Science.gov

Sample records for active gas venting

  1. An analysis of flaring and venting activity in the Alberta upstream oil and gas industry.

    PubMed

    Johnson, Matthew R; Coderre, Adam R

    2011-02-01

    Alberta, Canada, is an important global producer of petroleum resources. In association with this production, large amounts of gas (1.14 billion m3 in 2008) are flared or vented. Although the amount of flaring and venting has been measurably reduced since 2002, data from 2005 reveal sharp increases in venting, which have important implications in terms of resource conservation and greenhouse gas emissions (which exceeded 8 million tonnes of carbon dioxide equivalent in 2008). With use of extensive monthly production data for 18,203 active batteries spanning the years 2002-2008 obtained in close cooperation with the Alberta Energy Resources Conservation Board, a detailed analysis has been completed to examine activity patterns of flaring and venting and reasons behind these trends in the Alberta upstream oil and gas industry. In any given year, approximately 6000 batteries reported flaring and/or venting, but the distribution of volumes flared and vented at individual sites was highly skewed, such that small numbers of sites handled large fractions of the total gas flaring and venting in the Province. Examination of month-to-month volume variability at individual sites, cast in terms of a nominal turndown ratio that would be required for a compressor to capture that gas and direct it into a pipeline, further revealed that volumes at a majority of sites were reasonably stable and there was no evidence that larger or more stable sites had been preferentially reduced, leaving potential barriers to future mitigation. Through linking of geospatial data with production data coupled with additional statistical analysis, the 31.2% increase in venting volumes since 2005 was revealed to be predominantly associated with increased production of heavier oils and bitumen in the Lloydminster region of the Province. Overall, the data suggest that quite significant reductions in flaring and venting could be realized by seeking mitigation solutions for only the largest batteries in

  2. Active seafloor gas vents on the Shelf and upper Slope in Canadian Beaufort Sea

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S. R.; Hughes Clarke, J. E.; Blasco, S.; Taylor, A. E.; Melling, H.; Vagle, S.; Conway, K.; Riedel, M.; Lundsten, E.; Gwiazda, R.

    2012-12-01

    seafloor topographic features on the continental slope suggests these are also active vent sites. Vigorous degassing of methane and pore water freshening in cores from features suggest the presence of near seafloor gas hydrate accumulations. If correct, a feature at 290m depth hosts the shallowest known marine gas hydrate occurrence. Here a layer of very cold ocean waters (-1.7°C) extends to ~200m depths, below which the temperature increases slowly with depth. A consequence of the exceptionally low upper water column temperatures is that the top of the methane hydrate stability zone is only slightly shallower that the 290m seafloor feature. Thus, gas hydrate harbored within seafloor sediments at 290m is vulnerable to decomposition with even subtle climatically-induced warming of the overlying water. Further geoscience studies are planned for 2012 and 2013 to study geological processes, geohazards and the sensitivity of the shelf / slope setting to climate change in the Arctic.

  3. Violent Gas Venting on the Heng-Chun Mud Volcano, South China Sea Active Continental Margin offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, S.; Cheng, W. Y.; Tseng, Y. T.; Chen, N. C.; Hsieh, I. C.; Yang, T. F.

    2014-12-01

    Accumulation of methane as gas hydrate under the sea floor has been considered a major trap for both thermal and biogenic gas in marine environment. Aided by rapid AOM process near the sea floor, fraction of methane escaping the sea floor has been considered at minuscule. However, most studies focused mainly on deepwater gas hydrate systems where gas hydrate remain relatively stable. We have studied methane seeps on the active margin offshore Taiwan, where rapid tectonic activities occur. Our intention is to evaluate the scale and condition of gas seeps in the tectonic active region. Towcam, coring, heat probe, chirp, multibeam bathymetric mapping and echo sounding were conducted at the study areas. Our results showed that gas is violently venting at the active margin, not only through sediments, but also through overlying sea water, directly into the atmosphere. Similar ventings, but, not in this scale, have also been identified previously in the nearby region. High concentrations of methane as well as traces of propane were found in sediments and in waters with flares. In conjunction, abundant chemosynthetic community, life mussel, clams, tube worms, bacterial mats together with high concentrations of dissolve sulfide, large authigenic carbonate buildups were also found. Our results indicate that methane could be another major green house gas in the shallow water active margin region.

  4. Gas generation results and venting study for transuranic waste drums

    SciTech Connect

    Kazanjian, A.R.; Arnold, P.M.; Simmons, W.C.; D'Amico, E.L.

    1985-09-23

    Sixteen waste drums, containing six categories of plutonium-contaminated waste, were monitored for venting and gas generation for six months. The venting devices tested appeared adequate to relieve pressure and prevent hydrogen accumulation. Most of the gas generation, primarily H2 and CO2, was due to radiolytic decomposition of the hydrogenous wastes. Comparison of the gas yields with those obtained previously in laboratory tests showed very reasonable agreement with few exceptions.

  5. Mud volcano venting induced gas hydrate formation at the upper slope accretionary wedge, offshore SW Taiwan

    NASA Astrophysics Data System (ADS)

    Lin, Saulwood; Tseng, Yi-Ting; Cheng, Wan-Yen; Chou, Cheng-Tien; Chen, NeiChen; Hsieh, I.-Chih

    2016-04-01

    TsanYao Mud Volcano (TYMV) is the largest mud volcano cone in the Hengchun Mud Volcano Group (HCMVG), located at the upper slope of the accrretionary wedge, southwest of Taiwan. The region is under active tectonic activity with the Philippine Plate, moving northwestward at a rate of ~8 cm/year. This region also receives huge quantity of suspended particle load of ~100 mT/year at present time from adjacent small rivers of the Island of Taiwan. Large loads of suspended sediments influx become a major source of organic carbon and later gas and other hydrocarbon. Gas and fluid in the mud volcano are actively venting from deep to the sea floor on the upper slope of the accretionary wedge. In order to understand venting on the HCMVG, echo sounder, towcam and coring were carried out. Pore water sulfate, chloride, potassium, calcium, stable isotope O-18, gas compositions, dissolved sulfide were analysed. The HCMVG consists of 12 volcano cones of different sizes. Large quantity of gas and fluid are venting directly from deep to the TYMV structure high, as well as 50+ other vents as appeared as flares on the echo sounder. Some flares are reaching to the atmosphere and likely a source of green house gases to the atmosphere. Venting fluids include gas bubbles, suspended particle, mud, and breccia. Breccia size could reach more than 12 cm in diameter. Circular bands in different color appeared around the cone may represent stages of vent eruptions. Compositions of vent gas include methane, ethane and propane. High proportions of ethane and propane in the vent gas demonstrated that source of gas are thermogenic in origin. Patchy authigenic carbonate, bacterial mats, bivalves, tube worms and other chemosynthesis organisms were supported by venting gas AOM process near the sea floor. Pore water chloride concentrations show distinct variation pattern from center cone to the side of the volcano, with low in the center and high away from the cone. Pore water with higher than seawater

  6. 30 CFR 250.1160 - When may I flare or vent gas?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1160 When may I flare or vent gas? (a) You must...) When properly working equipment yields flash gas (natural gas released from liquid hydrocarbons as a... have avoided flaring or venting the gas, the hydrocarbons will be considered avoidably lost or...

  7. 30 CFR 250.1160 - When may I flare or vent gas?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1160 When may I flare or vent gas? (a) You must...) When properly working equipment yields flash gas (natural gas released from liquid hydrocarbons as a... have avoided flaring or venting the gas, the hydrocarbons will be considered avoidably lost or...

  8. 30 CFR 250.1160 - When may I flare or vent gas?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1160 When may I flare or vent gas? (a) You must...) When properly working equipment yields flash gas (natural gas released from liquid hydrocarbons as a... have avoided flaring or venting the gas, the hydrocarbons will be considered avoidably lost or...

  9. 30 CFR 250.1160 - When may I flare or vent gas?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., Venting, and Burning Hydrocarbons § 250.1160 When may I flare or vent gas? (a) You must request and...) When properly working equipment yields flash gas (natural gas released from liquid hydrocarbons as a... flaring or venting the gas, the hydrocarbons will be considered avoidably lost or wasted. You must...

  10. 76 FR 33179 - Petition Requesting Safeguards for Glass Fronts of Gas Vented Fireplaces

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-08

    ... COMMISSION 16 CFR 1460 Petition Requesting Safeguards for Glass Fronts of Gas Vented Fireplaces AGENCY: U.S... to require safeguards for glass fronts of gas vented fireplaces. We invite written comments... rulemaking to require safeguards for glass fronts of gas vented fireplaces. We are docketing this request...

  11. Fluid and gas fluxes from the Logatchev hydrothermal vent area

    NASA Astrophysics Data System (ADS)

    Schmale, Oliver; Walter, Maren; Schneider von Deimling, Jens; Sültenfuß, Jürgen; Walker, Sharon; Rehder, Gregor; Keir, Robin

    2012-07-01

    The Logatchev hydrothermal field at 14°45'N on the MAR is characterized by gas plumes that are enriched in methane and helium compared to the oceanic background. We investigated CH4 concentration and δ13C together with δ3He in the water column of that region. These data and turbidity measurements indicate that apart from the known vent fields, another vent site exists northeast of the vent field Logatchev 1. The distribution of methane and 3He concentrations along two sections were used in combination with current measurements from lowered acoustic Doppler current profilers (LADCP) to calculate the horizontal plume fluxes of these gases. According to these examinations 0.02 μmol s-1 of 3He and 0.21 mol s-1 of methane are transported in a plume that flows into a southward direction in the central part of the valley. Based on 3He measurements of vent fluid (22 ± 6 pM), we estimate a total vent flux in this region of about 900 L s-1 and a total flux of CH4 of 3.2 mol s-1.

  12. CFD analysis of gas explosions vented through relief pipes.

    PubMed

    Ferrara, G; Di Benedetto, A; Salzano, E; Russo, G

    2006-09-21

    Vent devices for gas and dust explosions are often ducted to safe locations by means of relief pipes. However, the presence of the duct increases the severity of explosion if compared to simply vented vessels (i.e. compared to cases where no duct is present). Besides, the identification of the key phenomena controlling the violence of explosion has not yet been gained. Multidimensional models coupling, mass, momentum and energy conservation equations can be valuable tools for the analysis of such complex explosion phenomena. In this work, gas explosions vented through ducts have been modelled by a two-dimensional (2D) axi-symmetric computational fluid dynamic (CFD) model based on the unsteady Reynolds Averaged Navier Stokes (RANS) approach in which the laminar, flamelet and distributed combustion models have been implemented. Numerical test have been carried out by varying ignition position, duct diameter and length. Results have evidenced that the severity of ducted explosions is mainly driven by the vigorous secondary explosion occurring in the duct (burn-up) rather than by the duct flow resistance or acoustic enhancement. Moreover, it has been found out that the burn-up affects explosion severity due to the reduction of venting rate rather than to the burning rate enhancement through turbulization.

  13. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 2 2010-07-01 2010-07-01 false When may I flare or vent gas for extended... Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1161 When may I flare or vent gas... flare or vent gas for an extended period of time. The Regional Supervisor will specify the...

  14. An authoritative global database for active submarine hydrothermal vent fields

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew

    2013-11-01

    The InterRidge Vents Database is available online as the authoritative reference for locations of active submarine hydrothermal vent fields. Here we describe the revision of the database to an open source content management system and conduct a meta-analysis of the global distribution of known active vent fields. The number of known active vent fields has almost doubled in the past decade (521 as of year 2009), with about half visually confirmed and others inferred active from physical and chemical clues. Although previously known mainly from mid-ocean ridges (MORs), active vent fields at MORs now comprise only half of the total known, with about a quarter each now known at volcanic arcs and back-arc spreading centers. Discoveries in arc and back-arc settings resulted in an increase in known vent fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. The purpose of the database now extends beyond academic research and education and into marine policy and management, with at least 18% of known vent fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.

  15. Causes and consequences of backdrafting of vented gas appliances.

    PubMed

    Nagda, N L; Koontz, M D; Billick, I H; Leslie, N P; Behrens, D W

    1996-09-01

    House depressurization occurs when household equipment such as a kitchen or bathroom fan or a fireplace exhausts air from the house and lowers the pressure indoors with respect to the outside. The operation of air handlers for forced-air heating or cooling systems also can have a depressurization effect. This depressurization can hinder the natural draft from vented combustion appliances and lead to backdrafting, which in turn can result in combustion gases spilling into the indoor airspace. Extensive spillage can cause elevated indoor levels of combustion products such as carbon dioxide (CO2) and water vapor, as well as contaminants such as carbon monoxide (CO) and nitrogen dioxide (NO2). The focus of this paper is to review studies on depressurization-induced backdrafting and spillage from gas-fired, drafthood equipped furnaces and domestic hot water heaters. Qualitative and quantitative techniques that were used in depressurization and backdrafting studies conducted in Canada, Europe, and the United States are analyzed. These studies have shown that exhaust fans operated simultaneously with fireplaces depressurize houses by 3 to 8 Pa on average. The CO indoor concentrations due to spillage, as reported in these studies, generally have been lower than 5 ppm. However, such low CO concentrations do not necessarily imply that a potential problem associated with backdrafting does not exist. Other combustion products, such as NO2, rarely have been measured in prior backdrafting studies. It can be concluded from the literature review that causes of house depressurization are well understood. However, more comprehensive research is needed to better understand the frequency, duration, and severity of depressurization-induced spillage in a broad cross section of houses. Efforts in this direction have begun recently in the United States through a workshop to define research issues, pilot studies to develop comprehensive measurement protocols, and consensus standard

  16. 30 CFR 250.1160 - When may I flare or vent gas?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Gas Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1160 When may I flare or... (natural gas released from liquid hydrocarbons as a result of a decrease in pressure, an increase in... negligent or could have avoided flaring or venting the gas, the hydrocarbons will be considered...

  17. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Gas Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1164 What are the requirements for flaring or venting gas containing H2S? (a) You may not vent gas containing H2S, except for... Supervisor may further restrict the flaring of gas containing H2S. The Regional Supervisor will...

  18. Unit vent airflow measurements using a tracer gas technique

    SciTech Connect

    Adams, D.G.; Lagus, P.L.; Fleming, K.M.

    1997-08-01

    An alternative method for assessing flowrates that does not depend on point measurements of air flow velocity is the constant tracer injection technique. In this method one injects a tracer gas at a constant rate into a duct and measures the resulting concentration downstream of the injection point. A simple equation derived from the conservation of mass allows calculation of the flowrate at the point of injection. Flowrate data obtained using both a pitot tube and a flow measuring station were compared with tracer gas flowrate measurements in the unit vent duct at the Callaway Nuclear Station during late 1995 and early 1996. These data are presented and discussed with an eye toward obtaining precise flowrate data for release rate calculations. The advantages and disadvantages of the technique are also described. In those test situations for which many flowrate combinations are required, or in large area ducts, a tracer flowrate determination requires fewer man-hours than does a conventional traverse-based technique and does not require knowledge of the duct area. 6 refs., 10 figs., 6 tabs.

  19. Distinctive Geomorphology of Gas Venting and Near Seafloor Gas Hydrate-Bearing sites

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Caress, D. W.; Lundsten, E.; Anderson, K.; Gwiazda, R.; McGann, M. L.; Edwards, B. D.; Riedel, M.; Herguera, J.

    2012-12-01

    High-resolution multibeam bathymetry and chirp seismic-reflection profiles collected with an Autonomous Underwater Vehicle (AUV) complimented by Remotely Operated Vehicle (ROV) observations and sampling reveal the fine scale geomorphology associated with gas venting and/or near subsurface gas hydrate accumulations along the Pacific North American continental margin (Santa Monica Basin, Hydrate Ridge, Eel River, Barkley Canyon, and Bullseye Vent) and along the transform faults in the Gulf of California. At the 1 m multibeam grid resolution of the new data, distinctive features and textures that are undetectable at lower resolution, show the impact of gas venting, gas hydrate development, and related phenomena on the seafloor morphology. Together a suite of geomorphic characteristics illustrates different stages in the development of seafloor gas venting systems. The more mature and/or impacted areas are associated with widespread exposures of methane-derived carbonates, which form broken and irregular seafloor pavements with karst-like voids in between the cemented blocks. These mature areas also contain elevated features >10 m high and circular seafloor craters with diameters of 3-50 m that appear to be associated with missing sections of the original seafloor. Smaller mound-like features (<10 m in diameter and 1-3 m higher than the surrounding seafloor) occur at multiple sites. Solid lenses of gas hydrate are occasionally exposed along fractures on the sides of these mounds and suggest that these are push-up features associated with gas hydrate growth within the near seafloor sediments. The youngest appearing features are associated with more-subtle (<3 m in diameter and ~0.5 m high) seafloor mounds, the crests of which are crossed with small cracks lined with white bacterial mats. ROV-collected (<1.5 m long) cores obtained from these subtle mounds encountered a hard layer at 30-60 cm sub-bottom. When this layer was penetrated, methane bubbles gushed out and

  20. Predicting Backdrafting and Spillage for Natural-Draft Gas Combustion Appliances: Validating VENT-II

    SciTech Connect

    Rapp, Vi H.; Pastor-Perez, Albert; Singer, Brett C.; Wray, Craig P.

    2013-04-01

    VENT-II is a computer program designed to provide detailed analysis of natural draft and induced draft combustion appliance vent-systems (i.e., furnace or water heater). This program is capable of predicting house depressurization thresholds that lead to backdrafting and spillage of combustion appliances; however, validation reports of the program being applied for this purpose are not readily available. The purpose of this report is to assess VENT-II’s ability to predict combustion gas spillage events due to house depressurization by comparing VENT-II simulated results with experimental data for four appliance configurations. The results show that VENT-II correctly predicts depressurizations resulting in spillage for natural draft appliances operating in cold and mild outdoor conditions, but not for hot conditions. In the latter case, the predicted depressurizations depend on whether the vent section is defined as part of the vent connector or the common vent when setting up the model. Overall, the VENTII solver requires further investigation before it can be used reliably to predict spillage caused by depressurization over a full year of weather conditions, especially where hot conditions occur.

  1. Design and Testing of a Shell-Flow Hollow-Fiber Venting Gas Trap

    NASA Technical Reports Server (NTRS)

    Bue, Grant C.; Cross, Cindy; Hansen, Scott; Vogel, Matthew; Dillon, Paul

    2013-01-01

    A Venting Gas Trap (VGT) was designed, built, and tested at NASA Johnson Space Center to eliminate dissolved and free gas from the circulating coolant loop of the Orion Environmental Control Life Support System. The VGT was downselected from two different designs. The VGT has robust operation, and easily met all the Orion requirements, especially size and weight. The VGT has a novel design with the gas trap made of a five-layer spiral wrap of porous hydrophobic hollow fibers that form a cylindrically shaped curtain terminated by a dome-shaped distal plug. Circulating coolant flows into the center of the cylindrical curtain and flows between the hollow fibers, around the distal plug, and exits the VGT outlet. Free gas is forced by the coolant flow to the distal plug and brought into contact with hollow fibers. The proximal ends of the hollow fibers terminate in a venting chamber that allows for rapid venting of the free gas inclusion, but passively limits the external venting from the venting chamber through two small holes in the event of a long-duration decompression of the cabin. The VGT performance specifications were verified in a wide range of flow rates, bubble sizes, and inclusion volumes. Long-duration and integrated Orion human tests of the VGT are also planned for the coming year.

  2. Gas Chemistry of Submarine Hydrothermal Venting at Maug Caldera, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Embley, R. W.; Lupton, J. E.; Butterfield, D. A.; Lilley, M. D.; Evans, L. J.; Olson, E. J.; Resing, J. A.; Buck, N.; Larson, B. I.; Young, C.

    2014-12-01

    Maug volcano consists of 3 islands that define the perimeter of a submerged caldera that was formed by an explosive eruption. The caldera reaches a depth of ~225 meters, and has a prominent central cone or pinnacle that ascends within 20 meters of the sea surface. Our exploration of Maug began in 2003, when a single hydrocast in the caldera detected a strong suspended particle and helium plume reaching a maximum of δ3He = 250% at ~180 meters depth, clearly indicating hydrothermal activity within the caldera. In 2004 we returned armed with the ROPOS ROV, and two ROPOS dives discovered and sampled low temperature (~4 °C) diffuse venting associated with bacterial mats on the NE flank of the central pinnacle at 145 m depth. Samples collected with titanium gas tight bottles were badly diluted with ambient seawater but allowed an estimate of end-member 3He/4He of 7.3 Ra. Four vertical casts lowered into the caldera in 2004 all had a strong 3He signal (δ3He = 190%) at 150-190 meters depth. A recent expedition in 2014 focused on the shallow (~10 m) gas venting along the caldera interior. Scuba divers were able to collect samples of the gas bubbles using evacuated SS bottles fitted with plastic funnels. The gas samples had a consistent ~170 ppm He, 8 ppmNe, 60% CO2, 40%N2, and 0.8% Ar, and an end-member 3He/4He ratio of 6.9 Ra. This 3He/4He ratio falls within the range for typical arc volcanoes. The rather high atmospheric component (N2, Ar, Ne) in these samples is not contamination but appears to be derived from subsurface exchange between the ascending CO2 bubbles and air saturated seawater. A single vertical cast in 2014 had a maximum δ3He = 55% at 140 m depth, much lower than in 2003 and 2004. This decrease is possibly due to recent flushing of the caldera by a storm event, or may reflect a decrease in the deep hydrothermal activity. This area of shallow CO2 venting in Maug caldera is of particular interest as a natural laboratory for studying the effects of ocean

  3. Venting of gas explosion through relief ducts: interaction between internal and external explosions.

    PubMed

    Ferrara, G; Willacy, S K; Phylaktou, H N; Andrews, G E; Di Benedetto, A; Salzano, E; Russo, G

    2008-06-30

    Relief ducts fitted to venting openings is a widespread configuration in the industrial practice. The presence of a duct has been reported to severely increase the violence of the vented explosion posing a problem for the proper design of the venting device. Several studies have reported the leading importance--in the whole complex explosion phenomenology--of a secondary explosion in the duct. Modern approaches in the study of simply vented explosions (without ducts) have focused on the study of the interaction between internal and external explosion as a key issue in the mechanisms of pressure generation. The issue is even more relevant when a duct is fitted to the vent due the confined nature of the external explosion. In this work the interaction between internal and external events is experimentally investigated for gas explosions vented through a relief duct. The work has aimed at studying mechanisms underlying the pressure rise of this venting configuration. The study has put the emphasis on the mutual nature of the interaction. A larger scale than laboratory has been investigated allowing drawing results with a greater degree of generality with respect to data so far presented in literature.

  4. Springs, streams, and gas vent on and near Mount Adams volcano, Washington

    USGS Publications Warehouse

    Nathenson, Manuel; Mariner, Robert H.

    2013-01-01

    Springs and some streams on Mount Adams volcano have been sampled for chemistry and light stable isotopes of water. Spring temperatures are generally cooler than air temperatures from weather stations at the same elevation. Spring chemistry generally reflects weathering of volcanic rock from dissolved carbon dioxide. Water in some springs and streams has either dissolved hydrothermal minerals or has reacted with them to add sulfate to the water. Some samples appear to have obtained their sulfate from dissolution of gypsum while some probably involve reaction with sulfide minerals such as pyrite. Light stable isotope data for water from springs follow a local meteoric water line, and the variation of isotopes with elevation indicate that some springs have very local recharge and others have water from elevations a few hundred meters higher. No evidence was found for thermal or slightly thermal springs on Mount Adams. A sample from a seeping gas vent on Mount Adams was at ambient temperature, but the gas is similar to that found on other Cascade volcanoes. Helium isotopes are 4.4 times the value in air, indicating that there is a significant component of mantle helium. The lack of fumaroles on Mount Adams and the ambient temperature of the gas indicates that the gas is from a hydrothermal system that is no longer active.

  5. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  6. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  7. 30 CFR 250.1161 - When may I flare or vent gas for extended periods of time?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... periods of time? 250.1161 Section 250.1161 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... I flare or vent gas for extended periods of time? You must request and receive approval from the Regional Supervisor to flare or vent gas for an extended period of time. The Regional Supervisor...

  8. 2D models of gas flow and ice grain acceleration in Enceladus' vents using DSMC methods

    NASA Astrophysics Data System (ADS)

    Tucker, Orenthal J.; Combi, Michael R.; Tenishev, Valeriy M.

    2015-09-01

    The gas distribution of the Enceladus water vapor plume and the terminal speeds of ejected ice grains are physically linked to its subsurface fissures and vents. It is estimated that the gas exits the fissures with speeds of ∼300-1000 m/s, while the micron-sized grains are ejected with speeds comparable to the escape speed (Schmidt, J. et al. [2008]. Nature 451, 685-688). We investigated the effects of isolated axisymmetric vent geometries on subsurface gas distributions, and in turn, the effects of gas drag on grain acceleration. Subsurface gas flows were modeled using a collision-limiter Direct Simulation Monte Carlo (DSMC) technique in order to consider a broad range of flow regimes (Bird, G. [1994]. Molecular Gas Dynamics and the Direct Simulation of Gas Flows. Oxford University Press, Oxford; Titov, E.V. et al. [2008]. J. Propul. Power 24(2), 311-321). The resulting DSMC gas distributions were used to determine the drag force for the integration of ice grain trajectories in a test particle model. Simulations were performed for diffuse flows in wide channels (Reynolds number ∼10-250) and dense flows in narrow tubular channels (Reynolds number ∼106). We compared gas properties like bulk speed and temperature, and the terminal grain speeds obtained at the vent exit with inferred values for the plume from Cassini data. In the simulations of wide fissures with dimensions similar to that of the Tiger Stripes the resulting subsurface gas densities of ∼1014-1020 m-3 were not sufficient to accelerate even micron-sized ice grains to the Enceladus escape speed. In the simulations of narrow tubular vents with radii of ∼10 m, the much denser flows with number densities of 1021-1023 m-3 accelerated micron-sized grains to bulk gas speed of ∼600 m/s. Further investigations are required to understand the complex relationship between the vent geometry, gas source rate and the sizes and speeds of ejected grains.

  9. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a) If your...

  10. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250... Production Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a)...

  11. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a) If your...

  12. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250... Requirements Flaring, Venting, and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a) If your...

  13. Post-drilling hydrothermal vent and associated biological activities seen through artificial hydrothermal vents in the Iheya North field, Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Takai, K.; Kawagucci, S.; Miyazaki, J.; Watsuji, T.; Ishibashi, J.; Yamamoto, H.; Nozaki, T.; Kashiwabara, T.; Shibuya, T.

    2012-12-01

    In 2010, IODP Expedition 331 was conducted in the Iheya North Field, the Okinawa Trough and drilled several sites in hydrothermally active subseafloor. In addition, during the IODP Expedition 331, four new hydrothermal vents were created. These post-drilling artificial hydrothermal vents provide excellent opportunities to investigate the physical, chemical and microbiological characteristics of the previously unexplored subseafloor hydrothermal fluid reservoirs, and to monitor and estimate how the anthropogenic drilling behaviors affect the deep-sea hydrothermal vent ecosystem. We were very much interested in the difference of hydrothermal fluid chemistry between the natural hydrothermal vents and the artificial hydrothermal vents. The IODP porewater chemistry of the cores pointed to the density-driven stratification of the phase-separated hydrothermal fluids and the natural vent fluids were likely derived only from the shallower vapor-enriched phases. However, the artificial hydrothermal vents had deeper fluid sources in the subseafloor hydrothermal fluid reservoirs composed of vapor-lost (Cl-enriched) phases. The fluids from the artificial hydrothermal vents were sampled by ROV at 5, 12 and 18 months after the IODP expedition. The artificial hydrothermal vent fluids were slightly enriched with Cl as compared to the natural hydrothermal vent fluids. Thus, the artificial hydrothermal vents successfully entrained the previously unexplored subseafloor hydrothermal fluids. The newly created hydrothermal vents also hosted the very quickly grown, enormous chimney structures, of which mineral compositions were highly variable among the vents. However, the quickly grown C0016B and C0016D vent chimneys were found to be typical Kuroko ore even though the chimney growth rates in the artificial vents were extremely faster than those in the natural vents. In addition, the IODP drilling operation not only created new hydrothermal vents by deep drilling but also induced the

  14. New mineral occurrences and mineralization processes: Wuda coal-fire gas vents of Inner Mongolia

    SciTech Connect

    Stracher, G.B.; Prakash, A.; Schroeder, P.; McCormack, J.; Zhang, X.M.; Van Dijk, P.; Blake, D.

    2005-12-01

    Five unique mineral assemblages that include the sulfates millosevichite, alunogen, anhydrite, tschermigite, coquimbite, voltaite, and godovikovite, as well as the halide salammoniac and an unidentified phase, according to X-ray diffraction and EDS data, were found as encrustations on quartzofeldspathic sand and sandstone adjacent to coal-fire gas vents associated with underground coal fires in the Wuda coalfield of Inner Mongolia. The mineral assemblage of alunogen, coquimbite, voltaite, and the unidentified phase collected front the same gas vent, is documented for the first time. Observations suggest that the sulfates millosevichite, alunogen, coquimbite, voltaite, godovikovite, and the unidentified phase, crystallized in response to a complex sequence of processes that include condensation, hydrothermal alteration, crystallization from solution, fluctuating vent temperatures, boiling, and dehydration reactions, whereas the halide salammoniac crystallized during the sublimation of coal-fire gas. Tschermigite and anhydrite formed by the reaction of coal-fire gas with quartzofelds pathic rock or by hydrothermal alteration of this rock and crystallization from an acid-rich aqueous solution. These minerals have potentially important environmental significance and may be vectors for the transmission of toxins. Coal fires also provide insight for the recognition in the geologic record of preserved mineral assemblages that are diagnostic of ancient fires.

  15. Technical note: In vitro total gas and methane production measurements from closed or vented rumen batch culture systems.

    PubMed

    Cattani, M; Tagliapietra, F; Maccarana, L; Hansen, H H; Bailoni, L; Schiavon, S

    2014-03-01

    This study compared measured gas production (GP) and computed CH4 production values provided by closed or vented bottles connected to gas collection bags. Two forages and 3 concentrates were incubated. Two incubations were conducted, where the 5 feeds were tested in 3 replicates in closed or vented bottles, plus 4 blanks, for a total of 64 bottles. Half of the bottles were not vented, and the others were vented at a fixed pressure (6.8 kPa) and gas was collected into one gas collection bag connected to each bottle. Each bottle (317 mL) was filled with 0.4000 ± 0.0010 g of feed sample and 60 mL of buffered rumen fluid (headspace volume = 257 mL) and incubated at 39.0°C for 24 h. At 24 h, gas samples were collected from the headspace of closed bottles or from headspace and bags of vented bottles and analyzed for CH4 concentration. Volumes of GP at 24 h were corrected for the gas dissolved in the fermentation fluid, according to Henry's law of gas solubility. Methane concentration (mL/100mL of GP) was measured and CH4 production (mL/g of incubated DM) was computed using corrected or uncorrected GP values. Data were analyzed for the effect of venting technique (T), feed (F), interaction between venting technique and feed (T × F), and incubation run as a random factor. Closed bottles provided lower uncorrected GP (-18%) compared with vented bottles, especially for concentrates. Correction for dissolved gas reduced but did not remove differences between techniques, and closed bottles (+25 mL of gas/g of incubated DM) had a greater magnitude of variation than did vented bottles (+1 mL of gas/g of incubated DM). Feeds differed in uncorrected and corrected GP, but the ranking was the same for the 2 techniques. The T × F interaction influenced uncorrected GP values, but this effect disappeared after correction. Closed bottles provided uncorrected CH4 concentrations 23% greater than that of vented bottles. Correction reduced but did not remove this difference. Methane

  16. Listening to Ambrym Volcano (Vanuatu) By an Acoustic Array: Cyclictity in Gas Volume at an Open Vent Volcano

    NASA Astrophysics Data System (ADS)

    Vergniolle, S.; Zielinski, C.; Bani, P.; Lardy, M.; LE Pichon, A.; Millier, P.; Herry, P.; Todman, S.; Garaebiti, E.

    2014-12-01

    Volcanic activity at Ambrym volcano (Vanuatu) is currently characterised by continuous lava lake activity within two main cones (Marum and Benbow), distant by 3 km. Acoustic measurements were performed by an acoustic array set at a distance of 3 km from the active vents between April 2009 and January 2010. The detection of volcanic signals, done by using PMCC (progressive multi-channel correlation), showed that more than 97 % of the detections came from one of the active vents, with millions of acoustic transients and no quiescent period. Two short Strombolian phases and 3 isolated explosions existed at Marum during this period while no strong signal was detected at Benbow. The active degassing, i.e. that detected by acoustic measurements, is mostly around 1 Hz at both vents. The gas volume is estimated from calculating acoustic power for each detection in the 0.8-2 Hz frequency range, assuming that the source has a constant radius of 5 m. The gas volume expelled per hour is similar at Benbow and Marum with 0.5-4 Mm^3. One striking observation is the existence of regular alternations between periods with high and small expelled gas volume, with 3 Mm^3 per hour and 0.5 Mm^3 per hour for each period, respectively. The detection of acoustic pulses even small, which is done with wavelet analysis, showed rapid and regular variations in the number of acoustic transients (1-460). The duration, return time and expelled gas volume were similar at Benbow and Marum on the 50 and 38 recognised cycles, respectively. The duration, return time and expelled gas volume at Benbow were equal to 58 hr, 70 hr and 42 Mm^3, respectively. Their relative small standart deviation for the above parameters, equal to 24 hr, 82 hr and 26 Mm^3 respectively, suggested that the fluctuations between periods with high and low gas volume, is probably cyclic. This 5 days-cyclicity could be perhaps be related to thermal convection processes in the magma reservoir.

  17. Springs, streams, and gas vent on and near Mount Adams volcano, Washington

    NASA Astrophysics Data System (ADS)

    Nathenson, M.; Mariner, R. H.

    2013-12-01

    air, indicating that there is a significant component of mantle helium. The lack of fumaroles on Mount Adams and the ambient temperature of the gas indicate that the gas is from a hydrothermal system that is no longer active. This is surprising, given the evidence for intense hydrothermal activity in the past. Of the major Cascade volcanoes, Mount Adams is the only one with no evidence for present hydrothermal discharge (Ingebritsen and Mariner, 2010). Ingebritsen, S.E., and Mariner, R.H., 2010, Hydrothermal heat discharge in the Cascade Range, northwestern United States: Journal of Volcanology and Geothermal Research, v. 196, p. 208-218. Nathenson, Manuel, and Mariner, R.H., 2013, Springs, streams, and gas vent on and near Mount Adams volcano, Washington: U.S. Geological Survey Scientific Investigations Report 2013-5097, 19 p., [Available on the Web at http://pubs.usgs.gov/sir/2013/5097/.

  18. Using Large Eddy Simulation for understanding vented gas explosions in the presence of obstacles.

    PubMed

    Di Sarli, Valeria; Di Benedetto, Almerinda; Russo, Gennaro

    2009-09-30

    In this work, a validated Large Eddy Simulation model of unsteady premixed flame propagation is used to study the phenomenology underlying vented gas explosions in the presence of obstacles. Computations are run of deflagrating flames in a small-scale combustion chamber closed at the bottom end and open at the opposite face. A single obstacle is centred inside the chamber. Methane-air mixtures of various compositions (ranging from lean to stoichiometric and rich), and obstacles with different area blockage ratios (30, 50 and 70%) and shapes (circular, rectangular and square cross-section in the flow direction) are investigated. All cases are initialized from stagnation. The competition between combustion rate and venting rate allows explaining both number and intensity of the overpressure peaks observed.

  19. Passive vs. active degassing modes at an open-vent volcano (Stromboli, Italy)

    NASA Astrophysics Data System (ADS)

    Tamburello, G.; Aiuppa, A.; Kantzas, E. P.; McGonigle, A. J. S.; Ripepe, M.

    2012-12-01

    We report here on a UV-camera based field experiment performed on Stromboli volcano during 7 days in 2010 and 2011, aimed at obtaining the very first simultaneous assessment of all the different forms (passive and active) of SO2 release from an open-vent volcano. Using the unprecedented spatial and temporal resolution of the UV camera, we obtained a 0.8 Hz record of the total SO2 flux from Stromboli over a timeframe of ∼14 h, which ranged between 0.4 and 1.9 kg s-1 around a mean value of 0.7 kg s-1 and we concurrently derived SO2 masses for more than 130 Strombolian explosions and 50 gas puffs. From this, we show erupted SO2 masses have a variability of up to one order of magnitude, and range between 2 and 55 kg (average ∼20 kg), corresponding to a time integrated flux of 0.05±0.01 kg s-1. Our experimental constraints on individual gas puff mass (0.03-0.42 kg of SO2, averaging 0.19 kg) are the first of their kind, equating to an emission rate ranging from 0.02 to 0.27 kg s-1. On this basis, we conclude that puffing is two times more efficient than Strombolian explosions in the magmatic degassing process, and that active degassing (explosions+puffing) accounts for ∼23% (ranging from 10% to 45%) of the volcano's total SO2 flux, e.g., passive degassing between the explosions contributes the majority (∼77%) of the released gas. We furthermore integrate our UV camera gas data for the explosions and puffs, with independent geophysical data (infrared radiometer data and very long period seismicity), to offer key and novel insights into the degassing dynamics within the shallow conduit systems of this open-vent volcano.

  20. Evidence of Extensive Gas Venting at the Blake Ridge and Cape Fear Diapirs

    NASA Astrophysics Data System (ADS)

    Brothers, L.; Van Dover, C. L.; German, C. R.; Yoerger, D. R.; Kaiser, C. L.; Lobecker, M.; Skarke, A. D.; Ruppel, C. D.

    2012-12-01

    seeps were found along 210 km of surveys conducted at the presumed upper edge of gas hydrate stability on the continental slope between Blake Ridge and the head of the Cape Fear slide. Nonetheless, the discovery of new seeps indicates abundant active methane escape along the southern portion of the US Atlantic Margin and calls for a reevaluation of the role of methane venting in regional seafloor processes there. In addition, these results triple the number of known cold seep communities along the US Atlantic margin, thus providing insight into biogeographic connectivity.

  1. Microphytobenthic community composition and primary production at gas and thermal vents in the Aeolian Islands (Tyrrhenian Sea, Italy).

    PubMed

    Rogelja, Manja; Cibic, Tamara; Pennesi, Chiara; De Vittor, Cinzia

    2016-07-01

    Sediment samplings were performed to investigate the microphytobenthic community and photosynthetic activity adaptations to gas emissions and higher temperature in the Aeolian Islands during a three-year period (2012-2014). Higher microphytobenthic densities were recorded at the vent stations and values were even more pronounced in relation with high temperature. The gross primary production estimates strongly depended on microphytobenthic abundance values reaching up to 45.79 ± 6.14 mgC m(-2) h(-1). High abundances were coupled with low community richness and diversity. Motile diatom living forms were predominant at all stations and the greatest differences among vent and reference stations were detected on the account of the tychopelagic forms. Morphological deformities and heavily silicified diatom frustules were also observed. A significant influence of the gas emission and high temperature on the phototrophic community was highlighted suggesting the Aeolian Islands as a good natural laboratory for studies on high CO2 and global warming effects.

  2. Gas hydrates and fluid venting in ultradeep large scale pockmarks at the southwest african margin off Congo

    NASA Astrophysics Data System (ADS)

    Spiess, V.; Kasten, S.; Schneider, R.; Zuehlsdorff, L.; Bohrmann, G.; Sahling, H.; Breitzke, M.; Bialas, J.; Ivanov, M.; Meteor Shipboard Scientific Party, M56.

    2003-04-01

    near feeder channels, which originate from shallow gas reservoirs at some hundred meters sub-bottom depth. The pockmark structures are furthermore associated with anomalies in temperature gradient. Sea floor sampling revealed in most cases several indicators of an active vent system as shallow, layered gas hydrates, carbonate precipitates and typical life forms.

  3. Aqueous Volatiles in Hydrothermal fluids from the Main Endeavour Vent Field: Temporal Variability Following Earthquake Activity

    NASA Astrophysics Data System (ADS)

    Seewald, J. S.; Cruse, A. M.; Saccocia, P. J.

    2001-12-01

    Volatile species play a critical role in a broad spectrum of physical, chemical, and biological processes associated with hydrothermal circulation at oceanic spreading centers. Earthquake activity at the Main Endeavour vent field, northern Juan de Fuca Ridge in June 1999 [1] provided and opportunity to assess factors that regulate the flux of volatile species from the oceanic crust to the water column following a rapid change in subsurface reaction zone conditions. High temperature vent fluids were collected in gas-tight samplers at the Main Endeavour field in September 1999, approximately four months after the earthquakes, and again in July 2000, and were analyzed for the abundance of aqueous volatile and non-volatile species. Measured concentrations of aqueous H2, H2S, and CO2 increased substantially in September 1999 relative to pre-earthquake values [2,3], and subsequently decreased in July 2000, while aqueous Cl concentrations initially decreased in 1999 and subsequently increased in 2000. Concentrations of Cl in all fluids were depleted relative to seawater values. Aqueous CH4 and NH3 concentrations decreased in both the 1999 and 2000 samples relative to pre- earthquake values. Variations in Cl concentration of Endeavour fluids reflect varying degrees of phase separation under near critical temperature and pressure conditions. Because volatile species efficiently partition into the vapor phase, variations in their abundance as a function of Cl concentration can be used to constrain conditions of phase separation and fluid-rock interaction. For example, concentrations of volatile species that are not readily incorporated into minerals (CH4 and NH3) correlated weakly with Cl suggesting phase separation was occurring under supercritical conditions after the earthquake activity. In contrast, compositional data for fluids prior to the earthquakes indicate a strong negative correlation between these species and Cl suggesting phase separation under subcritical

  4. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 2 2011-07-01 2011-07-01 false What are the requirements for flaring or venting gas containing H2S? 250.1164 Section 250.1164 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT....1163, and the following additional requirements: (1) For safety or air pollution prevention...

  5. 30 CFR 250.1163 - How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... volumes and liquid hydrocarbon burning volumes, and what records must I maintain? 250.1163 Section 250..., and Burning Hydrocarbons § 250.1163 How must I measure gas flaring or venting volumes and liquid hydrocarbon burning volumes, and what records must I maintain? (a) If your facility processes more than...

  6. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 2 2014-07-01 2014-07-01 false What are the requirements for flaring or venting gas containing H2S? 250.1164 Section 250.1164 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... analysis, under 30 CFR 550.303, to determine the potential effect of facility emissions. The...

  7. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 30 Mineral Resources 2 2012-07-01 2012-07-01 false What are the requirements for flaring or venting gas containing H2S? 250.1164 Section 250.1164 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... analysis, under 30 CFR 550.303, to determine the potential effect of facility emissions. The...

  8. 30 CFR 250.1164 - What are the requirements for flaring or venting gas containing H2S?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 30 Mineral Resources 2 2013-07-01 2013-07-01 false What are the requirements for flaring or venting gas containing H2S? 250.1164 Section 250.1164 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL... analysis, under 30 CFR 550.303, to determine the potential effect of facility emissions. The...

  9. Hydroacoustic Mapping of the Andaman Sea Shelf Break, Thailand - Indications for Slope Failures and Gas Venting

    NASA Astrophysics Data System (ADS)

    Jintasaeranee, P.; Weinrebe, W.; Klaucke, I.; Snidvongs, A.; Krastel, S.; Winkelmann, D.

    2008-12-01

    In order to assess the potential risk for tsunamis generated by submarine landsliding, the steepest parts of the Andaman Sea outer shelf and upper slope off the west coast of Thailand have been mapped hydro- acoustically during two recent cruises with RV Chakratong Tongyai. A multibeam echosounder and a parametric sediment echosounder were used to map the bathymetry and the thickness and structure of the uppermost sedimentary layers of hitherto unexplored areas in the Andaman Sea. An area of more than 3.000 km2 in the southwestern part of the Thai EEZ was successfully mapped. The data covered the upper shelf from about 500 m water depth down to about 1400 m. Generally the upper shelf has a gentle and smooth morphology whereas the lower slope is steeper and shows elongated escarpments striking parallel to subparallel to the shelf break, which might indicate a rather instable slope. Abundant indications of venting have also been found throughout the survey area and at various water depths. A mound shaped feature in about 550 m water depth associated with acoustic reflections in the water column document uprising gas bubbles. Several large pockmarks were mapped in the depth range of 600 m to 700 m which also indicate degassing. Negative polarity reflections, i.e. possible indications for shallow gas deposits are found in water depths of 800 m and more. All observations document that gas and/or fluids may be found in subsurface sediments throughout the area.

  10. The study of active submarine volcanoes and hydrothermal vents in the Southernmost Part of Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Lee, Y.; Tsai, C.; Lee, C.

    2004-12-01

    The study area is located in the Southernmost Part of Okinawa Trough (SPOT), which is a back-arc basin formed by extension of Eurasian plate. Previous research indicated two extensional stages in SPOT area. Many normal-fault structures were come into existence during both extensional processes. The SPOT is presently in an activity tectonic episode. Therefore, the area becomes a frequent earthquake and abundant magmatism. The purpose of this study is to discuss which relationship between tectonics, submarine volcanoes and hydrothermal vents in SPOT area. The investigations are continued from 1998 to 2004, we have found at least twelve active hydrothermal vents in study area. Compare the locations hydrothermal vents with fault systems, we find both of them have highly correlated. We can distinguish them into two shapes, pyramidal shape and non-pyramidal shape. According to plumes height, we are able to divide these vents into two groups near east longitude 122.5° . East of this longitude, the hydrothermal plumes are more powerful and west of it are the weaker. This is closely related to the present extensional axis (N80° E) of the southern part of the Okinawa Trough. This can be explained the reason of why the more powerful vents coming out of the east group. The east group is associated with the present back-arc spreading system. West of 122.5° , the spreading system are in a primary stage. The andesitic volcanic island, the Turtle Island, is a result of N60° E extensional tectonism with a lot of faults. Besides the pyramidal shape, this can be proved indirectly. The vents located in the west side were occurred from previous extensional faults and are weaker than the eastern. Therefore, we suggest that if last the extension keeps going on, the hydrothermal vents located at the west side of the longitude 122.5° will be intensified.

  11. 40 CFR 65.115 - Standards: Closed vent systems and control devices; or emissions routed to a fuel gas system or...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... control devices; or emissions routed to a fuel gas system or process. 65.115 Section 65.115 Protection of... Equipment Leaks § 65.115 Standards: Closed vent systems and control devices; or emissions routed to a fuel... operators of closed vent systems and nonflare control devices used to comply with provisions of this...

  12. Discovery of Nascent Vents and Recent Colonization Associated with(Re)activated Hydrothermal Vent Fields by the GALREX 2011 Expedition on the Galápagos Rift

    NASA Astrophysics Data System (ADS)

    Shank, T. M.; Holden, J. F.; Herrera, S.; Munro, C.; Muric, T.; Lin, J.; Stuart, L.

    2011-12-01

    GALREX 2011 was a NOAA OER telepresence cruise that explored the diverse habitats and geologic settings of the deep Galápagos region. The expedition made12 Little Hercules ROV dives in July 2011.Abundant corals and a strong depth zonation of species (including deepwater coral communities) were found near 500 m depth on Paramount Seamount, likely influenced by past low sea level states, wave-cut terrace processes, and the historical presence of shallow reef structures. At fresh lava flows with associated (flocculent) hydrothermal venting near 88° W, now known as Uka Pacha and Pegasus Vent Fields, rocks were coated with white microbial mat and lacked sessile fauna, with few mobile fauna (e.g., bythograeid crabs, alvinocarid shrimp, polynoid worms, zoarcid fish, and dirivultid copepods). This suggests a recent creation of hydrothermal habitats through volcanic eruptions and/or diking events, which may have taken place over a 15 km span separating the two vent fields. The Rosebud vent field at 86°W was not observed and may have been covered with lava since last visited in 2005. A hydrothermal vent field near 86°W was discovered that is one of the largest vent fields known on the Rift (120m by 40m). Low-temperature vent habitats were colonized by low numbers of tubeworms including Riftia, Oasisia, and a potential Tevnia species (the latter not previously observed on the Galapagos Rift). Patches of tubeworms were observed with individuals less than 2cm in length, and the relatively few large Riftia had tube lengths near 70cm long. Large numbers of small (< 3cm long) bathymodiolin mussels lined cracks and crevices throughout the active part of the field. Live clams, at least four species of gastropod limpets, three species of polynoid polychaetes, juvenile and adult alvinocarid shrimp, actinostolid anemones, and white microbial communities were observed on the underside and vertical surfaces of basalt rock surfaces. There were at least 13 species of vent-endemic fauna

  13. Sealing the deal? Vent dynamics and strombolian eruptions recorded with broadband seismic, acoustic and gas observations at Fuego Volcano, Guatemala

    NASA Astrophysics Data System (ADS)

    Lyons, J. J.; Waite, G. P.; Nadeau, P. A.

    2010-12-01

    interpretation. Initial results from a full waveform inversion in the VLP band suggest a shallow source and forward modeling is underway to constrain the source mechanism. We calculate apparent tilt by interpreting signals below the seismometer corner, from 600-100 s. Positive tilt increases in the radial direction from the summit for minutes prior to the surficial and acoustic expression of large explosions, suggesting inflation of the conduit. A sharp decrease in tilt occurs following explosions, implying a deflation of the conduit following the venting of volcanic gas and ash. Prior to explosions, UV camera data show decreasing trends in SO2 emission rate concurrent with conduit inflation. We propose that these data show an effective sealing of the vent, possibly due to microlite growth or precipitation of secondary minerals, and pressurization of the shallow conduit. Explosive degassing releases the overpressure, temporarily opens the vent and deflates the conduit. Multi-parameter observations of volcanic activity at various timescales greatly aids in interpreting eruption dynamics.

  14. Treatment of waste gas from the breather vent of a vertical fixed roof p-xylene storage tank by a trickle-bed air biofilter.

    PubMed

    Chang, Shenteng; Lu, Chungsying; Hsu, Shihchieh; Lai, How-Tsan; Shang, Wen-Lin; Chuang, Yeong-Song; Cho, Chi-Huang; Chen, Sheng-Han

    2011-01-01

    This study applied a pilot-scale trickle-bed air biofilter (TBAB) system for treating waste gas emitted from the breather vent of a vertical fixed roof storage tank containing p-xylene (p-X) liquid. The volatile organic compound (VOC) concentration of the waste gas was related to ambient temperature as well as solar radiation, peaking at above 6300 ppmv of p-X and 25000 ppmv of total hydrocarbons during the hours of 8 AM to 3 PM. When the activated carbon adsorber was employed as a VOC buffer, the peak waste gas VOC concentration was significantly reduced resulting in a stably and efficiently performing TBAB system. The pressure drop appeared to be low, reflecting that the TBAB system could be employed in the prolonged operation with a low running penalty. These advantages suggest that the TBAB system is a cost-effective treatment technology for VOC emission from a fixed roof storage tank.

  15. The roar of Yasur: Handheld audio recorder monitoring of Vanuatu volcanic vent activity

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.; Turtle, Elizabeth P.; Howell, Robert; Radebaugh, Jani; Lopes, Rosaly M. C.

    2016-08-01

    We describe how near-field audio recording using a pocket digital sound recorder can usefully document volcanic activity, demonstrating the approach at Yasur, Vanuatu in May 2014. Prominent emissions peak at 263 Hz, interpreted as an organ-pipe mode. High-pass filtering was found to usefully discriminate volcano vent noise from wind noise, and autocorrelation of the high pass acoustic power reveals a prominent peak in exhalation intervals of 2.5, 4 and 8 s, with a number of larger explosive events at 200 s intervals. We suggest that this compact and inexpensive audio instrumentation can usefully supplement other field monitoring such as seismic or infrasound. A simple estimate of acoustic power interpreted with a dipole jet noise model yielded vent velocities too low to be compatible with pyroclast emission, suggesting difficulties with this approach at audio frequencies (perhaps due to acoustic absorption by volcanic gases).

  16. Improvement of biohydrogen production from solid wastes by intermittent venting and gas flushing of batch reactors headspace.

    PubMed

    Valdez-Vazquez, Idania; Ríos-Leal, Elvira; Carmona-Martínez, Alessandro; Muñoz-Páez, Karla M; Poggi-Varaldo, Héctor M

    2006-05-15

    Headspace of batch minireactors was intermittently vented and gas flushed with N2 in order to enhance H2 production (PH) by anaerobic consortia degrading organic solid wastes. Type of inocula (meso and thermophilic), induction treatment (heat-shock pretreatment, HSP, and acetylene, Ac), and incubation temperature (37 and 55 degrees C) were studied by means of a factorial design. On average, it was found that mesophilic incubation had the most significant positive effect on PH followed by treatment with Ac, although the units with the best performance (high values of PH, initial hydrogen production rate, and short lag time) were those HSP-induced units incubated at 37 degrees C (type of inocula was not significant). In this way, after 720 h of incubation PH was inhibited in those units by H2 partial pressure (pH2) of 0.54 atm. Venting and gas flushing with N2 was efficient to eliminate that inhibition achieving additional hydrogen generation in subsequent incubation cycles although smaller than the first one. Thus, four cycles of PH were obtained from the same substrate with neither addition of inocula nor application of induction treatment obtaining an increment of 100% in the generated H2. In those subsequent cycles there was a positive correlation between PH and organic acids/solvent ratio; maximum values were found in the first cycle. Solventogenesis could be clearly distinguished in third and fourth production cycles, probably due to a metabolic shift originated by high organic acid concentrations.

  17. Antimicrobial Activity of Marine Bacterial Symbionts Retrieved from Shallow Water Hydrothermal Vents.

    PubMed

    Eythorsdottir, Arnheidur; Omarsdottir, Sesselja; Einarsson, Hjorleifur

    2016-06-01

    Marine sponges and other sessile macro-organisms were collected at a shallow water hydrothermal site in Eyjafjörður, Iceland. Bacteria were isolated from the organisms using selective media for actinomycetes, and the isolates were screened for antimicrobial activity. A total of 111 isolates revealed antimicrobial activity displaying different antimicrobial patterns which indicates production of various compounds. Known test strains were grown in the presence of ethyl acetate extracts from one selected isolate, and a clear growth inhibition of Staphylococcus aureus was observed down to 0.1 % extract concentration in the medium. Identification of isolates shows different species of Actinobacteria with Streptomyces sp. playing the largest role, but also members of Bacilli, Alphaproteobacteria and Gammaproteobacteria. Sponges have an excellent record regarding production of bioactive compounds, often involving microbial symbionts. At the hydrothermal vents, however, the majority of active isolates originated from other invertebrates such as sea anemones or algae. The results indicate that antimicrobial assays involving isolates in full growth can detect activity not visible by other methods. The macro-organisms inhabiting the Eyjafjörður hydrothermal vent area host diverse microbial species in the phylum Actinobacteria with antimicrobial activity, and the compounds responsible for the activity will be subject to further research.

  18. Chemosynthetic microbial activity at Mid-Atlantic Ridge hydrothermal vent sites

    NASA Astrophysics Data System (ADS)

    Wirsen, Carl O.; Jannasch, Holger W.; Molyneaux, Stephen J.

    1993-06-01

    Chemosynthetic production of microbial biomass, determined by 14CO2 fixation and enzymatic (RuBisCo) activity, at the Mid-Atlantic Ridge (MAR) 23° and 26°N vent sites was found in various niches: warm water emissions, loosely rock-attached flocculent material, dense morphologically diverse bacterial mats covering the surfaces of polymetal sulfide deposits, and filamentous microbes on the carapaces of shrimp (Rimicaris exoculata). The bacterial mats on polymetal sulfide surfaces contained unicellular and filamentous bacteria which appeared to use as their chemolithotrophic electron or energy source either dissolved reduced minerals from vent emissions, mainly sulfur compounds, or solid metal sulfide deposits, mainly pyrite. Moderately thermophilic Chemosynthetic activity was observed in carbon dioxide fixation experiments and in enrichments, but no thermophilic aerobic sulfur oxidizers could be isolated. Both obligate and facultative chemoautotrophs growing at mesophilic temperatures were isolated from all chemosynthetically active surface scrapings. The obligate autotrophs could oxidize sterilized MAR natural sulfide deposits as well as technical pyrite at near neutral pH, in addition to dissolved reduced sulfur compounds. While the grazing by shrimp on the surface mats of MAR metal sulfide deposits was observed and deemed important, the animals' primary occurrence in dense swarms near vent emissions suggests that they were feeding at these sites, where conditions for Chemosynthetic growth of their filamentous microbial epiflora were optimal. The data show that the transformation of geothermal energy at the massive polymetal sulfide deposits of the MAR is based on the lithoautotrophic oxidation of soluble sulfides and pyrites into microbial biomass.

  19. DISTINCTIVE FINE-SCALE MORPHOLOGY OF GAS-RICH SITES ON THE CASCADIA MARGIN NEAR BULLSEYE VENT

    NASA Astrophysics Data System (ADS)

    Thomas, H.; Paull, C. K.; Caress, D. W.; Ussler, W.; Lundsten, E.; Riedel, M.

    2009-12-01

    High-resolution multibeam bathymetry (vertical precision of 0.15 m and horizontal resolution of 1.0 m) and 2-10 kHz chirp seismic reflection profiles were recently collected over a small section of the Cascadia continental margin off British Columbia. The surveys were conducted using an autonomous underwater vehicle (AUV) and reveal in unprecedented detail fine-scale morphology and shallow seafloor structure. An inertial navigation system aided by a Doppler velocity log allows the AUV to fly pre-programmed grids with 150 m line spacing at 3 knots while maintaining an altitude of 50 m above the seafloor. The data were collected on three 17-hour-long dives in 1170 to 1410 m water depths focused on a 9.5 km long and ~3 km wide area on both sides of a node on the scientific research cable deployed by the Canadian Neptune Project. These surveys also cover the near seafloor associated with gas hydrate research boreholes at ODP Site 889/890, and IODP Site 1328 (Bullseye Vent). While the fine-scale texture of the seafloor is generally smooth throughout the surveyed area, there are notable exceptions. The crests of the tectonic ridges show a very distinctive hummocky topography. This topography is characterized by a highly irregular surface formed by small sometimes circular ~0.5 m deep pits, local highs and lows separated by ~0.5 m high ledges that could be formed by irregularly eroded bedding surfaces. Similar shapes also occur at larger scales including crater-like features that are up to 80 m across, raised rims, and more than 5 m deep central ‘crater’. A similar texture has been observed in other AUV surveys associated with methane-derived carbonate bearing sites known to overlie near seafloor gas hydrate deposits on Hydrate Ridge. Prior to this survey Bullseye Vent was believed to be associated with a roughly circular subtle topographic high (~2 m high) with a ~350 m diameter. The AUV data reveal Bullseye Vent to be a depression (~300 m long, ~70 m wide, up to 7 m

  20. A Comparison of Eddy Covariance and Static Vented Chamber Measurements of Greenhouse Gas Flux in Mid-South US Rice

    NASA Astrophysics Data System (ADS)

    Reba, M. L.; Fong, B.; Adviento-Borbe, M. A.; Linquist, B.

    2015-12-01

    Rice (Oryza sativa) production in the Lower Mississippi River Basin constitutes over 75% of US rice production, but little research has been done on water and greenhouse gas (GHG) flux in this region at the field scale. Measurements of these fluxes were made in 2014 from a 26.3 ha drill-seeded rice (CL XL 753) field. Eddy covariance measurements of water and carbon dioxide (CO2) and methane (CH4) fluxes allow for an integrated field measurement of the interaction between the landscape and the atmosphere. A static vented chamber technique was also used to measure fluxes of CO2, N2O (nitrous oxide) and CH4 in the same field on 19 occasions during the rice growing season. Estimates of GHG flux using static vented chamber were compared with the GHG fluxes from the eddy covariance method. These findings begin to address the increased interest in understanding agricultural impact on net GHG emission and consumption in an understudied region of the US. Future research might include similar data collection from multiple fields where water management is varied to measure its impact on net GHG flux.

  1. 75 FR 81950 - Flaring Versus Venting To Reduce Greenhouse Gas Emissions in the Outer Continental Shelf; Public...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-29

    ... assess the costs and benefits of requiring flare/vent meters and of requiring flaring instead of venting... instead of venting may be appropriate. However, the cost of implementing this requirement could be... directly with interested parties to study the costs and benefits (especially GHG benefits) of...

  2. Acoustic observations of gas bubble streams in the NW Black Sea as a method for estimation of gas flux from vent sites

    NASA Astrophysics Data System (ADS)

    Artemov, Yu. G.

    2003-04-01

    Relatively recent discovery of the natural CH_4 gas seepage from the sea bed had action upon the philosophy of CH_4 contribution to global budgets. So far as numerous gas vent sites are known, an acceptable method for released gas quantification is required. In particular, the questions should be answered as follows: 1) how much amount of gas comes into the water column due to a certain bubble stream, 2) how much amount of gas comes into the water column due to a certain seepage area of the see floor, 3) how much amount of gas diffuses into the water and how much gas phase enters the atmosphere. Echo-sounder is the habitual equipment for detecting gas plumes (flares) in the water column. To provide observations of gas seeps with bubbles tracking, single target and volume backscattering strength measurements, we use installed on board the R/V "Professor Vodyanitskiy" dual frequency (38 and 120 kHz) split-beam scientific echo-sounder SIMRAD EK-500. Dedicated software is developed to extract from the raw echo data and to handle the definite information for analyses of gas bubble streams features. This improved hydroacoustic techniques allows to determine gas bubbles size spectrum at different depths through the water column as well as rise velocity of bubbles of different sizes. For instance, bubble of 4.5 mm diameter has rising speed of 25.8 cm/sec at 105 m depth, while bubble of 1.7 mm diameter has rising speed of 16.3 cm/sec at 32 m depth. Using volume backscattering measurements in addition, it is possible to evaluate flux of the gas phase produced by methane bubble streams and to learn of its fate in the water column. Ranking of various gas plumes by flux rate value is available also. In this presentation results of acoustic observations at the shallow NW Black Sea seepage area are given.

  3. 78 FR 12772 - Information Collection Activities: Oil and Gas Production Requirements; Submitted for Office of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-25

    ... the information to: Evaluate requests to burn liquid hydrocarbons and vent and flare gas to ensure... replacement of gas meters to measure the amount of gas flared or vented. This is a non-hour cost burden. 1163... per month. 1163(b); Report to ONRR hydrocarbons produced, including measured gas flared/vented...

  4. Observations of Seafloor Deformation and Methane Venting within an Active Fault Zone Offshore Southern California

    NASA Astrophysics Data System (ADS)

    Anderson, K.; Lundsten, E. M.; Paull, C. K.; Caress, D. W.; Thomas, H. J.; Brewer, P. G.; Vrijenhoek, R.; Lundsten, L.

    2013-12-01

    Detailed mapping surveys of the floor and flanks of the Santa Monica Basin, San Pedro Basin, and San Diego Trough were conducted during the past seven years using an Autonomous Underwater Vehicle (AUV) built and operated by MBARI specifically for seafloor mapping. The AUV collected data provide up to 1 m resolution multibeam bathymetric grids with a vertical precision of 0.15 m. Along with high-resolution multibeam, the AUV also collects chirp seismic reflection profiles. Structures within the uppermost 10-20 m of the seafloor, which in the surveys presented here is composed of recent sediment drape, can typically be resolved in the sub-bottom reflectors. Remotely operated vehicle (ROV) dives allowed for ground-truth observations and sampling within the surveyed areas. The objectives of these dives included finding evidence of recent seafloor deformation and locating areas where chemosynthetic biological communities are supported by fluid venting. Distinctive seafloor features within an active fault zone are revealed in unprecedented detail in the AUV generated maps and seismic reflection profiles. Evidence for recent fault displacements include linear scarps which can be as small as 20 cm high but traceable for several km, right lateral offsets within submarine channels and topographic ridges, and abrupt discontinuities in sub-bottom reflectors, which in places appear to displace seafloor sediments. Several topographic highs that occur within the fault zone appear to be anticlines related to step-overs in these faults. These topographic highs are, in places, topped with circular mounds that are up to 15 m high and have ~30° sloping sides. The crests of the topographic highs and the mounds both have distinctive rough morphologies produced by broken pavements of irregular blocks of methane-derived authigenic carbonates, and by topographic depressions, commonly more than 2 m deep. These areas of distinctive rough topography are commonly associated with living

  5. Airbag vent valve and system

    NASA Technical Reports Server (NTRS)

    Peterson, Leslie D. (Inventor); Zimmermann, Richard E. (Inventor)

    2001-01-01

    An energy absorbing airbag system includes one or more vent valve assemblies for controlling the release of airbag inflation gases to maintain inflation gas pressure within an airbag at a substantially constant pressure during a ride-down of an energy absorbing event. Each vent valve assembly includes a cantilever spring that is flat in an unstressed condition and that has a free end portion. The cantilever spring is secured to an exterior surface of the airbag housing and flexed to cause the second free end portion of the cantilever spring to be pressed, with a preset force, against a vent port or a closure covering the vent port to seal the vent port until inflation gas pressure within the airbag reaches a preselected value determined by the preset force whereupon the free end portion of the cantilever spring is lifted from the vent port by the inflation gases within the airbag to vent the inflation gases from within the airbag. The resilience of the cantilever spring maintains a substantially constant pressure within the airbag during a ride-down portion of an energy absorbing event by causing the cantilever spring to vent gases through the vent port whenever the pressure of the inflation gases reaches the preselected value and by causing the cantilever spring to close the vent port whenever the pressure of the inflation gases falls below the preselected value.

  6. The Tiptop coal-mine fire, Kentucky: Preliminary investigation of the measurement of mercury and other hazardous gases from coal-fire gas vents

    USGS Publications Warehouse

    Hower, J.C.; Henke, K.; O'Keefe, J. M. K.; Engle, M.A.; Blake, D.R.; Stracher, G.B.

    2009-01-01

    The Tiptop underground coal-mine fire in the Skyline coalbed of the Middle Pennsylvanian Breathitt Formation was investigated in rural northern Breathitt County, Kentucky, in May 2008 and January 2009, for the purpose of determining the concentrations of carbon dioxide (CO2), carbon monoxide (CO), and mercury (Hg) in the vent and for measuring gas-vent temperatures. At the time of our visits, concentrations of CO2 peaked at 2.0% and > 6.0% (v/v) and CO at 600 ppm and > 700 ppm during field analysis in May 2008 and January 2009, respectively. For comparison, these concentrations exceed the U.S. Occupational Safety & Health Administration (OSHA) eight-hour safe exposure limits (0.5% CO2 and 50 ppm CO), although the site is not currently mined. Mercury, as Hg0, in excess of 500 and 2100 ??g/m3, in May and January, respectively, in the field, also exceeded the OSHA eight-hour exposure limit (50 ??g/m3). Carbonyl sulfide, dimethyl sulfide, carbon disulfide, and a suite of organic compounds were determined at two vents for the first sampling event. All gases are diluted by air as they exit and migrate away from a gas vent, but temperature inversions and other meteorological conditions could lead to unhealthy concentrations in the nearby towns. Variation in gas temperatures, nearly 300 ??C during the January visit to the fire versus < 50 ??C in May, demonstrates the large temporal variability in fire intensity at the Tiptop mine. These preliminary results suggest that emissions from coal fires may be important, but additional data are required that address the reasons for significant variations in the composition, flow, and temperature of vent gases. ?? 2009 Elsevier B.V.

  7. Prototype Vent Gas Heat Exchanger for Exploration EVA - Performance and Manufacturing Characteristics

    NASA Technical Reports Server (NTRS)

    Quinn, Gregory J.; Strange, Jeremy; Jennings, Mallory

    2013-01-01

    NASA is developing new portable life support system (PLSS) technologies, which it is demonstrating in an unmanned ground based prototype unit called PLSS 2.0. One set of technologies within the PLSS provides suitable ventilation to an astronaut while on an EVA. A new component within the ventilation gas loop is a liquid-to-gas heat exchanger to transfer excess heat from the gas to the thermal control system s liquid coolant loop. A unique bench top prototype heat exchanger was built and tested for use in PLSS 2.0. The heat exchanger was designed as a counter-flow, compact plate fin type using stainless steel. Its design was based on previous compact heat exchangers manufactured by United Technologies Aerospace Systems (UTAS), but was half the size of any previous heat exchanger model and one third the size of previous liquid-to-gas heat exchangers. The prototype heat exchanger was less than 40 cubic inches and weighed 2.57 lb. Performance of the heat exchanger met the requirements and the model predictions. The water side and gas side pressure drops were less 0.8 psid and 0.5 inches of water, respectively, and an effectiveness of 94% was measured at the nominal air side pressure of 4.1 psia.

  8. Prototype Vent Gas Heat Exchanger for Exploration EVA - Performance and Manufacturing Characteristics

    NASA Technical Reports Server (NTRS)

    Jennings, Mallory; Quinn, Gregory; Strange, Jeremy

    2012-01-01

    NASA is developing new portable life support system (PLSS) technologies, which it is demonstrating in an unmanned ground based prototype unit called PLSS 2.0. One set of technologies within the PLSS provides suitable ventilation to an astronaut while on an EVA. A new component within the ventilation gas loop is a liquid-to-gas heat exchanger to transfer excess heat from the gas to the thermal control system's liquid coolant loop. A unique bench top prototype heat exchanger was built and tested for use in PLSS 2.0. The heat exchanger was designed as a counter-flow, compact plate fin type using stainless steel. Its design was based on previous compact heat exchangers manufactured by United Technologies Aerospace Systems, but was half the size of any previous heat exchanger model and one third the size of previous liquid-to-gas heat exchangers. The prototype heat exchanger was less than 40 cubic inches and weighed 2.6 lb. The water side and gas side pressure drops were 0.8 psid and 0.5 inches of water, respectively. Performance of the heat exchanger at the nominal pressure of 4.1 psia was measured at 94%, while a gas inlet pressure of 25 psia resulted in an effectiveness of 84%. These results compared well with the model, which was scaled for the small size. Modeling of certain phenomena that affect performance, such as flow distribution in the headers was particularly difficult due to the small size of the heat exchanger. Data from the tests has confirmed the correction factors that were used in these parts of the model.

  9. METHANE EMISSIONS FROM THE NATURAL GAS INDUSTRY VOLUME 6: VENTED & COMBUSTION SOURCE SUMMARY

    EPA Science Inventory

    The 15-volume report summarizes the results of a comprehensive program to quantify methane (CH4) emissions from the U.S. natural gas 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...

  10. A kinetic model for the methane hydrate precipitated from venting gas at cold seep sites at Hydrate Ridge, Cascadia margin, Oregon

    NASA Astrophysics Data System (ADS)

    Cao, Yuncheng; Chen, Duofu; Cathles, Lawrence M.

    2013-09-01

    develop a kinetic model for hydrate crystallization from methane gas venting through shallow sediments at Hydrate Ridge on the Cascadia margin of Oregon that predicts how pore water chlorinity, temperature, and crystallized hydrate evolve after the onset of steady venting. Predictions are compared to observations at Ocean Drilling Program Site 1249. In the preferred model, calculated gas hydrate saturation and chloride concentrations reach those observed at depths less than 20 m below seafloor (bsf) under the southern summit of Hydrate Ridge in ~650 years, and the vertical water flux must be less than 50 kg/m2/yr. Hydrate accumulates more slowly between 20 m bsf and the base of the hydrate stability zone where there is no free gas, accumulating to observed levels of a few volume percent of hydrate in 105 to 106 years, depending on the water flux that is assumed through this zone. This dichotomy means that the presently observed gas venting must have been diverted to this area ~650 years ago, or be episodic and infrequent. If the gas venting for the last 650 years has been as observed today, the latent heat of hydrate precipitation in the upper 20 m of sediments would have caused the temperature to increase ~0.8°C at ~20 m bsf and ~0.2°C at ~100 m bsf. This would have caused a ~5 m rise in the elevation of the base of hydrate stability zone, and decreased the rate of hydrate crystallization from 1.5 kg CH4/m2/yr 650 years ago to 0.7 kg CH4/m2/yr today.

  11. Hydroacoustic quantification of free-gas venting offshore Svalbard, Arctic: Changes in space and time

    NASA Astrophysics Data System (ADS)

    Greinert, J.; Veloso, M.; De Batist, M. A.; Mienert, J.

    2013-12-01

    Hydroacoustic data from a seep site area offshore Spitsbergen have been collected since 2009 by RV Helmer Hanssen (U. Tromsoe) in order to monitor the dynamics of gas bubble seepage and evaluate the amount of CH4 released at the seafloor. A large number of acoustic flares have been detected during four years of data acquisition at an intensely seeping area close to the shelf edge in 240m water depth and further down-slope between 330 and 450m water depth covering the top of the gas hydrate stability zone. Water column data were collected with an EK60 split-beam echosounder system. Seep positions were determined by accounting for motion and using split-beam information to determine the ';flare spine' for seep location as accurately as possible. The inverse hydroacoustic method for flux estimation developed by Muyakshin et al. (2010) has been adapted to be used with the angle information derived from split-beam data and using gridding algorithms for generating acoustic maps for each of the four surveys. The method evaluates the flux using the backscattering volume strength (SV) above the seafloor produced by free gas release, a bubble size distribution (BSD) function obtained from video footage and models for bubble rising speed (BRS) taken from the literature. Methane flux calculations depending on these input parameters vary from 187 T/yr to 250 T/yr assuming a continuous discharge for the 240m deep shelf-edge site, when all data sets are merged. Compared to other fluxes e.g. from specific seep areas in the Black Sea (683 T/yr Greinert et al., 2010 JGR; 1376 T/yr Römer et al., 2012 MarGeo) or the Håkon Mosby mud volcano (181 T/yr Sauter et al., 2006 EPSL) the fluxes from offshore Svalbard are similar in range but on the lower end. However, studying the ';common area' which was insonified during all four years reveals a decreasing flux of about 20% although the actual seep positions have been very persistent. The reason for this is currently unknown. The

  12. A reduced crustal magnetization zone near the first observed active hydrothermal vent field on the Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Zhu, Jian; Lin, Jian; Chen, Yongshun J.; Tao, Chunhui; German, Christopher R.; Yoerger, Dana R.; Tivey, Maurice A.

    2010-09-01

    Inversion of near-bottom magnetic data reveals a well-defined low crustal magnetization zone (LMZ) near a local topographic high (37°47‧S, 49°39‧E) on the ultraslow-spreading Southwest Indian Ridge (SWIR). The magnetic data were collected by the autonomous underwater vehicle ABE on board R/V DaYangYiHao in February-March 2007. The first active hydrothermal vent field observed on the SWIR is located in Area A within and adjacent to the LMZ at the local topographic high, implying that this LMZ may be the result of hydrothermal alteration of magnetic minerals. The maximum reduction in crustal magnetization is 3 A/M. The spatial extent of the LMZ is estimated to be at least 6.7 × 104 m2, which is larger than that of the LMZs at the TAG vent field on the Mid-Atlantic Ridge (MAR), as well as the Relict Field, Bastille, Dante-Grotto, and New Field vent-sites on the Juan de Fuca Ridge (JdF). The calculated magnetic moment, i.e., the product of the spatial extent and amplitude of crustal magnetization reduction is at least -3 × 107 Am2 for the LMZ on the SWIR, while that for the TAG field on the MAR is -8 × 107 Am2 and that for the four individual vent fields on the JdF range from -5 × 107 to -3 × 107 Am2. Together these results indicate that crustal demagnetization is a common feature of basalt-hosted hydrothermal vent fields at mid-ocean ridges of all spreading rates. Furthermore, the crustal demagnetization of the Area A on the ultraslow-spreading SWIR is comparable in strength to that of the TAG area on the slow-spreading MAR.

  13. Coil spring venting arrangement

    DOEpatents

    McCugh, R.M.

    1975-10-21

    A simple venting device for trapped gas pockets in hydraulic systems is inserted through a small access passages, operated remotely, and removed completely. The device comprises a small diameter, closely wound coil spring which is pushed through a guide temporarily inserted in the access passage. The guide has a central passageway which directs the coil spring radially upward into the pocket, so that, with the guide properly positioned for depth and properly oriented, the coil spring can be pushed up into the top of the pocket to vent it. By positioning a seal around the free end of the guide, the spring and guide are removed and the passage is sealed.

  14. Flammability limits of lithium-ion battery thermal runaway vent gas in air and the inerting effects of halon 1301

    NASA Astrophysics Data System (ADS)

    Karp, Matthew Eugene

    Lithium-ion (rechargeable) and lithium-metal (non-rechargeable) battery cells put aircraft at risk of igniting and fueling fires. Lithium batteries can be packed in bulk and shipped in the cargo holds of freighter aircraft; currently lithium batteries are banned from bulk shipment on passenger aircraft [1]. The federally regulated Class C cargo compartment extinguishing system's utilization of a 5 %vol Halon 1301 knockdown concentration and a sustained 3 %vol Halon 1301 may not be sufficient at inerting lithium-ion battery vent gas and air mixtures [2]. At 5 %vol Halon 1301 the flammability limits of lithium-ion premixed battery vent gas (Li-Ion pBVG) in air range from 13.80 %vol to 26.07 %vol Li-Ion pBVG. Testing suggests that 8.59 %vol Halon 1301 is required to render all ratios of the Li-Ion pBVG in air inert. The lower flammability limit (LFL) and upper flammability limit (UFL) of hydrogen and air mixtures are 4.95 %vol and 76.52 %vol hydrogen, respectively. With the addition of 10 %vol and 20 %vol Halon 1301 the LFL is 9.02 %vol and 11.55 %vol hydrogen, respectively, and the UFL is 45.70 %vol and 28.39 %vol hydrogen, respectively. The minimum inerting concentration (MIC) of Halon 1301 in hydrogen and air mixtures is 26.72 %vol Halon 1301 at 16.2 %vol hydrogen. The LFL and UFL of Li-Ion pBVG and air mixtures are 7.88 %vol and 37.14 %vol Li-Ion pBVG, respectively. With the addition of 5 %vol, 7 %vol, and 8 %vol Halon 1301 the LFL is 13.80 %vol, 16.15 %vol, and 17.62 % vol Li-Ion pBVG, respectively, and the UFL is 26.07 %vol, 23.31 %vol, and 21.84 %vol Li- Ion pBVG, respectively. The MIC of Halon 1301 in Li-Ion pBVG and air mixtures is 8.59 %vol Halon 1301 at 19.52 %vol Li-Ion pBVG. Le Chatelier's mixing rule has been shown to be an effective measure for estimating the flammability limits of Li-Ion pBVGes. The LFL has a 1.79 % difference while the UFL has a 4.53 % difference. The state of charge (SOC) affects the flammability limits in an apparent parabolic

  15. First hydroacoustic evidence of marine, active fluid vents in the Naples Bay continental shelf (Southern Italy)

    NASA Astrophysics Data System (ADS)

    Passaro, Salvatore; Genovese, Simona; Sacchi, Marco; Barra, Marco; Rumolo, Paola; Tamburrino, Stella; Mazzola, Salvatore; Basilone, Gualtiero; Placenti, Francesco; Aronica, Salvatore; Bonanno, Angelo

    2014-09-01

    We present the first results of a multidisciplinary research aimed at the detection and mapping of Active Fluid Vents (AFVs) at the seafloor of the Naples Bay, Italy. This segment of the Campania continental margin is characterised by severe Quaternary extension and intense volcanism at Ischia and Procida islands, the Campi Flegrei and Somma-Vesuvius volcanic complexes. High resolution hydroacoustic profilers were used to identify and localize fluid emission from the seafloor. ROV direct observation showed that each emission centre is generally composed by the coalescence of several emitting points. CTD probes showed that there are no significant gradients in temperature profiles. The results of this study include the detection and mapping of 54 fluid emission points all located in the - 71/- 158 m depth range, and spatially distributed into four main clusters. Three of the described clusters are located along the margin of a complex, toe-shaped seafloor morphology southwest of the Somma-Vesuvius, representing the shallow expression of partly buried, coalesced depositional features (namely, two flank collapses and one pyroclastic flow) associated with the Late Pleistocene activity of the volcano. The fourth AFV cluster was detected at the morphological - high, located about 8 km south of Naples (Banco della Montagna), represented by a field of volcaniclastic diapirs composed of massive pumiceous deposits originated from the Campi Flegrei intruding rising through the latest Quaternary-Holocene marine deposits. Our study suggests that the occurrence of AFV in this area could be genetically linked to the interaction between volcanic related seafloor morphologies and the main, NE striking faults present in the area, i.e. the Magnaghi-Sebeto line and the Vesuvian fault.

  16. Biogeography and biodiversity in sulfide structures of active and inactive vents at deep-sea hydrothermal fields of the Southern Mariana Trough.

    PubMed

    Kato, Shingo; Takano, Yoshinori; Kakegawa, Takeshi; Oba, Hironori; Inoue, Kazuhiko; Kobayashi, Chiyori; Utsumi, Motoo; Marumo, Katsumi; Kobayashi, Kensei; Ito, Yuki; Ishibashi, Jun-ichiro; Yamagishi, Akihiko

    2010-05-01

    The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive vents were investigated by culture-independent methods. These sulfide structures were collected at four hydrothermal fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active vents. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive vents. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of hydrothermal activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive vents are likely to be comparable to or higher than those in active vent structures, even though the microbial community composition is different between these two types of vents. The microbial community compositions in the sulfide structures of inactive vents were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active vents, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and

  17. Vented Capacitor

    DOEpatents

    Brubaker, Michael Allen; Hosking, Terry Alan

    2006-04-11

    A technique of increasing the corona inception voltage (CIV), and thereby increasing the operating voltage, of film/foil capacitors is described. Intentional venting of the capacitor encapsulation improves the corona inception voltage by allowing internal voids to equilibrate with the ambient environment.

  18. Noble Gas geochemistry of the newly discovered hydrothermal fields in the Gulf of California: preliminary He-isotope ratios from the Alarcon Rise and Pescadero basin vent sites

    NASA Astrophysics Data System (ADS)

    Spelz, R. M.; Lupton, J. E.; Evans, L. J.; Zierenberg, R. A.; Clague, D. A.; Neumann, F.; Paduan, J. B.

    2015-12-01

    Numerous submarine deep-sea hydrothermal vents related to volcanic activity of the East Pacific Rise (EPR) are situated along the Pacific margins of Mexico. Until recently, active hydrothermal venting was unknown between the Guaymas Basin and 21°N on the EPR. MBARI's recent oceanographic surveys have added 7 new active vent sites. In this study, we aimed to sample the high-temperature hydrothermal fluids emanating from two distinct vent sites, named Meyibo and Auka, located in the Alarcon Rise and Pescadero Basin, respectively. Mantle-derived He have long been identified in hydrothermal fluid releases. The presence of He in aqueous fluids with 3He/4He ratios greater than in-situ production values (~0.05 RA, where RA = air He or 1.4 x 10-6) indicates the presence of mantle-derived melts. Preliminary analyses of He-isotope ratios derived from the newly discovered Meyibo and Auka hydrothermal fields show high 3He/4He ratios (~8RA), typical of MORB's. Auka vent field, characterized by chimneys composed of light carbonate minerals and oil-like hydrocarbons, and temperatures between 250-290oC, show average values of ~7.87RA. In contrast, the black-smokers at the Meyibo field, composed of dark sulfide minerals and temperatures over 350oC, yielded a higher He ratio of ~8.24RA. Recently, it has become clear that regional maximum mantle He values correlate with the velocity structure in the mantle, therefore, He has the potential to map regions of the underlying mantle that are undergoing partial melting. Seismic records could then be compared with the geochemical He ratio signal and supply information regarding tectonics and other processes involved in the generation of these gases. The data presented here will be completing a totally new inventory of He results from hydrothermal vents in the EPR and fault-termination basins distributed along the P-NA plate boundary in the Gulf of California. The results will be further coupled with the analysis of other geochemical

  19. Molecular Diversity and Activity of Methanogens in the Subseafloor at Deep-Sea Hydrothermal Vents of the Pacific Ocean (Invited)

    NASA Astrophysics Data System (ADS)

    Huber, J. A.; Merkel, A.; Holden, J. F.; Lilley, M. D.; Butterfield, D. A.

    2009-12-01

    Methanogenesis is thought to represent one of the most ancient metabolic pathways on Earth, and methanogens may serve as important primary producers in warm crustal habitats at deep-sea hydrothermal vents. Many of these obligate chemolithoautotrophs depend solely on geochemically-derived energy and carbon sources and grow at high temperatures under strictly anaerobic conditions. A combined geochemical and microbiological approach was used to determine the distribution and molecular diversity of methanogens in low temperature diffuse vent fluids from the Endeavour Segment R2K ISS site, as well as Axial Seamount and volcanoes of the Mariana Arc. Geochemical data from hot and adjacent warm diffuse vent fluids provided chemical indicators to guide sample selection for detailed polymerase chain reaction (PCR)-based analysis of the key enzyme for methane formation, methyl-coenzyme M reductase (mcrA), as well as archaeal 16S rRNA genes. At most Endeavour vent sites, hydrogen concentrations were too low to support hydrogenotrophic methanogensis directly and only one diffuse site, Easter Island, had a positive signal for the mcrA gene. These sequences were most closely related to members of the order Methanococcales, as well as anaerobic methane oxidizers (ANME-1). The presence of ANME, which are rarely found in non-sedimented marine environments, is another line of evidence supporting the occurrence of buried sediments at Endeavour. At Axial, a number of diffuse vents have strong chemical indicators of methanogenesis. Methanogenic communities were detected at 3 sites on the southeast side of the caldera: the northern end of the 1998 lava flow, the International District, and on the pre-1987 lava flow. Time series work at Marker 113 showed that in 4 different years over the last 6 years methanogenic communities are active and abundant, suggesting a stable anaerobic, warm subseafloor habitat. Results show that members of the order Methanococcales dominate at this site

  20. Distribution, activity and function of short-chain alkane degrading phylotypes in hydrothermal vent sediments

    NASA Astrophysics Data System (ADS)

    Adams, M. M.; Joye, S. B.; Hoarfrost, A.; Girguis, P. R.

    2012-12-01

    Global geochemical analyses suggest that C2-C4 short chain alkanes are a common component of the utilizable carbon pool in deep-sea sediments worldwide and have been found in diverse ecosystems. From a thermodynamic standpoint, the anaerobic microbial oxidation of these aliphatic hydrocarbons is more energetically yielding than the anaerobic oxidation of methane (AOM). Therefore, the preferential degradation of these hydrocarbons may compete with AOM for the use of oxidants such as sulfate, or other potential oxidants. Such processes could influence the fate of methane in the deep-sea. Sulfate-reducing bacteria (SRB) from hydrocarbon seep sediments of the Gulf of Mexico and Guaymas Basin have previously been enriched that anaerobically oxidize short chain alkanes to generate CO2 with the preferential utilization of 12C-enriched alkanes (Kniemeyer et al. 2007). Different temperature regimens along with multiple substrates were tested and a pure culture (deemed BuS5) was isolated from mesophilic enrichments with propane or n-butane as the sole carbon source. Through comparative sequence analysis, strain BuS5 was determined to cluster with the metabolically diverse Desulfosarcina / Desulfococcus cluster, which also contains the SRB found in consortia with anaerobic, methane-oxidizing archaea in seep sediments. Enrichments from a terrestrial, low temperature sulfidic hydrocarbon seep also corroborated that propane degradation occurred with most bacterial phylotypes surveyed belonging to the Deltaproteobacteria, particularly Desulfobacteraceae (Savage et al. 2011). To date, no microbes capable of ethane oxidation or anaerobic C2-C4 alkane oxidation at thermophilic temperature have been isolated. The sediment-covered, hydrothermal vent systems found at Middle Valley (Juan de Fuca Ridge, eastern Pacific Ocean) are a prime environment for investigating mesophilic to thermophilic anaerobic oxidation of short-chain alkanes, given the elevated temperatures and dissolved

  1. Development and field application of a 6-bottle serial gas-tight fluid sampler for collecting seafloor cold seep and hydrothermal vent fluids with autonomous operation capability

    NASA Astrophysics Data System (ADS)

    Wu, S.; Ding, K.; Yang, C.; Seyfried, W. E., Jr.; Tan, C.; Schaen, A. T.; Luhmann, A. J.

    2014-12-01

    A 6-bottle serial gas-tight sampler (so-called "six-shooter") was developed for application with deep-sea vent fluids. The new device is composed of a custom-made 6-channel valve manifold and six sampling bottles which are circularly distributed around the valve manifold. Each valve channel consists of a high-pressure titanium cartridge valve and a motor-driven actuator. A sampling snorkel is connected to the inlet of the manifold that delivers the incoming fluid to different bottles. Each sampling bottle has a 160 ml-volume chamber and an accumulator chamber inside where compressed nitrogen is used to maintain the sample at near in-situ pressure. An electronics chamber that is located at the center of the sampler is used to carry out all sampling operations, autonomously, if desired. The sampler is of a compact circular configuration with a diameter of 26 cm and a length of 54 cm. During the SVC cruise AT 26-12, the sampler was deployed by DSV2 Alvin at a cold seep site MC036 with a depth of 1090 m in the Gulf of Mexico. The sampler collected fluid samples automatically following the tidal cycle to monitor the potential impact of the tide cycle on the fluid chemistry of cold seep in a period of two day. During the cruise AT 26-17, the sampler was used with newly upgraded DSV2 Alvin three times at the hydrothermal vent sites along Axial Seamount and Main Endeavor Field on Juan de Fuca Ridge. During a 4-day deployment at Anemone diffuse site (Axial Caldera), the sampler was set to work in an autonomous mode to collect fluid samples according to the preset interval. During other dives, the sampler was manually controlled via ICL (Inductively Coupled Link) communication through the hull. Gas-tight fluid samples were collected from different hydrothermal vents with temperatures between 267 ℃ and 335 ℃ at the depth up to 2200 m. The field results indicate unique advantages of the design. It can be deployed in extended time period with remote operation or working

  2. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Venting system flow capacity. 153.358 Section 153.358... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any...

  3. Speed of collapse of the non-ventilated lung during single-lung ventilation for thoracoscopic surgery: the effect of transient increases in pleural pressure on the venting of gas from the non-ventilated lung.

    PubMed

    Pfitzner, J; Peacock, M J; Harris, R J

    2001-10-01

    A study of 10 anaesthetised patients placed in the lateral position for thoracoscopic surgery assessed whether transient increases in pleural pressure on the side of the non-ventilated lung might increase the speed at which gas vents from that lung. The transient increases in pleural pressure were generated by the mediastinal displacement that occurs with each inspiratory phase of positive pressure ventilation of the dependent lung. When combined with a unidirectional valve allowing gas to flow out of the non-ventilated lung, and a second valve allowing ambient airflow into, but not out of, the thoracic cavity via an initial thoracoscopy access site, this mediastinal displacement could conceivably serve to 'pump' gas out of the non-ventilated lung. Using the four different combinations of valve inclusion or omission, the volume of gas that vented from the non-ventilated lung into a measuring spirometer was recorded during a 120-s measurement sequence. It was found that the speed of venting was not increased by the transient increases in pleural pressure, and that in all but one of a total of 34 measurement sequences, venting had ceased by the end of the sequence. Gas venting was a mean (SD) of 85.5 (11.9)% complete in 25 s (five breaths), and 96.6 (6.1)% complete in 60 s. This prompt partial lung collapse very likely reflected the passive elastic recoil of the lung, while the failure of transient increases in pleural pressure to result in ongoing venting of gas was probably a consequence of airways closure as the lung collapsed. It is concluded that techniques that aim to speed lung collapse by increasing pleural pressure are unlikely to be effective.

  4. Reduction of Carbon Dioxide in Filtering Facepiece Respirators with an Active-Venting System: A Computational Study.

    PubMed

    Birgersson, Erik; Tang, Ee Ho; Lee, Wei Liang Jerome; Sak, Kwok Jiang

    2015-01-01

    During expiration, the carbon dioxide (CO2) levels inside the dead space of a filtering facepiece respirator (FFR) increase significantly above the ambient concentration. To reduce the CO2 concentration inside the dead space, we attach an active lightweight venting system (AVS) comprising a one-way valve, a blower and a battery in a housing to a FFR. The achieved reduction is quantified with a computational-fluid-dynamics model that considers conservation of mass, momentum and the dilute species, CO2, inside the FFR with and without the AVS. The results suggest that the AVS can reduce the CO2 levels inside the dead space at the end of expiration to around 0.4% as compared to a standard FFR, for which the CO2 levels during expiration reach the same concentration as that of the expired alveolar air at around 5%. In particular, during inspiration, the average CO2 volume fraction drops to near-to ambient levels of around 0.08% with the AVS. Overall, the time-averaged CO2 volume fractions inside the dead space for the standard FFR and the one with AVS are around 3% and 0.3% respectively. Further, the ability of the AVS to vent the dead-space air in the form of a jet into the ambient - similar to the jets arising from natural expiration without a FFR - ensures that the expired air is removed and diluted more efficiently than a standard FFR.

  5. Reduction of Carbon Dioxide in Filtering Facepiece Respirators with an Active-Venting System: A Computational Study

    PubMed Central

    Birgersson, Erik; Tang, Ee Ho; Lee, Wei Liang Jerome; Sak, Kwok Jiang

    2015-01-01

    During expiration, the carbon dioxide (CO2) levels inside the dead space of a filtering facepiece respirator (FFR) increase significantly above the ambient concentration. To reduce the CO2 concentration inside the dead space, we attach an active lightweight venting system (AVS) comprising a one-way valve, a blower and a battery in a housing to a FFR. The achieved reduction is quantified with a computational-fluid-dynamics model that considers conservation of mass, momentum and the dilute species, CO2, inside the FFR with and without the AVS. The results suggest that the AVS can reduce the CO2 levels inside the dead space at the end of expiration to around 0.4% as compared to a standard FFR, for which the CO2 levels during expiration reach the same concentration as that of the expired alveolar air at around 5%. In particular, during inspiration, the average CO2 volume fraction drops to near-to ambient levels of around 0.08% with the AVS. Overall, the time-averaged CO2 volume fractions inside the dead space for the standard FFR and the one with AVS are around 3% and 0.3% respectively. Further, the ability of the AVS to vent the dead-space air in the form of a jet into the ambient – similar to the jets arising from natural expiration without a FFR – ensures that the expired air is removed and diluted more efficiently than a standard FFR. PMID:26115090

  6. Risk-Free Volcano Observations Using an Unmanned Autonomous Helicopter: seismic observations near the active vent of Sakurajima volcano, Japan

    NASA Astrophysics Data System (ADS)

    Ohminato, T.; Kaneko, T.; Koyama, T.; Yasuda, A.; Watanabe, A.; Takeo, M.; Honda, Y.; Kajiwara, K.; Kanda, W.; Iguchi, M.; Yanagisawa, T.

    2010-12-01

    Observations in the vicinity of summit area of active volcanoes are important not only for understanding physical processes in the volcanic conduit but also for eruption prediction and volcanic hazards mitigation. It is, however, challenging to install observation sensors near active vents because of the danger of sudden eruptions. We need safe and efficient ways of installing sensors near the summit of active volcanoes. We have been developing an volcano observation system based on an unmanned autonomous vehicle (UAV) for risk-free volcano observations. Our UAV is an unmanned autonomous helicopter manufactured by Yamaha-Motor Co., Ltd. The UAV is 3.6m long and weighs 84kg with maximum payload of 10kg. The UAV can aviate autonomously along a previously programmed path within a meter accuracy using real-time kinematics differential GPS equipment. The maximum flight time and distance from the operator are 90 minutes and 5km, respectively. We have developed various types of volcano observation techniques adequate for the UAV, such as aeromagnetic survey, taking infrared and visible images from onboard high-resolution cameras, volcanic ash sampling in the vicinity of active vents. Recently, we have developed an earthquake observation module (EOM), which is exclusively designed for the UAV installation in the vicinity of active volcanic vent. In order to meet the various requirements for UAV installation, the EOM is very compact, light-weight (5-6kg), and is solar-powered. It is equipped with GPS for timing, a communication device using cellular-phone network, and triaxial accelerometers. Our first application of the EOM installation using the UAV is one of the most active volcanoes in Japan, Sakurajima volcano. Since 2006, explosive eruptions have been continuing at the reopened Showa crater at the eastern flank near the summit of Sakurajima. Entering the area within 2 km from the active craters is prohibited, and thus there were no observation station in the vicinity

  7. Cinnabar, arsenian pyrite and thallium-enrichment in active shallow submarine hydrothermal vents at Paleochori Bay, Milos Island, Greece

    NASA Astrophysics Data System (ADS)

    Kati, Marianna; Voudouris, Panagiotis; Valsami-Jones, Eugenia; Magganas, Andreas; Baltatzis, Emmanouil; Kanellopoulos, Christos; Mavrogonatos, Constantinos

    2015-04-01

    We herein report the discovery of active cinnabar-depositing hydrothermal vents in a submarine setting at Paleochori Bay, within the offshore southeastern extension of the Milos Island Geothermal Field, South Aegean Active Volcanic Arc. Active, low temperature (up to 115 °C) hydrothermal venting through volcaniclastic material has led to a varied assemblage of sulfide and alteration mineral phases in an area of approximately 1 km2. Our samples recovered from Paleochori Bay are hydrothermal edifices composed of volcaniclastic detrital material cemented by pyrite, or pure sulfide (mainly massive pyrite) mounts. Besides pyrite and minor marcasite, the hydrothermal minerals include cinnabar, amorphous silica, hydrous ferric oxides, carbonates (aragonite and calcite), alunite-jarosite solid solution and Sr-rich barite. Among others, growth textures, sieve-textured pyrite associated with barite, alunite-jarosite solid solution and hydrous ferric oxides rims colloform-banded pyrite layers. Overgrowths of arsenian pyrite layers (up to 3.2 wt. % As and/or up to 1.1 wt. % Mn) onto As-free pyrite indicate fluctuation in As content of the hydrothermal fluid. Mercury, in the form of cinnabar, occurs in up to 5 μm grains within arsenian pyrite layers, usually forming distinct cinnabar-enriched micro-layers. Hydrothermal Sr-rich barite (barite-celestine solid solution), pseudocubic alunite-jarosite solid solution and Mn- and Sr-enriched carbonates occur in various amounts and closely associated with pyrite and/or hydrous ferric oxides. Thallium-bearing sulfides and/or sulfosalts were not detected during our study; however, hydrous ferric oxides show thallium content of up to 0.5 wt. % Tl. The following scenarios may have played a role in pyrite precipitation at Paleochori: (a) H2S originally dissolved in the deep fluid but separated upon boiling could have reacted with oxygenated seawater under production of sulphuric acid, thus causing leaching and dissolution of primary iron

  8. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  9. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FUEL VENTING AND EXHAUST EMISSION REQUIREMENTS FOR TURBINE ENGINE POWERED AIRPLANES Engine Fuel Venting Emissions (New and In-Use Aircraft Gas Turbine Engines) § 34.11 Standard for fuel venting emissions. (a) No... turbine engine subject to the subpart. This paragraph is directed at the elimination of...

  10. Evidence of sub-vent biosphere: enzymatic activities in 308 °C deep-sea hydrothermal systems at Suiyo seamount, Izu Bonin Arc, Western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Takano, Yoshinori; Edazawa, Yae; Kobayashi, Kensei; Urabe, Tetsuro; Marumo, Katsumi

    2005-01-01

    A high-temperature deep-sea hydrothermal system related to dacitic arc-volcanism was drilled using a tethered, submarine rock-drill system as a part of the Archaean Park Project. The benthic multi-coring system (BMS) employed allowed for direct sampling of microorganisms, rocks and fluids beneath hydrothermal vents. The samples examined in this study were from sites APSK 05 and APSK 07 on the Suiyo Seamount of the Izu-Bonin Arc in the Pacific Ocean. Based on the vertical distribution of samples derived from this vigorous sub-vent environment, a model of deep-sea subterranean chemistry and biology was determined detailing optimal microbial activities. Deep-sea hydrothermal sub-vent core samples of dacitic arc-volcanism obtained at the Suiyo Seamount, Izu-Bonin Arc, Western Pacific Ocean were analyzed for acid and alkaline phosphatase enzymatic activities. Useful biomarkers of acid phosphatase (ACP) and alkaline phosphatase (ALP) enzymatic activities were positively correlated against each other and was greatest at the partial middle core sequences; ACP and ALP activities determined were as high as 5.10 and 6.80 nmol/min/g rock, respectively. Biochemical indicators of ACP and ALP were consistent with the origin of biogenic amino acids occupied in the sub-vent region and microbial cell number in the fluid. The significant enzymatic activities demonstrated in this study provides crucial evidence that sub-vent regions represent part of the previously unknown extreme-environment biosphere, extending the known subterranean habitable spaces of, for example, extremophilic microbes. This boring trial was first example of discharging high temperature hydrothermal activities at the frontal arc volcanoes.

  11. A vented inverted fuel assembly design for an SFR

    SciTech Connect

    Vitillo, F.; Todreas, N. E.; Driscoll, M. J.

    2012-07-01

    The inverted geometry (fuel outside coolant tubes) has been previously investigated at MIT for application in gas-cooled fast reactors and pressurized water-cooled thermal reactors. Venting has also been studied for conventional fuel pins and was employed for those in the Dounreay Fast Reactor. In the present work the inverted fuel approach was adopted because it allows high fuel volume fraction, reduction of the coolant void reactivity, neutron leakage and enrichment, as well as lower pressure drop for the same channel length because grids and wire wraps are no longer necessary. Furthermore most results also apply to venting of conventional fuel pins. Physical and chemical behavior of volatile fission products in sodium was investigated to determine the maximum activity inventory which would eventually be released into the primary sodium. Results of this analysis show that the most troublesome radionuclides in terms of propensity to escape from the venting system are noble gases ({sup 85}Kr and {sup 133}Xe), and cesium ({sup 134}Cs and {sup 137}Cs). A final vented inverted fuel assembly design is proposed which meets all the design goals which have been set. Additionally purification systems were devised to reduce radionuclide activity of the coolant and the cover gas to tolerable levels. It is concluded that vented inverted (or vented conventional pin) fuel is a feasible concept and has sufficiently promising advantages - increasing fuel volume fraction to 50% and core outlet temperature by 20 deg. C, hence incrementing plant thermal efficiency by about 1% - to warrant serious consideration for future SFR designs. (authors)

  12. Shallow Water Hydrothermal Vents in the Gulf of California: Natural Laboratories for Multidisciplinary Research

    NASA Astrophysics Data System (ADS)

    Forrest, M.; Hilton, D. R.; Price, R. E.; Kulongoski, J. T.

    2015-12-01

    Modern and fossil examples of shallow water submarine hydrothermal vents occur throughout the Gulf of California. These sites offer important information about the processes involved in the extensional tectonics that created the Gulf of California and continue to shape the region to this day. Due to their accessibility, shallow water marine hydrothermal vents are far easier to access and study than their deeper analogs, and these settings can provide natural laboratories to study biogeochemical processes. Certain biogeochemical and biomineralizing processes occurring at shallow vents are very similar to those observed around deep-sea hydrothermal vents. In some cases, authigenic carbonates form around shallow vents. However, the hydrothermal precipitates are generally composed of Fe-oxyhydroxides, Mn-oxides, opal, calcite, pyrite and cinnabar, and their textural and morphological characteristics suggest microbial mediation for mineral deposition. Modern shallow-water hydrothermal vents also support complex biotic communities, characterized by the coexistence of chemosynthetic and photosynthetic organisms. These shallow vents are highly productive and provide valuable resources to local fishermen. Extant shallow water hydrothermal activity has been studied in Bahía Concepción, San Felipe, Punta Estrella, El Coloradito, Puertecitos, and around the Islas Encantadas. Discrete streams of gas bubbles are often discharged along with hot liquids at shallow water vents. The vent liquids generally exhibit lower salinities than seawater, and their isotopic compositions indicate that they contain meteoric water mixed with seawater. The composition of the shallow vent gas is primarily made up of CO2, but may also be enriched in N2, H2S, CH4, and other higher hydrocarbons. The geochemistry of these gases can be informative in determining the sources and processes involved in their generation. In particular, 3He/4He ratios may provide valuable information about the origin of

  13. Coupled RNA-SIP and metatranscriptomics of active chemolithoautotrophic communities at a deep-sea hydrothermal vent

    PubMed Central

    Fortunato, Caroline S; Huber, Julie A

    2016-01-01

    The chemolithoautotrophic microbial community of the rocky subseafloor potentially provides a large amount of organic carbon to the deep ocean, yet our understanding of the activity and metabolic complexity of subseafloor organisms remains poorly described. A combination of metagenomic, metatranscriptomic, and RNA stable isotope probing (RNA-SIP) analyses were used to identify the metabolic potential, expression patterns, and active autotrophic bacteria and archaea and their pathways present in low-temperature hydrothermal fluids from Axial Seamount, an active submarine volcano. Metagenomic and metatranscriptomic results showed the presence of genes and transcripts for sulfur, hydrogen, and ammonium oxidation, oxygen respiration, denitrification, and methanogenesis, as well as multiple carbon fixation pathways. In RNA-SIP experiments across a range of temperatures under reducing conditions, the enriched 13C fractions showed differences in taxonomic and functional diversity. At 30 °C and 55 °C, Epsilonproteobacteria were dominant, oxidizing hydrogen and primarily reducing nitrate. Methanogenic archaea were also present at 55 °C, and were the only autotrophs present at 80 °C. Correspondingly, the predominant CO2 fixation pathways changed from the reductive tricarboxylic acid (rTCA) cycle to the reductive acetyl-CoA pathway with increasing temperature. By coupling RNA-SIP with meta-omics, this study demonstrates the presence and activity of distinct chemolithoautotrophic communities across a thermal gradient of a deep-sea hydrothermal vent. PMID:26872039

  14. Coupled RNA-SIP and metatranscriptomics of active chemolithoautotrophic communities at a deep-sea hydrothermal vent.

    PubMed

    Fortunato, Caroline S; Huber, Julie A

    2016-08-01

    The chemolithoautotrophic microbial community of the rocky subseafloor potentially provides a large amount of organic carbon to the deep ocean, yet our understanding of the activity and metabolic complexity of subseafloor organisms remains poorly described. A combination of metagenomic, metatranscriptomic, and RNA stable isotope probing (RNA-SIP) analyses were used to identify the metabolic potential, expression patterns, and active autotrophic bacteria and archaea and their pathways present in low-temperature hydrothermal fluids from Axial Seamount, an active submarine volcano. Metagenomic and metatranscriptomic results showed the presence of genes and transcripts for sulfur, hydrogen, and ammonium oxidation, oxygen respiration, denitrification, and methanogenesis, as well as multiple carbon fixation pathways. In RNA-SIP experiments across a range of temperatures under reducing conditions, the enriched (13)C fractions showed differences in taxonomic and functional diversity. At 30 °C and 55 °C, Epsilonproteobacteria were dominant, oxidizing hydrogen and primarily reducing nitrate. Methanogenic archaea were also present at 55 °C, and were the only autotrophs present at 80 °C. Correspondingly, the predominant CO2 fixation pathways changed from the reductive tricarboxylic acid (rTCA) cycle to the reductive acetyl-CoA pathway with increasing temperature. By coupling RNA-SIP with meta-omics, this study demonstrates the presence and activity of distinct chemolithoautotrophic communities across a thermal gradient of a deep-sea hydrothermal vent.

  15. Hydrothermal activity on the southern Mid-Atlantic Ridge: Tectonically- and volcanically-controlled venting at 4 5°S

    NASA Astrophysics Data System (ADS)

    German, C. R.; Bennett, S. A.; Connelly, D. P.; Evans, A. J.; Murton, B. J.; Parson, L. M.; Prien, R. D.; Ramirez-Llodra, E.; Jakuba, M.; Shank, T. M.; Yoerger, D. R.; Baker, E. T.; Walker, S. L.; Nakamura, K.

    2008-09-01

    We report results from an investigation of the geologic processes controlling hydrothermal activity along the previously-unstudied southern Mid-Atlantic Ridge (3-7°S). Our study employed the NOC (UK) deep-tow sidescan sonar instrument, TOBI, in concert with the WHOI (USA) autonomous underwater vehicle, ABE, to collect information concerning hydrothermal plume distributions in the water column co-registered with geologic investigations of the underlying seafloor. Two areas of high-temperature hydrothermal venting were identified. The first was situated in a non-transform discontinuity (NTD) between two adjacent second-order ridge-segments near 4°02'S, distant from any neovolcanic activity. This geologic setting is very similar to that of the ultramafic-hosted and tectonically-controlled Rainbow vent-site on the northern Mid-Atlantic Ridge. The second site was located at 4°48'S at the axial-summit centre of a second-order ridge-segment. There, high-temperature venting is hosted in an ˜ 18 km 2 area of young lava flows which in some cases are observed to have flowed over and engulfed pre-existing chemosynthetic vent-fauna. In both appearance and extent, these lava flows are directly reminiscent of those emplaced in Winter 2005-06 at the East Pacific Rise, 9°50'N and reference to global seismic catalogues reveals that a swarm of large (M 4.6-5.6) seismic events was centred on the 5°S segment over a ˜ 24 h period in late June 2002, perhaps indicating the precise timing of this volcanic eruptive episode. Temperature measurements at one of the vents found directly adjacent to the fresh lava flows at 5°S MAR (Turtle Pits) have subsequently revealed vent-fluids that are actively phase separating under conditions very close to the Critical Point for seawater, at ˜ 3000 m depth and 407 °C: the hottest vent-fluids yet reported from anywhere along the global ridge crest.

  16. Gas geochemistry of a shallow submarine hydrothermal vent associated with the El Requesón fault zone, Bahía Concepción, Baja California Sur, México

    USGS Publications Warehouse

    Forrest, Matthew J.; Ledesma-Vazquez, Jorge; Ussler, William; Kulongoski, Justin T.; Hilton, David R.; Greene, H. Gary

    2005-01-01

    We investigated hydrothermal gas venting associated with a coastal fault zone along the western margin of Bahía Concepción, B.C.S., México. Copious discharge of geothermal liquid (≈ 90 °C) and gas is occurring in the intertidal and shallow subtidal zones (to a depth of 13 m) through soft sediments and fractures in rocks along a ∼750 m linear trend generally sub-parallel to an onshore fault near Punta Santa Barbara. Hydrothermal activity shows negative correlation with tidal height; temperatures in the area of hydrothermal activity were up to 11.3 °C higher at low tide than at high tide (measured tidal range ≈ 120 cm). Gas samples were collected using SCUBA and analyzed for chemical composition and stable isotope values. The main components of the gas are N2 (≈ 53%; 534 mmol/mol), CO2 (≈ 43%; 435 mmol/mol), and CH4 (≈ 2.2%; 22 mmol/mol). The δ13C values of the CH4 (mean = − 34.3‰), and the ratios of CH4 to C2H6(mean = 89), indicate that the gas is thermogenic in origin. The carbon stable isotopes and the δ15N of the N2 in the gas (mean = 1.7‰) suggest it may be partially derived from the thermal alteration of algal material in immature sedimentary organic matter. The He isotope ratios (3He / 4He = 1.32 RA) indicate a significant mantle component (16.3%) in the gas. Here, we suggest the name El Requesón fault zone for the faults that likely formed as a result of extension in the region during the late Miocene, and are currently serving as conduits for the observed hydrothermal activity.

  17. Observations and coupled models of flow, salinity, and hydrate formation in deepwater Gulf of Mexico vents

    NASA Astrophysics Data System (ADS)

    Smith, A. J.; Flemings, P. B.; Fulton, P. M.

    2010-12-01

    Natural vents in the Gulf of Mexico are actively expelling water, and hydrocarbons. They are ubiquitous across the deepwater and we characterize them in 3 locations: the Auger Basin, the Popeye Basin, and the Ursa Basin. In seismic data, they look like volcanic edifices. Vents are elevated as much as 100 meters relative to the surrounding area and their cores have negative amplitudes that record lower impedance than the overlying water column: this low impedance is interpreted to record the presence of gas. The bottom simulating reflector, which is interpreted to record the boundary between hydrate above and gas and water below, rises toward to the seafloor at the center of the vent. Studies of these vents at Ursa have documented significant temperature anomalies, flow, and high salinities (Paull et al., 2005; Ruppel et al. 2005). We model the coexistence of high salinity fluids, elevated temperatures, and an uplifted bottom simulating reflector with two approaches. First, we assume that high salinity fluids are generated by dissolution of salt bodies at depth and that these hot, saline, fluids are expelled vertically. Second, we model the solidification of gas hydrate during upward flow of gas and water. In this model, free gas combines with water to generate hydrate: salt is excluded, resulting in the generation of a high salinity brine. The two models result in predictable differences of salinity and possibly temperature. A better understanding of the hydrogeological processes at vent zones is important for understanding the fluxes of heat and mass from submarine vents, and it is important for understanding the conditions under which deep sea biological communities exist at these vent locations.

  18. Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico

    NASA Astrophysics Data System (ADS)

    Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard

    2016-08-01

    Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1-2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

  19. Optimized ultrasonic assisted extraction-dispersive liquid-liquid microextraction coupled with gas chromatography for determination of essential oil of Oliveria decumbens Vent.

    PubMed

    Sereshti, Hassan; Izadmanesh, Yahya; Samadi, Soheila

    2011-07-22

    Ultrasonic assisted extraction-dispersive liquid-liquid microextraction (UAE-DLLME) coupled with gas chromatography (GC) was applied for extraction and determination of essential oil constituents of the plant Oliveria decumbens Vent. Scanning electron microscopy (SEM) was used to see the effect of ultrasonic radiation on the extraction efficiency. By comparison with hydrodistillation, UAE-DLLME is fast, low cost, simple, efficient and consuming small amount of plant materials (∼1.0 g). The effects of various parameters such as temperature, ultrasonication time, volume of disperser and extraction solvents were investigated by a full factorial design to identify significant variables and their interactions. The results demonstrated that temperature and ultrasonication time had no considerable effect on the results. In the next step, a central composite design (CCD) was performed to obtain the optimum levels of significant parameters. The obtained optimal conditions were: 0.45 mL for disperser solvent (acetonitrile) and 94.84 μL for extraction solvent (chlorobenzene). The limits of detection (LODs), linear dynamic range and determination coefficients (R(2)) were 0.2-29 ng mL(-1), 1-2100 ng mL(-1) and 0.995-0.998, respectively. The main components of the essential oil were: thymol (47.06%), carvacrol (23.31%), gamma-terpinene (18.94%), p-cymene (8.71%), limonene (0.76%) and myristicin (0.63%).

  20. Hydrothermal vents of Yellowstone Lake, Yellowstone National Park, Wyoming

    SciTech Connect

    Kaplinski, M.A.; Morgan, P. . Geology Dept.)

    1993-04-01

    Hydrothermal vent systems within Yellowstone Lake are located within the Yellowstone caldera in the northeastern and West Thumb sections of the lake. The vent systems lie within areas of extremely high geothermal gradients (< 1,000 C/km) in the lake sediments and occur as clusters of individual vents that expel both hydrothermal fluids and gas. Regions surrounding the vents are colonized by unique, chemotropic biologic communities and suggest that hydrothermal input plays an important role in the nutrient dynamics of the lake's ecosystem. The main concentration of hydrothermal activity occurs in the northeast region of the main lake body in a number of locations including: (1) along the shoreline from the southern edge of Sedge Bay to the inlet of Pelican Creek; (2) the central portion of the partially submerged Mary Bay phreatic explosion crater, within deep (30--50 m) fissures; (3) along the top of a 3 km long, steep-sided ridge that extends from the southern border of Mary Bay, south-southeast into the main lake basin; and (4) east of Stevenson Island along the lower portion of the slope (50--107 m) into the lake basin, within an anastomosing series of north to northwest trending, narrow troughs or fissures. Hydrothermal vents were also located within, and surrounding the West Thumb of Yellowstone Lake, with the main concentration occurring the offshore of the West Thumb and Potts Geyser Basin. Hydrothermal vents in Yellowstone Lake occur along fractures that have penetrated the lake sediments or along the tops of ridges and near shore areas. Underneath the lake, rising hydrothermal fluids encounter a semi-permeable cap of lake sediments. Upwardly convecting hydrothermal fluid flow may be diverted by the impermeable lake sediments along the buried, pre-existing topography. These fluids may continue to rise along topography until fractures are encountered, or the lake sediment cover is thinned sufficiently to allow egress of the fluids.

  1. 40Ar/39Ar dating of tuff vents in the Campi Flegrei caldera (southern Italy): Toward a new chronostratigraphic reconstruction of the Holocene volcanic activity

    USGS Publications Warehouse

    Fedele, L.; Insinga, D.D.; Calvert, A.T.; Morra, V.; Perrotta, A.; Scarpati, C.

    2011-01-01

    The Campi Flegrei hosts numerous monogenetic vents inferred to be younger than the 15 ka Neapolitan Yellow Tuff. Sanidine crystals from the three young Campi Flegrei vents of Fondi di Baia, Bacoli and Nisida were dated using 40Ar/39Ar geochronology. These vents, together with several other young edifices, occur roughly along the inner border of the Campi Flegrei caldera, suggesting that the volcanic conduits are controlled by caldera-bounding faults. Plateau ages of ∼9.6 ka (Fondi di Baia), ∼8.6 ka (Bacoli) and ∼3.9 ka (Nisida) indicate eruptive activity during intervals previously interpreted as quiescent. A critical revision, involving calendar age correction of literature 14C data and available 40Ar/39Ar age data, is presented. A new reference chronostratigraphic framework for Holocene Phlegrean activity, which significantly differs from the previously adopted ones, is proposed. This has important implications for understanding the Campi Flegrei eruptive history and, ultimately, for the evaluation of related volcanic risk and hazard, for which the inferred history of its recent activity is generally taken into account.

  2. Major and trace element distributions around active volcanic vents determined by analyses of grasses: implications for element cycling and bio-monitoring

    NASA Astrophysics Data System (ADS)

    Martin, R. S.; Mather, T. A.; Pyle, D. M.; Day, J. A.; Witt, M. L. I.; Collins, S. J.; Hilton, R. G.

    2010-10-01

    Samples of grass were collected at Masaya Volcano (Nicaragua; Rhynchelytrum repens and Andropogon angustatus) and the Piton de La Fournaise (around the April 2007 eruptive vent, La Réunion; Vetiveria zizanioides) to investigate the controls on major and trace element concentrations in plants around active volcanic vents. Samples were analysed using inductively coupled plasma mass spectrometry for a wide range of elements, and atomic absorption spectroscopy for Hg. At Masaya, As, Cu, Mo, Tl and K concentrations in both grass species showed a simple pattern of variability consistent with exposure to the volcanic plume. Similar variability was found in A. angustatus for Al, Co, Cs, Hg and Mg. At the Piton de La Fournaise, the patterns of variability in V. zizanioides were more complex and related to variable exposures to emissions from both the active vent and lava flow. These results suggest that exposure to volcanic emissions is, for many elements, the main control on compositional variability in vegetation growing on active volcanoes. Thus, vegetation may be an important environmental reservoir for elements emitted by volcanoes and should be considered as part of the global biogeochemical cycles.

  3. 30,000 years of hydrothermal activity at the lost city vent field.

    PubMed

    Früh-Green, Gretchen L; Kelley, Deborah S; Bernasconi, Stefano M; Karson, Jeffrey A; Ludwig, Kristin A; Butterfield, David A; Boschi, Chiara; Proskurowski, Giora

    2003-07-25

    Strontium, carbon, and oxygen isotope data and radiocarbon ages document at least 30,000 years of hydrothermal activity driven by serpentinization reactions at Lost City. Serpentinization beneath this off-axis field is estimated to occur at a minimum rate of 1.2 x 10(-4) cubic kilometers per year. The access of seawater to relatively cool, fresh peridotite, coupled with faulting, volumetric expansion, and mass wasting processes, are crucial to sustain such systems. The amount of heat produced by serpentinization of peridotite massifs, typical of slow and ultraslow spreading environments, has the potential to drive Lost City-type systems for hundreds of thousands, possibly millions, of years.

  4. Fake ballistics and real explosions: field-scale experiments on the ejection and emplacement of volcanic bombs during vent-clearing explosive activity

    NASA Astrophysics Data System (ADS)

    Taddeucci, J.; Valentine, G.; Gaudin, D.; Graettinger, A. H.; Lube, G.; Kueppers, U.; Sonder, I.; White, J. D.; Ross, P.; Bowman, D. C.

    2013-12-01

    Ballistics - bomb-sized pyroclasts that travel from volcanic source to final emplacement position along ballistic trajectories - represent a prime source of volcanic hazard, but their emplacement range, size, and density is useful to inverse model key eruption parameters related to their initial ejection velocity. Models and theory, however, have so far focused on the trajectory of ballistics after leaving the vent, neglecting the complex dynamics of their initial acceleration phase in the vent/conduit. Here, we use field-scale buried explosion experiments to study the ground-to-ground ballistic emplacement of particles through their entire acceleration-deceleration cycle. Twelve blasts were performed at the University at Buffalo Large Scale Experimental Facility with a range of scaled depths (burial depth divided by the cubic root of the energy of the explosive charge) and crater configurations. In all runs, ballistic analogs were placed on the ground surface at variable distance from the vertical projection of the buried charge, resulting in variable ejection angle. The chosen analogs are tennis and ping-pong balls filled with different materials, covering a limited range of sizes and densities. The analogs are tracked in multiple high-speed and high-definition videos, while Particle Image Velocimetry is used to detail ground motion in response to the buried blasts. In addition, after each blast the emplacement position of all analog ballistics was mapped with respect to the blast location. Preliminary results show the acceleration history of ballistics to be quite variable, from very short and relatively simple acceleration coupled with ground motion, to more complex, multi-stage accelerations possibly affected not only by the initial ground motion but also by variable coupling with the gas-particle mixture generated by the blasts. Further analysis of the experimental results is expected to provide new interpretative tools for ballistic deposits and better

  5. Varunaivibrio sulfuroxidans gen. nov., sp. nov., a facultatively chemolithoautotrophic, mesophilic alphaproteobacterium from a shallow-water gas vent at Tor Caldara, Tyrrhenian Sea.

    PubMed

    Patwardhan, Sushmita; Vetriani, Costantino

    2016-09-01

    A mesophilic, facultatively anaerobic, facultatively chemolithoautotrophic bacterium, designated strain TC8T, was isolated from a sulfidic shallow-water marine gas vent located at Tor Caldara, in the Tyrrhenian Sea, Italy. Cells were Gram-stain-negative curved rods with one or more polar flagella. Cells were approximately 1-1.5 µm in length and 0.6 µm in width. Strain TC8T grew between 20 and 35 °C (optimum 30 °C), with between 5 and 45 g NaCl l-1 (optimum 15-20 g l-1) and between pH 4.5 and 8.5 (optimum pH 6.0-7.0). The generation time under optimal conditions was 8 h. Strain TC8T was a facultative chemolithoautotroph also capable of using organic substrates as electron donors and carbon sources. Chemolithoautotrophic growth occurred with sulfur and thiosulfate as the electron donors, CO2 as the carbon source, and nitrate, oxygen (5 %, v/v) and ferric iron as the electron acceptors. Chemoorganoheterotrophic growth occurred with tryptone, peptone, Casamino acids, pyruvate and glycerol as substrates, while chemolithoherotrophic growth occurred with d(+)-glucose, sucrose, yeast extract, acetate, lactate, citrate and l-glutamine. The G+C content of the genomic DNA was 59.9 mol%. Phylogenetic analysis of the 16S rRNA gene sequence of strain TC8T showed that this organism formed a lineage within the family Rhodospirillaceae, which branched separately from the two closest relatives, Magnetovibrio blakemoreiMV1T (91.25 % similarity) and Magnetospira thiophilaMMS-1T (90.13 %). Based on phylogenetic, physiological and chemotaxonomic characteristics, it is proposed that the organism represents a novel species of a new genus within the family Rhodospirillaceae,Varunaivibrio sulfuroxidans gen. nov., sp. nov. The type strain of Varunaivibrio sulfuroxidans is TC8T (=DSM 101688T=JCM 31027T).

  6. Hydrothermal vents and methane seeps: Rethinking the sphere of influence

    USGS Publications Warehouse

    Levin, Lisa A.; Baco, Amy; Bowden, David; Colaco, Ana; Cordes, Erik E.; Cunha, Marina; Demopoulos, Amanda; Gobin, Judith; Grupe, Ben; Le, Jennifer; Metaxas, Anna; Netburn, Amanda; Rouse, Greg; Thurber, Andrew; Tunnicliffe, Verena; Van Dover, Cindy L.; Vanreusel, Ann; Watling, Les

    2016-01-01

    Although initially viewed as oases within a barren deep ocean, hydrothermal vent and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of vent and seep interactions with background systems. We document an expanded footprint beyond the site of local venting or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at vents and seeps are used by “benthic background” fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among vents, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive vents and seeps and background assemblages however, are practically unstudied. The waning of venting or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as well as

  7. Detection of active hydrothermal vent fields in the Pescadero Basin and on the Alarcon Rise using AUV multibeam and CTD data

    NASA Astrophysics Data System (ADS)

    Caress, D. W.; Troni, G.; Clague, D. A.; Paduan, J. B.; Martin, J. F.; Thomas, H. J.; Thompson, D.; Conlin, D.; Martin, E. J.; meneses-Quiroz, E.; Nieves-Cardoso, C.; Angel Santa Rosa del Rio, M.

    2015-12-01

    The MBARI AUV D. Allan B. collected high resolution bathymetry, sidescan, and subbottom profiles along the neovolcanic zone of the Alarcon Rise and across the southern Pescadero Basin during 2012 and 2015 MBARI expeditions to the Gulf of California (GOC). The combination of high resolution multibeam bathymetry and seawater temperature data has proven effective in identifying active high temperature vent fields, as validated by inspection and sampling during ROV dives. The AUV carries a 200 kHz multibeam sonar, 110 kHz chirp sidescan sonar, a 1-6 kHz chirp subbottom profiler, and a conductivity, temperature and depth (CTD) sensor for ~17-hour duration missions. Flying at 5.4 km/hr at 50 m altitude, the processed AUV bathymetry has a 0.1 m vertical precision and a 1 m lateral resolution. Chimneys taller than 1.5 m are sufficiently distinctive to allow provisional identification. The CTD temperature data have a nominal 0.002°C accuracy. Following calculation of potential temperature and correcting for average local variation of potential temperature with depth, anomalies greater than 0.05 °C can be reliably identified using a spike detection filter. MBARI AUV mapping surveys are typically planned using a 150 m survey line spacing, so the CTD data may be collected as much as 75 m away from any vent plume source. Five active high temperature vent fields were discovered in the southern GOC, with the Auka Field in the southern Pescadero Basin, and the Ja Sít, Pericú, Meyibó, and Tzab-ek Fields along the Alarcon Rise. In all five cases, hydrothermal vent chimneys are readily identifiable in the multibeam bathymetry, and temperature anomalies are observed above background variability. Other apparent hydrothermal chimneys were observed in the bathmetry that did not exhibit water temperature anomalies; most of these were visited during ROV dives and confirmed to be inactive sites. The maximum water column anomalies are 0.13°C observed above the Meyibó field and 0.25

  8. Are midwater shrimp trapped in the craters of submarine volcanoes by hydrothermal venting?

    NASA Astrophysics Data System (ADS)

    Wishner, Karen F.; Graff, Jason R.; Martin, Joel W.; Carey, S.; Sigurdsson, H.; Seibel, B. A.

    2005-08-01

    The biology of Kick'em Jenny (KEJ) submarine volcano, part of the Lesser Antilles volcanic arc and located off the coast of Grenada in the Caribbean Sea, was studied during a cruise in 2003. Hydrothermal venting and an associated biological assemblage were discovered in the volcanic crater (˜250 m depth). Warm water with bubbling gas emanated through rock fissures and sediments. Shrimp (some of them swimming) were clustered at vents, while other individuals lay immobile on sediments. The shrimp fauna consisted of 3 mesopelagic species that had no prior record of benthic or vent association. We suggest that these midwater shrimp, from deeper water populations offshore, were trapped within the crater during their downward diel vertical migration. It is unknown whether they then succumbed to the hostile vent environment (immobile individuals) or whether they are potentially opportunistic vent residents (active individuals). Given the abundance of submarine arc volcanoes worldwide, this phenomenon suggests that volcanic arcs could be important interaction sites between oceanic midwater and vent communities.

  9. Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge.

    PubMed

    Pedersen, Rolf B; Rapp, Hans Tore; Thorseth, Ingunn H; Lilley, Marvin D; Barriga, Fernando J A S; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L; Jorgensen, Steffen L

    2010-11-23

    The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific.

  10. Discovery of a black smoker vent field and vent fauna at the Arctic Mid-Ocean Ridge

    PubMed Central

    Pedersen, Rolf B.; Rapp, Hans Tore; Thorseth, Ingunn H.; Lilley, Marvin D.; Barriga, Fernando J. A. S.; Baumberger, Tamara; Flesland, Kristin; Fonseca, Rita; Früh-Green, Gretchen L.; Jorgensen, Steffen L.

    2010-01-01

    The Arctic Mid-Ocean Ridge (AMOR) represents one of the most slow-spreading ridge systems on Earth. Previous attempts to locate hydrothermal vent fields and unravel the nature of venting, as well as the provenance of vent fauna at this northern and insular termination of the global ridge system, have been unsuccessful. Here, we report the first discovery of a black smoker vent field at the AMOR. The field is located on the crest of an axial volcanic ridge (AVR) and is associated with an unusually large hydrothermal deposit, which documents that extensive venting and long-lived hydrothermal systems exist at ultraslow-spreading ridges, despite their strongly reduced volcanic activity. The vent field hosts a distinct vent fauna that differs from the fauna to the south along the Mid-Atlantic Ridge. The novel vent fauna seems to have developed by local specialization and by migration of fauna from cold seeps and the Pacific. PMID:21119639

  11. External Tank GH2 Vent Arm

    NASA Technical Reports Server (NTRS)

    Reichle, G. E.; Glassburn, C. W.

    1985-01-01

    Because the venting of free hydrogen gas to the atmosphere presents an extremely hazardous situation, it was necessary to devise a means for safe, controlled venting of the shuttle external tank gaseous hydrogen during and after liquid hydrogen tank loading. Several design concepts that were considered initially were discarded as unfeasible because of vehicle weight restrictions, high cost, and because the proposed structure was itself deemed a hazard due to the vehicle's nonvertical launch trajectory. These design concepts are discussed. A design employing a support structure/access arm attached to the fixed service structure was finally selected. The various design problems resolved included vent arm disconnect/drop interference, minimizing refurbishment due to launch damage, disconnect reliability, vehicle movement tracking, minimizing vent line pressure drop, and the presence of other vehicle services at the same centralized supply area. Six launches have proven the system to be reliable, efficient, and of nearly zero refurbishment cost.

  12. Dynamics of an open basaltic magma system: The 2008 activity of the Halema‘uma‘u Overlook vent, Kīlauea Caldera

    USGS Publications Warehouse

    Eychenne, Julia; Houghton, Bruce; Swanson, Don; Carey, Rebecca; Swavely, Lauren

    2015-01-01

    On March 19, 2008 a small explosive event accompanied the opening of a 35-m-wide vent (Overlook vent) on the southeast wall of Halema‘uma‘u Crater in Kīlauea Caldera, initiating an eruptive period that extends to the time of writing. The peak of activity, in 2008, consisted of alternating background open-system outgassing and spattering punctuated by sudden, short-lived weak explosions, triggered by collapses of the walls of the vent and conduit. Near-daily sampling of the tephra from this open system, along with exceptionally detailed observations, allow us to study the dynamics of the activity during two eruptive sequences in late 2008. Each sequence includes background activity preceding and following one or more explosions in September and October 2008 respectively. Componentry analyses were performed for daily samples to characterise the diversity of the ejecta. Nine categories of pyroclasts were identified in all the samples, including wall-rock fragments. The six categories of juvenile clasts can be grouped in three classes based on vesicularity: (1) poorly, (2) uniformly highly to extremely, and (3) heterogeneously highly vesicular. The wall-rock and juvenile clasts show dissimilar grainsize distributions, reflecting different fragmentation mechanisms. The wall-rock particles formed by failure of the vent and conduit walls above the magma free surface and were then passively entrained in the eruptive plume. The juvenile componentry reveals consistent contrasts in degassing and fragmentation processes before, during and after the explosive events. We infer a crude ‘layering’ developed in the shallow melt, in terms of both rheology and bubble and volatile contents, beneath a convecting free surface during background activity. A tens-of-centimetres thick viscoelastic surface layer was effectively outgassed and relatively cool, while at depths of less than 100 m, the melt remained slightly supersaturated in volatiles and actively vesiculating

  13. Preliminary results on the reproduction of a deep-sea snailfish Careproctus rhodomelas around the active hydrothermal vent on the Hatoma Knoll, Okinawa, Japan.

    PubMed

    Takemura, A; Tamotsu, S; Miwa, T; Yamamoto, H

    2010-11-01

    Deep-sea snailfish Careproctus rhodomelas were collected from an active hydrothermal vent using a remotely operated vehicle (R.O.V. Hyper-dolphin) and a pressurized device (Deep-Aquarium). Careproctus rhodomelas exhibited a cystovarian-type ovary containing a small number of developing oocytes at different stages, suggesting that the fish is a batch-spawner that spawns large eggs (c. 6·0 mm) several times within its life span. In vitro culture of the oocytes in the presence of human chorionic gonadotropin showed that oestradiol-17β production fluctuated with oocyte development, suggesting that the oocytes were at the vitellogenic stage.

  14. Neutron-induced prompt gamma activation analysis (PGAA) of metalsand non-metals in ocean floor geothermal vent-generated samples

    SciTech Connect

    Perry, D.L.; Firestone, R.B.; Molnar, G.L.; Revay, Zs.; Kasztovszky, Zs.; Gatti, R.C.; Wilde, P.

    2002-12-05

    Neutron-induced prompt gamma activation analysis (PGAA) hasbeen used to analyze ocean floor geothermal vent-generated samples thatare composed of mixed metal sulfides, silicates, and aluminosilicates.The modern application of the PGAA technique is discussed, and elementalanalytical results are given for 25 elements observed in the samples. Theelemental analysis of the samples is consistent with the expectedmineralogical compositions, and very consistent results are obtained forcomparable samples. Special sensitivity to trace quantities of hydrogen,boron, cadmium, dysprosium, gadolinium, and samarium isdiscussed.

  15. Battery Vent Mechanism And Method

    DOEpatents

    Ching, Larry K. W.

    2000-02-15

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  16. Battery venting system and method

    DOEpatents

    Casale, Thomas J.; Ching, Larry K. W.; Baer, Jose T.; Swan, David H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve.

  17. Battery venting system and method

    DOEpatents

    Casale, T.J.; Ching, L.K.W.; Baer, J.T.; Swan, D.H.

    1999-01-05

    Disclosed herein is a venting mechanism for a battery. The venting mechanism includes a battery vent structure which is located on the battery cover and may be integrally formed therewith. The venting mechanism includes an opening extending through the battery cover such that the opening communicates with a plurality of battery cells located within the battery case. The venting mechanism also includes a vent manifold which attaches to the battery vent structure. The vent manifold includes a first opening which communicates with the battery vent structure opening and second and third openings which allow the vent manifold to be connected to two separate conduits. In this manner, a plurality of batteries may be interconnected for venting purposes, thus eliminating the need to provide separate vent lines for each battery. The vent manifold may be attached to the battery vent structure by a spin-welding technique. To facilitate this technique, the vent manifold may be provided with a flange portion which fits into a corresponding groove portion on the battery vent structure. The vent manifold includes an internal chamber which is large enough to completely house a conventional battery flame arrester and overpressure safety valve. In this manner, the vent manifold, when installed, lessens the likelihood of tampering with the flame arrester and safety valve. 8 figs.

  18. 40 CFR 65.115 - Standards: Closed vent systems and control devices; or emissions routed to a fuel gas system or...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... no later than the implementation date specified in § 65.1(f). (b) Compliance standard. (1) Owners or... shall design and operate the closed vent systems and nonflare control devices to reduce emissions of... to comply with the provisions of this subpart shall design and operate the flare as specified in §...

  19. Methanocaldococcus bathoardescens sp. nov., a hyperthermophilic methanogen isolated from a volcanically active deep-sea hydrothermal vent.

    PubMed

    Stewart, Lucy C; Jung, Jong-Hyun; Kim, You-Tae; Kwon, Soon-Wo; Park, Cheon-Seok; Holden, James F

    2015-04-01

    A hyperthermophilic methanogen, strain JH146(T), was isolated from 26 °C hydrothermal vent fluid emanating from a crack in basaltic rock at Marker 113 vent, Axial Seamount in the northeastern Pacific Ocean. It was identified as an obligate anaerobe that uses only H2 and CO2 for growth. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain is more than 97% similar to other species of the genus Methanocaldococcus . Therefore, overall genome relatedness index analyses were performed to establish that strain JH146(T) represents a novel species. For each analysis, strain JH146(T) was most similar to Methanocaldococcus sp. FS406-22, which can fix N2 and also comes from Marker 113 vent. However, strain JH146(T) differs from strain FS406-22 in that it cannot fix N2. The average nucleotide identity score for strain JH146(T) was 87%, the genome-to-genome direct comparison score was 33-55% and the species identification score was 93%. For each analysis, strain JH146(T) was below the species delineation cut-off. Full-genome gene synteny analysis showed that strain JH146(T) and strain FS406-22 have 97% genome synteny, but strain JH146(T) was missing the operons necessary for N2 fixation and assimilatory nitrate reduction that are present in strain FS406-22. Based on its whole genome sequence, strain JH146(T) is suggested to represent a novel species of the genus Methanocaldococcus for which the name Methanocaldococcus bathoardescens is proposed. The type strain is JH146(T) ( = DSM 27223(T) = KACC 18232(T)).

  20. Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse hydrothermal vents of the Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Bourbonnais, A.; Juniper, S. K.; Butterfield, D. A.; Devol, A. H.; Kuypers, M. M. M.; Lavik, G.; Hallam, S. J.; Wenk, C. B.; Chang, B. X.; Murdock, S. A.; Lehmann, M. F.

    2012-04-01

    Little is known about nitrogen (N) transformations in general, and the elimination of N in particular, at diffuse vents where anoxic hydrothermal fluids have mixed with oxygenated crustal seawater prior to discharge. Oceanic N sinks that remove bio-available N ultimately affect chemosynthetic primary productivity in these ecosystems. Using 15N paired isotope techniques, we determined potential rates of fixed N-loss pathways (denitrification, anammox) and dissimilative nitrate reduction to ammonium (DNRA) in sulfidic hydrothermal vent fluids discharging from the subsurface at several sites at Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge. We also measured physico-chemical parameters (i.e. temperature, pH, nutrients, H2S and N2O concentrations) as well as the biodiversity and abundance of chemolithotrophic nitrate-reducing, sulfur-oxidizing γ-proteobacteria (SUP05 cluster) using sequence analysis of amplified small subunit ribosomal RNA (16S rRNA) genes in combination with taxon-specific quantitative polymerase chain reaction (qPCR) assays. Denitrification was the dominant N-loss pathway in the subsurface biosphere of the Juan de Fuca Ridge, with rates of up to ~1000 nmol N l-1 day-1. In comparison, anammox rates were always <5 nmol N l-1 day-1 and below the detection limit at most of the sites. DNRA rates were up to 152 nmol N l-1 day-1. These results suggest that bacterial denitrification out-competes anammox in sulfidic hydrothermal vent waters. Taxon-specific qPCR revealed that γ-proteobacteria of the SUP05 cluster sometimes dominated the microbial community (SUP05/total bacteria up to 38%). Significant correlation existed between fixed N-loss (i.e., denitrification, anammox) rates and in-situ nitrate and dissolved inorganic nitrogen (DIN) deficits in the fluids, indicating that DIN availability may ultimately regulate N-loss in the subsurface. Based on our rate measurements, and on published data on hydrothermal fluid fluxes and residence

  1. Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse hydrothermal vents of the Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Bourbonnais, A.; Juniper, S. K.; Butterfield, D. A.; Devol, A. H.; Kuypers, M. M. M.; Lavik, G.; Hallam, S. J.; Wenk, C. B.; Chang, B. X.; Murdock, S. A.; Lehmann, M. F.

    2012-11-01

    Little is known about fixed nitrogen (N) transformation and elimination at diffuse hydrothermal vents where anoxic fluids are mixed with oxygenated crustal seawater prior to discharge. Oceanic N sinks that remove bio-available N ultimately affect chemosynthetic primary productivity in these ecosystems. Using 15N paired isotope techniques, we determined potential rates of fixed N loss pathways (denitrification, anammox) and dissimilatory nitrate reduction to ammonium (DNRA) in sulfidic hydrothermal vent fluids discharging from the subsurface at several sites at Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge. We also measured physico-chemical parameters (i.e., temperature, pH, nutrients, H2S and N2O concentrations) as well as the biodiversity and abundance of chemolithoautotrophic nitrate-reducing, sulfur-oxidizing γ-proteobacteria (SUP05 cluster) using sequence analysis of amplified small subunit ribosomal RNA (16S rRNA) genes in combination with taxon-specific quantitative polymerase chain reaction (qPCR) assays. Denitrification was the dominant N loss pathway in the subsurface biosphere of the Juan de Fuca Ridge, with rates of up to ~1000 nmol N l-1 day-1. In comparison, anammox rates were always < 5 nmol N l-1 day-1 and below the detection limit at most of the sites. DNRA rates were up to ~150 nmol N l-1 day-1. These results suggest that bacterial denitrification out-competes anammox in sulfidic hydrothermal vent waters. Taxon-specific qPCR revealed that γ-proteobacteria of the SUP05 cluster sometimes dominated the microbial community (SUP05/total bacteria up to 38%). Significant correlations were found between fixed N loss (i.e., denitrification, anammox) rates and in situ nitrate and dissolved inorganic nitrogen (DIN) deficits in the fluids, indicating that DIN availability may ultimately regulate N loss in the subsurface. Based on our rate measurements, and on published data on hydrothermal fluid fluxes and residence times, we estimated

  2. Implementation and evaluation of an inexpensive low-power low-noise infrasound sensor and its use in a dense sensor network around an active volcanic vent

    NASA Astrophysics Data System (ADS)

    Marcillo, O. E.; Johnson, J. B.; Hart, D. M.

    2011-12-01

    The development and evaluation of a low-cost infrasound sensor, the infraNMT, and its use as part of a dense (45-element) sensor network around an active volcanic vent, are described. This sensor is based on a commercial micro-machined piezo-resistive differential pressure transducer that uses a mechanical high-pass filter to reject low-frequency out-band energy. The sensor features low noise, 2.02 mPa rms (0.5-2 Hz), 5.47 mPa RMS (0.1-20 Hz), or 5.62 mPa rms (0.05-20 Hz), flat response between 0.01 Hz to at least 40 Hz, inband sensitivity of 45.13 +/-0.23 μV/Pa, and nominal linear range of -124.5 to +124.5 Pa. The sensor consumes a minimum of 24 mW, and operates with voltages above 8V while drawing 3mA of current. The infraNMT specifications described above were independently verified using the infrasound test chamber at the Sandia National Laboratories' Facility for Acceptance, Calibration, and Testing (SNL-FACT) and following procedures for comparison calibration against traceable reference stands in voltage and pressure. Due to the intended broad frequency response of this sensor the testing chamber was configured in a double reference sensor scheme. A well-characterized MB2000 micro-barometer (with a flat amplitude response between 0.01 and 8 Hz) and microphone (with a flat amplitude response above 8Hz) were used simultaneously in this double reference test configuration. The characteristics of the infraNMT, including small size, low power consumption, high dynamic range, and low cost, favor its use in array or network configurations for near source and/or higher noise environments. This sensor has been used for infrasound array studies associated with various sources, including volcanic and chemical explosions, glacier earthquakes, and thunder. In this study we report on the Summer 2010 deployment of a network of 45 infraNMT sensors at Kilauea volcano to study the infrasound generated by degassing of the active Halema'uma'u vent. For this experiment, the

  3. Variable explosive energy partitioning during open vent activity at Fuego volcano, Guatemala 2007-2009: constraining explosion source processes and implications for monitoring

    NASA Astrophysics Data System (ADS)

    Lyons, J. J.; Waite, G. P.; Rose, W. I.

    2009-12-01

    Fuego volcano, Guatemala is a 3800 m-high stratovolcano that has displayed open vent behavior since 1999, and has had several periods of historic open vent activity as well as more than 60 historical subplinian eruptions. Two years of continuous visual observations (2005-2007) and six months of seismic and acoustic data (2007) showed a repeating cycle of eruptive behavior that consisted of 1) passive lava effusion and minor strombolian explosions, 2) paroxysmal eruptions lasting 24-48 hours, and 3) degassing explosions with no associated effusion. The strombolian explosions that occurred during periods of passive lava effusion are characteristically distinct from degassing explosions. In this study, we quantify the ratio of radiated infrasound to seismic energy for each class of eruption during study periods in 2007, 2008 and 2009 to distinguish between potential models for the events. More than 25,000 people inhabit the high hazard zone around Fuego volcano, and the potential to track activity using explosive energy partitioning has monitoring and hazard implications. Strombolian explosions during passive effusion typically occur several times per hour, eject incandescent bombs, and produce ash-poor eruptive clouds. Degassing explosions characteristically occur once per hour, produce ash-rich eruptive clouds, and eject primarily lithic blocks. Two general types of degassing explosions are observed, 1) impulsive events with high excess pressure and 2) emergent, lower pressure transients in the acoustic traces without clear ground-coupled airwaves in the seismic data. On the other hand, strombolian explosions are nearly always impulsive in the acoustic traces but the seismic expressions of these events are variable. During the 2007 experiment, degassing explosions recorded at ~7 km from the vent show stable seismic-to-acoustic amplitude ratios ranging over less than an order of magnitude, while the energy partitioning during strombolian explosions varies widely with

  4. 40 CFR 65.143 - Closed vent systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Closed vent systems. 65.143 Section 65.143 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or...

  5. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Design of Pipeline Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top...

  6. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1989-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer-generated graphical representation. The fields obtained with a radially scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters of 3/16 inch to 1-1/2 inches I.D. (4.76 mm to 38.1 mm). The N(2) mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  7. Flow fields of low pressure vent exhausts

    NASA Technical Reports Server (NTRS)

    Scialdone, John J.

    1990-01-01

    The flow field produced by low pressure gas vents are described based on experimental data obtained from tests in a large vacuum chamber. The gas density, pressure, and flux at any location in the flow field are calculated based on the vent plume description and the knowledge of the flow rate and velocity of the venting gas. The same parameters and the column densities along a specified line of sight traversing the plume are also obtained and shown by a computer generated graphical representation. The fields obtained with a radically scanning Pitot probe within the exhausting gas are described by a power of the cosine function, the mass rate, and the distance from the exit port. The field measurements were made for gas at pressures ranging from 2 to 50 torr venting from pipe fittings with diameters to 3/16 to 1-1/2 inches I.D. (4.76 to 38.1 mm). The N2 mass flow rates ranged from 2E-4 to 3.7E-1 g/s.

  8. Electrochemical cell having improved pressure vent

    DOEpatents

    Dean, Kevin; Holland, Arthur; Fillmore, Donn

    1993-01-01

    The electrochemical cell of the instant invention includes a case having a gas outlet, one or more positive electrodes positioned within the case, one or more negative electrodes positioned within the case electrode separators positioned between the positive and negative electrodes, electrolyte positioned within the case, and a pressure vent for releasing internal pressure occurring in the case to the surrounding atmosphere. The pressure vent is affixed to the case covering the gas outlet, the pressure vent includes a vent housing having a hollow interior area in gaseous communication with the surrounding atmosphere and the interior of the case via the gas outlet, a pressure release piston positioned within the hollow interior area, the pressure release piston sized to surround the gas outlet and having a seal groove configured to encapsulate all but one surface of a seal mounted within the seal groove, leaving the non-encapsulated surface of the seal exposed, and a compression spring positioned to urge the pressure release piston to compress the seal in the seal groove and block the gas outlet in the case.

  9. Geochemical constraints on the diversity and activity of H2 -oxidizing microorganisms in diffuse hydrothermal fluids from a basalt- and an ultramafic-hosted vent.

    PubMed

    Perner, Mirjam; Petersen, Jillian M; Zielinski, Frank; Gennerich, Hans-Hermann; Seifert, Richard

    2010-10-01

    Mixing processes of reduced hydrothermal fluids with oxygenated seawater and fluid-rock reactions contribute to the chemical signatures of diffuse venting and likely determine the geochemical constraints on microbial life. We examined the influence of fluid chemistry on microbial diversity and activity by sampling diffuse fluids emanating through mussel beds at two contrasting hydrothermal vents. The H(2) concentration was very low at the basalt-hosted Clueless site, and mixing models suggest O(2) availability throughout much of the habitat. In contrast, effluents from the ultramafic-hosted Quest site were considerably enriched in H(2) , while O(2) is likely limited to the mussel layer. Only two different hydrogenase genes were identified in clone libraries from the H(2) -poor Clueless fluids, but these fluids exhibited the highest H(2) uptake rates in H(2) -spiked incubations (oxic conditions, at 18 °C). In contrast, a phylogenetically diverse H(2) -oxidizing potential was associated with distinct thermal conditions in the H(2) -rich Quest fluids, but under oxic conditions, H(2) uptake rates were extremely low. Significant stimulation of CO(2) fixation rates by H(2) addition was solely illustrated in Quest incubations (P-value <0.02), but only in conjunction with anoxic conditions (at 18 °C). We conclude that the factors contributing toward differences in the diversity and activity of H(2) oxidizers at these sites include H(2) and O(2) availability.

  10. Effects of Hemagglutination Activity in the Serum of a Deep-Sea Vent Endemic Crab, Shinkaia Crosnieri, on Non-Symbiotic and Symbiotic Bacteria.

    PubMed

    Fujiyoshi, So; Tateno, Hiroaki; Watsuji, Tomoo; Yamaguchi, Hideyuki; Fukushima, Daisuke; Mino, Sayaka; Sugimura, Makoto; Sawabe, Tomoo; Takai, Ken; Sawayama, Shigeki; Nakagawa, Satoshi

    2015-01-01

    In deep-sea hydrothermal environments, most invertebrates associate with dense populations of symbiotic microorganisms in order to obtain nutrition. The molecular interactions between deep-sea animals and environmental microbes, including their symbionts, have not yet been elucidated in detail. Hemagglutinins/lectins, which are carbohydrate-binding proteins, have recently been reported to play important roles in a wide array of biological processes, including the recognition and control of non-self materials. We herein assessed hemagglutination activity in the serum of a deep-sea vent endemic crab, Shinkaia crosnieri, which harbors chemosynthetic epibionts on its plumose setae. Horse and rabbit erythrocytes were agglutinated using this serum (opt. pH 7.5 and opt. temperature 15°C). Agglutinating activity was inhibited by eight kinds of sugars and several divalent cations, did not require any divalent metal ions, and remained detectable even after heating the serum at 100°C for 30 min. By using fluorescently labeled serum, we demonstrated that deep-sea crab serum components bound to the epibionts even in the presence of sugars. This study represents the first immunological assessment of a deep-sea vent endemic crab and demonstrated the possibility of a non-lectin-mediated symbiont-host interaction.

  11. Effects of Hemagglutination Activity in the Serum of a Deep-Sea Vent Endemic Crab, Shinkaia Crosnieri, on Non-Symbiotic and Symbiotic Bacteria

    PubMed Central

    Fujiyoshi, So; Tateno, Hiroaki; Watsuji, Tomoo; Yamaguchi, Hideyuki; Fukushima, Daisuke; Mino, Sayaka; Sugimura, Makoto; Sawabe, Tomoo; Takai, Ken; Sawayama, Shigeki; Nakagawa, Satoshi

    2015-01-01

    In deep-sea hydrothermal environments, most invertebrates associate with dense populations of symbiotic microorganisms in order to obtain nutrition. The molecular interactions between deep-sea animals and environmental microbes, including their symbionts, have not yet been elucidated in detail. Hemagglutinins/lectins, which are carbohydrate-binding proteins, have recently been reported to play important roles in a wide array of biological processes, including the recognition and control of non-self materials. We herein assessed hemagglutination activity in the serum of a deep-sea vent endemic crab, Shinkaia crosnieri, which harbors chemosynthetic epibionts on its plumose setae. Horse and rabbit erythrocytes were agglutinated using this serum (opt. pH 7.5 and opt. temperature 15°C). Agglutinating activity was inhibited by eight kinds of sugars and several divalent cations, did not require any divalent metal ions, and remained detectable even after heating the serum at 100°C for 30 min. By using fluorescently labeled serum, we demonstrated that deep-sea crab serum components bound to the epibionts even in the presence of sugars. This study represents the first immunological assessment of a deep-sea vent endemic crab and demonstrated the possibility of a non-lectin-mediated symbiont-host interaction. PMID:26212518

  12. Linking geology, fluid chemistry, and microbial activity of basalt- and ultramafic-hosted deep-sea hydrothermal vent environments.

    PubMed

    Perner, M; Hansen, M; Seifert, R; Strauss, H; Koschinsky, A; Petersen, S

    2013-07-01

    Hydrothermal fluids passing through basaltic rocks along mid-ocean ridges are known to be enriched in sulfide, while those circulating through ultramafic mantle rocks are typically elevated in hydrogen. Therefore, it has been estimated that the maximum energy in basalt-hosted systems is available through sulfide oxidation and in ultramafic-hosted systems through hydrogen oxidation. Furthermore, thermodynamic models suggest that the greatest biomass potential arises from sulfide oxidation in basalt-hosted and from hydrogen oxidation in ultramafic-hosted systems. We tested these predictions by measuring biological sulfide and hydrogen removal and subsequent autotrophic CO2 fixation in chemically distinct hydrothermal fluids from basalt-hosted and ultramafic-hosted vents. We found a large potential of microbial hydrogen oxidation in naturally hydrogen-rich (ultramafic-hosted) but also in naturally hydrogen-poor (basalt-hosted) hydrothermal fluids. Moreover, hydrogen oxidation-based primary production proved to be highly attractive under our incubation conditions regardless whether hydrothermal fluids from ultramafic-hosted or basalt-hosted sites were used. Site-specific hydrogen and sulfide availability alone did not appear to determine whether hydrogen or sulfide oxidation provides the energy for primary production by the free-living microbes in the tested hydrothermal fluids. This suggests that more complex features (e.g., a combination of oxygen, temperature, biological interactions) may play a role for determining which energy source is preferably used in chemically distinct hydrothermal vent biotopes.

  13. Cryogenic fluid management technologies for space transportation. Zero G thermodynamic vent system

    NASA Technical Reports Server (NTRS)

    1994-01-01

    Long term storage of subcritical cryogens in space must address the problem of thermal stratification in the storage tanks, liquid acquisition devices, and associated feed systems. Due to the absence of gravity induced body forces, thermal stratification in zero-g is more severe than commonly experienced in a one-g environment. If left uncontrolled, the thermal gradients result in excessive tank pressure rise and the formation of undesirable liquid/vapor mixtures within the liquid bulk, liquid acquisition system, and propellant transfer lines. Since external heat leakage cannot be eliminated, a means of minimizing the thermal stratification in the ullage gas, liquid, and feed system is required. A subsystem which minimizes the thermal stratification and rejects the environmental heat leakage in an efficient manner is therefore needed for zero-g subcritical cryogenic systems. In ground based storage systems the ullage gas location is always known (top of the tank) and therefore direct venting of gases as a means of heat rejection is easily accomplished. In contrast, because the ullage location in a zero-g environment is not easily predictable, heat rejection through direct gaseous venting is difficult in space (requires liquid settling, or surface tension devices). A means of indirect venting through the use of a thermodynamic vent system (TVS) is therefore required. A thermodynamic vent system allows indirect venting of vapor through heat exchange between the vented fluid and the stored fluid. The objective is to ensure that only gas and not liquid is vented, in order to minimize the propellant losses. Consequently, the design of a TVS is a critical enabling technology for future applications such as solar thermal and electric propulsion, single-stage-to-orbit vertical landers and upper stages, and any space based operations involving subcritical cryogenics. To bridge this technology gap NASA MSFC initiated an effort to build and verify through ground tests a zero

  14. Response of key stress-related genes of the seagrass Posidonia oceanica in the vicinity of submarine volcanic vents

    NASA Astrophysics Data System (ADS)

    Lauritano, C.; Ruocco, M.; Dattolo, E.; Buia, M. C.; Silva, J.; Santos, R.; Olivé, I.; Costa, M. M.; Procaccini, G.

    2015-03-01

    Submarine volcanic vents are being used as natural laboratories to assess the effects of CO2 on marine organisms and communities, as this gas is the main component of emissions. Seagrasses should positively react to increased dissolved carbon, but in vicinity of volcanic vents there may be toxic substances, that can have indirect effects on seagrasses. Here we analysed the expression of 35 stress-related genes in the Mediterranean keystone seagrass species P. oceanica in the vicinity of submerged volcanic vents located in the Islands of Ischia and Panarea, Italy, and compared them with those from control sites away from the influence of vents. Reverse Transcription-Quantitative Polymerase Chain Reaction (RT-qPCR) was used to characterize the expression levels of genes. Fifty one per cent of genes analysed showed significant expression changes. Metal detoxification genes were mostly down-regulated in relation to controls both in Ischia and Panarea locations, indicating that P. oceanica does not increase the synthesis of heavy metal detoxification proteins in response to the environmental conditions present at the two vents. The expression levels of genes involved in free radical detoxification indicate that, in contrast with Ischia, P. oceanica at the Panarea vent face stressors that result in the production of reactive oxygen species triggering antioxidant responses. In addition, heat shock proteins were also activated at Panarea and not at Ischia. Overall, our study reveals that P. oceanica is generally under higher stress in the vicinity of the vents at Panarea than at Ischia, possibly resulting from environmental and evolutionary differences existing between the two volcanic sites. This is the first study analysing gene responses in marine plants living near natural CO2 vents and our results call for a careful consideration of factors, other than CO2 and acidification, that can cause stress to seagrasses and other organisms near volcanic vents.

  15. Ecology of deep-sea hydrothermal vent communities: A review

    SciTech Connect

    Lutz, R.A.; Kennish, M.J. )

    1993-08-01

    The present article reviews studies of the past 15 years of active and inactive hydrothermal vents. The focus of the discussion is on the ecology of the biological communities inhabiting hydrothermal vents. These communities exhibit high densities and biomass, low species diversity, rapid growth rates, and high metabolic rates. The authors attempt to relate the biology of hydrothermal vent systems to geology. Future directions for hydrothermal vent research are suggested. Since many vent populations are dependent on hydrothermal fluids and are consequently unstable, both short- and long-term aspects of the ecology of the vent organisms and the influence of chemical and geological factors on the biology of vent systems need to be established. 200 refs., 28 figs.

  16. ANALYSIS OF VENTING OF A RESIN SLURRY

    SciTech Connect

    Laurinat, J.; Hensel, S.

    2012-03-27

    A resin slurry venting analysis was conducted to address safety issues associated with overpressurization of ion exchange columns used in the Purex process at the Savannah River Site (SRS). If flow to these columns were inadvertently interrupted, an exothermic runaway reaction could occur between the ion exchange resin and the nitric acid used in the feed stream. The nitric acid-resin reaction generates significant quantities of noncondensable gases, which would pressurize the column. To prevent the column from rupturing during such events, rupture disks are installed on the column vent lines. The venting analysis models accelerating rate calorimeter (ARC) tests and data from tests that were performed in a vented test vessel with a rupture disk. The tests showed that the pressure inside the test vessel continued to increase after the rupture disk opened, though at a slower rate than prior to the rupture. Calculated maximum discharge rates for the resin venting tests exceeded the measured rates of gas generation, so the vent size was sufficient to relieve the pressure in the test vessel if the vent flow rate was constant. The increase in the vessel pressure is modeled as a transient phenomenon associated with expansion of the resin slurry/gas mixture upon rupture of the disk. It is postulated that the maximum pressure at the end of this expansion is limited by energy minimization to approximately 1.5 times the rupture disk burst pressure. The magnitude of this pressure increase is consistent with the measured pressure transients. The results of this analysis demonstrate the need to allow for a margin between the design pressure and the rupture disk burst pressure in similar applications.

  17. Passive soil venting at the Chemical Waste Landfill Site at Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Phelan, J.M.; Reavis, B.; Cheng, W.C.

    1995-05-01

    Passive Soil Vapor Extraction was tested at the Chemical Waste Landfill (CWL) site at Sandia National Laboratories, New Mexico (SNLIW). Data collected included ambient pressures, differential pressures between soil gas and ambient air, gas flow rates into and out of the soil and concentrations of volatile organic compounds (VOCS) in vented soil gas. From the differential pressure and flow rate data, estimates of permeability were arrived at and compared with estimates from other studies. Flow, differential pressure, and ambient pressure data were collected for nearly 30 days. VOC data were collected for two six-hour periods during this time. Total VOC emissions were calculated and found to be under the limit set by the Resource Conservation and Recovery Act (RCRA). Although a complete process evaluation is not possible with the data gathered, some of the necessary information for designing a passive venting process was determined and the important parameters for designing the process were indicated. More study is required to evaluate long-term VOC removal using passive venting and to establish total remediation costs when passive venting is used as a polishing process following active soil vapor extraction.

  18. 40 CFR 87.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... venting emissions shall be discharged into the atmosphere from any new or in-use aircraft gas turbine... the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and does...

  19. 40 CFR 87.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... fuel venting emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...

  20. 14 CFR 34.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... fuel venting emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...

  1. 40 CFR 87.11 - Standard for fuel venting emissions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... fuel venting emissions shall be discharged into the atmosphere from any new or in-use aircraft gas... discharge to the atmosphere of fuel drained from fuel nozzle manifolds after engines are shut down and...

  2. Sulfur isotope systematics of microbial mats in shallow-sea hydrothermal vents, Milos Island, Greece

    NASA Astrophysics Data System (ADS)

    Gilhooly, W. P.; Fike, D. A.; Amend, J. P.; Price, R. E.; Druschel, G.

    2011-12-01

    Milos is an island arc volcano venting submarine magmatic fluids directly into overlying seawater. Our study sites are located in an extensive shallow-water hydrothermal vent field less than 200 m offshore of Paleochori Bay in 5 m water depth. The vent fluids are highly sulfidic (> 3mM), at high-temperature (50-115C), and acidic (pH 5). The seafloor vent features include large patches (> 1 m2) of white microbial mats, patches of yellow elemental sulfur, and sediments stained orange by arsenic sulfides. The microbial communities that populate the shallow-sea hydrothermal vents stand in stark contrast to other nearshore environments typically found at wave base and within the photic zone. We explore sulfur isotope patterns along sharp environmental gradients established between ambient seawater and the efflux of vent fluids in the effort to better understand resource exploitation by microbial mat communities living in extreme conditions. Pore water samples, push-cores, biofilms, and water column samples were collected by SCUBA along sampling transects radiating out from the center of white mats into background sediments. We analyzed these samples for δ34S of dissolved sulfate, sulfide, elemental sulfur, and mineral sulfides (iron monosulfides and pyrite). Free gas sulfides collected directly from vents had δ34S values ranging +2.1 to +2.8%. Pore water sulfide, collected from below white mats with δ34S values ranging +1.9 to +2.9%, was isotopically similar to free gas samples. High pore water sulfate concentrations (8-25 mM) coupled with 34S-enriched pore water sulfides are not geochemical signatures indicative of dissimilatory sulfate reduction (where δ34Ssulfide <<0%). The δ34S of pore water sulfates collected across one dive site show a mixing trend, ranging from +18% in the center, +20% mid-transect, and +21% in sediments outside of the mat. This trend may be caused by oxidation of vent sulfides by entrained seawater (δ34S = +21.2%). We continue to target

  3. Hydrothermal Activity on the Southern Mid-Atlantic Ridge: Tectonically- and Volcanically-Hosted High Temperature Venting at 2-7 Degrees S

    NASA Astrophysics Data System (ADS)

    German, C. R.; Parson, L. M.; Murton, B. J.; Bennett, S. A.; Connelly, D. P.; Evans, A. J.; Prien, R. D.; Ramirez-Llodra, E. Z.; Shank, T. M.; Yoerger, D. R.; Jakuba, M.; Bradley, A. M.; Baker, E. T.; Nakamura, K.

    2005-12-01

    We have conducted a systematic investigation for hydrothermal activity along the southern Mid-Atlantic Ridge, 2°30-6°50 S. Our initial approach was to use a combination of multi-beam swath mapping, deep-tow sidescan sonar imaging and water column plume-detection using MAPRs and CTD-rosette system to locate new sites of hydrothermal activity immediately south of the Romanche and Chain Fracture zones. We wanted to test whether these geologic features represent a significant barrier to gene-flow along-axis away from northern MAR vent ecosystems. During the first leg of our research cruise (RRS Charles Darwin cruise CD169, Feb-Mar 2005) we used this approach to identify two hydrothermally active regions, one in a non-transform discontinuity near 4°S and the other in a segment centre characterised by very fresh sheet-flows near 5°S. During Leg 2 we returned to the second of these areas and deployed ABE, WHOI's autonomous underwater vehicle, in a three-phase strategy to prospect for, locate, and image new hydrothermal fields. During Phase 1 two discrete target areas were located ca. 1km apart along strike within the segment centre. During Phase 2 these two areas were each mapped in detail using an SM2000 system while in situ optical back scatter, Eh, temperature, Mn and Fe(II) sensors were used to confirm the interception of buoyant hydrothermal plumes rising from the seafloor. Finally we redeployed ABE (Phase 3) to collect photo-mosaics of each of two new vent-areas whilst simultaneously sampling their buoyant plumes by CTD-rosette for TDMn, Fe and CH4 analyses.

  4. The vent microbiome: patterns and drivers

    NASA Astrophysics Data System (ADS)

    Pachiadaki, M.

    2015-12-01

    Microbial processes within deep-sea hydrothermal vents affect the global biogeochemical cycles. Still, there are significant gaps in our understanding of the microbiology and the biogeochemistry of deep-sea hydrothermal systems. Vents differ in temperature, host rock composition and fluid chemistry; factors that are hypothesized to shape the distribution of the microbial communities, their metabolic capabilities and their activities. Using large-scale single cell genomics, we obtained insights into the genomic content of several linkages of a diffuse flow vent. The genomes show high metabolic versatility. Sulfur oxidation appears to be predominant but there is the potential of using a variety of e- donors and acceptors to obtain energy. To further assess the ecological importance of the vent auto- and heterotrophs, the global biogeography of the analyzed lineages will be investigated by fragment recruitment of metagenomes produced from the same site as well as other hydrothermal systems. Metatranscriptomic and metaproteomic data will be integrated to examine the expression of the predominant metabolic pathways and thus the main energy sources driving chemoautotrophic production. The comparative analysis of the key players and associated pathways among various vent sites that differ in physicochemical characteristics is anticipated to decipher the patterns and drivers of the global dispersion and the local diversification of the vent microbiome.

  5. The metallurgical integrity of the frit vent assembly diffusion bond

    NASA Astrophysics Data System (ADS)

    Ulrich, G. B.

    1994-06-01

    Iridium alloy clad vent sets (CVS's) are now being made by Energy Systems at the Oak Ridge Y-12 Plant. These CVS's are being made for the US Department of Energy's (NE-53) General Purpose Heat Source- Radioisotope Thermoelectric Generator (GPHS-RTG) program, which is to supply electrical power for the National Aeronautics and Space Administration's Cassini mission to Saturn. A GPHS-RTG has 72 CVS'. Each CVS encapsulates one (238)PuO2 fuel pellet. The helium gas produced from the alpha decay of the (238)Pu is vented through a nominal 0.45-mm-diam hole in the vent cup of each CVS. A frit vent assembly that is electron beam welded over the vent hole allows helium gas to escape but prevents plutonia fines from exiting. The metallurgical integrity of frit vent assemblies produced by Martin Marietta Energy Systems, Inc. (Energy Systems) were compared with those produced earlier by EG&G-Mound Applied Technology, Inc. (EG&G-MAT). Scanning electron microscope (SEM) photographs were taken (at magnifications of from 126x to 1,000x) of the starting frit vent powder and the diffusion-bonded powder in finished frit vent assemblies produced by Energy Systems and EG&G-MAT. Frit vent assemblies also were metallographically prepared and visually examined/photographed at magnifications of from 50x to 1,000x. The SEM and metallographic examinations of the particle-to-particle and particle-to-foil component diffusion bonds indicated that the Energy Systems-produced and EG&G-MAT-produced frit vent assemblies have comparable metallurgical integrity. Statistical analysis of the Energy Systems production data shows that the frit vent manufacturing yield is 91%.

  6. Effects of Vent Asymmetry on Explosive Eruptions

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D. E.

    2012-12-01

    Current computer models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the gas-thrust region. These effects on eruption direction may have implications for the formation of lateral blasts and pyroclastic density currents (PDCs). Here, we present preliminary results from numerical simulations using CartaBlanca, a Java based simulation tool for non-linear physics as developed at Los Alamos National Laboratory. Using 2D time-dependent simulations of explosive volcanic eruptions, we study the effects of vent asymmetry on a variety of eruptive conditions. Preliminary results suggest that asymmetric vent shape may provide an additional mechanism for the formation of lateral blasts and PDCs.

  7. Activated Carbon Fibers For Gas Storage

    SciTech Connect

    Burchell, Timothy D; Contescu, Cristian I; Gallego, Nidia C

    2017-01-01

    The advantages of Activated Carbon Fibers (ACF) over Granular Activated Carbon (GAC) are reviewed and their relationship to ACF structure and texture are discussed. These advantages make ACF very attractive for gas storage applications. Both adsorbed natural gas (ANG) and hydrogen gas adsorption performance are discussed. The predicted and actual structure and performance of lignin-derived ACF is reviewed. The manufacture and performance of ACF derived monolith for potential automotive natural gas (NG) storage applications is reported Future trends for ACF for gas storage are considered to be positive. The recent improvements in NG extraction coupled with the widespread availability of NG wells means a relatively inexpensive and abundant NG supply in the foreseeable future. This has rekindled interest in NG powered vehicles. The advantages and benefit of ANG compared to compressed NG offer the promise of accelerated use of ANG as a commuter vehicle fuel. It is to be hoped the current cost hurdle of ACF can be overcome opening ANG applications that take advantage of the favorable properties of ACF versus GAC. Lastly, suggestions are made regarding the direction of future work.

  8. Coupled pulsing of lava fountains: Video monitoring reveals systematic height and velocity variations of adjacent vents

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2014-05-01

    Lava fountains are a common eruption form at basaltic volcanoes. Many of the lava fountains occur at fissure eruptions, associated with the alignment of active vents. We observed that the lava fountain pulses may occur in chorus at several adjacent vents, implying that activity at these vents is coupled. The mechanisms behind such a coupling of adjacent lava fountains and the underlying connection between the different craters are not fully understood, however. Here we employ video images to measure the height, width and velocity of the ejecta leaving the vent. With a Sobel edge-detection algorithm, our aim is to measure the height of the different fountains occurring along fissure eruptions. Video data acquired from Puu'oo (Hawaii) and from Eyjafjallajökull (Iceland) are showing major similarities in fountaining behavior. Based on the fountain activity times series we estimate the sign and degree of correlation of the different vents. We find that the height and velocity of adjacent lava fountains are often in chorus. The velocity is calculated by a correlation in the Fourier space of contiguous images. We observed that episodically and sporadically the correlation regime can change. Despite these changes, both the frequency of the lava pulses and the eruption and rest time between the pulses remain similar for adjacent lava fountains, implying, a controlling process in the magma feeder system itself. We interpret the initial vertical velocity at the vent to be proportional to the extent of bubbles, and layers of bubbles rising. Lateral migration of fountains and their dynamics, in turn, is associated to lateral magma and gas flow or inclined layers of bubbles developing along the fissure at depth. Systematic recording and analysis of video data from different volcanoes hence result in a better understanding of the mechanisms of parallel and non-parallel lava fountain pulses.

  9. Speciation of dissolved copper within an active hydrothermal edifice on the Lucky Strike vent field (MAR, 37 degrees N).

    PubMed

    Sarradin, Pierre-Marie; Waeles, Matthieu; Bernagout, Solène; Le Gall, Christian; Sarrazin, Jozée; Riso, Ricardo

    2009-01-01

    The objective of this study was to determine the concentrations of different fractions of dissolved copper (after filtration at 0.45 microm) along the cold part of the hydrothermal fluid-seawater mixing zone on the Tour Eiffel edifice (MAR). Dissolved copper was analyzed by stripping chronopotentiometry (SCP) after chromatographic C(18) extraction. Levels of total dissolved copper (0.03 to 5.15 microM) are much higher than those reported for deep-sea oceanic waters but in accordance with data previously obtained in this area. Speciation measurements show that the hydrophobic organic fraction (C(18)Cu) is very low (2+/-1%). Dissolved copper is present mainly as inorganic and hydrophilic organic complexes (nonC(18)Cu). The distribution of copper along the pH gradient shows the same pattern for each fraction. Copper concentrations increase from pH 5.6 to 6.5 and then remain relatively constant at pH>6.5. Concentrations of oxygen and total sulphides demonstrate that the copper anomaly corresponds to the transition between suboxic and oxic waters. The increase of dissolved copper should correspond to the oxidative redissolution of copper sulphide particles formed in the vicinity of the fluid exit. The presence of such a secondary dissolved copper source, associated with the accumulation of metal sulphide particles, could play a significant role in the distribution of fauna in the different habitats available at vents.

  10. Adsorbed natural gas storage with activated carbon

    SciTech Connect

    Sun, Jian; Brady, T.A.; Rood, M.J.

    1996-12-31

    Despite technical advances to reduce air pollution emissions, motor vehicles still account for 30 to 70% emissions of all urban air pollutants. The Clean Air Act Amendments of 1990 require 100 cities in the United States to reduce the amount of their smog within 5 to 15 years. Hence, auto emissions, the major cause of smog, must be reduced 30 to 60% by 1998. Natural gas con be combusted with less pollutant emissions. Adsorbed natural gas (ANG) uses adsorbents and operates with a low storage pressure which results in lower capital costs and maintenance. This paper describes the production of an activated carbon adsorbent produced from an Illinois coal for ANG.

  11. Making Activated Carbon for Storing Gas

    NASA Technical Reports Server (NTRS)

    Wojtowicz, Marek A.; Serio, Michael A.; Suuberg, Eric M.

    2005-01-01

    Solid disks of microporous activated carbon, produced by a method that enables optimization of pore structure, have been investigated as means of storing gas (especially hydrogen for use as a fuel) at relatively low pressure through adsorption on pore surfaces. For hydrogen and other gases of practical interest, a narrow distribution of pore sizes <2 nm is preferable. The present method is a variant of a previously patented method of cyclic chemisorption and desorption in which a piece of carbon is alternately (1) heated to the lower of two elevated temperatures in air or other oxidizing gas, causing the formation of stable carbon/oxygen surface complexes; then (2) heated to the higher of the two elevated temperatures in flowing helium or other inert gas, causing the desorption of the surface complexes in the form of carbon monoxide. In the present method, pore structure is optimized partly by heating to a temperature of 1,100 C during carbonization. Another aspect of the method exploits the finding that for each gas-storage pressure, gas-storage capacity can be maximized by burning off a specific proportion (typically between 10 and 20 weight percent) of the carbon during the cyclic chemisorption/desorption process.

  12. Detailed dynamics and seasonal persistence of methane venting from lakes

    NASA Astrophysics Data System (ADS)

    Scandella, B. P.; Wood, H. G.; Ruppel, C. D.; Hemond, H.; Juanes, R.

    2012-12-01

    Lake-bottom sediments emit methane, a potent greenhouse gas, into the overlying water column and atmosphere. A large fraction of the methane is released as bubbles, but constraining the magnitude of this methane flux is challenging because ebullition is patchy in space and episodic in time. Extrapolating observations from individual methane seeps to a larger scale in time or space can result in severe over- or under-estimation of the methane flux, yet to date observations have not combined large, complete spatial coverage with multiple-season deployment periods. We present methane ebullition data from a fixed-location multibeam sonar, which observes a large area (420 m2) over a deployment period of over 6 months and with sufficient spatiotemporal resolution to detect individual bubbles. The large amount of data generated by the system presents a challenge to identify bubble signals that are infrequent, short in duration, and spatially compact. Addressing this challenge yields processed ebullition signals, which are compared against vents detected in the water column and near-surface sediment during geophysical surveys that utilize a commercial fishfinder sonar and a 4-24 kHz chirp seismic towfish. The ebullition signals are then used to develop conceptual models relating distributed methanogenesis to ebullition at localized sites. In particular, the spacing and persistence of vents implies potential mechanisms for their creation and maintenance, while the ebullitive response to hydrostatic pressure variations is used to validate a conduit dilation model of methane venting. Finally, the level of synchronicity in activity between distant venting sites suggests the relative importance of the external hydrostatic forcing over internal dynamics of methane generation. The mechanistic understanding provided by this work is critical to upscaling gas flow measurements from individual vents to infer lake-wide fluxes to the water column and atmosphere. Map of maximum sonar

  13. Evaluation of Soil Venting Application

    EPA Pesticide Factsheets

    The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by..

  14. Activity of antioxidant enzymes in response to atmospheric pressure induced physiological stress in deep-sea hydrothermal vent mussel Bathymodiolus azoricus.

    PubMed

    Martins, Inês; Romão, Célia V; Goulart, Joana; Cerqueira, Teresa; Santos, Ricardo S; Bettencourt, Raul

    2016-03-01

    Deep sea hydrothermal Bathymodiolus azoricus mussels from Portuguese EEZ Menez Gwen hydrothermal field possess the remarkable ability to overcome decompression and survive successfully at atmospheric pressure conditions. We investigated the potential use of antioxidant defense enzymes in mussel B. azoricus as biomarkers of oxidative stress induced by long term acclimatization to atmospheric pressure conditions. Mussels collected at Menez Gwen hydrothermal field were acclimatized for two weeks in three distinct conditions suitable of promoting physiological stress, (i) in plain seawater for concomitant endosymbiont bacteria loss, (ii) in plain seawater under metal iron exposure, (iii) constant bubbling methane and pumped sulfide for endosymbiont bacteria survival. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and iron storage proteins in addition to electrophoretic profiles were examined in vent mussel gills and digestive gland. Gills showed approximately 3 times more SOD specific activity than digestive glands. On the other hand, digestive glands showed approximately 6 times more CAT specific activity than gills. Iron storage proteins were identified in gill extracts from all experimental conditions mussels. However, in digestive gland extracts only fresh collected mussels and after 2 weeks in FeSO4 showed the presence of iron storage proteins. The differences between SOD, CAT specific activities and the presence of iron storage proteins in the examined tissues reflect dissimilar metabolic and antioxidant activities, as a result of tissue specificities and acclimatization conditions influences on the organism.

  15. The Evaluation of Antibacterial, Antifungal and Antioxidant Activity of Methanolic Extract of Mindium Laevigatum (Vent.) Rech. F., From Central Part of Iran

    PubMed Central

    Modaressi, Masoud; Shahsavari, Roia; Ahmadi, Farhad; Rahimi-Nasrabadi, Mehdi; Abiri, Ramin; Mikaeli, Ali; Batoli, Hossein

    2013-01-01

    Background Mindium laevigatum (Vent.) Rech. F. plant grows in central part of Iran. And used by local people as medical plant. Objectives The purpose of this study was to investigate the in vitro antibacterial, antifungal and antioxidant activities of the methanolic extracts of aerial and flower parts of plant. Materials and Methods The leaves and stem and flower of bark from M. laevigatum were separately collected, air-dried and powdered. Then the plant species extracts were prepared with methanol, water 80:20 and two polar and non-polar subfractions were realized. The antioxidant activity was evaluated by scavenging the radicals 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), β-Carotene linoleic acid assay and reducing power methods. The antifungal and antibacterial evaluation was performed by disc diffusion and minimum inhibitory concentration methods. Results The total phenolic analysis of subfractions found 182 ± 4.2 µg.gr-1 for polar and 158 ± 3.9 µg.gr-1 for non-polar extracts. The antifungal activity of the extracts against the various fungal varied from 14.0 to 34 mm. MIC values from 50 to 400 µg.mL-1 were satisfactory when compared with other plant products. The antibacterial results revealed that the subfraction extracts are mostly effective against Staphylococcus aureus. The antioxidant results showed polar subfraction has more activity against non-polar subfraction. Conclusion These findings demonstrated that the extract of Mindium laevigatum has remarkable in vitro antifungal and antioxidant activity. PMID:24624184

  16. Scientists as stakeholders in conservation of hydrothermal vents.

    PubMed

    Godet, Laurent; Zelnio, Kevin A; VAN Dover, Cindy L

    2011-04-01

    Hydrothermal vents are deep-sea ecosystems that are almost exclusively known and explored by scientists rather than the general public. Continuing scientific discoveries arising from study of hydrothermal vents are concommitant with the increased number of scientific cruises visiting and sampling vent ecosystems. Through a bibliometric analysis, we assessed the scientific value of hydrothermal vents relative to two of the most well-studied marine ecosystems, coral reefs and seagrass beds. Scientific literature on hydrothermal vents is abundant, of high impact, international, and interdisciplinary and is comparable in these regards with literature on coral reefs and seagrass beds. Scientists may affect hydrothermal vents because their activities are intense and spatially and temporally concentrated in these small systems. The potential for undesirable effects from scientific enterprise motivated the creation of a code of conduct for environmentally and scientifically benign use of hydrothermal vents for research. We surveyed scientists worldwide engaged in deep-sea research and found that scientists were aware of the code of conduct and thought it was relevant to conservation, but they did not feel informed or confident about the respect other researchers have for the code. Although this code may serve as a reminder of scientists' environmental responsibilities, conservation of particular vents (e.g., closures to human activity, specific human management) may effectively ensure sustainable use of vent ecosystems for all stakeholders.

  17. An improved back-flush-to-vent gas chromatographic method for determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia.

    PubMed

    Trubyanov, Maxim M; Mochalov, Georgy M; Vorotyntsev, Ilya V; Vorotyntsev, Andrey V; Suvorov, Sergey S; Smirnov, Konstantin Y; Vorotyntsev, Vladimir M

    2016-05-20

    A novel method for rapid, quantitative determination of trace permanent gases and carbon dioxide in ultra-high purity ammonia by dual-channel two-dimensional GC-PDHID is presented. An improved matrix back-flush-to-vent approach combining back-flush column switching technique with auxiliary NaHSO4 ammonia trap is described. The NaHSO4 trap prevents traces of ammonia from entering the analytical column and is shown not to affect the impurity content of the sample. The approach allows shortening the analysis time and increasing the amount of measurements without extensive maintenance of the GC-system. The performance of the configuration has been evaluated utilizing ammonia- and helium-based calibration standards. The method has been applied for the analysis of 99.9999+% ammonia purified by high-pressure distillation at the production site.

  18. 40 CFR 63.1034 - Closed vent systems and control devices; or emissions routed to a fuel gas system or process...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... devices; or emissions routed to a fuel gas system or process standards. 63.1034 Section 63.1034 Protection... routed to a fuel gas system or process standards. (a) Compliance schedule. The owner or operator shall...) Compliance standard. (1) Owners or operators routing emissions from equipment leaks to a fuel gas system...

  19. Measure Guideline: Passive Vents

    SciTech Connect

    Berger, David; Neri, Robin

    2016-02-05

    This document addresses the use of passive vents as a source of outdoor air in multifamily buildings. The challenges associated with implementing passive vents and the factors affecting performance are outlined. A comprehensive design methodology and quantified performance metrics are provided. Two hypothetical design examples are provided to illustrate the process. This document is intended to be useful to designers, decision-makers, and contractors implementing passive ventilation strategies. It is also intended to be a resource for those responsible for setting high-performance building program requirements, especially pertaining to ventilation and outdoor air. To ensure good indoor air quality, a dedicated source of outdoor air is an integral part of high-performance buildings. Presently, there is a lack of guidance pertaining to the design and installation of passive vents, resulting in poor system performance. This report details the criteria necessary for designing, constructing, and testing passive vent systems to enable them to provide consistent and reliable levels of ventilation air from outdoors.

  20. Fluid dynamics in explosive volcanic vents and craters

    NASA Astrophysics Data System (ADS)

    Ogden, Darcy

    2011-12-01

    Explosive volcanic jets can transition to buoyant plumes or collapse to form pyroclastic density currents depending on their ability to entrain and heat the ambient air. Recent one-dimensional (1D) analysis shows that fluid acceleration through volcanic vents and craters changes the velocity and pressures within these jets sufficiently enough to be a first order control on plume dimensions and therefore air entrainment and column stability (Koyaguchi et al., 2010). These 1D studies are only applicable to craters and vents with angles of less than about 30° to vertical. Using analytical formulations and numerical simulations, this study describes 2D effects of shallowly dipping vents and craters on volcanic eruptions. The effect of vents on acceleration and expansion of eruptive mixtures of ash and gas is described as a force imparted on the fluid by the vent wall, the wall force ( Fw). This force is a measure of the momentum coupling between an eruption and the solid earth that takes place in the vent. Rapid divergence of supersonic eruptive fluid within shallowly dipping vents occurs via Prandtl-Meyer expansion, which results in different pressure and velocity fields than those predicted by 1D analysis. This expansion decreases Fw and the vertical acceleration experienced by the eruptive fluid in the vent. For jets predicted by 1D analysis to exit the vent at supersonic velocities and at atmospheric pressure, this decrease in Fw will cause an increase in the predicted plume area, decreasing column stability. The complex 2D shape of volcanic vents can change jet structure (presence and location of shock waves) and preclude the development of jets that exit the vent supersonically with no internal standing shock waves (i.e., perfectly expanded or pressure balanced jets). These significant complications in jet structure and increase in plume radius may result in changes to air entrainment, plume stability, and tephra distribution.

  1. Quantifying diffuse and discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, Eric; EscartíN, Javier; Gracias, Nuno; Olive, Jean-Arthur; Barreyre, Thibaut; Davaille, Anne; Cannat, Mathilde; Garcia, Rafael

    2012-04-01

    The relative heat carried by diffuse versus discrete venting of hydrothermal fluids at mid-ocean ridges is poorly constrained and likely varies among vent sites. Estimates of the proportion of heat carried by diffuse flow range from 0% to 100% of the total axial heat flux. Here, we present an approach that integrates imagery, video, and temperature measurements to accurately estimate this partitioning at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperatures, photographic mosaics of the vent site, and video sequences of fluid flow were acquired during the Bathyluck'09 cruise (Fall, 2009) and the Momarsat'10 cruise (Summer, 2010) to the Lucky Strike hydrothermal field by the ROV Victor6000 aboard the French research vessel the "Pourquoi Pas"? (IFREMER, France). We use two optical methods to calculate the velocities of imaged hydrothermal fluids: (1) for diffuse venting, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time, and (2) for discrete jets, Particle Image Velocimetry tracks eddies by cross-correlation of pixel intensities between subsequent images. To circumvent video blurring associated with rapid velocities at vent orifices, exit velocities at discrete vents are calculated from the best fit of the observed velocity field to a model of a steady state turbulent plume where we vary the model vent radius and fluid exit velocity. Our results yield vertical velocities of diffuse effluent between 0.9 cm s-1 and 11.1 cm s-1 for fluid temperatures between 3°C and 33.5°C above that of ambient seawater, and exit velocities of discrete jets between 22 cm s-1 and 119 cm s-1 for fluid temperatures between 200°C and 301°C above ambient seawater. Using the calculated fluid velocities, temperature measurements, and photo mosaics of the actively venting areas, we calculate a heat flux due to diffuse venting from thin fractures of 3.15 ± 2.22 MW, discrete venting of

  2. Retrieving eruptive vent conditions from dynamical properties of unsteady volcanic plume using high-speed imagery and numerical simulations

    NASA Astrophysics Data System (ADS)

    Tournigand, Pierre-Yves; Taddeucci, Jacopo; José Peña Fernandez, Juan; Gaudin, Damien; Sesterhenn, Jörn; Scarlato, Piergiorgio; Del Bello, Elisabetta

    2016-04-01

    Vent conditions are key parameters controlling volcanic plume dynamics and the ensuing different hazards, such as human health issues, infrastructure damages, and air traffic disruption. Indeed, for a given magma and vent geometry, plume development and stability over time mainly depend on the mass eruption rate, function of the velocity and density of the eruptive mixture at the vent, where direct measurements are impossible. High-speed imaging of eruptive plumes and numerical jet simulations were here non-dimensionally coupled to retrieve eruptive vent conditions starting from measurable plume parameters. High-speed videos of unsteady, momentum-driven volcanic plumes (jets) from Strombolian to Vulcanian activity from three different volcanoes (Sakurajima, Japan, Stromboli, Italy, and Fuego, Guatemala) were recorded in the visible and the thermal spectral ranges by using an Optronis CR600x2 (1280x1024 pixels definition, 500 Hz frame rate) and a FLIR SC655 (640x480 pixels definition, 50 Hz frame rate) cameras. Atmospheric effects correction and pre-processing of the thermal videos were performed to increase measurement accuracy. Pre-processing consists of the extraction of the plume temperature gradient over time, combined with a temperature threshold in order to remove the image background. The velocity and the apparent surface temperature fields of the plumes, and their changes over timescales of tenths of seconds, were then measured by particle image velocimetry and thermal image analysis, respectively, of the pre-processed videos. The parameters thus obtained are representative of the outer plume surface, corresponding to its boundary shear layer at the interface with the atmosphere, and may significantly differ from conditions in the plume interior. To retrieve information on the interior of the plume, and possibly extrapolate it even at the eruptive vent level, video-derived plume parameters were non-dimensionally compared to the results of numerical

  3. Hydrothermal vent yields multitude of manganese

    NASA Astrophysics Data System (ADS)

    A rising plume of water from an active submarine hydrothermal spring discovered 500 km west of Newport, Ore., contains the highest concentrations of manganese yet reported, according to researchers at the U.S. Geological Survey in Menlo Park and at the University of Washington in Seattle. The vent, one of many submarine springs that have deposited large deposits of zinc- and silver-rich metals along the Juan de Fuca Ridge, may be a source of renewable minerals.‘The discovery of the active water discharge from the vent sites is particularly significant because it indicates that the polymetallic deposits are still being deposited and may represent a renewable mineral deposit,’ according to William R. Normark, a marine geologist with the USGS and chief scientist aboard the S. P. Lee, the USGS research ship that was used to collect water samples above the hydrothermal vent.

  4. Tracking Dissolved Methane Concentrations near Active Seeps and Gas Hydrates: Sea of Japan.

    NASA Astrophysics Data System (ADS)

    Snyder, G. T.; Aoki, S.; Matsumoto, R.; Tomaru, H.; Owari, S.; Nakajima, R.; Doolittle, D. F.; Brant, B.

    2015-12-01

    A number of regions in the Sea of Japan are known for active gas venting and for gas hydrate exposures on the sea floor. In this investigation we employed several gas sensors mounted on a ROV in order to determine the concentrations of dissolved methane in the water near these sites. Methane concentrations were determined during two-second intervals throughout each ROV deployment during the cruise. The methane sensor deployments were coupled with seawater sampling using Niskin bottles. Dissolved gas concentrations were later measured using gas chromatography in order to compare with the sensor results taken at the same time. The observed maximum dissolved methane concentrations were much lower than saturation values, even when the ROV manipulators were in contact with gas hydrate. Nonetheless, dissolved concentrations did reach several thousands of nmol/L near gas hydrate exposures and gas bubbles, more than two orders of magnitude over the instrumental detection limits. Most of the sensors tested were able to detect dissolved methane concentrations as low as 10 nmol/L which permitted detection when the ROV approached methane plume sites, even from several tens of meters above the sea floor. Despite the low detection limits, the methane sensors showed variable response times when returning to low-background seawater (~5nM). For some of the sensors, the response time necessary to return to background values occurred in a matter of minutes, while for others it took several hours. Response time, as well as detection limit, should be an important consideration when selecting methane sensors for ROV or AUV investigations. This research was made possible, in part, through funding provided by the Japanese Ministry of Economy, Trade and Industry (METI).

  5. Inside the Vent of the 2011-2012 Cordón Caulle Eruption, Chile: The Nature of a Rhyolitic Ash Plume Source

    NASA Astrophysics Data System (ADS)

    Tuffen, H.; Castro, J. M.; Schipper, C. I.; Wadsworth, F. B.

    2014-12-01

    The 2011-2012 activity at Cordon Caulle has provided an unprecedented opportunity to observe a sustained explosive rhyolitic eruption. An initial 27 hour Plinian phase commenced on 4 June 2011, followed by ten months of hybrid explosive-effusive activity, which generated disruptive ≤6 km ash plumes. In January 2012 our close observations of the active vent[1] revealed how episodic release of gas and ash from several sub-vents on an incipient lava dome (Fig. 1b) merged to form a sustained ash plume. Sub-vents ranged from metric point sources to arcuate fractures (>10 m) in the dome carapace. We visited the vent in January 2014, and found two ~50 m-wide, rubble-strewn vent areas adjacent to pancake-like obsidian domes, all within a breached, ~100 m-high tuff cone. Vent areas consist of fractured obsidian lava strewn by loose, rotated lava blocks ≤5 m across. Prominent red fracture surfaces (Fig. 1 d,e) occur in both the in-situ lava and the blocky veneer; these closely correspond to the type of sub-vents observed in 2012[1]. They range from smooth, curviplanar surfaces extending over several m to complex smaller-scale surfaces that follow pre-existing cooling joints in the lava carapace. In-situ fracture surfaces display prominent, predominantly vertical grooves and impact marks, but negligible displacement. Surfaces are coated by μm-mm thick veneers of fine-grained ash, to which larger ash-coated clasts have adhered. Veneer thickness and sintering degree strongly decrease towards the upper carapace of the lava. SEM analysis of ash veneers reveals 1) a high proportion of sub-micron clasts, 2) strong clast sintering, 3) abundant ash aggregation textures spanning submicron-mm scales, and 4) local surface scouring and corrosion of glass and phenocrysts. During ash venting the smallest particles are preferentially trapped on fracture surfaces and rapidly sintered, encouraging sub-vent blockage. Extensive ash aggregation may have been electrostatically aided, with

  6. 40 CFR 63.1015 - Closed vent systems and control devices; or emissions routed to a fuel gas system or process.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... devices; or emissions routed to a fuel gas system or process. 63.1015 Section 63.1015 Protection of... fuel gas system or process. (a) Compliance schedule. The owner or operator shall comply with this... flares used to comply with the provisions of this subpart shall design and operate the flare as...

  7. Soil microbial community changes as a result of long-term exposure to a natural CO 2 vent

    NASA Astrophysics Data System (ADS)

    Oppermann, B. I.; Michaelis, W.; Blumenberg, M.; Frerichs, J.; Schulz, H. M.; Schippers, A.; Beaubien, S. E.; Krüger, M.

    2010-05-01

    The capture and geological storage of CO 2 can be used to reduce anthropogenic greenhouse gas emissions. To assess the environmental impact of potential CO 2 leakage from deep storage reservoirs on the abundance and functional diversity of microorganisms in near-surface terrestrial environments, a natural CO 2 vent (>90% CO 2 in the soil gas) was studied as an analogue. The microbial communities were investigated using lipid biomarkers combined with compound-specific stable carbon isotope analyses, the determination of microbial activities, and the use of quantitative polymerase chain reactions (Q-PCR). With this complementary set of methods, significant differences between the CO 2-rich vent and a reference site with a normal CO 2 concentration were detected. The δ 13C values of the plant and microbial lipids within the CO 2 vent demonstrate that substantial amounts of geothermal CO 2 were incorporated into the microbial, plant, and soil carbon pools. Moreover, the numbers of Archaea and Bacteria were highest at the reference site and substantially lower at the CO 2 vent. Lipid biomarker analyses, Q-PCR, and the determination of microbial activities showed the presence of CO 2-utilising methanogenic Archaea, Geobacteraceae, and sulphate-reducing Bacteria (SRB) mainly at the CO 2 vent, only minor quantities were found at the reference site. Stable carbon isotopic analyses revealed that the methanogenic Archaea and SRB utilised the vent-derived CO 2 for assimilatory biosynthesis. Our results show a shift in the microbial community towards anaerobic and acidophilic microorganisms as a consequence of the long-term exposure of the soil environment to high CO 2 concentrations.

  8. Where are the undiscovered hydrothermal vents on oceanic spreading ridges?

    NASA Astrophysics Data System (ADS)

    Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.

    2015-11-01

    In nearly four decades since the discovery of deep-sea vents, one-third of the length of global oceanic spreading ridges has been surveyed for hydrothermal activity. Active submarine vent fields are now known along the boundaries of 46 out of 52 recognized tectonic plates. Hydrothermal survey efforts over the most recent decade were sparked by national and commercial interests in the mineral resource potential of seafloor hydrothermal deposits, as well as by academic research. Here we incorporate recent data for back-arc spreading centers and ultraslow- and slow-spreading mid-ocean ridges (MORs) to revise a linear equation relating the frequency of vent fields along oceanic spreading ridges to spreading rate. We apply this equation globally to predict a total number of vent fields on spreading ridges, which suggests that ~900 vent fields remain to be discovered. Almost half of these undiscovered vent fields (comparable to the total of all vent fields discovered during 35 years of research) are likely to occur at MORs with full spreading rates less than 60 mm/yr. We then apply the equation regionally to predict where these hydrothermal vents may be discovered with respect to plate boundaries and national jurisdiction, with the majority expected to occur outside of states' exclusive economic zones. We hope that these predictions will prove useful to the community in the future, in helping to shape continuing ridge-crest exploration.

  9. Vented target elements for use in an isotope-production reactor. [LMFBR

    DOEpatents

    Cawley, W.E.; Omberg, R.P.

    1982-08-19

    A method is described for producing tritium gas in a fast breeder reactor cooled with liquid metal. Lithium target material is placed in pins equipped with vents, and tritium gas is recovered from the coolant.

  10. 77 FR 59209 - Information Collection Activities: Oil and Gas Production Requirements; Proposed Collection...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-26

    ...: Evaluate requests to burn liquid hydrocarbons and vent and flare gas to ensure that these requests are... reservoirs are being depleted in a manner that will lead to the greatest ultimate recovery of hydrocarbons. This information is collected to determine the capability of hydrocarbon wells and to evaluate...

  11. Safe venting of hydrogen

    SciTech Connect

    Stewart, W.F.; Dewart, J.M.; Edeskuty, F.J.

    1990-01-01

    The disposal of hydrogen is often required in the operation of an experimental facility that contains hydrogen. Whether the vented hydrogen can be discharged to the atmosphere safely depends upon a number of factors such as the flow rate and atmospheric conditions. Calculations have been made that predict the distance a combustible mixture can extend from the point of release under some specified atmospheric conditions. Also the quantity of hydrogen in the combustible cloud is estimated. These results can be helpful in deciding of the hydrogen can be released directly to the atmosphere, or if it must be intentionally ignited. 15 refs., 5 figs., 2 tabs.

  12. Enhanced Emergency Smoke Venting

    DTIC Science & Technology

    1988-07-01

    Boeing Airworthiness Offices in both Renton and Everett. The search disclosed at least 26 letters between Boeing and the FAA on the subject of smoke...the ventilation airflow rates and utilizing the effect of the additional outflow valve. .-. 12 FAA Report No. DOT/ FAA /CT-86/41-I, " Aircraft ...lTr !r DOT/ FAA !CT-88/22 Enhanced Emergency FAA Technical Center Sm oke Atlantic City International Airport Venting N.J. 08405 T.DTIC, Q\\SEP 0 21988

  13. Tornado protection by venting

    SciTech Connect

    Cavanagh, C.A.

    1987-01-01

    The purpose of this paper is to demonstrate the ability to protect a modern nuclear power plant from the effects of a tornado by the use of a system of venting in all safety-related structures outside of the containment. The paper demonstrates this by presenting a method of analysis and of equipment selection that fully complies with the intent and the letter of applicable federal regulatory guides. A report of an actual tornado in the City of Kalamazoo, Michigan, suggests that the concept of sealing a plant during a tornado may not always be applicable.

  14. Anti-arthritic activity of root bark of Oroxylum indicum (L.) vent against adjuvant-induced arthritis

    PubMed Central

    Karnati, Mamatha; Chandra, Rodda H; Veeresham, Ciddi; Kishan, Bookya

    2013-01-01

    Background: Oroxylum indicum (Bignoniaceae) also known as Sonapatha is an indigenous medicinal plant widely used in Ayurvedic medicine for over thousands of years. It is an active ingredient of well-known Ayurvedic formulations such as Chyawanprash and Dasamula. Root bark of this plant has tonic and astringent properties and it is also used in rheumatism. Objective: The present investigation was carried out to evaluate the anti-arthritic activity of different extracts of root bark of Oroxylum indicum against adjuvant - induced arthritis in rats. Materials and Methods: Male Wistar rats were used in this study. Arthritis was induced by injecting 0.1 ml Freund's complete adjuvant intra-dermally into the left hind paw of the rats. The paw volume, hematological, biochemical, radiographic and histopathological aspects were evaluated. Results: The relative percentage inhibition potential of paw volume in rats treated with various extracts of Oroxylum indicum was found to be ethyl acetate extract (67.69%) >chloroform extract (64.61%) >n-butanol extract (58.46%) respectively. The hematological parameters like RBC count, hemoglobin content showed significant increase while there was a significant decrease in total WBC count and ESR in all the groups of animals pretreated with root bark extracts. The biochemical parameters such as catalase, glutathione contents showed a significant increase while the lipid peroxide and Cathepsin-D content decreased significantly only in case of ethyl acetate pretreated rats when compared to others. Conclusion: The present study suggests that the chloroform, ethyl acetate and n-butanol extracts of root bark of Oroxylum indicum exhibit anti-arthritic activity. The order of activity of extracts was found to be ethyl acetate >chloroform >n-butanol respectively. PMID:23798888

  15. Vented Tank Resupply Experiment--Flight Test Results

    NASA Technical Reports Server (NTRS)

    Chato, David J.; Martin, Timothy A.

    1997-01-01

    This paper reports the results of the Vented Tank Resupply Experiment (VTRE) which was flown as a payload on STS 77. VTRE looks at the ability of vane Propellant Management Devices (PMD) to separate liquid and gas in low gravity. VTRE used two clear 0.8 cubic foot tanks one spherical and one with a short barrel section and transferred Refrigerant 113 between them as well as venting it to space. Tests included retention of liquid during transfer, liquid free venting, and recovery of liquid into the PMD after thruster firing. Liquid was retained successfully at the highest flow rate tested (2.73 gpm). Liquid free vents were achieved for both tanks, although at a higher flow rate (0.1591 cfm) for the spherical tank than the other (0.0400 cfm). Recovery from a thruster firing which moved the liquid to the opposite end of the tank from the PMD was achieved in 30 seconds.

  16. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Case Iron Soil Pipe and Fittings, or, Silicone Rubber, Low and High Temperature and Tear Resistant... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Vents and venting. 3280.611 Section 3280.611 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  17. 24 CFR 3280.611 - Vents and venting.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... this section and as otherwise required by this standard. (b) Materials—(1) Pipe. Vent piping shall be... listed materials. (2) Fittings. Appropriate fittings shall be used for all changes in direction or size and where pipes are joined. The material and design of vent fittings shall conform to the type...

  18. Investigation of shallow gas hydrate occurrence and gas seep activity on the Sakhalin continental slope, Russia

    NASA Astrophysics Data System (ADS)

    Jin, Young Keun; Baranov, Boris; Obzhirov, Anatoly; Salomatin, Alexander; Derkachev, Alexander; Hachikubo, Akihiro; Minami, Hrotsugu; Kuk Hong, Jong

    2016-04-01

    The Sakhalin continental slope has been a well-known gas hydrate area since the first finding of gas hydrate in 1980's. This area belongs to the southernmost glacial sea in the northern hemisphere where most of the area sea is covered by sea ice the winter season. Very high organic carbon content in the sediment, cold sea environment, and active tectonic regime in the Sakhalin slope provide a very favorable condition for occurring shallow gas hydrate accumulation and gas emission phenomena. Research expeditions under the framework of a Korean-Russian-Japanese long-term international collaboration projects (CHAOS, SSGH-I, SSGH-II projects) have been conducted to investigate gas hydrate occurrence and gas seepage activities on the Sakhalin continental slope, Russia from 2003 to 2015. During the expeditions, near-surface gas hydrate samples at more than 30 sites have been retrieved and hundreds of active gas seepage structures on the seafloor were newly registered by multidisciplinary surveys. The gas hydrates occurrence at the various water depths from about 300 m to 1000 m in the study area were accompanied by active gas seepage-related phenomena in the sub-bottom, on the seafloor, and in the water column: well-defined upward gas migration structures (gas chimney) imaged by high-resolution seismic, hydroacoustic anomalies of gas emissions (gas flares) detected by echosounders, seafloor high backscatter intensities (seepage structures) imaged by side-scan sonar and bathymetric structures (pockmarks and mounds) mapped by single/multi-beam surveys, and very shallow SMTZ (sulphate-methane transition zone) depths, strong microbial activities and high methane concentrations measured in sediment/seawater samples. The highlights of the expeditions are shallow gas hydrate occurrences around 300 m in the water depth which is nearly closed to the upper boundary of gas hydrate stability zone in the area and a 2,000 m-high gas flare emitted from the deep seafloor.

  19. VentSim: a simulation model of cardiopulmonary physiology.

    PubMed

    Rutledge, G W

    1994-01-01

    VentSim is a quantitative model that predicts the effects of alternative ventilator settings on the cardiopulmonary physiology of critically ill patients. VentSim is an expanded version of the physiologic model in VentPlan, an application that provides ventilator-setting recommendations for patients in the intensive care unit. VentSim includes a ventilator component, an airway component, and a circulation component. The ventilator component predicts the pressures and airflows that are generated by a volume-cycled, constant-flow ventilator. The airway component has anatomic and physiologic deadspace compartments, and two alveolar compartments that participate in gas exchange with two pulmonary blood-flow compartments in the circulatory component. The circulatory component also has a shunt compartment that allows a fraction of blood flow to bypass gas exchange in the lungs, and a tissue compartment that consumes oxygen and generates carbon dioxide. The VentSim model is a set of linked first-order difference equations, with control variables that correspond to the ventilator settings, dependent variables that correspond to the physiologic state, and one independent variable, time. Because the model has no steady state solution, VentSim solves the equations by numeric integration, which is computation intensive. Simulation results demonstrate that VentSim predicts the effects of a variety of physiologic abnormalities that cannot be represented in less complex models such as the VentPlan model. For a ventilator-management application, the time-critical nature of ventilator-setting decisions limits the use of complex models. Advanced ventilator-management applications may include a mechanism to select patient-specific models that balance the trade-off of benefit of model detail and cost of computation delay.

  20. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... vents must penetrate into tanks at the top of the vapor space, the following methods of venting and the... the vent shall terminate in a gooseneck bend and shall be located at a reasonable height above...

  1. Water vent design for Space Station Freedom

    NASA Astrophysics Data System (ADS)

    Miernik, Janie H.; Worden, Edson A.; Bedard, John E.; Lieu, Bing H.

    1992-07-01

    Space Stadon Freedom (SSF) will be required to vent water during non-quiescent periods. During Man Tended Configuration (MTC), before the Environmental Control and Life Support System (ECLSS) water loop is closed, humidity condensate will be periodically vented. At Permanently Manned Configuration (PMC), water will be vented on contingency if there is excess water on SSF. The thrust due to venting must be minimized to be considered non-propulsive. Also, ice formation and clogging of the vent nozzle must be avoided. Many aspects of the Space Shuttle water vent design were utilized in development of the preliminary SSF water vent design presented in this paper. Design modifications which improved the shuttle vent as well as those necessary for SSF are discussed. The exterior vent location, direction and environment on SSF are unique compared to previous space water vent designs. From data collected in the vent tests and analyses, a finalized SSF water vent design will be developed.

  2. EVALUATION OF SOIL VENTING APPLICATION

    EPA Science Inventory

    The ability of soil venting to inexpensively remove large amounts of volatile organic compounds (VOCs) from contaminated soils is well established. However, the time required using venting to remediate soils to low contaminant levels often required by state and federal regulators...

  3. Transient seafloor venting from methane hydrate dissociation on continental slopes

    NASA Astrophysics Data System (ADS)

    Darnell, K.; Flemings, P. B.

    2014-12-01

    We present model results of hydrate dynamics that show the development of a gas chimney at three-phase equilibrium where gas flows through the marine hydrate stability zone and vents into the ocean during transient adjustment to imposed warming. Previous studies show venting occurs at the seaward retreating up-dip boundary of the hydrate stability zone during warming, whereas our results are the first to provide a mechanism for temporary gas venting vertically through the hydrate stability zone during warming. Transient behavior records the combined effect of hydrate dissociation from seafloor warming and secondary hydrate formation from gas produced by hydrate dissociation. We perform simulations of seafloor warming with a 1-d, unsteady, multiphase, fluid-flow model of methane hydrate dynamics. We assume an initial hydrate layer 6o meters thick with 10% pore volume saturation with seawater occupying the remaining domain above and below. We apply an instantaneous temperature increase at the seafloor. The temperature increase propagates downward through the deposit and initiates hydrate dissociation at the base of the deposit. Gas sourced from dissociation migrates upward and re-solidifies as hydrate to a maximum saturation set by a three-phase equilibrium salinity constraint. Additional gas migrates further upward to repeat the process. A chimney defined by dissociation at the bottom, secondary hydrate formation at the top, and maintained at three-phase equilibrium on the interior propagates to the seafloor in 10 kyr. Gas and salt then exit the system by venting into the ocean until dissociation stops producing new gas. Elevated salinities then diffuse to background seawater values. A shorter, shoaled hydrate deposit remains after ~100 kyr. This result shows that temporary venting can potentially occur anywhere along the hydrate stability zone during seafloor warming while retaining a hydrate deposit at steady state.

  4. Vent sizing: analysis of the blowdown of a hybrid non tempered system.

    PubMed

    Véchot, Luc; Minko, Wilfried; Bigot, Jean-Pierre; Kazmierczak, Marc; Vicot, Patricia

    2011-07-15

    The runaway and blowdown of a non tempered hybrid chemical system (30% cumene hydroperoxide) exposed to an external heat input was investigated using a 0.1l scale tool. The maximum temperature and the maximum temperature rise rate were showed to be sensitive to the vent size. An Antoine type correlation between the maximum temperatures and pressures was observed. These resulted from the presence of vapour, mainly generated by the reaction products. Increasing the initial filling ratio resulted in an earlier vent opening but did not have a significant influence on the blow-down. Three types of mass venting behaviour were observed, when changing the vent area to volume ratio (A/V): • for large A/V, two-phase venting occurred from the vent opening until the end of the second pressure peak; • for medium A/V, two-phase venting occurred before and after the turnaround. The data seem to indicate that gas only venting occurred at turn-around; • for low A/V, two-phase venting was observed only after the second pressure peak. Two-phase venting after the second pressure peak probably results from the boiling of the hot reaction products at low pressure.

  5. Did the Mississippian Lodgepole buildup at Dickinson Field (North Dakota) form as a gas seep ({open_quotes}vent{close_quotes}) community?

    SciTech Connect

    Longman, M.W.

    1996-10-01

    The Lower Mississippian Lodgepole carbonate buildup reservoir at Dickinson Field in Stark County, North Dakota, has been widely reported as being a Waulsortian (or Waulsortian-like) mound. The term {open_quotes}Waulsortian mound{close_quotes} is used for a variety of Early Mississippian carbonate buildups that share a number of features including an abundance of carbonate mud, a {open_quotes}framework{close_quotes} of organisms such as fenestrate bryozoans and crinoids that tended to trap or baffle sediment, and a general absence of marine-cemented reef framework. Although the age of the Lodgepole mound at Dickinson Field qualifies it to be a Waulsortian mound, petrographic study of cores reveals that the reservoir rocks are quite unlike those in true Waulsortian mounds. Instead of being dominated by carbonate mud, the Lodgepole mound core is dominated by marine cement. Furthermore, ostracods and microbial limestones are common in the mound core where they occur with crinoid debris and small amounts of bryozoan, coral, and brachiopod debris. The abundant microbial limestones and marine cement indicate that the Dickinson mound formed as a lithified reef on the sea floor rather than as a Waulsortian mud mound. The microbial limestones, marine cement, and common ostracods in the mount core, and the fact that the mound nucleated almost directly o top of the Bakken Shale, suggest that the Dickinson Lodgepole mound formed at the site of a submarine spring and gas seep.

  6. Video monitoring reveals pulsating vents and propagation path of fissure eruption during the March 2011 Pu'u 'Ō'ō eruption, Kilauea volcano

    NASA Astrophysics Data System (ADS)

    Witt, Tanja; Walter, Thomas R.

    2017-01-01

    Lava fountains are a common eruptive feature of basaltic volcanoes. Many lava fountains result from fissure eruptions and are associated with the alignment of active vents and rising gas bubbles in the conduit. Visual reports suggest that lava fountain pulses may occur in chorus at adjacent vents. The mechanisms behind such a chorus of lava fountains and the underlying processes are, however, not fully understood. The March 2011 eruption at Pu'u 'Ō'ō (Kilauea volcano) was an exceptional fissure eruption that was well monitored and could be closely approached by field geologists. The fissure eruption occurred along groups of individual vents aligned above the feeding dyke. We investigate video data acquired during the early stages of the eruption to measure the height, width and velocity of the ejecta leaving eight vents. Using a Sobel edge-detection algorithm, the activity level of the lava fountains at the vents was determined, revealing a similarity in the eruption height and frequency. Based on this lava fountain time series, we estimate the direction and degree of correlation between the different vents. We find that the height and velocity of the eruptions display a small but systematic shift in time along the vents, indicating a lateral migration of lava fountaining at a rate of 11 m/s from W to E. This finding is in agreement with a propagation model of a pressure wave originating at the Kilauea volcano and propagating through the dyke at 10 m/s from W to E. Based on this approach from videos only 30 s long, we are able to obtain indirect constraints on the physical dyke parameters, with important implications for lateral magma flow processes at depth. This work shows that the recording and analysis of video data provide important constraints on the mechanisms of lava fountain pulses. Even though the video sequence is short, it allows for the confirmation of the magma propagation direction and a first-order estimation of the dyke dimensions.

  7. 78 FR 59650 - Subzone 9F, Authorization of Production Activity, The Gas Company, LLC dba Hawai'i Gas...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-27

    ... Foreign-Trade Zones Board Subzone 9F, Authorization of Production Activity, The Gas Company, LLC dba Hawai'i Gas, (Synthetic Natural Gas), Kapolei, Hawaii On May 22, 2013, The Gas Company, LLC dba Hawai'i Gas submitted a notification of proposed production activity to the Foreign-Trade Zones (FTZ)...

  8. Activation of catalysts for synthesizing methanol from synthesis gas

    DOEpatents

    Blum, David B.; Gelbein, Abraham P.

    1985-01-01

    A method for activating a methanol synthesis catalyst is disclosed. In this method, the catalyst is slurried in an inert liquid and is activated by a reducing gas stream. The activation step occurs in-situ. That is, it is conducted in the same reactor as is the subsequent step of synthesizing methanol from a methanol gas stream catalyzed by the activated catalyst still dispersed in a slurry.

  9. 40 CFR 65.143 - Closed vent systems.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or a... bypass line. (ii) Secure the bypass line valve in the non-diverting position with a car-seal or a lock... procedures specified in Method 21 of appendix A of 40 CFR part 60. (v) Calibration gases shall be...

  10. 10 CFR Appendix O to Subpart B of... - Uniform Test Method for Measuring the Energy Consumption of Vented Home Heating Equipment

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... determine the concentration by volume of carbon dioxide present in the dry gas with instrumentation which... vent terminal which is not equipped with a draft control device, designed to open the venting system when the appliance is in operation and to close the venting system when the appliance is in a...

  11. Carbon fluxes from hydrothermal vents off Milos, Aegean Volcanic Arc, and the influence of venting on the surrounding ecosystem.

    NASA Astrophysics Data System (ADS)

    Dando, Paul; Aliani, Stefano; Bianchi, Nike; Kennedy, Hilary; Linke, Peter; Morri, Carla

    2014-05-01

    The island of Milos, in the Aegean Sea, has extensive hydrothermal fields to the east and southeast of the island with additional venting areas near the entrance to and within the central caldera. A calculation of the total area of the vent fields, based on ship and aerial surveys, suggested that the hydrothermal fields occupy 70 km2, twice the area previously estimated. The vents ranged in water depth from the intertidal to 300 m. As a result of the low depths there was abundant free gas release: in places water boiled on the seabed. The stream of gas bubbles rising through the sandy seabed drove a shallow re-circulation of bottom seawater. The majority of the water released with the gas, with a mean pH of 5.5, was re-circulated bottom water that had become acidified in contact with CO2 gas and was often diluted by admixture with the vapour phase from the deeper fluids. The major component of the free gas, 80%, was CO2, with an estimated total flux of 1.5-7.5 x 1012 g a-1. The methane flux, by comparison, was of the order of 1010 g a.-1 Using methane as a tracer it was shown that the major gas export from the vents was below the thermocline towards the southwest, in agreement with the prevailing currents. Areas of hydrothermal brine seepage occurred between the gas vents and occasional brine pools were observed in seabed depressions. Under relatively calm conditions, many of the brine seeps were covered by thick minero-bacterial mats consisting of silica and sulphur and surrounded by mats of diatoms and cyanobacteria. The minerals were not deposited in the absence of bacteria. Storms disrupted the mats, leading to an export of material to the surrounding area. Stable isotope data from sediments and sediment trap material suggested that exported POM was processed by zooplankton. The combined effects of the geothermal heating of the seabed, the large gas flux, variation in the venting and the effect of the brine seeps had a dramatic effect on the surrounding

  12. Contamination of the space station environment by vented chemicals

    NASA Technical Reports Server (NTRS)

    Bernhardt, Paul A.

    1988-01-01

    Gaseous materials vented from materials and life science experiments on the Space Station may have noticeable effects on the optical or plasma environment. The magnitude of the effects depends on: (1) rarefied gas dynamics; (2) photochemical reactions; and (3) airglow excitation mechanisms. In general, the effects from atomic species can be mitigated, but the disturbances resulting from venting of molecules like SF6, CO2 and C2H2 can be significant. The interaction of molecules with ambient plasma at orbital velocities should be studied with laboratory or space experiments.

  13. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-13 Venting... outlet connections of the valves. (b) Threads for openings shall be National Gas Taper Threads...

  14. Explosion hazards of LPG-air mixtures in vented enclosure with obstacles.

    PubMed

    Zhang, Qi; Wang, Yaxing; Lian, Zhen

    2017-04-01

    Numerical simulations were performed to study explosion characteristics of liquefied petroleum gas (LPG) explosion in enclosure with a vent. Unlike explosion overpressure and dynamic pressure, explosion temperature of the LPG-air mixture at a given concentration in a vented enclosure has very little variation with obstacle numbers for a given blockage ratio. For an enclosure without obstacle, explosion overpressures for the stoichiometric mixtures and the fuel-lean mixtures reach their maximum within the vent and that for fuel-rich mixture reaches its maximum beyond and near the vent. Dynamic pressures produced by an indoor LPG explosion reach their maximum always beyond the vent no matter obstacles are present or not in the enclosure. A LPG explosion in a vented enclosure with built-in obstacles is strong enough to make the brick and mortar wall with a thickness of 370mm damaged. If there is no obstacle in the enclosure, the lower explosion pressure of several kPa can not break the brick and mortar wall with a thickness of 370mm. For a LPG explosion produced in an enclosure with a vent, main hazards, within the vent, are overpressure and high temperature. However main hazards are dynamic pressure, blast wind, and high temperature beyond the vent.

  15. Measurement of atmospheric pollutants associated with oil and natural gas exploration and production activity in Pennsylvania's Allegheny National Forest.

    PubMed

    Pekney, Natalie J; Veloski, Garret; Reeder, Matthew; Tamilia, Joseph; Rupp, Erik; Wetzel, Alan

    2014-09-01

    Oil and natural gas exploration and production (E&P) activities generate emissions from diesel engines, compressor stations, condensate tanks, leaks and venting of natural gas, construction of well pads, and well access roads that can negatively impact air quality on both local and regional scales. A mobile, autonomous air quality monitoring laboratory was constructed to collect measurements of ambient concentrations of pollutants associated with oil and natural gas E&P activities. This air-monitoring laboratory was deployed to the Allegheny National Forest (ANF) in northwestern Pennsylvania for a campaign that resulted in the collection of approximately 7 months of data split between three monitoring locations between July 2010 and June 2011. The three monitoring locations were the Kane Experimental Forest (KEF) area in Elk County, which is downwind of the Sackett oilfield; the Bradford Ranger Station (BRS) in McKean County, which is downwind of a large area of historic oil and gas productivity; and the U.S. Forest Service Hearts Content campground (HC) in Warren County, which is in an area relatively unimpacted by oil and gas development and which therefore yielded background pollutant concentrations in the ANF. Concentrations of criteria pollutants ozone and NO2 did not vary significantly from site to site; averages were below National Ambient Air Quality Standards. Concentrations of volatile organic compounds (VOCs) associated with oil and natural gas (ethane, propane, butane, pentane) were highly correlated. Applying the conditional probability function (CPF) to the ethane data yielded most probable directions of the sources that were coincident with known location of existing wells and activity. Differences between the two impacted and one background site were difficult to discern, suggesting the that the monitoring laboratory was a great enough distance downwind of active areas to allow for sufficient dispersion with background air such that the localized

  16. The Prevention of Ice Formation on Gasoline Tank Vents

    NASA Technical Reports Server (NTRS)

    Theodorsen, Theodore; Clay, William C

    1931-01-01

    This investigation was conducted in the refrigerated wind tunnel at the Langley Memorial Aeronautical Laboratory, Langley Field, Va., to determine a suitable method for preventing the formation of ice on the vents of airplane gasoline tanks. Tests were made on a variety of vent forms arranged in a number of different orientations relative to the direction of the air stream. Both the size of the tube and its orientation were found to be of great importance. Small tubes, under equal circumstances, were found to freeze over far more rapidly than large ones. Tubes pointing downstream, or shielded in other ways, appear to be perfectly immune against this hazard. A tube 3/4 inch in diameter with the opening pointing downstream is finally recommended as being the safest choice of gas tank vent.

  17. Electricity generation from hydrothermal vents

    NASA Astrophysics Data System (ADS)

    Aryadi, Y.; Rizal, I. S.; Fadhli, M. N.

    2016-09-01

    Hydrothermal vent is a kind of manifestation of geothermal energy on seabed. It produces high temperature fluid through a hole which has a diameter in various range between several inches to tens of meters. Hydrothermal vent is mostly found over ocean ridges. There are some 67000 km of ocean ridges, 13000 of them have been already studied discovering more than 280 sites with geothermal vents. Some of them have a thermal power of up to 60 MWt. These big potential resources of energy, which are located over subsea, have a constraint related to environmental impact to the biotas live around when it becomes an object of exploitation. Organic Rankine Cycle (ORC) is a method of exploiting heat energy to become electricity using organic fluid. This paper presents a model of exploitation technology of hydrothermal vent using ORC method. With conservative calculation, it can give result of 15 MWe by exploiting a middle range diameter of hydrothermal vent in deep of 2000 meters below sea level. The technology provided here really has small impact to the environment. With an output energy as huge as mentioned before, the price of constructing this technology is low considering the empty of cost for drilling as what it should be in conventional exploitation. This paper also presents the comparison in several equipment which is more suitable to be installed over subsea.

  18. Hot vents in an ice-cold ocean: Indications for phase separation at the southernmost area of hydrothermal activity, Bransfield Strait, Antarctica

    NASA Astrophysics Data System (ADS)

    Dählmann, A.; Wallmann, K.; Sahling, H.; Sarthou, G.; Bohrmann, G.; Petersen, S.; Chin, C. S.; Klinkhammer, G. P.

    2001-12-01

    During the expeditions ANT-XV/2 with R/V Polarstern in 1997/98 and NBP 99-04 with R/V IB N.B. Palmer in 1999, the first samples of hydrothermally influenced sediments of Bransfield Strait were obtained at Hook Ridge, a volcanic edifice in the Central Basin of the Strait. The vent sites are characterized by white siliceous crusts on top of the sediment layer and temperatures measured immediately on deck are up to 48.5°C. The shallow depth of these vent sites (1050 m) particularly controls the chemistry of the pore fluids that are enriched in silica and sulfide and show low pH values. Chloride is depleted up to 20% and the calculated hydrothermal endmember concentration is in the range of 1-84 mM. Since other mechanisms for Cl depletion can be ruled out clearly, the composition of this fluid is attributed to phase separation. While the Cl-depleted fluid is emanating at Hook Ridge, a Cl-enriched fluid can be identified in the adjacent King George Basin. Using a p,x diagram the two corresponding endmember concentrations reveal that the phase separation takes place at subcritical conditions (total depth: ˜2500 m), probably along the whole volcanic edifice.

  19. Effect of cadmium, copper and mercury on antioxidant enzyme activities and lipid peroxidation in the gills of the hydrothermal vent mussel Bathymodiolus azoricus.

    PubMed

    Company, R; Serafim, A; Bebianno, M J; Cosson, R; Shillito, B; Fiala-Médioni, A

    2004-01-01

    Metals are known to influence lipid peroxidation and oxidative status of marine organisms. Hydrothermal vent mussels Bathymodiolus azoricus live in deep-sea environments with anomalous conditions, including high metal concentrations. Although B. azoricus are aerobic organisms they possess abundant methano and thioautotrophic symbiotic bacteria in the gills. The enzymatic defences (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidase (Total GPx) and selenium-dependent glutathione peroxidase (Se-GPx)) and lipid peroxidation were determined in the gills of B. azoricus exposed to Cd (0.9 microM), Cu (0.4 microM) and Hg (0.1 microM) with different times of exposure. The experiments were performed in pressurized containers at 9+/-1 degrees C and 85 bars. Results show that vent mussels possess antioxidant enzymatic protection in the gills. Cd and Cu had an inhibitory effect in the enzymatic defence system, contrarily to Hg. These enzymatic systems are not completely understood in the B. azoricus, since reactive oxygen species might be produced through other processes than natural redox cycling, due to hydrogen sulphide and oxygen content present. Also the symbiotic bacteria may play an important contribution in the antioxidant protection of the gills.

  20. Subtle and Not-So-Subtle Variability in Very-Long-Period Earthquakes at Fuego Volcano, Guatemala Reveal Details on Vent Location and Eruption Style

    NASA Astrophysics Data System (ADS)

    Waite, G. P.; Brill, K. A.; Lyons, J. J.; Nadeau, P. A.

    2012-12-01

    Repeated short-term deployments of seismic, infrasound, video, and gas-emission instruments at Fuego volcano, Guatemala have revealed three types of very-long-period (VLP) earthquakes associated with conduit sealing, pressure accumulation, and release. Major differences in waveforms are due to changes in vent locations. Vulcanian explosions and gas puffing from the summit vent produce waveforms that differ only slightly in peak period. Vulcanian explosions from a flank vent produce very different VLP waveforms. In January 2008, ash-rich, vulcanian explosions issued from a vent on the western flank and produced a distinct type of VLP (Type 1). Bomb-rich explosions from the summit vent in January 2009 produced a much shorter duration VLP (Type 2), but a vulcanian-style ash release. Type 3 VLP events occurred during ash-free exhalations from the summit vent in January 2008; waveforms for Type 2 and 3 VLP events were similar although Type 3 were lower amplitude and shorter in duration. Weak infrasound records for Type 1 explosions compared to Type 2 suggest lower magma pressures and higher porosity for Type 1. Type 3 events correlate with spikes in SO2 emission rate and are driven by partial sealing and rapid release of ash-free gas at the summit vent. In 2012, both vents were active again and produced waveforms like those observed in earlier deployments. We also had a 9-station network of broadband stations that allow for improved waveform modeling. We suggest variations in the VLP period may provide a new tool for monitoring conditions within the conduit.xamples of VLP waveforms from Type 1 explosions (red, in a), Type 2 explosions (blue in b) and Type 3 puffing exhalations (black in c) and their spectra (d) highlight the waveform shape and frequency content of each. All data were deconvolved and filtered with the same 2-pole acausal Butterworth filter with corners at 60 and 12 seconds. In each of the plots, the fine lines are for individual events and the thick

  1. A biogeographic network reveals evolutionary links between deep-sea hydrothermal vent and methane seep faunas.

    PubMed

    Kiel, Steffen

    2016-12-14

    Deep-sea hydrothermal vents and methane seeps are inhabited by members of the same higher taxa but share few species, thus scientists have long sought habitats or regions of intermediate character that would facilitate connectivity among these habitats. Here, a network analysis of 79 vent, seep, and whale-fall communities with 121 genus-level taxa identified sedimented vents as a main intermediate link between the two types of ecosystems. Sedimented vents share hot, metal-rich fluids with mid-ocean ridge-type vents and soft sediment with seeps. Such sites are common along the active continental margins of the Pacific Ocean, facilitating connectivity among vent/seep faunas in this region. By contrast, sedimented vents are rare in the Atlantic Ocean, offering an explanation for the greater distinction between its vent and seep faunas compared with those of the Pacific Ocean. The distribution of subduction zones and associated back-arc basins, where sedimented vents are common, likely plays a major role in the evolutionary and biogeographic connectivity of vent and seep faunas. The hypothesis that decaying whale carcasses are dispersal stepping stones linking these environments is not supported.

  2. Degassing during magma ascent in the Mule Creek vent (USA)

    USGS Publications Warehouse

    Stasiuk, M.V.; Barclay, J.; Carroll, M.R.; Jaupart, Claude; Ratte, J.C.; Sparks, R.S.J.; Tait, S.R.

    1996-01-01

    The structures and textures of the rhyolite in the Mule Creek vent (New Mexico, USA) indicate mechanisms by which volatiles escape from silicic magma during eruption. The vent outcrop is a 300-m-high canyon wall comprising a section through the top of a feeder conduit, vent and the base of an extrusive lava dome. Field relations show that eruption began with an explosive phase and ended with lava extrusion. Analyses of glass inclusions in quartz phenocrysts from the lava indicate that the magma had a pre-eruptive dissolved water content of 2.5-3.0 wt% and, during eruption, the magma would have been water-saturated over the vertical extent of the present outcrop. However, the vesicularity of the rhyolite is substantially lower than that predicted from closed-system models of vesiculation under equilibrium conditions. At a given elevation in the vent, the volume fraction of primary vesicles in the rhyolite increases from zero close to the vent margin to values of 20-40 vol.% in the central part. In the centre the vesicularity increases upward from approximately 20 vol.% at 300 m below the canyon rim to approximately 40 vol.% at 200 m, above which it shows little increase. To account for the discrepancy between observed vesicularity and measured water content, we conclude that gas escaped during ascent, probably beginning at depths greater than exposed, by flow through the vesicular magma. Gas escape was most efficient near the vent margin, and we postulate that this is due both to the slow ascent of magma there, giving the most time for gas to escape, and to shear, favouring bubble coalescence. Such shear-related permeability in erupting magma is supported by the preserved distribution of textures and vesicularity in the rhyolite: Vesicles are flattened and overlapping near the dense margins and become progressively more isolated and less deformed toward the porous centre. Local zones have textures which suggest the coalescence of bubbles to form permeable

  3. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, James K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell.

  4. Modeling of zero gravity venting

    NASA Technical Reports Server (NTRS)

    Merte, H., Jr.

    1984-01-01

    The venting of cylindrical containers partially filled with initially saturated liquids was conducted under zero gravity conditions and compared with an analytical model which determined the effect of interfacial mass transfer on the ullage pressure response during venting. A model is proposed to improve the estimation of the interfacial mass transfer. Duhammel's superposition integral is incorporated in this analysis to approximate the transient temperature response of the interface, treating the liquid as a semiinfinite solid with conduction heat transfer. This approach to estimating interfacial mass transfer gives improved response when compared to previous models. The model still predicts a pressure decrease greater than those in the experiments reported.

  5. Development of an improved active gas target design for ANASEN

    NASA Astrophysics Data System (ADS)

    Schill, Sabina; Blackmon, J. C.; Deibel, C. M.; Macon, K. T.; Rasco, B. C.; Wiedenhoever, I.

    2014-09-01

    The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) is a charged particle detector array with an active gas target-detector capability for sensitive measurements using radioactive ion beams. One of the main goals is to improve our understanding of nuclear reactions important in stellar explosions. Following initial experimental campaigns with ANASEN, we have been developing an improved active gas target design for ANASEN that incorporates an innovative cylindrical gas ionization detector for heavy ions surrounding the beam axis inside of the other ANASEN charged particle detectors. The detection of heavy ions in coincidence with lighter ions in a redesigned proportional counter will provide greater discriminating power. The new active gas target design will be presented, and its simulated performance will be compared with test data. The Array for Nuclear Astrophysics and Structure with Exotic Nuclei (ANASEN) is a charged particle detector array with an active gas target-detector capability for sensitive measurements using radioactive ion beams. One of the main goals is to improve our understanding of nuclear reactions important in stellar explosions. Following initial experimental campaigns with ANASEN, we have been developing an improved active gas target design for ANASEN that incorporates an innovative cylindrical gas ionization detector for heavy ions surrounding the beam axis inside of the other ANASEN charged particle detectors. The detection of heavy ions in coincidence with lighter ions in a redesigned proportional counter will provide greater discriminating power. The new active gas target design will be presented, and its simulated performance will be compared with test data. This work was supported by the U.S. National Science Foundation and the Dept of Energy's Office of Science.

  6. Genomic Reconstruction of an Uncultured Hydrothermal Vent Gammaproteobacterial Methanotroph (Family Methylothermaceae) Indicates Multiple Adaptations to Oxygen Limitation

    PubMed Central

    Skennerton, Connor T.; Ward, Lewis M.; Michel, Alice; Metcalfe, Kyle; Valiente, Chanel; Mullin, Sean; Chan, Ken Y.; Gradinaru, Viviana; Orphan, Victoria J.

    2015-01-01

    Hydrothermal vents are an important contributor to marine biogeochemistry, producing large volumes of reduced fluids, gasses, and metals and housing unique, productive microbial and animal communities fueled by chemosynthesis. Methane is a common constituent of hydrothermal vent fluid and is frequently consumed at vent sites by methanotrophic bacteria that serve to control escape of this greenhouse gas into the atmosphere. Despite their ecological and geochemical importance, little is known about the ecophysiology of uncultured hydrothermal vent-associated methanotrophic bacteria. Using metagenomic binning techniques, we recovered and analyzed a near-complete genome from a novel gammaproteobacterial methanotroph (B42) associated with a white smoker chimney in the Southern Lau basin. B42 was the dominant methanotroph in the community, at ∼80x coverage, with only four others detected in the metagenome, all on low coverage contigs (7x–12x). Phylogenetic placement of B42 showed it is a member of the Methylothermaceae, a family currently represented by only one sequenced genome. Metabolic inferences based on the presence of known pathways in the genome showed that B42 possesses a branched respiratory chain with A- and B-family heme copper oxidases, cytochrome bd oxidase and a partial denitrification pathway. These genes could allow B42 to respire over a wide range of oxygen concentrations within the highly dynamic vent environment. Phylogenies of the denitrification genes revealed they are the result of separate horizontal gene transfer from other Proteobacteria and suggest that denitrification is a selective advantage in conditions where extremely low oxygen concentrations require all oxygen to be used for methane activation. PMID:26779119

  7. Genomic Reconstruction of an Uncultured Hydrothermal Vent Gammaproteobacterial Methanotroph (Family Methylothermaceae) Indicates Multiple Adaptations to Oxygen Limitation.

    PubMed

    Skennerton, Connor T; Ward, Lewis M; Michel, Alice; Metcalfe, Kyle; Valiente, Chanel; Mullin, Sean; Chan, Ken Y; Gradinaru, Viviana; Orphan, Victoria J

    2015-01-01

    Hydrothermal vents are an important contributor to marine biogeochemistry, producing large volumes of reduced fluids, gasses, and metals and housing unique, productive microbial and animal communities fueled by chemosynthesis. Methane is a common constituent of hydrothermal vent fluid and is frequently consumed at vent sites by methanotrophic bacteria that serve to control escape of this greenhouse gas into the atmosphere. Despite their ecological and geochemical importance, little is known about the ecophysiology of uncultured hydrothermal vent-associated methanotrophic bacteria. Using metagenomic binning techniques, we recovered and analyzed a near-complete genome from a novel gammaproteobacterial methanotroph (B42) associated with a white smoker chimney in the Southern Lau basin. B42 was the dominant methanotroph in the community, at ∼80x coverage, with only four others detected in the metagenome, all on low coverage contigs (7x-12x). Phylogenetic placement of B42 showed it is a member of the Methylothermaceae, a family currently represented by only one sequenced genome. Metabolic inferences based on the presence of known pathways in the genome showed that B42 possesses a branched respiratory chain with A- and B-family heme copper oxidases, cytochrome bd oxidase and a partial denitrification pathway. These genes could allow B42 to respire over a wide range of oxygen concentrations within the highly dynamic vent environment. Phylogenies of the denitrification genes revealed they are the result of separate horizontal gene transfer from other Proteobacteria and suggest that denitrification is a selective advantage in conditions where extremely low oxygen concentrations require all oxygen to be used for methane activation.

  8. Venting and High Vacuum Performance of Low Density Multilayer Insulation

    NASA Astrophysics Data System (ADS)

    Riesco, M. E.; McLean, C. H.; Mills, G. L.; Buerger, S.; Meyer, M. L.

    2010-04-01

    The NASA Exploration Program is currently studying the use liquid oxygen, liquid methane and liquid hydrogen for propulsion in future spacecraft for Exploration of the Moon and Mars. This will require the efficient long term, on-orbit storage of these cryogenic propellants. Multilayer Insulation (MLI) will be critical to achieving the required thermal performance since it has much lower heat transfer than any other insulation when used in a vacuum. MLI with a low density (⩽10 layers/cm) has been shown in previous work to be the most mass efficient. The size and mass constraints of these propulsion systems will not allow a structural shell to be used to provide vacuum for the MLI during ground hold and launch. The baseline approach is to purge the MLI during ground hold with an inert gas which is then vented during launch ascent and on-orbit. This paper presents the results on experimental tests and modeling performed by Ball Aerospace on low density, non-perforated MLI used to insulate a cryogenic tank simulating an Exploration cryogenic propellant storage vessel. These include measurements of the rate of venting and of the heat transfer of gas filled insulation, fully evacuated insulation and during the transition in between. Results of transient computer modeling of the MLI venting and heat transfer process are also presented. Previous work by some of the authors performed vent testing using MLI with perforations and slits and a slow pump down rate.

  9. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  10. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  11. 40 CFR 63.1275 - Glycol dehydration unit process vent standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... National Emission Standards for Hazardous Air Pollutants From Natural Gas Transmission and Storage... dehydration unit subject to this subpart with an actual annual average natural gas flowrate equal to or... connecting the process vent to a process natural gas line. (2) The owner or operator shall demonstrate,...

  12. DUCKS: Low cost thermal monitoring units for near-vent deployment

    USGS Publications Warehouse

    Harris, A.; Pirie, D.; Horton, K.; Garbeil, H.; Pilger, E.; Ramm, H.; Hoblitt, R.; Thornber, C.; Ripepe, M.; Marchetti, E.; Poggi, P.

    2005-01-01

    During 1999 we designed and tested a thermal monitoring system to provide a cheap, robust, modular, real-time system capable of surviving the hostile conditions encountered proximal to active volcanic vents. In November 2000 the first system was deployed at Pu'u 'O'o (Kilauea, Hawai'i) to target persistently active vents. Aside from some minor problems, such as sensor damage due to tampering, this system remained operational until January 2004. The success of the prototype system led us to use the blueprint for a second installation at Stromboli (Aeolian Islands, Italy). This was deployed, dug into a bomb-proof bunker, during May 2002 and survived the April 2003 paroxysmal eruption despite being located just 250 m from the vent. In both cases, careful waterproofing of connectors and selection of suitable protection has prevented water damage and corrosion in the harsh atmosphere encountered at the crater rim. The Pu'u 'O'o system cost ???US$10,000 and comprises four modules: sensors, transmission and power hub, repeater station and reception site. The sensor component consists of three thermal infrared thermometers housed in Pelican??? cases fitted with Germanium-Arsenide-Selenium windows. Two 1?? field of view (FOV) sensors allow specific vents to be targeted and a 60?? FOV sensor provides a crater floor overview. A hard wire connection links to a Pelican???-case-housed microprocessor, modem and power module. From here data are transmitted, via a repeater site, to a dedicated PC at the Hawaiian Volcano Observatory. Here data are displayed with a delay of ???3 s between acquisition and display. The modular design allows for great flexibility. At Stromboli, 1?? and 15?? FOV sensor modules can be switched depending changes in activity style and crater geometry. In addition a direct line of site to the Stromboli reception center negates the repeater site requirement, reducing the cost to US$5500 for a single sensor system. We have also constructed self-contained units

  13. DUCKS: Low cost thermal monitoring units for near-vent deployment

    NASA Astrophysics Data System (ADS)

    Harris, Andrew; Pirie, Dawn; Horton, Keith; Garbeil, Harold; Pilger, Eric; Ramm, Hans; Hoblitt, Rick; Thornber, Carl; Ripepe, Maurizio; Marchetti, Emanuele; Poggi, Pasquale

    2005-05-01

    During 1999 we designed and tested a thermal monitoring system to provide a cheap, robust, modular, real-time system capable of surviving the hostile conditions encountered proximal to active volcanic vents. In November 2000 the first system was deployed at Pu'u 'O'o (Kilauea, Hawai'i) to target persistently active vents. Aside from some minor problems, such as sensor damage due to tampering, this system remained operational until January 2004. The success of the prototype system led us to use the blueprint for a second installation at Stromboli (Aeolian Islands, Italy). This was deployed, dug into a bomb-proof bunker, during May 2002 and survived the April 2003 paroxysmal eruption despite being located just 250 m from the vent. In both cases, careful waterproofing of connectors and selection of suitable protection has prevented water damage and corrosion in the harsh atmosphere encountered at the crater rim. The Pu'u 'O'o system cost ˜US10,000 and comprises four modules: sensors, transmission and power hub, repeater station and reception site. The sensor component consists of three thermal infrared thermometers housed in Pelican™ cases fitted with Germanium-Arsenide-Selenium windows. Two 1° field of view (FOV) sensors allow specific vents to be targeted and a 60° FOV sensor provides a crater floor overview. A hard wire connection links to a Pelican™-case-housed microprocessor, modem and power module. From here data are transmitted, via a repeater site, to a dedicated PC at the Hawaiian Volcano Observatory. Here data are displayed with a delay of ˜3 s between acquisition and display. The modular design allows for great flexibility. At Stromboli, 1° and 15° FOV sensor modules can be switched depending changes in activity style and crater geometry. In addition a direct line of site to the Stromboli reception center negates the repeater site requirement, reducing the cost to US5500 for a single sensor system. We have also constructed self-contained units

  14. Fill and vent quick disconnect

    NASA Technical Reports Server (NTRS)

    Boerner, R. Y.; Hedrick, R. W.

    1972-01-01

    Hydraulic disconnect coupling on ground serving half of spacecraft refrigeration cooling system employs movable center stem for venting and closing nipple poppet. Self sealing poppet quickly connects cooling system to spacecraft without manual work. Recessed sealing surface insures open poppet when stem retracts.

  15. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Venting. 151.15-5 Section 151.15-5 Shipping COAST GUARD...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with...

  16. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  17. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  18. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  19. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  20. 33 CFR 159.61 - Vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Vents. 159.61 Section 159.61 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Design, Construction, and Testing § 159.61 Vents. Vents must be designed and...

  1. Time-lapse camera observations of gas piston activity at Pu‘u ‘Ō‘ō, Kīlauea volcano, Hawai‘i

    USGS Publications Warehouse

    Orr, Tim R.; Rea, James

    2012-01-01

    Gas pistoning is a type of eruptive behavior described first at Kīlauea volcano and characterized by the (commonly) cyclic rise and fall of the lava surface within a volcanic vent or lava lake. Though recognized for decades, its cause continues to be debated, and determining why and when it occurs has important implications for understanding vesiculation and outgassing processes at basaltic volcanoes. Here, we describe gas piston activity that occurred at the Pu‘u ‘Ō‘ō cone, in Kīlauea’s east rift zone, during June 2006. Direct, detailed measurements of lava level, made from time-lapse camera images captured at close range, show that the gas pistons during the study period lasted from 2 to 60 min, had volumes ranging from 14 to 104 m3, displayed a slowing rise rate of the lava surface, and had an average gas release duration of 49 s. Our data are inconsistent with gas pistoning models that invoke gas slug rise or a dynamic pressure balance but are compatible with models which appeal to gas accumulation and loss near the top of the lava column, possibly through the generation and collapse of a foam layer.

  2. Types and Evolution of Gas Hydrate System along the Tectonically Active Zones of the Western Pacific: Nankai Trough vs. Eastern Margin of Japan Sea

    NASA Astrophysics Data System (ADS)

    Matsumoto, R.; Tomaru, H.; Takeuchi, L.; Hiruta, A.; Ishizaki, O.; Aoyama, C.; Machiyama, H.; Goto, T.

    2007-12-01

    are widely distributed throughout the area, while no double BSRs are observed. BSRs within gas chimneys are very strong and often exhibit pull-up structure. A number of piston corers have recovered chunks of massive gas hydrate from the mounds. ROV dives observed gas hydrates exposed atop the mounds. Furthermore, electric ocean floor survey has revealed that sediments below the pockmark-mound zones were not conductive. These lines of evidence suggest that the mounds are more-or-less composed of or at least contain significant amounts of methane. Sea-level fall during the last glacial, 120 m in Japan Sea, should have caused instability of gas hydrate, in particular, those within pockmarks. Pull-up structures within the chimney seem to support the model that the mounds are gas hydrate dome and the pockmark, probably a relic hydrate mound. Glacial sea level fall should have caused massive dissociation of subsurface methane hydrate as in case of the Nankai trough. However the methane from the dissociation of massive hydrate in the chimney should escape to seawater to form a crater-like depression pockmarks. Considering active venting, gigantic plumes, inferred violent venting and perhaps floating of massive gas hydrates, gas hydrate deposits are to be formed during warmer, high-sea level periods, and episodic dissociation and massive emission of methane to ocean/atmosphere system.

  3. The influence of vent fluid chemistry on trophic structure at two deep-sea hydrothermal vent fields on the Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    Bennett, Sarah; Van Dover, Cindy; Coleman, Max

    2014-05-01

    The two known deep-sea hydrothermal vent fields along the Mid-Cayman Rise are separated by a distance of only 21 km, yet their chemistry and faunal diversity are distinct. The deeper of the two vent fields, Piccard (with active venting from Beebe Vents, Beebe Woods and Beebe Sea), at 4980 m is basalt hosted. The shallower vent field, Von Damm, at 2300 m appears to have an ultramafic influence. The Von Damm vent field can be separated into two sites: The Spire and The Tubeworm Field. The dominant vent fluids at the Tubeworm Field are distinct from those at the Spire, as a result of fluid modification in the sub-surface. Von Damm and Piccard vent fields support abundant invertebrates, sharing the same biomass-dominant shrimp species, Rimicaris hybisae. Although there are some other shared species (squat lobsters (Munidopsis sp.) and gastropods (Provanna sp. and Iheyaspira sp.)) between the vent fields, they are much more abundant at one site than the other. In this study we have examined the bulk carbon, nitrogen and sulfur isotope composition of microbes and fauna at each vent field. With these data we have deduced the trophic structure of the communities and the influence of vent fluid chemistry. From stable isotope data and end-member vent fluid chemistry, we infer that the basis of the trophic structure at Piccard is dominated by sulfur, iron, and hydrogen-oxidizing microbial communities. In comparison, the basis of the Von Damm trophic structure is dominated by microbial communities of sulfur and hydrogen oxidizers, sulfate reducers and methanotrophs. This microbial diversity at the base of the trophic structure is a result of chemical variations in vent fluids and processes in the sub-surface that alter the vent fluid chemistry. These differences influence higher trophic levels and can be used to explain some of the variability as well as similarity in fauna at the vent sites. Part of this work was performed at the Jet Propulsion Laboratory, California

  4. Hydrothermal Fluxes at the Turtle Pits Vent Site, southern MAR

    NASA Astrophysics Data System (ADS)

    Köhler, J.; Walter, M.; Mertens, C.; Sültenfuß, J.; Rhein, M.

    2009-04-01

    The Turtle Pits vent fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5oS. The site consists of three known hydrothermal fields: Turtle Pits, Comfortless Cove, and Red Lion. Data collected during a Meteor cruise in May 2006 and a L' Atalante cruise in January 2008 are used to calculate the total emission of volume, heat, and helium of the site. The data sets consist of vertical profiles and towed transsects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. Vent fluid samples for noble gas analysis where taken with an ROV. The particle plume is confined to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the helium fluxes at the vent sites in comparison with the horizontal helium transport in the valley. The comparison of the 3He concentration measured south of the hydrothermal vents with the 3He signal north of the hydrothermal vents suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and an average 3He end member concentration a flux of 900 l/s is estimated, which corresponds to a heat flux of 450 MW. The rise height of the particle plume estimated from the turbidity data combined with the known background stratification yields an estimate of the total flux of the hydrothermal vents which is one order of magnitude lower.

  5. Gas and Chemical Activation of Charcoal

    DTIC Science & Technology

    1945-06-29

    supplemented ’ by runs in the laboratory has shown that zinc chloride is by far the most suitable activating agent. 1. In the dehydration mixing of...istics with time of dehydration . 3. The physical appearance of the mixture during the impregnation pperation provides sufficient significant information...to enable the operator to predict .mechanical characteristics of the briquet. CONFIDENTIAL " • ’< i£: • CONFIDENTIAL -4- 4* In the dehydration

  6. 77 FR 58616 - Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-21

    ... Safety: Information Collection Activities, Revision to Gas Transmission and Gathering Pipeline Systems... TRANSPORTATION Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering Pipeline Systems Annual Report, Gas Transmission...

  7. Recent Investigation of In-Situ pH in Hydrothermal Vent Fluids at Main Endeavour Field (MEF) and ASHES Vent Field (ASHES): Implications for Dynamic Changes in Subseafloor Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Ding, K.; Seyfried, W. E., Jr.; Tan, C.; Schaen, A. T.; Luhmann, A. J.

    2014-12-01

    In-situ pH is among the key factors affecting chemical reactions involved with fluid-rock interaction and metal transport in hydrothermal systems. A small variation in pH will often result in a large difference in dissolved metal concentrations. For instance, at 400oC, a decrease of ~0.15 pH unit will cause dissolved Fe concentration to double in fluid coexisting with a Fe-bearing mineral assemblage. This parameter also offers us an opportunity to better understand processes controlling the temporal evolution of hydrothermal vent fluid chemistry at mid-ocean ridges. During our recent cruise AT 26-17 with newly upgraded DSV2 Alvin, in-situ measurements of pH were carried out along with gas-tight sampling of vent fluids. Our efforts were focused at MEF and ASHES on the Juan de Fuca Ridge. These hydrothermal systems have been shown to be particularly responsive to subseafloor seismic and magmatic events. The measured fluid temperature was approximately 333˚C and 300˚C at Dante vent orifice of MEF and Inferno vent orifice of ASHES, respectively. The corresponding measured in-situ pH values for both vents are: 4.94 and 4.88, respectively. Dissolved gases and other species were also measured from gas-tight fluid samples providing a means of comparison with the in-situ data. As we have known the earthquake and magmatic activity often places the system at higher temperature and more reducing conditions in connection with a new evolutionary cycle. Comparing these relatively low in-situ pH values with those measured in the past, especially with the ones obtained at MEF in 1999 after an intense swarm of earthquakes, we see the system trending towards more acidic conditions along with decreasing temperature and dissolved H2 and H2S. Taking an example from Dante vent site, in-situ pH value of 5.15 was recorded with a measured temperature of 363oC two month after the event in 1999, which gives 0.2 pH unit greater than the more recent data. Measured dissolved H2 and H2S

  8. Deep-sea hydrothermal vents: potential hot spots for natural products discovery?

    PubMed

    Thornburg, Christopher C; Zabriskie, T Mark; McPhail, Kerry L

    2010-03-26

    Deep-sea hydrothermal vents are among the most extreme and dynamic environments on Earth. However, islands of highly dense and biologically diverse communities exist in the immediate vicinity of hydrothermal vent flows, in stark contrast to the surrounding bare seafloor. These communities comprise organisms with distinct metabolisms based on chemosynthesis and growth rates comparable to those from shallow water tropical environments, which have been rich sources of biologically active natural products. The geological setting and geochemical nature of deep-sea vents that impact the biogeography of vent organisms, chemosynthesis, and the known biological and metabolic diversity of Eukarya, Bacteria, and Archaea, including the handful of natural products isolated to date from deep-sea vent organisms, are considered here in an assessment of deep-sea hydrothermal vents as potential hot spots for natural products investigations. Of critical importance too are the logistics of collecting deep vent organisms, opportunities for re-collection considering the stability and longevity of vent sites, and the ability to culture natural product-producing deep vent organisms in the laboratory. New cost-effective technologies in deep-sea research and more advanced molecular techniques aimed at screening a more inclusive genetic assembly are poised to accelerate natural product discoveries from these microbial diversity hot spots.

  9. Detection of diffuse sea floor venting using structured light imaging

    NASA Astrophysics Data System (ADS)

    Inglis, G.; Smart, C.; Roman, C.; Carey, S.

    2011-12-01

    Efficiently identifying and localizing diffuse sea floor venting at hydrothermal and cold seep sites is often difficult. Actively venting fluids are usually identified by a temperature induced optical shimmering seen during direct visual inspections or in video data collected by vehicles working close to the sea floor. Relying on such direct methods complicates establishing spatial relations between areas within a survey covering a broad area. Our recent work with a structured light laser system has shown that venting can also be detected in the image data in an automated fashion. A structured light laser system consists of a camera and sheet laser projected at the sea floor. The camera and laser are fixed to a rigid calibrated mount such that the optical axis of the camera and the laser plane intersect at some distance away from the camera, typically 2 to 5 meters. The position of the laser line, visible on the sea floor in the image, can be extracted using standard computer vision techniques (Fig. 1) and used to determine the height of the bottom along the laser line. By collecting images in a survey pattern at a high frame rate, typically 20 to 30 Hz, a bathymetric map can be produced using the individual profiles. In the presence of venting, temperature anomalies refract the laser sheet such that it does not project a crisp and clear line on the sea floor. The laser will instead appear blurred and visible over a larger section of the image. By processing the images to segment out clear laser lines from refracted lines it is possible to identify areas of venting. Our initial approach uses calculated image moments relative to the peak intensity level detected in each column of the image matrix. In the presence of venting the calculated moments differ from those of the undistorted laser shining on the sea floor. Test results from the Kolumbo submarine volcano near Santorini, Greece demonstrate this approach and show the utility of the method for survey work. Test

  10. A Mouthful of Dirt: Feedbacks Between the Presence and Nature of In-Vent Debris and the Dynamics of Strombolian Explosions

    NASA Astrophysics Data System (ADS)

    Taddeucci, J.; Capponi, A.; Scarlato, P.; Palladino, D. M.

    2015-12-01

    Textural, modelling and observational evidences indicate the presence of loose to molten debris capping the magma column in the conduit of Strombolian-type volcanoes. This debris is thought to have a role in controlling the release of gas during one explosion and the amount and grain size of the eruption products. Here we report direct observations on the behaviour of debris covering the eruptive vents during Strombolian explosions at Stromboli volcano, Italy. During several field campaigns from 2008 onwards, the eruptive vents were in direct view from our observation point, and volcanic activity was recorded using a variety of video equipment, including high-speed and thermal cameras. Debris-covered vents were observed in several cases. In such cases the explosion was preceded by the gradual, time-exponential bulging of the debris cover, followed, in some cases, by a deflation and in-vent collapse of the debris. The amount and grain size distribution of the debris control the eruptive behaviour. Often, blocks and lapilli may not be entirely removed by explosions, which may occur through the debris and around the larger blocks. In such cases the explosions tend to erupt relatively cold (non-plastic) bombs and lapilli, and minor amounts of ash. Finer-grained debris covers are entirely removed by explosions, and can be entrained in the explosions and collapse separately to form small pyroclastic density currents. The ensuing explosions are invariably ash-rich. Both fine and coarse debris is observed to fall back in the vent after each explosion but also to gravitationally accumulate in between the explosions from the seep crater flanks. In contrast, open-vent eruptions tend to erupt hotter (plastically deforming) pyroclasts at a higher exit velocity.

  11. Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent…

  12. Microdistribution of Faunal Assemblages at Deep-Sea Hydrothermal Vents in the Southern Ocean

    PubMed Central

    Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Linse, Katrin; Reid, William D. K.; Rogers, Alex D.; Sweeting, Christopher J.; Tyler, Paul A.

    2012-01-01

    Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m2 of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m−2), followed by a peltospiroid gastropod (>1,500 individuals m−2), eolepadid barnacle (>1,500 individuals m−2), and carnivorous actinostolid anemone (>30 individuals m−2). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in δ34S values of primary consumers with distance from vent sources, and variation in their δ13C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies

  13. Microdistribution of faunal assemblages at deep-sea hydrothermal vents in the Southern Ocean.

    PubMed

    Marsh, Leigh; Copley, Jonathan T; Huvenne, Veerle A I; Linse, Katrin; Reid, William D K; Rogers, Alex D; Sweeting, Christopher J; Tyler, Paul A

    2012-01-01

    Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and hydrothermal activity in a vent field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of hydrothermal activity, and a mosaic image of >250 m(2) of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from vent sources and peak temperatures. Assemblages closest to vent sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m(-2)), followed by a peltospiroid gastropod (>1,500 individuals m(-2)), eolepadid barnacle (>1,500 individuals m(-2)), and carnivorous actinostolid anemone (>30 individuals m(-2)). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for vent fauna in this new biogeographic province. An increase in δ(34)S values of primary consumers with distance from vent sources, and variation in their δ(13)C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent environment over a greater extent than previous studies

  14. A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents

    USGS Publications Warehouse

    Reysenbach, A.-L.; Liu, Yajing; Banta, A.B.; Beveridge, T.J.; Kirshtein, J.D.; Schouten, S.; Tivey, M.K.; Von Damm, Karen L.; Voytek, M.A.

    2006-01-01

    Deep-sea hydrothermal vents are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced hydrothermal fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively venting sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from vent deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal vent euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75??C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea vents. ?? 2006 Nature Publishing Group.

  15. Phenomenology of a Water Venting in Low Earth Orbit

    DTIC Science & Technology

    1992-01-01

    the three electronic cameras, typical views aerochemical and dynamical effects (6], and con- of the particle clouds from which are reproduced in...same initial flow bursts), so that the initial expansion of this vapor is conditions as in space shuttle’s now-routine vent- collisional . This gas then... simulation chamber [91 Nb. The to%%ard the particle trail (refer to Table I and centing nozzle is about 5 m from the nearest segment of the Fig. 2(a

  16. Environmental & Water Quality Operational Studies: Improvement of Hydropower Release Dissolved Oxygen with Turbine Venting.

    DTIC Science & Technology

    1987-03-01

    provides air to 13 the turbine is long, with bends, elbows, and valves which cause a significant loss of energy as air flows through the venting...large air flow rate (Figures B28-B29). The turbine efficiency losses and gas transfer were generally greater with deflectors than without. 74. Based on...provide a data base to develop predictive and design capabilities for turbine venting systems.’ tesultsoft these tests>indicated that, at most, the oxygen

  17. Reactor pressure vessel vented head

    DOEpatents

    Sawabe, J.K.

    1994-01-11

    A head for closing a nuclear reactor pressure vessel shell includes an arcuate dome having an integral head flange which includes a mating surface for sealingly mating with the shell upon assembly therewith. The head flange includes an internal passage extending therethrough with a first port being disposed on the head mating surface. A vent line includes a proximal end disposed in flow communication with the head internal passage, and a distal end disposed in flow communication with the inside of the dome for channeling a fluid therethrough. The vent line is fixedly joined to the dome and is carried therewith when the head is assembled to and disassembled from the shell. 6 figures.

  18. Ephemerality of discrete methane vents in lake sediments

    USGS Publications Warehouse

    Scandella, Benjamin P.; Pillsbury, Liam; Weber, Thomas; Ruppel, Carolyn D.; Hemond, Harold F.; Juanes, Ruben

    2016-01-01

    Methane is a potent greenhouse gas whose emission from sediments in inland waters and shallow oceans may both contribute to global warming and be exacerbated by it. The fraction of methane emitted by sediments that bypasses dissolution in the water column and reaches the atmosphere as bubbles depends on the mode and spatiotemporal characteristics of venting from the sediments. Earlier studies have concluded that hot spots—persistent, high-flux vents—dominate the regional ebullitive flux from submerged sediments. Here the spatial structure, persistence, and variability in the intensity of methane venting are analyzed using a high-resolution multibeam sonar record acquired at the bottom of a lake during multiple deployments over a 9 month period. We confirm that ebullition is strongly episodic, with distinct regimes of high flux and low flux largely controlled by changes in hydrostatic pressure. Our analysis shows that the spatial pattern of ebullition becomes homogeneous at the sonar's resolution over time scales of hours (for high-flux periods) or days (for low-flux periods), demonstrating that vents are ephemeral rather than persistent, and suggesting that long-term, lake-wide ebullition dynamics may be modeled without resolving the fine-scale spatial structure of venting.

  19. Ephemerality of discrete methane vents in lake sediments

    NASA Astrophysics Data System (ADS)

    Scandella, Benjamin P.; Pillsbury, Liam; Weber, Thomas; Ruppel, Carolyn; Hemond, Harold F.; Juanes, Ruben

    2016-05-01

    Methane is a potent greenhouse gas whose emission from sediments in inland waters and shallow oceans may both contribute to global warming and be exacerbated by it. The fraction of methane emitted by sediments that bypasses dissolution in the water column and reaches the atmosphere as bubbles depends on the mode and spatiotemporal characteristics of venting from the sediments. Earlier studies have concluded that hot spots—persistent, high-flux vents—dominate the regional ebullitive flux from submerged sediments. Here the spatial structure, persistence, and variability in the intensity of methane venting are analyzed using a high-resolution multibeam sonar record acquired at the bottom of a lake during multiple deployments over a 9 month period. We confirm that ebullition is strongly episodic, with distinct regimes of high flux and low flux largely controlled by changes in hydrostatic pressure. Our analysis shows that the spatial pattern of ebullition becomes homogeneous at the sonar's resolution over time scales of hours (for high-flux periods) or days (for low-flux periods), demonstrating that vents are ephemeral rather than persistent, and suggesting that long-term, lake-wide ebullition dynamics may be modeled without resolving the fine-scale spatial structure of venting.

  20. Heat and Volume Fluxes at the Turtle Pits Vent Site, southern Mid Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Köhler, Janna; Walter, Maren; Mertens, Christian; Sültenfuß, Jürgen; Rhein, Monika

    2010-05-01

    The Turtle Pits vent site consists of eight known high temperature vents and several diffuse vent sites which are distributed over three hydrothermal fields: Turtle Pits, Comfortless Cove, and Red Lion. These vent fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5°S. The total volume and heat emissions of the entire Turtle Pits site have been calculated with three different approaches using data collected during a Meteor cruise in May 2006 and a L'Atalante cruise in January 2008. The data sets consist of vertical profiles and towed transects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. Vent fluid samples for noble gas analysis where taken with ROVs. Since the vent fluid is highly enriched in primordial 3He this noble gas can be used as a conservative tracer for vent fluid. The geographical setting of the vent site confines the particle plume to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the horizontal helium transport in the valley in combination with a mean 3He endmember concentration determined from the water samples taken with the ROVs. The comparison of the 3He concentrations measured south of the hydrothermal vents with the 3He signal north of the hydrothermal vents suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and the average 3He endmember concentration a flux of 1000 l/s is estimated, which corresponds to a heat flux of 1400 MW. The measured temperature anomalies within the plume combined with the known

  1. Evidence for a chemoautotrophically based food web at inactive hydrothermal vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Erickson, K. L.; Macko, S. A.; Van Dover, C. L.

    2009-09-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where hydrothermally active and inactive sites are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive sites. Carbon and nitrogen isotopic compositions of animals occupying inactive sites are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive sites, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  2. Evidence for a Chemoautotrophically Based Food Web at Inactive Hydrothermal Vents (Manus Basin)

    NASA Astrophysics Data System (ADS)

    van Dover, C. L.; Erickson, K.; Macko, S.

    2008-12-01

    Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

  3. Filtered-vented containment systems. [PWR; BWR

    SciTech Connect

    Benjamin, A S; Walling, H C; Cybulskis, P; DiSalvo, R

    1980-01-01

    The potential benefits of filtered-vented containment systems as a means for mitigating the effects of severe accidents are analyzed. Studies so far have focused upon two operating reactor plants in the United States, a large-containment pressurized water reactor and a Mark I containment boiling water reactor. Design options that could be retrofitted to these plants are described including single-component once-through venting systems, multiple-component systems with vent and recirculation capabilities, and totally contained venting systems. A variety of venting strategies are also described which include simple low-volume containment pressure relief strategies and more complicated, high-volume venting strategies that require anticipatory actions. The latter type of strategy is intended for accidents that produce containment-threatening pressure spikes.

  4. Short- and Long-Term Dynamics of Gas Hydrate at GC600: A Gulf of Mexico Hydrocarbon Seep

    NASA Astrophysics Data System (ADS)

    MacDonald, I. R.; Johansen, C.; Silva, M.; Daneshgar, S.; Garcia-Pineda, O. G.; Shedd, W. W.

    2014-12-01

    The GC600 hydrocarbon seep is located at 1200 m in the northern Gulf of Mexico (GOM). Satellite data show it to be one of the most prolific sources of natural oil slicks in the entire GOM. We mapped its seafloor oil and gas vents with 3-D seismic, swath-bathymetry acoustics and submersible observations, documenting gas hydrate deposits, brine pools, benthic fauna, and authigenic carbonates. Geophysical profiles show subbottom locations of salt bodies and migration conduits. We deployed time-lapse imaging systems focused on individual vents to quantify release rates. Oil and gas flow upward along the flanks of an allochthonous salt body from source rocks at 10,000 m and migrate to the seafloor from faults emanating from the salt. Venting to the water column and surface consists of oily bubbles and occurs in two fields separated by ~1 km. The NW vent field (Megaplume) appears to be a more recent expression and hosts about three highly active vents; while the SE vent field (Birthday Candles) hosts more than 10 vents that are generally slower. We measured discharge rates of 2.6 cm3 s-1 and Megaplume and 0.09 cm3 s-1 at Birthday Candles. Although surface deposits of gas hydrate were evident at both vent fields, the Birthday Candles area featured dozens of conical mounds formed by gas hydrate that were dark brown due to large amounts of liquid oil perfused throughout the deposits. Large brine pools indicated gas hydrate formation at the seafloor. Venting occurred in horizontal fissures on the mounds, in which oil and hydrate combined to form short-lived chimneys and balloon-like structures. Ice worms (Hesiocaeca methanicola) were extremely abundant in burrows extending from the sediment into the gas hydrate. Proceeding farther to the SE, venting is reduced and absent, but surface carbonate deposits suggest relict gas hydrate mounds. We propose that the NW to SE trend at GC600 encompasses the progressive development of a biogeochemical filter that sequesters and

  5. Grain-based activated carbons for natural gas storage.

    PubMed

    Zhang, Tengyan; Walawender, Walter P; Fan, L T

    2010-03-01

    Natural gas has emerged as a potential alternative to gasoline due to the increase in global energy demand and environmental concerns. An investigation was undertaken to explore the technical feasibility of implementing the adsorbed natural gas (ANG) storage in the fuel tanks of motor vehicles with activated carbons from biomass, e.g., sorghum and wheat. The grain-based activated carbons were prepared by chemical activation; the experimental parameters were varied to identify the optimum conditions. The porosity of the resultant activated carbons was evaluated through nitrogen adsorption; and the storage capacity, through methane adsorption. A comparative study was also carried out with commercial activated carbons from charcoal. The highest storage factor attained was 89 for compacted grain-based activated carbons from grain sorghum with a bulk density of 0.65 g/cm(3), and the highest storage factor attained is 106 for compacted commercial activated carbons (Calgon) with a bulk density of 0.70 g/cm(3). The storage factor was found to increase approximately linearly with increasing bulk density and to be independent of the extent of compaction. This implies that the grain-based activated carbons are the ideal candidates for the ANG storage.

  6. Relationships between lava types, seafloor morphology, and the occurrence of hydrothermal venting in the ASHES vent field of Axial Volcano. [Axial Seamount Hydrothermal Emission Study

    SciTech Connect

    Hammond, S.R. )

    1990-08-10

    Deep-towed and submersible photographic surveys within the caldera of Axial Volcano have been integrated with high-resolution bathmetry to produce a geological map of the most active vent field in the caldera. Locations for over 2,000 photographs in and near the vent field were determined using a seafloor transponder network. Then each photograph was described utilizing a classification system which provides detailed information concerning lava type, hydrothermal activity, sediment cover, geological structure, and biology. Resulting data were entered into a digital data base, and computer-generated maps were created that portray spatial relationships between selected geological variables. In general, the entire ASHES field is characterized by pervasive low-temperature venting. The most vigorous venting is concentrated in an approximately 80 m {times} 80 m area where there are several high-temperature vents including some which are producing high-temperature vapor-phase fluids derived from a boiling hydrothermal system. Lava types within the ASHES vent field are grouped into three distinct morphologies: (1) smooth (flat-surfaced, ropy, and whorled) sheet flows, (2) lobate flows, and (3) jumbled-sheet flows. The most intense hydrothermal venting is concentrated in the smooth sheet flows and the lobate flows. The location of the ASHES field is mainly attributable to faulting which defines the southwest caldera wall, but the concentration of intense venting appears to be related also to the spatial distribution of lava types in the vent field and their contrasting permeabilities. Other structural trends of faults and fissures within the field also influence the location of individual events.

  7. Evaluation of aperture cover tank vent nozzles for the IRAS spacecraft

    NASA Technical Reports Server (NTRS)

    Richter, R.

    1983-01-01

    The influence of coefficients for the three axes of the Infrared Astronomical Satellite (IRAS) were established to determine the maximum allowable thrust difference between the two vent nozzles of the aperture cover tank low thrust vent system and their maximum misalignment. Test data generated by flow and torque measurements permitted the selection of two nozzles whose thrust differential was within the limit of the attitude control capability. Based on thrust stand data, a thrust vector misalignment was indicated that was slightly higher than permissible for the worst case, i.e., considerable degradation of the torque capacity of the attitude control system combined with venting of helium at its upper limit. The probability of destabilizing the IRAS spacecraft by activating the venting system appeared to be very low. The selection and mounting of the nozzles have satisfied all the requirements for the safe venting of helium.

  8. Discovery of abundant hydrothermal venting on the ultraslow-spreading Gakkel ridge in the Arctic Ocean.

    PubMed

    Edmonds, H N; Michael, P J; Baker, E T; Connelly, D P; Snow, J E; Langmuir, C H; Dick, H J B; Mühe, R; German, C R; Graham, D W

    2003-01-16

    Submarine hydrothermal venting along mid-ocean ridges is an important contributor to ridge thermal structure, and the global distribution of such vents has implications for heat and mass fluxes from the Earth's crust and mantle and for the biogeography of vent-endemic organisms. Previous studies have predicted that the incidence of hydrothermal venting would be extremely low on ultraslow-spreading ridges (ridges with full spreading rates <2 cm x yr(-1)-which make up 25 per cent of the global ridge length), and that such vent systems would be hosted in ultramafic in addition to volcanic rocks. Here we present evidence for active hydrothermal venting on the Gakkel ridge, which is the slowest spreading (0.6-1.3 cm x yr(-1)) and least explored mid-ocean ridge. On the basis of water column profiles of light scattering, temperature and manganese concentration along 1,100 km of the rift valley, we identify hydrothermal plumes dispersing from at least nine to twelve discrete vent sites. Our discovery of such abundant venting, and its apparent localization near volcanic centres, requires a reassessment of the geologic conditions that control hydrothermal circulation on ultraslow-spreading ridges.

  9. Explosive Volcanic Eruptions from Linear Vents on Earth, Venus and Mars: Comparisons with Circular Vent Eruptions

    NASA Technical Reports Server (NTRS)

    Glaze, Lori S.; Baloga, Stephen M.; Wimert, Jesse

    2010-01-01

    Conditions required to support buoyant convective plumes are investigated for explosive volcanic eruptions from circular and linear vents on Earth, Venus, and Mars. Vent geometry (linear versus circular) plays a significant role in the ability of an explosive eruption to sustain a buoyant plume. On Earth, linear and circular vent eruptions are both capable of driving buoyant plumes to equivalent maximum rise heights, however, linear vent plumes are more sensitive to vent size. For analogous mass eruption rates, linear vent plumes surpass circular vent plumes in entrainment efficiency approximately when L(sub o) > 3r(sub o) owing to the larger entrainment area relative to the control volume. Relative to circular vents, linear vents on Venus favor column collapse and the formation of pyroclastic flows because the range of conditions required to establish and sustain buoyancy is narrow. When buoyancy can be sustained, however, maximum plume heights exceed those from circular vents. For current atmospheric conditions on Mars, linear vent eruptions are capable of injecting volcanic material slightly higher than analogous circular vent eruptions. However, both geometries are more likely to produce pyroclastic fountains, as opposed to convective plumes, owing to the low density atmosphere. Due to the atmospheric density profile and water content on Earth, explosive eruptions enjoy favorable conditions for producing sustained buoyant columns, while pyroclastic flows would be relatively more prevalent on Venus and Mars. These results have implications for the injection and dispersal of particulates into the planetary atmosphere and the ability to interpret the geologic record of planetary volcanism.

  10. Reactor pressure vessel head vents and methods of using the same

    SciTech Connect

    Gels, John L; Keck, David J; Deaver, Gerald A

    2014-10-28

    Internal head vents are usable in nuclear reactors and include piping inside of the reactor pressure vessel with a vent in the reactor upper head. Piping extends downward from the upper head and passes outside of the reactor to permit the gas to escape or be forcibly vented outside of the reactor without external piping on the upper head. The piping may include upper and lowers section that removably mate where the upper head joins to the reactor pressure vessel. The removable mating may include a compressible bellows and corresponding funnel. The piping is fabricated of nuclear-reactor-safe materials, including carbon steel, stainless steel, and/or a Ni--Cr--Fe alloy. Methods install an internal head vent in a nuclear reactor by securing piping to an internal surface of an upper head of the nuclear reactor and/or securing piping to an internal surface of a reactor pressure vessel.

  11. Tidal influence on gas bubble emissions from permanent seafloor observations at Ocean Networks Canada's cabled array NEPTUNE

    NASA Astrophysics Data System (ADS)

    Roemer, M.; Scherwath, M.; Heesemann, M.; Spence, G.; Riedel, M.

    2015-12-01

    Sonar data from the northern Cascadia margin correlate well with tidal pressure changes and not so well with currents, seafloor shaking from storms or earthquakes, or temperature changes. These data are available from Ocean Networks Canada which operates the NEPTUNE observatory with power and communications to gas hydrate sites on the continental slope, allowing 24/7 monitoring of the dynamic gas hydrate activity. Clayoquot Slope at Cascadia's Bullseye Vent and Bubbly Gulch, is equipped with a variety of sensors including a 270 kHz Imagenex 100 m range multibeam sonar, as well as Conductivity-Temperature-Depth (CTD) sensors, high precision Bottom Pressure Recorders (BPR), current meter and Ocean Bottom Seismograph (OBS). This enables statistically meaningful correlation of these data. Hourly sonar data were collected showing venting activity in the form of gas plumes of various strengths. For four years the sonar was located at what appears to be a transient gas site, with longer periods of absolutely no venting observed activity. Here, the strongest correlation of gas bubbling is with rapid decreasing tidal pressure, where subsequent increasing tidal pressure is shutting down the degassing. In May 2014, the sonar was moved by 500 m to a more actively venting site termed Gastown Alley, over a zone of seismic blanking interpreted as having high subsurface gas content. This site is continuously emitting gas bubbles albeit with varying numbers of plumes and intensities. The strongest correlation of gas discharge is with absolute pressures, with maximum flows at higher tidal pressures, hinting at a steady subsurface rise of gas that is squeezed out stronger at high tides, partially emptying the shallow reservoirs, and with subsiding tidal pressure the venting activity also decreases again. Thus, the two sonar sites, though only 500 m apart, show a different behavior in degassing, however, both reacting most strongly to tidal pressure changes.

  12. Development of a passive self-cleaning scrubber for containment venting applications

    SciTech Connect

    Owen, R.K.; Postma, A.K.

    1980-04-01

    A novel air cleaning concept is being developed for potential use in venting reactor containment buildings. The two-stage system employs a pre-scrubber (a submerged gravel scrubber) and a fibrous scrubber to obtain high removal efficiencies for particulate contaminants. The submerged gravel scrubber is unique in that water flow is induced by the gas flow, eliminating the need for an active liquid pump. In addition, design gas velocities through the gravel bed are 10 to 20 times higher than for a conventional sand bed filter. A series of development tests have been performed on an engineering scale model with a gravel bed area of 0.07 m/sup 2/. Hydraulic tests indicate that the scrubber can be designed to operate at a superficial gas velocity of 0.50 m/s. Aerosol tests were performed with a variety of sodium fire aerosols. The aerosol mass removal efficiency for the pre-scrubber was 99.8% and the efficiency for the system exceeded 99.99%. The test results show that the aerosol removal efficiency is not a strong function of the gas velocity. Scale-up tests were made to evaluate gas distribution on a larger bed. The results demonstrated that the self-cleaning gravel bed can be scaled-up to the sizes required for full-scale containment applications.

  13. Active Combustion Control for Aircraft Gas Turbine Engines

    NASA Technical Reports Server (NTRS)

    DeLaat, John C.; Breisacher, Kevin J.; Saus, Joseph R.; Paxson, Daniel E.

    2000-01-01

    Lean-burning combustors are susceptible to combustion instabilities. Additionally, due to non-uniformities in the fuel-air mixing and in the combustion process, there typically exist hot areas in the combustor exit plane. These hot areas limit the operating temperature at the turbine inlet and thus constrain performance and efficiency. Finally, it is necessary to optimize the fuel-air ratio and flame temperature throughout the combustor to minimize the production of pollutants. In recent years, there has been considerable activity addressing Active Combustion Control. NASA Glenn Research Center's Active Combustion Control Technology effort aims to demonstrate active control in a realistic environment relevant to aircraft engines. Analysis and experiments are tied to aircraft gas turbine combustors. Considerable progress has been shown in demonstrating technologies for Combustion Instability Control, Pattern Factor Control, and Emissions Minimizing Control. Future plans are to advance the maturity of active combustion control technology to eventual demonstration in an engine environment.

  14. 4D seismic study of active gas seepage systems on the Vestnesa Ridge, offshore W-Svalbard

    NASA Astrophysics Data System (ADS)

    Bünz, Stefan; Plaza-Faverola, Andreia; Hurter, Sandra; Mienert, Jürgen

    2014-05-01

    Active gas venting occurs on the Vestnesa Ridge, an elongated sediment drift north of the Molloy Transform and just east of the Molloy Ridge, one of the shortest segments of the slow spreading North-Atlantic Ridge system. The crest of the Vestnesa Ridge at water depth between 1200-1300 m is pierced with fluid-flow features. Seafloor pockmarks vary in size up to 1 km in diameter. High-resolution P-Cable 3D seismic data acquired in 2012 show vertical focused fluid flow features beneath the seafloor pockmarks. These co-called chimneys extend down to the free-gas zone underneath a bottom-simulating reflection. Here, they link up with small fault systems that might provide pathways to the deeper subsurface. The chimney features show a high variability in their acoustic characteristics with alternating blanked or masked zones and high-amplitude anomalies scattered through the whole vertical extent of the chimneys. The amplitude anomalies indicate high-impedance contrasts due to the likely presence of gas or a high-velocity material like gas hydrates or carbonates. We re-acquired the 3D seismic survey in 2013 for time-lapse seismic studies in order to better understand the origin of the amplitude anomalies and in order to track potentially migrating gas fronts up along the chimney structure. Here, we will present the preliminary results of this time-lapse analysis, which will allow us to better understand gas migration and seafloor plumbing systems in continental margins. This work is part of CAGE - Centre of Excellence for Arctic Gas Hydrate, Environment and Climate. Details on the CAGE research plan and organization can be found on www.cage.uit.no to foster opportunities for cross-disciplinary collaboration. Based in Tromsø, at the world's northernmost University, CAGE establishes the intellectual and infrastructure resources for studying the amount of methane hydrate and magnitude of methane release in Arctic Ocean environments on time scales from the Neogene to the

  15. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...: (1) An integral vent system listed or certified as part of the appliance. (2) A venting system... roof line or outside the wall line may be installed at the site. Sectional venting systems shall...

  16. Decline of a Hydrothermal Vent Field - Escanaba Trough 12 Years Later

    NASA Astrophysics Data System (ADS)

    Zierenberg, R. A.; Clague, D. A.; Davis, A. S.; Lilley, M. D.; McClain, J. S.; Olson, E. S.; Ross, S. L.; Von Damm, K. L.

    2001-12-01

    Hydrothermal venting was discovered in Escanaba Trough, the southern sediment-covered portion of the Gorda Ridge, in 1988. Large pyrrhotite-rich massive sulfide mounds are abundant at each of the volcanic/intrusive centers that have been investigated in Escanaba Trough, but the only area of known hydrothermal venting is the NESCA site along the ridge axis at 41\\deg N. Hydrothermal fluids venting at 217\\deg C and 108\\deg C were sampled in 1988 on two sulfide mounds separated by about 275 m. The end-member fluid compositions were indistinguishable within analytical errors. Several sulfide mounds were observed in 1988 which had diffusely venting low temperature (< 20\\deg C) fluids that supported extensive vent communities dominated by fields of Ridgia. Nine holes were drilled in the NESCA area in 1996 on ODP Leg 169, including Hole 1036I that penetrated to basaltic basement at 405 m below sea floor (mbsf). Surveys of the area using the drill string camera located only one area of active venting at the same mound where 217\\deg C vent fluids were sampled from two active vents in 1988. Drill hole 1036A was spudded between the two active vents on this sulfide mound (approximately 4 and 8 m away) and penetrated to 115 mbsf. The NESCA site was revisited in 2000 using MBARI's R/V Western Flyer and ROV Tiburon. The hydrothermal vents appeared essentially identical to observations made from the drill string camera in 1996 despite the presence of a drill hole within meters of the two vents. The maximum vent temperature measured in 2000 was 212\\deg C. Fluid samples have major element and isotopic compositions very similar to those collected in 1988. The vent fluids have higher methane ( ~19 mmol/kg) than those from the geologically similar Middle Valley vent field, but lower values than those at Guaymas Basin. Drill hole 1036A was weakly venting, but the diffuse hydrothermal fluids could not be sampled with the equipment available. The walls of the drill hole were

  17. 46 CFR 151.15-5 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Pressure-vacuum venting. A normally closed venting system fitted with a device to automatically limit the pressure or vacuum in the tank to design limits. Pressure-vacuum relief valves shall comply with the... devices in accordance with the requirements of § 54.15-13 of this chapter. (2) When a...

  18. Dust and ionized gas in active radio elliptical galaxies

    NASA Technical Reports Server (NTRS)

    Forbes, D. A.; Sparks, W. B.; Macchetto, F. D.

    1990-01-01

    The authors present broad and narrow bandwidth imaging of three southern elliptical galaxies which have flat-spectrum active radio cores (NGC 1052, IC 1459 and NGC 6958). All three contain dust and extended low excitation optical line emission, particularly extensive in the case of NGC 1052 which has a large H alpha + (NII) luminosity. Both NGC 1052 and IC 1459 have a spiral morphology in emission-line images. All three display independent strong evidence that a merger or infall event has recently occurred, i.e., extensive and infalling HI gas in NGC 1052, a counter-rotating core in IC 1459 and Malin-Carter shells in NGC 6958. This infall event is the most likely origin for the emission-line gas and dust, and the authors are currently investigating possible excitation mechanisms (Sparks et al. 1990).

  19. Vent Field Distribution and Evolution Along the Endeavour Segment, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Kelley, D. S.; Delaney, J. R.; Lilley, M. D.; Butterfield, D. A.

    2001-12-01

    Five major vent fields have now been discovered along the Endeavour Segment of the Juan de Fuca Ridge. From the north to the south they include Sasquatch, Salty Dawg, High Rise, Main Endeavour, and Mothra. Spacing between the distinct, high-temperature fields increases from the north to the south. For example Sasquatch is located 1.6 km north of Salty Dawg and Mothra is 2.7 km south of the Main Endeavour Field. In addition to changes in spacing of the vent fields along axis there are also dramatic changes in the style, intensity, and thermal-chemical characteristics of venting. The newly discovered Sasquatch field extends for >200 m in length, and venting is limited to a few isolated, small structures that reach 284° C. Active venting is confined to the northern portion of the field. In contrast, extinct, massive sulfide edifices and oxidized sulfide talus can be followed continuously for over 200 m along a 25-30 m wide, 020 trending ridge indicating that this field was very active in the past. In contrast to the delicate active structures, older extinct structures reach at least 25 m in height and the aspect ratios are similar to active pillars in the Mothra Field 7.5 km, to the south. It is unclear if venting at this site represents rejuvenation of the field, or whether it is in a waning stage. Within Salty Dawg, vent fluid temperatures reach 296° C and vigorous venting is constrained to a few, multi-flanged edifices that reach 25 m in height and 25 m in length. The field hosts over 25 structures, oxidized sulfide is abundant, and diffuse flow is dominant. Fluid compositions and temperatures are consistent with Salty Dawg being in a waning stage of evolution. Venting intensity and incidence of venting increase dramatically at High Rise where numerous multi-flanged structures are active; temperatures reach 343° C. The most intense and active of the fields is the Main Endeavour, with at least 21 actively venting, multi-flanged edifices that contain at least 100

  20. Hydrothermal Vents in Yellowstone Lake: Chemical Fluxes, Siliceous Deposits, and Collapse Structures

    NASA Astrophysics Data System (ADS)

    Shanks, W. P.; Morgan, L. A.; Balistrieri, L.; Alt, J.; Meeker, G.

    2002-12-01

    The geochemistry of Yellowstone Lake is strongly influenced by sublacustrine hydrothermal vent activity. The hydrothermal source fluid is identified using Cl and dD data on water column and sublacustrine hydrothermal vent fluid samples. Silica-rich hydrothermal deposits occur on the lake bottom near active and presently inactive hydrothermal vents. Pipe- and flange-like deposits contain cemented and recrystallized diatoms and represent pathways for hydrothermal fluid migration. Another major type of hydrothermal deposit comprises hard, porous siliceous spires up to 7 m tall that occur in 15 m of water in Bridge Bay. Bridge Bay spires are hydrothermal silica deposits formed in place by growth of chimney-like features from lake-bottom hydrothermal vents. The Cl concentrations indicate that Yellowstone Lake water is about 1 percent hydrothermal source fluid and 99 percent inflowing stream water and that the flux is about 10 percent of the total hydrothermal water flux in Yellowstone National Park. With recent swath-sonar mapping studies that show numerous new hydrothermal features, Yellowstone Lake should now be considered one of the most significant hydrothermal basins in the Park. Many lake-bottom hydrothermal vents occur in small depressions that are clearly imaged on multibeam sonar, some of which are interpreted as collapse structures based on seismic reflection data. Sediments collected from such vents show chemical evidence of leaching of 60-70 wt. percent SiO2, which may result in volume reductions up to 80 percent and provides a mechanism for vent structure formation.

  1. Testing of an Ammonia EVA Vent Tool for the International Space Station

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Stanewich, Brett J.; Wilhelm, Sheri Munekata

    2000-01-01

    When components of the International Space Station ammonia External Active Thermal Control System are replaced on-orbit, they must be vented immediately after removal from the system. Venting ensures that the component is not hard packed with liquid and thus does not pose a hazard. An extravehicular activity (EVA) vent tool has been developed to perform this function. However, there were concerns that the tool could whip, posing a hazard to the EVA astronaut, or would freeze. The ammonia vent tool was recently tested in a thermal/vacuum chamber to demonstrate that it would operate safely and would not freeze during venting. During the test, ammonia mimicking the venting conditions for six different heat exchanger initial conditions was passed through representative test articles. In the present work, the model that was used to develop the ammonia state and flow for the test points is discussed and the test setup and operation is described. The qualitative whipping and freezing results of the test are discussed and vent plume pressure measurements are described and interpreted.

  2. Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse hydrothermal vent fluids

    PubMed Central

    Akerman, Nancy H.; Butterfield, David A.; Huber, Julie A.

    2013-01-01

    Microorganisms throughout the dark ocean use reduced sulfur compounds for chemolithoautotrophy. In many deep-sea hydrothermal vents, sulfide oxidation is quantitatively the most important chemical energy source for microbial metabolism both at and beneath the seafloor. In this study, the presence and activity of vent endemic Epsilonproteobacteria was examined in six low-temperature diffuse vents over a range of geochemical gradients from Axial Seamount, a deep-sea volcano in the Northeast Pacific. PCR primers were developed and applied to target the sulfur oxidation soxB gene of Epsilonproteobacteria. soxB genes belonging to the genera Sulfurimonas and Sulfurovum are both present and expressed at most diffuse vent sites, but not in background seawater. Although Sulfurovum-like soxB genes were detected in all fluid samples, the RNA profiles were nearly identical among the vents and suggest that Sulfurimonas-like species are the primary Epsilonproteobacteria responsible for actively oxidizing sulfur via the Sox pathway at each vent. Community patterns of subseafloor Epsilonproteobacteria 16S rRNA genes were best matched to methane concentrations in vent fluids, as well as individual vent locations, indicating that both geochemistry and geographical isolation play a role in structuring subseafloor microbial populations. The data show that in the subseafloor at Axial Seamount, Epsilonproteobacteria are expressing the soxB gene and that microbial patterns in community distribution are linked to both vent location and chemistry. PMID:23847608

  3. Subtidal gastropods consume sulfur-oxidizing bacteria: evidence from coastal hydrothermal vents

    SciTech Connect

    Stein, J.L.

    1984-02-17

    The black abalone (Haliotis cracherodii), a commercially important shallow-water gastropod common off White Point, Southern California, is found frequently at subtidal hydrothermal vents within mats of filamentous sulfur-oxidizing bacteria. Foraging vent abalones actively consume the bacteria and confine their nightly feeding forays to bacterial mats surrounding the vents. The growth of abalones consuming the sulfur bacteria exceeds that of control individuals consuming microalgae and is comparable to reported growth rates of abalones consuming macroalgae. Thus, off White Point, the black abalone may derive a portion of its nutrition from the subsidy of geothermal energy.

  4. Explosion testing for the container venting system

    SciTech Connect

    Cashdollar, K.L.; Green, G.M.; Thomas, R.A.; Demiter, J.A.

    1993-09-30

    As part of the study of the hazards of inspecting nuclear waste stored at the Hanford Site, the US Department of Energy and Westinghouse Hanford Company have developed a container venting system to sample the gases that may be present in various metal drums and other containers. In support of this work, the US Bureau of Mines has studied the probability of ignition while drilling into drums and other containers that may contain flammable gas mixtures. The Westinghouse Hanford Company drilling procedure was simulated by tests conducted in the Bureau`s 8-liter chamber, using the same type of pneumatic drill that will be used at the Hanford Site. There were no ignitions of near-stoichiometric hydrogen-air or methane-air mixtures during the drilling tests. The temperatures of the drill bits and lids were measured by an infrared video camera during the drilling tests. These measured temperatures are significantly lower than the {approximately}500{degree}C autoignition temperature of uniformly heated hydrogen-air or the {approximately}600{degree}C autoignition temperature of uniformly heated methane-air. The temperatures are substantially lower than the 750{degree}C ignition temperature of hydrogen-air and 1,220{degree}C temperature of methane-air when heated by a 1-m-diameter wire.

  5. Natural gas storage with activated carbon from a bituminous coal

    USGS Publications Warehouse

    Sun, Jielun; Rood, M.J.; Rostam-Abadi, M.; Lizzio, A.A.

    1996-01-01

    Granular activated carbons ( -20 + 100 mesh; 0.149-0.84 mm) were produced by physical activation and chemical activation with KOH from an Illinois bituminous coal (IBC-106) for natural gas storage. The products were characterized by BET surface area, micropore volume, bulk density, and methane adsorption capacities. Volumetric methane adsorption capacities (Vm/Vs) of some of the granular carbons produced by physical activation are about 70 cm3/cm3 which is comparable to that of BPL, a commercial activated carbon. Vm/Vs values above 100 cm3/cm3 are obtainable by grinding the granular products to - 325 mesh (<0.044 mm). The increase in Vm/Vs is due to the increase in bulk density of the carbons. Volumetric methane adsorption capacity increases with increasing pore surface area and micropore volume when normalizing with respect to sample bulk volume. Compared with steam-activated carbons, granular carbons produced by KOH activation have higher micropore volume and higher methane adsorption capacities (g/g). Their volumetric methane adsorption capacities are lower due to their lower bulk densities. Copyright ?? 1996 Elsevier Science Ltd.

  6. Optical Breath Gas Sensor for Extravehicular Activity Application

    NASA Technical Reports Server (NTRS)

    Wood, William R.; Casias, Miguel E.; Vakhtin, Andrei B.; Pilgrim, Jeffrey S.; Chullen, Cinda; Falconi, Eric A.; McMillin, Summer

    2013-01-01

    The function of the infrared gas transducer used during extravehicular activity in the current space suit is to measure and report the concentration of carbon dioxide (CO2) in the ventilation loop. The next generation portable life support system (PLSS) requires next generation CO2 sensing technology with performance beyond that presently in use on the Space Shuttle/International Space Station extravehicular mobility unit (EMU). Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. A laser diode spectrometer based on wavelength modulation spectroscopy is being developed for this purpose by Vista Photonics, Inc. Two prototype devices were delivered to NASA Johnson Space Center (JSC) in September 2011. The sensors incorporate a laser diode-based CO2 channel that also includes an incidental water vapor (humidity) measurement and a separate oxygen channel using a vertical cavity surface emitting laser. Both prototypes are controlled digitally with a field-programmable gate array/microcontroller architecture. The present development extends and upgrades the earlier hardware to the Advanced PLSS 2.0 test article being constructed and tested at JSC. Various improvements to the electronics and gas sampling are being advanced by this project. The combination of low power electronics with the performance of a long wavelength laser spectrometer enables multi-gas sensors with significantly increased performance over that presently offered in the EMU.

  7. Selection and preparation of activated carbon for fuel gas storage

    DOEpatents

    Schwarz, James A.; Noh, Joong S.; Agarwal, Rajiv K.

    1990-10-02

    Increasing the surface acidity of active carbons can lead to an increase in capacity for hydrogen adsorption. Increasing the surface basicity can facilitate methane adsorption. The treatment of carbons is most effective when the carbon source material is selected to have a low ash content i.e., below about 3%, and where the ash consists predominantly of alkali metals alkali earth, with only minimal amounts of transition metals and silicon. The carbon is washed in water or acid and then oxidized, e.g. in a stream of oxygen and an inert gas at an elevated temperature.

  8. San Diego Gas and Electric Company Imperial Valley geothermal activities

    NASA Technical Reports Server (NTRS)

    Hinrichs, T. C.

    1974-01-01

    San Diego Gas and Electric and its wholly owned subsidiary New Albion Resources Co. have been affiliated with Magma Power Company, Magma Energy Inc. and Chevron Oil Company for the last 2-1/2 years in carrying out geothermal research and development in the private lands of the Imperial Valley. The steps undertaken in the program are reviewed and the sequence that must be considered by companies considering geothermal research and development is emphasized. Activities at the south end of the Salton Sea and in the Heber area of Imperial Valley are leading toward development of demonstration facilities within the near future. The current status of the project is reported.

  9. International oil and gas exploration and development activities

    SciTech Connect

    Not Available

    1990-10-29

    This report is part of an ongoing series of quarterly publications that monitors discoveries of oil and natural gas in foreign countries and provides an analysis of the reserve additions that result. The report is prepared by the Energy Information Administration (EIA) of the US Department of Energy (DOE) under the Foreign Energy Supply Assessment Program (FESAP). It presents a summary of discoveries and reserve additions that result from recent international exploration and development activities. It is intended for use by petroleum industry analysts, various government agencies, and political leaders in the development, implementation, and evaluation of energy plans, policy, and legislation. 25 refs., 8 figs., 4 tabs.

  10. Emissions of volatile organic compounds (VOCs) from oil and natural gas activities: compositional comparison of 13 major shale basins via NOAA airborne measurements

    NASA Astrophysics Data System (ADS)

    Gilman, J.; Lerner, B. M.; Aikin, K. C.; De Gouw, J. A.; Koss, A.; Yuan, B.; Warneke, C.; Peischl, J.; Ryerson, T. B.; Holloway, J. S.; Graus, M.; Tokarek, T. W.; Isaacman-VanWertz, G. A.; Sueper, D.; Worsnop, D. R.

    2015-12-01

    The recent and unprecedented increase in natural gas production from shale formations is associated with a rise in the production of non-methane volatile organic compounds (VOCs) including natural gas plant liquids (e.g., ethane, propane, and butanes) and liquid lease condensate (e.g., pentanes, hexanes, aromatics and cycloalkanes). Since 2010, the production of natural gas liquids and the amount of natural gas vented/flared has increased by factors of ~1.28 and 1.57, respectively (U.S. Energy and Information Administration), indicating an increasingly large potential source of hydrocarbons to the atmosphere. Emission of VOCs may affect local and regional air quality due to the potential to form tropospheric ozone and organic particles as well as from the release of toxic species such as benzene and toluene. The 2015 Shale Oil and Natural Gas Nexus (SONGNex) campaign studied emissions from oil and natural gas activities across the central United States in order to better understand their potential air quality and climate impacts. Here we present VOC measurements from 19 research flights aboard the NOAA WP-3D over 11 shale basins across 8 states. Non-methane hydrocarbons were measured using an improved whole air sampler (iWAS) with post-flight analysis via a custom-built gas chromatograph-mass spectrometer (GC-MS). The whole air samples are complimented by higher-time resolution measurements of methane (Picarro spectrometer), ethane (Aerodyne spectrometer), and VOCs (H3O+ chemical ionization mass spectrometer). Preliminary analysis show that the Permian Basin on the New Mexico/Texas border had the highest observed VOC mixing ratios for all basins studied. We will utilize VOC enhancement ratios to compare the composition of methane and VOC emissions for each basin and the associated reactivities of these gases with the hydroxyl radical, OH, as a proxy for potential ozone formation.

  11. Endemicity of the cosmopolitan mesophilic chemolithoautotroph Sulfurimonas at deep-sea hydrothermal vents.

    PubMed

    Mino, Sayaka; Nakagawa, Satoshi; Makita, Hiroko; Toki, Tomohiro; Miyazaki, Junichi; Sievert, Stefan M; Polz, Martin F; Inagaki, Fumio; Godfroy, Anne; Kato, Shingo; Watanabe, Hiromi; Nunoura, Takuro; Nakamura, Koichi; Imachi, Hiroyuki; Watsuji, Tomo-O; Kojima, Shigeaki; Takai, Ken; Sawabe, Tomoo

    2017-04-01

    Rich animal and microbial communities have been found at deep-sea hydrothermal vents. Although the biogeography of vent macrofauna is well understood, the corresponding knowledge about vent microbial biogeography is lacking. Here, we apply the multilocus sequence analysis (MLSA) to assess the genetic variation of 109 Sulfurimonas strains with ⩾98% 16S rRNA gene sequence similarity, which were isolated from four different geographical regions (Okinawa Trough (OT), Mariana Volcanic Arc and Trough (MVAT), Central Indian Ridge (CIR) and Mid-Atlantic Ridge (MAR)). Sequence typing based on 11 protein-coding genes revealed high genetic variation, including some allele types that are widespread within regions, resulting in 102 nucleotide sequence types (STs). This genetic variation was predominantly due to mutation rather than recombination. Phylogenetic analysis of the 11 concatenated genes showed a clear geographical isolation corresponding to the hydrothermal regions they originated from, suggesting limited dispersal. Genetic differentiation among Sulfurimonas populations was primarily influenced by geographical distance rather than gas composition of vent fluid or habitat, although in situ environmental conditions of each microhabitat could not be examined. Nevertheless, Sulfurimonas may possess a higher dispersal capability compared with deep-sea hydrothermal vent thermophiles. This is the first report on MLSA of deep-sea hydrothermal vent Epsilonproteobacteria, which is indicative of allopatric speciation.

  12. Quantifying volcanic hazard at Campi Flegrei caldera (Italy) with uncertainty assessment: 1. Vent opening maps

    NASA Astrophysics Data System (ADS)

    Bevilacqua, Andrea; Isaia, Roberto; Neri, Augusto; Vitale, Stefano; Aspinall, Willy P.; Bisson, Marina; Flandoli, Franco; Baxter, Peter J.; Bertagnini, Antonella; Esposti Ongaro, Tomaso; Iannuzzi, Enrico; Pistolesi, Marco; Rosi, Mauro

    2015-04-01

    Campi Flegrei is an active volcanic area situated in the Campanian Plain (Italy) and dominated by a resurgent caldera. The great majority of past eruptions have been explosive, variable in magnitude, intensity, and in their vent locations. In this hazard assessment study we present a probabilistic analysis using a variety of volcanological data sets to map the background spatial probability of vent opening conditional on the occurrence of an event in the foreseeable future. The analysis focuses on the reconstruction of the location of past eruptive vents in the last 15 ka, including the distribution of faults and surface fractures as being representative of areas of crustal weakness. One of our key objectives was to incorporate some of the main sources of epistemic uncertainty about the volcanic system through a structured expert elicitation, thereby quantifying uncertainties for certain important model parameters and allowing outcomes from different expert weighting models to be evaluated. Results indicate that past vent locations are the most informative factors governing the probabilities of vent opening, followed by the locations of faults and then fractures. Our vent opening probability maps highlight the presence of a sizeable region in the central eastern part of the caldera where the likelihood of new vent opening per kilometer squared is about 6 times higher than the baseline value for the whole caldera. While these probability values have substantial uncertainties associated with them, our findings provide a rational basis for hazard mapping of the next eruption at Campi Flegrei caldera.

  13. Isolated communities of Epsilonproteobacteria in hydrothermal vent fluids of the Mariana Arc seamounts.

    PubMed

    Huber, Julie A; Cantin, Holly V; Huse, Susan M; Welch, David B Mark; Sogin, Mitchell L; Butterfield, David A

    2010-09-01

    Low-temperature hydrothermal vent fluids represent access points to diverse microbial communities living in oceanic crust. This study examined the distribution, relative abundance, and diversity of Epsilonproteobacteria in 14 low-temperature vent fluids from five volcanically active seamounts of the Mariana Arc using a 454 tag sequencing approach. Most vent fluids were enriched in cell concentrations compared with background seawater, and quantitative PCR results indicated that all fluids were dominated by bacteria. Operational taxonomic unit-based statistical tools applied to 454 data show that all vents from the northern end of the Mariana Arc grouped together, to the exclusion of southern arc seamounts, which were as distinct from one another as they were from northern seamounts. Statistical analysis also showed a significant relationship between seamount and individual vent groupings, suggesting that community membership may be linked to geographical isolation and not geochemical parameters. However, while there may be large-scale geographic differences, distance is not the distinguishing factor in the microbial community composition. At the local scale, most vents host a distinct population of Epsilonproteobacteria, regardless of seamount location. This suggests that there may be barriers to exchange and dispersal for these vent endemic microorganisms at hydrothermal seamounts of the Mariana Arc.

  14. Genetic diversity and connectivity of deep-sea hydrothermal vent metapopulations.

    PubMed

    Vrijenhoek, Robert C

    2010-10-01

    Deep-sea hydrothermal vents provide ephemeral habitats for animal communities that depend on chemosynthetic primary production. Sporadic volcanic and tectonic events destroy local vent fields and create new ones. Ongoing dispersal and cycles of extirpation and colonization affect the levels and distribution of genetic diversity in vent metapopulations. Several species exhibit evidence for stepping-stone dispersal along relatively linear, oceanic, ridge axes. Other species exhibit very high rates of gene flow, although natural barriers associated with variation in depth, deep-ocean currents, and lateral offsets of ridge axes often subdivide populations. Various degrees of impedance to dispersal across such boundaries are products of species-specific life histories and behaviours. Though unrelated to the size of a species range, levels of genetic diversity appear to correspond with the number of active vent localities that a species occupies within its range. Pioneer species that rapidly colonize nascent vents tend to be less subdivided and more diverse genetically than species that are slow to establish colonies at vents. Understanding the diversity and connectivity of vent metapopulations provides essential information for designing deep-sea preserves in regions that are under consideration for submarine mining of precious metals.

  15. 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...

  16. Geological and hydrothermal controls on the distribution of megafauna in Ashes Vent Field, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Arquit, Anne M.

    1990-08-01

    A computerized data base was constructed to aid in the interpretation of biological and geological observations recorded from 7662 photographs taken of Ashes vent field (located along the SW wall of the summit caldera of Axial Volcano, Juan de Fuca Ridge) during 1985-1986 using the Pisces IV submersible and a towed camera system. The transition region between the locus of high-temperature vents in Ashes vent field (i.e., Inferno, 326°C; Hell, 301°C; and Virgin Mound, 298°C) and more typical environmental conditions for the summit caldera of Axial Volcano as a whole is zoned spatially with respect to sediment type and organism assemblage. Three general ecological zones are identified within the vent field: (1) the central vent zone (within 100 m of a high-temperature vent), dominated by vent-associated organisms (vestimentiferan tube worms, clams, bacterial mats) and sedimentation (high-temperature, plume-derived and low-temperature, in situ deposits); (2) the distal vent zone (100-725 m from any high-temperature vent), characterized by extensive fields of iron oxide, iron silicate and silica chimneys and sediment (nontronite assemblage material), as well as maximum densities of most nonvent fauna; and (3) the nonvent impact zone (725-1300 m), indicated by elevated densities of nonvent organisms relative to regional (i.e., caldera-wide) values and maximum Bathydorus sp. sponge densities. The distribution of vestimentiferan tube worms is limited to within 90 m of known high-temperature venting (central vent zone); and anemones were observed only between 30 and 40 m from hot vents. Clams and microbial mats are concentrated in the central vent zone, as well, but occur sporadically up to 1250 m from the hot vents in association with hydrothermal nontronite that is probably precipitating in situ from <60°C vent fluid; thus megafaunal distributions are a useful indicator of poorly defined, often diffuse low-temperature hydrothermal activity on the seafloor. Maximum

  17. Design and integrated operation of an innovative thermodynamic vent system concept

    NASA Technical Reports Server (NTRS)

    Fazah, Michel M.; Lak, Tibor; Nguyen, Han; Wood, Charles C.

    1993-01-01

    A unique zero-g thermodynamic vent system (TVS) is being developed by NASA's Marshall Space Flight Center (MSFC) and Rockwell International to meet cryogenic propellant management requirements for future space missions. The design is highly innovative in that it integrates the functions of a spray-bar tank mixer and a TVS. This concept not only satisfies the requirement for efficient tank mixing and zero-g venting but also accommodates thermal conditioning requirements for other components (e.g., engine feed lines, turbopumps, and liquid acquisition devices). In addition, operations can be extended to accomplish tank chill-down, no-vent fill, and emergency venting during zero-g propellant transfer. This paper describes the system performance characterization and future test activities that are part of MSFC's Multipurpose Hydrogen Test Bed (MHTB) program. The testing will demonstrate the feasibility and merit of the design, and serve as a proof-of-concept development activity.

  18. Venting of Pressure through Perforated Plates

    DTIC Science & Technology

    1978-09-01

    2623, May 1976. (AD #BO11616L) 4. W.A. Keenan and J.A. Tamareto, "Blaat Envirowaent from Fully and Partially Vented Exploaions in Cubicles". Civil...the scatter of experimental results obtained from vented structures and high explosives. In Reference 4, Keenan and Tamareto developed an equation to...May 1976. (AD #BO11616L) 4. W.A. Keenan and J.A. Tamareto, "Blast Environment from l’ullyand Partially Vented Explosions in Cubicles". Civil

  19. Monitoring arrangement for vented nuclear fuel elements

    DOEpatents

    Campana, Robert J.

    1981-01-01

    In a nuclear fuel reactor core, fuel elements are arranged in a closely packed hexagonal configuration, each fuel element having diametrically opposed vents permitting 180.degree. rotation of the fuel elements to counteract bowing. A grid plate engages the fuel elements and forms passages for communicating sets of three, four or six individual vents with respective monitor lines in order to communicate vented radioactive gases from the fuel elements to suitable monitor means in a manner readily permitting detection of leakage in individual fuel elements.

  20. On the global distribution of hydrothermal vent fields: One decade later

    NASA Astrophysics Data System (ADS)

    Beaulieu, S. E.; Baker, E. T.; German, C. R.

    2012-12-01

    Since the last global compilation one decade ago, the known number of active submarine hydrothermal vent fields has almost doubled. At the end of 2009, a total of 518 active vent fields was catalogued, with about half (245) visually confirmed and others (273) inferred active at the seafloor. About half (52%) of these vent fields are at mid-ocean ridges (MORs), 25% at volcanic arcs, 21% at back-arc spreading centers (BASCs), and 2% at intra-plate volcanoes and other settings. One third are in high seas, and the nations with the most known active vent fields within EEZs are Tonga, USA, Japan, and New Zealand. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal deposits as mineral resources. Here, we have comprehensively documented the percentage of strike length at MORs and BASCs that has been systematically explored for hydrothermal activity. As of the end of 2009, almost 30% of the ~60,000 km of MORs had been surveyed at least with spaced vertical profiles to detect hydrothermal plumes. A majority of the vents discovered at MORs in the past decade occurred at segments with < 60 mm/yr full spreading rate. Discoveries at ultra-slow MORs in the past decade included the deepest known vent (Beebe at Mid-Cayman Rise) and high-temperature black smoker vents (e.g., Dragon at SWIR and Loki's Castle at Mohns Ridge), and the highest temperature vent was measured at the slow-spreading S MAR (Turtle Pits). Using a previously published equation for the linear relationship between the number of active vent fields per 100 km strike length (F_s) vs. weighted-average full spreading rate (u_s), we predicted 676 vent fields remaining to be discovered at MORs. Even accounting for the lower F_s at slower spreading rates, almost half of the vents that are predicted remaining to be discovered at MORs are at ultra-slow to slow spreading rates (< 40 mm/yr) and about 1/3 at intermediate rates (40-80 mm

  1. Assessing Radium Activity in Shale Gas Produced Brine

    NASA Astrophysics Data System (ADS)

    Fan, W.; Hayes, K. F.; Ellis, B. R.

    2015-12-01

    The high volumes and salinity associated with shale gas produced water can make finding suitable storage or disposal options a challenge, especially when deep well brine disposal or recycling for additional well completions is not an option. In such cases, recovery of commodity salts from the high total dissolved solids (TDS) of the brine wastewater may be desirable, yet the elevated concentrations of the naturally occurring radionuclides such as Ra-226 and Ra-228 in produced waters (sometimes substantially greater than the EPA limit of 5 pCi/L) may concentrate during these steps and limit salt recovery options. Therefore, assessing the potential presence of these Ra radionuclides in produced water from shale gas reservoir properties is desirable. In this study, we seek to link U and Th content within a given shale reservoir to the expected Ra content of produced brine by accounting for secular equilibrium within the rock and subsequent release to Ra to native brines. Produced brine from a series of Antrim shale wells and flowback from a single Utica-Collingwood shale well in Michigan were sampled and analyzed via ICP-MS to measure Ra content. Gamma spectroscopy was used to verify the robustness of this new Ra analytical method. Ra concentrations were observed to be up to an order of magnitude higher in the Antrim flowback water samples compared to those collected from the Utica-Collingwood well. The higher Ra content in Antrim produced brines correlates well with higher U content in the Antrim (19 ppm) relative to the Utica-Collingwood (3.5 ppm). We also observed an increase in Ra activity with increasing TDS in the Antrim samples. This Ra-TDS relationship demonstrates the influence of competing divalent cations in controlling Ra mobility in these clay-rich reservoirs. In addition, we will present a survey of geochemical data from other shale gas plays in the U.S. correlating shale U, Th content with produced brine Ra content. A goal of this study is to develop a

  2. 30 CFR 77.304 - Explosion release vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Explosion release vents. 77.304 Section 77.304... Dryers § 77.304 Explosion release vents. Drying chambers, dry-dust collectors, ductwork connecting dryers... explosion release vents which open directly to the outside atmosphere, and all such vents shall be:...

  3. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection...

  4. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection...

  5. 46 CFR 153.358 - Venting system flow capacity.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Venting Systems § 153.358 Venting system flow capacity. (a) The cross-sectional flow area of any vent system segment, including any PV or SR valve, must at no point be less than that of a pipe whose inside... 46 Shipping 5 2011-10-01 2011-10-01 false Venting system flow capacity. 153.358 Section...

  6. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  7. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... appliance listing and the appliance manufacturer's instructions. (b) Venting and combustion air...

  8. Modeling the Effects of Spacecraft Venting on Instrument Measurements of the Martian Atmosphere for an Elliptical Orbit

    NASA Technical Reports Server (NTRS)

    Petro, Elaine; Hughes, David

    2011-01-01

    Analysis has been performed for MAVEN mission. Due to the elliptical orbit, large pressure variations in orbit will be experienced, there is a need to understand how internal pressures change and the flux of gas from vents could potentially bias instrument measurements. Goal of this analysis is to predict the effect that atmospheric gases trapped and vented from spacecraft volumes could have on instrument measurements.

  9. Optical Breath Gas Sensor for Extravehicular Activity Application

    NASA Technical Reports Server (NTRS)

    Wood, William R.; Casias, Miguel E.; Vakhtin, Andrei B.; Pilgrim, Jeffrey S> ; Chullen, Cinda; Falconi, Eric A.

    2012-01-01

    The function of the infrared gas transducer used during extravehicular activity (EVA) in the current space suit is to measure and report the concentration of carbon dioxide (CO2) in the ventilation loop. The next generation Portable Life Support System (PLSS) requires next generation CO2 sensing technology with performance beyond that presently in use on the Shuttle/International Space Station extravehicular mobility unit (EMU). Accommodation within space suits demands that optical sensors meet stringent size, weight, and power requirements. A laser diode (LD) spectrometer based on wavelength modulation spectroscopy (WMS) is being developed for this purpose by Vista Photonics, Inc. Two prototype devices were delivered to NASA Johnson Space Center (JSC) in September 2011. The sensors incorporate a laser diode based CO2 channel that also includes an incidental water vapor (humidity) measurement and a separate oxygen (O2) channel using a vertical cavity surface emitting laser (VCSEL). Both prototypes are controlled digitally with a field-programmable gate array (FPGA)/microcontroller architecture. Based on the results of the initial instrument development, further prototype development and testing of instruments leveraging the lessons learned were desired. The present development extends and upgrades the earlier hardware to the Advanced PLSS 2.0 test article being constructed and tested at JSC. Various improvements to the electronics and gas sampling are being advanced by this project. The combination of low power electronics with the performance of a long wavelength laser spectrometer enables multi-gas sensors with significantly increased performance over that presently offered in the EMU. .

  10. The geochemical controls on vent fluids from the Lucky Strike vent field, Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Von Damm, K. L.; Bray, A. M.; Buttermore, L. G.; Oosting, S. E.

    1998-08-01

    Hydrothermal vent fluids were collected from the Lucky Strike site at 37°17'N on the Mid-Atlantic Ridge in both 1993 and 1996. Seven vents were sampled with the DSV Alvin in 1993 and six vents were sampled in 1996 using the ROV Jason during the LUSTRE '96 Cruise. As three of the vents were sampled in both 1993 and in 1996, a time series of vent fluid chemistry is also reported. Measured temperatures ranged from 202 to 333°C at the 1618-1726 m depth of the vent field, which is located on Lucky Strike Seamount. These fluids are either equal to or less than the local bottom seawater in chlorinity. While the range in fluid compositions at Lucky Strike is generally within that observed elsewhere, the unusual aspects of the fluid chemistries are the relatively high pH and low Fe, Mn, Li and Zn. We attribute this, as well as an usually low Sr/Ca ratio, to reaction with a highly altered substrate. The high Si and Cu contents suggest a deep, as well as hot, source for these fluids. The fluid compositions therefore suggest formation by super-critical phase separation at a depth not less than 1300 m below the seafloor, and reaction with a relatively oxic, and previously altered, substrate. There is temporal variability in some of the vent fluid compositions as Li, K, Ca and Fe concentrations have increased in some of the vents, as has the Fe/Mn (molar) ratio, although the chlorinities have remained essentially constant from 1993 to 1996. While there is not a simple relationship between vent fluid compositions (or temperatures) and distance from the lava lake at the summit of the seamount, the vent fluids from many of the vents can be shown to be related to others, often at distances >200 m. The most southeasterly vents (Eiffel Tower and the Marker/Mounds vents) are distinct in chlorinity and other chemical parameters from the rest of the vents, although closely related to each other within the southeastern area. Similarly all of the vents not in this one area, appear

  11. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-13 Venting... outlet connections of the valves. (b) Threads for openings must be National Gas Taper Threads (NGT... (h)(3)(ii). Threads for the clean-out/inspection ports of DOT Specification 110A multi-unit tank...

  12. 49 CFR 179.300-13 - Venting, loading and unloading valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-13 Venting... outlet connections of the valves. (b) Threads for openings must be National Gas Taper Threads (NGT... (h)(3)(ii). Threads for the clean-out/inspection ports of DOT Specification 110A multi-unit tank...

  13. 40 CFR 63.489 - Batch front-end process vents-monitoring equipment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Batch front-end process vents-monitoring equipment. 63.489 Section 63.489 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... installed in the gas stream immediately before and after the catalyst bed. (2) Where a flare is used,...

  14. 40 CFR 63.645 - Test methods and procedures for miscellaneous process vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... process vent TOC mass flow rate is less than 33 kilograms per day for an existing source or less than 6.8... shall determine the TOC mass flow rate by the following procedures: (1) The sampling site shall be selected as specified in paragraph (e) of this section. (2) The gas volumetric flow rate shall...

  15. Bonded carbon or ceramic fiber composite filter vent for radioactive waste

    SciTech Connect

    Brassell, Gilbert W.; Brugger, Ronald P.

    1985-02-19

    Carbon bonded carbon fiber composites as well as ceramic or carbon bonded ceramic fiber composites are very useful as filters which can separate particulate matter from gas streams entraining the same. These filters have particular application to the filtering of radioactive particles, e.g., they can act as vents for containers of radioactive waste material.

  16. 40 CFR 63.1324 - Batch process vents-monitoring equipment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... such as low leg drains, high point bleeds, analyzer vents, open-ended valves or lines, and pressure... recorder shall be located at the scrubber influent for liquid flow. Gas stream flow shall be determined... appropriate adjustments for pressure drop. (B) If the scrubber is subject to regulations in 40 CFR parts...

  17. 77 FR 22387 - Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-13

    ... Pipeline and Hazardous Materials Safety Administration Pipeline Safety: Information Collection Activities, Revision to Gas Transmission and Gathering Pipeline Systems Annual Report, Gas Transmission and Gathering Pipeline Systems Incident Report, and Hazardous Liquid Pipeline Systems Accident Report AGENCY:...

  18. Cost leveling continues; planned activity drops sharply in US gas pipeline cnstruction

    SciTech Connect

    Morgan, J.M.

    1986-02-01

    Natural gas pipeline construction costs, as measured by the OGJ-Morgan Pipeline cost index for US gas-pipeline construction, barely crept up in the second quarter 1985. Construction activity for lines and compressor stations was down.

  19. Fugitive greenhouse gas emissions from shale gas activities - a case study of Dish, TX

    NASA Astrophysics Data System (ADS)

    Khan, A.; Roscoe, B.; Lary, D.; Schaefer, D.; Tao, L.; Sun, K.; Brian, A.; DiGangi, J.; Miller, D. J.; Zondlo, M. A.

    2012-12-01

    We evaluate new findings on aerial (horizontal and vertical) mapping of methane emissions in the atmospheric boundary layer region to help study fugitive methane emissions from extraction, transmission, and storage of natural gas and oil in Dish, Texas. Dish is located in the Barnett Shale which has seen explosive development of hydraulic fracking activities in recent years. The aerial measurements were performed with a new laser-based methane sensor developed specifically for an unmanned aerial vehicle (UAV). The vertical cavity surface emitting laser (VCSEL) methane sensor, with a mass of 2.5 kg and a precision of < 20 ppbv methane at 1 Hz, was flown on the UT-Dallas ARC Payload Master electronic aircraft at two sites in Texas: one representative of urban emissions of the Dallas-Fort Worth area in Richardson, Texas and another in Dish, Texas, closer to gas and oil activities. Methane mixing ratios at Dish were ubiquitously in the 3.5 - 4 ppmv range which was 1.5 - 2 ppmv higher than methane levels immediately downwind of Dallas. During the flight measurements at Dish, narrow methane plumes exceeding 20 ppmv were frequently observed at altitudes from the surface to 130 m above the ground. Based on the wind speed at the sampling location, the horizontal widths of large methane plumes were of the order of 100 m. The locations of the large methane plumes were variable in space and time over a ~ 1 km2 area sampled from the UAV. Spatial mapping over larger scales (10 km) by ground-based measurements showed similar methane levels as the UAV measurements. To corroborate our measurements, alkane and other hydrocarbon mixing ratios from an on-site TCEQ environmental monitoring station were analyzed and correlated with methane measurements to fingerprint the methane source. We show that fugitive methane emissions at Dish are a significant cause of the large and ubiquitous methane levels on the 1-10 km scale.

  20. 26 CFR 1.263A-13 - Oil and gas activities.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 3 2010-04-01 2010-04-01 false Oil and gas activities. 1.263A-13 Section 1.263A... (CONTINUED) INCOME TAXES Items Not Deductible § 1.263A-13 Oil and gas activities. (a) In general. This... 263A(g)) of oil or gas property. For this purpose, oil or gas property consists of each...

  1. 26 CFR 1.263A-13 - Oil and gas activities.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 26 Internal Revenue 3 2013-04-01 2013-04-01 false Oil and gas activities. 1.263A-13 Section 1.263A... (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-13 Oil and gas activities. (a) In general... section 263A(g)) of oil or gas property. For this purpose, oil or gas property consists of each...

  2. 26 CFR 1.263A-13 - Oil and gas activities.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 26 Internal Revenue 3 2012-04-01 2012-04-01 false Oil and gas activities. 1.263A-13 Section 1.263A... (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-13 Oil and gas activities. (a) In general... section 263A(g)) of oil or gas property. For this purpose, oil or gas property consists of each...

  3. 26 CFR 1.263A-13 - Oil and gas activities.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 3 2014-04-01 2014-04-01 false Oil and gas activities. 1.263A-13 Section 1.263A... (CONTINUED) INCOME TAXES (CONTINUED) Items Not Deductible § 1.263A-13 Oil and gas activities. (a) In general... section 263A(g)) of oil or gas property. For this purpose, oil or gas property consists of each...

  4. Apparatus and method for gas turbine active combustion control system

    NASA Technical Reports Server (NTRS)

    Umeh, Chukwueloka (Inventor); Kammer, Leonardo C. (Inventor); Shah, Minesh (Inventor); Fortin, Jeffrey B. (Inventor); Knobloch, Aaron (Inventor); Myers, William J. (Inventor); Mancini, Alfred Albert (Inventor)

    2011-01-01

    An Active Combustion Control System and method provides for monitoring combustor pressure and modulating fuel to a gas turbine combustor to prevent combustion dynamics and/or flame extinguishments. The system includes an actuator, wherein the actuator periodically injects pulsed fuel into the combustor. The apparatus also includes a sensor connected to the combustion chamber down stream from an inlet, where the sensor generates a signal detecting the pressure oscillations in the combustor. The apparatus controls the actuator in response to the sensor. The apparatus prompts the actuator to periodically inject pulsed fuel into the combustor at a predetermined sympathetic frequency and magnitude, thereby controlling the amplitude of the pressure oscillations in the combustor by modulating the natural oscillations.

  5. Investigating pyroclast ejection dynamics using shock-tube experiments: temperature, grain size and vent geometry effects.

    NASA Astrophysics Data System (ADS)

    Cigala, V.; Kueppers, U.; Dingwell, D. B.

    2015-12-01

    Explosive volcanic eruptions eject large quantities of gas and particles into the atmosphere. The portion directly above the vent commonly shows characteristics of underexpanded jets. Understanding the factors that influence the initial pyroclast ejection dynamics is necessary in order to better assess the resulting near- and far-field hazards. Field observations are often insufficient for the characterization of volcanic explosions due to lack of safe access to such environments. Fortunately, their dynamics can be simulated in the laboratory where experiments are performed under controlled conditions. We ejected loose natural particles from a shock-tube while controlling temperature (25˚ and 500˚C), overpressure (15MPa), starting grain size distribution (1-2 mm, 0.5-1 mm and 0.125-0.250 mm), sample-to-vent distance and vent geometry. For each explosion we quantified the velocity of individual particles, the jet spreading angle and the production of fines. Further, we varied the setup to allow for different sample-to-gas ratios and deployed four different vent geometries: 1) cylindrical, 2) funnel with a flaring of 30˚, 3) funnel with a flaring of 15˚ and 4) nozzle. The results showed maximum particle velocities up to 296 m/s, gas spreading angles varying from 21˚ to 37˚ and particle spreading angles from 3˚ to 40˚. Moreover we observed dynamically evolving ejection characteristics and variations in the production of fines during the course of individual experiments. Our experiments mechanistically mimic the process of pyroclast ejection. Thus the capability for constraining the effects of input parameters (fragmentation conditions) and conduit/vent geometry on ballistic pyroclastic plumes has been clearly established. These data obtained in the presence of well-documented conduit and vent conditions, should greatly enhance our ability to numerically model explosive ejecta in nature.

  6. Des Vents et des Jets Astrophysiques

    NASA Astrophysics Data System (ADS)

    Sauty, C.

    Plasma outflows from a central gravitating object are a widespread phenomenon in astrophysics. They include the solar and stellar winds, jets from Young Stellar Objects, jets from compact stellar objects and extra-galactic jets associated with Active Galactic Nuclei and quasars. Beyond this huge zoology, a common theoretical ground exists. The aim of this review is to present qualitatively the various theories of winds (Part 1) and how different astrophysical domains interplay. A more or less complete catalog of the ideas proposed for explaining the acceleration and the morphologies of winds and jets is intended. All this part avoids getting into any mathematical formalism. Some macroscopic properties of such outflows may be described by solving the time-independent and axisymmetric magnetohydrodynamic equations. This formalism, underlying most of the theories, is presented in Part 2. It helps to introduce quantitatively the free integrals that such systems possess. Those integrals play an important role in the basic physics of acceleration and collimation, in particular the mass loss rate, the angular momentum loss rate and the energy of the magnetic rotator. Most of the difficulty in modelling flows lies in the necessity to cross critical points, characteristic of non linear equations. The physical nature and the location of such critical points is debated because they are the clue towards the resolution. We thus introduce the notions of topology and critical points (Parts 3 and 4) from the simplest hydrodynamic and spherically symmetric case to the most sophisticated, MHD and axisymmetric cases. Particular attention is given to self-similar models which allows to give some general and simple ideas on the problem due to their semi-analytical treatment. With the use of these notions, a more quantitative comparison of the various models is given (Parts 3 and 4), especially on the shape of the flows. It is thus shown that magnetic collimation of winds into jets is a

  7. Geomicrobiology of sublacustrine thermal vents in Yellowstone Lake: geochemical controls on microbial community structure and function

    PubMed Central

    Inskeep, William P.; Jay, Zackary J.; Macur, Richard E.; Clingenpeel, Scott; Tenney, Aaron; Lovalvo, David; Beam, Jacob P.; Kozubal, Mark A.; Shanks, W. C.; Morgan, Lisa A.; Kan, Jinjun; Gorby, Yuri; Yooseph, Shibu; Nealson, Kenneth

    2015-01-01

    Yellowstone Lake (Yellowstone National Park, WY, USA) is a large high-altitude (2200 m), fresh-water lake, which straddles an extensive caldera and is the center of significant geothermal activity. The primary goal of this interdisciplinary study was to evaluate the microbial populations inhabiting thermal vent communities in Yellowstone Lake using 16S rRNA gene and random metagenome sequencing, and to determine how geochemical attributes of vent waters influence the distribution of specific microorganisms and their metabolic potential. Thermal vent waters and associated microbial biomass were sampled during two field seasons (2007–2008) using a remotely operated vehicle (ROV). Sublacustrine thermal vent waters (circa 50–90°C) contained elevated concentrations of numerous constituents associated with geothermal activity including dissolved hydrogen, sulfide, methane and carbon dioxide. Microorganisms associated with sulfur-rich filamentous “streamer” communities of Inflated Plain and West Thumb (pH range 5–6) were dominated by bacteria from the Aquificales, but also contained thermophilic archaea from the Crenarchaeota and Euryarchaeota. Novel groups of methanogens and members of the Korarchaeota were observed in vents from West Thumb and Elliot's Crater (pH 5–6). Conversely, metagenome sequence from Mary Bay vent sediments did not yield large assemblies, and contained diverse thermophilic and nonthermophilic bacterial relatives. Analysis of functional genes associated with the major vent populations indicated a direct linkage to high concentrations of carbon dioxide, reduced sulfur (sulfide and/or elemental S), hydrogen and methane in the deep thermal ecosystems. Our observations show that sublacustrine thermal vents in Yellowstone Lake support novel thermophilic communities, which contain microorganisms with functional attributes not found to date in terrestrial geothermal systems of YNP. PMID:26579074

  8. Geomicrobiology of sublacustrine thermal vents in Yellowstone Lake: geochemical controls on microbial community structure and function.

    PubMed

    Inskeep, William P; Jay, Zackary J; Macur, Richard E; Clingenpeel, Scott; Tenney, Aaron; Lovalvo, David; Beam, Jacob P; Kozubal, Mark A; Shanks, W C; Morgan, Lisa A; Kan, Jinjun; Gorby, Yuri; Yooseph, Shibu; Nealson, Kenneth

    2015-01-01

    Yellowstone Lake (Yellowstone National Park, WY, USA) is a large high-altitude (2200 m), fresh-water lake, which straddles an extensive caldera and is the center of significant geothermal activity. The primary goal of this interdisciplinary study was to evaluate the microbial populations inhabiting thermal vent communities in Yellowstone Lake using 16S rRNA gene and random metagenome sequencing, and to determine how geochemical attributes of vent waters influence the distribution of specific microorganisms and their metabolic potential. Thermal vent waters and associated microbial biomass were sampled during two field seasons (2007-2008) using a remotely operated vehicle (ROV). Sublacustrine thermal vent waters (circa 50-90°C) contained elevated concentrations of numerous constituents associated with geothermal activity including dissolved hydrogen, sulfide, methane and carbon dioxide. Microorganisms associated with sulfur-rich filamentous "streamer" communities of Inflated Plain and West Thumb (pH range 5-6) were dominated by bacteria from the Aquificales, but also contained thermophilic archaea from the Crenarchaeota and Euryarchaeota. Novel groups of methanogens and members of the Korarchaeota were observed in vents from West Thumb and Elliot's Crater (pH 5-6). Conversely, metagenome sequence from Mary Bay vent sediments did not yield large assemblies, and contained diverse thermophilic and nonthermophilic bacterial relatives. Analysis of functional genes associated with the major vent populations indicated a direct linkage to high concentrations of carbon dioxide, reduced sulfur (sulfide and/or elemental S), hydrogen and methane in the deep thermal ecosystems. Our observations show that sublacustrine thermal vents in Yellowstone Lake support novel thermophilic communities, which contain microorganisms with functional attributes not found to date in terrestrial geothermal systems of YNP.

  9. Dust collector venting: Don't take chances

    SciTech Connect

    Black, G.J.

    1994-02-01

    Fabric dust collectors, widely used throughout the process industries, pose risk of explosion because they handle large volumes of dust-laden gas. This risk is addressed by outfitting the collection vessels with vent devices that open when the internal pressure exceeds a preselected level. The most widely accepted basis for selecting, sizing and placing these vents is the National Fire Protection Assn. (Quincy, Mass) Standard 68, 1988 edition (NFPA-68). Any engineer who is or expects to become involved with dust collectors should have a clear understanding of its provisions. And because NFPA-68 is not a rigid code but instead a guideline with numerous portions open to interpretation, the engineer may also benefit from the insights of people (such as the author) experienced in applying it. Of special relevance in the chemical process industries is the portion of NFPA-68 that covers high-strength enclosures in which operating pressure is less than 80 in. w.c. (0.2 bar gage), air is the gas in which the potentially explosive dust is suspended, and the length-to-diameter ratio is less than 5. This article focuses on that portion of the standard.

  10. Approximating Fluid Flow from Ambient to Very Low Pressures: Modeling ISS Experiments that Vent to Vacuum

    NASA Technical Reports Server (NTRS)

    Minor, Robert

    2002-01-01

    Two ISS (International Space Station) experiment payloads will vent a volume of gas overboard via either the ISS Vacuum Exhaust System or the Vacuum Resource System. A system of ducts, valves and sensors, under design, will connect the experiments to the ISS systems. The following tasks are required: Create an analysis tool that will verify the rack vacuum system design with respect to design requirements, more specifically approximate pressure at given locations within the vacuum systems; Determine the vent duration required to achieve desired pressure within the experiment modules; Update the analysis as systems and operations definitions mature.

  11. 40 CFR Table 8 to Subpart Hhhhhhh... - Methods and Procedures for Conducting Performance Tests for Process Vents

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... gas per test run; orii. Method 26A at 40 CFR part 60, appendix A-8, collect 1 dry standard cubic meter... Method 23 at 40 CFR part 60, appendix A-7 and collect 5 dry standard cubic meters of gas per test run. 6... Performance Tests for Process Vents 8 Table 8 to Subpart HHHHHHH of Part 63 Protection of...

  12. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  13. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  14. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  15. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  16. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  17. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fuel tank vents and carburetor vapor vents. 29.975 Section 29.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Fuel System §...

  18. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  19. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fuel tank vents and carburetor vapor vents. 25.975 Section 25.975 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: TRANSPORT CATEGORY AIRPLANES Powerplant Fuel System §...

  20. 14 CFR 23.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... will constitute a fire hazard or from which fumes may enter personnel compartments; and (7) Vents must... a separate vent line to lead vapors back to the top of one of the fuel tanks. If there is more than... line must lead back to the fuel tank to be used first, unless the relative capacities of the tanks...

  1. 14 CFR 25.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... may end at any point— (i) Where the discharge of fuel from the vent outlet would constitute a fire... carburetor with vapor elimination connections must have a vent line to lead vapors back to one of the fuel... return line must lead back to the fuel tank used for takeoff and landing....

  2. 14 CFR 29.975 - Fuel tank vents and carburetor vapor vents.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... end at any point— (i) Where the discharge of fuel from the vent outlet would constitute a fire hazard... with vapor elimination connections must have a vent line to lead vapors back to one of the fuel tanks... line must lead back to the fuel tank used for takeoff and landing....

  3. Constrained circulation at Endeavour ridge facilitates colonization by vent larvae.

    PubMed

    Thomson, Richard E; Mihály, Steven F; Rabinovich, Alexander B; McDuff, Russell E; Veirs, Scott R; Stahr, Frederick R

    2003-07-31

    Understanding how larvae from extant hydrothermal vent fields colonize neighbouring regions of the mid-ocean ridge system remains a major challenge in oceanic research. Among the factors considered important in the recruitment of deep-sea larvae are metabolic lifespan, the connectivity of the seafloor topography, and the characteristics of the currents. Here we use current velocity measurements from Endeavour ridge to examine the role of topographically constrained circulation on larval transport along-ridge. We show that the dominant tidal and wind-generated currents in the region are strongly attenuated within the rift valley that splits the ridge crest, and that hydrothermal plumes rising from vent fields in the valley drive a steady near-bottom inflow within the valley. Extrapolation of these findings suggests that the suppression of oscillatory currents within rift valleys of mid-ocean ridges shields larvae from cross-axis dispersal into the inhospitable deep ocean. This effect, augmented by plume-driven circulation within rift valleys having active hydrothermal venting, helps retain larvae near their source. Larvae are then exported preferentially down-ridge during regional flow events that intermittently over-ride the currents within the valley.

  4. Hydrothermal vents is Lake Tanganyika, East African Rift system

    SciTech Connect

    Tiercelin, J.J.; Pflumio, C.; Castrec, M.

    1993-06-01

    Sublacustrine hydrothermal vents with associated massive sulfides were discovered during April 1987 at Pemba and Cape Banza on the Zaire side of the northern basin of Lake Tanganyika, East African Rift system. New investigations by a team of ten scuba divers during the multinational (France, Zaire, Germany, and Burundi) TANGANYDRO expedition (August-October 1991) found hydrothermal vents down to a depth of 46 m along north-trending active faults bounding the Tanganyika rift on the western side. Temperatures from 53 to 103 {degrees}C were measured in hydrothermal fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with vents at the Pemba site. At Cape Banza, active vents are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of hydrothermal pipes. Hydrothermal fluid end members show distinctive compositions at the two sites. The Pemba end member is a NaHCO{sub 3}-enriched fluid similar to the NaHCO{sub 3} thermal fluids form lakes Magadi and Bogoria in the eastern branch of the rift. The Cape Banza end member is a solution enriched in NaCl. Such brines may have a deep-seated basement origin, as do the Uvinza NaCl brines on the eastern flank of the Tanganyika basin. Geothermometric calculations have yielded temperatures of fluid-rock interaction of 219 and 179 {degrees}C in the Pemba and Cape Banza systems, respectively. Abundant white or reddish-brown microbial colonies resembling Beggiatoa mats were found surrounding the active vents. Thermal fluid circulation is permitted by opening of cracks related to 130{degrees}N normal-dextral faults that intersect the north-south major rift trend. The sources of heat for such hydrothermal systems may relate to the existence of magmatic bodies under the rift, which is suggested by the isotopic composition of carbon dioxide released at Pemba and Cape Banza. 21 refs., 2 figs.

  5. Exploration of the 1891 Foerstner submarine vent site (Pantelleria, Italy): insights into the formation of basaltic balloons

    NASA Astrophysics Data System (ADS)

    Kelly, Joshua T.; Carey, Steven; Pistolesi, Marco; Rosi, Mauro; Croff-Bell, Katherine Lynn; Roman, Chris; Marani, Michael

    2014-07-01

    On October 17, 1891, a submarine eruption started at Foerstner volcano located within the Pantelleria Rift of the Strait of Sicily (Italy). Activity occurred for a period of 1 week from an eruptive vent located 4 km northwest of the island of Pantelleria at a water depth of 250 m. The eruption produced lava balloons that discharged gas at the surface and eventually sank to the seafloor. Remotely operated vehicle (ROV) video footage and high-resolution multi-beam mapping of the Foerstner vent site were used to create a geologic map of the AD 1891 deposits and conduct the first detailed study of the source area associated with this unusual type of submarine volcanism. The main Foerstner vent consists of two overlapping circular mounds with a total volume of 6.3 × 105 m3 and relief of 60 m. It is dominantly constructed of clastic scoriaceous deposits with some interbedded pillow lavas. Petrographic and geochemical analyses of Foerstner samples by X-ray fluorescence and inductively coupled plasma mass spectrometry reveal that the majority of the deposits are vesicular, hypocrystalline basanite scoria that display porphyritic, hyaloophitic, and vitrophyric textures. An intact lava balloon recovered from the seafloor consists of a large interior gas cavity surrounded by a thin lava shell comprising two distinct layers: a thin, oxidized, quenched crust surrounding the exterior of the balloon and a dark gray, tachylite layer lying beneath it. Ostwald ripening is proposed to be the dominant bubble growth mechanism of four representative Foerstner scoria samples as inferred by vesicle size distributions. Characterization of the diversity of deposit facies observed at Foerstner in conjunction with quantitative rock texture analysis indicates that submarine Strombolian-like activity is the most likely mechanism for the formation of lava balloons. The deposit facies observed at the main Foerstner vent are very similar to those produced by other known submarine Strombolian

  6. Lava-flow hazard with optimized non-uniform grid of vents

    NASA Astrophysics Data System (ADS)

    Lucà, Federica; Rongo, Rocco; Lupiano, Valeria; Iovine, Giulio

    2016-10-01

    The aim of the study is to assess the sensitivity to vents (in terms of number and distribution) of sectors affected by lava flows and of hazard values at Mount Etna. The proposed methodology relies on the application of the Cellular Automata model SCIARA, and on the adoption of an optimization algorithm for progressively integrating an initial uniform distribution of 1006 vents (1-km spaced) with 500 additional sources. Vents have iteratively been added, at steps of 50, through spatial simulated annealing, using slope roughness as weigh function. For each vent, 41 types of simulations have been executed to take into proper account the potential behaviour of the volcano, based on historical records. The performed simulations have been further processed to derive lava-flow hazard, by assigning each simulation: i) a spatial likelihood of vent opening; ii) a magnitude probability, depending on the type of eruption; and iii) a temporal probability of source activation, based on historical occurrences in the past 400 years. First results are discussed, and the influence of the number and distribution of additional vents is preliminarily investigated.

  7. Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise

    PubMed Central

    German, C. R.; Bowen, A.; Coleman, M. L.; Honig, D. L.; Huber, J. A.; Jakuba, M. V.; Kinsey, J. C.; Kurz, M. D.; Leroy, S.; McDermott, J. M.; de Lépinay, B. Mercier; Nakamura, K.; Seewald, J. S.; Smith, J. L.; Sylva, S. P.; Van Dover, C. L.; Whitcomb, L. L.; Yoerger, D. R.

    2010-01-01

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world’s ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the ∼110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at ∼5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity—all in close proximity. PMID:20660317

  8. Diverse styles of submarine venting on the ultraslow spreading Mid-Cayman Rise.

    PubMed

    German, C R; Bowen, A; Coleman, M L; Honig, D L; Huber, J A; Jakuba, M V; Kinsey, J C; Kurz, M D; Leroy, S; McDermott, J M; de Lépinay, B Mercier; Nakamura, K; Seewald, J S; Smith, J L; Sylva, S P; Van Dover, C L; Whitcomb, L L; Yoerger, D R

    2010-08-10

    Thirty years after the first discovery of high-temperature submarine venting, the vast majority of the global mid-ocean ridge remains unexplored for hydrothermal activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature venting but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep hydrothermal vents along the approximately 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete hydrothermal sites, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at approximately 5,000 m, the deepest known hydrothermal vent. Although submarine hydrothermal circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of vent types identified here and their relative geographic isolation make the MCR unique in the oceans. These new sites offer prospects for an expanded range of vent-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity--all in close proximity.

  9. 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...

  10. 78 FR 68079 - Information Collection Activities: Oil and Gas Well-Completion Operations; Submitted for Office...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-13

    ...; 134E1700D2 EEEE500000 ET1SF0000.DAQ000] Information Collection Activities: Oil and Gas Well-Completion... requirements in the regulations under Subpart E, Oil and Gas Well Completion Operations. This notice also... INFORMATION: Title: 30 CFR 250, Subpart E, Oil and Gas Well-Completion Operations. OMB Control Number:...

  11. 78 FR 13657 - Southwest Gas Storage Company; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-28

    .... Southwest seeks authorization to construct, modify and abandon certain natural gas storage facilities at the... Energy Regulatory Commission Southwest Gas Storage Company; Prior Notice of Activity Under Blanket Certificate On February 8, 2013, Southwest Gas Storage Company (Southwest) filed a prior notice...

  12. Design of hydrogen vent line for the cryogenic hydrogen system in J-PARC

    NASA Astrophysics Data System (ADS)

    Tatsumoto, Hideki; Aso, Tomokazu; Kato, Takashi; Ohtsu, Kiichi; Hasegawa, Shoichi; Maekawa, Fujio; Futakawa, Masatoshi

    2009-02-01

    As one of the main experimental facilities in J-PARC, an intense spallation neutron source (JSNS) driven by a 1-MW proton beam selected supercritical hydrogen at a temperature of 20 K and a pressure of 1.5 MPa as a moderator material. Moderators are controlled by a cryogenic hydrogen system that has a hydrogen relief system, which consists of high and low pressure stage of manifolds, a hydrogen vent line and a stack, in order to release hydrogen to the outside safely. The design of the hydrogen vent line should be considered to prevent purge nitrogen gas in the vent line from freezing when releasing the cryogenic hydrogen, to prevent moisture in the stack placed in an outdoor location from freezing, and to inhibit large piping temperature reduction at a building wall penetration. In this work, temperature change behaviors in the hydrogen vent line were analyzed by using a CFD code, STAR-CD. We determined required sizes of the vent line based on the analytical results and its layout in the building.

  13. How many vent fields? New estimates of vent field populations on ocean ridges from precise mapping of hydrothermal discharge locations

    NASA Astrophysics Data System (ADS)

    Baker, Edward T.; Resing, Joseph A.; Haymon, Rachel M.; Tunnicliffe, Verena; Lavelle, J. William; Martinez, Fernando; Ferrini, Vicki; Walker, Sharon L.; Nakamura, Koichi

    2016-09-01

    Decades of exploration for venting sites along spreading ridge crests have produced global datasets that yield estimated mean site spacings of ∼ 12- 220 km. This conclusion demands that sites where hydrothermal fluid leaks from the seafloor are improbably rare along the 66 000 km global ridge system, despite the high bulk permeability of ridge crest axes. However, to date, exploration methods have neither reliably detected plumes from isolated low-temperature, particle-poor, diffuse sources, nor differentiated individual, closely spaced (clustered within a few kilometers) sites of any kind. Here we describe a much lower mean discharge spacing of 3-20 km, revealed by towing real-time oxidation-reduction-potential and optical sensors continuously along four fast- and intermediate-rate (>55 mm/yr) spreading ridge sections totaling 1470 km length. This closer spacing reflects both discovery of isolated sites discharging particle-poor plumes (25% of all sites) and improved discrimination (at a spatial resolution of ∼1 km) among clustered discrete and diffuse sources. Consequently, the number of active vent sites on fast- and intermediate-rate spreading ridges may be at least a factor of 3-6 higher than now presumed. This increase provides new quantitative constraints for models of seafloor processes such as dispersal of fauna among seafloor and crustal chemosynthetic habitats, biogeochemical impacts of diffuse venting, and spatial patterns of hydrothermal discharge.

  14. Feasibility and Safety Assessment for Advanced Reactor Concepts Using Vented Fuel

    SciTech Connect

    Klein, Andrew; Matthews, Topher; Lenhof, Renae; Deason, Wesley; Harter, Jackson

    2015-01-16

    Recent interest in fast reactor technology has led to renewed analysis of past reactor concepts such as Gas Fast Reactors and Sodium Fast Reactors. In an effort to make these reactors more economic, the fuel is required to stay in the reactor for extended periods of time; the longer the fuel stays within the core, the more fertile material is converted into usable fissile material. However, as burnup of the fuel-rod increases, so does the internal pressure buildup due to gaseous fission products. In order to reach the 30 year lifetime requirements of some reactor designs, the fuel pins must have a vented-type design to allow the buildup of fission products to escape. The present work aims to progress the understanding of the feasibility and safety issues related to gas reactors that incorporate vented fuel. The work was separated into three different work-scopes: 1. Quantitatively determine fission gas release from uranium carbide in a representative helium cooled fast reactor; 2. Model the fission gas behavior, transport, and collection in a Fission Product Vent System; and, 3. Perform a safety analysis of the Fission Product Vent System. Each task relied on results from the previous task, culminating in a limited scope Probabilistic Risk Assessment (PRA) of the Fission Product Vent System. Within each task, many key parameters lack the fidelity needed for comprehensive or accurate analysis. In the process of completing each task, the data or methods that were lacking were identified and compiled in a Gap Analysis included at the end of the report.

  15. Prokaryote diversity and virus abundance in shallow hydrothermal vents of the Mediterranean Sea (Panarea Island) and the Pacific Ocean (north Sulawesi-Indonesia).

    PubMed

    Manini, E; Luna, G M; Corinaldesi, C; Zeppilli, D; Bortoluzzi, G; Caramanna, G; Raffa, F; Danovaro, R

    2008-05-01

    Despite their ubiquitous distribution in tectonically active coastal zones, shallow water hydrothermal vents have been less investigated than deep-sea vents. In the present study, we investigated the role of viral control and fluid emissions on prokaryote abundance, diversity, and community structure (total Archaea, total Bacteria, and sulphate-reducing bacteria) in waters and sediments surrounding the caldera of four different shallow-water hydrothermal vents (three located in the Mediterranean Sea and one in the Pacific Ocean). All vents, independent of their location, generally displayed a significant decrease of benthic prokaryote abundance, as well as its viable fraction, with increasing distance from the vent. Prokaryote assemblages were always dominated by Bacteria. Benthic Archaea accounted for 23-33% of total prokaryote abundance in the Mediterranean Sea and from 13 to 29% in the Pacific Ocean, whereas in the water column they accounted for 25-38%. The highest benthic bacterial ribotype richness was observed in close proximity of the vents (i.e., at 10-cm distance from the emissions), indicating that vent fluids might influence bacterial diversity in surrounding sediments. Virioplankton and viriobenthos abundances were low compared to other marine systems, suggesting that temperature and physical-chemical conditions might influence viral survival in these vent systems. We thus hypothesize that the high bacterial diversity observed in close proximity of the vents is related with the highly variable vent emissions, which could favor the coexistence of several prokaryotic species.

  16. Absolute activity measurement of radon gas at IRA-METAS

    NASA Astrophysics Data System (ADS)

    Spring, Philippe; Nedjadi, Youcef; Bailat, Claude; Triscone, Gilles; Bochud, François

    2006-12-01

    This paper describes the system of the Swiss national metrological institute (IRA-METAS) for the absolute standardisation of radon gas. This method relies on condensing radon under vacuum conditions within a specified cold area using a cryogenerator, and detecting its alpha particles with an ion-implanted silicon detector, through a very accurately defined solid angle. The accuracy of this defined solid angle standardisation technique was corroborated by another primary measurement method involving 4 πγ NaI(Tl) integral counting and Monte Carlo efficiency calculations. The 222Rn standard submitted by IRA-METAS to the Système International de Référence (SIR) at the Bureau International des Poids et Mesures (BIPM) has also been found to be consistent with an analogous standard submitted by the German national metrological institute (PTB). IRA-METAS is able to deliver radon standards, with activities ranging from a few kBq to 350 kBq, in NIST-Type ampoules, and glass or steel containers usable for calibrating radon-measuring instruments.

  17. Assessing submarine gas hydrate at active seeps on the Hikurangi Margin, New Zealand, using controlled source electromagnetic data with constraints from seismic, geochemistry, and heatflow data

    NASA Astrophysics Data System (ADS)

    Schwalenberg, K.; Haeckel, M.; Pecher, I. A.; Toulmin, S. J.; Hamdan, L. J.; Netzeband, G.; Wood, W.; Poort, J.; Jegen, M. D.; Coffin, R. B.

    2009-12-01

    Electrical resistivity is one of the key properties useful for evaluating submarine gas hydrate deposits. Gas hydrates are electrically insulating in contrast to the conductive pore fluid. Where they form in sufficient quantities the bulk resistivity of the sub-seafloor is elevated. CSEM data were collected in 2007 as part of the German - International “New Vents” project on R/V Sonne, cruise SO191, at three target areas on the Hikurangi subduction margin, New Zealand. The margin is characterized by widespread bottom simulating reflectors (BSR), seep structures, and active methane and fluid venting indicating the potential for gas hydrate formation. Opouawe Bank is one of the ridge and basin systems on the accretionary wedge and is located off the Wairarapa coast at water depths of 1000-1100 m. The first observed seep sites (North Tower, South Tower, Pukeko, Takahe, and Tui) were identified from individual gas flares in hydro-acoustic data and video observations during voyages on R/V Tangaroa. Seismic reflection data collected during SO191 subsequently identified more than 25 new seep structures. Two intersecting CSEM profiles have been surveyed across North Tower, South Tower, and Takahe. 1-D inversion of the data reveals anomalously high resistivities at North Tower and South Tower, moderately elevated resistivities at Takahe, and normal background resistivities away from the seeps. The high resistivities are attributed to gas hydrate layers at intermediate depths beneath the seeps. At South Tower the hydrate concentration could be possibly as much as 25% of the total sediment volume within a 50m thick layer. This conforms with geochemical pore water analyses which show a trend of increased methane flux towards South Tower. At Takahe, gas pockets and patchy gas hydrate, as well as sediment heterogeneities and carbonates, or temperature driven upward fluid flow indicated by the observed higher heat flow at this site may explain the resistivity pattern

  18. Medium Fidelity Simulation of Oxygen Tank Venting

    NASA Technical Reports Server (NTRS)

    Sweet, Adam; Kurien, James; Lau, Sonie (Technical Monitor)

    2001-01-01

    The item to he cleared is a medium-fidelity software simulation model of a vented cryogenic tank. Such tanks are commonly used to transport cryogenic liquids such as liquid oxygen via truck, and have appeared on liquid-fueled rockets for decades. This simulation model works with the HCC simulation system that was developed by Xerox PARC and NASA Ames Research Center. HCC has been previously cleared for distribution. When used with the HCC software, the model generates simulated readings for the tank pressure and temperature as the simulated cryogenic liquid boils off and is vented. Failures (such as a broken vent valve) can be injected into the simulation to produce readings corresponding to the failure. Release of this simulation will allow researchers to test their software diagnosis systems by attempting to diagnose the simulated failure from the simulated readings. This model does not contain any encryption software nor can it perform any control tasks that might be export controlled.

  19. Investigations Into Tank Venting for Propellant Resupply

    NASA Technical Reports Server (NTRS)

    Hearn, H. C.; Harrison, Robert A. (Technical Monitor)

    2002-01-01

    Models and simulations have been developed and applied to the evaluation of propellant tank ullage venting, which is integral to one approach for propellant resupply. The analytical effort was instrumental in identifying issues associated with resupply objectives, and it was used to help develop an operational procedure to accomplish the desired propellant transfer for a particular storable bipropellant system. Work on the project was not completed, and several topics have been identified as requiring further study; these include the potential for liquid entrainment during the low-g and thermal/freezing effects in the vent line and orifice. Verification of the feasibility of this propellant venting and resupply approach still requires additional analyses as well as testing to investigate the fluid and thermodynamic phenomena involved.

  20. Data inconsistencies from states with unconventional oil and gas activity.

    PubMed

    Malone, Samantha; Kelso, Matthew; Auch, Ted; Edelstein, Karen; Ferrar, Kyle; Jalbert, Kirk

    2015-01-01

    The quality and availability of unconventional oil and gas (O&G) data in the United States have never been compared methodically state-to-state. By conducting such an assessment, this study seeks to better understand private and publicly sourced data variability and to identify data availability gaps. We developed an exploratory data-grading tool - Data Accessibility and Usability Index (DAUI) - to guide the review of O&G data quality. Between July and October 2013, we requested, collected, and assessed 5 categories of unconventional O&G data (wells drilled, violations, production, waste, and Class II disposal wells) from 10 states with active drilling activity. We based our assessment on eight data quality parameters (accessibility, usability, point location, completeness, metadata, agency responsiveness, accuracy, and cost). Using the DAUI, two authors graded the 10 states and then averaged their scores. The average score received across all states, data categories, and parameters was 67.1 out of 100, largely insufficient for proper data transparency. By state, Pennsylvania received the highest average ( = 93.5) and ranked first in all but one data category. The lowest scoring state was Texas ( = 44) largely due to its policy of charging for certain data. This article discusses the various reasons for scores received, as well as methodological limitations of the assessment metrics. We argue that the significant variability of unconventional O&G data-and its availability to the public-is a barrier to regulatory and industry transparency. The lack of transparency also impacts public education and broader participation in industry governance. This study supports the need to develop a set of data best management practices (BMPs) for state regulatory agencies and the O&G industry, and suggests potential BMPs for this purpose.

  1. Effects of Activation Energy to Transient Response of Semiconductor Gas Sensor

    NASA Astrophysics Data System (ADS)

    Fujimoto, Akira; Ohtani, Tatsuki

    The smell classifiable gas sensor will be desired for many applications such as gas detection alarms, process controls for food production and so on. We have tried to realize the sensor using transient responses of semiconductor gas sensor consisting of tin dioxide and pointed out that the sensor gave us different transient responses for kinds of gas. Results of model calculation showed the activation energy of chemical reaction on the sensor surface strongly depended on the transient response. We tried to estimate the activation energies by molecular orbital calculation with SnO2 Cluster. The results show that there is a liner relationship between the gradient of the transient responses and activation energies for carboxylic and alcoholic gases. Transient response will be predicted from activation energy in the same kind of gas and the smell discrimination by single semiconductor gas sensor will be realized by this relationship.

  2. Vented Cavity Radiant Barrier Assembly And Method

    DOEpatents

    Dinwoodie, Thomas L.; Jackaway, Adam D.

    2000-05-16

    A vented cavity radiant barrier assembly (2) includes a barrier (12), typically a PV module, having inner and outer surfaces (18, 22). A support assembly (14) is secured to the barrier and extends inwardly from the inner surface of the barrier to a building surface (14) creating a vented cavity (24) between the building surface and the barrier inner surface. A low emissivity element (20) is mounted at or between the building surface and the barrier inner surface. At least part of the cavity exit (30) is higher than the cavity entrance (28) to promote cooling air flow through the cavity.

  3. Hydrothermal vents and the origin of life.

    PubMed

    Martin, William; Baross, John; Kelley, Deborah; Russell, Michael J

    2008-11-01

    Submarine hydrothermal vents are geochemically reactive habitats that harbour rich microbial communities. There are striking parallels between the chemistry of the H(2)-CO(2) redox couple that is present in hydrothermal systems and the core energy metabolic reactions of some modern prokaryotic autotrophs. The biochemistry of these autotrophs might, in turn, harbour clues about the kinds of reactions that initiated the chemistry of life. Hydrothermal vents thus unite microbiology and geology to breathe new life into research into one of biology's most important questions - what is the origin of life?

  4. Patterns in open vent, strombolian behavior at Fuego volcano, Guatemala, 2005-2007

    NASA Astrophysics Data System (ADS)

    Lyons, John J.; Waite, Gregory P.; Rose, William I.; Chigna, Gustavo

    2010-01-01

    Fuego volcano, Guatemala is a high (3,800 m) composite volcano that erupts gas-rich, high-Al basalt, often explosively. It spends many years in an essentially open vent condition, but this activity has not been extensively observed or recorded until now. The volcano towers above a region with several tens of thousands of people, so that patterns in its activity might have hazard mitigation applications. We conducted 2 years of continuous observations at Fuego (2005-2007) during which time the activity consisted of minor explosions, persistent degassing, paroxysmal eruptions, and lava flows. Radiant heat output from MODIS correlates well with observed changes in eruptive behavior, particularly during abrupt changes from passive lava effusion to paroxysmal eruptions. A short-period seismometer and two low-frequency microphones installed during the final 6 months of the study period recorded persistent volcanic tremor (1-3 Hz) and a variety of explosive eruptions. The remarkable correlation between seismic tremor, thermal output, and daily observational data defines a pattern of repeating eruptive behavior: 1) passive lava effusion and subordinate strombolian explosions, followed by 2) paroxysmal eruptions that produced sustained eruptive columns, long, rapidly emplaced lava flows, and block and ash flows, and finally 3) periods of discrete degassing explosions with no lava effusion. This study demonstrates the utility of low-cost observations and ground-based and satellite-based remote sensing for identifying changes in volcanic activity in remote regions of underdeveloped countries.

  5. Effects of gas periodic stimulation on key enzyme activity in gas double-dynamic solid state fermentation (GDD-SSF).

    PubMed

    Chen, Hongzhang; Shao, Meixue; Li, Hongqiang

    2014-03-05

    The heat and mass transfer have been proved to be the important factors in air pressure pulsation for cellulase production. However, as process of enzyme secretion, the cellulase formation has not been studied in the view of microorganism metabolism and metabolic key enzyme activity under air pressure pulsation condition. Two fermentation methods in ATPase activity, cellulase productivity, weight lose rate and membrane permeability were systematically compared. Results indicated that gas double-dynamic solid state fermentation had no obviously effect on cell membrane permeability. However, the relation between ATPase activity and weight loss rate was linearly dependent with r=0.9784. Meanwhile, the results also implied that gas periodic stimulation had apparently strengthened microbial metabolism through increasing ATPase activity during gas double-dynamic solid state fermentation, resulting in motivating the production of cellulase by Trichoderma reesei YG3. Therefore, the increase of ATPase activity would be another crucial factor to strengthen fermentation process for cellulase production under gas double-dynamic solid state fermentation.

  6. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  7. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  8. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... relief valve and the vent outlets. (h) Provisions shall be made to drain condensate from the vent header piping. Special precautions shall insure that condensate does not accumulate at or near the relief...

  9. 40 CFR 63.690 - Standards: Process vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... process vent through a closed-vent system to a control device that meets the standards specified in § 63... a control device; however, a second condenser or other organic recovery device that is...

  10. Active Geophysical Monitoring in Oil and Gas Industry

    NASA Astrophysics Data System (ADS)

    Bakulin, A.; Calvert, R.

    2005-12-01

    Effective reservoir management is a Holy Grail of the oil and gas industry. Quest for new technologies is never ending but most often they increase effectiveness and decrease the costs. None of the newcomers proved to be a silver bullet in such a key metric of the industry as average oil recovery factor. This factor is still around 30 %, meaning that 70 % of hydrocarbon reserves are left in the ground in places where we already have expensive infrastructure (platforms, wells) to extract them. Main reason for this inefficiency is our inability to address realistic reservoir complexity. Most of the time we fail to properly characterize our reservoirs before production. As a matter of fact, one of the most important parameters -- permeability -- can not be mapped from remote geophysical methods. Therefore we always start production blind even though reservoir state before production is the simplest one. Once first oil is produced, we greatly complicate the things and quickly become unable to estimate the state and condition of the reservoir (fluid, pressures, faults etc) or oilfield hardware (wells, platforms, pumps) to make a sound next decision in the chain of reservoir management. Our modeling capabilities are such that if we know true state of the things - we can make incredibly accurate predictions and make extremely efficient decisions. Thus the bottleneck is our inability to properly describe the state of the reservoirs in real time. Industry is starting to recognize active monitoring as an answer to this critical issue. We will highlight industry strides in active geophysical monitoring from well to reservoir scale. It is worth noting that when one says ``monitoring" production technologists think of measuring pressures at the wellhead or at the pump, reservoir engineers think of measuring extracted volumes and pressures, while geophysicist may think of change in elastic properties. We prefer to think of monitoring as to measuring those parameters of the

  11. GAS HYDRATES AT TWO SITES OF AN ACTIVE CONTINENTAL MARGIN.

    USGS Publications Warehouse

    Kvenvolden, K.A.

    1985-01-01

    Sediment containing gas hydrates from two distant Deep Sea Drilling Project sites (565 and 568), located about 670 km apart on the landward flank of the Middle America Trench, was studied to determine the geochemical conditions that characterize the occurrence of gas hydrates. Site 565 was located in the Pacific Ocean offshore the Nicoya Peninsula of Costa Rica in 3,111 m of water. The depth of the hole at this site was 328 m, and gas hydrates were recovered from 285 and 319 m. Site 568 was located about 670 km to the northwest offshore Guatemala in 2,031 m of water. At this site the hole penetrated to 418 m, and gas hydrates were encountered at 404 m.

  12. Managing oil and gas activities in coastal environments: refuge manual

    SciTech Connect

    Longley, W.L.; Jackson, R.; Snyder, B.

    1981-09-01

    A study was undertaken to determine the impacts of all aspects of oil and gas development upon coastal ecological systems and to assess the safeguards used in protecting refuge lands. Wildlife refuges along the coasts of Texas and Louisiana were selected for intensive study. These refuges were characterized by (1) a diversity of ecosystems, (2) oil exploration, extraction, and transport, and (3) oil and gas development periods of varying durations.

  13. Preparation of activated carbon from waste plastics polyethylene terephthalate as adsorbent in natural gas storage

    NASA Astrophysics Data System (ADS)

    Yuliusman; Nasruddin; Sanal, A.; Bernama, A.; Haris, F.; Ramadhan, I. T.

    2017-02-01

    The main problem is the process of natural gas storage and distribution, because in normal conditions of natural gas in the gas phase causes the storage capacity be small and efficient to use. The technology is commonly used Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG). The weakness of this technology safety level is low because the requirement for high-pressure CNG (250 bar) and LNG requires a low temperature (-161°C). It takes innovation in the storage of natural gas using the technology ANG (Adsorbed Natural Gas) with activated carbon as an adsorbent, causing natural gas can be stored in a low pressure of about 34.5. In this research, preparation of activated carbon using waste plastic polyethylene terephthalate (PET). PET plastic waste is a good raw material for making activated carbon because of its availability and the price is a lot cheaper. Besides plastic PET has the appropriate characteristics as activated carbon raw material required for the storage of natural gas because the material is hard and has a high carbon content of about 62.5% wt. The process of making activated carbon done is carbonized at a temperature of 400 ° C and physical activation using CO2 gas at a temperature of 975 ° C. The parameters varied in the activation process is the flow rate of carbon dioxide and activation time. The results obtained in the carbonization process yield of 21.47%, while the yield on the activation process by 62%. At the optimum process conditions, the CO2 flow rate of 200 ml/min and the activation time of 240 minutes, the value % burn off amounted to 86.69% and a surface area of 1591.72 m2/g.

  14. Computer controlled vent and pressurization system

    NASA Technical Reports Server (NTRS)

    Cieslewicz, E. J.

    1975-01-01

    The Centaur space launch vehicle airborne computer, which was primarily used to perform guidance, navigation, and sequencing tasks, was further used to monitor and control inflight pressurization and venting of the cryogenic propellant tanks. Computer software flexibility also provided a failure detection and correction capability necessary to adopt and operate redundant hardware techniques and enhance the overall vehicle reliability.

  15. Preoperational test report, vent building ventilation system

    SciTech Connect

    Clifton, F.T.

    1997-11-04

    This represents a preoperational test report for Vent Building Ventilation Systems, Project W-030. Project W-030 provides a ventilation upgrade for the four Aging Waste Facility tanks. The system provides Heating, Ventilation, and Air Conditioning (HVAC) for the W-030 Ventilation Building. The tests verify correct system operation and correct indications displayed by the central Monitor and Control System.

  16. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  17. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  18. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  19. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  20. 46 CFR 98.25-70 - Venting.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Venting. 98.25-70 Section 98.25-70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in Bulk §...

  1. 40 CFR 63.1408 - Aggregate batch vent stream provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Aggregate batch vent stream provisions... § 63.1408 Aggregate batch vent stream provisions. (a) Emission standards. Owners or operators of aggregate batch vent streams at a new or existing affected source shall comply with either paragraph...

  2. 40 CFR 63.1408 - Aggregate batch vent stream provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Aggregate batch vent stream provisions... § 63.1408 Aggregate batch vent stream provisions. (a) Emission standards. Owners or operators of aggregate batch vent streams at a new or existing affected source shall comply with either paragraph...

  3. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... ventilation shall be installed within a horizontal distance of not more than ten feet from the vertical...

  4. 24 CFR 3280.710 - Venting, ventilation and combustion air.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Venting, ventilation and combustion... Fuel Burning Systems § 3280.710 Venting, ventilation and combustion air. (a) The venting as required by... ventilation shall be installed within a horizontal distance of not more than ten feet from the vertical...

  5. 46 CFR 182.450 - Vent pipes for fuel tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Vent pipes for fuel tanks. 182.450 Section 182.450... TONS) MACHINERY INSTALLATION Specific Machinery Requirements § 182.450 Vent pipes for fuel tanks. (a) Each unpressurized fuel tank must be fitted with a vent pipe connected to the highest point of the...

  6. 14 CFR 27.975 - Fuel tank vents.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fuel tank vents. 27.975 Section 27.975... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Fuel System § 27.975 Fuel tank vents. (a) Each fuel tank... system must be designed to minimize spillage of fuel through the vents to an ignition source in the...

  7. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  8. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  9. 40 CFR 63.1406 - Reactor batch process vent provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Reactor batch process vent provisions... § 63.1406 Reactor batch process vent provisions. (a) Emission standards. Owners or operators of reactor... reactor batch process vent located at a new affected source shall control organic HAP emissions...

  10. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Vent system discharges. 153.463 Section 153.463 Shipping... Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting system must be at least 10 m (approx. 32.8 ft) from an ignition source if: (a) The cargo tank is...

  11. 46 CFR 153.463 - Vent system discharges.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Vent system discharges. 153.463 Section 153.463 Shipping... Requirements for Flammable Or Combustible Cargoes § 153.463 Vent system discharges. The discharge of a venting system must be at least 10 m (approx. 32.8 ft) from an ignition source if: (a) The cargo tank is...

  12. 40 CFR 63.1429 - Process vent monitoring requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 11 2011-07-01 2011-07-01 false Process vent monitoring requirements....1429 Process vent monitoring requirements. (a) Monitoring equipment requirements. The owner or operator... vent control requirements in § 63.1425(b)(1), (b)(2), (c)(1), (c)(3), or (d) shall install...

  13. 40 CFR 63.1429 - Process vent monitoring requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 11 2010-07-01 2010-07-01 true Process vent monitoring requirements....1429 Process vent monitoring requirements. (a) Monitoring equipment requirements. The owner or operator... vent control requirements in § 63.1425(b)(1), (b)(2), (c)(1), (c)(3), or (d) shall install...

  14. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  15. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  16. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  17. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  18. 40 CFR 264.1032 - Standards: Process vents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Process vents. 264.1032 Section 264.1032 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES... Air Emission Standards for Process Vents § 264.1032 Standards: Process vents. (a) The owner...

  19. 33 CFR 183.520 - Fuel tank vent systems.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Fuel tank vent systems. 183.520...) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Fuel Systems Equipment Standards § 183.520 Fuel tank vent systems. (a) Each fuel tank must have a vent system that prevents pressure in the tank from exceeding...

  20. Evidence for Hydrothermal Vents as "Biogeobatteries" (Invited)

    NASA Astrophysics Data System (ADS)

    Nielsen, M. E.; Girguis, P. R.

    2010-12-01

    Hydrothermal vents are unique systems that play an important role in oceanic biogeochemical cycles. As chemically reduced hydrothermal fluid mixes with cold oxic seawater, minerals precipitate out of solution resulting in chimney structures composed largely of metal sulfides and anhydrite. Pyrite, which is a natural semi-conductor, is the primary sulfide mineral, but other minerals within chimneys are also conductive (e.g. chalcopyrite, wurtzite, and some iron oxides). Sulfide chimneys are also known to host an extensive endolithic microbial community. Accordingly, submarine hydrothermal systems appear to be examples of biogeobatteries, wherein conductive mineral assemblages span naturally occuring redox gradients and enable anaerobic microbes to access oxygen as an oxidant via extracellular electron transfer (or EET). To test this hypothesis, we ran a series of electrochemical laboratory experiments in which pyrite was used as an anode (in a vessel flushed with hydrothermal-like fluid). When placed in continuity with a carbon fiber cathode, pyrite was found to accept and conduct electrons from both abiotic and biological processes (microbial EET). Specifically, electrical current increased 4-fold (5 nA/m2 to 20 nA/m2) in response to inoculation with a slurry prepared from a hydrothermal vent sample. Inspection of the pyrite anode with SEM revealed ubiquitous coverage by microbes. DNA was extracted from the anodes and the inoculum, and was subjected to pyrosequencing to examine prokaryotic diversity. These data suggest that key microbial phylotypes were enriched upon the pyrite, implicating them in EET. In addition, we deployed an in situ experiment based on microbial fuel cell architecture with a graphite anode inserted into a vent wall coupled to a carbon fiber cathode outside the vent. We observed current production over the course of one year, implying microbial EET in situ. Via pyrosequencing, we observed that the microbial community on the anode was

  1. Impacts of anthropogenic disturbances at deep-sea hydrothermal vent ecosystems: a review.

    PubMed

    Van Dover, Cindy Lee

    2014-12-01

    Deep-sea hydrothermal-vent ecosystems have stimulated decades of scientific research and hold promise of mineral and genetic resources that also serve societal needs. Some endemic taxa thrive only in vent environments, and vent-associated organisms are adapted to a variety of natural disturbances, from tidal variations to earthquakes and volcanic eruptions. In this paper, physicochemical and biological impacts of a range of human activities at vents are considered. Mining is currently the only anthropogenic activity projected to have a major impact on vent ecosystems, albeit at a local scale, based on our current understanding of ecological responses to disturbance. Natural recovery from a single mining event depends on immigration and larval recruitment and colonization; understanding processes and dynamics influencing life-history stages may be a key to effective minimization and mitigation of mining impacts. Cumulative impacts on benthic communities of several mining projects in a single region, without proper management, include possible species extinctions and shifts in community structure and function.

  2. Degrading permafrost and gas hydrate under the Beaufort Shelf and marine gas hydrate on the adjacent continental slope

    NASA Astrophysics Data System (ADS)

    Paull, C. K.; Dallimore, S. R.; Hughes Clarke, J. E.; Blasco, S.; Melling, H.; Lundsten, E.; Vagle, S.; Collett, T. S.

    2011-12-01

    methane is occurring over a large area along the shelf edge. The methane gas emanating from both shelf features have stable isotopic compositions that indicate they are microbial in origin and are radiocarbon dead and thus sourced from geologic deposits. The PLF vents are believed to be sourced from the top of the gas hydrate stability field, while the gas emanating along the shelf edge can be from either permafrost or gas hydrate decomposition. Gas venting from both these shelf edge environments is consistent with heating associated with the last transgression. On the continental slope 3 circular topographic features up to 1 km in diameter occur in 290-790 m water depth. Data will be presented that show these are coincident with gas chimneys connected to geologic structures at depth. Water column flares, vigorous methane release and pore water freshening in cores suggest these are active vent sites and contain near seafloor marine gas hydrate. In this one area where both permafrost and marine gas hydrate occur in close proximity there is a remarkable coalescence of geologic features that are potentially related to climatically induced gas hydrate or permafrost decomposition.

  3. Low pressure storage of natural gas on activated carbon

    NASA Astrophysics Data System (ADS)

    Wegrzyn, J.; Wiesmann, H.; Lee, T.

    The introduction of natural gas to the transportation energy sector offers the possibility of displacing imported oil with an indigenous fuel. The barrier to the acceptance of natural gas vehicles (NGV) is the limited driving range due to the technical difficulties of on-board storage of a gaseous fuel. In spite of this barrier, compressed natural gas (CNG) vehicles are today being successfully introduced into the market place. The purpose of this work is to demonstrate an adsorbent natural gas (ANG) storage system as a viable alternative to CNG storage. It can be argued that low pressure ANG has reached near parity with CNG, since the storage capacity of CNG (2400 psi) is rated at 190 V/V, while low pressure ANG (500 psi) has reached storage capacities of 180 V/V in the laboratory. A program, which extends laboratory results to a full-scale vehicle test, is necessary before ANG technology will receive widespread acceptance. The objective of this program is to field test a 150 V/V ANG vehicle in FY 1994. As a start towards this goal, carbon adsorbents have been screened by Brookhaven for their potential use in a natural gas storage system. This paper reports on one such carbon, trade name Maxsorb, manufactured by Kansai Coke under an Amoco license.

  4. Zero-G Thermodynamic Venting System (TVS) Performance Prediction Program

    NASA Technical Reports Server (NTRS)

    Nguyen, Han

    1994-01-01

    This report documents the Zero-g Thermodynamic Venting System (TVS) performance prediction computer program. The zero-g TVS is a device that destratifies and rejects environmentally induced zero-g thermal gradients in the LH2 storage transfer system. A recirculation pump and spray injection manifold recirculates liquid throughout the length of the tank thereby destratifying both the ullage gas and liquid bulk. Heat rejection is accomplished by the opening of the TVS control valve which allows a small flow rate to expand to a low pressure thereby producing a low temperature heat sink which is used to absorb heat from the recirculating liquid flow. The program was written in FORTRAN 77 language on the HP-9000 and IBM PC computers. It can be run on various platforms with a FORTRAN compiler.

  5. Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

    USGS Publications Warehouse

    Flores, Gilberto E.; Campbell, James H.; Kirshtein, Julie D.; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua I.; Seewald, Jeffrey S.; Tivey, Margaret Kingston; Voytek, Mary A.; Yang, Zamin K.; Reysenbach, Anna-Louise

    2011-01-01

    To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

  6. Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge

    SciTech Connect

    Flores, Gilberto E; Campbell, James H; Kirshtein, Julie D; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua; Seewald, Jeffrey S; Tivey, Margaret Kingston; Voytek, Mary A; Reysenbach, Anna-Louise; Yang, Zamin Koo

    2011-01-01

    To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (37 17'N, 32 16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36 13'N, 33 54.1'W, depth 2270-2330 m) vent fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different vent fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

  7. Characteristics of puffing activity revealed by ground-based, thermal infrared imaging: the example of Stromboli Volcano (Italy)

    NASA Astrophysics Data System (ADS)

    Gaudin, Damien; Taddeucci, Jacopo; Scarlato, Piergiorgio; Harris, Andrew; Bombrun, Maxime; Del Bello, Elisabetta; Ricci, Tullio

    2017-03-01

    Puffing, i.e., the frequent (1 s ca.) release of small (0.1-10 m3), over-pressurized pockets of magmatic gases, is a typical feature of open-conduit basaltic volcanoes worldwide. Despite its non-trivial contribution to the degassing budget of these volcanoes and its recognized role in volcano monitoring, detection and metering tools for puffing are still limited. Taking advantage of the recent developments in high-speed thermal infrared imaging, we developed a specific processing algorithm to detect the emission of individual puffs and measure their duration, size, volume, and apparent temperature at the vent. As a test case, we applied our method at Stromboli Volcano (Italy), studying "snapshots" of 1 min collected in the years 2012, 2013, and 2014 at several vents. In all 3 years, puffing occurred simultaneously at three or more vents with variable features. At the scale of the single vent, a direct relationship links puff temperature and radius, suggesting that the apparent temperature is mostly a function of puff thickness, while the real gas temperature is constant for all puffs. Once released in the atmosphere, puffs dissipate in less than 20 m. On a broader scale, puffing activity is highly variable from vent to vent and year to year, with a link between average frequency, temperature, and volume from 136 puffs per minute, 600 K above ambient temperature, 0.1 m3, and the occasional ejection of pyroclasts to 20 puffs per minute, 3 K above ambient, 20 m3, and no pyroclasts. Frequent, small, hot puffs occur at random intervals, while as the frequency decreases and size increases, an increasingly longer minimum interval between puffs, up to 0.5 s, appears. These less frequent and smaller puffs also display a positive correlation between puff volume and the delay from the previous puff. Our results suggest an important role of shallow bubble coalescence in controlling puffing activity. The smaller and more frequent puffing at "hotter" vents is in agreement with

  8. Effects of Globally Waste Disturbing Activities on Gas Generation, Retention, and Release in Hanford Waste Tanks

    SciTech Connect

    Stewart, Charles W.; Fountain, Matthew S.; Huckaby, James L.; Mahoney, Lenna A.; Meyer, Perry A.; Wells, Beric E.

    2005-08-02

    Various operations are authorized in Hanford single- and double-shell tanks that disturb all or a large fraction of the waste. These globally waste-disturbing activities have the potential to release a large fraction of the retained flammable gas and to affect future gas generation, retention, and release behavior. This report presents analyses of the expected flammable gas release mechanisms and the potential release rates and volumes resulting from these activities. The background of the flammable gas safety issue at Hanford is summarized, as is the current understanding of gas generation, retention, and release phenomena. Considerations for gas monitoring and assessment of the potential for changes in tank classification and steady-state flammability are given.

  9. The effects of venting and decompression on Yellow Tang (Zebrasoma flavescens) in the marine ornamental aquarium fish trade

    PubMed Central

    Tissot, Brian N.; Heidel, Jerry R.; Miller-Morgan, Tim

    2015-01-01

    Each year, over 45 countries export 30 million fish from coral reefs as part of the global marine ornamental aquarium trade. This catch volume is partly influenced by collection methods that cause mortality. Barotrauma in fish resulting from forced ascent from depth can contribute to post-collection mortality. However, implementing decompression stops during ascent can prevent barotrauma. Conversely, venting (puncturing the swim bladder to release expanded internal gas) following ascent can mitigate some signs of barotrauma like positive buoyancy. Here, we evaluate how decompression and venting affect stress and mortality in the Yellow Tang (Zebrasoma flavescens). We examined the effects of three ascent treatments, each with decompression stops of varying frequency and duration, coupled with or without venting, on sublethal effects and mortality using histology and serum cortisol measurements. In fish subjected to ascent without decompression stops or venting, a mean post-collection mortality of 6.2% occurred within 24 h of capture. Common collection methods in the fishery, ascent without decompression stops coupled with venting, or one long decompression stop coupled with venting, resulted in no mortality. Histopathologic examination of heart, liver, head kidney, and swim bladder tissues in fish 0d and 21d post-collection revealed no significant barotrauma- or venting-related lesions in any treatment group. Ascent without decompression stops resulted in significantly higher serum cortisol than ascent with many stops, while venting alone did not affect cortisol. Future work should examine links in the supply chain following collection to determine if further handling and transport stressors affect survivorship and sublethal effects. PMID:25737809

  10. Gas cleaning and hydrogen sulfide removal for COREX coal gas by sorption enhanced catalytic oxidation over recyclable activated carbon desulfurizer.

    PubMed

    Sun, Tonghua; Shen, Yafei; Jia, Jinping

    2014-02-18

    This paper proposes a novel self-developed JTS-01 desulfurizer and JZC-80 alkaline adsorbent for H2S removal and gas cleaning of the COREX coal gas in small-scale and commercial desulfurizing devices. JTS-01 desulfurizer was loaded with metal oxide (i.e., ferric oxides) catalysts on the surface of activated carbons (AC), and the catalyst capacity was improved dramatically by means of ultrasonically assisted impregnation. Consequently, the sulfur saturation capacity and sulfur capacity breakthrough increased by 30.3% and 27.9%, respectively. The whole desulfurizing process combined selective adsorption with catalytic oxidation. Moreover, JZC-80 adsorbent can effectively remove impurities such as HCl, HF, HCN, and ash in the COREX coal gas, stabilizing the system pressure drop. The JTS-01 desulfurizer and JZC-80 adsorbent have been successfully applied for the COREX coal gas cleaning in the commercial plant at Baosteel, Shanghai. The sulfur capacity of JTS-01 desulfurizer can reach more than 50% in industrial applications. Compared with the conventional dry desulfurization process, the modified AC desulfurizers have more merit, especially in terms of the JTS-01 desulfurizer with higher sulfur capacity and low pressure drop. Thus, this sorption enhanced catalytic desulfurization has promising prospects for H2S removal and other gas cleaning.

  11. Moving in extreme environments: inert gas narcosis and underwater activities.

    PubMed

    Clark, James E

    2015-01-01

    Exposure to the underwater environment for pleasure or work poses many challenges on the human body including thermal stress, barotraumas, decompression sickness as well as the acute effects of breathing gases under pressure. With the popularity of recreational self-contained underwater breathing apparatus (SCUBA) diving on the increase and deep inland dive sites becoming more accessible, it is important that we understand the effects of breathing pressurised gas at depth can have on the body. One of the common consequences of hyperbaric gas is the narcotic effect of inert gas. Nitrogen (a major component of air) under pressure can impede mental function and physical performance at depths of as little as 10 m underwater. With increased depth, symptoms can worsen to include confusion, disturbed coordination, lack of concentration, hallucinations and unconsciousness. Narcosis has been shown to contribute directly to up to 6% of deaths in divers and is likely to be indirectly associated with other diving incidents at depth. This article explores inert gas narcosis, the effect on divers' movement and function underwater and the proposed physiological mechanisms. Also discussed are some of the factors that affect the susceptibility of divers to the condition. In conclusion, understanding the cause of this potentially debilitating problem is important to ensure that safe diving practices continue.

  12. Niche partitioning of diverse sulfur-oxidizing bacteria at hydrothermal vents.

    PubMed

    Meier, Dimitri V; Pjevac, Petra; Bach, Wolfgang; Hourdez, Stephane; Girguis, Peter R; Vidoudez, Charles; Amann, Rudolf; Meyerdierks, Anke

    2017-04-04

    At deep-sea hydrothermal vents, primary production is carried out by chemolithoautotrophic microorganisms, with the oxidation of reduced sulfur compounds being a major driver for microbial carbon fixation. Dense and highly diverse assemblies of sulfur-oxidizing bacteria (SOB) are observed, yet the principles of niche differentiation between the different SOB across geochemical gradients remain poorly understood. In this study niche differentiation of the key SOB was addressed by extensive sampling of active sulfidic vents at six different hydrothermal venting sites in the Manus Basin, off Papua New Guinea. We subjected 33 diffuse fluid and water column samples and 23 samples from surfaces of chimneys, rocks and fauna to a combined analysis of 16S rRNA gene sequences, metagenomes and real-time in situ measured geochemical parameters. We found Sulfurovum Epsilonproteobacteria mainly attached to surfaces exposed to diffuse venting, while the SUP05-clade dominated the bacterioplankton in highly diluted mixtures of vent fluids and seawater. We propose that the high diversity within Sulfurimonas- and Sulfurovum-related Epsilonproteobacteria observed in this study derives from the high variation of environmental parameters such as oxygen and sulfide concentrations across small spatial and temporal scales.The ISME Journal advance online publication, 4 April 2017; doi:10.1038/ismej.2017.37.

  13. Spatial Compilation of Holocene Volcanic Vents in the Western Conterminous United States

    NASA Astrophysics Data System (ADS)

    Ramsey, D. W.; Siebert, L.

    2015-12-01

    A spatial compilation of all known Holocene volcanic vents in the western conterminous United States has been assembled. This compilation records volcanic vent location (latitude/longitude coordinates), vent type (cinder cone, dome, etc.), geologic map unit description, rock type, age, numeric age and reference (if dated), geographic feature name, mapping source, and, where available, spatial database source. Primary data sources include: USGS geologic maps, USGS Data Series, the Smithsonian Global Volcanism Program (GVP) catalog, and published journal articles. A total of 726 volcanic vents have been identified from 45 volcanoes or volcanic fields spanning ten states. These vents are found along the length of the Cascade arc in the Pacific Northwest, widely around the Basin and Range province, and at the southern margin of the Colorado Plateau into New Mexico. The U.S. Geological Survey (USGS) National Volcano Early Warning System (NVEWS) identifies 28 volcanoes and volcanic centers in the western conterminous U.S. that pose moderate, high, or very high threats to surrounding communities based on their recent eruptive histories and their proximity to vulnerable people, property, and infrastructure. This compilation enhances the understanding of volcano hazards that could threaten people and property by providing the context of where Holocene eruptions have occurred and where future eruptions may occur. Locations in this compilation can be spatially compared to located earthquakes, used as generation points for numerical hazard models or hazard zonation buffering, and analyzed for recent trends in regional volcanism and localized eruptive activity.

  14. The Origin of Life in Alkaline Hydrothermal Vents.

    PubMed

    Sojo, Victor; Herschy, Barry; Whicher, Alexandra; Camprubí, Eloi; Lane, Nick

    2016-02-01

    Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea.

  15. 75 FR 70021 - Environmental Documents Prepared in Support of Oil and Gas Activities on the Alaska Outer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-16

    ... of Oil and Gas Activities on the Alaska Outer Continental Shelf AGENCY: Bureau of Ocean Energy... (FONSI) prepared for two oil and gas activities proposed on the Alaska Outer Continental Shelf (OCS)...

  16. Implementing an Inexpensive and Accurate Introductory Gas Density Activity with High School Students

    ERIC Educational Resources Information Center

    Cunningham, W. Patrick; Joseph, Christopher; Morey, Samantha; Santos Romo, Ana; Shope, Cullen; Strang, Jonathan; Yang, Kevin

    2015-01-01

    A simplified activity examined gas density while employing cost-efficient syringes in place of traditional glass bulbs. The exercise measured the density of methane, with very good accuracy and precision, in both first-year high school and AP chemistry settings. The participating students were tasked with finding the density of a gas. The…

  17. 78 FR 76827 - Midwestern Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-19

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Midwestern Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate On December 4, 2013, Midwestern Gas Transmission Company (Midwestern) filed with the Federal Energy Regulatory Commission...

  18. GAS PHASE SELECTIVE PHOTOXIDATION OF ALCOHOLS USING LIGHT-ACTIVATED TITANIUM DIOXIDE AND MOLECULAR OXYGEN

    EPA Science Inventory

    Gas Phase Selective Oxidation of Alcohols Using Light-Activated Titanium Dioxide and Molecular Oxygen

    Gas phase selective oxidations of various primary and secondary alcohols are studied in an indigenously built stainless steel up-flow photochemical reactor using ultravi...

  19. Emission factors for hydraulically fractured gas wells derived using well- and battery-level reported data for Alberta, Canada.

    PubMed

    Tyner, David R; Johnson, Matthew R

    2014-12-16

    A comprehensive technical analysis of available industry-reported well activity and production data for Alberta in 2011 has been used to derive flaring, venting, and diesel combustion greenhouse gas and criteria air contaminant emission factors specifically linked to drilling, completion, and operation of hydraulically fractured natural gas wells. Analysis revealed that in-line ("green") completions were used at approximately 53% of wells completed in 2011, and in other cases the majority (99.5%) of flowback gases were flared rather than vented. Comparisons with limited analogous data available in the literature revealed that reported total flared and vented natural gas volumes attributable to tight gas well-completions were ∼ 6 times larger than Canadian Association of Petroleum Producers (CAPP) estimates for natural gas well-completion based on wells ca. 2000, but 62% less than an equivalent emission factor that can be derived from U.S. EPA data. Newly derived emission factors for diesel combustion during well drilling and completion are thought to be among the first such data available in the open literature, where drilling-related emissions for tight gas wells drilled in Alberta in 2011 were found to have increased by a factor of 2.8 relative to a typical well drilled in Canada in 2000 due to increased drilling lengths. From well-by-well analysis of production phase flared, vented, and fuel usage natural gas volumes reported at 3846 operating tight gas wells in 2011, operational emission factors were developed. Overall results highlight the importance of operational phase GHG emissions at upstream well sites (including on-site natural gas fuel use), and the critical levels of uncertainty in current estimates of liquid unloading emissions.

  20. Vent evolution and lag breccia formation during the Cape Riva eruption of Santorini, Greece.

    USGS Publications Warehouse

    Druitt, T.H.

    1985-01-01

    The 18 500 yr BP Cape Riva (CR) eruption of Santorini vented several km3 or more of magma, generating 4 eruption units, each of which is discussed. The eruption sampled a zoned magma chamber containing rhyodacite overlying andesite, and leaks of these magmas were manifested as the Skaros-Therasia lavas preceding the CR eruption. Plinian and initial ignimbrite stages occurred while the magma chamber was overpressured; subsequent underpressuring, due to magma discharge, caused fracturing of the chamber roof, caldera collapse, and eruption of pyroclastic flows from multiple vents. Activation and widening of new conduits during collapse resulted in the rapid escalation of discharge rate favoring the formation of lag breccias by: 1) promoting erosion of lithic debris at the surface vent; and 2) raising surface exit pressures, thereby resulting in a dramatic increase in the grain size of the ejecta.-from Author

  1. Provisions for containment venting in Germany

    SciTech Connect

    Wilhelm, J.G.

    1997-08-01

    In this short paper an overlook is given of the systems developed in Germany for filtered containment venting and their implementation in nuclear power plants. More information on the development can be found in the Proceedings of the DOE/NRC Aircleaning Conferences. In Germany, 28.8 % of the electric energy is produced by 19 nuclear power reactors. No new power reactor is expected to be built at least within the next ten years, but France and Germany cooperate in the development of a future European Power Reactor (ERP). This reactor type will be fitted with a core catcher and passive cooling in order to avoid serious consequences of a hypothetical core meltdown accident so that provisions for containment venting are not required. 3 refs., 6 figs., 1 tab.

  2. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... authorize cargo discharge by gas pressurization unless: (a) The tank to be offloaded has an SR or PV venting system; (b) The pressurization medium is either the cargo vapor or a nonflammable, nontoxic gas inert...

  3. 46 CFR 153.964 - Discharge by gas pressurization.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... authorize cargo discharge by gas pressurization unless: (a) The tank to be offloaded has an SR or PV venting system; (b) The pressurization medium is either the cargo vapor or a nonflammable, nontoxic gas inert...

  4. A conduit dilation model of methane venting from lake sediments

    USGS Publications Warehouse

    Scandella, B.P.; Varadharajan, C.; Hemond, Harold F.; Ruppel, C.; Juanes, R.

    2011-01-01

    Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

  5. A conduit dilation model of methane venting from lake sediments

    NASA Astrophysics Data System (ADS)

    Scandella, Benjamin P.; Varadharajan, Charuleka; Hemond, Harold F.; Ruppel, Carolyn; Juanes, Ruben

    2011-03-01

    Methane is a potent greenhouse gas, but its effects on Earth's climate remain poorly constrained, in part due to uncertainties in global methane fluxes to the atmosphere. An important source of atmospheric methane is the methane generated in organic-rich sediments underlying surface water bodies, including lakes, wetlands, and the ocean. The fraction of the methane that reaches the atmosphere depends critically on the mode and spatiotemporal characteristics of free-gas venting from the underlying sediments. Here we propose that methane transport in lake sediments is controlled by dynamic conduits, which dilate and release gas as the falling hydrostatic pressure reduces the effective stress below the tensile strength of the sediments. We test our model against a four-month record of hydrostatic load and methane flux in Upper Mystic Lake, Mass., USA, and show that it captures the complex episodicity of methane ebullition. Our quantitative conceptualization opens the door to integrated modeling of methane transport to constrain global methane release from lakes and other shallow-water, organic-rich sediment systems, and to assess its climate feedbacks.

  6. Sparger system for MMH-helium vents

    NASA Technical Reports Server (NTRS)

    Rakow, A.

    1983-01-01

    Based on a calculated vent flow rate and MMH concentration, a TI-59 program was run to determine total sparger hole area for a given sparger inlet pressure. Hole diameter is determined from a mass transfer analysis in the holding tank to achieve complete capture of MMH. In addition, based on oxidation kinetics and vapor pressure data, MMh atmospheric concentrations are determined 2 ft above the holding tank.

  7. Elevating salinity and temperature with hydrate formation at deepwater Gulf of Mexico vents

    NASA Astrophysics Data System (ADS)

    Smith, Andrew J.; Flemings, Peter B.; Liu, Xiaoli

    2013-04-01

    We study the Ursa vent in ~1070 meters water depth at lease blocks MC852/853 in the northern Gulf of Mexico. Elevated salinities and temperatures at the vent shift the base of the hydrate stability zone (HSZ) to the seafloor (Paull et al., 2005; Ruppel et al., 2005). We model the coexistence of high salinities, high temperatures, and an uplifted hydrate phase boundary with a one-dimensional, multicomponent, multiphase, fluid- and heat-flow model of hydrate formation. In this model, free gas supplied from depth migrates vertically through a high-permeability conduit to the regional hydrate stability zone (RHSZ). Once reaching the base of the RHSZ, gas combines with water to form hydrate, salt is excluded, and heat is released. Hydrate formation continues until water is too warm and saline for further hydrate formation. This process self generates three-phase (gas, liquid, hydrate) equilibrium through the RHSZ and allows gas to vent from the base of the RHSZ to the seafloor. Once the reaction front breaches the seafloor, a pseudo steady state is reached in which a continuous salt flux diffuses from the seafloor, and further hydrate formation occurs at a rate necessary to replace the diffuse salt loss. This continued hydrate formation has the potential to produce large, steady fluxes of salt and heat from the seafloor. Such gas-hydrate and fluid-flow systems are important because they are especially sensitive to global ocean warming due to the large concentrations of hydrate that exist at three-phase equilibrium near the seafloor. References: Paull, C., Ussler, W., Lorenson, T., Winters, W., Dougherty, J., 2005. Geochemical constraints on the distribution of gas hydrates in the Gulf of Mexico. Geo-Marine Letters 25, 273-280. Ruppel, C., Dickens, G.R., Castellini, D.G., Gilhooly, W., Lizarralde, D., 2005. Heat and salt inhibition of gas hydrate formation in the northern Gulf of Mexico. Geophys. Res. Lett. 32, L04605.

  8. Comparative Study of Vented vs. Unvented Crawlspaces

    SciTech Connect

    Biswas, Kaushik; Christian, Jeffrey E; Gehl, Anthony C

    2011-10-01

    There has been a significant amount of research in the area of building energy efficiency and durability. However, well-documented quantitative information on the impact of crawlspaces on the performance of residential structures is lacking. The objective of this study was to evaluate and compare the effects of two crawlspace strategies on the whole-house performance of a pair of houses in a mixed humid climate. These houses were built with advanced envelope systems to provide energy savings of 50% or more compared to traditional 2010 new construction. One crawlspace contains insulated walls and is sealed and semi-conditioned. The other is a traditional vented crawlspace with insulation in the crawlspace ceiling. The vented (traditional) crawlspace contains fiberglass batts installed in the floor chase cavities above the crawl, while the sealed and insulated crawlspace contains foil-faced polyisocyanurate foam insulation on the interior side of the masonry walls. Various sensors to measure temperatures, heat flux through crawlspace walls and ceiling, and relative humidity were installed in the two crawlspaces. Data from these sensors have been analyzed to compare the performance of the two crawlspace designs. The analysis results indicated that the sealed and insulated crawlspace design is better than the traditional vented crawlspace in the mixed humid climate.

  9. Colonization of nascent, deep-sea hydrothermal vents by a novel Archaeal and Nanoarchaeal assemblage.

    PubMed

    McCliment, Elizabeth A; Voglesonger, Kenneth M; O'Day, Peggy A; Dunn, Eileen E; Holloway, John R; Cary, S Craig

    2006-01-01

    Active deep-sea hydrothermal vents are areas of intense mixing and severe thermal and chemical gradients, fostering a biotope rich in novel hyperthermophilic microorganisms and metabolic pathways. The goal of this study was to identify the earliest archaeal colonizers of nascent hydrothermal chimneys, organisms that may be previously uncharacterized as they are quickly replaced by a more stable climax community. During expeditions in 2001 and 2002 to the hydrothermal vents of the East Pacific Rise (EPR) (9 degrees 50'N, 104 degrees 17'W), we removed actively venting chimneys and in their place deployed mineral chambers and sampling units that promoted the growth of new, natural hydrothermal chimneys and allowed their collection within hours of formation. These samples were compared with those collected from established hydrothermal chimneys from EPR and Guaymas Basin vent sites. Using molecular and phylogenetic analysis of the 16S rDNA, we show here that at high temperatures, early colonization of a natural chimney is dominated by members of the archaeal genus Ignicoccus and its symbiont, Nanoarchaeum. We have identified 19 unique sequences closely related to the nanoarchaeal group, and five archaeal sequences that group closely with Ignicoccus. These organisms were found to colonize a natural, high temperature protochimney and vent-like mineral assemblages deployed over high temperature outflows within 92 h. When compared phylogenetically, several of these colonizing organisms form a unique clade independent of those found in mature chimneys and low-temperature mineral chamber samples. As a model ecosystem, the identification of pioneering consortia in deep-sea hydrothermal vents may help advance the understanding of how early microbial life forms gained a foothold in hydrothermal systems on early Earth and potentially on other planetary bodies.

  10. A single-nanoparticle NO2 gas sensor constructed using active molecular plasmonics.

    PubMed

    Chen, Lichan; Wu, Bo; Guo, Longhua; Tey, Ruiwen; Huang, Youju; Kim, Dong-Hwan

    2015-01-25

    A single-nanoparticle plasmonic sensor for the sensitive detection of gas molecules (NO2) has been constructed. Taking advantage of active molecular plasmonics, the analyte selectively triggers a measurable spectral shift of ferrocene-modified single gold nanorods.

  11. Modelling the Composition of Outgassing Bubbles at Basaltic Open Vent Volcanoes

    NASA Astrophysics Data System (ADS)

    Edmonds, M.; Clements, N.; Houghton, B. F.; Oppenheimer, C.; Jones, R. L.; Burton, M. R.

    2015-12-01

    Basaltic open vent volcanoes exhibit a wide range in eruption styles, from passive outgassing to Strombolian and Hawaiian explosive activity. Transitions between these styles are linked to contrasting two-phase (melt and gas) flow regimes in the conduit system. A wealth of data now exists characterising the fluxes and compositions of gases emitted from these volcanoes, alongside detailed observations of patterns of outgassing at the magma free surfaces. Complex variations in gas composition are apparent from high temporal resolution measurement techniques such as open path spectroscopy. This variability with time is likely a function of individual bubbles' histories of growth during ascent, with variable degrees of kinetic inhibition. Our previous studies at Kilauea and Stromboli have, for example, linked CO2-rich gases with the bursting of bubbles that last equilibrated at some depth beneath the surface. However, very few studies have attempted to reconcile such observations with quantitative models of diffusion-limited bubble growth in magmas prior to eruption. We present here an analytical model that simulates the growth of populations of bubbles by addition of volatile mass during decompression, with growth limited by diffusion. The model simulates a range of behaviors between the end members of separated two-phase flow and homogeneous bubbly flow in the conduit, tied to thermodynamic models of solubility and partitioning of volatile species (carbon, water, sulfur). We explore the effects of the form of bubble populations at depth, melt viscosity, total volatile content, magma decompression rate and other intrinsic parameters on expected gas compositions at the surface and consider implications for transitions between eruption styles. We compare the the model to data suites from Stromboli and Kilauea.

  12. Small molecule inhibitors block Gas6-inducible TAM activation and tumorigenicity

    PubMed Central

    Kimani, Stanley G.; Kumar, Sushil; Bansal, Nitu; Singh, Kamalendra; Kholodovych, Vladyslav; Comollo, Thomas; Peng, Youyi; Kotenko, Sergei V.; Sarafianos, Stefan G.; Bertino, Joseph R.; Welsh, William J.; Birge, Raymond B.

    2017-01-01

    TAM receptors (Tyro-3, Axl, and Mertk) are a family of three homologous type I receptor tyrosine kinases that are implicated in several human malignancies. Overexpression of TAMs and their major ligand Growth arrest-specific factor 6 (Gas6) is associated with more aggressive staging of cancers, poorer predicted patient survival, acquired drug resistance and metastasis. Here we describe small molecule inhibitors (RU-301 and RU-302) that target the extracellular domain of Axl at the interface of the Ig-1 ectodomain of Axl and the Lg-1 of Gas6. These inhibitors effectively block Gas6-inducible Axl receptor activation with low micromolar IC50s in cell-based reporter assays, inhibit Gas6-inducible motility in Axl-expressing cell lines, and suppress H1299 lung cancer tumor growth in a mouse xenograft NOD-SCIDγ model. Furthermore, using homology models and biochemical verifications, we show that RU301 and 302 also inhibit Gas6 inducible activation of Mertk and Tyro3 suggesting they can act as pan-TAM inhibitors that block the interface between the TAM Ig1 ectodomain and the Gas6 Lg domain. Together, these observations establish that small molecules that bind to the interface between TAM Ig1 domain and Gas6 Lg1 domain can inhibit TAM activation, and support the further development of small molecule Gas6-TAM interaction inhibitors as a novel class of cancer therapeutics. PMID:28272423

  13. Self-Activated Transparent All-Graphene Gas Sensor with Endurance to Humidity and Mechanical Bending.

    PubMed

    Kim, Yeon Hoo; Kim, Sang Jin; Kim, Yong-Jin; Shim, Yeong-Seok; Kim, Soo Young; Hong, Byung Hee; Jang, Ho Won

    2015-10-27

    Graphene is considered as one of leading candidates for gas sensor applications in the Internet of Things owing to its unique properties such as high sensitivity to gas adsorption, transparency, and flexibility. We present self-activated operation of all graphene gas sensors with high transparency and flexibility. The all-graphene gas sensors which consist of graphene for both sensor electrodes and active sensing area exhibit highly sensitive, selective, and reversible responses to NO2 without external heating. The sensors show reliable operation under high humidity conditions and bending strain. In addition to these remarkable device performances, the significantly facile fabrication process enlarges the potential of the all-graphene gas sensors for use in the Internet of Things and wearable electronics.

  14. Applications for activated carbons from waste tires: Natural gas storage and air pollution control

    USGS Publications Warehouse

    Brady, T.A.; Rostam-Abadi, M.; Rood, M.J.

    1996-01-01

    Natural gas storage for natural gas vehicles and the separation and removal of gaseous contaminants from gas streams represent two emerging applications for carbon adsorbents. A possible precursor for such adsorbents is waste tires. In this study, activated carbon has been developed from waste tires and tested for its methane storage capacity and SO2 removal from a simulated flue-gas. Tire-derived carbons exhibit methane adsorption capacities (g/g) within 10% of a relatively expensive commercial activated carbon; however, their methane storage capacities (Vm/Vs) are almost 60% lower. The unactivated tire char exhibits SO2 adsorption kinetics similar to a commercial carbon used for flue-gas clean-up. Copyright ?? 1996 Elsevier Science Ltd.

  15. Biodiversity and biogeography of hydrothermal vent species in the western Pacific: a biological perspective of TAIGA project

    NASA Astrophysics Data System (ADS)

    Seo, M.; Watanabe, H.; Nakamura, M.; Sasaki, T.; Ogura, T.; Yahagi, T.; Takahashi, Y.; Ishibashi, J.; Kojima, S.

    2012-12-01

    Deep-sea hydrothermal vents are scientifically interesting environments where strong interactions of geology, chemistry, and biology can be observed. The hydrothermal vents are geologically controlled in association with magmatic activities while diversity of chemicals (such as hydrogen sulfide) contained in hydrothermal fluid is controlled by geochemical interaction between heated seawater and surrounding rocks. In addition to those geological and chemical characters of hydrothermal vents, high biomasses of chemosynthetic community have been known around many vents since the first discovery in the 1970s. To understand the unique system and diversity of biological communities associated with vents is highly valuable in geological, chemical, and biological sciences. As an activity of the research project "TAIGA (Trans-crustal Advection & In-situ bio-geochemical processes of Global sub-seafloor Aquifer)" (Representative: Tetsuro Urabe, Department of Earth & Planetary Science, the University of Tokyo), we analyzed population structures and connectivity as well as larval ecology of various hydrothermal vent species in the Okinawa Trough and the Mariana Trough in an attempt to estimate faunal transitional history associated with hydrothermal activities. The specimens analyzed in the present study were collected by R/V Yokosuka with manned submersible Shinkai6500 and R/V Natsushima with ROV Hyper-Dolphin during YK10-11 and NT11-20 cruises, respectively. In the Mariana Trough (YK10-11), benthic and planktonic faunas were investigated by multiple sampling and use of plankton samplers in three hydrothermal vents (Snail, Archaean, and Urashima-Pika fields). Faunal compositions were then compared as well as size compositions and genetic diversities of major vent species among local populations. In the Okinawa Trough (NT11-20), multiple quantitative sampling was made with simultaneous environmental measurements at more than two sites in five hydrothermal vents (Minami

  16. Implications of historical eruptive-vent migration on the northeast rift zone of Mauna Loa Volcano, Hawaii

    SciTech Connect

    Lockwood, J.P. )

    1990-07-01

    Five times within the past 138 yr (1852, 1855-1856, 1880-1881, 1942, and 1984), lava flows from vents on the northeast rift zone of Mauna Loa Volcano have reached within a few kilometres of Hilo (the largest city on the Island of Hawaii). Most lavas erupted on this right zone in historical time have traveled northeastward (toward Hilo), because their eruptive vents have been concentrated north of the rift zone's broad topographic axis. However, with few exceptions each successive historical eruption on the northeast rift zone has occurred farther southeast than the preceding one. Had the 1984 eruptive vents (the most southeasterly yet) opened less than 200 m farther southeast, the bulk of the 1984 lavas would have flowed away from Hilo. If this historical vent-migration pattern continues, the next eruption on the northeast rift zone could send lavas to the southeast, toward less populated areas. The historical Mauna Loa vent-migration patterns mimic southeastern younging of the Hawaiian-Emperor volcanic chain and may be cryptically related to northwestward movement of the Pacific plate. Systematic temporal-spatial vent-migration patterns may characterize eruptive activity at other volcanoes with flank activity and should be considered as an aid to long-term prediction of eruption sites.

  17. Hydrothermal fluids vented at shallow depths at the Aeolian islands: relationships with volcanic and geothermal systems.

    NASA Astrophysics Data System (ADS)

    Italiano, Francesco; Caracausi, Antonio; Longo, Manfredi; Maugeri, Roberto; Paonita, Antonio

    2010-05-01

    Scuba diving investigations carried out over the last two decades at the Aeolian islands revealed the existence of submarine magmatic and late-magmatic hydrothermalism at all the islands, despite the absence of on-shore activity at some of the islands. The results gained by diving activities provided useful information to evaluate the volcanic and geothermal activity and to manage the volcanic crisis occurred on November 2002 off the island of Panarea. Scuba diving investigations carried out from middle 80's, had shown that despite the absence of on shore volcanic manifestations, submarine hydrothermal activity is recognizable at shallow depth around all the Aeolian islands related either to volcanic and geothermal activity. The sampled gases are CO2-dominated with low amounts of oxygen and reactive gases (H2, CO, CH4 and H2S) with concentrations ranging from a few ppm to some mole percent. Sometimes significant N2 amount are detectable together with high helium contents. Samples having low CO2 content, besides relevant N2 and He amounts, are the consequence of CO2 dissolution in sea-water due to gas-water interactions (GWI) occurred before the sample collection. The high CO2 solubility (878 ml/l, T=20°C, P=1bar) may, in fact, decrease the CO2 content in the venting gases thus increasing the concentrations of the less soluble species (e.g. He 8 ml/l, CO 23 ml/l and CH4 33.8 ml/l) in the gas mixture. Such a process might occur at any level, however, because of the slow water circulation in deep sediments, CO2 is able to saturate the circulating sea-water. The isotopic composition of carbon displays a small range of values while helium isotopes are in the range of 4.1active and extinct Volcanoes, their chemical composition is similar. Contrastingly the isotope composition of helium shows a large heterogeneity with the highest isotopic ratios surprisingly measured at the extinct volcanic islands in the western sector, and much

  18. Advanced Gas Sensors Using SERS-Activated Waveguides

    NASA Astrophysics Data System (ADS)

    Lascola, Robert; McWhorter, Scott; Murph, Simona Hunyadi

    2010-08-01

    This contribution describes progress towards the development and testing of a functionalized capillary that will provide detection of low-concentration gas-phase analytes through SERS. Measurement inside a waveguide allows interrogation of a large surface area, potentially overcoming the short distance dependence of the SERS effect. The possible use of Raman spectroscopy for gas detection is attractive for IR-inactive molecules or scenarios where infrared technology is inconvenient. However, the weakness of Raman scattering limits the use of the technique to situations where low detection limits are not required or large gas pressures are present. With surface-enhanced Raman spectroscopy (SERS), signal enhancements of 106 are often claimed, and higher values are seen in specific instances. However, most of the examples of SERS analysis are on liquid-phase samples, where the molecular density is high, usually combined with some sort of sample concentration at the surface. Neither of these factors is present in gas-phase samples. Because the laser is focused to a small point in the typical experimental setup, and the spatial extent of the effect above the surface is small (microns), the excitation volume is miniscule. Thus, exceptionally large enhancements are required to generate a signal comparable to that obtained by conventional Raman measurements. A reflective waveguide offers a way to increase the interaction volume of the laser with a SERS-modified surface. The use of a waveguide to enhance classical Raman measurements was recently demonstrated by S.M. Angel and coworkers, who obtained 12- to 30-fold sensitivity improvements for nonabsorbing gases (CO2, CH4) with a silvered capillary (no SERS enhancement). Shi et al.. demonstrated 10-to 100-fold enhancement of aqueous Rhodamine 6G in a capillary coated with silver nanoparticles. They observed enhancements of 10- to 100-fold compared to direct sampling, but this relied on a "double substrate", which required

  19. Development of a practical training program based on BNL`s input to new NFPA Lined Masonary Chimney Venting Tables

    SciTech Connect

    Potter, G.

    1997-09-01

    This paper describes how we developed a practical training program for technicians and sales personnel from the BNL studies that evolved into the Lined Chimney Venting Tables. One of the topics discussed is our search for solutions to the reoccurring problems associated with flue gas condensation on newly installed oil fired appliances. The paper will also discuss our own experiences in applying the new venting tables and working through the questions that arise when we encounter installations beyond the scope of the present tables.

  20. Design improvement, qualification testing, purge and vent investigation, fabrication, and documentation of a GAC-9 insulation system

    NASA Technical Reports Server (NTRS)

    Shriver, C. B.; Apisa, J. N.; Kariotis, A. H.

    1971-01-01

    Results of the research and development program to determine the purge and vent characteristics of the GAC-9 insulation system are summarized. The work scope comprised: (1) literature survey; (2) design improvement and insulation effort; (3) testing; and (4) evaluation of test results. Program objectives to be realized are: (1) definition of purge gas flow characteristics of the GAC-9 insulation system through laboratory measurements; and (2) demonstration of insulation effectiveness as a system for prelaunch purging and launch venting of the 76-cm diameter calorimeter, which is a subscale model simulating a realistic type of GAC-9 insulation application.

  1. RNA Oligomerization in Laboratory Analogues of Alkaline Hydrothermal Vent Systems.

    PubMed

    Burcar, Bradley T; Barge, Laura M; Trail, Dustin; Watson, E Bruce; Russell, Michael J; McGown, Linda B

    2015-07-01

    Discovering pathways leading to long-chain RNA formation under feasible prebiotic conditions is an essential step toward demonstrating the viability of the RNA World hypothesis. Intensive research efforts have provided evidence of RNA oligomerization by using circular ribonucleotides, imidazole-activated ribonucleotides with montmorillonite catalyst, and ribonucleotides in the presence of lipids. Additionally, mineral surfaces such as borates, apatite, and calcite have been shown to catalyze the formation of small organic compounds from inorganic precursors (Cleaves, 2008 ), pointing to possible geological sites for the origins of life. Indeed, the catalytic properties of these particular minerals provide compelling evidence for alkaline hydrothermal vents as a potential site for the origins of life since, at these vents, large metal-rich chimney structures can form that have been shown to be energetically favorable to diverse forms of life. Here, we test the ability of iron- and sulfur-rich chimneys to support RNA oligomerization reactions using imidazole-activated and non-activated ribonucleotides. The chimneys were synthesized in the laboratory in aqueous "ocean" solutions under conditions consistent with current understanding of early Earth. Effects of elemental composition, pH, inclusion of catalytic montmorillonite clay, doping of chimneys with small organic compounds, and in situ ribonucleotide activation on RNA polymerization were investigated. These experiments, under certain conditions, showed successful dimerization by using unmodified ribonucleotides, with the generation of RNA oligomers up to 4 units in length when imidazole-activated ribonucleotides were used instead. Elemental analysis of the chimney precipitates and the reaction solutions showed that most of the metal cations that were determined were preferentially partitioned into the chimneys.

  2. Identification of possible recent water/lava source vents in the Cerberus plains: Stratigraphic andcrater count age constraints

    NASA Astrophysics Data System (ADS)

    Thomas, Rebecca J.

    2013-04-01

    In order to investigate sources of lava and water to the Cerberus plains of Mars, geomorphological mapping on High Resolution Imaging Science Experiment (HiRISE) images was carried out to reveal the history of activity of fissures and pits which lie upstream of channels and deposits associated with a wrinkle ridge near Cerberus Fossae. The fissures and pits are superbly exposed and imaged, and flows and channels emanate directly from them, interpreted as clear evidence that these are vents. The mapping establishes stratigraphic relationships between the plains and the channels and deposits originating from the vents, establishing the vent history. For example, to the south of the wrinkle ridge, both incised channels and leveed flows extend onto the southern plain and are clearly the final phase of plains-forming activity. Conversely, to the north, vent-sourced channels only incise the plain close to the ridge—beyond that, they are overlain by large-scale regional flows that appear to have originated from the direction of Athabasca Valles. In the southeast, there is evidence of contemporaneity between vent-sourced activity and large-scale plains-forming flow that was not sourced from the vents, indicating that activity here was part of a broader process of Cerberus plains formation from multiple sources. Crater counts show all the activity to be Late Amazonian, with the latest activity tentatively dating to circa 11 Ma. Thus, this study implies that very recent outflows from these vents contributed to the formation of the Cerberus plains and constrains the timing and local flow direction of plains-forming deposits from other sources.

  3. Video Observations by Telepresence Reveal Two Types of Hydrothermal Venting on Kawio Barat Seamount

    NASA Astrophysics Data System (ADS)

    Butterfield, D. A.; Holden, J. F.; Shank, T. M.; Tunnicliffe, V.; Sherrin, J.; Herrera, S.; Baker, E. T.; Lovalvo, D.; Makarim, S.; Malik, M. A.; Wirasantosa, S.; Hammond, S. R.

    2010-12-01

    The INDEX-SATAL 2010 expedition began an international exploration of the seafloor in Indonesian waters using the methodology of telepresence, conducting EM302 multibeam mapping, water column CTD, and ROV high-definition video operations and sending data back to Exploration Command Centers in Indonesia and Seattle. Science observers in other locations in the US and Canada were engaged in real-time observations and interpretation of results. One mission goal was to locate hydrothermal or volcanic activity. Intense light scattering and redox potential measurements in the water column over Kawio Barat (KB)indicated a high level of hydrothermal activity, and direct video observations confirmed venting near the summit. None of the other volcanic features west of the Sangihe arc that were investigated during the mission had confirmed hydrothermal activity. ROV capabilities did not include physical sampling or temperature measurement, so our interpretation is based on visual comparison to other known sites. The steep western flank of KB from 2000 m depth to the summit (1850 m) has many areas of white and orange staining on exposed rocks, with some elemental sulfur, and broad areas covered with dark volcaniclastic sand, but no active venting was seen. KB has a summit ridge running WNW-ESE, with a major cross-cutting ridge on the western portion of the summit. Hydrothermal activity is concentrated near the eastern side of this intersection, on both the northern and southern sides of the summit ridge. Venting on the northern side of the summit ridge is characterized by intense white particle-rich fluids emanating directly from the rocky substrate with frozen flows of elemental sulfur down slope. This type of venting is visually very similar to the venting seen on NW Rota-1, an actively erupting volcano in the Mariana arc, and suggests that KB is actively releasing magmatic gases rich in sulfur dioxide to produce the elemental sulfur flows, inferred fine particulate sulfur

  4. Effects of Vent Asymmetry on Steady and Unsteady Eruption Dynamics

    NASA Astrophysics Data System (ADS)

    Sim, S.; Ogden, D.

    2013-12-01

    Models of volcanic eruptions are typically based on symmetric vent and conduit geometries. However, in natural settings, these features are rarely perfectly symmetric. For example, the May 18, 1980 eruption of Mount St Helens (MSH) took place through a highly asymmetrical crater due to the preceding landslide and subsequent vent erosion. In supersonic, high-pressure eruptions, such as what may have occurred at MSH, vent and crater asymmetry can strongly affect the directionality of the eruption. Here we explore flow dynamics resulting from a supersonic, high-pressure eruption though an asymmetric volcanic vent and a symmetric vent using a both unsteady numerical simulations and semi-analytical steady-state models. Preliminary results from both methods suggest that asymmetric vent shape may provide a first-order effect on dynamics of the initial phases of explosive eruptions.

  5. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  6. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  7. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  8. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  9. 46 CFR 153.353 - High velocity vents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false High velocity vents. 153.353 Section 153.353 Shipping... Systems § 153.353 High velocity vents. The discharge point of a B/3 or 4m venting system must be located..., unimpeded jet; (b) The jet has a minimum exit velocity of 30 m/sec (approx. 98.4 ft/sec); and (c) The...

  10. Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge

    NASA Astrophysics Data System (ADS)

    Copley, J. T.; Marsh, L.; Glover, A. G.; Hühnerbach, V.; Nye, V. E.; Reid, W. D. K.; Sweeting, C. J.; Wigham, B. D.; Wiklund, H.

    2016-12-01

    The Southwest Indian Ridge is the longest section of very slow to ultraslow-spreading seafloor in the global mid-ocean ridge system, but the biogeography and ecology of its hydrothermal vent fauna are previously unknown. We collected 21 macro- and megafaunal taxa during the first Remotely Operated Vehicle dives to the Longqi vent field at 37° 47‧S 49° 39‧E, depth 2800 m. Six species are not yet known from other vents, while six other species are known from the Central Indian Ridge, and morphological and molecular analyses show that two further polychaete species are shared with vents beyond the Indian Ocean. Multivariate analysis of vent fauna across three oceans places Longqi in an Indian Ocean province of vent biogeography. Faunal zonation with increasing distance from vents is dominated by the gastropods Chrysomallon squamiferum and Gigantopelta aegis, mussel Bathymodiolus marisindicus, and Neolepas sp. stalked barnacle. Other taxa occur at lower abundance, in some cases contrasting with abundances at other vent fields, and δ13C and δ15N isotope values of species analysed from Longqi are similar to those of shared or related species elsewhere. This study provides baseline ecological observations prior to mineral exploration activities licensed at Longqi by the United Nations.

  11. Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge

    PubMed Central

    Copley, J. T.; Marsh, L.; Glover, A. G.; Hühnerbach, V.; Nye, V. E.; Reid, W. D. K.; Sweeting, C. J.; Wigham, B. D.; Wiklund, H.

    2016-01-01

    The Southwest Indian Ridge is the longest section of very slow to ultraslow-spreading seafloor in the global mid-ocean ridge system, but the biogeography and ecology of its hydrothermal vent fauna are previously unknown. We collected 21 macro- and megafaunal taxa during the first Remotely Operated Vehicle dives to the Longqi vent field at 37° 47′S 49° 39′E, depth 2800 m. Six species are not yet known from other vents, while six other species are known from the Central Indian Ridge, and morphological and molecular analyses show that two further polychaete species are shared with vents beyond the Indian Ocean. Multivariate analysis of vent fauna across three oceans places Longqi in an Indian Ocean province of vent biogeography. Faunal zonation with increasing distance from vents is dominated by the gastropods Chrysomallon squamiferum and Gigantopelta aegis, mussel Bathymodiolus marisindicus, and Neolepas sp. stalked barnacle. Other taxa occur at lower abundance, in some cases contrasting with abundances at other vent fields, and δ13C and δ15N isotope values of species analysed from Longqi are similar to those of shared or related species elsewhere. This study provides baseline ecological observations prior to mineral exploration activities licensed at Longqi by the United Nations. PMID:27966649

  12. Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge.

    PubMed

    Copley, J T; Marsh, L; Glover, A G; Hühnerbach, V; Nye, V E; Reid, W D K; Sweeting, C J; Wigham, B D; Wiklund, H

    2016-12-14

    The Southwest Indian Ridge is the longest section of very slow to ultraslow-spreading seafloor in the global mid-ocean ridge system, but the biogeography and ecology of its hydrothermal vent fauna are previously unknown. We collected 21 macro- and megafaunal taxa during the first Remotely Operated Vehicle dives to the Longqi vent field at 37° 47'S 49° 39'E, depth 2800 m. Six species are not yet known from other vents, while six other species are known from the Central Indian Ridge, and morphological and molecular analyses show that two further polychaete species are shared with vents beyond the Indian Ocean. Multivariate analysis of vent fauna across three oceans places Longqi in an Indian Ocean province of vent biogeography. Faunal zonation with increasing distance from vents is dominated by the gastropods Chrysomallon squamiferum and Gigantopelta aegis, mussel Bathymodiolus marisindicus, and Neolepas sp. stalked barnacle. Other taxa occur at lower abundance, in some cases contrasting with abundances at other vent fields, and δ(13)C and δ(15)N isotope values of species analysed from Longqi are similar to those of shared or related species elsewhere. This study provides baseline ecological observations prior to mineral exploration activities licensed at Longqi by the United Nations.

  13. High temperature hydrogen sulfide adsorption on activated carbon - I. Effects of gas composition and metal addition

    USGS Publications Warehouse

    Cal, M.P.; Strickler, B.W.; Lizzio, A.A.

    2000-01-01

    Various types of activated carbon sorbents were evaluated for their ability to remove H2S from a simulated coal gas stream at a temperature of 550 ??C. The ability of activated carbon to remove H2S at elevated temperature was examined as a function of carbon surface chemistry (oxidation, thermal desorption, and metal addition), and gas composition. A sorbent prepared by steam activation, HNO3 oxidation and impregnated with Zn, and tested in a gas stream containing 0.5% H2S, 50% CO2 and 49.5% N2, had the greatest H2S adsorption capacity. Addition of H2, CO, and H2O to the inlet gas stream reduced H2S breakthrough time and H2S adsorption capacity. A Zn impregnated activated carbon, when tested using a simulated coal gas containing 0.5% H2S, 49.5% N2, 13% H2, 8.5% H2O, 21% CO, and 7.5% CO2, had a breakthrough time of 75 min, which was less than 25 percent of the length of breakthrough for screening experiments performed with a simplified gas mixture of 0.5% H2S, 50% CO2, and 49.5% N2.

  14. Development of an Absolute Gas-Counting Capability for Low to Medium Activities

    SciTech Connect

    Williams, Richard M.; Aalseth, Craig E.; Ely, James H.; Day, Anthony R.; Hayes, James C.; Hoppe, Eric W.; LaFerriere, Brian D.; Mace, Emily K.; Merriman, Jason H.; Overman, Cory T.; Seifert, Allen

    2013-11-01

    ABSTRACT Pacific Northwest National Laboratory (PNNL) is developing a capability to measure the absolute activity concentration of various gaseous radionuclides using length-compensated proportional-counting methods. This capability will enable the validation and use of low-level, gaseous radionuclide calibration standards for use in PNNL’s shallow underground laboratory. Two sets of unequal length proportional counters have been fabricated. These detector assemblies operate on a static gas-fill principle, in contrast to continuous, flow-through configurations. One set of three counters has been fabricated using ultra-low background (ULB) electroformed copper and low-background fabrication methods. Once fully operational, these ULB counters will be used in PNNL’s shallow underground counting laboratory for analysis of gases with low activity concentrations < 1 Bq/cc. A second set of four unequal length counters has been fabricated from Oxygen-Free High-Conductivity Copper (OFHC) using similar low-background cleaning and assembly methods. These OFHC counters will be operated above ground in the analysis of gases with activity concentrations in the range of 1-10 Bq/cc. A gas delivery system is being developed to actively mix the analyte gas with an appropriate amount of count-gas and uniformly deliver it to the counters with high accuracy and repeatability. A description of both detector assemblies and gas delivery system will be given along with a preliminary uncertainty analysis of a simulated 0.05 Bq/cm3 gas measurement.

  15. A Reactive-Transport Model Describing Methanogen Growth and Methane Production in Diffuse Flow Vents at Axial Seamount

    NASA Astrophysics Data System (ADS)

    Algar, C. K.

    2015-12-01

    Hydrogenotrophic methanogenesis is an important mode of metabolism in deep-sea hydrothermal vents. Diffuse vent fluids often show a depletion in hydrogen with a corresponding increase in methane relative to pure-mixing of end member fluid and seawater, and genomic surveys show an enrichment in genetic sequences associated with known methanogens. However, because we cannot directly sample the subseafloor habitat where these organisms are living, constraining the size and activity of these populations remains a challenge and limits our ability to quantify the role they play in vent biogeochemistry. Reactive-transport modeling may provide a useful tool for approaching this problem. Here we present a reactive-transport model describing methane production along the flow-path of hydrothermal fluid from its high temperature end-member to diffuse venting at the seafloor. The model is set up to reflect conditions at several diffuse vents in the Axial Seamount. The model describes the growth of the two dominant thermophilic methanogens, Methanothermococcus and Methanocaldococcus, observed at Axial seamount. Monod and Arrhenius constants for Methanothermococcus thermolithotrophicus and Methanocaldococcus jannaschii were obtained for the model using chemostat and bottle experiments at varying temperatures. The model is used to investigate the influence of different mixing regimes on the subseafloor populations of these methanogens. By varying the model flow path length and subseafloor cell concentrations, and fitting to observed hydrogen and methane concentrations in the venting fluid, the subseafloor biomass, fluid residence time, and methane production rate can be constrained.

  16. 33. BUILDING 1006, TYPICAL CEILING VENT REGISTER. Presidio of ...

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

    33. BUILDING 1006, TYPICAL CEILING VENT REGISTER. - Presidio of San Francisco, Letterman General Hospital, Building No. 27, Letterman Hospital Complex, Edie Road, San Francisco, San Francisco County, CA

  17. Comparison of offshore and onshore gas occurrences, Eel River basin, northern California

    USGS Publications Warehouse

    Lorenson, T.D.; McLaughlin, Robert J.; Kvenvolden, Keith A.; Orange, Daniel L.; Davisson, M. Lee; Brewer, Peter G.; Martin, J.B.

    1998-01-01

    The Eel River basin of northern California is a upper Cenozoic depocenter containing more than 3,000 meters of sedimentary rock located near the Mendocino triple junction. Active tectonism has resulted in folding, faulting and rapid sedimentation. Both thermogenic and microbial hydrocarbons are known to be present in the sediments. In August 1997, we sampled two submarine gas seeps, one at a water depth of 520 m that supports a chemosynthetic-based ecosystem very near an area of previously recovered gas hydrate. Another vent site was sampled in sand covered with white bacterial mats at a water depth 41 m. We compared the hydrocarbon gas composition and methane isotopic composition of these seeps with land-based gas occurrences that include: 1) a gas seep and 2) gas from a 2360 m-deep gas well.

  18. Plumes and Jets: Constraints on Vents and Eruption Dynamics from Observations and Models

    NASA Astrophysics Data System (ADS)

    Schmidt, J.

    2014-12-01

    Plume activity of Enceladus has been monitored by Cassini for nearly one decade after their discovery (see Science, 2006, 311, special issue). Thus, crucial properties of the vapor dust plumes are constrained in a fairly detailed manner. In this paper I discuss implications for vent geometries, gas and grain dynamics and condensation in the vents. Vapor source rates on the order of 100 to 1000kg/s were derived from remote and in-situ data [2, 3, 4, 1, 17] and distortions in the B field [10, 15]). Gas ejection speeds from 500m/s to 1000m/s [18, 4] (escape speed 240m/s) indicate supersonic gas flow. Evidence for supersonic gas jets is directly seen in UVIS data [3]. Dust production rates between 5 to 50kg/s have been inferred [16, 8]. These do not yet include mass in jets of very fine nano-grains [9, 8, 7]. The dust plume exhibits scale heights that suggest ejection speeds on the order of 100m/s [13, 16, 6], i.e. well below the escape velocity. Larger grains have smaller ejection spees populating the lower parts of the plume [6, 16]. Salt has been identified in grains on the percent level [14] so that they cannot form alone by condensation from vapor. The detailed distribution of dust sources and jet orientations on the south polar terrain was derived from images and compared to temperature distributions and to the expected tidal stress pattern from modelling [12]. A recent observations show that plume brightness varies roughly by a factor of three with the orbital period of Enceladus, suggesting that ejection strength is tidally controlled [11, 5]. A similar variation in the gas discharge is expected but has not yet been observed to date. Remarkably, there is no such correlation of orbital phase and the observed scale height of dust jets. [1] Dong et al, JGR, 116, 2011[2] Hansen et al, Science, 311, 2006. [3] Hansen et al, Nature, 456, 2008.[4] Hansen et al, GRL, 38, 2011.[5] Hedman et al, Nature, 2013.[6] Hedman et al, ApJ, 693, 2009.[7] Hill et al, JGR, 117, 2012

  19. The sound field near hydrothermal vents on Axial Seamount, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Little, Sarah A.; Stolzenbach, Keith D.; Purdy, G. Michael

    1990-08-01

    High-quality acoustic noise measurements were obtained by two hydrophones located 3 m and 40 m from an active hydrothermal vent on Axial Seamount, Juan de Fuca Ridge, in an effort to determine the feasibility of monitoring hydrothermal vent activity through flow noise generation. Most of the measured noise field could be attributed to ambient ocean noise sources of microseisms, distant shipping, and weather, punctuated by local ships and biological sources. Long-period, low-velocity, water/rock interface waves were detected with high amplitudes which rapidly decayed with distance from the seafloor. Detection of vent signals was hampered by unexpected spatial nonstationarity due to the shadowing effects of the caldera wall. No continuous vent signals were deemed significant based on a criterion of 90% probability of detection and 5% probability of false alarm. However, a small signal near 40 Hz, with a power level of 10-4Pa2/Hz was noticed on two records taken within 3 m of the Inferno black smoker. Hie frequency of this signal is consistent with predictions, and the power level suggests the occurrence of jet noise amplification due to convected density inhomogeneities.

  20. Sound field near hydrothermal vents on Axial Seamount, Juan de Fuca Ridge. Technical report

    SciTech Connect

    Little, S.A.; Stolzenbach, K.D.; Purdy, G.M.

    1990-08-10

    High-quality acoustic noise measurements were obtained by two hydrophones located 3 m and 40 m from an active hydrothermal vent on Axial Seamount, Juan de Fuca Ridge, in an effort to determine the feasibility of monitoring hydrothermal vent activity through flow noise generation. Most of the measured noise field could be attributed to ambient ocean noise sources of microseisms, distant shipping, and weather, punctuated by local ships and biological sources. Long-period, low-velocity, water/rock interface waves were detected with high amplitudes which rapidly decayed with distance from the seafloor. Detection of vent signals was hampered by unexpected spatial nonstationarity due to the shadowing effects of the calders wall. No continuous vent signals were deemed significant based on a criterion of 90% probability of detection and 5% probability of false alarm. However, a small signal near 40 Hz, with a power level of 0.0001 Pa sq/Hz was noticed on two records taken within 3 m of the Inferno black smoker. The frequency of this signal is consistent with predictions, and the power level suggests the occurrence of jet noise amplification due to convected density inhomogeneities. Keywords: Seamounts; Flow noise; Underwater acoustics; Acoustic measurement; Geothermy/noise; Ocean ridges; Underwater sound signals; Reprints; North Pacific Ocean. (EDC).

  1. Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean.

    PubMed

    Lee, Seyong; Kim, Se-Joo; Ju, Se-Jong; Pak, Sang-Joon; Son, Seung-Kyu; Yang, Jisook; Han, Seunghee

    2015-05-01

    We provide the mercury (Hg) and monomethylmercury (MMHg) levels of the plume water, sulfide ore, sediment, and mollusks located at the hydrothermal vent fields of the southern Tonga Arc, where active volcanism and intense seismic activity occur frequently. Our objectives were: (1) to address the potential release of Hg from hydrothermal fluids and (2) to examine the distribution of Hg and MMHg levels in hydrothermal mollusks (mussels and snails) harboring chemotrophic bacteria. While high concentrations of Hg in the sediment and Hg, As, and Sb in the sulfide ore indicates that their source is likely hydrothermal fluids, the MMHg concentration in the sediment was orders of magnitude lower than the Hg (<0.001%). It suggests that Hg methylation may have not been favorable in the vent field sediment. In addition, Hg concentrations in the mollusks were much higher (10-100 times) than in other hydrothermal vent environments, indicating that organisms located at the Tonga Arc are exposed to exceedingly high Hg levels. While Hg concentration was higher in the gills and digestive glands than in the mantles and residues of snails and mussels, the MMHg concentrations in the gills and digestive glands were orders of magnitude lower (0.004-0.04%) than Hg concentrations. In summary, our results suggest that the release of Hg from the hydrothermal vent fields of the Tonga Arc and subsequent bioaccumulation are substantial, but not for MMHg.

  2. Application of SAFIRE in the design of an emergency relief vent for a storage vessel

    SciTech Connect

    Shaw, D.A.; Levin, M.E.

    1995-12-31

    For a gas-producing (gassy) decomposition reaction with established kinetics, SAFIRE (Systems Analysis For Integrated Relief Evaluation) is applied to design pressure relief vents for two storage vessels. The reactant concentration in the solvent differs significantly between the two vessels. SAFIRE is employed to validate experimentally derived kinetics through simulation of the reaction`s concentration, temperature and pressure history in the testing apparatus. Following this, SAFIRE is then applied to determine safe vent sizes for commercial-scale vessels. For the particular system under study, {open_quotes}hybrid/tempered{close_quotes} or {open_quotes}hybrid/nontempered{close_quotes} behavior may be observed, depending on the reactant concentration. The results for these two systems are compared. The utility and flexibility of SAFIRE are also demonstrated. 17 refs., 23 figs., 2 tabs.

  3. Geodatabase of Wyoming statewide oil and gas drilling activity to 2010

    USGS Publications Warehouse

    Biewick, Laura R.H.

    2011-01-01

    The U.S. Geological Survey (USGS) compiled a geographic information system (GIS) of Wyoming statewide historical oil and gas drilling activity for the Wyoming Landscape Conservation Initiative (WLCI). The WLCI is representative of the partnerships being formed by the USGS with other Department of the Interior bureaus, State and local agencies, industry, academia, and private landowners that are committed to maintaining healthy landscapes, sustaining wildlife, and preserving recreational and grazing uses as energy resources development progresses in southwestern Wyoming. This product complements the 2009 USGS publication on oil and gas development in southwestern Wyoming http://pubs.usgs.gov/ds/437/) by approximating, based on database attributes, the time frame of drilling activity for each well (start and stop dates). This GIS product also adds current oil and gas drilling activity not only in the area encompassing the WLCI, but also statewide. Oil and gas data, documentation, and spatial data processing capabilities are available and can be downloaded from the USGS website. These data originated from the Wyoming Oil and Gas Conservation Commission (WOGCC), represent decades of oil and gas drilling (1900 to 2010), and will facilitate a landscape-level approach to integrated science-based assessments, resource management and land-use decision making.

  4. Phylogenetic Diversity of Nitrogenase (nifH) Genes in Deep-Sea and Hydrothermal Vent Environments of the Juan de Fuca Ridge

    PubMed Central

    Mehta, Mausmi P.; Butterfield, David A.; Baross, John A.

    2003-01-01

    The subseafloor microbial habitat associated with typical unsedimented mid-ocean-ridge hydrothermal vent ecosystems may be limited by the availability of fixed nitrogen, inferred by the low ammonium and nitrate concentrations measured in diffuse hydrothermal fluid. Dissolved N2 gas, the largest reservoir of nitrogen in the ocean, is abundant in deep-sea and hydrothermal vent fluid. In order to test the hypothesis that biological nitrogen fixation plays an important role in nitrogen cycling in the subseafloor associated with unsedimented hydrothermal vents, degenerate PCR primers were designed to amplify the nitrogenase iron protein gene nifH from hydrothermal vent fluid. A total of 120 nifH sequences were obtained from four samples: a nitrogen-poor diffuse vent named marker 33 on Axial Volcano, sampled twice over a period of 1 year as its temperature decreased; a nitrogen-rich diffuse vent near Puffer on Endeavour Segment; and deep seawater with no detectable hydrothermal plume signal. Subseafloor nifH genes from marker 33 and Puffer are related to anaerobic clostridia and sulfate reducers. Other nifH genes unique to the vent samples include proteobacteria and divergent Archaea. All of the nifH genes from the deep-seawater sample are most closely related to the thermophilic, anaerobic archaeon Methanococcus thermolithotrophicus (77 to 83% amino acid similarity). These results provide the first genetic evidence of potential nitrogen fixers in hydrothermal vent environments and indicate that at least two sources contribute to the diverse assemblage of nifH genes detected in hydrothermal vent fluid: nifH genes from an anaerobic, hot subseafloor and nifH genes from cold, oxygenated deep seawater. PMID:12571018

  5. FLAME facility: The effect of obstacles and transverse venting on flame acceleration and transition on detonation for hydrogen-air mixtures at large scale

    SciTech Connect

    Sherman, M.P.; Tieszen, S.R.; Benedick, W.B.

    1989-04-01

    This report describes research on flame acceleration and deflagration-to-detonation transition (DDT) for hydrogen-air mixtures carried out in the FLAME facility, and describes its relevance to nuclear reactor safety. Flame acceleration and DDT can generate high peak pressures that may cause failure of containment. FLAME is a large rectangular channel 30.5 m long, 2.44 m high, and 1.83 m wide. It is closed on the ignition end and open on the far end. The three test variables were hydrogen mole fraction (12--30%), degree of transverse venting (by moving steel top plates---0%, 13%, and 50%), and the absence or presence of certain obstacles in the channel (zero or 33% blockage ratio). The most important variable was the hydrogen mole fraction. The presence of the obstacles tested greatly increased the flame speeds, overpressures, and tendency for DDT compared to similar tests without obstacles. Different obstacle configurations could have greater or lesser effects on flame acceleration and DDT. Large degrees of transverse venting reduced the flame speeds, overpressures, and possibility of DDT. For small degrees of transverse venting (13% top venting), the flame speeds and overpressures were higher than for no transverse venting with reactive mixtures (>18% H/sub 2/), but they were lower with leaner mixtures. The effect of the turbulence generated by the flow out the vents on increasing flame speed can be larger than the effect of venting gas out of the channel and hence reducing the overpressure. With no obstacles and 50% top venting, the flame speeds and overpressures were low, and there was no DDT. For all other cases, DDT was observed above some threshold hydrogen concentration. DDT was obtained at 15% H/sub 2/ with obstacles and no transverse venting. 67 refs., 62 figs.

  6. Activated carbon from vetiver roots: gas and liquid adsorption studies.

    PubMed

    Gaspard, S; Altenor, S; Dawson, E A; Barnes, P A; Ouensanga, A

    2007-06-01

    Large quantities of lignocellulosic residues result from the industrial production of essential oil from vetiver grass (Vetiveria zizanioides) roots. These residues could be used for the production of activated carbon. The yield of char obtained after vetiver roots pyrolysis follows an equation recently developed [A. Ouensanga, L. Largitte, M.A. Arsene, The dependence of char yield on the amounts of components in precursors for pyrolysed tropical fruit stones and seeds, Micropor. Mesopor. Mater. 59 (2003) 85-91]. The N(2) adsorption isotherm follows either the Freundlich law K(F)P(alpha) which is the small alpha equation limit of a Weibull shaped isotherm or the classical BET isotherm. The surface area of the activated carbons are determined using the BET method. The K(F) value is proportional to the BET surface area. The alpha value increases slightly when the burn-off increases and also when there is a clear increase in the micropore distribution width.

  7. Activated carbon treatment of municipal solid waste incineration flue gas.

    PubMed

    Lu, Shengyong; Ji, Ya; Buekens, Alfons; Ma, Zengyi; Jin, Yuqi; Li, Xiaodong; Yan, Jianhua

    2013-02-01

    Activated carbon injection is widely used to control dioxins and mercury emissions. Surprisingly little attention has been paid to its modelling. This paper proposes an expansion of the classical Everaerts-Baeyens model, introducing the expression of fraction of free adsorption sites, f (s), and asserting the significant contribution of fly ash to dioxins removal. Moreover, the model monitors dioxins partitioning between vapour and particulate phase, as well as removal efficiency for each congener separately. The effects of the principal parameters affecting adsorption are analysed according to a semi-analytical, semi-empirical model. These parameters include temperature, contact time during entrained-flow, characteristics (grain-size, pore structure, specific surface area) and dosage of activated carbon, lignite cokes or mineral adsorbent, fly ash characteristics and concentration, and type of incinerator plant.

  8. Diffuse flow from hydrothermal vents. Doctoral thesis

    SciTech Connect

    Trivett, D.A.

    1991-08-01

    The effluent from a collection of diffuse hydrothermal vents was modelled to determine the fate of the source of flow under typical environmental conditions at seafloor spreading centers. A laboratory simulation was conducted to test an analytic model of diffuse plume rise. The results showed that diffuse plumes are likely to remain near the seafloor, with their maximum rise height scaled with the diameter of the source of diffuse flow. The entrainment of ambient seawater into these plumes is limited by the proximity to the seafloor, thus slowing the rate of dilution. The model of diffuse plume behaviour was used to guide the design and implementation of a scheme for monitoring the flow from diffuse hydrothermal vents in the ocean. A deployment of an array at the Southern Juan de Fuca Ridge yielded measurements of a variety of diffuse plume properties, including total heat output. Two distinct sources of hydrothermal flow were detected during the field deployment. The larger source was 1-1.5km north of the instrument array, and its energy output was 450 + or - 270MW. A smaller source was located 100m east of one instrument in the array. The energy output of the source was 12 + or - 8MW. The rise heights of the centerlines of these plumes were 45m and 10m, respectively.

  9. MAVEN Contamination Venting and Outgassing Analysis

    NASA Technical Reports Server (NTRS)

    Petro, Elaine M.; Hughes, David W.; Secunda, Mark S.; Chen, Philip T.; Morrissey, James R.; Riegle, Catherine A.

    2014-01-01

    Mars Atmosphere and Volatile EvolutioN (MAVEN) is the first mission to focus its study on the Mars upper atmosphere. MAVEN will study the evolution of the Mars atmosphere and climate, by examining the conduit through which the atmosphere has to pass as it is lost to the upper atmosphere. An analysis was performed for the MAVEN mission to address two distinct concerns. The first goal of the analysis was to perform an outgassing study to determine where species outgassed from spacecraft materials would redistribute to and how much of the released material might accumulate on sensitive surfaces. The second portion of the analysis serves to predict what effect, if any, Mars atmospheric gases trapped within the spacecraft could have on instrument measurements when re-released through vents. The re-release of atmospheric gases is of interest to this mission because vented gases from a higher pressure spacecraft interior could bias instrument measurements of the Mars atmosphere depending on the flow rates and directions.

  10. 40 CFR Table 3 to Subpart Vvvvvv... - Emission Limits and Compliance Requirements for Continuous Process Vents

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... closed-vent system to a flare (except that a flare may not be used to control halogenated vent streams... therein i. As specified in § 63.11496(e). 2. Halogenated vent stream that is controlled through...

  11. The application of masonry chimney venting tables for oil-fired appliances

    SciTech Connect

    Krajewski, R.F.; Strasser, J.

    1995-04-01

    This paper presents an overview of the results of work in developing a set of rational guidelines for the venting of modern oil-fired appliances. The activities included the continued development and completion of the Oil-Heat Vent Analysis Program (OHVAP), Version 1.0 and the interpretation of nearly 2,000 runs in preparing recommendations for presentation in table form. These results are presented in the form of venting tables for the installation of chimney vent systems for mid- and high-efficiency oil-fired heating appliances using masonry chimneys. A brief description of OHVAP is given as well as a discussion of what the program does. Recommendations based on the results of OHVAP are presented in the form of five tables spanning oil-fired appliance Steady state Efficiencies (Eff{sub ss}) of 80% to 88%. The assumptions used in the calculations and examples of the computed results are presented as well as a discussion of the rationale for masonry chimney system treatment. Working examples are given with suggested diagnostic approaches for application of the table recommendations.

  12. Dynamic character of the hydrothermal vent habitat and the nature of sulphide chimney fauna

    NASA Astrophysics Data System (ADS)

    Tunnicliffe, Verena; Kim Juniper, S.

    A major substratum for vent organisms on Juan de Fuca and Explorer Ridges of the northeast Pacific is the polymetallic sulphide chimney. The deposition processes and subsequent growth of such chimneys provide a dynamic and extreme habitat that changes rapidly. During initial venting stages, colonization must await stabilization of the chimney structure. As the porous anhydrite shell accumulates sulphide minerals, protection from direct hot water contact increases for organisms colonizing the outer walls while sufficient vent water still diffuses for the support of chemosynthesis. Vestimentiferan worms are found on small sulphide mounds but the active growth and collapse of anhydrite spires is a major source of disruption and mortality. High temperature venting and spire growth appear to attract alvinellid polychaetes which may be implicated in the process of strengthening and sealing the anhydrite spires. Fauna on the growing chimney is subject to changes in fluid flow patterns that can make the structure uninhabitable. Large chimneys are inhabited by more species indicating that a diversification of habitat results from variations in mineralization and fluid availability. Chimney fauna has become specialized in exploiting an unpredictable and unstable habitat in an extreme example of the control of biotic development by the physical environment.

  13. 78 FR 33051 - Notification of Proposed Production Activity, The Gas Company, LLC dba Hawai'i Gas, Subzone 9F...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-03

    ... currently has authority to produce synthetic natural gas, carbon dioxide, hydrogen, hydrocarbon gas mixtures... natural gas, carbon dioxide, hydrogen, hydrocarbon gas mixtures and zinc sulfide (duty rate ranges from... abroad include: mixtures of light petroleum derivative hydrocarbons, including medium to light...

  14. Hydrogen Gas Emissions from Active Faults and Identification of Flow Pathway in a Fault Zone

    NASA Astrophysics Data System (ADS)

    Ishimaru, T.; Niwa, M.; Kurosawa, H.; Shimada, K.

    2010-12-01

    It has been observed that hydrogen gas emissions from the subsurface along active faults exceed atmospheric concentrations (e.g. Sugisaki et. al., 1983). Experimental studies have shown that hydrogen gas is generated in a radical reaction of water with fractured silicate minerals due to rock fracturing caused by fault movement (e.g. Kita et al., 1982). Based on such research, we are studying an investigation method for an assessment of fault activity using hydrogen gas emissions from fracture zones. To start, we have devised portable equipment for rapid and simple in situ measurement of hydrogen gas emissions (Shimada et al., 2008). The key component of this equipment is a commercially available and compact hydrogen gas sensor with an integral data logger operable at atmospheric pressure. In the field, we have drilled shallow boreholes into incohesive fault rocks to depths ranging from 15 to 45 cm using a hand-operated drill with a 9mm drill-bit. Then, we have measured the hydrogen gas concentrations in emissions from active faults such as: the western part of the Atotsugawa fault zone, the Atera fault zone and the Neodani fault in central Japan; the Yamasaki fault zone in southwest Japan; and the Yamagata fault zone in northeast Japan. In addition, we have investigated the hydrogen gas concentrations in emissions from other major geological features such as tectonic lines: the Butsuzo Tectonic Line in the eastern Kii Peninsula and the Atokura Nappe in the Northeastern Kanto Mountains. As a result of the investigations, hydrogen gas concentration in emissions from the active faults was measured to be in the approximate range from 6,000 ppm to 26,000 ppm in two to three hours after drilling. A tendency for high concentrations of hydrogen gas in active faults was recognized, in contrast with low concentrations in emissions from tectonic lines that were observed to be in the range from 730 ppm to 2,000 ppm. It is inferred that the hydrogen gas migrates to ground

  15. Isotopic Approaches to Allying Productivity and Sulfur Metabolism in Three Symbiotic Hydrothermal Vent Molluscs

    NASA Astrophysics Data System (ADS)

    Beinart, R.; Gartman, A.; Sanders, J. G.; Luther, G. W.; Girguis, P. R.

    2012-12-01

    Symbioses between animals and chemosynthetic bacteria predominate at hydrothermal vents. In these associations, the endosymbiotic bacteria utilize chemical reductants for the energy to support autotrophy, providing primary nutrition for the host. Despite their ubiquity at vents worldwide, little is known about the rates of productivity of these symbioses under different physico-chemical regimes or how their metabolism effects the local geochemical environment. To address this matter, we used high-pressure flow through incubations and stable isotopic tracers to maintain three genera of symbiotic mollusc - the gastropods Alviniconcha and Ifremeria, and the mussel Bathymodiolus - at vent-like conditions. Via the incorporation of isotopically labeled compounds, we assessed their productivity when using different reduced sulfur species as reductants. Using cyclic voltammetry, mass spectrometry and discrete geochemical analyses, we concurrently measured their effect on sulfur flux from the vessels. We found that the symbionts of all three genera can support autotrophy with hydrogen sulfide and thiosulfate, though at different rates. Additionally, by examining the rate of isotopic incorporation into biomass, we revealed intra-generic variability in productivity among the individuals in our experimental assemblages that are likely related to differences in the geochemical regime along the length of reactor. These geochemical gradients are due to the activity of other individuals within the vessel, since those organisms closest to the influent of the vent-like water had the highest measured carbon incorporation. Finally, we measured the uptake and excretion of sulfur species, which illustrate the degree to which these symbioses might impact local sulfur chemistry in situ. These experiments show that A) access to particular sulfur species differentially affects the productivity of vent symbioses, suggesting that competition for these substrates, both within and between host

  16. Arsenic concentrations and species in three hydrothermal vent worms, Ridgeia piscesae, Paralvinella sulficola and Paralvinella palmiformis

    NASA Astrophysics Data System (ADS)

    Maher, W. A.; Duncan, E.; Dilly, G.; Foster, S.; Krikowa, F.; Lombi, E.; Scheckel, K.; Girguis, P.

    2016-10-01

    Hydrothermal vents are surficial expressions of subsurface geological and hydrological processes. Fluids emitting from active vents are chemically distinct from bottom seawater, and are enriched in dissolved metals and metalloids, including arsenic. Vent organisms accumulate arsenic but the arsenic speciation in these non-photosynthetic organisms is largely unknown. Here, arsenic concentrations and chemical species were measured in three deep sea hydrothermal vent worms (Ridgeia piscesae, Paralvinella sulfincola and Paralvinella palmiformis) from the Juan de Fuca Ridge in the Northwest pacific. R. piscesae has similar arsenic concentrations (3.8-35 μg g-1) to shallow water polychaetes while P. sulfincola and P. palmiformis have significantly higher arsenic concentrations (420-1417 and 125-321 μg g-1 respectively). R. piscesae contains appreciable quantities of inorganic arsenic (36±14%), monomethyl arsenic (2±2%), dimethyl arsenic (34±21%), an unknown methyl arsenical (7±16%), OSO3-arsenosugar (5±9%), TETRA (4±5%), ThioPO4/ThioDMAE (1±2%) and an unknown thio-arsenical (12±14%). These results suggests that host and symbionts are either involved in the methylation of arsenic, or are bathed in fluids enriched in methylated arsenic as a result of free-living microbial activity. The host carrying out methylation, however, cannot be ruled out. In contrast, 96-97% of the arsenic in P. sulfincola and P. palmiformis is inorganic arsenic, likely the result of arsenic precipitation within and upon the mucus they ingest while feeding. While all worms have oxo- and thio arsenosugars (2-30%), Paralvinella also have small amounts of arsenobetaine (<0.001-0.21%). The presence of arsenosugars, arsenobetaine and other minor arsenic species in the absence of photosynthesising algae/bacteria indicates that they may be formed by vent animals in the absence of sunlight, but at this time their formation cannot be explained.

  17. Microbial colonization of post eruptive vents on the EPR at 9N

    NASA Astrophysics Data System (ADS)

    Vetriani, C.

    2008-12-01

    The overarching goal of this project is to understand the role of microbial colonists at newly formed vents as "mediators" in the transfer of energy from the geothermal source to the higher trophic levels, and their role in altering fluid chemistry and in "conditioning" the vent environment for metazoans to settle. Following the 2005-06 volcanic eruption along the East Pacific Rise (EPR) ridge crest between 9°N and 9°N, we had several opportunities to investigate the microbial colonization of the post-eruptive vents: in 2006 (about six months after the eruption), in January 2007 (one year after the eruption), and in December 2007/January 2008 (two years after the eruption). In order to investigate microbial colonization, we designed and deployed several experimental microbial colonizers on active diffuse flow vents characterized by different temperatures (approximate range 20-60°C) chemical (different redox conditions), and biological (e.g., presence or absence of metazoan colonists) regimes. Analyses of the 16S rRNA and fuctional gene transcripts from the colonizing communities indicated that Epsilonproteobacteria represented the dominant and active fraction of the chemosynthetic early microbial colonists, and that they expressed in-situ the genes involved in carbon dioxide fixation and nitrate respiration. However, data from our semi quantitative culture experiments indicated that Epsilonproteobacteria were not the only microorganisms that attached to basalts or to the experimental colonizers during the early phases of colonization. Sulfur dependent, chemosynthetic members of the Gamma- and Alphaproteobacteria were isolated from up to 10-5 dilutions of original samples along with heterotrophic Gammaproteobacteria capable of growth on n-alkanes as their sole carbon source. We propose a model that links the chemistry of hydrothermal fluids to the colonization of newly formed vents and suggests a role for chemosynthetic and heterotrophic bacteria in the

  18. Production of activated char from Illinois coal for flue gas cleanup

    USGS Publications Warehouse

    Lizzio, A.A.; DeBarr, J.A.; Kruse, C.W.

    1997-01-01

    Activated chars were produced from Illinois coal and tested in several flue gas cleanup applications. High-activity chars that showed excellent potential for both SO2 and NOx removal were prepared from an Illinois No. 2 bituminous coal. The SO2 (120 ??C) and NOx (25 ??C) removal performance of one char compared favorably with that of a commercial activated carbon (Calgon Centaur). The NOx removal performance of the same char at 120 ??C exceeded that of the Centaur carbon by more than 1 order of magnitude. Novel char preparation methods were developed including oxidation/thermal desorption and hydrogen treatments, which increased and preserved, respectively, the active sites for SO2 and NOx adsorption. The results of combined SO2/NOx removal tests, however, suggest that SO2 and NOx compete for similar adsorption sites and SO2 seems to be more strongly adsorbed than NO. A low-activity, low-cost char was also developed for cleanup of incinerator flue gas. A three-step method involving coal preoxidation, pyrolysis, and CO2 activation was used to produce the char from Illinois coal. Five hundred pounds of the char was tested on a slipstream of flue gas from a commercial incinerator in Germany. The char was effective in removing >97% of the dioxins and furans present in the flue gas; mercury levels were below detectable limits.

  19. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit... ventilating effect of a pipe 4 inches (102 millimeters) in diameter; (2) The ventilation must be enough...

  20. 49 CFR 192.187 - Vaults: Sealing, venting, and ventilation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Vaults: Sealing, venting, and ventilation. 192.187... Components § 192.187 Vaults: Sealing, venting, and ventilation. Each underground vault or closed top pit... ventilating effect of a pipe 4 inches (102 millimeters) in diameter; (2) The ventilation must be enough...

  1. 40 CFR 63.983 - Closed vent systems.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Closed vent systems. 63.983 Section 63.983 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Closed Vent Systems, Control Devices, Recovery Devices and Routing to a Fuel...

  2. 40 CFR 63.983 - Closed vent systems.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Closed vent systems. 63.983 Section 63.983 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Closed Vent Systems, Control Devices, Recovery Devices and Routing to a Fuel...

  3. Zero-G thermodynamic vent system for shuttle/Centaur

    NASA Technical Reports Server (NTRS)

    Niggemann, Richard E.

    1987-01-01

    Viewgraphs are presented showing drawings of Centaur configurations, the Thermodynamic Vent System (TVS), the mixer pump, and the hydrogen vent motor pump inverter. A cryogenic performance summary is given in chart form. The TVS liquid flow operation and vapor flow operation are diagrammed.

  4. Deep-sea primary production at the Galapagos hydrothermal vents

    SciTech Connect

    Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.

    1980-03-21

    Dense animal populations surrounding recently discovered hydrothermal vents at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

  5. Antarctic marine biodiversity and deep-sea hydrothermal vents.

    PubMed

    Chown, Steven L

    2012-01-01

    The diversity of many marine benthic groups is unlike that of most other taxa. Rather than declining from the tropics to the poles, much of the benthos shows high diversity in the Southern Ocean. Moreover, many species are unique to the Antarctic region. Recent work has shown that this is also true of the communities of Antarctic deep-sea hydrothermal vents. Vent ecosystems have been documented from many sites across the globe, associated with the thermally and chemically variable habitats found around these, typically high temperature, streams that are rich in reduced compounds and polymetallic sulphides. The animal communities of the East Scotia Ridge vent ecosystems are very different to those elsewhere, though the microbiota, which form the basis of vent food webs, show less differentiation. Much of the biological significance of deep-sea hydrothermal vents lies in their biodiversity, the diverse biochemistry of their bacteria, the remarkable symbioses among many of the marine animals and these bacteria, and the prospects that investigations of these systems hold for understanding the conditions that may have led to the first appearance of life. The discovery of diverse and unusual Antarctic hydrothermal vent ecosystems provides opportunities for new understanding in these fields. Moreover, the Antarctic vents south of 60°S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty. Other deep-sea hydrothermal vents located in international waters are not protected and may be threatened by growing interests in deep-sea mining.

  6. 46 CFR 119.450 - Vent pipes for fuel tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Vent pipes for fuel tanks. 119.450 Section 119.450... Specific Machinery Requirements § 119.450 Vent pipes for fuel tanks. (a) Each unpressurized fuel tank must be fitted with a pipe connected to the highest point of the tank. (b) The minimum net cross...

  7. 46 CFR 119.450 - Vent pipes for fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Vent pipes for fuel tanks. 119.450 Section 119.450... Specific Machinery Requirements § 119.450 Vent pipes for fuel tanks. (a) Each unpressurized fuel tank must be fitted with a pipe connected to the highest point of the tank. (b) The minimum net cross...

  8. Hydrogen Vent Ground Umbilical Quick Disconnect - Flight Seal Advanced Development

    NASA Technical Reports Server (NTRS)

    Girard, Doug; Jankowski, Fred; Minich, Mark C.; Yu, Weiping

    2012-01-01

    This project is a team effort between NASA Engineering (NE) and Team QNA Engineering personnel to provide support for the Umbilical Systems Development project which is funded by Advanced Exploration Systems (AES) and 21st Century Launch Complex. Specifically, this project seeks to develop a new interface between the PPBE baselined Legacy SSP LH2 Vent Arm QD probe and SLS vent seal.

  9. 40 CFR 63.643 - Miscellaneous process vent provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Miscellaneous process vent provisions. (a) The owner or operator of a Group 1 miscellaneous process vent as defined in § 63.641 shall comply with the requirements of either paragraphs (a)(1) or (a)(2) of this section. (1) Reduce emissions of organic HAP's using a flare that meets the requirements of § 63.11(b)...

  10. Thermodynamic Vent System Test in a Low Earth Orbit Simulation

    NASA Technical Reports Server (NTRS)

    VanOverbeke, Thomas J.

    2004-01-01

    A thermodynamic vent system for a cryogenic nitrogen tank was tested in a vacuum chamber simulating oxygen storage in low earth orbit. The nitrogen tank was surrounded by a cryo-shroud at -40 F. The tank was insulated with two layers of multi-layer insulation. Heat transfer into cryogenic tanks causes phase change and increases tank pressure which must be controlled. A thermodynamic vent system was used to control pressure as the location of vapor is unknown in low gravity and direct venting would be wasteful. The thermodynamic vent system consists of a Joule-Thomson valve and heat exchanger installed on the inlet side of the tank mixer-pump. The combination is used to extract thermal energy from the tank fluid, reducing temperature and ullage pressure. The system was sized so that the tank mixer-pump operated a small fraction of the time to limit motor heating. Initially the mixer used sub-cooled liquid to cool the liquid-vapor interface inducing condensation and pressure reduction. Later, the thermodynamic vent system was used. Pressure cycles were performed until steady-state operation was demonstrated. Three test runs were conducted at tank fills of 97, 80, and 63 percent. Each test was begun with a boil-off test to determine heat transfer into the tank. The lower tank fills had time averaged vent rates very close to steady-state boil-off rates showing the thermodynamic vent system was nearly as efficient as direct venting in normal gravity.

  11. 46 CFR 38.20-1 - Venting-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Venting-T/ALL. 38.20-1 Section 38.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-1 Venting—T/ALL. (a) Each safety relief valve installed on a cargo tank shall be connected to...

  12. 46 CFR 38.20-5 - Venting-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Venting-T/ALL. 38.20-5 Section 38.20-5 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Venting and Ventilation § 38.20-5 Venting—T/ALL. (a) Safety relief valves on cargo tanks in barges may be connected...

  13. Nonlinear-Based MEMS Sensors and Active Switches for Gas Detection

    PubMed Central

    Bouchaala, Adam; Jaber, Nizar; Yassine, Omar; Shekhah, Osama; Chernikova, Valeriya; Eddaoudi, Mohamed; Younis, Mohammad I.

    2016-01-01

    The objective of this paper is to demonstrate the integration of a MOF thin film on electrostatically actuated microstructures to realize a switch triggered by gas and a sensing algorithm based on amplitude tracking. The devices are based on the nonlinear response of micromachined clamped-clamped beams. The microbeams are coated with a metal-organic framework (MOF), namely HKUST-1, to achieve high sensitivity. The softening and hardening nonlinear behaviors of the microbeams are exploited to demonstrate the ideas. For gas sensing, an amplitude-based tracking algorithm is developed to quantify the captured quantity of gas. Then, a MEMS switch triggered by gas using the nonlinear response of the microbeam is demonstrated. Noise analysis is conducted, which shows that the switch has high stability against thermal noise. The proposed switch is promising for delivering binary sensing information, and also can be used directly to activate useful functionalities, such as alarming. PMID:27231914

  14. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Clingerman, Bruce J.; Doan, Tien M.; Keskula, Donald H.

    2002-01-01

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  15. Assessment of Literature Related to Combustion Appliance Venting Systems

    SciTech Connect

    Rapp, V. H.; Less, B. D.; Singer, B. C.; Stratton, J. C.; Wray, C. P.

    2015-02-01

    In many residential building retrofit programs, air tightening to increase energy efficiency is often constrained by safety concerns with naturally vented combustion appliances. Tighter residential buildings more readily depressurize when exhaust equipment is operated, making combustion appliances more prone to backdraft or spill combustion exhaust into the living space. Several measures, such as installation guidelines, vent sizing codes, and combustion safety diagnostics, are in place with the intent to prevent backdrafting and combustion spillage, but the diagnostics conflict and the risk mitigation objective is inconsistent. This literature review summarizes the metrics and diagnostics used to assess combustion safety, documents their technical basis, and investigates their risk mitigations. It compiles information from the following: codes for combustion appliance venting and installation; standards and guidelines for combustion safety diagnostics; research evaluating combustion safety diagnostics; research investigating wind effects on building depressurization and venting; and software for simulating vent system performance.

  16. Staged venting of fuel cell system during rapid shutdown

    DOEpatents

    Keskula, Donald H.; Doan, Tien M.; Clingerman, Bruce J.

    2004-09-14

    A venting methodology and system for rapid shutdown of a fuel cell apparatus of the type used in a vehicle propulsion system. H.sub.2 and air flows to the fuel cell stack are slowly bypassed to the combustor upon receipt of a rapid shutdown command. The bypass occurs over a period of time (for example one to five seconds) using conveniently-sized bypass valves. Upon receipt of the rapid shutdown command, the anode inlet of the fuel cell stack is instantaneously vented to a remote vent to remove all H.sub.2 from the stack. Airflow to the cathode inlet of the fuel cell stack gradually diminishes over the bypass period, and when the airflow bypass is complete the cathode inlet is also instantaneously vented to a remote vent to eliminate pressure differentials across the stack.

  17. Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

    PubMed

    Ahmadi, Mahdi; John, Kuruvilla

    2015-12-01

    Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone

  18. Submarine radial vents on Mauna Loa Volcano, Hawai'i

    USGS Publications Warehouse

    Wanless, V. Dorsey; Garcia, M.O.; Trusdell, F.A.; Rhodes, J.M.; Norman, M.D.; Weis, Dominique; Fornari, D.J.; Kurz, M.D.; Guillou, Herve

    2006-01-01

    A 2002 multibeam sonar survey of Mauna Loa's western flank revealed ten submarine radial vents and three submarine lava flows. Only one submarine radial vent was known previously. The ages of these vents are constrained by eyewitness accounts, geologic relationships, Mn-Fe coatings, and geochemical stratigraphy; they range from 128 years B.P. to possibly 47 ka. Eight of the radial vents produced degassed lavas despite eruption in water depths sufficient to inhibit sulfur degassing. These vents formed truncated cones and short lava flows. Two vents produced undegassed lavas that created “irregular” cones and longer lava flows. Compositionally and isotopically, the submarine radial vent lavas are typical of Mauna Loa lavas, except two cones that erupted alkalic lavas. He-Sr isotopes for the radial vent lavas follow Mauna Loa's evolutionary trend. The compositional and isotopic heterogeneity of these lavas indicates most had distinct parental magmas. Bathymetry and acoustic backscatter results, along with photography and sampling during four JASON2 dives, are used to produce a detailed geologic map to evaluate Mauna Loa's submarine geologic history. The new map shows that the 1877 submarine eruption was much larger than previously thought, resulting in a 10% increase for recent volcanism. Furthermore, although alkalic lavas were found at two radial vents, there is no systematic increase in alkalinity among these or other Mauna Loa lavas as expected for a dying volcano. These results refute an interpretation that Mauna Loa's volcanism is waning. The submarine radial vents and flows cover 29 km2 of seafloor and comprise a total volume of ∼2×109 m3 of lava, reinforcing the idea that submarine lava eruptions are important in the growth of oceanic island volcanoes even after they emerged above sea level.

  19. Spatial density analysis of volcanic vents in the Concepción volcanic complex, Nicaragua

    NASA Astrophysics Data System (ADS)

    Saballos, J. A.; Kiyosugi, K.; Connor, C.; Connor, L.

    2011-12-01

    We have applied a bivariate Gaussian kernel function to estimate spatial density of volcanic vents associated to the Concepción Volcanic Complex, CVC. Our dataset consists of 36 known vents distributed on an area 11.0 km (N-S) by 11.3 km (E-W), and whose age of formation is unknown. There are 3 known vents on the western side of the CVC, 21 in the central area, and 12 in the eastern side. All these three regions describe preferentially N-S elongate zones. Concepción is the most active composite volcano in Nicaragua and forms the northwestern side of the Ometepe Island with a total population estimated to be ~33,000, and with the vast majority living very near the volcano. Thus there is an immediate need for estimating the probabilistic hazard associated with areas more prone to the formation of new volcanic vents and how they compare to the location of population centers. We computed the spatial density using the sum of the asymptotic mean squared error (SAMSE), and the least-square cross validation (LSCV) algorithms, both available in the freely-distributed R statistical software library. Both algorithms produce grossly similar spatial density, but with significantly different emphasis on the three elongate vent zones. The SAMSE algorithm yields a spatial vent density of 3x10-2 - 4x10-4 event/km2 between the 1st and 99th percentiles, and an elliptical bandwidth of 2.6 km in the N-S direction and 2.2 km in the E-W. The LSCV algorithm produces a spatial vent density of 5x10-2 - 5x10-4 event/km2 between the 1st and 99th percentiles, and a highly eccentric bandwidth with axis of 2.8 km in the N-S direction and 0.8 km in the E-W. The vent spatial density map produced by the SAMSE algorithm embraces all the vents below the 95th percentile with a spatial density > 2x10-3 event/km2, and the shape of the map is quite homogeneous and not particularly sensitive to local geology or tectonic setting. The spatial density produced by the LSCV algorithm shows three parallel

  20. 40 CFR 63.115 - Process vent provisions-methods and procedures for process vent group determination.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... vent stream is halogenated, the mass emission rate of halogen atoms contained in organic compounds shall be calculated. (A) The vent stream concentration of each organic compound containing halogen atoms... atoms: ER22AP94.204 where: E=mass of halogen atoms, dry basis, kilogram per hour. K2 = Constant,...

  1. 75 FR 10301 - MMS Information Collection Activity: 1010-0006, Leasing of Sulphur or Oil and Gas in the Outer...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-05

    ...-0013] MMS Information Collection Activity: 1010-0006, Leasing of Sulphur or Oil and Gas in the Outer Continental Shelf and Outer Continental Shelf Oil and Gas Leasing, Extension of a Collection; Submitted for... 30 CFR 256, ``Leasing of Sulphur or Oil and Gas in the Outer Continental Shelf,'' and 30 CFR...

  2. 75 FR 13570 - MMS Information Collection Activity: 1010-0043, Oil and Gas Well-Workover Operations, Renewal of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-22

    ... Minerals Management Service MMS Information Collection Activity: 1010-0043, Oil and Gas Well- Workover... (ICR) concerns the paperwork requirements in the regulations under 30 CFR 250, Subpart F, ``Oil and Gas... return address. SUPPLEMENTARY INFORMATION: Title: 30 CFR 250, Subpart F, Oil and Gas...

  3. 78 FR 68082 - Information Collection Activities: Oil and Gas Well-Workover Operations; Submitted for Office of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-13

    ...; 134E1700D2 EEEE500000 ET1SF0000.DAQ000] Information Collection Activities: Oil and Gas Well-Workover... requirements in the regulations under Subpart F, Oil and Gas Well- Workover Operations. This notice also... INFORMATION: Title: 30 CFR Part 250, Subpart F, Oil and Gas Well-Workover Operations. OMB Control Number:...

  4. 75 FR 7474 - CenterPoint Energy Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-19

    ... Energy Regulatory Commission CenterPoint Energy Gas Transmission Company; Prior Notice of Activity Under Blanket Certificate February 3, 2010. On January 26, 2010 CenterPoint Energy Gas Transmission Company... Energy Regulatory Commission's (Commission) regulations under the Natural Gas Act, and CEGT's...

  5. Survey of oil and gas activities on federal wildlife refuges and waterfowl production areas

    SciTech Connect

    Ethridge, M.; Guerrieri, U.

    1983-01-01

    An analysis of survey data provides empirical evidence of the effects of oil and gas activities on federal wildlife refuges. The paper reports the results of a systematic survey of units of the National Wildlife Refuge System by the American Petroleum Institute in the form of questionnaires sent to refuge managers. The data suggest that oil and gas operations have had little or no adverse effect on wildlife on most refuges and Waterfowl Protection Areas, that oil and gas activities have detracted little from and have often enhanced other economic and recreational uses which occur on the refuges, and that appropriate regulations, stipulations, and restrictions are a key government management tool for protecting wildlife and other refuge resources. 3 figures, 44 tables.

  6. Deep-Sea Hydrothermal-Vent Sampler

    NASA Technical Reports Server (NTRS)

    Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.

    2008-01-01

    An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea hydrothermal- vent samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the hydrothermal plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of vent fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral

  7. Comparative Composition, Diversity and Trophic Ecology of Sediment Macrofauna at Vents, Seeps and Organic Falls

    PubMed Central

    Bernardino, Angelo F.; Levin, Lisa A.; Thurber, Andrew R.; Smith, Craig R.

    2012-01-01

    Sediments associated with hydrothermal venting, methane seepage and large organic falls such as whale, wood and plant detritus create deep-sea networks of soft-sediment habitats fueled, at least in part, by the oxidation of reduced chemicals. Biological studies at deep-sea vents, seeps and organic falls have looked at macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sediment macrobenthos in various reducing ecosystems. Here we review key similarities and differences in the sediment-dwelling assemblages of each system with the goals of (1) generating a predictive framework for the exploration and study of newly identified reducing habitats, and (2) identifying taxa and communities that overlap across ecosystems. We show that deep-sea seep, vent and organic-fall sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiont-associated) and background fauna. Community-level comparisons reveal that vent, seep and organic-fall macrofauna are very distinct in terms of composition at the family level, although they share many dominant taxa among these highly sulphidic habitats. Stress gradients are good predictors of macrofaunal diversity at some sites, but habitat heterogeneity and facilitation often modify community structure. The biogeochemical differences across ecosystems and within habitats result in wide differences in organic utilization (i.e., food sources) and in the prevalence of chemosynthesis-derived nutrition. In the Pacific, vents, seeps and organic-falls exhibit distinct macrofaunal assemblages at broad-scales contributing to ß diversity. This has important implications for the conservation of reducing ecosystems, which face growing threats from human activities. PMID:22496753

  8. Interrelationship of fluid venting and structural evolution: Alvin observations from the frontal accretionary prism, Oregon

    SciTech Connect

    Moore, J.C.; Orange, D. ); Kulm, L.D. )

    1990-06-10

    Seismic reflection and Sea Beam bathymetric data plus submarine geological measurements define a ramp anticline at the deformatoin front of the central Oregon subduction zone. At its northern termination the ramp anticline is deeply incised by a large 500-m-deep submarine canyon and cut by a probable backthrust. To the south along the strike of the fold, a smaller submarine canyon shallowly erodes the anticline, and backthrusting is not apparent in the submersible observations. Two Alvin dives along a transect through the southern canyon show active fluid vents demarked by biological communities at the frontal thrust and at the breached crest of the anticline. Along a northern transect, encompassing the large submarine canyon, 10 Alvin dives indicated no venting on the formal thrust, limited venting in the canyon, but numerous biological communities along a scarp interpreted as the surface trace of the backthrust. These observations suggest a scenario of vent and structural-geomorphic development consisting of (1) frontal thrust faulting and associated venting, facilitated by high fluid pressure; (2) erosion of the oversteepened seaward flank of the ramp anticline assisted by seepage forces and leading to fluid flow out of stratigraphically controlled conduits in the limbs of the overthrust deposits; (3) locking of the frontal thrust due to dewatering or a local decrease in wedge taper associated with development of the large canyon, leading to failure along the backthrust; and (4) redirection of fluid flow by the backthrust. Thus, within {le}0.3 m.y., deformation of the relatively permeable sediments of the Oregon margin results in stratigraphically controlled flow being partially captured by faults.

  9. Comparative composition, diversity and trophic ecology of sediment macrofauna at vents, seeps and organic falls.

    PubMed

    Bernardino, Angelo F; Levin, Lisa A; Thurber, Andrew R; Smith, Craig R

    2012-01-01

    Sediments associated with hydrothermal venting, methane seepage and large organic falls such as whale, wood and plant detritus create deep-sea networks of soft-sediment habitats fueled, at least in part, by the oxidation of reduced chemicals. Biological studies at deep-sea vents, seeps and organic falls have looked at macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sediment macrobenthos in various reducing ecosystems. Here we review key similarities and differences in the sediment-dwelling assemblages of each system with the goals of (1) generating a predictive framework for the exploration and study of newly identified reducing habitats, and (2) identifying taxa and communities that overlap across ecosystems. We show that deep-sea seep, vent and organic-fall sediments are highly heterogeneous. They sustain different geochemical and microbial processes that are reflected in a complex mosaic of habitats inhabited by a mixture of specialist (heterotrophic and symbiont-associated) and background fauna. Community-level comparisons reveal that vent, seep and organic-fall macrofauna are very distinct in terms of composition at the family level, although they share many dominant taxa among these highly sulphidic habitats. Stress gradients are good predictors of macrofaunal diversity at some sites, but habitat heterogeneity and facilitation often modify community structure. The biogeochemical differences across ecosystems and within habitats result in wide differences in organic utilization (i.e., food sources) and in the prevalence of chemosynthesis-derived nutrition. In the Pacific, vents, seeps and organic-falls exhibit distinct macrofaunal assemblages at broad-scales contributing to ß diversity. This has important implications for the conservation of reducing ecosystems, which face growing threats from human activities.

  10. Performance analysis of no-vent fill process for liquid hydrogen tank in terrestrial and on-orbit environments

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Li, Yanzhong; Zhang, Feini; Ma, Yuan

    2015-12-01

    Two finite difference computer models, aiming at the process predictions of no-vent fill in normal gravity and microgravity environments respectively, are developed to investigate the filling performance in a liquid hydrogen (LH2) tank. In the normal gravity case model, the tank/fluid system is divided into five control volume including ullage, bulk liquid, gas-liquid interface, ullage-adjacent wall, and liquid-adjacent wall. In the microgravity case model, vapor-liquid thermal equilibrium state is maintained throughout the process, and only two nodes representing fluid and wall regions are applied. To capture the liquid-wall heat transfer accurately, a series of heat transfer mechanisms are considered and modeled successively, including film boiling, transition boiling, nucleate boiling and liquid natural convection. The two models are validated by comparing their prediction with experimental data, which shows good agreement. Then the two models are used to investigate the performance of no-vent fill in different conditions and several conclusions are obtained. It shows that in the normal gravity environment the no-vent fill experiences a continuous pressure rise during the whole process and the maximum pressure occurs at the end of the operation, while the maximum pressure of the microgravity case occurs at the beginning stage of the process. Moreover, it seems that increasing inlet mass flux has an apparent influence on the pressure evolution of no-vent fill process in normal gravity but a little influence in microgravity. The larger initial wall temperature brings about more significant liquid evaporation during the filling operation, and then causes higher pressure evolution, no matter the filling process occurs under normal gravity or microgravity conditions. Reducing inlet liquid temperature can improve the filling performance in normal gravity, but cannot significantly reduce the maximum pressure in microgravity. The presented work benefits the

  11. The Development of a New Practical Activity: Using Microorganisms to Model Gas Cycling

    ERIC Educational Resources Information Center

    Redfern, James; Burdass, Dariel; Verran, Joanna

    2014-01-01

    For many in the school science classroom, the term "microbiology" has become synonymous with "bacteriology". By overlooking other microbes, teachers may miss out on powerful practical tools. This article describes the development of an activity that uses algae and yeast to demonstrate gas cycling, and presents full instructions…

  12. GREENHOUSE GAS (GHG) MITIGATION AND MONITORING TECHNOLOGY PERFORMANCE: ACTIVITIES OF THE GHG TECHNOLOGY VERIFICATION CENTER

    EPA Science Inventory

    The paper discusses greenhouse gas (GHG) mitigation and monitoring technology performance activities of the GHG Technology Verification Center. The Center is a public/private partnership between Southern Research Institute and the U.S. EPA's Office of Research and Development. It...

  13. T & I--Gas Welding. Kit No. 68. Instructor's Manual [and] Student Learning Activity Guide.

    ERIC Educational Resources Information Center

    Lanford, Frank

    An instructor's manual and student activity guide on gas welding are provided in this set of prevocational education materials which focuses on the occupational cluster of trade and industry. (This set of materials is one of ninety-two prevocational education sets arranged around a cluster of seven vocational offerings: agriculture, home…

  14. 26 CFR 1.263A-13 - Oil and gas activities.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... is a well drilled solely to determine the location and delineation of offshore hydrocarbon deposits..., drilling ship, or an offshore drilling platform). (ii) Improvement unit. To the extent section 614 costs... 26 Internal Revenue 3 2011-04-01 2011-04-01 false Oil and gas activities. 1.263A-13 Section...

  15. Atlantic update, July 1986--June 1990: Outer Continental Shelf oil and gas activities

    SciTech Connect

    Karpas, R.M.; Gould, G.J.

    1990-10-01

    This report describes outer continental shelf oil and gas activities in the Atlantic Region. This edition of the Atlantic Update includes an overview of the Mid-Atlantic Planning Area and a summary of the Manteo Prospect off-shore North Carolina. 6 figs., 8 tabs.

  16. Assessment and Design of Water Quality Monitoring Networks with respect to Shale Gas Activities in Pennsylvania

    NASA Astrophysics Data System (ADS)

    Arjmand, S.; Abad, J. D.; Brantley, S. L.

    2013-12-01

    Over the past few years, hydraulic fracturing and horizontal drilling techniques have been extensively used to extract shale gas from the Marcellus Shale. Likewise, several environmental violations that have been repeatedly reported in drilling sites have created greater awareness on potentially adverse environmental impacts of shale gas. Long-term monitoring in the Marcellus Shale is the key to maintain and improve the quality of water supplies in future. Currently, the absence of an efficient water quality monitoring network prevents the detection and source identification of contaminants associated with shale gas activities. Evaluation and re-design of monitoring networks from time to time is a major step towards efficient water resources planning and management. In this study, we assessed the performance of the current water quality monitoring network with respect to the shale gas development in Pennsylvania. For better evaluation, the Oil and Gas Compliance Report by the Pennsylvania Department of Environmental Protection between January 2005 and May 2013 was compiled. Using statistical and GIS methods each violation item was examined against the number and location of sensors in the current monitoring network. The results helped identify the adequacy of the number of sensors to detect the potential contamination. Moreover, to improve the performance and to lower the long-term monitoring costs, we re-designed the network using optimization methods. This optimal system maximizes the understanding of the aquifer condition and investigates the shale gas industry impacts on shallow aquifers, and it is applicable to other watersheds with shale oil and gas drilling activities.

  17. Alteration of natural (37)Ar activity concentration in the subsurface by gas transport and water infiltration.

    PubMed

    Guillon, Sophie; Sun, Yunwei; Purtschert, Roland; Raghoo, Lauren; Pili, Eric; Carrigan, Charles R

    2016-05-01

    High (37)Ar activity concentration in soil gas is proposed as a key evidence for the detection of underground nuclear explosion by the Comprehensive Nuclear Test-Ban Treaty. However, such a detection is challenged by the natural background of (37)Ar in the subsurface, mainly due to Ca activation by cosmic rays. A better understanding and improved capability to predict (37)Ar activity concentration in the subsurface and its spatial and temporal variability is thus required. A numerical model integrating (37)Ar production and transport in the subsurface is developed, including variable soil water content and water infiltration at the surface. A parameterized equation for (37)Ar production in the first 15 m below the surface is studied, taking into account the major production reactions and the moderation effect of soil water content. Using sensitivity analysis and uncertainty quantification, a realistic and comprehensive probability distribution of natural (37)Ar activity concentrations in soil gas is proposed, including the effects of water infiltration. Site location and soil composition are identified as the parameters allowing for a most effective reduction of the possible range of (37)Ar activity concentrations. The influence of soil water content on (37)Ar production is shown to be negligible to first order, while (37)Ar activity concentration in soil gas and its temporal variability appear to be strongly influenced by transient water infiltration events. These results will be used as a basis for practical CTBTO concepts of operation during an OSI.

  18. Carbon Dioxide Washout Testing Using Various Inlet Vent Configurations in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Korona, F. Adam; Norcross, Jason; Conger, Bruce; Navarro, Moses

    2014-01-01

    Requirements for using a space suit during ground testing include providing adequate carbon dioxide (CO2) washout for the suited subject. Acute CO2 exposure can lead to symptoms including headache, dyspnea, lethargy, and eventually unconsciousness or even death. Symptoms depend on several factors including inspired partial pressure of CO2 (ppCO2), duration of exposure, metabolic rate of the subject, and physiological differences between subjects. Computational Fluid Dynamics (CFD) analysis has predicted that the configuration of the suit inlet vent has a significant effect on oronasal CO2 concentrations. The main objective of this test was to characterize inspired oronasal ppCO2 for a variety of inlet vent configurations in the Mark-III suit across a range of workload and flow rates. Data and trends observed during testing along with refined CFD models will be used to help design an inlet vent configuration for the Z-2 space suit. The testing methodology used in this test builds upon past CO2 washout testing performed on the Z-1 suit, Rear Entry I-Suit, and the Enhanced Mobility Advanced Crew Escape Suit. Three subjects performed two test sessions each in the Mark-III suit to allow for comparison between tests. Six different helmet inlet vent configurations were evaluated during each test session. Suit pressure was maintained at 4.3 psid. Suited test subjects walked on a treadmill to generate metabolic workloads of approximately 2000 and 3000 BTU/hr. Supply airflow rates of 6 and 4 actual cubic feet per minute were tested at each workload. Subjects wore an oronasal mask with an open port in front of the mouth and were allowed to breathe freely. Oronasal ppCO2 was monitored real-time via gas analyzers with sampling tubes connected to the oronasal mask. Metabolic rate was calculated from the CO2 production measured by an additional gas analyzer at the air outlet from the suit. Real-time metabolic rate measurements were used to adjust the treadmill workload to meet

  19. CO2 Washout Testing Using Various Inlet Vent Configurations in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Korona, F. Adam; Norcross, Jason; Conger, Bruce; Navarro, Moses

    2014-01-01

    breathe freely. Oronasal ppCO2 will be monitored real-time via gas analyzers with sampling tubes connected to the oronasal mask. Metabolic rate will be calculated from the total oxygen consumption and CO2 production measured by additional gas analyzers at the air outlet from the suit. Real-time metabolic rate measurements will be used to adjust the treadmill workload to meet target metabolic rates. This paper provides detailed descriptions of the test hardware, methodology and results, as well as implications for future inlet vent design and ground testing in the Mark-III.

  20. CO2 Washout Testing Using Various Inlet Vent Configurations in the Mark-III Space Suit

    NASA Technical Reports Server (NTRS)

    Korona, F. Adam; Norcross, Jason; Conger, Bruce; Navarro, Moses

    2014-01-01

    Requirements for using a space suit during ground testing include providing adequate carbon dioxide (CO2) washout for the suited subject. Acute CO2 exposure can lead to symptoms including headache, dyspnea, lethargy and eventually unconsciousness or even death. Symptoms depend on several factors including inspired partial pressure of CO2 (ppCO2), duration of exposure, metabolic rate of the subject and physiological differences between subjects. Computational Fluid Dynamic (CFD) analysis has predicted that the configuration of the suit inlet vent has a significant effect on oronasal CO2 concentrations. The main objective of this test was to characterize inspired oronasal ppCO2 for a variety of inlet vent configurations in the Mark-III suit across a range of workload and flow rates. Data and trends observed during testing along with refined CFD models will be used to help design an inlet vent configuration for the Z-2 space suit. The testing methodology used in this test builds upon past CO2 washout testing performed on the Z-1 suit, Rear Entry I-Suit (REI) and the Enhanced Mobility Advanced Crew Escape Suit (EM-ACES). Three subjects performed two test sessions each in the Mark-III suit to allow for comparison between tests. Six different helmet inlet vent configurations were evaluated during each test session. Suit pressure was maintained at 4.3 psid. Suited test subjects walked on a treadmill to generate metabolic workloads of approximately 2000 and 3000 BTU/hr. Supply airflow rates of 6 and 4 actual cubic feet per minute (ACFM) were tested at each workload. Subjects wore an oronasal mask with an open port in front of the mouth and were allowed to breathe freely. Oronasal ppCO2 was monitored real-time via gas analyzers with sampling tubes connected to the oronasal mask. Metabolic rate was calculated from the total oxygen consumption and CO2 production measured by additional gas analyzers at the air outlet from the suit. Realtime metabolic rate measurements were