Science.gov

Sample records for accelerates corrosion problems

  1. Report on accelerated corrosion studies.

    SciTech Connect

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  2. Accelerated Stress-Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Test procedures for accelerated stress-corrosion testing of high-strength aluminum alloys faster and provide more quantitative information than traditional pass/fail tests. Method uses data from tests on specimen sets exposed to corrosive environment at several levels of applied static tensile stress for selected exposure times then subsequently tensile tested to failure. Method potentially applicable to other degrading phenomena (such as fatigue, corrosion fatigue, fretting, wear, and creep) that promote development and growth of cracklike flaws within material.

  3. Corrosion Problems in Absorption Chillers

    ERIC Educational Resources Information Center

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  4. Development of an artificial climatic complex accelerated corrosion tester and investigation of complex accelerated corrosion test methods

    SciTech Connect

    Li, J.; Li, M.; Sun, Z. )

    1999-05-01

    During recent decades, accelerated corrosion test equipment and methods simulating atmospheric corrosion have been developed to incorporate the many factors involved in complex accelerated corrosion. A new accelerated corrosion tester was developed to simulate various kinds of atmospheric corrosion environments. The equipment can be used to simulate various types of atmospheric corrosion environments with up to eight factors and can be used to carry out 18 kinds of standard corrosion and environmental tasks.

  5. Corrosion problems in light water nuclear reactors

    SciTech Connect

    Berry, W.E.

    1984-06-01

    The corrosion problems encountered during the author's career are reviewed. Attention is given to the development of Zircaloys and attendant factors that affect corrosion; the caustic and chloride stress corrosion cracking (SCC) of austenitic stainless steel steam generator tubing; the qualification of Inconel Alloy 600 for steam generator tubing and the subsequent corrosion problem of secondary side wastage, caustic SCC, pitting, intergranular attack, denting, and primary side SCC; and SCC in weld and furnace sensitized stainless steel piping and internals in boiling water reactor primary coolants. Also mentioned are corrosion of metallic uranium alloy fuels; corrosion of aluminum and niobium candidate fuel element claddings; crevice corrosion and seizing of stainless steel journal-sleeve combinations; SCC of precipitation hardened and martensitic stainless steels; low temperature SCC of welded austenitic stainless steels by chloride, fluoride, and sulfur oxy-anions; and corrosion problems experienced by condensers.

  6. Metal corrosion coupon contamination, corrosion study design, and interpretation problems

    SciTech Connect

    Lytle, D.A.; Schock, M.R.; Tackett, S.

    1992-01-01

    As a result of the new Lead and Copper Rule, some water utilities in the United States have begun or will soon begin corrosion demonstration studies. Demonstration studies may include pipe rig/loop tests, metal coupon tests, and partial-system tests (full-scale). Evaluation of corrosion control treatment through testing may be accomplished by weight loss measurement, metal leaching, corrosion rate, or coupon surface inspection techniques. The purpose of the paper is to (1) briefly introduce 2 corrosion control studies being conducted at the EPA Research Facility, (2) discuss design and operational problems and considerations associated with each of the studies, and (3) present solutions to the problems. The experiences related to the paper may provide useful and time-saving insights into the design, operation, and interpretation of corrosion control studies to water utilities and suppliers.

  7. Accelerated atmospheric corrosion testing of electroplated gold mirror coatings

    NASA Astrophysics Data System (ADS)

    Chu, C.-T.; Alaan, D. R.; Taylor, D. P.

    2010-08-01

    Gold-coated mirrors are widely used in infrared optics for industrial, space, and military applications. These mirrors are often made of aluminum or beryllium substrates with polished nickel plating. Gold is deposited on the nickel layer by either electroplating or vacuum deposition processes. Atmospheric corrosion of gold-coated electrical connectors and contacts was a well-known problem in the electronic industry and studied extensively. However, there is limited literature data that correlates atmospheric corrosion to the optical properties of gold mirror coatings. In this paper, the atmospheric corrosion of different electroplated gold mirror coatings were investigated with an accelerated mixed flowing gas (MFG) test for up to 50 days. The MFG test utilizes a combination of low-level air pollutants, humidity, and temperatures to achieve a simulated indoor environment. Depending on the gold coating thickness, pore corrosion started to appear on samples after about 10 days of the MFG exposure. The corrosion behavior of the gold mirror coatings demonstrated the porous nature of the electroplated gold coatings as well as the variation of porosity to the coating thickness. The changes of optical properties of the gold mirrors were correlated to the morphology of corrosion features on the mirror surface.

  8. Accelerated Test Method for Corrosion Protective Coatings Project

    NASA Technical Reports Server (NTRS)

    Falker, John; Zeitlin, Nancy; Calle, Luz

    2015-01-01

    This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as accurately and reliably as current long-term atmospheric exposure tests. This new accelerated test method will shorten the time needed to evaluate the corrosion protection performance of coatings for NASA's critical ground support structures. Lifetime prediction for spaceport structure coatings has a 5-year qualification cycle using atmospheric exposure. Current accelerated corrosion tests often provide false positives and negatives for coating performance, do not correlate to atmospheric corrosion exposure results, and do not correlate with atmospheric exposure timescales for lifetime prediction.

  9. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerone C.; Kolody, Mark R.

    2011-01-01

    Evaluation of metal-based structures has long relied on atmospheric exposure test sites to determine corrosion resistance in marine environments. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions of the corrosive environment. Their success for correlation to atmospheric exposure is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated laboratory testing, which often focuses on the electrochemical reactions that occur during corrosion conditions, has yet to be universally accepted as a useful tool in predicting the long term service life of a metal despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard and their use is imperative, a method that correlates timescales from atmospheric exposure to accelerated testing would be very valuable. This work uses surface chemistry to interpret the chemical changes occurring on low carbon steel during atmospheric and accelerated corrosion conditions with the objective of finding a correlation between its accelerated and long-term corrosion performance. The current results of correlating data from marine atmospheric exposure conditions at the Kennedy Space Center beachside corrosion test site, alternating seawater spray, and immersion in typical electrochemical laboratory conditions, will be presented. Key words: atmospheric exposure, accelerated corrosion testing, alternating seawater spray, marine, correlation, seawater, carbon steel, long-term corrosion performance prediction, X-ray photoelectron spectroscopy.

  10. Disturbed flow and flow accelerated corrosion in oil and gas production

    SciTech Connect

    Efird, K.D.

    1998-12-31

    The effect of fluid flow on corrosion of steel in oil and gas environments involves a complex interaction of physical and chemical parameters. The basic requirement for any corrosion to occur is the existence of liquid water contacting the pipe wall, which is primarily controlled by the flow regime. The effect of flow on corrosion, or flow accelerated corrosion, is defined by the mass transfer and wall shear stress parameters existing in the water phase that contacts the pipe wall. While existing fluid flow equations for mass transfer and wall shear stress relate to equilibrium conditions, disturbed flow introduces non-equilibrium, steady state conditions not addressed by these equations, and corrosion testing in equilibrium conditions cannot be effectively related to corrosion in disturbed flow. The problem in relating flow effects to corrosion is that steel corrosion failures in oil and gas environments are normally associated with disturbed flow conditions as a result of weld beads, preexisting pits, bends, flanges, valves, tubing connections, etc. Steady state mass transfer and wall shear stress relationships to steel corrosion and corrosion testing are required for their application to corrosion of steel under disturbed flow conditions. A procedure is described to relate the results of a corrosion test directly to corrosion in an operation system where disturbed flow conditions are expected, or must be considered.

  11. On the Problem of Stress Corrosion

    NASA Technical Reports Server (NTRS)

    Graf, L.

    1946-01-01

    The object of the present work is first to investigate accurately the processes during stress corrosion, in particular, for light metal alloys and, as the first part of the investigation, to determine its laws; and secondly to explain its causes for various alloys and thereby find means for its partial or complete elimination and thus make possible the production of light metal alloys free from any stress corrosion. In the present paper some of the results of the investigation are given and the fundamental problems of stress corrosion discussed.

  12. Development and application of an information-analytic system on the problem of flow accelerated corrosion of pipeline elements in the secondary coolant circuit of VVER-440-based power units at the Novovoronezh nuclear power plant

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Povarov, V. P.; Shipkov, A. A.; Gromov, A. F.; Kiselev, A. N.; Shepelev, S. V.; Galanin, A. V.

    2015-02-01

    Specific features relating to development of the information-analytical system on the problem of flow-accelerated corrosion of pipeline elements in the secondary coolant circuit of the VVER-440-based power units at the Novovoronezh nuclear power plant are considered. The results from a statistical analysis of data on the quantity, location, and operating conditions of the elements and preinserted segments of pipelines used in the condensate-feedwater and wet steam paths are presented. The principles of preparing and using the information-analytical system for determining the lifetime to reaching inadmissible wall thinning in elements of pipelines used in the secondary coolant circuit of the VVER-440-based power units at the Novovoronezh NPP are considered.

  13. Irradiation-Accelerated Corrosion of Reactor Core Materials. Final Report

    SciTech Connect

    Jiao, Zhujie; Was, Gary; Bartels, David

    2015-04-02

    This project aims to understand how radiation accelerates corrosion of reactor core materials. The combination of high temperature, chemically aggressive coolants, a high radiation flux and mechanical stress poses a major challenge for the life extension of current light water reactors, as well as the success of most all GenIV concepts. Of these four drivers, the combination of radiation and corrosion places the most severe demands on materials, for which an understanding of the fundamental science is simply absent. Only a few experiments have been conducted to understand how corrosion occurs under irradiation, yet the limited data indicates that the effect is large; irradiation causes order of magnitude increases in corrosion rates. Without a firm understanding of the mechanisms by which radiation and corrosion interact in film formation, growth, breakdown and repair, the extension of the current LWR fleet beyond 60 years and the success of advanced nuclear energy systems are questionable. The proposed work will address the process of irradiation-accelerated corrosion that is important to all current and advanced reactor designs, but remains very poorly understood. An improved understanding of the role of irradiation in the corrosion process will provide the community with the tools to develop predictive models for in-reactor corrosion, and to address specific, important forms of corrosion such as irradiation assisted stress corrosion cracking.

  14. Predicting the impact of chromium on flow-accelerated corrosion

    SciTech Connect

    Chexal, B.; Goyette, L.F.; Horowitz, J.S.; Ruscak, M.

    1996-12-01

    Flow-Accelerated Corrosion (FAC) continues to cause problems in nuclear and fossil power plants. Many experiments have been performed to understand the mechanism of FAC. For approximately twenty years, it has ben widely recognized that the presence of small amounts of chromium will reduce the rate of FAC. This effect was quantified in the eighties by research performed in France, Germany and the Netherlands. The results of this research has been incorporated into the computer-based tools used by utility engineers to deal with this issue. For some time, plant data from Diablo Canyon has suggested that the existing correlations relating the concentration of chromium to the rate of FAC are conservative. Laboratory examinations have supported this observation. It appears that the existing correlations fail to capture a change in mechanism from a FAC process with linear kinetics to a general corrosion process with parabolic kinetics. This change in mechanism occurs at a chromium level of approximately 0.1%, within the allowable alloy range of typical carbon steel (ASTM/ASME A106 Grade B) used in power piping in most domestic plants. It has been difficult to obtain plant data that has sufficient chromium to develop a new correlation. Data from Diablo Canyon and the Dukovany Power Plant in the Czech Republic will be used to develop a new chromium correlation for predicting FAC rate.

  15. Accelerated corrosion test for aluminum-zinc alloy coatings

    SciTech Connect

    Simpson, T.C. . Homer Research Labs.)

    1993-07-01

    An electrochemically monitored etching method has been developed to enable accelerated service life testing of aluminum/zinc alloy coatings with a dendritic microstructure. The method involved pre-exposure of materials to the etching solution to remove the most active phases from the coatings. This process simulated the early phases of atmospheric corrosion. The method significantly shortened the time required for an atmospheric exposure test. Historical performance data and data collected using the accelerated test method agreed.

  16. Corrosion Embrittlement of Duralumin II Accelerated Corrosion Tests and the Behavior of High-Strength Aluminum Alloys of Different Compositions

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1928-01-01

    The permanence, with respect to corrosion, of light aluminum alloy sheets of the duralumin type, that is, heat-treatable alloys containing Cu, Mg, Mn, and Si is discussed. Alloys of this type are subject to surface corrosion and corrosion of the interior by intercrystalline paths. Results are given of accelerated corrosion tests, tensile tests, the effect on corrosion of various alloying elements and heat treatments, electrical resistance measurements, and X-ray examinations.

  17. Continuous acoustic emission monitoring of reinforced concrete under accelerated corrosion

    NASA Astrophysics Data System (ADS)

    Di Benedetti, M.; Loreto, G.; Nanni, A.; Matta, F.; Gonzalez-Nunez, M. A.

    2011-04-01

    The development of techniques capable of evaluating deterioration of reinforced concrete (RC) structures is instrumental to the advancement of techniques for the structural health monitoring (SHM) and service life estimate for constructed facilities. One of the main causes leading to degradation of RC is the corrosion of the steel reinforcement. This process can be modeled phenomenologically, while laboratory tests aimed at studying durability responses are typically accelerated in order to provide useful results within a realistic period of time. To assess the condition of damage in RC, a number of nondestructive methods have been recently studied. Acoustic emission (AE) is emerging as a nondestructive tool to detect the onset and progression of deterioration mechanisms. In this paper, the development of accelerated corrosion and continuous AE monitoring test set-up for RC specimens are presented. Relevant information are provided with regard to the characteristics of the corrosion circuit, continuous measurement and acquisition of corrosion potential, selection of AE sensors and AE parameter setting. The effectiveness of the setup in detecting and characterizing the initiation and progression of the corrosion phenomenon is discussed on the basis of preliminary results from small-scale, pre-cracked RC specimens, which are representative of areas near the clear cover in typical RC bridge members.

  18. Apollo experience report: The problem of stress-corrosion cracking

    NASA Technical Reports Server (NTRS)

    Johnson, R. E.

    1973-01-01

    Stress-corrosion cracking has been the most common cause of structural-material failures in the Apollo Program. The frequency of stress-corrosion cracking has been high and the magnitude of the problem, in terms of hardware lost and time and money expended, has been significant. In this report, the significant Apollo Program experiences with stress-corrosion cracking are discussed. The causes of stress-corrosion cracking and the corrective actions are discussed, in terminology familiar to design engineers and management personnel, to show how stress-corrosion cracking can be prevented.

  19. Reproduction of natural corrosion by accelerated laboratory testing methods

    SciTech Connect

    Luo, J.S.; Wronkiewicz, D.J.; Mazer, J.J.; Bates, J.K.

    1996-05-01

    Various laboratory corrosion tests have been developed to study the behavior of glass waste forms under conditions similar to those expected in an engineered repository. The data generated by laboratory experiments are useful for understanding corrosion mechanisms and for developing chemical models to predict the long-term behavior of glass. However, it is challenging to demonstrate that these test methods produce results that can be directly related to projecting the behavior of glass waste forms over time periods of thousands of years. One method to build confidence in the applicability of the test methods is to study the natural processes that have been taking place over very long periods in environments similar to those of the repository. In this paper, we discuss whether accelerated testing methods alter the fundamental mechanisms of glass corrosion by comparing the alteration patterns that occur in naturally altered glasses with those that occur in accelerated laboratory environments. This comparison is done by (1) describing the alteration of glasses reacted in nature over long periods of time and in accelerated laboratory environments and (2) establishing the reaction kinetics of naturally altered glass and laboratory reacted glass waste forms.

  20. METAL CORROSION COUPON CONTAMINATION, CORROSION STUDY DESIGN, AND INTERPRETATION PROBLEMS

    EPA Science Inventory

    As a result of the new Lead and Copper Rule, some water utilities in the United States have begun or will soon begin corrosion demonstration studies. emonstration studies may include pipe rig/loop tests, metal coupon tests, and partial-system tests (fullscale). valuation of corro...

  1. Corrosion problems with aqueous coolants, final report

    SciTech Connect

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  2. Timescale Correlation between Marine Atmospheric Exposure and Accelerated Corrosion Testing - Part 2

    NASA Technical Reports Server (NTRS)

    Montgomery, Eliza L.; Calle, Luz Marina; Curran, Jerome C.; Kolody, Mark R.

    2012-01-01

    Evaluation of metals to predict service life of metal-based structures in corrosive environments has long relied on atmospheric exposure test sites. Traditional accelerated corrosion testing relies on mimicking the exposure conditions, often incorporating salt spray and ultraviolet (UV) radiation, and exposing the metal to continuous or cyclic conditions similar to those of the corrosive environment. Their reliability to correlate to atmospheric exposure test results is often a concern when determining the timescale to which the accelerated tests can be related. Accelerated corrosion testing has yet to be universally accepted as a useful tool in predicting the long-term service life of a metal, despite its ability to rapidly induce corrosion. Although visual and mass loss methods of evaluating corrosion are the standard, and their use is crucial, a method that correlates timescales from accelerated testing to atmospheric exposure would be very valuable. This paper presents work that began with the characterization of the atmospheric environment at the Kennedy Space Center (KSC) Beachside Corrosion Test Site. The chemical changes that occur on low carbon steel, during atmospheric and accelerated corrosion conditions, were investigated using surface chemistry analytical methods. The corrosion rates and behaviors of panels subjected to long-term and accelerated corrosion conditions, involving neutral salt fog and alternating seawater spray, were compared to identify possible timescale correlations between accelerated and long-term corrosion performance. The results, as well as preliminary findings on the correlation investigation, are presented.

  3. Accelerated corrosion of stainless steel in thiocyanate-containing solutions

    SciTech Connect

    Pistorius, P Chris; Li, Wen

    2012-09-19

    It is known that reduced sulfur compounds (such as thiocyanate and thiosulfate) can accelerate active corrosion of austenitic stainless steel in acid solutions, but before we started this project the mechanism of acceleration was largely unclear. This work combined electrochemical measurements and analysis using scanning electron microscopy (SEM) and X-ray photo-electron spectroscopy (XPS), which provided a comprehensive understanding of the catalytic effect of reduced sulfur species on the active corrosion of stainless steel. Both the behavior of the pure elements and the steel were studied and the work focused on the interaction between the pure elements of the steel, which is the least understood area. Upon completion of this work, several aspects are now much clearer. The main results from this work can be summarized as follows: The presence of low concentrations (around 0.1 mM) of thiocyanate or tetrathionate in dilute sulfuric acid greatly accelerates the anodic dissolution of chromium and nickel, but has an even stronger effect on stainless steels (iron-chromium-nickel alloys). Electrochemical measurements and surface analyses are in agreement with the suggestion that accelerated dissolution really results from suppressed passivation. Even well below the passivation potential, the electrochemical signature of passivation is evident in the electrode impedance; the electrode impedance shows clearly that this pre-passivation is suppressed in the presence of thiocyanate. For the stainless steels, remarkable changes in the morphology of the corroded metal surface and in the surface concentration of chromium support the suggestion that pre-passivation of stainless steels is suppressed because dissolution of chromium is accelerated. Surface analysis confirmed that adsorbed sulfur / sulfide forms on the metal surfaces upon exposure to solutions containing thiocyanate or thiosulfate. For pure nickel, and steels containing nickel (and residual copper), bulk sulfide

  4. Accelerated erosion: Process, problems, and prognosis

    NASA Astrophysics Data System (ADS)

    Toy, Terrence J.

    1982-10-01

    Soil erosion may well be the world's most serious environmental problem. A variety of human activities accelerates the rate of this geomorphie process by altering the natural characteristics of a site. The problems arising from accelerated erosion and subsequent deposition provide numerous research opportunities to both physical and social scientists whose cooperation will be necessary in our search for solutions. Factors of demography, economics, geography, and historical inertia to change suggest that man-induced erosion is likely to continue into the future unless this trend is abated by timely and forceful action.

  5. Assessing corrosion problems in photovoltaic cells via electrochemical stress testing

    NASA Technical Reports Server (NTRS)

    Shalaby, H.

    1985-01-01

    A series of accelerated electrochemical experiments to study the degradation properties of polyvinylbutyral-encapsulated silicon solar cells has been carried out. The cells' electrical performance with silk screen-silver and nickel-solder contacts was evaluated. The degradation mechanism was shown to be electrochemical corrosion of the cell contacts; metallization elements migrate into the encapsulating material, which acts as an ionic conducting medium. The corrosion products form a conductive path which results in a gradual loss of the insulation characteristics of the encapsulant. The precipitation of corrosion products in the encapsulant also contributes to its discoloration which in turn leads to a reduction in its transparency and the consequent optical loss. Delamination of the encapsulating layers could be attributed to electrochemical gas evolution reactions. The usefulness of the testing technique in qualitatively establishing a reliability difference between metallizations and antireflection coating types is demonstrated.

  6. Control problems in very large accelerators

    SciTech Connect

    Crowley-Milling, M.C.

    1985-04-01

    There is no fundamental difference of kind in the control requirements between a small and a large accelerator since they are built of the same types of components, which individually have the same types of control inputs and outputs. The main difference is one of scale; the large machine has many more components of each type, and the distances involved are much greater. It is the purpose of this paper to look at the special control problems of large accelerators, which the author shall arbitrarily define as those with a length or circumference in excess of 10 km, and point out where special developments, or the adoption of developments from outside the accelerator control field, can be of assistance in minimizing the cost of the control system.

  7. Control problems in very large accelerators

    SciTech Connect

    Crowley-Milling, M.C.

    1985-06-01

    There is no fundamental difference of kind in the control requirements between a small and a large accelerator since they are built of the same types of components, which individually have similar control inputs and outputs. The main difference is one of scale; the large machine has many more components of each type, and the distances involved are much greater. Both of these factors must be taken into account in determining the optimum way of carrying out the control functions. Small machines should use standard equipment and software for control as much as possible, as special developments for small quantities cannot normally be justified if all costs are taken into account. On the other hand, the very great number of devices needed for a large machine means that, if special developments can result in simplification, they may make possible an appreciable reduction in the control equipment costs. It is the purpose of this report to look at the special control problems of large accelerators, which the author shall arbitarily define as those with a length of circumference in excess of 10 km, and point out where special developments, or the adoption of developments from outside the accelerator control field, can be of assistance in minimizing the cost of the control system. Most of the first part of this report was presented as a paper to the 1985 Particle Accelerator Conference. It has now been extended to include a discussion on the special case of the controls for the SSC.

  8. CFD Application to Flow-Accelerated Corrosion in Feeder Bends

    SciTech Connect

    Pietralik, John M.; Smith, Bruce A.W.

    2006-07-01

    Feeder piping in CANDU{sup R} plants experiences a thinning degradation mechanism called Flow-Accelerated Corrosion (FAC). The piping is made of carbon steel and has high water flow speeds. Although the water chemistry is highly alkaline with room-temperature pH in a range of 10.0-10.5, the piping has FAC rates exceeding 0.1 mm/year in some locations, e.g., in bends. One of the most important parameters affecting the FAC rate is the mass transfer coefficient for convective mass transport of ferrous ions. The ions are created at the pipe wall as a result of corrosion, diffuse through the oxide layer, and are transported from the oxide-layer/water interface to the bulk water by mass transport. Consequently, the local flow characteristics contribute to the highly turbulent convective mass transfer. Plant data and laboratory experiments indicate that the mass transfer step dominates FAC under feeder conditions. In this study, the flow and mass transfer in a feeder bend under operating conditions were simulated using the Fluent{sup TM} computer code. Because the flow speed is very high, with the Reynolds numbers in a range of several millions, and because the geometry is complex, experiments in a 1:1 scale were conducted with the main objective to validate flow simulations. The experiments measured pressure at several key locations and visualized the flow. The flow and mass transfer models were validated using available friction-factor and mass transfer correlations and literature experiments on mass transfer in a bend. The validation showed that the turbulence model that best predicts the experiments is the realizable k-{epsilon} model. Other two-equation turbulence models, as well as one-equation models and Reynolds stress models were tried. The near-wall treatment used the non-equilibrium wall functions. The wall functions were modified for surface roughness when necessary. A comparison of the local mass transfer coefficient with measured FAC rate in plant specimens

  9. A facility for studying irradiation accelerated corrosion in high temperature water

    NASA Astrophysics Data System (ADS)

    Raiman, Stephen S.; Flick, Alexander; Toader, Ovidiu; Wang, Peng; Samad, Nassim A.; Jiao, Zhijie; Was, Gary S.

    2014-08-01

    A facility for the study of irradiation accelerated corrosion in high temperature water using in situ proton irradiation has been developed and validated. A specially designed beamline and flowing-water corrosion cell added to the 1.7 MV tandem accelerator at the Michigan Ion Beam Laboratory provide the capability to study the simultaneous effects of displacement damage and radiolysis on corrosion. A thin sample serves as both a “window” into the corrosion cell through which the proton beam passes completely, and the sample for assessing irradiation accelerated corrosion. The facility was tested by irradiating stainless steel samples at beam current densities between 0.5 and 10 μA/cm2 in 130 °C and 320 °C deaerated water, and 320 °C water with 3 wppm H2. Increases in the conductivity and dissolved oxygen content of the water varied with the proton beam current, suggesting that proton irradiation was accelerating the corrosion of the sample. Conductivity increases were greatest at 320 °C, while DO increases were highest at 130 °C. The addition of 3 wppm H2 suppressed DO below detectable levels. The facility will enable future studies into the effect of irradiation on corrosion in high temperature water with in situ proton irradiation.

  10. Flow-accelerated corrosion in power plants. Revision 1

    SciTech Connect

    Chexal, B.; Horowitz, J.; Dooley, B.

    1998-07-01

    Flow-Accelerated Corrosion (FAC) is a phenomenon that results in metal loss from piping, vessels, and equipment made of carbon steel. FAC occurs only under certain conditions of flow, chemistry, geometry, and material. Unfortunately, those conditions are common in much of the high-energy piping in nuclear and fossil-fueled power plants. Undetected, FAC will cause leaks and ruptures. Consequently, FAC has become a major issue, particularly for nuclear plants. Although major failures are rare, the consequences can be severe. In 1986, four men in the area of an FAC-induced pipe rupture were killed. Fossil plants too, are subject to FAC. In 1995, a failure at a fossil-fired plant caused two fatalities. In addition to concerns about personnel safety, FAC failures can pose challenges to plant safety. Regulatory agencies have therefore required nuclear utilities to institute formal programs to address FAC. Finally, a major FAC failure (like the one that happened in 1997 at a US nuclear power plant) can force a plant to shutdown and purchase replacement power at a price approaching a million dollars per day depending upon the MWe rating of the plant. A great deal of time and money has been spent to develop the technology to predict, detect, and mitigate FAC in order to prevent catastrophic failures. Over time, substantial progress has been made towards understanding and preventing FAC. The results of these efforts include dozens of papers, reports, calculations, and manuals, as well as computer programs and other tools. This book is written to provide a detailed treatment of the entire subject in a single document. Any complex issue requires balancing know-how, the risk of decision making, and a pragmatic engineering solution. This book addresses these by carrying out the necessary R and D and engineering along with plant knowledge to cover all quadrants of Chexal`s four quadrant known-unknown diagram, as seen in Figure i.

  11. Mechanism of accelerated corrosion in Zircaloy-4 laser and electron-beam welds

    SciTech Connect

    McDonald, S.G.; Sabol, G.P.

    1982-01-01

    The corrosion resistance of a series of Zircaloy-4 laser, electron-beam (EB), and tungsten inert gas (TIG) welds was evaluated in high-temperature water and steam. Corrosion exposures carried out in 633 K water revealed that all welds had excellent corrosion resistance at this temperature. However, corrosion exposures carried out in 673 K steam indicated that the laser and EB welds were susceptible to accelerated corrosion, whereas the TIG welds were not. It is believed that alloy depletion and the resultant loss of high-temperature corrosion resistance can be eliminated or minimized by performing welding operations at a power density such that the metal surface is heated above the melting point, but below the boiling point. 23 refs.

  12. Chexal-Horowitz flow-accelerated corrosion model -- Parameters and influences

    SciTech Connect

    Chexal, V.K.; Horowitz, J.S.

    1995-12-01

    Flow-accelerated corrosion (FAC) continues to cause problems in nuclear and fossil power plants. Thinning caused by FAC has lead to many leaks and complete ruptures. These failures have required costly repairs and occasionally have caused lengthy shutdowns. To deal with FAC, utilities have instituted costly inspection and piping replacement programs. Typically, a nuclear unit will inspect about 100 large bore piping components plus additional small bore components during every refueling outage. To cope with FAC, there has been a great deal of research and development performed to obtain a greater understanding of the phenomenon. Currently, there is general agreement on the mechanism of FAC. This understanding has lead to the development of computer based tools to assist utility engineers in dealing with this issue. In the United States, the most commonly used computer program to predict and control is CHECWORKS{trademark}. This paper presents a description of the mechanism of FAC, and introduces the predictive algorithms used in CHECWORKS{trademark}. The parametric effects of water chemistry, materials, flow and geometry as predicted by CHECWORKS{trademark} will then be discussed. These trends will be described and explained by reference to the corrosion mechanism. The remedial actions possible to reduce the rate of damage caused by FAC will also be discussed.

  13. Corrosion behavior of modified nano carbon black/epoxy coating in accelerated conditions

    NASA Astrophysics Data System (ADS)

    Ghasemi-Kahrizsangi, Ahmad; Shariatpanahi, Homeira; Neshati, Jaber; Akbarinezhad, Esmaeil

    2015-03-01

    The electrochemical behavior and anticorrosion properties of modified carbon black (CB) nanoparticles in epoxy coatings were investigated in accelerated conditions. Nanoparticles of CB were modified by sodium dodecyl sulfate (SDS) as surfactant. Dispersion of nanoparticles into epoxy was confirmed by Transmission Electron Microscopy (TEM). The accelerated condition was prepared at 65 °C. CB nanoparticles improved corrosion resistance of the epoxy coating. The optimum concentration of CB in the epoxy coating was 0.75 wt%. Results showed that the CB hinder the corrosion due to its barrier properties. CB can decrease the diffusion coefficient of water in the coating with filling the micropores.

  14. Four steps solve crude-tower overhead corrosion problems

    SciTech Connect

    Lieberman, N.P. )

    1993-07-05

    Hydrochloric acid attack is one of the oldest and best-understood refinery process problems. This would lead one to think that preventing localized hydrochloric acid attack would also be well-understood. Experience, however, indicates that this is far from true. The problem originates with the presence of salt water in crude oils. Most of the salt content of the brine dispersed in crudes is in the form of sodium chloride (NaCl). About 10% of the salt, however, is present as magnesium chloride (MgCl[sub 2]) and calcium chloride (CaCl[sub 2]). In the presence of water and heat, these chloride salts hydrolyze to form HCI. The two-stage overhead system using the hot and cold drum is a design that, despite its widespread use, does not fulfill its objective of stopping crude-tower overhead corrosion. The following program is, in the opinion of the author, the only way to halt overhead corrosion in a crude tower: effective desalting that removes more than 60% of the MgCl[sub 2]; caustic injection down-stream of the desalter to control chlorides in the reflux-drum water draw-off boot; forced water condensation in the crude-tower overhead vapors; and sufficient addition of neutralizing amine to control water boot at a pH of about 6. Finally, there can never be a truly effective replacement for proper desalting. Process Improvement Engineering's experience has repeatedly proven that desalting is the most cost-effective method of controlling hydroscopic hydrochloric acid corrosion. When downstream resid-hydrotreating processes preclude the use of neutralizing caustic, the importance of the desalter is magnified even further.

  15. SYMMETRY, HAMILTONIAN PROBLEMS AND WAVELETS IN ACCELERATOR PHYSICS

    SciTech Connect

    FEDOROVA,A.; ZEITLIN,M.; PARSA,Z.

    2000-03-31

    In this paper the authors consider applications of methods from wavelet analysis to nonlinear dynamical problems related to accelerator physics. In this approach they take into account underlying algebraical, geometrical and topological structures of corresponding problems.

  16. Solving radiation problems at particle accelerators

    SciTech Connect

    Nikolai V. Mokhov

    2001-12-11

    At high-intensity high-energy particle accelerators, consequences of a beam-induced radiation impact on machine and detector components, people, environment and complex performance can range from negligible to severe. The specifics, general approach and tools used at such machines for radiation analysis are described. In particular, the world leader Fermilab accelerator complex is considered, with its fixed target and collider experiments, as well as new challenging projects such as LHC, VLHC, muon collider and neutrino factory. The emphasis is on mitigation of deleterious beam-induced radiation effects and on the key role of effective computer simulations.

  17. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

    Presents some materials for use in demonstration and experimentation of corrosion processes, including corrosion stimulation and inhibition. Indicates that basic concepts of electrochemistry, crystal structure, and kinetics can be extended to practical chemistry through corrosion explanation. (CC)

  18. STOCHASTIC PARTICLE ACCELERATION AND THE PROBLEM OF BACKGROUND PLASMA OVERHEATING

    SciTech Connect

    Chernyshov, D. O.; Dogiel, V. A.; Ko, C. M.

    2012-11-10

    The origin of hard X-ray (HXR) excess emission from clusters of galaxies is still an enigma, whose nature is debated. One of the possible mechanisms to produce this emission is the bremsstrahlung model. However, previous analytical and numerical calculations showed that in this case the intracluster plasma had to be overheated very fast because suprathermal electrons emitting the HXR excess lose their energy mainly by Coulomb losses, i.e., they heat the background plasma. It was concluded also from these investigations that it is problematic to produce emitting electrons from a background plasma by stochastic (Fermi) acceleration because the energy supplied by external sources in the form of Fermi acceleration is quickly absorbed by the background plasma. In other words, the Fermi acceleration is ineffective for particle acceleration. We revisited this problem and found that at some parameter of acceleration the rate of plasma heating is rather low and the acceleration tails of nonthermal particles can be generated and exist for a long time while the plasma temperature is almost constant. We showed also that for some regime of acceleration the plasma cools down instead of being heated up, even though external sources (in the form of external acceleration) supply energy to the system. The reason is that the acceleration withdraws effectively high-energy particles from the thermal pool (analog of Maxwell demon).

  19. New ways of investigating the canonical coin toss acceleration problem

    NASA Astrophysics Data System (ADS)

    Wittmann, Michael C.; Hawkins, Jeffrey M.

    2013-01-01

    Asking students about the acceleration of a tossed object is a well-studied problem in physics education research. Students frequently respond using reasoning that describes the velocity of the object, in particular that acceleration is zero at the top. We created new versions of the canonical multiple-choice Force and Motion Conceptual Evaluation coin-toss questions to investigate what other reasoning students might use. Some students were asked "is the acceleration zero at the top?" Other students were told "the acceleration is not zero" and asked to explain. A third group answered the original multiple-choice version of the question. Our results suggest that some students give answers that they can explain are incorrect. We also find that some students' responses about the acceleration at the turnaround point are affected by question format.

  20. The effects of trace impurities in coal-derived liquid fuels on deposition and accelerated high temperature corrosion of cast superalloys

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Deadmore, D. J.; Santoro, G. J.; Kohl, F. J.

    1981-01-01

    The effects of trace metal impurities in coal-derived liquids on deposition, high temperature corrosion and fouling were examined. Alloys were burner rig tested from 800 to 1100 C and corrosion was evaluated as a function of potential impurities. Actual and doped fuel test were used to define an empirical life prediction equation. An evaluation of inhibitors to reduce or eliminate accelerated corrosion was made. Barium and strontium were found to limit attack. Intermittent application of the inhibitors or silicon additions were found to be effective techniques for controlling deposition without losing the inhibitor benefits. A computer program was used to predict the dew points and compositions of deposits. These predictions were confirmed in deposition test. The potential for such deposits to plug cooling holes of turbine airfoils was evaluated. Tests indicated that, while a potential problem exists, it strongly depended on minor impurity variations.

  1. Corrosion Embrittlement of Duralumin I Practical Aspects of the Problem

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1928-01-01

    Since aircraft design is tending toward all-metal construction, the strong heat-treatable light aluminum alloy, duralumin (a generic name for a class of heat-treatable alloys containing Cu, Mg, Mn, and Si), is finding increasing application. Doubt has been expressed concerning the reliability and permanence of these materials. Information is given on the effect of corrosion on the tensile properties of 14-gauge sheet duralumin, heat treated by quenching in hot water after being heated for 15 minutes in a fused nitrate bath at 500 to 510 C. Intercrystalline corrosion and practical aspects of intercrystalline embrittlement are discussed with respect to duralumin.

  2. UNSOLVED PROBLEMS WITH CORROSION AND DISTRIBUTION SYSTEM INORGANICS

    EPA Science Inventory

    This presentation provides an overview of new research results and remaining research needs with respect to both corrosion control issues (lead, copper, iron) and to issues of inorganic contaminants that can form or accumulate in distribution system water, pipe scales and distrib...

  3. Corrosion characterization of durable silver coatings by electrochemical impedance spectroscopy and accelerated environmental testing.

    PubMed

    Chu, Chung-Tse; Fuqua, Peter D; Barrie, James D

    2006-03-01

    Highly reflective front-surface silver mirrors are needed for many optical applications. While various protective dielectric coating schemes have been developed, the long-term durability of Ag mirrors is still of great concern in the optics community for a variety of applications under harsh environments. The corrosion protection behavior of a SiNx-coated silver-mirror coating scheme was tested with electrochemical impedance spectroscopy (EIS) and accelerated environmental testing, including humidity and salt fog tests. The EIS data obtained were fitted with different equivalent circuit models. The results suggested that the 100A thick SiNx coating produced by rf magnetron sputtering was porous and acted as a leaky capacitor on the Ag film, whereas the addition of a NiCrNx interlayer as thin as 3A between SiNx and Ag films resulted in a much denser SiNx coating with a low-frequency impedance value of 2 orders of magnitude higher than that without the interlayer. Humidity and salt fog testing of different silver coatings showed similar results. The 100A SiNx/3A-NiCrNx/Ag coating exhibited excellent corrosion resistance against the corrosive environments used in this study. PMID:16539267

  4. Innovative Applications of Genetic Algorithms to Problems in Accelerator Physics

    SciTech Connect

    Hofler, Alicia; Terzic, Balsa; Kramer, Matthew; Zvezdin, Anton; Morozov, Vasiliy; Roblin, Yves; Lin, Fanglei; Jarvis, Colin

    2013-01-01

    The genetic algorithm (GA) is a relatively new technique that implements the principles nature uses in biological evolution in order to optimize a multidimensional nonlinear problem. The GA works especially well for problems with a large number of local extrema, where traditional methods (such as conjugate gradient, steepest descent, and others) fail or, at best, underperform. The field of accelerator physics, among others, abounds with problems which lend themselves to optimization via GAs. In this paper, we report on the successful application of GAs in several problems related to the existing CEBAF facility, the proposed MEIC at Jefferson Lab, and a radio frequency (RF) gun based injector. These encouraging results are a step forward in optimizing accelerator design and provide an impetus for application of GAs to other problems in the field. To that end, we discuss the details of the GAs used, including a newly devised enhancement, which leads to improved convergence to the optimum and make recommendations for future GA developments and accelerator applications.

  5. Clad piping - a novel approach for solving nuclear plant service water and erosion-corrosion problems

    SciTech Connect

    Chakravarti, B.

    1992-12-31

    This paper discusses the application of clad piping components to solve various nuclear plant corrosion problems, such as service water system corrosion and feedwater/condensate/steam erosion-corrosion. This approach uses a carbon steel piping component which has a metallurgically bonded alloy cladding on the ID. Different alloys are available as cladding, from stainless steels to Inconel 625, so that a specific alloy can be selected based on the service requirements. Clad piping components represent a novel approach, as they provide a mechanism to utilize resistant alloys to solve corrosion problems without affecting the plant design. Clad piping products are designed such that the carbon steel backing acts as the pressure boundary and the cladding the corrosion allowance. By selecting the proper carbon steel backing, the clad product can be engineered to allow {open_quotes}like-for-like{close_quotes} component replacement. The wall thickness, weight and stiffness of the piping would remain essentially the same. The thermal expansion coefficient of the bulk piping also remains the same. Thus, the piping design and layout is wholly unaffected, with no structural reanalysis being required. This paper discusses two applications where clad piping products are being applied for solving nuclear power plant corrosion problems. The first is in solving steam/condensate/feedwater erosion-corrosion. The second application is the utilization of Inconel 625 clad piping products for solving service water system corrosion. Clad piping products solve these problems while improving plant operation and performance by basically providing the benefits of the alloy without any of the accompanying disadvantages of redesign.

  6. Optimized planning of in-service inspections of local flow-accelerated corrosion of pipeline elements used in the secondary coolant circuit of the VVER-440-based units at the Novovoronezh NPP

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Povarov, V. P.; Shipkov, A. A.; Gromov, A. F.; Budanov, V. A.; Golubeva, T. N.

    2015-03-01

    Matters concerned with making efficient use of the information-analytical system on the flow-accelerated corrosion problem in setting up in-service examination of the metal of pipeline elements operating in the secondary coolant circuit of the VVER-440-based power units at the Novovoronezh NPP are considered. The principles used to select samples of pipeline elements in planning ultrasonic thickness measurements for timely revealing metal thinning due to flow-accelerated corrosion along with reducing the total amount of measurements in the condensate-feedwater path are discussed.

  7. Wavelet approach to accelerator problems. 1: Polynomial dynamics

    SciTech Connect

    Fedorova, A.; Zeitlin, M.; Parsa, Z.

    1997-05-01

    This is the first part of a series of talks in which the authors present applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. In the general case they have the solution as a multiresolution expansion in the base of compactly supported wavelet basis. The solution is parameterized by solutions of two reduced algebraical problems, one is nonlinear and the second is some linear problem, which is obtained from one of the next wavelet constructions: Fast Wavelet Transform, Stationary Subdivision Schemes, the method of Connection Coefficients. In this paper the authors consider the problem of calculation of orbital motion in storage rings. The key point in the solution of this problem is the use of the methods of wavelet analysis, relatively novel set of mathematical methods, which gives one a possibility to work with well-localized bases in functional spaces and with the general type of operators (including pseudodifferential) in such bases.

  8. Half-range acceleration for one-dimensional transport problems

    SciTech Connect

    Zika, M.R.; Larsen, E.W.

    1998-12-31

    Researchers have devoted considerable effort to developing acceleration techniques for transport iterations in highly diffusive problems. The advantages and disadvantages of source iteration, rebalance, diffusion synthetic acceleration (DSA), transport synthetic acceleration (TSA), and projection acceleration methods are documented in the literature and will not be discussed here except to note that no single method has proven to be applicable to all situations. Here, the authors describe a new acceleration method that is based solely on transport sweeps, is algebraically linear (and is therefore amenable to a Fourier analysis), and yields a theoretical spectral radius bounded by one-third for all cases. This method does not introduce spatial differencing difficulties (as is the case for DSA) nor does its theoretical performance degrade as a function of mesh and material properties (as is the case for TSA). Practical simulations of the new method agree with the theoretical predictions, except for scattering ratios very close to unity. At this time, they believe that the discrepancy is due to the effect of boundary conditions. This is discussed further.

  9. Comparative study of the corrosion behavior of peripheral stents in an accelerated corrosion model: experimental in vitro study of 28 metallic vascular endoprostheses

    PubMed Central

    Paprottka, Karolin J.; Paprottka, Philipp M.; Reiser, Maximilian F.; Waggershauser, Tobias

    2015-01-01

    PURPOSE Clinical cases of stent-fractures show that corrosion behavior might play a role in these fractures. Implanted in vivo, especially in combination with other implanted foreign materials, these metallic products are exposed to special conditions, which can cause a process of corrosion. Here, we aimed to test the corrosion potential of stents made of different materials in an in vitro setting. METHODS A total of 28 peripheral stents of different materials (nitinol, cobalt-chromium-nickel, tantalum, V4A) and surface treatments (electropolish, mechanical polish, no polish) were tested in vitro. Corrosion was accelerated by applying a constant voltage of 3.5 V and amperage of 1.16 mA in 0.9% NaCl. RESULTS Nitinol stents showed the lowest susceptibility to corrosion and the longest period without damage. The Memotherm II® (BARD Angiomed®) was the only stent that showed neither macroscopic nor microscopic damages. The worst performing material was cobalt-chromium-nickel, which showed corrosion damages about ten times earlier compared to nitinol. Considering the reasons for termination of the test, nitinol stents primarily showed length deficits, while V4A and tantalum stents showed fractures. Cobalt-chromium-nickel stents had multiple fractures or a complete lysis in equal proportions. When placed in direct contact, nitinol stents showed best corrosion resistance, regardless of what material they were combined with. In terms of polishing treatments, electropolished stents performed the best, mechanical-polished stents and those without polishing treatment followed. CONCLUSION The analysis of corrosion behavior may be useful to select the right stent fulfilling the individual needs of the patient within a large number of different stents. PMID:26268301

  10. High Temperature Corrosion Problem of Boiler Components in presence of Sulfur and Alkali based Fuels

    NASA Astrophysics Data System (ADS)

    Ghosh, Debashis; Mitra, Swapan Kumar

    2011-04-01

    Material degradation and ageing is of particular concern for fossil fuel fired power plant components. New techniques/approaches have been explored in recent years for Residual Life assessment of aged components and material degradation due to different damage mechanism like creep, fatigue, corrosion and erosion etc. Apart from the creep, the high temperature corrosion problem in a fossil fuel fired boiler is a matter of great concern if the fuel contains sulfur, chlorine sodium, potassium and vanadium etc. This paper discusses the material degradation due to high temperature corrosion in different critical components of boiler like water wall, superheater and reheater tubes and also remedial measures to avoid the premature failure. This paper also high lights the Residual Life Assessment (RLA) methodology of the components based on high temperature fireside corrosion. of different critical components of boiler.

  11. Application of nonlinear Krylov acceleration to radiative transfer problems

    SciTech Connect

    Till, A. T.; Adams, M. L.; Morel, J. E.

    2013-07-01

    The iterative solution technique used for radiative transfer is normally nested, with outer thermal iterations and inner transport iterations. We implement a nonlinear Krylov acceleration (NKA) method in the PDT code for radiative transfer problems that breaks nesting, resulting in more thermal iterations but significantly fewer total inner transport iterations. Using the metric of total inner transport iterations, we investigate a crooked-pipe-like problem and a pseudo-shock-tube problem. Using only sweep preconditioning, we compare NKA against a typical inner / outer method employing GMRES / Newton and find NKA to be comparable or superior. Finally, we demonstrate the efficacy of applying diffusion-based preconditioning to grey problems in conjunction with NKA. (authors)

  12. Investigation of Accelerated Casing Corrosion in Two Wells at Waste Management Area A-AX

    SciTech Connect

    Brown, Christopher F.; Serne, R JEFFREY.; Schaef, Herbert T.; Williams, Bruce A.; Valenta, Michelle M.; LeGore, Virginia L.; Lindberg, Michael J.; Geiszler, Keith N.; Baum, Steven R.; Kutnyakov, Igor V.; Vickerman, Tanya S.; Clayton, Ray E.

    2005-08-29

    The sidewall core samples from well 299-E24-19, which were comprised of a mixture of bentonite and silt lens material, had an average porewater chloride concentration of 376 mg/L. The sidewall core samples collected from well 299-E25-46 had calculated porewater chloride concentrations ranging from 1,200 to more than 10,000 mg/L. Clearly, the sidewall core samples tested were capable of generating porewaters with sufficient chloride concentrations to cause corrosion of the stainless steel well casing. Furthermore, analysis of the sidewall core samples yielded a clear relationship between chloride concentration and well casing corrosion. The sidewall core samples containing the greatest amount of chloride, 3000 {micro}g/g of sediment, came from the well that experienced the longest length of casing failure (4.2 feet in well 299-E25-46). All of the sidewall core samples tested from both decommissioned wells contained more chloride than the Wyoming bentonite test material. However, since chloride was present as a trace constituent in all of the sidewall core samples (less than 0.4 weight percent), it is possible that it could have been introduced to the system as a ''contaminant'' contained in the bentonite backfill material. Therefore, it is likely that chloride leached from the bentonite material and/or chloride carried by/as a constituent of the liquid waste stream caused the advanced well casing corrosion found at wells 299-E24-19 and 299-E25-46 via crevice corrosion and stress corrosion cracking. The sample of Enviroplug{trademark} No.8 high swelling Wyoming bentonite was characterized for its potential to generate porewaters of sufficient chlorinity to lead to accelerated corrosion of type 304L stainless steel. Overall, the bentonite sample had considerably high water extractable concentrations of sodium, chloride, fluoride, sulfate, and alkalinity (measured as calcium carbonate). Interpretation of the laboratory data indicated that the Wyoming bentonite test

  13. Electron mediators accelerate the microbiologically influenced corrosion of 304 stainless steel by the Desulfovibrio vulgaris biofilm.

    PubMed

    Zhang, Peiyu; Xu, Dake; Li, Yingchao; Yang, Ke; Gu, Tingyue

    2015-02-01

    In the microbiologically influenced corrosion (MIC) caused by sulfate reducing bacteria (SRB), iron oxidation happens outside sessile cells while the utilization of the electrons released by the oxidation process for sulfate reduction occurs in the SRB cytoplasm. Thus, cross-cell wall electron transfer is needed. It can only be achieved by electrogenic biofilms. This work hypothesized that the electron transfer is a bottleneck in MIC by SRB. To prove this, MIC tests were carried out using 304 stainless steel coupons covered with the Desulfovibrio vulgaris (ATCC 7757) biofilm in the ATCC 1249 medium. It was found that both riboflavin and flavin adenine dinucleotide (FAD), two common electron mediators that enhance electron transfer, accelerated pitting corrosion and weight loss on the coupons when 10ppm (w/w) of either of them was added to the culture medium in 7-day anaerobic lab tests. This finding has important implications in MIC forensics and biofilm synergy in MIC that causes billions of dollars of damages to the US industry each year. PMID:25023048

  14. An accelerated carbonation procedure for studies of corrosion in reinforced concrete

    SciTech Connect

    Al-Kadhimi, T.K.H.; Banfill, P.F.G.; Millard, S.G.; Bungey, J.H.

    1995-10-01

    Carbonation of the concrete leading to reduced alkalinity around the steel is one of the main reasons for the corrosion of reinforced concrete. Studies of carbonation induced corrosion and of rehabilitation methods, such as electrochemical realkalization, require the convenient preparation of realistically large specimens of carbonated concrete in a sufficiently short time. This paper describes a rapid method of preparing carbonated concrete by exposing concrete, which has been dried to an internal relative humidity of 60%, to a pure atmosphere of carbon dioxide gas at 15 bar pressure (1,500 kPa). The pressure chamber used can accommodate specimens up to 150mm diameter or 100 x 100 mm section and such specimens can be fully carbonated in 2 weeks, much more quickly than by other methods. Carbonation increases the electrical resistivity and strength of the concrete and reduces the water absorption. Optical and electron microscopical investigations on the carbonated concrete confirm that the microstructure is no different from that produced in concrete by carbonation under natural exposure. The accelerated carbonation method can be used for development work on materials and repair methods and has been used by the authors in preparing carbonated concrete specimens for re-alkalization tests.

  15. Application of gamma-ray radiography and gravimetric measurements after accelerated corrosion tests of steel embedded in mortar

    SciTech Connect

    Duffó, Gustavo; Gaillard, Natalia; Mariscotti, Mario; Ruffolo, Marcelo

    2015-08-15

    The accelerated corrosion by the impressed current technique is widely used in studies of concrete durability since it has the advantage that tests can be carried out within reasonable periods of time. In the present work the relationship between the applied current density and the resulting damage on the reinforcing steel, by applying optical microscopy, scanning electron microscopy, gamma-ray radiography and gravimetric measurements, was studied by means of the implementation of accelerated corrosion tests on reinforced mortar. The results show that the efficiency of the applied current is between 1 and 77%, regardless of the applied current density, the water/cement ratio and the mortar cover depth of the specimens. The results show the applicability of the gamma-ray radiography technique to detect localized corrosion of steel rebars in laboratory specimens.

  16. Parallel Monte Carlo Synthetic Acceleration methods for discrete transport problems

    NASA Astrophysics Data System (ADS)

    Slattery, Stuart R.

    This work researches and develops Monte Carlo Synthetic Acceleration (MCSA) methods as a new class of solution techniques for discrete neutron transport and fluid flow problems. Monte Carlo Synthetic Acceleration methods use a traditional Monte Carlo process to approximate the solution to the discrete problem as a means of accelerating traditional fixed-point methods. To apply these methods to neutronics and fluid flow and determine the feasibility of these methods on modern hardware, three complementary research and development exercises are performed. First, solutions to the SPN discretization of the linear Boltzmann neutron transport equation are obtained using MCSA with a difficult criticality calculation for a light water reactor fuel assembly used as the driving problem. To enable MCSA as a solution technique a group of modern preconditioning strategies are researched. MCSA when compared to conventional Krylov methods demonstrated improved iterative performance over GMRES by converging in fewer iterations when using the same preconditioning. Second, solutions to the compressible Navier-Stokes equations were obtained by developing the Forward-Automated Newton-MCSA (FANM) method for nonlinear systems based on Newton's method. Three difficult fluid benchmark problems in both convective and driven flow regimes were used to drive the research and development of the method. For 8 out of 12 benchmark cases, it was found that FANM had better iterative performance than the Newton-Krylov method by converging the nonlinear residual in fewer linear solver iterations with the same preconditioning. Third, a new domain decomposed algorithm to parallelize MCSA aimed at leveraging leadership-class computing facilities was developed by utilizing parallel strategies from the radiation transport community. The new algorithm utilizes the Multiple-Set Overlapping-Domain strategy in an attempt to reduce parallel overhead and add a natural element of replication to the algorithm. It

  17. Influence of Local Flow Field on Flow Accelerated Corrosion Downstream from an Orifice

    NASA Astrophysics Data System (ADS)

    Utanohara, Yoichi; Nagaya, Yukinori; Nakamura, Akira; Murase, Michio

    Flow accelerated corrosion (FAC) rate downstream from an orifice was measured in a high-temperature water test loop to evaluate the effects of flow field on FAC. Orifice flow was also measured using laser Doppler velocimetry (LDV) and simulated by steady RANS simulation and large eddy simulation (LES). The LDV measurements indicated the flow structure did not depend on the flow velocity in the range of Re = 2.3×104 to 1.2×105. Flow fields predicted by RANS and LES agreed well with LDV data. Measured FAC rate was higher downstream than upstream from the orifice and the maximum appeared at 2D (D: pipe diameter) downstream. The shape of the profile of the root mean square (RMS) wall shear stress predicted by LES had relatively good agreement with the shape of the profile of FAC rate. This result indicates that the effects of flow field on FAC can be evaluated using the calculated wall shear stress.

  18. Wavelet approach to accelerator problems. 2: Metaplectic wavelets

    SciTech Connect

    Fedorova, A.; Zeitlin, M.; Parsa, Z.

    1997-05-01

    This is the second part of a series of talks in which the authors present applications of wavelet analysis to polynomial approximations for a number of accelerator physics problems. According to the orbit method and by using construction from the geometric quantization theory they construct the symplectic and Poisson structures associated with generalized wavelets by using metaplectic structure and corresponding polarization. The key point is a consideration of semidirect product of Heisenberg group and metaplectic group as subgroup of automorphisms group of dual to symplectic space, which consists of elements acting by affine transformations.

  19. Effect of Ultrasonic Peening and Accelerated Corrosion Exposure on the Residual Stress Distribution in Welded Marine Steel

    NASA Astrophysics Data System (ADS)

    Ahmad, Bilal; Fitzpatrick, Michael E.

    2015-03-01

    Specimens of DH36 marine steel were prepared with welded attachments. Residual stress measurements were made on the samples as-welded, following an ultrasonic peening treatment, and following accelerated corrosion exposure after ultrasonic peening. Neutron diffraction and the contour method were used for determining the residual stress profiles. The welding introduces tensile near-surface residual stress, approaching the material yield strength, and the ultrasonic peening overlays this with a compressive residual stress. Material removal by corrosion decreases the peak surface compressive stress slightly, by removal of a layer of stressed material, but does not cause significant redistribution of the residual stress profile.

  20. Taking Advantage of a Corrosion Problem to Solve a Pollution Problem

    ERIC Educational Resources Information Center

    Palomar-Ramirez, Carlos F.; Bazan-Martinez, Jose A.; Palomar-Pardave, Manuel E.; Romero-Romo, Mario A.; Ramirez-Silva, Maria Teresa

    2011-01-01

    Some simple chemistry is used to demonstrate how Fe(II) ions, formed during iron corrosion in acid aqueous solution, can reduce toxic Cr(VI) species, forming soluble Cr(III) and Fe(III) ions. These ions, in turn, can be precipitated by neutralizing the solution. The procedure provides a treatment for industrial wastewaters commonly found in…

  1. Cosmetic corrosion of painted aluminum and steel automotive body sheet: Results from outdoor and accelerated laboratory test methods

    SciTech Connect

    Moran, J.P.; Ziman, P.R.; Egbert, M.W.

    1995-11-01

    In recent years, increasing attention has been given to the need to develop an accelerated laboratory test method(s) for cosmetic corrosion of painted panels that realistically simulate in-service exposure. Much of that work has focused on steel substrates. The purpose of this research is to compare the corrosion performance of painted aluminum and steel sheet as determined om various laboratory methods and in-service exposure, and to develop a realistic accelerated test method for evaluation of the cosmetic corrosion of painted aluminum. Several aluminum sheet products from the 2xxx, 5xxx, and 6xxx alloy series have been tested. The steel substrates are similar to those used in other programs. The test methods chosen represent a cross-section of methods common to the automotive and aluminum industries for evaluation of painted sheet metal products. The results indicate that there is considerable difference in the relative correlation of various test methods to in-service exposure. In addition, there is considerable difference in the relative magnitudes and morphologies of corrosion, and occasionally in the relative rankings, as a function of test method. The influence of alloy composition and zinc phosphate coating weight are also discussed.

  2. Knowledge discovery from case histories of corrosion problems

    SciTech Connect

    Roberge, P.R.; Tullmin, M.A.A.; Trethewey, K.R.

    1997-12-01

    A successful failure analysis organization has to provide the fastest possible turn around time on incoming contract work. A common problem experienced by less experienced failure analysis staff is to identify the actual cause(s) of a failure, rather than merely the mechanism of failure, and to make recommendations for avoiding future failures. Such recommendations are often the ultimate client need and the most important component of an investigation. The proficiency and confidence levels of staff in meeting this challenge should improve considerably with the aid of advice gained from previous cases. Even with a solid client base, it is relatively difficult to provide failure analysis services on a profitable basis. The costs of employing the expert and support staff have to be covered, together with capital invested in sophisticated laboratory equipment (such as scanning electron microscopes), running costs and overheads, Even a slight improvement in the efficiency of performing any of the steps of a failure analysis process thus has the potential to make a positive difference. The value of Knowledge Discovery (KD) for knowledge reuse should also be considered in the context of staff turnover, retirements or retrenchments of experienced senior personnel, the promotion of senior technical personnel to managerial positions and staff on leave.

  3. Development of an Accelerated Test Method for the Determination of Susceptibility to Atmospheric Corrosion

    NASA Technical Reports Server (NTRS)

    Ambrose, John R.

    1991-01-01

    The theoretical rationale is presented for use of a repetitive cyclic current reversal voltammetric technique for characterization of localized corrosion processes, including atmospheric corrosion. Applicability of this proposed experimental protocol is applied to characterization of susceptibility to crevice and pitting corrosion, atmospheric corrosion and stress corrosion cracking. Criteria upon which relative susceptibility is based were determined and tested using two iron based alloys commonly in use at NASA-Kennedy; A36 (a low carbon steel) and 4130 (a low alloy steel). Practicality of the procedure was demonstrated by measuring changes in anodic polarization behavior during high frequency current reversal cycles of 25 cycles per second with 1 mA/sq cm current density amplitude in solutions containing Cl anions. The results demonstrated that, due to excessive polarization which affects conductivity of barrier corrosion product layers, A36 was less resistant to atmospheric corrosion than its 4130 counterpart; behavior which was also demonstrated during exposure tests.

  4. Pipe degradation investigations for optimization of flow-accelerated corrosion inspection location selection

    SciTech Connect

    Chandra, S.; Habicht, P.; Chexal, B.; Mahini, R.; McBrine, W.; Esselman, T.; Horowitz, J.

    1995-12-01

    A large amount of piping in a typical nuclear power plant is susceptible to Flow-Accelerated Corrosion (FAC) wall thinning to varying degrees. A typical PAC monitoring program includes the wall thickness measurement of a select number of components in order to judge the structural integrity of entire systems. In order to appropriately allocate resources and maintain an adequate FAC program, it is necessary to optimize the selection of components for inspection by focusing on those components which provide the best indication of system susceptibility to FAC. A better understanding of system FAC predictability and the types of FAC damage encountered can provide some of the insight needed to better focus and optimize the inspection plan for an upcoming refueling outage. Laboratory examination of FAC damaged components removed from service at Northeast Utilities` (NU) nuclear power plants provides a better understanding of the damage mechanisms involved and contributing causes. Selected results of this ongoing study are presented with specific conclusions which will help NU to better focus inspections and thus optimize the ongoing FAC inspection program.

  5. Fiber optic approach for detecting corrosion

    NASA Astrophysics Data System (ADS)

    Kostecki, Roman; Ebendorff-Heidepriem, Heike; Davis, Claire; McAdam, Grant; Wang, Tianyu; Monro, Tanya M.

    2016-04-01

    Corrosion is a multi-billion dollar problem faced by industry. The ability to monitor the hidden metallic structure of an aircraft for corrosion could result in greater availability of existing aircraft fleets. Silica exposed-core microstructured optical fiber sensors are inherently suited towards this application, as they are extremely lightweight, robust, and suitable both for distributed measurements and for embedding in otherwise inaccessible corrosion-prone areas. By functionalizing the fiber with chemosensors sensitive to corrosion by-products, we demonstrate in-situ kinetic measurements of accelerated corrosion in simulated aluminum aircraft joints.

  6. Applying nonlinear diffusion acceleration to the neutron transport k-Eigenvalue problem with anisotropic scattering

    SciTech Connect

    Willert, Jeffrey; Park, H.; Taitano, William

    2015-10-12

    High-order/low-order (or moment-based acceleration) algorithms have been used to significantly accelerate the solution to the neutron transport k-eigenvalue problem over the past several years. Recently, the nonlinear diffusion acceleration algorithm has been extended to solve fixed-source problems with anisotropic scattering sources. In this paper, we demonstrate that we can extend this algorithm to k-eigenvalue problems in which the scattering source is anisotropic and a significant acceleration can be achieved. Lastly, we demonstrate that the low-order, diffusion-like eigenvalue problem can be solved efficiently using a technique known as nonlinear elimination.

  7. On some theoretical problems of laser wake-field accelerators

    NASA Astrophysics Data System (ADS)

    Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kiriyama, H.; Koga, J. K.; Kotaki, H.; Mori, M.; Kando, M.

    2016-06-01

    Enhancement of the quality of laser wake-field accelerated (LWFA) electron beams implies the improvement and controllability of the properties of the wake waves generated by ultra-short pulse lasers in underdense plasmas. In this work we present a compendium of useful formulas giving relations between the laser and plasma target parameters allowing one to obtain basic dependences, e.g. the energy scaling of the electrons accelerated by the wake field excited in inhomogeneous media including multi-stage LWFA accelerators. Consideration of the effects of using the chirped laser pulse driver allows us to find the regimes where the chirp enhances the wake field amplitude. We present an analysis of the three-dimensional effects on the electron beam loading and on the unlimited LWFA acceleration in inhomogeneous plasmas. Using the conditions of electron trapping to the wake-field acceleration phase we analyse the multi-equal stage and multiuneven stage LWFA configurations. In the first configuration the energy of fast electrons is a linear function of the number of stages, and in the second case, the accelerated electron energy grows exponentially with the number of stages. The results of the two-dimensional particle-in-cell simulations presented here show the high quality electron acceleration in the triple stage injection-acceleration configuration.

  8. On some theoretical problems of laser wake-field accelerators

    NASA Astrophysics Data System (ADS)

    Bulanov, S. V.; Esirkepov, T. Zh.; Hayashi, Y.; Kiriyama, H.; Koga, J. K.; Kotaki, H.; Mori, M.; Kando, M.

    2016-06-01

    > Enhancement of the quality of laser wake-field accelerated (LWFA) electron beams implies the improvement and controllability of the properties of the wake waves generated by ultra-short pulse lasers in underdense plasmas. In this work we present a compendium of useful formulas giving relations between the laser and plasma target parameters allowing one to obtain basic dependences, e.g. the energy scaling of the electrons accelerated by the wake field excited in inhomogeneous media including multi-stage LWFA accelerators. Consideration of the effects of using the chirped laser pulse driver allows us to find the regimes where the chirp enhances the wake field amplitude. We present an analysis of the three-dimensional effects on the electron beam loading and on the unlimited LWFA acceleration in inhomogeneous plasmas. Using the conditions of electron trapping to the wake-field acceleration phase we analyse the multi-equal stage and multiuneven stage LWFA configurations. In the first configuration the energy of fast electrons is a linear function of the number of stages, and in the second case, the accelerated electron energy grows exponentially with the number of stages. The results of the two-dimensional particle-in-cell simulations presented here show the high quality electron acceleration in the triple stage injection-acceleration configuration.

  9. Accelerated corrosion testing, evaluation and durability design of bonded post-tensioned concrete tendons

    NASA Astrophysics Data System (ADS)

    Salas Pereira, Ruben Mario

    2003-06-01

    In the last few years, the effectiveness of cement grout in galvanized or polyethylene ducts, the most widely used corrosion protection system for multistrand bonded post-tensioned concrete tendons, has been under debate, due to significant tendon corrosion damage, several reported failures of individual tendons as well as a few collapses of non-typical structures. While experience in the USA has been generally good, some foreign experience has been less than satisfactory. This dissertation is part of a comprehensive research program started in 1993, which has the objectives to examine the use of post-tensioning in bridge substructures, identify durability concerns and existing technology, develop and carry out an experimental testing program, and conclude with durability design guidelines. Three experimental programs were developed: A long term macrocell corrosion test series, to investigate corrosion protection for internal tendons in precast segmental construction; a long term beam corrosion test series, to examine the effects of post-tensioning on corrosion protection as affected by crack width; and, a long term column corrosion test series, to examine corrosion protection in vertical elements. Preliminary design guidelines were developed previously in the overall study by the initial researchers, after an extensive literature review. This dissertation scope includes continuation of exposure testing of the macrocell, beam and column specimens, performing comprehensive autopsies of selected specimens and updating the durability design guidelines based on the exposure testing and autopsy results. After autopsies were performed, overall findings indicate negative durability effects due to the use of mixed reinforcement, small concrete covers, galvanized steel ducts, and industry standard or heat-shrink galvanized duct splices. The width of cracks was shown to have a direct negative effect on specimen performance. Grout voids were found to be detrimental to the

  10. PRINCIPLES OF CORROSION AND CORROSION MONITORING

    EPA Science Inventory

    Recent amendments to the National Interim Primary Drinking Water Regulations deal with corrosion and require utilities to assess corrosion in their distribution and home plumbing systems. Problems caused by corrosion can be grouped into 3 categories: health, aesthetics and econom...

  11. Investigation of Accelerated Casing Corrosion in Two Wells at Waste Management Area A-AX

    SciTech Connect

    Brown, Christopher F.; Serne, R. Jeffrey; Schaef, Herbert T.; Williams, Bruce A.; Valenta, Michelle M.; Legore, Virginia L.; Lindberg, Michael J.; Geiszler, Keith N.; Baum, Steven R.; Kutnyakov, Igor V.; Vickerman, Tanya S.; Clayton, Ray E.

    2008-09-11

    This report was revised in September 2008 to remove acid-extractable sodium data from Tables 3.13 and 3.14. The sodium data was removed due to potential contamination introduced during the acid extraction process. The rest of the text remains unchanged from the original report issued in August 2005. An overall goal of the Groundwater Performance Assessment Project, led by Pacific Northwest National Laboratory (PNNL) and per guidance in DOE Order 5400.1, includes characterizing and defining trends in the physical, chemical, and biological condition of the environment. To meet these goals, numerous Resource Conservation and Recovery Act (RCRA) monitoring wells have been installed throughout the Hanford Site. In 2003, it was determined that two RCRA monitoring wells (299-E24-19 and 299-E25-46) in Waste Management Area (WMA) A-AX failed due to rapid corrosion of the stainless steel casing over a significant length of the wells. Complete casing corrosion occurred between 276.6 and 277.7 feet below ground surface (bgs) in well 299- E24-19 and from 274.4 to 278.6 feet bgs in well 299-E25-46. CH2M HILL Hanford Group, Inc., asked scientists from PNNL to perform detailed analyses of vadose zone sediment samples collected in the vicinity of the WMA A-AX from depths comparable to those where the rapid corrosion occurred in hopes of ascertaining the cause of the rapid corrosion.

  12. Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity.

    PubMed

    Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J

    2015-09-01

    Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4-7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo. PMID:25634122

  13. Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

    PubMed Central

    Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J

    2015-01-01

    Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4–7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo. PMID:25634122

  14. Transformation Theory, Accelerating Frames, and Two Simple Problems

    ERIC Educational Resources Information Center

    Schmid, G. Bruno

    1977-01-01

    Presents an operator which transforms quantum functions to solve problems of the stationary state wave functions for a particle and the motion and spreading of a Gaussian wave packet in uniform gravitational fields. (SL)

  15. An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments. Technical Progress Report

    SciTech Connect

    Lumsden, Jesse

    1999-01-01

    OAK-B135 An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments. Technical Progress Report. This program focuses on understanding the mechanisms causing corrosion damage to steam generator tubes in a pressurized water reactor (PWR) and the effects of the proposed remedial measures. The crevice formed by the tube/tube support plate (T/TSP) intersection in a PWR steam generator is a concentration site for nonvolatile impurities (referred to as hideout) in the steam generator water. The restricted mass transport in the small crevice volume prevents the species, which concentrate during the generation of steam, from quickly dispersing into the bulk water. The concentrated solutions in crevices have been a contributing cause of several forms of corrosion of steam generator tubes including intergranular attack/stress corrosion cracking (IGA/SCC), pitting, and wastage.

  16. Problems Caused by Microbes and Treatment Strategies: Identification of H2S-Producing Bacteria in Corrosion Product of a Gas Pipeline

    NASA Astrophysics Data System (ADS)

    Lutterbach, Márcia T. S.; Contador, Luciana S.

    Microbiologically influenced corrosion (MIC) is characterised by material degradation through the action of microorganisms that can act as accelerators or inducers of the reactions of the electrochemical corrosion process. The corrosion study occurred in the past under an essentially abiotic approach, involving chemical and electrochemical experiments. This approach prevented for many years the proper interpretation of MIC phenomena and our understanding of these processes (Videla, 1991). Today, this type of corrosion receives more attention, arousing great industrial interest, since few industries are free of the occurrence of MIC in their systems. The costs of electrochemical corrosion in the US may reach 3.1% of gross domestic product (Koch et al., 2001). According to some estimates, MIC is responsible for around 20-30% of total corrosion costs (Javaherdashti, 1999).

  17. CMFD acceleration of spatial domain-decomposed neutron transport problems

    SciTech Connect

    Kelley, B. W.; Larsen, E. W.

    2012-07-01

    A significant limitation to parallelizing the solution of neutron transport problems is the need for sweeps across the entirety of the problem domain. Angular domain decomposition is common practice, as the equations for each direction are independent aside from their shared scattering/fission source. Accordingly, spatial domain decomposition does not naturally arise in the transport equations and is therefore less frequent in practice. In this paper, we show that a neutron transport domain can be straightforwardly divided into independent, parallelizable sweep regions, globally linked with the standard CMFD method, with an additional update equation. We verify, theoretically (via Fourier analysis) and computationally, that the convergence properties of this method are stable and nominally as rapid as standard CMFD. (authors)

  18. Corrosion of Iron by Sulfate-Reducing Bacteria: New Views of an Old Problem

    PubMed Central

    Garrelfs, Julia

    2014-01-01

    About a century ago, researchers first recognized a connection between the activity of environmental microorganisms and cases of anaerobic iron corrosion. Since then, such microbially influenced corrosion (MIC) has gained prominence and its technical and economic implications are now widely recognized. Under anoxic conditions (e.g., in oil and gas pipelines), sulfate-reducing bacteria (SRB) are commonly considered the main culprits of MIC. This perception largely stems from three recurrent observations. First, anoxic sulfate-rich environments (e.g., anoxic seawater) are particularly corrosive. Second, SRB and their characteristic corrosion product iron sulfide are ubiquitously associated with anaerobic corrosion damage, and third, no other physiological group produces comparably severe corrosion damage in laboratory-grown pure cultures. However, there remain many open questions as to the underlying mechanisms and their relative contributions to corrosion. On the one hand, SRB damage iron constructions indirectly through a corrosive chemical agent, hydrogen sulfide, formed by the organisms as a dissimilatory product from sulfate reduction with organic compounds or hydrogen (“chemical microbially influenced corrosion”; CMIC). On the other hand, certain SRB can also attack iron via withdrawal of electrons (“electrical microbially influenced corrosion”; EMIC), viz., directly by metabolic coupling. Corrosion of iron by SRB is typically associated with the formation of iron sulfides (FeS) which, paradoxically, may reduce corrosion in some cases while they increase it in others. This brief review traces the historical twists in the perception of SRB-induced corrosion, considering the presently most plausible explanations as well as possible early misconceptions in the understanding of severe corrosion in anoxic, sulfate-rich environments. PMID:24317078

  19. Attachment of Listeria monocytogenes to an austenitic stainless steel after welding and accelerated corrosion treatments.

    PubMed

    Mai, Tam L; Sofyan, Nofrijon I; Fergus, Jeffrey W; Gale, William F; Conner, Donald E

    2006-07-01

    Austenitic stainless steels, widely used in food processing, undergo microstructural changes during welding, resulting in three distinctive zones: weld metal, heat-affected zone, and base metal. This research was conducted to determine the attachment of Listeria monocytogenes in these three zones before and after exposure to a corrosive environment. All experiments were done with tungsten inert gas welding of type 304 stainless steel. The four welding treatments were large or small beads with high or low heat. After welding, all surfaces were polished to an equivalent surface finish. A 10-microl droplet of an L. monocytogenes suspension was placed on the test surfaces. After 3 h at 23 degrees C, the surfaces were washed and prepared for scanning electron microscopy, which was used to determine attachment of L. monocytogenes by counting cells remaining on each test surface. In general, bacteria were randomly distributed on each surface type. However, differences in surface area of inoculum due to differences in interfacial energy (as manifested by the contact angle) were apparent and required normalization of bacterial count data. There were no differences (P > 0.05) in numbers of bacteria on the three surface zones. However, after exposure to the corrosive medium, numbers of bacteria on the three zones were higher (P < 0.05) than those on the corresponding zones of noncorroded surfaces. For the corroded surfaces, bacterial counts on the base metal were lower (P < 0.05) than those on heat-affected and weld zones. PMID:16865881

  20. Effects of impurities in coal-derived liquids on accelerated hot corrosion of superalloys

    NASA Technical Reports Server (NTRS)

    Deadmore, D. L.; Lowell, C. E.

    1980-01-01

    A Mach 0.3 burner rig was used to determine the effects of potential coal derived liquid fuel impurity combustion of products on hot corrosion in IN-100, IN-792, IN_738, U-700, Mar M-509, and 304 stainless steel. The impurities, added as aqueous solutions to the combustor, were salts of sodium, potassium, vanadium, molybdenum, tungsten, phosphorus, and lead. Extent of attack was determined by metal consumption and compared to the effects of sodium alone. Vanadium, molybdenum, tungsten, phosphorous, and lead in combination with sodium all resulted in increased attack as compared with sodium alone at some temperatures, apparently due in large part to the extension of the formation of liquid deposits. Varying the sodium-potassium ratio had little effect for ratios less than 1:3 for which reduced, but measurable, attack was observed.

  1. Solution accelerators for large scale 3D electromagnetic inverse problems

    SciTech Connect

    Newman, Gregory A.; Boggs, Paul T.

    2004-04-05

    We provide a framework for preconditioning nonlinear 3D electromagnetic inverse scattering problems using nonlinear conjugate gradient (NLCG) and limited memory (LM) quasi-Newton methods. Key to our approach is the use of an approximate adjoint method that allows for an economical approximation of the Hessian that is updated at each inversion iteration. Using this approximate Hessian as a preconditoner, we show that the preconditioned NLCG iteration converges significantly faster than the non-preconditioned iteration, as well as converging to a data misfit level below that observed for the non-preconditioned method. Similar conclusions are also observed for the LM iteration; preconditioned with the approximate Hessian, the LM iteration converges faster than the non-preconditioned version. At this time, however, we see little difference between the convergence performance of the preconditioned LM scheme and the preconditioned NLCG scheme. A possible reason for this outcome is the behavior of the line search within the LM iteration. It was anticipated that, near convergence, a step size of one would be approached, but what was observed, instead, were step lengths that were nowhere near one. We provide some insights into the reasons for this behavior and suggest further research that may improve the performance of the LM methods.

  2. A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem

    SciTech Connect

    Willert, Jeffrey; Park, H.; Knoll, D.A.

    2014-10-01

    Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton–Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.

  3. A comparison of acceleration methods for solving the neutron transport k-eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Willert, Jeffrey; Park, H.; Knoll, D. A.

    2014-10-01

    Over the past several years a number of papers have been written describing modern techniques for numerically computing the dominant eigenvalue of the neutron transport criticality problem. These methods fall into two distinct categories. The first category of methods rewrite the multi-group k-eigenvalue problem as a nonlinear system of equations and solve the resulting system using either a Jacobian-Free Newton-Krylov (JFNK) method or Nonlinear Krylov Acceleration (NKA), a variant of Anderson Acceleration. These methods are generally successful in significantly reducing the number of transport sweeps required to compute the dominant eigenvalue. The second category of methods utilize Moment-Based Acceleration (or High-Order/Low-Order (HOLO) Acceleration). These methods solve a sequence of modified diffusion eigenvalue problems whose solutions converge to the solution of the original transport eigenvalue problem. This second class of methods is, in our experience, always superior to the first, as most of the computational work is eliminated by the acceleration from the LO diffusion system. In this paper, we review each of these methods. Our computational results support our claim that the choice of which nonlinear solver to use, JFNK or NKA, should be secondary. The primary computational savings result from the implementation of a HOLO algorithm. We display computational results for a series of challenging multi-dimensional test problems.

  4. Monitoring power plant fireside corrosion using corrosion probes

    SciTech Connect

    Covino, Bernard S., Jr.; Bullard, Sophie J.; Cramer, Stephen D.; Holcomb, Gordon R.; Ziomek-Moroz, M.

    2005-01-01

    The ability to monitor the corrosion degradation of key components in fossil fuel power plants is of utmost importance for Futuregen and ultra-supercritical power plants. Fireside corrosion occurs in the high temperature sections of energy production facilities due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Problems occur when equipment designed for either oxidizing or reducing conditions is exposed to alternating oxidizing and reducing conditions. This can happen especially near the burners. The use of low NOx burners is becoming more commonplace and can produce reducing environments that accelerate corrosion. One method of addressing corrosion of these surfaces is the use of corrosion probes to monitor when process changes cause corrosive conditions. In such a case, corrosion rate could become a process control variable that directs the operation of a coal combustion or coal gasification system. Alternatively, corrosion probes could be used to provide an indication of total metal damage and thus a tool to schedule planned maintenance outages.

  5. Solving large-scale sparse eigenvalue problems and linear systems of equations for accelerator modeling

    SciTech Connect

    Gene Golub; Kwok Ko

    2009-03-30

    The solutions of sparse eigenvalue problems and linear systems constitute one of the key computational kernels in the discretization of partial differential equations for the modeling of linear accelerators. The computational challenges faced by existing techniques for solving those sparse eigenvalue problems and linear systems call for continuing research to improve on the algorithms so that ever increasing problem size as required by the physics application can be tackled. Under the support of this award, the filter algorithm for solving large sparse eigenvalue problems was developed at Stanford to address the computational difficulties in the previous methods with the goal to enable accelerator simulations on then the world largest unclassified supercomputer at NERSC for this class of problems. Specifically, a new method, the Hemitian skew-Hemitian splitting method, was proposed and researched as an improved method for solving linear systems with non-Hermitian positive definite and semidefinite matrices.

  6. Transport synthetic acceleration for long-characteristics assembly-level transport problems

    SciTech Connect

    Zika, M.R.; Adams, M.L.

    2000-02-01

    The authors apply the transport synthetic acceleration (TSA) scheme to the long-characteristics spatial discretization for the two-dimensional assembly-level transport problem. This synthetic method employs a simplified transport operator as its low-order approximation. Thus, in the acceleration step, the authors take advantage of features of the long-characteristics discretization that make it particularly well suited to assembly-level transport problems. The main contribution is to address difficulties unique to the long-characteristics discretization and produce a computationally efficient acceleration scheme. The combination of the long-characteristics discretization, opposing reflecting boundary conditions (which are present in assembly-level transport problems), and TSA presents several challenges. The authors devise methods for overcoming each of them in a computationally efficient way. Since the boundary angular data exist on different grids in the high- and low-order problems, they define restriction and prolongation operations specific to the method of long characteristics to map between the two grids. They implement the conjugate gradient (CG) method in the presence of opposing reflection boundary conditions to solve the TSA low-order equations. The CG iteration may be applied only to symmetric positive definite (SPD) matrices; they prove that the long-characteristics discretization yields an SPD matrix. They present results of the acceleration scheme on a simple test problem, a typical pressurized water reactor assembly, and a typical boiling water reactor assembly.

  7. Corrosion/95 conference papers

    SciTech Connect

    1995-09-01

    The papers in this conference represent the latest technological advances in corrosion control and prevention. The following subject areas are covered: cathodic protection in natural waters; materials for fossil fuel combustion and conversion systems; modern problems in atmospheric corrosion; innovative ideas for controlling the decaying infrastructure; deposits and their effects on corrosion in industry; volatile high temperature and non aqueous corrosion inhibitors; corrosion of light-weight and precoated metals for automotive application; refining industry corrosion; corrosion in pulp and paper industry; arctic/cold weather corrosion; materials selection for waste incinerators and associated equipment; corrosion measurement technology; environmental cracking of materials; advancing technology in the coating industry; corrosion in gas treating; green inhibition; recent advances in corrosion control of rail equipment; velocity effects and erosion corrosion in oil and gas production; marine corrosion; corrosion of materials in nuclear systems; underground corrosion control; corrosion in potable and industrial water systems in buildings and its impact on environmental compliance; deposit related boiler tube failures; boiler systems monitoring and control; recent developments and experiences in reactive metals; microbiologically influenced corrosion; corrosion and corrosion control for steel reinforced concrete; international symposium on the use of 12 and 13 Cr stainless steels in oil and gas production environments; subsea corrosion /erosion monitoring in production facilities; fiberglass reinforced pipe and tubulars in oilfield service; corrosion control technology in power transmission and distribution; mechanisms and methods of scale and deposit control; closing the loop -- results oriented cooling system monitoring and control; and minimization of aqueous discharge.

  8. System modeling for the longitudinal beam dynamics control problem in heavy ion induction accelerators

    SciTech Connect

    Payne, A.N.

    1993-05-17

    We address the problem of developing system models that are suitable for studying the control of the longitudinal beam dynamics in induction accelerators for heavy ions. In particular, we present the preliminary results of our efforts to devise a general framework for building detailed, integrated models of accelerator systems consisting of pulsed power modular circuits, induction cells, beam dynamics, and control system elements. Such a framework will permit us to analyze and design the pulsed power modulators and the control systems required to effect precise control over the longitudinal beam dynamics.

  9. Grey transport acceleration method for time-dependent radiative transfer problems

    SciTech Connect

    Larsen, E.

    1988-10-01

    A new iterative method for solving hte time-dependent multifrequency radiative transfer equations is described. The method is applicable to semi-implicit time discretizations that generate a linear steady-state multifrequency transport problem with pseudo-scattering within each time step. The standard ''lambda'' iteration method is shown to often converge slowly for such problems, and the new grey transport acceleration (GTA) method, based on accelerating the lambda method by employing a grey, or frequency-independent transport equation, is developed. The GTA method is shown, theoretically by an iterative Fourier analysis, and experimentally by numerical calculations, to converge significantly faster than the lambda method. In addition, the GTA method is conceptually simple to implement for general differencing schemes, on either Eulerian or Lagrangian meshes. copyright 1988 Academic Press, Inc.

  10. Novel methods for aircraft corrosion monitoring

    NASA Astrophysics Data System (ADS)

    Bossi, Richard H.; Criswell, Thomas L.; Ikegami, Roy; Nelson, James; Normand, Eugene; Rutherford, Paul S.; Shrader, John E.

    1995-07-01

    Monitoring aging aircraft for hidden corrosion is a significant problem for both military and civilian aircraft. Under a Wright Laboratory sponsored program, Boeing Defense & Space Group is investigating three novel methods for detecting and monitoring hidden corrosion: (1) atmospheric neutron radiography, (2) 14 MeV neutron activation analysis and (3) fiber optic corrosion sensors. Atmospheric neutron radiography utilizes the presence of neutrons in the upper atmosphere as a source for interrogation of the aircraft structure. Passive track-etch neutron detectors, which have been previously placed on the aircraft, are evaluated during maintenance checks to assess the presence of corrosion. Neutrons generated by an accelerator are used via activation analysis to assess the presence of distinctive elements in corrosion products, particularly oxygen. By using fast (14 MeV) neutrons for the activation, portable, high intensity sources can be employed for field testing of aircraft. The third novel method uses fiber optics as part of a smart structure technology for corrosion detection and monitoring. Fiber optic corrosion sensors are placed in the aircraft at locations known to be susceptible to corrosion. Periodic monitoring of the sensors is used to alert maintenance personnel to the presence and degree of corrosion at specific locations on the aircraft. During the atmospheric neutron experimentation, we identified a fourth method referred to as secondary emission radiography (SER). This paper discusses the development of these methods.

  11. How copper corrosion can be retarded--New ways investigating a chronic problem for cellulose in paper.

    PubMed

    Ahn, Kyujin; Hofmann, Christa; Horsky, Monika; Potthast, Antje

    2015-12-10

    To better assess the stabilization effects of chemical treatments on Cu(II)-catalyzed cellulose degradation, we developed Cu(II)-containing model rag paper with typical copper corrosion characteristics using e-beam radiation. The paper can be prepared homogeneously and quickly compared to tedious pre-aging methods. Using the Cu(II)-containing model rag paper, the stabilization effects of various chemicals on Cu(II)-catalyzed degradation of cellulose were tested. Benzotriazol was highly effective in retarding the degradation of the Cu(II)-containing model rag paper under hot and humid aging condition, as well as under photo-oxidative stress. Tetrabutylammonium bromide reduced Cu(II)-catalyzed degradation of cellulose, but its efficacy was dependent on the accelerated aging conditions. The results with the alkaline treatments and gelatin treatment suggested that their roles in the degradation mechanisms of cellulose in the presence of Cu(II) differ from those of benzotriazol and tetrabutylammonium bromide. PMID:26428109

  12. Accelerated projected steepest descent method for nonlinear inverse problems with sparsity constraints

    NASA Astrophysics Data System (ADS)

    Teschke, Gerd; Borries, Claudia

    2010-02-01

    This paper is concerned with the construction of an iterative algorithm to solve nonlinear inverse problems with an ell1 constraint on x. One extensively studied method to obtain a solution of such an ell1 penalized problem is iterative soft-thresholding. Regrettably, such iteration schemes are computationally very intensive. A subtle alternative to iterative soft-thresholding is the projected gradient method that was quite recently proposed by Daubechies et al (2008 J. Fourier Anal. Appl. 14 764-92). The authors have shown that the proposed scheme is indeed numerically much thriftier. However, its current applicability is limited to linear inverse problems. In this paper we provide an extension of this approach to nonlinear problems. Adequately adapting the conditions on the (variable) thresholding parameter to the nonlinear nature, we can prove convergence in norm for this projected gradient method, with and without acceleration. A numerical verification is given in the context of nonlinear and non-ideal sensing. For this particular recovery problem we can achieve an impressive numerical performance (when comparing it to non-accelerated procedures).

  13. A theoretical perspective on particle acceleration by interplanetary shocks and the Solar Energetic Particle problem

    NASA Astrophysics Data System (ADS)

    Verkhoglyadova, Olga P.; Zank, Gary P.; Li, Gang

    2015-02-01

    Understanding the physics of Solar Energetic Particle (SEP) events is of importance to the general question of particle energization throughout the cosmos as well as playing a role in the technologically critical impact of space weather on society. The largest, and often most damaging, events are the so-called gradual SEP events, generally associated with shock waves driven by coronal mass ejections (CMEs). We review the current state of knowledge about particle acceleration at evolving interplanetary shocks with application to SEP events that occur in the inner heliosphere. Starting with a brief outline of recent theoretical progress in the field, we focus on current observational evidence that challenges conventional models of SEP events, including complex particle energy spectra, the blurring of the distinction between gradual and impulsive events, and the difference inherent in particle acceleration at quasi-parallel and quasi-perpendicular shocks. We also review the important problem of the seed particle population and its injection into particle acceleration at a shock. We begin by discussing the properties and characteristics of non-relativistic interplanetary shocks, from their formation close to the Sun to subsequent evolution through the inner heliosphere. The association of gradual SEP events with shocks is discussed. Several approaches to the energization of particles have been proposed, including shock drift acceleration, diffusive shock acceleration (DSA), acceleration by large-scale compression regions, acceleration by random velocity fluctuations (sometimes known as the "pump mechanism"), and others. We review these various mechanisms briefly and focus on the DSA mechanism. Much of our emphasis will be on our current understanding of the parallel and perpendicular diffusion coefficients for energetic particles and models of plasma turbulence in the vicinity of the shock. Because of its importance both to the DSA mechanism itself and to the particle

  14. Corrosion sensor

    DOEpatents

    Glass, R.S.; Clarke, W.L. Jr.; Ciarlo, D.R.

    1994-04-26

    A corrosion sensor array is described incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis. 7 figures.

  15. Corrosion sensor

    DOEpatents

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1994-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  16. Solving Large Scale Nonlinear Eigenvalue Problem in Next-Generation Accelerator Design

    SciTech Connect

    Liao, Ben-Shan; Bai, Zhaojun; Lee, Lie-Quan; Ko, Kwok; /SLAC

    2006-09-28

    A number of numerical methods, including inverse iteration, method of successive linear problem and nonlinear Arnoldi algorithm, are studied in this paper to solve a large scale nonlinear eigenvalue problem arising from finite element analysis of resonant frequencies and external Q{sub e} values of a waveguide loaded cavity in the next-generation accelerator design. They present a nonlinear Rayleigh-Ritz iterative projection algorithm, NRRIT in short and demonstrate that it is the most promising approach for a model scale cavity design. The NRRIT algorithm is an extension of the nonlinear Arnoldi algorithm due to Voss. Computational challenges of solving such a nonlinear eigenvalue problem for a full scale cavity design are outlined.

  17. Dark energy in modified Gauss-Bonnet gravity: Late-time acceleration and the hierarchy problem

    SciTech Connect

    Cognola, Guido; Zerbini, Sergio; Elizalde, Emilio; Nojiri, Shin'ichi; Odintsov, Sergei D.

    2006-04-15

    Dark energy cosmology is considered in a modified Gauss-Bonnet (GB) model of gravity where an arbitrary function of the GB invariant, f(G), is added to the general relativity action. We show that a theory of this kind is endowed with a quite rich cosmological structure: it may naturally lead to an effective cosmological constant, quintessence, or phantom cosmic acceleration, with a possibility for the transition from deceleration to acceleration. It is demonstrated in the paper that this theory is perfectly viable, since it is compliant with the solar system constraints. Specific properties of f(G) gravity in a de Sitter (dS) universe, such as dS and SdS solutions, their entropy, and its explicit one-loop quantization are studied. The issue of a possible solution of the hierarchy problem in modified gravities is also addressed.

  18. Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Li, Wenyan; Buhrow, Jerry; Zhang, Xuejun; Surma, Jan; Fitzpatrick, Lilly; Montgomery, Eliza; Calle, Luz Marina

    2014-01-01

    Research efforts are under way to replace current corrosion inhibitors with more environmentally friendly alternatives. However, problems with corrosion inhibition efficiency, coating compatibility and solubility have hindered the use of many of these materials as simple pigment additives.This paper will present technical details on how the Corrosion Technology Lab at NASAs Kennedy Space Center (KSC) has addressed these issues by encapsulating environmentally friendly inhibitors into organic and inorganic microparticles and microcapsules. The synthetic process for polymer particles was characterized and post-synthesis analysis was performed to determine the interactions between the inhibitors and the encapsulation material. The pH-controlled release of inhibitors from various particle formulations in aqueous base was monitored and compared to both electrochemical and salt immersion accelerated corrosion experiment. Furthermore, synergistic corrosion inhibition effects observed during the corrosion testing of several inhibitor combinations will be presented.

  19. VARIATIONAL APPROACH IN WAVELET FRAMEWORK TO POLYNOMIAL APPROXIMATIONS OF NONLINEAR ACCELERATOR PROBLEMS

    SciTech Connect

    FEDOROVA,A.; ZEITLIN,M.; PARSA,Z.

    2000-03-31

    In this paper the authors present applications of methods from wavelet analysis to polynomial approximations for a number of accelerator physics problems. According to a variational approach in the general case they have the solution as a multiresolution (multiscales) expansion on the base of compactly supported wavelet basis. They give an extension of their results to the cases of periodic orbital particle motion and arbitrary variable coefficients. Then they consider more flexible variational method which is based on a biorthogonal wavelet approach. Also they consider a different variational approach, which is applied to each scale.

  20. A precorrected-FFT method to accelerate the solution of the forward problem in magnetoencephalography

    NASA Astrophysics Data System (ADS)

    Tissari, Satu; Rahola, Jussi

    2003-02-01

    Accurate localization of brain activity recorded by magnetoencephalography (MEG) requires that the forward problem, i.e. the magnetic field caused by a dipolar source current in a homogeneous volume conductor, be solved precisely. We have used the Galerkin method with piecewise linear basis functions in the boundary element method to improve the solution of the forward problem. In addition, we have replaced the direct method, i.e. the LU decomposition, by a modern iterative method to solve the dense linear system of equations arising from the boundary element discretization. In this paper we describe a precorrected-FFT method which we have combined with the iterative method to accelerate the solution of the forward problem and to avoid the explicit formation of the dense coefficient matrix. For example, with a triangular mesh of 18000 triangles, the CPU time to solve the forward problem was decreased from 3.5 h to less than 5 min, and the computer memory requirements were decreased from 1.3 GB to 156 MB. The method makes it possible to solve quickly significantly larger problems with widely-used workstations.

  1. Accelerated solution of non-linear flow problems using Chebyshev iteration polynomial based RK recursions

    SciTech Connect

    Lorber, A.A.; Carey, G.F.; Bova, S.W.; Harle, C.H.

    1996-12-31

    The connection between the solution of linear systems of equations by iterative methods and explicit time stepping techniques is used to accelerate to steady state the solution of ODE systems arising from discretized PDEs which may involve either physical or artificial transient terms. Specifically, a class of Runge-Kutta (RK) time integration schemes with extended stability domains has been used to develop recursion formulas which lead to accelerated iterative performance. The coefficients for the RK schemes are chosen based on the theory of Chebyshev iteration polynomials in conjunction with a local linear stability analysis. We refer to these schemes as Chebyshev Parameterized Runge Kutta (CPRK) methods. CPRK methods of one to four stages are derived as functions of the parameters which describe an ellipse {Epsilon} which the stability domain of the methods is known to contain. Of particular interest are two-stage, first-order CPRK and four-stage, first-order methods. It is found that the former method can be identified with any two-stage RK method through the correct choice of parameters. The latter method is found to have a wide range of stability domains, with a maximum extension of 32 along the real axis. Recursion performance results are presented below for a model linear convection-diffusion problem as well as non-linear fluid flow problems discretized by both finite-difference and finite-element methods.

  2. GPU accelerated solver for nonlinear reaction-diffusion systems. Application to the electrophysiology problem

    NASA Astrophysics Data System (ADS)

    Mena, Andres; Ferrero, Jose M.; Rodriguez Matas, Jose F.

    2015-11-01

    Solving the electric activity of the heart possess a big challenge, not only because of the structural complexities inherent to the heart tissue, but also because of the complex electric behaviour of the cardiac cells. The multi-scale nature of the electrophysiology problem makes difficult its numerical solution, requiring temporal and spatial resolutions of 0.1 ms and 0.2 mm respectively for accurate simulations, leading to models with millions degrees of freedom that need to be solved for thousand time steps. Solution of this problem requires the use of algorithms with higher level of parallelism in multi-core platforms. In this regard the newer programmable graphic processing units (GPU) has become a valid alternative due to their tremendous computational horsepower. This paper presents results obtained with a novel electrophysiology simulation software entirely developed in Compute Unified Device Architecture (CUDA). The software implements fully explicit and semi-implicit solvers for the monodomain model, using operator splitting. Performance is compared with classical multi-core MPI based solvers operating on dedicated high-performance computer clusters. Results obtained with the GPU based solver show enormous potential for this technology with accelerations over 50 × for three-dimensional problems.

  3. Acceleration of multiple solution of a boundary value problem involving a linear algebraic system

    NASA Astrophysics Data System (ADS)

    Gazizov, Talgat R.; Kuksenko, Sergey P.; Surovtsev, Roman S.

    2016-06-01

    Multiple solution of a boundary value problem that involves a linear algebraic system is considered. New approach to acceleration of the solution is proposed. The approach uses the structure of the linear system matrix. Particularly, location of entries in the right columns and low rows of the matrix, which undergo variation due to the computing in the range of parameters, is used to apply block LU decomposition. Application of the approach is considered on the example of multiple computing of the capacitance matrix by method of moments used in numerical electromagnetics. Expressions for analytic estimation of the acceleration are presented. Results of the numerical experiments for solution of 100 linear systems with matrix orders of 1000, 2000, 3000 and different relations of variated and constant entries of the matrix show that block LU decomposition can be effective for multiple solution of linear systems. The speed up compared to pointwise LU factorization increases (up to 15) for larger number and order of considered systems with lower number of variated entries.

  4. Fighting Corrosion

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Reinforced concrete structures such as bridges, parking decks, and balconies are designed to have a service life of over 50 years. All too often, however, many structures fall short of this goal, requiring expensive repairs and protection work earlier than anticipated. The corrosion of reinforced steel within the concrete infrastructure is a major cause for this premature deterioration. Such corrosion is a particularly dangerous problem for the facilities at NASA s Kennedy Space Center. Located near the Atlantic Ocean in Florida, Kennedy is based in one of the most corrosive-prone areas in the world. In order to protect its launch support structures, highways, pipelines, and other steel-reinforced concrete structures, Kennedy engineers developed the Galvanic Liquid Applied Coating System. The system utilizes an inorganic coating material that slows or stops the corrosion of reinforced steel members inside concrete structures. Early tests determined that the coating meets the criteria of the National Association of Corrosion Engineers for complete protection of steel rebar embedded in concrete. Testing is being continued at the Kennedy's Materials Science Beach Corrosion Test Site.

  5. Influence of Cl- Deposition Content on Corrosion of LY12

    NASA Astrophysics Data System (ADS)

    Han, Desheng; Li, Di; Zheng, Tianliang

    A series of accelerated corrosion tests were conducted in the simulated marine atmosphere environment to study the corrosion of LY12 aluminum alloy under different Cl- deposition content. The change of corrosion morphology, weight gain and electrochemical parameters (Corrosion Electric Potential, AC Impedance) were inspected in the corrosion course. The different corrosion behaviors caused by the variation of Cl- deposition content were also discussed.

  6. Are biologic treatments a potential approach to wear- and corrosion-related problems?

    PubMed

    Smith, R Lane; Schwarz, Edward M

    2014-12-01

    WHERE ARE WE NOW?: Biological treatments, defined as any nonsurgical intervention whose primary mechanism of action is reducing the host response to wear and/or corrosion products, have long been postulated as solutions for osteolysis and aseptic loosening of total joint arthroplasties. Despite extensive research on drugs that target the inflammatory, osteoclastic, and osteogenic responses to wear debris, no biological treatment has emerged as an approved therapy. We review the extensive preclinical research and modest clinical research to date, which has led to the central conclusion that the osteoclast is the primary target. We also allude to the significant changes in health care, unabated safety concerns about chronic immunosuppressive/antiinflammatory therapies, industry's complete lack of interest in developing an intervention for this condition, and the practical issues that have narrowly focused the possibilities for a biologic treatment for wear debris-induced osteolysis. WHERE DO WE NEED TO GO?: Based on the conclusions from research, and the economic, regulatory, and practical issues that limit the future directions toward the development of a biologic treatment, there are a few rational approaches that warrant investigation. These largely focus on FDA-approved osteoporosis therapies that target the osteoclast (bisphosphonates and anti-RANK ligand) and recombinant parathyroid hormone (teriparatide) prophylactic treatment to increase osseous integration of the prosthesis to overcome high-risk susceptibility to aseptic loosening. The other roadblock that must be overcome if there is to be an approved biologic therapy to prevent the progression of periprosthetic osteolysis and aseptic loosening is the development of radiological measures that can quantify a significant drug effect in a randomized, placebo-controlled clinical trial. We review the progress of volumetric quantification of osteolysis in animal studies and clinical pilots. HOW DO WE GET THERE

  7. SOLVING A COPPER CORROSION PROBLEM WITH ORTHOPHOSPHATE: INDIAN HILL, OHIO CASE STUDY

    EPA Science Inventory

    Many small and medium-sized water systems have troublt complying with the copper Action Level (of the Lead and Copper Rule), sometimes concurrently with meeting the lead Action level. The problem is especially troubling and widespread with ground water supplies having high alkali...

  8. Microbial problems in connection with storage of jet fuel in rock caverns. Methods to inhibit development of corrosive fuel. Mikrobiella problem vid bergrumslagring av jetbraensle. Inhiberingsmetoder foer att foerhindra uppkomst av korrosivt braensle

    SciTech Connect

    Norqvist, A.; Edlund, A.; Roffey

    1986-04-01

    Problems with long-term storage of jet fuel in rock caverns have during the last years been observed. The problems have mainly been concerned with the accumulation of corrosive compounds in the fuel. Studies in laboratory model systems were carried out in order to understand which factors are important in causing the problems. The rate of groundwater leaking in, the oxygen and sulfate concentration in the bedwater, the amount of sediment, and the temperature were shown to be some of the more-important factors. With the aim to find some suitable methods to prevent the problems from arising, studies in model systems were also carried out. Oxygenation of the bedwater or addition of a biodegradable biocide gave positive effects resulting in reduction of microbial activities and no development of corrosive fuel.

  9. Simulations of second-order Fermi acceleration of electrons: Solving the injection problem

    SciTech Connect

    Gisler, G.R.

    1991-12-31

    The boosting of electrons from a Maxwellian distribution into a suprathermal power-law tail has long been recognized as an important bottleneck governing the subsequent acceleration of some of these electrons to relativistic energies. This is the seed or injection problem. I study this boosting process using a test-particle simulation code, following the full equations of motion of tens of thousands of electrons chosen from a thermal population as they move through general time-dependent magnetic fields. Inhomogeneities in the magnetic field are provided by finite swarms of moving current loops with Maxwellian velocity distributions and power-law distributions of loop size and dipole moment strength. Whether bulk heating or boosting occurs is found to depend on the size of the swarm thermal speed compared to the electron thermal speed. When the swarm thermal speed is comparable to the electron thermal speed the entire electron population is heated by encounters with the rapidly moving current loops, approximately preserving the Maxwellian character of the electron distribution. On the other hand, at very low swarm thermal speeds there is no bulk heating; instead one percent or fewer of the electrons are boosted into a power-law suprathermal tail with a differential energy spectral index between 1 and 2. Individual boosts of 2000 and more have been observed in samples of 50,000 electrons. Most of the strongly boosted electrons have initial energies that are well below the peak of the initial Maxwellian.

  10. PRINCIPLES OF INTERNAL CORROSION AND CORROSION MONITORING

    EPA Science Inventory

    Corrosion, a complex electrochemical phenomenon that cannot always be eliminated but can usually be controlled in a cost-effective manner, may be uniform and attack a surface evenly or may cause severe localized problems such as a crevice or pit. For the corrosion reaction to pro...

  11. Accelerated forgetting? An evaluation on the use of long-term forgetting rates in patients with memory problems

    PubMed Central

    Geurts, Sofie; van der Werf, Sieberen P.; Kessels, Roy P. C.

    2015-01-01

    The main focus of this review was to evaluate whether long-term forgetting rates (delayed tests, days, to weeks, after initial learning) are more sensitive measures than standard delayed recall measures to detect memory problems in various patient groups. It has been suggested that accelerated forgetting might be characteristic for epilepsy patients, but little research has been performed in other populations. Here, we identified eleven studies in a wide range of brain injured patient groups, whose long-term forgetting patterns were compared to those of healthy controls. Signs of accelerated forgetting were found in three studies. The results of eight studies showed normal forgetting over time for the patient groups. However, most of the studies used only a recognition procedure, after optimizing initial learning. Based on these results, we recommend the use of a combined recall and recognition procedure to examine accelerated forgetting and we discuss the relevance of standard and optimized learning procedures in clinical practice. PMID:26106343

  12. Accelerated forgetting? An evaluation on the use of long-term forgetting rates in patients with memory problems.

    PubMed

    Geurts, Sofie; van der Werf, Sieberen P; Kessels, Roy P C

    2015-01-01

    The main focus of this review was to evaluate whether long-term forgetting rates (delayed tests, days, to weeks, after initial learning) are more sensitive measures than standard delayed recall measures to detect memory problems in various patient groups. It has been suggested that accelerated forgetting might be characteristic for epilepsy patients, but little research has been performed in other populations. Here, we identified eleven studies in a wide range of brain injured patient groups, whose long-term forgetting patterns were compared to those of healthy controls. Signs of accelerated forgetting were found in three studies. The results of eight studies showed normal forgetting over time for the patient groups. However, most of the studies used only a recognition procedure, after optimizing initial learning. Based on these results, we recommend the use of a combined recall and recognition procedure to examine accelerated forgetting and we discuss the relevance of standard and optimized learning procedures in clinical practice. PMID:26106343

  13. Flow Accelerated Erosion-Corrosion (FAC) considerations for secondary side piping in the AP1000{sup R} nuclear power plant design

    SciTech Connect

    Vanderhoff, J. F.; Rao, G. V.; Stein, A.

    2012-07-01

    The issue of Flow Accelerated Erosion-Corrosion (FAC) in power plant piping is a known phenomenon that has resulted in material replacements and plant accidents in operating power plants. Therefore, it is important for FAC resistance to be considered in the design of new nuclear power plants. This paper describes the design considerations related to FAC that were used to develop a safe and robust AP1000{sup R} plant secondary side piping design. The primary FAC influencing factors include: - Fluid Temperature - Pipe Geometry/layout - Fluid Chemistry - Fluid Velocity - Pipe Material Composition - Moisture Content (in steam lines) Due to the unknowns related to the relative impact of the influencing factors and the complexities of the interactions between these factors, it is difficult to accurately predict the expected wear rate in a given piping segment in a new plant. This paper provides: - a description of FAC and the factors that influence the FAC degradation rate, - an assessment of the level of FAC resistance of AP1000{sup R} secondary side system piping, - an explanation of options to increase FAC resistance and associated benefits/cost, - discussion of development of a tool for predicting FAC degradation rate in new nuclear power plants. (authors)

  14. Tunneling corrosion mechanism of 25% chromium-20% nickel-niobium stainless steel in highly oxidizing nitric acid

    SciTech Connect

    Kajimura, H.; Harada, M.; Okada, T.; Nagano, H.; Okubo, M.

    1995-07-01

    Austenitic stainless steel (SS) is used commonly in chemical plants dealing with nitric acid (HNO{sub 3}) because of its high corrosion resistance. However, even SS tends to corrode intergranularly in highly oxidizing HNO{sub 3} containing oxidizing chromium or cerium ions, such as Cr{sup 6+} or Ce{sup 4+}. Furthermore, pitting corrosion, so-called tunneling corrosion or end-grain attack, occurs on the forgings in highly oxidizing HNO{sub 3}. The mechanism of tunneling corrosion and its countermeasures for a 25% Cr-20% Ni-Nb steel (UNS S31040) in a mock reprocessing plant were studied. Results indicated tunneling corrosion was a type of pitting corrosion with general and intergranular attack on pit surfaces. It propagated along metal flows with penetrations up to 2 mm in diameter and 6 mm in depth. Rates of tunneling corrosion were 3 to 13 times faster than general corrosion. Tunneling corrosion initiated and propagated parallel to metal flows on the local parts where chromium content was depleted. This method of corrosion was caused both by preferential corrosion of a low-chromium part and corrosion accelerated by the galvanic action between a low-chromium part as an anode and a high-chromium part as a cathode. The electroslag remelting process completely resolved this problem by making ingots free from continuous chromium segregation.

  15. Study on the radiation problem caused by electron beam loss in accelerator tubes

    NASA Astrophysics Data System (ADS)

    Li, Quan-Feng; Guo, Bing-Qi; Zhang, Jie-Xi; Chen, Huai-Bi

    2008-07-01

    The beam dynamic code PARMELA was used to simulate the transportation process of accelerating electrons in S-band SW linacs with different energies of 2.5, 6 and 20 MeV. The results indicated that in the ideal condition, the percentage of electron beam loss was 50% in accelerator tubes. Also we calculated the spectrum, the location and angular distribution of the lost electrons. Calculation performed by Monte Carlo code MCNP demonstrated that the radiation distribution of lost electrons was nearly uniform along the tube axis, the angular distributions of the radiation dose rates of the three tubes were similar, and the highest leaking dose was at the angle of 160° with respect to the axis. The lower the energy of the accelerator, the higher the radiation relative leakage. For the 2.5 MeV accelerator, the maximum dose rate reached 5% of the main dose and the one on the head of the electron gun was 1%, both of which did not meet the eligible protection requirement for accelerators. We adopted different shielding designs for different accelerators. The simulated result showed that the shielded radiation leaking dose rates fulfilled the requirement. Supported by National Natural Science Foundation of China (10135040)

  16. [Current problems of occupational hygiene in the manufacture and use of inhibitors of the atmospheric corrosion of metals].

    PubMed

    Paustovskaia, V V

    1994-01-01

    On the basis of the data obtained from in-plant hygienic investigations designed to study conditions of labour of employees working with the inhibitors of the metal atmospheric corrosion, acid corrosion, for two-phase systems and hydrogen sulfide corrosion, assessment of these was made in accordance with the "Hygienic classification of labour (as to the indices of health and safety hazards from exposures to factors of an employee's occupational environment, hardness and strenuousness of the work process"), 1986. Degree of hardness of the job done by the workmen engaged in the production and application of the inhibitors in different branches of national economy was assessed. Hygienic and treatment-and-prophylactic requirements were substantiated. PMID:7900368

  17. The problems of mass transfer and formation of deposits of corrosion products on fuel assemblies of a VVER-1200 reactor

    NASA Astrophysics Data System (ADS)

    Rodionov, Yu. A.; Kritskii, V. G.; Berezina, I. G.; Gavrilov, A. V.

    2014-03-01

    On the basis of examination of materials published both in Russia and abroad, as well as their own investigations, the authors explain the reasons for the occurrence of such effects as AOA (Axial Offset Anomalies) and an increase in the coolant pressure difference in the core of nuclear reactors of the VVER type. To detect the occurrence of the AOA effect, the authors suggest using the specific activity of 58Co in the coolant. In the VVER-1200 design the thermohydraulic regime for fuel assemblies in the first year of their service life involves slight boiling of the coolant in the upper part of the core, which may induce the occurrence of the AOA effect, intensification of corrosion of fuel claddings, and abnormal increase in deposition of corrosion products. Radiolysis of the water coolant in the boiling section (boiling in pores of deposits) may intensify not only general corrosion but also a localized (nodular) one. As a result of intensification of the corrosion processes and growth of deposits, deterioration of the radiation situation in the rooms of the primary circuit of a VVER-1200 reactor as compared to that at nuclear power plants equipped with reactors of the VVER-1000 type is possible. Recommendations for preventing the AOA effect at nuclear power plants with VVER-1200 reactors on the matter of the direction of further investigations are made.

  18. Stress corrosion resistant fasteners

    NASA Technical Reports Server (NTRS)

    Roach, T. A.

    1985-01-01

    A family of high performance aerospace fasteners made from corrosion resistant alloys for use in applications where corrosion and stress-corrosion cracking are of major concern are discussed. The materials discussed are mainly A-286, Inconel 718, MP35N and MP159. Most of the fasteners utilize cold worked and aged materials to achieve the desired properties. The fasteners are unique in that they provide a combination of high strength and immunity to stress corrosion cracking not previously attainable. A discussion of fastener stress corrosion failures is presented including a review of the history and a description of the mechanism. Case histories are presented to illustrate the problems which can arise when material selection is made without proper regard for the environmental conditions. Mechanical properties and chemical compositions are included for the fasteners discussed. Several aspects of the application of high performance corrosion resistant fasteners are discussed including galvanic compatibility and torque-tension relationships.

  19. Monitoring corrosion in reinforced concrete structures

    NASA Astrophysics Data System (ADS)

    Kung, Peter; Comanici, Maria I.

    2014-06-01

    Many defects can cause deterioration and cracks in concrete; these are results of poor concrete mix, poor workmanship, inadequate design, shrinkage, chemical and environmental attack, physical or mechanical damage, and corrosion of reinforcing steel (RS). We want to develop a suite of sensors and systems that can detect that corrosion is taking place in RS and inform owners how serious the problem is. By understanding the stages of the corrosion process, we can develop special a sensor that detects each transition. First, moisture ingress can be monitored by a fiber optics humidity sensor, then ingress of Chloride, which acts as a catalyst and accelerates the corrosion process by converting iron into ferrous compounds. We need a fiber optics sensor which can quantify Chloride ingress over time. Converting ferric to ferrous causes large volume expansion and cracks. Such pressure build-up can be detected by a fiber optic pressure sensor. Finally, cracks emit acoustic waves, which can be detected by a high frequency sensor made with phase-shifted gratings. This paper will discuss the progress in our development of these special sensors and also our plan for a field test by the end of 2014. We recommend that we deploy these sensors by visually inspecting the affected area and by identifying locations of corrosion; then, work with the designers to identify spots that would compromise the integrity of the structure; finally, drill a small hole in the concrete and insert these sensors. Interrogation can be done at fixed intervals with a portable unit.

  20. Accelerated Cartesian expansions for the rapid solution of periodic multiscale problems

    DOE PAGESBeta

    Baczewski, Andrew David; Dault, Daniel L.; Shanker, Balasubramaniam

    2012-07-03

    We present an algorithm for the fast and efficient solution of integral equations that arise in the analysis of scattering from periodic arrays of PEC objects, such as multiband frequency selective surfaces (FSS) or metamaterial structures. Our approach relies upon the method of Accelerated Cartesian Expansions (ACE) to rapidly evaluate the requisite potential integrals. ACE is analogous to FMM in that it can be used to accelerate the matrix vector product used in the solution of systems discretized using MoM. Here, ACE provides linear scaling in both CPU time and memory. Details regarding the implementation of this method within themore » context of periodic systems are provided, as well as results that establish error convergence and scalability. In addition, we also demonstrate the applicability of this algorithm by studying several exemplary electrically dense systems.« less

  1. Accelerated Cartesian expansions for the rapid solution of periodic multiscale problems

    SciTech Connect

    Baczewski, Andrew David; Dault, Daniel L.; Shanker, Balasubramaniam

    2012-07-03

    We present an algorithm for the fast and efficient solution of integral equations that arise in the analysis of scattering from periodic arrays of PEC objects, such as multiband frequency selective surfaces (FSS) or metamaterial structures. Our approach relies upon the method of Accelerated Cartesian Expansions (ACE) to rapidly evaluate the requisite potential integrals. ACE is analogous to FMM in that it can be used to accelerate the matrix vector product used in the solution of systems discretized using MoM. Here, ACE provides linear scaling in both CPU time and memory. Details regarding the implementation of this method within the context of periodic systems are provided, as well as results that establish error convergence and scalability. In addition, we also demonstrate the applicability of this algorithm by studying several exemplary electrically dense systems.

  2. CORROSION PROCESS IN REINFORCED CONCRETE IDENTIFIED BY ACOUSTIC EMISSION

    NASA Astrophysics Data System (ADS)

    Kawasaki, Yuma; Kitaura, Misuzu; Tomoda, Yuichi; Ohtsu, Masayasu

    Deterioration of Reinforced Concrete (RC) due to salt attack is known as one of serious problems. Thus, development of non-destructive evaluation (NDE) techniques is important to assess the corrosion process. Reinforcement in concrete normally does not corrode because of a passive film on the surface of reinforcement. When chloride concentration at reinfo rcement exceeds the threshold level, the passive film is destroyed. Thus maintenance is desirable at an early stage. In this study, to identify the onset of corrosion and the nucleation of corrosion-induced cracking in concrete due to expansion of corrosion products, continuous acoustic emission (AE) monitoring is applied. Accelerated corrosion and cyclic wet and dry tests are performed in a laboratory. The SiGMA (Simplified Green's functions for Moment tensor Analysis) proce dure is applied to AE waveforms to clarify source kinematics of micro-cracks locations, types and orientations. Results show that the onset of corrosion and the nu cleation of corrosion-induced cracking in concrete are successfully identified. Additionally, cross-sections inside the reinforcement are observed by a scanning electron microscope (SEM). From these results, a great promise for AE techniques to monitor salt damage at an early stage in RC structures is demonstrated.

  3. Localized corrosion resistance of automotive exhaust alloys

    SciTech Connect

    Sabata, A.; Brossia, C.S.; Behling, M.

    1998-12-31

    Corrosion in automotive exhaust systems can be broadly classified as (a) cold end corrosion and (b) hot end corrosion. For the cold end, the requirements include inside-out perforation corrosion resistance and cosmetic corrosion resistance. Perforation corrosion causes noticeable degradation in noise quality and may even affect the back pressure. For the hot end, the key concern has been perforation corrosion resistance. With the use of oxygen sensors in catalytic converters, the failure criteria will become more stringent. Numerous accelerated corrosion tests have been used to rank materials for the Hot End and the Cold End. These include (a) Continuous Test, (b) Cyclic Tests -- Hot End, (c) Cyclic Tests -- Cold End, (d) Electrochemical Ranking. In this paper the authors evaluate some of the commonly used exhaust materials in these accelerated tests. These accelerated tests are easy to use, inexpensive to run as compared to proving ground testing or trailer testing and can provide information in a relatively short time. Here they report lab work to date on some of the accelerated corrosion testing for perforation corrosion resistance. Note that these tests are useful for ranking materials only. Life expectancy of the material can be given only after a correlation is established between the accelerated tests and field performance. The electrochemical tests were designed to gain insight into pit growth kinetics in the accelerated tests.

  4. An exact algorithm for the maximum clique problem with accelerated pruning

    SciTech Connect

    Pardalos, P.; Gibbons, L.; Hearn, D.

    1994-12-31

    We present an exact partial enumerative algorithm for the maximum clique problem. The pruning device used is derived from graph colorings. Pruning of the search tree is accomplished not only by the number of colors used to color a tree subproblem but also by using information gained in the process of coloring. This leads to increased pruning which translates into improved computational performance. Experimental results on test problems are presented.

  5. ADHD as risk factor for early onset and heightened adult problem severity of illicit substance use: An Accelerated Gateway Model

    PubMed Central

    Dunne, Eugene M.; Hearn, Lauren E.; Rose, Jonathan; Latimer, William W.

    2014-01-01

    The primary aims of the present study were to assess ADHD history as a risk factor for earlier initiation and current use of licit and illicit substances among a sample of drug using adults. It was hypothesized that ADHD history would accelerate the Gateway Theory of drug use. Participants included 941 drug-using African American and Caucasian individuals in Baltimore, Maryland. The sample consisted of 124 (13.2%) participants who reported a history of ADHD and 817 (86.8%) who reported no history of ADHD. The accelerated gateway hypothesis was supported, as a history of self-reported ADHD was significantly associated with younger ages of initiation for alcohol, cigarettes, marijuana, and cocaine use. Participants with a history of ADHD were also more likely to engage in recent HIV-risk behavior, such as injection drug use and needle sharing. This study provides compelling data in support of an accelerated gateway model for substance use related to ADHD history and increased problem severity in adulthood. Targeted substance use prevention and intervention may be beneficial for those with ADHD. PMID:25123341

  6. LCODE: A parallel quasistatic code for computationally heavy problems of plasma wakefield acceleration

    NASA Astrophysics Data System (ADS)

    Sosedkin, A. P.; Lotov, K. V.

    2016-09-01

    LCODE is a freely distributed quasistatic 2D3V code for simulating plasma wakefield acceleration, mainly specialized at resource-efficient studies of long-term propagation of ultrarelativistic particle beams in plasmas. The beam is modeled with fully relativistic macro-particles in a simulation window copropagating with the light velocity; the plasma can be simulated with either kinetic or fluid model. Several techniques are used to obtain exceptional numerical stability and precision while maintaining high resource efficiency, enabling LCODE to simulate the evolution of long particle beams over long propagation distances even on a laptop. A recent upgrade enabled LCODE to perform the calculations in parallel. A pipeline of several LCODE processes communicating via MPI (Message-Passing Interface) is capable of executing multiple consecutive time steps of the simulation in a single pass. This approach can speed up the calculations by hundreds of times.

  7. The Krylov accelerated SIMPLE(R) method for flow problems in industrial furnaces

    NASA Astrophysics Data System (ADS)

    Vuik, C.; Saghir, A.; Boerstoel, G. P.

    2000-08-01

    Numerical modeling of the melting and combustion process is an important tool in gaining understanding of the physical and chemical phenomena that occur in a gas- or oil-fired glass-melting furnace. The incompressible Navier-Stokes equations are used to model the gas flow in the furnace. The discrete Navier-Stokes equations are solved by the SIMPLE(R) pressure-correction method. In these applications, many SIMPLE(R) iterations are necessary to obtain an accurate solution. In this paper, Krylov accelerated versions are proposed: GCR-SIMPLE(R). The properties of these methods are investigated for a simple two-dimensional flow. Thereafter, the efficiencies of the methods are compared for three-dimensional flows in industrial glass-melting furnaces. Copyright

  8. Nonlinear Krylov acceleration applied to a discrete ordinates formulation of the k-eigenvalue problem

    NASA Astrophysics Data System (ADS)

    Calef, Matthew T.; Fichtl, Erin D.; Warsa, James S.; Berndt, Markus; Carlson, Neil N.

    2013-04-01

    We compare a variant of Anderson Mixing with the Jacobian-Free Newton-Krylov and Broyden methods applied to an instance of the k-eigenvalue formulation of the linear Boltzmann transport equation. We present evidence that one variant of Anderson Mixing finds solutions in the fewest number of iterations. We examine and strengthen theoretical results of Anderson Mixing applied to linear problems.

  9. Synthetic sea water - An improved stress corrosion test medium for aluminum alloys

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1973-01-01

    A major problem in evaluating the stress corrosion cracking resistance of aluminum alloys by alternate immersion in 3.5 percent salt (NaCl) water is excessive pitting corrosion. Several methods were examined to eliminate this problem and to find an improved accelerated test medium. These included the addition of chromate inhibitors, surface treatment of specimens, and immersion in synthetic sea water. The results indicate that alternate immersion in synthetic sea water is a very promising stress corrosion test medium. Neither chromate inhibitors nor surface treatment (anodize and alodine) of the aluminum specimens improved the performance of alternate immersion in 3.5 percent salt water sufficiently to be classified as an effective stress corrosion test method.

  10. Solving the Accelerator-Condenser Coupling Problem in a Nanosecond Dynamic Transmission Electron Microscope

    SciTech Connect

    Reed, B W; LaGrange, T; Shuttlesworth, R M; Gibson, D J; Campbell, G H; Browning, N D

    2009-12-29

    We describe a modification to a transmission electron microscope (TEM) that allows it to briefly (using a pulsed-laser-driven photocathode) operate at currents in excess of 10 mA while keeping the effects of condenser lens aberrations to a minimum. This modification allows real-space imaging of material microstructure with a resolution of order 10 nm over regions several {micro}m across with an exposure time of 15 ns. This is more than 6 orders of magnitude faster than typical video-rate TEM imaging. The key is the addition of a weak magnetic lens to couple the large-diameter high-current beam exiting the accelerator into the acceptance aperture of a conventional TEM condenser lens system. We show that the performance of the system is essentially consistent with models derived from ray tracing and finite element simulations. The instrument can also be operated as a conventional TEM by using the electron gun in a thermionic mode. The modification enables very high electron current densities in {micro}m-sized areas and could also be used in a non-pulsed system for high-throughput imaging and analytical TEM.

  11. Solving the accelerator-condenser coupling problem in a nanosecond dynamic transmission electron microscope.

    PubMed

    Reed, B W; LaGrange, T; Shuttlesworth, R M; Gibson, D J; Campbell, G H; Browning, N D

    2010-05-01

    We describe a modification to a transmission electron microscope (TEM) that allows it to briefly (using a pulsed-laser-driven photocathode) operate at currents in excess of 10 mA while keeping the effects of condenser lens aberrations to a minimum. This modification allows real-space imaging of material microstructure with a resolution of order 10 nm over regions several microm across with an exposure time of 15 ns. This is more than six orders of magnitude faster than typical video-rate TEM imaging. The key is the addition of a weak magnetic lens to couple the large-diameter high-current beam exiting the accelerator into the acceptance aperture of a conventional TEM condenser lens system. We show that the performance of the system is essentially consistent with models derived from ray tracing and finite element simulations. The instrument can also be operated as a conventional TEM by using the electron gun in a thermionic mode. The modification enables very high electron current densities in microm-sized areas and could also be used in a nonpulsed system for high-throughput imaging and analytical TEM. PMID:20515144

  12. BWR steel containment corrosion

    SciTech Connect

    Tan, C.P.; Bagchi, G.

    1996-04-01

    The report describes regulatory actions taken after corrosion was discovered in the drywell at the Oyster Creek Plant and in the torus at the Nine Mile Point 1 Plant. The report describes the causes of corrosion, requirements for monitoring corrosion, and measures to mitigate the corrosive environment for the two plants. The report describes the issuances of generic letters and information notices either to collect information to determine whether the problem is generic or to alert the licensees of similar plants about the existence of such a problem. Implementation of measures to enhance the containment performance under severe accident conditions is discussed. A study by Brookhaven National Laboratory (BNL) of the performance of a degraded containment under severe accident conditions is summarized. The details of the BNL study are in the appendix to the report.

  13. pH Sensitive Microcapsules for Delivery of Corrosion Inhibitors

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2006-01-01

    A considerable number of corrosion problems can be solved by coatings. However, even the best protective coatings can fail by allowing the slow diffusion of oxygen and moisture to the metal surface. Corrosion accelerates when a coating delaminates. Often, the problems start when microscopic nicks or pits on the surface develop during manufacturing or through wear and tear. This problem can be solved by the incorporation of a self-healing function into the coating. Several new concepts are currently under development to incorporate this function into a coating. Conductive polymers, nanoparticles, and microcapsules are used to release corrosion-inhibiting ions at a defect site. The objective of this investigation is to develop a smart coating for the early detection and inhibition of corrosion. The dual function of this new smart coating system is performed by pH-triggered release microcapsules. The microcapsules can be used to deliver healing agents to terminate the corrosion process at its early stage or as corrosion indicators by releasing dyes at the localized corrosion sites. The dyes can be color dyes or fluorescent dyes, with or without pH sensitivity. Microcapsules were formed through the interfacial polymerization process. The average size of the microcapsules can be adjusted from 1 to 100 micron by adjusting the emulsion formula and the microcapsule forming conditions. A typical microcapsule size is around 10 microns with a narrow size distribution. The pH sensitivity of the microcapsule can also be controlled by adjusting the emulsion formula and the polymerization reaction time. Both corrosion indicator (pH indicator) and corrosion inhibitor containing microcapsules were formed and incorporated into paint systems. Test panels of selected steels and aluminum alloys were painted using these paints. Testing of compatibility between the microcapsule system and different paint systems are in progress. Initial experiments with the microcapsule containing paint

  14. A QR accelerated volume-to-surface boundary condition for finite element solution of eddy current problems

    SciTech Connect

    White, D; Fasenfest, B; Rieben, R; Stowell, M

    2006-09-08

    We are concerned with the solution of time-dependent electromagnetic eddy current problems using a finite element formulation on three-dimensional unstructured meshes. We allow for multiple conducting regions, and our goal is to develop an efficient computational method that does not require a computational mesh of the air/vacuum regions. This requires a sophisticated global boundary condition specifying the total fields on the conductor boundaries. We propose a Biot-Savart law based volume-to-surface boundary condition to meet this requirement. This Biot-Savart approach is demonstrated to be very accurate. In addition, this approach can be accelerated via a low-rank QR approximation of the discretized Biot-Savart law.

  15. Corrosion cracking

    SciTech Connect

    Goel, V.S.

    1986-01-01

    Various papers on corrosion cracking are presented. The topics addressed include: unique case studies on hydrogen embrittlement failures in components used in aeronautical industry; analysis of subcritical cracking in a Ti-5Al-2.5Sn liquid hydrogen control valve; corrosion fatigue and stress corrosion cracking of 7475-T7351 aluminum alloy; effects of salt water environment and loading frequency on crack initiation in 7075-T7651 aluminum alloy and Ti-6Al-4V; stress corrosion cracking of 4340 steel in aircraft ignition starter residues. Also discussed are: stress corrosion cracking of a titanium alloy in a hydrogen-free environment; automation in corrosion fatigue crack growth rate measurements; the breaking load method, a new approach for assessing resistance to growth of early stage stress corrosion cracks; stress corrosion cracking properties of 2090 Al-Li alloy; repair welding of cracked free machining Invar 36; radial bore cracks in rotating disks.

  16. Stress corrosion cracking evaluation of precipitation-hardening stainless steel

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1970-01-01

    Accelerated test program results show which precipitation hardening stainless steels are resistant to stress corrosion cracking. In certain cases stress corrosion susceptibility was found to be associated with the process procedure.

  17. Corrosion resistance of stainless steels

    SciTech Connect

    Dillon, C.P.

    1995-12-31

    This book reviews the mechanisms and forms of corrosion and examines the corrosion of stainless steels and similar chromium-bearing nickel containing higher alloys, detailing various corrosive environments including atmospheric and fire-side corrosion, corrosion by water and soil, and corrosion caused by particular industrial processes. It provides information on specific groups and grades of stainless steels; summarizes typical applications for specific stainless alloys; describes common corrosion problems associated with stainless steels; presents the acceptable isocorrosion parameters of concentration and temperature for over 250 chemicals for which stainless steels are the preferred materials of construction; discusses product forms and their availability; elucidates fabrication, welding, and joining techniques; and covers the effects of pickling and passivation.

  18. Evaluating Heat Pipe Performance in 1/6 g Acceleration: Problems and Prospects

    NASA Technical Reports Server (NTRS)

    Jaworske, Donald A.; McCollum, Timothy A.; Gibson, Marc A.; Sanzi, James L.; Sechkar, Edward A.

    2011-01-01

    Heat pipes composed of titanium and water are being considered for use in the heat rejection system of a fission power system option for lunar exploration. Placed vertically on the lunar surface, the heat pipes would operate as thermosyphons in the 1/6 g environment. The design of thermosyphons for such an application is determined, in part, by the flooding limit. Flooding is composed of two components, the thickness of the fluid film on the walls of the thermosyphon and the interaction of the fluid flow with the concurrent vapor counter flow. Both the fluid thickness contribution and interfacial shear contribution are inversely proportional to gravity. Hence, evaluating the performance of a thermosyphon in a 1 g environment on Earth may inadvertently lead to overestimating the performance of the same thermosyphon as experienced in the 1/6 g environment on the moon. Several concepts of varying complexity have been proposed for evaluating thermosyphon performance in reduced gravity, ranging from tilting the thermosyphons on Earth based on a cosine function, to flying heat pipes on a low-g aircraft. This paper summarizes the problems and prospects for evaluating thermosyphon performance in 1/6 g.

  19. Reduced quality and accelerated follicle loss with female reproductive aging - does decline in theca dehydroepiandrosterone (DHEA) underlie the problem?

    PubMed

    Ford, Judith H

    2013-01-01

    Infertility, spontaneous abortion and conception of trisomic offspring increase exponentially with age in mammals but in women there is an apparent acceleration in the rate from about age 37. The problems mostly commonly occur when the ovarian pool of follicles is depleted to a critical level with age but are also found in low follicular reserve of other etiologies. Since recent clinical studies have indicated that dehydroepiandrosterone (DHEA) supplementation may reverse the problem of oocyte quality, this review of the literature was undertaken in an attempt to find an explanation of why this is effective? In affected ovaries, oxygenation of follicular fluid is low, ultrastructural disturbances especially of mitochondria, occur in granulosa cells and oocytes, and considerable disturbances of meiosis occur. There is, however, no evidence to date that primordial follicles are compromised. In females with normal fertility, pre-antral ovarian theca cells respond to stimulation by inhibin B to provide androgen-based support for the developing follicle. With depletion of follicle numbers, inhibin B is reduced with consequent reduction in theca DHEA. Theca cells are the sole ovarian site of synthesis of DHEA, which is both a precursor of androstenedione and an essential ligand for peroxisome proliferator-activated receptor alpha (PPARα), the key promoter of genes affecting fatty acid metabolism and fat transport and genes critical to mitochondrial function. As well as inducing a plethora of deleterious changes in follicular cytoplasmic structure and function, the omega 9 palmitate/oleate ratio is increased by lowered activity of PPARα. This provides conditions for increased ceramide synthesis and follicular loss through ceramide-induced apoptosis is accelerated. In humans critical theca DHEA synthesis occurs at about 70 days prior to ovulation thus effective supplementation needs to be undertaken about four months prior to intended conception; timing which is also

  20. Effects of Solution Hydrodynamics on Corrosion Inhibition of Steel by Citric Acid in Cooling Water

    NASA Astrophysics Data System (ADS)

    Ashassi-Sorkhabi, H.; Asghari, E.; Mohammadi, M.

    2014-08-01

    Corrosion is a major problem in cooling water systems, which is often controlled using corrosion inhibitors. Solution hydrodynamics is one of the factors affecting corrosion inhibition of metals in these systems. The present work focuses on the study of the combined effects of citric acid concentration (as a green corrosion inhibitor) and fluid flow on corrosion of steel in simulated cooling water. Electrochemical techniques including Tafel polarization and electrochemical impedance spectroscopy were used for corrosion studies. Laminar flow was simulated using a rotating disk electrode. The effects of solution hydrodynamics on inhibition performance of citric acid were discussed. The citric acid showed low inhibition performance in quiescent solution; however, when the electrode rotated at 200 rpm, inhibition efficiency increased remarkably. It was attributed mainly to the acceleration of inhibitor mass transport toward metal surface. The efficiencies were then decreased at higher rotation speeds due to enhanced wall shear stresses on metal surface and separation of adsorbed inhibitor molecules. This article is first part of authors' attempts in designing green inhibitor formulations for industrial cooling water. Citric acid showed acceptable corrosion inhibition in low rotation rates; thus, it can be used as a green additive to the corrosion inhibitor formulations.

  1. Chemical corrosion potential in boilers

    SciTech Connect

    Bairr, D.L.; McDonough, C.J.

    1998-12-31

    Misuse or abuse of chelants has long been recognized as a potential corrosion problem in boilers. In recent years all polymer chemical treatment programs have been introduced and although they are much more benign even all polymer programs must be properly designed and controlled. Under extreme conditions a similar corrosion potential exists. This paper discusses the potential for chelant or polymer corrosion in boilers and the proper safeguards. Case histories are presented.

  2. Microencapsulation of Corrosion Indicators for Smart Coatings

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.; Calle, Luz M.; Hanna,Joshua S.; Rawlins, James W.

    2011-01-01

    A multifunctional smart coating for the autonomous detection, indication, and control of corrosion is been developed based on microencapsulation technology. This paper summarizes the development, optimization, and testing of microcapsules specifically designed for early detection and indication of corrosion when incorporated into a smart coating. Results from experiments designed to test the ability of the microcapsules to detect and indicate corrosion, when blended into several paint systems, show that these experimental coatings generate a color change, indicative of spot specific corrosion events, that can be observed with the naked eye within hours rather than the hundreds of hours or months typical of the standard accelerated corrosion test protocols.. Key words: smart coating, corrosion detection, microencapsulation, microcapsule, pH-sensitive microcapsule, corrosion indicator, corrosion sensing paint

  3. Corrosion `98: 53. annual conference and exposition, proceedings

    SciTech Connect

    1998-12-31

    This conference was divided into the following sections: Corrosion in Gas Treating; Problems and Solutions in Commercial Building Water Systems; Green Corrosion/Scale Inhibitors; Atmospheric Corrosion; AIRPOL Update/98; Rubber Lining--Answers to Many Problems; Interference Problems; Environmental Assisted Cracking: Fundamental Research and Industrial Applications; Corrosion in Nuclear Systems; New Developments in Scale and Deposit Control; Corrosion and Corrosion Protection in the Transportation Industries; What`s All the Noise About--Electrochemical That Is; Refining Industry Corrosion; Corrosion Problems in Military Hardware: Case Histories, Fixes and Lessons Learned; Cathodic Protection Test Methods and Instrumentation for Underground and On-grade Pipelines and Tanks; Recent Developments in Volatile Corrosion Inhibitors; Corrosion in Supercritical Fluids; Microbiologically Influenced Corrosion; Advances in Understanding and Controlling CO{sub 2} Corrosion; Managing Corrosion with Plastics; Material Developments for Use in Exploration and Production Environments; Corrosion in Cold Regions; The Effect of Downsizing and Outsourcing on Cooling System Monitoring and Control Practices; New Developments in Mechanical and Chemical Industrial Cleaning; Mineral Scale Deposit Control in Oilfield Related Operations; Biocides in Cooling Water; Corrosion and Corrosion Control of Reinforced Concrete Structures; Materials Performance for Fossil Energy Conversion Systems; Marine corrosion; Thermal Spray--Coating and Corrosion Control; Flow Effects on Corrosion in Oil and Gas Production; Corrosion Measurement Technologies; Internal Pipeline Monitoring--Corrosion Monitoring, Intelligent Pigging and Leak Detection; Cathodic Protection in Natural Waters; Corrosion in Radioactive Liquid Waste Systems; On-line Hydrogen Permeation Monitoring Equipment and Techniques, State of the Art; Water Reuse and Recovery; Performance of Materials in High Temperature Environments; Advances in Motor

  4. INTERNAL CORROSION AND DEPOSITION CONTROL

    EPA Science Inventory

    Corrosion is one of the most important problems in the drinking water industry. It can affect public health, public acceptance of a water supply, and the cost of providing safe water. Deterioration of materials resulting from corrosion can necessitate huge yearly expenditures o...

  5. Corrosion beneath disbonded pipeline coatings

    SciTech Connect

    Beavers, J.A.; Thompson, N.G.

    1997-04-01

    The relationship between coatings, cathodic protection (CP), and external corrosion of underground pipelines is described. Historically, this problem has been addressed by focusing on the corrosion and CP processes associated with holidays, e.g., coating disbondment and CP current flow within the disbonded region. These issues and those associated with disbonded areas distant from holidays are also discussed.

  6. Aircraft corrosion surveillance in the military

    SciTech Connect

    Tullmin, M.; Roberge, P.R.; Little, M.A.

    1997-12-01

    In the Canadian Forces, as for other operators of aging aircraft, the need has arisen to utilize new tools for managing corrosion problems more cost effectively. Corrosion surveillance methodologies are focused on the reduction of unnecessary inspections and on optimizing certain maintenance and inspection schedules. To accomplish the former, on-going development of on-board corrosion sensors is required, with the ultimate goal of establishing truly smart structures. For the optimization of these schedules, a link between the corrosivity of the operating environment and these schedules is needed. Information on atmospheric corrosivity of the operating environment and these schedules is needed. Information on atmospheric corrosivity at a marine base is sought in terms of an overall corrosivity map of the base, real-time atmospheric corrosivity measurements in the external atmosphere and air quality monitoring in air-conditioned hangars. Corrosion surveillance information should be integrated with complementary data and information to enhance its value and impact.

  7. Corrosion beneath disbonded coatings: A review

    SciTech Connect

    Beavers, J.A.; Thompson, N.G.

    1996-12-01

    This paper describes the relationship between coatings, cathodic protection (CP), and external corrosion of underground pipelines. Historically, this problem has been addressed by focusing on the corrosion and CP processes associated with holidays, e.g., coating disbandment and CP current flow within the disbanded region. This paper addresses these issues but also considers corrosion associated with disbanded areas that are distant from holidays.

  8. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

    There has been invented a chemically bonded phosphate corrosion protection material and process for application of the corrosion protection material for corrosion prevention. A slurry of iron oxide and phosphoric acid is used to contact a warm surface of iron, steel or other metal to be treated. In the presence of ferrous ions from the iron, steel or other metal, the slurry reacts to form iron phosphates which form grains chemically bonded onto the surface of the steel.

  9. [Microbial corrosion of dental alloy].

    PubMed

    Li, Lele; Liu, Li

    2004-10-01

    There is a very complicated electrolytical environment in oral cavity with plenty of microorganisms existing there. Various forms of corrosion would develop when metallic prosthesis functions in mouth. One important corrosive form is microbial corrosion. The metabolic products, including organic acid and inorganic acid, will affect the pH of the surface or interface of metallic prosthesis and make a change in composition of the medium, thus influencing the electron-chemical reaction and promoting the development of corrosion. The problem of develpoment of microbial corrosion on dental alloy in the oral environment lies in the primary condition that the bacteria adhere to the surface of alloy and form a relatively independent environment that promotes corrosion. PMID:15553877

  10. Estimation of corrosion damage in steel reinforced mortar using waveguides

    NASA Astrophysics Data System (ADS)

    Reis, Henrique; Ervin, Benjamin L.; Kuchma, Daniel A.; Bernhard, Jennifer

    2005-05-01

    Corrosion of reinforced concrete is a chronic infrastructure problem, particularly in areas with deicing salt and marine exposure. To maintain structural integrity, a testing method is needed to identify areas of corroding reinforcement. For purposes of rehabilitation, the method must also be able to evaluate the degree, rate and location of damage. Towards the development of a wireless embedded sensor system to monitor and assess corrosion damage in reinforced concrete, reinforced mortar specimens were manufactured with seeded defects to simulate corrosion damage. Taking advantage of waveguide effects of the reinforcing bars, these specimens were then tested using an ultrasonic approach. Using the same ultrasonic approach, specimens without seeded defects were also monitored during accelerated corrosion tests. Both the ultrasonic sending and the receiving transducers were mounted on the steel rebar. Advantage was taken of the lower frequency (<250 kHz) fundamental flexural propagation mode because of its relatively large displacements at the interface between the reinforcing steel and the surrounding concrete. Waveform energy (indicative of attenuation) is presented and discussed in terms of corrosion damage. Current results indicate that the loss of bond strength between the reinforcing steel and the surrounding concrete can be detected and evaluated.

  11. Mechanism of hot corrosion of IN-738

    NASA Technical Reports Server (NTRS)

    Meier, G. H.

    1982-01-01

    The Na2SO4 - induced hot corrosion of IN-738 in the temperature range 900 C to 1000 C is characterized by an initiation stage during which the corrosion rate is slow followed by a propagation stage during which the corrosion rate is markedly accelerated. In the second stage, corrosion is accelerated due essentially to a sulfidation/oxidation mechanism; in the third stage, the rate becomes catastrophic due to acid fluxing induced by an accumulation of refractory metal oxides (particularly MoO3) in the Na2SO4. The sequential stages in the corrosion process are described and a mechanism proposed. The influence of alloy microstructure on the corrosion mechanism is also discussed.

  12. Terahertz NDE for Under Paint Corrosion Detection and Evaluation

    NASA Technical Reports Server (NTRS)

    Anastasi, Robert F.; Madaras, Eric I.

    2005-01-01

    Corrosion under paint is not visible until it has caused paint to blister, crack, or chip. If corrosion is allowed to continue then structural problems may develop. Identifying corrosion before it becomes visible would minimize repairs and costs and potential structural problems. Terahertz NDE imaging under paint for corrosion is being examined as a method to inspect for corrosion by examining the terahertz response to paint thickness and to surface roughness.

  13. Corrosion in NiCd cells

    NASA Technical Reports Server (NTRS)

    Badcock, C.; Galligan, J.

    1981-01-01

    Corrosion in the terminals of nickel cadmium cells was investigated. Corrosion, crevice type corrosion, at the interface between the stainless steel material, the nickel material, and the braze was examined. It was concluded that in the welded areas there was no problem. There was corrosion of the crevice type in the brazed areas and some pitting was evident between the braze and the base material.

  14. Fireside Corrosion

    SciTech Connect

    Holcomb, Gordon

    2011-07-14

    Oxy-fuel fireside research goals are: (1) determine the effect of oxyfuel combustion on fireside corrosion - flue gas recycle choice, staged combustion ramifications; and (2) develop methods to use chromia solubility in ash as an ash corrosivity measurement - synthetic ashes at first, then boiler and burner rig ashes.

  15. Corrosion Engineering.

    ERIC Educational Resources Information Center

    White, Charles V.

    A description is provided for a Corrosion and Corrosion Control course offered in the Continuing Engineering Education Program at the General Motors Institute (GMI). GMI is a small cooperative engineering school of approximately 2,000 students who alternate between six-week periods of academic study and six weeks of related work experience in…

  16. Principles of development and specific features relating to practical application of software for solving problems connected with erosion-corrosion of metal in power engineering

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Shipkov, A. A.

    2011-02-01

    Principles used in the development of modern computation codes for calculating erosion-corrosion of power equipment are considered. Specific features of their practical applications aimed at preventing, revealing, and eliminating erosion-corrosion thinning of the metal of elements used in the units of power stations are analyzed. Results obtained from using the domestically developed computation code RAMEK for operating power units are presented and prospects for implementing it in designing new power units of nuclear power stations are determined.

  17. Elephant butte powerplant investigation of permanent magnet generator corrosion and bearing failures. Project notes 8450-97-07. Technical memo

    SciTech Connect

    Price, P.; Atwater, P.

    1997-04-01

    This investigation and report were initiated in response to a request to determine causes for excessive corrosion and premature bearing failures on the Woodward Permanent Magnet Generator (PMG) on the three main generating units at Elephant Butte. All three main generating units were rewound using epoxy-type insulating materials between 1989 and 1991. Plant personnel reported that corrosion and failure rates seemed to accelerate after the new stator windings were installed. This report documents field testing conducted the week of March 10, 1997, to determine if stray electrical currents/voltages were causing the problems. Electrical field test results indicate that accelerated PMG bearing failure and corrosion were not caused by stray voltages or current. Tests were conducted on the main shaft in the turbine pit and on the PMG shaft and housing located atop the exciter shaft.

  18. Investigation of corrosion experienced in a spray calciner/ceramic melter vitrification system

    SciTech Connect

    Dierks, R.D.; Mellinger, G.B.; Miller, F.A.; Nelson, T.A.; Bjorklund, W.J.

    1980-08-01

    After periodic testing of a large-scale spray calciner/ceramic melter vitrification system over a 2-yr period, sufficient corrosion was noted on various parts of the vitrification system to warrant its disassembly and inspection. A majority of the 316 SS sintered metal filters on the spray calciner were damaged by chemical corrosion and/or high temperature oxidation. Inconel-601 portions of the melter lid were attacked by chlorides and sulfates which volatilized from the molten glass. The refractory blocks, making up the walls of the melter, were attacked by the waste glass. This attack was occurring when operating temperatures were >1200/sup 0/C. The melter floor was protected by a sludge layer and showed no corrosion. Corrosion to the Inconel-690 electrodes was minimal, and no corrosion was noted in the offgas treatment system downstream of the sintered metal filters. It is believed that most of the melter corrosion occurred during one specific operating period when the melter was operated at high temperatures in an attempt to overcome glass foaming behavior. These high temperatures resulted in a significant release of volatile elements from the molten glass, and also created a situation where the glass was very fluid and convective, which increased the corrosion rate of the refractories. Specific corrosion to the calciner components cannot be proven to have occurred during a specific time period, but the mechanisms of attack were all accelerated under the high-temperature conditions that were experienced with the melter. A review of the materials of construction has been made, and it is concluded that with controlled operating conditions and better protection of some materials of construction corrosion of these systems will not cause problems. Other melter systems operating under similar strenuous conditions have shown a service life of 3 yr.

  19. Atmospheric corrosion of metals in industrial city environment

    PubMed Central

    Kusmierek, Elzbieta; Chrzescijanska, Ewa

    2015-01-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust. PMID:26217736

  20. Atmospheric corrosion of metals in industrial city environment.

    PubMed

    Kusmierek, Elzbieta; Chrzescijanska, Ewa

    2015-06-01

    Atmospheric corrosion is a significant problem given destruction of various materials, especially metals. The corrosion investigation in the industrial city environment was carried out during one year exposure. Corrosion potential was determined using the potentiometric method. The highest effect of corrosion processes was observed during the winter season due to increased air pollution. Corrosion of samples pre-treated in tannic acid before the exposure was more difficult compared with the samples without pretreatment. The corrosion products determined with the SEM/EDS method prove that the most corrosive pollutants present in the industrial city air are SO2, CO2, chlorides and dust. PMID:26217736

  1. Accelerated Weathering of Waste Glass at 90°C with the Pressurized Unsaturated Flow (PUF) Apparatus: Implications for Predicting Glass Corrosion with a Reactive Transport Model

    SciTech Connect

    Pierce, Eric M.; Bacon, Diana H.

    2009-09-21

    The interest in the long-term durability of waste glass stems from the need to predict radionuclide release rates from the corroding glass over geologic time-scales. Several long-term test methods have been developed to accelerate the glass-water reaction [drip test, vapor hydration test, product consistency test-B, and pressurized unsaturated flow (PUF)]. Currently, the PUF test is the only method that can mimic the unsaturated hydraulic properties expected in a subsurface disposal facility and simultaneously monitor the glass-water reaction. PUF tests are being conducted to accelerate the weathering of glass and validate the model parameters being used to predict long-term glass behavior. One dimensional reactive chemical transport simulations of glass dissolution and secondary phase formation during a 1.5-year long PUF experiment was conducted with the subsurface transport over reactive multi-phases (STORM) code. Results show that parameterization of the computer model by combining direct laboratory measurements and thermodynamic data provides an integrated approach to predicting glass behavior over geologic-time scales.

  2. The dual role of microbes in corrosion

    PubMed Central

    Kip, Nardy; van Veen, Johannes A

    2015-01-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion. PMID:25259571

  3. The dual role of microbes in corrosion.

    PubMed

    Kip, Nardy; van Veen, Johannes A

    2015-03-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced products are under increasing pressure of stringent environmental regulations. Furthermore, they are rather inefficient. Therefore, there is an urgent need for environmentally friendly and sustainable corrosion control strategies. The mechanisms of microbially influenced corrosion and microbially influenced corrosion inhibition are not completely understood, because they cannot be linked to a single biochemical reaction or specific microbial species or groups. Corrosion is influenced by the complex processes of different microorganisms performing different electrochemical reactions and secreting proteins and metabolites that can have secondary effects. Information on the identity and role of microbial communities that are related to corrosion and corrosion inhibition in different materials and in different environments is scarce. As some microorganisms are able to both cause and inhibit corrosion, we pay particular interest to their potential role as corrosion-controlling agents. We show interesting interfaces in which scientists from different disciplines such as microbiology, engineering and art conservation can collaborate to find solutions to the problems caused by corrosion. PMID:25259571

  4. Effect of hot corrosion on the creep properties of types 321 and 347 stainless steels

    SciTech Connect

    Gonzalez-Rodriguez, J.G.; Luna-Ramirez, A.; Martinez-Villafane, A.

    1999-02-01

    Problems caused by hot corrosion and creep damage on superheater and reheater tubes of power plants using heavy oil as fuel inhibit the continuous service of the boilers and shorten their design lives. The acceleration of hot corrosion attack of boilers is caused by the presence of fuel ash deposits containing V, Na, and S, in the form of Na{sub 2}SO{sub 4} and V{sub 2}O{sub 5}, which form low melting point phases. In addition to this, the tubes are exposed to the action of both high stresses and high temperatures, producing a continuous plastic deformation of the tube walls called creep damage. Creep rupture tests were carried out in the temperature range 620 to 670 C in static air in the presence of corrosive environments using 321H and 347H type stainless steels used in superheater and reheater tubes under hot corrosion and creep environments. The corrosive environment includes synthetic Na{sub 2}SO{sub 4}, V{sub 2}O{sub 5}, and the mixture 80% V{sub 2}O{sub 5}-20%Na{sub 2}So{sub 4}. Also, the role of the different elements present in the environments on corrosion was investigated using electronic microscopy and x-ray diffraction techniques.

  5. Modeling and identification of uniform corrosion damage on a thin plate using a Bayesian framework

    NASA Astrophysics Data System (ADS)

    Moore, Edward Z.; Murphy, Kevin D.; Rey, Elizabeth G.; Nichols, Jonathan M.

    2015-03-01

    Corrosion remains one of the primary mechanisms of structural degradation facing the civil and commercial infrastructure. In this study we consider the problem of estimating the degree of corrosion in a plate structure using only the structure's vibrational response to impact excitation. Specifically, a thin aluminum plate was twice placed in an accelerated corrosion environment resulting in varying levels of corrosion damage. At each damage level, the impulse response at three different locations was simultaneously measured with resistive strain gauges. From this data, a Ritz model with Timoshenko beam basis functions was used in a Bayesian framework to estimate the average plate thickness. The approach is first illustrated on a numerical model of the plate, and then applied to the experimental structural response. While the approach is able to accurately estimate the thickness of the "healthy" plate, the quality of the estimates degrades as the corrosion begins to alter the thickness in localized regions of the plate. This is reflected in the thickness estimates which show increasing variance with the degree of corrosion.

  6. Effect of hot corrosion on the creep properties of types 321 and 347 stainless steels

    NASA Astrophysics Data System (ADS)

    González-Rodríguez, J. G.; Luna-Ramírez, A.; Martínez-Villafañe, A.

    1999-02-01

    Problems caused by hot corrosion and creep damage on superheater and reheater tubes of power plants using heavy oil as fuel inhibit the continuous service of the boilers and shorten their design lives. The acceleration of hot corrosion attack of boilers is caused by the presence of fuel ash deposits containing V, Na, and S, in the form of Na2SO4 and V2O5, which form low melting point phases. In addition to this, the tubes are exposed to the action of both high stresses and high temperatures, producing a continuous plastic deformation of the tube walls called creep damage. Creep rupture tests were carried out in the temperature range 620 to 670 °C in static air in the presence of corrosive environments using 321H and 347H type stainless steels used in superheater and reheater tubes under hot corrosion and creep environments. The corrosive environment includes synthetic Na2SO4, V2O5, and the mixture 80% V2O5-20%Na2SO4. Also, the role of the different elements present in the environments on corrosion was investigated using electronic microscopy and x-ray diffraction techniques.

  7. Biofouling and microbial corrosion problem in the thermo-fluid heat exchanger and cooling water system of a nuclear test reactor.

    PubMed

    Rao, T S; Kora, Aruna Jyothi; Chandramohan, P; Panigrahi, B S; Narasimhan, S V

    2009-10-01

    This article discusses aspects of biofouling and corrosion in the thermo-fluid heat exchanger (TFHX) and in the cooling water system of a nuclear test reactor. During inspection, it was observed that >90% of the TFHX tube bundle was clogged with thick fouling deposits. Both X-ray diffraction and Mossbauer analyses of the fouling deposit demonstrated iron corrosion products. The exterior of the tubercle showed the presence of a calcium and magnesium carbonate mixture along with iron oxides. Raman spectroscopy analysis confirmed the presence of calcium carbonate scale in the calcite phase. The interior of the tubercle contained significant iron sulphide, magnetite and iron-oxy-hydroxide. A microbiological assay showed a considerable population of iron oxidizing bacteria and sulphate reducing bacteria (10(5) to 10(6) cfu g(-1) of deposit). As the temperature of the TFHX is in the range of 45-50 degrees C, the microbiota isolated/assayed from the fouling deposit are designated as thermo-tolerant bacteria. The mean corrosion rate of the CS coupons exposed online was approximately 2.0 mpy and the microbial counts of various corrosion causing bacteria were in the range 10(3) to 10(5) cfu ml(-1) in the cooling water and 10(6) to 10(8) cfu ml(-1) in the biofilm. PMID:20183117

  8. Liquefaction corrosion

    SciTech Connect

    DeVan, J.H.; Keiser, J.R.; Baylor, V.B.

    1980-01-01

    The goal of this program is to provide screening data on the susceptibility to corrosion of commercial base metals and welds that are candidate materials of construction for large coal liquefaction plants. Specimens are exposed in operating environments of liquefaction pilot plants and under controlled laboratory conditions to establish acceptable conditions of stress, temperature, time, and environment for candidate alloys. Chemical analyses have been carried out to identify the corrosion-causing constituents of the liquids. The behavior of potential containment materials is being assessed on the basis of results from both in-plant exposure of test specimens as well as results from laboratory tests at ORNL. One portion of the in-plant tests includes exposing stress corrosion cracking specimens in critical areas of liquefaction plants. The critical areas include the dissolver vessel, the pressure letdown vessels, and the factionation columns. Other in-plant tests consist of exposure of corrosion coupons in areas where general corrosion has been severe. These areas include the fractionation columns used for recovery of process and wash solvents. Laboratory tests are being conducted using selected liquid process streams from the pilot plants to simulate SRC environments. Sample materials include the full range of austenitic stainless steels, most of the Inconel, Incoloy and Hastelloy high-nickel alloys, ferritic stainless steels, and Cr-Mo steels, as well as pure materials such as titanium, aluminum and nickel.

  9. Corrosion and scaling in solar heating systems

    NASA Astrophysics Data System (ADS)

    Foresti, R. J., Jr.

    1981-12-01

    Corrosion, as experienced in solar heating systems, is described in simplistic terms to familiarize designers and installers with potential problems and their solutions. The role of a heat transfer fluid in a solar system is briefly discussed, and the choice of an aqueous solution is justified. The complexities of the multiple chemical and physical reactions are discussed in order that uncertainties of corrosion behavior can be anticipated. Some basic theories of corrosion are described, aggressive environments for some common metals are identified, and the role of corrosion inhibitors is delineated. The similarities of thermal and material characteristics of a solor system and an automotive cooling system are discussed. Based on the many years of experience with corrosion in automotive systems, it is recommended that similar antifreezes and corrosion inhibitors should be used in solar systems. The importance of good solar system design and fabrication is stressed and specific characteristics that affect corrosion are identified.

  10. The 43rd annual corrosion survey

    SciTech Connect

    Not Available

    1992-03-01

    Applying the science of corrosion prevention to energy (petroleums, oil, LNG) pipelines in actual field operating conditions is a vital aspect of safely and efficiently operating a pipeline system. Ignoring corrosion prevention will allow this never-sleeping enemy to steal the strength from steel pipelines, turning them into dangerous junk. Various methods, techniques and technologies are available to the corrosion control department of cross-country pipelines and gas distribution utilities around the world. Every year, billions of dollars on corrosion control, including everything from coatings to cathodic protection facilities to pigging, are spent to keep these energy pipeline systems in peak operational efficiency. This paper reports that for more than 4 decades, this corrosion survey has sought out the opinions of corrosion control experts, asking them what are the problems they face daily and innovative solutions they have tried to help solve these problems.

  11. Microbial problems in connection with storage of jet fuel in rock caverns. Development of a process for purification of corrosive jet fuel). Mikrobiella problem vid bergrumslagring av jetbraensle. Utveckling av process foer rening av korrosivt jetbraensle

    SciTech Connect

    Roffey, R.

    1985-06-01

    The literature concerning desulfurization is summarized. Investigations concerning the use of different compounds in order to purify corrosive jet fuel are described. A process for purification of corrosive jet fuel with 1-5 mg/l elemental sulphur was developed which is based on powdered silver as adsorbent. The capacity for adsorption was determined. On the basis of the data obtained, a scale-up was carried out to a full scale plant. The plant was planned for a capacity of 100 - 300 mT fuel/hour and so that it can be constructed as a mobile unit enabling it to be transported to various storage plants.

  12. Atmospheric Corrosion

    PubMed Central

    Eyring, Henry; Robertson, Blake; Chu, Chih Chien; Andersen, Terrell

    1974-01-01

    A model of electrolytic corrosion is developed. It is shown that electrically conducting channels threading through the oxide layer and connecting anodic and cathodic areas, obey the equation for a reactant being catalyzed by its product. The resulting autocatalytic equation is compared with available experimental data and found to be widely applicable and capable of unifying many experimental observations. PMID:16592135

  13. CORROSION INHIBITION

    DOEpatents

    Cartledge, G.H.

    1958-06-01

    The protection of ferrous metsls from the corrosive action of aqueous solutions is accomplished by the incorporation of small amounts of certain additive agents into the aqueous solutions. The method comprises providing a small concentration of technetium, in the form of pertechnetate ion, dissolved in the solution.

  14. Atmospheric corrosion.

    PubMed

    Eyring, H; Robertson, B; Chu, C C; Andersen, T

    1974-02-01

    A model of electrolytic corrosion is developed. It is shown that electrically conducting channels threading through the oxide layer and connecting anodic and cathodic areas, obey the equation for a reactant being catalyzed by its product. The resulting autocatalytic equation is compared with available experimental data and found to be widely applicable and capable of unifying many experimental observations. PMID:16592135

  15. Quick-hardening problems are eliminated with spray gun modification which mixes resin and accelerator liquids during application

    NASA Technical Reports Server (NTRS)

    Johnson, O. W.

    1964-01-01

    A modified spray gun, with separate containers for resin and additive components, solves the problems of quick hardening and nozzle clogging. At application, separate atomizers spray the liquids in front of the nozzle face where they blend.

  16. Accelerator-based neutron radioscopic systems

    NASA Astrophysics Data System (ADS)

    Berger, Harold; Dance, William E.

    1999-06-01

    There is interest in non-reactor source, thermal neutron inspection systems for applications in aircraft maintenance, explosive devices, investment-cast turbine blades, etc. Accelerator sources, (d-T), RFQ accelerators and cyclotrons as examples, are available for either transportable or fixed neutron inspection systems. Sources are reviewed for neutron output, portability, ease of use and cost, and for use with an electronic neutron imaging camera (image intensifier or scintillator-camera system) to provide a prompt response, neutron inspection system. Particular emphasis is given to the current aircraft inspection problem to detect and characterize corrosion. Systems are analyzed to determine usefulness in providing an on-line inspection technique to detect corrosion in aluminum honeycomb aircraft components, either on-aircraft or in a shop environment. The neutron imaging sensitivity to hydrogenous aluminum corrosion product offers early detection advantages for aircraft corrosion, to levels of aluminum metal loss as small as 25 μm. The practical capability for a continuous scan thermal neutron radioscopic system to inspect up to 500 square feet of component surface per day is used as an evaluation criterion, with the system showing contrast sensitivity of at least 5% and image detail in the order of 4 mm for parts 10 cm thick. Under these practical conditions and 3-shift operation, the source must provide an incident thermal neutron flux of 5.6×104n cm-2 s-1 at an L/D of 30. A stop and go inspection approach, offering improved resolution, would require a source with similar characteristics.

  17. Corrosion Performance of Inconel 625 in High Sulphate Content

    NASA Astrophysics Data System (ADS)

    Ismail, Azzura

    2016-05-01

    Inconel 625 (UNS N06625) is a type of nickel-chromium-molybdenum alloy with excellent corrosion resistance in a wide range of corrosive media, being especially resistant to pitting and crevice corrosion. However, in aggressive environment, Inconel 625 will suffer corrosion attack like other metals. This research compared the corrosion performance of Inconel 625 when exposed to higher sulphate content compared to real seawater. The results reveal that Inconel 625 is excellent in resist the corrosion attack in seawater. However, at increasing temperature, the corrosion resistance of this metal decrease. The performance is same in seawater with high sulphate content at increasing temperature. It can be concluded that sulphate promote perforation on Inconel 625 and become aggressive agents that accelerate the corrosion attack.

  18. Corrosion 99: Proceedings

    SciTech Connect

    1999-11-01

    This conference includes the following; Corrosion in Gas Treating; Advances in Scale and Deposit Control; Uses of Computers for Improved Corrosion Control; Erosion-Corrosion in Steam Generating Systems; Electrochemical Noise Measurements for Corrosion Evaluations; Materials Performance in Fossil Fuel Combustion and Conversion Systems; Corrosion in Super Critical Processes; Cathodic Protection of External Surfaces for Underground and Aboveground Storage Tanks; Microbiologically Influenced Corrosion; Advances in Materials for Oilfield Applications; Refining Industry Corrosion; Green Corrosion/Scale Inhibition Technologies; Managing Corrosion With Plastics; Corrosion Measurement Technology; Marine Corrosion; Improved Understanding and Mitigation of CO{sub 2} Corrosion; Thermal Spray Coatings for Corrosion Protection; Volatile Corrosion Inhibitors; Corrosion Testing in Concrete; Stress Corrosion Cracking: Field Laboratory Correlations; Materials Performance in Incineration and Waste Fuel Combustion Environments; Water Reuse in Industry; Corrosion Control and Prevention of Military and Aerospace Equipment; Corrosion in Nuclear Systems; Latest Developments in Aboveground Storage Tanks Corrosion Control, Monitoring and Evaluation Technology; Internal In-line Inspection of Pipelines and Evaluation of Results; New Developments in Cathodic Protection of Reinforcing Steels in Concrete; Cathodic Protection in Natural Waters; Corrosion in the Pulp and Paper Industry; Advanced Materials for High Temperature Service in Chemical Process Industry; Advances in Cooling Water Treatment; Materials, Fabrication, and Inspection Guidelines for Wet H{sub 2}S Service; Environmental Wear of Nonmetallics in Oilfield Service; and Corrosion and Scale Control in Low Pressure Boiler and Steam Systems in Buildings. Separate abstracts were prepared for most of the papers.

  19. Corrosion 99: Proceedings

    SciTech Connect

    Not Available

    1999-01-01

    This conference includes the following; Corrosion in Gas Treating; Advances in Scale and Deposit Control; Uses of Computers for Improved Corrosion Control; Erosion-Corrosion in Steam Generating Systems; Electrochemical Noise Measurements for Corrosion Evaluations; Materials Performance in Fossil Fuel Combustion and Conversion Systems; Corrosion in Super Critical Processes; Cathodic Protection of External Surfaces for Underground and Aboveground Storage Tanks; Microbiologically Influenced Corrosion; Advances in Materials for Oilfield Applications; Refining Industry Corrosion; Green Corrosion/Scale Inhibition Technologies; Managing Corrosion With Plastics; Corrosion Measurement Technology; Marine Corrosion; Improved Understanding and Mitigation of CO[sub 2] Corrosion; Thermal Spray Coatings for Corrosion Protection; Volatile Corrosion Inhibitors; Corrosion Testing in Concrete; Stress Corrosion Cracking: Field Laboratory Correlations; Materials Performance in Incineration and Waste Fuel Combustion Environments; Water Reuse in Industry; Corrosion Control and Prevention of Military and Aerospace Equipment; Corrosion in Nuclear Systems; Latest Developments in Aboveground Storage Tanks Corrosion Control, Monitoring and Evaluation Technology; Internal In-line Inspection of Pipelines and Evaluation of Results; New Developments in Cathodic Protection of Reinforcing Steels in Concrete; Cathodic Protection in Natural Waters; Corrosion in the Pulp and Paper Industry; Advanced Materials for High Temperature Service in Chemical Process Industry; Advances in Cooling Water Treatment; Materials, Fabrication, and Inspection Guidelines for Wet H[sub 2]S Service; Environmental Wear of Nonmetallics in Oilfield Service; and Corrosion and Scale Control in Low Pressure Boiler and Steam Systems in Buildings. Separate abstracts were prepared for most of the papers.

  20. Accurate, efficient, and scalable parallel simulation of mesoscale electrostatic/magnetostatic problems accelerated by a fast multipole method

    NASA Astrophysics Data System (ADS)

    Jiang, Xikai; Karpeev, Dmitry; Li, Jiyuan; de Pablo, Juan; Hernandez-Ortiz, Juan; Heinonen, Olle

    Boundary integrals arise in many electrostatic and magnetostatic problems. In computational modeling of these problems, although the integral is performed only on the boundary of a domain, its direct evaluation needs O(N2) operations, where N is number of unknowns on the boundary. The O(N2) scaling impedes a wider usage of the boundary integral method in scientific and engineering communities. We have developed a parallel computational approach that utilize the Fast Multipole Method to evaluate the boundary integral in O(N) operations. To demonstrate the accuracy, efficiency, and scalability of our approach, we consider two test cases. In the first case, we solve a boundary value problem for a ferroelectric/ferromagnetic volume in free space using a hybrid finite element-boundary integral method. In the second case, we solve an electrostatic problem involving the polarization of dielectric objects in free space using the boundary element method. The results from test cases show that our parallel approach can enable highly efficient and accurate simulations of mesoscale electrostatic/magnetostatic problems. Computing resources was provided by Blues, a high-performance cluster operated by the Laboratory Computing Resource Center at Argonne National Laboratory. Work at Argonne was supported by U. S. DOE, Office of Science under Contract No. DE-AC02-06CH11357.

  1. Corrosion and corrosion prevention in gas turbines

    NASA Technical Reports Server (NTRS)

    Mom, A. J. A.; Kolkman, H. J.

    1985-01-01

    The conditions governing the corrosion behavior in gas turbines are surveyed. Factors such as temperature, relative humidity, the presence of sulfur and nitrogen dioxide, and fuel quality are discussed. Electromechanical corrosion at relatively low temperature in compressors; oxidation; and hot corrosion (sulfidation) at high temperature in turbines are considered. Corrosion prevention by washing and rinsing, fueld additives, and corrosion resistant materials and coatings are reviewed.

  2. The solution of radiative transfer problems in molecular bands without the LTE assumption by accelerated lambda iteration methods

    NASA Technical Reports Server (NTRS)

    Kutepov, A. A.; Kunze, D.; Hummer, D. G.; Rybicki, G. B.

    1991-01-01

    An iterative method based on the use of approximate transfer operators, which was designed initially to solve multilevel NLTE line formation problems in stellar atmospheres, is adapted and applied to the solution of the NLTE molecular band radiative transfer in planetary atmospheres. The matrices to be constructed and inverted are much smaller than those used in the traditional Curtis matrix technique, which makes possible the treatment of more realistic problems using relatively small computers. This technique converges much more rapidly than straightforward iteration between the transfer equation and the equations of statistical equilibrium. A test application of this new technique to the solution of NLTE radiative transfer problems for optically thick and thin bands (the 4.3 micron CO2 band in the Venusian atmosphere and the 4.7 and 2.3 micron CO bands in the earth's atmosphere) is described.

  3. Strategies for mitigating the ionization-induced beam head erosion problem in an electron-beam-driven plasma wakefield accelerator

    NASA Astrophysics Data System (ADS)

    An, W.; Zhou, M.; Vafaei-Najafabadi, N.; Marsh, K. A.; Clayton, C. E.; Joshi, C.; Mori, W. B.; Lu, W.; Adli, E.; Corde, S.; Litos, M.; Li, S.; Gessner, S.; Frederico, J.; Hogan, M. J.; Walz, D.; England, J.; Delahaye, J. P.; Muggli, P.

    2013-10-01

    Strategies for mitigating ionization-induced beam head erosion in an electron-beam-driven plasma wakefield accelerator (PWFA) are explored when the plasma and the wake are both formed by the transverse electric field of the beam itself. Beam head erosion can occur in a preformed plasma because of a lack of focusing force from the wake at the rising edge (head) of the beam due to the finite inertia of the electrons. When the plasma is produced by field ionization from the space charge field of the beam, the head erosion is significantly exacerbated due to the gradual recession (in the beam frame) of the 100% ionization contour. Beam particles in front of the ionization front cannot be focused (guided) causing them to expand as in vacuum. When they expand, the location of the ionization front recedes such that even more beam particles are completely unguided. Eventually this process terminates the wake formation prematurely, i.e., well before the beam is depleted of its energy. Ionization-induced head erosion can be mitigated by controlling the beam parameters (emittance, charge, and energy) and/or the plasma conditions. In this paper we explore how the latter can be optimized so as to extend the beam propagation distance and thereby increase the energy gain. In particular we show that, by using a combination of the alkali atoms of the lowest practical ionization potential (Cs) for plasma formation and a precursor laser pulse to generate a narrow plasma filament in front of the beam, the head erosion rate can be dramatically reduced. Simulation results show that in the upcoming “two-bunch PWFA experiments” on the FACET facility at SLAC national accelerator laboratory the energy gain of the trailing beam can be up to 10 times larger for the given parameters when employing these techniques. Comparison of the effect of beam head erosion in preformed and ionization produced plasmas is also presented.

  4. Special aspects of corrosion control in the Arctic and Subarctic

    SciTech Connect

    Talkington, J.P.; Perrigo, L.D.

    1994-12-31

    Many engineers and scientists believe that corrosion control in the Arctic and Subarctic is easier or less demanding than control work done in more temperate parts of the world. Although temperatures lower reaction rates, there are many circumstances where other variables play overriding roles in determining what occurs with operating equipment and facilities. This paper uses examples from Alaska and other northern areas to describe some of these effects and the special arrangements necessary to combat or avoid problems. The interplay of climatic, geographic, and marine variables often create conditions that are very corrosive. Cold water oxygen concentrations may be as great as 13.5 ppm. Significant amounts of glacial silt are often found in estuarine waters leading to erosive conditions. Fluctuations of 9.5+m (30+ feet) between high and low tides significantly change external conditions twice each day. The proper use, as well as the misapplication, of vapor barriers often create more humid conditions inside structures. These conditions can lead to corroded electrical wires, contacts, and fixtures. The application of deicing chemicals may affect rebar corrosion and structural integrity. The improper seating of fasteners used in holding metal siding can lead to accelerated corrosion in windy, foggy, marine atmospheres. What occurs during the transportation of materials to Northern sites, the conditions under which those items are stored before use, and construction practice often play important roles in the subsequent performance of equipment and facilities. Remedial action that may be employed to avoid or reduce corrosion effects include common countermeasures such as cathodic protection, coatings and linings, alternation of internal/external environmental effects, and the use of anticorrosion design principles in a Northern context.

  5. Drywell corrosion stopped at Oyster Creek

    SciTech Connect

    Lipford, B.L. ); Flynn, J.C.

    1993-11-01

    This article describes the detection of corrosion on the drywell containment vessel of Oyster Creek Nuclear Plant and the application of a protective coating to repair the drywell. The topics of the article include drywell design features, identification of the problem, initial action, drywell corrosion, failure of cathodic protection, long-term repair, and repair results.

  6. Biobased polymers for corrosion protection of metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anticorrosive biobased polymers were developed in our lab. We isolated an exopolysaccharide produced by a microbe that, when coated on metal substrates, exhibited unique corrosion inhibition. Corrosion is a worldwide problem and impacts the economy, jeopardizes human health and safety, and impedes t...

  7. Controlled-Release Microcapsules for Smart Coatings for Corrosion Applications

    NASA Technical Reports Server (NTRS)

    2008-01-01

    Corrosion is a serious problem that has enormous costs and serious safety implications. Localized corrosion, such as pitting, is very dangerous and can cause catastrophic failures. The NASA Corrosion Technology Laboratory at Kennedy Space Center is developing a smart coating based on pH-sensitive microcapsules for corrosion applications. These versatile microcapsules are designed to be incorporated into a smart coating and deliver their core content when corrosion starts. Corrosion indication was the first function incorporated into the microcapsules. Current efforts are focused on incorporating the corrosion inhibition function through the encapsulation of corrosion inhibitors into water core and oil core microcapsules. Scanning electron microscopy (SEM) images of encapsulated corrosion inhibitors are shown.

  8. Corrosion effects on friction factors

    SciTech Connect

    Magleby, H.L.; Shaffer, S.J.

    1996-03-01

    This paper presents the results of NRC-sponsored material specimen tests that were performed to determine if corrosion increases the friction factors of sliding surfaces of motor-operated gate valves, which could require higher forces to close and open safety-related valves when subjected to their design basis differential pressures. Friction tests were performed with uncorroded specimens and specimens subjected to accelerated corrosion. Preliminary tests at ambient conditions showed that corrosion increased the friction factors, indicating the need for additional tests duplicating valve operating parameters at hot conditions. The additional tests showed friction factors of corroded specimens were 0.1 to 0.2 higher than for uncorroded specimens, and that the friction factors of the corroded specimens were not very dependent on contact stress or corrosion film thickness. The measured values of friction factors for the three corrosion films tested (simulating three operating times) were in the range of 0.3 to 0.4. The friction factor for even the shortest simulated operating time was essentially the same as the others, indicating that the friction factors appear to reach a plateau and that the plateau is reached quickly.

  9. Graphene coatings for protection against microbiologically induced corrosion

    NASA Astrophysics Data System (ADS)

    Krishnamurthy, Ajay

    Microbiologically induced corrosion (MIC) is a special form of electrochemical corrosion where micro-organisms affect the local environmental conditions at the metal-electrolyte interface by forming a stable biofilm. The biofilm introduces localized concentration cells, which accelerate the electrochemical corrosion rates. MIC has been found to affect many industrial systems such as sewage waste water pipes, heat exchangers, ships, underwater pipes etc. It has been traditionally eradicated by physical, biochemical and surface protection methods. The cleaning methods and the biocidal deliveries are required periodically and don't provide a permanent solution to the problem. Further, the use of biocides has been harshly criticized by environmentalists due to safety concerns associated with their usage. Surface based coatings have their own drawback of rapid degradation under harsh microbial environments. This has led to the exploration of thin, robust, inert, conformal passivation coatings for the protection of metallic surfaces from microbiologically induced corrosion. Graphene is a 2D arrangement of carbon atoms in a hexagonal honeycomb lattice. The carbon atoms are bonded to one another by sp2 hybridization and each layer of the carbon ring arrangement spans to a thickness of less than a nm. Due to its unique 2D arrangement of carbon atoms, graphene exhibits interesting in-plane and out of plane properties that have led to it being considered as the material for the future. Its excellent thermal, mechanical, electrical and optical properties are being explored in great depth to understand and realize potential applications in various technological realms. Early studies have shown the ability of bulk and monolayer graphene to protect metallic surfaces from air oxidation and solution based galvanic corrosion processes for short periods. However, the role of graphene in resisting MIC is yet to be determined, particularly over the long time spans characteristic of

  10. In-situ electrochemical study of corrosion of steel and aluminum/steel couples during cyclic corrosion test

    SciTech Connect

    Gao, G.

    1998-12-31

    Use of aluminum alloys for automotive applications is growing steadily. Galvanic corrosion is a major concern for those alloys. Because of the predominate use of steels in the automotive industry, the majority of accelerated test procedures commonly accepted by the industry are designed for cosmetic corrosion and perforation of steels. SAE 52334 and Ford Arizona Proving Ground (Ford APG) tests are two examples. Adopting those tests for galvanic corrosion of Al alloys without any fundamental understanding of the process may lead to misleading results. In this paper, electrochemical studies were conducted to examine the acceleration effects of several parameters on different types of corrosion. Galvanic corrosion of aluminum 6111 alloy and cold rolled steel (Al/ CRS) couples and general corrosion of cold rolled steel substrates were studied.

  11. Chemical Industry Corrosion Management

    SciTech Connect

    2003-02-01

    Improved Corrosion Management Could Provide Significant Cost and Energy Savings for the Chemical Industry. In the chemical industry, corrosion is often responsible for significant shutdown and maintenance costs.

  12. Coarse-mesh diffusion synthetic acceleration of the scattering source iteration scheme for one-speed slab-geometry discrete ordinates problems

    NASA Astrophysics Data System (ADS)

    Santos, Frederico P.; Filho, Hermes Alves; Barros, Ricardo C.

    2013-10-01

    The scattering source iterative (SI) scheme is traditionally applied to converge fine-mesh numerical solutions to fixed-source discrete ordinates (SN) neutron transport problems. The SI scheme is very simple to implement under a computational viewpoint. However, the SI scheme may show very slow convergence rate, mainly for diffusive media (low absorption) with several mean free paths in extent (low leakage). In this work we describe an acceleration technique based on an improved initial guess for the scattering source distribution within the slab. In other words, we use as initial guess for the fine-mesh scattering source, the coarse-mesh solution of the neutron diffusion equation with special boundary conditions to account for the classical SN prescribed boundary conditions, including vacuum boundary conditions. Therefore, we first implement a spectral nodal method that generates coarse-mesh diffusion solution that is completely free from spatial truncation errors, then we reconstruct this coarse-mesh solution within each spatial cell of the discretization grid, to further yield the initial guess for the fine-mesh scattering source in the first SN transport sweep (forward and backward) across the spatial grid. We consider a number of numerical experiments to illustrate the efficiency of the offered diffusion synthetic acceleration (DSA) technique.

  13. Materials characterization center workshop on corrosion of engineered barriers

    SciTech Connect

    Merz, M.D.; Zima, G.E.; Jones, R.H.; Westerman, R.E.

    1981-03-01

    A workshop on corrosion test procedures for materials to be used as barriers in nuclear waste repositories was conducted August 19 and 20, 1980, at the Battelle Seattle Research Center. The purpose of the meeting was to obtain guidance for the Materials Characterization Center in preparing test procedures to be approved by the Materials Review Board. The workshop identified test procedures that address failure modes of uniform corrosion, pitting and crevice corrosion, stress corrosion, and hydrogen effects that can cause delayed failures. The principal areas that will require further consideration beyond current engineering practices involve the analyses of pitting, crevice corrosion, and stress corrosion, especially with respect to quantitative predictions of the lifetime of barriers. Special techniques involving accelerated corrosion testing for uniform attack will require development.

  14. Initial Atmospheric Corrosion of Carbon Steel in Industrial Environment

    NASA Astrophysics Data System (ADS)

    Han, Wei; Pan, Chen; Wang, Zhenyao; Yu, Guocai

    2015-02-01

    The initial corrosion behavior of carbon steel subjected to Shenyang industrial atmosphere has been investigated by weight-loss measurement, scanning electron microscopy observation, x-ray diffraction, auger electron spectroscopy, and electron probe microanalysis. The experimental results reveal that the corrosion kinetics of the initial corrosion of carbon steel in industrial atmosphere follows empirical equation D = At n , and there is a corrosion rate transition from corrosion acceleration to deceleration; the corrosion products are composed of γ-FeOOH, α-FeOOH, Fe3O4, as well as FeS which is related to the existence of sulfate-reducing bacteria in the rust layers. The effect of dust particles on the corrosion evolution of carbon steel has also been discussed.

  15. Problems concerned with local erosion-corrosion of welded connections in the pipelines of a power unit at a nuclear power station

    NASA Astrophysics Data System (ADS)

    Tomarov, G. V.; Lovchev, V. N.; Gutsev, D. F.; Shipkov, A. A.; Golubeva, T. N.; Greblov, P. N.

    2012-08-01

    Results from a study aimed at analyzing the damageability and determining the mechanism due to which thinning occurs in the metal of welded connections in the feed water supply control assemblies used in power units of nuclear power stations equipped with RBMK-1000 reactors are presented together with the outcomes from calculation studies aimed at analyzing the effect of hydrodynamic characteristics on the kinetics characterizing the thinning of a welded joint and adjacent elements of a pipeline. Data from a calculation of the erosion-corrosion rate of welded connections in the divergent parts of assemblies controlling the supply of feed water in power units of nuclear power stations equipped with RBMK-1000 reactors are given.

  16. Grease Inhibits Stress-Corrosion Cracking In Bearing Race

    NASA Technical Reports Server (NTRS)

    Beatty, Robert F.; Mcvey, Scott E.

    1991-01-01

    Coating with suitable grease found to inhibit stress-corrosion cracking in bore of inner race of ball-bearing assembly operating in liquid oxygen. Protects bore and its corner radii from corrosion-initiating and -accelerating substances like moisture and contaminants, which enter during assembly. Operating life extended at low cost, and involves very little extra assembly time.

  17. Research on a new type of fiber Bragg grating based corrosion sensor

    NASA Astrophysics Data System (ADS)

    Li, Peng; Song, Shide; Wang, Xiaona; Zhou, Weijie; Zhang, Zuocai

    2015-08-01

    Investigations of the corrosion of rebars in concrete structures are widely studied because of the serious damage to concrete caused by rebar corrosion. The rebar corrosion products in reinforced concrete take up 2~6 times the volume of the rebar. Based on this principle, a new type of fiber Bragg grating (FBG) corrosion sensor is proposed in this paper, which consists of two sensors, an FBG corrosion measurement sensor to measure the expansion strain caused by rebar corrosion, and a temperature compensation sensor to eliminate the cross-sensitivity of FBG corrosion sensor. The corrosion rate is derived by the wavelength shift of FBG corrosion sensor, so rebar corrosion can be monitored and assessed by the FBG wavelength shift. A customized rebar with epoxy fixing groove is designed to install a corrosion sensor on its surface and an embedded temperature compensation sensor. The corrosion sensor is embedded in cement mortar and subsequently casted in concrete. The performance of the corrosion sensor is studied in an accelerated electrochemical corrosion test. Experimental results show that the new type of corrosion sensor has advantage of relatively large measurement range of corrosion rate. The corrosion sensor is suitable to monitor slightly and moderately corroded rebars.

  18. Corrosion of iron under alternating wet and dry conditions

    SciTech Connect

    Dunn, D.S.; Bogart, M.B.; Brossia, C.S.; Cragnolino, G.A.

    2000-05-01

    In-situ alternating current (AC) and direct current (DC) electrochemical techniques were used to determine the corrosion rate and corrosion potential of high-purity iron under alternate wet and dry conditions. Comparisons between DC electrochemical measurements and weight loss were conducted to verify the validity of the corrosion rate measurements. Identification of the corrosion products was performed using Raman spectroscopy. Corrosion products contained layers of iron oxides and oxyhydroxides. At low Cl{sup {minus}} concentrations, corrosion products consisted of lepidocrocite ({gamma}-FeOOH) and magnetite (Fe{sub 3}O{sub 4}). At higher Cl{sup {minus}} concentrations, the formation of akaganeite ({beta}-FeOOH) was observed. Corrosion rates and corrosion potentials fluctuated through-out the wet cycles depending on electrolyte layer thickness, ionic strength, and wetting cycle. Accelerated corrosion rates of high-purity iron, up to three times those observed under continuously immersed conditions, were the result of Fe(III) reduction in the corrosion product layer, increased Cl{sup {minus}} concentration during evaporation, and accelerated oxygen transport across the thin electrolyte layer.

  19. Corrosion of iron under alternating wet and dry conditions

    SciTech Connect

    Dunn, D.S.; Bogart, M.B.; Brossia, C.S.; Cragnolino, G.A.

    1999-11-01

    In-situ AC and DC electrochemical techniques were used to determine the corrosion rate and corrosion potential of high purity iron under alternate wet and dry conditions. Comparisons between DC electrochemical measurements and weight loss were also performed to verify the validity of the corrosion rate measurements. Identification of the corrosion products was performed using Raman spectroscopy. The corrosion products were found to contain layers of iron oxides and oxyhydroxides. At low chloride concentrations the corrosion products consisted of {gamma}-FeOOH and Fe{sub 3}O{sub 4}, whereas at higher chloride concentrations the formation of {beta}-FeOOH was observed. Corrosion rates and corrosion potentials fluctuated throughout the wet cycles based on electrolyte layer thickness, ionic strength, and wetting cycle. Accelerated corrosion rates of high purity iron up to 3 times that observed under continuously immersed conditions were found to be the result of Fe(III) reduction in the corrosion product layer, increased chloride concentration during evaporation, and accelerated oxygen transport across the thin electrolyte layer.

  20. The Corrosion and Corrosion Fatigue Behavior of Nickel Based Alloy Weld Overlay and Coextruded Claddings

    NASA Astrophysics Data System (ADS)

    Stockdale, Andrew

    The use of low NOx boilers in coal fired power plants has resulted in sulfidizing corrosive conditions within the boilers and a reduction in the service lifetime of the waterwall tubes. As a solution to this problem, Ni-based weld overlays are used to provide the necessary corrosion resistance however; they are susceptible to corrosion fatigue. There are several metallurgical factors which give rise to corrosion fatigue that are associated with the localized melting and solidification of the weld overlay process. Coextruded coatings offer the potential for improved corrosion fatigue resistance since coextrusion is a solid state coating process. The corrosion and corrosion fatigue behavior of alloy 622 weld overlays and coextruded claddings was investigated using a Gleeble thermo-mechanical simulator retrofitted with a retort. The experiments were conducted at a constant temperature of 600°C using a simulated combustion gas of N2-10%CO-5%CO2-0.12%H 2S. An alternating stress profile was used with a minimum tensile stress of 0 MPa and a maximum tensile stress of 300 MPa (ten minute fatigue cycles). The results have demonstrated that the Gleeble can be used to successfully simulate the known corrosion fatigue cracking mechanism of Ni-based weld overlays in service. Multilayer corrosion scales developed on each of the claddings that consisted of inner and outer corrosion layers. The scales formed by the outward diffusion of cations and the inward diffusion of sulfur and oxygen anions. The corrosion fatigue behavior was influenced by the surface finish and the crack interactions. The initiation of a large number of corrosion fatigue cracks was not necessarily detrimental to the corrosion fatigue resistance. Finally, the as-received coextruded cladding exhibited the best corrosion fatigue resistance.

  1. THE CANADIAN PERSPECTIVE ON CORROSION CONTROL: HEALTH CANADA'S CORROSION CONTROL GUIDELINE

    EPA Science Inventory

    Health Canada has proposed a Corrosion Control Guideline, based on lead, which is undergoing public consultation and expected to be finalized in 2007. In Canada, there are no regulations and little guidance to address corrosion problems and existing sampling methods are inappropr...

  2. An artifical corrosion protocol for lap-splices in aircraft skin

    NASA Technical Reports Server (NTRS)

    Shaw, Bevil J.

    1994-01-01

    This paper reviews the progress to date to formulate an artificial corrosion protocol for the Tinker AFB C/KC-135 Corrosion Fatigue Round Robin Test Program. The project has provided new test methods to faithfully reproduce the corrosion damage within a lap-splice by accelerated means, the rationale for a new laboratory test environment, and a means for corrosion damage quantification. The approach is pragmatic and the resulting artificial corrosion protocol lays the foundation for future research in the assessment of aerospace alloys. The general means for quantification of corrosion damage has been presented in a form which can be directly applied to structural integrity calculations.

  3. Monitoring corrosion in prestressed concrete beams using acoustic emission technique

    NASA Astrophysics Data System (ADS)

    ElBatanouny, Mohamed K.; Mangual, Jesé; Vélez, William; Ziehl, Paul H.; Matta, Fabio; González, Miguel

    2012-04-01

    Early detection of corrosion can help reduce the cost of maintenance and extend the service life of structures. Acoustic emission (AE) sensing has proven to be a promising method for early detection of corrosion in reinforced concrete members. A test program is presented composed of four medium-scale prestressed concrete T-beams. Three of the beams have a length of 16 ft. 4 in. (4.98 m), and one is 9 ft. 8 in. (2.95 m). In order to corrode the specimens a 3% NaCl solution was prepared, which is representative of sea salt concentration. The beams were subjected to wet-dry cycles to accelerate the corrosion process. Two of the specimens were pre-cracked prior to conditioning in order to examine the effect of crack presence. AE data was recorded continuously while half-cell potential measurements and corrosion rate by Linear Polarization Resistance (LPR) were measured daily. Corrosion current was also being acquired constantly to monitor any change in the concrete resistivity. Results indicate that the onset of corrosion may be identified using AE features, and were corroborated with measurements obtained from electrochemical techniques. Corroded areas were located using source triangulation. The results indicate that cracked specimens showed corrosion activity prior to un-cracked specimens and experienced higher corrosion rates. The level of corrosion was determined using corrosion rate results. Intensity analysis was used to link the corrosion rate and level to AE data.

  4. Cooling tower hardware corrosion studies

    SciTech Connect

    Blue, S.C.

    1983-01-31

    The data presented in this report are interim results of a continuing investigation into the corrosion resistance of metals in the environment of a large cooling tower. Some of the significant observations are as follows: the corrosion of susceptible metals occurs most rapidly in the warm fog conditions between the deck and mist filters; the application of stainless steel must be made on the basis of alloy chemistry and processing history. Some corrosion resistant alloys may develop cracking problems after improper heat treating or welding; combinations of aluminum bronze, stainless steel, and silicon bronze hardware were not susceptible to galvanic corrosion; the service life of structural steel is extended by coal tar epoxy coatings; aluminum coatings appear to protect structural steel on the tower deck and below the distribution nozzles. The corrosion of cooling tower hardware can be easily controlled through the use of 316 stainless steel and silicon bronze. The use of other materials which exhibit general resistance should be specified only after they have been tested in the form of structural assemblies such as weldments and bolted joints in each of the different tower zones.

  5. In-situ corrosion sensor for coating, testing and screening

    SciTech Connect

    Davis, G.D.; Dacres, C.M.; Krebs, L.A.

    2000-02-01

    An in-situ corrosion censor facilitates coating development and screening by detecting the early stages of corrosion well before degradation is visible. Based on electrochemical impedance spectroscopy (EIS), the sensor extends the use of this established laboratory technique from immersion only to different accelerated test conditions (such as salt fog or humidity) and ambient service environments. By enabling a direct quantitative comparison of the early stages of coating deterioration and substrate corrosion that occur in laboratory accelerated tests and service or field conditions, the laboratory tests can be validated and coatings screened more quickly.

  6. Hot corrosion of S-57, 1 cobalt-base alloy

    NASA Technical Reports Server (NTRS)

    Santoro, G. J.

    1977-01-01

    A cobalt base alloy, S-57, was hot corrosion tested in Mach 0.3 burner rig combustion gases at maximum alloy temperatures of 900 and 1000 C. Various salt concentrations were injected into the burner: 0.5, 2, 5, and 10 ppm synthetic sea salt and 4 ppm sodium sulfate (Na2SO4). S-57 underwent accelerated corrosion only under the most severe test conditions, for example, 4 ppm Na2SO4 at 900 C. The process of the accelerated corrosion was primarily sulfidation.

  7. Method for monitoring environmental and corrosion

    DOEpatents

    Glass, R.S.; Clarke, W.L. Jr.; Ciarlo, D.R.

    1995-08-01

    A corrosion sensor array is described incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis. 7 figs.

  8. Method for monitoring environmental and corrosion

    DOEpatents

    Glass, Robert S.; Clarke, Jr., Willis L.; Ciarlo, Dino R.

    1995-01-01

    A corrosion sensor array incorporating individual elements for measuring various elements and ions, such as chloride, sulfide, copper, hydrogen (pH), etc. and elements for evaluating the instantaneous corrosion properties of structural materials. The exact combination and number of elements measured or monitored would depend upon the environmental conditions and materials used which are subject to corrosive effects. Such a corrosion monitoring system embedded in or mounted on a structure exposed to the environment would serve as an early warning system for the onset of severe corrosion problems for the structure, thus providing a safety factor as well as economic factors. The sensor array is accessed to an electronics/computational system, which provides a means for data collection and analysis.

  9. Corrosion/96 conference papers

    SciTech Connect

    1996-07-01

    Topics covered by this conference include: cathodic protection in natural waters; cleaning and repassivation of building HVAC systems; worldwide opportunities in flue gas desulfurization; advancements in materials technology for use in oil and gas service; fossil fuel combustion and conversion; technology of corrosion inhibitors; computers in corrosion control--modeling and information processing; recent experiences and advances of austenitic alloys; managing corrosion with plastics; corrosion measurement technology; corrosion inhibitors for concrete; refining industry; advances in corrosion control for rail and tank trailer equipment; CO{sub 2} corrosion--mechanisms and control; microbiologically influenced corrosion; corrosion in nuclear systems; role of corrosion in boiler failures; effects of water reuse on monitoring and control technology in cooling water applications; methods and mechanisms of scale and deposit control; corrosion detection in petroleum production lines; underground corrosion control; environmental cracking--relating laboratory results and field behavior; corrosion control in reinforced concrete structures; corrosion and its control in aerospace and military hardware; injection and process addition facilities; progress reports on the results of reinspection of deaerators inspected or repaired per RP0590 criteria; near 100% volume solids coating technology and application methods; materials performance in high temperature environments containing halides; impact of toxicity studies on use of corrosion/scale inhibitors; mineral scale deposit control in oilfield related operations; corrosion in gas treating; marine corrosion; cold climate corrosion; corrosion in the pulp and paper industry; gaseous chlorine alternatives in cooling water systems; practical applications of ozone in recirculating cooling water systems; and water reuse in industry. Over 400 papers from this conference have been processed separately for inclusion on the data base.

  10. Characterization of anode stub corrosion in Hall reduction cells

    SciTech Connect

    Wang, X.; Peterson, R.D.

    1996-10-01

    Mild steel is widely used as a structural material in the aluminum smelting industry. In prebaked-anode reduction cells, the stability of the steel used as an anode stub against high temperature oxidation and corrosion is very important with regard to its full service life and maintaining aluminum purity. This paper deals with the accelerated corrosion of the steel material used as anode stubs in the presence of the sulfur-containing anode gases. Oxidized scale and the interface region of the oxidation reaction zone in a stub from a reduction cell were fully examined using SEM and X-ray diffraction. The sulfur from the bath and the anode carbon, released as SO{sub 2}, plays an important role in accelerating the anode stub corrosion process. A sulfidation-oxidation corrosion mechanism is proposed to support the corrosion phenomena observed on the steel anode pieces.

  11. Coating disbondment leads causes of external pipeline corrosion

    SciTech Connect

    Roche, M. )

    1991-04-01

    Internal corrosion has proved the most persistent corrosion problem on the approximately 670 miles of pipelines operated since 1959 by Elf Gabon. Causes include the presence of CO{sub 2} in polyphasic lines, residual oxygen and sulfate-reducing bacteria (SRB) in water-injection lines, and bacterial corrosion in crude-oil lines. External corrosion has been less troublesome, caused either by atmospheric marine exposure with frequent wetting or by disbonded coatings on buried lines. These were the major conclusions of a review conducted by the company and presented here in two parts. This article focuses on external corrosion.

  12. Sulfate-reducing bacteria inhabiting natural corrosion deposits from marine steel structures.

    PubMed

    Païssé, Sandrine; Ghiglione, Jean-François; Marty, Florence; Abbas, Ben; Gueuné, Hervé; Amaya, José Maria Sanchez; Muyzer, Gerard; Quillet, Laurent

    2013-08-01

    In the present study, investigations were conducted on natural corrosion deposits to better understand the role of sulfate-reducing bacteria (SRB) in the accelerated corrosion process of carbon steel sheet piles in port environments. We describe the abundance and diversity of total and metabolically active SRB within five natural corrosion deposits located within tidal or low water zone and showing either normal or accelerated corrosion. By using molecular techniques, such as quantitative real-time polymerase chain reaction, denaturing gel gradient electrophoresis, and sequence cloning based on 16S rRNA, dsrB genes, and their transcripts, we demonstrated a clear distinction between SRB population structure inhabiting normal or accelerated low-water corrosion deposits. Although SRB were present in both normal and accelerated low-water corrosion deposits, they dominated and were exclusively active in the inner and intermediate layers of accelerated corrosion deposits. We also highlighted that some of these SRB populations are specific to the accelerated low-water corrosion deposit environment in which they probably play a dominant role in the sulfured corrosion product enrichment. PMID:23086338

  13. Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Sidorin, Anatoly

    2010-01-01

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  14. Linear Accelerators

    SciTech Connect

    Sidorin, Anatoly

    2010-01-05

    In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.

  15. A corrosion control manual for rail rapid transit

    NASA Technical Reports Server (NTRS)

    Gilbert, L. O.; Fitzgerald, J. F., II; Menke, J. T.

    1982-01-01

    In 1979, during the planning stage of the Metropolitan Dade County Transit System, the need was expressed for a corrosion control manual oriented to urban rapid transit system use. This manual responds to that need. The objective of the manual is to aid rail rapid transit agencies by providing practical solutions to selected corrosion problems. The scope of the manual encompasses corrosion problems of the facilities of rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. It also discusses stray electric current corrosion. Both design and maintenance solutions are provided for each problem. Also included are descriptions of the types of corrosion and their causes, descriptions of rapid transit properties, a list of corrosion control committees and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual. A bibliography of papers and excerpts of reports and a glossary of frequency used terms are provided.

  16. Microbial Iron Respiration Can Protect Steel from Corrosion

    PubMed Central

    Dubiel, M.; Hsu, C. H.; Chien, C. C.; Mansfeld, F.; Newman, D. K.

    2002-01-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

  17. Microbial iron respiration can protect steel from corrosion.

    PubMed

    Dubiel, M; Hsu, C H; Chien, C C; Mansfeld, F; Newman, D K

    2002-03-01

    Microbiologically influenced corrosion (MC) of steel has been attributed to the activity of biofilms that include anaerobic microorganisms such as iron-respiring bacteria, yet the mechanisms by which these organisms influence corrosion have been unclear. To study this process, we generated mutants of the iron-respiring bacterium Shewanella oneidensis strain MR-1 that were defective in biofilm formation and/or iron reduction. Electrochemical impedance spectroscopy was used to determine changes in the corrosion rate and corrosion potential as a function of time for these mutants in comparison to the wild type. Counter to prevailing theories of MC, our results indicate that biofilms comprising iron-respiring bacteria may reduce rather than accelerate the corrosion rate of steel. Corrosion inhibition appears to be due to reduction of ferric ions to ferrous ions and increased consumption of oxygen, both of which are direct consequences of microbial respiration. PMID:11872499

  18. Internal Corrosion and Deposition Control

    EPA Science Inventory

    This chapter reviews the current knowledge of the science of corrosion control and control of scaling in drinking water systems. Topics covered include: types of corrosion; physical, microbial and chemical factors influencing corrosion; corrosion of specific materials; direct ...

  19. Multiphysics modeling of two-phase film boiling within porous corrosion deposits

    NASA Astrophysics Data System (ADS)

    Jin, Miaomiao; Short, Michael

    2016-07-01

    Porous corrosion deposits on nuclear fuel cladding, known as CRUD, can cause multiple operational problems in light water reactors (LWRs). CRUD can cause accelerated corrosion of the fuel cladding, increase radiation fields and hence greater exposure risk to plant workers once activated, and induce a downward axial power shift causing an imbalance in core power distribution. In order to facilitate a better understanding of CRUD's effects, such as localized high cladding surface temperatures related to accelerated corrosion rates, we describe an improved, fully-coupled, multiphysics model to simulate heat transfer, chemical reactions and transport, and two-phase fluid flow within these deposits. Our new model features a reformed assumption of 2D, two-phase film boiling within the CRUD, correcting earlier models' assumptions of single-phase coolant flow with wick boiling under high heat fluxes. This model helps to better explain observed experimental values of the effective CRUD thermal conductivity. Finally, we propose a more complete set of boiling regimes, or a more detailed mechanism, to explain recent CRUD deposition experiments by suggesting the new concept of double dryout specifically in thick porous media with boiling chimneys.

  20. Corrosion behaviour of 316L stainless steel and anti-corrosion materials in a high acidified chloride solution

    NASA Astrophysics Data System (ADS)

    Jin, Z. H.; Ge, H. H.; Lin, W. W.; Zong, Y. W.; Liu, S. J.; Shi, J. M.

    2014-12-01

    The corrosion behaviour of a type 316L (UNS S31603) stainless steel (SS) expansion joint in a simulated leaching solution of sediment on blast furnace gas pipeline in a power plant is investigated by using dynamic potential polarization curves, electrochemical impedance spectroscopy (EIS), optical microscope, atomic force microscope (AFM) and Scan Kelvin Probe (SKP). Severe general corrosion accompanied by pitting corrosion occurs on the type 316L SS surface in this solution. As the immersion period increases, the charge transfer resistance Rct decreases, the dissolution rate accelerates, the surface roughness increases and the surface potential difference enhances significantly. Then eight corrosion-resistant materials are tested, the corrosion rates of type 254SMo SS, type 2507 SS and TA2 are relatively minor in the solution. The corrosion resistance properties of TA2 is most excellent, indicating it would be the superior material choice for blast furnace gas pipeline.

  1. Systematic program and internal inspection keys to corrosion control

    SciTech Connect

    Roche, M. )

    1991-04-08

    A review of corrosion problems on the 670-mile land and offshore system operated by Elf Gabon indicated that internal corrosion has been the most persistent problem. The company has operated the system since 1959. Causes include the presence of CO{sub 2} in polyphasic lines, residual oxygen and sulfate-reducing bacteria SRBP in water-injection lines, and bacterial corrosion in crude-oil lines. External corrosion has been less troublesome, caused either by atmospheric marine exposure with frequent wetting or by disbonded coatings on buried pipes.

  2. Corrosion inhibiting organic coatings

    SciTech Connect

    Sasson, E.

    1984-10-16

    A corrosion inhibiting coating comprises a mixture of waxes, petroleum jelly, a hardener and a solvent. In particular, a corrosion inhibiting coating comprises candelilla wax, carnauba wax, microcrystalline waxes, white petrolatum, an oleoresin, lanolin and a solvent.

  3. Duralumin and Its Corrosion

    NASA Technical Reports Server (NTRS)

    Nelson, WM

    1927-01-01

    The types of corrosion and factors of corrosion of duralumin are investigated. Salt water is the most common of the corroding media with which designers have to contend in using duralumin in aircraft and ships.

  4. A New Corrosion Sensor to Determine the Start and Development of Embedded Rebar Corrosion Process at Coastal Concrete

    PubMed Central

    Xu, Chen; Li, Zhiyuan; Jin, Weiliang

    2013-01-01

    The corrosion of reinforcements induced by chloride has resulted to be one of the most frequent causes of their premature damage. Most corrosion sensors were designed to monitor corrosion state in concrete, such as Anode-Ladder-System and Corrowatch System, which are widely used to monitor chloride ingress in marine concrete. However, the monitoring principle of these corrosion sensors is based on the macro-cell test method, so erroneous information may be obtained, especially from concrete under drying or saturated conditions due to concrete resistance taking control in macro-cell corrosion. In this paper, a fast weak polarization method to test corrosion state of reinforcements based on electrochemical polarization dynamics was proposed. Furthermore, a new corrosion sensor for monitoring the corrosion state of concrete cover was developed based on the proposed test method. The sensor was tested in cement mortar, with dry-wet cycle tests to accelerate the chloride ingress rate. The results show that the corrosion sensor can effectively monitor chloride penetration into concrete with little influence of the relative humidity in the concrete. With a reasonable corrosion sensor electrode arrangement, it seems the Ohm-drop effect measured by EIS can be ignored, which makes the tested electrochemical parameters more accurate. PMID:24084117

  5. Erosion-Corrosion Property of CeO2-Modified HVOF WC-Co Coating

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Hang, Zongqiu; Chen, Hui; Ceng, Shengbo; Gou, Guoqing; Wang, Xiaomin; Tu, Mingjing; Wu, Xiangyang

    2016-04-01

    Rare-earth elements have been widely used in materials manufacturing to improve hardness and toughness. In this work, conventional, nanostructured, and CeO2-modified WC-12Co powders were sprayed using high-velocity oxygen flame spraying. The erosion-corrosion behavior and interaction of erosion and corrosion of the coatings in 3.5 wt.% NaCl solution were investigated. In situ observation was employed to analyze the failure mechanism. The results showed that the CeO2-modified WC-12Co coating possessed the best erosion-corrosion resistance, while the lowest corrosion resistance was exhibited by the conventional WC-12Co coating. The results also suggested that the erosion-corrosion mechanism in the three coatings was dominated by corrosion-accelerated erosion. However, the extent of acceleration of erosion by corrosion differed.

  6. Can Accelerators Accelerate Learning?

    NASA Astrophysics Data System (ADS)

    Santos, A. C. F.; Fonseca, P.; Coelho, L. F. S.

    2009-03-01

    The 'Young Talented' education program developed by the Brazilian State Funding Agency (FAPERJ) [1] makes it possible for high-schools students from public high schools to perform activities in scientific laboratories. In the Atomic and Molecular Physics Laboratory at Federal University of Rio de Janeiro (UFRJ), the students are confronted with modern research tools like the 1.7 MV ion accelerator. Being a user-friendly machine, the accelerator is easily manageable by the students, who can perform simple hands-on activities, stimulating interest in physics, and getting the students close to modern laboratory techniques.

  7. PARTICLE ACCELERATOR

    DOEpatents

    Teng, L.C.

    1960-01-19

    ABS>A combination of two accelerators, a cyclotron and a ring-shaped accelerator which has a portion disposed tangentially to the cyclotron, is described. Means are provided to transfer particles from the cyclotron to the ring accelerator including a magnetic deflector within the cyclotron, a magnetic shield between the ring accelerator and the cyclotron, and a magnetic inflector within the ring accelerator.

  8. Using the PubMatrix literature-mining resource to accelerate student-centered learning in a veterinary problem-based learning curriculum.

    PubMed

    David, John; Irizarry, Kristopher J L

    2009-01-01

    Problem-based learning (PBL) creates an atmosphere in which veterinary students must take responsibility for their own education. Unlike a traditional curriculum where students receive discipline-specific information by attending formal lectures, PBL is designed to elicit self-directed, student-centered learning such that each student determines (1) what he/she does not know (learning issues), (2) what he/she needs to learn, (3) how he/she will learn it, and (4) what resources he/she will use. One of the biggest challenges facing students in a PBL curriculum is efficient time management while pursuing learning issues. Bioinformatics resources, such as the PubMatrix literature-mining tool, allow access to tremendous amounts of information almost instantaneously. To accelerate student-centered learning it is necessary to include resources that enhance the rate at which students can process biomedical information. Unlike using the PubMed interface directly, the PubMatrix tool enables users to automate queries, allowing up to 1,000 distinct PubMed queries to be executed per single PubMatrix submission. Users may submit multiple PubMatrix queries per session, resulting in the ability to execute tens of thousands of PubMed queries in a single day. The intuitively organized results, which remain accessible from PubMatrix user accounts, enable students to rapidly assimilate and process hundreds of thousands of individual publication records as they relate to the student's specific learning issues and query terms. Subsequently, students can explore substantially more of the biomedical publication landscape per learning issue and spend a greater fraction of their time actively engaged in resolving their learning issues. PMID:19625669

  9. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Deramus, G. E., Jr.

    1977-01-01

    Problems dealing with corrosion and corrosion protection of solar heating and cooling systems are discussed. A test program was conducted to find suitable and effective corrosion inhibitors for systems employing either water or antifreeze solutions for heat transfer and storage. Aluminum-mild-steel-copper-stainless steel assemblies in electrical contact were used to simulate a multimetallic system which is the type most likely to be employed. Several inhibitors show promise for this application.

  10. Rebar corrosion monitoring in concrete structure under salt water enviroment using fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Pan, Yuheng; Liu, Tiegen; Jiang, Junfeng; Liu, Kun; Wang, Shuang; He, Pan; Yan, Jinlin

    2015-08-01

    Monitoring corrosion of steel reinforcing bars is critical for the durability and safety of reinforced concrete structures. Corrosion sensors based on fiber optic have proved to exhibit meaningful benefits compared with the conventional electric ones. In recent years, Fiber Bragg Grating (FBG) has been used as a new kind of sensing element in an attempt to directly monitor the corrosion in concrete structure due to its remarkable advantages. In this paper, we present a novel kind of FBG based rebar corrosion monitoring sensor. The rebar corrosion is detected by volume expansion of the corroded rebar by transferring it to the axial strain of FBG when concrete structure is soaked in salt water. An accelerated salt water corrosion test was performed. The experiment results showed the corrosion can be monitored effectively and the corrosion rate is obtained by volume loss rate of rebar.

  11. Corrosion performance of aluminum in coal railcars

    SciTech Connect

    Hersh, J.F.

    1988-01-01

    Aluminum has been used for construction of coal railcars and on an experimental basis as a metallized coating over steel railcars. When aluminum is used in areas which contact the lading, resistance to general corrosion has been outstanding. Galvanic corrosion of joints which connect the aluminum to a steel undercarriage has not been a problem provided appropriate measures were taken during vehicle construction. Laboratory test data are presented which illustrate the impact of variations in joint preparation on galvanic corrosion performance. Painting the steel and the use of a sealant are recommended to obtain satisfactory long term joint performance. The corrosion performance and long term durability of an aluminum metallized coating has been demonstrated when applied to new cars constructed of carbon steel. Test results of coating durability when applied to cars constructed of constructed of weathering steel or carbon steel which were in revenue coal service prior to coating have been mixed.

  12. Superheater Corrosion Produced By Biomass Fuels

    SciTech Connect

    Sharp, William; Singbeil, Douglas; Keiser, James R

    2012-01-01

    About 90% of the world's bioenergy is produced by burning renewable biomass fuels. Low-cost biomass fuels such as agricultural wastes typically contain more alkali metals and chlorine than conventional fuels. Although the efficiency of a boiler's steam cycle can be increased by raising its maximum steam temperature, alkali metals and chlorine released in biofuel boilers cause accelerated corrosion and fouling at high superheater steam temperatures. Most alloys that resist high temperature corrosion protect themselves with a surface layer of Cr{sub 2}O{sub 3}. However, this Cr{sub 2}O{sub 3} can be fluxed away by reactions that form alkali chromates or volatilized as chromic acid. This paper reviews recent research on superheater corrosion mechanisms and superheater alloy performance in biomass boilers firing black liquor, biomass fuels, blends of biomass with fossil fuels and municipal waste.

  13. Electrochemical corrosion testing: An effective tool for corrosion inhibitor evaluation

    SciTech Connect

    Bartley, L.S.; Van de Ven, P.; Mowlem, J.K.

    1996-10-01

    Corrosivity of an Antifreeze/Coolant can lead to localized attacks which are a major cause for metal failure. To prevent this phenomenon, specific corrosion inhibitors are used to protect the different metals in service. This paper will discuss the electrochemical principles behind corrosion, Realized corrosion and corrosion inhibition. It will also discuss electrochemical techniques which allow for the evaluation of these inhibitors.

  14. Cause of stress-corrosion cracking in pipe

    SciTech Connect

    Christman, T.K.; Beavers, J.A.

    1987-01-05

    Carbonate-bicarbonate has been identified as the environmental species responsible for stress-corrosion cracking (SCC) in the majority of studied field failures of natural-gas pipelines. Battelle Columbus Division, Columbus, Ohio, studied approximately 30 SCC field failures of natural-gas pipelines form a 20-year period beginning in 1965. The results of the study also reject hydroxide (caustic) as a significant factor in these failures. Stress-corrosion cracking in natural-gas transmission pipelines has been recognized as a serious problem for a number of years. But there remains considerable controversy concerning the environmental species responsible for the cracking. One opinion has held that carbonate-bicarbonate promotes cracking, while another attributes the cracking to hydroxide (caustic). This issue is important because the feasibility of mitigation procedures based on potential control depend upon the chemical species responsible for the cracking. Moreover, it is important for the laboratory studies aimed at SCC mitigation to simulate closely the field failures. Both carbonate/bicarbonate and caustic environments can result from application of cathodic protection to a pipeline. The cathodic current applied to the pipeline accelerates the rate of the reduction reactions occurring on the pipe surface, promoting generation of hydroxide.

  15. Evaluation of corrosion effect in reinforced concrete by chloride exposure

    NASA Astrophysics Data System (ADS)

    Loreto, G.; Di Benedetti, M.; Iovino, R.; Nanni, A.; Gonzalez, M. A.

    2011-04-01

    Durability is generally described as the ability of a material to maintain its physical and mechanical properties over time. In reinforced concrete (RC) structures, concrete is the ideal material to protect the steel reinforcement given its high alkalinity. In environments subjected to highly aggressive conditions, mostly due to the presence of chlorides, concrete may lose its protective characteristics and allow for accelerated ageing. Concrete degradation and steel reinforcement corrosion are phenomena closely connected. The aim of this research work is the characterization of the relationship between steel reinforcement corrosion and concrete degradation under accelerated ageing in a 3% sodium chloride solution. The method of linear polarization is used for identification of the corrosion rate of the steel bar. Additionally, the values of concrete residual strength are obtained, and correlated to both the corrosion rate and width of concrete cracks. Finally, the prediction of the concrete cover useful life is estimated.

  16. Atomistic insights into aqueous corrosion of copper.

    SciTech Connect

    Jeon, B.; Sankaranarayanan, S. K. R. S.; van Duin, A. C. T.; Ramanathan, S.

    2011-06-21

    Corrosion is a fundamental problem in electrochemistry and represents a mode of failure of technologically important materials. Understanding the basic mechanism of aqueous corrosion of metals such as Cu in presence of halide ions is hence essential. Using molecular dynamics simulations incorporating reactive force-field (ReaxFF), the interaction of copper substrates and chlorine under aqueous conditions has been investigated. These simulations incorporate effects of proton transfer in the aqueous media and are suitable for modeling the bond formation and bond breakage phenomenon that is associated with complex aqueous corrosion phenomena. Systematic investigation of the corrosion process has been carried out by simulating different chlorine concentration and solution states. The structural and morphological differences associated with metal dissolution in the presence of chloride ions are evaluated using dynamical correlation functions. The simulated atomic trajectories are used to analyze the charged states, molecular structure and ion density distribution which are utilized to understand the atomic scale mechanism of corrosion of copper substrates under aqueous conditions. Increased concentration of chlorine and higher ambient temperature were found to expedite the corrosion of copper. In order to study the effect of solution states on the corrosion resistance of Cu, partial fractions of proton or hydroxide in water were configured, and higher corrosion rate at partial fraction hydroxide environment was observed. When the Cl{sup -} concentration is low, oxygen or hydroxide ion adsorption onto Cu surface has been confirmed in partial fraction hydroxide environment. Our study provides new atomic scale insights into the early stages of aqueous corrosion of metals such as copper.

  17. Corrosion and stress corrosion cracking in coal liquefaction processes

    SciTech Connect

    Baylor, V. B.; Keiser, J. R.

    1980-01-01

    The liquefaction of coal to produce clean-burning synthetic fuels has been demonstrated at the pilot plant level. However, some significant materials problems must be solved before scale-up to commercial levels of production can be completed. Failures due to inadequate materials performance have been reported in many plant areas: in particular, stress corrosion cracking has been found in austenitic stainless steels in the reaction and separation areas and several corrosion has been observed in fractionation components. In order to screen candidate materials of construction, racks of U-bend specimens in welded and as-wrought conditions and unstressed surveillance coupons were exposed in pilot plant vessels and evaluated. Failed components were analyzed on-site and by subsequent laboratory work. Laboratory tests were also performed. From these studies alloys have been identified that are suitable for critical plant locations. 19 figures, 7 tables.

  18. High temperature alkali corrosion in high velocity gases

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Sidik, S. M.; Deadmore, D. L.

    1981-01-01

    The effects of potential impurities in coal derived liquids such as Na, K, Mg, Ca and Cl on the accelerated corrosion of IN-100, U-700, IN-792 and Mar-M509 were investigated using a Mach 0.3 burner rig for times to 1000 hours in one hour cycles. These impurities were injected in combination as aqueous solutions into the combustor of the burner rig. The experimental matrix utilized was designed statistically. The extent of corrosion was determined by metal recession. The metal recession data were fitted by linear regression to a polynomial expression which allows both interpolation and extrapolation of the data. As anticipated, corrosion increased rapidly with Na and K, and a marked maximum in the temperature response was noted for many conditions. In contrast, corrosion decreased somewhat as the Ca, Mg and Cl contents increased. Extensive corrosion was observed at concentrations of Na and K as low as 0.1 PPM at long times.

  19. Acceleration in astrophysics

    SciTech Connect

    Colgate, S.A.

    1993-12-31

    The origin of cosmic rays and applicable laboratory experiments are discussed. Some of the problems of shock acceleration for the production of cosmic rays are discussed in the context of astrophysical conditions. These are: The presumed unique explanation of the power law spectrum is shown instead to be a universal property of all lossy accelerators; the extraordinary isotropy of cosmic rays and the limited diffusion distances implied by supernova induced shock acceleration requires a more frequent and space-filling source than supernovae; the near perfect adiabaticity of strong hydromagnetic turbulence necessary for reflecting the accelerated particles each doubling in energy roughly 10{sup 5} to {sup 6} scatterings with negligible energy loss seems most unlikely; the evidence for acceleration due to quasi-parallel heliosphere shocks is weak. There is small evidence for the expected strong hydromagnetic turbulence, and instead, only a small number of particles accelerate after only a few shock traversals; the acceleration of electrons in the same collisionless shock that accelerates ions is difficult to reconcile with the theoretical picture of strong hydromagnetic turbulence that reflects the ions. The hydromagnetic turbulence will appear adiabatic to the electrons at their much higher Larmor frequency and so the electrons should not be scattered incoherently as they must be for acceleration. Therefore the electrons must be accelerated by a different mechanism. This is unsatisfactory, because wherever electrons are accelerated these sites, observed in radio emission, may accelerate ions more favorably. The acceleration is coherent provided the reconnection is coherent, in which case the total flux, as for example of collimated radio sources, predicts single charge accelerated energies much greater than observed.

  20. Flow-induced corrosion behavior of absorbable magnesium-based stents.

    PubMed

    Wang, Juan; Giridharan, Venkataraman; Shanov, Vesselin; Xu, Zhigang; Collins, Boyce; White, Leon; Jang, Yongseok; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2014-12-01

    The aim of this work was to study corrosion behavior of magnesium (Mg) alloys (MgZnCa plates and AZ31 stents) under varied fluid flow conditions representative of the vascular environment. Experiments revealed that fluid hydrodynamics, fluid flow velocity and shear stress play essential roles in the corrosion behavior of absorbable magnesium-based stent devices. Flow-induced shear stress (FISS) accelerates the overall corrosion (including localized, uniform, pitting and erosion corrosions) due to the increased mass transfer and mechanical force. FISS increased the average uniform corrosion rate, the localized corrosion coverage ratios and depths and the removal rate of corrosion products inside the corrosion pits. For MgZnCa plates, an increase of FISS results in an increased pitting factor but saturates at an FISS of ∼0.15Pa. For AZ31 stents, the volume loss ratio (31%) at 0.056Pa was nearly twice that (17%) at 0Pa before and after corrosion. Flow direction has a significant impact on corrosion behavior as more severe pitting and erosion corrosion was observed on the back ends of the MgZnCa plates, and the corrosion product layer facing the flow direction peeled off from the AZ31 stent struts. This study demonstrates that flow-induced corrosion needs be understood so that Mg-based stents in vascular environments can be effectively designed. PMID:25200844

  1. Sensors for aircraft corrosion -- Review and future developments

    SciTech Connect

    Tullmin, M.A.A.; Roberge, P.R.; Little, M.A.

    1997-12-01

    In the Canadian Forces, as for other aircraft operators, the need has arise to utilize new tools for managing corrosion problems more cost effectively. In this context, the role of aircraft corrosion sensors and the current state of this technological field was reviewed, together with identifying future development work. Three separate aircraft corrosion surveillance application areas have been defined, as a basis for evaluating the strengths and weaknesses of various corrosion sensor technologies. At present, the biggest technical shortcomings exist for the important task of reducing unnecessary inspections. The development of smart sensors integrated into the aircraft structure is recommended for this requirement.

  2. Flow accelerated organic coating degradation

    NASA Astrophysics Data System (ADS)

    Zhou, Qixin

    Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as

  3. Corrosion on steam-side heat exchanger tubes

    SciTech Connect

    Arevalo, A.; Esparza, P.; Bas, C.G.; Morales, J.; Gonzalez, S.; Sanchez, S.R. de

    1996-01-01

    Two corrosion cases occurred on the steam side of tubes in a heat exchanger in a central power station which used seawater as a coolant. The first case is stress corrosion cracking in the presence of oxygen and ammonia with through-wall cracks that originated in dealloyed cavities. The second case describes high-pressure, high-temperature steam impinging the tubes, leading to deep erosion on the tube`s external side. Erosion-corrosion accelerated on the seawater side because heating decreased the critical flow rate and enhanced formation of deposits which were obstacles to the flow.

  4. Susceptibility of stainless steel weldments to microbiologically influenced corrosion

    SciTech Connect

    Borenstein, S.W.

    1993-12-31

    Microbiologically influenced corrosion (MIC) is the term used for the phenomenon where corrosion is initiated or accelerated by microorganisms. Biofilms of bacteria form on metal surfaces when exposed to natural waters. The activity of these biofilms and how they attach themselves to metal surfaces directly influence corrosion mechanisms. This paper describes the mechanisms for MIC and the factors which influence the susceptibility of austenitic stainless steel weldments to MIC. The metallurgical, microbiological and electrochemical factors that influence MIC are discussed. Case histories of MIC-related failures and field test results of austenitic stainless steel weldments in various welded conditions are presented.

  5. SRB seawater corrosion project

    NASA Technical Reports Server (NTRS)

    Bozack, M. J.

    1991-01-01

    The corrosion behavior of 2219 aluminum when exposed to seawater was characterized. Controlled corrosion experiments at three different temperatures (30, 60 and 100 C) and two different environments (seawater and 3.5 percent salt solution) were designed to elucidate the initial stages in the corrosion process. It was found that 2219 aluminum is an active catalytic surface for growth of Al2O3, NaCl, and MgO. Formation of Al2O3 is favored at lower temperatures, while MgO is favored at higher temperatures. Visible corrosion products are formed within 30 minutes after seawater exposure. Corrosion characteristics in 3.5 percent salt solution are different than corrosion in seawater. Techniques utilized were: (1) scanning electron microscopy, (2) energy dispersive x-ray spectroscopy, and (3) Auger electron spectroscopy.

  6. Novel corrosion inhibitor technology

    SciTech Connect

    Van de Ven, P.; Fritz, P.; Pellet, R.

    1999-11-01

    A novel, patented corrosion inhibitor technology has been identified for use in heat transfer applications such as automotive and heavy-duty coolant. The new technology is based on a low-toxic, virtually depletion-free carboxylic acid corrosion inhibitor package that performs equally well in mono ethylene glycol and in less toxic propylene glycol coolants. An aqueous inhibitor concentrate is available to provide corrosion protection where freezing protection is not an issue. In the present paper, this inhibitor package is evaluated in the different base fluids: mono ethylene glycol, mono propylene glycol and water. Results are obtained in both standardized and specific corrosion tests as well as in selected field trials. These results indicate that the inhibitor package remains effective and retains the benefits previously identified in automotive engine coolant applications: excellent corrosion protection under localized conditions, general corrosion conditions as well as at high temperature.

  7. Corrosion protection of low-carbon steel using exopolysaccharide coatings from Leuconostoc mesenteroides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. This research investigates the inhibition of corrosive behavior of SAE1010 steel by bacterial exopolysaccharides. Electrochemical Impedance Spectroscopy was used to evaluate the corrosion inhibition of diffe...

  8. Electrochemical corrosion studies

    NASA Technical Reports Server (NTRS)

    Knockemus, W. W.

    1986-01-01

    The objective was to gain familiarity with the Model 350 Corrosion Measurement Console, to determine if metal protection by grease coatings can be measured by the polarization-resistance method, and to compare corrosion rates of 4130 steel coated with various greases. Results show that grease protection of steel may be determined electrochemically. Studies were also conducted to determine the effectiveness of certain corrosion inhibitors on aluminum and steel.

  9. Effective corrosion monitoring

    SciTech Connect

    Britton, C.F.; Tofield, B.C.

    1988-04-01

    The results of two surveys (conducted in 1981 and 1984) of users of corrosion monitoring equipment are described. The benefits to be obtained from a well-designed corrosion monitoring system, especially if a corrosion control program is used, are outlined together with the difficulties and barriers that can obstruct successful application. Developing methods such as AC impedance, electrochemical noise, and thin layer activation are discussed in view of the comments received from the surveys.

  10. Microbiological corrosion control in a cooling water system

    SciTech Connect

    Honneysett, D.G.; vanden Bergh, W.D.; O'Brien, P.F.

    1985-10-01

    The failure of a corrosion control program in a closed cooling water system coincided with the use of reclaimed sewage water and the contamination of the system with oil. Other problems were increased corrosion rates, downward pH excursions, increased fouling by corrosion by-products, and increased microbiological activity in the system. The major cause of corrosion was microbiological in origin. The unsuccessful use of a biocide led to the initiation of a full-scale microbiological investigation. The nature of the microflora was determined, biocide selection tests made, and an effective control treatment program initiated. Chromate corrosion treatment was replaced by a coordinated program using an organic filming corrosion inhibitor, a polyacrylate/phosphonate dispersant, and a combination of biocides.

  11. Evaluation of corrosion testing techniques for selection of corrosion resistant alloys for sour gas service

    SciTech Connect

    Bhavsar, R.B.; Hibner, E.L.

    1996-08-01

    Slow strain rate (SSR) and C-ring stress corrosion cracking (SCC) tests have historically been used to screen alloys for sour gas environments. The relevance of these testing techniques in predicting actual field corrosion behavior was evaluated for age-hardenable nickel base alloy 925 (UNS N09925) and alloy 718 (UNS N07718). While SSR testing provides an acceptable accelerated screening tool for ranking alloys in sour oil field environments, C-ring SCC testing ranks alloys higher in sour environments than SSR testing.

  12. EXPERT PANEL OVERSIGHT COMMITTEE ASSESSMENT OF FY2008 CORROSION AND STRESS CORROSION CRACKING SIMULANT TESTING PROGRAM

    SciTech Connect

    BOOMER KD

    2009-01-08

    The Expert Panel Oversight Committee (EPOC) has been overseeing the implementation of selected parts of Recommendation III of the final report, Expert Panel workshop for Hanford Site Double-Shell Tank Waste Chemistry Optimization, RPP-RPT-22126. Recommendation III provided four specific requirements necessary for Panel approval of a proposal to revise the chemistry control limits for the Double-Shell Tanks (DSTs). One of the more significant requirements was successful performance of an accelerated stress corrosion cracking (SCC) experimental program. This testing program has evaluated the optimization of the chemistry controls to prevent corrosion in the interstitial liquid and supernatant regions of the DSTs.

  13. Microsensors for corrosion control

    SciTech Connect

    Chawla, S.K.; Anguish, T.; Payer, J.H. )

    1990-05-01

    Sensors have been developed and manufactured by microelectronic fabrication techniques to directly measure corrosion rates and to determine the effectiveness of corrosion control systems. Microsensors based on measurements of corrosion rate by linear polarization, electrical resistance change, and galvanic currents have been devised. Analytical measurements by potentiometric and amperometric techniques using thick-film planar transducers are illustrated. The use of generic sensor elements individually and in combination to attest the status of corrosion control and to provide data for the evaluation of future performance is highlighted.

  14. Corrosion Detection Devices

    SciTech Connect

    Howard, B.

    2003-12-01

    Nondestructive Examination Systems' (NDE) specialists at the Department of Energy's Savannah River Site have unique, remotely controllable, corrosion detection capabilities. The corrosion detection devices most frequently used are automated ultrasonic mapping systems, digital radiography imaging devices, infrared imaging, and eddy current mapping systems. These devices have been successfully used in a variety of applications, some of which involve high levels of background radiation. Not only is corrosion located and mapped but other types of anomalies such as cracks have been detected and characterized. Examples of actual corrosion that has been detected will be discussed along with the NDE systems that were used.

  15. Corrosion in bioprocessing applications.

    PubMed

    Junker, Beth

    2009-01-01

    Corrosion in bioprocessing applications is described for a 25-year-old bioprocessing pilot plant facility. Various available stainless steel alloys differ greatly in properties owing to the impact of specific alloying elements and their concentrations. The alloy property evaluated was corrosion resistance as a function of composition under typical bioprocessing conditions such as sterilization, fermentation, and cleaning. Several non-uniform forms of corrosion relevant to bioprocessing applications (e.g., pitting, crevice corrosion, intergranular attack) were investigated for their typical causes and effects, as well as alloy susceptibility. Next, the corrosion resistance of various alloys to specific bioprocessing-relevant sources of corrosion (e.g., medium components, acids/bases used for pH adjustment, organic acid by-products) was evaluated, along with the impact of temperature on corrosion progression. Best practices to minimize corrosion included considerations for fabrication (e.g., welding, heat treatments) and operational (e.g., sterilization, media component selection, cleaning) approaches. Assessments and repair strategies for observed corrosion events were developed and implemented, resulting in improved vessel and overall facility longevity. PMID:18512080

  16. Plasma accelerators

    SciTech Connect

    Ruth, R.D.; Chen, P.

    1986-03-01

    In this paper we discuss plasma accelerators which might provide high gradient accelerating fields suitable for TeV linear colliders. In particular we discuss two types of plasma accelerators which have been proposed, the Plasma Beat Wave Accelerator and the Plasma Wake Field Accelerator. We show that the electric fields in the plasma for both schemes are very similar, and thus the dynamics of the driven beams are very similar. The differences appear in the parameters associated with the driving beams. In particular to obtain a given accelerating gradient, the Plasma Wake Field Accelerator has a higher efficiency and a lower total energy for the driving beam. Finally, we show for the Plasma Wake Field Accelerator that one can accelerate high quality low emittance beams and, in principle, obtain efficiencies and energy spreads comparable to those obtained with conventional techniques.

  17. Scaling FFAG accelerator for muon acceleration

    SciTech Connect

    Lagrange, JB.; Planche, T.; Mori, Y.

    2011-10-06

    Recent developments in scaling fixed field alternating gradient (FFAG) accelerators have opened new ways for lattice design, with straight sections, and insertions like dispersion suppressors. Such principles and matching issues are detailed in this paper. An application of these new concepts is presented to overcome problems in the PRISM project.

  18. Eddy current detection of pitting corrosion around fastener holes

    NASA Astrophysics Data System (ADS)

    Heida, J. H.; Thart, W. G. J.

    1995-01-01

    An evaluation of the eddy current technique for the detection and depth assessment of corrosion around fastener holes in F-16 lower wing skins is described. The corrosion type in this structure is pitting corrosion at the countersink edge of the fastener holes. Due to a corrosion clean-up limit of only 1.5 - 2.5 percent, a maximum thickness reduction in the range of 0.08 - 0.32 mm is allowed (depending on local skin thickness). This specifies the needed sensitivity for in-service corrosion inspection. In the evaluation use was made of specimens cut out of the F-16 lower wing skin structure. In total twelve specimens were exposed to an accelerated corrosion test (EXCO-test). Eddy current inspection of the specimens with installed fasteners was performed with a standard eddy scope and four different eddy current probes. After the eddy current inspection cross-sections of the twelve-specimens were made to determine the extent of pitting corrosion at the countersink edges. After evaluation of the inspection results the following conclusions can be drawn: for in-service detection of countersink edge corrosion standard visual inspection is the preferred technique regarding the simplicity, sensitivity and reliability of inspection; and for the purpose of depth assessment the eddy current technique is capable of detecting countersink edge corrosion with a depth from about 0.1 mm. Due to the corrosion clean-up limit of only 1.5 - 2.5 percent (0.08 - 0.32 mm), however, the eddy current technique is considered not applicable for in-service depth assessment of countersink edge corrosion in F-16 lower wing skins.

  19. Corrosion of Carbon Steel and Corrosion-Resistant Rebars in Concrete Structures Under Chloride Ion Attack

    NASA Astrophysics Data System (ADS)

    Mohamed, Nedal; Boulfiza, Mohamed; Evitts, Richard

    2013-03-01

    Corrosion of reinforced concrete is the most challenging durability problem that threatens reinforced concrete structures, especially structures that are subject to severe environmental conditions (i.e., highway bridges, marine structures, etc.). Corrosion of reinforcing steel leads to cracking and spalling of the concrete cover and billions of dollars are spent every year on repairing such damaged structures. New types of reinforcements have been developed to avoid these high-cost repairs. Thus, it is important to study the corrosion behavior of these new types of reinforcements and compare them to the traditional carbon steel reinforcements. This study aimed at characterizing the corrosion behavior of three competing reinforcing steels; conventional carbon steel, micro-composite steel (MMFX-2) and 316LN stainless steel, through experiments in carbonated and non-carbonated concrete exposed to chloride-laden environments. Synthetic pore water solutions have been used to simulate both cases of sound and carbonated concrete under chloride ions attack. A three-electrode corrosion cell is used for determining the corrosion characteristics and rates. Multiple electrochemical techniques were applied using a Gamry PC4™ potentiostat manufactured by Gamry Instruments (Warminster, PA). DC corrosion measurements were applied on samples subjected to fixed chloride concentration in the solution.

  20. Corrosion control and disinfection studies in spacecraft water systems. [considering Saturn 5 orbital workshop

    NASA Technical Reports Server (NTRS)

    Shea, T. G.

    1974-01-01

    Disinfection and corrosion control in the water systems of the Saturn 5 Orbital Workshop Program are considered. Within this framework, the problem areas of concern are classified into four general areas: disinfection; corrosion; membrane-associated problems of disinfectant uptake and diffusion; and taste and odor problems arising from membrane-disinfectant interaction.

  1. Ultrasonic Measurement of Erosion/corrosion Rates in Industrial Piping Systems

    NASA Astrophysics Data System (ADS)

    Sinclair, A. N.; Safavi, V.; Honarvar, F.

    2011-06-01

    Industrial piping systems that carry aggressive corrosion or erosion agents may suffer from a gradual wall thickness reduction that eventually threatens pipe integrity. Thinning rates could be estimated from the very small change in wall thickness values measured by conventional ultrasound over a time span of at least a few months. However, measurements performed over shorter time spans would yield no useful information—minor signal distortions originating from grain noise and ultrasonic equipment imperfections prevent a meaningful estimate of the minuscule reduction in echo travel time. Using a Model-Based Estimation (MBE) technique, a signal processing scheme has been developed that enables the echo signals from the pipe wall to be separated from the noise. This was implemented in a laboratory experimental program, featuring accelerated erosion/corrosion on the inner wall of a test pipe. The result was a reduction in the uncertainty in the wall thinning rate by a factor of four. This improvement enables a more rapid response by system operators to a change in plant conditions that could pose a pipe integrity problem. It also enables a rapid evaluation of the effectiveness of new corrosion inhibiting agents under plant operating conditions.

  2. Effects of Cations on Corrosion of Inconel 625 in Molten Chloride Salts

    NASA Astrophysics Data System (ADS)

    Zhu, Ming; Ma, Hongfang; Wang, Mingjing; Wang, Zhihua; Sharif, Adel

    2016-04-01

    Hot corrosion of Inconel 625 in sodium chloride, potassium chloride, magnesium chloride, calcium chloride and their mixtures with different compositions is conducted at 900°C to investigate the effects of cations in chloride salts on corrosion behavior of the alloy. XRD, SEM/EDS were used to analyze the compositions, phases, and morphologies of the corrosion products. The results showed that Inconel 625 suffers more severe corrosion in alkaline earth metal chloride molten salts than alkaline metal chloride molten salts. For corrosion in mixture salts, the corrosion rate increased with increasing alkaline earth metal chloride salt content in the mixture. Cations in the chloride molten salts mainly affect the thermal and chemical properties of the salts such as vapor pressure and hydroscopicities, which can affect the basicity of the molten salt. Corrosion of Inconel 625 in alkaline earth metal chloride salts is accelerated with increasing basicity.

  3. Demystifying Controlling Copper Corrosion

    EPA Science Inventory

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  4. Fireside Corrosion USC Steering

    SciTech Connect

    G. R. Holcomb; J. Tylczak

    2011-09-07

    Oxy-Fuel Fireside Research goals are: (1) Determine the effect of oxy-fuel combustion on fireside corrosion - (a) Flue gas recycle choice, Staged combustion ramifications, (c) JCOAL Collaboration; and (2) Develop methods to use chromia solubility in ash as an 'ash corrosivity' measurement - (a) Synthetic ashes at first, then boiler and burner rig ashes, (b) Applicable to SH/RH conditions.

  5. Crude unit corrosion and corrosion control

    SciTech Connect

    Bagdasarian, A.; Feather, J.; Hull, B.; Stephenson, R.; Strong, R.

    1996-08-01

    In the petroleum refining process, the Crude Unit is the initial stage of distillation of the crude oil into useable fractions, either as end products or feed to downstream units. The major pieces of equipment found on units will vary depending on factors such as the assay of the design crude, the age of the refinery, and other downstream units. The unit discussed in this paper has all of the major pieces of equipment found on crude units including double desalting, a preflash section, an atmospheric section, a vacuum section, and a stabilization section. This paper reviews fundamental corrosion issues concerning the Crude Unit process. It is, in concise form, a description of the process and major equipment found in the Crude Unit; types of corrosion and where they occur; corrosion monitoring and inspection advice; and a list of related references for further reading. 12 refs., 1 fig.

  6. COPPER PITTING CORROSION: A CASE STUDY

    EPA Science Inventory

    Localized or pitting corrosion of copper pipes used in household drinking-water plumbing is a problem for many water utilities and their customers. Extreme attack can lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. Water quality has b...

  7. Agricultural Polymers for Corrosion Protection of Metals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion is one of the most serious and challenging problems faced worldwide by industry. When metals come in contact with different environments such as air, water, chemical products and pollutants, they begin to degrade as the metal interacts with its environment. This research investigates the...

  8. A Corrosion Control Manual for Rail Rapid Transit

    NASA Technical Reports Server (NTRS)

    Gilbert, L. O.; Fitzgerald, J. H., III; Menke, J. T.; Lizak, R. M. (Editor)

    1982-01-01

    This manual addresses corrosion problems in the design, contruction, and maintenance of rapid transit systems. Design and maintenance solutions are provided for each problem covered. The scope encompasses all facilities of urban rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. The types of corrosion and their causes as well as rapid transit properties are described. Corrosion control committees, and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual are listed. A bibliography of papers and excerpts of reports is provided and a glossary of frequently used terms is included.

  9. Confronting Twin Paradox Acceleration

    NASA Astrophysics Data System (ADS)

    Murphy, Thomas W.

    2016-05-01

    The resolution to the classic twin paradox in special relativity rests on the asymmetry of acceleration. Yet most students are not exposed to a satisfactory analysis of what exactly happens during the acceleration phase that results in the nonaccelerated observer's more rapid aging. The simple treatment presented here offers both graphical and quantitative solutions to the problem, leading to the correct result that the acceleration-induced age gap is 2Lβ years when the one-way distance L is expressed in light-years and velocity β ≡v/c .

  10. Characterization of corrosion damage in prestressed concrete using acoustic emission

    NASA Astrophysics Data System (ADS)

    Mangual, Jesé; ElBatanouny, Mohamed K.; Vélez, William; Ziehl, Paul; Matta, Fabio; González, Miguel

    2012-04-01

    The corrosion of reinforced concrete structures is a major issue from both a structural safety and maintenance management point of view. Early detection of the internal degradation process provides the owner with sufficient options to develop a plan of action. An accelerated corrosion test was conducted in a small scale concrete specimen reinforced with a 0.5 inch (13 mm) diameter prestressing strand to investigate the correlation between corrosion rate and acoustic emission (AE). Corrosion was accelerated in the laboratory by supplying anodic current via a rectifier while continuously monitoring acoustic emission activity. Results were correlated with traditional electrochemical techniques such as half-cell potential and linear polarization. The location of the active corrosion activity was found through a location algorithm based on time of flight of the stress waves. Intensity analysis was used to plot the relative significance of the damage states present in the specimen and a preliminary grading chart is presented. Results indicate that AE may be a useful non-intrusive technique for the detection and quantification of corrosion damage.

  11. Reducing corrosion in aluminum-steel joints

    SciTech Connect

    Not Available

    1994-01-01

    This article examines how galvanic corrosion in aluminum-intensive steel structures can be controlled, without losing performance, by using transition materials. The topics of the article include the transition material concept, corrosion resistance, experimental conditions, and the results of the experiment including mass loss of lap joints, strength retention, joining methods. The results show how use of steel-clad aluminum transition material in joining aluminum and steel deals successfully addresses the problems of joining and durability associated with increasing use of aluminum on automobiles.

  12. High frequency ultrasonic mitigation of microbial corrosion

    NASA Astrophysics Data System (ADS)

    Almahamedh, Hussain H.; Meegan, G. Douglas; Mishra, Brajendra; Olson, David L.; Spear, John R.

    2012-05-01

    Microbiologically Influenced Corrosion (MIC) is a major problem in oil industry facilities, and considerable effort has been spent to mitigate this costly issue. More environmentally benign methods are under consideration as alternatives to biocides, among which are ultrasonic techniques. In this study, a high frequency ultrasonic technique (HFUT) was used as a mitigation method for MIC. The killing percentages of the HFUT were higher than 99.8 percent and their corrosivity on steel was reduced by more than 50 percent. The practice and result will be discussed.

  13. An Investigation of the Mechanism of IGA/SCC of Alloy 600 in Corrosion Accelerating Heated Crevice Environments: Topical Report - Results for Mod of Heated Crevice - 08/18/1999 - 08/31/2000

    SciTech Connect

    Jesse Lumsden

    2000-11-01

    A pressurized water reactor (PWR) steam generator transfers heat from the primary water, heated in the reactor core, to the secondary coolant system. These are shell and tube heat exchangers having the primary water from the reactor inside the tubes and with steam generation on the shell side. This design generates steam on the OD side of the Alloy 600 (or Alloy 690) steam generator tubes, which leads to the concentration of impurities (referred to as hideout) in occluded regions on the tubes. Of major concern is the crevice formed by the tube/tube support plate (T/TSP) intersection. The restricted mass transport in the small crevice volume prevents the species, which concentrate during the generation of steam on the OD of the tube, from quickly dispersing into the bulk water. The presence of a porous magnetite corrosion product from the support plate and deposits, originating from the feed and condenser systems, in the crevice further restricts mass transport, enhancing the concentrating process. This flow restriction leads to the concentration of impurities from the steam generator water by a thermal hydraulic mechanism.

  14. Corrosion of Tungsten Microelectrodes used in Neural Recording Applications

    PubMed Central

    Patrick, Erin; Orazem, Mark E.; Sanchez, Justin C.; Nishida, Toshikazu

    2011-01-01

    In neuroprosthetic applications, long-term electrode viability is necessary for robust recording of the activity of neural populations used for generating communication and control signals. The corrosion of tungsten microwire electrodes used for intracortical recording applications was analyzed in a controlled bench-top study and compared to the corrosion of tungsten microwires used in an in vivo study. Two electrolytes were investigated for the benchtop electrochemical analysis: 0.9% phosphate buffered saline (PBS) and 0.9% PBS containing 30 mM of hydrogen peroxide. The oxidation and reduction reactions responsible for corrosion were found by measurement of the open circuit potential and analysis of Pourbaix diagrams. Dissolution of tungsten to form the tungstic ion was found to be the corrosion mechanism. The corrosion rate was estimated from the polarization resistance, which was extrapolated from the electrochemical impedance spectroscopy data. The results show that tungsten microwires in an electrolyte of PBS have a corrosion rate of 300–700 µm/yr. The corrosion rate for tungsten microwires in an electrolyte containing PBS and 30 mM H2O2 is accelerated to 10,000–20,000 µm/yr. The corrosion rate was found to be controlled by the concentration of the reacting species in the cathodic reaction (e.g. O2 and H2O2). The in vivo corrosion rate, averaged over the duration of implantation, was estimated to be 100 µm/yr. The reduced in vivo corrosion rate as compared to the benchtop rate is attributed to decreased rate of oxygen diffusion caused by the presence of a biological film and a reduced concentration of available oxygen in the brain. PMID:21470563

  15. Corrosion of tungsten microelectrodes used in neural recording applications.

    PubMed

    Patrick, Erin; Orazem, Mark E; Sanchez, Justin C; Nishida, Toshikazu

    2011-06-15

    In neuroprosthetic applications, long-term electrode viability is necessary for robust recording of the activity of neural populations used for generating communication and control signals. The corrosion of tungsten microwire electrodes used for intracortical recording applications was analyzed in a controlled bench-top study and compared to the corrosion of tungsten microwires used in an in vivo study. Two electrolytes were investigated for the bench-top electrochemical analysis: 0.9% phosphate buffered saline (PBS) and 0.9% PBS containing 30 mM of hydrogen peroxide. The oxidation and reduction reactions responsible for corrosion were found by measurement of the open circuit potential and analysis of Pourbaix diagrams. Dissolution of tungsten to form the tungstic ion was found to be the corrosion mechanism. The corrosion rate was estimated from the polarization resistance, which was extrapolated from the electrochemical impedance spectroscopy data. The results show that tungsten microwires in an electrolyte of PBS have a corrosion rate of 300-700 μm/yr. The corrosion rate for tungsten microwires in an electrolyte containing PBS and 30 mM H₂O₂ is accelerated to 10,000-20,000 μm/yr. The corrosion rate was found to be controlled by the concentration of the reacting species in the cathodic reaction (e.g. O₂ and H₂O₂). The in vivo corrosion rate, averaged over the duration of implantation, was estimated to be 100 μm/yr. The reduced in vivo corrosion rate as compared to the bench-top rate is attributed to decreased rate of oxygen diffusion caused by the presence of a biological film and a reduced concentration of available oxygen in the brain. PMID:21470563

  16. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

    Discusses general corrosion reactions (iron to rust), including corrosion of iron, sulfur dioxide, chlorides, immersed corrosion, and underground corrosion. Also discusses corrosion inhibition, including corrosion inhibitors (anodic, cathodic, mixed, organic); safe/dangerous inhibitors; and corrosion/inhibition in concrete/marble, showcases/boxes,…

  17. Advanced Accelerator Applications University Participation Program

    SciTech Connect

    Y. Chen; A. Hechanova

    2007-07-25

    Our research tasks span the range of technology areas for transmutation, gas-cooled reactor technology, and high temperature heat exchangers, including separation of actinides from spent nuclear fuel, methods of fuel fabrication, reactor-accelerator coupled experiments, corrosion of materials exposed to lead-bismuth eutectic, and special nuclear materials protection and accountability.

  18. Corrosion-resistant uranium

    DOEpatents

    Hovis, Jr., Victor M.; Pullen, William C.; Kollie, Thomas G.; Bell, Richard T.

    1983-01-01

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  19. Corrosion-resistant uranium

    SciTech Connect

    Bell, R.T.; Hovis, V.M.; Kollie, T.G.; Pullen, W.C.

    1983-05-31

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  20. Microbiologically influenced corrosion testing

    SciTech Connect

    Kearns, J.R.; Little, B.J.

    1994-01-01

    This symposium was held November 16--17, 1992 in Miami, Florida. The purpose of the symposium was to provide a forum for state-of-the-art information on the effects of microorganisms on the corrosion of metals. Many industrial needs in the area of microbial influenced corrosion testing are identified in the presentations along with latest laboratory and field testing techniques. Strategies to monitor and control corrosion and biofouling in water distribution systems, underground pipelines, buildings, and marine vessels are discussed. Individual papers have been processed separately for inclusion in the appropriate data bases.

  1. Irritants and corrosives.

    PubMed

    Tovar, Richard; Leikin, Jerrold B

    2015-02-01

    This article reviews toxic chemicals that cause irritation and damage to single and multiple organ systems (corrosion) in an acute fashion. An irritant toxic chemical causes reversible damage to skin or other organ system, whereas a corrosive agent produces irreversible damage, namely, visible necrosis into integumentary layers, following application of a substance for up to 4 hours. Corrosive reactions can cause coagulation or liquefaction necrosis. Damaged areas are typified by ulcers, bleeding, bloody scabs, and eventual discoloration caused by blanching of the skin, complete areas of alopecia, and scars. Histopathology should be considered to evaluate questionable lesions. PMID:25455665

  2. Corrosion-resistant uranium

    DOEpatents

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  3. Review of critical factors affecting crude corrosivity

    SciTech Connect

    Tebbal, S.; Kane, R.D.

    1996-08-01

    Lower quality opportunity crudes are now processed in most refineries and the source of the crudes may vary daily. These feedstocks, if not properly handled, can result in reduction in service life of equipment as well as costly failure and downtime. Analytical tools are needed to predict their high temperature corrosivity toward distillation units. Threshold in total sulfur and total acid number (TAN) have been used for many years as rules of thumb for predicting crude corrosivity, However, it is now realized that they are not accurate in their predictive ability. Crudes with similar composition and comparable with respect to process considerations have been found to be entirely different in their impact on corrosion. Naphthenic acid content, sulfur content, velocity, temperature, and materials of construction are the main factors affecting the corrosion process, Despite progress made in elucidating the role of the different parameters on the crude corrosivity process, the main problem is in calculating their combined effect, especially when the corroding stream is such a complex mixture. The TAN is usually related directly to naphthenic acid content. However, discrepancies between analytical methods and interference of numerous components of the crude itself lead to unreliable reported content of naphthenic acid. The sulfur compounds, with respect to corrosivity, appear to relate more to their decomposition at elevated temperature to form hydrogen sulfide than to their total content in crude. This paper reviews the present situation regarding crude corrosivity in distillation units, with the aim of indicating the extent of available information, and areas where further research is necessary.

  4. Research needs for corrosion control and prevention in energy conservation systems

    SciTech Connect

    Brooman, E.W.; Hurwitch, J.W.

    1985-06-01

    A group of 28 electrochemists, materials scientists and corrosion engineers was brought together to determine if the government could have a role as a focal point for corrosion R and D, discuss opportunities in fundamental research and solving corrosion problems, and develop a research agenda. Participants from government, industry and academia assembled into four technical discussion groups: localized corrosion, general corrosion, high temperature corrosion, and corrosion control and prevention. Research needs were identified, discussed, then assigned a figure of merit. Some 44 corrosion control and prevention topics were identified as having a high priority for consideration for funding. Another 35 topics were identified as having a medium priority for funding. When classified according to corrosion phenomenon, the areas which should receive the most attention are molten salt attack, crevice corrosion, stress-corrosion cracking, erosion-corrosion, pitting attack, intergranular attack and corrosion fatigue. When classified according to the sector or system involved, those which should receive the most attention are chemical processes, transportation, buildings and structures, electric power generation, and batteries and fuel cells.

  5. Protect nuclear plant fasteners from boric acid corrosion

    SciTech Connect

    Moisidis, N.; Popescu, M.; Ratiu, M. )

    1992-03-01

    Boric acid corrosion of pump and valve fasteners in pressurized water reactor (PWR) power plants can be prevented by implementing appropriate fastener steel replacement and extended inspections to detect and correct the cause of leakage. In this paper a three-phase corrosion protection program based on system operability, outage-related accessibility, and cost of fastener replacement versus maintenance frequency increase is presented. A selection criteria for fastener material is also presented. Degradation or failure of pressure retaining fasteners at pumps and valves has been reported in several areas exposed to leakage of closures in long-term service. The resulting boric acid corrosion experienced in PWR systems is defined as an accelerated process produced when water evaporates from leaking coolant. The primary detrimental effect of boric acid leakage is wastage (or general dissolution corrosion) of low-alloy carbon steel fasteners.

  6. Steel reinforcement corrosion detection with coaxial cable sensors

    NASA Astrophysics Data System (ADS)

    Muchaidze, Iana; Pommerenke, David; Chen, Genda

    2011-04-01

    Corrosion processes in the steel reinforced structures can result in structural deficiency and with time create a threat to human lives. Millions of dollars are lost each year because of corrosion. According to the U. S. Federal Highway Administration (FHWA) the average annual cost of corrosion in the infrastructure sector by the end of 2002 was estimated to be $22.6 billion. Timely remediation/retrofit and effective maintenance can extend the structure's live span for much less expense. Thus the considerable effort should be done to deploy corrosion monitoring techniques to have realistic information on the location and the severity of damage. Nowadays commercially available techniques for corrosion monitoring require costly equipment and certain interpretational skills. In addition, none of them is designed for the real time quality assessment. In this study the crack sensor developed at Missouri University of Science and Technology is proposed as a distributed sensor for real time corrosion monitoring. Implementation of this technology may ease the pressure on the bridge owners restrained with the federal budget by allowing the timely remediation with the minimal financial and labor expenses. The sensor is instrumented in such a way that the location of any discontinuity developed along its length can be easily detected. When the sensor is placed in immediate vicinity to the steel reinforcement it is subjected to the same chemical process as the steel reinforcement. And corrosion pitting is expected to develop on the sensor exactly at the same location as in the rebar. Thus it is expected to be an effective tool for active corrosion zones detection within reinforced concrete (RC) members. A series of laboratory tests were conducted to validate the effectiveness of the proposed methodology. Nine sensors were manufactured and placed in the artificially created corrosive environment and observed over the time. To induce accelerated corrosion 3% and 5% Na

  7. Characterization of Encapsulated Corrosion Inhibitors Containing Microparticles for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

    This poster presents the results obtained from experiments designed to evaluate the release properties, as well as the corrosion inhibition effectiveness, of several encapsulated corrosion inhibitors. Microencapsulation has been used in the development of environmentally friendly multifunctional smart coatings. This technique enables the incorporation of autonomous corrosion detection, inhibition and self-healing functionalities into many commercially available coating systems. Select environmentally friendly corrosion inhibitors were encapsulated in organic and inorganic pH-sensitive microparticles and their release in basic solutions was studied. The release rate results showed that the encapsulation can be tailored from fast, for immediate corrosion protection, to slow, which will provide continued long-term corrosion protection. The incorporation of several corrosion inhibitor release profiles into a coating provides effective corrosion protection properties. To investigate the corrosion inhibition efficiency of the encapsulated inhibitors, electrochemical techniques were used to obtain corrosion potential, polarization curve and polarization resistance data. These measurements were performed using the free as well as the encapsulated inhibitors singly or in combinations. Results from these electrochemical tests will be compared to those obtained from weight loss and other accelerated corrosion experiments.

  8. Comparison of Stress Corrosion Cracking Susceptibility of Laser Machined and Milled 304 L Stainless Steel

    NASA Astrophysics Data System (ADS)

    Gupta, R. K.; Kumar, Aniruddha; Nagpure, D. C.; Rai, S. K.; Singh, M. K.; Khooha, Ajay; Singh, A. K.; Singh, Amrendra; Tiwari, M. K.; Ganesh, P.; Kaul, R.; Singh, B.

    2016-07-01

    Machining of austenitic stainless steel components is known to introduce significant enhancement in their susceptibility to stress corrosion cracking. The paper compares stress corrosion cracking susceptibility of laser machined 304 L stainless steel specimens with conventionally milled counterpart in chloride environment. With respect to conventionally milled specimens, laser machined specimens displayed more than 12 times longer crack initiation time in accelerated stress corrosion cracking test in boiling magnesium chloride as per ASTM G36. Reduced stress corrosion cracking susceptibility of laser machined surface is attributed to its predominantly ferritic duplex microstructure in which anodic ferrite phase was under compressive stress with respect to cathodic austenite.

  9. Fracture of concrete caused by the reinforcement corrosion products

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. T.; Millard, A.; Caré, S.; L'Hostis, V.; Berthaud, Y.

    2006-11-01

    One of the most current degradations in reinforced concrete structures is related to the corrosion of the reinforcements. The corrosion products during active corrosion induce a mechanical pressure on the surrounding concrete that leads to cover cracking along the rebar. The objective of this work is to study the cracking of concrete due to the corrosion of the reinforcements. The phenomenon of corrosion/cracking is studied in experiments through tests of accelerated corrosion on plate and cylindrical specimens. A CCD camera is used to take images every hour and the pictures are analyzed by using the intercorrelation image technique (Correli^LMT) to derive the displacement and strain field. Thus the date of appearance of the first through crack is detected and the cinematic crack initiations are observed during the test. A finite element model that allows prediction of the mechanical consequences of the corrosion of steel in reinforced concrete structures is proposed. From the comparison between the test results and numerical simulations, it may be concluded that the model is validated in term of strains up to the moment when the crack becomes visible, and in terms of crack pattern.

  10. A Monitoring Method Based on FBG for Concrete Corrosion Cracking

    PubMed Central

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  11. A Monitoring Method Based on FBG for Concrete Corrosion Cracking.

    PubMed

    Mao, Jianghong; Xu, Fangyuan; Gao, Qian; Liu, Shenglin; Jin, Weiliang; Xu, Yidong

    2016-01-01

    Corrosion cracking of reinforced concrete caused by chloride salt is one of the main determinants of structure durability. Monitoring the entire process of concrete corrosion cracking is critical for assessing the remaining life of the structure and determining if maintenance is needed. Fiber Bragg Grating (FBG) sensing technology is extensively developed in photoelectric monitoring technology and has been used on many projects. FBG can detect the quasi-distribution of strain and temperature under corrosive environments, and thus it is suitable for monitoring reinforced concrete cracking. According to the mechanical principle that corrosion expansion is responsible for the reinforced concrete cracking, a package design of reinforced concrete cracking sensors based on FBG was proposed and investigated in this study. The corresponding relationship between the grating wavelength and strain was calibrated by an equal strength beam test. The effectiveness of the proposed method was verified by an electrically accelerated corrosion experiment. The fiber grating sensing technology was able to track the corrosion expansion and corrosion cracking in real time and provided data to inform decision-making for the maintenance and management of the engineering structure. PMID:27428972

  12. Acoustic emission intensity analysis of corrosion in prestressed concrete piles

    NASA Astrophysics Data System (ADS)

    Vélez, William; Matta, Fabio; Ziehl, Paul

    2014-02-01

    Corrosion of steel strands in prestressed concrete (PC) bridges may lead to substantial damage or collapse well before the end of the design life. Acoustic Emission (AE) is a suitable nondestructive technique to detect and locate corrosion in reinforced and prestressed concrete, which is key to prioritize inspection and maintenance. An effective tool to analyze damage-related AE data is intensity analysis (IA), which is based on two data trends, namely Severity (average signal strength of high amplitude hits) and Historic Index (ratio of the average signal strength of the most recent hits to the average of all hits). IA criteria for corrosion assessment in PC were recently proposed based on empirical evidence from accelerated corrosion tests. In this paper, AE data from prestressed and non-prestressed concrete pile specimens exposed to salt water wet-dry cycling for over 600 days are used to analyze the relation between Severity and Historic Index and actual corrosion. Evidence of corrosion is gained from the inspection of decommissioned specimens. The selection of suitable J and K parameters for IA is discussed, and an IA chart with updated corrosion criteria for PC piles is presented.

  13. Corrosion and arc erosion in MHD channels

    NASA Astrophysics Data System (ADS)

    Rosa, R. J.; Pollina, R. J.

    1992-08-01

    The problems connected with gas side corrosion for the design of the 1A4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. The results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  14. Corrosion and arc erosion in MHD channels

    SciTech Connect

    Rosa, R.J. . Dept. of Mechanical Engineering); Pollina, R.J. . Dept. of Mechanical Engineering EG and G Energy Measurements, Inc., Las Vegas, NV )

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  15. Hot corrosion of ceramic engine materials

    NASA Technical Reports Server (NTRS)

    Fox, Dennis S.; Jacobson, Nathan S.; Smialek, James L.

    1988-01-01

    A number of commercially available SiC and Si3N4 materials were exposed to 1000 C in a high velocity, pressurized burner rig as a simulation of a turbine engine environment. Sodium impurities added to the burner flame resulted in molten Na2SO4 deposition, attack of the SiC and Si4N4 and formation of substantial Na2O-x(SiO2) corrosion product. Room temperature strength of the materials decreased. This was a result of the formation of corrosion pits in SiC, and grain boundary dissolution and pitting in Si3N4. Corrosion regimes for such Si-based ceramics have been predicted using thermodynamics and verified in rig tests of SiO2 coupons. Protective mullite coatings are being investigated as a solution to the corrosion problem for SiC and Si3N4. Limited corrosion occurred to cordierite (Mg2Al4Si5O18) but some cracking of the substrate occurred.

  16. Corrosion of 90-10 Cupronickel Alloys in Seawater Systems

    NASA Astrophysics Data System (ADS)

    Frick, J. P.; Scharfstein, L. R.; Parrill, T. M.; Haaland, G.

    1985-03-01

    This paper documents the presence of a detrimental iron based grain boundary phase that develops during extended time at sensitizing temperature. This defect has been responsible for premature failure. Standard electrochemical testing techniques fail to predict accelerated corrosion rates that are due to galvanic coupling within the material.

  17. Corrosion of a-Si cells and modules

    NASA Technical Reports Server (NTRS)

    Mon, G. R.; Wen, L.; Ross, R. G., Jr.

    1987-01-01

    The authors report on corrosion/erosion phonemena observed in exposing a-Si cells, modules, and specially designed test structures to natural and accelerated test environments. Relevant cell and module I-V curve data used for monitoring degradation are presented. The causes of the observed degradation, methods of mitigation, and consequences for fielded modules are discussed.

  18. Corrosion Inhibitors for Aluminum.

    ERIC Educational Resources Information Center

    Muller, Bodo

    1995-01-01

    Describes a simple and reliable test method used to investigate the corrosion-inhibiting effects of various chelating agents on aluminum pigments in aqueous alkaline media. The experiments that are presented require no complicated or expensive electronic equipment. (DDR)

  19. Effect of Waterproofing Admixtures on the Flexural Strength and Corrosion Resistance of Concrete

    NASA Astrophysics Data System (ADS)

    Geetha, A.; Perumal, P.

    2012-02-01

    This paper deals about the flexural strength and corrosion behaviour of concrete using waterproofing admixtures. The effect of waterproofing admixtures on the corrosion behaviour of RCC specimen has been studied by conducting accelerated corrosion test. To identify the effect of corrosion in pull out strength, corrosion process was induced by means of accelerated corrosion procedure. To accelerate the reinforcement corrosion, direct electric current was impressed on the rebar embedded in the specimen using a DC power supply system that has a facility to adjust voltage. The addition of waterproofing admixtures also shows the improvement in the flexural strength of concrete has been studied by conducting flexural strength tests on the concrete prism specimen of size 100 × 100 × 500 mm with and without admixtures for various dosages and various curing periods of 7 and 28 days. The results showed that the presence of waterproofing admixtures always improves the corrosion resistance and thus increases the strength of concrete due to the hydrophobic action of waterproofing admixtures.

  20. Corrosion science and technology

    SciTech Connect

    Talbot, D.; Talbot, J.

    1998-01-01

    This book investigates the chemical, electrochemical, and metallurgical aspects of corrosion control in contemporary technologies. By examining the structures of water, oxides, and metals, the text identifies the interactions in which metals corrode in natural and artificial environments. The book also includes profiles of technological use in aviation, automobile manufacturing, food processing, and building construction; explanations of scientific principles, real world applications, and case histories; and extensive references for corrosion-related literature and other information.

  1. Method for inhibiting corrosion

    SciTech Connect

    Wu, Y.; Stapp, P. R.

    1985-12-03

    A composition comprising the reaction adduct or neutralized product resulting from the reaction of a maleic anhydride and an oil containing a polynuclear aromatic compound is provided which, when applied to a metal surface, forms a corrosion-inhibiting film thereon. The composition is particularly useful in the treatment of down-hole metal surfaces in oil and gas wells to inhibit the corrosion of the metal.

  2. Corrosivity Of Pyrolysis Oils

    SciTech Connect

    Keiser, James R; Bestor, Michael A; Lewis Sr, Samuel Arthur; Storey, John Morse

    2011-01-01

    Pyrolysis oils from several sources have been analyzed and used in corrosion studies which have consisted of exposing corrosion coupons and stress corrosion cracking U-bend samples. The chemical analyses have identified the carboxylic acid compounds as well as the other organic components which are primarily aromatic hydrocarbons. The corrosion studies have shown that raw pyrolysis oil is very corrosive to carbon steel and other alloys with relatively low chromium content. Stress corrosion cracking samples of carbon steel and several low alloy steels developed through-wall cracks after a few hundred hours of exposure at 50 C. Thermochemical processing of biomass can produce solid, liquid and/or gaseous products depending on the temperature and exposure time used for processing. The liquid product, known as pyrolysis oil or bio-oil, as produced contains a significant amount of oxygen, primarily as components of water, carboxylic acids, phenols, ketones and aldehydes. As a result of these constituents, these oils are generally quite acidic with a Total Acid Number (TAN) that can be around 100. Because of this acidity, bio-oil is reported to be corrosive to many common structural materials. Despite this corrosive nature, these oils have the potential to replace some imported petroleum. If the more acidic components can be removed from this bio-oil, it is expected that the oil could be blended with crude oil and then processed in existing petroleum refineries. The refinery products could be transported using customary routes - pipelines, barges, tanker trucks and rail cars - without a need for modification of existing hardware or construction of new infrastructure components - a feature not shared by ethanol.

  3. Corrosion resistant filter unit

    SciTech Connect

    Gentry, J.M.

    1992-02-18

    This patent describes a fluid filter assembly adapted for the filtration of corrosive fluid to be injected into a well bore at pressure levels which may exceed 10,000 pounds per square. It comprises: a frame assembly for the mounting of a portion of the fluid filter assembly therein, the frame assembly; filter pods, the plurality of filter pods forming at least two banks of filter pods, each bank having at least two filter pods therein, each bank of the filter pods being supported by one or more the supports of the plurality of supports secured to selected struts of the frame assembly; an inlet manifold to direct the corrosive fluid to the plurality of filter pods, the inlet manifold being interconnected to the banks of filter pods formed by the filter pods whereby flow of the corrosive fluid can be directed to each bank of the filter pods; an outlet manifold to direct the corrosive fluid from the filter pods, the outlet manifold being interconnected to the banks of filter pods formed by the filter pods; a first valve means to control the flow of the corrosive fluid between banks of filter pods formed by the filter pods whereby the flow of the corrosive fluid can be selectively directed to each bank of the filter pods; a second valve means to selectively control the flow of the corrosive fluid between the inlet manifold and the outlet manifold; and union means for interconnecting the filter pods, inlet manifold and outlet manifold, each of the union means including mechanical connection means and internal seal means for isolating the corrosive fluids from the mechanical connection means.

  4. Examination of Corrosion Products and the Alloy Surface After Crevice Corrosion of a Ni-Cr-Mo- Alloy

    SciTech Connect

    X. Shan; J.H. Payer

    2006-06-09

    The objective of this study is to investigate the composition of corrosion products and the metal surface within a crevice after localized corrosion. The analysis provides insight into the propagation, stifling and arrest processes for crevice corrosion and is part of a program to analyze the evolution of localized corrosion damage over long periods of time, i.e. 10,000 years and longer. The approach is to force the initiation of crevice corrosion by applying anodic polarization to a multiple crevice assembly (MCA). Results are reported here for alloy C-22, a Ni-Cr-Mo alloy, exposed to a high temperature, concentrated chloride solution. Controlled crevice corrosion tests were performed on C-22 under highly aggressive, accelerated condition, i.e. 4M NaCl, 100 C and anodic polarization to -0.15V-SCE. The crevice contacts were by either a polymer tape (PTFE) compressed by a ceramic former or by a polymer (PTFE) crevice former. Figure 1 shows the polarization current during a crevice corrosion test. After an incubation period, several initiation-stifle-arrest events were indicated. The low current at the end of the test indicated that the metal surface had repassivated.

  5. The problems associated with the monitoring of complex workplace radiation fields at European high-energy accelerators and thermonuclear fusion facilities.

    PubMed

    Bilski, P; Blomgren, J; d'Errico, F; Esposito, A; Fehrenbacher, G; Fernàndez, F; Fuchs, A; Golnik, N; Lacoste, V; Leuschner, A; Sandri, S; Silari, M; Spurny, F; Wiegel, B; Wright, P

    2007-01-01

    The European Commission is funding within its Sixth Framework Programme a three-year project (2005-2007) called CONRAD, COordinated Network for RAdiation Dosimetry. The organisational framework for this project is provided by the European Radiation Dosimetry Group EURADOS. One task within the CONRAD project, Work Package 6 (WP6), was to provide a report outlining research needs and research activities within Europe to develop new and improved methods and techniques for the characterisation of complex radiation fields at workplaces around high-energy accelerators, but also at the next generation of thermonuclear fusion facilities. The paper provides an overview of the report, which will be available as CERN Yellow Report. PMID:17496292

  6. Corrosion Embrittlement of Duralumin V : Results of Weather-Exposure Tests

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1929-01-01

    In a series of weather exposure tests of sheet duralumin, upon which accelerated corrosion tests in the laboratory by the wet-and-dry corrosion method in a sodium chloride solution has already been carried out, a close parallelism between the results of the two kinds of tests was found to exist. The exposure tests showed that the lack of permanence of sheet duralumin is largely, if not entirely, due to corrosion. A corrosion attack of an intercrystalline nature is very largely responsible for the degree of embrittlement produced. The rate of embrittlement was greatly accelerated by a marine atmosphere and by the tropical climate. Variations in corrosion and embrittlement are noted in relation to heat treatment, cold working, and types of protective coatings.

  7. Plasma-Sprayed Ceramic Coatings for Barrier Applications Against Molten Uranium Corrosion

    NASA Astrophysics Data System (ADS)

    Ananthapadmanabhan, P. V.; Chakravarthy, Y.; Chaturvedi, Vandana; Thiyagarajan, T. K.; Pragatheeswaran, A.

    2015-07-01

    Ceramic coatings are applied on engineering components for protecting them from large thermal load and hot corrosion. Choices of coating material for protection against hot corrosion by uranium are few, because of its high reactivity. Yttrium oxide has a high melting temperature and is inert towards uranium. Therefore, yttrium oxide coatings are effective as a barrier against hot corrosion by uranium and its alloys. This paper gives a summary of the developmental work on plasma-sprayed yttria coatings for corrosion barrier applications against molten uranium. Results show that plasma-sprayed yttria coatings offer a long-term solution to hot corrosion problems.

  8. Inhibition of steel corrosion by thiourea derivatives

    SciTech Connect

    Singh, I. )

    1993-06-01

    The thiourea group of sulfur compounds has important theoretical and practical applications. Thioureas have been studied extensively, but their inhibition mechanism is not fully understood. The effect of thiourea; allylthiourea; N,N[prime]-diethylthiourea; N,N[prime]-di-isopropylthiourea; phenylthiourea; thiocarbanilide; and symdiotolylthiourea on the corrosion reaction and on the amount of H[sub 2] absorbed by cold-rolled mild steel in 1 N H[sub 2]SO[sub 4] at 40 C was studied. Inhibitor efficiency increased with increases in molecular weight and inhibitor concentration. Higher inhibitor concentrations decreased H[sub 2] pickup. Thiourea accelerated corrosion reactions and H[sub 2] pickup at higher concentrations. Potential studies showed cathodic reactions were inhibited at lower concentrations and anodic reactions were inhibited at higher concentrations. Results were based on the adsorption theory, and all inhibitors studied followed the Langmuir isotherm.

  9. Superheater Corrosion In Biomass Boilers: Today's Science and Technology

    SciTech Connect

    Sharp, William

    2011-12-01

    This report broadens a previous review of published literature on corrosion of recovery boiler superheater tube materials to consider the performance of candidate materials at temperatures near the deposit melting temperature in advanced boilers firing coal, wood-based fuels, and waste materials as well as in gas turbine environments. Discussions of corrosion mechanisms focus on the reactions in fly ash deposits and combustion gases that can give corrosive materials access to the surface of a superheater tube. Setting the steam temperature of a biomass boiler is a compromise between wasting fuel energy, risking pluggage that will shut the unit down, and creating conditions that will cause rapid corrosion on the superheater tubes and replacement expenses. The most important corrosive species in biomass superheater corrosion are chlorine compounds and the most corrosion resistant alloys are typically FeCrNi alloys containing 20-28% Cr. Although most of these materials contain many other additional additions, there is no coherent theory of the alloying required to resist the combination of high temperature salt deposits and flue gases that are found in biomass boiler superheaters that may cause degradation of superheater tubes. After depletion of chromium by chromate formation or chromic acid volatilization exceeds a critical amount, the protective scale gives way to a thick layer of Fe{sub 2}O{sub 3} over an unprotective (FeCrNi){sub 3}O{sub 4} spinel. This oxide is not protective and can be penetrated by chlorine species that cause further acceleration of the corrosion rate by a mechanism called active oxidation. Active oxidation, cited as the cause of most biomass superheater corrosion under chloride ash deposits, does not occur in the absence of these alkali salts when the chloride is present as HCl gas. Although a deposit is more corrosive at temperatures where it is molten than at temperatures where it is frozen, increasing superheater tube temperatures through

  10. Accelerated Reader.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO.

    This paper provides an overview of Accelerated Reader, a system of computerized testing and record-keeping that supplements the regular classroom reading program. Accelerated Reader's primary goal is to increase literature-based reading practice. The program offers a computer-aided reading comprehension and management program intended to motivate…

  11. Deflation-accelerated preconditioning of the Poisson-Neumann Schur problem on long domains with a high-order discontinuous element-based collocation method

    NASA Astrophysics Data System (ADS)

    Joshi, Sumedh M.; Thomsen, Greg N.; Diamessis, Peter J.

    2016-05-01

    A combination of block-Jacobi and deflation preconditioning is used to solve a high-order discontinuous element-based collocation discretization of the Schur complement of the Poisson-Neumann system as arises in the operator splitting of the incompressible Navier-Stokes equations. The preconditioners and deflation vectors are chosen to mitigate the effects of ill-conditioning due to highly-elongated domains typical of simulations of strongly non-hydrostatic environmental flows, and to achieve Generalized Minimum RESidual method (GMRES) convergence independent of the size of the number of elements in the long direction. The ill-posedness of the Poisson-Neumann system manifests as an inconsistency of the Schur complement problem, but it is shown that this can be accounted for with appropriate projections out of the null space of the Schur complement matrix without affecting the accuracy of the solution. The block-Jacobi preconditioner is shown to yield GMRES convergence independent of the polynomial order and only weakly dependent on the number of elements within a subdomain in the decomposition. The combined deflation and block-Jacobi preconditioning is compared with two-level non-overlapping block-Jacobi preconditioning of the Schur problem, and while both methods achieve convergence independent of the grid size, deflation is shown to require half as many GMRES iterations and 25% less wall-clock time for a variety of grid sizes and domain aspect ratios. The deflation methods shown to be effective for the two-dimensional Poisson-Neumann problem are extensible to the three-dimensional problem assuming a Fourier discretization in the third dimension. A Fourier discretization results in a two-dimensional Helmholtz problem for each Fourier component that is solved using deflated block-Jacobi preconditioning on its Schur complement. Here again deflation is shown to be superior to two-level non-overlapping block-Jacobi preconditioning, requiring about half as many GMRES

  12. Correlation of steel corrosion in pipe flow with jet impingement and rotating cylinder tests

    SciTech Connect

    Efird, K.D.; Wright, E.J.; Boros, J.A.; Hailey, T.G.

    1993-12-01

    The relationship of laboratory fluid flow corrosion test techniques to flow-accelerated corrosion in field applications and the parameters required to apply laboratory data effectively in the field were studied. Single-phase, aqueous, sweet corrosion of steel in turbulent pipe flow was correlated to corrosion in jet impingement and rotating cylinder tests. All tests were conducted simultaneously, using the same test fluid to minimize environmental variables and to allow a direct, realistic comparison of test methods. Rotating cylinder electrode corrosion rates did not correlate with pipe flow based on wall shear stress or mass transfer for flow-accelerated corrosion of carbon (C) steel in the environment studied. Jet impingement corrosion rates for the test ring at r/r{sub 0} = 3 correlated with pipe flow based on wall shear stress. The general equation for flow-accelerated corrosion of C steel under turbulent flow conditions in this environment was expressed as: R = a{tau}{sub w}{sup b} where R was the C steel corrosion rate in mm/y and {tau}{sub w} was the wall shear stress in N/m{sup 2}. Effects of solution chemistry were contained in the equation coefficient and exponent and require further experimental definition. The physical fluid and hydrodynamic parameters were included in {tau}{sub w}. Use of wall shear stress as the correlating factor did not imply a shear mechanism for corrosion acceleration. Wall shear stress was found to be a hydrodynamic factor that can be used effectively to relate fluid flow in different geometries, allowing valid comparison of laboratory tests and field operations.

  13. Treatment Prevents Corrosion in Steel and Concrete Structures

    NASA Technical Reports Server (NTRS)

    2007-01-01

    In the mid-1990s, to protect rebar from corrosion, NASA developed an electromigration technique that sends corrosion-inhibiting ions into rebar to prevent rust, corrosion, and separation from the surrounding concrete. Kennedy Space Center worked with Surtreat Holding LLC, of Pittsburgh, Pennsylvania, a company that had developed a chemical option to fight structural corrosion, combining Surtreat's TPS-II anti-corrosive solution and electromigration. Kennedy's materials scientists reviewed the applicability of the chemical treatment to the electromigration process and determined that it was an effective and environmentally friendly match. Ten years later, NASA is still using this approach to fight concrete corrosion, and it has also developed a new technology that will further advance these efforts-a liquid galvanic coating applied to the outer surface of reinforced concrete to protect the embedded rebar from corrosion. Surtreat licensed this new coating technology and put it to use at the U.S. Army Naha Port, in Okinawa, Japan. The new coating prevents corrosion of steel in concrete in several applications, including highway and bridge infrastructures, piers and docks, concrete balconies and ceilings, parking garages, cooling towers, and pipelines. A natural compliment to the new coating, Surtreat's Total Performance System provides diagnostic testing and site analysis to identify the scope of problems for each project, manufactures and prescribes site-specific solutions, controls material application, and verifies performance through follow-up testing and analysis.

  14. Use of an acoustic borehole televiewer to investigate casing corrosion in geothermal wells

    SciTech Connect

    Carson, C.C.; Bauman, T.

    1986-03-01

    Corrosion of well and surface equipment due to the presence of hot, corrosive brines is one of the major problems facing geothermal operators. For wellbore casing, this problem is complicated by the fact that in-place inspection is difficult at best. In an attempt to improve this situation, a prototype acoustic borehole televiewer designed to operate in geothermal wells was used to study the corrosion damage to casing in three commercial wells. The results of this experiment were promising. The televiewer returns helped to define areas of major corrosion damage and to indicate the extent of the damage. This paper briefly discusses the corrosion problem, describes the acoustic borehole televiewer, and then summarizes the results of the field test of the televiewer's capability for investigating corrosion.

  15. FPGA Verification Accelerator (FVAX)

    NASA Technical Reports Server (NTRS)

    Oh, Jane; Burke, Gary

    2008-01-01

    Is Verification Acceleration Possible? - Increasing the visibility of the internal nodes of the FPGA results in much faster debug time - Forcing internal signals directly allows a problem condition to be setup very quickly center dot Is this all? - No, this is part of a comprehensive effort to improve the JPL FPGA design and V&V process.

  16. Modeling pore corrosion in normally open gold- plated copper connectors.

    SciTech Connect

    Battaile, Corbett Chandler; Moffat, Harry K.; Sun, Amy Cha-Tien; Enos, David George; Serna, Lysle M.; Sorensen, Neil Robert

    2008-09-01

    The goal of this study is to model the electrical response of gold plated copper electrical contacts exposed to a mixed flowing gas stream consisting of air containing 10 ppb H{sub 2}S at 30 C and a relative humidity of 70%. This environment accelerates the attack normally observed in a light industrial environment (essentially a simplified version of the Battelle Class 2 environment). Corrosion rates were quantified by measuring the corrosion site density, size distribution, and the macroscopic electrical resistance of the aged surface as a function of exposure time. A pore corrosion numerical model was used to predict both the growth of copper sulfide corrosion product which blooms through defects in the gold layer and the resulting electrical contact resistance of the aged surface. Assumptions about the distribution of defects in the noble metal plating and the mechanism for how corrosion blooms affect electrical contact resistance were needed to complete the numerical model. Comparisons are made to the experimentally observed number density of corrosion sites, the size distribution of corrosion product blooms, and the cumulative probability distribution of the electrical contact resistance. Experimentally, the bloom site density increases as a function of time, whereas the bloom size distribution remains relatively independent of time. These two effects are included in the numerical model by adding a corrosion initiation probability proportional to the surface area along with a probability for bloom-growth extinction proportional to the corrosion product bloom volume. The cumulative probability distribution of electrical resistance becomes skewed as exposure time increases. While the electrical contact resistance increases as a function of time for a fraction of the bloom population, the median value remains relatively unchanged. In order to model this behavior, the resistance calculated for large blooms has been weighted more heavily.

  17. Pore corrosion model for gold-plated copper contacts.

    SciTech Connect

    Moffat, Harry K.; Sun, Amy Cha-Tien; Glauner, Carly S.; Enos, David George

    2005-04-01

    The goal of this study is to model the electrical response of gold plated copper electrical contacts exposed to a mixed flowing gas stream consisting of air containing 10ppb H2S at 30 C and a relative humidity of 70%. This environment accelerates the attack normally observed in a light industrial environment (essentially a simplified version of the Battelle class 2 environment). Corrosion rates were quantified by measuring the corrosion site density, size distribution, and the macroscopic electrical resistance of the aged surface as a function of exposure time. A pore corrosion numerical model was used to predict both the growth of copper sulfide corrosion product which blooms through defects in the gold layer and the resulting electrical contact resistance of the aged surface. Assumptions about the distribution of defects in the noble metal plating and the mechanism for how corrosion blooms affect electrical contact resistance were needed to close the numerical model. Comparisons are made to the experimentally observed number density of corrosion sites, the size distribution of corrosion product blooms, and the cumulative probability distribution of the electrical contact resistance. Experimentally, the bloom site density increases as a function of time, whereas the bloom size distribution remains relatively independent of time. These two effects are included in the numerical model by adding a corrosion initiation probability proportional to the surface area along with a probability for bloom-growth extinction proportional to the corrosion product bloom volume. The cumulative probability distribution of electrical resistance becomes skewed as exposure time increases. While the electrical contact resistance increases as a function of time for a fraction of the bloom population, the median value remains relatively unchanged. In order to model this behavior, the resistance calculated for large blooms has been weighted more heavily.

  18. Use this ``tool box`` to detect corrosion through insulation

    SciTech Connect

    Carriveau, G.W.

    1997-09-01

    There is a need for appropriate nondestructive evaluation (NDE) inspection techniques that can detect corrosion (or conditions that would enhance the corrosion process) without the necessary downtime and expense of removing the insulation, and then replacing and repairing it. Recognizing how severe and costly the problem is, the Materials Technology Institute of the Chemical Processing Industries (MTI) authorized a state-of-the-art survey (unpublished), Detection of Corrosion Through Insulation. This article summarizes MTI`s report and discusses the application of NDE methods for the detection of corrosion through insulation (CTI). This entails inspection for defects (corrosion, erosion, pitting, cracking, thinning, and others) in components covered with insulation, without disturbing the insulation. The defects may be located on the inside diameter, the outside diameter, or within the wall of the component. A portion (subset) of this corrosion problem is often called corrosion under insulation (CUI). This refers only to damage occurring between the inside layer of the insulation and the outside surface of the metal component.

  19. Corrosion consequences of microfouling in water reclamation systems

    NASA Technical Reports Server (NTRS)

    Ford, Tim; Mitchell, Ralph

    1991-01-01

    This paper examines the potential fouling and corrosion problems associated with microbial film formation throughout the water reclamation system (WRS) designed for the Space Station Freedom. It is shown that the use of advanced metal sputtering techiques combined with image analysis and FTIR spectroscopy will present realistic solutions for investigating the formation and function of biofilm on different alloys, the subsequent corrosion, and the efficiency of different treatments. These techniques, used in combination with electrochemical measurements of corrosion, will provide a powerful approach to examinations of materials considered for use in the WRS.

  20. Designing geothermal power plants to avoid reinventing the corrosion wheel

    SciTech Connect

    Conover, Marshall F.

    1982-10-08

    This paper addresses how designers can take into account, the necessary chemical and materials precautions that other geothermal power plants have learned. Current worldwide geothermal power plant capacity is presented as well as a comparison of steam composition from seven different geothermal resources throughout the world. The similarities of corrosion impacts to areas of the power plants are discussed and include the turbines, gas extraction system, heat rejection system, electrical/electronic systems, and structures. Materials problems and solutions in these corrosion impact areas are identified and discussed. A geothermal power plant design team organization is identified and the efficacy of a new corrosion/materials engineering position is proposed.

  1. LINEAR ACCELERATOR

    DOEpatents

    Colgate, S.A.

    1958-05-27

    An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.

  2. TRU drum corrosion task team report

    SciTech Connect

    Kooda, K.E.; Lavery, C.A.; Zeek, D.P.

    1996-05-01

    During routine inspections in March 1996, transuranic (TRU) waste drums stored at the Radioactive Waste Management Complex (RWMC) were found with pinholes and leaking fluid. These drums were overpacked, and further inspection discovered over 200 drums with similar corrosion. A task team was assigned to investigate the problem with four specific objectives: to identify any other drums in RWMC TRU storage with pinhole corrosion; to evaluate the adequacy of the RWMC inspection process; to determine the precise mechanism(s) generating the pinhole drum corrosion; and to assess the implications of this event for WIPP certifiability of waste drums. The task team investigations analyzed the source of the pinholes to be Hcl-induced localized pitting corrosion. Hcl formation is directly related to the polychlorinated hydrocarbon volatile organic compounds (VOCs) in the waste. Most of the drums showing pinhole corrosion are from Content Code-003 (CC-003) because they contain the highest amounts of polychlorinated VOCs as determined by headspace gas analysis. CC-001 drums represent the only other content code with a significant number of pinhole corrosion drums because their headspace gas VOC content, although significantly less than CC-003, is far greater than that of the other content codes. The exact mechanisms of Hcl formation could not be determined, but radiolytic and reductive dechlorination and direct reduction of halocarbons were analyzed as the likely operable reactions. The team considered the entire range of feasible options, ranked and prioritized the alternatives, and recommended the optimal solution that maximizes protection of worker and public safety while minimizing impacts on RWMC and TRU program operations.

  3. Corrosion testing using isotopes

    DOEpatents

    Hohorst, F.A.

    1995-12-05

    A method is described for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested is described composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested is described composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness. 3 figs.

  4. Corrosion testing using isotopes

    DOEpatents

    Hohorst, Frederick A.

    1995-12-05

    A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness.

  5. Chemical Corrosion of Liquid-Phase Sintered SiC in Acidic/Alkaline Solutions Part 1. Corrosion in HNO3 Solution

    NASA Astrophysics Data System (ADS)

    Zhang, Lei; Zhang, Ming; He, Xinnong; Tang, Wenming

    2016-03-01

    The corrosion behavior of the liquid-phase sintered SiC (LPS-SiC) was studied by dipping in 3.53 mol/L HNO3 aqueous solution at room temperature and 70 °C, respectively. The weight loss, strength reduction and morphology evolution of the SiC specimens during corroding were revealed and also the chemical corrosion process and mechanism of the SiC specimens in the acidic solution were clarified. The results show that the corrosion of the LPS-SiC specimens in the HNO3 solution is selective. The SiC particles are almost free from corrosion, but the secondary phases of BaAl2Si2O8 (BAS) and Y2Si2O7 are corroded via an acid-alkali neutralization reaction. BAS has a higher corrosion rate than Y2Si2O7, resulting in the formation of the bamboo-leaf-like corrosion pits. As the SiC specimens etched in the HNO3 solution at room temperature for 75 days, about 80 μm thickness corrosion layer forms. The weight loss and bending strength reduction of the etched SiC specimens are 2.6 mg/cm2 and 52%, respectively. The corrosion of the SiC specimens is accelerated in the 70 °C HNO3 solution with a rate about five times bigger than that in the same corrosion medium at room temperature.

  6. Ultrasonic monitoring of pitting corrosion

    NASA Astrophysics Data System (ADS)

    Jarvis, A. J. C.; Cegla, F. B.; Bazaz, H.; Lozev, M.

    2013-01-01

    Exposure to corrosive substances in high temperature environments can cause damage accumulation in structural steels, particularly in the chemical and petrochemical industries. The interaction mechanisms are complex and varied; however initial damage propagation often manifests itself in the form of localized areas of increased material loss. Recent development of an ultrasonic wall thickness monitoring sensor capable of withstanding temperatures in excess of 500°C has allowed permanent monitoring within such hostile environments, providing information on how the shape of a pulse which has reflected from a corroding surface can change over time. Reconstructing localized corrosion depth and position may be possible by tracking such changes in reflected pulse shape, providing extra information on the state of the backwall and whether process conditions should be altered to increase plant life. This paper aims to experimentally investigate the effect certain localized features have on reflected pulse shape by `growing' artificial defects into the backwall while wall thickness is monitored using the sensor. The size and complexity of the three dimensional scattering problem lead to the development of a semi-analytical simulation based on the distributed point source method (DPSM) which is capable of simulating pulse reflection from complex surfaces measuring approximately 17×10λ Comparison to experimental results show that amplitude changes are predicted to within approximately 1dB and that pulse shape changes are accurately modelled. All experiments were carried out at room temperature, measurements at high temperature will be studied in the future.

  7. Anti-Corrosive Powder Particles

    NASA Technical Reports Server (NTRS)

    Parker, Donald; MacDowell, Louis, III

    2005-01-01

    The National Aeronautics and Space Administration (NASA) seeks partners for a new approach in protecting embedded steel surfaces from corrosion. Corrosion of reinforced steel in concrete structures is a significant problem for NASA structures at Kennedy Space Center (KSC) because of the close proximity of the structures to salt spray from the nearby Atlantic Ocean. In an effort to minimize the damage to such structures, coatings were developed that could be applied as liquids to the external surfaces of a substrate in which the metal structures were embedded. The Metallic Pigment Powder Particle technology was developed by NASA at KSC. This technology combines the metallic materials into a uniform particle. The resultant powder can be sprayed simultaneously with a liquid binder onto the surface of concrete structures with a uniform distribution of the metallic pigment for optimum cathodic protection of the underlying steel in the concrete. Metallic Pigment Powder Particle technology improves upon the performance of an earlier NASA technology Liquid Galvanic Coating (U.S. Patent No. 6,627,065).

  8. Corrosion by oxygen in oil and gas well casings

    SciTech Connect

    Martucci, S.; Dinon, M. )

    1993-10-01

    In September 1987, the Della 1 gas well in the Cooper Basin in South Australia blew out to surface. Originally, it was believed that sulfate-reducing bacteria (SRB) had perforated the casings, but numerous workovers on other wells and subsequent investigations indicated that SRB were not the major problem but that corrosion was simply occurring by an oxygen-reduction cathode process. The paper describes the failures and investigates the mechanism of corrosion.

  9. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  10. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  11. ION ACCELERATOR

    DOEpatents

    Bell, J.S.

    1959-09-15

    An arrangement for the drift tubes in a linear accelerator is described whereby each drift tube acts to shield the particles from the influence of the accelerating field and focuses the particles passing through the tube. In one embodiment the drift tube is splii longitudinally into quadrants supported along the axis of the accelerator by webs from a yoke, the quadrants. webs, and yoke being of magnetic material. A magnetic focusing action is produced by energizing a winding on each web to set up a magnetic field between adjacent quadrants. In the other embodiment the quadrants are electrically insulated from each other and have opposite polarity voltages on adjacent quadrants to provide an electric focusing fleld for the particles, with the quadrants spaced sufficienily close enough to shield the particles within the tube from the accelerating electric field.

  12. CORROSION TESTING IN SIMULATED TANK SOLUTIONS

    SciTech Connect

    Hoffman, E.

    2010-12-09

    Three simulated waste solutions representing wastes from tanks SY-102 (high nitrate, modified to exceed guidance limits), AN-107, and AY-102 were supplied by PNNL. Out of the three solutions tested, both optical and electrochemical results show that carbon steel samples corroded much faster in SY-102 (high nitrate) than in the other two solutions with lower ratios of nitrate to nitrite. The effect of the surface preparation was not as strong as the effect of solution chemistry. In areas with pristine mill-scale surface, no corrosion occurred even in the SY-102 (high nitrate) solution, however, corrosion occurred in the areas where the mill-scale was damaged or flaked off due to machining. Localized corrosion in the form of pitting in the vapor space of tank walls is an ongoing challenge to overcome in maintaining the structural integrity of the liquid waste tanks at the Savannah River and Hanford Sites. It has been shown that the liquid waste condensate chemistry influences the amount of corrosion that occurs along the walls of the storage tanks. To minimize pitting corrosion, an effort is underway to gain an understanding of the pitting response in various simulated waste solutions. Electrochemical testing has been used as an accelerated tool in the investigation of pitting corrosion. While significant effort has been undertaken to evaluate the pitting susceptibility of carbon steel in various simulated waste solutions, additional effort is needed to evaluate the effect of liquid waste supernates from six Hanford Site tanks (AY-101, AY-102, AN-102, AN-107, SY-102 (high Cl{sup -}), and SY-102 (high nitrate)) on carbon steel. Solutions were formulated at PNNL to replicate tank conditions, and in the case of SY-102, exceed Cl{sup -} and NO{sub 3}{sup -} conditions, respectively, to provide a contrast between in and out of specification limits. The majority of previous testing has been performed on pristine polished samples. To evaluate the actual tank carbon steel

  13. Biomedical accelerator mass spectrometry

    NASA Astrophysics Data System (ADS)

    Freeman, Stewart P. H. T.; Vogel, John S.

    1995-05-01

    Ultrasensitive SIMS with accelerator based spectrometers has recently begun to be applied to biomedical problems. Certain very long-lived radioisotopes of very low natural abundances can be used to trace metabolism at environmental dose levels ( [greater-or-equal, slanted] z mol in mg samples). 14C in particular can be employed to label a myriad of compounds. Competing technologies typically require super environmental doses that can perturb the system under investigation, followed by uncertain extrapolation to the low dose regime. 41Ca and 26Al are also used as elemental tracers. Given the sensitivity of the accelerator method, care must be taken to avoid contamination of the mass spectrometer and the apparatus employed in prior sample handling including chemical separation. This infant field comprises the efforts of a dozen accelerator laboratories. The Center for Accelerator Mass Spectrometry has been particularly active. In addition to collaborating with groups further afield, we are researching the kinematics and binding of genotoxins in-house, and we support innovative uses of our capability in the disciplines of chemistry, pharmacology, nutrition and physiology within the University of California. The field can be expected to grow further given the numerous potential applications and the efforts of several groups and companies to integrate more the accelerator technology into biomedical research programs; the development of miniaturized accelerator systems and ion sources capable of interfacing to conventional HPLC and GMC, etc. apparatus for complementary chemical analysis is anticipated for biomedical laboratories.

  14. LINEAR ACCELERATOR

    DOEpatents

    Christofilos, N.C.; Polk, I.J.

    1959-02-17

    Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.

  15. Corrosion Monitoring System

    SciTech Connect

    Dr. Russ Braunling

    2004-10-31

    The Corrosion Monitoring System (CMS) program developed and demonstrated a continuously on-line system that provides real-time corrosion information. The program focused on detecting pitting corrosion in its early stages. A new invention called the Intelligent Ultrasonic Probe (IUP) was patented on the program. The IUP uses ultrasonic guided waves to detect small defects and a Synthetic Aperture Focusing Technique (SAFT) algorithm to provide an image of the pits. Testing of the CMS demonstrated the capability to detect pits with dimensionality in the sub-millimeter range. The CMS was tested in both the laboratory and in a pulp and paper industrial plant. The system is capable of monitoring the plant from a remote location using the internet.

  16. A model of corrosion expertise

    SciTech Connect

    Trethewey, K.R.; Roberge, P.R.

    1996-10-01

    This paper describes an approach to reduce the complexity of knowledge engineering projects in corrosion by developing an object-oriented framework to guide the elicitation and organization of corrosion and materials engineering expertise. A model is presented into which corrosion expertise can be structured in a qualitative and quantitative way. This model could be used as the framework for a corrosion management expert system.

  17. Corrosion-resistant metal surfaces

    DOEpatents

    Sugama, Toshifumi

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  18. 49 CFR 192.455 - External corrosion control: Buried or submerged pipelines installed after July 31, 1971.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... meters), and soil resistivity measurements at potential profile peak locations, to adequately evaluate... minimum, soil resistivity measurements and tests for corrosion accelerating bacteria, that a corrosive... sentence, the operator shall conduct tests, including pipe-to-soil potential measurements with respect...

  19. Effect of mechanical cleaning on seawater corrosion of candidate OTEC heat exchanger materials. Part 1. Tests with M. A. N. brushes

    SciTech Connect

    Tipton, D G

    1980-09-01

    Corrosion evaluations were conducted on 3003 Alclad, 5052 aluminum, C7 0600 copper-nickel, AL-6X stainless steel, and commercially-pure titanium in natural seawater under simulated OTEC heat exchanger conditions to investigate the erosion-corrosion effects of mechanical tube cleaning. Test conditions of M.A.N. brush cleaning and M.A.N. brush cleaning + chlorination were compared with no mechanical cleaning over a seven month period. M.A.N. brushing significantly accelerated corrosion of 5052 aluminum and C7 0600 copper-nickel. Chlorination significantly accelerated erosion-corrosion of 3003 Alclad and 5052 aluminium. Chlorination somewhat decreased erosion-corrosion of C7 0600 copper-nickel. There was no detectable effect of M.A.N. brushing or chlorination on AL-6X stainless steel or titanium, although AL-6X exhibited crevice corrosion at tubing connections. 3003 Alclad and 5052 aluminum exhibited piting corrosion in all 3 test environments.

  20. Post-corrosive injuries of upper gastrointestinal tract.

    PubMed

    Chibishev, A; Simonovska, N; Shikole, A

    2010-01-01

    Acute poisonings with corrosive substances may cause serious chemical injuries to upper gastrointestinal tract, the most common location being the esophagus and the stomach. If the patient survives the acute phase of the poisoning, regenerative response may result in esophageal and/or gastric stenosis and increased risk for esophageal cancer. Acute corrosive intoxications pose a major problem in clinical toxicology since the most commonly affected population are the young with psychic disorders, suicidal intent and alcohol addiction. In establishing the diagnosis of acute corrosive poisonings, the severity of the post-corrosive endoscopic changes of the esophagus, stomach and duodenum is of major importance. According to Holinder and Fridman classification, post-corrosive endoscopic changes are classified in three degrees: First degree--superficial damage associated with hyperthermia, epithelial desquamation and mucous edema. Second degree--transmucous damage affecting all of the mucosal layers, followed by exudation, erosions and ulcerations. Third degree--transmural damage associated with ulcer's penetration in the deep layers of the tissue and neighboring organs. Severity of the lesions depends on the nature, quantity and concentration of the corrosive substance, the duration of exposure and current state of the exposed organs. Most often caustic injuries occur to the esophagus and stomach since the corrosive substance remains there for a longer period of time. Treatment of the acute corrosive intoxications include: neutralization of corrosive agents, antibiotics, corticosteroids, anti-secretory therapy, nutritional support, collagen synthesis inhibitors, esophageal dilation and stent placement, and surgery. The most common complications that may appear are: perforation, gastrointestinal bleeding, sepsis, esophageal strictures and stenosis, stenosis of gastric antrum and pylorus, cancer of the esophagus and the stomach. Today, owing to the substantially enhanced

  1. Corrosion monitoring using high-frequency guided ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Fromme, Paul

    2014-02-01

    Corrosion develops due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the structural integrity. The nondestructive detection and monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, guided wave modes were generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted and the wall thickness reduced by consecutive milling of the steel structure. Further measurements were conducted using accelerated corrosion in a salt water bath and the damage severity monitored. From the measured signal change due to the wave mode interference the wall thickness reduction was monitored. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

  2. Corrosion Embrittlement of Duralumin III Effect of the Previous Treatment of Sheet Material on the Susceptibility to This Type of Corrosion

    NASA Technical Reports Server (NTRS)

    Rawdon, Henry S

    1928-01-01

    As a result of testing, it was determined that control of the rate of quenching and the avoidance of accelerated aging by heating are the only means of modifying duralumin itself so as to minimize the intercrystalline form of corrosive attack. It is so simple a means that it should be adopted even though it may not completely prevent, but only reduce, this form of corrosive attack. By so doing, the need for protection of the surface is less urgent.

  3. Corrosion testing of urea-formaldehyde foam insulating material

    SciTech Connect

    Weil, R.; Graviano, A.; Sheppard, K.

    1980-09-01

    Two tests of the corrosiveness of urea-formaldehyde (UF) foam insulating materials were compared. One test, the Timm test, had test coupons foamed in place. In the second, the Canadian test, blocks of foam already set were placed in contact with test coupons. The Timm test uses 10 gage thick coupons, while the Canadian test specifies 3 mil thick ones. Two samples of UF foam were tested by the Timm and the Canadian tests. The electrical-resistance probes showed that the corrosion rate against steel was initially quite high, of the order of 12 to 20 mpy (mils per year). After about 20 days, the rate was almost zero. In the Timm test, the corrosion rates of steel coupons were of the order to 0.5 to 2 mpy when averaged over the 28 or 56 day test period. The greater corrosion rate of the thick coupons in the Canadian test as well as poor reproducibility of the corrosion rates was attributed primarily to variations in the contact areas between the sample and the UF foam. The corrosion rates of galvanized steel coupons in the Canadian test in several cases exceeded the failure value. In the Timm test, the corrosion rates averaged over the whole test period were quite low. The corrosion rates of copper and aluminum in both tests were quite low. On the basis of the results of this study the following recommendations for a corrosion-test procedure for UF foam were made: two corrosion tests should be conducted, one for foam while curing and one after it has stabilized; the Timm test for corrosiveness while curing should be used, but for only 1 to 2 days; the test for corrosiveness after stabilizing should be of the accelerated type such as the Canadian one. To insure a constant-contact area, thicker coupons should be used; and the coupons for both tests should have a controlled part of the area not in contact with the foam to simulate field conditions.

  4. Intermediate attack in crevice corrosion by cathodic focusing

    NASA Astrophysics Data System (ADS)

    Stewart, Kevin Charles

    Intermediate attack (IA) is an interesting phenomenon in crevice corrosion. The typical morphology of crevice attack shows an unattacked region near the crevice mouth, a region of extensive damage at slightly greater depths and an additional unattacked region at still greater depths. This pattern suggests that crevice corrosion is governed by the interaction between two forces. One force accelerates corrosion with increasing depth into a crevice. The other force acts to retard dissolution as distance from the crevice mouth increases. This second, ameliorative force, is not accounted for in conventional theories of crevice corrosion. Traditionally, the exciting force in crevice corrosion is thought to be either acidification due to metal cation hydrolysis, the Critical Crevice Solution Model, (CCS), or depolarization of a passivated material, the Critical Potential Drop Model (IR*). One potential mitigating force for corrosion is reduction in driving force due to resistive potential drop. This explanation lacking in that IR losses can only depolarize a material to its open circuit value. Corrosion rates can be significant even at open circuit in the highly aggressive, acidic chloride environments which are thought to exist in crevices. A superior theory to explain IA is the Cathodic Focusing (CF) model which is developed in this dissertation. It accounts for the chemical effects of cathodic reactions inside a crevice. These reactions are especially important in those regions of the crevice that are at or near the open circuit potential. Many of the likely cathodic reactions generate hydroxyl ions which will raise the local pH. This pH rise can be very protective of the crevice material. In order to test and explore the suitability of the CCS and IR* models to predict IA a new code for modeling crevice corrosion was needed. This dissertation presents the background and verification of CREVICER, a new code for modeling crevice corrosion. The code is a 2-D(+), temporal

  5. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  6. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K. NY); Cunningham, Kevin M.

    2011-06-07

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  7. DWPF corrosion study

    SciTech Connect

    Selby, C.L.

    1986-12-17

    Corrosion of candidate alloys for the DWPF SRAT, SME, and melter was tested in the large (1/3 scale) SRAT/SME, the 200th scale SRAT/SME, and the LSFM. Flat or twisted coupons with or without a weld bead and U-bend specimens (specimens bent into a ''U'' shape and bolted together at the ends to stress the bend area) were installed on racks that ensured electrical isolation to avoid galvanic effects. Teflon/reg sign/ washers isolated the low temperature exposure racks and ceramic washers isolated the high temperature exposure racks. Serrated washers simulated crevices, but crevice corrosion did not result. 9 refs., 9 tabs.

  8. Corrosion performance of laser-welded austenitic-ferritic connections

    NASA Astrophysics Data System (ADS)

    Weigl, M.; Schmidt, M.

    2013-02-01

    In order to reduce the material costs of white-goods made of stainless steels, tailored constructions with unequally alloyed stainless steels shall be used. For that purpose nickel-alloyed austenitic stainless steels are supposed to be limited to zones with demanding needs for corrosions resistance, whereas nickel-free ferritic stainless steels provide an attractive cost-performance ratio for the remaining components of a system. Particularly the present article discusses the corrosion performance of austenitic-ferritic connections, welded with high-power disc lasers at accelerated feed rates, as a function of the shielding gas composition and the surface condition.

  9. Corrosion and repairs of ammonium carbamate decomposers

    SciTech Connect

    De Romero, M.F.; Galban, J.P.

    1996-05-01

    Corrosion-erosion problems occurred in the carbon steel base metal of the ammonium carbamate decomposers in an urea extraction process lined with type 316L (UNS S31603) urea grade stainless steel. The cladding was replaced by weld overlay using a semiautomatic gas metal arc welding process. The first layer was alloy 25%Cr-15%Ni-2%Mo (UNS W30923); the second layer was alloy 25%Cr-22%Ni-2%Mo (UNS W31020).

  10. The performance analysis of distributed Brillouin corrosion sensors for steel reinforced concrete structures.

    PubMed

    Wei, Heming; Zhao, Xuefeng; Kong, Xianglong; Zhang, Pinglei; Cui, Yanjun; Sun, Changsen

    2013-01-01

    The Brillouin optical time-domain analysis (BOTDA)-based optical fiber method has been proposed to measure strain variations caused by corrosion expansion. Spatial resolutions of 1 m can be achieved with this kind of Brillouin sensor for detecting the distributed strain. However, when the sensing fiber is wound around the steel rebar in a number of circles in a range of several meters, this spatial resolution still has limitations for corrosion monitoring. Here, we employed a low-coherent fiber-optic strain sensor (LCFS) to survey the performance of Brillouin sensors based on the fact that the deformation measured by the LCFS equals the integral of the strains obtained from Brillouin sensors. An electrochemical accelerated corrosion experiment was carried out and the corrosion expansion was monitored by both BOTDA and the LCFS. Results demonstrated that the BOTDA can only measure the expansion strain of about 1,000 με, which was generated by the 18 mm steel rebar corrosion, but, the LCFS had high sensitivity from the beginning of corrosion to the destruction of the structure, and no obvious difference in expansion speed was observed during the acceleration stage of the corrosion developed in the reinforced concrete (RC) specimens. These results proved that the BOTDA method could only be employed to monitor the corrosion inside the structure in the early stage. PMID:24379048

  11. The Performance Analysis of Distributed Brillouin Corrosion Sensors for Steel Reinforced Concrete Structures

    PubMed Central

    Wei, Heming; Zhao, Xuefeng; Kong, Xianglong; Zhang, Pinglei; Cui, Yanjun; Sun, Changsen

    2014-01-01

    The Brillouin optical time-domain analysis (BOTDA)-based optical fiber method has been proposed to measure strain variations caused by corrosion expansion. Spatial resolutions of 1 m can be achieved with this kind of Brillouin sensor for detecting the distributed strain. However, when the sensing fiber is wound around the steel rebar in a number of circles in a range of several meters, this spatial resolution still has limitations for corrosion monitoring. Here, we employed a low-coherent fiber-optic strain sensor (LCFS) to survey the performance of Brillouin sensors based on the fact that the deformation measured by the LCFS equals the integral of the strains obtained from Brillouin sensors. An electrochemical accelerated corrosion experiment was carried out and the corrosion expansion was monitored by both BOTDA and the LCFS. Results demonstrated that the BOTDA can only measure the expansion strain of about 1,000 με, which was generated by the 18 mm steel rebar corrosion, but, the LCFS had high sensitivity from the beginning of corrosion to the destruction of the structure, and no obvious difference in expansion speed was observed during the acceleration stage of the corrosion developed in the reinforced concrete (RC) specimens. These results proved that the BOTDA method could only be employed to monitor the corrosion inside the structure in the early stage. PMID:24379048

  12. Fracture mechanics and corrosion fatigue.

    NASA Technical Reports Server (NTRS)

    Mcevily, A. J.; Wei, R. P.

    1972-01-01

    Review of the current state-of-the-art in fracture mechanics, particularly in relation to the study of problems in environment-enhanced fatigue crack growth. The usefulness of this approach in developing understanding of the mechanisms for environmental embrittlement and its engineering utility are discussed. After a brief review of the evolution of the fracture mechanics approach and the study of environmental effects on the fatigue behavior of materials, a study is made of the response of materials to fatigue and corrosion fatigue, the modeling of the mechanisms of the fatigue process is considered, and the application of knowledge of fatigue crack growth to the prediction of the high cycle life of unnotched specimens is illustrated.

  13. Current techniques in acid-chloride corrosion control and monitoring at The Geysers

    SciTech Connect

    Hirtz, Paul; Buck, Cliff; Kunzman, Russell

    1991-01-01

    Acid chloride corrosion of geothermal well casings, production piping and power plant equipment has resulted in costly corrosion damage, frequent curtailments of power plants and the permanent shut-in of wells in certain areas of The Geysers. Techniques have been developed to mitigate these corrosion problems, allowing continued production of steam from high chloride wells with minimal impact on production and power generation facilities.The optimization of water and caustic steam scrubbing, steam/liquid separation and process fluid chemistry has led to effective and reliable corrosion mitigation systems currently in routine use at The Geysers. When properly operated, these systems can yield steam purities equal to or greater than those encountered in areas of The Geysers where chloride corrosion is not a problem. Developments in corrosion monitoring techniques, steam sampling and analytical methodologies for trace impurities, and computer modeling of the fluid chemistry has been instrumental in the success of this technology.

  14. Electrochemical noise measurements of sustained microbially influenced pitting corrosion in a laboratory flow loop system.

    SciTech Connect

    Lin, Y. J.

    1999-01-13

    Because of the chaotic nature of the corrosion process and the complexity of the electrochemical noise signals that are generated, there is no generally accepted method of measuring and interpreting these signals that allows the consistent detection and identification of sustained localized pitting (SLP) as compared to general corrosion. We have reexamined electrochemical noise analysis (ENA) of localized corrosion using different hardware, signal collection, and signal processing designs than those used in conventional ENA techniques. The new data acquisition system was designed to identify and monitor the progress of SLP by analyzing the power spectral density (PSD) of the trend of the corrosion current noise level (CNL) and potential noise level (PNL). Each CNL and PNL data point was calculated from the root-mean- square value of the ac components of current and potential fluctuation signals, which were measured simultaneously during a short time period. The PSD analysis results consistently demonstrated that the trends of PNL and CNL contain information that can be used to differentiate between SLP and general corrosion mechanisms. The degree of linear slope in the low-frequency portion of the PSD analysis was correlated with the SLP process. Laboratory metal coupons as well as commercial corrosion probes were tested to ensure the reproducibility and consistency of the results. The on-line monitoring capability of this new ENA method was evaluated in a bench-scale flow-loop system, which simulated microbially influenced corrosion (MIC) activity. The conditions in the test flow-loop system were controlled by the addition of microbes and different substrates to favor accelerated corrosion. The ENA results demonstrated that this in-situ corrosion monitoring system could effectively identify SLP corrosion associated with MIC, compared to a more uniform general corrosion mechanism. A reduction in SLP activity could be clearly detected by the ENA monitoring system

  15. Automated corrosion system in a moist environment

    SciTech Connect

    Hallman, R.L. Jr.; Calhoun, C.L.

    1999-03-19

    In an effort to assist researchers investigating the moisture-generated corrosion of metals and ceramics, a unique exposure system was developed. The initial goal of this system was to monitor corrosion ranging from a few monolayers at the outset of the corrosion process to high mass gains in more extensively corroded material. The new system uses a small robot arm for sample manipulation; gravimetric and Fourier transform infrared (FTIR) spectroscopy for corrosion-product determination; and a gas blending system to control the moisture content of the glove box in which the system is housed. The system's computer control can be configured to coordinate the examination of as many as 20 samples by periodic weighing and FTIR scanning. The computer also performs such functions as data logging of the temperature and pressure of the system and of the flow rate and moisture content of the purge gas. One main benefit of the computer-controlled robotic system is its ability to monitor samples 2 4 hours a day with precision control; this reduces problems stemming from human error or inconsistency of human technique.

  16. The effect of surface roughness on the fretting corrosion of 316L stainless steel biomaterial surfaces

    NASA Astrophysics Data System (ADS)

    Shenoy, Aarti

    The medical device industry is still seeking answers to the mechanically-assisted corrosion (MAC) problem, which becomes increasingly important due to modularity in design. MAC manifests in various forms, some of which are fretting corrosion, crevice corrosion and stress corrosion. Several studies have been conducted to understand the causes and the factors that affect fretting corrosion. Some of the factors are the applied load, surface potential, oxide film characteristics and solution chemistry near the interface. Surface properties such as surface roughness determine the topography of the surface and the nature of asperity-asperity contact, which is a factor that would determine the mechanically assisted corrosion behavior of the interface, like the stem-neck and head-neck taper junctions in modular hip replacement devices. This study aims to understand the correlation between surface roughness of 316L stainless steel samples and fretting corrosion behavior using a variable load pin-on-disc test. It was found that the smoother surfaces are associated with lower fretting currents. However, smoother surfaces also created the conditions for fretting initiated crevice corrosion to occur more readily. Fretting corrosion regimes and the severity are thus dependent upon the surface roughness. A possible explanation could be due to the inverse relationship between the interasperity distance parameter, Delta, and fretting currents. The coefficient of friction between the two surfaces in contact however remained unaffected by surface roughness, but decreased with increasing load. Smoother surfaces, while lowering fretting corrosion reactions can enhance crevice corrosion reactions in 316L stainless steel interfaces.

  17. Corrosion behavior of Ti-39Nb alloy for dentistry.

    PubMed

    Fojt, Jaroslav; Joska, Ludek; Malek, Jaroslav; Sefl, Vaclav

    2015-11-01

    To increase an orthopedic implant's lifetime, researchers are now concerned on the development of new titanium alloys with suitable mechanical properties (low elastic modulus-high fatigue strength), corrosion resistance and good workability. Corrosion resistance of the newly developed titanium alloys should be comparable with that of pure titanium. The effect of medical preparations containing fluoride ions represents a specific problem related to the use of titanium based materials in dentistry. The aim of this study was to determine the corrosion behavior of β titanium alloy Ti-39Nb in physiological saline solution and in physiological solution containing fluoride ions. Corrosion behavior was studied using standard electrochemical techniques and X-ray photoelectron spectroscopy. It was found that corrosion properties of the studied alloy were comparable with the properties of titanium grade 2. The passive layer was based on the oxides of titanium and niobium in several oxidation states. Alloying with niobium, which was the important part of the alloy passive layer, resulted in no significant changes of corrosion behavior. In the presence of fluoride ions, the corrosion resistance was higher than the resistance of titanium. PMID:26249624

  18. Corrosion potential analysis system

    NASA Astrophysics Data System (ADS)

    Kiefer, Karl F.

    1998-03-01

    Many cities in the northeastern U.S. transport electrical power from place to place via underground cables, which utilize voltages from 68 kv to 348 kv. These cables are placed in seamless steel pipe to protect the conductors. These buried pipe-type-cables (PTCs) are carefully designed and constantly pressurized with transformer oil to prevent any possible contamination. A protective coating placed on the outside diameter of the pipe during manufacture protects the steel pipe from the soil environment. Notwithstanding the protection mechanisms available, the pipes remain vulnerable to electrochemical corrosion processes. If undetected, corrosion can cause the pipes to leak transformer oil into the environment. These leaks can assume serious proportions due to the constant pressure on the inside of the pipe. A need exists for a detection system that can dynamically monitor the corrosive potential on the length of the pipe and dynamically adjust cathodic protection to counter local and global changes in the cathodic environment surrounding the pipes. The northeastern United States contains approximately 1000 miles of this pipe. This milage is critical to the transportation and distribution of power. So critical, that each of the pipe runs has a redundant double running parallel to it. Invocon, Inc. proposed and tested a technically unique and cost effective solution to detect critical corrosion potential and to communicate that information to a central data collection and analysis location. Invocon's solution utilizes the steel of the casing pipe as a communication medium. Each data gathering station on the pipe can act as a relay for information gathered elsewhere on the pipe. These stations must have 'smart' network configuration algorithms that constantly test various communication paths and determine the best and most power efficient route through which information should flow. Each network station also performs data acquisition and analysis tasks that ultimately

  19. Acceleration Studies

    NASA Technical Reports Server (NTRS)

    Rogers, Melissa J. B.

    1993-01-01

    Work to support the NASA MSFC Acceleration Characterization and Analysis Project (ACAP) was performed. Four tasks (analysis development, analysis research, analysis documentation, and acceleration analysis) were addressed by parallel projects. Work concentrated on preparation for and implementation of near real-time SAMS data analysis during the USMP-1 mission. User support documents and case specific software documentation and tutorials were developed. Information and results were presented to microgravity users. ACAP computer facilities need to be fully implemented and networked, data resources must be cataloged and accessible, future microgravity missions must be coordinated, and continued Orbiter characterization is necessary.

  20. Corrosion of rock anchors in US coal mines

    NASA Astrophysics Data System (ADS)

    Bylapudi, Gopi

    anchors installed in the mines with respect to corrosion potential and corrosion current measured. The results of this research were statistically validated. This research will have direct consequence to the rock related safety. The results of this research indicate that certain corrosive conditions are commonly found in mines but uniform corrosion (around 0.01-0.03mm loss per year across the diameter) is generally not considered a serious issue. From this study, longer term research for longterm excavation support is recommended that could quantify the problem depending on the rock anchor used and specific strata conditions.

  1. Mobile evaporator corrosion test results

    SciTech Connect

    Rozeveld, A.; Chamberlain, D.B.

    1997-05-01

    Laboratory corrosion tests were conducted on eight candidates to select a durable and cost-effective alloy for use in mobile evaporators to process radioactive waste solutions. Based on an extensive literature survey of corrosion data, three stainless steel alloys (304L, 316L, AL-6XN), four nickel-based alloys (825, 625, 690, G-30), and titanium were selected for testing. The corrosion tests included vapor phase, liquid junction (interface), liquid immersion, and crevice corrosion tests on plain and welded samples of candidate materials. Tests were conducted at 80{degrees}C for 45 days in two different test solutions: a nitric acid solution. to simulate evaporator conditions during the processing of the cesium ion-exchange eluant and a highly alkaline sodium hydroxide solution to simulate the composition of Tank 241-AW-101 during evaporation. All of the alloys exhibited excellent corrosion resistance in the alkaline test solution. Corrosion rates were very low and localized corrosion was not observed. Results from the nitric acid tests showed that only 316L stainless steel did not meet our performance criteria. The 316L welded interface and crevice specimens had rates of 22.2 mpy and 21.8 mpy, respectively, which exceeds the maximum corrosion rate of 20 mpy. The other welded samples had about the same corrosion resistance as the plain samples. None of the welded samples showed preferential weld or heat-affected zone (HAZ) attack. Vapor corrosion was negligible for all alloys. All of the alloys except 316L exhibited either {open_quotes}satisfactory{close_quotes} (2-20 mpy) or {open_quotes}excellent{close_quotes} (<2 mpy) corrosion resistance as defined by National Association of Corrosion Engineers. However, many of the alloys experienced intergranular corrosion in the nitric acid test solution, which could indicate a susceptibility to stress corrosion cracking (SCC) in this environment.

  2. Requirements of a proton beam accelerator for an accelerator-driven reactor

    SciTech Connect

    Takahashi, H.; Zhao, Y.; Tsoupas, N.; An, Y.; Yamazaki, Y.

    1997-12-31

    When the authors first proposed an accelerator-driven reactor, the concept was opposed by physicists who had earlier used the accelerator for their physics experiments. This opposition arose because they had nuisance experiences in that the accelerator was not reliable, and very often disrupted their work as the accelerator shut down due to electric tripping. This paper discusses the requirements for the proton beam accelerator. It addresses how to solve the tripping problem and how to shape the proton beam.

  3. High energy plasma accelerators

    SciTech Connect

    Tajima, T.

    1985-05-01

    Colinear intense laser beams ..omega../sub 0/, kappa/sub 0/ and ..omega../sub 1/, kappa/sub 1/ shone on a plasma with frequency separation equal to the electron plasma frequency ..omega../sub pe/ are capable of creating a coherent large longitudinal electric field E/sub L/ = mc ..omega../sub pe//e of the order of 1GeV/cm for a plasma density of 10/sup 18/ cm/sup -3/ through the laser beat excitation of plasma oscillations. Accompanying favorable and deleterious physical effects using this process for a high energy beat-wave accelerator are discussed: the longitudinal dephasing, pump depletion, the transverse laser diffraction, plasma turbulence effects, self-steepening, self-focusing, etc. The basic equation, the driven nonlinear Schroedinger equation, is derived to describe this system. Advanced accelerator concepts to overcome some of these problems are proposed, including the plasma fiber accelerator of various variations. An advanced laser architecture suitable for the beat-wave accelerator is suggested. Accelerator physics issues such as the luminosity are discussed. Applications of the present process to the current drive in a plasma and to the excitation of collective oscillations within nuclei are also discussed.

  4. Stress corrosion cracking of an aluminum alloy used in external fixation devices.

    PubMed

    Cartner, Jacob L; Haggard, Warren O; Ong, Joo L; Bumgardner, Joel D

    2008-08-01

    Treatment for compound and/or comminuted fractures is frequently accomplished via external fixation. To achieve stability, the compositions of external fixators generally include aluminum alloy components due to their high strength-to-weight ratios. These alloys are particularly susceptible to corrosion in chloride environments. There have been several clinical cases of fixator failure in which corrosion was cited as a potential mechanism. The aim of this study was to evaluate the effects of physiological environments on the corrosion susceptibility of aluminum 7075-T6, since it is used in orthopedic external fixation devices. Electrochemical corrosion curves and alternate immersion stress corrosion cracking tests indicated aluminum 7075-T6 is susceptible to corrosive attack when placed in physiological environments. Pit initiated stress corrosion cracking was the primary form of alloy corrosion, and subsequent fracture, in this study. Anodization of the alloy provided a protective layer, but also caused a decrease in passivity ranges. These data suggest that once the anodization layer is disrupted, accelerated corrosion processes occur. PMID:18257055

  5. Corrosion performance of alumina scales in coal gasification environments

    SciTech Connect

    Natesan, K.

    1997-02-01

    Corrosion of metallic structural materials in complex gas environments of coal gasification is a potential problem. The corrosion process is dictated by concentrations of two key constituents: sulfur as H{sub 2}S and Cl as HCl. This paper examines the corrosion performance of alumina scales that are thermally grown on Fe-base alloys during exposure to O/S mixed-gas environments. The results are compared with the performance of chromia-forming alloys in similar environments. The paper also discusses the available information on corrosion performance of alloys whose surfaces were enriched with Al by the pack-diffusion process, by the electrospark deposition process, or by weld overlay techniques.

  6. Stress corrosion cracking of zirconium used in the reprocessing plant

    SciTech Connect

    Kato, Chiaki; Motooka, Takafumi; Yamamoto, Masahiro

    2007-07-01

    We investigated stress corrosion cracking (SCC) of zirconium by constant load test and the small-scale mock-up test simulated the fuel dissolve. These tests operated in the simulated solution, which substituted non-radioactive elements, i.e. V with radioactive elements such as Pu and Np. From the results of constant load test, the cracks were not observed on 150 MPa after 908 hours in approximately 3 % strain. However a lot of cracks caused by SCC were observed over 20 % strain under high tensile stress in the simulated solution and the heat-transfer condition having more corrosive circumstance and noble potential accelerated the susceptibility of SCC. The cracking behavior would be caused by the creep phenomena. The small-scale mock-up test had been operated for about 50000 hours during 7 year. From the results, zirconium showed excellent corrosion resistance and no SCC was observed during these long-term operations. (authors)

  7. Plasma accelerator

    DOEpatents

    Wang, Zhehui; Barnes, Cris W.

    2002-01-01

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  8. Accelerated Achievement

    ERIC Educational Resources Information Center

    Ford, William J.

    2010-01-01

    This article focuses on the accelerated associate degree program at Ivy Tech Community College (Indiana) in which low-income students will receive an associate degree in one year. The three-year pilot program is funded by a $2.3 million grant from the Lumina Foundation for Education in Indianapolis and a $270,000 grant from the Indiana Commission…

  9. ACCELERATION INTEGRATOR

    DOEpatents

    Pope, K.E.

    1958-01-01

    This patent relates to an improved acceleration integrator and more particularly to apparatus of this nature which is gyrostabilized. The device may be used to sense the attainment by an airborne vehicle of a predetermined velocitv or distance along a given vector path. In its broad aspects, the acceleration integrator utilizes a magnetized element rotatable driven by a synchronous motor and having a cylin drical flux gap and a restrained eddy- current drag cap deposed to move into the gap. The angular velocity imparted to the rotatable cap shaft is transmitted in a positive manner to the magnetized element through a servo feedback loop. The resultant angular velocity of tae cap is proportional to the acceleration of the housing in this manner and means may be used to measure the velocity and operate switches at a pre-set magnitude. To make the above-described dcvice sensitive to acceleration in only one direction the magnetized element forms the spinning inertia element of a free gyroscope, and the outer housing functions as a gimbal of a gyroscope.

  10. Particle acceleration

    NASA Technical Reports Server (NTRS)

    Vlahos, L.; Machado, M. E.; Ramaty, R.; Murphy, R. J.; Alissandrakis, C.; Bai, T.; Batchelor, D.; Benz, A. O.; Chupp, E.; Ellison, D.

    1986-01-01

    Data is compiled from Solar Maximum Mission and Hinothori satellites, particle detectors in several satellites, ground based instruments, and balloon flights in order to answer fundamental questions relating to: (1) the requirements for the coronal magnetic field structure in the vicinity of the energization source; (2) the height (above the photosphere) of the energization source; (3) the time of energization; (4) transistion between coronal heating and flares; (5) evidence for purely thermal, purely nonthermal and hybrid type flares; (6) the time characteristics of the energization source; (7) whether every flare accelerates protons; (8) the location of the interaction site of the ions and relativistic electrons; (9) the energy spectra for ions and relativistic electrons; (10) the relationship between particles at the Sun and interplanetary space; (11) evidence for more than one acceleration mechanism; (12) whether there is single mechanism that will accelerate particles to all energies and also heat the plasma; and (13) how fast the existing mechanisms accelerate electrons up to several MeV and ions to 1 GeV.

  11. Experiences with combined corrosion effects on stainless steel due to chlorides and H{sub 2}S

    SciTech Connect

    Russell, M.T.; Wortham, G.M.; Lawson, D.M.

    1999-07-01

    Chloride contamination of amines in contact with stainless steel creates a well known potential for stress corrosion cracking (SCC). A far less recognized hazard of chloride contamination, when sulfides are present, is drastically accelerated generalized corrosion. Chloride induced corrosion can be avoided with an inlet gas reverse flow coalescer and an inlet slug catcher to knock out brine bearing produced water. If the amine is already contaminated with chlorides, steps can be taken to minimize this type of corrosion such as better amine filtration, amine reclamation and using stainless steel with higher nickel contents.

  12. The Examination of Afyonkarahisar's Geothermal System Corrosion

    NASA Astrophysics Data System (ADS)

    Buyuksagis, A.; Erol, S.

    2013-02-01

    Corrosion and scaling of metal surfaces are the major problems caused by geothermal fluids when metallic structures are used. This article describes a study of corrosion and scaling problems in the Afyonkarahisar Geothermal Heating System (AFJET) in Afyonkarahisar, Turkey. Water analysis, XRD, SEM, EDX, IC, ICP-OES analyses, and electrochemical methods were used in this study. Pentasodium triphosphate (Na5P3O10), maleic anhydride (C4H2O3), and 1,3-benzendisulfonic acid disodium salt (C6H4Na2O6S2) were used as corrosion inhibitors. Tests were carried out using geothermal water from AF11 well. The experimental temperatures were chosen as 298, 333, and 358 K. Inhibitor concentrations were chosen as 1 × 10-1, 1 × 10-2, 1 × 10-3, and 1 × 10-4 mol/dm3. Moreover, mixed inhibitor solutions were prepared using the inhibitor concentrations that showed the best inhibition. The first mixed inhibitor solution showed 96% inhibition. The second mixed inhibitor solution showed 90% inhibition. The tested inhibitors act as anodic inhibitors. XRD analysis shows that there is CaCO3 aragonite scaling in the system. Increasing TDS, alkalinity, and hardness all promote scale formation. The photomicrographs from SEM-EDX and the metallographic microscope show that the tested inhibitors form a protective film on the surface. IC and ICP-OES analyses show that the concentration of Ca2+ is very high, which supports scale formation.

  13. Corrosion in a temperature gradient

    SciTech Connect

    Covino, Bernard S., Jr.; Holcomb, Gordon R.; Cramer, Stephen D.; Bullard, Sophie J.; Ziomek-Moroz, Margaret; White, M.L.

    2003-01-01

    High temperature corrosion limits the operation of equipment used in the Power Generation Industry. Some of the more destructive corrosive attack occurs on the surfaces of heat exchangers, boilers, and turbines where the alloys are subjected to large temperature gradients that cause a high heat flux through the accumulated ash, the corrosion product, and the alloy. Most current and past corrosion research has, however, been conducted under isothermal conditions. Research on the thermal-gradient-affected corrosion of various metals and alloys is currently being studied at the Albany Research Center’s SECERF (Severe Environment Corrosion and Erosion Research Facility) laboratory. The purpose of this research is to verify theoretical models of heat flux effects on corrosion and to quantify the differences between isothermal and thermal gradient corrosion effects. The effect of a temperature gradient and the resulting heat flux on corrosion of alloys with protective oxide scales is being examined by studying point defect diffusion and corrosion rates. Fick’s first law of diffusion was expanded, using irreversible thermodynamics, to include a heat flux term – a Soret effect. Oxide growth rates are being measured for the high temperature corrosion of cobalt at a metal surface temperature of 900ºC. Corrosion rates are also being determined for the high temperature corrosion of carbon steel boiler tubes in a simulated waste combustion environment consisting of O2, CO2, N2, and water vapor. Tests are being conducted both isothermally and in the presence of a temperature gradient to verify the effects of a heat flux and to compare to isothermal oxidation.

  14. Corrosion of zirconium alloys in concentrated lithium hydroxide solutions

    NASA Astrophysics Data System (ADS)

    Müller, S.; Lanzani, L.

    2013-08-01

    The accelerated corrosion of two alloys used as fuel cladding material, such as Zircaloy-4 and Zr-1%Nb has been studied in concentrated lithium hydroxide (LiOH) solutions at high temperature and pressure. Zr-2.5%Nb pressure tube material (PT) was also tested in order to analyze the influence of the amount of β-Zr phase on the accelerated corrosion of the Zr-Nb alloys. The microstructure of Zircaloy-4 consisted of α-Zr equiaxed grains whereas that of Zr-2.5%Nb (PT) and Zr-1%Nb alloys showed a two phase (α-Zr + β-Zr) microstructure. Autoclaving tests were performed in LiOH solutions with concentrations ranging from 0.1 M to 1 M for 16 h at 343 °C, and also in steam at 400 °C. The extent of corrosion was evaluated through the weight gain and visual appearance of the oxide. Measurements included hydrogen uptake and oxide thickness. Optical microscopy observations of the hydride distribution were also made on the specimens. Results showed that Zircaloy-4 suffered accelerated corrosion at 0.7 M and 1 M LiOH concentrations with high hydrogen uptakes (˜50%). For these LiOH concentrations, although the Zr-2.5%Nb (PT) and Zr-1%Nb alloys showed weight gains higher than the threshold value established for the "transition", their hydrogen uptakes were low (˜1%). This behavior indicates that at the early stages of the corrosion process in these solutions, an oxide barrier layer may be present at the metal/oxide interface of these Zr-Nb alloys. The lower amount of β-Zr phase in Zr-1%Nb improves the characteristics of the oxide layer in relation to that formed on Zr-2.5%Nb and does not affect the hydrogen uptake.

  15. Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

    PubMed Central

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring. PMID:22346672

  16. Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

    PubMed

    Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

    2011-01-01

    In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring. PMID:22346672

  17. Corrosion protection of steel by thin coatings of starch-oil dry lubricants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. Dry lubricants reduce friction between two metal surfaces. This research investigated the inhibition of corrosive behavior a dry lubricant formulation consisting of jet-cooked corn starch and soyb...

  18. EFFECTS OF CORROSIVE TREATMENT ON STAINLESS STEEL SURFACE FINISHES AND BACTERIAL ATTACHMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion, an important factor for the durability of a metal finish after exposure to water and chemicals during processing, is a real concern for many wet process industries. The effects of rouging, corrosion, and biofouling are costly problems on the surface of stainless steel, the most common mat...

  19. Copper and Lead Corrosion in a Full Scale Home Plumbning system Simulation

    EPA Science Inventory

    The corrosion of household or premise plumbing materials (such as copper, brass, and solder) and the metal release that results from that corrosion can cause numerous problems, ranging from elevated lead and copper levels to blue water and copper pinhole leaks. If left untreate...

  20. Corrosion Protection of Steel by Thin Coatings of Starch-oil Emulsions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corrosion of materials is one of the most serious and challenging problems faced worldwide by industry. This research investigated the inhibition of corrosive behavior by jet-cooked starch-soybean oil composites on SAE 1010 steel. Electrochemical Impedance Spectroscopy (EIS) was used to evaluate t...

  1. A Comprehensive Investigation of Copper Pitting Corrosion in a Drinking Water Distribution System

    EPA Science Inventory

    Copper pipe pitting is a complicated corrosion process for which exact causes and solutions are uncertain. This paper presents the findings of a comprehensive investigation of a cold water copper pitting corrosion problem in a drinking water distribution system, including a refi...

  2. A SIMPLE APPROACH TO ASSESSING COPPER PITTING CORROSION TENDENCIES AND DEVELOPING CONTROL STRATEGIES

    EPA Science Inventory

    Localized corrosion of copper plumbing in drinking water distribution systems can lead to pinhole leaks, which are a growing problem for many homeowners. Although water quality is one factor that can be responsible for localized copper corrosion, there is not a good approach to ...

  3. A SIMPLE APPROACH TO ASSESSING COPPER PITTING CORROSION TENDENCIES AND DEVELOPING CONTROL STRATEGIES

    EPA Science Inventory

    Localized corrosion of copper premise plumbing in drinking water distribution systems can lead to pinhole leaks, which are a growing problem for many homeowners. Despite the fact that water quality is an important factor associated with localized copper corrosion, definitive appr...

  4. Corrosion guard tubing nipple

    SciTech Connect

    Guy, W.E.

    1988-09-27

    This patent describes the process of placing a string of tubing in an oil field well; a. the string of tubing when placed extending from the surface of the earth to an oil bearing formation far below the surface, b. the string made from i. a plurality of tubing sections, ii. each section having external threads on each end, and iii. cuffs with internal threads coupling the tubing sections together, c. each of the tubing sections having i. an axis, ii. a wall thickness, and iii. a corrosion resistant coating on its inside bore; wherein the improved method comprises: d. placing a section of tubing into the well with a cuff attached to the upper end at the surface of the earth, e. dropping a corrosion resistant nipple into the cuff, f. the nipple being loose in the cuff, g. attaching an additional section of tubing onto the cuff, and h. screwing the additional section tightly to the cuff.

  5. Corrosion studies with pixe

    NASA Astrophysics Data System (ADS)

    Anwar Chaudhri, M.; Crawford, A.

    1981-03-01

    To investigate the possible causes of corrosion of some of the tooth paste tubes of a major international cosmetic product manufacturer, the elemental compositions of corroded and clean unused tubes were compared, using PIXE. It was observed that some of the corroded tubes contained much higher amounts of Ti, Fe, Ga and Zn than the clean tubes, while the concentrations of Cr and Ni showed no significant difference between the two types of tubes. Only certain regions of one of the tubes were found to contain higher concentrations of Cu. Those regions were badly corroded and had the highest concentrations of Ti, Fe, Ga and Zn, too. It is suggested that the presence of higher amounts of Ti, Fe, Ga and Zn, and especially of Cu, in the aluminium sheets used to manufacture the tooth paste tubes, may be one of the reasons for the corrosion of some of the tooth paste tubes.

  6. CORROSION PROTECTION OF ALUMINUM

    DOEpatents

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  7. Corrosion Protection of Aluminum

    DOEpatents

    Dalrymple, R. S.; Nelson, W. B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred.

  8. Corrosion resistant coating

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  9. Corrosive resistant heat exchanger

    DOEpatents

    Richlen, Scott L.

    1989-01-01

    A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

  10. Stress Corrosion Testing

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Advanced testing of structural materials was developed by Lewis Research Center and Langley Research Center working with the American Society for Testing and Materials (ASTM). Under contract, Aluminum Company of America (Alcoa) conducted a study for evaluating stress corrosion cracking, and recommended the "breaking load" method which determines fracture strengths as well as measuring environmental degradation. Alcoa and Langley plan to submit the procedure to ASTM as a new testing method.

  11. Papering Over Corrosion

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Kennedy Space Center's battle against corrosion led to a new coating that was licensed to GeoTech and is commercially sold as Catize. The coating uses ligno sulfonic acid doped polyaniline (Ligno-Pani), also known as synthetic metal. Ligno-Pani can be used to extend the operating lives of steel bridges as one example of its applications. future applications include computers, televisions, cellular phones, conductive inks, and stealth technology.

  12. Corrosion resistant coating

    DOEpatents

    Wrobleski, D.A.; Benicewicz, B.C.; Thompson, K.G.; Bryan, C.J.

    1997-08-19

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  13. Evaluation of passivation method and corrosion inhibitors for steel-reinforced concrete structures

    NASA Astrophysics Data System (ADS)

    Brown, Richard; Lee, K. Wayne; Cao, Yong

    1999-02-01

    Corrosion of reinforcing steel due to the ingression of chloride ions from deicing salt and/or seawater has been a major cause of the deterioration of reinforced concrete structures. Typically reinforcing steel is protected from corrosion by the formation of passive film because of highly alkaline concrete environment. The film can be damaged with the introduction of chloride ions to concrete, then corrosion occurs. There are mainly three approaches to tackle this problem, i.e., protective coating, cathodic protection and corrosion inhibitors.

  14. Characterization of the corrosion resistance of biologically active solutions: The effects of anodizing and welding

    NASA Technical Reports Server (NTRS)

    Walsh, Daniel W.

    1991-01-01

    An understanding of fabrication processes, metallurgy, electrochemistry, and microbiology is crucial to the resolution of microbiologically influenced corrosion (MIC) problems. The object of this effort was to use AC impedance spectroscopy to characterize the corrosion resistance of Type II anodized aluminum alloy 2219-T87 in sterile and biologically active media and to examine the corrosion resistance of 316L, alloy 2219-T87, and titanium alloy 6-4 in the welded and unwelded conditions. The latter materials were immersed in sterile and biologically active media and corrosion currents were measured using the polarization resistance (DC) technique.

  15. Corrosive Resistant Diamond Coatings for the Acid Based Thermo-Chemical Hydrogen Cycles

    SciTech Connect

    Mark A. Prelas

    2009-06-25

    This project was designed to test diamond, diamond-like and related materials in environments that are expected in thermochemical cycles. Our goals were to build a High Temperature Corrosion Resistance (HTCR) test stand and begin testing the corrosive properties of barious materials in a high temperature acidic environment in the first year. Overall, we planned to test 54 samples each of diamond and diamond-like films (of 1 cm x 1 cm area). In addition we use a corrosion acceleration method by treating the samples at a temperature much larger than the expected operating temperature. Half of the samples will be treated with boron using the FEDOA process.

  16. Stress corrosion evaluation of powder metallurgy aluminum alloy 7091 with the breaking load test method

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.

    1987-01-01

    The stress corrosion behavior of the P/M aluminum alloy 7091 is evaluated in two overaged heat treatment conditions, T7E69 and T7E70, using an accelerated test technique known as the breaking load test method. The breaking load data obtained in this study indicate that P/M 7091 alloy is highly resistant to stress corrosion in both longitudinal and transverse orientations at stress levels up to 90 percent of the material yield strength. The reduction in mean breaking stress as a result of corrosive attack is smallest for the more overaged T7E70 condition. Details of the test procedure are included.

  17. Corrosion in supercritical fluids

    SciTech Connect

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  18. Corrosion detection by induction

    NASA Astrophysics Data System (ADS)

    Roddenberry, Joshua L.

    Bridges in Florida are exposed to high amounts of humidity due to the state's geography. This excess moisture results in a high incidence of corrosion on the bridge's steel support cables. Also, the inclusion of ineffective waterproofing has resulted in additional corrosion. As this corrosion increases, the steel cables, responsible for maintaining bridge integrity, deteriorate and eventually break. If enough of these cables break, the bridge will experience a catastrophic failure resulting in collapse. Repairing and replacing these cables is very expensive and only increases with further damage. As each of the cables is steel, they have strong conductive properties. By inducing a current along each group of cables and measuring its dissipation over distance, a picture of structural integrity can be determined. The purpose of this thesis is to prove the effectiveness of using electromagnetic techniques to determine cable integrity. By comparing known conductive values (determined in a lab setting) to actual bridge values, the tester will be able to determine the location and severity of any damage, if present.

  19. Compact accelerator

    DOEpatents

    Caporaso, George J.; Sampayan, Stephen E.; Kirbie, Hugh C.

    2007-02-06

    A compact linear accelerator having at least one strip-shaped Blumlein module which guides a propagating wavefront between first and second ends and controls the output pulse at the second end. Each Blumlein module has first, second, and third planar conductor strips, with a first dielectric strip between the first and second conductor strips, and a second dielectric strip between the second and third conductor strips. Additionally, the compact linear accelerator includes a high voltage power supply connected to charge the second conductor strip to a high potential, and a switch for switching the high potential in the second conductor strip to at least one of the first and third conductor strips so as to initiate a propagating reverse polarity wavefront(s) in the corresponding dielectric strip(s).

  20. Influence of chromium on the initial corrosion behavior of low alloy steels in the CO2-O2-H2S-SO2 wet-dry corrosion environment of cargo oil tankers

    NASA Astrophysics Data System (ADS)

    Zhao, Qing-he; Liu, Wei; Zhao, Jie; Zhang, Dong; Liu, Peng-cheng; Lu, Min-xu

    2015-08-01

    The influence of Cr on the initial corrosion behavior of low-alloy steels exposed to a CO2-O2-H2S-SO2 wet-dry corrosion environment was investigated using weight-loss measurements, scanning electron microscopy, N2 adsorption tests, X-ray diffraction analysis, and electrochemical impedance spectroscopy. The results show that the corrosion rate increases with increasing Cr content in samples subjected to corrosion for 21 d. However, the rust grain size decreases, its specific surface area increases, and it becomes more compact and denser with increasing Cr content, which indicates the enhanced protectivity of the rust. The results of charge transfer resistance ( R ct) calculations indicate that higher Cr contents can accelerate the corrosion during the first 7 d and promote the formation of the enhanced protective inner rust after 14 d; the formed protective inner rust is responsible for the greater corrosion resistance during long-term exposure.

  1. Corrosion inhibitors from expired drugs.

    PubMed

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%. PMID:22561212

  2. Protection of bronze artefacts through polymeric coatings based on nanocarriers filled with corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    de Luna, Martina Salzano; Buonocore, Giovanna; Di Carlo, Gabriella; Giuliani, Chiara; Ingo, Gabriel M.; Lavorgna, Marino

    2016-05-01

    Protective coatings based on polymers synthesized from renewable sources (chitosan or an amorphous vinyl alcohol based polymer) have been prepared for the protection of bronze artifacts from corrosion. Besides acting as an effective barrier against corrosive species present in the environment, the efficiency of the coatings has been improved by adding corrosion inhibitor compounds (benzotriazole or mercaptobenzothiazole) to the formulations. The liquid medium of the formulations has been carefully selected looking at maximizing the wettability on the bronze substrate and optimizing the solvent evaporation rate. The minimum amount of inhibitor compounds has been optimized by performing accelerated corrosion tests on coated bronze substrates. The inhibitors have been directly dissolved in the coating-forming solutions and/or introduced by means of nanocarriers, which allow to control the release kinetics. The free dissolved inhibitor molecules immediately provide a sufficient protection against corrosion. On the other hand, the inhibitor molecules contained in the nanocarriers serve as long-term reservoir, which can be activated by external corrosion-related stimuli in case of particularly severe conditions. Particular attention has been paid to other features which affect the coating performances. Specifically, the adhesion of the protective polymer layer to the bronze substrate has been assessed, as well as its permeability properties and transparency, the latter being a fundamental feature of protective coating for cultural heritages. Finally, the protective efficiency of the produced smart coatings has been assessed through accelerated corrosion tests.

  3. The growth of small corrosion fatigue cracks in alloy 2024

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Willard, Scott A.

    1993-01-01

    The corrosion fatigue crack growth characteristics of small surface and corner cracks in aluminum alloy 2024 is established. The damaging effect of salt water on the early stages of small crack growth is characterized by crack initiation at constituent particle pits, intergranular microcracking for a less than 100 micrometers, and transgranular small crack growth for a micrometer. In aqueous 1 percent NaCl and at a constant anodic potential of -700 mV(sub SCE), small cracks exhibit a factor of three increase in fatigue crack growth rates compared to laboratory air. Small cracks exhibit accelerated corrosion fatigue crack growth rates at low levels of delta-K (less than 1 MPa square root of m) below long crack delta-K (sub th). When exposed to Paris regime levels of crack tip stress intensity, small corrosion fatigue cracks exhibit growth rates similar to that observed for long cracks. Results suggest that crack closure effects influence the corrosion fatigue crack growth rates of small cracks (a less than or equal to 100 micrometers). This is evidenced by similar small and long crack growth behavior at various levels of R. Contrary to the corrosion fatigue characteristics of small cracks in high strength steels, no pronounced chemical crack length effect is observed for Al by 2024 exposed to salt water.

  4. Chlorine induced corrosion of steels in fossil fuel power plants

    SciTech Connect

    Spiegel, M.; Grabke, H.J.

    1998-12-31

    The corrosion of steels in power plants (coal combustion, waste incineration) is mainly due to condensed chlorides in the ash deposited on the boiler tubes. These chlorides are stabilized by HCl in the combustion gas. In the case of coal as a fuel, chlorine is present as chloride minerals in the raw material which is converted to HCl during the combustion process. Corrosion of steels in chlorine containing environments occurs by the active oxidation mechanism, which is a self-sustaining accelerated oxidation process, catalyzed by chlorine. This study shows that solid chlorides react with the oxide scale of the steels to form chlorine, which initiates active oxidation. In order to prevent chlorine induced corrosion, the deposition of chlorides on the tubes within the coal ash must be avoided. This is possible by the presence of SO{sub 2}, which is present in the combustion gas, converting the chlorides to sulfates in the gas phase. The paper presents an example of a failure case in a coal fired plant in Germany. In this plant, chlorine induced corrosion was observed after effective removal of SO{sub 2} by additions of CaO. From thermodynamic calculations it can be shown that a certain amount of SO{sub 2} is necessary in order to avoid deposition of chlorides and to prevent corrosion.

  5. Corrosion inhibitor evaluation for a gas compression system

    SciTech Connect

    Perdomo, J.J.; Ramirez, M.; Viloria, A.; Morales, J.L.

    1999-11-01

    The injection of chemicals for gas systems is a common practice to prevent corrosion and asphaltene deposition. A laboratory study was conducted to evaluate 5 commercially available corrosion inhibitors and an asphaltene dispersant for a gas compression plant. This study was set out to look at the compatibility of a pipeline corrosion inhibitor with both an anti asphaltene and a gas compression inhibitor which is required to have a relatively large flammable point and resist the pressure and temperature of the process without igniting or aging. Also, the effect of precorroded surfaces was studied to establish its effect on the performance of the pipeline inhibitor. The efficiency of the products was evaluated through either coupon weight loss tests or polarization resistance. Corrosion inhibitor aging was carried out in autoclaves emulating operating conditions, subsequently, gel permeation chromatography (GPC), total nitrogen and viscosity measurements were performed on the products before and after aging to establish the variation of their physical and chemical properties. Additionally, X-ray diffraction analysis (XRD) and energy dispersion spectroscopy (EDS) were used to identify corrosion products. From the study, an efficiency of 86% was obtained for a line inhibitor at a 45-PPM dosage (at 36 psi pCO{sub 2} and 0.006 psi of H{sub 2}S at 120 F), lowering its efficiency to 76% after precorroding the surface for three days. The presence of asphaltene may reduce the corrosion rate; however, the injection of a dispersant accelerates the corrosion process. No significant changes in efficiency and physical properties were observed during the evaluation of one of the compression-line inhibitor mixtures tested.

  6. Corrosion studies in fuel element reprocessing environments containing nitric acid

    SciTech Connect

    Beavers, J A; White, R R; Berry, W E; Griess, J C

    1982-04-01

    Nitric acid is universally used in aqueous fuel element reprocessing plants; however, in the processing scheme being developed by the Consolidated Fuel Reprocessing Program, some of the equipment will be exposed to nitric acid under conditions not previously encountered in fuel element reprocessing plants. A previous report presented corrosion data obtained in hyperazeotropic nitric acid and in concentrated magnesium nitrate solutions used in its preparation. The results presented in this report are concerned with the following: (1) corrosion of titanium in nitric acid; (2) corrosion of nickel-base alloys in a nitric acid-hydrofluoric acid solution; (3) the formation of Cr(VI), which enhances corrosion, in nitric acid solutions; and (4) corrosion of mechanical pipe connectors in nitric acid. The results show that the corrosion rate of titanium increased with the refreshment rate of boiling nitric acid, but the effect diminished rapidly as the temperature decreased. The addition of iodic acid inhibited attack. Also, up to 200 ppM of fluoride in 70% HNO/sub 3/ had no major effect on the corrosion of either titanium or tantalum. In boiling 8 M HNO/sub 3/-0.05 M HF, Inconel 671 was more resistant than Inconel 690, but both alloys experienced end-grain attack. In the case of Inconel 671, heat treatment was very important; annealed and quenched material was much more resistant than furnace-cooled material.The rate of oxidation of Cr(III) to Cr(VI) increased significantly as the nitric acid concentration increased, and certain forms of ruthenium in the solution seemed to accelerate the rate of formation. Mechanical connectors of T-304L stainless steel experienced end-grain attack on the exposed pipe ends, and seal rings of both stainless steel and a titanium alloy (6% Al-4% V) underwent heavy attack in boiling 8 M HNO/sub 3/.

  7. Home Plumbing Simulator for the Study of Copper and Lead Corrosion and Release, Disinfectant Demand, and Biofilm Activity - abstract

    EPA Science Inventory

    The corrosion of household or premise plumbing materials (such as copper, brass, and solder) and the metal release that results from that corrosion can cause numerous problems, ranging from “blue” water to copper pinhole leaks. If left untreated, these problems can lead to health...

  8. BICEP's acceleration

    SciTech Connect

    Contaldi, Carlo R.

    2014-10-01

    The recent Bicep2 [1] detection of, what is claimed to be primordial B-modes, opens up the possibility of constraining not only the energy scale of inflation but also the detailed acceleration history that occurred during inflation. In turn this can be used to determine the shape of the inflaton potential V(φ) for the first time — if a single, scalar inflaton is assumed to be driving the acceleration. We carry out a Monte Carlo exploration of inflationary trajectories given the current data. Using this method we obtain a posterior distribution of possible acceleration profiles ε(N) as a function of e-fold N and derived posterior distributions of the primordial power spectrum P(k) and potential V(φ). We find that the Bicep2 result, in combination with Planck measurements of total intensity Cosmic Microwave Background (CMB) anisotropies, induces a significant feature in the scalar primordial spectrum at scales k∼ 10{sup -3} Mpc {sup -1}. This is in agreement with a previous detection of a suppression in the scalar power [2].

  9. Ultimate strength performance of tankers associated with industry corrosion addition practices

    NASA Astrophysics Data System (ADS)

    Kim, Do Kyun; Kim, Han Byul; Zhang, Xiaoming; Li, Chen Guang; Paik, Jeom Kee

    2014-09-01

    In the ship and offshore structure design, age-related problems such as corrosion damage, local denting, and fatigue damage are important factors to be considered in building a reliable structure as they have a significant influence on the residual structural capacity. In shipping, corrosion addition methods are widely adopted in structural design to prevent structural capacity degradation. The present study focuses on the historical trend of corrosion addition rules for ship structural design and investigates their effects on the ultimate strength performance such as hull girder and stiffened panel of double hull oil tankers. Three types of rules based on corrosion addition models, namely historic corrosion rules (pre-CSR), Common Structural Rules (CSR), and harmonised Common Structural Rules (CSRH) are considered and compared with two other corrosion models namely UGS model, suggested by the Union of Greek Shipowners (UGS), and Time-Dependent Corrosion Wastage Model (TDCWM). To identify the general trend in the effects of corrosion damage on the ultimate longitudinal strength performance, the corrosion addition rules are applied to four representative sizes of double hull oil tankers namely Panamax, Aframax, Suezmax, and VLCC. The results are helpful in understanding the trend of corrosion additions for tanker structures

  10. Recent developments in wear and corrosion resistant alloys for oil industry

    SciTech Connect

    Raghu, D.; Wu, J.B.C.

    1997-08-01

    Oil production and refining environments pose a very severe wear and corrosion environment. Material designers are challenged with the need to design and develop materials that combine a high corrosion resistance with very good wear resistance. Coupled with that is the need for these materials to meet requirements, such as, fracture toughness and resistance to sulfide and chloride stress corrosion cracking. Often times, increasing the resistance to wear compromises the corrosion and welding characteristics. This paper covers a variety of material developments that aim to address the twin problems of wear and corrosion. The paper covers the alloy design fundamentals and discusses the pertinent wear properties and general corrosion resistance compared to traditional wear resistant materials. Proven applications, with particular reference to petroleum and petro-chemical areas are discussed. Potential applications are also cited.

  11. Visualizing Nanoscale Distribution of Corrosion Cells by Open-Loop Electric Potential Microscopy.

    PubMed

    Honbo, Kyoko; Ogata, Shoichiro; Kitagawa, Takuya; Okamoto, Takahiro; Kobayashi, Naritaka; Sugimoto, Itto; Shima, Shohei; Fukunaga, Akira; Takatoh, Chikako; Fukuma, Takeshi

    2016-02-23

    Corrosion is a traditional problem but still one of the most serious problems in industry. To reduce the huge economic loss caused by corrosion, tremendous effort has been made to understand, predict and prevent it. Corrosion phenomena are generally explained by the formation of corrosion cells at a metal-electrolyte interface. However, experimental verification of their nanoscale distribution has been a major challenge owing to the lack of a method able to visualize the local potential distribution in an electrolytic solution. In this study, we have investigated the nanoscale corrosion behavior of Cu fine wires and a duplex stainless steel by in situ imaging of local corrosion cells by open-loop electric potential microscopy (OL-EPM). For both materials, potential images obtained by OL-EPM show nanoscale contrasts, where areas of higher and lower potential correspond to anodic areas (i.e., corrosion sites) and cathodic areas, respectively. This imaging capability allows us to investigate the real-time transition of local corrosion sites even when surface structures show little change. This is particularly useful for investigating reactions under surface oxide layers or highly corrosion-resistant materials as demonstrated here. The proposed technique should be applicable to the study of other redox reactions on a battery electrode or a catalytic material. The results presented here open up such future applications of OL-EPM in nanoscale electrochemistry. PMID:26811989

  12. Datum definition problems in accelerator alignment

    SciTech Connect

    Bell, B.; Friedsam, H.; Oren, W.; Ruland, R.

    1990-04-01

    Any measurement task requires a fixed reference base (the datum) from which measurements can be made and calculated. The linac was the datum to which all SLC components were aligned; although this reference existed as a physical object, the actual establishment of the datum and its transferral to datums that were more useful for the SLC installation challenged the technology and computational ability of the survey group. Once established, the maintenance of datums is not to be taken for granted, as demonstrated by the 1989 earthquake which destroyed all SLAC's survey datums. 7 refs., 6 figs.

  13. Theoretical problems in accelerator physics. Progress report

    SciTech Connect

    Not Available

    1994-08-01

    This is the second progress report submitted under the author`s current grant and covers progress made since the submission of the first progress report in August 1993. During this period the author has continued to spend approximately one half of his time at SLAC and most of the projects reported here were carried out in collaboration with individuals and groups at SLAC. Except where otherwise noted, reference numbers in the text refer to the attached list of current contract publications. Copies of the publications, numbered in agreement with the publication list, are included with this report.

  14. Positive grid corrosion elongation analysis using CAE with corrosion deformation transformed into thermal phenomenon

    NASA Astrophysics Data System (ADS)

    Mukaitani, Ichiroh; Hayashi, Koji; Shimoura, Ichiro; Takemasa, Arihiko; Takahashi, Isamu; Tsubakino, Harushige

    Valve-regulated lead-acid (VRLA) batteries have been commercially available for more than 20 years and have been enthusiastically embraced by users of uninterruptible power supplies (UPS) because of the anticipated reduction in installation and operating costs, smaller footprint and fewer environmental concerns. In Japan, communication networks are demanding reduced costs and longer life from their batteries. Among the factors limiting the life of VRLA batteries, the corrosion of positive grid material has been proven to cause elongation of the plates, loss of electrical contact and shorter lifetime. The content of Sn is also a key factor and addition of Sn in the grid alloy results in better performance in creep resistance, tensile strength and corrosion resistance [R. David Prenagaman, The Battery Man, vol. 39, September 1997, p. 16. I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. A key point is what the ratio of Sn to Ca should be, since too much Sn may lead to even worse elongation of the plates [I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. We have determined that microstructure control with a composition of lead-calcium-tin (Pb-Ca-Sn) alloy is optimal for better performance of the plates [I. Mukaitani, T. Sakamoto, T. Kikuoka, Y. Yamaguchi, H. Tsubakino, Proceedings of the 40th Battery Symposium in Japan, 1999, p. 99]. We developed a "simulation of current collector corrosion elongation" which is a technique of estimating corrosion elongation from the current collector design [I. Mukaitani, K. Hayashi, I. Shimoura, H. Takabayashi, M. Terada, A. Takemasa, I. Takahashi, K. Okamoto, Proceedings of the 44th Battery Symposium in Japan, 2003, p. 652]. Corrosion elongation occurs as the corrosion material layer grows out of the current collector metal. We resolved this problem using generally CAD

  15. 49 CFR 172.558 - CORROSIVE placard.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SECURITY PLANS Placarding § 172.558 CORROSIVE placard. (a) Except for size and color, the CORROSIVE placard... the CORROSIVE placard must be black in the lower portion with a white triangle in the upper...

  16. 49 CFR 172.558 - CORROSIVE placard.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SECURITY PLANS Placarding § 172.558 CORROSIVE placard. (a) Except for size and color, the CORROSIVE placard... the CORROSIVE placard must be black in the lower portion with a white triangle in the upper...

  17. Advanced concepts for acceleration

    SciTech Connect

    Keefe, D.

    1986-07-01

    Selected examples of advanced accelerator concepts are reviewed. Such plasma accelerators as plasma beat wave accelerator, plasma wake field accelerator, and plasma grating accelerator are discussed particularly as examples of concepts for accelerating relativistic electrons or positrons. Also covered are the pulsed electron-beam, pulsed laser accelerator, inverse Cherenkov accelerator, inverse free-electron laser, switched radial-line accelerators, and two-beam accelerator. Advanced concepts for ion acceleration discussed include the electron ring accelerator, excitation of waves on intense electron beams, and two-wave combinations. (LEW)

  18. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-12-31

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  19. Accelerator physics and modeling: Proceedings

    SciTech Connect

    Parsa, Z.

    1991-01-01

    This report contains papers on the following topics: Physics of high brightness beams; radio frequency beam conditioner for fast-wave free-electron generators of coherent radiation; wake-field and space-charge effects on high brightness beams. Calculations and measured results for BNL-ATF; non-linear orbit theory and accelerator design; general problems of modeling for accelerators; development and application of dispersive soft ferrite models for time-domain simulation; and bunch lengthening in the SLC damping rings.

  20. Review of corrosion in 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders

    SciTech Connect

    Lykins, M.L.

    1995-08-01

    A literature review was conducted to determine the type, extent and severity of corrosion found in the 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders. Also discussed in this review is corrosion found in the valves and plugs used in the cylinders. Corrosion of the cylinders is a gradual process which occurs slowly over time. Understanding corrosion of the cylinders is an important concern for long term storage of the UF{sub 6} in the cylinder yards, as well as the final disposition of the depleted UF{sub 6} tails inventory in the future. The following conclusions are made from the literature review: (1) The general external corrosion rate of the cylinders is about 1 to 2 mils per year (1 mil = 0.001{double_prime}). The highest general external corrosion rate was over 5 mpy on the 48G type cylinders. (2) General internal corrosion from the depleted UF{sub 6} is negligible under normal storage conditions. Crevice corrosion can occur at the cylinder/saddle interface from the retention of water in this area. Crevice corrosion can occur at the cylinder/skirt interface on the older skirted cylinders due to the lack of water drainage in this area. Crevice corrosion can occur on cylinders that have been in ground contact. Crevice corrosion and galvanic corrosion can occur where the stainless steel I.D. nameplates are attached to the cylinder. The packing nuts on the bronze one-inch valves used in the cylinders are susceptible to stress corrosion cracking (SCC). Mechanical damage from routine handling can lead to a breach in a cylinder with subsequent accelerated corrosion of the mild steel due to attack from HF and other UF{sub 6} hydrolysis by-products.

  1. Microencapsulation of Self Healing Agents for Corrosion Control Coatings

    NASA Technical Reports Server (NTRS)

    Jolley, S. T.; Li, W.; Buhrow, J. W.; Calle, L. M.

    2011-01-01

    Corrosion, the environmentally induced degradation of materials, is a very costly problem that has a major impact on the global economy. Results from a 2-year breakthrough study released in 2002 by the U.S. Federal Highway Administration (FHWA) showed that the total annual estimated direct cost associated with metallic corrosion in nearly every U.S. industry sector was a staggering $276 billion, approximately 3.1% of the nation's Gross Domestic Product (GOP). Corrosion protective coatings are widely used to protect metallic structures from the detrimental effects of corrosion but their effectiveness can be seriously compromised by mechanical damage, such as a scratch, that exposes the metallic substrate. The incorporation of a self healing mechanism into a corrosion control coating would have the potential to significantly increase its effectiveness and useful lifetime. This paper describes work performed to incorporate a number of microcapsule-based self healing systems into corrosion control coatings. The work includes the preparation and evaluation of self-healing systems based on curable epoxy, acrylate, and siloxane resins, as well as, microencapsulated systems based on passive, solvent born, healing agent delivery. The synthesis and optimization of microcapsule-based self healing systems for thin coating (less than 100 micron) will be presented.

  2. Control of fractionation-area corrosion at SRC pilot plants

    SciTech Connect

    Keiser, J.R.; Judkins, R.R.; Baylor, V.B.; Canfield, D.R.; Barnett, W.P.

    1981-10-01

    Fractionating columns at the Fort Lewis, Washington, and Wilsonville, Alabama, Solvent Refined Coal pilot plants have experienced severe corrosion. This corrosion is most serious for materials exposed in the 230 to 250/sup 0/C (446 to 482/sup 0/F) range. Corrosion rates as high as 25 mm/year (1000 mils/year) on carbon steel and 6.4 mm/year (250 mils/year) on type 18-8 stainless steels have been observed. This corrosion problem has been studied at ORNL through exposure of coupons in the columns, analysis of failed components from the pilot plants, chemical analysis of liquids from the pilot plants, and operation of laboratory experiments. The in-plant exposure of coupons has shown that certain nickel-base alloys have adequate corrosion resistance for the environment. Chemical analyses of pilot plant liquids have shown that the presence of appreciable levels of water-soluble chloride is a necessary but not sufficient condition for these oils to be corrosive. By analysis of Fort Lewis and Wilpaw Shale (Kb), Fox Hills Sandstone (Kfh), and the Hell Creek formation (Khc). Anomaly No. 31 is over an area underlain by Recent alluvium (Qal).

  3. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    SciTech Connect

    Wiersma, B.

    2011-08-24

    the agitated and non-agitated solution were 2 mils/day and 1 mil/day, respectively. A mechanism by which the mercury interacts with the aluminum and silicon oxides in this simulant to accelerate corrosion was proposed.

  4. EROSION OF ELEVATED TEMPERATURE CORROSION SCALES ON METALS

    SciTech Connect

    Maasberg, J.A.; Levy, A.V.

    1981-05-01

    Combined erosion-corrosion poses a considerable problem to the design of long lifetime metallic components in energy conversion systems. To gain some insight into this problem, scales were formed on stainless steel at elevated temperature and subsequently were eroded at room temperature to determine the nature of the erosion rates and the mechanism of scale removal. Thin corrosion scales were formed on 310 stainless steel and an experimental Fe-18Cr-5Al-1Hf alloy at high temperatures (9ooo and 980°C) in gas mixtures with various levels of oxygen and combined oxygen-sulfur. The corroded specimens were eroded at room temperature in an air-solid particle stream using 50{micro}m SiC at 60 ms{sup -1}. The conditions of the corrosive exposures, the rates of erosion of these scales and the microscopic appearance of the eroded surface were correlated to determine the mechanism of thin scale erosion.

  5. Corrosion and fatigue of surgical implants

    NASA Technical Reports Server (NTRS)

    Lisagor, W. B.

    1975-01-01

    Implants for the treatment of femoral fractures, mechanisms leading to the failure or degradation of such structures, and current perspectives on surgical implants are discussed. Under the first heading, general usage, materials and procedures, environmental conditions, and laboratory analyses of implants after service are considered. Corrosion, crevice corrosion, stress corrosion cracking, intergranular corrosion, pitting corrosion, fatigue, and corrosion fatigue are the principal degradation mechanisms described. The need for improvement in the reliability of implants is emphasized.

  6. Accelerators and the Accelerator Community

    SciTech Connect

    Malamud, Ernest; Sessler, Andrew

    2008-06-01

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  7. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    PubMed Central

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys. PMID:26615896

  8. CURRENT CORROSION BY-PRODUCTS AND CORROSION CONTROL RESEARCH

    EPA Science Inventory

    USEPA research in the area of corrosion control consists of a combination of in-house research and extramural projects. he extramural projects have recently addressed the corrosion of solder in some Long Island water supplies, impacts of municipal ion-exchange softening on corros...

  9. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion.

    PubMed

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys. PMID:26615896

  10. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    NASA Astrophysics Data System (ADS)

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K.

    2015-11-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

  11. Experimental Design for the Evaluation of Detection Techniques of Hidden Corrosion Beneath the Thermal Protective System of the Space Shuttle Orbiter

    NASA Technical Reports Server (NTRS)

    Kammerer, Catherine C.; Jacoby, Joseph A.; Lomness, Janice K.; Hintze, Paul E.; Russell, Richard W.

    2007-01-01

    The United States Space Operational Space Shuttle Fleet Consists of three shuttles with an average age of 19.7 years. Shuttles are exposed to corrosive conditions while undergoing final closeout for missions at the launch pad and extreme conditions during ascent, orbit, and descent that may accelerate the corrosion process. Structural corrosion under TPS could progress undetected (without tile removal) and eventually result in reduction in structural capability sufficient to create negative margins of . safety and ultimate loss of local structural capability.

  12. Mechanism of corrosion inhibition of AA2024 by rare-earth compounds.

    PubMed

    Yasakau, Kiryl A; Zheludkevich, Mikhail L; Lamaka, Sviatlana V; Ferreira, Mario G S

    2006-03-23

    The mechanism of corrosion protection of the widely used 2024-T3 aluminum alloy by cerium and lanthanum inhibitors in chloride media is described in detail in the present work. The corrosion process was investigated by means of scanning Kelvin probe force microscopy (SKPFM), in situ atomic force microscopy, and scanning electron microscopy coupled with energy dispersive spectroscopy. Employment of the high-resolution and in situ techniques results in a deep understanding of the details of the physical chemistry and mechanisms of the corrosion processes. The applicability of the SKPFM for mechanistic analysis of the effect of different corrosion inhibitors is demonstrated for the first time. The inhibitors under study show sufficient hindering of the localized corrosion processes especially in the case of pitting formation located around the intermetallic S-phase particles. The main role of Ce(3+) and La(3+) in the corrosion protection is formation of hydroxide deposits on S-phase inclusions buffering the local increase of pH, which is responsible for the acceleration of the intermetallics dealloying. The formed hydroxide precipitates can also act as a diffusion barrier hindering the corrosion processes in active zones. Cerium nitrate exhibits higher inhibition efficiency in comparison with lanthanum nitrate. The higher effect in the case of cerium is obtained due to lower solubility of the respective hydroxide. A detailed mechanism of the corrosion process and its inhibition is proposed based on thermodynamic analysis. PMID:16539491

  13. Microbial corrosion of stainless steel.

    PubMed

    Ibars, J R; Moreno, D A; Ranninger, C

    1992-11-01

    Stainless steel, developed because of their greater resistance to corrosion in different aggressive environments, have proved to be affected, however, by various processes and types of corrosion. Some of these types of corrosion, mainly pitting, is activated and developed in the presence of microorganisms, which acting in an isolated or symbiotic way, according to their adaptation to the environment, create a favorable situation for the corrosion of these steel. The microorganisms that are involved, mainly bacteria of both the aerobic and anaerobic type, modify the environment where the stainless steel is found, creating crevices, differential aeration zones or a more aggressive environment with the presence of metabolites. In these circumstances, a local break of the passive and passivating layer is produced, which is proper to these types of steel and impedes the repassivation that is more favorable to corrosion. In the study and research of these types of microbiologically influenced corrosion are found electrochemical techniques, since corrosion is fundamentally an electrochemical process, and microbiological techniques for the identification, culture, and evaluation of the microorganisms involved in the process, as well as in the laboratory or field study of microorganism-metal pairs. Microstructural characterization studies of stainless steel have also been considered important, since it is known that the microstructure of steel can substantially modify their behavior when faced with corrosion. As for surface analysis studies, it is known that corrosion is a process that is generated on and progresses from the surface. The ways of dealing with microbiologically influenced corrosion must necessarily include biocides, which are not always usable or successful, the design of industrial equipment or components that do not favor the adherence of microorganisms, using microstructures in steel less sensitive to corrosion, or protecting the materials. PMID:1492953

  14. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    SciTech Connect

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  15. Aircraft crash caused by stress corrosion cracking

    SciTech Connect

    Kolkman, H.J.; Kool, G.A.; Wanhill, R.J.H.

    1996-01-01

    An aircraft crash in the Netherlands was caused by disintegration of a jet engine. Fractography showed that the chain of events started with stress corrosion cracking (SCC) of a pin attached to a lever arm of the compressor variable vane system. Such a lever arm-pin assembly costs only a few dollars. Investigation of hundreds of pins from the accident and a number of identical engines revealed that this was not an isolated case. Many pins exhibited various amounts of SCC. The failed pin in the accident engine happened to be the first fractured one. SCC requires the simultaneous presence of tensile stress, a corrosive environment, and a susceptible material. In this case the stress was a residual stress arising from the production method. There was a clear correlation between the presence of salt deposits on the levers and SCC of the pins. It was shown that these deposits were able to reach the internal space between the pin and lever arm, thereby initiating SCC in this space. The corrosive environment in Western Europe explains why the problem manifested itself in the Netherlands at a relatively early stage in engine life. The main point is, however, that the manufacturer selected an SCC-prone material in the design stage. The solution has been to change the pin material.

  16. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings Evaluation of Corrosion Reistance FY05 HPCRM Annual Report # Rev. 1DOE-DARPA Co-Sponsored Advanced Materials Program

    SciTech Connect

    Farmer, J C; Haslam, J J; Day, S D

    2007-09-19

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  17. Corrosion of Ceramic Materials

    NASA Technical Reports Server (NTRS)

    Opila, Elizabeth J.; Jacobson, Nathan S.

    1999-01-01

    Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

  18. INHIBITION OF CORROSION

    DOEpatents

    Atherton, J.E. Jr.; Gurinsky, D.H.

    1958-06-24

    A method is described for preventing corrosion of metallic container materials by a high-temperature liquid bismuth flowing therein. The method comprises fabricating the containment means from a steel which contains between 2 and 12% chromium, between 0.5 and 1.5% of either molybdenum and silicon, and a minimum of nickel and manganese, and maintaining zirconium dissolved in the liquid bismuth at a concentration between 50 parts per million and its saturation value at the lowest temperature in the system.

  19. Vacuum Ampoule Isolates Corrosive Materials

    NASA Technical Reports Server (NTRS)

    Crouch, R. K.; Debnam, W. J.; Taylor, R.

    1983-01-01

    Quartz vacuum ampoule confines corrosive sample wafer between two quartz plugs inserted in quartz tube. One quartz plug is window for measuring sample thermodynamic properties while laser pulse entering other quartz plug heats sample to molten state. Confinement of sample in vacuum prevents contamination of measurement system by hot corrosive vapors and any interference by preferential evaporation of melt.

  20. Atlas 5013 tank corrosion test

    NASA Technical Reports Server (NTRS)

    Sutherland, W. M.; Girton, L. D.; Treadway, D. G.

    1978-01-01

    The type and cause of corrosion in spot welded joints were determined by X-ray and chemical analysis. Fatigue and static tests showed the degree of degradation of mechanical properties. The corrosion inhibiting effectiveness of WD-40 compound and required renewal period by exposing typical joint specimens were examined.

  1. Agricultural Polymers as Corrosion Inhibitors

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural polymers were composed of extra-cellular polysaccharides secreted by Leuconostoc mesenteroides have been shown to inhibit corrosion on corrosion-sensitive metals. The substantially pure exopolysaccharide has a general structure consisting of alpha(1-6)-linked D-glucose backbone and appr...

  2. DPC materials and corrosion environments.

    SciTech Connect

    Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest; Clarity, J.

    2014-10-01

    After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

  3. Characterization of Copper Corrosion Products Formed in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  4. Characterization of Copper Corrosion Products in Drinking Water by Combining Electrochemical and Surface Analyses

    EPA Science Inventory

    This study focuses on the application of electrochemical approaches to drinking water copper corrosion problems. Applying electrochemical approaches combined with copper solubility measurements, and solid surface analysis approaches were discussed. Tafel extrapolation and Electro...

  5. Suppressing Parasitic Effects in a Long Dielectric Wakefield Accelerator

    SciTech Connect

    Shchegolkov, Dmitry; Simakov, Evgenya Ivanovna; Jing, Chunguang; Li, Chen; Zholents, Alexander A.; Power, John G.

    2014-08-27

    Dielectric wakefield acceleration is a promising concept for increasing the accelerating gradient above the limits of conventional accelerators. Although superior gradients are reported in short dielectric wakefield accelerator tubes, problems arise when it comes to efficiency and multi-meter long interaction lengths. Here we discuss possible issues and provide some solutions backed by simulations.

  6. FY05 HPCRM Annual Report: High-Performance Corrosion-Resistant Iron-Based Amorphous Metal Coatings

    SciTech Connect

    Farmer, J; Choi, J; Haslam, J; Day, S; Yang, N; Headley, T; Lucadamo, G; Yio, J; Chames, J; Gardea, A; Clift, M; Blue, G; Peters, W; Rivard, J; Harper, D; Swank, D; Bayles, R; Lemieux, E; Brown, R; Wolejsza, T; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Aprigliano, L; Branagan, D; Marshall, M; Meacham, B; Lavernia, E; Schoenung, J; Ajdelsztajn, L; Dannenberg, J; Graeve, O; Lewandowski, J; Perepezko, J; Hildal, K; Kaufman, L; Boudreau, J

    2007-09-20

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative corrosion resistance. Many of these materials can be applied as coatings with advanced thermal spray technology. Two compositions have corrosion resistance superior to wrought nickel-based Alloy C-22 (UNS No. N06022) in some very aggressive environments, including concentrated calcium-chloride brines at elevated temperature. Two Fe-based amorphous metal formulations have been found that appear to have corrosion resistance comparable to, or better than that of Ni-based Alloy C-22, based on breakdown potential and corrosion rate. Both Cr and Mo provide corrosion resistance, B enables glass formation, and Y lowers critical cooling rate (CCR). SAM1651 has yttrium added, and has a nominal critical cooling rate of only 80 Kelvin per second, while SAM2X7 (similar to SAM2X5) has no yttrium, and a relatively high critical cooling rate of 610 Kelvin per second. Both amorphous metal formulations have strengths and weaknesses. SAM1651 (yttrium added) has a low critical cooling rate (CCR), which enables it to be rendered as a completely amorphous thermal spray coating. Unfortunately, it is relatively difficult to atomize, with powders being irregular in shape. This causes the powder to be difficult to pneumatically convey during thermal spray deposition. Gas atomized SAM1651 powder has required cryogenic milling to eliminate irregularities that make flow difficult. SAM2X5 (no yttrium) has a high critical cooling rate, which has caused problems associated with devitrification. SAM2X5 can be gas atomized to produce spherical powders of SAM2X5, which enable more facile thermal spray deposition. The reference material, nickel-based Alloy C-22, is an outstanding corrosion-resistant engineering material. Even so, crevice corrosion has been observed with C-22 in hot sodium chloride environments without buffer

  7. Electrochemical studies of corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  8. Corrosion of Titanium Matrix Composites

    SciTech Connect

    Covino, B.S., Jr.; Alman, D.E.

    2002-09-22

    The corrosion behavior of unalloyed Ti and titanium matrix composites containing up to 20 vol% of TiC or TiB{sub 2} was determined in deaerated 2 wt% HCl at 50, 70, and 90 degrees C. Corrosion rates were calculated from corrosion currents determined by extrapolation of the tafel slopes. All curves exhibited active-passive behavior but no transpassive region. Corrosion rates for Ti + TiC composites were similar to those for unalloyed Ti except at 90 degrees C where the composites were slightly higher. Corrosion rates for Ti + TiB{sub 2} composites were generally higher than those for unalloyed Ti and increased with higher concentrations of TiB{sub 2}. XRD and SEM-EDS analyses showed that the TiC reinforcement did not react with the Ti matrix during fabrication while the TiB{sub 2} reacted to form a TiB phase.

  9. 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...

  10. Residual contamination and corrosion on electrochemically marked uranium

    SciTech Connect

    Seals, R.D.; Bullock, J.S.; Bennett, R.K.

    1981-01-01

    Residual contamination and potential corrosion problems on uranium parts resulting from PHB-1 and PHB-1E electroetchants have been investigated using ion microprobe mass analysis (IMMA), scanning electron microscopy (SEM), and light microscopy (LM). The effectiveness of various solvent cleaning sequences and the influence of the use of an abrasive cleaner were evaluated. The marking thicknesses and chlorine distributions were determined.

  11. Naval electrochemical corrosion reducer

    DOEpatents

    Clark, Howard L.

    1991-10-01

    A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.

  12. IN DRIFT CORROSION PRODUCTS

    SciTech Connect

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  13. Accelerator system and method of accelerating particles

    NASA Technical Reports Server (NTRS)

    Wirz, Richard E. (Inventor)

    2010-01-01

    An accelerator system and method that utilize dust as the primary mass flux for generating thrust are provided. The accelerator system can include an accelerator capable of operating in a self-neutralizing mode and having a discharge chamber and at least one ionizer capable of charging dust particles. The system can also include a dust particle feeder that is capable of introducing the dust particles into the accelerator. By applying a pulsed positive and negative charge voltage to the accelerator, the charged dust particles can be accelerated thereby generating thrust and neutralizing the accelerator system.

  14. Attention's Accelerator.

    PubMed

    Reinhart, Robert M G; McClenahan, Laura J; Woodman, Geoffrey F

    2016-06-01

    How do people get attention to operate at peak efficiency in high-pressure situations? We tested the hypothesis that the general mechanism that allows this is the maintenance of multiple target representations in working and long-term memory. We recorded subjects' event-related potentials (ERPs) indexing the working memory and long-term memory representations used to control attention while performing visual search. We found that subjects used both types of memories to control attention when they performed the visual search task with a large reward at stake, or when they were cued to respond as fast as possible. However, under normal circumstances, one type of target memory was sufficient for slower task performance. The use of multiple types of memory representations appears to provide converging top-down control of attention, allowing people to step on the attentional accelerator in a variety of high-pressure situations. PMID:27056975

  15. Higher temperature coal tar enamel fights corrosion

    SciTech Connect

    Johnson, J.R.; Henegar, S.; Roder, B.

    1996-10-01

    High temperatures create new challenges for pipeline coatings. Cracking, adhesion breakdown and electrochemical corrosion are accelerated by higher service temperatures. A new epoxy primer/coal tar pipeline coating system utilizes the latent heat of the coal tar application to fully cure the newly developed primer to achieve outstanding bonding integrity and high temperature cathodic disbondment resistance. A key reason for this overall high performance is the marriage of a newly developed epoxy primer that provides outstanding adhesion with coal tar enamel, which provides excellent long-term water resistance. The paper describes experimental studies, pilot plant application, cathodic disbondment testing, and results from hot water soak tests and the low temperature cracking test.

  16. Molten salt corrosion of SiC and Si3N4

    NASA Technical Reports Server (NTRS)

    Jacobson, N. S.; Smialek, J. L.; Fox, D. S.

    1986-01-01

    The most severe type of corrosion encountered in heat engines is corrosion by molten sodium sulfate, formed by the reaction of ingested sodium chloride and sulfur impurities in the fuel. This problem was studied extensively for superalloys, but only recently examined for ceramics. This problem is addressed with laboratory studies to understand the fundamental reaction mechanisms and with burner studies to provide a more realistic simulation of the conditions encountered in a heat engine. In addition the effect of corrosion on the strengths of these materials was assessed. Each of these aspects will be reviewed and some ideas toward possible solutions will be discussed.

  17. Thermally oxidized titania nanotubes enhance the corrosion resistance of Ti6Al4V.

    PubMed

    Grotberg, John; Hamlekhan, Azhang; Butt, Arman; Patel, Sweetu; Royhman, Dmitry; Shokuhfar, Tolou; Sukotjo, Cortino; Takoudis, Christos; Mathew, Mathew T

    2016-02-01

    The negative impact of in vivo corrosion of metallic biomedical implants remains a complex problem in the medical field. We aimed to determine the effects of electrochemical anodization (60V, 2h) and thermal oxidation (600°C) on the corrosive behavior of Ti-6Al-4V, with serum proteins, at physiological temperature. Anodization produced a mixture of anatase and amorphous TiO2 nanopores and nanotubes, while the annealing process yielded an anatase/rutile mixture of TiO2 nanopores and nanotubes. The surface area was analyzed by the Brunauer-Emmett-Teller method and was estimated to be 3 orders of magnitude higher than that of polished control samples. Corrosion resistance was evaluated on the parameters of open circuit potential, corrosion potential, corrosion current density, passivation current density, polarization resistance and equivalent circuit modeling. Samples both anodized and thermally oxidized exhibited shifts of open circuit potential and corrosion potential in the noble direction, indicating a more stable nanoporous/nanotube layer, as well as lower corrosion current densities and passivation current densities than the smooth control. They also showed increased polarization resistance and diffusion limited charge transfer within the bulk oxide layer. The treatment groups studied can be ordered from greatest corrosion resistance to least as Anodized+Thermally Oxidized > Anodized > Smooth > Thermally Oxidized for the conditions investigated. This study concludes that anodized surface has a potential to prevent long term implant failure due to corrosion in a complex in-vivo environment. PMID:26652422

  18. Condenser tube erosion-corrosion repairs using coatings

    SciTech Connect

    Lichtenstein, J.

    2000-02-01

    Condenser corrosion and erosion problems involving condenser (heat exchanger) water boxes, tubesheets, and tubes have been a maintenance problem for many years and continue to be so. Most often the materials of construction for surface condensers are galvanically incompatible. Usually the water box is carbon steel (CS) or cast iron, the tubesheet can be either CS or a copper-based alloy, and the tubes frequently are either a copper-based alloy, stainless steel (SS), or titanium. When erosion-corrosion problems arise and upgrading the tube alloy is not feasible or does not correct the problem there is a relatively inexpensive method of preventing or reducing the damage--thereby prolonging the life of the tube. Operators can coat the inlet end in the attacked region (normally 6 to 10 in. inside the tube) and the tubesheet. The coating material usually is a 100% solid epoxy or other high-solids, high-quality organic material.

  19. Acoustic emission characterization of the onset of corrosion in reinforced concrete

    NASA Astrophysics Data System (ADS)

    Di Benedetti, M.; De Cais, E.; Karim, Z.; Loreto, G.; Presuel, F.; Nanni, A.

    2012-04-01

    The development of techniques capable of evaluating deterioration of reinforced concrete (RC) is instrumental to the advancement of the structural health monitoring (SHM) and service life estimate for constructed facilities. One of the main causes leading to degradation of RC is the corrosion of the steel reinforcement. This process can be modeled phenomenologically, while laboratory tests aimed at studying durability responses are typically accelerated in order to provide useful results within a realistic period of time. Among nondestructive methods, acoustic emission (AE) is emerging as a tool to detect the onset and progression of deterioration mechanisms. In this paper, the development of accelerated corrosion and continuous AE monitoring test set-up for RC specimens are presented. Relevant information are provided with regard to the characteristics of the corrosion circuit, continuous measurement and acquisition of corrosion potential, selection of AE sensors and AE parameter setting. Results from small-scale pre-notched RC specimens aim to isolate the frequency spectrum where the corrosion first takes place. Waveform analysis critical in the definition of a prognosis model will extend the AE dataset for the onset of corrosion.

  20. Effect of macrophages on in vitro corrosion behavior of magnesium alloy.

    PubMed

    Zhang, Jian; Hiromoto, Sachiko; Yamazaki, Tomohiko; Niu, Jialin; Huang, Hua; Jia, Gaozhi; Li, Haiyan; Ding, Wenjiang; Yuan, Guangyin

    2016-10-01

    The influence of cells on the corrosion behavior of biomedical magnesium alloy is an important but less studied topic, which is helpful for understanding the inconsistent corrosion rates between in vitro and in vivo experiments. In this work, macrophages were directly cultured on Mg-2.1Nd-0.2Zn-0.5Zr (wt %, abbreviated as JDBM) alloy surface for 72 or 168 hours. Macrophages retained good viability and the generation of reactive oxygen species (ROS) was greatly promoted on the alloy. Weight loss, Mg(2+) concentration, and cross-section observation results demonstrated that macrophages accelerated the in vitro corrosion of JDBM. The coverage of cell body did not affect the local thickness of corrosion product layer. The corrosion product layer had a porous inner Mg(OH)2 layer and a dense outer layer mainly composed of O, P, Mg, and Ca. The uniform acceleration of JDBM corrosion was attributed to the omnidirection diffusion of ROS from macrophages. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2476-2487, 2016. PMID:27223576

  1. PM alloy 625M for high strength corrosion resistant applications

    SciTech Connect

    Rizzo, F.J.; Floreen, S.

    1997-06-01

    In applications where the combination of high strength and good corrosion resistance are required, there have been only a few alloys of choice. A new powder metallurgy alloy has been developed, PM 625M, a niobium modification of Alloy 625, as a material to fill this need. One area of particular interest is the nuclear power industry, where many problems have been encountered with bolts, springs, and guidepins. Mechanical properties and stress corrosion cracking data of PM 625M are presented in this paper.

  2. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  3. Accelerated degradation testing of a photovoltaic module

    NASA Astrophysics Data System (ADS)

    Charki, Abdérafi; Laronde, Rémi; Bigaud, David

    2013-01-01

    There are a great many photovoltaic (PV) modules installed around the world. Despite this, not enough is known about the reliability of these modules. Their electrical power output decreases with time mainly as a result of the effects of corrosion, encapsulation discoloration, and solder bond failure. The failure of a PV module is defined as the point where the electrical power degradation reaches a given threshold value. Accelerated life tests (ALTs) are commonly used to assess the reliability of a PV module. However, ALTs provide limited data on the failure of a module and these tests are expensive to carry out. One possible solution is to conduct accelerated degradation tests. The Wiener process in conjunction with the accelerated failure time model makes it possible to carry out numerous simulations and thus to determine the failure time distribution based on the aforementioned threshold value. By this means, the failure time distribution and the lifetime (mean and uncertainty) can be evaluated.

  4. Corrosion of stainless steel, 2. edition

    SciTech Connect

    Sedriks, A.J.

    1996-10-01

    The book describes corrosion characteristics in all the major and minor groups of stainless steels, namely, in austenitic, ferritic, martensitic, duplex, and precipitation hardenable steels. Several chapters are spent on those special forms of corrosion that are investigated in the great detail in stainless steels, namely, pitting corrosion, crevice corrosion, and stress corrosion cracking. The influences of thermal treatment (heat affected zone cases), composition, and microstructure on corrosion are given good coverage. Corrosive environments include high temperature oxidation, sulfidation as well as acids, alkalis, various different petroleum plant environments, and even human body fluids (stainless steels are commonly used prosthetic materials).

  5. Effect of debonded interfaces on corrosion of mild steel composites in supercritical CO2-saturated brines

    SciTech Connect

    John, Han; Carey, James W; Zhang, Jinsuo

    2010-10-07

    The geologic sequestration of CO{sub 2} is a proposed method to limit greenhouse gas emissions and has been the subject of many studies in the last decade. Wellbore systems achieve isolation of the storage reservoir through a combination of steel (generally carbon steel) and Portland cement. CO{sub 2} leakage along the steel-cement interface has the potential to accelerate corrosion. We conduct experiments to assess the corrosion risk at cement-steel interface under in situ wellbore conditions. Wellbore interfaces were simulated by assemblies constructed of J55 mild steel and Portland class G (Epoxy was used in this study to separate) cement and corrosion was investigated in supercritical CO{sub 2} saturated brines, (NaCl = 1 wt%) at T = 50 C, pCO{sub 2} = 1200 psi with interface gap size = 100 {micro}m and {infinity} (open surface). The experiments were carried out in a high-pressure, 1.8 L autoclave. The corrosion kinetics were measured employing electrochemical techniques including linear polarization resistance and electrochemical impedance spectroscopy techniques. The corrosion scales were analyzed using secondary electron microscopy, back scattering electron microscopy, energy dispersive spectroscopy and x-ray diffraction. Corrosion rates decreased as time with or without interface gap. In this case corrosion rates are controlled by scale protectivity through the interface gap. Scaled steel corrosion rates were two orders of magnitude less compared with fresh steel. The corrosion scale is pseudo crystalline at the open interface. Well-crystallized scale was observed at interface gap sizes 100 {micro}m. All corrosion scales were composed of iron carbonates.

  6. Corrosion Evaluation of INTEC Waste Storage Tank WM-182

    SciTech Connect

    W. J. Dirk; P. A. Anderson

    1999-11-01

    ). For purposes of waste storage, this is a negligible amount of metal loss. Localized corrosion such as cracking, pitting, preferential weld attack, or weld heat affected zone attack is not expected to be a materials problem in the tank.

  7. Acceleration during magnetic reconnection

    SciTech Connect

    Beresnyak, Andrey; Li, Hui

    2015-07-16

    The presentation begins with colorful depictions of solar x-ray flares and references to pulsar phenomena. Plasma reconnection is complex, could be x-point dominated or turbulent, field lines could break due to either resistivity or non-ideal effects, such as electron pressure anisotropy. Electron acceleration is sometimes observed, and sometimes not. One way to study this complex problem is to have many examples of the process (reconnection) and compare them; the other way is to simplify and come to something robust. Ideal MHD (E=0) turbulence driven by magnetic energy is assumed, and the first-order acceleration is sought. It is found that dissipation in big (length >100 ion skin depths) current sheets is universal and independent on microscopic resistivity and the mean imposed field; particles are regularly accelerated while experiencing curvature drift in flows driven by magnetic tension. One example of such flow is spontaneous reconnection. This explains hot electrons with a power-law tail in solar flares, as well as ultrashort time variability in some astrophysical sources.

  8. Atmospheric corrosion model and monitor for low cost solar arrays

    NASA Technical Reports Server (NTRS)

    Kaelble, D. H.; Mansfeld, F. B.; Jeanjaquet, S. L.; Kendig, M.

    1981-01-01

    An atmospheric corrosion model and corrosion monitoring system has been developed for low cost solar arrays (LSA). The corrosion model predicts that corrosion rate is the product of the surface condensation probability of water vapor and the diffusion controlled corrosion current. This corrosion model is verified by simultaneous monitoring of weather conditions and corrosion rates at the solar array test site at Mead, Nebraska.

  9. Acceleration modules in linear induction accelerators

    NASA Astrophysics Data System (ADS)

    Wang, Shao-Heng; Deng, Jian-Jun

    2014-05-01

    The Linear Induction Accelerator (LIA) is a unique type of accelerator that is capable of accelerating kilo-Ampere charged particle current to tens of MeV energy. The present development of LIA in MHz bursting mode and the successful application into a synchrotron have broadened LIA's usage scope. Although the transformer model is widely used to explain the acceleration mechanism of LIAs, it is not appropriate to consider the induction electric field as the field which accelerates charged particles for many modern LIAs. We have examined the transition of the magnetic cores' functions during the LIA acceleration modules' evolution, distinguished transformer type and transmission line type LIA acceleration modules, and re-considered several related issues based on transmission line type LIA acceleration module. This clarified understanding should help in the further development and design of LIA acceleration modules.

  10. Corrosion detection in multi-layered rotocraft structures

    SciTech Connect

    ROACH,DENNIS P.; WALKINGTON,PHILLIP D.; HOHMAN,ED; MARSHALL,GREG

    2000-04-25

    Rotorcraft structures do not readily lend themselves to quantifiable inspection methods due to airframe construction techniques. Periodic visual inspections are a common practice for detecting corrosion. Unfortunately, when the telltale signs of corrosion appear visually, extensive repair or refurbishment is required. There is a need to nondestructively evaluate airframe structures in order to recognize and quantify corrosion before visual indications are present. Nondestructive evaluations of rotorcraft airframes face inherent problems different from those of the fixed wing industry. Most rotorcraft lap joints are very narrow, contain raised fastener heads, may possess distortion, and consist of thinner gage materials ({approximately}0.012--0.125 inches). In addition the structures involve stack-ups of two and three layers of thin gage skins that are separated by sealant of varying thickness. Industry lacks the necessary data techniques, and experience to adequately perform routine corrosion inspection of rotorcraft. In order to address these problems, a program is currently underway to validate the use of eddy current inspection on specific rotorcraft lap joints. Probability of detection (POD) specimens have been produced that simulate two lap joint configurations on a model TH-57/206 helicopter. The FAA's Airworthiness Assurance Center (AANC) at Sandia Labs and Bell Helicopter have applied single and dual frequency eddy current (EC) techniques to these test specimens. The test results showed enough promise to justify beta site testing of the eddy current methods evolved in this study. The technique allows users to distinguish between corrosion signals and those caused by varying gaps between the assembly of skins. Specific structural joints were defined as prime corrosion areas and a series of corrosion specimens were produced with 5--20% corrosion distributed among the layers of each joint. Complete helicopter test beds were used to validate the laboratory

  11. Corrosion-resistant coating development

    SciTech Connect

    Stinton, D.P.; Kupp, D.M.; Martin, R.L.

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  12. Corrosion and corrosion fatigue of airframe aluminum alloys

    NASA Technical Reports Server (NTRS)

    Chen, G. S.; Gao, M.; Harlow, D. G.; Wei, R. P.

    1994-01-01

    Localized corrosion and corrosion fatigue crack nucleation and growth are recognized as degradation mechanisms that effect the durability and integrity of commercial transport aircraft. Mechanically based understanding is needed to aid the development of effective methodologies for assessing durability and integrity of airframe components. As a part of the methodology development, experiments on pitting corrosion, and on corrosion fatigue crack nucleation and early growth from these pits were conducted. Pitting was found to be associated with constituent particles in the alloys and pit growth often involved coalescence of individual particle-nucleated pits, both laterally and in depth. Fatigue cracks typically nucleated from one of the larger pits that formed by a cluster of particles. The size of pit at which fatigue crack nucleates is a function of stress level and fatigue loading frequency. The experimental results are summarized, and their implications on service performance and life prediction are discussed.

  13. Searching for corrosion intelligence

    SciTech Connect

    Roberge, P.R.

    1999-11-01

    The incredible progress in computing power and availability has created a tremendous wealth of information available at the touch of a few buttons. However, such wealth can easily provoke what is commonly described as `information overload.` The massive number of connections produced by a single search of the Web, for example, can greatly overwhelm users of this new technology. The rapidity of Web searches is due to the synergy between progress made in network connectivity protocols, intelligent search strategies and supporting hardware. This paper will attempt to define the basic elements of machine intelligence in the context of corrosion engineering and examine what has been done or could be done to introduce artificial thinking into daily operations.

  14. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1995-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  15. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, T.D.

    1996-07-23

    Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

  16. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  17. Durability Tests of a Fiber Optic Corrosion Sensor

    PubMed Central

    Wan, Kai Tai; Leung, Christopher K.Y.

    2012-01-01

    Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR) and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively. PMID:22737030

  18. Stress corrosion cracking evaluation of martensitic precipitation hardening stainless steels

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The resistance of the martensitic precipitation hardening stainless steels PH13-8Mo, 15-5PH, and 17-4PH to stress corrosion cracking was investigated. Round tensile and c-ring type specimens taken from several heats of the three alloys were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, to salt spray, and to a seacoast environment. The results indicate that 15-5PH is highly resistant to stress corrosion cracking in conditions H1000 and H1050 and is moderately resistant in condition H900. The stress corrosion cracking resistance of PH13-8Mo and 17-4PH stainless steels in conditions H1000 and H1050 was sensitive to mill heats and ranged from low to high among the several heats included in the tests. Based on a comparison with data from seacoast environmental tests, it is apparent that alternate immersion in 3.5 percent salt water is not a suitable medium for accelerated stress corrosion testing of these pH stainless steels.

  19. Environmentally Friendly Corrosion Preventative Compounds for Ground Support Structures

    NASA Technical Reports Server (NTRS)

    Montgomery Eliza L.; Calle, Luz, Marina; Curran, Jerome P.; Kolody, Mark R.

    2013-01-01

    The need to use environmentally friendly technologies throughout future space-related launch programs prompted a study aimed at replacing current petroleum and solvent-based Corrosion Preventive Compounds (CPCs) with environmentally friendly alternatives. The work in this paper focused on the identification and evaluation of environmentally friendly CPCs for use in protecting flight hardware and ground support equipment from atmospheric corrosion. CPCs are used as temporary protective coatings and must survive in the aggressive coastal marine environment that exists throughout the Kennedy Space Center, Florida. The different protection behaviors of fifteen different oily film CPCs, both common petroleum-based and newer environmentally friendly types, were evaluated on various steel and aluminum substrates. CPC and substrate systems were subjected to atmospheric testing at the Kennedy Space Center's Beachside Atmospheric Corrosion Test Site, as well as cyclic accelerated corrosion testing. Each CPC also underwent physical characterization and launch-related compatibility testing. The results for the fifteen CPC systems are presented in this paper.

  20. Environmentally friendly corrosion preventive compounds for ground support structures

    NASA Astrophysics Data System (ADS)

    Montgomery, Eliza; Curran, Jerome; Calle, Luz Marina; Kolody, Mark

    The need to use environmentally friendly technologies throughout future space-related launch programs prompted a study aimed at replacing current petroleum and solvent-based corrosion preventive compounds (CPCs) with environmentally friendly alternatives. The work in this paper focused on the identification and evaluation of environmentally friendly CPCs for use in protecting flight hardware and ground support equipment from atmospheric corrosion. CPCs are used as temporary protective coatings and must survive in the aggressive coastal marine environment that exists throughout the Kennedy Space Center, Florida. The different protection behaviors of fifteen different oily film CPCs, both common petroleum-based and newer environmentally friendly types, were evaluated on various steel and aluminum substrates. CPC and substrate systems were subjected to atmospheric testing at the Kennedy Space Center's Beachside Atmospheric Corrosion Test Site, as well as cyclic accelerated corrosion testing. Each CPC also underwent physical characterization and launch-related compatibility testing. The results for the fifteen CPC systems are presented in this paper.

  1. Durability tests of a fiber optic corrosion sensor.

    PubMed

    Wan, Kai Tai; Leung, Christopher K Y

    2012-01-01

    Steel corrosion is a major cause of degradation in reinforced concrete structures, and there is a need to develop cost-effective methods to detect the initiation of corrosion in such structures. This paper presents a low cost, easy to use fiber optic corrosion sensor for practical application. Thin iron film is deposited on the end surface of a cleaved optical fiber by sputtering. When light is sent into the fiber, most of it is reflected by the coating. If the surrounding environment is corrosive, the film is corroded and the intensity of the reflected signal drops significantly. In previous work, the sensing principle was verified by various experiments in laboratory and a packaging method was introduced. In this paper, the method of multiplexing several sensors by optical time domain reflectometer (OTDR) and optical splitter is introduced, together with the interpretation of OTDR results. The practical applicability of the proposed sensors is demonstrated in a three-year field trial with the sensors installed in an aggressive marine environment. The durability of the sensor against chemical degradation and physical degradation is also verified by accelerated life test and freeze-thaw cycling test, respectively. PMID:22737030

  2. Prevention of corrosion-related failures in condensers and feedwater heaters

    SciTech Connect

    Beavers, J.A.; Agrawal, A.K.; Berry, W.E.

    1982-12-01

    The common alloys used for tubing in power plant feedwater heaters and condensers are identified and the major corrosion problems encountered in these components are described. The frequency of failure and failure modes in both components are shown to be alloy specific. Some corrosion problems are shown to be controllable through minor design modifications in the equipment and others through judicious selection of alloys. In condensers, alloy selection is most effective when based on tube location. In feedwater heaters, strict control of water quality is shown to be necessary with most alloys to minimize corrosion problems. Benefits of some auxiliary techniques for preventing corrosion attack include coating and cathodic protection of the tube sheet and cooling water intake screens.

  3. Corrosion of metal particle and metal evaporated tapes

    NASA Technical Reports Server (NTRS)

    Speliotis, Dennis E.

    1991-01-01

    Very high coercivity metal particle (MP) and metal evaporated (ME) tapes are being used in 8mm video and digital audio tape applications, and more recently in digital data recording applications. In view of the inherent susceptibility of such media to environmental corrosion, a number of recent studies have addressed their long term stability and archivability. These studies have used an accelerated corrosion test based either on elevated temperature-humidity or polluting gas atmospheres known as Battelle tests. A comparison of the Battelle test results performed at different laboratories reveals a large variation from one location to another, presumably due to incorrect replication of the Battelle condition. Furthermore, when the Battelle tests are performed on enclosed cartridges, it is quite possible that diffusion limits the penetration of the extremely low concentration polluting gaseous species to the inner layers of the tapes during the short time of the accelerated test, whereas in real life these diffusion limitations may not apply. To avoid this uncertainty, the corrosion behavior of commercial 8mm MP and ME tapes when cassettes without their external plastic cases were exposed to 50 deg C and 80 percent RH for 7.5 weeks is investigated.

  4. HIGH-TEMPEPATURE OXIDATION AND CORROSION OF MATERIALS PROGRAM

    SciTech Connect

    Whittle, D.P.

    1980-03-01

    The objective of this program is to gain an understanding of the corrosion chemistry and materials behavior in high temperature environments. Of particular interest are the mechanisms of attack in environments containing more than one reactive species, for example sulfur and oxygen. Sulfur is a critical impurity in almost all energy sources and leads to accelerated, and often unacceptable rates of metal degradation. In addition, the competitive formation of potentially more than one phase as a reaction product is an important fundamental problem, and can only be truly understood if the underlying thermodynamic and transport properties of the systems, and their interrelation, are identified. Sulfur can appear in a number of forms. In entirely gaseous environments it can appear as H{sub Z}S when the oxidizing potential of the atmosphere is low, such as might exist in energy conversion systems, or as SO{sub 2}/SO{sub 3} at higher oxygen potentials, such as those produced by fuel combustion. It may also appear in sulfatic deposits, either as a solid, such as CaSO{sub 4} in fluidized bed combustion systems, as inorganic and organic sulfur compounds in coal char, or as a liquid alkali-metal sulfate in coal-ash, or turbine-blade deposits. This last year has been spent primarily in establishing the typical behavioral patterns of common materials in these types of environments, and identifying the common mechanisms. In addition, development of definitive models of alloy reactions with single oxidants has continued. The individual projects are described.

  5. Engineering considerations for corrosion monitoring of gas gathering pipeline systems

    SciTech Connect

    Braga, T.G.; Asperger, R.G.

    1987-01-01

    Proper corrosion monitoring of gas gathering pipelines requires a system review to determine the appropriate monitor locations and types of monitoring techniques. This paper develops and discusses a classification of conditions such as flow regime and gas composition. Also discussed are junction categories which, for corrosion monitoring, need to be considered from two points of view. The first is related to fluid flow in the line and the second is related corrosion inhibitor movement along the pipeline. The appropriate application of the various monitoring techniques such as coupons, hydrogen detectors, electrical resistance probe and linear polarization probes are discussed in relation to flow regime and gas composition. Problems caused by semi-conduction from iron sulfide are considered. Advantages and disadvantages of fluid gathering methods such as pots and flow-through drips are discussed in relation to their reliability as on-line monitoring locations.

  6. Mullite coatings for corrosion protection of silicon carbide

    SciTech Connect

    Mulpuri, R.; Sarin, V.K.

    1995-08-01

    SiC based ceramics have been identified as the leading candidate materials for elevated temperature applications in harsh oxidation/corrosion environments. It has been established that a protective coating can be effectively used to avoid problems with excessive oxidation and hot corrosion. However, to date, no coating configuration has been developed that can satisfy the stringent requirements imposed by such applications. Chemical Vapor Deposited (CVD) mullite coatings due to their desirable properties of toughness, corrosion resistance, and a good coefficient of thermal expansion match with SiC are being investigated as a potential candidate. Since mullite has never been successfully grown via CVD, the thermodynamics and kinetics of its formation were initially established and used as a guideline in determining the initial process conditions. Process optimization was carried out using an iterative process of theoretical analysis and experimental work coupled with characterization and testing. The results of theoretical analysis and the CVD formation characteristics of mullite are presented.

  7. Microbiologically influenced corrosion of steel during putrefaction of seawater: Evidence for a new mechanism

    SciTech Connect

    Eashwar, M. ); Chandrasekaran, P.; Subramanian, G. ); Balakrishnan, K. )

    1993-02-01

    The influence of putrid seawater on the performance of mild steel has been investigated in laboratory tests with decomposing Ulva lactuca. During a 30-day period, the corrosion of steel was considerably enhanced by increased rates of putrefaction. However, accelerated rates of corrosion in the presence of large amounts of decomposing organisms were limited to the initial stages prior to oxygen depletion and rapid sulfide production. Evidence for microbiological oxidation of sulfur in algal proteins is presented, and this process appears to have a significant effect on pH. Acidification of seawater by thiobacilli and the coexistence of oxygen and sulfide are two important phenomena involved in corrosion enhancement contrary to the prevalent thought emphasizing anaerobic corrosion. Implications of the present findings to natural systems are considered.

  8. Susceptibility of Aluminum Alloys to Corrosion in Simulated Fuel Blends Containing Ethanol

    SciTech Connect

    Thomson, Jeffery K; Pawel, Steven J; Wilson, Dane F

    2013-01-01

    The compatibility of aluminum and aluminum alloys with synthetic fuel blends comprised of ethanol and reference fuel C (a 50/50 mix of toluene and iso-octane) was examined as a function of water content and temperature. Commercially pure wrought aluminum and several cast aluminum alloys were observed to be similarly susceptible to substantial corrosion in dry (< 50 ppm water) ethanol. Corrosion rates of all the aluminum materials examined was accelerated by increased temperature and ethanol content in the fuel mixture, but inhibited by increased water content. Pretreatments designed to stabilize passive films on aluminum increased the incubation time for onset of corrosion, suggesting film stability is a significant factor in the mechanism of corrosion.

  9. Note: Inhibiting bottleneck corrosion in electrical calcium tests for ultra-barrier measurements

    NASA Astrophysics Data System (ADS)

    Nehm, F.; Müller-Meskamp, L.; Klumbies, H.; Leo, K.

    2015-12-01

    A major failure mechanism is identified in electrical calcium corrosion tests for quality assessment of high-end application moisture barriers. Accelerated calcium corrosion is found at the calcium/electrode junction, leading to an electrical bottleneck. This causes test failure not related to overall calcium loss. The likely cause is a difference in electrochemical potential between the aluminum electrodes and the calcium sensor, resulting in a corrosion element. As a solution, a thin, full-area copper layer is introduced below the calcium, shifting the corrosion element to the calcium/copper junction and inhibiting bottleneck degradation. Using the copper layer improves the level of sensitivity for the water vapor transmission rate (WVTR) by over one order of magnitude. Thin-film encapsulated samples with 20 nm of atomic layer deposited alumina barriers this way exhibit WVTRs of 6 × 10-5 g(H2O)/m2/d at 38 °C, 90% relative humidity.

  10. Steam assisted oxide growth on aluminium alloys using oxidative chemistries: Part II corrosion performance

    NASA Astrophysics Data System (ADS)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    2015-11-01

    Surface treatment of aluminium alloys using steam with oxidative chemistries, namely KMnO4 and HNO3 resulted in accelerated growth of oxide on aluminium alloys. Detailed investigation of the corrosion performance of the treated surfaces was carried out using potentiodynamic polarisation and standard industrial test methods such as acetic acid salt spray (AASS) and filiform corrosion on commercial AA6060 alloy. Barrier properties of the film including adhesion were evaluated using tape test under wet and dry conditions. Electrochemical results showed reduced cathodic and anodic activity, while the protection provided by steam treatment with HNO3 was a function of the concentration of NO3- ions. The coating generated by inclusion of KMnO4 showed highest resistance to filiform corrosion. Overall, the performance of the steam treated surfaces under filiform corrosion and AASS test was a result of the local coverage of the alloy microstructure resulting from steam containing with KMnO4 and HNO3.

  11. Stress Corrosion Cracking of Basalt/Epoxy Composites under Bending Loading

    NASA Astrophysics Data System (ADS)

    Shokrieh, Mahmood M.; Memar, Mahdi

    2010-04-01

    The purpose of this research is to study the stress corrosion behavior of basalt/epoxy composites under bending loading and submerged in 5% sulfuric acid corrosive medium. There are limited numbers of research in durability of fiber reinforced polymer composites. Moreover, studies on basalt fibers and its composites are very limited. In this research, mechanical property degradation of basalt/epoxy composites under bending loading and submerged in acidic corrosive medium is investigated. Three states of stress, equal to 30%, 50% and 70% of the ultimate strength of composites, are applied on samples. High stress states are applied to the samples to accelerate the testing procedure. Mechanical properties degradation consists of bending strength, bending modulus of elasticity and fracture energy of samples are examined. Also, a normalized strength degradation model for stress corrosion condition is presented. Finally, microscopic images of broken cross sections of samples are examined.

  12. Review on stress corrosion and corrosion fatigue failure of centrifugal compressor impeller

    NASA Astrophysics Data System (ADS)

    Sun, Jiao; Chen, Songying; Qu, Yanpeng; Li, Jianfeng

    2015-03-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  13. Localized corrosion of high performance metal alloys in an acid/salt environment

    NASA Technical Reports Server (NTRS)

    Macdowell, L. G.; Ontiveros, C.

    1991-01-01

    Various vacuum jacketed cryogenic supply lines at the Space Shuttle launch site at Kennedy Space Center use convoluted flexible expansion joints. The atmosphere at the launch site has a very high salt content, and during a launch, fuel combustion products include hydrochloric acid. This extremely corrosive environment has caused pitting corrosion failure in the thin walled 304L stainless steel flex hoses. A search was done to find a more corrosion resistant replacement material. The study focussed on 19 metal alloys. Tests which were performed include electrochemical corrosion testing, accelerated corrosion testing in a salt fog chamber, and long term exposure at a beach corrosion testing site. Based on the results of these tests, several nickel based alloys were found to have very high resistance to this corrosive environment. Also, there was excellent agreement between the electrochemical tests and the actual beach exposure tests. This suggests that electrochemical testing may be useful for narrowing the field of potential candidate alloys before subjecting samples to long term beach exposure.

  14. Monitoring of corrosion damage using high-frequency guided ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Chew, D.; Fromme, P.

    2014-03-01

    Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

  15. Monitoring of corrosion damage using high-frequency guided ultrasonic waves

    NASA Astrophysics Data System (ADS)

    Chew, D.; Fromme, P.

    2015-03-01

    Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

  16. Corrosion Assessment of Candidate Materials for the SHINE Subcritical Assembly Vessel and Components FY15 Report

    SciTech Connect

    Pawel, Steven J.

    2016-01-01

    In the previous report of this series, a literature review was performed to assess the potential for substantial corrosion issues associated with the proposed SHINE process conditions to produce 99Mo. Following the initial review, substantial laboratory corrosion testing was performed emphasizing immersion and vapor-phase exposure of candidate alloys in a wide variety of solution chemistries and temperatures representative of potential exposure conditions. Stress corrosion cracking was not identified in any of the exposures up to 10 days at 80°C and 10 additional days at 93°C. Mechanical properties and specimen fracture face features resulting from slow-strain rate tests further supported a lack of sensitivity of these alloys to stress corrosion cracking. Fluid velocity was found not to be an important variable (0 to ~3 m/s) in the corrosion of candidate alloys at room temperature and 50°C. Uranium in solution was not found to adversely influence potential erosion-corrosion. Potentially intense radiolysis conditions slightly accelerated the general corrosion of candidate alloys, but no materials were observed to exhibit an annualized rate above 10 μm/y.

  17. Accelerated Aging of Polymer Composite Bridge Materials

    SciTech Connect

    J. G. Rodriguez; L. G. Blackwood; L. L. Torres; N. M. Carlson; T. S. Yoder

    1999-03-01

    Accelerated aging research on samples of composite material and candidate ultraviolet (UV) protective coatings is determining the effects of six environmental factors on material durability. Candidate fastener materials are being evaluated to determine corrosion rates and crevice corrosion effects at load-bearing joints. This work supports field testing of a 30-ft long, 18-ft wide polymer matrix composite (PMC) bridge at the Idaho National Engineering and Environmental Laboratory (INEEL). Durability results and sensor data from tests with live loads provide information required for determining the cost/benefit measures to use in life-cycle planning, determining a maintenance strategy, establishing applicable inspection techniques, and establishing guidelines, standards, and acceptance criteria for PMC bridges for use in the transportation infrastructure.

  18. Tank 241-AY-102 Secondary Liner Corrosion Evaluation - 14191

    SciTech Connect

    Boomer, Kayle D.; Washenfelder, Dennis J.; Johnson, Jeremy M.

    2014-01-07

    In October 2012, Washington River Protection Solutions, LLC (WRPS) determined that the primary tank of 241-AY-102 (AY-102) was leaking. A number of evaluations were performed after discovery of the leak which identified corrosion from storage of waste at the high waste temperatures as one of the major contributing factors in the failure of the tank. The propensity for corrosion of the waste on the annulus floor will be investigated to determine if it is corrosive and must be promptly removed or if it is benign and may remain in the annulus. The chemical composition of waste, the temperature and the character of the steel are important factors in assessing the propensity for corrosion. Unfortunately, the temperatures of the wastes in contact with the secondary steel liner are not known; they are estimated to range from 45 deg C to 60 deg C. It is also notable that most corrosion tests have been carried out with un-welded, stress-relieved steels, but the secondary liner in tank AY-102 was not stress-relieved. In addition, the cold weather fabrication and welding led to many problems, which required repeated softening of the metal to flatten secondary bottom during its construction. This flame treatment may have altered the microstructure of the steel.

  19. Corrosion and arc erosion in MHD channels. Final report

    SciTech Connect

    Rosa, R.J.; Pollina, R.J. |

    1992-08-01

    The problems connected with gas side corrosion for the design of the lA4 (POC) channel hardware are explored and results of gas side wear rate tests in the Textron Mark VII facility are presented. It is shown that the proposed designs meet a 2000 hour lifetime criterion based upon these materials tests. Improvement in cathode lifetime is demonstrated with lower voltage intercathode gaps. The corrosion of these materials is discussed and it is shown how lifetimes are dependent upon gap voltage and average metal temperature. The importance of uniformity of slagging to the durability of the anode wall is demonstrated. The wear mechanism of the anodes in the MHD channel is analyzed. In addition to gas-side corrosion, the results of specific water corrosion tests of sidewall materials are discussed. All of the tests reported here were carried out to confirm the gas-side performance and the manufacturability of anode and sidewall designs and to address questions posed about the durability of tungsten-copper on the waterside. the results of water corrosion tests of the tungsten copper alloy sidewall material are presented to show that with proper control of waterside pH and, if necessary, dissolved oxygen, one can obtain reliable performance with no degradation of heat transfer with this material. The final choice of materials was determined primarily by the outcome of these tests and also by the question of the manufacturability of the prospective designs.

  20. Corrosion fatigue crack growth behavior of titanium alloys in aqueous solutions

    SciTech Connect

    Shipilov, S.A.

    1998-01-01

    The corrosion fatigue crack growth (FCG) behavior, the effect of applied potential on corrosion FCG rates, and the fracture surfaces of VT20 (near-{alpha}) and TS6 (near-{beta}) titanium alloys were studied. Environments were aqueous solutions of sodium chloride (NaCl), sodium hydroxide (NaOH), potassium hydroxide (KOH), ferric chloride (FeCl{sub 3}), and chromic acid (H{sub 2}CrO{sub 4}) with and without NaCl. Depending upon solution composition, corrosion FCG rates were found to be higher or lower than those in air. Cathodic polarization retarded the corrosion FCG, while anodic polarization accelerated insignificantly or almost did not influence it in most of the solutions investigated. However, cathodic polarization accelerated corrosion FCG in 0.6 M FeCl{sub 3} and 0.5 M to 2 M H{sub 2}CrO{sub 4} + 0.01 M to 0.1 M NaCl solutions by a dozen times when the maximum stress intensity (K{sub max}) exceeded certain critical values. When K{sub max} was lower than the critical values, the same cathodic polarization (with all other /conditions being equal) retarded corrosion FCG. Results suggested the accelerated crack growth at cathodic potentials resulted from hydrogen-induced cracking (HIC). Therefore, critical values of K{sub max}, as well as the stress intensity range ({Delta}K) were regarded as corresponding to the beginning of corrosion FCG according to a HIC mechanism and designated as K{sub HIC} and {Delta}K{sub HIC}.