Science.gov

Sample records for gas distribution mains

  1. Airflow Model Testing to Determine the Distribution of Hot Gas Flow and O/F Ratio Across the Space Shuttle Main Engine Main Injector Assembly

    NASA Technical Reports Server (NTRS)

    Mahorter, L.; Chik, J.; McDaniels, D.; Dill, C.

    1990-01-01

    Engine 0209, the certification engine for the new Phase 2+ Hot Gas Manifold (HGM), showed severe deterioration of the Main Combustion Chamber (MCC) liner during hot fire tests. One theory on the cause of the damage held that uneven local distribution of the fuel rich hot gas flow through the main injector assembly was producing regions of high oxidizer/fuel (O/F) ratio near the wall of the MCC liner. Airflow testing was proposed to measure the local hot gas flow rates through individual injector elements. The airflow tests were conducted using full scale, geometrically correct models of both the current Phase 2 and the new Phase 2+ HGMs. Different main injector flow shield configurations were tested for each HGM to ascertain their effect on the pressure levels and distribution of hot gas flow. Instrumentation located on the primary faceplate of the main injector measured hot gas flow through selected injector elements. These data were combined with information from the current space shuttle main engine (SSME) power balances to produce maps of pressure, hot gas flow rate, and O/F ratio near the main injector primary plate. The O/F distributions were compared for the different injector and HGM configurations.

  2. Wireless Self-powered Visual and NDE Robotic Inspection System for Live Gas Distribution Mains

    SciTech Connect

    Susan Burkett; Hagen Schempf

    2006-01-31

    Carnegie Mellon University (CMU) under contract from Department of Energy/National Energy Technology Laboratory (DoE/NETL) and co-funding from the Northeast Gas Association (NGA), has completed the overall system design of the next-generation Explorer-II (X-II) live gas main NDE and visual inspection robot platform. The design is based on the Explorer-I prototype which was built and field-tested under a prior (also DoE- and NGA co-funded) program, and served as the validation that self-powered robots under wireless control could access and navigate live natural gas distribution mains. The X-II system design ({approx}8 ft. and 66 lbs.) was heavily based on the X-I design, yet was substantially expanded to allow the addition of NDE sensor systems (while retaining its visual inspection capability), making it a modular system, and expanding its ability to operate at pressures up to 750 psig (high-pressure and unpiggable steel-pipe distribution mains). A new electronics architecture and on-board software kernel were added to again improve system performance. A locating sonde system was integrated to allow for absolute position-referencing during inspection (coupled with external differential GPS) and emergency-locating. The power system was upgraded to utilize lithium-based battery-cells for an increase in mission-time. The system architecture now relies on a dual set of end camera-modules to house the 32-bit processors (Single-Board Computer or SBC) as well as the imaging and wireless (off-board) and CAN-based (on-board) communication hardware and software systems (as well as the sonde-coil and -electronics). The drive-module (2 ea.) are still responsible for bracing (and centering) to drive in push/pull fashion the robot train into and through the pipes and obstacles. The steering modules and their arrangement, still allow the robot to configure itself to perform any-angle (up to 90 deg) turns in any orientation (incl. vertical), and enable the live launching and

  3. Vector magnetometry sensor for internal inspection of gas distribution mains. Final report, February 1995-August 1996

    SciTech Connect

    Farra, R.; Fowler, T.

    1997-06-01

    There is a recognized need for an advanced distribution pipe inspection system which can operate in 4` and 6` diameter pipes. This program developed a prototype sensor car based on vector magnetometry. The prototype sensor system was tested in the laboratory. Test data is presented showing defect detection capability for defects as small as 25% of the pipe wall. Field tests were also conducted with mixed results. Varying corrosion levels were observed. However, specific defects were difficult to identify.

  4. Explorer-II: Wireless Self-Powered Visual and NDE Robotic Inspection System for Live Gas Distribution Mains

    SciTech Connect

    Carnegie Mellon University

    2008-09-30

    Carnegie Mellon University (CMU) under contract from Department of Energy/National Energy Technology Laboratory (DoE/NETL) and co-funding from the Northeast Gas Association (NGA), has completed the overall system design, field-trial and Magnetic Flux Leakage (MFL) sensor evaluation program for the next-generation Explorer-II (X-II) live gas main Non-destructive Evaluation (NDE) and visual inspection robot platform. The design is based on the Explorer-I prototype which was built and field-tested under a prior (also DoE- and NGA co-funded) program, and served as the validation that self-powered robots under wireless control could access and navigate live natural gas distribution mains. The X-II system design ({approx}8 ft. and 66 lbs.) was heavily based on the X-I design, yet was substantially expanded to allow the addition of NDE sensor systems (while retaining its visual inspection capability), making it a modular system, and expanding its ability to operate at pressures up to 750 psig (high-pressure and unpiggable steel-pipe distribution mains). A new electronics architecture and on-board software kernel were added to again improve system performance. A locating sonde system was integrated to allow for absolute position-referencing during inspection (coupled with external differential GPS) and emergency-locating. The power system was upgraded to utilize lithium-based battery-cells for an increase in mission-time. The resulting robot-train system with CAD renderings of the individual modules. The system architecture now relies on a dual set of end camera-modules to house the 32-bit processors (Single-Board Computer or SBC) as well as the imaging and wireless (off-board) and CAN-based (on-board) communication hardware and software systems (as well as the sonde-coil and -electronics). The drive-module (2 ea.) are still responsible for bracing (and centering) to drive in push/pull fashion the robot train into and through the pipes and obstacles. The steering modules

  5. Overview of gas distribution

    SciTech Connect

    Long, G.M.

    1989-01-01

    The purpose of this paper is to present a concise overview of the nature of a natural gas distribution utility. To this end, gas distribution'' is defined, then the functions performed while distributing natural gas are discussed. Topics presented include: franchise; planning (layouts, load estimation, sizing, system supply points, and storage considerations); design (codes/standards, materials, corrosion mitigation considerations, valves and fittings, vaults and stations, and main routing); construction (work force, sequencing, testing, purge and tie-in, and setting meters); operations (gas dispatching, customer service,and maintenance); continuity of supply; and sales and marketing. The paper concludes with discussion of converting an existing manufactured gas system over to natural gas. 4 refs., 6 figs.

  6. Automated Gas Distribution System

    NASA Astrophysics Data System (ADS)

    Starke, Allen; Clark, Henry

    2012-10-01

    The cyclotron of Texas A&M University is one of the few and prized cyclotrons in the country. Behind the scenes of the cyclotron is a confusing, and dangerous setup of the ion sources that supplies the cyclotron with particles for acceleration. To use this machine there is a time consuming, and even wasteful step by step process of switching gases, purging, and other important features that must be done manually to keep the system functioning properly, while also trying to maintain the safety of the working environment. Developing a new gas distribution system to the ion source prevents many of the problems generated by the older manually setup process. This developed system can be controlled manually in an easier fashion than before, but like most of the technology and machines in the cyclotron now, is mainly operated based on software programming developed through graphical coding environment Labview. The automated gas distribution system provides multi-ports for a selection of different gases to decrease the amount of gas wasted through switching gases, and a port for the vacuum to decrease the amount of time spent purging the manifold. The Labview software makes the operation of the cyclotron and ion sources easier, and safer for anyone to use.

  7. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf, Ph.D.

    2003-02-27

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. A prototype system was built for low-pressure cast-iron mains and tested in a spider- and serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The prototype unit combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-slave architecture to collect data from a distributed spider-arrangement, and in a master-repeater-slave configuration in serial or ladder-network arrangements. It was found that the system was capable of performing all data-sampling and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and valuable data was collected in order to determine how to improve on range and data-quality in the future.

  8. Gas Main Sensor and Communications Network System

    SciTech Connect

    Hagen Schempf

    2006-05-31

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the Northeast Gas Association (NGA), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. This projected was completed in April 2006, and culminated in the installation of more than 2 dozen GasNet nodes in both low- and high-pressure cast-iron and steel mains owned by multiple utilities in the northeastern US. Utilities are currently logging data (off-line) and monitoring data in real time from single and multiple networked sensors over cellular networks and collecting data using wireless bluetooth PDA systems. The system was designed to be modular, using in-pipe sensor-wands capable of measuring, flow, pressure, temperature, water-content and vibration. Internal antennae allowed for the use of the pipe-internals as a waveguide for setting up a sensor network to collect data from multiple nodes simultaneously. Sensor nodes were designed to be installed with low- and no-blow techniques and tools. Using a multi-drop bus technique with a custom protocol, all electronics were designed to be buriable and allow for on-board data-collection (SD-card), wireless relaying and cellular network forwarding. Installation options afforded by the design included direct-burial and external polemounted variants. Power was provided by one or more batteries, direct AC-power (Class I Div.2) and solar-array. The utilities are currently in a data-collection phase and intend to use the collected (and processed) data to make capital improvement decisions, compare it to Stoner model predictions and evaluate the use of such a system for future expansion, technology-improvement and commercialization starting later in 2006.

  9. GAS MAIN SENSOR AND COMMUNICATIONS NETWORK SYSTEM

    SciTech Connect

    Hagen Schempf

    2004-09-30

    Automatika, Inc. was contracted by the Department of Energy (DOE) and with co-funding from the New York Gas Group (NYGAS), to develop an in-pipe natural gas prototype measurement and wireless communications system for assessing and monitoring distribution networks. In Phase II of this three-phase program, an improved prototype system was built for low-pressure cast-iron and high-pressure steel (including a no-blow installation system) mains and tested in a serial-network configuration in a live network in Long Island with the support of Keyspan Energy, Inc. The experiment was carried out in several open-hole excavations over a multi-day period. The prototype units (3 total) combined sensors capable of monitoring pressure, flow, humidity, temperature and vibration, which were sampled and combined in data-packages in an in-pipe master-repeater-slave configuration in serial or ladder-network arrangements. It was verified that the system was capable of performing all data-sampling, data-storage and collection as expected, yielding interesting results as to flow-dynamics and vibration-detection. Wireless in-pipe communications were shown to be feasible and the system was demonstrated to run off in-ground battery- and above-ground solar power. The remote datalogger access and storage-card features were demonstrated and used to log and post-process system data. Real-time data-display on an updated Phase-I GUI was used for in-field demonstration and troubleshooting.

  10. Distributed PV Adoption in Maine Through 2021

    SciTech Connect

    Gagnon, Pieter; Sigrin, Ben

    2015-11-06

    NREL has used its dSolar (distributed solar) model to generate low-medium-high estimates of distributed PV adoption in Maine through 2021. This presentation gives a high-level overview of the model and modeling results.

  11. Soil gas distribution in the main coseismic surface rupture zone of the 1980, Ms = 6.9, Irpinia earthquake (southern Italy)

    NASA Astrophysics Data System (ADS)

    Ciotoli, Giancarlo; Bigi, Sabina; Tartarello, Chiara; Sacco, Pietro; Lombardi, Salvatore; Ascione, Alessandra; Mazzoli, Stefano

    2014-03-01

    Soil gas measurements of different gas species with different geochemical behaviors were performed in the area of the Pecore Plain, a 200 m × 300 m sized, fault-bounded extensional basin located in the northern Mount Marzano massif, in the axial belt of the southern Apennine chain. The Pecore Plain area was affected by coseismic surface faulting during the Ms = 6.9, 1980 Irpinia earthquake, the strongest and most destructive seismic event of the last 30 years in southern Italy. The collected data and their geostatistical analysis provide new insights into the control exerted by active fault segments on deep-seated gas migration toward the surface. The results define anomalies that are aligned with the NW-SE trending coseismic rupture of the 1980 earthquake along the western border of the plain, as well as along the southern border of the plain where a hidden, E-W striking fault is inferred. Geospatial analysis highlights an anisotropic spatial behavior of 222Rn along the main NW-SE trend and of CO2 along the E-W trend. This feature suggests a correlation between the shape and orientation of the anomalies and the barrier/conduit behavior of fault zones in the area. Furthermore, our results show that gas migration through brittle deformation zones occurs by advective processes, as suggested by the relatively high migration rate needed to obtain anomalies of short-lived 222Rn in the soil pores.

  12. Multiple complementary gas distribution assemblies

    DOEpatents

    Ng, Tuoh-Bin; Melnik, Yuriy; Pang, Lily L; Tuncel, Eda; Nguyen, Son T; Chen, Lu

    2016-04-05

    In one embodiment, an apparatus includes a first gas distribution assembly that includes a first gas passage for introducing a first process gas into a second gas passage that introduces the first process gas into a processing chamber and a second gas distribution assembly that includes a third gas passage for introducing a second process gas into a fourth gas passage that introduces the second process gas into the processing chamber. The first and second gas distribution assemblies are each adapted to be coupled to at least one chamber wall of the processing chamber. The first gas passage is shaped as a first ring positioned within the processing chamber above the second gas passage that is shaped as a second ring positioned within the processing chamber. The gas distribution assemblies may be designed to have complementary characteristic radial film growth rate profiles.

  13. Eccentricity distribution in the main asteroid belt

    NASA Astrophysics Data System (ADS)

    Malhotra, Renu; Wang, Xianyu

    2017-03-01

    The observationally complete sample of the main belt asteroids now spans more than two orders of magnitude in size and numbers more than 64 000 (excluding collisional family members). We undertook an analysis of asteroids' eccentricities and their interpretation with simple physical models. We find that a century old conclusion that the asteroids' eccentricities follow a Rayleigh distribution holds for the osculating eccentricities of large asteroids, but the proper eccentricities deviate from a Rayleigh distribution; there is a deficit of eccentricities smaller than ∼0.1 and an excess of larger eccentricities. We further find that the proper eccentricities do not depend significantly on asteroid size but have strong dependence on heliocentric distance; the outer asteroid belt follows a Rayleigh distribution, but the inner belt is strikingly different. Eccentricities in the inner belt can be modelled as a vector sum of a primordial eccentricity vector of random orientation and magnitude drawn from a Rayleigh distribution of parameter ∼0.06, and an excitation of random phase and magnitude ∼0.13. These results imply that when a late dynamical excitation of the asteroids occurred, it was independent of asteroid size and was stronger in the inner belt than in the outer belt. We discuss implications for the primordial asteroid belt and suggest that the observationally complete sample size of main belt asteroids is large enough that more sophisticated model-fitting of the eccentricities is warranted and could serve to test alternative theoretical models of the dynamical excitation history of asteroids and its links to the migration history of the giant planets.

  14. Gas distribution safety development plan

    SciTech Connect

    Drake, E.M.; Richardson, D.L.; Long, M.H.

    1981-12-01

    To identify the safety research needs of the gas distribution industry, ADL analysts reviewed recently completed and ongoing research projects related to gas distribution system safety, both in the US and abroad, compiled a list of existing projects that should be continued and 11 new projects that the Gas Research Institute should begin, and developed a method for ranking the importance of the projects elected for funding. GRI's current program satisfies most of the identified safety research needs.

  15. 34. ROUGH GAS MAIN RUNNING SOUTHEAST FROM THE BOP SHOP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    34. ROUGH GAS MAIN RUNNING SOUTHEAST FROM THE BOP SHOP TO THE DUAL VENTURI GAS WASHERS. - U.S. Steel Duquesne Works, Basic Oxygen Steelmaking Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  16. 14. DETAIL OF CLEAN GAS MAIN (UPPER PIPE) AND ROUGH ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. DETAIL OF CLEAN GAS MAIN (UPPER PIPE) AND ROUGH GAS MAIN FOR BLAST FURNACE No. 2 AT THE BASE OF HOT BLAST STOVES LOOKING EAST. (Jet Lowe) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  17. 51. View looking west down ladle car rightofway; gas main ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    51. View looking west down ladle car right-of-way; gas main at right, Babcock & Wilcox boilers at left. - Sloss-Sheffield Steel & Iron, First Avenue North Viaduct at Thirty-second Street, Birmingham, Jefferson County, AL

  18. Catalogue of the main gas manifestation of Greece: Geochemical characterisation and preliminary gas hazard assessment

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Walter; Kyriakopoulos, Konstantinos; Calabrese, Sergio

    2014-05-01

    Like other geodynamically active areas, the Hellenic territory is also affected by a large number of geogenic gas manifestations. These occur either in form of point sources (fumaroles, mofettes, bubbling gases) or as diffuse soil gas emanations. The present work produced a first catalogue of the geogenic gas manifestations of the whole Hellenic territory also considering a few literature data. All collected samples were analysed for their chemical composition (He, Ne, Ar, O2, N2, H2, H2S, CO, CH4 and CO2) and isotopic composition (He, CO2-C, CH4-C, N2-N). Geogenic sources release huge amounts of gases, which, apart from having important influences on the global climate, could have strong impact on human health. Gases have both acute and chronic effects. Carbon Dioxide and Hydrogen Sulphide are the main gases responsible for acute mortality due to their asphyxiating and/or toxic properties. Methane instead represents a risk for its explosive properties. Gas hazard is often disregarded because in fatal episodes connected to geogenic gases the death cause is often not correctly attributed. Due to the fact that geodynamic active areas can release geogenic gases for million years over wide areas, it is important not to underestimate potential risks. A preliminary estimation of the gas hazard has been made for the time period of the last 20 years considering the whole population of Greece. In this period at least two fatal episodes with a total of three victims could be certainly attributed to geogenic gases (specifically CO2). This would give a risk of 1.3×10-8 fatality from geogenic gas manifestations per annum. Such value, although probably underestimated, is much lower than most other natural or anthropogenic risks. Nevertheless this risk, being unevenly distributed along the whole territory, should not be overlooked especially in areas with high density of gas manifestations and high soil gas fluxes.

  19. Air and gas pockets in sewerage pressure mains.

    PubMed

    Lubbers, C L; Clemens, F

    2005-01-01

    In The Netherlands, wastewater is collected in municipal areas and transported to large centralised WWTPs by means of an extensive system of pressure mains. Over the past decades these pressure mains did not receive much attention in terms of monitoring of performance or maintenance. For that reason, in practice their state of functioning is often not known. Failure of operation is only noticed when the capacity of the system proves to be insufficient to fulfil the minimum design capacity demand. A recent inventory showed that half of the pressure mains show an increased pressure loss for no directly obvious reason. Many causes may account for the reduction of the system's nominal capacity like an increased wall roughness, scaling or occurrence of free gas in the pipeline. The occurrence of free gas may be caused by degassing of dissolved (bio) gas or by air entrained at the pumps' inlet or at air valves. A research study is started that will focus on three main issues: The description of the gas-water phenomena in wastewater pressure mains with respect to transportation and dynamic hydraulic behaviour, A method to diagnose gas problems, and To overcome future problems by either applying remedial measures or improving the design of wastewater pressure systems. For this study, two experimental facilities are constructed, a small circuit for the study of multi-phase flow and a second, larger one for the research into diagnostic methods. This paper describes the preliminary results of the experiments in the multi-phase circuit.

  20. MEASUREMENT OF METHANE EMISSIONS FROM UNDERGROUND DISTRIBUTION MAINS AND SERVICES

    EPA Science Inventory

    The paper reports results of measurements of methane emissions from underground distribution mains and services. In the program, leakage from underground distribution systems is estimated by combining leak measurements with historical leak record data and the length of undergroun...

  1. On the spatial distribution of main belt asteroids

    NASA Astrophysics Data System (ADS)

    Souami, D.; Lemaitre, A.; Souchay, J.

    2014-12-01

    We investigate here the distribution of main belt asteroids in the space with respect to the ecliptic-equinox J2000. We identify and confirm a sinusoidal behaviour of this distribution, which disappears when the inclination is given with respect to Jupiter's orbital plane, or with respect to the invariable plane (IP). This behaviour is explained by planetary secular effects, mainly due to Jupiter. Furthermore, we identify three different orbital behaviours that explain the density distribution in this space.

  2. Gas pockets in a wastewater rising main: a case study.

    PubMed

    Pozos-Estrada, Oscar; Fuentes-Mariles, Oscar A; Pozos-Estrada, Adrian

    2012-01-01

    This paper presents a case study of an existing wastewater rising main (WWRM) in which an extreme transient event produced by simultaneous power failure of the pumps caused the rupture of a 1.2 m (48 in) prestressed concrete cylinder pipe (PCCP), causing an important leakage of sewage. The event and the methodology followed in order to validate the diagnostics of the failure are described. The detail study included in situ observation of the system, experimental investigation in a setup, hydraulic analysis, as well as details of the structural strength of the WWRM. After the extensive investigation and several simulations of fluid transients for different scenarios and flow conditions, it was found that stationary small gas pockets accumulated at high points of the WWRM were identified as the principal contributory factor of the failure. This case study serves as clear warning of the consequences of operating a WWRM with gas pockets at its high points.

  3. 46 CFR 169.678 - Main distribution panels and switchboards.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Main distribution panels and switchboards. 169.678 Section 169.678 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Machinery and Electrical Electrical Installations Operating at Potentials of 50 Volts...

  4. The Size Frequency Distribution of Small Main-Belt Asteroids

    NASA Technical Reports Server (NTRS)

    Burt, Brian J.; Trilling, David E.; Hines, Dean C.; Stapelfeldt, Karl R.; Rebull, Luisa M.; Fuentes, Cesar I.; Hulsebus, Alan

    2012-01-01

    The asteroid size distribution informs us about the formation and composition of the Solar System. We build on our previous work in which we harvest serendipitously observed data of the Taurus region and measure the brightness and size distributions of Main-belt asteroids. This is accomplished with the highly sensitive MIPS 24 micron channel. We expect to catalog 104 asteroids, giving us a statistically significant data set. Results from this investigation will allow us to characterize the total population of small, Main-belt asteroids. Here we will present new results on the completeness of our study; on the presence of size distribution variations with inclination and radial distance in the belt; and early result on other archival fields.

  5. The fossilized size distribution of the main asteroid belt

    NASA Astrophysics Data System (ADS)

    Bottke, William F.; Durda, Daniel D.; Nesvorný, David; Jedicke, Robert; Morbidelli, Alessandro; Vokrouhlický, David; Levison, Hal

    2005-05-01

    Planet formation models suggest the primordial main belt experienced a short but intense period of collisional evolution shortly after the formation of planetary embryos. This period is believed to have lasted until Jupiter reached its full size, when dynamical processes (e.g., sweeping resonances, excitation via planetary embryos) ejected most planetesimals from the main belt zone. The few planetesimals left behind continued to undergo comminution at a reduced rate until the present day. We investigated how this scenario affects the main belt size distribution over Solar System history using a collisional evolution model (CoEM) that accounts for these events. CoEM does not explicitly include results from dynamical models, but instead treats the unknown size of the primordial main belt and the nature/timing of its dynamical depletion using innovative but approximate methods. Model constraints were provided by the observed size frequency distribution of the asteroid belt, the observed population of asteroid families, the cratered surface of differentiated Asteroid (4) Vesta, and the relatively constant crater production rate of the Earth and Moon over the last 3 Gyr. Using CoEM, we solved for both the shape of the initial main belt size distribution after accretion and the asteroid disruption scaling law QD∗. In contrast to previous efforts, we find our derived QD∗ function is very similar to results produced by numerical hydrocode simulations of asteroid impacts. Our best fit results suggest the asteroid belt experienced as much comminution over its early history as it has since it reached its low-mass state approximately 3.9-4.5 Ga. These results suggest the main belt's wavy-shaped size-frequency distribution is a "fossil" from this violent early epoch. We find that most diameter D≳120 km asteroids are primordial, with their physical properties likely determined during the accretion epoch. Conversely, most smaller asteroids are byproducts of fragmentation

  6. Sampling and quantifying invertebrates from drinking water distribution mains.

    PubMed

    van Lieverloo, J Hein M; Bosboom, Dick W; Bakker, Geo L; Brouwer, Anke J; Voogt, Remko; De Roos, Josje E M

    2004-03-01

    Water utilities in the Netherlands aim at controlling the multiplication of (micro-) organisms by distributing biologically stable water through biologically stable materials. Disinfectant residuals are absent or very low. To be able to assess invertebrate abundance, methods for sampling and quantifying these animals from distribution mains were optimised and evaluated. The presented method for collecting invertebrates consists of unidirectionally flushing a mains section with a flow rate of 1 ms(-1) and filtering the flushed water in two separate flows with 500 microm and 100 microm mesh plankton gauze filters. Removal efficiency from mains was evaluated in nine experiments by collecting the invertebrates removed from the mains section by intensive cleaning immediately subsequent to sampling. Of 12 taxa distinguished, all except case-building Chironomidae larvae (2%) and Oligochaeta (30%) were removed well (51-75%). Retention of invertebrates in 100 microm filters was evaluated by filtering 39 filtrates using 30 microm filters. Except for flexible and small invertebrates such as Turbellaria (13%), Nematoda (11%) and Copepoda larvae (24%), most taxa were well retained in the 100 microm filters (53-100%). During sample processing, the method for taking sub-samples with a 10 ml pipette from the suspension of samples with high sediment concentrations was found to perform well in 75% of the samples. During a 2-year national survey in the Netherlands and consecutive investigations, the method appeared to be very suitable to assess the abundance of most invertebrate taxa in drinking water distribution systems and to be practicable for relatively inexperienced sampling and lab technicians. Although the numbers of small, less abundant or sessile taxa were not accurately assessed using the method, these taxa probably should not be the primary focus of monitoring by water utilities, as consumer complaints are not likely to be caused by these invertebrates. The accuracy of

  7. Distribution of the main malaria vectors in Kenya

    PubMed Central

    2010-01-01

    Background A detailed knowledge of the distribution of the main Anopheles malaria vectors in Kenya should guide national vector control strategies. However, contemporary spatial distributions of the locally dominant Anopheles vectors including Anopheles gambiae, Anopheles arabiensis, Anopheles merus, Anopheles funestus, Anopheles pharoensis and Anopheles nili are lacking. The methods and approaches used to assemble contemporary available data on the present distribution of the dominant malaria vectors in Kenya are presented here. Method Primary empirical data from published and unpublished sources were identified for the period 1990 to 2009. Details recorded for each source included the first author, year of publication, report type, survey location name, month and year of survey, the main Anopheles species reported as present and the sampling and identification methods used. Survey locations were geo-positioned using national digital place name archives and on-line geo-referencing resources. The geo-located species-presence data were displayed and described administratively, using first-level administrative units (province), and biologically, based on the predicted spatial margins of Plasmodium falciparum transmission intensity in Kenya for the year 2009. Each geo-located survey site was assigned an urban or rural classification and attributed an altitude value. Results A total of 498 spatially unique descriptions of Anopheles vector species across Kenya sampled between 1990 and 2009 were identified, 53% were obtained from published sources and further communications with authors. More than half (54%) of the sites surveyed were investigated since 2005. A total of 174 sites reported the presence of An. gambiae complex without identification of sibling species. Anopheles arabiensis and An. funestus were the most widely reported at 244 and 265 spatially unique sites respectively with the former showing the most ubiquitous distribution nationally. Anopheles gambiae

  8. Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

    NASA Technical Reports Server (NTRS)

    Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

    1995-01-01

    Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn-around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

  9. Flow Distribution Around the SSME Main Injector Assembly Using Porosity Formulation

    NASA Technical Reports Server (NTRS)

    Cheng, Gary C.; Chen, Yen-Sen; Wang, Ten-See

    1995-01-01

    Hot gas turbulent flow distribution around the main injector assembly of the Space Shuttle Main Engine (SSME) and Liquid Oxidizer (LOX) flow distribution through the LOX posts have a great effect on the combustion phenomena inside the main combustion chamber. In order to design a CFD model to be an effective engineering analysis tool with good computational turn- around time (especially for 3-D flow problems) and still maintain good accuracy in describing the flow features, the concept of porosity was employed to describe the effects of blockage and drag force due to the presence of the LOX posts in the turbulent flow field around the main injector assembly of the SSME. 2-D numerical studies were conducted to identify the drag coefficients of the flows both through tube banks and around the shielded posts over a wide range of Reynolds numbers. Empirical, analytical expressions of the drag coefficient as a function of local flow Reynolds number were then deduced. The porosity model was applied to the turbulent flow around the main injector assembly of the SSME, and analyses were performed. The 3-D CFD analysis was divided into three parts, LOX dome, hot gas injector assembly, and hydrogen cavity. The numerical results indicate that the mixture ratio at the downstream of injector face was close to stoichiometric around baffle elements.

  10. Radon gas distribution in natural gas processing facilities and workplace air environment.

    PubMed

    Al-Masri, M S; Shwiekani, R

    2008-04-01

    Evaluation was made of the distribution of radon gas and radiation exposure rates in the four main natural gas treatment facilities in Syria. The results showed that radiation exposure rates at contact of all equipment were within the natural levels (0.09-0.1 microSvh(-1)) except for the reflex pumps where a dose rate value of 3 microSvh(-1) was recorded. Radon concentrations in Syrian natural gas varied between 15.4 Bq m(-3) and 1141 Bq m(-3); natural gas associated with oil production was found to contain higher concentrations than the non-associated natural gas. In addition, radon concentrations were higher in the central processing facilities than the wellheads; these high levels are due to pressurizing and concentrating processes that enhance radon gas and its decay products. Moreover, the lowest 222Rn concentration was in the natural gas fraction used for producing sulfur; a value of 80 Bq m(-3) was observed. On the other hand, maximum radon gas and its decay product concentrations in workplace air environments were found to be relatively high in the gas analysis laboratories; a value of 458 Bq m(-3) was observed. However, all reported levels in the workplaces in the four main stations were below the action level set by IAEA for chronic exposure situations involving radon, which is 1000 Bq m(-3).

  11. Sour gas distribution in the Amudaria Basin, Central Asia

    SciTech Connect

    Marina, D.; Ivlev, A.; Shkutnik, E.

    1995-08-01

    The Amudaria Basin is the main sour-gas bearing region in Central Asia. In this region, sour gases occur in Upper Jurassic carbonate-reservoir rocks as well as in terrigenous rocks of Cretareous age, but the Upper Jurassic sulfate-carbonate complex is the main sour-gas bearing and producing complex. The chemical and isotopic composition of fluids in Upper Jurassic rocks show that sulfate reduction is the main process responsible for sour gas formation in the central part of the basin, where Kimmeridgian-Tithonian evaporites occur. The H{sub 2}S content of gases varies widely (0 to 10 percent by volume), even within similar carbonate traps located close to one another in the same temperature zone. Analyses of sour-gas distribution and composition in fluids in these areas indicate the main factors which control the variation of H{sub 2}S content in Upper Jurassic hydrocarbon pools in the same temperature zones. These factors include (1) the carbonate sediment facies type (shelf, barrier reef, deep water facies), and (2) within the same facies, the characteristics of traps and pools (tight, gentle, structural, phase-type, etc). The most favorable conditions for H{sub 2}S accumulation occur in hydrocarbon pools confined to the barrier reef flat and the parts of the shelf closest to it. The least favorable conditions are in pools confined to local reefs or carbonate build-ups located within the deep-water facies zone. These results are important for the prediction of H{sub 2}S in hydrocarbon pools. In most cases, H{sub 2}S in the Cretaceous complex is epigenetic. With the exception of Central Karakum zone H{sub 2}S distribution in this complex depends on the distribution and composition of Upper Jurassic evaporites.

  12. Gas distribution and starbursts in shell galaxies

    NASA Technical Reports Server (NTRS)

    Weil, Melinda L.; Hernquist, Lars

    1993-01-01

    Detailed maps of most elliptical galaxies reveal that, whereas the greatest part of their luminous mass originates from a smooth distribution with a surface brightness approximated by a de Vaucouleurs law, a small percentage of their light is contributed by low surface brightness distortions termed 'fine structures'. The sharp-edged features called 'shells' are successfully reproduced by merger and infall models involving accretion from less massive companions. In this context, dwarf spheroidal and compact disk galaxies are likely progenitors of these stellar phenomena. However, it is probable that the sources of shell-forming material also contain significant amounts of gas. This component may play an important role in constraining the formation and evolution of shell galaxies. To investigate the effects of the gaseous component, numerical simulations were performed to study the tidal disruption of dwarf galaxies containing both gas and stars by more massive primaries, and the evolution of the ensuing debris. The calculations were performed with a hybrid N-body/hydrodynamics code. Collisionless matter is evolved using a conventional N-body technique and gas is treated using smoothed particle hydrodynamics in which self-gravitating fluid elements are represented as particles evolving according to Lagrangian hydrodynamic equations. An isothermal equation of state is employed so the gas remains at a temperature 104 K. Owing to the large mass ratio between the primary and companion, the primary is modeled as a rigid potential and the self-gravity of both galaxies is neglected.

  13. A Frequency Model of Vibrational Processes in Gas-Turbine Drives of Compressor Stations of Main Gas Pipelines

    NASA Astrophysics Data System (ADS)

    Chekardovskiy, M. N.; Chekardovskiy, S. M.; Razboynikov, A. A.; Ponomareva, T. G.

    2016-10-01

    At compressor stations, systematic measurements of noise and vibration of power equipment - gas compressor units - are carried out. The article presents basic equations for calculating natural and forced frequencies at which the main defects appear. According to the studied dependences, results of calculations are obtained on the following types of drives for gas-compressor units GTK-10-4, Avon-1534, DG-90.

  14. Condition Assessment for Drinking Water Transmission and Distribution Mains

    EPA Science Inventory

    This project seeks to improve the capability to characterize the condition of water infrastructure. The integrity of buried drinking water mains is critical, as it influences water quality, losses, pressure and cost. This research complements the U.S. Environmental Protection A...

  15. Reconstructing the spin distributions of main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Holsapple, K.

    2014-07-01

    INTRODUCTION: We now have spin data for almost six thousand asteroids, each value being a result of that asteroid's history. Some features of that distribution are now evident. The gravity spin limit at the period of about 2.3 h for asteroids with a diameter greater than a few kilometers is well established (Harris 1996, Pravec and Harris 2000, Holsapple 2001, and others). The strength of smaller asteroids as inferred from the ''fast spinners'' has been presented by Holsapple (2007), Sanchez and Scheeres (2014), and others. Several statistical analyses of the database have been presented (e.g., Pravec and Harris 2002). Here that database is used as a means of investigating the prior history of the asteroid belt. THEORETICAL APPROACHES: A way to understand the data is to attempt to reproduce it using theoretical models and numerical simulations of the physics of the processes that created it. Such studies have evolved since McAdoo and Burns (1973) first suggested collisions as a source of the spins; they include Davis et al. (1979), Dobrovolskis and Burns (1984), Harris (1979), Davis et al. (1989), Farinella et al. (1992), Henych and Pravec (2013), and others. These analyses are based upon averaging the effects of a number of individual impacts into a given target asteroid. I retrace the path and analyses of those authors in this work, but make important modifications and updates. The primary elements introduced in those prior studies include: 1) a population of asteroids in a given space; 2) a distribution of impact velocities and angles; 3) the efficiency of angular-momentum transfer in an impact; 4) the loss or gain of mass and angular inertia; 5) the amount, direction, and speed of the cratering ejecta. The characteristics of the ejecta are especially important: they determine the ''angular-momentum drain'' first identified by Dobrovolskis and Burns (1984). It is caused by the preferential escape of ejecta in the downrange spin direction. Here I revisit, update

  16. Preliminary analysis of selected gas dynamic problems. [space shuttle main engine main combustion transients and IUS nozzle flow

    NASA Technical Reports Server (NTRS)

    Prozan, R. J.; Farmer, R. C.

    1985-01-01

    The VAST computer code was used to analyze SSME main combustion chamber start-up transients and the IUS flow field for a damaged nozzle was investigated to better understand the gas dynamic considerations involved in vehicle problems, the effect of start transients on the nozzle flow field for the SSME, and the possibility that a damaged nozzle could account for the acceleration anomaly noted on IUS burn. The results obtained were compared with a method of characteristics prediction. Pressure solutions from both codes were in very good agreement and the Mach number solution on the nozzle centerline deviates substantially for the high expansions for the SSME. Since this deviation was unexpected, the phenomenon is being further examined.

  17. Karst hazard assessment in the design of the main gas pipeline (South Yakutia)

    NASA Astrophysics Data System (ADS)

    Strokova, L. A.; Dutova, E. M.; Ermolaeva, A. V.; Alimova, I. N.; Strelnikova, A. B.

    2015-11-01

    The paper represents the description of the zonal and regional geological factors of geoengineering conditions which characterize the territory in South Yakutia crossed by the designed main gas pipeline. Cryogenic processes and karst are considered to be the most dangerous hazards for gas pipeline maintenance. Karst hazard assessment of the gas pipeline section made in the course of the research has involved a complex of geological methods: geoengineering, geophysical, hydrogeological, and mapping. Sections prone to karst development have been identified. The authors have suggested the measures to protect potentially hazardous sections and to ensure timely informing on sinkhole collapses.

  18. Powder Size and Distribution in Ultrasonic Gas Atomization

    NASA Astrophysics Data System (ADS)

    Rai, G.; Lavernia, E.; Grant, N. J.

    1985-08-01

    Ultrasonic gas atomization (USGA) produces powder sizes dependent on the ratio of the nozzle jet diameter to the distance of spread dt/R, Powder size distribution is attributed to the spread of atomizing gas jets during travel from the nozzle exit to the metal stream. The spread diminishes at higher gas atomization pressures. In this paper, calculated powder sizes and distribution are compared with experimentally determined values.

  19. 157. ARAIII Reactor building (ARA608) Main gas loop mechanical flow ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    157. ARA-III Reactor building (ARA-608) Main gas loop mechanical flow sheet. This drawing was selected as a typical example of mechanical arrangements within reactor building. Aerojet-general 880-area/GCRE-0608-50-013-102634. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  20. Detection of gas pockets in pressurised wastewater mains using dynamic system response analysis.

    PubMed

    Lubbers, C; Clemens, F

    2007-01-01

    In the Netherlands, wastewater is mostly collected in combined sewer system and transported to a WWTP through pressure mains. These pressure mains form an element of the system that did not receive much attention lately with respect to monitoring of performance and maintenance. For that reason, their state of functioning is often not known. Failure of operation is only noticed when during storm conditions the capacity of the system drops, resulting in undesirable discharge to the surface water. A recently made inventory showed that about half of the pressure mains show increased pressure loss for no obvious reason. Reduction of the systems nominal capacity can result from many causes, like increased wall roughness, scaling and the occurrence of free gas in the pipeline. The occurrence of gas-pockets may be caused by degassing of dissolved gas, but also by air entrapment at the pump inlet or at air valves. A research project is started that will be carried out from 2003 to 2005. This project focuses on three goals: the description of the gas-water transport phenomena in wastewater pressure mains, a method to detect and diagnose gas problems, and to overcome future problems by either applying remedial measures or by developing improved design methods for wastewater pressure systems. This paper describes the layout of the experimental set-up to detect and diagnose gas problems and the first results of the experiments are presented and discussed. The results are used to validate a model (Wanda) developed by Delft Hydraulics that describes the phenomena involved in surges in air/water transport.

  1. Molecular and atomic gas along and across the main sequence of star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Saintonge, Amelie; Catinella, Barbara; Cortese, Luca; Genzel, Reinhard; Giovanelli, Riccardo; Haynes, Martha P.; Janowiecki, Steven; Kramer, Carsten; Lutz, Katharina A.; Schiminovich, David; Tacconi, Linda J.; Wuyts, Stijn; Accurso, Gioacchino

    2016-10-01

    We use spectra from the ALFALFA, GASS and COLD GASS surveys to quantify variations in the mean atomic and molecular gas mass fractions throughout the SFR-M* plane and along the main sequence (MS) of star-forming galaxies. Although galaxies well below the MS tend to be undetected in the Arecibo and IRAM observations, reliable mean atomic and molecular gas fractions can be obtained through a spectral stacking technique. We find that the position of galaxies in the SFR-M* plane can be explained mostly by their global cold gas reservoirs as observed in the H I line, with in addition systematic variations in the molecular-to-atomic ratio and star formation efficiency. When looking at galaxies within ±0.4 dex of the MS, we find that as stellar mass increases, both atomic and molecular gas mass fractions decrease, stellar bulges become more prominent, and the mean stellar ages increase. Both star formation efficiency and molecular-to-atomic ratios vary little for massive MS galaxies, indicating that the flattening of the MS is due to the global decrease of the cold gas reservoirs of galaxies rather than to bottlenecks in the process of converting cold atomic gas to stars.

  2. Subaru Main Belt Asteroid Survey (SMBAS)—Size and color distributions of small main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Yoshida, F.; Nakamura, T.

    2007-06-01

    Since February, 2001, we have been conducting a series of survey observations to investigate the physical property of very small Main Belt Asteroids (sub-km MBAs) using the Subaru prime-focus camera (Suprime-Cam) attached to the 8.2 m Subaru telescope. We call our surveys "SMBAS: Subaru Main-Belt Asteroids Survey". This paper presents the results of the second SMBAS (SMBAS-II) which was performed in October 2001. In SMBAS-II, a˜4.0deg2 sky area near the opposition and near the ecliptic was surveyed with the R- and B-bands. We detected 1838 moving objects up to R˜25mag. In SMBAS-II, we could not determine the exact orbits of the objects, because of the short observational arc of only ˜40min. Instead, we statistically estimated the semi-major axis ( a) of each moving object from its apparent sky-motion vector assuming its circular orbit and then, we used the a's to select MBAs and to estimate their absolute magnitudes ( H). The limiting magnitude of SMBAS-II for MBAs was R˜24.2 mag. It corresponds to H˜20 mag at the outer edge of main belt. Thus, assuming their mean albedos, down to D˜0.3 km of S-type asteroids and 0.6 km of C-type asteroids were detected in SMBAS-II. We found that the slopes ( b) of the cumulative size distribution (CSD) (i.e. N(>D)∝D, D: diameter) for sub-km MBAs ranging from 0.6 to 1 km in diameter is 1.29±0.02. Our b value (1.29) is much shallower than those ( ˜ 1.8) of the Palomer Leiden Survey (PLS) [van Houten, C.J., van Houten, G.I., Herget, P., Gehrels, T., 1970. The Palomar-Leiden survey of faint minor planets. Astr. Astrophys. Suppl. 2, 339-448] and Spacewatch surveys [Jedicke, R., Metcalfe, T.S., 1998. The orbital and absolute magnitude distributions of main belt asteroids. Icarus 131, 245-260.] for larger asteroids ( D>5 km) and almost consistent with that (1.3) of SDSS [Ivezić, Ž., Tabachnik, S., Rafikov, R., Lupton, R.H., Quinn, T., Hammergren, M., Eyer, L., Chu, J., Armstrong, J.C., Fan, X., Finlator, K., Geballe, T

  3. A Navier-Stokes flow simulation of the Space Shuttle Main Engine Hot Gas Manifold

    NASA Technical Reports Server (NTRS)

    Yang, Ruey-Jen; Chang, James L. C.; Kwak, Dochan

    1987-01-01

    Incompressible viscous flow inside the turnaround duct, the fuel bowl, the transfer duct and the racetrack of the Space Shuttle Main Engine (SSME) Hot Gas Manifold (HGM) has been computed using the method of pseudo-compressibility together with an implicit, approximate-factorization algorithm. A multiple-zone method is used to make solution of flows in complex geometries easy. A model which predicts the pressure loading for the shield and the injector post arrangement without solving the complex flow field in the main injector region is proposed. The computed results show good qualitative agreement with experimental data.

  4. The relations between natural gas hydrate distribution and structure on Muli basin Qinghai province

    NASA Astrophysics Data System (ADS)

    Yu, C.; Li, Y.; Lu, Z.; Luo, S.; Qu, C.; Tan, S.; Zhang, P.

    2014-12-01

    The Muli area is located in a depression area which between middle Qilian and south Qilian tectonic elements. The natural gas hydrate stratum belongs the Jurassic series coal formation stratum, the main lithological character clamps the purple mudstone, the siltstone, the fine grain sandstone and the black charcoal mudstone for the green gray. The plutonic metamorphism is primarily deterioration function of the Muli area coal, is advantageous in forming the coal-bed gas. Cretaceous system, the Paleogene System and Neogene System mainly include the fine grain red clastic rock and clay stone. The distribution of Quaternary is widespread. The ice water - proluvial and glacier deposit are primarily depositional mode. The Qilian Montanan Muli permafrost area has the good gas source condition (Youhai Zhu 2006) and rich water resources. It is advantage to forming the natural gas hydrate. The natural gas hydrate is one kind of new latent energy, widely distributes in the mainland marginal sea bottom settlings and land permanent tundra. Through researching the area the structure ,the deposition carries on the analysis and responds the characteristic analysis simulation in the rock physics analysis and the seismic in the foundation, and then the reflected seismic data carried by tectonic analysis processing and the AVO characteristic analysis processing reveal that the research area existence natural gas hydrate (already by drilling confirmation) and the natural gas hydrate distribution and the structure relations is extremely close. In the structure development area, the fault and the crevasse crack growing, the natural gas hydrate distribution characteristic is obvious (this is also confirmed the storing space of natural gas hydrate in this area is mainly crevasse crack). This conclusion also agree with the actual drilling result. The research prove that the distribution of natural gas hydrate in this area is mainly controlled by structure control. The possibility of fault

  5. Leaf gas films, underwater photosynthesis and plant species distributions in a flood gradient.

    PubMed

    Winkel, Anders; Visser, Eric J W; Colmer, Timothy D; Brodersen, Klaus P; Voesenek, Laurentius A C J; Sand-Jensen, Kaj; Pedersen, Ole

    2016-07-01

    Traits for survival during flooding of terrestrial plants include stimulation or inhibition of shoot elongation, aerenchyma formation and efficient gas exchange. Leaf gas films form on superhydrophobic cuticles during submergence and enhance underwater gas exchange. The main hypothesis tested was that the presence of leaf gas films influences the distribution of plant species along a natural flood gradient. We conducted laboratory experiments and field observations on species distributed along a natural flood gradient. We measured presence or absence of leaf gas films and specific leaf area of 95 species. We also measured, gas film retention time during submergence and underwater net photosynthesis and dark respiration of 25 target species. The presence of a leaf gas film was inversely correlated to flood frequency and duration and reached a maximum value of 80% of the species in the rarely flooded locations. This relationship was primarily driven by grasses that all, independently of their field location along the flood gradient, possess gas films when submerged. Although the present study and earlier experiments have shown that leaf gas films enhance gas exchange of submerged plants, the ability of species to form leaf gas films did not show the hypothesized relationship with species composition along the flood gradient.

  6. Recent and historical distributions of Canada lynx in Maine and the Northeast

    USGS Publications Warehouse

    Hoving, C.L.; Joseph, R.A.; Krohn, W.B.

    2003-01-01

    The contiguous United States population of Canada lynx (Lynx canadensis Kerr) is listed as threatened under the federal Endangered Species Act. However, the historic distribution of lynx in the Northeast is poorly understood. We used museum records, bibliographic records, and interviews to reconstruct the past distribution of lynx in Maine, which is at the current southern limit of the species' distribution in the eastern United States. We found a total of 118 records, representing at least 509 lynx in Maine. Lynx were observed throughout Maine, 1833-1912, with the exception of coastal areas. After 1913, lynx were most common in the forests of western and northern Maine, and absent to rare along the coast, but had not returned to southern Maine by 1999. Thirty-nine kittens representing at least 21 litters were distributed throughout northern and western Maine, 1864-1999. Populations apparently fluctuated, and in some years 200-300 lynx were harvested in Maine. Prior to the 1900s, lynx were much more widely distributed in the Northeast, ranging from Pennsylvania north into Quebec. Because Canada lynx have had a long presence in northern New England, and at times were relatively common, this species merits serious consideration in conservation planning in this region.

  7. Distribution of heavy metals from flue gas in algal bioreactor

    NASA Astrophysics Data System (ADS)

    Napan, Katerine

    Flue gas from coal-fired power plants is a major source of CO2 to the atmosphere. Microalgae can use this enriched form of CO2 as carbon source and in turn the biomass can be used to produce food, feed, fertilizer and biofuels. However, along with CO2, coal-based flue gas will inevitably introduce heavy metals, which have a high affinity to bind algal cells, could be toxic to the organisms and if transferred to the products could limit their uses. This study seeks to address the distribution and impact of heavy metals present in flue gas on microalgae production systems. To comprehend its effects, algae Scenedesmus obliquus was grown in batch reactors in a multimetal system. Ten heavy metals (Cu, Co, Zn, Pb, As, Se, Cr, Hg, Ni and Cd) were selected and were evaluated at four concentrations (1X, 2X, 5X and 10X). Results show that most heavy metals accumulated mainly in biomass and were found in very low concentrations in media. Hg was shown to be lost from the culture, with low amounts present in the biomass. An upper limit for As uptake was observed, suggesting its likelihood to build-up in the system during medium recycle. The As limited bioaccumulation was overcome by addition of sulfur to the algal medium. Heavy metal at 2X, 5X and 10X inhibited both growth and lipid production, while at the reference concentration both biomass and lipids yields were increased. Heavy metal concentrations in the medium and biomass were time dependent, and at the end of the cultivation most heavy metals in the supernatant solution complied with the recommendations for irrigation water, while biomass was below limits for cattle and poultry feed, fertilizer, plastic and paper. This research shows that bioremediation of CO2 and heavy metals in combination with energy production can be integrated, which is an environmentally friendly form of biotechnology.

  8. VESTA - gas distribution system for tomorrow and today

    SciTech Connect

    Huebler, J.; Rush, B.

    1983-01-01

    By combining hardware that has been developed for electronic games and home computers with straightforward modifications to currently used gas distribution equipment, it is possible to design a practical, cost-effective ''gas industry dream system'' with capabilities that include automatic meter reading and shut-off, simple buried pipe location, automatic leak location and repair without excavation, and remote pressure monitoring. The Institute of Gas Technology calls the System ''VESTA'', an acronym for Versatile Energy System Total Approach, whose two essential features are the total approach to problem solving and its distributed intelligence electronics. The authors describe current designs and costs of the VESTA system. 2 figures.

  9. Fugitive methane emissions from leak-prone natural gas distribution infrastructure in urban environments.

    PubMed

    Hendrick, Margaret F; Ackley, Robert; Sanaie-Movahed, Bahare; Tang, Xiaojing; Phillips, Nathan G

    2016-06-01

    Fugitive emissions from natural gas systems are the largest anthropogenic source of the greenhouse gas methane (CH4) in the U.S. and contribute to the risk of explosions in urban environments. Here, we report on a survey of CH4 emissions from 100 natural gas leaks in cast iron distribution mains in Metro Boston, MA. Direct measures of CH4 flux from individual leaks ranged from 4.0 - 2.3 × 10(4) g CH4•day(-1). The distribution of leak size is positively skewed, with 7% of leaks contributing 50% of total CH4 emissions measured. We identify parallels in the skewed distribution of leak size found in downstream systems with midstream and upstream stages of the gas process chain. Fixing 'superemitter' leaks will disproportionately stem greenhouse gas emissions. Fifteen percent of leaks surveyed qualified as potentially explosive (Grade 1), and we found no difference in CH4 flux between Grade 1 leaks and all remaining leaks surveyed (p = 0.24). All leaks must be addressed, as even small leaks cannot be disregarded as 'safely leaking.' Key methodological impediments to quantifying and addressing the impacts of leaking natural gas distribution infrastructure involve inconsistencies in the manner in which gas leaks are defined, detected, and classified. To address this need, we propose a two-part leak classification system that reflects both the safety and climatic impacts of natural gas leaks.

  10. Gas Content and Star Formation Efficiency of Massive Main Sequence Galaxies at z~3-4

    NASA Astrophysics Data System (ADS)

    Schinnerer, Eva; Groves, Brent; Karim, Alexander; Sargent, Mark T.; Oesch, Pascal; Le Fevre, Olivier; Tasca, Lidia; Magnelli, Benjamin; Cassata, Paolo; Smolcic, Vernesa

    2016-01-01

    Recent observations have shown that the neutral gas content and star formation efficiency of massive (with log(stellar masses) > 10), normal star forming galaxies, i.e. they reside on the main sequence of star forming galaxies, are steadily decreasing from the peak of star formation activity (at redshifts of z~2) till today. This decrease is coincident with the observed decline in the cosmic star formation rate density over this time range. However, only few observations have probed the evolution of the gas content and star formation efficiency beyond this peak epoch when the cosmic star formation rate density has been increasing, i.e. at redshifts of z~3-4.We will present new ALMA rest-frame 250um continuum detections of 45 massive, normal star forming galaxies in this critical redshift interval selected in the COSMOS deep field. Using the sub-mm continnum as proxy for the cold neutral gas content, we find gas mass fractions and depletions similar to those reported during the peak epoch of star formation. We will discuss our findings in the context of results from lower redshift observations and model expectations.

  11. Using hydrologic measurements to investigate free-phase gas ebullition in a Maine peatland, USA

    NASA Astrophysics Data System (ADS)

    Bon, C. E.; Reeve, A. S.; Slater, L.; Comas, X.

    2014-03-01

    Northern peatlands cover more than 350 million ha and are an important source of methane (CH4) and other biogenic gases contributing to climate change. Free-phase gas (FPG) accumulation and episodic release has recently been recognized as an important mechanism for biogenic gas flux from peatlands. It is likely that gas production and groundwater flow are interconnected in peatlands: groundwater flow influences gas production by regulating geochemical conditions and nutrient supply available for methanogenesis, while FPG influences groundwater flow through a reduction in peat permeability and by creating excess pore water pressures. Water samples collected from three well sites at Caribou Bog, Maine, show substantial dissolved CH4 (5-16 mg L-1) in peat waters below 2 m depth and an increase in concentrations with depth. This suggests production and storage of CH4 in deep peat that may be episodically released as FPG. Two min increment pressure transducer data reveal approximately 5 cm fluctuations in hydraulic head from both deep and shallow peat that are believed to be indicative of FPG release. FPG release persists up to 24 h during decreasing atmospheric pressure and a rising water table. Preferential flow is seen towards an area of relatively lower hydraulic head associated with the esker and pool system. Increased CH4 concentrations are also found at the depth of the esker crest, suggesting that the high permeability esker is acting as a conduit for groundwater flow, driving a downward transport of labile carbon, resulting in higher rates of CH4 production.

  12. Using hydrologic measurements to investigate free phase gas ebullition in a Maine Peatland, USA

    NASA Astrophysics Data System (ADS)

    Bon, C. E.; Reeve, A. S.; Slater, L.; Comas, X.

    2013-07-01

    Northern Peatlands cover more than 350 million ha and are an important source of methane (CH4) and other biogenic gases contributing to climate change. Free phase gas (FPG) accumulation and episodic release has recently been recognized as an important mechanism for biogenic gas flux from peatlands. It is likely that gas production and groundwater flow are interconnected in peatlands: groundwater flow influences gas production by regulating geochemical conditions and nutrient supply available for methanogenesis while FPG influences groundwater flow through a reduction in peat permeability and by creating excess pore water pressures. Water samples collected from three well sites at Caribou Bog, Maine, show substantial dissolved CH4 (5-16 mg L-1) in peat waters below 2 m depth and an increase in concentrations with depth. This suggests substantial production and storage of CH4 in deep peat that may be episodically released as FPG. Two minute increment pressure transducer data reveal approximately 5 cm fluctuations in hydraulic head from both deep and shallow peat that are believed to be indicative of FPG release. FPG release persists up to 24 h during decreasing atmospheric pressure and a rising water table. Preferential flow is seen towards an area of relatively lower hydraulic head associated with the esker and pool system. Increased CH4 concentrations are also found at the depth of the esker crest suggesting that the high permeability esker is acting as a conduit for groundwater flow, driving a downward transport of labile carbon, resulting in higher rates of CH4 production.

  13. Model documentation: Natural gas transmission and distribution model of the National Energy Modeling System. Volume 1

    SciTech Connect

    1995-02-17

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of integrated Analysis and Forecasting of the Energy information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The methodology employed allows the analysis of impacts of regional capacity constraints in the interstate natural gas pipeline network and the identification of pipeline capacity expansion requirements. There is an explicit representation of core and noncore markets for natural gas transmission and distribution services, and the key components of pipeline tariffs are represented in a pricing algorithm. Natural gas pricing and flow patterns are derived by obtaining a market equilibrium across the three main elements of the natural gas market: the supply element, the demand element, and the transmission and distribution network that links them. The NGTDM consists of four modules: the Annual Flow Module, the Capacity F-expansion Module, the Pipeline Tariff Module, and the Distributor Tariff Module. A model abstract is provided in Appendix A.

  14. Modeling Gas Distribution in Protoplanetary Accretion Disks

    NASA Astrophysics Data System (ADS)

    Kronberg, Martin; Lewis, Josiah; Brittain, Sean

    2010-07-01

    Protoplanetary accretion disks are disks of dust and gas which surround and feed material onto a forming star in the earliest stages of its evolution. One of the most useful methods for studying these disks is near infrared spectroscopy of rovibrational CO emission. This paper presents the methods in which synthetically generated spectra are modeled and fit to spectral data gathered from protoplanetary disks. This paper also discussed the methods in which this code can be improved by modifying the code to run a Monte Carlo analysis of best fit across the CONDOR cluster at Clemson University, thereby allowing for the creation of a catalog of protoplanetary disks with detailed information about them as gathered from the model.

  15. Distribution of the background gas in the MITICA accelerator

    NASA Astrophysics Data System (ADS)

    Sartori, E.; Dal Bello, S.; Serianni, G.; Sonato, P.

    2013-02-01

    MITICA is the ITER neutral beam test facility to be built in Padova for the generation of a 40A D- ion beam with a 16×5×16 array of 1280 beamlets accelerated to 1MV. The background gas pressure distribution and the particle flows inside MITICA accelerator are critical aspects for stripping losses, generation of secondary particles and beam non-uniformities. To keep the stripping losses in the extraction and acceleration stages reasonably low, the source pressure should be 0.3 Pa or less. The gas flow in MITICA accelerator is being studied using a 3D Finite Element code, named Avocado. The gas-wall interaction model is based on the cosine law, and the whole vacuum system geometry is represented by a view factor matrix based on surface discretization and gas property definitions. Pressure distribution and mutual fluxes are then solved linearly. In this paper the result of a numerical simulation is presented, showing the steady-state pressure distribution inside the accelerator when gas enters the system at room temperature. The accelerator model is limited to a horizontal slice 400 mm high (1/4 of the accelerator height). The pressure profile at solid walls and through the beamlet axis is obtained, allowing the evaluation and the discussion of the background gas distribution and nonuniformity. The particle flux at the inlet and outlet boundaries (namely the grounded grid apertures and the lateral conductances respectively) will be discussed.

  16. The gas distribution in the high-redshift cluster MS 1054-0321

    NASA Astrophysics Data System (ADS)

    Mirakhor, M. S.; Birkinshaw, M.

    2016-04-01

    We investigate the gas mass distribution in the high-redshift cluster MS 1054-0321 using Chandra X-ray and One Centimetre Receiver array Sunyaev-Zel'dovich (SZ) effect data. We use a superposition of offset β-type models to describe the composite structure of MS 1054-0321. We find gas mass fractions f_{gas}^{X {-}ray} = 0.087_{-0.001}^{+0.005} and f_{gas}^SZ=0.094_{-0.001}^{+0.003} for the (main) eastern component of MS 1054-0321 using X-ray or SZ data, but f_{gas}^{X {-}ray}=0.030_{-0.014}^{+0.010} for the western component. The gas mass fraction for the eastern component is in agreement with some results reported in the literature, but inconsistent with the cosmic baryon fraction. The low-gas mass fraction for the western component is likely to be a consequence of gas stripping during the ongoing merger. The gas mass fraction of the integrated system is 0.060_{-0.009}^{+0.004}: we suggest that the missing baryons from the western component are present as hot diffuse gas which is poorly represented in existing X-ray images. The missing gas could appear in sensitive SZ maps.

  17. Long-Range Untethered Real-Time Live Gas Main Robotic Inspection System

    SciTech Connect

    Hagen Schempf; Daphne D'Zurko

    2004-10-31

    Under funding from the Department of Energy (DOE) and the Northeast Gas Association (NGA), Carnegie Mellon University (CMU) developed an untethered, wireless remote controlled inspection robot dubbed Explorer. The project entailed the design and prototyping of a wireless self-powered video-inspection robot capable of accessing live 6- and 8-inch diameter cast-iron and steel mains, while traversing turns and Ts and elbows under real-time control with live video feedback to an operator. The design is that of a segmented actively articulated and wheel-leg powered robot design, with fisheye imaging capability and self-powered battery storage and wireless real-time communication link. The prototype was functionally tested in an above ground pipe-network, in order to debug all mechanical, electrical and software subsystems, and develop the necessary deployment and retrieval, as well as obstacle-handling scripts. A pressurized natural gas test-section was used to certify it for operation in natural gas at up to 60 psig. Two subsequent live-main field-trials in both cast-iron and steel pipe, demonstrated its ability to be safely launched, operated and retrieved under real-world conditions. The system's ability to safely and repeatably exidrecover from angled and vertical launchers, traverse multi-thousand foot long pipe-sections, make T and varied-angle elbow-turns while wirelessly sending live video and handling command and control messages, was clearly demonstrated. Video-inspection was clearly shown to be a viable tool to understand the state of this critical buried infrastructure, irrespective of low- (cast-iron) or high-pressure (steel) conditions. This report covers the different aspects of specifications, requirements, design, prototyping, integration and testing and field-trialing of the Explorer platform.

  18. CARMA LARGE AREA STAR FORMATION SURVEY: STRUCTURE AND KINEMATICS OF DENSE GAS IN SERPENS MAIN

    SciTech Connect

    Lee, Katherine I.; Storm, Shaye; Mundy, Lee G.; Teuben, Peter; Pound, Marc W.; Salter, Demerese M.; Chen, Che-Yu; Fernández-López, Manuel; Looney, Leslie W.; Segura-Cox, Dominique; Rosolowsky, Erik; Arce, Héctor G.; Plunkett, Adele L.; Ostriker, Eve C.; Shirley, Yancy L.; Kwon, Woojin; Kauffmann, Jens; Tobin, John J.; Volgenau, N. H.; Tassis, Konstantinos; and others

    2014-12-20

    We present observations of N{sub 2}H{sup +} (J = 1 → 0), HCO{sup +} (J = 1 → 0), and HCN (J = 1 → 0) toward the Serpens Main molecular cloud from the CARMA Large Area Star Formation Survey (CLASSy). We mapped 150 arcmin{sup 2} of Serpens Main with an angular resolution of ∼7''. The gas emission is concentrated in two subclusters (the NW and SE subclusters). The SE subcluster has more prominent filamentary structures and more complicated kinematics compared to the NW subcluster. The majority of gas in the two subclusters has subsonic to sonic velocity dispersions. We applied a dendrogram technique with N{sub 2}H{sup +}(1-0) to study the gas structures; the SE subcluster has a higher degree of hierarchy than the NW subcluster. Combining the dendrogram and line fitting analyses reveals two distinct relations: a flat relation between nonthermal velocity dispersion and size, and a positive correlation between variation in velocity centroids and size. The two relations imply a characteristic depth of 0.15 pc for the cloud. Furthermore, we have identified six filaments in the SE subcluster. These filaments have lengths of ∼0.2 pc and widths of ∼0.03 pc, which is smaller than a characteristic width of 0.1 pc suggested by Herschel observations. The filaments can be classified into two types based on their properties. The first type, located in the northeast of the SE subcluster, has larger velocity gradients, smaller masses, and nearly critical mass-per-unit-length ratios. The other type, located in the southwest of the SE subcluster, has the opposite properties. Several YSOs are formed along two filaments which have supercritical mass per unit length ratios, while filaments with nearly critical mass-per-unit-length ratios are not associated with YSOs, suggesting that stars are formed on gravitationally unstable filaments.

  19. 40 CFR Table W - 7 of Subpart W-Default Methane Emission Factors for Natural Gas Distribution

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Emission Factors for Natural Gas Distribution W Table W Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petroleum and Natural Gas... for Natural Gas Distribution Natural gas distribution Emission factor (scf/hour/component)...

  20. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    SciTech Connect

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  1. Methane Leaks from Natural Gas Systems Follow Extreme Distributions

    DOE PAGES

    Brandt, Adam R.; Heath, Garvin A.; Cooley, Daniel

    2016-10-14

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ~15,000 measurements from 18 prior studies, we show that all available natural gas leakage datasets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the totalmore » leakage volume. While prior studies used lognormal model distributions, we show that lognormal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of datasets to increase sample size is not recommended due to apparent deviation between sampled populations. Finally, understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.« less

  2. Methane Leaks from Natural Gas Systems Follow Extreme Distributions.

    PubMed

    Brandt, Adam R; Heath, Garvin A; Cooley, Daniel

    2016-11-15

    Future energy systems may rely on natural gas as a low-cost fuel to support variable renewable power. However, leaking natural gas causes climate damage because methane (CH4) has a high global warming potential. In this study, we use extreme-value theory to explore the distribution of natural gas leak sizes. By analyzing ∼15 000 measurements from 18 prior studies, we show that all available natural gas leakage data sets are statistically heavy-tailed, and that gas leaks are more extremely distributed than other natural and social phenomena. A unifying result is that the largest 5% of leaks typically contribute over 50% of the total leakage volume. While prior studies used log-normal model distributions, we show that log-normal functions poorly represent tail behavior. Our results suggest that published uncertainty ranges of CH4 emissions are too narrow, and that larger sample sizes are required in future studies to achieve targeted confidence intervals. Additionally, we find that cross-study aggregation of data sets to increase sample size is not recommended due to apparent deviation between sampled populations. Understanding the nature of leak distributions can improve emission estimates, better illustrate their uncertainty, allow prioritization of source categories, and improve sampling design. Also, these data can be used for more effective design of leak detection technologies.

  3. Numerical simulation of landfill gas pressure distribution in landfills.

    PubMed

    Xi, Yonghui; Xiong, Hao

    2013-11-01

    Landfill gas emissions are recognized as one of the three major concerns in municipal solid waste landfills. There are many factors that affect the generation of landfill gas when the landfill is capped. In this article, a model has been developed based on the theory of porous media flow. The model could predict the pressure distribution of landfill gas in landfill, coupling the effect of landfill settlement. According to the simulation analysis of landfill, it was found that: (a) the landfill gas pressure would reach a peak after 1.5 years, then begin to decline, and the rate of decay would slow down after 10 years; (b) the influence radius of the gas wells is limited; (c) the peak value of landfill gas pressure is larger, it appears later and the rate of decay is slower when the landfill settlement is considered in the model; (d) the calculation of excess gas pressure in landfill under different negative pressures of the extraction well is compared between this model and another model, and the results show that the relative pressure distribution form and range are almost the same.

  4. Is the Grand Tack model compatible with the orbital distribution of main belt asteroids?

    NASA Astrophysics Data System (ADS)

    Deienno, Rogerio; Gomes, Rodney S.; Walsh, Kevin J.; Morbidelli, Alessandro; Nesvorný, David

    2016-07-01

    The Asteroid Belt is characterized by the radial mixing of bodies with different physical properties, a very low mass compared to Minimum Mass Solar Nebula expectations and has an excited orbital distribution, with eccentricities and inclinations covering the entire range of values allowed by the constraints of dynamical stability. Models of the evolution of the Asteroid Belt show that the origin of its structure is strongly linked to the process of terrestrial planet formation. The Grand Tack model presents a possible solution to the conundrum of reconciling the small mass of Mars with the properties of the Asteroid Belt, including the mass depletion, radial mixing and orbital excitation. However, while the inclination distribution produced in the Grand Tack model is in good agreement with the one observed, the eccentricity distribution is skewed towards values larger than those found today. Here, we evaluate the evolution of the orbital properties of the Asteroid Belt from the end of the Grand Tack model (at the end of the gas nebula phase when planets emerge from the dispersing gas disk), throughout the subsequent evolution of the Solar System including an instability of the Giant Planets approximately 400 Myr later. Before the instability, the terrestrial planets were modeled on dynamically cold orbits with Jupiter and Saturn locked in a 3:2 mean motion resonance. The model continues for an additional 4.1 Gyr after the giant planet instability. Our results show that the eccentricity distribution obtained in the Grand Tack model evolves towards one very similar to that currently observed, and the semimajor axis distribution does the same. The inclination distribution remains nearly unchanged with a slight preference for depletion at low inclination; this leads to the conclusion that the inclination distribution at the end of the Grand Tack is a bit over-excited. Also, we constrain the primordial eccentricities of Jupiter and Saturn, which have a major influence

  5. 75 FR 59705 - SourceGas Distribution LLC; Bay Gas Storage, LLC; Enterprise Texas Pipeline LLC; Dow Intrastate...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-28

    ... Distribution LLC; Bay Gas Storage, LLC; Enterprise Texas Pipeline LLC; Dow Intrastate Gas Company; ONEOK Field Services Company, L.L.C.; Corning Natural Gas Corporation; Notice of Baseline Filings September 21,...

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

    SciTech Connect

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

    2009-09-01

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

  7. 78 FR 56685 - SourceGas Distribution LLC; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-13

    ... Energy Regulatory Commission SourceGas Distribution LLC; Notice of Application Take notice that on August 27, 2013, SourceGas Distribution LLC (SourceGas), 600 12th Street, Suite 300, Golden, Colorado 80401..., without further commission authorization, provide natural gas distribution service. SourceGas...

  8. Energy direct inputs and greenhouse gas emissions of the main industrial trawl fishery of Brazil.

    PubMed

    Port, Dagoberto; Perez, Jose Angel Alvarez; de Menezes, João Thadeu

    2014-11-15

    This study provides first-time estimates of direct fuel inputs and greenhouse gas emissions produced by the trawl fishing fleet operating off southeastern and southern Brazil. Analyzed data comprised vessel characteristics, landings, fishing areas and trawling duration of 10,144 fishing operations monitored in Santa Catarina State from 2003 to 2011. Three main fishing strategies were differentiated: 'shrimp trawling', 'slope trawling' and 'pair trawling'. Jointly these operations burned over 9.1 million liters of diesel to land 342.3 million kilograms of fish and shellfish. Annually, 0.023-0.031 l were consumed for every kg of catch landed. Because all fishing strategies relied on multispecific catches to raise total incomes, estimates of fuel use intensity were generally low but increased 200-900% if only nominal targets were considered. In nine years, trawling operations emitted 6.69 GgC to the atmosphere, between 2300 and 3300 tons CO2 per year.

  9. Energy direct inputs and greenhouse gas emissions of the main industrial trawl fishery of Brazil.

    PubMed

    Port, Dagoberto; Perez, Jose Angel Alvarez; de Menezes, João Thadeu

    2016-06-15

    This study provides first-time estimates of direct fuel inputs and greenhouse gas emissions produced by the trawl fishing fleet operating off southeastern and southern Brazil. Analyzed data comprised vessel characteristics, landings, fishing areas and trawling duration of 10,144 fishing operations monitored in Santa Catarina State from 2003 to 2011. Three main fishing strategies were differentiated: 'shrimp trawling', 'slope trawling' and 'pair trawling'. Jointly these operations burned over 141.5millionl of diesel to land 342.3millionkg of fish and shellfish. Annually, 0.36-0.48l were consumed for every kg of catch landed. Because all fishing strategies relied on multispecific catches to raise total incomes, estimates of fuel use intensity were generally low but increased 316-1025% if only nominal targets were considered. In nine years, trawling operations emitted 104.07GgC to the atmosphere, between 36,800-49,500tons CO2 per year.

  10. The Gas Distribution in the Outer Regions of Galaxy Clusters

    NASA Technical Reports Server (NTRS)

    Eckert, D.; Vazza, F.; Ettori, S.; Molendi, S.; Nagai, D.; Lau, E. T.; Roncarelli, M.; Rossetti, M.; Snowden, L.; Gastaldello, F.

    2012-01-01

    Aims. We present our analysis of a local (z = 0.04 - 0.2) sample of 31 galaxy clusters with the aim of measuring the density of the X-ray emitting gas in cluster outskirts. We compare our results with numerical simulations to set constraints on the azimuthal symmetry and gas clumping in the outer regions of galaxy clusters. Methods. We have exploited the large field-of-view and low instrumental background of ROSAT/PSPC to trace the density of the intracluster gas out to the virial radius, We stacked the density profiles to detect a signal beyond T200 and measured the typical density and scatter in cluster outskirts. We also computed the azimuthal scatter of the profiles with respect to the mean value to look for deviations from spherical symmetry. Finally, we compared our average density and scatter profiles with the results of numerical simulations. Results. As opposed to some recent Suzaku results, and confirming previous evidence from ROSAT and Chandra, we observe a steepening of the density profiles beyond approximately r(sub 500). Comparing our density profiles with simulations, we find that non-radiative runs predict density profiles that are too steep, whereas runs including additional physics and/ or treating gas clumping agree better with the observed gas distribution. We report high-confidence detection of a systematic difference between cool-core and non cool-core clusters beyond approximately 0.3r(sub 200), which we explain by a different distribution of the gas in the two classes. Beyond approximately r(sub 500), galaxy clusters deviate significantly from spherical symmetry, with only small differences between relaxed and disturbed systems. We find good agreement between the observed and predicted scatter profiles, but only when the 1% densest clumps are filtered out in the ENZO simulations. Conclusions. Comparing our results with numerical simulations, we find that non-radiative simulations fail to reproduce the gas distribution, even well outside

  11. The Gas Distribution in Galaxy Cluster Outer Regions

    NASA Technical Reports Server (NTRS)

    Eckert, D.; Vazza, F.; Ettori, S.; Molendi, S.; Nagai, D.; Laue, E. T.; Roncarelli, M.; Rossetti, M.; Snowden, S. L.; Gastaldello, F.

    2012-01-01

    Aims. We present the analysis of a local (z = 0.04 - 0.2) sample of 31 galaxy clusters with the aim of measuring the density of the X-ray emitting gas in cluster outskirts. We compare our results with numerical simulations to set constraints on the azimuthal symmetry and gas clumping in the outer regions of galaxy clusters. Methods. We exploit the large field-of-view and low instrumental background of ROSAT/PSPC to trace the density of the intracluster gas out to the virial radius. We perform a stacking of the density profiles to detect a signal beyond r200 and measure the typical density and scatter in cluster outskirts. We also compute the azimuthal scatter of the profiles with respect to the mean value to look for deviations from spherical symmetry. Finally, we compare our average density and scatter profiles with the results of numerical simulations. Results. As opposed to some recent Suzaku results, and confirming previous evidence from ROSAT and Chandra, we observe a steepening of the density profiles beyond approximately r(sub 500). Comparing our density profiles with simulations, we find that non-radiative runs predict too steep density profiles, whereas runs including additional physics and/or treating gas clumping are in better agreement with the observed gas distribution. We report for the first time the high-confidence detection of a systematic difference between cool-core and non-cool core clusters beyond 0.3r(sub 200), which we explain by a different distribution of the gas in the two classes. Beyond r(sub 500), galaxy clusters deviate significantly from spherical symmetry, with only little differences between relaxed and disturbed systems. We find good agreement between the observed and predicted scatter profiles, but only when the 1% densest clumps are filtered out in the simulations. Conclusions. Comparing our results with numerical simulations, we find that non-radiative simulations fail to reproduce the gas distribution, even well outside cluster

  12. Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA

    USGS Publications Warehouse

    Remo, Jonathan; Heine, Ruben A.; Ickes, Brian

    2016-01-01

    In this study, we compared pre-lock-and-dam (ca. 1925) with a modern longitudinal survey of main-channel-bed sediments along a 740-km segment of the upper Mississippi River (UMR) between Davenport, IA, and Cairo, IL. This comparison was undertaken to gain a better understanding of how bed sediments are distributed longitudinally and to assess change since the completion of the UMR lock and dam navigation system and Missouri River dams (i.e., mid-twentieth century). The comparison of the historic and modern longitudinal bed sediment surveys showed similar bed sediment sizes and distributions along the study segment with the majority (> 90%) of bed sediment samples having a median diameter (D50) of fine to coarse sand. The fine tail (≤ D10) of the sediment size distributions was very fine to medium sand, and the coarse tail (≥ D90) of sediment-size distribution was coarse sand to gravel. Coarsest sediments in both surveys were found within or immediately downstream of bedrock-floored reaches. Statistical analysis revealed that the particle-size distributions between the survey samples were statistically identical, suggesting no overall difference in main-channel-bed sediment-size distribution between 1925 and present. This was a surprising result given the magnitude of river engineering undertaken along the study segment over the past ~ 90 years. The absence of substantial differences in main-channel-bed-sediment size suggests that flow competencies within the highly engineered navigation channel today are similar to conditions within the less-engineered historic channel.

  13. Particle size distribution of main-channel-bed sediments along the upper Mississippi River, USA

    NASA Astrophysics Data System (ADS)

    Remo, Jonathan W. F.; Heine, Reuben A.; Ickes, Brian S.

    2016-07-01

    In this study, we compared pre-lock-and-dam (ca. 1925) with a modern longitudinal survey of main-channel-bed sediments along a 740-km segment of the upper Mississippi River (UMR) between Davenport, IA, and Cairo, IL. This comparison was undertaken to gain a better understanding of how bed sediments are distributed longitudinally and to assess change since the completion of the UMR lock and dam navigation system and Missouri River dams (i.e., mid-twentieth century). The comparison of the historic and modern longitudinal bed sediment surveys showed similar bed sediment sizes and distributions along the study segment with the majority (> 90%) of bed sediment samples having a median diameter (D50) of fine to coarse sand. The fine tail (≤ D10) of the sediment size distributions was very fine to medium sand, and the coarse tail (≥ D90) of sediment-size distribution was coarse sand to gravel. Coarsest sediments in both surveys were found within or immediately downstream of bedrock-floored reaches. Statistical analysis revealed that the particle-size distributions between the survey samples were statistically identical, suggesting no overall difference in main-channel-bed sediment-size distribution between 1925 and present. This was a surprising result given the magnitude of river engineering undertaken along the study segment over the past 90 years. The absence of substantial differences in main-channel-bed-sediment size suggests that flow competencies within the highly engineered navigation channel today are similar to conditions within the less-engineered historic channel.

  14. Characterization of real gas properties for space shuttle main engine fuel turbine and performance calculations

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.

    1986-01-01

    Real thermodynamic and transport properties of hydrogen, steam, the SSME mixture, and air are developed. The SSME mixture properties are needed for the analysis of the space shuttle main engine fuel turbine. The mixture conditions for the gases, except air, are presented graphically over a temperature range from 800 to 1200 K, and a pressure range from 1 to 500 atm. Air properties are given over a temperature range of 320 to 500 K, which are within the bounds of the thermodynamics programs used, in order to provide mixture data which is more easily checked (than H2/H2O). The real gas property variation of the SSME mixture is quantified. Polynomial expressions, needed for future computer analysis, for viscosity, Prandtl number, and thermal conductivity are given for the H2/H2O SSME fuel turbine mixture at a pressure of 305 atm over a range of temperatures from 950 to 1140 K. These conditions are representative of the SSME turbine operation. Performance calculations are presented for the space shuttle main engine (SSME) fuel turbine. The calculations use the air equivalent concept. Progress towards obtaining the capability to evaluate the performance of the SSME fuel turbine, with the H2/H2O mixture, is described.

  15. Relationships between sinkholes areal distribution and main tectonic alignments in Abruzzo (Central Italy)

    NASA Astrophysics Data System (ADS)

    Ferrini, G.; Moretti, A.; De Rose, C.; Stagnini, E.,; Serafini, M.

    2012-04-01

    present there is no evidence of hydrothermal activity or gas diffusion, morphological and geostructural analogy with the hydrothermal field of San Vittorino (Rieti) suggest dissolution processes related to the rising of underground mineralized fluids (piping) and a subsequent collapse phase, in a classic sink-hole evolutionary model. To note the areal distribution of these elements developed in a narrow band , WNW-ESE oriented, running for about 40 km parallel back to the tectonic front of the Gran Sasso and coinciding, with good approximation, to the seismogenic source of the earthquake of April 6th 2009 and of the major historical earthquakes which hit the region. Geophysical survey carried out after the last strong seismic event pointed out the presence of large hidden cavities developed in the Neogene sedimentary filling of the L'Aquila basin confirming that the phenomenon cannot be considered exhausted; then a geochemical mapping of the all area is started to identify suitable sites for monitoring fluid in relation to seismic activity and to evaluate the risk of potential, sudden phenomena of gravitational collapse.

  16. Decompression vs. Decomposition: Distribution, Amount, and Gas Composition of Bubbles in Stranded Marine Mammals

    PubMed Central

    de Quirós, Yara Bernaldo; González-Diaz, Oscar; Arbelo, Manuel; Sierra, Eva; Sacchini, Simona; Fernández, Antonio

    2012-01-01

    Gas embolic lesions linked to military sonar have been described in stranded cetaceans including beaked whales. These descriptions suggest that gas bubbles in marine mammal tissues may be more common than previously thought. In this study we have analyzed gas amount (by gas score) and gas composition within different decomposition codes using a standardized methodology. This broad study has allowed us to explore species-specific variability in bubble prevalence, amount, distribution, and composition, as well as masking of bubble content by putrefaction gases. Bubbles detected within the cardiovascular system and other tissues related to both pre- and port-mortem processes are a common finding on necropsy of stranded cetaceans. To minimize masking by putrefaction gases, necropsy, and gas sampling must be performed as soon as possible. Before 24 h post mortem is recommended but preferably within 12 h post mortem. At necropsy, amount of bubbles (gas score) in decomposition code 2 in stranded cetaceans was found to be more important than merely presence vs. absence of bubbles from a pathological point of view. Deep divers presented higher abundance of gas bubbles, mainly composed of 70% nitrogen and 30% CO2, suggesting a higher predisposition of these species to suffer from decompression-related gas embolism. PMID:22675306

  17. Applying Systems Engineering to Improve the Main Gas Turbine Exhaust System Maintenance Strategy for the CG-47 Ticonderoga Class Cruiser

    DTIC Science & Technology

    2015-09-01

    IMPROVE THE MAIN GAS TURBINE EXHAUST SYSTEM MAINTENANCE STRATEGY FOR THE CG-47 TICONDEROGA CLASS CRUISER by Robert D. Sparks September 2015 Thesis...TURBINE EXHAUST SYSTEM MAINTENANCE STRATEGY FOR THE CG-47 TICONDEROGA CLASS CRUISER 5. FUNDING NUMBERS 6. AUTHOR(S) Sparks, Robert D. 7. PERFORMING...recommendations for improvement of the main gas turbine exhaust system maintenance strategy are the focus of this thesis. The analysis recommends a

  18. A scaling law of radial gas distribution in disk galaxies

    NASA Technical Reports Server (NTRS)

    Wang, Zhong

    1990-01-01

    Based on the idea that local conditions within a galactic disk largely determine the region's evolution time scale, researchers built a theoretical model to take into account molecular cloud and star formations in the disk evolution process. Despite some variations that may be caused by spiral arms and central bulge masses, they found that many late-type galaxies show consistency with the model in their radial atomic and molecular gas profiles. In particular, researchers propose that a scaling law be used to generalize the gas distribution characteristics. This scaling law may be useful in helping to understand the observed gas contents in many galaxies. Their model assumes an exponential mass distribution with disk radius. Most of the mass are in atomic gas state at the beginning of the evolution. Molecular clouds form through a modified Schmidt Law which takes into account gravitational instabilities in a possible three-phase structure of diffuse interstellar medium (McKee and Ostriker, 1977; Balbus and Cowie, 1985); whereas star formation proceeds presumably unaffected by the environmental conditions outside of molecular clouds (Young, 1987). In such a model both atomic and molecular gas profiles in a typical galactic disk (as a result of the evolution) can be fitted simultaneously by adjusting the efficiency constants. Galaxies of different sizes and masses, on the other hand, can be compared with the model by simply scaling their characteristic length scales and shifting their radial ranges to match the assumed disk total mass profile sigma tot(r).

  19. Garrotxa simulations: Hot gas distribution around Milky Way size galaxies at z=0

    NASA Astrophysics Data System (ADS)

    Roca-Fàbrega, S.; Colin, P.,; Valenzuela, O.; Figueras, F.; Krongol, Y.

    2017-03-01

    We present a new set of cosmological Milky Way size galaxy simulations using ART. In our simulations the main system has been evolved inside a 28 Mpc cosmological box with a spatial resolution of 109 pc. At z=0 our systems have an M_{vir}=6-8 × 10^{11} M_⊙. In several of our models we have observed how a well defined disk is formed inside the dark matter halo and the overall amount of gas and stars is comparable with MW observations. Several non-axisymmetric structures arise out of the disk: spirals, bars and also a warp. We have also observed that a huge reservoir of hot gas is present at large distances from the disk, embedded in the dark matter halo region, accounting for only a fraction of the ”missing baryons”. Gas column density, emission (EM) and dispersion (DM) measure have been computed from inside the simulated disk at a position of 8 kpc from the center and in several directions. Our preliminary results reveal that the distribution of hot gas is non- isotropic according with observations. Also its metallic content presents a clear bimodality what is a consequence of a recent accretion of a satellite galaxy among others. After a careful analysis we confirm that due to the anisotropy in the gas distribution a new observational parameter needs to be defined to recover the real distribution of hot gas in the galactic halo.

  20. Spatial and temporal distributions of lung cancer histopathology in the state of Maine.

    PubMed

    Hosgood, H Dean; Farah, Christopher; Black, Candice C; Schwenn, Molly; Hock, Janet M

    2013-10-01

    Maine has among the highest rates of lung cancer in the United States (US). Maine serves as a geographical representation of US rural communities, and their associated health disparities. As the key risks of tobacco use decrease and radon abatement increases, previously obscured environmental exposures may measurably contribute to the attributable risk fraction of lung cancer. To generate hypotheses of novel environmental exposures associated with lung cancer, we investigated if there was non-random spatial distribution of lung cancer in Maine. Case data (n = 14,038) between 1995 and 2006 were obtained from the Maine Cancer Registry. Population data were obtained from the 2000 US Census. We assessed the spatial distribution of lung cancers among white cases by histopathology subtype [non-small cell lung carcinoma (NSCLC): adenocarcinoma (n = 3680), squamous cell (n = 2801) and large cell (n = 1195); and small cell lung carcinoma (SCLC) (n = 1994)], using spatial scan statistic, assuming a discrete Poisson distribution adjusted for age and population density. Because of time-dependent trends in lung cancer differential diagnostic criteria, we repeated our analyses, limiting it to 2002-2006. While SCLC rates were equivalent across the state, we identified discrete regions with elevated rates of adenocarcinoma among females and squamous cell carcinoma among males. Independent of gender, the most striking geospatial observation was elevated large cell lung cancer specifically in one of the poorest counties in the US. A selective spatial distribution of large cell lung cancer has not been previously reported. More research is needed to identify factors inducing large cell carcinoma pathology, and to determine if in rural communities health disparities are associated with increased risk for this diagnosis.

  1. Effect of rotational disruption on the size-frequency distribution of the Main Belt asteroid population

    NASA Astrophysics Data System (ADS)

    Jacobson, Seth A.; Marzari, Francesco; Rossi, Alessandro; Scheeres, Daniel J.; Davis, Donald R.

    2014-03-01

    The size distribution of small asteroids in the Main Belt is assumed to be determined by an equilibrium between the creation of new bodies out of the impact debris of larger asteroids and the destruction of small asteroids by collisions with smaller projectiles. However, for a diameter less than 6 km, we find that YORP-induced rotational disruption significantly contributes to the erosion even exceeding the effects of collisional fragmentation. Including this additional grinding mechanism in a collision evolution model for the asteroid belt, we generate size-frequency distributions from either an accretional or an `Asteroids were born big' initial size-frequency distribution that are consistent with observations reported in Gladman et al. Rotational disruption is a new mechanism that must be included in all future collisional evolution models of asteroids.

  2. Main functions and taxonomic distribution of virulence genes in Brucella melitensis 16 M.

    PubMed

    Brambila-Tapia, Aniel Jessica Leticia; Armenta-Medina, Dagoberto; Rivera-Gomez, Nancy; Perez-Rueda, Ernesto

    2014-01-01

    Many virulence genes have been detected in attenuated mutants of Brucella melitensis 16 M; nevertheless, a complete report of these genes, including the main Cluster of Orthologous Groups (COG) represented as well as the taxonomical distribution among all complete bacterial and archaeal genomes, has not been analyzed. In this work a total of 160 virulence genes that have been reported in attenuated mutants in B. melitensis were included and analyzed. Additionally, we obtained 250 B. melitensis randomly selected genes as a reference group for the taxonomical comparisons. The COGs and the taxonomical distribution profile for 789 nonredundant bacterial and archaeal genomes were obtained and compared with the whole-genome COG distribution and with the 250 randomly selected genes, respectively. The main COGs associated with virulence genes corresponded to the following: intracellular trafficking, secretion and vesicular transport (U); cell motility (N); nucleotide transport and metabolism (F); transcription (K); and cell wall/membrane/envelope biogenesis (M). In addition, we found that virulence genes presented a higher proportion of orthologs in the Euryarchaeota and Proteobacteria phyla, with a significant decrease in Chlamydiae, Bacteroidetes, Tenericutes, Firmicutes and Thermotogae. In conclusion, we found that genes related to specific functions are more relevant to B. melitensis virulence, with the COG U the most significant. Additionally, the taxonomical distribution of virulence genes highlights the importance of these genes in the related Proteobacteria, being less relevant in distant groups of organisms with the exception of Euryarchaeota.

  3. Main Functions and Taxonomic Distribution of Virulence Genes in Brucella melitensis 16 M

    PubMed Central

    Brambila-Tapia, Aniel Jessica Leticia; Armenta-Medina, Dagoberto; Rivera-Gomez, Nancy; Perez-Rueda, Ernesto

    2014-01-01

    Many virulence genes have been detected in attenuated mutants of Brucella melitensis 16 M; nevertheless, a complete report of these genes, including the main Cluster of Orthologous Groups (COG) represented as well as the taxonomical distribution among all complete bacterial and archaeal genomes, has not been analyzed. In this work a total of 160 virulence genes that have been reported in attenuated mutants in B. melitensis were included and analyzed. Additionally, we obtained 250 B. melitensis randomly selected genes as a reference group for the taxonomical comparisons. The COGs and the taxonomical distribution profile for 789 nonredundant bacterial and archaeal genomes were obtained and compared with the whole-genome COG distribution and with the 250 randomly selected genes, respectively. The main COGs associated with virulence genes corresponded to the following: intracellular trafficking, secretion and vesicular transport (U); cell motility (N); nucleotide transport and metabolism (F); transcription (K); and cell wall/membrane/envelope biogenesis (M). In addition, we found that virulence genes presented a higher proportion of orthologs in the Euryarchaeota and Proteobacteria phyla, with a significant decrease in Chlamydiae, Bacteroidetes, Tenericutes, Firmicutes and Thermotogae. In conclusion, we found that genes related to specific functions are more relevant to B. melitensis virulence, with the COG U the most significant. Additionally, the taxonomical distribution of virulence genes highlights the importance of these genes in the related Proteobacteria, being less relevant in distant groups of organisms with the exception of Euryarchaeota. PMID:24964015

  4. 78 FR 10261 - Pipeline Safety: Information Collection Activities, Revision to Gas Distribution Annual Report

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-13

    ... Activities, Revision to Gas Distribution Annual Report AGENCY: Pipeline and Hazardous Materials Safety... Office of Management and Budget (OMB) approval for the revision of the gas distribution annual report... Report PHMSA intends to revise the gas distribution annual report (PHMSA F 7100.1-1, gas...

  5. DISTRIBUTION OF ACCRETING GAS AND ANGULAR MOMENTUM ONTO CIRCUMPLANETARY DISKS

    SciTech Connect

    Tanigawa, Takayuki; Ohtsuki, Keiji; Machida, Masahiro N.

    2012-03-01

    We investigate gas accretion flow onto a circumplanetary disk from a protoplanetary disk in detail by using high-resolution three-dimensional nested-grid hydrodynamic simulations, in order to provide a basis of formation processes of satellites around giant planets. Based on detailed analyses of gas accretion flow, we find that most of gas accretion onto circumplanetary disks occurs nearly vertically toward the disk surface from high altitude, which generates a shock surface at several scale heights of the circumplanetary disk. The gas that has passed through the shock surface moves inward because its specific angular momentum is smaller than that of the local Keplerian rotation, while gas near the midplane in the protoplanetary disk cannot accrete to the circumplanetary disk. Gas near the midplane within the planet's Hill sphere spirals outward and escapes from the Hill sphere through the two Lagrangian points L{sub 1} and L{sub 2}. We also analyze fluxes of accreting mass and angular momentum in detail and find that the distributions of the fluxes onto the disk surface are well described by power-law functions and that a large fraction of gas accretion occurs at the outer region of the disk, i.e., at about 0.1 times the Hill radius. The nature of power-law functions indicates that, other than the outer edge, there is no specific radius where gas accretion is concentrated. These source functions of mass and angular momentum in the circumplanetary disk would provide us with useful constraints on the structure and evolution of the circumplanetary disk, which is important for satellite formation.

  6. COLOR DEPENDENCE IN THE SIZE DISTRIBUTION OF MAIN BELT ASTEROIDS REVISITED

    SciTech Connect

    August, Tyler M.; Wiegert, Paul A.

    2013-06-15

    The size distribution of the asteroid belt is examined with 16956 main belt asteroids detected in data taken from the Canada-France-Hawaii Telescope Legacy Survey in two filters (g' and r'). The cumulative H (absolute magnitude) distribution is examined in both filters, and both match well to simple power laws down to H = 17, with slopes in rough agreement with those reported the literature. This implies that disruptive collisions between asteroids are gravitationally dominated down to at least this size, and probably sub-kilometer scales. The slopes of these distributions appear shallower in the outer belt than the inner belt, and the g' distributions appear slightly steeper than the r'. The slope shallowing in the outer belt may reflect a real compositional difference: the inner asteroid belt has been suggested to consist mostly of stony and/or metallic S-type asteroids, whereas carbonaceous C-types are thought to be more prevalent further from the Sun. No waves are seen in the size distribution above H = 15. Since waves are expected to be produced at the transition from gravitationally-dominated to internal strength-dominated collisions, their absence here may imply that the transition occurs at sub-kilometer scales, much smaller than the H = 17 (diameter {approx} 1.6 km) cutoff of this study.

  7. Color Dependence in the Size Distribution of Main Belt Asteroids Revisited

    NASA Astrophysics Data System (ADS)

    August, Tyler M.; Wiegert, Paul A.

    2013-06-01

    The size distribution of the asteroid belt is examined with 16956 main belt asteroids detected in data taken from the Canada-France-Hawaii Telescope Legacy Survey in two filters (g' and r'). The cumulative H (absolute magnitude) distribution is examined in both filters, and both match well to simple power laws down to H = 17, with slopes in rough agreement with those reported the literature. This implies that disruptive collisions between asteroids are gravitationally dominated down to at least this size, and probably sub-kilometer scales. The slopes of these distributions appear shallower in the outer belt than the inner belt, and the g' distributions appear slightly steeper than the r'. The slope shallowing in the outer belt may reflect a real compositional difference: the inner asteroid belt has been suggested to consist mostly of stony and/or metallic S-type asteroids, whereas carbonaceous C-types are thought to be more prevalent further from the Sun. No waves are seen in the size distribution above H = 15. Since waves are expected to be produced at the transition from gravitationally-dominated to internal strength-dominated collisions, their absence here may imply that the transition occurs at sub-kilometer scales, much smaller than the H = 17 (diameter ~ 1.6 km) cutoff of this study.

  8. Estimation of the main dill seeds odorant carvone by solid-phase microextraction and gas chromatography.

    PubMed

    Zawirska-Wojtasiak, Renata; Wasowicz, Erwin

    2002-10-01

    Solid-phase microextraction (SPME) was examined for its suitability for isolation of volatiles from seeds of dill in comparison with the traditional steam distillation procedure. Two main dill seeds volatiles, carvone and limonene, were taken into consideration. Two Supelco SPME fibers were used for the extraction: polyacrylic (PAc) and polydimethylsiloxane (PDMS). The time required to saturate the fibers was 3 min, while distillation took 3 h. Gas chromatography (GC) separation was reduced to 5 min by use of microcapillary column HP-5 cross-linked 5% Ph Me Siloxane. The standards of limonene and carvone were used to prepare calibration curves. PAc fiber responses were described by quadratic curves while PDMS responded linearly. Six varieties of dill were examined by distillation and SPME with both fibers. The good results were achieved for carvone by SPME-PDMS with significant regression between distillation and SPME. This compound can be measured in dill seeds samples within 10 min. The SPME-PDMS were also tested for its application to chiral resolution of carvone and limonene enantiomers in dill seeds oil. The enantiomeric separation was done with two chiral columns. The enantiomeric ratios measured by SPME were just the same as with distillation.

  9. Gas-leak localization using distributed ultrasonic sensors

    NASA Astrophysics Data System (ADS)

    Huseynov, Javid; Baliga, Shankar; Dillencourt, Michael; Bic, Lubomir; Bagherzadeh, Nader

    2009-03-01

    We propose an ultrasonic gas leak localization system based on a distributed network of sensors. The system deploys highly sensitive miniature Micro-Electro-Mechanical Systems (MEMS) microphones and uses a suite of energy-decay (ED) and time-delay of arrival (TDOA) algorithms for localizing a source of a gas leak. Statistical tools such as the maximum likelihood (ML) and the least squares (LS) estimators are used for approximating the source location when closed-form solutions fail in the presence of ambient background nuisance and inherent electronic noise. The proposed localization algorithms were implemented and tested using a Java-based simulation platform connected to four or more distributed MEMS microphones observing a broadband nitrogen leak from an orifice. The performance of centralized and decentralized algorithms under ED and TDOA schemes is analyzed and compared in terms of communication overhead and accuracy in presence of additive white Gaussian noise (AWGN).

  10. Distribution robotics in the gas industry: Issues and applications

    SciTech Connect

    Sweetwood, L.A.

    1986-01-01

    The new engineering field of ''Distribution Robotics'' is emerging in the gas industry. The purpose of this paper is to encourage the gas utility managers and engineers to take notice to this new technology and start factoring it into their planning strategies. The defined goal of distribution robotics is to improve the quality of service, lower operating costs, reduce work hazards, and perform in situ tasks. Applications of the distribution robotic system range from internal leak detection and repair to pipe condition assessment and cleaning; as stated, these applications are performed in a live system. To achieve the desired application missions, the robotic system requires robots of different designs along with appropriate tools, peripherals, and external support systems. The robot consists of several subsystems that allow motion, sensory perception, action and reaction, communication, and entering or existing the system. Each subsystem has several choices for robot configurations with advantages and trade-offs for the purpose, mode, range, and speed required by each mission. External support systems are required for a complete distribution robotic system. An external computer and human operator are needed as well as the physical hardware necessary to support a robot operation. Finally, issues raised by a distribution robotic system need consideration for proper planning. The major issues raised are robot miniaturization, obstacles, safety, coverage, and control.

  11. Gas distribution equipment in hydrogen service - Phase II

    NASA Technical Reports Server (NTRS)

    Jasionowski, W. J.; Huang, H. D.

    1980-01-01

    The hydrogen permeability of three different types of commercially available natural gas polyethylene pipes was determined. Ring tensile tests were conducted on permeability-exposed and as-received samples. Hydrogen-methane leakage experiments were also performed. The results show no selective leakage of hydrogen via Poiseuille, turbulent, or orifice flow (through leaks) on the distribution of blends of hydrogen and methane. The data collected show that the polyethylene pipe is 4 to 6 times more permeable to hydrogen than to methane.

  12. 3D modeling of gas/water distribution in water-bearing carbonate gas reservoirs: the Longwangmiao gas field, China

    NASA Astrophysics Data System (ADS)

    Ou, Chenghua; Li, ChaoChun; Ma, Zhonggao

    2016-10-01

    A water-bearing carbonate gas reservoir is an important natural gas resource being developed worldwide. Due to the long-term water/rock/gas interaction during geological evolution, complex gas/water distribution has formed under the superposed effect of sedimentary facies, reservoir space facies and gravity difference of fluid facies. In view of these challenges, on the basis of the conventional three-stage modeling method, this paper presents a modelling method controlled by four-stage facies to develop 3D model of a water-bearing carbonate gas reservoir. Key to this method is the reservoir property modelling controlled by two-stage facies, and the fluid property modelling controlled by another two-stage facies. The prerequisite of this method is a reliable database obtained from solid geological investigation. On the basis of illustrating the principles of the modelling method controlled by four-stage facies, this paper further implements systematically modeling of the heterogeneous gas/water distribution of the Longwangmiao carbonate formation in the Moxi-Gaoshiti area, Sichuan basin, China.

  13. GPS Constraints on the Spatial Distribution of Extension in the Ethiopian Highlands and Main Ethiopian Rift

    NASA Astrophysics Data System (ADS)

    Amere, Y. B.; Bendick, R. O.; Fisseha, S.; Lewi, E.; Reilinger, R. E.; King, R. W.; Kianji, G.

    2014-12-01

    27 campaign and 17 continuous GPS sites spanning the Ethiopian Highlands, Main Ethiopian Rift (MER), and Somali Platform in Ethiopia and Eritrea were measured for varying durations between 1995 and 2014. Velocities at these sites show that present day strain in NE Africa is not localized only in the Afar depression and MER system. Rather, velocities as high as 6 mm/yr relative to stable Nubia occur in the central Ethiopian highlands west of the rift bounding faults; the northern and southern Ethiopian highlands host velocities as high as 3 mm/yr. These approach the magnitude of Nubia-Somalia spreading accommodated within the rift itself of 6 + 1 mm/yr with an azimuth of N770E. The combination of distributed low strain rate deformation contiguous with higher strain rate plate boundary deformation is similar to that expressed in other tectonically active continental settings like Basin and Range and Tibetan Plateau.Keywords: deformation, localized, distributed, strain, stable Nubia.

  14. Distributed Fiber Optic Gas Sensing for Harsh Environment

    SciTech Connect

    Juntao Wu

    2008-03-14

    This report summarizes work to develop a novel distributed fiber-optic micro-sensor that is capable of detecting common fossil fuel gases in harsh environments. During the 32-month research and development (R&D) program, GE Global Research successfully synthesized sensing materials using two techniques: sol-gel based fiber surface coating and magnetron sputtering based fiber micro-sensor integration. Palladium nanocrystalline embedded silica matrix material (nc-Pd/Silica), nanocrystalline palladium oxides (nc-PdO{sub x}) and palladium alloy (nc-PdAuN{sub 1}), and nanocrystalline tungsten (nc-WO{sub x}) sensing materials were identified to have high sensitivity and selectivity to hydrogen; while the palladium doped and un-doped nanocrystalline tin oxide (nc-PdSnO{sub 2} and nc-SnO{sub 2}) materials were verified to have high sensitivity and selectivity to carbon monoxide. The fiber micro-sensor comprises an apodized long-period grating in a single-mode fiber, and the fiber grating cladding surface was functionalized by above sensing materials with a typical thickness ranging from a few tens of nanometers to a few hundred nanometers. GE found that the morphologies of such sensing nanomaterials are either nanoparticle film or nanoporous film with a typical size distribution from 5-10 nanometers. nc-PdO{sub x} and alloy sensing materials were found to be highly sensitive to hydrogen gas within the temperature range from ambient to 150 C, while nc-Pd/Silica and nc-WO{sub x} sensing materials were found to be suitable to be operated from 150 C to 500 C for hydrogen gas detection. The palladium doped and un-doped nc-SnO{sub 2} materials also demonstrated sensitivity to carbon monoxide gas at approximately 500 C. The prototyped fiber gas sensing system developed in this R&D program is based on wavelength-division-multiplexing technology in which each fiber sensor is identified according to its transmission spectra features within the guiding mode and cladding modes. The

  15. DISTRIBUTION OF FAINT ATOMIC GAS IN HICKSON COMPACT GROUPS

    SciTech Connect

    Borthakur, Sanchayeeta; Heckman, Timothy M.; Zhu, Guangtun; Yun, Min Su; Verdes-Montenegro, Lourdes; Braatz, James A.

    2015-10-10

    We present 21 cm H i observations of four Hickson Compact Groups (HCGs) with evidence for a substantial intragroup medium using the Robert C. Byrd Green Bank Telescope (GBT). By mapping H i emission in a region of 25′ × 25′ (140–650 kpc) surrounding each HCG, these observations provide better estimates of H i masses. In particular, we detected 65% more H i than that detected in the Karl G. Jansky Very Large Array (VLA) imaging of HCG 92. We also identify whether the diffuse gas has the same spatial distribution as the high surface brightness (HSB) H i features detected in the VLA maps of these groups by comparing the H i strengths between the observed and modeled masses based on VLA maps. We found that the H i observed with the GBT has a similar spatial distribution to the HSB structures in HCG 31 and HCG 68. Conversely, the observed H i distributions in HCG 44 and HCG 92 were extended and showed significant offsets from the modeled masses. Most of the faint gas in HCG 44 lies to the northeast–southwest region and in HCG 92 lies in the northwest region of their respective groups. The spatial and dynamical similarities between the total (faint+HSB) and the HSB H i indicate that the faint gas is of tidal origin. We found that the gas will survive ionization by the cosmic UV background and the escaping ionizing photons from the star-forming regions and stay primarily neutral for at least 500 Myr.

  16. Beam-Gas and Thermal Photon Scattering in the NLC Main Linac as a Source of Beam Halo (LCC-0051)

    SciTech Connect

    Tenenbaum, P

    2004-03-19

    Scattering of primary beam electrons off of residual gas molecules or blackbody radiation photons in the NLC main linac has been identified as a potential source of beam haloes which must be collimated in the beam delivery system. We consider the contributions from four scattering mechanisms: inelastic thermal-photon scattering, elastic beam-gas (Coulomb) scattering inelastic beam-gas (Bremsstrahlung) scattering, and atomic-electron scattering. In each case we develop the formalism necessary to estimate the backgrounds generated in the main linac, and determine the expected number of off-energy or large-amplitude particles from each process, assuming a main linac injection energy of 8 GeV and extraction energy of 500 GeV.

  17. Volcanic field elongation, vent distribution and tectonic evolution of continental rift: The Main Ethiopian Rift example

    NASA Astrophysics Data System (ADS)

    Mazzarini, Francesco; Le Corvec, Nicolas; Isola, Ilaria; Favalli, Massimiliano

    2015-04-01

    Magmatism and faulting operate in continental rifts and interact at a variety of scales, however their relationship is complex. The African rift, being the best example for both active continental rifting and magmatism, provides the ideal location to study the interplay between the two mechanisms. The Main Ethiopian Rift (MER), which connects the Afar depression in the north with the Turkana depression and Kenya Rift to the south, consists of two distinct systems of normal faults and its floor is scattered with volcanic fields formed by tens to several hundreds monogenetic, generally basaltic, small volcanoes and composite volcanoes and small calderas. The distribution of vents defines the overall shape of the volcanic field. Previous work has shown that the distribution of volcanic vents and the shape of a field are linked to its tectonic environment and its magmatic system. In order to distinguish the impact of each mechanism, we analyzed four volcanic fields located at the boundary between the central and northern MER, three of them (Debre Zeyit, Wonji and Kone) grew in the rift valley and one (Akaki) on the western rift shoulder. The elongation and shape of the fields were analyzed based on their vent distribution using the Principal Component Analysis (PCA), the Vent-to-Vent Distance (VVD), and the two dimensional symmetric Gaussian kernel density estimate methods. We extracted from these methods several parameters characterizing the spatial distribution of points (e.g., eccentricity (e), eigenvector index (evi), angular dispersion (Da)). These parameters allow to define at least three types of shape for volcanic fields: strong elongate (line and ellipse), bimodal/medium elongate (ellipse) and dispersed (circle) shapes. Applied to the natural example, these methods well differentiate each volcanic field. For example, the elongation of the field increases from shoulder to rift axis inversely to the angular dispersion. In addition, the results show that none of

  18. Truncated shifted pareto distribution in assessing size distribution of oil and gas fields

    SciTech Connect

    Houghton, J.C.

    1988-11-01

    The truncated shifted Pareto (TSP) distribution, a variant of the two-parameter Pareto distribution, in which one parameter is added to shift the distribution right and left and the right-hand side is truncated, is used to model size distributions of oil and gas fields for resource assessment. Assumptions about limits to the left-hand and right-hand side reduce the number of parameters to two. The TSP distribution has advantages over the more customary lognormal distribution because it has a simple analytic expression, allowing exact computation of several statistics of interest, has a J-shape, and has more flexibility in the thickness of the right-hand tail. Oil field sizes from the Minnelusa play in the Powder River Basin, Wyoming and Montana, are used as a case study. Probability plotting procedures allow easy visualization of the fit and help the assessment.

  19. Use of the truncated shifted Pareto distribution in assessing size distribution of oil and gas fields

    USGS Publications Warehouse

    Houghton, J.C.

    1988-01-01

    The truncated shifted Pareto (TSP) distribution, a variant of the two-parameter Pareto distribution, in which one parameter is added to shift the distribution right and left and the right-hand side is truncated, is used to model size distributions of oil and gas fields for resource assessment. Assumptions about limits to the left-hand and right-hand side reduce the number of parameters to two. The TSP distribution has advantages over the more customary lognormal distribution because it has a simple analytic expression, allowing exact computation of several statistics of interest, has a "J-shape," and has more flexibility in the thickness of the right-hand tail. Oil field sizes from the Minnelusa play in the Powder River Basin, Wyoming and Montana, are used as a case study. Probability plotting procedures allow easy visualization of the fit and help the assessment. ?? 1988 International Association for Mathematical Geology.

  20. Tidal Mixing and Buoyancy Advection: Joint Influences on Lobster Distribution in Coastal Maine

    NASA Astrophysics Data System (ADS)

    Brooks, D. A.

    2004-12-01

    The Eastern Maine Coastal Current (EMCC) flows southwestward from the mouth of the Bay of Fundy to Penobscot Bay on the central Maine coast. Maximum non-tidal surface speeds reach 20-30 cm/s about 20 km offshore during April-May when the outflow from the Saint John River is strongest. Vigorous tides cause strong vertical and horizontal mixing, so that dispersal of neutral particles is influenced both by advection and tidal mixing. To survive, planktonic lobsters carried southwestward in the surface flow must settle to a nearshore cobble substrate. Larvae hatched near the Bay of Fundy can be advected to the central coast in 2-3 weeks, roughly the time needed to reach settlement stage. Over the same period, transverse tidal mixing is sufficient to raise nearshore larval concentrations to about half that offshore in the axis of the EMCC. Both processes may be necessary to explain the observed lobster distribution, which exhibits a distinct maximum in the central coastal region. The seasonal development of the EMCC is also influenced by winds and the larger circulation of the Gulf of Maine. This work is part of a multidisciplinary synthesis study funded by the NOAA Coastal Ocean Program.

  1. The Historical Distribution of Main Malaria Foci in Spain as Related to Water Bodies

    PubMed Central

    Sousa, Arturo; García-Barrón, Leoncio; Vetter, Mark; Morales, Julia

    2014-01-01

    The possible connectivity between the spatial distribution of water bodies suitable for vectors of malaria and endemic malaria foci in Southern Europe is still not well known. Spain was one of the last countries in Western Europe to be declared free of malaria by the World Health Organization (WHO) in 1964. This study combines, by means of a spatial-temporal analysis, the historical data of patients and deceased with the distribution of water bodies where the disease-transmitting mosquitos proliferate. Therefore, data from historical archives with a Geographic Information System (GIS), using the Inverse Distance Weighted (IDW) interpolation method, was analyzed with the aim of identifying regional differences in the distribution of malaria in Spain. The reasons, why the risk of transmission is concentrated in specific regions, are related to worse socioeconomic conditions (Extremadura), the presence of another vector (Anopheles labranchiae) besides A. atroparvus (Levante) or large areas of water bodies in conditions to reproduce theses vectors (La Mancha and Western Andalusia). In the particular case of Western Andalusia, in 1913, the relatively high percentage of 4.73% of the surface, equal to 202362 ha, corresponds to wetlands and other unhealthy water bodies. These wetlands have been reduced as a result of desiccation policies and climate change such as the Little Ice Age and Global Climate Change. The comprehension of the main factors of these wetland changes in the past can help us interpret accurately the future risk of malaria re-emergence in temperate latitudes, since it reveals the crucial role of unhealthy water bodies on the distribution, endemicity and eradication of malaria in southern Europe. PMID:25101771

  2. Distribution of spin-axes longitudes and shape elongations of main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Cibulková, H.; Ďurech, J.; Vokrouhlický, D.; Kaasalainen, M.; Oszkiewicz, D. A.

    2016-11-01

    Context. Large all-sky surveys provide us with a lot of photometric data that are sparse in time (typically a few measurements per night) and can be potentially used for the determination of shapes and rotational states of asteroids. The method generally used to derive these parameters is the light curve inversion. However, for most asteroids their sparse data are not accurate enough to derive a unique model and the light curve inversion method is thus not very efficient. Aims: To fully utilize photometry sparse in time, we developed a new simplified model and applied it on the data from the Lowell photometric database. Our aim was to derive spin axis orientations and shape elongations of asteroids and to find out if there are some differences in distributions of these parameters for selected subpopulations. Methods: We modeled asteroids as geometrically scattering triaxial ellipsoids. Observed values of mean brightness and the dispersion of brightness were compared with computed values obtained from the parameters of the model, i.e., the ecliptical longitude λ and latitude β of the pole and the ratios a/b, b/c of axes of the ellipsoid. These parameters were optimized to get the best agreement with the observation. Results: We found that the distribution of λ for main-belt asteroids is not uniform and is dependent on the inclination of the orbit. Surprisingly, the nonuniformity of λ distribution is larger for asteroids residing on low-inclination orbits. We also studied distributions of a/b for several groups of asteroids and found that small asteroids (D< 25 km) are on average more elongated than large ones.

  3. 78 FR 34703 - Pipeline Safety: Information Collection Activities, Revision to Gas Distribution Annual Report

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ... Activities, Revision to Gas Distribution Annual Report AGENCY: Pipeline and Hazardous Materials Safety...) published a notice in the Federal Register of its intent to revise the gas distribution annual report (PHMSA... information collection is titled: ``Annual Report for Gas Distribution Pipeline Operators.'' Summary of...

  4. Process for forming a long gas turbine engine blade having a main wall with a thin portion near a tip

    SciTech Connect

    Campbell, Christian X; Thomaidis, Dimitrios

    2014-05-13

    A process is provided for forming an airfoil for a gas turbine engine involving: forming a casting of a gas turbine engine airfoil having a main wall and an interior cavity, the main wall having a wall thickness extending from an external surface of the outer wall to the interior cavity, an outer section of the main wall extending from a location between a base and a tip of the airfoil casting to the tip having a wall thickness greater than a final thickness. The process may further involve effecting movement, using a computer system, of a material removal apparatus and the casting relative to one another such that a layer of material is removed from the casting at one or more radial portions along the main wall of the casting.

  5. Integral gas seal for fuel cell gas distribution assemblies and method of fabrication

    DOEpatents

    Dettling, Charles J.; Terry, Peter L.

    1985-03-19

    A porous gas distribution plate assembly for a fuel cell, such as a bipolar assembly, includes an inner impervious region wherein the bipolar assembly has good surface porosity but no through-plane porosity and wherein electrical conductivity through the impervious region is maintained. A hot-pressing process for forming the bipolar assembly includes placing a layer of thermoplastic sealant material between a pair of porous, electrically conductive plates, applying pressure to the assembly at elevated temperature, and allowing the assembly to cool before removing the pressure whereby the layer of sealant material is melted and diffused into the porous plates to form an impervious bond along a common interface between the plates holding the porous plates together. The distribution of sealant within the pores along the surface of the plates provides an effective barrier at their common interface against through-plane transmission of gas.

  6. Method of fabricating an integral gas seal for fuel cell gas distribution assemblies

    DOEpatents

    Dettling, Charles J.; Terry, Peter L.

    1988-03-22

    A porous gas distribution plate assembly for a fuel cell, such as a bipolar assembly, includes an inner impervious region wherein the bipolar assembly has good surface porosity but no through-plane porosity and wherein electrical conductivity through the impervious region is maintained. A hot-pressing process for forming the bipolar assembly includes placing a layer of thermoplastic sealant material between a pair of porous, electrically conductive plates, applying pressure to the assembly at elevated temperature, and allowing the assembly to cool before removing the pressure whereby the layer of sealant material is melted and diffused into the porous plates to form an impervious bond along a common interface between the plates holding the porous plates together. The distribution of sealant within the pores along the surface of the plates provides an effective barrier at their common interface against through-plane transmission of gas.

  7. Main Power Distribution Unit for the Jupiter Icy Moons Orbiter (JIMO)

    NASA Technical Reports Server (NTRS)

    Papa, Melissa R.

    2004-01-01

    Around the year 2011, the Jupiter Icy Moons Orbiter (JIMO) will be launched and on its way to orbit three of Jupiter s planet-sized moons. The mission goals for the JIMO project revolve heavily around gathering scientific data concerning ingredients we, as humans, consider essential: water, energy and necessary chemical elements. The JIM0 is an ambitious mission which will implore propulsion from an ION thruster powered by a nuclear fission reactor. Glenn Research Center is responsible for the development of the dynamic power conversion, power management and distribution, heat rejection and ION thrusters. The first test phase for the JIM0 program concerns the High Power AC Power Management and Distribution (PMAD) Test Bed. The goal of this testing is to support electrical performance verification of the power systems. The test bed will incorporate a 2kW Brayton Rotating Unit (BRU) to simulate the nuclear reactor as well as two ION thrusters. The first module of the PMAD Test Bed to be designed is the Main Power Distribution Unit (MPDU) which relays the power input to the various propulsion systems and scientific instruments. The MPDU involves circuitry design as well as mechanical design to determine the placement of the components. The MPDU consists of fourteen relays of four different variations used to convert the input power into the appropriate power output. The three phase system uses 400 Vo1ts(sub L-L) rms at 1000 Hertz. The power is relayed through the circuit and distributed to the scientific instruments, the ION thrusters and other controlled systems. The mechanical design requires the components to be positioned for easy electrical wiring as well as allowing adequate room for the main buss bars, individual circuit boards connected to each component and power supplies. To accomplish creating a suitable design, AutoCAD was used as a drafting tool. By showing a visual layout of the components, it is easy to see where there is extra room or where the

  8. Direct Energy Exchange Enhancement in Distributed Injection Light Gas Launchers

    SciTech Connect

    Alger, T W; Finucane, R G; Hall, J P; Penetrante, B M; Uphaus, T M

    2000-04-06

    It is not widely acknowledged or appreciated that conventional, two-stage light-gas launchers do not efficiently apply their high breech pressures to the design intent: accelerating the projectile. Our objective in this project was to carry out the analysis, design, construction, and testing of a new class of launchers that will address this limitation. Our particular application is to expand the pressure range of the conventional, two-stage gas launcher to overlap and validate the pressure regimes previously attainable only with shock waves generated by nuclear explosions, lasers, or multistage conventional explosions. That is, these launchers would have the capability to conduct--in a laboratory setting--high-velocity-impact, equation-of-state (EOS) measurements at up to 2-TPa (20 Mbar) pressure levels in high-Z materials. Our design entailed a new class of distributed-injection, gas-dynamic launchers that are designed to use a boat-tail projectile to overcome the fundamental gas-expansion phenomena known as escape velocity (the Riemann limit). Our program included analytical, numerical, and experimental studies of the fast gas release flow technique that is central to the success of our approach. The analyses led us to believe that, in a typical configuration, the pressure will be effectively applied to the projectile in a time short relative to its few-microsecond traverse time; the experimental program we conducted during FY1999 supported these estimates. In addition, our program revealed dramatic increased efficiency in this process that was previously unknown to the launcher community. The most fundamental practical restrictions on the performance of any gas launcher are the ability of the launcher to (1) contain pressure in a reservoir, and (2) effectively apply that pressure to the base of a moving projectile. Our gas-release test-fixture experiments showed that our design was capable of applying nearly twice the pressure to the projectile that is

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

    NASA Astrophysics Data System (ADS)

    Kumar, Amit; Ram, Mangey

    2015-12-01

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

  10. Relation of adult size to movements and distribution of smallmouth bass in a central Maine Lake

    USGS Publications Warehouse

    Cole, M.B.; Moring, J.R.

    1997-01-01

    Forty-four smallmouth bass Micropterus dolomieu of three size-classes were radiotracked in Green Lake, Maine, during summer 1993 (10 June-1 September) to determine whether adult size influenced distribution and movement. Large smallmouth bass (>406 mm) used deep water (>8 m) more often than did small (248-279 mm) or medium-sized (305-356 mm) smallmouth bass during the late summer (15 July-1 September). Large smallmouth bass also were found at middepths (4-8 m) significantly more often than were small individuals during late summer. Small fish used cover more frequently than large ones during early summer (10 June-13 July). Both small and medium-sized individuals were associated with cover more frequently than large smallmouth bass were during the late summer. Small smallmouth bass exhibited significantly smaller summer total ranges than did large individuals, and mean active displacement differed among all three size-classes.

  11. In vivo metabolism of organophosphate flame retardants and distribution of their main metabolites in adult zebrafish.

    PubMed

    Wang, Guowei; Chen, Hanyan; Du, Zhongkun; Li, Jianhua; Wang, Zunyao; Gao, Shixiang

    2017-07-15

    Understanding the metabolism of chemicals as well as the distribution and depuration of their main metabolites in tissues are essential for evaluating their fate and potential toxicity in vivo. Herein, we investigated the metabolism of six typical organophosphate (OP) flame retardants (tripropyl phosphate (TPRP), tri-n-butyl phosphate (TNBP), tris(2-butoxyethyl) phosphate (TBOEP), tris(2-chloroethyl) phosphate (TCEP), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tri-p-cresyl phosphate (p-TCP)) in adult zebrafish in laboratory at three levels (0, 1/150 LC50 (environmentally relevant level), and 1/30 LC50 per OP analog). Twenty main metabolites were detected in the liver of OPs-exposed zebrafish using high resolution mass spectrometry (Q-TOF). The reaction pathways involving scission of the ester bond (hydrolysis), cleavage of the ether bond, oxidative hydroxylation, dechlorination, and coupling with glucuronic acid were proposed, and were further confirmed by the frontier electron density and point charge calculations. Tissue distribution of the twenty metabolites revealed that liver and intestine with the highest levels of metabolites were the most active organs for OPs biotransformation among the studied tissues of intestine, liver, roe, brain, muscle, and gill, which showed the importance of hepatobiliary system (liver-bile-intestine) in the metabolism and excretion of OPs in zebrafish. Fast depuration of metabolites from tissues indicated that the formed metabolites might be not persistent in fish, and easily released into water. This study provides comprehensive information on the metabolism of OPs in the tissue of zebrafish, which might give some hints for the exploration of their toxic mechanism in aquatic life.

  12. Spatial Distribution and Site-Specific Spraying of Main Sucking Pests of Elm Trees.

    PubMed

    Karimzadeh, R; Iranipour, S

    2016-11-09

    Elm trees are important landscape trees and sucking insects weaken the elm trees and produce large amounts of honeydew. The main objectives of this study were to identify main honeydew-producing pests of elm trees and do site-specific spraying against these pests. To map the spatial distribution of the sucking pests in the large scale, the study area was divided into 40 × 40 m grids and one tree was chosen randomly from each grid (a total of 55 trees). These trees were sampled twice a year in 2011 and 2012. Each sample was a 30-cm branch terminal. Eight samples were taken from each tree in four cardinal directions and two canopy levels. The number of sucking insects and leaves of each sample were counted and recorded. Spatial analysis of the data was carried out using geostatistics. Kriging was used for producing prediction maps. Insecticide application was restricted to the regions with populations higher than threshold. To identify within-tree distribution of the honeydew-producing pests, six and four elm trees were chosen in 2011 and 2012 respectively, and sampled weekly. These trees were sampled as described previously. European elm scale (EES), Gossyparia spuria (Modeer) and two species of aphids were the dominant honeydew-producing pests. The results revealed that the effects of direction, canopy level and their interactions on insect populations were not statistically significant (P < 0.05). Site-specific spraying decreased the amount of insecticides used by ca. 20%, while satisfactory control of the sucking pests and honeydew excretion was obtained. Considering the environmental and economic benefits of site-specific spraying, it is worth doing more complementary works in this area.

  13. Diel vertical distributions of the red tide dinoflagellate Alexandrium fundyense in the Gulf of Maine

    NASA Astrophysics Data System (ADS)

    Townsend, David W.; Bennett, Stephanie L.; Thomas, Maura A.

    2005-09-01

    Two 24-h experiments, designed to test whether the toxic dinoflagellate Alexandrium fundyense exhibited significant changes in vertical distribution, were performed in offshore waters of the Gulf of Maine in June 2000. Standard hydrocasts with a CTD/carousel water sampler package were made hourly on-station while following a drogue set at 25 m depth. Continuous measurements of T, S, and chlorophyll fluorescence were made on each down cast, and discrete water samples were collected at 5-m intervals from 55 m depth to the surface on the up cast, for analyses of extracted phytoplankton chlorophyll, inorganic nutrients and cell densities of Alexandrium In the first experiment we observed a bimodal vertical distribution of cells, with relatively high cell densities near the surface (<15 m depth) and a second peak of relatively high cell densities at depths between 25 and 40 m, coincident with the depth of the pycnocline and nitricline. Internal waves of 10-15 m amplitude appeared to exert control over the depth distribution of the deep population. Approximately 12 h into the first experiment, a relatively warm surface water mass with low Alexandrium cell densities intruded over the drogue station, leaving only the deep population. In the second experiment overall cell densities of Alexandrium were much lower, but again we observed initially a bimodal depth distribution of cells. As in the first experiment, the surface population effectively disappeared after a few hours, leaving only the deep population; in this case, however, there was some evidence of an initial downward movement of the surface population prior to its complete disappearance. Evidence for intrusion of a surface-water layer was not as clear in the second experiment as in the first. In addition to higher-frequency internal waves, as was observed in the first experiment, we also observed a low-frequency internal tidal wave of greater than 20 m amplitude that controlled the vertical distribution of the

  14. Reasons for crack nucleation in welded joints of main gas-pipelines after a long-term operation

    NASA Astrophysics Data System (ADS)

    Maruschak, P. O.; Bishchak, R. T.; Shlapak, L. S.; Panin, S. V.

    2017-02-01

    A crack of operational origin in the welded joint of the main gas pipeline is analyzed. The reasons for its nucleation and impact on technological microdefects that were formed earlier during the welding are found. Micromechanisms and stages of nucleation and propagation of the crack are investigated.

  15. The investigation of dangerous geological processes resulting in land subsidence while designing the main gas pipeline in South Yakutia

    NASA Astrophysics Data System (ADS)

    Strokova, L. A.; Ermolaeva, A. V.; Golubeva, V. V.

    2016-09-01

    The number of gas main accidents has increased recently due to dangerous geological processes in underdeveloped areas located in difficult geological conditions. The paper analyses land subsidence caused by karst and thermokarst processes in the right of way, reveals the assessment criteria for geological hazards and creates zoning schemes considering the levels of karst and thermorkarst hazards.

  16. The Sub-Kilometer Asteroid Diameter Survey II: The debiased size distribution of main belt asteroids

    NASA Astrophysics Data System (ADS)

    Jedicke, R.; Gladman, B.; Davis, D.; Petit, J.-M.

    2011-10-01

    The Sub-Kilometer Asteroid Diameter Survey (SKADS, [1]) imaged ˜8.6 square degrees of sky and detected 1277 main belt asteroids to a limiting magnitude of R˜23 (at which the efficiency is 50%). SKADS was performed in both V and R filters and allows a probabilistic assignment of an albedo, and therefore diameter, to each object. By planting synthetic objects directly into the images we have determined the moving object detection efficiency as a function of their rate and direction of motion and their apparent magnitude on each of the six survey nights. The surveying pattern was designed to provide recovery of the asteroids over intervals of >6 days and therefore provides a good orbit, distance and absolute magnitude for each of the objects. We have performed a high-resolution, high-accuracy simulation of the multi-night surveying procedure to compute the observational selection effects as a function of semi-major axis, eccentricity, inclination and absolute magnitude (see Figure 1). We will present the results of this simulation and provide the observationally corrected distributions of main belt objects as a function of their orbital parameters, absolute magnitude and diameter.

  17. Seismicity distribution and locking depth along the Main Marmara Fault, Turkey

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, J.; Karabulut, H.; Lengliné, O.; Bouchon, M.

    2016-03-01

    The seismicity along the Main Marmara Fault (MMF) below the Marmara Sea is analyzed during the 2007-2012 period to provide insights on the recent evolution of this important regional seismic gap. High precision locations show that seismicity is strongly varying along strike and depth providing fine details of the fault behavior that are inaccessible from geodetic observations. The activity strongly clusters at the regions of transition between basins. The Central basin shows significant seismicity located below the shallow locking depth inferred from GPS measurements. Its b-value is low and the average seismic slip is high. All observations are consistent with a deep creep of this segment. On the contrary, the Kumburgaz basin at the center of the fault shows sparse seismicity with the hallmarks of a locked segment. In the eastern Marmara Sea, the seismicity distribution along the Princes Island segment in the Cinarcik basin, is consistent with the geodetic locking depth of 10 km and a low contribution to the regional seismic energy release. The assessment of the locked segment areas provide an estimate of the magnitude of the main forthcoming event to be about 7.3 assuming that the rupture will not enter significantly within creeping domains.

  18. Some design aspects of plastics gas distribution pipeline systems

    SciTech Connect

    Wolters, M.

    1988-01-01

    Plastics gas distribution systems are in use in the Netherlands for more than 25 years. Three different plastics pipe materials have been used, i.e. polyethylene (PE), rigid PVC and impact modified PVC (PVC/CPE). The gas authority must consider the many and varied factors which will influence the choice of a particular material. Each material has its characteristic properties which will determine its field of application and the design concepts of the system. Since this will be a compromise between material properties and design, the advantages and disadvantages of the system must be examined for each specific area of application. Factors which will influence the choice are a.o.: external loading conditions (soil and traffic loads, third party damage, etc.); internal loading (max. allowable internal pressure, gas composition); the material properties like long-term strength, ductility, stiffness, resistance to rapid crack propagation; jointing methods; materials costs and laying costs. These above mentioned factors are discussed for the plastics pipe materials in operation in the Netherlands.

  19. Seismicity along the Main Marmara Fault, Turkey: from space-time distribution to repeating events

    NASA Astrophysics Data System (ADS)

    Schmittbuhl, Jean; Karabulut, Hayrullah; Lengliné, Olivier; Bouchon, Michel

    2016-04-01

    The North Anatolian Fault (NAF) poses a significant hazard for the large cities surrounding the Marmara Sea region particularly the megalopolis of Istanbul. Indeed, the NAF is presently hosting a long unruptured segment below the Sea of Marmara. This seismic gap is approximately 150 km long and corresponds to the Main Marmara Fault (MMF). The seismicity along the Main Marmara Fault (MMF) below the Marmara Sea is analyzed here during the 2007-2012 period to provide insights on the recent evolution of this important regional seismic gap. High precision locations show that seismicity is strongly varying along strike and depth providing fine details of the fault behavior that are inaccessible from geodetic inversions. The activity strongly clusters at the regions of transition between basins. The Central basin shows significant seismicity located below the shallow locking depth inferred from GPS measurements. Its b-value is low and the average seismic slip is high. Interestingly we found also several long term repeating earthquakes in this domain. Using a template matching technique, we evidenced two new families of repeaters: a first family that typically belongs to aftershock sequences and a second family of long lasting repeaters with a multi-month recurrence period. All observations are consistent with a deep creep of this segment. On the contrary, the Kumburgaz basin at the center of the fault shows sparse seismicity with the hallmarks of a locked segment. In the eastern Marmara Sea, the seismicity distribution along the Princes Island segment in the Cinarcik basin, is consistent with the geodetic locking depth of 10km and a low contribution to the regional seismic energy release. The assessment of the locked segment areas provide an estimate of the magnitude of the main forthcoming event to be about 7.3 assuming that the rupture will not enter significantly within creeping domains.

  20. The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment

    NASA Astrophysics Data System (ADS)

    Tacchella, Sandro; Dekel, Avishai; Carollo, C. Marcella; Ceverino, Daniel; DeGraf, Colin; Lapiner, Sharon; Mandelker, Nir; Primack Joel, R.

    2016-04-01

    Using cosmological simulations, we address the properties of high-redshift star-forming galaxies (SFGs) across their main sequence (MS) in the plane of star formation rate (SFR) versus stellar mass. We relate them to the evolution of galaxies through phases of gas compaction, depletion, possible replenishment, and eventual quenching. We find that the high-SFR galaxies in the upper envelope of the MS are compact, with high gas fractions and short depletion times (`blue nuggets'), while the lower SFR galaxies in the lower envelope have lower central gas densities, lower gas fractions, and longer depletion times, consistent with observed gradients across the MS. Stellar-structure gradients are negligible. The SFGs oscillate about the MS ridge on time-scales ˜0.4tHubble (˜1 Gyr at z ˜ 3). The propagation upwards is due to gas compaction, triggered, e.g. by mergers, counter-rotating streams, and/or violent disc instabilities. The downturn at the upper envelope is due to central gas depletion by peak star formation and outflows while inflow from the shrunken gas disc is suppressed. An upturn at the lower envelope can occur once the extended disc has been replenished by fresh gas and a new compaction can be triggered, namely as long as the replenishment time is shorter than the depletion time. The mechanisms of gas compaction, depletion, and replenishment confine the SFGs to the narrow (±0.3 dex) MS. Full quenching occurs in massive haloes (Mvir > 1011.5 M⊙) and/or at low redshifts (z < 3), where the replenishment time is long compared to the depletion time, explaining the observed bending down of the MS at the massive end.

  1. Market hub technology in the domestic natural gas distribution system. [Natural gas market center or hub

    SciTech Connect

    Glicken, J.

    1992-09-01

    This document describes a panel discussion held on March 18, 1992 as part of a conference entitled Market Hub Technology'' . The purpose of the conference was to stimulate dialogue among various segments of the natural gas industry on the technology limits of an economic policy issue that has the potential to significantly alter the structure and functioning of the natural gas industry. Attendees included key US gas industry representatives, Federal Energy Regulatory Commission (FERC) commissioners, and others. The conference explored the concept of market centers, or hubs, and related technologies. It covered the technology currently available for the establishment of an integrated system of physical market hubs, and explored technology requirements for the further development of useful and efficient hubs. The discussion identified two primary barriers to the acceptance and implementation of a market center distribution system for natural gas. The first barrier is the potential change in the configuration of the market such a system would introduce and the resistance various industry segments would mount to such change. The second is the lack of industry standardization in the physical and business infrastructures.

  2. Effect of Dreissena mussels on the distribution of zooplankton as exemplified by the Main Kakhovka Canal

    SciTech Connect

    Grigorovich, I.A.; Shevtsova, L.V.

    1995-06-01

    In summer the abundance of zooplankton in the Main Kakhovka Canal varied in the range of 1,500-18,500 indiv.m{sup -3}, with a biomass of 15-240 mg m{sup -3}. From the upper reach of the canal to the end, the zooplankton become less diverse and there is a decrease in both abundance and biomass. In the initial sections of the canal, copepods predominated, owing to their considerable influxes from other sources, i.e., Kakhovka Reservoir. Whereas in the second half of the canal, the dominant complexes of zooplankton changed and consisted primarily of cladocerans and Dreissena veligers. With high abundance of Dreissena polymorpha (Pallas) and D. bugensis (Andrusov) (mean biomass was 4.2 kg m{sup -2}), with the maximum ca. 17.8 kg m{sup -2}, mussels had a significant effect on the spatial distribution of planktonic invertebrates. In different areas of the canal the measurable quantitive replenishment of zooplankton was proceeded by planktonic larvae of Dreissena. Being active filterers, Dreissena mollusks undermine food resources of filter-feeding zooplankton by accelerating sedimentation of suspended matter, including organic substances, by a factor of 1.4-3.0. Dreissena can control zooplankton density by consumption of some of the species. With predominating rotifers and juveniles cladocerans in the plankton, the total abundance of zooplankton influenced by Dreissena bugensis had decreased by 53% after 12 h, whereas the amount of dominant species, Euchlanis dilatata and Bosmina longirostris, had declined respectively by 92% and 64%. Dreissena individuals 14-18 mm long, are the predominant size group of mussels in the Main Kakhovka Canal and can filter off planktonic invertebrates with body lengths between 20 and 400 m. Zooplankton species of such size can pass through the bronchial siphon of Dreissena and so they are vulnerable to consumption by mussels. There is an inverse relationship between the biomass of zooplankton and the biomass of adult Dreissena mussels.

  3. Spatial distribution of pelagic fish larvae in the northern main basin of Lake Huron

    USGS Publications Warehouse

    Roseman, Edward F.; O'Brien, Timothy P.

    2013-01-01

    Larval fish occurrence in inshore and offshore zones in the northern main basin of Lake Huron was assessed during 2007 as part of a larger ecological examination of Lake Huron foodwebs and habitats. Day and night collections using neuston and conical nets at inshore (1.5–15 m depths) and offshore (37 and 91 m depths) locations at De Tour and Hammond Bay to assess the abundance, phenology, and spatial distribution of pelagic ichthyoplankton during spring and early summer were made. In general, densities of larval fishes were higher at De Tour than Hammond Bay during daytime neuston net collections, with the exception of Longnose Sucker, which were only collected at Hammond Bay. Lake Whitefish, Burbot, and Rainbow Smelt dominated inshore catches in early spring with Cisco, Deepwater Sculpin, Emerald Shiner, Bloater, Slimy Sculpin, Ninespine Stickleback, and Yellow Perch larvae also collected. Nighttime nearshore and offshore sampling revealed that Rainbow Smelt and Burbot larvae were present in relatively high abundances compared to inshore densities. Concentrations of larvae of deepwater demersal fishes such as Lake Whitefish and Deepwater Sculpin suggest that inshore zones in northern Lake Huron are important nursery habitats emphasizing a critical production and recruitment linkage between inshore and deepwater zones.

  4. Distribution of spin axes and shape elongations of main-belt asteroids

    NASA Astrophysics Data System (ADS)

    Cibulkova, Helena; Durech, Josef; Vokrouhlicky, David; Kaasalainen, Mikko; Oszkiewicz, Dagmara Anna

    2016-10-01

    Photometric data that are sparse in time (typically few measurements per night over ~15 years) are a potential source of information about shapes and rotational states of asteroids. However, currently available data are usually not accurate enough to derive a unique sidereal rotation period and corresponding shape model by the lightcurve inversion method. To fully utilize sparse-in-time data, we have developed a new simplified model that provides an approximate solution for the orientation of the spin axis (λ, β) and ratios of axes of the ellipsoid, a/b, b/c (asteroids are modelled as geometrically scattering triaxial ellipsoids). The observed values of mean brightness (over one apparition) and the dispersion of brightness are compared with values computed from the model parameters (λ, β, a, b, setting c=1) which are optimized to get the best agreement. The model was applied on the data from Lowell photometric database. We found that the distribution of pole ecliptic longitude λ is nonuniform and that this nonuniformity is larger for asteroids with low inclination of their orbits. The second main result is that small asteroids (D<25 km) are on average more elongated (a/b ~ 1.6) than the large ones (for D>50 km the mean value of a/b is 1.3).

  5. 78 FR 6318 - SourceGas Distribution LLC; Notice of Petition for Rate Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Petition for Rate Approval Take notice that on January 15, 2013, SourceGas Distribution LLC (SourceGas) filed a rate election pursuant...

  6. 78 FR 41398 - SourceGas Distribution LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Filing Take notice that on June 27, 2013, SourceGas Distribution LLC (SourceGas) filed a Rate Election and revised Statement of...

  7. 77 FR 28374 - SourceGas Distribution LLC; Notice of Compliance Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Compliance Filing Take notice that on April 30, 2012, SourceGas Distribution LLC (SourceGas) filed a revised Statement of Operating...

  8. CAIS standard manual. System number 24. Natural gas distribution system

    SciTech Connect

    1995-04-28

    At this installation the list of facilities to be surveyed, including infrastructure, will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a related list of components. Detailed observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Natural Gas Distribution System.

  9. Cross-sensitivity of metal oxide gas sensor to ambient temperature and humidity: Effects on gas distribution mapping

    NASA Astrophysics Data System (ADS)

    Kamarudin, K.; Bennetts, V. H.; Mamduh, S. M.; Visvanathan, R.; Yeon, A. S. A.; Shakaff, A. Y. M.; Zakaria, A.; Abdullah, A. H.; Kamarudin, L. M.

    2017-03-01

    Metal oxide gas sensors have been widely used in robotics application to perform remote and mobile gas sensing. However, previous researches have indicated that this type of sensor technology is cross-sensitive to environmental temperature and humidity. This paper therefore investigates the effects of these two factors towards gas distribution mapping and gas source localization domains. A mobile robot equipped with TGS2600 gas sensor was deployed to build gas distribution maps of indoor environment, where the temperature and humidity varies. The results from the trials in environment with and without gas source indicated that there is a strong relation between the fluctuation of the mean and variance map with respect to the variations in the temperature and humidity maps.

  10. Role of unloading and filtration of gas in the development of main cracks in coal seams

    NASA Astrophysics Data System (ADS)

    Feldman, E. P.; Kalugina, N. A.; Meln'ik, T. N.

    2017-01-01

    The development of main cracks in coal seams due to rapid unloading is analyzed using the methods of theoretical physics. A fracture criterion and a criterion for the time to fracture of an area at the edge of a coal seam are obtained.

  11. Seasonal Distribution and Movements of Atlantic and Shortnose Sturgeon in the Penobscot River Estuary, Maine

    USGS Publications Warehouse

    Zydlewski, Joseph; Fernandes, Stephen J.; Zydlewski, Gayle B.; Wippelhauser, Gail S.; Kinnison, Michael T.

    2016-01-01

    Relatively little is known about the distribution and seasonal movement patterns of shortnose sturgeon Acipenser brevirostrum and Atlantic sturgeon Acipenser oxyrinchus oxyrinchus occupying rivers in the northern part of their range. During 2006 and 2007, 40 shortnose sturgeon (66–113.4 cm fork length [FL]) and 8 Atlantic sturgeon (76.2–166.2 cm FL) were captured in the Penobscot River, Maine, implanted with acoustic transmitters, and monitored using an array of acoustic receivers in the Penobscot River estuary and Penobscot Bay. Shortnose sturgeon were present year round in the estuary and overwintered from fall (mid-October) to spring (mid-April) in the upper estuary. In early spring, all individuals moved downstream to the middle estuary. Over the course of the summer, many individuals moved upstream to approximately 2 km of the downstream-most dam (46 river kilometers [rkm] from the Penobscot River mouth [rkm 0]) by August. Most aggregated into an overwintering site (rkm 36.5) in mid- to late fall. As many as 50% of the tagged shortnose sturgeon moved into and out of the Penobscot River system during 2007, and 83% were subsequently detected by an acoustic array in the Kennebec River, located 150 km from the Penobscot River estuary. Atlantic sturgeon moved into the estuary from the ocean in the summer and concentrated into a 1.5-km reach. All Atlantic sturgeon moved to the ocean by fall, and two of these were detected in the Kennebec River. Although these behaviors are common for Atlantic sturgeon, regular coastal migrations of shortnose sturgeon have not been documented previously in this region. These results have important implications for future dam removals as well as for rangewide and river-specific shortnose sturgeon management.

  12. Numerical solutions of ideal quantum gas dynamical flows governed by semiclassical ellipsoidal-statistical distribution

    PubMed Central

    Yang, Jaw-Yen; Yan, Chih-Yuan; Diaz, Manuel; Huang, Juan-Chen; Li, Zhihui; Zhang, Hanxin

    2014-01-01

    The ideal quantum gas dynamics as manifested by the semiclassical ellipsoidal-statistical (ES) equilibrium distribution derived in Wu et al. (Wu et al. 2012 Proc. R. Soc. A 468, 1799–1823 (doi:10.1098/rspa.2011.0673)) is numerically studied for particles of three statistics. This anisotropic ES equilibrium distribution was derived using the maximum entropy principle and conserves the mass, momentum and energy, but differs from the standard Fermi–Dirac or Bose–Einstein distribution. The present numerical method combines the discrete velocity (or momentum) ordinate method in momentum space and the high-resolution shock-capturing method in physical space. A decoding procedure to obtain the necessary parameters for determining the ES distribution is also devised. Computations of two-dimensional Riemann problems are presented, and various contours of the quantities unique to this ES model are illustrated. The main flow features, such as shock waves, expansion waves and slip lines and their complex nonlinear interactions, are depicted and found to be consistent with existing calculations for a classical gas. PMID:24399919

  13. Real gas properties and Space Shuttle Main Engine fuel turbine performance prediction

    NASA Technical Reports Server (NTRS)

    Harloff, G. J.

    1987-01-01

    The H2/H2O mixture thermodynamic and transport properties variations for the Space Shuttle Main Engine (SSME) fuel turbine over a range of temperatures and pressures are examined. The variation of molecular viscosity, specific heat at constant pressure, and Prandtl number for the hydrogen/steam mixture are fitted using polynominal relationships for future turbine performance use. The mixture property variations are calculated using GASP and WASP computer programs. The air equivalent performance of the SSME fuel turbine is computed.

  14. THE MOLECULAR GAS CONTENT OF z = 3 LYMAN BREAK GALAXIES: EVIDENCE OF A NON-EVOLVING GAS FRACTION IN MAIN-SEQUENCE GALAXIES AT z > 2

    SciTech Connect

    Magdis, Georgios E.; Rigopoulou, D.; Daddi, E.; Sargent, M.; Elbaz, D.; Gobat, R.; Tan, Q.; Aussel, H.; Feruglio, C.; Charmandaris, V.; Dickinson, M.; Reddy, N.

    2012-10-10

    We present observations of the CO[J = 3 {yields} 2] emission toward two massive and infrared luminous Lyman break galaxies (LBGs) at z = 3.21 and z = 2.92, using the IRAM Plateau de Bure Interferometer, placing first constraints on the molecular gas masses (M{sub gas}) of non-lensed LBGs. Their overall properties are consistent with those of typical (main-sequence) galaxies at their redshifts, with specific star formation rates {approx}1.6 and {approx}2.2 Gyr{sup -1}, despite their large infrared luminosities (L{sub IR} Almost-Equal-To (2-3) Multiplication-Sign 10{sup 12} L{sub Sun }) derived from Herschel. With one plausible CO detection (spurious detection probability of 10{sup -3}) and one upper limit, we investigate the evolution of the molecular gas-to-stellar mass ratio (M{sub gas}/M{sub *}) with redshift. Our data suggest that the steep evolution of M{sub gas}/M{sub *} of normal galaxies up to z {approx} 2 is followed by a flattening at higher redshifts, providing supporting evidence for the existence of a plateau in the evolution of the specific star formation rate at z > 2.5.

  15. Development of colorless distributed combustion for gas turbine application

    NASA Astrophysics Data System (ADS)

    Arghode, Vaibhav Kumar

    Colorless Distributed Combustion (CDC) is investigated for gas turbine engine application due to its benefit for ultra-low pollutant emission, improved pattern factor, low noise emission, stable combustion and low pressure drop, alleviation of combustion instabilities and increased life of turbine blades with less air cooling requirements. The CDC is characterized by discrete and direct injection of fuel and air at high velocity and the reaction zone is stabilized due to controlled aerodynamics inside the combustor and wider (radially) shear layer mixing. Mixing between the injected air and product gases to form hot and diluted oxidant is required followed by rapid mixing with the fuel. This results in distributed reaction zone instead of a concentrated flame front as observed in conventional diffusion flames and hence, to avoid hot spot regions and provide reduced NOx and CO emissions. The focus of this dissertation is to develop and demonstrate CDC for application to stationary gas turbine combustors which generally operate at thermal intensity of 15MW/m3-atm. However, higher thermal intensity is desirable to reduce hardware costs due to smaller weight and volume of the combustors. Design of high thermal intensity CDC combustor requires careful control of critical parameters, such as, gas recirculation, fuel/oxidizer mixing and residence time characteristics via careful selection of different air and fuel injection configurations to achieve desirable combustion characteristics. This dissertation examines sequential development of low emission colorless distributed combustor operating from thermal intensity of 5MW/m3-atm up to 198MW/m3-atm. Initially, various fuel and air injection configurations were investigated at a low thermal intensity of 5MW/m 3-atm. Further investigations were performed for a simpler combustor having single air and fuel injection ports for medium thermal intensity range of 28-57MW/m3-atm. Among the flow configurations investigated, reverse

  16. Energy conservation: The main factor for reducing greenhouse gas emissions in the former Soviet Union

    SciTech Connect

    Bashmakov, I.A.; Chupyatov, V.P.

    1991-12-01

    The energy intensity of the former Soviet Union is more than twice that of other market economics in similar stages of economic development. Low energy efficiency in the Soviet Union has contributed significantly to global carbon and other greenhouse gas emissions. The technological potential for energy conservation in the former Soviet Union is the largest in the world. The inefficiencies of the previously command-system economy, however, have provided little incentive for conserving energy. The present transition to a market-based economy should encourage the incorporation of energy-efficiency improvements in order for the former Soviet Union to successfully lower its energy intensity. There are several obstacles that limit implementing energy conservation: for example, energy prices and discount rates influence the volume of investment in energy efficiency. Nevertheless, cost-effective measures for energy conservative do exist even in the most energy-intensive sectors of the Soviet economy and should form the core of any energy conservation program. The overall cost-effective potential for carbon savings in the former Soviet Union is estimated to be 280 to 367 million tons of carbon per year by the year 2005, or 23 to 29 percent of 1988 energy-related emissions.

  17. Distribution and toxicity of Alexandrium ostenfeldii (Dinophyceae) in the Gulf of Maine, USA

    NASA Astrophysics Data System (ADS)

    Gribble, Kristin E.; Keafer, Bruce A.; Quilliam, Michael A.; Cembella, Allan D.; Kulis, David M.; Manahan, Abigail; Anderson, Donald M.

    2005-09-01

    Alexandrium ostenfeldii is a thecate, mixotrophic dinoflagellate recently linked to a novel suite of toxins called spirolides. This study provides the first description of the regional distribution of A. ostenfeldii in the Gulf of Maine (GOM), and the first report and analysis of spirolide toxicity in A. ostenfeldii in waters south of Nova Scotia. Morphological examination of cells in field samples and of clonal cultures isolated from several stations in the GOM confirmed the presence of A. ostenfeldii. A genus-specific antibody probe, and an A. ostenfeldii species-specific oligonucleotide probe labeled these cells; a probe specific for the North American A. fundyense/tamarense/catenella species complex did not label A. ostenfeldii cells. Cell size ranged from 20 to nearly 90 μm, and most cells contained food vacuoles, with a total vacuole size from 1 to 48 μm. The hydrographic forcings controlling the distribution of A. ostenfeldii in the GOM are quite similar to those acting on the A. fundyense population at the same time of the year. The highest concentrations of A. ostenfeldii were observed nearshore, to the east of Penobscot Bay, at times with an offshore-turning branch of high cell concentration to the south of Penobscot Bay. Casco Bay appears to be an area of accumulation for A. ostenfeldii cells advected toward shore from the core of the population to the northeast. Concentrations of A. ostenfeldii were generally higher at the surface than deeper, except at locations where the pooling of lower-salinity water at the surface may have led to the subduction of the population flowing in from the east. PSP toxins were detected in field populations containing A. ostenfeldii and A. fundyense, but not in A. ostenfeldii cultures isolated from the GOM. Spirolide toxins were found in 36 of 60 field samples. More than 83% of samples containing A. ostenfeldii cells had one or more of spirolide congeners A, B, C2 and D2. The total concentration of spirolides per cell at

  18. Distribution of sulfur deposition near a wellbore in a sour gas reservoir

    NASA Astrophysics Data System (ADS)

    Hu, Jinghong; Yang, Xuefeng; He, ShunLi; Zhao, Jinzhou

    2013-02-01

    Elemental sulfur precipitates from sour gas when reservoir pressure and temperature decrease. Sulfur deposition in a formation may significantly reduce the inflow performance of sour gas wells. This paper develops a micro-mechanical migration model and experiments which describe the law of sulfur precipitation, plugging and distribution near a wellbore. Based on the analysis of the sulfur deposition law and micro-mechanical migration theory, elemental sulfur mechanical models in pores are presented. The critical velocity of sulfur is calculated and the rule of precipitated sulfur distribution near a wellbore is deduced. Reservoir cores and supersaturated sour gas are utilized to observe sulfur precipitation and plugging in sulfur damage experiments, and the main influential factor is analysed. According to the models and experimental results, precipitated sulfur can decrease reservoir permeability. The liquid bridge force is the most important factor to affect reservoir permeability due to sulfur deposition. Precipitated sulfur cannot be carried away from pores if the liquid bridge force is considered; the critical velocity increases as the diameter of the sulfur particles increases, which may cause serious formation damage. Moreover, it can be seen from the results that the biggest volume of sulfur deposition does not occur at the bottom but near the bottom of a borehole. These results can be used to describe the profile of dynamic sulfur deposition and help a reservoir engineer to develop a plan for removing the sulfur near a wellbore.

  19. 75 FR 5244 - Pipeline Safety: Integrity Management Program for Gas Distribution Pipelines; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-02

    ... implement integrity management programs. In addition to a minor correction in terminology, this document...: Integrity Management Program for Gas Distribution Pipelines; Correction AGENCY: Pipeline and...

  20. Study of a distributed feedback diode laser based hygrometer combined Herriot-gas cell and waterless optical components

    NASA Astrophysics Data System (ADS)

    Wei, Yubin; Chang, Jun; Lian, Jie; Wang, Qiang; Wei, Wei

    2016-09-01

    A distributed feedback diode laser (DFB-DL) based hygrometer combined with a long-path-length Herriot gas cell and waterless optical components was proposed and investigated. The main function of this sensor was to simultaneously improve the measurement reliability and resolution. A comparison test between a 10-cm normal transmission-type gas cell and a 3-m Herriot gas cell was carried out to demonstrate the improvement. Reliability improvement was achieved by influence suppression of water vapor inside optical components (WVOC) through combined action of the Herriot gas cell and waterless optical components. The influence of WVOC was suppressed from 726 ppmv to 25 ppmv using the Herriot gas cell. Moreover, combined with waterless optical components, the influence of WVOC was further suppressed to no more than 4 ppmv. Resolution improvement from 11.7 ppmv to 0.32 ppmv was achieved mainly due to the application of the long-path-length Herriot gas cell. The results show that the proposed sensor has a good performance and considerable potential application in gas sensing, especially when probed gas possibly permeates into optical components.

  1. Blimp Robot for Three-Dimensional Gas Distribution Mapping in Indoor Environment

    NASA Astrophysics Data System (ADS)

    Ishida, Hiroshi

    2009-05-01

    Mobile robots equipped with gas sensors can be used for automated measurement tasks including odor trail following, gas source localization, and gas distribution mapping. This article reports on the development of a blimp robot for mapping three-dimensional gas distribution in indoor environments. The blimp robot is programmed to fly randomly so that its trajectory covers everywhere in the given indoor environment. The blimp is equipped with gas sensors to measure gas concentrations and an ultrasonic sonar to measure the height from the floor. The measured data are transmitted to an external PC via a wireless communication module. At the same time, a camera placed on the floor takes a picture of the blimp, and its location is recorded with the gas sensor responses. The experimental results indicate that the blimp robot is effective in mapping three-dimensional gas concentration distribution in indoor environments.

  2. Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury

    SciTech Connect

    Wendel, Mark W; Riemer, Bernie; Abdou, Ashraf A

    2012-01-01

    ABSTRACT Pressure waves created in liquid mercury pulsed spallation targets have been shown to induce cavitation damage on the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, measuring such a population in mercury is difficult since it is opaque and the mercury is involved in a turbulent flow. Ultrasonic measurements have been attempted on these types of flows, but the flow noise can interfere with the measurement, and the results are unverifiable and often unrealistic. Recently, a flow loop was built and operated at Oak Ridge National Labarotory to assess the capability of various bubbler designs to deliver an adequate population of bubbles to mitigate cavitation damage. The invented diagnostic technique involves flowing the mercury with entrained gas bubbles in a steady state through a horizontal piping section with a glass-window observation port located on the top. The mercury flow is then suddenly stopped and the bubbles are allowed to settle on the glass due to buoyancy. Using a bright-field illumination and a high-speed camera, the arriving bubbles are detected and counted, and then the images can be processed to determine the bubble populations. After using this technique to collect data on each bubbler, bubble size distributions were built for the purpose of quantifying bubbler performance, allowing the selection of the best bubbler options. This paper presents the novel procedure, photographic technique, sample visual results and some example bubble size distributions. The best bubbler options were subsequently used in proton beam irradiation tests performed at the Los Alamos National Laboratory. The cavitation damage results from the irradiated test plates in contact with the mercury are available for correlation with the bubble populations. The most effective mitigating population can now be designed into prototypical geometries for implementation into

  3. Potential for Lyme disease in Maine: deer survey of distribution of Ixodes dammini, the tick vector.

    PubMed Central

    Smith, R P; Rand, P W; Lacombe, E H

    1990-01-01

    A survey of deer brought to tagging stations at 24 sites in Main revealed the presence of the deer tick, Ixodes dammini, on 5.1 percent of deer. Ticks were found almost exclusively on deer from southwest coastal sites in the state. The potential for endemic Lyme disease in coastal Maine merits further study. PMID:2305920

  4. Distributed and decentralized state estimation in gas networks as distributed parameter systems.

    PubMed

    Ahmadian Behrooz, Hesam; Boozarjomehry, R Bozorgmehry

    2015-09-01

    In this paper, a framework for distributed and decentralized state estimation in high-pressure and long-distance gas transmission networks (GTNs) is proposed. The non-isothermal model of the plant including mass, momentum and energy balance equations are used to simulate the dynamic behavior. Due to several disadvantages of implementing a centralized Kalman filter for large-scale systems, the continuous/discrete form of extended Kalman filter for distributed and decentralized estimation (DDE) has been extended for these systems. Accordingly, the global model is decomposed into several subsystems, called local models. Some heuristic rules are suggested for system decomposition in gas pipeline networks. In the construction of local models, due to the existence of common states and interconnections among the subsystems, the assimilation and prediction steps of the Kalman filter are modified to take the overlapping and external states into account. However, dynamic Riccati equation for each subsystem is constructed based on the local model, which introduces a maximum error of 5% in the estimated standard deviation of the states in the benchmarks studied in this paper. The performance of the proposed methodology has been shown based on the comparison of its accuracy and computational demands against their counterparts in centralized Kalman filter for two viable benchmarks. In a real life network, it is shown that while the accuracy is not significantly decreased, the real-time factor of the state estimation is increased by a factor of 10.

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

    SciTech Connect

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

    2009-08-15

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

  6. 78 FR 13661 - National Fuel Gas Distribution Corporation; Notice of Petition for Rate Approval

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-28

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission National Fuel Gas Distribution Corporation; Notice of Petition for Rate Approval Take notice that on February 12, 2013, National Fuel Gas Distribution Corporation filed...

  7. 77 FR 10490 - SourceGas Distribution LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Filing Take notice that on February 14, 2012, SourceGas Distribution LLC submitted a revised baseline filing of their Statement of...

  8. 75 FR 51032 - National Fuel Gas Distribution Corporation; Notice of Baseline Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission National Fuel Gas Distribution Corporation; Notice of Baseline Filing August 12, 2010. Take notice that on August 10, 2010, National fuel Gas Distribution Corporation submitted...

  9. 40 CFR Table W - 7 of Subpart W of Part 98-Default Methane Emission Factors for Natural Gas Distribution

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Methane Emission Factors for Natural Gas Distribution W Table W Protection of Environment ENVIRONMENTAL... Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-7 Table W-7 of Subpart W of Part 98—Default Methane Emission Factors for Natural Gas Distribution Natural gas distribution Emission factor...

  10. 40 CFR Table W - 7 of Subpart W of Part 98-Default Methane Emission Factors for Natural Gas Distribution

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Methane Emission Factors for Natural Gas Distribution W Table W Protection of Environment ENVIRONMENTAL... Natural Gas Systems Definitions. Pt. 98, Subpt. W, Table W-7 Table W-7 of Subpart W of Part 98—Default Methane Emission Factors for Natural Gas Distribution Natural gas distribution Emission factor...

  11. SOIL ALUMINUM DISTRIBUTION IN THE NEAR-STREAM ZONE AT THE BEAR BROOK WATERSHED IN MAINE

    EPA Science Inventory

    Near-stream and upslope soil chemical properties were analyzed to infer linkages between soil and surface water chemistry at the Bear Brook Watershed in Maine [BBWM]. Organic and mineral soil samples were collected along six 20 m transects perpendicular to the stream and one 200 ...

  12. The distribution of warm ionized gas in NGC 891

    NASA Technical Reports Server (NTRS)

    Rand, Richard J.; Kulkarni, Shrinivas R.; Hester, J. Jeff

    1990-01-01

    Narrow-band imaging is presented of the edge-on spiral NGC 891 in the H-alpha and S II 6716, 6731 A forbidden lines. Emission from H II regions confined to the plane of the galaxy and from diffuse gas up to about 4 kpc off the plane is readily detected. The full radial extent of the diffuse emission in the plane is about 30 kpc. NGC 891 is found to have a surface density of diffuse ionized gas twice the Galactic value, a thicker ionized gas layer, and a larger surface density of ionized gas relative to neutral gas. These are interpreted as consequences of a relatively high level of star formation in this galaxy. Other star formation tracers indicate the same conclusion. Many vertical H-alpha filaments, or 'worms,' extending to over 2 kpc off the plane of the galaxy are seen. These worms are interpreted in terms of chimney models for the interstellar media of spirals.

  13. Estimation of current density distribution of PAFC by analysis of cell exhaust gas

    SciTech Connect

    Kato, S.; Seya, A.; Asano, A.

    1996-12-31

    To estimate distributions of Current densities, voltages, gas concentrations, etc., in phosphoric acid fuel cell (PAFC) stacks, is very important for getting fuel cells with higher quality. In this work, we leave developed a numerical simulation tool to map out the distribution in a PAFC stack. And especially to Study Current density distribution in the reaction area of the cell, we analyzed gas composition in several positions inside a gas outlet manifold of the PAFC stack. Comparing these measured data with calculated data, the current density distribution in a cell plane calculated by the simulation, was certified.

  14. [Vertical distribution of main species captured by tuna longline fishery in the southeast Pacific Ocean].

    PubMed

    Zhang, Yan-bo; Dai, Xiao-jie; Zhu, Jiang-feng; Gao, Chun-xia; Wu, Feng; Zheng, Xiao-chun

    2015-03-01

    Information of vertical distribution of longline-hook species is important for the development of effective measures to mitigate bycatch, and very helpful for better understanding of the oceanic ecosystem structure and implementation of ecosystem-based fisheries management. Based on depth data of longline hook and capture hook position of pelagic species, collected by on board scientific observer in the southeast Pacific Ocean from September 2013 to January 2014, shoaling rate of longline hook and vertical distribution of 14 pelagic species were analyzed. The results showed that the relative shoaling rate range of longline hook was 8.9% - 17.1%, and the average relative shoaling rate was 13.5%. The depth ranges of 14 capture species were different. The species with the deepest depth was Opah (Lampris guttatus), and the species with the shallowest depth was skipjack (Katsuwonus pelamis). Except for yellowfin tuna (Thunnus albacares) and striped marlin (Tetrapturus audax), the mean depth and depth distributions of bycatch species were significantly different from that of the targeted albacore tuna (Thunnus alalunga).

  15. Ant diversity and distribution (Hymenoptera: Formicidae) throughout Maine lowbush blueberry fields in Hancock and Washington Counties.

    PubMed

    Choate, Beth; Drummond, Francis A

    2012-04-01

    A 6-yr survey (2003-2008) identifying the ant fauna present in Maine lowbush blueberry fields was conducted in Washington and Hancock Counties. Pitfall trapping, leaf litter, and hand collections, as well as protein and sugar baits were used to characterize the resident ant community in this habitat. Estimates of faunal richness as impacted by the blueberry crop stage (pruned or fruit-bearing), methods of pest management (grower standard, reduced-risk, or organic), and location within fields (middle, edge, or forested perimeters) were determined. In total, 42 species were collected from blueberry fields, comprising five subfamilies and 15 genera. Myrmica sculptilis Francoeur, Myrmica americana Weber, and Formica exsectoides Forel were the three most abundant species. Formica ulkei Emery, Myrmecina americana Emery, and Leptothorax canadensis Provancher represent new species records for Maine. Ants were most diverse in organic fields, and along the edge and within the wooded areas surrounding fields. Results suggest insecticide application reduces ant diversity.

  16. [Species composition and main populations spatial distribution pattern in Korean pine broadleaved forest in Xiaoxing' An Mountains of Northeast China].

    PubMed

    Hou, Hong-Ya; Wang, Li-Hai

    2013-11-01

    Taking the Korean pine broadleaved forest in Liangshui Nature Reserve of Heilongjiang Province, Northeast China as test object, this paper studied the species composition and diameter class structure, and by using point pattern analysis, analyzed the spatial distribution pattern and spatial association of the main populations. In the Reserve, there were a total of 16 species with diameter greater than 1 cm in tree layer, and great differences were observed in the densities of main populations. Coniferous trees such as Pinus koraiensis and Abies nephrolepis were dominant. The diameter class structure of the populations presented as an inverse "J" curve, indicating a good regeneration across the community. The main populations were mostly in aggregated distribution pattern, except that the P. koraiensis populations at the scales of 19-21 m and 44 m as well as the Acer tegmentosum populations close to the largest research scale were in random distribution. The P. koraiensis populations at all research scales were approximately in random distribution, and had the minimum aggregation. A. nephrolepis, Tilia amurensis, and A. tegmentosum populations all presented a random distribution trend. Except that the P. koraiensis and A. nephrolepis at 2-3 m scale and the A. nephrolepis and A. tegmentosum populations at 37-81 m scale had significant positive association, no significant associations were observed between other populations. All the tree species presented an overall non-significant positive association.

  17. Sand volume and distribution on the paraglacial inner continental shelf of the northwestern Gulf of Maine

    USGS Publications Warehouse

    Kelley, J.T.; Dickson, S.M.; Belknap, D.F.; Barnhardt, W.A.; Barber, D.C.

    2003-01-01

    In an extensive program of side-scan sonar and seismic reflection profiling, bottom sampling and vibracoring, we have mapped the western Gulf of Maine between Canada and Massachusetts, from the shoreline to the 100 m isobath. The purpose of the program was, in part, to locate and evaluate sand resources on the inner shelf. Surficial sand occurs on only 7% of this formerly glaciated region, and most is located seaward of southern Maine's large beaches in Wells Embayment, Saco Bay, and off Cape Small. Sand deposits occur 1) at the lowstand position of sea level, between 50 and 60 m depth, 2) on parts of the inner shelf between 50 m and the shoreface, and 3) in the shoreface. A paleodelta of the region's largest river, the Kennebec, occurs off Cape Small. Elsewhere, the lowstand deposits are thinner (5 m of relief on the inner shelf and contain large quantities of material. The shoreface contains the greatest concentration of sand in each of the regions. A wedge-shaped deposit of sand overlies estuarine muddy sands in each area and is inferred to have formed during a slowdown in the rate of sea-level rise between 7.5 and 9.5 ka. The volume of shoreface sand varies from less than 60 million cubic meters in Saco Bay to more than 300 million cubic meters off Cape Small, and is loosely correlated with the erosional state of adjacent beaches.

  18. Potential effects of climate change on the distribution range of the main silicate sinker of the Southern Ocean

    PubMed Central

    Pinkernell, Stefan; Beszteri, Bánk

    2014-01-01

    Fragilariopsis kerguelensis, a dominant diatom species throughout the Antarctic Circumpolar Current, is coined to be one of the main drivers of the biological silicate pump. Here, we study the distribution of this important species and expected consequences of climate change upon it, using correlative species distribution modeling and publicly available presence-only data. As experience with SDM is scarce for marine phytoplankton, this also serves as a pilot study for this organism group. We used the maximum entropy method to calculate distribution models for the diatom F. kerguelensis based on yearly and monthly environmental data (sea surface temperature, salinity, nitrate and silicate concentrations). Observation data were harvested from GBIF and the Global Diatom Database, and for further analyses also from the Hustedt Diatom Collection (BRM). The models were projected on current yearly and seasonal environmental data to study current distribution and its seasonality. Furthermore, we projected the seasonal model on future environmental data obtained from climate models for the year 2100. Projected on current yearly averaged environmental data, all models showed similar distribution patterns for F. kerguelensis. The monthly model showed seasonality, for example, a shift of the southern distribution boundary toward the north in the winter. Projections on future scenarios resulted in a moderately to negligibly shrinking distribution area and a change in seasonality. We found a substantial bias in the publicly available observation datasets, which could be reduced by additional observation records we obtained from the Hustedt Diatom Collection. Present-day distribution patterns inferred from the models coincided well with background knowledge and previous reports about F. kerguelensis distribution, showing that maximum entropy-based distribution models are suitable to map distribution patterns for oceanic planktonic organisms. Our scenario projections indicate

  19. The characteristics of gravity and magnetic fields and the distribution of tight sandstone gas in the eastern Ordos Basin, China

    NASA Astrophysics Data System (ADS)

    Yuan, Bingqiang; Zhang, Huaan; Zhang, Chunguan; Xu, Haihong; Yan, Yunkui

    2016-04-01

    In order to perform gas exploration and determine the distribution pattern of gas in the Yanchang Oil Field in the eastern part of the North Shaanxi Slope, Ordos Basin, China, gravity and magnetic survey data were systemically collated, processed and interpreted in combination with the drilling data and recent seismic data. The genesis of gravity and magnetic anomalies and the relationship between the characteristics of the gravity and magnetic fields and known gas distribution were explored in order to predict the favourable exploration targets for gas. Gravity anomalies resulted both from the lateral variation in density of the basement rock and lateral lithologic transformation in the sedimentary cover. The regional magnetic anomalies were mainly caused by the basement metamorphic rocks and the residual magnetic anomalies may reflect the amount and general location of the volcanic materials in the overlying strata. The residual gravity and magnetic anomalies generated by high-density sandstone and high content of volcanics in the gas reservoir of the upper Paleozoic distorted and deformed the anomaly curves when they were stacked onto the primary background anomaly. The gas wells were generally found to be located in the anomaly gradient zones, or the distorted part of contour lines, and the flanks of high and low anomalies, or the transitional zones between anomaly highs and lows. The characteristics of gravity and magnetic fields provide significant information that can be used for guidance when exploring the distribution of gas. Based on these characteristics, five favourable areas for gas exploration were identified; these are quasi-equally spaced like a strip extending from the southeast to the northwest.

  20. Distribution and speciation of mercury in surficial sediments from main mangrove wetlands in China.

    PubMed

    Ding, Z H; Liu, J L; Li, L Q; Lin, H N; Wu, H; Hu, Z Z

    2009-09-01

    The purpose of this study was to establish the distribution, speciation and bioavailability of mercury in mangrove sediments. A systemic survey of surficial sediments from 13 mangrove wetlands of China was carried out. Hg concentrations ranged from 2.3-903.6ngg(-1), with an average value of 189.4ngg(-1). Of the 13 areas surveyed, the Hg content in sediments was similar to background levels in 6 areas but was much higher in the other seven areas. Hg levels were affected by natural and anthropogenic factors, including terrestrial pollutants, geomorphic properties, and indirectly by economic status. Hg levels were positively correlated with organic matter, pH, and silt and clay fractions, but Hg was negatively correlated with sand fraction. In most mangrove wetlands, Hg existed primarily in the form of volatile Hg. Hg is easily bioaccumulated in mangrove wetlands and may be the natural source of Hg emissions to the atmosphere.

  1. Numerical analysis of flow non-uniformity in the hot gas manifold of the Space Shuttle main engine

    NASA Technical Reports Server (NTRS)

    Thoenes, J.; Robertson, S. J.; Ratliff, A. W.; Anderson, P. G.

    1985-01-01

    Three-dimensional viscous flow in a conceptual hot gas manifold (HGM) for the Space Shuttle Main Engine High Pressure Fuel Turbopump (SSME HPFTP) was numerically analyzed. A finite difference scheme was used to solve the Navier-Stokes equations. The exact geometry of the SSME HGM was modeled using boundary fitted curvilinear coordinates and the General Interpolants Method (GIM) code. Slight compressibility of the subsonic flow was modeled using a linearized equation of state with artificial compressibility. A time relaxation method was used to obtain a steady state solution. The feasibility and potential usefulness of computational methods in assisting the design of SSME components which involves the flow of fluids within complex geometrical shapes is demonstrated.

  2. Dissolved methane in rising main sewer systems: field measurements and simple model development for estimating greenhouse gas emissions.

    PubMed

    Foley, Jeff; Yuan, Zhiguo; Lant, Paul

    2009-01-01

    At present, the potential generation of methane in wastewater collection systems is ignored under international greenhouse gas (GHG) accounting protocols, despite recent reports of substantial dissolved methane formation in sewers. This suggests that the current national GHG inventories for wastewater handling systems are likely to be underestimated for some situations. This study presents a new catalogue of field data on methane formation in rising main sewerage systems and proposes an empirically-fitted, theoretical model to predict dissolved methane concentrations, based upon the independent variables of pipeline geometry (i.e. surface area to volume ratio, A/V) and hydraulic retention time (HRT). Systems with longer HRT and/or larger A/V ratios are shown to have higher dissolved methane concentrations. This simple predictive model provides a means for water authorities to estimate the methane emissions from other pressurised sewerage systems of similar characteristics.

  3. Computational Study of Main Mechanisms for Gas-Phase Decomposition of 1,1- and 1,2-Dinitroethane

    NASA Astrophysics Data System (ADS)

    Tsyshevsky, Roman V.; Aristov, Ilia V.; Chachkov, Denis V.; Shamov, Alexander G.; Khrapkovskii, Grigorii M.

    2010-10-01

    The gas-phase enthalpies of formation of 1,1- and 1,2-dinitroethane and corresponding radical products were calculated using G3B3, CBS-QB3 composite methods and DFT B3LYP level of theory with various basis sets. The enthalpies of the C-N, C-C bonds dissociation and activation enthalpies for HONO elimination were also calculated and compared with available experimental data. It was found that G3B3 calculations do provide a reasonable way to tackle the problem of the decomposition channels of 1,1- and 1,2-dinitroethane. Four main mechanisms for gas-phase decomposition of 1,1- and 1,2-dinitroethane were studied using G3B3 model chemistry. HONO elimination seems to be the most favorable mechanism for the decomposition of 1,2-dinitroethane. However, the difference in energies of the HONO elimination and C-N homolytic bond cleavage in 1,1-dinitroethane does not allow to favor any of these channels, especially at the working temperature. Gauche conformation of 1,2-dinitroethane is calculated to be the lowest-energy minimum.

  4. Small turbines in distributed utility application: Natural gas pressure supply requirements

    SciTech Connect

    Goldstein, H.L.

    1996-05-01

    Implementing distributed utility can strengthen the local distribution system and help avoid or delay the expense of upgrading transformers and feeders. The gas turbine-generator set is an attractive option based on its low front-end capital cost, reliable performance at unmanned stations, and environmental performance characteristics. This report assesses gas turbine utilization issues from a perspective of fuel supply pressure requirements and discusses both cost and operational factors. A primary operational consideration for siting gas turbines on the electric distribution system is whether the local gas distribution company can supply gas at the required pressure. Currently available gas turbine engines require gas supply pressures of at least 150 pounds per square inch gauge, more typically, 250 to 350 psig. Few LDCs maintain line pressure in excess of 125 psig. One option for meeting the gas pressure requirements is to upgrade or extend an existing pipeline and connect that pipeline to a high-pressure supply source, such as an interstate transmission line. However, constructing new pipeline is expensive, and the small volume of gas required by the turbine for the application offers little incentive for the LDC to provide this service. Another way to meet gas pressure requirements is to boost the compression of the fuel gas at the gas turbine site. Fuel gas booster compressors are readily available as stand-alone units and can satisfactorily increase the supply pressure to meet the turbine engine requirement. However, the life-cycle costs of this equipment are not inconsequential, and maintenance and reliability issues for boosters in this application are questionable and require further study. These factors may make the gas turbine option a less attractive solution in DU applications than first indicated by just the $/kW capital cost. On the other hand, for some applications other DU technologies, such as photovoltaics, may be the more attractive option.

  5. Tectonic Controls on Gas Hydrate Distribution off SW Taiwan

    NASA Astrophysics Data System (ADS)

    Berndt, C.; Chi, W. C.; Jegen, M. D.; Muff, S.; Hölz, S.; Lebas, E.; Sommer, M.; Lin, S.; Liu, C. S.; Lin, A. T.; Klaucke, I.; Klaeschen, D.; Chen, L.; Kunath, P.; McIntosh, K. D.; Feseker, T.

    2015-12-01

    The northern part of the South China Sea is characterized by wide-spread occurrence of bottom simulating reflectors (BSR), indicating the presence of marine gas hydrates. Because the area covers both the tectonically inactive passive margin and the northern termination of the Manila Trench subduction zone while sediment input is broadly similar, this area provides an excellent opportunity to study the influence of tectonic processes on the dynamics of gas hydrate systems. Long-offset multi-channel seismic data show that movement along thrust faults and blind thrust faults caused anticlinal ridges on the active margin, while faults are absent on the passive margin. This coincides with high-hydrate saturations derived from ocean bottom seismometer data and controlled source electromagnetic data, and conspicuous high-amplitude reflections in P-Cable 3D seismic data above the BSR in the anticlinal ridges of the active margin. On the contrary, all geophysical evidence for the passive margin points to normal- to low-hydrate saturations. Geochemical analysis of gas samples collected at seep sites on the active margin show methane with heavy δ13C isotope composition, while gas collected on the passive margin shows highly depleted (light) carbon isotope composition. Thus, we interpret the passive margin as a typical gas hydrate province fuelled by biogenic production of methane and the active margin gas hydrate system as a system that is fuelled not only by biogenic gas production but also by additional advection of thermogenic methane from the subduction system. The location of the highest gas hydrate saturations in the hanging wall next to the thrust faults suggests that the thrust faults represent pathways for the migration of methane. Our findings suggest that the most promising gas hydrate occurrences for exploitation of gas hydrate as an energy source may be found in the core of the active margin roll over anticlines immediately above the BSR and that high

  6. A SIMPLE PHYSICAL MODEL FOR THE GAS DISTRIBUTION IN GALAXY CLUSTERS

    SciTech Connect

    Patej, Anna; Loeb, Abraham

    2015-01-01

    The dominant baryonic component of galaxy clusters is hot gas whose distribution is commonly probed through X-ray emission arising from thermal bremsstrahlung. The density profile thus obtained has been traditionally modeled with a β-profile, a simple function with only three parameters. However, this model is known to be insufficient for characterizing the range of cluster gas distributions and attempts to rectify this shortcoming typically introduce additional parameters to increase the fitting flexibility. We use cosmological and physical considerations to obtain a family of profiles for the gas with fewer parameters than the β-model but which better accounts for observed gas profiles over wide radial intervals.

  7. Distribution and effects of shallow gas on bulk estuarine sediment properties

    USGS Publications Warehouse

    Hill, J.M.; Halka, J.P.; Conkwright, R.; Koczot, K.; Coleman, S.

    1992-01-01

    Gas bubble are present in sediments covering approximately 30% of the main stem of Chesapeake Bay, with bubbles occurring at the sediment-water interface in 18% of the main stem sediments. This biogenic gas is found either in the sediments in the lower salinity reaches of the Bay, or confined to sediments which overline infilled palaeodrainage channels formed during the Wisconsinan low sea level stand (approximately 18 ka). Gas associated with the old drainage network does not correlate with present bathymetry or sedimentological patterns. Some differences between the gas-charged and gas-free sediments are: (1) gas-charged sediments have water contents 10-20% higher than comparable gas-free cores; (2) organic matter is better presented with depth in the gas-charged sediments (upwards of 60% more at one depth); (3 monosulphides are dominant sulphide mineral phase within the gas-charged sediments, comprising over 40% of the total sulphur. Within the gas-free sediments monosulphides are significant only near the sediment-water interface and rapidly become negligible with depth, and; (4) cores of gas-charged sediments are highly colour-banded due to preservation of sulphide mineral variations, while gas-free cores are diagenetically altered to pyrite. ?? 1992.

  8. The distribution of warm ionized gas in NGC 891

    SciTech Connect

    Rand, R.J.; Kulkarni, S.R.; Hester, J.J. Infrared Processing and Analysis Center, Pasadena, CA )

    1990-03-01

    Narrow-band imaging is presented of the edge-on spiral NGC 891 in the H-alpha and S II 6716, 6731 A forbidden lines. Emission from H II regions confined to the plane of the galaxy and from diffuse gas up to about 4 kpc off the plane is readily detected. The full radial extent of the diffuse emission in the plane is about 30 kpc. NGC 891 is found to have a surface density of diffuse ionized gas twice the Galactic value, a thicker ionized gas layer, and a larger surface density of ionized gas relative to neutral gas. These are interpreted as consequences of a relatively high level of star formation in this galaxy. Other star formation tracers indicate the same conclusion. Many vertical H-alpha filaments, or 'worms,' extending to over 2 kpc off the plane of the galaxy are seen. These worms are interpreted in terms of chimney models for the interstellar media of spirals. 19 refs.

  9. The distribution of ionized gas in early-type galaxies

    NASA Astrophysics Data System (ADS)

    Buson, L. M.; Sadler, E. M.; Zeilinger, W. W.; Bertin, G.; Bertola, F.; Danzinger, J.; Dejonghe, H.; Saglia, R. P.; de Zeeuw, P. T.

    1993-12-01

    We present and discuss H-alpha+(N II) imaging observations of fifteen nearby elliptical and SO galaxies with extended optical emission lines. The morphology of the emitting regions suggests that the ionized gas usually lies in a disk which is often geometrically decoupled from the stellar body, as expected in a triaxial galaxy. The presence of a gaseous disk makes these galaxies suitable for testing their gravitational field in a straightforward way. The presence of dust in many of the disks, together with the observed morphological properties, suggests that the ionized gas in most of these galaxies is more closely associated with the cold Interstellar Medium (ISM) than with the hot X-ray component. The mass of ionized gas in the galaxies studied here is typically 10-100 times that in a 'normal' early-type galaxy of similar optical luminosity. These appear to be galaxies where an unusually high fraction of the cold gas has been ionized, rather than unusually gas-rich systems in an overall sense. The extra ionizing source may be related to an active nucleus, since the continuum radio emission from these galaxies is typically 10-15 times more powerful than in 'normal' ellipticals of the smae optical luminosity.

  10. Nucleopolyhedrovirus detection and distribution in terrestrial, freshwater, and marine habitats of Appledore Island, Gulf of Maine.

    PubMed

    Hewson, Ian; Brown, Julia M; Gitlin, Shari A; Doud, Devin F

    2011-07-01

    Viruses in aquatic ecosystems comprise those produced by both autochthonous and allochthonous host taxa. However, there is little information on the diversity and abundance of viruses of allochthonous origin, particularly from non-anthropogenic sources, in freshwater and marine ecosystems. We investigated the presence of nucleopolyhedroviruses (NPV) (Baculovirus), which commonly infect terrestrial lepidopteran taxa, across the landscape of Appledore Island, Gulf of Maine. PCR and qPCR primers were developed around a 294-bp fragment of the polyhedrin (polH) gene, which is the major constituent protein of NPV multivirion polyhedral occlusion bodies. polH was successfully amplified from several aquatic habitats, and recovered polH sequences were most similar to known lepidopteran NPV. Using quantitative PCR designed around a cluster of detected sequences, we detected polH in Appledore Island soils, supratidal freshwater ponds, nearshore sediments, near- and offshore plankton, and in floatsam. This diverse set of locations suggests that NPVs are widely dispersed along the terrestrial--marine continuum and that free polyhedra may be washed into ponds and eventually to sea. The putative hosts of detected NPVs were webworms (Hyphantria sp.) which form dense nests in late summer on the dominant Appledore Island vegetation (Prunus virginiana). Our data indicate that viruses of terrestrial origin (i.e., allochthonous viruses) may be dispersed widely in coastal marine habitats. The dispersal of NPV polH and detection within offshore net plankton (>64 μm) demonstrates that terrestrial viruses may interact with larger particles and plankton of coastal marine ecosystem, which further suggests that viral genomic information may be transported between biomes.

  11. Evaluating gas transfer velocity parameterizations using upper ocean radon distributions

    NASA Astrophysics Data System (ADS)

    Bender, Michael L.; Kinter, Saul; Cassar, Nicolas; Wanninkhof, Rik

    2011-02-01

    Sea-air fluxes of gases are commonly calculated from the product of the gas transfer velocity (k) and the departure of the seawater concentration from atmospheric equilibrium. Gas transfer velocities, generally parameterized in terms of wind speed, continue to have considerable uncertainties, partly because of limited field data. Here we evaluate commonly used gas transfer parameterizations using a historical data set of 222Rn measurements at 105 stations occupied on Eltanin cruises and the Geosecs program. We make this evaluation with wind speed estimates from meteorological reanalysis products (from National Centers for Environmental Prediction and European Centre for Medium-Range Weather Forecasting) that were not available when the 22Rn data were originally published. We calculate gas transfer velocities from the parameterizations by taking into account winds in the period prior to the date that 222Rn profiles were sampled. Invoking prior wind speed histories leads to much better agreement than simply calculating parameterized gas transfer velocities from wind speeds on the day of sample collection. For individual samples from the Atlantic Ocean, where reanalyzed winds agree best with observations, three similar recent parameterizations give k values for individual stations with an rms difference of ˜40% from values calculated using 222Rn data. Agreement of basin averages is much better. For the global data set, the average difference between k constrained by 222Rn and calculated from the various parameterizations ranges from -0.2 to +0.9 m/d (average, 2.9 m/d). Averaging over large domains, and working with gas data collected in recent years when reanalyzed winds are more accurate, will further decrease the uncertainties in sea-air fluxes.

  12. Observed oil and gas field size distributions: A consequence of the discovery process and prices of oil and gas

    USGS Publications Warehouse

    Drew, L.J.; Attanasi, E.D.; Schuenemeyer, J.H.

    1988-01-01

    If observed oil and gas field size distributions are obtained by random samplings, the fitted distributions should approximate that of the parent population of oil and gas fields. However, empirical evidence strongly suggests that larger fields tend to be discovered earlier in the discovery process than they would be by random sampling. Economic factors also can limit the number of small fields that are developed and reported. This paper examines observed size distributions in state and federal waters of offshore Texas. Results of the analysis demonstrate how the shape of the observable size distributions change with significant hydrocarbon price changes. Comparison of state and federal observed size distributions in the offshore area shows how production cost differences also affect the shape of the observed size distribution. Methods for modifying the discovery rate estimation procedures when economic factors significantly affect the discovery sequence are presented. A primary conclusion of the analysis is that, because hydrocarbon price changes can significantly affect the observed discovery size distribution, one should not be confident about inferring the form and specific parameters of the parent field size distribution from the observed distributions. ?? 1988 International Association for Mathematical Geology.

  13. Observed oil and gas field size distributions: a consequence of the discovery process and prices of oil and gas

    SciTech Connect

    Drew, L.J.; Attanasi, E.D.; Schuenemeyer, J.H.

    1988-11-01

    If observed oil and gas field size distributions are obtained by random samplings, the fitted distributions should approximate that of the parent population of oil and gas fields. However, empirical evidence strongly suggests that larger fields tend to be discovered earlier in the discovery process than they would be by random sampling. Economic factors also can limit the number of small fields that are developed and reported. This paper examines observed size distributions in state and federal waters of offshore Texas. Results of the analysis demonstrate how the shape of the observable size distributions change with significant hydrocarbon price changes. Comparison of state and federal observed size distributions in the offshore area shows how production cost differences also affect the shape of the observed size distribution. Methods for modifying the discovery rate estimation procedures when economic factors significantly affect the discovery sequence are presented. A primary conclusion of the analysis is that, because hydrocarbon price changes can significantly affect the observed discovery size distribution, one should not be confident about inferring the form and specific parameters of the parent field size distribution from the observed distributions.

  14. Just fracking: a distributive environmental justice analysis of unconventional gas development in Pennsylvania, USA

    NASA Astrophysics Data System (ADS)

    Clough, Emily; Bell, Derek

    2016-02-01

    This letter presents a distributive environmental justice analysis of unconventional gas development in the area of Pennsylvania lying over the Marcellus Shale, the largest shale gas formation in play in the United States. The extraction of shale gas using unconventional wells, which are hydraulically fractured (fracking), has increased dramatically since 2005. As the number of wells has grown, so have concerns about the potential public health effects on nearby communities. These concerns make shale gas development an environmental justice issue. This letter examines whether the hazards associated with proximity to wells and the economic benefits of shale gas production are fairly distributed. We distinguish two types of distributive environmental justice: traditional and benefit sharing. We ask the traditional question: are there a disproportionate number of minority or low-income residents in areas near to unconventional wells in Pennsylvania? However, we extend this analysis in two ways: we examine income distribution and level of education; and we compare before and after shale gas development. This contributes to discussions of benefit sharing by showing how the income distribution of the population has changed. We use a binary dasymetric technique to remap the data from the 2000 US Census and the 2009-2013 American Communities Survey and combine that data with a buffer containment analysis of unconventional wells to compare the characteristics of the population living nearer to unconventional wells with those further away before and after shale gas development. Our analysis indicates that there is no evidence of traditional distributive environmental injustice: there is not a disproportionate number of minority or low-income residents in areas near to unconventional wells. However, our analysis is consistent with the claim that there is benefit sharing distributive environmental injustice: the income distribution of the population nearer to shale gas wells

  15. Local ISM 3D Distribution and Soft X-ray Background Inferences for Nearby Hot Gas

    NASA Technical Reports Server (NTRS)

    Puspitarini, L.; Lallement, R.; Snowden, Steven L.; Vergely, J.-L.; Snowden, S.

    2014-01-01

    Three-dimensional (3D) interstellar medium (ISM) maps can be used to locate not only interstellar (IS) clouds, but also IS bubbles between the clouds that are blown by stellar winds and supernovae, and are filled by hot gas. To demonstrate this, and to derive a clearer picture of the local ISM, we compare our recent 3D IS dust distribution maps to the ROSAT diffuse Xray background maps after removal of heliospheric emission. In the Galactic plane, there is a good correspondence between the locations and extents of the mapped nearby cavities and the soft (0.25 keV) background emission distribution, showing that most of these nearby cavities contribute to this soft X-ray emission. Assuming a constant dust to gas ratio and homogeneous 106 K hot gas filling the cavities, we modeled in a simple way the 0.25 keV surface brightness along the Galactic plane as seen from the Sun, taking into account the absorption by the mapped clouds. The data-model comparison favors the existence of hot gas in the solar neighborhood, the so-called Local Bubble (LB). The inferred mean pressure in the local cavities is found to be approx.9,400/cu cm K, in agreement with previous studies, providing a validation test for the method. On the other hand, the model overestimates the emission from the huge cavities located in the third quadrant. Using CaII absorption data, we show that the dust to CaII ratio is very small in those regions, implying the presence of a large quantity of lower temperature (non-X-ray emitting) ionized gas and as a consequence a reduction of the volume filled by hot gas, explaining at least part of the discrepancy. In the meridian plane, the two main brightness enhancements coincide well with the LB's most elongated parts and chimneys connecting the LB to the halo, but no particular nearby cavity is found towards the enhancement in the direction of the bright North Polar Spur (NPS) at high latitude. We searched in the 3D maps for the source regions of the higher energy

  16. Comparison of temperature distributions inside a PEM fuel cell with parallel and interdigitated gas distributors

    NASA Astrophysics Data System (ADS)

    Hwang, J. J.; Liu, S. J.

    A comparison of the temperature distributions in a proton exchange membrane (PEM) fuel cell between the parallel-flow gas distributors and the interdigitated gas distributor has been discussed in detail. An electrochemical-thermal coupled numerical model in a five-layer membrane-electrode assembly (MEA) is developed. The temperatures for the reactant fuels as well as the carbon fibers in the porous electrode are predicted by using a CFD technique. The overpotential across the MEA is varied to examine its effect on the temperature distributions of the PEM fuel cell. It is found that both the fuel temperature and the carbon fiber temperature are increased with increasing the total overpotential. In addition, the fuel and carbon-fiber temperature distributions are significantly affected by the flow pattern that cast on the gas distributor. Replacing the parallel-flow gas distributor by the interdigitated gas distributor will increase the local maximum temperature inside the PEM fuel cell.

  17. Painting a Picture of Gas Hydrate Distribution with Thermal Images

    SciTech Connect

    Weinberger, Jill L.; Brown, Kevin M.; Long, Philip E.

    2005-02-25

    Large uncertainties about the energy resource potential and role in global climate change of gas hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, the entire gas hydrate stability zone was sampled in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of gas hydrate in this structural system. We conclude that high gas hydrate content (30-40% of pore space of 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs.

  18. Non-Intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Delgado, Jesus; Phillips, Straun; Rubtsov, Vladimir; Chullen, Cinda

    2015-01-01

    Chemical sensors for monitoring gas composition, including oxygen, humidity, carbon dioxide, and trace contaminants, are needed to characterize and validate spacesuit design and operating parameters. This paper reports on the first prototypes of a non-intrusive gas sensing technology based on flexible sensitive patches positioned inside spacesuit prototypes and interrogated via optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. The sensitive patches are based on luminescent materials whose emission parameters vary with the partial pressure of a specific gas. Patches sensitive to carbon dioxide, humidity, and temperature have been developed, and their preliminary laboratory characterization in Mark III-like helmet parts is described. The first prototype system consists of a four-channel fiber optic luminescent detector that can be used to monitor any of the selected target gases at four locations. To switch from one gas to another we replace the (disposable) sensor patches and adjust the system settings. Repeatability among sensitive patches and of sensor performance from location to location has been confirmed, assuring that suit engineers will have flexibility in selecting multiple sensing points, fitting the sensor elements into the spacesuit, and easily repositioning the sensor elements as desired. The evaluation of the first prototype for monitoring carbon dioxide during washout studies in a spacesuit prototype is presented.

  19. Non-Intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

    NASA Technical Reports Server (NTRS)

    Delgado, Jesus; Phillips, Straun; Rubtsov, Vladimir; Chullen, Cinda

    2015-01-01

    Chemical sensors for monitoring gas composition, including oxygen, humidity, carbon dioxide, and trace contaminants are needed to characterize and validate spacesuit design and operating parameters. This paper reports on the first prototypes of a non-intrusive gas sensing technology based on flexible sensitive patches positioned inside spacesuit prototypes and interrogated by optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. The sensitive patches are based on luminescent materials whose emission parameters vary with the partial pressure of a specific gas. Patches sensitive to carbon dioxide, humidity, oxygen, and ammonia have been developed, and their preliminary characterization in the laboratory using Mark III-like helmet parts is described. The first prototype system consists of a four-channel fiber optic luminescent detector that can be used to monitor any of the selected target gases at four locations. To switch from one gas to another we replace the (disposable) sensor patches and adjust the system settings. Repeatability among sensitive patches and of sensor performance from location to location has been confirmed, assuring that suit engineers will have flexibility in selecting multiple sensing points, fitting the sensor elements into the spacesuit, and easily repositioning the sensor elements as desired. The evaluation of the first prototype for monitoring carbon dioxide during washout studies in a space suit prototype is presented.

  20. Continuous distributions of specific ventilation recovered from inert gas washout

    NASA Technical Reports Server (NTRS)

    Lewis, S. M.; Evans, J. W.; Jalowayski, A. A.

    1978-01-01

    A new technique is described for recovering continuous distributions of ventilation as a function of tidal ventilation/volume ratio from the nitrogen washout. The analysis yields a continuous distribution of ventilation as a function of tidal ventilation/volume ratio represented as fractional ventilations of 50 compartments plus dead space. The procedure was verified by recovering known distributions from data to which noise had been added. Using an apparatus to control the subject's tidal volume and FRC, mixed expired N2 data gave the following results: (a) the distributions of young, normal subjects were narrow and unimodal; (b) those of subjects over age 40 were broader with more poorly ventilated units; (c) patients with pulmonary disease of all descriptions showed enlarged dead space; (d) patients with cystic fibrosis showed multimodal distributions with the bulk of the ventilation going to overventilated units; and (e) patients with obstructive lung disease fell into several classes, three of which are illustrated.

  1. Comparing two micrometeorological techniques for estimating trace gas emissions from distributed sources

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Measuring trace gas emission from distributed sources such as treatment lagoons, treatment wetlands, land spread of manure, and feedlots requires micrometeorological methods. In this study, we tested the accuracy of two relatively new micrometeorological techniques, vertical radial plume mapping (VR...

  2. 77 FR 34123 - Pipeline Safety: Public Meeting on Integrity Management of Gas Distribution Pipelines

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-08

    ... Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Public Meeting on Integrity Management of Gas Distribution Pipelines AGENCY: Office of Pipeline Safety, Pipeline and Hazardous Materials Safety Administration, DOT. ACTION: Notice; public meeting. SUMMARY: The Pipeline and Hazardous...

  3. Measurements of gas hydrate formation probability distributions on a quasi-free water droplet.

    PubMed

    Maeda, Nobuo

    2014-06-01

    A High Pressure Automated Lag Time Apparatus (HP-ALTA) can measure gas hydrate formation probability distributions from water in a glass sample cell. In an HP-ALTA gas hydrate formation originates near the edges of the sample cell and gas hydrate films subsequently grow across the water-guest gas interface. It would ideally be desirable to be able to measure gas hydrate formation probability distributions of a single water droplet or mist that is freely levitating in a guest gas, but this is technically challenging. The next best option is to let a water droplet sit on top of a denser, immiscible, inert, and wall-wetting hydrophobic liquid to avoid contact of a water droplet with the solid walls. Here we report the development of a second generation HP-ALTA which can measure gas hydrate formation probability distributions of a water droplet which sits on a perfluorocarbon oil in a container that is coated with 1H,1H,2H,2H-Perfluorodecyltriethoxysilane. It was found that the gas hydrate formation probability distributions of such a quasi-free water droplet were significantly lower than those of water in a glass sample cell.

  4. Impact of Higher Natural Gas Prices on Local Distribution Companies and Residential Customers

    EIA Publications

    2007-01-01

    This report examines some of the problems faced by natural gas consumers as a result of increasing heating bills in recent years and problems associated with larger amounts of uncollectible revenue and lower throughput for the local distribution companies (LDCs) supplying the natural gas.

  5. Nitrogen dioxide reactions with 46 atomic main-group and transition metal cations in the gas phase: room temperature kinetics and periodicities in reactivity.

    PubMed

    Jarvis, Michael J Y; Blagojevic, Voislav; Koyanagi, Gregory K; Bohme, Diethard K

    2013-02-14

    Experimental results are reported for the gas-phase room-temperature kinetics of chemical reactions between nitrogen dioxide (NO(2)) and 46 atomic main-group and transition metal cations (M(+)). Measurements were taken with an inductively-coupled plasma/selected-ion flow tube (ICP/SIFT) tandem mass spectrometer in helium buffer gas at a pressure of 0.35 ± 0.01 Torr and at 295 ± 2 K. The atomic cations were produced at ca. 5500 K in an ICP source and allowed to decay radiatively and to thermalize to room temperature by collisions with Ar and He atoms prior to reaction with NO(2). Measured apparent bimolecular rate coefficients and primary reaction product distributions are reported for all 46 atomic metal cations and these provide an overview of trends across and down the periodic table. Three main types of reactions were observed: O-atom transfer to form either MO(+) or NO(+), electron transfer to form NO(2)(+), and addition to form MNO(2)(+). Bimolecular O-atom transfer was observed to predominate. Correlations are presented between reaction efficiency and the O-atom affinity of the metal cation and between the prevalence of NO(+) product formation and the electron recombination energy of the product metal oxide cation. Some second-order reactions are evident with metal cations that react inefficiently. Most interesting of these is the formation of the MNO(+) cation with Rh(+) and Pd(+). The higher-order chemistry with NO(2) is very diverse and includes the formation of numerous NO(2) ion clusters and a number of tri- and tetraoxide metal cations. Group 2 metal dioxide cations (CaO(2)(+), SrO(2)(+), BaO(2)(+)) exhibit a unique reaction with NO(2) to form MO(NO)(+) ions perhaps by NO transfer from NO(2) concurrent with O(2) formation by recombination of a NO(2) and an oxide oxygen.

  6. Edge seal for a porous gas distribution plate of a fuel cell

    DOEpatents

    Feigenbaum, Haim; Pudick, Sheldon; Singh, Rajindar

    1984-01-01

    In an improved seal for a gas distribution plate of a fuel cell, a groove is provided extending along an edge of the plate. A member of resinous material is arranged within the groove and a paste comprising an immobilized acid is arranged surrounding the member and substantially filling the groove. The seal, which is impervious to the gas being distributed, is resistant to deterioration by the electrolyte of the cell.

  7. Sedimentary style and oil-gas field distribution in Western Bohai Bay

    SciTech Connect

    Hansheng Qiao )

    1994-07-01

    Western Bohai Bay is located near Tianjing City and the Yanshan Mountains. Tectonically, it is part of the Bohai Bay rift, including the Qiku, Nanpu, and Cangdong depressions. The Paleogene strata consist of three cycles in the rift. Usually, the sublacustrine fans or basalts formed at the initial stage of every cycle. The dark shales and turbidites developed at the high level of lacustrine transgression. However, the deltas or evaporates appeared at the regressive stage. The sublacustrine fans or deltas generally distribute in the marginal part of a depression, with humic type kerogen. The dark shales of deep lacustrine facies in the inner part of it contain sapropel type kerogen. The transitional zone between them is interbedded shales and sandstones, with mixed type kerogen. The oil-gas fields mainly occur in the transitional zone around the oil-generating center. The great oil-gas fields are formed in areas where the big drape anticline coincided with the sublacustrine fan-front or delta-front sandstones and were sealed by shales or evaporates. A great number of small overpressured oil reservoirs are in the mature source rocks in the depression center.

  8. Gas and particle size distributions of polychlorinated naphthalenes in the atmosphere of Beijing, China.

    PubMed

    Zhu, Qingqing; Zhang, Xian; Dong, Shujun; Gao, Lirong; Liu, Guorui; Zheng, Minghui

    2016-05-01

    Polychlorinated naphthalenes (PCNs) were listed as persistent organic pollutants in the Stockholm Convention in 2015. Despite numerous studies on PCNs, little is known about their occurrence in atmospheric particulate matter of different sizes. In this study, 49 PCN congeners were investigated for their concentrations and size-specific distributions in an urban atmosphere, and preliminary exposure assessments were conducted. Ambient air samples were collected using a high-volume cascade impactor for division into a gas fraction and four particle size fractions. Samples were collected from October 2013 to June 2014 at an urban site in Beijing, China. The concentration range for PCNs in the atmosphere (gas + particle fractions) was 6.77-25.90 pg/m(3) (average 16.28 pg/m(3)). The particle-bound concentration range was 0.17-2.78 pg/m(3) (average 1.73 pg/m(3)). Therefore, PCNs were mainly found in the gas phase. The concentrations of PCNs in a fraction increased as the particle size decreased (dae > 10 μm, 10 μm ≥ dae > 2.5 μm, 2.5 μm ≥ dae > 1.0 μm and dae ≤ 1.0 μm). Consequently, PCNs were ubiquitous in inhalable fine particles, and the ΣPCNs associated with PM1.0 and PM2.5 reached 68.4% and 84.3%, respectively. Tetra-CNs and penta-CNs (the lower chlorinated homologues) predominated in the atmosphere. The homologue profiles in different size particles were almost similar, but the particulate profiles were different from those in the gas phase. Among the individual PCNs identified, CN38/40, CN52/60 and CN75 were the dominant compounds in the atmosphere. CN66/67 and CN73 collectively accounted for most of the total dioxin-like TEQ concentrations of the PCNs. Exposure to toxic compounds, such as PCNs present in PM1.0 or PM2.5, may affect human health. This work presents the first data on size-specific distributions of PCNs in the atmosphere.

  9. Spatial distribution of interstellar dust in the Sun's vicinity. Comparison with neutral sodium-bearing gas

    NASA Astrophysics Data System (ADS)

    Vergely, J.-L.; Valette, B.; Lallement, R.; Raimond, S.

    2010-07-01

    Aims: 3D tomography of the interstellar dust and gas may be useful in many respects, from the physical and chemical evolution of the interstellar medium itself to foreground decontamination of the cosmic microwave background, or various studies of the environments of specific objects. However, while spectral data cubes of the galactic emission become increasingly precise, the information on the distance to the emitting regions has not progressed as well and relies essentially on the galactic rotation curve. Our goal here is to bring more precise information on the distance to nearby interstellar dust and gas clouds within 250 pc. Methods: We apply the best available calibration methods to a carefully screened set of stellar Strömgren photometry data for targets possessing a Hipparcos parallax and spectral type classification. We combine the derived interstellar extinctions and the parallax distances for about 6000 stars to build a 3D tomography of the local dust. We use an inversion method based on a regularized Bayesian approach and a least squares criterion, optimized for this specific data set. We apply the same inversion technique to a totally independent set of neutral sodium absorption data available for about 1700 target stars. Results: We obtain 3D maps of the opacity and the distance to the main dust-bearing clouds within 250 pc and identify in those maps well-known dark clouds and high galactic more diffuse entities. We calculate the integrated extinction between the Sun and the cube boundary and compare this with the total galactic extinction derived from infrared 2D maps. The two quantities reach similar values at high latitudes, as expected if the local dust content is satisfyingly reproduced and the dust is closer than 250 pc. Those maps show a larger high latitude dust opacity in the North compared to the South, reinforcing earlier evidences. Interestingly the gas maps do not show the same asymmetry, suggesting a polar asymmetry of the dust to gas

  10. The Radial Distributions of the Two Main-sequence Components in the Young Massive Star Cluster NGC 1856

    NASA Astrophysics Data System (ADS)

    Li, Chengyuan; de Grijs, Richard; Deng, Licai; Milone, Antonino P.

    2017-01-01

    The recent discovery of double main sequences in the young, massive star cluster NGC 1856 has caught significant attention. The observations can be explained by invoking two stellar generations with different ages and metallicities or by a single generation of stars composed of two populations characterized by different rotation rates. We analyzed the number ratios of stars belonging to both main-sequence components in NGC 1856 as a function of radius. We found that their number ratios remain approximately unchanged from the cluster’s central region to its periphery, indicating that both components are homogeneously distributed in space. Through a comparison of the loci of the best-fitting isochrones with the ridge lines of both stellar components, we found that both multiple stellar populations and rapid stellar rotation can potentially explain the observed main-sequence bifurcation in NGC 1856. However, if NGC 1856 were a young representative of the old globular clusters, then the multiple stellar populations model would not be able to explain the observed homogeneity in the spatial distributions of these two components, since all relevant scenarios would predict that the second stellar generation should be formed in a more compact configuration than that of the first stellar generation, while NGC 1856 is too young for both stellar generations to have been fully mixed dynamically. We speculate that the rapid stellar rotation scenario would be the favored explanation of the observed multiple stellar sequences in NGC 1856.

  11. Importance of Pore Size Distribution of Fine-grained Sediments on Gas Hydrate Equilibrium

    NASA Astrophysics Data System (ADS)

    Kwon, T. H.; Kim, H. S.; Cho, G. C.; Park, T. H.

    2015-12-01

    Gas hydrates have been considered as a new source of natural gases. For the gas hydrate production, the gas hydrate reservoir should be depressurized below the equilibrium pressure of gas hydrates. Therefore, it is important to predict the equilibrium of gas hydrates in the reservoir conditions because it can be affected by the pore size of the host sediments due to the capillary effect. In this study, gas hydrates were synthesized in fine-grained sediment samples including a pure silt sample and a natural clayey silt sample cored from a hydrate occurrence region in Ulleung Basin, East Sea, offshore Korea. Pore size distributions of the samples were obtained by the nitrogen adsorption and desorption test and the mercury intrusion porosimetry. The equilibrium curve of gas hydrates in the fine-grained sediments were found to be significantly influenced by the clay fraction and the corresponding small pores (>50 nm in diameter). For the clayey silt sample, the equilibrium pressure was higher by ~1.4 MPa than the bulk equilibrium pressure. In most cases of oceanic gas hydrate reservoirs, sandy layers are found interbedded with fine-grained sediment layers while gas hydrates are intensively accumulated in the sandy layers. Our experiment results reveal the inhibition effect of fine-grained sediments against gas hydrate formation, in which greater driving forces (e.g., higher pressure or lower temperature) are required during natural gas migration. Therefore, gas hydrate distribution in interbedded layers of sandy and fine-grained sediments can be explained by such capillary effect induced by the pore size distribution of host sediments.

  12. Particle size distribution and gas-particle partitioning of polychlorinated biphenyls in the atmosphere in Beijing, China.

    PubMed

    Zhu, Qingqing; Zheng, Minghui; Liu, Guorui; Zhang, Xian; Dong, Shujun; Gao, Lirong; Liang, Yong

    2017-01-01

    Size-fractionated samples of urban particulate matter (PM; ≤1.0, 1.0-2.5, 2.5-10, and >10 μm) and gaseous samples were simultaneously obtained to study the distribution of polychlorinated biphenyls (PCBs) in the atmosphere in Beijing, China. Most recent investigations focused on the analysis of gaseous PCBs, and much less attention has been paid to the occurrence of PCBs among different PM fractions. In the present study, the gas-particle partitioning and size-specific distribution of PCBs in atmosphere were investigated. The total concentrations (gas + particle phase fractions) of Σ12 dioxin-like PCBs, Σ7 indicator PCBs, and ΣPCBs were 1.68, 42.1, and 345 pg/m(3), respectively. PCBs were predominantly in the gas phase (86.8-99.0 % of the total concentrations). The gas-particle partition coefficients (K p ) of PCBs were found to be a significant linear correlated with the subcooled liquid vapor pressures (P L(0)) (R (2) = 0.83, P < 0.01). The slope (m r ) implied that the gas-particle partitioning of PCBs was affected both by the mechanisms of adsorption and absorption. In addition, the concentrations of PCBs increased as the particle size decreased (>10, 2.5-10, 1.0-2.5, and ≤1.0 μm), with most of the PCBs contained in the fraction of ≤1.0 μm (53.4 % of the total particulate concentrations). Tetra-CBs were the main homolog in the air samples in the gas phase and PM fractions, followed by tri-CBs. This work will contribute to the knowledge of PCBs among different PM fractions and fill the gap of the size distribution of particle-bound dioxin-like PCBs in the air.

  13. Distribution of the Habitat Suitability of the Main Malaria Vector in French Guiana Using Maximum Entropy Modeling.

    PubMed

    Moua, Yi; Roux, Emmanuel; Girod, Romain; Dusfour, Isabelle; de Thoisy, Benoit; Seyler, Frédérique; Briolant, Sébastien

    2016-12-22

    Malaria is an important health issue in French Guiana. Its principal mosquito vector in this region is Anopheles darlingi Root. Knowledge of the spatial distribution of this species is still very incomplete due to the extent of French Guiana and the difficulty to access most of the territory. Species distribution modeling based on the maximal entropy procedure was used to predict the spatial distribution of An. darlingi using 39 presence sites. The resulting model provided significantly high prediction performances (mean 10-fold cross-validated partial area under the curve and continuous Boyce index equal to, respectively, 1.11-with a level of omission error of 20%-and 0.42). The model also provided a habitat suitability map and environmental response curves in accordance with the known entomological situation. Several environmental characteristics that had a positive correlation with the presence of An. darlingi were highlighted: nonpermanent anthropogenic changes of the natural environment, the presence of roads and tracks, and opening of the forest. Some geomorphological landforms and high altitude landscapes appear to be unsuitable for An. darlingi The species distribution modeling was able to reliably predict the distribution of suitable habitats for An. darlingi in French Guiana. Results allowed completion of the knowledge of the spatial distribution of the principal malaria vector in this Amazonian region, and identification of the main factors that favor its presence. They should contribute to the definition of a necessary targeted vector control strategy in a malaria pre-elimination stage, and allow extrapolation of the acquired knowledge to other Amazonian or malaria-endemic contexts.

  14. Effects of YORP-induced rotational fission on the small size end of the Main Belt asteroid size distribution

    NASA Astrophysics Data System (ADS)

    Rossi, Alessandro; Jacobson, S.; Marzari, F.; Scheeres, D.; Davis, D. R.

    2013-10-01

    From the results of a comprehensive asteroid population evolution model, we conclude that the YORP-induced rotational fission hypothesis has strong repercussions for the small size end of the Main Belt asteroid size frequency distribution. These results are consistent with observed asteroid population statistics. The foundation of this model is the asteroid rotation model of Marzari et al. (2011), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur). The YORP effect timescale for large asteroids with diameters D > ~6 km is longer than the collision timescale in the Main Belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D < ~6 km, the asteroid population evolution model confirms that YORP-induced rotational fission destroys small asteroids more frequently than collisions. Therefore, the frequency of these small asteroids is determined by an equilibrium between the creation of new asteroids out of the impact debris of larger asteroids and the destruction of these asteroids by YORP-induced rotational fission. By introducing a new source of destruction that varies strongly with size, YORP-induced rotational fission alters the slope of the size frequency distribution. Using the outputs of the asteroid population evolution model and a 1-D collision evolution model, we can generate this new size frequency distribution and it matches the change in slope observed by the SKADS survey (Gladman 2009). This agreement is achieved with both an accretional power-law or a truncated “Asteroids were Born Big” size frequency distribution (Weidenschilling 2010, Morbidelli 2009).

  15. Airflow, gas deposition, and lesion distribution in the nasal passages.

    PubMed Central

    Morgan, K T; Monticello, T M

    1990-01-01

    The nasal passages of laboratory animals and man are complex, and lesions induced in the delicate nasal lining by inhaled air pollutants vary considerably in location and nature. The distribution of nasal lesions is generally a consequence of regional deposition of the inhaled material, local tissue susceptibility, or a combination of these factors. Nasal uptake and regional deposition are are influenced by numerous factors including the physical and chemical properties of the inhaled material, such as water solubility and reactivity; airborne concentration and length of exposure; the presence of other air contaminants such as particulate matter; nasal metabolism, and blood and mucus flow. For certain highly water-soluble or reactive gases, nasal airflow patterns play a major role in determining lesion distribution. Studies of nasal airflow in rats and monkeys, using casting and molding techniques combined with a water-dye model, indicate that nasal airflow patterns are responsible for characteristic differences in the distribution of nasal lesions induced by formaldehyde in these species. Local tissue susceptibility is also a complex issue that may be a consequence of many factors, including physiologic and metabolic characteristics of the diverse cell populations that comprise each of the major epithelial types lining the airways. Identification of the principal factors that influence the distribution and nature of nasal lesions is important when attempting the difficult process of determining potential human risks using data derived from laboratory animals. Toxicologic pathologists can contribute to this process by carefully identifying the site and nature of nasal lesions induced by inhaled materials. Images FIGURE 4. FIGURE 6. FIGURE 7. PMID:2200663

  16. Spatially and temporally resolved gas distributions around heterogeneous catalysts using infrared planar laser-induced fluorescence

    PubMed Central

    Zetterberg, Johan; Blomberg, Sara; Gustafson, Johan; Evertsson, Jonas; Zhou, Jianfeng; Adams, Emma C.; Carlsson, Per-Anders; Aldén, Marcus; Lundgren, Edvin

    2015-01-01

    Visualizing and measuring the gas distribution in close proximity to a working catalyst is crucial for understanding how the catalytic activity depends on the structure of the catalyst. However, existing methods are not able to fully determine the gas distribution during a catalytic process. Here we report on how the distribution of a gas during a catalytic reaction can be imaged in situ with high spatial (400 μm) and temporal (15 μs) resolution using infrared planar laser-induced fluorescence. The technique is demonstrated by monitoring, in real-time, the distribution of carbon dioxide during catalytic oxidation of carbon monoxide above powder catalysts. Furthermore, we demonstrate the versatility and potential of the technique in catalysis research by providing a proof-of-principle demonstration of how the activity of several catalysts can be measured simultaneously, either in the same reactor chamber, or in parallel, in different reactor tubes. PMID:25953006

  17. Spatial distribution of venous gas emboli in the lungs

    NASA Technical Reports Server (NTRS)

    Souders, J. E.; Doshier, J. B.; Polissar, N. L.; Hlastala, M. P.

    1999-01-01

    The distribution of gaseous pulmonary emboli is presumed to be determined by their buoyancy. We hypothesized that regional pulmonary blood flow may also influence their distribution. Therefore, pulmonary blood flow was measured in supine, anesthetized dogs with use of 15-microm fluorescent microspheres at baseline and during N(2) embolism. The animals were killed, and the lungs were excised, air-dried, and diced into approximately 2-cm(3) pieces with weights and spatial coordinates recorded. Embolism was defined as a >10% flow decrease relative to baseline. Vertically, the incidence of embolism increased substantially by 6 +/- 1% per additional centimeter in height compared with baseline (P = 0.0003). Embolism also increased radially by 3 +/- 1%/cm from the hilum (P = 0.002). There was a weaker but statistically significant increase in embolism to pieces with greater baseline flow, 9 +/- 2% for every 1. 0 increase in relative baseline flow (P = 0.008). We conclude that the distribution of gaseous emboli is influenced by buoyancy and flow dynamics within the pulmonary vasculature.

  18. Natural Gas Transmission and Distribution Model of the National Energy Modeling System. Volume 1

    SciTech Connect

    1998-01-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. The NGTDM is the model within the NEMS that represents the transmission, distribution, and pricing of natural gas. The model also includes representations of the end-use demand for natural gas, the production of domestic natural gas, and the availability of natural gas traded on the international market based on information received from other NEMS models. The NGTDM determines the flow of natural gas in an aggregate, domestic pipeline network, connecting domestic and foreign supply regions with 12 demand regions. The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. Subsequent chapters of this report provide: an overview of NGTDM; a description of the interface between the NEMS and NGTDM; an overview of the solution methodology of the NGTDM; the solution methodology for the Annual Flow Module; the solution methodology for the Distributor Tariff Module; the solution methodology for the Capacity Expansion Module; the solution methodology for the Pipeline Tariff Module; and a description of model assumptions, inputs, and outputs.

  19. Qualitative gas temperature distribution in positive DC glow corona using spectral image processing in atmospheric air

    NASA Astrophysics Data System (ADS)

    Matsumoto, Takao; Inada, Yoichi; Shimizu, Daisuke; Izawa, Yasuji; Nishijima, Kiyoto

    2015-01-01

    An experimental method of determining a qualitative two-dimensional image of the gas temperature in stationary atmospheric nonthermal plasma by spectral image processing was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. The changes in the gas temperature distribution due to the amplitude of applied voltage and the ambient gas pressure were investigated. Spectral images of a positive DC glow corona were taken using a gated ICCD camera with ultranarrow band-pass filters, corresponding to the head and tail of a N2 second positive system band (0-2). The qualitative gas temperature was obtained from the emission intensity ratio between the head and tail of the N2 second positive system band (0-2). From the results, we confirmed that the gas temperature and its distribution of a positive DC glow corona increased with increasing applied voltage. In particular, just before the sparkover voltage, a distinctly high temperature region was formed in the positive DC glow at the tip of the rod electrode. In addition, the gas temperature decreased and its distribution spread diffusely with decreasing ambient gas pressure.

  20. CO-dark gas and molecular filaments in Milky Way-type galaxies - II. The temperature distribution of the gas

    NASA Astrophysics Data System (ADS)

    Glover, Simon C. O.; Smith, Rowan J.

    2016-11-01

    We investigate the temperature distribution of CO-dark molecular hydrogen (H2) in a series of disc galaxies simulated using the AREPO moving-mesh code. In conditions similar to those in the Milky Way, we find that H2 has a flat temperature distribution ranging from 10 to 100 K. At T < 30 K, the gas is almost fully molecular and has a high CO content, whereas at T > 30 K, the H2 fraction spans a broader range and the CO content is small, allowing us to classify gas in these two regimes as CO-bright and CO-dark, respectively. The mean sound speed in the CO-dark H2 is cs, dark = 0.64 km s-1, significantly lower than the value in the cold atomic gas (cs, CNM = 1.15 km s-1), implying that the CO-dark molecular phase is more susceptible to turbulent compression and gravitational collapse than its atomic counterpart. We further show that the temperature of the CO-dark H2 is highly sensitive to the strength of the interstellar radiation field, but that conditions in the CO-bright H2 remain largely unchanged. Finally, we examine the usefulness of the [C II] and [O I] fine-structure lines as tracers of the CO-dark gas. We show that in Milky Way-like conditions, diffuse [C II] emission from this gas should be detectable. However, it is a problematic tracer of this gas, as there is only a weak correlation between the brightness of the emission and the H2 surface density. The situation is even worse for the [O I] line, which shows no correlation with the H2 surface density.

  1. Occurrence and distribution of gas vesicle genes among cyanobacteria.

    PubMed Central

    Damerval, T; Castets, A M; Guglielmi, G; Houmard, J; Tandeau de Marsac, N

    1989-01-01

    Gas vesicles (GV) are specialized cell inclusions providing many aquatic procaryotes with buoyancy. In the cyanobacterium Calothrix sp. strain PCC 7601, at least four genes are involved in GV formation. One of those, gvpA1, encodes the major structural GV protein (70 amino acids) and belongs to a multigene family (gvpA1, gvpA2, gvpD). The fourth gene, gvpC, encodes a 162-amino-acid protein, the function of which is still unclear. We used the Calothrix gvpA1 and gvpC genes as probes to perform Southern hybridization experiments with DNA extracted from various cyanobacterial strains. The gvpA gene was found in all the strains that synthesize GV, indicating that its product is an obligatory component of GV. Furthermore, it was found to occur as multiple copies in most of the strains tested. The gvpC gene was only detected in some strains able to synthesize a large amount of GV within a short period. This suggests that the gvpC gene product is a dispensable protein for GV formation and is involved in the efficiency of the assembly process. Based on the occurrence of the gvp genes and on DNA-DNA hybridization patterns, genus assignments are discussed. Images PMID:2493445

  2. A Lagrangian View of Stratospheric Trace Gas Distributions

    NASA Technical Reports Server (NTRS)

    Schoeberl, M. R.; Sparling, L.; Dessler, A.; Jackman, C. H.; Fleming, E. L.

    1998-01-01

    As a result of photochemistry, some relationship between the stratospheric age-of-air and the amount of tracer contained within an air sample is expected. The existence of such a relationship allows inferences about transport history to be made from observations of chemical tracers. This paper lays down the conceptual foundations for the relationship between age and tracer amount, developed within a Lagrangian framework. In general, the photochemical loss depends not only on the age of the parcel but also on its path. We show that under the "average path approximation" that the path variations are less important than parcel age. The average path approximation then allows us to develop a formal relationship between the age spectrum and the tracer spectrum. Using the relation between the tracer and age spectra, tracer-tracer correlations can be interpreted as resulting from mixing which connects parts of the single path photochemistry curve, which is formed purely from the action of photochemistry on an irreducible parcel. This geometric interpretation of mixing gives rise to constraints on trace gas correlations, and explains why some observations are do not fall on rapid mixing curves. This effect is seen in the ATMOS observations.

  3. Expression and distribution of aggrecanases in human larynx: ADAMTS-5/aggrecanase-2 is the main aggrecanase in laryngeal carcinoma.

    PubMed

    Filou, S; Stylianou, M; Triantaphyllidou, I E; Papadas, T; Mastronikolis, N S; Goumas, P D; Papachristou, D J; Ravazoula, P; Skandalis, S S; Vynios, D H

    2013-04-01

    Members of the ADAMTS family of proteases degrade proteoglycans and thereby have the potential to alter tissue architecture and regulate cellular functions. Aggrecanases are the main enzymes responsible for aggrecan degradation, due to their specific cleavage pattern. In this study, the expression status, the macromolecular organization and localization of ADAMTS-1, ADAMTS-4/aggrecanase-1 and ADAMTS-5/aggrecanase-2 in human normal larynx and laryngeal squamous cell carcinoma (LSCC) were investigated. On mRNA level, the results showed that ADAMTS-4 was the highest expressed enzyme in normal larynx, whereas ADAMTS-5 was the main aggrecanase in LSCC presenting a stage-related increase up to stage III (8-fold higher expression compared to normal), and thereafter decreased in stage IV. Accordingly, immunohistochemical analysis showed that ADAMTS-5, but not ADAMTS-4, was highly expressed by carcinoma cells. Sequential extraction revealed an altered distribution and organization of multiple molecular forms (latent, activated and fragmented forms) of the enzymes within the cancerous and their corresponding macroscopically normal laryngeal tissues, compared to the normal ones. Importantly, these analyses indicated that critical macromolecular changes occurred from the earliest LSCC stages not only in malignant parts of the tissue but also in areas that were not in proximity to carcinoma cells and appeared otherwise normal. Overall, the results of the present study show that ADAMTS-5/aggrecanase-2 is the main aggrecanase present in laryngeal carcinoma suggesting a critical role for the enzyme in aggrecan degradation and laryngeal tissue destruction during tumor progression.

  4. STAR FORMATION AND DISTRIBUTIONS OF GAS AND DUST IN THE CIRCINUS CLOUD

    SciTech Connect

    Shimoikura, Tomomi; Dobashi, Kazuhito

    2011-04-10

    We present results of a study on the Circinus cloud based on {sup 13}CO (J = 1 - 0) data as well as visual to near-infrared (JHK{sub S}) extinction maps, to investigate the distributions of gas and dust around the cloud. The global {sup 13}CO distribution of the Circinus cloud is revealed for the first time, and the total molecular mass of the cloud is estimated to be 2.5 x 10{sup 4} M{sub sun} for the assumed distance 700 pc. Two massive clumps in the cloud, called Circinus-W and Circinus-E, have a mass of {approx}5 x 10{sup 3} M{sub sun}. These clumps are associated with a number of young stellar objects (YSOs) searched for in the literature, indicating that they are the most active star-forming sites in Circinus. All of the extinction maps show good agreement with the {sup 13}CO distribution. We derived the average N({sup 13}CO)/A{sub V} ratio in the Circinus cloud to be 1.25 x 10{sup 15} cm{sup -2} mag{sup -1} by comparing the extinction maps with the {sup 13}CO data. The extinction maps also allowed us to probe into the reddening law over the Circinus cloud. We found that there is a clear change in dust properties in the densest regions of Circinus-W and Circinus-E, possibly due to grain growth in the dense cloud interior. Among the YSOs found in the literature, we attempted to infer the ages and masses of the H{alpha} emission-line stars forming in the two clumps, and found that they are likely to be younger than 1 Myr, having a relatively small mass of {approx}<2 M{sub sun} at the zero-age main sequence.

  5. Partition and size distribution of heavy metals in the flue gas from municipal solid waste incinerators in Taiwan.

    PubMed

    Yuan, Chung-Shin; Lin, Hsun-Yu; Wu, Chun-Hsin; Liu, Ming-Han

    2005-03-01

    This study investigates the partition of heavy metals in both solid and gas phases in the flue gas from municipal solid waste (MSW) incinerators. Six MSW incinerators in Taiwan were examined and heavy metals in the flue gas at the inlets and outlets of air pollution control devices (APCDs) were analyzed. Heavy metals including Hg, Pb, Cd, Zn, Cu and Cr were sampled by USEPA Method 29 and further analyzed using inductively coupled plasma-mass spectroscopy (ICP-MS) and cold vapor atomic absorption spectrometry (CVAAS). Experimental results revealed that the removal efficiencies of the APCDs for the heavy metals Pb, Cd, Zn, Cu and Cr greatly exceeded 90%, but that of Hg did not. Two groups of heavy metals upstream of APCDs were observed. Pb, Cd, Zn, Cu and Cr were present mainly in the solid phase with a solid to gas ratio (S/G) of over 12.3. However, in most cases, mercury appeared mainly in the gas phase with an S/G ratio from 0.15 to 1.04, because it has a low boiling point. Additionally, treatment with the APCDs increased the S/G ratio of mercury because gaseous mercury could be removed by injecting powdered activated carbon (PAC) into the flue gas. Moreover, the distribution of particle sizes in the solid phase was bimodal. Finer particles (d(p)2.5 microm) contained more Cr and Hg.

  6. Changes in the Distribution of Atlantic Bluefin Tuna (Thunnus thynnus) in the Gulf of Maine 1979-2005

    PubMed Central

    Golet, Walter J.; Galuardi, Benjamin; Cooper, Andrew B.; Lutcavage, Molly E.

    2013-01-01

    The Gulf of Maine, NW Atlantic Ocean, is a productive, seasonal foraging ground for Atlantic bluefin tuna (Thunnus thynnus), but commercial landings of adult size classes were up to 40% below the allocated total allowable catch between 2004 to 2008 for the rod and reel, harpoon, and purse seine categories in the Gulf of Maine. Reduction in Atlantic bluefin tuna catches in the Gulf of Maine could represent a decline in spawning stock biomass, but given wide-ranging, complex migration patterns, and high energetic requirements, an alternative hypothesis is that their dispersal patterns shifted to regions with higher prey abundance or profitability, reducing availability to U.S. fishing fleets. This study fit generalized linear models to Atlantic bluefin tuna landings data collected from fishermen’s logbooks (1979-2005) as well as the distances between bluefin tuna schools and Atlantic herring (Clupeaharengus), a primary prey species, to test alternative hypotheses for observed shifts in Atlantic bluefin tuna availability in the Gulf of Maine. For the bluefin model, landings varied by day of year, latitude and longitude. The effect of latitude differed by day of year and the effect of longitude differed by year. The distances between Atlantic bluefin tuna schools and Atlantic herring schools were significantly smaller (p<0.05) than would be expected from a randomly distributed population. A time series of average bluefin tuna school positions was positively correlated with the average number of herring captured per tow on Georges Bank in spring and autumn surveys respectively (p<0.01, r2=0.24, p<0.01, r2=0.42). Fishermen’s logbooks contributed novel spatial and temporal information towards testing these hypotheses for the bluefin tuna fishery. PMID:24069420

  7. Changes in the distribution of atlantic bluefin tuna (Thunnus thynnus) in the Gulf of Maine 1979-2005.

    PubMed

    Golet, Walter J; Galuardi, Benjamin; Cooper, Andrew B; Lutcavage, Molly E

    2013-01-01

    The Gulf of Maine, NW Atlantic Ocean, is a productive, seasonal foraging ground for Atlantic bluefin tuna (Thunnus thynnus), but commercial landings of adult size classes were up to 40% below the allocated total allowable catch between 2004 to 2008 for the rod and reel, harpoon, and purse seine categories in the Gulf of Maine. Reduction in Atlantic bluefin tuna catches in the Gulf of Maine could represent a decline in spawning stock biomass, but given wide-ranging, complex migration patterns, and high energetic requirements, an alternative hypothesis is that their dispersal patterns shifted to regions with higher prey abundance or profitability, reducing availability to U.S. fishing fleets. This study fit generalized linear models to Atlantic bluefin tuna landings data collected from fishermen's logbooks (1979-2005) as well as the distances between bluefin tuna schools and Atlantic herring (Clupeaharengus), a primary prey species, to test alternative hypotheses for observed shifts in Atlantic bluefin tuna availability in the Gulf of Maine. For the bluefin model, landings varied by day of year, latitude and longitude. The effect of latitude differed by day of year and the effect of longitude differed by year. The distances between Atlantic bluefin tuna schools and Atlantic herring schools were significantly smaller (p<0.05) than would be expected from a randomly distributed population. A time series of average bluefin tuna school positions was positively correlated with the average number of herring captured per tow on Georges Bank in spring and autumn surveys respectively (p<0.01, r(2)=0.24, p<0.01, r(2)=0.42). Fishermen's logbooks contributed novel spatial and temporal information towards testing these hypotheses for the bluefin tuna fishery.

  8. Evolution of bubble size distribution from gas blowout in shallow water

    NASA Astrophysics Data System (ADS)

    Zhao, Lin; Boufadel, Michel C.; Lee, Kenneth; King, Thomas; Loney, Norman; Geng, Xiaolong

    2016-03-01

    Gas is often emanated from the sea bed during a subsea oil and gas blowout. The size of a gas bubble changes due to gas dissolution in the ambient water and expansion as a result of a decrease in water pressure during the rise. It is important to understand the fate and transport of gas bubbles for the purpose of environmental and safety concerns. In this paper, we used the numerical model, VDROP-J to simulate gas formation in jet/plume upon release, and dissolution and expansion while bubble rising during a relatively shallow subsea gas blowout. The model predictions were an excellent match to the experimental data. Then a gas dissolution and expansion module was included in the VDROP-J model to predict the fate and transport of methane bubbles rising due to a blowout through a 0.10 m vertical orifice. The numerical results indicated that gas bubbles would increase the mixing energy in released jets, especially at small distances and large distances from the orifice. This means that models that predict the bubble size distribution (BSD) should account for this additional mixing energy. It was also found that only bubbles of certain sizes would reach the water surfaces; small bubbles dissolve fast in the water column, while the size of the large bubbles decreases. This resulted in a BSD that was bimodal near the orifice, and then became unimodal.

  9. Biogenic Gas Dynamics in Peat Soil Blocks using Ground Penetrating Radar: a Comparative Study in the Laboratory between Peat Soils from the Everglades and from two Northern Peatlands in Minnesota and Maine

    NASA Astrophysics Data System (ADS)

    Cabolova, Anastasija

    Peatlands cover a total area of approximately 3 million square kilometers and are one of the largest natural sources of atmospheric methane ( CH4) and carbon dioxide (CO 2). Most traditional methods used to estimate biogenic gas dynamics are invasive and provide little or no information about lateral distribution of gas. In contrast, Ground Penetrating Radar (GPR) is an emerging technique for non-invasive investigation of gas dynamics in peat soils. This thesis establishes a direct comparison between gas dynamics (i.e. build-up and release) of four different types of peat soil using GPR. Peat soil blocks were collected at peatlands with contrasting latitudes, including the Everglades, Maine and Minnesota. A unique two-antenna GPR setup was used to monitor biogenic gas buildup and ebullition events over a period of 4.5 months, constraining GPR data with surface deformation measurements and direct CH 4 and CO2 concentration measurements. The effect of atmospheric pressure was also investigated. This study has implications for better understanding global gas dynamics and carbon cycling in peat soils and its role in climate change.

  10. Minimization of Blast furnace Fuel Rate by Optimizing Burden and Gas Distribution

    SciTech Connect

    Dr. Chenn Zhou

    2012-08-15

    The goal of the research is to improve the competitive edge of steel mills by using the advanced CFD technology to optimize the gas and burden distributions inside a blast furnace for achieving the best gas utilization. A state-of-the-art 3-D CFD model has been developed for simulating the gas distribution inside a blast furnace at given burden conditions, burden distribution and blast parameters. The comprehensive 3-D CFD model has been validated by plant measurement data from an actual blast furnace. Validation of the sub-models is also achieved. The user friendly software package named Blast Furnace Shaft Simulator (BFSS) has been developed to simulate the blast furnace shaft process. The research has significant benefits to the steel industry with high productivity, low energy consumption, and improved environment.

  11. Gas swelling and deuterium distribution in beryllium implanted with deuterium ions

    SciTech Connect

    Chernikov, V.N.; Alimov, V.Kh.; Zakharov, A.P.

    1995-09-01

    An extensive TEM study of the microstructure of Be TIP-30 irradiated with 3 and 10 keV D ions up to fluences, {Phi}, in the range from 3 x 10{sup 20} to 8 x 10{sup 21} D/m{sup 2} at temperatures T{sub irr} = 300 K, 500 K and 700 K has been carried out. Depth distributions of deuterium in the form of separate D atoms and D{sub 2} molecules have been investigated by means of SIMS and RGA methods, correspondingly. D ion irradiation is accompanied by blistering and gives rise to different kind of destructions depending mainly on the irradiation temperature. Irradiation with D ions at 300 K leads to the formation of tiny highly pressurized D{sub 2} bubbles reminiscent of He bubbles in Be. Under 3 keV D ion irradiation D{sub 2} bubbles ({bar r}{sub b} {approx} 0.7 nm) appear at a fluence as low as 3x10{sup 20} D/m{sup 2}. Irradiation at 500 K results in the development, along with relatively small facetted bubbles, of larger oblate gas-filled cavities accumulating most of injected D atoms and providing for much higher gas swelling values as compared to irradiation at 300 K. The increase of D and/or T{sub irr}, to 700 K causes the further coarsening of large cavities which are transformed into sub-surface labyrinth structures. D and He ion implantation leads to the enhanced growth of porous microcrystalline layers of c.p.h.-BeO oxide with a microstructure which differs considerably from that of oxide layers on electropolished surfaces of Be. Based on the analysis of experimental data questions of deuterium reemission, thermal desorption and trapping in Be have been discussed in detail.

  12. Pore scale distribution of gas hydrates in sediments by micro X-ray Computed Tomography (X-CT)

    NASA Astrophysics Data System (ADS)

    Hu, G.; Li, C.; Ye, Y.; Liu, C.; Best, A. I.

    2013-12-01

    A dedicated apparatus was developed to observe in-situ pore scale distribution of gas hydrate directly during hydrate formation in artificial cores. The high-resolution X-ray Computed Tomography (type: GE Sensing & Inspection Technologies GmbH Phoenix x-ray V/tomex/s) was used and the effective resolution for observing gas hydrate bearing sediments can up to about 18μm. Methane gas hydrate was formed in 0.425-0.85mm sands under a pressure of 6MPa and a temperature of 3°C. During the process, CT scanning was conducted if there's a pressure drop (the scanning time is 66 minutes each time), so that the hydrate morphology could be detected. As a result, five scanning CT images of the same section during gas hydrate formation (i.e. hydrate saturation at 3.9%, 24.6%, 35.0%, 51.4% and 97.0%) were obtained. The result shows that at each hydrate saturation level, hydrate morphology models are complicated. The occurrence of 'floating model' (i.e. hydrate floats in pore fluid), 'contact model' (i.e. hydrate contact with the sediment particle), and the 'cementing model' (i.e. hydrates cement the sediment particles) can be found at the same time (Fig. 1). However, it shows that at different hydrate formation stages, the dominant hydrate morphology are not the same. For instance, at the first stage of hydrate formation, although there are some hydrates floating in the pore fluid, most hydrates connect the sediment particles. Consequently, the hydrate morphology at this moment can be described as a cementing model. With this method, it can be obtained that at the higher level of saturation (e.g., hydrate saturation at 24.6% and 35.0%), hydrates are mainly grow as a floating model. As hydrate saturation is much higher (e.g. after hydrate saturation is more than 51.4%), however, the floating hydrates coalesce with each other and the hydrates cement the sediment particle again. The direct observed hydrate morphology presented here may have significant impact on investigating

  13. Distribution of gas in the inner comae of comets

    NASA Technical Reports Server (NTRS)

    Combi, Michael

    1990-01-01

    In order to understand the physical and chemical processes which produce the observed spatial morphology of the cometary coma, it is necessary to analyze observational data with physically meaningful models. Thus, a coupled program of theoretical modeling and complementary observational data analysis was undertaken regarding the spatial distributions of neutral gases in the coma. More, specifically, the particular topics of interest are: (1) the theoretical modeling of the nonequilibrium dynamics of the inner coma with emphasis on the region of the coma from the transition from collisional fluid flow out to the free-flow region and on observable conditions in the coma (i.e., density, outflow speed, and temperature); and (2) the model analysis of an important set of long-slit CCD spectra of comets. The side-by-side development of models along with the observation and analysis of data is an important and integral part of this project. The scientific community has in hand valuable observational and in situ data regarding one comet, Halley. It is important to use Halley as the benchmark by which other remotely observed comet data can be understood. Therefore, the self-consistant analysis of data with appropriate models is of the utmost importance. The data analysis work includes the analysis of the spatial profiles of (OI), NH2, CN, and C2.

  14. Process for forming integral edge seals in porous gas distribution plates utilizing a vibratory means

    NASA Technical Reports Server (NTRS)

    Feigenbaum, Haim (Inventor); Pudick, Sheldon (Inventor)

    1988-01-01

    A process for forming an integral edge seal in a gas distribution plate for use in a fuel cell. A seal layer is formed along an edge of a porous gas distribution plate by impregnating the pores in the layer with a material adapted to provide a seal which is operative dry or when wetted by an electrolyte of a fuel cell. Vibratory energy is supplied to the sealing material during the step of impregnating the pores to provide a more uniform seal throughout the cross section of the plate.

  15. Stage 1: Expression of interest and consultation document for natural gas distribution in New Brunswick

    SciTech Connect

    1998-12-01

    The New Brunswick government intends to award a franchise to establish natural gas distribution in the province. To this end, the province wishes to invite bids from qualified entities to establish gas distribution facilities. The province will select the preferred bidder(s) through a two-stage competitive bidding process. This document details the province`s policy objectives, questions and issues to be addressed in stage 1 of the process, and the schedule for the process. Appendices include copies of relevant provincial statutes and regulations.

  16. The implementation of rare events logistic regression to predict the distribution of mesophotic hard corals across the main Hawaiian Islands

    PubMed Central

    Franklin, Erik C.; Kelley, Christopher; Frazer, L. Neil; Toonen, Robert J.

    2016-01-01

    Predictive habitat suitability models are powerful tools for cost-effective, statistically robust assessment of the environmental drivers of species distributions. The aim of this study was to develop predictive habitat suitability models for two genera of scleractinian corals (Leptoserisand Montipora) found within the mesophotic zone across the main Hawaiian Islands. The mesophotic zone (30–180 m) is challenging to reach, and therefore historically understudied, because it falls between the maximum limit of SCUBA divers and the minimum typical working depth of submersible vehicles. Here, we implement a logistic regression with rare events corrections to account for the scarcity of presence observations within the dataset. These corrections reduced the coefficient error and improved overall prediction success (73.6% and 74.3%) for both original regression models. The final models included depth, rugosity, slope, mean current velocity, and wave height as the best environmental covariates for predicting the occurrence of the two genera in the mesophotic zone. Using an objectively selected theta (“presence”) threshold, the predicted presence probability values (average of 0.051 for Leptoseris and 0.040 for Montipora) were translated to spatially-explicit habitat suitability maps of the main Hawaiian Islands at 25 m grid cell resolution. Our maps are the first of their kind to use extant presence and absence data to examine the habitat preferences of these two dominant mesophotic coral genera across Hawai‘i. PMID:27441122

  17. The implementation of rare events logistic regression to predict the distribution of mesophotic hard corals across the main Hawaiian Islands.

    PubMed

    Veazey, Lindsay M; Franklin, Erik C; Kelley, Christopher; Rooney, John; Frazer, L Neil; Toonen, Robert J

    2016-01-01

    Predictive habitat suitability models are powerful tools for cost-effective, statistically robust assessment of the environmental drivers of species distributions. The aim of this study was to develop predictive habitat suitability models for two genera of scleractinian corals (Leptoserisand Montipora) found within the mesophotic zone across the main Hawaiian Islands. The mesophotic zone (30-180 m) is challenging to reach, and therefore historically understudied, because it falls between the maximum limit of SCUBA divers and the minimum typical working depth of submersible vehicles. Here, we implement a logistic regression with rare events corrections to account for the scarcity of presence observations within the dataset. These corrections reduced the coefficient error and improved overall prediction success (73.6% and 74.3%) for both original regression models. The final models included depth, rugosity, slope, mean current velocity, and wave height as the best environmental covariates for predicting the occurrence of the two genera in the mesophotic zone. Using an objectively selected theta ("presence") threshold, the predicted presence probability values (average of 0.051 for Leptoseris and 0.040 for Montipora) were translated to spatially-explicit habitat suitability maps of the main Hawaiian Islands at 25 m grid cell resolution. Our maps are the first of their kind to use extant presence and absence data to examine the habitat preferences of these two dominant mesophotic coral genera across Hawai'i.

  18. Thermal Modeling of the Main Rings of Saturn through random distribution particle arrays and ray-tracing simulations

    NASA Astrophysics Data System (ADS)

    Flandes, Alberto; Spilker, Linda; Déau, Estelle

    2016-10-01

    Saturn's rings are a complex collection of icy particles with diameters from 1 m to few meters. Their natural window of study is the infrared because its temperatures are between 40K and 120K. The main driver of the temperature of these rings is the direct solar radiation as well as the solar radiation reflected off Saturn's atmosphere. The second most important energy source is the infrared radiation coming from Saturn itself. The study of the variations of temperatures of the rings, or, in general, their thermal behavior, may provide important information on their composition, their structure and their dynamics. Models that consider these and other energy sources are able to explain, to a first approximation, the observed temperature variations of the rings. The challenge for these models is to accurately describe the variation of illumination on the rings, i. e., how the illuminated and non-illuminated regions of the ring particles change at the different observation geometries. This shadowing mainly depends on the optical depth, as well as the general structure of the rings.In this work, We show a semi-analytical model that considers the main energy sources of the rings and their average properties (e.g., optical depth, particle size range and vertical distribution). In order to deal with the shadowing at specific geometries, the model uses the ray-tracing technique. The goal is to describe the ring temperatures observed by the Composite Infrared Spectrometer, CIRS, onboard the Cassini spacecraft, which is in orbit around Saturn since 2004. So far, the model is able to reproduce some of the general features of specific regions of the A, B and C rings.

  19. Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders.

    PubMed

    Szmyt, Wojciech; Guerra, Carlos; Utke, Ivo

    2017-01-01

    In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires) as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i) the gas diffusion coefficient inside such arrays, (ii) the time between collisions of molecules with the nanocylinder walls (mean time of flight), (iii) the surface impingement rate, and (iv) the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes.

  20. Diffusion of dilute gas in arrays of randomly distributed, vertically aligned, high-aspect-ratio cylinders

    PubMed Central

    Guerra, Carlos

    2017-01-01

    In this work we modelled the diffusive transport of a dilute gas along arrays of randomly distributed, vertically aligned nanocylinders (nanotubes or nanowires) as opposed to gas diffusion in long pores, which is described by the well-known Knudsen theory. Analytical expressions for (i) the gas diffusion coefficient inside such arrays, (ii) the time between collisions of molecules with the nanocylinder walls (mean time of flight), (iii) the surface impingement rate, and (iv) the Knudsen number of such a system were rigidly derived based on a random-walk model of a molecule that undergoes memoryless, diffusive reflections from nanocylinder walls assuming the molecular regime of gas transport. It can be specifically shown that the gas diffusion coefficient inside such arrays is inversely proportional to the areal density of cylinders and their mean diameter. An example calculation of a diffusion coefficient is delivered for a system of titanium isopropoxide molecules diffusing between vertically aligned carbon nanotubes. Our findings are important for the correct modelling and optimisation of gas-based deposition techniques, such as atomic layer deposition or chemical vapour deposition, frequently used for surface functionalisation of high-aspect-ratio nanocylinder arrays in solar cells and energy storage applications. Furthermore, gas sensing devices with high-aspect-ratio nanocylinder arrays and the growth of vertically aligned carbon nanotubes need the fundamental understanding and precise modelling of gas transport to optimise such processes. PMID:28144565

  1. Angular Momentum Distribution of Hot Gas and Implications for Disk Galaxy Formation

    NASA Astrophysics Data System (ADS)

    Chen, D. N.; Jing, Y. P.; Yoshikaw, Kohji

    2003-11-01

    We study the angular momentum profiles both for dark matter and for gas within virialized halos using a statistical sample of halos drawn from cosmological hydrodynamics simulations. Three simulations have been analyzed: one is the nonradiative simulation and the other two have radiative cooling. We find that the gas component, on average, has a larger spin and contains a smaller fraction of mass with negative angular momentum than its dark matter counterpart in the nonradiative model. As to the cooling models, the gas component shares approximately the same spin parameter as its dark matter counterpart, but the hot gas has a higher spin and is more aligned in angular momentum than dark matter, while the opposite holds for the cold gas. After the mass of negative angular momentum is excluded, the angular momentum profile of the hot gas component approximately follows the universal function originally proposed by Bullock et al. for dark matter, though the shape parameter μ is much larger for hot gas and is comfortably in the range required by observations of disk galaxies. Since disk formation is related to the distribution of hot gas that will cool, our study may explain the fact that the disk component of observed galaxies contains a smaller fraction of low angular momentum material than dark matter in halos.

  2. Quality of the log-geometric distribution extrapolation for smaller undiscovered oil and gas pool size

    USGS Publications Warehouse

    Chenglin, L.; Charpentier, R.R.

    2010-01-01

    The U.S. Geological Survey procedure for the estimation of the general form of the parent distribution requires that the parameters of the log-geometric distribution be calculated and analyzed for the sensitivity of these parameters to different conditions. In this study, we derive the shape factor of a log-geometric distribution from the ratio of frequencies between adjacent bins. The shape factor has a log straight-line relationship with the ratio of frequencies. Additionally, the calculation equations of a ratio of the mean size to the lower size-class boundary are deduced. For a specific log-geometric distribution, we find that the ratio of the mean size to the lower size-class boundary is the same. We apply our analysis to simulations based on oil and gas pool distributions from four petroleum systems of Alberta, Canada and four generated distributions. Each petroleum system in Alberta has a different shape factor. Generally, the shape factors in the four petroleum systems stabilize with the increase of discovered pool numbers. For a log-geometric distribution, the shape factor becomes stable when discovered pool numbers exceed 50 and the shape factor is influenced by the exploration efficiency when the exploration efficiency is less than 1. The simulation results show that calculated shape factors increase with those of the parent distributions, and undiscovered oil and gas resources estimated through the log-geometric distribution extrapolation are smaller than the actual values. ?? 2010 International Association for Mathematical Geology.

  3. Fractal analysis of the dark matter and gas distributions in the Mare-Nostrum universe

    SciTech Connect

    Gaite, José

    2010-03-01

    We develop a method of multifractal analysis of N-body cosmological simulations that improves on the customary counts-in-cells method by taking special care of the effects of discreteness and large scale homogeneity. The analysis of the Mare-Nostrum simulation with our method provides strong evidence of self-similar multifractal distributions of dark matter and gas, with a halo mass function that is of Press-Schechter type but has a power-law exponent -2, as corresponds to a multifractal. Furthermore, our analysis shows that the dark matter and gas distributions are indistinguishable as multifractals. To determine if there is any gas biasing, we calculate the cross-correlation coefficient, with negative but inconclusive results. Hence, we develop an effective Bayesian analysis connected with information theory, which clearly demonstrates that the gas is biased in a long range of scales, up to the scale of homogeneity. However, entropic measures related to the Bayesian analysis show that this gas bias is small (in a precise sense) and is such that the fractal singularities of both distributions coincide and are identical. We conclude that this common multifractal cosmic web structure is determined by the dynamics and is independent of the initial conditions.

  4. Gas Chromatographic Verification of a Mathematical Model: Product Distribution Following Methanolysis Reactions.

    ERIC Educational Resources Information Center

    Lam, R. B.; And Others

    1983-01-01

    Investigated application of binomial statistics to equilibrium distribution of ester systems by employing gas chromatography to verify the mathematical model used. Discusses model development and experimental techniques, indicating the model enables a straightforward extension to symmetrical polyfunctional esters and presents a mathematical basis…

  5. Ecosystem Warming Affects Vertical Distribution of Leaf Gas Exchange Properties and Water Relations of Spring Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The vertical distribution of gas exchange and water relations responses to full-season in situ infrared (IR) warming were evaluated for hard red spring wheat (Triticum aestivum L. cv. Yecora Rojo) grown in an open field in a semiarid desert region of the Southwest USA. A Temperature Free-Air Contro...

  6. Catalogue of the main gas manifestations in the Hellenic territory: a first step towards the estimation of the nationwide geogenic gas output

    NASA Astrophysics Data System (ADS)

    Daskalopoulou, Kyriaki; D'Alessandro, Walter; Calabrese, Sergio; Kyriakopoulos, Konstantinos; Parello, Franco

    2015-04-01

    Quantification of gaseous emissions in geological systems is an important branch because it is a major source of greenhouse gas to the atmospheric budget. Of geological environments, there are two different categories: the first category includes emissions of the predominant carbon dioxide (CO2), while the second includes emissions of the predominant methane (CH4). The Hellenic territory has a very complex geodynamic setting deriving from a long and complicated geological history. It is strongly characterized by intense seismic activity and enhanced geothermal gradient. This activity, with the contribution of an active volcanic arc, favours the existence of many cold and thermal gas manifestations. Geogenic sources release huge amounts of gases, which, apart from having important influences on the global climate, could also have a strong impact on human health. Geochemical studies based on the isotopic composition of carbon and hydrogen, along with helium isotopic ratios have become a good indicator of the origin of the gas. The isotopic ratio 13C/12C of CO2 expressed in δ 13C (‰), provides important information about the amount of CO2 released from the Earth's crust or mantle. For methane, carbon and hydrogen isotopic compositions and C1/(C2+C3) hydrocarbon ratios can characterize the origin of methane: biogenic (thermogenic or microbial) or abiogenic. Helium isotopic ratios provide additional information about crustal or mantle origin of the gas. In the present work, a large set of chemical and isotopic data is presented aiming at the identification of areas with geogenic gas emissions and their characterization in terms of different gas composition and origin. The present catalogue should be the base for the estimation total nationwide geogenic CO2 and CH4 fluxes.

  7. Phase behavior and splitting analysis: An operational tool in gas transmission and distribution

    SciTech Connect

    Martinez A., F.F.; Infantini S., M.

    1998-12-31

    Most of the natural gas produced by Petroleos de Venezuela, S.A. (PDVSA) is associated gas that flows from the gathering systems to the processing plants, before it arrives at the transmission systems. Even if the gas transmission occurs after the necessary processing of the gas has been completed, condensation still happens in the transmission, regulating stations and/or distribution systems. The quantity of condensate will not only depend on composition, pressure and temperature, but also on the unequal splitting phenomenon that takes place at tee junctions in a network system. The splitting phenomenon determines the liquid distribution at the junction. This situation is more drastic when the processing plant is partially or totally shut down in a maintenance program. This work shows how the gas transmission and distribution engineer has to use the phase behavior and splitting analysis as an operational tool, in order to predict and prevent the presence of liquid in the system. Using process simulators, the phase behavior analysis is conducted to determine the bubble and dew point curve and to perform flash calculations at any pressure and temperature. Then, the operational pressure-temperature profile is over-plotted on the phase envelope diagram in order to evaluate the condensation possibility into the gas pipeline. Afterwards, the pressure and temperature drops in regulating stations are incorporated in the phase envelope diagram and the two-phase gas condensate study is completed. Finally, considering the concepts of the splitting phenomenon and the knowledge that it can really happen, the presence of liquid in particular customers can be explained and solved. Operational experiences are included to evaluate the methodology and to present the effectiveness of the results.

  8. Diffused waveguiding capillary tube with distributed feedback for a gas laser

    NASA Technical Reports Server (NTRS)

    Elachi, C. (Inventor)

    1976-01-01

    For use in a waveguide gas laser, a capillary tube of glass or ceramic has an inner surface defining a longitudinal capillary opening through which the laser gas flows. At least a portion of the inner surface is corrugated with corrugations or channels with a periodicity Lambda where Lambda = 1/2 Lambda, Lambda being the laser gas wavelength. The tube includes a diffused region extending outwardly from the opening. The diffused region of a depth d on the order of 1 Lambda to 3 Lambda acts as a waveguide for the waves, with the corrugations producing distributed feedback. The evanescent component of the waves traveling in the diffused region interact with the laser gas in the opening, gaining energy, and thereby amplifying the waves travelling in the diffused region, which exit the diffused region, surrounding the opening, as a beam of wavelength Lambda.

  9. Probing Milky Way's hot gas halo density distribution using the dispersion measure of pulsars

    NASA Astrophysics Data System (ADS)

    Zhezher, Ya. V.; Nugaev, E. Ya.; Rubtsov, G. I.

    2016-03-01

    A number of recent studies indicates a significant amount of ionized gas in a form of the hot gas halo around the Milky Way. The halo extends over the region of 100 kpc and may be acountable for the missing baryon mass. In this paper we calculate the contribution of the proposed halo to the dispersion measure (DM) of the pulsars. The Navarro, Frenk, and White (NFW), Maller and Bullock (MB), and Feldmann, Hooper, and Gnedin (FHG) density distibutions are considered for the gas halo. The data set includes pulsars with the distance known independently from the DM, e.g., pulsars in globular clusters, LMC, SMC and pulsars with known parallax. The results exclude the NFW distribution for the hot gas, while the more realisticMB and FHG models are compatible with the observed dispersion measure.

  10. Spring foraging distribution and habitat selection by Double-crested Cormorants on the Penobscot River, Maine USA

    USGS Publications Warehouse

    Blackwell, B.F.; Krohn, W.B.

    1997-01-01

    Restoration of the Atlantic salmon (Salmo salar) to New England rivers requires, in part, an understanding of the use of habitat and prey by potential and known predators. We examined variation in habitat use by Double-crested Cormorants (Phalacrocorax auritius), from April through June 1992-94 on ca. 288 km of the 2 primary tributaries and the mainstem of the Penobscot River, Maine. Our objectives were to quantify temporal and spatial variation in habitat use and test for selection of spring foraging habitats by cormorants. Cormorants forage during daylight hours only. To determine the distribution of foraging birds we conducted aerial surveys at intervals of 105 km north of the mouth of the mainstem. However, from late April through early June of all years, birds selected (P < 0.05) 4 of the 5 mainstem dams and the estuarine portion of the river. Cormorant use of dams remained at or above expected levels until the second week of June in all years. We suggest that cormorant selection for foraging areas adjacent to dams reflected a higher availability of prey, possibly due to delay and injury of migrating Atlantic salmon smolts. Cormorant selection of the estuarine portion of the Penobscot River was likely a response to a seasonally increasing availability and abundance of estuarine and marine prey, in addition to resident freshwater species and migrating smolts.

  11. Multi-risk assessment of L'Aquila gas distribution network

    NASA Astrophysics Data System (ADS)

    Esposito, S.; Iervolino, I.; Silvestri, F.; d'Onofrio, A.; Santo, A.; Franchin, P.; Cavalieri, F.

    2012-04-01

    This study focuses on the assessment of seismic risk for gas distribution networks. The basic function of a gas system is to deliver gas from sources to costumers and it is essentially composed of pipelines, reduction stations, and demand nodes, which are connected to end users to which the lifeline delivers gas. Because most of the components are spatially distributed and buried, seismic hazard has to account for both spatial correlation of ground motion intensity measures and effects induced by permanent ground deformation such as liquefaction and landslide, which determine localized ground failure. Different performance measures are considered in the study for the network, in terms of connectivity and flow reduction. Part of the gas distribution network operating in L'Aquila (central Italy), operated by ENEL Rete Gas spa has been chosen as case study. The whole network is distributed via a 621 km pipeline network: 234 km of pipes operating at medium pressure and the remaining 387 km with gas flowing at low pressure; it also consists of Metering/Pressure reduction stations, Reduction Groups and demand nodes. The framework presented makes use of probabilistic seismic hazard analysis, both in terms of ground motion and permanent ground deformation, empirical relations to estimate pipeline response, fragility curves for the evaluation of reduction cabins vulnerability, performance indicators to characterize the functionality of the gas network. The analysis were performed through a computer code specific for risk assessment of distributed systems developed by the authors. Probabilistic hazard scenarios have been simulated for the region covering the case study considering the Paganica fault on which L'Aquila 2009 earthquake was originated as source. The strong motion has been evaluated using an European ground motion prediction equation and an associated spatial correlation model. Regarding geotechnical hazards the landslide potential of L'Aquila region, according

  12. Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

    NASA Astrophysics Data System (ADS)

    Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

    2010-12-01

    Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

  13. Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode.

    PubMed

    Poehlmann, Flavio R; Cappelli, Mark A; Rieker, Gregory B

    2010-12-01

    Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively.

  14. Current distribution measurements inside an electromagnetic plasma gun operated in a gas-puff mode

    PubMed Central

    Poehlmann, Flavio R.; Cappelli, Mark A.; Rieker, Gregory B.

    2010-01-01

    Measurements are presented of the time-dependent current distribution inside a coaxial electromagnetic plasma gun. The measurements are carried out using an array of six axially distributed dual-Rogowski coils in a balanced circuit configuration. The radial current distributions indicate that operation in the gas-puff mode, i.e., the mode in which the electrode voltage is applied before injection of the gas, results in a stationary ionization front consistent with the presence of a plasma deflagration. The effects of varying the bank capacitance, transmission line inductance, and applied electrode voltage were studied over the range from 14 to 112 μF, 50 to 200 nH, and 1 to 3 kV, respectively. PMID:21267082

  15. The GTE-65 gas turbine unit: Rig tests of the main components, possibilities of use and lines of further improvement

    NASA Astrophysics Data System (ADS)

    Lebedev, A. S.; Simin, N. O.; Petrenya, Yu. K.; Mikhailov, V. E.

    2008-04-01

    This paper is a continuation of publication [1] on the project of a GTE-65 medium-capacity power-generating gas-turbine unit and describes rig tests of its components: the compressor, the turbine’s cooled blades, and the combustion chamber. Alternative versions for possible use of the GTE-65 unit in the schemes of combined-cycle plants and its further improvement are described.

  16. Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge: Constraints from ODP Leg 204

    USGS Publications Warehouse

    Trehu, A.M.; Long, P.E.; Torres, M.E.; Bohrmann, G.; Rack, F.R.; Collett, T.S.; Goldberg, D.S.; Milkov, A.V.; Riedel, M.; Schultheiss, P.; Bangs, N.L.; Barr, S.R.; Borowski, W.S.; Claypool, G.E.; Delwiche, M.E.; Dickens, G.R.; Gracia, E.; Guerin, G.; Holland, M.; Johnson, J.E.; Lee, Y.-J.; Liu, C.-S.; Su, X.; Teichert, B.; Tomaru, H.; Vanneste, M.; Watanabe, M. E.; Weinberger, J.L.

    2004-01-01

    Large uncertainties about the energy resource potential and role in global climate change of gas hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, we sampled the gas hydrate stability zone (GHSZ) from the seafloor to its base in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of gas hydrate in this structural system. We conclude that high gas hydrate content (30-40% of pore space or 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs. Elsewhere, the average gas hydrate content of the sediments in the gas hydrate stability zone is generally <2% of the pore space, although this estimate may increase by a factor of 2 when patchy zones of locally higher gas hydrate content are included in the calculation. These patchy zones are structurally and stratigraphically controlled, contain up to 20% hydrate in the pore space when averaged over zones ???10 m thick, and may occur in up to ???20% of the region imaged by 3D seismic data. This heterogeneous gas hydrate distribution is an important constraint on models of gas hydrate formation in marine sediments and the response of the sediments to tectonic and environmental change. ?? 2004 Published by Elsevier B.V.

  17. Distribution and controls on gas hydrate in the ocean-floor environment

    SciTech Connect

    Dillon, W.P.

    1995-12-31

    Methane hydrate, a crystalline solid that is formed of water and gas molecules, is widespread in oceanic sediments. It occurs at water depths that exceed 300 to 500 m and in a zone that commonly extends from the sea floor, down several hundred meters - the base of the zone is limited by increased temperature. To determine factors that control gas hydrate concentration, we have mapped its distribution off the U.S. Atlantic coast using acoustic remote-sensing methods. Most natural gas hydrate is formed from biogenic methane, and therefore it is concentrated where there is a rapid accumulation of organic detritus and also where there is a rapid accumulation of sediments (which protect detritus from oxidation). When hydrate fills the pore space of sediment, it can reduce permeability and create a gas trap. Such trapping of gas beneath hydrate may cause the formation of the most concentrated hydrate deposits, perhaps because the gas that is held in the trap can slowly diffuse upwards or migrate through faults. Hydrate-sealed traps are formed by hills on the sea floor, by dipping strata, or by salt(?) domes. Off the southeastern United States, a small area (only 3000 km{sup 2}) beneath a ridge formed by rapidly-deposited sediments appears to contain a volume of methane in hydrate that is equivalent to {approximately}30 times the U.S. annual consumption of gas. The breakdown of hydrate can cause submarine landslides by converting the hydrate to gas plus water and generating a rise of pore pressure. Conversely, sea-floor landslides can cause breakdown of hydrate by reducing the pressure in sediments. These interacting processes may cause cascading slides, which would result in breakdown of hydrate and release of methane to the atmosphere. This addition of methane to the global greenhouse would significantly influence climate. Gas hydrate in sea-floor sediments is potentially significant to climate, energy resources, and sea-floor stability.

  18. Distribution and origin of groundwater methane in the Wattenberg oil and gas field of northern Colorado.

    PubMed

    Li, Huishu; Carlson, Kenneth H

    2014-01-01

    Public concerns over potential environmental contamination associated with oil and gas well drilling and fracturing in the Wattenberg field in northeast Colorado are increasing. One of the issues of concern is the migration of oil, gas, or produced water to a groundwater aquifer resulting in contamination of drinking water. Since methane is the major component of natural gas and it can be dissolved and transported with groundwater, stray gas in aquifers has elicited attention. The initial step toward understanding the environmental impacts of oil and gas activities, such as well drilling and fracturing, is to determine the occurrence, where it is and where it came from. In this study, groundwater methane data that has been collected in response to a relatively new regulation in Colorado is analyzed. Dissolved methane was detected in 78% of groundwater wells with an average concentration of 4.0 mg/L and a range of 0-37.1 mg/L. Greater than 95% of the methane found in groundwater wells was classified as having a microbial origin, and there was minimal overlap between the C and H isotopic characterization of the produced gas and dissolved methane measured in the aquifer. Neither density of oil/gas wells nor distance to oil/gas wells had a significant impact on methane concentration suggesting other important factors were influencing methane generation and distribution. Thermogenic methane was detected in two aquifer wells indicating a potential contamination pathway from the producing formation, but microbial-origin gas was by far the predominant source of dissolved methane in the Wattenberg field.

  19. Three-dimensional distribution of gas hydrate beneath southern Hydrate Ridge: constraints from ODP Leg 204

    NASA Astrophysics Data System (ADS)

    Tréhu, A. M.; Long, P. E.; Torres, M. E.; Bohrmann, G.; Rack, F. R.; Collett, T. S.; Goldberg, D. S.; Milkov, A. V.; Riedel, M.; Schultheiss, P.; Bangs, N. L.; Barr, S. R.; Borowski, W. S.; Claypool, G. E.; Delwiche, M. E.; Dickens, G. R.; Gracia, E.; Guerin, G.; Holland, M.; Johnson, J. E.; Lee, Y.-J.; Liu, C.-S.; Su, X.; Teichert, B.; Tomaru, H.; Vanneste, M.; Watanabe, M.; Weinberger, J. L.

    2004-06-01

    Large uncertainties about the energy resource potential and role in global climate change of gas hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, we sampled the gas hydrate stability zone (GHSZ) from the seafloor to its base in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of gas hydrate in this structural system. We conclude that high gas hydrate content (30-40% of pore space or 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs. Elsewhere, the average gas hydrate content of the sediments in the gas hydrate stability zone is generally <2% of the pore space, although this estimate may increase by a factor of 2 when patchy zones of locally higher gas hydrate content are included in the calculation. These patchy zones are structurally and stratigraphically controlled, contain up to 20% hydrate in the pore space when averaged over zones ˜10 m thick, and may occur in up to ˜20% of the region imaged by 3D seismic data. This heterogeneous gas hydrate distribution is an important constraint on models of gas hydrate formation in marine sediments and the response of the sediments to tectonic and environmental change.

  20. Numerical Study of the Gas Distribution in an Oxygen Blast Furnace. Part 2: Effects of the Design and Operating Parameters

    NASA Astrophysics Data System (ADS)

    Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng

    2015-09-01

    Gas distribution plays a significant role in an oxygen blast furnace. The uneven distribution of recycling gas from the shaft tuyere has been shown to affect the heat distribution and energy utilization in an oxygen blast furnace. Therefore, the optimal design and operating parameters beneficial to the gas distribution in an oxygen blast furnace should be determined. In total, three parameters and 22 different conditions in an oxygen blast furnace multifluid model were considered. The gas and heat distributions in an oxygen blast furnace under different conditions were simulated and compared. The study revealed that when the height of shaft tuyere decreased from 7.8 m to 3.8 m, the difference in top gas CO concentration between the center and edge decreased by 11.6%. When the recycling gas temperature increased from 1123 K to 1473 K, the difference in the top gas CO concentration between the center and edge decreased by 3.9%. As the allocation ratio increased from 0.90 to 1.94, the difference in the top gas CO concentration between the center and edge decreased by 3.0%. Considering both gas and heat distributions, a shaft tuyere height of 3.8 m to 4.8 m, a recycling gas temperature of 1473 K and an allocation ratio of 1.94 are recommended in practice under the conditions of this study.

  1. 76 FR 77223 - SourceGas Distribution LLC; Notice of Petition for Rate Approval and Revised Statement of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission SourceGas Distribution LLC; Notice of Petition for Rate Approval and Revised Statement of Operating Conditions Take notice that on December 1, 2011, SourceGas Distribution LLC...

  2. Influence of Permian salt dissolution on distribution of shallow Niobrara gas fields, eastern Colorado

    SciTech Connect

    Oldham, D.W.; Smosna, R.A.

    1996-06-01

    Subsurface analysis of Permian salt and related strata in the shallow Niobrara gas area on the eastern flank of the Denver basin reveals that the location of faulted anticlines which produce gas from porous chalk is related to the occurrence of six Nippewalla Group (Leonardian) salt zones. Salt distribution is controlled by the configuration of evaporate basins during the Leonardian, truncation at a sub-Jurassic unconformity (which has completely removed Guadalupian salts), and post-Jurassic subsurface dissolution. Significant dissolution took place in response to Laramide orogeny and subsequent eastward regional groundwater flow within the Lyons (Cedar Hills) Sandstone aquifer. Initially, dissolution occurred along a regional facies change from sandstone to salt. Solution collapse allowed for cross-formational flow and removal of younger salts. Shallow Niobrara gas fields are situated above salt outliers or along regionally updip salt edges. No significant Niobrara production exists in areas where salt is absent. Structural relief across fields is related to Leonardian thickness variations, rather than subsalt offset. Seismic data reveal abrupt Leonardian thinning at the regionally updip limit of Eckley field, which has produced over 33 BCFG. Thickness of residual salt may be important in controlling the amount of gas trapped within the Niobrara. Where thick salts are preserved, structural relief is greater, the gas-water transition zone is thicker, and gas saturation is higher at the crests of faulted anticlines.

  3. Central Appalachian basin natural gas database: distribution, composition, and origin of natural gases

    USGS Publications Warehouse

    Román Colón, Yomayra A.; Ruppert, Leslie F.

    2015-01-01

    The U.S. Geological Survey (USGS) has compiled a database consisting of three worksheets of central Appalachian basin natural gas analyses and isotopic compositions from published and unpublished sources of 1,282 gas samples from Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The database includes field and reservoir names, well and State identification number, selected geologic reservoir properties, and the composition of natural gases (methane; ethane; propane; butane, iso-butane [i-butane]; normal butane [n-butane]; iso-pentane [i-pentane]; normal pentane [n-pentane]; cyclohexane, and hexanes). In the first worksheet, location and American Petroleum Institute (API) numbers from public or published sources are provided for 1,231 of the 1,282 gas samples. A second worksheet of 186 gas samples was compiled from published sources and augmented with public location information and contains carbon, hydrogen, and nitrogen isotopic measurements of natural gas. The third worksheet is a key for all abbreviations in the database. The database can be used to better constrain the stratigraphic distribution, composition, and origin of natural gas in the central Appalachian basin.

  4. Distribution of Zeros and the Equation of State. IV ---Ideal Bose-Einstein Gas---

    NASA Astrophysics Data System (ADS)

    Ikeda, K.

    1982-09-01

    The ideal Bose-Einstein gas is investigated on the basis of the fundamental concept of the distribution of zeros of the grand partition function on the complex z(= activity) plane. For this gas there are no zeros; but poles play essentially the same role as zeros from an analytical point of view, and are distributed on the part of the positive real axis from λ-3(>0) to +∞, where λ=h(2π mkT)-1/2. The distribution function of poles is calculated, and the function-theoretical structure of the equation of state is discussed. The Bose-Einstein condensation (especially the continuity of the slope of the p-v isotherm at the condensation point and the continuity of the specific heat at the transition temperature) is examined from the point of view of the distribution of poles. From the same point of view the two-dimensional and one-dimensional ideal Bose-Einstein gases are treated. Finally, the n-dimensional (n≥ 4) ideal Bose-Einstein gas is discussed, and it is shown that for n≥ 5 the specific heat is discontinuous at the transition temperature.

  5. The effect of gas double-dynamic on mass distribution in solid-state fermentation.

    PubMed

    Chen, Hong-Zhang; Zhao, Zhi-Min; Li, Hong-Qiang

    2014-05-10

    The mass distribution regularity in substrate of solid-state fermentation (SSF) has rarely been reported due to the heterogeneity of solid medium and the lack of suitable instrument and method, which limited the comprehensive analysis and enhancement of the SSF performance. In this work, the distributions of water, biomass, and fermentation product in different medium depths of SSF were determined using near-infrared spectroscopy (NIRS) and the developed models. Based on the mass distribution regularity, the effects of gas double-dynamic on heat transfer, microbial growth and metabolism, and product distribution gradient were systematically investigated. Results indicated that the maximum temperature of substrate and the maximum carbon dioxide evolution rate (CER) were 39.5°C and 2.48mg/(hg) under static aeration solid-state fermentation (SASSF) and 33.9°C and 5.38mg/(hg) under gas double-dynamic solid-state fermentation (GDSSF), respectively, with the environmental temperature for fermentation of 30±1°C. The fermentation production (cellulase activity) ratios of the upper, middle, and lower levels were 1:0.90:0.78 at seventh day under SASSF and 1:0.95:0.89 at fifth day under GDSSF. Therefore, combined with NIRS analysis, gas double-dynamic could effectively strengthen the solid-state fermentation performance due to the enhancement of heat transfer, the stimulation of microbial metabolism and the increase of the homogeneity of fermentation products.

  6. Distribution of Organophosphate Esters between the Gas and Particle Phase-Model Predictions vs Measured Data.

    PubMed

    Sühring, Roxana; Wolschke, Hendrik; Diamond, Miriam L; Jantunen, Liisa M; Scheringer, Martin

    2016-07-05

    Gas-particle partitioning is one of the key factors that affect the environmental fate of semivolatile organic chemicals. Many organophosphate esters (OPEs) have been reported to primarily partition to particles in the atmosphere. However, because of the wide range of their physicochemical properties, it is unlikely that OPEs are mainly in the particle phase "as a class". We compared gas-particle partitioning predictions for 32 OPEs made by the commonly used OECD POV and LRTP Screening Tool ("the Tool") with the partitioning models of Junge-Pankow (J-P) and Harner-Bidleman (H-B), as well as recently measured data on OPE gas-particle partitioning. The results indicate that half of the tested OPEs partition into the gas phase. Partitioning into the gas phase seems to be determined by an octanol-air partition coefficient (log KOA) < 10 and a subcooled liquid vapor pressure (log PL) > -5 (PL in Pa), as well as the total suspended particle concentration (TSP) in the sampling area. The uncertainty of the physicochemical property data of the OPEs did not change this estimate. Furthermore, the predictions by the Tool, J-P- and H-B-models agreed with recently measured OPE gas-particle partitioning.

  7. Phthalate esters in main source water and drinking water of Zhejiang Province (China): Distribution and health risks.

    PubMed

    Wang, Xiaofeng; Lou, Xiaoming; Zhang, Nianhua; Ding, Gangqiang; Chen, Zhijian; Xu, Peiwei; Wu, Lizhi; Cai, Jianmin; Han, Jianlong; Qiu, Xueting

    2015-10-01

    To evaluate the distributions and health risks of phthalate esters in the main source water and corresponding drinking water of Zhejiang Province, the concentrations of 16 phthalate esters in water samples from 19 sites were measured from samples taken in the dry season and wet season. The concentration of the total phthalate ester congeners in source water ranged from 1.07 μg/L to 7.12 μg/L in the wet season, from 0.01 μg/L to 1.58 μg/L in the dry season, from 1.18 μg/L to 15.28 μg/L from drinking water in the wet season, and from 0.16 μg/L to 1.86 μg/L from drinking water in the dry season. Of the 16 phthalate esters, dimethyl phthalate, dibutyl phthalate, di-(2-ethyl-hexyl) phthalate, di-iso-butyl phthalate, bis-2-n-butoxyethyl phthalate, and dicyclohexyl phthalate were present in the samples analyzed, dominated by di-iso-butyl phthalate and di-(2-ethyl-hexyl) phthalate. The concentrations of phthalate esters in the wet season were all relatively higher than those in the dry season, and the drinking water had higher concentrations of phthalate esters than source water. The phthalate ester congeners studied pose little health risk to nearby citizens. Environ Toxicol Chem 2015;34:2205-2212. © 2015 SETAC.

  8. Multiobjective optimization of water distribution systems accounting for economic cost, hydraulic reliability, and greenhouse gas emissions

    NASA Astrophysics Data System (ADS)

    Wu, Wenyan; Maier, Holger R.; Simpson, Angus R.

    2013-03-01

    In this paper, three objectives are considered for the optimization of water distribution systems (WDSs): the traditional objectives of minimizing economic cost and maximizing hydraulic reliability and the recently proposed objective of minimizing greenhouse gas (GHG) emissions. It is particularly important to include the GHG minimization objective for WDSs involving pumping into storages or water transmission systems (WTSs), as these systems are the main contributors of GHG emissions in the water industry. In order to better understand the nature of tradeoffs among these three objectives, the shape of the solution space and the location of the Pareto-optimal front in the solution space are investigated for WTSs and WDSs that include pumping into storages, and the implications of the interaction between the three objectives are explored from a practical design perspective. Through three case studies, it is found that the solution space is a U-shaped curve rather than a surface, as the tradeoffs among the three objectives are dominated by the hydraulic reliability objective. The Pareto-optimal front of real-world systems is often located at the "elbow" section and lower "arm" of the solution space (i.e., the U-shaped curve), indicating that it is more economic to increase the hydraulic reliability of these systems by increasing pipe capacity (i.e., pipe diameter) compared to increasing pumping power. Solutions having the same GHG emission level but different cost-reliability tradeoffs often exist. Therefore, the final decision needs to be made in conjunction with expert knowledge and the specific budget and reliability requirements of the system.

  9. Gas-chromatographic determination of nanogram amounts of enantiomers of nortilidine, a main metabolite of tilidine, in biological specimens.

    PubMed

    Hengy, H; Vollmer, K O; Gladigau, V

    1978-04-01

    We report a specific and sensitive method for determination of the individual optical isomers of nortilidine, a main metabolite of tilidine, with the aid of a nitrogen-sensitive detector. With N-trifluoroacetyl-L-leucyl chloride as chiral reagent, the diastereomeric derivatives of the nortilidine enantiomers could be separated and quantified in the nanogram range. Under these conditions, the enantiomers of bisnortilidine, another main metabolite of tilidine, were also separated. Investigations in rats with the enantiomers of tilidine and nortilidine indicated that no racemization occurs during N-demethylation in the organism. After oral and intravenous administration of 50 mg of tilidine.HCI to a human volunteer, identical concentrations of nortilidine enantiomers were found in the plasma.

  10. Gas hydrate and P-Wave Velocity Distribution in the Yaquina Basin at the Peruvian margin

    NASA Astrophysics Data System (ADS)

    Huebscher, C.; Gajewski, D.; Grobys, J.; Kukowski, N.; Netzeband, G.; Wagner, M.; Bialas, J.

    2003-04-01

    The lower boundary of the methane hydrate stability zone in continental margin sediments is often marked by a strong, phase reversed reflection subparallel to the seafloor, called the bottom simulating reflector (BSR). High resolution multichannel seismic (MCS) data from the Yaquina Basin offshore Peru at 8 deg S show a BSR that is varying laterally in amplitude as well as in continuity. The amplitudes of the reflections above the BSR also vary with the appearance of the BSR. Where the BSR is strong, the reflections above it are weaker compared to areas where the BSR is weak. And although the strong part of the BSR is underlain immediately by strong reflections, reflections several hundred meters beneath the BSR appear weaker than those where the BSR is weak. This variation indicates significant heterogeneity in the distribution of gas and gas hydrate in this area. Chemoherms observed at the Yaquina Basin sea floor indicate the presence of free gas in the sediments up to the seafloor. The presence of gas and gas hydrate within the sediment sequence significantly influences the P-wave velocity in the affected layers. Therefore a detailed analysis of velocity variations enables to understand the apparently different conditions for the formation of gas hydrate along the BSR and the migration paths of the free gas. Ocean bottom seismometer (OBS) data from profiles coincident with the MCS data can provide such detailed velocity depth information. Velocity analysis from OBS data included 2D-ray tracing and 1D-interval-velocity analysis by means of DIX-inversion. In order to find a trade-off between vertical resolution and minimization of errors caused by the sensitivity of the DIX' formula to velocity variations in thin layers, the data have undergone a Kirchhoff wave-equation datuming and adjacent coherence filtering was applied to the data to eliminate the one sided travel path through the water column of the OBS-observations. The derived velocity structure confirms

  11. Natural gas transmission and distribution model of the National Energy Modeling System

    SciTech Connect

    1997-02-01

    The Natural Gas Transmission and Distribution Model (NGTDM) is the component of the National Energy Modeling System (NEMS) that is used to represent the domestic natural gas transmission and distribution system. NEMS was developed in the Office of Integrated Analysis and Forecasting of the Energy Information Administration (EIA). NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the EIA and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. From 1982 through 1993, the Intermediate Future Forecasting System (IFFS) was used by the EIA for its analyses, and the Gas Analysis Modeling System (GAMS) was used within IFFS to represent natural gas markets. Prior to 1982, the Midterm Energy Forecasting System (MEFS), also referred to as the Project Independence Evaluation System (PIES), was employed. NEMS was developed to enhance and update EIA`s modeling capability by internally incorporating models of energy markets that had previously been analyzed off-line. In addition, greater structural detail in NEMS permits the analysis of a broader range of energy issues. The time horizon of NEMS is the midterm period (i.e., through 2015). In order to represent the regional differences in energy markets, the component models of NEMS function at regional levels appropriate for the markets represented, with subsequent aggregation/disaggregation to the Census Division level for reporting purposes.

  12. Genetic algorithm for the pair distribution function of the electron gas.

    PubMed

    Vericat, Fernando; Stoico, César O; Carlevaro, C Manuel; Renzi, Danilo G

    2011-12-01

    The pair distribution function of the electron gas is calculated using a parameterized generalization of hypernetted chain approximation with the parameters being obtained by optimizing the system energy with a genetic algorithm. The functions so obtained are compared with Monte Carlo simulations performed by other authors in its variational and di_usion versions showing a very good agreement especially with the di_usion Monte Carlo results.

  13. Symptoms of hand-arm vibration syndrome in gas distribution operatives

    PubMed Central

    Palmer, K.; Crane, G.; Inskip, H.

    1998-01-01

    OBJECTIVES: To survey the prevalence and severity of hand-arm vibration syndrome symptoms (HAVS), and to estimate past and current exposure to hand held vibrating tools in a sample of gas distribution operatives breaking and re-instating road surfaces. METHODS: 153 gas distribution operatives (participation rate 81%) from three company districts were assessed by an administered questionnaire, a clinical examination, and a simple cold challenge test to the hands. Exposure histories were taken aided by a picture album of past and current tools. Information was obtained from several sources on the likely vibratory characteristics of those tools. Estimates were thus obtained of the frequency of blanching and neurological complaints in operatives, and of their lifetime hours of exposure and lifetime dose of vibration. RESULTS: On average, the sample had spent 16 years in employment involving use of vibratory tools. 24% had symptoms or signs of blanching after use of tools in the industry; 46% had troublesome persistent complaints of paraesthesiae or numbness, and these symptoms extended into the hands or arms in 18% of workers. In 5.9% the distribution of symptoms was suggestive of carpal tunnel syndrome; and of ulnar nerve entrapment in a further 3.9%. The risks of blanching and neurological complaints rose significantly with lifetime hours of use of vibrating tools and lifetime dose of vibration. Symptoms were generally mild and apparent only after a prolonged interval, but there were exceptions, and cases had occurred after lower recent exposures. CONCLUSIONS: It has been suggested that aspects of the gas distribution operative's work mitigate against the risk normally anticipated from use of pneumatic road breaking tools. By contrast our data suggest that symptoms of HAVS do occur, given sufficient exposure, a finding relevant not only to gas supply workers, but also to workers from other industries who break and repair road surfaces.   PMID:9930095

  14. Fabrication of gas impervious edge seal for a bipolar gas distribution assembly for use in a fuel cell

    DOEpatents

    Kaufman, Arthur; Werth, John

    1986-01-01

    A bipolar gas reactant distribution assembly for use in a fuel cell is disclosed, the assembly having a solid edge seal to prevent leakage of gaseous reactants wherein a pair of porous plates are provided with peripheral slits generally parallel to, and spaced apart from two edges of the plate, the slit being filled with a solid, fusible, gas impervious edge sealing compound. The plates are assembled with opposite faces adjacent one another with a layer of a fusible sealant material therebetween the slits in the individual plates being approximately perpendicular to one another. The plates are bonded to each other by the simultaneous application of heat and pressure to cause a redistribution of the sealant into the pores of the adjacent plate surfaces and to cause the edge sealing compound to flow and impregnate the region of the plates adjacent the slits and comingle with the sealant layer material to form a continuous layer of sealant along the edges of the assembled plates.

  15. Altitude Investigation of Gas Temperature Distribution at Turbine of Three Similar Axial-Flow Turbojet Engines

    NASA Technical Reports Server (NTRS)

    Prince, W.R.; Schulze, F.W.

    1952-01-01

    An investigation of the effect of inlet pressure, corrected engine speed, and turbine temperature level on turbine-inlet gas temperature distributions was conducted on a J40-WE-6, interim J40-WE-6, and prototype J40-WE-8 turbojet engine in the altitude wind tunnel at the NAC.4 Lewis laboratory. The engines were investigated over a range of simulated pressure altitudes from 15,000 to 55,000 feet, flight Mach numbers from 0.12 to 0.64, and corrected engine speeds from 7198 to 8026 rpm, The gas temperature distribution at the turbine of the three engines over the range of operating conditions investigated was considered satisfactory from the standpoint of desired temperature distribution with one exception - the distribution for the J40-WE-6 engine indicated a trend with decreasing engine-inlet pressure for the temperature to exceed the desired in the region of the blade hub. Installation of a compressor-outlet mixer vane assembly remedied this undesirable temperature distribution, The experimental data have shown that turbine-inlet temperature distributions are influenced in the expected manner by changes in compressor-outlet pressure or mass-flow distribution and by changes in combustor hole-area distribution. The similarity between turbine-inlet and turbine-outlet temperature distribution indicated only a small shift in temperature distribution imposed by the turbine rotors. The attainable jet thrusts of the three engines were influenced in different degrees and directions by changes in temperature distributions with change in engine-inlet pressure. Inability to match the desired temperature distribution resulted, for the J40-WE-6 engine, in an 11-percent thrust loss based on an average turbine-inlet temperature of 1500 F at an engine-inlet pressure of 500 pounds per square foot absolute. Departure from the desired temperature distribution in the Slade tip region results, for the prototype J40-WE-8 engine, in an attainable thrust increase of 3 to 4 percent as

  16. Pressure drop and gas distribution in compost based biofilters: medium mixing and composition effects.

    PubMed

    Morgan-Sagastume, J M; Revah, S; Noyola, A

    2003-07-01

    The pressure drop and gas distribution in four different filter media for compost biofilters were studied as a function of three superficial loading rates of moist air and by carrying out the filter medium homogenization by mixing. The filter media used were compost, compost with cane bagasse, lava rock and aerobic sludge previously dried to 60% of water content. The pressure drop increased when lava rock and cane bagasse were used as bulking agents. The same trend was observed when water was added to the filter medium. Pressure drop tended to decrease with time as flow channels were formed inthe filter media. Tracer studies were carried out to quantify the gas distribution and the effect of channel formation. For the biofilters submitted to an airflow of 10, 40 and 70 l min(-1), an average normalized time of 0.96, 0.89 and 0.82, respectively were obtained. The results showed that channel formation was increased as the superficial loading rate was also increased. An operational practice that this work proposes and evaluates to improve gas distribution and medium moisture control is to carry out intermittent medium mixing. The medium moisture and void volume achieved under mixing condition were around 50% and 0.40, respectively with an average constant pressure drop of 11, 45 and 78 cm of water m(-1) for air velocities of 75, 300 and 525 m h(-1).

  17. Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip

    NASA Technical Reports Server (NTRS)

    Azad, Gm S.; Han, Je-Chin; Teng, Shuye; Boyle, Robert J.

    2000-01-01

    Heat transfer coefficient and static pressure distributions are experimentally investigated on a gas turbine blade tip in a five-bladed stationary linear cascade. The blade is a 2-dimensional model of a first stage gas turbine rotor blade with a blade tip profile of a GE-E(sup 3) aircraft gas turbine engine rotor blade. The flow condition in the test cascade corresponds to an overall pressure ratio of 1.32 and exit Reynolds number based on axial chord of 1.1 x 10(exp 6). The middle 3-blade has a variable tip gap clearance. All measurements are made at three different tip gap clearances of about 1%, 1.5%, and 2.5% of the blade span. Heat transfer measurements are also made at two different turbulence intensity levels of 6.1 % and 9.7% at the cascade inlet. Static pressure measurements are made in the mid-span and the near-tip regions as well as on the shroud surface, opposite the blade tip surface. Detailed heat transfer coefficient distributions on the plane tip surface are measured using a transient liquid crystal technique. Results show various regions of high and low heat transfer coefficient on the tip surface. Tip clearance has a significant influence on local tip beat transfer coefficient distribution. Heat transfer coefficient also increases about 15-20% along the leakage flow path at higher turbulence intensity level of 9.7% over 6.1 %.

  18. Exterior Distribution of Utility Steam, High Temperature Water (HTW), Chilled Water (CHW), Fuel Gas, and Compressed Air.

    DTIC Science & Technology

    1981-07-01

    A~r-AIIO 408 NAVAL FACILITIES ENGINEERING COMMAND ALEXANDRIA VA FIG 13/11 EXTERIOR DISTRIBUTION OF UTILITY STEAM. HIGH TEMPERATURE WATER -ETC(U...PUBUC RELEASE JOF EXTERIOR DISTRIBUTION OF O UTILITY STEAM, HIGH 0 TEMPERATURE WATER (HTW), , CHILLED WATER (CHW), FUEL GAS, AND COMPRESSED AIR DESIGN...distribution piping system for supplying utility steam, high temperature water (HTW), chilled water (CRW), cooling or condensing water, fuel gas, and

  19. Linking basin-scale and pore-scale gas hydrate distribution patterns in diffusion-dominated marine hydrate systems

    NASA Astrophysics Data System (ADS)

    Nole, Michael; Daigle, Hugh; Cook, Ann E.; Hillman, Jess I. T.; Malinverno, Alberto

    2017-02-01

    The goal of this study is to computationally determine the potential distribution patterns of diffusion-driven methane hydrate accumulations in coarse-grained marine sediments. Diffusion of dissolved methane in marine gas hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate distribution patterns at the scale of individual sand layers (1-20 m thick) that are deposited between microbially active fine-grained material buried through the gas hydrate stability zone (GHSZ). We then extrapolate to two-dimensional and basin-scale three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including pore size distribution, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the distribution of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin gas hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. Furthermore, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.main</span>">Plain Language SummaryThis study combines one-, two-, and three-dimensional simulations to explore one potential process by which methane dissolved in water beneath the seafloor can be converted into solid methane hydrate. This work specifically</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21313756','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21313756"><span>DETERMINING ALL <span class="hlt">GAS</span> PROPERTIES IN GALAXY CLUSTERS FROM THE DARK MATTER <span class="hlt">DISTRIBUTION</span> ALONE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Frederiksen, Teddy F.; Hansen, Steen H.; Host, Ole; Roncadelli, Marco</p> <p>2009-08-01</p> <p>We demonstrate that all properties of the hot X-ray emitting <span class="hlt">gas</span> in galaxy clusters are completely determined by the underlying dark matter (DM) structure. Apart from the standard conditions of spherical symmetry and hydrostatic equilibrium for the <span class="hlt">gas</span>, our proof is based on the Jeans equation for the DM and two simple relations which have recently emerged from numerical simulations: the equality of the <span class="hlt">gas</span> and DM temperatures, and the almost linear relation between the DM velocity anisotropy profile and its density slope. For DM <span class="hlt">distributions</span> described by the Navarro-Frenk-White or the Sersic profiles, the resulting <span class="hlt">gas</span> density profile, the <span class="hlt">gas</span>-to-total-mass ratio profile, and the entropy profile are all in good agreement with X-ray observations. All these profiles are derived using zero free parameters. Our result allows us to predict the X-ray luminosity profile of a cluster in terms of its DM content alone. As a consequence, a new strategy becomes available to constrain the DM morphology in galaxy clusters from X-ray observations. Our results can also be used as a practical tool for creating initial conditions for realistic cosmological structures to be used in numerical simulations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A23P..05L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A23P..05L"><span>Mobile Methane Measurements of Natural <span class="hlt">Gas</span> <span class="hlt">Distribution</span> and End-use Emissions in Indianapolis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lamb, B. K.; Roscioli, J. R.; Floerchinger, C. R.; Herndon, S. C.; Ferrara, T.</p> <p>2015-12-01</p> <p>Indianapolis is the site of the INFLUX program to investigate greenhouse <span class="hlt">gas</span> emissions from a large metropolitan area. A key question in INFLUX is the relative contributions of methane emissions from the local <span class="hlt">gas</span> <span class="hlt">distribution</span> system in comparison to biogenic sources, such as the wastewater treatment system and landfills, and of end use emissions from furnaces and other combustion devices downstream of customer <span class="hlt">gas</span> meters. During February and March, 2015, the Aerodyne van was used to measure methane, ethane, CO2 and other trace gases during mobile sampling traverses through a number of urban and suburban Indianapolis neighborhoods. Signatures of distinct natural <span class="hlt">gas</span> emissions, biogenic emissions, and combustion emissions were observed in small plumes. In a number of cases, these sources were identified as manhole covers in city streets, where nearby leaks can seep into the local wastewater system. Quantification of ethane and methane from 45 manholes reveal that some had emissions that were clearly biogenic while others had a distinct natural <span class="hlt">gas</span> signature. This paper describes the results from the analysis of these mobile data in the context of the current Indianapolis methane emission inventory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......145D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......145D"><span>Widely tunable Sampled Grating <span class="hlt">Distributed</span> Bragg Reflector Quantum Cascade laser for <span class="hlt">gas</span> spectroscopy applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diba, Abdou Salam</p> <p></p> <p>Since the advent of semiconductor lasers, the development of tunable laser sources has been subject of many efforts in industry and academia arenas. This interest towards broadly tunable lasers is <span class="hlt">mainly</span> due to the great promise they have in many applications ranging from telecommunication, to environmental science and homeland security, just to name a few. After the first demonstration of quantum cascade laser (QCL) in the early nineties, QCL has experienced a rapid development, so much so that QCLs are now the most reliable and efficient laser source in the Mid-IR range covering between 3 microm to 30 microm region of the electromagnetic spectrum. QCLs have almost all the desirable characteristics of a laser for spectroscopy applications such as narrow spectral linewidth ideal for high selectivity measurement, high power enabling high sensitivity sensing and more importantly they emit in the finger-print region of most of the trace gases and large molecules. The need for widely tunable QCLs is now more pressing than ever before. A single mode quantum cascade laser (QCL) such as a <span class="hlt">distributed</span> feedback (DFB) QCL, is an ideal light source for <span class="hlt">gas</span> sensing in the MIR wavelength range. Despite their performance and reliability, DFB QCLs are limited by their relatively narrow wavelength tuning range determined by the thermal rollover of the laser. An external cavity (EC) QCL, on the other hand, is a widely tunable laser source, and so far is the choice mid-infrared single frequency light sources for detecting multiple species/large molecules. However, EC QCLs can be complex, bulky and expensive. In the quest for finding alternative broadly wavelength tunable sources in the mid-infrared, many monolithic tunable QCLs are recently proposed and fabricated, including SG-DBR, DFB-Arrays, Slot-hole etc. and they are all of potentially of interest as a candidate for multi-<span class="hlt">gas</span> sensing and monitoring applications, due to their large tuning range (>50 cm-1), and potentially low</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22092383','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22092383"><span>JUPITER WILL BECOME A HOT JUPITER: CONSEQUENCES OF POST-<span class="hlt">MAIN</span>-SEQUENCE STELLAR EVOLUTION ON <span class="hlt">GAS</span> GIANT PLANETS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Spiegel, David S.; Madhusudhan, Nikku E-mail: Nikku.Madhusudhan@yale.edu</p> <p>2012-09-10</p> <p>When the Sun ascends the red giant branch (RGB), its luminosity will increase and all the planets will receive much greater irradiation than they do now. Jupiter, in particular, might end up more highly irradiated than the hot Neptune GJ 436b and, hence, could appropriately be termed a 'hot Jupiter'. When their stars go through the RGB or asymptotic giant branch stages, many of the currently known Jupiter-mass planets in several-AU orbits will receive levels of irradiation comparable to the hot Jupiters, which will transiently increase their atmospheric temperatures to {approx}1000 K or more. Furthermore, massive planets around post-<span class="hlt">main</span>-sequence stars could accrete a non-negligible amount of material from the enhanced stellar winds, thereby significantly altering their atmospheric chemistry as well as causing a significant accretion luminosity during the epochs of most intense stellar mass loss. Future generations of infrared observatories might be able to probe the thermal and chemical structure of such hot Jupiters' atmospheres. Finally, we argue that, unlike their <span class="hlt">main</span>-sequence analogs (whose zonal winds are thought to be organized in only a few broad, planetary-scale jets), red-giant hot Jupiters should have multiple, narrow jets of zonal winds and efficient day-night redistribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS53A1355D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS53A1355D"><span>Free <span class="hlt">gas</span> in the regional hydrate stability zone: Implications for hydrate <span class="hlt">distribution</span> and fracturing behavior</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Daigle, H.; Dugan, B.</p> <p>2010-12-01</p> <p>We show that hydrate <span class="hlt">distribution</span> and fracture genesis in the hydrate stability zone are largely governed by the phase of methane supply. In systems where methane is supplied primarily as free <span class="hlt">gas</span>, hydrate saturation increases upwards in the hydrate stability zone, and fractures nucleate in the middle of the stability zone where hydrate saturation is highest. In systems where methane is supplied primarily as a dissolved phase in the pore water, hydrate saturation decreases upwards in the stability zone, and fractures nucleate at the base of the stability zone. These interpretations are based on our one-dimensional model that incorporates multiphase flow and free <span class="hlt">gas</span> within the regional hydrate stability zone (RHSZ). The RHSZ is defined as the interval in which methane hydrate may occur at seawater salinity (3.35% by mass). As hydrate forms and excludes salt from the crystal structure, the porewater salinity increases. Free <span class="hlt">gas</span> enters the RHSZ when the porewater salinity increases to the value required for three-phase (dissolved methane + <span class="hlt">gas</span> hydrate + free <span class="hlt">gas</span>) equilibrium. Our model also incorporates changes to capillary pressure as hydrate forms and occludes the pore system. We model the system until the excess pore pressure exceeds the vertical effective stress in the domain due to capillary effects and pore occlusion, at which point we assume fractures nucleate. We test our model at Hydrate Ridge, where methane supply is dominantly in the <span class="hlt">gas</span> phase, and show that hydrate saturation increases upwards and fractures nucleate high within the stability zone, eventually allowing <span class="hlt">gas</span> to vent to the seafloor. We also model Blake Ridge, where methane supply is dominantly in the dissolved phase, and show that hydrate saturation is greatest at the base of the stability zone; fractures nucleate here and in some cases could propagate through the regional hydrate stability zone, allowing methane-charged water to vent to the seafloor. These two systems represent endmembers of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.648a2002K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.648a2002K"><span>Investigation of the causes for the measurement differences between the natural <span class="hlt">gas</span> measurement systems of a <span class="hlt">gas</span> <span class="hlt">distribution</span> company and of a consumer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kawakita, Kazuto; Silva Telles, Rubens</p> <p>2015-10-01</p> <p>This paper presents the methodology used, the checked items and the results obtained in an investigation carried out to identify the causes that generated substantial differences between the natural <span class="hlt">gas</span> volumes measured by two measuring systems, one from a <span class="hlt">gas</span> <span class="hlt">distribution</span> company and another from its industrial consumer, both installed in series in a <span class="hlt">gas</span> pipeline. The investigation showed that the measurement of the volume of <span class="hlt">gas</span> performed by the <span class="hlt">gas</span> distributor metering system was influenced by an erroneous measurement of the <span class="hlt">gas</span> temperature since it was affected by a complex thermodynamic process involving cooling by the Joule-Thomson effect caused by a pressure reducing valve and heating by heat exchange through the pipe walls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015FBS....56..801A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015FBS....56..801A"><span>Quenched Dynamics of the Momentum <span class="hlt">Distribution</span> of the Unitary Bose <span class="hlt">Gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ancilotto, Francesco; Rossi, Maurizio; Salasnich, Luca; Toigo, Flavio</p> <p>2015-12-01</p> <p>We study the quenched dynamics of the momentum <span class="hlt">distribution</span> of a unitary Bose <span class="hlt">gas</span> under isotropic harmonic confinement within a time-dependent density functional approach based on our recently calculated Monte Carlo bulk equation of state. In our calculations the inter-atomic s-wave scattering length of the trapped bosons is suddenly increased to a very large value and the real-time evolution of the system is studied. Prompted by the very recent experimental data of 85Rb atoms at unitarity (Makotyn et al. in Nat Phys 10:116, 2014) we focus on the momentum <span class="hlt">distribution</span> as a function of time. Our results suggest that at low momenta, a quasi-stationary momentum <span class="hlt">distribution</span> is reached after a long transient, contrary to what found experimentally for large momenta which equilibrate on a time scale shorter than the one for three body losses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997PhDT........85J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997PhDT........85J"><span>Regulatory reform for natural <span class="hlt">gas</span> pipelines: The effect on pipeline and <span class="hlt">distribution</span> company share prices</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jurman, Elisabeth Antonie</p> <p>1997-08-01</p> <p>The natural <span class="hlt">gas</span> shortages in the 1970s focused considerable attention on the federal government's role in altering energy consumption. For the natural <span class="hlt">gas</span> industry these shortages eventually led to the passage of the Natural <span class="hlt">Gas</span> Policy Act (NGPA) in 1978 as part of the National Energy Plan. A series of events in the decade of the 1980s has brought about the restructuring of interstate natural <span class="hlt">gas</span> pipelines which have been transformed by regulators and the courts from monopolies into competitive entities. This transformation also changed their relationship with their downstream customers, the LDCs, who no longer had to deal with pipelines as the only merchants of <span class="hlt">gas</span>. Regulatory reform made it possible for LDCs to buy directly from producers using the pipelines only for delivery of their purchases. This study tests for the existence of monopoly rents by analyzing the daily returns of natural <span class="hlt">gas</span> pipeline and utility industry stock price data from 1982 to 1990, a period of regulatory reform for the natural <span class="hlt">gas</span> industry. The study's <span class="hlt">main</span> objective is to investigate the degree of empirical support for claims that regulatory reforms increase profits in the affected industry, as the normative theory of regulation expects, or decrease profits, as advocates of the positive theory of regulation believe. I also test Norton's theory of risk which predicts that systematic risk will increase for firms undergoing deregulation. Based on a sample of twelve natural <span class="hlt">gas</span> pipelines, and 25 utilities an event study concept was employed to measure the impact of regulatory event announcements on daily natural <span class="hlt">gas</span> pipeline or utility industry stock price data using a market model regression equation. The results of this study provide some evidence that regulatory reforms did not increase the profits of pipeline firms, confirming the expectations of those who claim that excess profits result from regulation and will disappear, once that protection is removed and the firms are operating in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoMP..171...82H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoMP..171...82H"><span>Noble <span class="hlt">gas</span> composition and 40Ar/39Ar age in eclogites from the <span class="hlt">main</span> hole of the Chinese Continental Scientific Drilling project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hopp, Jens; Schwarz, Winfried H.; Trieloff, Mario; Meyer, Hans-Peter; Hanel, Michael; Altherr, Rainer</p> <p>2016-10-01</p> <p>We present the first comprehensive noble <span class="hlt">gas</span> study on eclogites. The four eclogite samples were recovered during the Chinese Continental Scientific Drilling and are from two distinct profile depth sections differing in their degree of interaction with meteoric water, based on their δ 18O-values (surface related and of mantle-type). Hence, noble <span class="hlt">gas</span> analyses offer the potential to further discriminate between shallow (meteoric) and deep (mantle) fluid sources. Noble <span class="hlt">gas</span> compositions reveal typical crustal fluid compositions, characterized by a variable mixture of atmospheric gases with significant contributions of nucleogenic neon, radiogenic 4He*, radiogenic 40Ar*, fissiogenic 131-136Xe, and presumably bariogenic 131Xe, but no significant addition of mantle gases. This signature can be also considered to represent one endmember component of eclogitic diamonds. Concentrations of non-radiogenic noble gases are rather low, with depletion of light relative to the heavier noble gases. Eclogites from lower depth which experienced a higher degree of interaction with meteoric water also showed higher contributions of atmospheric <span class="hlt">gas</span> compared with eclogites recovered from greater depth. This is interpreted to result from interaction with high-salinity fluids during ultrahigh pressure (UH P). It demonstrates that the atmospheric noble <span class="hlt">gas</span> abundance is a proxy for interaction with surface related fluids. 40Ar/39Ar (inverse) isochron ages of two phengite separates (241.2 ± 0.4 Ma and 275.0 ± 1.8 Ma, 1 σ-errors) predate the <span class="hlt">main</span> phase of UH P metamorphism (ca. 220 Ma). Biotite yields an integrated age of about 1100 Ma. These age values are interpreted to reflect the likely addition of excess 40Ar without any chronological meaning.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..GECFT2002P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..GECFT2002P"><span><span class="hlt">Gas</span> composition influence on ion energy <span class="hlt">distribution</span> functions in an industrial ICP reactor with biased cathode</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peterson, David; Shannon, Steven; Coumou, David; White, Scott</p> <p>2016-09-01</p> <p>An industrial ICP reactor consisting of a top planar coil and RF biased lower electrode has been characterized using a hairpin resonator probe and gridded ion energy analyzer to measure electron density in the bulk plasma and ion energy <span class="hlt">distribution</span> function (IEDF) at the surface of the biased cathode. Argon and oxygen were run at constant total flow with 20mTorr downstream pressure control with varying flow ratios between the two gases ranging from 0% to 100% oxygen content. ICP and bias power were adjusted to maintain constant electron density and sheath bias over this mixing matrix at four different setpoints reflecting high density / high bias, high density / low bias, low density / high bias, and low density / low bias. Although the fundamental parameters governing RF sheath behavior were held constant, several trends in ion energy <span class="hlt">distribution</span> are observed with respect to <span class="hlt">gas</span> composition (aside from the obvious influence of ion mass) that show considerable variation in measured IEDF particularly that can be attributed to ion collisions in the sheath as well as <span class="hlt">gas</span> heating variation due to <span class="hlt">gas</span> composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10182576','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10182576"><span>Integrated resource planning for local <span class="hlt">gas</span> <span class="hlt">distribution</span> companies: A critical review of regulatory policy issues</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Harunuzzaman, M.; Islam, M.</p> <p>1994-08-01</p> <p>According to the report, public utility commissions (PUCs) are increasingly adopting, or considering the adoption of integrated resource planning (IRP) for local <span class="hlt">gas</span> <span class="hlt">distribution</span> companies (LDCs). The Energy Policy Act of 1992 (EPAct) requires PUCs to consider IRP for <span class="hlt">gas</span> LDCs. This study has two major objectives: (1) to help PUCs develop appropriate regulatory approaches with regard to IRP for <span class="hlt">gas</span> LDCs; and (2) to help PUCs respond to the EPAct directive. The study finds that it is appropriate for PUCs to pursue energy efficiency within the traditional regulatory framework of minimizing private costs of energy production and delivery; and PUCs should play a limited role in addressing environmental externalities. The study also finds that in promoting energy efficiency, PUCs should pursue policies that are incentive-based, procompetitive, and sensitive to rate impacts. The study evaluates a number of traditional and nontraditional ratemaking mechanisms on the basis of cost minimization, energy efficiency, competitiveness, and other criteria. The mechanisms evaluated include direct recovery of DSM expenses, lost revenue adjustments for DSM options, revenue decoupling mechanisms, sharing of DSM cost savings, performance-based rate of return for DSM, provision of DSM as a separate service, deregulation of DSM service, price caps, and deregulation of the noncore <span class="hlt">gas</span> market. The study concludes with general recommendations for regulatory approaches and ratemaking mechanisms that PUCs may wish to consider in advancing IRP objectives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/10178521','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/10178521"><span>Market hub technology in the domestic natural <span class="hlt">gas</span> <span class="hlt">distribution</span> system. A panel discussion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Glicken, J.</p> <p>1992-09-01</p> <p>This document describes a panel discussion held on March 18, 1992 as part of a conference entitled ``Market Hub Technology`` . The purpose of the conference was to stimulate dialogue among various segments of the natural <span class="hlt">gas</span> industry on the technology limits of an economic policy issue that has the potential to significantly alter the structure and functioning of the natural <span class="hlt">gas</span> industry. Attendees included key US <span class="hlt">gas</span> industry representatives, Federal Energy Regulatory Commission (FERC) commissioners, and others. The conference explored the concept of market centers, or hubs, and related technologies. It covered the technology currently available for the establishment of an integrated system of physical market hubs, and explored technology requirements for the further development of useful and efficient hubs. The discussion identified two primary barriers to the acceptance and implementation of a market center <span class="hlt">distribution</span> system for natural <span class="hlt">gas</span>. The first barrier is the potential change in the configuration of the market such a system would introduce and the resistance various industry segments would mount to such change. The second is the lack of industry standardization in the physical and business infrastructures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982PThPh..68..471I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982PThPh..68..471I"><span><span class="hlt">Distribution</span> of Zeros and the Equation of State. III ---Cluster Series, the Ideal Fermi-Dirac <span class="hlt">Gas</span> and Other Problems---</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ikeda, K.</p> <p>1982-08-01</p> <p>The radius of convergence of the cluster series (expressing the equation of state) is discussed in connection with the <span class="hlt">distribution</span> of zeros of the grand partition function on the complex z(=activity) plane, by giving various examples of circular <span class="hlt">distribution</span>. Anomalous phase transitions and phase transitions of third order are considered by showing some examples of circular <span class="hlt">distribution</span> of zeros. For the ideal Fermi-Dirac <span class="hlt">gas</span>, the <span class="hlt">distribution</span> function of zeros, lying on the part of the negative real axis from -λ-3 to -∞ [where λ=h(2 π mkT)-1/ 2], is calculated , and the function-theoretical structure of the equation of state is investigated. The <span class="hlt">distribution</span> of zeros for this <span class="hlt">gas</span> is compared with that for Tonks' <span class="hlt">gas</span> (having purely repulsive interparticle forces). The two-dimensional and one-dimensional Fermi-Dirac gases are dealt with from the point of view of the <span class="hlt">distribution</span> of zeros.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/206943','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/206943"><span>Model documentation Natural <span class="hlt">Gas</span> Transmission and <span class="hlt">Distribution</span> Model of the National Energy Modeling System. Volume 1</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1996-02-26</p> <p>The Natural <span class="hlt">Gas</span> Transmission and <span class="hlt">Distribution</span> Model (NGTDM) of the National Energy Modeling System is developed and maintained by the Energy Information Administration (EIA), Office of Integrated Analysis and Forecasting. This report documents the archived version of the NGTDM that was used to produce the natural <span class="hlt">gas</span> forecasts presented in the Annual Energy Outlook 1996, (DOE/EIA-0383(96)). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic approach, and provides detail on the methodology employed. Previously this report represented Volume I of a two-volume set. Volume II reported on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BAAA...57..206V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BAAA...57..206V"><span>Star forming regions towards Gum 31: <span class="hlt">distribution</span> of the molecular <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vazzano, M. M.; Cappa, C. E.; Vasquez, J.; Rubio, M.</p> <p>2015-08-01</p> <p>We analyze the <span class="hlt">distribution</span> of the molecular <span class="hlt">gas</span> associated with IRAS and 2MASS sources, young stellar objects linked to the Hii region Gum31. We based our studies on observations obtained with the APEX telescope, located in the north of Chile. We used observations of different CO isotopologues, CS(7-6) and HCO(4-3) lines. The sources are located on the edge of the Gum31 Hii region, whose shock front substantially affects the morphology of their molecular environs. The observations revealed that in the surroundings of the sources there is molecular <span class="hlt">gas</span> associated with the nebula, which is shown by the CO(3-2) emission, with small high density clumps detected in CO(3-2).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhRvA..94f3651P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhRvA..94f3651P"><span>Large-momentum <span class="hlt">distribution</span> of a polarized Fermi <span class="hlt">gas</span> and p -wave contacts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peng, Shi-Guo; Liu, Xia-Ji; Hu, Hui</p> <p>2016-12-01</p> <p>We present a derivation of the adiabatic energy relations as well as the large momentum <span class="hlt">distribution</span> of a polarized Fermi <span class="hlt">gas</span> near p -wave Feshbach resonances. The leading asymptotic behavior k-2 and subleading behavior k-4 of the large momentum <span class="hlt">distribution</span> have recently been predicted by Z. Yu et al. [Phys. Rev. Lett. 115, 135304 (2015), 10.1103/PhysRevLett.115.135304] and by M. Y. He et al. [Phys. Rev. Lett. 116, 045301 (2016), 10.1103/PhysRevLett.116.045301] using two different approaches. Here, we show that the subleading asymptotic behavior (˜k-4 ) cannot fully be captured by the contact defined from the adiabatic energy relation related to the p -wave effective range, and there should be an extra term resulting from the center-of-mass motion of the pairs. The omission of this extra term is perhaps a reasonable approximation at zero temperature. However, it should be taken into account at finite temperature and should have significant importance to understand the recently measured momentum <span class="hlt">distribution</span> in a resonant p -wave Fermi <span class="hlt">gas</span> of ultracold 40K atoms [C. Luciuk et al., Nat. Phys. 12, 599 (2016), 10.1038/nphys3670].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=146370&keyword=consumer+AND+relationship+AND+management&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78738572&CFTOKEN=79287777','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=146370&keyword=consumer+AND+relationship+AND+management&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78738572&CFTOKEN=79287777"><span>THE EFFECT OF CHLORIDE AND ORTHOPHOSPHATE ON THE RELEASE OF IRON FROM DRINKING WATER <span class="hlt">DISTRIBUTION</span> SYSTEM CAST IRON <span class="hlt">MAIN</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>“Colored water” resulting from suspended iron particles is a common drinking water consumer complaint which is largely impacted by water chemistry. A bench scale study, performed on a 90 year-old corroded cast-iron pipe section removed from a drinking water <span class="hlt">distribution</span> system, w...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22215391','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22215391"><span>THE SMOOTH Mg II <span class="hlt">GAS</span> <span class="hlt">DISTRIBUTION</span> THROUGH THE INTERSTELLAR/EXTRA-PLANAR/HALO INTERFACE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kacprzak, Glenn G.; Cooke, Jeff; Ryan-Weber, Emma V.; Churchill, Christopher W.; Nielsen, Nikole M.</p> <p>2013-11-01</p> <p>We report the first measurements of Mg II absorption systems associated with spectroscopically confirmed z ∼ 0.1 star-forming galaxies at projected distances of D < 6 kpc. We demonstrate that the data are consistent with the well-known anti-correlation between rest-frame Mg II equivalent width, W{sub r} (2796), and impact parameter, D, represented by a single log-linear relation derived by Nielsen et al. (MAGIICAT) that converges to ∼2 Å at D = 0 kpc. Incorporating MAGIICAT, we find that the halo <span class="hlt">gas</span> covering fraction is unity below D ∼ 25 kpc. We also report that our D < 6 kpc absorbers are consistent with the W{sub r} (2796) <span class="hlt">distributions</span> of the Milky Way interstellar medium (ISM) and ISM+halo. In addition, quasar sight lines of intermediate redshift galaxies with 6 < D < 25 kpc have an equivalent width <span class="hlt">distribution</span> similar to that of the Milky Way halo, implying that beyond ∼6 kpc, quasar sight lines are likely probing halo <span class="hlt">gas</span> and not the ISM. As inferred by the Milky Way and our new data, the <span class="hlt">gas</span> profiles of galaxies can be fit by a single log-linear W{sub r} (2796)-D relation out to large scales across a variety of <span class="hlt">gas</span>-phase conditions and is maintained through the halo/extra-planar/ISM interfaces, which is remarkable considering their kinematic complexity. These low-redshift, small impact parameter absorption systems are the first steps to bridge the gap between quasar absorption-line studies and H I observations of the circumgalactic medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25901760','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25901760"><span>Occurrence and Spatial <span class="hlt">Distribution</span> of Microplastics in River Shore Sediments of the Rhine-<span class="hlt">Main</span> Area in Germany.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klein, Sascha; Worch, Eckhard; Knepper, Thomas P</p> <p>2015-05-19</p> <p>Plastic debris is one of the most significant organic pollutants in the aquatic environment. Because of properties such as buoyancy and extreme durability, synthetic polymers are present in rivers, lakes, and oceans and accumulate in sediments all over the world. However, freshwater sediments have attracted less attention than the investigation of sediments in marine ecosystems. For this reason, river shore sediments of the rivers Rhine and <span class="hlt">Main</span> in the Rhine-<span class="hlt">Main</span> area in Germany were analyzed. The sample locations comprised shore sediment of a large European river (Rhine) and a river characterized by industrial influence (<span class="hlt">Main</span>) in areas with varying population sizes as well as sites in proximity to nature reserves. All sediments analyzed contained microplastic particles (<5 mm) with mass fractions of up to 1 g kg⁻¹ or 4000 particles kg⁻¹. Analysis of the plastics by infrared spectroscopy showed a large abundance of polyethylene, polypropylene, and polystyrene, which covered more than 75% of all polymer types identified in the sediment. Short distance transport of plastic particles from the tributary to the <span class="hlt">main</span> stream could be confirmed by the identification of pellets, which were separated from shore sediment samples of both rivers. This systematic study shows the emerging pollution of inland river sediments with microplastics and, as a consequence thereof, underlines the importance of rivers as vectors of transport of microplastics into the ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20668402','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20668402"><span>Can a fermentation <span class="hlt">gas</span> <span class="hlt">mainly</span> produced by rumen Isotrichidae ciliates be a potential source of biohydrogen and a fuel for a chemical fuel cell?</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Piela, Piotr; Michałowski, Tadeusz; Miltko, Renata; Szewczyk, Krzysztof; Sikora, Radosław; Grzesiuk, Elzbieta; Sikora, Anna</p> <p>2010-07-01</p> <p>Bacteria, fungi and protozoa inhabiting the rumen, the largest chamber of the ruminants' stomach, release large quantities of hydrogen during the fermentation of carbohydrates. The hydrogen is used by coexisting methanogens to produce methane in energy-yielding processes. This work shows, for the first time, a fundamental possibility of using a hydrogen-rich fermentation <span class="hlt">gas</span> produced by selected rumen ciliates to feed a low-temperature hydrogen fuel cell. A biohydrogen fuel cell (BHFC) was constructed consisting of (i) a bioreactor, in which a hydrogen-rich <span class="hlt">gas</span> was produced from glucose by rumen ciliates, <span class="hlt">mainly</span> of the Isotrichidae family, deprived of intra- and extracellular bacteria, methanogens, and fungi, and (ii) a chemical fuel cell of the polymer-electrolyte type (PEFC). The fuel cell was used as a tester of the technical applicability of the fermentation <span class="hlt">gas</span> produced by the rumen ciliates for power generation. The average estimated hydrogen yield was ca. 1.15 mol H2 per mol of fermented glucose. The BHFC performance was equal to the performance of the PEFC running on pure hydrogen. No fuel cell poisoning effects were detected. A maximum power density of 1.66 kW/m2 (PEFC geometric area) was obtained at room temperature. The maximum volumetric power density was 128 W/m3 but the coulombic efficiency was only ca. 3.8%. The configuration of the bioreactor limited the continuous operation time of this BHFC to ca. 14 hours.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title49-vol3/pdf/CFR-2012-title49-vol3-sec192-197.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title49-vol3/pdf/CFR-2012-title49-vol3-sec192-197.pdf"><span>49 CFR 192.197 - Control of the pressure of <span class="hlt">gas</span> delivered from high-pressure <span class="hlt">distribution</span> systems.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 49 Transportation 3 2012-10-01 2012-10-01 false Control of the pressure of <span class="hlt">gas</span> delivered from high... STANDARDS Design of Pipeline Components § 192.197 Control of the pressure of <span class="hlt">gas</span> delivered from high... external static or control lines. (b) If the maximum actual operating pressure of the <span class="hlt">distribution</span>...</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009CoTPh..51..259C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009CoTPh..51..259C"><span>Spatial Density <span class="hlt">Distributions</span> and Correlations in a Quasi-one-Dimensional Polydisperse Granular <span class="hlt">Gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Zhi-Yuan; Zhang, Duan-Ming</p> <p>2009-02-01</p> <p>By Monte Carlo simulations, the effect of the dispersion of particle size <span class="hlt">distribution</span> on the spatial density <span class="hlt">distributions</span> and correlations of a quasi one-dimensional polydisperse granular <span class="hlt">gas</span> with fractal size <span class="hlt">distribution</span> is investigated in the same inelasticity. The dispersive degree of the particle size <span class="hlt">distribution</span> can be measured by a fractal dimension df, and the smooth particles are constrained to move along a circle of length L, colliding inelastically with each other and thermalized by a viscosity heat bath. When the typical relaxation time τ of the driving Brownian process is longer than the mean collision time τc, the system can reach a nonequilibrium steady state. The average energy of the system decays exponentially with time towards a stable asymptotic value, and the energy relaxation time τB to the steady state becomes shorter with increasing values of df. In the steady state, the spatial density <span class="hlt">distribution</span> becomes more clusterized as df increases, which can be quantitatively characterized by statistical entropy of the system. Furthermore, the spatial correlation functions of density and velocities are found to be a power-law form for small separation distance of particles, and both of the correlations become stronger with the increase of df. Also, the density clusterization is explained from the correlations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/920150','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/920150"><span>On the work <span class="hlt">distribution</span> for the adiabatic compression of a diluteclassical <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Crooks, Gavin E.; Jarzynski, Christopher</p> <p>2006-02-23</p> <p>We consider the adiabatic and quasi-static compression of adilute classical <span class="hlt">gas</span>, confined in a piston and initially equilibratedwith a heat bath. We find that the work performed during this process isdescribed statistically by a gamma <span class="hlt">distribution</span>. We use this result toshow that the model satisfies the non-equilibrium work and fluctuationtheorems, but not the fluctation-dissipation relation. We discuss therare but dominant realizations that contribute most to the exponentialaverage of the work, and relate our results to potentially universal workdistributions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JQSRT.102..304C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JQSRT.102..304C"><span>Remote sensing of high temperature H2O CO2 CO mixture with a correlated k-<span class="hlt">distribution</span> fictitious <span class="hlt">gas</span> method and the single-mixture <span class="hlt">gas</span> assumption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caliot, C.; Le Maoult, Y.; El Hafi, M.; Flamant, G.</p> <p>2006-11-01</p> <p>Infrared spectra of high temperature H2O CO2 CO mixtures are calculated using narrow band models in order to simulate hot jet signature at long distance. The correlated k-<span class="hlt">distribution</span> with fictitious <span class="hlt">gas</span> (CKFG) approach generally gives accurate data in such situations (especially for long atmospheric paths) but results in long computation time in cases involving mixtures of gases. This time may be reduced if the mixture is treated as a single <span class="hlt">gas</span> (single-mixture <span class="hlt">gas</span> assumption, SMG). Thus the lines of the single-mixture <span class="hlt">gas</span> are assigned to the fictitious gases. In this study, the accuracy of two narrow band models is evaluated. The first narrow band model considers one single-mixture <span class="hlt">gas</span> and no fictitious <span class="hlt">gas</span> (CK-SMG) whereas the second model accounts for one single-mixture <span class="hlt">gas</span> and three fictitious gases (CKFG-SMG). Both narrow band models are compared with reference spectra calculated with a line-by-line (LBL) approach. As expected, the narrow band accuracy is improved by the fictitious <span class="hlt">gas</span> (FG) assumption particularly when long atmospheric paths are involved. Concerning the SMG assumption, it may lead to an underestimation of about 10% depending on the variation of the <span class="hlt">gas</span> mixture composition ratio. Nevertheless, in most of realistic situations the SMG assumption results in negligible errors and may be used for remote sensing of plume signature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MNRAS.464.2341C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MNRAS.464.2341C"><span>On the determination of the He abundance <span class="hlt">distribution</span> in globular clusters from the width of the <span class="hlt">main</span> sequence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cassisi, Santi; Salaris, Maurizio; Pietrinferni, Adriano; Hyder, David</p> <p>2017-01-01</p> <p>One crucial piece of information to study the origin of multiple stellar populations in globular clusters is the range of initial helium abundances ΔY amongst the sub-populations hosted by each cluster. These estimates are commonly obtained by measuring the width in colour of the unevolved <span class="hlt">main</span> sequence in an optical colour-magnitude diagram (CMD). The measured colour spread is then compared with predictions from theoretical stellar isochrones with varying initial He abundances to determine ΔY. The availability of UV/optical magnitudes, thanks to the Hubble Space Telescope UV Legacy Survey of Galactic GCs project, will allow the homogeneous determination of ΔY for a large Galactic globular cluster sample. From a theoretical point of view, accurate UV CMDs can efficiently disentangle the various sub-populations, and <span class="hlt">main</span> sequence colour differences in the ACS F606W - (F606W - F814W) diagram allow an estimate of ΔY. We demonstrate that from a theoretical perspective, the (F606W - F814W) colour is an extremely reliable He-abundance indicator. The derivative dY/d(F606W - F814W), computed at a fixed luminosity along the unevolved <span class="hlt">main</span> sequence, is largely insensitive to the physical assumptions made in stellar model computations, being more sensitive to the choice of the bolometric correction scale, and is only slightly dependent on the adopted set of stellar models. From a theoretical point of view, the (F606W - F814W) colour width of the cluster <span class="hlt">main</span> sequence is therefore a robust diagnostic of the ΔY range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.6419P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.6419P"><span>Global <span class="hlt">distribution</span> of <span class="hlt">gas</span> hydrates in marine sediments: application of a general transfer function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Piñero, Elena; Marquardt, Mathias; Hensen, Christian; Haeckel, Matthias</p> <p>2010-05-01</p> <p>Many of the recently published estimates of the global inventory of marine methane hydrate are based on simplified diagenetic models, which were run for each grid point of a homogeneous grid of the seafloor. Since this is a very complex and time-consuming method, which may also be limited by data availability, we invented a simple transfer function, which calculates the amount of <span class="hlt">gas</span> hydrates based on easily accessible data. The transfer function was derived from a large set of systematic runs of a numerical diagenetic model covering the wide range of environmental conditions that are typically met along the continental margins. An exhaustive parameter analysis established that the formation of <span class="hlt">gas</span> hydrates from biogenic methane production can be sufficiently described by the total organic carbon accumulation rate and the thickness of the <span class="hlt">gas</span> hydrate stability zone (Marquardt et al., submitted). The resulting transfer function was applied to available global datasets of 1x1-degree resolution in order to derive global estimates of the <span class="hlt">distribution</span> and total inventory of <span class="hlt">gas</span> hydrates. The global grids include the seafloor bathymetry, TOC input (Seiter et al., 2004), bottom water temperature, and geothermal gradient estimated from heat flow (Hamza et al., 2008). The global amount of <span class="hlt">gas</span> hydrate is predicted to be about 2400 Gt of C and is in good agreement with previously published results (e.g. Archer et al., 2009). So far, our calculations do not consider any thermogenic methane, but only microbially produced and hence, represent only a minimum estimate of the <span class="hlt">gas</span> hydrate budget. References: Archer et al., 2009. Ocean methane hydrates as a slow tipping point in the global carbon cycle. PNAS 106 (49), 20596-20601. Hamza et al., 2008. Spherical harmonic analysis of the Earth's conductive heat flow. Intern. J. Earth Sci., 97, 205-226 Marquardt et al. Submitted. Estimation of <span class="hlt">gas</span> hydrate inventories in marine sediments: derivation and testing of a transfer function</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5017353','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5017353"><span>A Robust <span class="hlt">Distributed</span> Multipoint Fiber Optic <span class="hlt">Gas</span> Sensor System Based on AGC Amplifier Structure</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhu, Cunguang; Wang, Rende; Tao, Xuechen; Wang, Guangwei; Wang, Pengpeng</p> <p>2016-01-01</p> <p>A harsh environment-oriented <span class="hlt">distributed</span> multipoint fiber optic <span class="hlt">gas</span> sensor system realized by automatic gain control (AGC) technology is proposed. To improve the photoelectric signal reliability, the electronic variable gain can be modified in real time by an AGC closed-loop feedback structure to compensate for optical transmission loss which is caused by the fiber bend loss or other reasons. The deviation of the system based on AGC structure is below 4.02% when photoelectric signal decays due to fiber bending loss for bending radius of 5 mm, which is 20 times lower than the ordinary differential system. In addition, the AGC circuit with the same electric parameters can keep the baseline intensity of signals in different channels of the <span class="hlt">distributed</span> multipoint sensor system at the same level. This avoids repetitive calibrations and streamlines the installation process. PMID:27483267</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930091937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930091937"><span>Effects of temperature <span class="hlt">distribution</span> and elastic properties of materials on <span class="hlt">gas</span>-turbine-disk stresses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Holms, Arthur G; Faldetta, Richard D</p> <p>1947-01-01</p> <p>Calculations were made to determine the influence of changes in temperature <span class="hlt">distribution</span> and in elastic material properties on calculated elastic stresses for a typical <span class="hlt">gas</span>-turbine disk. Severe temperature gradients caused thermal stresses of sufficient magnitude to reduce the operating safety of the disk. Small temperature gradients were found to be desirable because they produced thermal stresses that subtracted from the centrifugal stresses in the region of the rim. The thermal gradients produced a tendency for a severe stress condition to exist near the rim but this stress condition could be shifted away from the region of blade attachment by altering the temperature <span class="hlt">distribution</span>. The investigation of elastic material properties showed that centrifugal stresses are slightly affected by changes in modulus of elasticity, but that thermal stresses are approximately proportional to modulus of elasticity and to coefficient of thermal expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16907070','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16907070"><span>Generic features of the wealth <span class="hlt">distribution</span> in ideal-<span class="hlt">gas</span>-like markets.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mohanty, P K</p> <p>2006-07-01</p> <p>We provide an exact solution to the ideal-<span class="hlt">gas</span>-like models studied in econophysics to understand the microscopic origin of Pareto law. In these classes of models the key ingredient necessary for having a self-organized scale-free steady-state <span class="hlt">distribution</span> is the trading or collision rule where agents or particles save a definite fraction of their wealth or energy and invest the rest for trading. Using a Gibbs ensemble approach we could obtain the exact <span class="hlt">distribution</span> of wealth in this model. Moreover we show that in this model (a) good savers are always rich and (b) every agent poor or rich invests the same amount for trading. Nonlinear trading rules could alter the generic scenario observed here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70174967','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70174967"><span>Characterization of <span class="hlt">gas</span> hydrate <span class="hlt">distribution</span> using conventional 3D seismic data in the Pearl River Mouth Basin, South China Sea</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wang, Xiujuan; Qiang, Jin; Collett, Timothy S.; Shi, Hesheng; Yang, Shengxiong; Yan, Chengzhi; Li, Yuanping; Wang, Zhenzhen; Chen, Duanxin</p> <p>2016-01-01</p> <p>A new 3D seismic reflection data volume acquired in 2012 has allowed for the detailed mapping and characterization of <span class="hlt">gas</span> hydrate <span class="hlt">distribution</span> in the Pearl River Mouth Basin in the South China Sea. Previous studies of core and logging data showed that <span class="hlt">gas</span> hydrate occurrence at high concentrations is controlled by the presence of relatively coarse-grained sediment and the upward migration of thermogenic <span class="hlt">gas</span> from the deeper sediment section into the overlying <span class="hlt">gas</span> hydrate stability zone (BGHSZ); however, the spatial <span class="hlt">distribution</span> of the <span class="hlt">gas</span> hydrate remains poorly defined. We used a constrained sparse spike inversion technique to generate acoustic-impedance images of the hydrate-bearing sedimentary section from the newly acquired 3D seismic data volume. High-amplitude reflections just above the bottom-simulating reflectors (BSRs) were interpreted to be associated with the accumulation of <span class="hlt">gas</span> hydrate with elevated saturations. Enhanced seismic reflections below the BSRs were interpreted to indicate the presence of free <span class="hlt">gas</span>. The base of the BGHSZ was established using the occurrence of BSRs. In areas absent of well-developed BSRs, the BGHSZ was calculated from a model using the inverted P-wave velocity and subsurface temperature data. Seismic attributes were also extracted along the BGHSZ that indicate variations reservoir properties and inferred hydrocarbon accumulations at each site. <span class="hlt">Gas</span> hydrate saturations estimated from the inversion of acoustic impedance of conventional 3D seismic data, along with well-log-derived rock-physics models were also used to estimate <span class="hlt">gas</span> hydrate saturations. Our analysis determined that the <span class="hlt">gas</span> hydrate petroleum system varies significantly across the Pearl River Mouth Basin and that variability in sedimentary properties as a product of depositional processes and the upward migration of <span class="hlt">gas</span> from deeper thermogenic sources control the <span class="hlt">distribution</span> of <span class="hlt">gas</span> hydrates in this basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017PhPl...24b3508F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017PhPl...24b3508F"><span>Effect of <span class="hlt">distribution</span> of electric field on low-pressure <span class="hlt">gas</span> breakdown</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, Yangyang; Yang, Shuo; Zou, Xiaobing; Luo, Haiyun; Wang, Xinxin</p> <p>2017-02-01</p> <p>A low-pressure <span class="hlt">gas</span> breakdown in a gap of the non-uniform electric field between two plane-parallel electrodes was studied. The experiments were specially designed to neatly separate the effect of a centered dielectric tube in between the electrodes on the breakdown from the effect of the electric field <span class="hlt">distribution</span> determined by the electrode geometry on the breakdown. For a given electrode radius and an interelectrode distance, when the diameter of the centered dielectric tube in between the electrodes is smaller, the breakdown voltage is lower, which is most possibly as a result of the flashover more easily happening along the surface of the smaller tube on which the more charged particles are accumulated. When the dielectric tube in between the electrodes is removed, the breakdown voltage depends not only on the product of <span class="hlt">gas</span> pressure and gap length but also on the aspect ratio of the <span class="hlt">gas</span> gap, i.e., Ub = f(pd, d/r). Furthermore, Ub = f(pd, d/r) was proved to automatically fulfill two necessary conditions for the similar discharges in the non-uniform electric field, which implies that Ub = f(pd, d/r) is an expression of the similarity theorem in the breakdown of a gap between two plane-parallel electrodes and confirms Townsend's prediction that the general similarity theorem can be applied equally to the breakdowns in non-uniform fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27690048','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27690048"><span>Planar Indium Tin Oxide Heater for Improved Thermal <span class="hlt">Distribution</span> for Metal Oxide Micromachined <span class="hlt">Gas</span> Sensors.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Çakır, M Cihan; Çalışkan, Deniz; Bütün, Bayram; Özbay, Ekmel</p> <p>2016-09-29</p> <p>Metal oxide <span class="hlt">gas</span> sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide <span class="hlt">gas</span> sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide <span class="hlt">gas</span> sensor integrated with a simple square planar indium tin oxide (ITO) heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption-dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature <span class="hlt">distribution</span> uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5087400','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5087400"><span>Planar Indium Tin Oxide Heater for Improved Thermal <span class="hlt">Distribution</span> for Metal Oxide Micromachined <span class="hlt">Gas</span> Sensors</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Çakır, M. Cihan; Çalışkan, Deniz; Bütün, Bayram; Özbay, Ekmel</p> <p>2016-01-01</p> <p>Metal oxide <span class="hlt">gas</span> sensors with integrated micro-hotplate structures are widely used in the industry and they are still being investigated and developed. Metal oxide <span class="hlt">gas</span> sensors have the advantage of being sensitive to a wide range of organic and inorganic volatile compounds, although they lack selectivity. To introduce selectivity, the operating temperature of a single sensor is swept, and the measurements are fed to a discriminating algorithm. The efficiency of those data processing methods strongly depends on temperature uniformity across the active area of the sensor. To achieve this, hot plate structures with complex resistor geometries have been designed and additional heat-spreading structures have been introduced. In this work we designed and fabricated a metal oxide <span class="hlt">gas</span> sensor integrated with a simple square planar indium tin oxide (ITO) heating element, by using conventional micromachining and thin-film deposition techniques. Power consumption–dependent surface temperature measurements were performed. A 420 °C working temperature was achieved at 120 mW power consumption. Temperature <span class="hlt">distribution</span> uniformity was measured and a 17 °C difference between the hottest and the coldest points of the sensor at an operating temperature of 290 °C was achieved. Transient heat-up and cool-down cycle durations are measured as 40 ms and 20 ms, respectively. PMID:27690048</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10104335','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10104335"><span>Review of performance-based ratemaking plans for US <span class="hlt">gas</span> <span class="hlt">distribution</span> companies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Comnes, G.A.</p> <p>1994-11-01</p> <p>Performance-Based Ratemaking (PBR) is receiving increasing attention by energy utilities and their regulators. PBR is the industry term for forms of regulation that increase financial incentive for performance relative to traditional cost-of-service/rate-of-return (COS/ROR) regulation. In this report, PBR plans filed by US <span class="hlt">gas</span> local <span class="hlt">distribution</span> companies (LDCs) are described and reviewed. The rationale behind energy utility PBR is presented and discussed. Using nine plans that have been proposed by eight LDCs as a basis, a framework (typology) to facilitate understanding of <span class="hlt">gas</span> utility PBR is presented. Plans are categorized according to the range of services covered by the PBR mechanism and the scope of the mechanism`s cost coverage within a service category. Pivotal design issues are identified and, based on the sample of plans, observations are made. Design issues covered include the length of time that the PBR is in effect (term); the relationship between PBR plans and status quo ratemaking; methods for formulating cost or rate indices, earnings sharing mechanisms, and service quality indices; and compatibility with <span class="hlt">gas</span> utility DSM programs. The report summarizes observations that may be considered supportive of the rationale behind PBR. PBR is, however, not clearly superior to traditional regulation and few PBRs that are broad in scope have been adopted long enough to allow for a empirical analysis. Thus, the report concludes by identifying and describing commonly-cited pitfalls of PBR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70018545','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70018545"><span>The nature, <span class="hlt">distribution</span>, and origin of <span class="hlt">gas</span> hydrate in the Chile Triple Junction region</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Brown, K.M.; Bangs, N.L.; Froelich, P.N.; Kvenvolden, K.A.</p> <p>1996-01-01</p> <p>A bottom simulating reflector (BSR) is regionally <span class="hlt">distributed</span> throughout much of the Chile Triple Junction (CTJ) region. Downhole temperature and logging data collected during Ocean Drilling Program (ODP) Leg 141 suggest that the seismic BSR is generated by low seismic velocities associated with the presence of a few percent free <span class="hlt">gas</span> in a ??? 10 m thick zone just beneath the hydrate-bearing zone. The data also indicate that the temperature and pressure at the BSR best corresponds to the seawater/methane hydrate stability field. The origin of the large amounts of methane required to generate the hydrates is, however, problematic. Low total organic carbon contents and low alkalinities argue against significant in situ biogenic methanogenesis, but additional input from thermogenic sources also appears to be precluded. Increasing thermal gradients, associated with the approach of the spreading ridge system, may have caused the base of the hydrate stability field to migrate 300 m upwards in the sediments. We propose that the upward migration of the base of the stability field has concentrated originally widely dispersed hydrate patches into the more continuous hydrate body we see today. The methane can be concentrated if the <span class="hlt">gas</span> hydrates can form from dissolved methane, transported into the hydrate zone via diffusion or fluid advection. A strong gradient may exist in dissolved methane concentration across the BSR leading to the steady reabsorbtion of the free <span class="hlt">gas</span> zone during the upward migration of the BSR even in the absence of fluid advection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013hsa7.conf...13M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013hsa7.conf...13M"><span>Analysis of the spatial <span class="hlt">distribution</span> of stars, <span class="hlt">gas</span> and dust in nearby galaxies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muñoz-Mateos, J. C.</p> <p>2013-05-01</p> <p>I summarize the <span class="hlt">main</span> result of my thesis, which was awarded the Spanish Astronomical Society Award for the best thesis in Astronomy defended in 2010. This thesis was supervised by Armando Gil de Paz and Jaime Zamorano at Universidad Complutense de Madrid. In this work we quantified how the physical properties of stars, <span class="hlt">gas</span> and dust vary with radius in nearby galactic disks, and used that information to infer the past assembly and evolution of galaxies. To do so we made use of spatially-resolved multi-wavelength images of nearby galaxies, all the way from the far-UV to the far-IR and radio. By comparing extinction- corrected profiles in the UV, optical and IR with models of disk evolution, we concluded that the current stellar population gradients are consistent with an inside-out growth of disks of ˜ 25% since z ˜ 1. We also found that the dust-to-<span class="hlt">gas</span> ratio decreases with radius, and is tightly correlated with the local <span class="hlt">gas</span> metallicity, which is again consistent with an inside-out assembly of disks. We measured the fraction of the dust mass which is in the form of PAHs at different radii. The resulting trend agrees with certain models of dust evolution, in which the abundance of PAHs is primarily determined by a delayed injection of carbon into the ISM by AGB stars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AAS...22742407Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AAS...22742407Z"><span>Toward Measuring Galactic Dense Molecular <span class="hlt">Gas</span> Properties and 3D <span class="hlt">Distribution</span> with Hi-GAL</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zetterlund, Erika; Glenn, Jason; Maloney, Phil</p> <p>2016-01-01</p> <p>The Herschel Space Observatory's submillimeter dust continuum survey Hi-GAL provides a powerful new dataset for characterizing the structure of the dense interstellar medium of the Milky Way. Hi-GAL observed a 2° wide strip covering the entire 360° of the Galactic plane in broad bands centered at 70, 160, 250, 350, and 500 μm, with angular resolution ranging from 10 to 40 arcseconds. We are adapting a molecular cloud clump-finding algorithm and a distance probability density function distance-determination method developed for the Bolocam Galactic Plane Survey (BGPS) to the Hi-GAL data. Using these methods we expect to generate a database of 105 cloud clumps, derive distance information for roughly half the clumps, and derive precise distances for approximately 20% of them. With five-color photometry and distances, we will measure the cloud clump properties, such as luminosities, physical sizes, and masses, and construct a three-dimensional map of the Milky Way's dense molecular <span class="hlt">gas</span> <span class="hlt">distribution</span>.The cloud clump properties and the dense <span class="hlt">gas</span> <span class="hlt">distribution</span> will provide critical ground truths for comparison to theoretical models of molecular cloud structure formation and galaxy evolution models that seek to emulate spiral galaxies. For example, such models cannot resolve star formation and use prescriptive recipes, such as converting a fixed fraction of interstellar <span class="hlt">gas</span> to stars at a specified interstellar medium density threshold. The models should be compared to observed dense molecular <span class="hlt">gas</span> properties and galactic <span class="hlt">distributions</span>.As a pilot survey to refine the clump-finding and distance measurement algorithms developed for BGPS, we have identified molecular cloud clumps in six 2° × 2° patches of the Galactic plane, including one in the inner Galaxy along the line of sight through the Molecular Ring and the termination of the Galactic bar and one toward the outer Galaxy. Distances have been derived for the inner Galaxy clumps and compared to Bolocam Galactic Plane</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/6353912','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/6353912"><span>An historical prospective study of mortality within a cohort of <span class="hlt">gas</span> <span class="hlt">distribution</span> workers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liveright, T; Stanbury, M</p> <p>1983-01-01</p> <p>An historical prospective study of mortality within a cohort of 1,410 <span class="hlt">gas</span> <span class="hlt">distribution</span> workers was conducted. This cohort was followed for ten years (1971-1980) and data on 118 deaths were obtained. Five-year (1973-1977) averages of both St. Louis and United States age-specific mortality figures were used to create "expected" mortality rates for comparison with the observed deaths in the cohort. Analyses of the cohort were done according to: 1) person-years contributed during the study period (the "age-attained" method) and 2) the number of years from commencement of work in the company until the end of the study period (1980) or death (the "latency" methods of analysis, Standardized Mortality Ratios (SMRs) were calculated for all causes of death, all malignant neoplasms, and for cardiovascular disease and malignant neoplasms of the respiratory and digestive systems. In no case was the SMR found to be beyond the range of what would be expected in the "standard" populations. While the present study does not contradict the negative findings of the one previous investigation of mortality of <span class="hlt">gas</span> <span class="hlt">distribution</span> workers, the limitations of small cohort size, reliance on death certificates and non-industrial comparison populations make any conclusions at best provisional.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22107078','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22107078"><span>Methodology to model the energy and greenhouse <span class="hlt">gas</span> emissions of electronic software <span class="hlt">distributions</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Williams, Daniel R; Tang, Yinshan</p> <p>2012-01-17</p> <p>A new electronic software <span class="hlt">distribution</span> (ESD) life cycle analysis (LCA) methodology and model structure were constructed to calculate energy consumption and greenhouse <span class="hlt">gas</span> (GHG) emissions. In order to counteract the use of high level, top-down modeling efforts, and to increase result accuracy, a focus upon device details and data routes was taken. In order to compare ESD to a relevant physical <span class="hlt">distribution</span> alternative, physical model boundaries and variables were described. The methodology was compiled from the analysis and operational data of a major online store which provides ESD and physical <span class="hlt">distribution</span> options. The ESD method included the calculation of power consumption of data center server and networking devices. An in-depth method to calculate server efficiency and utilization was also included to account for virtualization and server efficiency features. Internet transfer power consumption was analyzed taking into account the number of data hops and networking devices used. The power consumed by online browsing and downloading was also factored into the model. The embedded CO(2)e of server and networking devices was proportioned to each ESD process. Three U.K.-based ESD scenarios were analyzed using the model which revealed potential CO(2)e savings of 83% when ESD was used over physical <span class="hlt">distribution</span>. Results also highlighted the importance of server efficiency and utilization methods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990DSRA...37..381C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990DSRA...37..381C"><span><span class="hlt">Distribution</span> of rose bengal stained deep-sea benthic foraminifera from the Nova Scotian continental margin and Gulf of <span class="hlt">Maine</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Corliss, Bruce H.; Emerson, Steven</p> <p>1990-03-01</p> <p>Analysis of Rose Bengal stained benthic foraminifera in six boxcores taken from the Nova Scotian margin and Gulf of <span class="hlt">Maine</span> reveals that foraminifera are vertically stratified within surficial sediments raised from 200 to 3000 m water depth. The consistent presence of infaunal taxa within the sediments demonstrates that these tolerant of a range of low-oxygen conditions as determined by pore-water manganese profiles. The habitat depth of foraminiferal populations, defined as the depth within which 95% of the fauna is found in a subcore, varies between the stations. A shallow habitat depth of 3 cm exists in shallow water (a 202 m core) in the Gulf of <span class="hlt">Maine</span>. The habitat depth gradually increases on the continental slope with increasing water depth, reaching 11-13 cm in cores at 2225 and 3000 m, and then shoals to 4 cm in a core taken from 4800 m water depth. We suggest that the habitat pattern is related to the flux of organic carbon to the seafloor. At shallow depths, relatively high organic carbon flux results in a shallow oxic layer. The inferred oxic layer gradually increases on the continental slope and rise with increasing water depth, due to decreased organic carbon flux to the sediment-water interface. Carbon fluxes in the deep ocean are so low that pore waters are oxic and the organic carbon content is low, creating a food-limiting environment best suited to epifaunal taxa and reflected in a shallow habitat depth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/140914','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/140914"><span>Model documentation: Natural <span class="hlt">Gas</span> Transmission and <span class="hlt">Distribution</span> Model of the National Energy Modeling System; Volume 1</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1994-02-24</p> <p>The Natural <span class="hlt">Gas</span> Transmission and <span class="hlt">Distribution</span> Model (NGTDM) is a component of the National Energy Modeling System (NEMS) used to represent the domestic natural <span class="hlt">gas</span> transmission and <span class="hlt">distribution</span> system. NEMS is the third in a series of computer-based, midterm energy modeling systems used since 1974 by the Energy Information Administration (EIA) and its predecessor, the Federal Energy Administration, to analyze domestic energy-economy markets and develop projections. This report documents the archived version of NGTDM that was used to produce the natural <span class="hlt">gas</span> forecasts used in support of the Annual Energy Outlook 1994, DOE/EIA-0383(94). The purpose of this report is to provide a reference document for model analysts, users, and the public that defines the objectives of the model, describes its basic design, provides detail on the methodology employed, and describes the model inputs, outputs, and key assumptions. It is intended to fulfill the legal obligation of the EIA to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). This report represents Volume 1 of a two-volume set. (Volume 2 will report on model performance, detailing convergence criteria and properties, results of sensitivity testing, comparison of model outputs with the literature and/or other model results, and major unresolved issues.) Subsequent chapters of this report provide: (1) an overview of the NGTDM (Chapter 2); (2) a description of the interface between the National Energy Modeling System (NEMS) and the NGTDM (Chapter 3); (3) an overview of the solution methodology of the NGTDM (Chapter 4); (4) the solution methodology for the Annual Flow Module (Chapter 5); (5) the solution methodology for the Distributor Tariff Module (Chapter 6); (6) the solution methodology for the Capacity Expansion Module (Chapter 7); (7) the solution methodology for the Pipeline Tariff Module (Chapter 8); and (8) a description of model assumptions, inputs, and outputs (Chapter 9).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21172694','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21172694"><span>Impact of Intrafractional Bowel <span class="hlt">Gas</span> Movement on Carbon Ion Beam Dose <span class="hlt">Distribution</span> in Pancreatic Radiotherapy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kumagai, Motoki; Hara, Ryusuke; Mori, Shinichiro Yanagi, Takeshi; Asakura, Hiroshi; Kishimoto, Riwa; Kato, Hirotoshi; Yamada, Shigeru; Kandatsu, Susumu; Kamada, Tadashi</p> <p>2009-03-15</p> <p>Purpose: To assess carbon ion beam dose variation due to bowel <span class="hlt">gas</span> movement in pancreatic radiotherapy. Methods and Materials: Ten pancreatic cancer inpatients were subject to diagnostic contrast-enhanced dynamic helical CT examination under breath-holding conditions, which included multiple-phase dynamic CT with arterial, venous, and delayed phases. The arterial-venous phase and arterial-delayed phase intervals were 35 and 145 s, respectively. A compensating bolus was designed to cover the target obtained at the arterial phase. Carbon ion dose <span class="hlt">distribution</span> was calculated by applying the bolus to the CT data sets at the other two phases. Results: Dose conformation to the clinical target volume was degraded by beam overshoot/undershoot due to bowel <span class="hlt">gas</span> movement. The D95 for clinical target volume was degraded from 98.2% (range, 98.0-99.1%) of the prescribed dose to 94.7% (range, 88.0-99.0%) at 145 s. Excessive dosing to normal tissues varied among tissues and was, for example, 12.2 GyE/13.1 GyE (0 s/145 s) for the cord and 38.8 GyE/39.8 GyE (0 s/145 s) for the duodenum. The magnitude of beam overshoot/undershoot was particularly exacerbated from the anterior and left directions. Conclusions: Bowel <span class="hlt">gas</span> movement causes dosimetric variation to the target during treatment for radiotherapy. The effect of bowel <span class="hlt">gas</span> movement varies with beam angle, with greatest influence on the anterior-posterior and left-right beams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26240191','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26240191"><span>Determination of carbon number <span class="hlt">distributions</span> of complex phthalates by <span class="hlt">gas</span> chromatography-mass spectrometry with ammonia chemical ionization.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Di Sanzo, Frank P; Lim, Peniel J; Han, Wenning W</p> <p>2015-01-01</p> <p>An assay method for phthalate esters with a complex mixture of isomer of varying carbon numbers, such as di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP), using <span class="hlt">gas</span> chromatography-mass spectrometry (GC-MS) positive chemical ionization (PCI) with 5% ammonia in methane is described. GC-MS-PCI-NH3, unlike GC-MS electron ionization (EI) (GC-MS-EI) that produces generally m/z 149 ion as the <span class="hlt">main</span> base peak and low intensity M(+) peaks, produces higher intensity (M + 1) ions that allow the determination of total (R + R') carbon number <span class="hlt">distributions</span> based on the various R and R' alkyl groups of the di-esters moiety. The technique allows distinguishing among the various commercial DINP and DIDP plasticizers. The carbon number <span class="hlt">distributions</span> are determined in the acceptable range of <0.1 mole percent to >85 mole percent (m/m). Several examples of analysis made on commercial DINP and DIDP are presented. The use of only 5% instead of 100% ammonia simplifies use of GC-MS-PCI-NH3 but still produces sufficient M + 1 ion intensities that are appropriate for the assay. In addition, use of low concentrations of ammonia mitigates potential safety aspects related to use of ammonia and provides less corrosion for the instrument hardware.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22518775','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22518775"><span>A HIGHER EFFICIENCY OF CONVERTING <span class="hlt">GAS</span> TO STARS PUSHES GALAXIES AT z ∼ 1.6 WELL ABOVE THE STAR-FORMING <span class="hlt">MAIN</span> SEQUENCE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Silverman, J. D.; Rujopakarn, W.; Daddi, E.; Liu, D.; Sargent, M.; Renzini, A.; Feruglio, C.; Kashino, D.; Sanders, D.; Kartaltepe, J.; Nagao, T.; Arimoto, N.; Berta, S.; Lutz, D.; Béthermin, M.; Koekemoer, A.; and others</p> <p>2015-10-20</p> <p>Local starbursts have a higher efficiency of converting <span class="hlt">gas</span> into stars, as compared to typical star-forming galaxies at a given stellar mass, possibly indicative of different modes of star formation. With the peak epoch of galaxy formation occurring at z > 1, it remains to be established whether such an efficient mode of star formation is occurring at high redshift. To address this issue, we measure the molecular <span class="hlt">gas</span> content of seven high-redshift (z ∼ 1.6) starburst galaxies with the Atacama Large Millimeter/submillimeter Array and IRAM/Plateau de Bure Interferometer. Our targets are selected from the sample of Herschel far-infrared-detected galaxies having star formation rates (∼300–800 M{sub ⊙} yr{sup −1}) elevated (≳4×) above the star-forming <span class="hlt">main</span> sequence (MS) and included in the FMOS-COSMOS near-infrared spectroscopic survey of star-forming galaxies at z ∼ 1.6 with Subaru. We detect CO emission in all cases at high levels of significance, indicative of high <span class="hlt">gas</span> fractions (∼30%–50%). Even more compelling, we firmly establish with a clean and systematic selection that starbursts, identified as MS outliers, at high redshift generally have a lower ratio of CO to total infrared luminosity as compared to typical MS star-forming galaxies, although with a smaller offset than expected based on past studies of local starbursts. We put forward a hypothesis that there exists a continuous increase in star formation efficiency with elevation from the MS with galaxy mergers as a possible physical driver. Along with a heightened star formation efficiency, our high-redshift sample is similar in other respects to local starbursts, such as being metal rich and having a higher ionization state of the interstellar medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT........44N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT........44N"><span>Characterizing the accumulation and <span class="hlt">distribution</span> of <span class="hlt">gas</span> hydrate in marine sediments using numerical models and seismic data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nimblett, Jillian Nicole</p> <p></p> <p>Despite the increasing availability of geophysical, geochemical, geotechnical, and biological data that characterize in situ properties of <span class="hlt">gas</span> hydrate reservoirs, the fundamental physical processes associated with <span class="hlt">gas</span> hydrate formation, accumulation, <span class="hlt">distribution</span> and dissociation in porous marine sediments remain poorly understood. This study focuses on the spatial and temporal accumulation of <span class="hlt">gas</span> hydrate in marine sediments through (1) a numerical model that explores the impact of hydraulic parameters on permeability evolution during hydrate formation; and (2) tomographic analysis of multichannel seismic data that constrain the local concentration of <span class="hlt">gas</span> hydrate. The results constrain the hydraulic parameters pertinent to the hydrodynamics of <span class="hlt">gas</span> hydrate reservoirs and provide insight about the physical and elastic properties of <span class="hlt">gas</span> hydrate bearing sediments relevant for estimating hydrate concentration in porous assemblages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25421110','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25421110"><span><span class="hlt">Distribution</span> of enantiomers of methadone and its <span class="hlt">main</span> metabolite EDDP in human tissues and blood of postmortem cases.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Holm, Karen Marie Dollerup; Linnet, Kristian</p> <p>2015-01-01</p> <p>Knowledge concerning the <span class="hlt">distribution</span> of methadone in postmortem human tissue and the effect of postmortem redistribution on methadone is today limited making the choice of a suitable substitute for femoral blood difficult when this is not available. Cardiac blood, femoral blood, muscle, and brain tissue concentrations of the enantiomers of methadone and its metabolite 2-ethyl-1,5-dimethyl-3,3-diphenylpyrrolinium were recorded for 155 postmortem cases. Brain and muscle tissue concentrations exceeded the femoral blood concentrations with a median fold of 2.3 and 1.6, respectively, but both had a better correlation than cardiac blood to femoral blood concentrations. The Kruskal-Wallis test showed a significant dependency on time and body mass index for some of the matrix ratios over femoral blood. We conclude brain or muscle tissue may constitute a better alternative for measurement of methadone than cardiac blood for situations in which femoral blood is not available, despite concentrations in both matrices being systematically higher.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CSR...101..109A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CSR...101..109A"><span>PAH assessment in the <span class="hlt">main</span> Brazilian offshore oil and <span class="hlt">gas</span> production area using semi-permeable membrane devices (SPMD) and transplanted bivalves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>André Lourenço, Rafael; Francisco de Oliveira, Fábio; Haddad Nudi, Adriana; Rebello Wagener, Ângela de Luca; Guadalupe Meniconi, Maria de Fátima; Francioni, Eleine</p> <p>2015-06-01</p> <p>The Campos Basin is Brazil's <span class="hlt">main</span> oil and <span class="hlt">gas</span> production area. In 2013, more than 50 million cubic meters of produced water (PW) was discharged into these offshore waters. Despite the large volumes of PW that are discharged in the Campos Basin each day, the ecological concern of the chemicals in the PW are not completely understood. Polycyclic aromatic hydrocarbons (PAH) are the most important contributors to the ecological hazards that are posed by discharged PW. This study aimed to evaluate the potential bioaccumulation of PAH using transplanted bivalves (Nodipecten nodosus) and semi-permeable membrane devices (SPMD). The study was conducted in two platforms that discharge PW (P19 and P40). Another platform that does not discharge PW (P25) was investigated for comparison with the obtained results. Time-integrated hydrocarbon concentrations using SPMD and transplanted bivalves were estimated from the seawater near the three platforms. The bioaccumulation of the PAH in the transplanted bivalves at platforms P19 and P40 were up to fivefold greater than the bioaccumulation of the PAH at platform P25. The lowest PAH concentrations were estimated for platform P25 (4.3-6.2 ng L-1), and the highest PAH concentrations were estimated for platform P19 (9.2-37.3 ng L-1). Both techniques were effective for determining the bioavailability of the PAH and for providing time-integrated hydrocarbon concentrations regarding oil and <span class="hlt">gas</span> production activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25826444','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25826444"><span>Direct measurements show decreasing methane emissions from natural <span class="hlt">gas</span> local <span class="hlt">distribution</span> systems in the United States.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lamb, Brian K; Edburg, Steven L; Ferrara, Thomas W; Howard, Touché; Harrison, Matthew R; Kolb, Charles E; Townsend-Small, Amy; Dyck, Wesley; Possolo, Antonio; Whetstone, James R</p> <p>2015-04-21</p> <p>Fugitive losses from natural <span class="hlt">gas</span> <span class="hlt">distribution</span> systems are a significant source of anthropogenic methane. Here, we report on a national sampling program to measure methane emissions from 13 urban <span class="hlt">distribution</span> systems across the U.S. Emission factors were derived from direct measurements at 230 underground pipeline leaks and 229 metering and regulating facilities using stratified random sampling. When these new emission factors are combined with estimates for customer meters, maintenance, and upsets, and current pipeline miles and numbers of facilities, the total estimate is 393 Gg/yr with a 95% upper confidence limit of 854 Gg/yr (0.10% to 0.22% of the methane delivered nationwide). This fraction includes emissions from city gates to the customer meter, but does not include other urban sources or those downstream of customer meters. The upper confidence limit accounts for the skewed <span class="hlt">distribution</span> of measurements, where a few large emitters accounted for most of the emissions. This emission estimate is 36% to 70% less than the 2011 EPA inventory, (based largely on 1990s emission data), and reflects significant upgrades at metering and regulating stations, improvements in leak detection and maintenance activities, as well as potential effects from differences in methodologies between the two studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780061632&hterms=gas+laws&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dgas%2Blaws','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780061632&hterms=gas+laws&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dgas%2Blaws"><span>The velocity <span class="hlt">distribution</span> of interstellar <span class="hlt">gas</span> observed in strong UV absorption lines</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cowie, L. L.; York, D. G.</p> <p>1978-01-01</p> <p>Observations of three strong interstellar UV absorption lines of N I (1199 A), N II (1083 A), and Si III (1206 A) in 47 stars of widely varying distance and a variety of spectral types are analyzed to obtain a velocity <span class="hlt">distribution</span> function for the interstellar <span class="hlt">gas</span>. A technique based on the maximum and minimum velocities observed along a line of sight is adopted because of heavy line blending, and results are discussed for both power-law and exponential <span class="hlt">distribution</span> functions. The expected <span class="hlt">distribution</span> of radiative-phase supernova remnants (SNRs) in the interstellar medium is calculated as a function of SNR birthrate and of the interstellar density in which they evolve. The results are combined with observed distance estimates, and it is shown that an interstellar density in excess of 0.1 per cu cm would be required to keep the SNRs sufficiently confined so that their cross sections are consistent with the observed number of components. The alternative possibility is considered that SNRs do not enter the radiative phase before escaping from the Galaxy or colliding with neighboring remnants.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017APS..APRE15001P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017APS..APRE15001P"><span><span class="hlt">Distributions</span> of <span class="hlt">Gas</span> and Galaxies from Galaxy Clusters to Larger Scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patej, Anna</p> <p>2017-01-01</p> <p>We address the <span class="hlt">distributions</span> of <span class="hlt">gas</span> and galaxies on three scales: the outskirts of galaxy clusters, the clustering of galaxies on large scales, and the extremes of the galaxy <span class="hlt">distribution</span>. In the outskirts of galaxy clusters, long-standing analytical models of structure formation and recent simulations predict the existence of density jumps in the <span class="hlt">gas</span> and dark matter profiles. We use these features to derive models for the <span class="hlt">gas</span> density profile, obtaining a simple fiducial model that is in agreement with both observations of cluster interiors and simulations of the outskirts. We next consider the galaxy density profiles of clusters; under the assumption that the galaxies in cluster outskirts follow similar collisionless dynamics as the dark matter, their <span class="hlt">distribution</span> should show a steep jump as well. We examine the profiles of a low-redshift sample of clusters and groups, finding evidence for the jump in some of these clusters. Moving to larger scales where massive galaxies of different types are expected to trace the same large-scale structure, we present a test of this prediction by measuring the clustering of red and blue galaxies at z 0.6, finding low stochasticity between the two populations. These results address a key source of systematic uncertainty - understanding how target populations of galaxies trace large-scale structure - in galaxy redshift surveys. Such surveys use baryon acoustic oscillations (BAO) as a cosmological probe, but are limited by the expense of obtaining sufficiently dense spectroscopy. With the intention of leveraging upcoming deep imaging data, we develop a new method of detecting the BAO in sparse spectroscopic samples via cross-correlation with a dense photometric catalog. This method will permit the extension of BAO measurements to higher redshifts than possible with the existing spectroscopy alone. Lastly, we connect galaxies near and far: the Local Group dwarfs and the high redshift galaxies observed by Hubble and Spitzer. We</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016A%26A...593A..37V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016A%26A...593A..37V"><span>Three-dimensional <span class="hlt">distribution</span> of hydrogen fluoride <span class="hlt">gas</span> toward NGC 6334 I and I(N)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van der Wiel, M. H. D.; Naylor, D. A.; Makiwa, G.; Satta, M.; Abergel, A.</p> <p>2016-09-01</p> <p>Context. The HF molecule has been proposed as a sensitive tracer of diffuse interstellar <span class="hlt">gas</span>, while at higher densities its abundance could be influenced heavily by freeze-out onto dust grains. Aims: We investigate the spatial <span class="hlt">distribution</span> of a collection of absorbing <span class="hlt">gas</span> clouds, some associated with the dense, massive star-forming core NGC 6334 I, and others with diffuse foreground clouds elsewhere along the line of sight. For the former category, we aim to study the dynamical properties of the clouds in order to assess their potential to feed the accreting protostellar cores. Methods: We use far-infrared spectral imaging from the Herschel SPIRE iFTS to construct a map of HF absorption at 243 μm in a 6'× 3.´5 region surrounding NGC 6334 I and I(N). Results: The combination of new mapping that is fully sampled spatially, but is spectrally unresolved with a previous, single-pointing, spectrally resolved HF signature yields a three-dimensional picture of absorbing <span class="hlt">gas</span> clouds in the direction of NGC 6334. Toward core I, the HF equivalent width matches that of the spectrally resolved observation. At angular separations ≳20'' from core I, the HF absorption becomes weaker, which is consistent with three of the seven components being associated with this dense star-forming envelope. Of the remaining four components, two disappear beyond ~1' distance from the NGC 6334 filament, suggesting that these clouds are spatially associated with the star-forming complex. Our data also implies a lack of <span class="hlt">gas</span>-phase HF in the envelope of core I(N). Using a simple description of adsorption onto and desorption from dust grain surfaces, we show that the overall lower temperature of the envelope of source I(N) is consistent with freeze-out of HF, while it remains in the <span class="hlt">gas</span> phase in source I. Conclusions: We use the HF molecule as a tracer of column density in diffuse <span class="hlt">gas</span> (nH ≈ 102-103cm-3), and find that it may uniquely trace a relatively low-density portion of the <span class="hlt">gas</span> reservoir</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.5316L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.5316L"><span>Global <span class="hlt">distribution</span> and <span class="hlt">Gas</span>-particle Partitioning of Polycyclic Aromatic Hydrocarbons - a Modelling Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lammel, G.; Sehili, A. M.</p> <p>2009-04-01</p> <p>Polycyclic aromatic hydrocarbons (PAHs) are emitted in all combustion processes. Some undergo re-volatilisation (multi-hopping). Little is known about degradation pathways and the processes determining <span class="hlt">gas</span>-particle partitioning (Lohmann & Lammel, 2004). <span class="hlt">Distribution</span> and fate have no been studied on the global scale so far (except for emissions in Europe and Russia; Sehili & Lammel, 2007). Anthracene (ANT), fluoranthene (FLT) and benzo[a]pyrene (BAP) have been studied under present-day climate and each 3 scenarios of atmospheric degradation and <span class="hlt">gas</span>-particle partitioning using an atmospheric general circulation model with embedded dynamic aerosol submodel, ECHAM-HAM (Stier et al., 2005) and re-volatilization from ground compartments (Semeena et al., 2006). 10 years were simulated with a time-step of 30 min and 2.8°x2.8° and 19 levels. Emissions were compiled based on emission factors in 27 major types of combustion technologies, scaled to 141 combustion technologies and their global <span class="hlt">distribution</span> as of 1996 (1°x1°) according to fuel type and the PM1 emission factor (Bond et al., 2004). The emissions were entried uniformly throughout the entire simulation time. Scenarios tested: AD = adsorption (according to the Junge empirical relationship; Pankow, 1987), OB = absorption in organic matter and adsorption to soot (Lohmann & Lammel, 2004) without and DP = with degradation in the atmospheric particulate phase. <span class="hlt">Gas</span>-particle partitioning in air influences drastically the atmospheric cycling, total environmental fate (e.g. compartmental <span class="hlt">distributions</span>) and the long-range transport potential (LRTP) of the substances studied. The LRTP is mostly regional. Comparison with observed levels indicate that degradation in the particulate phase must be slower than in the <span class="hlt">gas</span>-phase. Furthermore, the levels of semivolatile PAHs (ANT and FLT) at high latitudes and a European mid latitude site cannot be explained by partitioning due to adsorption alone, but point to both absorption into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ACP....16.1531D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ACP....16.1531D"><span>Pesticides in the atmosphere: a comparison of <span class="hlt">gas</span>-particle partitioning and particle size <span class="hlt">distribution</span> of legacy and current-use pesticides</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Degrendele, C.; Okonski, K.; Melymuk, L.; Landlová, L.; Kukučka, P.; Audy, O.; Kohoutek, J.; Čupr, P.; Klánová, J.</p> <p>2016-02-01</p> <p>This study presents a comparison of seasonal variation, <span class="hlt">gas</span>-particle partitioning, and particle-phase size <span class="hlt">distribution</span> of organochlorine pesticides (OCPs) and current-use pesticides (CUPs) in air. Two years (2012/2013) of weekly air samples were collected at a background site in the Czech Republic using a high-volume air sampler. To study the particle-phase size <span class="hlt">distribution</span>, air samples were also collected at an urban and rural site in the area of Brno, Czech Republic, using a cascade impactor separating atmospheric particulates according to six size fractions. Major differences were found in the atmospheric <span class="hlt">distribution</span> of OCPs and CUPs. The atmospheric concentrations of CUPs were driven by agricultural activities while secondary sources such as volatilization from surfaces governed the atmospheric concentrations of OCPs. Moreover, clear differences were observed in <span class="hlt">gas</span>-particle partitioning; CUP partitioning was influenced by adsorption onto mineral surfaces while OCPs were <span class="hlt">mainly</span> partitioning to aerosols through absorption. A predictive method for estimating the <span class="hlt">gas</span>-particle partitioning has been derived and is proposed for polar and non-polar pesticides. Finally, while OCPs and the majority of CUPs were largely found on fine particles, four CUPs (carbendazim, isoproturon, prochloraz, and terbuthylazine) had higher concentrations on coarse particles ( > 3.0 µm), which may be related to the pesticide application technique. This finding is particularly important and should be further investigated given that large particles result in lower risks from inhalation (regardless the toxicity of the pesticide) and lower potential for long-range atmospheric transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28018125','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28018125"><span>CFD analysis on <span class="hlt">gas</span> <span class="hlt">distribution</span> for different scrubber redirection configurations in sump cut.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zheng, Y; Organiscak, J A; Zhou, L; Beck, T W; Rider, J P</p> <p>2015-01-01</p> <p>The National Institute for Occupational Safety and Health's Office of Mine Safety and Health Research recently developed a series of models using computational fluid dynamics (CFD) to study the <span class="hlt">gas</span> <span class="hlt">distribution</span> around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations. CFD models using Species Transport Model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side of the continuous miner; 100 percent of the discharge redirected back toward the face, but divided equally to both sides of the machine; and 15 percent of the discharge redirected toward the face on the off-curtain side of the machine, with 85 percent directed into the return. These models were compared against a model with a conventional scrubber discharge, where air is directed away from the face into the return. The CFD models were calibrated and validated based on experimental data and accurately predicted sulfur hexafluoride (SF6) <span class="hlt">gas</span> levels at four <span class="hlt">gas</span> monitoring locations. One additional prediction model was simulated to consider a different scrubber discharge angle for the 100 percent redirected, equally divided case. These models identified relatively high gassy areas around the continuous miner, which may not warrant their use in coal mines with medium to high methane liberation rates. This paper describes the methodology used to develop the CFD models, and the validation of the models based on experimental data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5178874','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5178874"><span>CFD analysis on <span class="hlt">gas</span> <span class="hlt">distribution</span> for different scrubber redirection configurations in sump cut</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zheng, Y.; Organiscak, J.A.; Zhou, L.; Beck, T.W.; Rider, J.P.</p> <p>2016-01-01</p> <p>The National Institute for Occupational Safety and Health’s Office of Mine Safety and Health Research recently developed a series of models using computational fluid dynamics (CFD) to study the <span class="hlt">gas</span> <span class="hlt">distribution</span> around a continuous mining machine with various fan-powered flooded bed scrubber discharge configurations. CFD models using Species Transport Model without reactions in FLUENT were constructed to evaluate the redirection of scrubber discharge toward the mining face rather than behind the return curtain. The following scenarios are considered in this study: 100 percent of the discharge redirected back toward the face on the off-curtain side of the continuous miner; 100 percent of the discharge redirected back toward the face, but divided equally to both sides of the machine; and 15 percent of the discharge redirected toward the face on the off-curtain side of the machine, with 85 percent directed into the return. These models were compared against a model with a conventional scrubber discharge, where air is directed away from the face into the return. The CFD models were calibrated and validated based on experimental data and accurately predicted sulfur hexafluoride (SF6) <span class="hlt">gas</span> levels at four <span class="hlt">gas</span> monitoring locations. One additional prediction model was simulated to consider a different scrubber discharge angle for the 100 percent redirected, equally divided case. These models identified relatively high gassy areas around the continuous miner, which may not warrant their use in coal mines with medium to high methane liberation rates. This paper describes the methodology used to develop the CFD models, and the validation of the models based on experimental data. PMID:28018125</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26ES...44d2002M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26ES...44d2002M"><span>Determination of Shale Volume and <span class="hlt">Distribution</span> Patterns and Effective Porosity from Well Log Data Based On Cross-Plot Approach for A Shaly Carbonate <span class="hlt">Gas</span> Reservoir</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moradi, Siyamak; Moeini, Mohammad; Kamal Ghassem al-Askari, Mohammad; Hamed Mahvelati, Elaheh</p> <p>2016-10-01</p> <p>Determination of shale volume <span class="hlt">distribution</span> is one of the most important factors that has to be considered in formation evaluation, since existence of shale reduces effective porosity and permeability of the reservoir. In this paper, shale volume and <span class="hlt">distribution</span> (dispersed, laminar and structural) and formation effective porosity are estimated from well log data and cross-plots. Results show that <span class="hlt">distribution</span> of shale is <span class="hlt">mainly</span> dispersed with few of laminar ones, and the quality of reservoir (effective porosity) decreases with depth resulting in low productivity of <span class="hlt">gas</span> wells drilled in lower zones. Good agreement of estimated shale volumes and effective porosities from neutron-density cross-plot with the values determined from gamma ray log (CGR) and core analysis demonstrates the accuracy and applicability of these plots in determination of petrophysical parameters from conventional log data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960000868','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960000868"><span>The frequency and <span class="hlt">distribution</span> of high-velocity <span class="hlt">gas</span> in the Galaxy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nichols, Joy S.</p> <p>1995-01-01</p> <p>The purpose of this study was to estimate the frequency and <span class="hlt">distribution</span> of high-velocity <span class="hlt">gas</span> in the Galaxy using UV absorption line measurements from archival high-dispersion IUE spectra and to identify particularly interesting regions for future study. Approximately 500 spectra have been examined. The study began with the creation of a database of all 0 and B stars with b less than or = to 30 deg observed with IUE at high dispersion over its 18-year lifetime. The original database of 2500 unique objects was reduced to 1200 objects which had optimal exposures available. The next task was to determine the distances of these stars so the high-velocity structures could be mapped in the Galaxy. Spectroscopic distances were calculated for each star for which photometry was available. The photometry was acquired for each star using the SIMBAD database. Preference was given to the ubvy system where available; otherwise the UBV system was used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/269968','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/269968"><span>CAIS standard manual. System number 26. Industrial <span class="hlt">gas</span> storage and <span class="hlt">distribution</span> systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p></p> <p>1995-04-28</p> <p>At this installation the list of facilities to be surveyed, including infrastructure, will be addressed on the basis of 32 unique systems that form the CAIS Engineering Deficiency Standards and Inspection Methods document. Each system deals with a specific technical aspect of the facility to be surveyed. Within each system a further breakdown is made to subsystems, each having a related list of components. Detailed observations of the listed defects are provided so as to allow the entry of observed quantification data. A DOD CAIS manual is provided for each of the 32 systems with an internal organization. The System Tree is a graphical representation of the Work Breakdown Structure, showing system, subsystem and component relationships for the Industrial <span class="hlt">Gas</span> Storage and <span class="hlt">Distribution</span> System.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......290K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......290K"><span>Investigation of Colorless <span class="hlt">Distributed</span> Combustion (CDC) with Swirl for <span class="hlt">Gas</span> Turbine Application</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khalil Hasan, Ahmed Essam ElDin</p> <p></p> <p>Colorless <span class="hlt">Distributed</span> Combustion (CDC) with swirl is investigated for <span class="hlt">gas</span> turbine engine applications due to its benefits for ultra-low pollutants emission, improved pattern factor and thermal field uniformity, low noise emission, and stable combustion with the alleviation of combustion instabilities. Adequate and fast mixing between the injected air and internally recirculated hot reactive gases to form hot and diluted oxidant is critical for CDC, followed by rapid mixing with the fuel. This results in <span class="hlt">distributed</span> reaction zone instead of a concentrated thin flame front as observed in conventional diffusion flames, leading to avoidance of hot spot regions and providing reduced NOx and CO emissions. The focus of this dissertation is to develop and demonstrate CDC in a cylindrical combustor for application to stationary <span class="hlt">gas</span> turbine combustors. The dissertation examines the sequential development of ultra-low emission colorless <span class="hlt">distributed</span> combustor operating at a nominal thermal intensity of 36MW/m3-atm. Initially, the role of swirl is evaluated through comparing the performance of swirling and non-swirling configurations with focus on pollutants emission, stability, and isothermal flowfield through particle image velocimetry. Different fuel injection locations have also been examined, and based on performance a swirling configuration have been down selected for further investigations demonstrating emissions as low as 1 PPM of NO with a 40% reduction compared to non-swirling configuration. Further investigations were performed to outline the impact of inlet air temperature and combustor pressure on reaction <span class="hlt">distribution</span> and combustor performance. Next, Fuel flexibility has been examined with view to develop CDC combustors that can handle different gaseous and liquid fuels, both traditional and renewable. These fuels included diluted methane, hydrogen enriched methane, propane, ethanol, kerosene, JP-8, Hydrogenated Renewable Jet fuel, and novel biofuel. Swirling CDC</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1208717','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1208717"><span>The Case for Natural <span class="hlt">Gas</span> Fueled Solid Oxide Fuel Cell Power Systems for <span class="hlt">Distributed</span> Generation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chick, Lawrence A.; Weimar, Mark R.; Whyatt, Greg A.; Powell, Michael R.</p> <p>2015-02-01</p> <p>Natural-<span class="hlt">gas</span>-fueled solid oxide fuel cell (NGSOFC) power systems yield electrical conversion efficiencies exceeding 60% and may become a viable alternative for <span class="hlt">distributed</span> generation (DG) if stack life and manufacturing economies of scale can be realized. Currently, stacks last approximately 2 years and few systems are produced each year because of the relatively high cost of electricity from the systems. If mass manufacturing (10,000 units per year) and a stack life of 15 years can be reached, the cost of electricity from an NGSOFC system is estimated to be about 7.7 ¢/kWh, well within the price of commercial and residential retail prices at the national level (9.9-10¢/kWh and 11-12 ¢/kWh, respectively). With an additional 5 ¢/kWh in estimated additional benefits from DG, NGSOFC could be well positioned to replace the forecasted 59-77 gigawatts of capacity loss resulting from coal plant closures due to stricter emissions regulations and low natural <span class="hlt">gas</span> prices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...833..283L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...833..283L"><span>The Cosmic Evolution of the Metallicity <span class="hlt">Distribution</span> of Ionized <span class="hlt">Gas</span> Traced by Lyman Limit Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehner, Nicolas; O'Meara, John M.; Howk, J. Christopher; Prochaska, J. Xavier; Fumagalli, Michele</p> <p>2016-12-01</p> <p>We present the first results from our KODIAQ Z survey aimed at determining the metallicity <span class="hlt">distribution</span> and physical properties of the z≳ 2 partial and full Lyman limit systems (pLLSs and LLSs; 16.2≤slant {log}{N}{{H}{{I}}}\\lt 19), which are probed of the interface regions between the intergalactic medium (IGM) and galaxies. We study 31 H i-selected pLLSs and LLSs at 2.3\\lt z\\lt 3.3 observed with Keck/HIRES in absorption against background QSOs. We compare the column densities of metal ions to H i and use photoionization models to assess the metallicity. The metallicity <span class="hlt">distribution</span> of the pLLSs/LLSs at 2.3\\lt z\\lt 3.3 is consistent with a unimodal <span class="hlt">distribution</span> peaking at [{{X}}/{{H}}]≃ -2. The metallicity <span class="hlt">distribution</span> of these absorbers therefore evolves markedly with z since at z≲ 1 it is bimodal with peaks at [{{X}}/{{H}}]≃ -1.8 and -0.3. There is a substantial fraction (25%-41%) of pLLSs/LLSs with metallicities well below those of damped Lyα absorbers (DLAs) at any studied z from z≲ 1 to z˜ 2-4, implying reservoirs of metal-poor, cool, dense <span class="hlt">gas</span> in the IGM/galaxy interface at all z. However, the <span class="hlt">gas</span> probed by pLLSs and LLSs is rarely pristine, with a fraction of 3%-18% for pLLSs/LLSs with [{{X}}/{{H}}]≤slant -3. We find C/α enhancement in several pLLSs and LLSs in the metallicity range -2≲ [{{X}}/{{H}}]≲ -0.5, where C/α is 2-5 times larger than observed in Galactic metal-poor stars or high-redshift DLAs at similar metallicities. This is likely caused by preferential ejection of carbon from metal-poor galaxies into their surroundings.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994JCHyd..16..359I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994JCHyd..16..359I"><span>Effect of liquid <span class="hlt">distribution</span> on <span class="hlt">gas</span>-water phase mass transfer in an unsaturated sand during infiltration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Imhoff, Paul T.; Jaffé, Peter R.</p> <p>1994-09-01</p> <p><span class="hlt">Gas</span>-water phase mass transfer was examined in a homogeneous sand with both the <span class="hlt">gas</span> and water phase mobile: water was infiltrated from the top of the sand column while benzene-laden air flowed upward from the bottom. Mass-transfer limitations for this situation may be important for applications of bioventing, where water and nutrients are added at the ground surface simultaneously with induced air movement to carry oxygen and volatile organics to microbial populations. <span class="hlt">Gas</span>- and water-phase samples indicate that <span class="hlt">gas</span>-water phase mass transfer was sufficiently fast that equilibrium between <span class="hlt">gas</span> and water phases was achieved at all sampling locations within the porous medium. Lower-bound estimates for the <span class="hlt">gas</span>-water mass-transfer rate coefficient show that mass transfer was at least 10-40 times larger than predictions made from an empirical model developed for <span class="hlt">gas</span>-water phase mass transfer in an identical porous medium. A water-phase tracer test demonstrates that water flow was much more uniform in this study than in those earlier experiments, which is a likely explanation for the differing rates of <span class="hlt">gas</span>-water phase mass transfer. It is hypothesized that the liquid <span class="hlt">distribution</span> in previous laboratory experiments was less uniform because of preferential flow paths due to wetting front instabilities. <span class="hlt">Gas</span>-water phase mass-transfer rate coefficients reported in this investigation are for an ideal situation of uniform water infiltration: mass-transfer rates in field soils are expected to be significantly smaller.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......104M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......104M"><span>Thermodynamic Modeling and Dispatch of <span class="hlt">Distributed</span> Energy Technologies including Fuel Cell -- <span class="hlt">Gas</span> Turbine Hybrids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McLarty, Dustin Fogle</p> <p></p> <p><span class="hlt">Distributed</span> energy systems are a promising means by which to reduce both emissions and costs. Continuous generators must be responsive and highly efficiency to support building dynamics and intermittent on-site renewable power. Fuel cell -- <span class="hlt">gas</span> turbine hybrids (FC/GT) are fuel-flexible generators capable of ultra-high efficiency, ultra-low emissions, and rapid power response. This work undertakes a detailed study of the electrochemistry, chemistry and mechanical dynamics governing the complex interaction between the individual systems in such a highly coupled hybrid arrangement. The mechanisms leading to the compressor stall/surge phenomena are studied for the increased risk posed to particular hybrid configurations. A novel fuel cell modeling method introduced captures various spatial resolutions, flow geometries, stack configurations and novel heat transfer pathways. Several promising hybrid configurations are analyzed throughout the work and a sensitivity analysis of seven design parameters is conducted. A simple estimating method is introduced for the combined system efficiency of a fuel cell and a turbine using component performance specifications. Existing solid oxide fuel cell technology is capable of hybrid efficiencies greater than 75% (LHV) operating on natural <span class="hlt">gas</span>, and existing molten carbonate systems greater than 70% (LHV). A dynamic model is calibrated to accurately capture the physical coupling of a FC/GT demonstrator tested at UC Irvine. The 2900 hour experiment highlighted the sensitivity to small perturbations and a need for additional control development. Further sensitivity studies outlined the responsiveness and limits of different control approaches. The capability for substantial turn-down and load following through speed control and flow bypass with minimal impact on internal fuel cell thermal <span class="hlt">distribution</span> is particularly promising to meet local demands or provide dispatchable support for renewable power. Advanced control and dispatch</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JPhD...34.2135D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JPhD...34.2135D"><span>Modelling the laser fusion cutting process: II. <span class="hlt">Distribution</span> of supersonic <span class="hlt">gas</span> flow field inside the cut kerf</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Duan, J.; Man, H. C.; Yue, T. M.</p> <p>2001-07-01</p> <p>A mathematical model is developed to calculate the <span class="hlt">distribution</span> of the <span class="hlt">gas</span> flow field at the entrance, inside and exit of a laser cut kerf for inlet stagnation pressures ≥5 bar for an inert assist <span class="hlt">gas</span> jet exiting from a supersonic nozzle. A two-dimensional analytical method is adopted to locate approximately the position and shape of the detached shock above the cutting front surface according to the geometrical shape of the cutting front. A method of two-dimensional characteristics is applied to calculate the <span class="hlt">gas</span> flow field <span class="hlt">distribution</span> along the cutting front. The calculated results of the flow field <span class="hlt">distribution</span> are simulated by the computer and can be used to estimate and analyse the cut-edge quality under different cutting conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MMTB...47..948C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MMTB...47..948C"><span>The Effects of Bottom Blowing <span class="hlt">Gas</span> Flow Rate <span class="hlt">Distribution</span> During the Steelmaking Converter Process on Mixing Efficiency</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chu, Kuan-Yu; Chen, Hsing-Hao; Lai, Po-Han; Wu, Hsuan-Chung; Liu, Yung-Chang; Lin, Chi-Cheng; Lu, Muh-Jung</p> <p>2016-04-01</p> <p>Featuring the advantages of top-blown and bottom-blown oxygen converters, top and bottom combined blown converters are mainstream devices used in steelmaking converter. This study adopted the FLUENT software to develop a numerical model that simulates 3D multiphase flows of <span class="hlt">gas</span> (air and argon), liquid steel, and slag. Ten numerical experiments were conducted to analyze the effects that the bottom blowing <span class="hlt">gas</span> flow rate <span class="hlt">distribution</span> patterns (uniform, linear fixed total flow rate, linear fixed maximal flow rate, and V-type) and bottom blowing <span class="hlt">gas</span> flow <span class="hlt">distribution</span> gradients of combined blown converters exert on slag surface stirring heights, flow field patterns, simulation system dynamic pressures, mixing time, and liquid steel-slag interface velocity. The simulation results indicated that the mixing efficiency was highest for the linear fixed total flow rate, followed by the linear fixed maximal flow rate, V-type, and uniform patterns. The bottom blowing <span class="hlt">gas</span> flow rate <span class="hlt">distribution</span> exhibited linear patterns and large gradients, and high bottom blowing total flow rates increased the mixing efficiency substantially. In addition, the results suggested that even when bottom blowing total flow rate was reduced, adopting effective bottom blowing <span class="hlt">gas</span> flow rate <span class="hlt">distribution</span> patterns and gradients could improve the mixing efficiency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JPS...194..328K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JPS...194..328K"><span>Uneven <span class="hlt">gas</span> diffusion layer intrusion in <span class="hlt">gas</span> channel arrays of proton exchange membrane fuel cell and its effects on flow <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kandlikar, S. G.; Lu, Z.; Lin, T. Y.; Cooke, D.; Daino, M.</p> <p></p> <p>Intrusion of the <span class="hlt">gas</span> diffusion layer (GDL) into <span class="hlt">gas</span> channels due to fuel cell compression has a major impact on the <span class="hlt">gas</span> flow <span class="hlt">distribution</span>, fuel cell performance and durability. In this work, the effect of compression resulting in GDL intrusion in individual parallel PEMFC channels is investigated. The intrusion is determined using two methods: an optical measurement in both the in-plane and through-plane directions of GDL, as well as an analytical fluid flow model based on individual channel flow rate measurements. The intrusion measurements and estimates obtained from these methods agree well with each other. An uneven <span class="hlt">distribution</span> of GDL intrusion into individual parallel channels is observed. A non-uniform compression force <span class="hlt">distribution</span> derived from the clamping bolts causes a higher intrusion in the end channels. The heterogeneous GDL structure and physical properties may also contribute to the uneven GDL intrusion. As a result of uneven intrusion <span class="hlt">distribution</span>, severe flow maldistribution and increased pressure drop have been observed. The intrusion data can be further used to determine the mechanical properties of GDL materials. Using the finite element analysis software program ANSYS, the Young's modulus of the GDL from these measurements is estimated to be 30.9 MPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMIN31C..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMIN31C..07B"><span>Developing a Framework for <span class="hlt">Distributed</span> and Dynamic Data Sharing Among the Coastal Ocean Community: Gulf of <span class="hlt">Maine</span> Spatial Data Project and the Open IOOS Portal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bogden, P.; Shyka, T.; McIlhagga, D.</p> <p>2005-12-01</p> <p>In the past year the Gulf of <span class="hlt">Maine</span> Ocean Observing System (GoMOOS), the Southeastern Universities Research Association (SURA) and DM Solutions Group worked with multiple government, academic and private industry partners to develop regional and national <span class="hlt">distributed</span> data-sharing frameworks for the coastal ocean community. These projects were initiated by a joint FGDC and GeoConnections grant for the Gulf of <span class="hlt">Maine</span> Framework Data Project. This project catalyzed activities in the Gulf of <span class="hlt">Maine</span> region, building upon the years of effort at the Open Geospatial Consortium (OGC) and related developments in the NSDI and the Canadian Geospatial Data Infrastructure. This one year demonstration project resulted in a <span class="hlt">distributed</span> framework data resource that spans international borders and connects more than a dozen regional, State, Federal, Provincial and other types of organizations (www.gommap.org). Even though the project funding has ended the regional partnership continues to grow and has formed the basis for the Gulf of <span class="hlt">Maine</span> Ocean Data Partnership. Additionally, many organizations within the Canadian government are looking at this project as a model for future data sharing collaborations. Concurrent to the Gulf of <span class="hlt">Maine</span> project, the SURA Coastal Ocean Observing and Prediction (SCOOP) program initiative leveraged the developing data sharing capacity to coordinate and develop the OpenIOOS portal (www.openioos.org), which demonstrates the capacity of the Integrated Ocean Observing System and starts putting the "I" in IOOS in an OGC-compliant fashion. These efforts have engaged the ocean-science community on the national scale. Indeed, a culture change seems to be underway that will have important implications for our nation's response to recommendations from the U.S. Commission on Ocean Policy. This presentation will discuss the successes and lessons learned from these related projects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995A%26A...295..487L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995A%26A...295..487L"><span>The Thumbprint nebula: The <span class="hlt">distribution</span> of molecular <span class="hlt">gas</span> and dust in a regular BOK globule</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehtinen, K.; Mattila, K.; Schnur, G. F. O.; Prusti, T.</p> <p>1995-03-01</p> <p>We have studied a regular bright-rimmed globule called Thumbprint Nebula, TPN, (size approximately 0.18 pc, distance approximately 200 pc) in millimeter molecular lines (CO isotopic lines), at optical wavelengths (scanned Schmidt plates) and at infrared wavelengths (IRAS maps and scans). The molecular line observations have been made with the Swedish-ESO Submillimeter Telescope (SEST) in (12)CO (J = 1-0) and (J = 2-1), (13)CO (J = 1-0) and (J = 2-1), C(18)O (J = 1-0), C(17)O (J = 1-0), CS (J = 2-1) and HNC (J = 1-0) transitions. These observations reveal a centrally condensed cloud with an excitation temperature of Tex approximately equal to 6.6 K, and a mass of 6 solar mass. There is indication of a cloud rotation with a rotation rate of approximately 0.6 km/s/pc, as measured using (13)CO lines. Optical surface brightness <span class="hlt">distribution</span> as measured from blue and red European Southern Observatory (ESO/SRC) Schmidt plates has been used to determine the <span class="hlt">distribution</span> of the dust particles in comparison with the <span class="hlt">distribution</span> of the <span class="hlt">gas</span> component. The position of the surface brightness minimum, which corresponds to the dust density maximum, is found to be about 40 sec to 50 sec north of the (13)CO and C(18)O column density maximum. We have made infrared surface brightness maps using the IRAS Sky Survey Atlas (ISSA) survey plates at 12, 25, 60 and 100 micrometers and extracted individual IRAS scans crossing the TPN. The globule is seen at 100 and 60 micrometers but the dust is apparently too cold to be visible at shorter wavelengths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ERL.....9b4017H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ERL.....9b4017H"><span>A perspective on cost-effectiveness of greenhouse <span class="hlt">gas</span> reduction solutions in water <span class="hlt">distribution</span> systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hendrickson, Thomas P.; Horvath, Arpad</p> <p>2014-01-01</p> <p>Water <span class="hlt">distribution</span> systems (WDSs) face great challenges as aging infrastructures require significant investments in rehabilitation, replacement, and expansion. Reducing environmental impacts as WDSs develop is essential for utility managers and policy makers. This study quantifies the existing greenhouse <span class="hlt">gas</span> (GHG) footprint of common WDS elements using life-cycle assessment (LCA) while identifying the greatest opportunities for emission reduction. This study addresses oversights of the related literature, which fails to capture several WDS elements and to provide detailed life-cycle inventories. The life-cycle inventory results for a US case study utility reveal that 81% of GHGs are from pumping energy, where a large portion of these emissions are a result of <span class="hlt">distribution</span> leaks, which account for 270 billion l of water losses daily in the United States. Pipe replacement scheduling is analyzed from an environmental perspective where, through incorporating leak impacts, a tool reveals that optimal replacement is no more than 20 years, which is in contrast to the US average of 200 years. Carbon abatement costs (CACs) are calculated for different leak reduction scenarios for the case utility that range from -130 to 35 t-1 CO2(eq). Including life-cycle modeling in evaluating pipe materials identified polyvinyl chloride (PVC) and cement-lined ductile iron (DICL) as the Pareto efficient options, however; utilizing PVC presents human health risks. The model developed for the case utility is applied to California and Texas to determine the CACs of reducing leaks to 5% of <span class="hlt">distributed</span> water. For California, annual GHG savings from reducing leaks alone (3.4 million tons of CO2(eq)) are found to exceed California Air Resources Board’s estimate for energy efficiency improvements in the state’s water infrastructure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A43F0353S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A43F0353S"><span>Impact of routine episodic emissions on the expected frequency <span class="hlt">distribution</span> of emissions from oil and <span class="hlt">gas</span> production sources.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, N.; Blewitt, D.; Hebert, L. B.</p> <p>2015-12-01</p> <p>In coordination with oil and <span class="hlt">gas</span> operators, we developed a high resolution (< 1 min) simulation of temporal variability in well-pad oil and <span class="hlt">gas</span> emissions over a year. We include routine emissions from condensate tanks, dehydrators, pneumatic devices, fugitive leaks and liquids unloading. We explore the variability in natural <span class="hlt">gas</span> emissions from these individual well-pad sources, and find that routine short-term episodic emissions such as tank flashing and liquids unloading result in the appearance of a skewed, or 'fat-tail' <span class="hlt">distribution</span> of emissions, from an individual well-pad over time. Additionally, we explore the expected variability in emissions from multiple wells with different raw <span class="hlt">gas</span> composition, <span class="hlt">gas</span>/liquids production volumes and control equipment. Differences in well-level composition, production volume and control equipment translate into differences in well-level emissions leading to a fat-tail <span class="hlt">distribution</span> of emissions in the absence of operational upsets. Our results have several implications for recent studies focusing on emissions from oil and <span class="hlt">gas</span> sources. Time scale of emission estimates are important and have important policy implications. Fat tail <span class="hlt">distributions</span> may not be entirely driven by avoidable mechanical failures, and are expected to occur under routine operational conditions from short-duration emissions (e.g., tank flashing, liquid unloading). An understanding of the expected <span class="hlt">distribution</span> of emissions for a particular population of wells is necessary to evaluate whether the observed <span class="hlt">distribution</span> is more skewed than expected. Temporal variability in well-pad emissions make comparisons to annual average emissions inventories difficult and may complicate the interpretation of long-term ambient fenceline monitoring data. Sophisticated change detection algorithms will be necessary to identify when true operational upsets occur versus routine short-term emissions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1045758','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1045758"><span>Updated greenhouse <span class="hlt">gas</span> and criteria air pollutant emission factors and their probability <span class="hlt">distribution</span> functions for electricity generating units</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cai, H.; Wang, M.; Elgowainy, A.; Han, J.</p> <p>2012-07-06</p> <p>Greenhouse <span class="hlt">gas</span> (CO{sub 2}, CH{sub 4} and N{sub 2}O, hereinafter GHG) and criteria air pollutant (CO, NO{sub x}, VOC, PM{sub 10}, PM{sub 2.5} and SO{sub x}, hereinafter CAP) emission factors for various types of power plants burning various fuels with different technologies are important upstream parameters for estimating life-cycle emissions associated with alternative vehicle/fuel systems in the transportation sector, especially electric vehicles. The emission factors are typically expressed in grams of GHG or CAP per kWh of electricity generated by a specific power generation technology. This document describes our approach for updating and expanding GHG and CAP emission factors in the GREET (Greenhouse Gases, Regulated Emissions, and Energy Use in Transportation) model developed at Argonne National Laboratory (see Wang 1999 and the GREET website at http://greet.es.anl.gov/<span class="hlt">main</span>) for various power generation technologies. These GHG and CAP emissions are used to estimate the impact of electricity use by stationary and transportation applications on their fuel-cycle emissions. The electricity generation mixes and the fuel shares attributable to various combustion technologies at the national, regional and state levels are also updated in this document. The energy conversion efficiencies of electric generating units (EGUs) by fuel type and combustion technology are calculated on the basis of the lower heating values of each fuel, to be consistent with the basis used in GREET for transportation fuels. On the basis of the updated GHG and CAP emission factors and energy efficiencies of EGUs, the probability <span class="hlt">distribution</span> functions (PDFs), which are functions that describe the relative likelihood for the emission factors and energy efficiencies as random variables to take on a given value by the integral of their own probability <span class="hlt">distributions</span>, are updated using best-fit statistical curves to characterize the uncertainties associated with GHG and CAP emissions in life</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10192410','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10192410"><span>Determination of alkylmethylphosphonic acids, the <span class="hlt">main</span> metabolites of organophosphorus nerve agents, in biofluids by <span class="hlt">gas</span> chromatography-mass spectrometry and liquid-liquid-solid-phase-transfer-catalyzed pentafluorobenzylation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Miki, A; Katagi, M; Tsuchihashi, H; Yamashita, M</p> <p>1999-01-01</p> <p>A simple <span class="hlt">gas</span> chromatography-mass spectrometry (GC-MS) procedure has been developed for the <span class="hlt">main</span> metabolites of organophosphorus nerve agents, alkylmethylphosphonic acids (AMPAs; alkyl = Et, i-Pr, and pinacolyl) in biofluids via extractive pentafluorobenzylation. The derivatization was carried out under liquid-liquid-solid-phase-transfer conditions using a polymer-bound tri-n-butylmethylphosphonium bromide as a catalyst. AMPAs in aqueous samples were semiquantitatively extracted into a small-volume organic layer as their pentafluorobenzyl derivatives at pH 4.5 (85 degrees C). Sample pretreatments for urine, serum, and saliva were each examined to minimize matrix interference. The detection limits of APMAs by electron-impact ionization GC-MS were around 50 ng/mL and 2.5-10 ng/mL in the full-scan and selected-ion monitoring modes, respectively. In order to detect trace-level AMPAs, negative-ion chemical ionization (NICI) was also employed to enhance sensitivity. The detection limits of AMPAs in biofluids were typically 60 pg/mL by GC-NICI-MS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115623&keyword=global+AND+strategy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78770501&CFTOKEN=10759522','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=115623&keyword=global+AND+strategy&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=78770501&CFTOKEN=10759522"><span>METHANE EMISSIONS FROM THE NATURAL <span class="hlt">GAS</span> INDUSTRY VOLUME 10: METERING AND PRESSURE REGULATING STATIONS IN NATURAL <span class="hlt">GAS</span> TRANSMISSIONS AND <span class="hlt">DISTRIBUTION</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural <span class="hlt">gas</span> industry for the base year. The objective was to determine CH4 emissions from the wellhead and ending downstream at the customer's meter. The accur...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15648387','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15648387"><span>Measurement of ultrafine particle size <span class="hlt">distributions</span> from coal-, oil-, and <span class="hlt">gas</span>-fired stationary combustion sources.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chang, M C Oliver; Chow, Judith C; Watson, John G; Hopke, Philip K; Yi, Seung-Muk; England, Glenn C</p> <p>2004-12-01</p> <p>Currently, we have limited knowledge of the physical and chemical properties of emitted primary combustion aerosols and the changes in those properties caused by nucleation, condensation growth of volatile species, and particle coagulations under dilution and cooling in the ambient air. A dilution chamber was deployed to sample exhaust from a pilot-scale furnace burning various fuels at a nominal heat input rate of 160 kW/h(-1) and 3% excess oxygen. The formation mechanisms of particles smaller than 420 nm in electrical mobility diameter were experimentally investigated by measurement with a Scanning Mobility Particle Sizer (SMPS) as a function of aging times, dilution air ratios, combustion exhaust temperatures, and fuel types. Particle formation in the dilution process is a complex mixture of nucleation, coagulation, and condensational growth, depending on the concentrations of available condensable species and solid or liquid particles (such as soot, ash) in combustion exhausts. The measured particle size <span class="hlt">distributions</span> in number concentrations measured show peaks of particle number concentrations for medium sulfur bituminous coal, No. 6 fuel oil, and natural <span class="hlt">gas</span> at 40-50 nm, 70-100 nm, and 15-25 nm, respectively. For No. 6 fuel oil and coal, the particle number concentration is constant in the range of a dilution air ratio of 50, but the number decreases as the dilution air ratio decreases to 10. However, for natural <span class="hlt">gas</span>, the particle number concentration is higher at a dilution air ratio of 10 and decreases at dilution air ratios of 20-50. At a dilution air ratio of 10, severe particle coagulation occurs in a relatively short time. Samples taken at different combustion exhaust temperatures for these fuel types show higher particle number concentrations at 645 K than at 450 K. As the aging time of particles increases, the particles increase in size and the number concentrations decrease. The largest gradient of particle number <span class="hlt">distribution</span> occurs within the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001MNRAS.326.1475M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001MNRAS.326.1475M"><span>Damped Lyman alpha systems and galaxy formation models - I. The radial <span class="hlt">distribution</span> of cold <span class="hlt">gas</span> at high z</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maller, Ariyeh H.; Prochaska, Jason X.; Somerville, Rachel S.; Primack, Joel R.</p> <p>2001-10-01</p> <p>We investigate the properties of damped Lyman α systems (DLAS) in semi-analytic models, focusing on whether the models can reproduce the kinematic properties of low-ionization metal lines described by Prochaska & Wolfe. We explore a variety of approaches for modelling the radial <span class="hlt">distribution</span> of the cold neutral <span class="hlt">gas</span> associated with the galaxies in our models, and find that our results are very sensitive to this ingredient. If we use an approach based on work by Fall & Efstathiou, in which the sizes of the discs are determined by conservation of angular momentum, we find that the majority of the DLAS correspond to a single galactic disc. These models generically fail to reproduce the observed <span class="hlt">distribution</span> of velocity widths. In alternative models in which the <span class="hlt">gas</span> discs are considerably more extended, a significant fraction of DLAS arise from lines of sight intersecting multiple <span class="hlt">gas</span> discs in a common halo. These models produce kinematics that fit the observational data, and also seem to agree well with the results of recent hydrodynamical simulations. Thus we conclude that cold dark matter based models of galaxy formation can be reconciled with the kinematic data, but only at the expense of the standard assumption that DLAS are produced by rotationally supported <span class="hlt">gas</span> discs whose sizes are determined by conservation of angular momentum. We suggest that the <span class="hlt">distribution</span> of cold <span class="hlt">gas</span> at high redshift may be dominated by another process, such as tidal streaming caused by mergers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JPS...323...37U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JPS...323...37U"><span>Performance enhancement of polymer electrolyte fuel cells by combining liquid removal mechanisms of a <span class="hlt">gas</span> diffusion layer with wettability <span class="hlt">distribution</span> and a <span class="hlt">gas</span> channel with microgrooves</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Utaka, Yoshio; Koresawa, Ryo</p> <p>2016-08-01</p> <p>Although polymer electrolyte fuel cells (PEFCs) are commercially available, there are still many problems that need to be addressed to improve their performance and increase their usage. At a high current density, generated water accumulates in the <span class="hlt">gas</span> diffusion layer and in the <span class="hlt">gas</span> channels of the cathode. This excess water obstructs oxygen transport, and as a result, cell performance is greatly reduced. To improve the cell performance, the effective removal of the generated water and the promotion of oxygen diffusion in the <span class="hlt">gas</span> diffusion layer (GDL) are necessary. In this study, two functions proposed in previous reports were combined and applied to a PEFC: a hybrid GDL to form an oxygen diffusion path using a wettability <span class="hlt">distribution</span> and a <span class="hlt">gas</span> separator with microgrooves to enhance liquid removal. For a PEFC with a hybrid GDL and a <span class="hlt">gas</span> separator with microgrooves, the concentration overvoltage of the PEFC was reduced, and the current density limit and maximum power density were increased compared with a conventional PEFC. Moreover, the stability of the cell voltage was markedly improved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=308821','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=308821"><span><span class="hlt">Distribution</span> and chemical fate of 36Cl-chlorine dioxide <span class="hlt">gas</span> during the fumigation of tomatoes and cantaloupe</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>The <span class="hlt">distribution</span> and chemical fate of 36Cl-ClO2 <span class="hlt">gas</span> subsequent to fumigation of tomatoes or cantaloupe was investigated as was major factors that affect the formation of chloroxyanion byproducts. Approximately 22% of the generated 36Cl-ClO2 was present on fumigated tomatoes after a 2-hour exposure t...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4449716','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4449716"><span>Influence of Flue <span class="hlt">Gas</span> Desulfurization Gypsum Amendments on Heavy Metal <span class="hlt">Distribution</span> in Reclaimed Sodic Soils</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe</p> <p>2015-01-01</p> <p>Abstract Although flue <span class="hlt">gas</span> desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal <span class="hlt">distributions</span> in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on <span class="hlt">distribution</span> profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780007101','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780007101"><span>Temperature <span class="hlt">distributions</span> and thermal stresses in a graded zirconia/metal <span class="hlt">gas</span> path seal system for aircraft <span class="hlt">gas</span> turbine engines</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Taylor, C. M.; Bill, R. C.</p> <p>1978-01-01</p> <p>A ceramic/metallic aircraft <span class="hlt">gas</span> turbine outer <span class="hlt">gas</span> path seal designed for improved engine performance was studied. Transient temperature and stress profiles in a test seal geometry were determined by numerical analysis. During a simulated engine deceleration cycle from sea-level takeoff to idle conditions, the maximum seal temperature occurred below the seal surface, therefore the top layer of the seal was probably subjected to tensile stresses exceeding the modulus of rupture. In the stress analysis both two- and three-dimensional finite element computer programs were used. Predicted trends of the simpler and more easily usable two-dimensional element programs were borne out by the three-dimensional finite element program results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJ...824...94R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...824...94R"><span>GARROTXA Cosmological Simulations of Milky Way-sized Galaxies: General Properties, Hot-<span class="hlt">gas</span> <span class="hlt">Distribution</span>, and Missing Baryons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Roca-Fàbrega, Santi; Valenzuela, Octavio; Colín, Pedro; Figueras, Francesca; Krongold, Yair; Velázquez, Héctor; Avila-Reese, Vladimir; Ibarra-Medel, Hector</p> <p>2016-06-01</p> <p>We introduce a new set of simulations of Milky Way (MW)-sized galaxies using the AMR code ART + hydrodynamics in a Λ cold dark matter cosmogony. The simulation series is called GARROTXA and it follows the formation of a halo/galaxy from z = 60 to z = 0. The final virial mass of the system is ˜7.4 × 1011 M ⊙. Our results are as follows. (a) Contrary to many previous studies, the circular velocity curve shows no central peak and overall agrees with recent MW observations. (b) Other quantities, such as M\\_\\ast (6 × 1010 M ⊙) and R d (2.56 kpc), fall well inside the observational MW range. (c) We measure the disk-to-total ratio kinematically and find that D/T = 0.42. (d) The cold-<span class="hlt">gas</span> fraction and star formation rate at z = 0, on the other hand, fall short of the values estimated for the MW. As a first scientific exploitation of the simulation series, we study the spatial <span class="hlt">distribution</span> of hot X-ray luminous <span class="hlt">gas</span>. We have found that most of this X-ray emitting <span class="hlt">gas</span> is in a halo-like <span class="hlt">distribution</span> accounting for an important fraction but not all of the missing baryons. An important amount of hot <span class="hlt">gas</span> is also present in filaments. In all our models there is not a massive disk-like hot-<span class="hlt">gas</span> <span class="hlt">distribution</span> dominating the column density. Our analysis of hot-<span class="hlt">gas</span> mock observations reveals that the homogeneity assumption leads to an overestimation of the total mass by factors of 3-5 or to an underestimation by factors of 0.7-0.1, depending on the used observational method. Finally, we confirm a clear correlation between the total hot-<span class="hlt">gas</span> mass and the dark matter halo mass of galactic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MmSAI..87..200R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MmSAI..87..200R"><span>YORP and collisional shaping of the sub-populations, rotation rate and size-frequency <span class="hlt">distributions</span> in the <span class="hlt">main</span>-belt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rossi, A.; Marzari, F.; Scheeres, D.; Jacobson, S.; Davis, D.</p> <p></p> <p>In the last several years a comprehensive asteroid-population-evolution model was developed incorporating both the YORP effect and collisional evolution \\citep{rossi_2009}, \\citep{marz_2011}, \\citep{jac_mnras}. From the results of this model we were able to match the observed <span class="hlt">main</span> belt rotation rate <span class="hlt">distribution</span> and to give a first plausible explanation of the observed excess of slow rotators, through a random walk-like evolution of the spin, induced by repeated collisions with small projectiles. Moreover, adding to the model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur; \\citealt{sch_2007}) and binary-asteroid evolution \\citep{jac_sch}, we first showed that the YORP-induced rotational-fission hypothesis has strong repercussions for the small size end of the <span class="hlt">main</span>-belt asteroid size-frequency <span class="hlt">distribution</span>. We also concluded that this hypothesis is consistent with observed asteroid-population statistics and with the observed sub-populations of binary asteroids, asteroid pairs and contact binaries. An overview of the results obtained, the modelling uncertainties and the ongoing work will be given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4732154','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4732154"><span>Realtime <span class="hlt">Gas</span> Emission Monitoring at Hazardous Sites Using a <span class="hlt">Distributed</span> Point-Source Sensing Infrastructure</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco</p> <p>2016-01-01</p> <p>This paper describes a <span class="hlt">distributed</span> point-source monitoring platform for <span class="hlt">gas</span> level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant’s critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events. PMID:26805832</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21337868','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21337868"><span>Spatially <span class="hlt">distributed</span> flame transfer functions for predicting combustion dynamics in lean premixed <span class="hlt">gas</span> turbine combustors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kim, K.T.; Lee, J.G.; Quay, B.D.; Santavicca, D.A.</p> <p>2010-09-15</p> <p>The present paper describes a methodology to improve the accuracy of prediction of the eigenfrequencies and growth rates of self-induced instabilities and demonstrates its application to a laboratory-scale, swirl-stabilized, lean-premixed, <span class="hlt">gas</span> turbine combustor. The influence of the spatial heat release <span class="hlt">distribution</span> is accounted for using local flame transfer function (FTF) measurements. The two-microphone technique and CH{sup *} chemiluminescence intensity measurements are used to determine the input (inlet velocity perturbation) and the output functions (heat release oscillation), respectively, for the local flame transfer functions. The experimentally determined local flame transfer functions are superposed using the flame transfer function superposition principle, and the result is incorporated into an analytic thermoacoustic model, in order to predict the linear stability characteristics of a given system. Results show that when the flame length is not acoustically compact the model prediction calculated using the local flame transfer functions is better than the prediction made using the global flame transfer function. In the case of a flame in the compact flame regime, accurate predictions of eigenfrequencies and growth rates can be obtained using the global flame transfer function. It was also found that the general response characteristics of the local FTF (gain and phase) are qualitatively the same as those of the global FTF. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26805832','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26805832"><span>Realtime <span class="hlt">Gas</span> Emission Monitoring at Hazardous Sites Using a <span class="hlt">Distributed</span> Point-Source Sensing Infrastructure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Manes, Gianfranco; Collodi, Giovanni; Gelpi, Leonardo; Fusco, Rosanna; Ricci, Giuseppe; Manes, Antonio; Passafiume, Marco</p> <p>2016-01-20</p> <p>This paper describes a <span class="hlt">distributed</span> point-source monitoring platform for <span class="hlt">gas</span> level and leakage detection in hazardous environments. The platform, based on a wireless sensor network (WSN) architecture, is organised into sub-networks to be positioned in the plant's critical areas; each sub-net includes a gateway unit wirelessly connected to the WSN nodes, hence providing an easily deployable, stand-alone infrastructure featuring a high degree of scalability and reconfigurability. Furthermore, the system provides automated calibration routines which can be accomplished by non-specialized maintenance operators without system reliability reduction issues. Internet connectivity is provided via TCP/IP over GPRS (Internet standard protocols over mobile networks) gateways at a one-minute sampling rate. Environmental and process data are forwarded to a remote server and made available to authenticated users through a user interface that provides data rendering in various formats and multi-sensor data fusion. The platform is able to provide real-time plant management with an effective; accurate tool for immediate warning in case of critical events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008Th%26Ae..15..381L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008Th%26Ae..15..381L"><span><span class="hlt">Gas</span> motion through porous objects with nonuniform local <span class="hlt">distribution</span> of heat-release sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levin, V. A.; Lutsenko, N. A.</p> <p>2008-09-01</p> <p>The <span class="hlt">gas</span> motion through porous objects in the gravity force field with a non-uniform <span class="hlt">distribution</span> of heat sources, which may arise as a result of natural or man-caused catastrophes (as the damaged power unit of the Chernobyl NPP), is investigated. The influence of different parameters of the heat-releasing zone on the process of cooling of such objects is analyzed with the aid of computational experiment. It is shown that the porous element heating is affected not only by the height of the heat-releasing zone and the heat-release intensity therein but also by the distance of the heat-releasing zone from the element inlet as well as by the width of the heat-releasing zone. The phenomenon of a reduction of the porous element heating with increasing distance of the heat-releasing zone from the porous element inlet is revealed. An ambiguous dependence of the porous object heating on the width of the heat-release zone is identified: at a growth of the heat-releasing zone width, the heating of the element may both increase and decrease depending on the distance of the heat-release zone from the element inlet.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050051745','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050051745"><span><span class="hlt">Gas</span>-liquid Phase <span class="hlt">Distribution</span> and Void Fraction Measurements Using the MRI</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Daidzic, N. E.; Schmidt, E.; Hasan, M. M.; Altobelli, S.</p> <p>2004-01-01</p> <p>We used a permanent-magnet MRI system to estimate the integral and spatially- and/or temporally-resolved void-fraction <span class="hlt">distributions</span> and flow patterns in <span class="hlt">gas</span>-liquid two-phase flows. Air was introduced at the bottom of the stagnant liquid column using an accurate and programmable syringe pump. Air flow rates were varied between 1 and 200 ml/min. The cylindrical non-conducting test tube in which two-phase flow was measured was placed in a 2.67 kGauss MRI with MRT spectrometer/imager. Roughly linear relationship has been obtained for the integral void-fraction, obtained by volume-averaging of the spatially-resolved signals, and the air flow rate in upward direction. The time-averaged spatially-resolved void fraction has also been obtained for the quasi-steady flow of air in a stagnant liquid column. No great accuracy is claimed as this was an exploratory proof-of-concept type of experiment. Preliminary results show that MRI a non-invasive and non-intrusive experimental technique can indeed provide a wealth of different qualitative and quantitative data and is especially well suited for averaged transport processes in adiabatic and diabatic multi-phase and/or multi-component flows.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JCrGr.360...12T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JCrGr.360...12T"><span>Numerical investigation of oxygen impurity <span class="hlt">distribution</span> during multicrystalline silicon crystal growth using a <span class="hlt">gas</span> flow guidance device</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Teng, Ying-Yang; Chen, Jyh-Chen; Lu, Chung-Wei; Chen, Chi-Yung</p> <p>2012-12-01</p> <p>Oxygen is one of the most important types of impurities that can cause thermal donor or light-induced degradation in mc-Si solar cells. The objective of this study is to investigate the effect that installing a <span class="hlt">gas</span> flow guidance device in a mc-Si crystal-growth furnace would have on the oxygen impurity <span class="hlt">distribution</span> in the melt during the growth process. The installation of such a <span class="hlt">gas</span> flow guidance device can enhance the <span class="hlt">gas</span> flow near the free surface, which would allow the argon to carry a greater amount of evaporated SiO <span class="hlt">gas</span> outside the furnace. Furthermore, the enhanced motion of the <span class="hlt">gas</span> flow also improves heat transfer near the free surface, which would make the melt vortex separate more easily. The separated melt vortex, which is located near the central region of the melt-crystal interface, directs any oxygen impurity towards the central region of the melt-crystal interface. This is why the oxygen concentration can be reduced by installing the <span class="hlt">gas</span> flow guidance device. The effectiveness of the <span class="hlt">gas</span> flow guidance device depends on the vertical distance between it and the free surface (h) as well as the gap between the crucible sidewall and the tip of the device (d). The effect on the oxygen concentration in the melt is significant when smaller values for h and d are adopted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11380516','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11380516"><span>Multiple inert <span class="hlt">gas</span> elimination technique for determining ventilation/perfusion <span class="hlt">distributions</span> in rat during normoxia, hypoxia and hyperoxia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alfaro, V; Roca-Acín, J; Palacios, L; Guitart, R</p> <p>2001-01-01</p> <p>1. The use of the multiple inert <span class="hlt">gas</span> elimination technique (MIGET) in quantifying ventilation/perfusion <span class="hlt">distributions</span> (V*A/Q*) in small animals, such as the rat, may cause results to be biased due to haemodilution produced by the large volume of liquid infused intravenously. 2. We tested two methods of administering inert gases in rats using the MIGET: (i) standard continuous intravenous administration of inert gases (method A); and (ii) a new method based on the physicochemical properties of each inert <span class="hlt">gas</span> (method B). This method included acute simultaneous inert <span class="hlt">gas</span> administration using three pathways: inhalation, intravenous infusion and rectal infusion. Both MIGET methods were applied to obtain data while breathing three different inspiratory fractions of oxygen (FIO2): normoxia, hypoxia and hyperoxia. 3. Inert <span class="hlt">gas</span> levels obtained from blood or expired air samples were sufficient for chromatographic measurement, at least during a 2 h period. The V*A/Q* <span class="hlt">distributions</span> reported using both methods were acceptable for all the physiological conditions studied; therefore, the alternative method used here may be useful in further MIGET studies in rats because haemodilution resulting from continuous intravenous infusion of less-soluble gases can be avoided. 4. Normoxic rats showed lower mean values of the V*A/Q* ratio of ventilation <span class="hlt">distribution</span> and higher mean values of the V*A/Q* ratio of perfusion <span class="hlt">distribution</span> with the usual method of inert <span class="hlt">gas</span> administration (method A). These non-significant differences were observed under almost all physiological conditions studied and they could be caused by haemodilution. Nevertheless, the effect of interindividual differences cannot be discarded. An additional effect of the low haematocrit on cardiovascular changes due to low FIO2, such as pulmonary vasoconstriction or increased cardiac output, may explain the lower dispersion of perfusion <span class="hlt">distributions</span> found in group A during hypoxia.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030064149','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030064149"><span>Cooling of <span class="hlt">Gas</span> Turbines. 6; Computed Temperature <span class="hlt">Distribution</span> Through Cross Section of Water-Cooled Turbine Blade</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Livingood, John N. B.; Sams, Eldon W.</p> <p>1947-01-01</p> <p>A theoretical analysis of the cross-sectional temperature <span class="hlt">distribution</span> of a water-cooled turbine blade was made using the relaxation method to solve the differential equation derived from the analysis. The analysis was applied to specific turbine blade and the studies icluded investigations of the accuracy of simple methods to determine the temperature <span class="hlt">distribution</span> along the mean line of the rear part of the blade, of the possible effect of varying the perimetric <span class="hlt">distribution</span> of the hot <span class="hlt">gas</span>-to -metal heat transfer coefficient, and of the effect of changing the thermal conductivity of the blade metal for a constant cross sectional area blade with two quarter inch diameter coolant passages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930062532&hterms=blunt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dblunt','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930062532&hterms=blunt&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dblunt"><span>Convective heat-transfer rate <span class="hlt">distributions</span> over a 140 deg blunt cone at hypersonic speeds in different <span class="hlt">gas</span> environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stewart, David A.; Chen, Y. K.</p> <p>1993-01-01</p> <p>Experiments were conducted in air, CO2, and CO2-argon <span class="hlt">gas</span> mixtures to obtain heating <span class="hlt">distribution</span> data over a 140 deg blunt cone with various corner radii. The effect of corner radius on the heating <span class="hlt">distribution</span> over the forebody of the cone was included in the investigation. These experiments provide data for validation of two-dimensional axisymmetric and three-dimensional Navier-Stokes solutions. Heating <span class="hlt">distribution</span> data and measured bow shock wave stand-off distances for 0 deg angle of attack were compared with predicted values using a two-dimensional axisymmetric Navier-Stokes code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27018654','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27018654"><span>Across-shelf <span class="hlt">distribution</span> of blue mussel larvae in the northern Gulf of <span class="hlt">Maine</span>: consequences for population connectivity and a species range boundary.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yund, Philip O; Tilburg, Charles E; McCartney, Michael A</p> <p>2015-12-01</p> <p>Studies of population connectivity have largely focused on along-shelf, as opposed to across-shelf, processes. We hypothesized that a discontinuity in across-shelf mixing caused by the divergence of the Eastern <span class="hlt">Maine</span> Coastal Current (EMCC) from shore acts as an ecological barrier to the supply of mussel larvae to the coast. Existing data on the relative abundance of two congeneric blue mussels, Mytilus edulis and M. trossulus, were analysed to quantify the association of M. trossulus with the colder temperature signal of the EMCC and generate larval <span class="hlt">distribution</span> predictions. We then sampled the across-shelf <span class="hlt">distribution</span> of larvae along two transects during 2011. Larvae were identified using restriction digests of PCR amplicons from the mitochondrial 16S rDNA. Mytilus edulis larvae were consistently abundant on either the inshore and offshore transect ends, but not homogeneously <span class="hlt">distributed</span> across the shelf, while M. trossulus larvae were less common throughout the study area. The divergence of the EMCC from shore appears to create a break in the connectivity of M. edulis populations by isolating those inshore of the EMCC from upstream larval sources. Across-shelf transport processes can thus produce connectivity patterns that would not be predicted solely on the basis of along-shelf processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22683949','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22683949"><span>Characterization of industrial waste from a natural <span class="hlt">gas</span> <span class="hlt">distribution</span> company and management strategies: a case study of the East Azerbaijan <span class="hlt">Gas</span> Company (Iran).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Taghipour, Hassan; Aslhashemi, Ahmad; Assadi, Mohammad; Khodaei, Firoz; Mardangahi, Baharak; Mosaferi, Mohammad; Roshani, Babak</p> <p>2012-10-01</p> <p>Although a fundamental prerequisite for the successful implementation of any waste management plan is the availability of sufficient and accurate data, there are few available studies regarding the characterization and management of <span class="hlt">gas</span> <span class="hlt">distribution</span> company waste (GDCW). This study aimed to characterize the industrial waste generated by the East Azerbaijan <span class="hlt">Gas</span> <span class="hlt">Distribution</span> Company (EAGDC) and to present environmental management strategies. The EAGDC serves 57 cities and 821 villages with a total population of more than 2.5 million as well as numerous industrial units. The methodology of this study was based on a checklist of data collected from each zone of the company, site visits (observation), and quantity and quality analysis according to the formal data available from different zones. The results indicate that more than 35 different kinds of industrial solid waste are generated in different industrial installations. The most important types of generated waste include empty barrels (including mercaptans, diesel fuel, deionized waters and oil), faulty <span class="hlt">gas</span> meters and regulators, a variety of industrial oils, sleeves, filter elements and faulty pipes, valves and fittings. The results indicated that, currently, GDCW is generally handled and disposed of with domestic waste, deposited in companies' installation yards and stores or, sometimes, recycled through non-scientific approaches that can create health risks to the public and the environment, even though most of the GDCW was determined to be recyclable or reusable materials. This study concludes that <span class="hlt">gas</span> <span class="hlt">distribution</span> companies must pay more attention to source reduction, recycling and reusing of waste to preserve natural resources, landfill space and the environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27617793','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27617793"><span>Sensitive determination of THC and <span class="hlt">main</span> metabolites in human plasma by means of microextraction in packed sorbent and <span class="hlt">gas</span> chromatography-tandem mass spectrometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rosado, T; Fernandes, L; Barroso, M; Gallardo, E</p> <p>2017-02-01</p> <p>Cannabis is one of the most available and consumed illicit drug in the world and its identification and quantification in biological specimens can be a challenge given its low concentrations in body fluids. The present work describes a fast and fully validated procedure for the simultaneous detection and quantification of ▵(9)-tetrahydrocannabinol (▵(9_)THC) and its two <span class="hlt">main</span> metabolites 11-hydroxy ▵(9_)tetrahydrocannabinol (11-OH-THC) and 11-nor-9-carboxy-▵(9)- tetrahydrocannbinol (THC-COOH) in plasma samples using microextraction by packed sorbent (MEPS) and <span class="hlt">gas</span> chromatography-tandem mass spectrometry (GC-MS/MS). A small plasma volume (0.25mL) pre-diluted (1:20), was extracted with MEPS M1 sorbent as follows: conditioning (4 cycles of 250μL methanol and 4 cycles of 250μL 0.1% formic acid in water); sample load (26 cycles of 250μL); wash (100μL of 3% acetic acid in water followed by 100μL 5% methanol in water); and elution (6 cycles of 100μL of 10% ammonium hydroxide in methanol). The procedure allowed the quantification of all analytes in the range of 0.1-30ng/mL. Recoveries ranged from 53 to 78% (THC), 57 to 66% (11-OH-THC) and 62 to 65% (THC-COOH), allowing the limits of detection and quantification to be set at 0.1ng/mL for all compounds. Intra-day precision and accuracy revealed coefficients of variation (CVs) lower than 10% at the studied concentrations, with a mean relative error within±9%, while inter-day precision and accuracy showed CVs lower than 15% for all analytes at the tested concentrations, with an inaccuracy within±8%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.453.2533M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.453.2533M"><span>Searching for <span class="hlt">gas</span> giant planets on Solar system scales - a NACO/APP L'-band survey of A- and F-type <span class="hlt">main</span>-sequence stars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meshkat, T.; Kenworthy, M. A.; Reggiani, M.; Quanz, S. P.; Mamajek, E. E.; Meyer, M. R.</p> <p>2015-11-01</p> <p>We report the results of a direct imaging survey of A- and F-type <span class="hlt">main</span>-sequence stars searching for giant planets. A/F stars are often the targets of surveys, as they are thought to have more massive giant planets relative to solar-type stars. However, most imaging is only sensitive to orbital separations >30 au, where it has been demonstrated that giant planets are rare. In this survey, we take advantage of the high-contrast capabilities of the Apodizing Phase Plate coronagraph on NACO at the Very Large Telescope. Combined with optimized principal component analysis post-processing, we are sensitive to planetary-mass companions (2-12 MJup) at Solar system scales (≤30 au). We obtained data on 13 stars in the L' band and detected one new companion as part of this survey: an M6.0 ± 0.5 dwarf companion around HD 984. We re-detect low-mass companions around HD 12894 and HD 20385, both reported shortly after the completion of this survey. We use Monte Carlo simulations to determine new constraints on the low-mass (<80 MJup) companion frequency, as a function of mass and separation. Assuming solar-type planet mass and separation <span class="hlt">distributions</span>, normalized to the planet frequency appropriate for A-stars, and the observed companion mass-ratio <span class="hlt">distribution</span> for stellar companions extrapolated to planetary masses, we derive a truncation radius for the planetary mass companion surface density of <135 au at 95 per cent confidence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JTePh..60..376M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JTePh..60..376M"><span>Simulation of the electric field <span class="hlt">distribution</span> in the electrode system of a device forming a high-voltage <span class="hlt">gas</span> discharge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Markushin, M. A.; Kolpakov, V. A.; Krichevskii, S. V.; Kolpakov, A. I.</p> <p>2015-03-01</p> <p>We propose a model of the electric field <span class="hlt">distribution</span> in the electrode system of a <span class="hlt">gas</span>-discharge device. The possibility of application the method of conformal mapping of a function of a complex variable for describing analytically the form of the <span class="hlt">distribution</span> of equipotential lines of the field in the region of the circular orifice in the anode of the <span class="hlt">gas</span> discharge device is demonstrated. The method for obtaining a system of parametric equations for determining the equipotential lines and field lines is described. We obtain the theoretical maps of the electric field <span class="hlt">distribution</span>, which make it possible to determine their relation with the electrophysical parameters of the electrode system of the device.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10763233','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10763233"><span><span class="hlt">Gas</span> chromatographic simulated distillation-mass spectrometry for the determination of the boiling point <span class="hlt">distributions</span> of crude oils</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roussis; Fitzgerald</p> <p>2000-04-01</p> <p>The coupling of <span class="hlt">gas</span> chromatographic simulated distillation with mass spectrometry for the determination of the distillation profiles of crude oils is reported. The method provides the boiling point <span class="hlt">distributions</span> of both weight and volume percent amounts. The weight percent <span class="hlt">distribution</span> is obtained from the measured total ion current signal. The total ion current signal is converted to weight percent amount by calibration with a reference crude oil of a known distillation profile. Knowledge of the chemical composition of the crude oil across the boiling range permits the determination of the volume percent <span class="hlt">distribution</span>. The long-term repeatability is equivalent to or better than the short-term repeatability of the currently available American Society for Testing and Materials (ASTM) <span class="hlt">gas</span> chromatographic method for simulated distillation. Results obtained by the mass spectrometric method are in very good agreement with results obtained by conventional methods of physical distillation. The compositional information supplied by the method can be used to extensively characterize crude oils.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5098102','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5098102"><span>Spatiotemporal <span class="hlt">Distribution</span> and Assemblages of Fishes below the Lowermost Dam in Protected Reach in the Yangtze River <span class="hlt">Main</span> Stream: Implications for River Management</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Li, Junyi; Zhang, Hui; Lin, Danqing; Wu, Jinming; Wang, Chengyou; Xie, Xuan</p> <p>2016-01-01</p> <p>Now more and more ecologists concern about the impacts of dam construction on fish. However, studies of fishes downstream Gezhouba Dam were rarely reported except Chinese sturgeon (Acipenser sinensis Gray). In this study, catch investigations and five hydroacoustic detections were completed from 2015 to 2016 to understand the <span class="hlt">distribution</span>, size, and categories of fishes and their relationship with the environmental factors below Gezhouba Dam in protected reach in the Yangtze River <span class="hlt">main</span> stream. Results showed significant differences in fish <span class="hlt">distribution</span> and TS (target strength) between wet and flood seasons. Mean TS in five hydroacoustic detections were −59.98 dB, −54.70 dB, −56.16 dB, −57.90 dB, and −59.17 dB, respectively, and dominant fish species are Coreius guichenoti (Bleeker), Siniperca chuatsi (Basilewsky), and Pelteobagrus vachelli (Richardson). In the longitudinal direction, fish preferred to stay in some specific sections like reaches 2, 4, 7, 8, 11, and 16. Since hydrology factors change greatly in different seasons, environmental characteristics vary along the reaches, and human activities play an important role in the fish behavior, it is concluded that great cross-season changes in hydrology lead to the differences in TS and fish assemblages and that geography characteristics, especially channel geography, together with human activities influence fish longitudinal <span class="hlt">distribution</span>. This finding provides basic knowledge of spatiotemporal <span class="hlt">distribution</span> and assemblages of fishes in the extended reaches downstream Gezhouba Dam. In addition, it offers implications for river management. It could also serve as reference of future research on fish habitat. PMID:27843943</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27843943','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27843943"><span>Spatiotemporal <span class="hlt">Distribution</span> and Assemblages of Fishes below the Lowermost Dam in Protected Reach in the Yangtze River <span class="hlt">Main</span> Stream: Implications for River Management.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Junyi; Zhang, Hui; Lin, Danqing; Wu, Jinming; Wang, Chengyou; Xie, Xuan; Wei, Qiwei</p> <p>2016-01-01</p> <p>Now more and more ecologists concern about the impacts of dam construction on fish. However, studies of fishes downstream Gezhouba Dam were rarely reported except Chinese sturgeon (Acipenser sinensis Gray). In this study, catch investigations and five hydroacoustic detections were completed from 2015 to 2016 to understand the <span class="hlt">distribution</span>, size, and categories of fishes and their relationship with the environmental factors below Gezhouba Dam in protected reach in the Yangtze River <span class="hlt">main</span> stream. Results showed significant differences in fish <span class="hlt">distribution</span> and TS (target strength) between wet and flood seasons. Mean TS in five hydroacoustic detections were -59.98 dB, -54.70 dB, -56.16 dB, -57.90 dB, and -59.17 dB, respectively, and dominant fish species are Coreius guichenoti (Bleeker), Siniperca chuatsi (Basilewsky), and Pelteobagrus vachelli (Richardson). In the longitudinal direction, fish preferred to stay in some specific sections like reaches 2, 4, 7, 8, 11, and 16. Since hydrology factors change greatly in different seasons, environmental characteristics vary along the reaches, and human activities play an important role in the fish behavior, it is concluded that great cross-season changes in hydrology lead to the differences in TS and fish assemblages and that geography characteristics, especially channel geography, together with human activities influence fish longitudinal <span class="hlt">distribution</span>. This finding provides basic knowledge of spatiotemporal <span class="hlt">distribution</span> and assemblages of fishes in the extended reaches downstream Gezhouba Dam. In addition, it offers implications for river management. It could also serve as reference of future research on fish habitat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS52B..07P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS52B..07P"><span>Role of in situ organic matter degradation and fluid flow in the global <span class="hlt">gas</span> hydrate <span class="hlt">distribution</span>: application of general functions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pinero, E.; Hensen, C.; Marquardt, M.; Haeckel, M.; Wallmann, K. J.</p> <p>2010-12-01</p> <p>During the last decades several estimates of the global <span class="hlt">gas</span> hydrate budget have been published. The published results range by several orders of magnitude and thus, the total <span class="hlt">gas</span> hydrate inventory is still poorly known. In order to elucidate the global <span class="hlt">gas</span> hydrate amount we applied a recently published transfer function that calculates the amount of <span class="hlt">gas</span> hydrate produced by in situ generated methane through organic matter degradation (Marquardt et al., accepted). The transfer function was derived from a large set of systematic runs of a numerical diagenetic model (Wallmann et al., 2006) covering a wide range of environmental conditions that are typical for the continental margins. The transfer function only includes two variables: the accumulation rate of particulate organic carbon and the thickness of the <span class="hlt">gas</span> hydrate stability zone. We tested various approaches to calculate both parameters on the global scale. The global grids used include seafloor bathymetry, TOC input, organic rain rate, bottom water temperature, geothermal gradient estimated from heat flow, sediment thickness, and age of the oceanic crust. The results obtained lead to the conclusion that only minor amounts of <span class="hlt">gas</span> hydrates (<10 Gt of C) are formed by in situ methane production. An extended function considering fluid flow was developed applying the same transport-reaction model. The resulting global <span class="hlt">distribution</span> map gives a total inventory of <span class="hlt">gas</span> hydrate ranging from 400 to 2500 Gt of C. So far, some of our calculations are slightly lower than previously published results (e.g. Archer et al., 2009) and suggest that only <2 % of the global <span class="hlt">gas</span> hydrate budget forms from an autochthonous source of methane. The results presented here suggest that where <span class="hlt">gas</span> does not migrate into the <span class="hlt">gas</span> hydrate stability zone only minor negligible concentrations of <span class="hlt">gas</span> hydrate accumulate. References: Wallmann, K., Aloisi, G. Haeckel, M., Obzhirov, A., Pavlova, G., Tishchenko, P.: Kinetics of organic matter degradation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MNRAS.456.2406R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MNRAS.456.2406R"><span>The Carina Nebula and Gum 31 molecular complex - I. Molecular <span class="hlt">gas</span> <span class="hlt">distribution</span>, column densities, and dust temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rebolledo, David; Burton, Michael; Green, Anne; Braiding, Catherine; Molinari, Sergio; Wong, Graeme; Blackwell, Rebecca; Elia, Davide; Schisano, Eugenio</p> <p>2016-03-01</p> <p>We report high-resolution observations of the 12CO(1-0) and 13CO(1-0) molecular lines in the Carina Nebula and the Gum 31 region obtained with the 22-m Mopra telescope as part of The Mopra Southern Galactic Plane CO Survey. We cover 8 deg2 from l = 285° to 290°, and from b = -1.5° to +0.5°. The molecular <span class="hlt">gas</span> column density <span class="hlt">distributions</span> from both tracers have a similar range of values. By fitting a grey-body function to the observed infrared spectral energy <span class="hlt">distribution</span> from Herschel maps, we derive <span class="hlt">gas</span> column densities and dust temperatures. The <span class="hlt">gas</span> column density has values in the range from 6.3 × 1020 to 1.4 × 1023 cm-2, while the dust temperature has values in the range from 17 to 43 K. The <span class="hlt">gas</span> column density derived from the dust emission is approximately described by a lognormal function for a limited range of column densities. A high-column-density tail is clearly evident for the <span class="hlt">gas</span> column density <span class="hlt">distribution</span>, which appears to be a common feature in regions with active star formation. There are regional variations in the fraction of the mass recovered by the CO emission lines with respect to the total mass traced by the dust emission. These variations may be related to changes in the radiation field strength, variation of the atomic to molecular <span class="hlt">gas</span> fraction across the observed region, differences in the CO molecule abundance with respect to H2, and evolutionary stage differences of the molecular clouds that compose the Carina Nebula-Gum 31 complex.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS23F..01J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS23F..01J"><span>Joint Interpretation of Electromagnetic and Seismic Data to Determine <span class="hlt">Gas</span> and Methane Hydrate <span class="hlt">Distribution</span> within the Nyegga CNE03 Seep.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jegen, M. D.; Hölz, S.; Cukur, D.; Sommer, M.; Attias, E.; Weitemeyer, K.; Berndt, C.</p> <p>2014-12-01</p> <p>The presence of the Nyegga pockmark field within the <span class="hlt">gas</span> hydrate stability field on the Norwegian continental slope points to possible methane release through cold seeps. It is, however, not clear how the methane may migrate through the still existing hydrate stability zone as the <span class="hlt">gas</span> should form new hydrate further up in the section. In an effort to better understand the physical processes and quantify the hydrate/<span class="hlt">gas</span> <span class="hlt">distribution</span> in the area, GEOMAR and the University of Southampton collected different types of electromagnetic data sets with different depth ranges and resolution in a region, which has been extensively covered by seismic investigation. The presence of hydrate within seafloor sediments causes an increase in both the bulk modulus, and hence the seismic velocity, and in the electrical resistivity. The presence of <span class="hlt">gas</span> decreases seismic velocity but increases electrical resistivity. Both seismic and controlled source electromagnetic methods can and have been used to estimate hydrate and <span class="hlt">gas</span> content. Since seismic velocity and the electrical resistivity are sensitive also to a range of other parameters such as lithology, porosity and pore fluid salinity, single rock property parameter investigations are hampered by many uncertainties. However, since the sensitivities are different for the two properties, determination of both velocity and resistivity for the same volume of sea bed provides a powerful tool for distinguishing the contribution of hydrate or <span class="hlt">gas</span> from that of other parameters. In this work we report on a new type of 3D electromagnetic high resolution tomography experiment which was focused on the CNE03 chimney in the centre of the region. The data indicates the presence of a highly resistive zone, where seismic travel time tomography has shown the presence of <span class="hlt">gas</span> hydrates within the chimney. The <span class="hlt">distribution</span> of methane hydrate concentrations are derived based on a joint interpretation of seismic velocity and electrical resistivities.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6678803','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6678803"><span>Evaluation of cased and uncased <span class="hlt">gas</span> <span class="hlt">distribution</span> and transmission piping under railroads and highways, Phase 2. Annual report, November 1987</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>O'Rourke, T.D.; Stewart, H.E.; Ingraffea, A.R.; Nyman, K.J.; Crossley, C.W.</p> <p>1987-11-01</p> <p>A comprehensive methodology is being developed for evaluating stresses in natural <span class="hlt">gas</span> pipelines at railroad and highway crossings. The methodology accounts for soil-structure interaction and the three-dimensional <span class="hlt">distribution</span> of pipeline stresses. The methodology involves delineating field loads and geometries through detailed site observations and discussions with industry personnel, and using computer graphics to analyze pipeline stresses under the complex three-dimensional conditions which prevail in the field. Field experiments will be performed to substantiate the predicted pipeline stresses at railroad crossings. Guidelines will be developed for pipeline crossings acceptable to representatives of <span class="hlt">gas</span>, railroad, and highway industries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title49-vol3/pdf/CFR-2014-title49-vol3-sec192-1005.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title49-vol3/pdf/CFR-2014-title49-vol3-sec192-1005.pdf"><span>49 CFR 192.1005 - What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-10-01</p> <p>... 49 Transportation 3 2014-10-01 2014-10-01 false What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol3/pdf/CFR-2011-title49-vol3-sec192-1005.pdf','CFR2011'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2011-title49-vol3/pdf/CFR-2011-title49-vol3-sec192-1005.pdf"><span>49 CFR 192.1005 - What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2011&page.go=Go">Code of Federal Regulations, 2011 CFR</a></p> <p></p> <p>2011-10-01</p> <p>... 49 Transportation 3 2011-10-01 2011-10-01 false What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2012-title49-vol3/pdf/CFR-2012-title49-vol3-sec192-1005.pdf','CFR2012'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2012-title49-vol3/pdf/CFR-2012-title49-vol3-sec192-1005.pdf"><span>49 CFR 192.1005 - What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2012&page.go=Go">Code of Federal Regulations, 2012 CFR</a></p> <p></p> <p>2012-10-01</p> <p>... 49 Transportation 3 2012-10-01 2012-10-01 false What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title49-vol3/pdf/CFR-2013-title49-vol3-sec192-1005.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title49-vol3/pdf/CFR-2013-title49-vol3-sec192-1005.pdf"><span>49 CFR 192.1005 - What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-10-01</p> <p>... 49 Transportation 3 2013-10-01 2013-10-01 false What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title49-vol3/pdf/CFR-2010-title49-vol3-sec192-1005.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title49-vol3/pdf/CFR-2010-title49-vol3-sec192-1005.pdf"><span>49 CFR 192.1005 - What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... 49 Transportation 3 2010-10-01 2010-10-01 false What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do to implement this subpart? 192.1005 Section 192.1005...) § 192.1005 What must a <span class="hlt">gas</span> <span class="hlt">distribution</span> operator (other than a master meter or small LPG operator) do...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23090054','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23090054"><span>Activity, <span class="hlt">distribution</span>, and abundance of methane-oxidizing bacteria in the near surface soils of onshore oil and <span class="hlt">gas</span> fields.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Kewei; Tang, Yuping; Ren, Chun; Zhao, Kebin; Wang, Wanmeng; Sun, Yongge</p> <p>2013-09-01</p> <p>Methane-oxidizing bacteria (MOB) have long been used as an important biological indicator for oil and <span class="hlt">gas</span> prospecting, but the ecological characteristics of MOB in hydrocarbon microseep systems are still poorly understood. In this study, the activity, <span class="hlt">distribution</span>, and abundance of aerobic methanotrophic communities in the surface soils underlying an oil and <span class="hlt">gas</span> field were investigated using biogeochemical and molecular ecological techniques. Measurements of potential methane oxidation rates and pmoA gene copy numbers showed that soils inside an oil and <span class="hlt">gas</span> field are hot spots of methane oxidation and MOB abundance. Correspondingly, terminal restriction fragment length polymorphism analyses in combination with cloning and sequencing of pmoA genes also revealed considerable differences in the methanotrophic community composition between oil and <span class="hlt">gas</span> fields and the surrounding soils. Principal component analysis ordination furthermore indicated a coincidence between elevated CH4 oxidation activity and the methanotrophic community structure with type I methanotrophic Methylococcus and Methylobacter, in particular, as indicator species of oil and <span class="hlt">gas</span> fields. Collectively, our results show that trace methane migrated from oil and <span class="hlt">gas</span> reservoirs can considerably influence not only the quantity but also the structure of the methanotrophic community.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008A%26A...487..951K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008A%26A...487..951K"><span>Global properties of the H I <span class="hlt">distribution</span> in the outer Milky Way. Planar and extra-planar <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kalberla, P. M. W.; Dedes, L.</p> <p>2008-09-01</p> <p>Context: The determination of the global structure of the planar and extra-planar Milky Way H I disk depends critically on a reliable database but also on reasonable assumptions about the shape of the Milky Way rotation curve. Aims: We derive the 3D H I volume density <span class="hlt">distribution</span> for the Galactic disk out to R ˜ 60 kpc. Methods: Our analysis is based on parameters for the warp and rotation curve derived previously. The data are taken from the Leiden/Argentine/Bonn all sky 21 cm line survey. Results: The Milky Way H I disk is significantly warped but shows a coherent structure out to R ˜ 35 kpc. The radial surface density <span class="hlt">distribution</span>, the densities in the middle of the warped plane, and the H I scale heights all follow exponential relations. The radial scale length for the surface density <span class="hlt">distribution</span> of the H I disk is 3.75 kpc. <span class="hlt">Gas</span> at the outskirts for 40 ⪉ R ⪉ 60 kpc is described best by a <span class="hlt">distribution</span> with an exponential radial scale length of 7.5 kpc and a velocity dispersion of 74 km s-1. Such a highly turbulent medium fits also well with the average shape of the high velocity profile wings observed at high latitudes. The turbulent pressure gradient of such extra-planar <span class="hlt">gas</span> is on average in balance with the gravitational forces. About 10% of the Milky Way H I <span class="hlt">gas</span> is in this state. The large scale H I <span class="hlt">distribution</span> is lopsided; for R ⪆ 15 kpc there is more <span class="hlt">gas</span> in the south. The H I flaring indicates that this asymmetry is caused by a dark matter wake, located at R ˜ 25 kpc in direction of the Magellanic System. Conclusions: The H I disk is made up of two major components. Most prominent is the normal H I disk which can be traced to R ˜ 35 kpc. This is surrounded by a patchy <span class="hlt">distribution</span> of highly turbulent <span class="hlt">gas</span> reaching large scale heights but also large radial distances. At the position of the Sun the exponential scale height in the z direction is 3.9 kpc. This component resembles the anomalous <span class="hlt">gas</span> discovered previously in some galaxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28119037','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28119037"><span>Mitigation of methane emissions in a pilot-scale biocover system at the AV Miljø Landfill, Denmark: 1. System design and <span class="hlt">gas</span> <span class="hlt">distribution</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cassini, Filippo; Scheutz, Charlotte; Skov, Bent H; Mou, Zishen; Kjeldsen, Peter</p> <p>2017-01-21</p> <p>Greenhouse <span class="hlt">gas</span> mitigation at landfills by methane oxidation in engineered biocover systems is believed to be a cost effective technology, but so far a full quantitative evaluation of the efficiency of the technology in full scale has only been carried out in a few cases. A third generation semi-passive biocover system was constructed at the AV Miljø Landfill, Denmark. The biocover system was fed by landfill <span class="hlt">gas</span> pumped out of three leachate collection wells. An innovative <span class="hlt">gas</span> <span class="hlt">distribution</span> system was used to overcome the commonly observed surface emission hot spot areas resulting from an uneven <span class="hlt">gas</span> <span class="hlt">distribution</span> to the active methane oxidation layer, leading to areas with methane overloading. Performed screening of methane and carbon dioxide surface concentrations, as well as flux measurement using a flux chamber at the surface of the biocover, showed homogenous <span class="hlt">distributions</span> indicating an even <span class="hlt">gas</span> <span class="hlt">distribution</span>. This was supported by results from a tracer <span class="hlt">gas</span> test where the compound HFC-134a was added to the <span class="hlt">gas</span> inlet over an adequately long time period to obtain tracer <span class="hlt">gas</span> stationarity in the whole biocover system. Studies of the tracer <span class="hlt">gas</span> movement within the biocover system showed a very even <span class="hlt">gas</span> <span class="hlt">distribution</span> in <span class="hlt">gas</span> probes installed in the <span class="hlt">gas</span> <span class="hlt">distribution</span> layer. Also the flux of tracer <span class="hlt">gas</span> out of the biocover surface, as measured by flux chamber technique, showed a spatially even <span class="hlt">distribution</span>. Installed probes logging the temperature and moisture content of the methane oxidation layer at different depths showed elevated temperatures in the layer with temperature differences to the ambient temperature in the range of 25-50°C at the deepest measuring point due to the microbial processes occurring in the layer. The moisture measurements showed that infiltrating precipitation was efficiently drained away from the methane oxidation layer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014acm..conf..234J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014acm..conf..234J"><span>Both size-frequency <span class="hlt">distribution</span> and sub-populations of the <span class="hlt">main</span>-belt asteroid population are consistent with YORP-induced rotational fission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jacobson, S.; Scheeres, D.; Rossi, A.; Marzari, F.; Davis, D.</p> <p>2014-07-01</p> <p>From the results of a comprehensive asteroid-population-evolution model, we conclude that the YORP-induced rotational-fission hypothesis has strong repercussions for the small size end of the <span class="hlt">main</span>-belt asteroid size-frequency <span class="hlt">distribution</span> and is consistent with observed asteroid-population statistics and with the observed sub-populations of binary asteroids, asteroid pairs and contact binaries. The foundation of this model is the asteroid-rotation model of Marzari et al. (2011) and Rossi et al. (2009), which incorporates both the YORP effect and collisional evolution. This work adds to that model the rotational fission hypothesis (i.e. when the rotation rate exceeds a critical value, erosion and binary formation occur; Scheeres 2007) and binary-asteroid evolution (Jacobson & Scheeres, 2011). The YORP-effect timescale for large asteroids with diameters D > ˜ 6 km is longer than the collision timescale in the <span class="hlt">main</span> belt, thus the frequency of large asteroids is determined by a collisional equilibrium (e.g. Bottke 2005), but for small asteroids with diameters D < ˜ 6 km, the asteroid-population evolution model confirms that YORP-induced rotational fission destroys small asteroids more frequently than collisions. Therefore, the frequency of these small asteroids is determined by an equilibrium between the creation of new asteroids out of the impact debris of larger asteroids and the destruction of these asteroids by YORP-induced rotational fission. By introducing a new source of destruction that varies strongly with size, YORP-induced rotational fission alters the slope of the size-frequency <span class="hlt">distribution</span>. Using the outputs of the asteroid-population evolution model and a 1-D collision evolution model, we can generate this new size-frequency <span class="hlt">distribution</span> and it matches the change in slope observed by the SKADS survey (Gladman 2009). This agreement is achieved with both an accretional power-law or a truncated ''Asteroids were Born Big'' size-frequency <span class="hlt">distribution</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27463368','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27463368"><span>Mass Spectrometric Imaging of Wheat (Triticum spp.) and Barley (Hordeum vulgare L.) Cultivars: <span class="hlt">Distribution</span> of Major Cell Wall Polysaccharides According to Their <span class="hlt">Main</span> Structural Features.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Veličković, Dušan; Saulnier, Luc; Lhomme, Margot; Damond, Aurélie; Guillon, Fabienne; Rogniaux, Hélène</p> <p>2016-08-17</p> <p>Arabinoxylans (AX) and (1→3),(1→4)-β-glucans (BG) are the <span class="hlt">main</span> components of cereal cell walls and influence many aspects of their end uses. Important variations in the composition and structure of these polysaccharides have been reported among cereals and cultivars of a given species. In this work, the spatial <span class="hlt">distribution</span> of AX and BG in the endosperm of mature grains was established for nine wheat varieties and eight barley varieties using enzymatically assisted mass spectrometry imaging (MSI). Important structural features of the AX and BG polymers that were previously shown to influence their physicochemical properties were assessed. Differences in the <span class="hlt">distribution</span> of AX and BG structures were observed, both within the endosperm of a given cultivar and between wheat and barley cultivars. This study provides a unique picture of the structural heterogeneity of AX and BG polysaccharides at the scale of the whole endosperm in a series of wheat and barley cultivars. Thus, it can participate meaningfully in a strategy aiming at understanding the structure-function relationships of these two polymers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17298565','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17298565"><span>Spatial and non-spatial risk factors associated with cage-level <span class="hlt">distribution</span> of infectious salmon anaemia at three Atlantic salmon, Salmo salar L., farms in <span class="hlt">Maine</span>, USA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gustafson, L; Ellis, S; Robinson, T; Marenghi, F; Merrill, P; Hawkins, L; Giray, C; Wagner, B</p> <p>2007-02-01</p> <p>The <span class="hlt">distribution</span> of infectious salmon anaemia (ISA) was examined among 80 cages from three Atlantic salmon grow-out farms in <span class="hlt">Maine</span>, USA that were stocked with smolts from a single hatchery. Cage-level disease was broadly defined as one or more moribund fish testing positive for infectious salmon anaemia virus (ISAV) by RT-PCR and a second confirmatory test (IFAT, culture or genotype sequence). Spatio-temporal and cage-level risks were explored using logistic regression and survival analysis. Non-spatial risk factors associated with ISA, or shortened survival time to disease, included increased predation, trucking company choice for smolt transfers, a finely-sedimented benthic substrate, and smaller average size of smolts at stocking. Univariable analysis identified the time-dependent spatial factor 'adjacency to newly infected cages' to be predictive of new infection in neighbouring cages 11-12 weeks later. However, none of the spatial factors, or their lags retained relevance in multiple-variable models. The results suggest a diffuse <span class="hlt">distribution</span> of virus exposure throughout infected sites, with host-susceptibility factors probably influencing disease manifestation in individual cages. The narrow focus of the current study may limit application of the findings to other sites and year-classes. However, these data support the relevance of husbandry efforts to optimize fish health in regions affected by ISAV.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20674659','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20674659"><span>Peculiarities of <span class="hlt">distribution</span> of <span class="hlt">gas</span>-dynamic manifestations in mines of the Kuznetsk coal basin by days of the weekly cycle</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Oparin, V.N.; Ludzish, V.S.; Kulakov, G.I.; Rudakov, V.A.</p> <p>2005-04-01</p> <p>The peculiarities of the origin of <span class="hlt">gas</span>-dynamic events (rock, coal, and <span class="hlt">gas</span> outbursts, methane ignition) in the Kuznetsk Basin mines in 1988 - 2004 are analyzed. A review is presented for information on recent accident and injury rate caused by disastrous <span class="hlt">gas</span>-dynamic manifestations. The effect of bimodal frequency <span class="hlt">distribution</span> of <span class="hlt">gas</span>-dynamic events generated by explosion and burning of methane is revealed within a generalized weekly cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810015066','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810015066"><span>Evaluation of <span class="hlt">distributed</span> <span class="hlt">gas</span> cooling of pressurized PAFC for utility power generation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farooque, M.; Hooper, M.; Maru, H.</p> <p>1981-01-01</p> <p>A proof-of-concept test for a <span class="hlt">gas</span>-cooled pressurized phosphoric acid fuel cell is described. After initial feasibility studies in short stacks, two 10 kW stacks are tested. Progress includes: (1) completion of design of the test stations with a recirculating <span class="hlt">gas</span> cooling loop; (2) atmospheric testing of the baseline stack.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19710000395','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19710000395"><span>Steady temperature and density <span class="hlt">distributions</span> in a <span class="hlt">gas</span> containing heat sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Davison, H. W.</p> <p>1971-01-01</p> <p>Computer program, STADDIG, is based on steady state, one dimensional heat transfer calculation using cylindrical coordinates. Program allows for conduction across <span class="hlt">gas</span> and container walls. Heat is dissipated from walls by forced convection cooling with incompressible coolant. Heat sources are included in coolant, <span class="hlt">gas</span>, and walls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGeo...12.5161E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGeo...12.5161E"><span>The greenhouse <span class="hlt">gas</span> balance of a drained fen peatland is <span class="hlt">mainly</span> controlled by land-use rather than soil organic carbon content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eickenscheidt, T.; Heinichen, J.; Drösler, M.</p> <p>2015-09-01</p> <p>Drained organic soils are considered to be hotspots for greenhouse <span class="hlt">gas</span> (GHG) emissions. Arable lands and intensively used grasslands, in particular, have been regarded as the <span class="hlt">main</span> producers of carbon dioxide (CO2) and nitrous oxide (N2O). However, GHG balances of former peatlands and associated organic soils not considered to be peatland according to the definition of the Intergovernmental Panel on Climate Change (IPCC) have not been investigated so far. Therefore, our study addressed the question to what extent the soil organic carbon (SOC) content affects the GHG release of drained organic soils under two different land-use types (arable land and intensively used grassland). Both land-use types were established on a Mollic Gleysol (labeled Cmedium) as well as on a Sapric Histosol (labeled Chigh). The two soil types differed significantly in their SOC contents in the topsoil (Cmedium: 9.4-10.9 % SOC; Chigh: 16.1-17.2 % SOC). We determined GHG fluxes over a period of 1 or 2 years in case of N2O or methane (CH4) and CO2, respectively. The daily and annual net ecosystem exchange (NEE) of CO2 was determined by measuring NEE and the ecosystem respiration (RECO) with the closed dynamic chamber technique and by modeling the RECO and the gross primary production (GPP). N2O and CH4 were measured with the static closed chamber technique. Estimated NEE of CO2 differed significantly between the two land-use types, with lower NEE values (-6 to 1707 g CO2-C m-2 yr-1) at the arable sites and higher values (1354 to 1823 g CO2-C m-2 yr-1) at the grassland sites. No effect on NEE was found regarding the SOC content. Significantly higher annual N2O exchange rates were observed at the arable sites (0.23-0.86 g N m-2 yr-1) than at the grassland sites (0.12-0.31 g N m-2 yr-1). Furthermore, N2O fluxes from the Chigh sites significantly exceeded those of the Cmedium sites. CH4 fluxes were found to be close to zero at all plots. Estimated global warming potential, calculated for a time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015BGD....12.5201E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015BGD....12.5201E"><span>The greenhouse <span class="hlt">gas</span> balance of a drained fen peatland is <span class="hlt">mainly</span> controlled by land-use rather than soil organic carbon content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eickenscheidt, T.; Heinichen, J.; Drösler, M.</p> <p>2015-04-01</p> <p>Drained organic soils are considered as hotspots for greenhouse <span class="hlt">gas</span> (GHG) emissions. Particularly arable lands and intensively used grasslands have been regarded as the <span class="hlt">main</span> producers of carbon dioxide (CO2) and nitrous oxide (N2O). However, GHG balances of former peatlands and associated organic soils not considered as peatland according to the definition of the Intergovernmental Panel on Climate Change (IPCC) have not been investigated so far. Therefore, our study addressed the question to what extent the soil organic carbon (SOC) content affects the GHG release of drained organic soils under two different land-use types (arable land and intensively used grassland). Both land-use types were established on a mollic Gleysol (named Cmedium) as well as on a sapric Histosol (named Chigh). The two soil types significantly differed in their SOC contents in the topsoil (Cmedium: 9.4-10.9% SOC; Chigh: 16.1-17.2% SOC). We determined GHG fluxes (CO2, N2O and methane (CH4)) over a period of 2 years. The daily and annual net ecosystem exchange (NEE) of CO2 was determined with the closed dynamic chamber technique and by modeling the ecosystem respiration (RECO) and the gross primary production (GPP). N2O and CH4 were determined by the close chamber technique. Estimated NEE of CO2 significantly differed between the two land-use types with lower NEE values (-6 to 1707 g CO2-C m-2 yr-1) at the arable sites and higher values (1354 to 1823 g CO2-C m-2 yr-1) at the grassland sites. No effect on NEE was found regarding the SOC content. Significantly higher annual N2O exchange rates were observed at the arable sites (0.23-0.86 g N m-2 yr-1) compared to the grassland sites (0.12-0.31 g N m-2 yr-1). Furthermore, N2O fluxes from the Chigh sites significantly exceeded those of the Cmedium sites. CH4 fluxes were found to be close to zero at all plots. Estimated global warming potential, calculated for a time horizon of 100 years (GWP100) revealed a very high release of GHGs from all plots</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/211664','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/211664"><span>Gamma densitometry tomography of <span class="hlt">gas</span> holdup spatial <span class="hlt">distribution</span> in industrial scale bubble columns</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shollenberger, K.A.; Torczynski, J.R.; Adkins, D.R.; O`Hern, T.J.; Jackson, N.B.</p> <p>1995-12-31</p> <p>Gamma-densitometry tomography (GDT) experiments have been performed to measure <span class="hlt">gas</span> holdup spatial variations in two bubble columns: a 0.19 m inside diameter Lucite column and a 0.48 m inside diameter stainless steel vessel. Air and water were used for the measurements. Horizontal scans at one vertical position in each column were made for several air flow rates. An axi-symmetric tomographic reconstruction algorithm based on the Abel transform has been used to calculate the time averaged <span class="hlt">gas</span> holdup radial variation. Integration of these profiles over the column cross section has yielded area-averaged <span class="hlt">gas</span> holdup results, which have been compared with volume-averaged <span class="hlt">gas</span> holdups determined from differential pressure measurements and from the rise in the air/water interface during <span class="hlt">gas</span> flow. The results agree reasonably well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AtmEn.106..467S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AtmEn.106..467S"><span>Application of the Junge- and Pankow-equation for estimating indoor <span class="hlt">gas</span>/particle <span class="hlt">distribution</span> and exposure to SVOCs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Salthammer, Tunga; Schripp, Tobias</p> <p>2015-04-01</p> <p>In the indoor environment, <span class="hlt">distribution</span> and dynamics of an organic compound between <span class="hlt">gas</span> phase, particle phase and settled dust must be known for estimating human exposure. This, however, requires a detailed understanding of the environmentally important compound parameters, their interrelation and of the algorithms for calculating partitioning coefficients. The parameters of major concern are: (I) saturation vapor pressure (PS) (of the subcooled liquid); (II) Henry's law constant (H); (III) octanol/water partition coefficient (KOW); (IV) octanol/air partition coefficient (KOA); (V) air/water partition coefficient (KAW) and (VI) settled dust properties like density and organic content. For most of the relevant compounds reliable experimental data are not available and calculated <span class="hlt">gas</span>/particle <span class="hlt">distributions</span> can widely differ due to the uncertainty in predicted Ps and KOA values. This is not a big problem if the target compound is of low (<10-6 Pa) or high (>10-2 Pa) volatility, but in the intermediate region even small changes in Ps or KOA will have a strong impact on the result. Moreover, the related physical processes might bear large uncertainties. The KOA value can only be used for particle absorption from the <span class="hlt">gas</span> phase if the organic portion of the particle or dust is high. The Junge- and Pankow-equation for calculating the <span class="hlt">gas</span>/particle <span class="hlt">distribution</span> coefficient KP do not consider the physical and chemical properties of the particle surface area. It is demonstrated by error propagation theory and Monte-Carlo simulations that parameter uncertainties from estimation methods for molecular properties and variations of indoor conditions might strongly influence the calculated <span class="hlt">distribution</span> behavior of compounds in the indoor environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS23F..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS23F..02M"><span>High-Resolution Seismic Definition of the <span class="hlt">Distribution</span> of <span class="hlt">Gas</span> in the West Svalbard Margin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Minshull, T. A.; Westbrook, G. K.; Marin-Moreno, H.; Marsset, B.; Ker, S.; Sarkar, S.; Vardy, M. E.; Henstock, T.</p> <p>2014-12-01</p> <p>The widespread presence of <span class="hlt">gas</span> beneath the seabed west of Svalbard is shown by negative-polarity high-amplitude reflectors (nephars), imaged in high-resolution near-surface and deep-towed seismic reflection data. The principal controls on the presence of <span class="hlt">gas</span> are the <span class="hlt">gas</span> hydrate stability zone (GHSZ), from which free <span class="hlt">gas</span> is generally excluded, and stratigraphic control of permeable layers. A widespread bottom-simulating reflector (BSR) beneath the lower-mid continental slope indicates <span class="hlt">gas</span> at the base of the GHSZ. The depth of the base of the GHSZ predicted by a numerical model that takes in to account variation in ocean temperature over the past two thousand years, is consistent with the depth of the BSR, even at its shallowest depth, where a steady-state model places base of the GHSZ shallower than the BSR. Similarly, farther up slope, where the BSR loses it coherency, the depths of the shallowest nephars are compatible with the predicted depth of the base of the GHSZ from the time-dependent model, but are about three times deeper than the predicted steady-state depth of the BSR. This approach to defining the limits of the GHSZ is not precise, as it depends upon the presence of <span class="hlt">gas</span>. In the shallow sediment sequence, which has a high proportion of glacigenic sediments, <span class="hlt">gas</span> is restricted to a smaller number of permeable units than in the contourite-dominated sequence farther down the continental slope. Where the seabed is shallower than the GHSZ, numerous plumes of methane <span class="hlt">gas</span> ascend from the seabed, and <span class="hlt">gas</span>, which has migrated up slope through dipping permeable layers, locally ponds beneath a thin veneer of unconformable glacial and post-glacial sediments on the continental shelf.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6532215','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6532215"><span>Algeria to use <span class="hlt">gas</span> to meet energy demands</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1986-12-01</p> <p>Sonelgaz, Algeria's natural <span class="hlt">gas</span> <span class="hlt">distribution</span> monopoly, plans to supply all major towns in the country with natural <span class="hlt">gas</span> for domestic energy demands by 1989. The utility uses copper tubing in residences and plastic pipe for <span class="hlt">distribution</span> <span class="hlt">mains</span> and services to the houses for new construction and conversion to natural <span class="hlt">gas</span> from LPG systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016OptEn..55g6107Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016OptEn..55g6107Z"><span>Reconstruction of combustion temperature and <span class="hlt">gas</span> concentration <span class="hlt">distributions</span> using line-of-sight tunable diode laser absorption spectroscopy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Zhirong; Sun, Pengshuai; Pang, Tao; Xia, Hua; Cui, Xiaojuan; Li, Zhe; Han, Luo; Wu, Bian; Wang, Yu; Sigrist, Markus W.; Dong, Fengzhong</p> <p>2016-07-01</p> <p>Spatial temperature and <span class="hlt">gas</span> concentration <span class="hlt">distributions</span> are crucial for combustion studies to characterize the combustion position and to evaluate the combustion regime and the released heat quantity. Optical computer tomography (CT) enables the reconstruction of temperature and <span class="hlt">gas</span> concentration fields in a flame on the basis of line-of-sight tunable diode laser absorption spectroscopy (LOS-TDLAS). A pair of H2O absorption lines at wavelengths 1395.51 and 1395.69 nm is selected. Temperature and H2O concentration <span class="hlt">distributions</span> for a flat flame furnace are calculated by superimposing two absorption peaks with a discrete algebraic iterative algorithm and a mathematical fitting algorithm. By comparison, direct absorption spectroscopy measurements agree well with the thermocouple measurements and yield a good correlation. The CT reconstruction data of different air-to-fuel ratio combustion conditions (incomplete combustion and full combustion) and three different types of burners (one, two, and three flat flame furnaces) demonstrate that TDLAS has the potential of short response time and enables real-time temperature and <span class="hlt">gas</span> concentration <span class="hlt">distribution</span> measurements for combustion diagnosis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.epa.gov/newsreleases/epa-and-dominion-cove-point-settle-violations-natural-gas-distribution-facility','PESTICIDES'); return false;" href="https://www.epa.gov/newsreleases/epa-and-dominion-cove-point-settle-violations-natural-gas-distribution-facility"><span>EPA and Dominion Cove Point Settle Violations at Natural <span class="hlt">Gas</span> <span class="hlt">Distribution</span> Facility in Maryland</span></a></p> <p><a target="_blank" href="http://www.epa.gov/pesticides/search.htm">EPA Pesticide Factsheets</a></p> <p></p> <p></p> <p>PHILADELPHIA (March 16, 2015) - Dominion Cove Point, LNG will pay a $365,000 civil penalty to settle alleged violations of federal environmental regulations involving unreported releases of ammonia into the air from its liquefied natural <span class="hlt">gas</span> distrib</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...579A..91W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...579A..91W"><span>ATLASGAL - Kinematic distances and the dense <span class="hlt">gas</span> mass <span class="hlt">distribution</span> of the inner Galaxy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wienen, M.; Wyrowski, F.; Menten, K. M.; Urquhart, J. S.; Csengeri, T.; Walmsley, C. M.; Bontemps, S.; Russeil, D.; Bronfman, L.; Koribalski, B. S.; Schuller, F.</p> <p>2015-07-01</p> <p>Context. The formation of high mass stars and clusters occurs in giant molecular clouds. Objects in evolved stages of massive star formation such as protostars, hot molecular cores, and ultracompact HII regions have been studied in more detail than earlier, colder objects. Further progress thus requires the analysis of the time before massive protostellar objects can be probed by their infrared emission. With this in mind, the APEX Telescope Large Area Survey of the whole inner Galactic plane at 870 μm (ATLASGAL) has been carried out to provide a global view of cold dust and star formation at submillimetre wavelengths. Aims: We derive kinematic distances to a large sample of massive cold dust clumps from their measured line velocities. We estimate masses and sizes of ATLASGAL sources, for which the kinematic distance ambiguity is resolved. Methods: The ATLASGAL sample is divided into groups of sources, which are located close together, mostly within a radius of 2 pc, and have velocities in a similar range with a median velocity dispersion of ~1 km s-1. We use NH3, N2H+, and CS velocities to calculate near and far kinematic distances to those groups. Results: We obtain 296 groups of ATLASGAL sources in the first quadrant and 393 groups in the fourth quadrant, which are coherent in space and velocity. We analyse HI self-absorption and HI absorption to resolve the kinematic distance ambiguity to 689 complexes of submm clumps. They are associated with 12CO emission probing large-scale structure and 13CO (1-0) line as well as the 870 μm dust continuum on a smaller scale. We obtain a scale height of ~28 ± 2 pc and displacement below the Galactic midplane of ~-7 ± 1 pc. Within distances from 2 to 18 kpc ATLASGAL clumps have a broad range of <span class="hlt">gas</span> masses with a median of 1050 M⊙ as well as a wide <span class="hlt">distribution</span> of radii with a median of 0.4 pc. Their <span class="hlt">distribution</span> in galactocentric radii is correlated with spiral arms. Conclusions: Using a statistically significant</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.453..721V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.453..721V"><span>The alignment and shape of dark matter, stellar, and hot <span class="hlt">gas</span> <span class="hlt">distributions</span> in the EAGLE and cosmo-OWLS simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Velliscig, Marco; Cacciato, Marcello; Schaye, Joop; Crain, Robert A.; Bower, Richard G.; van Daalen, Marcel P.; Dalla Vecchia, Claudio; Frenk, Carlos S.; Furlong, Michelle; McCarthy, I. G.; Schaller, Matthieu; Theuns, Tom</p> <p>2015-10-01</p> <p>We report the alignment and shape of dark matter, stellar, and hot <span class="hlt">gas</span> <span class="hlt">distributions</span> in the EAGLE (Evolution and Assembly of GaLaxies and their Environments) and cosmo-OWLS (OverWhelmingly Large Simulations) simulations. The combination of these state-of-the-art hydrodynamical cosmological simulations enables us to span four orders of magnitude in halo mass (11 ≤ log10(M200/[ h-1 M⊙]) ≤ 15), a wide radial range (-2.3 ≤ log10(r/[ h-1 Mpc]) ≤ 1.3) and redshifts 0 ≤ z ≤ 1. The shape parameters of the dark matter, stellar and hot <span class="hlt">gas</span> <span class="hlt">distributions</span> follow qualitatively similar trends: they become more aspherical (and triaxial) with increasing halo mass, radius, and redshift. We measure the misalignment of the baryonic components (hot <span class="hlt">gas</span> and stars) of galaxies with their host halo as a function of halo mass, radius, redshift, and galaxy type (centrals versus satellites and early- versus late-type). Overall, galaxies align well with the local <span class="hlt">distribution</span> of the total (mostly dark) matter. However, the stellar <span class="hlt">distributions</span> on galactic scales exhibit a median misalignment of about 45-50 deg with respect to their host haloes. This misalignment is reduced to 25-30 deg in the most massive haloes (13 ≤ log10(M200/[ h-1 M⊙]) ≤ 15). Half of the disc galaxies in the EAGLE simulations have a misalignment angle with respect to their host haloes larger than 40 deg. We present fitting functions and tabulated values for the probability <span class="hlt">distribution</span> of galaxy-halo misalignment to enable a straightforward inclusion of our results into models of galaxy formations based on purely collisionless N-body simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6104609','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6104609"><span>South American oil and <span class="hlt">gas</span> fields: Reasons for their presence and <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pratsch, J.C. )</p> <p>1993-02-01</p> <p>South American oil and <span class="hlt">gas</span> fields occur in geographic clusters. Their concentration in relatively small producing areas depends on the present location of the hydrocarbon generating depocenter and results from the basinal oil and <span class="hlt">gas</span> migration history. By defining both, existing field locations can be explained and new field occurrences can be predicted, including those in overthrust plays. One-and two-stage hydrocarbon migration processes exist: In one-stage migration oil and <span class="hlt">gas</span> migrate directly from the generating source beds into reservoirs, like in Maturin Basin or Maranon Basin fields. In two-stage migration oil and <span class="hlt">gas</span> first migrate into a primary reservoir level, from there during a second migration phase into a (commonly younger) secondary reservoir level. Here, the original source beds may be over-mature or even metamorphosed today; examples here are the Maturin, Llanos and Oriente Basins, possibly offshore Trinidad. Definition of generating depocenters is the task of regional exploration. Oil and <span class="hlt">gas</span> migration analysis is one result of semi-detailed structural mapping using gravity, magnetic, seismic reflection and geochemical data. Oil and <span class="hlt">gas</span> exploration in two-stage migration basins are especially challenging, like in the Austral Basin of southern Argentina and Chile or possibly in the Parana Basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22270929','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22270929"><span>TOWARD A DETERMINISTIC MODEL OF PLANETARY FORMATION. VII. ECCENTRICITY <span class="hlt">DISTRIBUTION</span> OF <span class="hlt">GAS</span> GIANTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ida, S.; Lin, D. N. C.</p> <p>2013-09-20</p> <p>The ubiquity of planets and diversity of planetary systems reveal that planet formation encompasses many complex and competing processes. In this series of papers, we develop and upgrade a population synthesis model as a tool to identify the dominant physical effects and to calibrate the range of physical conditions. Recent planet searches have led to the discovery of many multiple-planet systems. Any theoretical models of their origins must take into account dynamical interactions between emerging protoplanets. Here, we introduce a prescription to approximate the close encounters between multiple planets. We apply this method to simulate the growth, migration, and dynamical interaction of planetary systems. Our models show that in relatively massive disks, several <span class="hlt">gas</span> giants and rocky/icy planets emerge, migrate, and undergo dynamical instability. Secular perturbation between planets leads to orbital crossings, eccentricity excitation, and planetary ejection. In disks with modest masses, two or less <span class="hlt">gas</span> giants form with multiple super-Earths. Orbital stability in these systems is generally maintained and they retain the kinematic structure after <span class="hlt">gas</span> in their natal disks is depleted. These results reproduce the observed planetary mass-eccentricity and semimajor axis-eccentricity correlations. They also suggest that emerging <span class="hlt">gas</span> giants can scatter residual cores to the outer disk regions. Subsequent in situ <span class="hlt">gas</span> accretion onto these cores can lead to the formation of distant (∼> 30 AU) <span class="hlt">gas</span> giants with nearly circular orbits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Nanos...7.7734S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Nanos...7.7734S"><span><span class="hlt">Gas</span> phase condensation of superparamagnetic iron oxide-silica nanoparticles - control of the intraparticle phase <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stötzel, C.; Kurland, H.-D.; Grabow, J.; Müller, F. A.</p> <p>2015-04-01</p> <p> consisting of a γ-Fe2O3 and a SiO2 hemisphere to γ-Fe2O3 NPs each carrying one small SiO2 lens on its surface, (ii) the multiple γ-Fe2O3 inclusions accumulate at the NPs' inner surfaces, and (iii) all composite NPs are covered by a thin layer of amorphous SiO2. These morphological characteristics are attributed to (i) the phase segregation of iron oxide and silica within the condensed Fe2O3-SiO2 droplets, (ii) the temperature gradient within these droplets which arises during rapid cooling in the CoLAVA process, and (iii) the significantly lower surface energy of silica when compared to iron oxide. The proposed growth mechanism of these Fe2O3-SiO2 composite NPs during <span class="hlt">gas</span> phase condensation can be transferred to other systems comprising a glass-network former and another component that is insoluble in the regarding glass. Thus, our model will facilitate the development of novel functional composite NPs for applications in biomedicine, optics, electronics, or catalysis. Electronic supplementary information (ESI) available: Infrared absorption of the raw powders hematite and quartz (section S1), TEM investigation of the spatial <span class="hlt">distribution</span> of the γ-Fe2O3 inclusions (section S2), particle size <span class="hlt">distributions</span> of the Fe2O3@SiO2 nanopowder samples (section S3), ζ-potentials of aqueous dispersions of all γ-Fe2O3@SiO2 nanopowder samples (section S4), silanization of Fe2O3@SiO2 composite nanopowders with [3-(2,3-epoxypropoxy)-propyl]trimethoxysilane (section S5), and animation composed of TEM micrographs of Fe2O3@SiO2 NPs recorded at incrementally altered tilt angles (``Rotating Fe2O3@SiO2 NP.avi''). See DOI: 10.1039/c5nr00845j</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995JGR...10023027K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995JGR...10023027K"><span>Aerosol size <span class="hlt">distribution</span> and aerosol water content measurements during Atlantic Stratocumulus Transition Experiment/Marine Aerosol and <span class="hlt">Gas</span> Exchange</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Y.; Sievering, H.; Boatman, J.; Wellman, D.; Pszenny, A.</p> <p>1995-11-01</p> <p>Aerosol size <span class="hlt">distribution</span> data measured during the June 1992 Marine Aerosol and <span class="hlt">Gas</span> Exchange experiment are analyzed to investigate the characteristics of fine marine aerosol particles measured over the North Atlantic near the Azores Islands. Measured aerosol size <span class="hlt">distribution</span> data were corrected using the corrected size calibration data based on the optical properties of particles being measured. The corrected size <span class="hlt">distribution</span> data were then approximated with either one or two lognormal size <span class="hlt">distributions</span>, depending on air mass conditions. Under clean air mass conditions <3 μm diameter aerosol size <span class="hlt">distributions</span> typically exhibited two modes, consisting of an accumulation mode and the small end of the sea-salt particle mode. However, under the influence of continental polluted air masses, the aerosol size <span class="hlt">distribution</span> was dominated by <1 μm diameter particles in a single mode with an increased aerosol concentration. Aerosol water content of accumulation mode marine aerosols was estimated from differences between several series of ambient and dried aerosol size <span class="hlt">distributions</span>. The average aerosol water fraction was 0.31, which is in good agreement with an empirical aerosol growth model estimate. The average rate of SO4= production in the accumulation mode aerosol water by H2O2 oxidation was estimated to be <7×10-10 mol L-1 s-1, which is an insignificant contributor to the observed non-sea-salt SO4= in the accumulation mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2010-06-28/pdf/2010-15633.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2010-06-28/pdf/2010-15633.pdf"><span>75 FR 36615 - Pipeline Safety: Information Collection <span class="hlt">Gas</span> <span class="hlt">Distribution</span> Annual Report Form</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2010-06-28</p> <p>... number of EFVs in the system at the end of the year on single- family residential services. The purpose... above or below ground, inside or outside, and if it connects a <span class="hlt">main</span>-to- <span class="hlt">main</span>, a <span class="hlt">main</span>-to-service, or a... material to which the leaking/pulled-out compression fitting was connected.'' and ``Enter the...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=Thermodynamics&pg=3&id=EJ1079262','ERIC'); return false;" href="http://eric.ed.gov/?q=Thermodynamics&pg=3&id=EJ1079262"><span>Investigating Friction as a <span class="hlt">Main</span> Source of Entropy Generation in the Expansion of Confined <span class="hlt">Gas</span> in a Piston-and-Cylinder Device</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Kang, Dun-Yen; Liou, Kai-Hsin; Chang, Wei-Lun</p> <p>2015-01-01</p> <p>The expansion or compression of <span class="hlt">gas</span> confined in a piston-and-cylinder device is a classic working example used for illustrating the First and Second Laws of Thermodynamics. The balance of energy and entropy enables the estimation of a number of thermodynamic properties. The entropy generation (also called entropy production) resulting from this…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25018592','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25018592"><span>Alexandrium fundyense cysts in the Gulf of <span class="hlt">Maine</span>: long-term time series of abundance and <span class="hlt">distribution</span>, and linkages to past and future blooms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Donald M; Keafer, Bruce A; Kleindinst, Judith L; McGillicuddy, Dennis J; Martin, Jennifer L; Norton, Kerry; Pilskaln, Cynthia H; Smith, Juliette L; Sherwood, Christopher R; Butman, Bradford</p> <p>2014-05-01</p> <p>Here we document Alexandrium fundyense cyst abundance and <span class="hlt">distribution</span> patterns over nine years (1997 and 2004-2011) in the coastal waters of the Gulf of <span class="hlt">Maine</span> (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with > 300 cysts cm(-3)) are evident, one in the Bay of Fundy (BOF) and one in mid-coast <span class="hlt">Maine</span>. Overall, seedbed locations remained relatively constant through time, but their area varied 3-4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast <span class="hlt">Maine</span> seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0-1 and the 0-3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts → blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms → cysts). There are, however, significant positive correlations between 0-3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DSRII.103....6A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DSRII.103....6A"><span>Alexandrium fundyense cysts in the Gulf of <span class="hlt">Maine</span>: Long-term time series of abundance and <span class="hlt">distribution</span>, and linkages to past and future blooms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, Donald M.; Keafer, Bruce A.; Kleindinst, Judith L.; McGillicuddy, Dennis J.; Martin, Jennifer L.; Norton, Kerry; Pilskaln, Cynthia H.; Smith, Juliette L.; Sherwood, Christopher R.; Butman, Bradford</p> <p>2014-05-01</p> <p>Here we document Alexandrium fundyense cyst abundance and <span class="hlt">distribution</span> patterns over nine years (1997 and 2004-2011) in the coastal waters of the Gulf of <span class="hlt">Maine</span> (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with>300 cysts cm-3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast <span class="hlt">Maine</span>. Overall, seedbed locations remained relatively constant through time, but their area varied 3-4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast <span class="hlt">Maine</span> seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0-1 and the 0-3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts→blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms→cysts). There are, however, significant positive correlations between 0-3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell abundance (e</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70111431','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70111431"><span>Alexandrium fundyense cysts in the Gulf of <span class="hlt">Maine</span>: long-term time series of abundance and <span class="hlt">distribution</span>, and linkages to past and future blooms</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Anderson, Donald M.; Keafer, Bruce A.; Kleindinst, Judith L.; McGillicuddy, Dennis J.; Martin, Jennifer L.; Norton, Kerry; Pilskaln, Cynthia H.; Smith, Juliette L.; Sherwood, Christopher R.; Butman, Bradford</p> <p>2014-01-01</p> <p>Here we document Alexandrium fundyense cyst abundance and <span class="hlt">distribution</span> patterns over nine years (1997 and 2004–2011) in the coastal waters of the Gulf of <span class="hlt">Maine</span> (GOM) and identify linkages between those patterns and several metrics of the severity or magnitude of blooms occurring before and after each autumn cyst survey. We also explore the relative utility of two measures of cyst abundance and demonstrate that GOM cyst counts can be normalized to sediment volume, revealing meaningful patterns equivalent to those determined with dry weight normalization. Cyst concentrations were highly variable spatially. Two distinct seedbeds (defined here as accumulation zones with>300 cysts cm−3) are evident, one in the Bay of Fundy (BOF) and one in mid-coast <span class="hlt">Maine</span>. Overall, seedbed locations remained relatively constant through time, but their area varied 3–4 fold, and total cyst abundance more than 10 fold among years. A major expansion of the mid-coast <span class="hlt">Maine</span> seedbed occurred in 2009 following an unusually intense A. fundyense bloom with visible red-water conditions, but that feature disappeared by late 2010. The regional system thus has only two seedbeds with the bathymetry, sediment characteristics, currents, biology, and environmental conditions necessary to persist for decades or longer. Strong positive correlations were confirmed between the abundance of cysts in both the 0–1 and the 0–3 cm layers of sediments in autumn and geographic measures of the extent of the bloom that occurred the next year (i.e., cysts→blooms), such as the length of coastline closed due to shellfish toxicity or the southernmost latitude of shellfish closures. In general, these metrics of bloom geographic extent did not correlate with the number of cysts in sediments following the blooms (blooms→cysts). There are, however, significant positive correlations between 0–3 cm cyst abundances and metrics of the preceding bloom that are indicative of bloom intensity or vegetative cell</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AtmEn.133...60J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AtmEn.133...60J"><span>Size <span class="hlt">distribution</span> and concentration of soot generated in oil and <span class="hlt">gas</span>-fired residential boilers under different combustion conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiménez, Santiago; Barroso, Jorge; Pina, Antonio; Ballester, Javier</p> <p>2016-05-01</p> <p>In spite of the relevance of residential heating burners in the global emission of soot particles to the atmosphere, relatively little information on their properties (concentration, size <span class="hlt">distribution</span>) is available in the literature, and even less regarding the dependence of those properties on the operating conditions. Instead, the usual procedure to characterize those emissions is to measure the smoke opacity by several methods, among which the blackening of a paper after filtering a fixed amount of <span class="hlt">gas</span> (Bacharach test) is predominant. In this work, the size <span class="hlt">distributions</span> of the particles generated in the combustion of a variety of gaseous and liquid fuels in a laboratory facility equipped with commercial burners have been measured with a size classifier coupled to a particle counter in a broad range of operating conditions (air excesses), with simultaneous determination of the Bacharach index. The shape and evolution of the <span class="hlt">distribution</span> with progressively smaller oxygen concentrations depends essentially on the state of the fuel: whereas the combustion of the gases results in monomodal <span class="hlt">distributions</span> that 'shift' towards larger diameters, in the case of the <span class="hlt">gas</span>-oils an ultrafine mode is always observed, and a secondary mode of coarse particle grows in relevance. In both cases, there is a strong, exponential correlation between the total mass concentration and the Bacharach opacity index, quite similar for both groups of fuels. The empirical expressions proposed may allow other researchers to at least estimate the emissions of numerous combustion facilities routinely characterized by their smoke opacities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9298E..0NL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9298E..0NL"><span>A measurement plan of <span class="hlt">gas</span> concentration and temperature <span class="hlt">distribution</span> reconstruction based on the tunable diode laser absorption tomography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Zhao-ran; Jin, Xing; Wang, Guang-yu; Song, Jun-ling</p> <p>2014-11-01</p> <p>Based on the tunable diode laser absorption tomography, <span class="hlt">gas</span> concentration and temperature two-dimensional <span class="hlt">distribution</span> reconstruction is realized using algebraic iterative reconstruction technique (ART). A measurement plan is proposed based on the beam splitting lens, and the corresponding beam arrangement is put forward. The beam splitting lenses are used in the plan to making one laser beam cross the measurement area repeatedly. Thus can raise the utilization ratio of laser beam and simplify the structure of measurement platform. A model for H2O vapor concentration and temperature <span class="hlt">distribution</span> is assumed, and numerical simulation is utilized using two absorption transitions. The feasibility of the measurement plan is proved by the simulation experiment. The influences of initial beam angle, the number of beams and grids on the reconstructed results are analyzed numerically. A concept of phantom description method using in simulation experiments is proposed in order to getting closer to the real experiments. The phantom description method is used in the numerical simulation to evaluating concentration and temperature field reconstruction. Through this method, expected data is sampled from initial data, and reconstructed result is obtained by interpolation. The influence of random errors in projections on <span class="hlt">distribution</span> reconstruction is also analyzed. The measurement plan can reconstruct the <span class="hlt">gas</span> concentration and temperature <span class="hlt">distribution</span> with a simplified measurement platform using beam splitting lenses. The feasibility of the phantom description method is also proved by the simulation experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006TellB..58..390K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006TellB..58..390K"><span>Carbon isotope evidence for the latitudinal <span class="hlt">distribution</span> and wind speed dependence of the air-sea <span class="hlt">gas</span> transfer velocity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krakauer, Nir Y.; Randerson, James T.; Primeau, François W.; Gruber, Nicolas; Menemenlis, Dimitris</p> <p>2006-11-01</p> <p>The air-sea <span class="hlt">gas</span> transfer velocity is an important determinant of the exchange of gases, including CO2, between the atmosphere and ocean, but the magnitude of the transfer velocity and what factors control it remains poorly known. Here, we use oceanic and atmospheric observations of 14C and 13C to constrain the global mean <span class="hlt">gas</span> transfer velocity as well as the exponent of its wind speed dependence, utilizing the distinct signatures left by the air-sea exchange of 14CO2 and 13CO2. While the atmosphere and ocean inventories of 14CO2 and 13CO2 constrain the mean <span class="hlt">gas</span> transfer velocity, the latitudinal pattern in the atmospheric and oceanic 14C and 13C <span class="hlt">distributions</span> contain information about the wind speed dependence. We computed the uptake of bomb 14C by the ocean for different transfer velocity patterns using pulse response functions from an ocean general circulation model, and evaluated the match between the predicted bomb 14C concentrations and observationally based estimates for the 1970s-1990s. Using a wind speed climatology based on satellite measurements, we solved either for the best-fit global relationship between <span class="hlt">gas</span> exchange and mean wind speed or for the mean <span class="hlt">gas</span> transfer velocity over each of 11 ocean regions. We also compared the predicted consequences of different <span class="hlt">gas</span> exchange relationships on the rate of change and interhemisphere gradient of 14C in atmospheric CO2 with tree-ring and atmospheric measurements. Our results suggest that globally, the dependence of the air-sea <span class="hlt">gas</span> transfer velocity on wind speed is close to linear, with an exponent of 0.5 +/- 0.4, and that the global mean <span class="hlt">gas</span> transfer velocity at a Schmidt number of 660 is 20 +/- 3 cm/hr, similar to the results of previous analyses. We find that the air-sea flux of 13C estimated from atmosphere and ocean observations also suggests a lower than quadratic dependence of <span class="hlt">gas</span> exchange on wind speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3109899','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3109899"><span><span class="hlt">Main</span> Report</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2006-01-01</p> <p> scientific literature. The criteria were <span class="hlt">distributed</span> among three <span class="hlt">main</span> categories for each condition: The availability and characteristics of the screening test;The availability and complexity of diagnostic services; andThe availability and efficacy of treatments related to the conditions. A survey process utilizing a data collection instrument was used to gather expert opinion on the conditions in the first tier of the assessment. The data collection format and survey provided the opportunity to quantify expert opinion and to obtain the views of a diverse set of interest groups (necessary due to the subjective nature of some of the criteria). Statistical analysis of data produced a score for each condition, which determined its ranking and initial placement in one of three categories (high scoring, moderately scoring, or low scoring/absence of a newborn screening test). In the second tier of these analyses, the evidence base related to each condition was assessed in depth (e.g., via systematic reviews of reference lists including MedLine, PubMed and others; books; Internet searches; professional guidelines; clinical evidence; and cost/economic evidence and modeling). The fact sheets reflecting these analyses were evaluated by at least two acknowledged experts for each condition. These experts assessed the data and the associated references related to each criterion and provided corrections where appropriate, assigned a value to the level of evidence and the quality of the studies that established the evidence base, and determined whether there were significant variances from the survey data. Survey results were subsequently realigned with the evidence obtained from the scientific literature during the second-tier analysis for all objective criteria, based on input from at least three acknowledged experts in each condition. The information from these two tiers of assessment was then considered with regard to the overriding principles and other technology or condition</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1343742-linking-basin-scale-pore-scale-gas-hydrate-distribution-patterns-diffusion-dominated-marine-hydrate-systems"><span>Linking basin-scale and pore-scale <span class="hlt">gas</span> hydrate <span class="hlt">distribution</span> patterns in diffusion-dominated marine hydrate systems</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Nole, Michael; Daigle, Hugh; Cook, Ann E.; ...</p> <p>2017-02-07</p> <p>The goal of this study is to computationally determine the potential <span class="hlt">distribution</span> patterns of diffusion-driven methane hydrate accumulations in coarse-grained marine sediments. Diffusion of dissolved methane in marine <span class="hlt">gas</span> hydrate systems has been proposed as a potential transport mechanism through which large concentrations of hydrate can preferentially accumulate in coarse-grained sediments over geologic time. Using one-dimensional compositional reservoir simulations, we examine hydrate <span class="hlt">distribution</span> patterns at the scale of individual sand layers (1 to 20 m thick) that are deposited between microbially active fine-grained material buried through the <span class="hlt">gas</span> hydrate stability zone (GHSZ). We then extrapolate to two- dimensional and basin-scalemore » three-dimensional simulations, where we model dipping sands and multilayered systems. We find that properties of a sand layer including pore size <span class="hlt">distribution</span>, layer thickness, dip, and proximity to other layers in multilayered systems all exert control on diffusive methane fluxes toward and within a sand, which in turn impact the <span class="hlt">distribution</span> of hydrate throughout a sand unit. In all of these simulations, we incorporate data on physical properties and sand layer geometries from the Terrebonne Basin <span class="hlt">gas</span> hydrate system in the Gulf of Mexico. We demonstrate that diffusion can generate high hydrate saturations (upward of 90%) at the edges of thin sands at shallow depths within the GHSZ, but that it is ineffective at producing high hydrate saturations throughout thick (greater than 10 m) sands buried deep within the GHSZ. As a result, we find that hydrate in fine-grained material can preserve high hydrate saturations in nearby thin sands with burial.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/74047','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/74047"><span>Atlas of Northern Gulf of Mexico <span class="hlt">Gas</span> and Oil Reservoirs: Procedures and examples of resource <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Seni, S.J.; Finley, R.J.</p> <p>1995-06-01</p> <p>The objective of the program is to produce a reservoir atlas series of the Gulf of Mexico that (1) classifies and groups offshore oil and <span class="hlt">gas</span> reservoirs into a series of geologically defined reservoir plays, (2) compiles comprehensive reservoir play information that includes descriptive and quantitative summaries of play characteristics, cumulative production, reserves, original oil and <span class="hlt">gas</span> in place, and various other engineering and geologic data, (3) provides detailed summaries of representative type reservoirs for each play, and (4) organizes computerized tables of reservoir engineering data into a geographic information system (GIS). The primary product of the program will be an oil and <span class="hlt">gas</span> atlas series of the offshore Northern Gulf of Mexico and a computerized geographical information system of geologic and engineering data linked to reservoir location.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1326467','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1326467"><span>Fast Spatially Resolved Exhaust <span class="hlt">Gas</span> Recirculation (EGR) <span class="hlt">Distribution</span> Measurements in an Internal Combustion Engine Using Absorption Spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E.; Perfetto, Anthony; Geckler, Sam; Partridge, William P.</p> <p>2015-09-01</p> <p>One effective method of reducing NO<sub>x </sub>emissions while improving efficiency is exhaust <span class="hlt">gas</span> recirculation (EGR) in internal combustion engines. But, insufficient mixing between fresh air and exhaust <span class="hlt">gas</span> can lead to cycle-to-cycle and cylinder-to-cylinder nonuniform charge <span class="hlt">gas</span> mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. Furthermore, a sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR <span class="hlt">distributions</span> in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO<sub>2</sub> concentration at various locations in the intake manifold. Our study employed mid-infrared light sources tuned to an absorption band of CO<sub>2</sub> near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR <span class="hlt">distributions</span> in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26253286','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26253286"><span>Fast spatially resolved exhaust <span class="hlt">gas</span> recirculation (EGR) <span class="hlt">distribution</span> measurements in an internal combustion engine using absorption spectroscopy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E; Perfetto, Anthony; Geckler, Sam; Partridge, William P</p> <p>2015-09-01</p> <p>Exhaust <span class="hlt">gas</span> recirculation (EGR) in internal combustion engines is an effective method of reducing NOx emissions while improving efficiency. However, insufficient mixing between fresh air and exhaust <span class="hlt">gas</span> can lead to cycle-to-cycle and cylinder-to-cylinder non-uniform charge <span class="hlt">gas</span> mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. A sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR <span class="hlt">distributions</span> in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO2 concentration at various locations in the intake manifold. The study employed mid-infrared light sources tuned to an absorption band of CO2 near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR <span class="hlt">distributions</span> in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/pages/biblio/1326467-fast-spatially-resolved-exhaust-gas-recirculation-egr-distribution-measurements-internal-combustion-engine-using-absorption-spectroscopy','SCIGOV-DOEP'); return false;" href="https://www.osti.gov/pages/biblio/1326467-fast-spatially-resolved-exhaust-gas-recirculation-egr-distribution-measurements-internal-combustion-engine-using-absorption-spectroscopy"><span>Fast Spatially Resolved Exhaust <span class="hlt">Gas</span> Recirculation (EGR) <span class="hlt">Distribution</span> Measurements in an Internal Combustion Engine Using Absorption Spectroscopy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGES</a></p> <p>Yoo, Jihyung; Prikhodko, Vitaly; Parks, James E.; ...</p> <p>2015-09-01</p> <p>One effective method of reducing NOx emissions while improving efficiency is exhaust <span class="hlt">gas</span> recirculation (EGR) in internal combustion engines. But, insufficient mixing between fresh air and exhaust <span class="hlt">gas</span> can lead to cycle-to-cycle and cylinder-to-cylinder nonuniform charge <span class="hlt">gas</span> mixtures of a multi-cylinder engine, which can in turn reduce engine performance and efficiency. Furthermore, a sensor packaged into a compact probe was designed, built and applied to measure spatiotemporal EGR <span class="hlt">distributions</span> in the intake manifold of an operating engine. The probe promotes the development of more efficient and higher-performance engines by resolving high-speed in situ CO2 concentration at various locations in themore » intake manifold. Our study employed mid-infrared light sources tuned to an absorption band of CO2 near 4.3 μm, an industry standard species for determining EGR fraction. The calibrated probe was used to map spatial EGR <span class="hlt">distributions</span> in an intake manifold with high accuracy and monitor cycle-resolved cylinder-specific EGR fluctuations at a rate of up to 1 kHz.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/203612','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/203612"><span>Application of the octanol-air partition coefficient for describing particle/<span class="hlt">gas</span> <span class="hlt">distribution</span> of chlorinated aromatics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Harner, T.; Bidleman, T.; Falconer, R.; Mackay, D.</p> <p>1995-12-31</p> <p>Partitioning of chlorinated aromatics between the <span class="hlt">gas</span> and aerosol particulate phases can be explained by adsorption onto active sites on the surface of the aerosol and/or by absorption into a liquid film. In both cases the particle/<span class="hlt">gas</span> <span class="hlt">distribution</span> coefficient, K{sub P}, is well correlated with the vapor pressure of the compound. The correlation improves for the adsorption model by including a shape parameter which takes into account the planarity of the molecule. This investigation will consider using the octanol-air partition coefficient, K{sub OA}, as a surrogate for K{sub p}. A method for measuring K{sub OA} is described and results are presented for several PCBs over the temperature range {minus}10 C to + 30 C. The temperature dependence of K{sub P} for PCBs, measured in controlled laboratory experiments, is more closely described by the temperature slope of K{sub OA} than vapor pressure. This supports the hypothesis that absorption into an organic, liquid film is a plausible mechanism for sorption of chlorinated aromatics to urban aerosols. K{sub OA} is also believed to be a valuable descriptor of partitioning of persistent organochlorine chemicals between the atmosphere and lipid-containing phases such as soil and vegetation. Results of particle/<span class="hlt">gas</span> <span class="hlt">distributions</span> for PCBs and PCNs (polychlorinated naphthalenes) from field samples collected in Toronto and Chicago are presented and discussed with relation to OA, vapor pressure and planarity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/462535','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/462535"><span>Application of the octanol-air partition coefficient for describing particle/<span class="hlt">gas</span> <span class="hlt">distribution</span> of persistent aromatics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Harner, T.; Bidleman, T.; Falconer, R.; Mackay, D.</p> <p>1995-12-31</p> <p>Partitioning of chemicals between the <span class="hlt">gas</span> and aerosol particulate phases can be explained by adsorption onto active sites on the surface of the aerosol, and/or by absorption into a liquid film. In both cases the particle/<span class="hlt">gas</span> <span class="hlt">distribution</span> coefficient, K{sub P}, is well correlated with vapor pressure for compounds in the same class. This investigation will consider using the octanol-air partition coefficient, K{sub OA}, as an alternate fitting parameter for K{sub P}. A method for measuring K{sub OA} is described and results are presented for several polychlorinated biphenyls (PCBs), polynuclear aromatic hydrocarbons (PAHs), and polychlorinated naphthalenes (PCNs) over the temperature range {minus}10 C to + 40 C. Results of particle/<span class="hlt">gas</span> <span class="hlt">distributions</span> for PCBs, PAHs, and PCN, from field samples collected in Chicago are presented and discussed with relation to K{sub OA}, vapor pressure and the planarity of the compound. Correlation of K{sub P} with K{sub OA} reduces differences between compound classes and is able to explain the enhanced partitioning onto particles for coplanar PCBs which vapor pressure alone is unable to resolve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LaPhL..13g5703P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LaPhL..13g5703P"><span>Spatial <span class="hlt">distribution</span> of the optogalvanic signal in a microplasma detector for lab-on-a-chip <span class="hlt">gas</span> analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Persson, A.; Berglund, M.</p> <p>2016-07-01</p> <p><span class="hlt">Gas</span> sensors are characterized by their sensitivity and selectivity. This is preferably combined with versatility, where the selectivity can be altered, without complex modifications and whiteout losing sensitivity. If aimed at lab-on-a-chip applications, the sensor also must be able to analyze small samples. Today, sensors combining selectivity and versatility for chip-level <span class="hlt">gas</span> analysis are scarce; however, this paper investigates how miniaturized optogalvanic spectroscopy can fill this gap. By studying the spatial <span class="hlt">distribution</span> of the optogalvanic signal inside a microplasma, it is shown that the signal is generated in the minuscule <span class="hlt">gas</span> volume of the sheath surrounding the plasma probe that collects it. Nevertheless, a strong and stable spectroscopic signal can be extracted from the sheath, and the sample concentrations can be calculated using straightforward plasma theory. The minimum detectable absorption and the noise equivalent absorption sensitivity of the system are estimated to be less than 1.4  ×  10-9 Hz-0.5 and 2.8  ×  10-9 cm-1 Hz-0.5, respectively, without cavity enhancement. Combined with inherited versatility from absorption spectroscopy and the capability of handling sub-nanogram samples, this makes optogalvanic spectrometry an excellent candidate for future lab-on-a-chip <span class="hlt">gas</span> analyzers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011IJTFM.131..205T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011IJTFM.131..205T"><span>Dependence of Ozone Generation on <span class="hlt">Gas</span> Temperature <span class="hlt">Distribution</span> in AC Atmospheric Pressure Dielectric Barrier Discharge in Oxygen</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takahashi, Go; Akashi, Haruaki</p> <p></p> <p>AC atmospheric pressure multi-filament dielectric barrier discharge in oxygen has been simulated using two dimensional fluid model. In the discharge, three kinds of streamers have been obtained. They are primary streamers, small scale streamers and secondary streamers. The primary streamers are <span class="hlt">main</span> streamers in the discharge and the small scale streamers are formed after the ceasing of the primary streamers. And the secondary streamers are formed on the trace of the primary streamers. In these streamers, the primary and the small scale streamers are very effective to generate O(3P) oxygen atoms which are precursor of ozone. And the ozone is generated <span class="hlt">mainly</span> in the vicinity of the dielectrics. In high <span class="hlt">gas</span> temperature region, ozone generation decreases in general. However, increase of the O(3P) oxygen atom density in high <span class="hlt">gas</span> temperature region compensates decrease of ozone generation rate coefficient. As a result, amount of ozone generation has not changed. But if the effect of <span class="hlt">gas</span> temperature was neglected, amount of ozone generation increases 10%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GML....34...89M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GML....34...89M"><span><span class="hlt">Distribution</span> and geological control of mud volcanoes and other fluid/free <span class="hlt">gas</span> seepage features in the Mediterranean Sea and nearby Gulf of Cadiz</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mascle, Jean; Mary, Flore; Praeg, Daniel; Brosolo, Laetitia; Camera, Laurent; Ceramicola, Silvia; Dupré, Stéphanie</p> <p>2014-06-01</p> <p>Existing knowledge on the <span class="hlt">distribution</span> of mud volcanoes (MVs) and other significant fluid/free <span class="hlt">gas</span>-venting features (mud cones, mud pies, mud-brine pools, mud carbonate cones, <span class="hlt">gas</span> chimneys and, in some cases, pockmark fields) discovered on the seafloor of the Mediterranean Sea and in the nearby Gulf of Cadiz has been compiled using regional geophysical information (including multibeam coverage of most deepwater areas). The resulting dataset comprises both features proven from geological sampling, or in situ observations, and many previously unrecognized MVs inferred from geophysical evidence. The synthesis reveals that MVs clearly have non-random <span class="hlt">distributions</span> that correspond to two <span class="hlt">main</span> geodynamic settings: (1) the vast majority occur along the various tectono-sedimentary accretionary wedges of the Africa-Eurasia subduction zone, particularly in the central and eastern Mediterranean basins (external Calabrian Arc, Mediterranean Ridge, Florence Rise) but also along its westernmost boundary in the Gulf of Cadiz; (2) other MVs characterize thick depocentres along parts of the Mesozoic passive continental margins that border Africa from eastern Tunisia to the Levantine coasts, particularly off Egypt and, locally, within some areas of the western Mediterranean back-arc basins. Meaningfully accounting for MV <span class="hlt">distribution</span> necessitates evidence of overpressured fluids and mud-rich layers. In addition, cross-correlations between MVs and other GIS-based data, such as maps of the Messinian evaporite basins and/or active (or recently active) tectonic trends, stress the importance of assessing geological control in terms of the presence, or not, of thick seals and potential conduits. It is contended that new MV discoveries may be expected in the study region, particularly along the southern Ionian Sea continental margins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24678140','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24678140"><span>Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: <span class="hlt">Main</span> Ash-Forming Elements and Ash <span class="hlt">Distribution</span> with a Focus on Phosphorus.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Skoglund, Nils; Grimm, Alejandro; Ohman, Marcus; Boström, Dan</p> <p>2014-02-20</p> <p>This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the <span class="hlt">distribution</span> of <span class="hlt">main</span> ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash <span class="hlt">distribution</span> was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%-95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and magnesium</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3964734','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3964734"><span>Combustion of Biosolids in a Bubbling Fluidized Bed, Part 1: <span class="hlt">Main</span> Ash-Forming Elements and Ash <span class="hlt">Distribution</span> with a Focus on Phosphorus</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>This is the first in a series of three papers describing combustion of biosolids in a 5-kW bubbling fluidized bed, the ash chemistry, and possible application of the ash produced as a fertilizing agent. This part of the study aims to clarify whether the <span class="hlt">distribution</span> of <span class="hlt">main</span> ash forming elements from biosolids can be changed by modifying the fuel matrix, the crystalline compounds of which can be identified in the raw materials and what role the total composition may play for which compounds are formed during combustion. The biosolids were subjected to low-temperature ashing to investigate which crystalline compounds that were present in the raw materials. Combustion experiments of two different types of biosolids were conducted in a 5-kW benchscale bubbling fluidized bed at two different bed temperatures and with two different additives. The additives were chosen to investigate whether the addition of alkali (K2CO3) and alkaline-earth metal (CaCO3) would affect the speciation of phosphorus, so the molar ratios targeted in modified fuels were P:K = 1:1 and P:K:Ca = 1:1:1, respectively. After combustion the ash fractions were collected, the ash <span class="hlt">distribution</span> was determined and the ash fractions were analyzed with regards to elemental composition (ICP-AES and SEM-EDS) and part of the bed ash was also analyzed qualitatively using XRD. There was no evidence of zeolites in the unmodified fuels, based on low-temperature ashing. During combustion, the biosolid pellets formed large bed ash particles, ash pellets, which contained most of the total ash content (54%–95% (w/w)). This ash fraction contained most of the phosphorus found in the ash and the only phosphate that was identified was a whitlockite, Ca9(K,Mg,Fe)(PO4)7, for all fuels and fuel mixtures. With the addition of potassium, cristobalite (SiO2) could no longer be identified via X-ray diffraction (XRD) in the bed ash particles and leucite (KAlSi2O6) was formed. Most of the alkaline-earth metals calcium and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120008621','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120008621"><span>Variability of Disk Emission in Pre-<span class="hlt">Main</span> Sequence and Related Stars. II. Variability in the <span class="hlt">Gas</span> and Dust Emission of the Herbig Fe Star SAO 206462</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sitko, Michael L.; Day, Amanda N.; Kimes, Robin L.; Beerman, Lori C.; Martus, Cameron; Lynch, David K.; Russell, Ray W.; Grady, Carol A.; Schneider, Glenn; Lisse, Carey M.; Nuth, Joseph A.; Cure, Michel; Henden, Arne A.; Kraus, Stefan; Motta, Veronica; Tamura Motohide; Hornbeck, Jeremy; Williger, Gerard M.; Fugazza, Dino</p> <p>2011-01-01</p> <p>We present thirteen epochs of near-infrared (0.8-5 microns) spectroscopic observations of the pre-transitional, "gapped" disk system in SAO 206462 (=HD 135344B). In all, six <span class="hlt">gas</span> emission lines (Br(alpha) , Br(gamma), Pa(beta), Pa(delta), Pa(epsilon), and the 0.8446 microns line of O I) along with continuum measurements made near the standard J, H, K, and L photometric bands were measured. A mass accretion rate of approximately 2 x 10(exp 8)Solar Mass/yr was derived from the Br(gamma) and Pa(beta) lines. However, the fluxes of these lines varied by a factor of over two during the course of a few months. The continuum also varied, but by only approx.30%, and even decreased at a time when the <span class="hlt">gas</span> emission was increasing. The H I line at 1.083 microns was also found to vary in a manner inconsistent with that of either the hydrogen lines or the dust. Both the <span class="hlt">gas</span> and dust variabilities indicate significant changes in the region of the inner <span class="hlt">gas</span> and the inner dust belt that may be common to many young disk systems. If planets are responsible for defining the inner edge of the gap, they could interact with the material on time scales commensurate with what is observed for the variations in the dust, while other disk instabilities (thermal, magneto-rotational) would operate there on longer time scales than we observe for the inner dust belt. For SAO 206462, the orbital period would likely be 1-3 years. If the changes are being induced in the disk material closer to the star than the gap, a variety of mechanisms (disk instabilities, interactions via planets) might be responsible for the changes seen. The He I feature is most likely due to a wind whose orientation changes with respect to the observer on time scales of a day or less. To further constrain the origin of the <span class="hlt">gas</span> and dust emission will require multiple spectroscopic and interferometric observations on both shorter and longer time scales that have been sampled so far.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/45171','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/45171"><span>Soil-<span class="hlt">gas</span> and indoor radon <span class="hlt">distribution</span> related to geology in Frederick County, Maryland</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Szarzi, S.L.; Reimer, G.M.; Been, J.M.</p> <p>1992-12-31</p> <p>Soil-<span class="hlt">gas</span> radon concentrations vary in response to geologic controls in Frederick County, Maryland, and the variation leads to different radon availabilities for potential indoor accumulations. Quartzites, which form from the core of ridges and mountains of the southern and western part of the county, have a mean soil-<span class="hlt">gas</span> radon concentration of 26 kBq m{sup -3} (700 pCi L{sup -1}). Phyllites, found in the Piedmont province in the eastern part of the county, have a mean soil-<span class="hlt">gas</span> radon concentration of 59 kBq m{sup -3} (1600 pCi L{sup -1}). Many indoor radon measurements for homes in the southeast portion of the county, made by means of charcoal canisters, exceeded 1850 Bq m{sup -3} (50 pCi L{sup -1}). Homes built in areas where the soil-<span class="hlt">gas</span> radon concentrations were greater than 75 kBq m{sup -3} (2000 pCi L{sup -1}) may have indoor radon concentrations that exceed 150 Bq m{sup -3} (4 pCi L{sup -1}), the current action level recommended by the U.S. Environmental Protection Agency. Data obtained in studies like ours throughout the United States are essential to identify {open_quotes}hot spots{close_quotes} which may produce elevated indoor radon levels of significant risk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/15020886','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/15020886"><span>Three-dimensional <span class="hlt">distribution</span> of <span class="hlt">gas</span> hydrate beneath southern Hydrate Ridge: constraints from ODP Leg 204</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Trehu, Ann M.; Long, Philip E.; Torres, M E.; Bohrmann, G; Rack, F R.; Collett, T S.; Goldberg, D S.; Milkov, A V.; Riedel, M; Schultheiss, P; Bangs, N L.; Barr, S R.; Borowski, W S.; Claypool, G E.; Delwiche, Mark E.; Dickens, G R.; Gracia, E; Guerin, G; Holland, M; Johnson, Jerry E.; Lee, Y J.; Liu, C S.; Su, X; Teichert, B; Tomaru, H; Vanneste, M; Watanabe, M; Weinberger, Jill L.</p> <p>2004-03-01</p> <p>Large uncertainties about the energy resource potential and role in global climate change of <span class="hlt">gas</span> hydrates result from uncertainty about how much hydrate is contained in marine sediments. During Leg 204 of the Ocean Drilling Program (ODP) to the accretionary complex of the Cascadia subduction zone, the entire <span class="hlt">gas</span> hydrate stability zone was sampled in contrasting geological settings defined by a 3D seismic survey. By integrating results from different methods, including several new techniques developed for Leg 204, we overcome the problem of spatial under-sampling inherent in robust methods traditionally used for estimating the hydrate content of cores and obtain a high-resolution, quantitative estimate of the total amount and spatial variability of <span class="hlt">gas</span> hydrate in this structural system. We conclude that high <span class="hlt">gas</span> hydrate content (30-40% of pore space of 20-26% of total volume) is restricted to the upper tens of meters below the seafloor near the summit of the structure, where vigorous fluid venting occurs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JTST...21..263C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JTST...21..263C"><span>Numerical Simulation of the Twin-Wire Arc Spraying Process: Modeling the High Velocity <span class="hlt">Gas</span> Flow Field <span class="hlt">Distribution</span> and Droplets Transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Yongxiong; Liang, Xiubing; Wei, Shicheng; Chen, Xi; Xu, Binshi</p> <p>2012-03-01</p> <p>During the twin-wire arc spraying, a high velocity <span class="hlt">gas</span> stream is used to accelerate the arc-melting materials and propel the droplets toward the substrate surface. This study is aimed at investigating the <span class="hlt">gas</span> flow formation and droplets transport processes using numerical simulation method. Results from the 3-D <span class="hlt">gas</span> flow field model show that the <span class="hlt">distribution</span> of the <span class="hlt">gas</span> flow velocity on the twin-wire intersection plane is quite different from that on the twin-wire vertical plane. Based on the 3-D model, the convergence amplitude of the high velocity zone in the jet center is improved by modifying the gun head design. It is also observed that a flat substrate existed downstream from the <span class="hlt">gas</span> nozzle exit results in decreasing close to zero in velocity of the <span class="hlt">gas</span> jet near the substrate. In addition, the predicted droplet trajectories and velocity <span class="hlt">distributions</span> exhibited good agreement with experimentally observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17512820','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17512820"><span>On-line purge and trap <span class="hlt">gas</span> chromatography for monitoring of trihalomethanes in drinking water <span class="hlt">distribution</span> systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Brown, Michael A; Miller, Sarah; Emmert, Gary L</p> <p>2007-06-05</p> <p>A method using an automated on-line purge and trap <span class="hlt">gas</span> chromatograph with a dry electrolytic conductivity detector (DELCD) has been developed for monitoring four regulated trihalomethanes in drinking water <span class="hlt">distribution</span> systems. This analyzer samples trihalomethanes from drinking water by pervaporation through a silicone capillary membrane contained within a <span class="hlt">gas</span> extraction cell (GEC) followed by preconcentration using an adsorbent trap. Trihalomethanes are subsequently desorbed from the trap onto a capillary column, separated and detected. The analyzer operates in real-time, samples directly from the drinking water <span class="hlt">distribution</span> system and is fully automated. The optimization, operation, and evaluation of the analyzer and method are discussed. Method detection limits (MDL) are less than 1.0 microg L(-1) with acceptable estimates for accuracy, and precision. The results from two on-line monitoring studies in chlorinated and chloraminated <span class="hlt">distribution</span> systems are presented. The performance of the method is compared directly to United Stated Environmental Protection Agency Method 502.2 and shows a very slight, but acceptable bias.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://me.water.usgs.gov/reports/mckinhpc.pdf','USGSPUBS'); return false;" href="http://me.water.usgs.gov/reports/mckinhpc.pdf"><span><span class="hlt">Distribution</span> of Trichloroethylene and Geologic Controls on Contaminant Pathways near the Royal River, McKin Superfund Site Area, Gray, <span class="hlt">Maine</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Lyford, Forest P.; Flight, L.E.; Stone, Janet Radway; Clifford, Scott</p> <p>1999-01-01</p> <p>Vapor-diffusion samplers were used in the autumn of 1997 to determine the lateral extent and <span class="hlt">distribution</span> of concentrations of a trichloroethylene (TCE) plume in the ground-water discharge area near the McKin Superfund Site, Gray, <span class="hlt">Maine</span>. Analyses of vapor in the samplers identified a plume about 800 feet wide entering the river near Boiling Springs, an area of ground-water discharge on the flood plain of the Royal River. The highest observed concentration of TCE in vapor was in an area of sand boils on the western bank of the river and about 200 feet downstream from Boiling Springs. Previous studies showed that most of the TCE load in the river originated in the area of the sand boils. In general, highest concentrations were observed on the western side of the river on the upgradient side of the plume, but TCE also was detected at numerous locations in the center and eastern bank of the river. The TCE plume discharges to the river where fine-grained glaciomarine sediments of the Presumpscot Formation are absent and where coarse-grained facies of buried glaciomarine fan deposits provide a pathway for ground-water flow. Based on results of analyses of vapor-diffusion samples and other previous studies, the plume appears to pass under and beyond the river near Boiling Springs and along the river for about 300 feet downstream from the sand boils. A coarse-grained, organic-rich layer at the base of the alluvial flood plain sediments is confined by overlying fine-grained alluvial sediments and may provide a conduit for ground-water leaking upward from buried glaciomarine fan deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920011435','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920011435"><span>Simulation of real-<span class="hlt">gas</span> effects on pressure <span class="hlt">distributions</span> for aeroassist flight experiment vehicle and comparison with prediction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Micol, John R.</p> <p>1992-01-01</p> <p>Pressure <span class="hlt">distributions</span> measured on a 60 degree half-angle elliptic cone, raked off at an angle of 73 degrees from the cone centerline and having an ellipsoid nose (ellipticity equal to 2.0 in the symmetry plane) are presented for angles of attack from -10 degrees to 10 degrees. The high normal shock density ratio aspect of a real <span class="hlt">gas</span> was simulated by testing in Mach 6 air and CF sub 4 (density ratio equal to 5.25 and 12.0, respectively). The effects of Reynolds number, angle of attack, and normal shock density ratio on these measurements are examined, and comparisons with a three dimensional Euler code known as HALIS are made. A significant effect of density ratio on pressure <span class="hlt">distributions</span> on the cone section of the configuration was observed; the magnitude of this effect decreased with increasing angle of attack. The effect of Reynolds number on pressure <span class="hlt">distributions</span> was negligible for forebody pressure <span class="hlt">distributions</span>, but a measurable effect was noted on base pressures. In general, the HALIS code accurately predicted the measured pressure <span class="hlt">distributions</span> in air and CF sub 4.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JPS...271...16K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JPS...271...16K"><span>Improvement of oxygen diffusion characteristic in <span class="hlt">gas</span> diffusion layer with planar-<span class="hlt">distributed</span> wettability for polymer electrolyte fuel cell</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koresawa, Ryo; Utaka, Yoshio</p> <p>2014-12-01</p> <p>Mass transfer characteristics of <span class="hlt">gas</span> diffusion layer (GDL) are closely related to performance of polymer electrolyte fuel cells. Therefore, it is necessary to clarify the characteristics of water <span class="hlt">distribution</span> relating to the microscopic conformation and oxygen diffusivity of GDL. A hybrid type carbon paper GDL with planar-<span class="hlt">distributed</span> wettability is investigated for control of liquid water movement and <span class="hlt">distribution</span> due to hydrophobic to hydrophilic areas that provide wettability differences in GDL and to achieve enhancement of both oxygen diffusion and moisture retention. Hybrid GDLs with different PTFE content were fabricated in an attempt to improve the oxygen diffusion characteristics. The effects of different PTFE contents on the oxygen diffusivity and water <span class="hlt">distribution</span> were simultaneously measured and observed using galvanic cell oxygen absorber and X-ray radiography. The PTFE <span class="hlt">distribution</span> was observed using scanning electron microscopy. The formation of oxygen diffusion paths was confirmed by X-ray radiography, where voids in the hybrid GDL were first formed in the hydrophobic regions and then spread to the untreated wetting region. Thus, the formation of oxygen diffusion paths enhanced the oxygen diffusion. In addition, the effects of local PTFE content in the hydrophobic region and the optimal amount of PTFE for hybrid GDL were elucidated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JGR...103..439M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JGR...103..439M"><span>SPEAR 3 flight analysis: Grounding by neutral <span class="hlt">gas</span> release, and magnetic field effects on current <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mandell, M. J.; Jongeward, G. A.; Cooke, D. L.; Raitt, W. J.</p> <p>1998-01-01</p> <p>The Space Power Experiment Aboard Rockets (SPEAR) 3 experiment was launched on March 15, 1993, to test grounding devices for negative payloads. In this paper we review two aspects of the high-altitude flight data and compare them with preflight predictions. The SPEAR 3 neutral <span class="hlt">gas</span> release experiment studied a grounding mechanism observed on previous flights during attitude control system (ACS) firings. Preflight calculations using Paschen law physics generalized to three dimensions predicted that the high rate <span class="hlt">gas</span> release (about one order of magnitude below normal ACS) would reduce the rocket potential to within 200-300 V of plasma ground. The flight data is well fit by a value of -225V. Orientation relative to Earth's magnetic field had no effect on the floating potential or grounding operations but had a large effect on the portion of the current collected by the boom. We compare these flight measurements with preflight calculations made with the DynaPAC computer code.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2258544A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2258544A"><span>Witnessing <span class="hlt">Gas</span> Mixing in the Metal <span class="hlt">Distribution</span> during a Galaxy Merger.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amram, Philippe</p> <p>2015-08-01</p> <p>I will present direct evidence that in a merger of disk galaxies, the pre-existing central metallicities will mix as a result of <span class="hlt">gas</span> being transported in the merger interface region along the line that joins the two coalescing nuclei. In focusing on the emission line <span class="hlt">gas</span>, this is shown using detailed two-dimensional kinematics as well as metallicity measurements for the nearby ongoing merger in the center of the compact group HCG 31. The two coalescing cores display similar oxygen abundances, while in between the two nuclei, the metallicity changes smoothly from one nucleus to the other indicating a mix of metals in this region. This nearby system involves the merging of two fairly low-mass and clumpy galaxies (LMC-like galaxies), making it an important system for comparison with high-redshift galaxies.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA555294','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA555294"><span>Running on Fumes: A Critical Look at Mexico’s Natural <span class="hlt">Gas</span> Transportation and <span class="hlt">Distribution</span> Infrastructure</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2011-10-27</p> <p>behind existing laws and policies that are hampering growth and development in Mexico’s petrochemical industry. 3 Petroleos Mexicanos ( PEMEX ...is the state-owned company created in 1938 to run the national oil and natural <span class="hlt">gas</span> monopoly. In the decades that followed, PEMEX often utilized...privatization of PEMEX and its subsidiaries. The PRD has proposed an alternate plan, developed by founding PRD member 4 and adviser to the National</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MMTB...48...17C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MMTB...48...17C"><span>Mixing and Residence Time <span class="hlt">Distribution</span> in an Inert <span class="hlt">Gas</span>-Shrouded Tundish</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chatterjee, Saikat; Asad, Amjad; Kratzsch, Christoph; Schwarze, Rüdiger; Chattopadhyay, Kinnor</p> <p>2017-02-01</p> <p>Tracer dispersion experiments were carried out in a multi-strand tundish by injecting 1 (N) NaCl solution into water. The variation of dimensionless concentration-time curves known as C-curves and mixing times with different <span class="hlt">gas</span> flow rates were studied. The proportions of dead, mixed, and dispersed plug volumes were calculated using the `modified mixed model.' The observations were explained by analyzing the behavior of the bubble plume, incoming jet velocity, and turbulent kinetic energy within the tundish.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997AJ....114..946M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997AJ....114..946M"><span>Spatial <span class="hlt">distribution</span> of far-infrared emission in spiral galaxies. II. Heating sources and <span class="hlt">gas</span>-to-dust ratio.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mayya, Y. D.; Rengarajan, T. N.</p> <p>1997-09-01</p> <p>We study the radial <span class="hlt">distribution</span> of the temperature of the warm dust and <span class="hlt">gas</span>-to-dust mass ratios in a sample of 22 spiral galaxies. The heating capabilities of the diffuse interstellar radiation field (ISRF), based on Desert et al. model, are investigated in 13 of the sample galaxies. In general, the temperature of the warm dust decreases away from the center, reaches a minimum value at the mid-disk and increases again in the outer parts of galaxies. Heating a mixture of small and big grains by the ISRF is able to explain the observed behavior qualitatively. However, ultraviolet photons from recent star formation events are necessary for a detailed matching of the warm dust temperature profiles. Very small grains contribute typically more than 50% to the observed flux at 60 microns beyond half the disk radius in galaxies. Optical depth ( tausixty) profiles, derived from the observed 60 microns and warm dust temperature profiles, peak at or close to the galactic center. In 13 of the galaxies, where dust temperature profiles are modeled, we obtain optical depth and dust mass profiles after correction for the contaminating effects of very small grains. These profiles are combined with the <span class="hlt">gas</span> density profiles in the literature, to generate profiles of the <span class="hlt">gas</span>-to-dust mass ratio. The resulting <span class="hlt">gas</span>-to-dust mass ratio decreases by a factor of 8 from the center to the optical isophotal radius, where the value approaches the local galactic value. With the understanding that the dust mass is proportional to metallicity, and that the metallicity increases towards the center of galaxies, one expects the <span class="hlt">gas</span>-to-dust ratio to decrease towards the center, contrary to what is observed. We demonstrate that the observed steep gradient is a result of the over-estimation of the molecular mass, and can be flattened out to within a factor of 2, if the molecular hydrogen mass is recomputed assuming a metallicity dependent conversion factor from CO intensity to {h two} column density</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..DMP.J9007B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..DMP.J9007B"><span>Measurements of the ion velocity <span class="hlt">distribution</span> in an ultracold neutral plasma derived from a cold, dense Rydberg <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bergeson, Scott; Lyon, Mary</p> <p>2016-05-01</p> <p>We report measurements of the ion velocity <span class="hlt">distribution</span> in an ultracold neutral plasma derived from a dense, cold Rydberg <span class="hlt">gas</span> in a MOT. The Rydberg atoms are excited using a resonant two-step excitation pathway with lasers of 4 ns duration. The plasma forms spontaneously and rapidly. The rms width of the ion velocity <span class="hlt">distribution</span> is determined by measuring laser-induced fluorescence (LIF) of the ions. The measured excitation efficiency is compared with a Monte-Carlo wavefunction calculation, and significant differences are observed. We discuss the conditions for blockaded Rydberg excitation and the subsequent spatial ordering of Rydberg atom domains. While the blockade interaction is greater than the Rabi frequency in portions of the atomic sample, no evidence for spatial ordering is observed. This research is supported in part by the Air Force Office of Scientific Research (Grant No. FA9950-12- 0308) and by the National Science Foundation (Grant No. PHY-1404488).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1614258M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1614258M"><span>Mapping <span class="hlt">distribution</span> and thickness of supraglacial debris in the Central Karakoram National Park: <span class="hlt">main</span> features and implications to model glacier meltwater</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Minora, Umberto; Mayer, Christoph; Bocchiola, Daniele; D'Agata, Carlo; Maragno, Davide; Lambrecht, Astrid; Vuillermoz, Elisa; smiraglia, claudio; diolaiuti, guglielmina</p> <p>2014-05-01</p> <p>Supraglacial debris plays a not negligible role in controlling magnitude and rates of buried ice melt (Østrem, 1959; Mattson et al., 1993). Knowledge on rock debris is essential to model ice melt (and consequently meltwater discharge) upon wide glacierized areas, as melt rates are <span class="hlt">mainly</span> driven by debris thickness variability. This is particularly important for the Pamir-Himalaya-Karakoram area (PHK), where debris-covered glaciers are frequent (Smiraglia et al., 2007; Scherler et al., 2011) and where melt water from glaciers supports agriculture and hydropower production. By means of remote sensing techniques and field data, supraglacial debris can be detected, and then quantified in area and thickness. Supervised classifications of satellite imagery can be used to map debris on glaciers. They use different algorithms to cluster an image based on its pixel values, and Region Of Interests (ROIs) previously selected by the human operator. This can be used to obtain a supraglacial debris mask by which surface extension can be calculated. Moreover, kinetic surface temperature data derived from satellites (such as ASTER and Landsat), can be used to quantify debris thicknesses (Mihalcea et al., 2008). Ground Control Points (GCPs) are essential to validate the obtained debris thicknesses. We took the Central Karakoram National Park (CKNP) as a representative sample for PHK area. The CKNP is 12,000 km2 wide, with more than 700 glaciers, mostly debris covered (Minora et al., 2013). Among those we find some of the widest glaciers of the World (e.g: Baltoro). To improve the knowledge on these glaciers and to better model their melt and water discharge we proceeded as follows. Firstly we ran a Supervised Maximum Likelihood (SML) classification on 2001 and 2010 Landsat images to detect debris presence and <span class="hlt">distribution</span>. Secondly we analyzed kinetic surface temperature (from Landsat) to map debris depth. This latter attempt took also advantage from field data of debris thickness</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003SedG..163..147H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003SedG..163..147H"><span>Deev Jahi Model of the Permian Triassic boundary mass extinction: a case for <span class="hlt">gas</span> hydrates as the <span class="hlt">main</span> cause of biological crisis on Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heydari, E.; Hassanzadeh, J.</p> <p>2003-12-01</p> <p>The smoking gun revealing the secrets of the end-Permian mass mortality is a unique 1-2-m-thick layer consisting of 5-20-cm-long crystals of calcite that occurs precisely at the Permian-Triassic boundary (PTB) in Iran, Armenia, Turkey, and China. This layer is interpreted as synsedimentary, abiotic, seafloor cement indicative of precipitation from a highly carbonate supersaturated seawater. Its δ13C composition ( δ13C=0‰ PDB) is 4‰ to 5‰ PDB lower than the typical Upper Permian values (4‰ to 5‰ PDB), suggesting the involvement of massive amounts of <span class="hlt">gas</span> hydrate CH 4 ( δ13C=-60‰ PDB). The temporal coincidence of the cement layer with the PTB suggests that the process that promoted seafloor cementation was also responsible for the biological crisis. A cementation model is developed based on accumulation-dissociation cycle of <span class="hlt">gas</span> hydrates which also explains the mass extinction at the PTB. The Upper Permian accumulation period of <span class="hlt">gas</span> hydrates ended abruptly adjacent to the PTB and the dissociation event began releasing 3.2 to 4.7×10 18 g CH 4 into the ocean. Oxidation of CH 4 in the water column created a seawater that was charged with CO 2 (an oceanic acid bath) and had lower than normal O 2 content (but not anoxic). This oceanic acid bath first dissolved suspended fine-grained carbonate particles and small calcareous organisms, followed by extensive dissolution of platform carbonates raising Ca 2+ and HCO 3- concentrations of seawater. When the release of CH 4 declined, the acid-bath ocean became a soda ocean precipitating massive amount of seafloor cements observed globally at the PTB. The study suggests that prior to cement precipitation, the PTB ocean was charged with CO 2, warm, had low oxygen, high Ca 2+, and high HCO 3- concentrations. These conditions collectively created stressful conditions causing the marine mass mortality. The leakage of CH 4 to the atmosphere produced a super-hot climate resulting in the biological devastation on land. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23890655','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23890655"><span>Molecularly imprinted solid phase extraction for simultaneous determination of Δ9-tetrahydrocannabinol and its <span class="hlt">main</span> metabolites by <span class="hlt">gas</span> chromatography-mass spectrometry in urine samples.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nestić, Marina; Babić, Sandra; Pavlović, Dragana Mutavdžić; Sutlović, Davorka</p> <p>2013-09-10</p> <p>In presented paper analytical method based on solid-phase extraction using molecularly imprinted polymer and <span class="hlt">gas</span> chromatography-mass spectrometry has been developed and validated for the confirmation of THC, THC-OH and THC-COOH in urine samples. Non-covalent molecularly imprinted polymers of THC-OH were prepared using different functional monomers (methacrylic acid, 4-vinylpyridine, and 2-hydroxyethyl methacrylate), ethylene glycol dimethacrylate as a cross-linker and 2,2'-azobis-isobutyronitrile as an initiator of radical polymerization. Analytes were extracted from urine samples using prepared polymer sorbent with highest binding selectivity and capability. Before extraction, urine samples were hydrolyzed with alkaline. Elution was performed with chloroform:ethyl acetate (60:40, v/v). Dry extracts were silylated with BSTFA+1% TMCS. Detection and quantification were performed using <span class="hlt">gas</span> chromatography-mass spectrometry in single ion recording mode. The developed method was linear over the range from LOQ to 150 ng mL(-1) for all three analytes. For THC, THC-OH and THC-COOH LOD was 2.5, 1 and 1 ng mL(-1), and LOQ was 3, 2 and 2 ng mL(-1), respectively. The precision, accuracy, recovery and matrix effect were investigated at 5, 25 and 50 ng mL(-1). In the investigated concentration range recoveries were 71.9% for THC, 78.6% for THC-OH and 75.2% for THC-COOH. Matrix effect was not significant (<10%) for all analytes in the concentration range from 5 ng mL(-1) to 50 ng mL(-1). Extraction recovery on non-imprinted polymer was relatively high indicating high non-specific binding. Optimized and validated method was applied to 15 post-mortem urine samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011TRACE..22..335S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011TRACE..22..335S"><span>Optimum Operation Condition on <span class="hlt">Distributed</span> Power Supply System with Micro <span class="hlt">Gas</span> Turbine/Solid Oxide Fuel Cell</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Suzuki, Hiroshi; Yamada, Miki; Usui, Hiromoto; Komoda, Yoshiyuki</p> <p></p> <p>In order to find the optimum operation condition of a <span class="hlt">distributed</span> power supply system of 30kW class micro <span class="hlt">gas</span> turbine (MGT) and solid oxide fuel cell (SOFC) hybrid system with the combination of line electric power and supplied <span class="hlt">gas</span>, a system analysis has been performed. In this study, an absorption chiller and a boiler were mounted to utilize the exhausted heat from the MGT/SOFC system. The time variation of energy consumption in 24 hours for house and market models was taken into consideration for the calculation of the energy saving ratio of the present system. The operation ratio defined with the ratio of power supply of MGT/SOFC system to the power required at the peak load was changed as a parameter. From the comparison with the system using line power and <span class="hlt">gas</span>, it is found that the present system shows high energy saving ratio around 0.4 of the operation ratio, but the energy saving ratio severely decreases in the range of high operation ratio. In this study, it is revealed that the thermal storage system effectively improves the energy saving ratio especially for the house model in winter season.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993AAS...18311601L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993AAS...18311601L"><span>Shadowing of the Soft X-ray Background and the <span class="hlt">Distribution</span> of Hot <span class="hlt">Gas</span> in the Local Interstellar Medium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Labov, Simon E.; Craig, William W.; Kahn, Steven M.</p> <p>1993-12-01</p> <p>The underlying mechanism responsible for variations in the observed 1/4 keV X-ray background is not well understood. Measurements of soft X-ray shadows cast by clumps of neutral material provide a direct method of determining the spatial <span class="hlt">distribution</span> of the hot <span class="hlt">gas</span> responsible for the soft X-ray background. The observed contrast of an X-ray shadow depends on the density and size of the cool absorbing cloud, and on the amount of foreground and background soft X-ray emitting <span class="hlt">gas</span>. We present here a dramatic example of this shadowing effect as observed by the ROSAT X-ray telescope and position sensitive proportional counter (PSPC). The shadow discussed here is particularly dark with high contrast indicating that the vast majority of the X-ray emitting <span class="hlt">gas</span> in this direction extends beyond the cloud. This work was supported by the NASA ROSAT Guest Observer Program under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. W-7405-ENG-48.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100036217','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100036217"><span>Transition in <span class="hlt">Gas</span> Turbine Control System Architecture: Modular, <span class="hlt">Distributed</span>, and Embedded</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Culley, Dennis</p> <p>2010-01-01</p> <p>Controls systems are an increasingly important component of turbine-engine system technology. However, as engines become more capable, the control system itself becomes ever more constrained by the inherent environmental conditions of the engine; a relationship forced by the continued reliance on commercial electronics technology. A revolutionary change in the architecture of turbine-engine control systems will change this paradigm and result in fully <span class="hlt">distributed</span> engine control systems. Initially, the revolution will begin with the physical decoupling of the control law processor from the hostile engine environment using a digital communications network and engine-mounted high temperature electronics requiring little or no thermal control. The vision for the evolution of <span class="hlt">distributed</span> control capability from this initial implementation to fully <span class="hlt">distributed</span> and embedded control is described in a roadmap and implementation plan. The development of this plan is the result of discussions with government and industry stakeholders</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.1405D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.1405D"><span><span class="hlt">Gas</span> hydrate <span class="hlt">distribution</span> and hydrocarbon maturation north of the Knipovich Ridge, western Svalbard margin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dumke, Ines; Burwicz, Ewa B.; Berndt, Christian; Klaeschen, Dirk; Feseker, Tomas; Geissler, Wolfram H.; Sarkar, Sudipta</p> <p>2016-03-01</p> <p>A bottom-simulating reflector (BSR) occurs west of Svalbard in water depths exceeding 600 m, indicating that <span class="hlt">gas</span> hydrate occurrence in marine sediments is more widespread in this region than anywhere else on the eastern North Atlantic margin. Regional BSR mapping shows the presence of hydrate and free <span class="hlt">gas</span> in several areas, with the largest area located north of the Knipovich Ridge, a slow spreading ridge segment of the Mid Atlantic Ridge system. Here heat flow is high (up to 330 mW m-2), increasing toward the ridge axis. The coinciding maxima in across-margin BSR width and heat flow suggest that the Knipovich Ridge influenced methane generation in this area. This is supported by recent finds of thermogenic methane at cold seeps north of the ridge termination. To evaluate the source rock potential on the western Svalbard margin, we applied 1-D petroleum system modeling at three sites. The modeling shows that temperature and burial conditions near the ridge were sufficient to produce hydrocarbons. The bulk petroleum mass produced since the Eocene is at least 5 kt and could be as high as ~0.2 Mt. Most likely, source rocks are Miocene organic-rich sediments and a potential Eocene source rock that may exist in the area if early rifting created sufficiently deep depocenters. Thermogenic methane production could thus explain the more widespread presence of <span class="hlt">gas</span> hydrates north of the Knipovich Ridge. The presence of microbial methane on the upper continental slope and shelf indicates that the origin of methane on the Svalbard margin varies spatially.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/15082059','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/15082059"><span><span class="hlt">Distribution</span> of radium in oil and <span class="hlt">gas</span> industry wastes from Malaysia.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Omar, M; Ali, H M; Abu, M P; Kontol, K M; Ahmad, Z; Ahmad, S H S S; Sulaiman, I; Hamzah, R</p> <p>2004-05-01</p> <p>Radium concentrations in 470 samples of the various types of waste from oil and <span class="hlt">gas</span> industries were analysed using gamma spectrometers. The results showed that the radium concentration varied within a wide range. The highest mean 226Ra and 228Ra concentrations of 114,300 and 130,120 Bq/kg, respectively, were measured in scales. Overall, 75% of the waste, mostly sludge and extraction residue lies within the normal range of radium concentration in soils of Malaysia. However, some platform sludge can have radium concentration up to 560 Bq/kg.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MeScT..24g4003Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MeScT..24g4003Z"><span>A novel ECT-EST combined method for <span class="hlt">gas</span>-solids flow pattern and charge <span class="hlt">distribution</span> visualization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, B.; Zhang, J. Y.</p> <p>2013-07-01</p> <p>A non-invasive measurement method of visualizing the flow pattern and charge <span class="hlt">distribution</span> of <span class="hlt">gas</span>-solids two-phase flow has been studied and verified using gravity-dropping and pneumatic conveyance rigs with pulverized coal as solids. It has been proven that the permittivity <span class="hlt">distribution</span> acquired from an electrical capacitance tomography (ECT) system can be used to improve the accuracy in establishing charge sensitivity field of an electrostatic tomography (EST) system, and to reduce the uncertainty of charge <span class="hlt">distribution</span> reconstruction. The experimental results show that, under the given experimental conditions for the gravity-dropping system, charge density increases with particles' concentration, whilst in the pneumatic conveyance system, charge density decreases in the area where the particles' concentration is higher, and the total charge intensity decreases with the increase of the concentration of pulverized coal in the pipe. The method proposed in this paper is potentially important in pneumatic processes for charge <span class="hlt">distribution</span> measurement and safe operations. It is envisaged that with further development, this technique can provide information for investigation into the mechanism of inter-particle force on electrostatic attraction and repulsion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.mayoclinic.org/diseases-conditions/gas-and-gas-pains/basics/definition/CON-20019271?p=1','NIH-MEDLINEPLUS'); return false;" href="http://www.mayoclinic.org/diseases-conditions/gas-and-gas-pains/basics/definition/CON-20019271?p=1"><span><span class="hlt">Gas</span> and <span class="hlt">Gas</span> Pains</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... your <span class="hlt">gas</span> and bloating occur <span class="hlt">mainly</span> after eating dairy products, it may be because your body isn' ... able to break down the sugar (lactose) in dairy foods. Other food intolerances, especially to gluten — a ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JPS...160.1041Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JPS...160.1041Z"><span>Effects of porosity <span class="hlt">distribution</span> variation on the liquid water flux through <span class="hlt">gas</span> diffusion layers of PEM fuel cells</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhan, Zhigang; Xiao, Jinsheng; Li, Dayong; Pan, Mu; Yuan, Runzhang</p> <p></p> <p>Flooding of the membrane electrode assembly (MEA) and dehydrating of the polymer electrolyte membrane have been the key problems to be solved for polymer electrolyte membrane fuel cells (PEMFCs). So far, almost no papers published have focused on studies of the liquid water flux through differently structured <span class="hlt">gas</span> diffusion layers (GDLs). For <span class="hlt">gas</span> diffusion layers including structures of uniform porosity, changes in porosity (GDL with microporous layer (MPL)) and gradient change porosity, using a one-dimensional model, the liquid saturation <span class="hlt">distribution</span> is analyzed based on the assumption of a fixed liquid water flux through the GDL. And then the liquid water flux through the GDL is calculated based on the assumption of a fixed liquid saturation difference between the interfaces of the catalyst layer/GDL and the GDL/<span class="hlt">gas</span> channel. Our results show that under steady-state conditions, the liquid water flux through the GDL increases as contact angle and porosity increase and as the GDL thickness decreases. When a MPL is placed between the catalyst layer and the GDL, the liquid saturation is redistributed across the MPL and GDL. This improves the liquid water draining performance. The liquid water flux through the GDL increases as the MPL porosity increases and the MPL thickness decreases. When the total thickness of the GDL and MPL is kept constant and when the MPL is thinned to 3 μm, the liquid water flux increases considerably, i.e. flooding of MEA is difficult. A GDL with a gradient of porosity is more favorable for liquid water discharge from catalyst layer into the <span class="hlt">gas</span> channel; for the GDLs with the same equivalent porosity, the larger the gradient is, the more easily the liquid water is discharged. Of the computed cases, a GDL with a linear porosity 0.4 x + 0.4 is the best.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22364714','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22364714"><span>WITNESSING <span class="hlt">GAS</span> MIXING IN THE METAL <span class="hlt">DISTRIBUTION</span> OF THE HICKSON COMPACT GROUP HCG 31</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Torres-Flores, S.; Alfaro-Cuello, M.; De Oliveira, C. Mendes; Amram, P.; Carrasco, E. R.</p> <p>2015-01-01</p> <p>We present for the first time direct evidence that in a merger of disk galaxies, the pre-existing central metallicities will mix as a result of <span class="hlt">gas</span> being transported in the merger interface region along the line that joins the two coalescing nuclei. This is shown using detailed two-dimensional kinematics as well as metallicity measurements for the nearby ongoing merger in the center of the compact group HCG 31. We focus on the emission line <span class="hlt">gas</span>, which is extensive in the system. The two coalescing cores display similar oxygen abundances. While in between the two nuclei, the metallicity changes smoothly from one nucleus to the other indicating a mix of metals in this region, which is confirmed by the high-resolution Hα kinematics (R = 45,900). This nearby system is especially important because it involves the merging of two fairly low-mass and clumpy galaxies (LMC-like galaxies), making it an important system for comparison with high-redshift galaxies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5903730','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5903730"><span><span class="hlt">Distribution</span> of <span class="hlt">gas</span>-oil-bitumen shows in the Yakutian diamond province</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kravtsov, A.I.; Ivanov, V.A.; Bobrov, V.A.; Kropotova, O.I.</p> <p>1981-10-01</p> <p>The combination of carbon-bearing compounds in the kimberlite pipes may be divided into distinct geochemical groups, genetically associated with exogenic or endogenic geological processes. In analyzing the isotope composition of diamonds from eclogite and kimberlite, graphite in concentrated form from eclogite and ultrabasic inclusions in kimberlite, and postmagmaic carbonic acid from the matrix of kimberlite, it was established that these compounds have a distinctive endogenic nature. The isotope composition of the limestones of marine origin has been determined by the isotope-exchange reation /sup 13/CO/sub 2/ (<span class="hlt">gas</span>) + /sup 12/CO/sub 3/ (solution) reverse arrow..-->.. /sup 12/CO/sub 2/ (<span class="hlt">gas</span>) + /sup 13/CO/sub 3/ (solution), which is rigidly associated with temperature of sedimentation and has controlled the ''heavy'' isotope composition of these rocks. The isotope composition of the bitumens has not yet enabled us to resolve the problem of the origin of the bitumen shows (biogenic or abiogenic). However, the similarity of the isotope composition of bitumens examined from various bitumen shows indicates identical thermodynamic conditions of formation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/publication/?seqNo115=319230','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/publication/?seqNo115=319230"><span><span class="hlt">Distribution</span> and chemical fate of chlorine dioxide <span class="hlt">gas</span> during sanitation of tomatoes and cantaloupe</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>A series of studies was conducted to establish the 1) <span class="hlt">distribution</span> and chemical fate of 36-ClO2 on tomatoes and cantaloupe; and 2) the magnitude of residues in kilogram quantities of tomatoes and cantaloupe sanitized with a slow-release chlorine dioxide formulation. Tomatoes and cantaloupe were resp...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810020989','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810020989"><span>Evaluation of <span class="hlt">distributed</span> <span class="hlt">gas</span> cooling of pressurized PAFC for utility power generation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farooque, M.; Maru, H.; Skok, A.</p> <p>1981-01-01</p> <p>Two short stacks were pressure tested at 446 kPa (4.4 atm.) and the pressure gains were more than the theoretically predicted gains. Temperature profiles were observed to be independent of operating pressure. The pressure drop was found to be inversely proportional to operating pressure as expected. Continuous pressurized operation of a stack for 1000 hours verified the compatability of the fuel cell component design. A simple pressurization procedure was also developed. Six separate designs, covering two <span class="hlt">gas</span> cooling schemes (DIGAS and separated) and two cooling channel geometries (straight through and treed), were analysed on the net voltage output basis. Separated cooling with 5 cells per cooler was recognized to be the best among the designs considered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860019349','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860019349"><span>Element <span class="hlt">distribution</span> and noble <span class="hlt">gas</span> isotopic abundances in lunar meteorite Allan Hills A81005</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kraehenbuehl, U.; Eugster, O.; Niedermann, S.</p> <p>1986-01-01</p> <p>Antarctic meteorite ALLAN HILLS A81005, an anorthositic breccia, is recognized to be of lunar origin. The noble gases in this meteorite were analyzed and found to be solar-wind implanted gases, whose absolute and relative concentrations are quite similar to those in lunar regolith samples. A sample of this meteorite was obtained for the analysis of the noble <span class="hlt">gas</span> isotopes, including Kr(81), and for the determination of the elemental abundances. In order to better determine the volume derived from the surface correlated gases, grain size fractions were prepared. The results of the instrumental measurements of the gamma radiation are listed. From the amounts of cosmic ray produced noble gases and respective production rates, the lunar surface residence times were calculated. It was concluded that the lunar surface time is about half a billion years.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5955178','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5955178"><span><span class="hlt">Distribution</span> of <span class="hlt">gas</span> and galaxies around the distant quasar PKS 1614 + 051</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hu, E.M.; Cowie, L.L.</p> <p>1987-06-01</p> <p>The results of narrow-band and broad-band filter observations of the region surrounding the z = 3.21 quasars, PKS 1614 + 051, made under subarcsec seeing conditions with the 3.6 m CFHT telescope at Mauna Kea are reported. The nuclear region of the Lyman-alpha companion to the quasar is resolved with a FWHM of about 0.9 arcsec A magnitude fainter. Limits on detectable continuum flux from this object suggest that it is a <span class="hlt">gas</span> cloud interacting with the quasar, and its emission is consistent with simple photoionization by the quasar. However, the presence of several galaxies around the periphery of the quasar is noted. A search of 11 additional quasars at z greater than 3 has failed to show any other such systems. It is argued that this is consistent with the statistics of extended emission line systems in low-z quasars. 11 references.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21894765','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21894765"><span>[<span class="hlt">Main</span> pharmacokinetic parameters of p-tyrosol after intravenous injection in rats. Part III: <span class="hlt">Distribution</span> of p-tyrosol in rat].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chernyshova, G A; Plotnikov, M B; Smol'iakova, V I; Krasnov, E A</p> <p>2011-01-01</p> <p><span class="hlt">Distribution</span> of p-tyrosol in organism was studied in rats after a single intravenous administration in a dose of 200 mg/kg. It was shown that p-tyrosol rapidly penetrates into well perfused organs (brain, heart, kidneys). The maximum concentration ofp-tyrosol in these organs was determined in 1 minute after administration, and the mean <span class="hlt">distribution</span> constant was within 0.8-1.11. The albumin bound fraction ofp-tyrozol amounted to 0.26-0.30.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10162133','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10162133"><span>Risk analysis of highly combustible <span class="hlt">gas</span> storage, supply, and <span class="hlt">distribution</span> systems in PWR plants</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Simion, G.P.; VanHorn, R.L.; Smith, C.L.; Bickel, J.H.; Sattison, M.B.; Bulmahn, K.D.</p> <p>1993-06-01</p> <p>This report presents the evaluation of the potential safety concerns for pressurized water reactors (PWRs) identified in Generic Safety Issue 106, Piping and the Use of Highly Combustible Gases in Vital Areas. A Westinghouse four-loop PWR plant was analyzed for the risk due to the use of combustible gases (predominantly hydrogen) within the plant. The analysis evaluated an actual hydrogen <span class="hlt">distribution</span> configuration and conducted several sensitivity studies to determine the potential variability among PWRs. The sensitivity studies were based on hydrogen and safety-related equipment configurations observed at other PWRs within the United States. Several options for improving the hydrogen <span class="hlt">distribution</span> system design were identified and evaluated for their effect on risk and core damage frequency. A cost/benefit analysis was performed to determine whether alternatives considered were justifiable based on the safety improvement and economics of each possible improvement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/12071654','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/12071654"><span>Prediction of acute toxicity of chemicals in mixtures: worms Tubifex tubifex and <span class="hlt">gas</span>/liquid <span class="hlt">distribution</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tichý, M; Borek-Dohalský, V; Matousová, D; Rucki, M; Feltl, L; Roth, Z</p> <p>2002-03-01</p> <p>The aim of this contribution is to support our proposal of the procedure for predicting acute toxicity of binary mixtures by QSAR analysis techniques. The changes of a mixture composition are described by molar ratio R and visualized in the R-plot (QCAR--quantitative composition-activity relationships). The approach was inspired by Rault and Dalton's laws, their positive and negative deviations in the behavior of a mixture of real gases, by Loewe and Muischnek isoboles and by the Finney test of additivity. Acute toxicity was determined by the laboratory test with woms Tubifex tubifex. The additivity of the acute toxicity in the binary mixture benzene + nitrobenzene was confirmed and a new interaction is described: "mixed interaction" with the binary mixture aniline + ethanol. The "mixed interaction" means that depending on mixture composition, both potentiation and inhibition can occur. As the first physicochemical descriptor of the changes caused by the changing composition of binary mixtures, the <span class="hlt">gas</span>/liquid equilibrium was studied and a composition of the gaseous phase was determined by a <span class="hlt">gas</span> chromatographic method. The method for determination of concentrations in the gaseous phase was described. The gaseous phase composition of benzene + nitrobenzene. benzene + ethanol, benzene + aniline and ethanol + aniline mixtures was analyzed. It was found that if the concentrations of the mixture's components in the gaseous phase behave nonideally (they are not additive), the acute toxicity of the same mixture is not additive as well. Another descriptor to distinguish between potentiation and inhibition will be, however, necessary. The properties, both gaseous phase composition and the acute toxicity, of the benzene + nitrobenzene mixture are additive. In mixtures with the mixed interaction, the R-plot of the composition of the gaseous phase is complex with a large variation of results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...798L..24T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...798L..24T"><span>Witnessing <span class="hlt">Gas</span> Mixing in the Metal <span class="hlt">Distribution</span> of the Hickson Compact Group HCG 31</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Torres-Flores, S.; Mendes de Oliveira, C.; Amram, P.; Alfaro-Cuello, M.; Carrasco, E. R.; de Mello, D. F.</p> <p>2015-01-01</p> <p>We present for the first time direct evidence that in a merger of disk galaxies, the pre-existing central metallicities will mix as a result of <span class="hlt">gas</span> being transported in the merger interface region along the line that joins the two coalescing nuclei. This is shown using detailed two-dimensional kinematics as well as metallicity measurements for the nearby ongoing merger in the center of the compact group HCG 31. We focus on the emission line <span class="hlt">gas</span>, which is extensive in the system. The two coalescing cores display similar oxygen abundances. While in between the two nuclei, the metallicity changes smoothly from one nucleus to the other indicating a mix of metals in this region, which is confirmed by the high-resolution Hα kinematics (R = 45,900). This nearby system is especially important because it involves the merging of two fairly low-mass and clumpy galaxies (LMC-like galaxies), making it an important system for comparison with high-redshift galaxies. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina) - Observing run: GS-2012B-Q-60.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998CMaPh.190..491B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998CMaPh.190..491B"><span>On the <span class="hlt">Distribution</span> of Free Path Lengthsfor the Periodic Lorentz <span class="hlt">Gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourgain, Jean; Golse, François; Wennberg, Bernt</p> <p></p> <p>Consider the domain<FORMULA FORM="DISPLAY" DISC="MATH"> and let the free path length be defined as<FORMULA FORM="DISPLAY" DISC="MATH"> The <span class="hlt">distribution</span> of values of is studied in the limit as for all . It is shown that the value is critical for this problem: in other words, the limiting behavior of depends only on whether γ is larger or smaller than .</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23003940','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23003940"><span>Instability in the dense supernova neutrino <span class="hlt">gas</span> with flavor-dependent angular <span class="hlt">distributions</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mirizzi, Alessandro; Serpico, Pasquale Dario</p> <p>2012-06-08</p> <p>The usual description of self-induced flavor conversions for neutrinos (ν's) in supernovae is based on the simplified assumption that all the ν's of the different species are emitted "half-isotropically" by a common neutrinosphere, in analogy to a blackbody emission. However, realistic supernova simulations show that ν angular <span class="hlt">distributions</span> at decoupling are far from being half-isotropic and, above all, are flavor dependent. We show that flavor-dependent angular <span class="hlt">distributions</span> may lead to crossing points in the angular spectra of different ν species (where F(ν(e))=F(ν(x)) and F(ν(e))=F(ν(x))) around which a new multiangle instability can develop. To characterize this effect, we carry out a linearized flavor stability analysis for different supernova neutrino angular <span class="hlt">distributions</span>. We find that this instability can shift the onset of the flavor conversions toward low radii and produce a smearing of the splitting features found with trivial ν emission models. As a result the spectral differences among ν's of different flavors could be strongly reduced.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995CSR....15..475W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995CSR....15..475W"><span>Abundance, <span class="hlt">distribution</span> and population structure of the copepod Calanus finmarchicus in a springtime right whale feeding area in the southwestern Gulf of <span class="hlt">Maine</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wishner, Karen F.; Schoenherr, Jill R.; Beardsley, Robert; Chen, Changsheng</p> <p></p> <p>Springtime aggregations of the planktivorous right whale ( Eubalaena glacialis) occur in the northern Great South Channel region of the southwestern Gulf of <span class="hlt">Maine</span>, where they feed upon dense concentrations of the copepod Calanus finmarchicus. This association was studied during the multidisciplinary South Channel Ocean Productivity Experiment (SCOPEX) in 1988 and 1989. The spatial and temporal variability of the abundance, geographic <span class="hlt">distribution</span>, and population structure of these copepods were analyzed using data from 99 vertically-stratified or horizontally-sequenced MOCNESS plankton tows. Higher water column abundances and higher relative proportion of older copepod lifestages occurred near feeding whales compared to sites without whales, but total water column copepod biomass and Calanus abundance did not always differ between these types of locations. This suggests that the whales seek out aggregations of older copepod lifestages rather than simply the most dense aggregations. Other factors (and perhaps an element of chance) may influence which specific patches, among all patches potentially suitable in terms of copepod abundance and age composition, the whales utilize at a particular time. The times and locations of the highest Calansus water column abundances varied between years, as did the presence of feeding whales, probably because of year-to-year differences in the springtime temperature cycle and current strength. A temporal progression of lifestages occurred within the region in both years during the roughly 3-week duration of each survey, indicative of a growing rather than a diapausing population, at least up to the copepodite 4 (C4) stage. Due in part to a delay in the springtime warming in 1989 compared to 1988, the copepod development cycle, which is largely driven by in situ temperature, was delayed about 1-2 weeks in 1989. Peak abundances of younger Calanus were found in the northwestern part of the region each year, whereas peak abundances of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22066260','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22066260"><span>Abnormal <span class="hlt">distribution</span> of microhardness in tungsten inert <span class="hlt">gas</span> arc butt-welded AZ61 magnesium alloy plates</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu Nan; Shen Jun; Xie Weidong; Wang Linzhi; Wang Dan; Min Dong</p> <p>2010-07-15</p> <p>In this study, the effects of heat input on the <span class="hlt">distribution</span> of microhardness of tungsten inert <span class="hlt">gas</span> (TIG) arc welded hot-extruded AZ61 magnesium alloy joints were investigated. The results show that with an increase of heat input, the <span class="hlt">distributions</span> of microhardness at the top and bottom of the welded joints are different because they are determined by both the effect of grain coarsening and the effect of dispersion strengthening. With an increase of the heat input, the microhardness of the heat-affected zone (HAZ) at the top and bottom of welded joints and the fusion zone (FZ) at the bottom of welded joints decreased gradually, while the microhardness of the FZ at the top of welded joints decreased initially and then increased sharply. The reason for the abnormal <span class="hlt">distribution</span> of microhardness of the FZ at the top of the welded joints is that this area is close to the heat source during welding and then large numbers of hard {beta}-Mg{sub 17}(Al,Zn){sub 12} particles are precipitated. Hence, in this case, the effect of dispersion strengthening dominated the microhardness.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003CMaPh.236..199C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003CMaPh.236..199C"><span>On the <span class="hlt">Distribution</span> of Free Path Lengths for the Periodic Lorentz <span class="hlt">Gas</span> III</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Caglioti, Emanuele; Golse, François</p> <p></p> <p>For r(0,1), let Zr={xR2|dist(x,Z2)>r/2} and define τr(x,v)=inf{t>0|x+tv∂Zr}. Let Φr(t) be the probability that τr(x,v)>=t for x and v uniformly <span class="hlt">distributed</span> in Zr and §1 respectively. We prove in this paper that <FORMULA FORM="DISPLAY" DISC="MATH"> as t-->+∞. This result improves upon the bounds on Φr in Bourgain-Golse-Wennberg [Commun. Math. Phys. 190, 491-508 (1998)]. We also discuss the applications of this result in the context of kinetic theory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2010-title49-vol3/pdf/CFR-2010-title49-vol3-sec192-197.pdf','CFR'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2010-title49-vol3/pdf/CFR-2010-title49-vol3-sec192-197.pdf"><span>49 CFR 192.197 - Control of the pressure of <span class="hlt">gas</span> delivered from high-pressure <span class="hlt">distribution</span> systems.</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2010&page.go=Go">Code of Federal Regulations, 2010 CFR</a></p> <p></p> <p>2010-10-01</p> <p>... designed to withstand abrasion of the <span class="hlt">gas</span>, impurities in <span class="hlt">gas</span>, cutting by the valve, and to resist permanent... connected and properly adjusted <span class="hlt">gas</span> utilization equipment. (6) A self-contained service regulator with...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20480029','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20480029"><span>Origin and <span class="hlt">distribution</span> of thiophenes and furans in <span class="hlt">gas</span> discharges from active volcanoes and geothermal systems.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando</p> <p>2010-03-31</p> <p>The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal <span class="hlt">gas</span> discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C(2)-C(20) species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C(4)H(8)O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2871125','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2871125"><span>Origin and <span class="hlt">Distribution</span> of Thiophenes and Furans in <span class="hlt">Gas</span> Discharges from Active Volcanoes and Geothermal Systems</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tassi, Franco; Montegrossi, Giordano; Capecchiacci, Francesco; Vaselli, Orlando</p> <p>2010-01-01</p> <p>The composition of non-methane organic volatile compounds (VOCs) determined in 139 thermal <span class="hlt">gas</span> discharges from 18 different geothermal and volcanic systems in Italy and Latin America, consists of C2–C20 species pertaining to the alkanes, alkenes, aromatics and O-, S- and N-bearing classes of compounds. Thiophenes and mono-aromatics, especially the methylated species, are strongly enriched in fluids emissions related to hydrothermal systems. Addition of hydrogen sulphide to dienes and electrophilic methylation involving halogenated radicals may be invoked for the formation of these species. On the contrary, the formation of furans, with the only exception of C4H8O, seems to be favoured at oxidizing conditions and relatively high temperatures, although mechanisms similar to those hypothesized for the production of thiophenes can be suggested. Such thermodynamic features are typical of fluid reservoirs feeding high-temperature thermal discharges of volcanoes characterised by strong degassing activity, which are likely affected by conspicuous contribution from a magmatic source. The composition of heteroaromatics in fluids naturally discharged from active volcanoes and geothermal areas can then be considered largely dependent on the interplay between hydrothermal vs. magmatic contributions. This implies that they can be used as useful geochemical tools to be successfully applied in both volcanic monitoring and geothermal prospection. PMID:20480029</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRD..11717202W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRD..11717202W"><span>Aerosol and <span class="hlt">gas</span> re-<span class="hlt">distribution</span> by shallow cumulus clouds: An investigation using airborne measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wonaschuetz, Anna; Sorooshian, Armin; Ervens, Barbara; Chuang, Patrick Y.; Feingold, Graham; Murphy, Shane M.; de Gouw, Joost; Warneke, Carsten; Jonsson, Haflidi H.</p> <p>2012-09-01</p> <p>Aircraft measurements during the 2006 Gulf of Mexico Atmospheric Composition and Climate Study (GoMACCS) are used to examine the influence of shallow cumulus clouds on vertical profiles of aerosol chemical composition, size <span class="hlt">distributions</span>, and secondary aerosol precursor gases. The data show signatures of convective transport of particles, gases and moisture from near the surface to higher altitudes, and of aqueous-phase production of aerosol mass (sulfate and organics) in cloud droplets and aerosol water. In cloudy conditions, the average aerosol volume concentration at an altitude of 2850 m, above typical cloud top levels, was found to be 34% of that at 450 m; for clear conditions, the same ratio was 13%. Both organic and sulfate mass fractions were on average constant with altitude (around 50%); however, the ratio of oxalate to organic mass increased with altitude (from 1% at 450 m to almost 9% at 3450 m), indicative of the influence of in-cloud production on the vertical abundance and characteristics of secondary organic aerosol (SOA) mass. A new metric termed "residual cloud fraction" is introduced as a way of quantifying the "cloud processing history" of an air parcel. Results of a parcel model simulating aqueous phase production of sulfate and organics reproduce observed trends and point at a potentially important role of SOA production, especially oligomers, in deliquesced aerosols. The observations emphasize the importance of shallow cumulus clouds in altering the vertical <span class="hlt">distribution</span> of aerosol properties that influence both their direct and indirect effect on climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70047811','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70047811"><span>Leaf <span class="hlt">gas</span> exchange and nutrient use efficiency help explain the <span class="hlt">distribution</span> of two Neotropical mangroves under contrasting flooding and salinity</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Cardona-Olarte, Pablo; Krauss, Ken W.; Twilley, Robert R.</p> <p>2013-01-01</p> <p>Rhizophora mangle and Laguncularia racemosa co-occur along many intertidal floodplains in the Neotropics. Their patterns of dominance shift along various gradients, coincident with salinity, soil fertility, and tidal flooding. We used leaf <span class="hlt">gas</span> exchange metrics to investigate the strategies of these two species in mixed culture to simulate competition under different salinity concentrations and hydroperiods. Semidiurnal tidal and permanent flooding hydroperiods at two constant salinity regimes (10 g L−1 and 40 g L−1) were simulated over 10 months. Assimilation (A), stomatal conductance (gw), intercellular CO2 concentration (Ci), instantaneous photosynthetic water use efficiency (PWUE), and photosynthetic nitrogen use efficiency (PNUE) were determined at the leaf level for both species over two time periods. Rhizophora mangle had significantly higher PWUE than did L. racemosa seedlings at low salinities; however, L. racemosa had higher PNUE and stomatal conductance and gw, accordingly, had greater intercellular CO2 (calculated) during measurements. Both species maintained similar capacities for assimilation at 10 and 40 g L−1 salinity and during both permanent and tidal hydroperiod treatments. Hydroperiod alone had no detectable effect on leaf <span class="hlt">gas</span> exchange. However, PWUE increased and PNUE decreased for both species at 40 g L−1 salinity compared to 10 g L−1. At 40 g L−1 salinity, PNUE was higher for L. racemosa than R. mangle with tidal flooding. These treatments indicated that salinity influences <span class="hlt">gas</span> exchange efficiency, might affect how gases are apportioned intercellularly, and accentuates different strategies for <span class="hlt">distributing</span> leaf nitrogen to photosynthesis for these two species while growing competitively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23879082','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23879082"><span>Possible health effects of liquefied petroleum <span class="hlt">gas</span> on workers at filling and <span class="hlt">distribution</span> stations of Gaza governorates.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sirdah, M M; Al Laham, N A; El Madhoun, R A</p> <p>2013-03-01</p> <p>Liquefied petroleum <span class="hlt">gas</span> (LPG) is widely used in the Gaza Strip for domestic purposes, in agriculture and industry and, illegally, in cars. This study aimed to identify possible health effects on workers exposed to LPG in Gaza governorates. Data were collected by a questionnaire interview, and haematological and biochemical analyses of venous blood samples were made from 30 workers at filling and <span class="hlt">distribution</span> stations and 30 apparently healthy controls. Statistically significant differences were found in all self-reported health-related complaints among LPG workers versus controls. LPG workers had significantly higher values of red blood cell counts, haemoglobin, haematocrit mean corpuscular haemoglobin and platelet counts. They also had significantly higher values of kidney function tests (urea, creatinine and uric acid) and liver function enzyme activities (aspartate aminotransferase and alanine aminotransferase). LPG workers at Gaza Strip petroleum stations are at higher risk for health-related symptoms and clinical abnormalities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EAS....71..175N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EAS....71..175N"><span>Yet Another Spectro-Interferometric Study of The <span class="hlt">Gas</span> <span class="hlt">Distribution</span> in The Enigmatic Semi-Detached Binary β Lyrae</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nemravová, J.; Mourard, D.; Harmanec, P.; Meilland, A.</p> <p>2015-12-01</p> <p>The majority of close binaries undergo episodes of mass transfer between their components, which completely change their further evolution. Simulations and observations agree that the mass transfer has two phases: i) short and rapid one, and ii) long and slow one. The bulk of the mass is likely exchanged during the rapid phase, but due to its shortness, systems undergoing this phase are rare, but they hold the key to understanding of the process. One system that is either undergoing the rapid mass transfer phase or is in a transient phase between the two phases is β Lyrae. Our goal is to map the <span class="hlt">distribution</span> of circumstellar <span class="hlt">gas</span> in the system. To achieve it, a series of spectro-interferometric observations acquired with the optical instrument VEGA/CHARA are investigated. Here we present our tools and preliminary results of our analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AtmEn..44.5022L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AtmEn..44.5022L"><span>Polycyclic aromatic hydrocarbons in air on small spatial and temporal scales - II. Mass size <span class="hlt">distributions</span> and <span class="hlt">gas</span>-particle partitioning</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lammel, Gerhard; Klánová, Jana; Ilić, Predrag; Kohoutek, Jiří; Gasić, Bojan; Kovacić, Igor; Škrdlíková, Lenka</p> <p>2010-12-01</p> <p>Polycyclic aromatic hydrocarbons (PAHs) were measured together with inorganic air pollutants at two urban sites and one rural background site in the Banja Luka area, Bosnia and Hercegovina, during 72 h in July 2008 using a high time resolution (5 samples per day) with the aim to study <span class="hlt">gas</span>-particle partitioning, aerosol mass size <span class="hlt">distributions</span> and to explore the potential of a higher time resolution (4 h-sampling). In the particulate phase the mass median diameters of the PAHs were found almost exclusively in the accumulation mode (0.1-1.0 μm of size). These were larger for semivolatile PAHs than for non-volatile PAHs. <span class="hlt">Gas</span>-particle partitioning of semivolatile PAHs was strongly influenced by temperature. The results suggest that the Junge-Pankow model is inadequate to explain the inter-species variation and another process must be significant for phase partitioning which is less temperature sensitive than adsorption. Care should be taken when interpreting slopes m of plots of the type log K p = m log p L0 + b based on 24 h means, as these are found sensitive to the time averaging, i.e. tend to be higher than when based on 12 h-mean samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27553493','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27553493"><span>Charge state <span class="hlt">distribution</span> studies of pure and oxygen mixed krypton ECR plasma - signature of isotope anomaly and <span class="hlt">gas</span> mixing effect.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kumar, Pravin; Mal, Kedar; Rodrigues, G</p> <p>2016-11-01</p> <p>We report the charge state <span class="hlt">distributions</span> of the pure, 25% and 50% oxygen mixed krypton plasma to shed more light on the understanding of the <span class="hlt">gas</span> mixing and the isotope anomaly [A. G. Drentje, Rev. Sci. Instrum. 63 (1992) 2875 and Y Kawai, D Meyer, A Nadzeyka, U Wolters and K Wiesemann, Plasma Sources Sci. Technol. 10 (2001) 451] in the electron cyclotron resonance (ECR) plasmas. The krypton plasma was produced using a 10 GHz all-permanent-magnet ECR ion source. The intensities of the highly abundant four isotopes, viz. (82) Kr (~11.58%), (83) Kr (~11.49%), (84) Kr (~57%) and (86) Kr (17.3%) up to ~ +14 charge state have been measured by extracting the ions from the plasma and analysing them in the mass and the energy using a large acceptance analyzer-cum-switching dipole magnet. The influence of the oxygen <span class="hlt">gas</span> mixing on the isotopic krypton ion intensities is clearly evidenced beyond +9 charge state. With and without oxygen mixing, the charge state <span class="hlt">distribution</span> of the krypton ECR plasma shows the isotope anomaly with unusual trends. The anomaly in the intensities of the isotopes having quite closer natural abundance, viz. (82) Kr, (86) Kr and (83) Kr, (86) Kr is prominent, whereas the intensity ratio of (86) Kr to (84) Kr shows a weak signature of it. The isotope anomaly tends to disappear with increasing oxygen mixing in the plasma. The observed trends in the intensities of the krypton isotopes do not follow the prediction of linear Landau wave damping in the plasma. Copyright © 2016 John Wiley & Sons, Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8317E..1CH','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8317E..1CH"><span>Two and three-dimensional segmentation of hyperpolarized 3He magnetic resonance imaging of pulmonary <span class="hlt">gas</span> <span class="hlt">distribution</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heydarian, Mohammadreza; Kirby, Miranda; Wheatley, Andrew; Fenster, Aaron; Parraga, Grace</p> <p>2012-03-01</p> <p>A semi-automated method for generating hyperpolarized helium-3 (3He) measurements of individual slice (2D) or whole lung (3D) <span class="hlt">gas</span> <span class="hlt">distribution</span> was developed. 3He MRI functional images were segmented using two-dimensional (2D) and three-dimensional (3D) hierarchical K-means clustering of the 3He MRI signal and in addition a seeded region-growing algorithm was employed for segmentation of the 1H MRI thoracic cavity volume. 3He MRI pulmonary function measurements were generated following two-dimensional landmark-based non-rigid registration of the 3He and 1H pulmonary images. We applied this method to MRI of healthy subjects and subjects with chronic obstructive lung disease (COPD). The results of hierarchical K-means 2D and 3D segmentation were compared to an expert observer's manual segmentation results using linear regression, Pearson correlations and the Dice similarity coefficient. 2D hierarchical K-means segmentation of ventilation volume (VV) and ventilation defect volume (VDV) was strongly and significantly correlated with manual measurements (VV: r=0.98, p<.0001 VDV: r=0.97, p<.0001) and mean Dice coefficients were greater than 92% for all subjects. 3D hierarchical K-means segmentation of VV and VDV was also strongly and significantly correlated with manual measurements (VV: r=0.98, p<.0001 VDV: r=0.64, p<.0001) and the mean Dice coefficients were greater than 91% for all subjects. Both 2D and 3D semi-automated segmentation of 3He MRI <span class="hlt">gas</span> <span class="hlt">distribution</span> provides a way to generate novel pulmonary function measurements.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/7069660','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/7069660"><span>Vapor <span class="hlt">distribution</span> of trichloroethene and related compounds in soil <span class="hlt">gas</span> above contaminated ground water at Picatinny Arsenal, New Jersey</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smith, J.A. )</p> <p>1988-09-01</p> <p>From 1960 to 1981, wastewater from metal-plating operations was discharged into two unlined filtration pits adjacent to Building 24 at Picatinny Arsenal in Morris County, New Jersey. As a result, the unconfined, sand and gravel aquifer that underlies the site has been contaminated with several chlorinated organic compounds. The major component of the organic contamination is trichloroethene (TCE), although cis-1,2-dichloroethene (DCE) and tetrachloroethene (PCE) also have been identified in some water samples. Details of the ground-water contamination have been reported elsewhere. The goals of this study are to quantify the concentration of purgeable organic compounds in the soil <span class="hlt">gas</span> above the <span class="hlt">main</span> axis of the contaminant plume, and to investigate the effect of soil moisture content on the sorption of TCE vapor to soil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1786g0002K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1786g0002K"><span>Influence of state-to-state vibrational <span class="hlt">distributions</span> on transport coefficients of a single <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kustova, Elena V.; Kremer, Gilberto M.</p> <p>2016-11-01</p> <p>In this work the influence of the size of vibrationally and rotationally excited molecules on the collision integrals required for the calculation of state-to-state transport coefficients is discussed. Several diatomic molecules are considered: N2, O2, NO, H2, Cl2. It is shown that whereas the molecular size is not affected by rotational excitation, it strongly depends on the vibrational state. Particular emphasis is given to the shear viscosity and thermal conductivity coefficients calculated in the temperature range 2 500-20 000 K for equilibrium Boltzmann vibrational <span class="hlt">distributions</span>. It is shown that under conditions of local thermal equilibrium, the effect of vibrational excitation on the shear viscosity and thermal conductivity coefficients are found to be negligible for temperatures below 5 000 K, except for the case of Cl2 molecule where at 5 000 K the effect is about 10%. For T > 10 000 K, the contribution of excited states becomes important and reaches 10-25%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19780033217&hterms=distribution+product&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddistribution%2Bproduct','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19780033217&hterms=distribution+product&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Ddistribution%2Bproduct"><span>Product <span class="hlt">distributions</span> for some thermal energy charge transfer reactions of rare <span class="hlt">gas</span> ions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anicich, V. G.; Laudenslager, J. B.; Huntress, W. T., Jr.; Futrell, J. H.</p> <p>1977-01-01</p> <p>Ion cyclotron resonance methods were used to measure the product <span class="hlt">distributions</span> for thermal-energy charge-transfer reactions of He(+), Ne(+), and Ar(+) ions with N2, O2, CO, NO, CO2, and N2O. Except for the He(+)-N2 reaction, no molecular ions were formed by thermal-energy charge transfer from He(+) and Ne(+) with these target molecules. The propensity for dissociative ionization channels in these highly exothermic charge-transfer reactions at thermal energies contrasts with the propensity for formation of parent molecular ions observed in photoionization experiments and in high-energy charge-transfer processes. This difference is explained in terms of more stringent requirements for energy resonance and favorable Franck-Condon factors at thermal ion velocities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1076999','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1076999"><span>Dual Layer Monolith ATR of Pyrolysis Oil for <span class="hlt">Distributed</span> Synthesis <span class="hlt">Gas</span> Production</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lawal, Adeniyi</p> <p>2012-09-29</p> <p>We have successfully demonstrated a novel reactor technology, based on BASF dual layer monolith catalyst, for miniaturizing the autothermal reforming of pyrolysis oil to syngas, the second and most critical of the three steps for thermochemically converting biomass waste to liquid transportation fuel. The technology was applied to aged as well as fresh samples of pyrolysis oil derived from five different biomass feedstocks, namely switch-grass, sawdust, hardwood/softwood, golden rod and maple. Optimization of process conditions in conjunction with innovative reactor system design enabled the minimization of carbon deposit and control of the H2/CO ratio of the product <span class="hlt">gas</span>. A comprehensive techno-economic analysis of the integrated process using in part, experimental data from the project, indicates (1) net energy recovery of 49% accounting for all losses and external energy input, (2) weight of diesel oil produced as a percent of the biomass to be ~14%, and (3) for a demonstration size biomass to Fischer-Tropsch liquid plant of ~ 2000 daily barrels of diesel, the price of the diesel produced is ~$3.30 per gallon, ex. tax. However, the extension of catalyst life is critical to the realization of the projected economics. Catalyst deactivation was observed and the modes of deactivation, both reversible and irreversible were identified. An effective catalyst regeneration strategy was successfully demonstrated for reversible catalyst deactivation while a catalyst preservation strategy was proposed for preventing irreversible catalyst deactivation. Future work should therefore be focused on extending the catalyst life, and a successful demonstration of an extended (> 500 on-stream hours) catalyst life would affirm the commercial viability of the process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...575A..37M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...575A..37M"><span>Abundance and temperature <span class="hlt">distributions</span> in the hot intra-cluster <span class="hlt">gas</span> of Abell 4059</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mernier, F.; de Plaa, J.; Lovisari, L.; Pinto, C.; Zhang, Y.-Y.; Kaastra, J. S.; Werner, N.; Simionescu, A.</p> <p>2015-03-01</p> <p>Using the EPIC and RGS data from a deep (200 ks) XMM-Newton observation, we investigate the temperature structure (kT and σT) and the abundances of nine elements (O, Ne, Mg, Si, S, Ar, Ca, Fe, and Ni) of the intra-cluster medium (ICM) in the nearby (z = 0.046) cool-core galaxy cluster Abell 4059. Next to a deep analysis of the cluster core, a careful modelling of the EPIC background allows us to build radial profiles up to 12' (~650 kpc) from the core. Probably because of projection effects, the temperature ICM is not found to be in single phase, even in the outer parts of the cluster. The abundances of Ne, Si, S, Ar, Ca, and Fe, but also O are peaked towards the core. The elements Fe and O are still significantly detected in the outermost annuli, which suggests that the enrichment by both type Ia and core-collapse SNe started in the early stages of the cluster formation. However, the particularly high Ca/Fe ratio that we find in the core is not well reproduced by the standard SNe yield models. Finally, 2D maps of temperature and Fe abundance are presented and confirm the existence of a denser, colder, and Fe-rich ridge south-west of the core, previously observed by Chandra. The origin of this asymmetry in the hot <span class="hlt">gas</span> of the cluster core is still unclear, but it might be explained by a past intense ram-pressure stripping event near the central cD galaxy. Appendices are available in electronic form at http://www.aanda.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/22348521','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/22348521"><span>Subarcsecond observations of NGC 7538 IRS 1: Continuum <span class="hlt">distribution</span> and dynamics of molecular <span class="hlt">gas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhu, Lei; Shi, Hui; Zhao, Jun-Hui; Wright, M. C. H.; Sandell, Göran; Wu, Yue-Fang; Brogan, Crystal; Corder, Stuartt</p> <p>2013-12-10</p> <p>We report new results based on the analysis of the Submillimeter Array (SMA) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) observations of NGC 7538 IRS 1 at 1.3 and 3.4 mm with subarcsecond resolutions. With angular resolutions ∼0.''7, the SMA and CARMA observations show that the continuum emission at 1.3 and 3.4 mm from the hyper-compact H II region IRS 1 is dominated by a compact source with a tail-like extended structure to the southwest of IRS 1. With a CARMA B-array image at 1.3 mm convolved to 0.''1, we resolve the hyper-compact H II region into two components: an unresolved hyper-compact core, and a north-south extension with linear sizes of <270 AU and ∼2000 AU, respectively. The fine structure observed with CARMA is in good agreement with the previous Very Large Array results at centimeter wavelengths, suggesting that the hyper-compact H II region at the center of IRS 1 is associated with an ionized bipolar outflow. We image the molecular lines OCS(19-18) and CH{sub 3}CN(12-11) as well as {sup 13}CO(2-1) surrounding IRS 1, showing a velocity gradient along the southwest-northeast direction. The spectral line profiles in {sup 13}CO(2-1), CO(2-1), and HCN(1-0) observed toward IRS 1 show broad redshifted absorption, providing evidence for <span class="hlt">gas</span> infall with rates in the range of 3-10 × 10{sup –3} M {sub ☉} yr{sup –1} inferred from our observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16956243','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16956243"><span>Reactions of methyl fluoride with atomic transition-metal and <span class="hlt">main</span>-group cations: <span class="hlt">gas</span>-phase room-temperature kinetics and periodicities in reactivity.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Xiang; Koyanagi, Gregory K; Bohme, Diethard K</p> <p>2006-09-14</p> <p>Reactions of CH(3)F have been surveyed systematically at room temperature with 46 different atomic cations using an inductively coupled plasma/selected-ion flow tube tandem mass spectrometer. Rate coefficients and product <span class="hlt">distributions</span> were measured for the reactions of fourth-period atomic ions from K(+) to Se(+), of fifth-period atomic ions from Rb(+) to Te(+) (excluding Tc(+)), and of sixth-period atomic ions from Cs(+) to Bi(+). Primary reaction channels were observed corresponding to F atom transfer, CH(3)F addition, HF elimination, and H(2) elimination. The early-transition-metal cations exhibit a much more active chemistry than the late-transition-metal cations, and there are periodic features in the chemical activity and reaction efficiency that maximize with Ti(+), As(+), Y(+), Hf(+), and Pt(+). F atom transfer appears to be thermodynamically controlled, although a periodic variation in efficiency is observed within the early-transition-metal cations which maximizes with Ti(+), Y(+), and Hf(+). Addition of CH(3)F was observed exclusively (>99%) with the late-fourth-period cations from Mn(+) to Ga(+), the fifth-period cations from Ru(+) to Te(+), and the sixth-period cations from Hg(+) to Bi(+) as well as Re(+). Periodic trends are observed in the effective bimolecular rate coefficient for CH(3)F addition, and these are consistent with expected trends in the electrostatic binding energies of the adduct ions and measured trends in the standard free energy of addition. HF elimination is the major reaction channel with As(+), while dehydrogenation dominates the reactions of W(+), Os(+), Ir(+), and Pt(+). Sequential F atom transfer is observed with the early-transition-metal cations, with the number of F atoms transferred increasing across the periodic table from two to four, maximizing at four for the group 5 cations Nb(+)(d(4)) and Ta(+)(d(3)s(1)), and stopping at two with V(+)(d(4)). Sequential CH(3)F addition was observed with many atomic cations and all of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/460195','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/460195"><span>ZTEK`s ultra-high efficiency fuel cell/<span class="hlt">gas</span> turbine system for <span class="hlt">distributed</span> generation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hsu, M.; Nathanson, D.; Bradshaw, D.T.</p> <p>1996-12-31</p> <p>Ztek`s Planar Solid Oxide Fuel Cell (SOFC) system has exceptional potential for utility electric power generation because of: simplicity of components construction, capability for low cost manufacturing, efficient recovery of very high quality by-product heat (up to 1000{degrees}C), and system integration simplicity. Utility applications of the Solid Oxide Fuel Cell are varied and include <span class="hlt">distributed</span> generation units (sub-MW to 30MW capacity), repowering existing power plants (i.e. 30MW to 100MW), and multi-megawatt central power plants. A TVA/EPRI collaboration program involved functional testing of the advanced solid oxide fuel cell stacks and design scale-up for <span class="hlt">distributed</span> power generation applications. The emphasis is on the engineering design of the utility modules which will be the building blocks for up to megawatt scale power plants. The program has two distinctive subprograms: Verification test on a 1 kW stack and 25kW module for utility demonstration. A 1 kW Planar SOFC stack was successfully operated for 15,000 hours as of December, 1995. Ztek began work on a 25kW SOFC Power System for TVA, which plans to install the 25kW SOFC at a host site for demonstration in 1997. The 25kW module is Ztek`s intended building block for the commercial use of the Planar SOFC. Systems of up to megawatt capacity can be obtained by packaging the modules in 2-dimensional or 3-dimensional arrays.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.A51N0280W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.A51N0280W"><span>A Comprehensive Archive of Aerosol and Trace <span class="hlt">Gas</span> Spatial <span class="hlt">Distributions</span> for Model and Satellite Validation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, J. C.; Meland, B. S.; Axisa, D.</p> <p>2015-12-01</p> <p>The University of Denver Aerosol Group has assembled measured aerosol size <span class="hlt">distributions</span>, gaseous concentrations, and atmospheric state variables covering a 30 year time period into one comprehensive archive. Measurements were made during the period 1987-2013 and include data from a total of 21 NASA field campaigns. Measurements were taken from the ground to over 21 km in altitude, from 72 S Latitude to 90 N latitude on over 300 individual flights on NASA Research Aircraft. Aerosol measurements were made with the University of Denver's Nucleation-Mode Aerosol Size Spectrometer (NMASS), Focused Cavity Aerosol Spectrometer, and/or a low-pressure Condensation Particle Counter (CPC) depending on the specific campaign. The science payloads varied with the campaign objectives, but the aerosol data were invariably acquired in conjunction with measurements by other investigators placing them in the context of atmospheric composition. The archive includes location and time of the measurements along with the tropopause heights and selected atmospheric composition and state data such as ambient temperatures and pressures, abundances of ozone, N2O, oxides of nitrogen, water vapor, CO2 etc. The data archive is stored in NetCDF format and includes all relevant metadata for measured quantities. This archive will be hosted by NASA and will be available to the public for model validation. The data includes indexing by scientific campaign, date, and spatial coordinates. This will facilitate comparisons across the available range of times, locations and related measurements. This data set has been used for validation of satellite remote sensing data. Coincident measurements of aerosol size <span class="hlt">distributions</span> were used to calculate extinction profiles which were compared to those retrieved with the SAGE II satellite. Agreement between extinctions derived from the in situ size measurements and those provided by SAGE II was good for the 452, 525, and 1020 nm wavelength channels, but poor for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017OptEn..56a6106Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017OptEn..56a6106Q"><span>Locking <span class="hlt">distributed</span> feedback laser diode frequency to <span class="hlt">gas</span> absorption lines based on genetic programming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quan, Wei; Li, Guanghui; Fang, Zishan; Zhai, Yueyang; Li, Xinyi; Liu, Feng</p> <p>2017-01-01</p> <p><span class="hlt">Distributed</span> feedback laser is widely used as the pump beam and probe beam in atomic physical and quantum experiments. As the frequency stability is a vital characteristic to the laser diode in these experiments, a saturated absorption frequency stabilization method assisted with the function of current and frequency is proposed. The relationship between the current and frequency is acquired based on the genetic programming (GP) algorithm. To verify the feasibility of the method, the frequency stabilization system is comprised of two parts that are modeling the relation between the current and frequency by GP and processing the saturated absorption signal. The results of the frequency stabilization experiment proved that this method can not only narrow the frequency searching range near the atomic line center but also compensate for the phase delay between the saturated absorption peak and the zero crossing point of the differential error signal. The reduced phase delay increases the locking probability and makes the wavelength drift only 0.015 pm/h, which converted to frequency drift is 7 MHz/h after frequency locking on the Rb absorption line.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/949736','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/949736"><span>Neutron Scattering Measurements of Hydrogen <span class="hlt">Distribution</span> in a Zircaloy-4 Alloy Charged with Hydrogen <span class="hlt">Gas</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Garlea, Elena; Garlea, Vasile O; Choo, Hahn; Hubbard, Camden R; Liaw, Peter K; Rack, P. D.</p> <p>2007-01-01</p> <p>Neutron incoherent scattering measurements were conducted on Zircaloy-4 round bars. The specimens were charged in a tube furnace at 430 C, using a 12.5 vol. % hydrogen in an argon mixture for 30, 60, and 90 minutes at 13.8 kPa pressure. The volume-average neutron diffraction measurements showed the presence of the face-centered-cubic delta zirconium hydride ({delta}-ZrH{sub 2}) phase in the hydrogenated specimens. The assessment of the background in the diffraction profiles due to the incoherent scattering from the hydrogen atoms was carried out by performing inelastic scans around zero energy transfer and at a fixed two-theta value for which there was only flat background and no coherent scattering. To estimate the relative amount of hydrogen in the Zircaloy-4 samples, the increase in incoherent scattering intensities with hydrogen content was calibrated using samples for which the hydrogen content was known. Measurement of the background scattering from locations within the round bar was also performed to map the <span class="hlt">distribution</span> of hydrogen content.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1116988','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1116988"><span>Electrical Resistivity Investigation of <span class="hlt">Gas</span> Hydrate <span class="hlt">Distribution</span> in Mississippi Canyon Block 118, Gulf of Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dunbar, John</p> <p>2012-12-31</p> <p>Electrical methods offer a geophysical approach for determining the sub-bottom <span class="hlt">distribution</span> of hydrate in deep marine environments. Methane hydrate is essentially non-conductive. Hence, sediments containing hydrate are more resistive than sediments without hydrates. To date, the controlled source electromagnetic (CSEM) method has been used in marine hydrates studies. This project evaluated an alternative electrical method, direct current resistivity (DCR), for detecting marine hydrates. DCR involves the injection of direct current between two source electrodes and the simultaneous measurement of the electric potential (voltage) between multiple receiver electrodes. The DCR method provides subsurface information comparable to that produced by the CSEM method, but with less sophisticated instrumentation. Because the receivers are simple electrodes, large numbers can be deployed to achieve higher spatial resolution. In this project a prototype seafloor DCR system was developed and used to conduct a reconnaissance survey at a site of known hydrate occurrence in Mississippi Canyon Block 118. The resulting images of sub-bottom resistivities indicate that high-concentration hydrates at the site occur only in the upper 50 m, where deep-seated faults intersect the seafloor. Overall, there was evidence for much less hydrate at the site than previously thought based on available seismic and CSEM data alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AMT.....7..713F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AMT.....7..713F"><span>Near-infrared remote sensing of Los Angeles trace <span class="hlt">gas</span> <span class="hlt">distributions</span> from a mountaintop site</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, D.; Pongetti, T. J.; Blavier, J.-F. L.; Crawford, T. J.; Manatt, K. S.; Toon, G. C.; Wong, K. W.; Sander, S. P.</p> <p>2014-03-01</p> <p>The Los Angeles basin is a significant anthropogenic source of major greenhouse gases (CO2 and CH4) and the pollutant CO, contributing significantly to regional and global climate change. We present a novel approach for monitoring the spatial and temporal <span class="hlt">distributions</span> of greenhouse gases in the Los Angeles basin using a high-resolution spectroscopic remote sensing technique. A new Fourier transform spectrometer called CLARS-FTS has been deployed since May, 2010, at Jet Propulsion Laboratory (JPL)'s California Laboratory for Atmospheric Remote Sensing (CLARS) on Mt. Wilson, California, for automated long-term measurements of greenhouse gases. The instrument design and performance of CLARS-FTS are presented. From its mountaintop location at an altitude of 1673 m, the instrument points at a programmed sequence of ground target locations in the Los Angeles basin, recording spectra of reflected near-IR solar radiation. Column-averaged dry-air mole fractions of greenhouse gases (XGHG) including XCO2, XCH4, and XCO are retrieved several times per day for each target. Spectra from a local Spectralon scattering plate are also recorded to determine background (free tropospheric) column abundances above the site. Comparisons between measurements from LA basin targets and the Spectralon plate provide estimates of the boundary layer partial column abundances of the measured species. Algorithms are described for transforming the measured interferograms into spectra, and for deriving column abundances from the spectra along with estimates of the measurement precision and accuracy. The CLARS GHG measurements provide a means to infer relative, and possibly absolute, GHG emissions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27815028','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27815028"><span>Application of portable <span class="hlt">gas</span> detector in point and scanning method to estimate spatial <span class="hlt">distribution</span> of methane emission in landfill.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lando, Asiyanthi Tabran; Nakayama, Hirofumi; Shimaoka, Takayuki</p> <p>2017-01-01</p> <p>Methane from landfills contributes to global warming and can pose an explosion hazard. To minimize these effects emissions must be monitored. This study proposed application of portable <span class="hlt">gas</span> detector (PGD) in point and scanning measurements to estimate spatial <span class="hlt">distribution</span> of methane emissions in landfills. The aims of this study were to discover the advantages and disadvantages of point and scanning methods in measuring methane concentrations, discover spatial <span class="hlt">distribution</span> of methane emissions, cognize the correlation between ambient methane concentration and methane flux, and estimate methane flux and emissions in landfills. This study was carried out in Tamangapa landfill, Makassar city-Indonesia. Measurement areas were divided into basic and expanded area. In the point method, PGD was held one meter above the landfill surface, whereas scanning method used a PGD with a data logger mounted on a wire drawn between two poles. Point method was efficient in time, only needed one person and eight minutes in measuring 400m(2) areas, whereas scanning method could capture a lot of hot spots location and needed 20min. The results from basic area showed that ambient methane concentration and flux had a significant (p<0.01) positive correlation with R(2)=0.7109 and y=0.1544 x. This correlation equation was used to describe spatial <span class="hlt">distribution</span> of methane emissions in the expanded area by using Kriging method. The average of estimated flux from scanning method was 71.2gm(-2)d(-1) higher than 38.3gm(-2)d(-1) from point method. Further, scanning method could capture the lower and higher value, which could be useful to evaluate and estimate the possible effects of the uncontrolled emissions in landfill.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DPS....4851009G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DPS....4851009G"><span>Size and Perihelion <span class="hlt">Distribution</span> of S and Q-type Asteroid Spectral Slopes from the Near Earth Region Through the <span class="hlt">Main</span> Belt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Graves, Kevin; Minton, David A.; Hirabayashi, Masatoshi; Carry, Benoit; DeMeo, Francesca E.</p> <p>2016-10-01</p> <p>High resolution spectral observations of small S-type and Q-type Near Earth Asteroids (NEAs) have shown two important trends. The spectral slope of these asteroids, which is a good indication of the amount of space weathering the surface has received, has been shown to decrease with decreasing perihelion and size. Specifically, these trends show that there are less weathered surfaces at low perihelion and small sizes. With recent results from all-sky surveys such as the Sloan Digital Sky Survey's (SDSS) Moving Object Catalog, we have gained an additional data set to test the presence of these trends in the NEAs as well as the Mars Crossers (MCs) and the <span class="hlt">Main</span> Belt. We use an analog to the spectral slope in the SDSS data which is the slope through the g', r' and i' filters, known as the gri-slope, to investigate the amount of weathering that is present among small asteroids throughout the inner solar system. We find that the trend of the gri-slope decreases with decreasing size at nearly the same rate in the <span class="hlt">Main</span> Belt as in the MC and NEA regions. We propose that these results suggest a ubiquitous presence of Q-types and S-types with low spectral slopes at small sizes throughout the inner solar system, from the <span class="hlt">Main</span> Belt to the NEA region. Additionally, we suggest that the trend of decreasing spectral slope with perihelion may only be valid at perihelia of approximately less than 1 AU. These results suggest a change in the interpretation for the formation of Q-type asteroids. Planetary encounters may help to explain the high fraction of Q-types at low perihelia, but another process which is present everywhere must also be refreshing the surfaces of these asteroids. We suggest the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect as a possible mechanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20708191','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20708191"><span>Analysis of polysulfides in drinking water <span class="hlt">distribution</span> systems using headspace solid-phase microextraction and <span class="hlt">gas</span> chromatography-mass spectrometry.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kristiana, Ina; Heitz, Anna; Joll, Cynthia; Sathasivan, Arumugam</p> <p>2010-09-17</p> <p>Sulfide and polysulfides are strong nucleophiles and reducing agents that participate in many environmentally significant processes such as the formation of sulfide minerals and volatile organic sulfur compounds. Their presence in drinking water <span class="hlt">distribution</span> systems are of particular concern and need to be assessed, since these species consume disinfectants and dissolved oxygen, react with metal ions to produce insoluble metal sulfides, and cause taste and odour problems. The analysis of sulfide and polysulfides in drinking water <span class="hlt">distribution</span> systems