DICHOTOMY OF SOLAR CORONAL JETS: STANDARD JETS AND BLOWOUT JETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.

2010-09-01

By examining many X-ray jets in Hinode/X-Ray Telescope coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H{alpha} macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major coronal mass ejections. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jetsmore » that were also caught in He II 304 A snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T {approx} 10{sup 4} - 10{sup 5} K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.« less

Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

NASA Technical Reports Server (NTRS)

Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

2010-01-01

By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

Numerical simulation of water and sand blowouts when penetrating through shallow water flow formations in deep water drilling

NASA Astrophysics Data System (ADS)

Ren, Shaoran; Liu, Yanmin; Gong, Zhiwu; Yuan, Yujie; Yu, Lu; Wang, Yanyong; Xu, Yan; Deng, Junyu

2018-02-01

In this study, we applied a two-phase flow model to simulate water and sand blowout processes when penetrating shallow water flow (SWF) formations during deepwater drilling. We define `sand' as a pseudo-component with high density and viscosity, which can begin to flow with water when a critical pressure difference is attained. We calculated the water and sand blowout rates and analyzed the influencing factors from them, including overpressure of the SWF formation, as well as its zone size, porosity and permeability, and drilling speed (penetration rate). The obtained data can be used for the quantitative assessment of the potential severity of SWF hazards. The results indicate that overpressure of the SWF formation and its zone size have significant effects on SWF blowout. A 10% increase in the SWF formation overpressure can result in a more than 90% increase in the cumulative water blowout and a 150% increase in the sand blowout when a typical SWF sediment is drilled. Along with the conventional methods of well flow and pressure control, chemical plugging, and the application of multi-layer casing, water and sand blowouts can be effectively reduced by increasing the penetration rate. As such, increasing the penetration rate can be a useful measure for controlling SWF hazards during deepwater drilling.

The Hydraulic Mechanism in the Orbital Blowout Fracture Because of a High-Pressure Air Gun Injury.

PubMed

Kang, Seok Joo; Chung, Eui Han

2015-10-01

There are 2 predominant mechanisms that are used to explain the pathogenesis of orbital blowout fracture; these include hydraulic and buckling mechanisms. Still, however, its pathophysiology remains uncertain. To date, studies in this series have been conducted using dry skulls, cadavers, or animals. But few clinical studies have been conducted to examine whether the hydraulic mechanism is involved in the occurrence of pure orbital blowout fracture. The authors experienced a case of a 52-year-old man who had a pure medial blowout fracture after sustaining an eye injury because of a high-pressure air gun. Our case suggests that surgeons should be aware of the possibility that the hydraulic mechanism might be involved in the blowout fracture in patients presenting with complications, such as limitation of eye movement, diplopia, and enophthalmos.

Development of 3000 m Subsea Blowout Preventer Experimental Prototype

NASA Astrophysics Data System (ADS)

Cai, Baoping; Liu, Yonghong; Huang, Zhiqian; Ma, Yunpeng; Zhao, Yubin

2017-12-01

A subsea blowout preventer experimental prototype is developed to meet the requirement of training operators, and the prototype consists of hydraulic control system, electronic control system and small-sized blowout preventer stack. Both the hydraulic control system and the electronic system are dual-mode redundant systems. Each system works independently and is switchable when there are any malfunctions. And it significantly improves the operation reliability of the equipment.

Gas-blowout control by water injection through relief wells: a theoretical analysis. [Injection of water into the formation through relief wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lehner, F.; Williamson, A.S.

1974-08-01

Koninklijke/Shell Exploratie en Produktie Laboratorium in The Netherlands suggests bringing a gas blowout under control by injecting water into the formation through relief wells. By avoiding direct contact between relief well and blowout well, this technique reduces the inflow of gas by creating sufficient back pressure in the formation itself. The mechanics of the technique are considered.

Orbital blowout fracture location in Japanese and Chinese patients.

PubMed

Sun, Michelle T; Wu, Wencan; Watanabe, Akihide; Kakizaki, Hirohiko; Chen, Ben; Ueda, Kosuke; Katori, Nobutada; Takahashi, Yasuhiro; Selva, Dinesh

2015-01-01

To characterize the location of orbital blowout fractures in Asian individuals. This was a retrospective review of 470 consecutive Asian patients with orbital blowout fractures who presented to four tertiary care hospitals in Japan and China. Computed tomography (CT) characterized the location and severity of fractures involving the medial wall, the orbital floor, and/or the maxilloethmoidal strut. A total of 475 orbital blowout fractures were identified. More than one fracture location was involved in 19% of all cases. The medial orbital wall was the most commonly involved location, presenting in 29 cases (61%), of which 204 (43%) were isolated medial blowout fractures. The orbital floor was the second most common location involved, present in 226 cases (48%) with 150 isolated orbital floor fractures (32%), while the maxilloethmoidal strut was involved in 45 cases (9%) with 30 of those being isolated strut fractures (6%). The majority of fractures (62%) were classified as moderately severe, whilst 14% were mild, and 24% were severe. Associated nasal fractures were present in 16% of the cases. Orbital blowout fractures in Japanese and Chinese individuals occur most commonly in the medial wall. This is in contrast to previous reports on white individuals, who tend to sustain fractures involving the orbital floor rather than the medial wall.

The cool component and the dichotomy, lateral expansion, and axial rotation of solar X-ray jets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.

2013-06-01

We present results from a study of 54 polar X-ray jets that were observed in coronal X-ray movies from the X-ray Telescope on Hinode and had simultaneous coverage in movies of the cooler transition region (T ∼ 10{sup 5} K) taken in the He II 304 Å band of the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory. These dual observations verify the standard-jet/blowout-jet dichotomy of polar X-ray jets previously found primarily from XRT movies alone. In accord with models of blowout jets and standard jets, the AIA 304 Å movies show a cool (T ∼ 10{sup 5} K) componentmore » in nearly all blowout X-ray jets and in a small minority of standard X-ray jets, obvious lateral expansion in blowout X-ray jets but none in standard X-ray jets, and obvious axial rotation in both blowout X-ray jets and standard X-ray jets. In our sample, the number of turns of axial rotation in the cool-component standard X-ray jets is typical of that in the blowout X-ray jets, suggesting that the closed bipolar magnetic field in the jet base has substantial twist not only in all blowout X-ray jets but also in many standard X-ray jets. We point out that our results for the dichotomy, lateral expansion, and axial rotation of X-ray jets add credence to published speculation that type-II spicules are miniature analogs of X-ray jets, are generated by granule-size emerging bipoles, and thereby carry enough energy to power the corona and solar wind.« less

Delayed onset porous polyethylene implant-related inflammation after orbital blowout fracture repair: four case reports.

PubMed

Aryasit, Orapan; Ng, Danny S; Goh, Alice S C; Woo, Kyung In; Kim, Yoon-Duck

2016-07-07

Porous polyethylene implants are commonly used in orbital blowout fracture repair because of purported biocompatibility, durability, and low frequency of complications. Delayed inflammation related to porous polyethylene sheet implants is very rare and no case series of this condition have been reported. This is a retrospective review of clinical presentations, radiographic findings, histopathological findings, treatments, and outcomes of patients who developed delayed complications in orbital blowout fracture repair using porous polyethylene sheets. Four male patients were included with a mean age of 49 years (range 35-69 years). Blowout fracture repair was complicated with implant-related inflammation 10 months, 2 years, 3 years, and 8 years after surgery. Chronic and subacute orbital inflammatory signs were noted in two patients and acute fulminant orbital inflammation was found in two patients. Three patients developed peri-implant abscesses and one patient had a soft tissue mass around the implant. All patients underwent implant removal and two of these patients with paranasal sinusitis had sinus surgery. Histopathological findings revealed chronic inflammatory changes with fibrosis, and one patient had foreign body granuloma with culture positive Staphylococcus aureus. Delayed complications with porous polyethylene sheets used in orbital blowout fracture repair may occur many years following the initial surgery in immunocompetent patients. Low-grade or fulminant inflammation could complicate blowout fracture repair related with the implant.

PHYSICAL PARAMETERS OF STANDARD AND BLOWOUT JETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pucci, Stefano; Romoli, Marco; Poletto, Giannina

2013-10-10

The X-ray Telescope on board the Hinode mission revealed the occurrence, in polar coronal holes, of much more numerous jets than previously indicated by the Yohkoh/Soft X-ray Telescope. These plasma ejections can be of two types, depending on whether they fit the standard reconnection scenario for coronal jets or if they include a blowout-like eruption. In this work, we analyze two jets, one standard and one blowout, that have been observed by the Hinode and STEREO experiments. We aim to infer differences in the physical parameters that correspond to the different morphologies of the events. To this end, we adoptmore » spectroscopic techniques and determine the profiles of the plasma temperature, density, and outflow speed versus time and position along the jets. The blowout jet has a higher outflow speed, a marginally higher temperature, and is rooted in a stronger magnetic field region than the standard event. Our data provide evidence for recursively occurring reconnection episodes within both the standard and the blowout jet, pointing either to bursty reconnection or to reconnection occurring at different locations over the jet lifetimes. We make a crude estimate of the energy budget of the two jets and show how energy is partitioned among different forms. Also, we show that the magnetic energy that feeds the blowout jet is a factor of 10 higher than the magnetic energy that fuels the standard event.« less

Kill operation requires thorough analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abel, L.W.

1995-05-15

Full control of a blowout well requires a properly designed post-capping kill operation because failures in regaining well control usually occur during the kill operation, not during capping. Capping (the installation of pressure control or diverter equipment on the wellhead) is generally very reliable in gaining control of a blowout well. The following techniques are some of the viable means of killing blowout wells once the capping assemblies are in place: direct shut in of the flow; bullheading; momentum kill; volumetric control for migration of fluids or lubrication after migration ceases; and dynamic kills (friction-based dynamic kills or mass flowmore » rate kills) The objective of most post-capping operations is to stop the flow and put the well under hydrostatic control. The means of killing a blowout once capping assemblies are in place should be chosen with care to avoid problems such as cratering, equipment failure, and underground blowouts. The particular circumstances and well integrity will dictate which kill method will be the most viable. Each of these five methods are explained.« less

Development of an automatic subsea blowout preventer stack control system using PLC based SCADA.

PubMed

Cai, Baoping; Liu, Yonghong; Liu, Zengkai; Wang, Fei; Tian, Xiaojie; Zhang, Yanzhen

2012-01-01

An extremely reliable remote control system for subsea blowout preventer stack is developed based on the off-the-shelf triple modular redundancy system. To meet a high reliability requirement, various redundancy techniques such as controller redundancy, bus redundancy and network redundancy are used to design the system hardware architecture. The control logic, human-machine interface graphical design and redundant databases are developed by using the off-the-shelf software. A series of experiments were performed in laboratory to test the subsea blowout preventer stack control system. The results showed that the tested subsea blowout preventer functions could be executed successfully. For the faults of programmable logic controllers, discrete input groups and analog input groups, the control system could give correct alarms in the human-machine interface. Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.

A small-scale eruption leading to a blowout macrospicule jet in an on-disk coronal hole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, Mitzi; Sterling, Alphonse C.; Moore, Ronald L.

2014-03-01

We examine the three-dimensional magnetic structure and dynamics of a solar EUV-macrospicule jet that occurred on 2011 February 27 in an on-disk coronal hole. The observations are from the Solar Dynamics Observatory (SDO) Atmospheric Imaging Assembly (AIA) and the SDO Helioseismic and Magnetic Imager (HMI). The observations reveal that in this event, closed-field-carrying cool absorbing plasma, as in an erupting mini-filament, erupted and opened, forming a blowout jet. Contrary to some jet models, there was no substantial recently emerged, closed, bipolar-magnetic field in the base of the jet. Instead, over several hours, flux convergence and cancellation at the polarity inversionmore » line inside an evolved arcade in the base apparently destabilized the entire arcade, including its cool-plasma-carrying core field, to undergo a blowout eruption in the manner of many standard-sized, arcade-blowout eruptions that produce a flare and coronal mass ejection. Internal reconnection made bright 'flare' loops over the polarity inversion line inside the blowing-out arcade field, and external reconnection of the blowing-out arcade field with an ambient open field made longer and dimmer EUV loops on the outside of the blowing-out arcade. That the loops made by the external reconnection were much larger than the loops made by the internal reconnection makes this event a new variety of blowout jet, a variety not recognized in previous observations and models of blowout jets.« less

The use of time-series LIDAR to understand the role of foredune blowouts in coastal dune dynamics, Sefton, NW England.

NASA Astrophysics Data System (ADS)

O'Keeffe, Nicholas; Delgado-Fernandez, Irene; Aplin, Paul; Jackson, Derek; Marston, Christopher

2017-04-01

Coastal dunes are natural buffers against the threat of climate change-induced sea level rise. Their evolution is largely controlled by sediment exchanges between the geomorphic sub-units of the nearshore, beach, foredune and dune field. Coastlines characterised by multiple blowouts at the beach-dune interface may be more susceptible to coastline retreat through the enhanced landwards transport of beach and foredune sediment. This study, based in Sefton, north-west England, exploits an unprecedented temporal coverage of LIDAR surveys spanning 15 years (1999, 2008, 2010, 2013 and 2014). Established GIS techniques have been utilised to extract both the coastline (foredune toe) and the foredune crest from each LIDAR derived DTM (Digital Terrain Model). Migration of the foredune toe has been tracked over this period. Analysis of differentials between the height of the dune toe and dune crest have been used to locate the alongshore position of blowouts within the foredune. Dune sediment budgets have then been calculated for each DTM and analysis of the budgets conducted, with the coastline being compartmentalised alongshore, based on presence of blowouts within the foredune. Results indicate that sections of the coastline where blowouts are present within the foredune may be most vulnerable to coastline retreat. Temporal changes in the sediment budget within many of these sections also provides evidence that, if blowouts are present, coastline retreat continues to be a possibility even when the dune sediment budget remains positive.

Effect of Oxygen addition on altitude blowout and relight of an experimental combustor segment

NASA Technical Reports Server (NTRS)

Norgren, C. T.; Ingebo, R. D.

1974-01-01

The effect of oxygen addition on the low pressure altitude blowout limits of an experimental combustor segment was investigated. Data were obtained for two inlet-air temperatures, two inlet-airflow rates, and a constant fuel-air ratio of 0.020 with Jet A fuel. It was shown that the pressure at blowout could be reduced to correspond to an increase in altitude of 4.6 kilometers with oxygen flow rates of 8 to 16 percent by weight of the total fuel flow.

One-side riddled basin below and beyond the blowout bifurcation

NASA Astrophysics Data System (ADS)

Yang, H. L.

2000-10-01

In this Rapid Comunication we report a phenomenon of a one-side riddled basin where one side of the basin of attraction of an attractor on an invariant subspace (ISS) is globally riddled, while the other side is only locally riddled. This kind of basin appears due to the symmetry breaking with respect to the ISS. This one-side riddled basin can even persist beyond the blowout bifurcation, contrary to the previously reported riddled basins which exist only below the blowout transition. An experimental situation where this phenomenon can be expected is proposed.

Intelligent Engine Systems: Alternate Fuels Evaluation

NASA Technical Reports Server (NTRS)

Ballal, Dilip

2008-01-01

The performance and gaseous emissions were measured for a well-stirred reactor operating under lean conditions for two fuels: JP8 and a synthetic Fisher-Tropsch fuel over a range of equivalence ratios from 0.6 down to the lean blowout. The lean blowout characteristics were determined in LBO experiments at loading parameter values from 0.7 to 1.4. The lean blowout characteristics were then explored under higher loading conditions by simulating higher altitude operation with the use of nitrogen as a dilution gas for the air stream. The experiments showed that: (1) The lean blowout characteristics for the two fuels were close under both low loading and high loading conditions. (2) The combustion temperatures and observed combustion efficiencies were similar for the two fuels. (3) The gaseous emissions were similar for the two fuels and the differences in the H2O and CO2 emissions appear to be directly relatable to the C/H ratio for the fuels.

ON A CORONAL BLOWOUT JET: THE FIRST OBSERVATION OF A SIMULTANEOUSLY PRODUCED BUBBLE-LIKE CME AND A JET-LIKE CME IN A SOLAR EVENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen Yuandeng; Liu Yu; Su Jiangtao

2012-02-01

The coronal blowout jet is a peculiar category among various jet phenomena, in which the sheared base arch, often carrying a small filament, experiences a miniature version of blowout eruption that produces large-scale coronal mass ejection (CME). In this paper, we report such a coronal blowout jet with high-resolution multi-wavelength and multi-angle observations taken from Solar Dynamics Observatory, Solar Terrestrial Relations Observatory, and Big Bear Solar Observatory. For the first time, we find that simultaneous bubble-like and jet-like CMEs were dynamically related to the blowout jet that showed cool and hot components next to each other. Our observational results indicatemore » that (1) the cool component resulted from the eruption of the filament contained within the jet's base arch, and it further caused the bubble-like CME; (2) the jet-like CME was associated with the hot component, which was the outward moving heated plasma generated by the reconnection of the base arch and its ambient open field lines. On the other hand, bifurcation of the jet's cool component was also observed, which resulted from the uncoupling of the erupting filament's two legs that were highly twisted at the very beginning. Based on these results, we propose a model to interpret the coronal blowout jet, in which the external reconnection not only produces the jet-like CME, but also leads to the rising of the filament. Subsequently, internal reconnection starts underneath the rising filament and thereby causes the bubble-like CME.« less

30 CFR 250.1624 - Blowout prevention equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 2 2011-07-01 2011-07-01 false Blowout prevention equipment. 250.1624 Section 250.1624 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT... with manual overrides or alternately other devices provided to ensure capability of hydraulic...

Blowout Prevention System Events and Equipment Component Failures : 2016 SafeOCS Annual Report

DOT National Transportation Integrated Search

2017-09-22

The SafeOCS 2016 Annual Report, produced by the Bureau of Transportation Statistics (BTS), summarizes blowout prevention (BOP) equipment failures on marine drilling rigs in the Outer Continental Shelf. It includes an analysis of equipment component f...

Was the extreme and wide-spread marine oil-snow sedimentation and flocculent accumulation (MOSSFA) event during the Deepwater Horizon blow-out unique?

PubMed

Vonk, Sophie M; Hollander, David J; Murk, AlberTinka J

2015-11-15

During the Deepwater Horizon blowout, thick layers of oiled material were deposited on the deep seafloor. This large scale benthic concentration of oil is suggested to have occurred via the process of Marine Oil Snow Sedimentation and Flocculent Accumulation (MOSSFA). This meta-analysis investigates whether MOSSFA occurred in other large oil spills and identifies the main drivers of oil sedimentation. MOSSFA was found to have occurred during the IXTOC I blowout and possibly during the Santa Barbara blowout. Unfortunately, benthic effects were not sufficiently studied for the 52 spills we reviewed. However, based on the current understanding of drivers involved, we conclude that MOSSFA and related benthic contamination may be widespread. We suggest to collect and analyze sediment cores at specific spill locations, as improved understanding of the MOSSFA process will allow better informed spill responses in the future, taking into account possible massive oil sedimentation and smothering of (deep) benthic ecosystems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Well blowout rates and consequences in California Oil and Gas District 4 from 1991 to 2005: Implications for geological storage of carbon dioxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jordan, Preston; Jordan, Preston D.; Benson, Sally M.

2008-05-15

Well blowout rates in oil fields undergoing thermally enhanced recovery (via steam injection) in California Oil and Gas District 4 from 1991 to 2005 were on the order of 1 per 1,000 well construction operations, 1 per 10,000 active wells per year, and 1 per 100,000 shut-in/idle and plugged/abandoned wells per year. This allows some initial inferences about leakage of CO2 via wells, which is considered perhaps the greatest leakage risk for geological storage of CO2. During the study period, 9% of the oil produced in the United States was from District 4, and 59% of this production was viamore » thermally enhanced recovery. There was only one possible blowout from an unknown or poorly located well, despite over a century of well drilling and production activities in the district. The blowout rate declined dramatically during the study period, most likely as a result of increasing experience, improved technology, and/or changes in safety culture. If so, this decline indicates the blowout rate in CO2-storage fields can be significantly minimized both initially and with increasing experience over time. Comparable studies should be conducted in other areas. These studies would be particularly valuable in regions with CO2-enhanced oil recovery (EOR) and natural gas storage.« less

30 CFR 250.1625 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2011 CFR

2011-07-01

... drills. 250.1625 Section 250.1625 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND... SHELF Sulphur Operations § 250.1625 Blowout preventer system testing, records, and drills. (a) Prior to... manifold valves, upper and lower kelly cocks, and drill-string safety valves shall be pressure tested to...

30 CFR 250.617 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drills. 250.617 Section 250.617 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.617 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

30 CFR 250.1625 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2014 CFR

2014-07-01

... drills. 250.1625 Section 250.1625 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Operations § 250.1625 Blowout preventer system testing, records, and drills. (a) Prior to conducting high..., upper and lower kelly cocks, and drill-string safety valves shall be pressure tested to pipe-ram test...

30 CFR 250.616 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2012 CFR

2012-07-01

... drills. 250.616 Section 250.616 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.616 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

30 CFR 250.617 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... drills. 250.617 Section 250.617 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Gas Well-Workover Operations § 250.617 Blowout preventer system testing, records, and drills. (a) BOP... disconnecting a pressure seal in the assembly, the affected seal will be pressure tested. (c) Drills. All...

30 CFR 250.1625 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2012 CFR

2012-07-01

... drills. 250.1625 Section 250.1625 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Operations § 250.1625 Blowout preventer system testing, records, and drills. (a) Prior to conducting high..., upper and lower kelly cocks, and drill-string safety valves shall be pressure tested to pipe-ram test...

30 CFR 250.1625 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2013 CFR

2013-07-01

... drills. 250.1625 Section 250.1625 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT... Operations § 250.1625 Blowout preventer system testing, records, and drills. (a) Prior to conducting high..., upper and lower kelly cocks, and drill-string safety valves shall be pressure tested to pipe-ram test...

30 CFR 250.516 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Well-Completion Operations § 250.516 Blowout preventer system tests, inspections, and maintenance. (a...) Test affected BOP components following the disconnection or repair of any well-pressure containment... you have well-control problems. You must conduct the required BOP test as soon as possible (i.e...

Covered stent graft for treatment of a pseudoaneurysm and carotid blowout syndrome

PubMed Central

Janjua, Nazli; Alkawi, Ammar; Georgiadis, Alexandros L.; Kirmani, Jawad F.; Qureshi, Adnan I.

2008-01-01

Background Carotid blowout syndrome with pseudoaneurysm, a rapidly progressive pathology, may present emergently with massive oral hemorrhage. Use of an endograft prosthesis offers a treatment strategy with salvation of the carotid artery. Case History: A 55 year old man with advanced squamous cell carcinoma of the head and neck presented with recurrent transoral hemorrhage, requiring endovascular treatment. Technical Report: Coil embolization was initially performed with little impact on the hemorrhage. A 7 x 40 mm Fluency® Plus covered stent (Bard Peripheral Vascular, Tempe, Arizona, USA) was placed and was supplemented by a second 8 x 40 mm Fluency Plus stent, with resulting cessation of active contrast extravasation. Discussion: The risks and benefits of various treatment options of carotid pseudoaneurysm with blowout are discussed including the use or omission of antiplatelet and anticoagulant regimens, with reference to previously reported cases. Conclusion: Tandem, overlapping covered stent placement in the common carotid artery is feasible and offers a treatment option for carotid blowout syndrome. Risks of aggravation of hemorrhage versus long-term thromboembolic events without antiplatelet therapy must be considered in cases of active ongoing hemorrhage. PMID:22518207

Can we treat CO₂ well blowouts like routine plumbing problems? A study of the incidence, impact, and perception of loss of well control

DOE PAGES

Porse, Sean L.; Wade, Sarah; Hovorka, Susan D.

2014-12-31

Risk communication literature suggests that for a number of reasons, the public may perceive a risk to be greater than indicated by its statistical probability. Public concern over risk can lead to significant and costly delays in project permitting and operations. Considering these theories, media coverage of CO₂-related well blowouts in 2013 gave rise to the questions: What is the risk of CO₂ well blowouts associated with CCUS through CO₂ EOR? What is the potential public perception of those risks? What information could be used to respond to public concern? To address these questions, this study aims to: 1) providemore » a framework for understanding the nature of onshore well blowouts, 2) quantify the incidence of such events for three specific geographic regions of Texas, 3) relate this data to CCUS and findings from other studies, and 4) explore the potential implications for public perception of this risk associated with CCUS projects. While quantifying answers to these questions proved to be challenging, the results from this study suggest that (1) the perceived risk of CO₂ well blowouts may exceed the statistical risk and (2) information that could be used to address this gap could be made more readily available to the greater benefit of industry and stakeholders who support the development of CCUS as an option for addressing anthropogenic CO₂ emissions. The study also suggests approaches to best conduct such data inquiries.« less

Magnetic Untwisting in Most Solar X-Ray Jets

NASA Technical Reports Server (NTRS)

Moore, Ronald; Sterling, Alphonse; Falconer, David; Robe, Dominic

2013-01-01

From 54 X-ray jets observed in the polar coronal holes by Hinode's X-Ray Telescope (XRT) during coverage in movies from Solar Dynamic Observatory's Atmospheric Imaging Assembly (AIA) taken in its He II 304 Å band at a cadence of 12 s, we have established a basic characteristic of solar X-ray jets: untwisting motion in the spire. In this presentation, we show the progression of few of these X-ray jets in XRT images and track their untwisting in AIA He II images. From their structure displayed in their XRT movies, 19 jets were evidently standard jets made by interchange reconnection of the magnetic-arcade base with ambient open field, 32 were evidently blowout jets made by blowout eruption of the base arcade, and 3 were of ambiguous form. As was anticipated from the >10,000 km span of the base arcade in most polar X-ray jets and from the disparity of standard jets and blowout jets in their magnetic production, few of the standard X-ray jets (3 of 19) but nearly all of the blowout X-ray jets (29 of 32) carried enough cool (T is approximately 105 K) plasma to be seen in their He II movies. In the 32 X-ray jets that showed a cool component, the He II movies show 10-100 km/s untwisting motions about the axis of the spire in all 3 standard jets and in 26 of the 29 blowout jets. Evidently, the open magnetic field in nearly all blowout X-ray jets and probably in most standard X-ray jets carries transient twist. This twist apparently relaxes by propagating out along the open field as a torsional wave. High-resolution spectrograms and Dopplergrams have shown that most Type-II spicules have torsional motions of 10-30 km/s. Our observation of similar torsional motion in X-ray jets strengthens the case for Type-II spicules being made in the same way as X-ray jets, by blowout eruption of a twisted magnetic arcade in the spicule base and/or by interchange reconnection of the twisted base arcade with the ambient open field. This work was funded by NASA's Heliophysics Division through its LWS TRT Program and its Hinode Project, and by NSF through its Research Experience for Undergraduates Program.

30 CFR 250.1625 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2010 CFR

2010-07-01

... § 250.1625 Blowout preventer system testing, records, and drills. (a) Prior to conducting high-pressure tests, all BOP systems shall be tested to a pressure of 200 to 300 psi. (b) Ram-type BOP's and the choke manifold shall be pressure tested with water to a rated working pressure or as otherwise approved by the...

30 CFR 250.616 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2010 CFR

2010-07-01

... OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Well-Workover Operations § 250.616 Blowout preventer system testing, records, and drills. (a) BOP pressure tests. When you pressure test the BOP system you must conduct a low-pressure test and a high-pressure test for each...

Bubbling and on-off intermittency in bailout embeddings.

PubMed

Cartwright, Julyan H E; Magnasco, Marcelo O; Piro, Oreste; Tuval, Idan

2003-07-01

We establish and investigate the conceptual connection between the dynamics of the bailout embedding of a Hamiltonian system and the dynamical regimes associated with the occurrence of bubbling and blowout bifurcations. The roles of the invariant manifold and the dynamics restricted to it, required in bubbling and blowout bifurcating systems, are played in the bailout embedding by the embedded Hamiltonian dynamical system. The Hamiltonian nature of the dynamics is precisely the distinctive feature of this instance of a bubbling or blowout bifurcation. The detachment of the embedding trajectories from the original ones can thus be thought of as transient on-off intermittency, and noise-induced avoidance of some regions of the embedded phase space can be recognized as Hamiltonian bubbling.

Hydrogen enrichment for low-emission jet combustion

NASA Technical Reports Server (NTRS)

Clayton, R. M.

1978-01-01

Simultaneous gaseous pollutant emission indexes (g pollutant/kg fuel) for a research combustor with inlet air at 120,900 N/sq m (11.9 atm) pressure and 727 K (849 F) temperature are as low as 1.0 for NOx and CO and 0.5 for unburned HC. Emissions data are presented for hydrogen/jet fuel (JP-5) mixes and for jet fuel only for premixed equivalence ratios from lean blowout to 0.65. Minimized emissions were achieved at an equivalence ratio of 0.38 using 10-12 mass percent hydrogen in the total fuel to depress the lean blowout limit. They were not achievable with jet fuel alone because of the onset of lean blowout at an equivalence ratio too high to reduce the NOx emission sufficiently.

Prediction of the blowout of jet diffusion flames in a coflowing stream of air

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karbasi, M.; Wierzba, I.

1995-12-31

The blowout limits of a lifted diffusion flame in a coflowing stream of air are estimated using a simple model for extinction, for a range of fuels, jet diameters and co-flowing stream velocities. The proposed model uses a parameter which relates to the ratio of a time associated with the mixing processes in a turbulent jet to a characteristic chemical time. The Kolmogorov microscale of time is used as time scale in this model. It is shown that turbulent diffusion flames are quenched by excessive turbulence for a critical value of this parameter. The predicted blowout velocity of diffusion flamesmore » obtained using this model is in good agreement with the available experimental data.« less

Blowout Jets: Hinode X-Ray Jets that Don't Fit the Standard Model

NASA Technical Reports Server (NTRS)

Moore, Ronald L.; Cirtain, Jonathan W.; Sterling, Alphonse C.; Falconer, David A.

2010-01-01

Nearly half of all H-alpha macrospicules in polar coronal holes appear to be miniature filament eruptions. This suggests that there is a large class of X-ray jets in which the jet-base magnetic arcade undergoes a blowout eruption as in a CME, instead of remaining static as in most solar X-ray jets, the standard jets that fit the model advocated by Shibata. Along with a cartoon depicting the standard model, we present a cartoon depicting the signatures expected of blowout jets in coronal X-ray images. From Hinode/XRT movies and STEREO/EUVI snapshots in polar coronal holes, we present examples of (1) X-ray jets that fit the standard model, and (2) X-ray jets that do not fit the standard model but do have features appropriate for blowout jets. These features are (1) a flare arcade inside the jet-base arcade in addition to the small flare arcade (bright point) outside that standard jets have, (2) a filament of cool (T is approximately 80,000K) plasma that erupts from the core of the jetbase arcade, and (3) an extra jet strand that should not be made by the reconnection for standard jets but could be made by reconnection between the ambient unipolar open field and the opposite-polarity leg of the filament-carrying flux-rope core field of the erupting jet-base arcade. We therefore infer that these non-standard jets are blowout jets, jets made by miniature versions of the sheared-core-arcade eruptions that make CMEs

Eyebrow ptosis after blowout fracture indicates impairment of trigeminal proprioceptive evocation that induces reflex contraction of the frontalis muscle.

PubMed

Ban, Ryokuya; Matsuo, Kiyoshi; Ban, Midori; Yuzuriha, Shunsuke

2013-01-01

The mixed levator and frontalis muscles lack the interior muscle spindles normally required to induce involuntary contraction of their slow-twitch fibers. To involuntarily move the eyelid and eyebrow, voluntary contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to evoke trigeminal proprioception, which then induces reflex contraction of the levator and frontalis skeletal slow-twitch muscle fibers. The trigeminal proprioceptive nerve has a long intraorbital course from the mechanoreceptors in Müller's muscle to the superior orbital fissure. Since external force to the globe may cause impairment of trigeminal proprioceptive evocation, we confirmed how unilateral blowout fracture due to a hydraulic mechanism affects ipsilateral eyebrow movement as compared with unilateral zygomatic fracture. In 16 unilateral blowout fracture patients, eyebrow heights were measured on noninjured and injured sides in primary and 60° upward gaze and statistically compared. Eyebrow heights were also measured in primary gaze in 24 unilateral zygomatic fracture patients and statistically compared. In the blowout fracture patients, eyebrow heights on the injured side were significantly smaller than on the noninjured side in both gaze. In the zygomatic fracture patients, eyebrow heights on the injured side were significantly larger than on the noninjured side in primary gaze. Since 60° upward gaze did not recover the eyebrow ptosis observed in primary gaze in blowout fracture patients, such ptosis indicated impairment of trigeminal proprioceptive evocation and the presence of a hydraulic mechanism that may require ophthalmic examination.

Eyebrow Ptosis After Blowout Fracture Indicates Impairment of Trigeminal Proprioceptive Evocation That Induces Reflex Contraction of the Frontalis Muscle

PubMed Central

Ban, Ryokuya; Matsuo, Kiyoshi; Ban, Midori; Yuzuriha, Shunsuke

2013-01-01

Objective: The mixed levator and frontalis muscles lack the interior muscle spindles normally required to induce involuntary contraction of their slow-twitch fibers. To involuntarily move the eyelid and eyebrow, voluntary contraction of the levator nonskeletal fast-twitch muscle fibers stretches the mechanoreceptors in Müller's muscle to evoke trigeminal proprioception, which then induces reflex contraction of the levator and frontalis skeletal slow-twitch muscle fibers. The trigeminal proprioceptive nerve has a long intraorbital course from the mechanoreceptors in Müller's muscle to the superior orbital fissure. Since external force to the globe may cause impairment of trigeminal proprioceptive evocation, we confirmed how unilateral blowout fracture due to a hydraulic mechanism affects ipsilateral eyebrow movement as compared with unilateral zygomatic fracture. Methods: In 16 unilateral blowout fracture patients, eyebrow heights were measured on noninjured and injured sides in primary and 60° upward gaze and statistically compared. Eyebrow heights were also measured in primary gaze in 24 unilateral zygomatic fracture patients and statistically compared. Results: In the blowout fracture patients, eyebrow heights on the injured side were significantly smaller than on the noninjured side in both gaze. In the zygomatic fracture patients, eyebrow heights on the injured side were significantly larger than on the noninjured side in primary gaze. Conclusion: Since 60° upward gaze did not recover the eyebrow ptosis observed in primary gaze in blowout fracture patients, such ptosis indicated impairment of trigeminal proprioceptive evocation and the presence of a hydraulic mechanism that may require ophthalmic examination. PMID:23814636

Short-term effects of oil ingestion on American kestrels (Falco sparverius).

PubMed

Pattee, O H; Franson, J C

1982-04-01

The Mexican Ixtoc oil well blowout resulted in extensive oil contamination along the Texas Gulf coast. This oil posed a potential hazard to migrating birds including the endangered peregrine falcon (Falco peregrinus). Laboratory tests with the American kestrel (Falco sparverius) indicated that the oil: water mixture gathered at the surface of the blowout site posed little acute hazard to falcons.

30 CFR 250.1707 - What are the requirements for blowout preventer system testing, records, and drills?

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 blowout preventer system testing, records, and drills? 250.1707 Section 250.1707 Mineral Resources BUREAU OF SAFETY AND..., you must conduct a low-pressure test and a high-pressure test for each component. You must conduct the...

30 CFR 250.1707 - What are the requirements for blowout preventer system testing, records, and drills?

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 blowout preventer system testing, records, and drills? 250.1707 Section 250.1707 Mineral Resources BUREAU OF SAFETY AND..., you must conduct a low-pressure test and a high-pressure test for each component. You must conduct the...

Prediction and validation of blowout limits of co-flowing jet diffusion flames -- effect of dilution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karbasi, M.; Wierzba, I.

1996-10-01

The blowout limits of a co-flowing turbulent methane jet diffusion flame with addition of diluent in either jet fuel or surrounding air stream is studied both analytically and experimentally. Helium, nitrogen and carbon dioxide were employed as the diluents. Experiments indicated that an addition of diluents to the jet fuel or surrounding air stream decreased the stability limit of the jet diffusion flames. The strongest effect was observed with carbon dioxide as the diluent followed by nitrogen and then by helium. A model of extinction based on recognized criterion of the mixing time scale to characteristic combustion time scale ratiomore » using experimentally derived correlations is proposed. It is capable of predicting the large reduction of the jet blowout velocity due to a relatively small increase in the co-flow stream velocity along with an increase in the concentration of diluent in either the jet fuel or surrounding air stream. Experiments were carried out to validate the model. The predicted blowout velocities of turbulent jet diffusion flames obtained using this model are in good agreement with the corresponding experimental data.« less

Blowout brought under control in Gulf of Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1992-10-19

This paper reports that Greenhill Petroleum Corp., Houston, killed a well blowout Oct. 9 and began cleaning up oil spilled into Timbalier Bay off La Fourche Parish, La. Development well No. 250 in Timbalier Bay field blew out Sept. 29 while Blake Drilling and Workover Co., Belle Chasse, La., was trying to recomplete it in a deeper zone. Fire broke out as Boots and Coots Inc., Houston, was positioning control equipment at the wellhead. State and federal oil spill response officials estimated the uncontrolled flow of well No. 250 at 1,400 b/d of oil. Coast Guard officials on Oct. 8more » upgraded the blowout to a major spill, after deciding that at least 2,500 bbl of oil had gone into the water.« less

Independent Technical Investigation of the Puna Geothermal Venture Unplanned Steam Release, June 12 and 13, 1991, Puna, Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Richard; Whiting, Dick; Moore, James

1991-07-01

On June 24, 1991, a third-party investigation team consisting of Richard P. Thomas, Duey E. Milner, James L. Moore, and Dick Whiting began an investigation into the blowout of well KS-8, which occurred at the Puna Geothermal Venture (PGV) site on June 12, 1991, and caused the unabated release of steam for a period of 31 hours before PGV succeeded in closing in the well. The scope of the investigation was to: (a) determine the cause(s) of the incident; (b) evaluate the adequacy of PGVs drilling and blowout prevention equipment and procedures; and (c) make recommendations for any appropriate changesmore » in equipment and/or procedures. This report finds that the blowout occurred because of inadequacies in PGVs drilling plan and procedures and not as a result of unusual or unmanageable subsurface geologic or hydrologic conditions. While the geothermal resource in the area being drilled is relatively hot, the temperatures are not excessive for modem technology and methods to control. Fluid pressures encountered are also manageable if proper procedures are followed and the appropriate equipment is utilized. A previous blowout of short duration occurred on February 21, 1991, at the KS-7 injection well being drilled by PGV at a depth of approximately 1600'. This unexpected incident alerted PGV to the possibility of encountering a high temperature, fractured zone at a relatively shallow depth. The experience at KS-7 prompted PGV to refine its hydrological model; however, the drilling plan utilized for KS-8 was not changed. Not only did PGV fail to modify its drilling program following the KS-7 blowout, but they also failed to heed numerous ''red flags'' (warning signals) in the five days preceding the KS-8 blowout, which included a continuous 1-inch flow of drilling mud out of the wellbore, gains in mud volume while pulling stands, and gas entries while circulating muds bottoms up, in addition to lost circulation that had occurred earlier below the shoe of the 13-3/8-hch casing.« less

Modeling the key factors that could influence the diffusion of CO2 from a wellbore blowout in the Ordos Basin, China.

PubMed

Li, Qi; Shi, Hui; Yang, Duoxing; Wei, Xiaochen

2017-02-01

Carbon dioxide (CO 2 ) blowout from a wellbore is regarded as a potential environment risk of a CO 2 capture and storage (CCS) project. In this paper, an assumed blowout of a wellbore was examined for China's Shenhua CCS demonstration project. The significant factors that influenced the diffusion of CO 2 were identified by using a response surface method with the Box-Behnken experiment design. The numerical simulations showed that the mass emission rate of CO 2 from the source and the ambient wind speed have significant influence on the area of interest (the area of high CO 2 concentration above 30,000 ppm). There is a strong positive correlation between the mass emission rate and the area of interest, but there is a strong negative correlation between the ambient wind speed and the area of interest. Several other variables have very little influence on the area of interest, e.g., the temperature of CO 2 , ambient temperature, relative humidity, and stability class values. Due to the weather conditions at the Shenhua CCS demonstration site at the time of the modeled CO 2 blowout, the largest diffusion distance of CO 2 in the downwind direction did not exceed 200 m along the centerline. When the ambient wind speed is in the range of 0.1-2.0 m/s and the mass emission rate is in the range of 60-120 kg/s, the range of the diffusion of CO 2 is at the most dangerous level (i.e., almost all Grade Four marks in the risk matrix). Therefore, if the injection of CO 2 takes place in a region that has relatively low perennial wind speed, special attention should be paid to the formulation of pre-planned, emergency measures in case there is a leakage accident. The proposed risk matrix that classifies and grades blowout risks can be used as a reference for the development of appropriate regulations. This work may offer some indicators in developing risk profiles and emergency responses for CO 2 blowouts.

Impact of an historic underground gas well blowout on the current methane chemistry in a shallow groundwater system

PubMed Central

Schout, Gilian; Hartog, Niels; Hassanizadeh, S. Majid; Griffioen, Jasper

2018-01-01

Blowouts present a small but genuine risk when drilling into the deep subsurface and can have an immediate and significant impact on the surrounding environment. Nevertheless, studies that document their long-term impact are scarce. In 1965, a catastrophic underground blowout occurred during the drilling of a gas well in The Netherlands, which led to the uncontrolled release of large amounts of natural gas from the reservoir to the surface. In this study, the remaining impact on methane chemistry in the overlying aquifers was investigated. Methane concentrations higher than 10 mg/L (n = 12) were all found to have δ13C-CH4 values larger than −30‰, typical of a thermogenic origin. Both δ13C-CH4 and δD-CH4 correspond to the isotopic composition of the gas reservoir. Based on analysis of local groundwater flow conditions, this methane is not a remnant but most likely the result of ongoing leakage from the reservoir as a result of the blowout. Progressive enrichment of both δ13C-CH4 and δD-CH4 is observed with increasing distance and decreasing methane concentrations. The calculated isotopic fractionation factors of εC = 3 and εD = 54 suggest anaerobic methane oxidation is partly responsible for the observed decrease in concentrations. Elevated dissolved iron and manganese concentrations at the fringe of the methane plume show that oxidation is primarily mediated by the reduction of iron and manganese oxides. Combined, the data reveal the long-term impact that underground gas well blowouts may have on groundwater chemistry, as well as the important role of anaerobic oxidation in controlling the fate of dissolved methane. PMID:29279383

A novel integrated approach for path following and directional stability control of road vehicles after a tire blow-out

NASA Astrophysics Data System (ADS)

Wang, Fei; Chen, Hong; Guo, Konghui; Cao, Dongpu

2017-09-01

The path following and directional stability are two crucial problems when a road vehicle experiences a tire blow-out or sudden tire failure. Considering the requirement of rapid road vehicle motion control during a tire blow-out, this article proposes a novel linearized decoupling control procedure with three design steps for a class of second order multi-input-multi-output non-affine system. The evaluating indicators for controller performance are presented and a performance related control parameter distribution map is obtained based on the stochastic algorithm which is an innovation for non-blind parameter adjustment in engineering implementation. The analysis on the robustness of the proposed integrated controller is also performed. The simulation studies for a range of driving conditions are conducted, to demonstrate the effectiveness of the proposed controller.

Bunch modulation in LWFA blowout regime

NASA Astrophysics Data System (ADS)

Vyskočil, Jiří; Klimo, Ondřej; Vieira, Jorge; Korn, Georg

2015-05-01

Laser wakefield acceleration (LWFA) is able to produce high quality electron bunches interesting for many applications ranging from coherent light sources to high energy physics. The blow-out regime of LWFA provides excellent accelerating structure able to maintain small transverse emittance and energy spread of the accelerating electron beam if combined with localised injection. A modulation of the back of a self-injected electron bunch in the blowout regime of Laser Wakefield Acceleration appears 3D Particle-in-Cell simulations with the code OSIRIS. The shape of the modulation is connected to the polarization of the driving laser pulse, although the wavelength of the modulation is longer than that of the pulse. Nevertheless a circularly polarized laser pulse leads to a corkscrew-like modulation, while in the case of linear polarization, the modulation lies in the polarization plane.

Betatron x-ray radiation from laser-plasma accelerators driven by femtosecond and picosecond laser systems

NASA Astrophysics Data System (ADS)

Albert, F.; Lemos, N.; Shaw, J. L.; King, P. M.; Pollock, B. B.; Goyon, C.; Schumaker, W.; Saunders, A. M.; Marsh, K. A.; Pak, A.; Ralph, J. E.; Martins, J. L.; Amorim, L. D.; Falcone, R. W.; Glenzer, S. H.; Moody, J. D.; Joshi, C.

2018-05-01

A comparative experimental study of betatron x-ray radiation from laser wakefield acceleration in the blowout and self-modulated regimes is presented. Our experiments use picosecond duration laser pulses up to 150 J (self-modulated regime) and 60 fs duration laser pulses up to 10 J (blowout regime), for plasmas with electronic densities on the order of 1019 cm-3. In the self-modulated regime, where betatron radiation has been very little studied compared to the blowout regime, electrons accelerated in the wake of the laser pulse are subject to both the longitudinal plasma and transverse laser electrical fields. As a result, their motion within the wake is relatively complex; consequently, the experimental and theoretical properties of the x-ray source based on self-modulation differ from the blowout regime of laser wakefield acceleration. In our experimental configuration, electrons accelerated up to about 250 MeV and betatron x-ray spectra with critical energies of about 10-20 keV and photon fluxes between 108 and 1010 photons/eV Sr are reported. Our experiments open the prospect of using betatron x-ray radiation for applications, and the source is competitive with current x-ray backlighting methods on multi-kilojoule laser systems.

Seed bank dynamics of blowout penstemon in relation to local patterns of sand movement on the Ferris Dunes, south-central Wyoming

Treesearch

Kassie L. Tilini; Susan E. Meyer; Phil S. Allen

2017-01-01

Plants restricted to active sand dunes possess traits that enable both survival in a harsh environment and local migration in response to a shifting habitat mosaic. We examined seed bank dynamics of Penstemon haydenii S. Watson (blowout penstemon) in relation to local sand movement. We measured within-year sand movement along a 400 m transect and examined plant density...

Breaking primary seed dormancy in Gibbens' beardtongue (Penstemon gibbensii) and blowout penstemon (Penstemon haydenii)

Treesearch

Kassie L. Tilini; Susan E. Meyer; Phil S. Allen

2016-01-01

This study established that chilling removes primary seed dormancy in 2 rare penstemons of the western US, Gibbens’ beardtongue (Penstemon gibbensii Dorn [Scrophulariaceae]) and blowout penstemon (Penstemon haydenii S. Watson). Wild-harvested seeds were subjected either to moist chilling at 2 to 4 °C (36-39 °F) for 0, 4, 8, 12, and 16 wk or to approximately 2 y of dry...

Real Time Navigation-Assisted Orbital Wall Reconstruction in Blowout Fractures.

PubMed

Shin, Ho Seong; Kim, Se Young; Cha, Han Gyu; Han, Ba Leun; Nam, Seung Min

2016-03-01

Limitation in performing restoration of orbital structures is the narrow, deep, and dark surgical field, which makes it difficult to view the operative site directly. To avoid perioperative complications from this limitation, the authors have evaluated the usefulness of computer-assisted navigation techniques in surgical treatment of blowout fracture. Total 37 patients (14 medial orbital wall fractures and 23 inferior orbital wall fractures) with facial deformities had surgical treatment under the guide of navigation system between September 2012 and January 2015. All 37 patients were treated successfully and safely with navigation-assisted surgery without any complications, including diplopia, retrobulbar hematoma, globe injury, implant migration, and blindness. Blowout fracture can be treated safely under guidance of a surgical navigation system. In orbital surgery, navigation-assisted technology could give rise to improvements in the functional and aesthetic outcome and checking the position of the instruments on the surgical site in real time, without injuring important anatomic structures.

Dynamic Blowout Risk Analysis Using Loss Functions.

PubMed

Abimbola, Majeed; Khan, Faisal

2018-02-01

Most risk analysis approaches are static; failing to capture evolving conditions. Blowout, the most feared accident during a drilling operation, is a complex and dynamic event. The traditional risk analysis methods are useful in the early design stage of drilling operation while falling short during evolving operational decision making. A new dynamic risk analysis approach is presented to capture evolving situations through dynamic probability and consequence models. The dynamic consequence models, the focus of this study, are developed in terms of loss functions. These models are subsequently integrated with the probability to estimate operational risk, providing a real-time risk analysis. The real-time evolving situation is considered dependent on the changing bottom-hole pressure as drilling progresses. The application of the methodology and models are demonstrated with a case study of an offshore drilling operation evolving to a blowout. © 2017 Society for Risk Analysis.

Development of a unified oil droplet size distribution model with application to surface breaking waves and subsea blowout releases considering dispersant effects.

PubMed

Li, Zhengkai; Spaulding, Malcolm; French McCay, Deborah; Crowley, Deborah; Payne, James R

2017-01-15

An oil droplet size model was developed for a variety of turbulent conditions based on non-dimensional analysis of disruptive and restorative forces, which is applicable to oil droplet formation under both surface breaking-wave and subsurface-blowout conditions, with or without dispersant application. This new model was calibrated and successfully validated with droplet size data obtained from controlled laboratory studies of dispersant-treated and non-treated oil in subsea dispersant tank tests and field surveys, including the Deep Spill experimental release and the Deepwater Horizon blowout oil spill. This model is an advancement over prior models, as it explicitly addresses the effects of the dispersed phase viscosity, resulting from dispersant application and constrains the maximum stable droplet size based on Rayleigh-Taylor instability that is invoked for a release from a large aperture. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative Risk Assessment (QRA) for an Underground Blowout Scenario in the Gulf of Mexico (GoM) Well

NASA Astrophysics Data System (ADS)

Tyagi, M.; Zulqarnain, M.

2017-12-01

Offshore oil and gas exploration and production operations, involve the use of some of the cutting edge and challenging technologies of the modern time. These technological complex operations involves the risk of major accidents as well, which have been demonstrated by disasters such as the explosion and fire on the UK production platform piper alpha, the Canadian semi-submersible drilling rig Ocean Ranger and the explosion and capsizing of Deepwater horizon rig in the Gulf of Mexico. By conducting Quantitative Risk Assessment (QRA), safety of various operations as well as their associated risks and significance during the entire life phase of an offshore project can be quantitatively estimated. In an underground blowout, the uncontrolled formation fluids from higher pressure formation may charge up shallower overlying low pressure formations or may migrate to sea floor. Consequences of such underground blowouts range from no visible damage at the surface to the complete loss of well, loss of drilling rig, seafloor subsidence or hydrocarbons discharged to the environment. These blowouts might go unnoticed until the over pressured sands, which are the result of charging from higher pressure reservoir due to an underground blowout. Further, engineering formulas used to estimate the fault permeability and thickness are very simple in nature and may add to uncertainty in the estimated parameters. In this study the potential of a deepwater underground blowout are assessed during drilling life phase of a well in Popeye-Genesis field reservoir in the Gulf of Mexico to estimate the time taken to charge a shallower zone to its leak-off test (LOT) value. Parametric simulation results for selected field case show that for relatively high permeability (k = 40mD) fault connecting a deep over-pressured zone to a shallower low-pressure zone of similar reservoir volumes, the time to recharge the shallower zone up to its threshold LOT value is about 135 years. If the ratio of the reservoir volumes for shallower to deeper zone is about 0.1, the recharging time significantly decreased to 24 years. Also, the hydrocarbons might possibly migrate through casing-wellbore annulus due to delamination fractures between cement interfaces with rock/casing and any other micro annulus gap not isolated by cement.

An experimental study of flame stability in a directly-fueled wall cavity with a supersonic free stream

NASA Astrophysics Data System (ADS)

Rasmussen, Chadwick Clifford

An extensive study of flame stability in a cavity-based fuel injector/flameholder has been performed. Flames were stabilized in cavities with two different aft wall configurations and length to depth ratios of 3 and 4. Fuel was injected directly into the cavity using two injector configurations. Fuel injected from the aft wall of the cavity entered directly into the recirculation zone and provided desirable performance near the lean blowout limit. At high fuel flowrates, the cavity became flooded with fuel and rich blowout occurred. When fuel was injected from the floor of the cavity, excess fuel was directed out of the cavity which allowed for flame stabilization at extremely high fuel flowrates; however, this phenomenon also resulted in suboptimal performance near the lean limit where the blowout point was less predictable. Images of planar laser-induced fluorescence (PLIF) of CH, OH, and formaldehyde give insight into the flameholding mechanisms. CH layers in the cavity are thin and continuous and show structure that is comparable to lifted jet flames, while broad CH zones are sometimes observed in the shear layer. OH PLIF images show that hot recirculated products are always present at the location of flame stabilization, whereas images of formaldehyde indicate that partial premixing takes place in the shear layer portion of the flame. Nonreacting measurements of the boundary layer and the free stream velocity profiles were obtained to provide necessary boundary conditions for computational modeling. Mean and instantaneous velocity profiles were determined for the nonreacting flow using particle image velocimetry (PIV). A correlation of the blowout points for a directly-fueled cavity in a supersonic flow was accomplished using a Damkohler number and an equivalence ratio based upon an effective air mass flowrate. The chemical time was formulated using a generic measure of the reaction rate, tauc ˜ alpha/ S2L , which was found to be adequate for correlating lean blowout data from methane, ethylene, acetylene, and hydrogen flames. Blowout data was collected at a number of conditions with varied pressure and temperature and Mach numbers of 2, 2.4, and 3. The effective air mass flowrate was determined using scaling laws for compressible mixing layers, which correctly incorporated the impact of compressibility on air entrainment.

Environmental legacy of an underground gas well blowout: long-term effects of gas and brine leakage on groundwater quality

NASA Astrophysics Data System (ADS)

Schout, Gilian; Hartog, Niels; Majid Hassanizadeh, S.; Griffioen, Jasper

2017-04-01

In 1965, a catastrophic underground blowout occurred during the drilling of a gas well in the village of Sleen, the Netherlands. The blowout led to the uncontrolled release of large amounts of natural gas and saline groundwater. Now, 50 years later, a number of nearby groundwater monitoring have been sampled to study the long term effects of this event on the groundwater composition of the overlying freshwater aquifers. The findings are used as an analogue for studying the potential adverse effects of hydraulic fracturing on groundwater quality. In total, 27 samples were taken and analysed for dissolved gas molecular and isotopic composition, major ion chemistry, water isotopes and stable chlorine isotope ratios. The resulting data show that concentrations of dissolved methane are still strongly elevated compared to background samples in a plume downstream of the blowout location. Isotopic data reveals the thermogenic nature of this plume; all samples with methane concentrations greater than 10 mg/l (n=12) had δC-CH4 values greater than -30‰ (VPDB), characteristic of thermogenic methane. The maximum distance at which thermogenic methane is observed is at approximately 500 meter downstream of the centre of the blowout. The progressive enrichment of both δ13C-CH4 and δ2D-CH4, that is observed with distance from the well and decreasing methane concentrations, presents strong evidence for the role of anaerobic methane oxidation (AOM) in limiting the spread of the dissolved methane plume. Low sulphate and increased Fe(II) and Mn(II) concentrations indeed suggest that multiple AOM pathways are involved in the natural attenuation of the dissolved methane plume. Chlorine concentrations were only elevated in a subset of wells in close proximity to the blowout location, indicating that the present-day effects of brine migration are minimal. Nevertheless, elevated Na/Cl ratio's in multiple wells reveal that freshening of the aquifer is still on-going. In summary, this research sheds new light on the long-term effects of natural gas and brine leakage on groundwater quality, which is considered one of the main environmental hazards related to hydraulic fracturing and unconventional gas production in general. Notably, it shows that the anaerobic oxidation of methane may play a major role in containing the effects of uncontrolled gas migration from reservoirs to shallow aquifers.

Advances in Turbulent Combustion Dynamics Simulations in Bluff-Body Stabilized Flames-Body Stabilized Flames

DTIC Science & Technology

2015-11-30

Master’s Thesis 3. DATES COVERED (From - To) 01 Nov 2015 – 30 Nov 2015 4. TITLE AND SUBTITLE Advances in Turbulent Combustion Dynamics Simulations...the three main aspects of bluff-body stabilized flames: stationary combustion , lean blow-out, and thermo-acoustic instabilities. For the cases of...stationary combustion and lean blow-out, an improved version of the Linear Eddy Model approach is used, while in the case of thermo-acoustic

More Macrospicule Jets in On-Disk Coronal Holes

NASA Astrophysics Data System (ADS)

Adams, Mitzi; Sterling, Alphonse; Moore, Ronald

2015-04-01

We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or at disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of about ten jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 Å, examine the magnetic field configuration and flux changes in the jet area, and discuss the probable trigger mechanism of these events. We reported on another jet in this same coronal hole on 2011 February 27, ~13:04 UT (Adams et al 2014, ApJ, 783: 11). That jet is a previously unrecognized variety of blowout jet, in which the base-edge bright point is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field. In contrast, in the presently-accepted "standard" picture for blowout jets, the base-edge bright point is made by interchange reconnection of initially-closed erupting jet-base field with ambient open field. This poster presents further evidence of the production of the base-edge bright point in blowout jets by internal reconnection. Our observations suggest that most of the bigger and brighter EUV jets in coronal holes are blowout jets of the new-found variety.

Dichotomy of X-Ray Jets in Solar Coronal Holes

NASA Astrophysics Data System (ADS)

Robe, D. M.; Moore, R. L.; Falconer, D. A.

2012-12-01

It has been found that there are two different types of X-ray jets observed in the Sun's polar coronal holes: standard jets and blowout jets. A proposed model of this dichotomy is that a standard jet is produced by a burst of reconnection of the ambient magnetic field with the opposite-polarity leg of the base arcade. In contrast, it appears that a blowout jet is produced when the interior of the arcade has so much pent-up free magnetic energy in the form of shear and twist in the interior field that the external reconnection unleashes the interior field to erupt open. In this project, X-ray movies of the polar coronal holes taken by Hinode were searched for X-ray jets. Co-temporal movies taken by the Solar Dynamics Observatory in 304 Å emission from He II, showing solar plasma at temperatures around 80,000 K, were examined for whether the identified blowout jets carry much more He II plasma than the identified standard jets. It was found that though some jets identified as standard from the X-ray movies could be seen in the He II 304 Å movies, the blowout jets carried much more 80,000 K plasma than did most standard jets. This finding supports the proposed model for the morphology and development of the two types of jets.

Electron self-injection due to a plasma density downramp and gas ionization in a plasma wakefield accelerator in the blowout regime

NASA Astrophysics Data System (ADS)

Yi, S. A.; D'Avignon, E. C.; Khudik, V.; Shvets, G.

2010-11-01

We study self-injection into a plasma wakefield accelerator (PWFA) in the blowout regime analytically and through particle-in-cell (PIC) simulations. We propose a new injection mechanism into a plasma wakefield accelerator, where growth of the blowout region is enabled through a slow decrease in background plasma density along the direction of propagation. Deepening of the potential well due to this growth causes a reduction of electron Hamiltonian in the co-moving frame. This reduction depends on the shape of the blowout region, its growth rate, and impact parameter of the electron. When the reduction is greater than mc^2 [1,2], the electron becomes trapped inside the bubble. We demonstrate this effect using analytic expressions for the bubble potentials [3], and estimate plasma density gradients, and beam charge and size required for injection. We also apply the injection criterion to electron trapping through gas ionization. This work is supported by the US DOE grants DE-FG02-04ER41321 and DE-FG02-07ER54945. [1] S. Kalmykov, S.A. Yi, V. Khudik, and G. Shvets, Phys. Rev. Lett. 103, 135004 (2009). [2] S.A. Yi, V. Khudik, S. Kalmykov, and G. Shvets, Plasma Phys. Contr. Fus., in press. [3] W. Lu, C. Huang, M. Zhou, M. Tzoufras et al., Phys. Plasmas 13, 056709 (2006).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Porse, Sean L.; Wade, Sarah; Hovorka, Susan D.

Risk communication literature suggests that for a number of reasons, the public may perceive a risk to be greater than indicated by its statistical probability. Public concern over risk can lead to significant and costly delays in project permitting and operations. Considering these theories, media coverage of CO₂-related well blowouts in 2013 gave rise to the questions: What is the risk of CO₂ well blowouts associated with CCUS through CO₂ EOR? What is the potential public perception of those risks? What information could be used to respond to public concern? To address these questions, this study aims to: 1) providemore » a framework for understanding the nature of onshore well blowouts, 2) quantify the incidence of such events for three specific geographic regions of Texas, 3) relate this data to CCUS and findings from other studies, and 4) explore the potential implications for public perception of this risk associated with CCUS projects. While quantifying answers to these questions proved to be challenging, the results from this study suggest that (1) the perceived risk of CO₂ well blowouts may exceed the statistical risk and (2) information that could be used to address this gap could be made more readily available to the greater benefit of industry and stakeholders who support the development of CCUS as an option for addressing anthropogenic CO₂ emissions. The study also suggests approaches to best conduct such data inquiries.« less

More Macrospicule Jets in On-Disk Coronal Holes

NASA Technical Reports Server (NTRS)

Adams, M. L.; Sterling, A. C.; Moore, R. L.

2015-01-01

We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or on disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of about ten jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 A, examine the magnetic field configuration and flux changes in the jet area, and discuss the probable trigger mechanism of these events. We reported on another jet in this same coronal hole on 2011 February 27, (is) approximately 13:04 UT (Adams et al 2014, ApJ, 783: 11). That jet is a previously-unrecognized variety of blowout jet, in which the base-edge bright point is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field. In contrast, in the presently-accepted 'standard' picture for blowout jets, the base-edge bright point is made by interchange reconnection of initially-closed erupting jet-base field with ambient open field. This poster presents further evidence of the production of the base-edge bright point in blowout jets by internal reconnection. Our observations suggest that most of the bigger and brighter EUV jets in coronal holes are blowout jets of the new-found variety.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hammeschlag, S.B.; Hughes, S.; O'Reilly, G.V.

Orbital blow-out fractures were experimentally created in eight human cadavers. Each orbit underwent conventional radiographic studies, complex motion tomography, and computed tomographic examinations. A comparison of the three modalities was made. Anatomical correlation was obtained by dissecting the orbits. The significance of medial-wall fractures and enophthalmos is discussed. Limitation of inferior rectus muscle mobility is thought to be a result of muscle kinking associated with orbital fat-pad prolapse at the fracture site, rather than muscle incarceration. Blow-out fractures should be evaluated by computed tomographic computer reformations in the oblique sagittal plane.

Simulating pathways of subsurface oil in the Faroe-Shetland Channel using an ocean general circulation model.

PubMed

Main, C E; Yool, A; Holliday, N P; Popova, E E; Jones, D O B; Ruhl, H A

2017-01-15

Little is known about the fate of subsurface hydrocarbon plumes from deep-sea oil well blowouts and their effects on processes and communities. As deepwater drilling expands in the Faroe-Shetland Channel (FSC), oil well blowouts are a possibility, and the unusual ocean circulation of this region presents challenges to understanding possible subsurface oil pathways in the event of a spill. Here, an ocean general circulation model was used with a particle tracking algorithm to assess temporal variability of the oil-plume distribution from a deep-sea oil well blowout in the FSC. The drift of particles was first tracked for one year following release. Then, ambient model temperatures were used to simulate temperature-mediated biodegradation, truncating the trajectories of particles accordingly. Release depth of the modeled subsurface plumes affected both their direction of transport and distance travelled from their release location, and there was considerable interannual variability in transport. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Behavior and dynamics of bubble breakup in gas pipeline leaks and accidental subsea oil well blowouts.

PubMed

Wang, Binbin; Socolofsky, Scott A; Lai, Chris C K; Adams, E Eric; Boufadel, Michel C

2018-06-01

Subsea oil well blowouts and pipeline leaks release oil and gas to the environment through vigorous jets. Predicting the breakup of the released fluids in oil droplets and gas bubbles is critical to predict the fate of petroleum compounds in the marine water column. To predict the gas bubble size in oil well blowouts and pipeline leaks, we observed and quantified the flow behavior and breakup process of gas for a wide range of orifice diameters and flow rates. Flow behavior at the orifice transitions from pulsing flow to continuous discharge as the jet crosses the sonic point. Breakup dynamics transition from laminar to turbulent at a critical value of the Weber number. Very strong pure gas jets and most gas/liquid co-flowing jets exhibit atomization breakup. Bubble sizes in the atomization regime scale with the jet-to-plume transition length scale and follow -3/5 power-law scaling for a mixture Weber number. Copyright © 2018 Elsevier Ltd. All rights reserved.

Minifilament Eruption as the Source of a Blowout Jet, C-class Flare, and Type-III Radio Burst

NASA Astrophysics Data System (ADS)

Hong, Junchao; Jiang, Yunchun; Yang, Jiayan; Li, Haidong; Xu, Zhe

2017-01-01

We report a strong minifilament eruption associated with Geostationary Operational Environmental Satellite C1.6 flare and WIND type-III radio burst. The minifilament, which lies at the periphery of active region 12259, is detected by Hα images from the New Vacuum Solar Telescope. The minifilament undergoes a partial and then a full eruption. Simultaneously, two co-spatial jets are successively observed in extreme ultraviolet images from the Solar Dynamic Observatory. The first jet exhibits a typical fan-spine geometry, suggesting that the co-spatial minifilament is possibly embedded in magnetic fields with a fan-spine structure. However, the second jet displays blowout morphology when the entire minifilament erupts upward, leaving behind a hard X-ray emission source in the base. Differential emission measure analyses show that the eruptive region is heated up to about 4 MK during the fan-spine jet, while up to about 7 MK during the blowout jet. In particular, the blowout jet is accompanied by an interplanetary type-III radio burst observed by WIND/WAVES in the frequency range from above 10 to 0.1 MHz. Hence, the minifilament eruption is correlated with the interplanetary type-III radio burst for the first time. These results not only suggest that coronal jets can result from magnetic reconnection initiated by erupting minifilaments with open fields, but also shed light on the potential influence of minifilament eruption on interplanetary space.

The Measurement of the Sensory Recovery Period in Zygoma and Blow-Out Fractures with Neurometer Current Perception Threshold.

PubMed

Oh, Daemyung; Yun, Taebin; Kim, Junhyung; Choi, Jaehoon; Jeong, Woonhyeok; Chu, Hojun; Lee, Soyoung

2016-09-01

Facial hypoesthesia is one of the most troublesome complaints in the management of facial bone fractures. However, there is a lack of literature on facial sensory recovery after facial trauma. The purpose of this study was to evaluate the facial sensory recovery period for facial bone fractures using Neurometer. Sixty-three patients who underwent open reduction of zygomatic and blowout fractures between December 2013 and July 2015 were included in the study. The facial sensory status of the patients was repeatedly examined preoperatively and postoperatively by Neurometer current perception threshold (CPT) until the results were normalized. Among the 63 subjects, 30 patients had normal Neurometer results preoperatively and postoperatively. According to fracture types, 17 patients with blowout fracture had a median recovery period of 0.25 months. Twelve patients with zygomatic fracture had a median recovery period of 1.00 month. Four patients with both fracture types had a median recovery period of 0.625 months. The median recovery period of all 33 patients was 0.25 months. There was no statistically significant difference in the sensory recovery period between types and subgroups of zygomatic and blowout fractures. In addition, there was no statistically significant difference in the sensory recovery period according to Neurometer results and the patients' own subjective reports. Neurometer CPT is effective for evaluating and comparing preoperative and postoperative facial sensory status and evaluating the sensory recovery period in facial bone fracture patients.

MINIFILAMENT ERUPTION AS THE SOURCE OF A BLOWOUT JET, C-CLASS FLARE, AND TYPE-III RADIO BURST

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Junchao; Jiang, Yunchun; Yang, Jiayan

We report a strong minifilament eruption associated with Geostationary Operational Environmental Satellite C1.6 flare and WIND type-III radio burst. The minifilament, which lies at the periphery of active region 12259, is detected by H α images from the New Vacuum Solar Telescope. The minifilament undergoes a partial and then a full eruption. Simultaneously, two co-spatial jets are successively observed in extreme ultraviolet images from the Solar Dynamic Observatory . The first jet exhibits a typical fan-spine geometry, suggesting that the co-spatial minifilament is possibly embedded in magnetic fields with a fan-spine structure. However, the second jet displays blowout morphology whenmore » the entire minifilament erupts upward, leaving behind a hard X-ray emission source in the base. Differential emission measure analyses show that the eruptive region is heated up to about 4 MK during the fan-spine jet, while up to about 7 MK during the blowout jet. In particular, the blowout jet is accompanied by an interplanetary type-III radio burst observed by WIND /WAVES in the frequency range from above 10 to 0.1 MHz. Hence, the minifilament eruption is correlated with the interplanetary type-III radio burst for the first time. These results not only suggest that coronal jets can result from magnetic reconnection initiated by erupting minifilaments with open fields, but also shed light on the potential influence of minifilament eruption on interplanetary space.« less

Computer simulation of reservoir depletion and oil flow from the Macondo well following the Deepwater Horizon blowout

USGS Publications Warehouse

Hsieh, Paul

2010-01-01

This report describes the application of a computer model to simulate reservoir depletion and oil flow from the Macondo well following the Deepwater Horizon blowout. Reservoir and fluid data used for model development are based on (1) information released in BP's investigation report of the incident, (2) information provided by BP personnel during meetings in Houston, Texas, and (3) calibration by history matching to shut-in pressures measured in the capping stack during the Well Integrity Test. The model is able to closely match the measured shut-in pressures. In the simulation of the 86-day period from the blowout to shut in, the simulated reservoir pressure at the well face declines from the initial reservoir pressure of 11,850 pounds per square inch (psi) to 9,400 psi. After shut in, the simulated reservoir pressure recovers to a final value of 10,300 psi. The pressure does not recover back to the initial pressure owing to reservoir depletion caused by 86 days of oil discharge. The simulated oil flow rate declines from 63,600 stock tank barrels per day just after the Deepwater Horizon blowout to 52,600 stock tank barrels per day just prior to shut in. The simulated total volume of oil discharged is 4.92 million stock tank barrels. The overall uncertainty in the simulated flow rates and total volume of oil discharged is estimated to be + or - 10 percent.

The Correlation between the Orbital Volume Ratio and Enophthalmos in Unoperated Blowout Fractures

PubMed Central

Choi, Su Hyun; Gu, Ja Hea

2016-01-01

Background Enophthalmos may not appear immediately after trauma due to periorbital swelling in a blowout fracture, and preoperative measurements of enophthalmos cannot be used as a reliable guideline. It is important to predict the eventual final extent of enophthalmos in order to determine whether to perform surgery, and there have been several attempts to predict the degree of late enophthalmos using preoperative orbital volume. The purpose of this study is to investigate the correlation between the orbital volume ratio (OVR) with final enophthalmos and the palpebral fissure, and to find the OVR that induced 2 mm of enophthalmos in unilateral unoperated blowout fractures. Methods We retrospectively reviewed the medical records of 38 patients and divided them into 3 groups, determined by the fracture location. The relationships between the OVR and both the degree of enophthalmos and the palpebral fissure ratio (PFR) were assessed and, in particular, the OVR that induced 2 mm of enophthalmos was sought. Results Enophthalmos increased in proportion to the OVR, and there was a highly significant correlation between the increase in the OVR and the degree of enophthalmos (P<0.05). On the other hand, there was no correlation between OVR and PFR (P>0.05). The OVR that induced 2-mm enophthalmos was 112.18%. Conclusions The final degree of enophthalmos can be estimated by the preoperative measurement of OVR. Preoperative measurements of OVR can be used as quantitative values to predict the final degree of enophthalmos in pure blowout fractures. PMID:27896181

The Correlation between the Orbital Volume Ratio and Enophthalmos in Unoperated Blowout Fractures.

PubMed

Choi, Su Hyun; Kang, Dong Hee; Gu, Ja Hea

2016-11-01

Enophthalmos may not appear immediately after trauma due to periorbital swelling in a blowout fracture, and preoperative measurements of enophthalmos cannot be used as a reliable guideline. It is important to predict the eventual final extent of enophthalmos in order to determine whether to perform surgery, and there have been several attempts to predict the degree of late enophthalmos using preoperative orbital volume. The purpose of this study is to investigate the correlation between the orbital volume ratio (OVR) with final enophthalmos and the palpebral fissure, and to find the OVR that induced 2 mm of enophthalmos in unilateral unoperated blowout fractures. We retrospectively reviewed the medical records of 38 patients and divided them into 3 groups, determined by the fracture location. The relationships between the OVR and both the degree of enophthalmos and the palpebral fissure ratio (PFR) were assessed and, in particular, the OVR that induced 2 mm of enophthalmos was sought. Enophthalmos increased in proportion to the OVR, and there was a highly significant correlation between the increase in the OVR and the degree of enophthalmos (P<0.05). On the other hand, there was no correlation between OVR and PFR (P>0.05). The OVR that induced 2-mm enophthalmos was 112.18%. The final degree of enophthalmos can be estimated by the preoperative measurement of OVR. Preoperative measurements of OVR can be used as quantitative values to predict the final degree of enophthalmos in pure blowout fractures.

Reliability Analysis of the Electrical Control System of Subsea Blowout Preventers Using Markov Models

PubMed Central

Liu, Zengkai; Liu, Yonghong; Cai, Baoping

2014-01-01

Reliability analysis of the electrical control system of a subsea blowout preventer (BOP) stack is carried out based on Markov method. For the subsea BOP electrical control system used in the current work, the 3-2-1-0 and 3-2-0 input voting schemes are available. The effects of the voting schemes on system performance are evaluated based on Markov models. In addition, the effects of failure rates of the modules and repair time on system reliability indices are also investigated. PMID:25409010

Characterization of complexities in combustion instability in a lean premixed gas-turbine model combustor.

PubMed

Gotoda, Hiroshi; Amano, Masahito; Miyano, Takaya; Ikawa, Takuya; Maki, Koshiro; Tachibana, Shigeru

2012-12-01

We characterize complexities in combustion instability in a lean premixed gas-turbine model combustor by nonlinear time series analysis to evaluate permutation entropy, fractal dimensions, and short-term predictability. The dynamic behavior in combustion instability near lean blowout exhibits a self-affine structure and is ascribed to fractional Brownian motion. It undergoes chaos by the onset of combustion oscillations with slow amplitude modulation. Our results indicate that nonlinear time series analysis is capable of characterizing complexities in combustion instability close to lean blowout.

Blowout jets and impulsive eruptive flares in a bald-patch topology

NASA Astrophysics Data System (ADS)

Chandra, R.; Mandrini, C. H.; Schmieder, B.; Joshi, B.; Cristiani, G. D.; Cremades, H.; Pariat, E.; Nuevo, F. A.; Srivastava, A. K.; Uddin, W.

2017-02-01

Context. A subclass of broad extreme ultraviolet (EUV) and X-ray jets, called blowout jets, have become a topic of research since they could be the link between standard collimated jets and coronal mass ejections (CMEs). Aims: Our aim is to understand the origin of a series of broad jets, some of which are accompanied by flares and associated with narrow and jet-like CMEs. Methods: We analyze observations of a series of recurrent broad jets observed in AR 10484 on 21-24 October 2003. In particular, one of them occurred simultaneously with an M2.4 flare on 23 October at 02:41 UT (SOLA2003-10-23). Both events were observed by the ARIES Hα Solar Tower-Telescope, TRACE, SOHO, and RHESSI instruments. The flare was very impulsive and followed by a narrow CME. A local force-free model of AR 10484 is the basis to compute its topology. We find bald patches (BPs) at the flare site. This BP topology is present for at least two days before to events. Large-scale field lines, associated with the BPs, represent open loops. This is confirmed by a global potential free source surface (PFSS) model. Following the brightest leading edge of the Hα and EUV jet emission, we can temporarily associate these emissions with a narrow CME. Results: Considering their characteristics, the observed broad jets appear to be of the blowout class. As the most plausible scenario, we propose that magnetic reconnection could occur at the BP separatrices forced by the destabilization of a continuously reformed flux rope underlying them. The reconnection process could bring the cool flux-rope material into the reconnected open field lines driving the series of recurrent blowout jets and accompanying CMEs. Conclusions: Based on a model of the coronal field, we compute the AR 10484 topology at the location where flaring and blowout jets occurred from 21 to 24 October 2003. This topology can consistently explain the origin of these events. The movie associated to Fig. 1 is available at http://www.aanda.org

Differences in 1D electron plasma wake field acceleration in MeV versus GeV and linear versus blowout regimes

NASA Astrophysics Data System (ADS)

Tsiklauri, David

2018-03-01

In some laboratory and most astrophysical situations, plasma wake-field acceleration of electrons is one dimensional, i.e., variation transverse to the beam's motion can be ignored. Thus, one dimensional, particle-in-cell (PIC), fully electromagnetic simulations of electron plasma wake field acceleration are conducted in order to study the differences in electron plasma wake field acceleration in MeV versus GeV and linear versus blowout regimes. First, we show that caution needs to be taken when using fluid simulations, as PIC simulations prove that an approximation for an electron bunch not to evolve in time for a few hundred plasma periods only applies when it is sufficiently relativistic. This conclusion is true irrespective of the plasma temperature. We find that in the linear regime and GeV energies, the accelerating electric field generated by the plasma wake is similar to the linear and MeV regimes. However, because GeV energy driving bunch stays intact for a much longer time, the final acceleration energies are much larger in the GeV energies case. In the GeV energy range and blowout regime, the wake's accelerating electric field is much larger in amplitude compared with the linear case and also plasma wake geometrical size is much larger. Thus, the correct positioning of the trailing bunch is needed to achieve the efficient acceleration. For the considered case, optimally, there should be approximately (90-100)c/ωpe distance between the trailing and driving electron bunches in the GeV blowout regime.

Tracking the Hercules 265 marine gas well blowout in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Romero, Isabel C.; Özgökmen, Tamay; Snyder, Susan; Schwing, Patrick; O'Malley, Bryan J.; Beron-Vera, Francisco J.; Olascoaga, Maria J.; Zhu, Ping; Ryan, Edward; Chen, Shuyi S.; Wetzel, Dana L.; Hollander, David; Murawski, Steven A.

2016-01-01

On 23 July 2013, a marine gas rig (Hercules 265) ignited in the northern Gulf of Mexico. The rig burned out of control for 2 days before being extinguished. We conducted a rapid-response sampling campaign near Hercules 265 after the fire to ascertain if sediments and fishes were polluted above earlier baseline levels. A surface drifter study confirmed that surface ocean water flowed to the southeast of the Hercules site, while the atmospheric plume generated by the blowout was in eastward direction. Sediment cores were collected to the SE of the rig at a distance of ˜0.2, 8, and 18 km using a multicorer, and demersal fishes were collected from ˜0.2 to 8 km SE of the rig using a longline (508 hooks). Recently deposited sediments document that only high molecular weight (HMW) polycyclic aromatic hydrocarbon (PAH) concentrations decreased with increasing distance from the rig suggesting higher pyrogenic inputs associated with the blowout. A similar trend was observed in the foraminifera Haynesina germanica, an indicator species of pollution. In red snapper bile, only HMW PAH metabolites increased in 2013 nearly double those from 2012. Both surface sediments and fish bile analyses suggest that, in the aftermath of the blowout, increased concentration of pyrogenically derived hydrocarbons was transported and deposited in the environment. This study further emphasizes the need for an ocean observing system and coordinated rapid-response efforts from an array of scientific disciplines to effectively assess environmental impacts resulting from accidental releases of oil contaminants.

The Gulf of Mexico ecosystem, six years after the Macondo oil well blowout

NASA Astrophysics Data System (ADS)

Joye, Samantha B.; Bracco, Annalisa; Özgökmen, Tamay M.; Chanton, Jeffrey P.; Grosell, Martin; MacDonald, Ian R.; Cordes, Erik E.; Montoya, Joseph P.; Passow, Uta

2016-07-01

The Gulf of Mexico ecosystem is a hotspot for biological diversity and supports a number of industries, from tourism to fishery production to oil and gas exploration, that serve as the economic backbone of Gulf coast states. The Gulf is a natural hydrocarbon basin, rich with stores of oil and gas that lie in reservoirs deep beneath the seafloor. The natural seepage of hydrocarbons across the Gulf system is extensive and, thus, the system's biological components experience ephemeral, if not, frequent, hydrocarbon exposure. In contrast to natural seepage, which is diffuse and variable over space and time, the 2010 Macondo oil well blowout, represented an intense, focused hydrocarbon infusion to the Gulf's deepwaters. The Macondo blowout drove rapid shifts in microbial populations and activity, revealed unexpected phenomena, such as deepwater hydrocarbon plumes and marine "oil snow" sedimentation, and impacted the Gulf's pelagic and benthic ecosystems. Understanding the distribution and fate of Macondo oil was limited to some degree by an insufficient ability to predict the physical movement of water in the Gulf. In other words, the available physical oceanographic models lacked critical components. In the past six years, much has been learned about the physical oceanography of the Gulf, providing transformative knowledge that will improve the ability to predict the movement of water and the hydrocarbons they carry in future blowout scenarios. Similarly, much has been learned about the processing and fate of Macondo hydrocarbons. Here, we provide an overview of the distribution, fate and impacts of Macondo hydrocarbons and offer suggestions for future research to push the field of oil spill response research forward.

Transient flow combustion

NASA Technical Reports Server (NTRS)

Tacina, R. R.

1984-01-01

Non-steady combustion problems can result from engine sources such as accelerations, decelerations, nozzle adjustments, augmentor ignition, and air perturbations into and out of the compressor. Also non-steady combustion can be generated internally from combustion instability or self-induced oscillations. A premixed-prevaporized combustor would be particularly sensitive to flow transients because of its susceptability to flashback-autoignition and blowout. An experimental program, the Transient Flow Combustion Study is in progress to study the effects of air and fuel flow transients on a premixed-prevaporized combustor. Preliminary tests performed at an inlet air temperature of 600 K, a reference velocity of 30 m/s, and a pressure of 700 kPa. The airflow was reduced to 1/3 of its original value in a 40 ms ramp before flashback occurred. Ramping the airflow up has shown that blowout is more sensitive than flashback to flow transients. Blowout occurred with a 25 percent increase in airflow (at a constant fuel-air ratio) in a 20 ms ramp. Combustion resonance was found at some conditions and may be important in determining the effects of flow transients.

Hercules 265 rapid response: Immediate ecosystem impacts of a natural gas blowout incident

NASA Astrophysics Data System (ADS)

Weber, Sarah C.; Peterson, Leigha; Battles, Jessica J.; Roberts, Brian J.; Peterson, Richard N.; Hollander, David J.; Chanton, Jeffrey P.; Joye, Samantha B.; Montoya, Joseph P.

2016-07-01

In late July 2013, the Hercules 265 drilling rig in the Northern Gulf of Mexico experienced a catastrophic loss of control. Large quantities of natural gas spewed into the environment for 2 days before the well self-sealed through down-hole collapse below the seafloor. Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG) and collaborating Gulf of Mexico Research Initiative (GoMRI) consortia mounted a rapid response cruise to characterize the waters around the Hercules 265 rig, beginning just 4 days after the blowout. Our analysis showed an immediate microbial response to the elevated concentrations of methane in the water column, as evidenced by the drawdown of oxygen to hypoxic conditions, the incorporation of methane-derived carbon into particles, and measurable rates of methane-assimilation and nitrogen-fixation. Additionally, radium isotope measurements allowed us to constrain the timescale of bottom water exposure to the influence of the rig. A second sampling by the Center for Integrated Modeling and Analysis of Gulf Ecosystems (C-IMAGE) consortium indicated that the ecosystem had returned to near pre-blowout conditions within one month.

Combustor exhaust-emissions and blowout-limits with diesel number 2 and Jet A fuels utilizing air-atomizing and pressure-atomizing nozzles

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1975-01-01

The effect of fuel properties on exhaust emissions and blowout limits of a high-pressure combustor segment is evaluated using a splash-groove air-atomizing fuel injector and a pressure-atomizing simplex fuel nozzle to burn both diesel number 2 and Jet A fuels. Exhaust emissions and blowout data are obtained and compared on the basis of the aromatic content and volatility of the two fuels. Exhaust smoke number and emission indices for oxides of nitrogen, carbon monoxide, and unburned hydrocarbons are determined for comparison. As compared to the pressure-atomizing nozzle, the air-atomizing nozzle is found to reduce nitrogen oxides by 20%, smoke number by 30%, carbon monoxide by 70%, and unburned hydrocarbons by 50% when used with diesel number 2 fuel. The higher concentration of aromatics and lower volatility of diesel number 2 fuel as compared to Jet A fuel appears to have the most detrimental effect on exhaust emissions. Smoke number and unburned hydrocarbons are twice as high with diesel number 2 as with Jet A fuel.

Sea-floor methane blow-out and global firestorm at the K-T boundary

USGS Publications Warehouse

Max, M.D.; Dillon, William P.; Nishimura, C.; Hurdle, B.G.

1999-01-01

A previously unsuspected source of fuel for the global firestorm recorded by soot in the Cretaceous-Tertiary impact layer may have resided in methane gas associated with gas hydrate in the end-Cretaceous seafloor. End-Cretaceous impact-generated shock and megawaves would have had the potential to initiate worldwide oceanic methane gas blow-outs from these deposits. The methane would likely have ignited and incompletely combusted. This large burst of methane would have been followed by longer-term methane release as a part of a positive thermal feedback in the disturbed ocean-atmosphere system.

The persistence of large-scale blowouts in largely vegetated coastal dune fields

NASA Astrophysics Data System (ADS)

Delgado-Fernandez, Irene; Smyth, Thomas; Jackson, Derek; Davidson-Arnott, Robin; Smith, Alexander

2016-04-01

Coastal dunes move through natural phases of stability and instability during their evolution, displaying various temporal and spatial patterns across the dune field. Recent observations, however, have shown exceptionally rapid rates of stability through increased vegetative growth. This progressive vegetation colonisation and consequent loss of bare sand on coastal dune systems has been noted worldwide. Percentage reductions in bare sand of as much as 80% within just a few decades can been seen in examples from South Africa, Canada and Brazil as well as coastal dune sites across NW Europe. Despite these dramatic trends towards dune stabilisation, it is not uncommon to find particular examples of large-scale active blowouts and parabolic dunes within largely vegetated coastal dunes. While turbulence and airflow dynamics within features such as blowouts and other dune forms has been studied in detail within recent years, there is a lack of knowledge about what maintains dune mobility at these specific points in otherwise largely stabilized dune fields. This work explores the particular example of the 'Devil's Hole' blowout, Sefton Dunes, NW England. Approximately 300 m long by 100 m wide, its basin is below the water-table which leads to frequent flooding. Sefton Dunes in general have seen a dramatic loss of bare sand since the 1940s. However, and coinciding with this period of dune stabilisation, the 'Devil's Hole' has not only remained active but also grown in size at a rate of 4.5 m year-1 along its main axis. An exploration of factors controlling the maintenance of open bare sand areas at this particular location is examined using a variety of techniques including Computational Fluid Dynamics (CFD) airflow modelling and in situ empirical measurements of (short-term experiments) of wind turbulence and sand transport. Field measurements of wind parameters and transport processes were collected over a 2 week period during October 2015. Twenty three 3D ultrasonic anemometers were deployed at 0.5 m elevations over a grid covering sections of the blowout walls, deflation basin and depositional lobe. A number of high resolution sand traps and wenglor sensors were co-located with anemometers in the walls and basin, and a terrestrial laser scanner was used to collect high-resolution topographic data both before and after the strongest transport event recorded during the study period. Preliminary results indicate significant transport differences in operation at each of the two blow out walls as well as complex interactions between turbulence, superficial moisture content and up-wind sediment sources. This study represents a comprehensive examination of both wind and sediment flux patterns at high spatial and temporal resolution inside a large trough blowout feature; and reveals insights into why such systems are maintained as erosional features for long time periods.

Filament Eruptions, Jets, and Space Weather

NASA Technical Reports Server (NTRS)

Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

2013-01-01

Previously, from chromospheric H alpha and coronal X-ray movies of the Sun's polar coronal holes, it was found that nearly all coronal jets (greater than 90%) are one or the other of two roughly equally common different kinds, different in how they erupt: standard jets and blowout jets (Yamauchi et al 2004, Apl, 605, 5ll: Moore et all 2010, Apj, 720, 757). Here, from inspection of SDO/AIA He II 304 A movies of 54 polar x-ray jets observed in Hinode/XRT movies, we report, as Moore et al (2010) anticipated, that (1) most standard x-ray jets (greater than 80%) show no ejected plasma that is cool enough (T is less than or approximately 10(exp 5K) to be seen in the He II 304 A movies; (2) nearly all blownout X-ray jets (greater than 90%) show obvious ejection of such cool plasma; (3) whereas when cool plasma is ejected in standard X-ray jets, it shows no lateral expansion, the cool plasma ejected in blowout X-ray jets shows strong lateral expansion; and (4) in many blowout X-ray jets, the cool plasma ejection displays the erupting-magnetic-rope form of clasic filament eruptions and is thereby seen to be a miniature filament eruption. The XRT movies also showed most blowout X-ray jets to be larger and brighter, and hence to apparently have more energy, than most standard X-ray jets. These observations (1) confirm the dichotomy of coronal jets, (2) agree with the Shibata model for standard jets, and (3) support the conclusion of Moore et al (2010) that in blowout jets the magnetic-arch base of the jet erupts in the manner of the much larger magnetic arcades in which the core field, the field rooted along the arcade's polarity inversion line, is sheared and twisted (sigmoid), often carries a cool-plasma filament, and erupts to blowout the arcade, producing a CME. From Hinode/SOT Ca II movies of the polar limb, Sterling et al (2010, ApJ, 714, L1) found that chromospheric Type-II spicules show a dichotomy of eruption dynamics similar to that found here for the cool-plasma component of coronal X-ray jets. This favors the idea that Type-II spicules are miniature counterparts of coronal X-ray jets. In Moore et al (2011, ApJ, 731, L18), we pointed out that if Type-II spicules are magnetic eruptions that work like coronal X-ray jets, they carry an area-averaged mechanical energy flux of approximately 7x10)(exp 5) erg cm(exp -2) s(exp-1) into the corona in the form of MHD waves and jet outflow, enough to power the heating of the global corona and solar wind. On this basis, from our observations of mini-filament eruptions in blowout X-ray jets, we infer that magnetic explosions of the type that have erupting filaments in them are the main engines of both (1) the steady solar wind and (2) the CMEs that produce the most severe space weather by blasting out through the corona and solar wind, making solar energetic particle storms, and bashing the Earth's magnetosphere. We conclude that in focusing on prominences and filament eruptions, Einar had his eye on the main bet for understanding what powers all space weather, both the extreme and the normal.

Flux rope breaking and formation of a rotating blowout jet

NASA Astrophysics Data System (ADS)

Joshi, Navin Chandra; Nishizuka, Naoto; Filippov, Boris; Magara, Tetsuya; Tlatov, Andrey G.

2018-05-01

We analysed a small flux rope eruption converted into a helical blowout jet in a fan-spine configuration using multiwavelength observations taken by Solar Dynamics Observatory, which occurred near the limb on 2016 January 9. In our study, first, we estimated the fan-spine magnetic configuration with the potential-field calculation and found a sinistral small filament inside it. The filament along with the flux rope erupted upwards and interacted with the surrounding fan-spine magnetic configuration, where the flux rope breaks in the middle section. We observed compact brightening, flare ribbons, and post-flare loops underneath the erupting filament. The northern section of the flux rope reconnected with the surrounding positive polarity, while the southern section straightened. Next, we observed the untwisting motion of the southern leg, which was transformed into a rotating helical blowout jet. The sign of the helicity of the mini-filament matches the one of the rotating jets. This is consistent with recent jet models presented by Adams et al. and Sterling et al. We focused on the fine thread structure of the rotating jet and traced three blobs with the speed of 60-120 km s- 1, while the radial speed of the jet is ˜400 km s- 1. The untwisting motion of the jet accelerated plasma upwards along the collimated outer spine field lines, and it finally evolved into a narrow coronal mass ejection at the height of ˜9Rsun. On the basis of detailed analysis, we discussed clear evidence of the scenario of the breaking of the flux rope and the formation of the helical blowout jet in the fan-spine magnetic configuration.

Determination of the contaminated area after the blowouts in Alasehir (Manisa/Turkey) Geothermal Area using geophysical methods

NASA Astrophysics Data System (ADS)

Timur, Emre

2013-04-01

Western Turkey is one of the most spectacular regions of widespread active continental extension in the world. The most prominent structures of this region are E-W trending Gediz and Büyük Menderes Grabens. Geothermal activity around city of Manisa in Gediz Graben has been investigated by many researchers and many drillings has been opened in order to produce electricity and heating purposes. In the middle of May, 2012, a geothermal blowout occurred 150 m away from the deep drilling, at the depth of 1100 m, in Alkan village of Alasehir resort in city of Manisa. After that, 5 big blowouts happened at the same area and hot water had been diverted to Alkan stream for almost 4 months. In this study, it was intended to determine contaminated area by using magnetic susceptibility measurements for the surface and VLF-R method for underground layers. Magnetic observations were carried out by using Bartington MS2E system and VLF-R by Scintrex ENVI-VLF. It is observed that magnetic susceptibility values vary between 90-160 cgs in the center of the blowout and 30-80 cgs 50 m around of it. All of the susceptibility values were mapped and contaminated areas was clearly defined on the surface using 246 data points. Besides, VLF-R studies were carried out along 21 profiles each of a length of 170 m at three different frequencies with a line and station spacing of 5 m. Laterally constrained two layer inversion was applied to each station and in addition to the inversion of all profiles for each frequency, all lines were stacked within a precise resistivity interval and 2-D maps of the contaminated zones were obtained.

Plasma Wake-field Acceleration in the Blow-out Regime

NASA Astrophysics Data System (ADS)

Barov, Nikolai; Rosenzweig, James

1999-11-01

Recent experiments at Argonne National Laboratory, investigating the blow-out regime of the plasma wake-field accelerator, are discussed. These experiments achieved stable underdense (beam denser than the ambient plasma density) beam transport, and measured average acceleration of 25 MV/m, corresponding to peak wave fields of over 60 MVm. A comparison of the results to simulation is given, and the physics of the system is discussed. Potential for improvements in performance and achieved acceleration gradient, as well as accelerated beam quality are examined within the context of the next generation of experiments at the Fermilab Test Facility. The status of these experiments will be given.

Blowout Monitor

NASA Technical Reports Server (NTRS)

1994-01-01

C Language Integrated Production System (CLIPS), a NASA-developed software shell for developing expert systems, has been embedded in a PC-based expert system for training oil rig personnel in monitoring oil drilling. Oil drilling rigs if not properly maintained for possible blowouts pose hazards to human life, property and the environment may be destroyed. CLIPS is designed to permit the delivery of artificial intelligence on computer. A collection of rules is set up and, as facts become known, these rules are applied. In the Well Site Advisor, CLIPS provides the capability to accurately process, predict and interpret well data in a real time mode. CLIPS was provided to INTEQ by COSMIC.

Credit PSR. The interior of the grinder room appears as ...

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

Credit PSR. The interior of the grinder room appears as seen looking southeast (148°), showing the remaining grinder equipment in the building. Note the blow-out wall in the background, and the water sprinkler head positioned over the hopper. The hopper top is connected to the dust receiver in the adjacent room. The blow-out wall is constructed to relieve pressure easily should an explosion occur, thus minimizing damage to the rest of the building structure. The floor has a conductive coating which dissipates static electrical charges that might otherwise cause fires - Jet Propulsion Laboratory Edwards Facility, Oxidizer Grinder Building, Edwards Air Force Base, Boron, Kern County, CA

Light rare earth element depletion during Deepwater Horizon blowout methanotrophy.

PubMed

Shiller, A M; Chan, E W; Joung, D J; Redmond, M C; Kessler, J D

2017-09-04

Rare earth elements have generally not been thought to have a biological role. However, recent work has demonstrated that the light REEs (LREEs: La, Ce, Pr, and Nd) are essential for at least some methanotrophs, being co-factors in the XoxF type of methanol dehydrogenase (MDH). We show here that dissolved LREEs were significantly removed in a submerged plume of methane-rich water during the Deepwater Horizon (DWH) well blowout. Furthermore, incubation experiments conducted with naturally methane-enriched waters from hydrocarbon seeps in the vicinity of the DWH wellhead also showed LREE removal concurrent with methane consumption. Metagenomic sequencing of incubation samples revealed that LREE-containing MDHs were present. Our field and laboratory observations provide further insight into the biochemical pathways of methanotrophy during the DWH blowout. Additionally, our results are the first observations of direct biological alteration of REE distributions in oceanic systems. In view of the ubiquity of LREE-containing MDHs in oceanic systems, our results suggest that biological uptake of LREEs is an overlooked aspect of the oceanic geochemistry of this group of elements previously thought to be biologically inactive and an unresolved factor in the flux of methane, a potent greenhouse gas, from the ocean.

Blowout Surge due to Interaction between a Solar Filament and Coronal Loops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Haidong; Jiang, Yunchun; Yang, Jiayan

2017-06-20

We present an observation of the interaction between a filament and the outer spine-like loops that produces a blowout surge within one footpoint of large-scale coronal loops on 2015 February 6. Based the observation of the AIA 304 and 94 Å, the activated filament is initially embedded below a dome of a fan-spine configuration. Due to the ascending motion, the erupting filament reconnects with the outer spine-like field. We note that the material in the filament blows out along the outer spine-like field to form the surge with a wider spire, and a two-ribbon flare appears at the site ofmore » the filament eruption. In this process, small bright blobs appear at the interaction region and stream up along the outer spine-like field and down along the eastern fan-like field. As a result, a leg of the filament becomes radial and the material in it erupts, while another leg forms the new closed loops. Our results confirm that the successive reconnection occurring between the erupting filament and the coronal loops may lead to a strong thermal/magnetic pressure imbalance, resulting in a blowout surge.« less

Interaction of hydraulic and buckling mechanisms in blowout fractures.

PubMed

Nagasao, Tomohisa; Miyamoto, Junpei; Jiang, Hua; Tamaki, Tamotsu; Kaneko, Tsuyoshi

2010-04-01

The etiology of blowout fractures is generally attributed to 2 mechanisms--increase in the pressure of the orbital contents (the hydraulic mechanism) and direct transmission of impacts on the orbital walls (the buckling mechanism). The present study aims to elucidate whether or not an interaction exists between these 2 mechanisms. We performed a simulation experiment using 10 Computer-Aided-Design skull models. We applied destructive energy to the orbits of the 10 models in 3 different ways. First, to simulate pure hydraulic mechanism, energy was applied solely on the internal walls of the orbit. Second, to simulate pure buckling mechanism, energy was applied solely on the inferior rim of the orbit. Third, to simulate the combined effect of the hydraulic and buckling mechanisms, energy was applied both on the internal wall of the orbit and inferior rim of the orbit. After applying the energy, we calculated the areas of the regions where fracture occurred in the models. Thereafter, we compared the areas among the 3 energy application patterns. When the hydraulic and buckling mechanisms work simultaneously, fracture occurs on wider areas of the orbital walls than when each of these mechanisms works separately. The hydraulic and buckling mechanisms interact, enhancing each other's effect. This information should be taken into consideration when we examine patients in whom blowout fracture is suspected.

News from the "blowout", a man-made methane pockmark in the North Sea: chemosynthetic communities and microbial methane oxidation

NASA Astrophysics Data System (ADS)

Steinle, Lea I.; Wilfert, Philipp; Schmidt, Mark; Bryant, Lee; Haeckel, Matthias; Lehmann, Moritz F.; Linke, Peter; Sommer, Stefan; Treude, Tina; Niemann, Helge

2013-04-01

The accidental penetration of a base-Quaternary shallow gas pocket by a drilling rig in 1990 caused a "blowout" in the British sector of the North Sea (57°55.29' N, 01°37.86' E). Large quantities of methane have been seeping out of this man-made pockmark ever since. As the onset of gas seepage is well constrained, this site can be used as a natural laboratory to gain information on the development of methane oxidizing microbial communities at cold seeps. During an expedition with the R/V Celtic Explorer in July and August 2012, we collected sediments by video-guided push-coring with an ROV (Kiel 6000) along a gradient from inside the crater (close to where a jet of methane bubbles enters the water column) outwards. We also sampled the water column in a grid above the blowout at three different depths. In this presentation, we provide evidence for the establishment of methanotrophic communities in the sediment (AOM communities) on a time scale of decades. Furthermore, we will report data on methane concentrations and anaerobic methane oxidation rates in the sediment. Finally, we will also discuss the spatial distribution of methane and aerobic methane oxidation rates in the water column.

Lean blowout limits of a gas turbine combustor operated with aviation fuel and methane

NASA Astrophysics Data System (ADS)

Xiao, Wei; Huang, Yong

2016-05-01

Lean blowout (LBO) limits is critical to the operational performance of combustion systems in propulsion and power generation. The swirl cup plays an important role in flame stability and has been widely used in aviation engines. Therefore, the effects of swirl cup geometry and flow dynamics on LBO limits are significant. An experiment was conducted for studying the lean blowout limits of a single dome rectangular model combustor with swirl cups. Three types of swirl cup (dual-axial swirl cup, axial-radial swirl cup, dual-radial swirl cup) were employed in the experiment which was operated with aviation fuel (Jet A-1) and methane under the idle condition. Experimental results showed that, with using both Jet A-1 and methane, the LBO limits increase with the air flow of primary swirler for dual-radial swirl cup, while LBO limits decrease with the air flow of primary swirler for dual-axial swirl cup. In addition, LBO limits increase with the swirl intensity for three swirl cups. The experimental results also showed that the flow dynamics instead of atomization poses a significant influence on LBO limits. An improved semi-empirical correlation of experimental data was derived to predict the LBO limits for gas turbine combustors.

An Anaylsis of Control Requirements and Control Parameters for Direct-Coupled Turbojet Engines

NASA Technical Reports Server (NTRS)

Novik, David; Otto, Edward W.

1947-01-01

Requirements of an automatic engine control, as affected by engine characteristics, have been analyzed for a direct-coupled turbojet engine. Control parameters for various conditions of engine operation are discussed. A hypothetical engine control is presented to illustrate the use of these parameters. An adjustable speed governor was found to offer a desirable method of over-all engine control. The selection of a minimum value of fuel flow was found to offer a means of preventing unstable burner operation during steady-state operation. Until satisfactory high-temperature-measuring devices are developed, air-fuel ratio is considered to be a satisfactory acceleration-control parameter for the attainment of the maximum acceleration rates consistent with safe turbine temperatures. No danger of unstable burner operation exists during acceleration if a temperature-limiting acceleration control is assumed to be effective. Deceleration was found to be accompanied by the possibility of burner blow-out even if a minimum fuel-flow control that prevents burner blow-out during steady-state operation is assumed to be effective. Burner blow-out during deceleration may be eliminated by varying the value of minimum fuel flow as a function of compressor-discharge pressure, but in no case should the fuel flow be allowed to fall below the value required for steady-state burner operation.

Combustor exhaust-emissions and blowout-limits with diesel number 2 and jet A fuels utilizing air-atomizing and pressure atomizing nozzles

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1975-01-01

Experimental tests with diesel number 2 and Jet A fuels were conducted in a combustor segment to obtain comparative data on exhaust emissions and blowout limits. An air-atomizing nozzle was used to inject the fuels. Tests were also made with diesel number 2 fuel using a pressure-atomizing nozzle to determine the effectiveness of the air-atomizing nozzle in reducing exhaust emissions. Test conditions included fuel-air ratios of 0.008 to 0.018, inlet-air total pressures and temperatures of 41 to 203 newtons per square centimeter and 477 to 811 K, respectively, and a reference velocity of 21.3 meters per second. Smoke number and unburned hydrocarbons were twice as high with diesel number 2 as with Jet A fuel. This was attributed to diesel number 2 having a higher concentration of aromatics and lower volatility than Jet A fuel. Oxides of nitrogen, carbon monoxide, and blowout limits were approximately the same for the two fuels. The air-atomizing nozzle, as compared with the pressure-atomizing nozzle, reduced oxides-of-nitrogen by 20 percent, smoke number by 30 percent, carbon monoxide by 70 percent, and unburned hydrocarbons by 50 percent when used with diesel number 2 fuel.

Altitude-Test-Chamber Investigation of a Solar Afterburner on the 24C Engine I - Operational Characteristics and Altitude Limits

NASA Technical Reports Server (NTRS)

1948-01-01

An altitude-test-chamber investigation was conducted to determine the operational characteristics and altitude blow-out limits of a Solar afterburner in a 24C engine. At rated engine speed and maximum permissible turbine-discharge temperature, the altitude limit as determined by combustion blow-out occurred as a band of unstable operation of about 8000 feet altitude in width with maximum altitude limits from 32,000 feet at a Mach number of 0.3 to about 42,000 feet at a Mach number of 1.0. The maximum fuel-air ratio of the afterburner, as limited by maximum permissible turbine-discharge gas temperatures at rated engine speed, varied between 0.0295 and 0.0380 over a range of flight Mach numbers from 0.25 to 1.0 and at altitudes of 20,000 and 30,000 feet. Over this range of operating conditions, the fuel-air ratio at which lean blow-out occurred was from 10 to 19 percent below these maximum fuel-air ratios. Combustion was very smooth and uniform during operation; however, ignition of the burner was very difficult throughout the investigation. A failure of the flame holder after 12 hours and 15 minutes of afterburner operation resulted in termination of the investigation.

The threats from oil spills: now, then, and in the future.

PubMed

Jernelöv, Arne

2010-01-01

The ongoing oil spill from the blown-out well by the name of Macondo, drilled by the ill-fated rig Deepwater Horizon, has many features in common with another blowout in the Mexican Gulf that happened three decades ago. Then the oil gushed out from the Ixtoc I well drilled by the Sedco 135-F semi-submersible rig. In the years between these catastrophes, the source and nature of oil spills have undergone large changes. Huge spills from tankers that ran aground or collided used to be what caught the headlines and caused large ecological damage. The number and size of such accidental spills have decreased significantly. Instead, spills from ageing, ill-maintained or sabotaged pipelines have increased, and places like Arctic Russia, the Niger Delta, and the northwestern Amazon have become sites of reoccurring oil pollution. As for blowouts, there is no clear trend with regard to the number of incidences or amounts of spilled oil, but deepwater blowouts are much harder to cap and thus tend to go on longer and result in the release of larger quantities of oil. Also, oil exploration and extraction is moving into ever-deeper water and into stormier and icier seas, increasing potential risks. The risk for reoccurring spills like the two huge Mexican Gulf ones is eminent and must be reduced.

Numerical simulations of the Macondo well blowout reveal strong control of oil flow by reservoir permeability and exsolution of gas

PubMed Central

Oldenburg, Curtis M.; Freifeld, Barry M.; Pruess, Karsten; Pan, Lehua; Finsterle, Stefan; Moridis, George J.

2012-01-01

In response to the urgent need for estimates of the oil and gas flow rate from the Macondo well MC252-1 blowout, we assembled a small team and carried out oil and gas flow simulations using the TOUGH2 codes over two weeks in mid-2010. The conceptual model included the oil reservoir and the well with a top boundary condition located at the bottom of the blowout preventer. We developed a fluid properties module (Eoil) applicable to a simple two-phase and two-component oil-gas system. The flow of oil and gas was simulated using T2Well, a coupled reservoir-wellbore flow model, along with iTOUGH2 for sensitivity analysis and uncertainty quantification. The most likely oil flow rate estimated from simulations based on the data available in early June 2010 was about 100,000 bbl/d (barrels per day) with a corresponding gas flow rate of 300 MMscf/d (million standard cubic feet per day) assuming the well was open to the reservoir over 30 m of thickness. A Monte Carlo analysis of reservoir and fluid properties provided an uncertainty distribution with a long tail extending down to 60,000 bbl/d of oil (170 MMscf/d of gas). The flow rate was most strongly sensitive to reservoir permeability. Conceptual model uncertainty was also significant, particularly with regard to the length of the well that was open to the reservoir. For fluid-entry interval length of 1.5 m, the oil flow rate was about 56,000 bbl/d. Sensitivity analyses showed that flow rate was not very sensitive to pressure-drop across the blowout preventer due to the interplay between gas exsolution and oil flow rate. PMID:21730177

Short-range wakefields generated in the blowout regime of plasma-wakefield acceleration

NASA Astrophysics Data System (ADS)

Stupakov, G.

2018-04-01

In the past, calculation of wakefields generated by an electron bunch propagating in a plasma has been carried out in linear approximation, where the plasma perturbation can be assumed small and plasma equations of motion linearized. This approximation breaks down in the blowout regime where a high-density electron driver expels plasma electrons from its path and creates a cavity void of electrons in its wake. In this paper, we develop a technique that allows us to calculate short-range longitudinal and transverse wakes generated by a witness bunch being accelerated inside the cavity. Our results can be used for studies of the beam loading and the hosing instability of the witness bunch in plasma-wakefield and laser-wakefield acceleration.

A case of isolated abducens nerve paralysis in maxillofacial trauma

PubMed Central

Keskin, Elif Seda; Keskin, Ekrem; Atik, Bekir; Koçer, Abdülkadir

2015-01-01

Nervus abducens is a pure motor nerve located in the pons. It retracts the eyeball laterally by stimulating rectus lateralis muscle. In case of their paralysis, diplopia and restriction in the eye movements while looking sideways, are seen. Since the same signs are seen due to the muscle entrapment in blowout fractures, its differential diagnosis has importance in terms of the treatment protocol and avoiding unnecessary operations. In this article, we present a 22-year-old male patient who was referred to our department due to the prediagnosis of blowout fracture following maxillofacial trauma. However, he was diagnosed with abducens nerve paralysis after the consultations and analysis and his restriction of movement was resolved via systemic steroid treatment instead of unnecessary operation. PMID:26981484

Control of an innovative super-capacitor-powered shape-memory-alloy actuated accumulator for blowout preventer

NASA Astrophysics Data System (ADS)

Chen, Jian; Li, Peng; Song, Gangbing; Ren, Zhang

2017-01-01

The design of a super-capacitor-powered shape-memory-alloy (SMA) actuated accumulator for blowout preventer (BOP) presented in this paper featured several advantages over conventional hydraulic accumulators including instant large current drive, quick system response and elimination of need for the pressure conduits. However, the mechanical design introduced two challenges, the nonlinear nature of SMA actuators and the varying voltage provided by a super capacitor, for control system design. A cerebellar model articulation controller (CMAC) feedforward plus PID controller was developed with the aim of compensation for these adverse effects. Experiments were conducted on a scaled down model and experimental results show that precision control can be achieved with the proposed configurations and algorithms.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freifeld, Barry; Oldenburg, Curtis; Jordan, Preston

The 2015-2016 Aliso Canyon/Porter Ranch natural gas well blowout emitted approximately 100,000 tonnes of natural gas (mostly methane, CH 4) over four months. The blowout impacted thousands of nearby residents, who were displaced from their homes. The high visibility of the event has led to increased scrutiny of the safety of natural gas storage at the Aliso Canyon facility, as well as broader concern for natural gas storage integrity throughout the country. This report presents the findings of the DOE National Laboratories Well Integrity Work Group efforts in the four tasks. In addition to documenting the work of the Workmore » Group, this report presents high priority recommendations to improve well integrity and reduce the likelihood and consequences of subsurface natural gas leaks.« less

[Endovascular Treatment for Carotid Blowout Syndrome after Radiation for Esophageal Cancer:A Case Report].

PubMed

Takahashi, Shigefumi; Kawaguchi, Tomohiro; Niizuma, Kuniyasu; Nakagawa, Atsuhiro; Fujimura, Miki; Ogawa, Takenori; Katori, Yukio; Tominaga, Teiji

2017-09-01

Here, we discuss a case of carotid blowout syndrome successfully treated with endovascular parent artery occlusion. A 71-year-old woman underwent treatment for esophageal cancer resection, followed by 50-Gy radiotherapy, 19 years prior. Due to local recurrence, she underwent 66- and 72-Gy radiation treatments at 2 and 4 years after the initial treatment, respectively. Afterward, tracheostomy and enterostomy were performed. This time, she was transported to our emergency department because of acute eruptive bleeding from the tracheal tube. As her vitals indicated shock, emergency endovascular treatment was performed. Digital subtraction angiography revealed that the common carotid artery in the left-sided of the neck had a pseudoaneurysm extruding to the pharyngeal cavity, which was considered to be the lesion responsible for the acute rupture. She was diagnosed as having carotid blowout syndrome. Balloon test occlusion showed that the cross flow via the anterior and posterior communicating arteries was sufficient, so parent artery occlusion was chosen for bleeding control. Carotid bifurcation was preserved to keep the collateral circulation via the external carotid artery. The patient was discharged 22 days after treatment, without any neurological deficits. Although injured vessel removal with high-flow bypass was an ideal treatment to achieve bleeding control without ischemic complication, endovascular treatment can be an efficient second-best treatment. To minimize the risk of late ischemic complications, flow preservation via carotid bifurcation might be important.

Deep-Sea Macrobenthos Community Structure Proximal to the 2010 Macondo Well Blowout (2010-2011)

NASA Astrophysics Data System (ADS)

Briggs, K. B.; Brunner, C. A.; Yeager, K. M.

2017-12-01

Macrobenthos, polycyclic aromatic hydrocarbons (PAH) and sedimentary organic carbon (SOC) were sampled by multicorer in the vicinity of the Deepwater Horizon well head in October 2010 and 2011 to assess the effects of the April 2010 spill. Four stations were sampled east of the well head, four stations were sampled west of the well head, and "control" stations were sampled 58 and 65 km to the southwest. The macrobenthos community, as expected for continental slope/bathyal (water depth 1160-1760 m) benthos, was highly diverse. Polychaetes dominated at all stations, with either crustaceans or mollusks comprising the next most abundant taxon. The stations within five km of the well head showed slightly lower diversity than the more distal stations six months after the blowout. Compared to the "control" station, proportions of suspension feeders were generally depressed at stations with high PAH concentrations. Anomalously high values for abundance and diversity (and PAH) were found at one station 20 km west of the well head. The median body size of macrobenthos was negatively correlated with total PAH concentration, with 74% of the variation in median size explained by variation in PAH, when the anomalous station was excluded. Macrobenthos abundance did not appear to be influenced by SOC. Abundance and diversity of the macrobenthos was generally higher 18 months after the blowout, with measured PAH concentrations diminished to below background level.

Ion response to relativistic electron bunches in the blowout regime of laser-plasma accelerators.

PubMed

Popov, K I; Rozmus, W; Bychenkov, V Yu; Naseri, N; Capjack, C E; Brantov, A V

2010-11-05

The ion response to relativistic electron bunches in the so called bubble or blowout regime of a laser-plasma accelerator is discussed. In response to the strong fields of the accelerated electrons the ions form a central filament along the laser axis that can be compressed to densities 2 orders of magnitude higher than the initial particle density. A theory of the filament formation and a model of ion self-compression are proposed. It is also shown that in the case of a sharp rear plasma-vacuum interface the ions can be accelerated by a combination of three basic mechanisms. The long time ion evolution that results from the strong electrostatic fields of an electron bunch provides a unique diagnostic of laser-plasma accelerators.

Short-range wakefields generated in the blowout regime of plasma-wakefield acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stupakov, G.

In the past, calculation of wakefields generated by an electron bunch propagating in a plasma has been carried out in linear approximation, where the plasma perturbation can be assumed small and plasma equations of motion linearized. This approximation breaks down in the blowout regime where a high-density electron driver expels plasma electrons from its path and creates a cavity void of electrons in its wake. Here in this paper, we develop a technique that allows us to calculate short-range longitudinal and transverse wakes generated by a witness bunch being accelerated inside the cavity. Our results can be used for studiesmore » of the beam loading and the hosing instability of the witness bunch in plasma-wakefield and laser-wakefield acceleration.« less

Characterization of Combustion Dynamics, Detection, and Prevention of an Unstable Combustion State Based on a Complex-Network Theory

NASA Astrophysics Data System (ADS)

Gotoda, Hiroshi; Kinugawa, Hikaru; Tsujimoto, Ryosuke; Domen, Shohei; Okuno, Yuta

2017-04-01

Complex-network theory has attracted considerable attention for nearly a decade, and it enables us to encompass our understanding of nonlinear dynamics in complex systems in a wide range of fields, including applied physics and mechanical, chemical, and electrical engineering. We conduct an experimental study using a pragmatic online detection methodology based on complex-network theory to prevent a limiting unstable state such as blowout in a confined turbulent combustion system. This study introduces a modified version of the natural visibility algorithm based on the idea of a visibility limit to serve as a pragmatic online detector. The average degree of the modified version of the natural visibility graph allows us to detect the onset of blowout, resulting in online prevention.

Flow-diverter in radiation-induced skull base carotid blowout syndrome: do not write it off!

PubMed

Anil, Gopinathan; Zhang, Junwei; Ong, Yew Kwang; Hui, Francis

2017-10-01

Post-radiotherapy carotid blowout syndrome (CBS) of the skull base is a rare but often catastrophic complication of head and neck malignancies. The existing literature on the treatment of this condition with flow-diverting devices (FDD) is extremely limited and disappointing. We present a case of impending CBS in a patient previously irradiated for nasopharyngeal cancer that was successfully treated with use of multiple FDDs, adjunctive endonasal packing and delayed reinforcement with pedicled naso-septal flap, yielding an excellent outcome at 14-months follow-up. Notwithstanding the discouraging results in literature, our anecdotal experience suggests that endovascular reconstruction using FDD could be an option with long-term viability in post-radiotherapy CBS involving the skull base when reinforced with a vascularised naso-septal flap.

Short-range wakefields generated in the blowout regime of plasma-wakefield acceleration

DOE PAGES

Stupakov, G.

2018-04-02

In the past, calculation of wakefields generated by an electron bunch propagating in a plasma has been carried out in linear approximation, where the plasma perturbation can be assumed small and plasma equations of motion linearized. This approximation breaks down in the blowout regime where a high-density electron driver expels plasma electrons from its path and creates a cavity void of electrons in its wake. Here in this paper, we develop a technique that allows us to calculate short-range longitudinal and transverse wakes generated by a witness bunch being accelerated inside the cavity. Our results can be used for studiesmore » of the beam loading and the hosing instability of the witness bunch in plasma-wakefield and laser-wakefield acceleration.« less

Real-Time Control of Lean Blowout in a Turbine Engine for Minimizing No(x) Emissions

NASA Technical Reports Server (NTRS)

Zinn, Ben

2004-01-01

This report describes research on the development and demonstration of a controlled combustor operates with minimal NO, emissions, thus meeting one of NASA s UEET program goals. NO(x) emissions have been successfully minimized by operating a premixed, lean burning combustor (modeling a lean prevaporized, premixed LPP combustor) safely near its lean blowout (LBO) limit over a range of operating conditions. This was accomplished by integrating the combustor with an LBO precursor sensor and closed-loop, rule-based control system that allowed the combustor to operate far closer to the point of LBO than an uncontrolled combustor would be allowed to in a current engine. Since leaner operation generally leads to lower NO, emissions, engine NO, was reduced without loss of safety.

Wind Texture

NASA Image and Video Library

2011-03-23

On Earth, these wind-derived features are called blowouts, where the force of the wind has carved out a crescent-shaped depression in soft, uncemented material like glacial loess. This image is from NASA Mars Odyssey.

Blowout Prevention Act of 2010

THOMAS, 111th Congress

Rep. Waxman, Henry A. [D-CA-30

2010-06-29

House - 07/29/2010 Reported (Amended) by the Committee on Energy and Commerce. H. Rept. 111-581, Part I. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

30 CFR 250.130 - Why does MMS conduct inspections?

Code of Federal Regulations, 2011 CFR

2011-07-01

... approved Exploration Plan or Development and Production Plans; or right-of-use and easement, and other... blowouts, fires, spillages, or other major accidents has been installed and is operating properly according...

The COSIMA experiments and their verification, a data base for the validation of two phase flow computer codes

NASA Astrophysics Data System (ADS)

Class, G.; Meyder, R.; Stratmanns, E.

1985-12-01

The large data base for validation and development of computer codes for two-phase flow, generated at the COSIMA facility, is reviewed. The aim of COSIMA is to simulate the hydraulic, thermal, and mechanical conditions in the subchannel and the cladding of fuel rods in pressurized water reactors during the blowout phase of a loss of coolant accident. In terms of fuel rod behavior, it is found that during blowout under realistic conditions only small strains are reached. For cladding rupture extremely high rod internal pressures are necessary. The behavior of fuel rod simulators and the effect of thermocouples attached to the cladding outer surface are clarified. Calculations performed with the codes RELAP and DRUFAN show satisfactory agreement with experiments. This can be improved by updating the phase separation models in the codes.

Premixing quality and flame stability: A theoretical and experimental study

NASA Technical Reports Server (NTRS)

Radhakrishnan, K.; Heywood, J. B.; Tabaczynski, R. J.

1979-01-01

Models for predicting flame ignition and blowout in a combustor primary zone are presented. A correlation for the blowoff velocity of premixed turbulent flames is developed using the basic quantities of turbulent flow, and the laminar flame speed. A statistical model employing a Monte Carlo calculation procedure is developed to account for nonuniformities in a combustor primary zone. An overall kinetic rate equation is used to describe the fuel oxidation process. The model is used to predict the lean ignition and blow out limits of premixed turbulent flames; the effects of mixture nonuniformity on the lean ignition limit are explored using an assumed distribution of fuel-air ratios. Data on the effects of variations in inlet temperature, reference velocity and mixture uniformity on the lean ignition and blowout limits of gaseous propane-air flames are presented.

RECURRENT SOLAR JETS INDUCED BY A SATELLITE SPOT AND MOVING MAGNETIC FEATURES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jie; Su, Jiangtao; Yin, Zhiqiang

2015-12-10

Recurrent and homologous jets were observed to the west edge of active region NOAA 11513 at the boundary of a coronal hole. We find two kinds of cancellations between opposite polarity magnetic fluxes, inducing the generation of recurrent jets. First, a satellite spot continuously collides with a pre-existing opposite polarity magnetic field and causes recurrent solar jets. Second, moving magnetic features, which emerge near the sunspot penumbra, pass through the ambient plasma and eventually collide with the opposite polarity magnetic field. Among these recurrent jets, a blowout jet that occurred around 21:10 UT is investigated. The rotation of the pre-existingmore » magnetic field and the shear motion of the satellite spot accumulate magnetic energy, which creates the possibility for the jet to experience blowout right from the standard.« less

Developments in new aircraft tire tread materials. [fatigue life of elastomeric materials

NASA Technical Reports Server (NTRS)

Yager, T. J.; Mccarty, J. L.; Riccitiello, S. R.; Golub, M. A.

1976-01-01

Comparative laboratory and field tests were conducted on experimental and state-of-the-art aircraft tire tread materials in a program aimed at seeking new elastomeric materials which would provide improved aircraft tire tread wear, traction, and blowout resistance in the interests of operational safety and economy. The experimental stock was formulated of natural rubber and amorphous vinyl polybutadiene to provide high thermal-oxidative resistance, a characteristic pursued on the premise that thermal oxidation is involved both in the normal abrasion or wear of tire treads and probably in the chain of events leading to blowout failures. Results from the tests demonstrate that the experimental stock provided better heat buildup (hysteresis) and fatigue properties, at least equal wet and dry traction, and greater wear resistance than the state-of-the-art stock.

Simulation and assessment of SO2 toxic environment after ignition of uncontrolled sour gas flow of well blowout in hills.

PubMed

Zhu, Yuan; Chen, Guo-ming

2010-06-15

To study the sulfur dioxide (SO(2)) toxic environment after the ignition of uncontrolled sour gas flow of well blowout, we propose an integrated model to simulate the accident scenario and assess the consequences of SO(2) poisoning. The accident simulation is carried out based on computational fluid dynamics (CFD), which is composed of well blowout dynamics, combustion of sour gas, and products dispersion. Furthermore, detailed complex terrains are built and boundary layer flows are simulated according to Pasquill stability classes. Then based on the estimated exposure dose derived from the toxic dose-response relationship, quantitative assessment is carried out by using equivalent emergency response planning guideline (ERPG) concentration. In this case study, the contaminated areas are graded into three levels, and the areas, maximal influence distances, and main trajectories are predicted. We show that wind drives the contamination and its distribution to spread downwind, and terrains change the distribution shape through spatial aggregation and obstacles. As a result, the most dangerous regions are the downwind areas, the foot of the slopes, and depression areas such as valleys. These cause unfavorable influences on emergency response for accident control and public evacuation. In addition, the effectiveness of controlling the number of deaths by employing ignition is verified in theory. Based on the assessment results, we propose some suggestions for risk assessment, emergency response and accident decision making. Copyright 2010 Elsevier B.V. All rights reserved.

30 CFR 250.448 - What are the BOP pressure tests requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

30 CFR 250.448 - What are the BOP pressure tests requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

30 CFR 250.448 - What are the BOP pressure tests requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the BOP...

Underinflated tires in the United States

DOT National Transportation Integrated Search

2007-02-09

Underinflated tires impact a drivers ability to control a vehicle against skidding, blowouts, and other tire failures. While not a leading cause of highway accidents and fatalities, a NHTSA study shows that, in 1999, underinflated tires contribute...

30 CFR 250.448 - What are the BOP pressure tests requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.448 What are the...

30 CFR 250.440 - What are the general requirements for BOP systems and system components?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements...

Retrospective Case Study in Killdeer, North Dakota

EPA Pesticide Factsheets

This study site was chosen at the request of the state to specifically examine any water resource impacts from a well blowout in September 2010 that resulted in an uncontrolled release of hydraulic fracturing fluids and formation fluids.

[Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

PubMed

Han, Xiao-hui; Zhang, Jia-yu; Cai, Jian-qiu; Shi, Ming-guang

2011-05-10

To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

Afterburner performance of film-vaporizing V-gutters for inlet temperatures up to 1255 K

NASA Technical Reports Server (NTRS)

Branstetter, J. R.; Reck, G. M.

1973-01-01

Combustion tests of five variations of an integral, spray-bar - flameholder combination were conducted in a 0.49-m-diameter duct. Emphasis was on low levels of augmentation. Fuel impinged on guide plates, mixed with a controlled amount of inlet air, vaporized, and was guided into the V-gutter wake. Combustor length was 0.92 m. Good performance was demonstrated at fuel-air ratios less than 0.025 for inlet temperatures of 920 to 1255 K. Maximum combustion efficiency occured in the vicinity of fuel-air ratios of 0.02 and was 92 to 100 percent, depending on the inlet temperature. Lean blowout fuel-air ratios were in the vicinity of 0.005. Improvements in rich-limit blowout resulted from enlarging the guide-flow passageway areas. Other means of extending the operating range are suggested. A simplified afterburner concept for application to advanced engines is described.

Momentum kill procedure can quickly control blowouts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watson, W.D.; Moore, P.

1993-08-30

The momentum kill method can help in quickly regaining control of a blowing well, providing the blowing well rate and fluid properties can be estimated reasonably. The momentum of the kill fluid counteracts and overcomes the flowing momentum of formation fluids. In other words, sufficient mud density pumped at a sufficient rate is directed into the flow stream to force the escaping fluid column back into the well bore. Sufficient kill fluid hydrostatic pressure must be stacked'' in the hole so that the well remains dead after the operation. The momentum kill is not a panacea for all blowouts. Anmore » assessment must be made of the potential problems unique to this method, and certain requirements must be met if the technique is to be successful. The paper discusses some of the considerations for evaluating the use of the momentum kill method.« less

Beam-driven acceleration in ultra-dense plasma media

DOE PAGES

Shin, Young-Min

2014-09-15

Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 10 25 m -3 and 1.6 x 10 28 m -3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlargingmore » the channel radius (r) from 0.2 Ap to 0.6 .Ap in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.« less

Aviation fuel property effects on altitude relight

NASA Technical Reports Server (NTRS)

Venkataramani, K.

1987-01-01

The major objective of this experimental program was to investigate the effects of fuel property variation on altitude relight characteristics. Four fuels with widely varying volatility properties (JP-4, Jet A, a blend of Jet A and 2040 Solvent, and Diesel 2) were tested in a five-swirl-cup-sector combustor at inlet temperatures and flows representative of windmilling conditions of turbofan engines. The effects of fuel physical properties on atomization were eliminated by using four sets of pressure-atomizing nozzles designed to give the same spray Sauter mean diameter (50 + or - 10 micron) for each fuel at the same design fuel flow. A second series of tests was run with a set of air-blast nozzles. With comparable atomization levels, fuel volatility assumes only a secondary role for first-swirl-cup lightoff and complete blowout. Full propagation first-cup blowout were independent of fuel volatility and depended only on the combustor operating conditions.

Transarterial endovascular treatment in the management of life-threatening carotid blowout syndrome in head and neck cancer patients: review of the literature.

PubMed

Dequanter, D; Shahla, M; Paulus, P; Aubert, C; Lothaire, P

2013-12-01

Carotid blowout syndrome is a rare but devastating complication in patients with head and neck malignancy, and is associated with high morbidity and mortality. Bleeding from the carotid artery or its branches is a well-recognized complication following treatment or recurrence of head and neck cancer. It is an emergency situation, and the classical approach to save the patient's life is to ligate the carotid artery. But the surgical treatment is often technically difficult. Endovascular therapies were recently reported as good alternatives to surgical ligation. Retrospective review of three cases of acute or threatened carotid hemorrhage managed by endovascular therapies. Two patients presented with acute carotid blowout, and one patient with a sentinel bleed. Two patients had previously been treated with surgery and chemo radiation. One patient was treated by chemo radiation. Two had developed pharyngocutaneous fistulas, and one had an open necrosis filled wound that surrounded the carotid artery. In two patients, stent placement resolved the acute hemorrhage. In one patient, superselective embolization was done. Mean duration follow-up was 10.2 months. No patient had residual sequelae of stenting or embolization. Management of carotid blow syndrome is very critical and difficult. A multidisciplinary approach is very important in the management of carotid blow syndrome. Correct and suitable management can be life saving. An endovascular technique is a good and effective alternative with much lower morbidity rates than surgical repair or ligation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

30 CFR 250.440 - What are the general requirements for BOP systems and system components?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.440 What...

30 CFR 250.440 - What are the general requirements for BOP systems and system components?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.440 What...

30 CFR 250.440 - What are the general requirements for BOP systems and system components?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.440 What...

Dual-Mode Scramjet Flameholding Operability Measurements

NASA Technical Reports Server (NTRS)

Donohue, James M.

2012-01-01

Flameholding measurements were made in two different direct connect combustor facilities that were designed to simulate a cavity flameholder in the flowfield of a hydrocarbon fueled dual-mode scramjet combustor. The presence of a shocktrain upstream of the flameholder has a significant impact on the inlet flow to the combustor and on the flameholding limits. A throttle was installed in the downstream end of the test rigs to provide the needed back-pressurization and decouple the operation of the flameholder from the backpressure formed by heat release and thermal choking, as in a flight engine. Measurements were made primarily with ethylene fuel but a limited number of tests were also performed with heated gaseous JP-7 fuel injection. The flameholding limits were measured by ramping inlet air temperature down until blowout was observed. The tests performed in the United Technologies Research Center (UTRC) facility used a hydrogen fueled vitiated air heater, Mach 2.2 and 3.3 inlet nozzles, a scramjet combustor rig with a 1.666 by 6 inch inlet and a 0.65 inch deep cavity. Mean blowout temperature measured at the baseline condition with ethylene fuel, the Mach 2.2 inlet and a cavity pressure of 21 psia was 1502 oR. Flameholding sensitivity to a variety of parameters was assessed. Blowout temperature was found to be most sensitive to fuel injection location and fuel flowrates and surprisingly insensitive to operating pressure (by varying both back-pressurization and inlet flowrate) and inlet Mach number. Video imaging through both the bottom and side wall windows was collected simultaneously and showed that the flame structure was quite unsteady with significant lateral movements as well as movement upstream of the flameholder. Experiments in the University of Virginia (UVa) test facility used a Mach 2 inlet nozzle with a 1 inch by 1.5 inch exit cross section, an aspect ratio of 1.5 versus 3.6 in the UTRC facility. The UVa facility tests were designed to measure the sensitivity of flameholding limits to inlet air vitiation by using electrically heated air and adding steam at levels to simulate vitiated air heaters. The measurements showed no significant difference in blowout temperature with inlet air mole fractions of steam from 0 to 6.7%.

30 CFR 250.515 - Blowout prevention equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 250.515 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT... be equipped with the following: (1) A hydraulic-actuating system that provides sufficient accumulator... manual overrides, or alternately, other devices provided to ensure capability of hydraulic operations if...

Fun in the Sun for School-Agers.

ERIC Educational Resources Information Center

Hanus, Maggie

1996-01-01

Tells how caregivers planning summertime theme-oriented special events for children can build enthusiasm, encourage cooperation, and provide fun activities. Presents four themes: (1) "Beach Blast"; (2) "Splash Day"; (3) "Crazy Carnival"; and (4) "Balloon Blowout." Describes several activities in each…

30 CFR 250.450 - What are the recordkeeping requirements for BOP tests?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.450 What are the... the duration of drilling. ...

30 CFR 250.450 - What are the recordkeeping requirements for BOP tests?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.450 What are the... the duration of drilling. ...

30 CFR 250.450 - What are the recordkeeping requirements for BOP tests?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.450 What are the... the duration of drilling. ...

30 CFR 250.440 - What are the general requirements for BOP systems and system components?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.440 What are the general...

Chemical Safety Alert: Shaft Blow-Out Hazard of Check and Butterfly Valves

EPA Pesticide Factsheets

Certain types of check and butterfly valves can undergo shaft-disk separation and fail catastrophically, even when operated within their design limits of pressure and temperature, causing toxic/flammable gas releases, fires, and vapor cloud explosions.

Analysis of Flow Migration in an Ultra-Compact Combustor

DTIC Science & Technology

2011-03-01

Computational Fluid Dynamics . . . . . . . . . . . . . . . 6 UNICORN Unsteady Ignition and Combustion with Reactions . . . . 8 LBO Lean Blowout...the magnitude of enhanced flame speeds due to g- loading using the UNICORN CFD code. The study examined flame propagation for a hydrogen-air mixture in

77 FR 26562 - Mobile Offshore Drilling Unit Dynamic Positioning Guidance

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-04

... regarding a draft policy letter on Dynamic Positioning (DP) Systems, Emergency Disconnect Systems, Blowout... Coast Guard, NOSAC issued the report ``Recommendations for Dynamic Positioning System Design and... DEPARTMENT OF HOMELAND SECURITY Coast Guard [USCG-2011-1106] Mobile Offshore Drilling Unit Dynamic...

76 FR 81957 - Mobile Offshore Drilling Unit Guidance Policy

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-29

... Purpose Dynamic Positioning Systems (DPSs), Emergency Disconnect Systems (EDSs), Blowout Preventers (BOPs..., ``Dynamically Positioned Mobile Offshore Drilling Unit (MODU) Critical Systems, Personnel and Training.'' We... association, business, labor union, etc.). You may review a Privacy Act, system of records notice regarding...

Fibrillar Chromospheric Spicule-Like Counterparts to an EUV and Soft X-Ray Blowout Coronal Jet

NASA Technical Reports Server (NTRS)

Sterling, Alphonse C.; Harra, Louise K.; Moore, Ronald L.

2010-01-01

We observe an erupting jet feature in a solar polar coronal hole, using data from Hinode/SOT, EIS, and XRT, with supplemental data from STEREO/EUVI. From EUV and soft X-ray (SXR) images we identify the erupting feature as a blowout coronal jet: in SXRs it is a jet with bright base, and in EUV it appears as an eruption of relatively cool (approximately 50,000 K) material of horizontal size scale approximately 30" originating from the base of the SXR jet. In SOT Ca II H images the most pronounced analog is a pair of thin (approximately 1") ejections, at the locations of either of the two legs of the erupting EUV jet. These Ca II features eventually rise beyond 45", leaving the SOT field of view, and have an appearance similar to standard spicules except that they are much taller. They have velocities similar to that of "type II" spicules, approximately 100 kilometers per second, and they appear to have spicule-like substructures splitting off from them with horizontal velocity approximately 50 kilometers per second, similar to the velocities of splitting spicules measured by Sterling et al. (2010). Motions of splitting features and of other substructures suggest that the macroscopic EUV jet is spinning or unwinding as it is ejected. This and earlier work suggests that a sub-population of Ca II type II spicules are the Ca II manifestation of portions of larger-scale erupting magnetic jets. A different sub-population of type II spicules could be blowout jets occurring on a much smaller horizontal size scale than the event we observe here.

Emissions due to the natural gas storage well-casing blowout at Aliso Canyon/SS-25

NASA Astrophysics Data System (ADS)

Herndon, Scott; Daube, Conner; Jervis, Dylan; Yacovitch, Tara; Roscioli, Joseph; Curry, Jason; Nelson, David; Knighton, Berk

2017-04-01

The pronounced increase in unconventional gas production in North America over the last fifteen years has intensified interest in understanding emissions and leaks in the supply chain from well pad to end use. Los Angeles, California is home 19 million consumers of natural gas in both industry and domestic end use. The well blowout at Aliso Canyon Natural Gas Storage Facility in the greater Los Angeles area was quantified using the tracer flux ratio method (TFR). Over 400 tracer plume transects were collected, each lasting 15-300 seconds, using instrumentation aboard a mobile platform on 25 days between December 21, 2015 and March 9, 2016. The leak rate from October 23rd to February 11th has been estimated here using a combination of this work (TFR) and the flight mass balance (FMB) data [Conley et al., 2016]. This estimate relies on the TFR data as the most specific SS-25 emission dataset. Scaling the FMB dataset, the leak rate is projected from Oct 23rd to December 21th. Adding up the emissions inferred and measured suggests a total leak burden of 86,022 ± 8,393 metric tons of methane. This work quantified the emissions during the "bottom kill" procedure which halted the primary emission leak. The ethane to methane enhancement ratio observed downwind of the leak site is consistent with the content of ethane in the natural gas at this site and provides definitive evidence that the methane emission rate quantified via tracer flux ratio is not due to a nearby landfill or other potential biogenic sources. Additionally, the TFR approach employed here is assessing only the leaks due to the SS-25 well blowout and excludes other possible emissions at the facility.

LINE-OF-SIGHT SHELL STRUCTURE OF THE CYGNUS LOOP

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uchida, Hiroyuki; Tsunemi, Hiroshi; Katsuda, Satoru

We conducted a comprehensive study on the shell structure of the Cygnus Loop using 41 observation data obtained by the Suzaku and the XMM-Newton satellites. To investigate the detailed plasma structure of the Cygnus Loop, we divided our fields of view into 1042 box regions. From the spectral analysis, the spectra obtained from the limb of the Loop are well fitted by the single-component non-equilibrium ionization plasma model. On the other hand, the spectra obtained from the inner regions are well fitted by the two-component model. As a result, we confirmed that the low-temperature and high-temperature components originated from themore » surrounding interstellar matter (ISM) and the ejecta of the Loop, respectively. From the best-fit results, we showed a flux distribution of the ISM component. The distribution clearly shows the limb-brightening structure, and we found out some low-flux regions. Among them, the south blowout region has the lowest flux. We also found other large low-flux regions at slightly west and northeast from the center. We estimated the former thin shell region to be approx1.{sup 0}3 in diameter and concluded that there exists a blowout along the line of sight in addition to the south blowout. We also calculated the emission measure distribution of the ISM component and showed that the Cygnus Loop is far from the result obtained by a simple Sedov evolution model. From the results, we support that the Cygnus Loop originated from a cavity explosion. The emission measure distribution also suggests that the cavity-wall density is higher in the northeast than that in the southwest. These results suggest that the thickness of the cavity wall surrounding the Cygnus Loop is not uniform.« less

30 CFR 250.615 - Blowout prevention equipment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 250.615 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT...) A hydraulic-actuating system that provides sufficient accumulator capacity to supply 1.5 times the..., other devices provided to ensure capability of hydraulic operations if rig air is lost; (2) A secondary...

30 CFR 250.515 - Blowout prevention equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... foreseeable conditions and circumstances, including subfreezing conditions. The working pressure rating of the BOP system and BOP system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the annular preventer, the...

METHODOLOGY TO EVALUATE THE POTENTIAL FOR GROUND WATER CONTAMINATION FROM GEOTHERMAL FLUID RELEASES

EPA Science Inventory

This report provides analytical methods and graphical techniques to predict potential ground water contamination from geothermal energy development. Overflows and leaks from ponds, pipe leaks, well blowouts, leaks from well casing, and migration from injection zones can be handle...

Comparative Risk Assessment of spill response options for a deepwater oil well blowout: Part 1. Oil spill modeling.

PubMed

French-McCay, Deborah; Crowley, Deborah; Rowe, Jill J; Bock, Michael; Robinson, Hilary; Wenning, Richard; Walker, Ann Hayward; Joeckel, John; Nedwed, Tim J; Parkerton, Thomas F

2018-06-01

Oil spill model simulations of a deepwater blowout in the Gulf of Mexico De Soto Canyon, assuming no intervention and various response options (i.e., subsea dispersant injection SSDI, in addition to mechanical recovery, in-situ burning, and surface dispersant application) were compared. Predicted oil fate, amount and area of surfaced oil, and exposure concentrations in the water column above potential effects thresholds were used as inputs to a Comparative Risk Assessment to identify response strategies that minimize long-term impacts. SSDI reduced human and wildlife exposure to volatile organic compounds; dispersed oil into a large water volume at depth; enhanced biodegradation; and reduced surface water, nearshore and shoreline exposure to floating oil and entrained/dissolved oil in the upper water column. Tradeoffs included increased oil exposures at depth. However, since organisms are less abundant below 200 m, results indicate that overall exposure of valued ecosystem components was minimized by use of SSDI. Copyright © 2018 Elsevier Ltd. All rights reserved.

Comparative risk assessment of spill response options for a deepwater oil well blowout: Part III. Stakeholder engagement.

PubMed

Walker, Ann Hayward; Scholz, Debra; McPeek, Melinda; French-McCay, Deborah; Rowe, Jill; Bock, Michael; Robinson, Hilary; Wenning, Richard

2018-05-25

This paper describes oil spill stakeholder engagement in a recent comparative risk assessment (CRA) project that examined the tradeoffs associated with a hypothetical offshore well blowout in the Gulf of Mexico, with a specific focus on subsea dispersant injection (SSDI) at the wellhead. SSDI is a new technology deployed during the Deepwater Horizon (DWH) oil spill response. Oil spill stakeholders include decision makers, who will consider whether to integrate SSDI into future tradeoff decisions. This CRA considered the tradeoffs associated with three sets of response strategies: (1) no intervention; (2) mechanical recovery, in-situ burning, and surface dispersants; and, (3) SSDI in addition to responses in (2). For context, the paper begins with a historical review of U.S. policy and engagement with oil spill stakeholders regarding dispersants. Stakeholder activities throughout the project involved decision-maker representatives and their advisors to inform the approach and consider CRA utility in future oil spill preparedness. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characteristics of a trapped-vortex (TV) combustor

NASA Technical Reports Server (NTRS)

Hsu, K.-Y.; Gross, L. P.; Trump, D. D.; Roquemore, W. M.

1994-01-01

The characteristics of a Trapped-Vortex (TV) combustor are presented. A vortex is trapped in the cavity established between two disks mounted in tandem. Fuel and air are injected directly into the cavity in such a way as to increase the vortex strength. Some air from the annular flow is also entrained into the recirculation zone of the vortex. Lean blow-out limits of the combustor are determined for a wide range of annular air flow rates. These data indicate that the lean blow-out limits are considerably lower for the TV combustor than for flames stabilized using swirl or bluff-bodies. The pressure loss through the annular duct is also low, being less than 2% for the flow conditions in this study. The instantaneous shape of the recirculation zone of the trapped vortex is measured using a two-color PIV technique. Temperature profiles obtained with CARS indicate a well mixed recirculation zone and demonstrate the impact of primary air injection on the local equivalence ratio.

High-pressure jet cutters improve capping operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abel, L.W.; Campbell, P.J.; Bowden, J.R. Sr.

1995-05-08

Advances in abrasive cutting technology have improved the methods for removing damaged equipment and preparing wellheads for capping. This technology, much of which was refined during well control operations in Kuwait in 1991, can improve the safety and efficiency of capping jobs by cutting wellheads or casing quickly and cleanly. The majority of well control jobs involve one of three types of capping operations: capping to a flange, capping by installing a wellhead, or capping to a casing stub. Capping operations are often the first major step in regaining control of the well during blowout intervention. Proper planning of amore » capping operation must take into account the mass flow rate, combustible nature of the flow, well bore geometry, and operations in the post-capping phase of the project. The paper discusses capping vehicles, tree removal, jet cutters, capping to a flange, capping to a stub, swallowing the stub, spin-on technique, capping on fire, stinging, offshore blowouts, firefighting, pollution control, intervention equipment, and rig removal.« less

Delayed Development of Brain Abscesses Following Stent-Graft Placement in a Head and Neck Cancer Patient Presenting with Carotid Blowout Syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oweis, Yaseen; Gemmete, Joseph J., E-mail: gemmete@umich.edu; Chaudhary, Neeraj

2011-02-15

We describe the delayed development of intracranial abscesses following emergent treatment with a covered stent-graft for carotid blowout syndrome (CBS) in a patient with head and neck cancer. The patient presented with hemoptysis and frank arterial bleeding through the tracheostomy site. A self-expandable stent-graft was deployed across a small pseudoaneurysm arising from the right common carotid artery (RCCA) and resulted in immediate hemostasis. Three months later, the patient suffered a recurrent hemorrhage. CT of the neck demonstrated periluminal fluid around the caudal aspect of the stent-graft with intraluminal thrombus and a small pseudoaneurysm. Subsequently, the patient underwent a balloon testmore » occlusion study and endovascular sacrifice of the RCCA and right internal carotid artery. MRI of the brain demonstrated at least four ring-enhancing lesions within the right cerebral hemisphere consistent with intracranial abscesses that resolved with broad-spectrum antibiotic coverage.« less

Microgravity

NASA Image and Video Library

1997-01-01

Image taken during a ground based investigation of a methane-fueled laminar flame surrounded by co-flowing air. The flame was enclosed in a chamber, and the pressure reduced. As the pressure decreased, the velocity of the flow increased, causing the flame to change from a stabilized condition to near blow-out or extinction.

30 CFR 250.450 - What are the recordkeeping requirements for BOP tests?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.450 What are the... the duration of drilling. [68 FR 8423, Feb. 20, 2003] ...

30 CFR 250.615 - Blowout prevention equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be applied during each mode of pressure control. (b) The minimum BOP system for well-workover operations with the tree removed must meet the appropriate standards from the following table: When The... for well-workover operations with the tree removed must be equipped with the following: (1) A...

What if Things Get Worse? Really Grand Challenges for Modeling and Simulation in a Risky and Complex World or Modeling and Simulation for the "Greater Good"?

NASA Technical Reports Server (NTRS)

Fifrey, Priscilla

2010-01-01

Today Modeling and Simulation-- ---as an important practice or industry or area of expertise ----- is at a complex crossroad - a sort of cyber-highway--where these complexities meet-technical, economic, environmental, geopolitical and cultural. They may converge or collide. Let's not kid ourselves. It is all too much for anyone person or organization Malcolm Gladwell said it. "We have constructed a world in which the potential for high tech catastrophe is embedded in the fabric of everyday life." We are surrounded by problems that scream at us from our television, Internet and social networks along with billboards and protest signs. We face not just high tech catastrophes but, also, landslides, earthquakes, tornados, floods and hurricanes and large-scale criminality. Evil, war, famine and pestilence have not gone away. It is all too much to think about. My friend, George Peabody, who taught me everything I know about power said that addressing such issues requires that we constantly build our network, information resources and the credibility and visibility of our work. That is how we will build the power of simulation so it can change the world --even maybe, save it. We need all the help we can get and give one another because our human early warning systems appear to be out of kilter. We seem to have trouble imagining how small failings can continue to lead to catastrophic disaster. Think about O-rings and blowout preventers. One is reminded of the old nursery rhyme, "For want of a nail, a shoe was lost! for want of a shoe the horse was lost! for want of a rider the battle was lost and so the kingdom fell." Although the investigation will take more time for real answers, it is worrisome that a rig worker reported to the BBC that-- weeks before the explosion of Deep Ocean Horizon. -he identified a leak in the oil rig's safety equipment -the Control Pod of the blowout preventer which has giant shears designed to cut and seal off the well's main pipe. With both electronics and hydraulics, these are effectively the brains of the blowout preventer. No one fixed it, he alleges, they just shut it down and relied on the other control pod -an act deemed unacceptable by petroleum expert, Tad Patzek, at the University of Texas. The US Congress has identified numerous other problems with the blowout preventer, including design problems and unexpected modifications.

Tips for Working with ADHD Students of All Ages.

ERIC Educational Resources Information Center

Robelia, Beth

1997-01-01

Tips for working with students who have attention deficit hyperactivity disorder include putting them in charge of something, providing structure, giving feedback, using logical consequences for unwanted behavior, being patient, teaching in novel ways, helping them with their gear, pairing them with another student, allowing blow-out time, and…

75 FR 64348 - BOEMRE Information Collection Activity: 1010-0182, Increased Safety Measures for Energy...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-19

... No. BOEM-2010-0052] BOEMRE Information Collection Activity: 1010-0182, Increased Safety Measures for... the likelihood of blowouts, loss of well control, fires, spillages, physical obstruction to other... subsequent oil spill in the Gulf of Mexico. These events highlight the importance of ensuring safe operations...

30 CFR 250.444 - What are the choke manifold requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.444 What are the choke... corrosiveness, volume, and abrasiveness of drilling fluids and well fluids that you may encounter. (b) Choke...

30 CFR 250.444 - What are the choke manifold requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.444 What are the choke manifold..., and abrasiveness of drilling fluids and well fluids that you may encounter. (b) Choke manifold...

30 CFR 250.444 - What are the choke manifold requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.444 What are the choke manifold..., and abrasiveness of drilling fluids and well fluids that you may encounter. (b) Choke manifold...

30 CFR 250.444 - What are the choke manifold requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.444 What are the choke manifold..., and abrasiveness of drilling fluids and well fluids that you may encounter. (b) Choke manifold...

30 CFR 250.516 - Blowout prevention equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... pressure rating of the BOP system and BOP system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the...-control procedure that indicates how the annular preventer will be utilized, and the pressure limitations...

30 CFR 250.516 - Blowout prevention equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pressure rating of the BOP system and BOP system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the...-control procedure that indicates how the annular preventer will be utilized, and the pressure limitations...

30 CFR 250.616 - Blowout prevention equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... pressure rating of the BOP system and system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the... pressure limitations that will be applied during each mode of pressure control. (b) The minimum BOP system...

30 CFR 250.616 - Blowout prevention equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pressure rating of the BOP system and system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the... pressure limitations that will be applied during each mode of pressure control. (b) The minimum BOP system...

30 CFR 250.615 - Blowout prevention equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... pressure rating of the BOP system and system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the... pressure limitations that will be applied during each mode of pressure control. (b) The minimum BOP system...

30 CFR 250.515 - Blowout prevention equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... pressure rating of the BOP system and BOP system components shall exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the...-control procedure that indicates how the annular preventer will be utilized, and the pressure limitations...

78 FR 10685 - Reports, Forms, and Recordkeeping Requirements: Agency Information Collection Activity Under OMB...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-14

... Traffic Safety Administration Title: Tire Pressure Monitoring Systems Special Studies. OMB Number: 2174...: Improperly inflated tires pose a safety risk, increasing the chance of skidding, hydroplaning, longer stopping distances, and crashes due to flat tires and blowouts. In an effort to decrease the number of...

Distribution, morphometry and land use of Delmarva bays

USDA-ARS?s Scientific Manuscript database

Delmarva Bays are depressional wetlands that are elliptical in shape with sandy rims, and occur mainly in the central portion of the Delmarva Peninsula within the Mid-Atlantic United States. It is postulated that they began as wind blowouts during the Pleistocene that filled with water and became e...

Evidence of sulfate-dependent anaerobic methane oxidation within an area impacted by coalbed methane-related gas migration

EPA Science Inventory

The rapid development of unconventional gas resources has been accompanied by an increase in public awareness regarding the potential effects of drilling operations on drinking water sources. Incidents have been reported involving blowouts (e.g., Converse County, WY; Lawrence Tow...

78 FR 72688 - Information Collection Activities: Application for Permit To Drill; Proposed Collection; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... and natural gas resources in a manner that is consistent with the need to make such resources... prevent or minimize the likelihood of blowouts, loss of well control, fires, spillages, physical... the environment or to property or endanger life or health.'' In addition to the general rulemaking...

77 FR 28401 - Information Collection Activities: Legacy Data Verification Process (LDVP); Submitted for Office...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-14

... and natural gas resources in a manner that is consistent with the need to make such resources... to prevent or minimize the likelihood of blowouts, loss of well control, fires, spillages, physical... the environment or to property, or endanger life or health.'' BSEE's Legacy Data Verification Process...

Instability of a witness bunch in a plasma bubble

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burov, A.; Lebedev, V.; Nagaitsev, S.

2016-02-16

The stability of a trailing witness bunch, accelerated by a plasma wake accelerator (PWA) in a blow-out regime, is discussed. The instability growth rate as well as the energy spread, required for BNS damping, are obtained. A relationship between the PWA power efficiency and the BNS energy spread is derived.

30 CFR 250.616 - Blowout preventer system testing, records, and drills.

Code of Federal Regulations, 2011 CFR

2011-07-01

... drills. 250.616 Section 250.616 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND... drills. (a) BOP pressure tests. When you pressure test the BOP system you must conduct a low-pressure... engaged in well-workover operations shall participate in a weekly BOP drill to familiarize crew members...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2013 CFR

2013-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.446 - What are the BOP maintenance and inspection requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.446 What are the... Prevention Equipment Systems for Drilling Wells (incorporated by reference as specified in § 250.198). You...

30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2012 CFR

2012-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.434 - What are the recordkeeping requirements for diverter actuations and tests?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.434 What are the recordkeeping... the facility for the duration of drilling the well. Blowout Preventer (BOP) System Requirements ...

30 CFR 250.449 - What additional BOP testing requirements must I meet?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.449 What additional BOP... water to conduct this test. You may use drilling fluids to conduct subsequent tests of a subsea BOP...

30 CFR 250.449 - What additional BOP testing requirements must I meet?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.449 What additional BOP... water to conduct this test. You may use drilling fluids to conduct subsequent tests of a subsea BOP...

30 CFR 250.451 - What must I do in certain situations involving BOP equipment or systems?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements... drilling activities. If you encounter the following situation: Then you must . . . (a) BOP equipment does...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2014 CFR

2014-07-01

... THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure test the BOP... BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed since your...

30 CFR 250.446 - What are the BOP maintenance and inspection requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.446 What are the BOP... for Drilling Wells (as incorporated by reference in § 250.198). You must document the procedures used...

30 CFR 250.434 - What are the recordkeeping requirements for diverter actuations and tests?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.434 What are the recordkeeping... the facility for the duration of drilling the well. Blowout Preventer (BOP) System Requirements ...

30 CFR 250.447 - When must I pressure test the BOP system?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.447 When must I pressure... valves, inside BOP, and drill-string safety valve): (a) When installed; (b) Before 14 days have elapsed...

30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF SAFETY AND ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System...

30 CFR 250.449 - What additional BOP testing requirements must I meet?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.449 What... installation. You must use water to conduct this test. You may use drilling fluids to conduct subsequent tests...

30 CFR 250.446 - What are the BOP maintenance and inspection requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.446 What are the BOP... for Drilling Wells (incorporated by reference as specified in § 250.198). You must document how you...

30 CFR 250.446 - What are the BOP maintenance and inspection requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.446 What are the BOP... for Drilling Wells (incorporated by reference as specified in § 250.198). You must document how you...

30 CFR 250.434 - What are the recordkeeping requirements for diverter actuations and tests?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Diverter System Requirements § 250.434 What are the recordkeeping... the facility for the duration of drilling the well. Blowout Preventer (BOP) System Requirements ...

30 CFR 250.449 - What additional BOP testing requirements must I meet?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.449 What additional BOP... water to conduct this test. You may use drilling fluids to conduct subsequent tests of a subsea BOP...

30 CFR 250.443 - What associated systems and related equipment must all BOP systems include?

Code of Federal Regulations, 2011 CFR

2011-07-01

... MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System... must be on the drilling floor. You must locate the other station in a readily accessible location away...

30 CFR 250.1706 - What are the requirements for blowout prevention equipment?

Code of Federal Regulations, 2014 CFR

2014-07-01

... circumstances, including subfreezing conditions. The working pressure rating of the BOP system and system components must exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the annular preventer, you must submit with Form BSEE-0124...

30 CFR 250.1706 - What are the requirements for blowout prevention equipment?

Code of Federal Regulations, 2013 CFR

2013-07-01

... circumstances, including subfreezing conditions. The working pressure rating of the BOP system and system components must exceed the expected surface pressure to which they may be subjected. If the expected surface pressure exceeds the rated working pressure of the annular preventer, you must submit with Form BSEE-0124...

30 CFR 250.516 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... inspection, whichever is longer. (2) You must visually inspect your BOP system and marine riser at least once.... The District Manager may approve alternate methods and frequencies to inspect a marine riser. (h) BOP... drills, and inspections of the BOP system, system components, and marine riser in the driller's report...

30 CFR 250.517 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... on a daily basis. You must visually inspect your subsea BOP system and marine riser at least once... equipment. The BSEE District Manager may approve alternate methods and frequencies to inspect a marine riser..., actuations, crew drills, and inspections of the BOP system, system components, and marine riser in the...

30 CFR 250.517 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... on a daily basis. You must visually inspect your subsea BOP system and marine riser at least once... equipment. The BSEE District Manager may approve alternate methods and frequencies to inspect a marine riser..., actuations, crew drills, and inspections of the BOP system, system components, and marine riser in the...

76 FR 50748 - Information Collection Activity: Production Safety Systems, Revision of a Collection; Submitted...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-16

... Production Safety Systems. OMB Control Number: 1010-0059. Abstract: The Outer Continental Shelf (OCS) Lands..., precautions, and techniques sufficient to prevent or minimize the likelihood of blowouts, loss of well control... an identifiable non-Federal recipient above and beyond those which accrue to the public at large...

Effect of Spray Cone Angle on Flame Stability in an Annular Gas Turbine Combustor

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Kumar, S. Kishore; Chandel, Sunil

2016-04-01

Effect of fuel spray cone angle in an aerogas turbine combustor has been studied using computational fluid dynamics (CFD) and full-scale combustor testing. For CFD analysis, a 22.5° sector of an annular combustor is modeled and the governing equations are solved using the eddy dissipation combustion model in ANSYS CFX computational package. The analysis has been carried out at 125 kPa and 303 K inlet conditions for spray cone angles from 60° to 140°. The lean blowout limits are established by studying the behavior of combustion zone during transient engine operation from an initial steady-state condition. The computational study has been followed by testing the practical full-scale annular combustor in an aerothermal test facility. The experimental result is in a good agreement with the computational predictions. The lean blowout fuel-air ratio increases as the spray cone angle is decreased at constant operating pressure and temperature. At higher spray cone angle, the flame and high-temperature zone moves upstream close to atomizer face and a uniform flame is sustained over a wide region causing better flame stability.

Lean stability augmentation study. [on gas turbine combustion chambers

NASA Technical Reports Server (NTRS)

Mcvey, J. B.; Kennedy, J. B.

1979-01-01

An analytical conceptual design study and an experimental test program were conducted to investigate techniques and develop technology for improving the lean combustion limits of premixing, prevaporizing combustors applicable to gas turbine engine main burners. The use of hot gas pilots, catalyzed flameholder elements, and heat recirculation to augment lean stability limits was considered in the conceptual design study. Tests of flameholders embodying selected concepts were conducted at a pressure of 10 arm and over a range of entrance temperatures simulating conditions to be encountered during stratospheric cruise. The tests were performed using an axisymmetric flametube test rig having a nominal diameter of 10.2 cm. A total of sixteen test configurations were examined in which lean blowout limits, pollutant emission characteristics, and combustor performance were evaluated. The use of a piloted perforated plate flameholder employing a pilot fuel flow rate equivalent to 4 percent of the total fuel flow at a simulated cruise condition resulted in a lean blowout equivalence ratio of less than 0.25 with a design point (T sub zero = 600k, Phi = 0.6) NOx emission index of less than 1.0 g/kg.

Risk of Carotid Blowout After Reirradiation of the Head and Neck: A Systematic Review

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, Mark W., E-mail: mwmcdona@iupui.edu; Indiana University Health Proton Therapy Center, Bloomington, IN; Moore, Michael G.

2012-03-01

Purpose: Carotid blowout (CB) is a rare but frequently fatal complication of head-and-neck (H and N) cancer or its treatment. We sought to determine the reported rate of CB in patients receiving salvage reirradiation for H and N cancer. Methods and Materials: A literature search identified 27 published articles on H and N reirradiation involving 1554 patients, and a pooled analysis was performed to determine the rate of CB. Treatment parameters, including prior radiation dose, interval from prior radiation, dose and fractionation of reirradiation, use of salvage surgery, and chemotherapy, were abstracted and summarized. The cumulative risk of CB wasmore » compared between groups using Fisher's exact test. Results: Among 1554 patients receiving salvage H and N reirradiation, there were 41 reported CBs, for a rate of 2.6%; 76% were fatal. In patients treated in a continuous course with 1.8-2-Gy daily fractions or 1.2-Gy twice-daily fractions, 36% of whom received concurrent chemotherapy, the rate of CB was 1.3%, compared with 4.5% in patients treated with 1.5 Gy twice daily in alternating weeks or with delayed accelerated hyperfractionation, all of whom received concurrent chemotherapy (p = 0.002). There was no statistically significant difference in the rate of CB between patients treated with or without concurrent chemotherapy, or between patients treated with or without salvage surgery before reirradiation. Conclusion: Carotid blowout is an infrequent but serious complication of salvage reirradiation for H and N cancer. The rate of CB was lower among patients treated with conventional or hyperfractionated schedules compared with regimens of accelerated hyperfractionation, though heterogeneous patient populations and treatment parameters preclude definite conclusions. Given the high mortality rate of CB, discussion of the risk of CB is an important component of informed consent for salvage reirradiation.« less

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2010 CFR

2010-07-01

... equipment subject to well and/or pump pressure shall have a rated working pressure at least as great as the... manifold with a pressure rating at least as great as the rated working pressure of the ram-type BOP's..., the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to provide either of...

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2011 CFR

2011-07-01

... pressure at least as great as the rated working pressure of the ram-type BOP's or as otherwise approved by..., and including, the choke manifold with a pressure rating at least as great as the rated working...-string operations, the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to...

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2014 CFR

2014-07-01

... equipment subject to well and/or pump pressure shall have a rated working pressure at least as great as the... manifold with a pressure rating at least as great as the rated working pressure of the ram-type BOP's..., the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to provide either of...

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2012 CFR

2012-07-01

... equipment subject to well and/or pump pressure shall have a rated working pressure at least as great as the... manifold with a pressure rating at least as great as the rated working pressure of the ram-type BOP's..., the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to provide either of...

30 CFR 250.1610 - Blowout preventer systems and system components.

Code of Federal Regulations, 2013 CFR

2013-07-01

... equipment subject to well and/or pump pressure shall have a rated working pressure at least as great as the... manifold with a pressure rating at least as great as the rated working pressure of the ram-type BOP's..., the BOP stack shall be equipped with conventional and/or variable-bore pipe rams to provide either of...

78 FR 72693 - Information Collection Activities: Application for Permit To Modify; Proposed Collection; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-03

... natural gas resources in a manner that is consistent with the need to make such resources available to... minimize the likelihood of blowouts, loss of well control, fires, spillages, physical obstructions to other... environment or to property or endanger life or health.'' In addition to the general authority of OCSLA...

30 CFR 250.443 - What associated systems and related equipment must all BOP systems include?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.443 What... all BOP components. (b) At least two BOP control stations. One station must be on the drilling floor...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.442 - What are the requirements for a subsea BOP system?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.442 What are the requirements for a subsea BOP system? When you drill with a subsea BOP system, you must install the BOP system...

30 CFR 250.451 - What must I do in certain situations involving BOP equipment or systems?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.451 What must I... actions that lessees must take when certain situations occur with BOP systems during drilling activities...

30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources MINERALS MANAGEMENT SERVICE, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.445 What...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.445 - What are the requirements for kelly valves, inside BOPs, and drill-string safety valves?

Code of Federal Regulations, 2011 CFR

2011-07-01

..., inside BOPs, and drill-string safety valves? 250.445 Section 250.445 Mineral Resources BUREAU OF OCEAN ENERGY MANAGEMENT, REGULATION, AND ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop...

30 CFR 250.451 - What must I do in certain situations involving BOP equipment or systems?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.451 What must I do in... lessees must take when certain situations occur with BOP systems during drilling activities. If you...

30 CFR 250.442 - What are the requirements for a subsea BOP system?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.442 What are the requirements for a subsea BOP system? When you drill with a subsea BOP system, you must install the BOP system...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.451 - What must I do in certain situations involving BOP equipment or systems?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.451 What must I... actions that lessees must take when certain situations occur with BOP systems during drilling activities...

30 CFR 250.442 - What are the requirements for a subsea BOP system?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.442 What are the requirements for a subsea BOP system? When you drill with a subsea BOP system, you must install the BOP system...

30 CFR 250.441 - What are the requirements for a surface BOP stack?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.441 What are the requirements for a surface BOP stack? (a) When you drill with a surface BOP stack, you must install the BOP...

30 CFR 250.442 - What are the requirements for a subsea BOP system?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.442 What are the requirements for a subsea BOP system? When you drill with a subsea BOP system, you must install the BOP system...

30 CFR 250.443 - What associated systems and related equipment must all BOP systems include?

Code of Federal Regulations, 2010 CFR

2010-07-01

..., DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.443 What associated systems... components. (b) At least two BOP control stations. One station must be on the drilling floor. You must locate...

30 CFR 250.443 - What associated systems and related equipment must all BOP systems include?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.443 What... all BOP components. (b) At least two BOP control stations. One station must be on the drilling floor...

30 CFR 250.443 - What associated systems and related equipment must all BOP systems include?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.443 What... all BOP components. (b) At least two BOP control stations. One station must be on the drilling floor...

30 CFR 250.451 - What must I do in certain situations involving BOP equipment or systems?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENFORCEMENT, DEPARTMENT OF THE INTERIOR OFFSHORE OIL AND GAS AND SULPHUR OPERATIONS IN THE OUTER CONTINENTAL SHELF Oil and Gas Drilling Operations Blowout Preventer (bop) System Requirements § 250.451 What must I... actions that lessees must take when certain situations occur with BOP systems during drilling activities...

30 CFR 250.516 - Blowout preventer system tests, inspections, and maintenance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... marine riser at least once each day if weather and sea conditions permit. You may use television cameras... inspect a marine riser. (h) BOP maintenance. You must maintain your BOP system to ensure that the... components, and marine riser in the driller's report. In addition, you must: (1) Record BOP test pressures on...

30 CFR 250.1611 - Blowout preventer systems tests, actuations, inspections, and maintenance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... conducting high-pressure tests, all BOP systems shall be tested to a pressure of 200 to 300 psi. (b) Ram-type BOP's and the choke manifold shall be pressure tested with water to rated working pressure or as otherwise approved by the District Manager. Annular type BOP's shall be pressure tested with water to 70...

30 CFR 250.1624 - Blowout prevention equipment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... station and one BOP-control station on the rig floor; and (5) A choke line and a kill line each equipped with two full-opening valves and a choke manifold. One of the choke-line valves and one of the kill-line valves shall be remotely controlled except that a check valve may be installed on the kill line in...

30 CFR 250.1624 - Blowout prevention equipment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... station and one BOP-control station on the rig floor; and (5) A choke line and a kill line each equipped with two full-opening valves and a choke manifold. One of the choke-line valves and one of the kill-line valves shall be remotely controlled except that a check valve may be installed on the kill line in...

30 CFR 250.1624 - Blowout prevention equipment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... station and one BOP-control station on the rig floor; and (5) A choke line and a kill line each equipped with two full-opening valves and a choke manifold. One of the choke-line valves and one of the kill-line valves shall be remotely controlled except that a check valve may be installed on the kill line in...

30 CFR 250.1624 - Blowout prevention equipment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... station and one BOP-control station on the rig floor; and (5) A choke line and a kill line each equipped with two full-opening valves and a choke manifold. One of the choke-line valves and one of the kill-line valves shall be remotely controlled except that a check valve may be installed on the kill line in...

Desensitizing Flame Structure and Exhaust Emissions to Flow Parameters in an Ultra-Compact Combustor

DTIC Science & Technology

2012-03-22

fuel .... 9 Figure 2.4: UNICORN model of hydrogen in air flame front propagation under the loading condition (a) 10 g’s and (b) 500 g’s...Lean Blowout ...................................................................................8 UNICORN Unsteady Ignition and Combustion with...computationally recreate Lewis’ experimental results. Using the Unsteady Ignition and 9 Combustion with Reactions ( UNICORN ) code, flame propagation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zilkha, A.

Computed tomographic (CT) findings in four patients with isolated blow-out fracture of the medial orbital wall are reported. CT delineated the fracture site and its extent in each case, and clearly demonstrated medial rectus muscle entrapment in two. This was confirmed by surgery. CT was found superior to polytomography and proved to be the best radiologic means for the diagnosis of medial orbital wall fracture and muscle entrapment.

Predicting The Intrusion Layer From Deep Ocean Oil Spills

NASA Astrophysics Data System (ADS)

Wang, Dayang; Chow, Aaron; Adams, E. Eric

2015-11-01

Oil spills from deep ocean blowout events motivate our study of multiphase plumes in a water column. Key to understanding the long-term fate of these plumes is the ability to predict the depth and persistence of intrusion layers. While intrusion layers from multiphase plumes have been studied under stagnant conditions, their behavior in the presence of crossflow, especially in mild crossflow, remains poorly understood. The classical classification of plume behavior identifies two regimes: crossflow-dominant and stratification-dominant--but it does not account for the interplay between the two effects, leaving the transition region unexplored. We conduct laboratory tank experiments to investigate the behavior of intrusion layers under the simultaneous action of crossflow and stratification. Our experiments use an inverted frame of reference, using glass beads with a range of sizes to simulate oil droplets. We find that crossflow creates enhanced mixing, which in turn leads to a shallower intrusion layer of the released fluid (correspondingly, a deeper layer in the case of a deep ocean blowout). We develop a mathematical formulation that extends previous models to account for crossflow effects, and use field observations to validate the analytical and experimental findings.

Reirradiation for second primary or recurrent cancers of the head and neck: Dosimetric and outcome analysis.

PubMed

Garg, Shivank; Kilburn, Jeremy M; Lucas, John T; Randolph, David; Urbanic, James J; Hinson, William H; Kearns, William T; Porosnicu, Mercedes; Greven, Kathryn

2016-04-01

The purpose of this study was to examine outcomes, toxicity, and dosimetric characteristics of patients treated with reirradiation for head and neck cancers. Fifty patients underwent ≥2 courses of radiation therapy (RT) postoperatively or definitively with or without chemotherapy. Composite dose volume histograms (DVHs) for selected anatomic structures were correlated with grade ≥3 late toxicity. Median initial and retreatment radiation dose was 64 and 60 Gy, respectively. Median overall survival (OS), progression-free survival (PFS), and 1-year PFS rates were 18 months, 11 months, and 45%, respectively, with 13 months median follow-up. Thirty-four percent of patients experienced grade ≥3 late toxicity with 1 death from carotid blowout. The DVH corresponding to the carotid blowout fell above the third quartile compared with other patients. Our analysis is the first to systematically evaluate the dose to the carotid artery using composite dosimetry in head and neck reirradiation patients, and demonstrates a promising technique for evaluating the dose to other normal tissue structures. © 2015 Wiley Periodicals, Inc. Head Neck 38: E961-E969, 2016. © 2015 Wiley Periodicals, Inc.

Quantifying the flow rate of the Deepwater Horizon Macondo Well oil spill

NASA Astrophysics Data System (ADS)

Camilli, R.; Bowen, A.; Yoerger, D. R.; Whitcomb, L. L.; Techet, A. H.; Reddy, C. M.; Sylva, S.; Seewald, J.; di Iorio, D.; Whoi Flow Rate Measurement Group

2010-12-01

The Deepwater Horizon blowout in the Mississippi Canyon block 252 of the Gulf of Mexico created the largest recorded offshore oil spill. The well outflow’s multiple leak sources, turbulent multiphase flow, tendency for hydrate formation, and extreme source depth of 1500 m below the sea surface complicated the quantitative estimation of oil and gas leakage rates. We present methods and results from a U.S. Coast Guard sponsored flow assessment study of the Deepwater Horizon’s damaged blow out preventer and riser. This study utilized a remotely operated vehicle equipped with in-situ acoustic sensors (a Doppler sonar and an imaging multibeam sonar) and isobaric gas-tight fluid samplers to measure directly outflow from the damaged well. Findings from this study indicate oil release rates and total release volume estimates that corroborate estimates made by the federal government’s Flow Rate Technical Group using non-acoustic techniques. The acoustic survey methods reported here provides a means for estimating fluid flow rates in subsurface environments, and are potentially useful for a diverse range of oceanographic applications. Photograph of the Discoverer Enterprise burning natural gas collected from the Macondo well blowout preventer during flow measurement operations. Copyright Wood Hole Oceanographic Institution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Winter, J.R.; Keywood, S.S.

PTFE-based gaskets in chemical plant service typically fail in an extrusion mode, sometimes referred to as blowout. Test work previously published by Monsanto indicated that correctly installed PTFE-based gaskets have pressure performance far exceeding system pressure ratings. These results have since been confirmed by extensive testing at the Montreal based Ecole Polytechnique Tightness Testing and Research Laboratory (TTRL), funded by a consortium of gasket users and manufacturers. With the knowledge that properly installed gaskets can withstand system pressures in excess of 1,000 psig [6,894 kPa], failures at two chemical plants were re-examined. This analysis indicates that extrusion type failures canmore » be caused by excessive internal pressures, associated with sections of pipe having an external source of heat coincident with a blocked flow condition. This results in high system pressures which explain the extrusion type failures observed. The paper discusses details of individual failures and examines methods to prevent them. Other causes for extrusion failures are reviewed, with a recommendation that stronger gasket materials not be utilized to correct problems until it is verified that excessive pressure build-up is not the problem. Also summarized are the requirements for proper installation to achieve the potential blowout resistance found in these gaskets.« less

Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hidding, B.; Rosenzweig, J. B.; Xi, Y.

2012-12-21

An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed 'Trojan Horse' acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment 'E-210: Trojanmore » Horse Plasma Wakefield Acceleration' has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.« less

ON THE OBSERVATION AND SIMULATION OF SOLAR CORONAL TWIN JETS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiajia; Wang, Yuming; Zhang, Quanhao

We present the first observation, analysis, and modeling of solar coronal twin jets, which occurred after a preceding jet. Detailed analysis on the kinetics of the preceding jet reveals its blowout-jet nature, which resembles the one studied in Liu et al. However, the erupting process and kinetics of the twin jets appear to be different from the preceding one. Lacking detailed information on the magnetic fields in the twin jet region, we instead use a numerical simulation using a three-dimensional (3D) MHD model as described in Fang et al., and find that in the simulation a pair of twin jetsmore » form due to reconnection between the ambient open fields and a highly twisted sigmoidal magnetic flux, which is the outcome of the further evolution of the magnetic fields following the preceding blowout jet. Based on the similarity between the synthesized and observed emission, we propose this mechanism as a possible explanation for the observed twin jets. Combining our observation and simulation, we suggest that with continuous energy transport from the subsurface convection zone into the corona, solar coronal twin jets could be generated in the same fashion addressed above.« less

Effects of Fuel Composition on Combustion Stability and NO X Emissions for Traditional and Alternative Jet Fuels

NASA Astrophysics Data System (ADS)

Vijlee, Shazib Z.

Synthetic jet fuels are studied to help understand their viability as alternatives to traditionally derived jet fuel. Two combustion parameters -- flame stability and NOX emissions -- are used to compare these fuels through experiments and models. At its core, this is a fuels study comparing how chemical makeup and behavior relate. Six 'real', complex fuels are studied in this work -- four are synthetic from alternative sources and two are traditional from petroleum sources. Two of the synthetic fuels are derived from natural gas and coal via the Fischer Tropsch catalytic process. The other two are derived from Camelina oil and tallow via hydroprocessing. The traditional military jet fuel, JP8, is used as a baseline as it is derived from petroleum. The sixth fuel is derived from petroleum and is used to study the effects of aromatic content on the synthetic fuels. The synthetic fuels lack aromatic compounds, which are an important class of hydrocarbons necessary for fuel handling systems to function properly. Several single-component fuels are studied (through models and/or experiments) to facilitate interpretation and understanding. The flame stability study first compares all the 'real', complex fuels for blowout. A toroidal stirred reactor is used to try and isolate temperature and chemical effects. The modeling study of blowout in the toroidal reactor is the key to understanding any fuel-based differences in blowout behavior. A detailed, reacting CFD model of methane is used to understand how the reactor stabilizes the flame and how that changes as the reactor approaches blowout. A 22 species reduced form of GRI 3.0 is used to model methane chemistry. The knowledge of the radical species role is utilized to investigate the differences between a highly aliphatic fuel (surrogated by iso-octane) and a highly aromatic fuel (surrogated by toluene). A perfectly stirred reactor model is used to study the chemical kinetic pathways for these fuels near blowout. The differences in flame stabilization can be attributed to the rate at which these fuels are attacked and destroyed by radical species. The slow disintegration of the aromatic rings reduces the radical pool available for chain-initiating and chain-branching, which ultimately leads to an earlier blowout. The NOX study compares JP8, the aromatic additive, the synthetic fuels with and without an aromatic additive, and an aromatic surrogate (1,3,5-trimethylbenzene). A jet stirred reactor is used to try and isolate temperature and chemical effects. The reactor has a volume of 15.8 mL and a residence time of approximately 2.5 ms. The fuel flow rate (hence equivalence ratio) is adjusted to achieve nominally consistent temperatures of 1800, 1850, and 1900K. Small oscillations in fuel flow rate cause the data to appear in bands, which facilitated Arrhenius-type NOX-temperature correlations for direct comparison between fuels. The fuel comparisons are somewhat inconsistent, especially when the aromatic fuel is blended into the synthetic fuels. In general, the aromatic surrogate (1,3,5-trimethylbenzene) produces the most NOX, followed by JP8. The synthetic fuels (without aromatic additive) are always in the same ranking order for NOX production (HP Camelina > FT Coal > FT Natural Gas > HP Tallow). The aromatic additive ranks differently based on the temperature, which appears to indicate that some of the differences in NOX formation are due to the Zeldovich NOX formation pathway. The aromatic additive increases NOX for the HP Tallow and decreases NOX for the FT Coal. The aromatic additive causes increased NOX at low temperatures but decreases NOX at high temperatures for the HP Camelina and FT Natural Gas. A single perfectly stirred reactor model is used with several chemical kinetic mechanisms to study the effects of fuel (and fuel class) on NO X formation. The 27 unique NOX formation reactions from GRI 3.0 are added to published mechanisms for jet fuel surrogates. The investigation first looked at iso-octane and toluene and found that toluene produces more NOX because of a larger pool of O radical. The O radical concentration was lower for iso-octane because of an increased concentration of methyl (CH 3) radical that consumes O radical readily. Several surrogate fuels (iso-octane, toluene, propylcyclohexane, n-octane, and 1,3,5-trimethylbenzene) are modeled to look for differences in NOX production. The trend (increased CH3 → decreased O → decreased NOX) is consistently true for all surrogate fuels with multiple kinetic mechanisms. It appears that the manner in which the fuel disintegrates and creates methyl radical is an extremely important aspect of how much NOX a fuel will produce. (Abstract shortened by UMI.).

Dispersant Effectiveness, In-Situ Droplet Size Distribution and Numerical Modeling to Assess Subsurface Dispersant Injection as a Deepwater Blowout Oil Spill Response Option and Evaluation of Oil Fluorescence Characteristics to Improve Forensic Response Tools

EPA Science Inventory

This report summarizes two projects covered under an Interagency Agreement between the Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Environmental Protection Agency (EPA) in collaboration with the Bedford Institute of Oceanography, Department of Fisheries and...

Demography and monitoring of Welsh's milkweed (Asclepias welshii) at Coral Pink Sand Dunes

Treesearch

Brent C. Palmer; L. Armstrong

2001-01-01

Results are presented of a 12-year monitoring program on the Coral Pink Sand Dunes and Sand Hills populations of the threatened Welsh's milkweed, Asclepias welshii N & P Holmgren. The species is an early sera1 member of the dune flora, colonizing blowouts and advancing with shifting dunes. When an area stabilizes and other vegetation encroaches, A. welshii is...

Inductive shearing of drilling pipe

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ludtka, Gerard M.; Wilgen, John; Kisner, Roger

Induction shearing may be used to cut a drillpipe at an undersea well. Electromagnetic rings may be built into a blow-out preventer (BOP) at the seafloor. The electromagnetic rings create a magnetic field through the drillpipe and may transfer sufficient energy to change the state of the metal drillpipe to shear the drillpipe. After shearing the drillpipe, the drillpipe may be sealed to prevent further leakage of well contents.

77 FR 11158 - Notice of Lodging of Proposed Consent Decree Under the Clean Water Act

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-24

... Notice is hereby given that on February 17, 2012, a proposed Consent Decree in In Re: Oil Spill by the Oil Rig ``Deepwater Horizon'' in the Gulf of Mexico, on April 20, 2010, MDL 2179, was lodged with the... discharge of oil into the Gulf of Mexico resulting from the April 20, 2010 blowout of the Macondo well and...

The History All around Us: Roosevelt High School and the 1968 Eastside Blowouts

ERIC Educational Resources Information Center

Gibbs, Brian C.

2011-01-01

A text can be anything: a poem, a map, an old letter. To spur great learning, it needs to be provocative, powerful, open to multiple interpretations, and, above all, it needs to teach something profound. A school building can also become text when a teacher uses place as a way to make history come alive. The author discusses how he uses Theodore…

Flame blowout and pollutant emissions in vitiated combustion of conventional and bio-derived fuels

NASA Astrophysics Data System (ADS)

Singh, Bhupinder

The widening gap between the demand and supply of fossil fuels has catalyzed the exploration of alternative sources of energy. Interest in the power, water extraction and refrigeration (PoWER) cycle, proposed by the University of Florida, as well as the desirability of using biofuels in distributed generation systems, has motivated the exploration of biofuel vitiated combustion. The PoWER cycle is a novel engine cycle concept that utilizes vitiation of the air stream with externally-cooled recirculated exhaust gases at an intermediate pressure in a semi-closed cycle (SCC) loop, lowering the overall temperature of combustion. It has several advantages including fuel flexibility, reduced air flow, lower flame temperature, compactness, high efficiency at full and part load, and low emissions. Since the core engine air stream is vitiated with the externally cooled exhaust gas recirculation (EGR) stream, there is an inherent reduction in the combustion stability for a PoWER engine. The effect of EGR flow and temperature on combustion blowout stability and emissions during vitiated biofuel combustion has been characterized. The vitiated combustion performance of biofuels methyl butanoate, dimethyl ether, and ethanol have been compared with n-heptane, and varying compositions of syngas with methane fuel. In addition, at high levels of EGR a sharp reduction in the flame luminosity has been observed in our experimental tests, indicating the onset of flameless combustion. This drop in luminosity may be a result of inhibition of processes leading to the formation of radiative soot particles. One of the objectives of this study is finding the effect of EGR on soot formation, with the ultimate objective of being able to predict the boundaries of flameless combustion. Detailed chemical kinetic simulations were performed using a constant-pressure continuously stirred tank reactor (CSTR) network model developed using the Cantera combustion code, implemented in C++. Results have been presented showing comparative trends in pollutant emissions generation, flame blowout stability, and combustion efficiency. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

In search of thermogenic methane in groundwater in the Netherlands, with emphasis on the location of a historic gas well blowout

NASA Astrophysics Data System (ADS)

Schout, G.; Griffioen, J.; Hassanizadeh, S. M.; Hartog, N.

2017-12-01

Similar to the US, the Netherlands has a long history of oil & gas production, with around 2500 onshore hydrocarbon wells drilled since the late 1930s. While conventional reserves are diminishing, a governmental moratorium was put in place on shale gas exploration and production until 2023, in part due to concerns about its effects on groundwater quality. To investigate the industry's historic and potential future impact on groundwater quality in the country, a study was carried out to assess i) baseline methane concentrations and origin ii) the natural connectivity of deeper gas-bearing layers with the shallower groundwater systems. Through datamining, a dataset consisting of 12,200 groundwater analyses with methane concentrations was assembled. Furthermore, 25 additional samples were collected at targeted locations and analysed for dissolved gas molecular and isotopic composition. Methane concentrations are positively skewed with median, mean and maximum concentrations of 0.28, 2.17 and 120 mg/L, respectively. No correlation between methane concentrations and distance to hydrocarbon wells or faults is observed. In general, concentrations cannot be readily explained by factors such as the depth, geographic location, host formation and depositional environment. Thermogenic methane was first encountered at several hundred meters depth, below thick successions of marine Paleogene and Neogene clays that are present throughout the country and impede vertical flow. All methane encountered above these formations was found to be biogenic in origin, with one notable exception - a sample taken at the site of a catastrophic gas well blowout that occurred in 1965 near the village of Sleen. Combined, these findings suggest that thermogenic methane does not naturally occur in Dutch shallow groundwater and its presence can be used as an indicator of anthropogenic gas leakage. The unique Sleen blowout site was selected for a detailed investigation of the long-term effects of uncontrolled gas leakage on groundwater chemistry. Methane concentrations up to 45 mg/L were observed and the distribution pattern suggests on-going leakage, 50 years after the events. Results also show that anaerobic oxidation of methane plays a major role in controlling the spread of dissolved methane.

What happens between pure hydraulic and buckling mechanisms of blowout fractures?

PubMed

Nagasao, Tomohisa; Miyamoto, Junpei; Shimizu, Yusuke; Jiang, Hua; Nakajima, Tatsuo

2010-06-01

The present study aims to evaluate how the ratio of the hydraulic and buckling mechanisms affects blowout fracture patterns, when these two mechanisms work simultaneously. Three-dimensional computer-aided-design (CAD)models were generated simulating ten skulls. To simulate impact, 1.2J was applied on the orbital region of these models in four patterns. Pattern 1: All the energy works to cause the hydraulic effect. Pattern 2: Two-thirds of the energy works to cause the hydraulic effect; one-third of the energy works to cause the buckling effect. Pattern 3: One-third of the energy works to cause the hydraulic effect; two-thirds of the energy works to cause the buckling effect. Pattern 4: The entire energy quantum works to cause the buckling effect. Using the finite element method, the regions where fractures were theoretically expected to occur were calculated and were compared between the four patterns. More fracture damage occurred for Pattern 1 than Pattern 2, and for Pattern 3 than for Pattern 4. The hydraulic and buckling mechanisms interact with one another. When these two mechanisms are combined, the orbital walls tend to develop serious fractures. Copyright (c) 2009 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Scientific basis for safely shutting in the Macondo Well after the April 20, 2010 Deepwater Horizon blowout

USGS Publications Warehouse

Hickman, Stephen H.; Hsieh, Paul A.; Mooney, Walter D.; Enomoto, Catherine B.; Nelson, Philip H.; Flemings, Peter; Mayer, Larry; Moran, Kathryn; Weber, Thomas; McNutt, Marcia K.; Rice, James R.

2012-01-01

As part of the government response to the Deepwater Horizon blowout, a Well Integrity Team evaluated the geologic hazards of shutting in the Macondo Well at the seafloor and determined the conditions under which it could safely be undertaken. Of particular concern was the possibility that, under the anticipated high shut-in pressures, oil could leak out of the well casing below the seafloor. Such a leak could lead to new geologic pathways for hydrocarbon release to the Gulf of Mexico. Evaluating this hazard required analyses of 2D and 3D seismic surveys, seafloor bathymetry, sediment properties, geophysical well logs, and drilling data to assess the geological, hydrological, and geomechanical conditions around the Macondo Well. After the well was successfully capped and shut in on July 15, 2010, a variety of monitoring activities were used to assess subsurface well integrity. These activities included acquisition of wellhead pressure data, marine multichannel seismic profiles, seafloor and water-column sonar surveys, and wellhead visual/acoustic monitoring. These data showed that the Macondo Well was not leaking after shut in, and therefore, it could remain safely shut until reservoir pressures were suppressed (killed) with heavy drilling mud and the well was sealed with cement.

Trace element distributions in the water column near the Deepwater Horizon well blowout.

PubMed

Joung, DongJoo; Shiller, Alan M

2013-03-05

To understand the impact of the Deepwater Horizon well blowout on dissolved trace element concentrations, samples were collected from areas around the oil rig explosion site during four cruises in early and late May 2010, October 2010, and October 2011. In surface waters, Ba, Fe, Cu, Ni, Mn, and Co were relatively well correlated with salinity during all cruises, suggesting mixing with river water was the main influence on metal distributions in these waters. However, in deep oil/gas plumes (1000-1400 m depth), modestly elevated concentrations of Co and Ba were observed in late May, compared with postblowout conditions. Analysis of the oil itself along with leaching experiments confirm the oil as the source of the Co, whereas increased Ba was likely due to drilling mud used in the top kill attempt. Deep plume dissolved Mn largely reflected natural benthic input, though some samples showed slight elevation probably associated with the top kill. Dissolved Fe concentrations were low and also appeared largely topographically controlled and reflective of benthic input. Estimates suggest that microbial Fe demand may have affected the Fe distribution but probably not to the extent of Fe becoming a growth-limiting factor. Experiments showed that the dispersant can have some limited impact on dissolved-particulate metal partitioning.

Effects of oil from the 2010 Macondo well blowout on marsh foraminifera of Mississippi and Louisiana, USA.

PubMed

Brunner, Charlotte A; Yeager, Kevin M; Hatch, Rachel; Simpson, Sondra; Keim, Joseph; Briggs, Kevin B; Louchouarn, Patrick

2013-08-20

Foraminifera responded to both heavy and light oiling of marshes relative to unoiled control sites by changes to both standing stock and depth of habitation (DOH) in sediment following the 2010 Macondo well blowout. Push cores were taken from the middle marsh at sites classified as unoiled, lightly oiled, and heavily oiled based on concentrations of total polycyclic aromatic hydrocarbons ([TPAH]). Cores were sliced and stained with rose Bengal to detect live specimens of foraminifera. Short-term, sediment-mixing depths were determined using the penetration depths of excess (234)Th, and sedimentary organic carbon and carbonate were measured to distinguish depositional environments. Marsh foraminifera reacted to the highest oil concentration (5,000-18,000 ng/g of TPAH) by reducing standing stock and shortening the DOH compared with the control sites. At a second, less heavily oiled site, foraminifera responded with a shallower DOH, but with a boom in standing stock. Deformed, dead foraminifera occurred in all heavily oiled cores-but not elsewhere. Live foraminifera responded with a population boom at lightly oiled sites with [TPAH] near 1,100 ng/g. Changes in standing stock and DOH with [TPAH] suggest disturbance to the marsh food web, apparently due to oil pollution, and support the use of foraminifera as sentinel species.

ON THE MAGNETIC AND ENERGY CHARACTERISTICS OF RECURRENT HOMOLOGOUS JETS FROM AN EMERGING FLUX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jiajia; Wang, Yuming; Liu, Rui

In this paper, we present the detailed analysis of recurrent homologous jets originating from an emerging negative magnetic flux at the edge of an active region. The observed jets show multithermal features. Their evolution shows high consistence with the characteristic parameters of the emerging flux, suggesting that with more free magnetic energy, the eruptions tend to be more violent, frequent, and blowout-like. The average temperature, average electron number density, and axial speed are found to be similar for different jets, indicating that they should have been formed by plasmas from similar origins. Statistical analysis of the jets and their footpointmore » region conditions reveals a strong positive relationship between the footpoint region total 131 Å intensity enhancement and jets’ length/width. Stronger linearly positive relationships also exist between the total intensity enhancement/thermal energy of the footpoint regions and jets’ mass/kinetic/thermal energy, with higher cross-correlation coefficients. All the above results together confirm the direct relationship between the magnetic reconnection and the jets and validate the important role of magnetic reconnection in transporting large amounts of free magnetic energy into jets. It is also suggested that there should be more free energy released during the magnetic reconnection of blowout than of standard jet events.« less

Lean Blow-out Studies in a Swirl Stabilized Annular Gas Turbine Combustor

NASA Astrophysics Data System (ADS)

Mishra, R. K.; Kishore Kumar, S.; Chandel, Sunil

2015-05-01

Lean blow out characteristics in a swirl stabilized aero gas turbine combustor have been studied using computational fluid dynamics. For CFD analysis, a 22.5° sector of an annular combustor is modeled using unstructured tetrahedral meshes comprising 1.2 × 106 elements. The governing equations are solved using the eddy dissipation combustion model in CFX. The primary combustion zone is analyzed by considering it as a well stirred reactor. The analysis has been carried out for different operating conditions of the reactants entering into the control volume. The results are treated as the base-line or reference values. Combustion lean blow-out limits are further characterized studying the behavior of combustion zone during transient engine operation. The validity of the computational study has been established by experimental study on a full-scale annular combustor in an air flow test facility that is capable of simulating different conditions at combustor inlet. The experimental result is in a good agreement with the analytical predictions. Upon increasing the combustor mass flow, the lean blow out limit increases, i.e., the blow out occurs at higher fuel-air ratios. In addition, when the operating pressure decreases, the lean blow out limit increases, i.e., blow out occurs at higher fuel-air ratios.

Use of fascia-peritoneum patch as a pledget for an infected aortic stump.

PubMed

Sarac, Timur P; Augustinos, Peter; Lyden, Sean; Ouriel, Kenneth

2003-12-01

Treatment of aortic prosthetic graft infections remains a challenge. One frequently encountered technical difficulty when removing an infected prosthetic aortic graft is how to close a short, friable remnant aortic stump. We present three case reports in which we used a layer of posterior rectus fascia-peritoneum to bolster oversewing a short infected aortic stump after removal of an infected aortic graft. All three patients underwent staged extra-anatomic axillary-to-femoral artery bypass procedures, with subsequent removal of the infected aortic graft as a second operation. Two of the three procedures were semi-elective, and one was done urgently because of a recurrent aortoenteric fistula. All three patients had less than 1 cm of remaining aortic neck below the renal arteries for closure. In each instance a segment of autogenous posterior rectus fascia-peritoneum was harvested and used as a circumferential pledget to bolster the anastomosis. No patient had stump blowout, and in no case was there computed tomography evidence of aneurysmal enlargement of the stump with follow-up of 12 and 24 months in two of the three survivors. Use of autogenous fascia-peritoneum is a durable and effective method to assist stump closure and prevent stump blowout after removal of infected aortic grafts.

Explosive parcel containment and blast mitigation container

DOEpatents

Sparks, Michael H.

2001-06-12

The present invention relates to a containment structure for containing and mitigating explosions. The containment structure is installed in the wall of the building and has interior and exterior doors for placing suspicious packages into the containment structure and retrieving them from the exterior of the building. The containment structure has a blast deflection chute and a blowout panel to direct over pressure from explosions away from the building, surrounding structures and people.

Air pollution from aircraft

NASA Technical Reports Server (NTRS)

Heywood, J. B.; Fay, J. A.; Chigier, N. A.

1979-01-01

A series of fundamental problems related to jet engine air pollution and combustion were examined. These include soot formation and oxidation, nitric oxide and carbon monoxide emissions mechanisms, pollutant dispension, flow and combustion characteristics of the NASA swirl can combustor, fuel atomization and fuel-air mixing processes, fuel spray drop velocity and size measurement, ignition and blowout. A summary of this work, and a bibliography of 41 theses and publications which describe this work, with abstracts, is included.

Enceladus' near-surface CO2 gas pockets and surface frost deposits

NASA Astrophysics Data System (ADS)

Matson, Dennis L.; Davies, Ashley Gerard; Johnson, Torrence V.; Combe, Jean-Philippe; McCord, Thomas B.; Radebaugh, Jani; Singh, Sandeep

2018-03-01

Solid CO2 surface deposits were reported in Enceladus' South Polar Region by Brown et al. (2006). They noted that such volatile deposits are temporary and posited ongoing replenishment. We present a model for this replenishment by expanding on the Matson et al. (2012) model of subsurface heat and chemical transport in Enceladus. Our model explains the distributions of both CO2 frost and complexed CO2 clathrate hydrate as seen in the Cassini Visual and Infrared Mapping Spectrometer (VIMS) data. We trace the journey of CO2 from a subsurface ocean. The ocean-water circulation model of Matson et al. (2012) brings water up to near the surface where gas exsolves to form bubbles. Some of the CO2 bubbles are trapped and form pockets of gas in recesses at the bottom of the uppermost ice layer. When fissures break open these pockets, the CO2 gas is vented. Gas pocket venting is episodic compared to the more or less continuous eruptive plumes, emanating from the "tiger stripes", that are supported by plume chambers. Two styles of gas pocket venting are considered: (1) seeps, and (2) blowouts. The presence of CO2 frost patches suggests that the pocket gas slowly seeped through fractured, cold ice and when some of the gas reached the surface it was cold enough to condense (i.e., T ∼70 to ∼119 K). If the fissure opening is large, a blowout occurs. The rapid escape of gas and drop in pocket pressure causes water in the pocket to boil and create many small aerosol droplets of seawater. These may be carried along by the erupting gas. Electrically charged droplets can couple to the magnetosphere, and be dragged away from Enceladus. Most of the CO2 blowout gas escapes from Enceladus and the remainder is distributed globally. However, CO2 trapped in a clathrate structure does not escape. It is much heavier and slower moving than the CO2 gas. Its motion is ballistic and has an average range of about 17 km. Thus, it contributes to deposits in the vicinity of the vent. Local heat flow indicates that gas pockets can be located as deep as several tens of meters below the surface. Gas pockets can be reused, and we explore their life cycle.

Flame Propagation and Blowout in Hydrocarbon Jets: Experiments to Understand the Stability and Structure

DTIC Science & Technology

2012-07-29

Wilson and Kevin M. Lyons. On Diluted-Fuel Combustion Issues in Burning Biogas Surrogates, ASME-JERT, (12 2009): . doi: 2010/01/07 10:47:38 2 TOTAL...four coflow velocities are used, resulting in eight additional flow configurations. Table 2 contains the data obtained for these configurations, as...counterflow have higher stability limits than those in an oblique configuration. 4.) Conclusions Based on the results obtained from this experiment, a

Transient and steady-state performance of a single turbojet combustor with four different fuel nozzles

NASA Technical Reports Server (NTRS)

Mccafferty, Richard J; Donlon, Richard H

1955-01-01

Acceleration and steady-state performance of a tubular combustor was evaluated at two simulated altitudes with four different fuel nozzles. Temperature response lag was observed with all the nozzles. Except for rich-limit blowout, the only combustion failures observed during acceleration were with a fuel nozzle that gave an interrupted flow delivery during the acceleration. This same nozzle, because of superior fuel atomization, gave the highest steady-state combustion efficiencies.

Holocene geoarchaeology of the Sixteen Mile Beach barrier dunes in the Western Cape, South Africa

NASA Astrophysics Data System (ADS)

Compton, John S.; Franceschini, Giuliana

2005-01-01

Holocene evolution and human occupation of the Sixteen Mile Beach barrier dunes on the southwest coast of South Africa between Yzerfontein and Saldanha Bay are inferred from the radiocarbon ages of calcareous dune sand, limpet shell ( Patella spp.) manuports and gull-dropped white mussel shells ( Donax serra). A series of coast-parallel dunes have prograded seaward in response to an overall marine regression since the mid-Holocene with dated shell from relict foredunes indicating periods of shoreline progradation that correspond to drops in sea level at around 5900, 4500 and 2400 calibrated years before the present (cal yr B.P.). However, the active foredune, extensively covered by a layer of gull-dropped shell, has migrated 500 m inland by the recycling of eroded dune sand in response to an approximate 1 m sea level rise over the last 700 yr. Manuported limpet shells from relict blowouts on landward vegetated dunes indicate human occupation of coastal dune sites at 6200 and 6000 cal yr B.P. and help to fill the mid-Holocene gap in the regional archaeological record. Coastal midden shells associated with small hearth sites exposed in blowouts on the active foredune are contemporaneous (1600-500 cal yr B.P.) with large midden sites on the western margin of Langebaan Lagoon and suggest an increase in marine resource utilisation associated with the arrival of pastoralism in the Western Cape.

OBSERVATIONS OF A SERIES OF FLARES AND ASSOCIATED JET-LIKE ERUPTIONS DRIVEN BY THE EMERGENCE OF TWISTED MAGNETIC FIELDS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lim, Eun-Kyung; Yurchyshyn, Vasyl; Kim, Sujin

We studied temporal changes of morphological and magnetic properties of a succession of four confined flares followed by an eruptive flare using the high-resolution New Solar Telescope (NST) operating at the Big Bear Solar Observatory (BBSO) and Helioseismic and Magnetic Imager (HMI) magnetograms and Atmospheric Image Assembly (AIA) EUV images provided by the Solar Dynamics Observatory (SDO). From the NST/Hα and the SDO/AIA 304 Å observations we found that each flare developed a jet structure that evolved in a manner similar to evolution of the blowout jet: (1) an inverted-Y-shaped jet appeared and drifted away from its initial position; (2) jets formed amore » curtain-like structure that consisted of many fine threads accompanied by subsequent brightenings near the footpoints of the fine threads; and finally, (3) the jet showed a twisted structure visible near the flare maximum. Analysis of the HMI data showed that both the negative magnetic flux and the magnetic helicity have been gradually increasing in the positive-polarity region, indicating the continuous injection of magnetic twist before and during the series of flares. Based on these results, we suggest that the continuous emergence of twisted magnetic flux played an important role in producing successive flares and developing a series of blowout jets.« less

Broad Low-Intensity Wings in the Emission-Line Profiles of Four Wolf-Rayet Galaxies

NASA Astrophysics Data System (ADS)

Méndez, David I.; Esteban, César

1997-10-01

High-resolution spectroscopic observations have been obtained for the Wolf-Rayet galaxies He 2-10, II Zw 40, POX 4, and Tol 35. Several subregions have been selected in each slit position in order to investigate possible spatial variations in the line profiles, radial velocities, and ionization conditions of the gas. The most remarkable feature of the spectra is the presence of asymmetric broad low-intensity wings in the profiles of the brightest emission lines. These spectral features are detected farther out from the star-forming knots, showing linear dimensions between 300 pc and 4.1 kpc. The maximum expansion velocity measured for this gas is between 120 and 340 km s-1 and appears to be quite constant along the slit for all the objects. Additional general properties of the spectra are (1) the quoted emission-line ratios are similar in the narrow and broad components, (2) no systematic differences of the behavior of the broad and narrow components have been found along the major and minor axis of the galaxies, and (3) the spatial distribution of the ionized gas is peaked centrally. Different mechanisms capable of producing the observed broad spectral features are discussed: cloud-cloud collisions in virialized gas, ``academic'' superbubbles, champagne flows, and superbubble blowout. It is concluded that superbubble blowout expanding over a cloudy medium can explain the observational properties in a reasonable manner.

Advanced Gas Turbine (AGT): Power-train system development

NASA Technical Reports Server (NTRS)

Helms, H. E.; Johnson, R. A.; Gibson, R. K.; Smith, L. B.

1983-01-01

Technical work on the design and effort leading to the testing of a 74.5 kW (100 hp) automotive gas turbine is described. The general effort was concentrated on building an engine for test starting in July. The buildup progressed with only routine problems and the engine was delivered to the test stand 9 July. In addition to the engine build effort, work continued in selected component areas. Ceramic turbine parts were built and tested. Burst tests of ceramic rotors show strengths are approaching that achieved in test bars; proof testing is required for acceptable strength ceramic vanes. Over 25 hours was accumulated on the combustor rig in three test modes: pilot nozzle only, start nozzle, and main nozzle operation. Satisfactory ignition was achieved for a wide range of starting speeds and the lean blowout limit was as low as 0.06 kg/b (0.14 lb/hr). Lean blowout was more a function of nozzle atomization than fuel/air ratio. A variety of cycle points were tested. Transition from start nozzle flow to main nozzle flow was done manually without difficulty. Regenerator parts were qualification tested without incident and the parts were assembled on schedule. Rig based performance matched first build requirements. Repeated failures in the harmonic drive gearbox during rig testing resulted in that concept being abandoned for an alternate scheme.

Anomalously High Recruitment of the 2010 Gulf Menhaden (Brevoortia patronus) Year Class: Evidence of Indirect Effects from the Deepwater Horizon Blowout in the Gulf of Mexico.

PubMed

Short, Jeffrey W; Geiger, Harold J; Haney, J Christopher; Voss, Christine M; Vozzo, Maria L; Guillory, Vincent; Peterson, Charles H

2017-07-01

Gulf menhaden (Brevoortia patronus) exhibited unprecedented juvenile recruitment in 2010 during the year of the Deepwater Horizon well blowout, exceeding the prior 39-year mean by more than four standard deviations near the Mississippi River. Abundance of that cohort remained exceptionally high for two subsequent years as recruits moved into older age classes. Such changes in this dominant forage fish population can be most parsimoniously explained as consequences of release from predation. Contact with crude oil induced high mortality of piscivorous seabirds, bottlenose dolphin (Tursiops truncatus), waders, and other fish-eating marsh birds, all of which are substantial consumers of Gulf menhaden. Diversions of fresh water from the Mississippi River to protect coastal marshes from oiling depressed salinities, impairing access to juvenile Gulf menhaden by aquatic predators that avoid low-salinity estuarine waters. These releases from predation led to an increase of Gulf menhaden biomass in 2011 to 2.4 million t, or more than twice the average biomass of 1.1 million t for the decade prior to 2010. Biomass increases of this magnitude in a major forage fish species suggest additional trophically linked effects at the population-, trophic-level and ecosystem scales, reflecting an heretofore little appreciated indirect effect that may be associated with major oil spills in highly productive marine waters.

Hydrocarbon composition and concentrations in the Gulf of Mexico sediments in the 3 years following the Macondo well blowout.

PubMed

Babcock-Adams, Lydia; Chanton, Jeffrey P; Joye, Samantha B; Medeiros, Patricia M

2017-10-01

In April of 2010, the Macondo well blowout in the northern Gulf of Mexico resulted in an unprecedented release of oil into the water column at a depth of approximately 1500 m. A time series of surface and subsurface sediment samples were collected to the northwest of the well from 2010 to 2013 for molecular biomarker and bulk carbon isotopic analyses. While no clear trend was observed in subsurface sediments, surface sediments (0-3 cm) showed a clear pattern with total concentrations of n-alkanes, unresolved complex mixture (UCM), and petroleum biomarkers (terpanes, hopanes, steranes) increasing from May to September 2010, peaking in late November 2010, and strongly decreasing in the subsequent years. The peak in hydrocarbon concentrations were corroborated by higher organic carbon contents, more depleted Δ 14 C values and biomarker ratios similar to those of the initial MC252 crude oil reported in the literature. These results indicate that at least part of oil discharged from the accident sedimented to the seafloor in subsequent months, resulting in an apparent accumulation of hydrocarbons on the seabed by the end of 2010. Sediment resuspension and transport or biodegradation may account for the decrease in sedimented oil quantities in the years following the Macondo well spill. Copyright © 2017 Elsevier Ltd. All rights reserved.

Blow-out protector and fire control system for petroleum exploration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caraway, M.F.; Caraway, B.L.

1987-10-06

A blow-out protector is described for an oil well comprising a housing having a vertical passageway therethrough for a Kelly. The housing has a lower end adapter flange to be connected to a well casing, an elastomeric body having an opening for the Kelly and carried on the Kelly for providing sealing contact with the Kelly and housing passageway, a catch ring secured to the Kelly and having a surface defined by a given diameter, a compressor ring plate positioned below the elastomeric body on the Kelly, means on an interior of the housing having a given diameter and preventingmore » the compressor ring plate from falling down and yet providing engagement with the surface of the catch ring, the compressor ring plate having a hole for passage of the Kelly drive-mechanism for the drill pipe, the catch ring on the Kelly positioned below the compressor plate. The diameter of the catch ring is smaller than the diameter of the interior means on the housing so that when the Kelly is pulled up the catch ring will contact and force the compressor ring plate against the elastomeric body and force the elastomeric body into tight contact with both the Kelly and the housing thus sealing the space between the Kelly and the housing against a blow-out.« less

Natural and Unnatural Oil Layers on the Surface of the Gulf of Mexico Detected and Quantified in Synthetic Aperture RADAR Images with Texture Classifying Neural Network Algorithms

NASA Astrophysics Data System (ADS)

MacDonald, I. R.; Garcia-Pineda, O. G.; Morey, S. L.; Huffer, F.

2011-12-01

Effervescent hydrocarbons rise naturally from hydrocarbon seeps in the Gulf of Mexico and reach the ocean surface. This oil forms thin (~0.1 μm) layers that enhance specular reflectivity and have been widely used to quantify the abundance and distribution of natural seeps using synthetic aperture radar (SAR). An analogous process occurred at a vastly greater scale for oil and gas discharged from BP's Macondo well blowout. SAR data allow direct comparison of the areas of the ocean surface covered by oil from natural sources and the discharge. We used a texture classifying neural network algorithm to quantify the areas of naturally occurring oil-covered water in 176 SAR image collections from the Gulf of Mexico obtained between May 1997 and November 2007, prior to the blowout. Separately we also analyzed 36 SAR images collections obtained between 26 April and 30 July, 2010 while the discharged oil was visible in the Gulf of Mexico. For the naturally occurring oil, we removed pollution events and transient oceanographic effects by including only the reflectance anomalies that that recurred in the same locality over multiple images. We measured the area of oil layers in a grid of 10x10 km cells covering the entire Gulf of Mexico. Floating oil layers were observed in only a fraction of the total Gulf area amounting to 1.22x10^5 km^2. In a bootstrap sample of 2000 replications, the combined average area of these layers was 7.80x10^2 km^2 (sd 86.03). For a regional comparison, we divided the Gulf of Mexico into four quadrates along 90° W longitude, and 25° N latitude. The NE quadrate, where the BP discharge occurred, received on average 7.0% of the total natural seepage in the Gulf of Mexico (5.24 x10^2 km^2, sd 21.99); the NW quadrate received on average 68.0% of this total (5.30 x10^2 km^2, sd 69.67). The BP blowout occurred in the NE quadrate of the Gulf of Mexico; discharged oil that reached the surface drifted over a large area north of 25° N. Performing a similar estimate using 5x5 km grid cells, we observed discharged oil over an area of 1.20x10^5 km^2; 91% of this area was east of 90° W. The average area oil covered water observed in the SAR images was 4.41x104^ km^2, 98% of which was observed in the eastern Gulf. Numerical oil spill model experiments are used to clarify the distinction between the area impacted by the BP oil spill and the surface slicks due to known natural seeps. Natural oil seepage has been cited as a background source of hydrocarbon contamination in the Gulf of Mexico. Our direct comparison shows that during the blowout, the discharged oil impacted an average area two orders of magnitude greater than the entire Gulf total and three orders of magnitude greater than the usual dose received in the northeastern region. Because the layers of discharged oil were often many times thicker than natural seep oil, additional scale factors are required to show the true difference in doses. These differences should be weighed when evaluating the relative impact of natural and unnatural oil in a large marine ecosystem.

A Crashworthiness Analysis with Emphasis on the Fire Hazard: U.S. and Selected Foreign Turbine Aircraft Accidents, 1964-1974

DTIC Science & Technology

1976-07-01

1965 Summary, Pg. 11 21. 6/14/65, DC-8, , Santiago , Chile Left main landing gear brakes were locked on touchdown causing tire blowouts and a small fire... concentration of nine percent will prevent an explosion such as hat which occurred under similar ex- ternal fire test conditions in an tudnerted fuel tank. These...the inert concentration in the tanks was lost, providing more time for safe evacuation. Liquid nitrogen fuel tank inerting technology is presently

Some Operating Experience and Problems Encountered During Operation of a Free-jet Facility

NASA Technical Reports Server (NTRS)

Mcaulay, John E; Prince, William R

1957-01-01

During a free-jet investigation of a 28-inch ram-jet engine at a Mach number of 2.35, flow pulsation at the engine inlet were discovered which proved to have an effect on the engine performance and operational characteristics, particularly the engine rich blowout limits. This report discusses the finding of the flow pulsations, their elimination, and effect. Other facility characteristics, such as the establishment of flow simulation and the degree of subcritical operation of the diffuser, are also explained.

Advancements in dynamic kill calculations for blowout wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kouba, G.E.; MacDougall, G.R.; Schumacher, B.W.

1993-09-01

This paper addresses the development, interpretation, and use of dynamic kill equations. To this end, three simple calculation techniques are developed for determining the minimum dynamic kill rate. Two techniques contain only single-phase calculations and are independent of reservoir inflow performance. Despite these limitations, these two methods are useful for bracketing the minimum flow rates necessary to kill a blowing well. For the third technique, a simplified mechanistic multiphase-flow model is used to determine a most-probable minimum kill rate.

Accurate modeling of the hose instability in plasma wakefield accelerators

NASA Astrophysics Data System (ADS)

Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.; Martinez de la Ossa, A.; Osterhoff, J.; Esarey, E.; Leemans, W. P.

2018-05-01

Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. It paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

Oil Biodegradation and Oil-Degrading Microbial Populations in Marsh Sediments Impacted by Oil from the Deepwater Horizon Well Blowout.

PubMed

Atlas, Ronald M; Stoeckel, Donald M; Faith, Seth A; Minard-Smith, Angela; Thorn, Jonathan R; Benotti, Mark J

2015-07-21

To study hydrocarbon biodegradation in marsh sediments impacted by Macondo oil from the Deepwater Horizon well blowout, we collected sediment cores 18-36 months after the accident at the marshes in Bay Jimmy (Upper Barataria Bay), Louisiana, United States. The highest concentrations of oil were found in the top 2 cm of sediment nearest the waterline at the shorelines known to have been heavily oiled. Although petroleum hydrocarbons were detectable, Macondo oil could not be identified below 8 cm in 19 of the 20 surveyed sites. At the one site where oil was detected below 8 cm, concentrations were low. Residual Macondo oil was already highly weathered at the start of the study, and the concentrations of individual saturated hydrocarbons and polycyclic aromatic hydrocarbons continued to decrease over the course of the study due to biodegradation. Desulfococcus oleovorans, Marinobacter hydrocarbonoclasticus, Mycobacterium vanbaalenii, and related mycobacteria were the most abundant oil-degrading microorganisms detected in the top 2 cm at the oiled sites. Relative populations of these taxa declined as oil concentrations declined. The diversity of the microbial community was low at heavily oiled sites compared to that of the unoiled reference sites. As oil concentrations decreased over time, microbial diversity increased and approached the diversity levels of the reference sites. These trends show that the oil continues to be biodegraded, and microbial diversity continues to increase, indicating ongoing overall ecological recovery.

Footprint of Deepwater Horizon blowout impact to deep-water coral communities

PubMed Central

Fisher, Charles R.; Hsing, Pen-Yuan; Kaiser, Carl L.; Yoerger, Dana R.; Roberts, Harry H.; Shedd, William W.; Cordes, Erik E.; Shank, Timothy M.; Berlet, Samantha P.; Saunders, Miles G.; Larcom, Elizabeth A.; Brooks, James M.

2014-01-01

On April 20, 2010, the Deepwater Horizon (DWH) blowout occurred, releasing more oil than any accidental spill in history. Oil release continued for 87 d and much of the oil and gas remained in, or returned to, the deep sea. A coral community significantly impacted by the spill was discovered in late 2010 at 1,370 m depth. Here we describe the discovery of five previously unknown coral communities near the Macondo wellhead and show that at least two additional coral communities were impacted by the spill. Although the oil-containing flocullent material that was present on corals when the first impacted community was discovered was largely gone, a characteristic patchy covering of hydrozoans on dead portions of the skeleton allowed recognition of impacted colonies at the more recently discovered sites. One of these communities was 6 km south of the Macondo wellhead and over 90% of the corals present showed the characteristic signs of recent impact. The other community, 22 km southeast of the wellhead between 1,850 and 1,950 m depth, was more lightly impacted. However, the discovery of this site considerably extends the distance from Macondo and depth range of significant impact to benthic macrofaunal communities. We also show that most known deep-water coral communities in the Gulf of Mexico do not appear to have been acutely impacted by the spill, although two of the newly discovered communities near the wellhead apparently not impacted by the spill have been impacted by deep-sea fishing operations. PMID:25071200

TRIGGER OF A BLOWOUT JET IN A SOLAR CORONAL MASS EJECTION ASSOCIATED WITH A FLARE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Xiaohong; Yang, Shuhong; Chen, Huadong

2015-11-20

Using the multi-wavelength images and the photospheric magnetograms from the Solar Dynamics Observatory, we study the flare that was associated with the only coronal mass ejection (CME) in active region (AR) 12192. The eruption of a filament caused a blowout jet, and then an M4.0 class flare occurred. This flare was located at the edge of the AR instead of in the core region. The flare was close to the apparently “open” fields, appearing as extreme-ultraviolet structures that fan out rapidly. Due to the interaction between flare materials and “open” fields, the flare became an eruptive flare, leading to themore » CME. Then, at the same site of the first eruption, another small filament erupted. With the high spatial and temporal resolution Hα data from the New Vacuum Solar Telescope at the Fuxian Solar Observatory, we investigate the interaction between the second filament and the nearby “open” lines. The filament reconnected with the “open” lines, forming a new system. To our knowledge, the detailed process of this kind of interaction is reported for the first time. Then the new system rotated due to the untwisting motion of the filament, implying that the twist was transferred from the closed filament system to the “open” system. In addition, the twist seemed to propagate from the lower atmosphere to the upper layers and was eventually spread by the CME to the interplanetary space.« less

Calculation of Blowout Gun Nozzle Temperatures

DTIC Science & Technology

1981-07-01

rt u <u p- a Tto> tocNTj- t^f^o a>t-^oo MOtr^ vOi-i (NtOt/J L/JOOO sOLOr -- t^vOOO "*L0 \\or^QO vot^o invot^ uosor-> O ir^ O ’ o oo O 00 f...Cmd 28150 Dequindre Road Warren, MI 48090 Project Manager Cannon Artillery Wpns Systems ATTN: DRCPM-CAWS US Army ARRADCOM Dover, NJ 07801...Director US Army TRADOC Systems Analysis Activity ATTN: ATAA-SL, Tech Lib White Sands Missile Range, NM 88002 Organization No. of Copies 1

Preliminary Transient Performance Data on the J73 Turbojet Engine. 3; Altitude, 45,000 Feet

NASA Technical Reports Server (NTRS)

McAulay, John E.; Wallner, Lewis E.

1953-01-01

A program was undertaken to determine the J73 turbojet engine compressor stall and surge characteristics and combustor blow-out limits enc ountered during transient engine operation. Data were obtained in the form of oscillograph traces showing the time history of several engi ne parameters with changes in engine fuel flow. The data presented in this report are for step and ramp changes in fuel flow at an altitude of 45,000 feet and flight Mach numbers of 0 and 0.8.

Electron self-injection and trapping into an evolving plasma bubble.

PubMed

Kalmykov, S; Yi, S A; Khudik, V; Shvets, G

2009-09-25

The blowout (or bubble) regime of laser wakefield acceleration is promising for generating monochromatic high-energy electron beams out of low-density plasmas. It is shown analytically and by particle-in-cell simulations that self-injection of the background plasma electrons into the quasistatic plasma bubble can be caused by slow temporal expansion of the bubble. Sufficient criteria for the electron trapping and bubble's expansion rate are derived using a semianalytic nonstationary Hamiltonian theory. It is further shown that the combination of bubble's expansion and contraction results in monoenergetic electron beams.

Accurate modeling of the hose instability in plasma wakefield accelerators

DOE PAGES

Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.; ...

2018-05-20

Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. Lastly, it paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

Aircraft accident report: NASA 712, Convair 990, N712NA, March Air Force Base, California, July 17, 1985, executive summary

NASA Technical Reports Server (NTRS)

Batthauer, Byron E.; Mccarthy, G. T.; Hannah, Michael; Hogan, Robert J.; Marlow, Frank J.; Reynard, William D.; Stoklosa, Janis H.; Yager, Thomas J.

1986-01-01

On July 17, l985, NASA 712, a Convair 990 aircraft, was destroyed by fire during an aborted takeoff at March Air Force Base in California. Material ejected from a blowout in the tires of the right main landing gear penetrated the right-wing fuel tank. The leaking fuel ignited. Fire engulfed the right wing and fuselage as the aircraft stopped its forward motion. The crew of four and the 15 scientists and technicians aboard escaped without serious injury.

Accurate modeling of the hose instability in plasma wakefield accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehrling, T. J.; Benedetti, C.; Schroeder, C. B.

Hosing is a major challenge for the applicability of plasma wakefield accelerators and its modeling is therefore of fundamental importance to facilitate future stable and compact plasma-based particle accelerators. In this contribution, we present a new model for the evolution of the plasma centroid, which enables the accurate investigation of the hose instability in the nonlinear blowout regime. Lastly, it paves the road for more precise and comprehensive studies of hosing, e.g., with drive and witness beams, which were not possible with previous models.

Observational and Model Analysis of a Two-ribbon Flare Possibly Induced by a Neighboring Blowout Jet

NASA Astrophysics Data System (ADS)

Joshi, Bhuwan; Thalmann, Julia K.; Mitra, Prabir K.; Chandra, Ramesh; Veronig, Astrid M.

2017-12-01

In this paper, we present unique observations of a blowout coronal jet that possibly triggered a two-ribbon confined C1.2 flare in bipolar solar active region NOAA 12615 on 2016 December 5. The jet activity initiates at chromospheric/transition region heights with a small brightening that eventually increases in volume, with well-developed standard morphological jet features, viz., base and spire. The spire widens up with a collimated eruption of cool and hot plasma components, observed in the 304 and 94 Å channels of AIA, respectively. The speed of the plasma ejection, which forms the jet’s spire, was higher for the hot component (˜200 km s-1) than the cooler one (˜130 km s-1). The NLFF model of coronal fields at the pre- and post-jet phases successfully reveals openings of previously closed magnetic field lines with a rather inclined/low-lying jet structure. The peak phase of the jet emission is followed by the development of a two-ribbon flare that shows coronal loop emission in HXRs up to ˜25 keV energy. The coronal magnetic fields rooted at the location of EUV flare ribbons, derived from the NLFF model, demonstrate the pre-flare phase to exhibit an “X-type” configuration, while the magnetic fields at the post-flare phase are more or less oriented parallel. Comparisons of multi-wavelength measurements with the magnetic field extrapolations suggest that the jet activity likely triggered the two-ribbon flare by perturbing the field in the interior of the active region.

Orbital cellulitis: a rare complication after orbital blowout fracture.

PubMed

Ben Simon, Guy J; Bush, Steven; Selva, Dinesh; McNab, Alan A

2005-11-01

To report the incidence of orbital cellulitis after orbital blowout fracture. Retrospective, noncomparative, interventional case series. All patients with orbital cellulitis and a history of recent orbital fracture. A medical record review of clinical history, imaging studies, and surgical and treatment outcome was performed. Resolution of orbital cellulitis and surgical and imaging findings. Four patients (3 male; mean age, 30 years [range, 4.5-58]) were treated for orbital cellulitis complicating orbital fracture. All patients had evidence of paranasal sinusitis before or after the orbital injury, and 2 also reported forceful nose blowing after sustaining orbital trauma. Although 3 patients received prophylactic oral antibiotics after the fracture, this failed to prevent infection. Sinusitis commenced 1 to 2 weeks before and as late as 5 weeks after orbital injury. All patients were treated with IV antibiotics. Two developed an orbital abscess that required surgical drainage; 1 patient improved after an endonasal maxillary antrostomy. One patient improved on IV antibiotics alone and underwent fracture repair at a later stage. These 4 patients represent 0.8% of all cases of orbital fractures treated in the study period. Orbital cellulitis is a rare complication of orbital fracture, and seems to be more common when paranasal sinus infection preexists or occurs within several weeks of the injury. Oral antibiotics given after the orbital injury may not prevent orbital cellulitis or abscess formation. Surgery may be required to drain orbital abscess or in nonresolving cellulitis to drain the paranasal sinuses. Fracture repair, if indicated, should be delayed, particularly if an alloplastic implant is used.

Review of flow rate estimates of the Deepwater Horizon oil spill.

PubMed

McNutt, Marcia K; Camilli, Rich; Crone, Timothy J; Guthrie, George D; Hsieh, Paul A; Ryerson, Thomas B; Savas, Omer; Shaffer, Frank

2012-12-11

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ∼50,000-70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ∼5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.

Carbon Composition of Particulate Organic Carbon in the Gulf of Mexico

NASA Astrophysics Data System (ADS)

Rogers, K.; Montoya, J. P.; Weber, S.; Bosman, S.; Chanton, J.

2016-02-01

The Deepwater Horizon blowout released 5.0x1011 g C from gaseous hydrocarbons and up to 6.0x1011g C from oil into the water column. Another carbon source, adding daily to the water column, leaks from the natural hydrocarbon seeps that pepper the seafloor of the Gulf of Mexico. How much of this carbon from the DWH and natural seeps is assimilated into particulate organic carbon (POC) in the water column? We filtered seawater collected in 2010, 2012, and 2013 from seep and non-seep sites, collecting POC on 0.7µm glass microfiber filters and analyzing the POC for stable and radiocarbon isotopes. Mixing models based on carbon isotopic endmembers of methane, oil, and modern production were used to estimate the percentage of hydrocarbon incorporated into POC. Significant differences were seen between POC from shallow and deep waters and between POC collected from seep, non-seep, and blowout sites; however yearly differences were not as evident suggesting the GOM has a consistent supply of depleted carbon. Stable carbon isotopes signatures of POC in the Gulf averaged -23.7±2.5‰ for shallow samples and -26.65±2.9‰ for deep POC samples, while radiocarbon signatures averaged -100.4±146.1‰ for shallow and -394.6±197‰ for deep samples. POC in the northern Gulf are composed of 23-91% modern carbon, 2-21% methane, and 0-71% oil. Oil plays a major role in the POC composition of the GOM, especially at the natural seep GC600.

Intrusion dynamics of particle plumes in stratified water with weak crossflow: Application to deep ocean blowouts

NASA Astrophysics Data System (ADS)

Wang, Dayang; Adams, E. Eric

2016-06-01

We present an experimental study of particle plumes in ambient stratification and a mild current. In an inverted framework, the results describe the fate of oil droplets released from a deep ocean blowout. A continuous stream of dense glass beads was released from a carriage towed in a salt-stratified tank. Nondimensional particle slip velocity UN ranged from 0.1 to 1.9, and particles with UN ≤ 0.5 were observed to enter the intrusion layer. The spatial distributions of beads, collected on a bottom sled towed with the source, present a Gaussian distribution in the transverse direction and a skewed distribution in the along-current direction. Dimensions of the distributions increase with decreasing UN. The spreading relations can be used as input to far-field models describing subsequent transport of particles or, in an inverted framework, oil droplets. The average particle settling velocity, Uave, was found to exceed the individual particle slip velocity, Us, which is attributed to the initial plume velocity near the point of release. Additionally, smaller particles exhibit a "group" or "secondary plume" effect as they exit the intrusion as a swarm. The secondary effect becomes more prominent as UN decreases, and might help explain observations from the 2000 Deep Spill field experiment where oil was found to surface more rapidly than predicted based on Us. An analytical model predicting the particle deposition patterns was validated against experimental measurements, and used to estimate near-field oil transport under the Deepwater Horizon spill conditions, with/without chemical dispersants.

Review of flow rate estimates of the Deepwater Horizon oil spill

USGS Publications Warehouse

McNutt, Marcia K.; Camilli, Rich; Crone, Timothy J.; Guthrie, George D.; Hsieh, Paul A.; Ryerson, Thomas B.; Savas, Omer; Shaffer, Frank

2012-01-01

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ~50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ~5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly.

Review of flow rate estimates of the Deepwater Horizon oil spill

PubMed Central

McNutt, Marcia K.; Camilli, Rich; Crone, Timothy J.; Guthrie, George D.; Hsieh, Paul A.; Ryerson, Thomas B.; Savas, Omer; Shaffer, Frank

2012-01-01

The unprecedented nature of the Deepwater Horizon oil spill required the application of research methods to estimate the rate at which oil was escaping from the well in the deep sea, its disposition after it entered the ocean, and total reservoir depletion. Here, we review what advances were made in scientific understanding of quantification of flow rates during deep sea oil well blowouts. We assess the degree to which a consensus was reached on the flow rate of the well by comparing in situ observations of the leaking well with a time-dependent flow rate model derived from pressure readings taken after the Macondo well was shut in for the well integrity test. Model simulations also proved valuable for predicting the effect of partial deployment of the blowout preventer rams on flow rate. Taken together, the scientific analyses support flow rates in the range of ∼50,000–70,000 barrels/d, perhaps modestly decreasing over the duration of the oil spill, for a total release of ∼5.0 million barrels of oil, not accounting for BP's collection effort. By quantifying the amount of oil at different locations (wellhead, ocean surface, and atmosphere), we conclude that just over 2 million barrels of oil (after accounting for containment) and all of the released methane remained in the deep sea. By better understanding the fate of the hydrocarbons, the total discharge can be partitioned into separate components that pose threats to deep sea vs. coastal ecosystems, allowing responders in future events to scale their actions accordingly. PMID:22187459

Effects of fuel nozzle design on performance of an experimental annular combustor using natural gas fuel

NASA Technical Reports Server (NTRS)

Wear, J. D.; Schultz, D. F.

1972-01-01

Tests of various fuel nozzles were conducted with natural gas fuel in a full-annulus combustor. The nozzles were designed to provide either axial, angled, or radial fuel injection. Each fuel nozzle was evaluated by measuring combustion efficiency at relatively severe combustor operating conditions. Combustor blowout and altitude ignition tests were also used to evaluate nozzle designs. Results indicate that angled injection gave higher combustion efficiency, less tendency toward combustion instability, and altitude relight characteristics equal to or superior to those of the other fuel nozzles that were tested.

Efficiency Versus Instability in Plasma Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lebedev, Valeri; Burov, Alexey; Nagaitsev, Sergei

2017-01-05

Plasma wake-field acceleration in a strongly nonlinear (a.k.a. the blowout) regime is one of the main candidates for future high-energy colliders. For this case, we derive a universal efficiency-instability relation, between the power efficiency and the key instability parameter of the witness bunch. We also show that in order to stabilize the witness bunch in a regime with high power efficiency, the bunch needs to have high energy spread, which is not presently compatible with collider-quality beam properties. It is unclear how such limitations could be overcome for high-luminosity linear colliders.

Survived ileocecal blowout from compressed air.

PubMed

Weber, Marco; Kolbus, Frank; Dressler, Jan; Lessig, Rüdiger

2011-03-01

Industrial accidents with compressed air entering the gastro-intestinal tract often run fatally. The pressures usually over-exceed those used by medical applications such as colonoscopy and lead to vast injuries of the intestines with high mortality. The case described in this report is of a 26-year-old man who was harmed by compressed air that entered through the anus. He survived because of fast emergency operation. This case underlines necessity of explicit instruction considering hazards handling compressed air devices to maintain safety at work. Further, our observations support the hypothesis that the mucosa is the most elastic layer of the intestine wall.

An Experimental Study of the Ionization of Low-Density Gas Flows by Induced Discharges

NASA Technical Reports Server (NTRS)

Barger, R. L.; Brooks, J. D.; Beasley, W. D.

1960-01-01

Induced discharges are advantageous for ionizing low-density flows in that they introduce no electrode contamination into the flow and they provide a relatively high degree of ionization with good coupling of power into the gas. In this investigation a 40-megacycle oscillator was used to produce and maintain induced discharges in argon and mercury-vapor flows. Methods for preventing blowout of the discharge were determined, and power measurements were made with an in-line wattmeter. Some results with damped oscillations pulsed at 1,000 pulses per second are also presented.

Chemical and Physical Properties of Hi-Cal-2

NASA Technical Reports Server (NTRS)

Spakowski, A. E.; Allen, Harrison, Jr.; Caves, Robert M.

1955-01-01

As part of the Navy Project Zip to consider various boron-containing materials as possible high-energy fuels, the chemical and physical properties of Hi-Cal-2 prepared by the Callery Chemical Company were evaluated at the NACA Lewis laboratory. Elemental chemical analysis, heat of combustion, vapor pressure and decomposition, freezing point, density, self ignition temperature, flash point, and blow-out velocity were determined for the fuel. Although the precision of measurement of these properties was not equal to that obtained for hydrocarbons, this special release research memorandum was prepared to make the data available as soon as possible.

Polydisperse effects in jet spray flames

NASA Astrophysics Data System (ADS)

Weinberg, Noam; Greenberg, J. Barry

2018-01-01

A laminar jet polydisperse spray diffusion flame is analysed mathematically for the first time using an extension of classical similarity solutions for gaseous jet flames. The analysis enables a comparison to be drawn between conditions for flame stability or flame blow-out for purely gaseous flames and for spray flames. It is found that, in contrast to the Schmidt number criteria relevant to gas flames, droplet size and initial spray polydispersity play a critical role in determining potential flame scenarios. Some qualitative agreement for lift-off height is found when comparing predictions of the theory and sparse independent experimental evidence from the literature.

The Gulf of Mexico Research Initiative: Managing a Multidisciplinary Data Explosion

NASA Astrophysics Data System (ADS)

Howard, M. K.; Gibeaut, J. C.; Reed, D.

2011-12-01

On April 20, 2010 the Deepwater Horizon drilling unit located in the northeastern Gulf of Mexico, experienced a catastrophic wellhead blowout. Roughly 5 billion barrels of oil and 1 million U.S. gallons of dispersant were released near the wellhead over the next three months. Within weeks of the blowout, BP announced the Gulf of Mexico Research Initiative (GRI) and pledged 50M/yr over 10 years for independent scientific research on the spill's impact on the ecosystem. Two months after the blowout three institutions were awarded a total of 25M in fast-track grants (Louisiana State University, Northern Gulf Institute, and Florida Institute of Oceanography). Soon after the Alabama Marine Environmental Sciences Consortium and the National Institutes of Health were awarded 5M and 10M, respectively. These five institutions began to generate data almost immediately. First year grants funded 100's of researchers from nearly 100 research units. Their activities included numerical modeling, field data collection, and laboratory experiments. Measured parameters included those associated with chemical analyses of oil, gas, and dispersants, studies of bacteria, plants and animals -from phytoplankton to marsh grasses, from zooplankton to cetaceans. Studies were conducted from estuaries to the deep Gulf, from atmosphere to sediments. Parameters from physical oceanography, marine meteorology, and biogeochemistry were measured in abundance. Additionally, impact studies on human mental, physical health and businesses were made. Proposals for years 2-4 of the program were to be awarded in August 2011 supporting 4-8 research consortia. Consortia may have up to 20 named researchers. In aggregate, these studies yielded a multidisciplinary data explosion. Following the fast-track awards the GRI Administrative Unit (AU) was established and a data management activity initiated. That activity became the GRI Information and Data Cooperative (GRIIDC). "Cooperative" emphasizes the collaborative relationship GRIIDC needed with the data originators. GRI founders only required that the AU provide a research database and data be shared openly with a minimum of delay and archived at national repositories. GRIIDC has three functions, to manage the data in cooperation with the originators, to facilitate public access to the data through the research database and to support management's need to track the project's progress. GRIIDC needed to rapidly assess the volume of data and specific parameters being collected, to quickly hire information technology and subject matter experts, to establish data policies for reporting, metadata content, submittal form and formats, and to establish and maintain mutually agreeable divisions of labor with the data originators. This presentation will describe the challenges and lessons learned by GRIIDC while building a collaborative end-to-end data management system designed to absorb, organize, share, and curate the massively heterogeneous data set produced by nearly $200M of GRI research.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Morales, F. Y.; Bryden, G.; Werner, M. W.

We present dual-band Herschel /PACS imaging for 59 main-sequence stars with known warm dust ( T {sub warm} ∼ 200 K), characterized by Spitzer . Of 57 debris disks detected at Herschel wavelengths (70 and/or 100 and 160 μ m), about half have spectral energy distributions (SEDs) that suggest two-ring disk architectures mirroring that of the asteroid–Kuiper Belt geometry; the rest are consistent with single belts of warm, asteroidal material. Herschel observations spatially resolve the outer/cold dust component around 14 A-type and 4 solar-type stars with two-belt systems, 15 of which for the first time. Resolved disks are typically observedmore » with radii >100 AU, larger than expected from a simple blackbody fit. Despite the absence of narrow spectral features for ice, we find that the shape of the continuum, combined with resolved outer/cold dust locations, can help constrain the grain size distribution and hint at the dust’s composition for each resolved system. Based on the combined Spitzer /IRS+Multiband Imaging Photometer (5-to-70 μ m) and Herschel /PACS (70-to-160 μ m) data set, and under the assumption of idealized spherical grains, we find that over half of resolved outer/cold belts are best fit with a mixed ice/rock composition. Minimum grain sizes are most often equal to the expected radiative blowout limit, regardless of composition. Three of four resolved systems around the solar-type stars, however, tend to have larger minimum grains compared to expectation from blowout ( f {sub MB} = a {sub min}/ a {sub BOS} ∼ 5). We also probe the disk architecture of 39 Herschel -unresolved systems by modeling their SEDs uniformly, and find them to be consistent with 31 single- and 8 two-belt debris systems.« less

A review of seafood safety after the deepwater horizon blowout.

PubMed

Gohlke, Julia M; Doke, Dzigbodi; Tipre, Meghan; Leader, Mark; Fitzgerald, Timothy

2011-08-01

The Deepwater Horizon (DH) blowout resulted in fisheries closings across the Gulf of Mexico. Federal agencies, in collaboration with impacted Gulf states, developed a protocol to determine when it is safe to reopen fisheries based on sensory and chemical analyses of seafood. All federal waters have been reopened, yet concerns have been raised regarding the robustness of the protocol to identify all potential harmful exposures and protect the most sensitive populations. We aimed to assess this protocol based on comparisons with previous oil spills, published testing results, and current knowledge regarding chemicals released during the DH oil spill. We performed a comprehensive review of relevant scientific journal articles and government documents concerning seafood contamination and oil spills and consulted with academic and government experts. Protocols to evaluate seafood safety before reopening fisheries have relied on risk assessment of health impacts from polycyclic aromatic hydrocarbon (PAH) exposures, but metal contamination may also be a concern. Assumptions used to determine levels of concern (LOCs) after oil spills have not been consistent across risk assessments performed after oil spills. Chemical testing results after the DH oil spill suggest PAH levels are at or below levels reported after previous oil spills, and well below LOCs, even when more conservative parameters are used to estimate risk. We recommend use of a range of plausible risk parameters to set bounds around LOCs, comparisons of post-spill measurements with baseline levels, and the development and implementation of long-term monitoring strategies for metals as well as PAHs and dispersant components. In addition, the methods, results, and uncertainties associated with estimating seafood safety after oil spills should be communicated in a transparent and timely manner, and stakeholders should be actively involved in developing a long-term monitoring strategy.

Endoscopic transnasal approach for the treatment of isolated medial orbital blow-out fractures: a prospective study of preoperative and postoperative orbital volume change.

PubMed

Kim, KyoungHoon; Song, KyeongHo; Choi, SooJong; Bae, YongChan; Choi, ChiWon; Oh, HeungChan; Lee, JaeWoo; Nam, SuBong

2012-02-01

Endoscopic transnasal reduction is a safe and effective technique for the treatment of blow-out fractures of the medial orbital wall. However, because this approach does not use rigid permanent material for reconstruction of the fractured medial orbital wall, some degree of herniation of the orbital contents may occur after the intraethmoidal packing material is removed. The purpose of this study was to evaluate the change in orbital volume in patients with medial orbital wall fractures treated through an endoscopic transnasal approach. This study was a prospective analysis that includes 20 patients who underwent endoscopic transnasal reduction of medial orbital wall fractures between April 2007 and December 2008. Computer-assisted orbital volume measurements were made using axial computed tomography. The mean (standard deviation [SD]) volume increase was 2.00 (0.92) cm(3) and the mean (SD) dimension of the fractured orbital wall was 2.76 (0.83) cm(2). After endoscopic surgery, an average (SD) volume decrease of 2.15 (0.91) cm(3) was achieved with ethmoid sinus packing. After removal of the packing materials, 1.14 (0.78) cm(3) increase of the orbital volume was observed. The dimension of the orbital wall fracture significantly correlated with the increased preoperative orbital volume (P = 0.002, r = 0.609); the preoperative increase in the orbital volume also significantly correlated with volume relapse after removal of the packing (P = 0.023, r = 0.452). These findings suggest that in broad orbital wall fractures, reconstruction of the orbital wall by rigid materials or prolongation of the packing period should be considered, because orbital volume can increase again after packing removal, and may thus lead to postoperative complications.

Theory and measurements of emittance preservation in plasma wakefield acceleration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Frederico, Joel

2016-12-01

In this dissertation, we examine the preservation and measurement of emittance in the plasma wakefield acceleration blowout regime. Plasma wakefield acceleration (PWFA) is a revolutionary approach to accelerating charged particles that has been demonstrated to have the potential for gradients orders of magnitude greater than traditional approaches. The application of PWFA to the design of a linear collider will make new high energy physics research possible, but the design parameters must first be shown to be competitive with traditional methods. Emittance preservation is necessary in the design of a linear collider in order to maximize luminosity. We examine the conditionsmore » necessary for circular symmetry in the PWFA blowout regime, and demonstrate that current proposals meet these bounds. We also present an application of beam lamentation which describes the process of beam parameter and emittance matching. We show that the emittance growth saturates as a consequence of energy spread in the beam. The initial beam parameters determine the amount of emittance growth, while the contribution of energy spread is negligible. We also present a model for ion motion in the presence of a beam that is much more dense than the plasma. By combining the model of ion motion and emittance growth, we find the emittance growth due to ion motion is minimal in the case of marginal ion motion. In addition, we present a simulation that validates the ion motion model, which is under further development to examine emittance growth of both marginal and pronounced ion motion. Finally, we present a proof-of-concept of an emittance measurement which may enable the analysis of emittance preservation in future PWFA experiments.« less

Dark-matter haloes and the M-σ relation for supermassive black holes

NASA Astrophysics Data System (ADS)

Larkin, Adam C.; McLaughlin, Dean E.

2016-10-01

We develop models of two-component spherical galaxies to establish scaling relations linking the properties of spheroids at z = 0 (total stellar masses, effective radii Re and velocity dispersions within Re) to the properties of their dark-matter haloes at both z = 0 and higher redshifts. Our main motivation is the widely accepted idea that the accretion-driven growth of supermassive black holes (SMBHs) in protogalaxies is limited by quasar-mode feedback and gas blow-out. The SMBH masses, MBH, should then be connected to the dark-matter potential wells at the redshift zqso of the blow-out. We specifically consider the example of a power-law dependence on the maximum circular speed in a protogalactic dark-matter halo: M_{BH}∝ V^4_{d,pk}, as could be expected if quasar-mode feedback were momentum-driven. For haloes with a given Vd,pk at a given zqso ≥ 0, our model scaling relations give a typical stellar velocity dispersion σap(Re) at z = 0. Thus, they transform a theoretical MBH-Vd,pk relation into a prediction for an observable MBH-σap(Re) relation. We find the latter to be distinctly non-linear in log-log space. Its shape depends on the generic redshift evolution of haloes in a Λ cold dark matter cosmology and the systematic variation of stellar-to-dark matter mass fraction at z = 0, in addition to any assumptions about the physics underlying the MBH-Vd,pk relation. Despite some clear limitations of the form we use for MBH versus Vd,pk, and even though we do not include any SMBH growth through dry mergers at low redshift, our results for MBH-σap(Re) compare well to data for local early types if we take zqso ˜ 2-4.

Approach for assessing coastal vulnerability to oil spills for prevention and readiness using GIS and the Blowout and Spill Occurrence Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nelson, J. R.; Grubesic, T. H.; Sim, L.

Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associated with exploration efforts further offshore into deeper waters and more uncertain subsurface settings. This has become particularly common in the U.S. Gulf of Mexico. In this study we develop a spatial vulnerability approach and example assessment to support future spill prevention and improve future response readiness. This effort, which is part of a larger integrated assessment modeling spill prevention effort, incorporated economic and environmental data, and utilized a novel new oil spill simulation model from the U.S. Department of Energy’s National Energy Technology Laboratory, the Blowout and Spillmore » Occurrence Model (BLOSOM). Specifically, this study demonstrated a novel approach to evaluate potential impacts of hypothetical spill simulations at varying depths and locations in the northern Gulf of Mexico. The simulations are analyzed to assess spatial and temporal trends associated with the oil spill. The approach itself demonstrates how these data, tools and techniques can be used to evaluate potential spatial vulnerability of Gulf communities for various spill scenarios. Results of the hypothetical scenarios evaluated in this study suggest that under conditions like those simulated, a strong westward push by ocean currents and tides may increase the impacts of deep water spills along the Texas coastline, amplifying the vulnerability of communities on the local barrier islands. Ultimately, this approach can be used further to assess a range of conditions and scenarios to better understand potential risks and improve informed decision making for operators, responders, and stakeholders to support spill prevention as well as response readiness.« less

Securing the appendiceal stump with the Gea extracorporeal sliding knot during laparoscopic appendectomy is safe and economical.

PubMed

Arcovedo, R; Barrera, H; Reyes, H S

2007-10-01

Laparoscopic appendectomy (LA) has become very popular. One criticism of this approach is the high cost of the disposable equipment such as the linear stapler. An alternative would be suture ligation of the appendiceal base. To prove the safety of the Gea extracorporeal sliding knot (GESK) for closure of the stump after LA, a retrospective study was conducted. For this study, 63 LA procedures performed by one surgeon using the Gea knot (group A) were reviewed and compared with 63 LA procedures performed by two other surgeons (group B) using the linear stapler. The GESK is created with 0-prolene in the manner already described. The main variable was the presence or absence of blowout, leak, or fistula from the appendiceal stump. The secondary variables were abdominal abscess, wound infection, and need for readmission or reoperation. The results were analyzed using the appropriate statistical methods. Both groups were similar in terms of age, gender, and pathologic diagnosis. No patient in group A or B experienced a colonic fistula, stump blowout, or leak. In group A, one patient experienced interloop abscesses. There were two wound infections. In group B, one patient experienced a wound infection, and another patient had a wound dehiscence of the umbilical port, which required reoperation. No statistical differences were noted between the two groups. There are surgeons who routinely use sutures to secure the stump of the appendectomy. This study aimed to demonstrate that the GESK is as secure as the stapler for closure of the appendiceal stump. The GESK could be passed through a 5-mm trocar, potentially avoiding complications of a larger trocar site. The GESK seems to be an economic and safe alternative to the stapler.

Observations of quasi-periodic phenomena associated with a large blowout solar jet

NASA Astrophysics Data System (ADS)

Morton, R. J.; Srivastava, A. K.; Erdélyi, R.

2012-06-01

Aims: A variety of periodic phenomena have been observed in conjunction with large solar jets. We aim to find further evidence for (quasi-)periodic behaviour in solar jets and determine what the periodic behaviour can tell us about the excitation mechanism and formation process of the large solar jet. Methods: Using the 304 Å (He-II), 171 Å (Fe IX), 193 Å (Fe XII/XXIV) and 131 Å (Fe VIII/XXI) filters onboard the Solar Dynamic Observatory (SDO) Atmospheric Imaging Assembly (AIA), we investigate the intensity oscillations associated with a solar jet. Results: Evidence is provided for multiple magnetic reconnection events occurring between a pre-twisted, closed field and open field lines. Components of the jet are seen in multiple SDO/AIA filters covering a wide range of temperatures, suggesting the jet can be classified as a blowout jet. Two bright, elongated features are observed to be co-spatial with the large jet, appearing at the jet's footpoints. Investigation of these features reveal they are defined by multiple plasma ejections. The ejecta display (quasi-)periodic behaviour on timescales of 50 s and have rise velocities of 40-150 km s-1 along the open field lines. Due to the suggestion that the large jet is reconnection-driven and the observed properties of the ejecta, we further propose that these ejecta events are similar to type-II spicules. The bright features also display (quasi)-periodic intensity perturbations on the timescale of 300 s. Possible explanations for the existence of the (quasi-)periodic perturbations in terms of jet dynamics and the response of the transition region are discussed. Movies are available in electronic form at http://www.aanda.org

Computationally efficient methods for modelling laser wakefield acceleration in the blowout regime

NASA Astrophysics Data System (ADS)

Cowan, B. M.; Kalmykov, S. Y.; Beck, A.; Davoine, X.; Bunkers, K.; Lifschitz, A. F.; Lefebvre, E.; Bruhwiler, D. L.; Shadwick, B. A.; Umstadter, D. P.; Umstadter

2012-08-01

Electron self-injection and acceleration until dephasing in the blowout regime is studied for a set of initial conditions typical of recent experiments with 100-terawatt-class lasers. Two different approaches to computationally efficient, fully explicit, 3D particle-in-cell modelling are examined. First, the Cartesian code vorpal (Nieter, C. and Cary, J. R. 2004 VORPAL: a versatile plasma simulation code. J. Comput. Phys. 196, 538) using a perfect-dispersion electromagnetic solver precisely describes the laser pulse and bubble dynamics, taking advantage of coarser resolution in the propagation direction, with a proportionally larger time step. Using third-order splines for macroparticles helps suppress the sampling noise while keeping the usage of computational resources modest. The second way to reduce the simulation load is using reduced-geometry codes. In our case, the quasi-cylindrical code calder-circ (Lifschitz, A. F. et al. 2009 Particle-in-cell modelling of laser-plasma interaction using Fourier decomposition. J. Comput. Phys. 228(5), 1803-1814) uses decomposition of fields and currents into a set of poloidal modes, while the macroparticles move in the Cartesian 3D space. Cylindrical symmetry of the interaction allows using just two modes, reducing the computational load to roughly that of a planar Cartesian simulation while preserving the 3D nature of the interaction. This significant economy of resources allows using fine resolution in the direction of propagation and a small time step, making numerical dispersion vanishingly small, together with a large number of particles per cell, enabling good particle statistics. Quantitative agreement of two simulations indicates that these are free of numerical artefacts. Both approaches thus retrieve the physically correct evolution of the plasma bubble, recovering the intrinsic connection of electron self-injection to the nonlinear optical evolution of the driver.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Micheva, Genoveva; Oey, M. S.; Jaskot, Anne E.

We present the remarkable discovery that the dwarf irregular galaxy NGC 2366 is an excellent analog of the Green Pea (GP) galaxies, which are characterized by extremely high ionization parameters. The similarities are driven predominantly by the giant H ii region Markarian 71 (Mrk 71). We compare the system with GPs in terms of morphology, excitation properties, specific star-formation rate, kinematics, absorption of low-ionization species, reddening, and chemical abundance, and find consistencies throughout. Since extreme GPs are associated with both candidate and confirmed Lyman continuum (LyC) emitters, Mrk 71/NGC 2366 is thus also a good candidate for LyC escape. Themore » spatially resolved data for this object show a superbubble blowout generated by mechanical feedback from one of its two super star clusters (SSCs), Knot B, while the extreme ionization properties are driven by the ≲1 Myr-old, enshrouded SSC Knot A, which has ∼10 times higher ionizing luminosity. Very massive stars (>100 M {sub ⊙}) may be present in this remarkable object. Ionization-parameter mapping indicates that the blowout region is optically thin in the LyC, and the general properties also suggest LyC escape in the line of sight. Mrk 71/NGC 2366 does differ from GPs in that it is one to two orders of magnitude less luminous. The presence of this faint GP analog and candidate LyC emitter (LCE) so close to us suggests that LCEs may be numerous and commonplace, and therefore could significantly contribute to the cosmic ionizing budget. Mrk 71/NGC 2366 offers an unprecedentedly detailed look at the viscera of a candidate LCE, and could clarify the mechanisms of LyC escape.« less

Approach for assessing coastal vulnerability to oil spills for prevention and readiness using GIS and the Blowout and Spill Occurrence Model

DOE PAGES

Nelson, J. R.; Grubesic, T. H.; Sim, L.; ...

2015-08-01

Increasing interest in offshore hydrocarbon exploration has pushed the operational fronts associated with exploration efforts further offshore into deeper waters and more uncertain subsurface settings. This has become particularly common in the U.S. Gulf of Mexico. In this study we develop a spatial vulnerability approach and example assessment to support future spill prevention and improve future response readiness. This effort, which is part of a larger integrated assessment modeling spill prevention effort, incorporated economic and environmental data, and utilized a novel new oil spill simulation model from the U.S. Department of Energy’s National Energy Technology Laboratory, the Blowout and Spillmore » Occurrence Model (BLOSOM). Specifically, this study demonstrated a novel approach to evaluate potential impacts of hypothetical spill simulations at varying depths and locations in the northern Gulf of Mexico. The simulations are analyzed to assess spatial and temporal trends associated with the oil spill. The approach itself demonstrates how these data, tools and techniques can be used to evaluate potential spatial vulnerability of Gulf communities for various spill scenarios. Results of the hypothetical scenarios evaluated in this study suggest that under conditions like those simulated, a strong westward push by ocean currents and tides may increase the impacts of deep water spills along the Texas coastline, amplifying the vulnerability of communities on the local barrier islands. Ultimately, this approach can be used further to assess a range of conditions and scenarios to better understand potential risks and improve informed decision making for operators, responders, and stakeholders to support spill prevention as well as response readiness.« less

Pulse waveform analysis on temporal changes in ocular blood flow due to caffeine intake: a comparative study between habitual and non-habitual groups.

PubMed

Ismail, Aishah; Bhatti, Mehwish S; Faye, Ibrahima; Lu, Cheng Kai; Laude, Augustinus; Tang, Tong Boon

2018-06-06

To evaluate and compare the temporal changes in pulse waveform parameters of ocular blood flow (OBF) between non-habitual and habitual groups due to caffeine intake. This study was conducted on 19 healthy subjects (non-habitual 8; habitual 11), non-smoking and between 21 and 30 years of age. Using laser speckle flowgraphy (LSFG), three areas of optical nerve head were analyzed which are vessel, tissue, and overall, each with ten pulse waveform parameters, namely mean blur rate (MBR), fluctuation, skew, blowout score (BOS), blowout time (BOT), rising rate, falling rate, flow acceleration index (FAI), acceleration time index (ATI), and resistive index (RI). Two-way mixed ANOVA was used to determine the difference between every two groups where p < 0.05 is considered significant. There were significant differences between the two groups in several ocular pulse waveform parameters, namely MBR (overall, vessel, tissue), BOT (overall), rising rate (overall), and falling rate (vessel), all with p < 0.05. In addition, the ocular pulse waveform parameters, i.e., MBR (overall), skew (tissue), and BOT (tissue) showed significant temporal changes within the non-habitual group, but not within the habitual group. The temporal changes in parameters MBR (vessel, tissue), skew (overall, vessel), BOT (overall, vessel), rising rate (overall), falling rate (overall, vessel), and FAI (tissue) were significant for both groups (habitual and non-habitual) in response to caffeine intake. The experiment results demonstrated caffeine does modulate OBF significantly and response differently in non-habitual and habitual groups. Among all ten parameters, MBR and BOT were identified as the suitable biomarkers to differentiate between the two groups.

Method of producing complex aluminum alloy parts of high temper, and products thereof

NASA Technical Reports Server (NTRS)

Wilson, I. J. (Inventor)

1978-01-01

Fully annealed aluminum sheet is first stretch formed to the complex, doubly compound shape of a previously prepared forming die, e.g., an ejection seat blowout panel of a shuttlecraft. The part is then marked with a series of grid lines for monitoring later elongation. Thereafter it is solution heat treated and refrigerated to retard hardening. While still soft, it is stretched a second time on the same die to induce a modicum of work hardening, after which it is aged to the desired stress corrosion resistant temper, preferably the T8 level, to provide the desired hardness and stress corrosion resistance.

Implications of arcing due to spacecraft charging on spacecraft EMI margins of immunity

NASA Technical Reports Server (NTRS)

Inouye, G. T.

1981-01-01

Arcing due to spacecraft charging on spacecraft EMI margins of immunity was determined. The configuration of the P78-2 spacecraft of the SCATHA program was analyzed. A brushfire arc discharge model was developed, and a technique for initiating discharges with a spark plug trigger was for data configuration. A set of best estimate arc discharge parameters was defined. The effects of spacecraft potentials in limiting the discharge current blowout component are included. Arc discharge source models were incorporated into a SEMCAP EMI coupling analysis code for the DSP spacecraft. It is shown that with no mission critical circuits will be affected.

The effect of incomplete fuel-air mixing on the lean blowout limit, lean stability limit and NO(x) emissions in lean premixed gas turbine combustors

NASA Technical Reports Server (NTRS)

Shih, W.-P.; Lee, J. G.; Santavicca, D. A.

1994-01-01

Gas turbine engines for both land-based and aircraft propulsion applications are facing regulations on NOx emissions which cannot be met with current combustor technology. A number of alternative combustor strategies are being investigated which have the potential capability of achieving ultra-low NOx emissions, including lean premixed combustors, direct injection combustors, rich burn-quick quench-lean burn combustors and catalytic combustors. The research reported in this paper addresses the effect of incomplete fuel-air mixing on the lean limit performance and the NOx emissions characteristics of lean premixed combustors.

Communications systems and methods for subsea processors

DOEpatents

Gutierrez, Jose; Pereira, Luis

2016-04-26

A subsea processor may be located near the seabed of a drilling site and used to coordinate operations of underwater drilling components. The subsea processor may be enclosed in a single interchangeable unit that fits a receptor on an underwater drilling component, such as a blow-out preventer (BOP). The subsea processor may issue commands to control the BOP and receive measurements from sensors located throughout the BOP. A shared communications bus may interconnect the subsea processor and underwater components and the subsea processor and a surface or onshore network. The shared communications bus may be operated according to a time division multiple access (TDMA) scheme.

Development and application of the double V type flame stabilizer

NASA Astrophysics Data System (ADS)

Zhang, Hongbin; Wang, Jigen

1994-06-01

The double V type flame stabilizer is an advanced stabilizer of low drag constructed with a big V type stabilizer overlapping to a small V type one. It has the advantages of good ignition performance, low drag loss, improved afterburning efficiency, low skin temperature, and leaner blowout boundary, hence the overall performance of turbojet engine will be improved and the flight reliability increased. More than 40 tests on stand rig, 10 tests in aircraft and 8 tests in flight were carried out for its birth, and thereafter, it started to be in service for the turbojet engine on a small batch scale in 1986-1987.

Investigation of a nozzle instability on an F100 engine equipped with a digital electronic engine control

NASA Technical Reports Server (NTRS)

Burcham, F. W., Jr.; Zeller, J. R.

1984-01-01

An instability in the nozzle of the F100 engine, equipped with a digital electronic engine control (DEEC), was observed during a flight evaluation on an F-15 aircraft. The instability occurred in the upper left hand corner (ULMC) of the flight envelope during augmentation. The instability was not predicted by stability analysis, closed-loop simulations of the the engine, or altitude testing of the engine. The instability caused stalls and augmentor blowouts. The nozzle instability and the altitude testing are described. Linear analysis and nonlinear digital simulation test results are presented. Software modifications on further flight test are discussed.

Effect of flame-tube head structure on combustion chamber performance

NASA Technical Reports Server (NTRS)

Gu, Minqqi

1986-01-01

The experimental combustion performance of a premixed, pilot-type flame tube with various head structures is discussed. The test study covers an extensive area: efficiency of the combustion chamber, quality of the outlet temperature field, limit of the fuel-lean blowout, ignition performance at ground starting, and carbon deposition. As a result of these tests, a nozzle was found which fits the premixed pilot flame tube well. The use of this nozzle optimized the performance of the combustion chamber. The tested models had premixed pilot chambers with two types of air-film-cooling structures, six types of venturi-tube structures, and secondary fuel nozzles with two small spray-cone angles.

Performance gains by using heated natural-gas fuel in an annular turbojet combustor

NASA Technical Reports Server (NTRS)

Marchionna, N. R.

1973-01-01

A full-scale annular turbojet combustor was tested with natural gas fuel heated from ambient temperature to 800 K (980 F). In all tests, heating the fuel improved combustion efficiency. Two sets of gaseous fuel nozzles were tested. Combustion instabilities occurred with one set of nozzles at two conditions: one where the efficiency approached 100 percent with the heated fuel; the other where the efficiency was very poor with the unheated fuel. The second set of nozzles exhibited no combustion instability. Altitude relight tests with the second set showed that relight was improved and was achievable at essentially the same condition as blowout when the fuel temperature was 800 K (980 F).

Numerical Simulation And Experimental Investigation Of The Lift-Off And Blowout Of Enclosed Laminar Flames

NASA Technical Reports Server (NTRS)

Venuturmilli, Rajasekhar; Zhang, Yong; Chen, Lea-Der

2003-01-01

Enclosed flames are found in many industrial applications such as power plants, gas-turbine combustors and jet engine afterburners. A better understanding of the burner stability limits can lead to development of combustion systems that extend the lean and rich limits of combustor operations. This paper reports a fundamental study of the stability limits of co-flow laminar jet diffusion flames. A numerical study was conducted that used an adaptive mesh refinement scheme in the calculation. Experiments were conducted in two test rigs with two different fuels and diluted with three inert species. The numerical stability limits were compared with microgravity experimental data. Additional normal-gravity experimental results were also presented.

Turbojet Performance and Operation at High Altitudes with Hydrogen and Jp-4 Fuels

NASA Technical Reports Server (NTRS)

Fleming, W A; Kaufman, H R; Harp, J L , Jr; Chelko, L J

1956-01-01

Two current turbojet engines were operated with gaseous-hydrogen and JP-4 fuels at very high altitudes and a simulated Mach number of 0.8. With gaseous hydrogen as the fuel stable operation was obtained at altitudes up to the facility limit of about 90,000 feet and the specific fuel consumption was only 40 percent of that with JP-4 fuel. With JP-4 as the fuel combustion was unstable at altitudes above 60,000 to 65,000 feet and blowout limits were reached at 75,000 to 80,000 feet. Over-all performance, component efficiencies, and operating range were reduced considerable at very high altitudes with both fuels.

Challenges to oil spill assessment for seabirds in the deep ocean

USGS Publications Warehouse

Haney, J. Christopher; Jodice, Patrick G. R.; Montevecchi, William; Evers, David C.

2017-01-01

We synthesize impediments for evaluating effects to seabirds from open ocean hydrocarbon releases. Effects on seabirds from ship discharges, spills, and well blowouts often are poorly detected and monitored far from land. Regulatory regimes for ocean spills can result in monitoring efforts that are not entirely transparent. We illustrate how interdisciplinary technologies address deficits that hamper individual or population level assessments for seabirds, and we demonstrate where emerging technologies might be engaged to bridge gaps in oil spill monitoring. Although acute mortality from direct oil exposure poses the greatest risk to seabirds, other hazards from light-attraction, flaring, collisions, chronic pollution, and hydrocarbon inhalation around oil infrastructure also may induce bird mortality in the deep ocean.

Brush seals for cryogenic applications

NASA Astrophysics Data System (ADS)

Proctor, Margaret P.

1994-07-01

This viewgraph presentation presents test results of brush seals for cryogenic applications. Leakage for a single brush seal was two to three times less than for a 12-tooth labyrinth seal. The maximum temperature rise for a single brush seal was less than 50 R and occurred at 25 psid across the seal and 35,000 rpm. A static blowout test demonstrated sealing capability up to 550 psid. The seal limit was not obtained. The power loss for a single brush at 35,000 rpm and 175 psid was 2.45 hp. Two brushes far apart leak less than two brushes tight packed. Rotor wear was approximately 0.00075 mils and bristle wear was 1-3 mils after 4-1/2 hours.

Ixtoc oil spill assessment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boehm, P.

The blowout of the Ixtoc I oil well in the Bay of Campeche resulted in the largest documented spill in history. Approximately half a million metric tons of oil were released from June 3, 1979 to March 23, 1980. Of that amount, an estimated 11 thousand metric tons impacted south Texas beaches. As a result of the movement of oil from the Ixtoc I well blowout into the South Texas Outer Continental Shelf (STOCS) environment, a study was undertaken to establish the magnitude and areal extent of perturbation of the benthic community caused by chemical residues of Ixtoc oil. Themore » study focused on the inner shelf region to the 60-metre isobath and examined both the biology and hydrocarbon geochemistry of 12 sites coincident with those of four previously studied (1975-1977) baseline transects. Additionally, 26 sites within the region sampled during 1979 (mid-spill) for chemical parameters and again in 1980 (post-spill) for chemical and biological parameters, and 39 other sites sampled in 1979 for chemical parameters, were studied. The Burmah Agate oil tanker collided with the freighter Mimosa in November, 1979 5 miles off of Galveston, Texas and spilled part of its cargo of light crude oil. Approximately 21 thousand metric tons of the spilled oil burned in an ensuing fire. As the potentially complicating impact of the Burmah Agate tanker collision was of importance in the region, a set of six sites in the Galveston region were sampled to gain knowledge of the presence and nature of introduced chemical residues from this event. This study established a chemical and biological framework for carrying out spill assessment studies of this nature. It utilized a significant environmental data base for post-impact studies for the first time, and identified several sampling methodology deficiencies which, if corrected, may help to fine-tune such assessments.« less

Numerical and experimental analysis of factors leading to suture dehiscence after Billroth II gastric resection.

PubMed

Cvetkovic, Aleksandar M; Milasinovic, Danko Z; Peulic, Aleksandar S; Mijailovic, Nikola V; Filipovic, Nenad D; Zdravkovic, Nebojsa D

2014-11-01

The main goal of this study was to numerically quantify risk of duodenal stump blowout after Billroth II (BII) gastric resection. Our hypothesis was that the geometry of the reconstructed tract after BII resection is one of the key factors that can lead to duodenal dehiscence. We used computational fluid dynamics (CFD) with finite element (FE) simulations of various models of BII reconstructed gastrointestinal (GI) tract, as well as non-perfused, ex vivo, porcine experimental models. As main geometrical parameters for FE postoperative models we have used duodenal stump length and inclination between gastric remnant and duodenal stump. Virtual gastric resection was performed on each of 3D FE models based on multislice Computer Tomography (CT) DICOM. According to our computer simulation the difference between maximal duodenal stump pressures for models with most and least preferable geometry of reconstructed GI tract is about 30%. We compared the resulting postoperative duodenal pressure from computer simulations with duodenal stump dehiscence pressure from the experiment. Pressure at duodenal stump after BII resection obtained by computer simulation is 4-5 times lower than the dehiscence pressure according to our experiment on isolated bowel segment. Our conclusion is that if the surgery is performed technically correct, geometry variations of the reconstructed GI tract by themselves are not sufficient to cause duodenal stump blowout. Pressure that develops in the duodenal stump after BII resection using omega loop, only in the conjunction with other risk factors can cause duodenal dehiscence. Increased duodenal pressure after BII resection is risk factor. Hence we recommend the routine use of Roux en Y anastomosis as a safer solution in terms of resulting intraluminal pressure. However, if the surgeon decides to perform BII reconstruction, results obtained with this methodology can be valuable. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Forensic epidemiologic and biomechanical analysis of a pelvic cavity blowout injury associated with ejection from a personal watercraft (jet-ski).

PubMed

Freeman, Michael D; Everson, Todd M; Kohles, Sean S

2013-01-01

Jet-propelled personal watercraft (PWC) or jet-skis have become increasingly popular. The means of propulsion of PWC, which is a jet of water forced out of small nozzle at the rear of the craft, combined with a high risk of falling off of the seat and into close proximity with the water jet stream, raise the potential for a unique type of injury mechanism. The most serious injuries associated with PWC falls are those that occur when the perineum passes in close proximity to the jet nozzle and the high-pressure water stream enters the vaginal or rectal orifice. We describe the forensic investigation into a case of an anovaginal "blowout" injury in a passenger who was ejected from the rear seat position of a PWC and subsequently suffered life-threatening injuries to the pelvic organs. The investigation included a biomechanical analysis of the injury mechanism, a summary of prior published reports of internal pelvic injuries resulting from PWC falls as well as other water sports and activities, and a comparison of the severity of the injuries resulting from differing mechanisms using the New Injury Severity Score (NISS). The mean (± standard deviation [SD]) NISS values for reported PWC injuries [not including the NISS of 38 in this case study] were 11.2 (± 9.5), while the mean value for reported water-skiing falls was half that of the PWC group at 5.6 (± 5.2). It was concluded that the analyzed injuries were unique to a PWC ejection versus other previously described non-PWC-associated water sport injuries. It is recommended that PWC manufacturers help consumers understand the potential risks to passengers with highly visible warnings and reduce injury risk with revised seat design, and/or passenger seat "deadman" switches. © 2012 American Academy of Forensic Sciences.

Interstellar matter near the Pleiades. IV - The wake of the Pleiades through the interstellar medium in Taurus

NASA Technical Reports Server (NTRS)

White, Richard E.; Bally, John

1993-01-01

A large emission 'cavity' whose bright rims extend about 5 deg eastward from the Pleiades, and is pressurized by the soft-UV radiation of the cluster, has been revealed by a mosaic of IRAS images; the emission cavity delineates the wake of the Pleiades as it moves supersonically through the ISM. Photoelectric heating is identified as the most likely agent of the cluster-cloud interaction generating a shock wave, and prompts the hypothesis that transverse expansion of heated gas near the cluster plays a crucial role in driving the shock. The cloud trajectory can be traced back to an origin in Gould's Belt some 15 Myr ago, in a blowout of gas into the Galactic halo.

Electric current variations and 3D magnetic configuration of coronal jets

NASA Astrophysics Data System (ADS)

Schmieder, Brigitte; Harra, Louise K.; Aulanier, Guillaume; Guo, Yang; Demoulin, Pascal; Moreno-Insertis, Fernando, , Prof

Coronal jets (EUV) were observed by SDO/AIA on September 17, 2010. HMI and THEMIS measured the vector magnetic field from which we derived the magnetic flux, the phostospheric velocity and the vertical electric current. The magnetic configuration was computed with a non linear force-free approach. The phostospheric current pattern of the recurrent jets were associated with the quasi-separatrix layers deduced from the magnetic extrapolation. The large twisted near-by Eiffel-tower-shape jet was also caused by reconnection in current layers containing a null point. This jet cannot be classified precisely within either the quiescent or the blowout jet types. We will show the importance of the existence of bald patches in the low atmosphere

Laboratory studies of lean combustion

NASA Technical Reports Server (NTRS)

Sawyer, R. F.; Schefer, R. W.; Ganji, A. R.; Daily, J. W.; Pitz, R. W.; Oppenheim, A. K.; Angeli, J. W.

1977-01-01

The fundamental processes controlling lean combustion were observed for better understanding, with particular emphasis on the formation and measurement of gas-phase pollutants, the stability of the combustion process (blowout limits), methods of improving stability, and the application of probe and optical diagnostics for flow field characterization, temperature mapping, and composition measurements. The following areas of investigation are described in detail: (1) axisymmetric, opposed-reacting-jet-stabilized combustor studies; (2) stabilization through heat recirculation; (3) two dimensional combustor studies; and (4) spectroscopic methods. A departure from conventional combustor design to a premixed/prevaporized, lean combustion configuration is attractive for the control of oxides of nitrogen and smoke emissions, the promotion of uniform turbine inlet temperatures, and, possibly, the reduction of carbon monoxide and hydrocarbons at idle.

Detection and control of combustion instability based on the concept of dynamical system theory.

PubMed

Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

2014-02-01

We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

Deep-sea oil plume enriches psychrophilic oil-degrading bacteria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hazen, T.C.; Dubinsky, E.A.; DeSantis, T.Z.

The biological effects and expected fate of the vast amount of oil in the Gulf of Mexico from the Deepwater Horizon blowout are unknown owing to the depth and magnitude of this event. Here, we report that the dispersed hydrocarbon plume stimulated deep-sea indigenous {gamma}-Proteobacteria that are closely related to known petroleum degraders. Hydrocarbon-degrading genes coincided with the concentration of various oil contaminants. Changes in hydrocarbon composition with distance from the source and incubation experiments with environmental isolates demonstrated faster-than-expected hydrocarbon biodegradation rates at 5 C. Based on these results, the potential exists for intrinsic bioremediation of the oil plumemore » in the deep-water column without substantial oxygen drawdown.« less

Detection and control of combustion instability based on the concept of dynamical system theory

NASA Astrophysics Data System (ADS)

Gotoda, Hiroshi; Shinoda, Yuta; Kobayashi, Masaki; Okuno, Yuta; Tachibana, Shigeru

2014-02-01

We propose an online method of detecting combustion instability based on the concept of dynamical system theory, including the characterization of the dynamic behavior of combustion instability. As an important case study relevant to combustion instability encountered in fundamental and practical combustion systems, we deal with the combustion dynamics close to lean blowout (LBO) in a premixed gas-turbine model combustor. The relatively regular pressure fluctuations generated by thermoacoustic oscillations transit to low-dimensional intermittent chaos owing to the intermittent appearance of burst with decreasing equivalence ratio. The translation error, which is characterized by quantifying the degree of parallelism of trajectories in the phase space, can be used as a control variable to prevent LBO.

Star Formation in Dusty Quasars

NASA Astrophysics Data System (ADS)

Lumsden, Stuart; Croom, Scott

2012-04-01

Quasar mode feedback is thought to be a crucial ingredient in galaxy formation for luminous merging and star-bursting systems at high redshift. The energy from the active nucleus should cause significant gas outflows, reducing the available free gas reservoir for future star formation. It is currently unknown which observational state best corresponds to the stage at which this "blowout" should occur. We intend to test one possible source population for this transition phase, by studying the molecular gas content in a small, statistically complete sample of 3 K-band selected reddened quasars from the AUS survey. All lie in the redshift range 2

Altitude Performance of Annular Combustor Type Turbojet Engine with JFC-2 Fuel /james W. Useller, James L. Harp, Jr. and Zelmar Barson

NASA Technical Reports Server (NTRS)

Useller, James W; Harp, James L JR; Barson, Zelmar

1952-01-01

An investigation was made comparing the performance of JFC-2 fuel and unleaded, clear gasoline in a 3000-pound-thrust turbojet engine. The JFC-2 fuel was a blend of percent diesel fuel and 25 percent aviation gasoline. Engine combustion efficiency was equal to that obtained with gasoline at rated engine speed and altitudes up to 35,000 feet, but at lower engine speeds or at higher altitudes the JFC-2 fuel gave lower combustion efficiency. No discernible difference was obtained in starting or low-speed combustiion blow-out characteristics of the two fuels. Turbine-discharge radial temperature profiles were nearly the same at altitudes up to 35,000 feet.

Bounds on the dynamics of sink populations with noisy immigration.

PubMed

Eager, Eric Alan; Guiver, Chris; Hodgson, Dave; Rebarber, Richard; Stott, Iain; Townley, Stuart

2014-03-01

Sink populations are doomed to decline to extinction in the absence of immigration. The dynamics of sink populations are not easily modelled using the standard framework of per capita rates of immigration, because numbers of immigrants are determined by extrinsic sources (for example, source populations, or population managers). Here we appeal to a systems and control framework to place upper and lower bounds on both the transient and future dynamics of sink populations that are subject to noisy immigration. Immigration has a number of interpretations and can fit a wide variety of models found in the literature. We apply the results to case studies derived from published models for Chinook salmon (Oncorhynchus tshawytscha) and blowout penstemon (Penstemon haydenii). Copyright © 2013 Elsevier Inc. All rights reserved.

Massive blow-out craters formed by hydrate-controlled methane expulsion from the Arctic seafloor

NASA Astrophysics Data System (ADS)

Andreassen, K.; Hubbard, A.; Winsborrow, M.; Patton, H.; Vadakkepuliyambatta, S.; Plaza-Faverola, A.; Gudlaugsson, E.; Serov, P.; Deryabin, A.; Mattingsdal, R.; Mienert, J.; Bünz, S.

2017-06-01

Widespread methane release from thawing Arctic gas hydrates is a major concern, yet the processes, sources, and fluxes involved remain unconstrained. We present geophysical data documenting a cluster of kilometer-wide craters and mounds from the Barents Sea floor associated with large-scale methane expulsion. Combined with ice sheet/gas hydrate modeling, our results indicate that during glaciation, natural gas migrated from underlying hydrocarbon reservoirs and was sequestered extensively as subglacial gas hydrates. Upon ice sheet retreat, methane from this hydrate reservoir concentrated in massive mounds before being abruptly released to form craters. We propose that these processes were likely widespread across past glaciated petroleum provinces and that they also provide an analog for the potential future destabilization of subglacial gas hydrate reservoirs beneath contemporary ice sheets.

Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Mitra, Siddhartha; Kimmel, David G.; Snyder, Jessica; Scalise, Kimberly; McGlaughon, Benjamin D.; Roman, Michael R.; Jahn, Ginger L.; Pierson, James J.; Brandt, Stephen B.; Montoya, Joseph P.; Rosenbauer, Robert J.; Lorenson, Thomas D.; Wong, Florence L.; Campbell, Pamela L.

2012-01-01

Mesozooplankton (>200 μm) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/V Deepwater Horizon blowout. Mesozooplankton contained 0.03-97.9 ng g-1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem.

Effects of percentage of blockage and flameholder downstream counterbores on lean combustion limits of premixed, prevaporized propane-air mixture

NASA Technical Reports Server (NTRS)

Fernandez, M. A. B.

1983-01-01

Lean combustion limits were determined for a premixed prevaporized propane air mixture with flat plate flame stabilizers. Experiments were conducted in a constant area flame tube combustor utilizing flameholders of varying percentages of blockage and downstream counterbores. Combustor inlet air velocity at ambient conditions was varied from 4 to 9 meters per second. Flameholders with a center hole and four half holes surrounding it were tested with 63, 73, and 85 percent blockage and counterbore diameters of 112 and 125 percent of the thru hole diameter, in addition to the no counterbore configuration. Improved stability was obtained by using counterbore flameholders and higher percentages of blockage. Increases in mixture velocity caused the equivalence ratio at blowout to increase in all cases.

Augmentor performance of an F100 engine model derivative engine in an F-15 airplane

NASA Technical Reports Server (NTRS)

Walton, James T.; Burcham, Frank W., Jr.

1986-01-01

The transient performance of the F100 engine model derivative (EMD) augmentor was evaluated in an F-15 airplane. The augmentor was a newly designed 16-segment augmentor. It was tested with a segment-1 sprayring with 90 deg fuel injection, and later with a modified segment-1 sprayring with centerline fuel injection. With the 90 deg injection, no-lights occurred at high altitudes with airspeeds of 175 knots or less; however, the results were better than when using the standard F100-PW-100 engine. With the centerline fuel injection, all transients were successful to an altitude of 15,500 meters and an airspeed of 150 knots: no failures to light, blowouts, or stalls occurred. For a first flight evaluation, the augmentor transient performance was excellent.

Laser dynamics in transversely inhomogeneous plasma and its relevance to wakefield acceleration

NASA Astrophysics Data System (ADS)

Pathak, V. B.; Vieira, J.; Silva, L. O.; Nam, Chang Hee

2018-05-01

We present full set of coupled equations describing the weakly relativistic dynamics of a laser in a plasma with transverse inhomogeneity. We apply variational principle approach to obtain these coupled equations governing laser spot-size, transverse wavenumber, curvature, transverse centroid, etc. We observe that such plasma inhomogeneity can lead to stronger self-focusing. We further discuss the guiding conditions of laser in parabolic plasma channels. With the help of multi-dimensional particle in cell simulations the study is extended to the blowout regime of laser wakefield acceleration to show laser as well as self-injected electron bunch steering in plasma to generate unconventional particle trajectories. Our simulation results demonstrate that such transverse inhomogeneities due to asymmetric self focusing lead to asymmetric bubble excitation, thus inducing off-axis self-injection.

Macondo-1 well oil-derived polycyclic aromatic hydrocarbons in mesozooplankton from the northern Gulf of Mexico

USGS Publications Warehouse

Mitra, Siddhartha; Kimmel, David G.; Snyder, Jessica; Scalise, Kimberly; McGlaughon, Benjamin D.; Roman, Michael R.; Jahn, Ginger L.; Pierson, James J.; Brandt, Stephen B.; Montoya, Joseph P.; Rosenbauer, Robert J.; Lorenson, T.D.; Wong, Florence L.; Campbell, Pamela L.

2012-01-01

Mesozooplankton (>200 μm) collected in August and September of 2010 from the northern Gulf of Mexico show evidence of exposure to polycyclic aromatic hydrocarbons (PAHs). Multivariate statistical analysis revealed that distributions of PAHs extracted from mesozooplankton were related to the oil released from the ruptured British Petroleum Macondo-1 (M-1) well associated with the R/VDeepwater Horizon blowout. Mesozooplankton contained 0.03–97.9 ng g−1 of total PAHs and ratios of fluoranthene to fluoranthene + pyrene less than 0.44, indicating a liquid fossil fuel source. The distribution of PAHs isolated from mesozooplankton extracted in this study shows that the 2010 Deepwater Horizon spill may have contributed to contamination in the northern Gulf of Mexico ecosystem.

Methane gas seepage - Disregard of significant water column filter processes?

NASA Astrophysics Data System (ADS)

Schneider von Deimling, Jens; Schmale, Oliver

2016-04-01

Marine methane seepage represents a potential contributor for greenhouse gas in the atmosphere and is discussed as a driver for climate change. The ultimate question is how much methane is released from the seafloor on a global scale and what fraction may reach the atmosphere? Dissolved fluxes from methane seepage sites on the seabed were found to be very efficiently reduced by benthic microbial oxidation, whereas transport of free gas bubbles from the seabed is considered to bypass the effective benthic methane filter. Numerical models are available today to predict the fate of such methane gas bubble release to the water column in regard to gas exchange with the ambient water column, respective bubble lifetime and rise height. However, the fate of rising gas bubbles and dissolved methane in the water column is not only governed by dissolution, but is also affected by lateral oceanographic currents and vertical bubble-induced upwelling, microbial oxidation, and physico-chemical processes that remain poorly understood so far. According to this gap of knowledge we present data from two study sites - the anthropogenic North Sea 22/4b Blowout and the natural Coal Oil point seeps - to shed light into two new processes gathered with hydro-acoustic multibeam water column imaging and microbial investigations. The newly discovered processes are hereafter termed Spiral Vortex and Bubble Transport Mechanism. Spiral Vortex describes the evolution of a complex vortical fluid motion of a bubble plume in the wake of an intense gas release site (Blowout, North Sea). It appears very likely that it dramatically changes the dissolution kinetics of the seep gas bubbles. Bubble Transport Mechanism prescribes the transport of sediment-hosted bacteria into the water column via rising gas bubbles. Both processes act as filter mechanisms in regard to vertical transport of seep related methane, but have not been considered before. Spiral Vortex and Bubble Transport Mechanism represent the basis for a follow up research scheduled for August 2016 with the R/V POSEIDON with the aim to better constrain their mechanisms and to quantify their overall importance.

Scientific Studies in Support of Shutting In the Macondo Well (Deepwater Horizon) Blowout, Gulf of Mexico (Invited)

NASA Astrophysics Data System (ADS)

Hickman, S.; Mooney, W. D.; Hsieh, P. A.; Enomoto, C.; Nelson, P. H.; McNutt, M.

2010-12-01

Scientists, engineers and managers from BP, other private companies, universities, government research labs and a broad spectrum of federal agencies have formed a unique cooperative working relationship in responding to the Macondo oil well (Deepwater Horizon) blowout. Among the many activities performed during this effort, U.S. Geological Survey personnel evaluated the potential geologic hazard of shutting in the Macondo well at the sea floor, and collectively decided, with others, the conditions under which it could be safely undertaken. These hazards included the possible loss of wellbore integrity under the anticipated high shut-in pressures, potentially leading to new pathways for hydrocarbon release to the Gulf of Mexico through upward hydraulic fracture propagation and/or soft sediment erosion initiating at possible leak points in the cemented casing. This hazard evaluation required analysis of 2D and 3D seismic surveys, seafloor bathymetry, pressure transient tests, geophysical well logs, in-situ stress (“leak-off”) tests and drilling data (e.g., mud logs) to assess the geological, hydrological and geomechanical conditions at and around the Macondo well. After the well was successfully capped and shut in by BP on July 15, a variety of monitoring practices were put into place to guard against further leaks into the Gulf. These monitoring activities included acquisition of wellhead pressure data, marine multi-channel seismic profiles, sea-floor and sea-surface sonar surveys (the latter using the NOAA RV/Pisces), and wellhead visual/acoustic monitoring. Scientists and engineers from BP, outside consultants, government agencies and the university community then worked together to continuously evaluate these data to ensure that the well remained safely shut in until reservoir pressures were suppressed (“killed”) with heavy drilling mud and the well was sealed with cement. This effort to shut in and then permanently seal the blown-out Macondo well has involved an unprecedented level of interaction, collaboration and coordination among scientists, engineers, managers and emergency response officials, and will hopefully lead to improved methodologies and approaches to assessing and then mitigating hazards posed by deepwater drilling.

Sustained in situ measurements of dissolved oxygen, methane and water transport processes in the benthic boundary layer at MC118, northern Gulf of Mexico

NASA Astrophysics Data System (ADS)

Martens, Christopher S.; Mendlovitz, Howard P.; Seim, Harvey; Lapham, Laura; D'Emidio, Marco

2016-07-01

Within months of the BP Macondo Wellhead blowout, elevated methane concentrations within the water column revealed a significant retention of light hydrocarbons in deep waters plus corresponding dissolved oxygen (DO) deficits. However, chemical plume tracking efforts were hindered by a lack of in situ monitoring capabilities. Here, we describe results from in situ time-series, lander-based investigations of physical and biogeochemical processes controlling dissolved oxygen, and methane at Mississippi Canyon lease block 118 ( 18 km from the oil spill) conducted shortly after the blowout through April 2012. Multiple sensor arrays plus open-cylinder flux chambers (;chimneys;) deployed from a benthic lander collected oxygen, methane, pressure, and current speed and direction data within one meter of the seafloor. The ROVARD lander system was deployed for an initial 21-day test experiment (9/13/2010-10/04/2010) at 882 m depth before a longer 160-day deployment (10/24/2011-4/01/2012) at 884 m depth. Temporal variability in current directions and velocities and water temperatures revealed strong influences of bathymetrically steered currents and overlying along-shelf flows on local and regional water transport processes. DO concentrations and temperature were inversely correlated as a result of water mass mixing processes. Flux chamber measurements during the 160-day deployment revealed total oxygen utilization (TOU) averaging 11.6 mmol/m2 day. Chimney DO concentrations measured during the 21-day deployment exhibited quasi-daily variations apparently resulting from an interaction between near inertial waves and the steep topography of an elevated scarp immediately adjacent to the 21-day deployment site that modulated currents at the top of the chimney. Variability in dissolved methane concentrations suggested significant temporal variability in gas release from nearby hydrocarbon seeps and/or delivery by local water transport processes. Free-vehicle (lander) monitoring over time scales of months to years utilizing in situ sensors can provide an understanding of processes controlling water transport, respiration and the fate and impacts of accidental and natural gas and oil releases.

The effect of fuel/air mixer design parameters on the continuous and discrete phase structure in the reaction-stabilizing region

NASA Astrophysics Data System (ADS)

Ateshkadi, Arash

The demands on current and future aero gas turbine combustors are demanding a greater insight into the role of the injector/dome design on combustion performance. The structure of the two-phase flow and combustion performance associated with practical injector/dome hardware is thoroughly investigated. A spray injector with two radial inflow swirlers was custom-designed to maintain tight tolerances and strict assembly protocol to isolate the sensitivity of performance to hardware design. The custom set is a unique modular design that (1) accommodates parametric variation in geometry, (2) retains symmetry, and (3) maintains effective area. Swirl sense and presence of a venturi were found to be the most influential on fuel distribution and Lean Blowout. The venturi acts as a fuel-prefilming surface and constrains the highest fuel mass concentration to an annular ring near the centerline. Co-swirl enhances the radial dispersion of the continuous phase and counter-swirl increases the level of mixing that occurs in the downstream region of the mixer. The smallest drop size distributions were found to occur with the counter-swirl configuration with venturi. In the case of counter-swirl without venturi the high concentration of fluid mass is found in the center region of the flow. The Lean Blowout (LBO) equivalence ratio was lower for counter-swirl due to the coupling of the centerline recirculation zone with the location of high fuel concentration emanating from smaller droplets. In the co-swirl configuration a more intense reaction was found near the mixer exit leading to the lowest concentration of NOx, CO and UHC. An LBO model with good agreement to the measured values was developed that related, for the first time, specific hardware parameters and operating condition to stability performance. A semi-analytical model, which agreed best with co-swirl configurations, was modified and used to describe the axial velocity profile downstream of the mixer exit. The development of these two models exemplifies the use of mathematical expressions to guide the design and development procedure for mixer geometry that meet the stringent demands on increasing combustion performance.

Taming a wild geothermal research well in yellowstone national park

USGS Publications Warehouse

Fournier, Robert O.; Pisto, Larry M.; Howell, Bruce B.; Hutchnson, Roderick A.; ,

1993-01-01

In November 1992 the valve at the top of a U.S. Geological Survey drill hole in Yellowstone National Park parted from the casting as a result of corrosion. This allowed uncontrolled venting of boiling water and steam from the well at an estimated liquid flow rate of about 25-50 gallons per minute. A flow diverter assembly was designed, fabricated and installed on the well within 16 days, which allowed drill rods to be safely stripped into the well through on annular Blow-Out Preventer. Once this was accomplished it was a relatively routine matter to set a packer in the casting and cement the well shut permanently. The drill hole was brought under control and cemented shut within 18 days of the wellhead failure at a total cost of $47,066, which was about $5,000 less than anticipated.

Time varying voltage combustion control and diagnostics sensor

DOEpatents

Chorpening, Benjamin T [Morgantown, WV; Thornton, Jimmy D [Morgantown, WV; Huckaby, E David [Morgantown, WV; Fincham, William [Fairmont, WV

2011-04-19

A time-varying voltage is applied to an electrode, or a pair of electrodes, of a sensor installed in a fuel nozzle disposed adjacent the combustion zone of a continuous combustion system, such as of the gas turbine engine type. The time-varying voltage induces a time-varying current in the flame which is measured and used to determine flame capacitance using AC electrical circuit analysis. Flame capacitance is used to accurately determine the position of the flame from the sensor and the fuel/air ratio. The fuel and/or air flow rate (s) is/are then adjusted to provide reduced flame instability problems such as flashback, combustion dynamics and lean blowout, as well as reduced emissions. The time-varying voltage may be an alternating voltage and the time-varying current may be an alternating current.

Afterburner Performance of Circular V-Gutters and a Sector of Parallel V-Gutters for a Range of Inlet Temperatures to 1255 K (1800 F)

NASA Technical Reports Server (NTRS)

Brandstetter, J. Robert; Reck, Gregory M.

1973-01-01

Combustion tests of two V-gutter types were conducted in a 19.25-in. diameter duct using vitiated air. Fuel spraybars were mounted in line with the V-gutters. Combustor length was set by flame-quench water sprays which were part of a calorimeter for measuring combustion efficiency. Although the levels of performance of the parallel and circular array afterburners were different, the trends with geometry variations were consistent. Therefore, parallel arrays can be used for evaluating V-gutter geometry effects on combustion performance. For both arrays, the highest inlet temperature produced combustion efficiencies near 100 percent. A 5-in. spraybar - to - V-gutter spacing gave higher efficiency and better lean blowout performance than a spacing twice as large. Gutter durability was good.

Nucleation of stable superconductivity in YBCO-films

NASA Astrophysics Data System (ADS)

Kötzler, J.

By means of the linear dynamic conductivity, inductively measured on epitaxial films between 30mHz and 30 MHz, the transition line T g (B) to generic superconductivity is studied in fields between B=0 and 19T. It follows closely the melting line T m (B) described recently in terms of a blowout of thermal vortex loops in clean materials. The critical exponents of the correlation length and time near T g (B), however, enem to be dominated by some intrinsic disorder. Columnar defects produced by heavy-ion irradiation up to field-equivalent-doses of B ϕ =10T lead to adisappointing reduction of T g (B→0) while for B>B ϕ the generic line of the pristine film is recovered. These novel results are also discussed in terms of a loop-driven destruction of generic superconductivity.

Modelling oil plumes from subsurface spills.

PubMed

Lardner, Robin; Zodiatis, George

2017-11-15

An oil plume model to simulate the behavior of oil from spills located at any given depth below the sea surface is presented, following major modifications to a plume model developed earlier by Malačič (2001) and drawing on ideas in a paper by Yapa and Zheng (1997). The paper presents improvements in those models and numerical testing of the various parameters in the plume model. The plume model described in this paper is one of the numerous modules of the well-established MEDSLIK oil spill model. The deep blowout scenario of the MEDEXPOL 2013 oil spill modelling exercise, organized by REMPEC, has been applied using the improved oil plume module of the MEDSLIK model and inter-comparison with results having the oil spill source at the sea surface are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Encroachment of oriental bittersweet into Pitcher’s thistle habitat

USGS Publications Warehouse

Leicht-Young, Stacey A.; Pavlovic, Noel B.

2012-01-01

Common invasive species and rare endemic species can grow and interact at the ecotone between forested and non-forested dune habitats. To investigate these interactions, a comparison of the proximity and community associates of a sympatric invasive (Celastrus orbiculatus; oriental bittersweet) and native (C. scandens; American bittersweet) liana species to federally threatened Cirsium pitcheri (Pitcher's thistle) in the dunes habitats of Lake Michigan was conducted. Overall, the density of the invasive liana species was significantly greater in proximity to C. pitcheri than the native species. On the basis of composition, the three focal species occurred in both foredune and blowout habitats. The plant communities associated with the three focal species overlapped in ordination space, but there were significant differences in composition. The ability of C. orbiculatus to rapidly grow and change the ecological dynamics of invasion sites adds an additional threat to the successional habitats of C. pitcheri.

The XMM-Newton View of Wolf-Rayet Bubbles

NASA Astrophysics Data System (ADS)

Guerrero, M.; Toala, J.

2017-10-01

The powerful stellar winds of Wolf-Rayet (WR) stars blow large bubble into the circumstellar material ejected in previous phases of stellar evolution. The shock of those stellar winds produces X-ray-emitting hot plasmas which tells us about the diffusion of processed material onto the interstellar medium, about processes of heat conduction and turbulent mixing at the interface, about the late stages of stellar evolution, and about the shaping of the circumstellar environment, just before supernova explosions. The unique sensitivity of XMM-Newton has been key for the detection, mapping and spectral analysis of the X-ray emission from the hot bubbles around WR stars. These observations underscore the importance of the structure of the interstellar medium around massive stars, but they have also unveiled unknown phenomena, such as blowouts of hot gas into the interstellar medium or spatially-resolved spectral properties of the hot gas, which disclose inhomogeneous chemical abundances and physical properties across these bubbles.

A Novel Cardiotoxic Mechanism for a Pervasive Global Pollutant

NASA Astrophysics Data System (ADS)

Brette, Fabien; Shiels, Holly A.; Galli, Gina L. J.; Cros, Caroline; Incardona, John P.; Scholz, Nathaniel L.; Block, Barbara A.

2017-01-01

The Deepwater Horizon disaster drew global attention to the toxicity of crude oil and the potential for adverse health effects amongst marine life and spill responders in the northern Gulf of Mexico. The blowout released complex mixtures of polycyclic aromatic hydrocarbons (PAHs) into critical pelagic spawning habitats for tunas, billfishes, and other ecologically important top predators. Crude oil disrupts cardiac function and has been associated with heart malformations in developing fish. However, the precise identity of cardiotoxic PAHs, and the mechanisms underlying contractile dysfunction are not known. Here we show that phenanthrene, a PAH with a benzene 3-ring structure, is the key moiety disrupting the physiology of heart muscle cells. Phenanthrene is a ubiquitous pollutant in water and air, and the cellular targets for this compound are highly conserved across vertebrates. Our findings therefore suggest that phenanthrene may be a major worldwide cause of vertebrate cardiac dysfunction.

Static and dynamic deflection studies of the SRM aft case-nozzle joint

NASA Technical Reports Server (NTRS)

Christian, David C.; Kos, Lawrence D.; Torres, Isaias

1989-01-01

The redesign of the joints on the solid rocket motor (SRM) has prompted the need for analyzing the behavior of the joints using several different types of analyses. The types of analyses performed include modal analysis, static analysis, transient response analysis, and base driving response analysis. The forces used in these analyses to drive the mathematical model include SRM internal chamber pressure, nozzle blowout and side forces, shuttle vehicle lift-off dynamics, SRM pressure transient rise curve, gimbal forces and moments, actuator gimbal loads, and vertical and radial bolt preloads. The math model represented the SRM from the aft base tangent point (1,823.95 in) all the way back to the nozzle, where a simplified, tuned nozzle model was attached. The new design used the radial bolts as an additional feature to reduce the gap opening at the aft dome/nozzle fixed housing interface.

Sensitivity of Combustion-Acoustic Instabilities to Boundary Conditions for Premixed Gas Turbine Combustors

NASA Technical Reports Server (NTRS)

Darling, Douglas; Radhakrishnan, Krishnan; Oyediran, Ayo

1995-01-01

Premixed combustors, which are being considered for low NOx engines, are susceptible to instabilities due to feedback between pressure perturbations and combustion. This feedback can cause damaging mechanical vibrations of the system as well as degrade the emissions characteristics and combustion efficiency. In a lean combustor instabilities can also lead to blowout. A model was developed to perform linear combustion-acoustic stability analysis using detailed chemical kinetic mechanisms. The Lewis Kinetics and Sensitivity Analysis Code, LSENS, was used to calculate the sensitivities of the heat release rate to perturbations in density and temperature. In the present work, an assumption was made that the mean flow velocity was small relative to the speed of sound. Results of this model showed the regions of growth of perturbations to be most sensitive to the reflectivity of the boundary when reflectivities were close to unity.

Research and application of borehole structure optimization based on pre-drill risk assessment

NASA Astrophysics Data System (ADS)

Zhang, Guohui; Liu, Xinyun; Chenrong; Hugui; Yu, Wenhua; Sheng, Yanan; Guan, Zhichuan

2017-11-01

Borehole structure design based on pre-drill risk assessment and considering risks related to drilling operation is the pre-condition for safe and smooth drilling operation. Major risks of drilling operation include lost circulation, blowout, sidewall collapsing, sticking and failure of drilling tools etc. In the study, studying data from neighboring wells was used to calculate the profile of formation pressure with credibility in the target well, then the borehole structure design for the target well assessment by using the drilling risk assessment to predict engineering risks before drilling. Finally, the prediction results were used to optimize borehole structure design to prevent such drilling risks. The newly-developed technique provides a scientific basis for lowering probability and frequency of drilling engineering risks, and shortening time required to drill a well, which is of great significance for safe and high-efficient drilling.

Non-technical skills: enhancing safety in operating theatres (and drilling rigs).

PubMed

Flin, Rhona

2014-03-01

On April 20th 2010, a large Transocean drilling rig called the Deepwater Horizon was operating in the Gulf of Mexico to drill the Macondo well, for the oil company BP. The job was six weeks behind schedule and $58 million over budget and had not been without difficulty: it was a high pressure well, 2.5 miles below the seabed. At 5.45 am, the Halliburton cementing engineer sent an email to say: 'We have completed the job and it went well'. At 9.43 pm, 16 hours later, there was a release of hydrocarbons into the well bore and the drilling rig experienced a catastrophic blowout as the high pressure oil and gas escaped onto the rig and into the ocean. The resulting explosions and fire killed 11 of the crew of 126, injured many more and created an enormous oil spill across the Gulf.

Applications of science and engineering to quantify and control the Deepwater Horizon oil spill

PubMed Central

McNutt, Marcia K.; Chu, Steven; Lubchenco, Jane; Hunter, Tom; Dreyfus, Gabrielle; Murawski, Steven A.; Kennedy, David M.

2012-01-01

The unprecedented engagement of scientists from government, academia, and industry enabled multiple unanticipated and unique problems to be addressed during the Deepwater Horizon oil spill. During the months between the initial blowout on April 20, 2010, and the final well kill on September 19, 2010, researchers prepared options, analyses of tradeoffs, assessments, and calculations of uncertainties associated with the flow rate of the well, well shut in, killing the well, and determination of the location of oil released into the environment. This information was used in near real time by the National Incident Commander and other government decision-makers. It increased transparency into BP’s proposed actions and gave the government confidence that, at each stage proposed, courses of action had been thoroughly vetted to reduce risk to human life and the environment and improve chances of success. PMID:23213225

Combustor exhaust emissions with air-atomizing splash-groove fuel injectors burning Jet A and Diesel number 2 fuels

NASA Technical Reports Server (NTRS)

Ingebo, R. D.; Norgren, C. T.

1975-01-01

Air-atomizing, splash-groove injectors were shown to improve primary-zone fuel spreading and reduce combustor exhaust emissions for Jet A and diesel number 2 fuels. With Jet A fuel large-orifice, splash-groove injectors the oxides-of-nitrogen emission index was reduced, but emissions of carbon monoxide, unburned hydrocarbons, or smoke were unaffected. Small-orifice, splash-groove injectors did not reduce oxides of nitrogen, but reduced the smoke number and carbon monoxide and unburned-hydrocarbon emission indices. With diesel number 2 fuel, the small-orifice, splash-groove injectors reduced oxides of nitrogen by 19 percent, smoke number by 28 percent, carbon monoxide by 75 percent, and unburned hydrocarbons by 50 percent. Smoke number and unburned hydrocarbons were twice as high with diesel number 2 as with Jet A fuel. Combustor blowout limits were similar for diesel number 2 and Jet A fuels.

Idealized gas turbine combustor for performance research and validation of large eddy simulations.

PubMed

Williams, Timothy C; Schefer, Robert W; Oefelein, Joseph C; Shaddix, Christopher R

2007-03-01

This paper details the design of a premixed, swirl-stabilized combustor that was designed and built for the express purpose of obtaining validation-quality data for the development of large eddy simulations (LES) of gas turbine combustors. The combustor features nonambiguous boundary conditions, a geometrically simple design that retains the essential fluid dynamics and thermochemical processes that occur in actual gas turbine combustors, and unrestrictive access for laser and optical diagnostic measurements. After discussing the design detail, a preliminary investigation of the performance and operating envelope of the combustor is presented. With the combustor operating on premixed methane/air, both the equivalence ratio and the inlet velocity were systematically varied and the flame structure was recorded via digital photography. Interesting lean flame blowout and resonance characteristics were observed. In addition, the combustor exhibited a large region of stable, acoustically clean combustion that is suitable for preliminary validation of LES models.

Cooperation, logistics critical to well control operation in Irian Jaya jungle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gebhardt, F.; Leturno, R.

1996-04-15

Solving a well control problem in remote Irian Jaya, Indonesia, required fast regional and international transportation of both people and equipment. Initial information indicated that the well was experiencing an underground flow with a constant surface pressure because of a shallow hole in the 9 5/8-in. casing. The surface pressure made pipe movement inadvisable until proper pressure control equipment was in place. Several factors contributed to the overall success of this well control project. Atlantic Richfield Indonesia Inc.`s commitment to blowout contingency planning and well control team made it possible to institute a predetermined organizational structure. This organization structure providedmore » a means to gather and evaluate data quickly. Thus, crucial decisions could be made without delay, and proper personnel and equipment were mobilized. This paper reviews the step-by-step process used in this effort.« less

Glacigenic sedimentation pulses triggered post-glacial gas hydrate dissociation.

PubMed

Karstens, Jens; Haflidason, Haflidi; Becker, Lukas W M; Berndt, Christian; Rüpke, Lars; Planke, Sverre; Liebetrau, Volker; Schmidt, Mark; Mienert, Jürgen

2018-02-12

Large amounts of methane are stored in continental margins as gas hydrates. They are stable under high pressure and low, but react sensitively to environmental changes. Bottom water temperature and sea level changes were considered as main contributors to gas hydrate dynamics after the last glaciation. However, here we show with numerical simulations that pulses of increased sedimentation dominantly controlled hydrate stability during the end of the last glaciation offshore mid-Norway. Sedimentation pulses triggered widespread gas hydrate dissociation and explains the formation of ubiquitous blowout pipes in water depths of 600 to 800 m. Maximum gas hydrate dissociation correlates spatially and temporally with the formation or reactivation of pockmarks, which is constrained by radiocarbon dating of Isorropodon nyeggaensis bivalve shells. Our results highlight that rapid changes of sedimentation can have a strong impact on gas hydrate systems affecting fluid flow and gas seepage activity, slope stability and the carbon cycle.

Initiation of Martian Outflow Channels: Related to the Dissociation of Gas Hydrate?

NASA Technical Reports Server (NTRS)

Max, Michael D.; Clifford, Stephen M.

2001-01-01

We propose that the disruption of subpermafrost aquifers on Mars by the thermal- or pressure-induced dissociation of methane hydrate may have been a frequent trigger for initiating outflow channel activity. This possibility is raised by recent work that suggests that significant amounts of methane and gas hydrate may have been produced within and beneath the planet's cryosphere. On Earth, the build-up of overpressured water and gas by the decomposition of hydrate deposits has been implicated in the formation of large blowout features on the ocean floor. These features display a remarkable resemblance (in both morphology and scale) to the chaotic terrain found at the source of many Martian channels. The destabilization of hydrate can generate pressures sufficient to disrupt aquifers confined by up to 5 kilometers of frozen ground, while smaller discharges may result from the water produced by the decomposition of near-surface hydrate alone.

Plasma density limits for hole boring by intense laser pulses.

PubMed

Iwata, Natsumi; Kojima, Sadaoki; Sentoku, Yasuhiko; Hata, Masayasu; Mima, Kunioki

2018-02-12

High-power lasers in the relativistic intensity regime with multi-picosecond pulse durations are available in many laboratories around the world. Laser pulses at these intensities reach giga-bar level radiation pressures, which can push the plasma critical surface where laser light is reflected. This process is referred to as the laser hole boring (HB), which is critical for plasma heating, hence essential for laser-based applications. Here we derive the limit density for HB, which is the maximum plasma density the laser can reach, as a function of laser intensity. The time scale for when the laser pulse reaches the limit density is also derived. These theories are confirmed by a series of particle-in-cell simulations. After reaching the limit density, the plasma starts to blowout back toward the laser, and is accompanied by copious superthermal electrons; therefore, the electron energy can be determined by varying the laser pulse length.

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

Trinity Gas Corp. officials signed an agreement on May 20, 1997, with the Cauca Valley Corp. (CVC) allowing Trinity to use CVC data to explore for natural gas in the Cauca Valley of Colombia. CVC, Colombia`s Valle del Cauca water resources and environmental division, is evaluating Colombia`s underground water reserves to protect, control and preserve fresh water aquifers, some of which contain natural gas pockets that cause blowouts in farmers` water wells. Preparations now are underway for drilling Trinity`s first well at the Palmira 1 site on the San Jose Hacienda, the largest privately owned sugar cane plantation in themore » valley. Trinity also entered into an agreement with the Cauca Valley Natural Gas and Electricity Project to furnish natural gas, generated electricity and energy fuel for the industrial district in the region. According to this contract, many valley residents will have electric service for the first time.« less

Experimental signatures of direct-laser-acceleration-assisted laser wakefield acceleration

NASA Astrophysics Data System (ADS)

Shaw, J. L.; Lemos, N.; Marsh, K. A.; Froula, D. H.; Joshi, C.

2018-04-01

The direct laser acceleration (DLA) of electrons in a laser wakefield accelerator (LWFA) operating in the forced or quasi-blowout regimes has been investigated through experiment and simulation. When there is a significant overlap between the trapped electrons and the drive laser in a LWFA cavity, the resulting electrons can gain energy from both the LWFA and the DLA mechanisms. Experimental work investigates the properties of the electron beams produced in a LWFA with ionization injection by dispersing those beams in the direction perpendicular to the laser polarization. These electron beams show certain spectral features that are characteristic of DLA. These characteristic features are reproduced using particle-in-cell simulations, where particle tracking was used to elucidate the roles of LWFA and DLA to the energy gain of the electrons in this experimental regime and to demonstrate that such spectral features are definitive signatures of the presence of DLA in LWFA.

Game story space of professional sports: Australian rules football

NASA Astrophysics Data System (ADS)

Kiley, Dilan Patrick; Reagan, Andrew J.; Mitchell, Lewis; Danforth, Christopher M.; Dodds, Peter Sheridan

2016-05-01

Sports are spontaneous generators of stories. Through skill and chance, the script of each game is dynamically written in real time by players acting out possible trajectories allowed by a sport's rules. By properly characterizing a given sport's ecology of "game stories," we are able to capture the sport's capacity for unfolding interesting narratives, in part by contrasting them with random walks. Here we explore the game story space afforded by a data set of 1310 Australian Football League (AFL) score lines. We find that AFL games exhibit a continuous spectrum of stories rather than distinct clusters. We show how coarse graining reveals identifiable motifs ranging from last-minute comeback wins to one-sided blowouts. Through an extensive comparison with biased random walks, we show that real AFL games deliver a broader array of motifs than null models, and we provide consequent insights into the narrative appeal of real games.

Applications of science and engineering to quantify and control the Deepwater Horizon oil spill

USGS Publications Warehouse

McNutt, Marcia K.; Chu, Steven; Lubchenco, Jane; Hunter, Tom; Dreyfus, Gabrielle; Murawski, Steven A.; Kennedy, David M.

2012-01-01

The unprecedented engagement of scientists from government, academia, and industry enabled multiple unanticipated and unique problems to be addressed during the Deepwater Horizon oil spill. During the months between the initial blowout on April 20, 2010, and the final well kill on September 19, 2010, researchers prepared options, analyses of tradeoffs, assessments, and calculations of uncertainties associated with the flow rate of the well, well shut in, killing the well, and determination of the location of oil released into the environment. This information was used in near real time by the National Incident Commander and other government decision-makers. It increased transparency into BP’s proposed actions and gave the government confidence that, at each stage proposed, courses of action had been thoroughly vetted to reduce risk to human life and the environment and improve chances of success.

Laparoscopic management for spontaneous jejunal perforation caused by nonspecific ulcer: A case report.

PubMed

Sakaguchi, Tatsuma; Tokuhara, Katsuji; Nakatani, Kazuyoshi; Kon, Masanori

2017-01-01

Nonspecific small bowel ulcers are rare and there have been limited reports. We applied laparoscopic surgery successfully for the perforation caused by this disease of jejunum. A 70-year-old man visited to our hospital with complaint of abdominal pain and fever. He was diagnosed abdominal peritonitis with findings of intraperitoneal gas and fluid. Emergency laparoscopic surgery was performed. A perforation 5mm in diameter was recognized in jejunum opposite side of mesentery. Partial resection of jejunum with end-to-end anastomosis and peritoneal lavage were performed. Pathologically, an ulcer was recognized around the blowout perforation without specific inflammation. He was discharged uneventfully 12days after surgery. Laparoscopic surgery has diagnostic and therapeutic advantages because of its lower invasion with a good operation view, and in case of the small bowel, it is easy to shift extra-corporeal maneuver. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Subsurface safety valves: safety asset or safety liability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Busch, J.M.; Llewelyn, D.C.G.; Policky, B.J.

1983-10-01

This paper summarizes the methods used to compare the risk of a blowout for a well completed with a subsurface safety valve (SSSV) vs. a completion without an SSSV. These methods, which could be applied to any field, include a combination of SSSV reliability and conventional risk analyses. The Kuparuk River Unit Working Interest Owners recently formed a group to examine the risks associated with installing and maintaining SSSV's in the Kuparuk field. The group was charged with answering the question: ''Assuming Kuparuk field operating conditions, are SSSV's a safety asset, or do numerous operating and maintenance procedures make themmore » a safety liability.'' The results indicate that for the Kuparuk River Unit, an SSSV becomes a safety liability when the mean time between SSSV failures is less than one year. Since current SSSV mean time to failure (MTTF) at Kuparuk is approximately 1000 days, they are considered a safety asset.« less

Impact of climate change and seasonal trends on the fate of Arctic oil spills.

PubMed

Nordam, Tor; Dunnebier, Dorien A E; Beegle-Krause, C J; Reed, Mark; Slagstad, Dag

2017-12-01

We investigated the effects of a warmer climate, and seasonal trends, on the fate of oil spilled in the Arctic. Three well blowout scenarios, two shipping accidents and a pipeline rupture were considered. We used ensembles of numerical simulations, using the OSCAR oil spill model, with environmental data for the periods 2009-2012 and 2050-2053 (representing a warmer future) as inputs to the model. Future atmospheric forcing was based on the IPCC's A1B scenario, with the ocean data generated by the hydrodynamic model SINMOD. We found differences in "typical" outcome of a spill in a warmer future compared to the present, mainly due to a longer season of open water. We have demonstrated that ice cover is extremely important for predicting the fate of an Arctic oil spill, and find that oil spills in a warming climate will in some cases result in greater areal coverage and shoreline exposure.

Mechanisms of Plasma Acceleration in Coronal Jets

NASA Astrophysics Data System (ADS)

Soto, N.; Reeves, K.; Savcheva, A. S.

2016-12-01

Jets are small explosions that occur frequently in the Sun possibly driven by the local reconfiguration of the magnetic field, or reconnection. There are two types of coronal jets: standard jets and blowout jets. The purpose of this project is to determine which mechanisms accelerate plasma in two different jets, one that occurred in January 17, 2015 at the disk of the sun and another in October 24, 2015 at the limb. Two possible acceleration mechanisms are chromospheric evaporation and magnetic acceleration. Using SDO/AIA, Hinode/XRT and IRIS data, we create height-time plots, and calculate the velocities of each wavelength for both jets. We calculate the potential magnetic field of the jet and the general region around it to gain a more detailed understanding of its structure, and determine if the jet is likely to be either a standard or blowout jet. Finally, we calculate the magnetic field strength for different heights along the jet spire, and use differential emission measures to calculate the plasma density. Once we have these two values, we calculate the Alfven speed. When analyzing our results we are looking for certain patterns in our velocities. If the plasma in a jet is accelerated by chromospheric evaporation, we expect the velocities to increase as function of temperature, which is what we observed in the October 24th jet. The magnetic models for this jet also show the Eiffel Tower shaped structure characteristic of standard jets, which tend to have plasma accelerated by this mechanism. On the other hand, if the acceleration mechanism were magnetic acceleration, we would expect the velocities to be similar regardless of temperature. For the January 17th jet, we saw that along the spire, the velocities where approximately 200 km/s in all wavelengths, but the velocities of hot plasma detected at the base were closer to the Alfven speed, which was estimated to be about 2,000 km/s. These observations suggest that the plasma in the January 17th jet is magnetically accelerated. The magnetic model for this jet needs to be studied further by using a NLFFF magnetic field model and not just the potential magnetic field. This work supported by the NSF-REU solar physics program at SAO, grant number AGS-1560313 and NASA Grant NNX15AF43G

Twisting solar coronal jet launched at the boundary of an active region

NASA Astrophysics Data System (ADS)

Schmieder, B.; Guo, Y.; Moreno-Insertis, F.; Aulanier, G.; Yelles Chaouche, L.; Nishizuka, N.; Harra, L. K.; Thalmann, J. K.; Vargas Dominguez, S.; Liu, Y.

2013-11-01

Aims: A broad jet was observed in a weak magnetic field area at the edge of active region NOAA 11106 that also produced other nearby recurring and narrow jets. The peculiar shape and magnetic environment of the broad jet raised the question of whether it was created by the same physical processes of previously studied jets with reconnection occurring high in the corona. Methods: We carried out a multi-wavelength analysis using the EUV images from the Atmospheric Imaging Assembly (AIA) and magnetic fields from the Helioseismic and Magnetic Imager (HMI) both on-board the Solar Dynamics Observatory, which we coupled to a high-resolution, nonlinear force-free field extrapolation. Local correlation tracking was used to identify the photospheric motions that triggered the jet, and time-slices were extracted along and across the jet to unveil its complex nature. A topological analysis of the extrapolated field was performed and was related to the observed features. Results: The jet consisted of many different threads that expanded in around 10 minutes to about 100 Mm in length, with the bright features in later threads moving faster than in the early ones, reaching a maximum speed of about 200 km s-1. Time-slice analysis revealed a striped pattern of dark and bright strands propagating along the jet, along with apparent damped oscillations across the jet. This is suggestive of a (un)twisting motion in the jet, possibly an Alfvén wave. Bald patches in field lines, low-altitude flux ropes, diverging flow patterns, and a null point were identified at the basis of the jet. Conclusions: Unlike classical λ or Eiffel-tower-shaped jets that appear to be caused by reconnection in current sheets containing null points, reconnection in regions containing bald patches seems to be crucial in triggering the present jet. There is no observational evidence that the flux ropes detected in the topological analysis were actually being ejected themselves, as occurs in the violent phase of blowout jets; instead, the jet itself may have gained the twist of the flux rope(s) through reconnection. This event may represent a class of jets different from the classical quiescent or blowout jets, but to reach that conclusion, more observational and theoretical work is necessary.

A Case Study in Forensic Seismology: The 1998 Natural Gas Pipeline Explosion Near Carlsbad, New Mexico

NASA Astrophysics Data System (ADS)

Koper, K. D.; Wallace, T. C.; Aster, R. C.

2002-12-01

On August 19, 2000 two seismometer networks in southeastern New Mexico recorded signals from a natural gas pipeline explosion. The explosion killed 12 members of an extended family that had been camping on the banks of a nearby river. Analysis of the particle motion, arrival times, and durations of the seismic signals indicate that three impulsive events occurred with origin times of 11:26:18.8 +/- 1.9, 11:26:43.6 +/- 2.1, and 11:27:01.7 +/- 2.0 (GMT). Each event generated an Rg wave with group velocity of 1.7-2.0 km/s and an air-coupled Rayleigh wave with a group velocity of about 345 m/s. The air-coupled Rayleigh waves had especially large amplitudes because of a geometric waveguide created by an atmospheric temperature inversion at the time of the accident. The first event was due to the explosive blowout of the buried, high-pressure pipeline while the second event was due to the ignition of the vented natural gas. The nature of the third event is unclear, however it was likely created by a secondary ignition. There were also two extended seismic events that were coeval with the first two impulsive events. The first resulted from the pre-ignition venting of the gas and lasted for about 24~s, while the second resulted from the post-ignition roaring of the flames and lasted for about one hour. Many of the source constraints provided by the seismic data were not available from any other investigative technique and so were valuable to a diverse range of parties including the New Mexico State Police, law firms involved in litigation related to the accident, the National Transportation and Safety Board, and the general public. Especially important was the seismically derived time between the blowout and ignition. The 24.0~s lag indicates that the initial rending of the pipe did not cause the ignition and that a more likely source was the nearby campsite, and it also significantly affected the amount of punitive damages the families of the victims were due since the victims were in a state of extreme distress during that period of time.

Rotating Magnetic Structures Associated with a Quasi-circular Ribbon Flare

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Haidong; Jiang, Yunchun; Yang, Jiayan

We present the detection of a small eruption and the associated quasi-circular ribbon flare during the emergence of a bipole occurring on 2015 February 3. Under a fan dome, a sigmoid was rooted in a single magnetic bipole, which was encircled by negative polarity. The nonlinear force-free field extrapolation shows the presence of twisted field lines, which can represent a sigmoid structure. The rotation of the magnetic bipole may cause the twisting of magnetic field lines. An initial brightening appeared at one of the footpoints of the sigmoid, where the positive polarity slides toward a nearby negative polarity field region.more » The sigmoid displayed an ascending motion and then interacted intensively with the spine-like field. This type of null point reconnection in corona led to a violent blowout jet, and a quasi-circular flare ribbon was also produced. The magnetic emergence and rotational motion are the main contributors to the energy buildup for the flare, while the cancellation and collision might act as a trigger.« less

Assessment of impacts and evaluation of restoration methods on areas affected by a well blowout, Naval Petroleum Reserve No. 1, California

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warrick, G.D.; Kato, T.T.; Phillips, M.V.

1996-12-01

In June 1994, an oil well on Naval Petroleum Reserve No. 1 blew-out and crude oil was deposited downwind. After the well was capped, information was collected to characterize the release and to assess effects to wildlife and plants. Oil residue was found up to 13.7 km from the well site, but deposition was relatively light and the oil quickly dried to form a thin crust on the soil surface. Elevated levels of hydrocarbons were found in livers collected from Heermann`s kangaroo rats (Dipodomys heermanni) from the oiled area but polycyclic aromatic hydrocarbons (known carcinogens or mutagens) were not detectedmore » in the livers. Restoration techniques (surface modification and bioremediation) and natural recovery were evaluated within three portions of the oiled area. Herbaceous cover and production, and survival and vigor of desert saltbush (Atriplex polycarpa) were also monitored within each trapping grid.« less

Non-linear theory of a cavitated plasma wake in a plasma channel for special applications and control

NASA Astrophysics Data System (ADS)

Thomas, Johannes; Kostyukov, Igor Yu.; Pronold, Jari; Golovanov, Anton; Pukhov, Alexander

2016-05-01

We introduce a complete semi-analytical model for a cavitated electron wake driven by an electron beam in a radially inhomogeneous plasma. The electron response to the driver, dynamics of electrons in a thin sheath surrounding the cavity, as well as accelerating and focusing fields inside the cavity are calculated in the quasistatic approximation. Our theory holds for arbitrary radial density profiles and reduces to known models in the limit of a homogeneous plasma. A free-propagating blow-out in an evacuated channel experiences longitudinal squeezing, qualitatively the same as observed in particle-in-cell simulations for the laser pulse-driven case [Pukhov et al., Phys. Rev. Lett. 113, 245003 (2014)]. Our model also permits qualitative interpretation of the earlier observed cancellation of the focusing gradient in the cavity [Pukhov et al., Phys. Rev. Lett. 113, 245003 (2014)]. In this work, we show the underlying mechanism that causes the radial fields in the vacuum part of a channel to become defocussing.

Effects of Pollution on Marine Organisms.

PubMed

Mearns, Alan J; Reish, Donald J; Oshida, Philip S; Ginn, Thomas; Rempel-Hester, Mary Ann; Arthur, Courtney; Rutherford, Nicolle; Pryor, Rachel

2015-10-01

This review covers selected 2014 articles on the biological effects of pollutants and human physical disturbances on marine and estuarine plants, animals, ecosystems and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, dredging and disposal, etc. Special emphasis is placed on effects of oil spills and marine debris due in part to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico and the 2011 Japanese tsunami. Several topical areas reviewed in the past (ballast water and ocean acidification) were dropped this year. The focus of this review is on effects, not pollutant fate and transport. There is considerable overlap across subject areas (e.g.some bioaccumulation papers may be cited in other topical categories). Please use keyword searching of the text to locate related but distributed papers. Use this review only as a guide and please consult the original papers before citing them.

Formation of Ultrarelativistic Electron Rings from a Laser-Wakefield Accelerator.

PubMed

Pollock, B B; Tsung, F S; Albert, F; Shaw, J L; Clayton, C E; Davidson, A; Lemos, N; Marsh, K A; Pak, A; Ralph, J E; Mori, W B; Joshi, C

2015-07-31

Ultrarelativistic-energy electron ring structures have been observed from laser-wakefield acceleration experiments in the blowout regime. These electron rings had 170-280 MeV energies with 5%-25% energy spread and ∼10  pC of charge and were observed over a range of plasma densities and compositions. Three-dimensional particle-in-cell simulations show that laser intensity enhancement in the wake leads to sheath splitting and the formation of a hollow toroidal pocket in the electron density around the wake behind the first wake period. If the laser propagates over a distance greater than the ideal dephasing length, some of the dephasing electrons in the second period can become trapped within the pocket and form an ultrarelativistic electron ring that propagates in free space over a meter-scale distance upon exiting the plasma. Such a structure acts as a relativistic potential well, which has applications for accelerating positively charged particles such as positrons.

The Montara Oil Spill: A 2009 Well Blowout in the Timor Sea.

PubMed

Spies, R B; Mukhtasor, M; Burns, K A

2017-07-01

A well on the Montara platform on the Australian continental shelf blew out in August 2009 and spilled oil into the Timor Sea for 74 days. The oil, estimated at as much as 23.5 million L in total volume, spread over a large area of the shelf and eventually into Indonesian waters. This paper documents, through published literature, reports of both Australian and Indonesian governments and observations of coastal residents and fishermen the spread of the oil and attempts to estimate its impact. The lack of observers on the ocean and baseline, pre-spill data on populations of marine organisms, and delays in deploying scientific surveys after the spill severely limited efforts by the Australian government to determine damage in its territorial waters. Biological survey work was not done in Indonesian waters, but coastal residents attested to relatively severe impacts to algal farms. In addition fish landings declined in one port in southwest Timor Island.

Coral communities as indicators of ecosystem-level impacts of the Deepwater Horizon spill

USGS Publications Warehouse

Fisher, Charles R.; Demopoulos, Amanda W.J.; Cordes, Erik E.; Baums, Iliana B.; White, Helen K.; Bourque, Jill R.

2014-01-01

The Macondo oil spill released massive quantities of oil and gas from a depth of 1500 meters. Although a buoyant plume carried released hydrocarbons to the sea surface, as much as half stayed in the water column and much of that in the deep sea. After the hydrocarbons reached the surface, weathering processes, burning, and the use of a dispersant caused hydrocarbon-rich marine snow to sink into the deep sea. As a result, this spill had a greater potential to affect deep-sea communities than had any previous spill. Here, we review the literature on impacts on deep-sea communities from the Macondo blowout and provide additional data on sediment hydrocarbon loads and the impacts on sediment infauna in areas with coral communities around the Macondo well. We review the literature on the genetic connectivity of deep-sea species in the Gulf of Mexico and discuss the potential for wider effects on deep Gulf coral communities.

A Universal Model for Solar Eruptions

NASA Astrophysics Data System (ADS)

Wyper, Peter; Antiochos, Spiro K.; DeVore, C. Richard

2017-08-01

We present a universal model for solar eruptions that encompasses coronal mass ejections (CMEs) at one end of the scale, to coronal jets at the other. The model is a natural extension of the Magnetic Breakout model for large-scale fast CMEs. Using high-resolution adaptive mesh MHD simulations conducted with the ARMS code, we show that so-called blowout or mini-filament coronal jets can be explained as one realisation of the breakout process. We also demonstrate the robustness of this “breakout-jet” model by studying three realisations in simulations with different ambient field inclinations. We conclude that magnetic breakout supports both large-scale fast CMEs and small-scale coronal jets, and by inference eruptions at scales in between. Thus, magnetic breakout provides a unified model for solar eruptions. P.F.W was supported in this work by an award of a RAS Fellowship and an appointment to the NASA Postdoctoral Program. C.R.D and S.K.A were supported by NASA’s LWS TR&T and H-SR programs.

Open-hole fishing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pietrobono, J.T.

1988-01-01

This paper reports on losing equipment in the hole that is one of the most expensive and potentially dangerous things that can go wrong in drilling a well. Drilling must come to a halt until the equipment is recovered, or the hole must be sidetracked. The well also can become hard to control with essential tools out of reach, increasing the risk of a blowout. Fishing, or recovering lost or stuck equipment in the hole, is therefore a critical procedure at any drilling operation. Fishing can be divided into two broad categories: open hole and cased hole. a major differencemore » between the two is timing: open-hole fishing is done as the well is being drilled, whereas cased-hole fishing is performed during production or well workover. Fishing techniques and types of equipment used also vary between the tow. This lesson describes some of the basic techniques and tools used in open-hole fishing-that is, retrieving fish from a hole that is being drilled but is not yet cased.« less

Shear Ram Verification Test Protocol (VTP) Best Practices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lindley, Roy A.; Braun, Joseph C.

A blowout preventer (BOP) is a critical component used on subsea oil and gas wells during drilling, completion, and workover operations on the U. S. outer continental shelf (OCS). The purpose of the BOP is to seal oil and gas wells, and in the case of an emergency well-control event, to prevent the uncontrolled release of hydrocarbons. One of the most important components of the BOP is the hydraulically operated blind shear ram (BSR) that shears drilling-related components, such as drill pipes, casings, tubings, and wire-related tools that may have been placed in the well. In addition to shearing thesemore » components, the BSR must form a seal to keep hydrocarbons within the well bore, even when under the highest well-fluid pressures expected. The purpose of this document is for Argonne National Laboratory (ANL) to provide an independent view, based on current regulations, and best practices for testing and confirming the operability and suitability of BSRs under realistic (or actual) well conditions.« less

Analytical fuel property effects--small combustors

NASA Technical Reports Server (NTRS)

Sutton, R. D.; Troth, D. L.; Miles, G. A.

1984-01-01

The consequences of using broad-property fuels in both conventional and advanced state-of-the-art small gas turbine combustors are assessed. Eight combustor concepts were selected for initial screening, of these, four final combustor concepts were chosen for further detailed analysis. These included the dual orifice injector baseline combustor (a current production 250-C30 engine combustor) two baseline airblast injected modifications, short and piloted prechamber combustors, and an advanced airblast injected, variable geometry air staged combustor. Final predictions employed the use of the STAC-I computer code. This quasi 2-D model includes real fuel properties, effects of injector type on atomization, detailed droplet dynamics, and multistep chemical kinetics. In general, fuel property effects on various combustor concepts can be classified as chemical or physical in nature. Predictions indicate that fuel chemistry has a significant effect on flame radiation, liner wall temperature, and smoke emission. Fuel physical properties that govern atomization quality and evaporation rates are predicted to affect ignition and lean-blowout limits, combustion efficiency, unburned hydrocarbon, and carbon monoxide emissions.

Effects of Pollution on Marine Organisms.

PubMed

Mearns, Alan J; Reish, Donald J; Oshida, Philip S; Morrison, Ann Michelle; Rempel-Hester, Mary Ann; Arthur, Courtney; Rutherford, Nicolle; Pryor, Rachel

2017-10-01

This review covers selected 2016 articles on the biological effects of pollutants and human physical disturbances on marine and estuarine plants, animals, ecosystems and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, dredging and disposal etc. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico. Several topical areas reviewed in the past (ballast water and ocean acidification) were dropped this year. The focus of this review is on effects, not pollutant fate and transport. There is considerable overlap across subject areas (e.g.some bioaccumulation papers may be cited in other topical categories). Please use keyword searching of the text to locate related but distributed papers. Use this review only as a guide and please consult the original papers before citing them.

Effects of Pollution on Marine Organisms.

PubMed

Mearns, Alan J; Reish, Donald J; Oshida, Philip S; Morrison, Ann Michelle; Rempel-Hester, Mary Ann; Arthur, Courtney; Rutherford, Nicolle; Pryor, Rachel

2016-10-01

This review covers selected 2015 articles on the biological effects of pollutants and human physical disturbances on marine and estuarine plants, animals, ecosystems and habitats. The review, based largely on journal articles, covers field and laboratory measurement activities (bioaccumulation of contaminants, field assessment surveys, toxicity testing and biomarkers) as well as pollution issues of current interest including endocrine disrupters, emerging contaminants, wastewater discharges, dredging and disposal, etc. Special emphasis is placed on effects of oil spills and marine debris due largely to the 2010 Deepwater Horizon oil blowout in the Gulf of Mexico. Several topical areas reviewed in the past (ballast water and ocean acidification) were dropped this year. The focus of this review is on effects, not pollutant fate and transport. There is considerable overlap across subject areas (e.g.some bioaccumulation papers may be cited in other topical categories). Please use keyword searching of the text to locate related but distributed papers. Use this review only as a guide and please consult the original papers before citing them.

Experimental study of the effects of secondary air on the emissions and stability of a lean premixed combustor

NASA Technical Reports Server (NTRS)

Roffe, G.; Raman, R. S. V.

1981-01-01

Tests were run using a perforated plate flameholder with a relatively short attached recirculation zone and a vee gutter flameholder with a relatively long attached recirculation zone. Combustor streamlines were traced in cold flow tests at ambient pressure. The amount of secondary air entrainment in the recirculation zones of the flameholders was determined by tracer gas testing at cold flow ambient pressure conditions. Combustion tests were caried out at entrance conditions of 0.5 MPa/630K and emission of NOx, CO and unburned hydrocarbons were measured along with lean stability and flashback limits. The degree of entrainment increases as dilution air injection decreases. Flashback appears to be a function of overall equivalence ratio and resistance to flashback increases with increasing combustor entrance velocity. Lean stability limit appears to be a function of both primary zone and flameholder recirculation zone equivalence ratios and resistance to lean blowout increases with increasing combustor entrance velocity.

SUPERNOVAE AND THEIR EXPANDING BLAST WAVES DURING THE EARLY EVOLUTION OF GALACTIC GLOBULAR CLUSTERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tenorio-Tagle, Guillermo; Silich, Sergiy; Muñoz-Tuñón, Casiana

2015-11-20

Our arguments deal with the early evolution of Galactic globular clusters and show why only a few of the supernovae (SNe) products were retained within globular clusters and only in the most massive cases (M ≥ 10{sup 6} M{sub ⊙}), while less massive clusters were not contaminated at all by SNe. Here, we show that SN blast waves evolving in a steep density gradient undergo blowout and end up discharging their energy and metals into the medium surrounding the clusters. This inhibits the dispersal and the contamination of the gas left over from a first stellar generation. Only the ejecta from well-centeredmore » SNe that evolve into a high-density medium available for a second stellar generation (2SG) in the most massive clusters would be retained. These are likely to mix their products with the remaining gas, eventually leading in these cases to an Fe-contaminated 2SG.« less

Assessment, development, and application of combustor aerothermal models

NASA Technical Reports Server (NTRS)

Holdeman, J. D.; Mongia, H. C.; Mularz, E. J.

1989-01-01

The gas turbine combustion system design and development effort is an engineering exercise to obtain an acceptable solution to the conflicting design trade-offs between combustion efficiency, gaseous emissions, smoke, ignition, restart, lean blowout, burner exit temperature quality, structural durability, and life cycle cost. For many years, these combustor design trade-offs have been carried out with the help of fundamental reasoning and extensive component and bench testing, backed by empirical and experience correlations. Recent advances in the capability of computational fluid dynamics codes have led to their application to complex 3-D flows such as those in the gas turbine combustor. A number of U.S. Government and industry sponsored programs have made significant contributions to the formulation, development, and verification of an analytical combustor design methodology which will better define the aerothermal loads in a combustor, and be a valuable tool for design of future combustion systems. The contributions made by NASA Hot Section Technology (HOST) sponsored Aerothermal Modeling and supporting programs are described.

Booming Muddy Play spells success for Recluse area

DOE Office of Scientific and Technical Information (OSTI.GOV)

Woncik, J.

1968-11-25

The discovery of Bell Creek in Montana in June 1967 and Recluse in Wyoming in July 1967, plus the blowout of an extension to Kitty field in Oct. of 1967 set off the extensive exploratory and development effort. Bell Creek is now the best daily producer in the Rockies with over 50,000 bpd from 315 wells. Recluse makes 21,000 bpd from 80 wells, Kitty 9,000 bpd from 30 wells. Wyoming's Recluse field lies on the NE. shelf of the Powder River Basin. This basin has 14 pays, 13 are Cretaceous, the other Minnelusa Paleozoic Permo-Pennsylvanian. Practically all Cretaceous accumulation andmore » over half of the Minnelusa is stratigraphic. Cumulative production in the Cretaceous in the basin is about one billion bbl of oil. Over 200 million bbl have been produced from the Minnelusa-Tensleep. The Recluse sand deposition of Newcastle Muddy age shows evidence of being a barrier island deposit of marine origin.« less

Impact of automobile restraint device utilization on facial fractures and fiscal implications for plastic surgeons.

PubMed

Adkinson, Joshua M; Murphy, Robert X

2011-05-01

In 2009, the National Highway Traffic Safety Administration projected that 33,963 people would die and millions would be injured in motor vehicle collisions (MVC). Multiple studies have evaluated the impact of restraint devices in MVCs. This study examines longitudinal changes in facial fractures after MVC as result of utilization of restraint devices. The Pennsylvania Trauma Systems Foundation-Pennsylvania Trauma Outcomes Study database was queried for MVCs from 1989 to 2009. Restraint device use was noted, and facial fractures were identified by International Classification of Diseases-ninth revision codes. Surgeon cost data were extrapolated. More than 15,000 patients sustained ≥1 facial fracture. Only orbital blowout fractures increased over 20 years. Patients were 2.1% less likely every year to have ≥1 facial fracture, which translated into decreased estimated surgeon charges. Increased use of protective devices by patients involved in MVCs resulted in a change in incidence of different facial fractures with reduced need for reconstructive surgery.

Macrospicule Jets in On-Disk Coronal Holes

NASA Technical Reports Server (NTRS)

Adams, M. L.; Sterling, A. C.; Moore, R. L.

2014-01-01

We examine the magnetic structure and dynamics of multiple jets found in coronal holes close to or on disk center. All data are from the Atmospheric Imaging Assembly (AIA) and the Helioseismic and Magnetic Imager (HMI) of the Solar Dynamics Observatory (SDO). We report on observations of six jets in an equatorial coronal hole spanning 2011 February 27 and 28. We show the evolution of these jets in AIA 193 A, examine the magnetic field configuration, and postulate the probable trigger mechanism of these events. We recently reported on another jet in the same coronal hole on 2011 February 27, approximately 13:04 Universal Time (Adams et al 2014, Astrophysical Journal, 783: 11); this jet is a previously-unrecognized variety of blowout jet. In this variety, the reconnection bright point is not made by interchange reconnection of initially-closed erupting field in the base of the jet with ambient open field. Instead, there is a miniature filament-eruption flare arcade made by internal reconnection of the legs of the erupting field.

Flame Stability in a Trapped-Vortex Spray-Combustor

NASA Astrophysics Data System (ADS)

Chakka, P.; Mancilla, P. C.; Acharya, S.

1999-11-01

Flame stabilization mechanisms in a Trapped-Vortex (TV) cavity is investigated experimentally and computationally in the current research. The TV-cavity is placed coaxially in the combustor and the flame is maintained through injection of liquid fuel spray and air from the inside face of the afterbody. This concept was introduced by Roquemore and company of Wright-Patterson AFB for gaseous fuel injection into the cavity and is extended for liquid fuel sprays in the current research. The flame holding capability of the TV-cavity is studied for different equivalence ratios of the secondary injection and overall Lean Blow-Out (LBO) limits are presented for different primary and secondary flow rates. The interaction and mixing of the main flow with the secondary vortex flow is investigated through the Laser Doppler Velocimetry measurements taken through a quartz window near the cavity. Also, temperature distribution through IR measurements and pressure fluctuations inside the chamber are presented for complete performance analysis of the TV cavity combustor.

Modelling the long-term evolution of worst-case Arctic oil spills.

PubMed

Blanken, Hauke; Tremblay, Louis Bruno; Gaskin, Susan; Slavin, Alexander

2017-03-15

We present worst-case assessments of contamination in sea ice and surface waters resulting from hypothetical well blowout oil spills at ten sites in the Arctic Ocean basin. Spill extents are estimated by considering Eulerian passive tracers in the surface ocean of the MITgcm (a hydrostatic, coupled ice-ocean model). Oil in sea ice, and contamination resulting from melting of oiled ice, is tracked using an offline Lagrangian scheme. Spills are initialized on November 1st 1980-2010 and tracked for one year. An average spill was transported 1100km and potentially affected 1.1 million km 2 . The direction and magnitude of simulated oil trajectories are consistent with known large-scale current and sea ice circulation patterns, and trajectories frequently cross international boundaries. The simulated trajectories of oil in sea ice match observed ice drift trajectories well. During the winter oil transport by drifting sea ice is more significant than transport with surface currents. Copyright © 2017 Elsevier Ltd. All rights reserved.

What Will Classroom Teachers Do With Shared Research Results?

NASA Astrophysics Data System (ADS)

Passow, M. J.; Weissel, J. K.; Cormier, M.; Newman, K. R.

2005-12-01

Scientists are passionate about the research problems they investigate, and wish to share their discoveries as widely as possible. Similarly, classroom teachers who are passionate about their subject can better foster student learning. One way to enhance such passions involves bringing teachers and scientists together to discuss cutting-edge discoveries and develop curricular materials based on the respective strengths of educators and investigators. Our presentation describes one example of this approach based on research about gas blowout structures offshore Virginia and North Carolina. Methane venting processes along continental margins may have important climatic, geotechnical, hazard, and resource implications. In 2000, shipboard surveys documented that large structures offshore VA-NC resulted from massive gas expulsion. Gas appears to be trapped in shelf edge deltas and stresses resulting from downslope creep is favoring its release. Scientists undertook a new expedition in 2004 to determine if there is present-day discharge of methane-rich fluids through the floors or walls of the blowouts or whether these seepage sites are relict features, and to gain insight into the origin of the vented methane. In July 2005, 12 teachers from New York and New Jersey met with the co-PIs (Weissel and Cormier), graduate student (Newman), and educational specialist (Passow) over a 2-day workshop to learn about how scientific problems are identified, how a research cruise is organized, what was learned through the measurements and analysis, and what might be possible significant impacts from such understandings. Based on what they learned, participants began development of classroom activities, Internet-based investigations, and constructed-response assessment items utilizing data and concepts from the project and other sources. The resulting curriculum units are designed for use in middle and high school chemistry, physics, earth science, and technology courses. Curricular units include "Using Real-Life Problems to Learn Scientific Principles," "Mapping the Unseen Floors," "Landslide or Not," and a board game based on conducting a scientific research cruise. Materials are available through www.earth2class.org. Over the following academic year, participants will continue to develop instructional materials, field-test them, and provide peer training through in-district and regional professional development opportunities. The scientists and educational specialist will provide support to ensure scientific accuracy and pedagogical soundness. The project will utilize DLESE as an additional effective dissemination and evaluation mechanism. In these ways, the scientists and core of educators may be able to share these discoveries with hundreds of teachers and thousands of students.

High-quality electron beams from beam-driven plasma accelerators by wakefield-induced ionization injection.

PubMed

Martinez de la Ossa, A; Grebenyuk, J; Mehrling, T; Schaper, L; Osterhoff, J

2013-12-13

We propose a new and simple strategy for controlled ionization-induced trapping of electrons in a beam-driven plasma accelerator. The presented method directly exploits electric wakefields to ionize electrons from a dopant gas and capture them into a well-defined volume of the accelerating and focusing wake phase, leading to high-quality witness bunches. This injection principle is explained by example of three-dimensional particle-in-cell calculations using the code OSIRIS. In these simulations a high-current-density electron-beam driver excites plasma waves in the blowout regime inside a fully ionized hydrogen plasma of density 5×10(17)cm-3. Within an embedded 100  μm long plasma column contaminated with neutral helium gas, the wakefields trigger ionization, trapping of a defined fraction of the released electrons, and subsequent acceleration. The hereby generated electron beam features a 1.5 kA peak current, 1.5  μm transverse normalized emittance, an uncorrelated energy spread of 0.3% on a GeV-energy scale, and few femtosecond bunch length.

Dispersant Effectiveness, In-Situ Droplet Size Distribution and ...

EPA Pesticide Factsheets

This report summarizes two projects covered under an Interagency Agreement between the Bureau of Safety and Environmental Enforcement (BSEE) and the U.S. Environmental Protection Agency (EPA) in collaboration with the Bedford Institute of Oceanography, Department of Fisheries and Oceans Canada (BIO DFO), New Jersey Institute of Technology (NJIT) and Dalhousie University. Both projects dovetail together in addressing the ability to differentiate physical from chemical dispersion effectiveness using dispersed oil simulations within a flume tank for improving forensic response monitoring tools. This report is split into separateTasks based upon the two projects funded by BSEE: 1) Dispersant Effectiveness, In-Situ Droplet Size Distribution and Numerical Modeling to Assess Subsurface Dispersant Injection as a Deepwater Blowout Oil Spill Response Option. 2) Evaluation of Oil Fluorescence Characteristics to Improve Forensic Response Tools. This report summarizes 2 collaborative projects funded through an Interagency Agreement with DOI BSEE and a Cooperative Agreement with DFO Canada. BSEE required that the projects be combined into one report as they are both covered under the one Interagency Agreement. Task B (Fluorescence of oils) is an SHC 3.62 FY16 product.

Close games versus blowouts: Optimal challenge reinforces one's intrinsic motivation to win.

PubMed

Meng, Liang; Pei, Guanxiong; Zheng, Jiehui; Ma, Qingguo

2016-12-01

When immersed in intrinsically motivating activities, individuals actively seek optimal challenge, which generally brings the most satisfaction as they play hard and finally win. To better simulate real-life scenarios in the controlled laboratory setting, a two-player online StopWatch (SW) game was developed, whose format is similar to that of a badminton tournament. During the game, a male opponent played by a confederate ensured that the same-sex participant paired with him won both matches, one with a wide margin (the lack of challenge condition) and another with a narrow one (the optimal challenge condition). Electrophysiological data were recorded during the entire experiment. An enlarged Stimulus-preceding negativity (SPN) was observed in the optimal challenge condition, indicating a more concentrated anticipatory attention toward the feedback and a stronger intrinsic motivation during close games. Thus, this study provided original neural evidence for predictions of Self-determination theory (SDT) and Flow theory, and confirmed and emphasized the significant role of optimal challenge in promoting one's intrinsic motivation to win. Copyright © 2016 Elsevier B.V. All rights reserved.

Non-linear theory of a cavitated plasma wake in a plasma channel for special applications and control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thomas, Johannes, E-mail: thomas@tp1.uni-duesseldorf.de; Pronold, Jari; Pukhov, Alexander

2016-05-15

We introduce a complete semi-analytical model for a cavitated electron wake driven by an electron beam in a radially inhomogeneous plasma. The electron response to the driver, dynamics of electrons in a thin sheath surrounding the cavity, as well as accelerating and focusing fields inside the cavity are calculated in the quasistatic approximation. Our theory holds for arbitrary radial density profiles and reduces to known models in the limit of a homogeneous plasma. A free-propagating blow-out in an evacuated channel experiences longitudinal squeezing, qualitatively the same as observed in particle-in-cell simulations for the laser pulse-driven case [Pukhov et al., Phys.more » Rev. Lett. 113, 245003 (2014)]. Our model also permits qualitative interpretation of the earlier observed cancellation of the focusing gradient in the cavity [Pukhov et al., Phys. Rev. Lett. 113, 245003 (2014)]. In this work, we show the underlying mechanism that causes the radial fields in the vacuum part of a channel to become defocussing.« less

Turbulence, combustion, pollutant, and stability characterization of a premixed, step combustor

NASA Technical Reports Server (NTRS)

Ganji, A. T.; Sawyer, R. F.

1980-01-01

A two dimensional combustion tunnel was constructed to study a lean premixed turbulent propane/air flame stablized behind a rearward facing step. Studied were: (1) the existence and importance of large coherent structures in turbulent reacting and nonreacting free shear layers behind the steps; (2) the effect of inlet temperature and reference velocity on combustion efficiency; (3) CO, NO2 and NO sub x production in the flame; and (4) the blowout and upstream propagation of the flame. In the ranges studied, the large coherent structures dominated both the reacting and the nonreacting free shear layers behind the step. The growth of the vortices and the propagation of the flamer were intimately linked. Vortex pairing was observed to be one of the mechanisms for introduction of fresh reactants into the shear layer and growth of the shear layer. Probe composition measurements of the flame showed that, in the recirculation zone, the reaction was above 99 percent complete, CO and unburnt hydrocarbons were above the equilibrium level NO sub x concentration was far below the equilibrium level and NO2 comprised a negligible fraction of NO sub x.

A detailed examination of the LWFA in the Self-Guided Nonlinear Blowout Regime for 15-100 Joule Lasers

NASA Astrophysics Data System (ADS)

Davidson, Asher; Tableman, Adam; Yu, Peicheng; An, Weiming; Tsung, Frank; Mori, Warren; Lu, Wei; Fonseca, Ricardo

2017-10-01

We examine scaling laws for LWFA in the regime nonlinear, self-guided regime in detail using the quasi-3D version of the particle-in-cell code OSIRIS. We find that the scaling laws continue to work well when we fix the normalized laser amplitude while reducing plasma density. It is further found that the energy gain for fixed laser energy can be improved by shortening the pulse length until self-guiding almost no longer occurs and that the energy gain can be optimized by using lasers with asymmetric longitudinal profiles. We find that when optimized, a 15 J laser may yield particle energies as high as 5.3 GeV without the need of any external guiding. Detailed studies for optimizing energy gains from 30 J and 100 J lasers will also presented which indicate that energies in excess of 10 GeV can be possible in the near term without the need for external guiding. This work is supported by the NSF and DOE.

δ(13)C and δ(15)N in deep-living fishes and shrimps after the Deepwater Horizon oil spill, Gulf of Mexico.

PubMed

Quintana-Rizzo, Ester; Torres, Joseph J; Ross, Steve W; Romero, Isabel; Watson, Kathleen; Goddard, Ethan; Hollander, David

2015-05-15

The blowout of the Deepwater Horizon (DWH) drill-rig produced a surface oil layer, dispersed micro-droplets throughout the water column, and sub-surface plumes. We measured stable carbon and nitrogen isotopes in mesopelagic fishes and shrimps in the vicinity of DWH collected prior to, six weeks after, and one year after the oil spill (2007, 2010 and 2011). In 2010, the year of the oil spill, a small but significant depletion of δ(13)C was found in two mesopelagic fishes (Gonostoma elongatum and Chauliodus sloani) and one shrimp (Systellaspis debilis); a significant δ(15)N enrichment was identified in the same shrimp and in three fish species (G. elongatum, Ceratoscopelus warmingii, and Lepidophanes guentheri). The δ(15)N change did not suggest a change of trophic level, but did indicate a change in diet. The data suggest that carbon from the Deepwater Horizon oil spill was incorporated into the mesopelagic food web of the Gulf of Mexico. Copyright © 2015 Elsevier Ltd. All rights reserved.

Major Accidents (Gray Swans) Likelihood Modeling Using Accident Precursors and Approximate Reasoning.

PubMed

Khakzad, Nima; Khan, Faisal; Amyotte, Paul

2015-07-01

Compared to the remarkable progress in risk analysis of normal accidents, the risk analysis of major accidents has not been so well-established, partly due to the complexity of such accidents and partly due to low probabilities involved. The issue of low probabilities normally arises from the scarcity of major accidents' relevant data since such accidents are few and far between. In this work, knowing that major accidents are frequently preceded by accident precursors, a novel precursor-based methodology has been developed for likelihood modeling of major accidents in critical infrastructures based on a unique combination of accident precursor data, information theory, and approximate reasoning. For this purpose, we have introduced an innovative application of information analysis to identify the most informative near accident of a major accident. The observed data of the near accident were then used to establish predictive scenarios to foresee the occurrence of the major accident. We verified the methodology using offshore blowouts in the Gulf of Mexico, and then demonstrated its application to dam breaches in the United Sates. © 2015 Society for Risk Analysis.

A Coronal Hole Jet Observed with Hinode and the Solar Dynamics Observatory

NASA Technical Reports Server (NTRS)

Young, Peter H.; Muglach, Karin

2014-01-01

A small blowout jet was observed at the boundary of the south coronal hole on 2011 February 8 at around 21:00 UT. Images from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO) revealed an expanding loop rising from one footpoint of a compact, bipolar bright point. Magnetograms from the Helioseismic Magnetic Imager (HMI) on board SDO showed that the jet was triggered by the cancelation of a parasitic positive polarity feature near the negative pole of the bright point. The jet emission was present for 25 mins and it extended 30 Mm from the bright point. Spectra from the EUV Imaging Spectrometer on board Hinode yielded a temperature and density of 1.6 MK and 0.9-1.7 × 10( exp 8) cu cm for the ejected plasma. Line-of-sight velocities reached up to 250 km/s. The density of the bright point was 7.6 × 10(exp 8) cu cm, and the peak of the bright point's emission measure occurred at 1.3 MK, with no plasma above 3 MK.

Sacrifice and extracranial reconstruction of the common or internal carotid artery in advanced head and neck carcinoma: Review and meta-analysis.

PubMed

Bäck, Leif J J; Aro, Katri; Tapiovaara, Laura; Vikatmaa, Pirkka; de Bree, Remco; Fernández-Álvarez, Verónica; Kowalski, Luiz P; Nixon, Iain J; Rinaldo, Alessandra; Rodrigo, Juan P; Robbins, K Thomas; Silver, Carl E; Snyderman, Carl H; Suárez, Carlos; Takes, Robert P; Ferlito, Alfio

2018-06-01

Sacrifice and reconstruction of the carotid artery in cases of head and neck carcinoma with invasion of the common or internal carotid artery is debated. We conducted a systematic search of electronic databases and provide a review and meta-analysis. Of the 72 articles identified, 24 met the inclusion criteria resulting in the inclusion of 357 patients. The overall perioperative 30-day mortality was 3.6% (13/357). Permanent cerebrovascular complications occurred in 3.6% (13/357). Carotid blowout episodes were encountered in 1.4% (5/357). The meta-regression analysis showed a significant difference in 1-year overall survival between reports published from 1981-1999 (37.0%) and 2001-2016 (65.4%; P = .02). This review provides evidence that sacrifice with extracranial reconstruction of common or internal carotid artery in selected patients with head and neck carcinoma may improve survival with acceptable complication rates. However, all of the published literature is retrospective involving selected series and, therefore, precludes determining the absolute effectiveness of the surgery. © 2018 Wiley Periodicals, Inc.

Overpressure Prediction From Seismic Data: Implications on Drilling Safety

NASA Astrophysics Data System (ADS)

Osinowo, O. O.; Oladunjoye, M. A.; Olayinka, A. I.

2007-12-01

High rate of sediment influx into the Niger Delta via river Niger coupled with high rate of basin subsidence, very thick clayey members of Agbada and Akata Formations as well as prevailing presence of growth faults had been identified as the main factors responsible for overpressure generation and preservation in the Niger Delta basin. Analysis of porosity dependent parameters such as interval transit times and interval velocities derived from the seismic records of a field in the Western Niger Delta revealed the presence of overpressured formation at depth of 8670 feet, which is the top of the overpressured zone. The plot of interval transit times against depth gave a positive deflection from normal at the region of overpressure while interval velocity plot gave negative deflection; the ratio of this deviation in both cases is as high as 1.52. Pressure gradient in the upper, normally pressured part of the field was determined to be 0.465 psi/ft., which is within the established normal pressure gradient range in Niger Delta, while the abnormal formation pressure gradient in the overpressured region was determined to be 0.96 psi/ft., and this is also within the published abnormal pressure gradient range of 0.71 to 1.1 psi/ft. in Niger Delta. Formation fracture pressure gradients were determined from the formation pressure information to be 0.66psi/ft. in the upper part of the field and 1.2psi/ft. in the overpressured horizon. Mud weight window (MWW); mud density range necessary to prevent formation kick without initiating hydraulic fracturing was determined to be 10.2 to 12.5lbm/gal in the upper part of the field and 22.1 to 22.63lbm/gal in the overpressured horizon. MWW is indispensable for the selection of the mud pump type, capacity, pumping rate and mud densities at different formation pressure regimes. Overpressure prediction is also requisite for drilling program design, casing design as well as rig capacity choice before spudding. It is necessary to reduce well construction risk, save drilling hour as well as cut down drilling cost. If adequate predictions are not taken however, drilling hazards known as blowout may occur. Blowout, an uncontrollable flow of formation fluid into the well has made oil exploration and exploitation activities in Niger Delta, Southern Nigeria, a curse for the people rather than a blessing because considerable numbers of wells blew out during well construction activities, hence the characteristic oil spill which had degraded the environment, making fishing operation, a source of livelihood of the people difficult. Therefore the need for overpressure prediction as a guide for safe drilling, especially in unfamiliar exploration environments.

Understanding the build-up of SMBH and Galaxies

NASA Astrophysics Data System (ADS)

Carrera, Francisco; Georgakakis, Antonis; Ueda, Yoshihiro; Akylas, Thanassis; Lanzuisi, Giorgio; Castello, N.

2015-09-01

One of the main open questions in modern Astrophysics is understanding the coupled growth of supermassive black holes by accretion and their host galaxies via star formation, from their peak at redshifts z~ 1-4 to the present time. The generic scenario proposed involves an early phase of intense black hole growth that takes place behind large obscuring columns of inflowing dust and gas clouds. It is postulated that this is followed by a blow-out stage during which some form of AGN feedback controls the fate of the interstellar medium and hence, the evolution of the galaxy. X-rays are essential for testing this scenario as they uniquely probe AGN at both the early heavily obscured stage and the later blow-out phase. X-ray spectral analysis can identify the smoking gun evidence of heavily obscured black hole growth (e.g. intense iron Kalpha line). It therefore provides the most robust method for compiling clean samples of deeply shrouded AGN with well-defined selection functions and unbiased determinations of their intrinsic properties (accretion luminosity, obscuring column). X-rays are also the best window for studying in detail AGN feedback. This process ultimately originates in the innermost regions close to the supermassive black hole and is dominated, in terms of energy and mass flux, by highly ionised material that remains invisible at other wavelengths. The most important epoch for investigating the relation between AGN and galaxies is the redshift range z~1-4, when most black holes and stars we see in the present-day Universe were put in place. Unfortunately, exhaustive efforts with current high-energy telescopes only scrape the tip of the iceberg of the most obscured AGN population. Moreover, Xray studies of the incidence, nature and energetics of AGN feedback are limited to the local Universe. The Athena observatory will provide the technological leap required for a breakthrough in our understanding of AGN and galaxy evolution at the heyday of the Universe. The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

Understanding the build-up of supermassive black holes and galaxies

NASA Astrophysics Data System (ADS)

Carrera, Francisco; Ueda, Yoshihiro; Georgakakis, Antonis

2016-07-01

One of the main open questions in modern Astrophysics is understanding the coupled growth of supermassive black holes by accretion and their host galaxies via star formation, from their peak at redshifts z~ 1-4 to the present time. The generic scenario proposed involves an early phase of intense black hole growth that takes place behind large obscuring columns of inflowing dust and gas clouds. It is postulated that this is followed by a blow-out stage during which some form of AGN feedback controls the fate of the interstellar medium and hence, the evolution of the galaxy. X-rays are essential for testing this scenario as they uniquely probe AGN at both the early heavily obscured stage and the later blow-out phase. X-ray spectral analysis can identify the smoking gun evidence of heavily obscured black hole growth (e.g. intense iron Kalpha line). It therefore provides the most robust method for compiling clean samples of deeply shrouded AGN with well-defined selection functions and unbiased determinations of their intrinsic properties (accretion luminosity, obscuring column). X-rays are also the best window for studying in detail AGN feedback. This process ultimately originates in the innermost regions close to the supermassive black hole and is dominated, in terms of energy and mass flux, by highly ionisedmaterial that remains invisible at other wavelengths. The most important epoch for investigating the relation between AGN and galaxies is the redshift range z~1-4, when most black holes and stars we see in the present-day Universe were put in place. Unfortunately, exhaustive efforts with current high-energy telescopes only scrape the tip of the iceberg of the most obscured AGN population. Moreover, Xray studies of the incidence, nature and energetics of AGN feedback are limited to the local Universe. The Athena observatory will provide the technological leap required for a breakthrough in our understanding of AGN and galaxy evolution at the heyday of the Universe. The excellent survey capabilities of Athena/WFI (effective area, angular resolution, field of view) will allow to measure the incidence of feedback in the shape of warm absorbers and Ultra Fast Outflows among the general population of AGN, as well as to complete the census of black hole growth by detecting and characterising significant samples of the most heavily obscured (including Compton thick) AGN, to redshifts z~3-4. The outstanding spectral throughput and resolution of Athena/X-IFU will permit measuring the energetics of those outflows to assess their influence on their host galaxies. The demographics of the heavily obscured and outflowing populations relative to their hosts are fundamental for understanding how major black hole growth events relate to the build-up of galaxies.

X-ray emission from the Wolf-Rayet bubble NGC 6888 - II. XMM-Newton EPIC observations

NASA Astrophysics Data System (ADS)

Toalá, J. A.; Guerrero, M. A.; Chu, Y.-H.; Arthur, S. J.; Tafoya, D.; Gruendl, R. A.

2016-03-01

We present deep XMM-Newton European Photon Imaging Camera observations of the Wolf-Rayet (WR) bubble NGC 6888 around the star WR 136. The complete X-ray mapping of the nebula confirms the distribution of the hot gas in three maxima spatially associated with the caps and north-west blowout hinted at by previous Chandra observations. The global X-ray emission is well described by a two-temperature optically thin plasma model (T1 = 1.4 × 106 K, T2 = 8.2 × 106 K) with a luminosity of LX = 7.8 × 1033 erg s-1 in the 0.3-1.5 keV energy range. The rms electron density of the X-ray-emitting gas is estimated to be ne = 0.4 cm-3. The high-quality observations presented here reveal spectral variations within different regions in NGC 6888, which allowed us for the first time to detect temperature and/or nitrogen abundance inhomogeneities in the hot gas inside a WR nebula. One possible explanation for such spectral variations is that the mixing of material from the outer nebula into the hot bubble is less efficient around the caps than in other nebular regions.

Reconstruction of Orbital Floor With Auricular Concha.

PubMed

Seven, Ergin; Tellioglu, Ali Teoman; Inozu, Emre; Ozakpinar, Hulda Rifat; Horoz, Ugur; Eryilmaz, Avni Tolga; Karamursel, Sebat

2017-10-01

Orbital floor fractures of varying sizes commonly occur after orbital injuries and remain a serious challenge. Serious complications of such fractures include enopthalmos, restriction of extraocular movement, and diplopia. There is a dearth of literature that can be applied widely, easily, and successfully in all such situations, and therefore there is no consensus on the treatment protocol of this pathology yet. Autogenous grafts and alloplastic and allogenic materials with a wide variety of advantages and disadvantages have been discussed. The value of preoperative and postoperative ophthalmological examination should be standard of care in all orbital fracture patients. An ideal reconstructed orbital floor fracture should accelerate the restoration of orbital function with acceptable cosmetic results. Management parameters of orbital fractures such as timing of surgery, incision type, and implant materials, though widely discussed, remain controversial. In this study, 55 patients with orbital floor fractures surgically reconstructed with conchal cartilage grafts between 2008 and 2014 were retrospectively evaluated. Complications and long-time follow-up visit results have been reported with clinical and radiographic findings. The aim of this study was to present the authors' clinical experiences of reconstruction of blow-out fractures with auricular conchal graft and to evaluate the other materials available for use.

[Advances in the field of surgical therapy of strabismus (author's transl)].

PubMed

Aichmair, H

1979-04-27

During the past 10 years the surgical treatment of strabismus has received different new impulses. Two fundamental novelties in this field have been reported and three not unimportant contributions towards the facilitation of, or improvement in therapy: Cüppers described a method to improve and/or eliminate the dynamic squinting angle in cases of ocular nystagmus by the so-called "Fadenoperation" and Aichmair demonstrated the possibility of re-establishing the function of a traumatically paralyzed abducens muscle by means of muscular neurotisation. Aichmair and Abel discovered in a comparative study that there is no necessity to bandage patients after a squint operation; this is of especial importance in small children as there need no longer be any fear of the postoperative binocular bandage. Aichmair and Fries demonstrated a simple method for the precise measurement of the volume of implantates to eliminate enophthalmus after blow-out fractures; this helps the surgeon to avoid over- or undercorrection. They stressed, furthermore, the importance of the right shape of the implantate. de Decker published a new method of tucking of the superior oblique and of recession of the inferior oblique that facilitates the operation and at the same time enables more accurate dosation.

Ergonomic evaluation of ten single-channel pipettes.

PubMed

Lichty, Monica G; Janowitz, Ira L; Rempel, David M

2011-01-01

Repetitive pipetting is a task that is associated with work-related musculoskeletal disorders of the hand and arm. The purpose of this study was to evaluate the usability and ergonomic performance of commercially available pipettes as determined by user ratings and objective measurements. Participants were laboratory technicians and scientists at the Lawrence Berkeley National Laboratory with experience performing pipetting tasks. Twenty-one experienced pipette users completed a standardized pipetting task with 5 manual and 5 electronic pipettes. After using each pipette, the user rated it for attributes of comfort and usability. Although no single pipette was rated significantly better than all of the others for every attribute tested, some significant differences were found between pipettes. The Rainin Pipet-Lite received the highest overall quality score among manual pipettes, while the Thermo Scientific Finnpipette Novus was the top-ranked electronic pipette. Features correlated with greater hand and arm comfort were lower tip ejection force, lower blowout force, and pipette balance in the hand. The findings, when considered with participant comments, provide insights into desirable pipette features and emphasize the value of user testing and the importance of the interactions between task, workplace layout, and pipette design. © 2011 - IOS Press and the authors. All rights reserved

Experimental clean combustor program, phase 1. [aircraft exhaust/gas analysis - gas turbine engines

NASA Technical Reports Server (NTRS)

Roberts, R.; Peduzzi, A.; Vitti, G. E.

1975-01-01

A program of screening three low emission combustors for conventional takeoff and landing, by testing and analyzing thirty-two configurations is presented. Configurations were tested that met the emission goals at idle operating conditions for carbon monoxide and for unburned hydrocarbons (emission index values of 20 and 4, respectively). Configurations were also tested that met a smoke number goal of 15 at sea-level take-off conditions. None of the configurations met the goal for oxides of nitrogen emissions at sea-level take-off conditions. The best configurations demonstrated oxide of nitrogen emission levels that were approximately 61 percent lower than those produced by the JT9D-7 engine, but these levels were still approximately 24 percent above the goal of an emission index level of 10. Additional combustor performance characteristics, including lean blowout, exit temperature pattern factor and radial profile, pressure loss, altitude stability, and altitude relight characteristics were documented. The results indicate the need for significant improvement in the altitude stability and relight characteristics. In addition to the basic program for current aircraft engine combustors, seventeen combustor configurations were evaluated for advanced supersonic technology applications. The configurations were tested at cruise conditions, and a conceptual design was evolved.

Direct Laser Acceleration in Laser Wakefield Accelerators

NASA Astrophysics Data System (ADS)

Shaw, J. L.; Froula, D. H.; Marsh, K. A.; Joshi, C.; Lemos, N.

2017-10-01

The direct laser acceleration (DLA) of electrons in a laser wakefield accelerator (LWFA) has been investigated. We show that when there is a significant overlap between the drive laser and the trapped electrons in a LWFA cavity, the accelerating electrons can gain energy from the DLA mechanism in addition to LWFA. The properties of the electron beams produced in a LWFA, where the electrons are injected by ionization injection, have been investigated using particle-in-cell (PIC) code simulations. Particle tracking was used to demonstrate the presence of DLA in LWFA. Further PIC simulations comparing LWFA with and without DLA show that the presence of DLA can lead to electron beams that have maximum energies that exceed the estimates given by the theory for the ideal blowout regime. The magnitude of the contribution of DLA to the energy gained by the electron was found to be on the order of the LWFA contribution. The presence of DLA in a LWFA can also lead to enhanced betatron oscillation amplitudes and increased divergence in the direction of the laser polarization. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

Non-grey dimming events of KIC 8462852 from GTC spectrophotometry

NASA Astrophysics Data System (ADS)

Deeg, Hans J.; Alonso, Roi; Nespral, David; Boyajian, Tabetha S.

2018-02-01

We report ground-based spectrophotometry of KIC 8462852 obtained during its first dimming events since the end of the Kepler mission. The dimmings show a clear colour signature and are deeper in visual blue than in red wavelengths. The wavelength dependency of the flux loss can be described with an absorption Ångström coefficient of 2.19 ± 0.45, which is compatible with absorption by optically thin dust with particle sizes of the order of 0.0015 to 0.15 μm. These particles would be smaller than is required to be resistant against blow-out by radiation pressure when close to the star. During occultation events, these particles must be replenished from a comoving body on time-scales of days. If dust is indeed the source of the dimming events of KIC 8462852, deeper dimming events should show more neutral colours, as is expected from optically thick absorbers. The individual reduced spectra of the target and reference stars are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/610/L12

Major common bile duct injury and risk of litigation: a surgeon's perspective.

PubMed

Berney, Christophe R

2012-11-01

Risk for a lawsuit for medical malpractice has unfortunately become part of physicians' daily professional activities, with a blowout in indemnity insurance premiums, especially in high-risk medical specialties. Common bile duct injury following laparoscopic cholecystectomy is a well-recognized and feared complication for surgeons because of its associated morbidity, and it also ranks among the leading sources of medical malpractice claims against surgeons in the world. The purpose of this article is to raise awareness within the medical community and in particular among specialist surgeons on the important threat they could be facing in terms of litigation in the event of an adverse surgical outcome following such a commonly performed procedure. There is a real need for open debate on this concerning topic, as the fear of lawsuits and exorbitant malpractice premiums are pushing a substantial number of medical professionals to practice defensive medicine, reflected by the avoidance of performing certain procedures or treating high-risk patients perceived to have higher litigation rates, or simply walking away from their current practices, creating a chronic shortage of specialized doctors in certain surgical areas. Copyright © 2012 Elsevier Inc. All rights reserved.

Diverter bop system and method for a bottom supported offshore drilling rig

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roche, J. R.; Alexander, G. G.; Carbaugh, W. L.

1985-06-25

A system and method for installing a fluid flow controller and telescoping spools beneath an offshore bottom supported drilling rig rotary table is disclosed. Upper and lower telescoping spools are provided for initially connecting a Diverter/BOP convertible fluid flow controller between structural casing in the well and a permanent housing beneath the drilling rig rotary table. Clamp means are provided for clamping the rig vent line to an opening in the housing wall of the fluid flow controller during drilling of the borehole through the structural casing in preparation for setting and cementing the conductor casing. In that mode, themore » system is adapted as a diverter system. After the well is drilled for the conductor casing and the conductor casing is cemented and cut off at its top, a mandrel is fitted at the top of the conductor casing to which the lower end of the lower spool may be connected. The system may be used in this configuration as a diverter system, or after removal of the vent line and connection of a kill line to the housing outlet, the system may be used as a low pressure blowout preventer system.« less

CUSP-SHAPED STRUCTURE OF A JET OBSERVED BY IRIS AND SDO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, Yuzong; Zhang, Jun, E-mail: yuzong@nao.cas.cn, E-mail: zjun@nao.cas.cn

2017-01-01

On 2014 August 29, the trigger and evolution of a cusp-shaped jet were captured in detail at 1330 Å by the Interface Region Imaging Spectrograph . At first, two neighboring mini-prominences arose in turn from the low solar atmosphere and collided with a loop-like system over them. The collisions between the loop-like system and the mini-prominences lead to the blowout, and then a cusp-shaped jet formed with a spire and an arch-base. In the spire, many brightening blobs originating from the junction between the spire and the arch-base moved upward in a rotating manner and then in a straight line inmore » the late phase of the jet. In the arch-base, dark and bright material simultaneously tracked in a fan-like structure, and the majority of the material moved along the fan's threads. At the later phase of the jet's evolution, bidirectional flows emptied the arch-base, while downflows emptied the spire, thus making the jet entirely vanish. The extremely detailed observations in this study shed new light on how magnetic reconnection alters the inner topological structure of a jet and provides a beneficial complement for understanding current jet models.« less

Synthetic Modeling of Autonomous Learning with a Chaotic Neural Network

NASA Astrophysics Data System (ADS)

Funabashi, Masatoshi

We investigate the possible role of intermittent chaotic dynamics called chaotic itinerancy, in interaction with nonsupervised learnings that reinforce and weaken the neural connection depending on the dynamics itself. We first performed hierarchical stability analysis of the Chaotic Neural Network model (CNN) according to the structure of invariant subspaces. Irregular transition between two attractor ruins with positive maximum Lyapunov exponent was triggered by the blowout bifurcation of the attractor spaces, and was associated with riddled basins structure. We secondly modeled two autonomous learnings, Hebbian learning and spike-timing-dependent plasticity (STDP) rule, and simulated the effect on the chaotic itinerancy state of CNN. Hebbian learning increased the residence time on attractor ruins, and produced novel attractors in the minimum higher-dimensional subspace. It also augmented the neuronal synchrony and established the uniform modularity in chaotic itinerancy. STDP rule reduced the residence time on attractor ruins, and brought a wide range of periodicity in emerged attractors, possibly including strange attractors. Both learning rules selectively destroyed and preserved the specific invariant subspaces, depending on the neuron synchrony of the subspace where the orbits are situated. Computational rationale of the autonomous learning is discussed in connectionist perspective.

Continuous pumping of steam into the wells of the Camp Pirital deposit in Venezuela

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lanfranchi, E.A.

The Campo Pirital deposit was opened in 1956. The maximal oil extraction occured in 1961 and by 1965, it was reduced. Steam pumping was begun in 1965. The extraction rose to 731 cubic meters per day by May, 1967 and by 1976, the extraction again fell. The introduction of a test plan for continuous steam pumping into the sand collectors was begun in July, 1976. Loose carbonate, finely grained sandstones of pale gray and gray to green color, interlayered by clay and carbonate lutites, are typical deposits for this region. The test plan is a model of 9 wells (onemore » pumping (N) well and eight operational (E) wells). The operational wells are located at a distance of 34.4 to 187 meters from the pumping well. At the end of five years of use of the test plan, the following positive results may be discussed: the flow rates of the wells remained constant, no steam blowout was noted in the wells, the front of heat is shifted to the upper part of the structure and so on. Therefore, the test project is recommended for expansion and three new installations will be positioned near the first.« less

Taming of a Wild Research Well in Yellowstone National Park during November 1992

USGS Publications Warehouse

Fournier, Robert O.; Moore, Michael M.

2008-01-01

Much of our current understanding of Yellowstone's geothermal areas comes from research drilling by the USGS during 1967 and 1968. Thirteen wells were drilled in thermal areas around the park. Scientists collected waters and rocks, measured temperatures and pressures and performed other tests to characterize the shallow subsurface at Yellowstone. Most wells were plugged and abandoned, but a few were left open for future scientific tests and sampling. One of those wells, the Y8, was located at Biscuit Basin, 2 miles north of Old Faithful. In November 1992, a valve at the ground surface failed, leading to a blowout, an uncontrolled eruption of steam and hot water. The USGS and Yellowstone National Park worked with a drilling contractor to control the flow and plug the well. The lead scientist, Robert Fournier, used video taken by the drilling contractor, Tonto Services, to create this fascinating 28-minute-long film. It is followed by a short news story by CNN, also from November 1992. Fifteen years later, we felt that the video was of sufficient scientific and historical interest that it was worth publishing as a USGS Open-file report, where it can be accessed into the future. Enjoy!

Hubble Space Telescope imaging of Eta Carinae

NASA Technical Reports Server (NTRS)

Hester, J. J.; Westphal, James A.; Light, Robert M.; Currie, Douglas G.; Groth, Edward J.

1991-01-01

New high spatial resolution observations of the material around Eta Carinae, obtained with the Hubble Space Telescope Wide Field/Planetary Camera, are presented. The star Eta Carinae is one of the most massive and luminous stars in the Galaxy, and has been episodically expelling significant quantities of gas over the last few centuries. The morphology of the bright central nebulosity (the homunculus) indicates that it is a thin shell with very well defined edges, and is clumpy on 0.2 arcsec (about 10 to the 16th cm) scales. An extension to the northeast of the star (NN/NS using Walborn's 1976 nomenclature) appears to be a stellar jet and its associated bow shock. The bow shock is notable for an intriguing series of parallel linear features across its face. The S ridge and the W arc appear to be part of a 'cap' of emission located to the SW and behind the star. Together, the NE jet and the SW cap suggest that the symmetry axis for the system runs NE-SW rather than SE-NW, as previously supposed. Overall, the data indicate that the material around the star may represent an oblate shell with polar blowouts, rather than a bipolar flow.

Shape memory alloy actuated accumulator for ultra-deepwater oil and gas exploration

NASA Astrophysics Data System (ADS)

Patil, Devendra; Song, Gangbing

2016-04-01

As offshore oil and gas exploration moves further offshore and into deeper waters to reach hydrocarbon reserves, it is becoming essential for the industry to develop more reliable and efficient hydraulic accumulators to supply pressured hydraulic fluid for various control and actuation operations, such as closing rams of blowout preventers and controlling subsea valves on the seafloor. By utilizing the shape memory effect property of nitinol, which is a type of shape memory alloy (SMA), an innovative SMA actuated hydraulic accumulator prototype has been developed and successfully tested at Smart Materials and Structure Laboratory at the University of Houston. Absence of gas in the developed SMA accumulator prototype makes it immune to hydrostatic head loss caused by water depth and thus reduces the number of accumulators required in deep water operations. Experiments with a feedback control have demonstrated that the proposed SMA actuated accumulator can provide precisely regulated pressurized fluids. Furthermore the potential use of ultracapacitors along with an embedded system to control the electric power supplied to SMA allows this accumulator to be an autonomous device for deployment. The developed SMA accumulator will make deepwater oil extraction systems more compact and cost effective.

Oceanic methane hydrate: The character of the Blake Ridge hydrate stability zone, and the potential for methane extraction

USGS Publications Warehouse

Max, M.D.; Dillon, William P.

1998-01-01

Oceanic methane hydrates are mineral deposits formed from a crystalline 'ice' of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment's strength both by 'freezing' the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation.Oceanic methane hydrates are mineral sits formed from a crystalline `ice' of methane and water in sea-floor sediments (buried to less than about 1 km) in water depths greater than about 500 m; economic hydrate deposits are probably restricted to water depths of between 1.5 km and 4 km. Gas hydrates increase a sediment's strength both by `freezing' the sediment and by filling the pore spaces in a manner similar to water-ice in permafrost. Concentrated hydrate deposits may be underlain by significant volumes of methane gas, and these localities are the most favourable sites for methane gas extraction operations. Seismic reflection records indicate that trapped gas may blow-out naturally, causing large-scale seafloor collapse. In this paper, we consider both the physical properties and the structural integrity of the hydrate stability zone and the associated free gas deposits, with special reference to the Blake Ridge area, SE US offshore, in order to help establish a suitable framework for the safe, efficient, and economic recovery of methane from oceanic gas hydrates. We also consider the potential effects of the extraction of methane from hydrate (such as induced sea-floor faulting, gas venting, and gas-pocket collapse). We assess the ambient pressure effect on the production of methane by hydrate dissociation, and attempt to predict the likelihood of spontaneous gas flow in a production situation.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freifeld, Barry M.; Oldenburg, Curtis M.; Jordan, Preston

Introduction Motivation The 2015-2016 Aliso Canyon/Porter Ranch natural gas well blowout emitted approximately 100,000 tonnes of natural gas (mostly methane, CH 4) over four months. The blowout impacted thousands of nearby residents, who were displaced from their homes. The high visibility of the event has led to increased scrutiny of the safety of natural gas storage at the Aliso Canyon facility, as well as broader concern for natural gas storage integrity throughout the country. Federal Review of Well Integrity In April of 2016, the U.S. Department of Energy (DOE), in conjunction with the U.S. Department of Transportation (DOT) through themore » Pipeline and Hazardous Materials Safety Administration (PHMSA), announced the formation of a new Interagency Task Force on Natural Gas Storage Safety. The Task Force enlisted a group of scientists and engineers at the DOE National Laboratories to review the state of well integrity in natural gas storage in the U.S. The overarching objective of the review is to gather, analyze, catalogue, and disseminate information and findings that can lead to improved natural gas storage safety and security and thus reduce the risk of future events. The “Protecting our Infrastructure of Pipelines and Enhancing Safety Act of 2016’’ or the ‘‘PIPES Act of 2016,’’which was signed into law on June 22, 2016, created an Aliso Canyon Natural Gas Leak Task Force led by the Secretary of Energy and consisting of representatives from the DOT, Environmental Protection Agency (EPA), Department of Health and Human Services, Federal Energy Regulatory Commission (FERC), Department of Commerce and the Department of Interior. The Task Force was asked to perform an analysis of the Aliso Canyon event and make recommendations on preventing similar incidents in the future. The PIPES Act also required that DOT/PHMSA promulgate minimum safety standards for underground storage that would take effect within two years. Background on the DOE National Laboratories Well Integrity Work Group One of the primary areas that the Task Force is studying is integrity of natural gas wells at storage facilities. The DOE Office of Fossil Energy (FE) took the lead in this area and asked scientists and engineers from the National Energy Technology Laboratory (NETL), Lawrence Livermore National Laboratory (LLNL), Sandia National Laboratories (SNL), and Lawrence Berkeley National Laboratory (LBNL)) to form a Work Group to address this area. This Work Group is an expansion of the original “Lab Team” comprising scientists and engineers from SNL, LLNL, and LBNL which was formed to support the State of California’s response to the Aliso Canyon incident and operated under the Governor of California’s Aliso Canyon Emergency Order (1/6/2016). The Lab Team played a key role in advising the State of California’s Department of Conservation (DOC) in its oversight of SoCalGas during and after the incident.« less

Experimental and Computational Study of Trapped Vortex Combustor Sector Rig With Tri-Pass Diffuser

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Shouse, D. T.; Roquernore, W. M.; Burrus, D. L.; Duncan, B. S.; Ryder, R. C.; Brankovic, A.; Liu, N.-S.; Gallagher, J. R.; Hendricks, J. A.

2004-01-01

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL modes of combustion. The present work describes the operational principles of the TVC, and extends diffuser velocities toward choked flow and provides system performance data. Performance data include EINOx results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable compared to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ballering, Nicholas P.; Rieke, George H.; Gáspár, András, E-mail: ballerin@email.arizona.edu

Observations of debris disks allow for the study of planetary systems, even where planets have not been detected. However, debris disks are often only characterized by unresolved infrared excesses that resemble featureless blackbodies, and the location of the emitting dust is uncertain due to a degeneracy with the dust grain properties. Here, we characterize the Spitzer Infrared Spectrograph spectra of 22 debris disks exhibiting 10 μm silicate emission features. Such features arise from small warm dust grains, and their presence can significantly constrain the orbital location of the emitting debris. We find that these features can be explained by themore » presence of an additional dust component in the terrestrial zones of the planetary systems, i.e., an exozodiacal belt. Aside from possessing exozodiacal dust, these debris disks are not particularly unique; their minimum grain sizes are consistent with the blowout sizes of their systems, and their brightnesses are comparable to those of featureless warm debris disks. These disks are in systems of a range of ages, though the older systems with features are found only around A-type stars. The features in young systems may be signatures of terrestrial planet formation. Analyzing the spectra of unresolved debris disks with emission features may be one of the simplest and most accessible ways to study the terrestrial regions of planetary systems.« less

Digital implementation of the TF30-P-3 turbofan engine control

NASA Technical Reports Server (NTRS)

Cwynar, D. S.; Batterton, P. G.

1975-01-01

The standard hydromechanical control modes for TF30-P-3 engine were implemented on a digital process control computer. Programming methods are described, and a method is presented to solve stability problems associated with fast response dynamic loops contained within the exhaust nozzle control. A modification of the exhaust nozzle control to provide for either velocity or position servoactuation systems is discussed. Transient response of the digital control was evaluated by tests on a real time hybrid simulation of the TF30-P-3 engine. It is shown that the deadtime produced by the calculation time delay between sampling and final output is more significant to transient response than the effects associated with sampling rate alone. For the main fuel control, extended update and calculation times resulted in a lengthened transient response to throttle bursts from idle to intermediate with an increase in high pressure compressor stall margin. Extremely long update intervals of 250 msec could be achieved without instability. Update extension for the exhaust nozzle control resulted in a delayed response of the afterburner light-off detector and exhaust nozzle overshoot with resulting fan oversuppression. Long update times of 150 msec caused failure of the control due to a false indication by the blowout detector.

Carbon in weathered ordinary chondrites from Roosevelt County

NASA Technical Reports Server (NTRS)

Ash, R. D.; Pillinger, C. T.

1993-01-01

A suite of Roosevelt County ordinary chondrites of known terrestrial age have been analyzed for carbon content and isotopic composition. Initial results indicate that significant carbon contamination is evident only in samples with a terrestrial age greater than 40 ka. These samples are of weathering grade D and E and contain three times more carbon than the less weathered samples. The soil in which they were preserved has a carbon content of ca. 1.5 percent. Over 200 meteorites have been recovered from a series of soil depleted areas of New Mexico and West Texas. Most have been recovered from blowouts near Clovis in Roosevelt County (RC) on the high plains of New Mexico. The mineralogical and petrologic Al effects of weathering upon these samples have been studied previously and show that the degree of weathering is largely depend ant upon the terrestrial residence time. The study was undertaken to determine the effects of prolonged exposure to the soil and climate of Roosevelt County upon ordinary chondrites in the hope that this will enable a better understanding of the problems associated with the collection of meteoritic falls. A suite of ten grade 4 to 6 H, L, and LL ordinary chondrites were analyzed for carbon content and isotopic composition.

Large-eddy simulation study of oil/gas plumes in stratified fluid with cross current

NASA Astrophysics Data System (ADS)

Yang, Di; Xiao, Shuolin; Chen, Bicheng; Chamecki, Marcelo; Meneveau, Charles

2017-11-01

Dynamics of the oil/gas plume from a subsea blowout are strongly affected by the seawater stratification and cross current. The buoyant plume entrains ambient seawater and lifts it up to higher elevations. During the rising process, the continuously increasing density difference between the entrained and ambient seawater caused by the stable stratification eventually results in a detrainment of the entrained seawater and small oil droplets at a height of maximum rise (peel height), forming a downward plume outside the rising inner plume. The presence of a cross current breaks the plume's axisymmetry and causes the outer plume to fall along the downstream side of the inner plume. The detrained seawater and oil eventually fall to a neutral buoyancy level (trap height), and disperse horizontally to form an intrusion layer. In this study, the complex plume dynamics is investigated using large-eddy simulation (LES). Various laboratory and field scale cases are simulated to explore the effect of cross current and stratification on the plume dynamics. Based on the LES data, various turbulence statistics of the plume are systematically quantified, leading to some useful insights for modeling the mean plume dynamics using integral plume models. This research is made possible by a RFP-V Grant from The Gulf of Mexico Research Initiative.

Evidence of sulfate-dependent anaerobic methane oxidation ...

EPA Pesticide Factsheets

The rapid development of unconventional gas resources has been accompanied by an increase in public awareness regarding the potential effects of drilling operations on drinking water sources. Incidents have been reported involving blowouts (e.g., Converse County, WY; Lawrence Township, PA; Aliso Canyon, CA) and home/property explosions (e.g., Bainbridge Township, OH; Dimock, PA; Huerfano County, CO) caused by methane migration in the subsurface within areas of natural gas development. We evaluated water quality characteristics in the northern Raton Basin of Colorado and documented the response of the Poison Canyon aquifer system several years after upward migration of methane gas occurred from the deeper Vermejo Formation coalbed production zone. Results show persistent secondary water quality impacts related to the biodegradation of methane. We identify four distinct characteristics of groundwater methane attenuation in the Poison Canyon aquifer: (i) consumption of methane and sulfate and production of sulfide and bicarbonate, (ii) methane loss coupled to production of higher-molecular-weight (C2+) gaseous hydrocarbons, (iii) patterns of 13C enrichment and depletion in methane and dissolved inorganic carbon, and (iv) a systematic shift in sulfur and oxygen isotope ratios of sulfate, indicative of microbial sulfate reduction. We also show that the biogeochemical response of the aquifer system has not mobilized naturally occurring trace metals, including arsenic,

Pulsar Wind Bubble Blowout from a Supernova

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blondin, John M.; Chevalier, Roger A., E-mail: blondin@ncsu.edu

For pulsars born in supernovae, the expansion of the shocked pulsar wind nebula is initially in the freely expanding ejecta of the supernova. While the nebula is in the inner flat part of the ejecta density profile, the swept-up, accelerating shell is subject to the Rayleigh–Taylor instability. We carried out two- and three-dimensional simulations showing that the instability gives rise to filamentary structure during this initial phase but does not greatly change the dynamics of the expanding shell. The flow is effectively self-similar. If the shell is powered into the outer steep part of the density profile, the shell ismore » subject to a robust Rayleigh–Taylor instability in which the shell is fragmented and the shocked pulsar wind breaks out through the shell. The flow is not self-similar in this phase. For a wind nebula to reach this phase requires that the deposited pulsar energy be greater than the supernova energy, or that the initial pulsar period be in the ms range for a typical 10{sup 51} erg supernova. These conditions are satisfied by some magnetar models for Type I superluminous supernovae. We also consider the Crab Nebula, which may be associated with a low energy supernova for which this scenario applies.« less

Mandibular reconstruction in the radiated patient: the role of osteocutaneous free tissue transfers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duncan, M.J.; Manktelow, R.T.; Zuker, R.M.

1985-12-01

This paper discusses our experience with the second metatarsal and iliac crest osteocutaneous transfers for mandibular reconstruction. The prime indication for this type of reconstruction was for anterior mandibular defects when the patient had been previously resected. Midbody to midbody defects were reconstructed with the metatarsal and larger defects with the iliac crest. In most cases, an osteotomy was done to create a mental angle. The evaluation of speech, oral continence, and swallowing revealed good results in all patients unless lip or tongue resection compromised function. Facial contour was excellent in metatarsal reconstructions. The iliac crest cutaneous flap provided amore » generous supply of skin for both intraoral reconstruction and external skin coverage but tended to be bulky, particularly when used in the submental area. Thirty three of 36 flaps survived completely. Flap losses were due to anastomosis thrombosis (1), pedicle compression (1), and pedicle destruction during exploration for suspected carotid blowout (1). Ninety three percent of bone junctions developed a solid bony union despite the mandible having had a full therapeutic dose of preoperative radiation. Despite wound infections in 8 patients, and intraoral dehiscence with bone exposure in 12 patients, all but one of these transfers went on to good bony union without infection in the bone graft.« less

Analytic model of electron self-injection in a plasma wakefield accelerator in the strongly nonlinear bubble regime

NASA Astrophysics Data System (ADS)

Yi, Sunghwan; Khudik, Vladimir; Shvets, Gennady

2012-10-01

We study self-injection into a plasma wakefield accelerator in the blowout (or bubble) regime, where the bubble evolves due to background density inhomogeneities. To explore trapping, we generalize an analytic model for the wakefields inside the bubble [1] to derive expressions for the fields outside. With this extended model, we show that a return current in the bubble sheath layer plays an important role in determining the trapped electron trajectories. We explore an injection mechanism where bubble growth due to a background density downramp causes reduction of the electron Hamiltonian in the co-moving frame, trapping the particle in the dynamically deepening potential well [2]. Model calculations agree quantitatively with PIC simulations on the bubble expansion rate required for trapping, as well as the range of impact parameters for which electrons are trapped. This is an improvement over our previous work [3] using a simplified spherical bubble model, which ignored the fields outside of the bubble and hence overestimated the expansion rate required for trapping. [4pt] [1] W. Lu et al., Phys. Plasmas 13, 056709 (2006).[0pt] [2] S. Kalmykov et al., Phys. Rev. Lett 103, 135004 (2009).[0pt] [3] S.A. Yi et al., Plasma Phys. Contr. Fus. 53, 014012 (2011).

Vulnerability Assessment of a Coastal Dune System at São Francisco do Sul Island, Santa Catarina, Brazil

NASA Astrophysics Data System (ADS)

Alquini, Fernanda; Bertoni, Duccio; Sarti, Giovanni; Ciccarelli, Daniela; Pozzebon, Alessandro; Ferreira de Melo Júnior, João Carlos; Voos Vieira, Celso

2016-10-01

In this paper a Coastal Dune Vulnerability Index (CDVI) has been applied on a beach located in the eastern side of Sao Francisco do Sul Island (Brazil). The aim of this study is to assess the vulnerability of a coastal dune system and to identify the areas that result most sensitive to environmental changes. The CDVI has been applied along six transects traced out on two sectors that have been selected based on dune characteristics: Zone A is characterized by well developed parabolic dunes, whereas Zone B is characterized by transverse dunes. The analysis involved 51 quantitative and qualitative variables, divided into five groups: geomorphological dune system condition, marine influence, Aeolian effect, vegetation condition and human effect. The total CDVI was computed as the unweighted average of the partial vulnerability indices. In summary, the total vulnerability can be classified as medium: the geomorphological factor must be monitored at Grande beach, in particular the blowouts in Zone A and the frontal dune retreat in Zone B. The results of the study confirm that the management of coastal areas might be improved using a tool such as the CDVI, which can be easily applied on a regular basis to take under control the factors that mostly affect the evolution of the site.

Simulation of the landfall of the Deepwater Horizon oil on the shorelines of the Gulf of Mexico.

PubMed

Boufadel, Michel C; Abdollahi-Nasab, Ali; Geng, Xiaolong; Galt, Jerry; Torlapati, Jagadish

2014-08-19

We conducted simulations of oil transport from the footprint of the Macondo Well on the water surface throughout the Gulf of Mexico, including deposition on the shorelines. We used the U.S. National Oceanic Atmospheric Administration (NOAA) model General NOAA Operational Modeling Environment (GNOME) and the same parameter values and input adopted by NOAA following the Deepwater Horizon (DWH) blowout. We found that the disappearance rate of oil off the water surface was most likely around 20% per day based on satellite-based observations of the disappearance rate of oil detected on the sea surface after the DWH wellhead was capped. The simulations and oil mass estimates suggest that the mass of oil that reached the shorelines was between 10,000 and 30,000 tons, with an expected value of 22,000 tons. More than 90% of the oil deposition occurred on the Louisiana shorelines, and it occurred in two batches. Simulations revealed that capping the well after 2 weeks would have resulted in only 30% of the total oil depositing on the shorelines, while capping after 3 weeks would have resulted in 60% deposition. Additional delay in capping after 3 weeks would have averted little additional shoreline oiling over the ensuing 4 weeks.

Discovery of a Pulsar Wind Nebula Candidate in the Cygnus Loop

NASA Technical Reports Server (NTRS)

Katsuda, Satoru; Tsunemi, Hiroshi; Mori, Koji; Uchida, Hiroyuki; Petre, Robert; Yamada, Shin'ya; Tamagawa, Toru

2012-01-01

We report on a discovery of a diffuse nebula containing a point-like source in the southern blowout region of the Cygnus Loop supernova remnant, based on Suzaku and XMM-Newton observations. The X-ray spectra from the nebula and the point-like source are well represented by an absorbed power-law model with photon indices of 2.2+/-0.1 and 1.6+/-0.2, respectively. The photon indices as well as the flux ratio of F(sub nebula)/F(sub point-like) approx. 4 lead us to propose that the system is a pulsar wind nebula, although pulsations have not yet been detected. If we attribute its origin to the Cygnus Loop supernova, then the 0.5-8 keV luminosity of the nebula is computed to be 2.1x10(exp 31)(d/540pc)(exp 2)ergss/2, where d is the distance to the Loop. This implies a spin-down loss-energy E approx. 2.6x10(exp 35)(d/540pc)(exp 2)ergs/s. The location of the neutron star candidate, approx.2deg away from the geometric center of the Loop, implies a high transverse velocity of approx.1850(theta/2deg)(d/540pc)(t/10kyr)/k/s assuming the currently accepted age of the Cygnus Loop.

The nuclear superbubble of NGC 3079

NASA Technical Reports Server (NTRS)

Veilleux, S.; Cecil, G.; Bland-Hawthorn, J.; Tully, R. B.; Filippenko, A. V.; Sargent, W. L. W.

1994-01-01

We have used the Hawaii Imaging Fabry-Perot Interferometer (HIFI) at the CFH 3.6 m telescope to map H-alpha + (N II) lambda-lambda 6548, 6583 emission-line profiles across the entire edge-on, nearby SBc galaxy NGC 3079, with resolution 70 km/s and subarcsecond sampling. Blue and red long-slit spectra were obtained with the Double Spectrograph on the Palomar 5 meter telescope to provide additional emission-line diagnostics. A spectacular, line emitting bubble of diameter 13 sec (approximately 1.1 kpc) is observed immediately east of the nucleus. Its unusual gaseous excitation (e.g., (N II) lambda(6583)/H-alpha greater than 1) suggests that shocks are important. Extremely violent gas motions that range over 2000 km/s are detected across the bubble and diametrically opposite on the west side of the nucleus. Nonrotational motions are also found in the inner galaxy disk. The superbubble of NGC 3079 is the most powerful example known of a wind-blown bubble, and an excellent laboratory to study wind dynamics. The dimensions and energies of the bubble imply that is likely to be in the blowout phase and partially ruptured. The predicted rate of kinetic energy output from the central starburst appears sufficient to power most of this outflow. It is possible that a central active galactic nucleus also contributes to the outflow.

Chemical dispersants can suppress the activity of natural oil-degrading microorganisms

PubMed Central

Kleindienst, Sara; Seidel, Michael; Ziervogel, Kai; Grim, Sharon; Loftis, Kathy; Harrison, Sarah; Malkin, Sairah Y.; Perkins, Matthew J.; Field, Jennifer; Sogin, Mitchell L.; Dittmar, Thorsten; Passow, Uta; Medeiros, Patricia M.; Joye, Samantha B.

2015-01-01

During the Deepwater Horizon oil well blowout in the Gulf of Mexico, the application of 7 million liters of chemical dispersants aimed to stimulate microbial crude oil degradation by increasing the bioavailability of oil compounds. However, the effects of dispersants on oil biodegradation rates are debated. In laboratory experiments, we simulated environmental conditions comparable to the hydrocarbon-rich, 1,100 m deep plume that formed during the Deepwater Horizon discharge. The presence of dispersant significantly altered the microbial community composition through selection for potential dispersant-degrading Colwellia, which also bloomed in situ in Gulf deep waters during the discharge. In contrast, oil addition to deepwater samples in the absence of dispersant stimulated growth of natural hydrocarbon-degrading Marinobacter. In these deepwater microcosm experiments, dispersants did not enhance heterotrophic microbial activity or hydrocarbon oxidation rates. An experiment with surface seawater from an anthropogenically derived oil slick corroborated the deepwater microcosm results as inhibition of hydrocarbon turnover was observed in the presence of dispersants, suggesting that the microcosm findings are broadly applicable across marine habitats. Extrapolating this comprehensive dataset to real world scenarios questions whether dispersants stimulate microbial oil degradation in deep ocean waters and instead highlights that dispersants can exert a negative effect on microbial hydrocarbon degradation rates. PMID:26553985

Oil release from Macondo well MC252 following the Deepwater Horizon accident.

PubMed

Griffiths, Stewart K

2012-05-15

Oil flow rates and cumulative discharge from the BP Macondo Prospect well in the Gulf of Mexico are calculated using a physically based model along with wellhead pressures measured at the blowout preventer (BOP) over the 86-day period following the Deepwater Horizon accident. Parameters appearing in the model are determined empirically from pressures measured during well shut-in and from pressures and flow rates measured the preceding day. This methodology rigorously accounts for ill-characterized evolution of the marine riser, installation and removal of collection caps, and any erosion at the wellhead. The calculated initial flow rate is 67,100 stock-tank barrels per day (stbd), which decays to 54,400 stbd just prior to installation of the capping stack and subsequent shut-in. The calculated cumulative discharge is 5.4 million stock-tank barrels, of which 4.6 million barrels entered the Gulf. Quantifiable uncertainties in these values are -9.3% and +7.5%, yielding a likely total discharge in the range from 4.9 to 5.8 million barrels. Minimum and maximum credible values of this discharge are 4.6 and 6.2 million barrels. Alternative calculations using the reservoir and sea-floor pressures indicate that any erosion within the BOP had little affect on cumulative discharge.

Geopressure modeling from petrophysical data: An example from East Kalimantan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herkommer, M.A.

1994-07-01

Localized models of abnormal formation pressure (geopressure) are important economic and safety tools frequently used for well planning and drilling operations. Simplified computer-based procedures have been developed that permit these models to be developed more rapidly and with greater accuracy. These techniques are broadly applicable to basins throughout the world where abnormal formation pressures occur. An example from the Attaka field of East Kalimantan, southeast Asia, shows how geopressure models are developed. Using petrophysical and engineering data, empirical correlations between observed pressure and petrophysical logs can be created by computer-assisted data-fitting techniques. These correlations serve as the basis for modelsmore » of the geopressure. By performing repeated analyses on wells at various locations, contour maps on the top of abnormal geopressure can be created. Methods that are simple in their development and application make the task of geopressure estimation less formidable to the geologist and petroleum engineer. Further, more accurate estimates can significantly improve drilling speeds while reducing the incidence of stuck pipe, kicks, and blowouts. In general, geopressure estimates are used in all phases of drilling operations: To develop mud plans and specify equipment ratings, to assist in the recognition of geopressured formations and determination of mud weights, and to improve predictions at offset locations and geologically comparable areas.« less

Generation and measurement of velocity bunched ultrashort bunch of pC charge

NASA Astrophysics Data System (ADS)

Lu, X. H.; Tang, C. X.; Li, R. K.; To, H.; Andonian, G.; Musumeci, P.

2015-03-01

In this paper, we discuss the velocity compression in a short rf linac of an electron bunch from a rf photoinjector operated in the blowout regime. Particle tracking simulations shows that with a beam charge of 2 pC an ultrashort bunch duration of 16 fs can be obtained at a tight longitudinal focus downstream of the linac. A simplified coherent transition radiation (CTR) spectrum method is developed to enable the measurement of ultrashort (sub-50 fs) bunches at low bunch energy (5 MeV) and low bunch charges (<10 pC ). In this method, the ratio of the radiation energy selected by two narrow bandwidth filters is used to estimate the bunch length. The contribution to the coherent form factor of the large transverse size of the bunch suppresses the radiation signal significantly and is included in the analysis. The experiment was performed at the UCLA Pegasus photoinjector laboratory. The measurement results show bunches of sub-40 fs with 2 pC of charge well consistent with the simulation using actual experimental conditions. These results open the way to the generation of ultrashort bunches with time-duration below 10 fs once some of the limitations of the setup (rf phase jitter, amplitude instability and low field in the gun limited by breakdown) are corrected.

Natural versus Urban dunes along the Emilia-Romagna coast, Northern Adriatic (Italy)

NASA Astrophysics Data System (ADS)

Corbau, Corinne; Simeoni, Umberto

2014-05-01

Beach-dune interaction models can be precious tools for land managers and policymakers. However, if the models are inaccurate, land use policies may be designed based on false pretences or assumptions leading to poor land management, long-term erosion and sustainability issues, and increased difficulties in maintaining the dynamic coastal systems. From the literature, it appears that even the most reliable beach-dunes interactions models are not applicable to all coastal systems (Short and Hesp, 1982; Psuty, 1988; Sherman and Bauer, 1993). The study aims to identify the morphological evolution of the Emilia-Romagna coastal dunes according to its natural and "human" characteristics and to classify groups of dunes with similar evolutionary patterns. The coastal area consists essentially of 130 km of low sandy coast, interrupted by vast lagoon areas, harbor jetties and numerous hard coastal defense structures that were built during the first half of the 20th century to protect the Emilia-Romagna coast against erosion. Today about 57% of the littoral is protected by hard defenses, which have modified the morphodynamic characteristics of the beach without inverting the negative coastal evolution's trend. From recent aerial photographs (2011), 62 coastal dunes have been identified and mapped. Furthermore, the dune analysis shows a variability of the "physical characteristics" of coastal-dune systems along the Emilia-Romagna coast. The dune height varies from 1 to 7 meters, the width of the beach and of the active dunes range respectively from 10 to 150 m and from 10 to 65 m. Three main factors may explain the variability of the "physical characteristics": 1- Firstly the frontal dunes may be of different states according to the classification of Hesp (2002) since they correspond to incipient foredunes, well-developed foredunes, blowouts, residual foredunes as well as reactivated relict foredunes, 2- This could also be related to a different orientation of the coastline and foredune's line to the dominant onshore winds and, 3- Human impacts may also explain this variability since most of the dune-beach systems of Emilia-Romagna are characterized by important anthropogenic features that do not adequately describe beach-foredune interactions. A factor analysis of the coastal dunes has allowed formulating hypotheses about their evolutionary trends according to the importance and interference of factors, both natural and anthropic, acting on the beach-dune system. Four groups of dunes have been identified corresponding to natural dunes, semi-anthropic dunes with major natural features, semi-anthropic dunes with major anthropic feature and "urban" dunes. Furthermore, while human activities impede the formation and development of new incipient dunes, other human activities favor the conservation and development of the human-altered foredunes. Hesp, P., 2002: Foredunes and blowouts: initiation, geomorphology and dynamics, Geomorphology, 245-268. Psuty, N. P. 1988. Sediment budget and dune/beach interaction. Journal of Coastal Research Special Issue 3: 1-4. Sherman, D. J., and B. O. Bauer. 1993. Dynamics of beach-dune systems. Progress in Physical Geography 17 (4): 413-447 Short, A. D., and P. A. Hesp. 1982. Wave, beach and dune interactions in South Eastern Australia. Marine Geology 48: 259-284.

HSCT Sector Combustor Hardware Modifications for Improved Combustor Design

NASA Technical Reports Server (NTRS)

Greenfield, Stuart C.; Heberling, Paul V.; Moertle, George E.

2005-01-01

An alternative to the stepped-dome design for the lean premixed prevaporized (LPP) combustor has been developed. The new design uses the same premixer types as the stepped-dome design: integrated mixer flameholder (IMFH) tubes and a cyclone swirler pilot. The IMFH fuel system has been taken to a new level of development. Although the IMFH fuel system design developed in this Task is not intended to be engine-like hardware, it does have certain characteristics of engine hardware, including separate fuel circuits for each of the fuel stages. The four main stage fuel circuits are integrated into a single system which can be withdrawn from the combustor as a unit. Additionally, two new types of liner cooling have been designed. The resulting lean blowout data was found to correlate well with the Lefebvre parameter. As expected, CO and unburned hydrocarbons emissions were shown to have an approximately linear relationship, even though some scatter was present in the data, and the CO versus flame temperature data showed the typical cupped shape. Finally, the NOx emissions data was shown to agree well with a previously developed correlation based on emissions data from Configuration 3 tests performed at GEAE. The design variations of the cyclone swirler pilot that were investigated in this study did not significantly change the NOx emissions from the baseline design (GEAE Configuration 3) at supersonic cruise conditions.

Modeling of the Plume Development Phase of the Shoemaker-Levy 9 Comet Impact

NASA Astrophysics Data System (ADS)

Palotai, Csaba J.; Korycansky, D.; Deming, D.; Harrington, J.

2008-09-01

We present a progress report on our numerical simulations of the plume blowout and flight/splash phases of the Shoemaker-Levy 9 (SL9) comet impact into Jupiter's atmosphere. For this project we have modified the ZEUS-MP/2 three-dimensional hydrodynamic model (Hayes et al. ApJ.SS. 165. 174-183, 2006) to be suitable for Jovian atmospheric simulations. To initialize our model we map the final state of high-resolution SL9 impact simulations of Korycansky et al. (ApJ 646. 642-652, 2006) onto our larger, stationary grid. In the current phase of the research we investigate how the dynamical chaos in the impact model affects simulations of the subsequent phases. We adapt the atmospheric radiation model from the 2D splash calculation of Deming and Harrington (ApJ 561. 455-467, 2001) to calculate realistic wavelength-dependent lightcurves and low-resolution spectra. Our goal is to compare synthetic images created from model output to the data taken by the Hubble Space Telescope of plumes on the limb of Jupiter during the impacts of various SL9 fragments (Hammel et al. Science 267. 1288-1296, 1995). Details of the model, validation of the code, and results of our latest simulations will be presented. This material is based on work supported by National Science Foundation Grant No. 0307638 and National Aeronautics and Space Administration Grant No. NNG 04GQ35G .

Numerical Simulations Of The Impact Of Comet Shoemaker-Levy 9: Plume Development

NASA Astrophysics Data System (ADS)

Palotai, Csaba J.; Korycansky, D.; Deming, D.; Harrington, J.; Reese, C.

2007-10-01

We present results of our three-dimensional, hydrodynamic simulations of the impact of comet Shoemaker-Levy 9 (SL9) into the atmosphere of Jupiter. In the current phase of the research we focus on the plume blowout and splashback phases of the SL9 event. We have modified the Zeus-MP/2 model (Hayes et al. 2006) to be suitable for our investigation, adding a Jovian atmospheric profile, Tillotson equation of state for the impactor, and the Coriolis terms. As an initial condition of our high-resolution simulations we use the energy deposition profile taken from the SL9 impact modeling of Korycansky et al. (2006). The effects of the Coriolis force during the shockwave propagation are tested through sensitivity tests. The viscosity in the splash model is adjusted until the outer part of the plume re-entry shock matches the expanding infrared rings (McGregor et al. 1996). The molecular viscosity being well-known, this will place a strong constraint on the Jovian eddy viscosity. We add radiative terms from previous 2D splash calculation of Deming and Harrington (2001) to allow us to calculate realistic wavelength-dependent lightcurves and low-resolution spectra for direct comparison to data. This work is supported by National Science Foundation Grant No. 0307638 and National Aeronautics and Space Administration Grant No. NNG 04GQ35G.

Estimation of bioavailability of metals from drilling mud barite.

PubMed

Neff, Jerry M

2008-04-01

Drilling mud and associated drill cuttings are the largest volume wastes associated with drilling of oil and gas wells and often are discharged to the ocean from offshore drilling platforms. Barite (BaSO4) often is added as a weighting agent to drilling muds to counteract pressure in the geologic formations being drilled, preventing a blowout. Some commercial drilling mud barites contain elevated (compared to marine sediments) concentrations of several metals. The metals, if bioavailable, may harm the local marine ecosystem. The bioavailable fraction of metals is the fraction that dissolves from the nearly insoluble, solid barite into seawater or sediment porewater. Barite-seawater and barite-porewater distribution coefficients (Kd) were calculated for determining the predicted environmental concentration (PEC; the bioavailable fraction) of metals from drilling mud barite in the water column and sediments, respectively. Values for Kdbarite-seawater and Kdbarite-porewater were calculated for barium, cadmium, chromium, copper, mercury, lead, and zinc in different grades of barite. Log Kdbarite-seawater values were higher (solubility was lower) for metals in the produced water plume than log Kdbarite-porewater values for metals in sediments. The most soluble metals were cadmium and zinc and the least soluble were mercury and copper. Log Kd values can be used with data on concentrations of metals in barite and of barite in the drilling mud-cuttings plume and in bottom sediments to calculate PECseawater and PECsediment.

Real-time forecasting of ICME shock arrivals at L1 during the "April Fool’s Day" epoch: 28 March  21 April 2001

NASA Astrophysics Data System (ADS)

Sun, W.; Dryer, M.; Fry, C. D.; Deehr, C. S.; Smith, Z.; Akasofu, S.-I.; Kartalev, M. D.; Grigorov, K. G.

2002-07-01

The Sun was extremely active during the "April Fool’s Day" epoch of 2001. We chose this period between a solar flare on 28 March 2001 to a final shock arrival at Earth on 21 April 2001. The activity consisted of two presumed helmet-streamer blowouts, seven M-class flares, and nine X-class flares, the last of which was behind the west limb. We have been experimenting since February 1997 with real-time, end-to-end forecasting of interplanetary coronal mass ejection (ICME) shock arrival times. Since August 1998, these forecasts have been distributed in real-time by e-mail to a list of interested scientists and operational USAF and NOAA forecasters. They are made using three different solar wind models. We describe here the solar events observed during the April Fool’s 2001 epoch, along with the predicted and actual shock arrival times, and the ex post facto correction to the real-time coronal shock speed observations. It appears that the initial estimates of coronal shock speeds from Type II radio burst observations and coronal mass ejections were too high by as much as 30%. We conclude that a 3-dimensional coronal density model should be developed for application to observations of solar flares and their Type II radio burst observations.

Generation and measurement of velocity bunched ultrashort bunch of pC charge

DOE PAGES

Lu, X.  H.; Tang, C.  X.; Li, R.  K.; ...

2015-03-01

In this paper, we discuss the velocity compression in a short rf linac of an electron bunch from a rf photoinjector operated in the blowout regime. Particle tracking simulations shows that with a beam charge of 2 pC an ultrashort bunch duration of 16 fs can be obtained at a tight longitudinal focus downstream of the linac. A simplified coherent transition radiation (CTR) spectrum method is developed to enable the measurement of ultrashort (sub-50 fs) bunches at low bunch energy (5 MeV) and low bunch charges (<10 pC). In this method, the ratio of the radiation energy selected by twomore » narrow bandwidth filters is used to estimate the bunch length. The contribution to the coherent form factor of the large transverse size of the bunch suppresses the radiation signal significantly and is included in the analysis. The experiment was performed at the UCLA Pegasus photoinjector laboratory. The measurement results show bunches of sub-40 fs with 2 pC of charge well consistent with the simulation using actual experimental conditions. These results open the way to the generation of ultrashort bunches with time-duration below 10 fs once some of the limitations of the setup (rf phase jitter, amplitude instability and low field in the gun limited by breakdown) are corrected.« less

Screening for Dissolved Methane in Groundwater Across Texas Shale Plays

NASA Astrophysics Data System (ADS)

Nicot, J. P.; Mickler, P. J.; Hildenbrand, Z.; Larson, T.; Darvari, R.; Uhlman, K.; Smyth, R. C.; Scanlon, B. R.

2014-12-01

There is considerable interest in methane concentrations in groundwater, particularly as they relate to hydraulic fracturing in shale plays. Recent studies of aquifers in the footprint of several gas plays across the US have shown that (1) dissolved thermogenic methane may or may not be present in the shallow groundwater and (2) shallow thermogenic methane may be naturally occurring and emplaced through mostly vertical migration over geologic time and not necessarily a consequence of recent unconventional gas production. We are currently conducting a large sampling campaign across the state of Texas to characterize shallow methane in fresh-water aquifers overlying shale plays and other tight formations. We collected a total of ~800 water samples, ~500 in the Barnett, ~150 in the Eagle Ford, ~80 in the Haynesville shale plays as well as ~50 in the Delaware Basin of West Texas. Preliminary analytical results suggest that dissolved methane is not widespread in shallow groundwater and that, when present at concentrations exceeding 10 mg/L, it is often of thermogenic origin according to the isotopic signature and to the presence of other light hydrocarbons. The Barnett Shale contains a large methane hotspot (~ 2 miles wide) along the Hood-Parker county line which is likely of natural origin whereas the Eagle Ford and Haynesville shales, neglecting microbial methane, show more distributed methane occurrences. Samples from the Delaware Basin show no methane except close to blowouts.

Simulation of Deepwater Horizon oil plume reveals substrate specialization within a complex community of hydrocarbon degraders.

PubMed

Hu, Ping; Dubinsky, Eric A; Probst, Alexander J; Wang, Jian; Sieber, Christian M K; Tom, Lauren M; Gardinali, Piero R; Banfield, Jillian F; Atlas, Ronald M; Andersen, Gary L

2017-07-11

The Deepwater Horizon (DWH) accident released an estimated 4.1 million barrels of oil and 10 10 mol of natural gas into the Gulf of Mexico, forming deep-sea plumes of dispersed oil droplets and dissolved gases that were largely degraded by bacteria. During the course of this 3-mo disaster a series of different bacterial taxa were enriched in succession within deep plumes, but the metabolic capabilities of the different populations that controlled degradation rates of crude oil components are poorly understood. We experimentally reproduced dispersed plumes of fine oil droplets in Gulf of Mexico seawater and successfully replicated the enrichment and succession of the principal oil-degrading bacteria observed during the DWH event. We recovered near-complete genomes, whose phylogeny matched those of the principal biodegrading taxa observed in the field, including the DWH Oceanospirillales (now identified as a Bermanella species), multiple species of Colwellia , Cycloclasticus , and other members of Gammaproteobacteria, Flavobacteria, and Rhodobacteria. Metabolic pathway analysis, combined with hydrocarbon compositional analysis and species abundance data, revealed substrate specialization that explained the successional pattern of oil-degrading bacteria. The fastest-growing bacteria used short-chain alkanes. The analyses also uncovered potential cooperative and competitive relationships, even among close relatives. We conclude that patterns of microbial succession following deep ocean hydrocarbon blowouts are predictable and primarily driven by the availability of liquid petroleum hydrocarbons rather than natural gases.

Applications of the Amplatzer Vascular Plug to various vascular lesions

PubMed Central

Güneyli, Serkan; Çınar, Celal; Bozkaya, Halil; Parıldar, Mustafa; Oran, İsmail

2014-01-01

The Amplatzer® Vascular Plug (AVP) can be used to embolize medium-to-large high-flow vessels in various locations. Between 2009 and 2012, 41 AVPs (device size, 6–22 mm in diameter) were used to achieve occlusion in 31 patients (24 males, seven females) aged 9–92 years (mean age, 54.5 years). The locations and indications for embolotherapy were as follows: internal iliac artery embolization before stent-graft repair for aorto-iliac (n=6) and common iliac artery (n=3) aneurysms, subclavian artery embolization before stent-graft repair for thoracic aorta (n=3) and arcus aorta (n=1) aneurysms, brachiocephalic trunk embolization before stent-graft repair for a thoracic aorta aneurysm (n=1), embolization of aneurysms and pseudoaneurysms (n=5), embolization for carotid blow-out syndrome (n=3), closure of arteriovenous fistula (n=8), and closure of a portosystemic fistula (n=1). Of the 41 AVPs, 30 were AVP 2 and 11 were AVP 4. The mean follow-up duration was 4.7 months (range, 1–24 months). During follow-up, there was one migration, one insufficient embolization, and one recanalization. The remaining vascular lesions were successfully excluded from the circulation. The AVP, which can be used in a wide spectrum of pathologies, is easy to use and causes few complications. This essay presents our experience with the AVP. PMID:24047719

Simulation of Deepwater Horizon oil plume reveals substrate specialization within a complex community of hydrocarbon degraders

PubMed Central

Hu, Ping; Probst, Alexander J.; Wang, Jian; Sieber, Christian M. K.; Tom, Lauren M.; Gardinali, Piero R.; Banfield, Jillian F.; Atlas, Ronald M.

2017-01-01

The Deepwater Horizon (DWH) accident released an estimated 4.1 million barrels of oil and 1010 mol of natural gas into the Gulf of Mexico, forming deep-sea plumes of dispersed oil droplets and dissolved gases that were largely degraded by bacteria. During the course of this 3-mo disaster a series of different bacterial taxa were enriched in succession within deep plumes, but the metabolic capabilities of the different populations that controlled degradation rates of crude oil components are poorly understood. We experimentally reproduced dispersed plumes of fine oil droplets in Gulf of Mexico seawater and successfully replicated the enrichment and succession of the principal oil-degrading bacteria observed during the DWH event. We recovered near-complete genomes, whose phylogeny matched those of the principal biodegrading taxa observed in the field, including the DWH Oceanospirillales (now identified as a Bermanella species), multiple species of Colwellia, Cycloclasticus, and other members of Gammaproteobacteria, Flavobacteria, and Rhodobacteria. Metabolic pathway analysis, combined with hydrocarbon compositional analysis and species abundance data, revealed substrate specialization that explained the successional pattern of oil-degrading bacteria. The fastest-growing bacteria used short-chain alkanes. The analyses also uncovered potential cooperative and competitive relationships, even among close relatives. We conclude that patterns of microbial succession following deep ocean hydrocarbon blowouts are predictable and primarily driven by the availability of liquid petroleum hydrocarbons rather than natural gases. PMID:28652349

Large Scale Behavior and Droplet Size Distributions in Crude Oil Jets and Plumes

NASA Astrophysics Data System (ADS)

Katz, Joseph; Murphy, David; Morra, David

2013-11-01

The 2010 Deepwater Horizon blowout introduced several million barrels of crude oil into the Gulf of Mexico. Injected initially as a turbulent jet containing crude oil and gas, the spill caused formation of a subsurface plume stretching for tens of miles. The behavior of such buoyant multiphase plumes depends on several factors, such as the oil droplet and bubble size distributions, current speed, and ambient stratification. While large droplets quickly rise to the surface, fine ones together with entrained seawater form intrusion layers. Many elements of the physics of droplet formation by an immiscible turbulent jet and their resulting size distribution have not been elucidated, but are known to be significantly influenced by the addition of dispersants, which vary the Weber Number by orders of magnitude. We present experimental high speed visualizations of turbulent jets of sweet petroleum crude oil (MC 252) premixed with Corexit 9500A dispersant at various dispersant to oil ratios. Observations were conducted in a 0.9 m × 0.9 m × 2.5 m towing tank, where large-scale behavior of the jet, both stationary and towed at various speeds to simulate cross-flow, have been recorded at high speed. Preliminary data on oil droplet size and spatial distributions were also measured using a videoscope and pulsed light sheet. Sponsored by Gulf of Mexico Research Initiative (GoMRI).

Little gem

NASA Image and Video Library

2015-08-03

This colourful bubble is a planetary nebula called NGC 6818, also known as the Little Gem Nebula. It is located in the constellation of Sagittarius (The Archer), roughly 6000 light-years away from us. The rich glow of the cloud is just over half a light-year across — humongous compared to its tiny central star — but still a little gem on a cosmic scale. When stars like the Sun enter retirement, they shed their outer layers into space to create glowing clouds of gas called planetary nebulae. This ejection of mass is uneven, and planetary nebulae can have very complex shapes. NGC 6818 shows knotty filament-like structures and distinct layers of material, with a bright and enclosed central bubble surrounded by a larger, more diffuse cloud. Scientists believe that the stellar wind from the central star propels the outflowing material, sculpting the elongated shape of NGC 6818. As this fast wind smashes through the slower-moving cloud it creates particularly bright blowouts at the bubble’s outer layers. Hubble previously imaged this nebula back in 1997 with its Wide Field Planetary Camera 2, using a mix of filters that highlighted emission from ionised oxygen and hydrogen (opo9811h). This image, while from the same camera, uses different filters to reveal a different view of the nebula. A version of the image was submitted to the Hubble’s Hidden Treasures image processing competition by contestant Judy Schmidt.

The Canadian experience in frontier environmental protection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jones, G.H.

1991-03-01

Early Canadian frontier exploration (from 1955 onshore and from 1966 for offshore drilling) caused insignificant public concern. The 1967-1968 Torrey Canyon Tanker and Santa Barbara disasters roused public opinion and governments. In Canada, 1969-1970 Arctic gas blowouts, a tanker disaster, and damage to the 'Manhattan' exacerbated concerns and resulted in new environmental regulatory constraints. From 1970, the Arctic Petroleum Operations Association learned to operate safely with environmental responsibility. It studied physical environment for design criteria, and the biological and human environment to ameliorate impact. APOA's research projects covered sea-ice, permafrost, sea-bottom, oil-spills, bird and mammal migration, fish habitat, food chains,more » oceanography, meteorology, hunters'/trappers' harvests, etc. In 1971 Eastcoast Petroleum Operators' Association and Alaska Oil and Gas Association followed APOA's cooperative research model. EPOA stressed icebergs and fisheries. Certain research was handled by the Canadian Offshore Oil Spill Research Association. By the mid-1980s these associations had undertaken $70,000,000 of environmental oriented research, with equivalent additional work by member companies on specific needs and similar sums by Federal agencies often working with industry on complementary research. The frontier associations then merged with the Canadian Petroleum Association, already active environmentally in western Canada. Working with government and informing environmental interest groups, the public, natives, and local groups, most Canadian frontier petroleum operations proceeded with minimal delay and environmental disturbance.« less

Seawater capacitance – a promising proxy for mapping and characterizing drifting hydrocarbon plumes in the deep ocean

USGS Publications Warehouse

Wynn, Jeff; Fleming, John A.

2012-01-01

Hydrocarbons released into the deep ocean are an inevitable consequence of natural seep, seafloor drilling, and leaking wellhead-to-collection-point pipelines. The Macondo 252 (Deepwater Horizon) well blowout of 2010 was even larger than the Ixtoc event in the Gulf of Campeche in 1979. History suggests it will not be the last accidental release, as deepwater drilling expands to meet an ever-growing demand. For those who must respond to this kind of disaster, the first line of action should be to know what is going on. This includes knowing where an oil plume is at any given time, where and how fast it is moving, and how it is evolving or degrading. We have experimented in the laboratory with induced polarization as a method to track hydrocarbons in the seawater column and find that finely dispersed oil in seawater gives rise to a large distributed capacitance. From previous sea trials, we infer this could potentially be used to both map and characterize oil plumes, down to a ratio of less than 0.001 oil-to-seawater, drifting and evolving in the deep ocean. A side benefit demonstrated in some earlier sea trials is that this same approach in modified form can also map certain heavy placer minerals, as well as communication cables, pipelines, and wrecks buried beneath the seafloor.

Oil spill modeling in the southeastern Mediterranean Sea in support of accelerated offshore oil and gas exploration

NASA Astrophysics Data System (ADS)

Brenner, Steve

2015-12-01

Since the discovery of major reserves in the Israeli exclusive economic zone (EEZ) 6 years ago, exploration and drilling for natural gas and oil have proceeded at an accelerated pace. As part of the licensing procedure for drilling, an environmental impact assessment and an emergency response plan must be presented to the authorities, which include several prespecified oil spill simulations. In this study, the MEDSLIK oil spill model has been applied for this purpose. The model accounts for time-dependent advection, dispersion, and physiochemical weathering of the surface slick. It is driven by currents produced by high-resolution dynamic downscaling of ocean reanalysis data and winds extracted from global atmospheric analyses. Worst case scenarios based on 30-day well blowouts under four sets of environmental conditions were simulated for wells located at 140, 70, and 20 km off the coast of central Israel. For the well furthest from the coast, the amount of oil remaining in the surface slick always exceeds the amount deposited on the coast. For the mid-distance well, the cases were evenly split. For the well closest to the coast, coastal deposition always exceeds the oil remaining in the slick. Additional simulations with the wind switched off helped highlight the importance of the wind in evaporation of the oil and in transporting the slick toward the southeastern coast.

Experimental and Computational Study of Trapped Vortex Combustor Sector Rig with Tri-pass Diffuser

NASA Technical Reports Server (NTRS)

Hendricks, Robert C.; Shouse, D. T.; Roquemore, W. M.; Burrus, D. L.; Duncan, B. S.; Ryder, R. C.; Brankovic, A.; Liu, N.-S.; Gallagher, J. R.; Hendricks, J. A.

2001-01-01

The Trapped Vortex Combustor (TVC) potentially offers numerous operational advantages over current production gas turbine engine combustors. These include lower weight, lower pollutant emissions, effective flame stabilization, high combustion efficiency, excellent high altitude relight capability, and operation in the lean burn or RQL (Rich burn/Quick mix/Lean burn) modes of combustion. The present work describes the operational principles of the TVC, and provides detailed performance data on a configuration featuring a tri-pass diffusion system. Performance data include EINOx (NO(sub x) emission index) results for various fuel-air ratios and combustor residence times, combustion efficiency as a function of combustor residence time, and combustor lean blow-out (LBO) performance. Computational fluid dynamics (CFD) simulations using liquid spray droplet evaporation and combustion modeling are performed and related to flow structures observed in photographs of the combustor. The CFD results are used to understand the aerodynamics and combustion features under different fueling conditions. Performance data acquired to date are favorable in comparison to conventional gas turbine combustors. Further testing over a wider range of fuel-air ratios, fuel flow splits, and pressure ratios is in progress to explore the TVC performance. In addition, alternate configurations for the upstream pressure feed, including bi-pass diffusion schemes, as well as variations on the fuel injection patterns, are currently in test and evaluation phases.

Compact tunable Compton x-ray source from laser-plasma accelerator and plasma mirror

NASA Astrophysics Data System (ADS)

Tsai, Hai-En; Wang, Xiaoming; Shaw, Joseph M.; Li, Zhengyan; Arefiev, Alexey V.; Zhang, Xi; Zgadzaj, Rafal; Henderson, Watson; Khudik, V.; Shvets, G.; Downer, M. C.

2015-02-01

We present an in-depth experimental-computational study of the parameters necessary to optimize a tunable, quasi-monoenergetic, efficient, low-background Compton backscattering (CBS) x-ray source that is based on the self-aligned combination of a laser-plasma accelerator (LPA) and a plasma mirror (PM). The main findings are (1) an LPA driven in the blowout regime by 30 TW, 30 fs laser pulses produce not only a high-quality, tunable, quasi-monoenergetic electron beam, but also a high-quality, relativistically intense (a0 ˜ 1) spent drive pulse that remains stable in profile and intensity over the LPA tuning range. (2) A thin plastic film near the gas jet exit retro-reflects the spent drive pulse efficiently into oncoming electrons to produce CBS x-rays without detectable bremsstrahlung background. Meanwhile, anomalous far-field divergence of the retro-reflected light demonstrates relativistic "denting" of the PM. Exploiting these optimized LPA and PM conditions, we demonstrate quasi-monoenergetic (50% FWHM energy spread), tunable (75-200 KeV) CBS x-rays, characteristics previously achieved only on more powerful laser systems by CBS of a split-off, counter-propagating pulse. Moreover, laser-to-x-ray photon conversion efficiency (˜6 × 10-12) exceeds that of any previous LPA-based quasi-monoenergetic Compton source. Particle-in-cell simulations agree well with the measurements.

Abnormal pressure study in the Malay and Penyu Basins: A regional understanding

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kader, M.S.; Leslie, W.

1994-07-01

A majority of wells drilled in the Malay and Penyu basins were terminated due to abnormal pressure. Blowouts and the subsequent loss of technical data have always been a concern during drilling operations. This study employs data from 94 exploratory wells spread throughout the Malay and Penyu basins. The postdrill abnormal pressure predictive method used is pressure vs. depth plots of data obtained from Repeat Formation tester (RFT) readings. The study results indicate that abnormal pressure occurs in a progressively older stratigraphic unit toward the basin margins. The margins of the Malay and the entire Penyu basins tend to bemore » normally pressured. The onset of abnormal pressure appears to be abrupt in the northern portion and more gradual in the southern part of the Malay Basin. Abnormal pressure in the Malay Basin is found to be neither depth dependent nor age related. Many factors can cause the abnormal formation pressures. In some areas, a combination of factors prevails. Rapid deposition of the middle to late Miocene siliciclastic sediments appears to be a dominant cause particularly in the center of the Malay Basin. A low sand:shale ratio coupled with a high geothermal gradient is also found to be a local cause near the axis of the basin. This phenomenon is crucial to the understanding of hydrocarbon migration and will enable the planning of safe and efficient drilling campaigns.« less

Subsea release of oil from a riser: an ecological risk assessment.

PubMed

Nazir, Muddassir; Khan, Faisal; Amyotte, Paul; Sadiq, Rehan

2008-10-01

This study illustrates a newly developed methodology, as a part of the U.S. EPA ecological risk assessment (ERA) framework, to predict exposure concentrations in a marine environment due to underwater release of oil and gas. It combines the hydrodynamics of underwater blowout, weathering algorithms, and multimedia fate and transport to measure the exposure concentration. Naphthalene and methane are used as surrogate compounds for oil and gas, respectively. Uncertainties are accounted for in multimedia input parameters in the analysis. The 95th percentile of the exposure concentration (EC(95%)) is taken as the representative exposure concentration for the risk estimation. A bootstrapping method is utilized to characterize EC(95%) and associated uncertainty. The toxicity data of 19 species available in the literature are used to calculate the 5th percentile of the predicted no observed effect concentration (PNEC(5%)) by employing the bootstrapping method. The risk is characterized by transforming the risk quotient (RQ), which is the ratio of EC(95%) to PNEC(5%), into a cumulative risk distribution. This article describes a probabilistic basis for the ERA, which is essential from risk management and decision-making viewpoints. Two case studies of underwater oil and gas mixture release, and oil release with no gaseous mixture are used to show the systematic implementation of the methodology, elements of ERA, and the probabilistic method in assessing and characterizing the risk.

[Bone cement implant as an alternative for orbital floor reconstruction: A case report].

PubMed

Vargas-Solalinde, Enrique; Huichapa-Padilla, Marisol E; Garza-Cantú, Daniel; Reyna-Martínez, Víctor H; Alatorre-Ricardo, Julio; González-Treviño, Juan Luis

2017-12-01

The management of orbitary fractures is one of the most challenging in facial trauma; the variety of reconstruction materials for its treatment is broad and is constantly improving, but despite this there is no consensus for its use or literature that sustains it. To present the use and design of a preformed bone implant as an alternative for the reconstruction of orbital floor fractures in the pediatric age group. A 7-year old male who suffered a right hemifacial contusion trauma with clinical and tomographic diagnosis of right pure blowout type orbital floor fracture with inferior rectus muscle entrapment and right post-traumatic palpebral ptosis. Successful surgical reconstruction was performed 7 days later with a pre-constructed bone cement implant. Eight weeks after surgery the patient presented with mild residual palpebral ptosis, no ocular movement limitations and no diplopia. The use of a bone cement implant can be considered appropriate for the reconstruction of these fractures, as another alternative to be used by the ophthalmologist among the variety of all the other materials used for this purpose. We consider that our optimism based on the results obtained in this case obligates us to increase the number of patients treated in order to gather more evidence and do larger follow up. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

Risk Management at NASA and Its Applicability to the Oil and Gas Industry

NASA Technical Reports Server (NTRS)

Kaplan, David

2018-01-01

NASA has a world-class capability for quantitatively assessing the risk of highly-complex, isolated engineering structures operated in extremely hostile environments. In particular, the International Space Station (ISS) represents a reasonable risk analog for High Pressure, High Temperature drilling and production operations on deepwater rigs. Through a long-term U.S. Government Interagency Agreement, BSEE has partnered with NASA to modify NASA's Probabilistic Risk Assessment (PRA) capabilities for application to deepwater drilling and production operations. The immediate focus of the activity will be to modify NASA PRA Procedure Guides and Methodology Documents to make them applicable to the Oil &Gas Industry. The next step will be for NASA to produce a PRA for a critical drilling system component, such as a Blowout Preventer (BOP). Subsequent activities will be for NASA and industry partners to jointly develop increasingly complex PRA's that analyze other critical drilling and production system components, including both hardware and human reliability. In the presentation, NASA will provide the objectives, schedule, and current status of its PRA activities for BSEE. Additionally, NASA has a Space Act Agreement with Anadarko Petroleum Corporation to develop a PRA for a generic 20K BOP. NASA will summarize some of the preliminary insights gained to date from that 20K BOP PRA as an example of the distinction between quantitative versus qualitative risk assessment.

Microbial transformation of the Deepwater Horizon oil spill—past, present, and future perspectives

PubMed Central

Kimes, Nikole E.; Callaghan, Amy V.; Suflita, Joseph M.; Morris, Pamela J.

2014-01-01

The Deepwater Horizon blowout, which occurred on April 20, 2010, resulted in an unprecedented oil spill. Despite a complex effort to cap the well, oil and gas spewed from the site until July 15, 2010. Although a large proportion of the hydrocarbons was depleted via natural processes and human intervention, a substantial portion of the oil remained unaccounted for and impacted multiple ecosystems throughout the Gulf of Mexico. The depth, duration and magnitude of this spill were unique, raising many questions and concerns regarding the fate of the hydrocarbons released. One major question was whether or not microbial communities would be capable of metabolizing the hydrocarbons, and if so, by what mechanisms and to what extent? In this review, we summarize the microbial response to the oil spill as described by studies performed during the past four years, providing an overview of the different responses associated with the water column, surface waters, deep-sea sediments, and coastal sands/sediments. Collectively, these studies provide evidence that the microbial response to the Deepwater Horizon oil spill was rapid and robust, displaying common attenuation mechanisms optimized for low molecular weight aliphatic and aromatic hydrocarbons. In contrast, the lack of evidence for the attenuation of more recalcitrant hydrocarbon components suggests that future work should focus on both the environmental impact and metabolic fate of recalcitrant compounds, such as oxygenated oil components. PMID:25477866

Simulating Gas-Liquid-Water Partitioning and Fluid Properties of Petroleum under Pressure: Implications for Deep-Sea Blowouts.

PubMed

Gros, Jonas; Reddy, Christopher M; Nelson, Robert K; Socolofsky, Scott A; Arey, J Samuel

2016-07-19

With the expansion of offshore petroleum extraction, validated models are needed to simulate the behaviors of petroleum compounds released in deep (>100 m) waters. We present a thermodynamic model of the densities, viscosities, and gas-liquid-water partitioning of petroleum mixtures with varying pressure, temperature, and composition based on the Peng-Robinson equation-of-state and the modified Henry's law (Krychevsky-Kasarnovsky equation). The model is applied to Macondo reservoir fluid released during the Deepwater Horizon disaster, represented with 279-280 pseudocomponents, including 131-132 individual compounds. We define >n-C8 pseudocomponents based on comprehensive two-dimensional gas chromatography (GC × GC) measurements, which enable the modeling of aqueous partitioning for n-C8 to n-C26 fractions not quantified individually. Thermodynamic model predictions are tested against available laboratory data on petroleum liquid densities, gas/liquid volume fractions, and liquid viscosities. We find that the emitted petroleum mixture was ∼29-44% gas and ∼56-71% liquid, after cooling to local conditions near the broken Macondo riser stub (∼153 atm and 4.3 °C). High pressure conditions dramatically favor the aqueous dissolution of C1-C4 hydrocarbons and also influence the buoyancies of bubbles and droplets. Additionally, the simulated densities of emitted petroleum fluids affect previous estimates of the volumetric flow rate of dead oil from the emission source.

Update on orbital reconstruction.

PubMed

Chen, Chien-Tzung; Chen, Yu-Ray

2010-08-01

Orbital trauma is common and frequently complicated by ocular injuries. The recent literature on orbital fracture is analyzed with emphasis on epidemiological data assessment, surgical timing, method of approach and reconstruction materials. Computed tomographic (CT) scan has become a routine evaluation tool for orbital trauma, and mobile CT can be applied intraoperatively if necessary. Concomitant serious ocular injury should be carefully evaluated preoperatively. Patients presenting with nonresolving oculocardiac reflex, 'white-eyed' blowout fracture, or diplopia with a positive forced duction test and CT evidence of orbital tissue entrapment require early surgical repair. Otherwise, enophthalmos can be corrected by late surgery with a similar outcome to early surgery. The use of an endoscope-assisted approach for orbital reconstruction continues to grow, offering an alternative method. Advances in alloplastic materials have improved surgical outcome and shortened operating time. In this review of modern orbital reconstruction, several controversial issues such as surgical indication, surgical timing, method of approach and choice of reconstruction material are discussed. Preoperative fine-cut CT image and thorough ophthalmologic examination are key elements to determine surgical indications. The choice of surgical approach and reconstruction materials much depends on the surgeon's experience and the reconstruction area. Prefabricated alloplastic implants together with image software and stereolithographic models are significant advances that help to more accurately reconstruct the traumatized orbit. The recent evolution of orbit reconstruction improves functional and aesthetic results and minimizes surgical complications.

A DIRECT MEASUREMENT OF THE BARYONIC MASS FUNCTION OF GALAXIES AND IMPLICATIONS FOR THE GALACTIC BARYON FRACTION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Papastergis, Emmanouil; Huang, Shan; Giovanelli, Riccardo

We use both an H I-selected and an optically selected galaxy sample to directly measure the abundance of galaxies as a function of their 'baryonic' mass (stars + atomic gas). Stellar masses are calculated based on optical data from the Sloan Digital Sky Survey and atomic gas masses are calculated using atomic hydrogen (H I) emission line data from the Arecibo Legacy Fast ALFA survey. By using the technique of abundance matching, we combine the measured baryonic function of galaxies with the dark matter halo mass function in a {Lambda}CDM universe, in order to determine the galactic baryon fraction asmore » a function of host halo mass. We find that the baryon fraction of low-mass halos is much smaller than the cosmic value, even when atomic gas is taken into account. We find that the galactic baryon deficit increases monotonically with decreasing halo mass, in contrast with previous studies which suggested an approximately constant baryon fraction at the low-mass end. We argue that the observed baryon fractions of low-mass halos cannot be explained by reionization heating alone, and that additional feedback mechanisms (e.g., supernova blowout) must be invoked. However, the outflow rates needed to reproduce our result are not easily accommodated in the standard picture of galaxy formation in a {Lambda}CDM universe.« less

Flame Interactions and Thermoacoustics in Multiple-Nozzle Combustors

NASA Astrophysics Data System (ADS)

Dolan, Brian

The first major chapter of original research (Chapter 3) examines thermoacoustic oscillations in a low-emission staged multiple-nozzle lean direct injection (MLDI) combustor. This experimental program investigated a relatively practical combustor sector that was designed and built as part of a commercial development program. The research questions are both practical, such as under what conditions the combustor can be safely operated, and fundamental, including what is most significant to driving the combustion oscillations in this system. A comprehensive survey of operating conditions finds that the low-emission (and low-stability) intermediate and outer stages are necessary to drive significant thermoacoustics. Phase-averaged and time-resolved OH* imaging show that dramatic periodic strengthening and weakening of the reaction zone downstream of the low-emission combustion stages. An acoustic modal analysis shows the pressure wave shapes and identifies the dominant thermoacoustic behavior as the first longitudinal mode for this combustor geometry. Finally, a discussion of the likely significant coupling mechanisms is given. Periodic reaction zone behavior in the low-emission fuel stages is the primary contributor to unsteady heat release. Differences between the fuel stages in the air swirler design, the fuel number of the injectors, the lean blowout point, and the nominal operating conditions all likely contribute to the limit cycle behavior of the low-emission stages. Chapter 4 investigates the effects of interaction between two adjacent swirl-stabilized nozzles using experimental and numerical tools. These studies are more fundamental; while the nozzle hardware is the same as the lean direct injection nozzles used in the MLDI combustion concept, the findings are generally applicable to other swirl-stabilized combustion systems as well. Much of the work utilizes a new experiment where the distance between nozzles was varied to change the level of interaction between the two nozzles. A decrease in inter-nozzle spacing resulted in a penalty to the lean blowout point and NO X emissions. Particle image velocimetry shows that the nozzle spacing also has an important effect on the flowfield of the nozzles including the shape of the recirculation region and the quantitative flow velocities. In particular, interaction in the tangential velocity between the two nozzles has large effects on the swirl number and the recirculation zone. Numerical simulations of the isothermal airflows of two pilot nozzles are validated using experimental measurements and used to provide flowfield information outside of the measurement domain. At wider inter-nozzle spacings under certain reacting conditions, an alternating flow pattern develops in the combustion chamber. The shear layers of one nozzle extent into the combustion chamber whereas the inlet reactants from the other nozzle attach near the dome wall to create a very wide recirculation region. Combustion properties, including the fuel type, are shown experimentally to affect whether or not a system will develop an alternating pattern. Simplified computational models of two interacting swirling flows are used to parametrically study the effects of nozzle exit geometry and swirl number on an alternating pattern. Both parameters are shown to be potential drivers of an alternating pattern under some conditions. A hypothesis that proposes a physical mechanism explaining the alternating flow pattern, consistent with the work in this proposal and the research of other groups, is presented. When the nozzle design, flow, or combustion characteristics cause the shear layers of the adjacent nozzles to become sufficiently opposite in direction, the two flows can no longer mix. Instead, one shear layer goes underneath the other which results in the differing flow features of the adjacent nozzles.

Staying in the zone: offshore drillers' situation awareness.

PubMed

Roberts, Ruby; Flin, Rhona; Cleland, Jennifer

2015-06-01

The aim of this study was to identify the cognitive components required for offshore drillers to develop and maintain situation awareness (SA) while controlling subsea hydrocarbon wells. SA issues are often identified as contributing factors to drilling incidents, most recently in the Deepwater Horizon blowout. Yet, there is a limited body of research investigating SA in the offshore drilling environment. In the first study, critical incident interviews were conducted with 18 experienced drilling personnel. Transcripts were subjected to theory-driven thematic analysis, producing a preliminary cognitive framework of how drillers develop and maintain SA during well control. In the second study, 24 hr of observations (in vivo and video) of drillers managing a high fidelity well-control simulator were analyzed to further develop the framework. The cognitive components that enable drillers to build up an understanding of what is happening in the wellbore and surrounding environment, to predict how this understanding may develop, were identified. These components included cue recognition, interpretation of information in conjunction with the current mental model, and projection through mental simulation. Factors such as distracters, expectations, and information sharing between crew members can both positively and negatively influence the drillers' SA. The findings give a preliminary understanding into the components of drillers' SA, highlighting the importance of SA for safe and effective performance and indicating that Endsley's model of SA can be applied to drilling. The results have consequences for training, task management, and work design recommendations. © 2014, Human Factors and Ergonomics Society.

Persistent impacts to the deep soft-bottom benthos one year after the Deepwater Horizon event.

PubMed

Montagna, Paul A; Baguley, Jeffrey G; Cooksey, Cynthia; Hyland, Jeffrey L

2017-03-01

In fall 2010, several months after the Deepwater Horizon blowout was capped, zones of moderate and severe impacts to deep-sea, soft-bottom benthos were identified that together extended over an area of 172 km 2 . A subset of stations sampled in 2010 was resampled in May and June 2011, 10 to 11 months after the event, to determine whether the identified adverse effects were persisting. The design compared 20 stations from the combined moderate and severe impact zone to 12 stations in the reference zone that were sampled in both years. There were no statistically significant differences in contaminant concentrations between the impact and nonimpact zones from 2010 to 2011, which indicates contaminants persisted after 1 y. Whereas there were some signs of recovery in 2011 (particularly for the meiofauna abundance and diversity), there was evidence of persistent, statistically significant impacts to both macrofauna and meiofauna community structure. Macrofaunal taxa richness and diversity in 2011 were still 22.8% and 35.9% less, respectively, in the entire impact zone than in the surrounding nonimpact area, and meiofaunal richness was 28.5% less in the entire impact zone than in the surrounding area. The persistence of significant biodiversity losses and community structure change nearly 1 y after the wellhead was capped indicates that full recovery had yet to have occurred in 2011. Integr Environ Assess Manag 2017;13:342-351. © 2016 SETAC. © 2016 SETAC.

Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime

NASA Astrophysics Data System (ADS)

Lu, W.; Tzoufras, M.; Joshi, C.; Tsung, F. S.; Mori, W. B.; Vieira, J.; Fonseca, R. A.; Silva, L. O.

2007-06-01

The extraordinary ability of space-charge waves in plasmas to accelerate charged particles at gradients that are orders of magnitude greater than in current accelerators has been well documented. We develop a phenomenological framework for laser wakefield acceleration (LWFA) in the 3D nonlinear regime, in which the plasma electrons are expelled by the radiation pressure of a short pulse laser, leading to nearly complete blowout. Our theory provides a recipe for designing a LWFA for given laser and plasma parameters and estimates the number and the energy of the accelerated electrons whether self-injected or externally injected. These formulas apply for self-guided as well as externally guided pulses (e.g. by plasma channels). We demonstrate our results by presenting a sample particle-in-cell (PIC) simulation of a 30fs, 200 TW laser interacting with a 0.75 cm long plasma with density 1.5×1018cm-3 to produce an ultrashort (10 fs) monoenergetic bunch of self-injected electrons at 1.5 GeV with 0.3 nC of charge. For future higher-energy accelerator applications, we propose a parameter space, which is distinct from that described by Gordienko and Pukhov [Phys. Plasmas 12, 043109 (2005)PHPAEN1070-664X10.1063/1.1884126] in that it involves lower plasma densities and wider spot sizes while keeping the intensity relatively constant. We find that this helps increase the output electron beam energy while keeping the efficiency high.

Experimental study on immiscible jet breakup using refractive index matched oil-water pair

NASA Astrophysics Data System (ADS)

Xue, Xinzhi; Katz, Joseph

2016-11-01

A subsea oil well blowout creates an immiscible crude oil jet. This jet fragments shortly after injection, resulting in generation of a droplet cloud. Detailed understanding of the processes involved is crucial for modeling the fragmentation and for predicting the droplet size distribution. High density of opaque droplets near nozzle limits our ability to visualize and quantify the breakup process. To overcome this challenge, two immiscible fluids: silicone oil and sugar water with the same index of refraction (1.4015) are used as surrogates for crude oil and seawater, respectively. Their ratios of kinematic viscosity (5.64), density (0.83) and interfacial tension are closely matched with those of crude oil and seawater. Distribution of the oil phase is visualized by fluorescent tagging. Both phases are also seeded with particles for simultaneous PIV measurements. The measurements are performed within atomization range of Ohnesorge and Reynolds numbers. Index matching facilitates undistorted view of the phase distribution in illuminated section. Ongoing tests show that the jet surface initially rolls up into Kelvin-Helmholtz rings, followed by development of dispersed phase ligaments further downstream, which then break into droplets. Some of these droplets are re-entrained into the high momentum core, resulting in secondary breakup. As the oil layer and ligaments evolve, they often entrain water, resulting in generation of multiple secondary water droplets encapsulated within the oil droplets. This research is made possible by a Grant from Gulf of Mexico Research Initiative.