40 CFR 60.273 - Emission monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other condition that may....273 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... installs and continuously operates a bag leak detection system according to paragraph (e) of this section...

40 CFR 60.273a - Emission monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

... following: (1) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other....273a Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... by a certified visible emission observer and the owner installs and continuously operates a bag leak...

40 CFR 60.273a - Emission monitoring.

Code of Federal Regulations, 2012 CFR

2012-07-01

... following: (1) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other....273a Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... by a certified visible emission observer and the owner installs and continuously operates a bag leak...

40 CFR 65.118 - Alternative means of emission limitation: Enclosed-vented process units.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.118... control device. Process units that are enclosed in such a manner that all emissions from equipment leaks...

40 CFR 63.7920 - What emissions limitations and work practice standards must I meet for equipment leaks?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Equipment Leaks § 63.7920 What emissions limitations and work practice standards...

40 CFR 63.7920 - What emissions limitations and work practice standards must I meet for equipment leaks?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Equipment Leaks § 63.7920 What emissions limitations and work practice standards...

40 CFR 63.7920 - What emissions limitations and work practice standards must I meet for equipment leaks?

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Equipment Leaks § 63.7920 What emissions limitations and work practice standards...

40 CFR 63.7920 - What emissions limitations and work practice standards must I meet for equipment leaks?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Equipment Leaks § 63.7920 What emissions limitations and work practice standards...

40 CFR 63.7920 - What emissions limitations and work practice standards must I meet for equipment leaks?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation Equipment Leaks § 63.7920 What emissions limitations and work practice standards...

Transepithelial leak in Barrett's esophagus patients: The role of proton pump inhibitors

PubMed Central

Farrell, Christopher; Morgan, Melissa; Tully, Owen; Wolov, Kevin; Kearney, Keith; Ngo, Benjamin; Mercogliano, Giancarlo; Thornton, James J; Valenzano, Mary Carmen; Mullin, James M

2012-01-01

AIM: To determine if the observed paracellular sucrose leak in Barrett’s esophagus patients is due to their proton pump inhibitor (PPI) use. METHODS: The in vivo sucrose permeability test was administered to healthy controls, to Barrett’s patients and to non-Barrett’s patients on continuous PPI therapy. Degree of leak was tested for correlation with presence of Barrett’s, use of PPIs, and length of Barrett’s segment and duration of PPI use. RESULTS: Barrett’s patients manifested a near 3-fold greater, upper gastrointestinal sucrose leak than healthy controls. A decrease of sucrose leak was observed in Barrett’s patients who ceased PPI use for 7 d. Although initial introduction of PPI use (in a PPI-naïve population) results in dramatic increase in sucrose leak, long-term, continuous PPI use manifested a slow spontaneous decline in leak. The sucrose leak observed in Barrett’s patients showed no correlation to the amount of Barrett’s tissue present in the esophagus. CONCLUSION: Although future research is needed to determine the degree of paracellular leak in actual Barrett’s mucosa, the relatively high degree of leak observed with in vivo sucrose permeability measurement of Barrett’s patients reflects their PPI use and not their Barrett’s tissue per se. PMID:22719187

Microseismic response characteristics modeling and locating of underground water supply pipe leak

NASA Astrophysics Data System (ADS)

Wang, J.; Liu, J.

2015-12-01

In traditional methods of pipeline leak location, geophones must be located on the pipe wall. If the exact location of the pipeline is unknown, the leaks cannot be identified accurately. To solve this problem, taking into account the characteristics of the pipeline leak, we propose a continuous random seismic source model and construct geological models to investigate the proposed method for locating underground pipeline leaks. Based on two dimensional (2D) viscoacoustic equations and the staggered grid finite-difference (FD) algorithm, the microseismic wave field generated by a leaking pipe is modeled. Cross-correlation analysis and the simulated annealing (SA) algorithm were utilized to obtain the time difference and the leak location. We also analyze and discuss the effect of the number of recorded traces, the survey layout, and the offset and interval of the traces on the accuracy of the estimated location. The preliminary results of the simulation and data field experiment indicate that (1) a continuous random source can realistically represent the leak microseismic wave field in a simulation using 2D visco-acoustic equations and a staggered grid FD algorithm. (2) The cross-correlation method is effective for calculating the time difference of the direct wave relative to the reference trace. However, outside the refraction blind zone, the accuracy of the time difference is reduced by the effects of the refracted wave. (3) The acquisition method of time difference based on the microseismic theory and SA algorithm has a great potential for locating leaks from underground pipelines from an array located on the ground surface. Keywords: Viscoacoustic finite-difference simulation; continuous random source; simulated annealing algorithm; pipeline leak location

40 CFR 65.146 - Nonflare control devices used for equipment leaks only.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Closed Vent Systems, Control Devices, and Routing to a Fuel Gas System or a Process § 65.146 Nonflare control devices used for equipment leaks only...

40 CFR 60.5225 - What are the monitoring and calibration requirements for compliance with my operating limits?

Code of Federal Regulations, 2014 CFR

2014-07-01

... limited to the following: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... maintain your bag leak detection system in continuous operation according to your monitoring plan required...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2012 CFR

2012-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

40 CFR 60.5225 - What are the monitoring and calibration requirements for compliance with my operating limits?

Code of Federal Regulations, 2013 CFR

2013-07-01

... limited to the following: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... maintain your bag leak detection system in continuous operation according to your monitoring plan required...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2014 CFR

2014-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2013 CFR

2013-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

Continuous time-resolved regional methane leak detection with on-line background estimation using a novel combination of dual frequency comb laser spectroscopy and atmospheric inversions

NASA Astrophysics Data System (ADS)

Alden, C. B.; Coburn, S.; Wright, R.; Baumann, E.; Cossel, K.; Sweeney, C.; Ghosh, S.; Newbury, N.; Prasad, K.; Coddington, I.; Rieker, G. B.

2017-12-01

Advances in natural gas extraction technology have led to increased US production and transport activity, and as a consequence, an increased need for monitoring of methane leaks. Current leak detection methods provide time snapshots, and not continuous, time-varying estimates of emissions. Most approaches also require specific atmospheric conditions, operators, or the use of a tracer gas, requiring site access. Given known intermittency in fugitive methane emissions, continuous monitoring is a critical need for emissions mitigation. We present a novel leak detection method that employs dual frequency comb spectrometry to offer continuous, autonomous, leak detection and quantification over square-km scale areas. The spectrometer is situated in a field of natural gas pads, and a series of retroreflectors around the field direct light back to a detector. The laser light spans 1620-1680 nm with 0.002 nm line spacing, measuring thousands of individual absorption features from multiple species. The result is high-stability trace gas (here CH4, CO2, and H2O) measurements over long (1 km+) open paths through the atmosphere. Measurements are used in an atmospheric inversion to estimate the time variability of emissions at each location of interest. Importantly, the measurement framework and inversion solve explicitly for background concentrations, which vary rapidly in fields of active oil and gas production. We present the results of controlled-leak field tests in rural Colorado. We demonstrate the ability to locate and size a leak located 1 km away from the spectrometer and varying in strength from 1.5 to 7.7 g/min, resulting in mean atmospheric enhancements of 20 ppb. The inversion correctly identifies when the leak turned on and off over a 24-hour period, and determines the mean leak strength to within 10% of the true controlled rate. We further demonstrate the ability of the system to correctly locate and size the start and end of simultaneous 2.7 to 4.8 g/min leaks from 2 sources in a field of 5 potential leak locations. Finally, we present the results of leak-detection tests in active oil and gas fields in the Denver Julesburg Basin, where background methane is complex.

40 CFR 61.135 - Standard: Equipment leaks.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Section 61.135 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Benzene Emissions from Coke By-Product Recovery Plants § 61.135 Standard: Equipment leaks. (a) Each owner or...

40 CFR 63.7833 - How do I demonstrate continuous compliance with the emission limitations that apply to me?

Code of Federal Regulations, 2010 CFR

2010-07-01

... baghouse equipped with a bag leak detection system, operating and maintaining each bag leak detection... requirements. If you increase or decrease the sensitivity of the bag leak detection system beyond the limits... event of a bag leak detection system alarm or when the hourly average opacity exceeded 5 percent, the...

Method and apparatus for continuous fluid leak monitoring and detection in analytical instruments and instrument systems

DOEpatents

Weitz, Karl K [Pasco, WA; Moore, Ronald J [West Richland, WA

2010-07-13

A method and device are disclosed that provide for detection of fluid leaks in analytical instruments and instrument systems. The leak detection device includes a collection tube, a fluid absorbing material, and a circuit that electrically couples to an indicator device. When assembled, the leak detection device detects and monitors for fluid leaks, providing a preselected response in conjunction with the indicator device when contacted by a fluid.

Outcomes of asymptomatic anastomotic leaks found on routine postoperative water-soluble enema following anterior resection for cancer.

PubMed

Killeen, S; Souroullas, P; Ho Tin, H; Hunter, I A; O'Grady, H; Gunn, J; Hartley, J E

2013-11-01

The incidence and consequence of an anastomotic leak associated with low anterior resection for cancer mandates covering stoma in most cases. A water-soluble enema is often performed to assess anastomotic integrity prior to stoma reversal. The functional outcome following reversal in patients with occult radiologically detected leaks is poorly defined. The goal of the present study was to determine the functional outcome in patients with a radiologically detected anastomotic leak who subsequently underwent stoma reversal. This case control study used patients with and without radiologically detected occult anastomotic leak having undergone reversal of covering stomata. The study group was matched with controls for age, gender, procedure, tumor stage, and adjuvant/neoadjuvant therapy. Validated fecal incontinence quality of life (FIQL), Cleveland Clinic Fecal Incontinence Score (CCFIS), and the Memorial Sloan-Kettering Cancer Center (MSKCC) Bowel Function Index (BFI) were used. Patient satisfaction, medication use, and ancillary procedures prior to closure were also recorded. Thirteen patients with radiologically detected occult anastomotic leaks and 13 matched controls were identified from a prospectively maintained database. The FIQL, CCFIS, and MSKCC BFI scores were significantly reduced in those with occult leaks. The mean number of radiological and surgical interventions was significantly greater in the patients with occult leaks. Antidiarrheal and bulking agent use, as well as patient satisfaction, were the same for both groups. Only one patient in the occult leak group would not undergo stoma reversal again. Reversal of a defunctioning ileostomy in the presence of an occult radiological leak can be associated with poorer functional outcomes, but patient satisfaction is undiminished.

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

40 CFR 1065.644 - Vacuum-decay leak rate.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Vacuum-decay leak rate. 1065.644 Section 1065.644 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calculations and Data Requirements § 1065.644 Vacuum-decay leak rate...

Study of Residual Gas Analyser (RGA) Response towards Known Leaks

NASA Astrophysics Data System (ADS)

Pathan, Firozkhan S.; Khan, Ziauddin; Semwal, Pratibha; George, Siju; Raval, Dilip C.; Thankey, Prashant L.; Manthena, Himabindu; Yuvakiran, Paravastu; Dhanani, Kalpesh R.

2012-11-01

Helium leak testing is the most versatile form of weld qualification test for any vacuum application. Almost every ultra-high vacuum (UHV) system utilizes this technique for insuring leak tightness for the weld joints as well as demountable joints. During UHV system under operational condition with many other integrated components, in-situ developed leaks identification becomes one of the prime aspect for maintaining the health of such system and for continuing the experiments onwards. Since online utilization of leak detector (LD) has many practical limitations, residual gas analyser (RGA) can be used as a potential instrument for online leak detection. For this purpose, a co-relation for a given leak rate between Leak Detector and RGA is experimentally established. This paper describes the experimental aspect and the relationship between leak detector and RGA.

40 CFR 60.51c - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF... Incinerators for Which Construction is Commenced After June 20, 1996 § 60.51c Definitions. Bag leak detection... order to detect bag failures. A bag leak detection system includes, but is not limited to, an instrument...

40 CFR 60.51c - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF... Incinerators for Which Construction is Commenced After June 20, 1996 § 60.51c Definitions. Bag leak detection... order to detect bag failures. A bag leak detection system includes, but is not limited to, an instrument...

40 CFR 60.256 - Continuous monitoring requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

....256 Section 60.256 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... rates of 25 Mg (28 tons) per year or more, a bag leak detection system according to the requirements in... performance test on an operating day average basis. (c) Each bag leak detection system used to comply with...

40 CFR 60.256 - Continuous monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

....256 Section 60.256 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... rates of 25 Mg (28 tons) per year or more, a bag leak detection system according to the requirements in... performance test on an operating day average basis. (c) Each bag leak detection system used to comply with...

40 CFR 60.256 - Continuous monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

....256 Section 60.256 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... rates of 25 Mg (28 tons) per year or more, a bag leak detection system according to the requirements in... performance test on an operating day average basis. (c) Each bag leak detection system used to comply with...

40 CFR 60.256 - Continuous monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

....256 Section 60.256 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... rates of 25 Mg (28 tons) per year or more, a bag leak detection system according to the requirements in... performance test on an operating day average basis. (c) Each bag leak detection system used to comply with...

75 FR 56597 - University of Wisconsin; University of Wisconsin Nuclear Reactor Environmental Assessment and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

...,000 gallons being typical. The licensee maintains a pool leak surveillance program. The pool water leak surveillance program continues to monitor the pool water evaporation rate, the pool water make-up volume, and pool water radioactivity. The pool leak surveillance program indicated that approximately 2...

40 CFR 63.1036 - Alternative means of emission limitation: Batch processes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... SOURCE CATEGORIES (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards... leaks. The owner or operator may switch among the alternatives provided the change is documented as... shall be pressure-tested for leaks before regulated material is first fed to the equipment and the...

40 CFR 63.8600 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuity, and all mechanical connections for leakage. (d) For each pH measurement device, you must meet the... integrity and all electrical connections for continuity. (e) For each bag leak detection system, you must... leak detection system must be installed, calibrated, operated, and maintained according to the “Fabric...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2011 CFR

2011-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2012 CFR

2012-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2014 CFR

2014-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

Combined Endoscopic Transorbital and Endonasal Repair of High Flow Orbital Apex/Middle Fossa Cerebrospinal Fluid Leak with a Nasoseptal Flap.

PubMed

Lucke-Wold, Brandon; Mendez, Gustavo; Cua, David; Akins, Paul; Gillham, Haley; Ciporen, Jeremy

2018-01-01

High flow orbital apex or middle fossa cerebrospinal fluid (CSF) leaks can be life threatening and complex to repair. These leaks associated with large dural defects are most commonly repaired with an open temporalis muscle patch or free flaps, but these flaps do not always stop the leak. A 65-year-old patient presented two years after orbital exenteration and radiation for squamous cell carcinoma. He developed multi-organism meningitis and pneumocephalus secondary to a large high-flow orbital apex/middle fossa CSF leak. To repair the leak, a combined endoscopic transorbital/endonasal approach with pedicled nasospetal flap and dermis fat graft was used. We describe the unique endoscopic technique that was used to treat the life threatening high flow orbital apex/middle fossa CSF leak. The technique allowed the use of the transposed pedicled flap, which is an alternative to the free flap in controlling CSF leak. Cisternogram post-operatively and clinical exam confirmed resolution of CSF leak. Although a critically ill patient at admission with a modified Rankin scale (MRS) of 5, he was discharged home on continued IV antibiotic therapy with a MRS of 3. Endoscopic evaluation at three months after treatment showed the effectiveness of the flap and he continued to improve clinically. This is the first case to describe a combined endoscopic transorbital and endonasal repair of high flow orbital apex/middle fossa CSF leak with a pedicled nasoseptal flap. These techniques can be utilized during initial reconstruction after orbital exenteration or as a salvage flap.

[External lumbar drainage with volumetric continuing infusion pump in patients with cerebrospinal fluid leak. A case series].

PubMed

Manso Melgosa, Ana Belén; García Gutiérrez, Helena; Fernández Porras, Mónica; Castrillo Manero, Ana Berta; Pérez Marijuán, Belén

To describe the incidence and complications arising in a number of cases of patients with cerebrospinal fluid leak treated by external lumbar drainage with infusion pump (IP) volumetric continuous from 2001 to 2014. Quantify cerebrospinal fluid leak closed by lumbar drainage with IP. Retrospective descriptive case series study. patients undergoing transsphenoidal pituitary surgery, Chiari surgery and laminectomy, that developed postoperative cerebrospinal fluid leak treated with continuous external lumbar drainage by IP. age, sex, type of intervention, variables related to the practice of the pump and complications. Average and medians were calculated for quantitative variables, frequencies and percentages for qualitative. Sample: 11 subjects. Incidence in running IP: disconnection, occlusion and acoustic alarm activation. Most frequently complication is headache; a case of pneumocephalus. The small number of subjects and the heterogeneity of these do not allow for comparison or establishing associations between variables. The resolution of the cerebrospinal fluid leak with continuous IP is lower in this study than others, and may be influenced by the small number of subjects. It should be noted the frequent activation of the pump alarm for no apparent cause. Protocol would be developed for preparing the IP team to reduce the acoustic alarm activation, and would make a prospective multicenter study. Copyright © 2016 Elsevier España, S.L.U. All rights reserved.

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2010 CFR

2010-07-01

... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as... detection system for each exhaust stack of the fabric filter. (2) Each bag leak detection system must be... specifications and recommendations. (3) The bag leak detection system must be certified by the manufacturer to be...

40 CFR 60.2730 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuously operate a bag leak detection system as specified in paragraphs (b)(1) through (8) of this section. (1) You must install and operate a bag leak detection system for each exhaust stack of the fabric filter. (2) Each bag leak detection system must be installed, operated, calibrated, and maintained in a...

40 CFR 63.1453 - How do I demonstrate continuous compliance with the emission limitations, work practice standards...

Code of Federal Regulations, 2010 CFR

2010-07-01

... percent opacity. (c) Baghouses. For each baghouse subject to the operating limit for the bag leak... that the bag leak detection system alarm does not sound for more than 5 percent of the operating time... malfunction of the bag leak detection system are not included in the calculation. (ii) Alarms that occur...

40 CFR 65.102 - Alternative means of emission limitation.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.102 Alternative means of emission... equipment leaks of a regulated material may apply to the Administrator for approval of an alternative means...

The International Space Station 2B Photovoltaic Thermal Control System (PVTCS) Leak: An Operational History

NASA Technical Reports Server (NTRS)

Vareha, Anthony N.

2014-01-01

As early as 2004, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B electrical power channel began slowly leaking ammonia overboard. Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity (EVA) during the STS-134 Space Shuttle mission. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. In mid-2012, the leak rate increased from 1.5lbm/year to approximately 5lbm/year. As a result, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to an adjacent dormant thermal control system. This EVA, US EVA 20, was successfully executed on November 1, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a different radiator than what the system was designed to utilize. Data monitoring over the next several months showed that the isolated radiator had not been leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the crew noticing the leak, US EVA 21 was in progress to replace the coolant pump - the only remaining replaceable leak source. This was successful, and telemetry monitoring has shown that indeed the coolant pump was the leak source and was thus isolated from the running 2B PVTCS. This paper will explore the management of the 2B PVTCS leak from the operations perspective.

Intrapleural instillation of autologous blood for persistent air leak in spontaneous pneumothorax in patients with advanced chronic obstructive pulmonary disease.

PubMed

Cao, Guo qiang; Kang, Jun; Wang, Fangwen; Wang, Hucheng

2012-05-01

We evaluated the safety and efficacy of increasing doses of autologous blood patch pleurodesis in treating persistent air leaks in patients with advanced chronic obstructive pulmonary disease (COPD). Forty-four patients with COPD and spontaneous pneumothorax (SP) on the 7th day after intercostal tube drainage were randomly assigned to 4 groups, with 11 patients in each group. Groups A, B, and C were given increasing doses of autologous blood--ie, 0.5 mL/kg, 1 mL/kg, 2 mL/kg, respectively--whereas group D was given 1 mL/kg normal saline only. The procedure was repeated if the air leak persisted on postoperative days 9 and 11. Patients in group D crossed over and received autologous blood as in group B if the air leak was still present on the 13th postoperative day. No patient died in the study. The air leak was sealed by the 13th postoperative day only in patients with air leaks smaller than size 3. Air leaks were classified as 0 to 3 [12], ie, size 0=no air leak; size 1=air leak on vigorous coughing only; size 2=small continuous air leak on gentle respiration; and size 3=large continuous air leak on gentle respiration. The success rates by the 13th postoperative day in groups A, B, C, and D were 27%, 82%, 82%, and 9%, respectively. The success rate (82%) was significantly higher in groups B and C than in group A (p=0.003) and D (p>0.01). Using autologous blood to treat secondary spontaneous pneumothorax (SSP) in patients with advanced COPD is easy, safe, and effective. The dose of blood required for autologous blood patch pleurodesis should be dependent on the body weight, and 1 mL/kg blood may be efficient. Copyright © 2012 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

PubMed Central

Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Riva, Enrico Da; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

2014-01-01

We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

Method of locating a leaking fuel element in a fast breeder power reactor

DOEpatents

Honekamp, John R.; Fryer, Richard M.

1978-01-01

Leaking fuel elements in a fast reactor are identified by measuring the ratio of .sup.134 Xe to .sup.133 Xe in the reactor cover gas following detection of a fuel element leak, this ratio being indicative of the power and burnup of the failed fuel element. This procedure can be used to identify leaking fuel elements in a power breeder reactor while continuing operation of the reactor since the ratio measured is that of the gases stored in the plenum of the failed fuel element. Thus, use of a cleanup system for the cover gas makes it possible to identify sequentially a multiplicity of leaking fuel elements without shutting the reactor down.

Method and apparatus for container leakage testing

DOEpatents

Kronberg, James W.

1995-01-01

An apparatus for use in one-hundred percent leak testing of food containers used in conjunction with a tracer gas. The apparatus includes a shell with entrance and exit air locks to create a controlled atmosphere through which a series of containers is conveyed by a conveyor belt. The pressure in the shell is kept lower than the pressure in the containers and the atmosphere is made to flow with the containers so that a tracer gas placed in the packages before sealing them will leak more readily, but the leaked tracer gas will remain associated with the leaking package as it moves through the shell. The leaks are detected with a sniffer probe in fluid communication with a gas chromatograph. The gas chromatograph issues a signal when it detects a leak to an ejector that will eject the leaking container from the conveyor. The system is timed so that the series of containers can move continuously into and out of the shell, past the probe and the ejector, without stopping, yet each package is tested for leaks and removed if leaking.

New acoustic techniques for leak detection in fossil fuel plant components

NASA Astrophysics Data System (ADS)

Parini, G.; Possa, G.

Two on-line acoustic monitoring techniques for leak detection in feedwater preheaters and boilers of fossil fuel power plants are presented. The leak detection is based on the acoustic noise produced by the turbulent leak outflow. The primary sensors are piezoelectric pressure transducers, installed near the feedwater preheater inlets, in direct contact with the water, or mounted on boiler observation windows. The frequency band of the auscultation ranges from a few kHz, to 10 to 15 kHz. The signals are characterized by their rms value, continuously recorded by means of potentiometric strip chart recorders. The leak occurrence is signalled by the signal rms overcoming predetermined threshold levels. Sensitivity, reliability, acceptance in plant control practice, and costs-benefits balance are satisfactory.

SIXTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2011-08-31

A series of experiments to monitor the aging performance of Viton{reg_sign} GLT O-rings used in the Model 9975 package has been ongoing for seven years at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 F. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 F. High temperature aging continues formore » 33 GLT O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 F and higher temperatures, and in 7 fixtures aging at 300 F. No failures have yet been observed in GLT O-ring fixtures aging at 200 F for 41-60 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 F will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging within the past year at an intermediate temperature of 270 F, with hopes that they may leak before the 200 F fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200-300 F. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 F. No failures have yet been observed in GLT-S O-ring fixtures aging at 200-300 F for up to 26 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the Orings displayed a compression set ranging from 51-96%. This is greater than seen to date for packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350-400 F). However, at 300 F, the room temperature leak test failures to date experienced longer aging times than predicted by the CSR-based model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 F will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining fixtures.« less

Performance of Leak Compensation in All-Age ICU Ventilators During Volume-Targeted Neonatal Ventilation: A Lung Model Study.

PubMed

Itagaki, Taiga; Bennett, Desmond J; Chenelle, Christopher T; Fisher, Daniel F; Kacmarek, Robert M

2017-01-01

Volume-targeted ventilation is increasingly used in low birthweight infants because of the potential for reducing volutrauma and avoiding hypocapnea. However, it is not known what level of air leak is acceptable during neonatal volume-targeted ventilation when leak compensation is activated concurrently. Four ICU ventilators (Servo-i, PB980, V500, and Avea) were compared in available invasive volume-targeted ventilation modes (pressure control continuous spontaneous ventilation [PC-CSV] and pressure control continuous mandatory ventilation [PC-CMV]). The Servo-i and PB980 were tested with (+) and without (-) their proximal flow sensor. The V500 and Avea were tested with their proximal flow sensor as indicated by their manufacturers. An ASL 5000 lung model was used to simulate 4 neonatal scenarios (body weight 0.5, 1, 2, and 4 kg). The ASL 5000 was ventilated via an endotracheal tube with 3 different leaks. Two minutes of data were collected after each change in leak level, and the asynchrony index was calculated. Tidal volume (V T ) before and after the change in leak was assessed. The differences in delivered V T between before and after the change in leak were within ±5% in all scenarios with the PB980 (-/+) and V500. With the Servo-i (-/+), baseline V T was ≥10% greater than set V T during PC-CSV, and delivered V T markedly changed with leak. The Avea demonstrated persistent high V T in all leak scenarios. Across all ventilators, the median asynchrony index was 1% (interquartile range 0-27%) in PC-CSV and 1.8% (0-45%) in PC-CMV. The median asynchrony index was significantly higher in the Servo-i (-/+) than in the PB980 (-/+) and V500 in 1 and 2 kg scenarios during PC-CSV and PC-CMV. The PB980 and V500 were the only ventilators to acclimate to all leak scenarios and achieve targeted V T . Further clinical investigation is needed to validate the use of leak compensation during neonatal volume-targeted ventilation. Copyright © 2017 by Daedalus Enterprises.

Functionalized multi-walled carbon nanotube based sensors for distributed methane leak detection

EPA Science Inventory

This paper presents a highly sensitive, energy efficient and low-cost distributed methane (CH4) sensor system (DMSS) for continuous monitoring, detection and localization of CH4 leaks in natural gas infrastructure such as transmission and distribution pipelines, wells, and produc...

Confidence Leak in Perceptual Decision Making.

PubMed

Rahnev, Dobromir; Koizumi, Ai; McCurdy, Li Yan; D'Esposito, Mark; Lau, Hakwan

2015-11-01

People live in a continuous environment in which the visual scene changes on a slow timescale. It has been shown that to exploit such environmental stability, the brain creates a continuity field in which objects seen seconds ago influence the perception of current objects. What is unknown is whether a similar mechanism exists at the level of metacognitive representations. In three experiments, we demonstrated a robust intertask confidence leak-that is, confidence in one's response on a given task or trial influencing confidence on the following task or trial. This confidence leak could not be explained by response priming or attentional fluctuations. Better ability to modulate confidence leak predicted higher capacity for metacognition as well as greater gray matter volume in the prefrontal cortex. A model based on normative principles from Bayesian inference explained the results by postulating that observers subjectively estimate the perceptual signal strength in a stable environment. These results point to the existence of a novel metacognitive mechanism mediated by regions in the prefrontal cortex. © The Author(s) 2015.

Cerebrospinal fluid otorhinorrhea due to cochlear dysplasias.

PubMed

Syal, Rajan; Tyagi, Isha; Goyal, Amit

2005-07-01

Cochlear dysplasia associated with defect in stapes footplate can be a cause of cerebrospinal fluid leak. Repair of cerebrospinal fluid leak in these cases is usually done by packing the vestibule with muscle or fascia. This traditional method of repair has 30-60% failure rate. Cerebrospinal fluid leak in four such patients was successfully repaired using multiple layer packing of vestibule, reinforced by pedicle temporalis muscle graft. Intraoperatively continuous lumbar drain was done. Magnetic resonance imaging of inner ear using 3D FSE T2WI and 3D FIESTA sequences was found helpful noninvasive investigation to localize site and route of cerebrospinal fluid leak.

Acceleration of block-matching algorithms using a custom instruction-based paradigm on a Nios II microprocessor

NASA Astrophysics Data System (ADS)

González, Diego; Botella, Guillermo; García, Carlos; Prieto, Manuel; Tirado, Francisco

2013-12-01

This contribution focuses on the optimization of matching-based motion estimation algorithms widely used for video coding standards using an Altera custom instruction-based paradigm and a combination of synchronous dynamic random access memory (SDRAM) with on-chip memory in Nios II processors. A complete profile of the algorithms is achieved before the optimization, which locates code leaks, and afterward, creates a custom instruction set, which is then added to the specific design, enhancing the original system. As well, every possible memory combination between on-chip memory and SDRAM has been tested to achieve the best performance. The final throughput of the complete designs are shown. This manuscript outlines a low-cost system, mapped using very large scale integration technology, which accelerates software algorithms by converting them into custom hardware logic blocks and showing the best combination between on-chip memory and SDRAM for the Nios II processor.

40 CFR 63.1410 - Equipment leak provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission... leak provisions. The owner or operator of each affected source shall comply with the requirements of 40... conflicts between the due dates for reports presented in 40 CFR part 63, subpart SS and this subpart...

COPPER PITTING CORROSION AND PINHOLE LEAKS: A CASE STUDY

EPA Science Inventory

Localized corrosion, or "pitting", of copper drinking water pipe continues is a problem for many water utilities and their customers. Extreme attack leads to pinhole leaks that can potentially lead to water damage, mold growth, and costly repairs for the homeowners, as well as th...

49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance... pipe in size. (4) If the leak is on a submerged offshore pipeline or submerged pipeline in inland...

Current and emerging laser sensors for greenhouse gas sensing and leak detection

NASA Astrophysics Data System (ADS)

Frish, Michael B.

2014-05-01

To reduce atmospheric accumulation of the greenhouse gases methane and carbon dioxide, networks of continuously operating sensors that monitor and map their sources are desirable. In this paper, we discuss advances in laser-based open-path leak detectors, as well as technical and economic challenges inhibiting widespread sensor deployment for "ubiquitous monitoring". We describe permanently-installed, wireless, solar-powered sensors that overcome previous installation and maintenance difficulties while providing autonomous real-time leak reporting without false alarms.

40 CFR 63.7113 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... continuity, and all mechanical connections for leakage. (d) For each bag leak detection system (BLDS), you... mechanical connections for leakage. (c) For each pressure measurement device, you must meet the requirements... instrumentation and alarm. (6) Bag leak detection systems must be installed, operated, adjusted, and maintained...

40 CFR 63.8450 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... electrical connections for continuity, and all mechanical connections for leakage. (d) For each pH... bag leak detection system, you must meet the requirements in paragraphs (e)(1) through (11) of this section. (1) Each triboelectric bag leak detection system must be installed, calibrated, operated, and...

Makalu: fast recoverable allocation of non-volatile memory

DOE PAGES

Bhandari, Kumud; Chakrabarti, Dhruva R.; Boehm, Hans-J.

2016-10-19

Byte addressable non-volatile memory (NVRAM) is likely to supplement, and perhaps eventually replace, DRAM. Applications can then persist data structures directly in memory instead of serializing them and storing them onto a durable block device. However, failures during execution can leave data structures in NVRAM unreachable or corrupt. In this paper, we present Makalu, a system that addresses non-volatile memory management. Makalu offers an integrated allocator and recovery-time garbage collector that maintains internal consistency, avoids NVRAM memory leaks, and is efficient, all in the face of failures. We show that a careful allocator design can support a less restrictive andmore » a much more familiar programming model than existing persistent memory allocators. Our allocator significantly reduces the per allocation persistence overhead by lazily persisting non-essential metadata and by employing a post-failure recovery-time garbage collector. Experimental results show that the resulting online speed and scalability of our allocator are comparable to well-known transient allocators, and significantly better than state-of-the-art persistent allocators.« less

Makalu: fast recoverable allocation of non-volatile memory

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

Bhandari, Kumud; Chakrabarti, Dhruva R.; Boehm, Hans-J.

Byte addressable non-volatile memory (NVRAM) is likely to supplement, and perhaps eventually replace, DRAM. Applications can then persist data structures directly in memory instead of serializing them and storing them onto a durable block device. However, failures during execution can leave data structures in NVRAM unreachable or corrupt. In this paper, we present Makalu, a system that addresses non-volatile memory management. Makalu offers an integrated allocator and recovery-time garbage collector that maintains internal consistency, avoids NVRAM memory leaks, and is efficient, all in the face of failures. We show that a careful allocator design can support a less restrictive andmore » a much more familiar programming model than existing persistent memory allocators. Our allocator significantly reduces the per allocation persistence overhead by lazily persisting non-essential metadata and by employing a post-failure recovery-time garbage collector. Experimental results show that the resulting online speed and scalability of our allocator are comparable to well-known transient allocators, and significantly better than state-of-the-art persistent allocators.« less

A method for simulating the entire leaking process and calculating the liquid leakage volume of a damaged pressurized pipeline.

PubMed

He, Guoxi; Liang, Yongtu; Li, Yansong; Wu, Mengyu; Sun, Liying; Xie, Cheng; Li, Feng

2017-06-15

The accidental leakage of long-distance pressurized oil pipelines is a major area of risk, capable of causing extensive damage to human health and environment. However, the complexity of the leaking process, with its complex boundary conditions, leads to difficulty in calculating the leakage volume. In this study, the leaking process is divided into 4 stages based on the strength of transient pressure. 3 models are established to calculate the leaking flowrate and volume. First, a negative pressure wave propagation attenuation model is applied to calculate the sizes of orifices. Second, a transient oil leaking model, consisting of continuity, momentum conservation, energy conservation and orifice flow equations, is built to calculate the leakage volume. Third, a steady-state oil leaking model is employed to calculate the leakage after valves and pumps shut down. Moreover, sensitive factors that affect the leak coefficient of orifices and volume are analyzed respectively to determine the most influential one. To validate the numerical simulation, two types of leakage test with different sizes of leakage holes were conducted from Sinopec product pipelines. More validations were carried out by applying commercial software to supplement the experimental insufficiency. Thus, the leaking process under different leaking conditions are described and analyzed. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of volume and leak measurements during CPAP using a neonatal lung model.

PubMed

Fischer, H S; Roehr, C C; Proquitté, H; Wauer, R R; Schmalisch, G

2008-01-01

Although several commercial devices are available which allow tidal volume and air leak monitoring during continuous positive airway pressure (CPAP) in neonates, little is known about their measurement accuracy and about the influence of air leaks on volume measurement. The aim of this in vitro study was the validation of volume and leak measurement under CPAP using a commercial ventilatory device, taking into consideration the clinical conditions in neonatology. The measurement accuracy of the Leoni ventilator (Heinen & Löwenstein, Germany) was investigated both in a leak-free system and with leaks simulated using calibration syringes (2-10 ml, 20-100 ml) and a mechanical lung model. Open tubes of variable lengths were connected for leak simulation. Leak flow was measured with the flow-through technique. In a leak-free system the mean relative volume error +/-SD was 3.5 +/- 2.6% (2-10 ml) and 5.9 +/- 0.7% (20-60 ml), respectively. The influence of CPAP level, driving flow, respiratory rate and humidification of the breathing gas on the volume error was negligible. However, an increasing F(i)O(2) caused the measured tidal volume to increase by up to 25% (F(i)O(2) = 1.0). The relative error +/- SD of the leak measurements was -0.2 +/- 11.9%. For leaks > 19%, measured tidal volume was underestimated by more than 10%. In conclusion, the present in vitro study showed that the Leoni allowed accurate volume monitoring under CPAP conditions similar to neonates. Air leaks of up to 90% of patient flow were reliably detected. For an F(i)O(2) > 0.4 and for leaks > 19%, a numerical correction of the displayed volume should be performed.

Physical implication of transition voltage in organic nano-floating-gate nonvolatile memories

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

Wang, Shun; Gao, Xu, E-mail: wangsd@suda.edu.cn, E-mail: gaoxu@suda.edu.cn; Zhong, Ya-Nan

High-performance pentacene-based organic field-effect transistor nonvolatile memories, using polystyrene as a tunneling dielectric and Au nanoparticles as a nano-floating-gate, show parallelogram-like transfer characteristics with a featured transition point. The transition voltage at the transition point corresponds to a threshold electric field in the tunneling dielectric, over which stored electrons in the nano-floating-gate will start to leak out. The transition voltage can be modulated depending on the bias configuration and device structure. For p-type active layers, optimized transition voltage should be on the negative side of but close to the reading voltage, which can simultaneously achieve a high ON/OFF ratio andmore » good memory retention.« less

Understanding Natural Gas Methane Leakage from Buried Pipelines as Affected by Soil and Atmospheric Conditions - Field Scale Experimental and Modeling Study

NASA Astrophysics Data System (ADS)

Smits, K. M.; Mitton, M.; Moradi, A.; Chamindu, D. K.

2017-12-01

Reducing the amount of leaked natural gas (NG) from pipelines from production to use has become a high priority in efforts to cut anthropogenic emissions of methane. In addition to environmental impacts, NG leakage can cause significant economic losses and safety failures such as fires and explosions. However, tracking and evaluating NG pipeline leaks requires a better understanding of the leak from the source to the detector as well as more robust quantification methods. Although recent measurement-based approaches continue to make progress towards this end, efforts are hampered due to the complexity of leakage scenarios. Sub- surface transport of leaked NG from pipelines occurs through complex transport pathways due to soil heterogeneities and changes in soil moisture. Furthermore, it is affected by variable atmospheric conditions such as winds, frontal passages and rain. To better understand fugitive emissions from NG pipelines, we developed a field scale testbed that simulates low pressure gas leaks from pipe buried in soil. The system is equipped with subsurface and surface sensors to continuously monitor changes in soil and atmospheric conditions (e.g. moisture, pressure, temperature) and methane concentrations. Using this testbed, we are currently conducting a series of gas leakage experiments to study of the impact of subsurface (e.g. soil moisture, heterogeneity) and atmospheric conditions (near-surface wind and temperature) on the detected gas signals and establish the relative importance of the many pathways for methane migration between the source and the sensor location. Accompanying numerical modeling of the system using the multiphase transport simulator TOUGH2-EOS7CA demonstrates the influence of leak location and direction on gas migration. These findings will better inform leak detectors of the leak severity before excavation, aiding with safety precautions and work order categorization for improved efficiency.

SEVENTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2012-08-30

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 54-72 months, which is still bounding to O-ring temperatures during storage in K-Area Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 30 - 36 months. For O-ring fixtures that have failed the room temperature leak test and been disassembled, the O-rings displayed a compression set ranging from 51 – 96%. This is greater than seen to date for any packages inspected during KAC field surveillance (24% average). For GLT O-rings, separate service life estimates have been made based on the O-ring fixture leak test data and based on compression stress relaxation (CSR) data. These two predictive models show reasonable agreement at higher temperatures (350 – 400 ºF). However, at 300 ºF, the room temperature leak test failures to date experienced longer aging times than predicted by the CSRbased model. This suggests that extrapolations of the CSR model predictions to temperatures below 300 ºF will provide a conservative prediction of service life relative to the leak rate criterion. Leak test failure data at lower temperatures are needed to verify this apparent trend. Insufficient failure data exist currently to perform a similar comparison for GLT-S O-rings. Aging and periodic leak testing will continue for the remaining PCV O-ring fixtures.« less

Digital air leak monitoring after lobectomy for primary lung cancer in patients with moderate COPD: can a fast-tracking algorithm reduce postoperative costs and complications?

PubMed

Filosso, P L; Ruffini, E; Solidoro, P; Molinatti, M; Bruna, M C; Oliaro, A

2010-06-01

Prolonged air leaks remain one of the most important complication after pulmonary resection. The aim of this study was to test a new fast-track chest tube removal protocol using a new drainage system, which digitally records postoperative air leaks, compared to the traditional one, with subjective visual air leak assessment. Patients with moderate COPD undergoing lobectomy for primary lung cancer at the Department of Thoracic Surgery of the University of Torino were randomised in two groups with different chest drainage systems and different removal protocols: in Group A the drainage was removed after digitally recordered measurement of air leaks; in Group B the tube was removed according to the air leaks visualization by bubbling in the water column. The following variables were evaluated: first and second drainage removal day; overall hospital length of stay; overall hospitalization costs. First and second drainages were removed sooner in those patients with the digital drainage system. An earlier drainage removal is associated with significative reduction in hospital length of stay and overall hospitalization costs. The digital and continuous air leak measurement reduces the hospital length of stay by a more accurate and reproductive air leaks measurement. Further studies are mandatory to corroborate our preliminary results.

40 CFR 63.7525 - What are my monitoring, installation, operation, and maintenance requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... tolerance of 1.27 centimeters of water or a transducer with a minimum tolerance of 1 percent of the pressure... use a fabric filter bag leak detection system to comply with the requirements of this subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as specified in...

Operational Exercise Integration Recommendations for DoD Cyber Ranges

DTIC Science & Technology

2015-08-05

be the precision and recall of a security information and event management (SIEM) system ’s notifications of unauthorized access to that directory...network traffic, port scanning Deplete Resources TCP flooding, memory leak exploitation Injection Cross-site scripting attacks, SQL injection Deceptive...requirements for personnel development; tactics, techniques, and procedures (TTPs) devel- opment; and mission rehearsals . While unique in their own

Final Report: Correctness Tools for Petascale Computing

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

Mellor-Crummey, John

2014-10-27

In the course of developing parallel programs for leadership computing systems, subtle programming errors often arise that are extremely difficult to diagnose without tools. To meet this challenge, University of Maryland, the University of Wisconsin—Madison, and Rice University worked to develop lightweight tools to help code developers pinpoint a variety of program correctness errors that plague parallel scientific codes. The aim of this project was to develop software tools that help diagnose program errors including memory leaks, memory access errors, round-off errors, and data races. Research at Rice University focused on developing algorithms and data structures to support efficient monitoringmore » of multithreaded programs for memory access errors and data races. This is a final report about research and development work at Rice University as part of this project.« less

The effect of mouth leak and humidification during nasal non-invasive ventilation.

PubMed

Tuggey, Justin M; Delmastro, Monica; Elliott, Mark W

2007-09-01

Poor mask fit and mouth leak are associated with nasal symptoms and poor sleep quality in patients receiving domiciliary non-invasive ventilation (NIV) through a nasal mask. Normal subjects receiving continuous positive airways pressure demonstrate increased nasal resistance following periods of mouth leak. This study explores the effect of mouth leak during pressure-targeted nasal NIV, and whether this results in increased nasal resistance and consequently a reduction in effective ventilatory support. A randomised crossover study of 16 normal subjects was performed on separate days. Comparison was made of the effect of 5 min of mouth leak during daytime nasal NIV with and without heated humidification. Expired tidal volume (V(T)), nasal resistance (R(N)), and patient comfort were measured. Mean change (Delta) in V(T) and R(N) were significantly less following mouth leak with heated humidification compared to the without (DeltaV(T) -36+/-65 ml vs. -88+/-50 ml, p<0.001; DeltaR(N) +0.9+/-0.4 vs. +2.0+/-0.7 cm H(2)O l s(-1), p<0.001). Baseline comfort was worse without humidification (5.3+/-0.4 vs. 6.2+/-0.4, p<0.01), and only deteriorated following mouth leak without humidification. In normal subjects, heated humidification during nasal NIV attenuates the adverse effects of mouth leak on effective tidal volume, nasal resistance and improves overall comfort. Heated humidification should be considered as part of an approach to patients who are troubled with nasal symptoms, once leak has been minimised.

40 CFR Table 6 to Subpart Kkkkk of... - Continuous Compliance With Emission Limitations and Work Practice Standards

Code of Federal Regulations, 2010 CFR

2010-07-01

... or DLS/FF i. If you use a bag leak detection system, initiating corrective action within 1 hour of a bag leak detection system alarm and completing corrective actions in accordance with your OM&M plan... established during the performance test; and iv. If chemicals are added to the scrubber water, collecting the...

Mothering and Professing in the Ivory Tower: A Review of the Literature and a Call for a Research Agenda

ERIC Educational Resources Information Center

Eversole, Barbara A. W.; Harvey, Ashley M.; Zimmerman, Toni S.

2007-01-01

Although women outnumber men in receiving PhDs, the pipeline to tenure track positions leaks, particularly for mothers. In fact, the leak continues into the granting of tenure and the achievement of promotion. While having children increases a man's chances at attaining tenure and advancement, mothering decreasing a woman's chances. Implications…

Health Hazard Evaluation Report HETA 84-145-1604, Porter Memorial Hospital, Valparaiso, Indiana. [Anesthetic gases and ethylene oxide

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

Behrens, V.; Burroughs, G.E.; Crandall, M.

1985-07-01

Environmental and breathing-zone samples were analyzed for nitrous oxide, halogenated anesthetic gases, and ethylene-oxide at Porter Memorial Hospital, Valparaiso, Indiana in April, 1984. The evaluation was requested by the Indiana Occupational Safety and Health Administration to investigate the exposure of operating room personnel to anesthetic gases and central supply employees to ethylene-oxide. The authors conclude that some of the operating room personnel are overexposed to halogenated anesthetic gases and nitrous-oxide. Recommendations include performing better maintenance of the anesthesia equipment, improving the work practices of the anesthesiologists, and periodically checking the ethylene-oxide sterilizer system for leaks.

The ISS 2B PVTCS Ammonia Leak: An Operational History

NASA Technical Reports Server (NTRS)

Vareha, Anthony

2014-01-01

In 2006, the Photovoltaic Thermal Control System (PVTCS) for the International Space Station's 2B power channel began leaking ammonia at a rate of approximately 1.5lbm/year (out of a starting approximately 53lbm system ammonia mass). Initially, the operations strategy was "feed the leak," a strategy successfully put into action via Extra Vehicular Activity during the STS-134 mission. During this mission the system was topped off with ammonia piped over from a separate thermal control system. This recharge was to have allowed for continued power channel operation into 2014 or 2015, at which point another EVA would have been required. Without these periodic EVAs to refill the 2B coolant system, the channel would eventually leak enough fluid as to risk pump cavitation and system failure, resulting in the loss of the 2B power channel - the most critical of the Space Station's 8 power channels. In mid-2012, the leak rate increased to approximately 5lbm/year. Once discovered, an EVA was planned and executed within a 5 week timeframe to drastically alter the architecture of the PVTCS via connection to a dormant thermal control system not intended to be utilized as anything other than spare components. The purpose of this rerouting of the TCS was to increase system volume and to isolate the photovoltaic radiator, thought to be the likely leak source. This EVA was successfully executed on November 1st, 2012 and left the 2B PVTCS in a configuration where the system was now being adequately cooled via a totally different radiator than what the system was designed to utilize. Unfortunately, data monitoring over the next several months showed that the isolated radiator was not leaking, and the system itself continued to leak steadily until May 9th, 2013. It was on this day that the ISS crew noticed the visible presence of ammonia crystals escaping from the 2B channel's truss segment, signifying a rapid acceleration of the leak from 5lbm/year to 5lbm/day. Within 48 hours of the crew noticing the leak, an EVA was in progress to replace the coolant pump - the only other replaceable leak source. This paper will explore the management of the 2B PVTCS leak from the operations perspective. It will discuss the methodology of performing the STS-134 refill, the considerations and contingency plans which went into the architectural overhaul of the system in 2012, and the unprecedented effort which went into the EVA response to the visible leak of May 2013. In particular the paper will focus on the techniques utilized by flight controllers to monitor the system health and to respond to such instances as the rapid May 2013 leak by putting the electrical system in a safe configuration for loss of cooling, and will use recorded telemetry of these events to describe system response to EVA crew and ground actions. It will discuss the innovative design for redundancy of the integrated truss structure's cooling systems which allowed for this leak to be managed with minimal impact to other ISS operations and electrical services, contrasted against the real unintended operations consequences of utilizing the flexibility of the spacecraft's design in this manner. The paper will discuss how the training of the crew and flight controller personnel has adapted to the changing architecture of the power system and the unpredictable nature of the 2B leak.

NINTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W.

2014-08-06

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23 GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The earliest 300 °F GLT O-ring fixture failure was observed at 34 months. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 72 - 96 months, which bounds O-ring temperatures anticipated during storage in K-Area Complex (KAC). Based on expectations that the 200 ºF fixtures will remain leak-tight for a significant period yet to come, 2 additional fixtures began aging in 2011 at 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures, thus providing additional time to failure data. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 54 - 57 months. No additional O-ring failures have been observed since the last interim report was issued. Aging and periodic leak testing will continue for the remaining PCV fixtures. Additional irradiation of several fixtures is recommended to maintain a balance between thermal and radiation exposures similar to that experienced in storage, and to show the degree of consistency of radiation response between GLT and GLT-S O-rings.« less

Treatment of esophageal anastomotic leakage with self-expanding metal stents: analysis of risk factors for treatment failure

PubMed Central

Persson, Saga; Rouvelas, Ioannis; Kumagai, Koshi; Song, Huan; Lindblad, Mats; Lundell, Lars; Nilsson, Magnus; Tsai, Jon A.

2016-01-01

Background and study aim: The endoscopic placement of self-expandable metallic esophageal stents (SEMS) has become the preferred primary treatment for esophageal anastomotic leakage in many institutions. The aim of this study was to investigate possible risk factors for failure of SEMS-based therapy in patients with esophageal anastomotic leakage. Patients and methods: Beginning in 2003, all patients with an esophageal leak were initially approached and assessed for temporary closure with a SEMS. Until 2014, all patients at the Karolinska University Hospital with a leak from an esophagogastric or esophagojejunal anastomosis were identified. Data regarding the characteristics of the patients and leaks and the treatment outcomes were compiled. Failure of the SEMS treatment strategy was defined as death due to the leak or a major change in management strategy. The risk factors for treatment failure were analyzed with simple and multivariable logistic regression statistics. Results: A total of 447 patients with an esophagogastric or esophagojejunal anastomosis were identified. Of these patients, 80 (18 %) had an anastomotic leak, of whom 46 (58 %) received a stent as first-line treatment. In 29 of these 46 patients, the leak healed without any major change in treatment strategy. Continuous leakage after the application of a stent, decreased physical performance preoperatively, and concomitant esophagotracheal fistula were identified as independent risk factors for failure with multivariable logistic regression analysis. Conclusion: Stent treatment for esophageal anastomotic leakage is successful in the majority of cases. Continuous leakage after initial stent insertion, decreased physical performance preoperatively, and the development of an esophagotracheal fistula decrease the probability of successful treatment. PMID:27092321

Occurrence of occult CSF leaks during standard FESS procedures.

PubMed

Bucher, S; Kugler, A; Probst, E; Epprecht, L; Stadler, R S; Holzmann, D; Soyka, M B

2018-03-18

To determine the incidence of occult cerebrospinal fluid leaks (CSF) after functional endoscopic sinus surgery (FESS) and to evaluate the diagnostic performance of beta2-transferrin in blood-contaminated conditions. Prospective cohort study. An analysis of 57 intraoperative samples using hydrogel 6 beta2-transferrin assay after FESS was undertaken. In case of CSF positive samples and continuing rhinorrhea, reanalysis after more than 1 year was conducted. In-vivo analysis of a primary spontaneous CSF leak sample took place to verify difficulties in detecting beta2-transferrin in blood-contaminated settings. Own titrations were performed to evaluate detection limits of CSF by beta2-transferrin and beta-trace protein assays in these settings. An incidence of 13% for occult CSF leaks after FESS was found. In blood-contaminated conditions, routine beta2-transferrin assays showed low sensitivity. In over 1 year follow-up, all samples were negative for CSF and none of them developed clinical relevant CSF leaks or meningitis. Occult and clinically irrelevant CSF leaks do occur in a significant proportion of patients during and shortly after FESS. Intra- and postoperatively, routine beta2-transferrin assays show low sensitivity. They should not be used in these settings. The clinical course of patients with occult CSF leaks indicated possibility of an uneventful follow-up.

Hydrogen Leak Detection Sensor Database

NASA Technical Reports Server (NTRS)

Baker, Barton D.

2010-01-01

This slide presentation reviews the characteristics of the Hydrogen Sensor database. The database is the result of NASA's continuing interest in and improvement of its ability to detect and assess gas leaks in space applications. The database specifics and a snapshot of an entry in the database are reviewed. Attempts were made to determine the applicability of each of the 65 sensors for ground and/or vehicle use.

EIGHTH INTERIM STATUS REPORT: MODEL 9975 PCV O-RING FIXTURE LONG-TERM LEAK PERFORMANCE

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

Daugherty, W. L.

2013-09-03

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. Seventy tests using mock-ups of 9975 Primary Containment Vessels (PCVs) were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determine if they meet the criterion of leak-tightness defined in ANSI standard N14.5-97. Fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. High temperature aging continues for 23more » GLT O-ring fixtures at 200 – 270 ºF. Room temperature leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The remaining GLT O-ring fixtures aging at 300 ºF have been retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 61 - 85 months, which is still bounding to O-ring temperatures during storage in KArea Complex (KAC). Based on expectations that the fixtures aging at 200 ºF will remain leaktight for a significant period yet to come, 2 additional fixtures began aging in 2011 at an intermediate temperature of 270 ºF, with hopes that they may reach a failure condition before the 200 ºF fixtures. High temperature aging continues for 6 GLT-S O-ring fixtures at 200 – 300 ºF. Room temperature leak test failures have been experienced in all 8 of the GLT-S O-ring fixtures aging at 350 and 400 ºF. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 - 300 ºF for 41 - 45 months. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

Real-time electronic monitoring of a pitted and leaking gas gathering pipeline

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

Asperger, R.G.; Hewitt, P.G.

1986-08-01

Hydrogen patch, flush electrical resistance, and flush linear polarization proves wre used with flush coupons to monitor corrosion rates in a pitted and leaking sour gas gathering line. Four inhibitors were evaluated in stopping the leaks. Inhibitor residuals and the amount and ratio of water and condensate in the lines were measured at five locations along the line. The best inhibitor reduced reduced the pit-leak frequency by over a factor of 10. Inhibitor usage rate was optimized using the hydrogen patch current as a measure of the instantaneous corrosion rate. Improper pigging was identified as a cause of corrosion transients.more » This problem is discussed in relation to the pigging of pipelines in stratified flow where moving fluids are the carriers for continuously injected corrosion inhibitors.« less

Mitochondrial Proton Leak Plays a Critical Role in Pathogenesis of Cardiovascular Diseases.

PubMed

Cheng, Jiali; Nanayakkara, Gayani; Shao, Ying; Cueto, Ramon; Wang, Luqiao; Yang, William Y; Tian, Ye; Wang, Hong; Yang, Xiaofeng

2017-01-01

Mitochondrial proton leak is the principal mechanism that incompletely couples substrate oxygen to ATP generation. This chapter briefly addresses the recent progress made in understanding the role of proton leak in the pathogenesis of cardiovascular diseases. Majority of the proton conductance is mediated by uncoupling proteins (UCPs) located in the mitochondrial inner membrane. It is evident that the proton leak and reactive oxygen species (ROS) generated from electron transport chain (ETC) in mitochondria are linked to each other. Increased ROS production has been shown to induce proton conductance, and in return, increased proton conductance suppresses ROS production, suggesting the existence of a positive feedback loop that protects the biological systems from detrimental effects of augmented oxidative stress. There is mounting evidence attributing to proton leak and uncoupling proteins a crucial role in the pathogenesis of cardiovascular disease. We can surmise the role of "uncoupling" in cardiovascular disorders as follows; First, the magnitude of the proton leak and the mechanism involved in mediating the proton leak determine whether there is a protective effect against ischemia-reperfusion (IR) injury. Second, uncoupling by UCP2 preserves vascular function in diet-induced obese mice as well as in diabetes. Third, etiology determines whether the proton conductance is altered or not during hypertension. And fourth, proton leak regulates ATP synthesis-uncoupled mitochondrial ROS generation, which determines pathological activation of endothelial cells for recruitment of inflammatory cells. Continue effort in improving our understanding in the role of proton leak in the pathogenesis of cardiovascular and metabolic diseases would lead to identification of novel therapeutic targets for treatment.

Comparison of enterotomy leak pressure among fresh, cooled, and frozen-thawed porcine jejunal segments.

PubMed

Aeschlimann, Kimberly A; Mann, F A; Middleton, John R; Belter, Rebecca C

2018-05-01

OBJECTIVE To determine whether stored (cooled or frozen-thawed) jejunal segments can be used to obtain dependable leak pressure data after enterotomy closure. SAMPLE 36 jejunal segments from 3 juvenile pigs. PROCEDURES Jejunal segments were harvested from euthanized pigs and assigned to 1 of 3 treatment groups (n = 12 segments/group) as follows: fresh (used within 4 hours after collection), cooled (stored overnight at 5°C before use), and frozen-thawed (frozen at -12°C for 8 days and thawed at room temperature [23°C] for 1 hour before use). Jejunal segments were suspended and 2-cm enterotomy incisions were made on the antimesenteric border. Enterotomies were closed with a simple continuous suture pattern. Lactated Ringer solution was infused into each segment until failure at the suture line was detected. Leak pressure was measured by use of a digital transducer. RESULTS Mean ± SD leak pressure for fresh, cooled, and frozen-thawed segments was 68.3 ± 23.7 mm Hg, 55.3 ± 28.1 mm Hg, and 14.4 ± 14.8 mm Hg, respectively. Overall, there were no significant differences in mean leak pressure among pigs, but a significant difference in mean leak pressure was detected among treatment groups. Mean leak pressure was significantly lower for frozen-thawed segments than for fresh or cooled segments, but mean leak pressure did not differ significantly between fresh and cooled segments. CONCLUSIONS AND CLINICAL RELEVANCE Fresh porcine jejunal segments or segments cooled overnight may be used for determining intestinal leak pressure, but frozen-thawed segments should not be used.

Prolonged air leak following lobectomy can be predicted in lung cancer patients.

PubMed

Okada, Satoru; Shimada, Junichi; Kato, Daishiro; Tsunezuka, Hiroaki; Inoue, Masayoshi

2017-08-01

The purpose of this study was to identify the factors associated with prolonged air leak (PAL) following pulmonary lobectomy for lung cancer. The data of 146 patients who underwent pulmonary lobectomy for lung cancer between August 2010 and July 2015 were retrospectively reviewed. Air leaks were assessed daily by a visual evaluation and were categorized as follows: forced expiratory only (Grade 1), expiratory only (Grade 2), or continuous (Grade 3). Logistic regression analyses were performed to identify the predictors of PAL (>5 days). PAL occurred in 23 patients (16%). An air leak at rest (Grade ≥ 2) was detected on postoperative day (POD) 1 in 48% of the patients with PAL and 7% of the patients without PAL. A univariate analysis demonstrated that PAL was significantly associated with male sex, a smoking history of ≥ 40 pack years, a serum albumin level of ≤4.0 mg/dL, and an air leak on POD1 (Grade ≥ 2). A multivariate analysis demonstrated that a serum albumin level of ≤4.0 mg/dL (p = 0.027) and an air leak on POD1 (p = 0.006) were independent predictors of PAL. PAL occurred in 75% of the patients with these two risk factors. The preoperative serum albumin level and the presence of a visually evaluated air leak on POD1 may be useful indicators for the perioperative management of air leaks.

Autologous fibrin sealant reduces the incidence of prolonged air leak and duration of chest tube drainage after lung volume reduction surgery: a prospective randomized blinded study.

PubMed

Moser, C; Opitz, I; Zhai, W; Rousson, V; Russi, E W; Weder, W; Lardinois, D

2008-10-01

Prolonged air leak is reported in up to 50% of patients after lung volume reduction surgery. The effect of an autologous fibrin sealant on the intensity and duration of air leak and on the time to chest drain removal after lung volume reduction surgery was investigated in a randomized prospective clinical trial. Twenty-five patients underwent bilateral thoracoscopic lung volume reduction surgery. In each patient, an autologous fibrin sealant was applied along the staple lines on one side, whereas no additional measure was taken on the other side. Randomization of treatment was performed at the end of the resection on the first side. Air leak was assessed semiquantitatively by use of a severity score (0 = no leak; 4 = continuous severe leak) by two investigators blinded to the treatment. Mean value of the total severity scores for the first 48 hours postoperative was significantly lower in the treated group (4.7 +/- 7.7) than in the control group (16.0 +/- 10.1) (P < .001), independently of the length of the resection. Prolonged air leak and mean duration of drainage were also significantly reduced after application of the sealant (4.5% and 2.8 +/- 1.9 days versus 31.8% and 5.9 +/- 2.9 days) (P = .03 and P < .001). Autologous fibrin sealant for reinforcement of the staple lines after lung volume reduction surgery significantly reduces prolonged air leak and duration of chest tube drainage.

Does the type of pancreaticojejunostomy after Whipple alter the leak rate?

PubMed

Ball, Chad G; Howard, Thomas J

2010-01-01

Despite the overwhelming limitations that plague the literature surrounding the optimal method of reestablishing pancreatico-enteric continuity following a Whipple operation, it is clear that all successful techniques conform to sound surgical principles. These principles include a water-tight and tension-free anastomosis, preservation of adequate blood supply for both organs involved in the anastomosis, and minimal trauma to the pancreas gland. Although surgeon experience, gland texture, and pancreatic duct size are clearly the dominate risk factors from a long list of variables associated with pancreatic leaks following pancreatoduodenectomy, these are nonmodifiable covariates. Although the plethora of current literature cannot provide a single definitive technical solution for restoring pancreatico-enteric continuity, a small number of well-designed RCTs support the use of transanastomotic external stenting for high-risk pancreatic glands and an end-to-side invaginated pancreaticojejunostomy. The truth remains that an individual surgeon's mastery of a specific anastomotic technique, in conjunction with a large personal experience, is likely to be the best predictor of a low pancreas leak rate following pancreatoduodenectomy.

40 CFR 63.7331 - What are the installation, operation, and maintenance requirements for my monitors?

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air... baghouse applied to pushing emissions, you must install, operate, and maintain each bag leak detection...

40 CFR 63.9804 - What are my monitoring system installation, operation, and maintenance requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... pressure or induced air fabric filters, the bag leak detector must be installed downstream of the fabric... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

40 CFR 63.8450 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... bag leak detection system, you must meet the requirements in paragraphs (e)(1) through (11) of this...

40 CFR 63.8450 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... bag leak detection system, you must meet the requirements in paragraphs (e)(1) through (11) of this...

40 CFR 63.11527 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... an existing affected source, you may install, operate, and maintain a bag leak detection system for...

40 CFR 63.8450 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... bag leak detection system, you must meet the requirements in paragraphs (e)(1) through (11) of this...

40 CFR 63.8450 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... bag leak detection system, you must meet the requirements in paragraphs (e)(1) through (11) of this...

40 CFR 63.11527 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... an existing affected source, you may install, operate, and maintain a bag leak detection system for...

40 CFR 63.11527 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for... an existing affected source, you may install, operate, and maintain a bag leak detection system for...

40 CFR 63.7921 - How do I demonstrate initial compliance with the emissions limitations and work practice...

Code of Federal Regulations, 2011 CFR

2011-07-01

....7921 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Hazardous Air Pollutants: Site Remediation Equipment Leaks § 63.7921 How do I...

40 CFR 63.7921 - How do I demonstrate initial compliance with the emissions limitations and work practice...

Code of Federal Regulations, 2013 CFR

2013-07-01

....7921 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Hazardous Air Pollutants: Site Remediation Equipment Leaks § 63.7921 How do I...

40 CFR 63.7921 - How do I demonstrate initial compliance with the emissions limitations and work practice...

Code of Federal Regulations, 2010 CFR

2010-07-01

....7921 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Hazardous Air Pollutants: Site Remediation Equipment Leaks § 63.7921 How do I...

40 CFR 63.7921 - How do I demonstrate initial compliance with the emissions limitations and work practice...

Code of Federal Regulations, 2014 CFR

2014-07-01

....7921 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Hazardous Air Pollutants: Site Remediation Equipment Leaks § 63.7921 How do I...

40 CFR 63.7921 - How do I demonstrate initial compliance with the emissions limitations and work practice...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL... Standards for Hazardous Air Pollutants: Site Remediation Equipment Leaks § 63.7921 How do I demonstrate...

Neonatal mannequin comparison of the Upright self-inflating bag and snap-fit mask versus standard resuscitators and masks: leak, applied load and tidal volumes.

PubMed

Rafferty, Anthony Richard; Johnson, Lucy; Davis, Peter G; Dawson, Jennifer Anne; Thio, Marta; Owen, Louise S

2017-11-30

Neonatal mask ventilation is a difficult skill to acquire and maintain. Mask leak is common and can lead to ineffective ventilation. The aim of this study was to determine whether newly available neonatal self-inflating bags and masks could reduce mask leak without additional load being applied to the face. Forty operators delivered 1 min episodes of mask ventilation to a mannequin using the Laerdal Upright Resuscitator, a standard Laerdal infant resuscitator (Laerdal Medical) and a T-Piece Resuscitator (Neopuff), using both the Laerdal snap-fit face mask and the standard Laerdal size 0/1 face mask (equivalent sizes). Participants were asked to use pressure sufficient to achieve 'appropriate' chest rise. Leak, applied load, airway pressure and tidal volume were measured continuously. Participants were unaware that load was being recorded. There was no difference in mask leak between resuscitation devices. Leak was significantly lower when the snap-fit mask was used with all resuscitation devices, compared with the standard mask (14% vs 37% leak, P<0.01). The snap-fit mask was preferred by 83% of participants. The device-mask combinations had no significant effect on applied load. The Laerdal Upright Resuscitator resulted in similar leak to the other resuscitation devices studied, and did not exert additional load to the face and head. The snap-fit mask significantly reduced overall leak with all resuscitation devices and was the mask preferred by participants. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

40 CFR 63.8600 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... compartment or cell. (7) For negative pressure or induced air fabric filters, the bag leak detector must be... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for...

40 CFR 63.11163 - What are the standards and compliance requirements for new sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Primary... to a control device. (d) You must install, operate, and maintain a bag leak detection system on all...

40 CFR 63.1187 - What do I need to know about operations, maintenance, and monitoring plans?

Code of Federal Regulations, 2011 CFR

2011-07-01

... include: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

40 CFR 63.8600 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... compartment or cell. (7) For negative pressure or induced air fabric filters, the bag leak detector must be... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for...

40 CFR 63.1187 - What do I need to know about operations, maintenance, and monitoring plans?

Code of Federal Regulations, 2013 CFR

2013-07-01

... include: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

40 CFR 63.8600 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... compartment or cell. (7) For negative pressure or induced air fabric filters, the bag leak detector must be... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for...

40 CFR 63.8600 - What are my monitoring installation, operation, and maintenance requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... compartment or cell. (7) For negative pressure or induced air fabric filters, the bag leak detector must be... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for...

40 CFR 63.1187 - What do I need to know about operations, maintenance, and monitoring plans?

Code of Federal Regulations, 2012 CFR

2012-07-01

... include: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

40 CFR 63.1187 - What do I need to know about operations, maintenance, and monitoring plans?

Code of Federal Regulations, 2014 CFR

2014-07-01

... include: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

NSRD-10: Leak Path Factor Guidance Using MELCOR

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

Louie, David; Humphries, Larry L.

Estimates of the source term from a U.S. Department of Energy (DOE) nuclear facility requires that the analysts know how to apply the simulation tools used, such as the MELCOR code, particularly for a complicated facility that may include an air ventilation system and other active systems that can influence the environmental pathway of the materials released. DOE has designated MELCOR 1.8.5, an unsupported version, as a DOE ToolBox code in its Central Registry, which includes a leak-path-factor guidance report written in 2004 that did not include experimental validation data. To continue to use this MELCOR version requires additional verificationmore » and validations, which may not be feasible from a project cost standpoint. Instead, the recent MELCOR should be used. Without any developer support and lack of experimental data validation, it is difficult to convince regulators that the calculated source term from the DOE facility is accurate and defensible. This research replaces the obsolete version in the 2004 DOE leak path factor guidance report by using MELCOR 2.1 (the latest version of MELCOR with continuing modeling development and user support) and by including applicable experimental data from the reactor safety arena and from applicable experimental data used in the DOE-HDBK-3010. This research provides best practice values used in MELCOR 2.1 specifically for the leak path determination. With these enhancements, the revised leak-path-guidance report should provide confidence to the DOE safety analyst who would be using MELCOR as a source-term determination tool for mitigated accident evaluations.« less

Validation of Test Methods for Air Leak Rate Verification of Spaceflight Hardware

NASA Technical Reports Server (NTRS)

Oravec, Heather Ann; Daniels, Christopher C.; Mather, Janice L.

2017-01-01

As deep space exploration continues to be the goal of NASAs human spaceflight program, verification of the performance of spaceflight hardware becomes increasingly critical. Suitable test methods for verifying the leak rate of sealing systems are identified in program qualification testing requirements. One acceptable method for verifying the air leak rate of gas pressure seals is the tracer gas leak detector method. In this method, a tracer gas (commonly helium) leaks past the test seal and is transported to the leak detector where the leak rate is quantified. To predict the air leak rate, a conversion factor of helium-to-air is applied depending on the magnitude of the helium flow rate. The conversion factor is based on either the molecular mass ratio or the ratio of the dynamic viscosities. The current work was aimed at validating this approach for permeation-level leak rates using a series of tests with a silicone elastomer O-ring. An established pressure decay method with constant differential pressure was used to evaluate both the air and helium leak rates of the O-ring under similar temperature and pressure conditions. The results from the pressure decay tests showed, for the elastomer O-ring, that neither the molecular flow nor the viscous flow helium-to-air conversion factors were applicable. Leak rate tests were also performed using nitrogen and argon as the test gas. Molecular mass and viscosity based helium-to-test gas conversion factors were applied, but did not correctly predict the measured leak rates of either gas. To further this study, the effect of pressure boundary conditions was investigated. Often, pressure decay leak rate tests are performed at a differential pressure of 101.3 kPa with atmospheric pressure on the downstream side of the test seal. In space applications, the differential pressure is similar, but with vacuum as the downstream pressure. The same O-ring was tested at four unique differential pressures ranging from 34.5 to 137.9 kPa. Up to six combinations of upstream and downstream pressures for each differential pressure were compared. For a given differential pressure, the various combinations of upstream and downstream dry air pressures did not significantly affect the leak rate. As expected, the leak rate of the O-ring increased with increasing differential pressure. The results suggested that the current leak test pressure conditions, used to verify spacecraft sealing systems with elastomer seals, produce accurate values even though the boundary conditions do not model the space application.

Incidence and management of anastomotic leakage following laparoscopic prostatectomy with implementation of a new anastomotic technique incorporating posterior bladder neck tailoring.

PubMed

Sukkarieh, T; Harmon, J; Penna, F; Parra, R

2007-01-01

In laparoscopic prostatectomies, vesicourethral anastomotic leaks may result in significant morbidity because of the chemical and metabolic derangements created by urine within the peritoneal cavity. To date, minimal data are available on this problem. Herein we present our experience with urine leaks after RALP. Over a period of 24 months, 135 men underwent RALP. Any drainage creatinine greater than two times the serum creatinine was considered as an anastomotic leak. According to our criteria, 20% of the first 110 patients developed an anastomotic leak. The patients were analyzed in two groups, those with and without leaks. In the two groups, there was no statistically significant difference in age, height, weight, prostate volume and pre-op hemoglobin. The patients with leaks did have higher rate of prior abdominal surgery (50 vs. 36%), higher average pre-operative PSA values (7.6 vs. 6.1), higher rates of multiple biopsies (27 vs. 17%) and a higher average BMI (29.6 vs. 27.8). Intraoperative differences included an average of 30 min longer operative time and 66 cm(3) higher average EBL in patients with leaks. The transfusion rate was higher in the leak group at 18 vs. 1% in the no leak group. Recovery tended to be longer in patients with leaks, with hospital stays of an average of 3.6 days longer. The most common indication for prolonged hospitalization was ileus, which 55% of patients with leaks developed. Management included placing the catheter on mild traction, continuous antibiotics and taking the drain-off suction with caution to monitor the signs of a worsening ileus. In the last 25 patients, we revised our anastomotic technique. We now include posterior tailoring of the bladder neck prior to the vesicourethral anastomosis when the bladder neck is enlarged. This facilitates a water-tight anastomosis. Using this technique, we have yet to see the anastomotic leak. In RALPs, anastomotic leaks can lead to ileus formation and longer hospital stays. These leaks are associated with a higher average blood loss and transfusion rate. Management should focus on prevention. Since we have incorporated posterior bladder neck tailoring with the anastomosis, the problem has been markedly reduced.

40 CFR 61.111 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Definitions. 61.111 Section 61.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive...

40 CFR 61.112 - Standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards. 61.112 Section 61.112 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Equipment Leaks (Fugitive...

40 CFR 63.1350 - Monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... For a negative-pressure or induced-air fabric filter, the bag leak detector must be installed... Section 63.1350 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission...

Apparatus and Method for Low-Temperature Training of Shape Memory Alloys

NASA Technical Reports Server (NTRS)

Swanger, A. M.; Fesmire, J. E.; Trigwell, S.; Gibson, T. L.; Williams, M. K.; Benafan, O.

2015-01-01

An apparatus and method for the low-temperature thermo-mechanical training of shape memory alloys (SMA) has been developed. The experimental SMA materials are being evaluated as prototypes for applicability in novel thermal management systems for future cryogenic applications. Alloys providing two-way actuation at cryogenic temperatures are the chief target. The mechanical training regimen was focused on the controlled movement of rectangular strips, with S-bend configurations, at temperatures as low as 30 K. The custom holding fixture included temperature sensors and a low heat-leak linear actuator with a magnetic coupling. The fixture was mounted to a Gifford-McMahon cryocooler providing up to 25 W of cooling power at 20 K and housed within a custom vacuum chamber. Operations included both training cycles and verification of shape memory movement. The system design and operation are discussed. Results of the training for select prototype alloys are presented.

Apparatus and method for low-temperature training of shape memory alloys

NASA Astrophysics Data System (ADS)

Swanger, A. M.; Fesmire, J. E.; Trigwell, S.; Gibson, T. L.; Williams, M. K.; Benafan, O.

2015-12-01

An apparatus and method for the low-temperature thermo-mechanical training of shape memory alloys (SMA) has been developed. The experimental SMA materials are being evaluated as prototypes for applicability in novel thermal management systems for future cryogenic applications. Alloys providing two-way actuation at cryogenic temperatures are the chief target. The mechanical training regimen was focused on the controlled movement of rectangular strips, with S-bend configurations, at temperatures as low as 30 K. The custom holding fixture included temperature sensors and a low heat-leak linear actuator with a magnetic coupling. The fixture was mounted to a Gifford-McMahon cryocooler providing up to 25 W of cooling power at 20 K and housed within a custom vacuum chamber. Operations included both training cycles and verification of shape memory movement. The system design and operation are discussed. Results of the training for select prototype alloys are presented.

Localization of CO2 Leakage from a Circular Hole on a Flat-Surface Structure Using a Circular Acoustic Emission Sensor Array

PubMed Central

Cui, Xiwang; Yan, Yong; Guo, Miao; Han, Xiaojuan; Hu, Yonghui

2016-01-01

Leak localization is essential for the safety and maintenance of storage vessels. This study proposes a novel circular acoustic emission sensor array to realize the continuous CO2 leak localization from a circular hole on the surface of a large storage vessel in a carbon capture and storage system. Advantages of the proposed array are analyzed and compared with the common sparse arrays. Experiments were carried out on a laboratory-scale stainless steel plate and leak signals were obtained from a circular hole in the center of this flat-surface structure. In order to reduce the influence of the ambient noise and dispersion of the acoustic wave on the localization accuracy, ensemble empirical mode decomposition is deployed to extract the useful leak signal. The time differences between the signals from the adjacent sensors in the array are calculated through correlation signal processing before estimating the corresponding distance differences between the sensors. A hyperbolic positioning algorithm is used to identify the location of the circular leak hole. Results show that the circular sensor array has very good directivity toward the circular leak hole. Furthermore, an optimized method is proposed by changing the position of the circular sensor array on the flat-surface structure or adding another circular sensor array to identify the direction of the circular leak hole. Experiential results obtained on a 100 cm × 100 cm stainless steel plate demonstrate that the full-scale error in the leak localization is within 0.6%. PMID:27869765

Optimal control of fuel overpressure in a polymer electrolyte membrane fuel cell with hydrogen transfer leak during load change

NASA Astrophysics Data System (ADS)

Ebadighajari, Alireza; DeVaal, Jake; Golnaraghi, Farid

2017-02-01

Formation of membrane pinholes is a common defect in fuel cells, inflicting more cost and making less durable cells. This work focuses on mitigating this issue, and offers a continuous online treatment instead of attempting to dynamically model the hydrogen transfer leak rate. This is achieved by controlling the differential pressure between the anode and cathode compartments at the inlet side of the fuel cell stack, known as the fuel overpressure. The model predictive control approach is used to attain the objectives in a Ballard 9-cell Mk1100 polymer electrolyte membrane fuel cell (PEMFC) with inclusion of hydrogen transfer leak. Furthermore, the pneumatic modeling technique is used to model the entire anode side of a fuel cell station. The hydrogen transfer leak is embedded in the model in a novel way, and is considered as a disturbance during the controller design. Experimental results for different sizes of hydrogen transfer leaks are provided to show the benefits of fuel overpressure control system in alleviating the effects of membrane pinholes, which in turn increases membrane longevity, and reduces hydrogen emissions in the eventual presence of transfer leaks. Moreover, the model predictive controller provides an optimal control input while satisfying the problem constraints.

Laser-based sensor for a coolant leak detection in a nuclear reactor

NASA Astrophysics Data System (ADS)

Kim, T.-S.; Park, H.; Ko, K.; Lim, G.; Cha, Y.-H.; Han, J.; Jeong, D.-Y.

2010-08-01

Currently, the nuclear industry needs strongly a reliable detection system to continuously monitor a coolant leak during a normal operation of reactors for the ensurance of nuclear safety. In this work, we propose a new device for the coolant leak detection based on tunable diode laser spectroscopy (TDLS) by using a compact diode laser. For the feasibility experiment, we established an experimental setup consisted of a near-IR diode laser with a wavelength of about 1392 nm, a home-made multi-pass cell and a sample injection system. The feasibility test was performed for the detection of the heavy water (D2O) leaks which can happen in a pressurized heavy water reactor (PWHR). As a result, the device based on the TDLS is shown to be operated successfully in detecting a HDO molecule, which is generated from the leaked heavy water by an isotope exchange reaction between D2O and H2O. Additionally, it is suggested that the performance of the new device, such as sensitivity and stability, can be improved by adapting a cavity enhanced absorption spectroscopy and a compact DFB diode laser. We presume that this laser-based leak detector has several advantages over the conventional techniques currently employed in the nuclear power plant, such as radiation monitoring, humidity monitoring and FT-IR spectroscopy.

40 CFR 63.7887 - What are the general standards I must meet for my affected equipment leak sources?

Code of Federal Regulations, 2014 CFR

2014-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation General Standards § 63.7887 What are the general standards I must meet for my...

40 CFR 63.7887 - What are the general standards I must meet for my affected equipment leak sources?

Code of Federal Regulations, 2010 CFR

2010-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation General Standards § 63.7887 What are the general standards I must meet for my...

40 CFR 63.7887 - What are the general standards I must meet for my affected equipment leak sources?

Code of Federal Regulations, 2012 CFR

2012-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation General Standards § 63.7887 What are the general standards I must meet for my...

40 CFR 63.7887 - What are the general standards I must meet for my affected equipment leak sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation General Standards § 63.7887 What are the general standards I must meet for my...

40 CFR 63.7887 - What are the general standards I must meet for my affected equipment leak sources?

Code of Federal Regulations, 2011 CFR

2011-07-01

... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS... Pollutants: Site Remediation General Standards § 63.7887 What are the general standards I must meet for my...

40 CFR 63.11457 - What are the recordkeeping requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Glass Manufacturing Area... calibration and maintenance records. (7) For each bag leak detection system, the records specified in...

40 CFR 63.11457 - What are the recordkeeping requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Glass Manufacturing Area... calibration and maintenance records. (7) For each bag leak detection system, the records specified in...

40 CFR 63.11457 - What are the recordkeeping requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Glass Manufacturing Area... calibration and maintenance records. (7) For each bag leak detection system, the records specified in...

40 CFR 63.11457 - What are the recordkeeping requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Glass Manufacturing Area... calibration and maintenance records. (7) For each bag leak detection system, the records specified in...

Influence of intraoperative hypotension on leaks after sleeve gastrectomy.

PubMed

Nienhuijs, Simon W; Kaymak, Uzay; Korsten, Erik; Buise, Marc P

2016-01-01

Leak after a sleeve gastrectomy (SG) is a severe complication. Risk factors, such as regional ischemia, increased intraluminal pressure, technical failure of the stapling device, and surgeon error, have been reported. It was hypothesized that intraoperative hypotension is another risk factor for leak, similar to that reported for colorectal surgery. Tertiary teaching hospital in The Netherlands. Results of a 7-year cohort of primary SGs were reviewed in relation to multiple intraoperative blood pressure measurements. The thresholds for the mean pressure were 40 to 70 mm Hg and for the systolic pressure 70 to 100 mm Hg. Only continuous episodes of 15 and 20 minutes were included. Twenty-four leaks were identified in a cohort of 1041 primary SGs. Episodes of systolic blood pressure<100 mm Hg for 15 min (P = .027) and 20 minutes (P = .008) were significantly related to a staple line leak. An episode of mean blood pressure<70 mm Hg for 20 min was significantly related to leak (P = .014). Episodes with lower thresholds of pressure occurred less frequently and revealed no significant differences. Other identified risk factors were smoking (P = .019), fast-track recovery program (P = .006), use of a tri-stapler (P = .004), and duration of surgery (P = .000). In a multivariate analysis, only intraoperative systolic pressure<100 mm Hg for 20 minutes remained significant (odds ratio, 2.45; P = .012). Intraoperative hypotension may contribute independently to a leak after SG. Copyright © 2016 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

40 CFR 63.1002 - Compliance assessment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Compliance assessment. 63.1002 Section 63.1002 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... Emission Standards for Equipment Leaks-Control Level 1 § 63.1002 Compliance assessment. (a) General...

40 CFR 61.242-1 - Standards: General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards: General. 61.242-1 Section 61.242-1 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Equipment Leaks...

40 CFR 65.100 - Applicability.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Applicability. 65.100 Section 65.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.100 Applicability. (a) Equipment subject to this subpart. The...

The role of ICP monitoring in patients with persistent cerebrospinal fluid leak following spinal surgery: a case series.

PubMed

Craven, Claudia; Toma, Ahmed K; Khan, Akbar A; Watkins, Laurence D

2016-09-01

Cerebrospinal fluid (CSF) leak following spinal surgery is a relatively common surgical complication. A disturbance in the underlying CSF dynamics could be the causative factor in a small group of patients with refractory CSF leaks that require multiple surgical repairs and prolonged hospital admission. A retrospective case series of patients with persistent post spinal surgery CSF leak referred to the hydrocephalus service for continuous intracranial pressure (ICP) monitoring. Patients' notes were reviewed for medical history, ICP data, radiological data, and subsequent management and outcome. Five patients (two males/three females, mean age, 35.4 years) were referred for ICP monitoring over a 12-month period. These patients had prolonged CSF leak despite multiple repair attempts 252 ± 454 days (mean ± SD). On ICP monitoring, all five patients had abnormal results, with the mean ICP 8.95 ± 4.41 mmHg. Four had abnormal pulse amplitudes, mean 6.15 mmHg ± 1.22 mmHg. All five patients underwent an intervention. Three patients underwent insertion of ventriculoperitoneal (VP) shunts. One patient had venous sinus stent insertion and one patient underwent medical management with acetazolamide. All five of the patients' CSF leak resolved post intervention. The mean time to resolution of CSF leak post intervention was 10.8  ± 12.9 days. Abnormal cerebrospinal fluid dynamics could be the underlying factor in patients with a persistent and treatment-refractory CSF leak post spinal surgery. Treatments aimed at lowering ICP may be beneficial in this group of patients. Whether abnormal pressure and dynamics represent a pre-existing abnormality or is induced by spinal surgery should be a subject of further study.

Placement of a covered polyester stent prevents complications from a colorectal anastomotic leak and supports healing: randomized controlled trial in a large animal model.

PubMed

Tsereteli, Zurab; Sporn, Emanuel; Geiger, Timothy M; Cleveland, Dava; Frazier, Shellaine; Rawlings, Arthur; Bachman, Sharon L; Miedema, Brent W; Thaler, Klaus

2008-11-01

Anastomotic leaks after colorectal operation continue to be a significant cause of morbidity. A covered endoluminal stent could seal a leak and eliminate the need for diversion. The aim of this study was to test the efficacy of a temporary covered stent to prevent leak related complications. Sixteen adult pigs (80-120 lbs) underwent open transection of the rectosigmoid followed by anastomosis with a circular stapler. Eight animals (study group) underwent endoscopic placement of a 21-mm covered polyester stent. Eight control group animals were left without stents. In all animals, a 2-cm leak was created along the anterior portion of the anastomosis. The animals were killed after 2 weeks and evaluated for abdominal infection, fistulae, and adhesions. The anastomosis was excised and the following parameters were assessed by a pathologist blinded to treatment: mucosal interruption (mm), inflammatory response, collagen type I and III, granulation, and fibrosis (grade 0-4). Stents were spontaneously expelled between postoperative days 6 and 9. At necropsy, none of the animals in the study group had leak related complications, whereas in the control group, 5 (63%) developed intraabdominal infection (4 abscesses, 1 fistula) at the anastomosis (P = .002). Dense adhesions to the anastomosis were found in 7 (88%) control animals. On histology, anastomotic sites in the study group had significantly less mucosal interruption and granulation. Two pigs in the study group died on postoperative day 7, one due to evisceration and one from bladder necrosis. The mortality result is not different from controls (P = .47), both events seem to be unrelated to stent placement. Temporary placement of a covered polyester stent across a colorectal anastomosis prevents leak-related complications and supports the healing of anastomotic leaks.

40 CFR 65.121-65.139 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false [Reserved] 65.121-65.139 Section 65.121-65.139 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks §§ 65.121-65.139 [Reserved] ...

40 CFR 65.101 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Definitions. 65.101 Section 65.101 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.101 Definitions. All terms used in this subpart shall have the...

40 CFR 63.11552 - What are my monitoring requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

... filter for air leaks, torn or broken bags or filter media, or any other condition that may cause an...? 63.11552 Section 63.11552 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

40 CFR 63.11552 - What are my monitoring requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

... filter for air leaks, torn or broken bags or filter media, or any other condition that may cause an...? 63.11552 Section 63.11552 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

40 CFR 63.11552 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... filter for air leaks, torn or broken bags or filter media, or any other condition that may cause an...? 63.11552 Section 63.11552 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

40 CFR 63.11552 - What are my monitoring requirements?

Code of Federal Regulations, 2012 CFR

2012-07-01

... filter for air leaks, torn or broken bags or filter media, or any other condition that may cause an...? 63.11552 Section 63.11552 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

Eleventh interim status report: Model 9975 O-Ring fixture long-term leak performance

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

Daugherty, W.

2016-08-01

A series of experiments to monitor the aging performance of Viton® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially and have been tested periodically to determinemore » if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF.« less

Tenth interim status report: Model 9975 O-ring fixture long-term leak performance

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

Daugherty, W. L.

2015-08-26

A series of experiments to monitor the aging performance of Viton ® GLT O-rings used in the Model 9975 package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperatures. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups were assembled and heated to temperatures ranging from 200 to 450 °F. They were leak-tested initially and have been tested periodically tomore » determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, fourteen additional tests were initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 °F.« less

Heated, humidified high-flow nasal cannula therapy: yet another way to deliver continuous positive airway pressure?

PubMed

Kubicka, Zuzanna J; Limauro, Joseph; Darnall, Robert A

2008-01-01

The goal was to estimate the level of delivered continuous positive airway pressure by measuring oral cavity pressure with the mouth closed in infants of various weights and ages treated with heated, humidified high-flow nasal cannula at flow rates of 1-5 L/minute. We hypothesized that clinically relevant levels of continuous positive airway pressure would not be achieved if a nasal leak is maintained. After performing bench measurements and demonstrating that oral cavity pressure closely approximated levels of traditionally applied nasal continuous positive airway pressure, we successfully measured oral cavity pressure during heated, humidified, high-flow nasal cannula treatment in 27 infants. Small (outer diameter: 0.2 cm) cannulae were used for all infants, and flow rates were left as ordered by providers. Bench measurements showed that, for any given leak size, there was a nearly linear relationship between flow rate and pressure. The highest pressure achieved was 4.5 cmH2O (flow rate: 8 L/minute; leak: 3 mm). In our study infants (postmenstrual age: 29.1-44.7 weeks; weight: 835-3735 g; flow rate: 1-5 L/minute), no pressure was generated with the mouth open at any flow rate. With the mouth closed, the oral cavity pressure was related to both flow rate and weight. For infants of < or = 1500 g, there was a linear relationship between flow rate and oral cavity pressure. Oral cavity pressure can estimate the level of continuous positive airway pressure. Continuous positive airway pressure generated with heated, humidified, high-flow nasal cannula treatment depends on the flow rate and weight. Only in the smallest infants with the highest flow rates, with the mouth fully closed, can clinically significant but unpredictable levels of continuous positive airway pressure be achieved. We conclude that heated, humidified high-flow nasal cannula should not be used as a replacement for delivering continuous positive airway pressure.

40 CFR 146.67 - Operating requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... serving as a water supply, place a notice in a newspaper of general circulation. (2) The Director may... 146.67 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS (CONTINUED... steps to determine the presence or absence of a leak; and (3) Notify the Director within 24 hours after...

40 CFR 60.57c - Monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... pressure or induced air fabric filters, the bag leak detector shall be installed downstream of the fabric... 60.57c Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... owner or operator of an affected facility using an air pollution control device other than a dry...

40 CFR 60.57c - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... pressure or induced air fabric filters, the bag leak detector shall be installed downstream of the fabric... 60.57c Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... owner or operator of an affected facility using an air pollution control device other than a dry...

40 CFR 63.9600 - What are my operation and maintenance requirements?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) through (vi) of this section. (i) Inspecting the baghouse for air leaks, torn or broken bags or filter... requirements? 63.9600 Section 63.9600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

40 CFR 63.9600 - What are my operation and maintenance requirements?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) through (vi) of this section. (i) Inspecting the baghouse for air leaks, torn or broken bags or filter... requirements? 63.9600 Section 63.9600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES...

Hanford Double-Shell Tank AY-102 Radioactive Waste Leak Investigation Update - 15302

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

Washenfelder, D. J.; Johnson, J. M.

2014-12-22

Tank AY-102 was the first of 28 double-shell radioactive waste storage tanks constructed at the U. S. Department of Energy’s Hanford Site, near Richland, WA. The tank was completed in 1970, and entered service in 1971. In August, 2012, an accumulation of material was discovered at two sites on the floor of the annulus that separates the primary tank from the secondary liner. The material was sampled and determined to originate from the primary tank. This paper summarizes the changes in leak behavior that have occurred during the past two years, inspections to determine the capability of the secondary linermore » to continue safely containing the leakage, and the initial results of testing to determine the leak mechanism.« less

Demonstration of the BNL Continuous Dual Trap Analyzer to Detect Perfluorocarbon Tracers for the Tag, Track and Location Program

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

Heiser,J.H.; Adams, J.; Dietz, R..

2008-10-07

The Tag, Track and Location System (TTL) Program is investigating methods of tracking an asset using perfluorocarbon tracers (PFT). The success of any TTL method requires sound detection/location instrumentation. Tracer Detection Technologies Corp (TDT), through a contract with the Office of Naval Research (ONR), is investigating different detection systems. The detections systems generally fall into two categories; proximity detectors and standoff detectors. Proximity detectors, as the name implies, need to be in close proximity (e.g., meter to 10's of meters) to the PFT source. Standoff detection searches for the PFT from a greater distance away from the source (e.g., 100'smore » of meters to kilometers). Gas Chromatographs (GC) are generally considered a proximity detection systems, but in the case of PFTs should be considered for both proximity and standoff detection with the caveat that in standoff use the GC needs to be somewhere in the PFT plume, i.e., generally downwind of the source. With a properly sized PFT source, the right GC can afford fairly large standoff (distance from the source) distances; 100's of meters to kilometers downwind. Brookhaven National Laboratory (BNL) has such a GC system and offered to demonstrate the CDTA for TTL as a no cost addition to the TDTTTL project, of which BNL was a participant. BNL is a leading authority on the sampling, collection, release and detection of PFTs. In addition, the BNL team has extensive background in atmospheric dispersion, the application of PFTs to such studies and the development of applications utilizing PFTs such as building infiltration measurements, control room integrity determination, leak location and environmental investigations. This experience and expertise is essential in developing any PFT application were dispersion, dilution and overcoming environmental conditions and interferences are integral to success. BNL has developed sophisticated gas chromatography methods and instruments that allow detection of up to seven PFTs at part per quadrillion levels (1015) with sample times as short as 60 seconds. The Continuous Dual-Trap Analyzer (CDTA) was developed for leak hunting applications and can continuously sample the air for PFTs without interruption. Sample time can be as short as 60 seconds. The CDTA has been extensively used in the commercial sector to detect PFTs that have been introduced to leaking buried dielectric fluid-filled cables or leaking subsurface gas lines. The PFTs travel through the cable or pipe until they reach the leak site. PFTs then escape into the surrounding soil and permeate/diffuse to the surface where they can be detected with the CDTA. Typically a cable is tagged with ppm levels of PFTs resulting in ppt to ppq concentrations in the air at the leak site. The CDTA is proven to be rugged, reliable and has a proven track record of successful leak location. The application of the CDTA to PFT detection for TTL is identical to application for leak detection. The CDTA operator has a general idea, with a few miles of roadway, where the leak is located, but no specific knowledge of the location (it can be any where along the road). The CDTA is mounted in a Chevy Astro Van and is dispatched to the field. In the field the van is driven at nominally 15 mph along the road. The CDTA continuously samples the air outside the van (via a 1/4-inch plastic sample tube stuck out a side window) until a positive detection occurs. The van then covers the road section where the detection occurred at a slightly slower pace to pin-point the area where the leak is and to direct soil probe samples. The soil probe samples take soil gas samples every 10 yards or so and the samples are analyzed on the CDTA. The leak can be located to within a few feet in 95% of the cases. To date the CDTA has been successful in every leak hunt performed by BNL. One interesting case was a leak hunt that resulted in repeated negative detections. The confidence in the CDTA forced the utility to recheck its 'plumbing' which lead to the discovery that a valve was turned that shouldn't have been so that gas was being diverted rather than leaking (the pressure drop was due to this diversion of the gas to another line). For TTL application, a tagged item or person is known to be in a general area and can be located by detecting the PFT emanating from the tagging source. The CDTA can be deployed in the area and by sampling in a grid fashion (starting on the downwind side of the area of interest) can easily find even very small sources. The CDTA is a perfect match for this application and the leak hunt use basically a simulation of Track and Locate. No other PFT detection technology has the detection sensitivity, proven track record and ruggedness of the CDTA. For these reasons, BNL offered to demonstrate the CDTA for TTL as a no cost addition to the TTL lidar demonstration project. This report details the demonstration scenario and results.« less

40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.111 Standards...

40 CFR 63.1033 - Open-ended valves or lines standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Open-ended valves or lines standards... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1033 Open-ended...

40 CFR 63.1014 - Open-ended valves or lines standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Open-ended valves or lines standards... PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 1 § 63.1014 Open-ended valves or...

Bubble CPAP versus CPAP with variable flow in newborns with respiratory distress: a randomized controlled trial.

PubMed

Yagui, Ana Cristina Zanon; Vale, Luciana Assis Pires Andrade; Haddad, Luciana Branco; Prado, Cristiane; Rossi, Felipe Souza; Deutsch, Alice D Agostini; Rebello, Celso Moura

2011-01-01

To evaluate the efficacy and safety of nasal continuous positive airway pressure (NCPAP) using devices with variable flow or bubble continuous positive airway pressure (CPAP) regarding CPAP failure, presence of air leaks, total CPAP and oxygen time, and length of intensive care unit and hospital stay in neonates with moderate respiratory distress (RD) and birth weight (BW) ≥ 1,500 g. Forty newborns requiring NCPAP were randomized into two study groups: variable flow group (VF) and continuous flow group (CF). The study was conducted between October 2008 and April 2010. Demographic data, CPAP failure, presence of air leaks, and total CPAP and oxygen time were recorded. Categorical outcomes were tested using the chi-square test or the Fisher's exact test. Continuous variables were analyzed using the Mann-Whitney test. The level of significance was set at p < 0.05. There were no differences between the groups with regard to demographic data, CPAP failure (21.1 and 20.0% for VF and CF, respectively; p = 1.000), air leak syndrome (10.5 and 5.0%, respectively; p = 0.605), total CPAP time (median: 22.0 h, interquartile range [IQR]: 8.00-31.00 h and median: 22.0 h, IQR: 6.00-32.00 h, respectively; p = 0.822), and total oxygen time (median: 24.00 h, IQR: 7.00-85.00 h and median: 21.00 h, IQR: 9.50-66.75 h, respectively; p = 0.779). In newborns with BW ≥ 1,500 g and moderate RD, the use of continuous flow NCPAP showed the same benefits as the use of variable flow NCPAP.

40 CFR 63.7830 - What are my monitoring requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Integrated Iron and Steel... leaks. (viii) Inspect fans for wear, material buildup, and corrosion through quarterly visual...

Repairing pipes on the fly

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

NONE

1997-04-01

When piping develops leaks, the natural instinct is to shut the process down, purge the lines and call in maintenance crews to make the repairs. There is, however, an alternative: on-the-fly repairs. Through the use of specialized tools, equipment and technicians, shut-off valves can be installed and leaks repaired without interrupting production. The split sleeve offers one of the simpler approaches to on-the-fly repairs. Two half cylinders with inside diameter slightly larger than the outside diameter slightly larger than the outside diameter of the pipe to be repaired are slipped over the latter some distance form the leak and looselymore » bolted together. The cylinder is then slid over the leaking area and the bolts tightened. Gaskets inside the half cylinders provide the needed seal between the pipe and the cylinder. Installing a shut-off valve in an operating pipeline requires much more specialized equipment and skills than does repairing a leak with a split sleeve. A device available from International Piping Services Co. allows a trained crew to isolate a section of pipe, drill out the isolated portion, install a blocking valve and then remove the isolation system--all while continuing to operate the pipeline at temperatures to 700 F and pressures to 700 psi. But Herb Porter, CEO of Ipsco, cautions that unlike the repairing leaks with a split sleeve, installing a blocking valve on-the-fly always demands the services of a highly trained crew.« less

Spontaneous spinal cerebrospinal fluid leak as a cause of coma after craniotomy for clipping of an unruptured intracranial aneurysm.

PubMed

Schievink, Wouter I; Palestrant, David; Maya, M Marcel; Rappard, George

2009-03-01

Spontaneous spinal CSF leaks are best known as a cause of orthostatic headache, but may also be the cause of coma. The authors encountered a unique case of a spontaneous spinal CSF leak causing coma 2 days after craniotomy for clipping of an unruptured aneurysm. This 44-year-old woman with autosomal dominant polycystic kidney disease underwent an uneventful craniotomy for an incidental anterior choroidal artery aneurysm. No intraoperative spinal CSF drainage was used. Two days after surgery the patient became comatose with a left oculomotor nerve palsy. Computed tomography scanning revealed a right extraceberal hematoma and loss of gray-white matter differentiation. The hematoma was evacuated and a diagnosis of hemodialysis disequilibrium syndrome was made. Continuous hemodialysis and hyperosmolar therapy were instituted without any improvement. The CT scans were then reinterpreted as showing sagging of the brain, and the patient was placed in the Trendelenburg position which resulted in prompt improvement in her level of consciousness. A CT myelogram demonstrated an upper thoracic CSF leak that eventually required surgical correction. The patient made a complete neurological recovery. Neurological deterioration after craniotomy may be caused by brain sagging caused by a spontaneous spinal CSF leak, similar to intracranial hypotension due to intraoperative lumbar CSF drainage.

Ubiquitous Low-Cost Functionalized Multi-Walled Carbon Nanotube Sensors for Distributed Methane Leak Detection

DOE PAGES

Humayun, Md Tanim; Divan, Ralu; Stan, Liliana; ...

2016-06-16

This paper presents a highly sensitive, energy efficient and low-cost distributed methane (CH 4) sensor system (DMSS) for continuous monitoring, detection, and localization of CH 4 leaks in natural gas infrastructure, such as transmission and distribution pipelines, wells, and production pads. The CH 4 sensing element, a key component of the DMSS, consists of a metal oxide nanocrystal (MONC) functionalized multi-walled carbon nanotube (MWCNT) mesh which, in comparison to existing literature, shows stronger relative resistance change while interacting with lower parts per million (ppm) concentration of CH 4. A Gaussian plume triangulation algorithm has been developed for the DMSS. Givenmore » a geometric model of the surrounding environment the algorithm can precisely detect and localize a CH 4 leak as well as estimate its mass emission rate. A UV-based surface recovery technique making the sensor recover 10 times faster than the reported ones is presented for the DMSS. In conclusion, a control algorithm based on the UV-accelerated recovery is developed which facilitates faster leak detection.« less

An improved PCA method with application to boiler leak detection.

PubMed

Sun, Xi; Marquez, Horacio J; Chen, Tongwen; Riaz, Muhammad

2005-07-01

Principal component analysis (PCA) is a popular fault detection technique. It has been widely used in process industries, especially in the chemical industry. In industrial applications, achieving a sensitive system capable of detecting incipient faults, which maintains the false alarm rate to a minimum, is a crucial issue. Although a lot of research has been focused on these issues for PCA-based fault detection and diagnosis methods, sensitivity of the fault detection scheme versus false alarm rate continues to be an important issue. In this paper, an improved PCA method is proposed to address this problem. In this method, a new data preprocessing scheme and a new fault detection scheme designed for Hotelling's T2 as well as the squared prediction error are developed. A dynamic PCA model is also developed for boiler leak detection. This new method is applied to boiler water/steam leak detection with real data from Syncrude Canada's utility plant in Fort McMurray, Canada. Our results demonstrate that the proposed method can effectively reduce false alarm rate, provide effective and correct leak alarms, and give early warning to operators.

40 CFR 63.1206 - When and how must you comply with the standards and operating requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants from Hazardous... time under § 63.6(i) or § 63.1213, except: (1) Cement kilns are exempt from the bag leak detection...

40 CFR 63.1206 - When and how must you comply with the standards and operating requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES National Emission Standards for Hazardous Air Pollutants from Hazardous... time under § 63.6(i) or § 63.1213, except: (1) Cement kilns are exempt from the bag leak detection...

Nasal versus oronasal continuous positive airway pressure masks for obstructive sleep apnea: a pilot investigation of pressure requirement, residual disease, and leak.

PubMed

Bakker, Jessie P; Neill, Alister M; Campbell, Angela J

2012-09-01

This single-blinded, randomized, controlled pilot study aimed to investigate whether there is a difference between nasal and oronasal masks in therapeutic continuous positive airway pressure (CPAP) requirement, residual disease, or leak when treating obstructive sleep apnea (OSA) and if differences were related to measures of upper airway size. Patients with severe OSA currently using CPAP at ≥4 h/night with a nasal mask were examined (including Mallampati scale, incisal relationship, and mandibular protrusion) and then randomized to receive auto-positive airway pressure (PAP) or fixed CPAP at a manually titrated pressure for 1 week each at home, with immediate crossover. Within each week, a nasal mask and two oronasal masks were to be used for two or three nights each in random order. Data were downloaded from the device. Twelve patients completed the trial (mean ± SD AHI 59.8 ± 28.6 events/h; CPAP 11.1 ± 3.2 cmH(2)O; BMI 37.7 ± 5.0 kg/m(2)). During auto-PAP, the median 95th percentile pressure delivered with all masks was within 0.5 cmH(2)O (p > 0.05). During CPAP, median residual AHI was 0.61 (IQR = 1.18) for the nasal mask, 1.70 (IQR = 4.04) for oronasal mask 1, and 2.48 (IQR = 3.74) for oronasal mask 2 (p = 0.03). The 95th percentile leak was lowest with the nasal mask during both CPAP and auto-PAP (both p < 0.01). Differences in pressure or residual disease were not related to measures of upper airway shape or body habitus. In obese OSA patients changing from a nasal to oronasal mask increased leak and residual AHI but did not affect the therapeutic pressure requirement. The findings of the current study highlight mask leak as the major difficulty in the use of oronasal masks.

40 CFR 264.310 - Closure and post-closure care.

Code of Federal Regulations, 2010 CFR

2010-07-01

... settling, subsidence, erosion, or other events; (2) Continue to operate the leachate collection and removal system until leachate is no longer detected; (3) Maintain and monitor the leak detection system in...

40 CFR 264.310 - Closure and post-closure care.

Code of Federal Regulations, 2012 CFR

2012-07-01

... settling, subsidence, erosion, or other events; (2) Continue to operate the leachate collection and removal system until leachate is no longer detected; (3) Maintain and monitor the leak detection system in...

40 CFR 264.310 - Closure and post-closure care.

Code of Federal Regulations, 2013 CFR

2013-07-01

... settling, subsidence, erosion, or other events; (2) Continue to operate the leachate collection and removal system until leachate is no longer detected; (3) Maintain and monitor the leak detection system in...

40 CFR 264.310 - Closure and post-closure care.

Code of Federal Regulations, 2014 CFR

2014-07-01

... settling, subsidence, erosion, or other events; (2) Continue to operate the leachate collection and removal system until leachate is no longer detected; (3) Maintain and monitor the leak detection system in...

40 CFR 264.310 - Closure and post-closure care.

Code of Federal Regulations, 2011 CFR

2011-07-01

... settling, subsidence, erosion, or other events; (2) Continue to operate the leachate collection and removal system until leachate is no longer detected; (3) Maintain and monitor the leak detection system in...

40 CFR 63.8630 - What notifications must I submit and when?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Clay Ceramics Manufacturing...) For each APCD that includes a fabric filter, if a bag leak detection system is used, analysis and...

Michael Jackson, Bin Laden and I: functions of positive and negative, public and private flashbulb memories.

PubMed

Demiray, Burcu; Freund, Alexandra M

2015-01-01

This study examined the perceived psychosocial functions of flashbulb memories: It compared positive and negative public flashbulb memories (positive: Bin Laden's death, negative: Michael Jackson's death) with private ones (positive: pregnancy, negative: death of a loved one). A sample of n = 389 young and n = 176 middle-aged adults answered canonical category questions used to identify flashbulb memories and rated the personal significance, the psychological temporal distance, and the functions of each memory (i.e., self-continuity, social-boding, directive functions). Hierarchical regressions showed that, in general, private memories were rated more functional than public memories. Positive and negative private memories were comparable in self-continuity and directionality, but the positive private memory more strongly served social functions. In line with the positivity bias in autobiographical memory, positive flashbulb memories felt psychologically closer than negative ones. Finally, middle-aged adults rated their memories as less functional regarding self-continuity and social-bonding than young adults. Results are discussed regarding the tripartite model of autobiographical memory functions.

John F. Kennedy Space Center's Chemochromic Hypergol Sensors

NASA Technical Reports Server (NTRS)

Nichols, James D.

2012-01-01

The National Aeronautics and Space Administration (NASA) seeks partne rs interested in the commercial application of the Chemochromic Hyper gol Sensors technology. NASA's Kennedy Space Center (KSC) is soliciti ng licensees for this innovative technology. The Chemochromic Hypergo l Sensors technology consists of chemochromic pigments incorporated i nto various matrices (e.g., tapes, sheets, injection molded parts, fi bers). When placed near strategic locations such as piping and contai ner valves, seams, and joints, these sensors provide an instantaneous , distinct color change from yellow to black indicating the presence of hypergols at the leak location. The chemochromic pigments can be incorporated into fibers used to make fabrics for personal protective equipment as well as into badge holders for use as a point leak detector. These affordable, easily replaceable sensors provide the capabil ity to visually monitor leak-prone locations and personnel working i n those areas on a continuous basis for the presence of dangerous hyp ergols.

Measurement of the Neutron Lifetime with Ultra-cold Neutrons Stored in a Magneto-gravitational Trap

NASA Astrophysics Data System (ADS)

Ezhov, V. F.; Andreev, A. Z.; Ban, G.; Bazarov, B. A.; Geltenbort, P.; Glushkov, A. G.; Knyazkov, V. A.; Kovrizhnykh, N. A.; Krygin, G. B.; Naviliat-Cuncic, O.; Ryabov, V. L.

2018-05-01

We report a measurement of the neutron lifetime using ultra-cold neutrons stored in a magneto-gravitational trap made of permanent magnets. Neutrons surviving in the trap after fixed storage times have been counted and the trap losses have continuously been monitored during storage by detecting neutrons leaking from the trap. The value of the neutron lifetime resulting from this measurement is τ n = (878.3 ± 1.6stat ± 1.0syst) s. A unique feature of this experiment is the monitoring of leaking neutrons providing a robust control of the main systematic loss.

iss053e238931

NASA Image and Video Library

2017-11-22

iss053e238931 (Nov. 22, 2017) --- Flight Engineer Alexander Misurkin from Roscosmos works with the JPL Electronic Nose (ENose) experiment in the Zvezda service module. ENose is a full-time, continuously operating event monitor designed to detect air contamination from spills and leaks in the crew habitat of the International Space Station. It fills the long-standing gap between onboard alarms and complex analytical instruments. ENose provides rapid, early identification and quantification of atmospheric changes caused by chemical species to which it has been trained. ENose can also be used to monitor cleanup processes after a leak or a spill.

49 CFR 229.45 - General condition.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements General Requirements..., oil, water, steam, and other leaks and accumulations of oil on electrical equipment that create a...

Functions of autobiographical memory in Taiwanese and American emerging adults.

PubMed

Liao, Hsiao-Wen; Bluck, Susan; Alea, Nicole; Cheng, Ching-Ling

2016-01-01

The study addresses cultural and person-level factors contributing to emerging adult's use of memory to serve adaptive functions. The focus is on three functions: self-continuity, social-bonding and directing-behaviour. Taiwanese (N = 85, 52 women) and American (N = 95, 51 women) emerging adults completed the Thinking about Life Experiences scale, and measures of trait personality, self-concept clarity and future time perspective. Findings show that individuals from both cultures use memory to serve these three functions, but Taiwanese individuals use memory more frequently than Americans to maintain self-continuity. Culture also interacted with person-level factors: in Taiwan, but not America, memory is more frequently used to create self-continuity in individuals high in conscientiousness. Across cultures, having lower self-concept clarity was related to greater use of memory to create self-continuity. Findings are discussed in terms of how memory serves functions in context and specific aspects of the Taiwanese and American cultural context that may predict the functional use of memory in emerging adulthood.

Aberrant wound-healing response in mitomycin C-treated leaking blebs: a histopathologic study.

PubMed

Elner, Victor M; Newman-Casey, Paula Anne; Patil, A Jayaprakash; Flint, Andrew; Biswas, Jyotirmay; Moroi, Sayoko E; Pushparaj, Vaijayanthi; Edward, Deepak P

2009-08-01

To characterize histopathologic features of leaking mitomycin C-treated blebs and aberrant wound healing that may lead to persistent conjunctival thinning and leakage. Forty mitomycin C-treated filtering blebs excised for persistent leaks from 40 patients were examined histopathologically using hematoxylin-eosin, periodic acid-Schiff, Masson trichrome, and Alcian blue histochemical stains. Ninety percent of the leaking blebs contained epithelial-stromal domes with areas of acellular stroma covered by attenuated epithelium. Seventy-five percent of the blebs demonstrated varying degrees of fibrovascular repair growing from the bleb margin, either beneath or interdigitating with the acellular zone. A novel observation in 65% of specimens was Alcian blue-positive myxoid stroma at the interface between the fibrovascular proliferation and the epithelial-stromal dome. The association between the presence of fibrovascular proliferation and Alcian blue-staining myxoid stroma was significant by Fisher exact test (P = .002). A desirable filtration bleb requires a sufficient reparative fibrovascular response to maintain an epithelial-stromal barrier to prevent leakage. Fibroblasts must lay down a continuous collagen-rich fibrous layer, rather than merely myxoid stroma, beneath the conjunctival epithelium to promote bleb stability. Surgical techniques and postsurgical care should aim to attain this desired outcome.

Bath and Shower Diverter Notice of Intent

EPA Pesticide Factsheets

An often-overlooked source of wasted water, many bath and shower diverters continuously leak a small amount of water from the tub spout while they are engaged, and water is being diverted from the bathtub to the showerhead.

Secret information reconciliation based on punctured low-density parity-check codes for continuous-variable quantum key distribution

NASA Astrophysics Data System (ADS)

Jiang, Xue-Qin; Huang, Peng; Huang, Duan; Lin, Dakai; Zeng, Guihua

2017-02-01

Achieving information theoretic security with practical complexity is of great interest to continuous-variable quantum key distribution in the postprocessing procedure. In this paper, we propose a reconciliation scheme based on the punctured low-density parity-check (LDPC) codes. Compared to the well-known multidimensional reconciliation scheme, the present scheme has lower time complexity. Especially when the chosen punctured LDPC code achieves the Shannon capacity, the proposed reconciliation scheme can remove the information that has been leaked to an eavesdropper in the quantum transmission phase. Therefore, there is no information leaked to the eavesdropper after the reconciliation stage. This indicates that the privacy amplification algorithm of the postprocessing procedure is no more needed after the reconciliation process. These features lead to a higher secret key rate, optimal performance, and availability for the involved quantum key distribution scheme.

40 CFR 63.2480 - What requirements must I meet for equipment leaks?

Code of Federal Regulations, 2013 CFR

2013-07-01

... connectors at your affected source. (5) For pumps in light liquid service in an MCPU that has no continuous... connectors in gas/vapor and light liquid service at an existing source, you may elect to comply with the... in light liquid service in an MCPU that has no continuous process vents and is part of an existing...

40 CFR 63.2480 - What requirements must I meet for equipment leaks?

Code of Federal Regulations, 2014 CFR

2014-07-01

... connectors at your affected source. (5) For pumps in light liquid service in an MCPU that has no continuous... connectors in gas/vapor and light liquid service at an existing source, you may elect to comply with the... in light liquid service in an MCPU that has no continuous process vents and is part of an existing...

40 CFR 63.2480 - What requirements must I meet for equipment leaks?

Code of Federal Regulations, 2012 CFR

2012-07-01

... connectors at your affected source. (5) For pumps in light liquid service in an MCPU that has no continuous... connectors in gas/vapor and light liquid service at an existing source, you may elect to comply with the... in light liquid service in an MCPU that has no continuous process vents and is part of an existing...

40 CFR 63.2480 - What requirements must I meet for equipment leaks?

Code of Federal Regulations, 2011 CFR

2011-07-01

... affected source. (5) For pumps in light liquid service in an MCPU that has no continuous process vents and.../vapor and light liquid service at an existing source, you may elect to comply with the requirements in... light liquid service in an MCPU that has no continuous process vents and is part of an existing source...

40 CFR 60.105a - Monitoring of emissions and operations for fluid catalytic cracking units (FCCU) and fluid coking...

Code of Federal Regulations, 2012 CFR

2012-07-01

... for air leaks, torn or broken bags or filter media, or any other condition that may cause an increase... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF... nozzles must conduct a daily check of the air or water pressure to the spray nozzles and record the...

Pneumostasis of experimental air leaks with a new photopolymerized synthetic tissue sealant.

PubMed

Ranger, W R; Halpin, D; Sawhney, A S; Lyman, M; Locicero, J

1997-09-01

Air leak is a major contributor to increased length of stay and postoperative morbidity following pulmonary surgery. The effectiveness of a new photopolymerized synthetic hydrogel (FocalSeal, Focal, Inc., Lexington, MA) as a sealant for pulmonary air leaks was determined in 10 mongrel dogs (20-35 kg). The animals were anesthetized and underwent left-sided anterolateral thoracotomy with amputation of a 2 x 3-cm segment of the lung apex. Hemostasis was achieved and terminal bronchial openings of 1.5 to 3 mm with vigorous air leaks were identified. After successful injury, the dogs were randomly assigned to sealant (n = 5) or control (n = 5) groups. In treated animals, the sealant was applied by brushing the solution to the cut parenchymal surface and solidified while briefly interrupting ventilation (40-60 seconds) using visible illumination (450-550 nm) from a xenon light source. Controls received no sealant. A single chest tube was maintained at the injury site with a continuous negative pressure of 20 cm of water. All dogs were extubated and allowed to breathe spontaneously under sedation for 24 hours. Chest radiographs were taken postsurgery and presacrifice. All control animals (n = 5) showed persistent vigorous air leak for the duration of the 24-hour observation period. All treated air leaks resolved immediately, and four of five remained sealed throughout the observation period. One leak reappeared after 17 hours due to inadequate sealant thickness over a 3-mm terminal bronchus. Gross evaluation of the treatment group at the end of 24 hours demonstrated intact sealant well adherent to the parenchyma. No evidence of atelectasis or excessive edema was seen, and no sealant-related complications or toxic effects were noted. Radiologically, lungs were fully inflated. Histologic evaluation at 24 hours revealed no evidence of a strong cellular response to the synthetic sealant, and no fibrosis or adhesions were seen, the onset of the healing process was favorable, indicating good biocompatability. In conclusion, this material was found to be an effective means for sealing bronchial and parenchymal air leaks in this model and warrants clinical evaluation.

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

Daugherty, W.; Mcwilliams, A.; Skidmore, E.

The 9975 Type B shipping package is used within the DOE complex for shipping special nuclear materials. This package is re-certified annually in accordance with Safety Analysis Report requirements. The package is also used at the Savannah River Site as part of the long-term storage configuration of special nuclear materials. As such, the packages do not undergo annual recertification during storage, with uncertainty as to how long some of the package components will meet their functional requirements in the storage environment. The packages are currently approved for up to 15 years storage, and work continues to provide a technical basismore » to extend that period. This paper describes efforts by the Savannah River National Laboratory (SRNL) to extend the service life estimate of Viton® GLT and GLT-S fluoroelastomer O-rings used in the 9975 shipping package. O-rings of both compositions are undergoing accelerated aging at elevated temperature, and are periodically tested for compression stress relaxation (CSR) behavior and leak performance. The CSR behavior of O-rings was evaluated at temperatures from 79 °C to 177 °C. These collective data were used to develop predictive models for extrapolation of CSR behavior to relevant service temperatures (< 75 °C). O-rings were also aged in Primary Containment Vessel (PCV) fixtures at temperatures ranging from 79 °C to 232 °C. The fixtures are helium leak tested periodically to determine if they remain leak-tight. The PCV fixture tests demonstrate that the 9975 O-rings will remain leak-tight at temperatures up to 149 °C for 3 years or more, and no leak failures have been observed with up to 8 years aging at 93 °C. Significantly longer periods of leak-tight service are expected at the lower temperatures actually experienced in the storage environment. The predictive model developed from the CSR data conservatively indicates a service life of more than 20 years at the bounding temperature of 75 °C. Although the relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance to date.« less

Evaluation of a new chest tube removal protocol using digital air leak monitoring after lobectomy: a prospective randomised trial.

PubMed

Brunelli, Alessandro; Salati, Michele; Refai, Majed; Di Nunzio, Luca; Xiumé, Francesco; Sabbatini, Armando

2010-01-01

The objective of this randomised trial was to assess the effectiveness of a new fast-track chest tube removal protocol taking advantage of digital monitoring of air leak compared to a traditional protocol using visual and subjective assessment of air leak (bubbles). One hundred and sixty-six patients submitted to pulmonary lobectomy for lung cancer were randomised in two groups with different chest tube removal protocols: (1) in the new protocol, chest tube was removed based on digitally recorded measurements of air leak flow; (2) in the traditional protocol, the chest tube removal was based on an instantaneous assessment of air leak during daily rounds. The two groups were compared in terms of chest tube duration, hospital stay and costs. The two groups were well matched for several preoperative and operative variables. Compared to the traditional protocol, the new digital recording protocol showed mean reductions in chest tube duration (p=0.0007), hospital stay (p=0.007) of 0.9 day, and a mean cost saving of euro 476 per patient (p=0.008). In the new chest tube removal protocol, 51% of patients had their chest tube removed by the second postoperative day versus only 12% of those in the traditional protocol. The application of a chest tube removal protocol using a digital drainage unit featuring a continuous recording of air leak was safe and cost effective. Although future studies are warranted to confirm these results in other settings, the use of this new protocol is now routinely applied in our practice. Copyright 2009 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.

From Brown-Peterson to continual distractor via operation span: A SIMPLE account of complex span.

PubMed

Neath, Ian; VanWormer, Lisa A; Bireta, Tamra J; Surprenant, Aimée M

2014-09-01

Three memory tasks-Brown-Peterson, complex span, and continual distractor-all alternate presentation of a to-be-remembered item and a distractor activity, but each task is associated with a different memory system, short-term memory, working memory, and long-term memory, respectively. SIMPLE, a relative local distinctiveness model, has previously been fit to data from both the Brown-Peterson and continual distractor tasks; here we use the same version of the model to fit data from a complex span task. Despite the many differences between the tasks, including unpredictable list length, SIMPLE fit the data well. Because SIMPLE posits a single memory system, these results constitute yet another demonstration that performance on tasks originally thought to tap different memory systems can be explained without invoking multiple memory systems.

Continuous integration and quality control for scientific software

NASA Astrophysics Data System (ADS)

Neidhardt, A.; Ettl, M.; Brisken, W.; Dassing, R.

2013-08-01

Modern software has to be stable, portable, fast and reliable. This is going to be also more and more important for scientific software. But this requires a sophisticated way to inspect, check and evaluate the quality of source code with a suitable, automated infrastructure. A centralized server with a software repository and a version control system is one essential part, to manage the code basis and to control the different development versions. While each project can be compiled separately, the whole code basis can also be compiled with one central “Makefile”. This is used to create automated, nightly builds. Additionally all sources are inspected automatically with static code analysis and inspection tools, which check well-none error situations, memory and resource leaks, performance issues, or style issues. In combination with an automatic documentation generator it is possible to create the developer documentation directly from the code and the inline comments. All reports and generated information are presented as HTML page on a Web server. Because this environment increased the stability and quality of the software of the Geodetic Observatory Wettzell tremendously, it is now also available for scientific communities. One regular customer is already the developer group of the DiFX software correlator project.

Evaluation of continuity detail for precast prestressed girders : tech summary.

DOT National Transportation Integrated Search

2011-08-01

Building multi-simple span bridges using precast prestressed concrete girders is an easy construction. However, the existence of : expansion joints often leads to a host of problems in their vicinity due to drainage leaks. Furthermore, debris accumul...

Leak localization and quantification with a small unmanned aerial system

NASA Astrophysics Data System (ADS)

Golston, L.; Zondlo, M. A.; Frish, M. B.; Aubut, N. F.; Yang, S.; Talbot, R. W.

2017-12-01

Methane emissions from oil and gas facilities are a recognized source of greenhouse gas emissions, requiring cost-effective and reliable monitoring systems to support leak detection and repair programs. We describe a set of methods for locating and quantifying natural gas leaks using a small unmanned aerial system (sUAS) equipped with a path-integrated methane sensor along with ground-based wind measurements. The algorithms are developed as part of a system for continuous well pad scale (100 m2 area) monitoring, supported by a series of over 200 methane release trials covering multiple release locations and flow rates. Test measurements include data obtained on a rotating boom platform as well as flight tests on a sUAS. The system is found throughout the trials to reliably distinguish between cases with and without a methane release down to 6 scfh (0.032 g/s). Among several methods evaluated for horizontal localization, the location corresponding to the maximum integrated methane reading have performed best with a median error of ± 1 m if two or more flights are averaged, or ± 1.2 m for individual flights. Additionally, a method of rotating the data around the estimated leak location is developed, with the leak magnitude calculated as the average crosswind integrated flux in the region near the source location. Validation of these methods will be presented, including blind test results. Sources of error, including GPS uncertainty, meteorological variables, and flight pattern coverage, will be discussed.

Headaches caused by decreased intracranial pressure: diagnosis and management.

PubMed

Mokri, Bahram

2003-06-01

More patients with spontaneous intracranial hypotension are now being diagnosed, and it is realized that most cases result from spontaneous cerebrospinal fluid leaks. A broader clinical and imaging spectrum of the disorder is recognized. This paper reviews new insights into the variability of clinical manifestations, imaging features, etiological factors, anatomy of leaks, and implications of these in patient management. Spontaneous intracranial hypotension should not be equated with post-lumbar puncture headaches. In a substantial minority of patients, headaches are not orthostatic and may mimic other types of headache. Additional diverse neurological manifestations may dominate the clinical picture and patients may occasionally have no headache at all. Reports on unusual presentations of the disorder continue to appear in the literature. Furthermore, additional imaging features of cerebrospinal fluid leaks are recognized. High-flow and slow-flow leaks may present diagnostic challenges, and require modification of diagnostic studies aimed at locating the site of the leak. Stigmata of connective tissue abnormality, especially abnormalities of fibrillin and elastin, are seen in a notable minority of patients, pointing to weakness of the dural sac as one of the etiological factors. After treatment of spontaneous intracranial hypotension, surgically or by epidural blood patch, a rebound and self-limiting intracranial hypertension may sometimes develop. In the past decade, interest in spontaneous intracranial hypotension has been rekindled, with a substantial growth of knowledge on various aspects of the disorder. We are in the learning phase, and new information will probably appear in the future, with notable diagnostic and therapeutic implications.

New Continuous Monitoring Technologies for Vapor Intrusion, Remediation and Site Assessment: Benefits of Time Series Data

DTIC Science & Technology

2011-03-31

00-00-2011 4. TITLE AND SUBTITLE New Continuous Monitoring Technologies for Vapor Intrusion, Remediation and Site Assessment . Benefits of Time...Std Z39-18 Dr Peter Morris, Geoff Hewitt New Continuous Monitoring Technologies for Vapor Intrusion, Remediation and Site Assessment . Benefits of...but which poses a greater risk ? V O C p p m Acetone Industrial facility with VOC Leak Site characterisation and Real time monitoring of Remediation

KSC-2009-3840

NASA Image and Video Library

2009-06-24

CAPE CANAVERAL, Fla. – On Launch Pad 39A at NASA's Kennedy Space Center in Florida, work continues on removing the Ground Umbilical Carrier Plate, or GUCP, on space shuttle Endeavour's external fuel tank. A hydrogen leak at the location during tanking for the STS-127 mission caused the launch attempts to be scrubbed on June 13 and June 17. The GUCP will be examined to determine the cause of the hydrogen leak and repaired. The GUCP is the overboard vent to the pad and the flame stack where the vented hydrogen is burned off. Endeavour's next launch attempt is targeted for July 11 at 7:39 p.m. EDT. Photo credit: NASA/Jack Pfaller

Recollection is a continuous process: Evidence from plurality memory receiver operating characteristics.

PubMed

Slotnick, Scott D; Jeye, Brittany M; Dodson, Chad S

2016-01-01

Is recollection a continuous/graded process or a threshold/all-or-none process? Receiver operating characteristic (ROC) analysis can answer this question as the continuous model and the threshold model predict curved and linear recollection ROCs, respectively. As memory for plurality, an item's previous singular or plural form, is assumed to rely on recollection, the nature of recollection can be investigated by evaluating plurality memory ROCs. The present study consisted of four experiments. During encoding, words (singular or plural) or objects (single/singular or duplicate/plural) were presented. During retrieval, old items with the same plurality or different plurality were presented. For each item, participants made a confidence rating ranging from "very sure old", which was correct for same plurality items, to "very sure new", which was correct for different plurality items. Each plurality memory ROC was the proportion of same versus different plurality items classified as "old" (i.e., hits versus false alarms). Chi-squared analysis revealed that all of the plurality memory ROCs were adequately fit by the continuous unequal variance model, whereas none of the ROCs were adequately fit by the two-high threshold model. These plurality memory ROC results indicate recollection is a continuous process, which complements previous source memory and associative memory ROC findings.

FY2017 status report: Model 9975 O-ring fixture long-term leak performance

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

Daugherty, W. L.

A series of experiments to monitor the aging performance of Viton® GLT and GLT-S O-rings used in the Model 9975 shipping package has been ongoing since 2004 at the Savannah River National Laboratory. One approach has been to periodically evaluate the leak performance of O-rings being aged in mock-up 9975 Primary Containment Vessels (PCVs) at elevated temperature. Other methods such as compression-stress relaxation (CSR) tests and field surveillance are also on-going to evaluate O-ring behavior. Seventy tests using PCV mock-ups with GLT O-rings were assembled and heated to temperatures ranging from 200 to 450 ºF. They were leak-tested initially andmore » have been tested periodically to determine if they continue to meet the leak-tightness criterion defined in ANSI standard N14.5-97. Due to material substitution, a smaller test matrix with fourteen additional tests was initiated in 2008 with GLT-S O-rings heated to temperatures ranging from 200 to 400 ºF. Leak test failures have been experienced in all of the GLT O-ring fixtures aging at 350 ºF and higher temperatures, and in 8 fixtures aging at 300 ºF. The 300 °F GLT O-ring fixtures failed after 2.8 to 5.7 years at temperature. The remaining GLT O-ring fixtures aging at 300 ºF were retired from testing following more than 5 years at temperature without failure. No failures have yet been observed in GLT O-ring fixtures aging at 200 ºF for 9 to 10.5 years, or in GLT O-ring fixtures aging at 270 ºF for 5.7 years. These aging temperatures bound O-ring temperatures anticipated during normal storage in K-Area Complex (KAC). Leak test failures have been experienced in all of the GLT-S O-ring fixtures aging at 300 ºF and above. No failures have yet been observed in GLT-S O-ring fixtures aging at 200 and 250 ºF for 6.9 to 7.5 years. Data from the O-ring fixtures are generally consistent with results from compression stress relaxation testing, and provide confidence in the predictive models based on those results. However, uncertainty still exists in extrapolating these elevated temperature results to the lower temperatures of interest for normal storage in KAC. Measurement of compression set in O-rings removed from failed fixtures, compared to that from KAC surveillance O-rings, indicates margin remains for O-rings still in service. Aging and periodic leak testing will continue for the remaining PCV fixtures.« less

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Closed vent systems and control devices; or emissions routed to a fuel gas system or process. 65.115 Section 65.115 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONSOLIDATED FEDERAL AIR RULE Equipment Leaks § 65.115 Standards:...

Quantifying, Assessing, and Mitigating Methane Emissions from Super-emitters in the Oil and Gas Supply Chain

NASA Astrophysics Data System (ADS)

Lyon, David Richard

Methane emissions from the oil and gas (O&G) supply chain reduce potential climate benefits of natural gas as a replacement for other fossil fuels that emit more carbon dioxide per energy produced. O&G facilities have skewed emission rate distributions with a small fraction of sites contributing the majority of emissions. Knowledge of the identity and cause of these high emission facilities, referred to as super-emitters or fat-tail sources, is critical for reducing supply chain emissions. This dissertation addresses the quantification of super-emitter emissions, assessment of their prevalence and relationship to site characteristics, and mitigation with continuous leak detection systems. Chapter 1 summarizes the state of the knowledge of O&G methane emissions. Chapter 2 constructs a spatially-resolved emission inventory to estimate total and O&G methane emissions in the Barnett Shale as part of a coordinated research campaign using multiple top-down and bottom-up methods to quantify emissions. The emission inventory accounts for super-emitters with two-phase Monte Carlo simulations that combine site measurements collected with two approaches: unbiased sampling and targeted sampling of super-emitters. More comprehensive activity data and the inclusion of super-emitters, which account for 19% of O&G emissions, produces a emission inventory that is not statistically different than top-down regional emission estimates. Chapter 3 describes a helicopter-based survey of over 8,000 well pads in seven basins with infrared optical gas imaging to assess high emission sources. Four percent of sites are observed to have high emissions with over 90% of observed sources from tanks. The occurrence of high emissions is weakly correlated to site parameters and the best statistical model explains only 14% of variance, which demonstrates that the occurrence of super-emitters is primarily stochastic. Chapter 4 presents a Gaussian dispersion model for optimizing the placement of continuous leak detection systems at three example well pads. The model demonstrates that large leaks can be detected quickly with first generation systems. Continuous leak detection can be used in the near future to cost-effectively mitigate methane emissions from O&G super-emitters.

40 CFR 63.1038 - Recordkeeping requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Recordkeeping requirements. 63.1038 Section 63.1038 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1038 Recordkeeping...

40 CFR 63.1383 - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... manufacturing facility must prepare for each glass-melting furnace, rotary spin manufacturing line, and flame... glass-melting furnace, the owner or operator shall install, calibrate, maintain, and continuously... monitors. (v) A triboelectric bag leak detection system shall be installed, operated, adjusted, and...

Pseudomaster equation for the no-count process in a continuous photodetection

NASA Technical Reports Server (NTRS)

Lee, Ching-Tsung

1994-01-01

The detection of cavity radiation with the detector placed outside the cavity is studied. Each leaked photon has a certain probability of propagating away without being detected. It is viewed as a continuous quantum measurement in which the density matrix is continuously revised according to the readout of the detector. The concept of pseudomaster equation for the no-count process is introduced; its solution leads to the discovery of the superoperator for the same process. It has the potential to become the key equation for continuous measurement process.

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.

Aberrant Wound-Healing Response in Mitomycin C-Treated Leaking Blebs: A Histopathologic Study

PubMed Central

Elner, Victor M.; Newman-Casey, Paula Anne; Patil, A. Jayaprakash; Flint, Andrew; Biswas, Jyotirmay; Moroi, Sayoko E.; Pushparaj, Vaijayanthi; Edward, Deepak P.

2014-01-01

Objective To characterize histopathologic features of leaking mitomycin-C-treated blebs and aberrant wound healing that may lead to persistent conjunctival thinning and leakage. Methods Forty mitomycin C-treated filtering blebs excised for persistent leaks from 40 patients were examined histopathologically using hematoxylin-eosin, periodic acid-Schiff, Masson trichrome, and Alcian blue histochemical stains. Results Ninety percent of the leaking blebs contained epithelial-stromal domes with areas of acellular stroma covered by attenuated epithelium. Seventy-five percent of the blebs demonstrated varying degrees of fibrovascular repair growing from the bleb margin, either beneath or interdigitating with the acellular zone. A novel observation in 65% of specimens was Alcian blue-positive myxoid stroma at the interface between the fibrovascular proliferation and the epithelial-stromal dome. The association between the presence of fibrovascular proliferation and Alcian-blue staining myxoid stroma was significant by Fisher exact test (P=0.002). Conclusions A desirable filtration bleb requires a sufficient reparative fibrovascular response to maintain an epithelial-stromal barrier in order to prevent leakage. Fibroblasts must lay down a continuous collagen-rich fibrous layer, rather than merely myxoid stroma, beneath the conjunctival epithelium to promote bleb stability. Surgical techniques and postsurgical care should aim to attain this desired outcome. PMID:19667341

40 CFR 745.83 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... with none of the air leaking past it. Interim controls means a set of measures designed to temporarily... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED... disposable cleaning cloths with the card, whether post-renovation cleaning has been properly completed...

40 CFR 745.83 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... with none of the air leaking past it. Interim controls means a set of measures designed to temporarily... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED... disposable cleaning cloths with the card, whether post-renovation cleaning has been properly completed...

Circumferentially oversewn inverted stapled anastomosis.

PubMed

Karam, Charbel; Lord, Sally; Gett, Rohan; Meagher, Alan P

2018-04-01

Leak rates of over 5% following anastomoses between the ileum and colon continue to be reported in large series and are associated with substantial morbidity and with mortality rates of 10-20%. In 1994, we began performing circumferentially oversewn inverted stapled anastomoses in patients undergoing ileo-colic anastomoses or ileostomy closure. It has become increasingly apparent that this method is associated with a low risk of leakage, which we should report. The anastomotic technique described was used in all patients undergoing ileo-colic anastomosis or closure of ileostomy by surgeon 1 (1994-2015) and in all ileo-colic anastomoses by surgeon 2 (2007-2015). All patients had a widely patent anastomosis constructed by two firings of a linear cutting stapler, as previously described. Additionally, the entire staple line was carefully oversewn with interrupted, inverting 4/0 polydioxanone sutures. Anastomotic leak was defined as a patient requiring re-operation or radiological drainage. One thousand and twelve patients underwent ileo-colic anastomosis and 685 patients underwent closure of ileostomy by surgeon 1, and 165 patients underwent ileo-colic anastomosis by surgeon 2. None of the 1862 patients required re-operation or radiological drainage for a leak (event rate 0%, 95% confidence interval 0-0.2%). However, there were three possible contained leaks treated successfully conservatively. The time taken to perform the actual anastomosis was measured in the last 30 ileo-colic resections. The median time was 42 min. While this method may well be too slow to gain widespread adoption, we hope this report encourages increased research into finding techniques with similar low leak rates. © 2016 Royal Australasian College of Surgeons.

International Space Station Node 1 is moved for leak test

NASA Technical Reports Server (NTRS)

1998-01-01

Node 1, the first element for the International Space Station, and attached Pressurized Mating Adapter-1 continue with prelaunch preparation activities at KSC's Space Station Processing Facility. Node 1 is a connecting passageway to the living and working areas of the space station. The node is being removed from the element rotation stand, or test stand, where it underwent an interim weight and center of gravity determination. (The final determination is planned to be performed prior to transporting Node 1 to the launch pad.) Now the node is being moved to the Shuttle payload transportation canister, where the doors will be closed for a two-week leak check. Node 1 is scheduled to fly on STS-88.

Feasibility of an on-line fission-gas-leak detection system

NASA Technical Reports Server (NTRS)

Lustig, P. H.

1973-01-01

Calculations were made to determine if a cladding failure could be detected in a 100-kW zirconium hydride reactor primary system by monitoring the highly radioactive NaK coolant for the presence of I-131. The system is to be completely sealed. A leak of 0.01 percent from a single fuel pin was postulated. The 0.364-MeV gamma of I-131 could be monitored on an almost continuous basis, while its presence could be varified by using a longer counting time for the 0.638-MeV gamma. A lithium-drifted germanium detector would eliminate radioactive corrosion product interference that could occur with a sodium iodide scintillation detector.

Sniffer used as portable hydrogen leak detector

NASA Technical Reports Server (NTRS)

Dayan, V. H.; Rommel, M. A.

1966-01-01

Sniffer type portable monitor detects hydrogen in air, oxygen, nitrogen, or helium. It indicates the presence of hydrogen in contact with activated palladium black by a change in color of a thermochromic paint, and indicates the quantity of hydrogen by a sensor probe and continuous readout.

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2012 CFR

2012-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2014 CFR

2014-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2013 CFR

2013-07-01

... section are met. (A) The zero (low-level), mid-level (if applicable), or high-level calibration drift... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 227.11 - Containerized wastes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 227.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.11... or leak on impact or shortly thereafter must meet the appropriate requirements of §§ 227.6, 227.7...

40 CFR 227.11 - Containerized wastes.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 227.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.11... or leak on impact or shortly thereafter must meet the appropriate requirements of §§ 227.6, 227.7...

40 CFR 227.11 - Containerized wastes.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 227.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.11... or leak on impact or shortly thereafter must meet the appropriate requirements of §§ 227.6, 227.7...

40 CFR 227.11 - Containerized wastes.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 227.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.11... or leak on impact or shortly thereafter must meet the appropriate requirements of §§ 227.6, 227.7...

40 CFR 227.11 - Containerized wastes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 227.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) OCEAN DUMPING CRITERIA FOR THE EVALUATION OF PERMIT APPLICATIONS FOR OCEAN DUMPING OF MATERIALS Environmental Impact § 227.11... or leak on impact or shortly thereafter must meet the appropriate requirements of §§ 227.6, 227.7...

Sptrace

NASA Technical Reports Server (NTRS)

Burleigh, Scott C.

2011-01-01

Sptrace is a general-purpose space utilization tracing system that is conceptually similar to the commercial Purify product used to detect leaks and other memory usage errors. It is designed to monitor space utilization in any sort of heap, i.e., a region of data storage on some device (nominally memory; possibly shared and possibly persistent) with a flat address space. This software can trace usage of shared and/or non-volatile storage in addition to private RAM (random access memory). Sptrace is implemented as a set of C function calls that are invoked from within the software that is being examined. The function calls fall into two broad classes: (1) functions that are embedded within the heap management software [e.g., JPL's SDR (Simple Data Recorder) and PSM (Personal Space Management) systems] to enable heap usage analysis by populating a virtual time-sequenced log of usage activity, and (2) reporting functions that are embedded within the application program whose behavior is suspect. For ease of use, these functions may be wrapped privately inside public functions offered by the heap management software. Sptrace can be used for VxWorks or RTEMS realtime systems as easily as for Linux or OS/X systems.

Pulmonary air leak associated with CPAP at term birth resuscitation.

PubMed

Hishikawa, Kenji; Goishi, Keiji; Fujiwara, Takeo; Kaneshige, Masao; Ito, Yushi; Sago, Haruhiko

2015-09-01

The Japan Resuscitation Council (JRC) Guidelines 2010 for neonatal resuscitation introduced continuous positive airway pressure (CPAP) in delivery room. The present study evaluated the effect of CPAP for pulmonary air leak at term birth. This retrospective single-centre study used the data of term neonates who were born without major congenital anomalies at our centre between 2008 and 2009, and between 2011 and 2012. Resuscitation according to the JRC Guidelines 2010. We examined the association between the JRC Guidelines 2010, CPAP by face mask and pulmonary air leak. A total of 5038 infants were analysed. The frequency of CPAP by face mask increased after the update of the JRC Guidelines in 2010 (1.7% vs 11.1%; p<0.001). Pulmonary air leak increased at early term (37 weeks: 1.0% vs 3.5%, p=0.02; 38 weeks: 0.7% vs 2.2%, p=0.02). While adjusting for confounders, the JRC Guidelines 2010 was associated with pulmonary air leak in early-term neonates (37 weeks: adjusted OR (aOR) 4.37; 95% CI 1.40 to 17.45; 38 weeks: aOR 2.80; 95% CI 1.04 to 8.91), but this association disappeared while adjusting for face mask CPAP additionally (37 weeks: aOR 1.90; 95% CI 0.47 to 8.71; 38 weeks: aOR 1.66; 95% CI 0.54 to 5.77). Following the update of the JRC guidelines on neonatal resuscitation, we observed an increased use of CPAP via face mask, which was associated with a higher prevalence of pulmonary air leak in early-term neonates in our centre. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Sampling connection systems standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 1 § 63.1013 Sampling connection... sampling connection system shall be equipped with a closed purge, closed loop, or closed vent system...

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Sampling connection systems standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1032 Sampling.... Each sampling connection system shall be equipped with a closed-purge, closed-loop, or closed vent...

Evidence that the Na+-K+ leak/pump ratio contributes to the difference in endurance between fast- and slow-twitch muscles.

PubMed

Clausen, T; Overgaard, K; Nielsen, O B

2004-02-01

Muscles containing predominantly fast-twitch (type II) fibres [ext. dig. longus (EDL)] show considerably lower contractile endurance than muscles containing mainly slow-twitch (type I) fibres (soleus). To assess whether differences in Na+-K+ fluxes and excitability might contribute to this phenomenon, we compared excitation-induced Na+-K+ leaks, Na+ channels, Na+-K+ pump capacity, force and compound action potentials (M-waves) in rat EDL and soleus muscles. Isolated muscles were mounted for isometric contractions in Krebs-Ringer bicarbonate buffer and exposed to direct or indirect continuous or intermittent electrical stimulation. The time-course of force decline and concomitant changes in Na+-K+ exchange and M-waves were recorded. During continuous stimulation at 60-120 Hz, EDL showed around fivefold faster rate of force decline than soleus. This was associated with a faster loss of excitability as estimated from the area and amplitude of the M-waves. The net uptake of Na+ and the release of K+ per action potential were respectively 6.5- and 6.6-fold larger in EDL than in soleus, which may in part be due to the larger content of Na+ channels in EDL. During intermittent stimulation with 1 s 60 Hz pulse trains, EDL showed eightfold faster rate of force decline than soleus. The considerably lower contractile endurance of fast-twitch compared with slow-twitch muscles reflects differences in the rate of excitation-induced loss of excitability. This is attributed to the much larger excitation-induced Na+ influx and K+ efflux, leading to a faster rise in [K+]o in fast-twitch muscles. This may only be partly compensated by the concomitant activation of the Na+-K+ pumps, in particular in fibres showing large passive Na+-K+ leaks or reduced content of Na+-K+ pumps. Thus, endurance depends on the leak/pump ratio for Na+ and K+.

Sleep-Dependent Memory Consolidation and Reconsolidation

PubMed Central

Stickgold, Robert; Walker, Matthew P.

2009-01-01

Molecular, cellular, and systems-level processes convert initial, labile memory representations into more permanent ones, available for continued reactivation and recall over extended periods of time. These processes of memory consolidation and reconsolidation are not all-or-none phenomena, but rather a continuing series of biological adjustments that enhance both the efficiency and utility of stored memories over time. In this chapter, we review the role of sleep in supporting these disparate but related processes. PMID:17470412

Recognition Decisions From Visual Working Memory Are Mediated by Continuous Latent Strengths.

PubMed

Ricker, Timothy J; Thiele, Jonathan E; Swagman, April R; Rouder, Jeffrey N

2017-08-01

Making recognition decisions often requires us to reference the contents of working memory, the information available for ongoing cognitive processing. As such, understanding how recognition decisions are made when based on the contents of working memory is of critical importance. In this work we examine whether recognition decisions based on the contents of visual working memory follow a continuous decision process of graded information about the correct choice or a discrete decision process reflecting only knowing and guessing. We find a clear pattern in favor of a continuous latent strength model of visual working memory-based decision making, supporting the notion that visual recognition decision processes are impacted by the degree of matching between the contents of working memory and the choices given. Relation to relevant findings and the implications for human information processing more generally are discussed. Copyright © 2016 Cognitive Science Society, Inc.

Superior memory efficiency of quantum devices for the simulation of continuous-time stochastic processes

NASA Astrophysics Data System (ADS)

Elliott, Thomas J.; Gu, Mile

2018-03-01

Continuous-time stochastic processes pervade everyday experience, and the simulation of models of these processes is of great utility. Classical models of systems operating in continuous-time must typically track an unbounded amount of information about past behaviour, even for relatively simple models, enforcing limits on precision due to the finite memory of the machine. However, quantum machines can require less information about the past than even their optimal classical counterparts to simulate the future of discrete-time processes, and we demonstrate that this advantage extends to the continuous-time regime. Moreover, we show that this reduction in the memory requirement can be unboundedly large, allowing for arbitrary precision even with a finite quantum memory. We provide a systematic method for finding superior quantum constructions, and a protocol for analogue simulation of continuous-time renewal processes with a quantum machine.

Comparison of three continuous positive airway pressure (CPAP) interfaces in healthy Beagle dogs during medetomidine-propofol constant rate infusions.

PubMed

Meira, Carolina; Joerger, Fabiola B; Kutter, Annette P N; Waldmann, Andreas; Ringer, Simone K; Böehm, Stephan H; Iff, Samuel; Mosing, Martina

2018-03-01

To compare the efficacy of three continuous positive airway pressure (CPAP) interfaces in dogs on gas exchange, lung volumes, amount of leak during CPAP and rebreathing in case of equipment failure or disconnection. Randomized, prospective, crossover, experimental trial. Ten purpose-bred Beagle dogs. Dogs were in dorsal recumbency during medetomidine-propofol constant rate infusions, breathing room air. Three interfaces were tested in each dog in a consecutive random order: custom-made mask (M), conical face mask (FM) and helmet (H). End-expiratory lung impedance (EELI) measured by electrical impedance tomography was assessed with no interface (baseline), with the interface only (No-CPAP for 3 minutes) and at 15 minutes of 7 cmH 2 O CPAP (CPAP-delivery). PaO 2 was assessed at No-CPAP and CPAP-delivery, partial pressure of inspired carbon dioxide (PICO 2 ; rebreathing assessment) at No-CPAP and the interface leak (ΔP leak ) at CPAP-delivery. Mixed-effects linear regression models were used for statistical analysis (p<0.05). During CPAP-delivery, all interfaces increased EELI by 7% (p<0.001). Higher ΔP leak was observed with M and H (9 cmH 2 O) in comparison with FM (1 cmH 2 O) (p<0.001). At No-CPAP, less rebreathing occurred with M (0.5 kPa, 4 mmHg) than with FM (1.8 kPa, 14 mmHg) and with H (1.4 kPa, 11 mmHg), but also lower PaO 2 was measured with M (9.3 kPa, 70 mmHg) than with H (11.9 kPa, 90 mmHg) and FM (10.8 kPa, 81 mmHg). All three interfaces can be used to provide adequate CPAP in dogs. The leak during CPAP-delivery and the risk of rebreathing and hypoxaemia, when CPAP is not maintained, can be significant. Therefore, animals should always be supervised during administration of CPAP with any of the three interfaces. The performance of the custom-made M was not superior to the other interfaces. Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

Intraoperative leak testing has no correlation with leak after laparoscopic sleeve gastrectomy.

PubMed

Sethi, Monica; Zagzag, Jonathan; Patel, Karan; Magrath, Melissa; Somoza, Eduardo; Parikh, Manish S; Saunders, John K; Ude-Welcome, Aku; Schwack, Bradley F; Kurian, Marina S; Fielding, George A; Ren-Fielding, Christine J

2016-03-01

Staple line leak is a serious complication of sleeve gastrectomy. Intraoperative methylene blue and air leak tests are routinely used to evaluate for leak; however, the utility of these tests is controversial. We hypothesize that the practice of routine intraoperative leak testing is unnecessary during sleeve gastrectomy. A retrospective cohort study was designed using a prospectively collected database of seven bariatric surgeons from two institutions. All patients who underwent sleeve gastrectomy from March 2012 to November 2014 were included. The performance of intraoperative leak testing and the type of test (air or methylene blue) were based on surgeon preference. Data obtained included BMI, demographics, comorbidity, presence of intraoperative leak test, result of test, and type of test. The primary outcome was leak rate between the leak test (LT) and no leak test (NLT) groups. SAS version 9.4 was used for univariate and multivariate analyses. A total of 1550 sleeve gastrectomies were included; most were laparoscopic (99.8%), except for one converted and two open cases. Routine intraoperative leak tests were performed in 1329 (85.7%) cases, while 221 (14.3%) did not have LTs. Of the 1329 cases with LTs, there were no positive intraoperative results. Fifteen (1%) patients developed leaks, with no difference in leak rate between the LT and NLT groups (1 vs. 1%, p = 0.999). After adjusting for baseline differences between the groups with a propensity analysis, the observed lack of association between leak and intraoperative leak test remained. In this cohort, leaks presented at a mean of 17.3 days postoperatively (range 1-67 days). Two patients with staple line leaks underwent repeat intraoperative leak testing at leak presentation, and the tests remained negative. Intraoperative leak testing has no correlation with leak due to laparoscopic sleeve gastrectomy and is not predictive of the later development of staple line leak.

[Research advances of Tasmayi].

PubMed

Kizaibek, Murat

2013-02-01

Tasmayi (mumie, shilajit) is a pale brown to black substance which leaks from the layers of rocks in many mountain ranges during the warm summer months. In traditional Kazakh medicine, it is used for the treatment of bone fracture and many inflammatory ailments. It is also used as a remedy in the traditional medical systems of many countries such as India, Russia and Kazakhstan. According to the literatures, Tasmayi possesses anti-inflammatory, antiulcerogenic, antibacterial, free radical scavenging, antioxidative, memory enhancing, antidiabetic, antistress, antiallergic, immunomodulative, anti AIDS, anabolic and regeneration stimulating activities. The major physiological action of Tasmayi could be belonging to the presence of dibenzo-alpha-pyrones along with humic and fulvic acids.

D0 Solenoid Upgrade Project: Vacuum Pumping Calculations for the D0 Solenoid

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

Rucinski, R.; /Fermilab

1993-08-02

This engineering note documents the calculations done to determine the vacuum pumping speed for the D-Zero solenoid. The raw calculations are attached. A summary of the results are listed. The vacuum pumping speed of the solenoid is determined by the conductance of the pumping path. At higher pressure ranges during initial pumpdown, the conductances will be rather high. Calculations were not done for the transient pumpdown period, only the steady state type pumping situation. The pressure is assumed to be on the order of 10E-7 torr. This is the free molecular flow regime based on Knudsen number. This pressure regimemore » is also where the pumping speed would be least. The conductances were calculated based on pumping helium gas at a temperature of 300 Kelvin. The total conductance of the pumping path from the solenoid to the inlet of the turbomolecular pump is 11.8 L/s. The effective pumping speed of a 1000 L/s turbo pump attached to this pumping path is 11.7 L/s. The minimum required pumping speed for design purposes was set at 4.3 L/s. This value was arrived at by assuming a warm leak size (10E-8 atm-cc/sec) was not detected during fabrication of the solenoid. It is then assumed that the leak leaks cold liquid helium into the vacuum space. With this leak rate, a 4.3 L/s pumping speed would be able to maintain a 2 x 10E-7 torr pressure in the solenoid vacuum jacket. The solenoid would be able to be operated with this small leak with continuous pumping.« less

[The benefits of digital air leak assessment after pulmonary resection: prospective and comparative study].

PubMed

Mier, José M; Molins, Laureano; Fibla, Juan J

2010-06-01

Persistent air leaks represent the most common pulmonary complication after elective lung resection. Since there are insufficient data in the literature regarding variability in the withdrawal of postoperative pleural drainages, we have designed a prospective, consecutive and comparative study to evaluate if the use of digital devices (Thopaz and DigiVent) to measure postoperative air leak compared to a Pleur-Evac varies on deciding when to withdraw chest tubes after lung resection. A prospective, consecutive and comparative trial was conducted in 75 patients who underwent elective pulmonary resection for non small cell lung cancer. This study compared two digitals devices with the current analogue version in 75 patients. The digital and analogue groups had 26, 24, and 25 patients, respectively. Clinical population data were not statistically different between the groups. The withdrawal of the chest tube was Thopaz, 2.4 days; Digivent, 3.3 days and PleurEvac, 4.5 days. Patients and nurses were subjectively more comfortable with digital devices. Surgeons obtained more objective information with digital devices. The safety mechanism of the Thopaz was also subjectively better, and one patient was discharged home without complications after one week. The digital and continuous measurement of air leak instead of the currently used static analogue systems reduced the chest tube withdrawal and hospital stay by more accurately and reproducibly measuring air leak. Intrapleural pressure curves from the Digivent may also help predict the optimal chest tube setting for each patient. The Thopaz alarm mechanism is very useful to prevent deficiencies in the mechanism and do not required wall suction. Copyright (c) 2010 AEC. Published by Elsevier Espana. All rights reserved.

40 CFR 265.226 - Monitoring and inspection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... operating level for two consecutive months, the amount of liquids in the sumps must be recorded at least... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND... period. (2) After the final cover is installed, the amount of liquids removed from each leak detection...

40 CFR 265.226 - Monitoring and inspection.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operating level for two consecutive months, the amount of liquids in the sumps must be recorded at least... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND... period. (2) After the final cover is installed, the amount of liquids removed from each leak detection...

40 CFR 265.226 - Monitoring and inspection.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operating level for two consecutive months, the amount of liquids in the sumps must be recorded at least... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND... period. (2) After the final cover is installed, the amount of liquids removed from each leak detection...

40 CFR 265.226 - Monitoring and inspection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... operating level for two consecutive months, the amount of liquids in the sumps must be recorded at least... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND... period. (2) After the final cover is installed, the amount of liquids removed from each leak detection...

40 CFR 265.226 - Monitoring and inspection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... operating level for two consecutive months, the amount of liquids in the sumps must be recorded at least... (CONTINUED) INTERIM STATUS STANDARDS FOR OWNERS AND OPERATORS OF HAZARDOUS WASTE TREATMENT, STORAGE, AND... period. (2) After the final cover is installed, the amount of liquids removed from each leak detection...

40 CFR 60.562-2 - Standards: Equipment leaks of VOC.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Volatile Organic Compound (VOC) Emissions from the Polymer Manufacturing Industry § 60.562-2 Standards... feature of the pump whereby polymer fluid used to provide lubrication and/or cooling of the pump shaft...

40 CFR 165.90 - Operational, inspection and maintenance requirements for all new and existing containment...

Code of Federal Regulations, 2012 CFR

2012-07-01

... recovered in a manner that ensures protection of human health and the environment (including surface water... to human health or the environment. (3) Ensure that all materials resulting from spills and leaks and... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PESTICIDE MANAGEMENT AND DISPOSAL...

40 CFR 165.90 - Operational, inspection and maintenance requirements for all new and existing containment...

Code of Federal Regulations, 2014 CFR

2014-07-01

... recovered in a manner that ensures protection of human health and the environment (including surface water... to human health or the environment. (3) Ensure that all materials resulting from spills and leaks and... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PESTICIDE MANAGEMENT AND DISPOSAL...

40 CFR 165.90 - Operational, inspection and maintenance requirements for all new and existing containment...

Code of Federal Regulations, 2011 CFR

2011-07-01

... recovered in a manner that ensures protection of human health and the environment (including surface water... to human health or the environment. (3) Ensure that all materials resulting from spills and leaks and... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PESTICIDE MANAGEMENT AND DISPOSAL...

40 CFR 165.90 - Operational, inspection and maintenance requirements for all new and existing containment...

Code of Federal Regulations, 2013 CFR

2013-07-01

... recovered in a manner that ensures protection of human health and the environment (including surface water... to human health or the environment. (3) Ensure that all materials resulting from spills and leaks and... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PESTICIDE MANAGEMENT AND DISPOSAL...

40 CFR 165.90 - Operational, inspection and maintenance requirements for all new and existing containment...

Code of Federal Regulations, 2010 CFR

2010-07-01

... recovered in a manner that ensures protection of human health and the environment (including surface water... to human health or the environment. (3) Ensure that all materials resulting from spills and leaks and... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS PESTICIDE MANAGEMENT AND DISPOSAL...

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) [Reserved] (3) Be designed and operated to capture and transport all the purged process fluid to a control... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1032 Sampling... design and operation. Each closed-purge, closed-loop, or closed vent system as required in paragraph (b...

40 CFR 63.1013 - Sampling connection systems standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 1 § 63.1013 Sampling connection... container are not required to be collected or captured. (c) Equipment design and operation. Each closed... process fluid to a process; or (3) Be designed and operated to capture and transport all the purged...

40 CFR 63.1032 - Sampling connection systems standards.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) [Reserved] (3) Be designed and operated to capture and transport all the purged process fluid to a control... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1032 Sampling... design and operation. Each closed-purge, closed-loop, or closed vent system as required in paragraph (b...

40 CFR 60.5200 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2012 CFR

2012-07-01

... control if the conditions of paragraph (a)(7)(i)(A) or (a)(7)(i)(B) of this section are met. (A) The zero... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.5200 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2014 CFR

2014-07-01

... control if the conditions of paragraph (a)(7)(i)(A) or (a)(7)(i)(B) of this section are met. (A) The zero... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 60.5200 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2013 CFR

2013-07-01

... control if the conditions of paragraph (a)(7)(i)(A) or (a)(7)(i)(B) of this section are met. (A) The zero... representative of the relative or absolute particulate matter loadings for each exhaust stack, roof vent, or...

40 CFR 62.14454 - How must I monitor the required parameters?

Code of Federal Regulations, 2014 CFR

2014-07-01

... installed in each baghouse compartment or cell. (7) For negative pressure or induced air FF, the bag leak...) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS FOR DESIGNATED FACILITIES AND... use an air pollution control device that includes a FF and are not demonstrating compliance using PM...

40 CFR 62.14454 - How must I monitor the required parameters?

Code of Federal Regulations, 2013 CFR

2013-07-01

... installed in each baghouse compartment or cell. (7) For negative pressure or induced air FF, the bag leak...) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS FOR DESIGNATED FACILITIES AND... use an air pollution control device that includes a FF and are not demonstrating compliance using PM...

Propofol and midazolam inhibit conscious memory processes very soon after encoding: an event-related potential study of familiarity and recollection in volunteers.

PubMed

Veselis, Robert A; Pryor, Kane O; Reinsel, Ruth A; Li, Yuelin; Mehta, Meghana; Johnson, Ray

2009-02-01

Intravenous drugs active via gamma-aminobutyric acid receptors to produce memory impairment during conscious sedation. Memory function was assessed using event-related potentials (ERPs) while drug was present. The continuous recognition task measured recognition of photographs from working (6 s) and long-term (27 s) memory while ERPs were recorded from Cz (familiarity recognition) and Pz electrodes (recollection recognition). Volunteer participants received sequential doses of one of placebo (n = 11), 0.45 and 0.9 microg/ml propofol (n = 10), 20 and 40 ng/ml midazolam (n = 12), 1.5 and 3 microg/ml thiopental (n = 11), or 0.25 and 0.4 ng/ml dexmedetomidine (n = 11). End-of-day yes/no recognition 225 min after the end of drug infusion tested memory retention of pictures encoded on the continuous recognition tasks. Active drugs increased reaction times and impaired memory on the continuous recognition task equally, except for a greater effect of midazolam (P < 0.04). Forgetting from continuous recognition tasks to end of day was similar for all drugs (P = 0.40), greater than placebo (P < 0.001). Propofol and midazolam decreased the area between first presentation (new) and recognized (old, 27 s later) ERP waveforms from long-term memory for familiarity (P = 0.03) and possibly for recollection processes (P = 0.12). Propofol shifted ERP amplitudes to smaller voltages (P < 0.002). Dexmedetomidine may have impaired familiarity more than recollection processes (P = 0.10). Thiopental had no effect on ERPs. Propofol and midazolam impaired recognition ERPs from long-term memory but not working memory. ERP measures of memory revealed different pathways to end-of-day memory loss as early as 27 s after encoding.

OVERVIEW OF ENHANCED HANFORD SINGLE-SHELL TANK (SST) INTEGRITY PROJECT - 12128

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

VENETZ TJ; BOOMER KD; WASHENFELDER DJ

2012-01-25

To improve the understanding of the single-shell tanks integrity, Washington River Protection Solutions, LLC, the USDOE Hanford Site tank contractor, developed an enhanced Single-Shell Tank (SST) Integrity Project in 2009. An expert panel on SST integrity, consisting of various subject matters experts in industry and academia, was created to provide recommendations supporting the development of the project. This panel developed 33 recommendations in four main areas of interest: structural integrity, liner degradation, leak integrity and prevention, and mitigation of contamination migration, Seventeen of these recommendations were used to develop the basis for the M-45-10-1 Change Package for the Hanford Federalmore » Agreement and Compliance Order, which is also known as the Tri-Party Agreement. The change package identified two phases of work for SST integrity. The initial phase has been focused on efforts to envelope the integrity of the tanks. The initial phase was divided into two primary areas of investigation: structural integrity and leak integrity. If necessary based on the outcome from the initial work, a second phase would be focused on further definition of the integrity of the concrete and liners. Combined these two phases are designed to support the formal integrity assessment of the Hanford SSTs in 2018 by Independent Qualified Registered Engineer. The work to further define the DOE's understanding of the structural integrity SSTs involves preparing a modern Analysis of Record using a finite element analysis program. Structural analyses of the SSTs have been conducted since 1957, but these analyses used analog calculation, less rigorous models, or focused on individual structures. As such, an integrated understanding of all of the SSTs has not been developed to modern expectations. In support of this effort, other milestones will address the visual inspection of the tank concrete and the collection of concrete core samples from the tanks for analysis of current mechanics properties. The work on the liner leak integrity has examined the leaks from 23 tanks with liner failures. Individual leak assessments are being developed for each tank to identify the leak cause and location. Also a common cause study is being performed to take the data from individual tanks to look for trends in the failure. Supporting this work is an assessment of the leak rate from tanks at both Hanford and the Savannah River Site and a new method to locate leak sites in tank liner using ionic conductivity. A separate activity is being conducted to examine the propensity for corrosion in select single shell tanks with aggressive waste layers. The work for these two main efforts will provide the basis for the phase two planning. If the margins identified aren't sufficient to ensure the integrity through the life of the mission, phase two would focus on activities to further enhance the understanding of tank integrity. Also coincident with any phase-two work would be the integrity analysis for the tanks, which would be complete in 2018. With delays in the completion of waste treatment facilities at Hanford, greater reliance on safe, continued storage of waste in the single shell tanks is increased in importance. The goal of integrity assessment would provide basis to continue SST activities till the end of the treatment mission.« less

International Space Station Node 1 is moved for leak test

NASA Technical Reports Server (NTRS)

1998-01-01

Node 1, the first element for the International Space Station, and attached Pressurized Mating Adapter-1 continue with prelaunch preparation activities at KSC's Space Station Processing Facility. Node 1 is a connecting passageway to the living and working areas of the space station. The node is seen here being moved into the Shuttle payload transportation canister, where the doors will be closed for a two-week leak check. The node was moved to the canister from the element rotation stand, or test stand, where it underwent an interim weight and center of gravity determination. The final determination is planned to be performed prior to transporting Node 1 to the launch pad. Node 1 is scheduled to fly on STS-88.

International Space Station Node 1 is moved for leak test

NASA Technical Reports Server (NTRS)

1998-01-01

Node 1, the first U.S. element for the International Space Station, and attached Pressurized Mating Adapter-1 continue with prelaunch preparation activities at KSC's Space Station Processing Facility. Node 1 is a connecting passageway to the living and working areas of the space station. The node and PMA-1 are being removed from the element rotation stand, or test stand, where they underwent an interim weight and center of gravity determination. (The final determination is planned to be performed prior to transporting Node 1 to the launch pad.) Now the node is being moved to the Shuttle payload transportation canister, where the doors will be closed for a two-week leak check. Node 1 is scheduled to fly on STS-88.

Sample Delivery and Computer Control Systems for Detecting Leaks in the Main Engines of the Space Shuttle

NASA Technical Reports Server (NTRS)

Griffin, Timothy P.; Naylor, Guy R.; Hritz, Richard J.; Barrett, Carolyn A.

1997-01-01

The main engines of the Space Shuttle use hydrogen and oxygen as the fuel and oxidant. The explosive and fire hazards associated with these two components pose a serious danger to personnel and equipment. Therefore prior to use the main engines undergo extensive leak tests. Instead of using hazardous gases there tests utilize helium as the tracer element. This results in a need to monitor helium in the ppm level continuously for hours. The major challenge in developing such a low level gas monitor is the sample delivery system. This paper discuss a system developed to meet the requirements while also being mobile. Also shown is the calibration technique, stability, and accuracy results for the system.

ERP Correlates of Target-Distracter Differentiation in Repeated Runs of a Continuous Recognition Task with Emotional and Neutral Faces

ERIC Educational Resources Information Center

Treese, Anne-Cecile; Johansson, Mikael; Lindgren, Magnus

2010-01-01

The emotional salience of faces has previously been shown to induce memory distortions in recognition memory tasks. This event-related potential (ERP) study used repeated runs of a continuous recognition task with emotional and neutral faces to investigate emotion-induced memory distortions. In the second and third runs, participants made more…

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

PubMed

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

2016-06-01

Fugitive emissions from natural gas systems are the largest anthropogenic source of the greenhouse gas methane (CH4) in the U.S. and contribute to the risk of explosions in urban environments. Here, we report on a survey of CH4 emissions from 100 natural gas leaks in cast iron distribution mains in Metro Boston, MA. Direct measures of CH4 flux from individual leaks ranged from 4.0 - 2.3 × 10(4) g CH4•day(-1). The distribution of leak size is positively skewed, with 7% of leaks contributing 50% of total CH4 emissions measured. We identify parallels in the skewed distribution of leak size found in downstream systems with midstream and upstream stages of the gas process chain. Fixing 'superemitter' leaks will disproportionately stem greenhouse gas emissions. Fifteen percent of leaks surveyed qualified as potentially explosive (Grade 1), and we found no difference in CH4 flux between Grade 1 leaks and all remaining leaks surveyed (p = 0.24). All leaks must be addressed, as even small leaks cannot be disregarded as 'safely leaking.' Key methodological impediments to quantifying and addressing the impacts of leaking natural gas distribution infrastructure involve inconsistencies in the manner in which gas leaks are defined, detected, and classified. To address this need, we propose a two-part leak classification system that reflects both the safety and climatic impacts of natural gas leaks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Epoxy/Polycaprolactone Systems with Triple-Shape Memory Effect: Electrospun Nanoweb with and without Graphene Versus Co-Continuous Morphology

PubMed Central

Fejős, Márta; Molnár, Kolos; Karger-Kocsis, József

2013-01-01

Triple-shape memory epoxy (EP)/polycaprolactone (PCL) systems (PCL content: 23 wt %) with different structures (PCL nanoweb embedded in EP matrix and EP/PCL with co-continuous phase structure) were produced. To set the two temporary shapes, the glass transition temperature (Tg) of the EP and the melting temperature (Tm) of PCL served during the shape memory cycle. An attempt was made to reinforce the PCL nanoweb by graphene nanoplatelets prior to infiltrating the nanoweb with EP through vacuum assisted resin transfer molding. Morphology was analyzed by scanning electron microscopy and Raman spectrometry. Triple-shape memory characteristics were determined by dynamic mechanical analysis in tension mode. Graphene was supposed to act also as spacer between the nanofibers, improving the quality of impregnation with EP. The EP phase related shape memory properties were similar for all systems, while those belonging to PCL phase depended on the structure. Shape fixity of PCL was better without than with graphene reinforcement. The best shape memory performance was shown by the EP/PCL with co-continuous structure. Based on Raman spectrometry results, the characteristic dimension of the related co-continuous network was below 900 nm. PMID:28788342

Factors impacting cerebrospinal fluid leak rates in endoscopic sellar surgery.

PubMed

Karnezis, Tom T; Baker, Andrew B; Soler, Zachary M; Wise, Sarah K; Rereddy, Shruthi K; Patel, Zara M; Oyesiku, Nelson M; DelGaudio, John M; Hadjipanayis, Constantinos G; Woodworth, Bradford A; Riley, Kristen O; Lee, John; Cusimano, Michael D; Govindaraj, Satish; Psaltis, Alkis; Wormald, Peter John; Santoreneos, Steve; Sindwani, Raj; Trosman, Samuel; Stokken, Janalee K; Woodard, Troy D; Recinos, Pablo F; Vandergrift, W Alexander; Schlosser, Rodney J

2016-11-01

In patients undergoing transnasal endoscopic sellar surgery, an analysis of risk factors and predictors of intraoperative and postoperative cerebrospinal fluid leak (CSF) would provide important prognostic information. A retrospective review of patients undergoing endoscopic sellar surgery for pituitary adenomas or craniopharyngiomas between 2002 and 2014 at 7 international centers was performed. Demographic, comorbidity, and tumor characteristics were evaluated to determine the associations between intraoperative and postoperative CSF leaks. Correlations between reconstructive and CSF diversion techniques were associated with postoperative CSF leak rates. Odds ratios (OR) were identified using a multivariate logistic regression model. Data were collected on 1108 pituitary adenomas and 53 craniopharyngiomas. Overall, 30.1% of patients had an intraoperative leak and 5.9% had a postoperative leak. Preoperative factors associated with increased intraoperative leaks were mild liver disease, craniopharyngioma, and extension into the anterior cranial fossa. In patients with intraoperative CSF leaks, postoperative leaks occurred in 10.3%, with a higher postoperative leak rate in craniopharyngiomas (20.8% vs 5.1% in pituitary adenomas). Once an intraoperative leak occurred, craniopharyngioma (OR = 4.255, p = 0.010) and higher body mass index (BMI) predicted postoperative leak (OR = 1.055, p = 0.010). In patients with an intraoperative leak, the use of septal flaps reduced the occurrence of postoperative leak (OR = 0.431, p = 0.027). Rigid reconstruction and CSF diversion techniques did not impact postoperative leak rates. Intraoperative CSF leaks can occur during endoscopic sellar surgery, especially in larger tumors or craniopharyngiomas. Once an intraoperative leak occurs, risk factors for postoperative leaks include craniopharyngiomas and higher BMI. Use of septal flaps decreases this risk. © 2016 ARS-AAOA, LLC.

40 CFR 63.3968 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... temperature simulation devices. (v) Conduct a visual inspection of each sensor every quarter if redundant... signal simulations or via relative accuracy testing. (v) Conduct an accuracy audit every quarter and... signal simulations or via relative accuracy testing. (vi) Perform leak checks monthly. (vii) Perform...

40 CFR 63.3968 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... temperature simulation devices. (v) Conduct a visual inspection of each sensor every quarter if redundant... signal simulations or via relative accuracy testing. (v) Conduct an accuracy audit every quarter and... signal simulations or via relative accuracy testing. (vi) Perform leak checks monthly. (vii) Perform...

40 CFR 63.3968 - What are the requirements for continuous parameter monitoring system installation, operation, and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... temperature simulation devices. (v) Conduct a visual inspection of each sensor every quarter if redundant... signal simulations or via relative accuracy testing. (v) Conduct an accuracy audit every quarter and... signal simulations or via relative accuracy testing. (vi) Perform leak checks monthly. (vii) Perform...

AGOR 28

DTIC Science & Technology

2016-04-08

the JW pump on #4 twice due to small oil seal leaks on the pump shaft . Will continue to monitor. • Condensate Drains – Condensate from SCU’s, Fan...report to us. In addition, AF will be applied to the tail shafts as requested. The yard will then do a full coat of AF on the hull, including any

40 CFR 455.40 - Applicability; description of the pesticide formulating, packaging and repackaging subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and emergency operation of safety showers and eye washes; storm water; Department of Transportation (DOT) aerosol leak test bath water from non-continuous overflow baths (batch baths) where no cans have burst from the time of the last water change-out; and on-site laboratories from cleaning analytical...

40 CFR 63.1452 - What are my monitoring requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... integrity, all electrical connections for continuity, and all mechanical connections for leakage. (6) Record... subject to the operating limit in § 63.1444(f) or § 63.1446(c) for the bag leak detection system alarm... detection system according to the requirements in paragraph (b)(1) of this section and conduct regular...

40 CFR 63.7294 - What work practice standard must I meet for soaking?

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants for Coke Ovens: Pushing... standard must I meet for soaking? (a) For each new and existing by-product coke oven battery, you must... from raw coke oven gas leaking from the collecting main through the damper, and emissions that result...

40 CFR 455.40 - Applicability; description of the pesticide formulating, packaging and repackaging subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and emergency operation of safety showers and eye washes; storm water; Department of Transportation (DOT) aerosol leak test bath water from non-continuous overflow baths (batch baths) where no cans have burst from the time of the last water change-out; and on-site laboratories from cleaning analytical...

40 CFR 63.1087 - What actions must I take if a leak is detected?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Repair Requirements for Heat Exchange Systems § 63.1087 What actions must I take if a... within 7 calendar days of the repair or startup, whichever is later, to confirm that the heat exchange...

40 CFR 63.1087 - What actions must I take if a leak is detected?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Repair Requirements for Heat Exchange Systems § 63.1087 What actions must I take if a... within 7 calendar days of the repair or startup, whichever is later, to confirm that the heat exchange...

40 CFR 63.1087 - What actions must I take if a leak is detected?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Repair Requirements for Heat Exchange Systems § 63.1087 What actions must I take if a... within 7 calender days of the repair or startup, whichever is later, to confirm that the heat exchange...

40 CFR 63.1087 - What actions must I take if a leak is detected?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Repair Requirements for Heat Exchange Systems § 63.1087 What actions must I take if a... within 7 calendar days of the repair or startup, whichever is later, to confirm that the heat exchange...

40 CFR 63.1087 - What actions must I take if a leak is detected?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Ethylene Manufacturing Process Units: Heat Exchange Systems and Waste Operations Repair Requirements for Heat Exchange Systems § 63.1087 What actions must I take if a... within 7 calender days of the repair or startup, whichever is later, to confirm that the heat exchange...

40 CFR Table 6 to Subpart Ffff of... - Requirements for Equipment Leaks

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Miscellaneous Organic Chemical Manufacturing Pt. 63, Subpt. FFFF, Table 6 Table 6 to Subpart FFFF of Part 63—Requirements for... in organic HAP service a. Comply with the requirements of subpart UU of this part 63 and the...

40 CFR 63.8665 - What definitions apply to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... defined in the Clean Air Act, in § 63.2, and in this section as follows: Air pollution control device (APCD) means any equipment that reduces the quantity of a pollutant that is emitted to the air. Bag leak...? 63.8665 Section 63.8665 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

40 CFR 63.8665 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... defined in the Clean Air Act, in § 63.2, and in this section as follows: Air pollution control device (APCD) means any equipment that reduces the quantity of a pollutant that is emitted to the air. Bag leak...? 63.8665 Section 63.8665 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

40 CFR 63.8665 - What definitions apply to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... defined in the Clean Air Act, in § 63.2, and in this section as follows: Air pollution control device (APCD) means any equipment that reduces the quantity of a pollutant that is emitted to the air. Bag leak...? 63.8665 Section 63.8665 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

40 CFR 63.8665 - What definitions apply to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... defined in the Clean Air Act, in § 63.2, and in this section as follows: Air pollution control device (APCD) means any equipment that reduces the quantity of a pollutant that is emitted to the air. Bag leak...? 63.8665 Section 63.8665 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR...

Education Pipeline. Forum Focus. Volume 2, Issue 4, September-October 2004

ERIC Educational Resources Information Center

Yohalem, Nicole; Joselowsky, Francine; Allen, Lili

2004-01-01

While the nation's public systems continue to fall short of delivering equitable educational supports to children and youth, youth workers have spent the last several decades insulating and, in some cases, patching the leaks in the "education pipeline"--a term describing the route students follow from early childhood through…

40 CFR 60.56c - Compliance and performance testing.

Code of Federal Regulations, 2011 CFR

2011-07-01

....56c Section 60.56c Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (defined oxygen correction basis); 20.9=oxygen concentration in air, percent; and %O2=oxygen concentration... compliance with the PM standards using bag leak detection systems as specified in § 60.57c(h) or PM CEMS as...

40 CFR 60.56c - Compliance and performance testing.

Code of Federal Regulations, 2010 CFR

2010-07-01

....56c Section 60.56c Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... (defined oxygen correction basis); 20.9=oxygen concentration in air, percent; and %O2=oxygen concentration... compliance with the PM standards using bag leak detection systems as specified in § 60.57c(h) or PM CEMS as...

Space Shuttle reaction control system thruster metal nitrate removal and characterization

NASA Technical Reports Server (NTRS)

Saulsberry, R. L.; Mccartney, P. A.

1993-01-01

The Space Shuttle hypergolic primary reaction control system (PRCS) thrusters continue to fail-leak or fail-off at a rate of approximately 1.5 per flight, attributed primarily to metal nitrate formation in the nitrogen tetroxide (N2O4) pilot operated valves (POV's). The failures have continued despite ground support equipment (GSE) and subsystem operational improvements. As a result, the Johnson Space Center (JSC) White Sands Test Facility (WSTF) performed a study to characterize the contamination in the N204 valves. This study prompted the development and implementation of a highly successful flushing technique using deionized (DI) water and gaseous nitrogen (GN2) to remove the contamination while minimizing Teflon seat damage. Following flushing a comprehensive acceptance test is performed before the thruster is deemed recovered. Between the time WSTF was certified to process flight thrusters (March 1992) and September 1993, a 68 percent thruster recovery rate was achieved. The contamination flushed from these thrusters was analyzed and has provided insight into the corrosion process, which is reported in this publication. Additionally, the long-term performance of 24 flushed thrusters installed in the WSTF Fleet Leader Shuttle reaction control subsystem (RCS) test articles is being assessed. WSTF continues to flush flight and test article thrusters and compile data to investigate metal nitrate formation characteristics in leaking and nonleaking valves.

A Two-Phase Model of Resource Allocation in Visual Working Memory

ERIC Educational Resources Information Center

Ye, Chaoxiong; Hu, Zhonghua; Li, Hong; Ristaniemi, Tapani; Liu, Qiang; Liu, Taosheng

2017-01-01

Two broad theories of visual working memory (VWM) storage have emerged from current research, a discrete slot-based theory and a continuous resource theory. However, neither the discrete slot-based theory or continuous resource theory clearly stipulates how the mental commodity for VWM (discrete slot or continuous resource) is allocated.…

Continuous-variable quantum computing in optical time-frequency modes using quantum memories.

PubMed

Humphreys, Peter C; Kolthammer, W Steven; Nunn, Joshua; Barbieri, Marco; Datta, Animesh; Walmsley, Ian A

2014-09-26

We develop a scheme for time-frequency encoded continuous-variable cluster-state quantum computing using quantum memories. In particular, we propose a method to produce, manipulate, and measure two-dimensional cluster states in a single spatial mode by exploiting the intrinsic time-frequency selectivity of Raman quantum memories. Time-frequency encoding enables the scheme to be extremely compact, requiring a number of memories that are a linear function of only the number of different frequencies in which the computational state is encoded, independent of its temporal duration. We therefore show that quantum memories can be a powerful component for scalable photonic quantum information processing architectures.

Prospective randomized trial compares suction versus water seal for air leaks.

PubMed

Cerfolio, R J; Bass, C; Katholi, C R

2001-05-01

Surgeons treat air leaks differently. Our goal was to evaluate whether it is better to place chest tubes on suction or water seal for stopping air leaks after pulmonary surgery. A second goal was to evaluate a new classification system for air leaks that we developed. Patients were prospectively randomized before surgery to receive suction or water seal to their chest tubes on postoperative day (POD) #2. Air leaks were described and quantified daily by a classification system and a leak meter. The air-leak meter scored leaks from 1 (least) to 7 (greatest). The group randomized to water seal stayed on water seal unless a pneumothorax developed. On POD #2, 33 of 140 patients had an air leak. Eighteen patients had been preoperatively randomized to water seal and 15 to suction. Air leaks resolved in 12 (67%) of the water seal patients by the morning of POD #3. All 6 patients whose air leak did not stop had a leak that was 4/7 or greater (p < 0.0001) on the leak meter. Of the 15 patients randomized to suction, only 1 patient's air leak (7%) resolved by the morning of POD #3. The randomization aspect of the trial was ended and statistical analysis showed water seal was superior (p = 0.001). The remaining 14 patients were then placed to water seal and by the morning of POD #4, 13 patients' leaks had stopped. Of the 32 total patients placed to seal, 7 (22%) developed a pneumothorax and 6 of these 7 patients had leaks that were 4/7 or greater (p = 0.001). Placing chest tubes on water seal seems superior to wall suction for stopping air leaks after pulmonary resection. However, water seal does not stop expiratory leaks that are 4/7 or greater. Pneumothorax may occur when chest tubes are placed on seal with leaks this large.

Measurement device-independent quantum dialogue

NASA Astrophysics Data System (ADS)

Maitra, Arpita

2017-12-01

Very recently, the experimental demonstration of quantum secure direct communication (QSDC) with state-of-the-art atomic quantum memory has been reported (Zhang et al. in Phys Rev Lett 118:220501, 2017). Quantum dialogue (QD) falls under QSDC where the secrete messages are communicated simultaneously between two legitimate parties. The successful experimental demonstration of QSDC opens up the possibilities for practical implementation of QD protocols. Thus, it is necessary to analyze the practical security issues of QD protocols for future implementation. Since the very first proposal for QD by Nguyen (Phys Lett A 328:6-10, 2004), a large number of variants and extensions have been presented till date. However, all of those leak half of the secret bits to the adversary through classical communications of the measurement results. In this direction, motivated by the idea of Lo et al. (Phys Rev Lett 108:130503, 2012), we propose a measurement device-independent quantum dialogue scheme which is resistant to such information leakage as well as side-channel attacks. In the proposed protocol, Alice and Bob, two legitimate parties, are allowed to prepare the states only. The states are measured by an untrusted third party who may himself behave as an adversary. We show that our protocol is secure under this adversarial model. The current protocol does not require any quantum memory, and thus, it is inherently robust against memory attacks. Such robustness might not be guaranteed in the QSDC protocol with quantum memory (Zhang et al. 2017).

Additional diagnostic value of multiplane echocardiography over biplane imaging in assessment of mitral prosthetic valves.

PubMed Central

Faletra, F.; De Chiara, F.; Corno, R.; Passini, L.

1996-01-01

OBJECTIVE: To evaluate how often multiplane transoesophageal echocardiography yields new or complementary data in mitral prostheses in comparison with the exclusive use of biplane imaging. PATIENTS: 73 consecutive patients with mitral prostheses who underwent multiplane transoesophageal echocardiograpy between January 1993 and December 1994. METHODS: Biplane images (transverse and longitudinal planes) and multiplane images (transverse, longitudinal, and intermediate planes) were recorded on two separate videotapes. The data provided by multiplane transoesophageal echocardiography were evaluated as (a) new data (abnormalities missed by biplane imaging); (b) complementary data (better delineating lesions already visualised by biplane imaging); or (c) redundant data (data already provided by biplane imaging). RESULTS: Multiplane transoesophageal echocardiography revealed new abnormalities in seven patients (9.5%) (thrombi in three and paraprosthetic leaks in the remaining four) and complementary data in nine (12.3%). In patients with paraprosthetic regurgitation, the possibility of continuously visualising the sewing ring by means of sequential angulations allowed the circumferential extension of the leak to be measured. In seven patients with paravalvar regurgitation who underwent surgery, the extension of the leak as measured by the multiplane approach closely corresponded with the surgical data. CONCLUSIONS: In comparison with the exclusive use of biplane imaging, the multiplane approach added new or complementary data in a significant proportion of patients with mitral prostheses. The ability to obtain the sequential adjacent planes allowed a more reliable appraisal of the extension of the leak and other abnormalities. Images PMID:8697166

Aging Behavior of the EPDM O-Rings in the H1616 Shipping Package

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

Daugherty, W.; Stefek, T.; Skidmore, E.

The H1616 shipping package is used within the DOE complex for shipping tritium reservoirs. The annual recertification frequency can create logistical difficulties with other constraints on the timing of shipments; thus, a longer re-certification period is desirable. The ethylene propylene diene monomer (EPDM) O-rings used in the H1616 shipping package are being aged and tested at the Savannah River National Laboratory (SRNL) to provide a technical basis for extending the annual maintenance of the H1616 shipping package. H1616 EPDM O-rings are being aged at elevated temperature, and tested for degradation in mechanical properties, compression stress relaxation (CSR) behavior, and leakmore » performance. Mechanical properties of aged O-rings show significant degradation can occur, but an inert atmosphere (argon backfill) greatly reduces the rate of degradation. The CSR behavior of O-rings was evaluated in air at 79 to 177 °C. These collective data were used to develop a predictive model for extrapolation of CSR behavior to relevant service temperatures (<67 °C). O-rings were also aged in H1616 Containment Vessels (CV) in an inert atmosphere at 71 to 149 °C. The vessels are helium leak tested periodically to determine if they continue to remain leak-tight. The vessel tests provide a solid demonstration that the H1616 O-rings will remain leak-tight at temperatures up to 113 °C for up to approximately 2.3 years. Significantly longer periods of leak-tight service are expected at the lower temperatures actually experienced in service. The predictive model developed from the CSR data conservatively indicates a service life of ~5 years at 67 °C. Although the relationship between CSR behavior and leak-tight performance has not been established for this design, the CSR predictions for this O-ring are conservative relative to leak-tight performance. Based on the collective data developed to date, SRNL has recommended that the maintenance interval for the H1616 package be extended from 1 year to 2 years. Future recommendations in support of even longer maintenance intervals are expected, as additional aging data become available.« less

Pharmaceutical container/closure integrity. I: Mass spectrometry-based helium leak rate detection for rubber-stoppered glass vials.

PubMed

Kirsch, L E; Nguyen, L; Moeckly, C S

1997-01-01

The development of mass spectrometry-based leak detection for pharmaceutical container integrity was undertaken to provide an alternative to microbial challenge testing. Standard 10-mL vials were modified to contain pinholes (0.5 to 10 microns) by affixing micropipettes with epoxy into 2-mm vial side wall holes. The absolute leak rate was determined using vials that were sealed in a tracer (helium) environment with butyl rubber stoppers and crimps. Alternatively leak rates were determined using vials that were sealed in room air and exposed to tracer under pressure (charging or bombing). Tracer leak rates were measured with mass spectrometry leak rate detectors. The absolute leak rate was correlated the squared nominal leak radius which suggested that the mode of gas flow through the glass pipette leaks was more turbulent than viscous even at low leak rates typically associated with viscous flow. The minimum observed absolute leak rate was about 10(-6.6) std cc/sec and was likely due to helium permeation through the rubber stoppers. Heat-stressed rubber stoppers did not affect the baseline absolute leak rate. Adsorption of helium tracer to the test unit surfaces was found to confound baseline leak rate measurement reliability but was eliminated as a source of variation by exposing the test units to ambient air for > or = 12 hours. The absolute leak rate and the leak rate measured after charging were related in a mathematically predictable way.

Precision of working memory for speech sounds.

PubMed

Joseph, Sabine; Iverson, Paul; Manohar, Sanjay; Fox, Zoe; Scott, Sophie K; Husain, Masud

2015-01-01

Memory for speech sounds is a key component of models of verbal working memory (WM). But how good is verbal WM? Most investigations assess this using binary report measures to derive a fixed number of items that can be stored. However, recent findings in visual WM have challenged such "quantized" views by employing measures of recall precision with an analogue response scale. WM for speech sounds might rely on both continuous and categorical storage mechanisms. Using a novel speech matching paradigm, we measured WM recall precision for phonemes. Vowel qualities were sampled from a formant space continuum. A probe vowel had to be adjusted to match the vowel quality of a target on a continuous, analogue response scale. Crucially, this provided an index of the variability of a memory representation around its true value and thus allowed us to estimate how memories were distorted from the original sounds. Memory load affected the quality of speech sound recall in two ways. First, there was a gradual decline in recall precision with increasing number of items, consistent with the view that WM representations of speech sounds become noisier with an increase in the number of items held in memory, just as for vision. Based on multidimensional scaling (MDS), the level of noise appeared to be reflected in distortions of the formant space. Second, as memory load increased, there was evidence of greater clustering of participants' responses around particular vowels. A mixture model captured both continuous and categorical responses, demonstrating a shift from continuous to categorical memory with increasing WM load. This suggests that direct acoustic storage can be used for single items, but when more items must be stored, categorical representations must be used.

Working Memory and Reinforcement Schedule Jointly Determine Reinforcement Learning in Children: Potential Implications for Behavioral Parent Training

PubMed Central

Segers, Elien; Beckers, Tom; Geurts, Hilde; Claes, Laurence; Danckaerts, Marina; van der Oord, Saskia

2018-01-01

Introduction: Behavioral Parent Training (BPT) is often provided for childhood psychiatric disorders. These disorders have been shown to be associated with working memory impairments. BPT is based on operant learning principles, yet how operant principles shape behavior (through the partial reinforcement (PRF) extinction effect, i.e., greater resistance to extinction that is created when behavior is reinforced partially rather than continuously) and the potential role of working memory therein is scarcely studied in children. This study explored the PRF extinction effect and the role of working memory therein using experimental tasks in typically developing children. Methods: Ninety-seven children (age 6–10) completed a working memory task and an operant learning task, in which children acquired a response-sequence rule under either continuous or PRF (120 trials), followed by an extinction phase (80 trials). Data of 88 children were used for analysis. Results: The PRF extinction effect was confirmed: We observed slower acquisition and extinction in the PRF condition as compared to the continuous reinforcement (CRF) condition. Working memory was negatively related to acquisition but not extinction performance. Conclusion: Both reinforcement contingencies and working memory relate to acquisition performance. Potential implications for BPT are that decreasing working memory load may enhance the chance of optimally learning through reinforcement. PMID:29643822

Non-invasive positive-pressure ventilation with positive end-expiratory pressure counteracts inward air leaks during preoxygenation: a randomised crossover controlled study in healthy volunteers.

PubMed

Hanouz, J-L; Le Gall, F; Gérard, J-L; Terzi, N; Normand, H

2018-04-01

During preoxygenation, the lack of tight fit between the mask and the patient's face results in inward air leak preventing effective preoxygenation. We hypothesized that non-invasive positive-pressure ventilation and positive end-expiratory pressure (PEEP) could counteract inward air leak. Healthy volunteers were randomly assigned to preoxygenated through spontaneous breathing without leak (SB), spontaneous breathing with a calibrated air leak (T-shaped piece between the mouth and the breathing system; SB-leak), or non-invasive positive inspiratory pressure ventilation (inspiratory support +6 cm H 2 O; PEEP +5 cm H 2 O) with calibrated leak (PPV-leak). The volunteers breathed through a mouthpiece connected to an anaesthesia ventilator. The expired oxygen fraction (FeO 2 ) and air-leak flow (ml s -1 ) were measured. The primary end point was the proportion of volunteers with FeO 2 >90% at 3 min. The secondary end points were FeO 2 at 3 min, time to reach FeO 2 of 90%, and the inspiratory air-leak flow. Twenty healthy volunteers were included. The proportion of volunteers with FeO 2 >90% at 3 min was 0% in the SB-leak group, 95% in the SB group, and 100% in the PPV-leak group (P<0.001). At 3 min, the mean [standard deviation (sd)] FeO 2 was 89 (1)%, 76 (1)%, and 90 (0)% in the SB, SB-leak, and PPV-leak groups, respectively (P<0.001). The mean (sd) inward air leak was 59 (12) ml s -1 in the SB-leak group, but 0 (0) ml s -1 in the PPV-leak group (P<0.001). Preoxygenation through non-invasive positive-pressure ventilation and PEEP provided effective preoxygenation despite an inward air leak. NCT03087825. Copyright © 2017 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

Continuous Time Random Walks with memory and financial distributions

NASA Astrophysics Data System (ADS)

Montero, Miquel; Masoliver, Jaume

2017-11-01

We study financial distributions from the perspective of Continuous Time Random Walks with memory. We review some of our previous developments and apply them to financial problems. We also present some new models with memory that can be useful in characterizing tendency effects which are inherent in most markets. We also briefly study the effect on return distributions of fractional behaviors in the distribution of pausing times between successive transactions.

Novel de novo synthesized phosphate carrier compound ABA-PEG20k-Pi20 suppresses collagenase production in Enterococcus faecalis and prevents colonic anastomotic leak in an experimental model.

PubMed

Wiegerinck, M; Hyoju, S K; Mao, J; Zaborin, A; Adriaansens, C; Salzman, E; Hyman, N H; Zaborina, O; van Goor, H; Alverdy, J C

2018-04-16

Previous work has demonstrated that anastomotic leak can be caused by collagenolytic bacteria such as Enterococcus faecalis via an effect on wound collagen. In humans, E. faecalis is the organism cultured most commonly from a leaking anastomosis, and is not routinely eliminated by standard oral or intravenous antibiotics. Novel strategies are needed to contain the virulence of this pathogen when present on anastomotic tissues. Polyphosphorylated polymer ABA-PEG20k-Pi20 was tested in mice for its ability to prevent anastomotic leak caused by collagenolytic E. faecalis. The study design included a distal colonic resection and anastomosis followed by introduction of E. faecalis to anastomotic tissues via enema. Mice were assigned randomly to receive either ABA-PEG20-Pi20 or its unphosphorylated precursor ABA-PEG20k in their drinking water. The development of anastomotic leak was determined after the animals had been killed. Overnight incubation of two different E. faecalis collagenolytic strains with 2 mmol/l of ABA-PEG20k-Pi20 led to near complete inhibition of collagenase production (from 21 000 to 1000 and from 68 000 to 5000 units; P < 0·001; 6 samples per group) without suppressing bacterial growth. In mice drinking 1 per cent ABA-PEG20k-Pi20, the phosphate concentration in the distal colonic mucosa increased twofold and leak rates decreased from eight of 15 to three of 15 animals (P < 0·001). In mice drinking ABA-PEG20k-Pi20, the percentage of collagenolytic colonies among E. faecalis populations present at anastomotic tissue sites was decreased by 6-4800-fold (P = 0·008; 5 animals). These data indicate that oral intake of ABA-PEG20k-Pi20 may be an effective agent to contain the virulence of E. faecalis and may prevent anastomotic leak caused by this organism. Clinical relevance Progress in understanding the pathogenesis of anastomotic leak continues to point to intestinal bacteria as key causative agents. The presence of pathogens such as Enterococcus faecalis that predominate on anastomotic tissues despite antibiotic use, coupled with their ability to produce collagenase, appears to alter the process of healing that leads to leakage. Further antibiotic administration may seem logical, but carries the unwanted risk of eliminating the normal microbiome, which functions competitively to exclude and suppress the virulence of pathogens such as E. faecalis. Therefore, non-antibiotic strategies that can suppress the production of collagenase by E. faecalis without affecting its growth, or potentially normal beneficial microbiota, may have unique advantages. The findings of this study demonstrate that drinking a phosphate-based polymer can achieve the goal of preventing anastomotic leak by suppressing collagenase production in E. faecalis without affecting its growth. © 2018 BJS Society Ltd Published by John Wiley & Sons Ltd.

Memory--a century of consolidation.

PubMed

McGaugh, J L

2000-01-14

The memory consolidation hypothesis proposed 100 years ago by Müller and Pilzecker continues to guide memory research. The hypothesis that new memories consolidate slowly over time has stimulated studies revealing the hormonal and neural influences regulating memory consolidation, as well as molecular and cellular mechanisms. This review examines the progress made over the century in understanding the time-dependent processes that create our lasting memories.

Clinical and subclinical leaks after low colorectal anastomosis: a clinical and radiologic study.

PubMed

Lim, Michael; Akhtar, Saleem; Sasapu, Kishore; Harris, Keith; Burke, Dermot; Sagar, Peter; Finan, Paul

2006-10-01

This study was designed to examine the natural history of subclinical leaks and their effect on bowel function and quality of life and to evaluate water-soluble contrast enema features that predict anastomotic healing after leaks. Consecutive patients who underwent low rectal anastomosis were followed up postoperatively for leaks. All leaks were confirmed radiologically with CT scanning and water-soluble contrast enema imaging. Water-soluble contrast enemas were serially repeated to identify healing. Characteristics on initial water-soluble contrast enema were correlated with observed healing. Postoperatively, patients were required to fill in a quality of life and a bowel function questionnaire. A total of 138 patients underwent low rectal anastomosis procedures with a median follow-up period of 26 (interquartile range, 19-37) months. There were 23 documented leaks of which 13 (9 percent) presented clinically and 10 (8 percent) presented subclinically. Ileostomy closure was possible in 4 of 13 (30 percent) patients with a clinical leak and all 10 (100 percent) patients with a subclinical leak. Median quality of life scores were lower for patients with clinical leaks and no ileostomy closure (P = 0.03). Bowel function for subclinical leak patients and clinical leak patients with ileostomy closure were similarly impaired. The presence of a cavity (P = 0.01) and a stricture (P = 0.01) at the anastomotic site were unfavorable radiologic features associated with nonhealing. Subclinical leaks are more benign in their natural history compared with clinical leaks. Quality of life and bowel function is no better in patients with a subclinical leak compared with patients with a clinical leak who have ileostomy closure. Anastomotic leaks may resolve if favorable radiologic features are present.

Fibrin glue as agent for sealing corneal and conjunctival wound leaks.

PubMed

Scalcione, C; Ortiz-Vaquerizas, D; Said, D G; Dua, H S

2018-02-01

PurposeTo describe a novel use of fibrin glue in managing leaking blebs and leaking wounds following trauma or surgery.MethodsInterventional case series.ResultsWe report eight patients, including three where intra-operative or immediate post-penetrating keratoplasty recalcitrant leaks from the graft-host junction and/or openings created by the needle pass, were noted. All three had thin recipient beds in the sector of leak. This was managed by intra-cameral injection of fibrin glue in the affected quadrant. This stopped the leak and allowed the defect to heal. One patient of Descemets-stripping-endothelial-keratoplasty had leak from the surgical wound, which was also sealed with fibrin glue. Two patients with leaking glaucoma-surgery-related blebs were treated with intra-bleb injection of fibrin glue to stop the leak. One patient with a penetrating corneal injury with a metal wire had a brisk leak upon removal of the wire. This was sealed with fibrin glue. Another patient of chemical burn with spontaneous leaks was managed by glue injection in the perforations. Transient rise of intraocular pressure in one patient with a leaking bleb was the only adverse event recorded.ConclusionThis novel adaptation of the application of fibrin glue can help to deal with persistent intra-operative, post-operative and traumatic aqueous and air leaks.

Effect of forced exercise and exercise withdrawal on memory, serum and hippocampal corticosterone levels in rats.

PubMed

Radahmadi, Maryam; Alaei, Hojjatallah; Sharifi, Mohammad Reza; Hosseini, Nasrin

2015-10-01

Evidence suggests that there are positive effects of exercise on learning and memory. Moreover, some studies have demonstrated that forced exercise plays the role of a stressor. This study was aimed at investigating the effects of different timing of exercise and exercise withdrawal on memory, and serum and hippocampal corticosterone (CORT) levels. Wistar rats were randomly divided into five groups: control, sham, exercise-rest (exercise withdrawal), rest-exercise (exercised group), and exercise-exercise (continuous exercise). Rats were forced to run on a treadmill for 1 h/day at a speed 20-21-m/min. Memory function was evaluated by the passive avoidance test in different intervals (1, 7 and 21 days) after foot shock. Findings showed that after the exercise withdrawal, short-term and mid-term memories, had significant enhancement compared to the control group, while the long-term memory did not present this result. In addition, the serum and hippocampal CORT levels were at the basal levels after the rest period in the exercise-rest group. In the rest-exercise group, exercise improved mid- and long-term memories, whereas continuous exercise improved all types short-, mid- and long-term memories, particularly the mid-term memory. Twenty-one and forty-two days of exercise significantly decreased the serum and hippocampal CORT levels. It seems that exercise for at least 21 days with no rest could affect biochemical factors in the brain. Also, regular continuous exercise plays an important role in memory function. Hence, the duration and withdraw of exercise are important factors for the neurobiological aspects of the memory responses.

Locating air leaks in manned spacecraft using structure-borne noise.

PubMed

Holland, Stephen D; Chimenti, D E; Roberts, Ron; Strei, Michael

2007-06-01

All manned spacecraft are vulnerable to leaks generated by micrometeorite or debris impacts. Methods for locating such leaks using leak-generated, structure-borne ultrasonic noise are discussed and demonstrated. Cross-correlations of ultrasonic noise waveforms from a leak into vacuum are used to find the location of the leak. Four methods for sensing and processing leak noise have been developed and tested and each of these can be used to reveal the leak location. The methods, based on phased-array, distributed sensor, and dual sensor approaches, utilize the propagation patterns of guided ultrasonic Lamb waves in the spacecraft skin structure to find the source or direction of the leak noise. It is shown that each method can be used to successfully locate the leak to within a few millimeters on a 0.6-m2 aluminum plate. The relative merits of the four methods are discussed.

Endoluminal stenting for the management of leak following sleeve gastrectomy and loop duodenojejunal bypass with sleeve gastrectomy.

PubMed

Tsai, Ying-Nan; Wang, Hsiu-Po; Huang, Chih-Kun; Chang, Po-Chin; Lin, I-Chang; Tai, Chi-Ming

2018-01-01

Postoperative leak is a serious complication of bariatric surgery and often results in significant morbidity and mortality. Stent placement is a less invasive alternative to surgery for the treatment of bariatric surgical leak. We evaluated the efficacy and complications of covered self-expandable metal stents (SEMS) in the treatment of post-bariatric surgical leak. We retrospectively reviewed patients who underwent stent placement for leak after bariatric surgery. Leak was diagnosed by upper gastrointestinal series or was visualized during the endoscopy. We examined the timing of stent placement, size of the leak, stent migration and its complications, total stent treatment duration, and treatment outcome. Between January 2011 and April 2015, seven patients underwent covered SEMS placement for leak after bariatric surgery, including laparoscopic sleeve gastrectomy (LSG) (n = 5) and laparoscopic loop duodenojejunal bypass with sleeve gastrectomy (LDJB-SG) (n = 2). A stent was placed in one patient for infection control and bridging to revisional surgery. Among the other six patients, one patient who received stent placement one year after leak diagnosis failed to achieve leak closure, and five patients with early stent placement achieved leak closure. Three patients with small leak achieved leak closure more quickly. Stent migration was found in six patients, and associated ulcers occurred in five patients. We conclude that stenting is effective in the management of staple-line leaks following LSG and LDJB-SG. Stent migration and associated ulcers are common after stent placement. Early stent removal can be achieved in patients with small leaks. Copyright © 2017. Published by Elsevier Taiwan.

Treatment of air leak in polytrauma patients with blunt chest injury.

PubMed

Halat, Gabriel; Negrin, Lukas L; Chrysou, Konstantina; Hoksch, Beatrix; Schmid, Ralph A; Kocher, Gregor J

2017-09-01

Precise diagnostics and an adequate therapeutic approach are mandatory in the treatment of air leak in polytrauma patients with blunt chest trauma. The aim of this study was to evaluate the incidence, characteristics, and management of air leak following this injury pattern. Data from 110 polytrauma patients was collected retrospectively. Fifty-four patients received initial treatment by chest tube placement for pneumothorax. These patients were classified into two groups, one with severe air leak and one with minor air leak. An evaluation of injury pattern, chest wall injuries in particular, duration of air leak, reason for drainage maintenance in place, hospital length of stay, ICU stay, ventilator duration, type of treatment, and the delay to surgical intervention was performed. Whereas 4 patients showed severe air leak and were subsequently scheduled for timely surgical intervention, the remaining 50 patients only showed minor air leak. Only 7 patients with minor air leak suffered from prolonged air leak (>5days), which spontaneously resolved in all of them after a mean duration of 7.7days (range 6-12days). Absence of a prolonged air leak resulted in a shorter length of stay and a shorter duration of mechanical ventilation, although no statistical significance was observed. Early spontaneous cessation of most minor air leaks as well as early surgical intervention for severe air leak lead to very satisfactory patient outcomes with a relatively short hospital stay in our patients. We therefore advocate early surgery for lacerations of the pulmonary parenchyma resulting in severe air leak, whereas minor air leaks can usually be treated conservatively. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mitigated Transfer Line Leaks that Result in Surface Pools and Spray Leaks into Pits

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

HEY, B.E.

This analysis provides radiological and toxicological consequence calculations for postulated mitigated leaks during transfers of six waste compositions. Leaks in Cleanout Boxes equipped with supplemental covers and leaks in pits are analyzed.

40 CFR 455.40 - Applicability; description of the pesticide formulating, packaging and repackaging subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... equipment; the testing and emergency operation of safety showers and eye washes; storm water; Department of Transportation (DOT) aerosol leak test bath water from non-continuous overflow baths (batch baths) where no cans have burst from the time of the last water change-out; and on-site laboratories from cleaning...

40 CFR 455.40 - Applicability; description of the pesticide formulating, packaging and repackaging subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... equipment; the testing and emergency operation of safety showers and eye washes; storm water; Department of Transportation (DOT) aerosol leak test bath water from non-continuous overflow baths (batch baths) where no cans have burst from the time of the last water change-out; and on-site laboratories from cleaning...

40 CFR 455.40 - Applicability; description of the pesticide formulating, packaging and repackaging subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... equipment; the testing and emergency operation of safety showers and eye washes; storm water; Department of Transportation (DOT) aerosol leak test bath water from non-continuous overflow baths (batch baths) where no cans have burst from the time of the last water change-out; and on-site laboratories from cleaning...

40 CFR 63.11527 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2011 CFR

2011-07-01

... alarm that will sound when an increase in relative PM loadings is detected over the alarm set point... operating a bag leak detection system, if an alarm sounds, conduct visual monitoring of the monovent or... maintain a continuous parameter monitoring system (CPMS) to measure and record the 3-hour average pressure...

40 CFR Table 10 to Subpart Eeee of... - Continuous Compliance With Work Practice Standards

Code of Federal Regulations, 2010 CFR

2010-07-01

... liquids, operate a vapor balancing system. i. Monitoring each potential source of vapor leakage in the... requirements of 40 CFR part 63, subpart TT, UU, or H. i. Carrying out a leak detection and repair program in... relief devices, monitoring each potential source of vapor leakage in the system, including, but not...

40 CFR 63.1033 - Open-ended valves or lines standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Open-ended valves or lines standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 2 Standards § 63.1033 Open-ended... requirements. (1) Each open-ended valve or line shall be equipped with a cap, blind flange, plug, or a second...

40 CFR 63.1014 - Open-ended valves or lines standards.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Open-ended valves or lines standards... (CONTINUED) National Emission Standards for Equipment Leaks-Control Level 1 § 63.1014 Open-ended valves or... requirements. (1) Each open-ended valve or line shall be equipped with a cap, blind flange, plug, or a second...

46 CFR 61.15-10 - Liquefied-petroleum-gas piping for heating and cooking.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Liquefied-petroleum-gas piping for heating and cooking. 61.15-10 Section 61.15-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE... piping for heating and cooking. (a) Leak tests as described in paragraph (b) of this section shall be...

Developmental Changes in Item and Source Memory: Evidence from an ERP Recognition Memory Study with Children, Adolescents, and Adults

ERIC Educational Resources Information Center

Sprondel, Volker; Kipp, Kerstin H.; Mecklinger, Axel

2011-01-01

Event-related potential (ERP) correlates of item and source memory were assessed in 18 children (7-8 years), 20 adolescents (13-14 years), and 20 adults (20-29 years) performing a continuous recognition memory task with object and nonobject stimuli. Memory performance increased with age and was particularly low for source memory in children. The…

Predictive factors for outcomes of patients undergoing endoscopic therapy for bile leak after hepatobiliary surgery.

PubMed

Yabe, Shuntaro; Kato, Hironari; Mizukawa, Sho; Akimoto, Yutaka; Uchida, Daisuke; Seki, Hiroyuki; Tomoda, Takeshi; Matsumoto, Kazuyuki; Yamamoto, Naoki; Horiguchi, Shigeru; Tsutsumi, Koichiro; Okada, Hiroyuki

2017-05-01

Endoscopic procedures are used as first-line treatment for bile leak after hepatobiliary surgery. Advances have been made in endoscopic techniques and devices, but few reports have described the effectiveness of endoscopic procedures and the management principles based on severity of bile leak. We evaluated the effectiveness of an endoscopic procedure for the treatment of bile leak after hepatobiliary surgery. Fifty-eight patients underwent an endoscopic procedure for suspected bile leak after hepatobiliary surgery; the presence of bile leak on endoscopic retrograde cholangiopancreatography (ERCP) was evaluated retrospectively. Two groups were created based on bile leak severity at ERCP. We defined success as follows: technical, successful placement of the plastic stent at the intended bile duct; clinical, improvement in symptoms of bile leak; and eventual, disappearance of bile leak at ERCP. We evaluated several factors that influenced the success of the endoscopic procedure and the differences between bile leak severity. Success rates were as follows: technical, 90%; clinical, 79%; and eventual, 71%. Median interval between first endoscopic procedure and achievement of eventual success was 135 days (IQR, 86-257 days). Bile leak severity was the only independent factor associated with eventual success (P = 0.01). Endoscopic therapy is safe and effective for postoperative bile leak. Bile leak severity is the most important factor influencing successful endoscopic therapy. © 2016 Japan Gastroenterological Endoscopy Society.

Temporal Clustering and Sequencing in Short-Term Memory and Episodic Memory

ERIC Educational Resources Information Center

Farrell, Simon

2012-01-01

A model of short-term memory and episodic memory is presented, with the core assumptions that (a) people parse their continuous experience into episodic clusters and (b) items are clustered together in memory as episodes by binding information within an episode to a common temporal context. Along with the additional assumption that information…

Robotic laser tissue welding of sclera using chitosan films.

PubMed

Garcia, Pablo; Mines, Michael J; Bower, Kraig S; Hill, J; Menon, J; Tremblay, Eric; Smith, Benjamin

2009-01-01

To demonstrate the feasibility of scleral wound closure using a novel adhesive made of chitosan film. Five-millimeter scleral lacerations were created in enucleated pig eyes. Casted chitosan films were sized to 7x7 mm patches. Lacerations were sealed with chitosan film alone (7 eyes) or chitosan film followed by laser irradiation using a near infrared laser (1,455 nm) at 350 mW for 6 minutes (7 eyes). Seven eyes were closed with 9-0 nylon suture for comparison (7 eyes). Outcome measures included watertight closure, closure time, and leak pressure. Leak pressure was measured with a pressure transducer attached to tubing continuously monitored intraocular pressure during saline infusion. Watertight closure testing was performed immediately following closure (n = 3 per group) and after 24 hours (n = 3 per group). One eye in each group was fixed in formalin for histology. All wounds were watertight for each closure method. Mean closure time with unlasered chitosan film was 2.24 minutes (range 1.80-3.26, 7 eyes) with a mean leak pressure of 303 mm Hg (range 217-364, 3 eyes). Mean closure time with lasered chitosan was 12.47 minutes (range 11.45-14.15, 7 eyes) with a mean leak pressure of 454.7 mm Hg (range 152-721, 3 eyes). Suture closure required a mean of 4.83 minutes (range 4.03-7.30, 7 eyes) and resulted in a mean leak pressure of 570.3 mm Hg (range 460-646, 3 eyes). Both lasered and unlasered chitosan eyes remained watertight after 24 hours. Histology revealed minimal laser tissue damage in lasered eyes. In this preliminary study chitosan film successfully closed scleral lacerations with and without the application of laser energy. While laser appears to strengthen the closure, it significantly increases the closure time. Chitosan based adhesives hold promise as a scleral wound closure technique.

The use of self-expanding silicone stents in esophageal cancer care: optimal pre-, peri-, and postoperative care.

PubMed

Martin, Robert; Duvall, Ryan; Ellis, Susan; Scoggins, Charles R

2009-03-01

Preoperative nutritional supplementation, management of esophageal leaks, and postoperative anastomotic strictures still remain common problems in the management of esophageal cancer. Jejunal feeding tubes, total parenteral nutrition (TPN) with nasogastric suction, and repeated esophageal dilations remain the most common treatments, respectively. The aim of this study was to evaluate the use of removable silicone stents in (1) the preoperative nutritional optimization during neoadjuvant therapy, (2) the management of perioperative anastomotic leak, and (3) the management of postoperative anastomotic strictures. Review of our prospectively maintained esophageal database identified 15 patients who had removable self-expanding silicone stents placed in the management of one of these three management problems from July 2004 to August 2006. Preoperative therapy: Five patients underwent initial stent placement in preparation for neoadjuvant therapy. Dysphagia relief was seen in 100% of patients, with optimal caloric needs taken within 24 h of placement. All patients tolerated neoadjuvant therapy without delay from dehydration or malnutrition. One stent migration was found at the time of operation, which was removed without sequelae. Perioperative therapy: Five patients developed delayed (>10 days) esophageal leaks that were managed with removable esophageal stent and percutaneous drainage (in three patients). All patients had successful exclusion of the leak on the day of the procedure with resumption of oral intake on the evening of procedure. All five healed leaks without sequelae. Postoperative therapy: Five patients developed postoperative anastomotic strictures that required dilation and placement of removable esophageal stent. The median number of dilations was 1 (range 1-2), with all stents placed for approximate 3 months duration. All patients had immediate dysphagia relief after stent placement. Removable esophageal stents are novel treatment option to optimize relief of symptoms and return the patients back to a more normal oral intake. Continued evaluation is needed to consider stent use as first-line therapy.

INNOVATIVE ACOUSTIC SENSOR TECHNOLOGIES FOR LEAK DETECTION IN CHALLENGING PIPE TYPES

DTIC Science & Technology

2016-12-30

through focused acoustic surveys that are typically conducted at the correlated location prior to marking the leak location. All three technologies were...shift” survey with cross- correlation Echologics LeakFinderRTT M Field survey of leak signatures. Recommended every 3-5 years Contractor...cross- correlation features to detect and pinpoint leaks in challenging pipe types, as well as metallic pipes. 15. SUBJECT TERMS Leak detection

40 CFR 265.196 - Response to leaks or spills and disposition of leaking or unfit-for-use tank systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Response to leaks or spills and... leaks or spills and disposition of leaking or unfit-for-use tank systems. A tank system or secondary containment system from which there has been a leak or spill, or which is un-fit for use, must be removed from...

Probabilistic pipe fracture evaluations for leak-rate-detection applications

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

Rahman, S.; Ghadiali, N.; Paul, D.

1995-04-01

Regulatory Guide 1.45, {open_quotes}Reactor Coolant Pressure Boundary Leakage Detection Systems,{close_quotes} was published by the U.S. Nuclear Regulatory Commission (NRC) in May 1973, and provides guidance on leak detection methods and system requirements for Light Water Reactors. Additionally, leak detection limits are specified in plant Technical Specifications and are different for Boiling Water Reactors (BWRs) and Pressurized Water Reactors (PWRs). These leak detection limits are also used in leak-before-break evaluations performed in accordance with Draft Standard Review Plan, Section 3.6.3, {open_quotes}Leak Before Break Evaluation Procedures{close_quotes} where a margin of 10 on the leak detection limit is used in determining the crackmore » size considered in subsequent fracture analyses. This study was requested by the NRC to: (1) evaluate the conditional failure probability for BWR and PWR piping for pipes that were leaking at the allowable leak detection limit, and (2) evaluate the margin of 10 to determine if it was unnecessarily large. A probabilistic approach was undertaken to conduct fracture evaluations of circumferentially cracked pipes for leak-rate-detection applications. Sixteen nuclear piping systems in BWR and PWR plants were analyzed to evaluate conditional failure probability and effects of crack-morphology variability on the current margins used in leak rate detection for leak-before-break.« less

Cognitive effects of hormone therapy continuation or discontinuation in a sample of women at risk for Alzheimer’s disease

PubMed Central

Wroolie, Tonita E.; Kenna, Heather A.; Williams, Katherine E.; Rasgon, Natalie L.

2015-01-01

Use of estrogen-based hormone therapy (HT), as a protection from cognitive decline and Alzheimer’s disease, is controversial although cumulative data supports HT use when initiated close to menopause onset with estrogen formulations containing 17β-estradiol (17β-E) being preferable to conjugated equine estrogen formulations. Little is known regarding specific populations of women who may derive benefit from HT. Women with heightened risk for AD (aged 49-69), all of whom were taking HT for at least one year, most of whom initiated HT close to menopause onset, underwent cognitive assessment followed by randomization to continue or discontinue HT. Assessments were repeated at two years after randomization. Women who continued HT performed better on cognitive domains composed of measures of verbal memory, and combined attention, working memory, and processing speed measures. Women who used 17β-E versus conjugated equine estrogen, whether randomized to continue or discontinue HT showed better verbal memory performance at the 2-year follow-up assessment. An interaction was also found with HT randomization and family history of AD in a first degree relative. All women offspring of patients with AD declined in verbal memory however, women who continued HT declined less than women who discontinued HT. Women without a first-degree relative with AD showed verbal memory improvement (likely due to practice effects) with continuance and declined with discontinuance of HT. Continuation of HT use appears to protect cognition in women with heightened risk for AD when initiated close to menopause onset. PMID:26209223

If you watch it move, you'll recognize it in 3D: Transfer of depth cues between encoding and retrieval.

PubMed

Papenmeier, Frank; Schwan, Stephan

2016-02-01

Viewing objects with stereoscopic displays provides additional depth cues through binocular disparity supporting object recognition. So far, it was unknown whether this results from the representation of specific stereoscopic information in memory or a more general representation of an object's depth structure. Therefore, we investigated whether continuous object rotation acting as depth cue during encoding results in a memory representation that can subsequently be accessed by stereoscopic information during retrieval. In Experiment 1, we found such transfer effects from continuous object rotation during encoding to stereoscopic presentations during retrieval. In Experiments 2a and 2b, we found that the continuity of object rotation is important because only continuous rotation and/or stereoscopic depth but not multiple static snapshots presented without stereoscopic information caused the extraction of an object's depth structure into memory. We conclude that an object's depth structure and not specific depth cues are represented in memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Out of sight but not out of mind: the neurophysiology of iconic memory in the superior temporal sulcus.

PubMed

Keysers, C; Xiao, D-K; Foldiak, P; Perrett, D I

2005-05-01

Iconic memory, the short-lasting visual memory of a briefly flashed stimulus, is an important component of most models of visual perception. Here we investigate what physiological mechanisms underlie this capacity by showing rapid serial visual presentation (RSVP) sequences with and without interstimulus gaps to human observers and macaque monkeys. For gaps of up to 93 ms between consecutive images, human observers and neurones in the temporal cortex of macaque monkeys were found to continue processing a stimulus as if it was still present on the screen. The continued firing of neurones in temporal cortex may therefore underlie iconic memory. Based on these findings, a neurophysiological vision of iconic memory is presented.

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

Green, William; Xiong, Chi; Khater, Marwan

Due to the high radiative forcing of methane, fugitive natural gas leaks pose a significant challenge to the near-term environmental viability of oil and gas extraction. Reducing the subsequent environmental impact requires cost-effective sensor nodes for reliable, rapid, and continuous identification of extraneous methane emissions. The efficacy of laser spectroscopy has been widely demonstrated in both environmental and medical applications due to its sensitivity and specificity to the target analyte. However, the present cost and the lack of manufacturing scalability of free-space optical systems can limit their viability for economical wide-area sensor networks in localized leak detection applications. In thismore » paper, we will review the development and performance of a cost-effective silicon photonic sensing platform. This platform uses silicon photonic waveguide and packaging integration technologies to enable on-chip evanescent field spectroscopy of methane.« less

The effect of autologous fibrin tissue adhesive on postoperative cerebrospinal fluid leak in spinal cord surgery: a randomized controlled trial.

PubMed

Nakamura, Hiroshi; Matsuyama, Yukihiro; Yoshihara, Hisatake; Sakai, Yoshihito; Katayama, Yoshito; Nakashima, Shojiro; Takamatsu, Jyunki; Ishiguro, Naoki

2005-07-01

A prospective randomized study evaluating the efficacy of autologous fibrin tissue adhesive for decreasing postoperative cerebrospinal fluid (CSF) leak in spinal cord surgery. To compare postoperative CSF leak in 3 groups (i.e., autologous fibrin tissue adhesive used, commercial fibrin glue used, and no fibrin tissue adhesive used) of patients undergoing spinal surgery who needed dural incision. Spinal cord operations, particularly when dural incision is inevitable, sometimes involve postoperative CSF leak. Because CSF leak is a serious complication, countermeasure is necessary to prevent it after dural suture. Commercial fibrin tissue adhesive was formerly used. Because the possibility of prion infection was widely noticed, commercial fibrin tissue adhesive containing animal components has been used less often. In 13 of 39 cases in which dural incision would be made, 400 mL whole blood was drawn, and autologous fibrin tissue adhesive was made of plasma. Cases were divided into 3 groups: (1) dural closure alone, (2) use of autologous fibrin tissue adhesive after dural closure, and (3) use of commercial fibrin tissue adhesive after dural closure. The primary outcome measure was determined as postoperative (3 days) volume of drainage fluid, and results were analyzed using the analysis of variance. The secondary outcome measure was general blood test, coagulation assay, and plasma fibrinogen, and these were analyzed also using the analysis of variance. There was a significant difference in the primary outcome between the autologous and control groups. No complications such as infection or continuous CSF leak were observed in any case. The mean volume of drainage fluid was 586.2 mL in the group with autologous fibrin tissue adhesive and 1026.1 mL in the group without fibrin tissue adhesive. The volume of drainage fluid was significantly lower in the former group than that in the latter group. There was no statistical difference between the volumes of the group with autologous adhesive and with commercial adhesive (639.2 mL). We used autologous fibrin tissue adhesive as a new sealant after dural closure instead of commercial fibrin tissue adhesive. No definitive CSF leak was observed, and the volume of drainage fluid was significantly lower in the group with autologous fibrin tissue adhesive than that in the group without fibrin tissue adhesive. The use of autologous fibrin tissue adhesive was superior to that of commercial fibrin tissue adhesive in cost.

Psychological Symptoms and Social Functioning Following Repair of Obstetric Fistula in a Low-Income Setting

PubMed Central

Sikkema, Kathleen J.; Watt, Melissa H.; Masenga, Gileard G.; Mosha, Mary V.

2016-01-01

Objectives Obstetric fistula is a maternal injury that causes uncontrollable leaking of urine or stool, and most women who develop it live in poverty in low-income countries. Obstetric fistula is associated with high rates of stigma and psychological morbidity, but there is uncertainty about the impact of surgical treatment on psychological outcomes. The objective of this exploratory study was to examine changes in psychological symptoms following surgical fistula repair, discharge and reintegration home. Methods Women admitted for surgical repair of obstetric fistula were recruited from a Tanzanian hospital serving a rural catchment area. Psychological symptoms and social functioning were assessed prior to surgery. Approximately 3 months after discharge, a data collector visited the patients' homes to repeat psychosocial measures and assess self-reported incontinence. Baseline to follow-up differences were measured with paired t tests controlling for multiple comparisons. Associations between psychological outcomes and leaking were assessed with t tests and Pearson correlations. Results Participants (N = 28) had been living with fistula for an average of 11 years. Baseline psychological distress was high, and decreased significantly at follow-up. Participants who self-reported continued incontinence at follow-up endorsed significantly higher PTSD and depression symptoms than those who reported being cured, and severity of leaking was associated with psychological distress. Conclusions Fistula patients experience improvements in mental health at 3 months after discharge, but these improvements are curtailed when women experience residual leaking. Given the rate of stress incontinence following surgery, it is important to prepare fistula patients for the possibility of incomplete cure and help them develop appropriate coping strategies. PMID:27010550

Time to CUSUM: simplified reporting of outcomes in colorectal surgery.

PubMed

Bowles, Thomas A; Watters, David A

2007-07-01

Surgical audit has added value when outcomes can be compared and individual surgeons receive feedback. It is expected that surgeons compare their results with others in similar local practice, the published work, or peers from a craft group audit. Although feedback and comparison are worthy aims, for many surgeons the standards have not been agreed nor is there a craft group audit. The aim of this paper was to develop a reporting format for surgeons carrying out colorectal surgery in a regional hospital. The performance of 13 individual surgeons was analysed using a comprehensive colorectal audit with more than 600 cases. Feedback included caseload and type. Risk stratification of outcomes included; operation urgency, age and Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity. Outcome measures were anastomotic leaks, end stoma rates, unplanned reoperations and mortality. Visual feedback included cumulative summation graphs for elective leaks, mortality and unplanned reoperations. A single A4 page of an individuals performance could be prepared that allowed comparison to the groups data overall. Alerts were set at 2-5% elective leaks, 4-7.5% mortality and 4-11% unplanned return to theatre. Cumulative summation graphs added to this allowed a visual guide to the key performance indicators. Surgeons need to determine how they will review their individual and collective results. These are equally important to the reported work. Detailed analysis of risk-stratified data should occur. Binary outcomes such as leak, mortality and unplanned reoperations may be followed by cumulative summation graphs. This provides a continually updated method of feedback, enabling immediate visual feedback of a surgeon's performance.

Repeated recall as an intervention to improve memory performance in heart failure patients.

PubMed

Viveiros, Jennifer; Sethares, Kristen; Shapiro, Amy

2017-12-01

Up to 50% of heart failure patients demonstrate aspects of cognitive impairment, including memory deficit. Novel interventions are needed to address memory deficit among heart failure patients. The goal of this study was to evaluate the testing effect as an intervention to improve memory performance in heart failure patients. This was a randomized controlled clinical trial ( N=84) comparing the memory performance of heart failure patients with and without mild cognitive impairment after a repeated testing intervention. Memory performance was measured by verbal word pair associates recall scores, between attention control and experimental subjects. Patients had a mean age of 71.7 ± 13.3 years and similar baseline memory (immediate p=.79 and delayed p=.47). Overall, there were no significant differences in memory between experimental and control subjects, respectively (67.2±18.87 vs. 61.9±22.3, verbal word pair associates, t = -1.179, p=.24). In the final hierarchical regression model, age ( p=.018) and education ( p=.006) were significant predictors of memory performance, with the intervention approaching significance ( p=.079). Although not statistically significant, the intervention group reported better memory. Age and education continue to be significant contributors to memory performance in the heart failure population. Continued development of interventions to improve memory performance in heart failure patients is indicated.

Leak detection by mass balance effective for Norman Wells line

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

Liou, J.C.P.

Mass-balance calculations for leak detection have been shown as effective as a leading software system, in a comparison based on a major Canadian crude-oil pipeline. The calculations and NovaCorp`s Leakstop software each detected 4% (approximately) or greater leaks on Interprovincial Pipe Line (IPL) Inc.`s Norman Wells pipeline. Insufficient data exist to assess performances of the two methods for leaks smaller than 4%. Pipeline leak detection using such software-based systems are common. Their effectiveness is measured by how small and how quickly a leak can be detected. Algorithms used and measurement uncertainties determine leak detectability.

Water conservation study. Badger Army Ammunition Plant, Baraboo, Wisconsin. Final report

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

NONE

1995-05-01

The purpose of this water conservation study is to identify projects which result in energy maintenance and cost savings in the process water distribution system at Badger Army Ammunition Plant (BAAP) in Baraboo, Wisconsin. A leak detection survey was performed on all process water piping with a diameter of 6 inches or greater. The leak detection analysis was performed using a combination of listening devices and preamplified-transducer systems to identify the majority of leak locations. When the location of the leak could not be readily identified using these methods, a leak correlator was used. The leak correlator determines leak locationmore » based on the time it takes for sound to travel from the leak to a waterline connection point.« less

Rapid, Vehicle-Based Identification of Location and Magnitude of Urban Natural Gas Pipeline Leaks.

PubMed

von Fischer, Joseph C; Cooley, Daniel; Chamberlain, Sam; Gaylord, Adam; Griebenow, Claire J; Hamburg, Steven P; Salo, Jessica; Schumacher, Russ; Theobald, David; Ham, Jay

2017-04-04

Information about the location and magnitudes of natural gas (NG) leaks from urban distribution pipelines is important for minimizing greenhouse gas emissions and optimizing investment in pipeline management. To enable rapid collection of such data, we developed a relatively simple method using high-precision methane analyzers in Google Street View cars. Our data indicate that this automated leak survey system can document patterns in leak location and magnitude within and among cities, even without wind data. We found that urban areas with prevalent corrosion-prone distribution lines (Boston, MA, Staten Island, NY, and Syracuse, NY), leaked approximately 25-fold more methane than cities with more modern pipeline materials (Burlington, VT, and Indianapolis, IN). Although this mobile monitoring method produces conservative estimates of leak rates and leak counts, it can still help prioritize both leak repairs and replacement of leak-prone sections of distribution lines, thus minimizing methane emissions over short and long terms.

Improved techniques reduce face mask leak during simulated neonatal resuscitation: study 2.

PubMed

Wood, Fiona E; Morley, Colin J; Dawson, Jennifer A; Kamlin, C Omar F; Owen, Louise S; Donath, Susan; Davis, Peter G

2008-05-01

Techniques of positioning and holding neonatal face masks vary. Studies have shown that leak at the face mask is common and often substantial irrespective of operator experience. (1) To identify a technique for face mask placement and hold which will minimise mask leak. (2) To investigate the effect of written instruction and demonstration of the identified technique on mask leak for two round face masks. Three experienced neonatologists compared methods of placing and holding face masks to minimise the leak for Fisher & Paykel 60 mm and Laerdal size 0/1 masks. 50 clinical staff gave positive pressure ventilation to a modified manikin designed to measure leak at the face mask. They were provided with written instructions on how to position and hold each mask and then received a demonstration. Face mask leak was measured after each teaching intervention. A technique of positioning and holding the face masks was identified which minimised leak. The mean (SD) mask leaks before instruction, after instruction and after demonstration were 55% (31), 49% (30), 33% (26) for the Laerdal mask and 57% (25), 47% (28), 32% (30) for the Fisher & Paykel mask. There was no significant difference in mask leak between the two masks. Written instruction alone reduced leak by 8.8% (CI 1.4% to 16.2%) for either mask; when combined with a demonstration mask leak was reduced by 24.1% (CI 16.4% to 31.8%). Written instruction and demonstration of the identified optimal technique resulted in significantly reduced face mask leak.

Mitochondrial proton and electron leaks.

PubMed

Jastroch, Martin; Divakaruni, Ajit S; Mookerjee, Shona; Treberg, Jason R; Brand, Martin D

2010-01-01

Mitochondrial proton and electron leak have a major impact on mitochondrial coupling efficiency and production of reactive oxygen species. In the first part of this chapter, we address the molecular nature of the basal and inducible proton leak pathways, and their physiological importance. The basal leak is unregulated, and a major proportion can be attributed to mitochondrial anion carriers, whereas the proton leak through the lipid bilayer appears to be minor. The basal proton leak is cell-type specific and correlates with metabolic rate. The inducible leak through the ANT (adenine nucleotide translocase) and UCPs (uncoupling proteins) can be activated by fatty acids, superoxide or lipid peroxidation products. The physiological role of inducible leak through UCP1 in mammalian brown adipose tissue is heat production, whereas the roles of non-mammalian UCP1 and its paralogous proteins, in particular UCP2 and UCP3, are not yet resolved. The second part of the chapter focuses on the electron leak that occurs in the mitochondrial electron transport chain. Exit of electrons prior to the reduction of oxygen to water at cytochrome c oxidase causes superoxide production. As the mechanisms of electron leak are crucial to understanding their physiological relevance, we summarize the mechanisms and topology of electron leak from complexes I and III in studies using isolated mitochondria. We also highlight recent progress and challenges of assessing electron leak in the living cell. Finally, we emphasize the importance of proton and electron leak as therapeutic targets in body mass regulation and insulin secretion.

An integrated development workflow for community-driven FOSS-projects using continuous integration tools

NASA Astrophysics Data System (ADS)

Bilke, Lars; Watanabe, Norihiro; Naumov, Dmitri; Kolditz, Olaf

2016-04-01

A complex software project in general with high standards regarding code quality requires automated tools to help developers in doing repetitive and tedious tasks such as compilation on different platforms and configurations, doing unit testing as well as end-to-end tests and generating distributable binaries and documentation. This is known as continuous integration (CI). A community-driven FOSS-project within the Earth Sciences benefits even more from CI as time and resources regarding software development are often limited. Therefore testing developed code on more than the developers PC is a task which is often neglected and where CI can be the solution. We developed an integrated workflow based on GitHub, Travis and Jenkins for the community project OpenGeoSys - a coupled multiphysics modeling and simulation package - allowing developers to concentrate on implementing new features in a tight feedback loop. Every interested developer/user can create a pull request containing source code modifications on the online collaboration platform GitHub. The modifications are checked (compilation, compiler warnings, memory leaks, undefined behaviors, unit tests, end-to-end tests, analyzing differences in simulation run results between changes etc.) from the CI system which automatically responds to the pull request or by email on success or failure with detailed reports eventually requesting to improve the modifications. Core team developers review the modifications and merge them into the main development line once they satisfy agreed standards. We aim for efficient data structures and algorithms, self-explaining code, comprehensive documentation and high test code coverage. This workflow keeps entry barriers to get involved into the project low and permits an agile development process concentrating on feature additions rather than software maintenance procedures.

Incidence, risk factors and clinical implications of chyle leak after pancreatic surgery.

PubMed

Strobel, O; Brangs, S; Hinz, U; Pausch, T; Hüttner, F J; Diener, M K; Schneider, L; Hackert, T; Büchler, M W

2017-01-01

Chyle leak is a well known but poorly characterized complication after pancreatic surgery. Available data on incidence, risk factors and clinical significance of chyle leak are highly heterogeneous. For this cohort study all patients who underwent pancreatic surgery between January 2008 and December 2012 were identified from a prospective database. Chyle leak was defined as any drainage output with triglyceride content of 110 mg/dl or more. Risk factors for chyle leak were assessed by univariable and multivariable analyses. The clinical relevance of chyle leak was evaluated using hospital stay and resolution by 14 days for short-term outcome and overall survival for long-term outcome. Chyle leak developed in 346 (10·4 per cent) of 3324 patients. Pre-existing diabetes, resection for malignancy, distal pancreatectomy, duration of surgery 180 min or longer, and concomitant pancreatic fistula or abscess were independent risk factors for chyle leak. Both isolated chyle leak and coincidental chyle leak (with other intra-abdominal complications) were associated with prolonged hospital stay. Some 178 (87·7 per cent) of 203 isolated chyle leaks and 90 (70·3 per cent) of 128 coincidental chyle leaks resolved with conservative management within 14 days. Initial and maximum drainage volumes were associated with duration of hospital stay and success of therapy by 14 days. Impact on survival was restricted to chyle leaks that persisted at 14 days in patients with cancer undergoing palliative surgery. Chyle leak is a relevant complication, with an incidence of more than 10 per cent after pancreatic surgery, and has a major impact on hospital stay. Drainage volume is associated with hospital stay and success of therapy. © 2016 BJS Society Ltd Published by John Wiley & Sons Ltd.

Routine intraoperative leak testing for sleeve gastrectomy: is the leak test full of hot air?

PubMed

Bingham, Jason; Lallemand, Michael; Barron, Morgan; Kuckelman, John; Carter, Preston; Blair, Kelly; Martin, Matthew

2016-05-01

Staple line leak after sleeve gastrectomy (SG) is a rare but dreaded complication with a reported incidence of 0% to 8%. Many surgeons routinely test the staple line with an intraoperative leak test (IOLT), but there is little evidence to validate this practice. In fact, there is a theoretical concern that the leak test may weaken the staple line and increase the risk of a postop leak. Retrospective review of all SGs performed over a 7-year period was conducted. Cases were grouped by whether an IOLT was performed, and compared for the incidence of postop staple line leaks. The ability of the IOLT for identifying a staple line defect and for predicting a postoperative leak was analyzed. Five hundred forty-two SGs were performed between 2007 and 2014. Thirteen patients (2.4%) developed a postop staple line leak. The majority of patients (n = 494, 91%) received an IOLT, including all 13 patients (100%) who developed a subsequent clinical leak. There were no (0%) positive IOLTs and no additional interventions were performed based on the IOLT. The IOLT sensitivity and positive predictive value were both 0%. There was a trend, although not significant, to increase leak rates when a routine IOLT was performed vs no routine IOLT (2.6% vs 0%, P = .6). The performance of routine IOLT after SG provided no actionable information, and was negative in all patients who developed a postoperative leak. The routine use of an IOLT did not reduce the incidence of postop leak, and in fact was associated with a higher leak rate after SG. Published by Elsevier Inc.

40 CFR 60.5200 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2011 CFR

2011-07-01

... the flow sensor and other necessary equipment in a position that provides a representative flow. (2) Use a flow sensor with a measurement sensitivity of no greater than 2 percent of the expected process... sensor(s) in a position that provides a representative measurement of the pressure (e.g., particulate...

40 CFR Table 3 to Subpart IIIii of... - Work Practice Standards-Required Actions for Liquid Mercury Spills and Accumulations and Hydrogen...

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Mercury Emissions From Mercury Cell... that you cannot repair the leaking equipment without taking the cell off line, provided that you contain the dripping mercury at all times as described above, and take the cell off line as soon as...

Retrograde air escape via the nasolacrimal system: a previously unrecognized complication of continuous positive airway pressure in the management of obstructive sleep apnea.

PubMed

Singh, Narinder Pal; Walker, Robbie James Eades; Cowan, Fiona; Davidson, Arthur Craig; Roberts, David Newton

2014-05-01

Continuous positive airway pressure (CPAP) is the gold standard treatment for moderate to severe obstructive sleep apnoea (OSA). Eye-related side effects of CPAP are commonly attributed to a poorly sealed mask, allowing leaked air to blow over the eye. We present 3 cases where attended polysomnography (A-PSG) demonstrated CPAP-associated retrograde air escape via the nasolacrimal system (CRANS) in the absence of any mask leaks. Symptoms included dry eye, epiphora, air escape from the medial canthus, and eyelid flutter. Symptoms were controlled with a variety of surgical and nonsurgical techniques. CRANS represents a previously undescribed clinical entity. CRANS may be responsible for some CPAP-related eye side effects and possibly for rarer secondary eye complications, including conjunctivitis and corneal ulceration. CRANS should be suspected in any patient on CPAP complaining of eye symptoms. CRANS may be diagnosed through careful observation during A-PSG and confirmed by performing a "saline bubble test." Management options include nonsurgical (mask alternatives, humidification, nasopharyngeal airway) and surgical techniques (nasal airway surgery, inferior turbinate out-fracture and adhesion, injection of bulking agent around Hasner's valve).

New technique to prevent prolonged air leak: use of 'Tachosuture' technique.

PubMed

Nishida, Tatsuya; Mikami, Iwao; Fujii, Yoshitaka

2017-02-01

Prolonged air leak (defined as air leak >7 days), caused by pulmonary resection or alveolar-pleural fistula, increases postoperative morbidity, prolongs hospital stay and increases healthcare costs. We describe a new technique ('Tachosuture' technique) to prevent prolonged air leak. The key point of this new technique is that air leak is classified into three types and an absorbable suture is added to a TachoSil ® patch in each type to prevent detachment from the lung parenchyma. Between August 2013 and March 2016, 40 patients underwent thoracoscopic surgery using 'Tachosuture' technique. Postoperative air leak always stopped within 3 days (95% confidence interval for the absence of prolonged air leak: 92.5-100%). It is considered that this simple technique is useful to prevent prolonged air leak.

Recollection is a continuous process: implications for dual-process theories of recognition memory.

PubMed

Mickes, Laura; Wais, Peter E; Wixted, John T

2009-04-01

Dual-process theory, which holds that recognition decisions can be based on recollection or familiarity, has long seemed incompatible with signal detection theory, which holds that recognition decisions are based on a singular, continuous memory-strength variable. Formal dual-process models typically regard familiarity as a continuous process (i.e., familiarity comes in degrees), but they construe recollection as a categorical process (i.e., recollection either occurs or does not occur). A continuous process is characterized by a graded relationship between confidence and accuracy, whereas a categorical process is characterized by a binary relationship such that high confidence is associated with high accuracy but all lower degrees of confidence are associated with chance accuracy. Using a source-memory procedure, we found that the relationship between confidence and source-recollection accuracy was graded. Because recollection, like familiarity, is a continuous process, dual-process theory is more compatible with signal detection theory than previously thought.

Prospective Memory and Task Interference in a Continuous Monitoring Dynamic Display Task

ERIC Educational Resources Information Center

Loft, Shayne; Remington, Roger W.

2010-01-01

Theories and methods from the prospective memory literature were used to anticipate how individuals would maintain and retrieve intentions in a continuous monitoring dynamic display task. Participants accepted aircraft into sectors and detected aircraft conflicts during an air traffic control simulation. They were sometimes required to substitute…

A dual-trace model for visual sensory memory.

PubMed

Cappiello, Marcus; Zhang, Weiwei

2016-11-01

Visual sensory memory refers to a transient memory lingering briefly after the stimulus offset. Although previous literature suggests that visual sensory memory is supported by a fine-grained trace for continuous representation and a coarse-grained trace of categorical information, simultaneous separation and assessment of these traces can be difficult without a quantitative model. The present study used a continuous estimation procedure to test a novel mathematical model of the dual-trace hypothesis of visual sensory memory according to which visual sensory memory could be modeled as a mixture of 2 von Mises (2VM) distributions differing in standard deviation. When visual sensory memory and working memory (WM) for colors were distinguished using different experimental manipulations in the first 3 experiments, the 2VM model outperformed Zhang and Luck (2008) standard mixture model (SM) representing a mixture of a single memory trace and random guesses, even though SM outperformed 2VM for WM. Experiment 4 generalized 2VM's advantages of fitting visual sensory memory data over SM from color to orientation. Furthermore, a single trace model and 4 other alternative models were ruled out, suggesting the necessity and sufficiency of dual traces for visual sensory memory. Together these results support the dual-trace model of visual sensory memory and provide a preliminary inquiry into the nature of information loss from visual sensory memory to WM. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Feature bindings endure without attention: evidence from an explicit recall task.

PubMed

Gajewski, Daniel A; Brockmole, James R

2006-08-01

Are integrated objects the unit of capacity of visual working memory, or is continued attention needed to maintain bindings between independently stored features? In a delayed recall task, participants reported the color and shape of a probed item from a memory array. During the delay, attention was manipulated with an exogenous cue. Recall was elevated at validly cued positions, indicating that the cue affected item memory. On invalid trials, participants most frequently recalled either both features (perfect object memory) or neither of the two features (no object memory); the frequency with which only one feature was recalled was significantly lower than predicted by feature independence as determined in a single-feature recall task. These data do not support the view that features are remembered independently when attention is withdrawn. Instead, integrated objects are stored in visual working memory without need for continued attention.

40 CFR 86.1337-96 - Engine dynamometer test run.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., dynamometer, and sampling system. (iii) Change filters, etc., and leak check as necessary. For a single... sample is lost. A separate leak check is needed. A leak check of a filter assembly that has only one seal ring in contact with the filter media will not detect a leak when tested under vacuum. A pressure leak...

40 CFR 86.1337-96 - Engine dynamometer test run.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., dynamometer, and sampling system. (iii) Change filters, etc., and leak check as necessary. For a single... sample is lost. A separate leak check is needed. A leak check of a filter assembly that has only one seal ring in contact with the filter media will not detect a leak when tested under vacuum. A pressure leak...

40 CFR 86.1337-96 - Engine dynamometer test run.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., dynamometer, and sampling system. (iii) Change filters, etc., and leak check as necessary. For a single... sample is lost. A separate leak check is needed. A leak check of a filter assembly that has only one seal ring in contact with the filter media will not detect a leak when tested under vacuum. A pressure leak...

40 CFR 86.1337-96 - Engine dynamometer test run.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., dynamometer, and sampling system. (iii) Change filters, etc., and leak check as necessary. For a single... sample is lost. A separate leak check is needed. A leak check of a filter assembly that has only one seal ring in contact with the filter media will not detect a leak when tested under vacuum. A pressure leak...

Control of Interference during Working Memory Updating

ERIC Educational Resources Information Center

Szmalec, Arnaud; Verbruggen, Frederick; Vandierendonck, Andre; Kemps, Eva

2011-01-01

The current study examined the nature of the processes underlying working memory updating. In 4 experiments using the n-back paradigm, the authors demonstrate that continuous updating of items in working memory prevents strong binding of those items to their contexts in working memory, and hence leads to an increased susceptibility to proactive…

Preventive and therapeutic effect of treadmill running on chronic stress-induced memory deficit in rats.

PubMed

Radahmadi, Maryam; Alaei, Hojjatallah; Sharifi, Mohammad Reza; Hosseini, Nasrin

2015-04-01

Previous results indicated that stress impairs learning and memory. In this research, the effects of preventive, therapeutic and regular continually running activity on chronic stress-induced memory deficit in rats were investigated. 70 male rats were randomly divided into seven groups as follows: Control, Sham, Stress-Rest, Rest-Stress, Stress-Exercise, Exercise-Stress and Exercise-Stress & Exercise groups. Chronic restraint stress was applied 6 h/day for 21days and treadmill running 1 h/day. Memory function was evaluated by the passive avoidance test. The results revealed that running activities had therapeutic effect on mid and long-term memory deficit and preventive effects on short and mid-term memory deficit in stressed rats. Regular continually running activity improved mid and long-term memory compared to Exercise-Stress group. The beneficial effects of exercise were time-dependent in stress conditions. Finally, data corresponded to the possibility that treadmill running had a more important role on treatment rather than on prevention on memory impairment induced by stress. Copyright © 2014 Elsevier Ltd. All rights reserved.

Development of a leak location system for use on underground electric power transmission cable

NASA Astrophysics Data System (ADS)

Williams, J. A.

1982-10-01

This report describes a study to evaluate methods for locating leaks of dielectric fluid from buried high voltage cable systems. Two primary types of leak location systems were investigated: (1) systems that will rapidly isolate the leak within a manhole section, typically 1000 m long on a feeder that might be 30 km long; and (2) systems that will then pinpoint the location of the leak. Rapid leak isolation was accomplished by developing an enhanced conductivity oil probe which allows the injection of a small quantity of conductive oil and which indicates the path of the oil as it drifts downstream in the direction of the leak. Two methods for pinpointing the leak were proven. The more successful method was the use of trained leak location dogs which were found to have far better sensitivity than instruments and which could detect cable oil alone without the need for additives. A tracer gas injection and detection scheme was developed for use in areas where the dogs may be unsuitable.

Endotracheal tube leak pressure and tracheal lumen size in swine.

PubMed

Finholt, D A; Audenaert, S M; Stirt, J A; Marcella, K L; Frierson, H F; Suddarth, L T; Raphaely, R C

1986-06-01

Endotracheal tube "leak" is often estimated in children to judge the fit of uncuffed endotracheal tubes within the trachea. Twenty-five swine were intubated with uncuffed tracheal tubes to determine whether a more sensitive measurement of leaks could be devised and whether leak pressure estimates fit between tracheal tube and trachea. We compared leak pressure measurement using a stethoscope and aneroid manometer with a technique using a microphone, pressure transducer, and recorder, and found no differences between the two methods. The tracheas were then removed and slides prepared of tracheal cross-sectional specimens. Regression analysis revealed a linear relationship between tracheal lumen size and tracheal tube size for both low leak pressure (y = -0.4 + 0.79x, r = 0.88, P less than 0.05) and high leak pressure (y = -2.9 + 0.71x, r = 0.92, P less than 0.05) groups. We conclude that leak testing with a stethoscope and aneroid manometer is sensitive and accurate, and that tracheal tube leak pressure accurately portrays fit between tube and trachea.

Cognitive Effects of Hormone Therapy Continuation or Discontinuation in a Sample of Women at Risk for Alzheimer Disease.

PubMed

Wroolie, Tonita E; Kenna, Heather A; Williams, Katherine E; Rasgon, Natalie L

2015-11-01

Use of estrogen-based hormone therapy (HT) as a protection from cognitive decline and Alzheimer disease (AD) is controversial, although cumulative data support HT use when initiated close to menopause onset with estrogen formulations containing 17β-estradiol preferable to conjugated equine estrogen formulations. Little is known regarding specific populations of women who may derive benefit from HT. Women with heightened risk for AD (aged 49-69), all of whom were taking HT for at least 1 year and most of whom initiated HT close to menopause onset, underwent cognitive assessment followed by randomization to continue or discontinue HT. Assessments were repeated at 2 years after randomization. Women who continued HT performed better on cognitive domains composed of measures of verbal memory and combined attention, working memory, and processing speed measures. Women who used 17β-estradiol versus conjugated equine estrogen, whether randomized to continue or discontinue HT, showed better verbal memory performance at the 2-year follow-up assessment. An interaction was also found with HT randomization and family history of AD in a first-degree relative. All female offspring of patients with AD declined in verbal memory; however, women who continued HT declined less than women who discontinued HT. Women without a first-degree relative with AD showed verbal memory improvement (likely because of practice effects) with continuance and declined with discontinuance of HT. Continuation of HT use appears to protect cognition in women with heightened risk for AD when initiated close to menopause onset. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

Event Boundaries Trigger Rapid Memory Reinstatement of the Prior Events to Promote Their Representation in Long-Term Memory.

PubMed

Sols, Ignasi; DuBrow, Sarah; Davachi, Lila; Fuentemilla, Lluís

2017-11-20

Although everyday experiences unfold continuously over time, shifts in context, or event boundaries, can influence how those events come to be represented in memory [1-4]. Specifically, mnemonic binding across sequential representations is more challenging at context shifts, such that successful temporal associations are more likely to be formed within than across contexts [1, 2, 5-9]. However, in order to preserve a subjective sense of continuity, it is important that the memory system bridge temporally adjacent events, even if they occur in seemingly distinct contexts. Here, we used pattern similarity analysis to scalp electroencephalographic (EEG) recordings during a sequential learning task [2, 3] in humans and showed that the detection of event boundaries triggered a rapid memory reinstatement of the just-encoded sequence episode. Memory reactivation was detected rapidly (∼200-800 ms from the onset of the event boundary) and was specific to context shifts that were preceded by an event sequence with episodic content. Memory reinstatement was not observed during the sequential encoding of events within an episode, indicating that memory reactivation was induced specifically upon context shifts. Finally, the degree of neural similarity between neural responses elicited during sequence encoding and at event boundaries correlated positively with participants' ability to later link across sequences of events, suggesting a critical role in binding temporally adjacent events in long-term memory. Current results shed light onto the neural mechanisms that promote episodic encoding not only for information within the event, but also, importantly, in the ability to link across events to create a memory representation of continuous experience. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Demonstration of a Robotic External Leak Locator on the International Space Station

NASA Technical Reports Server (NTRS)

Naids, Adam; Rossetti, Dino; Bond, Tim; Johnson, Brien; Huang, Alvin; Deal, Alexandra; Fox, Katie; Heiser, Michael; Hartman, William; Mikatarian, Ronald

2017-01-01

The International Space Station (ISS) and all currently conceivable future manned spacecraft are susceptible to mission impacts due to fluid/gas leaks to the exterior environment. For example, there is a well-known risk of ammonia leaks from the ISS External Thermal Control System loops and currently no method to locate them. It was, therefore, critical to develop a method for detecting and locating leaks to preserve vehicle health. The Robotic External Leak Locator (RELL) was developed and deployed to the ISS to provide this capability. An on-orbit validation and demonstration was successfully completed in December 2016 and leak locating operations occurred in February 2017. This paper discusses the results of those exercises including measurements of the environment around ISS, detection of the small ammonia leak and implementation of leak locating methodologies.

Does the usage of digital chest drainage systems reduce pleural inflammation and volume of pleural effusion following oncologic pulmonary resection?-A prospective randomized trial.

PubMed

De Waele, Michèle; Agzarian, John; Hanna, Waël C; Schieman, Colin; Finley, Christian J; Macri, Joseph; Schneider, Laura; Schnurr, Terri; Farrokhyar, Forough; Radford, Katherine; Nair, Parameswaran; Shargall, Yaron

2017-06-01

Prolonged air leak and high-volume pleural drainage are the most common causes for delays in chest tube removal following lung resection. While digital pleural drainage systems have been successfully used in the management of post-operative air leak, their effect on pleural drainage and inflammation has not been studied before. We hypothesized that digital drainage systems (as compared to traditional analog continuous suction), using intermittent balanced suction, are associated with decreased pleural inflammation and postoperative drainage volumes, thus leading to earlier chest tube removal. One hundred and three [103] patients were enrolled and randomized to either analog (n=50) or digital (n=53) drainage systems following oncologic lung resection. Chest tubes were removed according to standardized, pre-defined protocol. Inflammatory mediators [interleukin-1B (IL-1B), 6, 8, tumour necrosis factor-alpha (TNF-α)] in pleural fluid and serum were measured and analysed. The primary outcome of interest was the difference in total volume of postoperative fluid drainage. Secondary outcome measures included duration of chest tube in-situ, prolonged air-leak incidence, length of hospital stay and the correlation between pleural effusion formation, degree of inflammation and type of drainage system used. There was no significant difference in total amount of fluid drained or length of hospital stay between the two groups. A trend for shorter chest tube duration was found with the digital system when compared to the analog (P=0.055). Comparison of inflammatory mediator levels revealed no significant differences between digital and analog drainage systems. The incidence of prolonged post-operative air leak was significantly higher when using the analog system (9 versus 2 patients; P=0.025). Lobectomy was associated with longer chest tube duration (P=0.001) and increased fluid drainage when compared to sub-lobar resection (P<0.001), regardless of drainage system. Use of post-lung resection digital drainage does not appear to decrease pleural fluid formation, but is associated with decreased prolonged air leaks. Total pleural effusion volumes did not differ with the type of drainage system used. These findings support previously established benefits of the digital system in decreasing prolonged air leaks, but the advantages do not appear to extend to decreased pleural fluid formation.

45 CFR 2490.170 - Compliance procedures.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP... THE JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION § 2490.170 Compliance procedures. (a) Except as... for coordinating implementation of this section. Complaints may be sent to James Madison Memorial...

45 CFR 2490.170 - Compliance procedures.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP... THE JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION § 2490.170 Compliance procedures. (a) Except as... for coordinating implementation of this section. Complaints may be sent to James Madison Memorial...

45 CFR 2490.170 - Compliance procedures.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP... THE JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION § 2490.170 Compliance procedures. (a) Except as... for coordinating implementation of this section. Complaints may be sent to James Madison Memorial...

45 CFR 2490.170 - Compliance procedures.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP... THE JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION § 2490.170 Compliance procedures. (a) Except as... for coordinating implementation of this section. Complaints may be sent to James Madison Memorial...

45 CFR 2490.170 - Compliance procedures.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Public Welfare Regulations Relating to Public Welfare (Continued) JAMES MADISON MEMORIAL FELLOWSHIP... THE JAMES MADISON MEMORIAL FELLOWSHIP FOUNDATION § 2490.170 Compliance procedures. (a) Except as... for coordinating implementation of this section. Complaints may be sent to James Madison Memorial...

40 CFR 63.1184 - What do I need to know about the design specifications, installation, and operation of a bag leak...

Code of Federal Regulations, 2010 CFR

2010-07-01

... design specifications, installation, and operation of a bag leak detection system? 63.1184 Section 63... bag leak detection system? A bag leak detection system must meet the following requirements: (a) The bag leak detection system must be certified by the manufacturer to be capable of detecting PM...

Detection of Leaks in Water Distribution System using Non-Destructive Techniques

NASA Astrophysics Data System (ADS)

Aslam, H.; Kaur, M.; Sasi, S.; Mortula, Md M.; Yehia, S.; Ali, T.

2018-05-01

Water is scarce and needs to be conserved. A considerable amount of water which flows in the water distribution systems was found to be lost due to pipe leaks. Consequently, innovations in methods of pipe leakage detections for early recognition and repair of these leaks is vital to ensure minimum wastage of water in distribution systems. A major component of detection of pipe leaks is the ability to accurately locate the leak location in pipes through minimum invasion. Therefore, this paper studies the leak detection abilities of the three NDT’s: Ground Penetration Radar (GPR) and spectrometer and aims at determining whether these instruments are effective in identifying the leak. An experimental setup was constructed to simulate the underground conditions of water distribution systems. After analysing the experimental data, it was concluded that both the GPR and the spectrometer were effective in detecting leaks in the pipes. However, the results obtained from the spectrometer were not very differentiating in terms of observing the leaks in comparison to the results obtained from the GPR. In addition to this, it was concluded that both instruments could not be used if the water from the leaks had reached on the surface, resulting in surface ponding.

Categorical Working Memory Representations are used in Delayed Estimation of Continuous Colors

PubMed Central

Hardman, Kyle O; Vergauwe, Evie; Ricker, Timothy J

2016-01-01

In the last decade, major strides have been made in understanding visual working memory through mathematical modeling of color production responses. In the delayed color estimation task (Wilken & Ma, 2004), participants are given a set of colored squares to remember and a few seconds later asked to reproduce those colors by clicking on a color wheel. The degree of error in these responses is characterized with mathematical models that estimate working memory precision and the proportion of items remembered by participants. A standard mathematical model of color memory assumes that items maintained in memory are remembered through memory for precise details about the particular studied shade of color. We contend that this model is incomplete in its present form because no mechanism is provided for remembering the coarse category of a studied color. In the present work we remedy this omission and present a model of visual working memory that includes both continuous and categorical memory representations. In two experiments we show that our new model outperforms this standard modeling approach, which demonstrates that categorical representations should be accounted for by mathematical models of visual working memory. PMID:27797548

Memory Effects on Movement Behavior in Animal Foraging

PubMed Central

Bracis, Chloe; Gurarie, Eliezer; Van Moorter, Bram; Goodwin, R. Andrew

2015-01-01

An individual’s choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk). We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems. PMID:26288228

Memory Effects on Movement Behavior in Animal Foraging.

PubMed

Bracis, Chloe; Gurarie, Eliezer; Van Moorter, Bram; Goodwin, R Andrew

2015-01-01

An individual's choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk). We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems.

Categorical working memory representations are used in delayed estimation of continuous colors.

PubMed

Hardman, Kyle O; Vergauwe, Evie; Ricker, Timothy J

2017-01-01

In the last decade, major strides have been made in understanding visual working memory through mathematical modeling of color production responses. In the delayed color estimation task (Wilken & Ma, 2004), participants are given a set of colored squares to remember, and a few seconds later asked to reproduce those colors by clicking on a color wheel. The degree of error in these responses is characterized with mathematical models that estimate working memory precision and the proportion of items remembered by participants. A standard mathematical model of color memory assumes that items maintained in memory are remembered through memory for precise details about the particular studied shade of color. We contend that this model is incomplete in its present form because no mechanism is provided for remembering the coarse category of a studied color. In the present work, we remedy this omission and present a model of visual working memory that includes both continuous and categorical memory representations. In 2 experiments, we show that our new model outperforms this standard modeling approach, which demonstrates that categorical representations should be accounted for by mathematical models of visual working memory. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Frameworking memory and serotonergic markers.

PubMed

Meneses, Alfredo

2017-07-26

The evidence for neural markers and memory is continuously being revised, and as evidence continues to accumulate, herein, we frame earlier and new evidence. Hence, in this work, the aim is to provide an appropriate conceptual framework of serotonergic markers associated with neural activity and memory. Serotonin (5-hydroxytryptamine [5-HT]) has multiple pharmacological tools, well-characterized downstream signaling in mammals' species, and established 5-HT neural markers showing new insights about memory functions and dysfunctions, including receptors (5-HT1A/1B/1D, 5-HT2A/2B/2C, and 5-HT3-7), transporter (serotonin transporter [SERT]) and volume transmission present in brain areas involved in memory. Bidirectional influence occurs between 5-HT markers and memory/amnesia. A growing number of researchers report that memory, amnesia, or forgetting modifies neural markers. Diverse approaches support the translatability of using neural markers and cerebral functions/dysfunctions, including memory formation and amnesia. At least, 5-HT1A, 5-HT4, 5-HT6, and 5-HT7 receptors and SERT seem to be useful neural markers and therapeutic targets. Hence, several mechanisms cooperate to achieve synaptic plasticity or memory, including changes in the expression of neurotransmitter receptors and transporters.

Percutaneous management of postoperative bile leaks with an ethylene vinyl alcohol copolymer (Onyx).

PubMed

Uller, W; Müller-Wille, R; Loss, M; Hammer, S; Schleder, S; Goessmann, H; Wiggermann, P; Stroszczynski, C; Wohlgemuth, W A

2013-12-01

The management of postoperative bile leakage is challenging especially if the leak rises from the cut surface of the liver and endoscopic treatment fails. Percutaneous transhepatic treatment of bile leaks with biliary drainage is accepted but often requires long-term placement of the drains and is associated with treatment failures. This series evaluates selective embolization of bile ducts with an ethylene vinyl alcohol copolymer (Onyx) in patients with postoperative bile leaks as an alternative treatment option. Between January and September 2012, five consecutive patients with persistent postoperative bile leaks underwent percutaneous transhepatic Onyx application and were analyzed regarding procedural management, complications and success rates. The persistent bile leaks were situated at the cystic stump (after cholecystectomy, n = 2), at the cut surface of the liver (after extended liver resection, n = 2) and at the surface of the liver after surgical exploration and perihepatic abscess (n = 1). Bile drainage alone (endoscopic or percutaneous) failed in all patients and open redo-surgery was deemed potentially harmful. Bilomas were externally drained in all patients before Onyx application. For the closure of bile leaks, Onyx was injected through a microcatheter in a previously built coil nest to keep Onyx in place. All bile leaks were initially closed immediately. In the 2nd week after Onyx embolization, 2 patients showed recurrent small bile leaks without clinical symptoms. In the 4th week after Onyx application, all leaks were closed. No complications occurred. All leaking bile ducts were initially closed immediately after Onyx application. In the 2nd week after Onyx application, 2 patients showed small bile leaks without clinical symptoms. All leaks were closed in the 4th week after Onyx application. © Georg Thieme Verlag KG Stuttgart · New York.

Anastomotic leak after colorectal resection: A population-based study of risk factors and hospital variation.

PubMed

Nikolian, Vahagn C; Kamdar, Neil S; Regenbogen, Scott E; Morris, Arden M; Byrn, John C; Suwanabol, Pasithorn A; Campbell, Darrell A; Hendren, Samantha

2017-06-01

Anastomotic leak is a major source of morbidity in colorectal operations and has become an area of interest in performance metrics. It is unclear whether anastomotic leak is associated primarily with surgeons' technical performance or explained better by patient characteristics and institutional factors. We sought to establish if anastomotic leak could serve as a valid quality metric in colorectal operations by evaluating provider variation after adjusting for patient factors. We performed a retrospective cohort study of colorectal resection patients in the Michigan Surgical Quality Collaborative. Clinically relevant patient and operative factors were tested for association with anastomotic leak. Hierarchical logistic regression was used to derive risk-adjusted rates of anastomotic leak. Of 9,192 colorectal resections, 244 (2.7%) had a documented anastomotic leak. The incidence of anastomotic leak was 3.0% for patients with pelvic anastomoses and 2.5% for those with intra-abdominal anastomoses. Multivariable analysis showed that a greater operative duration, male sex, body mass index >30 kg/m 2 , tobacco use, chronic immunosuppressive medications, thrombocytosis (platelet count >400 × 10 9 /L), and urgent/emergency operations were independently associated with anastomotic leak (C-statistic = 0.75). After accounting for patient and procedural risk factors, 5 hospitals had a significantly greater incidence of postoperative anastomotic leak. This population-based study shows that risk factors for anastomotic leak include male sex, obesity, tobacco use, immunosuppression, thrombocytosis, greater operative duration, and urgent/emergency operation; models including these factors predict most of the variation in anastomotic leak rates. This study suggests that anastomotic leak can serve as a valid metric that can identify opportunities for quality improvement. Copyright © 2017 Elsevier Inc. All rights reserved.

What is the optimal management of an intra-operative air leak in a colorectal anastomosis?

PubMed

Mitchem, J B; Stafford, C; Francone, T D; Roberts, P L; Schoetz, D J; Marcello, P W; Ricciardi, R

2018-02-01

An airtight anastomosis on intra-operative leak testing has been previously demonstrated to be associated with a lower risk of clinically significant postoperative anastomotic leak following left-sided colorectal anastomosis. However, to date, there is no consistently agreed upon method for management of an intra-operative anastomotic leak. Therefore, we powered a noninferiority study to determine whether suture repair alone was an appropriate strategy for the management of an intra-operative air leak. This is a retrospective cohort analysis of prospectively collected data from a tertiary care referral centre. We included all consecutive patients with left-sided colorectal or ileorectal anastomoses and evidence of air leak during intra-operative leak testing. Patients were excluded if proximal diversion was planned preoperatively, a pre-existing proximal diversion was present at the time of surgery or an anastomosis was ultimately unable to be completed. The primary outcome measure was clinically significant anastomotic leak, as defined by the Surgical Infection Study Group at 30 days. From a sample of 2360 patients, 119 had an intra-operative air leak during leak testing. Sixty-eight patients underwent suture repair alone and 51 underwent proximal diversion or anastomotic reconstruction. The clinically significant leak rate was 9% (6/68; 95% CI: 2-15%) in the suture repair alone arm and 0% (0/51) in the diversion or reconstruction arm. Suture repair alone does not meet the criteria for noninferiority for the management of intra-operative air leak during left-sided colorectal anastomosis. Further repair of intra-operative air leak by suture repair alone should be reconsidered given these findings. Colorectal Disease © 2017 The Association of Coloproctology of Great Britain and Ireland.

Clinical Factors and Postoperative Impact of Bile Leak After Liver Resection.

PubMed

Martin, Allison N; Narayanan, Sowmya; Turrentine, Florence E; Bauer, Todd W; Adams, Reid B; Stukenborg, George J; Zaydfudim, Victor M

2018-04-01

Despite technical advances, bile leak remains a significant complication after hepatectomy. The current study uses a targeted multi-institutional dataset to characterize perioperative factors that are associated with bile leakage after hepatectomy to better understand the impact of bile leak on morbidity and mortality. Adult patients in the 2014-2015 ACS NSQIP targeted hepatectomy dataset were linked to the ACS NSQIP PUF dataset. Bivariable and multivariable regression analyses were used to assess the associations between clinical factors and post-hepatectomy bile leak. Of 6859 patients, 530 (7.7%) had a postoperative bile leak. Proportion of bile leaks was significantly greater in patients after major compared to minor hepatectomy (12.6 vs. 5.1%, p < 0.001). The proportion of patients with bile leak was significantly greater in patients after major hepatectomy who had concomitant enterohepatic reconstruction (31.8 vs. 10.1%, p < 0.001). Postoperative mortality was significantly greater in patients with bile leaks (6.0 vs. 1.7%, p < 0.001). After adjusting for significant covariates, bile leak was independently associated with increased risk of postoperative morbidity (OR = 4.55; 95% CI 3.72-5.56; p < 0.001). After adjusting for significant effects of postoperative complications, liver failure, and reoperation (all p<0.001), bile leak was not independently associated with increased risk of postoperative mortality (p = 0.262). Major hepatectomy and enterohepatic biliary reconstruction are associated with significantly greater rates of bile leak after liver resection. Bile leak is independently associated with significant postoperative morbidity. Mitigation of bile leak is critical in reducing morbidity and mortality after liver resection.

Air-Leak Effects on Ear-Canal Acoustic Absorbance

PubMed Central

Rasetshwane, Daniel M.; Kopun, Judy G.; Gorga, Michael P.; Neely, Stephen T.

2015-01-01

Objective: Accurate ear-canal acoustic measurements, such as wideband acoustic admittance, absorbance, and otoacoustic emissions, require that the measurement probe be tightly sealed in the ear canal. Air leaks can compromise the validity of the measurements, interfere with calibrations, and increase variability. There are no established procedures for determining the presence of air leaks or criteria for what size leak would affect the accuracy of ear-canal acoustic measurements. The purpose of this study was to determine ways to quantify the effects of air leaks and to develop objective criteria to detect their presence. Design: Air leaks were simulated by modifying the foam tips that are used with the measurement probe through insertion of thin plastic tubing. To analyze the effect of air leaks, acoustic measurements were taken with both modified and unmodified foam tips in brass-tube cavities and human ear canals. Measurements were initially made in cavities to determine the range of critical leaks. Subsequently, data were collected in ears of 21 adults with normal hearing and normal middle-ear function. Four acoustic metrics were used for predicting the presence of air leaks and for quantifying these leaks: (1) low-frequency admittance phase (averaged over 0.1–0.2 kHz), (2) low-frequency absorbance, (3) the ratio of compliance volume to physical volume (CV/PV), and (4) the air-leak resonance frequency. The outcome variable in this analysis was the absorbance change (Δabsorbance), which was calculated in eight frequency bands. Results: The trends were similar for both the brass cavities and the ear canals. ΔAbsorbance generally increased with air-leak size and was largest for the lower frequency bands (0.1–0.2 and 0.2–0.5 kHz). Air-leak effects were observed in frequencies up to 10 kHz, but their effects above 1 kHz were unpredictable. These high-frequency air leaks were larger in brass cavities than in ear canals. Each of the four predictor variables exhibited consistent dependence on air-leak size. Low-frequency admittance phase and CV/PV decreased, while low-frequency absorbance and the air-leak resonance frequency increased. Conclusion: The effect of air leaks can be significant when their equivalent diameter exceeds 0.01 in. The observed effects were greatest at low frequencies where air leaks caused absorbance to increase. Recommended criteria for detecting air leaks include the following: when the frequency range of interest extends as low as 0.1 kHz, low-frequency absorbance should be ≤0.20 and low-frequency admittance phase ≥61 degrees. For frequency ranges as low as 0.2 kHz, low-frequency absorbance should be ≤0.29 and low-frequency admittance phase ≥44 degrees. PMID:25170779

Air-leak effects on ear-canal acoustic absorbance.

PubMed

Groon, Katherine A; Rasetshwane, Daniel M; Kopun, Judy G; Gorga, Michael P; Neely, Stephen T

2015-01-01

Accurate ear-canal acoustic measurements, such as wideband acoustic admittance, absorbance, and otoacoustic emissions, require that the measurement probe be tightly sealed in the ear canal. Air leaks can compromise the validity of the measurements, interfere with calibrations, and increase variability. There are no established procedures for determining the presence of air leaks or criteria for what size leak would affect the accuracy of ear-canal acoustic measurements. The purpose of this study was to determine ways to quantify the effects of air leaks and to develop objective criteria to detect their presence. Air leaks were simulated by modifying the foam tips that are used with the measurement probe through insertion of thin plastic tubing. To analyze the effect of air leaks, acoustic measurements were taken with both modified and unmodified foam tips in brass-tube cavities and human ear canals. Measurements were initially made in cavities to determine the range of critical leaks. Subsequently, data were collected in ears of 21 adults with normal hearing and normal middle-ear function. Four acoustic metrics were used for predicting the presence of air leaks and for quantifying these leaks: (1) low-frequency admittance phase (averaged over 0.1-0.2 kHz), (2) low-frequency absorbance, (3) the ratio of compliance volume to physical volume (CV/PV), and (4) the air-leak resonance frequency. The outcome variable in this analysis was the absorbance change (Δabsorbance), which was calculated in eight frequency bands. The trends were similar for both the brass cavities and the ear canals. ΔAbsorbance generally increased with air-leak size and was largest for the lower frequency bands (0.1-0.2 and 0.2-0.5 kHz). Air-leak effects were observed in frequencies up to 10 kHz, but their effects above 1 kHz were unpredictable. These high-frequency air leaks were larger in brass cavities than in ear canals. Each of the four predictor variables exhibited consistent dependence on air-leak size. Low-frequency admittance phase and CV/PV decreased, while low-frequency absorbance and the air-leak resonance frequency increased. The effect of air leaks can be significant when their equivalent diameter exceeds 0.01 in. The observed effects were greatest at low frequencies where air leaks caused absorbance to increase. Recommended criteria for detecting air leaks include the following: when the frequency range of interest extends as low as 0.1 kHz, low-frequency absorbance should be ≤0.20 and low-frequency admittance phase ≥61 degrees. For frequency ranges as low as 0.2 kHz, low-frequency absorbance should be ≤0.29 and low-frequency admittance phase ≥44 degrees.

Fluid pipeline leak detection and location with miniature RF tags

DOEpatents

McIntyre, Timothy J.

2017-05-16

Sensors locate troublesome leaks in pipes or conduits that carry a flowing medium. These sensors, through tailored physical and geometric properties, preferentially seek conduit leaks or breaches due to flow streaming. The sensors can be queried via transceivers outside the conduit or located and interrogated inside by submersible unmanned vehicle to identify and characterize the nature of a leak. The sensors can be functionalized with other capabilities for additional leak and pipeline characterization if needed. Sensors can be recovered from a conduit flow stream and reused for future leak detection activities.

Leak testing and repair of fusion devices

NASA Astrophysics Data System (ADS)

Kozman, T. A.

1983-06-01

The leak testing, reporting and vacuum leak repair techniques of the MPTF yin-yang number one magnet system, the world's largest superconducting magnet system, are discussed. Based on this experience, techniques are developed for testing and repairing leaks on the 42 MPTF-B magnets. The leak hunting techniques for the yin-yang magnet systems were applied to two helium circuits (the coil bundle and guard vacuum; both require helium flow for magnet cooldown). Additionally, during MPTF-B operation there are warm water plasma shields and piping that require leak checking.

Effects of spacing of item repetitions in continuous recognition memory: does item retrieval difficulty promote item retention in older adults?

PubMed

Kılıç, Aslı; Hoyer, William J; Howard, Marc W

2013-01-01

BACKGROUND/STUDY CONTEXT: Older adults exhibit an age-related deficit in item memory as a function of the length of the retention interval, but older adults and young adults usually show roughly equivalent benefits due to the spacing of item repetitions in continuous memory tasks. The current experiment investigates the seemingly paradoxical effects of retention interval and spacing in young and older adults using a continuous recognition memory procedure. Fifty young adults and 52 older adults gave memory confidence ratings to words that were presented once (P1), twice (P2), or three times (P3), and the effects of the lag length and retention interval were assessed at P2 and at P3, respectively. Response times at P2 were disproportionately longer for older adults than for younger adults as a function of the number of items occurring between P1 and P2, suggestive of age-related loss in item memory. Ratings of confidence in memory responses revealed that older adults remembered fewer items at P2 with a high degree of certainty. Confidence ratings given at P3 suggested that young and older adults derived equivalent benefits from the spacing between P1 and P2. Findings of this study support theoretical accounts that suggest that recursive reminding and/or item retrieval difficulty promote item retention in older adults.

Sleeve gastrectomy and the risk of leak: a systematic analysis of 4,888 patients.

PubMed

Aurora, Alexander R; Khaitan, Leena; Saber, Alan A

2012-06-01

Sleeve gastrectomy has become a popular stand-alone bariatric procedure with comparable weight loss and resolution of comorbidities to that of laparoscopic gastric bypass. The simplicity of the procedure and the decreased long-term risk profile make this surgery more appealing. Nonetheless, the ever present risk of a staple-line leak is still of great concern and needs further investigation. An electronic literature search of MEDLINE database plus manual reference checks of articles published on laparoscopic sleeve gastrectomy for morbid obesity and its complications was completed. Keywords used in the search were "sleeve gastrectomy" OR "gastric sleeve" AND "leak." We analyzed 29 publications, including 4,888 patients. We analyzed the frequency of leak after sleeve gastrectomy and its associated risks of causation. The risk of leak after sleeve gastrectomy in all comers was 2.4%. This risk was 2.9% in the super-obese [body mass index (BMI) > 50 kg/m(2)] and 2.2% for BMI < 50 kg/m(2). Staple height and use of buttressing material did not affect leak rate. The use of a size 40-Fr or greater bougie was associated with a leak rate of 0.6% compared with those who used smaller sizes whose leak rate was 2.8%. Leaks were found at the proximal third of the stomach in 89% of cases. Most leaks were diagnosed after discharge. Endoscopic management is a viable option for leaks and was documented in 11% of cases as successful. Sleeve gastrectomy has become an important surgical option for the treatment of the ever growing morbidly obese population. The risk of leak is low at 2.4%. Attention to detail specifically at the esophagogastric junction cannot be stressed enough. Careful patient selection (BMI < 50 kg/m(2)) and adopting the use of a 40-Fr or larger bougie may decrease the risk of leak. Vigilant follow-up during the first 30 days is critical to avoid catastrophe, because most leaks will happen after patient discharge.

Recollection and Familiarity in Recognition Memory: Evidence from ROC Curves

ERIC Educational Resources Information Center

Heathcote, Andrew; Raymond, Frances; Dunn, John

2006-01-01

Does recognition memory rely on discrete recollection, continuous evidence, or both? Is continuous evidence sensitive to only the recency and duration of study (familiarity), or is it also sensitive to details of the study episode? Dual process theories assume recognition is based on recollection and familiarity, with only recollection providing…

Discrete-State and Continuous Models of Recognition Memory: Testing Core Properties under Minimal Assumptions

ERIC Educational Resources Information Center

Kellen, David; Klauer, Karl Christoph

2014-01-01

A classic discussion in the recognition-memory literature concerns the question of whether recognition judgments are better described by continuous or discrete processes. These two hypotheses are instantiated by the signal detection theory model (SDT) and the 2-high-threshold model, respectively. Their comparison has almost invariably relied on…

Beyond ROC Curvature: Strength Effects and Response Time Data Support Continuous-Evidence Models of Recognition Memory

ERIC Educational Resources Information Center

Dube, Chad; Starns, Jeffrey J.; Rotello, Caren M.; Ratcliff, Roger

2012-01-01

A classic question in the recognition memory literature is whether retrieval is best described as a continuous-evidence process consistent with signal detection theory (SDT), or a threshold process consistent with many multinomial processing tree (MPT) models. Because receiver operating characteristics (ROCs) based on confidence ratings are…

Noble Gas Leak Detector for Use in the SNS Neutron Electric Dipole Moment Experiment

NASA Astrophysics Data System (ADS)

Barrow, Chad; Huffman, Paul; Leung, Kent; Korobkina, Ekaterina; White, Christian; nEDM Collaboration Collaboration

2017-09-01

Common practice for leak-checking high vacuum systems uses helium as the probing gas. However, helium may permeate some materials at room temperature, making leak characterization difficult. The experiment to find a permanent electric dipole moment of the neutron (nEDM), to be conducted at Oak Ridge National Laboratories, will employ a large volume of liquid helium housed by such a helium-permeable composite material. It is desirable to construct a leak detector that can employ alternative test gases. The purpose of this experiment is to create a leak detector that can quantify the argon gas flux in a high vacuum environment and interpret this flux as a leak-rate. This apparatus will be used to check the nEDM volumes for leaks at room temperature before cooling down to cryogenic temperatures. Our leak detector uses a residual gas analyzer and a vacuum pumping station to characterize the gas present in an evacuated volume. The introduction of argon gas into the system is interpreted as a leak-rate into the volume. The device has been calibrated with NIST certified calibrated leaks and the machine's sensitivity has been calculated using background gas analysis. As a result of the device construction and software programming, we are able to leak-check composite and polyamide volumes This work was supported in part by the US Department of Energy under Grant No. DE-FG02-97ER41042.

A simple web-based risk calculator (www.anastomoticleak.com) is superior to the surgeon's estimate of anastomotic leak after colon cancer resection.

PubMed

Sammour, T; Lewis, M; Thomas, M L; Lawrence, M J; Hunter, A; Moore, J W

2017-01-01

Anastomotic leak can be a devastating complication, and early prediction is difficult. The aim of this study is to prospectively validate a simple anastomotic leak risk calculator and compare its predictive value with the estimate of the primary operating surgeon. Consecutive patients undergoing elective or emergency colon cancer surgery with a primary anastomosis over a 1-year period were prospectively included. A recently published anastomotic leak risk nomogram was converted to an online calculator ( www.anastomoticleak.com ). The calculator-derived risk of anastomotic leak and the risk estimated by the primary operating surgeon were recorded at the completion of surgery. The primary outcome was anastomotic leak within 90 days as defined by previously published criteria. Area under receiver operating characteristic curve analysis (AUROC) was performed for both risk estimates. A total of 105 patients were screened for inclusion during the study period, of whom 83 met the inclusion criteria. The overall anastomotic leak rate was 9.6%. The anastomotic leak calculator was highly predictive of anastomotic leak (AUROC 0.84, P = 0.002), whereas the surgeon estimate was not predictive (AUROC 0.40, P = 0.243). A simple anastomotic leak risk calculator is significantly better at predicting anastomotic leak than the estimate of the primary surgeon. Further external validation on a larger data set is required.

Memory Transformation Enhances Reinforcement Learning in Dynamic Environments.

PubMed

Santoro, Adam; Frankland, Paul W; Richards, Blake A

2016-11-30

Over the course of systems consolidation, there is a switch from a reliance on detailed episodic memories to generalized schematic memories. This switch is sometimes referred to as "memory transformation." Here we demonstrate a previously unappreciated benefit of memory transformation, namely, its ability to enhance reinforcement learning in a dynamic environment. We developed a neural network that is trained to find rewards in a foraging task where reward locations are continuously changing. The network can use memories for specific locations (episodic memories) and statistical patterns of locations (schematic memories) to guide its search. We find that switching from an episodic to a schematic strategy over time leads to enhanced performance due to the tendency for the reward location to be highly correlated with itself in the short-term, but regress to a stable distribution in the long-term. We also show that the statistics of the environment determine the optimal utilization of both types of memory. Our work recasts the theoretical question of why memory transformation occurs, shifting the focus from the avoidance of memory interference toward the enhancement of reinforcement learning across multiple timescales. As time passes, memories transform from a highly detailed state to a more gist-like state, in a process called "memory transformation." Theories of memory transformation speak to its advantages in terms of reducing memory interference, increasing memory robustness, and building models of the environment. However, the role of memory transformation from the perspective of an agent that continuously acts and receives reward in its environment is not well explored. In this work, we demonstrate a view of memory transformation that defines it as a way of optimizing behavior across multiple timescales. Copyright © 2016 the authors 0270-6474/16/3612228-15$15.00/0.

Leak Detection in Spacecraft Using a 64-Element Multiplexed Passive Array to Monitor Structure-Borne Noise

NASA Astrophysics Data System (ADS)

Holland, Stephen D.; Song, Jun-Ho; Chimenti, D. E.; Roberts, Ron

2006-03-01

We demonstrate an array sensor method intended to locate leaks in manned spacecraft using leak-generated, structure-borne ultrasonic noise. We have developed and tested a method for sensing and processing leak noise to reveal the leak location involving the use of a 64-element phased-array. Cross-correlations of ultrasonic noise waveforms from a leak into vacuum have been used with a phased-array analysis to find the direction from the sensor to the leak. This method measures the propagation of guided ultrasonic Lamb waves passing under the PZT array sensor in the spacecraft skin structure. This paper will describe the custom-designed array with integrated electronics, as well as the performance of the array in prototype applications. We show that this method can be used to successfully locate leaks to within a few millimeters on a 0.6-m square aluminum plate.

Comprehensive Quantitative Analysis on Privacy Leak Behavior

PubMed Central

Fan, Lejun; Wang, Yuanzhuo; Jin, Xiaolong; Li, Jingyuan; Cheng, Xueqi; Jin, Shuyuan

2013-01-01

Privacy information is prone to be leaked by illegal software providers with various motivations. Privacy leak behavior has thus become an important research issue of cyber security. However, existing approaches can only qualitatively analyze privacy leak behavior of software applications. No quantitative approach, to the best of our knowledge, has been developed in the open literature. To fill this gap, in this paper we propose for the first time four quantitative metrics, namely, possibility, severity, crypticity, and manipulability, for privacy leak behavior analysis based on Privacy Petri Net (PPN). In order to compare the privacy leak behavior among different software, we further propose a comprehensive metric, namely, overall leak degree, based on these four metrics. Finally, we validate the effectiveness of the proposed approach using real-world software applications. The experimental results demonstrate that our approach can quantitatively analyze the privacy leak behaviors of various software types and reveal their characteristics from different aspects. PMID:24066046

Comprehensive quantitative analysis on privacy leak behavior.

PubMed

Fan, Lejun; Wang, Yuanzhuo; Jin, Xiaolong; Li, Jingyuan; Cheng, Xueqi; Jin, Shuyuan

2013-01-01

Privacy information is prone to be leaked by illegal software providers with various motivations. Privacy leak behavior has thus become an important research issue of cyber security. However, existing approaches can only qualitatively analyze privacy leak behavior of software applications. No quantitative approach, to the best of our knowledge, has been developed in the open literature. To fill this gap, in this paper we propose for the first time four quantitative metrics, namely, possibility, severity, crypticity, and manipulability, for privacy leak behavior analysis based on Privacy Petri Net (PPN). In order to compare the privacy leak behavior among different software, we further propose a comprehensive metric, namely, overall leak degree, based on these four metrics. Finally, we validate the effectiveness of the proposed approach using real-world software applications. The experimental results demonstrate that our approach can quantitatively analyze the privacy leak behaviors of various software types and reveal their characteristics from different aspects.

Perioperative complications of sleeve gastrectomy: Review of the literature.

PubMed

Iannelli, Antonio; Treacy, Patrick; Sebastianelli, Lionel; Schiavo, Luigi; Martini, Francesco

2018-05-04

Sleeve gastrectomy (SG) has known a spectacular rise worldwide during the last decade. The absence of digestive anastomosis simplifies the surgical technique, reducing anastomosis-related complications such as fistula, stricture and marginal ulcer. Furthermore, the respect for digestive continuity preserves the functions of pylorus, that regulates gastric emptying, and duodenum, where calcium, B vitamins and iron are absorbed. Despite the multiple advantages, SG also has specific complications such as bleeding, stenosis, portal thrombosis and leak. The staple line leak at the oesophagogastric junction is the most feared complication and its prevention remains difficult, as the involved mechanisms have been only partially elucidated. Its management is long and requires a multidisciplinary technical platform including Intensive Care Unit, digestive endoscopy and interventional radiology as well as a specialised surgeon. The aim of this review is to explain in detail the perioperative complications of SG, their prevention and treatment, referring to the most recent available literature.

Treatment of sleep-disordered breathing with positive airway pressure devices: technology update.

PubMed

Johnson, Karin Gardner; Johnson, Douglas Clark

2015-01-01

Many types of positive airway pressure (PAP) devices are used to treat sleep-disordered breathing including obstructive sleep apnea, central sleep apnea, and sleep-related hypoventilation. These include continuous PAP, autoadjusting CPAP, bilevel PAP, adaptive servoventilation, and volume-assured pressure support. Noninvasive PAP has significant leak by design, which these devices adjust for in different manners. Algorithms to provide pressure, detect events, and respond to events vary greatly between the types of devices, and vary among the same category between companies and different models by the same company. Many devices include features designed to improve effectiveness and patient comfort. Data collection systems can track compliance, pressure, leak, and efficacy. Understanding how each device works allows the clinician to better select the best device and settings for a given patient. This paper reviews PAP devices, including their algorithms, settings, and features.

Radiation-pressure acceleration of ion beams from nanofoil targets: the leaky light-sail regime.

PubMed

Qiao, B; Zepf, M; Borghesi, M; Dromey, B; Geissler, M; Karmakar, A; Gibbon, P

2010-10-08

A new ion radiation-pressure acceleration regime, the "leaky light sail," is proposed which uses sub-skin-depth nanometer foils irradiated by circularly polarized laser pulses. In the regime, the foil is partially transparent, continuously leaking electrons out along with the transmitted laser field. This feature can be exploited by a multispecies nanofoil configuration to stabilize the acceleration of the light ion component, supplementing the latter with an excess of electrons leaked from those associated with the heavy ions to avoid Coulomb explosion. It is shown by 2D particle-in-cell simulations that a monoenergetic proton beam with energy 18 MeV is produced by circularly polarized lasers at intensities of just 10¹⁹  W/cm². 100 MeV proton beams are obtained by increasing the intensities to 2 × 10²⁰  W/cm².

Sewage Monitors

NASA Technical Reports Server (NTRS)

1987-01-01

Every U.S. municipality must determine how much waste water it is processing and more importantly, how much is going unprocessed into lakes and streams either because of leaks in the sewer system or because the city's sewage facilities were getting more sewer flow than they were designed to handle. ADS Environmental Services, Inc.'s development of the Quadrascan Flow Monitoring System met the need for an accurate method of data collection. The system consists of a series of monitoring sensors and microcomputers that continually measure water depth at particular sewer locations and report their findings to a central computer. This provides precise information to city managers on overall flow, flow in any section of the city, location and severity of leaks and warnings of potential overload. The core technology has been expanded upon in terms of both technical improvements, and functionality for new applications, including event alarming and control for critical collection system management problems.

40 CFR 63.1086 - How must I monitor for leaks to cooling water?

Code of Federal Regulations, 2010 CFR

2010-07-01

... monitor for leaks to cooling water? You must monitor for leaks to cooling water by monitoring each heat... system so that the cooling water flow rate is 51,031 liters per minute or less so that a leak of 3.06 kg... detected a leak. (b) Individual heat exchangers. Monitor the cooling water at the entrance and exit of each...

40 CFR 264.196 - Response to leaks or spills and disposition of leaking or unfit-for-use tank systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Response to leaks or spills and... HAZARDOUS WASTE TREATMENT, STORAGE, AND DISPOSAL FACILITIES Tank Systems § 264.196 Response to leaks or... system from which there has been a leak or spill, or which is unfit for use, must be removed from service...

Temperature and Atomic Oxygen Effects on Helium Leak Rates of a Candidate Main Interface Seal

NASA Technical Reports Server (NTRS)

Penney, Nicholas; Wasowski, Janice L.; Daniels, Christopher C.

2011-01-01

Helium leak tests were completed to characterize the leak rate of a 54 in. diameter composite space docking seal design in support of the National Aeronautics and Space Administration s (NASA's) Low Impact Docking System (LIDS). The evaluated seal design was a candidate for the main interface seal on the LIDS, which would be compressed between two vehicles, while docked, to prevent the escape of breathable air from the vehicles and into the vacuum of space. Leak tests completed at nominal temperatures of -30, 20, and 50 C on untreated and atomic oxygen (AO) exposed test samples were examined to determine the influence of both test temperature and AO exposure on the performance of the composite seal assembly. Results obtained for untreated seal samples showed leak rates which increased with increased test temperature. This general trend was not observed in tests of the AO exposed specimens. Initial examination of collected test data suggested that AO exposure resulted in higher helium leak rates, however, further analysis showed that the differences observed in the 20 and 50 C tests between the untreated and AO exposed samples were within the experimental error of the test method. Lack of discernable trends in the test data prevented concrete conclusions about the effects of test temperature and AO exposure on helium leak rates of the candidate seal design from being drawn. To facilitate a comparison of the current test data with results from previous leak tests using air as the test fluid, helium leak rates were converted to air leak rates using standard conversion factors for viscous and molecular flow. Flow rates calculated using the viscous flow conversion factor were significantly higher than the experimental air leakage values, whereas values calculated using the molecular flow conversion factor were significantly lower than the experimentally obtained air leak rates. The difference in these sets of converted flow rates and their deviation from the experimentally obtained air leak rate data suggest that neither conversion factor can be used alone to accurately convert helium leak rates to equivalent air leak rates for the test seals evaluated in this study; other leak phenomena, including permeation, must also be considered.

Differences in Binding and Monitoring Mechanisms Contribute to Lifespan Age Differences in False Memory

ERIC Educational Resources Information Center

Fandakova, Yana; Shing, Yee Lee; Lindenberger, Ulman

2013-01-01

Based on a 2-component framework of episodic memory development across the lifespan (Shing & Lindenberger, 2011), we examined the contribution of memory-related binding and monitoring processes to false memory susceptibility in childhood and old age. We administered a repeated continuous recognition task to children (N = 20, 10-12 years),…

Complex Span versus Updating Tasks of Working Memory: The Gap Is Not that Deep

ERIC Educational Resources Information Center

Schmiedek, Florian; Hildebrandt, Andrea; Lovden, Martin; Wilhelm, Oliver; Lindenberger, Ulman

2009-01-01

How to best measure working memory capacity is an issue of ongoing debate. Besides established complex span tasks, which combine short-term memory demands with generally unrelated secondary tasks, there exists a set of paradigms characterized by continuous and simultaneous updating of several items in working memory, such as the n-back, memory…

Sensitivity and specificity of intrathecal fluorescein and white light excitation for detecting intraoperative cerebrospinal fluid leak in endoscopic skull base surgery: a prospective study.

PubMed

Raza, Shaan M; Banu, Matei A; Donaldson, Angela; Patel, Kunal S; Anand, Vijay K; Schwartz, Theodore H

2016-03-01

The intraoperative detection of CSF leaks during endonasal endoscopic skull base surgery is critical to preventing postoperative CSF leaks. Intrathecal fluorescein (ITF) has been used at varying doses to aid in the detection of intraoperative CSF leaks. However, the sensitivity and specificity of ITF at certain dosages is unknown. A prospective database of all endoscopic endonasal procedures was reviewed. All patients received 25 mg ITF diluted in 10 ml CSF and were pretreated with dexamethasone and Benadryl. Immediately after surgery, the operating surgeon prospectively noted if there was an intraoperative CSF leak and fluorescein was identified. The sensitivity, specificity, and positive and negative predictive power of ITF for detecting intraoperative CSF leak were calculated. Factors correlating with postoperative CSF leak were determined. Of 419 patients, 35.8% of patients did not show a CSF leak. Fluorescein-tinted CSF (true positive) was noted in 59.7% of patients and 0 false positives were encountered. CSF without fluorescein staining (false negative) was noted in 4.5% of patients. The sensitivity and specificity of ITF were 92.9% and 100%, respectively. The negative and positive predictive values were 88.8% and 100%, respectively. Postoperative CSF leaks only occurred in true positives at a rate of 2.8%. ITF is extremely specific and very sensitive for detecting intraoperative CSF leaks. Although false negatives can occur, these patients do not appear to be at risk for postoperative CSF leak. The use of ITF may help surgeons prevent postoperative CSF leaks by intraoperatively detecting and confirming a watertight repair.

Risk factors for cerebrospinal fluid leak in pediatric patients undergoing endoscopic endonasal skull base surgery.

PubMed

Stapleton, Amanda L; Tyler-Kabara, Elizabeth C; Gardner, Paul A; Snyderman, Carl H; Wang, Eric W

2017-02-01

To determine the risk factors associated with cerebrospinal fluid (CSF) leak following endoscopic endonasal surgery (EES) for pediatric skull base lesions. Retrospective chart review of pediatric patients (ages 1 month to 18 years) treated for skull base lesions with EES from 1999 to 2014. Five pathologies were reviewed: craniopharyngioma, clival chordoma, pituitary adenoma, pituitary carcinoma, and Rathke's cleft cyst. Fisher's exact tests were used to evaluate the different factors to determine which had a statistically higher risk of leading to a post-operative CSF leak. 55 pediatric patients were identified who underwent 70 EES's for tumor resection. Of the 70 surgeries, 47 surgeries had intraoperative CSF leaks that were repaired at the time of surgery. 11 of 47 (23%) surgeries had post-operative CSF leaks that required secondary operative repair. Clival chordomas had the highest CSF leak rate at 36%. There was no statistical difference in leak rate based on the type of reconstruction, although 28% of cases that used a vascularized flap had a post-operative leak, whereas only 9% of those cases not using a vascularized flap had a leak. Post-operative hydrocephalus and perioperative use of a lumbar drain were not significant risk factors. Pediatric patients with an intra-operative CSF leak during EES of the skull base have a high rate of post-operative CSF leaks. Clival chordomas appear to be a particularly high-risk group. The use of vascularized flaps and perioperative lumbar drains did not statistically decrease the rate of post-operative CSF leak. Copyright © 2017 Elsevier B.V. All rights reserved.

Postoperative esophageal leak management with the Polyflex esophageal stent.

PubMed

Freeman, Richard K; Ascioti, Anthony J; Wozniak, Thomas C

2007-02-01

Leak after esophageal anastomosis or perforation repair prolongs hospitalization, prevents oral hydration and nutrition, and can produce localized infection or sepsis. This investigation reviews our experience treating postoperative esophageal leaks with the Polyflex esophageal stent (Boston Scientific, Natick, Mass). Over a 30-month period, patients with a postoperative esophageal leak were treated with the Polyflex stent for leak occlusion. Leak occlusion was confirmed by means of esophagraphy. Patients were followed until their stent was removed and their esophageal leak had resolved. Twenty-one patients had 27 stents placed for leak occlusion after esophagectomy (n = 5), esophageal perforation (n = 5), surgical (n = 4) or endoscopic (n = 2) antireflux procedure, and esophageal diverticulectomy (n = 3) or myotomy (n = 2). The mean interval between surgical intervention and stent placement was 12 +/- 8 days (range, 3-31 days). Occlusion of the leak occurred in 20 patients. One patient experienced a dehiscence of the surgical esophageal perforation repair requiring esophageal diversion. Stent migration requiring repositioning (n = 3) or replacement (n = 4) occurred in 5 (24%) patients. Twenty (95%) stents were removed without residual leak (mean, 51 +/- 43 days; range, 15-175 days). One patient had a stricture after stent removal that required endoscopic dilatation. One patient in this series died. The Polyflex esophageal stent is an effective method for occluding a postoperative esophageal leak. It rapidly eliminates contamination of the mediastinum, pleura, and peritoneum; allows oral hydration and nutrition; and is easily removable. These stents also offer an appealing alternative to traditional esophageal diversion and subsequent reconstruction in patients with a persistent esophageal leak.

Examinations for leak tightness of actively cooled components in ITER and fusion devices

NASA Astrophysics Data System (ADS)

Hirai, T.; Barabash, V.; Carrat, R.; Chappuis, Ph; Durocher, A.; Escourbiac, F.; Merola, M.; Raffray, R.; Worth, L.; Boscary, J.; Chantant, M.; Chuilon, B.; Guilhem, D.; Hatchressian, J.-C.; Hong, S. H.; Kim, K. M.; Masuzaki, S.; Mogaki, K.; Nicolai, D.; Wilson, D.; Yao, D.

2017-12-01

Any leak in one of the ITER actively cooled components would cause significant consequences for machine operations; therefore, the risk of leak must be minimized as much as possible. In this paper, the strategy of examination to ensure leak tightness of the ITER internal components (i.e. examination of base materials, vacuum boundary joints and final components) and the hydraulic parameters for ITER internal components are summarized. The experiences of component tests, especially hot helium leak tests in recent fusion devices, were reviewed and the parameters were discussed. Through these experiences, it was confirmed that the hot He leak test was effective to detect small leak paths which were not always possible to detect by volumetric examination due to limited spatial resolution.

Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

PubMed Central

Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

2016-01-01

Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the biphasic decay was replaced by slow decay. We conclude that, in the presence of adrenergic stimulation, Ca leak can produce biphasic decay; the slow phase results from the leak opposing Ca uptake by SERCA. The degree of leak determines whether decay of Ca waves, biphasic or monophasic, occurs. PMID:26537441

40 CFR 60.4880 - How do I develop a site-specific monitoring plan for my continuous monitoring, bag leak detection...

Code of Federal Regulations, 2011 CFR

2011-07-01

... this section. (1) Install the flow sensor and other necessary equipment in a position that provides a representative flow. (2) Use a flow sensor with a measurement sensitivity of no greater than 2 percent of the...) Install the pressure sensor(s) in a position that provides a representative measurement of the pressure (e...

75 FR 26679 - Fisheries of the Caribbean, Gulf of Mexico, and South Atlantic; Amendment to Emergency Fisheries...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-12

... the Deepwater Horizon oil spill. The initial closure was applicable May 2, 2010 through 12:01 a.m... Horizon oil spill. The initial closed area was applicable from May 2, 2010 through 12:01 a.m., local time... area, due to the evolving nature of the oil spill. The oil that is continuing to leak from the...

Rapid recovery from transient faults in the fault-tolerant processor with fault-tolerant shared memory

NASA Technical Reports Server (NTRS)

Harper, Richard E.; Butler, Bryan P.

1990-01-01

The Draper fault-tolerant processor with fault-tolerant shared memory (FTP/FTSM), which is designed to allow application tasks to continue execution during the memory alignment process, is described. Processor performance is not affected by memory alignment. In addition, the FTP/FTSM incorporates a hardware scrubber device to perform the memory alignment quickly during unused memory access cycles. The FTP/FTSM architecture is described, followed by an estimate of the time required for channel reintegration.

Development of process parameters for 22 nm PMOS using 2-D analytical modeling

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

Maheran, A. H. Afifah; Menon, P. S.; Shaari, S.

2015-04-24

The complementary metal-oxide-semiconductor field effect transistor (CMOSFET) has become major challenge to scaling and integration. Innovation in transistor structures and integration of novel materials are necessary to sustain this performance trend. CMOS variability in the scaling technology becoming very important concern due to limitation of process control; over statistically variability related to the fundamental discreteness and materials. Minimizing the transistor variation through technology optimization and ensuring robust product functionality and performance is the major issue.In this article, the continuation study on process parameters variations is extended and delivered thoroughly in order to achieve a minimum leakage current (I{sub LEAK}) onmore » PMOS planar transistor at 22 nm gate length. Several device parameters are varies significantly using Taguchi method to predict the optimum combination of process parameters fabrication. A combination of high permittivity material (high-k) and metal gate are utilized accordingly as gate structure where the materials include titanium dioxide (TiO{sub 2}) and tungsten silicide (WSi{sub x}). Then the L9 of the Taguchi Orthogonal array is used to analyze the device simulation where the results of signal-to-noise ratio (SNR) of Smaller-the-Better (STB) scheme are studied through the percentage influences of the process parameters. This is to achieve a minimum I{sub LEAK} where the maximum predicted I{sub LEAK} value by International Technology Roadmap for Semiconductors (ITRS) 2011 is said to should not above 100 nA/µm. Final results shows that the compensation implantation dose acts as the dominant factor with 68.49% contribution in lowering the device’s leakage current. The absolute process parameters combination results in I{sub LEAK} mean value of 3.96821 nA/µm where is far lower than the predicted value.« less

Psychological Symptoms and Social Functioning Following Repair of Obstetric Fistula in a Low-Income Setting.

PubMed

Wilson, Sarah M; Sikkema, Kathleen J; Watt, Melissa H; Masenga, Gileard G; Mosha, Mary V

2016-05-01

Objectives Obstetric fistula is a maternal injury that causes uncontrollable leaking of urine or stool, and most women who develop it live in poverty in low-income countries. Obstetric fistula is associated with high rates of stigma and psychological morbidity, but there is uncertainty about the impact of surgical treatment on psychological outcomes. The objective of this exploratory study was to examine changes in psychological symptoms following surgical fistula repair, discharge and reintegration home. Methods Women admitted for surgical repair of obstetric fistula were recruited from a Tanzanian hospital serving a rural catchment area. Psychological symptoms and social functioning were assessed prior to surgery. Approximately 3 months after discharge, a data collector visited the patients' homes to repeat psychosocial measures and assess self-reported incontinence. Baseline to follow-up differences were measured with paired t tests controlling for multiple comparisons. Associations between psychological outcomes and leaking were assessed with t tests and Pearson correlations. Results Participants (N = 28) had been living with fistula for an average of 11 years. Baseline psychological distress was high, and decreased significantly at follow-up. Participants who self-reported continued incontinence at follow-up endorsed significantly higher PTSD and depression symptoms than those who reported being cured, and severity of leaking was associated with psychological distress. Conclusions Fistula patients experience improvements in mental health at 3 months after discharge, but these improvements are curtailed when women experience residual leaking. Given the rate of stress incontinence following surgery, it is important to prepare fistula patients for the possibility of incomplete cure and help them develop appropriate coping strategies.

Distribution System Audits, Leak Detection, and Repair: Kirtland Air Force Base Leak Detection and Repair Program

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

None

Water Best Management Practice #3 Fact Seet: Outlines how a leak detection and repair program helped Kirtland Air Force Base perform distribution system audits, leak detection, and repair to conserve water site-wide.

Double Shell Tank AY-102 Radioactive Waste Leak Investigation

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

Washenfelder, Dennis J.

2014-04-10

PowerPoint. The objectives of this presentation are to: Describe Effort to Determine Whether Tank AY-102 Leaked; Review Probable Causes of the Tank AY-102 Leak; and, Discuss Influence of Leak on Hanford’s Double-Shell Tank Integrity Program.

Method and means of passive detection of leaks in buried pipes

DOEpatents

Claytor, T.

1979-10-30

A method and means for passive detection of a leak in a buried pipe containing fluid under pressure includes a plurality of acoustic detectors that are placed in contact with the pipe. Noise produced by the leak is detected by the detectors, and the detected signals are correlated to locate the leak. In one embodiment of the invention two detectors are placed at different locations to locate a leak between them. In an alternate embodiment two detectors of different waves are placed at substantially the same location to determine the distance of the leak from the location.

Method and means of passive detection of leaks in buried pipes

DOEpatents

Claytor, Thomas N.

1981-01-01

A method and means for passive detection of a leak in a buried pipe containing fluid under pressure includes a plurality of acoustic detectors that are placed in contact with the pipe. Noise produced by the leak is detected by the detectors, and the detected signals are correlated to locate the leak. In one embodiment of the invention two detectors are placed at different locations to locate a leak between them. In an alternate embodiment two detectors of different waves are placed at substantially the same location to determine the distance of the leak from the location.

Leak testing in parenteral packaging: establishment of direct correlation between helium leak rate measurements and microbial ingress for two different leak types.

PubMed

Morrical, Bradley D; Goverde, Marcel; Grausse, Jean; Gerwig, Tanja; Vorgrimler, Lothar; Morgen, Rachel; Büttiker, Jean-Pierre

2007-01-01

A direct test method using helium leak detection was developed to determine microbial ingress in parenteral vial/rubber closure systems. The purpose of this study was to establish a direct correlation between the helium leak rate and the presence of ingress when vials were submersed under pressure in a broth of bacteria. Results were obtained for two different types of leaks: microholes that have been laser-drilled into thin metal plates, and thin copper wire that was placed between the rubber closure and the glass vial's sealing surface. The results from the microholes showed that the helium leak rate was a function of the square of the hole diameter and fit well with theoretical calculations. The relationship with the wire gave a far more complex dependence and was not modeled theoretically. Comparison with the microbial challenge showed that for microholes a lower size limit was found to be 2 microm with a corresponding leak rate of 1.4 x 10(-3) mbarl/s. For the fine wire experiment the lower limit was 15-microm wire and a corresponding leak rate of 1.3 x 10(-5) mbarl/s. From these tests a safe, lower limit, leak rate was established.

Drain amylase aids detection of anastomotic leak after esophagectomy.

PubMed

Baker, Erin H; Hill, Joshua S; Reames, Mark K; Symanowski, James; Hurley, Susie C; Salo, Jonathan C

2016-04-01

Anastomotic leak following esophagectomy is associated with significant morbidity and mortality. As hospital length of stay decreases, the timely diagnosis of leak becomes more important. We evaluated CT esophagram, white blood count (WBC), and drain amylase levels in the early detection of anastomotic leak. The diagnostic performance of CT esophagram, drain amylase >800 IU/L, and WBC >12,000/µL within the first 10 days after surgery in predicting leak at any time after esophagectomy was calculated. Anastomotic leak occurred in 13 patients (13%). CT esophagram performed within 10 days of surgery diagnosed six of these leaks with a sensitivity of 0.54. Elevation in drain amylase level within 10 days of surgery diagnosed anastomotic leak with a sensitivity of 0.38. When the CT esophagram and drain amylase were combined, the sensitivity rose to 0.69 with a specificity of 0.98. WBC elevation had a sensitivity of 0.92, with a specificity of 0.34. Among 30 patients with normal drain amylase and a normal WBC, one developed an anastomotic leak. Drain amylase adds to the sensitivity of CT esophagram in the early detection of anastomotic leak. Selected patients with normal drain amylase levels and normal WBC may be able to safely forgo CT esophagram.

Cerebrospinal fluid rhinorrhea following trans-sphenoidal pituitary macroadenoma surgery: experience from 592 patients.

PubMed

Han, Zong-Li; He, Dong-Sheng; Mao, Zhi-Gang; Wang, Hai-Jun

2008-06-01

To determine the incidence, risk factors, diagnostic procedures, and management of cerebrospinal fluid (CSF) leaks following trans-sphenoidal pituitary macroadenoma surgery. Retrospective analysis of 592 patients. Intra- and post-operative CSF leaks occurred in 14.2 and 4.4% of patients, respectively. Surgical revision, tumor consistency, and tumor margins were independently associated with intra-operative leaks, while the tumor size, consistency, and margins were risk factors of post-operative leaks. The intra-operative leak rate of ACTH adenomas was greater than all other types combined; the incidence of post-operative CSF leaks was highest for FSH adenomas. There were no significant differences among various techniques and we achieved an initial repair success rates of 83.3 and 92.9% for intra- and post-operative CSF leaks, respectively. Of the 26 patients with post-operative CSF leaks, five were complicated by meningitis and four by post-infectious hydrocephalus which required ventriculoperitoneal shunts. CSF leaks have a propensity to occur in cases with fibrous tumors or tumors with indistinct margin and may have some relationship with the tumor type. Endoscopic and microscopic repairs were shown to be effective techniques in managing these types of leaks. Post-infectious hydrocephalus may influence the outcome of the repair and ventriculoperitoneal shunts were necessary in some cases.

Seven Ventilators Challenged With Leaks During Neonatal Nasal CPAP: An Experimental Pilot Study.

PubMed

Drevhammar, Thomas; Nilsson, Kjell; Zetterström, Henrik; Jonsson, Baldvin

2015-07-01

Nasal CPAP is the most common respiratory support for neonates. Several factors are considered important for effective treatment, including leaks at the patient interface and the delivery of pressure-stable CPAP. Investigations of pressure stability during leaks should include both the change in the mean delivered CPAP and the pressure variation during each breath. The aim of this study was to examine the response of ventilators delivering nasal CPAP when challenged with leaks at the patient interface. Seven ventilators providing nasal CPAP at 4 cm H2O were challenged with leaks during simulated neonatal breathing. Leak was applied for 15 consecutive breaths at a constant level (1-4 L/min). The 2 aspects of pressure stability were evaluated by measuring the mean delivered CPAP and the amplitude of pressure swings before, during, and after leaks. The ability to maintain the delivered CPAP and the amplitude of pressure swings varied greatly among the 7 ventilators before, during, and after leaks. Four of the ventilators tested have built-in leak compensation. There was no simple relationship between maintaining delivered CPAP during leaks and providing CPAP with low pressure swing amplitude. Maintaining the delivered CPAP and providing this without pressure swings are 2 separate aspects of pressure stability, and investigations concerning the clinical importance of pressure stability should address both aspects. This study also shows that compensation for leaks does not necessarily provide pressure-stable CPAP. Copyright © 2015 by Daedalus Enterprises.

Developmental Dissociation Between the Maturation of Procedural Memory and Declarative Memory

PubMed Central

Finn, Amy S.; Kalra, Priya B.; Goetz, Calvin; Leonard, Julia A.; Sheridan, Margaret A.; Gabrieli, John D. E.

2015-01-01

Declarative memory and procedural memory are known to be two fundamentally different kinds of memory that are dissociable in their psychological characteristics and measurement (explicit versus implicit) and in the neural systems that subserve each kind of memory. Declarative memory abilities are known to improve from childhood through young adulthood, but the developmental maturation of procedural memory is largely unknown. We compared 10-year-old children and young adults on measures of declarative memory, working memory capacity, and four measures of procedural memory that have been strongly dissociated from declarative memory (mirror tracing, rotary pursuit, probabilistic classification, and artificial grammar). Children had lesser declarative memory ability and lesser working memory capacity than the adults, but exhibited learning equivalent to adults on all four measures of procedural memory. Declarative and procedural memory are, therefore, developmentally dissociable, with procedural memory being adult-like by age 10 and declarative memory continuing to mature into young adulthood. PMID:26560675

The Cognitive Neuroscience of Human Memory Since H.M

PubMed Central

Squire, Larry R.; Wixted, John T.

2011-01-01

Work with patient H.M., beginning in the 1950s, established key principles about the organization of memory that inspired decades of experimental work. Since H.M., the study of human memory and its disorders has continued to yield new insights and to improve understanding of the structure and organization of memory. Here we review this work with emphasis on the neuroanatomy of medial temporal lobe and diencephalic structures important for memory, multiple memory systems, visual perception, immediate memory, memory consolidation, the locus of long-term memory storage, the concepts of recollection and familiarity, and the question of how different medial temporal lobe structures may contribute differently to memory functions. PMID:21456960

Multiple Transient Memories in Experiments on Sheared Non-Brownian Suspensions

NASA Astrophysics Data System (ADS)

Paulsen, Joseph D.; Keim, Nathan C.; Nagel, Sidney R.

2014-08-01

A system with multiple transient memories can remember a set of inputs but subsequently forgets almost all of them, even as they are continually applied. If noise is added, the system can store all memories indefinitely. The phenomenon has recently been predicted for cyclically sheared non-Brownian suspensions. Here we present experiments on such suspensions, finding behavior consistent with multiple transient memories and showing how memories can be stabilized by noise.

A Hydrogen Leak Detection System for Aerospace and Commercial Applications

NASA Technical Reports Server (NTRS)

Hunter, Gary W.; Makel, D. B.; Jansa, E. D.; Patterson, G.; Cova, P. J.; Liu, C. C.; Wu, Q. H.; Powers, W. T.

1995-01-01

Leaks on the space shuttle while on the launch pad have generated interest in hydrogen leak monitoring technology. Microfabricated hydrogen sensors are being fabricated at Case Western Reserve University (CWRU) and tested at NASA Lewis Research Center (LeRC). These sensors have been integrated into hardware and software designed by Aerojet. This complete system allows for multipoint leak monitoring designed to provide leak source and magnitude information in real time. The monitoring system processes data from the hydrogen sensors and presents the operator with a visual indication of the leak location and magnitude. Although the leak monitoring system was designed for hydrogen propulsion systems, the possible applications of this monitoring system are wide ranged. This system is in operation in an automotive application which requires high sensitivity to hydrogen.

Long-life leak standard assembly

DOEpatents

Basford, James A.; Mathis, John E.; Wright, Harlan C.

1982-01-01

The present invention is directed to a portable leak standard assembly which is capable of providing a stream of high-purity reference gas at a virtually constant flow rate over an extensive period of time. The leak assembly comprises a high pressure reservoir coupled to a metal leak valve through a valve-controlled conduit. A reproducible leak valve useful in this assembly is provided by a metal tube crimped with a selected pressure loading for forming an orifice in the tube with this orifice being of a sufficient size to provide the selected flow rate. The leak valve assembly is formed of metal so that it can be "baked-out" in a vacuum furnace to rid the reservoir and attendent components of volatile impurities which reduce the efficiency of the leak standard.

Long-life leak standard assembly. [Patent application

DOEpatents

Basford, J.A.; Mathis, J.E.; Wright, H.C.

1980-11-12

The present invention is directed to a portable leak standard assembly which is capable of providing a stream of high-purity reference gas at a virtually constant flow rate over an extensive period of time. The leak assembly comprises a high pressure reservoir coupled to a metal leak valve through a valve-controlled conduit. A reproducible leak valve useful in this assembly is provided by a metal tube crimped with a selected pressure loading for forming an orifice in the tube with this orifice being of a sufficient size to provide the selected flow rate. The leak valve assembly is formed of metal so that it can be baked-out in a vacuum furnace to rid the reservoir and attendent components of volatile impurities which reduce the efficiency of the leak standard.

Comprehensive leak detection survey and benefit/cost analysis

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

Scholze, R.J. Jr.; Maloney, S.W.

1995-06-01

Fort Carson, Colorado was the site of a comprehensive leak detection investigation of the potable water system with the express purpose of quantifying the benefits to be derived by a military installation from use of leak detection and repair technology. Military bases are often the size of a small city and one Directorate or Department has responsibility for all real estate (buildings, roads, grounds, etc.) unlike a municipal public works department. The investigation used state of the art noise correlation and computer correlation technology to survey the distribution system mains. This was complemented by a building to building survey coveringmore » office and commercial buildings along with family and barracks housing where investigators entered buildings and quantified visible leaks in faucets and water closets, etc. Following repairs and a year`s time, a follow-on survey is performed to again examine all aspects of the system. The result was a complete economic evaluation and benefit/cost analysis of the installation. Representative findings include: the majority of distribution system leaks were at hydrants or similar appurtenances; and family housing was found to be the other major concentration of leaks. However, where the first survey found 80 percent of housing units had leaks, findings from the second round on the order of 20 percent. Office buildings were found from the first survey to not merit follow-on attention due to limited numbers of leaks. Water-consciousness was raised for both the responsible directorate and individuals in family housing and leak repair was given a higher priority for repairs. This paper will outline the leak detection methodology used, characterize the types and patterns of leaks found, introduce an economic analysis for the entire leak detection process, and finally, provide lessons learned with practical results and implications.« less

Quantitative computed tomography versus spirometry in predicting air leak duration after major lung resection for cancer.

PubMed

Ueda, Kazuhiro; Kaneda, Yoshikazu; Sudo, Manabu; Mitsutaka, Jinbo; Li, Tao-Sheng; Suga, Kazuyoshi; Tanaka, Nobuyuki; Hamano, Kimikazu

2005-11-01

Emphysema is a well-known risk factor for developing air leak or persistent air leak after pulmonary resection. Although quantitative computed tomography (CT) and spirometry are used to diagnose emphysema, it remains controversial whether these tests are predictive of the duration of postoperative air leak. Sixty-two consecutive patients who were scheduled to undergo major lung resection for cancer were enrolled in this prospective study to define the best predictor of postoperative air leak duration. Preoperative factors analyzed included spirometric variables and area of emphysema (proportion of the low-attenuation area) that was quantified in a three-dimensional CT lung model. Chest tubes were removed the day after disappearance of the air leak, regardless of pleural drainage. Univariate and multivariate proportional hazards analyses were used to determine the influence of preoperative factors on chest tube time (air leak duration). By univariate analysis, site of resection (upper, lower), forced expiratory volume in 1 second, predicted postoperative forced expiratory volume in 1 second, and area of emphysema (< 1%, 1% to 10%, > 10%) were significant predictors of air leak duration. By multivariate analysis, site of resection and area of emphysema were the best independent determinants of air leak duration. The results were similar for patients with a smoking history (n = 40), but neither forced expiratory volume in 1 second nor predicted postoperative forced expiratory volume in 1 second were predictive of air leak duration. Quantitative CT is superior to spirometry in predicting air leak duration after major lung resection for cancer. Quantitative CT may aid in the identification of patients, particularly among those with a smoking history, requiring additional preventive procedures against air leak.

Postoperative air leak grading is useful to predict prolonged air leak after pulmonary lobectomy.

PubMed

Oh, Sang Gi; Jung, Yochun; Jheon, Sanghoon; Choi, Yunhee; Yun, Ju Sik; Na, Kook Joo; Ahn, Byoung Hee

2017-01-23

Results of studies to predict prolonged air leak (PAL; air leak longer than 5 days) after pulmonary lobectomy have been inconsistent and are of limited use. We developed a new scale representing the amount of early postoperative air leak and determined its correlation with air leak duration and its potential as a predictor of PAL. We grade postoperative air leak using a 5-grade scale. All 779 lobectomies from January 2005 to December 2009 with available medical records were reviewed retrospectively. We devised six 'SUM' variables using air leak grades in the initial 72 h postoperatively. Excluding unrecorded cases and postoperative broncho-pleural fistulas, there were 720 lobectomies. PAL occurred in 135 cases (18.8%). Correlation analyses showed each SUM variable highly correlated with air leak duration, and the SUM 4to9 , which was the sum of six consecutive values of air leak grades for every 8 h record on postoperative days 2 and 3, was proved to be the most powerful predictor of PAL; PAL could be predicted with 75.7% and 77.7% positive and negative predictive value, respectively, when SUM 4to9  ≥ 16. When 4 predictors derived from multivariable logistic regression of perioperative variables were combined with SUM 4to9 , there was no significant increase in predictability compared with SUM 4to9 alone. This simple new method to predict PAL using SUM 4to9 showed that the amount of early postoperative air leak is the most powerful predictor of PAL, therefore, grading air leak after pulmonary lobectomy is a useful method to predict PAL.

Efficacy and Safety of the Over-the-Scope Clip (OTSC) System in the Management of Leak and Fistula After Laparoscopic Sleeve Gastrectomy: a Systematic Review.

PubMed

Shoar, Saeed; Poliakin, Lauren; Khorgami, Zhamak; Rubenstein, Rebecca; El-Matbouly, Moamena; Levin, Jun L; Saber, Alan A

2017-09-01

Endoscopic management of leaks/fistulas after laparoscopic sleeve gastrectomy (LSG) is gaining popularity in the bariatric surgery. This study aimed to review the efficacy and safety of over-the-scope-clip (OTSC) system in endoscopic closure of post-LSG leak/fistula. PubMed/Medline and major journals of the field were systematically reviewed for studies on endoscopic closure of post-LSG leaks/fistula by means of the OTSC system. A total of ten eligible studies including 195 patients with post-LSG leaks/fistula were identified. The time between LSG and leak/fistula ranged from 1 day to 803 days. Most of the leaks/fistula were located at the proximal staple line, and they sized from 3 to 20 mm. Time between leak diagnosis and OTSC clipping ranged from 0 to 271 days. Thirty-three out of 53 patients (63.5%) required one clip for closure of the lesion. Regarding the OTSC-related complications, a leak occurred in five patients (9.3%) and OTSC migration, stenosis, and tear each in one patient (1.8%). Of the 73 patients with post-LSG leak treated with OTSC, 63 patients had an overall successful closure (86.3%). OTSC system is a promising endoscopic approach for management of post-LSG leaks in appropriately selected patients. Unfortunately, most studies are series with a small sample size, short-term follow-up, and mixed data of concomitant procedures with OTSC. Further studies should distinguish the net efficacy of the OTSC system from other concomitant procedures in treatment of post-LSG leak.

A prospective algorithm for the management of air leaks after pulmonary resection.

PubMed

Cerfolio, R J; Tummala, R P; Holman, W L; Zorn, G L; Kirklin, J K; McGiffin, D C; Naftel, D C; Pacifico, A D

1998-11-01

Air leaks (ALs) are a common complication after pulmonary resection, yet there is no consensus on their management. An algorithm for the management of chest tubes (CT) and ALs was applied prospectively to 101 consecutive patients who underwent elective pulmonary resection. Air leaks were graded daily as forced expiratory only, expiratory only, inspiratory only, or continuous. All CTs were kept on 20 cm of suction until postoperative day 2 and were then converted to water seal. On postoperative day 3, if both a pneumothorax and AL were present, the CT was placed to 10 cm H2O of suction. If a pneumothorax was present without an AL, the CT was returned to 20 cm H2O of suction. Air leaks that persisted after postoperative day 7 were treated with talc slurry. There were 101 patients (67 men); on postoperative day 1, 26 had ALs and all were expiratory only. Univariable analysis showed a low ratio of forced expiratory volume in 1 second to forced vital capacity (FEV1/FVC) (p = 0.005), increased age (p = 0.007), increased ratio of residual volume to total lung capacity (RV/TLC) (p = 0.04), increased RV (p = 0.02), and an increased functional residual capacity (FRC) (p = 0.02) to predict the presence of an AL on postoperative day 1. By postoperative day 2, 22 patients had expiratory ALs. After 12 hours of water seal, 13 of the 22 patients' ALs had stopped, and 3 more sealed by the morning of postoperative day 3. However, 2 of the 6 patients whose ALs continued experienced a pneumothorax. Five of the 6 patients with ALs on postoperative day 4 still had ALs on postoperative day 7, and all were treated by talc slurry through the CT. All ALs resolved within 24 hours after talc slurry. Most ALs after pulmonary resection are expiratory only. A low FEV1/FVC ratio, increased age, increased RV/TLC ratio, increased RV, and an increased FRC were predictors of having an ALs on postoperative day 1. Conversion from suction to water seal is an effective way of sealing expiratory AL, and pneumothorax is rare. If an expiratory AL does not stop by postoperative day 4 it will probably persist until postoperative day 7, and talc slurry may be an effective treatment.

Single-Shell Tanks Leak Integrity Elements/ SX Farm Leak Causes and Locations - 12127

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

Girardot, Crystal; Harlow, Don; Venetz, Theodore

2012-07-01

Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-91F Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1.more » Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal 1-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX- 111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and dry-wells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to leak detection. In-tank parameters can include temperature of the supernatant and sludge, types of waste, and chemical determination by either transfer or sample analysis. Ex-tank information can be assembled from many sources including design media, construction conditions, technical specifications, and other sources. Five conditions may have contributed to SX Farm tank liner failure including: tank design, thermal shock, chemistry-corrosion, liner behavior (bulging), and construction temperature. Tank design did not apparently change from tank to tank for the SX Farm tanks; however, there could be many unknown variables present in the quality of materials and quality of construction. Several significant SX Farm tank design changes occurred from previous successful tank farm designs. Tank construction occurred in winter under cold conditions which could have affected the ductile to brittle transition temperature of the tanks. The SX Farm tanks received high temperature boiling waste from REDOX which challenged the tank design with rapid heat up and high temperatures. All eight of the leaking SX Farm tanks had relatively high rate of temperature rise. Supernatant removal with subsequent nitrate leaching was conducted in all but three of the eight leaking tanks prior to leaks being detected. It is possible that no one characteristic of the SX Farm tanks could in isolation from the others have resulted in failure. However, the application of so many stressors - heat up rate, high temperature, loss of corrosion protection, and tank design working jointly or serially resulted in their failure. Thermal shock coupled with the tank design, construction conditions, and nitrate leaching seem to be the overriding factors that can lead to tank liner failure. The distinction between leaking and sound SX Farm tanks seems to center on the waste types, thermal conditions, and nitrate leaching. (authors)« less

SINGLE-SHELL TANKS LEAK INTEGRITY ELEMENTS/SX FARM LEAK CAUSES AND LOCATIONS - 12127

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

VENETZ TJ; WASHENFELDER D; JOHNSON J

2012-01-25

Washington River Protection Solutions, LLC (WRPS) developed an enhanced single-shell tank (SST) integrity project in 2009. An expert panel on SST integrity was created to provide recommendations supporting the development of the project. One primary recommendation was to expand the leak assessment reports (substitute report or LD-1) to include leak causes and locations. The recommendation has been included in the M-045-9IF Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) as one of four targets relating to SST leak integrity. The 241-SX Farm (SX Farm) tanks with leak losses were addressed on an individual tank basis as part of LD-1.more » Currently, 8 out of 23 SSTs that have been reported to having a liner leak are located in SX Farm. This percentage was the highest compared to other tank farms which is why SX Farm was analyzed first. The SX Farm is comprised of fifteen SSTs built 1953-1954. The tanks are arranged in rows of three tanks each, forming a cascade. Each of the SX Farm tanks has a nominal I-million-gal storage capacity. Of the fifteen tanks in SX Farm, an assessment reported leak losses for the following tanks: 241-SX-107, 241-SX-108, 241-SX-109, 241-SX-111, 241-SX-112, 241-SX-113, 241-SX-114 and 241-SX-115. The method used to identify leak location consisted of reviewing in-tank and ex-tank leak detection information. This provided the basic data identifying where and when the first leaks were detected. In-tank leak detection consisted of liquid level measurement that can be augmented with photographs which can provide an indication of the vertical leak location on the sidewall. Ex-tank leak detection for the leaking tanks consisted of soil radiation data from laterals and drywells near the tank. The in-tank and ex-tank leak detection can provide an indication of the possible leak location radially around and under the tank. Potential leak causes were determined using in-tank and ex-tank information that is not directly related to leak detection. In-tank parameters can include temperature of the supernatant and sludge, types of waste, and chemical determination by either transfer or sample analysis. Ex-tank information can be assembled from many sources including design media, construction conditions, technical specifications, and other sources. Five conditions may have contributed to SX Farm tank liner failure including: tank design, thermal shock, chemistry-corrosion, liner behavior (bulging), and construction temperature. Tank design did not apparently change from tank to tank for the SX Farm tanks; however, there could be many unknown variables present in the quality of materials and quality of construction. Several significant SX Farm tank design changes occurred from previous successful tank farm designs. Tank construction occurred in winter under cold conditions which could have affected the ductile to brittle transition temperature of the tanks. The SX Farm tanks received high temperature boiling waste from REDOX which challenged the tank design with rapid heat up and high temperatures. All eight of the leaking SX Farm tanks had relatively high rate of temperature rise. Supernatant removal with subsequent nitrate leaching was conducted in all but three of the eight leaking tanks prior to leaks being detected. It is possible that no one characteristic of the SX Farm tanks could in isolation from the others have resulted in failure. However, the application of so many stressors - heat up rate, high temperature, loss of corrosion protection, and tank design - working jointly or serially resulted in their failure. Thermal shock coupled with the tank design, construction conditions, and nitrate leaching seem to be the overriding factors that can lead to tank liner failure. The distinction between leaking and sound SX Farm tanks seems to center on the waste types, thermal conditions, and nitrate leaching.« less

Multiple transient memories in sheared suspensions: Robustness, structure, and routes to plasticity

NASA Astrophysics Data System (ADS)

Keim, Nathan C.; Paulsen, Joseph D.; Nagel, Sidney R.

2013-09-01

Multiple transient memories, originally discovered in charge-density-wave conductors, are a remarkable and initially counterintuitive example of how a system can store information about its driving. In this class of memories, a system can learn multiple driving inputs, nearly all of which are eventually forgotten despite their continual input. If sufficient noise is present, the system regains plasticity so that it can continue to learn new memories indefinitely. Recently, Keim and Nagel [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.107.010603 107, 010603 (2011)] showed how multiple transient memories could be generalized to a generic driven disordered system with noise, giving as an example simulations of a simple model of a sheared non-Brownian suspension. Here, we further explore simulation models of suspensions under cyclic shear, focusing on three main themes: robustness, structure, and overdriving. We show that multiple transient memories are a robust feature independent of many details of the model. The steady-state spatial distribution of the particles is sensitive to the driving algorithm; nonetheless, the memory formation is independent of such a change in particle correlations. Finally, we demonstrate that overdriving provides another means for controlling memory formation and retention.

The Evolution of the Wechsler Memory Scale: A Selective Review.

PubMed

Kent, Phillip

2013-02-27

In clinical use since 1940, the Wechsler Memory Scale was formally introduced to the psychological community in 1945. By 1946, it ranked 90th out of the 100 most frequently used psychological tests. By 1969, it was the 19th most used psychological test and the 2nd most used test of memory. By 1982, it was the 12th most used test and the most used memory test-a popularity it continues to enjoy. The present article will briefly trace the origin of the Wechsler Memory Scale and examine its evolution across the revisions that appeared in 1987, 1997, and 2009. Issues with norming and standardization, as well as reliability and validity, will be summarized. It is argued that the test continues to have several serious shortcomings, including a lack of anchoring in an explicit neuroanatomical theory of memory and an underlying factor structure that appears to have changed little despite changes in the manifest structure and content of the test.

Demonstration of rapid and sensitive module leak certification for space station freedom. Final report

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

Dietz, R.N.; Goodrich, R.W.

1991-03-01

A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 {plus_minus} 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 {plus_minus} 0.7, {minus}0.4 {plus_minus} 0.3, and 76 {plus_minus} 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone testmore » facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on {Delta}p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc. 13 refs.« less

Demonstration of rapid and sensitive module leak certification for space station freedom

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

Dietz, R.N.; Goodrich, R.W.

1991-03-01

A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 {plus minus} 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 {plus minus} 0.7, {minus}0.4 {plus minus} 0.3, and 76 {plus minus} 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes formore » a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on {Delta}p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc. 13 refs.« less

Demonstration of rapid and sensitive module leak certification for Space Station Freedom

NASA Technical Reports Server (NTRS)

Dietz, R. N.; Goodrich, R. W.

1991-01-01

A leak detection and quantification demonstration using perflurocarbon tracer (PFT) technology was successfully performed at the NASA Marshall Space Flight Center on January 25, 1991. The real-time Dual Trap Analyzer (DTA) at one-half hour after the start of the first run gave an estimated leak rate of 0.7 mL/min. This has since been refined to be 1.15 (+ or -) 0.09 mL/min. The leak rates in the next three runs were determined to be 9.8 (+ or -) 0.7, -0.4 (+ or -) 0.3, and 76 (+ or -) 6 mL/min, respectively. The theory on leak quantification in the steady-state and time-dependent modes for a single zone test facility was developed and applied to the above determinations. The laboratory PFT analysis system gave a limit-of-detection (LOD) of 0.05 fL for ocPDCH. This is the tracer of choice and is about 100-fold better than that for the DTA. Applied to leak certification, the LOD is about 0.00002 mL/s (0.000075 L/h), a 5 order-of-magnitude improvement over the original leak certification specification. Furthermore, this limit can be attained in a measurement period of 3 to 4 hours instead of days, weeks, or months. A new Leak Certification Facility is also proposed to provide for zonal (three zones) determination of leak rates. The appropriate multizone equations, their solutions, and error analysis have already been derived. A new concept of seal-integrity certification has been demonstrated for a variety of controlled leaks in the range of module leak testing. High structural integrity leaks were shown to have a linear dependence of flow on (Delta)p. The rapid determination of leak rates at different pressures is proposed and is to be determined while subjecting the module to other external force-generating parameters such as vibration, torque, solar intensity, etc.

49 CFR 195.444 - CPM leak detection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false CPM leak detection. 195.444 Section 195.444... PIPELINE Operation and Maintenance § 195.444 CPM leak detection. Each computational pipeline monitoring (CPM) leak detection system installed on a hazardous liquid pipeline transporting liquid in single...

Leakage detection in galvanized iron pipelines using ensemble empirical mode decomposition analysis

NASA Astrophysics Data System (ADS)

Amin, Makeen; Ghazali, M. Fairusham

2015-05-01

There are many numbers of possible approaches to detect leaks. Some leaks are simply noticeable when the liquids or water appears on the surface. However many leaks do not find their way to the surface and the existence has to be check by analysis of fluid flow in the pipeline. The first step is to determine the approximate position of leak. This can be done by isolate the sections of the mains in turn and noting which section causes a drop in the flow. Next approach is by using sensor to locate leaks. This approach are involves strain gauge pressure transducers and piezoelectric sensor. the occurrence of leaks and know its exact location in the pipeline by using specific method which are Acoustic leak detection method and transient method. The objective is to utilize the signal processing technique in order to analyse leaking in the pipeline. With this, an EEMD method will be applied as the analysis method to collect and analyse the data.

Continuous CO2 gas monitoring to clarify natural pattern and artificial leakage signals

NASA Astrophysics Data System (ADS)

Joun, W.; Ha, S. W.; Joo, Y. J.; Lee, S. S.; Lee, K. K.

2017-12-01

Continuous CO2 gas monitoring at shallow aquifer is significant for early detection and immediate handling of an aquifer impacted by leaking CO2 gas from the sequestration reservoir. However, it is difficult to decide the origin of CO2 gas because detected CO2 includes not only leaked CO2 but also naturally emitted CO2. We performed CO2 injection and monitoring tests in a shallow aquifer. Before the injection of CO2 infused water, we have conducted continuous monitoring of multi-level soil CO2 gas concentration and physical parameters such as temperature, humidity, pressure, wind speed and direction, and precipitation. The monitoring data represented that CO2 gas concentrations in unsaturated soil zone borehole showed differences at depths and daily variation (360 to 6980 ppm volume). Based on the observed data at 5 m and 8 m depths, vertical flux of gas was calculated as 0.471 L/min (LPM) for inflow from 5 m to 8 m and 9.42E-2 LPM for outflow from 8 m to 5 m. The numerical and analytical models were used to calculate the vertical flux of gas and to compare with observations. The results showed that pressure-based modeling could not explain the rapid change of CO2 gas concentration in borehole. Acknowledgement Financial support was provided by the "R&D Project on Environmental Management of Geologic CO2 Storage" from the KEITI (Project Number: 2014001810003)

Mobile natural gas leak surveys indicate that two utilities have high false negative rates

NASA Astrophysics Data System (ADS)

von Fischer, J. C.; Brewer, P. E.; Chamberlain, S.; Gaylord, A.; von Fischer, J.

2016-12-01

In the distribution systems that carry natural gas to consumers, leaks need to be discovered for safety reasons and to reduce greenhouse gas emissions. However, few utilities have adopted newer laser-based technologies that have greater sensitivity and precision, and instead rely on "industry standard" equipment that is far less sensitive. In partnership with the Environmental Defense Fund and Google, we mapped natural gas leaks in the domains of two anonymous utilities (Utility "A" and "B") using high sensitivity Picarro methane analyzers in Google Street View Cars. Surprisingly, when we shared these results with utilities, their survey crews were unable to find most of the leaks that our survey indicated (84% in A and 80% in B). To investigate this phenomenon, our team visited a subset of the leaks in each utility domain (n=32 in A and n=30 in B), and worked alongside utility surveyors to search the leak indication area, using a Los Gatos Research ultraportable methane analyzer to pinpoint leak locations. We found evidence of natural gas leaks at 69% and 68% of the locations in Utilities A and B respectively where survey crews had found nothing. We describe this as a "false negative" rate for the utility because the utility survey falsely indicated that there was no leak at these locations. Of these false negatives, 7% (n=2 of 32 in A, n=2 of 30 in B) were determined to be Grade 1 leaks requiring immediate repair due to high safety risk. Instrument sensitivity appears to explain some of the false negative rates. In particular, use of some industry standard equipment appears to have created a false sense of confidence among utility surveyors that leaks were not present. However, there was also evidence of communication failures and that surveyors did not use optimal approaches in their search. Based on these findings, we suggest that: 1) mobile deployment of high-precision methane analyzers can help find more natural gas leaks, and 2) use of some hand-held survey instruments may lead to higher rates of false negatives in leak survey and 3) there may be room for improvement in leak survey methodologies.

A risk score to predict the incidence of prolonged air leak after video-assisted thoracoscopic lobectomy: An analysis from the European Society of Thoracic Surgeons database.

PubMed

Pompili, Cecilia; Falcoz, Pierre Emmanuel; Salati, Michele; Szanto, Zalan; Brunelli, Alessandro

2017-04-01

The study objective was to develop an aggregate risk score for predicting the occurrence of prolonged air leak after video-assisted thoracoscopic lobectomy from patients registered in the European Society of Thoracic Surgeons database. A total of 5069 patients who underwent video-assisted thoracoscopic lobectomy (July 2007 to August 2015) were analyzed. Exclusion criteria included sublobar resections or pneumonectomies, lung resection associated with chest wall or diaphragm resections, sleeve resections, and need for postoperative assisted mechanical ventilation. Prolonged air leak was defined as an air leak more than 5 days. Several baseline and surgical variables were tested for a possible association with prolonged air leak using univariable and logistic regression analyses, determined by bootstrap resampling. Predictors were proportionally weighed according to their regression estimates (assigning 1 point to the smallest coefficient). Prolonged air leak was observed in 504 patients (9.9%). Three variables were found associated with prolonged air leak after logistic regression: male gender (P < .0001, score = 1), forced expiratory volume in 1 second less than 80% (P < .0001, score = 1), and body mass index less than 18.5 kg/m 2 (P < .0001, score = 2). The aggregate prolonged air leak risk score was calculated for each patient by summing the individual scores assigned to each variable (range, 0-4). Patients were then grouped into 4 classes with an incremental risk of prolonged air leak (P < .0001): class A (score 0 points, 1493 patients) 6.3% with prolonged air leak, class B (score 1 point, 2240 patients) 10% with prolonged air leak, class C (score 2 points, 1219 patients) 13% with prolonged air leak, and class D (score >2 points, 117 patients) 25% with prolonged air leak. An aggregate risk score was created to stratify the incidence of prolonged air leak after video-assisted thoracoscopic lobectomy. The score can be used for patient counseling and to identify those patients who can benefit from additional intraoperative preventative measures. Copyright © 2016 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

Improved Portable Ultrasonic Leak Detectors

NASA Technical Reports Server (NTRS)

Youngquist, Robert C.; Moerk, John S.; Haskell, William D.; Cox, Robert B.; Polk, Jimmy D.; Strobel, James P.; Luaces, Frank

1995-01-01

Improved portable ultrasonic leak detector features three interchangeable ultrasonic-transducer modules, each suited for operation in unique noncontact or contact mode. One module equipped with ultrasound-collecting horn for use in scanning to detect leaks from distance; horn provides directional sensitivity pattern with sensitivity multiplied by factor of about 6 in forward direction. Another module similar, does not include horn; this module used for scanning close to suspected leak, where proximity of leak more than offsets loss of sensitivity occasioned by lack of horn. Third module designed to be pressed against leaking vessel; includes rugged stainless-steel shell. Improved detectors perform significantly better, smaller, more rugged, and greater sensitivity.

Identification of multiple leaks in pipeline: Linearized model, maximum likelihood, and super-resolution localization

NASA Astrophysics Data System (ADS)

Wang, Xun; Ghidaoui, Mohamed S.

2018-07-01

This paper considers the problem of identifying multiple leaks in a water-filled pipeline based on inverse transient wave theory. The analytical solution to this problem involves nonlinear interaction terms between the various leaks. This paper shows analytically and numerically that these nonlinear terms are of the order of the leak sizes to the power two and; thus, negligible. As a result of this simplification, a maximum likelihood (ML) scheme that identifies leak locations and leak sizes separately is formulated and tested. It is found that the ML estimation scheme is highly efficient and robust with respect to noise. In addition, the ML method is a super-resolution leak localization scheme because its resolvable leak distance (approximately 0.15λmin , where λmin is the minimum wavelength) is below the Nyquist-Shannon sampling theorem limit (0.5λmin). Moreover, the Cramér-Rao lower bound (CRLB) is derived and used to show the efficiency of the ML scheme estimates. The variance of the ML estimator approximates the CRLB proving that the ML scheme belongs to class of best unbiased estimator of leak localization methods.

Helium Mass Spectrometer Leak Detection: A Method to Quantify Total Measurement Uncertainty

NASA Technical Reports Server (NTRS)

Mather, Janice L.; Taylor, Shawn C.

2015-01-01

In applications where leak rates of components or systems are evaluated against a leak rate requirement, the uncertainty of the measured leak rate must be included in the reported result. However, in the helium mass spectrometer leak detection method, the sensitivity, or resolution, of the instrument is often the only component of the total measurement uncertainty noted when reporting results. To address this shortfall, a measurement uncertainty analysis method was developed that includes the leak detector unit's resolution, repeatability, hysteresis, and drift, along with the uncertainty associated with the calibration standard. In a step-wise process, the method identifies the bias and precision components of the calibration standard, the measurement correction factor (K-factor), and the leak detector unit. Together these individual contributions to error are combined and the total measurement uncertainty is determined using the root-sum-square method. It was found that the precision component contributes more to the total uncertainty than the bias component, but the bias component is not insignificant. For helium mass spectrometer leak rate tests where unit sensitivity alone is not enough, a thorough evaluation of the measurement uncertainty such as the one presented herein should be performed and reported along with the leak rate value.

Endoscopic Transmaxillary Transposition of Temporalis Flap for Recurrent Cerebrospinal Fluid Leak Closure.

PubMed

Thomas, Regi; Girishan, Shabari; Chacko, Ari George

2016-12-01

Objective  To describe the technique of endoscopic transmaxillary temporalis muscle flap transposition for the repair of a persistent postoperative sphenoidal cerebrospinal fluid leak. Design  The repair of a recurrent cerebrospinal fluid leak for a patient who had undergone endoscopic transsphenoidal excision of an invasive silent corticotroph Hardy C and Knosp Grade IV pituitary adenoma was undertaken. The patient had completed postoperative radiotherapy for the residual tumor and presented with cerebrospinal fluid leak, 1 year later. The initial two attempts to repair the cerebrospinal fluid leak with free grafts failed. Therefore, an endoscopic transmaxillary transposition of the temporalis muscle flap was attempted to stop the cerebrospinal fluid leak. Results  The endoscopic transmaxillary transposition of the vascularized temporalis muscle flap onto the cerebrospinal fluid leak repair site resulted in successful closure of the cerebrospinal fluid leak. Conclusion  Endoscopic transmaxillary transposition of the temporalis flap resulted in closure of recurrent cerebrospinal fluid leak in a patient with recurrent pituitary adenoma, who had undergone previous surgery and radiotherapy. This technique has advantages over the endoscopic transpterygoid transposition of the same flap and could be used as a complementary technique in selected patients.

Fiber optic distributed chemical sensor for the real time detection of hydrocarbon fuel leaks

NASA Astrophysics Data System (ADS)

Mendoza, Edgar; Kempen, C.; Esterkin, Yan; Sun, Sunjian

2015-09-01

With the increase worldwide demand for hydrocarbon fuels and the vast development of new fuel production and delivery infrastructure installations around the world, there is a growing need for reliable hydrocarbon fuel leak detection technologies to provide safety and reduce environmental risks. Hydrocarbon leaks (gas or liquid) pose an extreme danger and need to be detected very quickly to avoid potential disasters. Gas leaks have the greatest potential for causing damage due to the explosion risk from the dispersion of gas clouds. This paper describes progress towards the development of a fast response, high sensitivity, distributed fiber optic fuel leak detection (HySense™) system based on the use of an optical fiber that uses a hydrocarbon sensitive fluorescent coating to detect the presence of fuel leaks present in close proximity along the length of the sensor fiber. The HySense™ system operates in two modes, leak detection and leak localization, and will trigger an alarm within seconds of exposure contact. The fast and accurate response of the sensor provides reliable fluid leak detection for pipelines, storage tanks, airports, pumps, and valves to detect and minimize any potential catastrophic damage.

Consciousness across Sleep and Wake: Discontinuity and Continuity of Memory Experiences As a Reflection of Consolidation Processes

PubMed Central

Horton, Caroline L.

2017-01-01

The continuity hypothesis (1) posits that there is continuity, of some form, between waking and dreaming mentation. A recent body of work has provided convincing evidence for different aspects of continuity, for instance that some salient experiences from waking life seem to feature in dreams over others, with a particular role for emotional arousal as accompanying these experiences, both during waking and while asleep. However, discontinuities have been somewhat dismissed as being either a product of activation-synthesis, an error within the consciousness binding process during sleep, a methodological anomaly, or simply as yet unexplained. This paper presents an overview of discontinuity within dreaming and waking cognition, arguing that disruptions of consciousness are as common a feature of waking cognition as of dreaming cognition, and that processes of sleep-dependent memory consolidation of autobiographical experiences can in part account for some of the discontinuities of sleeping cognition in a functional way. By drawing upon evidence of the incorporation, fragmentation, and reorganization of memories within dreams, this paper proposes a model of discontinuity whereby the fragmentation of autobiographical and episodic memories during sleep, as part of the consolidation process, render salient aspects of those memories subsequently available for retrieval in isolation from their contextual features. As such discontinuity of consciousness in sleep is functional and normal. PMID:28936183

Preventing a Washout.

ERIC Educational Resources Information Center

Poindexter, Dave

1996-01-01

Offers ideas for locating a roof leak. Discusses why many leaks originate in the roof's base flashings and the importance of knowing the roof's material makeup. Advocates keeping a roof-leak history and gives advice on performing inspections to check for leaks. Discusses how to find small holes in roofs. (RJM)

Anastomotic leaks: what is the best diagnostic imaging study?

PubMed

Nicksa, G A; Dring, R V; Johnson, K H; Sardella, W V; Vignati, P V; Cohen, J L

2007-02-01

Postoperative anastomotic leaks are one of the most devastating consequences of colorectal surgery. Diagnostic imaging for upper gastrointestinal anastomotic leaks has been evaluated and reported on extensively. No study has compared the utility and effectiveness of CT scans and water-soluble enemas for the identification of postoperative lower gastrointestinal anastomotic leaks. The present study was designed to evaluate and compare these two common radiographic imaging modalities in detecting lower gastrointestinal anastomotic leaks. A retrospective chart review was performed that identified 36 patients during a seven-year period who underwent reoperative surgery for a lower gastrointestinal anastomotic leak. Patient's imaging studies were classified as positive if extravasation of contrast material was demonstrated. When negative, a study was retrospectively reviewed in an attempt to identify findings suggestive of an anastomotic leak. There were 36 patients identified with a postoperative lower gastrointestinal leak requiring surgical intervention. There were 28 of 36 patients (78 percent) re-explored on the basis of a radiologic study demonstrating an anastomotic leak. A total of 27 CT scans were performed, of which 4 (14.8 percent) were considered positive for an anastomotic leak. On review of the remaining negative CT scans, nine (33.3 percent) were considered descriptive positive with a large amount of fluid or air in the peritoneal cavity but without obvious extravasation of contrast. Eighteen patients were evaluated with a water-soluble enema and 15 (83.3 percent) demonstrated extravasation of contrast material. In the 26 patients with a distal anastomotic leak, 17 water-soluble enemas were performed, with 15 (88 percent) demonstrating a leak. In contrast, only 2 of 17 (12 percent) CT scans were positive in this group of patients (P < 0.001). There were ten patients who initially had a CT scan followed by a water-soluble enema. Of these patients, eight of nine (88 percent) initially had a negative CT scan but were considered to be clinically suspicious of having an anastomotic leak and subsequently had a leak demonstrated on a water-soluble enema. Early intervention in patients who develop an anastomotic leak can be shown to improve the ultimate outcome, especially with respect to mortality. It is usually necessary to obtain objective tests of anastomotic integrity because of the nonspecificity of clinical signs. Our study supported the superiority of water-soluble enema to CT imaging in patients in whom both modalities were used. This difference was most pronounced for distal anastomotic leaks, whereas no radiologic imaging study proved effective in evaluating proximal anastomoses.

Experiences with leak rate calculations methods for LBB application

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

Grebner, H.; Kastner, W.; Hoefler, A.

1997-04-01

In this paper, three leak rate computer programs for the application of leak before break analysis are described and compared. The programs are compared to each other and to results of an HDR Reactor experiment and two real crack cases. The programs analyzed are PIPELEAK, FLORA, and PICEP. Generally, the different leak rate models are in agreement. To obtain reasonable agreement between measured and calculated leak rates, it was necessary to also use data from detailed crack investigations.

Temporal variation of the leak pressure of uncuffed endotracheal tubes following pediatric intubation: an observational study.

PubMed

Patel, Shreya; Lalwani, Kirk; Koh, Jeffrey; Wu, Lei; Fu, Rongwei

2014-06-01

Uncuffed endotracheal tubes are still preferred over cuffed tubes in certain situations in pediatric anesthesia. Inaccurately sized uncuffed endotracheal tubes may lead to inadequate ventilation or tracheal mucosal damage during anesthesia. Endotracheal tube size in children is usually assessed by measuring the audible leak pressure; if the fit of the tube and the leak pressure decrease significantly with time, reintubation during surgery as a result of inability to ventilate effectively may be challenging, and could lead to patient morbidity. There is no evidence to indicate whether leak pressure increases or decreases with time following endotracheal intubation with uncuffed tubes in children. We measured leak pressure for 30 min following tracheal intubation in 46 ASA I children age 0-7 years after excluding factors known to modify leak pressure. The largest mean change in leak pressure occurred between time points 0 and 15 min, an increase of 3.5 cmH2O. Endotracheal tube size and type of procedure were associated with the leak pressure. In the final linear mixed model, there were no statistically significant variations in leak pressure over time (P = 0.129) in this group of children. We did not identify a consistent change in leak pressure within 30 min following tracheal intubation with uncuffed endotracheal tubes in this group of children.

Recent advances in the treatment of air leaks.

PubMed

Cerfolio, Robert James

2005-07-01

Alveolar-pleural fistulas (air leaks) are an extremely common clinical problem and remain the most common complication after elective pulmonary resection and video-assisted procedures. The decision making process used to manage air leaks and chest tubes that control them has been, until very recently, based on opinions and training preferences as opposed to facts derived from randomized clinical trials. Recently, several prospective randomized trials have studied air leaks. An objective, reproducible classification system has also been designed and clinically validated to help study air leaks. This system and these studies have shown that water seal is superior to wall suction to help stop most leaks. Even in patients with a pneumothorax and an air leak, water seal is safe and best; however, if a patient has a large leak (greater than an expiratory 3 on the classification system) or experiences subcutaneous emphysema or an expanding pneumothorax that causes hypoxia, then some suction (-10 cm of water) should be applied to the chest tubes. Air leaks were a poorly understood yet extremely common clinical problem that had never been scientifically studied. Over the past 5 years, prospective randomized studies have shown that water seal is the best setting for chest tubes and that a pneumothorax is not a contraindication to leaving tubes on seal. Further studies are needed to investigate the ideal management of alveolar-pleural fistulas (air leaks) in different clinical scenarios besides those that occur postoperatively.

The Diagnostic Value of Routine Contrast Esophagram in Anastomotic Leaks After Esophagectomy.

PubMed

Hu, Zhongwu; Wang, Xiaowe; An, Xush; Li, Wenjin; Feng, Yun; You, Zhenbing

2017-08-01

Routine contrast esophagram has been shown to be increasingly limited in diagnosing anastomotic leaks after esophagectomy. Patients undergoing esophagectomy from 2013 to 2014 at Huai'an First Peoples' Hospital were identified. We retrospectively analyzed patients who underwent routine contrast esophagram on postoperative day 7 (range 6-10) to preclude anastomotic leaks after esophagectomy. In 846 patients who underwent esophagectomy, a cervical anastomosis was performed in 286 patients and an intrathoracic anastomosis in 560 patients. There were 57 (6.73%) cases with anastomotic leaks, including cervical leaks in 36 and intrathoracic leaks in 21 patients. In the cervical anastomotic leak patients, 13 were diagnosed by early local clinical symptoms and 23 underwent routine contrast esophagram. There were 7 (30.4%) true-positive, 11 (47.8%) false-negative, and five (21.8%) equivocal cases. In the intrathoracic anastomotic leak patients, four (19%) were diagnosed by clinical symptoms, 16 (76.2%) were true positives, and one (4.8%) was a false negative. Aspiration occurred in five patients with cervical anastomoses and in eight patients with intrathoracic anastomoses; aspiration pneumonitis did not occur in these cases. Gastrografin and barium are safe contrast agents to use in post-esophagectomy contrast esophagram. Because of the low sensitivity in detecting cervical anastomotic leaks, routine contrast esophagram is not advised. For patients with intrathoracic anastomoses, it is still an effective method for detecting anastomotic leaks.

Lymphangiography in the Diagnosis and Localization of Various Chyle Leaks

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

Deso, Steve; Ludwig, Benjamin; Kabutey, Nii-Kabu

2012-02-15

Purpose: Chyle leaks are rare entities infrequently encountered by most physicians. However, large centers providing advanced surgical care are inevitably confronted with chyle leaks as a complication of surgery, an extension of disease, or as a primary disorder. Regardless of the etiology, proper diagnosis and localization are paramount in the management of any chyle leak. Materials and Methods: Here we present 16 patients with 17 chyle leaks (5 chyluria, 8 chylothorax, and 4 chylous ascites) who underwent bipedal lymphangiography (LAG) and postprocedure computed tomography (CT) imaging. Results: In each case, the source of the chyle leak was identified and properlymore » localized to guide further treatment. Of the 16 patients who underwent LAG and postprocedure CT imaging, the initial LAG alone provided the diagnosis and localized the chyle leak in 4 patients (25%); the postprocedure CT imaging provided the diagnosis and localized the chyle leak in 6 patients (37.5%); and the two modalities were equal in the diagnosing and localizing the chyle leak in the remaining 6 patients (37.5%)ConclusionThese cases highlight the unparalleled abilities of LAG and the added benefit of post-LAG CT imaging in the diagnosis and fine anatomic localization of chyle leaks. In addition, these cases demonstrate the retained utility of LAG in these investigations despite the development of alternative tests involving CT, magnetic resonance imaging, and nuclear medicine imaging.« less

Technical factors associated with anastomotic leak after Roux-en-Y gastric bypass.

PubMed

Smith, Mark D; Adeniji, Abidemi; Wahed, Abdus S; Patterson, Emma; Chapman, William; Courcoulas, Anita P; Dakin, Gregory; Flum, David; McCloskey, Carol; Mitchell, James E; Pomp, Alfons; Staten, Myrlene; Wolfe, Bruce

2015-01-01

Anastomotic leak is one of the most serious complications after Roux-en-Y gastric bypass (RYGB). Our objective was to examine the relationship between technical factors and incidence of clinically relevant anastomotic leak after RYGB in longitudinal assessment of bariatric surgery (LABS). The setting of the study was 11 bariatric centers in the United States, university, and private practice. Patient characteristics, technical factors of surgery, and postoperative outcomes were assessed by trained researchers using standardized protocols. Correlation of surgical factors of patients undergoing RYGB (n = 4444) with the incidence of postoperative anastomotic leak was assessed by univariate χ(2) analysis. Forty-four participants (1.0%, 95% CI .7%-1.3%) experienced a clinically relevant anastomotic leak. Of these, 39 (89%) underwent abdominal reoperation and 3 (7%) died. Technical factors associated with anastomotic leak were open surgery (P<.0001), revision surgery (P<.0001), and use of an abdominal drain (P = .02). Provocative leak testing, method of gastrojejunostomy, and use of fibrin sealant were not associated with anastomotic leak. Anastomotic leak after RYGB was rare (1.0%). Most cases required reintervention; however, the majority (93%) recovered from this event. Open surgery, revision surgery, and routine drain placement were associated with increased leak rate. Some of these findings may be due to differences in preoperative patient risk. Copyright © 2015 American Society for Metabolic and Bariatric Surgery. All rights reserved.

Paravalvular Leak in Structural Heart Disease.

PubMed

Goel, Kashish; Eleid, Mackram F

2018-03-06

This review will summarize the growing importance of diagnosing and managing paravalvular leak associated with surgical and transcatheter valves. The burden of paravalvular leak is increasing; however, advanced imaging techniques and high degree of clinical suspicion are required for diagnosis and management. The latest data from pivotal clinical trials in the field of transcatheter aortic valve replacement suggest that any paravalvular leak greater than mild was associated with worse clinical outcomes. Percutaneous techniques for paravalvular leak closure are now the preferred approach, and surgical repair is reserved for contraindications and unsuccessful procedures. Recent data from studies evaluating paravalvular leak closure outcomes report a greater than 90% success rate with a significant improvement in patient symptoms. Paravalvular leak is a growing problem in the structural heart disease arena. Percutaneous closure is successful in more than 90% of the procedures with a low complication rate.

Superfluid helium leak sealant study

NASA Technical Reports Server (NTRS)

Vorreiter, J. W.

1981-01-01

Twenty-one leak specimens were fabricated in the ends of stainless steel and aluminum tubes. Eighteen of these tubes were coated with a copolymer material to seal the leak. The other three specimens were left uncoated and served as control specimens. All 21 tubes were cold shocked in liquid helium 50 times and then the leak rate was measured while the tubes were submerged in superfluid helium at 1.7 K. During the cold shocks two of the coated specimens were mechanically damaged and eliminated from the test program. Of the remaining 16 coated specimens one suffered a total coating failure and resulting high leak rate. Another three of the coated specimens suffered partial coating failures. The leak rates of the uncoated specimens were also measured and reported. The significance of various leak rates is discussed in view of the infrared astronomical satellite (IRAS) Dewar performance.

[Water-cooled laser sealing of lung tissue in an ex-vivo ventilated porcine lung model].

PubMed

Tonoyan, T; Prisadov, G; Menges, P; Herrmann, K; Bobrov, P; Linder, A

2014-06-01

Laser resections of lung metastases are followed by air leaks from the parenchymal defect. Large surfaces after metastasectomy are closed by sutures or sealants while smaller areas are frequently sealed thermally by cautery or laser. In this study two different techniques of thermal sealing of lung tissue with laser light are investigated. Carbonisation of lung tissue during thermal sealing appears at temperatures higher than 180 °C. Hypothetically this is contraproductive to haemo- as well as to pneumostasis. In this experimental study thermal laser sealing with and without carbonisation is investigated. In one series tissue temperatures higher than 100 °C are avoided by water dropping from the tip of the light guide onto the parenchymal leak. In the other series carbonisation appeared because the laser light was applied in the non-contact mode without tissue cooling. The characteristics of the laser were 40 W, 1350 nm continuous mode. Air leaks (Vt) were measured with a simple and fast technique with high precision. The sealing effect of either series was defined as S = (1-Vt/V0) and the difference of S was statistically examined. The basic values V0 before sealing were about the same in both series. The air leaks Vt after 15, 30 and 45 s of sealing varied significantly in both series (p = 0.03). During simultaneous cooling the sealing effect was increasing with the duration of laser application, while it became worse in the series without cooling. Histological examination of the sealing zone showed only coagulation of the tissue, while ruptured alveolae could be seen more often in the non-cooled sealing area. It could be shown in the ex-vivo lung model that laser sealing of parenchymal leaks is improved by simultaneous cooling during laser application. Non cooled laser sealing seems to heat up the tissue abruptly and create carbonisation followed by multiple ruptures of alveola and small airways. In accordance with our clinical experience this experimental study confirms that laser sealing for pneumostasis after metastasectomy can be improved by simultaneously cooling the resection area when treated with the laser. Georg Thieme Verlag KG Stuttgart · New York.

Phosphatidylserine containing omega-3 Fatty acids may improve memory abilities in nondemented elderly individuals with memory complaints: results from an open-label extension study.

PubMed

Vakhapova, Veronika; Cohen, Tzafra; Richter, Yael; Herzog, Yael; Kam, Yossi; Korczyn, Amos D

2014-01-01

The present study is an open-label extension (OLE) aimed at evaluating the effect of 100 mg/day of phosphatidylserine enriched with docosahexaenoic acid (PS-DHA) on cognitive performance in nondemented elderly individuals with memory complaints. From the participants who completed the core study, 122 continued with a 15-week OLE. Efficacy was assessed using a computerized tool and the Clinical Global Impression of Change (CGI-C) rating scale. A significant improvement in sustained attention and memory recognition was observed in the PS-DHA naïve group, while the PS-DHA continuers maintained their cognitive status. Additionally, a significant improvement in CGI-C was observed in the naïve group. The results demonstrate that consumption of 100 mg/day of PS-DHA might be associated with improving or maintaining cognitive status in elderly subjects with memory complaints.

A multicenter study of routine versus selective intraoperative leak testing for sleeve gastrectomy.

PubMed

Bingham, Jason; Kaufman, Jedediah; Hata, Kai; Dickerson, James; Beekley, Alec; Wisbach, Gordon; Swann, Jacob; Ahnfeldt, Eric; Hawkins, Devon; Choi, Yong; Lim, Robert; Martin, Matthew

2017-09-01

Staple line leaks after sleeve gastrectomy are dreaded complications. Many surgeons routinely perform an intraoperative leak test (IOLT) despite little evidence to validate the reliability, clinical benefit, and safety of this procedure. To determine the efficacy of IOLT and if routine use has any benefit over selective use. Eight teaching hospitals, including private, university, and military facilities. A multicenter, retrospective analysis over a 5-year period. The efficacy of the IOLT for identifying unsuspected staple line defects and for predicting postoperative leaks was evaluated. An anonymous survey was also collected reflecting surgeons' practices and beliefs regarding IOLT. From January 2010 through December 2014, 4284 patients underwent sleeve gastrectomy. Of these, 37 patients (.9%) developed a postoperative leak, and 2376 patients (55%) received an IOLT. Only 2 patients (0.08%) had a positive finding. Subsequently, 21 patients with a negative IOLT developed a leak. IOLT demonstrated a sensitivity of only 8.7%. There was a nonsignificant trend toward increased leak rates when an IOLT was performed versus when IOLT was not performed. Leak rates were not statistically different between centers that routinely perform IOLT versus those that selectively perform IOLT. Routine IOLT had very poor sensitivity and was negative in 91% of patients who later developed postoperative leaks. The use of IOLT was not associated with a decrease in the incidence of postoperative leaks, and routine IOLT had no benefit over selective leak testing. IOLT should not be used as a quality indicator or "best practice" for bariatric surgery. Published by Elsevier Inc.

Ultrafast dynamic computed tomography myelography for the precise identification of high-flow cerebrospinal fluid leaks caused by spiculated spinal osteophytes.

PubMed

Thielen, Kent R; Sillery, John C; Morris, Jonathan M; Hoxworth, Joseph M; Diehn, Felix E; Wald, John T; Rosebrock, Richard E; Yu, Lifeng; Luetmer, Patrick H

2015-03-01

Precise localization and understanding of the origin of spontaneous high-flow spinal CSF leaks is required prior to targeted treatment. This study demonstrates the utility of ultrafast dynamic CT myelography for the precise localization of high-flow CSF leaks caused by spiculated spinal osteophytes. This study reports a series of 14 patients with high-flow CSF leaks caused by spiculated spinal osteophytes who underwent ultrafast dynamic CT myelography between March 2009 and December 2010. There were 10 male and 4 female patients, with an average age of 49 years (range 37-74 years). The value of ultrafast dynamic CT myelography in depicting the CSF leak site was qualitatively assessed. In all 14 patients, ultrafast dynamic CT myelography was technically successful at precisely demonstrating the site of the CSF leak, the causative spiculated osteophyte piercing the dura, and the relationship of the implicated osteophyte to adjacent structures. Leak sites included 3 cervical, 11 thoracic, and 0 lumbar levels, with 86% of the leaks occurring from C-5 to T-7. Information obtained from the ultrafast dynamic CT myelogram was considered useful in all treated CSF leaks. Spinal osteophytes piercing the dura are a more frequent cause of high-flow CSF leaks than previously recognized. Ultrafast dynamic CT myelography adds value beyond standard dynamic myelography or digital subtraction myelography in the diagnosis and anatomical characterization of high-flow spinal CSF leaks caused by these osteophytes. This information allows for appropriate planning for percutaneous or surgical treatment.

Assessing Surgeon Behavior Change after Anastomotic Leak in Colorectal Surgery

PubMed Central

Simianu, Vlad V.; Basu, Anirban; Alfonso-Cristancho, Rafael; Thirlby, Richard C.; Flaxman, Abraham D.; Flum, David R.

2016-01-01

Background Recency effect suggests that people disproportionately value events from the immediate past when making decisions, but the extent of this impact on surgeons’ decisions is unknown. This study evaluates for recency effect in surgeons by examining use of preventative leak testing before and after colorectal operations with anastomotic leaks. Materials and Methods Prospective cohort of adult patients (≥18 years) undergoing elective colorectal operations at Washington State hospitals participating in the Surgical Care and Outcomes Assessment Program (2006–2013). The main outcome measure was surgeons’ change in leak testing from 6 months before to 6 months after an anastomotic leak occurred. Results Across 4,854 elective colorectal operations performed by 282 surgeons at 44 hospitals, there was a leak rate of 2.6% (n=124). The 40 leaks (32%) in which the anastomosis was not tested occurred across 25 surgeons. While the ability to detect an overall difference in use of leak testing was limited by small sample size, 9 (36%) of 25 surgeons increased their leak testing by 5 percent points or more after leaks in cases where the anastomosis was not tested. Surgeons who increased their leak testing more frequently performed operations for diverticulitis (45% vs 33%), more frequently began their cases laparoscopically (65% vs 37%), and had longer mean operative times (195±99 vs 148±87 minutes), all p<0.001. Conclusions Recency effect was demonstrated by only one-third of eligible surgeons. Understanding the extent to which clinical decisions may be influenced by recency effect may be important in crafting quality improvement initiatives that require clinician behavior change. PMID:27664886

Ultrasonic Detectors Safely Identify Dangerous, Costly Leaks

NASA Technical Reports Server (NTRS)

2013-01-01

In 1990, NASA grounded its space shuttle fleet. The reason: leaks detected in the hydrogen fuel systems of the Space Shuttles Atlantis and Columbia. Unless the sources of the leaks could be identified and fixed, the shuttles would not be safe to fly. To help locate the existing leaks and check for others, Kennedy Space Center engineers used portable ultrasonic detectors to scan the fuel systems. As a gas or liquid escapes from a leak, the resulting turbulence creates ultrasonic noise, explains Gary Mohr, president of Elmsford, New York-based UE Systems Inc., a long-time leader in ultrasonic detector technologies. "In lay terms, the leak is like a dog whistle, and the detector is like the dog ear." Because the ultrasound emissions from a leak are highly localized, they can be used not only to identify the presence of a leak but also to help pinpoint a leak s location. The NASA engineers employed UE s detectors to examine the shuttle fuel tanks and solid rocket boosters, but encountered difficulty with the devices limited range-certain areas of the shuttle proved difficult or unsafe to scan up close. To remedy the problem, the engineers created a long-range attachment for the detectors, similar to "a zoom lens on a camera," Mohr says. "If you are on the ground, and the leak is 50 feet away, the detector would now give you the same impression as if you were only 25 feet away." The enhancement also had the effect of reducing background noise, allowing for a clearer, more precise detection of a leak s location.

40 CFR 63.11583 - What are my monitoring requirements?

Code of Federal Regulations, 2010 CFR

2010-07-01

... preparation operation are in target HAP service: (a) Operate a bag leak detection system with alarm that will alert operators of a leak in the control device filter material. If a bag leak detection system with... install, calibrate, operate, and maintain each bag leak detection system and alarm according to...

40 CFR 63.424 - Standards: Equipment leaks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Equipment leaks. 63.424....424 Standards: Equipment leaks. (a) Each owner or operator of a bulk gasoline terminal or pipeline breakout station subject to the provisions of this subpart shall perform a monthly leak inspection of all...

PORTABLE IMAGING DEVICES FOR INDUSTRIAL LEAK DETECTION AT PETROLEUM REFINERIES AND CHEMICAL PLANTS

EPA Science Inventory

Undiscovered gas leaks, or fugitive emissions, in chemical plants and refinery operations can impact regional air quality as well as being a public health problem. Surveying a facility for potential gas leaks can be a daunting task. Industrial Leak Detection and Repair (LDAR) pro...

40 CFR 63.986 - Nonflare control devices used for equipment leaks only.

Code of Federal Regulations, 2010 CFR

2010-07-01

... equipment leaks only. 63.986 Section 63.986 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... leaks only. (a) Equipment and operating requirements. (1) Owners or operators using a nonflare control device to meet the applicable requirements of a referencing subpart for equipment leaks shall meet the...

40 CFR 63.691 - Standards: Equipment leaks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Standards: Equipment leaks. 63.691....691 Standards: Equipment leaks. (a) The provisions of this section apply to the control of air emissions from equipment leaks for which § 63.683(d) references the use of this section for such air...

Hanford Double-Shell Tank AY-102 Radioactive Waste Leak Investigation Update

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

Washenfelder, Dennis J.

2015-02-03

The presentation outline is: Briefly review leak integrity status of tank AY-102 and current leak behavior; Summarize recent initiatives to understand leak mechanism and to verify integrity of remaining waste confinement structures; describe planned waste recovery activities; and, introduce other papers on tank AY-102 topics.

Conceptual apparatus for detecting leaks of nonconductive liquids

NASA Technical Reports Server (NTRS)

Walsh, G. D.

1968-01-01

Apparatus detects leaks at joints in lines carrying electrically nonconductive liquids. The proposed apparatus could include a panel that would give a visual or audible indication of a leak /to permit manual shutdown/ and/or an electromechanical actuator that would automatically cut off the flow when a leak occurs.

40 CFR 63.1005 - Leak repair.

Code of Federal Regulations, 2013 CFR

2013-07-01

... lubricant into the lubricated packing. (b) Leak identification removal—(1) Valves in gas/vapor and light liquid service. The leak identification on a valve in gas/vapor or light liquid service may be removed... monitoring. The leak identification on a connector in gas/vapor or light liquid service may be removed after...

40 CFR 63.1005 - Leak repair.

Code of Federal Regulations, 2012 CFR

2012-07-01

... lubricant into the lubricated packing. (b) Leak identification removal—(1) Valves in gas/vapor and light liquid service. The leak identification on a valve in gas/vapor or light liquid service may be removed... monitoring. The leak identification on a connector in gas/vapor or light liquid service may be removed after...

40 CFR 63.1005 - Leak repair.

Code of Federal Regulations, 2011 CFR

2011-07-01

... lubricant into the lubricated packing. (b) Leak identification removal—(1) Valves in gas/vapor and light liquid service. The leak identification on a valve in gas/vapor or light liquid service may be removed... monitoring. The leak identification on a connector in gas/vapor or light liquid service may be removed after...

40 CFR 63.1005 - Leak repair.

Code of Federal Regulations, 2014 CFR

2014-07-01

... lubricant into the lubricated packing. (b) Leak identification removal—(1) Valves in gas/vapor and light liquid service. The leak identification on a valve in gas/vapor or light liquid service may be removed... monitoring. The leak identification on a connector in gas/vapor or light liquid service may be removed after...

Sensitivities of Soap Solutions in Leak Detection

NASA Technical Reports Server (NTRS)

Stuck, D.; Lam, D. Q.; Daniels, C.

1985-01-01

Document describes method for determining minimum leak rate to which soap-solution leak detectors sensitive. Bubbles formed at smaller leak rates than previously assumed. In addition to presenting test results, document discusses effects of joint-flange configurations, properties of soap solutions, and correlation of test results with earlier data.

Hippocampal-targeted Theta-burst Stimulation Enhances Associative Memory Formation.

PubMed

Tambini, Arielle; Nee, Derek Evan; D'Esposito, Mark

2018-06-19

The hippocampus plays a critical role in episodic memory, among other cognitive functions. However, few tools exist to causally manipulate hippocampal function in healthy human participants. Recent work has targeted hippocampal-cortical networks by performing TMS to a region interconnected with the hippocampus, posterior inferior parietal cortex (pIPC). Such hippocampal-targeted TMS enhances associative memory and influences hippocampal functional connectivity. However, it is currently unknown which stages of mnemonic processing (encoding or retrieval) are affected by hippocampal-targeted TMS. Here, we examined whether hippocampal-targeted TMS influences the initial encoding of associations (vs. items) into memory. To selectively influence encoding and not retrieval, we performed continuous theta-burst TMS before participants encoded object-location associations and assessed memory after the direct effect of stimulation dissipated. Relative to control TMS and baseline memory, pIPC TMS enhanced associative memory success and confidence. Item memory was unaffected, demonstrating a selective influence on associative versus item memory. The strength of hippocampal-pIPC functional connectivity predicted TMS-related memory benefits, which was mediated by parahippocampal and retrosplenial cortices. Our findings indicate that hippocampal-targeted TMS can specifically modulate the encoding of new associations into memory without directly influencing retrieval processes and suggest that the ability to influence associative memory may be related to the fidelity of hippocampal TMS targeting. Our results support the notion that pIPC TMS may serve as a potential tool for manipulating hippocampal function in healthy participants. Nonetheless, future work combining hippocampal-targeted continuous theta-burst TMS with neuroimaging is needed to better understand the neural basis of TMS-induced memory changes.

Influence of mouth opening on oropharyngeal humidification and temperature in a bench model of neonatal continuous positive airway pressure.

PubMed

Fischer, Hendrik S; Ullrich, Tim L; Bührer, Christoph; Czernik, Christoph; Schmalisch, Gerd

2017-02-01

Clinical studies show that non-invasive respiratory support by continuous positive airway pressure (CPAP) affects gas conditioning in the upper airways, especially in the presence of mouth leaks. Using a new bench model of neonatal CPAP, we investigated the influence of mouth opening on oropharyngeal temperature and humidity. The model features the insertion of a heated humidifier between an active model lung and an oropharyngeal head model to simulate the recurrent expiration of heated, humidified air. During unsupported breathing, physiological temperature and humidity were attained inside the model oropharynx, and mouth opening had no significant effect on oropharyngeal temperature and humidity. During binasal CPAP, the impact of mouth opening was investigated using three different scenarios: no conditioning in the CPAP circuit, heating only, and heated humidification. Mouth opening had a strong negative impact on oropharyngeal humidification in all tested scenarios, but heated humidification in the CPAP circuit maintained clinically acceptable humidity levels regardless of closed or open mouths. The model can be used to test new equipment for use with CPAP, and to investigate the effects of other methods of non-invasive respiratory support on gas conditioning in the presence of leaks. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

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

James K. Neathery; Gary Jacobs; Amitava Sarkar

In the previous reporting period, modifications were completed for integrating a continuous wax filtration system for a 4 liter slurry bubble column reactor. During the current reporting period, a shakedown of the system was completed. Several problems were encountered with the progressive cavity pump used to circulate the wax/catalyst slurry though the cross-flow filter element and reactor. During the activation of the catalyst with elevated temperature (> 270 C) the elastomer pump stator released sulfur thereby totally deactivating the iron-based catalyst. Difficulties in maintaining an acceptable leak rate from the pump seal and stator housing were also encountered. Consequently, themore » system leak rate exceeded the expected production rate of wax; therefore, no online filtration could be accomplished. Work continued regarding the characterization of ultra-fine catalyst structures. The effect of carbidation on the morphology of iron hydroxide oxide particles was the focus of the study during this reporting period. Oxidation of Fe (II) sulfate results in predominantly {gamma}-FeOOH particles which have a rod-shaped (nano-needles) crystalline structure. Carbidation of the prepared {gamma}-FeOOH with CO at atmospheric pressure produced iron carbides with spherical layered structure. HRTEM and EDS analysis revealed that carbidation of {gamma}-FeOOH particles changes the initial nano-needles morphology and generates ultrafine carbide particles with irregular spherical shape.« less

Individual Differences in Working Memory Capacity and Episodic Retrieval: Examining the Dynamics of Delayed and Continuous Distractor Free Recall

ERIC Educational Resources Information Center

Unsworth, Nash

2007-01-01

Two experiments explored the possibility that individual differences in working memory capacity (WMC) partially reflect differences in the size of the search set from which items are retrieved. High- and low-WMC individuals were tested in delayed (Experiment 1) and continuous distractor (Experiment 2) free recall with varying list lengths. Across…

Insight into the Effects of Reinforcement Shape on Achieving Continuous Martensite Transformation in Phase Transforming Matrix Composites

NASA Astrophysics Data System (ADS)

Zhang, Xudong; Ren, Junqiang; Wang, Xiaofei; Zong, Hongxiang; Cui, Lishan; Ding, Xiangdong

2017-12-01

A continuous martensite transformation is indispensable for achieving large linear superelasticity and low modulus in phase transforming metal-based composites. However, determining how to accurately condition the residual martensite in a shape memory alloy matrix though the reinforcement shape to achieve continuous martensite transformation has been a challenge. Here, we take the finite element method to perform a comparative study of the effects of nanoinclusion shape on the interaction and martensite phase transformation in this new composite. Two typical samples are compared: one reinforced by metallic nanowires and the other by nanoparticles. We find that the residual martensite within the shape memory alloy matrix after a pretreatment can be tailored by the reinforcement shape. In particular, our results show that the shape memory alloy matrix can retain enough residual martensite phases to achieve continuous martensite transformation in the subsequent loading when the aspect ratio of nanoreinforcement is larger than 20. In contrast, the composites reinforced with spherical or low aspect ratio reinforcement show a typical nonlinear superelasticity as a result of a low stress transfer-induced discontinuous martensite transformation within the shape memory alloy matrix.

Fluid leak indicator

NASA Technical Reports Server (NTRS)

Anderson, G. E.; Loo, S. (Inventor)

1985-01-01

A fluid leak indicator for detecting and indicating leaks in visually inaccessible fluid tubing joints, such as those obstructed by insulation includes a bag system and a wicking system surrounding or wrapping the joints under the visual obstructing material. Leaking fluid is collected in the bag or on the wicking material where it is conducted along the wicking material to a visily accessible capturing transparent indicator bulb for providing a visual indication of the leak without requiring a chemical change in the capturing indicator bulb.

High sensitivity leak detection method and apparatus

DOEpatents

Myneni, Ganapatic R.

1994-01-01

An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.