation codes. A simple method for characterizing the source spot would complement the existing, more involved methods that have been described in the medical physics literature. Such a method, using a rollbar made of tungsten or other high-Z metal, is used in industrial radiography. We describe the use of a tungsten rollbar for characterizing the source spot edge spread function (and thereby the source spot size and shape) of a megavoltage bremsstrahlung photon source. We use Monte Carlo simulations to quantify anticipated experimental artifacts of the method, assuming typical spot sizes for circ-function, Gaussian, and Bennett line shapes. We illustrate the use of the rollbar method by characterizing the source spot of a typical 9 MV linac used for industrial radiography. The source spot is analyzed using two approaches: (a) fitting the rollbar image with analytic functions and (b) using Abel inversion to obtain the cylindrically symmetric spot profile consistent with the measured rollbar image. Monte Carlo simulations, based on a 6 MV photon teletherapy accelerator, suggest that aspects of the method are applicable to medical bremsstrahlung sources

Receptor modeling studies for the characterization of PM10 pollution sources in Belgrade

Directory of Open Access Journals (Sweden)

Mijić Zoran

2012-01-01

Full Text Available The objective of this study is to determine the major sources and potential source regions of PM10 over Belgrade, Serbia. The PM10 samples were collected from July 2003 to December 2006 in very urban area of Belgrade and concentrations of Al, V, Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were analyzed by atomic absorption spectrometry. The analysis of seasonal variations of PM10 mass and some element concentrations reported relatively higher concentrations in winter, what underlined the importance of local emission sources. The Unmix model was used for source apportionment purpose and the four main source profiles (fossil fuel combustion; traffic exhaust/regional transport from industrial centers; traffic related particles/site specific sources and mineral/crustal matter were identified. Among the resolved factors the fossil fuel combustion was the highest contributor (34% followed by traffic/regional industry (26%. Conditional probability function (CPF results identified possible directions of local sources. The potential source contribution function (PSCF and concentration weighted trajectory (CWT receptor models were used to identify spatial source distribution and contribution of regional-scale transported aerosols. [Projekat Ministarstva nauke Republike Srbije, br. III43007 i br. III41011

Radiological Characterization Technical Report on Californium-252 Sealed Source Transuranic Debris Waste for the Off-Site Source Recovery Project at Los Alamos National Laboratory

Energy Technology Data Exchange (ETDEWEB)

Feldman, Alexander [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-04-24

This document describes the development and approach for the radiological characterization of Cf-252 sealed sources for shipment to the Waste Isolation Pilot Plant. The report combines information on the nuclear material content of each individual source (mass or activity and date of manufacture) with information and data on the radionuclide distributions within the originating nuclear material. This approach allows for complete and accurate characterization of the waste container without the need to take additional measurements. The radionuclide uncertainties, developed from acceptable knowledge (AK) information regarding the source material, are applied to the summed activities in the drum. The AK information used in the characterization of Cf-252 sealed sources has been qualified by the peer review process, which has been reviewed and accepted by the Environmental Protection Agency.

Characterizing the Performance of the Princeton Advanced Test Stand Ion Source

Science.gov (United States)

Stepanov, A.; Gilson, E. P.; Grisham, L.; Kaganovich, I.; Davidson, R. C.

2012-10-01

The Princeton Advanced Test Stand (PATS) is a compact experimental facility for studying the physics of intense beam-plasma interactions relevant to the Neutralized Drift Compression Experiment - II (NDCX-II). The PATS facility consists of a multicusp RF ion source mounted on a 2 m-long vacuum chamber with numerous ports for diagnostic access. Ar+ beams are extracted from the source plasma with three-electrode (accel-decel) extraction optics. The RF power and extraction voltage (30 - 100 kV) are pulsed to produce 100 μsec duration beams at 0.5 Hz with excellent shot-to-shot repeatability. Diagnostics include Faraday cups, a double-slit emittance scanner, and scintillator imaging. This work reports measurements of beam parameters for a range of beam energies (30 - 50 keV) and currents to characterize the behavior of the ion source and extraction optics. Emittance scanner data is used to calculate the beam trace-space distribution and corresponding transverse emittance. If the plasma density is changing during a beam pulse, time-resolved emittance scanner data has been taken to study the corresponding evolution of the beam trace-space distribution.

Characterization of the radon source in North-Central Florida. Final report part 1 -- Final project report; Final report part 2 -- Technical report

International Nuclear Information System (INIS)

1997-01-01

This report contains two separate parts: Characterization of the Radon Source in North-Central Florida (final report part 1 -- final project report); and Characterization of the Radon Source in North-Central Florida (technical report). The objectives were to characterize the radon 222 source in a region having a demonstrated elevated indoor radon potential and having geology, lithology, and climate that are different from those in other regions of the U.S. where radon is being studied. Radon availability and transport in this region were described. Approaches for predicting the radon potential of lands in this region were developed

Characterization of strong (241)Am sources.

Science.gov (United States)

Vesterlund, Anna; Chernikova, Dina; Cartemo, Petty; Axell, Kåre; Nordlund, Anders; Skarnemark, Gunnar; Ekberg, Christian; Ramebäck, Henrik

2015-05-01

Gamma ray spectra of strong (241)Am sources may reveal information about the source composition as there may be other radioactive nuclides such as progeny and radioactive impurities present. In this work the possibility to use gamma spectrometry to identify inherent signatures in (241)Am sources in order to differentiate sources from each other, is investigated. The studied signatures are age, i.e. time passed since last chemical separation, and presence of impurities. The spectra of some sources show a number of Doppler broadened peaks in the spectrum which indicate the presence of nuclear reactions on light elements within the sources. The results show that the investigated sources can be differentiated between by age and/or presence of impurities. These spectral features would be useful information in a national nuclear forensics library (NNFL) in cases when the visual information on the source, e.g. the source number, is unavailable. Copyright © 2015 Elsevier Ltd. All rights reserved.

Characterization of rotary-percussion drilling as a seismic-while-drilling source

Science.gov (United States)

Xiao, Yingjian; Hurich, Charles; Butt, Stephen D.

2018-04-01

This paper focuses on an evaluation of rotary-percussion drilling (RPD) as a seismic source. Two field experiments were conducted to characterize seismic sources from different rocks with different strengths, i.e. weak shale and hard arkose. Characterization of RPD sources consist of spectral analysis and mean power measurements, along with field measurements of the source radiation patterns. Spectral analysis shows that increase of rock strength increases peak frequency and widens bandwidth, which makes harder rock more viable for seismic-while-drilling purposes. Mean power analysis infers higher magnitude of body waves in RPD than in conventional drillings. Within the horizontal plane, the observed P-wave energy radiation pattern partially confirms the theoretical radiation pattern under a single vertical bit vibration. However a horizontal lobe of energy is observed close to orthogonal to the axial bit vibration. From analysis, this lobe is attributed to lateral bit vibration, which is not documented elsewhere during RPD. Within the horizontal plane, the observed radiation pattern of P-waves is generally consistent with a spherically-symmetric distribution of energy. In addition, polarization analysis is conducted on P-waves recorded at surface geophones for understanding the particle motions. P-wave particle motions are predominantly in the vertical direction showing the interference of the free-surface.

Study and characterization of a phosphorous ion source and development of a emittancemeter suited to multi-beam ion sources

International Nuclear Information System (INIS)

Hoang Gia Tuong.

1982-12-01

The ionization process which is used is the electronic bombardment. Phosphorus choice for the source experimentation is motivated by its principal destination: ionic implantation. Heavy ion applications are also quoted. Operating conditions allowing good results to be obtained are determined after a study of different parameters such as the electron current, the neutron pressure and the extraction voltage: the ion current obtained is of the order of mA. The source emittance, representing the quality of the ionic beam, is measured by a method suited to multibeam sources [fr

Pressure monitoring and characterization of external sources of contamination at the site of the payment drinking water epidemiological studies.

Science.gov (United States)

Besner, Marie-Claude; Broséus, Romain; Lavoie, Jean; Giovanni, George Di; Payment, Pierre; Prévost, Michèle

2010-01-01

The 1990s epidemiological studies by Payment and colleagues suggested that an increase in gastrointestinal illnesses observed in the population consuming tap water from a system meeting all water quality regulations might be associated with distribution system deficiencies. In the current study, the vulnerability of this distribution system to microbial intrusion was assessed by characterizing potential sources of contamination near pipelines and monitoring the frequency and magnitude of negative pressures. Bacterial indicators of fecal contamination were recovered more frequently in the water from flooded air-valve vaults than in the soil or water from pipe trenches. The level of fecal contamination in these various sources was more similar to levels from river water rather than wastewater. Because of its configuration, this distribution system is vulnerable to negative pressures when pressure values out of the treatment plant reach or drop below 172 kPa (25 psi), which occurred nine times during a monitoring period of 17 months. The results from this investigation suggest that this distribution system is vulnerable to contamination by intrusion. Comparison of the frequency of occurrence of negative pressure events and repair rates with data from other distribution systems suggests that the system studied by Payment and colleagues is not atypical.

Characterization of urban aerosol sources in Debrecen, Hungary

International Nuclear Information System (INIS)

Kertesz, Zs.; Szoboszlai, T.; Angyal, A.; Dobos, E.; Borbely-Kiss, I.

2009-01-01

Complete text of publication follows. Aerosol pollution represents significant health hazard in urban environments. Despite the fact that Debrecen has not a much stressed environment the city is highly exposed to aerosol pollution. In order to evaluate the impact of aerosol particles on health, the knowledge of the particle size distribution, chemical composition, sources, and their change in time and space is needed. This work presents a source apportionment study of fine (particles with aerodynamic diameter less than 2.5 μm) and coarse (particles with aerodynamic diameter between 2.5 and 10 μm) particulate matter in Debrecen by following the evolution of the elemental components with hourly time resolution. The variation of the elemental concentrations, their periodicity, correlation with other elements and meteorological parameters were studied on samples collected in different seasons. Aerosol sources were determined using the positive matrix factorization (PMF) method. Aerosol samples were collected in the garden of the ATOMKI with a 2-stage sequential streaker sampler manufactured by PIXE International, which collected the fine and coarse fraction separately with few hours' time resolution. Between October 2007 and January 2009 five 10-days long sampling campaigns were carried out. The elemental composition was determined by Particle Induced X-ray emission (PIXE) for Z ≥ 13, and the elemental carbon (BC) content was estimated with a smoke stain reflectometer. Source apportionment was carried out with the PMF receptor model developed for aerosol source characterization, provided by US EPA. Mass of species apportioned to factor, percentage of species apportioned to factors and average factor contributions of the campaigns, of working days and weekends and within the days were calculated. The PMF analysis resulted seven factors in the fine and seven factors in the coarse mode. The main sources of atmospheric aerosol in the city of Debrecen were traffic

Methodology and main results of seismic source characterization for the PEGASOS Project, Switzerland

International Nuclear Information System (INIS)

Coppersmith, K. J.; Youngs, R. R.; Sprecher, Ch.

2009-01-01

Under the direction of the National Cooperative for the Disposal of Radioactive Waste (NAGRA), a probabilistic seismic hazard analysis was conducted for the Swiss nuclear power plant sites. The study has become known under the name 'PEGASOS Project'. This is the first of a group of papers in this volume that describes the seismic source characterization methodology and the main results of the project. A formal expert elicitation process was used, including dissemination of a comprehensive database, multiple workshops for identification and discussion of alternative models and interpretations, elicitation interviews, feedback to provide the experts with the implications of their preliminary assessments, and full documentation of the assessments. A number of innovative approaches to the seismic source characterization methodology were developed by four expert groups and implemented in the study. The identification of epistemic uncertainties and treatment using logic trees were important elements of the assessments. Relative to the assessment of the seismotectonic framework, the four expert teams identified similar main seismotectonic elements: the Rhine Graben, the Jura / Molasse regions, Helvetic and crystalline subdivisions of the Alps, and the southern Germany region. In defining seismic sources, the expert teams used a variety of approaches. These range from large regional source zones having spatially-smoothed seismicity to smaller local zones, to account for spatial variations in observed seismicity. All of the teams discussed the issue of identification of feature-specific seismic sources (i.e. individual mapped faults) as well as the potential reactivation of the boundary faults of the Permo-Carboniferous grabens. Other important seismic source definition elements are the specification of earthquake rupture dimensions and the earthquake depth distribution. Maximum earthquake magnitudes were assessed for each seismic source using approaches that consider the

Characterization of the radiation background at the Spallation Neutron Source

International Nuclear Information System (INIS)

DiJulio, Douglas D.; Cherkashyna, Nataliia; Scherzinger, Julius; Khaplanov, Anton; Pfeiffer, Dorothea; Cooper-Jensen, Carsten P.; Fissum, Kevin G.; Kanaki, Kalliopi; Kirstein, Oliver; Hall-Wilton, Richard J.; Bentley, Phillip M.; Ehlers, Georg; Gallmeier, Franz X.; Hornbach, Donald E.; Iverson, Erik B.; Newby, Robert J.

2016-01-01

We present a survey of the radiation background at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory, TN, USA during routine daily operation. A broad range of detectors was used to characterize primarily the neutron and photon fields throughout the facility. These include a WENDI-2 extended range dosimeter, a thermoscientific NRD, an Arktis 4 He detector, and a standard NaI photon detector. The information gathered from the detectors was used to map out the neutron dose rates throughout the facility and also the neutron dose rate and flux profiles of several different beamlines. The survey provides detailed information useful for developing future shielding concepts at spallation neutron sources, such as the European Spallation Source (ESS), currently under construction in Lund, Sweden. (paper)

Central and Eastern United States (CEUS) Seismic Source Characterization (SSC) for Nuclear Facilities

International Nuclear Information System (INIS)

Coppersmith, Kevin J.; Salomone, Lawrence A.; Fuller, Chris W.; Glaser, Laura L.; Hanson, Kathryn L.; Hartleb, Ross D.; Lettis, William R.; Lindvall, Scott C.; McDuffie, Stephen M.; McGuire, Robin K.; Stirewalt, Gerry L.; Toro, Gabriel R.; Youngs, Robert R.; Slayter, David L.; Bozkurt, Serkan B.; Cumbest, Randolph J.; Falero, Valentina Montaldo; Perman, Roseanne C.; Shumway, Allison M.; Syms, Frank H.; Tuttle, Martitia P.

2012-01-01

Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts. The model will be used to assess the present-day composite distribution for seismic sources along with their characterization in the CEUS and uncertainty. In addition, this model is in a form suitable for use in PSHA evaluations for regulatory activities, such as Early Site Permit (ESPs) and Combined Operating License Applications (COLAs). Applications, Values, and Use Development of a regional CEUS seismic source model will provide value to those who (1) have submitted an ESP or COLA for Nuclear Regulatory Commission (NRC) review before 2011; (2) will submit an ESP or COLA for NRC review after 2011; (3) must respond to safety issues resulting from NRC Generic Issue 199 (GI-199) for existing plants and (4) will prepare PSHAs to meet design and periodic review requirements for current and future nuclear facilities. This work replaces a previous study performed approximately 25 years ago. Since that study was completed, substantial work has been done to improve the understanding of seismic sources and their characterization in the CEUS. Thus, a new regional SSC model provides a consistent, stable basis for computing PSHA for a future time span. Use of a new SSC model reduces the risk of delays in new plant licensing due to more conservative interpretations in the existing and future literature. Perspective The purpose of this study, jointly sponsored by EPRI, the U.S. Department of Energy (DOE), and the NRC was to develop a new CEUS SSC model. The team assembled to accomplish this purpose was composed of distinguished subject matter experts from industry, government, and academia. The resulting model is unique, and because this project has solicited input from the present-day larger technical community, it is not likely that there will be a need for significant revision for a number of years. See also Sponsors Perspective for more details. The goal of this project was to implement the CEUS SSC work plan

Laser-ablation-based ion source characterization and manipulation for laser-driven ion acceleration

Science.gov (United States)

Sommer, P.; Metzkes-Ng, J.; Brack, F.-E.; Cowan, T. E.; Kraft, S. D.; Obst, L.; Rehwald, M.; Schlenvoigt, H.-P.; Schramm, U.; Zeil, K.

2018-05-01

For laser-driven ion acceleration from thin foils (∼10 μm–100 nm) in the target normal sheath acceleration regime, the hydro-carbon contaminant layer at the target surface generally serves as the ion source and hence determines the accelerated ion species, i.e. mainly protons, carbon and oxygen ions. The specific characteristics of the source layer—thickness and relevant lateral extent—as well as its manipulation have both been investigated since the first experiments on laser-driven ion acceleration using a variety of techniques from direct source imaging to knife-edge or mesh imaging. In this publication, we present an experimental study in which laser ablation in two fluence regimes (low: F ∼ 0.6 J cm‑2, high: F ∼ 4 J cm‑2) was applied to characterize and manipulate the hydro-carbon source layer. The high-fluence ablation in combination with a timed laser pulse for particle acceleration allowed for an estimation of the relevant source layer thickness for proton acceleration. Moreover, from these data and independently from the low-fluence regime, the lateral extent of the ion source layer became accessible.

Characterization of dynamic changes of current source localization based on spatiotemporal fMRI constrained EEG source imaging

Science.gov (United States)

Nguyen, Thinh; Potter, Thomas; Grossman, Robert; Zhang, Yingchun

2018-06-01

Objective. Neuroimaging has been employed as a promising approach to advance our understanding of brain networks in both basic and clinical neuroscience. Electroencephalography (EEG) and functional magnetic resonance imaging (fMRI) represent two neuroimaging modalities with complementary features; EEG has high temporal resolution and low spatial resolution while fMRI has high spatial resolution and low temporal resolution. Multimodal EEG inverse methods have attempted to capitalize on these properties but have been subjected to localization error. The dynamic brain transition network (DBTN) approach, a spatiotemporal fMRI constrained EEG source imaging method, has recently been developed to address these issues by solving the EEG inverse problem in a Bayesian framework, utilizing fMRI priors in a spatial and temporal variant manner. This paper presents a computer simulation study to provide a detailed characterization of the spatial and temporal accuracy of the DBTN method. Approach. Synthetic EEG data were generated in a series of computer simulations, designed to represent realistic and complex brain activity at superficial and deep sources with highly dynamical activity time-courses. The source reconstruction performance of the DBTN method was tested against the fMRI-constrained minimum norm estimates algorithm (fMRIMNE). The performances of the two inverse methods were evaluated both in terms of spatial and temporal accuracy. Main results. In comparison with the commonly used fMRIMNE method, results showed that the DBTN method produces results with increased spatial and temporal accuracy. The DBTN method also demonstrated the capability to reduce crosstalk in the reconstructed cortical time-course(s) induced by neighboring regions, mitigate depth bias and improve overall localization accuracy. Significance. The improved spatiotemporal accuracy of the reconstruction allows for an improved characterization of complex neural activity. This improvement can be

Surface, interface and bulk materials characterization using Indus synchrotron sources

International Nuclear Information System (INIS)

Phase, Deodatta M.

2014-01-01

Synchrotron radiation sources, providing intense, polarized and stable beams of ultra violet, soft and hard x-ray photons, are having great impact on physics, chemistry, biology, materials science and other areas research. In particular synchrotron radiation has revolutionized materials characterization techniques by enhancing its capabilities for investigating the structural, electronic and magnetic properties of solids. The availability of synchrotron sources and necessary instrumentation has led to considerable improvements in spectral resolution and intensities. As a result, application scope of different materials characterization techniques has tremendously increased particularly in the analysis of solid surfaces, interfaces and bulk materials. The Indian synchrotron storage ring, Indus-1 and Indus-2 are in operation at RRCAT, Indore. The UGC-DAE CSR with the help of university scientist had designed and developed an angle integrated photoelectron spectroscopy (AlPES) beam line on Indus-1 storage ring of 450 MeV and polarized light beam line for soft x-ray absorption spectroscopy (SXAS) on Indus-2 storage ring of 2.5 GeV. (author)

Characterization of a alpha particle detector CR-39 exposed to a source of radium

International Nuclear Information System (INIS)

Maino, Leandro Marcondes

2009-01-01

In this project, the main goal is the characterization of a alpha particle detector CR-39 exposed to a source of radio. Three detectors were exposed to a source of radium and then chemically treated for different periods. This way, we could analyze these samples and collect the information needed to verify that at least one of the chemical attack, there has been a separation of the energies alpha particles incident with distinct peaks, thus characterizing the CR-39 as alpha spectrometer in the range 2.5 to 6.3 MeV . (author)

Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

Directory of Open Access Journals (Sweden)

Sergi Abad

2015-12-01

Full Text Available Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1, biomass (0.7–0.8 g cells/g Substrate and product (0.14–0.15 g DHA/g cells yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct.

Characterizing the oxygen isotopic composition of phosphate sources to aquatic ecosystems

Science.gov (United States)

Young, M.B.; McLaughlin, K.; Kendall, C.; Stringfellow, W.; Rollog, M.; Elsbury, K.; Donald, E.; Paytan, A.

2009-01-01

The oxygen isotopic composition of dissolved inorganic phosphate (δ18Op) in many aquatic ecosystems is not in isotopic equilibrium with ambient water and, therefore, may reflect the source δ18Op. Identification of phosphate sources to water bodies is critical for designing best management practices for phosphate load reduction to control eutrophication. In order for δ18O p to be a useful tool for source tracking, the δ18Op of phosphate sources must be distinguishable from one another; however, the δ18Op of potential sources has not been well characterized. We measured the δ18O p of a variety of known phosphate sources, including fertilizers, semiprocessed phosphorite ore, particulate aerosols, detergents, leachates of vegetation, soil, animal feces, and wastewater treatment plant effluent. We found a considerable range of δ18Op values (from +8.4 to +24.9‰) for the various sources, and statistically significant differences were found between several of the source types. δ18Op measured in three different fresh water systems was generally not in equilibrium with ambient water. Although there is overlap in δ18Op values among the groups of samples, our results indicate that some sources are isotopically distinct and δ18Op can be used for identifying phosphate sources to aquatic systems.

Pseudodynamic Source Characterization for Strike-Slip Faulting Including Stress Heterogeneity and Super-Shear Ruptures

KAUST Repository

Mena, B.

2012-08-08

Reliable ground‐motion prediction for future earthquakes depends on the ability to simulate realistic earthquake source models. Though dynamic rupture calculations have recently become more popular, they are still computationally demanding. An alternative is to invoke the framework of pseudodynamic (PD) source characterizations that use simple relationships between kinematic and dynamic source parameters to build physically self‐consistent kinematic models. Based on the PD approach of Guatteri et al. (2004), we propose new relationships for PD models for moderate‐to‐large strike‐slip earthquakes that include local supershear rupture speed due to stress heterogeneities. We conduct dynamic rupture simulations using stochastic initial stress distributions to generate a suite of source models in the magnitude Mw 6–8. This set of models shows that local supershear rupture speed prevails for all earthquake sizes, and that the local rise‐time distribution is not controlled by the overall fault geometry, but rather by local stress changes on the faults. Based on these findings, we derive a new set of relations for the proposed PD source characterization that accounts for earthquake size, buried and surface ruptures, and includes local rise‐time variations and supershear rupture speed. By applying the proposed PD source characterization to several well‐recorded past earthquakes, we verify that significant improvements in fitting synthetic ground motion to observed ones is achieved when comparing our new approach with the model of Guatteri et al. (2004). The proposed PD methodology can be implemented into ground‐motion simulation tools for more physically reliable prediction of shaking in future earthquakes.

Integrated spatiotemporal characterization of dust sources and outbreaks in Central and East Asia

Science.gov (United States)

Darmenova, Kremena T.

The potential of atmospheric dust aerosols to modify the Earth's environment and climate has been recognized for some time. However, predicting the diverse impact of dust has several significant challenges. One is to quantify the complex spatial and temporal variability of dust burden in the atmosphere. Another is to quantify the fraction of dust originating from human-made sources. This thesis focuses on the spatiotemporal characterization of sources and dust outbreaks in Central and East Asia by integrating ground-based data, satellite multisensor observations, and modeling. A new regional dust modeling system capable of operating over a span of scales was developed. The modeling system consists of a dust module DuMo, which incorporates several dust emission schemes of different complexity, and the PSU/NCAR mesoscale model MM5, which offers a variety of physical parameterizations and flexible nesting capability. The modeling system was used to perform for the first time a comprehensive study of the timing, duration, and intensity of individual dust events in Central and East Asia. Determining the uncertainties caused by the choice of model physics, especially the boundary layer parameterization, and the dust production scheme was the focus of our study. Implications to assessments of the anthropogenic dust fraction in these regions were also addressed. Focusing on Spring 2001, an analysis of routine surface meteorological observations and satellite multi-sensor data was carried out in conjunction with modeling to determine the extent to which integrated data set can be used to characterize the spatiotemporal distribution of dust plumes at a range of temporal scales, addressing the active dust sources in China and Mongolia, mid-range transport and trans-Pacific, long-range transport of dust outbreaks on a case-by-case basis. This work demonstrates that adequate and consistent characterization of individual dust events is central to establishing a reliable

Characterization and optimization of laser-driven electron and photon sources in keV and MeV energy ranges

International Nuclear Information System (INIS)

Bonnet, Thomas

2013-01-01

This work takes place in the framework of the characterization and the optimization of laser-driven electron and photon sources. With the goal of using these sources for nuclear physics experiments, we focused on 2 energy ranges: one around a few MeV and the other around a few tens of keV. The first part of this work is thus dedicated to the study of detectors routinely used for the characterization of laser-driven particle sources: Imaging Plates. A model has been developed and is fitted to experimental data. Response functions to electrons, photons, protons and alpha particles are established for SR, MS and TR Fuji Imaging Plates for energies ranging from a few keV to several MeV. The second part of this work present a study of ultrashort and intense electron and photon sources produced in the interaction of a laser with a solid or liquid target. An experiment was conducted at the ELFIE facility at LULI where beams of electrons and photons were accelerated up to several MeV. Energy and angular distributions of the electron and photons beams were characterized. The sources were optimized by varying the spatial extension of the plasma at both the front and the back end of the initial target position. In the optimal configuration of the laser-plasma coupling, more than 1011 electrons were accelerated. In the case of liquid target, a photon source was produced at a high repetition rate on an energy range of tens of keV by the interaction of the AURORE Laser at CELIA (10 16 W.cm -2 ) and a melted gallium target. It was shown that both the mean energy and the photon number can be increased by creating gallium jets at the surface of the liquid target with a pre-pulse. A physical interpretation supported by numerical simulations is proposed. (author)

Novel techniques for characterization of hydrocarbon emission sources in the Barnett Shale

Science.gov (United States)

Nathan, Brian Joseph

Changes in ambient atmospheric hydrocarbon concentrations can have both short-term and long-term effects on the atmosphere and on human health. Thus, accurate characterization of emissions sources is critically important. The recent boom in shale gas production has led to an increase in hydrocarbon emissions from associated processes, though the exact extent is uncertain. As an original quantification technique, a model airplane equipped with a specially-designed, open-path methane sensor was flown multiple times over a natural gas compressor station in the Barnett Shale in October 2013. A linear optimization was introduced to a standard Gaussian plume model in an effort to determine the most probable emission rate coming from the station. This is shown to be a suitable approach given an ideal source with a single, central plume. Separately, an analysis was performed to characterize the nonmethane hydrocarbons in the Barnett during the same period. Starting with ambient hourly concentration measurements of forty-six hydrocarbon species, Lagrangian air parcel trajectories were implemented in a meteorological model to extend the resolution of these measurements and achieve domain-fillings of the region for the period of interest. A self-organizing map (a type of unsupervised classification) was then utilized to reduce the dimensionality of the total multivariate set of grids into characteristic one-dimensional signatures. By also introducing a self-organizing map classification of the contemporary wind measurements, the spatial hydrocarbon characterizations are analyzed for periods with similar wind conditions. The accuracy of the classification is verified through assessment of observed spatial mixing ratio enhancements of key species, through site-comparisons with a related long-term study, and through a random forest analysis (an ensemble learning method of supervised classification) to determine the most important species for defining key classes. The hydrocarbon

Characterization of the plasma-switch interaction in the LBL HIF ion source

International Nuclear Information System (INIS)

Hewett, D.W.; Rutkowski, H.L.

1990-01-01

A new way to characterize the performance of the LBL HIF ion source has been found. In the LBL source, ions are drawn from an arc-generated plasma reservoir in which the electrons are confined by a negative-biased ''switch'' mesh. Stagnation of the plasma is prevented by absorption of the excess ion flow on this mesh. The ion beam is generated by an external negative voltage that provides Child-Langmuir extraction of the ions through the switch mesh. We elucidate the physics requirements of the source and deduce switch mesh parameters needed for successful operation. 2 refs., 2 figs

Initial source and site characterization studies for the U.C. Santa Barbara campus

Energy Technology Data Exchange (ETDEWEB)

Archuleta, R.; Nicholson, C.; Steidl, J.; Gurrola, L.; Alex, C.; Cochran, E.; Ely, G.; Tyler, T. [University of California, Santa Barbara (United States)

1997-12-01

The University of California Campus-Laboratory Collaboration (CLC) project is an integrated 3 year effort involving Lawrence Livermore National Laboratory (LLNL) and four UC campuses - Los Angeles (UCLA), Riverside (UCR), Santa Barbara (UCSB), and San Diego (UCSD) - plus additional collaborators at San Diego State University (SDSU), at Los Alamos National Laboratory and in industry. The primary purpose of the project is to estimate potential ground motions from large earthquakes and to predict site-specific ground motions for one critical structure on each campus. This project thus combines the disciplines of geology, seismology, geodesy, soil dynamics, and earthquake engineering into a fully integrated approach. Once completed, the CLC project will provide a template to evaluate other buildings at each of the four UC campuses, as well as provide a methodology for evaluating seismic hazards at other critical sites in California, including other UC locations at risk from large earthquakes. Another important objective of the CLC project is the education of students and other professional in the application of this integrated, multidisciplinary, state-of-the-art approach to the assessment of earthquake hazard. For each campus targeted by the CLC project, the seismic hazard study will consist of four phases: Phase I - Initial source and site characterization, Phase II - Drilling, logging, seismic monitoring, and laboratory dynamic soil testing, Phase III - Modeling of predicted site-specific earthquake ground motions, and Phase IV - Calculations of 3D building response. This report cover Phase I for the UCSB campus and incudes results up through March 1997.

Central and Eastern United States (CEUS) Seismic Source Characterization (SSC) for Nuclear Facilities Project

Energy Technology Data Exchange (ETDEWEB)

Kevin J. Coppersmith; Lawrence A. Salomone; Chris W. Fuller; Laura L. Glaser; Kathryn L. Hanson; Ross D. Hartleb; William R. Lettis; Scott C. Lindvall; Stephen M. McDuffie; Robin K. McGuire; Gerry L. Stirewalt; Gabriel R. Toro; Robert R. Youngs; David L. Slayter; Serkan B. Bozkurt; Randolph J. Cumbest; Valentina Montaldo Falero; Roseanne C. Perman' Allison M. Shumway; Frank H. Syms; Martitia (Tish) P. Tuttle

2012-01-31

Seismic Hazard Analysis: Guidance on Uncertainty and Use of Experts. The model will be used to assess the present-day composite distribution for seismic sources along with their characterization in the CEUS and uncertainty. In addition, this model is in a form suitable for use in PSHA evaluations for regulatory activities, such as Early Site Permit (ESPs) and Combined Operating License Applications (COLAs). Applications, Values, and Use Development of a regional CEUS seismic source model will provide value to those who (1) have submitted an ESP or COLA for Nuclear Regulatory Commission (NRC) review before 2011; (2) will submit an ESP or COLA for NRC review after 2011; (3) must respond to safety issues resulting from NRC Generic Issue 199 (GI-199) for existing plants and (4) will prepare PSHAs to meet design and periodic review requirements for current and future nuclear facilities. This work replaces a previous study performed approximately 25 years ago. Since that study was completed, substantial work has been done to improve the understanding of seismic sources and their characterization in the CEUS. Thus, a new regional SSC model provides a consistent, stable basis for computing PSHA for a future time span. Use of a new SSC model reduces the risk of delays in new plant licensing due to more conservative interpretations in the existing and future literature. Perspective The purpose of this study, jointly sponsored by EPRI, the U.S. Department of Energy (DOE), and the NRC was to develop a new CEUS SSC model. The team assembled to accomplish this purpose was composed of distinguished subject matter experts from industry, government, and academia. The resulting model is unique, and because this project has solicited input from the present-day larger technical community, it is not likely that there will be a need for significant revision for a number of years. See also Sponsors Perspective for more details. The goal of this project was to implement the CEUS SSC work plan

Monte Carlo dose characterization of a new 90Sr/90Y source with balloon for intravascular brachytherapy

International Nuclear Information System (INIS)

Wang Ruqing; Li, X. Allen; Lobdell, John

2003-01-01

Beta emitting source wires or seeds have been adopted in clinical practice of intravascular brachytherapy for coronary vessels. Due to the limitation of penetration depth, this type of source is normally not applicable to treat vessels with large diameter, e.g., peripheral vessel. In the effort to extend application of its beta source for peripheral vessels, Novoste has recently developed a new catheter-based system, the Corona trade mark sign 90 Sr/ 90 Y system. It is a source train of 6 cm length and is jacketed by a balloon. The existence of the balloon increases the penetration of the beta particles and maintains the source within a location away from the vessel wall. Using the EGSnrc Monte Carlo system, we have calculated the two-dimensional (2-D) dose rate distribution of the Corona trade mark sign system in water for a balloon diameter of 5 mm. The dose rates on the transverse axis obtained in this study are in good agreement with calibration results of the National Institute of Standards and Technology for the same system for balloon diameters of 5 and 8 mm. Features of the 2-D dose field were studied in detail. The dose parameters based on AAPM TG-60 protocol were derived. For a balloon diameter of 5 mm, the dose rate at the reference point (defined as r 0 =4.5 mm, 2 mm from the balloon surface) is found to be 0.010 28 Gy min -1 mCi -1 . A new formalism for a better characterization of this long source is presented. Calculations were also performed for other balloon diameters. The dosimetry for this source is compared with a 192 Ir source, commonly used for peripheral arteries. In conclusion, we have performed a detailed dosimetric characterization for a new beta source for peripheral vessels. Our study shows that, from dosimetric point of view, the Corona trade mark sign system can be used for the treatment of an artery with a large diameter, e.g., peripheral vessel

Characterizing the source of radon indoors

International Nuclear Information System (INIS)

Nero, A.V.; Nazaroff, W.W.

1983-09-01

Average indoor radon concentrations range over more than two orders of magnitude, largely because of variability in the rate at which radon enters from building materials, soil, and water supplies. Determining the indoor source magnitude requires knowledge of the generation of radon in source materials, its movement within materials by diffusion and convection, and the means of its entry into buildings. This paper reviews the state of understanding of indoor radon sources and transport. Our understanding of generation rates in and movement through building materials is relatively complete and indicates that, except for materials with unusually high radionuclide contents, these sources can account for observed indoor radon concentrations only at the low end of the range observed. Our understanding of how radon enters buildings from surrounding soil is poorer, however recent experimental and theoretical studies suggest that soil may be the predominant source in many cases where the indoor radon concentration is high. 73 references, 3 figures, 1 table

Characterization of radioactive orphan sources by gamma spectrometry; Caracterizacion de fuentes huerfanas radiactivas por espectrometria gamma

Energy Technology Data Exchange (ETDEWEB)

Cruz W, H., E-mail: wcruz@ipen.gob.pe [Instituto Peruano de Energia Nuclear (PGRR/IPEN), Lima (Peru). Planta de Gestion de Residuos Radiactivos

2013-07-01

The sealed radioactive sources are widely applicable in industry. They must have a permanent control and must be registered with the Technical Office of the National Authority (OTAN). However, at times it has identified the presence of abandoned sealed sources unknown to the owner. These sources are called 'orphan sources'. Of course these sources represent a high potential risk because accidents can trigger dire consequences depending on your activity and chemical form in which it presents the radioisotope. This paper describes the process and the actions taken to characterize two orphan radioactive sources from the smelter a Aceros Arequipa. For characterization we used a gamma spectrometry system using a detector NaI(Tl) 3″ x 3″ with a multichannel analyzer Nucleus PCA-II. The radioisotope identified was cesium - 137 ({sup 137}Cs) in both cases. Fortunately, the sources maintained their integrity would otherwise have generated significant pollution considering the chemical form of the radioisotope and easy dispersion. (author)

Molecular characterization of bacteriophages for microbial source tracking in Korea.

Science.gov (United States)

Lee, Jung Eun; Lim, Mi Young; Kim, Sei Yoon; Lee, Sunghee; Lee, Heetae; Oh, Hyun-Myung; Hur, Hor-Gil; Ko, Gwangpyo

2009-11-01

We investigated coliphages from various fecal sources, including humans and animals, for microbial source tracking in South Korea. Both somatic and F+-specific coliphages were isolated from 43 fecal samples from farms, wild animal habitats, and human wastewater plants. Somatic coliphages were more prevalent and abundant than F+ coliphages in all of the tested fecal samples. We further characterized 311 F+ coliphage isolates using RNase sensitivity assays, PCR and reverse transcription-PCR, and nucleic acid sequencing. Phylogenetic analyses were performed based on the partial nucleic acid sequences of 311 F+ coliphages from various sources. F+ RNA coliphages were most prevalent among geese (95%) and were least prevalent in cows (5%). Among the genogroups of F+ RNA coliphages, most F+ coliphages isolated from animal fecal sources belonged to either group I or group IV, and most from human wastewater sources were in group II or III. Some of the group I coliphages were present in both human and animal source samples. F+ RNA coliphages isolated from various sources were divided into two main clusters. All F+ RNA coliphages isolated from human wastewater were grouped with Qbeta-like phages, while phages isolated from most animal sources were grouped with MS2-like phages. UniFrac significance statistical analyses revealed significant differences between human and animal bacteriophages. In the principal coordinate analysis (PCoA), F+ RNA coliphages isolated from human waste were distinctively separate from those isolated from other animal sources. However, F+ DNA coliphages were not significantly different or separate in the PCoA. These results demonstrate that proper analysis of F+ RNA coliphages can effectively distinguish fecal sources.

Characterization of HDR Ir-192 source for 3D planning system

International Nuclear Information System (INIS)

Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D.; Rubo, Rodrigo; Ferreira, Louise A.

2011-01-01

Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

Characterization of HDR Ir-192 source for 3D planning system

Energy Technology Data Exchange (ETDEWEB)

Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D., E-mail: gabriel.fonseca@usp.b, E-mail: hyoriyaz@ipen.b, E-mail: ptsiquei@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rubo, Rodrigo [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia; Minamisawa, Renato A., E-mail: renato.minamisawa@psi.c [Paul Scherrer Institut (PSI), Villigen (Switzerland); Ferreira, Louise A. [Universidade Estadual de Maringa (UEM), PR (Brazil). Fac. de Medicina

2011-07-01

Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

Mass spectrometric characterization of a pyrolytic radical source using femtosecond ionization

Energy Technology Data Exchange (ETDEWEB)

Frey, H M; Beaud, P; Mischler, B; Radi, P P; Tzannis, A P; Gerber, T [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-06-01

Radicals play, as reactive species, an important role in the chemistry of combustion. In contrast to atmospheric flames where spectra are congested due to high vibrational and rotational excitation, experiments in the cold environment of a molecular beam (MB) yield clean spectra that can be easily attributed to one species by Resonantly Enhanced Multi Photon Ionization (REMP). A pyrolytic radical source has been set up. To characterize the efficiency of the source `soft` ionization with femto second pulses is applied which results in less fragmentation, simplifying the interpretation of the mass spectrum. (author) figs., tabs., refs.

Characterization of γ-ray background at IMAT beamline of ISIS Spallation Neutron Source

Science.gov (United States)

Festa, G.; Andreani, C.; Arcidiacono, L.; Burca, G.; Kockelmann, W.; Minniti, T.; Senesi, R.

2017-08-01

The environmental γ -ray background on the IMAT beamline at ISIS Spallation Neutron Source, Target Station 2, is characterized via γ spectroscopy. The measurements include gamma exposure at the imaging detector position, along with the gamma background inside the beamline. Present results are discussed and compared with previous measurements recorded at INES and VESUVIO beamlines operating at Target Station 1. They provide new outcome for expanding and optimizing the PGAA experimental capability at the ISIS neutron source for the investigation of materials, engineering components and cultural heritage objects at the ISIS neutron source.

Characterization of γ-ray background at IMAT beamline of ISIS Spallation Neutron Source

International Nuclear Information System (INIS)

Festa, G.; Andreani, C.; Arcidiacono, L.; Senesi, R.; Burca, G.; Kockelmann, W.; Minniti, T.

2017-01-01

The environmental γ -ray background on the IMAT beamline at ISIS Spallation Neutron Source, Target Station 2, is characterized via γ  spectroscopy. The measurements include gamma exposure at the imaging detector position, along with the gamma background inside the beamline. Present results are discussed and compared with previous measurements recorded at INES and VESUVIO beamlines operating at Target Station 1. They provide new outcome for expanding and optimizing the PGAA experimental capability at the ISIS neutron source for the investigation of materials, engineering components and cultural heritage objects at the ISIS neutron source.

Correlated Sources in Distributed Networks--Data Transmission, Common Information Characterization and Inferencing

Science.gov (United States)

Liu, Wei

2011-01-01

Correlation is often present among observations in a distributed system. This thesis deals with various design issues when correlated data are observed at distributed terminals, including: communicating correlated sources over interference channels, characterizing the common information among dependent random variables, and testing the presence of…

Determination of Key Risk Supervision Areas around River-Type Water Sources Affected by Multiple Risk Sources: A Case Study of Water Sources along the Yangtze’s Nanjing Section

Directory of Open Access Journals (Sweden)

Qi Zhou

2017-02-01

Full Text Available To provide a reference for risk management of water sources, this study screens the key risk supervision areas around river-type water sources (hereinafter referred to as the water sources threatened by multiple fixed risk sources (the risk sources, and establishes a comprehensive methodological system. Specifically, it comprises: (1 method of partitioning risk source concentrated sub-regions for screening water source perimeter key risk supervision areas; (2 approach of determining sub-regional risk indexes (SrRI, which characterizes the scale of sub-regional risks considering factors like risk distribution intensity within sub-regions, risk indexes of risk sources (RIRS, characterizing the risk scale of risk sources and the number of risk sources; and (3 method of calculating sub-region’s risk threats to the water sources (SrTWS which considers the positional relationship between water sources and sub-regions as well as SrRI, and the criteria for determining key supervision sub-regions. Favorable effects are achieved by applying this methodological system in determining water source perimeter sub-regions distributed along the Yangtze’s Nanjing section. Results revealed that for water sources, the key sub-regions needing supervision were SD16, SD06, SD21, SD26, SD15, SD03, SD02, SD32, SD10, SD11, SD14, SD05, SD27, etc., in the order of criticality. The sub-region with the greatest risk threats on the water sources was SD16, which was located in the middle reaches of Yangtze River. In general, sub-regions along the upper Yangtze reaches had greater threats to water sources than the lower reach sub-regions other than SD26 and SD21. Upstream water sources were less subject to the threats of sub-regions than the downstream sources other than NJ09B and NJ03.

Chemical and isotopic methods for characterization of pollutant sources in rain water

International Nuclear Information System (INIS)

Verma, M.P.

1996-01-01

The acid rain formation is related with industrial pollution. An isotopic and chemical study of the spatial and temporary distribution of the acidity in the rain gives information about the acidity source. The predominant species in the acid rain are nitrates and sulfates. For the rain monitoring is required the determination of the anion species such as HCO 3 , Cl, SO 4 , NO 3 and p H. So it was analyzed the cations Na + , K + , Ca 2+ and Mg 2+ to determine the quality analysis. All of them species can be determined with enough accuracy, except HCO 3 by modern equipment such as, liquid chromatograph, atomic absorption, etc. The HCO 3 concentration is determined by traditional methods like acid-base titration. This work presents the fundamental concepts of the titration method for samples with low alkalinity (carbonic species), for rain water. There is presented a general overview over the isotopic methods for the characterization of the origin of pollutant sources in the rain. (Author)

Characterization of DNAPL Source Zone Architecture and Prediction of Associated Plume Response: Progress and Perspectives

Science.gov (United States)

Abriola, L. M.; Pennell, K. D.; Ramsburg, C. A.; Miller, E. L.; Christ, J.; Capiro, N. L.; Mendoza-Sanchez, I.; Boroumand, A.; Ervin, R. E.; Walker, D. I.; Zhang, H.

2012-12-01

It is now widely recognized that the distribution of contaminant mass will control both the evolution of aqueous phase plumes and the effectiveness of many source zone remediation technologies at sites contaminated by dense nonaqueous phase liquids (DNAPLs). Advances in the management of sites containing DNAPL source zones, however, are currently hampered by the difficulty associated with characterizing subsurface DNAPL 'architecture'. This presentation provides an overview of recent research, integrating experimental and mathematical modeling studies, designed to improve our ability to characterize DNAPL distributions and predict associated plume response. Here emphasis is placed on estimation of the most information-rich DNAPL architecture metrics, through a combination of localized in situ tests and more readily available plume transect concentration observations. Estimated metrics will then serve as inputs to an upscaled screening model for prediction of long term plume response. Machine learning techniques were developed and refined to identify a variety of source zone metrics and associated confidence intervals through the processing of down gradient concentration data. Estimated metrics include the volumes and volume percentages of DNAPL in pools and ganglia, as well as their ratio (pool fraction). Multiphase flow and transport simulations provided training data for model development and assessment that are representative of field-scale DNAPL source zones and their evolving plumes. Here, a variety of release and site heterogeneity (sequential Gaussian permeability) conditions were investigated. Push-pull tracer tests were also explored as a means to provide localized in situ observations to refine these metric estimates. Here, two-dimensional aquifer cell experiments and mathematical modeling were used to quantify upscaled interphase mass transfer rates and the interplay between injection and extraction rates, local source zone architecture, and tracer

Characterizing multi-photon quantum interference with practical light sources and threshold single-photon detectors

Science.gov (United States)

Navarrete, Álvaro; Wang, Wenyuan; Xu, Feihu; Curty, Marcos

2018-04-01

The experimental characterization of multi-photon quantum interference effects in optical networks is essential in many applications of photonic quantum technologies, which include quantum computing and quantum communication as two prominent examples. However, such characterization often requires technologies which are beyond our current experimental capabilities, and today's methods suffer from errors due to the use of imperfect sources and photodetectors. In this paper, we introduce a simple experimental technique to characterize multi-photon quantum interference by means of practical laser sources and threshold single-photon detectors. Our technique is based on well-known methods in quantum cryptography which use decoy settings to tightly estimate the statistics provided by perfect devices. As an illustration of its practicality, we use this technique to obtain a tight estimation of both the generalized Hong‑Ou‑Mandel dip in a beamsplitter with six input photons and the three-photon coincidence probability at the output of a tritter.

Self characterization of a coded aperture array for neutron source imaging

Energy Technology Data Exchange (ETDEWEB)

Volegov, P. L., E-mail: volegov@lanl.gov; Danly, C. R.; Guler, N.; Merrill, F. E.; Wilde, C. H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States); Fittinghoff, D. N. [Livermore National Laboratory, Livermore, California 94550 (United States)

2014-12-15

The neutron imaging system at the National Ignition Facility (NIF) is an important diagnostic tool for measuring the two-dimensional size and shape of the neutrons produced in the burning deuterium-tritium plasma during the stagnation stage of inertial confinement fusion implosions. Since the neutron source is small (∼100 μm) and neutrons are deeply penetrating (>3 cm) in all materials, the apertures used to achieve the desired 10-μm resolution are 20-cm long, triangular tapers machined in gold foils. These gold foils are stacked to form an array of 20 apertures for pinhole imaging and three apertures for penumbral imaging. These apertures must be precisely aligned to accurately place the field of view of each aperture at the design location, or the location of the field of view for each aperture must be measured. In this paper we present a new technique that has been developed for the measurement and characterization of the precise location of each aperture in the array. We present the detailed algorithms used for this characterization and the results of reconstructed sources from inertial confinement fusion implosion experiments at NIF.

Acoustic holography as a metrological tool for characterizing medical ultrasound sources and fields

Science.gov (United States)

Sapozhnikov, Oleg A.; Tsysar, Sergey A.; Khokhlova, Vera A.; Kreider, Wayne

2015-01-01

Acoustic holography is a powerful technique for characterizing ultrasound sources and the fields they radiate, with the ability to quantify source vibrations and reduce the number of required measurements. These capabilities are increasingly appealing for meeting measurement standards in medical ultrasound; however, associated uncertainties have not been investigated systematically. Here errors associated with holographic representations of a linear, continuous-wave ultrasound field are studied. To facilitate the analysis, error metrics are defined explicitly, and a detailed description of a holography formulation based on the Rayleigh integral is provided. Errors are evaluated both for simulations of a typical therapeutic ultrasound source and for physical experiments with three different ultrasound sources. Simulated experiments explore sampling errors introduced by the use of a finite number of measurements, geometric uncertainties in the actual positions of acquired measurements, and uncertainties in the properties of the propagation medium. Results demonstrate the theoretical feasibility of keeping errors less than about 1%. Typical errors in physical experiments were somewhat larger, on the order of a few percent; comparison with simulations provides specific guidelines for improving the experimental implementation to reduce these errors. Overall, results suggest that holography can be implemented successfully as a metrological tool with small, quantifiable errors. PMID:26428789

Acoustic holography as a metrological tool for characterizing medical ultrasound sources and fields.

Science.gov (United States)

Sapozhnikov, Oleg A; Tsysar, Sergey A; Khokhlova, Vera A; Kreider, Wayne

2015-09-01

Acoustic holography is a powerful technique for characterizing ultrasound sources and the fields they radiate, with the ability to quantify source vibrations and reduce the number of required measurements. These capabilities are increasingly appealing for meeting measurement standards in medical ultrasound; however, associated uncertainties have not been investigated systematically. Here errors associated with holographic representations of a linear, continuous-wave ultrasound field are studied. To facilitate the analysis, error metrics are defined explicitly, and a detailed description of a holography formulation based on the Rayleigh integral is provided. Errors are evaluated both for simulations of a typical therapeutic ultrasound source and for physical experiments with three different ultrasound sources. Simulated experiments explore sampling errors introduced by the use of a finite number of measurements, geometric uncertainties in the actual positions of acquired measurements, and uncertainties in the properties of the propagation medium. Results demonstrate the theoretical feasibility of keeping errors less than about 1%. Typical errors in physical experiments were somewhat larger, on the order of a few percent; comparison with simulations provides specific guidelines for improving the experimental implementation to reduce these errors. Overall, results suggest that holography can be implemented successfully as a metrological tool with small, quantifiable errors.

Characterization of polar organic compounds and source analysis of fine organic aerosols in Hong Kong

Science.gov (United States)

Li, Yunchun

Organic aerosols, as an important fraction of airborne particulate mass, significantly affect the environment, climate, and human health. Compared with inorganic species, characterization of individual organic compounds is much less complete and comprehensive because they number in thousands or more and are diverse in chemical structures. The source contributions of organic aerosols are far from being well understood because they can be emitted from a variety of sources as well as formed from photochemical reactions of numerous precursors. This thesis work aims to improve the characterization of polar organic compounds and source apportionment analysis of fine organic carbon (OC) in Hong Kong, which consists of two parts: (1) An improved analytical method to determine monocarboxylic acids, dicarboxylic acids, ketocarboxylic acids, and dicarbonyls collected on filter substrates has been established. These oxygenated compounds were determined as their butyl ester or butyl acetal derivatives using gas chromatography-mass spectrometry. The new method made improvements over the original Kawamura method by eliminating the water extraction and evaporation steps. Aerosol materials were directly mixed with the BF 3/BuOH derivatization agent and the extracting solvent hexane. This modification improves recoveries for both the more volatile and the less water-soluble compounds. This improved method was applied to study the abundances and sources of these oxygenated compounds in PM2.5 aerosol samples collected in Hong Kong under different synoptic conditions during 2003-2005. These compounds account for on average 5.2% of OC (range: 1.4%-13.6%) on a carbon basis. Oxalic acid was the most abundant species. Six C2 and C3 oxygenated compounds, namely oxalic, malonic, glyoxylic, pyruvic acids, glyoxal, and methylglyoxal, dominated this suite of oxygenated compounds. More efforts are therefore suggested to focus on these small compounds in understanding the role of oxygenated

Nutrient patterns and their food sources in an International Study Setting: report from the EPIC study.

Directory of Open Access Journals (Sweden)

Aurelie Moskal

Full Text Available Compared to food patterns, nutrient patterns have been rarely used particularly at international level. We studied, in the context of a multi-center study with heterogeneous data, the methodological challenges regarding pattern analyses.We identified nutrient patterns from food frequency questionnaires (FFQ in the European Prospective Investigation into Cancer and Nutrition (EPIC Study and used 24-hour dietary recall (24-HDR data to validate and describe the nutrient patterns and their related food sources. Associations between lifestyle factors and the nutrient patterns were also examined. Principal component analysis (PCA was applied on 23 nutrients derived from country-specific FFQ combining data from all EPIC centers (N = 477,312. Harmonized 24-HDRs available for a representative sample of the EPIC populations (N = 34,436 provided accurate mean group estimates of nutrients and foods by quintiles of pattern scores, presented graphically. An overall PCA combining all data captured a good proportion of the variance explained in each EPIC center. Four nutrient patterns were identified explaining 67% of the total variance: Principle component (PC 1 was characterized by a high contribution of nutrients from plant food sources and a low contribution of nutrients from animal food sources; PC2 by a high contribution of micro-nutrients and proteins; PC3 was characterized by polyunsaturated fatty acids and vitamin D; PC4 was characterized by calcium, proteins, riboflavin, and phosphorus. The nutrients with high loadings on a particular pattern as derived from country-specific FFQ also showed high deviations in their mean EPIC intakes by quintiles of pattern scores when estimated from 24-HDR. Center and energy intake explained most of the variability in pattern scores.The use of 24-HDR enabled internal validation and facilitated the interpretation of the nutrient patterns derived from FFQs in term of food sources. These outcomes open research

Nutrient patterns and their food sources in an International Study Setting: report from the EPIC study.

Science.gov (United States)

Moskal, Aurelie; Pisa, Pedro T; Ferrari, Pietro; Byrnes, Graham; Freisling, Heinz; Boutron-Ruault, Marie-Christine; Cadeau, Claire; Nailler, Laura; Wendt, Andrea; Kühn, Tilman; Boeing, Heiner; Buijsse, Brian; Tjønneland, Anne; Halkjær, Jytte; Dahm, Christina C; Chiuve, Stephanie E; Quirós, Jose R; Buckland, Genevieve; Molina-Montes, Esther; Amiano, Pilar; Huerta Castaño, José M; Gurrea, Aurelio Barricarte; Khaw, Kay-Tee; Lentjes, Marleen A; Key, Timothy J; Romaguera, Dora; Vergnaud, Anne-Claire; Trichopoulou, Antonia; Bamia, Christina; Orfanos, Philippos; Palli, Domenico; Pala, Valeria; Tumino, Rosario; Sacerdote, Carlotta; de Magistris, Maria Santucci; Bueno-de-Mesquita, H Bas; Ocké, Marga C; Beulens, Joline W J; Ericson, Ulrika; Drake, Isabel; Nilsson, Lena M; Winkvist, Anna; Weiderpass, Elisabete; Hjartåker, Anette; Riboli, Elio; Slimani, Nadia

2014-01-01

Compared to food patterns, nutrient patterns have been rarely used particularly at international level. We studied, in the context of a multi-center study with heterogeneous data, the methodological challenges regarding pattern analyses. We identified nutrient patterns from food frequency questionnaires (FFQ) in the European Prospective Investigation into Cancer and Nutrition (EPIC) Study and used 24-hour dietary recall (24-HDR) data to validate and describe the nutrient patterns and their related food sources. Associations between lifestyle factors and the nutrient patterns were also examined. Principal component analysis (PCA) was applied on 23 nutrients derived from country-specific FFQ combining data from all EPIC centers (N = 477,312). Harmonized 24-HDRs available for a representative sample of the EPIC populations (N = 34,436) provided accurate mean group estimates of nutrients and foods by quintiles of pattern scores, presented graphically. An overall PCA combining all data captured a good proportion of the variance explained in each EPIC center. Four nutrient patterns were identified explaining 67% of the total variance: Principle component (PC) 1 was characterized by a high contribution of nutrients from plant food sources and a low contribution of nutrients from animal food sources; PC2 by a high contribution of micro-nutrients and proteins; PC3 was characterized by polyunsaturated fatty acids and vitamin D; PC4 was characterized by calcium, proteins, riboflavin, and phosphorus. The nutrients with high loadings on a particular pattern as derived from country-specific FFQ also showed high deviations in their mean EPIC intakes by quintiles of pattern scores when estimated from 24-HDR. Center and energy intake explained most of the variability in pattern scores. The use of 24-HDR enabled internal validation and facilitated the interpretation of the nutrient patterns derived from FFQs in term of food sources. These outcomes open research opportunities and

Characterization and source identification of fine particulate matter in urban Beijing during the 2015 Spring Festival.

Science.gov (United States)

Ji, Dongsheng; Cui, Yang; Li, Liang; He, Jun; Wang, Lili; Zhang, Hongliang; Wang, Wan; Zhou, Luxi; Maenhaut, Willy; Wen, Tianxue; Wang, Yuesi

2018-07-01

The Spring Festival (SF) is the most important holiday in China for family reunion and tourism. During the 2015 SF an intensive observation campaign of air quality was conducted to study the impact of the anthropogenic activities and the dynamic characteristics of the sources. During the study period, pollution episodes frequently occurred with 12days exceeding the Chinese Ambient Air Quality Standards for 24-h average PM 2.5 (75μg/m 3 ), even 8days with exceeding 150μg/m 3 . The daily maximum PM 2.5 concentration reached 350μg/m 3 while the hourly minimum visibility was <0.8km. Three pollution episodes were selected for detailed analysis including chemical characterization and diurnal variation of the PM 2.5 and its chemical composition, and sources were identified using the Positive Matrix Factorization model. The first episode occurring before the SF was characterized by more formation of SO 4 2- and NO 3 - and high crustal enrichment factors for Ag, As, Cd, Cu, Hg, Pb, Se and Zn and seven categories of pollution sources were identified, whereby vehicle emission contributed 38% to the PM 2.5 . The second episode occurring during the SF was affected heavily by large-scale firework emissions, which led to a significant increase in SO 4 2- , Cl - , OC, K and Ba; these emissions were the largest contributor to the PM 2.5 accounting for 36%. During the third episode occurring after the SF, SO 4 2- , NO 3 - , NH 4 + and OC were the major constituents of the PM 2.5 and the secondary source was the dominant source with a contribution of 46%. The results provide a detailed understanding on the variation in occurrence, chemical composition and sources of the PM 2.5 as well as of the gaseous pollutants affected by the change in anthropogenic activities in Beijing throughout the SF. They highlight the need for limiting the firework emissions during China's most important traditional festival. Copyright © 2018 Elsevier B.V. All rights reserved.

Characterization of the neutron sources storage pool of the Neutron Standards Laboratory, using Montecarlo Techniques

International Nuclear Information System (INIS)

Campo Blanco, X.

2015-01-01

The development of irradiation damage resistant materials is one of the most important open fields in the design of experimental facilities and conceptual nucleoelectric fusion plants. The Neutron Standards Laboratory aims to contribute to this development by allowing the neutron irradiation of materials in its calibration neutron sources storage pool. For this purposes, it is essential to characterize the pool itself in terms of neutron fluence and spectra due to the calibration neutron sources. In this work, the main features of this facility are presented and the characterization of the storage pool is carried out. Finally, an application is shown of the obtained results to the neutron irradiation of material.

Characterization of the γ background in epithermal neutron scattering measurements at pulsed neutron sources

International Nuclear Information System (INIS)

Pietropaolo, A.; Tardocchi, M.; Schooneveld, E.M.; Senesi, R.

2006-01-01

This paper reports the characterization of the different components of the γ background in epithermal neutron scattering experiments at pulsed neutron sources. The measurements were performed on the VESUVIO spectrometer at ISIS spallation neutron source. These measurements, carried out with a high purity germanium detector, aim to provide detailed information for the investigation of the effect of the γ energy discrimination on the signal-to-background ratio. It is shown that the γ background is produced by different sources that can be identified with their relative time structure and relative weight

Characterization of polarized electrons coming from helium post-discharge source

International Nuclear Information System (INIS)

Zerhouni, R.O.

1996-02-01

The objective of this thesis is the characterization of the polarized electron source developed at Orsay and foreseen to be coupled to a cw accelerator for nuclear physics experiments. The principle of operation of this source relies on the chemo-ionization reaction between optically aligned helium triplet metastable atoms and CO 2 molecules. The helium metastable atoms are generated by injection of purified helium into a 2,45 GHz micro-wave discharge. They are optically pumped using two beams of 1,083 micro-meter resonant radiation, one circularly and the other linearly polarized. Both beams are delivered by a high power LNA laser. The metastable atomic beam interacts with a dense (10 13 cm -3 ) spin singlet CO 2 target. A fraction of the produced polarized electrons is extracted and collimated by electrostatic optics. Either to the Mott polarimeter or to the Faraday cup in order to measure the electron polarization and extracted current. For current intensities of 100 micro-Amperes, the electronic polarization reaches 62 % and shows that this type of source has reached the same high competitive level as the most performing GaAs ones. Additionally, the optical properties of the extracted beam are found to be excellent. These properties (energy spread and emittance) reflect the electron energy distribution at the chemo-ionization region. The upper limit of the beam's energy spread is 0.24 eV since this value characterizes our instrumental resolution. The average normalized emittance is found to be 0.6 pi mm-mrad. These values satisfy the requirements of most cw accelerators. All the measurements were performed at low electron beam transport energies (1 to 2 KeV). (author). 105 refs., 54 figs., 4 tabs

Soil sample collection and analysis for the Fugitive Dust Characterization Study

Science.gov (United States)

Ashbaugh, Lowell L.; Carvacho, Omar F.; Brown, Michael S.; Chow, Judith C.; Watson, John G.; Magliano, Karen C.

A unique set of soil samples was collected as part of the Fugitive Dust Characterization Study. The study was carried out to establish whether or not source profiles could be constructed using novel analytical methods that could distinguish soil dust sources from each other. The soil sources sampled included fields planted in cotton, almond, tomato, grape, and safflower, dairy and feedlot facilities, paved and unpaved roads (both urban and rural), an agricultural staging area, disturbed land with salt buildup, and construction areas where the topsoil had been removed. The samples were collected using a systematic procedure designed to reduce sampling bias, and were stored frozen to preserve possible organic signatures. For this paper the samples were characterized by particle size (percent sand, silt, and clay), dry silt content (used in EPA-recommended fugitive dust emission factors), carbon and nitrogen content, and potential to emit both PM 10 and PM 2.5. These are not the "novel analytical methods" referred to above; rather, it was the basic characterization of the samples to use in comparing analytical methods by other scientists contracted to the California Air Resources Board. The purpose of this paper is to document the methods used to collect the samples, the collection locations, the analysis of soil type and potential to emit PM 10, and the sample variability, both within field and between fields of the same crop type.

Spectrally resolved, broadband frequency response characterization of photodetectors using continuous-wave supercontinuum sources

Science.gov (United States)

Choudhury, Vishal; Prakash, Roopa; Nagarjun, K. P.; Supradeepa, V. R.

2018-02-01

A simple and powerful method using continuous wave supercontinuum lasers is demonstrated to perform spectrally resolved, broadband frequency response characterization of photodetectors in the NIR Band. In contrast to existing techniques, this method allows for a simple system to achieve the goal, requiring just a standard continuous wave(CW) high-power fiber laser source and an RF spectrum analyzer. From our recent work, we summarize methods to easily convert any high-power fiber laser into a CW supercontinuum. These sources in the time domain exhibit interesting properties all the way down to the femtosecond time scale. This enables measurement of broadband frequency response of photodetectors while the wide optical spectrum of the supercontinuum can be spectrally filtered to obtain this information in a spectrally resolved fashion. The method involves looking at the RF spectrum of the output of a photodetector under test when incident with the supercontinuum. By using prior knowledge of the RF spectrum of the source, the frequency response can be calculated. We utilize two techniques for calibration of the source spectrum, one using a prior measurement and the other relying on a fitted model. Here, we characterize multiple photodetectors from 150MHz bandwidth to >20GHz bandwidth at multiple bands in the NIR region. We utilize a supercontinuum source spanning over 700nm bandwidth from 1300nm to 2000nm. For spectrally resolved measurement, we utilize multiple wavelength bands such as around 1400nm and 1600nm. Interesting behavior was observed in the frequency response of the photodetectors when comparing broadband spectral excitation versus narrower band excitation.

Characterization and application of a laser-driven intense pulsed neutron source using Trident

Energy Technology Data Exchange (ETDEWEB)

Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-08-25

A team of Los Alamos researchers supported a final campaign to use the Trident laser to produce neutrons, contributed their multidisciplinary expertise to experimentally assess if laser-driven neutron sources can be useful for MaRIE. MaRIE is the Laboratory’s proposed experimental facility for the study of matter-radiation interactions in extremes. Neutrons provide a radiographic probe that is complementary to x-rays and protons, and can address imaging challenges not amenable to those beams. The team's efforts characterize the Laboratory’s responsiveness, flexibility, and ability to apply diverse expertise where needed to perform successful complex experiments.

The synthesis conditions, characterizations and thermal degradation studies of an etherified starch from an unconventional source

International Nuclear Information System (INIS)

Lawal, O.S.; Lechner, M.D.; Kulicke, W.M.

2008-05-01

Starch isolated from an under-utilized legume plant (pigeon pea) was carboxymethylated. Influences of reaction parameters were investigated on the degree of substitution (DS) and the reaction efficiency (RE). Studies showed that optimal DS of 1.12 could be reached at reaction efficiency of 80.6 % in isopropanol-water reaction medium (40 deg. C, 3h). The scanning electron microscopy showed that after carboxymethylation, the granular appearance of the native starch was distorted. Wide-angle X-ray diffractometry revealed that crystallinity was reduced significantly after carboxymethylation. The infrared spectra revealed new bands in the carboxymethyl starch at ν =1600, 1426 and 1324 cm -1 and they were attributed to carbonyl functional groups vibration, -CH2 scissoring and OH bending vibration respectively. Broad band 13 C NMR of carboxymethyl starch showed intense peak at δ 180.3 ppm and it was assigned for carbonyl carbon on the carboxymethyl substituent on the AGU (Anhydroglucose Unit). DEPT (Distortionless Enhancement by Polarization Transfer) 135 NMR showed negative signals which correspond to methylene carbons on the AGU. The differential scanning calorimetry (DSC) suggests loss of crystallinity after carboxymethylation. Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA) show that thermal stability improved after carboxymethylation. The study provides information on the preparation and characterization of a biomaterial from a new source which could be used alone or in the preparation of other functional polymers for diverse polymer applications. (author)

Characterization of our source of polarization-entangled photons

Science.gov (United States)

Adenier, Guillaume

2012-12-01

We present our source of polarization entangled photons, which consist of orthogonally polarized and collinear parametric down converted photons sent to the same input of a nonpolarizing beam splitter. We show that a too straightforward characterization of the quantum state cannot account for all the experimental observations, in particular for the behavior of the doublecounts, which are the coincidences produced whenever both photons are dispatched by the beam splitter to the same measuring station (either Alice or Bob). We argue that in order to account for all observations, the state has to be entangled in polarization before the non-polarizing beam splitter, and we discuss the intriguing and nevertheless essential role of the time-compensation required to obtain such a polarization entanglement.

A hydrogeochemical study of rain water to characterize the source of atmospheric pollutants at Jodhpur - desert city of India (abstract)

International Nuclear Information System (INIS)

Shrivastava, K.L.; Ojha, S.K.

1999-01-01

A study was undertaken has been conducted to determined the physical parameters and chemical species in the first precipitants of the season at desert city of Jodhpur to understand firstly, the degree of pollutants in the atmosphere and secondly to identity the minerals/pollutants of the atmosphere to characterize its possible source of origin. The precipitate samples for cations and other physical and chemical parameters by standard analytical methods. The results obtained on turbidity, conductivity, total dissolved solids and the ratio of total dissolved solids and conductivity, show a moderate degree of pollutants at all the four sites, A, B, C and D but slightly higher at C and D sites. The concentration of various water-soluble chemical species present in the precipitates, specially a balance between acidic and basic constituents decides its pH value. Hydrogen ions are mainly responsible for acidification of rain waters and are derived chiefly from oxidation of SO/sub 2/ and NO/sub 2/ to from H/sub 2/SO/sub 4/ and HNO/sub 3/ respectively. Hence a correlation study carried out between H/sup */and SO/sub 4//sup --/, NO/sub 3/ and Cl. Result shows no strong correlation between H/sup +/ and Cl/up -/. A group of strongly corrected elements Cl, Na/sup +/,K/sup +/ and Mg/sup ++/ were observed representing a similar source of their origin. The atmospheric desert dust components chiefly consist of quartz, mica flakes, clays like illite, kaolinite etc., and especially clays, may neutralize the acidity of precipitates via H/sup +/ exchange. Some minerals like Halite, Gypsum, Dolomite, Calcite may get slightly dissolved in the rainwater to replace H/sup +/ ions and so, impart alkalinity. Thus, it is logical to believe that the cations may have been derived originally from some of the geological source. Some rations like Cl/Na, Mg/Na, Ca/Na are known to have been used in characterization of the source. As expected in the atmosphere of desert city, like Jodhpur, the solid

Monte Carlo dosimetric characterization of the Flexisource Co-60 high-dose-rate brachytherapy source using PENELOPE.

Science.gov (United States)

Almansa, Julio F; Guerrero, Rafael; Torres, Javier; Lallena, Antonio M

60 Co sources have been commercialized as an alternative to 192 Ir sources for high-dose-rate (HDR) brachytherapy. One of them is the Flexisource Co-60 HDR source manufactured by Elekta. The only available dosimetric characterization of this source is that of Vijande et al. [J Contemp Brachytherapy 2012; 4:34-44], whose results were not included in the AAPM/ESTRO consensus document. In that work, the dosimetric quantities were calculated as averages of the results obtained with the Geant4 and PENELOPE Monte Carlo (MC) codes, though for other sources, significant differences have been quoted between the values obtained with these two codes. The aim of this work is to perform the dosimetric characterization of the Flexisource Co-60 HDR source using PENELOPE. The MC simulation code PENELOPE (v. 2014) has been used. Following the recommendations of the AAPM/ESTRO report, the radial dose function, the anisotropy function, the air-kerma strength, the dose rate constant, and the absorbed dose rate in water have been calculated. The results we have obtained exceed those of Vijande et al. In particular, the absorbed dose rate constant is ∼0.85% larger. A similar difference is also found in the other dosimetric quantities. The effect of the electrons emitted in the decay of 60 Co, usually neglected in this kind of simulations, is significant up to the distances of 0.25 cm from the source. The systematic and significant differences we have found between PENELOPE results and the average values found by Vijande et al. point out that the dosimetric characterizations carried out with the various MC codes should be provided independently. Copyright © 2017 American Brachytherapy Society. Published by Elsevier Inc. All rights reserved.

Characterization and variability of the main oceanic sources of moisture

Science.gov (United States)

Castillo Rodriguez, R.; Nieto, R.; Gimeno, L.; Drumond, A.

2012-04-01

Transport of water vapor in the atmosphere from regions of net evaporation to regions of net precipitation is an important part of the hydrological cycle. The aim of this study is to track variations of atmospheric moisture along 10-days trajectories of air masses to identify where continental regions are affected by precipitation originating from specific oceanic regions. The proceeding was based on the method developed by Stohl and James 2004, 2005, which used the Lagrangian particle dispersion model FLEXPART v8.0 and reanalysis data ERA-40 from the European Centre for Medium-Range Weather Forecast (ECMWF). These source regions, selecting according to the largest values of divergence of the vertically integrated moisture flux are: India, North and South Pacific, North and South Atlantic oceans, Mexico-Caribbean, the Mediterranean, the Arabian, the Coral and the Red seas, as well as the Agulhas (in the waters surrounding South Africa) and the Zanzibar Current regions. And they were defined based on the threshold of 750 mm/yr. We investigated the moisture sinks associated with each one of these evaporative sources for a period of 21 years (1980-2000) in a seasonal scale using correlations and the statistical mean. In addition, we characterized the influence of the El Niño-Southern Oscillation over the transport of moisture from the source regions selected with the composites technique from the month of june to the month of may over the years 1984-1985, 1988-1989, 1995-1996, 1998-1999, 1999-2000 in the Niña phase and 1982-1983, 1986-1987, 1991-1992, 1994-1995, 1997-1998 in the Niño phase.

Sources of uncertainty in characterizing health risks from flare emissions

International Nuclear Information System (INIS)

Hrudey, S.E.

2000-01-01

The assessment of health risks associated with gas flaring was the focus of this paper. Health risk assessments for environmental decision-making includes the evaluation of scientific data to identify hazards and to determine dose-response assessments, exposure assessments and risk characterization. Gas flaring has been the cause for public health concerns in recent years, most notably since 1996 after a published report by the Alberta Research Council. Some of the major sources of uncertainty associated with identifying hazardous contaminants in flare emissions were discussed. Methods to predict human exposures to emitted contaminants were examined along with risk characterization of predicted exposures to several identified contaminants. One of the problems is that elemental uncertainties exist regarding flare emissions which places limitations of the degree of reassurance that risk assessment can provide, but risk assessment can nevertheless offer some guidance to those responsible for flare emissions

Physics-electrical hybrid model for real time impedance matching and remote plasma characterization in RF plasma sources.

Science.gov (United States)

Sudhir, Dass; Bandyopadhyay, M; Chakraborty, A

2016-02-01

Plasma characterization and impedance matching are an integral part of any radio frequency (RF) based plasma source. In long pulse operation, particularly in high power operation where plasma load may vary due to different reasons (e.g. pressure and power), online tuning of impedance matching circuit and remote plasma density estimation are very useful. In some cases, due to remote interfaces, radio activation and, due to maintenance issues, power probes are not allowed to be incorporated in the ion source design for plasma characterization. Therefore, for characterization and impedance matching, more remote schemes are envisaged. Two such schemes by the same authors are suggested in these regards, which are based on air core transformer model of inductive coupled plasma (ICP) [M. Bandyopadhyay et al., Nucl. Fusion 55, 033017 (2015); D. Sudhir et al., Rev. Sci. Instrum. 85, 013510 (2014)]. However, the influence of the RF field interaction with the plasma to determine its impedance, a physics code HELIC [D. Arnush, Phys. Plasmas 7, 3042 (2000)] is coupled with the transformer model. This model can be useful for both types of RF sources, i.e., ICP and helicon sources.

Applications of Ground-based Mobile Atmospheric Monitoring: Real-time Characterization of Source Emissions and Ambient Concentrations

Science.gov (United States)

Goetz, J. Douglas

Gas and particle phase atmospheric pollution are known to impact human and environmental health as well as contribute to climate forcing. While many atmospheric pollutants are regulated or controlled in the developed world uncertainty still remains regarding the impacts from under characterized emission sources, the interaction of anthropogenic and naturally occurring pollution, and the chemical and physical evolution of emissions in the atmosphere, among many other uncertainties. Because of the complexity of atmospheric pollution many types of monitoring have been implemented in the past, but none are capable of perfectly characterizing the atmosphere and each monitoring type has known benefits and disadvantages. Ground-based mobile monitoring with fast-response in-situ instrumentation has been used in the past for a number of applications that fill data gaps not possible with other types of atmospheric monitoring. In this work, ground-based mobile monitoring was implemented to quantify emissions from under characterized emission sources using both moving and portable applications, and used in a novel way for the characterization of ambient concentrations. In the Marcellus Shale region of Pennsylvania two mobile platforms were used to estimate emission rates from infrastructure associated with the production and transmission of natural gas using two unique methods. One campaign investigated emissions of aerosols, volatile organic compounds (VOCs), methane, carbon monoxide (CO), nitrogen dioxide (NO2), and carbon dioxide (CO 2) from natural gas wells, well development practices, and compressor stations using tracer release ratio methods and a developed fenceline tracer release correction factor. Another campaign investigated emissions of methane from Marcellus Shale gas wells and infrastructure associated with two large national transmission pipelines using the "Point Source Gaussian" method described in the EPA OTM-33a. During both campaigns ambient concentrations

Assessing Model Characterization of Single Source ...

Science.gov (United States)

Aircraft measurements made downwind from specific coal fired power plants during the 2013 Southeast Nexus field campaign provide a unique opportunity to evaluate single source photochemical model predictions of both O3 and secondary PM2.5 species. The model did well at predicting downwind plume placement. The model shows similar patterns of an increasing fraction of PM2.5 sulfate ion to the sum of SO2 and PM2.5 sulfate ion by distance from the source compared with ambient based estimates. The model was less consistent in capturing downwind ambient based trends in conversion of NOX to NOY from these sources. Source sensitivity approaches capture near-source O3 titration by fresh NO emissions, in particular subgrid plume treatment. However, capturing this near-source chemical feature did not translate into better downwind peak estimates of single source O3 impacts. The model estimated O3 production from these sources but often was lower than ambient based source production. The downwind transect ambient measurements, in particular secondary PM2.5 and O3, have some level of contribution from other sources which makes direct comparison with model source contribution challenging. Model source attribution results suggest contribution to secondary pollutants from multiple sources even where primary pollutants indicate the presence of a single source. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, deci

Earthquake Source Spectral Study beyond the Omega-Square Model

Science.gov (United States)

Uchide, T.; Imanishi, K.

2017-12-01

Earthquake source spectra have been used for characterizing earthquake source processes quantitatively and, at the same time, simply, so that we can analyze the source spectra for many earthquakes, especially for small earthquakes, at once and compare them each other. A standard model for the source spectra is the omega-square model, which has the flat spectrum and the falloff inversely proportional to the square of frequencies at low and high frequencies, respectively, which are bordered by a corner frequency. The corner frequency has often been converted to the stress drop under the assumption of circular crack models. However, recent studies claimed the existence of another corner frequency [Denolle and Shearer, 2016; Uchide and Imanishi, 2016] thanks to the recent development of seismic networks. We have found that many earthquakes in areas other than the area studied by Uchide and Imanishi [2016] also have source spectra deviating from the omega-square model. Another part of the earthquake spectra we now focus on is the falloff rate at high frequencies, which will affect the seismic energy estimation [e.g., Hirano and Yagi, 2017]. In June, 2016, we deployed seven velocity seismometers in the northern Ibaraki prefecture, where the shallow crustal seismicity mainly with normal-faulting events was activated by the 2011 Tohoku-oki earthquake. We have recorded seismograms at 1000 samples per second and at a short distance from the source, so that we can investigate the high-frequency components of the earthquake source spectra. Although we are still in the stage of discovery and confirmation of the deviation from the standard omega-square model, the update of the earthquake source spectrum model will help us systematically extract more information on the earthquake source process.

Characterization of Niobium Oxide Films Deposited by High Target Utilization Sputter Sources

International Nuclear Information System (INIS)

Chow, R; Ellis, A D; Loomis, G E; Rana, S I

2007-01-01

High quality, refractory metal, oxide coatings are required in a variety of applications such as laser optics, micro-electronic insulating layers, nano-device structures, electro-optic multilayers, sensors and corrosion barriers. A common oxide deposition technique is reactive sputtering because the kinetic mechanism vaporizes almost any solid material in vacuum. Also, the sputtered molecules have higher energies than those generated from thermal evaporation, and so the condensates are smoother and denser than those from thermally-evaporated films. In the typical sputtering system, target erosion is a factor that drives machine availability. In some situations such as nano-layered capacitors, where the device's performance characteristics depends on thick layers, target life becomes a limiting factor on the maximizing device functionality. The keen interest to increase target utilization in sputtering has been addressed in a variety of ways such as target geometry, rotating magnets, and/or shaped magnet arrays. Also, a recent sputtering system has been developed that generates a high density plasma, directs the plasma beam towards the target in a uniform fashion, and erodes the target in a uniform fashion. The purpose of this paper is to characterize and compare niobia films deposited by two types of high target utilization sputtering sources, a rotating magnetron and a high density plasma source. The oxide of interest in this study is niobia because of its high refractive index. The quality of the niobia films were characterized spectroscopically in optical transmission, ellipsometrically, and chemical stoichiometry with X-ray photo-electron spectroscopy. The refractive index, extinction coefficients, Cauchy constants were derived from the ellipsometric modeling. The mechanical properties of coating density and stress are also determined

Combining land use information and small stream sampling with PCR-based methods for better characterization of diffuse sources of human fecal pollution.

Science.gov (United States)

Peed, Lindsay A; Nietch, Christopher T; Kelty, Catherine A; Meckes, Mark; Mooney, Thomas; Sivaganesan, Mano; Shanks, Orin C

2011-07-01

Diffuse sources of human fecal pollution allow for the direct discharge of waste into receiving waters with minimal or no treatment. Traditional culture-based methods are commonly used to characterize fecal pollution in ambient waters, however these methods do not discern between human and other animal sources of fecal pollution making it difficult to identify diffuse pollution sources. Human-associated quantitative real-time PCR (qPCR) methods in combination with low-order headwatershed sampling, precipitation information, and high-resolution geographic information system land use data can be useful for identifying diffuse source of human fecal pollution in receiving waters. To test this assertion, this study monitored nine headwatersheds over a two-year period potentially impacted by faulty septic systems and leaky sanitary sewer lines. Human fecal pollution was measured using three different human-associated qPCR methods and a positive significant correlation was seen between abundance of human-associated genetic markers and septic systems following wet weather events. In contrast, a negative correlation was observed with sanitary sewer line densities suggesting septic systems are the predominant diffuse source of human fecal pollution in the study area. These results demonstrate the advantages of combining water sampling, climate information, land-use computer-based modeling, and molecular biology disciplines to better characterize diffuse sources of human fecal pollution in environmental waters.

Open Source Platform Application to Groundwater Characterization and Monitoring

Science.gov (United States)

Ntarlagiannis, D.; Day-Lewis, F. D.; Falzone, S.; Lane, J. W., Jr.; Slater, L. D.; Robinson, J.; Hammett, S.

2017-12-01

Groundwater characterization and monitoring commonly rely on the use of multiple point sensors and human labor. Due to the number of sensors, labor, and other resources needed, establishing and maintaining an adequate groundwater monitoring network can be both labor intensive and expensive. To improve and optimize the monitoring network design, open source software and hardware components could potentially provide the platform to control robust and efficient sensors thereby reducing costs and labor. This work presents early attempts to create a groundwater monitoring system incorporating open-source software and hardware that will control the remote operation of multiple sensors along with data management and file transfer functions. The system is built around a Raspberry PI 3, that controls multiple sensors in order to perform on-demand, continuous or `smart decision' measurements while providing flexibility to incorporate additional sensors to meet the demands of different projects. The current objective of our technology is to monitor exchange of ionic tracers between mobile and immobile porosity using a combination of fluid and bulk electrical-conductivity measurements. To meet this objective, our configuration uses four sensors (pH, specific conductance, pressure, temperature) that can monitor the fluid electrical properties of interest and guide the bulk electrical measurement. This system highlights the potential of using open source software and hardware components for earth sciences applications. The versatility of the system makes it ideal for use in a large number of applications, and the low cost allows for high resolution (spatially and temporally) monitoring.

Characterization, weathering, and application of sesquiterpanes to source identification of spilled oils

International Nuclear Information System (INIS)

Wang, Z.D.; Yang, C.; Fingas, M.; Hollebone, B.P.; Landriault, M.

2005-01-01

Sesquiterpanes are a component of crude oils and ancient sediments. This study examined the feasibility of using them as bicyclic biomarkers for fingerprinting and identifying unknown lighter petroleum product spills. The study identified and characterize sesquiterpanes in crude oils and petroleum products. The distributions of sesquiterpanes in different oils, oil distillation fractions and refined products were also studied along with the effects of evaporative weathering on the distribution and concentration of sesquiterpanes. Several diagnostic indexes of sesquiterpanes were developed for oil correlation and differentiation. Most high-molecular weight biomarkers are removed from lighter petroleum products during the refining process. Therefore, high boiling point pentacyclic triterpanes and steranes are often absent in lighter petroleum products. However, the smaller bicyclic sesquiterpanes such as drimane and eudesmane are highly concentrated in petroleum products such as light gas oil. Gas chromatography and mass spectrometry analysis of these bicyclic biomarkers can be used to correlate, differentiate and identify the source for lighter petroleum products. 15 refs., 2 tabs., 9 figs

Quantitative characterization of urban sources of organic aerosol by high-resolution gas chromatography

International Nuclear Information System (INIS)

Hildemann, L.M.; Mazurek, M.A.; Cass, G.R.; Simoneit, B.R.T.

1991-01-01

Fine aerosol emissions have been collected from a variety of urban combustion sources, including an industrial boiler, a fireplace, automobiles, diesel trucks, gas-fired home appliances, and meat cooking operations, by use of a dilution sampling system. Other sampling techniques have been utilized to collect fine aerosol samples of paved road dust, brake wear, tire wear, cigarette smoke, tar pot emissions, and vegetative detritus. The organic matter contained in each of these samples has been analyzed via high-resolution gas chromatography. By use of a simple computational approach, a quantitative, 50-parameter characterization of the elutable fine organic aerosol emitted from each source type has been determined. The organic mass distribution fingerprints obtained by this approach are shown to differ significantly from each other for most of the source types tested, using hierarchical cluster analysis

Lead isotopic fingerprinting of aerosols to characterize the sources of atmospheric lead in an industrial city of India

Science.gov (United States)

Sen, Indra S.; Bizimis, Michael; Tripathi, Sachchida Nand; Paul, Debajyoti

2016-03-01

Anthropogenic Pb in the environment is primarily sourced from combustion of fossil fuel and high-temperature industries such as smelters. Identifying the sources and pathways of anthropogenic Pb in the environment is important because Pb toxicity is known to have adverse effects on human health. Pb pollution sources for America, Europe, and China are well documented. However, sources of atmospheric Pb are unknown in India, particularly after leaded gasoline was phased out in 2000. India has a developing economy with a rapidly emerging automobile and high temperature industry, and anthropogenic Pb emission is expected to rise in the next decade. In this study, we report on the Pb-isotope compositions and trace metal ratios of airborne particulates collected in Kanpur, a large city in northern part of India. The study shows that the PM10 aerosols had elevated concentration of Cd, Pb, Zn, As, and Cu in the Kanpur area, however their concentrations are well below the United States Environmental Protection Agency chronic exposure limit. Lead isotopic and trace metal data reveal industrial emission as the plausible source of anthropogenic Pb in the atmosphere in Kanpur. However, Pb isotopic compositions of potential source end-members are required to fully evaluate Pb contamination in India over time. This is the first study that characterizes the isotopic composition of atmospheric Pb in an Indian city after leaded gasoline was phased out by 2000.

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.

Seismic source characterization for the 2014 update of the U.S. National Seismic Hazard Model

Science.gov (United States)

Moschetti, Morgan P.; Powers, Peter; Petersen, Mark D.; Boyd, Oliver; Chen, Rui; Field, Edward H.; Frankel, Arthur; Haller, Kathleen; Harmsen, Stephen; Mueller, Charles S.; Wheeler, Russell; Zeng, Yuehua

2015-01-01

We present the updated seismic source characterization (SSC) for the 2014 update of the National Seismic Hazard Model (NSHM) for the conterminous United States. Construction of the seismic source models employs the methodology that was developed for the 1996 NSHM but includes new and updated data, data types, source models, and source parameters that reflect the current state of knowledge of earthquake occurrence and state of practice for seismic hazard analyses. We review the SSC parameterization and describe the methods used to estimate earthquake rates, magnitudes, locations, and geometries for all seismic source models, with an emphasis on new source model components. We highlight the effects that two new model components—incorporation of slip rates from combined geodetic-geologic inversions and the incorporation of adaptively smoothed seismicity models—have on probabilistic ground motions, because these sources span multiple regions of the conterminous United States and provide important additional epistemic uncertainty for the 2014 NSHM.

Characterization of emissions sources in the California-Mexico Border Region during Cal-Mex 2010

Science.gov (United States)

Zavala, M. A.; Lei, W.; Li, G.; Bei, N.; Barrera, H.; Tejeda, D.; Molina, L. T.; Cal-Mex 2010 Emissions Team

2010-12-01

The California-Mexico border region provides an opportunity to evaluate the characteristics of the emission processes in rapidly expanding urban areas where intensive international trade and commerce activities occur. Intense anthropogenic activities, biomass burning, as well as biological and geological sources significantly contribute to high concentration levels of particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), nitrogen oxides (NOx), volatile organic compounds (VOCs), air toxics, and ozone observed in the California-US Baja California-Mexico border region. The continued efforts by Mexico and US for improving and updating the emissions inventories in the sister cities of San Diego-Tijuana and Calexico-Mexicali has helped to understand the emission processes in the border region. In addition, the recent Cal-Mex 2010 field campaign included a series of measurements aimed at characterizing the emissions from major sources in the California-Mexico border region. In this work we will present our analyzes of the data obtained during Cal-Mex 2010 for the characterization of the emission sources and their use for the evaluation of the recent emissions inventories for the Mexican cities of Tijuana and Mexicali. The developed emissions inventories will be implemented in concurrent air quality modeling efforts for understanding the physical and chemical transformations of air pollutants in the California-Mexico border region and their impacts.

Reactor-building-basement radionuclide and source distribution studies. Volume 3

International Nuclear Information System (INIS)

Cox, T.E.; Horan, J.T.; Worku, G.

1983-06-01

The Three Mile Island Unit 2 (TMI-2) Reactor Building basement has been sampled several times since August 1979. This report compiles the analytical results and sample history for the liquid and solid samples obtained to date. In addition, basement radiation levels were also obtained using thermoluminescent dosimeters (TLDs). The data obtained will provide information to support ongoing mass balance and source term studies and will aid in characterizing the 282-ft elevation for decontamination planning and dose reduction

Characterization of noise sources in nuclear power reactors

International Nuclear Information System (INIS)

Andhill, Gustav

2004-03-01

Algorithms for unfolding noise sources in nuclear power reactors are investigated. No preliminary knowledge of the functional form of the space dependence is assumed in contrast to the usual methods. The advantage of this is that the algorithms can be applied to various noise sources and the results can be interpreted without expert knowledge. The results can therefore be directly displayed to the plant operators. The precision will however be lower than that of the traditional methods because of the arbitrariness in the type of the noise source. Two different reactor models are studied. First a simple one-dimensional and homogeneous core is considered. Three methods for finding the noise source from the measured flux noise are investigated here. The first one is based on the inversion of an appropriate pre-calculated noise source-to-measured induced neutron noise transfer function. The second one relies on the use of the measured neutron noise as the solution of the equations giving the neutron noise induced by a given noise source. The advantage of this second method is that the noise source can be determined directly, i.e., without any Inversion of a transfer function. The second method is thus called the direct method. The last method is based on a reconstruction of the noise source by spatial Fourier expansion. The two latter techniques are found usable for different locations of the actual noise source in the 1D core. They are therefore tried on more sophisticated two-dimensional models of cores. The direct method is able both to determine the nature of the noise source and its location in 2D

Characterization of noise sources in nuclear power reactors

Energy Technology Data Exchange (ETDEWEB)

Andhill, Gustav

2004-03-01

Algorithms for unfolding noise sources in nuclear power reactors are investigated. No preliminary knowledge of the functional form of the space dependence is assumed in contrast to the usual methods. The advantage of this is that the algorithms can be applied to various noise sources and the results can be interpreted without expert knowledge. The results can therefore be directly displayed to the plant operators. The precision will however be lower than that of the traditional methods because of the arbitrariness in the type of the noise source. Two different reactor models are studied. First a simple one-dimensional and homogeneous core is considered. Three methods for finding the noise source from the measured flux noise are investigated here. The first one is based on the inversion of an appropriate pre-calculated noise source-to-measured induced neutron noise transfer function. The second one relies on the use of the measured neutron noise as the solution of the equations giving the neutron noise induced by a given noise source. The advantage of this second method is that the noise source can be determined directly, i.e., without any Inversion of a transfer function. The second method is thus called the direct method. The last method is based on a reconstruction of the noise source by spatial Fourier expansion. The two latter techniques are found usable for different locations of the actual noise source in the 1D core. They are therefore tried on more sophisticated two-dimensional models of cores. The direct method is able both to determine the nature of the noise source and its location in 2D.

Identification and characterization of fine and coarse particulate matter sources in a middle-European urban environment

International Nuclear Information System (INIS)

Kertesz, Zs.; Szoboszlai, Z.; Angyal, A.; Dobos, E.; Borbely-Kiss, I.

2010-01-01

In this work a source apportionment study is presented which aimed to characterize the PM 2.5 and PM 2.5-10 sources in the urban area of Debrecen, East-Hungary by using streaker samples, IBA methods and positive matrix factorization (PMF) analysis. Samples of fine (PM 2.5 ) and coarse (PM 2.5-10 ) urban particulate matter were collected with 2 h time resolution in the frame of five sampling campaigns during 2007-2009 in different seasons in the downtown of Debrecen. Elemental concentrations from Al to Pb of over 1000 samples were obtained by particle induced X-ray emission (PIXE); concentrations of black carbon (BC) were determined with a smoke stain reflectometer. On this data base source apportionment was carried out by using the PMF method. Seven factors were identified for both size fractions, including soil dust, traffic, secondary aerosol - sulphates, domestic heating, oil combustion, agriculture and an unknown factor enriched with chlorine. Seasonal and daily variation of the different factors was studied as well as their dependence on meteorological parameters. Besides determining the time patterns characteristic to the city, several emission episodes were identified including a Saharan dust intrusion on 21st-24th May, 2008.

Source identification of ambient PM2.5 during summer inhalation exposure studies in Detroit, MI

Energy Technology Data Exchange (ETDEWEB)

Morishita, M.; Keeler, G.J.; Wagner, J.G.; Harkema, J.R. [University of Michigan, Ann Arbor, MI (United States). Air Quality Laboratory

2006-07-15

Particulate air pollution is associated with cardiopulmonary morbidity and mortality in heavily populated urban centers of the United States. Because ambient fine particulate matter (aerodynamic diameter {<=} 2.5 {mu}m; PM2.5) is a complex mixture resulting from multiple sources and variable atmospheric conditions, it is difficult to identify specific components of PM2.5 that are responsible for adverse health effects. During four consecutive summers from 2000 to 2003 we characterized the ambient gaseous and PM2.5 air quality in an urban southwest Detroit community where childhood asthma hospitalization rates are more than twice the statewide average. Both integrated and continuous PM measurements together with gaseous air pollution measurements were performed using a mobile air research facility, AirCARE1, in which concurrent toxicological studies were being conducted. Chemical and physical characterizations of PM2.5 as well as receptor modeling using positive matrix factorization (PMF) were completed. Results from PMF indicated that six major sources contributed to the observed ambient PM2.5 mass during the summer months. Primary sources included (1) coal combustion/secondary sulfate aerosol, (2) motor vehicle/urban road dust, (3) municipal waste incinerators, (4) oil combustion/refineries, (5) sewage sludge incinerators, and (6) iron/steel manufacturing. Although the contribution of the coal/secondary sulfate aerosol source was greater than other factors, increased levels of urban PM2.5 from local combustion sources were also observed. In addition to characterization of ambient PM2.5 and their sources in southwest Detroit, this paper discusses possible associations of ambient PM2.5 from local combustion sources, specifically incinerator and refinery emissions and the observed adverse health effects during the inhalation exposure campaigns.

A Study on Improvement of Algorithm for Source Term Evaluation

International Nuclear Information System (INIS)

Park, Jeong Ho; Park, Do Hyung; Lee, Jae Hee

2010-03-01

The program developed by KAERI for source term assessment of radwastes from the advanced nuclear fuel cycle consists of spent fuel database analysis module, spent fuel arising projection module, and automatic characterization module for radwastes from pyroprocess. To improve the algorithm adopted the developed program, following items were carried out: - development of an algorithm to decrease analysis time for spent fuel database - development of setup routine for a analysis procedure - improvement of interface for spent fuel arising projection module - optimization of data management algorithm needed for massive calculation to estimate source terms of radwastes from advanced fuel cycle The program developed through this study has a capability to perform source term estimation although several spent fuel assemblies with different fuel design, initial enrichment, irradiation history, discharge burnup, and cooling time are processed at the same time in the pyroprocess. It is expected that this program will be very useful for the design of unit process of pyroprocess and disposal system

A measurement-based X-ray source model characterization for CT dosimetry computations.

Science.gov (United States)

Sommerville, Mitchell; Poirier, Yannick; Tambasco, Mauro

2015-11-08

The purpose of this study was to show that the nominal peak tube voltage potential (kVp) and measured half-value layer (HVL) can be used to generate energy spectra and fluence profiles for characterizing a computed tomography (CT) X-ray source, and to validate the source model and an in-house kV X-ray dose computation algorithm (kVDoseCalc) for computing machine- and patient-specific CT dose. Spatial variation of the X-ray source spectra of a Philips Brilliance and a GE Optima Big Bore CT scanner were found by measuring the HVL along the direction of the internal bow-tie filter axes. Third-party software, Spektr, and the nominal kVp settings were used to generate the energy spectra. Beam fluence was calculated by dividing the integral product of the spectra and the in-air NIST mass-energy attenuation coefficients by in-air dose measurements along the filter axis. The authors found the optimal number of photons to seed in kVDoseCalc to achieve dose convergence. The Philips Brilliance beams were modeled for 90, 120, and 140 kVp tube settings. The GE Optima beams were modeled for 80, 100, 120, and 140 kVp tube settings. Relative doses measured using a Capintec Farmer-type ionization chamber (0.65 cc) placed in a cylindrical polymethyl methacrylate (PMMA) phantom and irradiated by the Philips Brilliance, were compared to those computed with kVDoseCalc. Relative doses in an anthropomorphic thorax phantom (E2E SBRT Phantom) irradiated by the GE Optima were measured using a (0.015 cc) PTW Freiburg ionization chamber and compared to computations from kVDoseCalc. The number of photons required to reduce the average statistical uncertainty in dose to measurement over all 12 PMMA phantom positions was found to be 1.44%, 1.47%, and 1.41% for 90, 120, and 140 kVp, respectively. The maximum percent difference between calculation and measurement for all energies, measurement positions, and phantoms was less than 3.50%. Thirty-five out of a total of 36 simulation conditions were

Characterization of sildenafil citrate tablets of different sources by near infrared chemical imaging and chemometric tools.

Science.gov (United States)

Sabin, Guilherme P; Lozano, Valeria A; Rocha, Werickson F C; Romão, Wanderson; Ortiz, Rafael S; Poppi, Ronei J

2013-11-01

The chemical imaging technique by near infrared spectroscopy was applied for characterization of formulations in tablets of sildenafil citrate of six different sources. Five formulations were provided by Brazilian Federal Police and correspond to several trademarks of prohibited marketing and one was an authentic sample of Viagra. In a first step of the study, multivariate curve resolution was properly chosen for the estimation of the distribution map of concentration of the active ingredient in tablets of different sources, where the chemical composition of all excipients constituents was not truly known. In such cases, it is very difficult to establish an appropriate calibration technique, so that only the information of sildenafil is considered independently of the excipients. This determination was possible only by reaching the second-order advantage, where the analyte quantification can be performed in the presence of unknown interferences. In a second step, the normalized histograms of images from active ingredient were grouped according to their similarities by hierarchical cluster analysis. Finally it was possible to recognize the patterns of distribution maps of concentration of sildenafil citrate, distinguishing the true formulation of Viagra. This concept can be used to improve the knowledge of industrial products and processes, as well as, for characterization of counterfeit drugs. Copyright © 2013. Published by Elsevier B.V.

Characterization of a novel x-ray source: The MIRRORCLE-6X system

International Nuclear Information System (INIS)

Gambaccini, M.; Marziani, M.; Taibi, A.; Cardarelli, P.; Di Domenico, G.; Mastella, E.

2012-01-01

MIRRORCLE is a tabletop synchrotron light source being investigated within an EC funded project named LABSYNC. To evaluate the potential of this novel x-ray source for medical imaging applications, a set of measurements was performed at the MIRRORCLE factory in Japan. In particular, the aim of this work was to characterize the proposed compact x-ray source by determining different parameters, such as the intensity of the broad spectra produced with thin wire targets, the size of the focal spot and its distribution. The average electron-beam impact current on wire targets was calculated by several methods and it was demonstrated to be in the range 0.5-1.0μA. By comparing these values with data available for conventional x-ray tubes, the current needed to achieve the same fluence as in a standard diagnostic examination was estimated to be about 0.1-0.5 mA. Finally, results from the measurements of the electron-beam impact cross-section on the target suggested that the diameter of the electron beam circulating in the storage ring is about 6 mm.

Assessment of Laser-Driven Pulsed Neutron Sources for Poolside Neutron-based Advanced NDE – A Pathway to LANSCE-like Characterization at INL

Energy Technology Data Exchange (ETDEWEB)

Roth, Markus [Technische Univ. Darmstadt (Germany); Vogel, Sven C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bourke, Mark Andrew M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fernandez, Juan Carlos [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mocko, Michael Jeffrey [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Glenzer, Siegfried [Stanford Univ., CA (United States); Leemans, Wim [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Siders, Craig [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Haefner, Constantin [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

2017-04-19

A variety of opportunities for characterization of fresh nuclear fuels using thermal (~25meV) and epithermal (~10eV) neutrons have been documented at Los Alamos National Laboratory. They include spatially resolved non-destructive characterization of features, isotopic enrichment, chemical heterogeneity and stoichiometry. The LANSCE spallation neutron source is well suited in neutron fluence and temporal characteristics for studies of fuels. However, recent advances in high power short pulse lasers suggest that compact neutron sources might, over the next decade, become viable at a price point that would permit their consideration for poolside characterization on site at irradiation facilities. In a laser-driven neutron source the laser is used to accelerate deuterium ions into a beryllium target where neutrons are produced. At this time, the technology is new and their total neutron production is approximately four orders of magnitude less than a facility like LANSCE. However, recent measurements on a sub-optimized system demonstrated >10¹⁰ neutrons in sub-nanosecond pulses in predominantly forward direction. The compactness of the target system compared to a spallation target may allow exchanging the target during a measurement to e.g. characterize a highly radioactive sample with thermal, epithermal, and fast neutrons as well as hard X-rays, thus avoiding sample handling. At this time several groups are working on laser-driven neutron production and are advancing concepts for lasers, laser targets, and optimized neutron target/moderator systems. Advances in performance sufficient to enable poolside fuels characterization with LANSCE-like fluence on sample within a decade may be possible. This report describes the underlying physics and state-of-the-art of the laser-driven neutron production process from the perspective of the DOE/NE mission. It also discusses the development and understanding that will be necessary to provide customized capability for

Experimental characterization and Monte Carlo simulation of Si(Li) detector efficiency by radioactive sources and PIXE

Energy Technology Data Exchange (ETDEWEB)

Mesradi, M. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France); Elanique, A. [Departement de Physique, FS/BP 8106, Universite Ibn Zohr, Agadir, Maroc (Morocco); Nourreddine, A. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)], E-mail: abdelmjid.nourreddine@ires.in2p3.fr; Pape, A.; Raiser, D.; Sellam, A. [Institut Pluridisciplinaire Hubert-Curien, UMR 7178 CNRS/IN2P3 et Universite Louis Pasteur, 23 rue du Loess, BP 28, F-67037 Strasbourg Cedex 2 (France)

2008-06-15

This work relates to the study and characterization of the response function of an X-ray spectrometry system. The intrinsic efficiency of a Si(Li) detector has been simulated with the Monte Carlo codes MCNP and GEANT4 in the photon energy range of 2.6-59.5 keV. After finding it necessary to take a radiograph of the detector inside its cryostat to learn the correct dimensions, agreement within 10% between the simulations and experimental measurements with several point-like sources and PIXE results was obtained.

Characterization of an ion beam produced by extraction and acceleration of ions from a wire plasma source

International Nuclear Information System (INIS)

Gueroult, R.

2011-09-01

In this study we first model a DC low pressure wire plasma source and then characterize the properties of an ion gun derived from the plasma source. In order to study the properties of the derived ion gun, we develop a particle-in-cell code fitted to the modelling of the wire plasma source operation, and validate it by confrontation with the results of an experimental study. In light of the simulation results, an analysis of the wire discharge in terms of a collisional Child-Langmuir ion flow in cylindrical geometry is proposed. We interpret the mode transition as a natural reorganization of the discharge when the current is increased above a threshold value which is a function of the discharge voltage, the pressure and the inter-electrodes distance. In addition, the analysis of the energy distribution function of ions impacting the cathode demonstrates the ability to extract an ion beam of low energy spread around the discharge voltage assuming that the discharge is operated in its high pressure mode. An ion source prototype allowing the extraction and acceleration of ions from the wire source is then proposed. The experimental study of such a device confirms that, apart from a shift corresponding to the accelerating voltage, the acceleration scheme does not spread the ion velocity distribution function along the axis of the beam. It is therefore possible to produce tunable energy (0 - 5 keV) ion beams of various ionic species presenting limited energy dispersion (∼ 10 eV). The typical beam currents are about a few tens of micro-amperes, and the divergence of such a beam is on the order of one degree. A numerical modelling of the ion source is eventually conducted in order to identify potential optimizations of the concept. (author)

Progress in characterizing the multidimensional color quality properties of white LED light sources

Science.gov (United States)

Teunissen, Kees; Hoelen, Christoph

2016-03-01

With the introduction of solid state light sources, the variety in emission spectra is almost unlimited. However, the set of standardized parameters to characterize a white LED light source, such as correlated color temperature (CCT) and CIE general color rendering index (Ra), is known to be limited and insufficient for describing perceived differences between light sources. Several characterization methods have been proposed over the past decades, but their contribution to perceived color quality has not always been validated. To gain more insight in the relevant characteristics of the emission spectra for specific applications, we have conducted a perception experiment to rate the attractiveness of three sets of objects, including fresh food, packaging materials and skin tones. The objects were illuminated with seven different combinations of Red, Green, Blue, Amber and White LEDs, all with the same CCT and illumination level, but with differences in Ra and color saturation. The results show that, in general, object attractiveness does not correlate well with Ra, but shows a positive correlation with saturation increase for two out of three applications. There is no clear relation between saturation and skin tone attractiveness, partly due to differences in preference between males and females. A relative gamut area index (Ga) represents the average change in saturation and a complementary color vector graphic shows the direction and magnitude of chromatic differences for the eight CIE-1974 test-color samples. Together with the CIE general color rendering index (Ra) they provide useful information for designing and optimizing application specific emission spectra.

Seismic Hazard characterization study using an earthquake source with Probabilistic Seismic Hazard Analysis (PSHA) method in the Northern of Sumatra

International Nuclear Information System (INIS)

Yahya, A.; Palupi, M. I. R.; Suharsono

2016-01-01

Sumatra region is one of the earthquake-prone areas in Indonesia because it is lie on an active tectonic zone. In 2004 there is earthquake with a moment magnitude of 9.2 located on the coast with the distance 160 km in the west of Nanggroe Aceh Darussalam and triggering a tsunami. These events take a lot of casualties and material losses, especially in the Province of Nanggroe Aceh Darussalam and North Sumatra. To minimize the impact of the earthquake disaster, a fundamental assessment of the earthquake hazard in the region is needed. Stages of research include the study of literature, collection and processing of seismic data, seismic source characterization and analysis of earthquake hazard by probabilistic methods (PSHA) used earthquake catalog from 1907 through 2014. The earthquake hazard represented by the value of Peak Ground Acceleration (PGA) and Spectral Acceleration (SA) in the period of 0.2 and 1 second on bedrock that is presented in the form of a map with a return period of 2475 years and the earthquake hazard curves for the city of Medan and Banda Aceh. (paper)

Characterization of selenium in ambient aerosols and primary emission sources.

Science.gov (United States)

De Santiago, Arlette; Longo, Amelia F; Ingall, Ellery D; Diaz, Julia M; King, Laura E; Lai, Barry; Weber, Rodney J; Russell, Armistead G; Oakes, Michelle

2014-08-19

Atmospheric selenium (Se) in aerosols was investigated using X-ray absorption near-edge structure (XANES) spectroscopy and X-ray fluorescence (XRF) microscopy. These techniques were used to determine the oxidation state and elemental associations of Se in common primary emission sources and ambient aerosols collected from the greater Atlanta area. In the majority of ambient aerosol and primary emission source samples, the spectroscopic patterns as well as the absence of elemental correlations suggest Se is in an elemental, organic, or oxide form. XRF microscopy revealed numerous Se-rich particles, or hotspots, accounting on average for ∼16% of the total Se in ambient aerosols. Hotspots contained primarily Se(0)/Se(-II). However, larger, bulk spectroscopic characterizations revealed Se(IV) as the dominant oxidation state in ambient aerosol, followed by Se(0)/Se(-II) and Se(VI). Se(IV) was the only observed oxidation state in gasoline, diesel, and coal fly ash, while biomass burning contained a combination of Se(0)/Se(-II) and Se(IV). Although the majority of Se in aerosols was in the most toxic form, the Se concentration is well below the California Environmental Protection Agency chronic exposure limit (∼20000 ng/m(3)).

Characterization of continuous and pulsed emission modes of a hybrid micro focus x-ray source for medical imaging applications

International Nuclear Information System (INIS)

Ghani, Muhammad U.; Wong, Molly D.; Ren, Liqiang; Wu, Di; Zheng, Bin; Rong, John X.; Wu, Xizeng; Liu, Hong

2017-01-01

The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16 µm to 50 µm as the source output power changes from 10 to 39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (µA) and distances. The beam quality was measured in terms of half value layer (HVL), kV accuracy was measured with a non-invasive kV meter, and the spectra was measured using a compact integrated spectrometer system. The focal spot sizes were measured using a slit method with a CCD detector with a pixel pitch of 22 µm. The spatial resolution was quantitatively measured using the slit method with a CMOS flat panel detector with a 50 µm pixel pitch, and compared to the qualitative results obtained by imaging a contrast bar pattern. The focal spot sizes in the vertical direction were smaller than that of the horizontal direction, the impact of which was visible when comparing the spatial resolution values. Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution effects. There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications. - Highlights: • A micro focus x-ray source that operates in both continuous and pulse emission modes was quantitatively characterized. • The source output, beam quality, focal spot measurements, kV accuracy, spectra analyses and spatial resolution were measured. • Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam

Characterization of continuous and pulsed emission modes of a hybrid micro focus x-ray source for medical imaging applications

Energy Technology Data Exchange (ETDEWEB)

Ghani, Muhammad U.; Wong, Molly D.; Ren, Liqiang; Wu, Di; Zheng, Bin [Center for Biomedical Engineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019 (United States); Rong, John X. [Department of Imaging Physics, University of Texas MD Anderson Cancer Center, Houston, TX 77030 (United States); Wu, Xizeng [Department of Radiology, University of Alabama at Birmingham, Birmingham, AL 35249 (United States); Liu, Hong, E-mail: liu@ou.edu [Center for Biomedical Engineering and School of Electrical and Computer Engineering, University of Oklahoma, Norman, OK 73019 (United States)

2017-05-01

The aim of this study was to quantitatively characterize a micro focus x-ray tube that can operate in both continuous and pulsed emission modes. The micro focus x-ray source (Model L9181-06, Hamamatsu Photonics, Japan) has a varying focal spot size ranging from 16 µm to 50 µm as the source output power changes from 10 to 39 W. We measured the source output, beam quality, focal spot sizes, kV accuracy, spectra shapes and spatial resolution. Source output was measured using an ionization chamber for various tube voltages (kVs) with varying current (µA) and distances. The beam quality was measured in terms of half value layer (HVL), kV accuracy was measured with a non-invasive kV meter, and the spectra was measured using a compact integrated spectrometer system. The focal spot sizes were measured using a slit method with a CCD detector with a pixel pitch of 22 µm. The spatial resolution was quantitatively measured using the slit method with a CMOS flat panel detector with a 50 µm pixel pitch, and compared to the qualitative results obtained by imaging a contrast bar pattern. The focal spot sizes in the vertical direction were smaller than that of the horizontal direction, the impact of which was visible when comparing the spatial resolution values. Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam quality, spectra shape and spatial resolution effects. There were no significantly large differences, thus providing the motivation for future studies to design and develop stable and robust cone beam imaging systems for various diagnostic applications. - Highlights: • A micro focus x-ray source that operates in both continuous and pulse emission modes was quantitatively characterized. • The source output, beam quality, focal spot measurements, kV accuracy, spectra analyses and spatial resolution were measured. • Our analyses revealed that both emission modes yield comparable imaging performances in terms of beam

Performance evaluation of a permanent ring magnet based helicon plasma source for negative ion source research

Science.gov (United States)

Pandey, Arun; Bandyopadhyay, M.; Sudhir, Dass; Chakraborty, A.

2017-10-01

Helicon wave heated plasmas are much more efficient in terms of ionization per unit power consumed. A permanent magnet based compact helicon wave heated plasma source is developed in the Institute for Plasma Research, after carefully optimizing the geometry, the frequency of the RF power, and the magnetic field conditions. The HELicon Experiment for Negative ion-I source is the single driver helicon plasma source that is being studied for the development of a large sized, multi-driver negative hydrogen ion source. In this paper, the details about the single driver machine and the results from the characterization of the device are presented. A parametric study at different pressures and magnetic field values using a 13.56 MHz RF source has been carried out in argon plasma, as an initial step towards source characterization. A theoretical model is also presented for the particle and power balance in the plasma. The ambipolar diffusion process taking place in a magnetized helicon plasma is also discussed.

Surface characterization of III-V MOCVD films from heterocyclic single-source precursors; Oberflaechencharakterisierung von III-V MOCVD-Filmen aus heterozyklischen Single Source Precursoren

Energy Technology Data Exchange (ETDEWEB)

Seemayer, Andreas

2009-07-13

In the present thesis the sublimation and evaporation properties of heterocyclic gallium and antimony containing single-source precursors as well as the chemical composition and morphology of the films fabricated from this were studied. The single-source precursors available by a new synthesis route were characterized concerning their evaporation properties and the obtained films studied surface-physically. By this way the process parameters were optimized and the applicability of the single-source precursors in HV-MOCVD processes studied. By evaporation experiments in the UHV it could be shown that thereby lighter ligands like ethyl- and methyl-groups lead to a lower contamination of the reaction space with carbon containing molecules. Furthermore it was expected that the 6-rings synthetized with short ligands exhibit a high stability. This however could not be confirmed. By unwanted parasitary reactions in the gaseous phase respectively dissociative sublimation in the gaseous phase a deposition of GaSb with these precursors was not possible. The 4-ring stabilized with tertiary-butyl and ethyl-groups caused in the evaporation the largest contamination of the gaseous phase, becauselonger-chain hydrocarbons exhibil only a bad pump cross section. By parasitary reactions originating elementary antimony is detectable in the gaseous phase. The films were studied concerning their chemical composition and their transport- respectively storage-conditioned surface contamination. Furthermore it has become clear that not only a purely synthetized precursor substance but also the reactor design is deciding for a successful deposition and a high film quality. First by successive optimization of the evaporation geometry it was possible to reduce the roughness of the produced GaSb films down to about 10 nm-30 nm.

Production and characterization of cellulolytic enzymes from Trichoderma reesei grown on various carbon sources

Energy Technology Data Exchange (ETDEWEB)

Warzywoda, Michel; Labre, Elisabeth; Pourquie, Jacques [Institut Francais du Petrole (IFP), 92 - Rueil-Malmaison (France)

1992-01-01

Ethanol production from lignocellulosics is considered, using a process in which biomass is first pretreated by steam explosion, yielding freely water-extractible pentoses and a cellulose-rich residue which can be further hydrolyzed by cellulases into glucose to be fermented into ethanol. Results that are reported show that both the pentose extracts and the glucose-rich hydrolyzates can be used as carbon sources for cellulase production by Trichoderma reesei. When compared with lactose as the main carbon source, pentose extracts support lower but satisfactory protein productions which are characterized by an increase in hemicellulolytic activities, which significantly improves the saccharifying potential of these enzyme preparations. (author).

Geochemical characterization of critical dust source regions in the American West

Science.gov (United States)

Aarons, Sarah M.; Blakowski, Molly A.; Aciego, Sarah M.; Stevenson, Emily I.; Sims, Kenneth W. W.; Scott, Sean R.; Aarons, Charles

2017-10-01

The generation, transport, and deposition of mineral dust are detectable in paleoclimate records from land, ocean, and ice, providing valuable insight into earth surface conditions and cycles on a range of timescales. Dust deposited in marine and terrestrial ecosystems can provide critical nutrients to nutrient-limited ecosystems, and variations in dust provenance can indicate changes in dust production, sources and transport pathways as a function of climate variability and land use change. Thus, temporal changes in locations of dust source areas and transport pathways have implications for understanding interactions between mineral dust, global climate, and biogeochemical cycles. This work characterizes dust from areas in the American West known for dust events and/or affected by increasing human settlement and livestock grazing during the last 150 years. Dust generation and uplift from these dust source areas depends on climate and land use practices, and the relative contribution of dust has likely changed since the expansion of industrialization and agriculture into the western United States. We present elemental and isotopic analysis of 28 potential dust source area samples analyzed using Thermal Ionization Mass Spectrometry (TIMS) for 87Sr/86Sr and 143Nd/144Nd composition and Multi-Collector Inductively Coupled Plasma Mass Spectrometer (MC-ICPMS) for 176Hf/177Hf composition, and ICPMS for major and trace element concentrations. We find significant variability in the Sr, Nd, and Hf isotope compositions of potential source areas of dust throughout western North America, ranging from 87Sr/86Sr = 0.703699 to 0.740236, εNd = -26.6 to 2.4, and εHf = -21.7 to -0.1. We also report differences in the trace metal and phosphorus concentrations in the geologic provinces sampled. This research provides an important resource for the geochemical tracing of dust sources and sinks in western North America, and will aid in modeling the biogeochemical impacts of increased

Characterization and indentification of air pollution sources in Metro Manila

International Nuclear Information System (INIS)

Santos, Flora L.; Pabroa, Preciosa Corazon B.; Racho, Joseph Michael D.; Morco, Ryan P.; Bautista VII, Angel T.; Bucal, Camille Grace D.

2010-01-01

Air particulates matter (PM 1 0 and PM 2 .5) is a mixture of different pollutant sources which can be of anthropogenic and/or natural origin. Identification and apportionment of pollutant sources is important to be able to have better understanding of prevailing conditions in the area and thus better air quality management can be applied. Results have shown that in all the sampling sites, a major fraction of pollutant sources come from vehicular or traffic-oriented sources, comprising more than 30% of PM 2 .5. Of particular great concern especially in the residents of the area are the high Pb levels in Valenzuela City. In 2005, the annual mean level of PM 1 0 Pb in Valenzuela was 0.267 μg/m 3 while the other PNRI sampling sites registered annual mean levels between 0033 to 0.085 μ/m 3 . The high Pb condition is reflected in the source apportionment studies with Pb sources showing up in both the coarse (PM 1 0-2.5) and the fine fractions (PM 2 .5). The CPF analysis plots of 2008 Pb levels in both the coarse and the fine fractions show patterns for probable sources in 2008. Further study of the location of battery recycling facilities and other possible sources of lead is needed to validate the results of the CPF determination. (author)

Synthesis of second phase hybrid ceramics using two different bio-source and a comparative study on their morphological characterization

Science.gov (United States)

Karivaratharajan, Adhitya; Baskaran, Sidharth; Thillairajan, K.

2018-02-01

Ceramics are generally synthesized with various sources and methods. The most common method for synthesis of ceramics with reduced cost and energy is SOL-GEL method. Combustion synthesis is also a most widely used method for ceramic synthesis. In general, ceramics have enhanced hardness and dimensional stability even at elevated temperatures. For this reason, they are used in the production of refractories, thermal barrier coatings, chemical resistant coatings, wear resistant coatings, and also as reinforcement material to produce metal matrix composites and polymer matrix composites. This work concentrates on the comparison of morphological characterization of such reinforcement particles synthesized from different sources. The particles size range varying from 7 μm to 250 μm with flaky and spongy structures are observed in the ash of Vicia faba. However, the ash of Cocos nucífera resulted in fibrous structure with a diameter of 50 μm to length above 600 μm, particles size ranging from 10 μm to 70 μm micro tubes of diameter 3.6 μm to length of 150 μm. The EDX and XRD analysis of Vicia faba showed the presence of carbon as the major element with a few other elements.

Characterize kinematic rupture history of large earthquakes with Multiple Haskell sources

Science.gov (United States)

Jia, Z.; Zhan, Z.

2017-12-01

Earthquakes are often regarded as continuous rupture along a single fault, but the occurrence of complex large events involving multiple faults and dynamic triggering challenges this view. Such rupture complexities cause difficulties in existing finite fault inversion algorithms, because they rely on specific parameterizations and regularizations to obtain physically meaningful solutions. Furthermore, it is difficult to assess reliability and uncertainty of obtained rupture models. Here we develop a Multi-Haskell Source (MHS) method to estimate rupture process of large earthquakes as a series of sub-events of varying location, timing and directivity. Each sub-event is characterized by a Haskell rupture model with uniform dislocation and constant unilateral rupture velocity. This flexible yet simple source parameterization allows us to constrain first-order rupture complexity of large earthquakes robustly. Additionally, relatively few parameters in the inverse problem yields improved uncertainty analysis based on Markov chain Monte Carlo sampling in a Bayesian framework. Synthetic tests and application of MHS method on real earthquakes show that our method can capture major features of large earthquake rupture process, and provide information for more detailed rupture history analysis.

Development and characterization of a laser-based hard x-ray source

International Nuclear Information System (INIS)

Tillman, C.

1996-11-01

A laser-produced plasma was generated by focusing 100 fs laser pulses, with an energy of 150 mJ, onto metal targets. The laser intensity was expected to reach 10 17 W/cm -2 . Radiation was emitted from the created plasma, with photon energies up to the MeV region. The laser-based X-ray source was optimized, with the purpose of making it a realistic source of hard X-rays (>10 keV). Dedicated equipment was developed for efficient generation and utilization of the hard X-rays. The X-ray source was characterized with respect to its spatial extent and the X-ray yield. Measurements were made of the spectral distribution, by the use of single-photon-counting detectors in different geometries, crystal spectrometers and dose measurements in combination with absorption filters. Ablation of the target material in the laser produced plasma was investigated. Imaging applications have been demonstrated, including ultrafast (picosecond) X-ray imaging, magnification imaging of up to x80, differential imaging in the spectral domain, and imaging of various biological and technical objects. The biological response of ultra-intense X-ray pulses was assessed in cell-culture exposures. The results indicate that the biological response from ultra-intense X-ray exposures is similar to the response with conventional X-ray tubes. 82 refs., 14 figs

Development and characterization of a laser-based hard x-ray source

Energy Technology Data Exchange (ETDEWEB)

Tillman, C.

1996-11-01

A laser-produced plasma was generated by focusing 100 fs laser pulses, with an energy of 150 mJ, onto metal targets. The laser intensity was expected to reach 10{sup 17} W/cm{sup -2}. Radiation was emitted from the created plasma, with photon energies up to the MeV region. The laser-based X-ray source was optimized, with the purpose of making it a realistic source of hard X-rays (>10 keV). Dedicated equipment was developed for efficient generation and utilization of the hard X-rays. The X-ray source was characterized with respect to its spatial extent and the X-ray yield. Measurements were made of the spectral distribution, by the use of single-photon-counting detectors in different geometries, crystal spectrometers and dose measurements in combination with absorption filters. Ablation of the target material in the laser produced plasma was investigated. Imaging applications have been demonstrated, including ultrafast (picosecond) X-ray imaging, magnification imaging of up to x80, differential imaging in the spectral domain, and imaging of various biological and technical objects. The biological response of ultra-intense X-ray pulses was assessed in cell-culture exposures. The results indicate that the biological response from ultra-intense X-ray exposures is similar to the response with conventional X-ray tubes. 82 refs., 14 figs.

Genetic characterization of Arcobacter isolates from various sources.

Science.gov (United States)

Shah, A H; Saleha, A A; Zunita, Z; Cheah, Y K; Murugaiyah, M; Korejo, N A

2012-12-07

Arcobacter is getting more attention due to its detection from wide host-range and foods of animal origin. The objective of this study was to determine the prevalence of Arcobacter spp. in various sources at farm level and beef retailed in markets in Malaysia and to assess the genetic relatedness among them. A total of 273 samples from dairy cattle including cattle (n=120), floor (n=30), water (n=18) and milk (n=105) as well as 148 beef samples collected from retail markets were studied. The overall prevalence of Arcobacter in various sources was 15% (63/421). However, source-wise detection rate of Arcobacter spp. was recorded as 26.66% (8/30) in floor, 26.3% (39/148) in beef, 11.11% (2/18) in water, 7.6% (8/105) in milk and 6.66% (8/120) in cattle. Arcobacter butzleri was the frequently isolated species however, a total of 75%, 66.7%, 53.8%, 50% and 12.5%% samples from floor, milk, beef, water and cattle, respectively, were carrying more than one species simultaneously. One (12.5%) cattle and beef sample (2.5%) found to be carrying one Arcobacter spp., A. skirrowii, only. Typing of Arcobacter isolates was done though pulsed field gel electrophoresis (PFGE) after digested with Eag1 restriction endonuclease (RE). Digestion of genomic DNA of Arcobacter from various sources yielded 12 major clusters (≥ 50% similarity) which included 29 different band patterns. A number of closely related A. butzleri isolates were found from beef samples which indicate cross contamination of common type of Arcobacter. Fecal shedding of Arcobacter by healthy animals can contaminate water and milk which may act as source of infection in humans. Copyright © 2012 Elsevier B.V. All rights reserved.

Earthquake source studies and seismic imaging in Alaska

Science.gov (United States)

Tape, C.; Silwal, V.

2015-12-01

Alaska is one of the world's most seismically and tectonically active regions. Its enhanced seismicity, including slab seismicity down to 180 km, provides opportunities (1) to characterize pervasive crustal faulting and slab deformation through the estimation of moment tensors and (2) to image subsurface structures to help understand the tectonic evolution of Alaska. Most previous studies of earthquakes and seismic imaging in Alaska have emphasized earthquake locations and body-wave travel-time tomography. In the past decade, catalogs of seismic moment tensors have been established, while seismic surface waves, active-source data, and potential field data have been used to improve models of seismic structure. We have developed moment tensor catalogs in the regions of two of the largest sedimentary basins in Alaska: Cook Inlet forearc basin, west of Anchorage, and Nenana basin, west of Fairbanks. Our moment tensor solutions near Nenana basin suggest a transtensional tectonic setting, with the basin developing in a stepover of a left-lateral strike-slip fault system. We explore the effects of seismic wave propagation from point-source and finite-source earthquake models by performing three-dimensional wavefield simulations using seismic velocity models that include major sedimentary basins. We will use our catalog of moment tensors within an adjoint-based, iterative inversion to improve the three-dimensional tomographic model of Alaska.

Evaluation and characterization of General Purpose Heat Source girth welds for the Cassini mission

International Nuclear Information System (INIS)

Lynch, C.M.; Moniz, P.F.; Reimus, M.A.H.

1998-01-01

General Purpose Heat Sources (GPHSs) are components of Radioisotopic thermoelectric Generators (RTGs) which provide electric power for deep space missions. Each GPHS consists of a 238 Pu oxide ceramic pellet encapsulated in a welded iridium alloy shell which forms a protective barrier against the release of plutonia in the unlikely event of a launch-pad failure or reentry incident. GPHS fueled clad girth weld flaw detection was paramount to ensuring this safety function, and was accomplished using both destructive and non-destructive evaluation techniques. The first girth weld produced from each welding campaign was metallographically examined for flaws such as incomplete weld penetration, cracks, or porosity which would render a GPHS unacceptable for flight applications. After an acceptable example weld was produced, the subsequently welded heat sources were evaluated non-destructively for flaws using ultrasonic immersion testing. Selected heat sources which failed ultrasonic testing would be radiographed, and/or, destructively evaluated to further characterize and document anomalous indications. Metallography was also performed on impacted heat sources to determine the condition of the welds

Single particle characterization, source apportionment, and aging effects of ambient aerosols in Southern California

Science.gov (United States)

Shields, Laura Grace

Composed of a mixture of chemical species and phases and existing in a variety of shapes and sizes, atmospheric aerosols are complex and can have serious influence on human health, the environment, and climate. In order to better understand the impact of aerosols on local to global scales, detailed measurements on the physical and chemical properties of ambient particles are essential. In addition, knowing the origin or the source of the aerosols is important for policymakers to implement targeted regulations and effective control strategies to reduce air pollution in their region. One of the most ground breaking techniques in aerosol instrumentation is single particle mass spectrometry (SPMS), which can provide online chemical composition and size information on the individual particle level. The primary focus of this work is to further improve the ability of one specific SPMS technique, aerosol time-of-flight mass spectrometry (ATOFMS), for the use of identifying the specific origin of ambient aerosols, which is known as source apportionment. The ATOFMS source apportionment method utilizes a library of distinct source mass spectral signatures to match the chemical information of the single ambient particles. The unique signatures are obtained in controlled source characterization studies, such as with the exhaust emissions of heavy duty diesel vehicles (HDDV) operating on a dynamometer. The apportionment of ambient aerosols is complicated by the chemical and physical processes an individual particle can undergo as it spends time in the atmosphere, which is referred to as "aging" of the aerosol. Therefore, the performance of the source signature library technique was investigated on the ambient dataset of the highly aged environment of Riverside, California. Additionally, two specific subsets of the Riverside dataset (ultrafine particles and particles containing trace metals), which are known to cause adverse health effects, were probed in greater detail. Finally

MIT modular x-ray source systems for the study of plasma diagnostics

Science.gov (United States)

Coleman, J. W.; Wenzel, K. W.; Petrasso, R. D.; Lo, D. H.; Li, C. K.; Lierzer, J. R.; Wei, T.

1992-10-01

Two new x-ray source systems are now on line at our facility. Each provides an e-beam to 25 kV. Targets are interchangeable between machines, and four x-ray detectors may be used simultaneously with a target. The gridded e-gun of the RACEHORSE system gives a 0.5-1.0-cm pulsable spot on target. The nongridded e-gun of the SCORPION system provides a 0.3-mm or smaller dc microspot on target. RACEHORSE is being used to study and characterize type-II diamond photoconductors for use in diagnosing plasmas, while SCORPION is being used to develop a slitless spectrograph using photographic film. Source design details and some RACEHORSE results are presented.

Molecular Characterization of Yeast Strains Isolated from Different Sources by Restriction Fragment Length Polymorphism

International Nuclear Information System (INIS)

Ali, M. S.; Latif, Z.

2016-01-01

Various molecular techniques like analysis of the amplified rDNA internal transcribed spacers (ITS), intragenic spacers and total ITS region analysis by restriction fragment length polymorphism (RFLP) has been introduced for yeast identification but there are limited databases to identify yeast species on the basis of 5.8S rDNA. In this study, twenty nine yeast strains from various sources including spoiled fruits, vegetables, foodstuffs, and concentrated juices were characterized by PCR-RFLP. PCR-RFLP has been used to characterize yeasts present in different spoiled food samples after isolation of the yeasts. By using this technique, the isolated yeast strains were characterized by direct 5.8S-ITS rDNA region amplification. RFLP analysis was applied to each of the amplification products (varied from 400bp to 800bp) detected, and the corresponding yeast identifications were made according to each specific restriction patterns obtained after treatment with two endonucleases TaqI and HaeIII which yielded a specific banding pattern for each species. For further confirmation amplified products of eleven selected isolates were sequenced and blast on NCBI. Both RFLP and sequence analyses of the strains with accession nos. KF472163, KF472164, KF472165, KF472166, KF472167, KF472168, KF472169, KF472170, KF472171, KF472172, KF472173 gave significantly similar results. The isolates were found to belong five different yeast species including; Candida spp., Pichia spp., Kluyveromyces spp., Clavispora spp. and Hanseniaspora spp. This method provides a fast, easy, reliable and authentic way for determining yeast population present in different type of samples, as compared to traditional characterization technique. (author)

Seismic source zone characterization for the seismic hazard assessment project PEGASOS by the Expert Group 2 (EG1b)

International Nuclear Information System (INIS)

Burkhard, M.; Gruenthal, G.

2009-01-01

A comprehensive study of the seismic hazard related to the four NNP sites in NW Switzerland was performed within the project PEGASOS. To account for the epistemic uncertainties involved in the process of the characterization of seismic source zones in the frame of probabilistic seismic hazard assessments, four different expert teams have developed and defended their models in the frame of an intensive elicitation process. Here, the results of one out of four expert groups are presented. The model of this team is based first of all on considerations regarding the large scale tectonics in the context of the Alpine collision, and neotectonic constraints for defining seismic source zones. This leads to a large scale subdivision based on the structural 'architectural' considerations with little input from the present seismicity. Each of the eight large zones was characterized by the style of present-day faulting, fault orientation, and hypo central depth distribution. A further subdivision of the larger zones is performed based on information provided by the seismicity patterns. 58 small source zones have been defined in this way, each of them characterized by the available tectonic constrains, as well as the pros and cons of different existing geologic views connected to them. Of special concern in this respect were the discussion regarding thin skinned vs. thick skinned tectonics, the tectonic origin of the 1356 Basel earthquake, the role of the Permo-Carboniferous graben structures, and finally the seismogenic orientation of faults with respect to the recent crustal stress field. The uncertainties connected to the delimitations of the small source zones have been handled in form of their regrouping, formalized by the logic tree technique. The maximum magnitudes were estimated as discretized probability distribution functions. After de-clustering the used ECOS earthquake catalogue and an analysis of data completeness as a function of time the parameters of the

Final report of the IAEA advisory group meeting on accelerator-based nuclear analytical techniques for characterization and source identification of aerosol particles

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-07-01

The field of aerosol characterization and source identification covers a wide range of scientific and technical activities in many institutions, in both developed and developing countries. This field includes research and applications on urban air pollution, source apportionment of suspended particulate matter, radioactive aerosol particles, organic compounds carried on particulate matter, elemental characterization of particles, and other areas. The subject of this AGM focused on the use of accelerator-based nuclear analytical techniques for determination of elemental composition of particles (by either bulk or single particle analysis) and the use of accumulated knowledge for source identification.

Final report of the IAEA advisory group meeting on accelerator-based nuclear analytical techniques for characterization and source identification of aerosol particles

International Nuclear Information System (INIS)

1995-01-01

The field of aerosol characterization and source identification covers a wide range of scientific and technical activities in many institutions, in both developed and developing countries. This field includes research and applications on urban air pollution, source apportionment of suspended particulate matter, radioactive aerosol particles, organic compounds carried on particulate matter, elemental characterization of particles, and other areas. The subject of this AGM focused on the use of accelerator-based nuclear analytical techniques for determination of elemental composition of particles (by either bulk or single particle analysis) and the use of accumulated knowledge for source identification

Characterization of a Distributed Plasma Ionization Source (DPIS) for Ion Mobility Spectrometry and Mass Spectrometry

International Nuclear Information System (INIS)

Waltman, Melanie J.; Dwivedi, Prabha; Hill, Herbert; Blanchard, William C.; Ewing, Robert G.

2008-01-01

A recently developed atmospheric pressure ionization source, a distributed plasma ionization source (DPIS), was characterized and compared to commonly used atmospheric pressure ionization sources with both mass spectrometry and ion mobility spectrometry. The source consisted of two electrodes of different sizes separated by a thin dielectric. Application of a high RF voltage across the electrodes generated plasma in air yielding both positive and negative ions depending on the polarity of the applied potential. These reactant ions subsequently ionized the analyte vapors. The reactant ions generated were similar to those created in a conventional point-to-plane corona discharge ion source. The positive reactant ions generated by the source were mass identified as being solvated protons of general formula (H2O)nH+ with (H2O)2H+ as the most abundant reactant ion. The negative reactant ions produced were mass identified primarily as CO3-, NO3-, NO2-, O3- and O2- of various relative intensities. The predominant ion and relative ion ratios varied depending upon source construction and supporting gas flow rates. A few compounds including drugs, explosives and environmental pollutants were selected to evaluate the new ionization source. The source was operated continuously for several months and although deterioration was observed visually, the source continued to produce ions at a rate similar that of the initial conditions. The results indicated that the DPIS may have a longer operating life than a conventional corona discharge.

Characterization of a 137Cs standard source for calibration purposes at CRCN-NE

International Nuclear Information System (INIS)

Oliveira, Mercia L.; Santos, Marcus A.P. dos; Benvides, Clayton A.

2008-01-01

Radiation protection monitoring instruments should be calibrated by accredited calibration laboratories. To offer calibration services, a laboratory must accomplish all requirements established by the national regulatory agency. The Calibration Service of the Centro Regional de Ciencias Nucleares (CRCN-NE), Comissao Nacional de Energia Nuclear, Recife, Brazil, is trying to achieve this accreditation. In the present work, a 137 Cs standard source was characterized following the national and international recommendations and the results are presented. This source is a commercially available single source irradiator model 28-8A, manufactured by J.L. Shepherd and Associates, with initial activity of 444 GBq (05/13/03). To provide different air kerma rates, as required for the calibration of portable radiation monitors, this irradiator have a set of four lead attenuators with different thickness, providing attenuation factors equal to 2, 4, 10 and 100 times (nominally). The performed tests included: size and uniformity of the radiation standard field at calibration reference position, variation of the air kerma rate for different lead attenuators, determination of attenuation factors for each lead attenuator configuration, and determination of the radiation scattering at the calibration reference position. The results showed the usefulness of the 137 Cs standard source for the calibration of radiation protection monitoring detectors. (author)

On Road Study of Colorado Front Range Greenhouse Gases Distribution and Sources

Science.gov (United States)

Petron, G.; Hirsch, A.; Trainer, M. K.; Karion, A.; Kofler, J.; Sweeney, C.; Andrews, A.; Kolodzey, W.; Miller, B. R.; Miller, L.; Montzka, S. A.; Kitzis, D. R.; Patrick, L.; Frost, G. J.; Ryerson, T. B.; Robers, J. M.; Tans, P.

2008-12-01

The Global Monitoring Division and Chemical Sciences Division of the NOAA Earth System Research Laboratory have teamed up over the summer 2008 to experiment with a new measurement strategy to characterize greenhouse gases distribution and sources in the Colorado Front Range. Combining expertise in greenhouse gases measurements and in local to regional scales air quality study intensive campaigns, we have built the 'Hybrid Lab'. A continuous CO2 and CH4 cavity ring down spectroscopic analyzer (Picarro, Inc.), a CO gas-filter correlation instrument (Thermo Environmental, Inc.) and a continuous UV absorption ozone monitor (2B Technologies, Inc., model 202SC) have been installed securely onboard a 2006 Toyota Prius Hybrid vehicle with an inlet bringing in outside air from a few meters above the ground. To better characterize point and distributed sources, air samples were taken with a Portable Flask Package (PFP) for later multiple species analysis in the lab. A GPS unit hooked up to the ozone analyzer and another one installed on the PFP kept track of our location allowing us to map measured concentrations on the driving route using Google Earth. The Hybrid Lab went out for several drives in the vicinity of the NOAA Boulder Atmospheric Observatory (BAO) tall tower located in Erie, CO and covering areas from Boulder, Denver, Longmont, Fort Collins and Greeley. Enhancements in CO2, CO and destruction of ozone mainly reflect emissions from traffic. Methane enhancements however are clearly correlated with nearby point sources (landfill, feedlot, natural gas compressor ...) or with larger scale air masses advected from the NE Colorado, where oil and gas drilling operations are widespread. The multiple species analysis (hydrocarbons, CFCs, HFCs) of the air samples collected along the way bring insightful information about the methane sources at play. We will present results of the analysis and interpretation of the Hybrid Lab Front Range Study and conclude with perspectives

Palynofacies characterization for hydrocarbon source rock ...

Indian Academy of Sciences (India)

source rock potential of the Subathu Formation in the area. Petroleum geologists are well aware of the fact that the dispersed organic matter derived either from marine or non-marine sediments on reach- ing its maturation level over extended period of time contributes as source material for the produc- tion of hydrocarbons.

Characterization techniques for the high-brightness particle beams of the Advanced Photon Source (APS)

International Nuclear Information System (INIS)

Lumpkin, A.H.

1993-01-01

The Advanced Photon Source (APS) will be a third-generation synchrotron radiation (SR) user facility in the hard x-ray regime (10--100 keV). The design objectives for the 7-GeV storage ring include a positron beam natural emittance of 8 x 10 -9 m-rad at an average current of 100 mA. Proposed methods for measuring the transverse and longitudinal profiles will be described. Additionally, a research and development effort using an rf gun as a low-emittance source of electrons for injection into the 200- to 650-MeV linac subsystem is underway. This latter system is projected to produce electron beams with a normalized, rms emittance of ∼2 π mm-mrad at peak currents of near one hundred amps. This interesting characterization problem will also be briefly discussed. The combination of both source types within one laboratory facility will stimulate the development of diagnostic techniques in these parameter spaces

Characterization of Ground Displacement Sources from Variational Bayesian Independent Component Analysis of Space Geodetic Time Series

Science.gov (United States)

Gualandi, Adriano; Serpelloni, Enrico; Elina Belardinelli, Maria; Bonafede, Maurizio; Pezzo, Giuseppe; Tolomei, Cristiano

2015-04-01

, giving a more reliable estimate of them. Here we introduce the vbICA technique and present its application on synthetic data that simulate a GPS network recording ground deformation in a tectonically active region, with synthetic time-series containing interseismic, coseismic, and postseismic deformation, plus seasonal deformation, and white and coloured noise. We study the ability of the algorithm to recover the original (known) sources of deformation, and then apply it to a real scenario: the Emilia seismic sequence (2012, northern Italy), which is an example of seismic sequence occurred in a slowly converging tectonic setting, characterized by several local to regional anthropogenic or natural sources of deformation, mainly subsidence due to fluid withdrawal and sediments compaction. We apply both PCA and vbICA to displacement time-series recorded by continuous GPS and InSAR (Pezzo et al., EGU2015-8950).

Characterization of the Shielded Neutron Source at Triangle Universities Nuclear Laboratory

Science.gov (United States)

Hobson, Chad; Finch, Sean; Howell, Calvin; Malone, Ron; Tornow, Wernew

2016-09-01

In 2015, Triangle Universities Nuclear Laboratory rebuilt its shielded neutron source (SNS) with the goal of improving neutron beam collimation and reducing neutron and gamma-ray backgrounds. Neutrons are produced via the 2H(d,n)3He reaction and then collimated by heavy shielding to form a beam. The SNS has the ability to produce both a rectangular and circular neutron beam through use of two collimators with different beam apertures. Our work characterized both the neutron beam profiles as well as the neutron and gamma-ray backgrounds at various locations around the SNS. This characterization was performed to provide researchers who use the SNS with beam parameters necessary to plan and conduct an experiment. Vertical and horizontal beam profiles were measured at two different distances from the neutron production cell by scanning a small plastic scintillator across the face of the beam at various energies for each collimator. Background neutron and gamma-ray intensities were measured using time-of-flight techniques at 10 MeV and 16 MeV with the rectangular collimator. We present results on the position and size of neutron beam as well as on the structure and magnitude of the backgrounds.

Preparation, physical characterization, and stability of Ferrous-Chitosan microcapsules using different iron sources

Science.gov (United States)

Handayani, Noer Abyor; Luthfansyah, M.; Krisanti, Elsa; Kartohardjono, Sutrasno; Mulia, Kamarza

2017-11-01

Dietary modification, supplementation and food fortification are common strategies to alleviate iron deficiencies. Fortification of food is an effective long-term approach to improve iron status of populations. Fortification by adding iron directly to food will cause sensory problems and decrease its bioavailability. The purpose of iron encapsulation is: (1) to improve iron bioavailability, by preventing oxidation and contact with inhibitors and competitors; and (2) to disguise the rancid aroma and flavor of iron. A microcapsule formulation of two suitable iron compounds (iron II fumarate and iron II gluconate) using chitosan as a biodegradable polymer will be very important. Freeze dryer was also used for completing the iron microencapsulation process. The main objective of the present study was to prepare and characterize the iron-chitosan microcapsules. Physical characterization, i.e. encapsulation efficiency, iron loading capacity, and SEM, were also discussed in this paper. The stability of microencapsulated iron under simulated gastrointestinal conditions was also investigated, as well. Both iron sources were highly encapsulated, ranging from 71.5% to 98.5%. Furthermore, the highest ferrous fumarate and ferrous gluconate loaded were 1.9% and 4.8%, respectively. About 1.04% to 9.17% and 45.17% to 75.19% of Fe II and total Fe, were released in simulated gastric fluid for two hours and in simulated intestinal fluid for six hours, respectively.

Barrow Black Carbon Source and Impact Study Final Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Barrett, Tate

2014-07-01

The goal of the Barrow Black Carbon Source and Impact campaign was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement (ARM) Climate Research Facility site in Barrow, Alaska. The carbonaceous component was characterized by measuring the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the PM, filter-based collections were used, including a medium volume PM_2.5 sampler and a high volume PM₁₀ sampler. Thirty-eight fine PM fractions (PM_2.5) and 49 coarse (PM₁₀) PM fractions were collected at weekly and bi-monthly intervals. The PM_2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM₁₀ sampler used for the Barrow Black Carbon Source and Impact (BBCSI) study used standard Tisch “hi-vol” motors that have a known lifetime of approximately 1 month under constant use; this necessitated monthly maintenance, and it is suggested that, for future deployment in the Arctic, the motors be upgraded to industrial blowers. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric PM samples from Barrow, Alaska, from July 2012 to June 2013. Preliminary analysis of the OC and BC concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer. However, the annual OC concentrations had a very different seasonal pattern with the highest concentrations during the summer, lowest concentrations during the fall, and increased concentrations during the winter and spring (Figure 1).

Noble gas signatures in the Island of Maui, Hawaii: Characterizing groundwater sources in fractured systems

Science.gov (United States)

Niu, Yi; Castro, M. Clara; Hall, Chris M.; Gingerich, Stephen B.; Scholl, Martha A.; Warrier, Rohit B.

2017-01-01

Uneven distribution of rainfall and freshwater scarcity in populated areas in the Island of Maui, Hawaii, renders water resources management a challenge in this complex and ill-defined hydrological system. A previous study in the Galapagos Islands suggests that noble gas temperatures (NGTs) record seasonality in that fractured, rapid infiltration groundwater system rather than the commonly observed mean annual air temperature (MAAT) in sedimentary systems where infiltration is slower thus, providing information on recharge sources and potential flow paths. Here we report noble gas results from the basal aquifer, springs, and rainwater in Maui to explore the potential for noble gases in characterizing this type of complex fractured hydrologic systems. Most samples display a mass-dependent depletion pattern with respect to surface conditions consistent with previous observations both in the Galapagos Islands and Michigan rainwater. Basal aquifer and rainwater noble gas patterns are similar and suggest direct, fast recharge from precipitation to the basal aquifer. In contrast, multiple springs, representative of perched aquifers, display highly variable noble gas concentrations suggesting recharge from a variety of sources. The distinct noble gas patterns for the basal aquifer and springs suggest that basal and perched aquifers are separate entities. Maui rainwater displays high apparent NGTs, incompatible with surface conditions, pointing either to an origin at high altitudes with the presence of ice or an ice-like source of undetermined origin. Overall, noble gas signatures in Maui reflect the source of recharge rather than the expected altitude/temperature relationship commonly observed in sedimentary systems.

Asynchronous Learning Sources in a High-Tech Organization

Science.gov (United States)

Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

2009-01-01

Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

IDENTIFICATION AND CHARACTERIZATION OF FIVE NON- TRADITIONAL SOURCE CATEGORIES: CATASTROPHIC/ACCIDENTAL RELEASES, VEHICLE REPAIR FACILITIES, RECYCLING, PESTICIDE APPLICATION, AND AGRICULTURAL OPERATIONS

Science.gov (United States)

The report gives results of work that is part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plan (SIP) area source methodologies and to deve...

Characterization of the main error sources of chromatic confocal probes for dimensional measurement

International Nuclear Information System (INIS)

Nouira, H; El-Hayek, N; Yuan, X; Anwer, N

2014-01-01

Chromatic confocal probes are increasingly used in high-precision dimensional metrology applications such as roughness, form, thickness and surface profile measurements; however, their measurement behaviour is not well understood and must be characterized at a nanometre level. This paper provides a calibration bench for the characterization of two chromatic confocal probes of 20 and 350 µm travel ranges. The metrology loop that includes the chromatic confocal probe is stable and enables measurement repeatability at the nanometer level. With the proposed system, the major error sources, such as the relative axial and radial motions of the probe with respect to the sample, the material, colour and roughness of the measured sample, the relative deviation/tilt of the probe and the scanning speed are identified. Experimental test results show that the chromatic confocal probes are sensitive to these errors and that their measurement behaviour is highly dependent on them. (paper)

Development and Characterization of a Metal Injection Molding Bio Sourced Inconel 718 Feedstock Based on Polyhydroxyalkanoates

Directory of Open Access Journals (Sweden)

Alexandre Royer

2016-04-01

Full Text Available The binder plays the most important role in the metal injection molding (MIM process. It provides fluidity of the feedstock mixture and adhesion of the powder to keep the molded shape during injection molding. The binder must provide strength and cohesion for the molded part and must be easy to remove from the molded part. Moreover, it must be recyclable, environmentally friendly and economical. Also, the miscibility between polymers affects the homogeneity of the injected parts. The goal of this study is to develop a feedstock of superalloy Inconel 718 that is environmentally friendly. For these different binders, formulations based on polyethylene glycol (PEG, because of his water solubility property, and bio sourced polymers were studied. Polyhydroxyalkanoates (PHA were investigated as a bio sourced polymer due to its miscibility with the PEG. The result is compared to a standard formulation using polypropylene (PP. The chemical and rheological behavior of the binder formulation during mixing, injection and debinding process were investigated. The feedstock was characterized in the same way as the binders and the interactions between the powder and the binders were also studied. The results show the well adapted formulation of polymer binder to produce a superalloy Inconel 718 feedstock.

Design parameters and source terms: Volume 2, Source terms: Revision 0

International Nuclear Information System (INIS)

1987-09-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan---Conceptual Design Report SCP-CDR. The previous study identifies the data needs for the Environmental Assessment effort for seven possible salt repository sites. Volume 2 contains tables of source terms

Characterization of the thermolysis products of Nafion membrane: A potential source of perfluorinated compounds in the environment

Science.gov (United States)

Feng, Mingbao; Qu, Ruijuan; Wei, Zhongbo; Wang, Liansheng; Sun, Ping; Wang, Zunyao

2015-05-01

The thermal decomposition of Nafion N117 membrane, a typical perfluorosulfonic acid membrane that is widely used in various chemical technologies, was investigated in this study. Structural identification of thermolysis products in water and methanol was performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC/ESI-MS/MS). The fluoride release was studied using an ion-chromatography system, and the membrane thermal stability was characterized by thermogravimetric analysis. Notably, several types of perfluorinated compounds (PFCs) including perfluorocarboxylic acids were detected and identified. Based on these data, a thermolysis mechanism was proposed involving cleavage of both the polymer backbone and its side chains by attack of radical species. This is the first systematic report on the thermolysis products of Nafion by simulating its high-temperature operation and disposal process via incineration. The results of this study indicate that Nafion is a potential environmental source of PFCs, which have attracted growing interest and concern in recent years. Additionally, this study provides an analytical justification of the LC/ESI-MS/MS method for characterizing the degradation products of polymer electrolyte membranes. These identifications can substantially facilitate an understanding of their decomposition mechanisms and offer insight into the proper utilization and effective management on these membranes.

Design parameters and source terms: Volume 3, Source terms

International Nuclear Information System (INIS)

1987-10-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository in Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites. 11 refs., 9 tabs

Electron cyclotron resonance ion source plasma characterization by X-ray spectroscopy and X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Mascali, David, E-mail: davidmascali@lns.infn.it; Castro, Giuseppe; Celona, Luigi; Neri, Lorenzo; Gammino, Santo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Biri, Sándor; Rácz, Richárd; Pálinkás, József [Institute for Nuclear Research (Atomki), Hungarian Academy of Sciences, Bem tér 18/c, H-4026 Debrecen (Hungary); Caliri, Claudia [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università degli Studi di Catania, Dip.to di Fisica e Astronomia, via Santa Sofia 64, 95123 Catania (Italy); Romano, Francesco Paolo [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); CNR, Istituto per i Beni Archeologici e Monumentali, Via Biblioteca 4, 95124 Catania (Italy); Torrisi, Giuseppe [INFN–Laboratori Nazionali del Sud, Via S. Sofia 62, 95125 Catania (Italy); Università Mediterranea di Reggio Calabria, DIIES, Via Graziella, I-89100 Reggio Calabria (Italy)

2016-02-15

An experimental campaign aiming to investigate electron cyclotron resonance (ECR) plasma X-ray emission has been recently carried out at the ECRISs—Electron Cyclotron Resonance Ion Sources laboratory of Atomki based on a collaboration between the Debrecen and Catania ECR teams. In a first series, the X-ray spectroscopy was performed through silicon drift detectors and high purity germanium detectors, characterizing the volumetric plasma emission. The on-purpose developed collimation system was suitable for direct plasma density evaluation, performed “on-line” during beam extraction and charge state distribution characterization. A campaign for correlating the plasma density and temperature with the output charge states and the beam intensity for different pumping wave frequencies, different magnetic field profiles, and single-gas/gas-mixing configurations was carried out. The results reveal a surprisingly very good agreement between warm-electron density fluctuations, output beam currents, and the calculated electromagnetic modal density of the plasma chamber. A charge-coupled device camera coupled to a small pin-hole allowing X-ray imaging was installed and numerous X-ray photos were taken in order to study the peculiarities of the ECRIS plasma structure.

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.

FEASIBILITY STUDY II OF A MUON BASED NEUTRINO SOURCE.

Energy Technology Data Exchange (ETDEWEB)

GALLARDO,J.C.; OZAKI,S.; PALMER,R.B.; ZISMAN,M.

2001-06-30

The concept of using a muon storage ring to provide a well characterized beam of muon and electron neutrinos (a Neutrino Factory) has been under study for a number of years now at various laboratories throughout the world. The physics program of a Neutrino Factoryis focused on the relatively unexplored neutrino sector. In conjunction with a detector located a suitable distance from the neutrino source, the facility would make valuable contributions to the study of neutrino masses and lepton mixing. A Neutrino Factory is expected to improve the measurement accuracy of sin{sup 2}(2{theta}{sub 23}) and {Delta}m{sup 2}{sub 32} and provide measurements of sin{sup 2}(2{theta}{sub 13}) and the sign of {Delta}m{sup 2}{sub 32}. It may also be able to measure CP violation in the lepton sector.

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

Characterization of PM10 sources in the central Mediterranean

Science.gov (United States)

Calzolai, G.; Nava, S.; Lucarelli, F.; Chiari, M.; Giannoni, M.; Becagli, S.; Traversi, R.; Marconi, M.; Frosini, D.; Severi, M.; Udisti, R.; di Sarra, A.; Pace, G.; Meloni, D.; Bommarito, C.; Monteleone, F.; Anello, F.; Sferlazzo, D. M.

2015-12-01

The Mediterranean Basin atmosphere is influenced by both strong natural and anthropogenic aerosol emissions and is also subject to important climatic forcings. Several programs have addressed the study of the Mediterranean basin; nevertheless important pieces of information are still missing. In this framework, PM10 samples were collected on a daily basis on the island of Lampedusa (35.5° N, 12.6° E; 45 m a.s.l.), which is far from continental pollution sources (the nearest coast, in Tunisia, is more than 100 km away). After mass gravimetric measurements, different portions of the samples were analyzed to determine the ionic content by ion chromatography (IC), the soluble metals by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the total (soluble + insoluble) elemental composition by particle-induced x-ray emission (PIXE). Data from 2007 and 2008 are used in this study. The Positive Matrix Factorization (PMF) model was applied to the 2-year long data set of PM10 mass concentration and chemical composition to assess the aerosol sources affecting the central Mediterranean basin. Seven sources were resolved: sea salt, mineral dust, biogenic emissions, primary particulate ship emissions, secondary sulfate, secondary nitrate, and combustion emissions. Source contributions to the total PM10 mass were estimated to be about 40 % for sea salt, around 25 % for mineral dust, 10 % each for secondary nitrate and secondary sulfate, and 5 % each for primary particulate ship emissions, biogenic emissions, and combustion emissions. Large variations in absolute and relative contributions are found and appear to depend on the season and on transport episodes. In addition, the secondary sulfate due to ship emissions was estimated and found to contribute by about one-third to the total sulfate mass. Results for the sea-salt and mineral dust sources were compared with estimates of the same contributions obtained from independent approaches, leading to an

A Catalog of Moment Tensors and Source-type Characterization for Small Events at Uturuncu Volcano, Bolivia

Science.gov (United States)

Alvizuri, C. R.; Tape, C.

2015-12-01

We present a catalog of full seismic moment tensors for 63 events from Uturuncu volcano in Bolivia. The events were recorded during 2011-2012 in the PLUTONS seismic array of 24 broadband stations. Most events had magnitudes between 0.5 and 2.0 and did not generate discernible surface waves; the largest event was Mw 2.8. For each event we computed the misfit between observed and synthetic waveforms, and we also used first-motion polarity measurements to reduce the number of possible solutions. Each moment tensor solution was obtained using a grid search over the six-dimensional space of moment tensors. For each event we characterize the variation of moment tensor source type by plotting the misfit function in eigenvalue space, represented by a lune. We plot the optimal solutions for the 63 events on the lune in order to identify three subsets of the catalog: (1) a set of isotropic events, (2) a set of tensional crack events, and (3) a swarm of events southeast of the volcanic center that appear to be double couples. The occurrence of positively isotropic events is consistent with other published results from volcanic and geothermal regions. Several of these previous results, as well as our results, cannot be interpreted within the context of either an oblique opening crack or a crack-plus-double-couple model; instead they require a multiple-process source model. Our study emphasizes the importance of characterizing uncertainties for full moment tensors, and it provides strong support for isotropic events at Uturuncu volcano.

Characterization of source rocks and groundwater radioactivity at the Chihuahua valley

Energy Technology Data Exchange (ETDEWEB)

Renteria V, M.; Montero C, M.E.; Reyes C, M.; Herrera P, E.F.; Valenzuela H, M. [Centro de lnvestigacion en Materiales Avanzados, Miguel de Cervantes 120, 31109 Chihuahua, (Mexico); Rodriguez P, A. [World Wildlife Fund (WWF), Chihuahuan Desert Program, Coronado 1005, 31000 Chihuahua (Mexico); Manjon C, G.; Garcia T, R. [Universidad de Sevilla, Departamento de Fisica Aplicada 11, ETS Arquitectura, Av. Reina Mercedes 2, 41012 Sevilla, (Spain); Crespo, T. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), Av. Complutense 22, 28040 Madrid, (Spain)]. e-mail: elena.montero@cimav.edu.mx

2007-07-01

As part of a scientific research project about alpha radioactivity in groundwater for human consumption at the Chihuahua City, the characterization of rock sources of radioactivity around de Chihuahua valley was developed. The radioactivity of groundwater and sediments was determined, too. The radioactivity of uranium- and thorium- series isotopes contained in rocks was obtained by high resolution gamma-ray spectroscopy. Some representative values are 50 Bq/kg for the mean value of Bi-214 activity, and 121.5 Bq/kg for the highest value at West of the city. The activity of sediments, extracted during wells perforation, was determined using a Nal(TI) detector. A non-reported before uranium ore was localized at the San Marcos range formation. Its outcrops are inside the Chihuahua-Sacramento valley basin and its activity characterization was performed. Unusually high specific uranium activities, determined by alpha spectrometry, were obtained in water, plants, sediments and fish extracted at locations close to outcrops of uranium minerals. The activity of water of the San Marcos dam reached 7.7 Bq/L. The activity of fish, trapped at San Marcos dam, is 0.99 Bq/kg. Conclusions about the contamination of groundwater at North of Chihuahua City were obtained. (Author)

Characterization of source rocks and groundwater radioactivity at the Chihuahua valley

International Nuclear Information System (INIS)

Renteria V, M.; Montero C, M.E.; Reyes C, M.; Herrera P, E.F.; Valenzuela H, M.; Rodriguez P, A.; Manjon C, G.; Garcia T, R.; Crespo, T.

2007-01-01

As part of a scientific research project about alpha radioactivity in groundwater for human consumption at the Chihuahua City, the characterization of rock sources of radioactivity around de Chihuahua valley was developed. The radioactivity of groundwater and sediments was determined, too. The radioactivity of uranium- and thorium- series isotopes contained in rocks was obtained by high resolution gamma-ray spectroscopy. Some representative values are 50 Bq/kg for the mean value of Bi-214 activity, and 121.5 Bq/kg for the highest value at West of the city. The activity of sediments, extracted during wells perforation, was determined using a Nal(TI) detector. A non-reported before uranium ore was localized at the San Marcos range formation. Its outcrops are inside the Chihuahua-Sacramento valley basin and its activity characterization was performed. Unusually high specific uranium activities, determined by alpha spectrometry, were obtained in water, plants, sediments and fish extracted at locations close to outcrops of uranium minerals. The activity of water of the San Marcos dam reached 7.7 Bq/L. The activity of fish, trapped at San Marcos dam, is 0.99 Bq/kg. Conclusions about the contamination of groundwater at North of Chihuahua City were obtained. (Author)

Fugitive emission source characterization using a gradient-based optimization scheme and scalar transport adjoint

Science.gov (United States)

Brereton, Carol A.; Joynes, Ian M.; Campbell, Lucy J.; Johnson, Matthew R.

2018-05-01

Fugitive emissions are important sources of greenhouse gases and lost product in the energy sector that can be difficult to detect, but are often easily mitigated once they are known, located, and quantified. In this paper, a scalar transport adjoint-based optimization method is presented to locate and quantify unknown emission sources from downstream measurements. This emission characterization approach correctly predicted locations to within 5 m and magnitudes to within 13% of experimental release data from Project Prairie Grass. The method was further demonstrated on simulated simultaneous releases in a complex 3-D geometry based on an Alberta gas plant. Reconstructions were performed using both the complex 3-D transient wind field used to generate the simulated release data and using a sequential series of steady-state RANS wind simulations (SSWS) representing 30 s intervals of physical time. Both the detailed transient and the simplified wind field series could be used to correctly locate major sources and predict their emission rates within 10%, while predicting total emission rates from all sources within 24%. This SSWS case would be much easier to implement in a real-world application, and gives rise to the possibility of developing pre-computed databases of both wind and scalar transport adjoints to reduce computational time.

Synthesis and characterization of zeolite NaP using kaolin waste as a source of silicon and aluminum

Energy Technology Data Exchange (ETDEWEB)

Hildebrando, Edemarino Araujo, E-mail: edemarino@ufpa.br [Universidae Federal do Para (UFPA), Maraba, PA (Brazil). Fac. de Engenharia de Materias. Lab. de Materiais Ceramicos; Andrade, Christiano Gianesi Bastos; Valenzuela-Diaz, Francisco Rolando [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Dept. de Metalurgia e Engenharia de Materiais; Rocha Junior, Carlos Augusto Ferreira da; Neves, Roberto de Freitas [Universidae Federal do Para (UFPA), Maraba, PA (Brazil). Int. de Tecnologia. Fac. de Engenharia Quimica; Angelica, Romulo Simoes [Universidae Federal do Para (UFPA), Maraba, PA (Brazil). Inst. de Geociencias. Fac. de Geologia

2014-08-15

The synthesis of zeolite NaP using kaolin waste, from the Amazon region, as a predominant source of silicon and aluminum has been studied. The zeolitisation process occurred in hydrothermal conditions using static autoclaving and the effects of time, temperature, and the Si/Al ratio were investigated. The starting material and the phases formed as reaction products were characterized by XRD, SEM and FTIR. The results showed that pure zeolite NaP is hydrothermally synthesized, at 100 °C for 20 hours, using meta kaolin waste material in alkaline medium in presence of additional silica. The XRD and SEM analyses indicate that the synthesized zeolite presents good crystallinity. (author)

Synthesis and characterization of zeolite NaP using kaolin waste as a source of silicon and aluminum

International Nuclear Information System (INIS)

Hildebrando, Edemarino Araujo; Andrade, Christiano Gianesi Bastos; Valenzuela-Diaz, Francisco Rolando; Rocha Junior, Carlos Augusto Ferreira da; Neves, Roberto de Freitas; Angelica, Romulo Simoes

2014-01-01

The synthesis of zeolite NaP using kaolin waste, from the Amazon region, as a predominant source of silicon and aluminum has been studied. The zeolitisation process occurred in hydrothermal conditions using static autoclaving and the effects of time, temperature, and the Si/Al ratio were investigated. The starting material and the phases formed as reaction products were characterized by XRD, SEM and FTIR. The results showed that pure zeolite NaP is hydrothermally synthesized, at 100 °C for 20 hours, using meta kaolin waste material in alkaline medium in presence of additional silica. The XRD and SEM analyses indicate that the synthesized zeolite presents good crystallinity. (author)

Waste Characterization Methods

Energy Technology Data Exchange (ETDEWEB)

Vigil-Holterman, Luciana R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Naranjo, Felicia Danielle [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-02-02

This report discusses ways to classify waste as outlined by LANL. Waste Generators must make a waste determination and characterize regulated waste by appropriate analytical testing or use of acceptable knowledge (AK). Use of AK for characterization requires several source documents. Waste characterization documentation must be accurate, sufficient, and current (i.e., updated); relevant and traceable to the waste stream’s generation, characterization, and management; and not merely a list of information sources.

Waste Characterization Methods

International Nuclear Information System (INIS)

Vigil-Holterman, Luciana R.; Naranjo, Felicia Danielle

2016-01-01

This report discusses ways to classify waste as outlined by LANL. Waste Generators must make a waste determination and characterize regulated waste by appropriate analytical testing or use of acceptable knowledge (AK). Use of AK for characterization requires several source documents. Waste characterization documentation must be accurate, sufficient, and current (i.e., updated); relevant and traceable to the waste stream's generation, characterization, and management; and not merely a list of information sources.

Thermal-hydraulic studies of the Advanced Neutron Source cold source

International Nuclear Information System (INIS)

Williams, P.T.; Lucas, A.T.

1995-08-01

The Advanced Neutron Source (ANS), in its conceptual design phase at Oak Ridge National Laboratory, was to be a user-oriented neutron research facility producing the most intense steady-state flux of thermal and cold neutrons in the world. Among its many scientific applications, the production of cold neutrons was a significant research mission for the ANS. The cold neutrons come from two independent cold sources positioned near the reactor core. Contained by an aluminum alloy vessel, each cold source is a 410-mm-diam sphere of liquid deuterium that functions both as a neutron moderator and a cryogenic coolant. With nuclear heating of the containment vessel and internal baffling, steady-state operation requires close control of the liquid deuterium flow near the vessel's inner surface. Preliminary thermal-hydraulic analyses supporting the cold source design were performed with heat conduction simulations of the vessel walls and multidimensional computational fluid dynamics simulations of the liquid deuterium flow and heat transfer. This report presents the starting phase of a challenging program and describes the cold source conceptual design, the thermal-hydraulic feasibility studies of the containment vessel, and the future computational and experimental studies that were planned to verify the final design

Analysis of the Degradation of MOSFETs in Switching Mode Power Supply by Characterizing Source Oscillator Signals

Directory of Open Access Journals (Sweden)

Xueyan Zheng

2013-01-01

Full Text Available Switching Mode Power Supply (SMPS has been widely applied in aeronautics, nuclear power, high-speed railways, and other areas related to national strategy and security. The degradation of MOSFET occupies a dominant position in the key factors affecting the reliability of SMPS. MOSFETs are used as low-voltage switches to regulate the DC voltage in SMPS. The studies have shown that die-attach degradation leads to an increase in on-state resistance due to its dependence on junction temperature. On-state resistance is the key indicator of the health of MOSFETs. In this paper, an online real-time method is presented for predicting the degradation of MOSFETs. First, the relationship between an oscillator signal of source and on-state resistance is introduced. Because oscillator signals change when they age, a feature is proposed to capture these changes and use them as indicators of the state of health of MOSFETs. A platform for testing characterizations is then established to monitor oscillator signals of source. Changes in oscillator signal measurement were observed with aged on-state resistance as a result of die-attach degradation. The experimental results demonstrate that the method is efficient. This study will enable a method to predict the failure of MOSFETs to be developed.

Design parameters and source terms: Volume 2, Source terms: Revision 0

International Nuclear Information System (INIS)

1987-10-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report by Stearns Catalytic Corporation (SCC), entitled ''Design Parameters and Source Terms for a Two-Phase Repository Salt,'' 1985, to the level of the Site Characterization Plan - Conceptual Design Report. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible Salt Repository sites. 2 tabs

Study of the dosimetric response of Gallium Nitride (GaN): modeling, simulation and characterization on radiotherapy

International Nuclear Information System (INIS)

Wang, Ruoxi

2015-01-01

The work in this thesis has the objective to increase the measurement precision of the dosimetry based on the Gallium Nitride (GaN) transducer and develop its applications on radiotherapy. The study includes the aspects of modeling, simulation and characterization of this response in external radiotherapy and brachytherapy. In modeling, we have proposed two approaches to model the GaN transducer's response in external radiotherapy. For the first approach, a model has been built based on experimental data, while separating the primary and scattering component of the beam. For the second approach, we have adopted a response model initially developed for the silicon diodes for the GaN radioluminescent transducer. We have also proposed an original concept of bi-media dosimetry which evaluates the dose in tissue according to different responses from two media without prior information on the conditions of irradiation. This concept has been shown by Monte Carlo simulation. Moreover, for High Dose Rate brachytherapy, the response of GaN transducer irradiated by iridium 192 and cobalt 60 sources has been evaluated by Monte Carlo simulation and confirmed by the measurements. Studies on the property characterization of GaN radioluminescent transducer has been carried out with these sources as well. An instrumented phantom prototype with GaN probe has been developed for the HDR brachytherapy quality control. It allows a real-time verification of the physics parameters of a treatment (source dwell position, source dwell time, source activity). (author) [fr

Prevalence and methodologies for detection, characterization and subtyping of Listeria monocytogenes and L. ivanovii in foods and environmental sources

Directory of Open Access Journals (Sweden)

Jin-Qiang Chen

2017-09-01

Full Text Available Listeria monocytogenes, one of the most important foodborne pathogens, can cause listeriosis, a lethal disease for humans. L. ivanovii, which is closely related to L. monocytogenes, is also widely distributed in nature and infects mainly warm-blooded ruminants, causing economic loss. Thus, there are high priority needs for methodologies for rapid, specific, cost-effective and accurate detection, characterization and subtyping of L. monocytogenes and L. ivanovii in foods and environmental sources. In this review, we (A described L. monocytogenes and L. ivanovii, world-wide incidence of listeriosis, and prevalence of various L. monocytogenes strains in food and environmental sources; (B comprehensively reviewed different types of traditional and newly developed methodologies, including culture-based, antigen/antibody-based, LOOP-mediated isothermal amplification, matrix-assisted laser desorption ionization-time of flight-mass spectrometry, DNA microarray, and genomic sequencing for detection and characterization of L. monocytogenes in foods and environmental sources; (C comprehensively summarized different subtyping methodologies, including pulsed-field gel electrophoresis, multi-locus sequence typing, ribotyping, and phage-typing, and whole genomic sequencing etc. for subtyping of L. monocytogenes strains from food and environmental sources; and (D described the applications of these methodologies in detection and subtyping of L. monocytogenes in foods and food processing facilities.

A case study characterizing animal fecal sources in surface water using a mitochondrial DNA marker.

Science.gov (United States)

Bucci, John P; Shattuck, Michelle D; Aytur, Semra A; Carey, Richard; McDowell, William H

2017-08-01

Water quality impairment by fecal waste in coastal watersheds is a public health issue. The present study provided evidence for the use of a mitochondrial (mtDNA) marker to detect animal fecal sources in surface water. The accurate identification of fecal pollution is based on the notion that fecal microorganisms preferentially inhabit a host animal's gut environment. In contrast, mtDNA host-specific markers are inherent to eukaryotic host cells, which offers the advantage by detecting DNA from the host rather than its fecal bacteria. The present study focused on sampling water presumably from non-point sources (NPS), which can increase bacterial and nitrogen concentrations to receiving water bodies. Stream sampling sites located within the Piscataqua River Watershed (PRW), New Hampshire, USA, were sampled from a range of sites that experienced nitrogen inputs such as sewer and septic systems and suburban runoff. Three mitochondrial (mtDNA) gene marker assays (human, bovine, and canine) were tested from surface water. Nineteen sites were sampled during an 18-month period. Analyses of the combined single and multiplex assay results showed that the proportion of occurrence was highest for bovine (15.6%; n = 77) compared to canine (5.6%; n = 70) and human (5.7%; n = 107) mtDNA gene markers. For the human mtDNA marker, there was a statistically significant relationship between presence vs. absence and land use (Fisher's test p = 0.0031). This result was evident particularly for rural suburban septic, which showed the highest proportion of presence (19.2%) compared to the urban sewered (3.3%), suburban sewered (0%), and agricultural (0%) as well as forested septic (0%) sites. Although further testing across varied land use is needed, our study provides evidence for using the mtDNA marker in large watersheds.

Barrow Black Carbon Source and Impact Study Final Campaign Report

Energy Technology Data Exchange (ETDEWEB)

Barrett, Tate [Baylor Univ., Waco, TX (United States)

2014-07-01

The goal of the Barrow Black Carbon Source and Impact (BBCSI) Study was to characterize the concentration and isotopic composition of carbonaceous atmospheric particulate matter (PM) at the Atmospheric Radiation Measurement site in Barrow, AK. The carbonaceous component was characterized via measurement of the organic and black carbon (OC and BC) components of the total PM. To facilitate complete characterization of the particulate matter, filter-based collections were used, including a medium volume PM2.5 sampler and a high volume PM10 sampler. Thirty-eight fine (PM2.5) and 49 coarse (PM10) particulate matter fractions were collected at weekly and bi-monthly intervals. The PM2.5 sampler operated with minimal maintenance during the 12 month campaign. The PM10 sampler used for the BBCSI used standard Tisch hi-vol motors which have a known lifetime of ~1 month under constant use; this necessitated monthly maintenance and it is suggested that the motors be upgraded to industrial blowers for future deployment in the Arctic. The BBCSI sampling campaign successfully collected and archived 87 ambient atmospheric particulate matter samples from Barrow, AK from July 2012 to June 2013. Preliminary analysis of the organic and black carbon concentrations has been completed. This campaign confirmed known trends of high BC lasting from the winter through to spring haze periods and low BC concentrations in the summer.

Characterization of emissions from South Asian biofuels and application to source apportionment of carbonaceous aerosol in the Himalayas

Science.gov (United States)

Stone, Elizabeth A.; Schauer, James J.; Pradhan, Bidya Banmali; Dangol, Pradeep Man; Habib, Gazala; Venkataraman, Chandra; Ramanathan, V.

2010-03-01

This study focuses on improving source apportionment of carbonaceous aerosol in South Asia and consists of three parts: (1) development of novel molecular marker-based profiles for real-world biofuel combustion, (2) application of these profiles to a year-long data set, and (3) evaluation of profiles by an in-depth sensitivity analysis. Emissions profiles for biomass fuels were developed through source testing of a residential stove commonly used in South Asia. Wood fuels were combusted at high and low rates, which corresponded to source profiles high in organic carbon (OC) or high in elemental carbon (EC), respectively. Crop wastes common to the region, including rice straw, mustard stalk, jute stalk, soybean stalk, and animal residue burnings, were also characterized. Biofuel profiles were used in a source apportionment study of OC and EC in Godavari, Nepal. This site is located in the foothills of the Himalayas and was selected for its well-mixed and regionally impacted air masses. At Godavari, daily samples of fine particulate matter (PM2.5) were collected throughout the year of 2006, and the annual trends in particulate mass, OC, and EC followed the occurrence of a regional haze in South Asia. Maximum concentrations occurred during the dry winter season and minimum concentrations occurred during the summer monsoon season. Specific organic compounds unique to aerosol sources, molecular markers, were measured in monthly composite samples. These markers implicated motor vehicles, coal combustion, biomass burning, cow dung burning, vegetative detritus, and secondary organic aerosol as sources of carbonaceous aerosol. A molecular marker-based chemical mass balance (CMB) model provided a quantitative assessment of primary source contributions to carbonaceous aerosol. The new profiles were compared to widely used biomass burning profiles from the literature in a sensitivity analysis. This analysis indicated a high degree of stability in estimates of source

Radiation studies in the antiproton source

International Nuclear Information System (INIS)

Church, M.

1990-01-01

Experiment E760 has a lead glass (Pb-G) calorimeter situated in the antiproton source tunnel in the accumulator ring at location A50. This location is exposed to radiation from several sources during antiproton stacking operations. A series of radiation studies has been performed over the last two years to determine the sources of this radiation and as a result, some shielding has been installed in the antiproton source in order to protect the lead glass from radiation damage

Sourcing Team Behavior in Project-Based MNE's

DEFF Research Database (Denmark)

Hansen, Anders Peder Lysholm

2014-01-01

across the three cases was characterized by conflict between departments represented in the category teams. This resulted in unfortunate sourcing team behaviour and unaligned performance management, which in turn had a number of adverse effects. Further research on how to create a holistic and balanced......This paper presents and discusses a multiple case study of three cross-functional category teams responsible for sourcing critical components within multi-national, project-based enterprises. The study focused on behaviour and management of the sourcing teams and found that the sourcing process...... team perspective in the sourcing teams is suggested....

Dosimetric study for characterization of a postal system of quality control in brachytherapy

International Nuclear Information System (INIS)

Alves, Victor Gabriel Leandro; Queiroz Filho, Pedro Pacheco de; Santos, Denison de Souza; Begalli, Marcia

2009-01-01

This work presents a dosimetric study of a postal system, to be developed for measurements of brachytherapy. It was projected a PMMA phantom with orifices for insertion of the high dose 192 Ir source and the T L dosemeters. The system was characterized with using of Monte Carlo simulations, using the dosimetric magnitudes defined at the T G-43 of AAPM, as function of radial dose g(f)

Characterization of a pulsed x-ray source for fluorescent lifetime measurements

International Nuclear Information System (INIS)

Blankespoor, S.C.; Derenzo, S.E.; Moses, W.W.; Rossington, C.S.; Ito, M.; Oba, K.

1994-01-01

To search for new, fast, inorganic scintillators, the authors have developed a bench-top pulsed x-ray source for determining fluorescent lifetimes and wavelengths of compounds in crystal or powdered form. This source uses a light-excited x-ray tube which produces x-rays when light from a laser diode strikes its photocathode. The x-ray tube has a tungsten anode, a beryllium exit window, a 30 kV maximum tube bias, and a 50 μA maximum average cathode current. The laser produces 3 x 10 7 photons at 650 nm per ∼100 ps pulse, with up to 10 7 pulses/sec. The time spread for the laser diode, x-ray tube, and a microchannel plate photomultiplier tube is less than 120 ps fwhm. The mean x-ray energy at tube biases of 20, 25, and 30 kV is 9.4, 10.3, and 11.1 keV, respectively. The authors measured 140, 230, and 330 x-ray photons per laser diode pulse per steradian, at tube biases of 20, 25, and 30 kV, respectively. Background x-rays due to dark current occur at a rate of 1 x 10 6 and 3 x 10 6 photons/sec/steradian at biases of 25 and 30 kV, respectively. Data characterizing the x-ray output with an aluminum filter in the x-ray beam are also presented

New method for selection and characterization of single-source events in Ni+Ni collisions at 32 A.MeV

International Nuclear Information System (INIS)

Maskay-Wallez, Anne-Marie

1999-01-01

The study of heavy ion collisions, with the help of such efficient multi-detectors as INDRA, has shown the persistence of reactions leading to single-source events, up to bombarding energies higher than the Fermi one. These events could help characterizing an expected phase transition in nuclear matter. Whatever interesting they may be, the single-source events correspond to a small part of the total cross section, which makes them difficult to isolate and therefore to analyze. That is why different selection means have been tested - thanks to the 'Simon' event generator - on a simulated Ni + Ni at 32 A·MeV sample, before any application to the INDRA experimental data. As the known methods based on global variables did not prove effective, a set of new 4-dimensional quantities has been built, whose main advantage lies in a better description of physical events. From a Discriminant Analysis performed on 625 of these new 'moments' proceeds a highly discriminant variable, called D 625 . The experimental cross section associated with D 625 -selected single-source events amounts to 170 mb at 32 A·MeV. Such quasi-fusion events are shown to disappear at about 60 A·MeV. As regards the deexcitation mode of the 32 A·MeV Ni + Ni single-source events, an extensive experimental study and comparisons of the data with two reference models seem to confirm the hypothesis of a transition between fusion-evaporation and simultaneous multifragmentation mechanisms. (author)

A characterization and optimization study of Gamble II as an X-ray bremsstrahlung source

International Nuclear Information System (INIS)

Oliphant, W.F.; Boller, J.R.; Brown, D.G.; Cooperstein, G.; Dozier, C.M.; Stephanakis, S.J.

1982-01-01

The adverse effects of radiation on solid state devices are strongly spectrum dependent. It is thus essential that the radiation spectrum from flash x-ray sources be available when they are used as facilities for testing electronic components. This paper describes a preliminary study in which previously developed computer codes were used to calculate the radiation spectrum produced by NRL's Gamble II pulsed power generator. To determine how well the calculated spectrum matched the experimental one, doses in CaF 2 -Mn TLD's were computed for the dosimeters placed behind various thicknesses of Cu and Pb filters and compared with the experimentally measured doses. Using a diode model that was consistent with presently understood electron beam behavior, a spectrum was generated which predicted TLD doses to within about 15% of the experimentally measured values

Isolation and characterization of yeasts capable of efficient utilization of hemicellulosic hydrolyzate as the carbon source.

Science.gov (United States)

Cassa-Barbosa, L A; Procópio, R E L; Matos, I T S R; Filho, S A

2015-09-28

Few yeasts have shown the potential to efficiently utilize hemicellulosic hydrolyzate as the carbon source. In this study, microorganisms isolated from the Manaus region in Amazonas, Brazil, were characterized based on their utilization of the pentoses, xylose, and arabinose. The yeasts that showed a potential to assimilate these sugars were selected for the better utilization of lignocellulosic biomass. Two hundred and thirty seven colonies of unicellular microorganisms grown on hemicellulosic hydrolyzate, xylose, arabinose, and yeast nitrogen base selective medium were analyzed. Of these, 231 colonies were subjected to sugar assimilation tests. One hundred and twenty five of these were shown to utilize hydrolyzed hemicellulose, xylose, or arabinose as the carbon source for growth. The colonies that showed the best growth (N = 57) were selected, and their internal transcribed spacer-5.8S rDNA was sequenced. The sequenced strains formed four distinct groups in the phylogenetic tree, and showed a high percentage of similarity with Meyerozyma caribbica, Meyerozyma guilliermondii, Trichosporon mycotoxinivorans, Trichosporon loubieri, Pichia kudriavzevii, Candida lignohabitans, and Candida ethanolica. The discovery of these xylose-fermenting yeasts could attract widespread interest, as these can be used in the cost-effective production of liquid fuel from lignocellulosic materials.

Experimental determination of dosimetric characterization of a newly designed encapsulated interstitial brachytherapy source of 103Pd-model Pd-1

International Nuclear Information System (INIS)

Nath, Ravinder; Yue Ning; Roa, Eduardo

2002-01-01

A newly designed encapsulated 103 Pd source has been introduced (BrachySeed trade mark sign -Pd-103, also named Model Pd-1, manufactured by DRAXIMAGE Inc. and distributed by Cytogen Corp.) for interstitial brachytherapy to provide more isotropic dose distributions. In this work, the dosimetric characteristics of the 103 Pd source were measured with micro LiF TLD chips and dosimetry parameters were characterized based upon the American Association of Physicists in Medicine (AAPM) Task Group No. 43 formalism. The dose rate constant of the sources was determined to be 0.66±0.05 cGy h-1 U-1. The radial dose function was measured and was found to be similar to that of the Theragenics Model 200 103 Pd source. The anisotropy constant for the Model Pd-1 source was determined to be 1.03

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.

Online characterization of planetary surfaces: PlanetServer, an open-source analysis and visualization tool

Science.gov (United States)

Marco Figuera, R.; Pham Huu, B.; Rossi, A. P.; Minin, M.; Flahaut, J.; Halder, A.

2018-01-01

The lack of open-source tools for hyperspectral data visualization and analysis creates a demand for new tools. In this paper we present the new PlanetServer, a set of tools comprising a web Geographic Information System (GIS) and a recently developed Python Application Programming Interface (API) capable of visualizing and analyzing a wide variety of hyperspectral data from different planetary bodies. Current WebGIS open-source tools are evaluated in order to give an overview and contextualize how PlanetServer can help in this matters. The web client is thoroughly described as well as the datasets available in PlanetServer. Also, the Python API is described and exposed the reason of its development. Two different examples of mineral characterization of different hydrosilicates such as chlorites, prehnites and kaolinites in the Nili Fossae area on Mars are presented. As the obtained results show positive outcome in hyperspectral analysis and visualization compared to previous literature, we suggest using the PlanetServer approach for such investigations.

Characterizing Sources of Small DC Motor Noise and Vibration

Directory of Open Access Journals (Sweden)

Yong Thung Cho

2018-02-01

Full Text Available Small direct current (DC motors are widely used due to their low cost and compact structure. Small DC motors of various designs are available on the market in different sizes. The smaller the motor, the more closely it may be used by individuals. Contrary to the size and simplicity of these motors in terms of structural design, sources of motor noise and vibration can be quite diverse and complicated. In this study, the source of motor noise and vibration was visualized over a very wide range of frequencies. The particle velocity of the motor was reconstructed from nearfield sound pressure measurements of motor noise. In addition to noncontact measurements conducted on a motor running at constant speed, the particle velocity of a stationary motor due to the impulse of an impact hammer was measured with an accelerometer. Furthermore, motor noise was measured under motor run-up conditions with different rotational speeds. As a result, by combination of these three methods, the sources of motor noise were accurately identified over a wide range of frequencies.

Antioxidants: Characterization, natural sources, extraction and analysis

OpenAIRE

OROIAN, MIRCEA; Escriche Roberto, Mª Isabel

2015-01-01

[EN] Recently many review papers regarding antioxidants fromdifferent sources and different extraction and quantification procedures have been published. However none of them has all the information regarding antioxidants (chemistry, sources, extraction and quantification). This article tries to take a different perspective on antioxidants for the new researcher involved in this field. Antioxidants from fruit, vegetables and beverages play an important role in human health, fo...

Measuring The Variability Of Gamma-Ray Sources With AGILE

International Nuclear Information System (INIS)

Chen, Andrew W.; Vercellone, Stefano; Pellizzoni, Alberto; Tavani, Marco

2005-01-01

Variability in the gamma-ray flux above 100 MeV at various time scales is one of the primary characteristics of the sources detected by EGRET, both allowing the identification of individual sources and constraining the unidentified source classes. We present a detailed simulation of the capacity of AGILE to characterize the variability of gamma-ray sources, discussing the implications for source population studies

Rapid Source Characterization of the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake

Science.gov (United States)

Hayes, Gavin P.

2011-01-01

On March 11th, 2011, a moment magnitude 9.0 earthquake struck off the coast of northeast Honshu, Japan, generating what may well turn out to be the most costly natural disaster ever. In the hours following the event, the U.S. Geological Survey National Earthquake Information Center led a rapid response to characterize the earthquake in terms of its location, size, faulting source, shaking and slip distributions, and population exposure, in order to place the disaster in a framework necessary for timely humanitarian response. As part of this effort, fast finite-fault inversions using globally distributed body- and surface-wave data were used to estimate the slip distribution of the earthquake rupture. Models generated within 7 hours of the earthquake origin time indicated that the event ruptured a fault up to 300 km long, roughly centered on the earthquake hypocenter, and involved peak slips of 20 m or more. Updates since this preliminary solution improve the details of this inversion solution and thus our understanding of the rupture process. However, significant observations such as the up-dip nature of rupture propagation and the along-strike length of faulting did not significantly change, demonstrating the usefulness of rapid source characterization for understanding the first order characteristics of major earthquakes.

Study of the 137Cs Stabilizer Source

Directory of Open Access Journals (Sweden)

GAO Yan;WANG Yan-ling;XU Zhi-jian;XU Liang;REN Chun-xia;TAN Xiao-ming;CUI Hong-qi

2014-02-01

Full Text Available The attenuation laws of the Cesium -137 γ-ray penetrating the ceramic core、stainless steel and tungsten steel were studied. The radioactivity of the 137Cs stabilizer source was determined through the surface dose rate of 137Cs stabilizer sources. In addition, the adsorption properties of the ceramic core were studied to improve the stability of the output rate, and established a production line. The application results showed that the output rate of ray source was accurate and was of a good consistency. At present, the source had been used in logging lithology, and achieved the realization of domestic product.

Characterization of domestic gray water from point source to determine the potential for urban residential reuse: a short review

Science.gov (United States)

Edwin, Golda A.; Gopalsamy, Poyyamoli; Muthu, Nandhivarman

2014-03-01

This study aims to discern the domestic gray water (GW) sources that is least polluting, at the urban households of India, by examining the GW characteristics, comparing with literature data, reuse standards and suitable treatment technologies. In view of this, the quantitative and qualitative characteristics of domestic GW originating from bath, wash basin, laundry and kitchen sources are determined and compared with established standards for reuse requirements. Quality of different gray water sources is characterized with respect to the physical, chemical, biological, nutrient, ground element and heavy metal properties. The pollutant loads indicate that the diversion techniques are not suitable for household application and, therefore, treatment is necessary prior to storage and reuse. It is observed that the total volume of GW generated exceeds the reuse requirement for suggested reuse such as for flushing and gardening/irrigation. In spite of generating less volume, the kitchen source is found to be the major contributor for most of the pollutant load and, therefore, not recommended to be considered for treatment. It is concluded that treatment of GW from bathroom source alone is sufficient to meet the onsite reuse requirements and thereby significantly reduce the potable water consumption by 28.5 %. Constructed wetland systems and constructed soil filters are suggested as suitable treatment alternatives owing to its ability to treat highly variable pollutant load with lower operational and maintenance cost, which is more practical for tropical and developing countries.

Detection and Characterization of Ground Displacement Sources from Variational Bayesian Independent Component Analysis of GPS Time Series

Science.gov (United States)

Gualandi, A.; Serpelloni, E.; Belardinelli, M. E.

2014-12-01

A critical point in the analysis of ground displacements time series is the development of data driven methods that allow to discern and characterize the different sources that generate the observed displacements. A widely used multivariate statistical technique is the Principal Component Analysis (PCA), which allows to reduce the dimensionality of the data space maintaining most of the variance of the dataset explained. It reproduces the original data using a limited number of Principal Components, but it also shows some deficiencies. Indeed, PCA does not perform well in finding the solution to the so-called Blind Source Separation (BSS) problem, i.e. in recovering and separating the original sources that generated the observed data. This is mainly due to the assumptions on which PCA relies: it looks for a new Euclidean space where the projected data are uncorrelated. Usually, the uncorrelation condition is not strong enough and it has been proven that the BSS problem can be tackled imposing on the components to be independent. The Independent Component Analysis (ICA) is, in fact, another popular technique adopted to approach this problem, and it can be used in all those fields where PCA is also applied. An ICA approach enables us to explain the time series imposing a fewer number of constraints on the model, and to reveal anomalies in the data such as transient signals. However, the independence condition is not easy to impose, and it is often necessary to introduce some approximations. To work around this problem, we use a variational bayesian ICA (vbICA) method, which models the probability density function (pdf) of each source signal using a mix of Gaussian distributions. This technique allows for more flexibility in the description of the pdf of the sources, giving a more reliable estimate of them. Here we present the application of the vbICA technique to GPS position time series. First, we use vbICA on synthetic data that simulate a seismic cycle

Surface characterization protocol for precision aspheric optics

Science.gov (United States)

Sarepaka, RamaGopal V.; Sakthibalan, Siva; Doodala, Somaiah; Panwar, Rakesh S.; Kotaria, Rajendra

2017-10-01

In Advanced Optical Instrumentation, Aspherics provide an effective performance alternative. The aspheric fabrication and surface metrology, followed by aspheric design are complementary iterative processes for Precision Aspheric development. As in fabrication, a holistic approach of aspheric surface characterization is adopted to evaluate actual surface error and to aim at the deliverance of aspheric optics with desired surface quality. Precision optical surfaces are characterized by profilometry or by interferometry. Aspheric profiles are characterized by contact profilometers, through linear surface scans to analyze their Form, Figure and Finish errors. One must ensure that, the surface characterization procedure does not add to the resident profile errors (generated during the aspheric surface fabrication). This presentation examines the errors introduced post-surface generation and during profilometry of aspheric profiles. This effort is to identify sources of errors and is to optimize the metrology process. The sources of error during profilometry may be due to: profilometer settings, work-piece placement on the profilometer stage, selection of zenith/nadir points of aspheric profiles, metrology protocols, clear aperture - diameter analysis, computational limitations of the profiler and the software issues etc. At OPTICA, a PGI 1200 FTS contact profilometer (Taylor-Hobson make) is used for this study. Precision Optics of various profiles are studied, with due attention to possible sources of errors during characterization, with multi-directional scan approach for uniformity and repeatability of error estimation. This study provides an insight of aspheric surface characterization and helps in optimal aspheric surface production methodology.

Emission and source characterization of monoaromatic hydrocarbons from coke production

Energy Technology Data Exchange (ETDEWEB)

He, Q.S.; Wang, X.M.; Sheng, G.Y.; Fu, J.M. [Chinese Academy of Sciences, Guangzhou (China). State Key Laboratory of Organic Geochemistry

2005-09-15

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.

[Emission and source characterization of monoaromatic hydrocarbons from coke production].

Science.gov (United States)

He, Qiu-Sheng; Wang, Xin-Ming; Sheng, Guo-Ying; Fu, Jia-Mo

2005-09-01

Monoaromatic hydrocarbons (MAHs) from indigenous and industrial coking processes are studied in Shanxi province. They are sampled on the top of coke ovens and in the chimneys using stainless steel canister and determined by GC/MSD after preconcentration with liquid nitrogen. Benzene, toluene and xylene are the main components among MAHs emitted from coking processes. Benzene and the total MAHs concentrations were as high as 3421.0 microg/m3 and 4 865.9 microg/m3 in the air from indigenous coking, 548.7 microg/m3 and 1 054.8 microg/m3 in the oventop air from industrial coking, and 1 376.4 microg/m3 and 1 819.4 microg/m3 in stack gas from industrial coking, respectively. The MAHs concentrations vary greatly during the indigenous coking process, which in the prophase (from firing to 10 days) is obviously higher than in the anaphase (10 days to quenching the coke). In industrial coking the MAHs in the oventop air are highest when charging the coal and next when transferring the hot coke, but in stack gas they are highest when charging coal and lowest when transferring the coke. Benzene, toluene, ethylbenzene and xylene (BTEX) in industrial coking samples show good linearity, indicating that MAHs in industrial coking might come predominantly from coal pyrolysis; but BTEX distribute dispersedly in indigenous coking samples, indicating that its emission might be affected by many factors. In all samples BTEX ratios especially high B/E ratio, is unique among MAHs sources, and might be helpful to characterize pollution from coking.

Statistical studies of powerful extragalactic radio sources

Energy Technology Data Exchange (ETDEWEB)

Macklin, J T

1981-01-01

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

Study of the Release Process of Open Source Software: Case Study

OpenAIRE

Eide, Tor Erik

2007-01-01

This report presents the results of a case study focusing on the release process of open source projects initiated with commercial motives. The purpose of the study is to gain an increased understanding of the release process, how a community can be attracted to the project, and how the interaction with the community evolves in commercial open source initiatives. Data has been gathered from four distinct sources to form the basis of this thesis. A thorough review of the open source literatu...

Characterization and packaging of disused sealed radioactive sources; Caracterizacion y acondicionamiento de fuentes radiactivas selladas en desuso

Energy Technology Data Exchange (ETDEWEB)

Aguilar, S.L. [Instituto Boliviano de Ciencia y Tecnologia Nuclear (IBTEN), La Paz (Bolivia, Plurinational State of)

2013-07-01

In Bolivia are generated disused sealed sources and radioactive waste resulting from the use of radioactive materials in industrial, research and medicine. The last includes the diagnosis and treatment. Whereas exposure to ionizing radiation is a potential hazard to personnel who applies it, to those who benefit from its use or for the community at large, it is necessary to control the activities in this field. The Instituto Boliviano de Ciencia y Tecnologia Nuclear - IBTEN is working on a regional project from International Atomic Energy Agency - IAEA, RLA/09/062 Project - TSA 4, Strengthening the National Infrastructure and Regulatory Framework for the Safe Management of Radioactive waste in Latin America. This Project has strengthened the regulatory framework regarding the safe management of radioactive waste. The aim of this work was focused primarily on the security aspects in the safe management of disused sealed sources. The tasks are listed below: 1. Characterization of disused sealed sources 2. Preparation for transport to temporary storage 3. Control of all disused radioactive sources. (author)

Characterization of Staphylococcus aureus isolates from raw milk sources in Victoria, Australia.

Science.gov (United States)

McMillan, Kate; Moore, Sean C; McAuley, Catherine M; Fegan, Narelle; Fox, Edward M

2016-07-29

Highly pathogenic strains of Staphylococcus aureus can cause disease in both humans and animals. In animal species, including ruminants, S. aureus may cause severe or sub-clinical mastitis. Dairy animals with mastitis frequently shed S. aureus into the milk supply which can lead to food poisoning in humans. The aim of this study was to use genotypic and immunological methods to characterize S. aureus isolates from milk-related samples collected from 7 dairy farms across Victoria. A total of 30 S. aureus isolates were collected from milk and milk filter samples from 3 bovine, 3 caprine and 1 ovine dairy farms across Victoria, Australia. Pulsed Field Gel Electrophoresis (PFGE) identified 11 distinct pulsotypes among isolates; all caprine and ovine isolates shared greater than 80 % similarity regardless of source. Conversely, bovine isolates showed higher diversity. Multi-Locus Sequence Typing (MLST) identified 5 different sequence types (STs) among bovine isolates, associated with human or ruminant lineages. All caprine and ovine isolates were ST133, or a single allele variant of ST133. Two new novel STs were identified among isolates in this study (ST3183 and ST3184). With the exception of these 2 new STs, eBURST analysis predicted all other STs to be founding members of their associated clonal complexes (CCs). Analysis of genetic markers revealed a diverse range of classical staphylococcal enterotoxins (SE) among isolates, with 11 different SEs identified among bovine isolates, compared with just 2 among caprine and ovine isolates. None of the isolates contained mecA, or were resistant to oxacillin. The only antibiotic resistance identified was that of a single isolate resistant to penicillin; this isolate also contained the penicillin resistance gene blaZ. Production of SE was observed at 16 °C and/or 37 °C in milk, however no SE production was detected at 12 °C. Although this study characterized a limited number of isolates, bovine-associated isolates

Characterizing and sourcing ambient PM2.5 over key emission regions in China I: Water-soluble ions and carbonaceous fractions

Science.gov (United States)

Zhou, Jiabin; Xing, Zhenyu; Deng, Junjun; Du, Ke

2016-06-01

During the past decade, huge research resources have been devoted into studies of air pollution in China, which generated abundant datasets on emissions and pollution characterization. Due to the complex nature of air pollution as well as the limitations of each individual investigating approach, the published results were sometimes perplexing and even contradicting. This research adopted a multi-method approach to investigate region-specific air pollution characteristics and sources in China, results obtained using different analytical and receptor modeling methods were inter-compared for validation and interpretation. A year-round campaign was completed for comprehensive characterization of PM2.5 over four key emission regions: Beijing-Tianjin-Hebei (BTH), Yangzi River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SB). Atmospheric PM2.5 samples were collected from 10/2012 to 08/2013 at four regional sites, located on the diffusion paths of air masses from their corresponding megacities (i.e., Beijing, Shanghai, Guangzhou, and Chengdu). The annual average PM2.5 mass concentrations showed distinct regional difference, with the highest observed at BTH and lowest at PRD site. Nine water-soluble ions together contributed 33-41% of PM2.5 mass, with three dominant ionic species being SO42-, NO3-, NH4+, and carbonaceous particulate matter contributed 16-23% of PM2.5 mass. This implied that combustion and secondary formation were the main sources for PM2.5 in China. In addition, SO42-, NO3-, NH4+, and carbonaceous components (OC, EC) showed clear seasonal patterns with the highest concentration occurring in winter while the lowest in summer. Principal component analysis performed on aerosol data revealed that vehicular emissions, coal/biomass combustion, industry source, soil dust as well as secondary formation were the main potential sources for the ionic components of PM2.5. The characteristic chemical species combined with back trajectory analysis indicated

An Open-Source Approach for Catchment's Physiographic Characterization

Science.gov (United States)

Di Leo, M.; Di Stefano, M.

2013-12-01

A water catchment's hydrologic response is intimately linked to its morphological shape, which is a signature on the landscape of the particular climate conditions that generated the hydrographic basin over time. Furthermore, geomorphologic structures influence hydrologic regimes and land cover (vegetation). For these reasons, a basin's characterization is a fundamental element in hydrological studies. Physiographic descriptors have been extracted manually for long time, but currently Geographic Information System (GIS) tools ease such task by offering a powerful instrument for hydrologists to save time and improve accuracy of result. Here we present a program combining the flexibility of the Python programming language with the reliability of GRASS GIS, which automatically performing the catchment's physiographic characterization. GRASS (Geographic Resource Analysis Support System) is a Free and Open Source GIS, that today can look back on 30 years of successful development in geospatial data management and analysis, image processing, graphics and maps production, spatial modeling and visualization. The recent development of new hydrologic tools, coupled with the tremendous boost in the existing flow routing algorithms, reduced the computational time and made GRASS a complete toolset for hydrological analysis even for large datasets. The tool presented here is a module called r.basin, based on GRASS' traditional nomenclature, where the "r" stands for "raster", and it is available for GRASS version 6.x and more recently for GRASS 7. As input it uses a Digital Elevation Model and the coordinates of the outlet, and, powered by the recently developed r.stream.* hydrological tools, it performs the flow calculation, delimits the basin's boundaries and extracts the drainage network, returning the flow direction and accumulation, the distance to outlet and the hill slopes length maps. Based on those maps, it calculates hydrologically meaningful shape factors and

Fluvial sediments characterization of Hornád river in its chosen parts (preliminary study

Directory of Open Access Journals (Sweden)

Stela Hanigovská

2008-12-01

Full Text Available Knowledge of main river sedimentary characteristics is very important source of information for next study or potentialcommercial usage of fluvial sediments. In paper is shown characterization of sediment distribution in chosen part of the river Hornád.Three main facial types were studied and described – gravel, sand and clay. Model created in this study shows that Hornád is a riverwith predominant gravel transport. This model also shows a sufficient amount of gravel for commercial use in some parts of the river.

252Cf-source-driven noise analysis measurements for characterization of concrete highly enriched uranium (HEU) storage vaults

International Nuclear Information System (INIS)

Valentine, T.E.; Mihalczo, J.T.

1993-01-01

The 252 Cf-source-driven noise analysis method has been used in measurements for subcritical configurations of fissile systems for a variety of applications. Measurements of 25 fissile systems have been performed with a wide variety of materials and configurations. This method has been applied to measurements for (1) initial fuel loading of reactors, (2) quality assurance of reactor fuel elements, (3) fuel preparation facilities, (4) fuel processing facilities, (5) fuel storage facilities, (6) zero-power testing of reactors, and (7) verification of calculational methods for assemblies with the neutron k 252 Cf source and commercially available detectors was feasible and to determine if the measurement could characterize the ability of the concrete to isolate the fissile material

Low-level rf control of Spallation Neutron Source: System and characterization

Directory of Open Access Journals (Sweden)

Hengjie Ma

2006-03-01

Full Text Available The low-level rf control system currently commissioned throughout the Spallation Neutron Source (SNS LINAC evolved from three design iterations over 1 yr intensive research and development. Its digital hardware implementation is efficient, and has succeeded in achieving a minimum latency of less than 150 ns which is the key for accomplishing an all-digital feedback control for the full bandwidth. The control bandwidth is analyzed in frequency domain and characterized by testing its transient response. The hardware implementation also includes the provision of a time-shared input channel for a superior phase differential measurement between the cavity field and the reference. A companion cosimulation system for the digital hardware was developed to ensure a reliable long-term supportability. A large effort has also been made in the operation software development for the practical issues such as the process automations, cavity filling, beam loading compensation, and the cavity mechanical resonance suppression.

CF3CH(ONO)CF3: Synthesis, IR spectrum, and use as OH radical source for kinetic and mechanistic studies

DEFF Research Database (Denmark)

Andersen, Mads Peter Sulbæk; Hurley, MD; Ball, JC

2003-01-01

The synthesis, IR spectrum, and first-principles characterization of CF3CH(ONO)CF3 as well as its use as an OH radical source in kinetic and mechanistic studies are reported. CF3CH(ONO)CF3 exists in two conformers corresponding to rotation about the RCO-NO bond. The more prevalent trans conformer......C(O)CF3 and, by implication, OH radicals in 100% yield. CF3CH(ONO)CF3 photolysis is a convenient source of OH radicals in the studies of the yields of CO, CO2, HCHO, and HC(O)OH products which can be difficult to measure using more conventional OH radical sources (e.g., CH3ONO photolysis). CF3CH...

Source characterization using compound composition and stable carbon isotope ratio of PAHs in sediments from lakes, harbor, and shipping waterway

International Nuclear Information System (INIS)

Kim, Moonkoo; Kennicutt, Mahlon C.; Qian, Yaorong

2008-01-01

Molecular compositions and compound specific stable carbon isotope ratios of polycyclic aromatic hydrocarbons (PAH) isolated from sediments were used to characterize possible sources of contamination at an urban lake, a harbor, a shipping waterway, and a relatively undisturbed remote lake in the northwest United States. Total PAH concentrations in urban lake sediments ranged from 66.0 to 16,500 μg g -1 dry wt. with an average of 2600 μg g -1 , which is ∼ 50, 100, and 400 times higher on average than PAH in harbor (48 μg g -1 on average), shipping waterway (26 μg g -1 ), and remote lake (7 μg g -1 ) sediments, respectively. The PAH distribution patterns, methyl phenanthrene/phenanthrene ratios, and a pyrogenic index at the sites suggest a pyrogenic origin for PAHs. Source characterization using principal component analysis and various molecular indices including C2-dibenzothiophenes/C2-phenanthrenes, C3-dibenzothiophenes/C3-phenanthrenes, and C2-chrysenes/C2-phenanthrenes ratios, was able to differentiate PAH deposited in sediments from the four sites. The uniqueness of the source of the sediment PAHs from urban lake was also illustrated by compound specific stable carbon isotope analysis. It was concluded that urban lake sediments are accumulating PAH from sources that are unique from contamination detected at nearby sites in the same watershed

From laser-plasma accelerators to femtosecond X-ray sources: study, development and applications

International Nuclear Information System (INIS)

Corde, S.

2012-01-01

During the relativistic interaction between a short and intense laser pulse and an underdense plasma, electrons can be injected and accelerated up to hundreds of MeV in an accelerating structure formed in the wake of the pulse: this is the so-called laser-plasma accelerator. One of the major perspectives for laser-plasma accelerators resides in the realization of compact sources of femtosecond x-ray beams. In this thesis, two x-ray sources was studied and developed. The betatron radiation, intrinsic to laser-plasma accelerators, comes from the transverse oscillations of electrons during their acceleration. Its characterization by photon counting revealed an x-ray beam containing 10"9 photons, with energies extending above 10 keV. We also developed an all-optical Compton source producing photons with energies up to hundreds of keV, based on the collision between a photon beam and an electron beam. The potential of these x-ray sources was highlighted by the realization of single shot phase contrast imaging of a biological sample. Then, we showed that the betatron x-ray radiation can be a powerful tool to study the physics of laser-plasma acceleration. We demonstrated the possibility to map the x-ray emission region, which gives a unique insight into the interaction, permitting us for example to locate the region where electrons are injected. The x-ray angular and spectral properties allow us to gain information on the transverse dynamics of electrons during their acceleration. (author)

Identification and characterization of five non-traditional-source categories: Catastrophic/accidental releases, vehicle repair facilities, recycling, pesticide application, and agricultural operations. Final report, September 1991-September 1992

International Nuclear Information System (INIS)

Sleva, S.; Pendola, J.A.; McCutcheon, J.; Jones, K.; Kersteter, S.L.

1993-03-01

The work is part of EPA's program to identify and characterize emissions sources not currently accounted for by either the existing Aerometric Information Retrieval System (AIRS) or State Implementation Plans (SIP) area source methodologies and to develop appropriate emissions estimation methodologies and emission factors for a group of these source categories. Based on the results of the identification and characterization portions of the research, five source categories were selected for methodology and emission factor development: catastrophic/accidental releases, vehicle repair facilities, recycling, pesticide application and agricultural operations. The report presents emissions estimation methodologies and emission factor data for the selected source categories. The discussions for each selected category include general background information, emissions generation activities, pollutants emitted, sources of activity and pollutant data, emissions estimation methodologies, issues to be considered and recommendations. The information used in these discussions was derived from various sources including available literature, industrial and trade association publications and contracts, experts on the category and activity, and knowledgeable federal and state personnel

Photon statistics characterization of a single-photon source

International Nuclear Information System (INIS)

Alleaume, R; Treussart, F; Courty, J-M; Roch, J-F

2004-01-01

In a recent experiment, we reported the time-domain intensity noise measurement of a single-photon source relying on single-molecule fluorescence control. In this paper, we present data processing starting from photocount timestamps. The theoretical analytical expression of the time-dependent Mandel parameter Q(T) of an intermittent single-photon source is derived from ON↔OFF dynamics. Finally, source intensity noise analysis, using the Mandel parameter, is quantitatively compared with the usual approach relying on the time autocorrelation function, both methods yielding the same molecular dynamical parameters

Comparative study of two drying techniques used in radioactive source preparation: Freeze-drying and evaporation using hot dry nitrogen jets

International Nuclear Information System (INIS)

Branger, T.; Bobin, C.; Iroulart, M.-G.; Lepy, M.-C.; Le Garreres, I.; Morelli, S.; Lacour, D.; Plagnard, J.

2008-01-01

Quantitative solid sources are used widely in the field of radionuclide metrology. With the aim to improve the detection efficiency for electrons and x-rays, a comparative study between two source drying techniques has been undertaken at LNE-Laboratoire National Henri Becquerel (LNE-LNHB, France). In this paper, freeze-drying using commercial equipment is compared with a system of drying using hot jets of nitrogen developed at Institute for Reference Materials and Measurements (IRMM, Belgium). In order to characterize the influence of self-absorption, the detection efficiencies for 51 Cr sources have been measured by coincidence counting and photon spectrometry

Open-Source Data and the Study of Homicide.

Science.gov (United States)

Parkin, William S; Gruenewald, Jeff

2015-07-20

To date, no discussion has taken place in the social sciences as to the appropriateness of using open-source data to augment, or replace, official data sources in homicide research. The purpose of this article is to examine whether open-source data have the potential to be used as a valid and reliable data source in testing theory and studying homicide. Official and open-source homicide data were collected as a case study in a single jurisdiction over a 1-year period. The data sets were compared to determine whether open-sources could recreate the population of homicides and variable responses collected in official data. Open-source data were able to replicate the population of homicides identified in the official data. Also, for every variable measured, the open-sources captured as much, or more, of the information presented in the official data. Also, variables not available in official data, but potentially useful for testing theory, were identified in open-sources. The results of the case study show that open-source data are potentially as effective as official data in identifying individual- and situational-level characteristics, provide access to variables not found in official homicide data, and offer geographic data that can be used to link macro-level characteristics to homicide events. © The Author(s) 2015.

A novel full scale experimental characterization of wind turbine aero-acoustic noise sources - preliminary results

DEFF Research Database (Denmark)

Aagaard Madsen, Helge; Bertagnolio, Franck; Fischer, Andreas

2016-01-01

of the blade and the noise on the ground in a distance of about one rotor diameter. In total six surface microphones were used to measure the SP at the leading edge (LE) and trailing edge (TE) of the blade. In parallel noise was measured by eight microphones placed on plates on the ground around the turbine......The paper describes a novel full scale experiment on a 500 kW wind turbine with the main objective to characterize the aero-acoustic noise sources. The idea behind the instrumentation is to study the link and correlation between the surface pressure (SP) fluctuations in the boundary layer...... in equidistant angles on a circle with a radius of about one rotor diameter. The data were analyzed in segments of 2.2 s which is the time for one rotor revolution. The spectra for the TE microphones on the suction side of the blade show a characteristic roll-off pattern around a frequency of 600-700 Hz...

Reliability of MEG source imaging of anterior temporal spikes: analysis of an intracranially characterized spike focus.

Science.gov (United States)

Wennberg, Richard; Cheyne, Douglas

2014-05-01

To assess the reliability of MEG source imaging (MSI) of anterior temporal spikes through detailed analysis of the localization and orientation of source solutions obtained for a large number of spikes that were separately confirmed by intracranial EEG to be focally generated within a single, well-characterized spike focus. MSI was performed on 64 identical right anterior temporal spikes from an anterolateral temporal neocortical spike focus. The effects of different volume conductors (sphere and realistic head model), removal of noise with low frequency filters (LFFs) and averaging multiple spikes were assessed in terms of the reliability of the source solutions. MSI of single spikes resulted in scattered dipole source solutions that showed reasonable reliability for localization at the lobar level, but only for solutions with a goodness-of-fit exceeding 80% using a LFF of 3 Hz. Reliability at a finer level of intralobar localization was limited. Spike averaging significantly improved the reliability of source solutions and averaging 8 or more spikes reduced dependency on goodness-of-fit and data filtering. MSI performed on topographically identical individual spikes from an intracranially defined classical anterior temporal lobe spike focus was limited by low reliability (i.e., scattered source solutions) in terms of fine, sublobar localization within the ipsilateral temporal lobe. Spike averaging significantly improved reliability. MSI performed on individual anterior temporal spikes is limited by low reliability. Reduction of background noise through spike averaging significantly improves the reliability of MSI solutions. Copyright © 2013 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Characterization of polarized electrons coming from helium post-discharge source; Caracterisation du faisceau d`electrons polarises issus d`une source a post-decharge d`helium

Energy Technology Data Exchange (ETDEWEB)

Zerhouni, R.O.

1996-02-01

The objective of this thesis is the characterization of the polarized electron source developed at Orsay and foreseen to be coupled to a cw accelerator for nuclear physics experiments. The principle of operation of this source relies on the chemo-ionization reaction between optically aligned helium triplet metastable atoms and CO{sub 2} molecules. The helium metastable atoms are generated by injection of purified helium into a 2,45 GHz micro-wave discharge. They are optically pumped using two beams of 1,083 micro-meter resonant radiation, one circularly and the other linearly polarized. Both beams are delivered by a high power LNA laser. The metastable atomic beam interacts with a dense (10{sup 13} cm {sup -3}) spin singlet CO{sub 2} target. A fraction of the produced polarized electrons is extracted and collimated by electrostatic optics. Either to the Mott polarimeter or to the Faraday cup in order to measure the electron polarization and extracted current. For current intensities of 100 micro-Amperes, the electronic polarization reaches 62 % and shows that this type of source has reached the same high competitive level as the most performing GaAs ones. Additionally, the optical properties of the extracted beam are found to be excellent. These properties (energy spread and emittance) reflect the electron energy distribution at the chemo-ionization region. The upper limit of the beam`s energy spread is 0.24 eV since this value characterizes our instrumental resolution. The average normalized emittance is found to be 0.6 pi mm-mrad. These values satisfy the requirements of most cw accelerators. All the measurements were performed at low electron beam transport energies (1 to 2 KeV). (author). 105 refs., 54 figs., 4 tabs.

CHARACTERIZATION OF NITROUS OXIDE EMISSION SOURCES

Science.gov (United States)

The report presents a global inventory of nitrous oxide (N2O) based on reevaluation of previous estimates and additions of previously uninventoried source categories. (NOTE: N2O is both a greenhouse gas and a precursor of nitric oxide (NO) which destroys stratospheric ozone.) The...

Source characterization of major emission sources in the Imperial and Mexicali Valleys along the US/Mexico border

Energy Technology Data Exchange (ETDEWEB)

Watson, J.G.; Chow, J.C. [Desert Research Institute, 2215 Raggio Pkwy., 89512 Reno, NV (United States)

2001-08-10

Chemical profiles for particle emissions are needed for source apportionment studies using the chemical mass balance (CMB) receptor model. Source measurements of geological sources, motor vehicle exhaust, vegetative burning (e.g. asparagus, field burning, charbroil cooking), and industrial sources (e.g. oil-fueled glass plant, manure-fueled power plants) were acquired as part of the Imperial/Mexicali Valley Cross Border PM{sub 10} Transport Study in 1992. Six different source sampling techniques (i.e. hot- and diluted-exhaust sampling, ground-based source sampling, particle sweeping/grab sampling, vacuum sampling, and laboratory resuspension sampling) were applied to acquire filter samples of PM{sub 2.5} and PM{sub 10} (particulate matter with aerodynamic diameters <2.5 and 10 {mu}m, respectively). Filter samples were analyzed for mass by gravimetry, elements (Na to U) by X-ray fluorescence, anions (Cl{sup -}, NO{sub 3}{sup -}, SO{sub 4}{sup =}) by ion chromatography, ammonium (NH{sub 4}{sup +}) by automated colorimetry, soluble sodium (Na{sup +}) and potassium (K{sup +}) by atomic absorption spectrophotometry, and organic and elemental carbon (OC, EC) by thermal/optical reflectance. Concentration data were acquired for a total of 50 chemical species. Elevated abundances of crustal components (Al, Si, K, Ca, Fe) from geological material, carbon (OC, EC) and trace elements (Br, Pb) from vehicle exhausts, carbon (OC, EC) and ions (K{sup +}, Cl{sup -}) from vegetative burning, ions (SO{sub 4}{sup =}, NH{sub 4}{sup +}, Na{sup +}, K{sup +}, Cl{sup -}) and elements (Cl, Se) from a manure-fueled power plants, and sulfur and trace elements (Na{sup +}, Pb, Se, Ni, V) from an oil-fueled glass plant were found in the resulting source profiles. Abundances of crustal species (e.g. Al, Si, Ca) in the Imperial/Mexicali Valley geological profiles are more than twice those found in central and southern California. Abundances of lead in motor vehicle exhausts indicate different

Volumetric plasma source development and characterization

International Nuclear Information System (INIS)

Crain, Marlon D.; Maron, Yitzhak; Oliver, Bryan Velten; Starbird, Robert L.; Johnston, Mark D.; Hahn, Kelly Denise; Mehlhorn, Thomas Alan; Droemer, Darryl W.

2008-01-01

The development of plasma sources with densities and temperatures in the 10 15 -10 17 cm -3 and 1-10eV ranges which are slowly varying over several hundreds of nanoseconds within several cubic centimeter volumes is of interest for applications such as intense electron beam focusing as part of the x-ray radiography program. In particular, theoretical work (1,2) suggests that replacing neutral gas in electron beam focusing cells with highly conductive, pre-ionized plasma increases the time-averaged e-beam intensity on target, resulting in brighter x-ray sources. This LDRD project was an attempt to generate such a plasma source from fine metal wires. A high voltage (20-60kV), high current (12-45kA) capacitive discharge was sent through a 100 (micro)m diameter aluminum wire forming a plasma. The plasma's expansion was measured in time and space using spectroscopic techniques. Lineshapes and intensities from various plasma species were used to determine electron and ion densities and temperatures. Electron densities from the mid-10 15 to mid-10 16 cm -3 were generated with corresponding electron temperatures of between 1 and 10eV. These parameters were measured at distances of up to 1.85 cm from the wire surface at times in excess of 1 (micro)s from the initial wire breakdown event. In addition, a hydrocarbon plasma from surface contaminants on the wire was also measured. Control of these contaminants by judicious choice of wire material, size, and/or surface coating allows for the ability to generate plasmas with similar density and temperature to those given above, but with lower atomic masses

Characterizing and controlling industrial dust: a case study in small particle measurement.

Science.gov (United States)

Combes, Richard S; Warren, D Alan

2005-07-01

Instrumentation used to measure characteristics of fine particles entrained in gas or suspended in aerosols provides information needed to develop valid regulations for emission sources and to support the design of control technologies. This case study offers a brief history of "micromeritics," a term used by early researchers to describe the science of small particles, and the related invention of laboratory instruments for characterizing very fine particles. The historical view provides insights into the role that Progressive Era government agencies played in advancing esoteric science and applying this knowledge to the regulation of workplace air pollution. Micromeritics instrumentation developed in conjunction with federal research now has many commercial applications worldwide, with characterizing airborne pollutants only a minor one. However, the continuing advances in the micromeritics field provide important laboratory measurement capabilities to environmental research organizations, such as the National Institute for Occupational Safety and Health (NIOSH).

Estudo e caracterização da zeólita OFF Tipo T empregando diferentes fontes de silício Study and characterization of zeolite Offretite Type T employing differents silicon sources

Directory of Open Access Journals (Sweden)

Alessandra Caovilla

2009-01-01

Full Text Available Offretite T zeolite was synthesized using different source of Si (Ludox AS-30, Ludox LS-30 and Aerosil 200 Degussa. The obtained materials were characterized by different complementary techniques: XRD, textural analysis by N2 adsorption, IV, SEM and chemistry analysis. This zeolite has an intermediary structure between offretite and erionite zeolites. In all experiments offretite T phase was obtained. Offretite phase presenting better crystalility are obtained in synthesis with stirring and employing aerosil as silicon source. This zeolite presents a potencial application as catalyst for hydroisodewaxing process.

Thermal neutron source study

International Nuclear Information System (INIS)

Holden, T.M.

1983-05-01

The value of intense neutron beams for condensed matter research is discussed with emphasis on the complementary nature of steady state and pulsed neutron sources. A large body of information on neutron sources, both existing and planned, is then summarized under four major headings: fission reactors, electron accelerators with heavy metal targets, pulsed spallation sources and 'steady state' spallation sources. Although the cost of a spallation source is expected to exceed that of a fission reactor of the same flux by a factor of two, there are significant advantages for a spallation device such as the proposed Electronuclear Materials Test Facility (EMTF)

Production and characterization of polyhydroxybutyrate from Vibrio harveyi MCCB 284 utilizing glycerol as carbon source.

Science.gov (United States)

Mohandas, S P; Balan, L; Lekshmi, N; Cubelio, S S; Philip, R; Bright Singh, I S

2017-03-01

Production and characterization of polyhydroxybutyrate (PHB) from moderately halophilic bacterium Vibrio harveyi MCCB 284 isolated from tunicate Phallusia nigra. Twenty-five bacterial isolates were obtained from tunicate samples and three among them exhibited an orange fluorescence in Nile red staining indicating the presence of PHB. One of the isolates, MCCB 284, which showed rapid growth and good polymer yield, was identified as V. harveyi. The optimum conditions of the isolate for the PHB production were pH 8·0, sodium chloride concentration 20 g l -1 , inoculum size 0·5% (v/v), glycerol 20 g l -1 and 72 h of incubation at 30°C. Cell dry weight (CDW) of 3·2 g l -1 , PHB content of 2·3 g l -1 and final PHB yield of 1·2 g l -1 were achieved. The extracted PHB was characterized by FTIR, NMR and DSC-TGA techniques. An isolate of V. harveyi that could effectively utilize glycerol for growth and PHB accumulation was obtained from tunicate P. nigra. PHB produced was up to 72% based on CDW. This is the first report of an isolate of V. harveyi which utilizes glycerol as the sole carbon source for PHB production with high biomass yield. This isolate could be of use as candidate species for commercial PHB production using glycerol as the feed stock or as source of genes for recombinant PHB production or for synthetic biology. © 2016 The Society for Applied Microbiology.

Proton beam characterization by proton-induced acoustic emission: simulation studies

International Nuclear Information System (INIS)

Jones, K C; Witztum, A; Avery, S; Sehgal, C M

2014-01-01

Due to their Bragg peak, proton beams are capable of delivering a targeted dose of radiation to a narrow volume, but range uncertainties currently limit their accuracy. One promising beam characterization technique, protoacoustic range verification, measures the acoustic emission generated by the proton beam. We simulated the pressure waves generated by proton radiation passing through water. We observed that the proton-induced acoustic signal consists of two peaks, labeled α and γ, with two originating sources. The α acoustic peak is generated by the pre-Bragg peak heated region whereas the source of the γ acoustic peak is the proton Bragg peak. The arrival time of the α and γ peaks at a transducer reveals the distance from the beam propagation axis and Bragg peak center, respectively. The maximum pressure is not observed directly above the Bragg peak due to interference of the acoustic signals. Range verification based on the arrival times is shown to be more effective than determining the Bragg peak position based on pressure amplitudes. The temporal width of the α and γ peaks are linearly proportional to the beam diameter and Bragg peak width, respectively. The temporal separation between compression and rarefaction peaks is proportional to the spill time width. The pressure wave expected from a spread out Bragg peak dose is characterized. The simulations also show that acoustic monitoring can verify the proton beam dose distribution and range by characterizing the Bragg peak position to within ∼1 mm. (paper)

Seasonal and spatial variation of trace elements and metals in quasi-ultrafine (PM0.25) particles in the Los Angeles metropolitan area and characterization of their sources

International Nuclear Information System (INIS)

Saffari, Arian; Daher, Nancy; Shafer, Martin M.; Schauer, James J.; Sioutas, Constantinos

2013-01-01

Year-long sampling campaign of quasi-ultrafine particles (PM 0.25 ) was conducted at 10 distinct locations across the Los Angeles south coast air basin and concentrations of trace elements and metals were quantified at each site using high-resolution inductively coupled plasma sector field mass spectrometry. In order to characterize sources of trace elements and metals, principal component analysis (PCA) was applied to the dataset. The major sources were identified as road dust (influenced by vehicular emissions as well as re-suspended soil), vehicular abrasion, residual oil combustion, cadmium sources and metal plating. These sources altogether accounted for approximately 85% of the total variance of quasi-ultrafine elemental content. The concentrations of elements originating from source and urban locations generally displayed a decline as we proceeded from the coast to the inland. Occasional concentration peaks in the rural receptor sites were also observed, driven by the dominant westerly/southwesterly wind transporting the particles to the receptor areas. -- Highlights: •We collected quasi-ultrafine samples at 10 locations across the Los Angeles Basin. •The concentration of trace elements and metals at each site were quantified. •Distinct temporal and spatial variability was observed across the basin. •Principal component analysis was applied to the data to characterize the sources. •Five major sources were identified for quasi-ultrafine elemental content. -- Characterization of sources of trace elements and metals in quasi-ultrafine particles in the Los Angeles south coast air basin and explaining their seasonal and spatial variability

Time-Reversal Study of the Hemet (CA) Tremor Source

Science.gov (United States)

Larmat, C. S.; Johnson, P. A.; Guyer, R. A.

2010-12-01

Since its first observation by Nadeau & Dolenc (2005) and Gomberg et al. (2008), tremor along the San Andreas fault system is thought to be a probe into the frictional state of the deep part of the fault (e.g. Shelly et al., 2007). Tremor is associated with slow, otherwise deep, aseismic slip events that may be triggered by faint signals such as passing waves from remote earthquakes or solid Earth tides.Well resolved tremor source location is key to constrain frictional models of the fault. However, tremor source location is challenging because of the high-frequency and highly-scattered nature of tremor signal characterized by the lack of isolated phase arrivals. Time Reversal (TR) methods are emerging as a useful tool for location. The unique requirement is a good velocity model for the different time-reversed phases to arrive coherently onto the source point. We present results of location for a tremor source near the town of Hemet, CA, which was triggered by the 2002 M 7.9 Denali Fault earthquake (Gomberg et al., 2008) and by the 2009 M 6.9 Gulf of California earthquake. We performed TR in a volume model of 88 (N-S) x 70 (W-E) x 60 km (Z) using the full-wave 3D wave-propagation package SPECFEM3D (Komatitsch et al., 2002). The results for the 2009 episode indicate a deep source (at about 22km) which is about 4km SW the fault surface scarp. We perform STA/SLA and correlation analysis in order to have independent confirmation of the Hemet tremor source. We gratefully acknowledge the support of the U. S. Department of Energy through the LANL/LDRD Program for this work.

Source characterization of underground explosions from hydrodynamic-to-elastic coupling simulations

Science.gov (United States)

Chiang, A.; Pitarka, A.; Ford, S. R.; Ezzedine, S. M.; Vorobiev, O.

2017-12-01

A major improvement in ground motion simulation capabilities for underground explosion monitoring during the first phase of the Source Physics Experiment (SPE) is the development of a wave propagation solver that can propagate explosion generated non-linear near field ground motions to the far-field. The calculation is done using a hybrid modeling approach with a one-way hydrodynamic-to-elastic coupling in three dimensions where near-field motions are computed using GEODYN-L, a Lagrangian hydrodynamics code, and then passed to WPP, an elastic finite-difference code for seismic waveform modeling. The advancement in ground motion simulation capabilities gives us the opportunity to assess moment tensor inversion of a realistic volumetric source with near-field effects in a controlled setting, where we can evaluate the recovered source properties as a function of modeling parameters (i.e. velocity model) and can provide insights into previous source studies on SPE Phase I chemical shots and other historical nuclear explosions. For example the moment tensor inversion of far-field SPE seismic data demonstrated while vertical motions are well-modeled using existing velocity models large misfits still persist in predicting tangential shear wave motions from explosions. One possible explanation we can explore is errors and uncertainties from the underlying Earth model. Here we investigate the recovered moment tensor solution, particularly on the non-volumetric component, by inverting far-field ground motions simulated from physics-based explosion source models in fractured material, where the physics-based source models are based on the modeling of SPE-4P, SPE-5 and SPE-6 near-field data. The hybrid modeling approach provides new prospects in modeling explosion source and understanding the uncertainties associated with it.

Development of a High Fluence Neutron Source for Nondestructive Characterization of Nuclear Waste

International Nuclear Information System (INIS)

Pickrell, Mark M.

1999-01-01

We are addressing the need to measure nuclear wastes, residues, and spent fuel in order to process these for final disposition. For example, TRU wastes destined for the WIPP must satisfy extensive characterization criteria outlined in the Waste Acceptance Criteria, the Quality Assurance Program Plan, and the Performance Demonstration Plan. Similar requirements exist for spent fuel and residues. At present, no nondestructive assay (NDA) instrumentation is capable of satisfying all of the PDP test cycles (particularly for Remote-Handled TRU waste). One of the primary methods for waste assay is by active neutron interrogation. The objective of this project is to improve the capability of all active neutron systems by providing a higher intensity neutron source (by about a factor of 1,000) for essentially the same cost, power, and space requirements as existing systems. This high intensity neutron source is an electrostatically confined (IEC) plasma device. The IEC is a symmetric sphere that was originally developed in the 1960s as a possible fusion reactor. It operates as DT neutron generator. Although it is not likely that this device will scale to fusion reactor levels, previous experiments1 have demonstrated a neutron yield of 2 x 1010 neutrons/second on a table-top device that can be powered from ordinary laboratory circuits (9 kilowatts). Subsequently, the IEC physics has been extensively studied at the University of Illinois and other locations. We have established theoretically the basis for scaling the output up to 1 x 1011 neutrons/second. In addition, IEC devices have run for cumulative times approaching 10,000 hours, which is essential for practical application to NDA. They have been operated in pulsed and continuous mode. The essential features of the IEC plasma neutron source, compared to existing sources of the same cost, size and power consumption, are: Table 1: Present and Target Operating Parameters for Small Neutron Generators Parameter Present IEC

Characterization of germanium linear kinoform lenses at Diamond Light Source.

Science.gov (United States)

Alianelli, L; Sawhney, K J S; Tiwari, M K; Dolbnya, I P; Stevens, R; Jenkins, D W K; Loader, I M; Wilson, M C; Malik, A

2009-05-01

The unprecedented brilliance achieved by third-generation synchrotron sources and the availability of improved optics have opened up new opportunities for the study of materials at the micrometre and nanometre scale. Focusing the synchrotron radiation to smaller and smaller beams is having a huge impact on a wide research area at synchrotrons. The key to the exploitation of the improved sources is the development of novel optics that deliver narrow beams without loss of brilliance and coherence. Several types of synchrotron focusing optics are successfully fabricated using advanced miniaturization techniques. Kinoform refractive lenses are being developed for hard X-ray beamlines, and the first test results at Diamond are discussed in this paper.

Assessing the joint impact of DNAPL source-zone behavior and degradation products on the probabilistic characterization of human health risk

Science.gov (United States)

Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

2016-02-01

The release of industrial contaminants into the subsurface has led to a rapid degradation of groundwater resources. Contamination caused by Dense Non-Aqueous Phase Liquids (DNAPLs) is particularly severe owing to their limited solubility, slow dissolution and in many cases high toxicity. A greater insight into how the DNAPL source zone behavior and the contaminant release towards the aquifer impact human health risk is crucial for an appropriate risk management. Risk analysis is further complicated by the uncertainty in aquifer properties and contaminant conditions. This study focuses on the impact of the DNAPL release mode on the human health risk propagation along the aquifer under uncertain conditions. Contaminant concentrations released from the source zone are described using a screening approach with a set of parameters representing several scenarios of DNAPL architecture. The uncertainty in the hydraulic properties is systematically accounted for by high-resolution Monte Carlo simulations. We simulate the release and the transport of the chlorinated solvent perchloroethylene and its carcinogenic degradation products in randomly heterogeneous porous media. The human health risk posed by the chemical mixture of these contaminants is characterized by the low-order statistics and the probability density function of common risk metrics. We show that the zone of high risk (hot spot) is independent of the DNAPL mass release mode, and that the risk amplitude is mostly controlled by heterogeneities and by the source zone architecture. The risk is lower and less uncertain when the source zone is formed mostly by ganglia than by pools. We also illustrate how the source zone efficiency (intensity of the water flux crossing the source zone) affects the risk posed by an exposure to the chemical mixture. Results display that high source zone efficiencies are counter-intuitively beneficial, decreasing the risk because of a reduction in the time available for the production

Studies and modeling of cold neutron sources

International Nuclear Information System (INIS)

Campioni, G.

2004-11-01

With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources

Size-Resolved Characterization of Particles and Fibers Released during Abrasion of Fiber-Reinforced Composite in a Workplace Influenced by Ambient Background Sources

DEFF Research Database (Denmark)

Kling, Kirsten I.; Levin, Marcus; Jensen, Alexander C. O.

2016-01-01

We demonstrate the use of high-to low-resolution microscopy and particle chemical analysis during normal vacuum and cryo-conditions to identify the nature and relative abundances of process-generated particles and fibers from sanding of a glass and carbon fiber epoxy layer-composite in a workplace...... influenced by both indoor and ambient background sources. The study suggests that a proper exposure characterization requires multiple techniques covering wide size ranges to reach a conclusion. Besides a rise in number concentration due to release of particles during the sanding, a significant contribution...

Lattice Study for the Taiwan Photon Source

CERN Document Server

Kuo, Chin-Cheng; Chen Chien Te; Luo, Gwo-Huei; Tsai, Hung-Jen; Wang, Min-Huey

2005-01-01

The feasibility study for the new 3.0~3.3 GeV Taiwan synchrotron light source, dubbed Taiwan Photon Source, was initiated in July, 2004. The goal is to construct a high performance light source with extremely bright X-ray in complementary to the existing 1.5 GeV light source in Taiwan. The ring circumference is 518.4 m and a 24-cell DBA lattice structure is chosen. The natural emittance with distributed dispersion is less than 2 nm-rad. A large booster ring of 499.2 m sharing the storage ring tunnel will be adopted.

Study of the general plasma characteristics of a high power multifilament ion source

International Nuclear Information System (INIS)

Schoenberg, K.F.

1979-09-01

A general assessment of the steady state and time dependent plasma properties which characterize a high power multifilament ion source is presented. Steady state measurements, obtained via a pulsed electrostatic probe data acquisition system, are described. Fluctuation measurements, obtained via a broadband digital spectral analysis system, are also given

Neutron source characterization for materials experiments

International Nuclear Information System (INIS)

Greenwood, L.R.

1982-01-01

Data are presented from HFIR-CTR32, EBRII-X287, and the Omega West Reactor. An important new source of damage in nickel arises from the 340 keV 56 Fe recoil from the 59 Ni(n,α) reaction used to produce high helium levels in materials irradiations in a thermal spectrum. The status of all other experiments is summarized

42 CFR 456.244 - Data sources for studies.

Science.gov (United States)

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Data sources for studies. 456.244 Section 456.244 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES...: Medical Care Evaluation Studies § 456.244 Data sources for studies. Data that the committee uses to...

42 CFR 456.144 - Data sources for studies.

Science.gov (United States)

2010-10-01

... 42 Public Health 4 2010-10-01 2010-10-01 false Data sources for studies. 456.144 Section 456.144 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Care Evaluation Studies § 456.144 Data sources for studies. Data that the committee uses to perform...

Pb isotopic composition of the atmosphere of the Sao Paulo city, Brazil, and isotopic characterization of some pollutant sources

International Nuclear Information System (INIS)

Aily, C.; Babinski, M.; Ruiz, I.R.; Sato, K

2001-01-01

Lead isotopes are known to be good tools for surveying lead origin in atmospheric samples (Chow et al., 1975). Lead has four naturally occurring stable isotopes: 206 Pb, 207 Pb, 208 Pb and 204 Pb. The first three isotopes are end products of radioactive decay chains from 238 U, 235 U and 232 Th, respectively, and the last one is non-radiogenic. Therefore, their abundance and the ratios among the four isotopes gradually change with time. Lead in the atmosphere comes from various sources, such as leaded gasoline, industrial emissions and coal combustion. Thus, lead isotope ratios different from those of the mother rock in the region are often observed in the atmosphere (Tatsumoto and Patterson, 1963). Lead is emitted to the atmosphere in fine particles, which can be transported within air masses for very long distances, e. g. from mid latitude regions to the Artic and Antarctica (Sturges and Barrie, 1989). Lead isotopes have been used to trace the pollutant sources in many cities of the world. However, a systematic study using this methodology has not been done in any Brazilian city. The main purpose of the present work is to characterize the Pb isotope composition in the atmosphere in Sao Paulo city, and suggest the possible pollutant sources. For our study lead isotopes were measured in different samples: aerosols and rainwater which would yield the Pb isotope composition of the atmosphere. Samples of gasoline and ethanol, gutter sweepings, soot from vehicle exhaust pipes, and filters containing particulate material from industrial emissions were also analyzed, since they were considered potential pollutant sources of the atmosphere. In order to obtain the local geogenic Pb isotopic composition we also analyzed rock and K-feldspar samples. Lead concentrations were only determined on aerosols and rainwater samples (au)

EchoSeed Model 6733 Iodine-125 brachytherapy source: Improved dosimetric characterization using the MCNP5 Monte Carlo code

Energy Technology Data Exchange (ETDEWEB)

Mosleh-Shirazi, M. A.; Hadad, K.; Faghihi, R.; Baradaran-Ghahfarokhi, M.; Naghshnezhad, Z.; Meigooni, A. S. [Center for Research in Medical Physics and Biomedical Engineering and Physics Unit, Radiotherapy Department, Shiraz University of Medical Sciences, Shiraz 71936-13311 (Iran, Islamic Republic of); Radiation Research Center and Medical Radiation Department, School of Engineering, Shiraz University, Shiraz 71936-13311 (Iran, Islamic Republic of); Comprehensive Cancer Center of Nevada, Las Vegas, Nevada 89169 (United States)

2012-08-15

This study primarily aimed to obtain the dosimetric characteristics of the Model 6733 {sup 125}I seed (EchoSeed) with improved precision and accuracy using a more up-to-date Monte-Carlo code and data (MCNP5) compared to previously published results, including an uncertainty analysis. Its secondary aim was to compare the results obtained using the MCNP5, MCNP4c2, and PTRAN codes for simulation of this low-energy photon-emitting source. The EchoSeed geometry and chemical compositions together with a published {sup 125}I spectrum were used to perform dosimetric characterization of this source as per the updated AAPM TG-43 protocol. These simulations were performed in liquid water material in order to obtain the clinically applicable dosimetric parameters for this source model. Dose rate constants in liquid water, derived from MCNP4c2 and MCNP5 simulations, were found to be 0.993 cGyh{sup -1} U{sup -1} ({+-}1.73%) and 0.965 cGyh{sup -1} U{sup -1} ({+-}1.68%), respectively. Overall, the MCNP5 derived radial dose and 2D anisotropy functions results were generally closer to the measured data (within {+-}4%) than MCNP4c and the published data for PTRAN code (Version 7.43), while the opposite was seen for dose rate constant. The generally improved MCNP5 Monte Carlo simulation may be attributed to a more recent and accurate cross-section library. However, some of the data points in the results obtained from the above-mentioned Monte Carlo codes showed no statistically significant differences. Derived dosimetric characteristics in liquid water are provided for clinical applications of this source model.

Characterization, Distribution, Sources and Origins of Aliphatic Hydrocarbons from Surface Sediment of Prai Strait, Penang, Malaysia: A Widespread Anthropogenic Input

Directory of Open Access Journals (Sweden)

Mahyar Sakari

2008-07-01

Full Text Available Persistent organic pollutants such as petroleum hydrocarbons are one of the most serious and important class of pollutants that face to many countries including Malaysia. Aliphatic hydrocarbons contain straight chain alkane; derive from anthropogenic and natural sources to the marine environment. The multi-purpose strait of Prai is located in the Northwest of Peninsular Malaysia plays an important economic role in the Southeast Asia. Twenty surface sediment samples were collected using Eckman dredge to measure the concentration and determine the characterization, sources and origins of the aliphatic hydrocarbons in December 2006. Samples (top 4 cm were extracted with Soxhlet, treated with activated copper and subjected to 2 steps column chromatography for purification and fractionation. Alkane fraction injected into Gas Chromatography–Flame Ionization Detector (GC-FID for instrumental analysis. The results showed that total n-alkane concentrations are ranging from 512 to 10770 ng/mg d. w. Carbon Preferences Index (CPI revealed an extreme widespread anthropogenic input and naturally derived (CPI= 0 to 4.88 hydrocarbons in the study area. The ratio of C31/C19 indicated that natural hydrocarbons are generating from terrestrial vascular plants and transferring by rivers. The characteristics of Major Hydrocarbons provided evidences that oil and its derivatives either fresh or degraded are the major contributors of the pollution in the study area. Statistical approaches also confirmed that 85% of study area affected by oil sources of pollution. It is seen that aliphatic hydrocarbons mostly transfer by lateral input to the marine environment than atmospheric movements.

Noise characterization of silicon strip detectors-comparison of sensors with and without integrated jfet source-follower.

CERN Document Server

Giacomini, Gabriele

Noise is often the main factor limiting the performance of detector systems. In this work a detailed study of the noise contributions in different types of silicon microstrip sensors is carried on. We investigate three sensors with double-sided readout fabricated by different suppliers for the ALICE experiment at the CERN LHC, in addition to detectors including an integrated JFET Source-Follower as a first signal conditioning stage. The latter have been designed as an attempt at improving the performance when very long strips, obtained by gangling together several sensors, are required. After a description of the strip sensors and of their operation, the “static” characterization measurements performed on them (current and capacitance versus voltage and/or frequency) are illustrated and interpreted. Numerical device simulation has been employed as an aid in interpreting some of the measurement results. The commonly used models for expressing the noise of the detector-amplifier system in terms of its relev...

Characterizations and rheological study of the purified polysaccharide extracted from quince seeds

DEFF Research Database (Denmark)

Rezagholi, Fatemeh; Hashemi, Seyed Mohammad Bagher; Gholamhosseinpour, Aliakbar

2018-01-01

The functional characteristics of hydrocolloids are mainly dependent on their physicochemical properties. Thus, it is essential to characterize the new sources of hydrocolloids. Quince seed gum (QSG) is a high molecular weight polysaccharide (9.61×106 g/mol) composed of 85.04±2.87% carbohydrate (...

Characterization of Crystallographic Structures Using Bragg-Edge Neutron Imaging at the Spallation Neutron Source

Directory of Open Access Journals (Sweden)

Gian Song

2017-12-01

Full Text Available Over the past decade, wavelength-dependent neutron radiography, also known as Bragg-edge imaging, has been employed as a non-destructive bulk characterization method due to its sensitivity to coherent elastic neutron scattering that is associated with crystalline structures. Several analysis approaches have been developed to quantitatively determine crystalline orientation, lattice strain, and phase distribution. In this study, we report a systematic investigation of the crystal structures of metallic materials (such as selected textureless powder samples and additively manufactured (AM Inconel 718 samples, using Bragg-edge imaging at the Oak Ridge National Laboratory (ORNL Spallation Neutron Source (SNS. Firstly, we have implemented a phenomenological Gaussian-based fitting in a Python-based computer called iBeatles. Secondly, we have developed a model-based approach to analyze Bragg-edge transmission spectra, which allows quantitative determination of the crystallographic attributes. Moreover, neutron diffraction measurements were carried out to validate the Bragg-edge analytical methods. These results demonstrate that the microstructural complexity (in this case, texture plays a key role in determining the crystallographic parameters (lattice constant or interplanar spacing, which implies that the Bragg-edge image analysis methods must be carefully selected based on the material structures.

The Chandra Source Catalog : Automated Source Correlation

Science.gov (United States)

Hain, Roger; Evans, I. N.; Evans, J. D.; Glotfelty, K. J.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Grier, J. D.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McCollough, M. L.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Primini, F. A.; Refsdal, B. L.; Rots, A. H.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; Van Stone, D. W.; Winkelman, S. L.; Zografou, P.

2009-01-01

Chandra Source Catalog (CSC) master source pipeline processing seeks to automatically detect sources and compute their properties. Since Chandra is a pointed mission and not a sky survey, different sky regions are observed for a different number of times at varying orientations, resolutions, and other heterogeneous conditions. While this provides an opportunity to collect data from a potentially large number of observing passes, it also creates challenges in determining the best way to combine different detection results for the most accurate characterization of the detected sources. The CSC master source pipeline correlates data from multiple observations by updating existing cataloged source information with new data from the same sky region as they become available. This process sometimes leads to relatively straightforward conclusions, such as when single sources from two observations are similar in size and position. Other observation results require more logic to combine, such as one observation finding a single, large source and another identifying multiple, smaller sources at the same position. We present examples of different overlapping source detections processed in the current version of the CSC master source pipeline. We explain how they are resolved into entries in the master source database, and examine the challenges of computing source properties for the same source detected multiple times. Future enhancements are also discussed. This work is supported by NASA contract NAS8-03060 (CXC).

Characterization and treatment of water used for human consumption from six sources located in the Cameron/Tuba City abandoned uranium mining area.

Science.gov (United States)

Orescanin, Visnja; Kollar, Robert; Nad, Karlo; Mikelic, Ivanka Lovrencic; Kollar, Iris

2011-01-01

The purpose of this research was the characterization and improvement of the quality of water used for human consumption of unregulated/regulated water sources located in the Cameron/Tuba City abandoned uranium mining area (NE Arizona, western edge of the Navajo Nation). Samples were collected at six water sources which included regulated sources: Wind Mill (Tank 3T-538), Badger Springs and Paddock Well as well as unregulated sources: Willy Spring, Water Wall and Water Hole. Samples taken from Wind Mill, Water Wall and Water Hole were characterized with high turbidity and color as well as high level of manganese, iron and nickel and elevated value of molybdenum. High level of iron was also found in Badger Spring, Willy Spring, and Paddock Well. These three water sources were also characterized with elevated values of fluoride and vanadium. Significant amounts of zinc were found in Water Wall and Water Hole samples. Water Wall sample was also characterized with high level of Cr(VI). Compared to primary or secondary Navajo Nation Environmental Protection Agency (NNEPA) water quality standard the highest enrichment was found for turbidity (50.000 times), color (up to 1.796 times) and manganese (71 times), Cr(VI) (17.5 times), iron (7.4 times) and arsenic (5.2 times). Activities of (226)Ra and (238)U in water samples were still in agreement with the maximum contaminant levels. In order to comply with NNEPA water quality standard water samples were subjected to electrochemical treatment. This method was selected due to its high removal efficiency for heavy metals and uranium, lower settlement time, production of smaller volume of waste mud and higher stability of waste mud compared to physico-chemical treatment. Following the treatment, concentrations of heavy metals and activities of radionuclides in all samples were significantly lower compared to NNEPA or WHO regulated values. The maximum removal efficiencies for color, turbidity, arsenic, manganese, molybdenum and

Devices, materials, and processes for nano-electronics: characterization with advanced X-ray techniques using lab-based and synchrotron radiation sources

International Nuclear Information System (INIS)

Zschech, E.; Wyon, C.; Murray, C.E.; Schneider, G.

2011-01-01

Future nano-electronics manufacturing at extraordinary length scales, new device structures, and advanced materials will provide challenges to process development and engineering but also to process control and physical failure analysis. Advanced X-ray techniques, using lab systems and synchrotron radiation sources, will play a key role for the characterization of thin films, nano-structures, surfaces, and interfaces. The development of advanced X-ray techniques and tools will reduce risk and time for the introduction of new technologies. Eventually, time-to-market for new products will be reduced by the timely implementation of the best techniques for process development and process control. The development and use of advanced methods at synchrotron radiation sources will be increasingly important, particularly for research and development in the field of advanced processes and new materials but also for the development of new X-ray components and procedures. The application of advanced X-ray techniques, in-line, in out-of-fab analytical labs and at synchrotron radiation sources, for research, development, and manufacturing in the nano-electronics industry is reviewed. The focus of this paper is on the study of nano-scale device and on-chip interconnect materials, and materials for 3D IC integration as well. (authors)

Design parameters and source terms: Volume 3, Source terms: Revision 0

International Nuclear Information System (INIS)

1987-09-01

The Design Parameters and Source Terms Document was prepared in accordance with DOE request and to provide data for the environmental impact study to be performed in the future for the Deaf Smith County, Texas site for a nuclear waste repository in salt. This document updates a previous unpublished report to the level of the Site Characterization Plan /endash/ Conceptual Design Report, SCP-CDR. The previous unpublished SCC Study identifies the data needs for the Environmental Assessment effort for seven possible salt repository sites

Laser and beta source setup characterization of 3D-DDTC detectors fabricated at FBK-irst

Energy Technology Data Exchange (ETDEWEB)

Zoboli, A. [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38050 Povo (Trento) (Italy)], E-mail: zoboli@disi.unitn.it; Dalla Betta, G.-F. [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38050 Povo (Trento) (Italy); Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38050 Povo (Trento) (Italy); Bosisio, L. [Dip. di Fisica e INFN, Universita di Trieste, I-34127, Trieste (Italy); Eckert, S.; Kuehn, S.; Parzefall, U. [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Piemonte, C.; Ronchin, S.; Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38050 Povo (Trento) (Italy)

2009-06-01

We report on the functional characterization of the first batch of 3D Double-Sided Double Type Column (3D-DDTC) detectors fabricated at FBK, Trento. This detector concept represents the evolution of the previous 3D-STC detectors towards full 3D detectors, and is expected to achieve a performance which is comparable to standard 3D detectors, but with a simpler fabrication process. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary readout. This paper reports spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a Beta source.

Laser and beta source setup characterization of 3D-DDTC detectors fabricated at FBK-irst

International Nuclear Information System (INIS)

Zoboli, A.; Dalla Betta, G.-F.; Boscardin, M.; Bosisio, L.; Eckert, S.; Kuehn, S.; Parzefall, U.; Piemonte, C.; Ronchin, S.; Zorzi, N.

2009-01-01

We report on the functional characterization of the first batch of 3D Double-Sided Double Type Column (3D-DDTC) detectors fabricated at FBK, Trento. This detector concept represents the evolution of the previous 3D-STC detectors towards full 3D detectors, and is expected to achieve a performance which is comparable to standard 3D detectors, but with a simpler fabrication process. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary readout. This paper reports spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a Beta source.

Characterizing and sourcing ambient PM2.5 over key emission regions in China II: Organic molecular markers and CMB modeling

Science.gov (United States)

Zhou, Jiabin; Xiong, Ying; Xing, Zhenyu; Deng, Junjun; Du, Ke

2017-08-01

From November 2012 to July 2013, a sampling campaign was completed for comprehensive characterization of PM2.5 over four key emission regions in China: Beijing-Tianjin-Hebei (BTH), Yangzi River Delta (YRD), Pearl River Delta (PRD), and Sichuan Basin (SB). A multi-method approach, adopting different analytical and receptor modeling methods, was employed to determine the relative abundances of region-specific air pollution constituents and contributions of emission sources. This paper is focused on organic molecular marker based source apportionment using chemical mass balance (CMB) receptor modeling. Analyses of the organic molecular markers revealed that vehicle emission, coal combustion, biomass burning, meat cooking and natural gas combustion were the major contributors to organic carbon (OC) in PM2.5. The vehicle emission dominated the sources contributing to OC in spring at four sampling sites. During wintertime, the coal combustion had highest contribution to OC at BTH site, while the major source contributing to OC at YRD and PRD sites was vehicle emission. In addition, the relative contributions of different emission sources to PM2.5 mass at a specific location site and in a specific season revealed seasonal and spatial variations across all four sampling locations. The largest contributor to PM2.5 mass was secondary sulfate (14-17%) in winter at the four sites. The vehicle emission was found to be the major source (14-21%) for PM2.5 mass at PRD site. The secondary ammonium has minor variation (4-5%) across the sites, confirming the influences of regional emission sources on these sites. The distinct patterns of seasonal and spatial variations of source apportionment observed in this study were consistent with the findings in our previous paper based upon water-soluble ions and carbonaceous fractions. This makes it essential for the local government to make season- and region-specific mitigation strategies for abating PM2.5 pollution in China.

Feasibility study for the spallation neutron source (SNQ). Pt. 1

International Nuclear Information System (INIS)

Bauer, G.S.; Sebening, H.; Vetter, J.E.; Willax, H.

1981-06-01

A concept for a new neutron source for fundamental research has been developed and is described in this report. The spallation neutron source SNQ is characterized in its first stage by a time average thermal neutron flux of 7 x 10 14 cm -2 s -1 and a peak flux of 1.3 x 10 16 cm -2 s -1 at 100 Hz repetition rate. The scientific case is presented with particular emphasis on solid state and nuclear physics. In these research domains, unique conditions are given for experimental use. The proposed machine consists in its basic stage of a 1.1 GeV, 5 mA time average, 100 mA peak current proton linear accelerator, a rotating lead target, and H 2 O and D 2 O moderators. Additional beam channels are provided for experiments with protons at 350 MeV and at the final energy. Construction of the SNQ is considered feasible within eight years at a cost of 680 million DM. As future options, use of uranium as a target material, increase of the accelerator beam power by a factor of 2, addition of a pulse compressor and a second target station for pulsed neutron and neutrino research are described. As a back-up solution to the rotating target, a liquid metal target was studied. (orig.) [de

Characterization of the relationship between ceramic pot filter water production and turbidity in source water.

Science.gov (United States)

Salvinelli, Carlo; Elmore, A Curt; Reidmeyer, Mary R; Drake, K David; Ahmad, Khaldoun I

2016-11-01

Ceramic pot filters represent a common and effective household water treatment technology in developing countries, but factors impacting water production rate are not well-known. Turbidity of source water may be principal indicator in characterizing the filter's lifetime in terms of water production capacity. A flow rate study was conducted by creating four controlled scenarios with different turbidities, and influent and effluent water samples were tested for total suspended solids and particle size distribution. A relationship between average flow rate and turbidity was identified with a negative linear trend of 50 mLh -1 /NTU. Also, a positive linear relationship was found between the initial flow rate of the filters and average flow rate calculated over the 23 day life of the experiment. Therefore, it was possible to establish a method to estimate the average flow rate given the initial flow rate and the turbidity in the influent water source, and to back calculate the maximum average turbidity that would need to be maintained in order to achieve a specific average flow rate. However, long-term investigations should be conducted to assess how these relationships change over the expected CPF lifetime. CPFs rejected fine suspended particles (below 75 μm), especially particles with diameters between 0.375 μm and 10 μm. The results confirmed that ceramic pot filters are able to effectively reduce turbidity, but pretreatment of influent water should be performed to avoid premature failure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Preparation And Characterization Of Modified Calcium Oxide From Natural Sources And Their Application In The Transesterification Of Palm Oil

Directory of Open Access Journals (Sweden)

Aqliliriana

2015-08-01

Full Text Available Abstract Calcium oxide catalysts were prepared from natural calcium sources such as limestone and mud creeper shell and the catalytic activities were evaluated in the transesterification of palm oil. The raw material which mainly composed of calcium carbonate can be easily converted to calcium oxide CaO after calcination above 1000 K for few hours. Abundant cheap sources benign high conversion and nontoxic become main advantages of these catalysts. The catalysts were characterized by XRF TGA XRD CO2-TPD SEM and BET methods. Thermal decomposition of CaCO3 will produced CaO which later will be converted into calcium hydroxide CaOH2 via simple hydration technique. Under optimum reaction condition methanol to oil ratio 151 catalyst loading 3 wt. reaction temperature 338 K for 5 hours the highest conversion of palm oil to methyl ester recorded were 98 and 94 when using modified limestone and mud creeper shell respectively. The results observed an increment up to 80 by using modified catalysts with characterization results showed high in basicity and surface area. Hence promising materials via simple and cheap method can be achieved.

Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

DEFF Research Database (Denmark)

Bravo Gonzalo, Ivan; Engelsholm, Rasmus Dybbro; Bang, Ole

2017-01-01

bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which...... the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation...... (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise...

Inverse source problems for eddy current equations

International Nuclear Information System (INIS)

Rodríguez, Ana Alonso; Valli, Alberto; Camaño, Jessika

2012-01-01

We study the inverse source problem for the eddy current approximation of Maxwell equations. As for the full system of Maxwell equations, we show that a volume current source cannot be uniquely identified by knowledge of the tangential components of the electromagnetic fields on the boundary, and we characterize the space of non-radiating sources. On the other hand, we prove that the inverse source problem has a unique solution if the source is supported on the boundary of a subdomain or if it is the sum of a finite number of dipoles. We address the applicability of this result for the localization of brain activity from electroencephalography and magnetoencephalography measurements. (paper)

Arctic Aerosols and Sources

DEFF Research Database (Denmark)

Nielsen, Ingeborg Elbæk

2017-01-01

Since the Industrial Revolution, the anthropogenic emission of greenhouse gases has been increasing, leading to a rise in the global temperature. Particularly in the Arctic, climate change is having serious impact where the average temperature has increased almost twice as much as the global during......, ammonium, black carbon, and trace metals. This PhD dissertation studies Arctic aerosols and their sources, with special focus on black carbon, attempting to increase the knowledge about aerosols’ effect on the climate in an Arctic content. The first part of the dissertation examines the diversity...... of aerosol emissions from an important anthropogenic aerosol source: residential wood combustion. The second part, characterizes the chemical and physical composition of aerosols while investigating sources of aerosols in the Arctic. The main instrument used in this research has been the state...

Seismic rupture study using near-source data: application to seismic hazard assessment

International Nuclear Information System (INIS)

Hernandez, Bruno

2000-01-01

This work presents seismic source studies using near-field data. In accordance with the quality and the quantity of available data we developed and applied various methods to characterize the seismic source. Macro-seismic data are used to verify if simple and robust methods used on recent instrumental earthquakes may provide a good tool to calibrate historical events in France. These data are often used to characterize earthquakes to be taken into account for seismic hazard assessment in moderate seismicity regions. Geodetic data (SAR, GPS) are used to estimate the slip distribution on the fault during the 1992, Landers, California earthquake. These data are also used to precise the location and the geometry of the main events of the 1997, Colfiorito, central Italy, earthquake sequence. Finally, the strong motions contain the most complete information about rupture process. These data are used to discriminate between two possible fault planes of the 1999, north India, Chamoli earthquake. The strong motions recorded close to the 1999, Mexico, Oaxaca earthquake are used to constrain the rupture history. Strong motions a.re also used in combination with geodetic data to access the rupture history of the Landers earthquake and the main events of the Colfiorito seismic sequence. For the Landers earthquake, the data quality and complementarity offered the possibility to describe the rupture development with accuracy. The large heterogeneities in both slip amplitude and rupture velocity variations suggest that the rupture propagates by breaking successive asperities rather than by propagating like a pulse at constant velocity. The rupture front slows as it encounters barriers and accelerates within main asperities. (author)

Characterization of atomic oxygen from an ECR plasma source

International Nuclear Information System (INIS)

Naddaf, M; Bhoraskar, V N; Mandale, A B; Sainkar, S R; Bhoraskar, S V

2002-01-01

A low-power microwave-assisted electron cyclotron resonance (ECR) plasma system is shown to be a powerful and effective source of atomic oxygen (AO) useful in material processing. A 2.45 GHz microwave source with maximum power of 600 W was launched into the cavity to generate the ECR plasma. A catalytic nickel probe was used to determine the density of AO. The density of AO is studied as a function of pressure and axial position of the probe in the plasma chamber. It was found to vary from ∼1x10 20 to ∼10x10 20 atom m -3 as the plasma pressure was varied from 0.8 to 10 mTorr. The effect of AO in oxidation of silver is investigated by gravimetric analysis. The stoichiometric properties of the oxide are studied using the x-ray photoelectron spectroscopy as well as energy dispersive x-ray analysis. The degradation of the silver surface due to sputtering effect was viewed by scanning electron spectroscopy. The sputtering yield of oxygen ions in the plasma is calculated using the TRIM code. The effects of plasma pressure and the distance from the ECR zone on the AO density were also investigated. The density of AO measured by oxidation of silver is in good agreement with results obtained from the catalytic nickel probe

Characterization of atomic oxygen from an ECR plasma source

Science.gov (United States)

Naddaf, M.; Bhoraskar, V. N.; Mandale, A. B.; Sainkar, S. R.; Bhoraskar, S. V.

2002-11-01

A low-power microwave-assisted electron cyclotron resonance (ECR) plasma system is shown to be a powerful and effective source of atomic oxygen (AO) useful in material processing. A 2.45 GHz microwave source with maximum power of 600 W was launched into the cavity to generate the ECR plasma. A catalytic nickel probe was used to determine the density of AO. The density of AO is studied as a function of pressure and axial position of the probe in the plasma chamber. It was found to vary from ~1×1020 to ~10×1020 atom m-3 as the plasma pressure was varied from 0.8 to 10 mTorr. The effect of AO in oxidation of silver is investigated by gravimetric analysis. The stoichiometric properties of the oxide are studied using the x-ray photoelectron spectroscopy as well as energy dispersive x-ray analysis. The degradation of the silver surface due to sputtering effect was viewed by scanning electron spectroscopy. The sputtering yield of oxygen ions in the plasma is calculated using the TRIM code. The effects of plasma pressure and the distance from the ECR zone on the AO density were also investigated. The density of AO measured by oxidation of silver is in good agreement with results obtained from the catalytic nickel probe.

Characterization of atomic oxygen from an ECR plasma source

Energy Technology Data Exchange (ETDEWEB)

Naddaf, M [Center for Advanced Studies in Material Science and Solid State Physics, University of Pune, Pune 411 007 (India); Bhoraskar, V N [Center for Advanced Studies in Material Science and Solid State Physics, University of Pune, Pune 411 007 (India); Mandale, A B [National Chemical Laboratory, Pashan, Pune 411008 (India); Sainkar, S R [National Chemical Laboratory, Pashan, Pune 411008 (India); Bhoraskar, S V [Center for Advanced Studies in Material Science and Solid State Physics, University of Pune, Pune 411 007 (India)

2002-11-01

A low-power microwave-assisted electron cyclotron resonance (ECR) plasma system is shown to be a powerful and effective source of atomic oxygen (AO) useful in material processing. A 2.45 GHz microwave source with maximum power of 600 W was launched into the cavity to generate the ECR plasma. A catalytic nickel probe was used to determine the density of AO. The density of AO is studied as a function of pressure and axial position of the probe in the plasma chamber. It was found to vary from {approx}1x10{sup 20} to {approx}10x10{sup 20} atom m{sup -3} as the plasma pressure was varied from 0.8 to 10 mTorr. The effect of AO in oxidation of silver is investigated by gravimetric analysis. The stoichiometric properties of the oxide are studied using the x-ray photoelectron spectroscopy as well as energy dispersive x-ray analysis. The degradation of the silver surface due to sputtering effect was viewed by scanning electron spectroscopy. The sputtering yield of oxygen ions in the plasma is calculated using the TRIM code. The effects of plasma pressure and the distance from the ECR zone on the AO density were also investigated. The density of AO measured by oxidation of silver is in good agreement with results obtained from the catalytic nickel probe.

Chemical characterization of atmospheric particles and source apportionment in the vicinity of a steelmaking industry

International Nuclear Information System (INIS)

Almeida, S.M.; Lage, J.; Fernández, B.; Garcia, S.; Reis, M.A.; Chaves, P.C.

2015-01-01

The objective of this work was to provide a chemical characterization of atmospheric particles collected in the vicinity of a steelmaking industry and to identify the sources that affect PM 10 levels. A total of 94 PM samples were collected in two sampling campaigns that occurred in February and June/July of 2011. PM 2.5 and PM 2.5–10 were analyzed for a total of 22 elements by Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission. The concentrations of water soluble ions in PM 10 were measured by Ion Chromatography and Indophenol-Blue Spectrophotometry. Positive Matrix Factorization receptor model was used to identify sources of particulate matter and to determine their mass contribution to PM 10 . Seven main groups of sources were identified: marine aerosol identified by Na and Cl (22%), steelmaking and sinter plant represented by As, Cr, Cu, Fe, Ni, Mn, Pb, Sb and Zn (11%), sinter plant stack identified by NH 4 + , K and Pb (12%), an unidentified Br source (1.8%), secondary aerosol from coke making and blast furnace (19%), fugitive emissions from the handling of raw material, sinter plant and vehicles dust resuspension identified by Al, Ca, La, Si, Ti and V (14%) and sinter plant and blast furnace associated essentially with Fe and Mn (21%). - Highlights: • Emissions from steelworks are very complex. • The larger steelworks contribution to PM 10 was from blast furnace and sinter plant. • Sinter plant stack emissions contributed for 12% of the PM 10 mass. • Secondary aerosol from coke making and blast furnace contributed for 19% of the PM 10 . • Fugitive dust emissions highly contribute to PM 10 mass

Hydrogeologic characterization of basalts: The northern rim of the Columbia Plateau Physiographic Province and of the Creston Study Area, eastern Washington

International Nuclear Information System (INIS)

Steele, T.D.; Paschis, J.A.; Koenig, R.A.

1988-03-01

This report provides a general but comprehensive characterization of hydrogeologic and hydrogeochemical baseline conditions for the Creston area located along the northern rim of the Columbia Plateau physiographic province. Historical as well as recent data and other available information from previous studies and alternative sources have been considered in this baseline hydrological characterization. These include data and information on water levels, aquifer characteristics, and water quality for shallow basalt units comprising the Wanapum Formation and the Grande Ronde Formation in the Creston study area and for the general region surrounding this study area. The overall goal of this hydrologic characterization was to provide useful information leading to the selection of the Roza Member of the Wanapum Formation as the study's basalt horizon and for other related, subsequent study components of In-Situ's research project. 110 refs., 52 figs., 25 tabs

Overview of waste isoltaion safety assessment program and description of source term characterization task at PNL

International Nuclear Information System (INIS)

Bradley, D.

1977-01-01

A project is being conducted to develop and illustrate the methods and obtain the data necessary to assess the safety of long-term disposal of high-level radioactive waste in geologic formations. The methods and data will initially focus on generic geologic isolation systems but will ultimately be applied to the long-term safety assessment of specific candidate sites that are selected in the NWTS Program. The activities of waste isolation safety assessment (WISAP) are divided into six tasks: (1) Safety Assessment Concepts and Methods, (2) Disruptive Event Analysis, (3) Source Characterization, (4) Transport Modeling, (5) Transport Data and (6) Societal Acceptance

A Detailed Study of Debris Flow Source Areas in the Northern Colorado Front Range.

Science.gov (United States)

Arana-Morales, A.; Baum, R. L.; Godt, J.

2014-12-01

Nearly continuous, heavy rainfall occurred during 9-13 September 2013 causing flooding and widespread landslides and debris flows in the northern Colorado Front Range. Whereas many recent studies have identified erosion as the most common process leading to debris flows in the mountains of Colorado, nearly all of the debris flows mapped in this event began as small, shallow landslides. We mapped the boundaries of 415 September 2013 debris flows in the Eldorado Springs and Boulder 7.5-minute quadrangles using 0.5-m-resolution satellite imagery. We characterized the landslide source areas of six debris flows in the field as part of an effort to identify what factors controlled their locations. Four were on a dip slope in sedimentary rocks in the Pinebrook Hills area, near Boulder, and the other two were in granitic rocks near Gross Reservoir. Although we observed no obvious geomorphic differences between the source areas and surrounding non-landslide areas, we noted several characteristics that the source areas all had in common. Slopes of the source areas ranged from 28° to 35° and most occurred on planar or slightly concave slopes that were vegetated with grass, small shrubs, and sparse trees. The source areas were shallow, irregularly shaped, and elongated downslope: widths ranged from 4 to 9 m, lengths from 6 to 40 m and depths ranged from 0.7 to 1.2 m. Colluvium was the source material for all of the debris flows and bedrock was exposed in the basal surface of all of the source areas. We observed no evidence for concentrated surface runoff upslope from the sources. Local curvature and roughness of bedrock and surface topography, and depth distribution and heterogeneity of the colluvium appear to have controlled the specific locations of these shallow debris-flow source areas. The observed distribution and characteristics of the source areas help guide ongoing efforts to model initiation of the debris flows.

Characterization of Dust Properties at the Source Region During ACE-Asia

Science.gov (United States)

Tsay, Si-Chee; Lau, William (Technical Monitor)

2001-01-01

ACE (Aerosol Characterization Experiment)-Asia is designed to study the compelling variability in spatial and temporal scale of both pollution-derived and naturally-occurring aerosols, which often exist in high concentrations over eastern Asia and along the rim of the western Pacific. The phase-I of ACE-Asia was conducted from March-May 2001 in the vicinity of the Gobi desert, east coast of China, Yellow Sea, Korea, and Japan, along the pathway of Kosa (severe events that blanket East Asia with yellow desert dust, peaked in the Spring season). Asian dust typically originates in desert areas far from polluted urban regions. During transport, dust layers can interact with anthropogenic sulfate and soot aerosols from heavily polluted urban areas. Added to the complex effects of clouds and natural marine aerosols, dust particles reaching the marine environment can have drastically different properties than those from the source. Thus, understanding the unique temporal and spatial variations of Asian dust is of special importance in regional-to-global climate issues such as radiative forcing, the hydrological cycle, and primary biological productivity in the mid-Pacific Ocean. During ACE-Asia we have measured continuously aerosol optical/radiative properties, column precipitable water amount, and surface reflectivity over homogeneous areas from surface. The inclusion of flux measurements permits the determination of dust aerosol radiative flux in addition to measurements of loading and optical thickness. At the time of the Terra/MODIS overpass, these ground-based observations can provide valuable data to compare with MODIS retrievals over land. Preliminary results will be presented and discussed their implications in regional climatic effects.

Development and characterization of a tunable ultrafast X-ray source via inverse-Compton-scattering

International Nuclear Information System (INIS)

Jochmann, Axel

2014-01-01

Ultrashort, nearly monochromatic hard X-ray pulses enrich the understanding of the dynamics and function of matter, e.g., the motion of atomic structures associated with ultrafast phase transitions, structural dynamics and (bio)chemical reactions. Inverse Compton backscattering of intense laser pulses from relativistic electrons not only allows for the generation of bright X-ray pulses which can be used in a pump-probe experiment, but also for the investigation of the electron beam dynamics at the interaction point. The focus of this PhD work lies on the detailed understanding of the kinematics during the interaction of the relativistic electron bunch and the laser pulse in order to quantify the influence of various experiment parameters on the emitted X-ray radiation. The experiment was conducted at the ELBE center for high power radiation sources using the ELBE superconducting linear accelerator and the DRACO Ti:sapphire laser system. The combination of both these state-of-the-art apparatuses guaranteed the control and stability of the interacting beam parameters throughout the measurement. The emitted X-ray spectra were detected with a pixelated detector of 1024 by 256 elements (each 26μm by 26μm) to achieve an unprecedented spatial and energy resolution for a full characterization of the emitted spectrum to reveal parameter influences and correlations of both interacting beams. In this work the influence of the electron beam energy, electron beam emittance, the laser bandwidth and the energy-anglecorrelation on the spectra of the backscattered X-rays is quantified. A rigorous statistical analysis comparing experimental data to ab-initio 3D simulations enabled, e.g., the extraction of the angular distribution of electrons with 1.5% accuracy and, in total, provides predictive capability for the future high brightness hard X-ray source PHOENIX (Photon electron collider for Narrow bandwidth Intense X-rays) and potential all optical gamma-ray sources. The results

Study of non-metallic inclusion sources in steel

International Nuclear Information System (INIS)

Khons, Ya.; Mrazek, L.

1976-01-01

A study of potential inclusion sources was carried out at the Tvinec steel plant using an unified labelling procedure for different sources. A lanthanum oxide labelling method has been used for refractories with the subsequent La determination in steel by the neutron activation analysis. Samarium and cerium oxides and the 141 Ce radionuclide have been used in conjunction with the testing. The following sources of exogenous inclusions have been studied: 1)Refractory material comprising fireclay and corundum for steel-teeming trough in open-heart furnaces; 2) Fireclay bottom-pouring refractories; 3) Steel-teeming laddle lining; 4) Heat-insulating and exothermic compounds for steel ingots; 5) Vacuum treatment plant lining; 6) Open-hearth and electric arc furnace slag. The major oxide inclusion source in steel was found to be represented by the furnace slag, since it forms about 40 p.c. of all oxide inclusions. The contributions of the remaining sources did not exceede 5 p.c. each

On using peak amplitude and rise time for AE source characterization

Indian Academy of Sciences (India)

R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

The major objective of signal analysis is to study the characteristics of the sources of emissions. ... When AE is used as a non-destructive evaluation tool, this information is extracted using a .... Hence, frequency response H (f ) of the transducer.

Detection and characterization of lightning-based sources using continuous wavelet transform: application to audio-magnetotellurics

Science.gov (United States)

Larnier, H.; Sailhac, P.; Chambodut, A.

2018-01-01

Atmospheric electromagnetic waves created by global lightning activity contain information about electrical processes of the inner and the outer Earth. Large signal-to-noise ratio events are particularly interesting because they convey information about electromagnetic properties along their path. We introduce a new methodology to automatically detect and characterize lightning-based waves using a time-frequency decomposition obtained through the application of continuous wavelet transform. We focus specifically on three types of sources, namely, atmospherics, slow tails and whistlers, that cover the frequency range 10 Hz to 10 kHz. Each wave has distinguishable characteristics in the time-frequency domain due to source shape and dispersion processes. Our methodology allows automatic detection of each type of event in the time-frequency decomposition thanks to their specific signature. Horizontal polarization attributes are also recovered in the time-frequency domain. This procedure is first applied to synthetic extremely low frequency time-series with different signal-to-noise ratios to test for robustness. We then apply it on real data: three stations of audio-magnetotelluric data acquired in Guadeloupe, oversea French territories. Most of analysed atmospherics and slow tails display linear polarization, whereas analysed whistlers are elliptically polarized. The diversity of lightning activity is finally analysed in an audio-magnetotelluric data processing framework, as used in subsurface prospecting, through estimation of the impedance response functions. We show that audio-magnetotelluric processing results depend mainly on the frequency content of electromagnetic waves observed in processed time-series, with an emphasis on the difference between morning and afternoon acquisition. Our new methodology based on the time-frequency signature of lightning-induced electromagnetic waves allows automatic detection and characterization of events in audio

Variability patterns of Rossby wave source

Energy Technology Data Exchange (ETDEWEB)

Shimizu, Marilia Harumi; Albuquerque Cavalcanti, Iracema Fonseca de [National Institute for Space Research (INPE), Center for Weather Forecasting and Climate Studies (CPTEC), Sao Jose dos Campos (Brazil)

2011-08-15

Rossby waves (RW) propagation due to a local forcing is one of the mechanisms responsible for wave trains configurations known as teleconnections. The term teleconnection refers to anomalies patterns that are correlated in several regions of the world, causing large-scale changes in atmospheric waves patterns and temperature and precipitation regimes. The aim of teleconnections studies is to provide a better understanding of atmospheric variability and their mechanisms of action in order to identify patterns that can be tracked and predicted. The purpose of this study was to characterize seasonal and spatial variability of atmospheric RW sources. The RW source at 200 hPa was calculated for the four seasons with reanalysis data of zonal and meridional wind. In the Northern Hemisphere (NH), the RW sources were located on East Asia, North America, North Atlantic and Pacific. The main RW sources in the Southern Hemisphere (SH) were located over Intertropical, South Pacific, South Atlantic and South Indian Convergence Zones. Extratropical regions were also identified, mainly to the south of Australia. The vortex stretching term (S1) and the advection of absolute vorticity by the divergent wind (S2) were analyzed to discuss the physical mechanisms for RW generation. In the NH, the source at East Asia in DJF changed to a sink in JJA, related to the dominance of S1 term in DJF and S2 term in JJA. In the SH, the vortex stretching term had the dominant contribution for RW source located to the south of Australia. The main forcing for RW sources at east of Australia was the advection of absolute vorticity by divergent flow. Over South America, both terms contributed to the source in DJF. The main modes of RW source variability were discussed by using empirical orthogonal functions analysis. RW variability was characterized by wave trains configurations in both hemispheres over regions of jet streams and storm tracks, associated with favorable and unfavorable areas for RW

Development of methodology for the characterization of radioactive sealed sources

International Nuclear Information System (INIS)

Ferreira, Robson de Jesus

2010-01-01

Sealed radioactive sources are widely used in many applications of nuclear technology in industry, medicine, research and others. The International Atomic Energy Agency (IAEA) estimates tens of millions sources in the world. In Brazil, the number is about 500 thousand sources, if the Americium-241 sources present in radioactive lightning rods and smoke detectors are included in the inventory. At the end of the useful life, most sources become disused, constitute a radioactive waste, and are then termed spent sealed radioactive sources (SSRS). In Brazil, this waste is collected by the research institutes of the Nuclear Commission of Nuclear Energy and kept under centralized storage, awaiting definition of the final disposal route. The Waste Management Laboratory (WML) at the Nuclear and Energy Research Institute is the main storage center, having received until July 2010 about 14.000 disused sources, not including the tens of thousands of lightning rod and smoke detector sources. A program is underway in the WML to replacing the original shielding by a standard disposal package and to determining the radioisotope content and activity of each one. The identification of the radionuclides and the measurement of activities will be carried out with a well type ionization chamber. This work aims to develop a methodology for measuring or to determine the activity SSRS stored in the WML accordance with its geometry and determine their uncertainties. (author)

Neutronic studies on decoupled hydrogen moderator for a short-pulse spallation source

International Nuclear Information System (INIS)

Harada, Masahide; Watanabe, Noboru; Teshigawara, Makoto; Kai, Tetsuya; Ikeda, Yujiro

2005-01-01

Neutronic studies of decoupled hydrogen moderators were performed by calculations taking into account para hydrogen content, decoupling energy, moderator dimensions/shapes and reflector material. Low-energy parts of calculated spectral intensities with different para hydrogen contents were analyzed by a modified Maxwell function to characterize neutron spectra. The result shows that a 100% para hydrogen moderator gives the highest pulse peak intensity together with the narrowest pulse width and the shortest decay times. Pulse broadening with a reflector was explained by time distributions of source neutrons entering into the moderator through a decoupler. Material dependence of time distribution was studied. A decoupling energy higher than 1 eV does not bring about a large improvement in pulse widths and decay times, even at a large penalty in the peak intensity. The optimal moderator thickness was also discussed for a rectangular parallelepipe-shaped and a canteen-shaped moderator

Uncertainty Quantification in Earthquake Source Characterization with Probabilistic Centroid Moment Tensor Inversion

Science.gov (United States)

Dettmer, J.; Benavente, R. F.; Cummins, P. R.

2017-12-01

This work considers probabilistic, non-linear centroid moment tensor inversion of data from earthquakes at teleseismic distances. The moment tensor is treated as deviatoric and centroid location is parametrized with fully unknown latitude, longitude, depth and time delay. The inverse problem is treated as fully non-linear in a Bayesian framework and the posterior density is estimated with interacting Markov chain Monte Carlo methods which are implemented in parallel and allow for chain interaction. The source mechanism and location, including uncertainties, are fully described by the posterior probability density and complex trade-offs between various metrics are studied. These include the percent of double couple component as well as fault orientation and the probabilistic results are compared to results from earthquake catalogs. Additional focus is on the analysis of complex events which are commonly not well described by a single point source. These events are studied by jointly inverting for multiple centroid moment tensor solutions. The optimal number of sources is estimated by the Bayesian information criterion to ensure parsimonious solutions. [Supported by NSERC.

Medicina array demonstrator: calibration and radiation pattern characterization using a UAV-mounted radio-frequency source

Science.gov (United States)

Pupillo, G.; Naldi, G.; Bianchi, G.; Mattana, A.; Monari, J.; Perini, F.; Poloni, M.; Schiaffino, M.; Bolli, P.; Lingua, A.; Aicardi, I.; Bendea, H.; Maschio, P.; Piras, M.; Virone, G.; Paonessa, F.; Farooqui, Z.; Tibaldi, A.; Addamo, G.; Peverini, O. A.; Tascone, R.; Wijnholds, S. J.

2015-06-01

One of the most challenging aspects of the new-generation Low-Frequency Aperture Array (LFAA) radio telescopes is instrument calibration. The operational LOw-Frequency ARray (LOFAR) instrument and the future LFAA element of the Square Kilometre Array (SKA) require advanced calibration techniques to reach the expected outstanding performance. In this framework, a small array, called Medicina Array Demonstrator (MAD), has been designed and installed in Italy to provide a test bench for antenna characterization and calibration techniques based on a flying artificial test source. A radio-frequency tone is transmitted through a dipole antenna mounted on a micro Unmanned Aerial Vehicle (UAV) (hexacopter) and received by each element of the array. A modern digital FPGA-based back-end is responsible for both data-acquisition and data-reduction. A simple amplitude and phase equalization algorithm is exploited for array calibration owing to the high stability and accuracy of the developed artificial test source. Both the measured embedded element patterns and calibrated array patterns are found to be in good agreement with the simulated data. The successful measurement campaign has demonstrated that a UAV-mounted test source provides a means to accurately validate and calibrate the full-polarized response of an antenna/array in operating conditions, including consequently effects like mutual coupling between the array elements and contribution of the environment to the antenna patterns. A similar system can therefore find a future application in the SKA-LFAA context.

A Toxicology and Characterization Study of Microplastics

Science.gov (United States)

Parker, Amy; Sullivan, Kelley; n/a Collaboration

Plastic is everywhere. Microplastic particles are found in our toothpaste and soap, and are also created when larger plastics degrade under natural forces and sunlight. Studies have shown that filter feeders in aquatic systems eat microplastics, which transports plastic up the food chain. We used fluorescence microscopy to characterize the size, shape, and types of plastic found in several personal care products in order to create a clear picture of a significant source of microplastics found in our local Cayuga Lake ecosystem in Upstate New York. We also studied toxin absorption and emission of these plastics using environmentally relevant concentrations of BPA. For Neutrogena face scrub, the microplastics were polyethylene and roughly pill shaped. The majority of these microplastics are either smaller than 0.1 mm2, or were distributed in a bell-shaped curve about 0.5 mm2. The concentration of a solution of environmentally relevant BPA that microplastics were immersed in decreased by 13% over a 12-hour period. These results indicate that these microplastics pose a threat to organisms in the environment - they are small enough and shaped appropriately to be mistaken as prey, and they absorb toxins quickly. As the number of microplastics exponentially build up in the environment, the food chain will be negatively affected. Ithaca College DANA Student Internship program.

Internal noise sources limiting contrast sensitivity.

Science.gov (United States)

Silvestre, Daphné; Arleo, Angelo; Allard, Rémy

2018-02-07

Contrast sensitivity varies substantially as a function of spatial frequency and luminance intensity. The variation as a function of luminance intensity is well known and characterized by three laws that can be attributed to the impact of three internal noise sources: early spontaneous neural activity limiting contrast sensitivity at low luminance intensities (i.e. early noise responsible for the linear law), probabilistic photon absorption at intermediate luminance intensities (i.e. photon noise responsible for de Vries-Rose law) and late spontaneous neural activity at high luminance intensities (i.e. late noise responsible for Weber's law). The aim of this study was to characterize how the impact of these three internal noise sources vary with spatial frequency and determine which one is limiting contrast sensitivity as a function of luminance intensity and spatial frequency. To estimate the impact of the different internal noise sources, the current study used an external noise paradigm to factorize contrast sensitivity into equivalent input noise and calculation efficiency over a wide range of luminance intensities and spatial frequencies. The impact of early and late noise was found to drop linearly with spatial frequency, whereas the impact of photon noise rose with spatial frequency due to ocular factors.

PM10 source apportionment study in Pleasant Valley, Nevada

International Nuclear Information System (INIS)

Egami, R.T.; Chow, J.C.; Watson, J.G.; DeLong, T.

1990-01-01

A source apportionment study was conducted between March 18 and April 4, 1988, at Pleasant Valley, Nevada, to evaluate air pollutant concentrations to which community residents were exposed and the source contributions to those pollutants. Daily PM 10 samples were taken for chemical speciation of 40 trace elements, ions, and organic and elemental carbon. This paper reports that the objectives of this case study are: to determine the emissions source composition of the potential upwind source, a geothermal plant; to measure the ambient particulate concentration and its chemical characteristics in Pleasant Valley; and to estimate the contributions of different emissions sources to PM 10 . The study found that: particulate emissions from the geothermal cooling-tower plume consisted primarily of sulfate, ammonia, chloride, and trace elements; no significant quantities of toxic inorganic species were found in the ambient air; ambient PM 10 concentrations in Pleasant Valley were within Federal standards; and source contribution to PM 10 were approximately 60% geological material; 20% motor vehicle exhaust; and 10% cooling-tower plume

Monte Carlo study of radial energy deposition from primary and secondary particles for narrow and large proton beamlet source models

International Nuclear Information System (INIS)

Peeler, Christopher R; Titt, Uwe

2012-01-01

In spot-scanning intensity-modulated proton therapy, numerous unmodulated proton beam spots are delivered over a target volume to produce a prescribed dose distribution. To accurately model field size-dependent output factors for beam spots, the energy deposition at positions radial to the central axis of the beam must be characterized. In this study, we determined the difference in the central axis dose for spot-scanned fields that results from secondary particle doses by investigating energy deposition radial to the proton beam central axis resulting from primary protons and secondary particles for mathematical point source and distributed source models. The largest difference in the central axis dose from secondary particles resulting from the use of a mathematical point source and a distributed source model was approximately 0.43%. Thus, we conclude that the central axis dose for a spot-scanned field is effectively independent of the source model used to calculate the secondary particle dose. (paper)

Antioxidants: Characterization, natural sources, extraction and analysis.

Science.gov (United States)

Oroian, Mircea; Escriche, Isabel

2015-08-01

Recently many review papers regarding antioxidants from different sources and different extraction and quantification procedures have been published. However none of them has all the information regarding antioxidants (chemistry, sources, extraction and quantification). This article tries to take a different perspective on antioxidants for the new researcher involved in this field. Antioxidants from fruit, vegetables and beverages play an important role in human health, for example preventing cancer and cardiovascular diseases, and lowering the incidence of different diseases. In this paper the main classes of antioxidants are presented: vitamins, carotenoids and polyphenols. Recently, many analytical methodologies involving diverse instrumental techniques have been developed for the extraction, separation, identification and quantification of these compounds. Antioxidants have been quantified by different researchers using one or more of these methods: in vivo, in vitro, electrochemical, chemiluminescent, electron spin resonance, chromatography, capillary electrophoresis, nuclear magnetic resonance, near infrared spectroscopy and mass spectrometry methods. Copyright © 2015. Published by Elsevier Ltd.

Contribution to the theoretical study, modelling and implementation of a multi-source system belonging to a micro-grid: considerations on power quality

International Nuclear Information System (INIS)

Houssamo, Issam

2012-01-01

The objective of this thesis is to study, analyze and develop a multi-source system belonging to a DC micro-grid with consideration of some aspects of the power quality. Chapter I presents the interest of the smart grid to ensure better coordination between distributed generation and power consumption. Having in view the prediction, a purely experimental model of photovoltaic source is developed and presented in Chapter II. Furthermore, in order to extract the maximum power of the photovoltaic source, a classical algorithm is improved and the extracted energy is compared with three other methods. In Chapter III, the security system elements, the electrochemical storage and the public grid, are characterized. In the case of a storage shortage, the public grid is used to supply power to the load, but also trade back excess energy. Chapter IV presents the control of multi-source system and its experimental validation. The energy management strategy taken into account is based on switching between the elements which secure the multi-source system. For this, the priority is given to storage characterized by its state of charge. Thanks to this strategy, the technical feasibility of the multi-source system is experimentally validated. Chapter V gives some aspects related to the improvement of the power quality: for the public grid side, a resonant controller is proposed, for the DC bus side, the pulsating power is eliminated by injecting the opposite signal supplied by the electrochemical storage. (author) [fr

Chemical characterization of atmospheric particles and source apportionment in the vicinity of a steelmaking industry

Energy Technology Data Exchange (ETDEWEB)

Almeida, S.M., E-mail: smarta@ctn.ist.utl.pt [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 139.7 km, 2695-066 Bobadela LRS (Portugal); Lage, J. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 139.7 km, 2695-066 Bobadela LRS (Portugal); Fernández, B. [Global R& D, ArcelorMittal, Avilés (Spain); Garcia, S. [Instituto de Soldadura e Qualidade, Av. Prof. Dr. Cavaco Silva, 33, 2740-120 Porto Salvo (Portugal); Reis, M.A.; Chaves, P.C. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, Estrada Nacional 10, 139.7 km, 2695-066 Bobadela LRS (Portugal)

2015-07-15

The objective of this work was to provide a chemical characterization of atmospheric particles collected in the vicinity of a steelmaking industry and to identify the sources that affect PM{sub 10} levels. A total of 94 PM samples were collected in two sampling campaigns that occurred in February and June/July of 2011. PM{sub 2.5} and PM{sub 2.5–10} were analyzed for a total of 22 elements by Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission. The concentrations of water soluble ions in PM{sub 10} were measured by Ion Chromatography and Indophenol-Blue Spectrophotometry. Positive Matrix Factorization receptor model was used to identify sources of particulate matter and to determine their mass contribution to PM{sub 10}. Seven main groups of sources were identified: marine aerosol identified by Na and Cl (22%), steelmaking and sinter plant represented by As, Cr, Cu, Fe, Ni, Mn, Pb, Sb and Zn (11%), sinter plant stack identified by NH{sub 4}{sup +}, K and Pb (12%), an unidentified Br source (1.8%), secondary aerosol from coke making and blast furnace (19%), fugitive emissions from the handling of raw material, sinter plant and vehicles dust resuspension identified by Al, Ca, La, Si, Ti and V (14%) and sinter plant and blast furnace associated essentially with Fe and Mn (21%). - Highlights: • Emissions from steelworks are very complex. • The larger steelworks contribution to PM{sub 10} was from blast furnace and sinter plant. • Sinter plant stack emissions contributed for 12% of the PM{sub 10} mass. • Secondary aerosol from coke making and blast furnace contributed for 19% of the PM{sub 10}. • Fugitive dust emissions highly contribute to PM{sub 10} mass.

PM2.5 source apportionment with organic markers in the Southeastern Aerosol Research and Characterization (SEARCH) study.

Science.gov (United States)

Watson, John G; Chow, Judith C; Lowenthal, Douglas H; Antony Chen, L-W; Shaw, Stephanie; Edgerton, Eric S; Blanchard, Charles L

2015-09-01

Positive matrix factorization (PMF) and effective variance (EV) solutions to the chemical mass balance (CMB) were applied to PM(2.5) (particulate matter with an aerodynamic diameter thermal carbon fraction concentrations were supplemented with detailed nonpolar organic speciation by thermal desorption-gas chromatography/mass spectrometry (TD-GC/MS). Source contribution estimates were calculated for motor vehicle exhaust, biomass burning, cooking, coal-fired power plants, road dust, vegetative detritus, and secondary sulfates and nitrates for Atlanta. Similar sources were found for Birmingham, with the addition of an industrial source and the separation of biomass burning into open burning and residential wood combustion. EV-CMB results based on conventional species were qualitatively similar to those estimated by PMF-CMB. Secondary ammonium sulfate was the largest contributor, accounting for 27-38% of PM(2.5), followed by biomass burning (21-24%) and motor vehicle exhaust (9-24%) at both sites, with 4-6% of PM(2.5) attributed to coal-fired power plants by EV-CMB. Including organic compounds in the EV-CMB reduced the motor vehicle exhaust and biomass burning contributions at both sites, with a 13-23% deficit for PM(2.5) mass. The PMF-CMB solution showed mixing of sources within the derived factors, both with and without the addition of speciated organics, as is often the case with complex source mixtures such as those at these urban-scale sites. The nonpolar TD-GC/MS compounds can be obtained from existing filter samples and are a useful complement to the elements, ions, and carbon fractions. However, they should be supplemented with other methods, such as TD-GC/MS on derivitized samples, to obtain a wider range of polar compounds such as sterols, sugars, and organic acids. The PMF and EV solutions to the CMB equations are complementary to, rather than replacements for, each other, as comparisons of their results reveal uncertainties that are not otherwise evident

Characterization of tunable light source by optical parametric oscillator for high resolution spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Wu, J. W. [Ewha Womens Univ., Seoul (Korea); Rhee, B. G. [Sejong Univ., Seoul (Korea); Park, S. W. [Yonsei Univ., Seoul (Korea); Noh, J. W. [Inha Univ., Incheon (Korea)

1998-04-01

A tunable light source is developed by the optical parametric oscillator, which is very useful for a high resolution spectroscopy. The electronic structure of molecules and atoms can be examined by a proper coherent light source. Optical parametric oscillator provides light sources stable and widely tunable. In this work, the characteristics of the parametric optical generation are examined in the LiNbO{sub 3}. The theoretical analysis as well as the experimental measurement is performed. The pump laser is a second harmonic of Nd:YAG laser, and the parametric gain is measured. The characteristics of singly resonant oscillator and doubly resonant oscillator is studied as a function of temperature. It is found that 1mole% MgO:LiNbO{sub 3} crystal provides the tunability from 0.6{mu}m to 3.0{mu}m wavelength. Both the critical and noncritical phase matching are studied. The optical damage occurring in a congruent LiNbO{sub 3} crystal was not observed in 1mole% MgO:LiNbO{sub 3} crystal, opening a possibility for a high power optical parametric oscillation generation. The current work can be extended to an experiment employing the fundamental Nd:YAG as pump to provide a coherent light source for the study of molecular vibrations. 28 refs., 14 figs., 3 tabs. (Author)

Underground structure characterization using motor vehicles as passive seismic sources

Science.gov (United States)

Kuzma, H. A.; Liu, Y.; Zhao, Y.; Rector, J.; Vaidya, S.

2009-12-01

The ability to detect and characterize underground voids will be critical to the success of On-Site Inspections (OSI) as mandated by the nuclear Comprehensive Test Ban Treaty (CTBT). OSIs may be conducted in order to successfully locate the Ground Zero of underground tests as well as infrastructure related to testing. Recently, our team has shown the potential of a new technique to detect underground objects using the amplitude of seismic surface waves generated by motor vehicles. In an experiment conducted in June, 2009 we were able to detect an abandoned railroad tunnel by recognizing a clear pattern in the surface waves scattered by the tunnel, using a signal generated by driving a car on a dirt road across the tunnel. Synthetic experiments conducted using physically realistic wave-equation models further suggest that the technique can be readily applied to detecting underground features: it may be possible to image structures of importance to OSI simply by laying out an array of geophones (or using an array already in place for passive listening for event aftershocks) and driving vehicles around the site. We present evidence from a set of field experiments and from synthetic modeling and inversion studies to illustrate adaptations of the technique for OSI. Signature of an abandoned underground railroad tunnel at Donner Summit, CA. To produce this image, a line of geophones was placed along a dirt road perpendicular to the tunnel (black box) and a single car was driven along the road. A normalized mean power-spectrum is displayed on a log scale as a function of meters from the center of the tunnel. The top of the tunnel was 18m below ground surface. The tunnel anomaly is made up of a shadow (light) directly above the tunnel and amplitude build-up (dark) on either side of the tunnel. The size of the anomaly (6 orders of magnitude) suggests that the method can be extended to find deep structures at greater distances from the source and receivers.

Characterization of Organic Matter Sources within a Matrix of Land Use in Northeast Utah

Science.gov (United States)

Kelso, J. E.; Baker, M. A.

2017-12-01

Dynamics of organic matter (OM) sources in natural aquatic systems have been studied for decades, but urban studies have revealed additional, less studied, OM sources such as stormwater, lawn clippings, and wastewater effluent. Traditionally the OM pool in freshwater systems has been defined as a homogenous pool of varying size classes: course particulate, fine particulate and dissolved OM. Our goal was to identify and quantify the composition of fine particulate OM (FPOM), and dissolved OM (DOM) as derived from autochthonous, terrestrial, and potential anthropogenic sources. We hypothesized anthropogenic changes in land use have increased the proportion of autochthonous sources of OM. We sampled OM at 33 sites in four watersheds in northeast Utah that encompass a range of land uses. Stable isotopes of carbon, nitrogen, and deuterium were collected for all size classes of OM, and DOM was analyzed with a spectrofluorometer. Stable isotopes were used to estimate the proportion of autochthonous and terrestrial sources of OM. Fluorescence indices and a PARAFAC model were created from DOM excitation emission matrices (EEMs). FPOM appeared to be a mixture of autochthonous and terrestrial sources but overlap in endmember isotope values made quantifying the proportion of each source difficult. Higher deuterium values (-120 to -80‰) were associated with sites receiving wastewater effluent, while sites with agriculture, forest, and urban land use had lower deuterium isotope values (-200 to -110). DOM Excitation Emission Matrices were resolved into a 5-component PARAFAC model. The percent of protein-like DOM components tended to be higher in urban versus non-urban sites (mean 35%, S.D. 12% versus mean 25%, S.D. 15%). We concluded deuterium isotopes may be used as a tracer or wastewater effluent and DOM is composed of more labile, protein-like DOM with increased wastewater input. A greater understanding of the sources of OM can inform management and policy decisions aimed at

Characterization of Biosurfactant Produced during Degradation of Hydrocarbons Using Crude Oil As Sole Source of Carbon.

Science.gov (United States)

Patowary, Kaustuvmani; Patowary, Rupshikha; Kalita, Mohan C; Deka, Suresh

2017-01-01

Production and spillage of petroleum hydrocarbons which is the most versatile energy resource causes disastrous environmental pollution. Elevated oil degrading performance from microorganisms is demanded for successful microbial remediation of those toxic pollutants. The employment of biosurfactant-producing and hydrocarbon-utilizing microbes enhances the effectiveness of bioremediation as biosurfactant plays a key role by making hydrocarbons bio-available for degradation. The present study aimed the isolation of a potent biosurfactant producing indigenous bacteria which can be employed for crude oil remediation, along with the characterization of the biosurfactant produced during crude oil biodegradation. A potent bacterial strain Pseudomonas aeruginosa PG1 (identified by 16s rDNA sequencing) was isolated from hydrocarbon contaminated soil that could efficiently produce biosurfactant by utilizing crude oil components as the carbon source, thereby leading to the enhanced degradation of the petroleum hydrocarbons. Strain PG1 could degrade 81.8% of total petroleum hydrocarbons (TPH) after 5 weeks of culture when grown in mineral salt media (MSM) supplemented with 2% (v/v) crude oil as the sole carbon source. GCMS analysis of the treated crude oil samples revealed that P. aeruginosa PG1 could potentially degrade various hydrocarbon contents including various PAHs present in the crude oil. Biosurfactant produced by strain PG1 in the course of crude oil degradation, promotes the reduction of surface tension (ST) of the culture medium from 51.8 to 29.6 mN m -1 , with the critical micelle concentration (CMC) of 56 mg L -1 . FTIR, LC-MS, and SEM-EDS studies revealed that the biosurfactant is a rhamnolipid comprising of both mono and di rhamnolipid congeners. The biosurfactant did not exhibit any cytotoxic effect to mouse L292 fibroblastic cell line, however, strong antibiotic activity against some pathogenic bacteria and fungus was observed.

Characterization of Biosurfactant Produced during Degradation of Hydrocarbons Using Crude Oil As Sole Source of Carbon

Science.gov (United States)

Patowary, Kaustuvmani; Patowary, Rupshikha; Kalita, Mohan C.; Deka, Suresh

2017-01-01

Production and spillage of petroleum hydrocarbons which is the most versatile energy resource causes disastrous environmental pollution. Elevated oil degrading performance from microorganisms is demanded for successful microbial remediation of those toxic pollutants. The employment of biosurfactant-producing and hydrocarbon-utilizing microbes enhances the effectiveness of bioremediation as biosurfactant plays a key role by making hydrocarbons bio-available for degradation. The present study aimed the isolation of a potent biosurfactant producing indigenous bacteria which can be employed for crude oil remediation, along with the characterization of the biosurfactant produced during crude oil biodegradation. A potent bacterial strain Pseudomonas aeruginosa PG1 (identified by 16s rDNA sequencing) was isolated from hydrocarbon contaminated soil that could efficiently produce biosurfactant by utilizing crude oil components as the carbon source, thereby leading to the enhanced degradation of the petroleum hydrocarbons. Strain PG1 could degrade 81.8% of total petroleum hydrocarbons (TPH) after 5 weeks of culture when grown in mineral salt media (MSM) supplemented with 2% (v/v) crude oil as the sole carbon source. GCMS analysis of the treated crude oil samples revealed that P. aeruginosa PG1 could potentially degrade various hydrocarbon contents including various PAHs present in the crude oil. Biosurfactant produced by strain PG1 in the course of crude oil degradation, promotes the reduction of surface tension (ST) of the culture medium from 51.8 to 29.6 mN m−1, with the critical micelle concentration (CMC) of 56 mg L−1. FTIR, LC-MS, and SEM-EDS studies revealed that the biosurfactant is a rhamnolipid comprising of both mono and di rhamnolipid congeners. The biosurfactant did not exhibit any cytotoxic effect to mouse L292 fibroblastic cell line, however, strong antibiotic activity against some pathogenic bacteria and fungus was observed. PMID:28275373

A Dosimetric Characterization of the 137Cs Brachytherapy source to be used in Libyan Medical Centers

International Nuclear Information System (INIS)

Giaddui, T.; Eshaibani, R.; Assatel, O.

2007-01-01

A dosimetric characterization of the 137C s brachytherapy source to be used in Libyan medical centers was carried out using analytical and Monte Carlo investigations. The dose rates in air across the transverse axis were calculated using a Monte Carlo Code and the Sievert integral method. A good agreement between the results was achieved. The Monte Carlo Code was then used to calculate the two dimensional dose rates in water and isodose curves were generated. The latter results were used to calculate the dose rate at the reference point, radial dose function and the anisotropy function according to the American Association of Physicist in Medicine (AAPM) TG.43 formalism .

Studies and modeling of cold neutron sources; Etude et modelisation des sources froides de neutron

Energy Technology Data Exchange (ETDEWEB)

Campioni, G

2004-11-15

With the purpose of updating knowledge in the fields of cold neutron sources, the work of this thesis has been run according to the 3 following axes. First, the gathering of specific information forming the materials of this work. This set of knowledge covers the following fields: cold neutron, cross-sections for the different cold moderators, flux slowing down, different measurements of the cold flux and finally, issues in the thermal analysis of the problem. Secondly, the study and development of suitable computation tools. After an analysis of the problem, several tools have been planed, implemented and tested in the 3-dimensional radiation transport code Tripoli-4. In particular, a module of uncoupling, integrated in the official version of Tripoli-4, can perform Monte-Carlo parametric studies with a spare factor of Cpu time fetching 50 times. A module of coupling, simulating neutron guides, has also been developed and implemented in the Monte-Carlo code McStas. Thirdly, achieving a complete study for the validation of the installed calculation chain. These studies focus on 3 cold sources currently functioning: SP1 from Orphee reactor and 2 other sources (SFH and SFV) from the HFR at the Laue Langevin Institute. These studies give examples of problems and methods for the design of future cold sources.

GLOBAL SOURCING: A THEORETICAL STUDY ON TURKEY

Directory of Open Access Journals (Sweden)

Aytac GOKMEN

2010-07-01

Full Text Available Global sourcing is to source from the global market for goods and services across national boundaries in order to take advantage of the global efficiencies in the delivery of a product or service. Such efficiencies are consists of low cost skilled labor, low cost raw materials and other economic factors like tax breaks and deductions as well as low trade tariffs. When we assess the case regarding to Turkey, global sourcing is an effective device for some firms. The domestic firms in Turkey at various industries are inclined to global source finished or intermediate goods from the world markets, finish the production process in Turkey and export. Eventually, on the one hand the export volume of Turkey increases, but on the other hand the import of a considerable volume of finished or intermediate goods bring about a negative trade balance and loss of jobs in Turkey. Therefore, the objective of this study is to assess the concept of global sourcing transactions on Turkey resting on comprehensive publications.

Comparative studies of energy sources in gynecologic laparoscopy.

Science.gov (United States)

Law, Kenneth S K; Lyons, Stephen D

2013-01-01

Energy sources incorporating "vessel sealing" capabilities are being increasingly used in gynecologic laparoscopic surgery although conventional monopolar and bipolar electrosurgery remain popular. The preference for one device over another is based on a combination of factors, including the surgeon's subjective experience, availability, and cost. Although comparative clinical studies and meta-analyses of laparoscopic energy sources have reported small but statistically significant differences in volumes of blood loss, the clinical significance of such small volumes is questionable. The overall usefulness of the various energy sources available will depend on a number of factors including vessel burst pressure and seal time, lateral thermal spread, and smoke production. Animal studies and laboratory-based trials are useful in providing a controlled environment to investigate such parameters. At present, there is insufficient evidence to support the use of one energy source over another. Copyright © 2013 AAGL. All rights reserved.

Source characterization and dynamic fault modeling of induced seismicity

Science.gov (United States)

Lui, S. K. Y.; Young, R. P.

2017-12-01

In recent years there are increasing concerns worldwide that industrial activities in the sub-surface can cause or trigger damaging earthquakes. In order to effectively mitigate the damaging effects of induced seismicity, the key is to better understand the source physics of induced earthquakes, which still remain elusive at present. Furthermore, an improved understanding of induced earthquake physics is pivotal to assess large-magnitude earthquake triggering. A better quantification of the possible causes of induced earthquakes can be achieved through numerical simulations. The fault model used in this study is governed by the empirically-derived rate-and-state friction laws, featuring a velocity-weakening (VW) patch embedded into a large velocity-strengthening (VS) region. Outside of that, the fault is slipping at the background loading rate. The model is fully dynamic, with all wave effects resolved, and is able to resolve spontaneous long-term slip history on a fault segment at all stages of seismic cycles. An earlier study using this model has established that aseismic slip plays a major role in the triggering of small repeating earthquakes. This study presents a series of cases with earthquakes occurring on faults with different fault frictional properties and fluid-induced stress perturbations. The effects to both the overall seismicity rate and fault slip behavior are investigated, and the causal relationship between the pre-slip pattern prior to the event and the induced source characteristics is discussed. Based on simulation results, the subsequent step is to select specific cases for laboratory experiments which allow well controlled variables and fault parameters. Ultimately, the aim is to provide better constraints on important parameters for induced earthquakes based on numerical modeling and laboratory data, and hence to contribute to a physics-based induced earthquake hazard assessment.

ITER Safety Task NID-5A, Subtask 1-1: Source terms and energies - initial tritium source terms. Final report

International Nuclear Information System (INIS)

Fong, C.; Kalyanam, K.M.; Tanaka, M.R.; Sood, S.; Natalizio, A.; Delisle, M.

1995-02-01

The overall objective of the Early Safety and Environmental Characterization Study (ESECS) is to assess the environmental impact of tritium using appropriate assumptions on a hypothetical site for ITER, having the r eference s ite characteristics as proposed by the JCT. The objective of this work under the above subtask 1-1, NID-5a, is to determine environmental source terms (i.e., process source term x containment release fraction) for the fuel cycle and cooling systems. The work is based on inventories and process source terms (i.e., inventory x mobilization fraction), provided by others (under Task NID 3b). The results of this work form the basis for the determination, by others, of the off-site dose (i.e., environmental source term x dose/release ratio). For the determination of the environmental source terms, the TMAP4 code has been utilized (ref 1). This code is approved by ITER for safety assessment. Volume 3 is a compilation of appendices giving detailed results of the study

Characterization of the primary source of electrons in linear accelerators in clinical use; Caracterizacion de la fuente primaria de electrones en aceleradores lineales de uso clinico

Energy Technology Data Exchange (ETDEWEB)

Gomez Extremera, M.; Gonzalez Infantes, W.; Lallena rojo, A. M.; Anguiano Millan, M.

2013-07-01

Monte Carlo simulation is currently considered the most accurate method for calculations of doses due to electrons. The objective of the work is the characterization of the primary source of electrons from an accelerator of clinical use with Monte Carlo simulation, in order to build a model of sources involving a substantial saving of time of calculation in the simulation of treatment. (Author)

Stationary chest tomosynthesis using a carbon nanotube x-ray source array: a feasibility study

International Nuclear Information System (INIS)

Shan, Jing; Lee, Yueh Z; Lu, Jianping; Zhou, Otto; Tucker, Andrew W; Heath, Michael D; Wang, Xiaohui; Foos, David H

2015-01-01

Chest tomosynthesis is a low-dose, quasi-3D imaging modality that has been demonstrated to improve the detection sensitivity for small lung nodules, compared to 2D chest radiography. The purpose of this study is to investigate the feasibility and system requirements of stationary chest tomosynthesis (s-DCT) using a spatially distributed carbon nanotube (CNT) x-ray source array, where the projection images are collected by electronically activating individual x-ray focal spots in the source array without mechanical motion of the x-ray source, detector, or the patient. A bench-top system was constructed using an existing CNT field emission source array and a flat panel detector. The tube output, beam quality, focal spot size, system in-plane and in-depth resolution were characterized. Tomosynthesis slices of an anthropomorphic chest phantom were reconstructed for image quality assessment. All 75 CNT sources in the source array were shown to operate reliably at 80 kVp and 5 mA tube current. Source-to-source consistency in the tube current and focal spot size was observed. The incident air kerma reading per mAs was measured as 74.47 uGy mAs −1 at 100 cm. The first half value layer of the beam was 3 mm aluminum. An average focal spot size of 2.5  ×  0.5 mm was measured. The system MTF was measured to be 1.7 cycles mm −1 along the scanning direction, and 3.4 cycles mm −1 perpendicular to the scanning direction. As the angular coverage of 11.6°–34°, the full width at half maximum of the artifact spread function improved greatly from 9.5 to 5.2 mm. The reconstructed tomosynthesis slices clearly show airways and pulmonary vascular structures in the anthropomorphic lung phantom. The results show the CNT source array is capable of generating sufficient dose for chest tomosynthesis imaging. The results obtained so far suggest an s-DCT using a distributed CNT x-ray source array is feasible. (paper)

An ion cooling and state characterization apparatus for studies of molecular ion dissociative interactions

International Nuclear Information System (INIS)

Deng, Shihu; Vane, C R; Bannister, M E; Havener, C C; Meyer, F W; Krause, H F; Hettich, R L; Goeringer, D E; Van Berkel, G J

2009-01-01

An experimental capability is being developed at the Oak Ridge National Laboratory Multi-Charged Ion Research Facility (ORNL MIRF) to enable stored cooling and state characterization of molecular ions of essentially any mass. Ions selected from a variety of available sources are injected from the side into a 1.5 meter long electrostatic mirror trap, where excited internal states are cooled by radiative cooling. An electron beam target located near the middle of the ion-trap region, coupled with neutral fragment imaging detector systems at each end of the trap, permits state-specific studies of electron-molecular ion dissociation.

Seasonal behavior of carbonyls and source characterization of formaldehyde (HCHO) in ambient air

Science.gov (United States)

Lui, K. H.; Ho, Steven Sai Hang; Louie, Peter K. K.; Chan, C. S.; Lee, S. C.; Hu, Di; Chan, P. W.; Lee, Jeffrey Chi Wai; Ho, K. F.

2017-03-01

Gas-phase formaldehyde (HCHO) is an intermediate and a sensitive indicator for volatile organic compounds (VOCs) oxidation, which drives tropospheric ozone production. Effective photochemical pollution control strategies demand a thorough understanding of photochemical oxidation precursors, making differentiation between sources of primary and secondary generated HCHO inevitable. Spatial and seasonal variations of airborne carbonyls based on two years of measurements (2012-2013), coupled with a correlation-based HCHO source apportionment analysis, were determined for three sampling locations in Hong Kong (denoted HT, TC, and YL). Formaldehyde and acetaldehyde were the two most abundant compounds of the total quantified carbonyls. Pearson's correlation analysis (r > 0.7) implies that formaldehyde and acetaldehyde possibly share similar sources. The total carbonyl concentration trends (HT rural). A regression analysis further quantifies the relative primary HCHO source contributions at HT (∼13%), TC (∼21%), and YL (∼40%), showing more direct vehicular emissions in urban than rural areas. Relative secondary source contributions at YL (∼36%) and TC (∼31%) resemble each other, implying similar urban source contributions. Relative background source contributions at TC could be due to a closed structure microenvironment that favors the trapping of HCHO. Comparable seasonal differences are observed at all stations. The results of this study will aid in the development of a new regional ozone (O3) control policy, as ambient HCHO can enhance O3 production and also be produced from atmospheric VOCs oxidation (secondary HCHO).

Fecal pollution source tracking toolbox for identification, evaluation and characterization of fecal contamination in receiving urban surface waters and groundwater.

Science.gov (United States)

Tran, Ngoc Han; Gin, Karina Yew-Hoong; Ngo, Huu Hao

2015-12-15

The quality of surface waters/groundwater of a geographical region can be affected by anthropogenic activities, land use patterns and fecal pollution sources from humans and animals. Therefore, the development of an efficient fecal pollution source tracking toolbox for identifying the origin of the fecal pollution sources in surface waters/groundwater is especially helpful for improving management efforts and remediation actions of water resources in a more cost-effective and efficient manner. This review summarizes the updated knowledge on the use of fecal pollution source tracking markers for detecting, evaluating and characterizing fecal pollution sources in receiving surface waters and groundwater. The suitability of using chemical markers (i.e. fecal sterols, fluorescent whitening agents, pharmaceuticals and personal care products, and artificial sweeteners) and/or microbial markers (e.g. F+RNA coliphages, enteric viruses, and host-specific anaerobic bacterial 16S rDNA genetic markers) for tracking fecal pollution sources in receiving water bodies is discussed. In addition, this review also provides a comprehensive approach, which is based on the detection ratios (DR), detection frequencies (DF), and fate of potential microbial and chemical markers. DR and DF are considered as the key criteria for selecting appropriate markers for identifying and evaluating the impacts of fecal contamination in surface waters/groundwater. Copyright © 2015 Elsevier B.V. All rights reserved.

Characterization of an electrothermal plasma source for fusion transient simulations

Science.gov (United States)

Gebhart, T. E.; Baylor, L. R.; Rapp, J.; Winfrey, A. L.

2018-01-01

The realization of fusion energy requires materials that can withstand high heat and particle fluxes at the plasma material interface. In this work, an electrothermal (ET) plasma source has been designed as a transient heat flux source for a linear plasma material interaction device. An ET plasma source operates in the ablative arc regime driven by a DC capacitive discharge. The current channel width is defined by the 4 mm bore of a boron nitride liner. At large plasma currents, the arc impacts the liner wall, leading to high particle and heat fluxes to the liner material, which subsequently ablates and ionizes. This results in a high density plasma with a large unidirectional bulk flow out of the source exit. The pulse length for the ET source has been optimized using a pulse forming network to have durations of 1 and 2 ms. The peak currents and maximum source energies seen in this system are 1.9 kA and 1.2 kJ for the 2 ms pulse and 3.2 kA and 2.1 kJ for the 1 ms pulse, respectively. This work is a proof of the principal project to show that an ET source produces electron densities and heat fluxes comparable to those anticipated in transient events in large future magnetic confinement fusion devices. Heat flux, plasma temperature, and plasma density were determined for each shot using infrared imaging and optical spectroscopy techniques. This paper will discuss the assumptions, methods, and results of the experiments.

Sustainability in Open Source Software Commons: Lessons Learned from an Empirical Study of SourceForge Projects

Directory of Open Access Journals (Sweden)

Charles M. Schweik

2013-01-01

Full Text Available In this article, we summarize a five-year US National Science Foundation funded study designed to investigate the factors that lead some open source projects to ongoing collaborative success while many others become abandoned. Our primary interest was to conduct a study that was closely representative of the population of open source software projects in the world, rather than focus on the more-often studied, high-profile successful cases. After building a large database of projects (n=174,333 and implementing a major survey of open source developers (n=1403, we were able to conduct statistical analyses to investigate over forty theoretically-based testable hypotheses. Our data firmly support what we call the conventional theory of open source software, showing that projects start small, and, in successful cases, grow slightly larger in terms of team size. We describe the “virtuous circle” supporting conventional wisdom of open source collaboration that comes out of this analysis, and we discuss two other interesting findings related to developer motivations and how team members find each other. Each of these findings is related to the sustainability of these projects.

The Source Inversion Validation (SIV) Initiative: A Collaborative Study on Uncertainty Quantification in Earthquake Source Inversions

Science.gov (United States)

Mai, P. M.; Schorlemmer, D.; Page, M.

2012-04-01

Earthquake source inversions image the spatio-temporal rupture evolution on one or more fault planes using seismic and/or geodetic data. Such studies are critically important for earthquake seismology in general, and for advancing seismic hazard analysis in particular, as they reveal earthquake source complexity and help (i) to investigate earthquake mechanics; (ii) to develop spontaneous dynamic rupture models; (iii) to build models for generating rupture realizations for ground-motion simulations. In applications (i - iii), the underlying finite-fault source models are regarded as "data" (input information), but their uncertainties are essentially unknown. After all, source models are obtained from solving an inherently ill-posed inverse problem to which many a priori assumptions and uncertain observations are applied. The Source Inversion Validation (SIV) project is a collaborative effort to better understand the variability between rupture models for a single earthquake (as manifested in the finite-source rupture model database) and to develop robust uncertainty quantification for earthquake source inversions. The SIV project highlights the need to develop a long-standing and rigorous testing platform to examine the current state-of-the-art in earthquake source inversion, and to develop and test novel source inversion approaches. We will review the current status of the SIV project, and report the findings and conclusions of the recent workshops. We will briefly discuss several source-inversion methods, how they treat uncertainties in data, and assess the posterior model uncertainty. Case studies include initial forward-modeling tests on Green's function calculations, and inversion results for synthetic data from spontaneous dynamic crack-like strike-slip earthquake on steeply dipping fault, embedded in a layered crustal velocity-density structure.

A New Database Facilitates Characterization of Flavonoid Intake, Sources, and Positive Associations with Diet Quality among US Adults.

Science.gov (United States)

Sebastian, Rhonda S; Wilkinson Enns, Cecilia; Goldman, Joseph D; Martin, Carrie L; Steinfeldt, Lois C; Murayi, Theophile; Moshfegh, Alanna J

2015-06-01

Epidemiologic studies demonstrate inverse associations between flavonoid intake and chronic disease risk. However, lack of comprehensive databases of the flavonoid content of foods has hindered efforts to fully characterize population intakes and determine associations with diet quality. Using a newly released database of flavonoid values, this study sought to describe intake and sources of total flavonoids and 6 flavonoid classes and identify associations between flavonoid intake and the Healthy Eating Index (HEI) 2010. One day of 24-h dietary recall data from adults aged ≥ 20 y (n = 5420) collected in What We Eat in America (WWEIA), NHANES 2007-2008, were analyzed. Flavonoid intakes were calculated using the USDA Flavonoid Values for Survey Foods and Beverages 2007-2008. Regression analyses were conducted to provide adjusted estimates of flavonoid intake, and linear trends in total and component HEI scores by flavonoid intake were assessed using orthogonal polynomial contrasts. All analyses were weighted to be nationally representative. Mean intake of flavonoids was 251 mg/d, with flavan-3-ols accounting for 81% of intake. Non-Hispanic whites had significantly higher (P empty calories increased (P < 0.001) across flavonoid intake quartiles. A new database that permits comprehensive estimation of flavonoid intakes in WWEIA, NHANES 2007-2008; identification of their major food/beverage sources; and determination of associations with dietary quality will lead to advances in research on relations between flavonoid intake and health. Findings suggest that diet quality, as measured by HEI, is positively associated with flavonoid intake. © 2015 American Society for Nutrition.

Robust remediation strategies at gas-work sites: a case of source recognition and source characterization

International Nuclear Information System (INIS)

Vries, P.O. de

2005-01-01

In The Netherlands there have been gasworks at about 260 to 270 locations. Most of these locations are or were heavily polluted with tar, ashes and cyanides and many of them belong to the locations where remediation actions have already been executed. It seems however that many of them also belong to the locations where remediation actions were not quite as successful as was expected. So, for many gas-work sites that were already 'remedied' in the 80's and early 90's of the foregoing century, new programs for site remediation are planned. Of course the mistakes from the past should now be avoided. The current remediation strategy in The Netherlands for gas-work sites can be comprised in four steps: 1 - removing spots in the top soil, 2 - removing spots with mobile components in the shallow subsoil, 3 - controlling spots with mobile components in the deep subsoil, 4 - creating a 'steady endpoint situation' in the plume. At many former gas-work sites real sources, i.e. in a physico-chemical sense, are not very well known. This can easily lead to insufficient removal of some or part of these sources and cause a longer delivery of contaminants to the groundwater plume, with higher endpoint concentrations, higher costs and more restrictions for future use. The higher concentrations and longer deliveries originating from not recognized or not localized sources are often not sufficiently compensated by the proposed plume management in current remediation strategies. Remediation results can be improved by using knowledge about the processes that determine the delivery of contaminants to the groundwater, the materials that cause these delivery and the locations at the site where these are most likely found. When sources are present in the deep subsoil or the exact localization of sources is uncertain, robust remediation strategies should be chosen and wishful thinking about removing sources with in situ techniques should be avoided. Robust strategies are probably less

Sealed source and device removal and consolidation feasibility study

International Nuclear Information System (INIS)

Ward, J.E.; Carter, J.G.; Meyers, R.L.

1993-02-01

The purpose of this study is to assess the feasibility of removing Greater-Than-Class C (GTCC) sealed sources from their containment device and consolidating them for transport to a storage or disposal facility. A sealed source is a sealed capsule containing a radioactive material that is placed in a device providing radioactive containment. It is used in the medical, industrial, research, and food-processing communities for calibrating, measuring, gauging, controlling processes, and testing. This feasibility study addresses the key operational, safety, regulatory, and financial requirements of the removal/consolidation process. This report discusses the process to receive, handle, repackage, and ship these sources to an interim or dedicated storage facility until a final disposal repository can be built and become operational (∼ c. 2010). The study identifies operational and facility requirements to perform this work. Hanford, other DOE facilities, and private hot-cell facilities were evaluated to determine which facilities could perform this work. The personnel needed, design and engineering, facility preparation, process waste disposal requirements, and regulatory compliance were evaluated to determine the cost to perform this work. Cost requirements for items that will have to meet future changing regulatory requirements for transportation, transportation container design and engineering, and disposal were not included in this study. The cost associated with in-process consolidation of the sealed sources reported in this study may have not been modified for inflation and were based on 1992 dollars. This study shows that sealed source consolidation is possible with minimal personnel exposure, and would reduce the risk of radioactive releases to the environment. An initial pilot-scale operation could evaluate the possible methods to reduce the cost and consolidate sources

Characterization of occurrence, sources and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in a tropical urban catchment

International Nuclear Information System (INIS)

Chen, Huiting; Reinhard, Martin; Nguyen, Tung Viet; You, Luhua; He, Yiliang; Gin, Karina Yew-Hoong

2017-01-01

. - Highlights: • Dominant species in water: PFBS, PFBA, PFOS and PFOA. • Solution phase concentrations are govern by compound hydrophobicity and sorption to suspended particles. • Dominant species in sediment: EtFOSAA, PFDoA, PFOS and PFDA. • C8/C8 PFPIA, PFDoA and PFUnA: Intermittent point sources; FOSAMs and PFOS: Continuous non-point sources. - Occurrence, sources and sinks of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in a tropical urban catchment were characterized.

SU-F-BRA-09: New Efficient Method for Xoft Axxent Electronic Brachytherapy Source Calibration by Pre-Characterizing Surface Applicators

Energy Technology Data Exchange (ETDEWEB)

Pai, S [iCAD Inc., Los Gatos, CA (United States)

2015-06-15

Purpose: The objective is to improve the efficiency and efficacy of Xoft™ Axxent™ electronic brachytherapy (EBT) calibration of the source & surface applicator using AAPM TG-61 formalism. Methods: Current method of Xoft EBT source calibration involves determination of absolute dose rate of the source in each of the four conical surface applicators using in-air chamber measurements & TG61 formalism. We propose a simplified TG-61 calibration methodology involving initial characterization of surface cone applicators. This is accomplished by calibrating dose rates for all 4 surface applicator sets (for 10 sources) which establishes the “applicator output ratios” with respect to the selected reference applicator (20 mm applicator). After the initial time, Xoft™ Axxent™ source TG61 Calibration is carried out only in the reference applicator. Using the established applicator output ratios, dose rates for other applicators will be calculated. Results: 200 sources & 8 surface applicator sets were calibrated cumulatively using a Standard Imaging A20 ion-chamber in accordance with manufacturer-recommended protocols. Dose rates of 10, 20, 35 & 50mm applicators were normalized to the reference (20mm) applicator. The data in Figure 1 indicates that the normalized dose rate variation for each applicator for all 200 sources is better than ±3%. The average output ratios are 1.11, 1.02 and 0.49 for the 10 mm,35 mm and 50 mm applicators, respectively, which are in good agreement with the manufacturer’s published output ratios of 1.13, 1.02 and 0.49. Conclusion: Our measurements successfully demonstrate the accuracy of a new calibration method using a single surface applicator for Xoft EBT sources and deriving the dose rates of other applicators. The accuracy of the calibration is improved as this method minimizes the source position variation inside the applicator during individual source calibrations. The new method significantly reduces the calibration time to less

Femtosecond electron bunches, source and characterization

International Nuclear Information System (INIS)

Thongbai, C.; Kusoljariyakul, K.; Rimjaem, S.; Rhodes, M.W.; Saisut, J.; Thamboon, P.; Wichaisirimongkol, P.; Vilaithong, T.

2008-01-01

A femtosecond electron source has been developed at the Fast Neutron Research Facility (FNRF), Chiang Mai University, Thailand. So far, it has produced electron bunches as short as σ z ∼180 fs with (1-6)x10 8 electrons per microbunch. The system consists of an RF-gun with a thermionic cathode, an alpha-magnet as a magnetic bunch compressor, and a linear accelerator as a post acceleration section. Coherent transition radiation emitted at wavelengths equal to and longer than the bunch length is used in a Michelson interferometer to determine the bunch length by autocorrelation technique. The experimental setup and results of the bunch length measurement are described

The State of Open Source Electronic Health Record Projects: A Software Anthropology Study.

Science.gov (United States)

Alsaffar, Mona; Yellowlees, Peter; Odor, Alberto; Hogarth, Michael

2017-02-24

Electronic health records (EHR) are a key tool in managing and storing patients' information. Currently, there are over 50 open source EHR systems available. Functionality and usability are important factors for determining the success of any system. These factors are often a direct reflection of the domain knowledge and developers' motivations. However, few published studies have focused on the characteristics of free and open source software (F/OSS) EHR systems and none to date have discussed the motivation, knowledge background, and demographic characteristics of the developers involved in open source EHR projects. This study analyzed the characteristics of prevailing F/OSS EHR systems and aimed to provide an understanding of the motivation, knowledge background, and characteristics of the developers. This study identified F/OSS EHR projects on SourceForge and other websites from May to July 2014. Projects were classified and characterized by license type, downloads, programming languages, spoken languages, project age, development status, supporting materials, top downloads by country, and whether they were "certified" EHRs. Health care F/OSS developers were also surveyed using an online survey. At the time of the assessment, we uncovered 54 open source EHR projects, but only four of them had been successfully certified under the Office of the National Coordinator for Health Information Technology (ONC Health IT) Certification Program. In the majority of cases, the open source EHR software was downloaded by users in the United States (64.07%, 148,666/232,034), underscoring that there is a significant interest in EHR open source applications in the United States. A survey of EHR open source developers was conducted and a total of 103 developers responded to the online questionnaire. The majority of EHR F/OSS developers (65.3%, 66/101) are participating in F/OSS projects as part of a paid activity and only 25.7% (26/101) of EHR F/OSS developers are, or have been

Non-uniform dispersion of the source-sink relationship alters wavefront curvature.

Directory of Open Access Journals (Sweden)

Lucia Romero

Full Text Available The distribution of cellular source-sink relationships plays an important role in cardiac propagation. It can lead to conduction slowing and block as well as wave fractionation. It is of great interest to unravel the mechanisms underlying evolution in wavefront geometry. Our goal is to investigate the role of the source-sink relationship on wavefront geometry using computer simulations. We analyzed the role of variability in the microscopic source-sink relationship in driving changes in wavefront geometry. The electrophysiological activity of a homogeneous isotropic tissue was simulated using the ten Tusscher and Panfilov 2006 action potential model and the source-sink relationship was characterized using an improved version of the Romero et al. safety factor formulation (SFm2. Our simulations reveal that non-uniform dispersion of the cellular source-sink relationship (dispersion along the wavefront leads to alterations in curvature. To better understand the role of the source-sink relationship in the process of wave formation, the electrophysiological activity at the initiation of excitation waves in a 1D strand was examined and the source-sink relationship was characterized using the two recently updated safety factor formulations: the SFm2 and the Boyle-Vigmond (SFVB definitions. The electrophysiological activity at the initiation of excitation waves was intimately related to the SFm2 profiles, while the SFVB led to several counterintuitive observations. Importantly, with the SFm2 characterization, a critical source-sink relationship for initiation of excitation waves was identified, which was independent of the size of the electrode of excitation, membrane excitability, or tissue conductivity. In conclusion, our work suggests that non-uniform dispersion of the source-sink relationship alters wavefront curvature and a critical source-sink relationship profile separates wave expansion from collapse. Our study reinforces the idea that the

Noise study of all-normal dispersion supercontinuum sources for potential application in optical coherence tomography

Science.gov (United States)

Gonzalo, I. B.; Engelsholm, R. D.; Bang, O.

2018-03-01

Commercially available silica-fiber-based and ultra-broadband supercontinuum (SC) sources are typically generated by pumping close to the zero-dispersion wavelength (ZDW) of a photonic crystal fiber (PCF), using high-power picosecond or nanosecond laser pulses. Despite the extremely broad bandwidths, such sources are characterized by large intensity fluctuations, limiting their performance for applications in imaging such as optical coherence tomography (OCT). An approach to eliminate the influence of noise sensitive effects is to use a so-called all-normal dispersion (ANDi) fiber, in which the dispersion is normal for all the wavelengths of interest. Pumping these types of fibers with short enough femtosecond pulses allows to suppress stimulated Raman scattering (SRS), which is known to be as noisy process as modulation instability (MI), and coherent SC is generated through self-phase modulation (SPM) and optical wave breaking (OWB). In this study, we show the importance of the pump laser and fiber parameters in the design of low-noise ANDi based SC sources, for application in OCT. We numerically investigate the pulse-to-pulse fluctuations of the SC, calculating the relative intensity noise (RIN) as a function of the pump pulse duration and fiber length. Furthermore, we experimentally demonstrate the role of the fiber length on the RIN of the ANDi SC, validating the results calculated numerically. In the end, we compare the RIN of a commercial SC source based on MI and the ANDi SC source developed here, which shows better noise performance when it is carefully designed.

A systematic review characterizing on-farm sources of Campylobacter spp. for broiler chickens.

Directory of Open Access Journals (Sweden)

Agnes Agunos

Full Text Available Campylobacter and antimicrobial-resistant Campylobacter are frequently isolated from broiler chickens worldwide. In Canada, campylobacteriosis is the third leading cause of enteric disease and the regional emergence of ciprofloxacin-resistant Campylobacter in broiler chickens has raised a public health concern. This study aimed to identify, critically appraise, and synthesize literature on sources of Campylobacter in broilers at the farm level using systematic review methodology. Literature searches were conducted in January 2012 and included electronic searches in four bibliographic databases. Relevant studies in French or English (n = 95 conducted worldwide in any year and all study designs were included. Risk of Bias and GRADE criteria endorsed by the Cochrane collaboration was used to assess the internal validity of the study and overall confidence in the meta-analysis. The categories for on-farm sources were: broiler breeders/vertical transfer (number of studies = 32, animals (n = 57, humans (n = 26, environment (n = 54, and water (n = 63. Only three studies examined the antimicrobial resistance profiles of Campylobacter from these on-farm sources. Subgroups of data by source and outcome were analyzed using random effect meta-analysis. The highest risk for contaminating a new flock appears to be a contaminated barn environment due to insufficient cleaning and disinfection, insufficient downtime, and the presence of an adjacent broiler flock. Effective biosecurity enhancements from physical barriers to restricting human movement on the farm are recommended for consideration to enhance local on-farm food safety programs. Improved sampling procedures and standardized laboratory testing are needed for comparability across studies. Knowledge gaps that should be addressed include farm-level drug use and antimicrobial resistance information, further evaluation of the potential for vertical transfer, and improved genotyping

Characterization of electron temperature by simulating a multicusp ion source

Energy Technology Data Exchange (ETDEWEB)

Yeon, Yeong Heum [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Lee, Jong Chul; Mohamed Gad, Khaled Mohamed [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Namgoong, Ho [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Chai, Jong Seo, E-mail: jschai@skku.edu [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of)

2016-12-01

Multicusp ion sources are used in cyclotrons and linear accelerators to produce high beam currents. The structure of a multicusp ion source consists of permanent magnets, filaments, and an anode body. The configuration of the array of permanent magnets, discharge voltage of the plasma, extraction bias voltage, and structure of the multicusp ion source body decide the quality of the beam. The electrons are emitted from the filament by thermionic emission. The emission current can be calculated from thermal information pertaining to the filament, and from the applied voltage and current. The electron trajectories were calculated using CST Particle Studio to optimize the plasma. The array configuration of the permanent magnets decides the magnetic field inside the ion source. The extraction bias voltage and the structure of the multicusp ion source body decide the electric field. Optimization of the electromagnetic field was performed with these factors. CST Particle Studio was used to calculate the electron temperature with a varying permanent magnet array. Four types of permanent magnet array were simulated to optimize the electron temperature. It was found that a 2-layer full line cusp field (with inverse field) produced the best electron temperature control behavior.

Characterization of calcium oxide catalysts from natural sources and their application in the transesterification of sunflower oil.

Science.gov (United States)

Correia, Leandro Marques; Saboya, Rosana Maria Alves; Campelo, Natália de Sousa; Cecilia, Juan Antonio; Rodríguez-Castellón, Enrique; Cavalcante, Célio Loureiro; Vieira, Rodrigo Silveira

2014-01-01

The catalytic activities of calcium oxide obtained from natural sources (crab shell and eggshell) were characterized and evaluated in the transesterification of vegetable oil. These catalysts are mainly composed of calcium carbonate, which is partially converted into CaO after calcination (900°C for 2h). The catalysts have some advantages, such as abundant occurrence, low cost, porous structure, and nontoxic. The materials were characterized by XRD, FTIR, TG/DTG, CO2-TPD, XPS, SEM, and BET methods. The thermal treatment produces small particles of CaCO3 and CaO that are responsible for the catalytic activity. The conversion from triglycerides to methyl ester was not observed in transesterification carried out using natural crab shell and eggshell. Under optimized reaction conditions, the conversions to YFAME using the calcined catalysts were: crab shell (83.10±0.27 wt.%) and eggshell (97.75±0.02 wt.%). These results, showed that these materials have promising viability in transesterification for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Data sources avalaibility to dangers identification

International Nuclear Information System (INIS)

Carrillo, M.

2013-01-01

The power point presentation is about epidemiological studies, animals in vivo studies, in vitro studies, activity and structure, key data to consider for risk characterization, stimation and dose, exposicition limits,NOEL, data sources more important to exposition evaluation, consumption Data, concentration data, population data studies, chemical concentration in food, maximum levels(LMs) maximum limits of wastes LMRs, monitoring data and sanitary surveillance, diet studies, (EDTs), data base GEMS/Food, data report and use, consumption data base, risk determination strategy in health produced by food contaminant intake

Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors

Science.gov (United States)

Nashy, El-Shahat H. A.; Al-Ashkar, Emad; Abdel Moez, A.

2012-02-01

Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows.

Lead isotopic characterization of respirable urban aerosols and related sources, Santiago-Chile

International Nuclear Information System (INIS)

Diaz, M; Kawashita, K; Antinao, J.L

2001-01-01

Santiago de Chile is located in a poorly ventilated valley at 33 o 30' latitude south at an altitude of 550m. Local climate is semi-arid with mean annual rainfall below 350mm. The atmospheric particles constitute one of the main factors of urban air pollution in the city. Morphological characterization of airborne particles of Santiago done by Scanning Electron Microscopy showed the presence of three groups of particles: crystalline. spherical and agglomerate particles. The crystalline shapes originated in geologic sources have perfectly defined crystallographic parameters. The agglomerated shapes are formed by organic material and submicrometrical mineral particles derived from combustion of fossil fuel and the spherical shapes are products of metallurgical activities. Some of them could been associated with the wear of motorcars. Samples of aerosols. sediments and leaded petrol of different distributors were collected. Aerosols were sampled in two sites of Santiago: the Movil monitoring station, at east of the city, and Parque O'Higgins monitoring station in downtown. These two monitoring stations belong to the MACAM network. Sediments of Mapocho, Maipo, San Francisco and Zanjon de la Aguada rivers and two samples from Disputada and Merceditas ores were studied. All the samples have been measured for their 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb ratios. The experimental chemical procedures of sample dissolution and Pb separation by anion exchange chromatography were developed in the Sernageomin clean laboratory of Santiago de Chile. The isotopic measurements were made using a VG-Sector isotope ratio mass spectrometer fitted with a thermal ion source, multi Faraday collector and Daly collector of the Isotopic Geology Laboratory in the Universidade Federal de Rio Grande do Sul, Brazil. The measurements were corrected using NBS 981 and 982 standards. Isotopic results plotted in a 208 Pb/ 204 Pb versus 206 Pb/ 204 Pb diagram and in a 207 Pb/ 204 Pb versus

Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

Science.gov (United States)

Sexton, E. A.; Snelson, C. M.; Chipman, V.; Emer, D. F.; White, R. L.; Emmitt, R.; Wright, A. A.; Drellack, S.; Huckins-Gang, H.; Mercadante, J.; Floyd, M.; McGowin, C.; Cothrun, C.; Bonal, N.

2013-12-01

An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined. For Phase II of the experiment, characterization of the location is required to develop the geologic/geophysical models for the execution of the experiment. Criteria for the location are alluvium thickness of approximately 170 m and a water table below 170 m; minimal fracturing would be ideal. A P-wave mini-vibroseis survey was conducted at a potential site in alluvium to map out the subsurface geology. The seismic reflection profile consisted of 168 geophone stations, spaced 5 m apart. The mini-vibe was a 7,000-lb peak-force source, starting 57.5 m off the north end of the profile and ending 57.5 m past the southern-most geophone. The length of the profile was 835 m. The source points were placed every 5 m, equally spaced between geophones to reduce clipping. The vibroseis sweep was from 20 Hz down to 180 Hz over 8 seconds, and four sweeps were stacked at each shot location. The shot gathers show high signal-to-noise ratios with clear first arrivals across the entire spread and the suggestion of some shallow reflectors. The data were

Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

Energy Technology Data Exchange (ETDEWEB)

Reyes, E.; Sosa, M. A.; Gil V, A. [Universidad de Guanajuato, Division de Ciencias e Ingenierias, Av. Insurgentes 2354, 37150 Leon, Guanajuato (Mexico); Monzon, E., E-mail: eric_1985@fisica.ugto.mx [IMSS, Unidad Medica de Alta Especialidad No. 1, Av. Adolfo Lopez Mateos 1813, 37340 Leon, Guanajuato (Mexico)

2015-10-15

Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

Monte Carlo characterization of the Gamma-Med Hdr plus Ir-192 brachytherapy source

International Nuclear Information System (INIS)

Reyes, E.; Sosa, M. A.; Gil V, A.; Monzon, E.

2015-10-01

Full text: The MCNP4C Monte Carlo code was used to simulate the dosimetry around the Gamma-Med Hdr Plus iridium-192 brachytherapy source in both air/vacuum and water environments. Dosimetry data in water was calculated and are presented into an away-along table. All dosimetric quantities recommended by the AAPM Task Group 43 report have been also calculated. These quantities are air kerma strength, dose rate constant, radial dose function and anisotropy function. The obtained data are compared to this source reference data, finding results in good agreement with them. In this study, recommendations of the AAPM TG-43U1 report have been followed and comply with the most recent AAPM and ESTRO physics committee recommendations about Monte Carlo techniques. The data in the present study complement published data and can be used as input in the Tps or as benchmark data to verify the results of the treatment planning systems as well as a means of comparison with other datasets from this source. (Author)

Emotion impairs extrinsic source memory--An ERP study.

Science.gov (United States)

Mao, Xinrui; You, Yuqi; Li, Wen; Guo, Chunyan

2015-09-01

Substantial advancements in understanding emotional modulation of item memory notwithstanding, controversies remain as to how emotion influences source memory. Using an emotional extrinsic source memory paradigm combined with remember/know judgments and two key event-related potentials (ERPs)-the FN400 (a frontal potential at 300-500 ms related to familiarity) and the LPC (a later parietal potential at 500-700 ms related to recollection), our research investigated the impact of emotion on extrinsic source memory and the underlying processes. We varied a semantic prompt (either "people" or "scene") preceding a study item to manipulate the extrinsic source. Behavioral data indicated a significant effect of emotion on "remember" responses to extrinsic source details, suggesting impaired recollection-based source memory in emotional (both positive and negative) relative to neutral conditions. In parallel, differential FN400 and LPC amplitudes (correctly remembered - incorrectly remembered sources) revealed emotion-related interference, suggesting impaired familiarity and recollection memory of extrinsic sources associated with positive or negative items. These findings thus lend support to the notion of emotion-induced memory trade off: while enhancing memory of central items and intrinsic/integral source details, emotion nevertheless disrupts memory of peripheral contextual details, potentially impairing both familiarity and recollection. Importantly, that positive and negative items result in comparable memory impairment suggests that arousal (vs. affective valence) plays a critical role in modulating dynamic interactions among automatic and elaborate processes involved in memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Sustainability in Open Source Software Commons: Lessons Learned from an Empirical Study of SourceForge Projects

OpenAIRE

Charles M. Schweik

2013-01-01

In this article, we summarize a five-year US National Science Foundation funded study designed to investigate the factors that lead some open source projects to ongoing collaborative success while many others become abandoned. Our primary interest was to conduct a study that was closely representative of the population of open source software projects in the world, rather than focus on the more-often studied, high-profile successful cases. After building a large database of projects (n=174,33...

Advanced Fine Particulate Characterization Methods

Energy Technology Data Exchange (ETDEWEB)

Steven Benson; Lingbu Kong; Alexander Azenkeng; Jason Laumb; Robert Jensen; Edwin Olson; Jill MacKenzie; A.M. Rokanuzzaman

2007-01-31

The characterization and control of emissions from combustion sources are of significant importance in improving local and regional air quality. Such emissions include fine particulate matter, organic carbon compounds, and NO{sub x} and SO{sub 2} gases, along with mercury and other toxic metals. This project involved four activities including Further Development of Analytical Techniques for PM{sub 10} and PM{sub 2.5} Characterization and Source Apportionment and Management, Organic Carbonaceous Particulate and Metal Speciation for Source Apportionment Studies, Quantum Modeling, and High-Potassium Carbon Production with Biomass-Coal Blending. The key accomplishments included the development of improved automated methods to characterize the inorganic and organic components particulate matter. The methods involved the use of scanning electron microscopy and x-ray microanalysis for the inorganic fraction and a combination of extractive methods combined with near-edge x-ray absorption fine structure to characterize the organic fraction. These methods have direction application for source apportionment studies of PM because they provide detailed inorganic analysis along with total organic and elemental carbon (OC/EC) quantification. Quantum modeling using density functional theory (DFT) calculations was used to further elucidate a recently developed mechanistic model for mercury speciation in coal combustion systems and interactions on activated carbon. Reaction energies, enthalpies, free energies and binding energies of Hg species to the prototype molecules were derived from the data obtained in these calculations. Bimolecular rate constants for the various elementary steps in the mechanism have been estimated using the hard-sphere collision theory approximation, and the results seem to indicate that extremely fast kinetics could be involved in these surface reactions. Activated carbon was produced from a blend of lignite coal from the Center Mine in North Dakota and

Sourcing of internal auditing : An empirical study

NARCIS (Netherlands)

Speklé, R.F.; Elten, van H.J.; Kruis, A.

2007-01-01

This paper studies the factors associated with organizations’ internal audit sourcing decisions, building from a previous study by Widener and Selto (henceforth W&S) [Widener, S.K., Selto, F.H., 1999. Management control systems and boundaries of the firm: why do firms outsource internal audit

Guide for disposition of radioactive-material sources

International Nuclear Information System (INIS)

Taylor, J.M.; Selby, J.M.

1983-04-01

This guide has been prepared to assist DOE Energy Technology Centers in disposing of radioactive-material sources. The guide describes the steps and requirements necessary to dispose of unwanted sources. The steps include obtaining approvals, source characterization, source disposition, packaging requirements, and shipment preparation. A flow chart is provided in the guide to assist the user in the necessary sequential steps of source disposition

Revealing source signatures in ambient BTEX concentrations

International Nuclear Information System (INIS)

Zalel, Amir; Yuval; Broday, David M.

2008-01-01

Management of ambient concentrations of Volatile Organic Compounds (VOCs) is essential for maintaining low ozone levels in urban areas where its formation is under a VOC-limited regime. The significant decrease in traffic-induced VOC emissions in many developed countries resulted in relatively comparable shares of traffic and non-traffic VOC emissions in urban airsheds. A key step for urban air quality management is allocating ambient VOC concentrations to their pertinent sources. This study presents an approach that can aid in identifying sources that contribute to observed BTEX concentrations in areas characterized by low BTEX concentrations, where traditional source apportionment techniques are not useful. Analysis of seasonal and diurnal variations of ambient BTEX concentrations from two monitoring stations located in distinct areas reveal the possibility to identify source categories. Specifically, the varying oxidation rates of airborne BTEX compounds are used to allocate contributions of traffic emissions and evaporative sources to observed BTEX concentrations. - BTEX sources are identified from temporal variations of ambient concentration

Chemical characterization and source identification of PM2.5 at multiple sites in the Beijing-Tianjin-Hebei region, China

Science.gov (United States)

Huang, Xiaojuan; Liu, Zirui; Liu, Jingyun; Hu, Bo; Wen, Tianxue; Tang, Guiqian; Zhang, Junke; Wu, Fangkun; Ji, Dongsheng; Wang, Lili; Wang, Yuesi

2017-11-01

The simultaneous observation and analysis of atmospheric fine particles (PM2.5) on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang) and at a regional background site (Xinglong) in the Beijing-Tianjin-Hebei (BTH) region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF) demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2-40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %), whereas coal combustion was also a large source in Tianjin (12.4 %) and Shijiazhuang (15.5 %), with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust) significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC / EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable contributions from secondary

Chemical characterization and source identification of PM2.5 at multiple sites in the Beijing–Tianjin–Hebei region, China

Directory of Open Access Journals (Sweden)

X. Huang

2017-11-01

Full Text Available The simultaneous observation and analysis of atmospheric fine particles (PM2.5 on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang and at a regional background site (Xinglong in the Beijing–Tianjin–Hebei (BTH region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2–40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %, whereas coal combustion was also a large source in Tianjin (12.4 % and Shijiazhuang (15.5 %, with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC ∕ EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable

Obsidian sources characterized by neutron-activation analysis.

Science.gov (United States)

Gordus, A A; Wright, G A; Griffin, J B

1968-07-26

Concentrations of elements such as manganese, scandium, lanthanum, rubidium, samarium, barium, and zirconium in obsidian samples from different flows show ranges of 1000 percent or more, whereas the variation in element content in obsidian samples from a single flow appears to be less than 40 percent. Neutron-activation analysis of these elements, as well as of sodium and iron, provides a means of identifying the geologic source of an archeological artifact of obsidian.

Characterization of a neutron source of 239PuBe

International Nuclear Information System (INIS)

Hernandez V, R.; Chacon R, A.; Hernandez D, V. M.; Mercado, G. A.; Vega C, H. R.; Ramirez G, J.

2009-10-01

The spectrum equivalent dose and environmental equivalent dose f a 239 PuBe source have been determined. The appropriate handling of a neutron source depends on the knowledge of its characteristics, such as its energy distribution, total rate of flowing and dosimetric magnitudes. In many facilities have not spectrometer that allows to determine the spectrum and then area monitors are used that give a dosimetric magnitude starting from measuring the flowing rate and the use of conversion factors, however this procedure has many limitations and it is preferable to measure the spectra and starting from this information the interest dosimetric magnitudes are calculated. In this work a Bonner sphere spectrometer has been used with a 6 LiI(Eu) scintillator obtaining the count rates that produce, to a distance of 100 cm, a 239 PuBe source of 1.85E(11) Bq. The spectrum was reconstructed starting from the count rates using BUNKIUT code and response matrix UTA4. With the spectrum information was calculated the source intensity, total flow, energy average, equivalent dose rate, environmental equivalent dose rate, equivalent dose coefficient and environmental equivalent dose coefficient. By means of two area monitors for neutrons, Eberline ASP-1 and LB 6411 of Berthold the equivalent dose and environmental equivalent dose were measured. The determinate values were compared with those reported in literature and it found that are coincident inside 17%. (Author)

Review of SFR In-Vessel Radiological Source Term Studies

International Nuclear Information System (INIS)

Suk, Soo Dong; Lee, Yong Bum

2008-10-01

An effort has been made in this study to search for and review the literatures in public domain on the studies of the phenomena related to the release of radionuclides and aerosols to the reactor containment of the sodium fast reactor (SFR) plants (i.e., in-vessel source term), made in Japan and Europe including France, Germany and UK over the last few decades. Review work is focused on the experimental programs to investigate the phenomena related to determining the source terms, with a brief review on supporting analytical models and computer programs. In this report, the research programs conducted to investigate the CDA (core disruptive accident) bubble behavior in the sodium pool for determining 'primary' or 'instantaneous' source term are first introduced. The studies performed to determine 'delayed source term' are then described, including the various stages of phenomena and processes: fission product (FP) release from fuel , evaporation release from the surface of the pool, iodine mass transfer from fission gas bubble, FP deposition , and aerosol release from core-concrete interaction. The research programs to investigate the release and transport of FPs and aerosols in the reactor containment (i.e., in-containment source term) are not described in this report

ITER Safety Task NID-5A, Subtask 1-1: Source terms and energies - initial tritium source terms. Final report

International Nuclear Information System (INIS)

Fong, C.; Kalyanam, K.M.; Tanaka, M.R.; Sood, S.; Natalizio, A.; Delisle, M.

1995-02-01

The overall objective of the Early Safety and Environmental Characterization Study (ESECS) is to assess the environmental impact of tritium using appropriate assumptions on a hypothetical site for ITER, having the r eference s ite characteristics as proposed by the JCT. The objective of this work under the above subtask 1-1, NID-5a, is to determine environmental source terms (i.e., process source term x containment release fraction) for the fuel cycle and cooling systems. The work is based on inventories and process source terms (i.e., inventory x mobilization fraction), provided by others (under Task NID 3b). The results of this work form the basis for the determination, by others, of the off-site dose (i.e., environmental source term x dose/release ratio). For the determination of the environmental source terms, the TMAP4 code has been utilized (ref 1). This code is approved by ITER for safety assessment. Volume 2 is a compilation of appendices giving detailed results of the study. 5 figs

Establishment of a Practical Approach for Characterizing the Source of Particulates in Water Distribution Systems

Directory of Open Access Journals (Sweden)

Seon-Ha Chae

2016-02-01

Full Text Available Water quality complaints related to particulate matter and discolored water can be troublesome for water utilities in terms of follow-up investigations and implementation of appropriate actions because particulate matter can enter from a variety of sources; moreover, physicochemical processes can affect the water quality during the purification and transportation processes. The origin of particulates can be attributed to sources such as background organic/inorganic materials from water sources, water treatment plants, water distribution pipelines that have deteriorated, and rehabilitation activities in the water distribution systems. In this study, a practical method is proposed for tracing particulate sources. The method entails collecting information related to hydraulic, water quality, and structural conditions, employing a network flow-path model, and establishing a database of physicochemical properties for tubercles and slimes. The proposed method was implemented within two city water distribution systems that were located in Korea. These applications were conducted to demonstrate the practical applicability of the method for providing solutions to customer complaints. The results of the field studies indicated that the proposed method would be feasible for investigating the sources of particulates and for preparing appropriate action plans for complaints related to particulate matter.

Common characterization of variability and forecast errors of variable energy sources and their mitigation using reserves in power system integration studies

Energy Technology Data Exchange (ETDEWEB)

Menemenlis, N.; Huneault, M. [IREQ, Varennes, QC (Canada); Robitaille, A. [Dir. Plantif. de la Production Eolienne, Montreal, QC (Canada). HQ Production; Holttinen, H. [VTT Technical Research Centre of Finland, VTT (Finland)

2012-07-01

This In this paper we define and characterize the two random variables, variability and forecast error, over which uncertainty in power systems operations is characterized and mitigated. We show that the characterization of both these variables can be carried out with the same mathematical tools. Furthermore, this common characterization of random variables lends itself to a common methodology for the calculation of non-contingency reserves required to mitigate their effects. A parallel comparison of these two variables demonstrates similar inherent statistical properties. They depend on imminent conditions, evolve with time and can be asymmetric. Correlation is an important factor when aggregating individual wind farm characteristics in forming the distribution of the total wind generation for imminent conditions. (orig.)

The Southeastern Aerosol Research and Characterization (SEARCH) study: spatial variations and chemical climatology, 1999-2010.

Science.gov (United States)

Blanchard, C L; Hidy, G M; Tanenbaum, S; Edgerton, E S; Hartsell, B E

2013-03-01

The Southeastern Aerosol Research and Characterization (SEARCH) study, which has been in continuous operation from 1999 to 2012, was implemented to investigate regional and urban air pollution in the southeastern United States. With complementary data from other networks, the SEARCH measurements provide key knowledge about long-term urban/nonurban pollution contrasts and regional climatology affecting inland locations and sites along the Gulf of Mexico coastline. Analytical approaches ranging from comparisons of mean concentrations to the application of air mass trajectories and principal component analysis provide insight into local and area-wide pollution. Gases (carbon monoxide, sulfur dioxide, nitrogen oxides, ozone, and ammonia), fine particle mass concentration, and fine particle species concentrations (including sulfate, elementary carbon, and organic carbon) are affected by a combination of regional conditions and local emission sources. Urban concentrations in excess of regional baselines and intraurban variations of concentrations depend on source proximity, topography, and local meteorological processes. Regional-scale pollution events (95th percentile concentrations) involving more than 6 of the 8 SEARCH sites are rare (< 2% of days), while subregional events affecting 4-6 sites occur on approximately 10% of days. Regional and subregional events are characterized by widely coincident elevated concentrations of ozone, sulfate, and particulate organic carbon, driven by persistent synoptic-scale air mass stagnation and higher temperatures that favor formation of secondary species, mainly in the summer months. The meteorological conditions associated with regional stagnation do not favor long-range transport of polluted air masses during episodes. Regional and subregional pollution events frequently terminate with southward and eastward penetration of frontal systems, which may initially reduce air pollutant concentrations more inland than along the Gulf

Characterization of neutron flux spectra in the irradiation sites of a 37 GBq {sup 241}Am-Be isotopic source

Energy Technology Data Exchange (ETDEWEB)

Yücel, Haluk [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey); Budak, Mustafa Guray, E-mail: mbudak@gazi.edu.tr [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Karadag, Mustafa [Gazi University, Gazi Education Faculty, 06500 Teknikokullar, Ankara (Turkey); Yüksel, Alptuğ Özer [Ankara University, Institute of Nuclear Sciences, 06100 Tandogan, Ankara (Turkey)

2014-11-01

Highlights: • An irradiation unit was installed using a 37 GBq {sup 241}Am-Be neutron source. • The source neutrons moderated by using both water and paraffin. • Irradiation unit was shielded by boron oxide and lead against neutrons and gammas. • There are two sites for irradiations, one of them has a pneumatic transfer system. • Cadmium ratio method was used for irradiation site characterization. - Abstract: For the applicability of instrumental neutron activation analysis (NAA) technique, an irradiation unit with a 37 GBq {sup 241}Am-Be neutron source was installed at Institute of Nuclear Sciences of Ankara University. Design and configuration properties of the irradiation unit are described. It has two different sample irradiation positions, one is called site #1 having a pneumatic sample transfer system and the other is site #2 having a location for manual use. In order to characterize neutron flux spectra in the irradiation sites, the measurement results were obtained for thermal (φ{sub th}) and epithermal neutron fluxes (φ{sub epi}), thermal to epithermal flux ratio (f) and epithermal spectrum shaping factors (α) by employing cadmium ratios of gold (Au) and molybdenum (Mo) monitors. The activities produced in these foils were measured by using a p-type, 44.8% relative efficiency HPGe well detector. For the measured γ-rays, self-absorption and true coincidence summing effects were taken into account. Additionally, thermal neutron self-shielding and resonance neutron self-shielding effects were taken into account in the measured results. For characterization of site #1, the required parameters were found to be φ{sub th} = (2.11 ± 0.05) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (3.32 ± 0.17) × 10{sup 1} n cm{sup −2} s{sup −1}, f = 63.6 ± 1.5, α = 0.045 ± 0.009, respectively. Similarly, those parameters were measured in site #2 as φ{sub th} = (1.49 ± 0.04) × 10{sup 3} n cm{sup −2} s{sup −1}, φ{sub epi} = (2.93 ± 0

Preliminary study on biosynthesis and characterization of bacteria cellulose films from coconut water

Science.gov (United States)

Indrianingsih, A. W.; Rosyida, V. T.; Jatmiko, T. H.; Prasetyo, D. J.; Poeloengasih, C. D.; Apriyana, W.; Nisa, K.; Nurhayati, S.; Hernawan; Darsih, C.; Pratiwi, D.; Suwanto, A.; Ratih, D.

2017-12-01

Bacterial cellulose produced by Acetobacter xylinum is a unique type of bacterial cellulose. It contains more than 90% of water. A preliminary study had shown that bacterial cellulose films has remarkable mechanical properties. The aim of this study was to investigate the optimum condition such as percentage of carbon source, time of cultivation, and pH to produce bacterial cellulose films from local coconut water, and its characterization on morphology, swelling ability and tensile strength of dried bacterial cellulose. A. xylinum was grown on coconut water culture medium with addition of 3%, 5%, and 7% of sugar, while the cultivation time was vary from 3 days, 5 days and 7 days. pH condition was conducted in pH 3, pH 5 and pH 7. Bacterial cellulose samples were dried using oven with temperature of 100°C until the moisture content reached 4-5%. This study showed that several parameters for optimum condition to produce bacterial cellulose films from local waste of coconut water had been obtained (5% of carbon source; pH 5; and 7 day of incubation period). The electron microscopy also showed that dried bacterial cellulose films had pores covered by fibrils on the surface. Therefore, the present work proposes the optimum formula and condition that can be used based on properties of end product needed.

A comparative study of SPME GC-MS vs SPME-MS approaches for characterization of honey source

OpenAIRE

García-Sarrió, María Jesús; Sanz, María Luz; Sanz Perucha, Jesús; Soria, Ana C.

2015-01-01

Honey is greatly appreciated by consumers not only for its nutritive properties and sweet taste, but also for its pleasant aroma. Different unifloral, multifloral and honeydew honeys are marketed nowadays, and their characterization for authentication purposes or to increase their added value represents a challenge for the analyst. Honey aroma is dependent on its volatile composition, which in turn is influenced by the nectar or honeydew collected by bees as well as by beekeeping ...

Characterization of ionizing radiation effects in MOS structures by study of bipolar operation; Caracterisation des effets induits par irradiations ionisantes dans des structures MOS a partir de leur fonctionnement en regime bipolaire

Energy Technology Data Exchange (ETDEWEB)

Bakhtiar, H. [Univ. Teknologi Malaysia, Dept. of Physics, Johor (Malaysia); Picard, C.; Brisset, C. [CEA Saclay, Lab. d' Electronique et de Technologie de l' Informatique, LETI, 91 - Gif-sur-Yvette (France); Bakhtiar, H.; Hoffmann, A.; Charles, J.P. [Metz Univ., LICM-CLOES-Supelec, 57 (France)

1999-07-01

This work presents an original method to characterize radiation effects of micronic transistors. The characterization includes a study of the transistor substrate-drain junction and current gain variation of the bipolar transistor (drain-substrate-source as emitter-base-collector) for different gate voltages. (author000.

Characterization of Leucaena (Leucaena leucephala) oil by direct analysis in real time (DART) ion source and gas chromatography

International Nuclear Information System (INIS)

Alam, M.; Alandis, N.M.; Sharmin, E.; Ahmad, N.; Alrayes, B.F.; Ali, D.

2017-01-01

For the first time, we report the characterization of triacylglycerols and fatty acids in Leucaena (Leucaena leucephala) oil [LUCO], an unexplored nontraditional non-medicinal plant belonging to the family Fabaceae. LUCO was converted to fatty acid methyl esters (FAMEs). We analyzed the triacylglycerols (TAGs) of pure LUCO and their FAMEs by time-of-flight mass spectrometry (TOF-MS) followed by multivariate analysis for discrimination among the FAMEs. Our investigations for the analysis of LUCO samples represent noble features of glycerides. A new type of ion source, coupled with high-resolution TOF-MS was applied for the comprehensive analysis of triacylglycerols. The composition of fatty acid based LUCO oil was studied using Gas Chromatography (GC-FID). The major fatty acid components of LUCO oil are linoleic acid (52.08%) oleic acid (21.26%), palmitic acid (7.91%) and stearic acid (6.01%). A metal analysis in LUCO was done by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The structural elucidation and thermal stability of LUCO were studied by FT-IR, 1H NMR, 13C NMR spectroscopic techniques and TGA-DSC, respectively. We also measured the cytotoxicity of LUCO [es

Novel plasma source for safe beryllium spectral line studies in the presence of beryllium dust

Science.gov (United States)

Stankov, B. D.; Vinić, M.; Gavrilović Božović, M. R.; Ivković, M.

2018-05-01

Plasma source for beryllium spectral line studies in the presence of beryllium dust particles was realised. The guideline during construction was to prevent exposure to formed dust, considering the toxicity of beryllium. Plasma source characterization through determination of optimal working conditions is described. The necessary conditions for Be spectral line appearance and optimal conditions for line shape measurements are found. It is proven experimentally that under these conditions dust appears coincidently with the second current maximum. The electron density measured after discharge current maximum is determined from the peak separation of the hydrogen Balmer beta spectral line, and the electron temperature is determined from the ratios of the relative intensities of Be spectral lines emitted from successive ionized stages of atoms. Maximum values of electron density and temperature are measured to be 9.3 × 1022 m-3 and 16 800 K, respectively. Construction details and testing of the BeO discharge tube in comparison with SiO2 and Al2O3 discharge tubes are also presented in this paper.

Phenotypic characterization, genetic mapping and candidate gene analysis of a source conferring reduced plant height in sunflower.

Science.gov (United States)

Ramos, María Laura; Altieri, Emiliano; Bulos, Mariano; Sala, Carlos A

2013-01-01

Reduced height germplasm has the potential to increase stem strength, standability, and also yields potential of the sunflower crop (Helianthus annuus L. var. macrocarpus Ckll.). In this study, we report on the inheritance, mapping, phenotypic and molecular characterization of a reduced plant height trait in inbred lines derived from the source DDR. This trait is controlled by a semidominant allele, Rht1, which maps on linkage group 12 of the sunflower public consensus map. Phenotypic effects of this allele include shorter height and internode length, insensibility to exogenous gibberellin application, normal skotomorphogenetic response, and reduced seed set under self-pollination conditions. This later effect presumably is related to the reduced pollen viability observed in all DDR-derived lines studied. Rht1 completely cosegregated with a haplotype of the HaDella1 gene sequence. This haplotype consists of a point mutation converting a leucine residue in a proline within the conserved DELLA domain. Taken together, the phenotypic, genetic, and molecular results reported here indicate that Rht1 in sunflower likely encodes an altered DELLA protein. If the DELPA motif of the HaDELLA1 sequence in the Rht1-encoded protein determines by itself the observed reduction in height is a matter that remains to be investigated.

Characterization of a Common-Source Amplifier Using Ferroelectric Transistors

Science.gov (United States)

Hunt, Mitchell; Sayyah, Rana; MacLeond, Todd C.; Ho, Pat D.

2010-01-01

This paper presents empirical data that was collected through experiments using a FeFET in the established common-source amplifier circuit. The unique behavior of the FeFET lends itself to interesting and useful operation in this widely used common-source amplifier. The paper examines the effect of using a ferroelectric transistor for the amplifier. It also examines the effects of varying load resistance, biasing, and input voltages on the output signal and gives several examples of the output of the amplifier for a given input. The difference between a commonsource amplifier using a ferroelectric transistor and that using a MOSFET is addressed.

Characterization and source identification of organic matter in view of land uses and heavy rainfall in the Lake Shihwa, Korea

International Nuclear Information System (INIS)

Lee, Yeonjung; Hur, Jin; Shin, Kyung-Hoon

2014-01-01

Highlights: • Organic matter derived from industrial area showed high biodegradability. • Organic matter transported from rural area was of refractory nature. • Autochthonous organic matter dominated in lake during the dry season. • Contributions of organic source by industrial and rural area increased at rainy season. - Abstract: The characteristics and sources of organic matter in water of the Lake Shihwa, which receives inputs from rural, urban, and industrial areas, were evaluated by examining the biodegradable organic carbon concentration, fluorescence spectra, and carbon and nitrogen isotope ratios, especially during rainy season and dry season. The organic matter transported from rural areas was of refractory nature, while that of industrial origin decomposed rapidly. As compared to the dry season, the organic matter in the rainy season was characterized by a reduced labile fraction. During the dry season, the autochthonous organic matter dominated in the lake, however, the contributions of allochthonous organic sources by industrial and rural areas significantly increased at rainy season. This investigation revealed that the transport of organic matter of anthropogenic origin to the Lake Shihwa was mainly influenced by heavy rainfall. Moreover, each anthropogenic source could differently influence the occurrence of organic matter in water of the Lake Shihwa

Experimental Component Characterization, Monte-Carlo-Based Image Generation and Source Reconstruction for the Neutron Imaging System of the National Ignition Facility

Energy Technology Data Exchange (ETDEWEB)

Barrera, C A; Moran, M J

2007-08-21

The Neutron Imaging System (NIS) is one of seven ignition target diagnostics under development for the National Ignition Facility. The NIS is required to record hot-spot (13-15 MeV) and downscattered (6-10 MeV) images with a resolution of 10 microns and a signal-to-noise ratio (SNR) of 10 at the 20% contour. The NIS is a valuable diagnostic since the downscattered neutrons reveal the spatial distribution of the cold fuel during an ignition attempt, providing important information in the case of a failed implosion. The present study explores the parameter space of several line-of-sight (LOS) configurations that could serve as the basis for the final design. Six commercially available organic scintillators were experimentally characterized for their light emission decay profile and neutron sensitivity. The samples showed a long lived decay component that makes direct recording of a downscattered image impossible. The two best candidates for the NIS detector material are: EJ232 (BC422) plastic fibers or capillaries filled with EJ399B. A Monte Carlo-based end-to-end model of the NIS was developed to study the imaging capabilities of several LOS configurations and verify that the recovered sources meet the design requirements. The model includes accurate neutron source distributions, aperture geometries (square pinhole, triangular wedge, mini-penumbral, annular and penumbral), their point spread functions, and a pixelated scintillator detector. The modeling results show that a useful downscattered image can be obtained by recording the primary peak and the downscattered images, and then subtracting a decayed version of the former from the latter. The difference images need to be deconvolved in order to obtain accurate source distributions. The images are processed using a frequency-space modified-regularization algorithm and low-pass filtering. The resolution and SNR of these sources are quantified by using two surrogate sources. The simulations show that all LOS

Chandra Source Catalog: Background Determination and Source Detection

Science.gov (United States)

McCollough, Michael L.; Rots, A. H.; Primini, F. A.; Evans, I. N.; Glotfelty, K. J.; Hain, R.; Anderson, C. S.; Bonaventura, N. R.; Chen, J. C.; Davis, J. E.; Doe, S. M.; Evans, J. D.; Fabbiano, G.; Galle, E.; Gibbs, D. G.; Grier, J. D.; Hall, D. M.; Harbo, P. N.; He, X.; Houck, J. C.; Karovska, M.; Lauer, J.; McDowell, J. C.; Miller, J. B.; Mitschang, A. W.; Morgan, D. L.; Nichols, J. S.; Nowak, M. A.; Plummer, D. A.; Refsdal, B. L.; Siemiginowska, A. L.; Sundheim, B. A.; Tibbetts, M. S.; Van Stone, D. W.; Winkelman, S. L.; Zografou, P.

2009-01-01

The Chandra Source Catalog (CSC) is a major project in which all of the pointed imaging observations taken by the Chandra X-Ray Observatory will used to generate the most extensive X-ray source catalog produced to date. Early in the development of the CSC it was recognized that the ability to estimate local background levels in an automated fashion would be critical for essential CSC tasks such as source detection, photometry, sensitivity estimates, and source characterization. We present a discussion of how such background maps are created directly from the Chandra data and how they are used in source detection. The general background for Chandra observations is rather smoothly varying, containing only low spatial frequency components. However, in the case of ACIS data, a high spatial frequency component is added that is due to the readout streaks of the CCD chips. We discuss how these components can be estimated reliably using the Chandra data and what limitations and caveats should be considered in their use. We will discuss the source detection algorithm used for the CSC and the effects of the background images on the detection results. We will also touch on some the Catalog Inclusion and Quality Assurance criteria applied to the source detection results. This work is supported by NASA contract NAS8-03060 (CXC).

Lessons Learned from Characterization, Performance Assessment, and EPA Regulatory Review of the 1996 Actinide Source Term for the Waste Isolation Pilot Plant

International Nuclear Information System (INIS)

Larson, K.W.; Moore, R.C.; Nowak, E.J.; Papenguth, H.W.; Jow, H.

1999-01-01

The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) facility for the permanent disposal of transuranic waste from defense activities. In 1996, the DOE submitted the Title 40 CFR Part 191 Compliance Certification Application for the Waste Isolation Pilot Plant (CCA) to the US Environmental Protection Agency (EPA). The CCA included a probabilistic performance assessment (PA) conducted by Sandia National Laboratories to establish compliance with the quantitative release limits defined in 40 CFR 191.13. An experimental program to collect data relevant to the actinide source term began around 1989, which eventually supported the 1996 CCA PA actinide source term model. The actinide source term provided an estimate of mobile dissolved and colloidal Pu, Am, U, Th, and Np concentrations in their stable oxidation states, and accounted for effects of uncertainty in the chemistry of brines in waste disposal areas. The experimental program and the actinide source term included in the CCA PA underwent EPA review lasting more than 1 year. Experiments were initially conducted to develop data relevant to the wide range of potential future conditions in waste disposal areas. Interim, preliminary performance assessments and actinide source term models provided insight allowing refinement of experiments and models. Expert peer review provided additional feedback and confidence in the evolving experimental program. By 1995, the chemical database and PA predictions of WIPP performance were considered reliable enough to support the decision to add an MgO backfill to waste rooms to control chemical conditions and reduce uncertainty in actinide concentrations, especially for Pu and Am. Important lessons learned through the characterization, PA modeling, and regulatory review of the actinide source term are (1) experimental characterization and PA should evolve together, with neither activity completely dominating the other, (2) the understanding of physical processes

Simulation study on ion extraction from ECR ion sources

International Nuclear Information System (INIS)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author)

Simulation study on ion extraction from ECR ion sources

Energy Technology Data Exchange (ETDEWEB)

Fu, S.; Kitagawa, A.; Yamada, S.

1993-07-01

In order to study beam optics of NIRS-ECR ion source used in HIMAC, EGUN code has been modified to make it capable of modeling ion extraction from a plasma. Two versions of the modified code are worked out with two different methods in which 1-D and 2-D sheath theories are used respectively. Convergence problem of the strong nonlinear self-consistent equations is investigated. Simulations on NIRS-ECR ion source and HYPER-ECR ion source (in INS, Univ. of Tokyo) are presented in this paper, exhibiting an agreement with the experimental results. Some preliminary suggestions on the upgrading the extraction systems of these sources are also proposed. (author).

Measuring the fractal dimension of the seismic source through the high-frequency fall-off of source spectra

International Nuclear Information System (INIS)

Wu, Z.L.; Chen, Y.T.; Kim, S.G.

1995-09-01

Using the Wigner-distribution estimation, the high-frequency fall-off of source spectra was estimated. The technique was applied to the analysis of the source spectra of the July 22, 1994, Vladivostok M6.4 deep-focus earthquake and that of the July 22, 1994, Northern Japan Sea M5.7 deep-focus earthquake. It is shown that the high-frequency fall-off of the source spectra of these two earthquakes may be characterized by two parts. Between the first corner frequency f 1 and the second corner frequency f 2 , the high-frequency fall-off of the source spectra can be represented by f 5.0 : above f 2 , the high-frequency fall-off can be represented by f 1.4 . In the perspective of the fractal geometry of earthquake source, it seems that the deep-focus earthquakes under consideration may be characterized as being composed of some 'sub events'. On the other hand, each sub event has its complex structure. (author). 12 refs, 3 figs, 1 tab

Overview of receptor-based source apportionment studies for speciated atmospheric mercury

OpenAIRE

Cheng, I.; Xu, X.; Zhang, L.

2015-01-01

Receptor-based source apportionment studies of speciated atmospheric mercury are not only concerned with source contributions but also with the influence of transport, transformation, and deposition processes on speciated atmospheric mercury concentrations at receptor locations. Previous studies applied multivariate receptor models including principal components analysis and positive matrix factorization, and back trajectory receptor models including potential source contri...

Alkali deuteride negative ion source development plan

International Nuclear Information System (INIS)

Anon.

1977-01-01

A three phase program is described for the development of neutral beam systems. In the first phase, concluded in May, 1977, the laser initiated source was characterized. In phase two, scheduled for completion in September, 1978, negative ion confinement and extraction are investigated using laser energy deposition as a baseline method to produce D - . In addition other energy deposition schemes are studied in order to define a baseline energetic beam source system. The third phase is devoted to producing an integrated baseline system and scaling it up in current and energy to meet magnetic confinement system requirements

Optical and spectroscopic studies on tannery wastes as a possible source of organic semiconductors.

Science.gov (United States)

Nashy, El-Shahat H A; Al-Ashkar, Emad; Moez, A Abdel

2012-02-01

Tanning industry produces a large quantity of solid wastes which contain hide proteins in the form of protein shavings containing chromium salts. The chromium wastes are the main concern from an environmental stand point of view, because chrome wastes posses a significant disposal problem. The present work is devoted to investigate the possibility of utilizing these wastes as a source of organic semi-conductors as an alternative method instead of the conventional ones. The chemical characterization of these wastes was determined. In addition, the Horizontal Attenuated Total Reflection (HATR) FT-IR spectroscopic analysis and optical parameters were also carried out for chromated samples. The study showed that the chromated samples had suitable absorbance and transmittance in the wavelength range (500-850 nm). Presence of chromium salt in the collagen samples increases the absorbance which improves the optical properties of the studied samples and leads to decrease the optical energy gap. The obtained optical energy gap gives an impression that the environmentally hazardous chrome shavings wastes can be utilized as a possible source of natural organic semiconductors with direct and indirect energy gap. This work opens the door to use some hazardous wastes in the manufacture of electronic devices such as IR-detectors, solar cells and also as solar cell windows. Copyright © 2011 Elsevier B.V. All rights reserved.

Source apportionment of indoor, outdoor and personal PM2.5 exposure of pregnant women in Barcelona, Spain

Science.gov (United States)

Minguillón, M. C.; Schembari, A.; Triguero-Mas, M.; de Nazelle, A.; Dadvand, P.; Figueras, F.; Salvado, J. A.; Grimalt, J. O.; Nieuwenhuijsen, M.; Querol, X.

2012-11-01

Exposure to air pollution has been shown to adversely affect foetal development in the case of pregnant women. The present study aims to investigate the PM composition and sources influencing personal exposure of pregnant women in Barcelona. To this end, indoor, outdoor and personal exposure measurements were carried out for a selection of 54 pregnant women between November 2008 and November 2009. PM2.5 samples were collected during two consecutive days and then analysed for black smoke (BS), major and trace elements, and polycyclic aromatic hydrocarbons (PAHs) concentrations. Personal information such as commuting patterns and cosmetics use was also collected. PM2.5 concentrations were higher for personal samples than for indoor and outdoor environments. Indoor, outdoor and personal BS and sulphate concentrations were strongly correlated, although some specific indoor and outdoor sulphate sources may exist. Average trace elements concentrations were similar indoor, outdoor and for personal exposure, but the correlations were moderate for most of them. Most of the PAHs concentrations showed strong correlations indoor-outdoor. A source apportionment analysis of the PM composition data by means of a Positive Matrix Factorization (PMF) resulted in the identification of six sources for the outdoor and indoor environments: secondary sulphate, fueloil + sea salt (characterized by V, Ni, Na and Mg), mineral, cigarette (characterized by K, Ce, Cd, benzo(k)fluoranthene and benzo(ghi)perylene), road traffic (characterized by BS and low weight PAHs), and industrial (characterized by Pb, Sn, Cu, Mn and Fe). For personal exposure two specific sources were found: cosmetics (characterized by abundance of Ca, Li, Ti and Sr and the absence of Al) and train/subway (characterized by Fe, Mn, Cu and Ba). The contribution of the sources varied widely among women, especially for cigarette (from zero to up to 4 μg m-3), train/subway (up to more than 6 μg m-3) and cosmetics (up to more

Site characterization studies in the NWTS program

International Nuclear Information System (INIS)

Shipler, D.; Evans, G.

1980-01-01

The US Department of Energy (DOE) has the responsibility to identify sites and construct and operate facilities for the storage or isolation of spent fuel and/or reprocessing radioactive wastes from commercial nuclear power plants. The National Waste Terminal Storage (NWTS) Program has been initiated by the DOE to develop the technology and demonstrate the feasibility of burial and isolation of high level radioactive waste in deep geologic formations. The NTWS Program plan which sets forth the criteria, procedures, and other considerations required to characterize and select a site in a comprehensive stepwise manner is discussed. The plan is not specific to any given geologic medium but serves as a guide for site selection in any geohydrologic system deemed appropriate for consideration for a deep geologic repository. The plan will be used by all NWTS Project Offices in the conduct of their site characterization program. The plan will be updated, as warranted, to reflect technology development, National policies, rulemakings by regulatory agencies, and other changing political, social, and institutional considerations. Site characterization begins with the identification of regions believed to have suitable geologic, hydrologic, and environmental characteristics for repository siting. This is followed by an iterative process of data collection and analysis to identify areas and locations which appear most suitable for further investigations. In addition, screening studies of the DOE's nuclear complexes has led to the selection of the Nevada Test Site and the Hanford Site for further characterization studies. The site characterization process results in a number of candidate sites from which a site will be selected and proposed to the NRC for licensing

Extraction and characterization of anthocyanin colorants from plant sources

Directory of Open Access Journals (Sweden)

S. Dyankova

2016-03-01

Full Text Available Abstract. Natural pigments (and especially those of anthocyanins are a valuable source of bioactive compounds and may be used in the production of new functional food ingredients. Furthermore, their applications in the treatment and prevention of chronic disorders are becoming more and more widespread. In the last few years consumers have focused their attention on the natural biologically active compounds as functional food ingredients, and therefore, it may be assumed that natural colorants are an alternative source of synthetic additives. The aim of the study was to determine the quantitative content of monomeric anthocyanin pigments in extracts obtained from eight plants. The total content of monomeric anthocyanin pigments was measured by a pH-differential method. The TLC analysis of the pigment extracts from the different plants showed intensive rose, red and violet stripes corresponding to the anthocyanin content. The extracts from chicory and lavender petals were unstable and their color decreased in intensity in 1 month. The analysis of the experimental data shows that the yield of pigment substances depends on a few factors: the type of plant, the preliminary treatment of the plant and the solvent that is used. The largest quantity of extracted substances in the studied plants were isolated from chokeberry (2 195.9 cyd eq mg/l, followed by blackberry (1 466.2 and one variety of the grapes (1 199.3 . In the case of chokeberry, the pigment content included a large number of anthocyanins and the combination of these components was the reason for the deep red/violet color of the extract. Fresh or frozen materials are the most suitable for extraction of anthocyanin pigments. On the whole, fruit pulp yielded a larger quantity of pigments than juice. Anthocyanins are water-soluble compounds and for that reason their isolation requires water and other polar solvents. Better stabilization of color is obtained by a slight acidification of the

Experimental studies of 2.45 GHz ECR ion sources for the production of high intensity currents

International Nuclear Information System (INIS)

Coly, A.

2010-12-01

This thesis is the result of a collaboration between the Pantechnik company and the LPSC (Laboratory of subatomic physics and cosmology of Grenoble). It consisted in the development of a new test bench dedicated to the characterization of a 2.45 GHz ECR ion sources with the aim of the production of high currents beams for industrial purposes. Two ECR ions sources with different magnetic structures have been tested around the same RF injection system. A new 2.45 GHz ECRIS, named SPEED, featuring a dipolar magnetic field at the extraction has been designed and tested. A study of the beam extraction in the dipolar magnetic field is proposed. First tests have shown a total ionic current density of about 10 mA/cm 2 with a 900 W RF power. Tests with hydrogen plasma have shown a maximum of current on the H 2 + species. Recommendations are given to modify the magnetic structure to improve the H + production yield. The MONO1000 ion source has been tested at high RF power with a wave guide type injection system. Intense total ionic current densities have been measured up to about 95 mA/cm 2 with a diode extraction system. First results using an improved 5 electrode extraction system are presented. (author)

Chemical characterization and source apportionment of submicron aerosols measured in Senegal during the 2015 SHADOW campaign

Science.gov (United States)

Rivellini, Laura-Hélèna; Chiapello, Isabelle; Tison, Emmanuel; Fourmentin, Marc; Féron, Anaïs; Diallo, Aboubacry; N'Diaye, Thierno; Goloub, Philippe; Canonaco, Francesco; Prévôt, André Stephan Henry; Riffault, Véronique

2017-09-01

The present study offers the first chemical characterization of the submicron (PM1) fraction in western Africa at a high time resolution, thanks to collocated measurements of nonrefractory (NR) species with an Aerosol Chemical Speciation Monitor (ACSM), black carbon and iron concentrations derived from absorption coefficient measurements with a 7-wavelength Aethalometer, and total PM1 determined by a TEOM-FDMS (tapered element oscillating microbalance-filtered dynamic measurement system) for mass closure. The field campaign was carried out over 3 months (March to June 2015) as part of the SHADOW (SaHAran Dust Over West Africa) project at a coastal site located in the outskirts of the city of Mbour, Senegal. With an averaged mass concentration of 5.4 µg m-3, levels of NR PM1 in Mbour were 3 to 10 times lower than those generally measured in urban and suburban polluted environments. Nonetheless the first half of the observation period was marked by intense but short pollution events (NR PM1 concentrations higher than 15 µg m-3), sea breeze phenomena and Saharan desert dust outbreaks (PM10 up to 900 µg m-3). During the second half of the campaign, the sampling site was mainly under the influence of marine air masses. The air masses on days under continental and sea breeze influences were dominated by organics (36-40 %), whereas sulfate particles were predominant (40 %) for days under oceanic influence. Overall, measurements showed that about three-quarters of the total PM1 were explained by NR PM1, BC (black carbon) and Fe (a proxy for dust) concentrations, leaving approximately one-quarter for other refractory species. A mean value of 4.6 % for the Fe / PM1 ratio was obtained. Source apportionment of the organic fraction, using positive matrix factorization (PMF), highlighted the impact of local combustion sources, such as traffic and residential activities, which contribute on average to 52 % of the total organic fraction. A new organic aerosol (OA) source

ITER Safety Task NID-5A, Subtask 1-1: Source terms and energies - initial tritium source terms. Final report

International Nuclear Information System (INIS)

Fong, C.; Kalyanam, K.M.; Tanaka, M.R.; Sood, S.; Natalizio, A.; Delisle, M.

1995-02-01

The overall objective of the Early Safety and Environmental Characterization Study (ESECS) is to assess the environmental impact of tritium using appropriate assumptions on a hypothetical site for ITER, having the r eference s ite characteristics as proposed by the JCT. The objective of this work under the above subtask 1-1, NID-5a, is to determine environmental source terms (i.e., process source term x containment release fraction) for the fuel cycle and cooling systems. The work is based on inventories and process source terms (i.e., inventory x mobilization fraction), provided by others (under Task NID 3b). The results of this work form the basis for the determination, by others, of the off-site dose (i.e., environmental source term x dose/release ratio). For the determination of the environmental source terms, the TMAP4 code has been utilized (ref 1). This code is approved by ITER for safety assessment. 6 refs

A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model.

Science.gov (United States)

Hiatt, Jessica R; Davis, Stephen D; Rivard, Mark J

2015-06-01

The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10(10) histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an (125)I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose function ratio between the current

Study of the influence of the silica source on the synthesis of the zeolite precursor MCM-22

International Nuclear Information System (INIS)

Barbosa, A.S.; Santos, E.R.F. dos; Leite, R.C.N.; Rodrigues, M.G.F.

2012-01-01

Zeolite MCM-22 precursors were synthesized under hydrothermal conditions in systems with hexamethyleneimine HMI as bulking agent (driver). Synthesis parameter, such as sources of silica (aerosil® and quartz) was modified to investigate the effects on the morphology and crystallization in precursor MCM-22 zeolite. The products were characterized by X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDX) and Scanning Electron Microscopy (SEM). According to, the X-ray diffraction showed the same characteristic peaks of zeolite MCM-22. It was found that the parameter in this work of synthesis, silica source, affects the hydrothermal synthesis of zeolite MCM-22 precursor. This can be evidenced by the different morphologies found using the different sources of silica. (author)

Feasibility study on X-ray source with pinhole imaging method

International Nuclear Information System (INIS)

Qiu Rui; Li Junli

2007-01-01

In order to verify the feasibility of study on X-ray source with pinhole imaging method, and optimize the design of X-ray pinhole imaging system, an X-ray pinhole imaging equipment was set up. The change of image due to the change of the position and intensity of X-ray source was estimated with mathematical method and validated with experiment. The results show that the change of the spot position and gray of the spot is linearly related with the change of the position and intensity of X-ray source, so it is feasible to study X-ray source with pinhole imaging method in this application. The results provide some references for the design of X-ray pinhole imaging system. (authors)

Characterization and source identification of pollutants in runoff from a mixed land use watershed using ordination analyses.

Science.gov (United States)

Lee, Dong Hoon; Kim, Jin Hwi; Mendoza, Joseph A; Lee, Chang Hee; Kang, Joo-Hyon

2016-05-01

While identification of critical pollutant sources is the key initial step for cost-effective runoff management, it is challenging due to the highly uncertain nature of runoff pollution, especially during a storm event. To identify critical sources and their quantitative contributions to runoff pollution (especially focusing on phosphorous), two ordination methods were used in this study: principal component analysis (PCA) and positive matrix factorization (PMF). For the ordination analyses, we used runoff quality data for 14 storm events, including data for phosphorus, 11 heavy metal species, and eight ionic species measured at the outlets of subcatchments with different land use compositions in a mixed land use watershed. Five factors as sources of runoff pollutants were identified by PCA: agrochemicals, groundwater, native soils, domestic sewage, and urban sources (building materials and automotive activities). PMF identified similar factors to those identified by PCA, with more detailed source mechanisms for groundwater (i.e., nitrate leaching and cation exchange) and urban sources (vehicle components/motor oils/building materials and vehicle exhausts), confirming the sources identified by PCA. PMF was further used to quantify contributions of the identified sources to the water quality. Based on the results, agrochemicals and automotive activities were the two dominant and ubiquitous phosphorus sources (39-61 and 16-47 %, respectively) in the study area, regardless of land use types.

Characterization of the seismic environment at the Sanford Underground Laboratory, South Dakota

Energy Technology Data Exchange (ETDEWEB)

Harms, J; Dorsher, S; Kandhasamy, S; Mandic, V [University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Acernese, F; Barone, F [Universita degli Studi di Salerno, Fisciano (Saudi Arabia) (Italy); Bartos, I; Marka, S [Columbia University, New York, NY 10027 (United States); Beker, M; Van den Brand, J F J; Rabeling, D S [Nikhef, National Institute for Subatomic Physics, Science Park 105, 1098 XG Amsterdam (Netherlands); Christensen, N; Coughlin, M [Carleton College, Northfield, MN 55057 (United States); DeSalvo, R [California Institute of Technology, Pasadena, CA 91125 (United States); Heise, J; Trancynger, T [Sanford Underground Laboratory, 630 East Summit Street, Lead, SD 57754 (United States); Mueller, G [University of Florida, Gainesville, FL 32611 (United States); Naticchioni, L [Department of Physics, University of Rome ' Sapienza' , P.le Aldo Moro 2, 00185 Rome (Italy); O' Keefe, T [Saint Louis University, 3450 Lindell Blvd., St. Louis, MO 63103 (United States); Sajeva, A, E-mail: janosch@caltech.ed [Dipartimento di Fisica ' Enrico Fermi' , Universita di Pisa, Largo Bruno Pontecorvo, Pisa (Italy)

2010-11-21

An array of seismometers is being developed at the Sanford Underground Laboratory, the former Homestake mine, in South Dakota to study the properties of underground seismic fields and Newtonian noise, and to investigate the possible advantages of constructing a third-generation gravitational-wave detector underground. Seismic data were analyzed to characterize seismic noise and disturbances. External databases were used to identify sources of seismic waves: ocean-wave data to identify sources of oceanic microseisms and surface wind-speed data to investigate correlations with seismic motion as a function of depth. In addition, sources of events contributing to the spectrum at higher frequencies are characterized by studying the variation of event rates over the course of a day. Long-term observations of spectral variations provide further insight into the nature of seismic sources. Seismic spectra at three different depths are compared, establishing the 4100 ft level as a world-class low seismic-noise environment.

Characterization of Black and Brown Carbon Concentrations and Sources during winter in Beijing

Science.gov (United States)

Yan, Caiqing; Liu, Yue; Hansen, Anthony D. A.; Močnik, Griša; Zheng, Mei

2017-04-01

Carbonaceous aerosols, including black carbon (BC) and organic carbon (OC), play important roles in air quality, human health, and climate change. A better understanding of sources of light-absorbing carbonaceous aerosol (including black carbon and brown carbon) is particular critical for formulating emission-based control strategies and reducing uncertainties in current aerosol radiative forcing estimates. Beijing, the capital of China, has experienced serious air pollution problems and high concentrations of carbonaceous aerosols in recent years, especially during heating seasons. During November and December of 2016, several severe haze episodes occurred in Beijing, with hourly average PM2.5 mass concentration up to 400 μg/m3. In this study, concentration levels and sources of black carbon and brown carbon were investigated based on 7-wavelength Aethalometer (AE-33) with combination of other PM2.5 chemical composition information. Contributions of traffic and non-traffic emissions (e.g., coal combustion, biomass burning) were apportioned, and brown carbon was separated from black carbon. Our preliminary results showed that (1) Concentrations of BC were around 5.3±4.2 μg/m3 during the study period, with distinct diurnal variations during haze and non-haze days. (2) Traffic emissions contributed to about 37±17% of total BC, and exhibited higher contributions during non-haze days compared to haze days. (3) Coal combustion was a major source of black carbon and brown carbon in Beijing, which was more significant compared to biomass burning. Sources and the relative contributions to black carbon and brown carbon during haze and non-haze days will be further discussed.

High Intensity Source Laboratory (HISL)

International Nuclear Information System (INIS)

1992-01-01

The High Intensity Source Laboratory (HISL) is a laboratory facility operated for the US Department of Energy (DOE) by EG ampersand G, Energy Measurements (EG ampersand G/EM). This document is intended as an overview -- primarily for external users -- of the general purposes and capabilities of HISL; numerous technical details are beyond its scope. Moreover, systems at HISL are added, deleted, and modified to suit current needs, and upgraded with continuing development. Consequently, interested parties are invited to contact the HISL manager for detailed, current, technical, and administrative information. The HISL develops and operates pulsed radiation sources with energies, intensities, and pulse widths appropriate for several applications. Principal among these are development, characterization, and calibration of various high-bandwidth radiation detectors and diagnostic systems. Hardness/vulnerability of electronic or other sensitive components to radiation is also tested. In this connection, source development generally focuses on attending (1) the highest possible intensities with (2) reasonably short pulse widths and (3) comprehensive output characterization

Fusing Open Source Intelligence and Handheld Situational Awareness - Benghazi Case Study

Science.gov (United States)

2014-10-01

1 DM-0001694 Fusing Open Source Intelligence and Handheld Situational Awareness Benghazi Case Study Jeff Boleng, PhD Marc Novakouski Gene...command and control element at the CIA compound that would have been monitoring OSINT and other sources of intelligence before the attack and... Source Intelligence and Handheld Situational Awareness - Benghazi Case Study 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6

Sealed source peer review plan

International Nuclear Information System (INIS)

Feldman, Alexander; Leonard, Lee; Burns, Ron

2009-01-01

Sealed sources are known quantities of radioactive materials that have been encapsulated in quantities that produce known radiation fields. Sealed sources have multiple uses ranging from instrument calibration sources to sources that produce radiation fields for experimental applications. The Off-Site Source Recovery (OSR) Project at Los Alamos National Laboratory (LANL), created in 1999, under the direction of the Waste Management Division of the U.S. Department of Energy (DOE) Albuquerque has been assigned the responsibility to recover and manage excess and unwanted radioactive sealed sources from the public and private sector. LANL intends to ship drums containing qualified sealed sources to the Waste Isolation Pilot Plant (WIPP) for disposal. Prior to shipping, these drums must be characterized with respect to radiological content and other parameters. The U. S. Environmental Protection Agency (EPA) requires that ten radionulcides be quantified and reported for every container of waste to be disposed in the WIPP. The methods traditionally approved by the EPA include non-destructive assay (NDA) in accordance with Appendix A of the Contact-Handled Transuranic Waste Acceptance Criteria for the Waste Isolation Pilot Plant (DOE, 2002) (CH WAC). However, because of the nature and pedigree of historical records for sealed sources and the technical infeasibility of performing NDA on these sources, LANL proposes to characterize the content of these waste drums using qualified existing radiological data in lieu of direct measurement. This plan describes the process and documentation requirements for the use of the peer review process to qualify existing data for sealed radiological sources in lieu of perfonning radioassay. The peer review process will be performed in accordance with criteria provided in 40 CFR (section) 194.22 which specifies the use of the NUREG 1297 guidelines. The plan defines the management approach, resources, schedule, and technical requirements

Vacuum simulation and characterization for the Linac4 H- source

Science.gov (United States)

Pasquino, C.; Chiggiato, P.; Michet, A.; Hansen, J.; Lettry, J.

2013-02-01

At CERN, the 160 MeV H- Linac4 will soon replace the 50 MeV proton Linac2. In the H- source two major sources of gas are identified. The first is the pulsed injection at about 0.1 mbar in the plasma chamber. The second is the constant H2 injection up to 10-5 mbar in the LEBT for beam space charge compensation. In addition, the outgassing of materials exposed to vacuum can play an important role in contamination control and global gas balance. To evaluate the time dependent partial pressure profiles in the H- ion source and the RFQ, electrical network - vacuum analogy and test particle Monte Carlo simulation have been used. The simulation outcome indicates that the pressure requirements are in the reach of the proposed vacuum pumping system. Preliminary results show good agreement between the experimental and the simulated pressure profiles; a calibration campaign is in progress to fully benchmark the implemented calculations. Systematic outgassing rate measurements are on-going for critical components in the ion source and RFQ. Amongst them those for the Cu-coated SmCo magnet located in the vacuum system of the biased electron dump electrode, show results lower to stainless steel at room temperature.

Studies on the method of producing radiographic 170Tm source

International Nuclear Information System (INIS)

Maeda, Sho

1976-08-01

A method of producing radiographic 170 Tm source has been studied, including target preparation, neutron irradiation, handling of the irradiated target in the hot cell and source capsules. On the basis of the results, practical 170 Tm radiographic sources (29 -- 49Ci, with pellets 3mm in diameter and 3mm long) were produced in trial by neutron irradiation with the JMTR. (auth.)

Nonpoint source pollution of urban stormwater runoff: a methodology for source analysis.

Science.gov (United States)

Petrucci, Guido; Gromaire, Marie-Christine; Shorshani, Masoud Fallah; Chebbo, Ghassan

2014-09-01

The characterization and control of runoff pollution from nonpoint sources in urban areas are a major issue for the protection of aquatic environments. We propose a methodology to quantify the sources of pollutants in an urban catchment and to analyze the associated uncertainties. After describing the methodology, we illustrate it through an application to the sources of Cu, Pb, Zn, and polycyclic aromatic hydrocarbons (PAH) from a residential catchment (228 ha) in the Paris region. In this application, we suggest several procedures that can be applied for the analysis of other pollutants in different catchments, including an estimation of the total extent of roof accessories (gutters and downspouts, watertight joints and valleys) in a catchment. These accessories result as the major source of Pb and as an important source of Zn in the example catchment, while activity-related sources (traffic, heating) are dominant for Cu (brake pad wear) and PAH (tire wear, atmospheric deposition).

Post-processing of Monte Carlo simulations for rapid BNCT source optimization studies

International Nuclear Information System (INIS)

Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

2000-01-01

A great advantage of some neutron sources, such as accelerator-produced sources, is that they can be tuned to produce different spectra. Unfortunately, optimization studies are often time-consuming and difficult, as they require a lengthy Monte Carlo simulation for each source. When multiple characteristics, such as energy, angle, and spatial distribution of a neutron beam are allowed to vary, an overwhelming number of simulations may be required. Many optimization studies, therefore, suffer from a small number of datapoints, restrictive treatment conditions, or poor statistics. By scoring pertinent information from every particle tally in a Monte Carlo simulation, then applying appropriate source variable weight factors in a post-processing algorithm, a single simulation can be used to model any number of multiple sources. Through this method, the response to a new source can be modeled in minutes or seconds, rather than hours or days, allowing for the analysis of truly variable source conditions of much greater resolution than is normally possible when a new simulation must be run for each datapoint in a study. This method has been benchmarked and used to recreate optimization studies in a small fraction of the time spent in the original studies

Tank 4 Characterization, Settling, And Washing Studies

International Nuclear Information System (INIS)

Bannochie, C.; Pareizs, J.; Click, D.; Zamecnik, J.

2009-01-01

A sample of PUREX sludge from Tank 4 was characterized, and subsequently combined with a Tank 51 sample (Tank 51-E1) received following Al dissolution, but prior to a supernate decant by the Tank Farm, to perform a settling and washing study to support Sludge Batch 6 preparation. The sludge source for the majority of the Tank 51-E1 sample is Tank 12 HM sludge. The Tank 51-E1 sample was decanted by SRNL prior to use in the settling and washing study. The Tank 4 sample was analyzed for chemical composition including noble metals. The characterization of the Tank 51-E1 sample, used here in combination with the Tank 4 sample, was reported previously. SRNL analyses on Tank 4 were requested by Liquid Waste Engineering (LWE) via Technical Task Request (TTR) HLE-TTR-2009-103. The sample preparation work is governed by Task Technical and Quality Assurance Plan (TTQAP), and analyses were controlled by an Analytical Study Plan and modifications received via customer communications. Additional scope included a request for a settling study of decanted Tank 51-E1 and a blend of decanted Tank 51-E1 and Tank 4, as well as a washing study to look into the fate of undissolved sulfur observed during the Tank 4 characterization. The chemistry of the Tank 4 sample was modeled with OLI Systems, Inc. StreamAnalyzer to determine the likelihood that sulfate could exist in this sample as insoluble Burkeite (2Na 2 SO 4 · Na 2 CO 3 ). The OLI model was also used to predict the composition of the blended tank materials for the washing study. The following conclusions were drawn from the Tank 4 analytical results reported here: (1) Any projected blend of Tank 4 and the current Tank 51 contents will produce a SB6 composition that is lower in Ca and U than the current SB5 composition being processed by DWPF. (2) Unwashed Tank 4 has a relatively large initial S concentration of 3.68 wt% on a total solids basis, and approximately 10% of the total S is present as an insoluble or undissolved form

Source characterization of ambient fine aerosol in Singapore during a haze episode in 2015

Science.gov (United States)

Hapsari Budisulistiorini, Sri; Riva, Matthieu; Williams, Michael; Miyakawa, Takuma; Komazaki, Yuichi; Chen, Jing; Surratt, Jason; Kuwata, Mikinori

2017-04-01

Recurring transboundary haze from Indonesia peatland fires in the previous decades has significantly elevated particulate matter (PM) concentration in Southeast Asia, particularly during the 2015 El Niño event. Previous studies have investigated chemical composition of particles emitted during haze episodes; however, they were limited to time-integrated samples and the number of identified compounds. Low time-resolution measurement results in co-variance of PM sources; therefore, higher time-resolution measurement is important in PM source apportionment. Between October 10-31, 2015, Aerodyne Time-of-Flight Aerosol Chemical Speciation Monitor (ToF-ACSM) was deployed for real-time chemical characterization of ambient submicron PM (NR-PM1) in Singapore. Simultaneously, PM2.5 filter samples were collected for molecular-level organic aerosol (OA) constituents, organic carbon (OC), elemental carbon (EC) and water-soluble OC (WSOC) analyses. OA constituents were quantified by gas chromatography interfaced to electron ionization mass spectrometry (GC/EI-MS) and ultra-performance liquid chromatography interfaced to electrospray ionization high-resolution quadrupole time-of-flight mass spectrometer operated in the negative ion mode (UPLC/(-)ESI-HR-Q-TOFMS). OA and SO42- are dominant components of the haze particles, accounting for ˜77% and ˜12% of the total NR-PM1 mass, respectively. OC/EC ratio of 4.8 might indicate formation of secondary OA (SOA) and aerosols from biomass burning, including those from peat burning. OA fraction from ToF-ACSM measurements was analyzed for source apportionment using a bilinear model through multi-linear engine algorithm (ME-2) in graphical user interface SoFi (Source Finder). Five OA factors were identified: hydrocarbon-like OA (HOA), biomass burning OA (BBOA), peat burning OA (PBOA), low-volatility oxygenated OA (LV-OOA), and semi-volatile oxygenated OA (SV-OOA). The HOA factor shows a distinct diurnal profile peaking in the morning and

The Chandra Source Catalog: Background Determination and Source Detection

Science.gov (United States)

McCollough, Michael; Rots, Arnold; Primini, Francis A.; Evans, Ian N.; Glotfelty, Kenny J.; Hain, Roger; Anderson, Craig S.; Bonaventura, Nina R.; Chen, Judy C.; Davis, John E.; Doe, Stephen M.; Evans, Janet D.; Fabbiano, Giuseppina; Galle, Elizabeth C.; Danny G. Gibbs, II; Grier, John D.; Hall, Diane M.; Harbo, Peter N.; He, Xiang Qun (Helen); Houck, John C.; Karovska, Margarita; Kashyap, Vinay L.; Lauer, Jennifer; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph B.; Mitschang, Arik W.; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Nowak, Michael A.; Plummer, David A.; Refsdal, Brian L.; Siemiginowska, Aneta L.; Sundheim, Beth A.; Tibbetts, Michael S.; van Stone, David W.; Winkelman, Sherry L.; Zografou, Panagoula

2009-09-01

The Chandra Source Catalog (CSC) is a major project in which all of the pointed imaging observations taken by the Chandra X-Ray Observatory are used to generate one of the most extensive X-ray source catalog produced to date. Early in the development of the CSC it was recognized that the ability to estimate local background levels in an automated fashion would be critical for essential CSC tasks such as source detection, photometry, sensitivity estimates, and source characterization. We present a discussion of how such background maps are created directly from the Chandra data and how they are used in source detection. The general background for Chandra observations is rather smoothly varying, containing only low spatial frequency components. However, in the case of ACIS data, a high spatial frequency component is added that is due to the readout streaks of the CCD chips. We discuss how these components can be estimated reliably using the Chandra data and what limitations and caveats should be considered in their use. We will discuss the source detection algorithm used for the CSC and the effects of the background images on the detection results. We will also touch on some the Catalog Inclusion and Quality Assurance criteria applied to the source detection results. This work is supported by NASA contract NAS8-03060 (CXC).

Filling Source Feedthrus with Alumina/Molybdenum CND50 Cermet: Experimental, Theoretical, and Computational Approaches

International Nuclear Information System (INIS)

STUECKER, JOHN N.; CESARANO III, JOSEPH; CORRAL, ERICA LORRANE; SHOLLENBERGER, KIM ANN; ROACH, R. ALLEN; TORCZYNSKI, JOHN R.; THOMAS, EDWARD V.; VAN ORNUM, DAVID J.

2001-01-01

This report is a summary of the work completed in FY00 for science-based characterization of the processes used to fabricate cermet vias in source feedthrus. In particular, studies were completed to characterize the CND50 cermet slurry, characterize solvent imbibition, and identify critical via filling variables. These three areas of interest are important to several processes pertaining to the production of neutron generator tubes. Rheological characterization of CND50 slurry prepared with 94ND2 and Sandi94 primary powders were also compared. The 94ND2 powder was formerly produced at the GE Pinellas Plant and the Sandi94 is the new replacement powder produced at CeramTec. Processing variables that may effect the via-filling process were also studied and include: the effect of solids loading in the CND50 slurry; the effect of milling time; and the effect of Nuosperse (a slurry ''conditioner''). Imbibition characterization included a combination of experimental, theoretical, and computational strategies to determine solvent migration though complex shapes, specifically vias in the source feedthru component. Critical factors were determined using a controlled set of experiments designed to identify those variables that influence the occurrence of defects within the cermet filled via. These efforts were pursued to increase part production reliability, understand selected fundamental issues that impact the production of slurry-filled parts, and validate the ability of the computational fluid dynamics code, GOMA, to simulate these processes. Suggestions are made for improving the slurry filling of source feedthru vias

Sources of Strategic Information in Farm Management in Poland. Study Results

Directory of Open Access Journals (Sweden)

Jacek Jaworski

2017-03-01

Full Text Available Purposes: The main goal of the paper is to determine the signifcance of selected sources of strategic information, used by Polish farmers in decision making. In addition, an attempt was made to determine the factors impacting the evaluation of those sources among the traits of the farmer and his farm. Methodology: Data was gathered using the questionnaire method and analysed with standard tools of descriptive statistics. Findings: The farmers deemed personalised sources of strategic information the most important, especially agricultural advisers, input suppliers and buyers of agricultural products. From among institutional (non-personalised sources, local government and the chamber of agriculture were signifcant. Business information agencies and survey companies are the least important sources for farmers. The characteristics of the surroundings of the farm – specifcally, its geographic location and the size of settlement where it is located proved to have the widest impact on the evaluation of the sources included in the study. From among the organisational factors, only farm size has a signifcant impact. Research limitations/implications: The study was confned to a representative group of farmers in Poland. A closed list of sources of strategic information was used. Originality/value: The study results contribute to the knowledge on the functioning of Polish agriculture and may also be used in comparative studies, characterising this sector’s diversity within Europe. They can in turn contribute to properly focusing on supporting the policy of balanced agriculture development in the EU.

Radiation field characterization and shielding studies for the ELI Beamlines facility

Energy Technology Data Exchange (ETDEWEB)

Ferrari, A., E-mail: a.ferrari@hzdr.de [Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, PF 510119, 01314 Dresden (Germany); Amato, E. [Department of Radiological Sciences, Messina University (Italy); Margarone, D. [ELI Beamlines Project, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic); PALS Centre, Za Slovankou, 18200 Prague (Czech Republic); Cowan, T. [Institute of Radiation Physics, Helmholtz-Zentrum Dresden-Rossendorf, PF 510119, 01314 Dresden (Germany); Korn, G. [ELI Beamlines Project, Institute of Physics of the ASCR, Na Slovance 2, 18221 Prague (Czech Republic)

2013-05-01

The ELI (Extreme Light Infrastructure) Beamlines facility in the Czech Republic, which is planned to complete the installation in 2015, is one of the four pillars of the ELI European project. Several laser beamlines with ultrahigh intensities and ultrashort pulses are foreseen, offering versatile radiation sources in an unprecedented energy range: laser-driven particle beams are expected to range between 1 and 50 GeV for electrons and from 100 MeV up to 3 GeV for protons. The number of particles delivered per laser shot is estimated to be 10{sup 9}–10{sup 10} for the electron beams and 10{sup 10}–10{sup 12} for the proton beams. The high energy and current values of the produced particles, together with the potentiality to operate at 10 Hz laser repetition rate, require an accurate study of the primary and secondary radiation fields to optimize appropriate shielding solutions: this is a key issue to minimize prompt and residual doses in order to protect the personnel, reduce the radiation damage of electronic devices and avoid strong limitations in the operational time. A general shielding study for the 10 PW (0.016 Hz) and 2 PW (10 Hz) laser beamlines is presented here. Starting from analytical calculations, as well as from dedicated simulations, the main electron and proton fields produced in the laser-matter interaction have been described and used to characterize the “source terms” in full simulations with the Monte Carlo code FLUKA. The secondary radiation fields have been then analyzed to assess a proper shielding. The results of this study and the proposed solutions for the beam dumps of the high energy beamlines, together with a cross-check analysis performed with the Monte Carlo code GEANT4, are presented.

Intra-urban biomonitoring: Source apportionment using tree barks to identify air pollution sources.

Science.gov (United States)

Moreira, Tiana Carla Lopes; de Oliveira, Regiani Carvalho; Amato, Luís Fernando Lourenço; Kang, Choong-Min; Saldiva, Paulo Hilário Nascimento; Saiki, Mitiko

2016-05-01

It is of great interest to evaluate if there is a relationship between possible sources and trace elements using biomonitoring techniques. In this study, tree bark samples of 171 trees were collected using a biomonitoring technique in the inner city of São Paulo. The trace elements (Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, Rb, S, Sr and Zn) were determined by the energy dispersive X-ray fluorescence (EDXRF) spectrometry. The Principal Component Analysis (PCA) was applied to identify the plausible sources associated with tree bark measurements. The greatest source was vehicle-induced non-tailpipe emissions derived mainly from brakes and tires wear-out and road dust resuspension (characterized with Al, Ba, Cu, Fe, Mn and Zn), which was explained by 27.1% of the variance, followed by cement (14.8%), sea salt (11.6%) and biomass burning (10%), and fossil fuel combustion (9.8%). We also verified that the elements related to vehicular emission showed different concentrations at different sites of the same street, which might be helpful for a new street classification according to the emission source. The spatial distribution maps of element concentrations were obtained to evaluate the different levels of pollution in streets and avenues. Results indicated that biomonitoring techniques using tree bark can be applied to evaluate dispersion of air pollution and provide reliable data for the further epidemiological studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Study of liquid hydrogen and liquid deuterium cold neutron sources

International Nuclear Information System (INIS)

Harig, H.D.

1969-01-01

In view of the plant of the cold neutron source for a high flux reactor (maximal thermal flux of about 10 15 n/cm 2 s) an experimental study of several cold sources of liquid hydrogen and liquid deuterium has been made in a low power reactor (100 kW, about 10 12 n/cm 2 s). We have investigated: -cold neutron sources of liquid hydrogen shaped as annular layers of different thickness. Normal liquid hydrogen was used as well as hydrogen with a high para-percentage. -Cold neutron sources of liquid deuterium in cylinders of 18 and 38 cm diameter. In this case the sources could be placed into different positions to the reactor core within the heavy water reflector. This report gives a general description of the experimental device and deals more detailed with the design of the cryogenic systems. Then, the measured results are communicated, interpreted and finally compared with those of a theoretical study about the same cold moderators which have been the matter of the experimental investigation. (authors) [fr

Experimental study of adsorption chiller driven by variable heat source

Energy Technology Data Exchange (ETDEWEB)

Wang, D.C.; Wang, Y.J.; Zhang, J.P.; Tian, X.L. [College of Electromechanical Engineering, Qingdao University, Qingdao 266071 (China); Wu, J.Y. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China)

2008-05-15

A silica gel-water adsorption chiller has been developed in recent years and has been applied in an air conditioning system driven by solar energy. The heat source used to drive the adsorption chiller is variable at any moment because the solar radiation intensity or the waste heat from engines varies frequently. An adsorption cooling system may be badly impacted by a variable heat source with temperature variations in a large range. In this work, a silica gel-water adsorption chiller driven by a variable heat source is experimentally studied. The influences of the variable heat source on the performance of the chiller are analyzed, especially for a continuous temperature increase process and a continuous temperature decrease process of the heat source. As an example, the dynamic characteristics of the heat source are also analyzed when solar energy is taken as the heat source of the adsorption chiller. According to the experimental results for the adsorption chiller and the characteristics of the heat source from solar energy, control strategies of the adsorption chiller driven by solar energy are proposed. (author)

Experimental study of adsorption chiller driven by variable heat source

International Nuclear Information System (INIS)

Wang, D.C.; Wang, Y.J.; Zhang, J.P.; Tian, X.L.; Wu, J.Y.

2008-01-01

A silica gel-water adsorption chiller has been developed in recent years and has been applied in an air conditioning system driven by solar energy. The heat source used to drive the adsorption chiller is variable at any moment because the solar radiation intensity or the waste heat from engines varies frequently. An adsorption cooling system may be badly impacted by a variable heat source with temperature variations in a large range. In this work, a silica gel-water adsorption chiller driven by a variable heat source is experimentally studied. The influences of the variable heat source on the performance of the chiller are analyzed, especially for a continuous temperature increase process and a continuous temperature decrease process of the heat source. As an example, the dynamic characteristics of the heat source are also analyzed when solar energy is taken as the heat source of the adsorption chiller. According to the experimental results for the adsorption chiller and the characteristics of the heat source from solar energy, control strategies of the adsorption chiller driven by solar energy are proposed

Study of extragalactic sources with H.E.S.S

International Nuclear Information System (INIS)

Giebels, Berrie

2007-01-01

The field of Very High Energy (VHE) γ-ray emitting extragalactic sources has considerably evolved since the new generation of atmospheric Cerenkov telescopes (ACT) of improved sensitivity, such as H.E.S.S. array and the MAGIC ACT, have started operating. This has led to a wealth of new clues about emission mechanisms at high energy through the discovery of new sources, more accurate spectra and temporal studies of sources known previously, and simultaneous multi-wavelength (MWL) campaigns since broad band variability is a key phenomenon to the underlying physical mechanisms at play. The fact that some of these new sources are located at redshifts close to z ∼ 0.2 makes them powerful probes of the Extragalactic Background Light (EBL) through the attenuation of γ-rays above 100 GeV

Improved thermal source term generation capability for use in performance assessment and system studies

International Nuclear Information System (INIS)

King, J.; Rhodes, C.

1994-01-01

This paper describes work performed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating (M ampersand O) Contractor to improve spent nuclear fuel (SNF) waste stream characterization for system studies. It discusses how these new capabilities may be exploited for thermal source term generation for use in repository performance assessment modeling. SNF historical discharges have been exhaustively tracked, and significant effort has gone into capturing, verifying, and electronically managing spent fuel inventory data. Future discharge projections are produced annually by the Energy Information Administration (EIA) using sophisticated computer models. The output of these models is coupled with annually updated SNF historical discharges to produce what is referred to as the open-quotes reactor database.close quotes This database and related data are published in a variety of ways including on magnetic media for consistent use by analysts or other interested parties

Post-processing of Monte Carlo simulations for rapid BNCT source optimization studies

International Nuclear Information System (INIS)

Bleuel, D.L.; Chu, W.T.; Donahue, R.J.; Ludewigt, B.A.; Vujic, J.

2000-01-01

A great advantage of some neutron sources, such as accelerator-produced sources, is that they can be tuned to produce different spectra. Unfortunately, optimization studies are often time-consuming and difficult, as they require a lengthy Monte Carlo simulation for each source. When multiple characteristics, such as energy, angle, and spatial distribution of a neutron beam are allowed to vary, an overwhelming number of simulations may be required. Many optimization studies, therefore, suffer from a small number of data points, restrictive treatment conditions, or poor statistics. By scoring pertinent information from every particle tally in a Monte Carlo simulation, then applying appropriate source variable weight factors in a post-processing algorithm; a single simulation can be used to model any number of multiple sources. Through this method, the response to a new source can be modeled in minutes or seconds, rather than hours or days, allowing for the analysis of truly variable source conditions of much greater resolution than is normally possible when a new simulation must be run for each data point in a study. This method has been benchmarked and used to recreate optimization studies in a small fraction of the time spent in the original studies. (author)

Dilemmas within Commercial Involvement in Open Source Software

DEFF Research Database (Denmark)

Ciesielska, Malgorzata; Westenholz, Ann

2016-01-01

to free-riding. There are six levels of commercial involvement in open source communities, and each of them is characterized by a different dilemma. Originality/value – The paper sheds light on the various level of involvement of business in open source movement and emphasize that the popularized “open......Purpose – The purpose of this paper is to contribute to the literature about the commercial involvement in open source software, levels of this involvement and consequences of attempting to mix various logics of action. Design/methodology/approach – This paper uses the case study approach based...... on mixed methods: literature reviews and news searches, electronic surveys, qualitative interviews and observations. It combines discussions from several research projects as well as previous publications to present the scope of commercial choices within open source software and their consequences...

A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model

International Nuclear Information System (INIS)

Hiatt, Jessica R.; Davis, Stephen D.; Rivard, Mark J.

2015-01-01

Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10 10 histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an 125 I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose function

A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model

Energy Technology Data Exchange (ETDEWEB)

Hiatt, Jessica R. [Department of Radiation Oncology, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, Rhode Island 02903 (United States); Davis, Stephen D. [Department of Medical Physics, McGill University Health Centre, Montreal, Quebec H3G 1A4 (Canada); Rivard, Mark J., E-mail: mark.j.rivard@gmail.com [Department of Radiation Oncology, Tufts University School of Medicine, Boston, Massachusetts 02111 (United States)

2015-06-15

Purpose: The model S700 Axxent electronic brachytherapy source by Xoft, Inc., was characterized by Rivard et al. in 2006. Since then, the source design was modified to include a new insert at the source tip. Current study objectives were to establish an accurate source model for simulation purposes, dosimetrically characterize the new source and obtain its TG-43 brachytherapy dosimetry parameters, and determine dose differences between the original simulation model and the current model S700 source design. Methods: Design information from measurements of dissected model S700 sources and from vendor-supplied CAD drawings was used to aid establishment of an updated Monte Carlo source model, which included the complex-shaped plastic source-centering insert intended to promote water flow for cooling the source anode. These data were used to create a model for subsequent radiation transport simulations in a water phantom. Compared to the 2006 simulation geometry, the influence of volume averaging close to the source was substantially reduced. A track-length estimator was used to evaluate collision kerma as a function of radial distance and polar angle for determination of TG-43 dosimetry parameters. Results for the 50 kV source were determined every 0.1 cm from 0.3 to 15 cm and every 1° from 0° to 180°. Photon spectra in water with 0.1 keV resolution were also obtained from 0.5 to 15 cm and polar angles from 0° to 165°. Simulations were run for 10{sup 10} histories, resulting in statistical uncertainties on the transverse plane of 0.04% at r = 1 cm and 0.06% at r = 5 cm. Results: The dose-rate distribution ratio for the model S700 source as compared to the 2006 model exceeded unity by more than 5% for roughly one quarter of the solid angle surrounding the source, i.e., θ ≥ 120°. The radial dose function diminished in a similar manner as for an {sup 125}I seed, with values of 1.434, 0.636, 0.283, and 0.0975 at 0.5, 2, 5, and 10 cm, respectively. The radial dose

Characterization and source apportionment of health risks from ambient PM10 in Hong Kong over 2000-2011

Science.gov (United States)

Li, Zhiyuan; Yuan, Zibing; Li, Ying; Lau, Alexis K. H.; Louie, Peter K. K.

2015-12-01

Atmospheric particulate matter (PM) pollution is a major public health concern in Hong Kong. In this study, the spatiotemporal variations of health risks from ambient PM10 from seven air quality monitoring stations between 2000 and 2011 were analyzed. Positive matrix factorization (PMF) was adopted to identify major source categories of ambient PM10 and quantify their contributions. Afterwards, a point-estimated risk model was used to identify the inhalation cancer and non-cancer risks of PM10 sources. The long-term trends of the health risks from classified local and non-local sources were explored. Furthermore, the reason for the increase of health risks during high PM10 days was discussed. Results show that vehicle exhaust source was the dominant inhalation cancer risk (ICR) contributor (72%), whereas trace metals and vehicle exhaust sources contributed approximately 27% and 21% of PM10 inhalation non-cancer risk (INCR), respectively. The identified local sources accounted for approximately 80% of the ICR in Hong Kong, while contribution percentages of the non-local and local sources for INCR are comparable. The clear increase of ICR at high PM days was mainly attributed to the increase of contributions from coal combustion/biomass burning and secondary sulfate, while the increase of INCR at high PM days was attributed to the increase of contributions from the sources coal combustion/biomass burning, secondary nitrate, and trace metals. This study highlights the importance of health risk-based source apportionment in air quality management with protecting human health as the ultimate target.

Long period seismic source characterization at Popocatépetl volcano, Mexico

Science.gov (United States)

Arciniega-Ceballos, Alejandra; Dawson, Phillip; Chouet, Bernard A.

2012-01-01

The seismicity of Popocatépetl is dominated by long-period and very-long period signals associated with hydrothermal processes and magmatic degassing. We model the source mechanism of repetitive long-period signals in the 0.4–2 s band from a 15-station broadband network by stacking long-period events with similar waveforms to improve the signal-to-noise ratio. The data are well fitted by a point source located within the summit crater ~250 m below the crater floor and ~200 m from the inferred magma conduit. The inferred source includes a volumetric component that can be modeled as resonance of a horizontal steam-filled crack and a vertical single force component. The long-period events are thought to be related to the interaction between the magmatic system and a perched hydrothermal system. Repetitive injection of fluid into the horizontal fracture and subsequent sudden discharge when a critical pressure threshold is met provides a non-destructive source process.

Processing and characterization of diatom nanoparticles and microparticles as potential source of silicon for bone tissue engineering

Energy Technology Data Exchange (ETDEWEB)

Le, Thi Duy Hanh [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Bonani, Walter [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Speranza, Giorgio [Center for Materials and Microsystems, PAM-SE, Fondazione Bruno Kessler, Trento (Italy); Sglavo, Vincenzo; Ceccato, Riccardo [Department of Industrial Engineering, University of Trento, Trento (Italy); Maniglio, Devid; Motta, Antonella [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy); Migliaresi, Claudio, E-mail: claudio.migliaresi@unitn.it [Department of Industrial Engineering, University of Trento, Trento (Italy); BIOtech Research Center and European Institute of Excellence on Tissue Engineering and Regenerative Medicine, Trento (Italy); Interuniversity Consortium for Science and Technology of Materials, Trento Research Unit, Trento (Italy)

2016-02-01

Silicon plays an important role in bone formation and maintenance, improving osteoblast cell function and inducing mineralization. Often, bone deformation and long bone abnormalities have been associated with silica/silicon deficiency. Diatomite, a natural deposit of diatom skeleton, is a cheap and abundant source of biogenic silica. The aim of the present study is to validate the potential of diatom particles derived from diatom skeletons as silicon-donor materials for bone tissue engineering applications. Raw diatomite (RD) and calcined diatomite (CD) powders were purified by acid treatments, and diatom microparticles (MPs) and nanoparticles (NPs) were produced by fragmentation of purified diatoms under alkaline conditions. The influence of processing on the surface chemical composition of purified diatomites was evaluated by X-ray photoelectron spectroscopy (XPS). Diatoms NPs were also characterized in terms of morphology and size distribution by transmission electron microscopy (TEM) and Dynamic light scattering (DLS), while diatom MPs morphology was analyzed by scanning electron microscopy (SEM). Surface area and microporosity of the diatom particles were evaluated by nitrogen physisorption methods. Release of silicon ions from diatom-derived particles was demonstrated using inductively coupled plasma optical emission spectrometry (ICP/OES); furthermore, silicon release kinetic was found to be influenced by diatomite purification method and particle size. Diatom-derived microparticles (MPs) and nanoparticles (NPs) showed limited or no cytotoxic effect in vitro depending on the administration conditions. - Highlights: • Diatomite is a natural source of silica and has a potential as silicon-donor for bone regenerative applications. • Diatom particles derived from purified diatom skeletons were prepared by fragmentation under extreme alkaline condition. • Dissolution of diatom particles derived from diatom skeletons in DI water depend on purification method

Application of optical emission spectroscopy to high current proton sources

International Nuclear Information System (INIS)

Castro, G; Mazzaglia, M; Nicolosi, D; Mascali, D; Reitano, R; Celona, L; Leonardi, O; Leone, F; Naselli, E; Neri, L; Torrisi, G; Gammino, S; Zaniol, B

2017-01-01

Optical Emission Spectroscopy (OES) represents a very reliable technique to carry out non-invasive measurements of plasma density and plasma temperature in the range of tens of eV. With respect to other diagnostics, it also can characterize the different populations of neutrals and ionized particles constituting the plasma. At INFN-LNS, OES techniques have been developed and applied to characterize the plasma generated by the Flexible Plasma Trap, an ion source used as 'testbench' of the proton source built for European Spallation Source. This work presents the characterization of the parameters of a hydrogen plasma in different conditions of neutral pressure, microwave power and magnetic field profile, along with perspectives for further upgrades of the OES diagnostics system. (paper)

Characterization study of industrial waste glass as starting material ...

African Journals Online (AJOL)

In present study, an industrial waste glass was characterized and the potential to assess as starting material in development of bioactive materials was investigated. A waste glass collected from the two different glass industry was grounded to fine powder. The samples were characterized using X-ray fluorescence (XRF), ...

An experimental MOSFET approach to characterize (192)Ir HDR source anisotropy.

Science.gov (United States)

Toye, W C; Das, K R; Todd, S P; Kenny, M B; Franich, R D; Johnston, P N

2007-09-07

The dose anisotropy around a (192)Ir HDR source in a water phantom has been measured using MOSFETs as relative dosimeters. In addition, modeling using the EGSnrc code has been performed to provide a complete dose distribution consistent with the MOSFET measurements. Doses around the Nucletron 'classic' (192)Ir HDR source were measured for a range of radial distances from 5 to 30 mm within a 40 x 30 x 30 cm(3) water phantom, using a TN-RD-50 MOSFET dosimetry system with an active area of 0.2 mm by 0.2 mm. For each successive measurement a linear stepper capable of movement in intervals of 0.0125 mm re-positioned the MOSFET at the required radial distance, while a rotational stepper enabled angular displacement of the source at intervals of 0.9 degrees . The source-dosimeter arrangement within the water phantom was modeled using the standardized cylindrical geometry of the DOSRZnrc user code. In general, the measured relative anisotropy at each radial distance from 5 mm to 30 mm is in good agreement with the EGSnrc simulations, benchmark Monte Carlo simulation and TLD measurements where they exist. The experimental approach employing a MOSFET detection system of small size, high spatial resolution and fast read out capability allowed a practical approach to the determination of dose anisotropy around a HDR source.

Open-Source RTOS Space Qualification: An RTEMS Case Study

Science.gov (United States)

Zemerick, Scott

2017-01-01

NASA space-qualification of reusable off-the-shelf real-time operating systems (RTOSs) remains elusive due to several factors notably (1) The diverse nature of RTOSs utilized across NASA, (2) No single NASA space-qualification criteria, lack of verification and validation (V&V) analysis, or test beds, and (3) different RTOS heritages, specifically open-source RTOSs and closed vendor-provided RTOSs. As a leader in simulation test beds, the NASA IV&V Program is poised to help jump-start and lead the space-qualification effort of the open source Real-Time Executive for Multiprocessor Systems (RTEMS) RTOS. RTEMS, as a case-study, can be utilized as an example of how to qualify all RTOSs, particularly the reusable non-commercial (open-source) ones that are gaining usage and popularity across NASA. Qualification will improve the overall safety and mission assurance of RTOSs for NASA-agency wide usage. NASA's involvement in space-qualification of an open-source RTOS such as RTEMS will drive the RTOS industry toward a more qualified and mature open-source RTOS product.

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 ...

Ultra-luminous X-ray sources and intermediate-mass black holes

International Nuclear Information System (INIS)

Cseh, David

2012-01-01

More than ten years ago, the discovery of Ultra-luminous X-ray sources (ULXs) has opened up an entirely new field in astrophysics. Many ideas were developed to explain the nature of these sources, like their emission mechanism, mass, and origin, without any strong conclusions. Their discovery boosted the fields of X-ray binaries, accretion physics, stellar evolution, cosmology, black hole formation and growth, due to the concept of intermediate-mass black holes (IMBHs). Since their discovery is related to the domain of X-ray astrophysics, there have been very few studies made in other wavelengths. This thesis focuses on the multiwavelength nature of Ultra-luminous X-ray sources and intermediate-mass black holes from various aspects, which help to overcome some difficulties we face today. First, I investigated the accretion signatures of a putative intermediate-mass black hole in a particular globular cluster. To this purpose, I characterized the nature of the innermost X-ray sources in the cluster. Then I calculated an upper limit on the mass of the black hole by studying possible accretion efficiencies and rates based on the dedicated X-ray and radio observations. The accreting properties of the source was described with standard spherical accretion and in the context of inefficient accretion. Secondly, I attempted to dynamically measure the mass of the black hole in a particular ULX via optical spectroscopy. I discovered that a certain emission line has a broad component that markedly shifts in wavelength. I investigated the possibility whether this line originates in the accretion disk, and thus might trace the orbital motion of the binary system. I also characterized the parameters of the binary system, such as the mass function, possible orbital separation, the size of the line-emitting region, and an upper limit on the mass of the black hole. Then I studied the environment of a number of ULXs that are associated with large-scale optical and radio nebulae. I

Comparison of Protein Extracts from Various Unicellular Green Sources.

Science.gov (United States)

Teuling, Emma; Wierenga, Peter A; Schrama, Johan W; Gruppen, Harry

2017-09-13

Photosynthetic unicellular organisms are considered as promising alternative protein sources. The aim of this study is to understand the extent to which these green sources differ with respect to their gross composition and how these differences affect the final protein isolate. Using mild isolation techniques, proteins were extracted and isolated from four different unicellular sources (Arthrospira (spirulina) maxima, Nannochloropsis gaditana, Tetraselmis impellucida, and Scenedesmus dimorphus). Despite differences in protein contents of the sources (27-62% w/w) and in protein extractability (17-74% w/w), final protein isolates were obtained that had similar protein contents (62-77% w/w) and protein yields (3-9% w/w). Protein solubility as a function of pH was different between the sources and in ionic strength dependency, especially at pH < 4.0. Overall, the characterization and extraction protocol used allows a relatively fast and well-described isolation of purified proteins from novel protein sources.

High-efficiency thermal ionization sources for mass spectrometry

International Nuclear Information System (INIS)

Olivares, Jose A.

1996-01-01

A version of the thermal ionization cavity (TIC) source developed specifically for use in mass spectrometry is presented. The performance of this ion source has been characterized extensively both with the use of an isotope separator and a quadrupole mass spectrometer. A detailed description of the TIC source for mass spectrometry is given along with the performance characteristics observed

Optically pumped semiconductor lasers: Conception and characterization of a single mode source for Cesium atoms manipulation

International Nuclear Information System (INIS)

Cocquelin, B.

2009-02-01

Lasers currently used in atomic clocks or inertial sensors are suffering from a lack of power, narrow linewidth or compactness for future spatial missions. Optically pumped semiconductor lasers, which combine the approach of classical solid state lasers and the engineering of semiconductor laser, are considered here as a candidate to a metrological laser source dedicated to the manipulation of Cesium atoms in these instruments. These lasers have demonstrated high power laser emission in a circular single transverse mode, as well as single longitudinal mode emission, favoured by the semiconductor structure and the external cavity design. We study the definition and the characterization of a proper semiconductor structure for the cooling and the detection of Cesium atoms at 852 nm. A compact and robust prototype tunable on the Cesium D2 hyperfine structure is built. The laser frequency is locked to an atomic transition thanks to a saturated absorption setup. The emission spectral properties are investigated, with a particular attention to the laser frequency noise and the laser linewidth. Finally, we describe and model the thermal properties of the semiconductor structure, which enables the simulation of the laser power characteristic. The experimental parameters are optimised to obtain the maximum output power with our structure. Thanks to our analysis, we propose several ways to overcome these limitations, by reducing the structure heating. (authors)

Text mining and visualization case studies using open-source tools

CERN Document Server

Chisholm, Andrew

2016-01-01

Text Mining and Visualization: Case Studies Using Open-Source Tools provides an introduction to text mining using some of the most popular and powerful open-source tools: KNIME, RapidMiner, Weka, R, and Python. The contributors-all highly experienced with text mining and open-source software-explain how text data are gathered and processed from a wide variety of sources, including books, server access logs, websites, social media sites, and message boards. Each chapter presents a case study that you can follow as part of a step-by-step, reproducible example. You can also easily apply and extend the techniques to other problems. All the examples are available on a supplementary website. The book shows you how to exploit your text data, offering successful application examples and blueprints for you to tackle your text mining tasks and benefit from open and freely available tools. It gets you up to date on the latest and most powerful tools, the data mining process, and specific text mining activities.

LIGHT SOURCE: A simulation study of Tsinghua Thomson scattering X-ray source

Science.gov (United States)

Tang, Chuan-Xiang; Li, Ren-Kai; Huang, Wen-Hui; Chen, Huai-Bi; Du, Ying-Chao; Du, Qiang; Du, Tai-Bin; He, Xiao-Zhong; Hua, Jian-Fei; Lin, Yu-Zhen; Qian, Hou-Jun; Shi, Jia-Ru; Xiang, Dao; Yan, Li-Xin; Yu, Pei-Cheng

2009-06-01

Thomson scattering X-ray sources are compact and affordable facilities that produce short duration, high brightness X-ray pulses enabling new experimental capacities in ultra-fast science studies, and also medical and industrial applications. Such a facility has been built at the Accelerator Laboratory of Tsinghua University, and upgrade is in progress. In this paper, we present a proposed layout of the upgrade with design parameters by simulation, aiming at high X-ray pulses flux and brightness, and also enabling advanced dynamics studies and applications of the electron beam. Design and construction status of main subsystems are also presented.

The Chandra Source Catalog: Source Properties and Data Products

Science.gov (United States)

Rots, Arnold; Evans, Ian N.; Glotfelty, Kenny J.; Primini, Francis A.; Zografou, Panagoula; Anderson, Craig S.; Bonaventura, Nina R.; Chen, Judy C.; Davis, John E.; Doe, Stephen M.; Evans, Janet D.; Fabbiano, Giuseppina; Galle, Elizabeth C.; Gibbs, Danny G., II; Grier, John D.; Hain, Roger; Hall, Diane M.; Harbo, Peter N.; He, Xiang Qun (Helen); Houck, John C.; Karovska, Margarita; Kashyap, Vinay L.; Lauer, Jennifer; McCollough, Michael L.; McDowell, Jonathan C.; Miller, Joseph B.; Mitschang, Arik W.; Morgan, Douglas L.; Mossman, Amy E.; Nichols, Joy S.; Nowak, Michael A.; Plummer, David A.; Refsdal, Brian L.; Siemiginowska, Aneta L.; Sundheim, Beth A.; Tibbetts, Michael S.; van Stone, David W.; Winkelman, Sherry L.

2009-09-01

The Chandra Source Catalog (CSC) is breaking new ground in several areas. There are two aspects that are of particular interest to the users: its evolution and its contents. The CSC will be a living catalog that becomes richer, bigger, and better in time while still remembering its state at each point in time. This means that users will be able to take full advantage of new additions to the catalog, while retaining the ability to back-track and return to what was extracted in the past. The CSC sheds the limitations of flat-table catalogs. Its sources will be characterized by a large number of properties, as usual, but each source will also be associated with its own specific data products, allowing users to perform mini custom analysis on the sources. Source properties fall in the spatial (position, extent), photometric (fluxes, count rates), spectral (hardness ratios, standard spectral fits), and temporal (variability probabilities) domains, and are all accompanied by error estimates. Data products cover the same coordinate space and include event lists, images, spectra, and light curves. In addition, the catalog contains data products covering complete observations: event lists, background images, exposure maps, etc. This work is supported by NASA contract NAS8-03060 (CXC).

1994 Characterization report for the state approved land disposal site