Diffusion and Wall Loss of Magnesium in Decaying Plasma

1999 ◽  
pp. 497-498
Author(s):  
I. Rusinov ◽  
A. Blagoev ◽  
M. Pentcheva ◽  
V. Yordanov
Keyword(s):  
Wall Loss

Guided Wave Testing: Maximizing Buried Pipe Corrosion Knowledge From Each Excavation

2012 ◽  
Author(s):  
Andy Crompton ◽  
Roger Royer ◽  
Mark Tallon ◽  
Stephen F. Biagiotti
Keyword(s):  
Guided Wave ◽  
Piping System ◽  
Case Histories ◽  
Direct Examination ◽  
Buried Pipe ◽  
Industry Standard ◽  
Limited Effectiveness ◽  
Wall Loss ◽  
Assurance Process ◽  
Non Destructive

Excavation and Direct Examination of buried piping using conventional non-destructive examination (NDE) has been the traditional inspection approach for decades and remains the only quantitative method for piping evaluations in plants when internal in-line inspection tools cannot be used due to geometry or other constraints. This “difficult to assess” piping presents many challenges, including limited effectiveness of traditional indirect inspection tools, high cost and operational concerns associated with excavations, and the ability to evaluate only a small sampling of a piping system. Many inspection technologies exist for buried pipe assessments; however, no indirect techniques provide the ability to yield quantitative wall loss values suitable for ASME fitness for service calculations beyond what’s exposed in the excavation. An evolving technology, guided wave testing (GWT), has many applications including the ability to provide assessment information beyond the excavation. In this paper, the application of GWT for buried piping inspection will be discussed. We will review: principles behind its operation; the competitive technologies on the market; challenges for the technology; management of data within the Electric Power Research Institute (EPRI) industry standard buried pipe database (BPWorks™ 2.0); trending; case histories showing how GWT can be used to extend the knowledge gained during an excavation by screening adjacent areas for more significant corrosion than observed in the excavated and exposed area; coupling GWT results with other inspection technologies to gain an enhanced interpretation of the overall condition of the line; and how to incorporate this data into an effective structural and/or leakage integrity program as part of the reasonable assurance process.

Nondestructive Evaluation for Duplex Stainless Steel Tube Using Multi-Frequencies Remote Field Testing

2015 ◽  
Vol 659 ◽  
pp. 633-637
Author(s):  
Cherdpong Jomdecha ◽  
Isaratat Phung-On ◽  
Kasemsak Sritarathorn
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Eddy Current ◽  
Field Testing ◽  
Steel Tube ◽  
Stainless Steel Tube ◽  
Frequency Range ◽  
Testing Frequency ◽  
Wall Loss ◽  
Different Depths

This paper presents the determination of Remote Field Testing (RFT) frequencies to accomplish the inspection of duplex stainless steel tubes grade ASME/ASTM SA 789. The tube specimen was 25.4 mm of outside diameter, and thickness of 1.65 mm with the different artificial flaws. A dual-pickup coils type of RFT probe was employed to inspect the specimen by inserting a probe within the tube. Optimum of testing frequency Range was determined based on an eddy current through transmission generation to produce different magnetic field density. RFT inspection frequency range for duplex stainless steel was consequently determined from 5 to 25 kHz which was different than those inspection frequencies of general ferromagnetic steel tube. In the experiment, calculated frequencies were then generated to the Eddy current (ET) and RFT probes for detecting the flaws of the tube specimen. The inspection signals were specifically shown in function of impedance plane to identify the flaw characters. The results showed that the RFT can be utilized to quantify the wall loss levels of duplex stainless-steel tube better than the ET. Especially, phase angle of inspection signals can be used to evaluate the different depths of the wall losses. Sensitivity of RFT showed the detection performance at minimum 20% of tube wall loss.

scholarly journals Particle wall-loss correction methods in smog chamber experiments

2018 ◽  
Vol 11 (12) ◽  
pp. 6577-6588 ◽  
Author(s):  
Ningxin Wang ◽  
Spiro D. Jorga ◽  
Jeffery R. Pierce ◽  
Neil M. Donahue ◽  
Spyros N. Pandis
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Rate Constant ◽  
Loss Rate ◽  
Correction Method ◽  
Seed Loss ◽  
Quantification Analysis ◽  
Wall Loss ◽  
Loss Rates

Abstract. The interaction of particles with the chamber walls has been a significant source of uncertainty when analyzing results of secondary organic aerosol (SOA) formation experiments performed in Teflon chambers. A number of particle wall-loss correction methods have been proposed including the use of a size-independent loss rate constant, the ratio of suspended organic mass to that of a conserved tracer (e.g., sulfate seeds), and a size-dependent loss rate constant, etc. For complex experiments such as the chemical aging of SOA, the results of the SOA quantification analysis can be quite sensitive to the adopted correction method due to the evolution of the particle size distribution and the duration of these experiments. We evaluated the performance of several particle wall-loss correction methods for aging experiments of α-pinene ozonolysis products. Determining the loss rates from seed loss periods is necessary for this system because it is not clear when chemical reactions have been completed. Results from the OA ∕ sulfate ratio and the size-independent correction methods can be influenced significantly by the size dependence of the particle wall-loss process. Coagulation can also affect the particle size distribution, especially for particles with diameter less than 100 nm, thus introducing errors in the results of the wall-loss correction. The corresponding loss rate constants may vary from experiment to experiment, and even during a specific experiment. Friction between the Teflon chamber walls and non-conductive surfaces can significantly increase particle wall-loss rates and the chamber may require weeks to recover to its original condition. Experimental procedures are proposed for the characterization of particle losses during different stages of these experiments and the evaluation of corresponding particle wall-loss correction.

Finite element modeling of wall-loss sizing in a steam generator tube using a pulsed eddy current probe

2015 ◽  
Author(s):  
V. K. Babbar ◽  
B. Lepine ◽  
J. Buck ◽  
P. R. Underhill ◽  
J. Morelli ◽  
...  
Keyword(s):  
Finite Element ◽  
Finite Element Modeling ◽  
Steam Generator ◽  
Eddy Current ◽  
Steam Generator Tube ◽  
Element Modeling ◽  
Pulsed Eddy Current ◽  
Wall Loss

scholarly journals Temperature-dependent diffusion coefficient of H<sub>2</sub>SO<sub>4</sub> in air: laboratory measurements using laminar flow technique

2016 ◽  
Author(s):  
David Brus ◽  
Lenka Skrabalova ◽  
Erik Herrmann ◽  
Tinja Olenius ◽  
Tereza Travnickova ◽  
...  
Keyword(s):  
Diffusion Coefficient ◽  
Sulfuric Acid ◽  
Relative Humidity ◽  
Laminar Flow ◽  
Diffusion Coefficients ◽  
Loss Rate ◽  
Rate Coefficients ◽  
Flow Conditions ◽  
Flow Tube ◽  
Wall Loss

Abstract. We report measurements of the diffusion coefficient of sulfuric acid in humidified air at a range of relative humidities (from ~4 to 70 %), temperatures (278, 288 and 298 K) and initial H2SO4 concentration (from 1 × 10e6 to 1 × 10e8 molec. cm−3). The diffusion coefficients were estimated from the sulfuric acid wall loss rate coefficients under laminar flow conditions. The flow conditions were verified with additional fluid dynamics model CFD-FLUENT simulations which also reproduced the loss rate coefficients very well at all three temperatures with the maximum difference of 7 % between the measured and simulated values. The concentration of H2SO4 was measured continuously with chemical ionization mass spectrometer (CIMS) at seven different positions along the flow tube. The wall losses of H2SO4 were determined from the slopes of fits to measured H2SO4 concentrations as a function of the position along the flow tube. The observed wall loss rate coefficients, and hence the diffusion coefficients, were independent of different initial H2SO4 concentrations and different total flow rates. However, the determined diffusion coefficients decreased with increasing relative humidity, as also seen in previous experiments, and had a rather strong power dependence of the diffusion coefficient with respect to temperature, around ∝T5.4, which is in disagreement with the expected temperature dependency of ~T1.75 observed for other gases and not tested before for sulfuric acid. The effect of relative humidity on the diffusion coefficient is likely due to stronger hydration of H2SO4 molecules and likely also due to the presence of trace impurities such as amines, possibly brought to the system by humidification. Clustering kinetics simulations using quantum chemical data suggest that also the strong temperature dependence of the observed diffusion coefficient might be explained by increased diffusion volume of H2SO4 molecules due to stronger clustering with base-impurities like amines.

Tracerco Discovery: the world's first subsea computed tomography (CT) scanner for non-intrusive pipeline inspection

2014 ◽  
Vol 54 (2) ◽  
pp. 545
Author(s):  
Lee Robins
Keyword(s):  
High Resolution ◽  
Wall Thickness ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Ct Scanner ◽  
Remotely Operated Vehicle ◽  
Gas Industry ◽  
Pipeline Inspection ◽  
Non Invasive ◽  
Wall Loss

Tracerco Discovery is the world’s first subsea CT scanner, providing high-resolution wall integrity data plus detection of hydrates and other deposits for flow assurance purposes. It is deployed as a remotely operated vehicle (ROV) and the inspection is carried out from the outside of the pipeline. It is the only non-invasive technology capable of inspecting unpiggable coated pipelines and there is no need to remove and replace the pipe’s protective coating. Unpiggable pipelines, especially coated ones, have proven extremely difficult (and in most cases impossible) to inspect for integrity and wall loss issues. An externally deployed tool to do this is needed by the global pipeline industry. Gas hydrates and other pipeline deposits pose a large challenge for the oil and gas industry as they can form restrictions that can result in costly shutdowns and serious safety threats. It is, therefore, important to be able to locate such restrictions subsea with high accuracy to allow safe and efficient remediation operations. Discovery benefits: Production can continue and normal operations are not affected. A high-resolution tomographic image of wall thickness and pipe contents at each scanning location is provided to 2 mm resolution. Coating does not need to be removed. Suitable for gas, liquid, or multiphase flow. Suitable for rigid and flexible lines. Pipe-in-Pipe lines and pipe-bundles can be inspected to measure the wall thickness of outer and inner pipes. The presentation of this extended abstract covers the background of the development work, gives a description of the technology, and shows recent results.

Optical Coarse Droplet Measurement and Wet Loss Analysis on the Wet Air Flow Through the Subsonic Blade Cascade Channel

2019 ◽  
Author(s):  
Yasuhiro Sasao ◽  
Ryo Takata ◽  
Satoshi Miyake ◽  
Soichiro Tabata ◽  
Satoru Yamamoto
Keyword(s):  
Air Flow ◽  
Loss Analysis ◽  
Subsonic Wind Tunnel ◽  
Water Films ◽  
Passage Vortex ◽  
Blade Row ◽  
Flow Loss ◽  
Wall Loss ◽  
Flow Through ◽  
End Wall

Abstract In order to understand the details of the mechanism of the occurrence of wetness loss between blade rows, the blades of an HP nuclear turbine were modeled in an atmospheric subsonic wind tunnel, and a flow field with wet loss was analyzed in its totality using a three-hole Pitot tube and Phase Doppler Particle Analyzer (PDPA) system. In the secondary flow loss region and the end wall loss region, a significant increase in pressure loss was confirmed under wet conditions. Analysis by measurement and the Eulerian-Lagrangian coupled solver showed that these loss increases can occur due to the agitation of water droplets and water films in the passage vortex or corner vortex. Finally, this report contains a breakdown of profile loss, thermodynamic loss and acceleration loss of the wet air flow through the sub-sonic blade row.

scholarly journals Cyclic AMP enhances the sexual agglutinability of Chlamydomonas flagella.

1989 ◽  
Vol 109 (1) ◽  
pp. 247-252 ◽  
Author(s):  
U W Goodenough
Keyword(s):  
Cell Wall ◽  
Cyclic Amp ◽  
Mating Type ◽  
Feedback System ◽  
Intracellular Camp ◽  
Camp Generation ◽  
Sexual Agglutinability ◽  
Single Mating ◽  
Wall Loss ◽  
Camp Levels

Sexual adhesion between Chlamydomonas reinhardtii gametes elicits a rise in intracellular cAMP levels, and exogenous elevation of intracellular cAMP levels in gametes of a single mating type induces such mating responses as cell wall loss, flagellar tip activation, and mating structure activation (Pasquale, S. M., and U. W. Goodenough. 1987. J. Cell Biol. 105:2279-2292). Here evidence is presented that sexual adhesion mobilizes agglutinin to the flagellar surface, and that this mobilization can be induced by exogenous presentation of cAMP to gametes of a single mating type. It is proposed that Chlamydomonas adhesion entails a positive feedback system--initial contacts stimulate the presentation of additional agglutinin--and that this feedback is mediated by adhesion-induced cAMP generation.

Case Studies of Pulsed Eddy Current to Measure Wall Loss in Feedwater Piping and Heater Shells

2008 ◽  
Author(s):  
Marvin J. Cohn ◽  
Jordan W. Norton
Keyword(s):  
Eddy Current ◽  
Power Plants ◽  
Cost Effective ◽  
Nuclear Industry ◽  
Accelerated Corrosion ◽  
Pulsed Eddy Current ◽  
Catastrophic Failures ◽  
Recent Developments ◽  
Wall Loss ◽  
Flow Accelerated Corrosion

There have been several feedwater piping and heater shell failures in power plants caused by flow-accelerated corrosion (FAC). This failure mechanism may be one of the most important types of damage to find proactively because FAC damage has occasionally resulted in catastrophic failures and human fatalities. Predicting, detecting, and resolving significant FAC damage can significantly reduce future forced outages and increase personnel safety. This paper describes the implementation of recent developments to perform cost-effective FAC examinations. These advances include the use of specialized pulsed eddy current (PEC) hardware and software to scan for wall thinning without removing insulation. Recent results are based on the current version, MK II, of this equipment. The authors have performed more than 200 power plant projects with this PEC equipment, examining numerous pipes and shells. This work consists of more than 70 projects of wall loss examinations for the nuclear industry, including examinations of feedwater heater shells inside the condenser. Results of wall loss measurements regarding PEC average wall thickness (AWT) measurements, ultrasonic thickness examinations (UTTH), and the PEC evaluated Defect Algorithm are compared in this study.

TOF-FS: a technique for detection and monitoring of wall loss defects in large areas of vessels and pipework

2008 ◽  
Vol 50 (9) ◽  
pp. 476-479
Author(s):  
S Terpstra ◽  
F Hoeve ◽  
Z McCann ◽  
M Stone
Keyword(s):  
Wall Loss
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