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Sample records for localized corrosion iii

  1. 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]).

  2. Tubercles and Localized Corrosion on Carbon Steel

    DTIC Science & Technology

    2011-02-16

    with symbiotic relationships and nutrient cycling. Miller and Tiller [14] indicated, "iron bacteria , which, together with the ferric hydroxide they...be used to conclude localized corrosion directly under the tubercles or a role for bacteria in their formation. 15. SUBJECT TERMS tubercle...corrosion, iron-oxidizing bacteria , magnetite 16. SECURITY CLASSIFICATION OF: a. REPORT Unclassified b. ABSTRACT Unclassified c. THIS PAGE

  3. General Corrosion and Localized Corrosion of the Drip Shield

    SciTech Connect

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material 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]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  4. General Corrosion and Localized Corrosion of Waste Package Outer Barrier

    SciTech Connect

    Farmer, J.C.; McCright, R.D.

    2000-01-28

    Alloy 22 is an extremely Corrosion Resistant Material, with a very stable passive film. Based upon exposures in the LTCTF, the GC rates of Alloy 22 are typically below the level of detection, with four outliers having reported rates up to 0.75 #mu#m per year. In any event, over the 10,000 year life of the repository, GC of the Alloy 22 (assumed to be 2 cm thick) should not be life limiting. Because measured corrosion potentials are far below threshold potentials, localized breakdown of the passive film is unlikely under plausible conditions, even in SSW at 120 deg C. The pH in ambient-temperature crevices formed from Alloy 22 have been determined experimentally, with only modest lowering of the crevice pH observed under plausible conditions. Extreme lowering of the crevice pH was only observed under situations where the applied potential at the crevice mouth was sufficient to result in catastrophic breakdown of the passive film above the threshold potential in non-buffered conditions not characteristic of the Yucca Mountain environment. In cases where naturally ocurring buffers are present in the crevice solution, little or no lowering of the pH was observed, even with significant applied potential. With exposures of twelve months, no evidence of crevice corrosion has been observed in SDW, SCW and SAW at temperatures up to 90 deg C. An abstracted model has been presented, with parameters determined experimentally, that should enable performance assessment to account for the general and localized corrosion of this material. A feature of this model is the use of the materials specification to limit the range of corrosion and threshold potentials, thereby making sure that substandard materials prone to localized attack are avoided. Model validation will be covered in part by a companion SMR on abstraction of this model.

  5. Localized corrosion in halides other than chlorides

    SciTech Connect

    Koch, G.H.

    1995-12-31

    This literature survey characterizes the effects of non-chloride halides on localized corrosion. It includes published material and unpublished data obtained through a questionnaire. Chapters cover Stainless Steels, Nickel, Titanium, and Zirconium. The engineer can use this information for material selection.

  6. Tubercles and Localized Corrosion on Carbon Steel

    DTIC Science & Technology

    2010-12-01

    with symbiotic relationships and nutrient cycling. Miller and Tiller [14] indicated, "iron bacteria , which, together with the ferric hydroxide...conclude localized corrosion directly under the tubercles or a role for bacteria in their formation. 15. SUBJECT TERMS tubercle, carbon steel... bacteria in their formation. Introduction It is well established that tubercles formed on austenitic 300 series (304 or 316) stainless steel in

  7. Localized Corrosion of Alloy 22 -Fabrication Effects-

    SciTech Connect

    Rebak, R B

    2005-11-05

    This report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats of Alloy 22 for container fabrication. Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual repository environments in Yucca Mountain. For example, to determine the intergranular attack in the heat affected zone of a weldment, tests are conducted in boiling acidic and oxidizing solutions according to ASTM standards. These solutions are used to compare the behavior of differently treated metallic coupons. Similarly for electrochemical tests many times pure sodium chloride or calcium chloride solutions are used. Pure chloride solutions are not representative of the repository environment. (1) Surface Stress Mitigation: When metallic plates are welded, for example using the Gas Tungsten Arc Welding (GTAW) method, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to comparatively test the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results from both immersion and electrochemical corrosion tests show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied. (2) Behavior of Specimens from a Mockup container: Alloy 22 has been extensively tested for

  8. General Corrosion and Localized Corrosion of the Drip Shield

    SciTech Connect

    F. Hua; K. Mon

    2003-06-24

    The recommended waste package (WP) design is described in BSC (2001a). The design includes a double-wall WP underneath a protective drip shield (DS) (BSC 2003a). The purpose of the process-level models developed in this report is to model dry oxidation (DOX), general corrosion (GC) and localized corrosion (LC) of the DS plate material, which is made of Ti Grade 7. The DS design also includes structural supports fabricated from Ti Grade 24. Degradation of Ti Grade 24 is not considered in this report. The DS provides protection for the waste package outer barrier (WPOB) both as a barrier to seepage water contact and a physical barrier to potential rockfall. This Model Report (MR) serves as a feed to the Integrated Waste Package Degradation Model (IWPD) analyses, and was developed in accordance with the Technical Work Plan (TWP) (BSC 2002a). The models contained in this report serve as a basis to determine whether or not the performance requirements for the DS can be met.

  9. Localized corrosion in materials for geothermal power

    SciTech Connect

    Roy, A.; Peterson, J.A.; Hehemann, R.F.; Troiano, A.R.

    1980-12-01

    Ten different commercially available steels were examined for general and localized corrosion in 14 different environmental conditions. The chloride concentration was varied from 1 to 24 percent. In general, the influence of chloride was minor and seemed slightly more agressive at 1 than at 5 or 24 percent. The brines were examined with and without saturated H/sub 2/S. Saturation with H/sub 2/S increased the general corrosion rate but appeared to reduce crevice attack in the acid solutions. Selected brines were examined in both acid and neutral conditions. As anticipated, a neutral brine with or without H/sub 2/S greatly reduced all forms of attack. Tests at 150/sup 0/C exhibited greater attack than at ambient. A relatively new alloy, Ni-Cu-Cb, consistently demonstrated good resistance to both general and localized attack. Typical economical N80 grade steels clearly demonstrated the strong dependence of localized attack on inclusion variables and offer great promise in the minimized and/or controlled inclusion condition. The Cr-Mo steels surprisingly did not look good at ambient but did exhibit substantial improvement at 150/sup 0/C. The laboratory tests gave higher weight loss values for similar steels recently tested in a well; although in neutral brines without saturated H/sub 2/S, the difference was not significantly larger.

  10. Studying localized corrosion using liquid cell transmission electron microscopy.

    PubMed

    Chee, See Wee; Pratt, Sarah H; Hattar, Khalid; Duquette, David; Ross, Frances M; Hull, Robert

    2015-01-04

    Localized corrosion of Cu and Al thin films exposed to aqueous NaCl solutions was studied using liquid cell transmission electron microscopy (LCTEM). We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au(+) ions, can modify the corrosion susceptibility of Al films.

  11. Localized weld metal corrosion in stainless steel water tanks

    SciTech Connect

    Strum, M.J.

    1995-05-25

    The rapidly developed leaks within the TFC and TFD tanks (LLNL groundwater treatment facilities) were caused by localized corrosion within the resolidified weld metal. The corrosion was initiated by the severe oxidation of the backsides of the welds which left the exposed surfaces in a condition highly susceptible to aqueous corrosion. The propagation of surface corrosion through the thickness of the welds occurred by localized corrosive attack. This localized attack was promoted by the presence of shielded aqueous environments provided by crevices at the root of the partial penetration welds. In addition to rapid corrosion of oxidized surfaces, calcium carbonate precipitation provided an additional source of physical shielding from the bulk tank environment. Qualification testing of alternate weld procedures showed that corrosion damage can be prevented in 304L stainless steel GTA welds by welding from both sides while preventing oxidation of the tank interior through the use of an inert backing gas such as argon. Corrosion resistance was also satisfactory in GMA welds in which oxidized surfaces were postweld cleaned by wire brushing and chemically passivated in nitric acid. Further improvements in corrosion resistance are expected from a Mo-containing grade of stainless steel such as type 316L, although test results were similar for type 304L sheet welded with type 308L filler metal and type 316L sheet welded with type 316L filler metal.

  12. Tomographic spectral imaging: analysis of localized corrosion.

    SciTech Connect

    Michael, Joseph Richard; Kotula, Paul Gabriel; Keenan, Michael Robert

    2005-02-01

    of Cu electroplated with various metals. Figure 1A shows the top view of the localized corrosion region prepared for FIB sectioning. The TSI region has been coated with Pt and a trench has been milled along the bottom edge of the region, exposing it to the electron beam as seen in Figure 1B. The TSI consisted of 25 sections and was approximately 6Gbytes. Figure 1C shows several of the components rendered in 3D: Green is Cu; blue is Pb; cyan represents one of the corrosion products that contains Cu, Zn, O, S, and C; and orange represents the other corrosion product with Zn, O, S and C. Figure 1 D shows all of the component spectral shapes from the analysis. There is severe pathological overlap of the spectra from Ni, Cu and Zn as well as Pb and S. in spite of this clean spectral shapes have been extracted from the TSI. This powerful TSI technique could be applied to other sectioning methods well.

  13. Studying localized corrosion using liquid cell transmission electron microscopy

    DOE PAGES

    Chee, See Wee; Pratt, Sarah H.; Hattar, Khalid; ...

    2014-11-07

    Using liquid cell transmission electron microscopy (LCTEM), localized corrosion of Cu and Al thin films immersed in aqueous NaCl solutions was studied. We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au+ ions, can modify the corrosion susceptibility of Al films. Likewise, a discussion on strategies to control the onset of pitting is also presented.

  14. Studying localized corrosion using liquid cell transmission electron microscopy

    SciTech Connect

    Chee, See Wee; Pratt, Sarah H.; Hattar, Khalid; Duquette, David; Ross, Frances M.; Hull, Robert

    2014-11-07

    Using liquid cell transmission electron microscopy (LCTEM), localized corrosion of Cu and Al thin films immersed in aqueous NaCl solutions was studied. We demonstrate that potentiostatic control can be used to initiate pitting and that local compositional changes, due to focused ion beam implantation of Au+ ions, can modify the corrosion susceptibility of Al films. Likewise, a discussion on strategies to control the onset of pitting is also presented.

  15. General and localized corrosion of the drip shield

    SciTech Connect

    Estill, J C; Farmer, J C; McCright; R D

    1999-08-20

    Ti Gr 7 is an extremely corrosion resistant material, with a very stable passive film. Based upon exposures in the LTCTF, it has been determined that the general corrosion and oxidation rates of Ti Gr 7 are essentially below the level of detection. In any event, over the 10,000 year life of the repository, general corrosion and oxidation should not be life limiting. The large separation between measured corrosion and threshold potentials indicate that localized breakdown of the passive film is unlikely under plausible conditions, even in SSW at 120 C. In the future, the pH and current in crevices formed from Ti Gr 7 should be determined experimentally. With exposures of two years, no significant evidence of crevice corrosion has been observed with Ti Gr 16 in SDW, SCW, and SAW at temperatures up to 9O C, though many of the samples have a beautiful green patina. An abstracted model has been presented, with parameters determined experimentally, that should enable performance assessment to account for the general and localized corrosion of this material. A feature of this model is the use of the materials specification to limit the range of corrosion and threshold potentials, thereby making sure that substandard materials prone to localized attack are avoided.

  16. Influence of overaging treatment on localized corrosion of Al 6056

    SciTech Connect

    Gullaumin, V.; Mankowski, G.

    2000-01-01

    The influence of T78 overaging treatment on the corrosion behavior of AL 6056 (UNS A96056) in 1 M sodium chloride (NaCl) solution was investigated. The overaged alloy presented the same localized corrosion mechanisms as Al 6056-T6. However, Al 6056-T78 coarse intermetallic Al-Mg-Si-containing particles were found to be more reactive than those in the Al 6056-T6 alloy and were nucleation sites for pits. Pitting and intergranular corrosion were dependent upon each other; intergranular corrosion nucleated on pit walls. A quantitative study showed that T78 overaging of Al 6056 offered a better resistance to intergranular corrosion compared to T6 peak-aging treatment. The overaged alloy will be able to replace the traditional Al 2024 because of the efficiency of this overaging treatment.

  17. Interactions of different types of localized corrosion in surgical implants.

    PubMed

    Mori, G; Dösinger, H

    2004-03-01

    Surgical implants often show different types of localized corrosion such as corrosion fatigue cracking, pitting and crevice corrosion on the same part. Interactions of these different corrosion phenomena were investigated. This was done by cyclic loading of electropolished tensile specimens at different constant and changing potentials. Material investigated was a surgical implant steel X2CrNiMo18-15-3 which was immersed in physiological NaCl solution. Pitting and repassivation potentials were determined. Samples with and without artificial cracks as well as masked specimens were tested. Incubation period for first damage, density and size of pits by coulometric and volumetric method were determined. The fracture surfaces were then investigated by SEM. Results show that not in all cases pitting corrosion was the cause for corrosion fatigue cracking. Also pitting is favoured by crack formation. Density of pits increases by a factor of 5 without any change to pitting potential. There are primary pits formed prior to crack initiation and secondary pits formed after crack initiation. At samples without crack there is almost no difference between the optically measured value of total pit volume and the coulometrically determined value. At samples with cracks coulometric volume of pits is much larger than optical one. This proves that there is a significant amount of crevice corrosion in the crack. The corrosion current density in the crack increases by two orders of magnitude when comparing it to electropolished surface of the sample. Results of laboratory experiments are confirmed by failure of a real implant.

  18. Spatial Relationships Between Bacteria and Localized Corrosion,

    DTIC Science & Technology

    1996-03-01

    of corrosion products on specimens with crevices. After 11 days, 50 ml of natural seawater was added to the abiotic electrolytes containing electrodes...De Mele, H. A. Videla, "Interacciones de Biopeliculas Bacterianas y Compuestos Inorganicos Sobre Aceros Protegidos Catodicamente," 5th Congreso Ibero

  19. Corrosion Inhibition of Stress Corrosion Cracking and Localized Corrosion of Turbo-Expander Materials

    NASA Astrophysics Data System (ADS)

    Bavarian, Behzad; Zhang, Jia; Reiner, Lisa

    Stress corrosion cracking of 7050 aluminum alloy in the turbo expander and steam/gas turbine industry can cause catastrophic failures, especially for turbo machinery systems performing in hostile, corrosive environments. Commercially available inhibitors were investigated for their effectiveness in reducing and controlling the corrosion susceptibility. Inhibitor effectiveness was confirmed with electrochemical corrosion techniques. Polarization resistance increased with concentration of corrosion inhibitor due to film formation and displacement of water molecules. Cyclic polarization behavior for samples in the 1.0% to 10.0% inhibitor concentration showed a shift in the passive film breakdown potential. The substantial increase in the passive range has positive consequences for neutralizing pitting and crevice corrosion cell chemistry. The strain to failure and tensile strength determined from slow strain rate studies for the aluminum alloy showed pronounced improvement resulting from the inhibitors ability to mitigate SCC. Additionally, the fractographic analysis showed a changed morphology with ductile overload as the primary failure mode instead of transgranular or intergranular cracking.

  20. Localized corrosion in materials for geothermal power. Final report

    SciTech Connect

    Troiano, A.R.; Hehemann, R.F.

    1982-04-01

    The influence of 16 different geothermally related environments on a number of potentially useful steels was examined for both general and localized corrosion and at ambient and 150/sup 0/C. Variation in chloride concentration of 1 to 20% generally demonstrated only minor aggressiveness in acidified solutions. In general, the presence of H/sub 2/S raised the corrosion rate. However, very low concentrations (10 ppM) indicated higher rates than in saturated brines. This is rationalized on the basis of the inability to develop a semi-protective film at the low H/sub 2/S concentration. The corrosion rate for the Cr-Mo steel was unexpectedly high at ambient, but improved substantially at 150/sup 0/C. The Ni-Cu-Nb steel consistently demonstrated excellent resistance in all environments, except the 10 ppM H/sub 2/S at ambient. At 150/sup 0/C there were no exceptions to its superior performance. Maximum pit depth studies, analyzed statistically, indicated that the Ni-Cu-Nb alloy was the most resistant to localized attack. A clean (low inclusions) Mn-C and a clean vacuum melted steel ranked well. A comparison of two almost identical Mn-C steels one clean and one dirty clearly indicated the deleterious influence of inclusions on the tendency for localized corrosion. The profiling of a protected section of a creviced or pitted sample helped to delineate the nebulous line of demarcation between general and localized corrosion in these low alloy steels.

  1. Corrosion Damage Functions

    SciTech Connect

    Jones, Russell H.

    2002-11-30

    Corrosion damage can lead to reduced operational lifetimes. Often this damage is not as obvious as general corrosion but takes the form of pits, intergranular corrosion, crevice corrosion and hydrogen absorption. These types of corrosion damage lead to stress corrosion cracking, hydrogen induced cracking and corrosion fatigue. A critical step in defining a corrosion damage function is determining the relationship between the corrosion damage, the resulting crack propagation mechanism and component lifetimes. The sequence of events is often some localized corrosion event such as pitting, transition of the pit to a planar crack, propagation of this short crack, transition of the short crack to long crack conditions and continued propagation through Stage I, II, and III of the long crack SCC regimes. A description of critical corrosion damage processes and examples of the transition to long crack SCC conditions will be discussed.

  2. Localized corrosion of steels in geothermal steam/brine mixtures

    SciTech Connect

    McCright, R.D.; Frey, W.F.; Tardiff, G.E.

    1980-05-29

    Coupons of eight different carbon and chrome-moly alloy steels were exposed to high temperature, high salinity wellhead brine flow at a geothermal well in the Salton Sea Geothermal Field for periods of up to six months. The corrosion rate and corrosion attack morphology of each coupon was determined. Exposure time was a test variable and ranged from one month to six months. Test results indicate that carbon steels generally suffer high corrosion rates and are susceptible to severe localized attack which shows a mesa-canyon pattern. Chrome-moly alloy steels corrode at much lower rates and show an attack pattern of small shallow pits. With time, these pits grow mostly in the lateral direction. These results suggest that chrome-moly alloy steels offer significant improvement over carbon steels and that the disk-shaped pits are not likely to lead to rapid perforation.

  3. DETERMINATION OF CORROSION INHIBITOR CRITERIA FOR TYPE III/IIIA TANKS DURING SALT DISSOLUTION OPERATIONS SUMMARY DOCUMENT

    SciTech Connect

    Mickalonis, J.; Wiersma, B.; Garcia-Diaz, B.

    2009-10-01

    testing, pitting occurred on all coupons independent of heat treatment, inhibitor concentration, temperature, surface preparation, or welding. (4) In slow strain rate testing, cracking occurred on samples tested in solutions containing up to the maximum inhibitor concentration. The primary conclusion derived from this experimental program is that A537 carbon steel exposed to high nitrate (> 5.5M) solutions at inhibitor levels below the current specifications (0.6M OH{sup -} and 1.1M OH{sup -} + NO{sub 2}{sup -}) are susceptible to localized corrosion in the form of pitting and stress corrosion cracking. Long-term storage (e.g., greater than 100 days) of dissolved salt solutions not meeting the current inhibitor specifications for high nitrate salt chemistries in Type III waste tanks shall be avoided. Short term storage (e.g., less than 100 days) at low temperatures (e.g., less than 50 C) in these tanks is permissible for waste removal purposes. The stress relief process reduces the risk of SCC in the Type III waste tanks. On the other hand, the current inhibitor specifications should be strictly followed for the Type I, II and IV waste chemistry to prevent initiation of localized corrosion mechanisms. These tanks were not stress relieved and are more susceptible to SCC.

  4. How Dangerous Can Localized Corrosion Be? An Experiment that Studies Its Effects.

    ERIC Educational Resources Information Center

    Celdran, R.; Gonzalo, P.

    1988-01-01

    Considers three common cases of localized corrosion of metals: pitting, crevice, and stress corrosion. Provides experimental methods for studying all three methods. Includes a discussion of expected results. (ML)

  5. How Dangerous Can Localized Corrosion Be? An Experiment that Studies Its Effects.

    ERIC Educational Resources Information Center

    Celdran, R.; Gonzalo, P.

    1988-01-01

    Considers three common cases of localized corrosion of metals: pitting, crevice, and stress corrosion. Provides experimental methods for studying all three methods. Includes a discussion of expected results. (ML)

  6. PROBABILITY BASED CORROSION CONTROL FOR LIQUID WASTE TANKS - PART III

    SciTech Connect

    Hoffman, E.; Edwards, T.

    2010-12-09

    The liquid waste chemistry control program is designed to reduce the pitting corrosion occurrence on tank walls. The chemistry control program has been implemented, in part, by applying engineering judgment safety factors to experimental data. However, the simple application of a general safety factor can result in use of excessive corrosion inhibiting agents. The required use of excess corrosion inhibitors can be costly for tank maintenance, waste processing, and in future tank closure. It is proposed that a probability-based approach can be used to quantify the risk associated with the chemistry control program. This approach can lead to the application of tank-specific chemistry control programs reducing overall costs associated with overly conservative use of inhibitor. Furthermore, when using nitrite as an inhibitor, the current chemistry control program is based on a linear model of increased aggressive species requiring increased protective species. This linear model was primarily supported by experimental data obtained from dilute solutions with nitrate concentrations less than 0.6 M, but is used to produce the current chemistry control program up to 1.0 M nitrate. Therefore, in the nitrate space between 0.6 and 1.0 M, the current control limit is based on assumptions that the linear model developed from data in the <0.6 M region is applicable in the 0.6-1.0 M region. Due to this assumption, further investigation of the nitrate region of 0.6 M to 1.0 M has potential for significant inhibitor reduction, while maintaining the same level of corrosion risk associated with the current chemistry control program. Ongoing studies have been conducted in FY07, FY08, FY09 and FY10 to evaluate the corrosion controls at the SRS tank farm and to assess the minimum nitrite concentrations to inhibit pitting in ASTM A537 carbon steel below 1.0 molar nitrate. The experimentation from FY08 suggested a non-linear model known as the mixture/amount model could be used to predict

  7. 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)

  8. 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)

  9. Cooperative spreading of localized corrosion on heterogeneous materials

    NASA Astrophysics Data System (ADS)

    Budiansky, Noah D.

    It is believed that critical thresholds associated with localized corrosion of metals are not only associated with rapid growth of single pits but may also be associated with rapid growth in the number of pit sites. It is hypothesized that the explosive increase in the number of pit sites, the formation of pit clusters, and spreading of pits across surfaces are caused by cooperative interactions. The goal is to determine whether changes in various physical characteristics affect the extent of cooperative interactions and the associated critical thresholds. Decreasing the lateral diffusion length of aggressive species relative to the inter-inclusion spacing was found to shift the onset of rapid increases in number of pit sites, the degree of clustering, and the conventionally measured pitting potential by mitigating cooperative interactions. It was found that rapid increases in the conventionally measured pitting potential occurred when the lateral diffusion length decreased below a characteristic inter-inclusion spacing on a series of Fe-Cr-Ni-Mo alloys with different sulfur contents to control the inclusion density. Critical threshold potentials (ECrit) were found to be unaffected above a critical threshold potential, but increased rapidly below the critical threshold potential due to the mitigation of cooperative interactions. Small amounts of Ti were added to one Fe-Ni-Cr-Mo alloys to preferentially form acid resistant TiS inclusions instead of more susceptible MnS inclusions to mitigate cooperative interactions and increase ECrit when exposed to solutions that simulated cooperative interactions. MnS bearing stainless steels were found to be damaged by the same exposures and a decrease in ECrit was observed. Cooperative interactions were further extended to intergranular corrosion (IGC) of sensitized stainless steel, which contain networks of susceptible initiation sites in the form of Cr depleted grain boundaries. Cooperative interactions were found to initiate

  10. Corrosion behavior of as-received and previously cast type III gold alloy.

    PubMed

    Ayad, Mohamed F; Ayad, Ghada M

    2010-04-01

    The rationale for using gold alloys is based largely upon their alleged ability to resist corrosion, but little information is available to determine the corrosion behavior of recast alloys. This study characterized the elemental composition of as-received and recast type III gold alloy and examined the in vitro corrosion behavior in two media using a potentiodynamic polarization technique. Seventy-eight disk-shaped specimens were prepared from a type III gold alloy under three casting protocols according to the proportion of as-received and recast gold alloy (n = 26). (1) Group as received (100% as-received metal), (2) group 50% to 50% (50% wt. new metal, 50% wt. once recast metal), and (3) group recast (100% once recast metal). The surface structures of 20 specimens from each group were examined under scanning electron microscopy, and their elemental compositions were determined using X-ray energy-dispersive spectroscopy. Further, the potentiodynamic cyclic polarization between -1000 and +1000 mV (SCE) were performed for six specimens from each casting protocol in 0.09% NaCl solution (n = 3) and Fusayama artificial saliva (n = 3) at 37 degrees C. Zero-current potential and corrosion current density were determined. The data were analyzed with 1-way ANOVA and the Ryan-Einot-Gabriel-Welsch multiple-range test t (alpha= 0.05). Elemental composition was significantly different among the casting groups (p < 0.001). The mean weight percentage values were 72.4 to 75.7% Au, 4.5 to 7.0% Pd, 10.7 to 11.1% Ag, 7.8 to 8.4% Cu, and 1.0 to 1.4% Zn. The mean values for Zero-current potential and corrosion current density for all casting protocols were not significant (p > 0.05); however, the difference between the electrolytes was significant (p < 0.001). Fusayama artificial saliva seemed to offer the most corrosive environment. Type III gold alloy in any casting protocol retained passivity under electrochemical conditions similar to the oral environment. Moreover, high

  11. The effect of alloy composition on the localized corrosion behavior of nickel-chromium-molybdenum alloys

    NASA Astrophysics Data System (ADS)

    Wong, Fariaty

    increasing the Mo content. Chromium affects the metastable pits during the repassivation process where higher Cr content produces faster repassivation rates. The last part of the study addressed the role of alloying additions on the repassivation behavior of Ni-Cr-Mo alloys. Alloys with similar Mo content but higher Cr or higher Ni contents exhibited higher repassivation potentials. Higher Mo-containing alloys were shown to be very corrosion resistant since they did not experience any localized corrosion after rigorous polarization tests given that enough Cr was present. The repassivation potential was determined by the surface overpotential and thermodynamic contribution. XPS analysis found evidence of Cr(III) oxide as the main passivating agent. Molybdenum species primarily Mo(VI) and Cr(III) hydroxide were detected on the crevice attack area and on layer of films that formed from transpassive dissolution of higher Cr or higher Mo-containing alloys.

  12. Localized corrosion of stainless steels in ammonium chloride solutions

    SciTech Connect

    Forsen, O.; Aromaa, J.; Tavi, M.; Virtanen, J.

    1997-05-01

    Ammonium chloride deposition is a well-known problem in oil refining. When these deposits form in a moist environment, they are corrosive to carbon steel. When unexpected corrosion problems are faced, the material is often changed to alloys like stainless steels (SS). Electrochemical measurements were used to study the corrosion resistance of SS in ammonium chloride environments with different chloride contents and at different temperatures.

  13. Alloying effect of copper concentration on the localized corrosion of aluminum alloy for heat exchanger tube

    NASA Astrophysics Data System (ADS)

    Hong, Min-Sung; Park, In-Jun; Kim, Jung-Gu

    2017-07-01

    This study examined the alloying effect of Cu content on the localized corrosion properties of Al alloy in synthetic acid rain containing 200 ppm of Cl- ion. In aluminum alloy tubes, a small amount of Cu is contained as the additive to improve the mechanical strength or as the impurity. The Cu-containing intermetallic compound, Al2Cu can cause galvanic corrosion because it has more noble potential than Al matrix. Therefore aluminum tube could be penetrated by localized corrosion attack. The results were obtained from electrochemical test, scanning electron microscopy, and time of flight secondary ion mass spectrometry (ToF-SIMS) mapping. Severe localized corrosion was occurred on the Al-0.03 wt% Cu alloy. The negative effect of Cu on the pitting corrosion was attributed to the presence of the Al2Cu precipitates.

  14. IMPACT OF WATER CHEMISTRY ON LOCALIZED CORROSION OF COPPER PITTING

    EPA Science Inventory

    This project will help identify what waters are problematic in causing the corrosion of copper pipes and improve understanding of how water distribution leads to corrosion. This project will also focus on the prevention of pinhole leaks and how to reverse them once they occur. ...

  15. Localized corrosion and stress corrosion cracking resistance of friction stir welded aluminum alloy 5454

    SciTech Connect

    Frankel, G.S.; Xia, Z.

    1999-02-01

    The susceptibility of welded and unwelded samples of Al 5454 (UNS A95454) in the -O and -H34 tempers to pitting corrosion and stress corrosion cracking (SCC) in chloride solutions was studied. Welded samples were fabricated using the relatively new friction stir welding (FSW) process as well as a standard gas-tungsten arc welding process for comparison. Pitting corrosion was assessed through potentiodynamic polarization experiments. U-bend and slow strain rate tests were used to determine SCC resistance. The FSW samples exhibited superior resistance to pitting corrosion compared to the base metal and arc-welded samples. U-bend tests indicated adequate SCC resistance for the FSW samples. However, the FSW samples exhibited discontinuities that probably were associated with remnant boundaries of the original plates. These defects resulted in intermittent increased susceptibility to pitting and, particularly for Al 5454-H34 samples, poor mechanical properties in general.

  16. Interfacial valence electron localization and the corrosion resistance of Al-SiC nanocomposite

    PubMed Central

    Mosleh-Shirazi, Sareh; Hua, Guomin; Akhlaghi, Farshad; Yan, Xianguo; Li, Dongyang

    2015-01-01

    Microstructural inhomogeneity generally deteriorates the corrosion resistance of materials due to the galvanic effect and interfacial issues. However, the situation may change for nanostructured materials. This article reports our studies on the corrosion behavior of SiC nanoparticle-reinforced Al6061 matrix composite. It was observed that the corrosion resistance of Al6061 increased when SiC nanoparticles were added. Overall electron work function (EWF) of the Al-SiC nanocomposite increased, along with an increase in the corrosion potential. The electron localization function of the Al-SiC nanocomposite was calculated and the results revealed that valence electrons were localized in the region of SiC-Al interface, resulting in an increase in the overall work function and thus building a higher barrier to hinder electrons in the nano-composite to participate in corrosion reactions. PMID:26667968

  17. Dynamic Sensing of Localized Corrosion at the Metal/Solution Interface

    PubMed Central

    Li, Wei; Yuan, Boyu; Wang, Chao; Li, Liang; Chen, Shenhao

    2012-01-01

    A Mach-Zehnder interferometer is employed to detect localized corrosion at the metal/solution interface in the potentiodynamic sweep of the iron electrode in solutions. During the electrochemical reactions, local variations of the electrolyte's refractive index, which correlate with the concentration of dissolved species, change the optical path length (OPL) of the object beam when the beam passes through the electrolyte. The distribution of the OPL difference was obtained to present the concentration change of the metal ions visually, which enable direct evidence of corrosion processes. The OPL difference distribution shows localized and general corrosion during the anodic dissolution of the iron electrode in solutions with and without chloride ions, respectively. This method provides an approach for dynamic detection of localized corrosion at the metal/solution interface. PMID:22666070

  18. The Effect of Applied Tensile Stress on Localized Corrosion in Sensitized AA5083

    DTIC Science & Technology

    2015-09-01

    100°C. The sensitized samples were subjected to elastic tensile loading using a 4-point bend rig while being exposed to a 0.6 molar saltwater solution ...TENSILE STRESS ON LOCALIZED CORROSION IN SENSITIZED AA5083 by Roy T. Johnston September 2015 Thesis Advisor: Sarath K. Menon Co...AND DATES COVERED Master’s thesis 4. TITLE AND SUBTITLE THE EFFECT OF APPLIED TENSILE STRESS ON LOCALIZED CORROSION IN SENSITIZED AA5083 5

  19. Influence of hydrogen-oxidizing bacteria on the corrosion of low carbon steel: Local electrochemical investigations.

    PubMed

    Moreira, Rebeca; Schütz, Marta K; Libert, Marie; Tribollet, Bernard; Vivier, Vincent

    2014-06-01

    Low carbon steel has been considered a suitable material for component of the multi-barrier system employed on the geological disposal of high-level radioactive waste (HLW). A non negligible amount of dihydrogen (H2) is expected to be produced over the years within the geological repository due to the anoxic corrosion of metallic materials and also to the water radiolysis. The influence of the activity of hydrogen-oxidizing bacteria (HOB) and iron-reducing bacteria (IRB) on carbon steel corrosion is considered in this study because of the high availability of energetic nutriments (H2, iron oxides and hydroxides) produced in anoxic disposal conditions. Local electrochemical techniques were used for investigating the activity of IRB as a promoter of local corrosion in the presence of H2 as electron donor. A local consumption of H2 by the bacteria has been evidenced and impedance measurements indicate the formation of a thick layer of corrosion products.

  20. In situ characterization of localized corrosion of stainless steel by scanning electrochemical microscope

    NASA Astrophysics Data System (ADS)

    Yin, Yuehua; Niu, Lin; Lu, Min; Guo, Weikuan; Chen, Shenhao

    2009-08-01

    Scanning electrochemical microscopy (SECM) area scan measurements have been performed to investigate the localized corrosion of type 304 stainless steel in neutral chloride solution. Variations in the Faradaic current measured at selected tip potential values can be related to changes in the local concentration and electrochemical activities of electroactive species involved in corrosion reactions occurring at the substrate as a function of immersion times of the substrate and polarized currents or potentials applied on the substrate. To further verify the results acquired from cyclic voltammetric experiments, SECM measurements were employed to in situ study the compositions and electrochemical activity distribution profile of the pitting corrosion products of stainless steel. It has been demonstrated that the combination of feedback current mode with generation-collection (G-C) mode of SECM is suitable to elucidate the possible reaction mechanisms and paths involved in the localize corrosion of stainless steel in neutral chloride solution.

  1. Studies of localized corrosion in welded aluminum alloys by the scanning reference electrode technique

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Nunes, A. C.

    1995-01-01

    Localized corrosion in welded samples of 2219-T87 Al alloy (2319 filler), 2090 Al-Li alloy (4043 and 2319 fillers), and 2195 Al-Li alloy (4043 and 2319 fillers) has been investigated using the relatively new scanning reference electrode technique. The weld beads are cathodic in all cases, leading to reduced anode/cathode ratios. A reduction in anode/cathode ratio leads to an increase in the corrosion rates of the welded metals, in agreement with results obtained in previous electrochemical and stress corrosion studies involving the overall corrosion rates of welded samples. The cathodic weld beads are bordered on both sides by strong anodic regions, with high propensity for corrosion.

  2. Localized effects of macrofouling species on electrochemical corrosion of high grade alloys

    SciTech Connect

    Hodgkiess, T.; Nevilie, A.

    1998-12-31

    Interactions between macrofouling and corrosion on some stainless steels, UNS N06625 and UNS R30006 have been studied in long-term tests conducted in natural seawater off the west coast of Scotland. After a 18-month exposure period, the specimens were heavily fouled primarily with barnacles and mussels and all the materials exhibited crevice corrosion although this was less extensive on the Ni-base alloy. Localized corrosion was observed under the base of live barnacles on UNS S31603 stainless steel. DC electrochemical anodic polarization tests undertaken after the 18-month exposure period, yielded unusually high currents in the range of potential between the free corrosion value and the breakdown potential. This observation was associated with the appearance, after the anodic polarization, of black sulfide corrosion products at the specimen/resin crevices, around barnacles and around mussel byssus threads.

  3. General and Localized Corrosion of Outer Barrier of High-Level Waste Container in Yucca Mountain

    SciTech Connect

    Farmer, J.; McCright, D.; Gdowski, G.; Wang, F.; Summers, T.; Bedrossian, P.; Horn, J.; Lian, T.; Estill, J.; Lingenfelter, A.; Halsey, W.

    2000-05-02

    As described in the License Application Design Selection Report, the recommended waste, package design is Engineering Design Alternative II (CRWMS M&O 1999). This design includes a double-wall waste package (WP) underneath a protective drip shield (DS). purpose and scope of the process-level model described here is to account for both general and localized corrosion of the waste package outer barrier (WPOB), which assumed to be Alloy 22 (UNS N06022-21Cr-13Mo-4Fe-3W-2C-Ni) (ASTM 1997a). This model will include several sub-models, which will account for dry oxidation (DOX), humid air corrosion (HAC), general corrosion (GC) in the aqueous phase, and localized corrosion (LC) the aqueous phase. This model serves as a feed to the waste package degradation (WAPDEG) code for performance, assessment.

  4. A FRAMEWORK FOR THE ANALYSIS OF LOCALIZED CORROSION AT THE PROPOSED YUCCA MOUNTAIN REPOSITORY

    SciTech Connect

    J.H. Payer; S.A. Carroll; G.E. Gdowski; R.B. Rebak

    2006-03-09

    The proposed Yucca Mountain Repository presents a familiar materials performance application that is regularly encountered in energy, transportation and other industries. The widely accepted approach to dealing with materials performance is to identify the performance requirements, to determine the operating conditions to which materials will be exposed and to select materials of construction that perform well in those conditions. A special feature of the proposed Repository is the extremely long time frame of interest, i.e. 10,000's of years and longer. Thus, the time evolution of the environment in contact with waste package surfaces and the time evolution of corrosion damage that may result are of primary interest in the determination of expected performance. An approach is presented to the analysis of localized corrosion during a time period when it is possible for waters from drips and seepage to contact the waste package surfaces, and the analysis is demonstrated for the water chemistry of mixed salt solutions and a set of time-temperature-relative humidity profiles for a hot, mid and cool temperature waste package. Based on the analysis, there are large time periods when localized corrosion can not be supported, and no corrosion damage will occur. Further analysis can then focus on time periods when it is possible for localized corrosion to occur and the determination of the evolution of any corrosion damage.

  5. A Framework for the Analysis of Localized Corrosion at the Proposed Yucca Mountain Repository

    SciTech Connect

    Payer, J H; Carroll, S A; Gdowski, G E; Rebak, R B; Michels, T C; Miller, M C; Henson, V E

    2006-01-10

    The proposed Repository presents a familiar materials performance application that is regularly encountered in energy, transportation and other industries. The widely accepted approach to dealing with materials performance is to identify the performance requirements, to determine the operating conditions to which materials will be exposed and to select materials of construction that perform well in those conditions. A special feature of the proposed Yucca Mountain Repository is the extremely long time frame of interest, i.e. 10,000's of years and longer. Thus, the time evolution of the environment in contact with waste package surfaces and the time evolution of corrosion damage that may result are of primary interest in the determination of expected performance. An approach is presented to the analysis of localized corrosion during a time period when it is possible for waters from drips and seepage to contact the waste package surfaces, and the analysis is demonstrated for the water chemistry of mixed salt solutions and a set of time-temperature-relative humidity profiles for a hot, mid and cool temperature waste package. Based on the analysis, there are large time periods when localized corrosion can not be supported, and no corrosion damage will occur. Further analysis can then focus on time periods when it is possible for localized corrosion to occur and the determination of the evolution of any corrosion damage.

  6. Electrochemical anodizing treatment to enhance localized corrosion resistance of pure titanium.

    PubMed

    Prando, Davide; Brenna, Andrea; Bolzoni, Fabio M; Diamanti, Maria V; Pedeferri, Mariapia; Ormellese, Marco

    2017-01-26

    Titanium has outstanding corrosion resistance due to the thin protective oxide layer that is formed on its surface. Nevertheless, in harsh and severe environments, pure titanium may suffer localized corrosion. In those conditions, costly titanium alloys containing palladium, nickel and molybdenum are used. This purpose investigated how it is possible to control corrosion, at lower cost, by electrochemical surface treatment on pure titanium, increasing the thickness of the natural oxide layer. Anodic oxidation was performed on titanium by immersion in H2SO4 solution and applying voltages ranging from 10 to 80 V. Different anodic current densities were considered. Potentiodynamic tests in chloride- and fluoride-containing solutions were carried out on anodized titanium to determine the pitting potential. All tested anodizing treatments increased corrosion resistance of pure titanium, but never reached the performance of titanium alloys. The best corrosion behavior was obtained on titanium anodized at voltages lower than 40 V at 20 mA/cm2. Titanium samples anodized at low cell voltage were seen to give high corrosion resistance in chloride- and fluoride-containing solutions. Electrolyte bath and anodic current density have little effect on the corrosion behavior.

  7. Study and Modeling of the Localized Nature of Top of the Line Corrosion

    NASA Astrophysics Data System (ADS)

    Singer, Marc

    The occurrence of localized corrosion in Top of the Line Corrosion (TLC) was investigated both in sweet (CO2-dominated) and sour (H 2S-dominated) environments. The focus of the work was to understand the influence of the environmental parameters on localized corrosion at the top of the line in order to develop a narrative of the mechanism. The first part of this project presents the unique setup developed for the experimental work. Several large scale flow loops were used to perform the tests in order to recreate the field environments as closely as possible. The test section was designed using a carbon steel insert exposed to three different levels of cooling at the same time. This concept was quite successful in simulating realistic localized features. A series of long term exposure (one- to three-month) experiments was conducted to investigate the controlling parameters. The occurrence of localized corrosion could be very clearly correlated to the condensation rate, the gas temperature and the organic acid content. Important observations on the morphology of localized TLC features could be made, providing useful insight on the mechanisms involved. The second part of the study attempted to link the presence or absence of a large droplet on the steel surface to the extent of corrosion occurring underneath it. However, this was not successful as no clear relationship could be established with certainty. Instead, the water condensation rate was thought to control the corrosion and the overall aggressiveness of the environment (CO2, acetic acid). Finally, a modeling approach was proposed for the prediction of the localized attack in a top of the line corrosion scenario. The method was based on the observations made during the experimental part of the work and presented a mechanism for the prediction of the onset and propagation of localized corrosion. The FeCO3 saturation level played a key role in defining the overall corrosiveness of the condensed water, while the

  8. DETERMINATION OF CORROSION INHIBITOR CRITERIA FOR TYPE III IIIA TANKS DURING SALT DISSOLUTION OPERATIONS

    SciTech Connect

    Wiersma, B

    2008-01-04

    Preparation of high level waste for vitrification involves in part the dissolution of salt cake from the carbon steel storage tanks. The salt crystals composing this cake are high in nitrate concentration with the interstitial liquid being high in hydroxide and nitrite concentration. During the salt dissolution process, a stage is reached in which the inhibitors, hydroxide and nitrite, are insufficient to prevent nitrate stress corrosion cracking (SCC) and fall outside the requirements of the corrosion control program. Additional inhibitors, which are necessary to meet the requirements, may be counterproductive to the efficiency of the process and waste minimization. Corrosion testing was initiated to better characterize the necessary inhibitor concentration for high nitrate waste during salt dissolution processing. A four-phase test program is being conducted: (1) electrochemical characterization, (2) accelerated or polarized U-bend testing, (3) long-term (non-polarized) U-bend testing and (4) vapor space U-bend tests. Electrochemical testing, which included cyclic potentiodynamic polarization (CPP), linear polarization resistance (LPR) and open-circuit potential (OCP) measurements, was performed to identify stress corrosion cracking susceptibility, to characterize pitting resistance and to determine the general corrosion rate. Polarized U-bend tests were utilized to assess the effect of minimum inhibitor concentrations and heat treatment on SCC and to determine test parameters for future long-term U-bend testing. Results from CPP, LPR and OCP tests demonstrated that carbon steel formed a protective oxide film and the potential became electropositive during exposure to the waste at all inhibitor concentrations. The tenacity of this film improved as the inhibitor concentration level was increased and the temperature was decreased. This passive film increased the resistance to localized corrosion significantly. Therefore if any of these inhibitor levels are selected

  9. Corrosion in the oral cavity--potential local and systemic effects.

    PubMed

    Bergman, M

    1986-03-01

    The main current-generating corrosion cells in the oral cavity are the bimetallic cell and the concentration cell, the latter mainly occurring due to differences in access to oxygen in the various parts of the metallic material. Corrosion resistance is not an intrinsic property of a metal or an alloy for it depends on an interaction with the environment. Thus, the contents of the oral cavity, have a decisive influence. This implies that corrosion tests in vitro are of limited value in predicting the clinical corrosion behaviour of a metallic material. Results from a series of clinical studies concerning a possible relationship between galvanic currents and certain oral and other symptoms in a group of patients who had been referred to the Faculty of Odontology, University of Umeå, are briefly presented. The possibility of local and systemic effects of intra-oral galvanic cells is discussed.

  10. General and Localized Corrosion of Borated Stainless Steels

    SciTech Connect

    T.E. Lister; Ronald E. Mizia; A.W. Erickson; T.L. Trowbridge; B. S. Matteson

    2008-03-01

    The Transportation, Aging and Disposal (TAD) canister-based system is being proposed to transport and store spent nuclear fuel at the Monitored Geologic Repository (MGR) located at Yucca Mountain, Nevada. The preliminary design of this system identifies borated stainless steel as the neutron absorber material that will be used to fabricate fuel basket inserts for nuclear criticality control. This paper discusses corrosion test results for verifying the performance of this material manufactured to the requirements of ASTM A887, Grade A, under the expected repository conditions.

  11. Structural health monitoring of localized internal corrosion in high temperature piping for oil industry

    NASA Astrophysics Data System (ADS)

    Eason, Thomas J.; Bond, Leonard J.; Lozev, Mark G.

    2015-03-01

    Crude oil is becoming more corrosive with higher sulfur concentration, chloride concentration, and acidity. The increasing presence of naphthenic acids in oils with various environmental conditions at temperatures between 150°C and 400°C can lead to different internal degradation morphologies in refineries that are uniform, non-uniform, or localized pitting. Improved corrosion measurement technology is needed to better quantify the integrity risk associated with refining crude oils of higher acid concentration. This paper first reports a consolidated review of corrosion inspection technology to establish the foundation for structural health monitoring of localized internal corrosion in high temperature piping. An approach under investigation is to employ flexible ultrasonic thin-film piezoelectric transducer arrays fabricated by the sol-gel manufacturing process for monitoring localized internal corrosion at temperatures up to 400°C. A statistical analysis of sol-gel transducer measurement accuracy using various time of flight thickness calculation algorithms on a flat calibration block is demonstrated.

  12. Electrochemical study of resistance to localized corrosion of stainless steels for biomaterial applications

    SciTech Connect

    Pan, J.; Karlen, C.; Ulfvin, C.

    2000-03-01

    Sandvik Bioline High-N and 316 LVM are two austenitic stainless steels especially developed for biomaterial applications. Their resistance to localized corrosion was investigated by electrochemical methods including cyclic potentiodynamic polarization and potentiostatic polarization measurements in a phosphate-buffered saline solution and in a simulated crevice solution, i.e., designed for crevice corrosion testing. Sandvik SAF 2507 (a high-performance super duplex stainless steel) was included in the tests as a reference material High-N, higher alloyed than 316 LVM, demonstrated excellent resistance to pitting initiation and a strong tendency to repassivation. High-N proved to have an equivalent or even higher resistance to localized corrosion than SAF 2507. The latter is known for its impressive corrosion properties, particularly in chloride containing environments. While 316 LVM may run the risk of crevice corrosion in implant applications, the risk seems negligible for High-N. In view of the fact that also the mechanical properties are superior to those of 316 LVM, High-N is a very attractive implant material.

  13. CHARACTERIZATION OF LOCALIZED CORROSION OF COPPER PIPES USED IN DRINKING WATER

    EPA Science Inventory

    Localized corrosion of copper, or "copper pitting" in water distribution tubing is a large problem at many utilities. Pitting can lead to pinhole leaks less than a year. Tubing affected by copper pitting will often fail in ultiple locations, resulting in a frustrating situation ...

  14. The Effect of Phosphate on the Morphological and Spectroscopic Properties of Copper Pipes Experiencing Localized Corrosion

    EPA Science Inventory

    Extensive localized or pitting corrosion of copper pipes used in household drinking-water plumbing can eventually lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. A growing number of problems have been associated with high pH and low ...

  15. CHARACTERIZATION OF LOCALIZED CORROSION OF COPPER PIPES USED IN DRINKING WATER

    EPA Science Inventory

    Localized corrosion of copper, or "copper pitting" in water distribution tubing is a large problem at many utilities. Pitting can lead to pinhole leaks less than a year. Tubing affected by copper pitting will often fail in ultiple locations, resulting in a frustrating situation ...

  16. The Effect of Phosphate on the Morphological and Spectroscopic Properties of Copper Pipes Experiencing Localized Corrosion

    EPA Science Inventory

    Extensive localized or pitting corrosion of copper pipes used in household drinking-water plumbing can eventually lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. A growing number of problems have been associated with high pH and low ...

  17. Alpha localized radiolysis and corrosion mechanisms at the iron/water interface: Role of molecular species

    NASA Astrophysics Data System (ADS)

    Vandenborre, Johan; Crumière, Francis; Blain, Guillaume; Essehli, Rachid; Humbert, Bernard; Fattahi, Massoud

    2013-02-01

    This paper is devoted to the iron corrosion phenomena induced by the α (4He2+) water radiolysis species studied in conjunction with the production/consumption of H2 at the solid/solution interface. On one hand, the solid surface is characterized during the 4He2+ ions irradiation by in situ Raman spectroscopy; on another hand, the H2 gas produced by the water radiolysis is monitored by ex situ gas measurements. The 4He2+ ions irradiation experiments are provided either by the CEMHTI (E = 5.0 MeV) either by the ARRONAX (E = 64.7 MeV) cyclotron facilities. The iron corrosion occurs only under irradiation and can be slowed down by H2 reductive atmosphere. Pure iron and carbon steel solids are studied in order to show two distinct behaviors of these surfaces vs. the 4He2+ ions water irradiation: the corrosion products identified are the magnetite phase (Fe(II)Fe(III)2O4) correlated to an H2 consumption for pure iron and the lepidocrocite phase (γ-Fe(III)OOH) correlated to an H2 production for carbon steel sample. This paper underlined the correlation between the iron corrosion products formation onto the solid surface and the H2 production/consumption mechanisms. H2O2 species is considered as the single water radiolytic species involved into the corrosion reaction at the solid surface with an essential role in the oxidation reaction of the iron surface. We propose to bring some light to these mechanisms, in particular the H2 and H2O2 roles, by the in situ Raman spectroscopy during and after the 4He2+ ions beam irradiation. This in situ experiment avoids the evolution of the solid surface, in particular phases which are reactive to the oxidation processing.

  18. Probabilistic methodology to estimate environmental conditions for localized corrosion and stress corrosion cracking of Alloy 22 in a high-level radioactive waste repository setting

    NASA Astrophysics Data System (ADS)

    Pensado, Osvaldo; Pabalan, Roberto

    2008-11-01

    The US Department of Energy (DOE) has indicated that it may use Alloy 22 (Ni-22Cr-13Mo-4Fe-3W) as the waste package outer container material for the potential high-level waste repository at Yucca Mountain, Nevada. This alloy could be susceptible to localized corrosion, in the form of crevice corrosion, and stress corrosion cracking if environmental conditions and material requirements (e.g., existence of crevices or high enough tensile stresses) are met. An approach is proposed to assess the likelihood of environmental conditions capable of inducing crevice corrosion or stress corrosion cracking in Alloy 22. The approach is based on thermodynamic simulations of evaporation of porewaters and published equations to compute corrosion potential and critical potentials for crevice corrosion and stress corrosion cracking as functions of pH, ionic concentration, temperature, and metallurgical states from fabrication processes. Examples are presented to show how the approach can be used in system-level assessment of repository performance.

  19. A FRAMEWORK FOR THE ANALYSIS OF LOCALIZED CORROSION AT THE PROPOSED YUCCA MOUNTAIN REPOSITORY

    SciTech Connect

    Dr. J.H. Payer

    2006-04-18

    Corrosion is a primary determinant of waste package performance at the proposed Yucca Mountain Repository: (1) the most likely degradation process; (2) controls the delay time for radionuclide transport from the waste package; and (3) determines when packages will be penetrated and the shape size and distribution of those penetrations. In this presentation a framework for the analysis of localized corrosion is presented and demonstrated for a scenario: (1) water chemistry of mixed salt solutions (sodium chloride-potassium nitrate); and (2) time-temperature-relative humidity profiles for a hot, mid and cool temperature waste package.

  20. Localized corrosion behaviour in simulated human body fluids of commercial Ni-Ti orthodontic wires.

    PubMed

    Rondelli, G; Vicentini, B

    1999-04-01

    The corrosion performances in simulated human body fluids of commercial equiatomic Ni-Ti orthodontic wires having various shape and size and produced by different manufacturers were evaluated; for comparison purposes wires made of stainless steel and of cobalt-based alloy were also examined. Potentiodynamic tests in artificial saliva at 40 degrees C indicated a sufficient pitting resistance for the Ni-Ti wires, similar to that of cobalt-based alloy wire; the stainless steel wire, instead, exhibited low pitting potential. Potentiodynamic tests at 40 degrees C in isotonic saline solution (0.9% NaCl) showed, for Ni-Ti and stainless steel wires, pitting potential values in the range approximately 200-400 mV and approximately 350 mV versus SCE, respectively: consequently, according to literature data (Hoar TP, Mears DC. Proc Roy Soc A 1996;294:486-510), these materials should be considered potentially susceptible to pitting; only the cobalt-based alloy should be immune from pitting. The localized corrosion potentials determined in the same environment by the ASTM F746 test (approximately 0-200 mV and 130 mV versus SCE for Ni-Ti and stainless steel, respectively) pointed out that for these materials an even higher risk of localized corrosion. Slight differences in localized corrosion behaviour among the various Ni-Ti wires were detected.

  1. Laboratory Evaluation of an Electrochemical Noise System for Detection of Localized and General Corrosion of Natural Gas Transmission Pipelines

    SciTech Connect

    Bullard, S.J.; Covino, B.S., Jr.; Russell, J.H.; Holcomb, G.R.; Cramer, S.D.; Ziomek-Moroz, M.; Eden, D.

    2003-03-16

    Gas transmission pipelines are susceptible to both internal (gas side) and external (soil side) corrosion attack. Internal corrosion is caused by the presence of salt laden moisture, CO{sub 2}, H{sub 2}S, and perhaps O{sub 2} in the natural gas. Internal corrosion usually manifests itself as general corrosion. However, the presence of chlorides in entrained water also can lead to pitting corrosion damage. The electrochemical noise technique can differentiate general from localized corrosion and provide estimates of corrosion rates without external perturbation of the corroding system. It is increasingly being applied to field and industrial installations for in situ corrosion monitoring. It has been used here to determine its suitability for monitoring internal and external corrosion damage on gas transmission pipelines. Corrosion measurements were made in three types of environments: (1) aqueous solutions typical of those found within gas pipelines in equilibrium with th e corrosive components of natural gas; (2) biologically-active soils typical of wetlands; and (3) a simulated, unpressurized, internal gas/liquid gas pipeline environment. Multiple sensor designs were evaluated in the simulated pipe environment. Gravimetric measurements were conducted in parallel with the electrochemical noise measurements to validate the results.

  2. Study of localized corrosion in aluminum alloys by the scanning reference electrode technique

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1995-01-01

    Localized corrosion in 2219-T87 aluminum (Al) alloy, 2195 aluminum-lithium (Al-Li) alloy, and welded 2195 Al-Li alloy (4043 filler) have been investigated using the relatively new scanning reference electrode technique (SRET). Anodic sites are more frequent and of greater strength in the 2195 Al-Li alloy than in the 2219-T87 Al alloy, indicating a greater tendency toward pitting for the latter. However, the overall corrosion rates are about the same for these two alloys, as determined using the polarization resistance technique. In the welded 2195 Al-Li alloy, the weld bean is entirely cathodic, with rather strongly anodic heat affected zones (HAZ) bordering both sides, indicating a high probability of corrosion in the HAZ parallel to the weld bead.

  3. Mitigating Localized Corrosion Using Thermally Sprayed Aluminum (TSA) Coatings on Welded 25% Cr Superduplex Stainless Steel

    NASA Astrophysics Data System (ADS)

    Paul, S.; Lu, Q.; Harvey, M. D. F.

    2015-04-01

    Thermally sprayed aluminum (TSA) coating has been increasingly used for the protection of carbon steel offshore structures, topside equipment, and flowlines/pipelines exposed to both marine atmospheres and seawater immersion conditions. In this paper, the effectiveness of TSA coatings in preventing localized corrosion, such as pitting and crevice corrosion of 25% Cr superduplex stainless steel (SDSS) in subsea applications, has been investigated. Welded 25% Cr SDSS (coated and uncoated) with and without defects, and surfaces coated with epoxy paint were also examined. Pitting and crevice corrosion tests, on welded 25% Cr SDSS specimens with and without TSA/epoxy coatings, were conducted in recirculated, aerated, and synthetic seawater at 90 °C for 90 days. The tests were carried out at both the free corrosion potentials and an applied cathodic potential of -1100 mV saturated calomel electrode. The acidity (pH) of the test solution was monitored daily and adjusted to between pH 7.5 and 8.1, using dilute HCl solution or dilute NaOH, depending on the pH of the solution measured during the test. The test results demonstrated that TSA prevented pitting and crevice corrosion of 25% Cr SDSS in artificial seawater at 90 °C, even when 10-mm-diameter coating defect exposing the underlying steel was present.

  4. Measurements and mechanisms of localized aqueous corrosion in aluminum-lithium alloys

    NASA Technical Reports Server (NTRS)

    Buchheit, Rudolph G., Jr.; Stoner, Glenn E.

    1990-01-01

    Like most heat treatable aluminum alloys, localized corrosion and stress corrosion of Al-Li-Cu alloys is strongly dependent on the nature and distribution of second phase particles. To develop a mechanistic understanding of the role of localized corrosion in the stress corrosion process, bulk samples of T(sub 1) (Al2CuLi) and a range of Al-Cu-Fe impurity phases were prepared for electrochemical experiments. Potentiodynamic polarization and galvanic couple experiments were performed in standard 0.6 M NaCl and in simulated crevice solutions to assess corrosion behavior of these particles with respect to the alpha-Al matrix. A comparison of time to failure versus applied potential using a constant load, smooth bar SCC test technique in Cl(-), Cl(-)/CrO4(2-), and Cl(-)/CO3(2-) environments shows that rapid failures are to be expected when applied potentials are more positive than the breakaway potential (E sub br) of T(sub 1) (crack tip) but less than E(sub br) of alpha-Al (crack walls). It is shown that this criterion is not satisfied in aerated Cl(-) solutions. Accordingly, SCC resistance is good. This criterion is satisfied, however, in an alkaline isolated fissure exposed to a CO2 containing atmosphere. Rapid failure induced by these fissures was recently termed preexposure embrittlement. Anodic polarization shows that the corrosion behavior of T(sub 1) is relatively unaffected in alkaline CO3(2-) environments but the alpha-Al phase is rapidly passivated. X ray diffraction of crevice walls from artificial crevices suggests that passivation of alpha-Al occurs as hydrotalcite-type compound (LiAl2(OH)6)2(+) - CO3(2-) - nH2O.

  5. Localized Corrosion of Alloy 22 -Fabrication Effects-FY05 Summary Report

    SciTech Connect

    Rebak, R B

    2005-10-06

    This report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats of Alloy 22 for container fabrication. Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual repository environments in Yucca Mountain. For example, to determine the intergranular attack in the heat affected zone of a weldment, tests are conducted in boiling acidic and oxidizing solutions according to ASTM standards. These solutions are used to compare the behavior of differently treated metallic coupons. Similarly for electrochemical tests many times pure sodium chloride or calcium chloride solutions are used. Pure chloride solutions are not representative of the repository environment. (1) Surface Stress Mitigation--When metallic plates are welded, for example using the Gas Tungsten Arc Welding (GTAW) method, residual tensile stresses may develop in the vicinity of the weld seam. Processes such as Low Plasticity Burnishing (LPB) and Laser Shock Peening (LSP) could be applied locally to eliminate the residual stresses produced by welding. In this study, Alloy 22 plates were welded and then the above-mentioned surface treatments were applied to eliminate the residual tensile stresses. The aim of the current study was to comparatively test the corrosion behavior of as-welded (ASW) plates with the corrosion behavior of plates with stress mitigated surfaces. Immersion and electrochemical tests were performed. Results from both immersion and electrochemical corrosion tests show that the corrosion resistance of the mitigated plates was not affected by the surface treatments applied. (2) Behavior of Specimens from a Mockup container--Alloy 22 has been extensively tested for

  6. Localized corrosion and stress corrosion cracking of candidate materials for high-level radioactive waste disposal containers in the US: A literature review

    SciTech Connect

    Farmer, J.C.; McCright, R.D.

    1988-11-04

    Container materials may undergo any of several modes of degradation in this environment, including: undesirable phase transformations due to lack of phase stability; atmospheric oxidation; general aqueous corrosion; pitting; crevice corrosion; intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This paper is an analysis of data from the literature relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of these alloys. Though all three austenitic candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these forms of localized attack. Both types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented for Alloy 825 under comparable conditions. Gamma irradiation has been found to enhance SCC of Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while microbiologically induced corrosion effects have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. Of the copper-based alloys, CDA 715 has the best overall resistance to localized attack. Its resistance to pitting is comparable to that of CDA 613 and superior to that of CDA 102. Observed rates of dealloying in CDA 715 are less than those observed in CDA 613 by orders of magnitude. The resistance of CDA 715 to SCC in tarnishing ammonical environments is comparable to that of CDA 102 and superior to that of CDA 613. Its resistance to SCC in nontarnishing ammonical environments is comparable to that of CDA 613 and superior to that of CDA 102. 22 refs., 8 figs., 4 tabs.

  7. Investigations of Localized Corrosion of Stainless Steel after Exposure to Supercritical CO2

    SciTech Connect

    M. Ziomek-Moroz; W. O’Connor; S. Bullard

    2012-03-11

    Severe localized corrosion of a 316 stainless steel autoclave occurred during investigating Type H Portland cement stability in 0.16 M CaCl{sub 2} + 0.02 M MgCl{sub 2} + 0.82 M NaCl brine in contact with supercritical CO{sub 2} containing 4% O{sub 2}. The system operated at 85 C and pressure of 29 MPa. However, no corrosion was observed in the same type of autoclave being exposed to the same environment, containing Type H Portland cement cylindrical samples, also operating at pressure of 29 MPa but at 50 C. The operation time for the 85 C autoclave was 53 days (1272 hours) while that for the 50 C autoclave was 66 days (1584 hours). Debris were collected from the base of both autoclaves and analyzed by X-ray diffraction (XRD). Corrosion products were only found in the debris from the 85 C autoclave. The cement samples were analyzed before and after the exposure by X-ray florescence (XRF) methods. Optical microscopy was used to estimate an extent of the 316 stainless steel corrosion degradation.

  8. Considerations of the Role of the Cathodic Region in Localized Corrosion

    SciTech Connect

    R.G. Kelly; A. Agarwal; F. Cui; X. Shan; U. Landau; J.H. Payer

    2006-03-17

    The ability of wetted cathodes of limited area to support localized corrosion sites on passive materials exposed to atmospheric conditions was studied computationally. The analysis pertains to conditions where metal surfaces are covered by thin layers of moisture in contrast to conditions of full immersion. The moisture may be a continuous layer or in patches with and without particulate on the surface. These conditions are of interest for the surfaces of the waste packages at the proposed Yucca Mountain Repository where waste packages are supported in air. The cathode capacity was characterized by the total net cathodic current, I{sub net}, which the surface surrounding a localized corrosion site (i.e., a pit or crevice) could supply. The cathode capacity increases with increasing cathode area, but it saturates at finite cathode sizes due to the resistance of the thin electrolyte layer. The magnitude of the capacity depends on the water layer thickness, the solution conductivity, and the electrochemical reaction kinetics. The presence of particulates is treated by considering both volume and surface coverage effects. The limited electrolyte volume under thin film conditions can lead to rapid pH changes which decrease the cathode capacity due to the slower electrochemical kinetics at elevated pH. These effects can make localized corrosion less likely to be sustained.

  9. The role of local strains from prior cold work on stress corrosion cracking

    NASA Astrophysics Data System (ADS)

    Ulaganathan, Jaganathan

    Several studies have recently reported that cold working exacerbates stress corrosion cracking (SCC) of materials in various environments, including those in which they were previously thought to be immune. While these studies usually consider cold work as a homogeneous effect, the presence of grain boundaries results in local strain concentrations that are inhomogeneously distributed within the microstructure. In order to understand the underlying mechanisms by which the local strains generated by cold work influences SCC, α-brass and Alloy 600 were used in this study. The microscopic changes in the local strains caused by cold work and by SCC were measured using electron backscatter diffraction (EBSD) and polychromatic X-ray microdiffraction (PXM). While the plastic strains were qualitatively expressed through the local misorientation calculated from the orientation data measured by both EBSD and PXM, the elastic strains were determined from the Laue patterns measured by PXM. The interaction between the local strains, and the crack initiation and propagation during SCC was studied by comparing the strain distribution from the same area measured before cold work, after cold work, and again after SCC. In this way, apart from obtaining insights on the interaction, the relative importance of pre-existing strain concentrations and those created by crack propagation can be identified. Additionally, statistical analysis of the EBSD data from uncracked and cracked grain boundaries in Alloy 600 showed the susceptibility of the boundaries to increase when they were surrounded by high local strain concentrations and when the grains sharing the boundary had similar deformation tendency, but to be independent of the grain boundary angle. Finally, one of the contributors for the changes in the strain distribution during SCC can be the corrosion process itself which was examined by intermittently measuring the changes in local strains caused by intergranular corrosion on an

  10. The Effect of Inhibitors on the Susceptibility of Al 6013/SiC Interface to Localized Corrosion

    NASA Astrophysics Data System (ADS)

    Ahmad, Zaki; Aleem, B. J. Abdul

    2009-03-01

    Al 6013-20 SiC (p) in tempers T4, O, and F is sensitive to localized corrosion in 3.5 wt.% NaCl because of the preponderance of the secondary phase particles of Cu, Fe, and Cr at the Al/SiC interface. Treatment with cerium chloride effectively inhibited the localized corrosion of the alloy by suppressing the cathodic reactions at Al 6013/SiC interface as shown by electrochemical investigations. Morphological studies showed the formation of a protective cerium oxide/hydroxide films, which suppresses the corrosion of the alloy.

  11. Effects of nitrogen in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel welding joint

    NASA Astrophysics Data System (ADS)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhou, Chao

    2017-05-01

    The effects of nitrogen addition in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel (DSS) welds were studied. N2-supplemented shielding gas facilitated the primary austenite formation, suppressed the Cr2N precipitation in weld root, and increased the microhardnesses of weld metal. Furthermore, N2-supplemented shielding gas increased pitting resistance equivalent number (PREN) of austenite, but which decreased slightly PREN of ferrite. The modified double loop electrochemical potentiokinetic reactivation in 2 M H2SO4 + 1 M HCl was an effective method to study the localized corrosion of the different zones in the DSS welds. The adding 2% N2 to pure Ar shielding gas improved the localized corrosion resistance in the DSS welds, which was due to compensation for nitrogen loss and promoting nitrogen further solution in the austenite phases, suppression of the Cr2N precipitation in the weld root, and increase of primary austenite content with higher PREN than the ferrite and secondary austenite. Secondary austenite are prone to selective corrosion because of lower PREN compared with ferrite and primary austenite. Cr2N precipitation in the pure Ar shielding weld root and heat affected zone caused the pitting corrosion within the ferrite and the intergranular corrosion at the ferrite boundary. In addition, sigma and M23C6 precipitation resulted in the intergranular corrosion at the ferrite boundary.

  12. COMPUTATION MODELING OF LOCALIZED CORROSION STABILITY ON WETTED SS316L AT 25 AND 95 DEGREE C

    SciTech Connect

    F. Cuti; F.J. Presuel-Moreno; R.G. Kelly

    2005-10-13

    For corrosion resistant materials exposed to low-temperature atmospheric environments, the corrosion mode of highest risk is expected to be localized corrosion (pitting, crevice, stress-corrosion cracking) due to accumulation of aggressive species within thin solution layers and/or formation of occluded local geometries. The stability of such a localized corrosion site requires that the corroding site (anode) must dissolve at a sufficient high rate to maintain the critical chemistry, and a robust cathodic area (cathode) must exist that can provide sufficient cathodic current. The characteristics of both the anode and the cathode depend on a large number of physiochemical variables (e.g., temperature, ionic concentration, water layer thickness, etc) and electrochemical parameters (i.e., cathodic and anodic polarization behavior). The effects of all these parameters add significantly to the dimensionality of the problem and a systematic study of these parameters is thus more tractable computationally than experimentally. The objective of this study was to computationally characterize the stability of such a local corrosion site and explore the effects of physiochemical and electrochemical parameters on that stability. The overall goal is to contribute to the establishment of a scientific basis for the prediction of the stabilization of localized attack on wetted, corrosion resistant material surface. A localized corrosion site, illustrated in Figure 1, consists of two parts: (a) the external wetted surface (cathode) and (b) the crevice (anode). This study computationally separated the two and modeled them individually, linking them through the imposition of a common fixed potential at the junction point (i.e., the mouth of the crevice). An objected-oriented computational code, CREVICER, developed at UVa, was extended to study separately both the wet surface (cathode) and the crevice (anode). SS316L was chosen as the material of interest.

  13. Localized corrosion of GaAs surfaces and formation of porous GaAs

    SciTech Connect

    Schmuki, P.; Vitus, C.M.; Isaacs, H.S.; Fraser, J.; Graham, M.J.

    1995-12-01

    The present work deals with pitting corrosion of p- and n-type GaAs (100). Pit growth can be electrochemically initiated on both conduction types in chloride-containing solutions and leads after extended periods of time to the formation of a porous GaAs structure. In the case of p-type material, localized corrosion is only observed if a passivating film is present on the surface, otherwise -- e.g. in acidic solutions -- the material suffers from a uniform attack (electropolishing) which is independent of the anion present. In contrast, pitting corrosion of n-type material can be triggered independent of the presence of an oxide film. This is explained in terms of the different current limiting factor for the differently doped materials (oxide film in the case of the p- and a space charge layer in the case of the n-GaAs). The porous structure was characterized by SEM, EDX and AES, and consists mainly of GaAs. From scratch experiments it is clear that the pit initiation process is strongly influenced by surface defects. For n-type material, AFM investigations show that light induced roughening of the order of several hundred nm occurs under non-passivating conditions. This nm- scale roughening however does not affect the pitting process.

  14. A mathematical model for localized corrosion in steam generator crevices under heat transfer conditions

    SciTech Connect

    Engelhardt, G.; Urquidi-Macdonald, M.; Sikora, J.; Macdonald, D.D.; Millett, P.J.

    1995-12-31

    A predictive and self-consistent mathematical model has been developed to describe the localized corrosion in steam generators. The model recognizes that the internal and external environment are coupled by the need to conserve charge in the system. Thus, solution of Laplace`s equation for the external environment (outside the crevice) provides the boundary condition for the electric potential at the crevice mouth, which is needed for solving the system of mass transfer equations for the internal environment (inside the crevice). Mass transfer by diffusion, ion migration, and convection was considered. Heat and momentum transfer equations are solved simultaneously, with the mass balance equation for each species and the condition of electroneutrality inside the cavity being considered. The model takes into account the porosity and tortuosity in the corrosion product deposit in the crevice. The homogeneous chemical reactions (hydrolysis of the products of the anodic reaction and the autoprotolysis of water) are included in the model. The model, in this preliminary form predicts the solution chemistry, potential drop, and temperature distribution inside the crevice. An order of magnitude estimate of the crevice corrosion rate also obtained. At this point, the model predicts only the steady state solution, but it is recognized that a steady state may not exist under normal conditions.

  15. Localized Corrosion of a Neutron Absorbing Ni-Cr-Mo-Gd Alloy

    SciTech Connect

    R.E. Mizia; T. E. Lister; P. J. Pinhero; T. L. Trowbridge

    2005-04-01

    The National Spent Nuclear Fuel Program, located at the Idaho National Laboratory (INL), has developed a new nickel-chromium-molybdenum-gadolinium structural alloy for storage and long-term disposal of spent nuclear fuel (SNF). The new alloy will be used for SNF storage container inserts for nuclear criticality control. Gadolinium has been chosen as the neutron absorption alloying element due to its high thermal neutron absorption cross section. This alloy must be resistant to localized corrosion when exposed to postulated Yucca Mountain in-package chemistries. The corrosion resistance properties of three experimental heats of this alloy are presented. The alloys performance are be compared to Alloy 22 and borated stainless steel. The results show that initially the new Ni-Cr-Mo-Gd alloy is less resistant to corrosion as compared to another Ni-Cr-Mo-Gd alloy (Alloy 22); but when the secondary phase that contains gadolinium (gadolinide) is dissolved, the alloy surface becomes passive. The focus of this work is to qualify these gadolinium containing materials for ASME code qualification and acceptance in the Yucca Mountain Repository.

  16. Localized Deformation as a Primary Cause of Irradiation Assisted Stress Corrosion Cracking

    SciTech Connect

    Gary S. Was

    2009-03-31

    The objective of this project is to determine whether deformation mode is a primary factor in the mechanism of irradiation assisted intergranular stress corrosion cracking of austenitic alloys in light watert reactor core components. Deformation mode will be controlled by both the stacking fault energy of the alloy and the degree of irradiation. In order to establish that localized deformation is a major factor in IASCC, the stacking fault energies of the alloys selected for study must be measured. Second, it is completely unknown how dose and SFE trade-off in terms of promoting localized deformation. Finally, it must be established that it is the localized deformation, and not some other factor that drives IASCC.

  17. Synergism of Rare Earth Ce(III) Ion with Cysteine against Corrosion of P110 Carbon Steel in 3% NaCl Solutions

    NASA Astrophysics Data System (ADS)

    Liu, Xia; Yang, Jianshu; Liu, Yongping; Ji, Xiangyun; Lu, Ying; Yuan, Yizhi

    The synergism of CeCl3 (Ce) with cysteine (Cys) on the corrosion of P110 carbon steel in 3% NaCl solutions was investigated by electrochemical methods and surface analysis. The results showed that CeCl3 and cysteine do little to inhibit the corrosion of carbon steel, but the combination of CeCl3 with cysteine has obvious synergistic effect on the corrosion of carbon steel and the corrosion inhibition efficiency was improved significantly. The potentiodynamic polarization curves indicated that the mixture of CeCl3 and cysteine acts as a cathodic inhibitor. Scanning electron microscope (SEM) and Infrared (IR) reflection spectra showed the synergistic inhibition effect was formed by the complexes between rare earth Ce(III) ion and amino acid.

  18. The effects of temperature and aeration on the corrosion of A508III low alloy steel in boric acid solutions at 25-95 °C

    NASA Astrophysics Data System (ADS)

    Xiao, Qian; Lu, Zhanpeng; Chen, Junjie; Yao, Meiyi; Chen, Zhen; Ejaz, Ahsan

    2016-11-01

    The effects of temperature, solution composition and dissolved oxygen on the corrosion rate and electrochemical behavior of an A508III low alloy steel in boric acid solution with lithium hydroxide at 25-95 °C are investigated. In aerated solutions, increasing the boric acid concentration increases the corrosion rate and the anodic current density. The corrosion rate in deaerated solutions increases with increasing temperature. A corrosion rate peak value is found at approximately 75 °C in aerated solutions. Increasing temperature increases the oxygen diffusion coefficient, decreases the dissolved oxygen concentration, accelerates the hydrogen evolution reaction, and accelerates both the active dissolution and the film forming reactions. Increasing dissolved oxygen concentration does not significantly affect the corrosion rate at 50 and 60 °C, increases the corrosion rate at 70 and 80 °C, and decreases the corrosion rate at 87.5 and 95 °C in a high concentration boric acid solution with lithium hydroxide.

  19. Localized dealloying corrosion mediated by self-assembled monolayers used as an inhibitor system.

    PubMed

    Shrestha, B R; Bashir, A; Ankah, G N; Valtiner, M; Renner, F U

    2015-01-01

    The structure and chemistry of thiol or selenol self-assembled organic monolayers have been frequently addressed due to the unique opportunities in functionalization of materials. Such organic films can also act as effective inhibition layers to mitigate oxidation or corrosion. Cu-Au alloy substrates covered by self-assembled monolayers show a different dealloying mechanism compared to bare surfaces. The organic surface layer inhibits dealloying of noble metal alloys by a suppression of surface diffusion at lower potentials but at higher applied potentials dealloying proceeds in localized regions due to passivity breakdown. We present an in situ atomic force microscopy study of a patterned thiol layer applied on Cu-Au alloy surfaces and further explore approaches to change the local composition of the surface layers by exchange of molecules. The pattern for the in situ experiment has been applied by micro-contact printing. This allows the study of corrosion protection with its dependence on different molecule densities at different sites. Low-density thiol areas surrounding the high-density patterns are completely protected and initiation of dealloying proceeds only along the areas with the lowest inhibitor concentration. Dealloying patterns are highly influenced and controlled by molecular thiol to selenol exchange and are also affected by introducing structural defects such as scratches or polishing defects.

  20. Localized Corrosion Susceptibility Of Alloy 22 In Na-K-Cl_NO3 Brines At 110 To 150?C

    SciTech Connect

    Lian, T; Felker, S J; Hailey, P D; Staggs, K J; Gdowski, G E

    2006-03-31

    Electrochemical cyclic potentiodynamic polarization experiments were conducted to assess crevice corrosion of Alloy 22 in de-aerated aqueous solutions of chloride and nitrate salts of potassium and sodium in the temperature range 110-150 C. The tests were run in neutral and slightly acidic aqueous solutions. The Alloy 22 specimens were multiple creviced weld prisms. No evidence of crevice corrosion was observed in the range 125-150 C. In the 120 to 160 C temperature range, the anionic concentration of stable aqueous solutions is dominated by nitrate relative to chloride. At nominally 120 C, the minimum nitrate to chloride ratio is about 4.5, and it increases to about 22 at nominally 155 C. The absence of localized corrosion susceptibility in these solutions is attributed to the known inhibiting effect of the nitrate anion. Aqueous solution chemistry studies indicate that nitrate to chloride ratios of less than 0.5 are possible for temperatures up to nominally 116 C. At 110 C, aqueous solutions can have dissolved chloride well in excess of nitrate. Localized corrosion was observed at nitrate to chloride ratios up to 1.0, the highest ratio tested. The extent of localized corrosion was confined to the crevice region of the samples, and was limited for nitrate to chloride ratios greater than or equal to 0.3.

  1. THE SENSITIVITY OF CARBON STEELS' SUSCEPTIBILITY TO LOCALIZED CORROSION TO THE PH OF NITRATE BASED NUCLEAR WASTES

    SciTech Connect

    BOOMER KD

    2010-01-14

    The Hanford tank reservation contains approximately 50 million gallons of liquid legacy radioactive waste from cold war weapons production, which is stored in 177 underground storage tanks. The tanks will be in use until waste processing operations are completed. The wastes tend to be high pH (over 10) and nitrate based. Under these alkaline conditions carbon steels tend to be passive and undergo relatively slow uniform corrosion. However, the presence of nitrate and other aggressive species, can lead to pitting and stress corrosion cracking. This work is a continuation of previous work that investigated the propensity of steels to suffer pitting and stress corrosion cracking in various waste simulants. The focus of this work is an investigation of the sensitivity of the steels' pitting and stress corrosion cracking susceptibility tosimulant pH. Previous work demonstrated that wastes that are high in aggressive nitrate and low in inhibitory nitrite are susceptible to localized corrosion. However, the previous work involved wastes with pH 12 or higher. The current work involves wastes with lower pH of 10 or 11. It is expected that at these lower pHs that a higher nitrite-to-nitrate ratio will be necessary to ensure tank integrity. This experimental work involved both electrochemical testing, and slow strain rate testing at either the free corrosion potential or under anodic polarization. The results of the current work will be discussed, and compared to work previously presented.

  2. Current and potential distributions in corrosion systems

    SciTech Connect

    Smyrl, W.H.

    1980-01-01

    Current and potential distribution calculations in corrosion are reviewed. The mathematical methods used, and the specific results for galvanic corrosion, cathodic protection, and localized corrosion are described.

  3. A model for prediction of possibility of localized corrosion attack of stainless steels

    SciTech Connect

    Hakkarainen, T.J.

    1996-10-01

    Empirical or semi-empirical relations were developed to express the dependence of the possibility (probability) of localized corrosion attack of various stainless steels on environmental factors. Only chloride induced attack within the range 0--100 C (32--212 F) is considered. The environmental variables considered include temperature, pH, chloride content, sulfate content, presence of oxidizing agents, crevices and deposits, flow rate and possibility of concentration of solution by evaporation. Common mathematical operations are used to formulate the trends into equations. Examples of the predictions of the model are given for type AISI 316 stainless steel in two environments: Baltic Sea water at 25 C and a solution containing 300 mg/l of chloride ions at 70 C.

  4. THE EFFECT OF PHOSPHATE ON THE MORPHOLOGICAL AND SPECTROSCOPIC PROPERTIES OF COPPER DRINKING WATER PIPES EXPERIENCING LOCALIZED CORROSION

    EPA Science Inventory

    Extensive localized or pitting corrosion of copper pipes used in household drinking-water plumbing can eventually lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. A large water system in Florida has been addressing a widespread pinhole...

  5. THE EFFECT OF PHOSPHATE ON THE MORPHOLOGICAL AND SPECTROSCOPIC PROPERTIES OF COPPER DRINKING WATER PIPES EXPERIENCING LOCALIZED CORROSION

    EPA Science Inventory

    Extensive localized or pitting corrosion of copper pipes used in household drinking-water plumbing can eventually lead to pinhole water leaks that may result in water damage, mold growth, and costly repairs. A large water system in Florida has been addressing a widespread pinhole...

  6. Observation of Localized Corrosion of Ni-Based Alloys Using Coupled Orientation Imaging Microscopy and Atomic Force Microscopy

    SciTech Connect

    Bedrossian, P.J.

    1999-11-24

    We present a method for assessing the relative vulnerabilities of distinct classes of grain boundaries to localized corrosion. Orientation imaging microscopy provides a spatial map which identifies and classifies grain boundaries at a metal surface. Once the microstructure of a region of a sample surface has been characterized, a sample can be exposed to repeated cycles of exposure to a corrosive environment alternating with topographic measurement by an atomic force microscope in the same region in which the microstructure had been mapped. When this procedure is applied to Ni and Ni-based alloys, we observe enhanced attack at random grain boundaries relative to special boundaries and twins in a variety of environments.

  7. Effects of brining on the corrosion of ZVI and its subsequent As(III/V) and Se(IV/VI) removal from water.

    PubMed

    Yang, Zhe; Xu, Hui; Shan, Chao; Jiang, Zhao; Pan, Bingcai

    2017-03-01

    Zero-valent iron (ZVI) has been extensively applied in water remediation, and most of the ZVI materials employed in practical applications are iron scraps, which have usually been corroded to certain extent under different conditions. In this study, the effects of brining with six solutions (NaCl, Na2SO4, NaHCO3, Na2SiO3, NH4Cl, and NaH2PO4) on the corrosion of ZVI and its performance in the removal of As(III/V)/Se(IV/VI) were systematically investigated. All the studied solutions enhanced the corrosion of ZVI except for Na2SiO3, and the degrees of corrosion followed the order of NH4Cl > NaH2PO4 > Na2SO4 > NaCl > NaHCO3 > H2O > Na2SiO3. The corrosion products derived from ZVI were identified by SEM and XRD, and the dominant corrosion products varied with the type of brine solution. The positive correlation between the degree of ZVI corrosion and As(III/V)/Se(IV/VI) removal by the pre-corroded ZVI (pcZVI) was verified. In addition, As and Se removal by pcZVI was realized via a comprehensive process including adsorption and reduction, as further supported by the XPS analysis. We believe this study will shed new light upon the selection of iron materials pre-corroded under different saline conditions for practical water remediation.

  8. 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.

  9. The Usefulness of Ultra-High Resolution Microstructural Studies for Understanding Localized Corrosion Behavior of Al Alloys

    SciTech Connect

    Kappes, M.; Kovarik, L.; Mills, Michael J.; Miller, Michael K; Frankel, G. S.

    2008-01-01

    The corrosion behavior of different tempers of two aluminum alloys, AA7050 and an experimental Al-Mg-Cu-Si alloy, was studied in NaCl solution by anodic polarization and scanning electron microscopy and was correlated with differences in the microstructure. Potentiodynamic polarization experiments were performed on samples from the exact sheets used by others to study the microstructure evolution during the early stages of the precipitation sequence by high-resolution characterization tools [i.e., high-resolution transmission electron microscopy and atom probe tomography (APT)]. The usefulness of information from these state-of-the-art tools to lead to a better understanding about the effects of nanoscale segregation on localized corrosion of aluminum alloys is discussed. APT was able to provide information about the composition of the solid solution matrix region between the fine-scale hardening particles, which is not possible by any other technique. Some of the changes in corrosion behavior, e.g., the breakdown potentials, with temper could be rationalized based on changes in the matrix composition. The formation of corrosion-susceptible surface layers on as-polished AA7050 depended on the predominant type of hardening particle. The lack of detailed knowledge of the grain boundary region limited the applicability of the microstructural information generated by previous studies for understanding intergranular corrosion.

  10. The Effect of HVOF Particle-Substrate Interactions on Local Variations in the Coating Microstructure and the Corrosion Resistance

    NASA Astrophysics Data System (ADS)

    Racek, Ondrej

    2010-09-01

    Splashing and redeposition of droplets occur during thermal spray processing, which affects the coating porosity and morphology. Therefore, this phenomenon is important from a practical point of view such as corrosion. Particle interaction with substrate is a function of the particle velocity, viscosity, temperature, as well as the substrate temperature, chemistry, roughness, and geometry. In the present study, the splashing phenomenon was studied on CrC-NiCr and stainless steel materials deposited using the high velocity oxygen fuel process. The effect of particle splashing on the coating microstructure was investigated with respect to the corrosion properties. Particle behavior during impact was explained based on in-flight particle velocity and temperature measurements. It was found that the conditions that favor particle splashing promote occurrence of localized porosity. The localized porosity was a strong function of the substrate curvature and originated from the substrate asperities.

  11. 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.

  12. 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.

  13. Local Area Network Implementation: Moving toward Phase III.

    ERIC Educational Resources Information Center

    Hoehl, Susan B.

    1989-01-01

    Describes a LAN (local area network)-based automation project which has neared completion of the first phase of implementation at the Health Sciences Library of Allegheny General Hospital (Pittsburgh, PA). Changes in the library and its objectives with increased technological experience are examined. Diagrams of the current LAN configuration and…

  14. Translocation of surface-localized effectors in type III secretion

    PubMed Central

    Edgren, Tomas; Wang-Edgren, Helen; Rosqvist, Roland; Fahlgren, Anna; Wolf-Watz, Hans; Fallman, Maria

    2011-01-01

    Pathogenic Yersinia species suppress the host immune response by using a plasmid-encoded type III secretion system (T3SS) to translocate virulence proteins into the cytosol of the target cells. T3SS-dependent protein translocation is believed to occur in one step from the bacterial cytosol to the target-cell cytoplasm through a conduit created by the T3SS upon target cell contact. Here, we report that T3SS substrates on the surface of Yersinia pseudotuberculosis are translocated into target cells. Upon host cell contact, purified YopH coated on Y. pseudotuberculosis was specifically and rapidly translocated across the target-cell membrane, which led to a physiological response in the infected cell. In addition, translocation of externally added YopH required a functional T3SS and a specific translocation domain in the effector protein. Efficient, T3SS-dependent translocation of purified YopH added in vitro was also observed when using coated Salmonella typhimurium strains, which implies that T3SS-mediated translocation of extracellular effector proteins is conserved among T3SS-dependent pathogens. Our results demonstrate that polarized T3SS-dependent translocation of proteins can be achieved through an intermediate extracellular step that can be reconstituted in vitro. These results indicate that translocation can occur by a different mechanism from the assumed single-step conduit model. PMID:21220342

  15. LOCALIZED CORROSION OF AUSTENITIC STAINLESS STEELEXPOSED TO MIXTURES OF PLUTONIUM OXIDE AND CHLORIDE SALTS

    SciTech Connect

    Zapp, P; Kerry Dunn, K; Jonathan Duffey, J; Ron Livingston, R; Zane Nelson, Z

    2008-11-21

    Laboratory corrosion tests were conducted to investigate the corrosivity of moist plutonium oxide/chloride (PuO{sub 2}/Cl-) salt mixtures on 304L and 316L stainless steel coupons. The tests exposed flat coupons for pitting evaluation and 'teardrop' stressed coupons for stress corrosion cracking (SCC) evaluation at room temperature to various mixtures of PuO{sub 2} and chloride-bearing salts for periods up to 500 days. The two flat coupons were placed so that the solid oxide/salt mixture contacted about one half of the coupon surface. One teardrop coupon was placed in contact with solid mixture; the second teardrop was in contact with the headspace gas only. The mixtures were loaded with nominally 0.5 wt % water under a helium atmosphere. Observations of corrosion ranged from superficial staining to pitting and SCC. The extent of corrosion depended on the total salt concentration and on the composition of the salt. The most significant corrosion was found in coupons that were exposed to 98 wt % PuO{sub 2}, 2 wt % chloride salt mixtures that contained calcium chloride. SCC was observed in two 304L stainless steel teardrop coupons exposed in solid contact to a mixture of 98 wt % PuO{sub 2}, 0.9 wt % NaCl, 0.9 wt % KCl, and 0.2 wt % CaCl{sub 2}. The cracking was associated with the heat-affected zone of an autogenous weld that ran across the center of the coupon. Cracking was not observed in coupons exposed to the headspace gas, nor in coupons exposed to other mixtures with either 0.92 wt% CaCl{sub 2} or no CaCl{sub 2}. The corrosion results point to the significance of the interaction between water loading and the concentration of the hydrating salt CaCl{sub 2} in the susceptibility of austenitic stainless steels to corrosion.

  16. Measurement of Localized Corrosion Rates at Inclusion Particles in AA7075 by In Situ Three Dimensional (3D) X-ray Synchrotron Tomography

    SciTech Connect

    Singh, Sudhanshu S.; Williams, Jason J.; Stannard, Tyler J.; Xiao, Xianghui; De Carlo, Francesco; Chawla, Nikhilesh

    2016-03-01

    In situ X-ray synchrotron tomography was used to measure the localized corrosion rate of Mg2Si particles present in 7075 aluminum alloys in deionized ultra-filtered (DIUF) water. The evolution of hydrogen bubbles was captured as a function of time and the measured volume was used to calculate the local corrosion rate of Mg2Si particles. It was shown that in the absence of chloride ions, stress was needed to create fresh particle surfaces, either by fracture or debonding, to initiate corrosion at the particles.

  17. Application of wire beam electrode technique to investigate initiation and propagation of rebar corrosion

    SciTech Connect

    Shi, Wei; Dong, Ze Hua Kong, De Jie; Guo, Xing Peng

    2013-06-15

    Multi-electrode technique named as wire beam electrode (WBE) was used to study pitting corrosion of rebar under concrete cover. When WBE embedded mortar sample was immersed in NaCl solution, uneven distributions of galvanic current and open circuit potential (OCP) on the WBE were observed due to the initiation of pitting corrosion. The following oxygen depletion in mortar facilitated the negative shift of the OCP and the smoothing of the current and potential distributions. Wetting–drying cycle experiments showed that corrosion products instead of oxygen in wet mortar specimen sustained the propagation of pitting corrosion due to Fe (III) taking part in cathodic depolarization during oxygen-deficient wet period, which was confirmed by micro-Raman spectroscopy. In addition, new pitting corrosion occurred mainly near the corrosion products, leading to preferentially horizontal propagation of rust layer on the WBE. A localized corrosion factor was further presented to quantify the localised corrosion based on galvanic current maps.

  18. Electrochemical Noise Sensors for Detection of Localized and General Corrosion of Natural Gas Transmission Pipelines. Final Report for the Period July 2001-October 2002

    SciTech Connect

    Bullard, Sophie J.; Covino, Jr., Bernard S.; Russell, James H.; Holcomb, Gordon R.; Cramer, Stephen D.; Ziomek-Moroz, Margaret

    2002-12-01

    The U.S. Department of Energy, National Energy Technology Laboratory funded a Natural Gas Infrastructure Reliability program directed at increasing and enhancing research and development activities in topics such as remote leak detection, pipe inspection, and repair technologies and materials. The Albany Research Center (ARC), U.S. Department of Energy was funded to study the use of electrochemical noise sensors for detection of localized and general corrosion of natural gas transmission pipelines. As part of this, ARC entered into a collaborative effort with the corrosion sensor industry to demonstrate the capabilities of commercially available remote corrosion sensors for use with the Nation's Gas Transmission Pipeline Infrastructure needs. The goal of the research was to develop an emerging corrosion sensor technology into a monitor for the type and degree of corrosion occurring at key locations in gas transmission pipelines.

  19. pH dependence of Fenton reagent generation and As(III) oxidation and removal by corrosion of zero valent iron in aerated water.

    PubMed

    Katsoyiannis, Ioannis A; Ruettimann, Thomas; Hug, Stephan J

    2008-10-01

    Corrosion of zerovalent iron (ZVI) in oxygen-containing water produces reactive intermediates that can oxidize various organic and inorganic compounds. We investigated the kinetics and mechanism of Fenton reagent generation and As(III) oxidation and removal by ZVI (0.1m2/g) from pH 3-11 in aerated water. Observed half-lives for the oxidation of initially 500 microg/L As(III) by 150 mg Fe(0)/L were 26-80 min at pH 3-9. At pH 11, no As(III) oxidation was observed during the first two hours. Dissolved Fe(III) reached 325, 140, and 6 microM at pH 3, 5, and 7. H2O2 concentrations peaked within 10 min at 1.2, 0.4, and < 0.1 microM at pH 3, 5, and 7, and then decreased to undetectable levels. Addition of 2,2'-bipyridine (1-3 mM), prevented Fe(II) oxidation by O2 and H2O2 and inhibited As(III)oxidation. 2-propanol (14 mM), scavenging OH-radicals, quenched the As(III) oxidation at pH 3, but had almost no effect at pH 5 and 7. Experimental data and kinetic modeling suggest that As(III) was oxidized mainly in solution by the Fenton reaction and removed by sorption on newly formed hydrous ferric oxides. OH-radials are the main oxidant for As(III) at low pH, whereas a more selective oxidant oxidizes As(III) at circumneutral pH.

  20. Investigations of Local Corrosion Behavior of Plasma-Sprayed FeCr Nanocomposite Coating by SECM

    NASA Astrophysics Data System (ADS)

    Shi, Xi; Shu, Mingyong; Zhong, Qingdong; Zhang, Junliang; Zhou, Qiongyu; Bui, Quoc Binh

    2016-02-01

    FeCr alloy coating can be sprayed on low-carbon steel to improve the corrosion resistance because of FeCr alloy's high anti-corrosion capacity. In this paper, Fe microparticles/Cr nanoparticles coating (NFC) and FeCr microparticles coating (MFC) were prepared by atmospheric plasma spraying and NFC was heat-treated under hydrogen atmosphere at 800 °C (HNFC). EDS mapping showed no penetration of Ni in MFC and NFC while penetration of Ni occurred in HNFC. X-ray diffraction results indicated the form of the NiCrFe (bcc) solid solution in HNFC. SECM testing in 3.5 (wt.%) NaCl revealed that the anti-corrosion capacity of NFC improved compared with MFC, while HNFC improved further.

  1. Localized Corrosion Currents from Graphite/Aluminum and Welded SiC/Al Metal Matrix Composites.

    DTIC Science & Technology

    1985-02-28

    the corrosion rate in the absence of flaws might be improved by additions of poisions to the fiber to retard the oxygen reduction reaction on graphite...weidment 8 Al4C3 + 12H 20 + 4Al(OH) 3 + 3CH 4 This reaction, along with other metallurgical variations caused by the heat of welding, leads to...efficient cathodic sites along anodic corrosion paths and can lead to exfoliation in 6061 Al when the inter- metallics are present in an appropriate

  2. Nanoparticle coating on the silane-modified surface of magnesium for local drug delivery and controlled corrosion.

    PubMed

    Lee, Won Seok; Park, Min; Kim, Myung Hun; Park, Chun Gwon; Huh, Beom Kang; Seok, Hyun Kwang; Choy, Young Bin

    2016-01-01

    In this study, we proposed a potential method for the preparation of a magnesium-based medical device for local drug delivery and controlled corrosion. A magnesium surface was modified with 3-aminopropyltrimethoxy silane, and the resulting surface was then coated with drug-loaded nanoparticles made of poly (lactic-co-glycolic acid) via electrophoretic deposition. The drug-loaded nanoparticles (i.e., Tr_NP) exhibited a size of 250 ± 67 nm and a negative zeta potential of -20.9 ± 2.75 mV. The drug was released from the nanoparticles in a sustained manner for 21 days, and this did not change after their coating on the silane-modified magnesium. The silane-modified surface suppressed magnesium corrosion. When immersed in phosphate buffered saline at pH 7.4, the average rate of hydrogen gas generation was 0.41-0.45 ml/cm(2)/day, compared to 0.58-0.6 ml/cm(2)/day from a bare magnesium surface. This corrosion profile was not significantly changed after nanoparticle coating under the conditions employed in this work. The in vitro cell test revealed that the drug released from the coating was effective during the whole release period of 21 days, and both the silane-modified surface and carrier nanoparticles herein were not cytotoxic. © The Author(s) 2015.

  3. Modeling of Membrane-Electrode-Assembly Degradation in Proton-Exchange-Membrane Fuel Cells - Local H2 Starvation and Start-Stop Induced Carbon-Support Corrosion

    NASA Astrophysics Data System (ADS)

    Gu, Wenbin; Yu, Paul T.; Carter, Robert N.; Makharia, Rohit; Gasteiger, Hubert A.

    Carbon-support corrosion causes electrode structure damage and thus electrode degradation. This chapter discusses fundamental models developed to predict cathode carbon-support corrosion induced by local H2 starvation and start-stop in a proton-exchange-membrane (PEM) fuel cell. Kinetic models based on the balance of current among the various electrode reactions are illustrative, yielding much insight on the origin of carbon corrosion and its implications for future materials developments. They are particularly useful in assessing carbon corrosion rates at a quasi-steady-state when an H2-rich region serves as a power source that drives an H2-free region as a load. Coupled kinetic and transport models are essential in predicting when local H2 starvation occurs and how it affects the carbon corrosion rate. They are specifically needed to estimate length scales at which H2 will be depleted and time scales that are valuable for developing mitigation strategies. To predict carbon-support loss distributions over an entire active area, incorporating the electrode pseudo-capacitance appears necessary for situations with shorter residence times such as start-stop events. As carbon-support corrosion is observed under normal transient operations, further model improvement shall be focused on finding the carbon corrosion kinetics associated with voltage cycling and incorporating mechanisms that can quantify voltage decay with carbon-support loss.

  4. Localized corrosion studies on materials proposed for a safety-grade sodium-to- air decay-heat removal system for fast breeder reactors

    NASA Astrophysics Data System (ADS)

    Kamachi Mudali, U.; Khatak, H. S.; Dayal, R. K.; Gnanamoorthy, J. B.

    1993-02-01

    The present investigation was carried out to assess the localized corrosion resistance of materials proposed for the construction of the safety-grade sodium-to-air decay-heat removal system for fast breeder reactors. The materials, such as Alloy 800,9Cr-lMo steel, and type 316LN stainless steel, in different microstructural conditions were assessed for pitting and stress-corrosion cracking resistances in a chloride medium. The results indicated that 9Cr-lMo steel in the normalized and tempered condition can be considered for the above application from the standpoint of corrosion resistance.

  5. Localized corrosion studies on materials proposed for a safety-grade sodium-to-air decay-heat removal system for fast breeder reactors

    SciTech Connect

    Mudali, U.K.; Khatak, H.S.; Dayal, R.K.; Gnanamoorthy, J.B. )

    1993-02-01

    The present investigation was carried out to assess the localized corrosion resistance of materials proposed for the construction of the safety-grade sodium-to-air decay-heat removal system for fast breeder reactors. The materials, such as Alloy 800, 9Cr-1 Mo steel, and type 316LN stainless steel, in different microstructural conditions were assessed for pitting and stress-corrosion cracking resistances in a chloride medium. The results indicated that 9Cr-1Mo steel in the normalized and tempered condition can be considered for the above application from the standpoint of corrosion resistance.

  6. A high-sensitivity scanning magnetometer based on the giant magneto-impedance effect for measuring local magnetic fields of corrosion currents

    NASA Astrophysics Data System (ADS)

    Gudoshnikov, S. A.; Bardin, I. V.; Bautin, V. A.; Nozdrin, A. G.; Popova, A. V.; Prokhorova, Yu. V.; Skomarovskii, V. S.; Lyubimov, B. Ya.; Seferyan, A. G.; Usov, N. A.

    2016-05-01

    The design, main characteristics, and specific features of a new high-sensitivity magnetometer based on the giant magneto-impedance (GMI) effect in amorphous ferromagnetic microwires are considered. It is shown that, in addition to measuring homogeneous fields, the device is capable of detecting weak local magnetic fields of conduction currents and ion currents involved in corrosion processes. Results of in situ magnetic measurements of corrosion processes in the model system of copper-zinc in a sulfuric acid solution qualitatively agree with the data of direct corrosion tests employing the standard gravimetric method.

  7. Azimuthal sound localization in the European starling (Sturnus vulgaris): III. Comparison of sound localization measures.

    PubMed

    Feinkohl, Arne; Borzeszkowski, Katharina M; Klump, Georg M

    2016-02-01

    Sound localization studies have typically employed two types of tasks: absolute tasks that measured the localization of the angular location of a single sound and relative tasks that measured the localization of the angular location of a sound relative to the angular location of another sound from a different source (e.g., in the Minimum Audible Angle task). The present study investigates the localization of single sounds in the European starling (Sturnus vulgaris) with a left/right discrimination paradigm. Localization thresholds of 8-12° determined in starlings using this paradigm were much lower than the minimum audible angle thresholds determined in a previous study with the same individuals. The traditional concept of sound localization classifies the present experiment as an absolute localization task. However, we propose that the experiment presenting single sounds measured localization of the angular location of the sound relative to a non-acoustic spatial frame of reference. We discuss how the properties of the setup can determine if presentation of single sounds in a left/right discrimination paradigm comprises an absolute localization task rather than a localization task relative to a non-acoustic reference. Furthermore, the analysis methods employed may lead to quite different threshold estimates for the same data, especially in case of a response bias in left/right discrimination. We propose using an analysis method precluding effects of response bias on the threshold estimate. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Characterization of Localized Filament Corrosion Products at the Anodic Head on a Model Mg-Zn-Zr Alloy Surface

    DOE PAGES

    Rossouw, David; Fu, Dong; Leonard, Donovan N.; ...

    2017-02-15

    In this study, localized filament corrosion products at the anodic head on a model Mg-1%Zn-0.4%Zr alloy surface were characterized by electron microscopy techniques of site-specific lamella prepared by focused ion beam milling. It is revealed that the anodic head propagates underneath a largely intact thin and dense MgO surface film and comprises dense aggregates of nano-crystalline MgO within a nano-porous Mg(OH)2 network. In conclusion, the findings contribute new supportive direct imaging insight into the source of the enhanced H2 evolution that accompanies anodic dissolution of Mg and its alloys.

  9. DETERMINATION OF CORROSION INHIBITOR CRITERIA FOR TYPE III/IIIA TANKS DURING SALT DISSOLUTION OPERATIONS INTERIM REPORT

    SciTech Connect

    Counts, K; Bruce Wiersma, B; John Mickalonis, J

    2007-12-31

    Preparation of high level waste for vitrification involves in part the dissolution of salt cake from the carbon steel storage tanks. During dissolution, a point is reached in which the corrosion inhibitors, hydroxide and nitrite, are diluted below established guidelines, and nitrate stress corrosion cracking (SCC) is possible. Because the addition of inhibitors may be counterproductive to process efficiency and waste minimization, corrosion testing was initiated to revisit and possibly revise the guidelines for inhibitor limits. The bases for the work summarized in this status report are results from previously-completed phases of study. In the first two phases of study, several reduced-inhibitor levels were tested in HLW simulants with nitrate concentrations ranging from 4.5 M to 8.5 M. The first two phases of work determined, among other things, the reduced-inhibitor levels and solution chemistries in which heat-treated and non-heat-treated A537 carbon steel is susceptible to SCC, crevice corrosion, and pitting. The work covered in this current task both builds on and verifies the conclusions of the previous work. The current work involves testing of low levels of inhibitors in HLW simulants with 5.5 M to 8.5 M nitrate concentrations. Stressed U-bend specimens, both polarized and non-polarized, were tested. Non-polarized U-bend testing is ongoing, with the U-bends currently in test for 100 days. The purpose of the testing is to determine SCC susceptibility in the vapor space (VS) and liquid air interface (LAI) regions of the HLW tanks under conditions expected during salt dissolution, and also to verify previous accelerated testing. The simulated wastes being tested have nitrate concentrations of 5.5 M and 8.5 M and inhibitor levels of 0.01 M/0.01 M hydroxide/nitrite and 0.1 M/ 0.1 M hydroxide/nitrite. The open circuit potential measurements being monitored and the corrosion morphology of the U-bends are in agreement with results and observations of previous

  10. Classification of acoustic emission signals using wavelets and Random Forests : Application to localized corrosion

    NASA Astrophysics Data System (ADS)

    Morizet, N.; Godin, N.; Tang, J.; Maillet, E.; Fregonese, M.; Normand, B.

    2016-03-01

    This paper aims to propose a novel approach to classify acoustic emission (AE) signals deriving from corrosion experiments, even if embedded into a noisy environment. To validate this new methodology, synthetic data are first used throughout an in-depth analysis, comparing Random Forests (RF) to the k-Nearest Neighbor (k-NN) algorithm. Moreover, a new evaluation tool called the alter-class matrix (ACM) is introduced to simulate different degrees of uncertainty on labeled data for supervised classification. Then, tests on real cases involving noise and crevice corrosion are conducted, by preprocessing the waveforms including wavelet denoising and extracting a rich set of features as input of the RF algorithm. To this end, a software called RF-CAM has been developed. Results show that this approach is very efficient on ground truth data and is also very promising on real data, especially for its reliability, performance and speed, which are serious criteria for the chemical industry.

  11. Application of a passive electrochemical noise technique to localized corrosion of candidate radioactive waste container materials

    SciTech Connect

    Korzan, M.A.

    1994-05-01

    One of the key engineered barriers in the design of the proposed Yucca Mountain repository is the waste canister that encapsulates the spent fuel elements. Current candidate metals for the canisters to be emplaced at Yucca Mountain include cast iron, carbon steel, Incoloy 825 and titanium code-12. This project was designed to evaluate passive electrochemical noise techniques for measuring pitting and corrosion characteristics of candidate materials under prototypical repository conditions. Experimental techniques were also developed and optimized for measurements in a radiation environment. These techniques provide a new method for understanding material response to environmental effects (i.e., gamma radiation, temperature, solution chemistry) through the measurement of electrochemical noise generated during the corrosion of the metal surface. In addition, because of the passive nature of the measurement the technique could offer a means of in-situ monitoring of barrier performance.

  12. Planar multi-electrode array sensor for localized electrochemical corrosion detection

    DOEpatents

    Tormoen, Garth William; Brossia, Christopher Sean

    2014-01-07

    A planarized type of coupled multi-electrode corrosion sensing device. Electrode pads are fabricated on a thin backing, such as a thin film. Each pad has an associated electrical lead for connection to auxiliary electronic circuitry, which may include a resistor associated with each electrical pad. The design permits the device to be easily placed in small crevices or under coatings such as paint.

  13. Demonstration of lithographic patterning in measurements of general and localized corrosion on alloy 22

    SciTech Connect

    Bedrossian, P J; Farmer, J C

    1999-07-01

    We have demonstrated a new technique capable of detecting generalized corrosion of metallographically-polished materials with nanometer-scale precision. After exposing a lithographically-patterned coupon of Alloy 22 to an electrolyte in a potentiostatically-controlled cell for twenty-four hours, we detected the loss of up to 130nm of metal. In addition, ''wormholes'' were detected at certain points of intersection of three grain boundaries.

  14. The influence of sunlight on the localized corrosion of UNS S31600 in natural seawater.

    PubMed

    Eashwar, M; Subramanian, G; Palanichamy, S; Rajagopal, G

    2011-09-01

    Tests were conducted on the performance of UNS S31600 stainless steel (SS) in a natural day/night cycle vs full darkness under conditions of natural marine biofilm accumulation. In quiescent flowing seawater tests in the laboratory as well as under natural immersion in the sea, diffuse sunlight (∼10% of natural) counteracted the influence of marine biofilms and produced substantial inhibition of the corrosion of SS. Thus, the probabilities (percentage attack) and propagation rates (depths of attack) in multiple crevice tests were substantially lower in the day/night cycle than in the dark. A benefit was also observed for welded SS in terms of the time to corrosion initiation and the mass loss. SS in the passive state showed broader passive regions, well-defined breakdown potentials and markedly smaller anodic and cathodic current densities under the diurnal cycle. The overall reduction in corrosion is attributed to a combination of electrochemical photoinhibition and simultaneous photoinactivation of microbially mediated metal redox reactions linked to cathodic kinetics. These data offer fresh insights into the behaviour of SS under practical seawater situations and the proposed potential use of illumination in the mitigation of biologically influenced consequences.

  15. The role of local strains from prior cold work on stress corrosion cracking of α-brass in Mattsson's solution

    SciTech Connect

    Ulaganathan, Jaganathan Newman, Roger C.

    2014-06-01

    The dynamic strain rate ahead of a crack tip formed during stress corrosion cracking (SCC) under a static load is assumed to arise from the crack propagation. The strain surrounding the crack tip would be redistributed as the crack grows, thereby having the effect of dynamic strain. Recently, several studies have shown cold work to cause accelerated crack growth rates during SCC, and the slip-dissolution mechanism has been widely applied to account for this via a supposedly increased crack-tip strain rate in cold worked material. While these interpretations consider cold work as a homogeneous effect, dislocations are generated inhomogeneously within the microstructure during cold work. The presence of grain boundaries results in dislocation pile-ups that cause local strain concentrations. The local strains generated from cold working α-brass by tensile elongation were characterized using electron backscatter diffraction (EBSD). The role of these local strains in SCC was studied by measuring the strain distributions from the same regions of the sample before cold work, after cold work, and after SCC. Though, the cracks did not always initiate or propagate along boundaries with pre-existing local strains from the applied cold work, the local strains surrounding the cracked boundaries had contributions from both the crack propagation and the prior cold work. - Highlights: • Plastic strain localization has a complex relationship with SCC susceptibility. • Surface relief created by cold work creates its own granular strain localization. • Cold work promotes crack growth but several other factors are involved.

  16. Mammalian DNA ligase III: Molecular cloning, chromosomal localization, and expression in spermatocytes undergoing meiotic recombination

    SciTech Connect

    Chen, Jingwen; Danehower, S.; Besterman, J.M.; Husain, I.

    1995-10-01

    Three biochemically distinct DNA ligase activities have been identified in mammalian cell extracts. We have recently purified DNA ligase II and DNA ligase III to near homogeneity from bovine liver and testis tissue, respectively. Amino acid sequencing studies indicated that these enzymes are encoded by the same gene. In the present study, human and murine cDNA clones encoding DNA ligase III were isolated with probes based on the peptide sequences. The human DNA ligase III cDNA encodes a polypeptide of 862 amino acids, whose sequence is more closely related to those of the DNA ligases encoded by poxviruses than to replicative DNA ligases, such as human DNA ligase I. In vitro transcription and translation of the cDNA produced a catalytically active DNA ligase similar in size and substrate specificity to the purified bovine enzyme. The DNA ligase III gene was localized to human chromosome 17, which eliminated this gene as a candidate for the cancer-prone disease Bloom syndrome that is associated with DNA joining abnormalities. DNA ligase III is ubiquitously expressed at low levels, except in the testes, in which the steady-state levels of DNA ligase III mRNA are at least 10-fold higher than those detected in other tissues and cells. Since DNA ligase I mRNA is also present at high levels in the testes, we examined the expression of the DNA ligase genes during spermatogenesis. DNA ligase I mRNA expression correlated with the contribution of proliferating supermatogonia cells to the testes, in agreement with the previously defined role of this enzyme in DNA replications. In contrast, elevated levels of DNA ligase III mRNA were observed in primary supermatocytes undergoing recombination prior to the first meiotic division. Therefore, we suggest that DNA ligase III seals DNA strand breaks that arise during the process of meiotic recombination in germ cells and as a consequence of DNA damage in somatic cells. 62 refs., 7 figs.

  17. Potential for the localized corrosion of alloy 22 Waste Packages in Multiple-Salt Deliquescent Brines in the Yucca Mountain Repository

    SciTech Connect

    King, F.; Arthur, R.; Apted, M.; Kessler, J.H.

    2007-07-01

    It has been postulated that the deliquescence of multiple-salt systems in dust deposits and the consequent localized corrosion in high-temperature brines could lead to premature failure of the Alloy 22 waste packages in the Yucca Mountain repository. EPRI has developed a decision tree approach to determine if the various stages leading to waste package failure are possible and whether the safety of the repository system could be compromised as a result. Through a series of arguments, EPRI has shown that it is highly unlikely that the multiple-salt deliquescent brines will form in the first place and, even if they did, that they would not be thermodynamically stable, that the postulated brines are not corrosive and would not lead to the initiation of localized corrosion of Alloy 22, that even if localized corrosion did initiate that the propagation would stifle and cease long before penetration of the waste package outer barrier, and that even if premature waste package failures did occur from this cause that the safety of the overall system would not be compromised. EPRI concludes, therefore, that the postulated localized corrosion of the waste packages due to high-temperature deliquescent brines is neither a technical nor a safety issue of concern for the Yucca Mountain repository. (authors)

  18. 40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec. 123 III Appendix III to Part 310 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND... Reimbursement to Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec....

  19. 40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec. 123 III Appendix III to Part 310 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND... Reimbursement to Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec....

  20. 40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec. 123 III Appendix III to Part 310 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND... Reimbursement to Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec....

  1. 40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec. 123 III Appendix III to Part 310 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SUPERFUND... Reimbursement to Local Governments for Emergency Response to Hazardous Substance Release Under CERCLA Sec....

  2. Protein kinase A regulates RNA polymerase III transcription through the nuclear localization of Maf1

    PubMed Central

    Moir, Robyn D.; Lee, JaeHoon; Haeusler, Rebecca A.; Desai, Neelam; Engelke, David R.; Willis, Ian M.

    2006-01-01

    Maf1 is an essential and specific mediator of transcriptional repression in the RNA polymerase (pol) III system. Maf1-dependent repression occurs in response to a wide range of conditions, suggesting that the protein itself is targeted by the major nutritional and stress-signaling pathways. We show that Maf1 is a substrate for cAMP-dependent PKA in vitro and is differentially phosphorylated on PKA sites in vivo under normal versus repressing conditions. PKA activity negatively regulates Maf1 function because strains with unregulated high PKA activity block repression of pol III transcription in vivo, and strains lacking all PKA activity are hyperrepressible. Nuclear accumulation of Maf1 is required for transcriptional repression and is regulated by two nuclear localization sequences in the protein. An analysis of PKA phosphosite mutants shows that the localization of Maf1 is affected via the N-terminal nuclear localization sequence. In particular, mutations that prevent phosphorylation at PKA consensus sites promote nuclear accumulation of Maf1 without inducing repression. These results indicate that negative regulation of Maf1 by PKA is achieved by inhibiting its nuclear import and suggest that a PKA-independent activation step is required for nuclear Maf1 to function in the repression of pol III transcription. Finally, we report a previously undescribed phenotype for Maf1 in tRNA gene-mediated silencing of nearby RNA pol II transcription. PMID:17005718

  3. LOCAL LUMINOUS INFRARED GALAXIES. III. CO-EVOLUTION OF BLACK HOLE GROWTH AND STAR FORMATION ACTIVITY?

    SciTech Connect

    Alonso-Herrero, Almudena; Hernan-Caballero, Antonio; Pereira-Santaella, Miguel; Rieke, George H.; Diamond-Stanic, Aleksandar M.; Wang Yiping; Rigopoulou, Dimitra

    2013-03-10

    Local luminous infrared (IR) galaxies (LIRGs) have both high star formation rates (SFR) and a high AGN (Seyfert and AGN/starburst composite) incidence. Therefore, they are ideal candidates to explore the co-evolution of black hole (BH) growth and star formation (SF) activity, not necessarily associated with major mergers. Here, we use Spitzer/IRS spectroscopy of a complete volume-limited sample of local LIRGs (distances of <78 Mpc). We estimate typical BH masses of 3 Multiplication-Sign 10{sup 7} M{sub Sun} using [Ne III] 15.56 {mu}m and optical [O III] {lambda}5007 gas velocity dispersions and literature stellar velocity dispersions. We find that in a large fraction of local LIRGs, the current SFR is taking place not only in the inner nuclear {approx}1.5 kpc region, as estimated from the nuclear 11.3 {mu}m PAH luminosities, but also in the host galaxy. We next use the ratios between the SFRs and BH accretion rates (BHAR) to study whether the SF activity and BH growth are contemporaneous in local LIRGs. On average, local LIRGs have SFR to BHAR ratios higher than those of optically selected Seyferts of similar active galactic nucleus (AGN) luminosities. However, the majority of the IR-bright galaxies in the revised-Shapley-Ames Seyfert sample behave like local LIRGs. Moreover, the AGN incidence tends to be higher in local LIRGs with the lowest SFRs. All of this suggests that in local LIRGs there is a distinct IR-bright star-forming phase taking place prior to the bulk of the current BH growth (i.e., AGN phase). The latter is reflected first as a composite and then as a Seyfert, and later as a non-LIRG optically identified Seyfert nucleus with moderate SF in its host galaxy.

  4. A new approach to study local corrosion processes on steel surfaces by combining different microscopic techniques

    NASA Astrophysics Data System (ADS)

    Heyer, A.; D'Souza, F.; Bruin, A.; Ferrari, G.; Mol, J. M. C.; de Wit, J. H. W.

    2012-09-01

    Corrosion studies of materials on the micro or even nano-scale level are cumbersome due to instrumental limitations and handling procedures. If biological processes are involved the spatial resolution is even more important and sample preparation is usually the limitation. Attachment of bacteria on stainless steel surface is a complex interfacial process including interactions of bacterial cells and bacterial extracellular polymeric substances with the surface. To overcome the limitations in sample preparations and resolution we present a new stainless steel sample holder to switch among epifluorescent microscope (EFM), AFM and SEM at exactly the same position. Exemplary bacterial accumulation was studied by staining the bacterial DNA with a fluorescent dye over time. It was possible to distinguish among bacteria and other surface characteristic such as deformations or grain structures. Also surface topographic features such as roughness at the grain boundaries and deposits were quantified. All three techniques complement one another in the way that AFM is a high-resolution technique that does not allow to distinguish directly bacterial cell structures, whereas EFM offers excellent bacterial identification based on staining at a low resolution that can complement AFM images. Application of SEM in the last step will reveal inclusions and grain structure and combined with EDX gives the composition of the substrate, inclusions and corrosion deposit. The combination of the three high-resolution techniques enables a more detailed understanding of surface phenomena. The method itself is quite elegant and easy to handle which is an important aspect in materials research, especially when a high sample throughput is needed.

  5. Breakpoints in Robertsonian translocations are localized to satellite III DNA by fluorescence in situ hybridization

    SciTech Connect

    Gravholt, C.H.; Friedrich, U.; Caprani, M.; Jorgensen, A.L. )

    1992-12-01

    The authors characterized 21 t(13;14) and 3 t(14;21) Robertsonian translocations for the presence of DNA derived from the short arms of the translocated acrocentric chromosomes and identified their centromeres. Nineteen of these 24 translocation carriers were unrelated. Using centromeric [alpha]-repeat DNA as chromosome-specific probe, they found by in situ hybridization that all 24 translocation chromosomes were dicentric. The chromatin between the two centromeres did not stain with silver, and no hybridization signal was detected with probes for rDNA or [beta]-satellite DNA that flank the distal and proximal ends of the rDNA region on the short arm of the acrocentrics. By contrast, all 24 translocation chromosomes gave a distinct hybridization signal when satellite III DNA was used as probe. This result strongly suggests that the chromosomal rearrangements leading to Robertsonian translocations occur preferentially in satellite III DNA. The authors hypothesize that guanine-rich satellite III repeats may promote chromosomal recombination by formation of tetraplex structures. The findings localize satellite III DNA to the short arm of the acrocentric chromosomes distal to centromeric [alpha]-repeat DNA and proximal to [beta]-satellite DNA. 32 refs., 4 figs., 2 tabs.

  6. Characterization of microstructure, local deformation and microchemistry in Alloy 690 heat-affected zone and stress corrosion cracking in high temperature water

    NASA Astrophysics Data System (ADS)

    Lu, Zhanpeng; Chen, Junjie; Shoji, Tetsuo; Takeda, Yoichi; Yamazaki, Seiya

    2015-10-01

    With increasing the distance from the weld fusion line in an Alloy 690 heat-affected zone, micro-hardness decreases, kernel average misorientation decreases and the fraction of Σ3 boundaries increases. Chromium depletion at grain boundaries in the Alloy 690 heat-affected zone is less significant than that in an Alloy 600 heat-affected zone. Alloy 690 heat-affected zone exhibits much higher IGSCC resistance than Alloy 600 heat-affected zone in simulated pressurized water reactor primary water. Heavily cold worked Alloy 690 exhibits localized intergranular stress corrosion cracking. The effects of metallurgical and mechanical properties on stress corrosion cracking in Alloy 690 are discussed.

  7. Localization of Electronic States in III-V Semiconductor Alloys: A Comparative Study

    NASA Astrophysics Data System (ADS)

    Pashartis, C.; Rubel, O.

    2017-06-01

    Electronic properties of III-V semiconductor alloys are examined using first principles, with the focus on the spatial localization of electronic states. We compare localization at the band edges due to various isovalent impurities in a host GaAs, including its impact on the photoluminescence linewidths and carrier mobilities. The extremity of localization at the band edges is correlated with the ability of individual elements to change the band gap and the relative band alignment. Additionally, the formation energies of substitutional defects are calculated and linked to challenges associated with the growth and formability of alloys. A spectrally resolved inverse participation ratio is used to map localization in prospective GaAs-based materials alloyed with B, N, In, Sb, and Bi for 1.55 -μ m -wavelength telecommunication lasers. This analysis is complemented by a band unfolding of the electronic structure and a discussion of the implications of localization on the optical gain and Auger losses. Correspondence with experimental data on the broadening of the photoluminescence spectrum and charge-carrier mobilities show that the localization characteristics can serve as a guideline for the engineering of semiconductor alloys.

  8. Influence of pH on the localized corrosion of iron

    SciTech Connect

    Webley, R.; Henry, R.

    1986-06-01

    The influence of pH on the pitting corrosion of iron in chloride and sulfate solutions was determined using two artificial pit apparatuses to obtain the pH near the surface of the pit bottom. A glass membrane electrode and an antimony electrode were used to measure pH in the two apparatuses. Using solutions of NaCl and Na/sub 2/SO/sub 4/ at current densities of 0.5, 5.0, and 10 mA/cm/sup 2/ pH's in the range 5 to 6 were obtained with the first apparatus. The antimony probe did not measure pH accurately in solutions of 1 N NaCl and 1 N Na/sub 2/SO/sub 4/ and had an error of approximately 2 pH units. A one-dimensional transport model was developed to predict pH variations around the pit mouth and inside the pit. The validity of this model was not verified due to the relative lack of precision with pH measurement techniques.

  9. Hydroxyapatite microparticles as feedback-active reservoirs of corrosion inhibitors.

    PubMed

    Snihirova, D; Lamaka, S V; Taryba, M; Salak, A N; Kallip, S; Zheludkevich, M L; Ferreira, M G S; Montemor, M F

    2010-11-01

    This work contributes to the development of new feedback-active anticorrosion systems. Inhibitor-doped hydroxyapatite microparticles (HAP) are used as reservoirs, storing corrosion inhibitor to be released on demand. Release of the entrapped inhibitor is triggered by redox reactions associated with the corrosion process. HAP were used as reservoirs for several inhibiting species: cerium(III), lanthanum(III), salicylaldoxime, and 8-hydroxyquinoline. These species are effective corrosion inhibitors for a 2024 aluminum alloy (AA2024), used here as a model metallic substrate. Dissolution of the microparticles and release of the inhibitor are triggered by local acidification resulting from the anodic half-reaction during corrosion of AA2024. Calculated values and experimentally measured local acidification over the aluminum anode (down to pH = 3.65) are presented. The anticorrosion properties of inhibitor-doped HAP were assessed using electrochemical impedance spectroscopy. The microparticles impregnated with the corrosion inhibitors were introduced into a hybrid silica-zirconia sol-gel film, acting as a thin protective coating for AA2024, an alloy used for aeronautical applications. The protective properties of the sol-gel films were improved by the addition of HAP, proving their applicability as submicrometer-sized reservoirs of corrosion inhibitors for active anticorrosion coatings.

  10. The electrochemical behavior of the Al{sub 3}Fe intermetallic compound and localized corrosion of impure 1100 Al

    SciTech Connect

    Buchheit, R.G.; Maestas, L.M.; Sorensen, N.R.

    1993-11-01

    Pitting of 1100 Al(Al-1.0(Fe,Cu,Si)) due to Al{sub 3}Fe constituent particles has been studied by examining a variety of intrinsic, extrinsic, and environmental factors that contribute to localized corrosion. Consistent with results from other studies, Al{sub 3}Fe is noble with respect to its microstructural surroundings and pitting is localized to the particle periphery. Polarization curves indicate that cathodic electron transfer reactions are supported on Al{sub 3}Fe at high rates, however, a anodic electron transfer reactions are not. Interparticle spacing appears to play a strong role in determining where pitting will occur, while Al{sub 3}Fe particle area plays a lesser role. Solution pH, applied potential, and exposure time each have measurable effects on the electrochemical behavior of Al{sub 3}Fe and the {alpha}-Al matrix phase which can impact either the galvanic potential of the Al{sub 3}Fe/{alpha}-Al couple, or charge transfer processes on Al{sub 3}Fe particles.

  11. RNA processing factors Swd2.2 and Sen1 antagonize RNA Pol III-dependent transcription and the localization of condensin at Pol III genes.

    PubMed

    Legros, Pénélope; Malapert, Amélie; Niinuma, Sho; Bernard, Pascal; Vanoosthuyse, Vincent

    2014-11-01

    Condensin-mediated chromosome condensation is essential for genome stability upon cell division. Genetic studies have indicated that the association of condensin with chromatin is intimately linked to gene transcription, but what transcription-associated feature(s) direct(s) the accumulation of condensin remains unclear. Here we show in fission yeast that condensin becomes strikingly enriched at RNA Pol III-transcribed genes when Swd2.2 and Sen1, two factors involved in the transcription process, are simultaneously deleted. Sen1 is an ATP-dependent helicase whose orthologue in Saccharomyces cerevisiae contributes both to terminate transcription of some RNA Pol II transcripts and to antagonize the formation of DNA:RNA hybrids in the genome. Using two independent mapping techniques, we show that DNA:RNA hybrids form in abundance at Pol III-transcribed genes in fission yeast but we demonstrate that they are unlikely to faciliate the recruitment of condensin. Instead, we show that Sen1 forms a stable and abundant complex with RNA Pol III and that Swd2.2 and Sen1 antagonize both the interaction of RNA Pol III with chromatin and RNA Pol III-dependent transcription. When Swd2.2 and Sen1 are lacking, the increased concentration of RNA Pol III and condensin at Pol III-transcribed genes is accompanied by the accumulation of topoisomerase I and II and by local nucleosome depletion, suggesting that Pol III-transcribed genes suffer topological stress. We provide evidence that this topological stress contributes to recruit and/or stabilize condensin at Pol III-transcribed genes in the absence of Swd2.2 and Sen1. Our data challenge the idea that a processive RNA polymerase hinders the binding of condensin and suggest that transcription-associated topological stress could in some circumstances facilitate the association of condensin.

  12. Role of Localized Deformation in Irradiation-Assisted Stress Corrosion Cracking Initiation

    NASA Astrophysics Data System (ADS)

    West, Elaine A.; McMurtrey, Michael D.; Jiao, Zhijie; Was, Gary S.

    2012-01-01

    Intergranular cracking of irradiated austenitic alloys depended on localized grain boundary stress and deformation in both high-temperature aqueous and argon environments. Tensile specimens were irradiated with protons to doses of 1 to 7 dpa and then strained in high-temperature argon, simulated boiling water reactor normal water chemistry, and supercritical water environments. Quantitative measurements confirmed that the initiation of intergranular cracks was promoted by (1) the formation of coarse dislocation channels, (2) discontinuous slip across grain boundaries, (3) a high inclination of the grain boundary to the tensile axis, and (4) low-deformation propensity of grains as characterized by their Schmid and Taylor factors. The first two correlations, as well as the formation of intergranular cracks at the precise locations of dislocation channel-grain boundary intersections are evidence that localized deformation drives crack initiation. The latter two correlations are evidence that intergranular cracking is promoted at grain boundaries experiencing elevated levels of normal stress.

  13. Investigation of the inhibiting action of O-, S- and N-dithiocarbamato(1,4,8,11-tetraazacyclotetradecane)cobalt(III) complexes on the corrosion of iron in HClO 4 acid

    NASA Astrophysics Data System (ADS)

    Babić-Samardžija, K.; Khaled, K. F.; Hackerman, N.

    2005-02-01

    The inhibiting properties of four macrocyclic cobalt(III) complexes of the general formula [Co III(Rdtc)cyclam](ClO 4) 2, where cyclam and Rdtc- refer to 1,4,8,11-tetraazacyclotetradecane and morpholine-, thiomorpholine-, piperazine-, N-methylpiperazine-dithiocarbamates, respectively, has been studied on the corrosion of iron in aerated 0.1 M HClO 4 solutions by potentiodynamic polarization (dc) technique and electrochemical impedance spectroscopy (ac). Inhibitor efficiency for the corrosion of iron is found to be better for cobalt complexes then for related amino-ligands. The impedance increases with inhibitor concentration. Polarization curves indicate that the inhibitors are predominantly mixed-type. Better protection by the complex inhibitors was obtained with longer immersion time. The best fit for inhibitors adsorption is obtained using the Langmuir isotherm model. Molecular modeling calculations were used to correlate structural properties of the complex species and their inhibition efficiency.

  14. Shadow corrosion

    NASA Astrophysics Data System (ADS)

    Ramasubramanian, N.

    2004-07-01

    An electrochemical mechanism, based on energetically favored complimentary reduction and oxidation reactions, operating in conjunction with radiolysis is proposed for explaining the shadow corrosion phenomenon observed under BWR conditions. The electrochemical reaction on platinum and nickel alloys (Inconel and X-750) is the oxidation of H 2O 2 to produce a localized enhancement in the concentrations of HO 2 and O 2. Energy level of the conduction band of ZrO 2 matches well with that for the reduction of HO 2 and O 2 regenerating H 2O 2. This reduction of the powerful oxidants, stimulates electron emission in ZrO 2 which then is balanced by increased oxidation of zirconium to generate additional electrons and hence also anion vacancies. A coupling between Zircaloy and platinum or nickel alloy is provided by H + transport, the source for initiating shadow corrosion, to Zircaloy-2 (Zircaloy-2 negative relative to platinum or the nickel alloy) in the gap between the materials. An enhanced localized corrosion of Zircaloy-2 occurs, its incidence dependent upon the transport of HO 2, O 2, H + and H 2O 2 in the coolant in the gap.

  15. 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.

  16. The unlikelihood of localized corrosion of nuclear waste packages arising from deliquescent brine formation

    NASA Astrophysics Data System (ADS)

    Apted, M.; Arthur, R.; King, F.; Langmuir, D.; Kessler, J.

    2005-01-01

    The Nuclear Waste Technical Review Board (NWTRB) recently postulated a scenario for the formation of a deliquescent, divalent-cation (Ca, Mg) chloride brine from wind-blown dust on the surface of an alloy 22 container designed to hold radioactive waste. The NWTRB suggested that such brines could lead to localized penetrations of waste packages at a proposed repository in Yucca Mountain, Nevada. In response, the Electric Power Research Institute (EPRI) sponsored an independent analysis, specifically examining and responding to a series of decision points in the NWTRB’s scenario. Only if all of these questions could be answered affirmatively would NWTRB’s scenario result in potential noncompliance with regulatory criteria. The EPRI analysis found that none of the questions has an affirmative answer.

  17. SECM Study of Effect of Chromium Content on the Localized Corrosion Behavior of Low-Alloy Steels in Chloride Environment

    NASA Astrophysics Data System (ADS)

    Indira, K.; Nishimura, T.

    2016-10-01

    This paper investigates the effect of chromium (Cr) content (0, 1, 3 and 5% Cr) in epoxy-coated alloy steel against corrosion using in situ electrochemical techniques such as EIS and SECM in a 3% NaCl solution. The EIS results revealed that the epoxy-coated Cr steel exhibited higher impedance values than carbon steel, which is attributed to the greater resistance of Cr steel toward corrosion. Based on the cyclic voltammogram results, the tip potentials were set at -0.7, 0.04 and 0.60 V for determining the concentration of dissolved oxygen at cathodic region, and oxidation of Cr2+ and Fe2+ at anodic region, respectively. The SECM measurements showed that, the tip current in the anodic region has decreased with increase in Cr content of the sample, which indicates that the oxidation of Fe2+ and Cr2+ decreases (corrosion is reduced) with the increase in Cr content of the steel. Besides, 5% Cr steel can maintain the highest corrosion resistance, and 1 and 3% Cr steels have higher corrosion resistance than the 0% Cr steel. This higher corrosion resistance of Cr steel samples could be due to the formation of Cr-rich hydro-oxide layers [Cr(OH)3 as a corrosion product] on the surface of the samples. Thus, the epoxy-coated Cr alloy steel has greater corrosion resistance in a chloride-containing environment than the carbon steel. Hence, epoxy-coated Cr alloy steel can be successfully used as a construction material in structures.

  18. Alloy 22 Localized Corrosion Susceptibility In Aqueous Solutions Of Chloride And Nitrate Salts Of Sodium And Potassium At 110 - 150?C

    SciTech Connect

    Felker, S; Hailey, P D; Lian, T; Staggs, K J; Gdowski, G E

    2006-01-17

    Alloy 22 (a nickel-chromium-molybdenum-tungsten alloy) is being investigated for use as the outer barrier of waste containers for a high-level nuclear waste repository in the thick unsaturated zone at Yucca Mountain, Nevada. Experiments were conducted to assess crevice corrosion of Alloy 22 in de-aerated aqueous solutions of chloride and nitrate salts of potassium and sodium in the temperature range 110-150 C (some limited testing was also conducted at 90 C). Electrochemical tests were run in neutral salt solutions without acid addition and others were run in salt solutions with an initial hydrogen ion concentration of 10{sup -4} molal. The Alloy 22 specimens were weld prism specimens and de-aeration was performed with nitrogen gas. No evidence of crevice corrosion was observed in the range 125-150 C. In the 120 to 160 C temperature range, the anionic concentration of stable aqueous solutions is dominated by nitrate relative to chloride. At nominally 120 C, the minimum nitrate to chloride ratio is about 4.5, and it increases to about 22 at nominally 155 C. The absence of localized corrosion susceptibility in these solutions is attributed to the known inhibiting effect of the nitrate anion. At 110 C, aqueous solutions can have dissolved chloride in excess of nitrate. Localized corrosion was observed at nitrate to chloride ratios up to 1.0, the highest ratio tested. The extent of localized corrosion was confined to the crevice region of the samples, and was limited for nitrate to chloride ratios greater than or equal to 0.3. Aqueous solution chemistry studies indicate that nitrate to chloride ratios of less than 0.5 are possible for temperatures up to nominally 116 C. However, the exact upper temperature limit is unknown and no electrochemical testing was done at these temperatures. Limited comparison between 8 m Cl aqueous solutions of Na + K on the one hand and Ca on the other indicated similar electrochemical E{sub crit} values and similar morphology of attack

  19. Effect of Organic Acid Additions on the General and Localized Corrosion Susceptibility of Alloy 22 in Chloride Solutions

    SciTech Connect

    Carranza, R M; Giordano, C M; Rodr?guez, M A; Ilevbare, G O; Rebak, R B

    2007-08-28

    Electrochemical studies such as cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 (N06022) in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. All the tested material was wrought Mill Annealed (MA). Tests were also performed in NaCl solutions containing weak organic acids such as oxalic, acetic, citric and picric. Results show that the corrosion rate of Alloy 22 was significantly higher in solutions containing oxalic acid than in solutions of pure NaCl at the same pH. Citric and picric acids showed a slightly higher corrosion rate, and acetic acid maintained the corrosion rate of pure chloride solutions at the same pH. Organic acids revealed to be weak inhibitors for crevice corrosion. Higher concentration ratios, compared to nitrate ions, were needed to completely inhibit crevice corrosion in chloride solutions. Results are discussed considering acid dissociation constants, buffer capacity and complex formation constants of the different weak acids.

  20. Effect of microstructure and chemical composition on localized corrosion resistance of a AISI 304L stainless steel after nanopulsed-laser surface melting

    NASA Astrophysics Data System (ADS)

    Pacquentin, W.; Caron, N.; Oltra, R.

    2015-11-01

    Changes induced in the surface properties of AISI 304L stainless steel when it is treated with a nanopulsed ytterbium-doped fiber laser were investigated to determine the microscale distribution of its physico-chemical properties. A Gaussian energy distribution was created with a radius of 71 μm (1/e2) at the focal point. Local investigations were carried out using transmission electron microscopy to consider the effect of overlapping individual laser impacts. The results obtained reveal that laser surface melting leads to changes in the crystallographic structure of the steel through the formation of a δ-ferritic phase. It also results in the creation of an oxide layer that increases the corrosion resistance of the steel, with the chemical composition, structure and thickness of this layer being dependent on the overlap percentage and the position along the beam radius. Measurement of the localized corrosion resistance in a 30 g L-1 NaCl solution using polarization curves found that optimal laser treatment conditions can led to an increase in the breakdown potential of more than 500 mV, which corresponds to a significant improvement in corrosion resistance.

  1. Diagnosis and Management of Adverse Local Tissue Reactions Secondary to Corrosion at the Head-Neck Junction in Patients With Metal on Polyethylene Bearings.

    PubMed

    Plummer, Darren R; Berger, Richard A; Paprosky, Wayne G; Sporer, Scott M; Jacobs, Joshua J; Della Valle, Craig J

    2016-01-01

    We reviewed 27 patients who underwent revision for an adverse local tissue reaction (ALTR) secondary to corrosion at the head-neck junction with MoP bearings. Serum cobalt and chromium levels were elevated in all cases, with a mean cobalt of 11.2 ppb and chromium of 2.2 ppb. Patients underwent modular bearing exchange, including a ceramic head with a titanium sleeve in 23 of 27 cases with only one recurrence of ALTR in one of the four patients not treated with a ceramic head. The diagnosis of ALTR secondary to corrosion is associated with cobalt levels of >1 ppb with cobalt levels elevated above chromium. Retention of a well-fixed stem and modular exchange to a ceramic head leads to resolution of symptoms and decreases in metal levels. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Oxidation of sulfoxides and arsenic(III) in corrosion of nanoscale zero valent iron by oxygen: evidence against ferryl ions (Fe(IV)) as active intermediates in Fenton reaction.

    PubMed

    Pang, Su-Yan; Jiang, Jin; Ma, Jun

    2011-01-01

    Previous studies have shown that the corrosion of zerovalent iron (ZVI) by oxygen (O(2)) via the Fenton reaction can lead to the oxidation of various organic and inorganic compounds. However, the nature of the oxidants involved (i.e., ferryl ion (Fe(IV)) versus hydroxyl radical (HO(•))) is still a controversial issue. In this work, we reevaluated the relative importance of these oxidants and their role in As(III) oxidation during the corrosion of nanoscale ZVI (nZVI) in air-saturated water. It was shown that Fe(IV) species could react with sulfoxides (e.g., dimethyl sulfoxide, methyl phenyl sulfoxide, and methyl p-tolyl sulfoxide) through a 2-electron transfer step producing corresponding sulfones, which markedly differed from their HO(•)-involved products. When using these sulfoxides as probe compounds, the formation of oxidation products indicative of HO(•) but no generation of sulfone products supporting Fe(IV) participation were observed in the nZVI/O(2) system over a wide pH range. As(III) could be completely or partially oxidized by nZVI in air-saturated water. Addition of scavengers for solution-phase HO(•) and/or Fe(IV) quenched As(III) oxidation at acidic pH but had little effect as solution pH increased, highlighting the importance of the heterogeneous iron surface reactions for As(III) oxidation at circumneutral pH.

  3. Corrosion cracking

    SciTech Connect

    Goel, V.S.

    1985-01-01

    This book presents the papers given at a conference on alloy corrosion cracking. Topics considered at the conference included the effect of niobium addition on intergranular stress corrosion cracking, corrosion-fatigue cracking in fossil-fueled-boilers, fracture toughness, fracture modes, hydrogen-induced thresholds, electrochemical and hydrogen permeation studies, the effect of seawater on fatigue crack propagation of wells for offshore structures, the corrosion fatigue of carbon steels in seawater, and stress corrosion cracking and the mechanical strength of alloy 600.

  4. Localized corrosion of 316L stainless steel in tritiated water containing aggressive radiolytic and decomposition products at different temperatures

    NASA Astrophysics Data System (ADS)

    Bellanger, G.

    2008-02-01

    Tritium is one of the more important radionuclides used in nuclear industry as plutonium and uranium. The tritium in tritiated water always causes difficulties in nuclear installations, including equipment corrosion. Moreover, with tritiated water there are, in addition, the radiolytic and decomposition products such as hydrogen peroxide formed during decay, chloride ions produced by degradation of organic seals and oils used for tightness and pumping, and acid pH produced by excitation of nitrogen in air by the β - particle. Highly concentrated tritiated water releases energy and its temperature is about 80 °C, moreover heating is necessary in the tritium processes. These conditions highly facilitate the corrosion of stainless steels by pitting and crevice attack. Corrosion tests were performed by electrochemical analysis methods and by visual inspection of the surface of stainless steel.

  5. The effect of the local chemical composition of grain boundaries on the corrosion resistance of a titanium alloy

    NASA Astrophysics Data System (ADS)

    Chuvil'deev, V. N.; Kopylov, V. I.; Nokhrin, A. V.; Bakhmet'ev, A. M.; Sandler, N. G.; Tryaev, P. V.; Kozlova, N. A.; Tabachkova, N. Yu.; Mikhailov, A. S.; Chegurov, M. K.; Smirnova, E. S.

    2017-01-01

    The influence of the structural-phase state of grain boundaries in a Ti4Al2V (commercial PT3V grade) pseudo-alpha-titanium alloy on its susceptibility to hot-salt intergranular corrosion (IGC) has been studied. It is established that IGC-tested alloy samples exhibit corrosion-induced defects of two types. More extended defects of the first type occur at the V-rich boundaries of coarse grains, while short defects of the second type reside at the grain boundaries with composition close to that of the grain body. The existence of the two types of IGC defects is explained by the classical theory of galvanic microcouples (microcells), according to which the IGC intensity is proportional to the difference of corrosion-active impurity concentrations between the grain boundary and body.

  6. LOCALIZATION OF A TYPE III RADIO BURST OBSERVED BY THE STEREO SPACECRAFT

    SciTech Connect

    Thejappa, G.; MacDowall, R. J. E-mail: Robert.MacDowall@nasa.go

    2010-09-10

    Ray tracing calculations show that (1) emissions from a localized source escape as direct and reflected waves along different paths, (2) the reflected waves experience higher attenuation and group delay because they travel longer path lengths in regions of reduced refractive index, and (3) widely separated spacecraft 'A' and 'B' can detect the direct as well as reflected emissions escaping along different directions. It is proposed that the source of a radio burst observed by twin spacecraft 'A' and 'B' can be localized if at a given frequency the emission at one of them is identified as the direct emission and is identified at the other as the reflected emission by comparing the observed time delays {Delta}T, as well as intensity ratios I{sub B} /I{sub A} with the corresponding values of the direct and reflected emissions obtained for a given coronal model. A type III event observed by the STEREO spacecraft 'A' and 'B' shows that its characteristics are consistent with direct and reflected emissions by being less intense and delayed at 'A' in comparison to that at 'B'. By applying the proposed technique to this event, the location of its source is found to lie between the turning point of the ray and the harmonic layer corresponding to f {sub pe} = f/2, where f and f {sub pe} are the frequency of the emission and the electron plasma frequency, respectively. The comparisons of the widths of the fundamental and harmonic emission cones with the angular separation of spacecraft 'A' and 'B' indicate that the mode of the observed emission is probably the harmonic.

  7. A cautionary note on graphene anti-corrosion coatings

    NASA Astrophysics Data System (ADS)

    Cui, Chenlong; Lim, Alane Tarianna O.; Huang, Jiaxing

    2017-09-01

    Despite graphene's apparent potential for anti-corrosion coatings, it is cathodic to most metals and can promote corrosion at exposed graphene-metal interfaces. This may accelerate dangerous localized corrosion that can seriously weaken the coated metals.

  8. Development of a decision support system for the introduction of alternative methods into local irritancy/corrosivity testing strategies. Creation of fundamental rules for a decision support system.

    PubMed

    Gerner, I; Zinke, S; Graetschel, G; Schlede, E

    2000-01-01

    The notification procedure of the European Union (EU) for new chemicals requires the application of protocols on physicochemical and toxicological tests for the evaluation of physicochemical properties and probable toxic effects of each notified substance. A computerised database was developed from data sets and toxicological test protocols relating to substance properties responsible for skin and eye irritation/corrosion. To develop specific structure-activity relationship (SAR) models and to find rules for a decision support system (DSS) to predict local irritation/corrosion, physical property data, chemical structure data and toxicological data for approximately 1300 chemicals, each having a purity of 95% or more, were evaluated. The evaluation demonstrated that the lipid solubility and aqueous solubility of a chemical are relevant to, or - in some cases - responsible for, the observed local effects of a substance on the skins and eyes of rabbits. The octanol/water partition coefficient and the measured value of the surface tension of a saturated aqueous solution of the substance give additional information that permits the definition of detailed SAR algorithms that use measured solubility values. Data on melting points and vapour pressure can be used to assess the intensity and duration of local contact with a chemical. Considerations relating to the reactivity of a pure chemical can be based on molecular weight and the nature of the heteroatoms present. With respect to local lesions produced following contact with the skin and eyes of rabbits, the data evaluation revealed that no general "local irritation/corrosion potential" of a chemical can be defined. A variety of mechanisms are responsible for the formation of local lesions on the skin or in the eyes: serious lesions are produced by mechanisms different from those that cause moderate irritation in these organs. In order to develop a DSS that uses the information extracted from the database, chemical main

  9. Concrete cover cracking with reinforcement corrosion of RC beam during chloride-induced corrosion process

    SciTech Connect

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2010-03-15

    This paper deals with the evolution of the corrosion pattern based on two beams corroded by 14 years (beam B1CL1) and 23 years (beam B2CL1) of conservation in a chloride environment. The experimental results indicate that, at the cracking initiation stage and the first stage of cracking propagation, localized corrosion due to chloride ingress is the predominant corrosion pattern and pitting corrosion is the main factor that influences the cracking process. As corrosion cracking increases, general corrosion develops rapidly and gradually becomes predominant in the second stage of cracking propagation. A comparison between existing models and experimental results illustrates that, although Vidal et al.'s model can better predict the reinforcement corrosion of beam B1CL1 under localized corrosion, it cannot predict the corrosion of beam B2CL1 under general corrosion. Also, Rodriguez's model, derived from the general corrosion due to electrically accelerated corrosion experiments, cannot match natural chloride corrosion irrespective of whether corrosion is localized or general. Thus, for natural general corrosion in the second stage of cracking propagation, a new model based on the parameter of average steel cross-section loss is put forward to predict steel corrosion from corrosion cracking.

  10. Radiolytic corrosion of uranium dioxide induced by He2+ localized irradiation of water: Role of the produced H2O2 distance

    NASA Astrophysics Data System (ADS)

    Traboulsi, Ali; Vandenborre, Johan; Blain, Guillaume; Humbert, Bernard; Haddad, Ferid; Fattahi, Massoud

    2015-12-01

    The short-range (few μm in water) of the α-emitting from the spent fuel involves that the radiolytic corrosion of this kind of sample occurs at the solid/solution interface. In order to establish the role of localization of H2O2 species produced by the He2+ particle beam in water from the surface, we perform UO2 radiolytic corrosion experiment with different distance between H2O2 production area and UO2 surface. Then, in this work, the radiolytic corrosion of UO2 particles by oxidative species produced by 4He2+ radiolysis of water was investigated in open to air atmosphere. The dose rate, the localization of H2O2 produced by water radiolysis and the grain boundaries present on the surface of the particles were investigated. UO2 corrosion was investigated by in situ (during irradiation) characterization of the solid surface, analysis of H2O2 produced by water radiolysis and quantification of the uranium species released into the solution during irradiation. Characterization of the UO2 particles, surface and volume, was realized by Raman spectroscopy. UV-vis spectrophotometry was used to monitor H2O2 produced by water radiolysis and in parallel the soluble uranium species released into the solution were quantified by inductively coupled plasma mass spectrometry. During the He2+ irradiation of ultra-pure water in contact with the UO2 particles, metastudtite phase was formed on the solid surface indicating an oxidation process of the particles by the oxidative species produced by water radiolysis. This oxidation occurred essentially on the grain boundaries and was accompanied by migration of soluble uranium species (U(VI)) into the irradiated solution. Closer to the surface the localization of H2O2 formation, higher the UO2 oxidation process occurs, whereas the dose rate had no effect on it. Simultaneously, closer to the surface the localization of H2O2 formation lower the H2O2 concentration measured in solution. Moreover, the metastudtite was the only secondary

  11. Evolution of the Corrosion Morphology on AZ31B Tracked Electrochemically and by In Situ Microscopy in Chloride-Containing Media

    NASA Astrophysics Data System (ADS)

    Melia, M. A.; Cain, T. W.; Briglia, B. F.; Scully, J. R.; Fitz-Gerald, J. M.

    2017-06-01

    The evolution of open-circuit corrosion morphology as a function of immersion time for Mg alloy AZ31B in 0.6-M NaCl solution was investigated. Real-time optical microscopy accompanied by simultaneous electrochemical characterization was used to characterize the filiform corrosion (FFC) of AZ31B. Specifically, the behavior of propagating corrosion filaments on the metal surface was observed, and correlations among polarization resistance, filament propagation rates, open-circuit potential, and active coverage of local corrosion sites were revealed. Three distinct stages of corrosion were observed in 0.6-M NaCl. An initial passive region, during which a slow potential rise occurred (termed stage I), a second FFC region (termed stage II) with shallow penetrating, distinct filaments, and a final FFC region (termed stage III) with deeper penetrating filaments, aligned to form a linear front. The electrochemical properties of each stage are discussed, providing insights into the penetration rates and corrosion model.

  12. Adverse Local Tissue Reaction Arising from Corrosion at the Femoral Neck-Body Junction in a Dual-Taper Stem with a Cobalt-Chromium Modular Neck

    PubMed Central

    Cooper, H. John; Urban, Robert M.; Wixson, Richard L.; Meneghini, R. Michael; Jacobs, Joshua J.

    2013-01-01

    Background: Femoral stems with dual-taper modularity were introduced to allow additional options for hip-center restoration independent of femoral fixation in total hip arthroplasty. Despite the increasing availability and use of these femoral stems, concerns exist about potential complications arising from the modular neck-body junction. Methods: This was a multicenter retrospective case series of twelve hips (eleven patients) with adverse local tissue reactions secondary to corrosion at the modular neck-body junction. The cohort included eight women and three men who together had an average age of 60.1 years (range, forty-three to seventy-seven years); all hips were implanted with a titanium-alloy stem and cobalt-chromium-alloy neck. Patients presented with new-onset and increasing pain at a mean of 7.9 months (range, five to thirteen months) following total hip arthroplasty. After serum metal-ion studies and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) revealed abnormal results, the patients underwent hip revision at a mean of 15.2 months (range, ten to twenty-three months). Tissue specimens were examined by a single histopathologist, and the retrieved implants were studied with use of light and scanning electron microscopy. Results: Serum metal levels demonstrated greater elevation of cobalt (mean, 6.0 ng/mL) than chromium (mean, 0.6 ng/mL) or titanium (mean, 3.4 ng/mL). MRI with use of MARS demonstrated adverse tissue reactions in eight of nine patients in which it was performed. All hips showed large soft-tissue masses and surrounding tissue damage with visible corrosion at the modular femoral neck-body junction. Available histology demonstrated large areas of tissue necrosis in seven of ten cases, while remaining viable capsular tissue showed a dense lymphocytic infiltrate. Microscopic analysis was consistent with fretting and crevice corrosion at the modular neck-body interface. Conclusions: Corrosion at the modular neck

  13. Adverse local tissue reaction arising from corrosion at the femoral neck-body junction in a dual-taper stem with a cobalt-chromium modular neck.

    PubMed

    Cooper, H John; Urban, Robert M; Wixson, Richard L; Meneghini, R Michael; Jacobs, Joshua J

    2013-05-15

    Femoral stems with dual-taper modularity were introduced to allow additional options for hip-center restoration independent of femoral fixation in total hip arthroplasty. Despite the increasing availability and use of these femoral stems, concerns exist about potential complications arising from the modular neck-body junction. This was a multicenter retrospective case series of twelve hips (eleven patients) with adverse local tissue reactions secondary to corrosion at the modular neck-body junction. The cohort included eight women and three men who together had an average age of 60.1 years (range, forty-three to seventy-seven years); all hips were implanted with a titanium-alloy stem and cobalt-chromium-alloy neck. Patients presented with new-onset and increasing pain at a mean of 7.9 months (range, five to thirteen months) following total hip arthroplasty. After serum metal-ion studies and metal artifact reduction sequence (MARS) magnetic resonance imaging (MRI) revealed abnormal results, the patients underwent hip revision at a mean of 15.2 months (range, ten to twenty-three months). Tissue specimens were examined by a single histopathologist, and the retrieved implants were studied with use of light and scanning electron microscopy. Serum metal levels demonstrated greater elevation of cobalt (mean, 6.0 ng/mL) than chromium (mean, 0.6 ng/mL) or titanium (mean, 3.4 ng/mL). MRI with use of MARS demonstrated adverse tissue reactions in eight of nine patients in which it was performed. All hips showed large soft-tissue masses and surrounding tissue damage with visible corrosion at the modular femoral neck-body junction. Available histology demonstrated large areas of tissue necrosis in seven of ten cases, while remaining viable capsular tissue showed a dense lymphocytic infiltrate. Microscopic analysis was consistent with fretting and crevice corrosion at the modular neck-body interface. Corrosion at the modular neck-body junction in dual-tapered stems with a modular

  14. Adverse local tissue reactions in metal-on-polyethylene total hip arthroplasty due to trunnion corrosion: the risk of misdiagnosis.

    PubMed

    Whitehouse, M R; Endo, M; Zachara, S; Nielsen, T O; Greidanus, N V; Masri, B A; Garbuz, D S; Duncan, C P

    2015-08-01

    Adverse reaction to wear and corrosion debris is a cause for concern in total hip arthroplasty (THA). Modular junctions are a potential source of such wear products and are associated with secondary pseudotumour formation. We present a consecutive series of 17 patients treated at our unit for this complication following metal-on-highly cross-linked polyethylene (MoP) THA. We emphasise the risk of misdiagnosis as infection, and present the aggregate laboratory results and pathological findings in this series. The clinical presentation was pain, swelling or instability. Solid, cystic and mixed soft-tissue lesions were noted on imaging and confirmed intra-operatively. Corrosion at the head-neck junction was noted in all cases. No bacteria were isolated on multiple pre- and intra-operative samples yet the mean erythrocyte sedimentation rate was 49 (9 to 100) and C-reactive protein 32 (0.6 to 106) and stromal polymorphonuclear cell counts were noted in nine cases. Adverse soft-tissue reactions can occur in MoP THA owing to corrosion products released from the head-neck junction. The diagnosis should be carefully considered when investigating pain after THA. This may avoid the misdiagnosis of periprosthetic infection with an unidentified organism and mitigate the unnecessary management of these cases with complete single- or two-stage exchange. ©2015 The British Editorial Society of Bone & Joint Surgery.

  15. Wave III of brain-stem auditory evoked potentials analysed both with 3-channel Lissajous' trajectory and dipole localization method.

    PubMed

    Paquereau, J; Ingrand, P; Marillaud, A

    1991-01-01

    Wave III of the BAEP was analysed both with 3-channel Lissajous' trajectory (3-CLT) and a dipole localization method. The experiments were performed on 5 normally hearing subjects. The dipole analysis used an iterative algorithm assuming a spherical head model and homogeneous media. 3-CLT planar analysis was performed with a laboratory system. The parameters of plane C (azimuth and elevation) corresponding to wave III and those of the equivalent dipole showed a similar orientation of the plane and the dipole. This result is in agreement with previous investigations and confirms the interest of 3-CLT in far-field analysis and, at the same time, validates the dipole localization model used in this study, at least for BAEP analysis.

  16. General Corrosion and Passive Film Stability

    SciTech Connect

    Dixit, S; Roberts, S; Evans, K; Wolery, T; Carroll, S

    2005-11-29

    We have studied Alloy 22 corrosion and passive film stability in nitrogen-purged Na-K-Cl-NO{sub 3} brines having NO{sub 3}:Cl ratios of 7.4 at 160 C and NO{sub 3}:Cl ratios of 0.5 and 7.4 at 220 C in autoclave experiments under a slight pressure. The experiments were done to show the effect of high nitrate brines on the durability of the Alloy 22 outer barrier of the waste canisters. Ratios of NO{sub 3}:Cl used in this study were lower than expected ratios for the repository environment at these temperatures and atmospheric pressures (NO{sub 3}:Cl > 25), however they were thought to be high enough to inhibit localized corrosion. Localized corrosion occurred on the liquid-immersed and vapor-exposed creviced specimens under all conditions studied. Crevice penetration depths were difficult to quantify due to the effects of deformation and surface deposits. Further characterization is needed to evaluate the extent of localized corrosion. The bulk of the surface precipitates were derived from the partial dissolution of ceramic crevice formers used in the study. At this time we do not know if the observed localized corrosion reflects the corrosiveness of Na-K-Cl-NO{sub 3} solutions at elevated temperature over nine months or if it was an artifact of the experimental protocol. Nor do we know if much more concentrated brines with higher NO{sub 3}:Cl ratios formed by dust deliquescence will initiate localized corrosion on Alloy 22 at 160 and 220 C. Our results are consistent with the conclusion that nitrate concentrations greater than 18.5 molal may be required to offset localized corrosion of Alloy 22 at 160 and 220 C. Stability of the passive film and general corrosion were evaluated on the liquid-immersed and vapor-exposed non-creviced specimens. Elemental depth profiles of the vapor-exposed specimens are consistent with the development of a protective Cr-rich oxide near the base metal. The combined passive film and alloy oxide of the immersed specimens was much thicker

  17. Local Control and Toxicity of a Simultaneous Integrated Boost for Dose Escalation in Locally Advanced Esophageal Cancer: Interim Results from a Prospective Phase I/II Trial.

    PubMed

    Welsh, James W; Seyedin, Steven N; Allen, Pamela K; Hofstetter, Wayne L; Ajani, Jaffer A; Chang, Joe Y; Gomez, Daniel R; Amini, Arya; Swisher, Stephen G; Blum, Mariela A; Younes, Ahmed I; Nguyen, Quynh-Nhu; Minsky, Bruce D; Erasmus, Jeremy J; Lee, Jeffrey H; Bhutani, Manoop; Komaki, Ritsuko U

    2017-02-01

    Approximately 50% of recurrences after standard-dose chemoradiation for locally advanced esophageal cancer occur within the gross tumor volume (GTV). In this prospective phase I/II clinical trial, we explored the use of a simultaneous integrated boost (SIB) dose to the GTV. Forty-four patients with unresectable esophageal cancer received chemoradiation with an SIB of 58.8 to 63 Gy to the GTV and 50.4 Gy to the planning target volume, all in 28 fractions, with 5 weeks of concurrent docetaxel and fluorouracil or capecitabine. The end points were maximum tolerated dose, time to local failure, and clinical response. Excluding those with less than 6 months of follow-up, 38 patients were evaluated at the time of analysis. The median age was 65 years (range 37-84). Most patients (71%) were men; 84% had T3 disease, 37% had N1 disease, 26% had N2 disease, 13% had M1 disease, and 50% had adenocarcinoma. The maximum tolerated SIB dose was 63 Gy. None experienced Common Terminology Criteria for Adverse Events grade 4 or 5 toxicity. At a median follow-up time of 13.3 months (range 1.2-36.2), 11 (29%) had local failure (median time to local failure 2.5 months [range 1.5-23.9]). A comparison with 97 similar patients who received 50.4 Gy without an SIB showed that the SIB reduced the local failure rate for patients with node-positive disease (13% versus 56%, p = 0.04), adenocarcinoma (26% versus 59%, p = 0.02), or stage III-IV disease (29% versus 55%, p = 0.04). SIB intensity-modulated radiation therapy to gross primary disease may improve local control for patients with unresectable locally advanced esophageal cancer, especially those with adenocarcinoma. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

  18. 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.

  19. DEPOSITION TANK CORROSION TESTING FOR ENHANCED CHEMICAL CLEANING POST OXALIC ACID DESTRUCTION

    SciTech Connect

    Mickalonis, J.

    2011-08-29

    An Enhanced Chemical Cleaning (ECC) process is being developed to aid in the high level waste tank closure at the Savannah River Site. The ECC process uses an advanced oxidation process (AOP) to destroy the oxalic acid that is used to remove residual sludge from a waste tank prior to closure. The AOP process treats the dissolved sludge with ozone to decompose the oxalic acid through reactions with hydroxyl radicals. The effluent from this oxalic acid decomposition is to be sent to a Type III waste tank and may be corrosive to these tanks. As part of the hazardous simulant testing that was conducted at the ECC vendor location, corrosion testing was conducted to determine the general corrosion rate for the deposition tank and to assess the susceptibility to localized corrosion, especially pitting. Both of these factors impact the calculation of hydrogen gas generation and the structural integrity of the tanks, which are considered safety class functions. The testing consisted of immersion and electrochemical testing of A537 carbon steel, the material of construction of Type III tanks, and 304L stainless steel, the material of construction for transfer piping. Tests were conducted in solutions removed from the destruction loop of the prototype ECC set up. Hazardous simulants, which were manufactured at SRNL, were used as representative sludges for F-area and H-area waste tanks. Oxalic acid concentrations of 1 and 2.5% were used to dissolve the sludge as a feed to the ECC process. Test solutions included the uninhibited effluent, as well as the effluent treated for corrosion control. The corrosion control options included mixing with an inhibited supernate and the addition of hydroxide. Evaporation of the uninhibited effluent was also tested since it may have a positive impact on reducing corrosion. All corrosion testing was conducted at 50 C. The uninhibited effluent was found to increase the corrosion rate by an order of magnitude from less than 1 mil per year (mpy

  20. Automation of a Local Table of Contents Service Using dBase III.

    ERIC Educational Resources Information Center

    Bellamy, Lois M.; Guyton, Joanne

    1987-01-01

    Automation of a table of contents service at the Methodist Hospital School of Nursing Library using dBase III facilitates matching patrons with journals. The program is also used for journal check-in and mailing labels. Future applications may include production of a journal holdings list, statistics, and reporting. (21 references) (MES)

  1. Automation of a Local Table of Contents Service Using dBase III.

    ERIC Educational Resources Information Center

    Bellamy, Lois M.; Guyton, Joanne

    1987-01-01

    Automation of a table of contents service at the Methodist Hospital School of Nursing Library using dBase III facilitates matching patrons with journals. The program is also used for journal check-in and mailing labels. Future applications may include production of a journal holdings list, statistics, and reporting. (21 references) (MES)

  2. Dependence of the Ce(iii)/Ce(iv) ratio on intracellular localization in ceria nanoparticles internalized by human cells.

    PubMed

    Ferraro, Daniela; Tredici, Ilenia G; Ghigna, Paolo; Castillio-Michel, Hiram; Falqui, Andrea; Di Benedetto, Cristiano; Alberti, Giancarla; Ricci, Vittorio; Anselmi-Tamburini, Umberto; Sommi, Patrizia

    2017-01-26

    CeO2 nanoparticles (CNPs) have been investigated as promising antioxidant agents with significant activity in the therapy of diseases involving free radicals or oxidative stress. However, the exact mechanism responsible for CNP activity has not been completely elucidated. In particular, in situ evidence of modification of the oxidative state of CNPs in human cells and their evolution during cell internalization and subsequent intracellular distribution has never been presented. In this study we investigated modification of the Ce(iii)/Ce(iv) ratio following internalization in human cells by X-ray absorption near edge spectroscopy (XANES). From this analysis on cell pellets, we observed that CNPs incubated for 24 h showed a significant increase in Ce(iii). By coupling on individual cells synchrotron micro-X-ray fluorescence (μXRF) with micro-XANES (μXANES) we demonstrated that the Ce(iii)/Ce(iv) ratio is also dependent on CNP intracellular localization. The regions with the highest CNP concentrations, suggested to be endolysosomes by transmission electron microscopy, were characterized by Ce atoms in the Ce(iv) oxidation state, while a higher Ce(iii) content was observed in regions surrounding these areas. These observations suggest that the interaction of CNPs with cells involves a complex mechanism in which different cellular areas play different roles.

  3. Effect of corrosion and stress-corrosion cracking on pipe integrity and remaining life

    SciTech Connect

    Jaske, C.E.; Beavers, J.A.

    1996-07-01

    Process piping is often exposed to corrosive fluids. During service, such exposure may cause localized corrosion or stress-corrosion cracking that affects structural integrity. This paper presents a model that quantifies the effect of localized corrosion and stress-corrosion cracking on pipe failure stress. The model is an extension of those that have been developed for oil and gas pipelines. It accounts for both axial and hoop stress. Cracks are modeled using inelastic fracture mechanics. Both flow-stress and fracture-toughness dependent failure modes are addressed. Corrosion and crack-growth rates are used to predict remaining service life.

  4. Atmospheric corrosion and epoxy-coated reinforcement

    SciTech Connect

    Wheat, H.G.

    1998-12-31

    Atmospheric corrosion can have a tremendous effect on the ability of epoxy-coated reinforcement to maintain its effectiveness. Corrosive conditions can result in the coating becoming brittle and more susceptible to damage from handling. Atmospheric conditions can also enhance localized corrosion at holidays on the bars. Efforts to minimize these effects will be discussed.

  5. Zirconium for superior corrosion resistance

    SciTech Connect

    Bird, K.W.; Richardson, K.

    1997-03-01

    Zirconium is a transition element located along with sister elements titanium and hafnium in Group IVB of the periodic table. It is grayish white metal, with a density somewhat less than carbon steel. Zirconium is the ninth most common metallic element in the earth`s crust, and is more abundant than zinc, lead, nickel, or even copper. Zirconium is exceptionally resistant to corrosion by many common acids and alkalis. It is resistant to most organic acids, such as formic, acetic, lactic, and oxalic acids. It also has a high resistance to localized forms of corrosion, such as pitting, crevice corrosion, and stress corrosion cracking. Its corrosion resistance is caused by the formation of a dense, tenaciously adherent, chemically inert oxide film on the surface. This oxide film protects the base metal from both chemical and mechanical attack at temperatures up to about 400 C (750 F). This article describes zirconium`s formability, machinability, corrosion resistance, and several typical applications.

  6. Predictors of Local Recurrence After Rituximab Based Chemotherapy Alone in Stage III/IV DLBCL: Guiding Decisions for Consolidative Radiation

    PubMed Central

    Jegadeesh, Naresh; Rajpara, Raj; Esiashvili, Natia; Shi, Zheng; Liu, Yuan; Okwan-Duodu, Derrick; Flowers, Christopher R.; Khan, Mohammad K.

    2015-01-01

    Purpose The role of consolidative radiotherapy (RT) for stage III and IV DLBCL in the era of rituximab is not well defined. There is evidence that some patients with bulky disease may benefit, but patient selection criteria are not well established. We sought to identify a subset of patients who experienced a high local failure rate after receiving rituximab-based chemotherapy alone and hence may benefit from the addition of consolidative RT. Methods and Materials 211 stage III and IV DLBCL patients treated between August 1999 and January 2012 were reviewed. Of these, 89 had a complete response to systemic therapy including rituximab and received no initial RT. Kaplan-Meier analysis and Cox proportional hazards regression were performed with local recurrence (LR) as the primary outcome. Results Median follow-up was 43.9 months. 50% experienced LR at 5 years. In multivariate analysis tumor ≥ 5 cm and stage III disease were associated with increased risk of LR. Five year LR free survival for patients with ≥ 5 cm lesions were 47.4% versus 74.7% for patients with < 5cm lesions (p = 0.01). In patients with < 5 cm tumors, SUVmax was ≥15 in all patients with LR. Five year LR free survival was 100% in SUV < 15 versus 68.8% in SUV≥15 (p=0.10). Conclusions Advanced stage DLBCL patients who are stage III or with disease ≥ 5 cm appear to be at an increased risk for LR. Patients with < 5 cm disease and SUVmax≥15 may be at higher risk for LR. These patients may benefit from consolidative RT following chemoimmunotherapy. PMID:25863758

  7. Local Structures and Heterogeneity of Silica-Supported M(III) Sites Evidenced by EPR, IR, NMR, and Luminescence Spectroscopies.

    PubMed

    Delley, Murielle F; Lapadula, Giuseppe; Núñez-Zarur, Francisco; Comas-Vives, Aleix; Kalendra, Vidmantas; Jeschke, Gunnar; Baabe, Dirk; Walter, Marc D; Rossini, Aaron J; Lesage, Anne; Emsley, Lyndon; Maury, Olivier; Copéret, Christophe

    2017-07-05

    Grafting molecular precursors on partially dehydroxylated silica followed by a thermal treatment yields silica-supported M(III) sites for a broad range of metals. They display unique properties such as high activity in olefin polymerization and alkane dehydrogenation (M = Cr) or efficient luminescence properties (M = Yb and Eu) essential for bioimaging. Here, we interrogate the local structure of the M(III) surface sites obtained from two molecular precursors, amides M(N(SiMe3)2)3 vs siloxides (M(OSi(O(t)Bu)3)3·L with L = (THF)2 or HOSi(O(t)Bu)3 for M = Cr, Yb, Eu, and Y, by a combination of advanced spectroscopic techniques (EPR, IR, XAS, UV-vis, NMR, luminescence spectroscopies). For paramagnetic Cr(III), EPR (HYSCORE) spectroscopy shows hyperfine coupling to nitrogen only when the amide precursor is used, consistent with the presence of nitrogen neighbors. This changes their specific reactivity compared to Cr(III) sites in oxygen environments obtained from siloxide precursors: no coordination of CO and oligomer formation during the polymerization of ethylene due to the presence of a N-donor ligand. The presence of the N-ligand also affects the photophysical properties of Yb and Eu by decreasing their lifetime, probably due to nonradiative deactivation of excited states by N-H bonds. Both types of precursors lead to a distribution of surface sites according to reactivity for Cr, luminescence spectroscopy for Yb and Eu, and dynamic nuclear polarization surface-enhanced (89)Y NMR spectroscopy (DNP SENS). In particular, DNP SENS provides molecular-level information about the structure of surface sites by evidencing the presence of tri-, tetra-, and pentacoordinated Y-surface sites. This study provides unprecedented evidence and tools to assess the local structure of metal surface sites in relation to their chemical and physical properties.

  8. Observation of local radio emission associated with type III radio bursts and Langmuir waves

    NASA Technical Reports Server (NTRS)

    Reiner, M. J.; Stone, R. G.; Fainberg, J.

    1992-01-01

    The first clear detection of fundamental and harmonic radiation from the type III radio source region is presented. This radiation is characterized by its lack of frequency drift, its short rise and decay times, its relative weakness compared to the remotely observed radiation and its temporal coincidence with observed Langmuir waves. The observations were made with the radio and plasma frequency (URAP) receivers on the Ulysses spacecraft between about 1 and 2 AU from the Sun.

  9. 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.

  10. Aircraft Corrosion

    DTIC Science & Technology

    1981-08-01

    materials still under development which look promising for the future. Classical corrosion control involves attacking the problem from three standpoints...effective- ness CONTROL BOX MECHANICAL AND Intermittent operation and faulty frequency ELECTRICAL TUNING LINKAGE selection. AND MOTOR CONTACTS WATER TRAPS...F.Fink 7 CORROSION CONTROL MEASURES FOR MILITARY AIRCRAFT - PRESENT UK REQUIREMENTS AND FUTURE DEVELOPMENTS by V.C.R.McLoughlin 8 CORROSION PREVENTION

  11. Impact of Hearing Aid Technology on Outcomes in Daily Life III: Localization.

    PubMed

    Johnson, Jani A; Xu, Jingjing; Cox, Robyn M

    2017-07-11

    Compared to basic-feature hearing aids, premium-feature hearing aids have more advanced technologies and sophisticated features. The objective of this study was to explore the difference between premium-feature and basic-feature hearing aids in horizontal sound localization in both laboratory and daily life environments. We hypothesized that premium-feature hearing aids would yield better localization performance than basic-feature hearing aids. Exemplars of premium-feature and basic-feature hearing aids from two major manufacturers were evaluated. Forty-five older adults (mean age 70.3 years) with essentially symmetrical mild to moderate sensorineural hearing loss were bilaterally fitted with each of the four pairs of hearing aids. Each pair of hearing aids was worn during a 4-week field trial and then evaluated using laboratory localization tests and a standardized questionnaire. Laboratory localization tests were conducted in a sound-treated room with a 360°, 24-loudspeaker array. Test stimuli were high frequency and low frequency filtered short sentences. The localization test in quiet was designed to assess the accuracy of front/back localization, while the localization test in noise was designed to assess the accuracy of locating sound sources throughout a 360° azimuth in the horizontal plane. Laboratory data showed that unaided localization was not significantly different from aided localization when all hearing aids were combined. Questionnaire data showed that aided localization was significantly better than unaided localization in everyday situations. Regarding the difference between premium-feature and basic-feature hearing aids, laboratory data showed that, overall, the premium-feature hearing aids yielded more accurate localization than the basic-feature hearing aids when high-frequency stimuli were used, and the listening environment was quiet. Otherwise, the premium-feature and basic-feature hearing aids yielded essentially the same performance in

  12. 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…

  13. 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.

  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. Torus Fibrations and Localization of Index III. Equivariant Version and Its Applications

    NASA Astrophysics Data System (ADS)

    Fujita, Hajime; Furuta, Mikio; Yoshida, Takahiko

    2014-05-01

    This paper is the third of the series concerning the localization of the index of Dirac-type operators. In our previous papers we gave a formulation of index of Dirac-type operators on open manifolds under some geometric setting, whose typical example was given by the structure of a torus fiber bundle on the ends of the open manifolds. We introduce two equivariant versions of the localization. As an application, we give a proof of Guillemin-Sternberg's quantization conjecture in the case of torus action.

  17. Gd(III)-Labeled Peptide Nanofibers for Reporting on Biomaterial Localization in Vivo

    PubMed Central

    2015-01-01

    Bioactive supramolecular nanostructures are of great importance in regenerative medicine and the development of novel targeted therapies. In order to use supramolecular chemistry to design such nanostructures, it is extremely important to track their fate in vivo through the use of molecular imaging strategies. Peptide amphiphiles (PAs) are known to generate a wide array of supramolecular nanostructures, and there is extensive literature on their use in areas such as tissue regeneration and therapies for disease. We report here on a series of PA molecules based on the well-established β-sheet amino acid sequence V3A3 conjugated to macrocyclic Gd(III) labels for magnetic resonance imaging (MRI). These conjugates were shown to form cylindrical supramolecular assemblies using cryogenic transmission electron microscopy and small-angle X-ray scattering. Using nuclear magnetic relaxation dispersion analysis, we observed that thermal annealing of the nanostructures led to a decrease in water exchange lifetime (τm) of hundreds of nanoseconds only for molecules that self-assemble into nanofibers of high aspect ratio. We interpret this decrease to indicate more solvent exposure to the paramagnetic moiety on annealing, resulting in faster water exchange within angstroms of the macrocycle. We hypothesize that faster water exchange in the nanofiber-forming PAs arises from the dehydration and increase in packing density on annealing. Two of the self-assembling conjugates were selected for imaging PAs after intramuscular injections of the PA C16V3A3E3-NH2 in the tibialis anterior muscle of a murine model. Needle tracts were clearly discernible with MRI at 4 days postinjection. This work establishes Gd(III) macrocycle-conjugated peptide amphiphiles as effective tracking agents for peptide amphiphile materials in vivo over the timescale of days. PMID:24937195

  18. Chromosomal Localization and Restriction Fragment Length Polymorphism Analysis of Annexins III, IV, and V

    DTIC Science & Technology

    1990-08-01

    Huntington’s disease and cystic fibrosis have been localized by this type of linkage analysis (Gusella et al., 1983; Tsui et al., 1985; White et al...linked to Huntington’s disease . Nature 1983;306:234-238. Grundmann U, Amann E, Abel K-J, Kupper HA. Isolation and expression of cDNA coding for a new

  19. Evaluation of the National Science Foundation's Local Course Improvement Program, Volume III: Case Studies.

    ERIC Educational Resources Information Center

    Kulik, James A.; And Others

    This report is the third of three volumes describing the results of the evaluation of the National Science Foundation (NSF) Local Course Improvement (LOCI) program. This volume describes 12 project case studies undertaken as part of that evaluation. Three projects were designed to increase individualization of college science teaching; two…

  20. Corrosion of nickel-base alloys

    SciTech Connect

    Scarberry, R.C.

    1985-01-01

    The volume consists of three tutorial lectures and 18 contributed papers. The three tutorial lectures provide state-of-the-art background on the physical metallurgy of nickel-base alloys as it relates to corrosion. Also featured are the mechanisms and applications of these alloys and an insight into the corrosion testing techniques. The three tutorial lecture papers will help acquaint newcomers to this family of alloys with a thorough overview. The contributed papers are categorized into four major topics: general corrosion, stress corrosion cracking, fatigue and localized corrosion. Each topic is key-noted by one invited lecture followed by several contributed papers. The papers in the general corrosion section are wide ranging and cover the aspects of material selection, development of galvanic series in corrosive environments, corrosion resistance characteristics, hydrogen permeation and hydrogen embrittlement of nickel and some nickel-base alloys.

  1. Visualizing the Translocation and Localization of Bacterial Type III Effector Proteins by Using a Genetically Encoded Reporter System.

    PubMed

    Gawthorne, Jayde A; Audry, Laurent; McQuitty, Claire; Dean, Paul; Christie, John M; Enninga, Jost; Roe, Andrew J

    2016-05-01

    Bacterial type III secretion system (T3SS) effector proteins are critical determinants of infection for many animal and plant pathogens. However, monitoring of the translocation and delivery of these important virulence determinants has proved to be technically challenging. Here, we used a genetically engineered LOV (light-oxygen-voltage) sensing domain derivative to monitor the expression, translocation, and localization of bacterial T3SS effectors. We found the Escherichia coli O157:H7 bacterial effector fusion Tir-LOV was functional following its translocation and localized to the host cell membrane in discrete foci, demonstrating that LOV-based reporters can be used to visualize the effector translocation with minimal manipulation and interference. Further evidence for the versatility of the reporter was demonstrated by fusing LOV to the C terminus of the Shigella flexneri effector IpaB. IpaB-LOV localized preferentially at bacterial poles before translocation. We observed the rapid translocation of IpaB-LOV in a T3SS-dependent manner into host cells, where it localized at the bacterial entry site within membrane ruffles.

  2. Corrosion and corrosivity monitoring system

    NASA Astrophysics Data System (ADS)

    Braunling, Russ; Dietrich, Paul

    2005-05-01

    Honeywell International has developed and flight-tested a Corrosion and Corrosivity Monitoring System (C2MS). The C2MS detects galvanic corrosion in the main gearbox feet fasteners of helicopters. In addition, it monitors the environmental conditions inside the main floorboard compartment to determine the need for structural maintenance. The C2MS sensor on a main gearbox feet fastener sends a small electrical signal through the fastener and housing to measure the conductivity of the assembly. The measured conductivity value is used to determine if galvanic corrosion is present in the fastener assembly. The floorboard compartment sensors use a surrogate metal coupon to measure the corrosivity of the environment. The information from this sensor is used to recommend an extension to the calendar-based maintenance schedule. Fleet-wide information can be gathered by the system. The C2MS uses two Data Collection Units (DCUs) to store the corrosion data: one for the main gearbox feet fasteners and one for the main floorboard compartment. The DCU design addresses the issues of long battery life for the C2MS (greater than 2 years) and compactness. The data from the DCUs is collected by a personal digital assistant and downloaded to a personal computer where the corrosion algorithms reside. The personal computer display provides the location(s) of galvanic corrosion in the main gearbox feet fasteners as well as the recommended date for floorboard compartment maintenance. This paper discusses the methodology used to develop the C2MS software and hardware, presents the principles of the galvanic corrosion detection algorithm, and gives the laboratory and flight test results that document system performance in detecting galvanic corrosion (detection and false alarm rate). The paper also discusses the benefits of environmental sensors for providing a maintenance scheduling date.

  3. Hydrodynamic Models of Line-Driven Accretion Disk Winds III: Local Ionization Equilibrium

    NASA Technical Reports Server (NTRS)

    Pereyra, Nicolas Antonio; Kallman, Timothy R.; White, Nicholas E. (Technical Monitor)

    2002-01-01

    We present time-dependent numerical hydrodynamic models of line-driven accretion disk winds in cataclysmic variable systems and calculate wind mass-loss rates and terminal velocities. The models are 2.5-dimensional, include an energy balance condition with radiative heating and cooling processes, and includes local ionization equilibrium introducing time dependence and spatial dependence on the line radiation force parameters. The radiation field is assumed to originate in an optically thick accretion disk. Wind ion populations are calculated under the assumption that local ionization equilibrium is determined by photoionization and radiative recombination, similar to a photoionized nebula. We find a steady wind flowing from the accretion disk. Radiative heating tends to maintain the temperature in the higher density wind regions near the disk surface, rather than cooling adiabatically. For a disk luminosity L (sub disk) = solar luminosity, white dwarf mass M(sub wd) = 0.6 solar mass, and white dwarf radii R(sub wd) = 0.01 solar radius, we obtain a wind mass-loss rate of M(sub wind) = 4 x 10(exp -12) solar mass yr(exp -1) and a terminal velocity of approximately 3000 km per second. These results confirm the general velocity and density structures found in our earlier constant ionization equilibrium adiabatic CV wind models. Further we establish here 2.5D numerical models that can be extended to QSO/AGN winds where the local ionization equilibrium will play a crucial role in the overall dynamics.

  4. Studies on the fine structural localization of zinc iodide-osmium reaction in the brain. III. Some characteristics of localization in the synaptosomes.

    PubMed

    Halász, N; Joó, F; Karnushina, I

    1978-02-01

    Synaptosomes from rat cerebral cortex were impregnated in the zinc iodide--osmium (ZIO) solution. The fine structural localization of the ZIO impregnation product was studied and, in addition, the function-dependent features of the reaction were examined after electrical stimulation or potassium chloride treatment. It was revealed that: (i) Aldehyde prefixation resulted in an increase in the number of reactive synaptic vesicles in all types of synaptosomes; (ii) Electrical stimulation decreased the number of reactive vesicles in a voltage dependent manner; (iii) Potassium chloride treatment also reduced the reactivity of vesicles; the reduction was dependent on the concentration of potassium and duration of treatment; (iv) Experimental interventions leading to the release of neurotransmitters from the synaptic vesicles and to fatigue of the nerve terminals also resulted in a decrease of the ZIO-reaction product of synaptic vesicles in a manner proportional to the strength of stimuli.

  5. WINGS-SPE. III. Equivalent width measurements, spectral properties, and evolution of local cluster galaxies

    NASA Astrophysics Data System (ADS)

    Fritz, J.; Poggianti, B. M.; Cava, A.; Moretti, A.; Varela, J.; Bettoni, D.; Couch, W. J.; D'Onofrio D'Onofrio, M.; Dressler, A.; Fasano, G.; Kjærgaard, P.; Marziani, P.; Moles, M.; Omizzolo, A.

    2014-06-01

    Context. Cluster galaxies are the ideal sites to look at when studying the influence of the environment on the various aspects of the evolution of galaxies, such as the changes in their stellar content and morphological transformations. In the framework of wings, the WIde-field Nearby Galaxy-cluster Survey, we have obtained optical spectra for ~6000 galaxies selected in fields centred on 48 local (0.04 < z < 0.07) X-ray selected clusters to tackle these issues. Aims: By classifying the spectra based on given spectral lines, we investigate the frequency of the various spectral types as a function of both the clusters' properties and the galaxies' characteristics. In this way, using the same classification criteria adopted for studies at higher redshift, we can consistently compare the properties of the local cluster population to those of their more distant counterparts. Methods: We describe a method that we have developed to automatically measure the equivalent width of spectral lines in a robust way, even in spectra with a non optimal signal-to-noise ratio. This way, we can derive a spectral classification reflecting the stellar content, based on the presence and strength of the [Oii] and Hδ lines. Results: After a quality check, we are able to measure 4381 of the ~6000 originally observed spectra in the fields of 48 clusters, of which 2744 are spectroscopically confirmed cluster members. The spectral classification is then analysed as a function of galaxies' luminosity, stellar mass, morphology, local density, and host cluster's global properties and compared to higher redshift samples (MORPHS and EDisCS). The vast majority of galaxies in the local clusters population are passive objects, being also the most luminous and massive. At a magnitude limit of MV < -18, galaxies in a post-starburst phase represent only ~11% of the cluster population, and this fraction is reduced to ~5% at MV < -19.5, which compares to the 18% at the same magnitude limit for high

  6. Fungal-induced corrosion of wire rope

    SciTech Connect

    Little, B.; Ray, R.; Hart, K.; Wagner, P.

    1995-10-01

    Localized corrosion of carbon steel wire rope stored in a humid environment on wooden spools was caused by organic acid and carbon dioxide production by fungi growing directly on the wood. Fungal growth was found on the interior so the wooden spools, and corrosion was most severe on the wrap of wire in direct contact with the wood. Laboratory experiments and an extensive review of the literature demonstrated causal relationships between storage conditions and fungal growth and localized corrosion.

  7. The cellular uptake and localization of non-emissive iridium(III) complexes as cellular reaction-based luminescence probes.

    PubMed

    Li, Chunyan; Liu, Yi; Wu, Yongquan; Sun, Yun; Li, Fuyou

    2013-01-01

    Improvement of cellular uptake and subcellular resolution remains a major obstacle in the successful and broad application of cellular optical probes. In this context, we design and synthesize seven non-emissive cyclometalated iridium(III) solvent complexes [Ir(CˆN)(2)(solv)(2)](+)L(-) (LIr2-LIr8, in which CˆN = 2-phenylpyridine (ppy) or its derivative; solv = DMSO, H(2)O or CH(3)CN; L(-) = PF(6)(-) or OTf(-)) applicable in live cell imaging to facilitate selective visualization of cellular structures. Based on the above variations (including different counter ions, solvent ligands, and CˆN ligands), structure-activity relationship analyses reveal a number of clear correlations: (1) variations in counter anions and solvent ligands of iridium(III) complexes do not affect cellular imaging behavior, and (2) length of the side carbon chain in CˆN ligands has significant effects on cellular uptake and localization/accumulation of iridium complexes in living cells. Moreover, investigation of the uptake mechanism via low-temperature and metabolism inhibitor assays reveal that [Ir(4-Meppy)(2)(CH(3)CN)(2)](+)OTf(-) (LIr5) with 2-phenylpyridine derivative with side-chain of methyl group at the 4-position as CˆN ligand permeates the outer and nuclear membranes of living cells through an energy-dependent, non-endocytic entry pathway, and translocation of the complex from the cell periphery towards the perinuclear region possibly occurs through a microtubule-dependent transport pathway. Nuclear pore complexes (NPCs) appear to selectively control the transport of iridium(III) complexes between the cytoplasm and nucleus. A generalization of trends in behavior and structure-activity relationships is presented, which should provide further insights into the design and optimization of future probes. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. IpaD Localizes to the Tip of the Type III Secretion System Needle of Shigella flexneri

    PubMed Central

    Espina, Marianela; Olive, Andrew J.; Kenjale, Roma; Moore, David S.; Ausar, S. Fernando; Kaminski, Robert W.; Oaks, Edwin V.; Middaugh, C. Russell; Picking, William D.; Picking, Wendy L.

    2006-01-01

    Shigella flexneri, the causative agent of shigellosis, is a gram-negative bacterial pathogen that initiates infection by invading cells within the colonic epithelium. Contact with host cell surfaces induces a rapid burst of protein secretion via the Shigella type III secretion system (TTSS). The first proteins secreted are IpaD, IpaB, and IpaC, with IpaB and IpaC being inserted into the host cell membrane to form a pore for translocating late effectors into the target cell cytoplasm. The resulting pathogen-host cross talk results in localized actin polymerization, membrane ruffling, and, ultimately, pathogen entry. IpaD is essential for host cell invasion, but its role in this process is just now coming to light. IpaD is a multifunctional protein that controls the secretion and presentation of IpaB and IpaC at the pathogen-host interface. We show here that antibodies recognizing the surface-exposed N terminus of IpaD neutralize Shigella's ability to promote pore formation in erythrocyte membranes. We further show that MxiH and IpaD colocalize on the bacterial surface. When TTSS needles were sheared from the Shigella surface, IpaD was found at only the needle tips. Consistent with this, IpaD localized to the exposed tips of needles that were still attached to the bacterium. Molecular analyses then showed that the IpaD C terminus is required for this surface localization and function. Furthermore, mutations that prevent IpaD surface localization also eliminate all IpaD-related functions. Thus, this study demonstrates that IpaD localizes to the TTSA needle tip, where it functions to control the secretion and proper insertion of translocators into host cell membranes. PMID:16861624

  9. KEPLER ECLIPSING BINARY STARS. III. CLASSIFICATION OF KEPLER ECLIPSING BINARY LIGHT CURVES WITH LOCALLY LINEAR EMBEDDING

    SciTech Connect

    Matijevic, Gal; Prsa, Andrej; Orosz, Jerome A.; Welsh, William F.; Bloemen, Steven; Barclay, Thomas E-mail: andrej.prsa@villanova.edu

    2012-05-15

    We present an automated classification of 2165 Kepler eclipsing binary (EB) light curves that accompanied the second Kepler data release. The light curves are classified using locally linear embedding, a general nonlinear dimensionality reduction tool, into morphology types (detached, semi-detached, overcontact, ellipsoidal). The method, related to a more widely used principal component analysis, produces a lower-dimensional representation of the input data while preserving local geometry and, consequently, the similarity between neighboring data points. We use this property to reduce the dimensionality in a series of steps to a one-dimensional manifold and classify light curves with a single parameter that is a measure of 'detachedness' of the system. This fully automated classification correlates well with the manual determination of morphology from the data release, and also efficiently highlights any misclassified objects. Once a lower-dimensional projection space is defined, the classification of additional light curves runs in a negligible time and the method can therefore be used as a fully automated classifier in pipeline structures. The classifier forms a tier of the Kepler EB pipeline that pre-processes light curves for the artificial intelligence based parameter estimator.

  10. 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.

  11. PROBING THE LOCAL BUBBLE WITH DIFFUSE INTERSTELLAR BANDS. III. THE NORTHERN HEMISPHERE DATA AND CATALOG

    SciTech Connect

    Farhang, Amin; Khosroshahi, Habib G.; Javadi, Atefeh; Van Loon, Jacco Th.

    2015-02-01

    We present new high signal-to-noise ratio (S/N) observations of the diffuse interstellar bands (DIBs) in the Local Bubble and its surroundings. We observed 432 sightlines and obtain the equivalent widths of the λ5780 and λ5797 Å DIBs up to a distance of ∼200 pc. All of the observations were carried out using the Intermediate Dispersion Spectrograph on the 2.5 m Isaac Newton Telescope, during three years, to reach a minimum S/N of ∼2000. All of the λ5780 and λ5797 absorptions are presented in this paper and we tabulate the observed values of the interstellar parameters, λ5780, λ5797, Na ID{sub 1}, and Na ID{sub 2}, including the uncertainties.

  12. Probing the Local Bubble with Diffuse Interstellar Bands. III. The Northern Hemisphere Data and Catalog

    NASA Astrophysics Data System (ADS)

    Farhang, Amin; Khosroshahi, Habib G.; Javadi, Atefeh; van Loon, Jacco Th.

    2015-02-01

    We present new high signal-to-noise ratio (S/N) observations of the diffuse interstellar bands (DIBs) in the Local Bubble and its surroundings. We observed 432 sightlines and obtain the equivalent widths of the λ5780 and λ5797 Å DIBs up to a distance of ~200 pc. All of the observations were carried out using the Intermediate Dispersion Spectrograph on the 2.5 m Isaac Newton Telescope, during three years, to reach a minimum S/N of ~2000. All of the λ5780 and λ5797 absorptions are presented in this paper and we tabulate the observed values of the interstellar parameters, λ5780, λ5797, Na ID1, and Na ID2, including the uncertainties.

  13. AE analysis during corrosion, stress corrosion cracking and corrosion fatigue processes

    SciTech Connect

    Yuyama, S.; Kishi, T.

    1983-01-01

    Current theoretical and experimental research on the use of acoustic emission (AE) techniques for studying corrosion problems is reviewed. In particular, attention is given to the AE behavior of Type 304 stainless steel in aqueous environment, and a new method for analyzing corrosion, stress corrosion cracking, and corrosion fatigue in Type 304 steel is described. Results are also presented for other steels, aluminum and magnesium alloys, copper and its alloys, uranium alloys, and titanium and zirconium alloys. It is concluded that the AE method is a prommising approach to the detection and monitoring of localized corrosion in both laboratory specimens and engineering structures. Care must be taken, however, to discriminate valid AE signals from the background noise and to interpret the results correctly. 95 references.

  14. 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.

  15. [The semi-occlusive dressing in treating Allen III and IV fingertip injuries as an alternative to local skin flaps].

    PubMed

    Quadlbauer, S; Pezzei, Ch; Jurkowitsch, J; Beer, T; Keuchel, T; Hausner, T; Leixnering, M

    2016-09-14

    Fingertip injuries are very common in emergency departments. According to the literature, Allen III and IV fingertip injuries should be treated with local skin flaps. Instead, we have treated these kinds of injuries in recent years with a semi-occlusive dressing. The main purpose of this study was to evaluate the outcome after semi-occlusive dressing therapy with respect to soft tissue cover, recovery of sensibility and duration of disability. We retrospectively analysed 77 fingertip injuries (39 Allen I, 25 Allen II, 9 Allen III, 4 Allen IV) from 2008-2011 in 23 women and 54 men who were treated with a semi-occlusive dressing. The mean age was 36 ± 14 years and the mean follow-up was seven months. The bone was not shortened even if the bone was exposed up to the wound level. The primarily occlusive dressing was left as long as possible and was sealed when necessary. Furthermore, the treatment time with the semi-occlusive dressing and the period of disability was recorded. Patient sensitivity recovery was also analysed. The mean treatment duration was 21 ± 10 days and the mean duration of disability was 30 ± 17 days. The mean duration of disability was 19 ± 8 days for Allen I injuries, 36 ± 16 days for Allen II, 45 ± 20 days for Allen III and 58 ± 7 days for Allen IV. All patients developed satisfactory tissue cover and sensibility recovery. For amputation injuries of Allen III and IV, we recorded a normal light-touch 2‑point discrimination in the Semmes-Weinstein Test in 77 % and diminished in 23 %. There were no complications like tissue infections, neuroma or osteitis. Also, no secondary flap supply was necessary. The semi-occlusive dressing is a good therapy for all kind of fingertip injuries, regardless of the amputation level. Even if the bone is exposed up to the wound level, satisfactory soft tissue cover can be achieved.

  16. Studies of Schwann cell proliferation. III. Evidence for the surface localization of the neurite mitogen

    PubMed Central

    1980-01-01

    In the preceding paper (Salzer et al., 1980, J. Cell Biol. 84:753-- 766), evidence was presented that a neurite membrane fraction could be used to stimulate Schwann cell proliferation in culture. In this study, we present evidence that the mitogenic signal by which intact neurites or neurite membranes stimulate Schwann cell proliferation is located at the neurite surface. This conclusion is based on the following observations: (a) stimulation of Schwann cell proliferation by neurons requires direct contact between neurites and Schwann cells, separation of the two cells by a permeable collagen diaphragm 6 microns thick prevents Schwann cell proliferation; (b) treatment of intact neurites with trypsin before preparation of neurite membranes abolishes the ability of these membranes to be mitogenic for Schwann cells; and (c) the mitogenic activity of neurite homogenates is exclusively localized in the particulate rather than the soluble fraction of the homogenate. The mitogenic component on the neurite surface is heat labile, and is inactivated by aldehyde fixation. Preliminary data suggest that the mitogenic effect of neurite on Schwann cells is not mediated by 3',5'- cyclic AMP. PMID:6153659

  17. Local Group dSph radio survey with ATCA (III): constraints on particle dark matter

    SciTech Connect

    Regis, Marco; Colafrancesco, Sergio; Profumo, Stefano; De Blok, W.J.G.; Massardi, Marcella; Richter, Laura E-mail: sergio.colafrancesco@wits.ac.za E-mail: blok@astron.nl E-mail: laura@ska.ac.za

    2014-10-01

    We performed a deep search for radio synchrotron emissions induced by weakly interacting massive particles (WIMPs) annihilation or decay in six dwarf spheroidal (dSph) galaxies of the Local Group. Observations were conducted with the Australia Telescope Compact Array (ATCA) at 16 cm wavelength, with an rms sensitivity better than 0.05 mJy/beam in each field. In this work, we first discuss the uncertainties associated with the modeling of the expected signal, such as the shape of the dark matter (DM) profile and the dSph magnetic properties. We then investigate the possibility that point-sources detected in the proximity of the dSph optical center might be due to the emission from a DM cuspy profile. No evidence for an extended emission over a size of few arcmin (which is the DM halo size) has been detected. We present the associated bounds on the WIMP parameter space for different annihilation/decay final states and for different astrophysical assumptions. If the confinement of electrons and positrons in the dSph is such that the majority of their power is radiated within the dSph region, we obtain constraints on the WIMP annihilation rate which are well below the thermal value for masses up to few TeV. On the other hand, for conservative assumptions on the dSph magnetic properties, the bounds can be dramatically relaxed. We show however that, within the next 10 years and regardless of the astrophysical assumptions, it will be possible to progressively close in on the full parameter space of WIMPs by searching for radio signals in dSphs with SKA and its precursors.

  18. Phase I/II Trial Evaluating Carbon Ion Radiotherapy for Salvaging Treatment of Locally Recurrent Nasopharyngeal Carcinoma

    PubMed Central

    Kong, Lin; Hu, Jiyi; Guan, Xiyin; Gao, Jing; Lu, Rong; Lu, Jiade J.

    2016-01-01

    Background: Radiation therapy is the mainstay strategy for the treatment of nasopharyngeal cancer (NPC). Intensity-modulated X-ray therapy (IMXT) alone is the current standard for stage I and II NPC. For stage III and IV A/B diseases, concurrent chemotherapy should be provided in addition to IMXT. However, optimal treatment for locally recurrent NPC after previous definitive dose of radiotherapy is lacking. Various techniques including brachytherapy, IMXT, stereotactic radiosurgery or radiotherapy (SRS or SBRT) have been used in the management of locally recurrent NPC. Due to the inherent limitation of these techniques, i.e., limited range of irradiation or over-irradiation to surrounding normal tissues, moderate efficacy has been observed at the cost of severe toxicities. Carbon ion radiotherapy (CIRT) offers potential physical and biological advantages over photon and proton radiotherapy. Due to the inverted dose profile of particle beams and their greater energy deposition within the Bragg peak, precise dose delivery to the target volume(s) without exposing the surrounding organs at risk to extra doses is possible. In addition, CIRT provides an increased relative biological effectiveness (RBE) as compared to photon and proton radiotherapy. Such advantages may translate to improved outcomes after irradiation in terms of disease control in radio-resistant and previously treated, recurrent malignancies. It is therefore reasonable to postulate that recurrent NPC after high-dose radiotherapy could be more resistant to re-irradiation using photons. Reports on the treatment of radio-resistant malignancies in the head and neck region such as melanoma, sarcoma, and adenoid cystic carcinoma (ACC) have demonstrated superior local control rates from CIRT as compared to photon irradiation. Thus patients with recurrent NPC are likely to benefit from the enhanced biological effectiveness of carbon ions. As effective retreatment strategy is lacking for locally recurrent NPC

  19. Phase I/II Trial Evaluating Carbon Ion Radiotherapy for Salvaging Treatment of Locally Recurrent Nasopharyngeal Carcinoma.

    PubMed

    Kong, Lin; Hu, Jiyi; Guan, Xiyin; Gao, Jing; Lu, Rong; Lu, Jiade J

    2016-01-01

    Radiation therapy is the mainstay strategy for the treatment of nasopharyngeal cancer (NPC). Intensity-modulated X-ray therapy (IMXT) alone is the current standard for stage I and II NPC. For stage III and IV A/B diseases, concurrent chemotherapy should be provided in addition to IMXT. However, optimal treatment for locally recurrent NPC after previous definitive dose of radiotherapy is lacking. Various techniques including brachytherapy, IMXT, stereotactic radiosurgery or radiotherapy (SRS or SBRT) have been used in the management of locally recurrent NPC. Due to the inherent limitation of these techniques, i.e., limited range of irradiation or over-irradiation to surrounding normal tissues, moderate efficacy has been observed at the cost of severe toxicities. Carbon ion radiotherapy (CIRT) offers potential physical and biological advantages over photon and proton radiotherapy. Due to the inverted dose profile of particle beams and their greater energy deposition within the Bragg peak, precise dose delivery to the target volume(s) without exposing the surrounding organs at risk to extra doses is possible. In addition, CIRT provides an increased relative biological effectiveness (RBE) as compared to photon and proton radiotherapy. Such advantages may translate to improved outcomes after irradiation in terms of disease control in radio-resistant and previously treated, recurrent malignancies. It is therefore reasonable to postulate that recurrent NPC after high-dose radiotherapy could be more resistant to re-irradiation using photons. Reports on the treatment of radio-resistant malignancies in the head and neck region such as melanoma, sarcoma, and adenoid cystic carcinoma (ACC) have demonstrated superior local control rates from CIRT as compared to photon irradiation. Thus patients with recurrent NPC are likely to benefit from the enhanced biological effectiveness of carbon ions. As effective retreatment strategy is lacking for locally recurrent NPC, carbon ion

  20. PH and Electrochemical Responsive Materials for Corrosion Smart Coating Applications

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2008-01-01

    Corrosion is a costly issue for military operations and civil industries. While most corrosion initiates from localized corrosion form, such as pitting, failure directly caused by localized corrosion is the most dangerous kind, because it is difficult to anticipate and prevent, occurs very suddenly and can be catastrophic. One way of preventing these failures is with a coating that can detect and heal localized corrosion. pH and other electrochemical changes are often associated with localized corrosion, so it is expected that materials that are pH or otherwise electrochemical responsive can be used to detect and control corrosion. This paper will review various pH and electrochemical responsive materials and their potential applications in corrosion smart coatings. Current research results in this field will also be reported.

  1. Is there role of additional chemotherapy after definitive local treatment for stage I/II marginal zone lymphoma?: Consortium for Improving Survival of Lymphoma (CISL) study.

    PubMed

    Koh, Myeong Seok; Kim, Won Seog; Kim, Seok Jin; Oh, Sung Yong; Yoon, Dok Hyun; Lee, Soon Il; Hong, Junshik; Song, Moo Kon; Shin, Ho-Jin; Kwon, Jung Hye; Kim, Hyo Jung; Do, Yong Rok; Suh, Cheolwon; Kim, Hyo Jin

    2015-10-01

    Even though local stage (Ann Arbor stage I/II) marginal zone lymphoma (MZL) is well controlled with local treatment-based therapy, no data exist on the role of additional chemotherapy after local treatment for stage I/II MZL. Patients with biopsy-confirmed Ann Arbor stage I/II MZL (n = 210) were included for analysis in this study. Of these, 180 patients (85.7 %) were stage I and 30 (14.3 %) were stage II. Most patients (n = 182, 86.7 %) were treated with a local modality including radiation therapy or surgery and 28 (13.3 %) received additional systemic chemotherapy after local treatment. The overall response rate was 98.3 % (95 % CI 96-100 %), with 187 complete responses and 20 partial responses. In the local treatment group, the mean progression-free survival (PFS) was 147.4 months (95 % CI 126.7-168.1 months) and the overall survival (OS) was 188.2 months (95 % CI 178.8-197.7 months). In the additional chemotherapy group, the mean PFS was 103.4 months (95 % CI 84.9-121.9 months) and the OS was 137.3 months (95 % CI 127.9-146.7 months). There was no difference between the two groups in OS (p = 0.836) and PFS (p = 0.695). Local stage MZL has a good clinical course and is well controlled with a local treatment modality without additional chemotherapy.

  2. Localization of types I, II, and III collagen mRNAs in developing human skeletal tissues by in situ hybridization

    PubMed Central

    1987-01-01

    Paraffin sections of human skeletal tissues were studied in order to identify cells responsible for production of types I, II, and III collagens by in situ hybridization. Northern hybridization and sequence information were used to select restriction fragments of cDNA clones for the corresponding mRNAs to obtain probes with a minimum of cross- hybridization. The specificity of the probes was proven in hybridizations to sections of developing fingers: osteoblasts and chondrocytes, known to produce only one type of fibrillar collagen each (I and II, respectively) were only recognized by the corresponding cDNA probes. Smooth connective tissues exhibited variable hybridization intensities with types I and III collagen cDNA probes. The technique was used to localize the activity of type II collagen production in the different zones of cartilage during the growth of long bones. Visual inspection and grain counting revealed the highest levels of pro alpha 1(II) collagen mRNAs in chondrocytes of the lower proliferative and upper hypertrophic zones of the growth plate cartilage. This finding was confirmed by Northern blotting of RNAs isolated from epiphyseal (resting) cartilage and from growth zone cartilage. Analysis of the osseochondral junction revealed virtually no overlap between hybridization patterns obtained with probes specific for type I and type II collagen mRNAs. Only a fraction of the chondrocytes in the degenerative zone were recognized by the pro alpha 1(II) collagen cDNA probe, and none by the type I collagen cDNA probe. In the mineralizing zone virtually all cells were recognized by the type I collagen cDNA probe, but only very few scattered cells appeared to contain type II collagen mRNA. These data indicate that in situ hybridization is a valuable tool for identification of connective tissue cells which are actively producing different types of collagens at the various stages of development, differentiation, and growth. PMID:3558480

  3. A phase I/II study of neoadjuvant liposomal doxorubicin, paclitaxel, and hyperthermia in locally advanced breast cancer.

    PubMed

    Vujaskovic, Zeljko; Kim, Dong W; Jones, Ellen; Lan, Lan; McCall, Linda; Dewhirst, Mark W; Craciunescu, Oana; Stauffer, Paul; Liotcheva, Vlayka; Betof, Allison; Blackwell, Kimberly

    2010-01-01

    The prognosis for locally advanced breast cancer (LABC) patients continues to be poor, with an estimated five-year survival of only 50-60%. Preclinical data demonstrates enhanced therapeutic efficacy with liposomal encapsulation of doxorubicin combined with hyperthermia (HT). Therefore this phase I/II study was designed to evaluate the safety and efficacy of a novel neoadjuvant combination treatment of paclitaxel, liposomal doxorubicin, and hyperthermia. Eligible patients received four cycles of neoadjuvant liposomal doxorubicin (30-75 mg/m(2)), paclitaxel (100-175 mg/m(2)), and hyperthermia. They subsequently underwent either a modified radical mastectomy or lumpectomy with axillary node dissection followed by radiation therapy and then eight cycles of CMF (cyclophosphamide, methotrexate, 5-fluorouracil) chemotherapy. Forty-seven patients with stage IIB-III LABC were enrolled and 43 patients were evaluable. Fourteen patients (33%) had inflammatory breast cancer. Combined (partial + complete) clinical response rate was 72% and combined pathological response rate was 60%. Four patients achieved a pathologically complete response. Sixteen patients were eligible for breast-conserving surgery. The cumulative equivalent minutes (CEM 43) at T90 (tenth percentile of temperature distribution) was significantly greater for those with a pathological response. Four-year disease-free survival was 63% (95% CI, 46%-76%) and the four-year overall survival was 75% (95% CI, 58-86%). Neoadjuvant therapy using paclitaxel, liposomal doxorubicin and hyperthermia is a feasible and well tolerated treatment strategy in patients with LABC. The thermal dose parameter CEM 43 T90 was significantly correlated with attaining a pathological response.

  4. A phase I/II study of neoadjuvant liposomal doxorubicin, paclitaxel, and hyperthermia in locally advanced breast cancer

    PubMed Central

    Vujaskovic, Zeljko; Kim, Dong W.; Jones, Ellen; Lan, Lan; McCall, Linda; Dewhirst, Mark W.; Craciunescu, Oana; Stauffer, Paul; Liotcheva, Vlayka; Betof, Allison; Blackwell, Kimberly

    2010-01-01

    Purpose The prognosis for locally advanced breast cancer (LABC) patients continues to be poor, with an estimated five-year survival of only 50–60%. Preclinical data demonstrates enhanced therapeutic efficacy with liposomal encapsulation of doxorubicin combined with hyperthermia (HT). Therefore this phase I/II study was designed to evaluate the safety and efficacy of a novel neoadjuvant combination treatment of paclitaxel, liposomal doxorubicin, and hyperthermia. Materials and methods Eligible patients received four cycles of neoadjuvant liposomal doxorubicin (30–75 mg/m2), paclitaxel (100–175 mg/m2), and hyperthermia. They subsequently underwent either a modified radical mastectomy or lumpectomy with axillary node dissection followed by radiation therapy and then eight cycles of CMF (cyclophosphamide, methotrexate, 5-fluorouracil) chemotherapy. Results Forty-seven patients with stage IIB-III LABC were enrolled and 43 patients were evaluable. Fourteen patients (33%) had inflammatory breast cancer. Combined (partial + complete) clinical response rate was 72% and combined pathological response rate was 60%. Four patients achieved a pathologically complete response. Sixteen patients were eligible for breast-conserving surgery. The cumulative equivalent minutes (CEM 43) at T90 (tenth percentile of temperature distribution) was significantly greater for those with a pathological response. Four-year disease-free survival was 63% (95% CI, 46%–76%) and the four-year overall survival was 75% (95% CI, 58–86%). Conclusions Neoadjuvant therapy using paclitaxel, liposomal doxorubicin and hyperthermia is a feasible and well tolerated treatment strategy in patients with LABC. The thermal dose parameter CEM 43 T90 was significantly correlated with attaining a pathological response. PMID:20377362

  5. Thymostimulin versus placebo for palliative treatment of locally advanced or metastasised hepatocellular carcinoma: a phase III clinical trial

    PubMed Central

    2010-01-01

    Background Thymostimulin is a thymic peptide fraction with immune-mediated cytotoxicity against hepatocellular carcinoma (HCC) in vitro and palliative efficacy in advanced HCC in two independent phase II trials. The aim of this study was to assess the efficacy of thymostimulin in a phase III trial. Methods The study was designed as a prospective randomised, placebo-controlled, double-blind, multicenter clinical phase III trial. Between 10/2002 and 03/2005, 135 patients with locally advanced or metastasised HCC (Karnofsky ≥60%/Child-Pugh ≤ 12) were randomised to receive thymostimulin 75 mg s.c. 5×/week or placebo stratified according to liver function. Primary endpoint was twelve-month survival, secondary endpoints overall survival (OS), time to progression (TTP), tumor response, safety and quality of life. A subgroup analysis according to liver function, KPS and tumor stage (Okuda, CLIP and BCLC) formed part of the protocol. Results Twelve-month survival was 28% [95%CI 17-41; treatment] and 32% [95%CI 19-44; control] with no significant differences in median OS (5.0 [95% CI 3.7-6.3] vs. 5.2 [95% CI 3.5-6.9] months; p = 0.87, HR = 1.04 [95% CI 0.7-1.6]) or TTP (5.3 [95%CI 2.0-8.6] vs. 2.9 [95%CI 2.6-3.1] months; p = 0.60, HR = 1.13 [95% CI 0.7-1.8]). Adjustment for liver function, Karnofsky status or tumor stage did not affect results. While quality of life was similar in both groups, fewer patients on thymostimulin suffered from accumulating ascites and renal failure. Conclusions In our phase III trial, we found no evidence of any benefit to thymostimulin in the treatment of advanced HCC and there is therefore no justification for its use as single-agent treatment. The effect of thymostimulin on hepato-renal function requires further confirmation. Trial Registration Current Controlled Trials ISRCTN64487365. PMID:20735834

  6. Thymostimulin versus placebo for palliative treatment of locally advanced or metastasised hepatocellular carcinoma: a phase III clinical trial.

    PubMed

    Dollinger, Matthias M; Lautenschlaeger, Christine; Lesske, Joachim; Tannapfel, Andrea; Wagner, Anna-Dorothea; Schoppmeyer, Konrad; Nehls, Oliver; Welker, Martin-Walter; Wiest, Reiner; Fleig, Wolfgang E

    2010-08-24

    Thymostimulin is a thymic peptide fraction with immune-mediated cytotoxicity against hepatocellular carcinoma (HCC) in vitro and palliative efficacy in advanced HCC in two independent phase II trials. The aim of this study was to assess the efficacy of thymostimulin in a phase III trial. The study was designed as a prospective randomised, placebo-controlled, double-blind, multicenter clinical phase III trial. Between 10/2002 and 03/2005, 135 patients with locally advanced or metastasised HCC (Karnofsky >or=60%/Child-Pugh III trial, we found no evidence of any benefit to thymostimulin in the treatment of advanced HCC and there is therefore no justification for its use as single-agent treatment. The effect of thymostimulin on hepato-renal function requires further confirmation. Current Controlled Trials ISRCTN64487365.

  7. 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

  8. CO sub 2 induced inhibition of the localized corrosion of aluminum, Al-0. 5% Cu, and Al-2% Cu in dilute HF solution

    SciTech Connect

    Scully, J.R. . Dept. of Materials Science); Peebles, D.E. )

    1991-01-01

    This study presents work on corrosion of aluminum, Al-.5% Cu, and Al-2% Cu. Electrochemical tests were performed in dilute HF solutions both with and without CO{sub 2} sparging. It is suggested that CO{sub 2} or its reaction products interact with the passive film so that exposure of Cu in the oxide-solution interface is minimized. CO{sub 2} is investigated as a corrosion inhibitor. 4 refs. (JDL)

  9. 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.

  10. The poloidal distribution of type-III edge localized modes in the Mega-Ampere spherical tokamak (MAST)

    SciTech Connect

    Antar, G.Y.

    2006-05-15

    This article describes the poloidal plasma particle distribution of type-III edge localized modes (ELMs) in the Mega-Ampere spherical tokamak [R.-J. Akers et al., Phys. Plasmas 9, 3919 (2002)]. A fast imaging camera with 10 {mu}s exposure time is used to record the D{sub {alpha}} light coming from the entire poloidal cross section. Furthermore, three sets of probes, triggered at the same time, acquired at 1 MHz, and located at different poloidal, radial, and toroidal locations in the tokamak are used. ELMs are observed to affect the D{sub {alpha}} emission throughout the low-field scrape-off layer; on the high-field side, however, this effect is found to be small. The results obtained by imaging agree with the pointwise measurements using Langmuir probes. The radial propagation is shown to occur at a speed of 250 m/s, whereas the toroidal convection from the top to the bottom of the plasma is shown to be consistent with a transport at the local sound speed. Strong correlation amplitudes are reported among the probes that are poloidally and toroidally separated by several meters. The study of the cross-correlation coefficients as a function of the frequency indicates that this correlation is caused by the low-frequency component of the signal and that the high-frequency part is not correlated. Consequently, the filamentary structures are interpreted as caused by the onset of turbulence during an ELM and do not constitute the ELM itself.

  11. An investigation of the corrosion properties of aluminum-tantalum alloys using electrochemical impedance spectroscopy and local electrochemical impedance spectroscopy

    SciTech Connect

    Lillard, R.S.

    1993-01-01

    An investigation of passivity of single phase Al-Ta alloys and the contribution of the second phase, Al3Ta, to breakdown is presented. In 0.1M NaCl buffered to pH 7 with boric acid and sodium borate the passive current density of pure aluminum was found to be approximately 0.3 microamps/cm(exp 2), the passive current densities of Al 4 at percent Ta, Al 8 at percent Ta were found to be 2.5 and 2.4 microamps/cm(exp 2) respectively while the pitting potentials of these alloys were approximately 500 mV greater than that of pure aluminum. Traditional EIS measurements in 0.5M boric acid 0.05M sodium borate solution found the impedance values of the Al-4Ta and Al-8Ta were found to be 5.6 x 10(exp 4) and 3.1 x 10(exp 4) ohm cm(exp 2) respectively while that of pure aluminum was found to be about 1.2 x 10(exp 5) ohm cm(exp 2). In addition, the thickness of the oxide film on the alloys to be less than that of pure aluminum in all solutions examined. Similar results were obtained for chloride containing solutions. These results indicate that there is no correlation between passive current density and the breakdown potential; that is the passive current density and the breakdown potential are two unrelated phenomena. The results of Local Electrochemical Impedance Spectroscopy (LEIS) experiments on a heat treated Al 1.5 at percent Ta alloy, which contained Al3Ta precipitates, revealed that the capacitance of the film over the precipitate is higher than the capacitance of the film over the aluminum portion of this electrode. This indicates that thickness of the film over the precipitate is thinner than the film over aluminum. This interface, between the oxide over the Al3Ta precipitates and the oxide over the aluminum matrix, is perceived as being incoherent and is interpreted here as a 'residual flaw', as described by the crack/heal mechanism proposed by Wood et al.

  12. 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.

  13. Phase I/II study of trastuzumab, paclitaxel, cisplatin and radiation for locally advanced, HER2 overexpressing, esophageal adenocarcinoma

    SciTech Connect

    Safran, Howard . E-mail: hsafran@lifespan.org; Di Petrillo, Thomas; Akerman, Paul; Ng, Thomas; Evans, Devon; Steinhoff, Margaret; Benton, David; Purviance, John; Goldstein, Lisa; Tantravahi, Umadevi; Kennedy, Teresa R.N.

    2007-02-01

    Purpose: To determine the overall survival for patients with locally advanced, HER2 overexpressing, esophageal adenocarcinoma receiving trastuzumab, paclitaxel, cisplatin, and radiation on a Phase I-II study. Methods and Materials: Patients with adenocarcinoma of the esophagus without distant organ metastases and 2+/3+ HER2 overexpression by immunohistochemistry (IHC) were eligible. All patients received cisplatin 25 mg/m{sup 2} and paclitaxel 50 mg/m{sup 2} weekly for 6 weeks with radiation therapy (RT) 50.4 Gy. Patients received trastuzumab at dose levels of 1, 1.5, or 2 mg/kg weekly for 5 weeks after an initial bolus of 2, 3, or 4 mg/kg. Results: Nineteen patients were entered: 7 (37%) had celiac adenopathy, and 7 (37%) had retroperitoneal, portal adenopathy, or scalene adenopathy. Fourteen of 19 patients (74%) had either 3+ HER2 expression by immunohistochemistry, or an increase in HER2 gene copy number by HER2 gene amplification or high polysomy by fluorescence in situ hybridization. The median survival of all patients was 24 months and the 2-year survival was 50%. Conclusions: Assessment of the effect of trastuzumab in the treatment of patients with esophageal adenocarcinoma overexpressing HER2 is limited by the small number of patients in this study. Overall survival, however, was similar to prior studies without an increase in toxicity. Evaluation of HER2 status should be performed in future trials for patients with adenocarcinoma of the esophagus that investigate therapies targeting the HER family.

  14. Boric Acid Corrosion of Concrete Rebar

    NASA Astrophysics Data System (ADS)

    Pabalan, R. T.; Yang, L.; Chiang, K.–T.

    2013-07-01

    Borated water leakage through spent fuel pools (SFPs) at pressurized water reactors is a concern because it could cause corrosion of reinforcement steel in the concrete structure and compromise the integrity of the structure. Because corrosion rate of carbon steel in concrete in the presence of boric acid is lacking in published literature and available data are equivocal on the effect of boric acid on rebar corrosion, corrosion rate measurements were conducted in this study using several test methods. Rebar corrosion rates were measured in (i) borated water flowing in a simulated concrete crack, (ii) borated water flowing over a concrete surface, (iii) borated water that has reacted with concrete, and (iv) 2,400 ppm boric acid solutions with pH adjusted to a range of 6.0 to 7.7. The corrosion rates were measured using coupled multielectrode array sensor (CMAS) and linear polarization resistance (LPR) probes, both made using carbon steel. The results indicate that rebar corrosion rates are low (~1 μm/yr or less)when the solution pH is ~7.1 or higher. Below pH ~7.1, the corrosion rate increases with decreasing pH and can reach ~100 μm/yr in solutions with pH less than ~6.7. The threshold pH for carbon steel corrosion in borated solution is between 6.8 and 7.3.

  15. 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.

  16. Randomized Phase III Trial of Adjuvant Pazopanib Versus Placebo After Nephrectomy in Patients With Localized or Locally Advanced Renal Cell Carcinoma.

    PubMed

    Motzer, Robert J; Haas, Naomi B; Donskov, Frede; Gross-Goupil, Marine; Varlamov, Sergei; Kopyltsov, Evgeny; Lee, Jae Lyun; Melichar, Bohuslav; Rini, Brian I; Choueiri, Toni K; Zemanova, Milada; Wood, Lori A; Reaume, M Neil; Stenzl, Arnulf; Chowdhury, Simon; Lim, Ho Yeong; McDermott, Ray; Michael, Agnieszka; Bao, Weichao; Carrasco-Alfonso, Marlene J; Aimone, Paola; Voi, Maurizio; Doehn, Christian; Russo, Paul; Sternberg, Cora N

    2017-09-13

    Purpose This phase III trial evaluated the efficacy and safety of pazopanib versus placebo in patients with locally advanced renal cell carcinoma (RCC) at high risk for relapse after nephrectomy. Patients and Methods A total of 1,538 patients with resected pT2 (high grade) or ≥ pT3, including N1, clear cell RCC were randomly assigned to pazopanib or placebo for 1 year; 403 patients received a starting dose of 800 mg or placebo. To address toxicity attrition, the 800-mg starting dose was lowered to 600 mg, and the primary end point analysis was changed to disease-free survival (DFS) for pazopanib 600 mg versus placebo (n = 1,135). Primary analysis was performed after 350 DFS events in the intent-to-treat (ITT) pazopanib 600 mg group (ITT600mg), and DFS follow-up analysis was performed 12 months later. Secondary end point analyses included DFS with ITT pazopanib 800 mg (ITT800mg) and safety. Results The primary analysis results of DFS ITT600mg favored pazopanib but did not show a significant improvement over placebo (hazard ratio [HR], 0.86; 95% CI, 0.70 to 1.06; P = .165). The secondary analysis of DFS in ITT800mg (n = 403) yielded an HR of 0.69 (95% CI, 0.51 to 0.94). Follow-up analysis in ITT600mg yielded an HR of 0.94 (95% CI, 0.77 to 1.14). Increased ALT and AST were common adverse events leading to treatment discontinuation in the pazopanib 600 mg (ALT, 16%; AST, 5%) and 800 mg (ALT, 18%; AST, 7%) groups. Conclusion The results of the primary DFS analysis of pazopanib 600 mg showed no benefit over placebo in the adjuvant setting.

  17. 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.

  18. AMCOM Corrosion Program Overview

    DTIC Science & Technology

    2011-08-01

    and Control (CPC)/NDT Training – CPC Sustainment Technology • Corrosion Repair Kits; Dehumidification ; Corrosion Preventive Compounds; Protective...Program Dehumidification (DH) Project Aviation Technical Supply Humid & Corrosive Environment Stores $ 17M Unique High Value Parts $92K

  19. A STUDY OF CORROSION AND STRESS CORROSION CRACKING OF CARBON STEEL NUCLEAR WASTE STORAGE TANKS

    SciTech Connect

    BOOMER, K.D.

    2007-08-21

    The Hanford reservation Tank Farms in Washington State has 177 underground storage tanks that contain approximately 50 million gallons of liquid legacy radioactive waste from cold war plutonium production. These tanks will continue to store waste until it is treated and disposed. These nuclear wastes were converted to highly alkaline pH wastes to protect the carbon steel storage tanks from corrosion. However, the carbon steel is still susceptible to localized corrosion and stress corrosion cracking. The waste chemistry varies from tank to tank, and contains various combinations of hydroxide, nitrate, nitrite, chloride, carbonate, aluminate and other species. The effect of each of these species and any synergistic effects on localized corrosion and stress corrosion cracking of carbon steel have been investigated with electrochemical polarization, slow strain rate, and crack growth rate testing. The effect of solution chemistry, pH, temperature and applied potential are all considered and their role in the corrosion behavior will be discussed.

  20. CORROSION OF HIGH-TEMPERATURE ALLOYS

    SciTech Connect

    John P. Hurley; John P. Kay

    1999-10-01

    corrosion resistance alone. Strength and creep tests were not performed. Based only their corrosion resistance, Alloys RA310 and TP310 were shown to be the best suited to resist chlorine in a combustion environment. These alloys produced protective chromium oxide layers, displayed more general rather than localized corrosion, and their additives did not react to provide conduits for further corrosion.

  1. 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.

  2. Effective representation of amide III, II, I, and A modes on local vibrational modes: Analysis of ab initio quantum calculation results

    NASA Astrophysics Data System (ADS)

    Hahn, Seungsoo

    2016-10-01

    The Hamiltonian matrix for the first excited vibrational states of a protein can be effectively represented by local vibrational modes constituting amide III, II, I, and A modes to simulate various vibrational spectra. Methods for obtaining the Hamiltonian matrix from ab initio quantum calculation results are discussed, where the methods consist of three steps: selection of local vibrational mode coordinates, calculation of a reduced Hessian matrix, and extraction of the Hamiltonian matrix from the Hessian matrix. We introduce several methods for each step. The methods were assessed based on the density functional theory calculation results of 24 oligopeptides with four different peptide lengths and six different secondary structures. The completeness of a Hamiltonian matrix represented in the reduced local mode space is improved by adopting a specific atom group for each amide mode and reducing the effect of ignored local modes. The calculation results are also compared to previous models using C=O stretching vibration and transition dipole couplings. We found that local electric transition dipole moments of the amide modes are mainly bound on the local peptide planes. Their direction and magnitude are well conserved except amide A modes, which show large variation. Contrary to amide I modes, the vibrational coupling constants of amide III, II, and A modes obtained by analysis of a dipeptide are not transferable to oligopeptides with the same secondary conformation because coupling constants are affected by the surrounding atomic environment.

  3. Effective representation of amide III, II, I, and A modes on local vibrational modes: Analysis of ab initio quantum calculation results.

    PubMed

    Hahn, Seungsoo

    2016-10-28

    The Hamiltonian matrix for the first excited vibrational states of a protein can be effectively represented by local vibrational modes constituting amide III, II, I, and A modes to simulate various vibrational spectra. Methods for obtaining the Hamiltonian matrix from ab initio quantum calculation results are discussed, where the methods consist of three steps: selection of local vibrational mode coordinates, calculation of a reduced Hessian matrix, and extraction of the Hamiltonian matrix from the Hessian matrix. We introduce several methods for each step. The methods were assessed based on the density functional theory calculation results of 24 oligopeptides with four different peptide lengths and six different secondary structures. The completeness of a Hamiltonian matrix represented in the reduced local mode space is improved by adopting a specific atom group for each amide mode and reducing the effect of ignored local modes. The calculation results are also compared to previous models using C=O stretching vibration and transition dipole couplings. We found that local electric transition dipole moments of the amide modes are mainly bound on the local peptide planes. Their direction and magnitude are well conserved except amide A modes, which show large variation. Contrary to amide I modes, the vibrational coupling constants of amide III, II, and A modes obtained by analysis of a dipeptide are not transferable to oligopeptides with the same secondary conformation because coupling constants are affected by the surrounding atomic environment.

  4. Domain structure of antithrombin III. Tentative localization of the heparin binding region using /sup 1/H NMR spectroscopy

    SciTech Connect

    Gettins, P.; Wooten, E.W.

    1987-07-14

    The denaturation of human and bovine antithrombin III by guanidine hydrochloride has been followed by /sup 1/H NMR spectroscopy. The same unfolding transition seen previously from circular dichroism studies at low denaturant concentration was detected here by discontinuous changes in the chemical shifts of the C(2) protons of two of the five histidines in human antithrombin III and of three of the six histidines in bovine antithrombin III. These two histidines in human antithrombin III are assigned to residue 1 and, more tentatively, to residue 65. Two of the three histidines similarly affected in the bovine protein appear to be homologous to residues in the human protein. This supports the proposal of similar structures for the two proteins. In the presence of heparin, the discontinuous titration behavior of these histidine resonances is shifted to higher denaturant concentration, reflecting the stabilization of the easily unfolded first domain of the protein by bound heparin. From the tentative assignment of one of these resonances to histidine-1, it is proposed that the heparin binding site of antithrombin III is located in the N-terminal region and that this region forms a separate domain from the rest of the protein. The pattern of disulfide linkages is such that this domain may well extend from residue 1 to at least residue 128. Thermal denaturation also leads to major perturbation of these two histidine resonances in human antithrombin III, though stable intermediates in the unfolding were not detected.

  5. 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.

  6. Localization, by linkage analysis, of the cystinuria type III gene to chromosome 19q13.1

    SciTech Connect

    Bisceglia, L.; Totaro, A.; Melchionda, S.

    1997-03-01

    Cystinuria is an autosomal recessive aminoaciduria in which three urinary phenotypes (I, II, and III) have been described. An amino acid transporter gene, SLC3A1 (formerly rBAT), was found to be responsible for this disorder. Mutational and linkage analysis demonstrated the presence of genetic heterogeneity in which the SLC3A1 gene is responsible for type I cystinuria but not for type II or type III. In this study, we report the identification of the cystinuria type III locus on the long arm of chromosome 19 (19q13.1), obtained after a genomewide search. Pairwise linkage analysis in a series of type III or type II families previously excluded from linkage to the cystinuria type I locus (SLC3A1 gene) revealed a significant maximum LOD score (Z{sub max}) of 13.11 at a maximum recombination fraction ({theta}{sub max}) of .00, with marker D19S225. Multipoint linkage analysis performed with the use of additional markers from the region placed the cystinuria type III locus between D19S414 and D19S220. Preliminary data on type II families also seem to place the disease locus for this rare type of cystinuria at 19q13.1 (significant Z{sub max} = 3.11 at {theta}{sub max} of .00, with marker D19S225). 33 refs., 2 figs., 1 tab.

  7. Localization, by linkage analysis, of the cystinuria type III gene to chromosome 19q13.1.

    PubMed Central

    Bisceglia, L; Calonge, M J; Totaro, A; Feliubadaló, L; Melchionda, S; García, J; Testar, X; Gallucci, M; Ponzone, A; Zelante, L; Zorzano, A; Estivill, X; Gasparini, P; Nunes, V; Palacín, M

    1997-01-01

    Cystinuria is an autosomal recessive aminoaciduria in which three urinary phenotypes (I, II, and III) have been described. An amino acid transporter gene, SLC3A1 (formerly rBAT), was found to be responsible for this disorder. Mutational and linkage analysis demonstrated the presence of genetic heterogeneity in which the SLC3A1 gene is responsible for type I cystinuria but not for type II or type III. In this study, we report the identification of the cystinuria type III locus on the long arm of chromosome 19 (19q13.1), obtained after a genomewide search. Pairwise linkage analysis in a series of type III or type II families previously excluded from linkage to the cystinuria type I locus (SLC3A1 gene) revealed a significant maximum LOD score (zeta max) of 13.11 at a maximum recombination fraction (theta max) of .00, with marker D19S225. Multipoint linkage analysis performed with the use of additional markers from the region placed the cystinuria type III locus between D19S414 and D19S220. Preliminary data on type II families also seem to place the disease locus for this rare type of cystinuria at 19q13.1 (significant zeta max = 3.11 at theta max of .00, with marker D19S225). PMID:9042921

  8. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Johnsey, M. N.; Li, W.; Buhrow, J. W.; Calle, L. M.; Pearman, B. P.; Zhang, X.

    2015-01-01

    This work concerns the development of smart coating technologies based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of corrosion inhibitors into coating which provides protection through corrosion-controlled release of these inhibitors.One critical aspect of a corrosion protective smart coating is the selection of corrosion inhibitor for encapsulation and comparison of the inhibitor function before and after encapsulation. For this purpose, a systematic approach is being used to evaluate free and encapsulated corrosion inhibitors by salt immersion. Visual, optical microscope, and Scanning Electron Microscope (with low-angle backscatter electron detector) are used to evaluate these inhibitors. It has been found that the combination of different characterization tools provide an effective method for evaluation of early stage localized corrosion and the effectiveness of corrosion inhibitors.

  9. Corrosion-resistant high-entropy alloys: A review

    DOE PAGES

    Shi, Yunzhu; Yang, Bin; Liaw, Peter

    2017-02-05

    Corrosion destroys more than three percent of the world’s gross domestic product. Therefore, the design of highly corrosion-resistant materials is urgently needed. By breaking the classical alloy-design philosophy, high-entropy alloys (HEAs) possess unique microstructures, which are solid solutions with random arrangements of multiple elements. The particular locally-disordered chemical environment is expected to lead to unique corrosion-resistant properties. In this review, the studies of the corrosion-resistant HEAs during the last decade are summarized. The corrosion-resistant properties of HEAs in various aqueous environments and the corrosion behavior of HEA coatings are presented. The effects of environments, alloying elements, and processing methods onmore » the corrosion resistance are analyzed in detail. Finally, the possible directions of future work regarding the corrosion behavior of HEAs are suggested.« less

  10. A Review Corrosion of TI Grade 7 and Other TI Alloys in Nuclear Waste Repository Environments

    SciTech Connect

    F. Hua; K. Mon; P. Pasupathi; G. Gordon

    2004-05-11

    Titanium alloy degradation modes are reviewed in relation to their performance in repository environments. General corrosion, localized corrosion, stress corrosion cracking, hydrogen induced cracking, microbially influenced corrosion, and radiation-assisted corrosion of Ti alloys are considered. With respect to the Ti Grade 7 drip shields selected for emplacement in the repository at Yucca Mountain, general corrosion, hydrogen induced cracking, and radiation-assisted corrosion will not lead to failure within the 10,000 year regulatory period; stress corrosion cracking (in the absence of disruptive events) is of no consequence to barrier performance; and localized corrosion and microbially influenced corrosion are not expected to occur. To facilitate the discussion, Ti Grades 2, 5, 7, 9, 11, 12, 16, 17, 18, and 24 are included in this review.

  11. Local lymphocytes and nitric oxide synthase in the uterine cervical stroma of patients with grade III cervical intraepithelial neoplasia.

    PubMed

    Silva, Cléber Sergioda da; Michelin, Marcia Antoniazi; Etchebehere, Renata Margarida; Adad, Sheila Jorge; Murta, Eddie Fernando Candido

    2010-06-01

    Precancerous and cancerous cells can trigger an immune response that may limit tumor development and can be used as a prognostic marker. The aims of the present study were to quantify the presence of B and T lymphocytes, macrophages and cells expressing inducible nitric oxide synthase (iNOS) in the cervical stroma of women with grade III cervical intraepithelial neoplasia (CIN III) or in the intratumoral and peritumoral tissue of women with stage I invasive carcinoma. Cervical tissue specimens were obtained from 60 women (20 each from control tissues, CIN III and invasive carcinomas). The average ages in the control, CIN III and invasive groups were 43.9 (+/- 4.3), 35.5 (+/- 9.5), and 50 (+/- 11.2) years, respectively. The specimens were immunohistochemically labeled with antibodies to identify T lymphocytes (CD3), cytotoxic lymphocytes (CD8), B lymphocytes (CD20), macrophages (CD68) and iNOS. We evaluated the markers in the stroma above the squamocolumnar junction (control), at the intraepithelial lesion (CIN cases), and in the infiltrating tumor. Two independent observers performed the immunohistochemical analysis. T lymphocytes, B lymphocytes, macrophages and iNOS were present more frequently (P<0.05) in the stroma of peritumoral invasive tumors compared to the controls and intratumoral invasive cancer samples. CD3+ and CD20+ lymphocytes were present more frequently in CIN III patients compared to samples from patients with intratumoral invasive cancer (P<0.05). High numbers of T and B lymphocytes, macrophages and iNOS-expressing cells in the peritumoral stroma of the invasive tumors were observed. Cell migration appeared to be proportional to the progression of the lesion.

  12. Local Lymphocytes and Nitric Oxide Synthase in the Uterine Cervical Stroma of Patients with Grade III Cervical Intraepithelial Neoplasia

    PubMed Central

    da Silva, Cléber Sergioda; Michelin, Marcia Antoniazi; Etchebehere, Renata Margarida; Adad, Sheila Jorge; Murta, Eddie Fernando Candido

    2010-01-01

    OBJECTIVES: Precancerous and cancerous cells can trigger an immune response that may limit tumor development and can be used as a prognostic marker. The aims of the present study were to quantify the presence of B and T lymphocytes, macrophages and cells expressing inducible nitric oxide synthase (iNOS) in the cervical stroma of women with grade III cervical intraepithelial neoplasia (CIN III) or in the intratumoral and peritumoral tissue of women with stage I invasive carcinoma. METHODS: Cervical tissue specimens were obtained from 60 women (20 each from control tissues, CIN III and invasive carcinomas). The average ages in the control, CIN III and invasive groups were 43.9 (± 4.3), 35.5 (± 9.5), and 50 (± 11.2) years, respectively. The specimens were immunohistochemically labeled with antibodies to identify T lymphocytes (CD3), cytotoxic lymphocytes (CD8), B lymphocytes (CD20), macrophages (CD68) and iNOS. We evaluated the markers in the stroma above the squamocolumnar junction (control), at the intraepithelial lesion (CIN cases), and in the nfiltrating tumor. Two independent observers performed the immunohistochemical analysis. RESULTS: T lymphocytes, B lymphocytes, macrophages and iNOS were present more frequently (P<0.05) in the stroma of peritumoral invasive tumors compared to the controls and intratumoral invasive cancer samples. CD3+ and CD20+ lymphocytes were present more frequently in CIN III patients compared to samples from patients with intratumoral invasive cancer (P<0.05). CONCLUSION: High numbers of T and B lymphocytes, macrophages and iNOS-expressing cells in the peritumoral stroma of the invasive tumors were observed. Cell migration appeared to be proportional to the progression of the lesion. PMID:20613932

  13. Theoretical study of one-electron-oxidized salen complexes of group 7 (Mn(iii), Tc(iii), and Re(iii)) and group 10 metals (Ni(ii), Pd(ii), and Pt(ii)) with the 3D-RISM-GMC-QDPT method: localized vs. delocalized ground and excited states in solution.

    PubMed

    Aono, Shinji; Nakagaki, Masayuki; Sakaki, Shigeyoshi

    2017-06-28

    One-electron oxidized salen complexes of Mn(iii) and Ni(ii) were recently reported to be unique mixed-valence compounds. Their electronic structures are sensitive to the salen ligand and solvation. We systematically investigated a series of one-electron oxidized salen complexes of group 7 metals (Mn(iii), Tc(iii), and Re(iii)) and their group 10 analogues (Ni(ii), Pd(ii), and Pt(ii)) using the general multi-configuration reference quasi-degenerate perturbation theory (GMC-QDPT) which was combined with the three-dimensional reference interaction site model self-consistent field theory (3D-RISM-SCF) to incorporate the solvation effect. The calculated absorption spectra and electronic structures agree with the experimental observation. The one-electron oxidized salen complexes of group 10 metals with a symmetrical salen ligand have a delocalized electronic structure belonging to class III (Robin-Day classification) in weakly polar solvents. The tendency for taking a delocalized electronic structure increases in the order Pd(ii) < Ni(ii) < Pt(ii). When the salen ligand is asymmetrical, the one-electron oxidized complexes have a localized electronic structure belonging to class II. The group 7 analogues of Mn(iii) and Tc(iii) have a localized electronic structure belonging to class II even in weakly polar solvents and even with a symmetrical salen ligand. However, the one-electron oxidized Re(iii) complex has no mixed-valence nature because one-electron oxidation occurs on the Re center. Theoretical study shows that the solvation effect plays a crucial role in determining the mixed-valence character, class II or III, and thereby its incorporation in the calculation is indispensable for correctly describing geometries, electronic structures, and the inter-valence absorption spectra of these complexes. The d orbital energy is one of the most important factors for determining the localization/delocalization electronic structures in these complexes. Detailed discussion of

  14. Predictors of Local Recurrence After Rituximab-Based Chemotherapy Alone in Stage III and IV Diffuse Large B-Cell Lymphoma: Guiding Decisions for Consolidative Radiation

    SciTech Connect

    Jegadeesh, Naresh; Rajpara, Raj; Esiashvili, Natia; Shi, Zheng; Liu, Yuan; Okwan-Duodu, Derrick; Flowers, Christopher R.; Khan, Mohammad K.

    2015-05-01

    Purpose: The role of consolidative radiation therapy (RT) for stage III and IV diffuse large B-cell lymphoma (DLBCL) in the era of rituximab is not well defined. There is evidence that some patients with bulky disease may benefit, but patient selection criteria are not well established. We sought to identify a subset of patients who experienced a high local failure rate after receiving rituximab-based chemotherapy alone and hence may benefit from the addition of consolidative RT. Methods and Materials: Two hundred eleven patients with stage III and IV DLBCL treated between August 1999 and January 2012 were reviewed. Of these, 89 had a complete response to systemic therapy including rituximab and received no initial RT. Kaplan-Meier analysis and Cox proportional hazards regression were performed, with local recurrence (LR) as the primary outcome. Results: The median follow-up time was 43.9 months. Fifty percent of patients experienced LR at 5 years. In multivariate analysis, tumor ≥5 cm and stage III disease were associated with increased risk of LR. The 5-year LR-free survival was 47.4% for patients with ≥5-cm lesions versus 74.7% for patients with <5-cm lesions (P=.01). In patients with <5-cm tumors, the maximum standardized uptake value (SUVmax) was ≥15 in all patients with LR. The 5-year LR-free survival was 100% in SUV<15 versus 68.8% in SUV≥15 (P=.10). Conclusions: Advanced-stage DLBCL patients with stage III disease or with disease ≥5 cm appear to be at an increased risk for LR. Patients with <5-cm disease and SUVmax ≥15 may be at higher risk for LR. These patients may benefit from consolidative RT after chemoimmunotherapy.

  15. Predictors of local recurrence after rituximab-based chemotherapy alone in stage III and IV diffuse large B-cell lymphoma: guiding decisions for consolidative radiation.

    PubMed

    Jegadeesh, Naresh; Rajpara, Raj; Esiashvili, Natia; Shi, Zheng; Liu, Yuan; Okwan-Duodu, Derrick; Flowers, Christopher R; Khan, Mohammad K

    2015-05-01

    The role of consolidative radiation therapy (RT) for stage III and IV diffuse large B-cell lymphoma (DLBCL) in the era of rituximab is not well defined. There is evidence that some patients with bulky disease may benefit, but patient selection criteria are not well established. We sought to identify a subset of patients who experienced a high local failure rate after receiving rituximab-based chemotherapy alone and hence may benefit from the addition of consolidative RT. Two hundred eleven patients with stage III and IV DLBCL treated between August 1999 and January 2012 were reviewed. Of these, 89 had a complete response to systemic therapy including rituximab and received no initial RT. Kaplan-Meier analysis and Cox proportional hazards regression were performed, with local recurrence (LR) as the primary outcome. The median follow-up time was 43.9 months. Fifty percent of patients experienced LR at 5 years. In multivariate analysis, tumor ≥ 5 cm and stage III disease were associated with increased risk of LR. The 5-year LR-free survival was 47.4% for patients with ≥ 5-cm lesions versus 74.7% for patients with <5-cm lesions (P=.01). In patients with <5-cm tumors, the maximum standardized uptake value (SUVmax) was ≥ 15 in all patients with LR. The 5-year LR-free survival was 100% in SUV<15 versus 68.8% in SUV ≥ 15 (P=.10). Advanced-stage DLBCL patients with stage III disease or with disease ≥ 5 cm appear to be at an increased risk for LR. Patients with <5-cm disease and SUVmax ≥ 15 may be at higher risk for LR. These patients may benefit from consolidative RT after chemoimmunotherapy. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Corrosion protection by sonoelectrodeposited organic films on zinc coated steel.

    PubMed

    Et Taouil, Abdeslam; Mahmoud, Mahmoud Mourad; Lallemand, Fabrice; Lallemand, Séverine; Gigandet, Marie-Pierre; Hihn, Jean-Yves

    2012-11-01

    A variety of coatings based on electrosynthesized polypyrrole were deposited on zinc coated steel in presence or absence of ultrasound, and studied in terms of corrosion protection. Cr III and Cr VI commercial passivation were used as references. Depth profiling showed a homogeneous deposit for Cr III, while SEM imaging revealed good surface homogeneity for Cr VI layers. These chromium-based passivations ensured good protection against corrosion. Polypyrrole (PPy) was also electrochemically deposited on zinc coated steel with and without high frequency ultrasound irradiation in aqueous sodium tartrate-molybdate solution. Such PPy coatings act as a physical barrier against corrosive species. PPy electrosynthesized in silent conditions exhibits similar properties to Cr VI passivation with respect to corrosion protection. Ultrasound leads to more compact and more homogeneous surface structures for PPy, as well as to more homogeneous distribution of doping molybdate anions within the film. Far better corrosion protection is exhibited for such sonicated films.

  17. Corrosion resistance of porous NiTi biomedical alloy in simulated body fluids

    NASA Astrophysics Data System (ADS)

    Stergioudi, F.; Vogiatzis, C. A.; Pavlidou, E.; Skolianos, S.; Michailidis, N.

    2016-09-01

    The corrosion performance of two porous NiTi in physiological and Hank’s solutions was investigated by potentiodynamic polarization, cyclic polarization and impedance spectroscopy. Electric models simulating the corrosion mechanism at early stages of immersion were proposed, accounting for both microstructural observations and electrochemical results. Results indicate that both porous samples were susceptible to localized corrosion. The porosity increase (from 7% to 18%) resulted in larger and wider pore openings, thus favoring the corrosion resistance of 18% porous NiTi. Strengthening of corrosion resistance was observed in Hank’s solution. The pore morphology and micro-galvanic corrosion phenomena were determining factors affecting the corrosion resistance.

  18. USE OF COUPLED MULTI-ELECTRODE ARRAYS TO ADVANCE THE UNDERSTANDING OF SELECTED CORROSION PHENOMENA

    SciTech Connect

    N.D. Budiansky; F. Bocher; H. Cong; M.F. Hurley; J.R. Scully

    2006-02-23

    The use of multi-coupled electrode arrays in various corrosion applications is discussed with the main goal of advancing the understanding of various corrosion phenomena. Both close packed and far spaced electrode configurations are discussed. Far spaced electrode arrays are optimized for high throughput experiments capable of elucidating the effects of various variables on corrosion properties. For instance the effects of a statistical distribution of flaws on corrosion properties can be examined. Close packed arrays enable unprecedented spatial and temporal information on the behavior of local anodes and cathodes. Interactions between corrosion sites can trigger or inhibit corrosion phenomena and affect corrosion damage evolution.

  19. Engineering Task Plan for Fourth Generation Hanford Corrosion Monitoring System

    SciTech Connect

    NORMAN, E.C.

    2000-06-20

    This Engineering Task Plan (ETP) describes the activities associated with the installation of cabinets containing corrosion monitoring equipment on tanks 241-AN-102 and 241-AN-107. The new cabinets (one per tank) will be installed adjacent to existing corrosion probes already installed in riser WST-RISER-016 on both tanks. The corrosion monitoring equipment to be installed utilizes the technique of electrochemical noise (EN) for monitoring waste tank corrosion. Typically, EN consists of low frequency (4 Hz) and small amplitude signals that are spontaneously generated by electrochemical reactions occurring at corroding or other surfaces. EN analysis is well suited for monitoring and identifying the onset of localized corrosion, and for measuring uniform corrosion rates. A typical EN based corrosion-monitoring system measures instantaneous fluctuations in corrosion current and potential between three nominally identical electrodes of the material of interest immersed in the environment of interest. Time-dependent fluctuations in corrosion current are described by electrochemical current noise, and time-dependent fluctuations of corrosion potential are described by electrochemical noise. The corrosion monitoring systems are designed to detect the onset of localized corrosion phenomena if tank conditions should change to allow these phenomena to occur. In addition to the EN technique, the systems also facilitate the use of the Linear Polarization Resistance (LPR) technique to collect uniform corrosion rate information. LPR measures the linearity at the origin of the polarization curve for overvoltages up to a few millivolts away from the rest potential or natural corrosion potential. The slope of the current vs. voltage plot gives information on uniform corrosion rates.

  20. Histology of the Oral Mucosa in Patients With BRONJ at III Stage: A Microscopic Study Proves the Unsuitability of Local Mucosal Flaps

    PubMed Central

    Lorenzo, Sara Di; Trapassi, Alberto; Corradino, Bartolo; Cordova, Adriana

    2013-01-01

    Background Bisphosphonate Osteonecrosis of the Jaw (BRONJ) is a newly recognized condition reported in patients treated with aminobisphosphonates (BF). BRONJ is defined as the presence of exposed necrotic alveolar bone that does not resolve over a period of 8 weeks in a patient taking bisphosphonates who has not had radiotherapy to the jaw. Treatment protocols have been outlined, but trials and outcomes of treatment and long-term follow-up data are not yet available. In 2004 an expert panel outlined recommendations for the management of bisphosphonate-associated osteonecrosis of the jaws. Through the histological study of the oral mucosa over the bone necrosis and around the osteonecrosis area in 8 patients affected by BRONJ at III stage, the authors highlight the inappropriateness of the local mucosal flaps to cover the losses of substance of the jaw, BF-related. Methods Mucosa tissue was taken from 8 patients, affected by BRONJ, III stage. The samples taken from the mucosa around and over the osteonecrosis area were fixed with formalin and an ematossilina-eosin dichromatic coloring was carried out. Results The samples of mucosa showed pathognomonic signs of cell suffering that prove that in these patients using local mucosa flaps is inappropriate. Conclusions The authors suggest that only a well vascularized flap as free flap must be used to cover the osteonecrosis area in patients with BRONJ stage III. Because of the structural instability of the mucosa in patients suffering of osteonecrosis Bf related the local flaps are prone to ulceration and to relapse. PMID:23390472

  1. 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 ...

  2. 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 ...

  3. Hot corrosion of the B2 nickel aluminides

    NASA Technical Reports Server (NTRS)

    Ellis, David L.

    1993-01-01

    The hot corrosion behavior of the B2 nickel aluminides was studied to determine the inherent hot corrosion resistance of the beta nickel aluminides and to develop a mechanism for the hot corrosion of the beta nickel aluminides. The effects of the prior processing of the material, small additions of zirconium, stoichiometry of the materials, and preoxidation of the samples were also examined. Additions of 2, 5, and 15 w/o chromium were used to determine the effect of chromium on the hot corrosion of the beta nickel aluminides and the minimum amount of chromium necessary for good hot corrosion resistance. The results indicate that the beta nickel aluminides have inferior inherent hot corrosion resistance despite their excellent oxidation resistance. Prior processing and zirconium additions had no discernible effect on the hot corrosion resistance of the alloys. Preoxidation extended the incubation period of the alloys only a few hours and was not considered to be an effective means of stopping hot corrosion. Stoichiometry was a major factor in determining the hot corrosion resistance of the alloys with the higher aluminum alloys having a definitely superior hot corrosion resistance. The addition of chromium to the alloys stopped the hot corrosion attack in the alloys tested. From a variety of experimental results, a complex hot corrosion mechanism was proposed. During the early stages of the hot corrosion of these alloys the corrosion is dominated by a local sulphidation/oxidation form of attack. During the intermediate stages of the hot corrosion, the aluminum depletion at the surface leads to a change in the oxidation mechanism from a protective external alumina layer to a mixed nickel-aluminum spinel and nickel oxide that can occur both externally and internally. The material undergoes extensive cracking during the later portions of the hot corrosion.

  4. 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.

  5. Does the Zone of Injury in Combat-Related Type III Open Tibia Fractures Preclude the Use of Local Soft Tissue Coverage?

    DTIC Science & Technology

    2010-11-01

    procedure. J Bone Joint Surg Am. 2001;83:239 246. 6. Burgess AR, Poka A, Brumback RJ , et al. Management of open grade III tibial fractures. Orthop Clin...extremities with failed free flaps: a single institution’s experience over 25 years. Ann Plast Surg. 2007;59:18 21. 19. Fix RJ , Vasconez LO...of lower extremity defects: anatomic considerations. Surg Clin North Am. 1974;54:1337 1354. 22. Shepherd LE, Costigan WM, Gardocki RJ , et al. Local or

  6. Supplementary safety system corrosion studies

    SciTech Connect

    Anderson, M.H.; Wiersma, B.J.

    1991-05-21

    This memorandum presents experimental data from electrochemical and immersion tests to support the continued use of two sections of nonconforming steel in the Supplementary Safety System. The Reactor Corrosion Mitigation Committee met on May 16, 1991 to evaluate materials that had been installed in the SSS. The materials lacked complete Corrosion Evaluation (CE) and/or Certified Mill Test Reports and had been installed during recent modifications (Project S-4332). Items that lacked proper documentation included AISI Type 304 stainless steel (304) instrument tubing (0.375'' OD) associated with the pressure transmitters and a two-foot section of 304 pipe located on the far side of the system downstream of the pneumatic valves. Cyclic potentiodynamic polarization scans were performed on sensitized and solution-annealed 304 samples in as-mixed and acidified Gd(NO{sub 3}){sub 3}, or ink'', solutions at room temperature to determine the susceptibility of 304 to localized corrosion in this environment. No localized attack was observed on the solution annealed or sensitized 304 in the Gd(NO{sub 3}){sub 3} solution. These tests revealed no significant differences in the behavior of the sensitized and solution-annealed 304 in gadolinium nitrate solution. Therefore, localized corrosion of the nonconforming components is not anticipated, and the performance of the nonconforming components should not differ from that of corrosion evaluated and certified materials. Previous studies have shown that AISI Type 304L stainless steel (304L) did not pit during a three-month exposure in gadolinium nitrate solutions of pH 2 or 5. These combined results support the continued use of the nonconforming steels until replacement can be made at the next scheduled long shut-down.

  7. Supplementary safety system corrosion studies

    SciTech Connect

    Anderson, M.H.; Wiersma, B.J.

    1991-05-21

    This memorandum presents experimental data from electrochemical and immersion tests to support the continued use of two sections of nonconforming steel in the Supplementary Safety System. The Reactor Corrosion Mitigation Committee met on May 16, 1991 to evaluate materials that had been installed in the SSS. The materials lacked complete Corrosion Evaluation (CE) and/or Certified Mill Test Reports and had been installed during recent modifications (Project S-4332). Items that lacked proper documentation included AISI Type 304 stainless steel (304) instrument tubing (0.375`` OD) associated with the pressure transmitters and a two-foot section of 304 pipe located on the far side of the system downstream of the pneumatic valves. Cyclic potentiodynamic polarization scans were performed on sensitized and solution-annealed 304 samples in as-mixed and acidified Gd(NO{sub 3}){sub 3}, or ``ink``, solutions at room temperature to determine the susceptibility of 304 to localized corrosion in this environment. No localized attack was observed on the solution annealed or sensitized 304 in the Gd(NO{sub 3}){sub 3} solution. These tests revealed no significant differences in the behavior of the sensitized and solution-annealed 304 in gadolinium nitrate solution. Therefore, localized corrosion of the nonconforming components is not anticipated, and the performance of the nonconforming components should not differ from that of corrosion evaluated and certified materials. Previous studies have shown that AISI Type 304L stainless steel (304L) did not pit during a three-month exposure in gadolinium nitrate solutions of pH 2 or 5. These combined results support the continued use of the nonconforming steels until replacement can be made at the next scheduled long shut-down.

  8. Blasting and Passivation Treatments for ASTM F139 Stainless Steel for Biomedical Applications: Effects on Surface Roughness, Hardening, and Localized Corrosion

    NASA Astrophysics Data System (ADS)

    Barboza, Adriana L. Lemos; Kang, Kyung Won; Bonetto, Rita D.; Llorente, Carlos L.; Bilmes, Pablo D.; Gervasi, Claudio A.

    2015-01-01

    Due to the combination of good biofunctionality and biocompatibility at low cost, AISI 316 low carbon vacuum melting (LVM) stainless steel, as considered in ASTM F139 standard, is often the first choice for medical implants, particularly for use in orthopedic surgery. Proper surface finish must be provided to ensure adequate interactions of the alloy with human body tissues that in turn allows the material to deliver the desired performance. Preliminary studies performed in our laboratory on AISI 316LVM stainless steel surfaces modified by glass bead blasting (from industrial supplier) followed by different nitric acid passivation conditions disclosed the necessity to extend parameters of the surface treatments and to further consider roughness, pitting corrosion resistance, and surface and subsurface hardening measurements, all in one, as the most effective characterization strategy. This was the approach adopted in the present work. Roughness assessment was performed by means of amplitude parameters, functional parameters, and an estimator of the fractal dimension that characterizes surface topography. We clearly demonstrate that the blasting treatment should be carried out under controlled conditions in order to obtain similar surface and subsurface properties. Otherwise, a variation in one of the parameters could modify the surface properties, exerting a profound impact on its application as biomaterial. A passivation step is necessary to offset the detrimental effect of blasting on pitting corrosion resistance.

  9. Corrosion protection of reusable surgical instruments.

    PubMed

    Shah, Sadiq; Bernardo, Mildred

    2002-01-01

    To understand the corrosion properties of surgical scissors, 416 stainless steel disks and custom electrodes were used as simulated surfaces under various conditions. These simulated surfaces were exposed to tap water and 400-ppm synthetic hard water as Ca2CO3 under different conditions. The samples were evaluated by various techniques for corrosion potential and the impact of environmental conditions on the integrity of the passive film. The electrodes were used to monitor the corrosion behavior by potentiodynamic polarization technique in water both in the presence and absence of a cleaning product. The surface topography of the 416 stainless steel disks was characterized by visual observations and scanning electron microscopy (SEM), and the surface chemistry of the passive film on the surface of the scissors was characterized by x-ray photoelectron spectroscopy (XPS). The results suggest that surgical instruments made from 416 stainless steel are not susceptible to uniform corrosion; however, they do undergo localized corrosion. The use of suitable cleaning products can offer protection against localized corrosion during the cleaning step. More importantly, the use of potentiodynamic polarization techniques allowed for a quick and convenient approach to evaluate the corrosion properties of surgical instruments under a variety of simulated-use environmental conditions.

  10. Effect of residual stress relaxation by means of local rapid induction heating on stress corrosion cracking behavior and electrochemical characterization of welded Ti-6Al-4V alloy under slow strain rate test

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Tang, Shawei; Liu, Guangyi; Sun, Yue; Hu, Jin

    2017-05-01

    In this study, a welded Ti-6Al-4V alloy was treated by means of local rapid induction heating in order to relax the residual stress existed in the weldment. The welded samples were heat treated at the different temperatures. The stress corrosion cracking behavior and electrochemical characterization of the as-welded samples before and after the post weld heat treatment as a function of residual stress were investigated. Electrochemical impedance spectroscopy measurements of the samples under slow strain rate test were performed in a LiCl-methanol solution. The results demonstrated that the residual stress in the as-welded sample was dramatically reduced after the post weld heat treatment, and the residual stress decreased with the increase in the heat treatment temperature. The stress corrosion cracking susceptibility and electrochemical activity of the as-welded sample were significantly reduced after the heat treatment due to the relaxation of the residual stress, which gradually decreased with the decreasing value of the residual stress distributed in the heat treated samples.

  11. Prediction of Corrosion of Advanced Materials and Fabricated Components

    SciTech Connect

    A. Anderko; G. Engelhardt; M.M. Lencka; M.A. Jakab; G. Tormoen; N. Sridhar

    2007-09-29

    The goal of this project is to provide materials engineers, chemical engineers and plant operators with a software tool that will enable them to predict localized corrosion of process equipment including fabricated components as well as base alloys. For design and revamp purposes, the software predicts the occurrence of localized corrosion as a function of environment chemistry and assists the user in selecting the optimum alloy for a given environment. For the operation of existing plants, the software enables the users to predict the remaining life of equipment and help in scheduling maintenance activities. This project combined fundamental understanding of mechanisms of corrosion with focused experimental results to predict the corrosion of advanced, base or fabricated, alloys in real-world environments encountered in the chemical industry. At the heart of this approach is the development of models that predict the fundamental parameters that control the occurrence of localized corrosion as a function of environmental conditions and alloy composition. The fundamental parameters that dictate the occurrence of localized corrosion are the corrosion and repassivation potentials. The program team, OLI Systems and Southwest Research Institute, has developed theoretical models for these parameters. These theoretical models have been applied to predict the occurrence of localized corrosion of base materials and heat-treated components in a variety of environments containing aggressive and non-aggressive species. As a result of this project, a comprehensive model has been established and extensively verified for predicting the occurrence of localized corrosion as a function of environment chemistry and temperature by calculating the corrosion and repassivation potentials.To support and calibrate the model, an experimental database has been developed to elucidate (1) the effects of various inhibiting species as well as aggressive species on localized corrosion of nickel

  12. A histone arginine methylation localizes to nucleosomes in satellite II and III DNA sequences in the human genome.

    PubMed

    Capurso, Daniel; Xiong, Hao; Segal, Mark R

    2012-11-15

    Applying supervised learning/classification techniques to epigenomic data may reveal properties that differentiate histone modifications. Previous analyses sought to classify nucleosomes containing histone H2A/H4 arginine 3 symmetric dimethylation (H2A/H4R3me2s) or H2A.Z using human CD4+ T-cell chromatin immunoprecipitation sequencing (ChIP-Seq) data. However, these efforts only achieved modest accuracy with limited biological interpretation. Here, we investigate the impact of using appropriate data pre-processing -deduplication, normalization, and position- (peak-) finding to identify stable nucleosome positions - in conjunction with advanced classification algorithms, notably discriminatory motif feature selection and random forests. Performance assessments are based on accuracy and interpretative yield. We achieved dramatically improved accuracy using histone modification features (99.0%; previous attempts, 68.3%) and DNA sequence features (94.1%; previous attempts, <60%). Furthermore, the algorithms elicited interpretable features that withstand permutation testing, including: the histone modifications H4K20me3 and H3K9me3, which are components of heterochromatin; and the motif TCCATT, which is part of the consensus sequence of satellite II and III DNA. Downstream analysis demonstrates that satellite II and III DNA in the human genome is occupied by stable nucleosomes containing H2A/H4R3me2s, H4K20me3, and/or H3K9me3, but not 18 other histone methylations. These results are consistent with the recent biochemical finding that H4R3me2s provides a binding site for the DNA methyltransferase (Dnmt3a) that methylates satellite II and III DNA. Classification algorithms applied to appropriately pre-processed ChIP-Seq data can accurately discriminate between histone modifications. Algorithms that facilitate interpretation, such as discriminatory motif feature selection, have the added potential to impart information about underlying biological mechanism.

  13. Microbial Corrosion in Linepipe Steel Under the Influence of a Sulfate-Reducing Consortium Isolated from an Oil Field

    NASA Astrophysics Data System (ADS)

    AlAbbas, Faisal M.; Williamson, Charles; Bhola, Shaily M.; Spear, John R.; Olson, David L.; Mishra, Brajendra; Kakpovbia, Anthony E.

    2013-11-01

    This work investigates microbiologically influenced corrosion of API 5L X52 linepipe steel by a sulfate-reducing bacteria (SRB) consortium. The SRB consortium used in this study was cultivated from a sour oil well in Louisiana, USA. 16S rRNA gene sequence analysis indicated that the mixed bacterial consortium contained three phylotypes: members of Proteobacteria ( Desulfomicrobium sp.), Firmicutes ( Clostridium sp.), and Bacteroidetes ( Anaerophaga sp.). The biofilm and the pits that developed with time were characterized using field emission scanning electron microscopy (FE-SEM). In addition, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) and open circuit potential (OCP) were used to analyze the corrosion behavior. Through circuit modeling, EIS results were used to interpret the physicoelectric interactions between the electrode, biofilm and solution interfaces. The results confirmed that extensive localized corrosion activity of SRB is due to a formed biofilm in conjunction with a porous iron sulfide layer on the metal surface. X-ray diffraction (XRD) revealed semiconductive corrosion products predominantly composed of a mixture of siderite (FeCO3), iron sulfide (Fe x S y ), and iron (III) oxide-hydroxide (FeOOH) constituents in the corrosion products for the system exposed to the SRB consortium.

  14. Stress corrosion cracking of stainless steels

    NASA Astrophysics Data System (ADS)

    Hehemann, R. F.

    1985-11-01

    The similarities and differences in the stress corrosion cracking response of ferritic and austenitic stainless steels in chloride solutions will be examined. Both classes of materials exhibit a cracking potential: similar transient response (to loading) of the potential in open circuit tests or the current in potentiostatic tests and similar enrichment of chromium and depletion of iron in the film associated with localized corrosion processes. The ferritic steels are more resistant to localized corrosion than are the austenitic steels, which is responsible for the difference in the influence of prior thermal and mechanical history on cracking susceptibility of the two types of steel. Similarities in the fractography of stress corrosion cracks and those produced by brittle delayed failure during cathodic charging of the ferritic steels indicate that hydrogen embrittlement is involved in the failure process.

  15. 40 CFR Appendix III to Part 310 - Form: Application for Reimbursement to Local Governments for Emergency Response to Hazardous...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the applicant or other unit of local government. RC Utilities RC1: Utilities—for power, water... durable equipment declared a total loss as a result of contamination during the responseEQ2: Rents—for...

  16. Carbon-ion radiotherapy for locally advanced or unfavorably located choroidal melanoma: A Phase I/II dose-escalation study

    SciTech Connect

    Tsuji, Hiroshi . E-mail: h_tsuji@nirs.go.jp; Ishikawa, Hitoshi; Yanagi, Takeshi; Hirasawa, Naoki; Kamada, Tadashi; Mizoe, Jun-Etsu; Kanai, Tatsuaki; Tsujii, Hirohiko; Ohnishi, Yoshitaka

    2007-03-01

    Purpose: To evaluate the applicability of carbon ion beams for the treatment of choroidal melanoma with regard to normal tissue morbidity and local tumor control. Methods and Materials: Between January 2001 and February 2006, 59 patients with locally advanced or unfavorably located choroidal melanoma were enrolled in a Phase I/II clinical trial of carbon-ion radiotherapy at the National Institute of Radiologic Sciences. The primary endpoint of this study was normal tissue morbidity, and secondary endpoints were local tumor control and patient survival. Of the 59 subjects enrolled, 57 were followed >6 months and analyzed. Results: Twenty-three patients (40%) developed neovascular glaucoma, and three underwent enucleation for eye pain due to elevated intraocular pressure. Incidence of neovascular glaucoma was dependent on tumor size and site. Five patients had died at analysis, three of distant metastasis and two of concurrent disease. All but one patient, who developed marginal recurrence, were controlled locally. Six patients developed distant metastasis, five in the liver and one in the lung. Three-year overall survival, disease-free survival, and local control rates were 88.2%, 84.8%, and 97.4%, respectively. No apparent dose-response relationship was observed in either tumor control or normal tissue morbidity at the dose range applied. Conclusion: Carbon-ion radiotherapy can be applied to choroidal melanoma with an acceptable morbidity and sufficient antitumor effect, even with tumors of unfavorable size or site.

  17. Microbiologically Influenced Corrosion of Pilings

    DTIC Science & Technology

    2014-03-04

    localised attack including pitting, enhanced erosion corrosion, enhanced galvanic corrosion, stress corrosion cracking, and hydrogen embrittlement of CS...proJiKx localisv.J attack incluJmi; pittm;;, ciilianci-J viosion corrosion, enhanced galvanic corrosion, stress corrosion cracking, and hydrogen

  18. Biochemical Contributions to Corrosion of Carbon Steel and Alloy 22 in a Continual Flow System

    SciTech Connect

    Horn, J.; Martin, S.; Masterson, B.; Lian, T.

    1998-12-03

    Microbiologically influenced corrosion (MIC) may decrease the functional lifetime of nuclear waste packaging materials in the potential geologic repository at Yucca Mountain (YM), Nevada. Biochemical contributions to corrosion of package materials are being determined in reactors containing crushed repository-site rock with the endogenous microbial community, and candidate waste package materials. These systems are being continually supplied with simulated ground water. Periodically, bulk chemistries are analyzed on the system outflow, and surfacial chemistries are assessed on withdrawn material coupons. Both Fe and Mn dissolved from C1020 coupons under conditions that included the presence of YM microorganisms. Insoluble corrosion products remained in a reduced state at the coupon surface, indicating at least a localized anoxic condition; soluble reduced Mn and Fe were also detected in solution, while precipitated and spalled products were oxidized. Alloy 22 surfaces showed a layer of chrome oxide, almost certainly in the Cr(III) oxidation state, on microcosm-exposed coupons, while no soluble chrome was detected in solution. The results of these studies will be compared to identical testing on systems containing sterilized rock to generate, and ultimately predict, microbial contributions to waste package corrosion chemistries.

  19. Corrosion of surface defects in fine wires.

    PubMed

    Rentler, R M; Greene, N D

    1975-11-01

    Defects were observed on the surfaces of various fine diameter wires commonly used in biomedical applications. These surface irregularities were viewed at high magnifications using a scanning electron microscope which has a much greater depth of field than normal light microscopy. Defects include scratches, pits, and crevices, which are the result of commercial wire drawing practices. Corrosion test results show that imperfections can serve as sites for localized corrosion attack which could lead to premature failures.

  20. Metallized coatings for pressure vessel corrosion

    SciTech Connect

    Hankirk, M. ); Hansen, D.S. )

    1994-09-01

    Metallized coatings have been successful for many years in providing sacrificial protection to pressure vessels in high-temperature applications in which they are susceptible to localized corrosion, hydrogen blistering, erosion, and pitting. In addition, when corrosion allowances have decreased or have been eliminated after many years of service, metallized coatings can be used to restore the allowances and extend the life of the equipment.

  1. 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.

  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. Combination of Iodine-125 brachytherapy and chemotherapy for locally recurrent stage III non-small cell lung cancer after concurrent chemoradiotherapy.

    PubMed

    Yu, Xiaojuan; Li, Jin; Zhong, Xiaoming; He, Jingdong

    2015-10-06

    Locally recurrent non-small cell lung cancer (NSCLC) poses a great challenge to physicians. This study aimed to explore the efficacy and safety of the combination of brachytherapy and docetaxel and cisplatin for the treatment of locally recurrent stage III NSCLC. Fifty two patients with locally recurrent stage III NSCLC after concurrent chemoradiotherapy were randomly divided into two groups (n = 26). The patients in experimental group were treated with implantation of radioactive (125)I seeds and DP regimen (docetaxel 60 mg/m(2)/cisplatin 75 mg/m(2)). Patients in control group received DP chemotherapy. The local control rate (LCR), progression-free survival (PFS), and overall response rate (ORR) were defined according to the Response Evaluation Criteria in Solid Tumors (RECIST). With a median follow-up time of 11 months, PFS and LCR was 8 months (95 % CI: 6.99-9.01 months) vs. 5.5 months (95 % CI: 4.43-6.57 months) (P < 0.05) and 10 months (95 % CI: 8.72-11.28 months) vs. 6.2 months (95 % CI: 5.27-7.13 months) (P < 0.05) in the experimental and control groups, respectively. The ORR did not differ between treatment groups and was noted to be 69.2 % and 57.7 %, respectively (P >0.05). There was no occurrence of severe complications in experimental and control groups. The combination of (125)I brachytherapy and second-line chemotherapy is superior to chemotherapy alone and is an effective and safe therapy for this disease. ChiCTR-IOR-15006560.

  4. Defining the Role of Neoadjuvant Chemotherapy Followed by Surgery in Locally Advanced Cancer Cervix: A Meta-analysis of Phase III Trials.

    PubMed

    Osman, Mohammed A

    2016-10-01

    This meta-analysis was performed to compare the outcomes between NACT-S and RT for locally advanced cancer cervix. The primary end points were survival benefits. The data sources for the search included medline, national library of medicine, and the embase search engines. Inclusion criteria included studies published between 2000 and 2012, and FIGO stages IB2 to IVA. Studies had to be properly randomized, prospective, or retrospective and only phase III. Further, the studies had to be with two arms, including one arm for neoadjuvant chemotherapy then-surgery (NACT-S), and the other arm for radiotherapy (RT). Data were collected from 1171 patients enrolled in seven phase III trials. The 5-year PFS (progression-free survival) for NACT-S and RT were 62 and 45.5 %, respectively. The 5-year OS for NACT-S and RT were 66 and 49 %, respectively. NACT-S was associated with better late toxicities compared to RT. NACT-S is a reasonable treatment option for locally advanced cancer cervix. It achieved better results than RT, especially for stages from IB2 to IIB.

  5. Automated Corrosion Detection Program

    DTIC Science & Technology

    2001-10-01

    color. 14. ABSTRACT An evaluation of several hidden corrosion-detection technologies was performed using a probability of detection ( POD ) method for...for improved corrosion management maintenance philosophies. 15. SUBJECT TERMS Corrosion, NDE, probability of detection ( POD ), KC-135, material loss...Size ...............................30 11 POD Curve

  6. Corrosion: ASM metals handbook

    SciTech Connect

    Not Available

    1987-01-01

    The handbook covers forms of corrosion, testing and evaluation, corrosion-resistant design, and various protection methods. 20 sections covering specific metals and alloys, heat treatments, protective coatings, anodic and cathodic protection, and design considerations. A final section discusses corrosion problems in 20 major industries, as well as the prevention and protection methods used.

  7. Property Accounting for Local and State School Systems. State Educational Records and Reports Series--Handbook III.

    ERIC Educational Resources Information Center

    Reason, Paul L.; Tankard, George G., Jr.

    This handbook serves as a basic guide to property accounting for local and state school systems in the U.S. Information and guidelines are presented regarding--(1) classification of property accounts, (2) definitions of property accounts, (3) measures of school property, (4) supplies and equipment, (5) individual property records, and (6) summary…

  8. The local treatment modalities in FIGO stage I-II small-cell carcinoma of the cervix are determined by disease stage and lymph node status.

    PubMed

    Zhou, Juan; Yang, Hong-Yi; Wu, San-Gang; He, Zhen-Yu; Lin, Huan-Xin; Sun, Jia-Yuan; Li, Qun; Guo, Zhan-Wen

    2016-06-01

    The purpose of this study was to identify the optimal local treatment modalities for International Federation of Gynecology and Obstetrics (FIGO) stage I-II small-cell carcinoma of the cervix (SCCC), including cancer-directed surgery (CDS) and/or radiotherapy (RT). The Surveillance Epidemiology and End Results (SEER) database was used to identify SCCC patients from 1988 to 2012, and analyzed using Kaplan-Meier survival and Cox regression proportional hazard methods to determine factors significant for cause-specific survival (CSS) and overall (OS). A total of 208 patients of SCCC were enrolled. The median follow-up time was 31 months. Fifty-eight (27.9%) patients were treated with primary CDS, 88 (42.3%) patients underwent CDS combined with RT, and 62 (29.8%) patients were treated with primary RT. Univariate and multivariate analyses showed that local treatment modalities were independent prognostic factors for CSS and OS. Patients who had undergone CDS had better CSS and OS, compared with patients who had been treated with combined CDS and RT or RT alone. The 5-year CSS and OS of entire group was 49.8% and 46.4%, respectively. The 5-year CSS in the groups of patients receiving CDS, CDS combined with RT, and RT alone were 67.9%, 49.7%, and 32.6%, respectively (P < 0.001). The 5-year OS in patients treated with CDS, CDS combined with RT, and RT alone were 64.9%, 46.2%, and 28.8% (P < 0.001). Primary surgery was associated with improved CSS and OS for FIGO stage I and lymph node negative disease. Primary surgery is the most effective local treatment for FIGO stage I-II SCCC, as adjuvant RT or radical RT does not improve survival compared to radical surgery, especially in patients with FIGO stage I and lymph node negative disease.

  9. Marine and offshore corrosion

    SciTech Connect

    Chandler, K.A.

    1985-01-01

    Until recently marine corrosion technology has been preoccupied with the corrosion of ships. Within the last ten years, however, the rapid expansion of oil and gas exploration has changed the course of corrosion research as well as the market for corrosion services and products. So complete has been the change that a new approach, dealing with ships, structures, and plant has been taken in this book. This introduction to the control of corrosion in marine environments will serve as a reference on topics ranging from coating systems to metallurgical considerations in the design of ships, offshore structure, plant and pipelines.

  10. 2nd ESMO Consensus Conference in Lung Cancer: locally advanced stage III non-small-cell lung cancer.

    PubMed

    Eberhardt, W E E; De Ruysscher, D; Weder, W; Le Péchoux, C; De Leyn, P; Hoffmann, H; Westeel, V; Stahel, R; Felip, E; Peters, S

    2015-08-01

    To complement the existing treatment guidelines for all tumour types, ESMO organises consensus conferences to focus on specific issues in each type of tumour. The 2nd ESMO Consensus Conference on Lung Cancer was held on 11-12 May 2013 in Lugano. A total of 35 experts met to address several questions on non-small-cell lung cancer (NSCLC) in each of four areas: pathology and molecular biomarkers, first-line/second and further lines of treatment in advanced disease, early-stage disease and locally advanced disease. For each question, recommendations were made including reference to the grade of recommendation and level of evidence. This consensus paper focuses on locally advanced disease.

  11. Local Environment of Terbium(III) Ions in Layered Nanocrystalline Zirconium(IV) Phosphonate-Phosphate Ion Exchange Materials.

    PubMed

    Terban, Maxwell W; Shi, Chenyang; Silbernagel, Rita; Clearfield, Abraham; Billinge, Simon J L

    2017-08-07

    The structures of Zr(IV) phosphonate-phosphate based, unconventional metal organic framework materials have been determined using atomic pair distribution function analysis of high energy, X-ray total scattering diffraction data. They are found to form as nanocrystalline layers of Zr phosphate, similar to the bulk, but with a high degree of interlayer disorder and intermediate intralayer order extending around 5 nm. These materials are of interest for their high selectivity for 3+ lanthanide ions. To investigate the mechanism of the selectivity, we utilize difference pair distribution function analysis to extract the local structural environment of Tb(3+) ions loaded into the framework. The ions are found to sit between the layers in a manner resembling the local environment of Tb in Scheelite-type terbium phosphate. By mapping this local structure onto that of the refined structure for zirconium-phenyl-phosphonate, we show how dangling oxygens from the phosphate groups, acting like nose hairs, are able to reorient to provide a friendly intercalation environment for the Tb(3+) ions.

  12. Aggressive Behavior in Silent Subtype III Pituitary Adenomas May Depend on Suppression of Local Immune Response: A Whole Transcriptome Analysis.

    PubMed

    Richardson, Timothy E; Shen, Zhong-Jian; Kanchwala, Mohammed; Xing, Chao; Filatenkov, Alexander; Shang, Ping; Barnett, Samuel; Abedin, Zahidur; Malter, James S; Raisanen, Jack M; Burns, Dennis K; White, Charles L; Hatanpaa, Kimmo J

    2017-10-01

    Silent subtype III pituitary adenomas (SS-3) are clinically nonfunctional adenomas that are more aggressive in terms of invasion and risk of recurrence than their conventional null cell counterparts. We previously showed that these tumors can be distinguished by immunohistochemistry based on the identification of a markedly enlarged and fragmented Golgi apparatus. To understand the molecular correlates of differential aggressiveness, we performed whole transcriptome sequencing (RNAseq) on 4 SS-3 and 4 conventional null cell adenomas. The genes that were highly upregulated in all the SS-3 adenomas included 2 secreted proteins involved in the suppression of T-lymphocyte activity, i.e., ARG2 (multiple testing adjusted padj = 1.5 × 10-3) and SEMA3A (padj = 3.3 × 10-3). Highly downregulated genes in all the SS-3 adenomas included HLA-B (padj = 3.3 × 10-6), suggesting reduced antigen presentation by the adenoma to cytotoxic T-cells. Quantitative RT-PCR of these genes performed on the adenoma samples supported the RNAseq results. We also found a relative decrease in the overall concentration of T-lymphocytes in the SS-3 tumors. These results suggest that SS-3 adenomas actively suppress the immune system and raise the possibility that they may be treatable with immune checkpoint inhibitors or nonspecific cancer immunotherapies. © 2017 American Association of Neuropathologists, Inc. All rights reserved.

  13. Long Term Corrosion Potential and Corrosion Rate of Creviced Alloy 22 in Chloride Plus Nitrate Brines

    SciTech Connect

    Evans, K J; Stuart, M L; Etien, R A; Hust, G A; Estill, J C; Rebak, R B

    2005-11-05

    Alloy 22 is a nickel base alloy highly resistant to all forms of corrosion. In conditions where tight crevices exist in hot chloride containing solutions and at anodic potentials, Alloy 22 may suffer crevice corrosion, a form of localized attack. The occurrence (or not) of crevice corrosion in a given environment (e.g. salt concentration and temperature), is governed by the values of the critical potential (E{sub crit}) for crevice corrosion and the corrosion potential (E{sub corr}) that the alloy may establish in the studied environment. If E{sub corr} is equal or higher than E{sub crit}, crevice corrosion may be expected. In addition, it is generally accepted that as Alloy 22 becomes passive in a certain environment, its E{sub corr} increases and its corrosion rate (CR) decreases. This paper discusses the evolution of E{sub corr} and corrosion rate (CR) of creviced Alloy 22 specimens in six different mixtures of sodium chloride (NaCl) and potassium nitrate (KNO{sub 3}) at 100 C. The effect of immersion time on the value of E{sub crit} was also determined. Two types of specimens were used, polished as-welded (ASW) and as-welded plus solution heat-treated (ASW+SHT). The latter contained the black annealing oxide film on the surface. Results show that, as the immersion time increases, E{sub corr} increased and the CR decreased. Even for highly concentrated brine solutions at 100 C the CR was < 30 nm/year after more than 250 days immersion. Some of the exposed specimens (mainly the SHT specimens) suffered crevice corrosion at the open circuit potential in the naturally aerated brines. Immersion times of over 250 days did not reduce the resistance of Alloy 22 to localized corrosion.

  14. Local structure and dynamics of III-V semiconductor alloys by high resolution x-ray pair distribution function analysis

    NASA Astrophysics Data System (ADS)

    Jeong, Il-Kyoung

    In semiconductor alloys such as In1-xGaxAs, the energy band gap as well as the lattice parameter can be engineered by changing the concentration, x. Due to these properties, semiconductor alloys have found wide applications in optoelectronic devices. In these alloys, local structure information is of fundamental importance in understanding the physical properties such as band structure. Using the high real-space resolution atomic Pair Distribution Function, we obtained more complete structural information such as bond length, bond length distributions, and far-neighbor distances and distributions. From such experimental information and the Kirkwood model we studied both local static displacements and correlations in the displacements of atoms. The 3-dimensional As and (In,Ga) atom iso-probability surfaces were obtained from the supercell relaxed using the Kirkwood potential. This shows that the As atom displacements are very directional and can be represented as a combination of <100> and <111> displacements. On the contrary, the (In,Ga) atom displacements are more or less isotropic. In addition, the single crystal diffuse scattering calculation of the relaxed supercell shows that the atomic displacements are correlated over longer range along [110] directions although the displacements of As atoms are along <100> and <111> directions. Besides the local static displacements, we studied correlations in thermal atomic motions of atom pairs from the PDF peak width changes as a function of atom pair distance. In the PDF the near-neighbor peaks are sharper than those of far-neighbors due to the correlation in near-neighbor thermal motions. We also determined bond stretching and bond bending force constants of semiconductor compounds by fitting the nearest neighbor and far-neighbor peak widths to the lattice dynamic calculations using the Kirkwood model.

  15. Liposomal doxorubicin in conjunction with reirradiation and local hyperthermia treatment in recurrent breast cancer: a phase I/II trial.

    PubMed

    Kouloulias, Vassilios E; Dardoufas, Costas E; Kouvaris, John R; Gennatas, Costas S; Polyzos, Aris K; Gogas, Helen J; Sandilos, Panagiotis H; Uzunoglu, Nikolaos K; Malas, Elias G; Vlahos, Lambros J

    2002-02-01

    This is the first study to evaluate the tolerability and activity of liposomal doxorubicin (Caelyx; Schering-Plough Pharmaceuticals) < or =60 mg/km(2) in patients with locally recurrent breast cancer, when administered in conjunction with reirradiation and local hyperthermia treatment. Fifteen female patients, who had undergone a radical mastectomy and conventional radiotherapy (60 Gy) in the front chest wall, were entered on a multimodal protocol consisting of initial treatment with radiotherapy and a monthly infusion of liposomal doxorubicin < or =60 mg/m(2) in conjunction with local hyperthermia treatment. All patients received reirradiation up to a total dose of 30.6 Gy (1.8 Gy/fraction, 5 days a week). To evaluate the drug's safety, the first 5 patients initially received a dose of 40 mg/m(2) liposomal doxorubicin, which was then escalated to 60 mg/m(2). The other 10 patients received 60 mg/m(2) for all six cycles of chemotherapy. Hyperthermia (HT) was produced in the region of interest (ROI) using waveguides at a frequency of 433 MHz. The RSS was obtained from the curves representing the change in the ROI's surface with time for each patient, as fitted by linear regression. Linear regression analysis was used to study the relationship between the time interval from liposomal doxorubicin infusion to HT and the RSS. At doses of < or =60 mg/m(2), liposomal doxorubicin was well tolerated, with only mild hematological and nonhematological toxicity. All patients showed an objective measurable response, with 3 patients (20%) demonstrating a clinically complete response. There was a significant correlation between the duration of response and Avg Min T(90) > 44 degrees C (r(s) = 0.917, P < 0.0001) and the Mean[Tmin] (r(s) = 0.909, P < 0.0001). The RSS was significantly correlated with the interval between liposomal doxorubicin infusion and HT, as the smaller the time interval, the greater the clinical benefit (r = 0.76, P = 0.001). The multimodal treatment was

  16. Concurrent Hyperfractionated Radiation Therapy and Chemotherapy in Locally Advanced (Stage III) Non-Small-Cell Lung Cancer: Single Institution Experience With 600 Patients

    SciTech Connect

    Jeremic, Branislav; Milicic, Biljana; Milisavljevic, Slobodan

    2012-03-01

    Purpose: Our institutional experience with the use of hyperfractionated radiation therapy (RT) alone or concurrently with chemotherapy (RT-CHT) in Stage III non-small-cell lung cancer was reviewed. Methods and Materials: Three phase III and two phase II studies included a total of 600 patients. Hyperfractionated RT alone was given to 127 patients, and hyperfractionated RT-CHT was given to 473 patients. RT doses were 64.8 Gy and 69.6 Gy (using 1.2 Gy twice daily) and 67.6 Gy (using 1.3 Gy twice daily). CHT consisted of concurrent administration of carboplatin and etoposide to 409 patients and concurrent administration of carboplatin and paclitaxel to 64 patients. Results: The median survival times were 19 months, 21 months, and 12 months for all, RT-CHT, and RT-only patients, respectively. The survival difference between the RT-CHT and RT group was significant (p < 0.0001). Four-year rates of local progression-free survival (LPFS) and distant metastasis-free survival (DMFS) were 29% and 35%, respectively, for the entire group. The RT-CHT group had significantly better LPFS rates than the RT group (31% for the RT-CHT group vs. 16% for the RT group; p = 0.0015) but not DMFS rates (36% for the RT-CHT group vs. 36% for the RT group, p = 0.0571). Acute high-grade esophagitis, pneumonitis, and hematological toxicities were seen most frequently and in 11%, 9%, and 12% of patients, respectively. Late high-grade esophageal and bronchopulmonary toxicity were each seen in 6% of patients. Conclusions: Compared to the majority of existing phase II and III studies, this study reconfirmed the excellent results achieved with concurrent RT-CHT, including low toxicity. Concurrent RT-CHT results in survival benefit primarily by increasing LPFS, not DMFS.

  17. Improved Survival in Patients With Stage III-IV Head and Neck Cancer Treated With Radiotherapy as Primary Local Treatment Modality

    SciTech Connect

    Rusthoven, Kyle E.; Raben, David; Chen Changhu

    2008-10-01

    Purpose: To evaluate the overall and cause-specific survival in patients with Stage III-IVb head and neck squamous cell carcinoma treated with radiotherapy (RT) as the primary local treatment modality. Methods and Materials: The survival of patients with American Joint Committee on Cancer Stage III-IVb head and neck squamous cell carcinoma treated with primary RT was queried using the Surveillance, Epidemiology and End Results database. The effect of the year of treatment on overall and cause-specific survival was analyzed as a categorical and continuous variable. The patterns of care for these patients were also evaluated. Results: Between 1988 and 2004, 6,759 patients were identified. Survival was significantly improved in patients treated more recently. When analyzed as a continuous variable, each year was associated with a 3% and 4.1% reduction in the relative risk of overall and cause-specific mortality, respectively (p < 0.0001). Patients treated after 1998 had a 7.6% and 6.1% absolute improvement in overall and cause-specific survival, respectively, compared with patients treated before 1998 (overall survival, hazard ratio, 0.81; cause-specific survival, hazard ratio, 0.77; p < 0.0001). This benefit in survival was limited to tumors of the oral cavity, oropharynx, and hypopharynx. The use of RT increased among patients treated more recently. This shift in patterns of care was most pronounced for tumors of the larynx and hypopharynx. Conclusions: The overall and cause-specific survival of patients with Stage III-IVb head and neck squamous cell carcinoma treated with primary RT has improved with time. The improvement is consistent with that observed in a large meta-analysis of randomized patients treated with concurrent chemoradiotherapy.

  18. Engineering Task Plan for the 241-AN-105 Multi-Function Corrosion Monitoring System

    SciTech Connect

    EDGEMON, G.L.

    1999-08-25

    This Engineering Task Plan (ETP) describes the activities associated with the installation of the corrosion probe assembly into riser WST-RISER-016 (formerly 15B) of tank 241-AN-105. The corrosion monitoring system utilizes the technique of electrochemical noise (EN) for monitoring waste tank corrosion. Typically, EN consists of low frequency (4 Hz) and small amplitude signals that are spontaneously generated by electrochemical reactions occurring at corroding or other surfaces. EN analysis is well suited for monitoring and identifying the onset of localized corrosion, and for measuring uniform corrosion rates. A typical EN based corrosion-monitoring system measures instantaneous fluctuations in corrosion current and potential between three nominally identical electrodes of the material of interest immersed in the environment of interest. Time-dependent fluctuations in corrosion current are described by electrochemical current noise, and time-dependent fluctuations of corrosion potential are described by electrochemical noise. The corrosion monitoring system is designed to detect the onset of localized corrosion phenomena if tank conditions should change to allow these phenomena to occur. In addition to the EN technique, the system also facilitates the use of the Linear Polarization Resistance (LPR) technique to collect uniform corrosion rate information. LPR measures the linearity at the origin of the polarization curve for overvoltages up to a few millivolts away from the rest potential or natural corrosion potential. The slope of the current vs. voltage plot gives information on uniform corrosion rates.

  19. The impact of local control in the treatment of type II/III pleuropulmonary blastoma. Experience of the Cooperative Weichteilsarkom Studiengruppe (CWS).

    PubMed

    Sparber-Sauer, Monika; Seitz, Guido; Kirsch, Sylvia; Vokuhl, Christian; Leuschner, Ivo; Dantonello, Tobias M; Scheer, Monika; von Kalle, Thekla; Ljungman, Gustaf; Bielack, Stefan S; Klingebiel, Thomas; Fuchs, Joerg; Koscielniak, Ewa

    2017-02-01

    This study aims at examining the potential survival benefits of primary versus secondary surgery in the management of children diagnosed with pleuropulmonary blastoma (PPB) type II/III. Disease characteristics, treatment, and survival of 29 children with localized PPB type II/III, treated in six prospective Cooperative Weichteilsarkom Studiengruppe (CWS) trials, were reviewed retrospectively. Five year event free survival (EFS) and overall survival (OS) of children treated according to CWS protocols was 72%. Patients with tumors ≤10 cm had a 5 year OS of 91% versus 57% in patients with tumors >10 cm (P = 0.025). Five year OS of patients with macroscopically incomplete upfront resections was 44% as opposed to 68% in patients with delayed/secondary microscopically or macroscopically complete resection after an initial biopsy (P = 0.476). Ten patients died of disease, one patient died of second malignancy. Tumor size and complete tumor resection at any time were significant prognostic factors (P = 0.025/0.003) for EFS. EFS for microscopically complete, microscopically incomplete, and macroscopically incomplete resection at any time was 91%, 90%, and 25%, respectively (P = 0.01). Primary or secondary microscopically/macroscopically complete tumor resections in combination with chemotherapy correlates with long term survival in children with PPB. J. Surg. Oncol. 2017;115:164-172. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Corrosion Product Film-Induced Stress Facilitates Stress Corrosion Cracking

    PubMed Central

    Wang, Wenwen; Zhang, Zhiliang; Ren, Xuechong; Guan, Yongjun; Su, Yanjing

    2015-01-01

    Finite element analyses were conducted to clarify the role of corrosion product films (CPFs) in stress corrosion cracking (SCC). Flat and U-shaped edge-notched specimens were investigated in terms of the CPF-induced stress in the metallic substrate and the stress in the CPF. For a U-shaped edge-notched specimen, the stress field in front of the notch tip is affected by the Young’s modulus of the CPF and the CPF thickness and notch geometry. The CPF-induced tensile stress in the metallic substrate is superimposed on the applied load to increase the crack tip strain and facilitate localized plasticity deformation. In addition, the stress in the CPF surface contributes to the rupture of the CPFs. The results provide physical insights into the role of CPFs in SCC. PMID:26066367

  1. GASTRICHIP: D2 resection and hyperthermic intraperitoneal chemotherapy in locally advanced gastric carcinoma: a randomized and multicenter phase III study

    PubMed Central

    2014-01-01

    Background In Europe, gastric cancer remains diagnosed at advanced stage (serosal and/or lymph node involvement). Despite curative management combining perioperative systemic chemotherapy and gastrectomy with D1-D2 lymph node dissection, 5-year survival rates of T3 and/or N + patients remain under 30%. More than 50% of recurrences are peritoneal and/or locoregional. The use of adjuvant hyperthermic intraperitoneal chemotherapy that eliminates free cancer cells that can be released into peritoneal cavity during the gastrectomy and prevents peritoneal carcinomatosis recurrences, was extensively evaluated by several randomized trials conducted in Asia. Two meta-analysis reported that adjuvant hyperthermic intraperitoneal chemotherapy significantly reduces the peritoneal recurrences and significantly improves the overall survival. As it was previously done for the evaluation of the extension of lymph node dissection, it seems very important to validate on European or caucasian patients the results observed in trials performed in Asia. Methods/design GASTRICHIP is a prospective, open, randomized multicenter phase III clinical study with two arms that aims to evaluate the effects of hyperthermic intraperitoneal chemotherapy with oxaliplatin on patients with gastric cancer involving the serosa and/or lymph node involvement and/or with positive cytology at peritoneal washing, treated with perioperative systemic chemotherapy and D1-D2 curative gastrectomy. Peroperatively, at the end of curative surgery, patients will be randomized after preoperatively written consent has been given for participation. Primary endpoint will be overall survival from the date of surgery to the date of death or to the end of follow-up (5 years). Secondary endpoint will be 3- and 5-year recurrence-free survival, site of recurrence, morbidity, and quality of life. An ancillary study will compare the incidence of positive peritoneal cytology pre- and post-gastrectomy in two arms of the study

  2. ELECTROCHEMICAL NOISE BASED CORROSION MONITORING HANFORD SITE PROGRAM STATUS

    SciTech Connect

    EDGEMON, G.L.

    2005-03-21

    The Hanford Site near Richland, Washington has 177 underground waste tanks that store approximately 253 million liters of radioactive waste from 50 years of plutonium production. Prior to 1995 no online corrosion monitoring systems were in place at Hanford to facilitate the early detection of the onset of localized corrosion should it occur in a waste tank. Because of this, a program was started in 1995 to develop an electrochemical noise (EN) corrosion monitoring system to improve Hanford's corrosion monitoring strategy. Three systems are now installed and operating at Hanford. System design, performance history, data and the results of a recent analysis of tank vapor space data are presented.

  3. Microclimates and Corrosion: A Mathematical Model of Corrosion for Gando AFB, Spain

    DTIC Science & Technology

    1990-09-01

    certain points); pitting (highly localized corrosion resulting in deep penetration at only a few spots); parting (the selective attack of one or more... Exposicion Ambiental(1987-1988). Unpublished Report No. 15. INTA, Madrid, Spain, 1989. 16. Schlotzhauer, D. Sandra and Littell, C. Ramon. SAS System for...LIME: An Environmental Corrosion Severity Classification System: Final Report Part I. Sep 1978 - Dec 1979. Contract F33615-78-C-5224. East Lansing MI

  4. The effects of national health care reform on local businesses--Part III: secondary research questions--discoveries and implications.

    PubMed

    Rotarius, Timothy; Liberman, Aaron; Perez, Bianca

    2012-01-01

    This is the third part of a 3-part examination of what may potentially be expected from the 2010 national health care reform legislation. Political researchers and pundits have speculated endlessly on the many changes mandated by the 2010 national health care reform legislation, styled the Patient Protection and Affordable Care Act. A review and assessment of this legislation at several levels (federal, state, state agency, local region, and individual business leaders) were undertaken. The results of this expanded analysis suggest strongly that nationally members of the business community and their employees will benefit from the legislation early on (years 1 through 3) and then likely will be impacted adversely as the payment mechanisms driving the legislation are tightened by new federal regulations (years 4 onward). As a result of this research, it is surmised that businesses will be immediately impacted by the legislation, with small business owners being the prime beneficiaries of the new legislation, owing to the availability of coverage to approximately 32 million individuals who previously had no access to coverage. In that regard, the soon-to-be newly insured population also will be a prime beneficiary of the legislation as the limitations on chronic illnesses and other preexisting conditions will be reduced or eliminated by the legislation.

  5. Localization landscape theory of disorder in semiconductors. III. Application to carrier transport and recombination in light emitting diodes

    NASA Astrophysics Data System (ADS)

    Li, Chi-Kang; Piccardo, Marco; Lu, Li-Shuo; Mayboroda, Svitlana; Martinelli, Lucio; Peretti, Jacques; Speck, James S.; Weisbuch, Claude; Filoche, Marcel; Wu, Yuh-Renn

    2017-04-01

    This paper introduces a novel method to account for quantum disorder effects into the classical drift-diffusion model of semiconductor transport through the localization landscape theory. Quantum confinement and quantum tunneling in the disordered system change dramatically the energy barriers acting on the perpendicular transport of heterostructures. In addition, they lead to percolative transport through paths of minimal energy in the two-dimensional (2D) landscape of disordered energies of multiple 2D quantum wells. This model solves the carrier dynamics with quantum effects self-consistently and provides a computationally much faster solver when compared with the Schrödinger equation resolution. The theory also provides a good approximation to the density of states for the disordered system over the full range of energies required to account for transport at room temperature. The current-voltage characteristics modeled by three-dimensional simulation of a full nitride-based light emitting diode (LED) structure with compositional material fluctuations closely match the experimental behavior of high-quality blue LEDs. The model allows also a fine analysis of the quantum effects involved in carrier transport through such complex heterostructures. Finally, details of carrier population and recombination in the different quantum wells are given.

  6. 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.

  7. Corrosion, microstructure, and metallography

    SciTech Connect

    Northwood, D.O.; White, W.E.; Vander Voort, G.F.

    1985-01-01

    Of the forty-one papers presented, nearly half of them deal with microstructural aspects of corrosion, corrosion control and corrosion failure analysis. They describe various analytical approaches for studying corrosion and for diagnosing corrosion failure mechanisms. Details include microstructural features of corrosion on a wide range of materials or coatings and in environments ranging from within the human body to outer space. Another series of papers handles microstructure-property relationships and contains reports on hydrogen embrittlement of AISI 316 stainless steel, shell and detail cracking in railroad rails, and the precipitation of martensitic Fe-Ni-W alloys. A third grouping looks at microstructure-fracture relationships. Coverage of advancements in metal-lographic techniques includes the use of microcomputers, applied techniques of inplace analysis, and use of the Tandem Van de Graff accelerator facility.

  8. 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.

  9. A Local Baseline of the Black Hole Mass Scaling Relations for Active Galaxies. III.The MBH - σ Relation

    NASA Astrophysics Data System (ADS)

    Bennert, Vardha N.; Treu, Tommaso; Auger, Matthew W.; Cosens, Maren; Park, Daeseong; Rosen, Rebecca; Harris, Chelsea E.; Malkan, Matthew A.; Woo, Jong-Hak

    2015-08-01

    We create a baseline of the black hole (BH) mass (MBH)—stellar-velocity dispersion (σ) relation for active galaxies, using a sample of 66 local (0.02

  10. Control of metallic corrosion through microbiological route.

    PubMed

    Maruthamuthu, S; Ponmariappan, S; Mohanan, S; Palaniswamy, N; Palaniappan, R; Rengaswamy, N S

    2003-09-01

    Involvement of biofilm or microorganisms in corrosion processes is widely acknowledged. Although majority of the studies on microbiologically induced corrosion (MIC) have concentrated on aerobic/anaerobic bacteria. There are numerous aerobic bacteria, which could hinder the corrosion process. The microbiologically produced exopolymers provide the structural frame work for the biofilm. These polymers combine with dissolved metal ions and form organometallic complexes. Generally heterotrophic bacteria contribute to three major processes: (i) synthesis of polymers (ii) accumulation of reserve materials like poly-beta-hydroxy butrate (iii) production of high molecular weight extracellular polysaccharides. Poly-beta-hydroxy butyrate is a polymer of D(-)beta-hydroxy butrate and has a molecular weight between 60,000 and 2,50,000. Some extracellular polymers also have higher molecular weights. It seems that higher molecular weight polymer acts as biocoating. In the present review, role of biochemistry on corrosion inhibition and possibilities of corrosion inhibition by various microbes are discussed. The role of bacteria on current demand during cathodic protection is also debated. In addition, some of the significant contributions made by CECRI in this promising area are highlighted.

  11. 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.

  12. Galvanic Corrosion Initiatives

    DTIC Science & Technology

    1987-12-01

    tested to indfiqte whether the galvanic corrosion which developed was cosmetic or if it had an effect on ’the mechanical properties wthe * material. fly...properties of each material were determined. The resulting data distinguished the developed corrosion as either being cosmetic or having " " an effect on the...corrosion that occurs is not just cosmetic , but instead has an effect on the mechanical properties of the material. While a galvanic couple may be safe in one

  13. [Evaluation of clinical utility of 123I-MIBG scintigraphy in localization of tumors of sympathetic and adrenomedullary origin--a report of multicenter phase III clinical trials].

    PubMed

    Ishii, K; Kubo, A; Kusakabe, K; Murata, H; Masaki, H; Horiike, S; Hayashi, A; Hara, Y

    2000-01-01

    Phase III clinical study was performed to evaluate clinical utility of 123I-MIBG in the localization of tumors in 48 patients with tumors of sympathetic and adrenomedullary origin, diagnosed or strongly suspected. Sixteen patients had pheochromocytoma, 23 had neuroblastoma, 7 had medullary carcinoma of the thyroid, and 2 had Sipple syndrome. In 3 out of 48 patients, 123I-MIBG scintigraphy was performed twice. The clinical utility of 123I-MIBG was evaluated in 50 cases. Out of 140 lesions, 123I-MIBG scintigraphy demonstrated 51 true positive, 79 true negative, 1 false positive, and 2 false negative. Seven lesions were not evaluable. Sensitivity was 96.2%, Specificity was 98.8%, and Accuracy was 97.7%. An acquisition between 4 hrs and a day after injection was adequate for tumor detection. Neither adverse reactions nor abnormal laboratory findings were noted in relation to 123I-MIBG injections. Our study indicates that 123I-MIBG is a safe and useful radiotracer for visualization and localization of tumors of sympathetic and adrenomedullary origin.

  14. Handbook of corrosion data

    SciTech Connect

    Craig, D.

    1989-01-01

    Each listing includes a general description of the environment, a comment on the corrosion characteristics of various alloys in the environment, a bibliography of recent articles specific to the environment, tables consolidating and comparing corrosion rates at temperatures and concentrations for various alloys, and finally, graphical information. Also included are summaries on the general corrosion characteristics of major metals and alloys. This separate section of the book considers each material group; such as, aluminum, stainless steel, zinc, etc. Additional tables are presented to give the corrosion characteristics of various alloys in hundreds of environments.

  15. Fractionated Boron Neutron Capture Therapy in Locally Recurrent Head and Neck Cancer: A Prospective Phase I/II Trial.

    PubMed

    Wang, Ling-Wei; Chen, Yi-Wei; Ho, Ching-Yin; Hsueh Liu, Yen-Wan; Chou, Fong-In; Liu, Yuan-Hao; Liu, Hong-Ming; Peir, Jinn-Jer; Jiang, Shiang-Huei; Chang, Chi-Wei; Liu, Ching-Sheng; Lin, Ko-Han; Wang, Shyh-Jen; Chu, Pen-Yuan; Lo, Wen-Liang; Kao, Shou-Yen; Yen, Sang-Hue

    2016-05-01

    To investigate the efficacy and safety of fractionated boron neutron capture therapy (BNCT) for recurrent head and neck (H&N) cancer after photon radiation therapy. In this prospective phase 1/2 trial, 2-fraction BNCT with intravenous L-boronophenylalanine (L-BPA, 400 mg/kg) was administered at a 28-day interval. Before each fraction, fluorine-18-labeled-BPA-positron emission tomography was conducted to determine the tumor/normal tissue ratio of an individual tumor. The prescription dose (D80) of 20 Gy-Eq per fraction was selected to cover 80% of the gross tumor volume by using a dose volume histogram, while minimizing the volume of oral mucosa receiving >10 Gy-Eq. Tumor responses and adverse effects were assessed using the Response Evaluation Criteria in Solid Tumors v1.1 and the Common Terminology Criteria for Adverse Events v3.0, respectively. Seventeen patients with a previous cumulative radiation dose of 63-165 Gy were enrolled. All but 2 participants received 2 fractions of BNCT. The median tumor/normal tissue ratio was 3.4 for the first fraction and 2.5 for the second, whereas the median D80 for the first and second fraction was 19.8 and 14.6 Gy-Eq, respectively. After a median follow-up period of 19.7 months (range, 5.2-52 mo), 6 participants exhibited a complete response and 6 exhibited a partial response. Regarding acute toxicity, 5 participants showed grade 3 mucositis and 1 participant showed grade 4 laryngeal edema and carotid hemorrhage. Regarding late toxicity, 2 participants exhibited grade 3 cranial neuropathy. Four of six participants (67%) receiving total D80 > 40 Gy-Eq had a complete response. Two-year overall survival was 47%. Two-year locoregional control was 28%. Our results suggested that 2-fraction BNCT with adaptive dose prescription was effective and safe in locally recurrent H&N cancer. Modifications to our protocol may yield more satisfactory results in the future. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. The Star Formation Histories of Local Group Dwarf Galaxies. III. Characterizing Quenching in Low-mass Galaxies

    NASA Astrophysics Data System (ADS)

    Weisz, Daniel R.; Dolphin, Andrew E.; Skillman, Evan D.; Holtzman, Jon; Gilbert, Karoline M.; Dalcanton, Julianne J.; Williams, Benjamin F.

    2015-05-01

    We explore the quenching of low-mass galaxies (104 ≲ {{M}\\star } ≲ 108 {{M}⊙ }) as a function of lookback time using the star formation histories (SFHs) of 38 Local Group dwarf galaxies. The SFHs were derived by analyzing color-magnitude diagrams of resolved stellar populations in archival Hubble Space Telescope/Wide Field Planetary Camera 2 imaging. We find: (1) lower-mass galaxies quench earlier than higher-mass galaxies; (2) inside of Rvirial there is no correlation between a satellite’s current proximity to a massive host and its quenching epoch; and (3) there are hints of systematic differences in the quenching times of M31 and Milky Way (MW) satellites, although the sample size and uncertainties in the SFHs of M31 dwarfs prohibit definitive conclusions. Combined with results from the literature, we qualitatively consider the redshift evolution (z = 0-1) of the quenched galaxy fraction over ˜7 dex in stellar mass (104 ≲ {{M}\\star } ≲ 1011.5 {{M}⊙ }). The quenched fraction of all galaxies generally increases toward the present, with both the lowest and highest-mass systems exhibiting the largest quenched fractions at all redshifts. In contrast, galaxies between {{M}\\star } ˜ 108-1010 {{M}⊙ } have the lowest quenched fractions. We suggest that such intermediate-mass galaxies are the least efficient at quenching. Finally, we compare our quenching times with predictions for infall times for low-mass galaxies associated with the MW. We find that some of the lowest-mass satellites (e.g., CVn II, Leo IV) may have been quenched before infall, while higher-mass satellites (e.g., Leo I, Fornax) typically quench ˜1-4 Gyr after infall. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Data Archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA constract NAS 5-26555.

  17. The corrosion pattern of reinforcement and its influence on serviceability of reinforced concrete members in chloride environment

    SciTech Connect

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2009-11-15

    This paper deals with two corroded reinforcement concrete beams, which have been stored under sustained load in a chloride environment for 14 and 23 years respectively. The evolution of corrosion pattern of reinforcement and its influence on serviceability are studied. In chloride-induced corrosion process, corrosion cracking affects significantly the corrosion pattern. During the corrosion cracking initiation period, only local pitting corrosion occurs. At early stage of cracking propagation, localized pitting corrosion is still predominant as cracks widths are very small and cracks are not interconnected, but a general corrosion slowly develops as the cracks widen. At late cracking stage, interconnected cracking with wide width develops along large parts of the beam leading to a general corrosion pattern. Macrocells and microcells concepts are used for the interpretation of the results. Mechanical experiments and corrosion simulation tests are performed to clarify the influence of this corrosion pattern evolution on the serviceability of the beams (deflection increase). Experimental results show that, when the corrosion is localized (early cracking stage), the steel-concrete bond loss is the main factor affecting the beams serviceability. The local cross-section loss resulting from pitting attack does not significantly influence the deflection of the beam. When corrosion is generalized (late cracking stage), as the steel-concrete bond is already lost, the generalized steel cross-section reduction becomes the main factor affecting the beams serviceability. But, at this stage, the deflection increase is slower due to the low general corrosion rate.

  18. 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.

  19. Stress Corrosion Cracking of Aluminum Alloys

    DTIC Science & Technology

    2012-09-10

    boundaries into the specimen, attributed to hydrogen embrittlement and anodic dissolution. 15. SUBJECT TERMS Stress Corrosion Cracking (SCC...along grain boundaries into the specimen, attributed to hydrogen embrittlement and anodic dissolution. NAWCADPAX/TR-2012/206 iii Contents...limited to, anodic dissolution[26-31] and hydrogen embrittlement [32-37] of grain boundary. Precipitates are observable on the grain boundaries in

  20. Corrosion Inhibitors for Metals in Naval Environments

    DTIC Science & Technology

    1988-06-15

    filling the void, all involving synthesis of new phthalocyanines that have reactive groups at the positions on the phthalocyanine that are in the void... Phthalocyanine Containing Long-Chain Aliphatic (R) Groups .*.. o... *o..... ..... . .......... 18 5 Nyquist Plot for Steel with and without Co(II) and Fe (III) TC...insoluble phthalocyanines having long-chain alphatic carboxy- lic acid groups attached to them also provided significant corrosion inhibition of steel, as

  1. Local injection of the 90Y-labelled peptidic vector DOTATOC to control gliomas of WHO grades II and III: an extended pilot study.

    PubMed

    Schumacher, T; Hofer, S; Eichhorn, K; Wasner, M; Zimmerer, S; Freitag, P; Probst, A; Gratzl, O; Reubi, J-C; Maecke, R; Mueller-Brand, J; Merlo, A

    2002-04-01

    We have previously presented preliminary observations on targeting somatostatin receptor-positive malignant gliomas of all grades by local injection of the radiolabelled peptidic vector 90Y-DOTATOC. We now report on our more thorough clinical experience with this novel compound, focussing on low-grade and anaplastic gliomas. Small peptidic vectors have the potential to target invisible infiltrative disease within normal surrounding brain tissue, thereby opening a window of opportunity for early intervention. Five progressive gliomas of WHO grades II and III and five extensively debulked low-grade gliomas were treated with varying fractions of 90Y-DOTATOC. The vectors were locally injected into the resection cavity or into solid tumour. The activity per single injection ranged from 555 to 1,875 MBq, and the cumulative activity from 555 to 7,030 MBq, according to tumour volumes and eloquence of the affected brain area, yielding dose estimates from 76+/-15 to 312+/-62 Gy. Response was assessed by the clinical status, by steroid dependence and, every 4-6 months, by magnetic resonance imaging and fluorine-18 fluorodeoxyglucose positron emission tomography. In the five progressive gliomas, lasting responses were obtained for at least 13-45 months without the need for steroids. Radiopeptide brachytherapy had been the only modality applied to counter tumour progression. Interestingly, we observed the slow transformation of a solid, primarily inoperable anaplastic astrocytoma into a resectable multi-cystic lesion 2 years after radiopeptide brachytherapy. Based on these observations, we also assessed the feasibility of local radiotherapy following extensive debulking, which was well tolerated. Targeted beta-particle irradiation based on diffusible small peptidic vectors appears to be a promising modality for the treatment of malignant gliomas.

  2. Modulation of therapeutic antibody effector functions by glycosylation engineering: influence of Golgi enzyme localization domain and co-expression of heterologous beta1, 4-N-acetylglucosaminyltransferase III and Golgi alpha-mannosidase II.

    PubMed

    Ferrara, Claudia; Brünker, Peter; Suter, Tobias; Moser, Samuel; Püntener, Ursula; Umaña, Pablo

    2006-04-05

    The effector functions elicited by IgG antibodies strongly depend on the carbohydrate moiety linked to the Fc region of the protein. Therefore several approaches have been developed to rationally manipulate these glycans and improve the biological functions of the antibody. Overexpression of recombinant beta1,4-N-acetylglucosaminyltransferase III (GnT-III) in production cell lines leads to antibodies enriched in bisected oligosaccharides. Moreover, GnT-III overexpression leads to increases in non-fucosylated and hybrid oligosaccharides. Such antibody glycovariants have increased antibody-dependent cellular cytotoxicity (ADCC). To explore a further variable besides overexpression of GnT-III, we exchanged the localization domain of GnT-III with that of other Golgi-resident enzymes. Our results indicate that chimeric GnT-III can compete even more efficiently against the endogenous core alpha1,6-fucosyltransferase (alpha1,6-FucT) and Golgi alpha-mannosidase II (ManII) leading to higher proportions of bisected non-fucosylated hybrid glycans ("Glyco-1" antibody). The co-expression of GnT-III and ManII led to a similar degree of non-fucosylation as that obtained for Glyco-1, but the majority of the oligosaccharides linked to this antibody ("Glyco-2") are of the complex type. These glycovariants feature strongly increased ADCC activity compared to the unmodified antibody, while Glyco-1 (hybrid-rich) features reduced complement-dependent cytotoxicity (CDC) compared to Glyco-2 or unmodified antibody. We show that apart from GnT-III overexpression, engineering of GnT-III localization is a versatile tool to modulate the biological activities of antibodies relevant for their therapeutic application. (c) 2006 Wiley Periodicals, Inc.

  3. Corrosion chemistry closing comments: opportunities in corrosion science facilitated by operando experimental characterization combined with multi-scale computational modelling.

    PubMed

    Scully, John R

    2015-01-01

    Recent advances in characterization tools, computational capabilities, and theories have created opportunities for advancement in understanding of solid-fluid interfaces at the nanoscale in corroding metallic systems. The Faraday Discussion on Corrosion Chemistry in 2015 highlighted some of the current needs, gaps and opportunities in corrosion science. Themes were organized into several hierarchical categories that provide an organizational framework for corrosion. Opportunities to develop fundamental physical and chemical data which will enable further progress in thermodynamic and kinetic modelling of corrosion were discussed. These will enable new and better understanding of unit processes that govern corrosion at the nanoscale. Additional topics discussed included scales, films and oxides, fluid-surface and molecular-surface interactions, selected topics in corrosion science and engineering as well as corrosion control. Corrosion science and engineering topics included complex alloy dissolution, local corrosion, and modelling of specific corrosion processes that are made up of collections of temporally and spatially varying unit processes such as oxidation, ion transport, and competitive adsorption. Corrosion control and mitigation topics covered some new insights on coatings and inhibitors. Further advances in operando or in situ experimental characterization strategies at the nanoscale combined with computational modelling will enhance progress in the field, especially if coupling across length and time scales can be achieved incorporating the various phenomena encountered in corrosion. Readers are encouraged to not only to use this ad hoc organizational scheme to guide their immersion into the current opportunities in corrosion chemistry, but also to find value in the information presented in their own ways.

  4. Uroporphyrinogen-III synthase: Molecular cloning, nucleotide sequence, expression of a mouse full-length cDNA, and its localization on mouse chromosome 7

    SciTech Connect

    Xu, W.; Desnick, R.J.; Kozak, C.A.

    1995-04-10

    Uroporphyrinogen-III synthase, the fourth enzyme in the heme biosynthetic pathway, is responsible for the conversion of hydroxymethylbilane to the cyclic tetrapyrrole, uroporphyrinogen III. The deficient activity of URO-S is the enzymatic defect in congenital erythropoietic porphyria (CEP), an autosomal recessive disorder. For the generation of a mouse model of CEP, the human URO-S cDNA was used to screen 2 X 10{sup 6} recombinants from a mouse adult liver cDNA library. Ten positive clones were isolated, and dideoxy sequencing of the entire 1.6-kb insert of clone pmUROS-1 revealed 5{prime} and 3{prime} untranslated sequences of 144 and 623 bp, respectively, and an open reading frame of 798 bp encoding a 265-amino-acid polypeptide with a predicted molecular mass of 28,501 Da. The mouse and human coding sequences had 80.5 and 77.8% nucleotide and amino acid identity, respectively. The authenticity of the mouse cDNA was established by expression of the active monomeric enzyme in Escherichia coli. In addition, the analysis of two multilocus genetic crosses localized the mouse gene on chromosome 7, consistent with the mapping of the human gene to a position of conserved synteny on chromosome 10. The isolation, expression, and chromosomal mapping of this full-length cDNA should facilitate studies of the structure and organization of the mouse genomic sequence and the development of a mouse model of CEP for characterization of the disease pathogenesis and evaluation of gene therapy. 38 refs., 1 tab.

  5. Does the zone of injury in combat-related Type III open tibia fractures preclude the use of local soft tissue coverage?

    PubMed

    Burns, Travis C; Stinner, Daniel J; Possley, Daniel R; Mack, Andrew W; Eckel, Tobin T; Potter, Benjamin K; Wenke, Joseph C; Hsu, Joseph R

    2010-11-01

    Does the large zone of injury in high-energy, combat-related open tibia fractures limit the effectiveness of rotational flap coverage? Retrospective consecutive series. This study was conducted at Brooke Army Medical Center, Walter Reed Army Medical Center, and National Naval Medical Center between March 2003 and September 2007. We identified 67 extremities requiring a coverage procedure out of 213 consecutive combat-related Type III open diaphyseal tibia fractures. The 67 Type III B tibia fractures were treated with rotational or free flap coverage. Flap failure, reoperation, infection, amputation, time to union, and visual pain scale. There were no differences between the free and rotational flap cohorts with respect to demographic information, injury characteristics, or treatment before coverage. The reoperation and amputation rates were significantly lower for the rotational coverage group (30% and 9%) compared with the free flap group (64% and 36%; P = 0.05 and P = 0.03, respectively). The coverage failure rate was also lower for the rotational flap cohort (7% versus 27%, P = 0.08). The average time to fracture union for the free flap group was 9.5 months (range, 5-15.8 months) and 10.5 months (range, 3-41 months) for the rotational flap group (P = 0.99). There was a significantly lower amputation and reoperation rate for patients treated with rotational coverage. Contrary to our hypothesis and previous reports, the zone of injury in combat-related open tibia fractures does not preclude the use of local rotational coverage when practicable.

  6. Characterization of nuclear localization signals in the type III effectors HsvG and HsvB of the gall-forming bacterium Pantoea agglomerans.

    PubMed

    Weinthal, Dan M; Barash, Isaac; Tzfira, Tzvi; Gaba, Victor; Teper, Doron; Sessa, Guido; Manulis-Sasson, Shulamit

    2011-05-01

    HsvG and HsvB, two paralogous type III effectors of the gall-forming bacteria Pantoea agglomerans pv. gypsophilae and P. agglomerans pv. betae, determine host specificity on gypsophila and beet, respectively. They were previously shown to be DNA-binding proteins imported into host and non-host nuclei and might act as transcriptional activators. Sequence analysis of these effectors did not detect canonical nuclear localization signals (NLSs), but two basic amino acid clusters designated putative NLS1 and NLS2 were detected in their N-terminal and C-terminal regions, respectively. pNIA assay for nuclear import in yeast and bombardment of melon leaves with each of the NLSs fused to a 2xYFP reporter indicated that putative NLS1 and NLS2 were functional in transport of HsvG into the nucleus. A yeast two-hybrid assay showed that HsvB, HsvG, putative NLS1, putative NLS2, HsvG converted into HsvB, or HsvB converted into HsvG by exchanging the repeat domain, all interacted with AtKAP-α and importin-α3 of Arabidopsis thaliana. Deletion analysis of the NLS domains in HsvG suggested that putative NLS1 or NLS2 were required for pathogenicity on gypsophila cuttings and presumably for import of HsvG into the nucleus. This study demonstrates the presence of two functional NLSs in the type III effectors HsvG and HsvB.

  7. Corrosive effect of the type of soil in the systems of grounding more used (copper and stainless steel) for local soil samples from the city of Tunja (Colombia), by means of electrochemical techniques

    NASA Astrophysics Data System (ADS)

    Guerrero, L.; Salas, Y.; Blanco, J.

    2016-02-01

    In this work electrochemical techniques were used to determine the corrosion behaviour of copper and stainless steel electrodes, used in grounding varying soil type with which they react. A slight but significant change in the corrosion rate, linear polarization resistance and equivalent parameters in the technique of electrochemical impedance spectroscopy circuit was observed. Electrolytes in soils are slightly different depending on laboratory study, but the influence was noted in the retention capacity of water, mainly due to clays, affecting ion mobility and therefore measures such as the corrosion rate. Behaviour was noted in lower potential for copper corrosion, though the corrosion rate regardless of the type of soil, was much higher for electrodes based on copper, by several orders of magnitude.

  8. Phase I/II trial evaluating concurrent carbon-ion radiotherapy plus chemotherapy for salvage treatment of locally recurrent nasopharyngeal carcinoma.

    PubMed

    Kong, Lin; Gao, Jing; Hu, Jiyi; Hu, Weixu; Guan, Xiyin; Lu, Rong; Lu, Jiade J

    2016-12-22

    After definitive chemoradiotherapy for non-metastatic nasopharyngeal carcinoma (NPC), more than 10% of patients will experience a local recurrence. Salvage treatments present significant challenges for locally recurrent NPC. Surgery, stereotactic ablative body radiotherapy, and brachytherapy have been used to treat locally recurrent NPC. However, only patients with small-volume tumors can benefit from these treatments. Re-irradiation with X-ray-based intensity-modulated radiotherapy (IMXT) has been more widely used for salvage treatment of locally recurrent NPC with a large tumor burden, but over-irradiation to the surrounding normal tissues has been shown to cause frequent and severe toxicities. Furthermore, locally recurrent NPC represents a clinical entity that is more radio-resistant than its primary counterpart. Due to the inherent physical advantages of heavy-particle therapy, precise dose delivery to the target volume(s), without exposing the surrounding organs at risk to extra doses, is highly feasible with carbon-ion radiotherapy (CIRT). In addition, CIRT is a high linear energy transfer (LET) radiation and provides an increased relative biological effectiveness compared with photon and proton radiotherapy. Our prior work showed that CIRT alone to 57.5 GyE (gray equivalent), at 2.5 GyE per daily fraction, was well tolerated in patients who were previously treated for NPC with a definitive dose of IMXT. The short-term response rates at 3-6 months were also acceptable. However, no patients were treated with concurrent chemotherapy. Whether the addition of concurrent chemotherapy to CIRT can benefit locally recurrent NPC patients over CIRT alone has never been addressed. It is possible that the benefits of high-LET CIRT may make radiosensitizing chemotherapy unnecessary. We therefore implemented a phase I/II clinical trial to address these questions and present our methodology and results. The maximal tolerated dose (MTD) of re-treatment using raster

  9. Constituent Particle Clustering and Pitting Corrosion

    NASA Astrophysics Data System (ADS)

    Harlow, D. Gary

    2012-08-01

    Corrosion is a primary degradation mechanism that affects the durability and integrity of structures made of aluminum alloys, and it is a concern for commercial transport and military aircraft. In aluminum alloys, corrosion results from local galvanic coupling between constituent particles and the metal matrix. Due to variability in particle sizes, spatial location, and chemical composition, to name a few critical variables, corrosion is a complex stochastic process. Severe pitting is caused by particle clusters that are located near the material surface, which, in turn, serve as nucleation sites for subsequent corrosion fatigue crack growth. These evolution processes are highly dependent on the spatial statistics of particles. The localized corrosion growth rate is primarily dependent on the galvanic process perpetuated by particle-to-particle interactions and electrochemical potentials. Frequently, severe pits are millimeters in length, and these pits have a dominant impact on the structural prognosis. To accommodate large sizes, a model for three-dimensional (3-D) constituent particle microstructure is proposed. To describe the constituent particle microstructure in three dimensions, the model employs a fusion of classic stereological techniques, spatial point pattern analyses, and qualitative observations. The methodology can be carried out using standard optical microscopy and image analysis techniques.

  10. 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.

  11. 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...

  12. Potentiodynamic Corrosion Testing.

    PubMed

    Munir, Selin; Pelletier, Matthew H; Walsh, William R

    2016-09-04

    Different metallic materials have different polarization characteristics as dictated by the open circuit potential, breakdown potential, and passivation potential of the material. The detection of these electrochemical parameters identifies the corrosion factors of a material. A reliable and well-functioning corrosion system is required to achieve this. Corrosion of the samples was achieved via a potentiodynamic polarization technique employing a three-electrode configuration, consisting of reference, counter, and working electrodes. Prior to commencement a baseline potential is obtained. Following the stabilization of the corrosion potential (Ecorr), the applied potential is ramped at a slow rate in the positive direction relative to the reference electrode. The working electrode was a stainless steel screw. The reference electrode was a standard Ag/AgCl. The counter electrode used was a platinum mesh. Having a reliable and well-functioning in vitro corrosion system to test biomaterials provides an in-expensive technique that allows for the systematic characterization of the material by determining the breakdown potential, to further understand the material's response to corrosion. The goal of the protocol is to set up and run an in vitro potentiodynamic corrosion system to analyze pitting corrosion for small metallic medical devices.

  13. 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...

  14. Reduce FCC corrosion

    SciTech Connect

    Walker, H.B.

    1984-01-01

    Efficiency of fluid catalytic cracking (FCC) vapor recovery units can be significantly reduced by corrosion and fouling. The fundamentals of FCC light ends corrosion, including diagnoses, control and monitoring of hydrogen blistering, general metal loss, pitting, erosion and under-deposit attack are discussed, relating actual unit problems to effective treatment program solutions.

  15. 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.

  16. 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...

  17. 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...

  18. New Forum Addresses Microbiologically Influenced Corrosion

    DTIC Science & Technology

    2012-06-01

    Stainless Steels for Prestressed Concrete" Elisabeth Schwarzenbbck University of Bourgogne Third Place, Mars Fontana Category "Microelectrochemical...interpretation. Suflita described an idealized sampling scheme that included traditional culture techniques , molecular analysis, and meta- bolic...determine relationships between local- ized corrosion and microorganisms. Both techniques were used to optimize biodde additions. Larsen described

  19. Corrosion studies of iron and its alloys by means of57Fe Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Marco, J. F.; Dávalos, J.; Gracia, M.; Gancedo, J. R.

    1994-12-01

    Some of the advantages and limitations of Mössbauer spectroscopy when used in corrosion research are shown by using three examples taken from the work of the authors on (i) the passive layer of iron, (ii) the corrosion of weathering steels by SO2-polluted atmospheres and (iii) the performance of rust converters.

  20. Phase I/II Study of Erlotinib Combined With Cisplatin and Radiotherapy in Patients With Locally Advanced Squamous Cell Carcinoma of the Head and Neck

    SciTech Connect

    Herchenhorn, Daniel; Dias, Fernando L.; Viegas, Celia M.P.; Federico, Miriam H.; Araujo, Carlos Manoel M.; Small, Isabelle; Bezerra, Marcos; Fontao, Karina M.D.; Knust, Renata E.; Ferreira, Carlos G.; Martins, Renato G.

    2010-11-01

    Purpose: Erlotinib, an oral tyrosine kinase inhibitor, is active against head-and-neck squamous cell carcinoma (HNSCC) and possibly has a synergistic interaction with chemotherapy and radiotherapy. We investigated the safety and efficacy of erlotinib added to cisplatin and radiotherapy in locally advanced HNSCC. Methods and Materials: In this Phase I/II trial 100 mg/m{sup 2} of cisplatin was administered on Days 8, 29, and 50, and radiotherapy at 70 Gy was started on Day 8. During Phase I, the erlotinib dose was escalated (50 mg, 100 mg, and 150 mg) in consecutive cohorts of 3 patients, starting on Day 1 and continuing during radiotherapy. Dose-limiting toxicity was defined as any Grade 4 event requiring radiotherapy interruptions. Phase II was initiated 8 weeks after the last Phase I enrollment. Results: The study accrued 9 patients in Phase I and 28 in Phase II; all were evaluable for efficacy and safety. No dose-limiting toxicity occurred in Phase I, and the recommended Phase II dose was 150 mg. The most frequent nonhematologic toxicities were nausea/vomiting, dysphagia, stomatitis, xerostomia and in-field dermatitis, acneiform rash, and diarrhea. Of the 31 patients receiving a 150-mg daily dose of erlotinib, 23 (74%; 95% confidence interval, 56.8%-86.3%) had a complete response, 3 were disease free after salvage surgery, 4 had inoperable residual disease, and 1 died of sepsis during treatment. With a median 37 months' follow-up, the 3-year progression-free and overall survival rates were 61% and 72%, respectively. Conclusions: This combination appears safe, has encouraging activity, and deserves further studies in locally advanced HNSCC.

  1. Continuous 7-Days-A-Week External Beam Irradiation in Locally Advanced Cervical Cancer: Final Results of the Phase I/II Study

    SciTech Connect

    Serkies, Krystyna; Dziadziuszko, Rafal; Jassem, Jacek

    2012-03-01

    Purpose: To evaluate the feasibility and efficacy of definitive continuous 7-days-a-week pelvic irradiation without breaks between external beam radiotherapy and brachytherapy in locally advanced cervical cancer. Methods and Materials: Between November 1998 and December 1999, 30 patients with International Federation of Obstetrics and Gynecology Stage IIB or IIIB cervical cancer were included in a prospective Phase I/II study of continuous 7-days-a-week pelvic irradiation, to the total Manchester point B dose of 40.0-57.6 Gy. The first 13 patients (Group A) were given a daily tumor dose of 1.6 Gy, and the remaining 17 patients (Group B) were given 1.8 Gy. One or two immediate brachytherapy applications (point A dose 10-20 Gy, each) were performed in 28 cases. Results: Two patients did not complete the irradiation because of apparent early progression of disease during the irradiation. Eleven of the 28 evaluable patients (39%; 45% and 35% in Groups A and B, respectively) completed their treatment within the prescribed overall treatment time. Acute toxicity (including severe European Organisation for Research and Treatment of Cancer/Radiation Therapy Oncology Group Grade 3 and 4 effects in 40%) was experienced by 83% of patients and resulted in unplanned treatment interruptions in 40% of all patients (31% and 47% of patients in Groups A and B, respectively). Severe intestinal side effects occurred in 31% and 41% of Patients in Groups A and B, respectively (p = 0.71). The 5-year overall survival probability was 33%. Cancer recurrence occurred in 63% of patients: 20% inside and 57% outside the pelvis. Cumulative incidence of late severe bowel and urinary bladder toxicity at 24 months was 15%. Conclusion: Continuous irradiation in locally advanced cervical cancer is associated with a high incidence of severe acute toxicity, resulting in unplanned treatment interruptions. Late severe effects and survival after continuous radiotherapy do not substantially differ from

  2. Phase III Randomized Trial of Induction Chemotherapy in Patients With N2 or N3 Locally Advanced Head and Neck Cancer

    PubMed Central

    Cohen, Ezra E.W.; Karrison, Theodore G.; Kocherginsky, Masha; Mueller, Jeffrey; Egan, Robyn; Huang, Chao H.; Brockstein, Bruce E.; Agulnik, Mark B.; Mittal, Bharat B.; Yunus, Furhan; Samant, Sandeep; Raez, Luis E.; Mehra, Ranee; Kumar, Priya; Ondrey, Frank; Marchand, Patrice; Braegas, Bettina; Seiwert, Tanguy Y.; Villaflor, Victoria M.; Haraf, Daniel J.; Vokes, Everett E.

    2014-01-01

    Purpose Induction chemotherapy (IC) before radiotherapy lowers distant failure (DF) rates in locally advanced squamous cell carcinoma of the head and neck (SCCHN). The goal of this phase III trial was to determine whether IC before chemoradiotherapy (CRT) further improves survival compared with CRT alone in patients with N2 or N3 disease. Patients and Methods Treatment-naive patients with nonmetastatic N2 or N3 SCCHN were randomly assigned to CRT alone (CRT arm; docetaxel, fluorouracil, and hydroxyurea plus radiotherapy 0.15 Gy twice per day every other week) versus two 21-day cycles of IC (docetaxel 75 mg/m2 on day 1, cisplatin 75 mg/m2 on day 1, and fluorouracil 750 mg/m2 on days 1 to 5) followed by the same CRT regimen (IC + CRT arm). The primary end point was overall survival (OS). Secondary end points included DF-free survival, failure pattern, and recurrence-free survival (RFS). Results A total of 285 patients were randomly assigned. The most common grade 3 to 4 toxicities during IC were febrile neutropenia (11%) and mucositis (9%); during CRT (both arms combined), they were mucositis (49%), dermatitis (21%), and leukopenia (18%). Serious adverse events were more common in the IC arm (47% v 28%; P = .002). With a minimum follow-up of 30 months, there were no statistically significant differences in OS (hazard ratio, 0.91; 95% CI, 0.59 to 1.41), RFS, or DF-free survival. Conclusion IC did not translate into improved OS compared with CRT alone. However, the study was underpowered because it did not meet the planned accrual target, and OS was higher than predicted in both arms. IC cannot be recommended routinely in patients with N2 or N3 locally advanced SCCHN. PMID:25049329

  3. Localized deformation as a key precursor to initiation of intergranular stress corrosion cracking of austenitic stainless steels employed in nuclear power plants

    NASA Astrophysics Data System (ADS)

    Karlsen, Wade; Diego, Gonzalo; Devrient, Bastian

    2010-11-01

    Cold-work has been associated with the occurrence of intergranular cracking of stainless steels employed in light water reactors. This study examined the deformation behavior of AISI 304, AISI 347 and a higher stacking fault energy model alloy subjected to bulk cold-work and (for 347) surface deformation. Deformation microstructures of the materials were examined and correlated with their particular mechanical response under different conditions of temperature, strain rate and degree of prior cold-work. Select slow-strain rate tensile tests in autoclaves enabled the role of local strain heterogeneity in crack initiation in pressurized water reactor environments to be considered. The high stacking fault energy material exhibited uniform strain hardening, even at sub-zero temperatures, while the commercial stainless steels showed significant heterogeneity in their strain response. Surface treatments introduced local cold-work, which had a clear effect on the surface roughness and hardness, and on near-surface residual stress profiles. Autoclave tests led to transgranular surface cracking for a circumferentially ground surface, and intergranular crack initiation for a polished surface.

  4. 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,…

  5. 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,…

  6. 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.

  7. Corrosion Behavior of Ceramic Cup of Blast Furnace Hearth by Liquid Iron and Slag

    NASA Astrophysics Data System (ADS)

    Li, Yanglong; Cheng, Shusen; Wang, Zhifeng

    2016-10-01

    Three kinds of sample bricks of ceramic cups for blast furnace hearth were studied by dynamic corrosion tests based on different corrosion systems, i.e., liquid iron system, liquid slag system and liquid iron-slag system. Considering the influence of temperature and sample rotational speed, the corrosion profiles and mass loss of the samples were analyzed. In addition, the microstructure of the corroded samples was observed by optical microscope (OM) and scanning electron microscope (SEM). It was found that the corrosion profiles could be divided into iron corrosion region, slag corrosion region and iron-slag corrosion region via corrosion degree after iron-slag corrosion experiment. The most serious corrosion occurred in iron-slag corrosion region. This is due to Marangoni effect, which promotes a slag film formed between liquid iron and ceramic cup and results in local corrosion. The corrosion of the samples deepened with increasing temperature of liquid iron and slag from 1,623 K to 1,823 K. The variation of slag composition had greater influence on the erosion degree than that of rotational speed in this experiment. Taking these results into account the ceramic cup composition should be close to slag composition to decrease the chemical reaction. A microporous and strong material should be applied for ceramic cup.

  8. Boron Neutron Capture Therapy in the Treatment of Locally Recurred Head-and-Neck Cancer: Final Analysis of a Phase I/II Trial

    SciTech Connect

    Kankaanranta, Leena; Seppaelae, Tiina; Koivunoro, Hanna; Saarilahti, Kauko; Atula, Timo; Collan, Juhani; Salli, Eero; Kortesniemi, Mika; Uusi-Simola, Jouni; Vaelimaeki, Petteri; Maekitie, Antti; Seppaenen, Marko; Minn, Heikki; Revitzer, Hannu; Kouri, Mauri; Kotiluoto, Petri; Seren, Tom; Auterinen, Iiro; Savolainen, Sauli; Joensuu, Heikki

    2012-01-01

    Purpose: To investigate the efficacy and safety of boron neutron capture therapy (BNCT) in the treatment of inoperable head-and-neck cancers that recur locally after conventional photon radiation therapy. Methods and Materials: In this prospective, single-center Phase I/II study, 30 patients with inoperable, locally recurred head-and-neck cancer (29 carcinomas and 1 sarcoma) were treated with BNCT. Prior treatments consisted of surgery and conventionally fractionated photon irradiation to a cumulative dose of 50 to 98 Gy administered with or without concomitant chemotherapy. Tumor responses were assessed by use of the RECIST (Response Evaluation Criteria in Solid Tumors) and adverse effects by use of the National Cancer Institute common terminology criteria version 3.0. Intravenously administered L-boronophenylalanine-fructose (400 mg/kg) was administered as the boron carrier. Each patient was scheduled to be treated twice with BNCT. Results: Twenty-six patients received BNCT twice; four were treated once. Of the 29 evaluable patients, 22 (76%) responded to BNCT, 6 (21%) had tumor growth stabilization for 5.1 and 20.3 months, and 1 (3%) progressed. The median progression-free survival time was 7.5 months (95% confidence interval, 5.4-9.6 months). Two-year progression-free survival and overall survival were 20% and 30%, respectively, and 27% of the patients survived for 2 years without locoregional recurrence. The most common acute Grade 3 adverse effects were mucositis (54% of patients), oral pain (54%), and fatigue (32%). Three patients were diagnosed with osteoradionecrosis (each Grade 3) and one patient with soft-tissue necrosis (Grade 4). Late Grade 3 xerostomia was present in 3 of the 15 evaluable patients (20%). Conclusions: Most patients who have inoperable, locally advanced head-and-neck carcinoma that has recurred at a previously irradiated site respond to boronophenylalanine-mediated BNCT, but cancer recurrence after BNCT remains frequent. Toxicity was

  9. Solution chemistry of Mo(III) and Mo(IV): Thermodynamic foundation

    SciTech Connect

    Wang, Peiming; Wilson, L; Wesolowski, David J; Rosenqvist, Jorgen K; Anderko, Andrzej

    2010-01-01

    To investigate the behavior of molybdenum dissolution products in systems that approximate localized corrosion environments, solubility of Mo(III) in equilibrium with solid MoO2 has been determined at 80 C as a function of solution acidity, chloride concentration and partial pressure of hydrogen. The measurements indicate a strong increase in solubility with acidity and chloride concentration and a weak effect of hydrogen partial pressure. The obtained results have been combined with literature data for systems containing Mo(III), Mo(IV), and Mo(VI) in solutions to develop a comprehensive thermodynamic model of aqueous molybdenum chemistry. The model is based on a previously developed framework for simulating the properties of electrolyte systems ranging from infinite dilution to solid saturation or fused salt limit. To reproduce the measurements, the model assumes the presence of a chloride complex of Mo(III) (i.e., MoCl2+) and hydrolyzed species (MoOH2+, Mo(OH)2 +, and Mo(OH)3 0) in addition to the Mo3+ ion. The model generally reproduces the experimental data within experimental scattering and provides a tool for predicting the phase behavior and speciation in complex, concentrated aqueous solutions. Thus, it provides a foundation for simulating the behavior of molybdenum species in localized corrosion environments.

  10. 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.

  11. 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.

  12. Repeated iodine-125 seed implantations combined with external beam radiotherapy for the treatment of locally recurrent or metastatic stage III/IV non-small cell lung cancer: a retrospective study.

    PubMed

    Li, Wei; Dan, Gang; Jiang, Jianqing; Zheng, Yifeng; Zheng, Xiushan; Deng, Dan

    2016-09-13

    Recurrent or metastatic lung cancer is difficult to manage. This retrospective study aimed to assess the efficacy of repeated iodine-125 seed implantations combined with external beam radiotherapy (EBRT) for locally recurrent or metastatic stage-III/IV non-small cell lung cancer (NSCLC). Eighteen previously treated stage-III/IV NSCLC patients with local or metastatic recurrences underwent 1-to-3 iodine-125 implantations. Six of these patients received palliative EBRT and six patients received combined chemotherapy using gemcitabine and cisplatin. Near-term treatment efficacy was evaluated 3 months after seed implantation by comparing changes in tumor size on computed tomography images; the evaluated outcomes were complete response, partial response, stable disease, and local tumor control rate. Long-term efficacy was assessed based on 1- and 2-year survival rates. Patients were followed up for 6 to 50 months. The overall (i.e., complete + partial) response rate was 87.4 %. The local control rates after the first, second, and third years were 94.1, 58.8 and 41.2 %, respectively. The results of this study demonstrated that repeated implantation of radioactive particles combined with EBRT is a safe treatment that effectively controlled local recurrence and metastasis of stage III/IV NSCLC.

  13. Detection of stress corrosion cracking and general corrosion of mild steel in simulated defense nuclear waste solutions using electrochemical noise analysis

    NASA Astrophysics Data System (ADS)

    Edgemon, G. L.; Danielson, M. J.; Bell, G. E. C.

    1997-06-01

    Underground waste tanks fabricated from mild steel store more than 253 million liters of high level radioactive waste from 50 years of weapons production at the Hanford Site. The probable modes of corrosion failures are reported as nitrate stress corrosion cracking and pitting. In an effort to develop a waste tank corrosion monitoring system, laboratory tests were conducted to characterize electrochemical noise data for both uniform and localized corrosion of mild steel and other materials in simulated waste environments. The simulated waste solutions were primarily composed of ammonium nitrate or sodium nitrate and were held at approximately 97°C. The electrochemical noise of freely corroding specimens was monitored, recorded and analyzed for periods ranging between 10 and 500 h. At the end of each test period, the specimens were examined to correlate electrochemical noise data with corrosion damage. Data characteristic of uniform corrosion and stress corrosion cracking are presented.

  14. Novel systems for corrosion detection in piping

    SciTech Connect

    Raad, J.A. de; Fingerhut, M.P.

    1995-12-31

    Predictive maintenance requires accurate quantitative information. Nondestructive testing (NDT) tools have been able provide the necessary information, economically. Examination of the full surface of components is often required, which is contrary to the more typical spot location measurements. In addition, predictive maintenance inspection often requires the examination of hot and or insulated components. These challenges have been satisfied by recent developments in NDT and are applicable to a broad range of facility types such as tank terminals and pulp and paper plants. For non-insulated and above ground piping systems magnetic flux leakage (MFL) tools have recently been introduced into the marketplace. These tools allow very quick and reliable detection of local and extensive general corrosion, in carbon steel pipes or vessel walls, with nominal wall thicknesses of up to 15 mm. A relatively new method for detection of corrosion under insulated components is the RTD-Incotest, pulse eddy current (PEC) system. This system can also provide the components remaining wall thickness at general corrosion locations. Demand for corrosion detection under insulation on piping has also been satisfied by new dynamic Real-Time-Radiography systems. These systems are relatively fast, but the concept itself and its weight require close human access to the pipe, hence, some method of accessing above ground piping is required. Nevertheless, the systems satisfy a market demand. Time-of-flight-Diffraction (TOFD) for detection and sizing of weld root corrosion as well as coherent color enhanced thickness mapping will also be introduced.

  15. Fungal induced corrosion of wire rope exposed in humid atmospheric conditions

    SciTech Connect

    Little, B.; Ray, R.; Hart, K.; Wagner, P.

    1995-03-01

    Localized corrosion of carbon steel wire rope stored in a humid environment on wooden spools was caused by organic acid and carbon dioxide production by fungi growing directly on the wood. Fungal growth was observed on the interiors of wooden spools and corrosion was most severe on the wrap of wire in direct contact with the wood. Laboratory experiments were designed to demonstrate a causal relationship between storage conditions, fungal growth, and localized corrosion.

  16. Influence of Direct Current Electric Field on Corrosion Behavior of Tin Under a Thin Electrolyte Layer

    NASA Astrophysics Data System (ADS)

    Huang, H. L.; Bu, F. R.; Tian, J.; Liu, D.

    2017-08-01

    The influence of a direct current electric field (DCEF) on corrosion behavior of tin under a thin electrolyte layer was investigated based on an array electrode technology by polarization, electrochemical impedance spectroscopy and surface analysis. The experimental results indicate that the corrosion rate of tin near the positive plate of DCEF increases with increased electric field intensity, which could be attributed to the acceleration of the migration of ions, the removal of corrosion products under DCEF and the damage of tin surface oxide film. Furthermore, tin at different positions in a DCEF exhibits different corrosion behavior, which could be ascribed to the difference of the local corrosion environment caused by the DCEF.

  17. 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)

  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. 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.

  20. Recommend design of filler metal to minimize carbon steel weld metal preferential corrosion in CO2-saturated oilfield produced water

    NASA Astrophysics Data System (ADS)

    Lu, Yongxin; Jing, Hongyang; Han, Yongdian; Feng, Zhicao; Xu, Lianyong

    2016-12-01

    The paper proposes a recommend design for the alloying elements in the filler metal to minimize preferential weld corrosion of carbon steel. The tensile and corrosion resistance properties of the weld metal are considerably improved by using a filler metal containing alloying elements according to the recommended design. Analysis of the morphology and composition of corrosion products on weld metals showed that the common weld metal suffered severe localized corrosion, whereas the weld metal with the alloying elements exhibited uniform corrosion. Based on these results, a tentative mechanism of CO2 corrosion resistance for both weld metals has been proposed.

  1. Three-Dimensional Localization of the α and β Subunits and of the II-III Loop in the Skeletal Muscle L-type Ca2+ Channel*

    PubMed Central

    Szpyt, John; Lorenzon, Nancy; Perez, Claudio F.; Norris, Ethan; Allen, Paul D.; Beam, Kurt G.; Samsó, Montserrat

    2012-01-01

    The L-type Ca2+ channel (dihydropyridine receptor (DHPR) in skeletal muscle acts as the voltage sensor for excitation-contraction coupling. To better resolve the spatial organization of the DHPR subunits (α1s or CaV1.1, α2, β1a, δ1, and γ), we created transgenic mice expressing a recombinant β1a subunit with YFP and a biotin acceptor domain attached to its N- and C- termini, respectively. DHPR complexes were purified from skeletal muscle, negatively stained, imaged by electron microscopy, and subjected to single-particle image analysis. The resulting 19.1-Å resolution, three-dimensional reconstruction shows a main body of 17 × 11 × 8 nm with five corners along its perimeter. Two protrusions emerge from either face of the main body: the larger one attributed to the α2-δ1 subunit that forms a flexible hook-shaped feature and a smaller protrusion on the opposite side that corresponds to the II-III loop of CaV1.1 as revealed by antibody labeling. Novel features discernible in the electron density accommodate the atomic coordinates of a voltage-gated sodium channel and of the β subunit in a single docking possibility that defines the α1-β interaction. The β subunit appears more closely associated to the membrane than expected, which may better account for both its role in localizing the α1s subunit to the membrane and its suggested role in excitation-contraction coupling. PMID:23118233

  2. RESILIENCE: Phase III Randomized, Double-Blind Trial Comparing Sorafenib With Capecitabine Versus Placebo With Capecitabine in Locally Advanced or Metastatic HER2-Negative Breast Cancer.

    PubMed

    Baselga, José; Zamagni, Claudio; Gómez, Patricia; Bermejo, Begoña; Nagai, Shigenori E; Melichar, Bohuslav; Chan, Arlene; Mángel, Lászlo; Bergh, Jonas; Costa, Frederico; Gómez, Henry L; Gradishar, William J; Hudis, Clifford A; Rapoport, Bernardo L; Roché, Henri; Maeda, Patricia; Huang, Liping; Meinhardt, Gerold; Zhang, Joshua; Schwartzberg, Lee S

    2017-05-22

    Sorafenib is a multikinase inhibitor with antiangiogenic/antiproliferative activity. In this randomized, double-blind, placebo-controlled phase III trial, we assessed first- or second-line capecitabine with sorafenib or placebo in patients with locally advanced/metastatic HER2-negative breast cancer resistant to a taxane and anthracycline and with known estrogen/progesterone receptor status. A total of 537 patients were randomized to capecitabine 1000 mg/m(2) orally twice per day for days 1 to 14 every 21 days with oral sorafenib 600 mg/d or placebo. The primary end point was progression-free survival (PFS). Patients were stratified according to hormone receptor status, previous chemotherapies for metastatic breast cancer, and geographic region. Treatment with sorafenib with capecitabine, compared with capecitabine with placebo, did not prolong median PFS (5.5 vs. 5.4 months; hazard ratio [HR], 0.973; 95% confidence interval [CI], 0.779-1.217; P = .811) or overall survival (OS; 18.9 vs. 20.3 months; HR, 1.195; 95% CI, 0.943-1.513; P = .140); or enhance overall response rate (ORR; 13.5% vs. 15.5%; P = .515). Any grade toxicities (sorafenib vs. placebo) included palmar-plantar erythrodysesthesia syndrome (PPES; 79.2% vs. 59.6%), diarrhea (47.3% vs. 37.8%), mucosal inflammation (15.4% vs. 6.7%), and hypertension (26.2% vs. 5.6%). Grade 3/4 toxicities included PPES (15.4% vs. 7.1%), diarrhea (4.2% vs. 6.4%), and vomiting (3.5% vs. 0.7%). The combination of sorafenib with capecitabine did not improve PFS, OS, or ORR in patients with HER2-negative advanced breast cancer. Rates of Grade 3 toxicities were higher in the sorafenib arm. Copyright © 2017. Published by Elsevier Inc.

  3. Characterization of Xenopus egg membrane microdomains containing uroplakin Ib/III complex: roles of their molecular interactions for subcellular localization and signal transduction.

    PubMed

    Mahbub Hasan, A K M; Ou, Zhize; Sakakibara, Keiichi; Hirahara, Shino; Iwasaki, Tetsushi; Sato, Ken-ichi; Fukami, Yasuo

    2007-02-01

    A single-transmembrane protein uroplakin III (UPIII) and its tetraspanin binding-partner uroplakin Ib (UPIb) are members of the UP proteins that were originally identified in mammalian urothelium. In Xenopus laevis eggs, these proteins: xUPIII and xUPIb, are components of the cholesterol-enriched membrane microdomains or "rafts" and involved in the sperm-egg membrane interaction and subsequent egg activation signaling via Src tyrosine kinase at fertilization. Here, we investigate whether the xUPIII-xUPIb complex is in close proximity to CD9, a tetraspanin that has been implicated in the sperm-egg fusion in the mouse and GM1, a ganglioside typically enriched in egg rafts. Preparation of the egg membrane microdomains using different non-ionic detergents (Brij 98 and Triton X-100), chemical cross-linking, co-immunoprecipitation, in vitro kinase assay and in vitro fertilization experiments demonstrated that GM1, but not CD9, is in association with the xUPIII-xUPIb complex and contributes to the sperm-dependent egg activation. Transfection experiments using HEK293 cells demonstrated that xUPIII and xUPIb localized efficiently to the cholesterol-dependent membrane microdomains when they were co-expressed, whereas co-expression of xUPIII and CD9, instead of xUPIb, did not show this effect. Furthermore, xUPIII and xUPIb were shown to suppress kinase activity of the wild type, but not a constitutively active form of, Xenopus Src protein co-expressed in HEK293 cells. These results provide novel insight into the molecular architecture of the egg membrane microdomains containing xUPIII, xUPIb and Src, which may contribute to the understanding of sperm-egg interaction and signaling during Xenopus fertilization.

  4. Three-dimensional localization of the α and β subunits and of the II-III loop in the skeletal muscle L-type Ca2+ channel.

    PubMed

    Szpyt, John; Lorenzon, Nancy; Perez, Claudio F; Norris, Ethan; Allen, Paul D; Beam, Kurt G; Samsó, Montserrat

    2012-12-21

    The L-type Ca(2+) channel (dihydropyridine receptor (DHPR) in skeletal muscle acts as the voltage sensor for excitation-contraction coupling. To better resolve the spatial organization of the DHPR subunits (α(1s) or Ca(V)1.1, α(2), β(1a), δ1, and γ), we created transgenic mice expressing a recombinant β(1a) subunit with YFP and a biotin acceptor domain attached to its N- and C- termini, respectively. DHPR complexes were purified from skeletal muscle, negatively stained, imaged by electron microscopy, and subjected to single-particle image analysis. The resulting 19.1-Å resolution, three-dimensional reconstruction shows a main body of 17 × 11 × 8 nm with five corners along its perimeter. Two protrusions emerge from either face of the main body: the larger one attributed to the α(2)-δ1 subunit that forms a flexible hook-shaped feature and a smaller protrusion on the opposite side that corresponds to the II-III loop of Ca(V)1.1 as revealed by antibody labeling. Novel features discernible in the electron density accommodate the atomic coordinates of a voltage-gated sodium channel and of the β subunit in a single docking possibility that defines the α1-β interaction. The β subunit appears more closely associated to the membrane than expected, which may better account for both its role in localizing the α(1s) subunit to the membrane and its suggested role in excitation-contraction coupling.

  5. 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.

  6. Corrosion Experience Data Requirements.

    DTIC Science & Technology

    1988-01-01

    Pattern .... ........... .50 5-6 Focused Transducer Concept Showing the Diverging Beam from the Point of Focus as it Enters Parallel into the Steel Plate...and inspection standards. Although the ABS rules for building and classing steel vessels do not mention explicitly the allowances adopted, they have...the effects of a corrosive environment on crack growth of ship steel in terms of the probability of failure. The results indicate that corrosion is a

  7. Optimization of a Three-Component Green Corrosion Inhibitor Mixture for Using in Cooling Water by Experimental Design

    NASA Astrophysics Data System (ADS)

    Asghari, E.; Ashassi-Sorkhabi, H.; Ahangari, M.; Bagheri, R.

    2016-04-01

    Factors such as inhibitor concentration, solution hydrodynamics, and temperature influence the performance of corrosion inhibitor mixtures. The simultaneous studying of the impact of different factors is a time- and cost-consuming process. The use of experimental design methods can be useful in minimizing the number of experiments and finding local optimized conditions for factors under the investigation. In the present work, the inhibition performance of a three-component inhibitor mixture against corrosion of St37 steel rotating disk electrode, RDE, was studied. The mixture was composed of citric acid, lanthanum(III) nitrate, and tetrabutylammonium perchlorate. In order to decrease the number of experiments, the L16 Taguchi orthogonal array was used. The "control factors" were the concentration of each component and the rotation rate of RDE and the "response factor" was the inhibition efficiency. The scanning electron microscopy and energy dispersive x-ray spectroscopy techniques verified the formation of islands of adsorbed citrate complexes with lanthanum ions and insoluble lanthanum(III) hydroxide. From the Taguchi analysis results the mixture of 0.50 mM lanthanum(III) nitrate, 0.50 mM citric acid, and 2.0 mM tetrabutylammonium perchlorate under the electrode rotation rate of 1000 rpm was found as optimum conditions.

  8. Corrosion fundamentals and corrosion effects on aboveground storage tanks

    SciTech Connect

    Fitzgerald, J.H. III

    1995-12-31

    Corrosion is an electrochemical process that involves ion migration and electron flow. The electrochemical process is explained and the four elements of the basic cell are described--anode, cathode, electrolyte and return circuit. The corrosion mechanisms affecting underground structures can be divided into two main categories--naturally occurring corrosion and stray current corrosion. Several examples of each are shown. These mechanisms of corrosion are applicable to aboveground storage tanks. Various types of exterior and interior corrosion of ASTs are explained in the light of electrochemical theory.

  9. RpoS and quorum sensing control expression and polar localization of Vibrio cholerae chemotaxis cluster III proteins in vitro and in vivo.

    PubMed

    Ringgaard, Simon; Hubbard, Troy; Mandlik, Anjali; Davis, Brigid M; Waldor, Matthew K

    2015-08-01

    The diarrheal pathogen Vibrio cholerae contains three gene clusters that encode chemotaxis-related proteins, but only cluster II appears to be required for chemotaxis. Here, we present the first characterization of V. cholerae's 'cluster III' chemotaxis system. We found that cluster III proteins assemble into foci at bacterial poles, like those formed by cluster II proteins, but the two systems assemble independently and do not colocalize. Cluster III proteins are expressed in vitro during stationary phase and in conjunction with growth arrest linked to carbon starvation. This expression, as well as expression in vivo in suckling rabbits, is dependent upon RpoS. V. cholerae's CAI-1 quorum sensing (QS) system is also required for cluster III expression in stationary phase and modulates its expression in vivo, but is not required for cluster III expression in response to carbon starvation. Surprisingly, even though the CAI-1 and AI-2 QS systems are thought to feed into the same signaling pathway, the AI-2 system inhibited cluster III gene expression, revealing that the outputs of the two QS systems are not always the same. The distinctions between genetic determinants of cluster III expression in vitro and in vivo highlight the distinctive nature of the in vivo environment.

  10. 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 ...

  11. 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 ...

  12. 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...

  13. 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...

  14. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique

    PubMed Central

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-01-01

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)2 solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete. PMID:27618054

  15. Experimental Study on Rebar Corrosion Using the Galvanic Sensor Combined with the Electronic Resistance Technique.

    PubMed

    Xu, Yunze; Li, Kaiqiang; Liu, Liang; Yang, Lujia; Wang, Xiaona; Huang, Yi

    2016-09-08

    In this paper, a new kind of carbon steel (CS) and stainless steel (SS) galvanic sensor system was developed for the study of rebar corrosion in different pore solution conditions. Through the special design of the CS and SS electronic coupons, the electronic resistance (ER) method and zero resistance ammeter (ZRA) technique were used simultaneously for the measurement of both the galvanic current and the corrosion depth. The corrosion processes in different solution conditions were also studied by linear polarization resistance (LPR) and the measurements of polarization curves. The test result shows that the galvanic current noise can provide detailed information of the corrosion processes. When localized corrosion occurs, the corrosion rate measured by the ER method is lower than the real corrosion rate. However, the value measured by the LPR method is higher than the real corrosion rate. The galvanic current and the corrosion current measured by the LPR method shows linear correlation in chloride-containing saturated Ca(OH)₂ solution. The relationship between the corrosion current differences measured by the CS electronic coupons and the galvanic current between the CS and SS electronic coupons can also be used to evaluate the localized corrosion in reinforced concrete.

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

    PubMed

    Finkenstadt, Victoria L; Côté, Gregory L; Willett, J L

    2011-06-01

    Corrosion of metals is a serious and challenging problem faced worldwide by industry. Purified Leuconostoc mesenteroides exopolysaccharide (EPS) coatings, cast from aqueous solution, inhibited the corrosion of low-carbon steel as determined by electrochemical impedance spectroscopy (EIS). There were two different corrosion behaviors exhibited when EPS films from different strains were cast onto the steel. One EPS coating reacted immediately with the steel substrate to form an iron (III) oxide layer ("rust") during the drying process while another did not. The samples that did not flash corrode had higher corrosion inhibition and formed an iron (II) passivation layer during EIS testing that persisted after the cells were disassembled. Corrosion inhibition was strain-specific as polysaccharides with similar structure did not have the same corrosion potential.

  17. Effects of Dissimilar Metal Coupling, Potential Distribution, and Temper Condition on Galvanic Corrosion of 5086 Aluminum Alloy in Synthetic Seawater

    DTIC Science & Technology

    1978-01-01

    of corrosion product deposits on both anodic and cathodic surfaces. Coverage of the surface of the aluminm (anodic) member of couples with corrosion... products tends to promote the operation of local corrosion modes. Correlations have been imde between corrosion product distribution and the...brass > 1040 steel. The effect of dissimilar metal coupling decreases with time due to the formation cf corro0ion product deposits on both annuic and

  18. Characterization of corrosion scale formed on stainless steel delivery pipe for reclaimed water treatment.

    PubMed

    Cui, Yong; Liu, Shuming; Smith, Kate; Yu, Kanghua; Hu, Hongying; Jiang, Wei; Li, Yuhong

    2016-01-01

    To reveal corrosion behavior of stainless steel delivery pipe used in reclaimed water treatment, this research focused on the morphological, mineralogical and chemical characteristics of stainless steel corrosion scale and corroded passive film. Corrosion scale and coupon samples were taken from a type 304 pipe delivering reclaimed water to a clear well in service for more than 12 years. Stainless steel corrosion scales and four representative pipe coupons were investigated using mineralogy and material science research methods. The results showed corrosion scale was predominantly composed of goethite, lepidocrocite, hematite, magnetite, ferrous oxide, siderite, chrome green and chromite, the same as that of corroded pipe coupons. Hence, corrosion scale can be identified as podiform chromite deposit. The loss of chromium in passive film is a critical phenomenon when stainless steel passive film is damaged by localized corrosion. This may provide key insights toward improving a better comprehension of the formation of stainless steel corrosion scale and the process of localized corrosion. The localized corrosion behavior of stainless steel is directly connected with reclaimed water quality parameters such as residual chlorine, DO, Cl(-) and SO4(2-). In particular, when a certain amount of residual chlorine in reclaimed water is present as an oxidant, ferric iron is the main chemical state of iron minerals.

  19. Effect of Heat Treatment on Corrosion and Stress Corrosion Cracking of S32205 Duplex Stainless Steel in Caustic Solution

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Ananya; Singh, Preet M.

    2009-06-01

    Duplex stainless steels (DSSs) have generally performed very well in caustic environments. However, some corrosion and stress corrosion cracking (SCC) of DSSs have been reported in different pulp mill environments employing caustic solutions. Studies have shown that the corrosion and SCC susceptibility of DSSs depend on the alloy composition and microstructure of the steel. In this study, the effect of a sulfide-containing caustic environment (pulping liquor) and material properties (DSS alloy composition and microstructure) on the corrosion and SCC of DSSs was evaluated. During metal fabrication processes, localized areas of DSSs may be exposed to different temperatures and cooling rates, which may lead to changes in the microstructure in these regions. This change in microstructure, in turn, may affect the general and localized corrosion or SCC susceptibility of the affected area as compared to the rest of the metal. Hence, the effect of different annealing and aging temperatures as well as cooling rates on the microstructure and corrosion behavior of S32205 DSSs in caustic environment was evaluated. The results showed that changes in the microstructure of S32205 DSSs due to selected heat treatments did not have a significant effect on the general corrosion susceptibility of the steel in caustic environment, but its SCC susceptibility varied with changes in microstructures.

  20. 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.

  1. 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.

  2. Induction TPF followed by concomitant treatment versus concomitant treatment alone in locally advanced head and neck cancer. A phase II-III trial.

    PubMed

    Ghi, M G; Paccagnella, A; Ferrari, D; Foa, P; Alterio, D; Codecà, C; Nolè, F; Verri, E; Orecchia, R; Morelli, F; Parisi, S; Mastromauro, C; Mione, C A; Rossetto, C; Polsinelli, M; Koussis, H; Loreggian, L; Bonetti, A; Campostrini, F; Azzarello, G; D'Ambrosio, C; Bertoni, F; Casanova, C; Emiliani, E; Guaraldi, M; Bunkheila, F; Bidoli, P; Niespolo, R M; Gava, A; Massa, E; Frattegiani, A; Valduga, F; Pieri, G; Cipani, T; Da Corte, D; Chiappa, F; Rulli, E

    2017-09-01

    Platinum-based chemoradiation (CCRT) is the standard treatment for Locally Advanced Head and Neck Squamous-Cell Carcinoma (LAHNSCC). Cetuximab/RT (CET/RT) is an alternative treatment option to CCRT. The efficacy of induction chemotherapy (IC) followed by chemoradiation compared to chemoradiation alone has not been demonstrated in randomized clinical trials. The goals of this phase II-III trial were to assess: (i) the overall survival (OS) of IC versus no-induction (no-IC) and (ii) the Grade 3-4 in-field mucosal toxicity of CCRT versus CET/RT. The present paper focuses on the analysis of efficacy. Patients with LAHNSCC were randomized to receive concomitant treatment alone [CCRT (Arm A1) or CET/RT (Arm A2)], or three cycles of induction docetaxel/cisplatin/5 fluorouracil (TPF) followed by CCRT (Arm B1) or followed by CET/RT (Arm B2). The superiority hypothesis of OS comparison of IC versus no-IC (Arms B1 + B2 versus A1 + A2) required 204 deaths to detect an absolute 3-year OS difference of 12% (HR 0.675, with 80% power at two-sided 5% significance level). 414 out of 421 patients were finally analyzed: 206 in the IC and 208 in the no-IC arm. Six patients were excluded because of major violation and one because of metastatic disease at diagnosis. With a median follow-up of 44.8 months, OS was significantly higher in the IC arm (HR 0.74; 95% CI 0.56-0.97; P = 0.031). Complete Responses (P = 0.0028), Progression Free Survival (P = 0.013) and the Loco-regional Control (P = 0.036) were also significantly higher in the IC arm. Compliance to concomitant treatments was not affected by induction TPF. IC followed by concomitant treatment improved the outcome of patients with LAHNSCC without compromising compliance to the concomitant treatments. The degree of the benefit of IC could be different according to the type of the subsequent concomitant strategy. NCT01086826, www.clinicaltrials.gov.

  3. Triptorelin 6-month formulation in the management of patients with locally advanced and metastatic prostate cancer: an open-label, non-comparative, multicentre, phase III study.

    PubMed

    Lundström, Eija A; Rencken, Rupert K; van Wyk, Johann H; Coetzee, Lance J E; Bahlmann, Johann C M; Reif, Simon; Strasheim, Erdam A; Bigalke, Martin C; Pontin, Alan R; Goedhals, Louis; Steyn, Douw G; Heyns, Chris F; Aldera, Luigi A; Mackenzie, Thomas M; Purcea, Daniela; Grosgurin, Pierre Y; Porchet, Hervé C

    2009-01-01

    Triptorelin 6-month formulation was developed to offer greater convenience to both patients and physicians by reducing the injection frequency. The efficacy, pharmacokinetics and safety of a new 6-month formulation of triptorelin were investigated over 12 months (48 weeks). The primary objective was to evaluate the formulation in achieving castrate serum testosterone levels (< or = 1.735 nmol/L or < or = 50 ng/dL) on day 29 and in maintaining castration at months 2-12. Absence of luteinizing hormone (LH) stimulation and change in prostate-specific antigen (PSA) level were also assessed. An open-label, non-comparative, phase III study in 120 patients with advanced prostate cancer was conducted from July 2006 to August 2007 in private and public institutions in South Africa. Each patient received two consecutive intramuscular injections of triptorelin embonate (pamoate) 22.5 mg at an interval of 24 weeks. In all patients, testosterone (primary outcome measurement) was measured at baseline and then every 4 weeks; LH was measured before and 2 hours after the two injections. PSA was measured on day 1 and at weeks 12, 24, 36 and 48. Adverse events were recorded at each visit. In the intent-to-treat population, 97.5% (95% CI 92.9, 99.5) of patients achieved castrate serum testosterone levels by day 29, and 93.0% (95% CI 86.8, 97.0) maintained castration at months 2-12. After the second injection, 98.3% of patients showed absence of LH stimulation. The most frequent drug-related adverse events were hot flushes (71.7% of patients). No patient withdrew from the study as a result of an adverse event. The triptorelin 6-month formulation was well tolerated and was able to achieve and maintain castration for the treatment of locally advanced and metastatic prostate cancer. By reducing the frequency of required injections, this new formulation offers a more convenient treatment regimen. (Clinical Trial Registration,NCT00751790 at www.clinicaltrials.gov).

  4. Adsorption and corrosion-inhibiting effect of Dacryodis edulis extract on low-carbon-steel corrosion in acidic media.

    PubMed

    Oguzie, E E; Enenebeaku, C K; Akalezi, C O; Okoro, S C; Ayuk, A A; Ejike, E N

    2010-09-01

    The inhibition of low-carbon-steel corrosion in 1M HCl and 0.5M H(2)SO(4) by extracts of Dacryodis edulis (DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic matter onto the steel surface in a concentration-dependent manner and involved both protonated and molecular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract.

  5. EFFECTS OF CHEMISTRY AND OTHER VARIABLES ON CORROSION AND STRESS CORROSION CRACKING IN HANFORD DOUBLE SHELL TANKS

    SciTech Connect

    BROWN MH

    2008-11-13

    Laboratory testing was performed to develop a comprehensive understanding of the corrosivity of the tank wastes stored in Double-Shell Tanks using simulants primarily from Tanks 241-AP-105, 241-SY-103 and 241-AW-105. Additional tests were conducted using simulants of the waste stored in 241-AZ-102, 241-SY-101, 241-AN-107, and 241-AY-101. This test program placed particular emphasis on defining the range of tank waste chemistries that do not induce the onset of localized forms of corrosion, particularly pitting and stress corrosion cracking. This document summarizes the key findings of the research program.

  6. Microbiologically Influenced Corrosion: Global Phenomena, Local Mechanisms

    DTIC Science & Technology

    2011-02-17

    thermodynamic. kinetic, and alteration of the nature ol" the reduction reaction itself. Thermodynamic arguments for ennoblement suggest that either a pH decrease...account for an ennoblement of about 300 mV, assuming that the exchange current density for the oxygen reduction reaction (i 0;)and the calhodic...enzymes to accelerate electrochemical reactions and noted the inhibitory effect of sodium azide on enzyme electrocatalysis of oxygen reduction. They

  7. PERFORMACE OF MULTI-PROBE CORROSION MONITORING SYSTEMS AT THE HANFORD SITE

    SciTech Connect

    CAROTHERS KD; BOOMER KD; ANDA VS; DAHL MM; EDGEMON GL

    2010-01-14

    Between 2007 and 2009, several different multi-probe corrosion monitoring systems were designed and installed in high-level nuclear waste tanks at the U.S. Department of Energy's Hanford Site in WaShington State. The probe systems are being monitored to ensure waste tanks operate in regions that minimize localized corrosion (i.e., pitting) and stress corrosion cracking. The corrosion monitoring systems have been installed in wastes with different chemistry types. An ongoing effort during the same time period has generated non-radioactive simulants that are tested in the laboratory to establish baseline corrosion monitoring system performance and characterize data to allow interpretation of readings from the multiple corrosion monitoring systems. Data collection from these monitoring systems has reached the point where the results allow comparison with the laboratory testing. This paper presents analytical results from the corrosion monitoring system development program.

  8. 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.

  9. 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.

  10. Improvement of the Corrosion Resistance of Turbine Engine Bearings

    DTIC Science & Technology

    1984-02-01

    also explored. A galvanic cell could greatly increase the rate ol corrosion. It consists of two dissimilar metals immersed in a conductive solution. To...are more significant contributors to the water content of the oil than the water washing procedure (Table 3). 4. Galvanic Cell Tests Galvanic...and water contamination of preservatives and oils, all of the elements required for galvanic corrosion are present. In a bearing, a local galvanic

  11. 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.

  12. 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.

  13. Detection of crevice corrosion of metallic alloys by optical interferometry

    SciTech Connect

    Habib, K.

    1999-11-01

    In the present investigation, an optical corrosion-meter has been developed for materials testing and evaluation of different corrosion phenomena. The idea of the optical corrosion-meter was established based on principles of 3D-holographic interferometry for measuring microsurface dissolution, i.e. mass loss, and on those of electrochemistry for measuring the bulk electronic current, i.e. corrosion current of metallic samples in aqueous solutions. In the present work, an early stage of crevice corrosion of a titanium alloy, a carbon steel and a pure aluminum in seawater was monitored in situ by the optical corrosion-meter during the cyclic polarization test. The observations of crevice corrosion were basically interferometric perturbations detected only on the surface of the titanium alloy and the carbon steel underneath a crevice assembly, made of Teflon bolt, Teflon nut, and Teflon washer. The crevice assembly used on all tested samples to create a differential aeration cell between the surface of the sample and areas underneath the crevice assembly in seawater. Each Teflon washer contained radial grooves and had 20 plateaus which formed crevices ( shield areas) when pressed against the surface of the sample. The interferometric perturbations interpreted as a localized corrosion in a form of an early crevice corrosion of a depth ranged between 0.3 pm to several micrometers. Consequently, results of the present work indicate that holographic interferometry is very useful technique as a 3D-interferometric microscope for monitoring crevice corrosion at the initiation stage of the phenomenon for different metallic samples in aqueous solutions.

  14. 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.

  15. Immunohistochemical localization of procollagens. I. Light microscopic distribution of procollagen I, III and IV antigenicity in the rat incisor tooth by the indirect peroxidase-anti-peroxidase method.

    PubMed

    Cournil, I; Leblond, C P; Pomponio, J; Hand, A R; Sederlof, L; Martin, G R

    1979-07-01

    Frozen sections of the growing end of the rat incisor tooth were exposed to antisera or affinity prepared antibodies against partially purified type I, II, or IV procollagen in the hope of detecting the location of the corresponding antigens by the peroxidase-anti-peroxidase technique. The distribution of immunostaining was similar with antisera as with purified antibodies of a given type, but differed for each type; that is, predentin, odontoblasts, pulp and periodontal tissue were the sites of type I; blood vessel walls, pulp and periodontal tissue, of type III; and basement membranes, of type IV antigenicity. It was demonstrated, at least in cases of type I and III, that immunostaining detected the corresponding procollagens and related substances, but not the corresponding collagens. The interpretation of these observations is that: 1) odontoblasts elaborate procollagen I for release to predentin and subsequent transformation to dentinal collagen I; 2) pulp and periodontal cells produce procollagens I and III which presumably become collagens I and III respectively, while the adventitial cells of blood vessels give rise to collagen III; and 3) procollagen IV is associated with basement membranes and, occasionally, adjacent cells.

  16. Solving A Corrosion Problem

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The corrosion problem, it turned out, stemmed from the process called electrolysis. When two different metals are in contact, an electrical potential is set up between them; when the metals are surrounded by an electrolyte, or a conducting medium, the resulting reaction causes corrosion, often very rapid corrosion. In this case the different metals were the copper grounding system and the ferry's aluminum hull; the dockside salt water in which the hull was resting served as the electrolyte. After identifying the source of the trouble, the Ames engineer provided a solution: a new wire-and-rod grounding system made of aluminum like the ferry's hull so there would no longer be dissimilar metals in contact. Ames research on the matter disclosed that the problem was not unique to the Golden Gate ferries. It is being experienced by many pleasure boat operators who are probably as puzzled about it as was the Golden Gate Transit Authority.

  17. Underground pipeline corrosion control

    SciTech Connect

    Gundry, R.D.

    1988-04-01

    In the past few years, the pipeline corrosion control industry has been shaken by several catastrophic pipeline failures attributed to corrosion. Reports of corrosion-related failures seem to be on the rise, and this has caused the industry to reassess the criteria for cathodic protection and the correct application of the criteria. The US Congress and many state legislatures are also asking questions about pipeline safety. Several pieces of legislation are proposed to improve pipeline safety. NACE Task Group T-10-1 is in the process of revising Standard RP0169. Field data have been solicited from industry and are being analyzed. The committee has reviewed an extensive compilation of articles written over the last 50 years to evaluate the existing document. The committee is also awaiting the issuance of an Interim Report from the American Gas Association on the effectiveness of the criteria. The report is to present data obtained from several field test sites from around the country.

  18. 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.

  19. Corrosion resistant PEM fuel cell

    DOEpatents

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

  20. 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.

  1. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard [Honeoye Falls, NY; Borup, Rodney Lynn [East Rochester, NY; Hulett, Jay S [Rochester, NY; Brady, Brian K. NY; Cunningham, Kevin M [Romeo, MI

    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.

  2. In-situ monitoring of undercoating corrosion damage by Direct Optical Interrogation (DOI)

    NASA Astrophysics Data System (ADS)

    Lopez-Garrity, Meng

    topcoat dramatically reduces undercoating corrosion and masks many deficiencies of a conversion coating or primer. DOI was used to compare undercoating corrosion that developed due to exposure in ASTM B117, ASTM G85-A5 and outdoor environments. Similar corrosion morphologies developed in ASTM B117 and static immersion exposures. A single and stable corrosions site nucleated and propagated with a filamentary morphology. In general, salt spray exposure was more aggressive than static immersion. ASTM G85-A5 exposure produced different corrosion morphologies. Corrosion sites were round rather than filamentary. Massive nucleation of small corrosion sites across the whole surface also occurred. ASTM G85 environment was mild compared with the ASTM B117 and static immersion exposures. In outdoor exposure testing carried out for 5 months, no signs of corrosion was observed. To assess the extent to which oxygen reduction occurring on the coated surface supported corrosion site growth, a universal pH indicator was added to agar gels or PVB coatings applied on top of metallizations. Color changes indicating pH changes associated with local alkalization or acidification due to local cell action were assessed visually. Overall, the evidence is consistent with the idea that both hydrogen reduction and oxygen reduction support local corrosion site growth. In practical embodiments of corrosion protection, every effort should be made to restrict oxygen reduction to slow corrosion growth rates.

  3. An approach for the delineation of a generic cut-off value for local respiratory tract irritation by irritating or corrosive substances as a pragmatic tool to fulfill REACH requirements.

    PubMed

    Messinger, H

    2014-04-01

    Under the current European legislation for the Registration, Evaluation, Authorisation and restriction of Chemicals (REACHs) a Derived No Effect Level (DNEL) has to be delineated for acute and chronic inhalation effects. The majority of available experimental studies are performed by the oral route of exposure. Route to route extrapolation poses particular problems for irritating or corrosive substances but the necessity for additional animal studies with inhalation exposure needs to be balanced with the regulatory information requirements. Existing occupational exposure limits (OEL) as surrogate for cut-off limits representing safe exposure under working conditions were grouped under certain criteria for substances that are legally classified in Europe as irritating or corrosive. As a result, it was shown that the OEL for irritating substances in this dataset is not lower than 10mg/m(3) and for corrosives not lower than 1mg/m(3). Under certain conditions these generic limits could be applied as a pragmatic, but still sufficiently reliable and protective upper cut-off limit approach to avoid additional animal tests with irritating or corrosive chemicals. The respective systemic toxicity profiles and physical-chemical properties need to be considered. Specific exclusion criteria for the discussed concept apply.

  4. Management of Gustilo Anderson III B open tibial fractures by primary fascio-septo-cutaneous local flap and primary fixation: The ‘fix and shift’ technique

    PubMed Central

    Ramasamy, P R

    2017-01-01

    Background: Open fractures of tibia have posed great difficulty in managing both the soft tissue and the skeletal components of the injured limb. Gustilo Anderson III B open tibial fractures are more difficult to manage than I, II, and III A fractures. Stable skeletal fixation with immediate soft tissue cover has been the key to the successful outcome in treating open tibial fractures, in particular, Gustilo Anderson III B types. If the length of the open wound is larger and if the exposed surface of tibial fracture and tibial shaft is greater, then the management becomes still more difficult. Materials and Methods: Thirty six Gustilo Anderson III B open tibial fractures managed between June 2002 and December 2013 with “fix and shift” technique were retrospectively reviewed. All the 36 patients managed by this technique had open wounds measuring >5 cm (post debridement). Under fix and shift technique, stable fixation involved primary external fixator application or primary intramedullary nailing of the tibial fracture and immediate soft tissue cover involved septocutaneous shift, i.e., shifting of fasciocutaneous segments based on septocutaneous perforators. Results: Primary fracture union rate was 50% and reoperation rate (bone stimulating procedures) was 50%. Overall fracture union rate was 100%. The rate of malunion was 14% and deep infection was 16%. Failure of septocutaneous shift was 2.7%. There was no incidence of amputation. Conclusion: Management of Gustilo Anderson III B open tibial fractures with “fix and shift” technique has resulted in better outcome in terms of skeletal factors (primary fracture union, overall union, and time for union and malunion) and soft tissue factors (wound healing, flap failure, access to secondary procedures, and esthetic appearance) when compared to standard methods adopted earlier. Hence, “fix and shift” could be recommended as one of the treatment modalities for open III B tibial fractures. PMID:28216752

  5. 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…

  6. 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…

  7. The corrosion protection of 2219-T87 aluminum by anodizing

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1991-01-01

    Various types of anodizing coatings were studied for 2219-T87 aluminum. These include both type II and type III anodized coats which were water sealed and a newly developed and proprietary Magnaplate HCR (TM) coat. Results indicate that type II anodizing is not much superior to type II anodizing as far as corrosion protection for 2219-T87 aluminum is concerned. Magnaplate HCR (TM) coatings should provide superior corrosion protection over an extended period of time using a coating thickness of 51 microns (2.0 mils).

  8. Corrosion of barrier materials in seawater environments

    SciTech Connect

    Heiser, J.H.; Soo, P.

    1995-07-01

    A brief review has been carried out on the performance of barrier materials for low-level radioactive wastes in seawater environments. The environments include those for shallower coastal waters as well as the deep ocean (down to 3800 m). The review is mainly focused on metallic materials since they are the most common for seawater service and they have the largest data base. Information from the literature is usually pertinent to shallower coastal locations, but there is a valuable source of corrosion data obtained from several studies of metallic specimens exposed to ocean-bed conditions. In addition, the corrosion of carbon steel barriers has been evaluated for actual waste containers that were retrieved from previously-used disposal sites in the Atlantic and Pacific Oceans. Of the metallic materials studied, carbon steel showed the least corrosion resistance. Failure by non-uniform attack in a typical waste container could occur in as little as 25 y in some ocean environments ` Penetration by local attack, such as pitting and crevice corrosion resistance was also observed for more expensive materials such as low-alloy steels, stainless steels, titanium alloys, zirconium alloys, copper alloys, nickel alloys, aluminum alloys, and lead alloys.

  9. Corrosion behavior of aluminum-lithium alloys

    SciTech Connect

    Garrard, W.N. )

    1994-03-01

    Corrosion behavior of three aluminum-lithium (Al-Li) alloys was investigated in aerated 0.5 M sodium sulfate (Na[sub 2]SO[sub 4]), deaerated 3.5% sodium chloride (NaCl), and aerated 3.5% NaCl. Corrosion behavior of the Aluminum Association (AA) alloys 2090-T8E41 (UNS A92090, sheet), AA 8090-T851 (UNS A98090, sheet), and AA 8090-T82551 (UNS A98090, bar) was compared to behavior of the conventional AA 7075-T6 (UNS A97075, sheet). Uniform corrosion was the predominant form of attack in aerated Na[sub 2]SO[sub 4] and deaerated NaCl, although some localized attack resulted from corrosion of intermetallics on specimen surfaces. Pitting was the main form of attack in aerated NaCl. In all three media, the sheet materials corroded at a similar rate, but the bar form of AA 8090 corroded at a lower rate. Pretreatment of the alloys by immersion in a cerium (Ce) solution inhibited pitting in aerated NaCl but only for a short period.

  10. Corrosion and tribocorrosion of hafnium in simulated body fluids.

    PubMed

    Rituerto Sin, J; Neville, A; Emami, N

    2014-08-01

    Hafnium is a passive metal with good biocompatibility and osteogenesis, however, little is known about its resistance to wear and corrosion in biological environments. The corrosion and tribocorrosion behavior of hafnium and commercially pure (CP) titanium in simulated body fluids were investigated using electrochemical techniques. Cyclic polarization scans and open circuit potential measurements were performed in 0.9% NaCl solution and 25% bovine calf serum solution to assess the effect of organic species on the corrosion behavior of the metal. A pin-on-plate configuration tribometer and a three electrode electrochemical cell were integrated to investigate the tribocorrosion performance of the studied materials. The results showed that hafnium has good corrosion resistance. The corrosion density currents measured in its passive state were lower than those measured in the case of CP titanium; however, it showed a higher tendency to suffer from localized corrosion, which was more acute when imperfections were present on the surface. The electrochemical breakdown of the oxide layer was retarded in the presence of proteins. Tribocorrosion tests showed that hafnium has the ability to quickly repassivate after the oxide layer was damaged; however, it showed higher volumetric loss than CP titanium in equivalent wear-corrosion conditions. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1157-1164, 2014.

  11. Effect of the electrolyte composition on the corrosion of 12Kh17 steel in molten alkali metal carbonates

    NASA Astrophysics Data System (ADS)

    Nikitina, E. V.

    2017-02-01

    The corrosion of 12Kh17 steel in the melts of alkali metal carbonates containing additions of various chemical types is studied using anodic potentiostatic polarization. The morphology of the 12Kh17 steel surface is analyzed by electron-probe microanalysis. The introduction of corrosion passivators and activators affects the mechanism of local corrosion damages. The corrosion of the steel proceeds according to an electrochemical mechanism. Carbonate anions serve as oxidizers of the steel along with oxygen dissolved in the melt. Treatment of a corrosive medium can be used to protect metallic constructions against corrosion in high-temperature salt electrolytes. Combined introduction of corrosion activators and passivators in a salt phase makes it possible to form protective layers with a high corrosion resistance.

  12. Barnacle-induced corrosion of high-alloyed steels

    SciTech Connect

    Koryakova, M.D.; Filonenko, N.Yu.; Kaplin, Yu.M.

    1995-03-01

    Local corrosion of two sorts of high-alloyed steels under the action of acorn barnacles (Balanuses) has been studied. It has been shown that in natural seawater at anaerobic conditions beneath living and dead barnacles, metabolic activity of bacteria may be considered as a primary cause for local surface depassivation.

  13. Microbiologically influenced corrosion: looking to the future.

    PubMed

    Videla, Héctor A; Herrera, Liz K

    2005-09-01

    This review discusses the state-of-the-art of research into biocorrosion and the biofouling of metals and alloys of industrial usage. The key concepts needed to understand the main effects of microorganisms on metal decay, and current trends in monitoring and control strategies to mitigate the deleterious effects of biocorrosion and biofouling are also described. Several relevant cases of biocorrosion studied by our research group are provided as examples: (i) biocorrosion of aluminum and its alloys by fungal contaminants of jet fuels; (ii) sulfate-reducing bacteria (SRB)-induced corrosion of steel; (iii) biocorrosion and biofouling interactions in the marine environment; (iv) monitoring strategies for assessing biocorrosion in industrial water systems; (v) microbial inhibition of corrosion; (vi) use and limitations of electrochemical techniques for evaluating biocorrosion effects. Future prospects in the field are described with respect to the potential of innovative techniques in microscopy (environmental scanning electron microscopy, confocal scanning laser microscopy, atomic force microscopy), new spectroscopic techniques for the study of corrosion products and biofilms (energy dispersion X-ray analysis, X-ray photoelectron spectroscopy, electron microprobe analysis) and electrochemistry (electrochemical impedance spectroscopy, electrochemical noise analysis).

  14. Neurodevelopmental outcome of Italian preterm children at 1year of corrected age by Bayley-III scales: An assessment using local norms.

    PubMed

    Gasparini, Corinna; Caravale, Barbara; Rea, Monica; Coletti, Maria Franca; Tonchei, Valentina; Bucci, Silvia; Dotta, Andrea; De Curtis, Mario; Gentile, Simonetta; Ferri, Rosa

    2017-07-08

    Premature birth is often associated with neurodevelopmental difficulties throughout childhood. In the first three years of life, the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) constitute one of the most used tools for assessing child development. Since Bayley-III original norms are based on United States (US) population, it remains uncertain whether their use in other countries (e.g., European) is appropriate. This research aimed to examine neurodevelopment of preterm infants and full-term infants, using Bayley-III US norms in comparison to Italian (IT) norms. Patterns of developmental outcomes for both infant groups were also explored. 104 preterm and 58 full-term infants were included in the study. Bayley-III was used for neurodevelopmental assessment at 1year of corrected age, considering both IT and US norms for scores computation. Comparing scores obtained with IT vs US norms, differences in means were all significant across five subscales (p<0.05 at least) for preterm infants, whereas for full-term peers significant differences were found only for Receptive Language and Fine Motor subscales (p<0.001). Effect size (η(2)) ranged from 0.22 to 0.94. Within each group, significant discrepancies across subscales were found. Moreover, Italian preterm infants had significantly lower performances than full-term peers, excepting for Expressive Language and Gross Motor subscales. As regards to Italian 1-year children, our study seems to provide evidence for the tendency of Bayley-III US norms to overestimate development compared to IT norms. These findings emphasize the need to early detect children at risk for developmental delay and to plan early intervention. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Corrosion protection by anaerobiosis.

    PubMed

    Volkland, H P; Harms, H; Wanner; Zehnder, A J

    2001-01-01

    Biofilm-forming bacteria can protect mild (unalloyed) steel from corrosion. Mild steel coupons incubated with Rhodoccocus sp. strain C125 and Pseudomonas putida mt2 in an aerobic phosphate-buffered medium containing benzoate as carbon and energy source, underwent a surface reaction leading to the formation of a corrosion-inhibiting vivianite layer [Fe3(PO4)2]. Electrochemical potential (E) measurements allowed us to follow the buildup of the vivianite cover. The presence of sufficient metabolically active bacteria at the steel surface resulted in an E decrease to -510 mV, the potential of free iron, and a continuous release of ferrous iron. Part of the dissolved iron precipitated as vivianite in a compact layer of two to three microns in thickness. This layer prevented corrosion of mild steel for over two weeks, even in a highly corrosive medium. A concentration of 20 mM phosphate in the medium was found to be a prerequisite for the formation of the vivianite layer.

  16. Underground corrosion control

    SciTech Connect

    Not Available

    1993-01-01

    Corrosion of underground metallic structures continues to be a crucial concern within society and the engineering community. Costs associated with corrosion losses are staggering. Indirect costs associated with environmental damage as well as loss of public confidence has in many cases out-stripped direct costs for facility repair and replacement. NACE Group Committee T-10, responsible for the study and advancement of technology necessary for engineering solutions for underground corrosion problems, is divided into five key unit committees as follows: cathodic protection; interference problems; electric power and communications; protective coating systems; and internal corrosion of pipelines. The papers presented in this publication reflect the most recent developments in field practice in all five areas. Cathodic protection criteria, protection of pipelines, tanks and pilings, test methods, transit systems investigations, power and communication cables, and compliance with regulations are addressed. Interference testing, refinery problems, methods of safely mitigating the effects of induced AC on pipelines, and experience with alternate engineering materials such as prestressed concrete cylinder pipe and ductile iron pipe are included. All 37 papers have been processed separately for inclusion on the data base.

  17. COPPER CORROSION RESEARCH UPDATE

    EPA Science Inventory

    Copper release and corrosion related issues continue to be important to many water systems. The objective of this presentation is to discuss the current state of copper research at the USEPA. Specifically, the role of aging on copper release, use of phosphates for copper corrosio...

  18. NAVAIR Corrosion Overview

    DTIC Science & Technology

    2009-02-01

    Cleaning Efficiency • Hydrogen Embrittlement •Corrosion Testing •Storage Stability (1 & 2 year extended) •Pump Bottles, 5 gal pail, 55 gal drum 20...Technology - Materials Protection Advanced Polymers and Composites  NDI Functional materials IN-SERVICE ENGINEERING/PRODUCTION SUPPORT • FRC/ISSC Engineering

  19. Corrosion resistant cemented carbide

    SciTech Connect

    Hong, J.

    1990-10-16

    This paper describes a corrosion resistant cemented carbide composite. It comprises: a granular tungsten carbide phase, a semi-continuous solid solution carbide phase extending closely adjacent at least a portion of the grains of tungsten carbide for enhancing corrosion resistance, and a substantially continuous metal binder phase. The cemented carbide composite consisting essentially of an effective amount of an anti-corrosion additive, from about 4 to about 16 percent by weight metal binder phase, and with the remaining portion being from about 84 to about 96 percent by weight metal carbide wherein the metal carbide consists essentially of from about 4 to about 30 percent by weight of a transition metal carbide or mixtures thereof selected from Group IVB and of the Periodic Table of Elements and from about 70 to about 96 percent tungsten carbide. The metal binder phase consists essentially of nickel and from about 10 to about 25 percent by weight chromium, the effective amount of an anti-corrosion additive being selected from the group consisting essentially of copper, silver, tine and combinations thereof.

  20. Smart Coatings for Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Li, Wendy; Buhrow, Jerry W.; Johnsey, Marissa N.

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. 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.

  1. High-Performance Corrosion-Resistant Iron-Based Amorphous Metals: The Effects of Composition, Structure and Environment on Corrosion Resistance

    SciTech Connect

    Farmer, J; Choi, J S; Haslam, J; Lian, T; Day, S; Yang, N; Blue, C; Peters, W; Bayles, R; Lewandowski, J; Perepezko, J; Hildal, K; Lavernia, E; Ajdelsztajn, A; Grave, O; Aprigliano, L; Kaufman, L; Boudreau, J; Branagan, D J; Beardsley, B

    2006-04-11

    New corrosion-resistant, iron-based amorphous metals have been identified from published data or developed through combinatorial synthesis, and tested to determine their relative thermal phase stability, microstructure, mechanical properties, damage tolerance, and corrosion resistance. Some alloy additions are known to promote glass formation and to lower the critical cooling rate [F. Guo, S. J. Poon, Applied Physics Letters, 83 (13) 2575-2577, 2003]. Other elements are known to enhance the corrosion resistance of conventional stainless steels and nickel-based alloys [A. I. Asphahani, Materials Performance, Vol. 19, No. 12, pp. 33-43, 1980] and have been found to provide similar benefits to iron-based amorphous metals. Many of these materials can be cast as relatively thick ingots, or applied as coatings with advanced thermal spray technology. A wide variety of thermal spray processes have been developed by industry, and can be used to apply these new materials as coatings. Any of these can be used for the deposition of the formulations discussed here, with varying degrees of residual porosity and crystalline structure. Thick protective coatings have now been made that are fully dense and completely amorphous in the as-sprayed condition. An overview of the High-Performance Corrosion Resistant Materials (HPCRM) Project will be given, with particular emphasis on the corrosion resistance of several different types of iron-based amorphous metals in various environments of interest. The salt fog test has been used to compare the performance of various wrought alloys, melt-spun ribbons, arc-melted drop-cast ingots, and thermal-spray coatings for their susceptibility to corrosion in marine environments. Electrochemical tests have also been performed in seawater. Spontaneous breakdown of the passive film and localized corrosion require that the open-circuit corrosion potential exceed the critical potential. The resistance to localized corrosion is seawater has been

  2. SAGE III

    Atmospheric Science Data Center

    2017-01-13

    SAGE III Data and Information The Stratospheric Aerosol and Gas ... on the spacecraft. SAGE III produced L1 and L2 scientific data from 5/07/2002 until 12/31/2005. The flight of the second instrument is as ... Additional Info:  Data Format: HDF-EOS or Big Endian/IEEE Binary SCAR-B Block:  ...

  3. Corrosion monitoring along infrastructures using distributed fiber optic sensing

    NASA Astrophysics Data System (ADS)

    Alhandawi, Khalil B.; Vahdati, Nader; Shiryayev, Oleg; Lawand, Lydia

    2016-04-01

    Pipeline Inspection Gauges (PIGs) are used for internal corrosion inspection of oil pipelines every 3-5 years. However, between inspection intervals, rapid corrosion may occur, potentially resulting in major accidents. The motivation behind this research project was to develop a safe distributed corrosion sensor placed inside oil pipelines continuously monitoring corrosion. The intrinsically safe nature of light provided motivation for researching fiber optic sensors as a solution. The sensing fiber's cladding features polymer plastic that is chemically sensitive to hydrocarbons within crude oil mixtures. A layer of metal, used in the oil pipeline's construction, is deposited on the polymer cladding, which upon corrosion, exposes the cladding to surrounding hydrocarbons. The hydrocarbon's interaction with the cladding locally increases the cladding's refractive index in the radial direction. Light intensity of a traveling pulse is reduced due to local reduction in the modal capacity which is interrogated by Optical Time Domain Reflectometery. Backscattered light is captured in real-time while using time delay to resolve location, allowing real-time spatial monitoring of environmental internal corrosion within pipelines spanning large distances. Step index theoretical solutions were used to calculate the power loss due changes in the intensity profile. The power loss is translated into an attenuation coefficient characterizing the expected OTDR trace which was verified against similar experimental results from the literature. A laboratory scale experiment is being developed to assess the validity of the model and the practicality of the solution.

  4. Flow-induced corrosion of absorbable magnesium alloy: In-situ and real-time electrochemical study

    PubMed Central

    Wang, Juan; Jang, Yongseok; Wan, Guojiang; Giridharan, Venkataraman; Song, Guang-Ling; Xu, Zhigang; Koo, Youngmi; Qi, Pengkai; Sankar, Jagannathan; Huang, Nan; Yun, Yeoheung

    2016-01-01

    An in-situ and real-time electrochemical study in a vascular bioreactor was designed to analyze corrosion mechanism of magnesium alloy (MgZnCa) under mimetic hydrodynamic conditions. Effect of hydrodynamics on corrosion kinetics, types, rates and products was analyzed. Flow-induced shear stress (FISS) accelerated mass and electron transfer, leading to an increase in uniform and localized corrosions. FISS increased the thickness of uniform corrosion layer, but filiform corrosion decreased this layer resistance at high FISS conditions. FISS also increased the removal rate of localized corrosion products. Impedance-estimated and linear polarization-measured polarization resistances provided a consistent correlation to corrosion rate calculated by computed tomography. PMID:28626241

  5. Corrosion behavior of materials exposed to hypersaline geothermal brine

    SciTech Connect

    McCright, R.D.

    1980-11-20

    The corrosion rate and corrosion attack characteristics were determined for thirteen commercially available materials exposed in a geothermal production well for three months. The materials included carbon steels, Cr-Mo alloy steels, martensitic and ferritic stainless steels, high-nickel alloys, and titanium. The environment at the 1800 ft (600 m) depth of exposure was a single phase high salinity brine. The prevailing temperature was 260{sup 0}C and the prevailing pressure was 630 psi (4.0 MPa) during the exposure period. Results indicated that the carbon steels suffered intense generalized and localized corrosion. Addition of Cr and Mo to steels imparted significant improvement in the corrosion performance in this aggressive environment. Of the stainless steels tested, the most resistant were those containing a few percent molybdenum.

  6. Crevice and pitting corrosion behavior of stainless steels in seawater

    SciTech Connect

    Zaragoza-Ayala, A.E.; Orozco-Cruz, R.

    1999-11-01

    Pitting and crevice corrosion tests in natural seawater were performed on a series of stainless steels (i.e., S31603, N08904, S32304, S31803, S32520, N08925 and S31266) in order to determine their resistance to these types of localized corrosion. Open circuit potential (OCP) measurements for these alloys show for short exposure times an ennoblement in the OCP. After a certain time, occasional fall and rise in the OCP values was observed, which can be related to nucleation and repassivation of pits and/or crevices on the metal surface. Analysis of the electrochemical behavior and microscopic observations shows that only S31603 and S32304 alloys were susceptible to crevice and pitting corrosion, whereas the remaining alloys exhibited good resistance. Pitting potentials determined by the potentiodynamic technique also show S3 1603 and S32304 are susceptible to pitting corrosion under the experimental conditions used in this work.

  7. Sensitivity Analysis of Corrosion Rate Prediction Models Utilized for Reinforced Concrete Affected by Chloride

    NASA Astrophysics Data System (ADS)

    Siamphukdee, Kanjana; Collins, Frank; Zou, Roger

    2013-06-01

    Chloride-induced reinforcement corrosion is one of the major causes of premature deterioration in reinforced concrete (RC) structures. Given the high maintenance and replacement costs, accurate modeling of RC deterioration is indispensable for ensuring the optimal allocation of limited economic resources. Since corrosion rate is one of the major factors influencing the rate of deterioration, many predictive models exist. However, because the existing models use very different sets of input parameters, the choice of model for RC deterioration is made difficult. Although the factors affecting corrosion rate are frequently reported in the literature, there is no published quantitative study on the sensitivity of predicted corrosion rate to the various input parameters. This paper presents the results of the sensitivity analysis of the input parameters for nine selected corrosion rate prediction models. Three different methods of analysis are used to determine and compare the sensitivity of corrosion rate to various input parameters: (i) univariate regression analysis, (ii) multivariate regression analysis, and (iii) sensitivity index. The results from the analysis have quantitatively verified that the corrosion rate of steel reinforcement bars in RC structures is highly sensitive to corrosion duration time, concrete resistivity, and concrete chloride content. These important findings establish that future empirical models for predicting corrosion rate of RC should carefully consider and incorporate these input parameters.

  8. Stress-corrosion cracking in equiaxed 7075

    NASA Astrophysics Data System (ADS)

    Thompson, Anthony W.; Mueller, Matthias P.; Bernstein, I. M.

    1993-11-01

    The environmental response of commercially produced high-strength Al alloys, such as 7075, depends strongly on the anisotropy of the grain structure. Minimum resistance to both stresscorrosion cracking (SCC) and hydrogen embrittlement is observed in the short transverse direction of the “pancake” grain structure in commercially produced alloys. It has not been established, however, exactly how the morphology of the grain structure mediates the SCC response or the SCC mechanism. Therefore, stress-corrosion testing of a high-purity 7075 Al alloy (low in Fe, Si, and Cr), having equiaxed grains, under tension (mode I) and torsion (mode III) loading in a solution of IN A1C13 has been performed. The SCC results in the two loading modes, including fractography, appeared to suggest that the predominant processes of SCC were hydrogen embrittlement in mode I and anodic dissolution in mode III, in agreement with prior work on a commercially produced 7075 alloy, but that severe corrosion during longer tests renders those results unsuitable for threshold determination in this very aggressive testing environment.

  9. The corrosion and stress corrosion cracking behavior of a novel alumina-forming austenitic stainless steel in supercritical water

    NASA Astrophysics Data System (ADS)

    Sun, Hongying; Yang, Haijie; Wang, Man; Giron-Palomares, Benjamin; Zhou, Zhangjian; Zhang, Lefu; Zhang, Guangming

    2017-02-01

    The general corrosion and stress corrosion behavior of Fe-27Ni-15Cr-5Al-2Mo-0.4Nb alumina-forming austenitic (AFA) steel were investigated in supercritical water under different conditions. A double layer oxide structure was formed: a Fe-rich outer layer (Fe2O3 and Fe3O4) and an Al-Cr-rich inner layer. And the inner layer has a low growth rate with exposing time, which is good for improvement of corrosion resistance. Additionally, some internal nodular Al-Cr-rich oxides were also observed, which resulted in a local absence of inner layer. Stress corrosion specimens exhibited a combination of high strength, good ductility and low susceptibility. The stress strength and elongation was reduced by increasing temperature and amount of dissolved oxygen. In addition, the corresponding susceptibility was increased with decreased temperatures and increased oxygen contents.

  10. Oxidation and Corrosion of Ceramics and Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Jacobson, Nathan S.; Opila, Elizabeth J.; Lee, Kang N.

    2000-01-01

    Ceramics and ceramic matrix composites are candidates for numerous applications in high temperature environments with aggressive gases and possible corrosive deposits. There is a growing realization that high temperature oxidation and corrosion issues must be considered. There are many facets to these studies, which have been extensively covered in some recent reviews. The focus of this paper is on current research, over the past two years. In the authors' view, the most important oxidation and corrosion studies have focused on four major areas during this time frame. These are; (I) Oxidation of precursor-based ceramics; (II) Studies of the interphase material in ceramic matrix composites; (III) Water vapor interactions with ceramics, particularly in combustion environments; and (IV) Development of refractory oxide coatings for silicon-based ceramics. In this paper, we shall explore the most current work in each of these areas.

  11. Simulation of Fatigue Crack Initiation at Corrosion Pits With EDM Notches

    NASA Technical Reports Server (NTRS)

    Smith, Stephen W.; Newman, John A.; Piascik, Robert S.

    2003-01-01

    Uniaxial fatigue tests were conducted to compare the fatigue life of laboratory produced corrosion pits, similar to those observed in the shuttle main landing gear wheel bolt-hole, and an electro-discharged-machined (EDM) flaw. EDM Jaws are used to simulate corrosion pits during shuttle wheel (dynamometer) testing. The aluminum alloy, (AA 7050) laboratory fatigue tests were conducted to simulate the local stress level contained in the wheel bolt-hole. Under this high local stress condition, the EDM notch produced a fatigue life similar to test specimens containing corrosion pits of similar size. Based on the laboratory fatigue test results, the EDM Jaw (semi-circular disc shaped) produces a local stress state similar to corrosion pits and can be used to simulate a corrosion pit during the shuttle wheel dynamometer tests.

  12. Atmospheric corrosion of lithium electrodes

    SciTech Connect

    Johnson, C.J.

    1981-10-01

    Atmospheric corrosion of lithium during lithium-cell assembly and the dry storage of cells prior to electrolyte fill has been found to initiate lithium corrosion pits and to form corrosion products. Scanning Electron Microscopy (SEM) was used to investigate lithium pitting and the white floccullent corrosion products. Electron Spectroscopy for Chemical Analysis (ESCA) and Auger spectroscopy in combination with X-ray diffraction were used to characterize lithium surfaces. Lithium surfaces with corrosion products were found to be high in carbonate content indicating the presence of lithium carbonate. Lithium electrodes dry stored in unfilled batteries were found to contain high concentration of lithium flouride a possible corrosion product from gaseous materials from the carbon monofluoride cathode. Future investigations of the corrosion phenomena will emphasize the effect of the corrosion products on the electrolyte and ultimate battery performance. The need to protect lithium electrodes from atmospheric exposure is commonly recognized to minimize corrosion induced by reaction with water, oxygen, carbon dioxide or nitrogen (1). Manufacturing facilities customarily limit the relative humidity to less than two percent. Electrodes that have been manufactured for use in lithium cells are typically stored in dry-argon containers. In spite of these precautions, lithium has been found to corrode over a long time period due to residual gases or slow diffusion of the same into storage containers. The purpose of this investigation was to determine the nature of the lithium corrosion.

  13. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    SciTech Connect

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  14. 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.

  15. A Dibasic Amino Acid Pair Conserved in the Activation Loop Directs Plasma Membrane Localization and Is Necessary for Activity of Plant Type I/II Phosphatidylinositol Phosphate Kinase1[W

    PubMed Central

    Mikami, Koji; Saavedra, Laura; Hiwatashi, Yuji; Uji, Toshiki; Hasebe, Mitsuyasu; Sommarin, Marianne

    2010-01-01

    Phosphatidylinositol phosphate kinase (PIPK) is an enzyme involved in the regulation of cellular levels of phosphoinositides involved in various physiological processes, such as cytoskeletal organization, ion channel activation, and vesicle trafficking. In animals, research has focused on the modes of activation and function of PIPKs, providing an understanding of the importance of plasma membrane localization. However, it still remains unclear how this issue is regulated in plant PIPKs. Here, we demonstrate that the carboxyl-terminal catalytic domain, which contains the activation loop, is sufficient for plasma membrane localization of PpPIPK1, a type I/II B PIPK from the moss Physcomitrella patens. The importance of the carboxyl-terminal catalytic domain for plasma membrane localization was confirmed with Arabidopsis (Arabidopsis thaliana) AtPIP5K1. Our findings, in which substitution of a conserved dibasic amino acid pair in the activation loop of PpPIPK1 completely prevented plasma membrane targeting and abolished enzymatic activity, demonstrate its critical role in these processes. Placing our results in the context of studies of eukaryotic PIPKs led us to conclude that the function of the dibasic amino acid pair in the activation loop in type I/II PIPKs is plant specific. PMID:20427464

  16. Atomic level characterization in corrosion studies

    NASA Astrophysics Data System (ADS)

    Marcus, Philippe; Maurice, Vincent

    2017-06-01

    Atomic level characterization brings fundamental insight into the mechanisms of self-protection against corrosion of metals and alloys by oxide passive films and into how localized corrosion is initiated on passivated metal surfaces. This is illustrated in this overview with selected data obtained at the subnanometre, i.e. atomic or molecular, scale and also at the nanometre scale on single-crystal copper, nickel, chromium and stainless steel surfaces passivated in well-controlled conditions and analysed in situ and/or ex situ by scanning tunnelling microscopy/spectroscopy and atomic force microscopy. A selected example of corrosion modelling by ab initio density functional theory is also presented. The discussed aspects include the surface reconstruction induced by hydroxide adsorption and formation of two-dimensional (hydr)oxide precursors, the atomic structure, orientation and surface hydroxylation of three-dimensional ultrathin oxide passive films, the effect of grain boundaries in polycrystalline passive films acting as preferential sites of passivity breakdown, the differences in local electronic properties measured at grain boundaries of passive films and the role of step edges at the exposed surface of oxide grains on the dissolution of the passive film. This article is part of the themed issue 'The challenges of hydrogen and metals'.

  17. Atomic level characterization in corrosion studies.

    PubMed

    Marcus, Philippe; Maurice, Vincent

    2017-07-28

    Atomic level characterization brings fundamental insight into the mechanisms of self-protection against corrosion of metals and alloys by oxide passive films and into how localized corrosion is initiated on passivated metal surfaces. This is illustrated in this overview with selected data obtained at the subnanometre, i.e. atomic or molecular, scale and also at the nanometre scale on single-crystal copper, nickel, chromium and stainless steel surfaces passivated in well-controlled conditions and analysed in situ and/or ex situ by scanning tunnelling microscopy/spectroscopy and atomic force microscopy. A selected example of corrosion modelling by ab initio density functional theory is also presented. The discussed aspects include the surface reconstruction induced by hydroxide adsorption and formation of two-dimensional (hydr)oxide precursors, the atomic structure, orientation and surface hydroxylation of three-dimensional ultrathin oxide passive films, the effect of grain boundaries in polycrystalline passive films acting as preferential sites of passivity breakdown, the differences in local electronic properties measured at grain boundaries of passive films and the role of step edges at the exposed surface of oxide grains on the dissolution of the passive film.This article is part of the themed issue 'The challenges of hydrogen and metals'. © 2017 The Author(s).

  18. Fatigue in the Presence of Corrosion (Fatigue sous corrosion)

    DTIC Science & Technology

    1999-03-01

    examines the embrittlement of high strength steels from corrosion, the loss in elongation and energy density was because of hydrogen absorption. This...1996. R.F. Heheman (eds.), Hydrogen [23] G.N. Haidemenopoulos, N. Hassiotis, Embrittlement and Stress G. Papapolymerou and Corrosion Cracking, Materials...corrosion fatigue hydrogen embrittlement because the diffusion cracks take over, the propagating flaw is a of Hydrogen would be at saturation. On the hybrid

  19. Environmental Considerations in the Studies of Corrosion Resistant Alloys for High-Level Radioactive Waste Containment

    SciTech Connect

    Ilevbare, G O; Lian, T; Farmer, J C

    2001-11-26

    The corrosion resistance of Alloy 22 (UNS No.: N06022) was studied in simulated ground water of different pH values and ionic contents at various temperatures. Potentiodynamic polarization techniques were used to study the electrochemical behavior and measure the critical potentials in the various systems. Alloy 22 was found to be resistant to localized corrosion in the simulated ground waters tested.

  20. Corrosion properties of powder bed fusion additively manufactured 17-4 PH stainless steel

    DOE PAGES

    Schaller, Rebecca; Taylor, Jason; Rodelas, Jeffrey; ...

    2017-02-18

    The corrosion susceptibility of a laser powder bed fusion (LPBF) additively manufactured alloy, UNS S17400 (17-4 PH), was explored compared to conventional wrought material. Microstructural characteristics were characterized and related to corrosion behavior in quiescent, aqueous 0.6 M NaCl solutions. Electrochemical measurements demonstrated that the LPBF 17-4 PH alloy exhibited a reduced passivity range and active corrosion compared to its conventional wrought counterpart. Lastly, a micro-electrochemical cell was employed to further understand the effects of the local scale and attributed the reduced corrosion resistance of the LPBF material to pores with diameters ≥ 50 µm.

  1. Numerical simulation of monitoring corrosion in reinforced concrete based on ultrasonic guided waves.

    PubMed

    Zheng, Zhupeng; Lei, Ying; Xue, Xin

    2014-01-01

    Numerical simulation based on finite element method is conducted to predict the location of pitting corrosion in reinforced concrete. Simulation results show that it is feasible to predict corrosion monitoring based on ultrasonic guided wave in reinforced concrete, and wavelet analysis can be used for the extremely weak signal of guided waves due to energy leaking into concrete. The characteristic of time-frequency localization of wavelet transform is adopted in the corrosion monitoring of reinforced concrete. Guided waves can be successfully used to identify corrosion defects in reinforced concrete with the analysis of suitable wavelet-based function and its scale.

  2. Millimeter Wave Nondestructive Evaluation of Corrosion Under Paint in Steel Structures

    SciTech Connect

    Kharkovsky, S.; Zoughi, R.

    2006-03-06

    Millimeter wave nondestructive evaluation techniques have shown great potential for detection of corrosion under paint in steel structures. They may also provide for detection of other anomalies associated with the corrosion process such as precursor pitting. This paper presents the results of an extensive investigation spanning a frequency range of 30-100 GHz and using magnitude- and phase-sensitive reflectometers. Using 2D automated scanning mechanisms, raster images of two corrosion patches are produced showing the spatial resolution capabilities of these systems as well as their potential for evaluating localized corrosion severity.

  3. Pitting and crevice corrosion of stainless steels in ammonium chloride solutions

    SciTech Connect

    Forsen, O.; Aromaa, J.; Virtanen, J.; Tavi, M.

    1995-09-01

    Carbon steel is the most commonly used construction material in oil refining. Ammonium chloride deposition is a well known problem in oil refining. When these deposits form in a moist environment, they are corrosive to carbon steel. When unexpected corrosion problems are faced the material is often changed zn to alloys like stainless steels. The main drawback of stainless steels is that they are prone to different forms of localized corrosion, especially in the presence of halides. In this paper the use of electrochemical measurements to study the corrosion resistance of stainless steels is discussed.

  4. Numerical Simulation of Monitoring Corrosion in Reinforced Concrete Based on Ultrasonic Guided Waves

    PubMed Central

    Zheng, Zhupeng; Lei, Ying; Xue, Xin

    2014-01-01

    Numerical simulation based on finite element method is conducted to predict the location of pitting corrosion in reinforced concrete. Simulation results show that it is feasible to predict corrosion monitoring based on ultrasonic guided wave in reinforced concrete, and wavelet analysis can be used for the extremely weak signal of guided waves due to energy leaking into concrete. The characteristic of time-frequency localization of wavelet transform is adopted in the corrosion monitoring of reinforced concrete. Guided waves can be successfully used to identify corrosion defects in reinforced concrete with the analysis of suitable wavelet-based function and its scale. PMID:25013865

  5. 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

  6. Environmental and Geometrical Conditions to Sustain Crevice Corrosion in Alloy 22

    SciTech Connect

    Carranza, R M; Rodr?guez, M A; Rebak, R B

    2006-11-10

    Alloy 22 (N06022) is highly resistant to localized corrosion. Under aggressive environmental conditions Alloy 22 may be susceptible to crevice corrosion in hot chloride (Cl{sup -}) solutions. The objective of the present work was to explore the environmental and geometrical conditions for crevice corrosion to occur. Electrochemical tests were performed using PCA and prismatic mill annealed Alloy 22 specimens in chloride solutions. Crevice corrosion current density was found to be a function of applied potential. i{sub CREV} values ranged from 40 {micro}A/cm{sup 2} to 20 mA/cm{sup 2}. Such low values of current density explained the absence of pitting corrosion in Alloy 22 at any potential. Decreasing of the effective diffusion distance in a propagating crevice is thought to cause crevice corrosion stifling or repassivation after long anodic polarization. Crevice corrosion breakdown potential is expected to decrease with potential scan rate, approaching repassivation potential for low scan rates. The lowest corrosion potential of Alloy 22 in hydrochloric acid solutions at which active corrosion exists was proposed as the lowest possible repassivation potential for crevice corrosion.

  7. ARSENIC INTERACTION WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST: IMPLICATIONS FOR ARSENIC REMEDIATION

    EPA Science Inventory

    Zerovalent iron is being used in permeable reactive barriers (PRBs) to remediate groundwater arsenic contamination. Iron(II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron under anaerobic conditions. The interaction between arsenic and this green...

  8. ARSENIC INTERACTION WITH IRON (II, III) HYDROXYCARBONATE GREEN RUST: IMPLICATIONS FOR ARSENIC REMEDIATION

    EPA Science Inventory

    Zerovalent iron is being used in permeable reactive barriers (PRBs) to remediate groundwater arsenic contamination. Iron(II, III) hydroxycarbonate green rust is a major corrosion product of zerovalent iron under anaerobic conditions. The interaction between arsenic and this green...

  9. The Role of Hydrogen in the Stress Corrosion Cracking of High Strength Aluminum Alloys.

    DTIC Science & Technology

    1981-03-01

    effect. 2.5 Stress Corrosion Cracking of 7075 - Mode I/Mode III Testing Having obtained an understanding of the hydrogen embrittlement behavior of 7075 ...J. Albrecht, A. W. Thompson and I. M. Bernstein: "The Role of Microstruc - ture in Hydrogen-Assisted Fracture of 7075 Aluminum": Met. Trans. A, 1979...Thompson and I. M. Bernstein: "Effect of Microstruc - ture and Loading Mode on Stress Corrosion of 7075 Aluminum", in preparation. 12. R. E. Swanson, A. W

  10. BIOPLUME III

    EPA Pesticide Factsheets

    BIOPLUME III is a two-dimensional finite difference model for simulating the natural attenuation of organic contaminants in groundwater due to the processes of advection, dispersion, sorption, and biodegradation.

  11. 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.

  12. WASTE PACKAGE CORROSION STUDIES USING SMALL MOCKUP EXPERIMENTS

    SciTech Connect

    B.E. Anderson; K.B. Helean; C.R. Bryan; P.V. Brady; R.C. Ewing

    2005-10-19

    The corrosion of spent nuclear fuel and subsequent mobilization of radionuclides is of great concern in a geologic repository, particularly if conditions are oxidizing. Corroding A516 steel may offset these transport processes within the proposed waste packages at the Yucca Mountain Repository (YMR) by retaining radionuclides, creating locally reducing conditions, and reducing porosity. Ferrous iron, Fe{sup 2+}, has been shown to reduce UO{sub 2}{sup 2+} to UO{sub 2(s)} [1], and some ferrous iron-bearing ion-exchange materials adsorb radionuclides and heavy metals [2]. Of particular interest is magnetite, a potential corrosion product that has been shown to remove TcO{sub 4}{sup -} from solution [3]. Furthermore, if Fe{sup 2+} minerals, rather than fully oxidized minerals such as goethite, are produced during corrosion, then locally reducing conditions may be present. High electron availability leads to the reduction and subsequent immobilization of problematic dissolved species such as TcO{sub 4}{sup -}, NpO{sub 2}{sup +}, and UO{sub 2}{sup 2+} and can also inhibit corrosion of spent nuclear fuel. Finally, because the molar volume of iron material increases during corrosion due to oxygen and water incorporation, pore space may be significantly reduced over long time periods. The more water is occluded, the bulkier the corrosion products, and the less porosity is available for water and radionuclide transport. The focus of this paper is on the nature of Yucca Mountain waste package steel corrosion products and their effects on local redox state, radionuclide transport, and porosity.

  13. Probabilistic modeling of the corrosion of steel structures in marine water-development works

    SciTech Connect

    Bekker, A. T.; Lyubimov, V. S.; Kovalenko, R. G.; Aleksandrov, A. V.

    2011-09-15

    Considering that corrosion takes place as a random process over time, a a probabilistic approach was utilized in this paper. The corrosion of metallic sheet piling employed in the fascia wall of a bulwerk is considered as an example. A stochastic model is constructed on the base of a modified Weibull distribution function with consideration of parameters of the corrosion process as a function of time. One of the factors defining the corrosion rate of the sheet piling is the degree of access of a section of the wall to the zone of variable water level, or the underwater zone. The type of corrosion-continuous or local-is another factor. The accuracy of corrosion prediction in the underwater zone is higher than that in the zone of variable water level.

  14. Enhancement of corrosion resistance of carbon steel by Dioscorea Hispida starch in NaCl

    NASA Astrophysics Data System (ADS)

    Zulhusni, M. D. M.; Othman, N. K.; Lazim, Azwan Mat

    2015-09-01

    Starch is a one of the most abundant natural product in the world and has the potential as corrosion inhibitor replacing harmful synthetic chemical based corrosion inhibitor. This research was aimed to examines the potential of starch extracted from local Malaysian wild yam (Dioscorea hispida), as corrosion inhibitor to carbon steel in NaCl media replicating sea water. By using gravimetric test and analysis, in which the carbon steel specimens were immersed in NaCl media for 24, 48 and 60 hours with the starch as corrosion inhibitor. the corrosion rate (mmpy) and inhibition efficiencies (%) was calculated. The results obtained showed decrease in corrosion rate as higher concentration of starch was employed. The inhibition efficiencies also shows an increasing manner up to 95.97 % as the concentration of the inhibitor increased.

  15. Corrosion investigation of two materials for implant supraconstructions coupled to a titanium implant.

    PubMed

    Ravnholt, G; Jensen, J

    1991-04-01

    The corrosion of two materials for implant supraconstructions, a carbon fiber/PMMA composite and a silver-palladium alloy, was investigated in vitro, the materials being galvanically coupled to a titanium implant. Corrosion current and pH of the electrolyte were monitored, and corrosion products were identified by powder X-ray diffraction. The carbon composite and the silver-palladium per se did not corrode, whereas a silver-palladium specimen brazed with the recommended brazing alloy corroded unmistakably, yielding copper-containing corrosion products. The action of local corrosion cells around the brazed joint is considered, and it is concluded that the two materials seem well suited for implant supraconstructions, provided that brazing the silver-palladium can be avoided. Considering the clinical relevance of the experimental model used, it is concluded that the model is likely to predict a lower corrosion susceptibility than the one found in vivo.

  16. Vapor Corrosion Response of Low Carbon Steel Exposed to Simulated High Level Radioactive Waste

    SciTech Connect

    Wiersma, B

    2006-01-26

    A program to resolve the issues associated with potential vapor space corrosion and liquid/air interface corrosion in the Type III high level waste tanks is in place. The objective of the program is to develop understanding of vapor space (VSC) and liquid/air interface (LAIC) corrosion to ensure a defensible technical basis to provide accurate corrosion evaluations with regard to vapor space and liquid/air interface corrosion. The results of the FY05 experiments are presented here. The experiments are an extension of the previous research on the corrosion of tank steel exposed to simple solutions to corrosion of the steel when exposed to complex high level waste simulants. The testing suggested that decanting and the consequent residual species on the tank wall is the predominant source of surface chemistry on the tank wall. The laboratory testing has shown that at the boundary conditions of the chemistry control program for solutions greater than 1M NaNO{sub 3}{sup -}. Minor and isolated pitting is possible within crevices in the vapor space of the tanks that contain stagnant dilute solution for an extended period of time, specifically when residues are left on the tank wall during decanting. Liquid/air interfacial corrosion is possible in dilute stagnant solutions, particularly with high concentrations of chloride. The experimental results indicate that Tank 50 would be most susceptible to the potential for liquid/air interfacial corrosion or vapor space corrosion, with Tank 49 and 41 following, since these tanks are nearest to the chemistry control boundary conditions. The testing continues to show that the combination of well-inhibited solutions and mill-scale sufficiently protect against pitting in the Type III tanks.

  17. [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.

  18. 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%.

  19. 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.

  20. 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.

  1. 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.)

  2. 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.

  3. Microbiologically Influenced Corrosion

    DTIC Science & Technology

    2015-11-05

    types of bacteria to diag- nose and predict MIC, and an over interpretation of pit morphology to diagnose MIC [33]. In 2004, NACE International...of evolutionary descent, that is, bacteria , (methanogens), and eukaryota (fungi). The list of ’W<Jrganismls involved in MIC and the mechanisms by...enhanced erosion corrosion. However, microorganisms do not produce a unique con·osion morphology that distinguishes MIC from abiotically produced

  4. Accelerated Corrosion Testing

    DTIC Science & Technology

    1982-12-01

    conducted on high-strength 4340 steel and 7075-T6 aluminum alloy usina accelerating pollutants such as sulfur dinxide, nitrogen dioxide, surface salt...CONTROLLED 100 ATMOSPHERES APPiENDIX B - ACCELERATED ATMDSPHERIC-CORROSION TESTING 128 v I. LIST OF ILLUSTRATIONS Ficure Page 1 Schematic Diagram of Applied...Static-Load Crack-Growth Rate (from ref. 17). 26 12 Environmental-System Flow Diagram . 33 13 Compact-Tension Plane-Strain Fracture-Toughness Specimen

  5. 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.

  6. 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.

  7. Corrosion consultant expert system

    SciTech Connect

    Mo, Y.L.

    1994-12-31

    The development and use of an expert system to recommend coatings for flue gas desulfurization (FGD) plant is described. The system ranks coatings by their material properties, experimental test and plant performance scores when the component to be coated and its working environment are specified. The user interface, the inference engine, the knowledge base and the implementation of the expert system are presented with comments on its suitability and application for corrosion consultations.

  8. 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.

  9. 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.

  10. Corrosive wear principles

    SciTech Connect

    Schumacher, W.J.

    1993-12-31

    The dual effects of corrosion and wear operate together in such industries as paper and pulp, coal handling, mining, and sugar beet extraction. There is a synergistic effect that causes far greater wastage to carbon steels, alloy steels, and even much more abrasion resistant cast irons. Several laboratory and in situ studies have been conducted to better understand the contributions of corrosion and wear to the wastage process. The environmental conditions are usually set by the process. However, there are a few instances where inhibitors as sodium nitrite, sodium chromate, and sodium metasilicate have been successfully used to reduce metal wastage of carbon steels. Hardness has been found to be an unreliable guide to performance under wet sliding conditions. Heat treated alloy steels and cast irons are inferior to stainless steels. Even distilled water is too severe a corrodent for steels. While the austenitic stainlesses perform the best, cold rolling to increase hardness does not further improve their performance. The surface roughness of stainless steels gets smoother during corrosive wear testing while it gets rougher for the alloy steels. This observation substantiated the reputation of improved slideability for stainless alloys over alloy steels.

  11. 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/.

  12. High-level waste borosilicate glass: A compendium of corrosion characteristics. Volume 3

    SciTech Connect

    Cunnane, J.C.; Bates, J.K.; Bradley, C.R.

    1994-03-01

    The objective of this document is to summarize scientific information pertinent to evaluating the extent to which high-level waste borosilicate glass corrosion and the associated radionuclide release processes are understood for the range of environmental conditions to which waste glass may be exposed in service. Alteration processes occurring within the bulk of the glass (e.g., devitrification and radiation-induced changes) are discussed insofar as they affect glass corrosion. Volume III contains a bibliography of glass corrosion studies, including studies that are not cited in Volumes I and II.

  13. 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.

  14. 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.

  15. Vehicle Corrosion Expert System (CES)

    DTIC Science & Technology

    2000-07-19

    Report developed under SBlR contract for topic A99-092. This report describes the design and development of a vehicle Corrosion Expert System (CES). CES has immediate utility in the automotive industry by vehicle manufactures that have the...eliminate or reduce the expensive Accelerated Corrosion Testing phase of the new vehicle development effort. The Vehicle Corrosion Expert System supports...and level of detail required to allow the user to use the Expert System for his area of interest.

  16. 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.

  17. Corrosion Mitigation Strategies - an Introduction

    DTIC Science & Technology

    2009-02-05

    Control Technology – Cathodic protection – Corrosion inhibitors – Combination of methods • Balance cost and other factors Candidate Materials - Metals...Technology -UV, ozone,solvents,oxygen • Concrete -acids, chlorides, sulfates • Vitreous Materials-solvents • Corrosion Control • Waterproofing • Weather...Tar Enamel Leaders in Corrosion Control Technology – Tape – Concrete (Weight) Coating • Make metal to be protected act as a cathode • Application of

  18. Combined geochemical and electrochemical methodology to quantify corrosion of carbon steel by bacterial activity.

    PubMed

    Schütz, Marta K; Moreira, Rebeca; Bildstein, Olivier; Lartigue, Jean-Eric; Schlegel, Michel L; Tribollet, Bernard; Vivier, Vincent; Libert, Marie

    2014-06-01

    The availability of respiratory substrates, such as H2 and Fe(II,III) solid corrosion products within nuclear waste repository, will sustain the activities of hydrogen-oxidizing bacteria (HOB) and iron-reducing bacteria (IRB). This may have a direct effect on the rate of carbon steel corrosion. This study investigates the effects of Shewanella oneidensis (an HOB and IRB model organism) on the corrosion rate by looking at carbon steel dissolution in the presence of H2 as the sole electron donor. Bacterial effect is evaluated by means of geochemical and electrochemical techniques. Both showed that the corrosion rate is enhanced by a factor of 2-3 in the presence of bacteria. The geochemical experiments indicated that the composition and crystallinity of the solid corrosion products (magnetite and vivianite) are modified by bacteria. Moreover, the electrochemical experiments evidenced that the bacterial activity can be stimulated when H2 is generated in a small confinement volume. In this case, a higher corrosion rate and mineralization (vivianite) on the carbon steel surface were observed. The results suggest that the mechanism likely to influence the corrosion rate is the bioreduction of Fe(III) from magnetite coupled to the H2 oxidation.

  19. Computerized system for corrosion control

    SciTech Connect

    Hall, C. )

    1991-10-01

    This paper reports that computerization of basic corrosion measurements to provide record-keeping and graphical output has been used by pipeline companies over the lst decade. Northwest Pipeline Corp. has embarked on an ambition project to expand well beyond the scope of standard computer record-keeping by integrating data analysis and management with computer-aided advanced corrosion engineering practices. Most maturing pipeline systems require immense capital and maintenance expenditures to maintain regulatory levels of cathodic protection consistent with traditional corrosion control methods. Major pipeline coating rehabilitation programs and the installation of numerous anode-bed systems will continue in the absence of sophisticated computer-aided corrosion control methods.

  20. An In Vitro Comparison of PMMA and Calcium Sulfate as Carriers for the Local Delivery of Gallium(III) Nitrate to Staphylococcal Infected Surgical Sites

    PubMed Central

    Garcia, Rebecca A.; Tennent, David J.; Chang, David; Wenke, Joseph C.; Sanchez, Carlos J.

    2016-01-01

    Antibiotic-loaded bone cements, including poly(methyl methacrylate) (PMMA) and calcium sulfate (CaSO4), are often used for treatment of orthopaedic infections involving Staphylococcus spp., although the effectiveness of this treatment modality may be limited due to the emergence of antimicrobial resistance and/or the development of biofilms within surgical sites. Gallium(III) is an iron analog capable of inhibiting essential iron-dependent pathways, exerting broad antimicrobial activity against multiple microorganisms, including Staphylococcus spp. Herein, we evaluated PMMA and CaSO4 as carriers for delivery of gallium(III) nitrate (Ga(NO3)3) to infected surgical sites by assessing the release kinetics subsequent to incorporation and antimicrobial activity against S. aureus and S. epidermidis. PMMA and to a lesser extent CaSO4 were observed to be compatible as carriers for Ga(NO3)3, eluting concentrations with antimicrobial activity against planktonic bacteria, inhibiting bacterial growth, and preventing bacterial colonization of beads, and effective against established bacterial biofilms of S. aureus and S. epidermidis. Collectively, our in vitro results indicate that PMMA is a more suitable carrier compared to CaSO4 for delivery of Ga(NO3)3; moreover they provide evidence for the potential use of Ga(NO3)3 with PMMA as a strategy for the prevention and/or treatment for orthopaedic infections. PMID:26885514

  1. A Geobacter sulfurreducens Strain Expressing Pseudomonas aeruginosa Type IV Pili Localizes OmcS on Pili but Is Deficient in Fe(III) Oxide Reduction and Current Production

    PubMed Central

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S.; Nevin, Kelly P.; Vargas, Madeline

    2014-01-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity. PMID:24296506

  2. SHARE: a French multicenter phase III trial comparing accelerated partial irradiation versus standard or hypofractionated whole breast irradiation in breast cancer patients at low risk of local recurrence.

    PubMed

    Belkacemi, Yazid; Bourgier, Céline; Kramar, Andrew; Auzac, Guillaume; Dumas, Isabelle; Lacornerie, Thomas; Mége, Jean-Pierre; Mijonnet, Sylvie; Lemonnier, Jerôme; Lartigau, Eric

    2013-02-01

    The standard treatment for breast cancer patients at low risk of recurrence is based on conservative surgery followed by radiation therapy delivered to the whole breast. The accelerated partial breast irradiation (APBI) concept, developed more than 15 years ago, could be an option in selected patients. However, the ideal patient profile for APBI is still not clearly identified. Recent reports from the American Society for Radiation Oncology (ASTRO) and the Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) have suggested selection criteria for "suitable patients" who could receive APBI outside of clinical trials. Currently, there are 6 ongoing phase III trials. All are characterized by a significant heterogeneity regarding inclusion criteria and stratification factors. The French UNICANCER trial (SHARE; ClinicalTrials.gov identifier NCT01247233) will randomize 2,800 patients in 3 arms: APBI (1 week) using 3-dimensional (3D) conformal radiotherapy, standard radiotherapy (6.5 weeks), and hypofractionated radiotherapy (3 weeks). In this article, we review the reported retrospective studies as well as older randomized trials. We will also describe the differences between the 6 ongoing phase III trials and the particularities of the French SHARE trial.

  3. Primary local orbital amyloidosis: biochemical identification of the immunoglobulin light chain kappaIII subtype in a small formalin fixed, paraffin wax embedded tissue sample.

    PubMed

    Kaplan, B; Martin, B M; Cohen, H I; Manaster, J; Kassif, Y; Rehany, U; Livneh, A

    2005-05-01

    Amyloidosis refers to a heterogeneous group of disorders associated with the deposition of chemically distinct amyloid fibril proteins. Precise determination of chemical amyloid type has diagnostic, therapeutic, and prognostic relevance. Although immunohistochemical techniques are used routinely to determine the amyloid type, the results can be negative or inconclusive, so that biochemical characterisation is often required. The development and application of new biochemical microtechniques suitable for examination of extremely small tissue samples is essential for precise identification of the deposited amyloid proteins. To investigate biochemically the amyloid proteins present in a formalin fixed paraffin wax embedded orbital tissue from a patient with localised orbital amyloidosis in whom immunohistochemistry was not helpful in the determination of amyloid type. Extraction of amyloid proteins from fixed tissue and their identification was carried out by a recently developed microtechnique. An extremely small tissue sample was dewaxed and extracted with formic acid. The extracted material was analysed using electrophoresis, western blotting, and amino acid sequencing. Biochemical examination of the extracted proteins showed the presence of immunoglobulin (Ig) derived amyloid proteins, which were composed of the N-terminal fragments of the Ig light chain kappaIII subtype (AL-kappaIII) (16, 8, and 3 kDa). This is the first chemically proved AL case reported in association with primary localised orbital amyloidosis. The biochemical microtechnique used was useful in achieving a precise diagnosis of amyloid disease, in a case where the results of routine immunohistochemical examination of amyloid were inconclusive.

  4. Primary local orbital amyloidosis: biochemical identification of the immunoglobulin light chain κIII subtype in a small formalin fixed, paraffin wax embedded tissue sample

    PubMed Central

    Kaplan, B; Martin, B M; Cohen, H I; Manaster, J; Kassif, Y; Rehany, U; Livneh, A

    2005-01-01

    Background: Amyloidosis refers to a heterogeneous group of disorders associated with the deposition of chemically distinct amyloid fibril proteins. Precise determination of chemical amyloid type has diagnostic, therapeutic, and prognostic relevance. Although immunohistochemical techniques are used routinely to determine the amyloid type, the results can be negative or inconclusive, so that biochemical characterisation is often required. The development and application of new biochemical microtechniques suitable for examination of extremely small tissue samples is essential for precise identification of the deposited amyloid proteins. Aims: To investigate biochemically the amyloid proteins present in a formalin fixed paraffin wax embedded orbital tissue from a patient with localised orbital amyloidosis in whom immunohistochemistry was not helpful in the determination of amyloid type. Methods: Extraction of amyloid proteins from fixed tissue and their identification was carried out by a recently developed microtechnique. An extremely small tissue sample was dewaxed and extracted with formic acid. The extracted material was analysed using electrophoresis, western blotting, and amino acid sequencing. Results: Biochemical examination of the extracted proteins showed the presence of immunoglobulin (Ig) derived amyloid proteins, which were composed of the N-terminal fragments of the Ig light chain κIII subtype (AL-κIII) (16, 8, and 3 kDa). Conclusions: This is the first chemically proved AL case reported in association with primary localised orbital amyloidosis. The biochemical microtechnique used was useful in achieving a precise diagnosis of amyloid disease, in a case where the results of routine immunohistochemical examination of amyloid were inconclusive. PMID:15858128

  5. A Geobacter sulfurreducens strain expressing pseudomonas aeruginosa type IV pili localizes OmcS on pili but is deficient in Fe(III) oxide reduction and current production.

    PubMed

    Liu, Xing; Tremblay, Pier-Luc; Malvankar, Nikhil S; Nevin, Kelly P; Lovley, Derek R; Vargas, Madeline

    2014-02-01

    The conductive pili of Geobacter species play an important role in electron transfer to Fe(III) oxides, in long-range electron transport through current-producing biofilms, and in direct interspecies electron transfer. Although multiple lines of evidence have indicated that the pili of Geobacter sulfurreducens have a metal-like conductivity, independent of the presence of c-type cytochromes, this claim is still controversial. In order to further investigate this phenomenon, a strain of G. sulfurreducens, designated strain PA, was constructed in which the gene for the native PilA, the structural pilin protein, was replaced with the PilA gene of Pseudomonas aeruginosa PAO1. Strain PA expressed and properly assembled P. aeruginosa PilA subunits into pili and exhibited a profile of outer surface c-type cytochromes similar to that of a control strain expressing the G. sulfurreducens PilA. Surprisingly, the strain PA pili were decorated with the c-type cytochrome OmcS in a manner similar to the control strain. However, the strain PA pili were 14-fold less conductive than the pili of the control strain, and strain PA was severely impaired in Fe(III) oxide reduction and current production. These results demonstrate that the presence of OmcS on pili is not sufficient to confer conductivity to pili and suggest that there are unique structural features of the G. sulfurreducens PilA that are necessary for conductivity.

  6. A quantitative method to evaluate corrosion products in tissues.

    PubMed

    Cabrini, R L; Olmedo, D G; Guglielmotti, M B

    2003-01-01

    The use of odontological or orthopedic metal implants requires the availability of techniques to estimate tissue response to the corrosion processes. In previous experimental studies we showed the deposition of corrosion products not only locally (Olmedo et al., Implant Dent 2003; 12: 75-80) but also systemically (Olmedo et al., J Mater Sci: Mater in Medic 2002; 13: 793-796) in organs such as liver, spleen and lung. The aim of the present study was to propose a method to quantitatively assess the tissue deposits of the corrosion products of the materials used to manufacture implants. The samples (liver and lung) were embedded in paraffin, and the histological sections were submitted to thickness standardization. The quantitative evaluation of the deposits was performed in an MPM-800 (Carl Zeiss)* microscope. The light microscopy images were digitalized and then analyzed employing the DNA-IBAS-Kontron software that allows for the identification and evaluation of cells loaded with corrosion products (objective 20x). The following end-points were assessed: total field area, number of deposits of corrosion products, partial and total area of the deposits, and the ratio between volume of the deposits and tissue volume. The method proposed serves to quantitatively evaluate, at light microscopy level, the deposition of corrosion products in tissues.

  7. Role of microbial induced corrosion in subsea water pipeline failure

    SciTech Connect

    Samant, A.K.; Singh, S.K.

    1998-12-31

    Premature failure of subsea water injection pipelines due to rupture was observed in Indian offshore facilities. In this connection various contributing factors like metallurgy of pipeline, operating conditions and corrosion related parameters have been examined. Material defects that can lead to premature failure of pipelines like microstructural anomalies, variation in hardness and elemental composition and tensile strength etc. have been found within the specified limits of material specification. Analysis of various operating parameters and water quality data indicated failure due to microbial induced internal corrosion. Due to low flow velocities, suspended insoluble corrosion products, bacteria and other microbes, present in the water, accumulated inside the pipeline surface mostly in low areas. Deposit provided hiding place for bacteria and shielded them from effective treatment by bactericide. Deposits also resulted in the formation of oxygen concentration cells resulting in localized corrosion. Non-pigging of pipe lines, even after long shut down, also resulted in accumulation of deposits. During this period, microbial activities dominated resulting in the formation of acidic metabolizes which ultimately led to internal corrosion. In this paper, all above aspects have been examined with special reference to the role of microbiologically induced corrosion for failure of subsea water injection pipe lines.

  8. Stress corrosion cracking tests using double-cantilever-beam specimens

    SciTech Connect

    Roy, A

    1996-10-25

    Although a wide variety of degradation modes can occur in aqueous environments for corrosion-resistant metallic materials, localized corrosion such as pitting corrosion, crevice corrosion, SCC, and hydrogen embrinlement (HE) is considered to be the primary mode. The evaluation of the susceptibility of candidate corrosion-resistant container materials to pitting and crevice corrosion is well underway using electrochemical polarization techniques described in the Activity Plan E-20-43144. The proposed activity (E-20-56) is aimed at evaluating the SCC behavior of these materials in susceptible environments using the linearelastic-fracture-mechanics (LEFM) concept. The mechanical driving force for crack growth, or the stress distribution at the crack tip is quantified by the stress intensity factor, K, for the specific crack and loading geometry. The critical stress intensity factor for SCC, KISCC for candidate materials will be evaluated in environments of interest, and their comparisons will be made to select the waste package inner container material having an optimum SCC resistance.

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. Corrosion and stress corrosion cracking in supercritical water

    NASA Astrophysics Data System (ADS)

    Was, G. S.; Ampornrat, P.; Gupta, G.; Teysseyre, S.; West, E. A.; Allen, T. R.; Sridharan, K.; Tan, L.; Chen, Y.; Ren, X.; Pister, C.

    2007-09-01

    Supercritical water (SCW) has attracted increasing attention since SCW boiler power plants were implemented to increase the efficiency of fossil-based power plants. The SCW reactor (SCWR) design has been selected as one of the Generation IV reactor concepts because of its higher thermal efficiency and plant simplification as compared to current light water reactors (LWRs). Reactor operating conditions call for a core coolant temperature between 280 °C and 620 °C at a pressure of 25 MPa and maximum expected neutron damage levels to any replaceable or permanent core component of 15 dpa (thermal reactor design) and 100 dpa (fast reactor design). Irradiation-induced changes in microstructure (swelling, radiation-induced segregation (RIS), hardening, phase stability) and mechanical properties (strength, thermal and irradiation-induced creep, fatigue) are also major concerns. Throughout the core, corrosion, stress corrosion cracking, and the effect of irradiation on these degradation modes are critical issues. This paper reviews the current understanding of the response of candidate materials for SCWR systems, focusing on the corrosion and stress corrosion cracking response, and highlights the design trade-offs associated with certain alloy systems. Ferritic-martensitic steels generally have the best resistance to stress corrosion cracking, but suffer from the worst oxidation. Austenitic stainless steels and Ni-base alloys have better oxidation resistance but are more susceptible to stress corrosion cracking. The promise of grain boundary engineering and surface modification in addressing corrosion and stress corrosion cracking performance is discussed.

  14. 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

    2015-11-30

    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.

  15. Identification of key factors in Accelerated Low Water Corrosion through experimental simulation of tidal conditions: influence of stimulated indigenous microbiota.

    PubMed

    Marty, Florence; Gueuné, Hervé; Malard, Emilie; Sánchez-Amaya, José M; Sjögren, Lena; Abbas, Ben; Quillet, Laurent; van Loosdrecht, Mark C M; Muyzer, Gerard

    2014-01-01

    Biotic and abiotic factors favoring Accelerated Low Water Corrosion (ALWC) on harbor steel structures remain unclear warranting their study under controlled experimental tidal conditions. Initial stimulation of marine microbial consortia by a pulse of organic matter resulted in localized corrosion and the highest corrosion rates (up to 12-times higher than non-stimulated conditions) in the low water zone, persisting after nine months exposure to natural seawater. Correlations between corrosion severity and the abundance and composition of metabolically active sulfate-reducing bacteria (SRB) indicated the importance and persistence of specific bacterial populations in accelerated corrosion. One phylotype related to the electrogenic SRB Desulfopila corrodens appeared as the major causative agent of the accelerated corrosion. The similarity of bacterial populations related to sulfur and iron cycles, mineral and tuberculation with those identified in ALWC support the relevance of experimental simulation of tidal conditions in the management of steel corrosion exposed to harbor environments.

  16. Microbial fouling and corrosion of carbon steel in deep anoxic alkaline groundwater.

    PubMed

    Rajala, Pauliina; Bomberg, Malin; Vepsäläinen, Mikko; Carpén, Leena

    2017-02-01

    Understanding the corrosion of carbon steel materials of low and intermediate level radioactive waste under repository conditions is crucial to ensure the safe storage of radioactive contaminated materials. The waste will be in contact with the concrete of repository silos and storage containers, and eventually with groundwater. In this study, the corrosion of carbon steel under repository conditions as well as the microbial community forming biofilm on the carbon steel samples, consisting of bacteria, archaea, and fungi, was studied over a period of three years in a groundwater environment with and without inserted concrete. The number of biofilm forming bacteria and archaea was 1,000-fold lower, with corrosion rates 620-times lower in the presence of concrete compared to the natural groundwater environment. However, localized corrosion was detected in the concrete-groundwater environment indicating the presence of local microenvironments where the conditions for pitting corrosion were favorable.

  17. Direct laser-assisted synthesis of localized gold nanoparticles from both Au (III) and Au (I) precursors within a silica monolith

    NASA Astrophysics Data System (ADS)

    Tonelli, M.; Turrell, S.; Cristini, O.; El Hamzaoui, H.; Capoen, B.; Bouazaoui, M.; Kinowski, C.; Gazzano, M.; Cassani, M. C.

    2012-04-01

    This work presents a solvent-free and laser-assisted growth of gold nanoparticles (Au-NPs) within silica monoliths using both Au(III) and Au(I) precursors. The novelty of the synthesis method is that Au-NPs of about 20 nm in diameter were obtained well dispersed in the matrix with no need of either reducing or capping agents. Moreover, the laser-assisted synthetic procedure here described made it possible to obtain reproducible 2D and 3D patterns of Au-NPs. For this purpose, suitable Au(I) and Au(III) precursors, soluble in dichloromethane, were easily prepared following a well-known procedure. The mesoporous silica matrix was first loaded with the precursors via a simple impregnation and then irradiated using either a continuous laser (λ= 266 or 532 nm) or a pulsed laser (λ=800 nm; pulse: 120 fs; repetition rate: 1KHz). In all cases, a photothermal gold reduction was observed. The Au-NPs have been characterized using UV-vis absorption spectroscopy, x-ray diffraction and Transmission Electron Microscopy. Finally it is shown that the excess gold precursors can be removed after the Au-NP synthesis by a simple washing of the monolith with a few immersions in the pure solvent. The stability of the Au-NPs was further tested by a series of heat-treatments up to 500°C, showing that the silica monolith acts as an effective support to prevent the agglomeration of the nanoparticles.

  18. 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

  19. 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

  20. Corrosion behavior of a welded stainless-steel orthopedic implant.

    PubMed

    Reclaru, L; Lerf, R; Eschler, P Y; Meyer, J M

    2001-02-01

    The corrosion behavior of combinations of materials used in an orthopedic implant: the spherical part (forged or forged and annealed) constituting the head, the weld (tungsten inert gas (TIG) or electron beam (EB) techniques), and the cylindrical part (annealed) constituting the shaft of a femoral prosthesis - has been investigated. Open-circuit potentials, potentiodynamic curves, Tafel slope, mixed potential theory and susceptibility to intergranular attack are electrochemical and chemical procedures selected for this work. Electrochemical measurements using a microelectrode have been made in the following zones: spherical part, cylindrical part, weld, and weld/sphere, and weld/shaft interfaces. To detect intergranular attack, the Strauss test has been used. At the interfaces, corrosion currents, measured (Icorr) and predicted (Icouple) are low, in the order of the pico- to nanoampere. The electrochemical behavior of the electron beam (EB) weld is better than that of the tungsten inert gas (TIG). Welds at interfaces can behave either anodically or cathodically. It is better if welds, which are sensitive parts of the femoral prosthesis, behave cathodically. In this way, the risk of starting localized corrosion (pitting, crevice or intergranular corrosion) from a galvanic couple, remains low. From this point of view, the sample with the EB weld offers the best behavior. All the other samples containing a TIG type of weld exhibit a less favorable behavior. The mechanical treatments (forged, and forged and annealed) of the steel sphere did not show any difference in the corrosion behavior. No intergranular corrosion has been observed at the weld/steel interface for unsensitized samples. With sensitized samples, however, a TIG sample has exhibited some localized intergranular corrosion at a distance of 500 microm along the weld/stainless steel (sphere) interface.

  1. Global Positioning System III (GPS III)

    DTIC Science & Technology

    2013-12-01

    Global Positioning System III ( GPS III) As of FY 2015 President’s Budget...00-00-2013 to 00-00-2013 4. TITLE AND SUBTITLE Global Positioning System III ( GPS III) 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...Responsible Office References Program Name Global Positioning System III ( GPS III) DoD Component Air Force

  2. Dissemination and Use of Materials to Facilitate Locally Directed Evaluation of Community College Agricultural Occupations Programs. Phase III, July 1, 1976 through June 30, 1980.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Dept. of Vocational and Technical Education.

    This evaluation guide is designed to assist local community college instructors, administrators, and other persons in the evaluation of their agricultural occupations program. The first of three sections provides an introduction and discusses (1) how standards benefit students, colleges, and the community; (2) how to prepare for a review of the…

  3. NolX of Sinorhizobium fredii USDA257, a Type III-Secreted Protein Involved in Host Range Determination, Is Localized in the Infection Threads of Cowpea (Vigna unguiculata [L.] Walp) and Soybean (Glycine max [L.] Merr.) Nodules

    PubMed Central

    Krishnan, Hari B.

    2002-01-01

    Sinorhizobium fredii USDA257 forms nitrogen-fixing nodules on soybean (Glycine max [L.] Merr.) in a cultivar-specific manner. This strain forms nodules on primitive soybean cultivars but fails to nodulate agronomically improved North American cultivars. Soybean cultivar specificity is regulated by the nolXWBTUV locus, which encodes part of a type III secretion system (TTSS). NolX, a soybean cultivar specificity protein, is secreted by TTSS and shows homology to HrpF of the plant pathogen Xanthomonas campestris pv. vesicatoria. It is not known whether NolX functions at the bacterium-plant interface or acts inside the host cell. Antibodies raised against S. fredii USDA257 NolX were used in immunocytochemical studies to investigate the subcellular localization of this protein. Immunostaining of paraffin-embedded sections of developing soybean and cowpea (Vigna unguiculata [L.] Walp) nodules revealed localization of NolX in the infection threads. Protein A-gold immunocytochemical localization studies utilizing affinity-purified NolX antibodies revealed specific deposition of gold particles in the fibrillar material inside infection threads. Similar immunogold localization studies failed to detect NolX in thin sections of mature soybean and cowpea nodules. The results from this study indicate that NolX is expressed in planta only during the early stages of nodule development. PMID:11790754

  4. Agricultural Polymers as Corrosion Inhibitors

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Microbiologically Influenced Corrosion: an Update

    DTIC Science & Technology

    2014-01-01

    microbial/metal interactions. Microbiologically influenced corrosion, Sulphate reducing bacteria , Electrogenic bacteria , Electron acceptors, Microbial...Keywords: Microbiologically influenced corrosion, Sulphate reducing bacteria , Electrogenic bacteria , Electron acceptors, Microbial fuel cell Introduction...causative microorganisms are from all three main branches of evolutionary descent, i.e., bacteria , archaea (methanogens), and eukaryota (fungi

  6. 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.

  7. 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.

  8. 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...

  9. 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...

  10. Long-term corrosion studies

    SciTech Connect

    Gdowski, G.

    1998-05-29

    The scope of this activity is to assess the long-term corrosion properties of metallic materials under consideration for fabricating waste package containers. Three classes of metals are to be assessed: corrosion resistant, intermediate corrosion resistant, and corrosion allowance. Corrosion properties to be evaluated are general, pitting and crevice corrosion, stress-corrosion cracking, and galvanic corrosion. The performance of these materials will be investigated under conditions that are considered relevant to the potential emplacement site. Testing in four aqueous solutions, and vapor phases above them, and at two temperatures are planned for this activity. (The environmental conditions, test metals, and matrix are described in detail in Section 3.0.) The purpose and objective of this activity is to obtain the kinetic and mechanistic information on degradation of metallic alloys currently being considered for waste package containers. This information will be used to provide assistance to (1) waste package design (metal barrier selection) (E-20-90 to E-20-92), (2) waste package performance assessment activities (SIP-PA-2), (3) model development (E-20-75 to E-20-89). and (4) repository license application.

  11. Corrosion-Resistant Ball Bearings

    NASA Technical Reports Server (NTRS)

    Zdankiewicz, E. M.; Linaburg, E. L.; Lytle, L. J.

    1990-01-01

    Self-lubricating bearing system withstands highly corrosive environment of wastewater-recycling unit. New bearings contain cobalt-based-alloy balls and races, graphite/polyimide polymer ball cages, and single integral polytetrafluoroethylene seals on wet sides. Materials and design prevent corrosion by acids and provide lubrication.

  12. 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.

  13. 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.

  14. Avionics Corrosion Control Study

    DTIC Science & Technology

    1974-01-01

    contact with-caustic soda , washing soda , or lime. One of the most har:iiful materials when In contact with aluminum is mercury or any of its salts. Mercury...used with weaker acids such as vinegar . lemon juice, etc. In general, aluminum and its alloys exhibit a wide range of corrosive attack, varying front...SM-43) -(TT-1-7435) 6850-X.13-1544 San-Del #2 Technical Cleaner Baking SoaM. P. Odell Co. Armor (’ 1348) $950-29)2-9611 1169-A Insulating Lacquer Base

  15. 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.

  16. 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.

  17. Welding III.

    ERIC Educational Resources Information Center

    Allegheny County Community Coll., Pittsburgh, PA.

    Instructional objectives and performance requirements are outlined in this course guide for Welding III, an advanced course in arc welding offered at the Community College of Allegheny County to provide students with the proficiency necessary for industrial certification. The course objectives, which are outlined first, specify that students will…

  18. Welding III.

    ERIC Educational Resources Information Center

    Allegheny County Community Coll., Pittsburgh, PA.

    Instructional objectives and performance requirements are outlined in this course guide for Welding III, an advanced course in arc welding offered at the Community College of Allegheny County to provide students with the proficiency necessary for industrial certification. The course objectives, which are outlined first, specify that students will…

  19. Simulation of Corrosion Using Molecular Automation

    NASA Astrophysics Data System (ADS)

    Zhang, Yingrui

    There exist many systems in Nature which present overall behavior of great complexity. Yet research in chemistry and physics has shown that the fundamental components of many systems are quite simple. The observed great complexity has its origin in the simple interactions between fundamental components. For example, corrosion of metals in aqueous environments involves elemental particles such as metal atoms, water molecules, and ions in the solution. Each elemental particle interacts with neighboring species according to the rules of Nature. When large amounts of these individual reactions act together, diverse corrosion phenomena of great complexity are generated. Conceptually, if a simulation correctly implements the interactions between species, system behaviors should spontaneously arise from the simulation. The molecular automation developed in this work takes the approach of Nature to model the local interactions between individual particles, allowing corrosion phenomena to emerge spontaneously as outcomes of the simulation. Atoms, molecules, and ions are simplified to be particles of no size or weight. Each particle interacts with neighboring species based on the local information regarding its immediate neighbors. Species interactions are represented as thermally activated events which occur probabilistically, mimicking the thermal activation mechanism so prevalent in Nature. A set of rules that imitates the process of Nature is developed to govern the reactions between species. Since corrosion is an interfacial phenomena which considers both the solution and the metal phase, this work addresses the applications of molecular automation to the physical chemistry in solutions, the distribution of electrons in metals, and finally the structural features of the electrical double layer. Both two-dimensional and three-dimensional models have been developed. Parallel computation using Nvidia(TM)'s graphics processing unit (GPU) and compute unified device

  20. 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...