WorldWideScience

Sample records for biologically mediated corrosion

  1. Relationship between corrosion and the biological sulfur cycle: A review

    Energy Technology Data Exchange (ETDEWEB)

    Little, B.J.; Ray, R.I.; Pope, R.K.

    2000-04-01

    Sulfur and sulfur compounds can produce pitting, crevice corrosion, dealloying, stress corrosion cracking, and stress-oriented hydrogen-induced cracking of susceptible metals and alloys. Even though the metabolic by-products of the biological sulfur cycle are extremely corrosive, there are no correlations between numbers and types of sulfur-related organisms and the probability or rate of corrosion, Determination of specific mechanisms for corrosion caused by microbiologically mediated oxidation and reduction of sulfur and sulfur compounds is complicated by the variety of potential metabolic-energy sources and by-products; the coexistence of reduced and oxidized sulfur species; competing reactions with inorganic and organic compounds; and the versatility and adaptability of microorganisms in biofilms. The microbial ecology of sulfur-rich environments is poorly understood because of the association of aerobes and anaerobes and the mutualism or succession of heterotrophs to autotrophs. The physical scale over which the sulfur cycle influences corrosion varies with the environment. The complete sulfur cycle of oxidation and reduction reactions can take place in macroenvironments, including sewers and polluted harbors, or within the microenvironment of biofilms. In this review, reactions of sulfur and sulfur compounds resulting in corrosion were discussed in the context of environmental processes important to corrosion.

  2. A strain-mediated corrosion model for bioabsorbable metallic stents.

    Science.gov (United States)

    Galvin, E; O'Brien, D; Cummins, C; Mac Donald, B J; Lally, C

    2017-06-01

    This paper presents a strain-mediated phenomenological corrosion model, based on the discrete finite element modelling method which was developed for use with the ANSYS Implicit finite element code. The corrosion model was calibrated from experimental data and used to simulate the corrosion performance of a WE43 magnesium alloy stent. The model was found to be capable of predicting the experimentally observed plastic strain-mediated mass loss profile. The non-linear plastic strain model, extrapolated from the experimental data, was also found to adequately capture the corrosion-induced reduction in the radial stiffness of the stent over time. The model developed will help direct future design efforts towards the minimisation of plastic strain during device manufacture, deployment and in-service, in order to reduce corrosion rates and prolong the mechanical integrity of magnesium devices. The need for corrosion models that explore the interaction of strain with corrosion damage has been recognised as one of the current challenges in degradable material modelling (Gastaldi et al., 2011). A finite element based plastic strain-mediated phenomenological corrosion model was developed in this work and was calibrated based on the results of the corrosion experiments. It was found to be capable of predicting the experimentally observed plastic strain-mediated mass loss profile and the corrosion-induced reduction in the radial stiffness of the stent over time. To the author's knowledge, the results presented here represent the first experimental calibration of a plastic strain-mediated corrosion model of a corroding magnesium stent. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  3. Defects Mediated Corrosion in Graphene Coating Layer.

    Science.gov (United States)

    Lei, Jincheng; Hu, Yaowu; Liu, Zishun; Cheng, Gary J; Zhao, Kejie

    2017-04-05

    Mixed results were reported on the anticorrosion of graphene-coated metal surfaces-while graphene serves as an effective short-term barrier against corrosion and oxidation due to its low permeability to gases, the galvanic cell between graphene and the metal substrate facilitates extensive corrosion in the long run. Defects in the graphene layer provide pathways for the permeation of oxidizing species. We study the role of defects in graphene in the anticorrosion using first-principles theoretical modeling. Experiments in the highly reactive environment indicate that the oxidized products primarily distribute along the grain boundaries of graphene. We analyze the thermodynamics of the absorption of S and O on the grain boundaries of graphene on the basis of density functional theory. The insertion of S and O at the vacancy sites is energetically favorable. The interstitial impurities facilitate structural transformation of graphene and significantly decrease the mechanical strength of the graphene layer. Furthermore, the presence of the interstitial S and O reduces the chemical stability of graphene by enhancing the formation of vacancies and promoting dispersive growth of corrosive reactants along the grain boundaries.

  4. Corrosion

    Science.gov (United States)

    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)

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

    Science.gov (United States)

    Walsh, Daniel W.

    1991-01-01

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

  6. The Relationship Between Corrosion and the Biological Sulfur Cycle

    National Research Council Canada - National Science Library

    Little, Brenda

    2000-01-01

    .... Sulfur and sulfur compounds, including sulfides, bisulfides, hydrogen sulfide (H2S), thiosulfates, polythionates and sulfuric acid, may be trapped or bound up in biofilms causing direct corrosion of materials...

  7. Characterization of the corrosion resistance of several alloys to dilute biologically active solutions

    Science.gov (United States)

    Walsh, Daniel W.

    1990-01-01

    Sulfate reducing bacteria and acid producing bacteria/fungi detected in hygiene waters increased the corrosion rate in aluminum alloy. Biologically active media enhanced the formation of pits on metal coupons. Direct observation of gas evolved at the corrosion sample, coupled with scanning electron microscopy (SEM) and energy dispersive x-ray analysis of the corrosion products indicates that the corrosion rate is increased because the presence of bacteria favor the reduction of hydrogen as the cathodic reaction through the reaction of oxygen and water. SEM verifies the presence of microbes in a biofilm on the surface of corroding samples. The bacterial consortia are associated with anodic sites on the metal surface, aggressive pitting occurs adjacent to biofilms. Many pits are associated with triple points and inclusions in the aluminum alloy microstructure. Similar bacterial colonization was found on the stainless steel samples. Fourier transform Infrared Spectroscopy confirmed the presence of carbonyl groups in pitted areas of samples exposed to biologically active waters.

  8. Biologically mediated dissolution of volcanic glass in seawater

    NARCIS (Netherlands)

    Staudigel, H.; Chastain, R.A.; Yayanos, A.; Davies, G.R.; Verdurmen, E.; Schiffman, P.; Bourcier, R.; de Baar, H.

    1998-01-01

    We studied the effects of biological mediation on the dissolution of basaltic glass in seawater. Experiments with typical seawater microbial populations were contrasted with a sterile control, and reactions were monitored chemically and isotopically. Biologically mediated experiments produce twice

  9. The corrosion inhibition of iron and aluminum by various naturally occurring biological molecules

    Energy Technology Data Exchange (ETDEWEB)

    McCafferty, E.; Hansen, D.C. [Naval Research Lab., Washington, DC (United States)

    1995-12-31

    Biological polymers that exhibit a strong affinity for metal surfaces are increasingly becoming the focus of research toward the development of environmentally friendly corrosion inhibitors. This paper deals with the use of various naturally occurring organic molecules as corrosion inhibitors for iron or aluminum. Among the organic molecules considered are catecholate and hydroxamate siderophores isolated from bacteria, the adhesive protein from the blue mussel Mytilus edulis L, and caffeic acid and chlorogenic acid. FTIR analysis, anodic polarization curves, and AC impedance measurements were used to determine the adsorption and effectiveness of the various organic molecules as corrosion inhibitors. Parabactin, a catecholate siderophore, was effective in inhibiting both the corrosion of iron in hydrochloric acid and the pitting of aluminum in 0.1 M sodium chloride. The adhesive protein from the blue mussel was also effective in inhibiting the pitting of aluminum.

  10. Corrosion of magnesium and magnesium–calcium alloy in biologically-simulated environment

    Directory of Open Access Journals (Sweden)

    Richard Harrison

    2014-10-01

    Full Text Available A study of biocompatibility and corrosion of both metallic magnesium (Mg and a magnesium alloy containing 1% calcium (Mg–Ca were investigated in in vitro culture conditions with and without the presence of bone marrow derived human mesenchymal stem cells (hMSCs. Chemical analysis of the degraded samples was performed using XRD and FEGSEM. The results from the XRD analysis strongly suggested that crystalline phase of magnesium carbonate was present on the surface of both the Mg and Mg–Ca samples. Flame absorption spectrometry was used to analyse the release of magnesium and calcium ions into the cell culture medium. Magnesium concentration was kept consistently at a level ranging from 40 to 80 mM for both Mg and Mg–Ca samples. No cell growth was observed when in direct contact with the metals apart from a few cells observed at the bottom of culture plate containing Mg–Ca alloy. In general, in vitro study of corrosion of Mg–Ca in a biologically-simulated environment using cell culture medium with the presence of hMSCs demonstrated close resemblances to in vivo corrosion. Although in vitro corrosion of Mg–Ca revealed slow corrosion rate and no immediate cytotoxicity effects to hMSCs, its corrosion rate was still too high to achieve normal stem cell growth when cells and alloys were cultured in vitro in direct contact.

  11. [Biological investigation of kinin-mediated angioedema].

    Science.gov (United States)

    Defendi, F; Charignon, D; Ghannam, A; Ponard, D; Drouet, C

    2015-03-01

    Kinin-mediated angioedema results from accumulation of kinins, vasoactive and vasopermeant peptides, on the vascular endothelium. The disease is characterized by sudden episodes of swelling in the subcutaneous and submucosal tissues; the edema may occur spontaneously or it may be precipitated by triggering factors such as physical or emotional stress, or certain medicines. The characterization of kinin formation and catabolism systems helps improve knowledge of the aetiopathogenic mechanisms involved and provides the basis for classification of kinin-mediated angioedema conditions; thus, we may distinguish between angioedema with C1 inhibitor deficiency, whether inherited or acquired, and angioedema with normal C1 inhibitor activity, associated with increased kinin-forming activity or deficiency in kinin catabolism enzymes. In support of the clinical diagnosis, the physician may request laboratory investigation for a functional and molecular definition of the disease. Laboratory diagnosis is based on the characterization of: (1) kinin production control by C1 inhibitor investigation (function, antigen levels and circulating species); (2) kinin production (kininogenase activity, kininogen cleavage species); and (3) kinin catabolism enzymes (aminopeptidase P, carboxypeptidase N, angiotensin-I converting enzyme and dipeptidyl peptidase IV). An abnormal biological phenotype is supported by examination of susceptibility genes (SERPING1, F12 and XPNPEP2) and mutation segregation in the families. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Ni-Cr based dental alloys; Ni release, corrosion and biological evaluation.

    Science.gov (United States)

    Reclaru, L; Unger, R E; Kirkpatrick, C J; Susz, C; Eschler, P-Y; Zuercher, M-H; Antoniac, I; Lüthy, H

    2012-08-01

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10-15% for female adults and 1-3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni-Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni-Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. STAT6: its role in interleukin 4-mediated biological functions.

    Science.gov (United States)

    Takeda, K; Kishimoto, T; Akira, S

    1997-05-01

    Interleukin (IL) 4 is known to be a cytokine which plays a central role in the regulation of immune response. Studies on cytokine signal transduction have clarified the mechanism by which IL4 exerts its functions. Two cytoplasmic proteins, signal transducer and activator of transcription (STAT) 6 and IL4-induced phosphotyrosine substrate/insulin receptor substrate 2 (4PS/IRS2), are activated in IL4 signal transduction. Recent studies from STAT6-deficient mice have revealed the essential role of STAT6 in IL4-mediated biological actions. In addition, STAT6 has also been demonstrated to be important for the functions mediated by IL13, which is related to IL4. IL4 and IL13 have been shown to induce the production of IgE, which is a major mediator in an allergic response. These findings indicate that STAT6 activation is involved in IL4- and IL13-mediated disorders such as allergy.

  14. Ni-Cr based dental alloys; Ni release, corrosion and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Reclaru, L., E-mail: lucien.reclaru@pxgroup.com [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Unger, R.E.; Kirkpatrick, C.J. [Institute for Pathology, REPAIR Lab, University Medical Center, Johannes Gutenberg University Mainz, Langenbeckstr.1, D-55101 Mainz (Germany); Susz, C.; Eschler, P.-Y.; Zuercher, M.-H. [PX Holding S.A., Dep R and D Corrosion and Biocompatibility Group, Bd. des Eplatures 42, CH-2304 La Chaux-de-Fonds (Switzerland); Antoniac, I. [Materials Science and Engineering Faculty, Politehnica of Bucharest, 060042 Bucharest (Romania); Luethy, H. [Institute of Dental Materials Science and Technology, University of Basel, Hebelstrasse 3, CH-4056 Basel (Switzerland)

    2012-08-01

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10-15% for female adults and 1-3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni-Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni-Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: Black-Right-Pointing-Pointer Nickel released was higher than the limits imposed in EU in contact with the skin. Black-Right-Pointing-Pointer No direct relationship between the

  15. Ni–Cr based dental alloys; Ni release, corrosion and biological evaluation

    International Nuclear Information System (INIS)

    Reclaru, L.; Unger, R.E.; Kirkpatrick, C.J.; Susz, C.; Eschler, P.-Y.; Zuercher, M.-H.; Antoniac, I.; Lüthy, H.

    2012-01-01

    In the last years the dental alloy market has undergone dramatic changes for reasons of economy and biocompatibility. Nickel based alloys have become widely used substitute for the much more expensive precious metal alloys. In Europe the prevalence of nickel allergy is 10–15% for female adults and 1–3% for male adults. Despite the restrictions imposed by the EU for the protection of the general population in contact dermatitis, the use of Ni–Cr dental alloys is on the increase. Some questions have to be faced regarding the safety risk of nickel contained in dental alloys. We have collected based on many EU markets, 8 Ni–Cr dental alloys. Microstructure characterization, corrosion resistance (generalized, crevice and pitting) in saliva and the quantities of cations released in particular nickel and CrVI have been evaluated. We have applied non parametric classification tests (Kendall rank correlation) for all chemical results. Also cytotoxicity tests and an evaluation specific to TNF-alpha have been conducted. According to the obtained results, it was found that their behavior to corrosion was weak but that nickel release was high. The quantities of nickel released are higher than the limits imposed in the EU concerning contact with the skin or piercing. Surprisingly the biological tests did not show any cytotoxic effect on Hela and L929 cells or any change in TNF-alpha expression in monocytic cells. The alloys did not show any proinflammatory response in endothelial cells as demonstrated by the absence of ICAM-1 induction. We note therefore that there is really no direct relationship between the in vitro biological evaluation tests and the physico-chemical characterization of these dental alloys. Clinical and epidemiological studies are required to clarify these aspects. - Highlights: ► Nickel released was higher than the limits imposed in EU in contact with the skin. ► No direct relationship between the biological evaluation and chemical degradation.

  16. Corrosion resistance and biological activity of TiO2implant coatings produced in oxygen-rich environments.

    Science.gov (United States)

    Zhang, Rui; Wan, Yi; Ai, Xing; Liu, Zhanqiang; Zhang, Dong

    2017-01-01

    The physical and chemical properties of bio-titanium alloy implant surfaces play an important role in their corrosion resistance and biological activity. New turning and turning-rolling processes are presented, employing an oxygen-rich environment in order to obtain titanium dioxide layers that can both protect implants from corrosion and also promote cell adhesion. The surface topographies, surface roughnesses and chemical compositions of the sample surfaces were obtained using scanning electron microscopy, a white light interferometer, and the Auger electron spectroscopy, respectively. The corrosion resistance of the samples in a simulated body fluid was determined using electrochemical testing. Biological activity on the samples was also analyzed, using a vitro cell culture system. The results show that compared with titanium oxide layers formed using a turning process in air, the thickness of the titanium oxide layers formed using turning and turning-rolling processes in an oxygen-rich environment increased by 4.6 and 7.3 times, respectively. Using an oxygen-rich atmosphere in the rolling process greatly improves the corrosion resistance of the resulting samples in a simulated body fluid. On samples produced using the turning-rolling process, cells spread quickly and exhibited the best adhesion characteristics.

  17. Corrosion inhibition of iota-carrageenan natural polymer on aluminum in presence of zwitterion mediator in HCl media

    International Nuclear Information System (INIS)

    Fares, Mohammad M.; Maayta, A.K.; Al-Mustafa, Jamil A.

    2012-01-01

    Highlights: ► Inhibition of Al by ι-carrageenan in the presence of zwitterion mediator was investigated. ► Considerable improvement in inhibition efficiency observed in the presence of zwitterion mediator. ► Coherent physical adsorption layer was evidenced by kinetic and thermodynamic parameters. ► Small but consistent fractured island layers observed after acid exposure as revealed by SEM images. - Abstract: ι-Carrageenan a natural polymer has been used as corrosion inhibitor of aluminum in presence of pefloxacin mesylate, acting as zwitterionic mediator, in acidic medium. Considerable improvement in inhibition efficiency occurred in the presence of the mediator. Activation energy of corrosion and other thermodynamic parameters such as standard free energy, standard enthalpy, and standard entropy of the adsorption process revealed better and well-ordered physical adsorption layers in presence of pefloxacin. Adsorption isotherms in absence or presence of pefloxacin mediator appropriately fit in the Langmuir isotherms. The scanning electron microscope (SEM) images demonstrated smooth, glossy, and relatively coherent adsorption layers of the inhibitor on the metal surface in aqueous solution. After the exposure to 2.0 M HCl for 2 h, a smaller but consistent regular shaped fractured layer is obtained.

  18. Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure.

    Science.gov (United States)

    Besleaga, Cristina; Dumitru, Viorel; Trinca, Liliana Marinela; Popa, Adrian-Claudiu; Negrila, Constantin-Catalin; Kołodziejczyk, Łukasz; Luculescu, Catalin-Romeo; Ionescu, Gabriela-Cristina; Ripeanu, Razvan-George; Vladescu, Alina; Stan, George E

    2017-11-17

    Aluminum Nitride (AlN) has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors). AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for its intrinsic piezoelectricity, its surface morphology and mechanical performance (elastic modulus, hardness, wear, scratch and tensile resistance to delamination, adherence to the substrate), corrosion resistance and cytocompatibility are also essential features for high performance sustainable biosensor devices. However, information about AlN suitability for such applications is rather scarce or at best scattered and incomplete. Here, we aim to deliver a comprehensive evaluation of the morpho-structural, compositional, mechanical, electrochemical and biological properties of reactive radio-frequency magnetron sputtered AlN nanostructured thin films with various degrees of c -axis texturing, deposited at a low temperature (~50 °C) on Si (100) substrates. The inter-conditionality elicited between the base pressure level attained in the reactor chamber and crystalline quality of AlN films is highlighted. The potential suitability of nanostructured AlN (in form of thin films) for the realization of various type of sensors (with emphasis on bio-sensors) is thoroughly probed, thus unveiling its advantages and limitations, as well as suggesting paths to safely exploit the remarkable prospects of this type of materials.

  19. Mechanical, Corrosion and Biological Properties of Room-Temperature Sputtered Aluminum Nitride Films with Dissimilar Nanostructure

    Directory of Open Access Journals (Sweden)

    Cristina Besleaga

    2017-11-01

    Full Text Available Aluminum Nitride (AlN has been long time being regarded as highly interesting material for developing sensing applications (including biosensors and implantable sensors. AlN, due to its appealing electronic properties, is envisaged lately to serve as a multi-functional biosensing platform. Although generally exploited for its intrinsic piezoelectricity, its surface morphology and mechanical performance (elastic modulus, hardness, wear, scratch and tensile resistance to delamination, adherence to the substrate, corrosion resistance and cytocompatibility are also essential features for high performance sustainable biosensor devices. However, information about AlN suitability for such applications is rather scarce or at best scattered and incomplete. Here, we aim to deliver a comprehensive evaluation of the morpho-structural, compositional, mechanical, electrochemical and biological properties of reactive radio-frequency magnetron sputtered AlN nanostructured thin films with various degrees of c-axis texturing, deposited at a low temperature (~50 °C on Si (100 substrates. The inter-conditionality elicited between the base pressure level attained in the reactor chamber and crystalline quality of AlN films is highlighted. The potential suitability of nanostructured AlN (in form of thin films for the realization of various type of sensors (with emphasis on bio-sensors is thoroughly probed, thus unveiling its advantages and limitations, as well as suggesting paths to safely exploit the remarkable prospects of this type of materials.

  20. A peptide-based biological coating for enhanced corrosion resistance of titanium alloy biomaterials in chloride-containing fluids.

    Science.gov (United States)

    Muruve, Noah; Feng, Yuanchao; Platnich, Jaye; Hassett, Daniel; Irvin, Randall; Muruve, Daniel; Cheng, Frank

    2017-03-01

    Titanium alloys are common materials in the manufacturing of dental and orthopedic implants. Although these materials exhibit excellent biocompatibility, corrosion in response to biological fluids can impact prosthesis performance and longevity. In this work, a PEGylated metal binding peptide (D-K122-4-PEG), derived from bacteria Pseudomonas aeruginosa, was applied on a titanium (Ti) alloy, and the corrosion resistance of the coated alloy specimen was investigated in simulated chloride-containing physiological fluids by electrochemical impedance spectroscopy and micro-electrochemical measurements, surface characterization, and biocompatibility testing. Compared to uncoated specimen, the D-K122-4-PEG-coated Ti alloy demonstrates decreased corrosion current density without affecting the natural passivity. Morphological analysis using atomic force microscopy and scanning electron microscopy confirms a reduction in surface roughness of the coated specimens in the fluids. The D-K122-4-PEG does not affect the binding of HEK-293T cells to the surface of unpolished Ti alloy, nor does it increase the leukocyte activation properties of the metal. D-K122-4-PEG represents a promising coating to enhance the corrosion resistance of Ti alloys in physiological fluids, while maintaining an excellent biocompatibility.

  1. Corrosion of bare carbon steel as a passive sensor to assess moisture availability for biological activity in Atacama Desert soils.

    Science.gov (United States)

    Cáceres, Luis; Davila, Alfonso F; Soliz, Alvaro; Saldivia, Jessica

    2018-02-28

    Here we consider that the corrosion of polished bared metal coupons can be used as a passive sensor to detect or identify the lower limit of water availability suitable for biological activity in Atacama Desert soils or solid substrates. For this purpose, carbon steel coupons were deposited at selected sites along a west-east transect and removed at predetermined times for morphological inspection. The advantage of this procedure is that the attributes of the oxide layer (corrosion extent, morphology and oxide phases) can be considered as a fingerprint of the atmospheric moisture history at a given time interval. Two types of coupons were used, long rectangular shaped ones that were half-buried in a vertical position, and square shaped ones that were deposited on the soil surface. The morphological attributes observed by SEM inspection were found to correlate to the so-called humectation time which is determined from local meteorological parameters. The main finding was that the decreasing trend of atmospheric moisture along the transect was closely related to corrosion behaviour and water soil penetration. For instance, at the coastal site oxide phases formed on the coupon surface rapidly evolve into well-crystallized species, while at the driest inland site Lomas Bayas only amorphous oxide was observed on the coupons.

  2. Receptor-Mediated Endocytosis and Brain Delivery of Therapeutic Biologics

    Directory of Open Access Journals (Sweden)

    Guangqing Xiao

    2013-01-01

    Full Text Available Transport of macromolecules across the blood-brain-barrier (BBB requires both specific and nonspecific interactions between macromolecules and proteins/receptors expressed on the luminal and/or the abluminal surfaces of the brain capillary endothelial cells. Endocytosis and transcytosis play important roles in the distribution of macromolecules. Due to the tight junction of BBB, brain delivery of traditional therapeutic proteins with large molecular weight is generally not possible. There are multiple pathways through which macromolecules can be taken up into cells through both specific and nonspecific interactions with proteins/receptors on the cell surface. This review is focused on the current knowledge of receptor-mediated endocytosis/transcytosis and brain delivery using the Angiopep-2-conjugated system and the molecular Trojan horses. In addition, the role of neonatal Fc receptor (FcRn in regulating the efflux of Immunoglobulin G (IgG from brain to blood, and approaches to improve the pharmacokinetics of therapeutic biologics by generating Fc fusion proteins, and increasing the pH dependent binding affinity between Fc and FcRn, are discussed.

  3. Protease activated receptors (PARS) mediation in gyroxin biological activity

    International Nuclear Information System (INIS)

    Silva, Jose Alberto Alves da

    2009-01-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH 2 , respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  4. Embryo fossilization is a biological process mediated by microbial biofilms.

    Science.gov (United States)

    Raff, Elizabeth C; Schollaert, Kaila L; Nelson, David E; Donoghue, Philip C J; Thomas, Ceri-Wyn; Turner, F Rudolf; Stein, Barry D; Dong, Xiping; Bengtson, Stefan; Huldtgren, Therese; Stampanoni, Marco; Chongyu, Yin; Raff, Rudolf A

    2008-12-09

    Fossilized embryos with extraordinary cellular preservation appear in the Late Neoproterozoic and Cambrian, coincident with the appearance of animal body fossils. It has been hypothesized that microbial processes are responsible for preservation and mineralization of organic tissues. However, the actions of microbes in preservation of embryos have not been demonstrated experimentally. Here, we show that bacterial biofilms assemble rapidly in dead marine embryos and form remarkable pseudomorphs in which the bacterial biofilm replaces and exquisitely models details of cellular organization and structure. The experimental model was the decay of cleavage stage embryos similar in size and morphology to fossil embryos. The data show that embryo preservation takes place in 3 distinct steps: (i) blockage of autolysis by reducing or anaerobic conditions, (ii) rapid formation of microbial biofilms that consume the embryo but form a replica that retains cell organization and morphology, and (iii) bacterially catalyzed mineralization. Major bacterial taxa in embryo decay biofilms were identified by using 16S rDNA sequencing. Decay processes were similar in different taphonomic conditions, but the composition of bacterial populations depended on specific conditions. Experimental taphonomy generates preservation states similar to those in fossil embryos. The data show how fossilization of soft tissues in sediments can be mediated by bacterial replacement and mineralization, providing a foundation for experimentally creating biofilms from defined microbial species to model fossilization as a biological process.

  5. Eddy-mediated biological productivity in the Bay of Bengal during fall and spring intermonsoons

    Digital Repository Service at National Institute of Oceanography (India)

    PrasannaKumar, S.; Nuncio, M.; Ramaiah, N.; Sardesai, S.; Narvekar, J.; Fernandes, V.; Paul, J.T.

    -1 Eddy-mediated biological productivity in the Bay of Bengal during fall and spring intermonsoons S. Prasanna Kumar, M. Nuncio, N. Ramaiah, S. Sardesai, Jayu Narvekar, Veronica Fernandes, Jane T. Paul National Institute of Oceanography, Dona Paula...

  6. Future strategy and puzzles of heavy ion beam mediated technique in genetic improvement of biological bodies

    International Nuclear Information System (INIS)

    Huang Qunce

    2007-01-01

    The 7 research puzzles in the genetic improvement of biological bodies made by ion beam mediated technique, are worth noticed. The technical ideas, including one mediated technique in physics, 2 significant subjects, 3 effective changes, the mediated evidences of 4 aspects and 5 biological characteristics, were particularly put forward according to the existing states in the field. The 2 significant subjects consist of the mechanics of the allogenetic materials entering into the acceptor and they being to be recombined. The 3 effective changes include from studying morphology to genetic laws, from researching M1 generation to the next generations, from determining the single character to the synthetic traits. The mediated evidences of 4 aspects come from morphology, physiology and biochemistry, molecule biology. The 5 biological characteristics are mainly reproduction, development, photosynthesis, bad condition-resistant and quality. (authors)

  7. Corrosion and corrosion control

    International Nuclear Information System (INIS)

    Khanna, A.S.; Totlani, M.K.

    1995-01-01

    Corrosion has always been associated with structures, plants, installations and equipment exposed to aggressive environments. It effects economy, safety and product reliability. Monitoring of component corrosion has thus become an essential requirement for the plant health and safety. Protection methods such as appropriate coatings, cathodic protection and use of inhibitors have become essential design parameters. High temperature corrosion, especially hot corrosion, is still a difficult concept to accommodate in corrosion allowance; there is a lack of harmonized system of performance testing of materials at high temperatures. In order to discuss and deliberate on these aspects, National Association for Corrosion Engineers International organised a National Conference on Corrosion and its Control in Bombay during November 28-30, 1995. This volume contains papers presented at the symposium. Paper relevant to INIS is indexed separately. refs., figs., tabs

  8. A novel theory: biological processes mostly involve two types of mediators, namely general and specific mediators Endogenous small radicals such as superoxide and nitric oxide may play a role of general mediator in biological processes.

    Science.gov (United States)

    Mo, Jian

    2005-01-01

    A great number of papers have shown that free radicals as well as bioactive molecules can play a role of mediator in a wide spectrum of biological processes, but the biological actions and chemical reactivity of the free radicals are quite different from that of the bioactive molecules, and that a wide variety of bioactive molecules can be easily modified by free radicals due to having functional groups sensitive to redox, and the significance of the interaction between the free radicals and the bioactive molecules in biological processes has been confirmed by the results of some in vitro and in vivo studies. Based on these evidence, this article presented a novel theory about the mediators of biological processes. The essentials of the theory are: (a) mediators of biological processes can be classified into general and specific mediators; the general mediators include two types of free radicals, namely superoxide and nitric oxide; the specific mediators include a wide variety of bioactive molecules, such as specific enzymes, transcription factors, cytokines and eicosanoids; (b) a general mediator can modify almost any class of the biomolecules, and thus play a role of mediator in nearly every biological process via diverse mechanisms; a specific mediator always acts selectively on certain classes of the biomolecules, and may play a role of mediator in different biological processes via a same mechanism; (c) biological processes are mostly controlled by networks of their mediators, so the free radicals can regulate the last consequence of a biological process by modifying some types of the bioactive molecules, or in cooperation with these bioactive molecules; the biological actions of superoxide and nitric oxide may be synergistic or antagonistic. According to this theory, keeping the integrity of these networks and the balance between the free radicals and the bioactive molecules as well as the balance between the free radicals and the free radical scavengers

  9. Click chemistry mediated functionalization of vertical nanowires for biological applications

    DEFF Research Database (Denmark)

    Vutti, Surendra; Schoffelen, Sanne; Bolinsson, Jessica

    2016-01-01

    is of general interest for biological studies. The attachment of a peptide substrate provided NW arrays for the detection of protease activity. In addition, green fluorescent protein was immobilized in a site-specific manner and recognized by antibody binding to demonstrate the proof-of-concept for the use...

  10. Performance of a Yeast-mediated Biological Fuel Cell

    Directory of Open Access Journals (Sweden)

    Filip To

    2008-10-01

    Full Text Available Saccharomyces cerevisiae present in common Baker’s yeast was used in a microbial fuel cell in which glucose was the carbon source. Methylene blue was used as the electronophore in the anode compartment, while potassium ferricyanide and methylene blue were tested as electron acceptors in the cathode compartment. Microbes in a mediator-free environment were used as the control. The experiment was performed in both open and closed circuit configurations under different loads ranging from 100 kΩ to 400Ω. The eukaryotic S. cerevisiae-based fuel cell showed improved performance when methylene blue and ferricyanide were used as electron mediators, rendering a maximum power generation of 146.71±7.7 mW/m3. The fuel cell generated a maximum open circuit voltage of 383.6±1.5 mV and recorded a maximum efficiency of 28±1.8 % under 100 kΩ of external load.

  11. Waist circumference as a mediator of biological maturation effect on the motor coordination in children.

    Science.gov (United States)

    Luz, Leonardo G O; Seabra, André; Padez, Cristina; Duarte, João P; Rebelo-Gonçalves, Ricardo; Valente-Dos-Santos, João; Luz, Tatiana D D; Carmo, Bruno C M; Coelho-E-Silva, Manuel

    2016-09-01

    The present study aimed to: 1) examine the association of biological maturation effect on children's performance at a motor coordination battery and 2) to assess whether the association between biological maturation and scores obtained in motor coordination tests is mediated by some anthropometric measurement. The convenience sample consisted of 73 male children aged 8 years old. Anthropometric data considered the height, body mass, sitting height, waist circumference, body mass index, fat mass and fat-free mass estimates. Biological maturation was assessed by the percentage of the predicted mature stature. Motor coordination was tested by the Körperkoordinationstest für Kinder. A partial correlation between anthropometric measurements, z-score of maturation and the motor coordination tests were performed, controlling for chronological age. Finally, causal mediation analysis was performed. Height, body mass, waist circumference and fat mass showed a slight to moderate inverse correlation with motor coordination. Biological maturation was significantly associated with the balance test with backward walking (r=-0.34). Total mediation of the waist circumference was identified in the association between biological maturation and balance test with backward walking (77%). We identified an association between biological maturation and KTK test performance in male children and also verified that there is mediation of waist circumference. It is recommended that studies be carried out with female individuals and at other age ranges. Copyright © 2016 Sociedade de Pediatria de São Paulo. Publicado por Elsevier Editora Ltda. All rights reserved.

  12. Click Chemistry Mediated Functionalization of Vertical Nanowires for Biological Applications.

    Science.gov (United States)

    Vutti, Surendra; Schoffelen, Sanne; Bolinsson, Jessica; Buch-Månson, Nina; Bovet, Nicolas; Nygård, Jesper; Martinez, Karen L; Meldal, Morten

    2016-01-11

    Semiconductor nanowires (NWs) are gaining significant importance in various biological applications, such as biosensing and drug delivery. Efficient and controlled immobilization of biomolecules on the NW surface is crucial for many of these applications. Here, we present for the first time the use of the Cu(I) -catalyzed alkyne-azide cycloaddition and its strain-promoted variant for the covalent functionalization of vertical NWs with peptides and proteins. The potential of the approach was demonstrated in two complementary applications of measuring enzyme activity and protein binding, which is of general interest for biological studies. The attachment of a peptide substrate provided NW arrays for the detection of protease activity. In addition, green fluorescent protein was immobilized in a site-specific manner and recognized by antibody binding to demonstrate the proof-of-concept for the use of covalently modified NWs for diagnostic purposes using minute amounts of material. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. MgF2-coated porous magnesium/alumina scaffolds with improved strength, corrosion resistance, and biological performance for biomedical applications.

    Science.gov (United States)

    Kang, Min-Ho; Jang, Tae-Sik; Kim, Sung Won; Park, Hui-Sun; Song, Juha; Kim, Hyoun-Ee; Jung, Kyung-Hwan; Jung, Hyun-Do

    2016-05-01

    Porous magnesium (Mg) has recently emerged as a promising biodegradable alternative to biometal for bone ingrowth; however, its low mechanical properties and high corrosion rate in biological environments remain problematic. In this study, porous magnesium was implemented in a scaffold that closely mimics the mechanical properties of human bones with a controlled degradation rate and shows good biocompatibility to match the regeneration rate of bone tissue at the affected site. The alumina-reinforced Mg scaffold was produced by spark plasma sintering and coated with magnesium fluoride (MgF2) using a hydrofluoric acid solution to regulate the corrosion rate under physiological conditions. Sodium chloride granules (NaCl), acting as space holders, were leached out to achieve porous samples (60%) presenting an average pore size of 240 μm with complete pore interconnectivity. When the alumina content increased from 0 to 5 vol%, compressive strength and stiffness rose considerably from 9.5 to 13.8 MPa and from 0.24 to 0.40 GPa, respectively. Moreover, the biological response evaluated by in vitro cell test and blood test of the MgF2-coated porous Mg composite was enhanced with better corrosion resistance compared with that of uncoated counterparts. Consequently, MgF2-coated porous Mg/alumina composites may be applied in load-bearing biodegradable implants. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. The corrosion and biological behaviour of titanium alloys in the presence of human lymphoid cells and MC3T3-E1 osteoblasts

    International Nuclear Information System (INIS)

    Zhang Yumei; Zhao Yimin; Chai Feng; Hildebrand, Hartmut F; Hornez, Jean-Christophe; Li, Chang Liang; Traisnel, Michel

    2009-01-01

    Corrosion behaviour of biomedical alloys is generally determined in mineral electrolytes: unbuffered NaCl 0.9% (pH 7.4) or artificial saliva (pH 6.8). The assays with exclusive utilization of these electrolytes are of low relevance for the biological condition, to which the alloys will be exposed once implanted in the human organism. As an approach to the biological situation regarding the interaction of proteins, electrolytes and metals, we added the RPMI cell culture medium containing foetal calf serum as a biological electrolyte (pH 7.0). The analysis of corrosion behaviour was also performed in the presence of human lymphoid cells (CEM). The rest potential (E r ) and the global polarization were determined on cp-Ti, micro-arc oxidized cp-Ti (MAO-Ti), four different Ti-alloys (Ti6Al4V, Ti12Zr, Ti(AlMoZr), Ti(NbTaZr)) and 316L stainless steel. The 316L exhibited an appropriate E r and a good passive current density (I p ), but a high corrosion potential (E c ) and a very low breakdown potential (E b ) in all electrolytes. All Ti-alloys exhibited a much better electrochemical behaviour: better E r and E c and very high E b . No significant differences of the above parameters existed between the Ti-alloys, except for Zr-containing alloys that showed better corrosion behaviour. A remarkable difference, however, was stated with respect to the electrolytes. NaCl 0.9% induced strong variations between the Ti-alloys. More homogeneous results were obtained with artificial saliva and RPMI medium, which induced a favourable E c and an increased I p . The presence of cells further decreased these values. The unbuffered NaCl solution seems to be less appropriate for the analysis of corrosion of metals. Additional in vitro biological assessments with CEM cell suspensions and MC3T3-E1 osteoblasts confirmed the advantages of the Ti(AlMoZr) and Ti(NbTaZr) alloys with an improved cell proliferation and vitality rate.

  15. The corrosion and biological behaviour of titanium alloys in the presence of human lymphoid cells and MC3T3-E1 osteoblasts.

    Science.gov (United States)

    Zhang, Yu Mei; Chai, Feng; Hornez, Jean-Christophe; Li, Chang Liang; Zhao, Yi Min; Traisnel, Michel; Hildebrand, Hartmut F

    2009-02-01

    Corrosion behaviour of biomedical alloys is generally determined in mineral electrolytes: unbuffered NaCl 0.9% (pH 7.4) or artificial saliva (pH 6.8). The assays with exclusive utilization of these electrolytes are of low relevance for the biological condition, to which the alloys will be exposed once implanted in the human organism. As an approach to the biological situation regarding the interaction of proteins, electrolytes and metals, we added the RPMI cell culture medium containing foetal calf serum as a biological electrolyte (pH 7.0). The analysis of corrosion behaviour was also performed in the presence of human lymphoid cells (CEM). The rest potential (Er) and the global polarization were determined on cp-Ti, micro-arc oxidized cp-Ti (MAO-Ti), four different Ti-alloys (Ti6Al4V, Ti12Zr, Ti(AlMoZr), Ti(NbTaZr)) and 316L stainless steel. The 316L exhibited an appropriate Er and a good passive current density (Ip), but a high corrosion potential (Ec) and a very low breakdown potential (Eb) in all electrolytes. All Ti-alloys exhibited a much better electrochemical behaviour: better Er and Ec and very high Eb. No significant differences of the above parameters existed between the Ti-alloys, except for Zr-containing alloys that showed better corrosion behaviour. A remarkable difference, however, was stated with respect to the electrolytes. NaCl 0.9% induced strong variations between the Ti-alloys. More homogeneous results were obtained with artificial saliva and RPMI medium, which induced a favourable Ec and an increased Ip. The presence of cells further decreased these values. The unbuffered NaCl solution seems to be less appropriate for the analysis of corrosion of metals. Additional in vitro biological assessments with CEM cell suspensions and MC3T3-E1 osteoblasts confirmed the advantages of the Ti(AlMoZr) and Ti(NbTaZr) alloys with an improved cell proliferation and vitality rate.

  16. The corrosion and biological behaviour of titanium alloys in the presence of human lymphoid cells and MC3T3-E1 osteoblasts

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yumei; Zhao Yimin [School of Stomatology, Fourth Military Medical University, Xi' an 710032 (China); Chai Feng; Hildebrand, Hartmut F [Groupe de Recherche sur les Biomateriaux, Faculte de Medecine, F-59045 Lille cedex (France); Hornez, Jean-Christophe [Laboratoire des Materiaux et Procedes (LMP), EA 2443, UVHC, 59600 Maubeuge (France); Li, Chang Liang [Northwest Institute for Nonferrous Metal Research, Xi' an 710016 (China); Traisnel, Michel, E-mail: zhaoym@fmmu.edu.c, E-mail: fhildebrand@univ-lille2.f [Ecole Nationale Superieure de Chimie de Lille, UMR CNRS 8008, 59652 Villeneuve d' Ascq (France)

    2009-02-15

    Corrosion behaviour of biomedical alloys is generally determined in mineral electrolytes: unbuffered NaCl 0.9% (pH 7.4) or artificial saliva (pH 6.8). The assays with exclusive utilization of these electrolytes are of low relevance for the biological condition, to which the alloys will be exposed once implanted in the human organism. As an approach to the biological situation regarding the interaction of proteins, electrolytes and metals, we added the RPMI cell culture medium containing foetal calf serum as a biological electrolyte (pH 7.0). The analysis of corrosion behaviour was also performed in the presence of human lymphoid cells (CEM). The rest potential (E{sub r}) and the global polarization were determined on cp-Ti, micro-arc oxidized cp-Ti (MAO-Ti), four different Ti-alloys (Ti6Al4V, Ti12Zr, Ti(AlMoZr), Ti(NbTaZr)) and 316L stainless steel. The 316L exhibited an appropriate E{sub r} and a good passive current density (I{sub p}), but a high corrosion potential (E{sub c}) and a very low breakdown potential (E{sub b}) in all electrolytes. All Ti-alloys exhibited a much better electrochemical behaviour: better E{sub r} and E{sub c} and very high E{sub b}. No significant differences of the above parameters existed between the Ti-alloys, except for Zr-containing alloys that showed better corrosion behaviour. A remarkable difference, however, was stated with respect to the electrolytes. NaCl 0.9% induced strong variations between the Ti-alloys. More homogeneous results were obtained with artificial saliva and RPMI medium, which induced a favourable E{sub c} and an increased I{sub p}. The presence of cells further decreased these values. The unbuffered NaCl solution seems to be less appropriate for the analysis of corrosion of metals. Additional in vitro biological assessments with CEM cell suspensions and MC3T3-E1 osteoblasts confirmed the advantages of the Ti(AlMoZr) and Ti(NbTaZr) alloys with an improved cell proliferation and vitality rate.

  17. Corrosion cracking

    International Nuclear Information System (INIS)

    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

  18. Unsaturated Glycerophospholipids Mediate Heme Crystallization: Biological Implications for Hemozoin Formation in the Kissing Bug Rhodnius prolixus

    DEFF Research Database (Denmark)

    Stiebler, R.; Majerowicz, David; Knudsen, Jens

    2014-01-01

    (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient beta....... beta-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those......PE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, beta-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus...

  19. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    transport anciens dont il a fallu remplacer les panneaux extrados en raison de is corrosion profonde des lisses. Ce type d’avion a etc mis en service h partir...as six years) where lavatories are placed above the lower section of the aft pressure dome bulkhead (fig.8)., corrosion Is found in the bulkhead web ...due to leakage of toilet fluids. One of the most severe corrosion ever found In this area was with the corrosion completely penetrated through the web

  20. Omeprazole impairs vascular redox biology and causes xanthine oxidoreductase-mediated endothelial dysfunction

    Directory of Open Access Journals (Sweden)

    Lucas C. Pinheiro

    2016-10-01

    Full Text Available Proton pump inhibitors (PPIs are widely used drugs that may increase the cardiovascular risk by mechanisms not entirely known. While PPIs increase asymmetric dimethylarginine (ADMA levels and inhibit nitric oxide production, it is unknown whether impaired vascular redox biology resulting of increased xanthine oxidoreductase (XOR activity mediates PPIs-induced endothelial dysfunction (ED. We examined whether increased XOR activity impairs vascular redox biology and causes ED in rats treated with omeprazole. We also examined whether omeprazole aggravates the ED found in hypertension. Treatment with omeprazole reduced endothelium-dependent aortic responses to acetylcholine without causing hypertension. However, omeprazole did not aggravate two-kidney, one-clip (2K1C hypertension, nor hypertension-induced ED. Omeprazole and 2K1C increased vascular oxidative stress as assessed with dihydroethidium (DHE, which reacts with superoxide, and by the lucigenin chemiluminescence assay. The selective XOR inhibitor febuxostat blunted both effects induced by omeprazole. Treatment with omeprazole increased plasma ADMA concentrations, XOR activity and systemic markers of oxidative stress. Incubation of aortic rings with ADMA increased XOR activity, DHE fluorescence and lucigenin chemiluminescence signals, and febuxostat blunted these effects. Providing functional evidence that omeprazole causes ED by XOR-mediated mechanisms, we found that febuxostat blunted the ED caused by omeprazole treatment. This study shows that treatment with omeprazole impairs the vascular redox biology by XOR-mediated mechanisms leading to ED. While omeprazole did not further impair hypertension-induced ED, further studies in less severe animal models are warranted. Our findings may have major relevance, particularly to patients with cardiovascular diseases taking PPIs.

  1. Pitting corrosion

    International Nuclear Information System (INIS)

    Allgaier, W.

    1985-01-01

    Pitting corrosion is a kind of electrolytic corrosion by which the surface of a material is locally affected owing to inhomogeneities on the part of the material or medium. The paper deals briefly with questions relating to the importance, to parameters medium or materialwise, influence on production and construction, as well as the general conditions for pitting corrosion. In particular oxygen corrosion in unalloyed and low-alloy steel, and pitting corrosion in ferritic chromium-steel and austenitic chromium-nickel (molybdenum) steel is described. (DG) [de

  2. The Mediating Role of Physical Self-Concept on Relations between Biological Maturity Status and Physical Activity in Adolescent Females

    Science.gov (United States)

    Cumming, Sean P.; Standage, Martyn; Loney, Tom; Gammon, Catherine; Neville, Helen; Sherar, Lauren B.; Malina, Robert M.

    2011-01-01

    The current study examined the mediating role of physical self-concept on relations between biological maturity status and self-reported physical activity in adolescent British females. Biological maturity status, physical self-concept and physical activity were assessed in 407 female British year 7-9 pupils (M age = 13.2 years, SD = 1.0).…

  3. Biological fate of cobalt-60 released during the corrosion of neutron-activated stanless steel in seawater

    International Nuclear Information System (INIS)

    Young, J.S.

    1982-03-01

    Passing seawater over radioactive Type 347 stainless steel in a sediment/seawater laboratory system and exposing marine animals to this environment provided information on the bioaccumulation of 60 Co from radioactive structural material. Exposure of marine organisms to radioactive corrosion products and directly to radioactive stainless steel in seawater simulated some of the possible conditions which could arise from the deposition of radioactive stainless steel on the ocean floor. Detectable levels of 60 Co in marine animals were not observed on a short term basis (5 weeks). Longterm (13 months) exposure of marine animals in a sediment/seawater system resulted in 60 Co bioaccumulation. The specific activity of 60 Co in the organisms was as much as one million times less than that initially present in the radioactive stainless steel. This was due to the dilution of 60 Co by stable cobalt in the seawater, sediments and organisms. As expected the 60 Co specific activity of the organisms never increased above that of the radioactive source. This is because 60 Co is chemicaly indistinguishable from stable Co. Increasing 60 Co concentration factors with decreasing 60 Co concentrations in the seawater and sediment media coupled with relatively constant 60 Co specific activities suggest a possible homeostatic control of cobalt concentrations in certain marine organisms. The evidence indicates that the marine animals derived more of the accumulated 60 Co from the sediments and interstitial water than from seawater. Cobalt-60 concentration factors were generally found to be lower than published cobalt concentration factors due to the predominantly insoluble nature of the corrosion products. Baseline information is provided on trace element concentrations in deep-sea organisms. Stable Co and twenty other elements were measured in abyssal invertebrates and a fish

  4. Mechanical, In Vitro Corrosion Resistance and Biological Compatibility of Cast and Annealed Ti25Nb10Zr Alloy

    Directory of Open Access Journals (Sweden)

    Cosmin M. Cotrut

    2017-03-01

    Full Text Available Compared to other alloys, Ti6Al4V is the most used in medicine. In recent years, concerns regarding the toxicity of Al and V elements found in the composition of Ti6Al4V have drawn the attention of the scientific community, due to the release of Al or V ions after long term exposure to human body fluids which can lead to a negative response of the human host. Based on this, the aim of the paper was to manufacture a Ti25Nb10Zr alloy consisting of biocompatible elements which can replace Ti6Al4V usage in medical applications. In order to prove that this alloy possessed improved properties, the mechanical, wear and corrosion resistance, wettability, and cell viability were performed in comparison with those of the Ti6Al4V alloy. The corrosion behavior of this new alloy in simulated body fluid (SBF and Hank solutions is superior to that of Ti6Al4V. The cast Ti25Nb10Zr alloy has a good tribological performance in SBF, while annealed Ti25Nb10Zr alloy is better in Hank solution. Cell viability and proliferation assay after five days indicated that Ti25Nb10Zr presented a good viability and proliferation with values of approximately 7% and 10% higher, respectively, than the ones registered for pure Ti. When compared with Ti6Al4V, the obtained results for Ti25Nb10Zr indicated smaller values with 20% in the case of both tests. Overall, it can be concluded that cell proliferation and viability tests indicated that the biocompatibility of the Ti25Nb10Zr alloy is as good as pure Ti and Ti6Al4V alloy.

  5. Corrosion protection

    Science.gov (United States)

    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.

  6. Role of Muramyl Dipeptide in Lipopolysaccharide-Mediated Biological Activity and Osteoclast Activity

    Directory of Open Access Journals (Sweden)

    Hideki Kitaura

    2018-01-01

    Full Text Available Lipopolysaccharide (LPS is an endotoxin and bacterial cell wall component that is capable of inducing inflammation and immunological activity. Muramyl dipeptide (MDP, the minimal essential structural unit responsible for the immunological activity of peptidoglycans, is another inflammation-inducing molecule that is ubiquitously expressed by bacteria. Several studies have shown that inflammation-related biological activities were synergistically induced by interactions between LPS and MDP. MDP synergistically enhances production of proinflammatory cytokines that are induced by LPS exposure. Injection of MDP induces lethal shock in mice challenged with LPS. LPS also induces osteoclast formation and pathological bone resorption; MDP enhances LPS induction of both processes. Furthermore, MDP enhances the LPS-induced receptor activator of NF-κB ligand (RANKL expression and toll-like receptor 4 (TLR4 expression both in vivo and in vitro. Additionally, MDP enhances LPS-induced mitogen-activated protein kinase (MAPK signaling in stromal cells. Taken together, these findings suggest that MDP plays an important role in LPS-induced biological activities. This review discusses the role of MDP in LPS-mediated biological activities, primarily in relation to osteoclastogenesis.

  7. Using biological and physico-chemical test methods to assess the role of concrete mixture design in resistance to microbially induced corrosion

    Science.gov (United States)

    House, Mitchell Wayne

    Concrete is the most widely used material for construction of wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated portland cement make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multi-stage degradation process known as microbially induced corrosion, or MIC. MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur oxidizing bacteria Thiobacillus that resides on concrete surfaces above the waterline. Sulfuric acid then attacks the cement paste portion of the concrete matrix through decalcification of calcium hydroxide and calcium silica hydrate coupled with the formation of expansive corrosion products. The attack proceeds inward resulting in reduced service life and potential failure of the concrete structure. There are several challenges associated with assessing a concrete's susceptibility to MIC. First, no standard laboratory tests exist to assess concrete resistance to MIC. Straightforward reproduction of MIC in the laboratory is complicated by the use of microorganisms and hydrogen sulfide gas. Physico-chemical tests simulating MIC by immersing concrete specimens in sulfuric acid offer a convenient alternative, but do not accurately capture the damage mechanisms associated with biological corrosion. Comparison of results between research studies is difficult due to discrepancies that can arise in experimental methods even if current ASTM standards are followed. This thesis presents two experimental methods to evaluate concrete resistance to MIC: one biological and one physico-chemical. Efforts are made to address the critical aspects of each testing method currently absent in the literature. The first method presented is a new test

  8. Mediating factors of land use change among coffee farmers in a biological corridor

    DEFF Research Database (Denmark)

    Bosselmann, Aske Skovmand

    2012-01-01

    . Additional 224 telephone interviews supplement the data on land use change. Results show a 50% reduction in the coffee area and a corresponding loss of trees. Family labor, age of household head, coffee prices, and use of shade tree products significantly reduce the probability of converting the coffee field......, while the number of family members engaged in other agriculture and non-farm work increases the probability. A stronger tie to coffee farming is found to abate the influence of underlying drivers, whereas the younger generation downgrades the labor intensive coffee farming. Payments for environmental......Trees in agricultural landscapes are important for the provision of environmental services. This study assesses the loss of shade coffee during a 9 year period in a biological corridor in Costa Rica, and investigates the mediating factors of land use change. Following a conceptual framework...

  9. Corrosion Engineering.

    Science.gov (United States)

    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…

  10. Biological effects of mutant ceruloplasmin on hepcidin-mediated internalization of ferroportin.

    Science.gov (United States)

    Kono, Satoshi; Yoshida, Kenichi; Tomosugi, Naohisa; Terada, Tatsuhiro; Hamaya, Yasushi; Kanaoka, Shigeru; Miyajima, Hiroaki

    2010-11-01

    Ceruloplasmin plays an essential role in cellular iron efflux by oxidizing ferrous iron exported from ferroportin. Ferroportin is posttranslationally regulated through internalization triggered by hepcidin binding. Aceruloplasminemia is an autosomal recessive disorder of iron homeostasis resulting from mutations in the ceruloplasmin gene. The present study investigated the biological effects of glycosylphosphatidylinositol (GPI)-linked ceruloplasmin on the hepcidin-mediated internalization of ferroportin. The prevention of hepcidin-mediated ferroportin internalization was observed in the glioma cells lines expressing endogenous ceruloplasmin as well as in the cells transfected with GPI-linked ceruloplasmin under low levels of hepcidin. A decrease in the extracellular ferrous iron by an iron chelator and incubation with purified ceruloplasmin in the culture medium prevented hepcidin-mediated ferroportin internalization, while the reconstitution of apo-ceruloplasmin was not able to prevent ferroportin internalization. The effect of ceruloplasmin on the ferroportin stability was impaired due to three distinct properties of the mutant ceruloplasmin: namely, a decreased ferroxidase activity, the mislocalization in the endoplasmic reticulum, and the failure of copper incorporation into apo-ceruloplasmin. Patients with aceruloplasminemia exhibited low serum hepcidin levels and a decreased ferroportin protein expression in the liver. The in vivo findings supported the notion that under low levels of hepcidin, mutant ceruloplasmin cannot stabilize ferroportin because of a loss-of-function in the ferroxidase activity, which has been reported to play an important role in the stability of ferroportin. The properties of mutant ceruloplasmin regarding the regulation of ferroportin may therefore provide a therapeutic strategy for aceruloplasminemia patients. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Unsaturated Glycerophospholipids Mediate Heme Crystallization: Biological Implications for Hemozoin Formation in the Kissing Bug Rhodnius prolixus

    Science.gov (United States)

    Stiebler, Renata; Majerowicz, David; Knudsen, Jens; Gondim, Katia C.; Wright, David W.; Egan, Timothy J.; Oliveira, Marcus F.

    2014-01-01

    Hemozoin (Hz) is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus, Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM). Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML) in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE) and phosphatidylcholine (uPC), with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9–17.7 minutes) than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut. PMID:24586467

  12. Unsaturated glycerophospholipids mediate heme crystallization: biological implications for hemozoin formation in the kissing bug Rhodnius prolixus.

    Directory of Open Access Journals (Sweden)

    Renata Stiebler

    Full Text Available Hemozoin (Hz is a heme crystal produced by some blood-feeding organisms, as an efficient way to detoxify heme derived from hemoglobin digestion. In the triatomine insect Rhodnius prolixus, Hz is essentially produced by midgut extracellular phospholipid membranes known as perimicrovillar membranes (PMVM. Here, we investigated the role of commercial glycerophospholipids containing serine, choline and ethanolamine as headgroups and R. prolixus midgut lipids (RML in heme crystallization. All commercial unsaturated forms of phospholipids, as well as RML, mediated fast and efficient β-hematin formation by means of two kinetically distinct mechanisms: an early and fast component, followed by a late and slow one. The fastest reactions observed were induced by unsaturated forms of phosphatidylethanolamine (uPE and phosphatidylcholine (uPC, with half-lives of 0.04 and 0.7 minutes, respectively. β-hematin crystal morphologies were strikingly distinct among groups, with uPE producing homogeneous regular brick-shaped crystals. Interestingly, uPC-mediated reactions resulted in two morphologically distinct crystal populations: one less representative group of regular crystals, resembling those induced by uPE, and the other largely represented by crystals with numerous sharp edges and tapered ends. Heme crystallization reactions induced by RML were efficient, with a heme to β-hematin conversion rate higher than 70%, but clearly slower (t1/2 of 9.9-17.7 minutes than those induced by uPC and uPE. Interestingly, crystals produced by RML were homogeneous in shape and quite similar to those mediated by uPE. Thus, β-hematin formation can be rapidly and efficiently induced by unsaturated glycerophospholipids, particularly uPE and uPC, and may play a role on biological heme crystallization in R. prolixus midgut.

  13. Fungus-mediated biological synthesis of gold nanoparticles: potential in detection of liver cancer

    Science.gov (United States)

    Chauhan, Arun; Zubair, Swaleha; Tufail, Saba; Sherwani, Asif; Sajid, Mohammad; Raman, Suri C; Azam, Amir; Owais, Mohammad

    2011-01-01

    Background Nanomaterials are considered to be the pre-eminent component of the rapidly advancing field of nanotechnology. However, developments in the biologically inspired synthesis of nanoparticles are still in their infancy and consequently attracting the attention of material scientists throughout the world. Keeping in mind the fact that microorganism-assisted synthesis of nanoparticles is a safe and economically viable prospect, in the current study we report Candida albicans-mediated biological synthesis of gold nanoparticles. Methods and results Transmission electron microscopy, atomic force microscopy, and various spectrophotometric analyses were performed to characterize the gold nanoparticles. The morphology of the synthesized gold particles depended on the abundance of C. albicans cytosolic extract. Transmission electron microscopy, nanophox particle analysis, and atomic force microscopy revealed the size of spherical gold nanoparticles to be in the range of 20–40 nm and nonspherical gold particles were found to be 60–80 nm. We also evaluated the potential of biogenic gold nanoparticles to probe liver cancer cells by conjugating them with liver cancer cell surface-specific antibodies. The antibody-conjugated gold particles were found to bind specifically to the surface antigens of the cancer cells. Conclusion The antibody-conjugated gold particles synthesized in this study could successfully differentiate normal cell populations from cancerous cells. PMID:22072868

  14. RANTES/CCL5 mediated-biological effects depend on the syndecan-4/PKCα signaling pathway

    Directory of Open Access Journals (Sweden)

    Loïc Maillard

    2014-09-01

    Full Text Available The perpetuation of angiogenesis is involved in certain chronic inflammatory diseases. The accelerated neovascularisation may result from an inflammatory status with a response of both endothelial cells and monocytes to inflammatory mediators such as chemokines. We have previously described in vitro and in vivo the pro-angiogenic effects of the chemokine Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES/CCL5. The effects of RANTES/CCL5 may be related to its binding to G protein-coupled receptors and to proteoglycans such as syndecan-1 and -4. The aim of this study was to evaluate the functionality of syndecan-4 as a co-receptor of RANTES/CCL5 by the use of mutated syndecan-4 constructs. Our data demonstrate that site-directed mutations in syndecan-4 modify RANTES/CCL5 biological activities in endothelial cells. The SDC4S179A mutant, associated with an induced protein kinase C (PKCα activation, leads to higher RANTES/CCL5 pro-angiogenic effects, whereas the SDC4L188QQ and the SDC4A198del mutants, leading to lower phosphatidylinositol 4,5-bisphosphate (PIP2 binding or to lower PDZ protein binding respectively, are associated with reduced RANTES/CCL5 cellular effects. Moreover, our data highlight that the intracellular domain of SDC-4 is involved in RANTES/CCL5-induced activation of the PKCα signaling pathway and biological effect. As RANTES/CCL5 is involved in various physiopathological processes, the development of a new therapeutic strategy may be reliant on the mechanism by which RANTES/CCL5 exerts its biological activities, for example by targeting the binding of the chemokine to its proteoglycan receptor.

  15. Mechanisms Mediating the Biologic Activity of Synthetic Proline, Glycine, and Hydroxyproline Polypeptides in Human Neutrophils

    Science.gov (United States)

    Weinberger, Barry; Hanna, Nazeeh; Laskin, Jeffrey D.; Heck, Diane E.; Gardner, Carol R.; Gerecke, Donald R.; Laskin, Debra L.

    2005-01-01

    The accumulation of neutrophils at sites of tissue injury or infection is mediated by chemotactic factors released as part of the inflammatory process. Some of these factors are generated as a direct consequence of tissue injury or infection, including degradation fragments of connective tissue collagen and bacterial- or viral-derived peptides containing collagen-related structural motifs. In these studies, we examined biochemical mechanisms mediating the biologic activity of synthetic polypeptides consisting of repeated units of proline (Pro), glycine (Gly), and hydroxyproline (Hyp), major amino acids found within mammalian and bacterial collagens. We found that the peptides were chemoattractants for neutrophils. Moreover, their chemotactic potency was directly related to their size and composition. Thus, the pentameric peptides (Pro-Pro-Gly)5 and (Pro-Hyp-Gly)5 were more active in inducing chemotaxis than the corresponding decameric peptides (Pro-Pro-Gly)10 and (Pro-Hyp-Gly)10. In addition, the presence of Hyp in peptides reduced chemotactic activity. The synthetic peptides were also found to reduce neutrophil apoptosis. In contrast to chemotaxis, this activity was independent of peptide size or composition. The effects of the peptides on both chemotaxis and apoptosis were blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-K) and p38 mitogen-activated protein (MAP) kinase. However, only (Pro-Pro-Gly)5 and (Pro-Pro-Gly)10 induced expression of PI3-K and phosphorylation of p38 MAP kinase, suggesting a potential mechanism underlying reduced chemotactic activity of Hyp-containing peptides. Although none of the synthetic peptides tested had any effect on intracellular calcium mobilization, each induced nuclear binding activity of the transcription factor NF-κB. These findings indicate that polymeric polypeptides containing Gly-X-Y collagen-related structural motifs promote inflammation by inducing chemotaxis and blocking apoptosis. However, distinct calcium

  16. Olanzapine-induced early cardiovascular effects are mediated by the biological clock and prevented by melatonin.

    Science.gov (United States)

    Romo-Nava, Francisco; Buijs, Frederik N; Valdés-Tovar, Marcela; Benítez-King, Gloria; Basualdo, MariCarmen; Perusquía, Mercedes; Heinze, Gerhard; Escobar, Carolina; Buijs, Ruud M

    2017-05-01

    Second generation antipsychotics (SGA) are associated with adverse cardiometabolic side effects contributing to premature mortality in patients. While mechanisms mediating these cardiometabolic side effects remain poorly understood, three independent studies recently demonstrated that melatonin was protective against cardiometabolic risk in SGA-treated patients. As one of the main target areas of circulating melatonin in the brain is the suprachiasmatic nucleus (SCN), we hypothesized that the SCN is involved in SGA-induced early cardiovascular effects in Wistar rats. We evaluated the acute effects of olanzapine and melatonin in the biological clock, paraventricular nucleus and autonomic nervous system using immunohistochemistry, invasive cardiovascular measurements, and Western blot. Olanzapine induced c-Fos immunoreactivity in the SCN followed by the paraventricular nucleus and dorsal motor nucleus of the vagus indicating a potent induction of parasympathetic tone. The involvement of a SCN-parasympathetic neuronal pathway after olanzapine administration was further documented using cholera toxin-B retrograde tracing and vasoactive intestinal peptide immunohistochemistry. Olanzapine-induced decrease in blood pressure and heart rate confirmed this. Melatonin abolished olanzapine-induced SCN c-Fos immunoreactivity, including the parasympathetic pathway and cardiovascular effects while brain areas associated with olanzapine beneficial effects including the striatum, ventral tegmental area, and nucleus accumbens remained activated. In the SCN, olanzapine phosphorylated the GSK-3β, a regulator of clock activity, which melatonin prevented. Bilateral lesions of the SCN prevented the effects of olanzapine on parasympathetic activity. Collectively, results demonstrate the SCN as a key region mediating the early effects of olanzapine on cardiovascular function and show melatonin has opposing and potentially protective effects warranting additional investigation. © 2017

  17. Non-cyanobacterial diazotrophs mediate dinitrogen fixation in biological soil crusts during early crust formation.

    Science.gov (United States)

    Pepe-Ranney, Charles; Koechli, Chantal; Potrafka, Ruth; Andam, Cheryl; Eggleston, Erin; Garcia-Pichel, Ferran; Buckley, Daniel H

    2016-02-01

    Biological soil crusts (BSCs) are key components of ecosystem productivity in arid lands and they cover a substantial fraction of the terrestrial surface. In particular, BSC N2-fixation contributes significantly to the nitrogen (N) budget of arid land ecosystems. In mature crusts, N2-fixation is largely attributed to heterocystous cyanobacteria; however, early successional crusts possess few N2-fixing cyanobacteria and this suggests that microorganisms other than cyanobacteria mediate N2-fixation during the critical early stages of BSC development. DNA stable isotope probing with (15)N2 revealed that Clostridiaceae and Proteobacteria are the most common microorganisms that assimilate (15)N2 in early successional crusts. The Clostridiaceae identified are divergent from previously characterized isolates, though N2-fixation has previously been observed in this family. The Proteobacteria identified share >98.5% small subunit rRNA gene sequence identity with isolates from genera known to possess diazotrophs (for example, Pseudomonas, Klebsiella, Shigella and Ideonella). The low abundance of these heterotrophic diazotrophs in BSCs may explain why they have not been characterized previously. Diazotrophs have a critical role in BSC formation and characterization of these organisms represents a crucial step towards understanding how anthropogenic change will affect the formation and ecological function of BSCs in arid ecosystems.

  18. The dual role of microbes in corrosion

    Science.gov (United States)

    Kip, Nardy; van Veen, Johannes A

    2015-01-01

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

  19. The dual role of microbes in corrosion.

    Science.gov (United States)

    Kip, Nardy; van Veen, Johannes A

    2015-03-01

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

  20. Wet meadow ecosystems and the longevity of biologically-mediated geomorphic features

    Science.gov (United States)

    Nash, C.; Grant, G.; O'Connor, J. E.

    2016-12-01

    Upland meadows represent a ubiquitous feature of montane landscapes in the U.S. West and beyond. Characterized by flat valley floors flanked by higher-gradient hillslopes, these meadows are important features, both for the diverse ecosystems they support but also because they represent depositional features in what is primarily an erosional environment. As such, they serve as long-term chronometers of both geological and ecological processes in a portion of the landscape where such records are rare, and provide a useful microcosm for exploring many of the questions motivating critical zone science. Specifically, meadows can offer insights into questions regarding the longevity of theses biologically-mediated landscapes, and the geomorphic thresholds associated with transitions between metastable landscape states. Though categorically depositional, wet meadows have been shown to rapidly shift into erosional landscapes characterized by deep arroyos, declining water tables, and sparse, semi-arid ecosystems. Numerous hypotheses have been proposed explaining this shift: intensive ungulate usage, removal of beaver, climatic shifts, and intrinsic geomorphic evolution. Even less is known about the mechanisms controlling the construction of these meadow features. Evidence seems to suggest these channels oscillate between two metastable conditions: deeply incised, single-threaded channels and sheet-flow dominated valley-spanning wetlands. We present new evidence exploring the subsurface architecture of wet meadows and the bidirectional process cascades potentially responsible for their temporal evolution. Using a combination of near surface geophysical techniques and detailed stratigraphic descriptions of incised and un-incised meadows throughout the Silvies River Basin, OR, we examine mechanisms responsible both for the construction of these features and their apparently rapid transition from depositional to erosional. Our investigation focuses specifically on potential

  1. The dual role of microbes in corrosion

    NARCIS (Netherlands)

    Kip, D.J.; Van Veen, J.A.

    2015-01-01

    Corrosion is the result of a series of chemical, physical and (micro) biological processes leading to the deterioration of materials such as steel and stone. It is a world-wide problem with great societal and economic consequences. Current corrosion control strategies based on chemically produced

  2. Corrosion inhibitors

    International Nuclear Information System (INIS)

    El Ashry, El Sayed H.; El Nemr, Ahmed; Esawy, Sami A.; Ragab, Safaa

    2006-01-01

    The corrosion inhibition efficiencies of some triazole, oxadiazole and thiadiazole derivatives for steel in presence of acidic medium have been studied by using AM1, PM3, MINDO/3 and MNDO semi-empirical SCF molecular orbital methods. Geometric structures, total negative charge on the molecule (TNC), highest occupied molecular energy level (E HOMO ), lowest unoccupied molecular energy level (E LUMO ), core-core repulsion (CCR), dipole moment (μ) and linear solvation energy terms, molecular volume (V i ) and dipolar-polarization (π *), were correlated to corrosion inhibition efficiency. Four equations were proposed to calculate corrosion inhibition efficiency. The agreement with the experimental data was found to be satisfactory; the standard deviations between the calculated and experimental results ranged between ±0.03 and ±4.18. The inhibition efficiency was closely related to orbital energies (E HOMO and E LUMO ) and μ. The correlation between quantum parameters and experimental inhibition efficiency has been validated by single point calculations for the semi-empirical AM1 structures using B3LYP/6-31G** as a higher level of theory. The proposed equations were applied to predict the corrosion inhibition efficiency of some related structures to select molecules of possible activity from a presumable library of compounds

  3. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

    Underground pipelines transporting liquid petroleum products and natural gas are critical components of civil infrastructure, making corrosion prevention an essential part of asset-protection strategy. Underground Pipeline Corrosion provides a basic understanding of the problems associated with corrosion detection and mitigation, and of the state of the art in corrosion prevention. The topics covered in part one include: basic principles for corrosion in underground pipelines, AC-induced corrosion of underground pipelines, significance of corrosion in onshore oil and gas pipelines, n

  4. The effect of TiO2 coating on biological NiTi alloys after micro-arc oxidation treatment for corrosion resistance.

    Science.gov (United States)

    Sukuroglu, Ebru Emine; Sukuroglu, Suleyman; Akar, Kubra; Totik, Yasar; Efeoglu, Ihsan; Arslan, Ersin

    2017-08-01

    NiTi alloys exhibit good properties, such as shape memory behavior, high corrosion resistant, having the closest elasticity modulus of a human bone and superior biocompatibility properties. However, the surface problems that arise during the use of this alloy limit the usage in the industry and health sector. In recent years, micro-arc oxidation method is used to improve the surface properties and increase the usage of these alloys. In this study, the TiO 2 coatings were deposited on the NiTi substrates. The surface topography, morphology, crystallographic structure, and thickness of the coatings were determined using scanning electron microscopy and X-ray diffraction. The corrosion properties were investigated using potentiostat test unit in two different media such as NaCl solution and simulated body fluid. The results show that the coated samples have higher corrosion resistance than uncoated samples in the two different media.

  5. Mediatization

    DEFF Research Database (Denmark)

    Hjarvard, Stig

    2017-01-01

    Mediatization research shares media effects studies' ambition of answering the difficult questions with regard to whether and how media matter and influence contemporary culture and society. The two approaches nevertheless differ fundamentally in that mediatization research seeks answers...... research is concerned with long-term structural changes involving media, culture, and society, i.e. the influences of the media are understood in relation to how media are implicated in social and cultural changes and how these processes come to create new conditions for human communication and interaction....... From the perspective of mediatization research, the most important effect of the media stems from their embeddedness in culture and society....

  6. Corrosion/95 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

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

  7. Surface engineering for corrosion and wear resistance

    National Research Council Canada - National Science Library

    Davis, J. R

    2001-01-01

    ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Pitting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Crevice Corrosion . . . . . . . . ....

  8. Corrosion Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Corrosion Testing Facility is part of the Army Corrosion Office (ACO). It is a fully functional atmospheric exposure site, called the Corrosion Instrumented Test...

  9. The perlecan heparan sulfate proteoglycan mediates cellular uptake of HIV-1 Tat through a pathway responsible for biological activity

    International Nuclear Information System (INIS)

    Cell surface heparan sulfate proteoglycans (HSPGs) mediate internalization of HIV-1 Tat. Herein, we report that human WiDr cells, which express perlecan but no other HSPGs, can internalize 125 I-labeled Tat with minimal lysosomal degradation. Pre-treatment of cells with heparitinase almost completely abolished 125 I-Tat surface binding, while the use of an HIV-1 long terminal repeat (LTR) promoter-reporter construct demonstrated that transactivation was potently blocked by pretreatment of cells with heparitinase, indicating an essential role for perlecan in the biologic effects of Tat. We conclude that the perlecan mediates Tat uptake and is required for HIV-1 LTR-directed transactivation in this human cell type

  10. Copper-mediated controlled radical polymerization under biological conditions: SET-LRP in blood serum.

    Science.gov (United States)

    Zhang, Qiang; Li, Zaidong; Wilson, Paul; Haddleton, David M

    2013-07-28

    The polymerization of hydrophilic monomers is reported utilizing Cu(0)-mediated living radical polymerization, SET-LRP. Highly active Cu(0) is formed in situ as a result of rapid disproportionation of [Cu(I)(Me6-Tren)Br] in serum. Disproportionation and homogenous controlled radical polymerization (PDI 1.09-1.25) are performed for the first time in blood (sheep) serum.

  11. Palladium- and copper-mediated N-aryl bond formation reactions for the synthesis of biological active compounds

    Directory of Open Access Journals (Sweden)

    Burkhard Koenig

    2011-01-01

    Full Text Available N-Arylated aliphatic and aromatic amines are important substituents in many biologically active compounds. In the last few years, transition-metal-mediated N-aryl bond formation has become a standard procedure for the introduction of amines into aromatic systems. While N-arylation of simple aromatic halides by simple amines works with many of the described methods in high yield, the reactions may require detailed optimization if applied to the synthesis of complex molecules with additional functional groups, such as natural products or drugs. We discuss and compare in this review the three main N-arylation methods in their application to the synthesis of biologically active compounds: Palladium-catalysed Buchwald–Hartwig-type reactions, copper-mediated Ullmann-type and Chan–Lam-type N-arylation reactions. The discussed examples show that palladium-catalysed reactions are favoured for large-scale applications and tolerate sterically demanding substituents on the coupling partners better than Chan–Lam reactions. Chan–Lam N-arylations are particularly mild and do not require additional ligands, which facilitates the work-up. However, reaction times can be very long. Ullmann- and Buchwald–Hartwig-type methods have been used in intramolecular reactions, giving access to complex ring structures. All three N-arylation methods have specific advantages and disadvantages that should be considered when selecting the reaction conditions for a desired C–N bond formation in the course of a total synthesis or drug synthesis.

  12. Long-term biological effects induced by ionizing radiation--implications for dose mediated risk.

    Science.gov (United States)

    Miron, S D; Astărăstoae, V

    2014-01-01

    Ionizing radiations are considered to be risk agents that are responsible for the effects on interaction with living matter. The occurring biological effects are due to various factors such as: dose, type of radiation, exposure time, type of biological tissue, health condition and the age of the person exposed. The mechanisms involved in the direct modifications of nuclear DNA and mitochondrial DNA are reviewed. Classical target theory of energy deposition in the nucleus that causes DNA damages, in particular DNA double-strand breaks and that explanation of the biological consequences of ionizing radiation exposure is a paradigm in radiobiology. Recent experimental evidences have demonstrated the existence of a molecular mechanism that explains the non-targeted effects of ionizing radiation exposure. Among these novel data, genomic instability and a variety of bystander effects are discussed here. Those bystander effects of ionizing radiation are fulfilled by cellular communication systems that give rise to non-targeted effects in the neighboring non irradiated cells. This paper provides also a commentary on the synergistic effects induced by the co-exposures to ionizing radiation and various physical agents such as electromagnetic fields and the co-exposures to ionizing radiation and chemical environmental contaminants such as metals. The biological effects of multiple stressors on genomic instability and bystander effects are also discussed. Moreover, a brief presentation of the methods used to characterize cyto- and genotoxic damages is offered.

  13. Opuntia ficus indica peel derived pectin mediated hydroxyapatite nanoparticles: Synthesis, spectral characterization, biological and antimicrobial activities

    Science.gov (United States)

    Gopi, D.; Kanimozhi, K.; Kavitha, L.

    2015-04-01

    In the present study, we have adapted a facile and efficient green route for the synthesis of HAP nanoparticles using pectin as a template which was extracted from the peel of prickly pear (Opuntia ficus indica) fruits. The concentration of pectin plays a major role in the behavior of crystallinity, purity, morphology as well as biological property of the as-synthesized HAP nanoparticles. The extracted pectin and the as-synthesized nanoparticles were characterized by various analytical techniques. The in vitro apatite formation on the surface of the as-synthesized nanoparticles in simulated body fluid (SBF) for various days showed an enhanced bioactivity. Also, the antimicrobial activity was investigated using various microorganisms. All the results revealed the formation of pure, low crystalline and discrete granular like HAP nanoparticles of size around 25 nm with enhanced biological and antimicrobial activities. Hence the as-synthesized nanoparticles can act as a better bone regenerating material in the field of biomedicine.

  14. A Systems’ Biology Approach to Study MicroRNA-Mediated Gene Regulatory Networks

    Directory of Open Access Journals (Sweden)

    Xin Lai

    2013-01-01

    Full Text Available MicroRNAs (miRNAs are potent effectors in gene regulatory networks where aberrant miRNA expression can contribute to human diseases such as cancer. For a better understanding of the regulatory role of miRNAs in coordinating gene expression, we here present a systems biology approach combining data-driven modeling and model-driven experiments. Such an approach is characterized by an iterative process, including biological data acquisition and integration, network construction, mathematical modeling and experimental validation. To demonstrate the application of this approach, we adopt it to investigate mechanisms of collective repression on p21 by multiple miRNAs. We first construct a p21 regulatory network based on data from the literature and further expand it using algorithms that predict molecular interactions. Based on the network structure, a detailed mechanistic model is established and its parameter values are determined using data. Finally, the calibrated model is used to study the effect of different miRNA expression profiles and cooperative target regulation on p21 expression levels in different biological contexts.

  15. Biology

    Indian Academy of Sciences (India)

    I am particularly happy that the Academy is bringing out this document by Professor M S. Valiathan on Ayurvedic Biology. It is an effort to place before the scientific community, especially that of India, the unique scientific opportunities that arise out of viewing Ayurveda from the perspective of contemporary science, its tools ...

  16. Statin-associated immune-mediated myopathy: biology and clinical implications.

    Science.gov (United States)

    Christopher-Stine, Lisa; Basharat, Pari

    2017-04-01

    In the last 6 years, our understanding of statin-associated myopathy expanded to include not only a toxic myopathy with limited and reversible side-effects but also an autoimmune variety in which statins likely induce an autoimmune myopathy that is both associated with a specific autoantibody and responsive to immunosuppression and immune modulation. This review widens the reader's understanding of statin myopathy to include an autoimmune process. Statin-associated immune-mediated myopathy provides an example of an environmental trigger (statins) directly implicated in an autoimmune disease associated with a genetic predisposition as well as potential risk factors including concomitant diseases and specific statins. Given a median exposure to statins of 38 months, providers should be aware that anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase (HMGCR) myopathy may occur even after several years of statin exposure. It is important for the reader to understand the clinical presentation of statin-associated immune-mediated myopathy and the difference in its clinical presentation to that of statins as direct myotoxins. Prompt recognition of such an entity allows the clinician to immediately stop the offending agent if it has not already been discontinued as well as to recognize that statin rechallenge is not a likely option, and that prompt treatment with immunosuppression and/or immunomodulation is usually of enormous benefit to the patient in restoring muscle strength and physical function. VIDEO ABSTRACT.

  17. Corrosion/96 conference papers

    International Nuclear Information System (INIS)

    Anon.

    1996-01-01

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

  18. Antibody-Mediated Rejection in Sensitized Nonhuman Primates: Modeling Human Biology.

    Science.gov (United States)

    Burghuber, C K; Kwun, J; Page, E J; Manook, M; Gibby, A C; Leopardi, F V; Song, M; Farris, A B; Hong, J J; Villinger, F; Adams, A B; Iwakoshi, N N; Knechtle, S J

    2016-06-01

    We have established a model of sensitization in nonhuman primates and tested two immunosuppressive regimens. Animals underwent fully mismatched skin transplantation, and donor-specific antibody (DSA) response was monitored by flow cross-match. Sensitized animals subsequently underwent kidney transplantation from their skin donor. Immunosuppression included tacrolimus, mycophenolate, and methylprednisolone. Three animals received basiliximab induction; compared with nonsensitized animals, they showed a shorter mean survival time (4.7 ± 3.1 vs. 187 ± 88 days). Six animals were treated with T cell depletion (anti-CD4/CD8 mAbs), which prolonged survival (mean survival time 21.6 ± 19.0 days). All presensitized animals showed antibody-mediated rejection (AMR). In two of three basiliximab-injected animals, cellular rejection (ACR) was prominent. After T cell depletion, three of six monkeys experienced early acute rejection within 8 days with histological evidence of thrombotic microangiopathy and AMR. The remaining three monkeys survived 27-44 days, with mixed AMR and ACR. Most T cell-depleted animals experienced a rebound of DSA that correlated with deteriorating kidney function. We also found an increase in proliferating memory B cells (CD20(+) CD27(+) IgD(-) Ki67(+) ), lymph node follicular helper T cells (ICOS(+) PD-1(hi) CXCR5(+) CD4(+) ), and germinal center (GC) response. Depletion controlled cell-mediated rejection in sensitized nonhuman primates better than basiliximab, yet grafts were rejected with concomitant DSA rise. This model provides an opportunity to test novel desensitization strategies. © Copyright 2015 The American Society of Transplantation and the American Society of Transplant Surgeons.

  19. Fungus-mediated synthesis of gold nanoparticles: a novel biological approach to nanoparticle synthesis.

    Science.gov (United States)

    Honary, Soheyla; Gharaei-Fathabad, Eshrat; Barabadi, Hamed; Naghibi, Farzaneh

    2013-02-01

    The biological effects of nanoparticles and their uses as molecular probes are research areas of growing interest. The present study demonstrates an eco-friendly biosynthesis of gold nanoparticles. The pure colonies of penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii were cultured in fluid czapek dox broth. Then, their supernatants were examined for the ability to produce gold nanoparticles. In this step, 1 mM solution of AuCl added to the reaction matrixes separately. The reactions were performed in a dark environment at 28 degrees C. After 24 hours, it was observed that the color of the solutions turned to dark purple from light yellow. Synthesized gold nanoparticles were characterized by using UV-Visible Spectroscopy, Nano Zeta Sizer, Scanning Electron Microscopy and Fourier transformed infrared spectroscopy. The results showed that the gold nanoparticles were formed fairly uniform with spherical shape with the Z-average diameter of 153.3 nm, 172 nm and 160.1 nm for penicillium aurantiogriseum, penicillium citrinum, and penicillium waksmanii, respectively. The Fourier transformed infrared spectra revealed the presence of different functional groups to gold nanoparticles which were present in the fungal extract. The current approach suggests that the rapid synthesis of nanoparticles would be proper for developing a biological process for mass scale production.

  20. Identifying niche-mediated regulatory factors of stem cell phenotypic state: a systems biology approach.

    Science.gov (United States)

    Ravichandran, Srikanth; Del Sol, Antonio

    2017-02-01

    Understanding how the cellular niche controls the stem cell phenotype is often hampered due to the complexity of variegated niche composition, its dynamics, and nonlinear stem cell-niche interactions. Here, we propose a systems biology view that considers stem cell-niche interactions as a many-body problem amenable to simplification by the concept of mean field approximation. This enables approximation of the niche effect on stem cells as a constant field that induces sustained activation/inhibition of specific stem cell signaling pathways in all stem cells within heterogeneous populations exhibiting the same phenotype (niche determinants). This view offers a new basis for the development of single cell-based computational approaches for identifying niche determinants, which has potential applications in regenerative medicine and tissue engineering. © 2017 The Authors. FEBS Letters published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  1. Actinobacteria mediated synthesis of nanoparticles and their biological properties: A review.

    Science.gov (United States)

    Manivasagan, Panchanathan; Venkatesan, Jayachandran; Sivakumar, Kannan; Kim, Se-Kwon

    2016-01-01

    Nanotechnology is gaining tremendous attention in the present century due to its expected impact on many important areas such as medicine, energy, electronics, and space industries. In this context, actinobacterial biosynthesis of nanoparticles is a reliable, eco-friendly, and important aspect of green chemistry approach that interconnects microbial biotechnology and nanobiotechnology. Antibiotics produced by actinobacteria are popular in almost all the therapeutic measures and it is known that these microbes are also helpful in the biosynthesis of nanoparticles with good surface and size characteristics. In fact, actinobacteria are efficient producers of nanoparticles that show a range of biological properties, namely, antibacterial, antifungal, anticancer, anti-biofouling, anti-malarial, anti-parasitic, antioxidant, etc. This review describes the potential use of the actinobacteria as the novel sources for the biosynthesis of nanoparticles with improved biomedical applications.

  2. Rapid evolution of symbiont-mediated resistance compromises biological control of aphids by parasitoids.

    Science.gov (United States)

    Käch, Heidi; Mathé-Hubert, Hugo; Dennis, Alice B; Vorburger, Christoph

    2018-02-01

    There is growing interest in biological control as a sustainable and environmentally friendly way to control pest insects. Aphids are among the most detrimental agricultural pests worldwide, and parasitoid wasps are frequently employed for their control. The use of asexual parasitoids may improve the effectiveness of biological control because only females kill hosts and because asexual populations have a higher growth rate than sexuals. However, asexuals may have a reduced capacity to track evolutionary change in their host populations. We used a factorial experiment to compare the ability of sexual and asexual populations of the parasitoid Lysiphlebus fabarum to control caged populations of black bean aphids ( Aphis fabae ) of high and low clonal diversity. The aphids came from a natural population, and one-third of the aphid clones harbored Hamiltonella defensa , a heritable bacterial endosymbiont that increases resistance to parasitoids. We followed aphid and parasitoid population dynamics for 3 months but found no evidence that the reproductive mode of parasitoids affected their effectiveness as biocontrol agents, independent of host clonal diversity. Parasitoids failed to control aphids in most cases, because their introduction resulted in strong selection for clones protected by H. defensa . The increasingly resistant aphid populations escaped control by parasitoids, and we even observed parasitoid extinctions in many cages. The rapid evolution of symbiont-conferred resistance in turn imposed selection on parasitoids. In cages where asexual parasitoids persisted until the end of the experiment, they became dominated by a single genotype able to overcome the protection provided by H. defensa . Thus, there was evidence for parasitoid counteradaptation, but it was generally too slow for parasitoids to regain control over aphid populations. It appears that when pest aphids possess defensive symbionts, the presence of parasitoid genotypes able to overcome

  3. Extremely low frequency electromagnetic field and wound healing: implication of cytokines as biological mediators.

    Science.gov (United States)

    Pesce, Mirko; Patruno, Antonia; Speranza, Lorenza; Reale, Marcella

    2013-03-01

    Wound healing is a highly coordinated and complex process involving various cell types, chemical mediators and the surrounding extracellular matrix, resulting in a tightly orchestrated re-establishment of tissue integrity by specific cytokines. It consists of various dynamic processes including a series of overlapping phases: inflammation, proliferation, re-epithelialization and remodeling. One of the underlying mechanisms responsible for the disturbances in wound healing is an out-of-control inflammatory response that can cause pathological consequences, such as hypertrophic scars, keloids or chronic wounds and ulcers. Recently, several reports have evaluated the effects of extremely low frequency electromagnetic fields (EMFs) on tissue repair. In particular, the data analysis supports an anti-inflammatory effect of EMFs by the modulation of cytokine profiles that drive the transition from a chronic pro-inflammatory state to an anti-inflammatory state of the healing process. In this review, we focus on the effect of EMFs on skin wound healing showing emerging details of the anti-inflammatory effects of EMFs, with a view to cytokines as candidate biomarkers. Molecular clarification of the mechanisms involved in the modulation of inflammatory factors following exposure to EMFs will provide a better understanding of the cellular responses induced by EMFs and a potential, additional treatment in non-responding, chronic wounds.

  4. Evidence of market-driven size-selective fishing and the mediating effects of biological and institutional factors.

    Science.gov (United States)

    Reddy, Sheila M W; Wentz, Allison; Aburto-Oropeza, Octavio; Maxey, Martin; Nagavarapu, Sriniketh; Leslie, Heather M

    2013-06-01

    Market demand is often ignored or assumed to lead uniformly to the decline of resources. Yet little is known about how market demand influences natural resources in particular contexts, or the mediating effects of biological or institutional factors. Here, we investigate this problem by examining the Pacific red snapper (Lutjanus peru) fishery around La Paz, Mexico, where medium or "plate-sized" fish are sold to restaurants at a premium price. If higher demand for plate-sized fish increases the relative abundance of the smallest (recruit size class) and largest (most fecund) fish, this may be a market mechanism to increase stocks and fishermen's revenues. We tested this hypothesis by estimating the effect of prices on the distribution of catch across size classes using daily records of prices and catch. We linked predictions from this economic choice model to a staged-based model of the fishery to estimate the effects on the stock and revenues from harvest. We found that the supply of plate-sized fish increased by 6%, while the supply of large fish decreased by 4% as a result of a 13% price premium for plate-sized fish. This market-driven size selection increased revenues (14%) but decreased total fish biomass (-3%). However, when market-driven size selection was combined with limited institutional constraints, both fish biomass (28%) and fishermen's revenue (22%) increased. These results show that the direction and magnitude of the effects of market demand on biological populations and human behavior can depend on both biological attributes and institutional constraints. Fisheries management may capitalize on these conditional effects by implementing size-based regulations when economic and institutional incentives will enhance compliance, as in the case we describe here, or by creating compliance enhancing conditions for existing regulations.

  5. Evidence of market-driven size-selective fishing and the mediating effects of biological and institutional factors

    Science.gov (United States)

    Reddy, Sheila M. W.; Wentz, Allison; Aburto-Oropeza, Octavio; Maxey, Martin; Nagavarapu, Sriniketh; Leslie, Heather M.

    2014-01-01

    Market demand is often ignored or assumed to lead uniformly to the decline of resources. Yet little is known about how market demand influences natural resources in particular contexts, or the mediating effects of biological or institutional factors. Here, we investigate this problem by examining the Pacific red snapper (Lutjanus peru) fishery around La Paz, Mexico, where medium or “plate-sized” fish are sold to restaurants at a premium price. If higher demand for plate-sized fish increases the relative abundance of the smallest (recruit size class) and largest (most fecund) fish, this may be a market mechanism to increase stocks and fishermen’s revenues. We tested this hypothesis by estimating the effect of prices on the distribution of catch across size classes using daily records of prices and catch. We linked predictions from this economic choice model to a staged-based model of the fishery to estimate the effects on the stock and revenues from harvest. We found that the supply of plate-sized fish increased by 6%, while the supply of large fish decreased by 4% as a result of a 13% price premium for plate-sized fish. This market-driven size selection increased revenues (14%) but decreased total fish biomass (−3%). However, when market-driven size selection was combined with limited institutional constraints, both fish biomass (28%) and fishermen’s revenue (22%) increased. These results show that the direction and magnitude of the effects of market demand on biological populations and human behavior can depend on both biological attributes and institutional constraints. Fisheries management may capitalize on these conditional effects by implementing size-based regulations when economic and institutional incentives will enhance compliance, as in the case we describe here, or by creating compliance enhancing conditions for existing regulations. PMID:23865225

  6. Thermal biology mediates responses of amphibians and reptiles to habitat modification.

    Science.gov (United States)

    Nowakowski, A Justin; Watling, James I; Thompson, Michelle E; Brusch, George A; Catenazzi, Alessandro; Whitfield, Steven M; Kurz, David J; Suárez-Mayorga, Ángela; Aponte-Gutiérrez, Andrés; Donnelly, Maureen A; Todd, Brian D

    2018-03-01

    Human activities often replace native forests with warmer, modified habitats that represent novel thermal environments for biodiversity. Reducing biodiversity loss hinges upon identifying which species are most sensitive to the environmental conditions that result from habitat modification. Drawing on case studies and a meta-analysis, we examined whether observed and modelled thermal traits, including heat tolerances, variation in body temperatures, and evaporative water loss, explained variation in sensitivity of ectotherms to habitat modification. Low heat tolerances of lizards and amphibians and high evaporative water loss of amphibians were associated with increased sensitivity to habitat modification, often explaining more variation than non-thermal traits. Heat tolerances alone explained 24-66% (mean = 38%) of the variation in species responses, and these trends were largely consistent across geographic locations and spatial scales. As habitat modification alters local microclimates, the thermal biology of species will likely play a key role in the reassembly of terrestrial communities. © 2018 John Wiley & Sons Ltd/CNRS.

  7. Chemically and biologically-mediated fertilizing value of manure-derived biochar.

    Science.gov (United States)

    Subedi, R; Taupe, N; Ikoyi, I; Bertora, C; Zavattaro, L; Schmalenberger, A; Leahy, J J; Grignani, C

    2016-04-15

    This study evaluates the potential of manure-derived biochars in promoting plant growth and enhancing soil chemical and biological properties during a 150day pot experiment. Biochars from pyrolysis of poultry litter (PL) and swine manure (SM) at 400 and 600°C, and a commonly available wood chip (WC) biochar produced at high temperature (1000°C) were incorporated to silt-loam (SL) and sandy (SY) soils on a 2% dry soil weight basis. Ryegrass was sown and moisture was adjusted to 60% water filled pore space (WFPS). The PL400 and SM400 biochars significantly increased (psoil) and enhanced nitrogen (N), phosphorus (P) and potassium (K) uptake by the plants in both soils, compared to the Control. All biochars significantly increased the soil carbon (C) contents compared to the Control. Total N contents were significantly greater for PL400 and PL600 treatments in both soils. The dehydrogenase activity (DA) significantly increased for PL400 and SM400 treatments and was positively correlated with the volatile matter (VM) contents of the biochars, while β-glucosidase activity (GA) decreased for the same treatments in both soils. All biochars significantly shifted (p≤0.05) the bacterial community structure compared to the Control. This study suggests that pyrolysis of animal manures can produce a biochar that acts as both soil amendment and an organic fertilizer as proven by increased NPK uptake, positive liming effect and high soil nutrient availability, while WC biochar could work only in combination with fertilizers (organic as well as mineral). Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Catastrophes caused by corrosion

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    For many years, huge attention has been paid to the problem of corrosion damage and destruction of metallic materials. Experience shows that failures due to corrosion problems are very important, and statistics at the world level shows that the damage resulting from the effects of various forms of corrosion is substantial and that, for example, in industrialized countries it reaches 4-5% of national incomes. Significant funds are determined annually for the prevention and control of corrosion...

  9. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

    Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed.......Modelling of corrosion cracking of reinforced concrete structures is complicated as a great number of uncertain factors are involved. To get a reliable modelling a physical and mechanical understanding of the process behind corrosion in needed....

  10. Biologically-Mediated Weathering of Minerals From Nanometre Scale to Environmental Systems

    Science.gov (United States)

    Brown, D. J.; Banwart, S. A.; Smits, M. M.; Leake, J. R.; Bonneville, S.; Benning, L. G.; Haward, S. J.; Ragnarsdottir, K.

    2007-12-01

    The Weathering Science Consortium is a multi-disciplinary project that aims to create a step change in understanding how biota control mineral weathering and soil formation (http://www.wun.ac.uk/wsc). Our hypothesis is that rates of biotic weathering are driven by the energy supply from plants to the organisms, controlling their biomass, surface area of contact with minerals and their capacity to interact chemically with minerals. Symbiotic fungal mycorrhiza of 90% of plant species are empowered with an available carbohydrate supply from plants that is unparalleled amongst soil microbes. They develop extensive mycelial networks that intimately contact minerals, which they weather aggressively. We hypothesise that mycorrhiza play a critical role through their focussing of photosynthate energy from plants into sub-surface weathering environments. Our work identifies how these fungal cells, and their secretions, interact with mineral surfaces and affect the rates of nutrient transfer from minerals to the organism. Investigating these living systems allows us to create new concepts and mathematical models that can describe biological weathering and be used in computer simulations of soil weathering dynamics. We are studying these biochemical interactions at 3 levels of observation: 1. At the molecular scale to understand interactions between living cells and minerals and to quantify the chemistry that breaks down the mineral structure; 2. At the soil grain scale to quantify the activity and spatial distribution of the fungi, roots and other organisms (e.g. bacteria) and their effects on the rates at which minerals are dissolved to release nutrients; 3. At soil profile scale to test models for the spatial distribution of active fungi and carbon energy and their seasonal variability and impact on mineral dissolution rates. Here we present early results from molecular and soil grain scale experiments. We have grown pure culture (Suillus bovinus, Paxillus involutus

  11. Microbiological corrosion of metals

    International Nuclear Information System (INIS)

    Vladislavlev, V.V.

    1992-01-01

    Problems is considered of development of the microbiological corrosion of the NPP equipment. The main attention is paid to the selective character of microbiological corrosion in zones of welded joints of austenitic steels. It is noted that the presence of technological defects promotes growth of corrosional damages. Methods for microbiological corrosion protection are discussed

  12. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

    Küter, André; Geiker, Mette Rica; Møller, Per

    Reinforcement corrosion is the most important cause for deterioration of reinforced concrete structures, both with regard to costs and consequences. Thermodynamically consistent descriptions of corrosion mechanisms are expected to allow the development of innovative concepts for the management...... of reinforcement corrosion....

  13. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: a Multi-scale Computational Biological Approach

    Directory of Open Access Journals (Sweden)

    Cheryl L. Sershen

    2016-02-01

    Full Text Available In several mammalian hosts, including non-human primates, Mycobacterium tuberculosis granulomas are often hypoxic, although this has not been observed in wild type murine infection models. Mtb associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored.We develop a multi-scale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on host immune response efficacy and mycobacterial persistence. Our study integrates a model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtb's adaptation to its changing microenvironment and the qualitative infection outcome scenarios: clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through the two stages of adaptation similar to thein vitro non-replicating persistence (NRP observed in the Wayne model of Mtb dormancy. The adaptation in part contributes to the ability of Mtb to remain

  14. Oxygen Modulates the Effectiveness of Granuloma Mediated Host Response to Mycobacterium tuberculosis: A Multiscale Computational Biology Approach

    Science.gov (United States)

    Sershen, Cheryl L.; Plimpton, Steven J.; May, Elebeoba E.

    2016-01-01

    Mycobacterium tuberculosis associated granuloma formation can be viewed as a structural immune response that can contain and halt the spread of the pathogen. In several mammalian hosts, including non-human primates, Mtb granulomas are often hypoxic, although this has not been observed in wild type murine infection models. While a presumed consequence, the structural contribution of the granuloma to oxygen limitation and the concomitant impact on Mtb metabolic viability and persistence remains to be fully explored. We develop a multiscale computational model to test to what extent in vivo Mtb granulomas become hypoxic, and investigate the effects of hypoxia on host immune response efficacy and mycobacterial persistence. Our study integrates a physiological model of oxygen dynamics in the extracellular space of alveolar tissue, an agent-based model of cellular immune response, and a systems biology-based model of Mtb metabolic dynamics. Our theoretical studies suggest that the dynamics of granuloma organization mediates oxygen availability and illustrates the immunological contribution of this structural host response to infection outcome. Furthermore, our integrated model demonstrates the link between structural immune response and mechanistic drivers influencing Mtbs adaptation to its changing microenvironment and the qualitative infection outcome scenarios of clearance, containment, dissemination, and a newly observed theoretical outcome of transient containment. We observed hypoxic regions in the containment granuloma similar in size to granulomas found in mammalian in vivo models of Mtb infection. In the case of the containment outcome, our model uniquely demonstrates that immune response mediated hypoxic conditions help foster the shift down of bacteria through two stages of adaptation similar to thein vitro non-replicating persistence (NRP) observed in the Wayne model of Mtb dormancy. The adaptation in part contributes to the ability of Mtb to remain dormant

  15. Corrosion of metallic materials. Dry corrosion, aqueous corrosion and corrosion by liquid metal, methods of protection

    International Nuclear Information System (INIS)

    Helie, Max

    2015-01-01

    This book is based on a course on materials given in an engineering school. The author first gives an overview of metallurgy issues: metallic materials (pure metals, metallic alloys), defects of crystal lattices (point defects, linear defects or dislocations), equilibrium diagrams, steels and cast, thermal processing of steels, stainless steels, aluminium and its alloys, copper and its alloys. The second part addresses the properties and characterization of surfaces and interfaces: singularity of a metal surface, surface energy of a metal, energy of grain boundaries, adsorption at a material surface, metal-electrolyte interface, surface oxide-electrolyte interface, techniques of surface analysis. The third chapter addresses the electrochemical aspects of corrosion: description of the corrosion phenomenon, free enthalpy of a compound and free enthalpy of a reaction, case of dry corrosion (thermodynamic aspect, Ellingham diagram, oxidation mechanisms, experimental study, macroscopic modelling), case of aqueous corrosion (electrochemical thermodynamics and kinetics, experimental determination of corrosion rate). The fourth part addresses the different forms of aqueous corrosion: generalized corrosion (atmospheric corrosion, mechanisms and tests), localized corrosion (galvanic, pitting, cracking, intergranular, erosion and cavitation), particular cases of stress cracking (stress corrosion, fatigue-corrosion, embrittlement by hydrogen), and bi-corrosion (of non alloyed steels, of stainless steels, and of aluminium and copper alloys). The sixth chapter addresses the struggle and the protection against aqueous corrosion: methods of prevention, scope of use of main alloys, geometry-based protection of pieces, use of corrosion inhibitors, use of organic or metallic coatings, electrochemical protection. The last chapter proposes an overview of corrosion types in industrial practices: in the automotive industry, in the oil industry, in the aircraft industry, and in the

  16. Corrosion in Electronics

    DEFF Research Database (Denmark)

    Ambat, Rajan; Gudla, Helene Virginie Conseil; Verdingovas, Vadimas

    2017-01-01

    and high density packing combined with the use of several materials, which can undergo electrochemical corrosion in the presence of water film formed due to humidity exposure and bias conditions on the PCBA surface. This article provides a short review of the corrosion reliability issues of electronics due...... to the use of electronics under varying humidity conditions. Important PCBA aspects, which are fundamental to the corrosion cell formation under humid conditions, are discussed. Effect of hygroscopic residues from the process and service and their role in assisting water film build up and corrosion...... is presented. Various failure modes resulting from the corrosion and influence factors are discussed including humid and gaseous conditions....

  17. Recent advances in the chemistry and biology of anti-inflammatory and specialized pro-resolving mediators biosynthesized from n-3 docosapentaenoic acid.

    Science.gov (United States)

    Vik, Anders; Dalli, Jesmond; Hansen, Trond Vidar

    2017-06-01

    Several novel oxygenated polyunsaturated lipid mediators biosynthesized from n-3 docosapentaenoic acid were recently isolated from murine inflammatory exudates and human primary cells. These compounds belong to a distinct family of specialized pro-resolving mediators, and display potent in vivo anti-inflammatory and pro-resolution effects. The endogenously formed specialized pro-resolving mediators have attracted a great interest as lead compounds in drug discovery programs towards the development of new classes of drugs that dampen inflammation without interfering with the immune response. Detailed information on the chemical structures, cellular functions and distinct biosynthetic pathways of specialized pro-resolving lipid mediators is a central aspect of these biological actions. Herein, the isolation, structural elucidation, biosynthetic pathways, total synthesis and bioactions of the n-3 docosapentaenoic acid derived mediators PD1 n-3 DPA and MaR1 n-3 DPA are discussed. In addition, a brief discussion of a novel family of mediators derived from n-3 docosapentaenoic acid, termed 13-series resolvins is included. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments...... and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  19. SRB seawater corrosion project

    Science.gov (United States)

    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.

  20. Microbiologically Influenced Corrosion

    Science.gov (United States)

    2015-11-05

    Widdel, F. (2012) Marine sulfate-reducing bacteria cause serious corrosion of iron under electroconductive biogenic mineral crust. Envi- ronmental...inCluding oil and gas, from to 2011 [2]. Over that period of time approximately of all releases were attributed to corrosion . National ;sociati<Jn...c>fComJsicmEngineers (NACE) International [3] the cost of corrosion for onshore gas and liquid nsn1ission pipelines was $7 billion. However, there

  1. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  2. Corrosion in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

    Brondel, D. (Sedco Forex, Montrouge (France)); Edwards, R. (Schlumberger Well Services, Columbus, OH (United States)); Hayman, A. (Etudes et Productions Schlumberger, Clamart (France)); Hill, D. (Schlumberger Dowell, Tulsa, OK (United States)); Mehta, S. (Schlumberger Dowell, St. Austell (United Kingdom)); Semerad, T. (Mobil Oil Indonesia, Inc., Sumatra (Indonesia))

    1994-04-01

    Corrosion costs the oil industry billions of dollars a year, a fact that makes the role of the corrosion engineer an increasingly important one. Attention is paid to how corrosion affects every aspect of exploration and production, from offshore rigs to casing. Also the role of corrosion agents such as drilling and production fluids is reviewed. Methods of control and techniques to monitor corrosion are discussed, along with an explanation of the chemical causes of corrosion. 21 figs., 32 refs.

  3. Peer Mediated Instruction and Intervention (PMII type Classwide Peer Tutoring (CWPT and Academics Ability of Natural Science-Biology in Vocational High School

    Directory of Open Access Journals (Sweden)

    Hamsiah Hamsiah

    2014-06-01

    Full Text Available Peer Mediated Instruction and Intervention (PMII tipe Classwide Peer Tutoring (CWPTdan Kemampuan Akademik pada Pembelajaran IPA Biologi SMK Abstract: Learning science in SMK 1 Bontang still dominated by conventional learning strategy is a method of learning with lecture. This has an impact on learning outcomes of cognitive science that tends biology is still low because the students have not been trained become independent learners, thus learning innovation PMII CWPT types can be used as a breakthrough to develop the cognitive learning. This study was conducted to determine the application CWPT strategies and academic skills in science teaching vocational Biology. Quasi-experimental research with pretest-posttest design Nonequivalent Control Group. Results of the study, namely: (1 there CWPT effect on the cognitive learning, (2 no influence academic ability to cognitive learning outcomes, and (3 there is no interaction effect between learning strategy and the academic ability toward the cognitive learning. Key Words: peer-mediated instruction and intervention, classwide peer tutoring, academic skills, cognitive learning outcomes Abstrak: Pembelajaran IPA di SMKN 1 Bontang masih didominasi dengan strategi belajar konvensio-nal yaitu metode belajar dengan ceramah. Hal ini berdampak terhadap hasil belajar kognitif IPA biolo-gi yang cendrung masih rendah karena siswa belum terlatih menjadi pebelajar yang mandiri, sehingga inovasi pembelajaran PMII tipe CWPT dapat digunakan sebagai terobosan untuk mengembangkan  hasil belajar kognitif. Penelitian ini dilakukan untuk mengetahui penerapan strategi CWPT dan kemam-puan akademik pada pembelajaran IPA Biologi SMK. Penelitian eksperimen semu dengan rancangan pretest-posttest Nonequivalent Control Group. Hasil penelitian, yaitu: (1 ada pengaruh CWPT ter-hadap hasil belajar kognitif,  (2 ada  pengaruh  kemampuan akademik terhadap hasil belajar kognitif, dan (3 tidak ada  pengaruh interaksi antara

  4. Integration of Principles of Systems Biology and Radiation Biology: Toward Development of in silico Models to Optimize IUdR-Mediated Radiosensitization of DNA Mismatch Repair Deficient (Damage Tolerant) Human Cancers

    Science.gov (United States)

    Kinsella, Timothy J.; Gurkan-Cavusoglu, Evren; Du, Weinan; Loparo, Kenneth A.

    2011-01-01

    Over the last 7 years, we have focused our experimental and computational research efforts on improving our understanding of the biochemical, molecular, and cellular processing of iododeoxyuridine (IUdR) and ionizing radiation (IR) induced DNA base damage by DNA mismatch repair (MMR). These coordinated research efforts, sponsored by the National Cancer Institute Integrative Cancer Biology Program (ICBP), brought together system scientists with expertise in engineering, mathematics, and complex systems theory and translational cancer researchers with expertise in radiation biology. Our overall goal was to begin to develop computational models of IUdR- and/or IR-induced base damage processing by MMR that may provide new clinical strategies to optimize IUdR-mediated radiosensitization in MMR deficient (MMR−) “damage tolerant” human cancers. Using multiple scales of experimental testing, ranging from purified protein systems to in vitro (cellular) and to in vivo (human tumor xenografts in athymic mice) models, we have begun to integrate and interpolate these experimental data with hybrid stochastic biochemical models of MMR damage processing and probabilistic cell cycle regulation models through a systems biology approach. In this article, we highlight the results and current status of our integration of radiation biology approaches and computational modeling to enhance IUdR-mediated radiosensitization in MMR− damage tolerant cancers. PMID:22649757

  5. Integration of Principles of Systems Biology and Radiation Biology: Toward Development of in silico Models to Optimize IUdR-Mediated Radiosensitization of DNA Mismatch Repair Deficient (Damage Tolerant) Human Cancers

    International Nuclear Information System (INIS)

    Kinsella, Timothy J.; Gurkan-Cavusoglu, Evren; Du, Weinan; Loparo, Kenneth A.

    2011-01-01

    Over the last 7 years, we have focused our experimental and computational research efforts on improving our understanding of the biochemical, molecular, and cellular processing of iododeoxyuridine (IUdR) and ionizing radiation (IR) induced DNA base damage by DNA mismatch repair (MMR). These coordinated research efforts, sponsored by the National Cancer Institute Integrative Cancer Biology Program (ICBP), brought together system scientists with expertise in engineering, mathematics, and complex systems theory and translational cancer researchers with expertise in radiation biology. Our overall goal was to begin to develop computational models of IUdR- and/or IR-induced base damage processing by MMR that may provide new clinical strategies to optimize IUdR-mediated radiosensitization in MMR deficient (MMR − ) “damage tolerant” human cancers. Using multiple scales of experimental testing, ranging from purified protein systems to in vitro (cellular) and to in vivo (human tumor xenografts in athymic mice) models, we have begun to integrate and interpolate these experimental data with hybrid stochastic biochemical models of MMR damage processing and probabilistic cell cycle regulation models through a systems biology approach. In this article, we highlight the results and current status of our integration of radiation biology approaches and computational modeling to enhance IUdR-mediated radiosensitization in MMR − damage tolerant cancers.

  6. Integration of principles of systems biology and radiation biology: toward development of in silico models to optimize IUdR-mediated radiosensitization of DNA mismatch repair-deficient (damage tolerant human cancers

    Directory of Open Access Journals (Sweden)

    Timothy James Kinsella

    2011-08-01

    Full Text Available Over the last 7 years, we have focused our experimental and computational research efforts on improving our understanding of the biochemical, molecular, and cellular processing of iododeoxyuridine (IUdR and ionizing radiation (IR induced DNA base damage by DNA mismatch repair (MMR. These coordinated research efforts, sponsored by the National Cancer Institute Integrative Cancer Biology Program (ICBP, brought together system scientists with expertise in engineering, mathematics, and complex systems theory and translational cancer researchers with expertise in radiation biology. Our overall goal was to begin to develop computational models of IUdR- and/or IR- induced base damage processing by MMR that may provide new clinical strategies to optimize IUdR-mediated radiosensitiztion in MMR deficient (MMR- damage tolerant human cancers. Using multiple scales of experimental testing, ranging from purified protein systems to in vitro (cellular and to in vivo (human tumor xenografts in athymic mice models, we have begun to integrate and interpolate these experimental data with hybrid stochastic biochemical models of MMR damage processing and probabilistic cell cycle regulation models through a systems biology approach. In this article, we highlight the results and current status of our integration of radiation biology approaches and computational modeling to enhance IUdR-mediated radiosensitization in MMR- damage tolerant cancers.

  7. Nitrated type III collagen as a biological marker of nitric oxide-mediated synovial tissue metabolism in osteoarthritis

    DEFF Research Database (Denmark)

    Richardot, P; Charni-Ben Tabassi, N; Toh, L

    2009-01-01

    OBJECTIVES: Nitric oxide (NO) is a major mediator of joint tissue inflammation and damage in osteoarthritis (OA) and mediates the nitration of tyrosine (Y*) residues in proteins. We investigated the nitration of type III collagen, a major constituent of synovial membrane, in knee OA. METHODS: A p...... investigation of oxidative-related alterations of synovial tissue metabolism in OA....

  8. Biological soil crust as a bio-mediator alters hydrological processes in stabilized dune system of the Tengger Desert, China

    Science.gov (United States)

    Li, Xinrong

    2016-04-01

    Biological soil crust (BSC) is a vital component in the stabilized sand dunes with a living cover up to more than 70% of the total, which has been considered as a bio-mediator that directly influences and regulates the sand dune ecosystem processes. However, its influences on soil hydrological processes have been long neglected in Chinese deserts. In this study, BSCs of different successional stages were chose to test their influence on the hydrological processes of stabilized dune, where the groundwater deep exceeds 30m, further to explore why occur the sand-binding vegetation replacement between shrubs and herbs. Our long-term observation (60 years) shows that cyanobacteria crust has been colonized and developed after 3 years since the sand-binding vegetation has been established and dune fixation using planted xerophytic shrubs and made sand barrier (straw-checkerboard) on shifting dune surface, lichen and moss crust occurred after 20 years, and the cover of moss dominated crust could reach 70 % after 50 years. The colonization and development of BSC altered the initial soil water balance of revegetated areas by influencing rainfall infiltration, soil evaporation and dew water entrapment. The results show that BSC obviously reduced the infiltration that occurred during most rainfall events (80%), when rainfall was greater than 5 mm or less than 20 mm. The presence of BSC reduced evaporation of topsoil after small rainfall (<5 mm) because its high proportion of finer particles slowed the evaporation rate, thus keeping the water in the soil surface longer, and crust facilitated topsoil evaporation when rainfall reached 10 mm. The amount of dew entrapment increases with the succession of BSC. Moreover, the effect of the later successional BSC to dew entrapment, rainfall infiltration and evaporation was more obvious than the early successional BSC on stabilized dunes. In general, BSC reduced the amount of rainfall water that reached deeper soil (0.4-3m), which is

  9. Archaeological analogs and corrosion

    International Nuclear Information System (INIS)

    David, D.

    2008-01-01

    In the framework of the high level and long life radioactive wastes disposal deep underground, the ANDRA built a research program on the material corrosion. In particular they aim to design containers for a very long time storage. Laboratory experiments are in progress and can be completed by the analysis of metallic archaeological objects and their corrosion after hundred years. (A.L.B.)

  10. Corrosion evaluation technology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Uh Chul; Han, Jeong Ho; Nho, Kye Ho; Lee, Eun Hee; Kim, Hong Pyo; Hwang, Seong Sik; Lee, Deok Hyun; Hur, Do Haeng; Kim, Kyung Mo

    1997-09-01

    A multifrequency ACPD system was assembled which can measure very small crack. Stress corrosion cracking test system with SSRT operating high temperature was installed. Stress corrosion cracking test of newly developed alloy 600 and existing alloy 600 was carried out in steam atmosphere of 400 deg C. No crack was observed in both materials within a test period of 2,000 hrs. Corrosion fatigue test system operating at high temperature was installed in which fatigue crack was measured by CDPD. Lead enhanced the SCC of the Alloy 600 in high temperature water, had a tendency to modify a cracking morphology from intergranular to transgranular. Pit initiation preferentially occurred at Ti-rich carbide. Resistance to pit initiation decreased with increasing temperature up to 300 deg C. Test loop for erosion corrosion was designed and fabricated. Thin layer activation technique was very effective in measuring erosion corrosion. Erosion corrosion of a part of secondary side pipe was evaluated by the Check Family Codes of EPRI. Calculated values of pipe thickness by Check Family Codes coincided with the pipe thickness measured by UT with an error of {+-} 20%. Literature review on turbine failure showed that failure usually occurred in low pressure turbine rotor disc and causes of failure are stress corrosion cracking and corrosion fatigue. (author). 12 refs., 20 tabs., 77 figs.

  11. Demystifying Controlling Copper Corrosion

    Science.gov (United States)

    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. Corrosive Poisonings in Adults

    Science.gov (United States)

    Chibishev, Andon; Pereska, Zanina; Chibisheva, Vesna; Simonovska, Natasa

    2012-01-01

    Ingestion of corrosive substances may cause severe to serious injuries of the upper gastrointestinal tract and the poisoning can even result in death. Acute corrosive intoxications pose a major problem in clinical toxicology since the most commonly affected population are the young with psychic disorders, suicidal intent and alcohol addiction. The golden standard for determination of the grade and extent of the lesion is esophagogastroduodenoscopy performed in the first 12-24 hours following corrosive ingestion. The most common late complications are esophageal stenosis, gastric stenosis of the antrum and pyloris, and rarely carcinoma of the upper gastrointestinal tract. Treatment of the acute corrosive intoxications include: neutralization of corrosive agents, antibiotics, anti-secretory therapy, nutritional support, collagen synthesis inhibitors, esophageal dilation and stent placement, and surgery. PMID:23678319

  13. Effects of lentiviral RNA interference-mediated downregulation of integrin-linked kinase on biological behaviors of human lens epithelial cells

    Directory of Open Access Journals (Sweden)

    Yu-Ping Zheng

    2016-01-01

    Full Text Available AIM: To investigate the effects of lentivirus (LV mediated integrin-linked kinase (ILK RNA interference (RNAi on biological behaviors of human lens epithelial cells (LECs. METHODS: Human cataract LECs and immortalized human LEC line, human lens epithelial (HLE B-3 cells were transfected by lentiviral vector expressing ILK-specific short hairpin RNA (shRNA and then stimulated by transforming growth factor- (TGF-, the silencing of ILK gene and protein was identified by reverse transcription-polymerase chain reaction (RT-PCR and Western blot methods; biological behaviors including cell cycle and apoptosis, cell morphology, -smooth muscle actin (SMA stress fiber formation and cell migration were examined. RESULTS: Remarkable decreases of ILK protein expression were detected in LECs carrying lentiviral ILK-shRNA vector; flow cytometry revealed arresting of cell cycle progression through the G1/S transition and higher apoptosis rate in ILK-RNAi-LV transfected cells. Less -SMA stress fiber formation and migration was observed in ILK-RNAi-LV transfected LECs. CONCLUSION: The present study demonstrated that ILK was an important regulator for LECs proliferation and migration. LV mediated ILK RNAi is an effective way to decrease ILK-regulated cell growth by arresting cell cycle progression and increasing cell apoptosis, as well as, to prevent cell migration by inhibiting TGF- induced -SMA stress fiber formation. Thus, LV mediated ILK RNAi might be useful to prevent posterior capsular opacification.

  14. Corrosion Failures in Marine Environment

    OpenAIRE

    R. Krishnan

    1985-01-01

    This paper gives a brief description of typical marine environments and the most common form of corrosion of materials used in this environment. Some typical case histories of failures pertaining to pitting, bimetallic corrosion, dealloying, cavitation and stress corrosion cracking are illustrated as typical examples of corrosion failures.

  15. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

    Bech-Nielsen, Gregers; Andersen, Jens Enevold Thaulov; Reeve, John Ch

    1997-01-01

    The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell.......The chapter describes the following automated measurements: Corrosion Measurements by Titration, Imaging Corrosion by Scanning Probe Microscopy, Critical Pitting Temperature and Application of the Electrochemical Hydrogen Permeation Cell....

  16. Corrosion-resistant uranium

    Science.gov (United States)

    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.

  17. Corrosion of PWR steam generators

    International Nuclear Information System (INIS)

    Garnsey, R.

    1979-01-01

    Some designs of pressurized water reactor (PWR) steam generators have experienced a variety of corrosion problems which include stress corrosion cracking, tube thinning, pitting, fatigue, erosion-corrosion and support plate corrosion resulting in 'denting'. Large international research programmes have been mounted to investigate the phenomena. The operational experience is reviewed and mechanisms which have been proposed to explain the corrosion damage are presented. The implications for design development and for boiler and feedwater control are discussed. (author)

  18. Corrosion resistant metallic glasses for biosensing applications

    Science.gov (United States)

    Sagasti, Ariane; Lopes, Ana Catarina; Lasheras, Andoni; Palomares, Verónica; Carrizo, Javier; Gutierrez, Jon; Barandiaran, J. Manuel

    2018-04-01

    We report the fabrication by melt spinning, the magnetic and magnetoelastic characterization and corrosion behaviour study (by potentiodynamic methods) of an Fe-based, Fe-Ni-Cr-Si-B metallic glass to be used as resonant platform for biological and chemical detection purposes. The same study has been performed in Fe-Co-Si-B (with excellent magnetoelastic properties) and Fe-Ni-B (with good corrosion properties due to the substitution of Co by Ni) composition amorphous alloys. The well-known, commercial metallic glass with high corrosion resistance Metglas 2826MB®(Fe40Ni38Mo4B18), widely used for such biological and chemical detection purposes, has been also fully characterized and used as reference. For our Fe-Ni-Cr-Si-B alloy, we have measured values of magnetization (1.22 T), magnetostriction (11.5 ppm) and ΔE effect (6.8 %) values, as well as corrosion potential (-0.25 V), current density (2.54 A/m2), and polarization resistance (56.22 Ω.cm2) that make this composition very promising for the desired biosensing applications. The obtained parameters from our exhaustive characterization are compared with the values obtained for the other different composition metallic glasses and discussed in terms of Ni and Cr content.

  19. An overview of the corrosion aspect of dental implants (titanium and its alloys

    Directory of Open Access Journals (Sweden)

    Chaturvedi T

    2009-01-01

    Full Text Available Titanium and its alloys are used in dentistry for implants because of its unique combination of chemical, physical, and biological properties. They are used in dentistry in cast and wrought form. The long term presence of corrosion reaction products and ongoing corrosion lead to fractures of the alloy-abutment interface, abutment, or implant body. The combination of stress, corrosion, and bacteria contribute to implant failure. This article highlights a review of the various aspects of corrosion and biocompatibility of dental titanium implants as well as suprastructures. This knowledge will also be helpful in exploring possible research strategies for probing the biological properties of materials.

  20. Drug utilization of biological drugs in the treatment of chronic Immune-Mediated Inflammatory Diseases (IMIDs: an observational study on Italian patients

    Directory of Open Access Journals (Sweden)

    Paolo Faccendini

    2017-09-01

    Full Text Available Drug utilization of biological drugs in the treatment of chronic Immune-Mediated Inflammatory Diseases (IMIDs: an observational study on Italian patientsObjectives:The aim of this analysis was to provide an estimate of drug utilization indicators (dose escalation and dose tapering related to biologic drugs in the chronic treatment of adult patients with Immune-Mediated Inflammatory Diseases (IMIDs.Methods:We conducted an observational retrospective cohort analysis using the Policlinico di Tor Vergata (PTV database. We considered all biologic drugs dispensed by the PTV hospital pharmacy between January 2010 and December 2015:abatacept, adalimumab, certolizumab, etanercept, golimumab, infliximab (originator and biosimilar, tocilizumab, and ustekinumab were included. Drug dose escalation and dose tapering were calculated and compared with their Defined Daily Dose (DDD.Results:A total of 1803 patients with IMID and biologic drug prescription were analyzed (male: 51.2%. The majority of patients were in the class 36-50 years (n = 612. The median follow-up was 33.8 months (IQR 14.43-56.20. Dermatology was the ward with the largest number of patients (n = 882; 48.9%, followed by rheumatology (n = 619; 34.3% and gastroenterology (n = 302; 16.8%. Dose escalation was observed in 406 patients (22.5%. Infliximab biosimilar (n = 51 was the biological drug with the highest dose escalation rate (86.3%, followed by infliximab originator (n = 28; 60.3% and ustekinumab (37.8%. Etanercept was the biological drug with the lowest dose escalation rate (7.4%, followed by golimumab (12.2% and adalimumab (13.8%. In 677 patients (37.5% a dose tapering was observed. Etanercept showed the highest rate of patients with dose tapering (41.6%, followed by adalimumab (33.6%.Conclusions:The results of this analysis show that dose modification is quite common in PTV clinical practice. Considering the strong focus on the pharmaceutical expenditure and the need of cost containment

  1. BWR steel containment corrosion

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    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)

  3. Corrosion of valve metals

    International Nuclear Information System (INIS)

    Draley, J.E.

    1976-01-01

    A general survey related to the corrosion of valve metals or film-forming metals. The way these metals corrode with some general examples is described. Valve metals form relatively perfect oxide films with little breakdown or leakage when anodized

  4. Corrosion of beryllium

    International Nuclear Information System (INIS)

    Mueller, J.J.; Adolphson, D.R.

    1987-01-01

    The corrosion behavior of beryllium in aqueous and elevated-temperature oxidizing environments has been extensively studied for early-intended use of beryllium in nuclear reactors and in jet and rocket propulsion systems. Since that time, beryllium has been used as a structural material in les corrosive environments. Its primary applications include gyro systems, mirror and reentry vehicle structures, and aircraft brakes. Only a small amount of information has been published that is directly related to the evaluation of beryllium for service in the less severe or normal atmospheric environments associated with these applications. Despite the lack of published data on the corrosion of beryllium in atmospheric environments, much can be deduced about its corrosion behavior from studies of aqueous corrosion and the experiences of fabricators and users in applying, handling, processing, storing, and shipping beryllium components. The methods of corrosion protection implemented to resist water and high-temperature gaseous environments provide useful information on methods that can be applied to protect beryllium for service in future long-term structural applications

  5. Monitoring corrosion rates and localised corrosion in low conductivity water

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

    Monitoring of low corrosion rates and localised corrosion in a media with low conductivity is a challenge. In municipal district heating, quality control may be improved by implementing on-line corrosion monitoring if a suitable technique can be identified to measure both uniform and localised...... corrosion. Electrochemical techniques (LPR, EIS, crevice corrosion current) as well as direct measurement techniques (high-sensitive electrical resistance, weight loss) have been applied in operating plants. Changes in the corrosion processes are best monitored in non-aggressive, low conductivity media...

  6. Corrosion and anticorrosion. Industrial practice

    International Nuclear Information System (INIS)

    Beranger, G.; Mazille, H.

    2002-01-01

    This book comprises 14 chapters written with the collaboration of about 50 French experts of corrosion. It is complementary to another volume entitled 'corrosion of metals and alloys' and published by the same editor. This volume comprises two parts: part 1 presents the basic notions of corrosion phenomena, the properties of surfaces, the electrochemical properties of corrosion etc.. Part 2 describes the most frequent forms of corrosion encountered in industrial environments and corresponding to specific problems of protection: marine environment, atmospheric corrosion, galvanic corrosion, tribo-corrosion, stress corrosion etc.. The first 8 chapters (part 1) treat of the corrosion problems encountered in different industries and processes: oil and gas production, chemical industry, phosphoric acid industry, PWR-type power plants, corrosion of automobile vehicles, civil engineering and buildings, corrosion of biomaterials, non-destructive testing for the monitoring of corrosion. The other chapters (part 2) deal with anticorrosion and protective coatings and means: choice of materials, coatings and surface treatments, thick organic coatings and enamels, paints, corrosion inhibitors and cathodic protection. (J.S.)

  7. The role of G protein coupled receptor-mediated signaling in the biological properties of Acanthamoeba castellanii of the T4 genotype.

    Science.gov (United States)

    Aqeel, Yousuf; Siddiqui, Ruqaiyyah; Manan, Zainab; Khan, Naveed Ahmed

    2015-04-01

    Despite advances in antimicrobial chemotherapy and supportive care, the prognosis of Acanthamoeba infections remains poor, suggesting that new targets are needed that can affect parasite survival and host-pathogen interactions. G proteins and their coupled receptors are well known regulators of a variety of cellular functions. The overall aim of the present study was to study the role of G-protein coupled receptor, β adrenergic receptor on the biology and pathogenesis of keratitis isolate of Acanthamoeba castellanii of the T4 genotype. Inhibition of β adrenergic receptor using antagonist, propranolol had detrimental effects on the extracellular proteolytic activities A. castellanii as determined using zymographic assays. Conversely, β adrenergic receptor agonist, isoprenaline showed increased proteases. Interestingly, β adrenergic receptor inhibition affected A. castellanii growth (using amoebistatic assays), viability (using amoebicidal assays by measuring uptake of Trypan blue) and encystation as determined by trophozoite transformation into the cyst form. Pre-treatment of parasites with propranolol hampered A. castellanii-mediated human brain microvascular endothelial cell cytotoxicity, as measured by the lacatate dehydrogenase release. The aforementioned findings suggest that G-protein coupled receptor, β adrenergic receptor-mediated signaling in A. castellanii biology and pathogenesis may offer new pharmacological targets. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Evaluation of corrosive behavior of SAE 5155 by corrosion environment

    International Nuclear Information System (INIS)

    An, Jae Pil; Park, Keyung Dong

    2005-01-01

    In this study, the influence of shot peening and corrosive condition for corrosion property was investigated on immersed in 3.5% NaCl, 10% HNO 3 + 3% HF, 6% FeCl 3 . The immersion test was performed on two kinds of specimen. The immersion periods was performed 30days. Corrosion potential, weight loss were investigated from experimental results. From test results, the effect of shot peening on the corrosion was evaluated

  9. Low-concentration BPAF- and BPF-induced cell biological effects are mediated by ROS in MCF-7 breast cancer cells.

    Science.gov (United States)

    Lei, Bingli; Sun, Su; Xu, Jie; Feng, Chenglian; Yu, Yingxin; Xu, Gang; Wu, Minghong; Peng, Wei

    2018-02-01

    Reactive oxygen species (ROS) induced by bisphenol A (BPA) have been implicated in cellular oxidative damage and carcinogenesis. It is not known whether the potential alternatives of BPA, bisphenol AF (BPAF), and bisphenol F (BPF) can also induce ROS involved in mediating biological responses. This study evaluated the toxicity of BPAF and BPF on cell proliferation, DNA damage, intracellular calcium homeostasis, and ROS generation in MCF-7 human breast cancer cells. The results showed that BPAF at 0.001-1 μM and BPF at 0.01-1 μM significantly increased cell viability and at 25 and 50 μM, both compounds decreased cell viability. At 0.01-10 μM, both BPAF and BPF increased DNA damage and significantly elevated ROS and intracellular Ca 2+ levels in MCF-7 cells. These biological effects were attenuated by the ROS scavenger N-acetylcysteine (NAC), indicating that ROS played a key role in the observed biological effects of BPAF and BPF on MCF-7 cells. These findings can deepen our understanding on the toxicity of BPAF and BPF, and provide basis data to further evaluate the potential health harm and establish environmental standard of BPAF and BPF.

  10. A focus on polarity: Investigating the role of orientation cues in mediating student performance on mRNA synthesis tasks in an introductory cell and molecular biology course.

    Science.gov (United States)

    Olimpo, Jeffrey T; Quijas, Daniel A; Quintana, Anita M

    2017-11-01

    The central dogma has served as a foundational model for information flow, exchange, and storage in the biological sciences for several decades. Despite its continued importance, however, recent research suggests that novices in the domain possess several misconceptions regarding the aforementioned processes, including those pertaining specifically to the formation of messenger ribonucleic acid (mRNA) transcripts. In the present study, we sought to expand upon these observations through exploration of the influence of orientation cues on students' aptitude at synthesizing mRNAs from provided deoxyribonucleic acid (DNA) template strands. Data indicated that participants (n = 45) were proficient at solving tasks of this nature when the DNA template strand and the mRNA molecule were represented in an antiparallel orientation. In contrast, participants' performance decreased significantly on items in which the mRNA was depicted in a parallel orientation relative to the DNA template strand. Furthermore, participants' Grade Point Average, self-reported confidence in understanding the transcriptional process, and spatial ability were found to mediate their performance on the mRNA synthesis tasks. Collectively, these data reaffirm the need for future research and pedagogical interventions designed to enhance students' comprehension of the central dogma in a manner that makes transparent its relevance to real-world scientific phenomena. © 2017 by The International Union of Biochemistry and Molecular Biology, 45(6):501-508, 2017. © 2017 The International Union of Biochemistry and Molecular Biology.

  11. Corrosion testing facilities in India

    International Nuclear Information System (INIS)

    Viswanathan, R.; Subramanian, Venu

    1981-01-01

    Major types of corrosion tests, establishment of specifications on corrosion testing and scope of their application in practice are briefly described. Important organizations in the world which publish specifications/standards are listed. Indian organizations which undertake corrosion testing and test facilities available at them are also listed. Finally in an appendix, a comprehensive list of specifications relevant to corrosion testing is given. It is arranged under the headings: environmental testing, humidity tests, salt spray/fog tests, immersion tests, specification corrosion phenomena, (tests) with respect to special corrosion media, (tests) with respect to specific corrosion prevention methods, and specific corrosion tests using electrical and electrochemical methods (principles). Each entry in the list furnishes information about: nature of the test, standard number, and its specific application. (M.G.B.)

  12. Corrosion inhibitors for concrete bridges.

    Science.gov (United States)

    2004-12-01

    Deicing salts and salt-water spray can cause serious corrosion problems for reinforced concrete bridge structures. : These problems can lead to costly and labor-intensive repair and even replacement of the structure. Surface applied : corrosion inhib...

  13. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

    Michel, Alexander; Geiker, Mette Rica; Stang, Henrik

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold is rea......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure.......A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...

  14. Lentiviral vector-mediated genetic modification of cell substrates for the manufacture of proteins and other biologics.

    Science.gov (United States)

    Baranyi, Lajos; Roy, Andre; Embree, Heather D; Dropulic, Boro

    2010-01-01

    Transduction with Lentiviral vectors has been shown to be the most efficient method for the stable delivery of nucleic acid sequences into mammalian cells. Lentiviral vectors have been widely used in research and have recently shown success in clinical trials for human gene therapy. In this paper, we describe the use of lentiviral vectors to generate genetically modified cell substrates for the manufacture of proteins and other complex biologics. The use of lentiviral vectors for the generation of genetically modified cell substrates for the production of biologic material has several advantages over other systems: (1) highly productive mammalian cell lines can be rapidly generated without selection or gene amplification; (2) the high number of vector copies are distributed throughout the open chromatin of the genome, resulting in cell lines that are extremely stable for high levels of gene expression and, consequently, protein production; and (3) high levels of protein glycosylation are maintained despite very high levels of protein production. These advantages offer the potential to significantly improve the quality, time-to-market, and manufacturing cost of biologics for human use.

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

    Science.gov (United States)

    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. © 2013 Wiley Periodicals, Inc.

  16. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    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.

  17. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, M.; de la Fuente, D.; Díaz, I.; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morphology of steel c...

  18. Atmospheric corrosion of mild steel

    OpenAIRE

    Morcillo, Manuel; Fuente, Daniel de la; Díaz, Iván; Cano, H.

    2011-01-01

    The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a) the morpholog...

  19. Plastics for corrosion inhibition

    CERN Document Server

    Goldade, Victor A; Makarevich, Anna V; Kestelman, Vladimir N

    2005-01-01

    The development of polymer composites containing inhibitors of metal corrosion is an important endeavour in modern materials science and technology. Corrosion inhibitors can be located in a polymer matrix in the solid, liquid or gaseous phase. This book details the thermodynamic principles for selecting these components, their compatibility and their effectiveness. The various mechanisms of metal protection – barrier, inhibiting and electromechanical – are considered, as are the conflicting requirements placed on the structure of the combined material. Two main classes of inhibited materials (structural and films/coatings) are described in detail. Examples are given of structural plastics used in friction units subjected to mechano-chemical wear and of polymer films/coatings for protecting metal objects against corrosion.

  20. Accelerated cyclic corrosion tests

    Directory of Open Access Journals (Sweden)

    Prošek T.

    2016-06-01

    Full Text Available Accelerated corrosion testing is indispensable for material selection, quality control and both initial and residual life time prediction for bare and painted metallic, polymeric, adhesive and other materials in atmospheric exposure conditions. The best known Neutral Salt Spray (NSS test provides unrealistic conditions and poor correlation to exposures in atmosphere. Modern cyclic accelerated corrosion tests include intermittent salt spray, wet and dry phases and eventually other technical phases. They are able to predict the material performance in service more correctly as documented on several examples. The use of NSS should thus be restricted for quality control.

  1. Biological mediators and periodontal regeneration: a review of enamel matrix proteins at the cellular and molecular levels.

    Science.gov (United States)

    Bosshardt, Dieter D

    2008-09-01

    Despite a large body of clinical and histological data demonstrating beneficial effects of enamel matrix proteins (EMPs) for regenerative periodontal therapy, it is less clear how the available biological data can explain the mechanisms underlying the supportive effects of EMPs. To analyse all available biological data of EMPs at the cellular and molecular levels that are relevant in the context of periodontal wound healing and tissue formation. A stringent systematic approach was applied using the key words "enamel matrix proteins" OR "enamel matrix derivative" OR "emdogain" OR "amelogenin". The literature search was performed separately for epithelial cells, gingival fibroblasts, periodontal ligament cells, cementoblasts, osteogenic/chondrogenic/bone marrow cells, wound healing, and bacteria. A total of 103 papers met the inclusion criteria. EMPs affect many different cell types. Overall, the available data show that EMPs have effects on: (1) cell attachment, spreading, and chemotaxis; (2) cell proliferation and survival; (3) expression of transcription factors; (4) expression of growth factors, cytokines, extracellular matrix constituents, and other macromolecules; and (5) expression of molecules involved in the regulation of bone remodelling. All together, the data analysis provides strong evidence for EMPs to support wound healing and new periodontal tissue formation.

  2. Corrosion of bio implants

    Indian Academy of Sciences (India)

    Chemical stability, mechanical behaviour and biocompatibility in body fluids and tissues are the basic requirements for successful application of implant materials in bone fractures and replacements. Corrosion is one of the major processes affecting the life and service of orthopaedic devices made of metals and alloys used ...

  3. Corrosion resistant steel

    International Nuclear Information System (INIS)

    Zubchenko, A.S.; Borisov, V.P.; Latyshev, V.B.

    1980-01-01

    Corrosion resistant steel for production of sheets and tubes containing C, Mn, Cr, Si, Fe is suggested. It is alloyed with vanadium and cerium for improving tensile properties and ductility. The steel can be melted by a conventional method in electric-arc or induction furnaces. The mentioned steel is intended to be used as a substitute for nickel-bearing austenitic steels

  4. Corrosion in seawater systems

    International Nuclear Information System (INIS)

    Henrikson, S.

    1988-01-01

    Highly alloyed stainless steels have been exposed to natural chlorinated and chlorine-free seawater at 35 deg. C. Simulated tube-tubesheet joints, weld joints and galvanic couples with titanium, 90/10 CuNi and NiAl bronze were tested and evaluated for corrosion. The corrosion rates of various anode materials - zinc, aluminium and soft iron - were also determined. Finally the risk of hydrogen embrittlement of tubes of ferritic stainless steels and titanium as a consequence of cathodic protection was studied. An attempt was also made to explain the cracking mechanism of the ferritic steels by means of transmission electron microscopy. One important conclusion of the project is that chlorinated seawater is considerably more corrosive to stainless steels than chlorine-free water, whereas chlorination reduces the rate of galvanic corrosion of copper materials coupled to stainless steels. Hydrogen embrittlement of ferritic stainless steels and titanium as a consequence of cathodic protection of carbon steel or cast iron in the same structure can be avoided by strict potentiostatic control of the applied potential. (author)

  5. Smart Coatings for Corrosion Protection

    Science.gov (United States)

    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.

  6. Impacts of biological globalization in the Mediterranean: Unveiling the deep history of human-mediated gamebird dispersal

    Science.gov (United States)

    Forcina, Giovanni; Guerrini, Monica; van Grouw, Hein; Gupta, Brij K.; Panayides, Panicos; Hadjigerou, Pantelis; Al-Sheikhly, Omar F.; Awan, Muhammad N.; Khan, Aleem A.; Zeder, Melinda A.; Barbanera, Filippo

    2015-01-01

    Humans have a long history of moving wildlife that over time has resulted in unprecedented biotic homogenization. It is, as a result, often unclear whether certain taxa are native to a region or naturalized, and how the history of human involvement in species dispersal has shaped present-day biodiversity. Although currently an eastern Palaearctic galliform, the black francolin (Francolinus francolinus) was known to occur in the western Mediterranean from at least the time of Pliny the Elder, if not earlier. During Medieval times and the Renaissance, the black francolin was a courtly gamebird prized not only for its flavor, but also its curative, and even aphrodisiac qualities. There is uncertainty, however, whether this important gamebird was native or introduced to the region and, if the latter, what the source of introduction into the western Mediterranean was. Here we combine historical documentation with a DNA investigation of modern birds and archival (13th–20th century) specimens from across the species’ current and historically documented range. Our study proves the black francolin was nonnative to the western Mediterranean, and we document its introduction from the east via several trade routes, some reaching as far as South Asia. This finding provides insight into the reach and scope of long-distance trade routes that serviced the demand of European aristocracy for exotic species as symbols of wealth and prestige, and helps to demonstrate the lasting impact of human-mediated long-distance species dispersal on current day biodiversity. PMID:25733899

  7. Impacts of biological globalization in the Mediterranean: unveiling the deep history of human-mediated gamebird dispersal.

    Science.gov (United States)

    Forcina, Giovanni; Guerrini, Monica; van Grouw, Hein; Gupta, Brij K; Panayides, Panicos; Hadjigerou, Pantelis; Al-Sheikhly, Omar F; Awan, Muhammad N; Khan, Aleem A; Zeder, Melinda A; Barbanera, Filippo

    2015-03-17

    Humans have a long history of moving wildlife that over time has resulted in unprecedented biotic homogenization. It is, as a result, often unclear whether certain taxa are native to a region or naturalized, and how the history of human involvement in species dispersal has shaped present-day biodiversity. Although currently an eastern Palaearctic galliform, the black francolin (Francolinus francolinus) was known to occur in the western Mediterranean from at least the time of Pliny the Elder, if not earlier. During Medieval times and the Renaissance, the black francolin was a courtly gamebird prized not only for its flavor, but also its curative, and even aphrodisiac qualities. There is uncertainty, however, whether this important gamebird was native or introduced to the region and, if the latter, what the source of introduction into the western Mediterranean was. Here we combine historical documentation with a DNA investigation of modern birds and archival (13th-20th century) specimens from across the species' current and historically documented range. Our study proves the black francolin was nonnative to the western Mediterranean, and we document its introduction from the east via several trade routes, some reaching as far as South Asia. This finding provides insight into the reach and scope of long-distance trade routes that serviced the demand of European aristocracy for exotic species as symbols of wealth and prestige, and helps to demonstrate the lasting impact of human-mediated long-distance species dispersal on current day biodiversity.

  8. Mobile evaporator corrosion test results

    International Nuclear Information System (INIS)

    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 satisfactoryclose quotes (2-20 mpy) or open-quotes excellentclose 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

  9. The effect of urea on the corrosion behavior of different dental alloys.

    Science.gov (United States)

    Geckili, Onur; Bilhan, Hakan; Bilgin, Tayfun; Anthony von Fraunhofer, J

    2012-01-01

    Intraoral corrosion of dental alloys has biological, functional, and esthetic consequences. Since it is well known that the salivary urea concentrations undergo changes with various diseases, the present study was undertaken to determine the effect of salivary urea concentrations on the corrosion behavior of commonly used dental casting alloys. Three casting alloys were subjected to polarization scans in synthetic saliva with three different urea concentrations. Cyclic polarization clearly showed that urea levels above 20 mg/100 ml decreased corrosion current densities, increased the corrosion potentials and, at much higher urea levels, the breakdown potentials. The data indicate that elevated urea levels reduced the corrosion susceptibility of all alloys, possibly through adsorption of organics onto the metal surface. This study indicates that corrosion testing performed in sterile saline or synthetic saliva without organic components could be misleading.

  10. Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications

    International Nuclear Information System (INIS)

    Agarwal, Sankalp; Curtin, James; Duffy, Brendan; Jaiswal, Swarna

    2016-01-01

    Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. - Highlights: • The Mg based alloys are promising candidates for orthopaedic applications. • The rapid corrosion of Mg can affect human cells, and causes infection and implant failure. • The various physiological factors and Mg alloying elements affect the corrosion and mechanical properties of implants. • The polymeric deposit coatings enhance the corrosion resistance and biocompatibility.

  11. Electrochemical corrosion characteristics and biocompatibility of nanostructured titanium for implants

    Science.gov (United States)

    Lu, Jinwen; Zhang, Yong; Huo, Wangtu; Zhang, Wei; Zhao, Yongqing; Zhang, Yusheng

    2018-03-01

    In the present study, a nano-grained (NG) surface layer on a commercial pure (Grade-2) titanium sheet was achieved by means of sliding friction treatment. The surface characteristics, in vitro corrosion behavior and biocompatibility of NG Ti were investigated, compared with those of the conventional coarse-grained (CG) substrate. The protective passive film on NG Ti surface is thicker than that on CG Ti, leading to its enhanced biological corrosion resistance in simulated body fluid (SBF) solution. In addition, NG Ti shows a much higher hydrophilicity and nano-roughness, which is related to its significantly improved cell attachment, spreading, proliferation and maturation relative to CG Ti. The enhanced biological anti-corrosion properties and biocompatibility render NG Ti a promising biomaterial for implants.

  12. Corrosion research from the practical view - 1987

    International Nuclear Information System (INIS)

    Behrens, D.; Rahmel, A.; Baselt, J.P.

    1987-09-01

    This volume contains brief descriptions of R+D projects in corrosion research, including those just terminated, those still going on, and those due to begin soon. On the whole, the brief accounts cover 133 individual projects. The topics of the nine project groups are: Hydrogen-induced material damage; stress-cracking corrosion; fatigue cracking corrosion and local corrosion; fluid-flow-induced corrosion; high-temperature corrosion; material behaviour in waters and soils; corrosion in special media; material behaviour in seawater; corrosion protection by means of coatings and coverings; testing procedures for detecting material damage due to corrosion. (orig./MM) [de

  13. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M

    2008-06-15

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants.

  14. Corrosion Evaluation and Corrosion Control of Steam Generators

    International Nuclear Information System (INIS)

    Maeng, W. Y.; Kim, U. C.; Sung, K. W.; Na, J. W.; Lee, Y. H.; Lee, D. H.; Kim, K. M.

    2008-06-01

    Corrosion damage significantly influences the integrity and efficiency of steam generator. Corrosion problems of steam generator are unsolved issues until now even though much effort is made around world. Especially the stress corrosion cracking of heat exchange materials is the first issue to be solved. The corrosion protection method of steam generator is important and urgent for the guarantee of nuclear plant's integrity. The objectives of this study are 1) to evaluate the corrosion properties of steam generator materials, 2) to optimize the water chemistry of steam generator and 3) to develop the corrosion protection method of primary and secondary sides of steam generator. The results will be reflected to the water chemistry guideline for improving the integrity and efficiency of steam generator in domestic power plants

  15. Scanning reference electrode techniques in localized corrosion

    International Nuclear Information System (INIS)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

    The principles, advantages, and implementations of scanning reference electrode techniques are reviewed. Data related to pitting, intergranular corrosion, welds and stress corrosion cracking are presented. The technique locates the position of localized corrosion and can be used to monitor the development of corrosion and changes in the corrosion rate under a wide range of conditions

  16. Corrosion control for low-cost reliability

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This conference was held September 19-24, 1993 in Houston, Texas to provide a forum for exchange of state-of-the-art information on corrosion. Topics of interest focus on the following: atmospheric corrosion; chemical process industry corrosion; high temperature corrosion; and corrosion of plant materials. Individual papers have been processed separately for inclusion in the appropriate data bases

  17. Milestones and recent discoveries on cell death mediated by mitochondria and their interactions with biologically active amines.

    Science.gov (United States)

    Grancara, Silvia; Ohkubo, Shinji; Artico, Marco; Ciccariello, Mauro; Manente, Sabrina; Bragadin, Marcantonio; Toninello, Antonio; Agostinelli, Enzo

    2016-10-01

    Mitochondria represent cell "powerhouses," being involved in energy transduction from the electrochemical gradient to ATP synthesis. The morphology of their cell types may change, according to various metabolic processes or osmotic pressure. A new morphology of the inner membrane and mitochondrial cristae, significantly different from the previous one, has been proposed for the inner membrane and mitochondrial cristae, based on the technique of electron tomography. Mitochondrial Ca(2+) transport (the transporter has been isolated) generates reactive oxygen species and induces the mitochondrial permeability transition of both inner and outer mitochondrial membranes, leading to induction of necrosis and apoptosis. In the mitochondria of several cell types (liver, kidney, and heart), mitochondrial oxidative stress is an essential step in the induction of cell death, although not in brain, in which the phenomenon is caused by a different mechanism. Mitochondrial permeability transition drives both apoptosis and necrosis, whereas mitochondrial outer membrane permeability is characteristic of apoptosis. Adenine nucleotide translocase remains the most important component involved in membrane permeability, with the opening of the transition pore, although other proteins, such as ATP synthase or phosphate carriers, have been proposed. Intrinsic cell death is triggered by the release from mitochondria of proteic factors, such as cytochrome c, apoptosis inducing factor, and Smac/DIABLO, with the activation of caspases upon mitochondrial permeability transition or mitochondrial outer membrane permeability induction. Mitochondrial permeability transition induces the permeability of the inner membrane in sites in contact with the outer membrane; mitochondrial outer membrane permeability forms channels on the outer membrane by means of various stimuli involving Bcl-2 family proteins. The biologically active amines, spermine, and agmatine, have specific functions on mitochondria

  18. Biological phosphorus removal from abattoir wastewater at very short sludge ages mediated by novel PAO clade Comamonadaceae.

    Science.gov (United States)

    Ge, Huoqing; Batstone, Damien J; Keller, Jürg

    2015-02-01

    Recent increases in global phosphorus costs, together with the need to remove phosphorus from wastewater to comply with water discharge regulations, make phosphorus recovery from wastewater economically and environmentally attractive. Biological phosphorus (Bio-P) removal process can effectively capture the phosphorus from wastewater and concentrate it in a form that is easily amendable for recovery in contrast to traditional (chemical) phosphorus removal processes. However, Bio-P removal processes have historically been operated at medium to long solids retention times (SRTs, 10-20 days typically), which inherently increases the energy consumption while reducing the recoverable carbon fraction and hence makes it incompatible with the drive towards energy self-sufficient wastewater treatment plants. In this study, a novel high-rate Bio-P removal process has been developed as an energy efficient alternative for phosphorus removal from wastewater through operation at an SRT of less than 4 days. The process was most effective at an SRT of 2-2.5 days, achieving >90% phosphate removal. Further reducing the SRT to 1.7 days resulted in a loss of Bio-P activity. 16S pyrotag sequencing showed the community changed considerably with changes in the SRT, but that Comamonadaceae was consistently abundant when the Bio-P activity was evident. FISH analysis combined with DAPI staining confirmed that bacterial cells of Comamonadaceae arranged in tetrads contained polyphosphate, identifying them as the key polyphosphate accumulating organisms at these low SRT conditions. Overall, this paper demonstrates a novel, high-rate phosphorus removal process that can be effectively integrated with short SRT, energy-efficient carbon removal and recovery processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Conserving archaeological sites as biological and historical resources in the Gulf of Mexico: the effects of crude oil and dispersant on the biodiversity and corrosion potential of shipwreck bacterial biofilms

    Science.gov (United States)

    Salerno, J. L.; Little, B.; Lee, J.; Ray, R.; Hamdan, L. J.

    2016-02-01

    There are more than 2,000 documented shipwrecks in the Gulf of Mexico. Historic shipwrecks are invaluable cultural resources, but also serve as artificial reefs, enhancing biodiversity in the deep sea. Oil and gas-related activities have the potential to impact shipwreck sites. An estimated 30% of the oil from the Deepwater Horizon spill was deposited in the deep-sea, in areas that contain shipwrecks. We conducted field and laboratory experiments to determine if crude oil, dispersed oil, and/or dispersant affect the community composition, metabolic function, and/or corrosion potential of microorganisms inhabiting shipwrecks. Platforms containing carbon steel coupons (CSC) (n = 34 per platform) were placed at impacted and non-impacted shipwrecks or into four experimental microcosm tanks. After a 2-week acclimation period, tanks were treated with crude oil and/or dispersant or received no treatment. CSC and seawater (SW) samples for bacterial genetic analysis were collected bi-weekly (at 16 wks for field samples). Proteobacteria dominated field and lab CSC bacterial communities (77-97% of sequences). Field CSC bacterial communities differed at each wreck site (P = 0.001), with oil-impacted sites differing from control sites. Lab CSC bacterial communities differed between all treatment groups (P = 0.005) and changed over the course of the experiment (P = 0.001). CSC bacterial species richness, diversity, and dominance increased with time across all treatments indicating the recruitment and establishment of microbial biofilms on CSCs. SW bacterial communities differed between treatment groups (P = 0.001), with the dispersant treatment being most dissimilar from all other treatments (P < 0.01), and changed over time (P = 0.001). Oil- and oil/dispersant-treated CSCs exhibited higher corrosion compared to dispersant and control treatments. These findings indicate that exposure to oil and/or dispersant may alter bacterial community composition and corrosion potential.

  20. A Review on Dental Amalgam Corrosion and Its Consequences

    Directory of Open Access Journals (Sweden)

    M Fathi

    2004-02-01

    Full Text Available Dental amalgam is still the most useful restorative material for posterior teeth and has been successfully used for over a century. Dental amalgam has been widely used as a direct filling material due to its favorable mechanical properties as well as low cost and easy placement. However, the mercury it contains raises concerns about its biological toxicity and environmental hazard. Although in use for more than 150 years, dental amalgam has always been suspected more or less vigorously due to its alleged health hazard. Amalgam restorations often tarnish and corrode in oral environment. Corrosion of dental amalgam can cause galvanic action. Ion release as a result of corrosion is most important. Humans are exposed to mercury and other main dental metals via vapor or corrosion products in swallowed saliva and also direct absorption into blood from oral mucosa. During recent decades the use of dental amalgam has been discussed with respect to potential toxic effects of mercury components. In this article, the mechanisms of dental amalgam corrosion are described and results of researches are reviewed. It finally covers the corrosion of amalgams since this is the means by which metals, including mercury, can be released within oral cavity. Keywords: Dental amalgam, Amalgam corrosion, Biocompatibility, Mercury release, Amalgam restoration

  1. Purification the surface of detail from biological contaminations

    International Nuclear Information System (INIS)

    Gabdrakhmanov, Az T; Israphilov, I H; Galiakbarov, A T; Gabdrakhmanov, Al T

    2017-01-01

    More than 70% of biodegradation occur due to the corrosion processes. A biological corrosion causes the greatest damage to the oil and gas-production industry, the Navy and pipelines, constructions of water supply, means of communication. This paper proposes an effective method of purification various surfaces from biological contaminations by using of cold plasma. (paper)

  2. The Impact of Microbially Influenced Corrosion on Spent Nuclear Fuel and Storage Life

    International Nuclear Information System (INIS)

    Wolfram, J. H.; Mizia, R. E.; Jex, R.; Nelson, L.; Garcia, K. M.

    1996-01-01

    A study was performed to evaluate if microbial activity could be considered a threat to spent nuclear fuel integrity. The existing data regarding the impact of microbial influenced corrosion (MIC) on spent nuclear fuel storage does not allow a clear assessment to be made. In order to identify what further data are needed, a literature survey on MIC was accomplished with emphasis on materials used in nuclear fuel fabrication, e.g., A1, 304 SS, and zirconium. In addition, a survey was done at Savannah River, Oak Ridge, Hanford, and the INEL on the condition of their wet storage facilities. The topics discussed were the SNF path forward, the types of fuel, ramifications of damaged fuel, involvement of microbial processes, dry storage scenarios, ability to identify microbial activity, definitions of water quality, and the use of biocides. Information was also obtained at international meetings in the area of biological mediated problems in spent fuel and high level wastes. Topics dis cussed included receiving foreign reactor research fuels into existing pools, synergism between different microbes and other forms of corrosion, and cross contamination

  3. The Impact of Microbially Influenced Corrosion on Spent Nuclear Fuel and Storage Life

    Energy Technology Data Exchange (ETDEWEB)

    J. H. Wolfram; R. E. Mizia; R. Jex; L. Nelson; K. M. Garcia

    1996-10-01

    A study was performed to evaluate if microbial activity could be considered a threat to spent nuclear fuel integrity. The existing data regarding the impact of microbial influenced corrosion (MIC) on spent nuclear fuel storage does not allow a clear assessment to be made. In order to identify what further data are needed, a literature survey on MIC was accomplished with emphasis on materials used in nuclear fuel fabrication, e.g., A1, 304 SS, and zirconium. In addition, a survey was done at Savannah River, Oak Ridge, Hanford, and the INEL on the condition of their wet storage facilities. The topics discussed were the SNF path forward, the types of fuel, ramifications of damaged fuel, involvement of microbial processes, dry storage scenarios, ability to identify microbial activity, definitions of water quality, and the use of biocides. Information was also obtained at international meetings in the area of biological mediated problems in spent fuel and high level wastes. Topics dis cussed included receiving foreign reactor research fuels into existing pools, synergism between different microbes and other forms of corrosion, and cross contamination.

  4. Iron Drinking Water Pipe Corrosion Products: Concentrators of Toxic Metals

    Science.gov (United States)

    2013-01-01

    health risk. In addition Pb corrosion products may be sinks for other metals such as chromium (Cr), copper (Cu), manganese (Mn), and zinc (Zn). These...biological role of strontium’. Bone , 35, (2004): p. 583. 10. P. Watts and P. Howe: ’Strontium and Strontium Compounds’, Concise International Chemical

  5. Microbiologically Influenced Corrosion

    Science.gov (United States)

    2009-01-01

    Aliphatic amines and nitrites used as corrosion inhibitors can be degraded by microorganisms, decreasing the effectiveness of the compounds and...workers (123) reported that silicone rubber dental liners could be degraded by yeasts. Moisture and chemical resistant polymeric coatings and...to be susceptible. 7.5. Concrete. Concrete is an inert aggregate, such as rock and gravel, surrounded by a cement binder. Concrete is a moderately

  6. Corrosion Protection of Aluminum

    Science.gov (United States)

    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.

  7. Pipe Lines – External Corrosion

    Directory of Open Access Journals (Sweden)

    Dan Babor

    2008-01-01

    Full Text Available Two areas of corrosion occur in pipe lines: corrosion from the medium carried inside the pipes; corrosion attack upon the outside of the pipes (underground corrosion. Electrolytic processes are also involved in underground corrosion. Here the moisture content of the soil acts as an electrolyte, and the ions required to conduct the current are supplied by water-soluble salts (chlorides, sulfates, etc. present in the soil. The nature and amount of these soluble materials can vary within a wide range, which is seen from the varying electrical conductivity and pH (varies between 3 and 10. Therefore the characteristics of a soil will be an important factor in under-ground corrosion.

  8. Nuclear corrosion science and engineering

    CERN Document Server

    2012-01-01

    Understanding corrosion mechanisms, the systems and materials they affect, and the methods necessary for accurately measuring their incidence is of critical importance to the nuclear industry for the safe, economic and competitive running of its plants. This book reviews the fundamentals of nuclear corrosion. Corrosion of nuclear materials, i.e. the interaction between these materials and their environments, is a major issue for plant safety as well as for operation and economic competitiveness. Understanding these corrosion mechanisms, the systems and materials they affect, and the methods to accurately measure their incidence is of critical importance to the nuclear industry. Combining assessment techniques and analytical models into this understanding allows operators to predict the service life of corrosion-affected nuclear plant materials, and to apply the most appropriate maintenance and mitigation options to ensure safe long term operation. This book critically reviews the fundamental corrosion mechani...

  9. Corrosion inhibitors from expired drugs.

    Science.gov (United States)

    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%. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Corrosion of beryllium oxide

    International Nuclear Information System (INIS)

    Elston, J.; Caillat, R.

    1958-01-01

    Data are reported on the volatilization rate of beryllium oxide in moist air depending on temperature and water vapour concentration. They are concerned with powder samples or sintered shapes of various densities. For sintered samples, the volatilization rate is very low under the following conditions: - temperature: 1300 deg. C, - water vapour concentration in moist air: 25 g/m 3 , - flow rate: 12 I/hour corresponding to a speed of 40 m/hour on the surface of the sample. For calcinated powders (1300 deg. C), grain growth has been observed under a stream of moist air at 1100 deg. C. For instance, grain size changes from 0,5 to at least 2 microns after 500 hours of exposure at this temperature. Furthermore, results data are reported on corrosion of sintered beryllium oxide in pressurized water. At 250 deg. C, under a pressure of 40 kg/cm 2 water is very slightly corrosive; however, internal strains are revealed. Finally, some features on the corrosion in liquid sodium are exposed. (author) [fr

  11. Corrosion of fuel assembly materials

    International Nuclear Information System (INIS)

    Noe, M.; Frejaville, G.; Beslu, P.

    1985-08-01

    Corrosion of zircaloy-4 is reviewed in relation with previsions of improvement in PWRs performance: higher fuel burnup; increase coolant temperature, implying nucleate boiling on the hot clad surfaces; increase duration of the cycle due to load-follow operation. Actual knowledge on corrosion rates, based partly on laboratory tests, is insufficient to insure that external clad corrosion will not constitute a limitation to these improvements. Therefore, additional testing within representative conditions is felt necessary [fr

  12. Testing methodologies for corrosion fatigue

    OpenAIRE

    Delmotte, Edward; Micone, Nahuel; De Waele, Wim

    2015-01-01

    Offshore constructions are subjected to cyclic loading conditions. This situation is combined with the corrosive nature of the surrounding environment. It is of actual concern whether the combined effect is more damaging or not than the superposition of each effect independently. This literature review first introduces the reader to corrosion fatigue. Thereafter a critical comparison of some typical lab-scale fatigue corrosion test setups is given. Special emphasis is devoted to the instru...

  13. Corrosion Monitors for Embedded Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Alex L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pfeifer, Kent B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casias, Adrian L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    We have developed and characterized novel in-situ corrosion sensors to monitor and quantify the corrosive potential and history of localized environments. Embedded corrosion sensors can provide information to aid health assessments of internal electrical components including connectors, microelectronics, wires, and other susceptible parts. When combined with other data (e.g. temperature and humidity), theory, and computational simulation, the reliability of monitored systems can be predicted with higher fidelity.

  14. Corrosion problems of power engineering

    International Nuclear Information System (INIS)

    1989-01-01

    The proceedings contain 26 contributions, out of which 11 have been inputted in INIS. These are concerned with methods for the evaluation of corrosion resistance of materials for the nuclear industry, with examination of the corrosion behavior of composite overlays and of steels after the action of decontamination solutions, and with theoretical models of crack propagation. Corrosion problems of steam turbines, steam generator tubes and thermocouple bushings are discussed. (M.D.). 28 figs., 8 tabs., 63 refs

  15. Discovery and characterization of a novel lachrymatory factor synthase in Petiveria alliacea and its influence on alliinase-mediated formation of biologically active organosulfur compounds.

    Science.gov (United States)

    Musah, Rabi A; He, Quan; Kubec, Roman

    2009-11-01

    A novel lachrymatory factor synthase (LFS) was isolated and purified from the roots of the Amazonian medicinal plant Petiveria alliacea. The enzyme is a heterotetrameric glycoprotein comprised of two alpha-subunits (68.8 kD each), one gamma-subunit (22.5 kD), and one delta-subunit (11.9 kD). The two alpha-subunits are glycosylated and connected by a disulfide bridge. The LFS has an isoelectric point of 5.2. It catalyzes the formation of a sulfine lachrymator, (Z)-phenylmethanethial S-oxide, only in the presence of P. alliacea alliinase and its natural substrate, S-benzyl-l-cysteine sulfoxide (petiveriin). Depending on its concentration relative to that of P. alliacea alliinase, the LFS sequesters, to varying degrees, the sulfenic acid intermediate formed by alliinase-mediated breakdown of petiveriin. At LFS:alliinase of 5:1, LFS sequesters all of the sulfenic acid formed by alliinase action on petiveriin, and converts it entirely to (Z)-phenylmethanethial S-oxide. However, starting at LFS:alliinase of 5:2, the LFS is unable to sequester all of the sulfenic acid produced by the alliinase, with the result that sulfenic acid that escapes the action of the LFS condenses with loss of water to form S-benzyl phenylmethanethiosulfinate (petivericin). The results show that the LFS and alliinase function in tandem, with the alliinase furnishing the sulfenic acid substrate on which the LFS acts. The results also show that the LFS modulates the formation of biologically active thiosulfinates that are downstream of the alliinase in a manner dependent upon the relative concentrations of the LFS and the alliinase. These observations suggest that manipulation of LFS-to-alliinase ratios in plants displaying this system may provide a means by which to rationally modify organosulfur small molecule profiles to obtain desired flavor and/or odor signatures, or increase the presence of desirable biologically active small molecules.

  16. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

    Recently, various non-destructive and numerical methods have been used and many cases of steel corrosion are examined. For example, methods of evaluating corrosion through various numerical methods and evaluating macrocell corrosion and micro-cell corrosion using measurements have been proposed. However, there are few reports on estimating of corrosion loss with distinguishing the macro-cell and micro-cell corrosion and with resembling an actuality phenomenon. In this study, for distinguishin...

  17. Bridging cancer biology with the clinic: relative expression of a GRHL2-mediated gene-set pair predicts breast cancer metastasis.

    Directory of Open Access Journals (Sweden)

    Xinan Yang

    Full Text Available Identification and characterization of crucial gene target(s that will allow focused therapeutics development remains a challenge. We have interrogated the putative therapeutic targets associated with the transcription factor Grainy head-like 2 (GRHL2, a critical epithelial regulatory factor. We demonstrate the possibility to define the molecular functions of critical genes in terms of their personalized expression profiles, allowing appropriate functional conclusions to be derived. A novel methodology, relative expression analysis with gene-set pairs (RXA-GSP, is designed to explore the potential clinical utility of cancer-biology discovery. Observing that Grhl2-overexpression leads to increased metastatic potential in vitro, we established a model assuming Grhl2-induced or -inhibited genes confer poor or favorable prognosis respectively for cancer metastasis. Training on public gene expression profiles of 995 breast cancer patients, this method prioritized one gene-set pair (GRHL2, CDH2, FN1, CITED2, MKI67 versus CTNNB1 and CTNNA3 from all 2717 possible gene-set pairs (GSPs. The identified GSP significantly dichotomized 295 independent patients for metastasis-free survival (log-rank tested p = 0.002; severe empirical p = 0.035. It also showed evidence of clinical prognostication in another independent 388 patients collected from three studies (log-rank tested p = 3.3e-6. This GSP is independent of most traditional prognostic indicators, and is only significantly associated with the histological grade of breast cancer (p = 0.0017, a GRHL2-associated clinical character (p = 6.8e-6, Spearman correlation, suggesting that this GSP is reflective of GRHL2-mediated events. Furthermore, a literature review indicates the therapeutic potential of the identified genes. This research demonstrates a novel strategy to integrate both biological experiments and clinical gene expression profiles for extracting and elucidating the genomic

  18. Extrapolation in the development of paediatric medicines: examples from approvals for biological treatments for paediatric chronic immune-mediated inflammatory diseases.

    Science.gov (United States)

    Stefanska, Anna M; Distlerová, Dorota; Musaus, Joachim; Olski, Thorsten M; Dunder, Kristina; Salmonson, Tomas; Mentzer, Dirk; Müller-Berghaus, Jan; Hemmings, Robert; Veselý, Richard

    2017-10-01

    The European Union (EU) Paediatric Regulation requires that all new medicinal products applying for a marketing authorisation (MA) in the EU provide a paediatric investigation plan (PIP) covering a clinical and non-clinical trial programme relating to the use in the paediatric population, unless a waiver applies. Conducting trials in children is challenging on many levels, including ethical and practical issues, which may affect the availability of the clinical evidence. In scientifically justified cases, extrapolation of data from other populations can be an option to gather evidence supporting the benefit-risk assessment of the medicinal product for paediatric use. The European Medicines Agency (EMA) is working on providing a framework for extrapolation that is scientifically valid, reliable and adequate to support MA of medicines for children. It is expected that the extrapolation framework together with therapeutic area guidelines and individual case studies will support future PIPs. Extrapolation has already been employed in several paediatric development programmes including biological treatment for immune-mediated diseases. This article reviews extrapolation strategies from MA applications for products for the treatment of juvenile idiopathic arthritis, paediatric psoriasis and paediatric inflammatory bowel disease. It also provides a summary of extrapolation advice expressed in relevant EMA guidelines and initiatives supporting the use of alternative approaches in paediatric medicine development. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  19. Protease activated receptors (PARS) mediation in gyroxin biological activity; Mediacao dos receptores ativados por proteases (PARs) em atividades biologicas da giroxina

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Jose Alberto Alves da

    2009-07-01

    Gyroxin is a serine protease enzyme from the South American rattlesnake (Crotalus durissus terrificus) venom; it is only partially characterized and has multiple activities. Gyroxin induces blood coagulation, blood pressure decrease and a neurotoxic behavior named barrel rotation. The mechanisms involved in this neurotoxic activity are not known. Whereas gyroxin is a member of enzymes with high potential to become a new drug with clinical applications such as thrombin, batroxobin, ancrod, tripsyn and kalicrein, it is important to find out how gyroxin works. The analysis on agarose gel electrophoresis and circular dichroism confirmed the molecules' integrity and purity. The gyroxin intravenous administration in mice proved its neurotoxicity (barrel rotation). In vivo studies employing intravital microscopy proved that gyroxin induces vasodilation with the participation of protease activated receptors (PARs), nitric oxide and Na+K+ATPase. The leukocytes' adherence and rolling counting indicated that gyroxin has no pro inflammatory activity. Gyroxin induced platelet aggregation, which was blocked by inhibitors of PAR1 and PAR4 receptors (SCH 79797 and tcY-NH{sub 2}, respectively). Finally, it was proved that the gyroxin temporarily alter the permeability of the blood brain barrier (BBB). Our study has shown that both the protease-activated receptors and nitric oxide are mediators involved in the biological activities of gyroxin. (author)

  20. Facilities Corrosion Impacts: When Corrosion Wins, the Mission Ends

    Science.gov (United States)

    2010-02-10

    Product/Results - Technology demonstrations and implementations at DoD Installations. - Cost and performance reports. - Recommendations for design ...guidance updates– ACSIM Installation Design Standards Payoff Service life extension of aging mission critical utilities and structures. Reduction in...corrosion.  Technology- Microcapsules in the form of microscopic spheres on the order of 50 to 150 microns in diameter containing corrosion-inhibiting

  1. Archaeological analogs and corrosion; Analogues archeologiques et corrosion

    Energy Technology Data Exchange (ETDEWEB)

    David, D

    2008-07-01

    In the framework of the high level and long life radioactive wastes disposal deep underground, the ANDRA built a research program on the material corrosion. In particular they aim to design containers for a very long time storage. Laboratory experiments are in progress and can be completed by the analysis of metallic archaeological objects and their corrosion after hundred years. (A.L.B.)

  2. Phytochemicals as Green Corrosion Inhibitors in Various Corrosive ...

    African Journals Online (AJOL)

    There is an intensive effort underway to develop new plant origin corrosion inhibitors for metal subjected to various environmental conditions. These efforts have been motivated by the desire to replace toxic inhibitors used for mitigation of corrosion of various metals and alloys in aqueous solutions. Plants represent a class ...

  3. phytochemicals as green corrosion inhibitors in various corrosive ...

    African Journals Online (AJOL)

    Mgina

    with aggressive environment is one among the acceptable practices used to reduce and/or prevent corrosion. ... may exhibit electrochemical activity such as corrosion inhibition (Davis et al. 2001). Some of their results ... zinc and copper in both HCl and H2SO4 acid solutions using gravimetric and polarization measurement ...

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

    Energy Technology Data Exchange (ETDEWEB)

    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]).

  5. New technologies - new corrosion problems

    International Nuclear Information System (INIS)

    Heitz, E.

    1994-01-01

    Adequate resistance of materials to corrosion is equally important for classical and for new technologies. This article considers the economic consequences of corrosion damage and, in addition to the long-known GNP orientation, presents a new approach to the estimation of the costs of corrosion and corrosion protection via maintenance and especially corrosion-related maintenance. The significance of ''high-tech'', ''medium-tech'' and ''low-tech'' material and corrosion problems is assessed. Selected examples taken from new technologies in the areas of power engineering, environmental engineering, chemical engineering, and biotechnology demonstrate the great significance of the problems. It is concluded that corrosion research and corrosion prevention technology will never come to an end but will constantly face new problems. Two technologies are of particular interest since they focus attention on new methods of investigation: microelectronics and final disposal of radioactive wastes. The article closes by considering the importance of the transfer of experience and technology. Since the manufacturs and operators of machines and plant do not generally have access to the very latest knowledge, they should be kept informed through advisory services, experimental studies, databases, and further education. (orig.) [de

  6. corrosion inhibitor for carbon steels

    African Journals Online (AJOL)

    potentiodynamic polarisation techniques. It was found that. CNSL reduces the extent of the electrochemical processes taking place on carbon steel undergoing corrosion. The corrosion rate of the carbon steel was reduced by over 92 % when only 300 ppm of CNSL was applied. This indicates that. CNSL is a potential ...

  7. Tensammetric Studies on Corrosion Inhibitors

    Indian Academy of Sciences (India)

    Tensammetric Studies on Corrosion Inhibitors-I 277 paralleled potential data and corrosion data given in the next section. The only chemicals which bring about increased polarization of the steel speci- mens are sodium nitrite, dicyclohexylamine nitrite, cyclohexylamine and morpholine. The extent of polarization follows the ...

  8. Agricultural Polymers as Corrosion Inhibitors

    Science.gov (United States)

    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...

  9. DPC materials and corrosion environments.

    Energy Technology Data Exchange (ETDEWEB)

    Ilgen, Anastasia Gennadyevna; Bryan, Charles R.; Teich-McGoldrick, Stephanie; Hardin, Ernest

    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.

  10. Corrosion of Ceramic Materials

    Science.gov (United States)

    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.

  11. Electrochemical studies of corrosion inhibitors

    Science.gov (United States)

    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.

  12. Fatigue and Corrosion in Metals

    CERN Document Server

    Milella, Pietro Paolo

    2013-01-01

    This textbook, suitable for students, researchers and engineers, gathers the experience of more than 20 years of teaching fracture mechanics, fatigue and corrosion to professional engineers and running experimental tests and verifications to solve practical problems in engineering applications. As such, it is a comprehensive blend of fundamental knowledge and technical tools to address the issues of fatigue and corrosion. The book initiates with a systematic description of fatigue from a phenomenological point of view, since the early signs of submicroscopic damage in few surface grains and continues describing, step by step, how these precursors develop to become mechanically small cracks and, eventually, macrocracks whose growth is governed by fracture mechanics. But fracture mechanics is also introduced to analyze stress corrosion and corrosion assisted fatigue in a rather advanced fashion. The author dedicates a particular attention to corrosion starting with an electrochemical treatment that mechanical e...

  13. Biological adhesion of the flatworm Macrostomum lignano relies on a duo-gland system and is mediated by a cell type-specific intermediate filament protein.

    Science.gov (United States)

    Lengerer, Birgit; Pjeta, Robert; Wunderer, Julia; Rodrigues, Marcelo; Arbore, Roberto; Schärer, Lukas; Berezikov, Eugene; Hess, Michael W; Pfaller, Kristian; Egger, Bernhard; Obwegeser, Sabrina; Salvenmoser, Willi; Ladurner, Peter

    2014-02-12

    Free-living flatworms, in both marine and freshwater environments, are able to adhere to and release from a substrate several times within a second. This reversible adhesion relies on adhesive organs comprised of three cell types: an adhesive gland cell, a releasing gland cell, and an anchor cell, which is a modified epidermal cell responsible for structural support. However, nothing is currently known about the molecules that are involved in this adhesion process. In this study we present the detailed morphology of the adhesive organs of the free-living marine flatworm Macrostomum lignano. About 130 adhesive organs are located in a horse-shoe-shaped arc along the ventral side of the tail plate. Each organ consists of exactly three cells, an adhesive gland cell, a releasing gland cell, and an anchor cell. The necks of the two gland cells penetrate the anchor cell through a common pore. Modified microvilli of the anchor cell form a collar surrounding the necks of the adhesive- and releasing glands, jointly forming the papilla, the outer visible part of the adhesive organs. Next, we identified an intermediate filament (IF) gene, macif1, which is expressed in the anchor cells. RNA interference mediated knock-down resulted in the first experimentally induced non-adhesion phenotype in any marine animal. Specifically, the absence of intermediate filaments in the anchor cells led to papillae with open tips, a reduction of the cytoskeleton network, a decline in hemidesmosomal connections, and to shortened microvilli containing less actin. Our findings reveal an elaborate biological adhesion system in a free-living flatworm, which permits impressively rapid temporary adhesion-release performance in the marine environment. We demonstrate that the structural integrity of the supportive cell, the anchor cell, is essential for this adhesion process: the knock-down of the anchor cell-specific intermediate filament gene resulted in the inability of the animals to adhere. The RNAi

  14. Corrosion behavior of stainless steel weldments in physiological solutions

    Science.gov (United States)

    Farooq, A.; Azam, M.; Deen, K. M.

    2018-01-01

    In this study corrosion behavior of TIG welded 316L stainless steel plates in simulated biological solutions is investigated. The mechanical testing results showed slight decrease in ductility after welding and the fracture surface represented mixed cleavage and inclusions containing dimple structure. The heat affected and weld zone (WZ) demonstrated higher corrosion potential and relatively large pitting tendency than base metal (BM) in both Hank’s and Ringer’s solution. The formation of delta (δ) ferrite in the heat affected and WZ decreased the corrosion resistance as confirmed from potentiodynamic Tafel scans. The decrease in pitting resistance and lower protection tendency of the WZ compared to BM and heat affected zone was also quantified from the cyclic polarization trends.

  15. IN DRIFT CORROSION PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    D.M. Jolley

    1999-12-02

    As directed by a written development plan (CRWMS M&O 1999a), a conceptual model for steel and corrosion products in the engineered barrier system (EBS) is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE) Revision 2 (NRC 1999). This document provides the conceptual framework for the in-drift corrosion products sub-model to be used in subsequent PAO analyses including the EBS physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. However, the concepts discussed within this report may also apply to some near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts.

  16. Discovery of innovative therapies for rare immune-mediated inflammatory diseases via off-label prescription of biologics: the case of IL-6 receptor blockade in Castleman’s disease

    Directory of Open Access Journals (Sweden)

    Anne eMusters

    2015-12-01

    Full Text Available Biologics have revolutionized the field of clinical immunology and proven to be both effective and safe in common immune-mediated inflammatory diseases (IMIDs such as rheumatoid arthritis, inflammatory bowel diseases, and various haematological disorders. However, in patients with rare, severe IMIDs failing on standard therapies it is virtually impossible to conduct randomized controlled trials. Therefore, biologics are usually prescribed off-label in these often severely ill patients. Unfortunately, off-label prescription is sometimes hampered in these diseases due to a lack of reimbursement that is often based on a presumed lack of evidence for effectiveness. In the present article will discuss that off-label prescription of biologics can be a good way to discover new treatments for rare diseases. This will be ilustrated using a case of multicentric Castleman’s disease, an immune-mediated lymphoproliferative disorder, in which off-label tocilizumab (humanized anti-IL-6 receptor blocking antibody treatment resulted in remarkable clinical improvement. Furthermore, we will give recommendations for monitoring efficacy and safety of biologic treatment in rare IMIDs, including the use of registries. In conclusion, we put forward that innovative treatments for rare IMIDs can be discovered via off-label prescription of biologicals, provided that this is based on rational arguments including knowledge of the pathophysiology of the disease.

  17. Improvement of PWR reliability by corrosion prevention

    International Nuclear Information System (INIS)

    Takamatsu, Hiroshi

    1999-01-01

    Since first PWR in Japan started commercial operation in 1970, we have encountered the various modes of corrosion on primary and secondary side components. We have paid much efforts for resolving these corrosion problems, that is, investigating the causes of corrosion and establishing the countermeasures for these corrosion. We summarize these efforts in this article. (author)

  18. Corrosion detection of nanowires by magnetic sensors

    KAUST Repository

    Kosel, Jürgen

    2017-10-05

    Disclosed are various embodiments related to a corrosion detection device for detecting corrosive environments. A corrosion detection device comprises a magnetic sensor and at least one magnetic nanowire disposed on the magnetic sensor. The magnetic sensor is configured to detect corrosion of the one or more magnetic nanowires based at least in part on a magnetic field of the one or more magnetic nanowires.

  19. Recognition and Analysis of Corrosion Failure Mechanisms

    Directory of Open Access Journals (Sweden)

    Steven Suess

    2006-02-01

    Full Text Available Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, material evaluation, data review and conclusion procurement. In analyzing corrosion failures, one must recognize the wide range of common corrosion mechanisms. The features of any corrosion failure give strong clues as to the most likely cause of the corrosion. This article details a proven approach to properly determining the root cause of a failure, and includes pictographic illustrations of the most common corrosion mechanisms, including general corrosion, pitting, galvanic corrosion, dealloying, crevice corrosion, microbiologically-influenced corrosion (MIC, corrosion fatigue, stress corrosion cracking (SCC, intergranular corrosion, fretting, erosion corrosion and hydrogen damage.

  20. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott t.

    2011-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of existing microcapsulation designs, the corrosion controlled release function that triggers the delivery of corrosion indicators and inhibitors on demand, only when and where needed. Microencapsulation of self-healing agents for autonomous repair of mechanical damage to the coating is also being pursued. Corrosion indicators, corrosion inhibitors, as well as self-healing agents, have been encapsulated and dispersed into several paint systems to test the corrosion detection, inhibition, and self-healing properties of the coating. Key words: Corrosion, coating, autonomous corrosion control, corrosion indication, corrosion inhibition, self-healing coating, smart coating, multifunctional coating, microencapsulation.

  1. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and ...

  2. Atmospheric corrosion of mild steel

    Directory of Open Access Journals (Sweden)

    Morcillo, M.

    2011-10-01

    Full Text Available The atmospheric corrosion of mild steel is an extensive topic that has been studied by many authors in different regions throughout the world. This compilation paper incorporates relevant publications on the subject, in particular about the nature of atmospheric corrosion products, mechanisms of atmospheric corrosion and kinetics of the atmospheric corrosion process, paying special attention to two matters upon which relatively less information has been published: a the morphology of steel corrosion products and corrosion product layers; and b long-term atmospheric corrosion ( > 10 years.

    La corrosión atmosférica del acero suave es un tema de gran amplitud que ha sido tratado por muchos autores en numerosas regiones del mundo. Este artículo de compilación incorpora publicaciones relevantes sobre esta temática, en particular sobre la naturaleza de los productos de corrosión atmosférica, mecanismos y cinética de los procesos de corrosión atmosférica, prestando una atención especial a dos aspectos sobre los que la información publicada ha sido menos abundante: a morfología de los productos de corrosión del acero y capas de productos de corrosión, y b corrosión atmosférica a larga duración (> 10 años.

  3. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

    This book covers the use of nanomaterials to prevent corrosion. The first section deals with the fundamentals of corrosion prevention using nanomaterials. Part two includes a series of case studies and applications of nanomaterials for corrosion control.$bCorrosion is an expensive and potentially dangerous problem in many industries. The potential application of different nanostructured materials in corrosion protection, prevention and control is a subject of increasing interest. Corrosion protection and control using nanomaterials explores the potential use of nanotechnology in corrosion control. The book is divided into two parts. Part one looks at the fundamentals of corrosion behaviour and the manufacture of nanocrystalline materials. Chapters discuss the impact of nanotechnology in reducing corrosion cost, and investigate the influence of various factors including thermodynamics, kinetics and grain size on the corrosion behaviour of nanocrystalline materials. There are also chapters on electrodeposition ...

  4. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  5. Corrosion aspects in reprocessing technology

    International Nuclear Information System (INIS)

    Fauvet, P.; Pinard Legry, G.

    1992-01-01

    This paper presents two examples illustrating the importance of the physicochemical conditions existing at the metal-medium interface on the corrosion behaviour of materials utilized in spent fuel reprocessing plants: corrosion of a stainless steel in the presence of nitric acid condensates, which is much more severe than in the liquid bulk; behaviour of zirconium, which has an outstanding corrosion resistance in nitric acid, but may suffer depassivation in drastic conditions (not existing in reprocessing plants), with the consequence of a loss of the protective effect of the zirconia passive layer

  6. Cracking and corrosion recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

    Suik, H. [Tallinn Technical University, Horizon Pulp and Paper, Tallinn (Estonia)

    1998-12-31

    The corrosion of heat surfaces and the cracking the drums are the main problems of the recovery boiler. These phenomena have been appeared during long-term operation of boiler `Mitsubishi - 315` erected at 1964. Depth of the crack is depending on the number of shutdowns and on operation time. Corrosion intensity of different heat surfaces is varying depend on the metal temperature and the conditions at place of positioning of tube. The lowest intensity of corrosion is on the bank tubes and the greatest is on the tubes of the second stage superheater and on the tubes at the openings of air ports. (orig.) 5 refs.

  7. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

    Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

  8. Corrosion and corrosion fatigue of airframe aluminum alloys

    Science.gov (United States)

    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.

  9. Assessing resistance of stabilized corrosion resistant steels to intergranular corrosion

    International Nuclear Information System (INIS)

    Karas, A.; Cihal, V. Jr.; Vanek, V.; Herzan, J.; Protiva, K.; Cihal, V.

    1987-01-01

    Resistance to intergranular corrosion was determined for four types of titanium-stabilized steels from the coefficients of stabilization efficiency according to the degree the chemical composition was known. The ATA SUPER steel showed the highest resistance parameter value. The resistance of this type of steel of a specific composition, showing a relatively low value of mean nitrogen content was compared with steel of an optimized chemical composition and with low-carbon niobium stabilized, molybdenum modified steels. The comparison showed guarantees of a sufficient resistance of the steel to intergranular corrosion. The method of assessing the resistance to intergranular corrosion using the calculation of the minimum content of Cr', i.e., the effective chromium content, and the maximum effective carbon content C' giving the resistance parameter k seems to be prospective for practical use in the production of corrosion resistant steels. (author). 1 tab., 5 figs., 15 refs

  10. The issue of corrosion in dental implants: a review.

    Science.gov (United States)

    Olmedo, Daniel G; Tasat, Déborah R; Duffó, Gustavo; Guglielmotti, Maria B; Cabrini, Rómulo L

    2009-01-01

    Pure titanium or titanium alloys, and to a lesser extent, zirconium, are metals that are often used in direct contact with host tissues. These metallic biomaterials are highly reactive, and on exposure to fluid media or air, quickly develop a layer of titanium dioxide (TiO2) or zirconium dioxide (ZrO2). This layer of dioxide forms a boundary at the interface between the biological medium and the metal structure, determining the degree of biocompatibility and the biological response of the implant. Corrosion is the deterioration a metal undergoes as a result of the surrounding medium (electrochemical attack), which causes the release of ions into the microenvironment. No metal or alloy is entirely inert in vivo. Corrosion phenomena at the interlace are particularly important in the evolution of both dental and orthopedic implants and one of the possible causes of implant failure after initial success. This paper comprises a review of literature and presents results of our laboratory experiments related to the study of corrosion, with special emphasis on dental implants. In situ degradation of a metallic implant is undesirable because it alters the structural integrity of the implant. The issue of corrosion is not limited to a local problem because the particles pmduced as a result could migrate to distant sites, whose evolution would require further studies.

  11. Corrosion resistant ceramic materials

    Science.gov (United States)

    Kaun, Thomas D.

    1996-01-01

    Ceramic materials which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200.degree.-550.degree. C. or organic salt (including SO.sub.2 and SO.sub.2 Cl.sub.2) at temperatures of 25.degree.-200.degree. C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components.

  12. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process of...... techniques like electrical resistance or mass loss should be used instead.......Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process...... if the biofilm in combination with ferrous sulfide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 with electrochemical techniques - both by linear polarization resistance (LPR) and electrochemicel impedance spectroscopy (EIS). Oxygen entering the system...

  13. Greener Approach towards Corrosion Inhibition

    Directory of Open Access Journals (Sweden)

    Neha Patni

    2013-01-01

    Full Text Available Corrosion control of metals is technically, economically, environmentally, and aesthetically important. The best option is to use inhibitors for protecting metals and alloys against corrosion. As organic corrosion inhibitors are toxic in nature, so green inhibitors which are biodegradable, without any heavy metals and other toxic compounds, are promoted. Also plant products are inexpensive, renewable, and readily available. Tannins, organic amino acids, alkaloids, and organic dyes of plant origin have good corrosion-inhibiting abilities. Plant extracts contain many organic compounds, having polar atoms such as O, P, S, and N. These are adsorbed on the metal surface by these polar atoms, and protective films are formed, and various adsorption isotherms are obeyed. Various types of green inhibitors and their effect on different metals are mentioned in the paper.

  14. Study of corrosion rate and deposit accumulation under circulating water concentration in industrial applications

    OpenAIRE

    Чиченин, Вадим Валентинович; Кишневский, Виктор Афанасьевич; Грицаенко, Анастасия Сергеевна; Савич, Святослав Лаврентьевич; Шуляк, Ирина Дмитриевна

    2015-01-01

    The methods of investigating and the results of testing the corrosion rate and deposit accumulation on control samples of various metals in two similar industrial circulating cooling systems (CCS) with specified water chemistry were presented. As the make-up water, biologically treated municipal and industrial wastewater with a high content of anions of strong acids were used in systems.The results of the influence of phosphate inhibitors on the processes of deposit accumulation and corrosion...

  15. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

    Choi, Jor-Shan [El Cerrito, CA; Farmer, Joseph C [Tracy, CA; Lee, Chuck K [Hayward, CA; Walker, Jeffrey [Gaithersburg, MD; Russell, Paige [Las Vegas, NV; Kirkwood, Jon [Saint Leonard, MD; Yang, Nancy [Lafayette, CA; Champagne, Victor [Oxford, PA

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  16. Corrosion-Resistant Acrylic Coatings

    Science.gov (United States)

    1992-03-31

    ester solvents include ethylene glycol acceptable for anti-corrosive compositions. Blistering in monoethyl ether acetate, diethylene glycol monoethyl ...corrosion and 0 is i inch or more methyl isobutyl ketone. diethyl ketone, and cyclohexa- creepage from the scribe. Ratings of 3 or above are none. Glycol ...45 * coating is determined in accordance with ASTM ether acetate, etc. D714-56. This method describes blister size as numbers The coating has

  17. Environmentally Friendly Corrosion Preventative Compounds

    Science.gov (United States)

    Calle, Luz Marina; Montgomery, Eliza; Kolody, Mark; Curran, Jerry; Back, Teddy; Balles, Angela

    2012-01-01

    The objective of the Ground Systems Development and Operations Program Environmentally Friendly Corrosion Protective Coatings and Corrosion Preventive Compounds (CPCs) project is to identify, test, and develop qualification criteria for the use of environmentally friendly corrosion protective coatings and CPCs for flight hardware and ground support equipment. This document is the Final Report for Phase I evaluations, which included physical property, corrosion resistance, and NASA spaceport environment compatibility testing and analysis of fifteen CPC types. The CPCs consisted of ten different oily film CPCs and five different wax or grease CPC types. Physical property testing encompassed measuring various properties of the bulk CPCs, while corrosion resistance testing directly measured the ability of each CPC material to protect various metals against corrosion. The NASA spaceport environment compatibility testing included common tests required by NASA-STD-6001, "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion". At the end of Phase I, CPC materials were down-selected for inclusion in the next test phases. This final report includes all data and analysis of results obtained by following the experimental test plan that was developed as part of the project. Highlights of the results are summarized by test criteria type.

  18. Corrosion testing in flash tanks

    Energy Technology Data Exchange (ETDEWEB)

    Clarke, S.J.; Stead, N.J.

    1999-07-01

    As kraft pulp mills adopt modified cooking processes, an increasing amount of corrosion of carbon steel digester systems is being encountered. Many mills have had severe corrosion in the flash tanks, in particular, the first ({number{underscore}sign}1) flash tank. The work described in this report was aimed at characterizing the corrosion. Coupons of carbon steel, several stainless steels and titanium were exposed at two mills. At mill A, identical sets of coupons were exposed in the {number{underscore}sign}1 and {number{underscore}sign}2 flash tank. At mill B, three identical sets of coupons were placed in flash tank {number{underscore}sign}1. The results of the exposures showed that both carbon steel and titanium suffered high rates of general corrosion, while the stainless steels suffered varying degrees of localized attack. The ranking of the resistance of corrosion in the flash tank was the same ranking as would be expected in a reducing acid environment. In the light of the coupon results, organic acids is concluded to be the most likely cause of corrosion of the flash tanks.

  19. Testing of Biologically Inhibiting Surface

    DEFF Research Database (Denmark)

    Bill Madsen, Thomas; Larsen, Erup

    2003-01-01

    The main purpose of this course is to examine a newly developed biologically inhibiting material with regards to galvanic corrosion and electrochemical properties. More in detail, the concern was how the material would react when exposed to cleaning agents, here under CIP cleaning (Cleaning...

  20. Encyclopedia of electrochemistry. Vol. 4. Corrosion and oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Stratmann, M. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany); Frankel, G.S. (eds.) [Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    2003-07-01

    This book is one of the eleven volumes of the ''Encyclopaedia of Electrochemistry'' and provides both an introduction to the different fields of corrosion as well as a detailed overview of the subjects. The volume is divided into seven main chapters each of them containing some special papers written by well known specialists. The main chapters are structured as follows: 1. Fundamentals (of corrosion, thermodynamics, kinetics and transport phenomena in electrolytic corrosion); 2. Homogeneous corrosion of metallic materials in electrolytes; 3. Corrosion of oxide covered materials (Atmospheric corrosion; Passivity of metals, alloys, and semiconductors); 4. Localised corrosion phenomena (Crevice corrosion; Pitting corrosion; Intergranular corrosion); 5. Corrosion protection 6. Corrosion in special environments (Molten salt-induced corrosion of metals; High-temperature corrosion of metals by gases; Microbiologically influenced corrosion); and 7. Electrochemical techniques for corrosion.

  1. A Theoretical Model for Metal Corrosion Degradation

    Directory of Open Access Journals (Sweden)

    David V. Svintradze

    2010-01-01

    Full Text Available Many aluminum and stainless steel alloys contain thin oxide layers on the metal surface which greatly reduce the corrosion rate. Pitting corrosion, a result of localized breakdown of such films, results in accelerated dissolution of the underlying metal through pits. Many researchers have studied pitting corrosion for several decades and the exact governing equation for corrosion pit degradation has not been obtained. In this study, the governing equation for corrosion degradation due to pitting corrosion behavior was derived from solid-state physics and some solutions and simulations are presented and discussed.

  2. Solutions of corrosion Problems in advanced Technologies

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Karlsson, Asger

    1999-01-01

    were investigated using light optical and scanning electron microscopy. The ferritic steels suffered from corrosion mainly via material loss. The austenitic steels suffered from predominantly selective corrosion resulting in chromium depletion from the alloy. A clear trend was observed that selective...... corrosion increased with increasing chromium content of the alloy.......Austenitic and ferritic steels were exposed in the superheater area of a straw-fired CHP plant. The specimens were exposed for 1400 hours at 450-600°C. The rate of corrosion was assessed based on unattacked metal remaining. The corrosion products and course of corrosion for the various steel types...

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

    International Nuclear Information System (INIS)

    Zhang Ruijin; Castel, Arnaud; Francois, Raoul

    2010-01-01

    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.

  4. Corrosion and mechanical performance of AZ91 exposed to simulated inflammatory conditions.

    Science.gov (United States)

    Brooks, Emily K; Der, Stephanie; Ehrensberger, Mark T

    2016-03-01

    Magnesium (Mg) and its alloys, including Mg-9%Al-1%Zn (AZ91), are biodegradable metals with potential use as temporary orthopedic implants. Invasive orthopedic procedures can provoke an inflammatory response that produces hydrogen peroxide (H2O2) and an acidic environment near the implant. This study assessed the influence of inflammation on both the corrosion and mechanical properties of AZ91. The AZ91 samples in the inflammatory protocol were immersed for three days in a complex biologically relevant electrolyte (AMEM culture media) that contained serum proteins (FBS), 150 mM of H2O2, and was titrated to a pH of 5. The control protocol immersed AZ91 samples in the same biologically relevant electrolyte (AMEM & FBS) but without H2O2 and the acid titration. After 3 days all samples were switched into fresh AMEM & FBS for an additional 3-day immersion. During the initial immersion, inflammatory protocol samples showed increased corrosion rate determined by mass loss testing, increased Mg and Al ion released to solution, and a completely corroded surface morphology as compared to the control protocol. Although corrosion in both protocols slowed once the test electrolyte solution was replaced at 3 days, the samples originally exposed to the simulated inflammatory conditions continued to display enhanced corrosion rates as compared to the control protocol. These lingering effects may indicate the initial inflammatory corrosion processes modified components of the surface oxide and corrosion film or initiated aggressive localized processes that subsequently left the interface more vulnerable to continued enhanced corrosion. The electrochemical properties of the interfaces were also evaluated by EIS, which found that the corrosion characteristics of the AZ91 samples were potentially influenced by the role of intermediate adsorption layer processes. The increased corrosion observed for the inflammatory protocol did not affect the flexural mechanical properties of the AZ91

  5. General Corrosion and Localized Corrosion of the Drip Shield

    International Nuclear Information System (INIS)

    F. Hua

    2004-01-01

    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])

  6. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    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]).

  7. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    Unknown

    SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this ... corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed ..... Hou Baorong and Li Yantao 1998 Studia Marina Sinica 13 119.

  8. Hanford transuranic storage corrosion review

    International Nuclear Information System (INIS)

    Nelson, J.L.; Divine, J.R.

    1980-12-01

    The rate of atmospheric corrosion of the transuranic (TRU) waste drums at the US Department of Energy's Hanford Project, near Richland, Washington, was evaluated by Pacific Northwest Laboratory (PNL). The rate of corrosion is principally contingent upon the effects of humidity, airborne pollutants, and temperature. Results of the study indicate that actual penetration of barrels due to atmospheric corrosion will probably not occur within the 20-year specified recovery period. Several other US burial sites were surveyed, and it appears that there is sufficient uncertainty in the available data to prevent a clearcut statement of the corrosion rate at a specific site. Laboratory and site tests are recommended before any definite conclusions can be made. The corrosion potential at the Hanford TRU waste site could be reduced by a combination of changes in drum materials (for example, using galvanized barrels instead of the currently used mild steel barrels), environmental exposure conditions (for example, covering the barrels in one of numerous possible ways), and storage conditions

  9. Corrosion effects on friction factors

    International Nuclear Information System (INIS)

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

    1996-01-01

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

  10. Combining hygrothermal and corrosion models to predict corrosion of metal fasteners embedded in wood

    Science.gov (United States)

    Samuel L. Zelinka; Dominique Derome; Samuel V. Glass

    2011-01-01

    A combined heat, moisture, and corrosion model is presented and used to simulate the corrosion of metal fasteners embedded in solid wood exposed to the exterior environment. First, the moisture content and temperature at the wood/fastener interface is determined at each time step. Then, the amount of corrosion is determined spatially using an empirical corrosion rate...

  11. Quantitative measures of corrosion and prevention: application to corrosion in agriculture

    NARCIS (Netherlands)

    Schouten, J.C.; Gellings, P.J.

    1987-01-01

    The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in

  12. Some observations about the Incoloy 800 corrosion

    International Nuclear Information System (INIS)

    Baptista, W.; Sathler, L.; Mattos, O.R.

    1985-01-01

    The chemical and electrochemical characteristics of synthetic solutions similar to those inside the occluded cell corrosion - OCC (pitting, cracks from stress corrosion) of incoloy 800, 25 0 C are studied. (E.G.) [pt

  13. Corrosion problems in light water nuclear reactors

    International Nuclear Information System (INIS)

    Berry, W.E.

    1984-01-01

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

  14. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    Unknown

    alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides. Keywords. Corrosion; iron aluminides; Fe3Al; potentiodynamic polarization. 1. Introduction. Ordered intermetallic alloys based on iron aluminides of.

  15. Cracking of SHCC due to reinforcement corrosion

    NARCIS (Netherlands)

    Savija, B.; Lukovic, M.; Pacheco Farias, J.; Schlangen, H.E.J.G.; Saouma, V.; Bolander, J.; Landis, E.

    2016-01-01

    Reinforcement corrosion is the most important deterioration mechanism affecting reinforced concrete infrastructures. After corrosion starts, expansive pressures are exerted onto the surrounding concrete, causing cracking and spalling of the cover concrete. The amount of cover cracking can possibly

  16. Accelerated Test Method for Corrosion Protective Coatings

    Data.gov (United States)

    National Aeronautics and Space Administration — This project seeks to develop a new accelerated corrosion test method that predicts the long-term corrosion protection performance of spaceport structure coatings as...

  17. Rail base corrosion and cracking prevention

    Science.gov (United States)

    2014-07-01

    Rail base corrosion combined with fatigue or damage can significantly reduce rail life. Studies were done to examine the relative contribution of damage, corrosion, and fatigue on rail life. The combined effects can be separated into constituent fact...

  18. Microencapsulation of Corrosion Indicators for Smart Coatings

    Science.gov (United States)

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

    2011-01-01

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

  19. Corrosion product film-induced stress facilitates stress corrosion cracking

    OpenAIRE

    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 subst...

  20. Determining the long-term effects of H₂S concentration, relative humidity and air temperature on concrete sewer corrosion.

    Science.gov (United States)

    Jiang, Guangming; Keller, Jurg; Bond, Philip L

    2014-11-15

    Many studies of sewer corrosion are performed in accelerated conditions that are not representing the actual corrosion processes. This study investigated the effects of various factors over 3.5 years under controlled conditions simulating the sewer environment. Concrete coupons prepared from precorroded sewers were exposed, both in the gas phase and partially submerged in wastewater, in laboratory controlled corrosion chambers. Over the 45 month exposure period, three environmental factors of H2S concentration, relative humidity and air temperature were controlled at different levels in the corrosion chambers. A total of 36 exposure conditions were investigated to determine the long term effects of these factors by regular retrieval of concrete coupons for detailed analysis of surface pH, corrosion layer sulfate levels and concrete loss. Corrosion rates were also determined for different exposure periods. It was found that the corrosion rate of both gas-phase and partially-submerged coupons was positively correlated with the H2S concentration in the gas phase. Relative humidity played also a role for the corrosion activity of the gas-phase coupons. However, the partially-submerged coupons were not affected by humidity as the surfaces of these coupons were saturated due to capillary suction of sewage on the coupon surface. The effect of temperature on corrosion activity varied and possibly the acclimation of corrosion-inducing microbes to temperature mitigated effects of that factor. It was apparent that biological sulfide oxidation was not the limiting step of the overall corrosion process. These findings provide real insights into the long-term effects of these key environmental factors on the sewer corrosion processes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Microbiological corrosion of ASTM SA105 carbon steel pipe for industrial fire water usage

    Science.gov (United States)

    Chidambaram, S.; Ashok, K.; Karthik, V.; Venkatakrishnan, P. G.

    2018-02-01

    The large number of metallic systems developed for last few decades against both general uniform corrosion and localized corrosion. Among all microbiological induced corrosion (MIC) is attractive, multidisciplinary and complex in nature. Many chemical processing industries utilizes fresh water for fire service to nullify major/minor fire. One such fire water service line pipe attacked by micro-organisms leads to leakage which is industrially important from safety point of view. Also large numbers of leakage reported in similar fire water service of nearby food processing plant, paper & pulp plant, steel plant, electricity board etc…In present investigation one such industrial fire water service line failure analysis of carbon steel line pipe was analyzed to determine the cause of failure. The water sample subjected to various chemical and bacterial analyses. Turbidity, pH, calcium hardness, free chlorine, oxidation reduction potential, fungi, yeasts, sulphide reducing bacteria (SRB) and total bacteria (TB) were measured on water sample analysis. The corrosion rate was measured on steel samples and corrosion coupon measurements were installed in fire water for validating non flow assisted localized corrosion. The sulphide reducing bacteria (SRB) presents in fire water causes a localized micro biological corrosion attack of line pipe.

  2. Anodized titanium and stainless steel in contact with CFRP: an electrochemical approach considering galvanic corrosion.

    Science.gov (United States)

    Mueller, Yves; Tognini, Roger; Mayer, Joerg; Virtanen, Sannakaisa

    2007-09-15

    The combination of different materials in an implant gives the opportunity to better fulfill the requirements that are needed to improve the healing process. However, using different materials increases the risk of galvanic coupling corrosion. In this study, coupling effects of gold-anodized titanium, stainless steel for biomedical applications, carbon fiber reinforced polyetheretherketone (CFRP), and CFRP containing tantalum fibers are investigated electrochemically and by long-term immersion experiments in simulated body fluid (SBF). Potentiodynamic polarization experiments (i/E curves) and electrochemical impedance spectroscopy (EIS) of the separated materials showed a passive behavior of the metallic samples. Anodized titanium showed no corrosion attacks, whereas stainless steel is highly susceptibility for localized corrosion. On the other side, an active dissolution behavior of both of the CFRPs in the given environment could be determined, leading to delaminating of the carbon fibers from the matrix. Long-term immersion experiments were carried out using a set-up especially developed to simulate coupling conditions of a point contact fixator system (PC-Fix) in a biological environment. Electrochemical data were acquired in situ during the whole immersion time. The results of the immersion experiments correlate with the findings of the electrochemical investigation. Localized corrosion attacks were found on stainless steel, whereas anodized titanium showed no corrosion attacks. No significant differences between the two CFRP types could be found. Galvanic coupling corrosion in combination with crevice conditions and possible corrosion mechanisms are discussed. Copyright 2007 Wiley Periodicals, Inc.

  3. Biodegradable magnesium alloys for orthopaedic applications: A review on corrosion, biocompatibility and surface modifications.

    Science.gov (United States)

    Agarwal, Sankalp; Curtin, James; Duffy, Brendan; Jaiswal, Swarna

    2016-11-01

    Magnesium (Mg) and its alloys have been extensively explored as potential biodegradable implant materials for orthopaedic applications (e.g. Fracture fixation). However, the rapid corrosion of Mg based alloys in physiological conditions has delayed their introduction for therapeutic applications to date. The present review focuses on corrosion, biocompatibility and surface modifications of biodegradable Mg alloys for orthopaedic applications. Initially, the corrosion behaviour of Mg alloys and the effect of alloying elements on corrosion and biocompatibility is discussed. Furthermore, the influence of polymeric deposit coatings, namely sol-gel, synthetic aliphatic polyesters and natural polymers on corrosion and biological performance of Mg and its alloy for orthopaedic applications are presented. It was found that inclusion of alloying elements such as Al, Mn, Ca, Zn and rare earth elements provides improved corrosion resistance to Mg alloys. It has been also observed that sol-gel and synthetic aliphatic polyesters based coatings exhibit improved corrosion resistance as compared to natural polymers, which has higher biocompatibility due to their biomimetic nature. It is concluded that, surface modification is a promising approach to improve the performance of Mg-based biomaterials for orthopaedic applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. The effect of Electro Discharge Machining (EDM) on the corrosion resistance of dental alloys.

    Science.gov (United States)

    Ntasi, Argyro; Mueller, Wolf Dieter; Eliades, George; Zinelis, Spiros

    2010-12-01

    The aim of the present study was to evaluate the effect of Electro Discharge Machining (EDM) on the corrosion resistance of two types of dental alloys used for fabrication of implant retained superstructures. Two groups of specimens were prepared from a Co-Cr (Okta-C) and a grade II cpTi (Biotan) alloys respectively. Half of the specimens were subjected to EDM with Cu electrodes and the rest were conventionally finished (CF). The corrosion resistance of the alloys was evaluated by anodic polarization in Ringer's solution. Morphological and elemental alterations before and after corrosion testing were studied by SEM/EDX. Six regions were analyzed on each surface before and after corrosion testing and the results were statistically analyzed by paired t-test (a=0.05). EDM demonstrated inferior corrosion resistance compared to CF surfaces, the latter being passive in a wider range of potential demonstrating higher polarization resistance and lower I(corr) values. Morphological alterations were found before and after corrosion testing for both materials tested after SEM analysis. EDX showed a significant decrease in Mo, Cr, Co, Cu (Co-Cr) and Ti, Cu (cpTi) after electrochemical testing plus an increase in C. According to the results of this study the EDM procedure decreases the corrosion resistance of both the alloys tested, increasing thus the risk of possible adverse biological reactions. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  5. Smart Coatings for Launch Site Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.

    2014-01-01

    Smart, environmentally friendly paint system for early corrosion detection, mitigation, and healing that will enable supportability in KSC launch facilities and ground systems through their operational life cycles. KSC's Corrosion Technology Laboratory is developing a smart, self-healing coating that can detect and repair corrosion at an early stage. This coating is being developed using microcapsules specifically designed to deliver the contents of their core when corrosion starts.

  6. Marine atmospheric corrosion of carbon steels

    OpenAIRE

    Morcillo, Manuel; Alcántara, Jenifer; Díaz, Iván; Chico, Belén; Simancas, Joaquín; de la Fuente, Daniel

    2015-01-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products...

  7. Filiform corrosion formation on painted aluminium extrusions

    Energy Technology Data Exchange (ETDEWEB)

    Nordlien, J.H. [SINTEF Materials Technology, Trondheim (Norway). Dept. of Corrosion and Surface Technology; Defrancq, J. [Lab. for Strength of Materials and Welding Technology, Univ. of Gent (Belgium); Zuest, W. [Algroup Alusuisse, Technology Center, Neuhausen (Switzerland); Benmalek, M. [Pechiney, Centre de Recherches de Voreppe, Voreppe (France); Stuckart, R. [Hydro Aluminium Extrusion, Lausanne (Switzerland)

    2000-07-01

    The filiform corrosion susceptibility of extruded, chromated and coated AA 6060/6063 alloys has been investigated. It is shown that, provided sufficient metal is removed before chromating, these alloys will exhibit high filiform corrosion resistance. In those cases where extensive filiform corrosion attack is observed during corrosion testing it is shown to be due to a reactive surface region, formed during the thermo-mechanical processing of the alloy and remaining after chemical pretreatment for painting. (orig.)

  8. Corrosion monitoring using FSM technology

    International Nuclear Information System (INIS)

    Strommen, R.; Horn, H.; Gartland, P.O.; Wold, K.; Haroun, M.

    1995-01-01

    FSM is a non-intrusive monitoring technique based on a patented principle, developed for the purpose of detection and monitoring of both general and localized corrosion, erosion, and cracking in steel and metal structures, piping systems, and vessels. Since 1991, FSM has been used for a wide range of applications, including for buried and open pipelines, process piping offshore, subsea pipelines and flowlines, applications in the nuclear power industry, and in materials, research in general. This paper describes typical applications of the FSM technology, and presents operational experience from some of the land-based and subsea installations. The paper also describes recent enhancements in the FSM technology and in the analysis of FSM readings, allowing for monitoring and detailed quantification of pitting and mesa corrosion, and of corrosion in welds

  9. Electrochemical corrosion of metallic biomaterials.

    Science.gov (United States)

    Pourbaix, M

    1984-05-01

    Methods of electrochemical thermodynamics (electrode potential-pH equilibrium diagrams) and electrochemical kinetics (polarization curves) may help to understand and predict the corrosion behaviour of metals and alloys in the presence of body fluids. A short review of the literature is given concerning some applications of such methods, both in vitro and in vivo, relating to surgical implants (stainless steels, chromium-cobalt-molybdenum alloys, titanium and titanium alloys) and to dental alloys (silver-tin-copper amalgams, silver-base and gold-base casting alloys, nickel-base casting alloys). Attention is drawn to the necessity of more basic research on crevice- and fretting-corrosion of surgical implant materials and dental alloys, and to the toxicity of corrosion products. A perfect understanding of the exact significance of electrode-potentials is essential for the success of such a task.

  10. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... the supersaturated alloy, into a diverse carbide network. Finally, the foils turn into metal dust accompanied by a thinning and disappearance of the foils. Investigations of TEM samples, prepared by means of FIB, on the carbide network revealed a lamellar structure with carbides and austenite. Finally, the mutual...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting...

  11. Investigation of adding fluoroapatite nanoparticles on compressive strength and corrosion behaviour of dental amalgams

    Directory of Open Access Journals (Sweden)

    Fahimeh Mirlohi

    2012-12-01

    Full Text Available In recent years, there have been many efforts to improve biological and biocompatibility features of amalgam. The aim of this research was investigating the effect of adding fluoroapatite (FA nanoparticles on compressive strength and corrosion behaviour of dental amalgam. An amalgam alloy powder was mixed with 1, 3 and 5 wt.% of FA nanoparticles to form composite powders. Compressive strength of the corresponding dental amalgam samples was measured on the first and seventh day after preparation and the corrosion behaviour was investigated by potentiodynamic polarization electrochemical test in 0.9 wt.% salt solution (physiologic serum. The results showed that the amalgam containing 1 wt.% FA nanoparticles has higher compressive strength then the pure amalgam and with increasing the FA content in amalgam to 3 and 5 wt.%, the compressive strength decreases. The results also indicated that the corrosion behaviour of the amalgam sample with 1 wt.% FA is similar to the corrosion behaviour of the original amalgam, while with increasing the weight percentage of fluorapatite, the corrosion resistance decreases. The results of this research showed that adding FA nanoparticles in amounts of up to 1 wt.% to amalgam alloy improve compressive strength, has no destructive effect on corrosion behaviour of the material and can increase its biocompatibility and biological activity.

  12. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of ...

  13. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Li, Wenyan; Buhrow, Jerry W.; Jolley, Scott T.

    2010-01-01

    Corrosion is a destructive process that often causes failure in metallic components and structures. 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 control it. The multi-functionality of the coating is based on microencapsulation technology specifically designed for corrosion control applications. This design has, in addition to all the advantages of other existing microcapsules designs, the corrosion controlled release function that allows the delivery of corrosion indicators and inhibitors on demand only when and where they are needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into the microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy.

  14. 49 CFR 193.2625 - Corrosion protection.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Corrosion protection. 193.2625 Section 193.2625...: FEDERAL SAFETY STANDARDS Maintenance § 193.2625 Corrosion protection. (a) Each operator shall determine which metallic components could, unless corrosion is controlled, have their integrity or reliability...

  15. Corrosion inhibitor testing in archaeological conservation

    Directory of Open Access Journals (Sweden)

    Robert Faltermeier

    1997-11-01

    Full Text Available Metal objects from archaeological contexts often suffer serious damage by corrosion. Various methods for inhibiting corrosion have been developed, but their effects need to be evaluated. Here new research is described on how treatments to inhibit the corrosion of copper and copper-alloy artefacts may be tested.

  16. Corrosion and chemical resistant masonry materials handbook

    National Research Council Canada - National Science Library

    Sheppard, Walter Lee

    1986-01-01

    ... and other equipment. But few other than chemists and chemical engineers identify "corrosion" as chemical degradation or destruction of a material, and therefore, something that can happen to nonmetals (concrete, plastics, brick, timber, etc.) as well as to nletals. The National Association of Corrosion Engineers so defined "corrosion" over thirty years ago but this f...

  17. The Corrosivity of the Mauritian Atmosphere

    African Journals Online (AJOL)

    Nafiisah

    the outdoor exposure of carbon steel samples of commercial quality. They were exposed at three sites, ... 25% of this cost could be avoided by using appropriate corrosion control technology. Atmospheric corrosion is ... then compared with ISO 9223 to determine the corrosivity of the atmosphere at the three different sites.

  18. Electrochemical Measurement of Atmospheric Corrosion

    Science.gov (United States)

    DeArmond, Anna H.; Davis, Dennis D.; Beeson, Harold D.

    1999-01-01

    Corrosion of Shuttle thruster components in atmospheres containing high concentrations of nitrogen tetroxide (NTO) and water is an important issue in ground operations of bipropellant systems in humid locations. Measurements of the corrosivities of NTO-containing atmospheres and the responses of different materials to these atmospheres have been accomplished using an electrochemical sensor. The sensor is composed of alternating aluminum/titanium strips separated by thin insulating layers. Under high humidity conditions a thin film of water covers the surface of the sensor. Added NTO vapor reacts with the water film to form a conductive medium and establishes a galvanic cell. The current from this cell can be integrated with respect to time and related to the corrosion activity. The surface layer formed from humid air/NTO reacts in the same way as an aqueous solution of nitric acid. Nitric acid is generally considered an important agent in NTO corrosion situations. The aluminum/titanium sensor is unresponsive to dry air, responds slightly to humid air (> 75% RH), and responds strongly to the combination of humid air and NTO. The sensor response is a power function (n = 2) of the NTO concentration. The sensor does not respond to NTO in dry air. The response of other materials in this type of sensor is related to position of the material in a galvanic series in aqueous nitric acid. The concept and operation of this electrochemical corrosion measurement is being applied to other corrosive atmospheric contaminants such as hydrogen chloride, hydrogen fluoride, sulfur dioxide, and acidic aerosols.

  19. Morphological kinetics and localized corrosion

    International Nuclear Information System (INIS)

    Santarini, G.

    1992-01-01

    A phenomenological modeling is proposed for physicochemical systems that evolve by initiation and growth of well distinct defects. It consists in a mathematical treatment of data on the evolution of defect distribution, which leads to the knowledge of evolution parameters ultimately usable for behaviour predictions. A method is given for calculating a validity parameter which quantifies the pertinence of the choice for analytical representations. An example of application to localized corrosion is given with the intergranular stress corrosion cracking of Alloy 600 in high temperature water. (Author). 6 refs

  20. Corrosion problems of power engineering

    International Nuclear Information System (INIS)

    1987-12-01

    The proceedings of the conference Corrosion Problems of Power Engineering held from 8 to 10 Dec 1987 in Marianske Lazne (CS) contain the full texts of 26 papers of which 12 fall under the INIS Subject Scope. The papers discuss structural materials for the components of the primary and secondary coolant circuits of nuclear power plants with WWER type reactors. Attention is devoted to various aspects of corrosion behaviour of the materials during normal operation of a nuclear power plant and in deactivation agents. (Z.M.)

  1. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  2. Corrosion Reliability of Electronic Systems

    DEFF Research Database (Denmark)

    Ambat, Rajan; Jensen, Stine G.; Møller, Per

    2008-01-01

    Inherently two factors namely multi-material usage and potential bias makes electronic devices susceptible to corrosion if exposed to humid conditions. The problem is compounded today due to miniaturization and contamination effects. The reduction in size of the components and close spacing...... on a Printed Circuit Board (PCB) for high density packing has greatly increased the risk of corrosion under humid conditions. An important issue is the failures due to electrolytic metal migration. This paper describes an investigation of the electrolytic migration of Sn-Pb solder lines on PCBs in humid...

  3. When can Electrochemical Techniques give Reliable Corrosion Rates on Carbon Steel in Sulfide Media?

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, Tor; Nielsen, Lars Vendelbo

    2005-01-01

    Effects of film formation on carbon steel in hydrogen sulfide media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from hydrogen sulfide solutions, biological sulfide media and natural sulfide containing geothermal water have been collected and the process...... of film formation in sulfide solutions was followed by video. It can be shown that capacitative and diffusional effects due to porous reactive deposits tend to dominate the data resulting in unreliable corrosion rates measured by electrochemical techniques. The effect is strongly increased if biofilm...... corrosion rates, but this effect may not be detected if rates are already overestimated. It is concluded that electrochemical techniques can be used for corrosion rate monitoring in som hydrogen sulfide media, but care must be taken when choosing the scan rates, and it is important to realize when direct...

  4. Bioaccumulation and food chain transfer of corrosion products from radioactive stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Young, J.S.

    1986-07-01

    Two sets of experiments were conducted to determine if corrosion products from radioactive Type 347 stainless steel could be biologically transferred from sediment through a marine food chain, and whether corrosion products dissolved in seawater could be bioaccumulated and then eliminated. Corrosion products containing /sup 60/Co and /sup 63/Ni from the radioactive stainless steel were introduced into marine sediments. Infaunal polychaete worms exposed to these sediments bioaccumulated the radionuclides. The feeding of these worms to shrimp and fish resulted in a trophic transfer of the radioactive products across a one-step food chain. The magnitude of the transfers are described in terms of transfer factors. Dissolved corrosion products as measured by the radionuclides were also bioaccumulated by shrimp and fish concentrating more than fish. Concentration factors were calculated.

  5. pitting corrosion susceptibility pitting corrosion susceptibility of aisi ...

    African Journals Online (AJOL)

    eobe

    The susceptibility of austenitic (AISI 301) stainless steel to pitting corrosion was evaluated in sodium chloride ... halides, the most aggressive and thus, the most frequently investigated is the chloride ions, particularly its effect on pit formation in 18/8 stainless steel [1 - 3]. ... in sea water), and moderately high temperatures.

  6. Application of Corrosion Test for Austenitic SS 304 in PWR with Electrochemical Quartz Crystal Microbalance (EQCM)

    International Nuclear Information System (INIS)

    Park, Jeong Seok; Shin, Sang Hun; Kim, Jong Jin; Kim, Ji Hyun

    2011-01-01

    The secondary system of a pressurized water reactor (PWR) is a loop composed of: a) steam generator, b) steam transport piping, c) steam turbine and d) condenser and some optional component. The materials of these components are mainly carbon steel, different grades of stainless steel, high nickel alloys (Inconel-600 and Incoloy-800), Copper alloys. Among these materials, austenitic stainless steel 304 is widely used in tubing for large-surface condenser exposed to seawater as coolant of steam condenser. Stainless steels show much greater resistance to erosion-corrosion than copper alloys used in steam condenser tubing and are also immune to ammonia attack, ammonia induced stress corrosion cracking. Also, the chloride induced stress corrosion cracking has not been reported in stainless steel tubing in power plant condenser. Nevertheless, it is well known that stainless steels are susceptible to pitting and crevice corrosion in the seawater environment including chloride ions. Metallic materials exposed to untreated seawater suffer the well-known phenomenon of fouling consisting of the formation of an unwanted deposit that covers the surfaces in contact with the water. Five types of fouling are usually considered as biological, corrosion, particulate, chemical and precipitation fouling. Pitting corrosion is aggravated by stagnant or low flow conditions in which sludge such as corrosion of copper alloys in the secondary system can form in the tube surface. From the operational maintenance viewpoint, pitting attack has destructive effect of structural materials on operation of NPP. Countermeasures such as copper alloys replacement, water chemistry control and chemical cleaning were implemented to mitigate the pitting. Although the many studies are performed macroscopically to reduce pitting corrosion in the secondary system, little work has been done to understand mechanism of fouling formation and to confirm the quantitative analysis of the fouling between the metal

  7. 219-S CORROSION STUDY

    International Nuclear Information System (INIS)

    DIVINE, J.R.; PARSONS, G.L.

    2008-01-01

    A minor leak was detected in a drain line for Hood 2B located in the 222-S Laboratory. The line transfers radioactive waste, spent analytical standards, and chemicals used in various analytical procedures. Details are in the report provided by David Comstock, 2B NDE June 2008, work package LAB-WO-07-2012. Including the noted leak, the 222-S Laboratory has experienced two drain line leaks in approximately the last two years of operation. As a consequence, CH2M HILL Hanford Group, Inc. (CH2M HILL) requested the support of ChemMet, Ltd., PC (ChemMet) at the Hanford Site 222-S Laboratory. The corrosion expertise from ChemMet was required prior to preparation of a compatibility assessment for the 222-S Laboratory waste transfer system to assure the expected life of the piping system is extended as much as practicable. The system includes piping within the 222-S Laboratory and the 219-S Waste Storage and Transfer Facility and Operations Process. The ChemMet support was required for an assessment by 222-S staff to analyze what improvements to operational activities may be implemented to extend the tank/piping system life. This assessment will include a summary of the various material types, age, and locations throughout the facility. The assessment will also include a discussion of materials that are safe for drain line disposal on a regular basis, materials that are safe for disposal on a case-by-case basis including specific additional requirements such as flushing, neutralization to a specific pH, and materials prohibited from disposal. The assessment shall include adequate information for 222-S Laboratory personnel to make informed decisions in the future disposal of specific material types by discussing types of compatibility of system materials and potential wastes. The assessment is expected to contain some listing of acceptable waste materials but is not anticipated to be a complete or comprehensive list. Finally the assessment will encompass a brief discussion of

  8. Assessing Level and Effectiveness of Corrosion Education in the UAE

    Directory of Open Access Journals (Sweden)

    Hwee Ling Lim

    2012-01-01

    Full Text Available The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates had insufficient knowledge of corrosion engineering and superficial understanding of corrosion in real-life design contexts. The effectiveness of corrosion education is determined by both competence in corrosion knowledge/skills and availability of resources (faculty and research. Though most departments would not hire new corrosion-specialist faculty, department research efforts and industry partnerships in corrosion research were present. The paper concluded with recommendations for improving knowledge and skills of future engineers in corrosion and enhancing corrosion instruction to better meet industry needs.

  9. Liquid metal corrosion considerations in alloy development

    International Nuclear Information System (INIS)

    Tortorelli, P.F.; DeVan, J.H.

    1984-01-01

    Liquid metal corrosion can be an important consideration in developing alloys for fusion and fast breeder reactors and other applications. Because of the many different forms of liquid metal corrosion (dissolution, alloying, carbon transfer, etc.), alloy optimization based on corrosion resistance depends on a number of factors such as the application temperatures, the particular liquid metal, and the level and nature of impurities in the liquid and solid metals. The present paper reviews the various forms of corrosion by lithium, lead, and sodium and indicates how such corrosion reactions can influence the alloy development process

  10. Biological clocks: riding the tides.

    Science.gov (United States)

    de la Iglesia, Horacio O; Johnson, Carl Hirschie

    2013-10-21

    Animals with habitats in the intertidal zone often display biological rhythms that coordinate with both the tidal and the daily environmental cycles. Two recent studies show that the molecular components of the biological clocks mediating tidal rhythms are likely different from the phylogenetically conserved components that mediate circadian (daily) rhythms. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Corrosion of UN in water

    International Nuclear Information System (INIS)

    Sunder, S.; Miller, N.H.

    1996-10-01

    Corrosion of UN in water was investigated as a function of pH and temperature using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and by measuring the amount of ammonia formed due to its corrosion. The XPS results indicate that a freshly fractured surface of UN is quickly converted to U0 2 on exposure to liquid water or water vapours at ambient temperatures. These results show that UN is unstable in contact with water. The corrosion rate of UN is estimated to be ≥40 μmol·m -2 ·h -1 in deaerated water at ∼92 o C. There was no significant difference in corrosion rates measured in water at initial pHs of ∼6 and ∼10.3. These results contradict the literature reports stating that UN is stable in contact with boiling water. The implications of these results on the suitability of UN as a nuclear fuel for reactors are discussed. (author)

  12. Tubing with high corrosion resistance

    Science.gov (United States)

    Ioffe, A. V.; Tetyueva, T. V.; Vyboyshchik, M. A.; Trifonova, E. A.; Lutsenko, E. S.

    2010-07-01

    The optimum chemical composition and the regime for heat treatment of heat-resistant steel 15Kh5M are determined for the production of tubing with strength of group L80 (API 5CT) and high cold resistance and resistance to carbon dioxide and sulfurated hydrogen corrosion at low alloying additives of chromium and molybdenum.

  13. Less-toxic corrosion inhibitors

    Science.gov (United States)

    Humphries, T. S.

    1981-01-01

    Combinations of borates, nitrates, phosphates, silicates, and sodium MBT protect aluminum from corrosion in fresh water. Most effective combinations contained sodium phosphate and were alkaline. These inhibitors replace toxic chromates which are subject to governmental restrictions, but must be used in larger quantities. Experimental exposure times varied from 1 to 14 months depending upon nature of submersion solution.

  14. Automated methods of corrosion measurement

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers; Reeve, John Ch

    1997-01-01

    to revise assumptions regarding the basis of the method, which sometimes leads to the discovery of as-yet unnoticed phenomena. The present selection of automated methods for corrosion measurements is not motivated simply by the fact that a certain measurement can be performed automatically. Automation...

  15. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  16. Predicting the Performance of Organic Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    David A. Winkler

    2017-12-01

    Full Text Available The withdrawal of effective but toxic corrosion inhibitors has provided an impetus for the discovery of new, benign organic compounds to fill that role. Concurrently, developments in the high-throughput synthesis of organic compounds, the establishment of large libraries of available chemicals, accelerated corrosion inhibition testing technologies, and the increased capability of machine learning methods have made discovery of new corrosion inhibitors much faster and cheaper than it used to be. We summarize these technical developments in the corrosion inhibition field and describe how data-driven machine learning methods can generate models linking molecular properties to corrosion inhibition that can be used to predict the performance of materials not yet synthesized or tested. We briefly summarize the literature on quantitative structure–property relationships models of small organic molecule corrosion inhibitors. The success of these models provides a paradigm for rapid discovery of novel, effective corrosion inhibitors for a range of metals and alloys in diverse environments.

  17. Corrosion Control in the Aerospace Industry

    Science.gov (United States)

    Calle, Luz Marina; Li, Wenyan; 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..

  18. Evolutionary Computation Techniques for Predicting Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Amine Marref

    2013-01-01

    Full Text Available Corrosion occurs in many engineering structures such as bridges, pipelines, and refineries and leads to the destruction of materials in a gradual manner and thus shortening their lifespan. It is therefore crucial to assess the structural integrity of engineering structures which are approaching or exceeding their designed lifespan in order to ensure their correct functioning, for example, carrying ability and safety. An understanding of corrosion and an ability to predict corrosion rate of a material in a particular environment plays a vital role in evaluating the residual life of the material. In this paper we investigate the use of genetic programming and genetic algorithms in the derivation of corrosion-rate expressions for steel and zinc. Genetic programming is used to automatically evolve corrosion-rate expressions while a genetic algorithm is used to evolve the parameters of an already engineered corrosion-rate expression. We show that both evolutionary techniques yield corrosion-rate expressions that have good accuracy.

  19. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  20. NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

    Science.gov (United States)

    Calle, Luz Marina

    2015-01-01

    The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in North America. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the highly corrosive hydrochloric acid (HCl) generated by the solid rocket boosters (SRBs). Numerous failures at the launch pads are caused by corrosion. The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. NASA has over fifty years of experience dealing with unexpected failures caused by corrosion and has developed expertise in corrosion control in the launch and other environments. The Corrosion Technology Laboratory at KSC evolved, from what started as an atmospheric exposure test site near NASAs launch pads, into a capability that provides technical innovations and engineering services in all areas of corrosion for NASA, external partners, and customers.This paper provides a chronological overview of NASAs role in anticipating, managing, and preventing corrosion in highly corrosive environments. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

  1. Future and benefits of corrosion research

    International Nuclear Information System (INIS)

    Staehle, Roger W.

    2002-01-01

    The subject of corrosion is a design science. The subject of stress analysis is a design science as is the subject of heat transfer. When the subject of corrosion is considered in the framework design a clear framework of the priorities and objectives becomes apparent. Further, corrosion becomes a more explicit and important subject in the overall design, manufacturing, and operation phases of equipment: in this framework, the funding and support of corrosion work is necessary to the designers and users of equipment. The subject of corrosion is usually less important in the early stages of operation of equipment: in these early stages, the subjects. Corrosion becomes important to the longer term reliability and safety of equipment. Corrosion is often a principal determiner of design life. Corrosion is often more important after the manufacturing warranty is expired: therefore the subject is often more important to the user than to the manufacturer. In order that the subject of corrosion is considered and incorporated in the design as well as in user specifications, there must be a language and means of easily understood communication between the design-operation community and the corrosion community. For example, the designers do not understand the language of 'pitting potential': rather, they understand design life and permissible stress. Thus, corrosion must be put into terms that can be understood and utilized by designers and operators. Two methodologies have been developed for communicating effectively between the corrosion and the design communities: these are the 'Corrosion Based Design Approach' and the 'Location for Analysis Matrix.' These provide simple check off lists to designers for asking questions and assuring that credible answers have been obtained on issues that affect reliable and economic performance. Both of these subject are discussed in this presentation. The future of corrosion research is its effective linkage with design and operation of

  2. A Focus on Polarity: Investigating the Role of Orientation Cues in Mediating Student Performance on mRNA Synthesis Tasks in an Introductory Cell and Molecular Biology Course

    Science.gov (United States)

    Olimpo, Jeffrey T.; Quijas, Daniel A.; Quintana, Anita M.

    2017-01-01

    The central dogma has served as a foundational model for information flow, exchange, and storage in the biological sciences for several decades. Despite its continued importance, however, recent research suggests that novices in the domain possess several misconceptions regarding the aforementioned processes, including those pertaining…

  3. Trade-offs in parasitism efficiency and brood size mediate parasitoid coexistence, with implications for biological control of the invasive emerald ash borer

    Science.gov (United States)

    Parasitoids often are selected for use as biological control agents because of their high host specificity, yet such host specificity can result in strong interspecific competition. However, few studies have examined if and how various extrinsic factors (such as parasitism efficiency) influence the ...

  4. Quantitative measures of corrosion and prevention: application to corrosion in agriculture

    OpenAIRE

    Schouten, J.C.; Gellings, P.J.

    1987-01-01

    The corrosion protection factor (c.p.f.) and the corrosion condition (c.c.) are simple instruments for the study and evaluation of the contribution and efficiency of several methods of corrosion prevention and control. The application of c.p.f. and c.c. to corrosion and prevention in agriculture in The Netherlands is considered in detail. Attention is paid to relations between c.p.f. and c.c., the corrosion costs, possible cost savings and the applied corrosion protection scheme on farms. It ...

  5. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    Science.gov (United States)

    Buhrow, Jerry; Li, Wenyan; Jolley, Scott; Calle, Luz M.

    2011-01-01

    A multifunctional, smart coating for the autonomous control of corrosion is being developed based on micro-encapsulation technology. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection effectiveness. This paper summarizes the development, optimization, and testing of microcapsules specifically designed to be incorporated into a smart coating that will deliver corrosion inhibitors to mitigate corrosion autonomously. Key words: smart coating, corrosion inhibition, microencapsulation, microcapsule, pH sensitive microcapsule, corrosion inhibitor, corrosion protection pain

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

    Science.gov (United States)

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

    2015-06-11

    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.

  7. Civil Engineering Corrosion Control. Volume 1. Corrosion Control - General

    Science.gov (United States)

    1975-01-01

    inum by electrolysis and partly by re-forming the film. In time, the layer of corrosion products formed maintains an alkaline condition at the aluminum... brines , strong, hot caustic solutions, hydro- fluoric and hydrofluosilicic acids, hot sulfates and sul- fites, sulfurous acid, phosphoric acid, and...and fractionating towers, brine and sea water applications 317 Process equipment involving strong acids or chlor- inated solvents 321 Furnace parts in

  8. Corrosion Protection of Electrically Conductive Surfaces

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-11-01

    Full Text Available The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is a relative movement between electrical contacts with surfaces of ignoble metal. Avoiding fretting corrosion is therefore extremely challenging in electronic devices with pluggable electrical connections. Gold is one of the most commonly used noble plating materials for high performance electrical contacts because of its high corrosion resistance and its good and stable electrical behavior. The authors have investigated different ways to minimize the consumption of gold for electrical contacts and to improve the performance of gold plating. Other plating materials often used for corrosion protection of electrically conductive surfaces are tin, nickel, silver and palladium. This paper will deal with properties and new research results of different plating materials in addition to other means used for corrosion protection of electrically conductive surfaces and the testing of corrosion resistance of electrically conductive surfaces.

  9. Development of green vapour corrosion inhibitor

    Science.gov (United States)

    Asmara, Y. P.; Suraj, V.; Siregar, J. P.; Kurniawan, T.; Bachtiar, D.; Mohamed, N. M. Z. N.

    2017-10-01

    Corrosion control using inhibitor is an effective method to protect carbon steel from corrosion. Due to environmental toxicity of chemical inorganic corrosion inhibitors (synthetic), green inhibitors are potentially to develop. In atmospheric conditions, green vapour corrosion inhibitors are the best solutions to replace the uses of inorganic corrosion inhibitors. This research used chemical acid extraction from the key lime (citrus aurantiifolia) leaves and seeds. They are used as the main ingredients to produce this effective green corrosion inhibitor. The experiments investigated effects of corrosion inhibition on corrosion rate of low carbon steel in 3% NaCl solution using both fog salt chamber and electrochemical cell. Using salt fog chamber to represent atmospheric conditions, and corrosion rates are evaluated visually and calculated using weight loss methods. Corrosion rate on electrochemical cell were calculated using linear polarization resistance (LPR) methods. All of the experiments were set in natural conditions at pH 7. Using weight loss for three days exposure time, the efficiency of the inhibitor reached 82.39%.

  10. Analysis of corrosive environmental factors of seabed sediment

    Indian Academy of Sciences (India)

    Unknown

    relation between distance from seashore and corrosivity of seabed sediment. Keywords. Seabed sediment; corrosion; environmental factors. 1. Introduction. The corrosion due to seabed sediment is an important branch of corrosion research. The problem of metal corrosion in seabed sediments has become more and more.

  11. 49 CFR 192.477 - Internal corrosion control: Monitoring.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Internal corrosion control: Monitoring. 192.477... Control § 192.477 Internal corrosion control: Monitoring. If corrosive gas is being transported, coupons... internal corrosion. Each coupon or other means of monitoring internal corrosion must be checked two times...

  12. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    Unknown

    corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here. Keywords. ... The corrosion rate at high temperature can be four times bigger than at low temperature. ... exchange of substance and energy depends only on the surface SBS, therefore, it is ...

  13. Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study.

    Science.gov (United States)

    Liu, Yi-Yun; Wang, Yang; Walsh, Timothy R; Yi, Ling-Xian; Zhang, Rong; Spencer, James; Doi, Yohei; Tian, Guobao; Dong, Baolei; Huang, Xianhui; Yu, Lin-Feng; Gu, Danxia; Ren, Hongwei; Chen, Xiaojie; Lv, Luchao; He, Dandan; Zhou, Hongwei; Liang, Zisen; Liu, Jian-Hua; Shen, Jianzhong

    2016-02-01

    Until now, polymyxin resistance has involved chromosomal mutations but has never been reported via horizontal gene transfer. During a routine surveillance project on antimicrobial resistance in commensal Escherichia coli from food animals in China, a major increase of colistin resistance was observed. When an E coli strain, SHP45, possessing colistin resistance that could be transferred to another strain, was isolated from a pig, we conducted further analysis of possible plasmid-mediated polymyxin resistance. Herein, we report the emergence of the first plasmid-mediated polymyxin resistance mechanism, MCR-1, in Enterobacteriaceae. The mcr-1 gene in E coli strain SHP45 was identified by whole plasmid sequencing and subcloning. MCR-1 mechanistic studies were done with sequence comparisons, homology modelling, and electrospray ionisation mass spectrometry. The prevalence of mcr-1 was investigated in E coli and Klebsiella pneumoniae strains collected from five provinces between April, 2011, and November, 2014. The ability of MCR-1 to confer polymyxin resistance in vivo was examined in a murine thigh model. Polymyxin resistance was shown to be singularly due to the plasmid-mediated mcr-1 gene. The plasmid carrying mcr-1 was mobilised to an E coli recipient at a frequency of 10(-1) to 10(-3) cells per recipient cell by conjugation, and maintained in K pneumoniae and Pseudomonas aeruginosa. In an in-vivo model, production of MCR-1 negated the efficacy of colistin. MCR-1 is a member of the phosphoethanolamine transferase enzyme family, with expression in E coli resulting in the addition of phosphoethanolamine to lipid A. We observed mcr-1 carriage in E coli isolates collected from 78 (15%) of 523 samples of raw meat and 166 (21%) of 804 animals during 2011-14, and 16 (1%) of 1322 samples from inpatients with infection. The emergence of MCR-1 heralds the breach of the last group of antibiotics, polymyxins, by plasmid-mediated resistance. Although currently confined to China

  14. [Study on corrosion resistance of three non-noble porcelain alloys].

    Science.gov (United States)

    Wu, Zhikai; Xu, Sheng; Li, Wei; Teng, Jin; Li, Ning

    2011-10-01

    To study the electrochemical corrosion behavior of Co-Cr, Ni-Cr and Ni-Cr-Be based porcelain alloys in NaCl solution. Five samples of each alloy were made respectively, electric polarization curve of each alloy was obtained using potentiodynamic polarization technique. Self-corrosion potential (E(corr)), self-corrosion current density (I(corr), passive region and transpassivation potential were tested. Microstructure and constituent was examined using scanning electron microscopy and energy dispersive spectroscopy. Co-Cr alloy possessed the most desirable corrosion resistance because of its integrated, homogeneous and compact passive film. The poor compactness of Ni-Cr alloy's passive film decreased its corrosion resistance. Ni-Cr-Be alloy exhibited the worst corrosion resistance due to the Cr and Mo depleted Ni-Be eutectic phases in the alloy. Taking biological security into consideration, it is necessary to avoid the application of porcelain alloys with Be element. Co-Cr alloy with better biocompatibility possesses much broader prospect in the field of dental restoration.

  15. Detergent-Mediated Formation of β-Hematin: Heme Crystallization Promoted by Detergents Implicates Nanostructure Formation for Use as a Biological Mimic

    Science.gov (United States)

    2016-01-01

    Hemozoin is a unique biomineral that results from the sequestration of toxic free heme liberated as a consequence of hemoglobin degradation in the malaria parasite. Synthetic neutral lipid droplets (SNLDs) and phospholipids were previously shown to support the rapid formation of β-hematin, abiological hemozoin, under physiologically relevant pH and temperature, though the mechanism by which heme crystallization occurs remains unclear. Detergents are particularly interesting as a template because they are amphiphilic molecules that spontaneously organize into nanostructures and have been previously shown to mediate β-hematin formation. Here, 11 detergents were investigated to elucidate the physicochemical properties that best recapitulate crystal formation in the parasite. A strong correlation between the detergent’s molecular structure and the corresponding kinetics of β-hematin formation was observed, where higher molecular weight polar chains promoted faster reactions. The larger hydrophilic chains correlated to the detergent’s ability to rapidly sequester heme into the lipophilic core, allowing for crystal nucleation to occur. The data presented here suggest that detergent nanostructures promote β-hematin formation in a similar manner to SNLDs and phospholipids. Through understanding mediator properties that promote optimal crystal formation, we are able to establish an in vitro assay to probe this drug target pathway. PMID:27175104

  16. Modulation of human dermal microvascular endothelial cells by Sarcoptes scabiei in combination with proinflammatory cytokines, histamine, and lipid-derived biologic mediators

    Science.gov (United States)

    Elder, B. Laurel; Arlian, Larry G.; Morgan, Marjorie S.

    2009-01-01

    The ectoparasitic mite, Sarcoptes scabiei, produces molecules that depress initiation of host inflammatory and immune responses. Some of these down-regulate expression of adhesion molecules or secretion of chemokines or cytokines on and by cultured dermal endothelial cells (HMVEC-D). This study was undertaken to determine if the response of HMVEC-D to scabies is altered in the presence of various proinflammatory cytokines (tumor necrosis factor α and interleukins 1α, 1β and 6), histamine, and lipid-derived mediators (prostaglandins D2 and E2, leukotriene B4, platelet activation factor) that likely occur in scabietic lesions in vivo. Scabies extract down-regulated the TNFα-induced expression of VCAM-1 by HMVEC-D and this down-regulation still occurred in the presence of the other proinflammatory cytokines, histamine or the lipid-derived mediators. Scabies inhibited the IL-1α and IL-1β-induced secretion of IL-6, while a combination of scabies and histamine or LTB4 reduced the TNFα-induced secretion of IL-6. Scabies extract inhibited secretion of IL-8. Histamine, PGD2, PGE2, LTB4, PAF, and IL-6 alone had no effect on this inhibition, but the scabies-induced inhibition of IL-8 secretion was reduced in a dose-dependent fashion in the presence of IL-1α and IL-1β. PMID:19523846

  17. In Vitro Corrosion and Cytocompatibility of ZK60 Magnesium Alloy Coated with Hydroxyapatite by a Simple Chemical Conversion Process for Orthopedic Applications

    Science.gov (United States)

    Wang, Bing; Huang, Ping; Ou, Caiwen; Li, Kaikai; Yan, Biao; Lu, Wei

    2013-01-01

    Magnesium and its alloys—a new class of degradable metallic biomaterials—are being increasingly investigated as a promising alternative for medical implant and device applications due to their advantageous mechanical and biological properties. However, the high corrosion rate in physiological environments prevents the clinical application of Mg-based materials. Therefore, the objective of this study was to develop a hydroxyapatite (HA) coating on ZK60 magnesium alloy substrates to mediate the rapid degradation of Mg while improving its cytocompatibility for orthopedic applications. A simple chemical conversion process was applied to prepare HA coating on ZK60 magnesium alloy. Surface morphology, elemental compositions, and crystal structures were characterized using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction, respectively. The corrosion properties of samples were investigated by immersion test and electrochemical test. Murine fibroblast L-929 cells were harvested and cultured with coated and non-coated ZK60 samples to determine cytocompatibility. The degradation results suggested that the HA coatings decreased the degradation of ZK60 alloy. No significant deterioration in compression strength was observed for all the uncoated and coated samples after 2 and 4 weeks’ immersion in simulated body fluid (SBF). Cytotoxicity test indicated that the coatings, especially HA coating, improved cytocompatibility of ZK60 alloy for L929 cells. PMID:24300096

  18. Automated Methods of Corrosion Measurements

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1997-01-01

    Scanning probe microscopy (SPM) techniques rely on computer recordings of interactions between the tip of a minute probe and the surface of the small specimen as a function of position; the measurements are used to depict an image of the atomic-scale surface topography on the computer screen....... Mechanical control, recording, and data processing must therefore be automated to a high level of precision and reliability. These general techniques and the apparatus involved have been described extensively. The automated methods of such high-resolution microscopy coordinated with computerized...... electrochemical measurements as well as elemental analysis look very promising for elucidating corrosion reaction mechanisms. The study of initial surface reactions at the atomic or submicron level is becoming an important field of research in the understanding of corrosion processes. At present, mainly two...

  19. Space Shuttle Corrosion Protection Performance

    Science.gov (United States)

    Curtis, Cris E.

    2007-01-01

    The reusable Manned Space Shuttle has been flying into Space and returning to earth for more than 25 years. The launch pad environment can be corrosive to metallic substrates and the Space Shuttles are exposed to this environment when preparing for launch. The Orbiter has been in service well past its design life of 10 years or 100 missions. As part of the aging vehicle assessment one question under evaluation is how the thermal protection system and aging protective coatings are performing to insure structural integrity. The assessment of this cost resources and time. The information is invaluable when minimizing risk to the safety of Astronauts and Vehicle. This paper will outline a strategic sampling plan and some operational improvements made by the Orbiter Structures team and Corrosion Control Review Board.

  20. Corrosion of carbon steel welds

    International Nuclear Information System (INIS)

    Daniel, B.

    1988-09-01

    This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

  1. Corrosion scenario development for corrosion lifetime prediction of carbon steel used for geological disposal package

    International Nuclear Information System (INIS)

    Fukuda, Takanori; Nakayama, Guen; Akashi, Masatsune

    1994-01-01

    A corrosion scenario has been developed in an attempt to ensure the long-term integrity of carbon steel geological disposal packages for high-level nuclear waste. As the service life of the packages must span 1,000-10,000 years, the temperature, pH, and amount of oxygen, in the disposal facilities can hardly be expected to remain constant. Therefore, we clarified a system for predicting the corrosion lifetime of packages, taking into account long-term changes in the types of corrosion of carbon steel in disposal facilities relative to changes in the conditions of such facilities. This corrosion scenario charts the possible types of corrosion (i.e., general corrosion, stress corrosion cracking (SCC), and crevice corrosion) to which packages are subjected

  2. Reliability of Electrochemical Techniques for Determining Corrosion Rates on Carbon Steel in Sulfide Media

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Hemmingsen, T.; Nielsen, Lars Vendelbo

    2007-01-01

    Effects of film formation on carbon steel in hydrogen sulfide (H2S) media may corrupt corrosion rate monitoring by electrochemical techniques. Electrochemical data from H2S solutions, biological sulfide media, and natural sulfide containing geothermal water have been collected, and the process of...

  3. Castable hot corrosion resistant alloy

    Science.gov (United States)

    Barrett, Charles A. (Inventor); Holt, William H. (Inventor)

    1988-01-01

    Some 10 wt percent nickel is added to an Fe-base alloy which has a ferrite microstructure to improve the high temperature castability and crack resistance while about 0.2 wt percent zirconium is added for improved high temperatur cyclic oxidation and corrosion resistance. The basic material is a high temperature FeCrAl heater alloy, and the addition provides a material suitable for burner rig nozzles.

  4. Prevention of corrosion with polyaniline

    Science.gov (United States)

    MacDiarmid, Alan G. (Inventor); Ahmad, Naseer (Inventor)

    1997-01-01

    Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating.

  5. Corrosion-Activated Micro-Containers for Environmentally Friendly Corrosion Protective Coatings

    Science.gov (United States)

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

    2016-01-01

    This work concerns the development of environmentally friendly encapsulation technology, specifically designed to incorporate corrosion indicators, inhibitors, and self-healing agents into a coating, in such a way that the delivery of the indicators and inhibitors is triggered by the corrosion process, and the delivery of self-healing agents is triggered by mechanical damage to the coating. Encapsulation of the active corrosion control ingredients allows the incorporation of desired autonomous corrosion control functions such as: early corrosion detection, hidden corrosion detection, corrosion inhibition, and self-healing of mechanical damage into a coating. The technology offers the versatility needed to include one or several corrosion control functions into the same coating.The development of the encapsulation technology has progressed from the initial proof-of-concept work, in which a corrosion indicator was encapsulated into an oil-core (hydrophobic) microcapsule and shown to be delivered autonomously, under simulated corrosion conditions, to a sophisticated portfolio of micro carriers (organic, inorganic, and hybrid) that can be used to deliver a wide range of active corrosion ingredients at a rate that can be adjusted to offer immediate as well as long-term corrosion control. The micro carriers have been incorporated into different coating formulas to test and optimize the autonomous corrosion detection, inhibition, and self-healing functions of the coatings. This paper provides an overview of progress made to date and highlights recent technical developments, such as improved corrosion detection sensitivity, inhibitor test results in various types of coatings, and highly effective self-healing coatings based on green chemistry. The NASA Kennedy Space Centers Corrosion Technology Lab at the Kennedy Space Center in Florida, U.S.A. has been developing multifunctional smart coatings based on the microencapsulation of environmentally friendly corrosion

  6. Evaluation of corrosion attack of chimney liners

    Directory of Open Access Journals (Sweden)

    Blahetová M.

    2016-06-01

    Full Text Available The case study of chimney liner corrosion addresses three specific cases of damage of chimney systems from of stainless steels. These systems were used for flue of gas arising from the combustion of brown coal in small automatic boilers, which are used for heating. Detailed analyzes implied that the cause of devastating corrosion of the steel AISI 316 and 304 steel (CSN 17349, 17241 was particularly high content of halides (chlorides and fluorides, which caused a severe pitting corrosion, which led up to the perforation of the liner material. Simultaneous reduction of the thickness of the used sheets was due to by the general corrosion, which was caused by the sulfur in the solid fuel. The condensation then led to acid environment and therefore the corrosion below the dew point of the sulfuric acid has occurred. All is documented by metallographic analysis and microanalysis of the corrosion products.

  7. Corrosion monitoring during a chemical cleaning

    International Nuclear Information System (INIS)

    Delepine, J.; Feron, D.; Roy, M.

    1994-01-01

    In order to estimate the possible corrosion induced by the chemical cleaning, a corrosion monitoring has been realized during the cleaning of the secondary circuit (including the model boiler) of ORION loop. It included coupons and electrodes and has required a preliminary setting in laboratory. The electrochemical device which was used during the chemical cleaning included two reference electrodes (Ag/AgCl) and eight metallic electrodes (carbon steel, stainless steel, Alloy 600 and Alloy 690) for free corrosion potential monitoring, three other carbon steel electrodes for instantaneous corrosion rate measurements by polarization resistance and three coupling devices with different surface ratios between carbon steel and Alloy 600. The results showed a good agreement between corrosion rates measured by weight losses on coupons or by electrochemistry (polarization resistance), and an increase of the carbon steel corrosion rate when it was coupled with Alloy 600. (authors). 5 figs., 2 tabs., 3 refs

  8. Electrochemical corrosion testing of metal waste forms

    International Nuclear Information System (INIS)

    Abraham, D. P.; Peterson, J. J.; Katyal, H. K.; Keiser, D. D.; Hilton, B. A.

    1999-01-01

    Electrochemical corrosion tests have been conducted on simulated stainless steel-zirconium (SS-Zr) metal waste form (MWF) samples. The uniform aqueous corrosion behavior of the samples in various test solutions was measured by the polarization resistance technique. The data show that the MWF corrosion rates are very low in groundwaters representative of the proposed Yucca Mountain repository. Galvanic corrosion measurements were also conducted on MWF samples that were coupled to an alloy that has been proposed for the inner lining of the high-level nuclear waste container. The experiments show that the steady-state galvanic corrosion currents are small. Galvanic corrosion will, hence, not be an important mechanism of radionuclide release from the MWF alloys

  9. Corrosion studies of modified organosilane coated magnesium–yttrium alloy in different environments

    International Nuclear Information System (INIS)

    Xue Dingchuan; Tan Zongqing; Schulz, Mark J.; Vanooij, William J.; Sankar, Jagannathan; Yun Yeoheung; Dong Zhongyun

    2012-01-01

    Magnesium (Mg) and its alloys have numerous potential applications as biodegradable implants, but the fast degradation rate of Mg alloys at the initial implanted stage could be a problem. This paper describes the modification of the water-based bis-[triethoxysilyl] ethane (BTSE) silane applied to the surface of magnesium–yttrium (Mg–4Y) to increase its corrosion resistance. Surface characterization by SEM, FTIR, and EDX showed that the hydrolysis and condensation of the silane resulted in a covalent bonding to the Mg–4Y surface. Corrosion behavior of the uncoated and coated Mg–4Y alloy was evaluated in different environments by using a novel self-developed corrosion probe. Based on the electrochemical results of DC polarization and electrochemical impedance spectroscopy (EIS), we conclude that the epoxy-modified BTSE silane coating successfully increases the corrosion resistance at the initial stage of implantation. The corrosion rates in the flesh of dead mice environments such as body cavity and subcutaneous tissue of the mice were lower than the corrosion rates in in vitro environments. - Highlights: ► Modified silane was used on Mg–4Y for biological applications. ► Modified silane-treated Mg–4Y increased its corrosion resistance in both In Vitro and In Vivo environments. ► In Vitro testing environment is not consistent with In Vivo animal environment. ► The modified silane mixture protecting mechanisms and its biocompatibility were discussed. ► A novel three-electrode corrosion-monitoring probe was developed for realizing this work's In Vivo testing goals.

  10. Galvanic corrosion of beryllium welds

    International Nuclear Information System (INIS)

    Hill, M.A.; Butt, D.P.; Lillard, R.S.

    1997-01-01

    Beryllium is difficult to weld because it is highly susceptible to cracking. The most commonly used filler metal in beryllium welds is Al-12 wt.% Si. Beryllium has been successfully welded using Al-Si filler metal with more than 30 wt.% Al. This filler creates an aluminum-rich fusion zone with a low melting point that tends to backfill cracks. Drawbacks to adding a filler metal include a reduction in service temperature, a lowering of the tensile strength of the weld, and the possibility for galvanic corrosion to occur at the weld. To evaluate the degree of interaction between Be and Al-Si in an actual weld, sections from a mock beryllium weldment were exposed to 0.1 M Cl - solution. Results indicate that the galvanic couple between Be and the Al-Si weld material results in the cathodic protection of the weld and of the anodic dissolution of the bulk Be material. While the cathodic protection of Al is generally inefficient, the high anodic dissolution rate of the bulk Be during pitting corrosion combined with the insulating properties of the Be oxide afford some protection of the Al-Si weld material. Although dissolution of the Be precipitate in the weld material does occur, no corrosion of the Al-Si matrix was observed

  11. Corrosion of steel in concrete

    International Nuclear Information System (INIS)

    Preece, C.M.

    1982-10-01

    A comparative study has been made of those properties of Massiv and Standard cements which are considered to determine their ability to protect steel reinforcement from corroding. Saturated Massiv cement has a higher evaporabel water content, but a significantly finer pore structure than has saturated Standard cement. This fine structure resulted in an electrical resistivity ten times higher and chloride diffusivity ten times lower than those of Standard cement. Electrochemical measurements have shown that the passive current density of steel in Massiv mortar is higher than that of steel in Standard mortar, but the higher current should lead to a more rapid decrease in potential to a level at which neither chloride attack of hydrogen evolution will occur. Whereas steel in Standard mortar was found to be highly susceptible to crevice corrosion, no such attack has been observed in Massiv mortar. Moreover, the initiation of chloride induced corrosion and the subsequent rates of corrosion were both lower in Massiv mortar than in Standard mortar. Thus, it may be predicted that Massiv cement would provide greater protection for steel reinforcement in underground structures exposed to chloride containing ground water than would Standard cement. (author)

  12. Chemical cleaning, decontamination and corrosion

    International Nuclear Information System (INIS)

    Gadiyar, H.S.; Das Chintamani; Gaonkar, K.B.

    1991-01-01

    Chemical cleaning of process equipments and pipings in chemical/petrochemical industries is necessitated for improving operation, for preventing premature failures and for avoiding contamination. In developing a chemical formulation for cleaning equipments, the important aspects to be considered include (i) effective removal of corrosion products and scales, (ii) minimum corrosion of the base metal, (iii) easy to handle chemicals and (iv) economic viability. As on date, a wide variety of chemical formulations are available, many of them are either proprietory or patented. For evolving an effective formulation, knowledge of the oxides of various metals and alloys on the one hand and acid concentration, complexing agents and inhibitors to be incorporated on the other, is quite essential. Organic acids like citric acid, acetic acid and formic acid are more popular ones, often used with EDTA for effective removal of corrosion products from ferrous components. The report enumerates some of the concepts in developing effective formulations for chemical cleaning of carbon steel components and further, makes an attempt to suggest simple formulations to be developed for chemical decontamination. (author). 6 refs., 3 fi gs., 4 tabs

  13. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe[sub 3]Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000[degrees]C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  14. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

    Iron aluminides are being developed for use as structural materials and/or cladding alloys in fossil energy systems. Extensive development has been in progress on Fe{sub 3}Al-based alloys to improve the engineering ductility of these alloys. This paper describes results from the ongoing program to evaluate the corrosion performance of these alloys. The experimental program at Argonne National Laboratory involvesthermogravimetric analyses of alloys exposed to environments that simulate coal gasification and fluidized-bed combustion. Experiments were conducted at 650--1000{degrees}C in simulated oxygen/sulfur gas mixtures. In addition, oxidation/sulfidation behavior of several alumina-forming Fe-Al and Fe-Cr-Ni-Al alloys was determined for comparison with the corrosion rates obtained on iron aluminides. Other aspects of the program are corrosion evaluation of the aluminides in the presence of HC1-containing gases and in the presence of slag from a slogging gasifier. Results are used to establish threshold Al levels in the alloys for development of protective alumina scales. Thermal cycling tests are used to examine the spalling resistance of the scales.

  15. The Application of Mechanical-Chemical Corrosion Theory in Downhole Tubing CO2 Corrosion Research

    OpenAIRE

    Zhu, Peike; Yan, Wei; Deng, Liyu; Deng, Jingen

    2015-01-01

    Indoor simulating experiment is a main method for oil field CO2 corrosion research. Experimental parameters are very important for an accurate simulation. Based on the mechanical-chemical corrosion theory, the external load may be possible to accelerate the corrosion rate. However, the influence of N2 pressure on CO2 corrosion during the simulating experiment is negligible. Because the coupon stress induced by additional N2 pressure is very low, therefore, the N2 adding procedure can be cance...

  16. Tribo-corrosion of coatings: a review

    OpenAIRE

    Wood, R.J.K.

    2007-01-01

    This paper reviews the available literature relating to the emerging research into the performance of coatings under combined wear and corrosion conditions. Understanding how coatings perform under these tribo-corrosion conditions is essential if the service life of equipment is to be predicted and to allow service life to be extended. Therefore, the tribo-corrosion performance of coatings deposited by a variety of techniques is discussed and the main mechanisms associated with their degradat...

  17. Natural analogues of nuclear waste glass corrosion

    International Nuclear Information System (INIS)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-01

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses

  18. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

    Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

    1999-01-06

    This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information available on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.

  19. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

    The oxidation and hot corrosion of high temperature oxide dispersion strengthened (ODS) alloys are reviewed. The environmental resistance of such alloys are classified by oxide growth rate, oxide volatility, oxide spalling, and hot corrosion limitations. Also discussed are environmentally resistant coatings for ODS materials. It is concluded that ODS NiCrAl and FeCrAl alloys are highly oxidation and corrosion resistant and can probably be used uncoated.

  20. Recognition and Analysis of Corrosion Failure Mechanisms

    OpenAIRE

    Steven Suess

    2006-01-01

    Corrosion has a vast impact on the global and domestic economy, and currently incurs losses of nearly $300 billion annually to the U.S. economy alone. Because of the huge impact of corrosion, it is imperative to have a systematic approach to recognizing and mitigating corrosion problems as soon as possible after they become apparent. A proper failure analysis includes collection of pertinent background data and service history, followed by visual inspection, photographic documentation, materi...

  1. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  2. Optimising corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Thorarinsdottir, R.I.; Andersen, A.

    2002-01-01

    A three-year project - financially supported by the Nordic Industrial Fund - on monitoring of corrosion in district heating systems has been initiated with participation of researchers and industrial partners in Denmark, Finland, Iceland, Norway and Sweden. The primary objective of the project...... is to improve the quality control in district heating systems by corrosion monitoring. In Danish systems electrochemical impedance spectroscopy (EIS), linear polarisation resistance (LPR), high-sensitive electrical resistance (ER) technology, crevice corrosion probes, as well as weight loss coupons...

  3. Ferritic stainless steels: corrosion resistance + economy

    International Nuclear Information System (INIS)

    Remus, A.L.

    1976-01-01

    Ferritic stainless steels provide corrosion resistance at lower cost. They include Type 409, Type 439, 18SR, 20-Mo (1.6 Mo), 18-2 (2 Mo), 26-1S, E-Brite 26-1, 29 Cr-4 Mo, and 29 Cr-4 Mo-2 Ni. Their corrosion and mechanical properties are examined. Resistance to stress-corrosion cracking is an advantage compared to austenitic types

  4. The CLEM model: Path analysis of the mediating effects of attitudes and motivational beliefs on the relationship between perceived learning environment and course performance in an undergraduate nonmajor biology course

    Science.gov (United States)

    Partin, Matthew L.

    The problem addressed in this study stems from three crises currently faced by post-secondary science educators in the United States: relatively low scientific literacy among students entering college, the need for more students to pursue science related careers, and poor attitudes among students toward studying science. In this dissertation the following questions are addressed: Is there a relationship between students' perceptions of their learning environment and course performance, and what roles do motivation and attitudes play in mediating that relationship? This study also examines the effects of gender and ethnicity on motivation, attitudes, and course performance. The purpose of this study is to test a path model describing the mediating effects of motivation and attitudes on constructivist learning environments and course performance. The following study considers contemporary understanding of teaching and learning as well as motivation and attitudes to suggest a direction for future reform efforts and to guide post-secondary science education instructors and leaders in the design of constructivist learning environments for undergraduate nonmajor biology courses. This study concludes that, although the classroom learning environment has a small direct effect on course performance, there is a moderate total effect on self-efficacy and intrinsic goal orientation. The classroom learning environment also had a moderate indirect effect on attitudes toward biology. Furthermore, attitudes have a moderate direct effect on course performance and self-efficacy has a strong direct effect on both course performance and attitudes toward biology. Self-efficacy seems to be particularly important; however, each of these constructs is important in its own right and instructors in higher education should strive to enhance each of them among their students. If students are to learn using constructivist methods they need the proper motivation and positive attitudes to

  5. Colorimetric visualization of tin corrosion: A method for early stage corrosion detection on printed circuit boards

    DEFF Research Database (Denmark)

    Verdingovas, Vadimas; Jellesen, Morten Stendahl; Ambat, Rajan

    2017-01-01

    A majority of printed circuit board surfaces are covered with tin, therefore tin corrosion under humid conditions and movement of tin ions under the influence of an electric field plays an important role in the corrosion failure development. Tracking tin corrosion products spread on the printed...

  6. Corrosion problems and solutions in oil refining and petrochemical industry

    CERN Document Server

    Groysman, Alec

    2017-01-01

    This book addresses corrosion problems and their solutions at facilities in the oil refining and petrochemical industry, including cooling water and boiler feed water units. Further, it describes and analyzes corrosion control actions, corrosion monitoring, and corrosion management. Corrosion problems are a perennial issue in the oil refining and petrochemical industry, as they lead to a deterioration of the functional properties of metallic equipment and harm the environment – both of which need to be protected for the sake of current and future generations. Accordingly, this book examines and analyzes typical and atypical corrosion failure cases and their prevention at refineries and petrochemical facilities, including problems with: pipelines, tanks, furnaces, distillation columns, absorbers, heat exchangers, and pumps. In addition, it describes naphthenic acid corrosion, stress corrosion cracking, hydrogen damages, sulfidic corrosion, microbiologically induced corrosion, erosion-corrosion, and corrosion...

  7. Corrosion process studies in a nuclear waste container

    International Nuclear Information System (INIS)

    Guasp, Ruben A.; Lanzani, Liliana A.; Coronel, Pascual; Bruzzoni, Pablo; Semino, Carlos J.

    1999-01-01

    Latest results on corrosion behavior studies on high activity nuclear waste container are reported. Corrosion evaluation on lead base alloys and modeling to predict carbon steel external container cover generalized corrosion, are the main issues of these studies. (author)

  8. NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2004-12-01

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this proposed project is to develop a technology for on-line corrosion monitoring based on a new concept. This report describes the initial results from the first-year effort of the three-year study that include laboratory development and experiment, and pilot combustor testing.

  9. New corrosion issues in gas sweetening plants

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, R.G. (CLI International and Asperger Technologies, Houston, TX (United States))

    Gas treating plants are experiencing corrosion problems which impact on efficiency and safety. While general corrosion is not particularly hazardous in the gas processing industry, local corrosion is very dangerous since it has several different mechanisms, all of which have dangerously high rates, and it occurs at locations which are hard to find and hard to predict. A newly discovered, velocity-dependent type of corrosion is reported. It is related to yet-undefined species which cause excessively high corrosion in areas of turbulence. This accelerated corrosion is not due to erosion or cavitation, but to a diffusion-limited reaction accelerated by turbulence. A full-flow test loop was built to evaluate the corrosiveness of gas plant solutions at their normal temperature and flow rates. Test runs were conducted with Co[sub 2]-loaded amine solutions for periods of 12 days. Carbon steel specimens mounted in the test loop were examined and corrosion rates calculated. Chromium alloys were shown to be attacked by corrodents in the low-velocity part of the loop and very aggressively attacked in the high-velocity part. The tests demonstrate the need for rigorous monitoring of corrosion in areas of higher velocity such as piping elbows and other points of turbulence. 5 refs., 2 figs., 3 tabs.

  10. Corrosion probe. Innovative technology summary report

    International Nuclear Information System (INIS)

    1999-05-01

    Over 253 million liters of high-level waste (HLW) generated from plutonium production is stored in mild steel tanks at the Department of Energy (DOE) Hanford Site. Corrosion monitoring of double-shell storage tanks (DSTs) is currently performed at Hanford using a combination of process knowledge and tank waste sampling and analysis. Available technologies for corrosion monitoring have progressed to a point where it is feasible to monitor and control corrosion by on-line monitoring of the corrosion process and direct addition of corrosion inhibitors. The electrochemical noise (EN) technique deploys EN-based corrosion monitoring probes into storage tanks. This system is specifically designed to measure corrosion rates and detect changes in waste chemistry that trigger the onset of pitting and cracking. These on-line probes can determine whether additional corrosion inhibitor is required and, if so, provide information on an effective end point to the corrosion inhibitor addition procedure. This report describes the technology, its performance, its application, costs, regulatory and policy issues, and lessons learned

  11. Emerging Corrosion Inhibitors for Interfacial Coating

    Directory of Open Access Journals (Sweden)

    Mona Taghavikish

    2017-12-01

    Full Text Available Corrosion is a deterioration of a metal due to reaction with environment. The use of corrosion inhibitors is one of the most effective ways of protecting metal surfaces against corrosion. Their effectiveness is related to the chemical composition, their molecular structures and affinities for adsorption on the metal surface. This review focuses on the potential of ionic liquid, polyionic liquid (PIL and graphene as promising corrosion inhibitors in emerging coatings due to their remarkable properties and various embedment or fabrication strategies. The review begins with a precise description of the synthesis, characterization and structure-property-performance relationship of such inhibitors for anti-corrosion coatings. It establishes a platform for the formation of new generation of PIL based coatings and shows that PIL corrosion inhibitors with various heteroatoms in different form can be employed for corrosion protection with higher barrier properties and protection of metal surface. However, such study is still in its infancy and there is significant scope to further develop new structures of PIL based corrosion inhibitors and coatings and study their behaviour in protection of metals. Besides, it is identified that the combination of ionic liquid, PIL and graphene could possibly contribute to the development of the ultimate corrosion inhibitor based coating.

  12. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

    Full Text Available Fouling deposits on aluminum heat exchanger reduce the heat transfer efficiency and cause corrosion to the apparatus. This study focuses on the corrosive behavior of aluminum coupons covered with a layer of artificial fouling in a humid atmosphere by their weight loss, Tafel plots, electrochemical impedance spectroscopy (EIS, and scanning electron microscope (SEM observations. The results reveal that chloride is one of the major elements found in the fouling which damages the passive film and initiates corrosion. The galvanic corrosion between the metal and the adjacent carbon particles accelerates the corrosive process. Furthermore, the black carbon favors the moisture uptake, and gives the dissolved oxygen greater chance to migrate through the fouling layer and form a continuous diffusive path. The corrosion rate decreasing over time is conformed to electrochemistry measurements and can be verified by Faraday’s law. The EIS results indicate that the mechanism of corrosion can be interpreted by the pitting corrosion evolution mechanism, and that pitting was observed on the coupons by SEM after corrosive exposure.

  13. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

    Three candidate materials for construction of buffer tanks for district heating water have been tested for corrosion fatigue properties in a district heating water environment. The investigation included Slow Strain Rate Testing of plain tensile specimens, crack initiation testing by corrosion...... fatigue of plain tensile specimens and crack growth rate determination for Compact Tensile Specimens under corrosion fatigue conditions. The three materials are equal with respect to stress corrosion sensibility and crack initiation. Crack growth rate is increased with a factor of 4-6 relative to an inert...

  14. Factors Affecting Corrosion in Gulf of Finland Brackish Water

    Directory of Open Access Journals (Sweden)

    Jari Aromaa

    2016-01-01

    Full Text Available The Baltic Sea is a relatively shallow inland sea surrounded by the countries of North-Eastern Europe and Scandinavia. The brackish water in the Baltic Sea has low salt concentration and it is typically one-sixth of the ocean seawater. The “nominal” amount of dissolved solids, upon which formulae for artificial seawater are based, is about 34,500 ppm, of which most is sodium chloride. The major constituents are those whose concentrations are greater than 1 mg/L and are not greatly affected by biological processes. The ratio of concentrations of these ions and molecules to each other is relatively constant. Corrosion rates were determined in long-term tests in Gulf of Finland brackish water off Helsinki. The water temperature varies through the year from about 0°C in January to 15-16°C in June to August. Salinity is 4–6‰, highest at the end of summer and lowest when ice melts. pH is between 7.0 and 8.1. Weight loss tests from one- to four-year tests for steel, stainless steel, copper, aluminium, zinc, and galvanized steel are reported and compared to short term laboratory tests in artificial seawater. Tests for passivation rates and crevice corrosion for stainless steel are discussed in terms of environment variation. The effect of corrosion on strength of steel is also discussed.

  15. Mediated electrochemical oxidation of organic wastes using a Co(III) mediator in a neutral electrolyte

    International Nuclear Information System (INIS)

    Balazs, G.B.; Lewis, P.R.

    1999-01-01

    An electrochemical cell with a Co(III) mediator and neutral pH anolyte provides efficient destruction of organic and mixed wastes. The organic waste is concentrated in the anolyte reservoir, where the cobalt mediator oxidizes the organics and insoluble radioactive species and is regenerated at the anode until all organics are converted to carbon dioxide and destroyed. The neutral electrolyte is non-corrosive, and thus extends the lifetime of the cell and its components. 2 figs

  16. Corrosion '98: 53. annual conference and exposition, proceedings

    International Nuclear Information System (INIS)

    Anon.

    1998-01-01

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

  17. Assessing Level and Effectiveness of Corrosion Education in the UAE

    OpenAIRE

    Hwee Ling Lim

    2012-01-01

    The consequences of corrosion can be minimized by an engineering workforce well trained in corrosion fundamentals and management. Since the United Arab Emirates incurs the second highest cost of corrosion after Saudi Arabia, this paper examined the quality of corrosion education in the UAE. Surveys with academia and industry respondents showed that dedicated corrosion courses and engineering courses that integrated corrosion into the curricula were available in UAE universities, but graduates...

  18. Corrosion protection performance of corrosion inhibitors and epoxy-coated reinforcing steel in a simulated concrete pore water solution.

    Science.gov (United States)

    1998-06-01

    We used a simulated concrete pore water solution to evaluate the corrosion protection performance of concrete corrosion-inhibiting admixtures and epoxy-coated reinforcing bars (ECR). We evaluated three commercial corrosion inhibitors, ECR from three ...

  19. NASA's Corrosion Technology Laboratory at the Kennedy Space Center: Anticipating, Managing, and Preventing Corrosion

    Science.gov (United States)

    Calle, Luz Marina

    2014-01-01

    Corrosion is the degradation of a material that results from its interaction with the environment. The marine environment at NASAs Kennedy Space Center (KSC) has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the United States. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pads were rendered even more severe by the 70 tons of highly corrosive hydrochloric acid that were generated by the solid rocket boosters. Numerous failures at the launch pads are caused by corrosion.The structural integrity of ground infrastructure and flight hardware is critical to the success, safety, cost, and sustainability of space missions. As a result of fifty years of experience with launch and ground operations in a natural marine environment that is highly corrosive, NASAs Corrosion Technology Laboratory at KSC is a major source of corrosion control expertise in the launch and other environments. Throughout its history, the Laboratory has evolved from what started as an atmospheric exposure facility near NASAs launch pads into a world-wide recognized capability that provides technical innovations and engineering services in all areas of corrosion for NASA and external customers.This presentation will provide a historical overview of the role of NASAs Corrosion Technology in anticipating, managing, and preventing corrosion. One important challenge in managing and preventing corrosion involves the detrimental impact on humans and the environment of what have been very effective corrosion control strategies. This challenge has motivated the development of new corrosion control technologies that are more effective and environmentally friendly. Strategies for improved corrosion protection and durability can have a huge impact on the economic sustainability of human spaceflight operations.

  20. Technical note 4. Corrosion of copper canister

    International Nuclear Information System (INIS)

    Szakalos, Peter; Seetharaman, Seshadri

    2012-06-01

    Objectives of the project: In this review assignment, SKB's treatment of copper corrosion processes or mechanisms in SR-Site shall be reviewed both for the anticipated oxic and anoxic repository environments. The reviewer(s) shall consider if corrosion and corrosion mechanisms of the copper canisters in different possible evolutionary repository environments have been properly described. The objectives of this initial review phase in the area of copper corrosion is to achieve a broad coverage of SR-Site and its supporting references and in particular identify the need for complementary information and clarifications to be delivered by SKB. Summary by the authors: It is expected that the inflow of ground water to the deposition holes and tunnels in the Forsmark repository will be very slow. Thus, it might take some few hundred years up to thousand years before the deposition holes are filled with ground water and it might take 6000 years or more before the bentonite buffer is fully water saturated and pressurized. The copper canisters will therefore meet to two completely different environments: 1. An initial period of several hundreds of years when copper is exposed to gaseous corrosion. 2. And then to aqueous corrosion. From a corrosion point of view the first 1000 years are the most critical for the copper canister since pure, or phosphorus alloyed copper, is not designed to cope with corrosion at elevated temperatures. The outer copper surface temperature is expected to reach 100 deg C within some decades after closure of the repository and then slowly cool down to around 50 deg C after 1000 years. The gaseous corrosion is treated in SKB's safety assessment as being only dependent on oxygen gas and thus easily estimated by an oxygen mass-balance calculation. This simple model has no scientific support since several corrosive trace gases, such as sulphurous and nitrous compounds, operates together with water molecules (moisture) and the corrosion product consists

  1. Environmental Friendly Coatings & Corrosion Prevention for Flight Hardware

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives for this project are to identify, test, and develop qualification criteria for environmentally friendly corrosion protective coatings and corrosion...

  2. A rapid transition from ice covered CO2–rich waters to a biologically mediated CO2 sink in the eastern Weddell Gyre

    Directory of Open Access Journals (Sweden)

    W. Geibert

    2008-09-01

    Full Text Available Circumpolar Deep Water (CDW, locally called Warm Deep Water (WDW, enters the Weddell Gyre in the southeast, roughly at 25° E to 30° E. In December 2002 and January 2003 we studied the effect of entrainment of WDW on the fugacity of carbon dioxide (fCO2 and dissolved inorganic carbon (DIC in Weddell Sea surface waters. Ultimately the fCO2 difference across the sea surface drives air-sea fluxes of CO2. Deep CTD sections and surface transects of fCO2 were made along the Prime Meridian, a northwest-southeast section, and along 17° E to 23° E during cruise ANT XX/2 on FS Polarstern. Upward movement and entrainment of WDW into the winter mixed layer had significantly increased DIC and fCO2 below the sea ice along 0° W and 17° E to 23° E, notably in the southern Weddell Gyre. Nonetheless, the ice cover largely prevented outgassing of CO2 to the atmosphere. During and upon melting of the ice, biological activity rapidly reduced surface water fCO2 by up to 100 μatm, thus creating a sink for atmospheric CO2. Despite the tendency of the surfacing WDW to cause CO2 supersaturation, the Weddell Gyre may well be a CO2 sink on an annual basis due to this effective mechanism involving ice cover and ensuing biological fCO2 reduction. Dissolution of calcium carbonate (CaCO3 in melting sea ice may play a minor role in this rapid reduction of surface water fCO2.

  3. Corrosion behaviour of high copper dental amalgams.

    Science.gov (United States)

    Yap, A U J; Ng, B L; Blackwood, D J

    2004-06-01

    This study evaluated the corrosion behaviour of two high copper dental amalgam alloys [Dispersalloy (Dentsply-Caulk) and Tytin (Kerr)] in different electrolytes. Amalgam specimens were prepared, coupled to a copper wire, cemented into glass tubes and polished to a 600-grit finish. A corrosion cell was prepared using a carbon counter-electrode, a standard calomel electrode as the reference and amalgam as the working electrode. The alloys were tested in the following mediums at 37 degrees C: (i) artificial saliva based on Fusayama's solution (FS), (ii) artificial saliva with citric acid adjusted to pH 4.0 (FC) and (iii) 1% sodium chloride solution (SC). Corrosion potentials (E(corr)) and corrosion rates (I(corr)) were determined using potentiostatic and impedance spectroscopy methods. Data was subjected to anova/Scheffe's post hoc test at 0.05 significance level. For both alloys, the corrosion potential in FS was significantly greater than in SC. Corrosion potential of Tytin in FS and SC was also significantly greater than in FC. The corrosion rate of Dispersalloy in FC was significantly greater than in FS and SC. For Tytin, corrosion rate in SC was significantly greater than in FS and FC. Although no significant difference in corrosion potential/rate was observed between the alloys when tested in FS, significant differences were observed when electrochemical testing was carried out in FC and SC. The corrosion behaviour of high copper amalgam alloys are both material and environment dependent. Certain food substances may increase the corrosion of high copper amalgams.

  4. Real time corrosion monitoring in atmosphere using automated battery driven corrosion loggers

    DEFF Research Database (Denmark)

    Prosek, T.; Kouril, M.; Hilbert, Lisbeth Rischel

    2008-01-01

    diminishes due to corrosion. Zinc, iron, copper and nickel sensors at several thicknesses are available. Sensitivity of the corrosion measurement varies from 1 to 10 nm depending on the type and thickness of the sensor. Changes in the air corrosivity can be thus detected within hours or even tens of minutes....... The logger lifetime in medium corrosive environments is designed to be 2 years with full autonomy. Data on the sensor corrosion rate are available any time through GPRS connection or by a non-contact inductive reading without the need of retracting the logger from the exposure site....

  5. Penetration of corrosion products and corrosion-induced cracking in reinforced cementitious materials

    DEFF Research Database (Denmark)

    Michel, Alexander; Pease, Brad J.; Peterova, Adela

    2014-01-01

    -dependent concentrations of corrosion products averaged through the specimen thickness. Digital image correlation (DIC) was used to measure corrosion-induced deformations including deformations between steel and cementitious matrix as well as formation and propagation of corrosion-induced cracks. Based on experimental...... observations, a conceptual model was developed to describe the penetration of solid corrosion products into capillary pores of the cementitious matrix. Only capillary pores within a corrosion accommodating region (CAR), i.e. in close proximity of the steel reinforcement, were considered accessible...

  6. High Temperature Corrosion under Laboratory Conditions Simulating Biomass-Firing: A Comprehensive Characterization of Corrosion Products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2014-01-01

    characterization of the corrosion products. The corrosion products consisted of three layers: i) the outermost layer consisting of a mixed layer of K2SO4 and FexOy on a partly molten layer of the initial deposit, ii) the middle layer consists of spinel (FeCr2O4) and Fe2O3, and iii) the innermost layer is a sponge......-like Ni3S2 containing layer. At the corrosion front, Cl-rich protrusions were observed. Results indicate that selective corrosion of Fe and Cr by Cl, active oxidation and sulphidation attack of Ni are possible corrosion mechanisms....

  7. Stress Corrosion-Cracking and Corrosion Fatigue Impact of IZ-C17+ Zinc Nickel on 4340 Steel

    Science.gov (United States)

    2017-05-17

    corrosion, cracking, corrosion fatigue impact, zinc-nickel, steel , metallic coating 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT 18...REPORT NO: NAWCADPAX/TIM-2016/189 STRESS CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by...CORROSION-CRACKING AND CORROSION FATIGUE IMPACT OF IZ-C17+ ZINC-NICKEL ON 4340 STEEL by Craig Matzdorf Charles Lei Matt Stanley

  8. Discovery of Novel Bromophenol Hybrids as Potential Anticancer Agents through the Ros-Mediated Apoptotic Pathway: Design, Synthesis and Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Li-Jun Wang

    2017-11-01

    Full Text Available A series of bromophenol hybrids with N-containing heterocyclic moieties were designed, and their anticancer activities against a panel of five human cancer cell lines (A549, Bel7402, HepG2, HCT116 and Caco2 using MTT assay in vitro were explored. Among them, thirteen compounds (17a, 17b, 18a, 19a, 19b, 20a, 20b, 21a, 21b, 22a, 22b, 23a, and 23b exhibited significant inhibitory activity against the tested cancer cell lines. The structure-activity relationships (SARs of bromophenol derivatives were discussed. The promising candidate compound 17a could induce cell cycle arrest at G0/G1 phase and induce apoptosis in A549 cells, as well as caused DNA fragmentations, morphological changes and ROS generation by the mechanism studies. Furthermore, compound 17a suppression of Bcl-2 levels (decrease in the expression of the anti-apoptotic proteins Bcl-2 and down-regulation in the expression levels of Bcl-2 in A549 cells were observed, along with activation caspase-3 and PARP, which indicated that compound 17a induced A549 cells apoptosis in vitro through the ROS-mediated apoptotic pathway. These results might be useful for bromophenol derivatives to be explored and developed as novel anticancer drugs.

  9. Corrosion Behavior of New Cr-Ni-Cu Low Alloy Seawater Corrosion Resistant Steel

    Science.gov (United States)

    Zhang, Piaopiao; Yang, Zhongmin; Chen, Ying; Wang, Huimin

    Two kinds of Cr-Ni-Cu low alloyed steels were designed, 0.1%C-0.7%Cr-1.2%Ni-0.7Cu and 0.1%C-0.7%Cr-0.3%Ni-0.5Cu. With the method of SEM, XRD and electrochemical analysis and testing technology, periodic immersion accelerated corrosion test was carried out to investigate the corrosion resistance of the designed steels in simulated marine environment. The steel with best corrosion resistance was selected, and then focused on the variation of its corrosion rate with time. The results indicated that the designed Cu-Cr-Ni low alloyed steels showed better corrosion resistance than 20MnSi, the ratio of their corrosion rates was 0.44. The corrosion rate of designed steels decreased gradually to 3 4 g/(mm2·h) with the elongation of test period, while the corrosion rate of 20MnSi kept downward trend, not reach stability, and the corrosion rate gap between them became smaller. The Cr element banding enriched in the inner rust can withstand the diffusion of Cl-. Besides, the addition of Ni raised the self-corrosion potential of the bare steels and promoted the transformation of γ-FeOOH to α-FeOOH, and consequently, improved the stability of the rust and the corrosion resistance of steels.

  10. Surface morphology and corrosion resistance of electrodeposited ...

    Indian Academy of Sciences (India)

    Electrochemical corrosion resistance investigations were carried out in 5 M KOH, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found, that the composite coatings containing thiophene are more corrosion resistant in alkaline solution than the ...

  11. Microbiologically influenced corrosion in ship ballast tanks

    NARCIS (Netherlands)

    Heyer, A.

    2013-01-01

    Microbiologically influenced corrosion (MIC) is known to be a dangerous process in ship tanks due to its rapid and yet unpredictable occurrence, leading to extremely fast local corrosion, possibly jeopardizing the structural integrity, in a relatively short time. This project focuses on a

  12. Corrosion effects on soda lime glass

    NARCIS (Netherlands)

    Veer, F.A.; Rodichev, Y.M.

    2010-01-01

    Although soda lime glass is the most common used transparent material in architecture, little is known about the corrosion effects on long term strength and the interaction between corrosion and defects. Extensive testing on soda lime bars under different environmental conditions and different

  13. Glove corrosive liquid immersion and permeability study

    International Nuclear Information System (INIS)

    Middleton, H.W.

    1977-01-01

    The Occupational Safety and Health Administration's requirement for protective equipment for personnel working with chemical hazards resulted in a study of gloves used in work with corrosive liquids. Gloves of different materials and weights were tested using ASTM methods, in various corrosive liquids. Results show the best material for gloves used for different lengths of time in the liquids

  14. Corrosion comparisons between zirconium and titanium

    International Nuclear Information System (INIS)

    Yau Telin

    1992-01-01

    Zirconium and titanium are regarded as sister metals with excellent resistance to many corrosives. While these metals exhibit some similar corrosion properties, this paper discusses several major differences. The differences are found in chloride-free acids, acidic chloride solutions, salt solutions, alkaline solutions and organics. They are caused by the differences between the protective oxide films of zirconium and titanium. (orig.) [de

  15. INVESTIGATIONS ON THE CORROSION OF CONSTRUCTIONAL ...

    African Journals Online (AJOL)

    BCSE

    Results indicate that S355 and S235 steels have comparable corrosion resistance, which are much lower than that of S275. KEY WORDS: Corrosion, Steel, Salt spray, Tafel polarization, Electrochemical impedance spectroscopy. INTRODUCTION. Steel is an alloy used in construction and mechanical engineering.

  16. Computer-Aided Corrosion Program Management

    Science.gov (United States)

    MacDowell, Louis

    2010-01-01

    This viewgraph presentation reviews Computer-Aided Corrosion Program Management at John F. Kennedy Space Center. The contents include: 1) Corrosion at the Kennedy Space Center (KSC); 2) Requirements and Objectives; 3) Program Description, Background and History; 4) Approach and Implementation; 5) Challenges; 6) Lessons Learned; 7) Successes and Benefits; and 8) Summary and Conclusions.

  17. Internal Corrosion Detection in Liquids Pipelines

    Science.gov (United States)

    2012-01-01

    PHMSA project DTRS56-05-T-0005 "Development of ICDA for Liquid Petroleum Pipelines" led to the development of a Direct Assessment (DA) protocol to prioritize locations of possible internal corrosion. The underlying basis LP-ICDA is simple; corrosion ...

  18. A Course in Electrochemical and Corrosion Engineering.

    Science.gov (United States)

    Van Zee, John

    1985-01-01

    Describes a course designed to show similarities between electrochemistry and corrosion engineering and to show graduate students that electrochemical and corrosion engineering can be accomplished by extending their knowledge of chemical engineering models. Includes course outline, textbooks selected, and teaching methods used. (JN)

  19. Airway Complications following ingestion of corrosive | Ezike ...

    African Journals Online (AJOL)

    Conclusions: Corrosive ingestion is a major health problem in our environment. The proximal third of the oesophagus and the upper airway are mostly affected. These frequently result in life threatening airway complications demanding urgent tracheostomy. Key words: Corrosives, Burns, Airway, Respiratory distress.

  20. Dissolution properties of cerium dibutylphosphate corrosion inhibitors

    NARCIS (Netherlands)

    Soestbergen, M. van; Erich, S.J.F.; Huinink, H.P.; Adan, O.C.G.

    2013-01-01

    The corrosion inhibitor cerium dibutylphosphate, Ce(dbp)3, prevents corrosion by cerium and dbp deposition at the alkaline cathode and acidic anode respectively. The pH dependent Ce(dbp)3 solubility seems to play an essential role in the inhibition degree. We found that Ce(dbp) 3 scarcely dissolves

  1. Vibrational Spectroscopy in Studies of Atmospheric Corrosion.

    Science.gov (United States)

    Hosseinpour, Saman; Johnson, Magnus

    2017-04-18

    Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm.

  2. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Saman Hosseinpour

    2017-04-01

    Full Text Available Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm.

  3. Corrosion and compatibility in liquid alkali metals

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    The literature dealing with liquid alkali metal corrosion of vanadium and its alloys is reviewed in the following subsections. Attention is given to both lithium and sodium data. Preceding this review, a brief outline of the current state of understanding of liquid metal corrosion mechanisms is provided

  4. Erosion–corrosion and corrosion properties of DLC coated low temperature Erosion–corrosion and corrosion properties of DLC coated low temperature

    DEFF Research Database (Denmark)

    Jellesen, Morten Stendahl; Christiansen, Thomas; Hilbert, Lisbeth Rischel

    2009-01-01

    of AISI 316 as substrate for DLC coatings are investigated. Corrosion and erosion–corrosion measurements were carried out on low temperature nitrided stainless steel AISI 316 and on low temperature nitrided stainless steel AISI 316 with a top layer of DLC. The combination of DLC and low temperature...

  5. Factors affecting the corrosivity of pulping liquors

    Science.gov (United States)

    Hazlewood, Patrick Evan

    Increased equipment failures and the resultant increase in unplanned downtime as the result of process optimization programs continue to plague pulp mills. The failures are a result of a lack of understanding of corrosion in the different pulping liquors, specifically the parameters responsible for its adjustment such as the role and identification of inorganic and organic species. The current work investigates the role of inorganic species, namely sodium hydroxide and sodium sulfide, on liquor corrosivity at a range of process conditions beyond those currently experienced in literature. The role of sulfur species, in the activation of corrosion and the ability of hydroxide to passivate carbon steel A516-Gr70, is evaluated with gravimetric and electrochemical methods. The impact of wood chip weathering on process corrosion was also evaluated. Results were used to identify black liquor components, depending on the wood species, which play a significant role in the activation and inhibition of corrosion for carbon steel A516-Gr70 process equipment. Further, the effect of black liquor oxidation on liquor corrosivity was evaluated. Corrosion and stress corrosion cracking performance of selected materials provided information on classes of materials that may be reliably used in aggressive pulping environments.

  6. Geothermal drill pipe corrosion test plan

    Energy Technology Data Exchange (ETDEWEB)

    Caskey, B.C.; Copass, K.S.

    1980-12-01

    Plans are presented for conducting a field test of drill pipe corrosion, comparing air and nitrogen as drilling fluids. This test will provide data for evaluating the potential of reducing geothermal well drilling costs by extending drill pipe life and reducing corrosion control costs. The 10-day test will take place during fall 1980 at the Baca Location in Sandoval County, New Mexico.

  7. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-04-11

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

  8. Electrochemical corrosion measurements on noble electrodeposits

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1998-01-01

    Novel electrodeposits are compared with hard chrome and electroless Ni-P with respect to production, corrosion resistance and hardness.......Novel electrodeposits are compared with hard chrome and electroless Ni-P with respect to production, corrosion resistance and hardness....

  9. A South African corrosion research contribution

    International Nuclear Information System (INIS)

    Robinson, F.P.A.

    1980-01-01

    This paper contains the historical background to the setting up of the S.A. Corrosion Institute. The Metallurgy Department of the University of the Witwatersrand has been a training ground for corrosion scientists and engineers. Most of the research and development carried out has been devoted to stainless steels and more particularly to studying the effects of different alloying elements

  10. Silicate glasses corrosion. Texture analysis of the corrosion layer

    International Nuclear Information System (INIS)

    Portal, Sabine

    2001-01-01

    We have studied the kinetic and the texture evolution of the corroded layer that forms on glass surfaces exposed to acidic solutions. The corroded layer is depleted in alkali cations and is produced by an ion exchange mechanism. It is porous and shows a lower refractive index than the one of the bulk glass. Spectroscopic ellipsometry allows determining the thickness of the layer and its refractive index. Several other techniques have been developed for characterizing the corrosion behaviour of glass surfaces: porosity is thus investigated by adsorption-desorption of nitrogen; the thickness and the composition of the layer are studied by secondary ion mass spectroscopy (S.I.M.S.); sodium concentration in the solution has been analyzed by atomic absorption. This study shows the importance of leaching conditions and glass preparation. The type of drying employed is susceptible to modify the texture and the structure of the layer. The layers produced in the early stages of the leaching process are not easily detectable. The different results lead however to the same conclusion: after a strong increase of porosity, a densification of the layer is observed with increasing time. The evolution of the layer texture could therefore modify the kinetic of the glass corrosion. (author) [fr

  11. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. General Corrosion and Localized Corrosion of the Drip Shield

    International Nuclear Information System (INIS)

    Hua, F.; Mon, K.

    2003-01-01

    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

  13. Galvanic corrosion in odontological alloys

    International Nuclear Information System (INIS)

    Riesgo, O.; Bianchi, G.L.; Duffo, G.S.

    1993-01-01

    Galvanic corrosion can occur when different alloys are placed in direct contact within the oral cavity or within tissues. Concern has been expressed associated with the coupling of selected restorative materials as well as implant material with various alloys used for restorative procedures. This could be critical if the crown or bridge had subgingival finish line with a metallic zone in contact with the tissue, and the implant was made in titanium alloy. The present work shows the results of galvanic coupling studies done on implants of titanium alloy connected to nickel-chromium and cobalt-chromium alloys. (Author)

  14. A corrosive resistant heat exchanger

    Science.gov (United States)

    Richlen, S.L.

    1987-08-10

    A corrosive and erosive 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 pumped 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. 3 figs., 3 tabs.

  15. CORROSION RATE OF STEELS DX51D AND S220GD IN DIFFERENT CORROSION ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Alina Crina CIUBOTARIU

    2016-06-01

    Full Text Available Corrosion in the marine environment is an important issue because the costs causes by marine corrosion increased year upon year. It is necessary a correctly approach to materials selection, protection and corrosion control to reduce this burden of wasted materials, wasted energy and wasted money. Many different types of corrosion attack can be observed to structures, ships and other equipment used in sea water service. Shipping containers are exposed to various corrosive mediums like as airborne salt, industrial pollutants, rain and saltwater. Transport damage during loading onto and unloading off trucks, train beds and ships breaches the paint coating which further contributes to corrosion. The result is shortened container life and high costs for container repair or replacement. The paper intends to evaluate, by gravimetric method, the corrosion rate and corrosion penetration rate of two types of carbon steel DX51D and S220GD. Carbon steel DX51D and hot-dip galvanized steel S220GD are used in marine and industrial applications for buildings cargo vessels, container ships and oil tankers. For testing it was used different corrosive environments: 5% NaOH solution; 5% HCL solution and 0.5M NaCl solution. The samples were immersed in 400mL of testing solution for exposure period of 28 days. Periodically at 3 days, 7 days, 14 days, 21 days and 28 days was measured de mass loss and evaluate the corrosion rate and corrosion stability coefficient. The steel DX51D was stable in 5% NaOH solution for 28 days, the values of corrosion stability coefficient was 7 after 3 days and 6 after 28 days of immersion in corrosive medium. In 5% HCL solution steels DX51D and S220GD was completely corroded in 21 days with a corrosion stability coefficient equal with 9 for 7 days and 8 for 21 days of immersion in corrosive solution. It was observed a good resistance for 3 days in 0.5M NaCl solution with a corrosion stability coefficient equal with 5, but after that

  16. Launch Pad Coatings for Smart Corrosion Control

    Science.gov (United States)

    Calle, Luz M.; Hintze, Paul E.; Bucherl, Cori N.; Li, Wenyan; Buhrow, Jerry W.; Curran, Jerome P.; Whitten, Mary C.

    2010-01-01

    Corrosion is the degradation of a material as a result of its interaction with the environment. The environment at the KSC launch pads has been documented by ASM International (formerly American Society for Metals) as the most corrosive in the US. The 70 tons of highly corrosive hydrochloric acid that are generated by the solid rocket boosters during a launch exacerbate the corrosiveness of the environment at the pads. Numerous failures at the pads are caused by the pitting of stainless steels, rebar corrosion, and the degradation of concrete. Corrosion control of launch pad structures relies on the use of coatings selected from the qualified products list (QPL) of the NASA Standard 5008A for Protective Coating of Carbon Steel, Stainless Steel, and Aluminum on Launch Structures, Facilities, and Ground Support Equipment. This standard was developed to establish uniform engineering practices and methods and to ensure the inclusion of essential criteria in the coating of ground support equipment (GSE) and facilities used by or for NASA. This standard is applicable to GSE and facilities that support space vehicle or payload programs or projects and to critical facilities at all NASA locations worldwide. Environmental regulation changes have dramatically reduced the production, handling, use, and availability of conventional protective coatings for application to KSC launch structures and ground support equipment. Current attrition rate of qualified KSC coatings will drastically limit the number of commercial off the shelf (COTS) products available for the Constellation Program (CxP) ground operations (GO). CxP GO identified corrosion detection and control technologies as a critical, initial capability technology need for ground processing of Ares I and Ares V to meet Constellation Architecture Requirements Document (CARD) CxP 70000 operability requirements for reduced ground processing complexity, streamlined integrated testing, and operations phase affordability

  17. Steam generator corrosion 2007; Dampferzeugerkorrosion 2007

    Energy Technology Data Exchange (ETDEWEB)

    Born, M. (ed.)

    2007-07-01

    Between 8th and 9th November, 2007, SAXONIA Standortentwicklungs- und -verwertungsgesellschaft GmbH (Freiberg, Federal Republic of Germany) performed the 3rd Freiberger discussion conference ''Fireside boiler corrosion''. The topics of the lectures are: (a) Steam generator corrosion - an infinite history (Franz W. Alvert); (b) CFD computations for thermal waste treatment plants - a contribution for the damage recognition and remedy (Klaus Goerner, Thomas Klasen); (c) Experiences with the use of corrosion probes (Siegfried R. Horn, Ferdinand Haider, Barbara Waldmann, Ragnar Warnecke); (d) Use of additives for the limitation of the high temperature chlorine corrosion as an option apart from other measures to the corrosion protection (Wolfgang Spiegel); (e) Current research results and aims of research with respect to chlorine corrosion (Ragnar Warnecke); (f) Systematics of the corrosion phenomena - notes for the enterprise and corrosion protection (Thomas Herzog, Wolfgang Spiegel, Werner Schmidl); (g) Corrosion protection by cladding in steam generators of waste incinerators (Joerg Metschke); (h) Corrosion protection and wear protection by means of thermal spraying in steam generators (Dietmar Bendix); (i) Review of thick film nickelized components as an effective protection against high-temperature corrosion (Johann-Wilhelm Ansey); (j) Fireproof materials for waste incinerators - characteristics and profile of requirement (Johannes Imle); (k) Service life-relevant aspects of fireproof linings in the thermal recycling of waste (Till Osthoevener and Wolfgang Kollenberg); (l) Alternatives to the fireproof material in the heating space (Heino Sinn); (m) Cladding: Inconal 625 contra 686 - Fundamentals / applications in boiler construction and plant construction (Wolfgang Hoffmeister); (n) Thin films as efficient corrosion barriers - thermal spray coating in waste incinerators and biomass firing (Ruediger W. Schuelein, Steffen Hoehne, Friedrich

  18. Fuel corrosion processes under waste disposal conditions

    International Nuclear Information System (INIS)

    Shoesmith, D.W.

    1999-09-01

    Under the oxidizing conditions likely to be encountered in the Yucca Mountain Repository, fuel dissolution is a corrosion process involving the coupling of the anodic dissolution of the fuel with the cathodic reduction of oxidants available within the repository. The oxidants potentially available to drive fuel corrosion are environmental oxygen, supplied by the transport through the permeable rock of the mountain and molecular and radical species produced by the radiolysis of available aerated water. The mechanism of these coupled anodic and cathodic reactions is reviewed in detail. While gaps in understanding remain, many kinetic features of these reactions have been studied in considerable detail, and a reasonably justified mechanism for fuel corrosion is available. The corrosion rate is determined primarily by environmental factors rather than the properties of the fuel. Thus, with the exception of increase in rate due to an increase in surface area, pre-oxidation of the fuel has little effect on the corrosion rate

  19. Stress corrosion of low alloy steel forgings

    International Nuclear Information System (INIS)

    Thornton, D.V.; Mould, P.B.; Patrick, E.C.

    1976-01-01

    The catastrophic failure of a steam turbine rotor disc at Hinkley Point 'A' Power station was shown to have been caused by the growth of a stress corrosion crack to critical dimensions. This failure has promoted great interest in the stress corrosion susceptibility of medium strength low alloy steel forgings in steam environments. Consequently, initiation and growth of stress corrosion cracks of typical disc steels have been investigated in steam and also in water at 95 0 C. Cracking has been shown to occur, predominantly in an intergranular manner, with growth rates of between 10 -9 and 10 -7 mm sec. -1 . It is observed that corrosion pitting and oxide penetration prior to the establishment of a stress corrosion crack in the plain samples. (author)

  20. Water side corrosion prevention in boilers

    International Nuclear Information System (INIS)

    Zeid, A.

    1993-01-01

    Corrosion may be defined as a naturally occurring physical and chemical deterioration of a material due to reaction with the environment or surrounding atmosphere. In boilers the material is subjected on both sides to two different media which may cause severe corrosion. At the water side the content of O 2 considered one of the principal factors which determine the extent of corrosion in the boiler tubes. This paper deals with certain conditions that result in the increase of O 2 in the boiler water and hence increase the corrosion rate, to minimize the effect of these conditions a chemical treatment was carried out the results obtained indicated the success of the treatment procedure in corrosion prevention and boiler material protection. The treatment is traditional. But the study indicates how a simple mean could be applied to solve a serious problem. 4 tab

  1. Corrosion surveillance in spent fuel storage pools

    International Nuclear Information System (INIS)

    Howell, J.P.

    1996-01-01

    In mid-1991, corrosion of aluminum-clad spent nuclear fuel was observed in the light-water filled basins at the Savannah River site. A corrosion surveillance program was initiated in the P, K, L-Reactor basins and in the Receiving Basin for Offsite Fuels (RBOF). This program verified the aggressive nature of the pitting corrosion and provided recommendations for changes in basin operations to permit extended longer term interim storage. The changes were implemented during 1994--1996 and have resulted in significantly improved basin water quality with conductivity in the 1--3 microS/cm range. Under these improved conditions, no new pitting has been observed over the last three years. This paper describes the corrosion surveillance program at SRS and what has been learned about the corrosion of aluminum-clad in spent fuel storage pools

  2. Modeling of Corrosion-induced Concrete Damage

    DEFF Research Database (Denmark)

    Thybo, Anna Emilie A.; Michel, Alexander; Stang, Henrik

    2013-01-01

    In the present paper a finite element model is introduced to simulate corrosion-induced damage in concrete. The model takes into account the penetration of corrosion products into the concrete as well as non-uniform formation of corrosion products around the reinforcement. To ac-count for the non......-uniform formation of corrosion products at the concrete/reinforcement interface, a deterministic approach is used. The model gives good estimates of both deformations in the con-crete/reinforcement interface and crack width when compared to experimental data. Further, it is shown that non-uniform deposition...... of corrosion products affects both the time-to cover cracking and the crack width at the concrete surface....

  3. Inhibition of aluminum corrosion using Opuntia extract

    Energy Technology Data Exchange (ETDEWEB)

    El-Etre, A.Y

    2003-11-01

    The inhibitive action of the mucilage extracted from the modified stems of prickly pears, toward acid corrosion of aluminum, is tested using weight loss, thermometry, hydrogen evolution and polarization techniques. It was found that the extract acts as a good corrosion inhibitor for aluminum corrosion in 2.0 M HCl solution. The inhibition action of the extract was discussed in view of Langmuir adsorption isotherm. It was found that the adsorption of the extract on aluminum surface is a spontaneous process. The inhibition efficiency (IE) increases as the extract concentration is increased. The effect of temperature on the IE was studied. It was found that the presence of extract increases the activation energy of the corrosion reaction. Moreover, the thermodynamic parameters of the adsorption process were calculated. It was found also that the Opuntia extract provides a good protection to aluminum against pitting corrosion in chloride ion containing solutions.

  4. Corrosion study in molten fluoride salt

    International Nuclear Information System (INIS)

    Keny, S.J.; Kumbhar, A.G.; Rangarajan, S.; Gupta, V.K.; Maheshwari, N.K.; Vijayan, P.K.

    2013-01-01

    Corrosion behaviors of two alloys viz. Inconel 625 and Inconel 617 were tested in molten fluoride salts of lithium, sodium and potassium (FLiNaK) in the temperature range of 550-750 ℃ in a nickel lined Inconel vessel. Electrochemical polarization (Tafel plot) technique was used for this purpose. For both alloys, the corrosion rate was found to increase sharply beyond 650 ℃ . At 600 ℃ , Inconel 625 showed a decreasing trend in the corrosion rate over a period of 24 hours, probably due to changes in the surface conditions. After fifteen days, re-testing of Inconel 625 in the same melt showed an increase in the corrosion rate. Inconel 625 was found to be more corrosion resistant than Inconel 617. (author)

  5. Passive Corrosion Behavior of Alloy 22

    International Nuclear Information System (INIS)

    R.B. Rebak; J.H. Payer

    2006-01-01

    Alloy 22 (NO6022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nano-meters per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids

  6. Microencapsulation Technologies for Corrosion Protective Coating Applications

    Science.gov (United States)

    Li, Wenyan; Buhrow, Jerry; Jolley, Scott; Calle, Luz; Pearman, Benjamin; Zhang, Xuejun

    2015-01-01

    Microencapsulation technologies for functional smart Coatings for autonomous corrosion control have been a research area of strong emphasis during the last decade. This work concerns the development of pH sensitive micro-containers (microparticles and microcapsules) for autonomous corrosion control. This paper presents an overview of the state-of-the-art in the field of microencapsulation for corrosion control applications, as well as the technical details of the pH sensitive microcontainer approach, such as selection criteria for corrosion indicators and corrosion inhibitors; the development and optimization of encapsulation methods; function evaluation before and after incorporation of the microcontainers into coatings; and further optimization to improve coating compatibility and performance.

  7. Corrosion protection with eco-friendly inhibitors

    International Nuclear Information System (INIS)

    Shahid, Muhammad

    2011-01-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO 3 −2 and NO −3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10 −4  M; 93% efficiency was exhibited at this concentration. (review)

  8. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

    Corrosion occurs as a result of the interaction of a metal with its environment. The extent of corrosion depends on the type of metal, the existing conditions in the environment and the type of aggressive ions present in the medium. For example, CO3-2 and NO-3 produce an insoluble deposit on the surface of iron, resulting in the isolation of metal and consequent decrease of corrosion. On the other hand, halide ions are adsorbed selectively on the metal surface and prevent formation of the oxide phase on the metal surface, resulting in continuous corrosion. Iron, aluminum and their alloys are widely used, both domestically and industrially. Linear alkylbenzene and linear alkylbenzene sulfonate are commonly used as detergents. They have also been found together in waste water. It is claimed that these chemicals act as inhibitors for stainless steel and aluminum. Release of toxic gases as a result of corrosion in pipelines may lead in certain cases to air pollution and possible health hazards. Therefore, there are two ways to look at the relationship between corrosion and pollution: (i) corrosion of metals and alloys due to environmental pollution and (ii) environmental pollution as a result of corrosion protection. This paper encompasses the two scenarios and possible remedies for various cases, using 'green' inhibitors obtained either from plant extracts or from pharmaceutical compounds. In the present study, the effect of piperacillin sodium as a corrosion inhibitor for mild steel was investigated using a weight-loss method as well as a three-electrode dc electrochemical technique. It was found that the corrosion rate decreased as the concentration of the inhibitor increased up to 9×10-4 M 93% efficiency was exhibited at this concentration.

  9. Novel ciprofloxacin hybrids using biology oriented drug synthesis (BIODS) approach: Anticancer activity, effects on cell cycle profile, caspase-3 mediated apoptosis, topoisomerase II inhibition, and antibacterial activity.

    Science.gov (United States)

    Kassab, Asmaa E; Gedawy, Ehab M

    2018-03-09

    As we are interested in synthetizing biologically active leads with dual anticancer and antibacterial activity, we adopted biology oriented drug synthesis (BIODS) strategy to synthesize a series of novel ciprofloxacin (CP) hybrids. The National Cancer Institute (USA) selected seventeen newly synthesized compounds for anticancer evaluation against 59 different human tumor cell lines. Five compounds 3e, 3f, 3h, 3o and 3p were further studied through determination of IC 50 values against the most sensitive cancer cell lines. In vitro results showed that the five compounds exhibited potent anticancer activity against test cell lines in nanomolar to micromolar range, with IC 50 values between 0.72 and 4.92 μM, which was 9 to1.5 folds more potent than doxorubicin. In this study, two promising potent anticancer CP hybrids, 3f and 3o, were identified. The anti-proliferative activity of these compounds appears to correlate well with their ability to inhibit Topo II (IC 50  = 0.58 and 0.86 μM). It is worth mentioning that compound 3f was 6 folds more potent than doxorubicin, 5 folds more potent than amsacrine and 1.5 folds more potent than etoposide. At the same time, compound 3o showed 4 folds more inhibitory activity against Topo II than doxorubicin, 3 folds more potent than amsacrine and almost equipotent activity to etoposide. Activation of damage response pathway of the DNA leads to cell cycle arrest at G2/M phase, accumulation of cells in pre-G1 phase and annexin-V and propidium iodide staining, indicating that cell death proceeds through an apoptotic mechanism. Moreover, compounds 3f and 3o showed potent pro-apoptotic effect through induction of the intrinsic mitochondrial pathway of apoptosis. This mechanistic pathway was confirmed by a significant increase in the level of active caspase-3 compared to control. This observation may indicate that both CP hybrids can chelate with zinc, a powerful inhibitor of procaspase-3 enzymatic activity, so procaspase-3

  10. NUTRITIONAL THERAPY IN THE TREATMENT OF ACUTE CORROSIVE INTOXICATION IN ADULTS

    Science.gov (United States)

    Chibishev, Andon; Markoski, Velo; Smokovski, Ivica; Shikole, Emilija; Stevcevska, Aleksandra

    2016-01-01

    Introduction: Acute intoxications with corrosive substances can cause severe chemical injuries of the upper gastrointestinal tract, most often located in the mouth, pharynx, esophagus, stomach and duodenum. If a patient survives the acute phase of intoxication, regenerative response may result in esophageal and/or gastric stenosis, and increased risk of esophageal and gastric cancer. Such intoxication may be fatal due to perforation or tracheal necrosis. Enteral nutrition is a nutritional method when nutritional substances are administered through specially designed tubing placed through the nose or percutaneously, directly into the GIT. Aim: The aim of this study is to describe the methods of artificial nutrition in patients with acute corrosive intoxications and the importance of nutritional support in the treatment of these intoxications. Discussion: Nutrition in the treatment of acute corrosive intoxications is one of the most important therapeutic processes that largely contribute to faster recovery of the post-corrosive injuries of upper GIT, stabilization of biologic, immunologic and metabolic parameters, and reduction of length of stay in hospital Aim of the treatment of acute corrosive intoxications is to prevent perforation and progressive fibrosis, and esophageal and gastric stenosis. There are different and often conflicting positions, on the conservative treatment of acute corrosive intoxications in adults. Such treatment mainly consists of anti-secretory treatment, antibiotics and intensive hyper-alimentation, aiming to prevent late post-corrosive intoxications. Conclusion: It is considered that nutritional support plays a major role in maintenance of metabolic processes and prevention of severe metabolic complications that could additionally aggravate the condition and impair the treatment. PMID:27047272

  11. Corrosion of circulating water pipings in thermal and nuclear power stations and corrosion prevention measures

    International Nuclear Information System (INIS)

    Hachiya, Minoru

    1982-01-01

    In the age of energy conservation at present, the power generation facilities have been examined from the viewpoint of performance, endurance and economy, and in particular, the prevention of the loss due to the corrosion of various facilities is one of most important problems. Since circulating water pipings are in contact with sea water and soil, the peculiar corrosion phenomena are brought about on their external and internal surfaces. Namely, the pitting corrosion due to the environment of soil quality difference, the defects of coating and the contact with reinforcing bars in concrete occurs on the external surface, and the overall corrosion due to the increase of flow velocity and the pitting corrosion due to the defects of coating, the contact with different kinds of metals and the gap in corrosion-resistant steel occur on the internal surface. As the measures for corrosion prevention, corrosion-preventive coating and electric corrosion prevention are applied. The principle, the potential and current density, the system, the design procedure and the examples of application of electric corrosion prevention are described. (Kako, I.)

  12. Pipeline corrosion prevention by pH stabilization or corrosion inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Nyborg, Rolf [Institute for Energy Technology, Oslo (Norway)

    2009-07-01

    In many offshore oil and gas projects the pipeline costs are a considerable part of the investment and can become prohibitively high if the corrosivity of the fluid necessitates the use of corrosion resistant alloys instead of carbon steel. Development of more robust and reliable methods for internal corrosion control can increase the application range of carbon steel and therefore have a large economic impact. Corrosion control of carbon steel pipelines has traditionally often been managed by the use of corrosion inhibitors. The pH stabilization technique has been successfully used for corrosion control of several large wet gas pipelines in the last years. This method has advantages over film forming corrosion inhibitors when no or little formation water is produced. The use of corrosion inhibitors in multiphase pipelines implies several challenges which are not fully accounted for in traditional corrosion inhibitor testing procedures. Specialized test procedures have been developed to take account for the presence of emulsions dispersions and sand and clay particles in corrosion inhibitor testing. (author)

  13. Establishment of Cre-mediated HBV recombinant cccDNA (rcccDNA) cell line for cccDNA biology and antiviral screening assays.

    Science.gov (United States)

    Wu, Min; Li, Jin; Yue, Lei; Bai, Lu; Li, Yaming; Chen, Jieliang; Zhang, Xiaonan; Yuan, Zhenghong

    2018-04-01

    Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA), existing in hepatocyte nuclei as a stable minichromosome, plays a central role in the life cycle of the virus and permits the persistence of infection. Despite being essential for HBV infection, little is known about the molecular mechanisms of cccDNA formation, regulation and degradation, and there is no therapeutic agents directly targeting cccDNA, fore mostly due to the lack of robust, reliable and quantifiable HBV cccDNA models. In this study, combined the Cre/loxP and sleeping beauty transposons system, we established HepG2-derived cell lines integrated with 2-60 copies of monomeric HBV genome flanked by loxP sites (HepG2-HBV/loxP). After Cre expression via adenoviral transduction, 3.3-kb recombinant cccDNA (rcccDNA) bearing a chimeric intron can be produced in the nuclei of these HepG2-HBV/loxP cells. The rcccDNA could be accurately quantified by quantitative PCR using specific primers and cccDNA pool generated in this model could be easily detected by Southern blotting using the digoxigenin probe system. We demonstrated that the rcccDNA was epigenetically organized as the natural minichromosome and served as the template supporting pgRNA transcription and viral replication. As the expression of HBV S antigen (HBsAg) is dependent on the newly generated cccDNA, HBsAg is the surrogate marker of cccDNA. Additionally, the efficacies of 3 classes of anti-HBV agents were evaluated in HepG2-HBV/loxP cells and antiviral activities with different mechanisms were confirmed. These data collectively suggested that HepG2-HBV/loxP cell system will be powerful platform for studying cccDNA related biological mechanisms and developing novel cccDNA targeting drugs. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

  14. Increased resistance to stress corrosion of aluminum alloys

    Science.gov (United States)

    Brummer, S. B.; Cocks, F. H.

    1970-01-01

    Stress corrosion resistance is increased by distorting surface grain-boundary structure and by interrupting the corrosion and stress corrosion. The first is accomplished by machining or shot peening and the second by removal from and later reexposure to the corrosive environment.

  15. 46 CFR 154.412 - Cargo tank corrosion allowance.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Cargo tank corrosion allowance. 154.412 Section 154.412... Containment Systems § 154.412 Cargo tank corrosion allowance. A cargo tank must be designed with a corrosion...) carries a cargo that corrodes the tank material. Note: Corrosion allowance for independent tank type C is...

  16. To the corrosion of austenitic steels in sodium loops

    International Nuclear Information System (INIS)

    Schad, M.

    1978-03-01

    This report describes the comparison between experimental corrosion and calculated corrosion effects on austenitic steels exposed to liquid sodium. As basis for the calculations served a diffusion model. The comparison showed that the model is able to predict the corrosion effects. In addition the model was used to calculate the corrosion effect along an actual fuel rod. (orig.) [de

  17. corrosion of a carbon steel covered by treated bentonites in ...

    African Journals Online (AJOL)

    F. Arbaoui

    2017-09-01

    Sep 1, 2017 ... Keywords: Corrosion inhibitor, Carbon steel, Electrochemical Impedances Spectroscopy;. Algerian bentonites; Tungstate. ... layer of corrosion products formed on the steel surface remains thinner than in aqueous solutions [11]. ..... chloride-induced crevice corrosion of Alloy 22. Corrosion Science, 2013, 68, ...

  18. Corrosion in weldments of electric power plants: Analysis and cure

    International Nuclear Information System (INIS)

    Donati, J.R.; Zacharie, G.

    1990-01-01

    This article reviews some cases of corrosion essentially intergranular and stress corrosion: heat exchanger of LMFBR reactor, stress corrosion by chlorides in the primary coolant circuit, stress corrosion in pure water and sodium hydroxide in steam generators of PWR..., remedies adopted are described in each case [fr

  19. 49 CFR 193.2627 - Atmospheric corrosion control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Atmospheric corrosion control. 193.2627 Section... LIQUEFIED NATURAL GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2627 Atmospheric corrosion... atmospheric corrosion by— (a) Material that has been designed and selected to resist the corrosive atmosphere...

  20. 49 CFR 193.2631 - Internal corrosion control.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Internal corrosion control. 193.2631 Section 193... GAS FACILITIES: FEDERAL SAFETY STANDARDS Maintenance § 193.2631 Internal corrosion control. Each component that is subject to internal corrosive attack must be protected from internal corrosion by— (a...

  1. 49 CFR 192.475 - Internal corrosion control: General.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Internal corrosion control: General. 192.475... Control § 192.475 Internal corrosion control: General. (a) Corrosive gas may not be transported by... taken to minimize internal corrosion. (b) Whenever any pipe is removed from a pipeline for any reason...

  2. 49 CFR 192.461 - External corrosion control: Protective coating.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false External corrosion control: Protective coating... for Corrosion Control § 192.461 External corrosion control: Protective coating. (a) Each external protective coating, whether conductive or insulating, applied for the purpose of external corrosion control...

  3. Formação inicial de professores de Biologia: a metodologia colaborativa mediada pelo computador e a aprendizagem para a docência Pre service education of Biology teachers: the computer-mediated collaborative methodology and learning for teaching

    Directory of Open Access Journals (Sweden)

    Dulcinéia Ester Pagani Gianotto

    2010-01-01

    Full Text Available Este artigo apresenta os resultados da implantação e aplicação da metodologia colaborativa mediada pelo computador desenvolvida com alunos de Prática de Ensino de Biologia da UEM. Apoiando-se na abordagem qualitativa, os dados foram coletados em questionários, documentos e observações, e a análise sobre as ideias, concepções e reflexões dos sujeitos da pesquisa processou-se de acordo com três grupos de elementos formativos para docência construindo a identidade profissional, construção do conhecimento compartilhado e mediação. Concluiu-se que os Alunos-Professores (AP passaram por significativas mudanças atitudinais com relação ao processo de ensino-aprendizagem e ao papel do professor, na medida em que, ao compreenderem a importância de se valorizar o uso da metodologia colaborativa e do computador, como recurso pedagógico no ensino-aprendizagem de Biologia, contemplando-os na experiência vivida, construíram saberes para a docência.This article presents the results of the implantation and application of a computer-mediated collaborative methodology applied to Biology students at Practicum Internship course at the Universidade Estadual de Maringá. Based on qualitative approach, data was collected through questionnaires, documents, in locus observations and analysis of ideas. The conceptions and participants reflections was processed according to three groups of formative elements to teaching constructing a professional identity, construction of shared knowledge and mediation. It follows that student-teachers (ST had significant attitudinal changes regarding the teaching-learning process and concerning the teacher role, as they embrace the importance of appreciate the collaborative methodology and the use of computers as a pedagogical resource in Biology teaching-learning, contemplating this items on their own experience, they were able to constructed knowledge for teaching.

  4. Task E container corrosion studies: Annual report

    International Nuclear Information System (INIS)

    Bunnell, L.R.; Doremus, L.A.; Topping, J.B.; Duncan, D.R.

    1994-06-01

    The Pacific Northwest Laboratory is conducting the Solid Waste Technology Support Program (SWTSP) for Westinghouse Hanford Company (WHC). Task E is the Container Corrosion Study Portion of the SWTSP that will perform testing to provide defensible data on the corrosion of low-carbon steel, as used in drums to contain chemical and radioactive wastes at the Hanford Site. A second objective of Task E is to provide and test practical alternative materials that have higher corrosion resistance than low-carbon steel. The scope of work for fiscal year (FY) 1993 included initial testing of mild steel specimens buried in Hanford soils or exposed to atmospheric corrosion in metal storage sheds. During FY 1993, progress was made in three areas of Task E. First, exposure of test materials began at the Soil Corrosion Test Site where low-carbon steel specimens were placed in the soil in five test shafts at depths of 9 m (30 ft). Second, the corrosion measurement of low-carbon steel in the soil of two solid waste trenches continued. The total exposure time is ∼ 500 days. Third, an atmospheric corrosion test of low-carbon steel was put initiated in a metal shed (Building 2401-W) in the 200 West Area. This annual report describes the Task E efforts and provides a current status

  5. Mesoporous silica nanoparticles for active corrosion protection.

    Science.gov (United States)

    Borisova, Dimitriya; Möhwald, Helmuth; Shchukin, Dmitry G

    2011-03-22

    This work presents the synthesis of monodisperse, mesoporous silica nanoparticles and their application as nanocontainers loaded with corrosion inhibitor (1H-benzotriazole (BTA)) and embedded in hybrid SiOx/ZrOx sol-gel coating for the corrosion protection of aluminum alloy. The developed porous system of mechanically stable silica nanoparticles exhibits high surface area (∼1000 m2·g(-1)), narrow pore size distribution (d∼3 nm), and large pore volume (∼1 mL·g(-1)). As a result, a sufficiently high uptake and storage of the corrosion inhibitor in the mesoporous nanocontainers was achieved. The successful embedding and homogeneous distribution of the BTA-loaded monodisperse silica nanocontainers in the passive anticorrosive SiOx/ZrOx film improve the wet corrosion resistance of the aluminum alloy AA2024 in 0.1 M sodium chloride solution. The enhanced corrosion protection of this newly developed active system in comparison to the passive sol-gel coating was observed during a simulated corrosion process by the scanning vibrating electrode technique (SVET). These results, as well as the controlled pH-dependent release of BTA from the mesoporous silica nanocontainers without additional polyelectrolyte shell, suggest an inhibitor release triggered by the corrosion process leading to a self-healing effect.

  6. Steel corrosion in radioactive waste storage tanks

    International Nuclear Information System (INIS)

    Carranza, Ricardo M.; Giordano, Celia M.; Saenz, E.; Weier, Dennis R.

    2004-01-01

    A collaborative study is being conducted by CNEA and USDOE (Department of Energy of the United States of America) to investigate the effects of tank waste chemistry on radioactive waste storage tank corrosion. Radioactive waste is stored in underground storage tanks that contain a combination of salts, consisting primarily of sodium nitrate, sodium nitrite and sodium hydroxide. The USDOE, Office of River Protection at the Hanford Site, has identified a need to conduct a laboratory study to better understand the effects of radioactive waste chemistry on the corrosion of waste storage tanks at the Hanford Site. The USDOE science need (RL-WT079-S Double-Shell Tanks Corrosion Chemistry) called for a multi year effort to identify waste chemistries and temperatures within the double-shell tank (DST) operating limits for corrosion control and operating temperature range that may not provide the expected corrosion protection and to evaluate future operations for the conditions outside the existing corrosion database. Assessment of corrosion damage using simulated (non-radioactive) waste is being made of the double-shell tank wall carbon steel alloy. Evaluation of the influence of exposure time, and electrolyte composition and/or concentration is being also conducted. (author) [es

  7. Corrosion induced failure analysis of subsea pipelines

    International Nuclear Information System (INIS)

    Yang, Yongsheng; Khan, Faisal; Thodi, Premkumar; Abbassi, Rouzbeh

    2017-01-01

    Pipeline corrosion is one of the main causes of subsea pipeline failure. It is necessary to monitor and analyze pipeline condition to effectively predict likely failure. This paper presents an approach to analyze the observed abnormal events to assess the condition of subsea pipelines. First, it focuses on establishing a systematic corrosion failure model by Bow-Tie (BT) analysis, and subsequently the BT model is mapped into a Bayesian Network (BN) model. The BN model facilitates the modelling of interdependency of identified corrosion causes, as well as the updating of failure probabilities depending on the arrival of new information. Furthermore, an Object-Oriented Bayesian Network (OOBN) has been developed to better structure the network and to provide an efficient updating algorithm. Based on this OOBN model, probability updating and probability adaptation are performed at regular intervals to estimate the failure probabilities due to corrosion and potential consequences. This results in an interval-based condition assessment of subsea pipeline subjected to corrosion. The estimated failure probabilities would help prioritize action to prevent and control failures. Practical application of the developed model is demonstrated using a case study. - Highlights: • A Bow-Tie (BT) based corrosion failure model linking causation with the potential losses. • A novel Object-Oriented Bayesian Network (OOBN) based corrosion failure risk model. • Probability of failure updating and adaptation with respect to time using OOBN model. • Application of the proposed model to develop and test strategies to minimize failure risk.

  8. Corrosion of amalgams under sliding wear.

    Science.gov (United States)

    Lian, K; Meletis, E I

    1996-05-01

    During mastication, dental amalgams are simultaneously subjected to corrosion by the oral environment and to a sliding-wear process by biting forces. In the present study, the effect of sliding wear on the corrosion behavior of two high-copper dental amalgams was investigated. An experimental apparatus was utilized that allows electrochemical testing under sliding-wear conditions. Corrosion potential measurements and anodic polarization scans were conducted in 0.1 M NaCl solution under sliding wear to characterize the behavior of two commercial, high-copper, single composition dental amalgams. In addition, long duration tests were conducted to assess possible corrosion and wear synergistic effects. The results showed that sliding wear caused a sharp reduction in the corrosion potential, a significant increase in the corrosion rate and a decrease in the repassivation rate of both amalgams. These effects are due to the mechanical removal by the wear process of the surface protective film formed on dental amalgams. The simultaneous action of sliding wear and corrosion can also induce embrittlement that leads to cracking. The present evidence suggests that this cracking may be one of the major contributors to marginal failures of dental amalgam restorations.

  9. Marine atmospheric corrosion of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

    Morcillo, M.; Alcantara, J.; Diaz, I.; Chico, B.; Simancas, J.; Fuente, D. de la

    2015-07-01

    Basic research on marine atmospheric corrosion of carbon steels is a relatively young scientific field and there continue to be great gaps in this area of knowledge. The presence of akaganeite in the corrosion products that form on steel when it is exposed to marine atmospheres leads to a notable increase in the corrosion rate. This work addresses the following issues: (a) environmental conditions necessary for akaganeite formation; (b) characterisation of akaganeite in the corrosion products formed; (c) corrosion mechanisms of carbon steel in marine atmospheres; (d) exfoliation of rust layers formed in highly aggressive marine atmospheres; (e) long-term corrosion rate prediction; and (f) behaviour of weathering steels. Field research has been carried out at Cabo Vilano wind farm (Camarinas, Galicia) in a wide range of atmospheric salinities and laboratory work involving the use of conventional atmospheric corrosion techniques and near-surface and bulk sensitive analytical techniques: scanning electron microscopy (SEM)/energy dispersive spectrometry (EDS), X-ray diffraction (XRD), Mossbauer spectroscopy and SEM/μRaman spectroscopy. (Author)

  10. Recent Natural Corrosion Inhibitors for Mild Steel: An Overview

    Directory of Open Access Journals (Sweden)

    Marko Chigondo

    2016-01-01

    Full Text Available Traditionally, reduction of corrosion has been managed by various methods including cathodic protection, process control, reduction of the metal impurity content, and application of surface treatment techniques, as well as incorporation of suitable alloys. However, the use of corrosion inhibitors has proven to be the easiest and cheapest method for corrosion protection and prevention in acidic media. These inhibitors slow down the corrosion rate and thus prevent monetary losses due to metallic corrosion on industrial vessels, equipment, or surfaces. Inorganic and organic inhibitors are toxic and costly and thus recent focus has been turned to develop environmentally benign methods for corrosion retardation. Many researchers have recently focused on corrosion prevention methods using green inhibitors for mild steel in acidic solutions to mimic industrial processes. This paper provides an overview of types of corrosion, corrosion process, and mainly recent work done on the application of natural plant extracts as corrosion inhibitors for mild steel.

  11. Corrosion and alteration of materials from the nuclear industry

    International Nuclear Information System (INIS)

    Beauvy, M.; Berthoud, G.; Defranceschi, M.; Ducros, G.; Feron, D.; Guerin, Y.; Latge, C.; Limoge, Y.; Madic, C.; Santarini, G.; Seiler, J.M.; Vernaz, E.; Richet, C.

    2010-01-01

    The control of the corrosion phenomenon is of prime importance for the nuclear industry. The efficiency and the safety of facilities can be affected by this phenomenon. The nuclear industry has to face corrosion for a large variety of materials submitted to various environments. Metallic corrosion operates in the hot and aqueous environment of water reactors which represent the most common reactor type in the world. Progresses made in the control of the corrosion of the different components of these reactors allow to improve their safety. Corrosion is present in the facilities of the back-end of the fuel cycle as well (corrosion in acid environment in fuel reprocessing plants, corrosion of waste containers in disposal and storage facilities, etc). The future nuclear systems will widen even more the range of materials to be studied and the situations in which they will be placed (corrosion by liquid metals or by helium impurities). Very often, corrosion looks like a patchwork of particular cases in its description. The encountered corrosion problems and their study are presented in this book according to chapters representing the main sectors of the nuclear industry and classified with respect to their phenomenology. This monograph illustrates the researches in progress and presents some results of particular importance obtained recently. Content: 1 - Introduction: context, stakes and goals; definition of corrosion; a complex science; corrosion in the nuclear industry; 2 - corrosion in water reactors - phenomenology, mechanisms, remedies: A - uniform corrosion: mechanisms, uniform corrosion of fuel cladding, in-situ measurement of generalized corrosion rate by electrochemical methods, uniform corrosion of nickel alloys, characterization of the passive layer and growth mechanisms, the PACTOLE code - an integrating tool, influence of water chemistry on corrosion and contamination, radiolysis impact on uniform corrosion; B - stress corrosion: stress corrosion cracking

  12. Aqueous Corrosion Characteristics of Nickel Aluminides

    International Nuclear Information System (INIS)

    Kim, Jung Gu

    1996-01-01

    The aqueous corrosion characteristics of three nickel aluminides were studied by using (a) immersion corrosion test and (b) cyclic anodic polarization measurements. The immersion tests were conducted in 15 different solutions at 25 .deg. C and 95 .deg. C. The nickel aluminides were found to have good corrosion resistance in inorganic acids, organic acids and basic solutions 25 .deg. C except at a higher concentration of hydrochloric acid in ferric chloride solution at the temperature. All three nickel aluminides were suitably resistant to corrosion in the organic acids (oxalic acid, acetic acid), sodium chloride solution, and bases (sodium hydoxide, ammonium hydroxide) at 95 .deg. C. The cyclic anodic polarization curves were developed in N 2 -deaerated solution at 25 .deg. C and 95 .deg. C. In addition, open-circuit corrosion potentials were determined for the solutions in the aerated condition at 25 .deg. C to compare with the anodic curves. At 25 .deg. C, although all materials exhibited active-passive behavior in all solutions except the hydrofluoric acid, at E corr (aerated), passive corrosion was only indicated for the acetic acid, sodium hydroxide, and sodium chloride solutions. Nevertheless, in all cases, the predicted dissolution rates were consistent with immersion test results. Hysteresis loops indicating susceptibility to localized corrosion were observed in 0.6M sodium chloride(pH=7) solution. At 95 .deg. C, active-passive behavior was demonstrated in the acetic acid, sodium chloride, and to a limited extent in the nitric acid: but only active behavior was shown in the sulfuric and hydrofluoric acids. From the above results, it was noted that anodic dissolution of nickel aluminides significantly increased with increasing temperature and that the Cr-containing compositions had better corrosion resistance in several solutions than the Cr-free composition. Prior manufacturing procedures, i.e., casting and powder metallurgy processes did not appear to

  13. Effect of bacterial communities on the formation of cast iron corrosion tubercles in reclaimed water.

    Science.gov (United States)

    Jin, Juntao; Wu, Guangxue; Guan, Yuntao

    2015-03-15

    To understand the role bacterial communities play in corrosion scale development, the morphological and physicochemical characteristics of corrosion scales in raw and disinfected reclaimed water were systematically investigated. Corrosion tubercles were found in raw reclaimed water while thin corrosion layers formed in disinfected reclaimed water. The corrosion tubercles, composed mainly of α-FeOOH, γ-FeOOH, and CaCO3, consisted of an top surface; a shell containing more magnetite than other layers; a core in association with stalks produced by bacteria; and a corroded layer. The thin corrosion layers also had layered structures. These had a smooth top, a dense middle, and a corroded layer. They mostly consisted of the same main components as the tubercles in raw reclaimed water, but with different proportions. The profiles of the dissolved oxygen (DO) concentration, redox potential, and pH in the tubercles were different to those in the corrosion layers, which demonstrated that these parameters changed with a shift in the microbial processes in the tubercles. The bacterial communities in the tubercles were found to be dominated by Proteobacteria (56.7%), Bacteroidetes (10.0%), and Nitrospira (6.9%). The abundance of sequences affiliated to iron-reducing bacteria (IRB, mainly Geothrix) and iron-oxidizing bacteria (mainly Aquabacterium) was relatively high. The layered characteristics of the corrosion layers was due to the blocking of DO transfer by the development of the scales themselves. Bacterial communities could at least promote the layering process and formation of corrosion tubercles. Possible mechanisms might include: (1) bacterial communities mediated the pH and redox potential in the tubercles (which helped to form shell-like and core layers), (2) the metabolism of IRB and magnetic bacteria (Magnetospirillum) might contribute to the presence of Fe3O4 in the shell-like layer, while IRB contributed to green rust in the core layer, and (3) the diversity of

  14. Characterization of Corrosion Products on Carbon Steel Exposed to Natural Weathering and to Accelerated Corrosion Tests

    Directory of Open Access Journals (Sweden)

    Renato Altobelli Antunes

    2014-01-01

    Full Text Available The aim of this work was to compare the corrosion products formed on carbon steel plates submitted to atmospheric corrosion in urban and industrial atmospheres with those formed after accelerated corrosion tests. The corrosion products were characterized by X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy. The specimens were exposed to natural weathering in both atmospheres for nine months. The morphologies of the corrosion products were evaluated using scanning electron microscopy. The main product found was lepidocrocite. Goethite and magnetite were also found on the corroded specimens but in lower concentrations. The results showed that the accelerated test based on the ASTM B117 procedure presented poor correlation with the atmospheric corrosion tests whereas an alternated fog/dry cycle combined with UV radiation exposure provided better correlation.

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

    International Nuclear Information System (INIS)

    BOOMER, K.D.

    2007-01-01

    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

  16. The resistance of titanium to pitting, microbially induced corrosion and corrosion in unsaturated conditions

    International Nuclear Information System (INIS)

    Shoesmith, D.W.; Ikeda, B.M.

    1997-04-01

    Titanium and its alloys (Grades-2, -12, -16) are candidate materials for Canadian nuclear waste containers on the basis of their apparent immunity to many localized corrosion processes. This simplifies markedly the effort needed to justify the use of these materials and to develop models to predict the lifetimes of containers. Here we review the pitting, microbially influenced corrosion (MIC), and corrosion under unsaturated conditions, of titanium. For all these processes, the properties of the passive oxide film are paramount in determining the metal's resistance to corrosion. A review of these oxide properties is included and the conditions to which the metal must be exposed if localized corrosion is to occur are defined. Since these conditions cannot be achieved under Canadian waste vault conditions, it can be concluded that pitting and MIC will not occur and that corrosion under unsaturated conditions is extremely unlikely. (author)

  17. Trend on Corrosion Mitigation Research Paper Publication

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Ki Woung [Korea Institute Of Science and Technology Information, Daejeon (Korea, Republic of)

    2016-10-15

    Those papers were analyzed and arranged in the form of publication years and citation, document types, research areas, source titles, countries and languages, organization and funding agencies. In the 'corrosion mitigation' search, the percentage of the publication number of the nuclear science and technology field was about 12%. The sum of the time cited and the average citation number per item in corrosion mitigation survey were 5059 and 11.47, respectively, while those in nuclear corrosion mitigation survey were 285 and 7.5, respectively. Among 38 source titles, the major ones were Nuclear Eng. and Design, Nuclear Sci. and Eng., Intl. J. of Pressure Vessels and Piping.

  18. Stress corrosion of alloy 600: mechanism proposition

    International Nuclear Information System (INIS)

    Magnin, T.

    1993-01-01

    A fissuring model by stress corrosion based on interactions corrosion-plasticity on the fissure top is proposed to describe the generally intergranular bursting of INCONEL 600 in the PWR. The calculation shows, and some observations check experimentally, that a pseudo intergranular cracking bound to the zigzag micro facets formation along the joints may be so that a completely intergranular bursting. This pseudo intergranular mode makes up a signature of the proposed mechanism. It may be suggested that it may exist one continuity mechanism between the trans and intergranular cracking by stress corrosion of ductile cubic centered faces materials. 2 figs

  19. Corrosion resistant storage container for radioactive material

    Science.gov (United States)

    Schweitzer, D.G.; Davis, M.S.

    1984-08-30

    A corrosion resistant long-term storage container for isolating high-level radioactive waste material in a repository is claimed. The container is formed of a plurality of sealed corrosion resistant canisters of different relative sizes, with the smaller canisters housed within the larger canisters, and with spacer means disposed between juxtaposed pairs of canisters to maintain a predetermined spacing between each of the canisters. The combination of the plural surfaces of the canisters and the associated spacer means is effective to make the container capable of resisting corrosion, and thereby of preventing waste material from leaking from the innermost canister into the ambient atmosphere.

  20. Corrosion Characteristics of the SMART Materials

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Jong Hyuk; Jeong, Y. H.; Choi, B. K.; Soh, J. R.; Lee, D. J.; Choi, B. S

    2000-05-01

    This report summarized the corrosion characteristics of the candidate steam generator tubes (PT-7M, ASTM Gr.2, Inconel-600), which are considering as the core materials in SMART. Also, this evaluated the waterchemstry conditions of commercial power plant including the PWR, BWR, WWER, PHWR, RBMK plants in comparison with that of SMART. And this report described that the microstructures of as-received PT-7M, ASTM Gr.2, and Inconel-600 as the candidate materials of fuel cladding and steam generator tubes and characterized the corrosion properties of the materials, which were tested systematically in the conditions of standard, ammonia solution and ammonia nodular to evaluate the corrosion resistance.

  1. Corrosion products in power generating systems

    International Nuclear Information System (INIS)

    Lister, D.H.

    1980-06-01

    The important mechanisms of corrosion and corrosion product movement and fouling in the heat transport systems of thermal electric generating stations are reviewed. Oil- and coal-fired boilers are considered, along with nuclear power systems - both direct and indirect cycle. Thus, the fireside and waterside in conventional plants, and the primary coolant and steam-raising circuits in water-cooled reactors, are discussed. Corrosion products in organic- and liquid-metal-cooled reactors also are shown to cause problems if not controlled, while their beneficial effects on the cooling water side of condensers are described. (auth)

  2. Corrosion Characteristics of the SMART Materials

    International Nuclear Information System (INIS)

    Baek, Jong Hyuk; Jeong, Y. H.; Choi, B. K.; Soh, J. R.; Lee, D. J.; Choi, B. S.

    2000-05-01

    This report summarized the corrosion characteristics of the candidate steam generator tubes (PT-7M, ASTM Gr.2, Inconel-600), which are considering as the core materials in SMART. Also, this evaluated the waterchemstry conditions of commercial power plant including the PWR, BWR, WWER, PHWR, RBMK plants in comparison with that of SMART. And this report described that the microstructures of as-received PT-7M, ASTM Gr.2, and Inconel-600 as the candidate materials of fuel cladding and steam generator tubes and characterized the corrosion properties of the materials, which were tested systematically in the conditions of standard, ammonia solution and ammonia nodular to evaluate the corrosion resistance

  3. The Leakage determination on corrosion fretting machine

    International Nuclear Information System (INIS)

    Sriyono; Satmoko, Ari; Hafid, Abdul; Febrianto; Prasetio, Joko; Abtokhi; Sumarno, Edy; Handoyo, Ismu; Hidayati, Nur Rahmah; Histori

    1998-01-01

    Fretting machine is an experimental loop to learn fretting corrosion phenomena wich is caused by loading and vibration. On the steam generator, one of the corrosion process that's occurred, it can be caused by vibration between tubes and bending material. Because of high flow rate inside the tube, the high frequency vibration will appeared so it can make the corrosion on bending material more faster. This process can be simulate by fretting machine. This machine has already damage because of leakage. So it will be repaired by dismantling, radiography testing and redrawing. from the result of radiography, the leakage is caused by cracking on bellows seals of the dynamic main support

  4. Corrosion Behavior of Metal Matrix Composites

    Science.gov (United States)

    1993-01-01

    described below. Considering the anodic reaction in chloride media Cu + CI-= CuC1- + e- (1) CuCI - + C1- = CuC1- 2 (2) the corrosion process involves...step. At the lower applied potentials of region 1, the rate of formation of the CuCI is slow in comparison to the transport rate to the interface of...the CP- and the rate of CuCI dissolution, equation (2). In this region, the CuCl is dissolved during the corrosion process and the corrosion behavior

  5. Influence of support design on corrosion

    International Nuclear Information System (INIS)

    Krupowicz, J.J.

    1985-01-01

    The objective of the C-E/EPRI project ''Evaluation of Alternative Materials and Designs in Two Model Steam Generators,'' was to evaluate the corrosion behavior of contemporary or alternative steam generator materials under prototypic design and secondary fault water conditions. This presentation focuses on the influence of support designs on corrosion. When selecting support designs several factors must be taken into account. The alternative materials model tests were useful for comparing the corrosion resistance of materials fabricated into various support configurations including drilled support plates, broached trefoil support plates, egg crate lattice supports and Breda Termomeccanica lattice support systems

  6. A Localised Corrosion Cell for Industrial Applications

    DEFF Research Database (Denmark)

    Andersen, A.; Hilbert, Lisbeth Rischel; Jansen, P.

    2003-01-01

    The LOCORR-CELL™ developed by FORCE TECHNOLOGY is an electrochemical cell for industrial applications estimating localised corrosion. The cell is constructed in a carbon steel casing for direct mounting into the system. It is based on an oxygen concentration element reflecting the interaction...... between the environment formed under a deposit or in a crevice. The essential feature of the method is that it reflects the influence of oxygen content, conductivity and temperature as well as the influence of corrosion inhibitors, MIC and other effects that have an effect on localised corrosion under...

  7. Corrosion and Wear Analysis in Marine Transport Constructions

    OpenAIRE

    Urbahs, A; Savkovs, K; Rijkuris, G; Andrejeva, D

    2018-01-01

    Corrosion is one of the most common naturally occurring processes studied by thermodynamics, which includes oxidation process, metal disruption, and its chemical and electrochemical effects under environmental influence. Corrosion of metal and equipment accounts for a considerable proportion of total corrosion losses, thus providing the impetus for further investigation and developments related to corrosion protection in order to provide transport systems and industry with corrosion preventiv...

  8. Stress corrosion crack growth rates and general corrosion rates at crack tips of steels in high temperature water

    International Nuclear Information System (INIS)

    Speidel, M.O.; Magdowski, R.

    1995-01-01

    The maximum stress corrosion crack growth rates for a number of structural materials (steels and nickel alloys) have been measured in 288 C water. Also, the general corrosion rates of these materials have been determined from weight loss experiments in simulated stress corrosion crack tip electrolytes at 288 C. It is shown that the stress corrosion crack growth rates are typically twenty times faster than the general corrosion rates. This correlation holds over five orders of magnitude. It is concluded that strategies to prevent stress corrosion cracking in high temperature aqueous environments might include alloys of higher general corrosion resistance

  9. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    International Nuclear Information System (INIS)

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-01-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here

  10. The corrosion and corrosion mechanical properties evaluation for the LBB concept in VVERs

    Energy Technology Data Exchange (ETDEWEB)

    Ruscak, M.; Chvatal, P.; Karnik, D.

    1997-04-01

    One of the conditions required for Leak Before Break application is the verification that the influence of corrosion environment on the material of the component can be neglected. Both the general corrosion and/or the initiation and, growth of corrosion-mechanical cracks must not cause the degradation. The primary piping in the VVER nuclear power plant is made from austenitic steels (VVER 440) and low alloy steels protected with the austenitic cladding (VVER 1000). Inspection of the base metal and heterogeneous weldments from the VVER 440 showed that the crack growth rates are below 10 m/s if a low oxygen level is kept in the primary environment. No intergranular cracking was observed in low and high oxygen water after any type of testing, with constant or periodic loading. In the framework of the LBB assessment of the VVER 1000, the corrosion and corrosion mechanical properties were also evaluated. The corrosion and corrosion mechanical testing was oriented predominantly to three types of tests: stress corrosion cracking tests corrosion fatigue tests evaluation of the resistance against corrosion damage. In this paper, the methods used for these tests are described and the materials are compared from the point of view of response on static and periodic mechanical stress on the low alloyed steel 10GN2WA and weld metal exposed in the primary circuit environment. The slow strain rate tests and static loading of both C-rings and CT specimens were performed in order to assess the stress corrosion cracking characteristics. Cyclic loading of CT specimens was done to evaluate the kinetics of the crack growth under periodical loading. Results are shown to illustrate the approaches used. The data obtained were evaluated also from the point of view of comparison of the influence of different structure on the stress corrosion cracking appearance. The results obtained for the base metal and weld metal of the piping are presented here.

  11. Vehicle accelerated corrosion test procedures for automotive in Malaysia

    Directory of Open Access Journals (Sweden)

    Anuar Liza

    2017-01-01

    Full Text Available An accelerated corrosion test, known as proving ground accelerated test, is commonly performed by automotive manufacturers to evaluate the corrosion performance of a vehicle. The test combines corrosion and durability inputs to detect potential failures that may occur during in-service conditions. Currently, the test is conducted at an external test center overseas. Such test is aimed to simulate the effects of one year accelerated corrosion in severe corrosive environment of the north-east and south east of America. However, the test results obtained do not correlate with the actual corrosion conditions observed in the Malaysian market, which is likely attributed to the different test environment of the tropical climate of vehicles in service. Therefore, a vehicle accelerated corrosion test procedure that suits the Malaysian market is proposed and benchmarked with other global car manufacturers that have their own dedicated corrosion test procedure. In the present work, a test track is used as the corrosion test ground and consists of various types of roads for structural durability exposures. Corrosion related facilities like salt trough, mud trough and gravel road are constructed as addition to the existing facilities. The establishment of accelerated corrosion test facilities has contributed to the development of initial accelerated corrosion test procedure for the national car manufacturer. The corrosion exposure is monitored by fitting test coupons at the underbody of test vehicle using mass loss technique so that the desired corrosion rate capable of simulating the real time corrosion effects for its target market.

  12. Development of Copper Corrosion Products and Relation between Surface Appearance and Corrosion Rate

    International Nuclear Information System (INIS)

    Lan, Tran Thi Ngoc; Binh, Nguyen Thi Thanh; Tru, Nguyen Nhi; Yoshino, Tsujino; Yasuki, Maeda

    2008-01-01

    Copper was exposed unsheltered and sheltered in four humid tropical sites, representing urban, urban-industrial, urban-marine and rural environments. The corrosion rates and the sequence of corrosion product formation are presented and discussed in relation with climatic and atmospheric pollution parameters. Chemical compositions of corrosion products were found to depend on environments and duration of exposure. In all environments, cuprite was the predominating corrosion product that formed first and continuously increased during the exposure. Among the sulphur-containing corrosion products, posnjakite and brochantite were more frequently found and the first formed earlier. Nantokite was the most common chlorine-containing products for most cases, except the high-chloride environment, where atacamite was detected instead. The corrosion rate of copper was well indicated by the colour of patina. The red-purple colour corresponded to the high corrosion rate and the greenish grey colour corresponded to the low corrosion rate. Corrosion rate of sheltered copper in urban-marine environment increased with the exposure time

  13. Some observations on phosphate based corrosion inhibitors in preventing carbon steel corrosion

    International Nuclear Information System (INIS)

    Anupkumar, B.; Satpathy, K.K.

    2000-01-01

    Among the various types of phosphonic acid based inhibitors assayed, namely HEDP, ATMP and a commercial corrosion inhibitor (code named Betz), it was found that Betz has the maximum amount of organic phosphate followed by HEDP and ATMP. The corrosion rate studies show that Betz gives the highest inhibition efficiency followed by HEDP and ATMP. This shows that organic phosphate plays a significant role in corrosion protection. However, it was observed that due to synergestic effect, HEDP in the presence of Zn 2+ gave a better corrosion protection than Betz. The results are discussed in the light of available literature. (author)

  14. Biological therapy of psoriasis

    Directory of Open Access Journals (Sweden)

    Sivamani Raja

    2010-01-01

    Full Text Available The treatment of psoriasis has undergone a revolution with the advent of biologic therapies, including infliximab, etanercept, adalimumab, efalizumab, and alefacept. These medications are designed to target specific components of the immune system and are a major technological advancement over traditional immunosuppressive medications. These usually being well tolerated are being found useful in a growing number of immune-mediated diseases, psoriasis being just one example. The newest biologic, ustekinumab, is directed against the p40 subunit of the IL-12 and IL-23 cytokines. It has provided a new avenue of therapy for an array of T-cell-mediated diseases. Biologics are generally safe; however, there has been concern over the risk of lymphoma with use of these agents. All anti-TNF-α agents have been associated with a variety of serious and "routine" opportunistic infections.

  15. Lead Corrosion in Exhibition Ship Models

    National Research Council Canada - National Science Library

    Wegner, Dana

    1997-01-01

    .... However, lead fittings frequently corrode. Corrosion may be so severe as to completely consume the piece, leaving behind a white or gray residue popularly, and aptly, called "lead disease," "lead rot," "lead cancer," or "lead bloom...

  16. Device of capturing for radioactive corrosion products

    International Nuclear Information System (INIS)

    Ohara, Atsushi; Fukushima, Kimichika.

    1984-01-01

    Purpose: To increase the area of contact between the capturing materials for the radioactive corrosion products contained in the coolants and the coolants by producing stirred turbulent flows in the coolant flow channel of LMFBR type reactors. Constitution: Constituent materials for the nuclear fuel elements or the reactor core structures are activated under the neutron irradiation, corroded and transferred into the coolants. While capturing devices made of pure metal nickel are used for the elimination of the corrosion products, since the coolants form laminar flows due to the viscosity thereof near the surface of the capturing materials, the probability that the corrosion products in the coolants flowing through the middle portion of the channel contact the capturing materials is reduced. In this invention, rotating rolls and flow channels in which the balls are rotated are disposed at the upstream of the capturing device to forcively disturb the flow of the liquid sodium, whereby the radioactive corrosion products can effectively be captured. (Kamimura, M.)

  17. A microwave sensor for zinc corrosion detection

    Science.gov (United States)

    Rammal, Jamal; Salameh, Farah; Tantot, Olivier; Delhote, Nicolas; Verdeyme, Serge; Rioual, Stéphane; Gallée, François; Lescop, Benoit

    2017-09-01

    This article presents a sensor based on zinc wires of different widths deposited on the surface of the ceramic resonator capable of detecting and following the evolution of the corrosion of the zinc material. Electromagnetic studies show that due to the evolution of the corrosion, the progressive degradation of the conductivity of the formed zinc grid (from 6 S/μm to 0.015 S/μm) causes a degradation of the quality factor (from Q0 = 50 to Q0 transmission of the TE101 mode of the resonator (from -8 dB to transmission coefficient, and a degradation of the unloaded quality factor. Confirmed by electronic microscopy and X-Ray analysis, these variations are due to the evolution in the corrosion of zinc wires over time, leading to a creation of corrosion products in these wires.

  18. Steamgenerators corrosion monitoring and chemical cleanings

    International Nuclear Information System (INIS)

    Otchenashev, G.

    2001-01-01

    One of the most important secondary side water chemistry objectives is optimization of chemistry conditions to reduce materials corrosion and their products transport into steam generators. Corrosion products (mainly iron and copper oxides) can form deposits on the SG's tubes and essentially decrease their operating resource. The transport of corrosion products by the constant flowrate of feed and blowdown water depends only on their content in these streams. All the internal surfaces (walls, collectors, tubes) were covered with the tough deposit firmly connected with the surface. Corrosion under this deposit was not detected. In some places sludge unconnected with the surface was detected. The lower tubes are located the more unconnected sludge was detected. On SG bottom near the hatch the sludge thickness was about 3 cm. (R.P.)

  19. MODELLING OF NUCLEAR FUEL CLADDING TUBES CORROSION

    Directory of Open Access Journals (Sweden)

    Miroslav Cech

    2016-12-01

    Full Text Available This paper describes materials made of zirconium-based alloys used for nuclear fuel cladding fabrication. It is focused on corrosion problems their theoretical description and modeling in nuclear engineering.

  20. Corrosion resistant alloys for reinforced concrete [2007

    Science.gov (United States)

    2007-07-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for 4-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focused ...

  1. Corrosion resistant alloys for reinforced concrete [2009

    Science.gov (United States)

    2009-04-01

    Deterioration of concrete bridges because of reinforcing steel corrosion has been recognized for four-plus decades as a major technical and economic challenge for the United States. As an option for addressing this problem, renewed interest has focus...

  2. Passive, wireless corrosion sensors for transportation infrastructure.

    Science.gov (United States)

    2011-07-01

    Many industrial segments including utilities, manufacturing, government and infrastructure have an urgent need for a means to detect corrosion before significant damage occurs. Transportation infrastructure, such as bridges and roads, rely on reinfor...

  3. Techniques for the identification of corrosion products

    International Nuclear Information System (INIS)

    Ramanathan, L.V.

    1988-12-01

    This paper presents the different techniques that can be used to identify corrosion/oxidation products through determination of either their composition or their structure, chemical analysis and spectrochemical analysis are commonly used to determine the composition of gross corrosion products. Surface anaLysis techniques such as electron microprobe, AES, ESCA, SIMS, ISS, neutron activation analysis, etc., can be used not only to detect the concentration of the various elements present, but also to obtain the concentration profiles of these elements through the corrosion products. The structure of corrosion products is normally determined with the aid of either X-ray or electron diffraction techniques. This paper describes the basic principles, typical characteristics, limitations and the types of information that can be obtained from each of the techniques along with some typical examples. (author) [pt

  4. Polarized Neutron Reflectometry of Nickel Corrosion Inhibitors.

    Science.gov (United States)

    Wood, Mary H; Welbourn, Rebecca J L; Zarbakhsh, Ali; Gutfreund, Philipp; Clarke, Stuart M

    2015-06-30

    Polarized neutron reflectometry has been used to investigate the detailed adsorption behavior and corrosion inhibition mechanism of two surfactants on a nickel surface under acidic conditions. Both the corrosion of the nickel surface and the structure of the adsorbed surfactant layer could be monitored in situ by the use of different solvent contrasts. Layer thicknesses and roughnesses were evaluated over a range of pH values, showing distinctly the superior corrosion inhibition of one negatively charged surfactant (sodium dodecyl sulfate) compared to a positively charged example (dodecyl trimethylammonium bromide) due to its stronger binding interaction with the surface. It was found that adequate corrosion inhibition occurs at significantly less than full surface coverage.

  5. Towards an understanding of zirconium alloy corrosion

    International Nuclear Information System (INIS)

    Cox, B.

    1976-08-01

    A brief historical summary is given of the development of a programme for understanding the corrosion mechanisms operating for zirconium alloys. A general summary is given of the progress made, so far, in carrying through this programme. (author)

  6. Measurement of reinforcement corrosion in marine structures

    International Nuclear Information System (INIS)

    Mohammad Ismail; Nordin Yahaya

    1999-01-01

    The marine environment is known to be aggressive. Structures constructed on this belt need to undergo periodic assessment in order to ensure no defects or signs of deterioration had occurred. One of the most common deterioration that occurs on marine structures is corrosion of the reinforcement. Corrosion is an electrochemical process. The product of corrosion can increase the reinforcement volume, hence causing cracking on concrete cover. If no action is taken, delamination and spalling of concrete will follow and this will affect the structures integrity. It is therefore important to know the state of the structures condition by monitoring them periodically. NDT techniques that can detect the occurrence of corrosion of reinforcement in concrete uses half cell and resistivity meter. The method of application and interpretation of results are discussed. (author)

  7. A technique for predicting steel corrosion resistance

    Science.gov (United States)

    Novikov, V. F.; Sokolov, R. A.; Neradovskiy, D. F.; Muratov, K. R.

    2018-01-01

    Research works were carried out to develop a technique with the aim to increase the lifetime of steel items used in corrosive media. The possibility to monitor corrosion parameters of steel samples is analyzed on the basis of magnetic properties obtained by means of a magnetic structuroscope DIUS-1.15M designed by the Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences (IMP UB RAS).

  8. Tribo-corrosion of coatings: a review

    Science.gov (United States)

    Wood, Robert J. K.

    2007-09-01

    This paper reviews the available literature relating to the emerging research into the performance of coatings under combined wear and corrosion conditions. Understanding how coatings perform under these tribo-corrosion conditions is essential if the service life of equipment is to be predicted and to allow service life to be extended. Therefore, the tribo-corrosion performance of coatings deposited by a variety of techniques is discussed and the main mechanisms associated with their degradation under combined wear and corrosion highlighted. Coating composition, microstructure, defect level, adhesion, cohesion and substrate properties are seen as some of the critical elements in coating performance when subjected to tribo-corrosion contacts. The importance of post-coating deposition treatments such as laser resurfacing and sealing are also discussed. Interactions between wear and corrosion mechanisms are identified along with some models and mapping techniques that aim to inform coating selection and predict performance. Recent investigations into mono-layer as well as multilayered and functionally graded coatings are reviewed as candidates for wear-corrosion resistant surfaces. The review reveals the need for a more considered approach to tribo-corrosion testing and the way in which the results are analysed and presented. For example, the test conditions should be appropriate to the coating system under test; the level of in situ instrumentation deployed and the post-test analysis of in situ electrochemical data should be carefully selected as well as details given of the composition of any surface tribofilms formed and the identification of the degradation mechanisms.

  9. Emerging Nanotechnology-based Corrosion Control Coatings

    Science.gov (United States)

    2009-02-01

    Al2O3, Fe3O4, Ce (NO3)3, etc. wang Y., et al, Wear, 260, 976-983, 2006. • Epoxy systems with dispersed polyaniline nanoparticles Wessling, B and...triglyceride plus corrosion inhibitor. Koene, B., et al, Proc. Self-healing Conf. 2007 Phenolic varnish plus corrosion inhibitors Stephenson, L, et al US...interactions of nano-sized chemicals Increased surface-to-volume ratio of nanoparticles may result in: -Ingestion through cell membrane -Sensitivity to

  10. Electrochemical and chemical corrosion of chromium

    International Nuclear Information System (INIS)

    Drazic, Dragutin M.; Popic, Jovan P.

    2004-01-01

    It was shown that chromium in deaerated sulfuric acid of pH 1 exhibits two stable corrosion potentials, depending whether the metal had previously been in contact with air or subjected to activation by cathodic evolving hydrogen. Electrochemical polarization measurements, as well as the measurements of the actual metal dissolution rate at the corrosion potential, anodic or cathodic polarization, using the analytical determination of Cr ions in the solution, or volumes of hydrogen evolved, showed that hydrogen can evolve on chromium by three different reaction mechanisms. The first one is the electrochemical hydrogen evolution reaction from H + ions at the bare chromium surface obtained by cathodic activation. This reaction and the active anodic dissolution of chromium determine one stable corrosion potential. The second reaction is the reaction of H + ions on the oxidized chromium surface which, coupled with the anodic dissolution of passivated chromium determines the other stable corrosion potential. The third one is the 'anomalous' or chemical reaction of chromium with water molecules and hydrogen ions whereby hydrogen is liberated. This is a potential independent reaction, occurring on the bare metal surface, and which is at pH 1 several times faster at the corrosion potential than the electrochemical hydrogen evolution reaction. The consequence is that the overall corrosion rate is several times faster than that determined by the usual electrochemical methods. The measurements were performed in the temperature interval 20 - 65 o C and apparent energies of activation for anodic, cathodic and anomalous dissolution reactions were estimated as 63.1, 19.5 and 66.9 kJ mol -1 , respectively. This implies that the anomalous dissolution rate increases more with the increase of temperature than the electrochemical corrosion rate. The applicability of the different methods of measuring electrochemical corrosion rates is discussed. (Author)

  11. Role of hydrogen in stress corrosion cracking

    International Nuclear Information System (INIS)

    Louthan, M.R. Jr.

    1975-01-01

    Hydrogen embrittlement has been postulated as a cause of stress corrosion cracking in numerous alloy systems. Such an interrelationship is useful in design considerations because it permits the designer and working engineer to relate the literature from both fields to a potential environmental compatibility problem. The role of hydrogen in stress corrosion of high strength steels is described along with techniques for minimizing the susceptibility to hydrogen stress cracking. (U.S.)

  12. Data book of anti-corrosion method

    International Nuclear Information System (INIS)

    Lee, Ui Ho

    1997-07-01

    This book deals with cases, influence, cause, standard of corrosion of steel structure, which includes bridges, steel tower, corrosion data, the ocean, ports, and RC structure for civil engineering, exterior materials of construction, building equipment pipes, processing industries such as chemical equipment, oil device, pump and coolant, environment facility like trash incinerator, and sewage process, thermal power generation and nuclear energy generation, and energy industry.

  13. Corrosion Inhibitors as Penetrant Dyes for Radiography

    Science.gov (United States)

    Novak, Howard L.; Hall, Phillip B.

    2003-01-01

    Liquid/vapor-phase corrosion inhibitors (LVCIs) have been found to be additionally useful as penetrant dyes for neutron radiography (and perhaps also x-radiography). Enhancement of radiographic contrasts by use of LVCIs can reveal cracks, corrosion, and other defects that may be undetectable by ultrasonic inspection, that are hidden from direct optical inspection, and/or that are difficult or impossible to detect in radiographs made without dyes.

  14. Aqueous Corrosion Rates for Waste Package Materials

    Energy Technology Data Exchange (ETDEWEB)

    S. Arthur

    2004-10-08

    The purpose of this analysis, as directed by ''Technical Work Plan for: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]), is to compile applicable corrosion data from the literature (journal articles, engineering documents, materials handbooks, or standards, and national laboratory reports), evaluate the quality of these data, and use these to perform statistical analyses and distributions for aqueous corrosion rates of waste package materials. The purpose of this report is not to describe the performance of engineered barriers for the TSPA-LA. Instead, the analysis provides simple statistics on aqueous corrosion rates of steels and alloys. These rates are limited by various aqueous parameters such as temperature (up to 100 C), water type (i.e., fresh versus saline), and pH. Corrosion data of materials at pH extremes (below 4 and above 9) are not included in this analysis, as materials commonly display different corrosion behaviors under these conditions. The exception is highly corrosion-resistant materials (Inconel Alloys) for which rate data from corrosion tests at a pH of approximately 3 were included. The waste package materials investigated are those from the long and short 5-DHLW waste packages, 2-MCO/2-DHLW waste package, and the 21-PWR commercial waste package. This analysis also contains rate data for some of the materials present inside the fuel canisters for the following fuel types: U-Mo (Fermi U-10%Mo), MOX (FFTF), Thorium Carbide and Th/U Carbide (Fort Saint Vrain [FSVR]), Th/U Oxide (Shippingport LWBR), U-metal (N Reactor), Intact U-Oxide (Shippingport PWR, Commercial), aluminum-based, and U-Zr-H (TRIGA). Analysis of corrosion rates for Alloy 22, spent nuclear fuel, defense high level waste (DHLW) glass, and Titanium Grade 7 can be found in other analysis or model reports.

  15. Effects of water chemistry on flow accelerated corrosion and liquid droplet impingement accelerated corrosion

    International Nuclear Information System (INIS)

    Uchida, Shunsuke; Okada, Hidetoshi; Naitoh, Masanori; Koshizuka, Seiichi; Lister, Derek H.; Svoboda, Robert

    2009-01-01

    Overlapping effects of flow dynamics and corrosion are important issues in determining the reliability and lifetime of major structures and components in light water reactor plants. Flow accelerated corrosion (FAC) and liquid droplet impingement (LDI) accelerated corrosion (LDI (corrosion)) are typical phenomena resulting from both interactions. In order to evaluate local wall thinning due to FAC and LDI (corrosion), a 6-step evaluation procedure for each has been proposed. 1. Obtain the flow pattern along the flow path with a 1D computational flow dynamics (CFD) code. 2. Calculate corrosive conditions, e.g., oxygen concentration along the flow path, with a oxygen-hydrazine reaction code for the FAC evaluation. Calculate the flow pattern of liquid droplets in high velocity steam and determine the possibility of their collision with the pipe inner surface for the LDI (corrosion) evaluation. 3. Calculate the mass transfer coefficients at the structure surface with a 3D CFD code for the FAC evaluation. Calculate the frequency of oxide film rupture due to droplet collision for the LDI (corrosion) evaluation. 4. Evaluate high risk zones for FAC and LDI (corrosion) occurrence by coupling major parameters. 5. Calculate wall thinning rates with the coupled model of static electrochemical analysis and dynamic double oxide layer analysis at the identified high FAC and LDI (corrosion) risk zones. 6. Make a final evaluation of residual life and the effectiveness of countermeasures. It was demonstrated that the calculated FAC rates had good agreement with the measured rates. Further investigation of the accuracy of the LDI (corrosion) evaluation procedures is currently in progress. (orig.)

  16. Modelling of zirconium alloys corrosion in LWRs

    International Nuclear Information System (INIS)

    Kritskij, V.G.; Berezina, I.G.; Kritskij, A.V.; Stjagkin, P.S.

    1999-01-01

    Chemical parameters, that exerted effect on Zr+1%Nb alloy corrosion and deserved consideration during reactor operation, were defined and a model was developed to describe the influence of physical and chemical parameters on zirconium alloys corrosion in nuclear power plants. The model is based on the correlation between the zirconium oxide solubility in high-temperature water under the influence of the chemical parameters and the measured values of fuel cladding corrosion under LWR conditions. The intensity of fuel cladding corrosion in the primary circuits depends on the coolant water quality, growth of iron oxide deposits and vaporization portion. Mathematically, the oxidation rate can be expressed as a sum of heat and radiation components. The temperature dependence on the oxidation rate can be described by the Arrenius equation. The radiation component of Zr uniform corrosion equation is a function of several factors such as neutron fluency, the temperature the metallurgical composition and et. We assume that the main factor is the changing of water chemistry and the H 2 O 2 concentration play the determinative role. Probably, the influence of H 2 O 2 is based on the formation of unstable compound ZrO 3 ·nH 2 O and Zr(OH) 4 with high solubility. The validity of the used formulae was confirmed by corrosion measurements on WWER and RBMK fuel cladding. The model can be applied for calculating the reliability of nuclear fuel operation. (author)

  17. Silica nanocontainers for active corrosion protection.

    Science.gov (United States)

    Maia, Frederico; Tedim, João; Lisenkov, Aleksey D; Salak, Andrei N; Zheludkevich, Mikhail L; Ferreira, Mário G S

    2012-02-21

    Novel self-healing protective coatings with nanocontainers of corrosion inhibitors open new opportunities for long-term anticorrosion protection of different metallic materials. In this paper a new type of functional nanoreservoir based on silica nanocapsules (SiNC) synthesized and loaded with corrosion inhibitor 2-mercaptobenzothiazole (MBT) in a one-stage process is reported for the first time. Unlike conventional mesoporous silica nanoparticles, SiNC possess an empty core and shell with gradual mesoporosity, arising from the particular conditions of the synthetic route adopted, which confers significant loading capacity and allows prolonged and stimuli-triggered release of the inhibiting species. The kinetics of inhibitor release was studied at different pH values and concentrations of NaCl. The results show a clear dependence of the release profiles on corrosion relevant triggers such as pH and Cl(-) concentration. When SiNC loaded with MBT are dispersed in NaCl solution, there is a significant decrease of the corrosion activity on aluminium alloy 2024. More importantly, when SiNC-MBT is added to a conventional water-based coating formulation, the modified coating hampers corrosion activity at the metal interface, better than in the case of direct addition of corrosion inhibitor. Furthermore, self-healing is observed before and after artificially inflicting defects in the modified coatings. As a result, the developed nanocontainers show high potential to be used in new generation of active protective coatings. This journal is © The Royal Society of Chemistry 2012

  18. Atmospheric corrosion of uranium-carbon alloys

    International Nuclear Information System (INIS)

    Rousset, P.; Accary, A.

    1965-01-01

    The authors study the corrosion of uranium-carbon alloys having compositions close to that of the mono-carbide; they show that the extent of the observed corrosion effects increases with the water vapour content of the surrounding gas and they conclude that the atmospheric corrosion of these alloys is due essentially to the humidity of the air, the effect of the oxygen being very slight at room temperature. They show that the optimum conditions for preserving U-C alloys are either a vacuum or a perfectly dry argon atmosphere. The authors have also established that the type of corrosion involved is a corrosion which 'cracks under stress' and is transgranular (it can also be intergranular in the case of sub-stoichiometric alloys). They propose, finally, two hypotheses for explaining this mechanism, one of which is illustrated by the existence, at the fissure interface, of corrosion products which can play the role of 'corners' in the mono-carbide grains. (authors) [fr

  19. The multimedia corrosion guide, 2. edition

    International Nuclear Information System (INIS)

    Audisio, S.

    2006-01-01

    Collecting the knowledge and experience of 26 international experts, the Multimedia Corrosion Guide is a reference book in the field of corrosion, for scientists, engineers, technicians and students. Also available in English, the second edition is more than just an update; it contains new chapters, new corrosion case studies and new smart functions. When knowledge is combined with experience, the result is a work of unprecedented quality and detail. Under the supervision of Professor Dr. S. Audisio of the Industrial Physical Chemistry Laboratory, INSA de Lyon, France, leading corrosion specialists from industry (Aerospatiale, CEA, EDF, ELF, Fragema, GDF, Pechiney, Renault, Rhone-Poulenc, Ugine...) have joined forces with experts from renowned French universities (INSA, UTC, ENSEEP, ENSCP, ENSAM...) to produce this book. In addition to the Corrosion Treatise, this program also contains a Case Studies Library, a corrosion database to which users can add their own experience base. New cases are automatically inserted alongside the existing ones, with the same selection criteria. Numerous other advanced functions make this second edition a unique, intelligent, professional and invaluable reference tool. (authors)

  20. Protection of welded joints against corrosion degradation

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2013-01-01

    Full Text Available Welded joints form an integral part of steel constructions. Welded joints are undetachable joints, which are however subjects of corrosion processes. The internal energy increases during the fusion welding especially in the heat affected places around the welded joint, which become initiating spot of corrosion degradation.The aim of the experiment is to put a welded joint produced by the MAG method to a test of corrosion degradation under the conditions of the norm ČSN ISO 9227 (salt-spray test. Organic and inorganic anticorrosion protections were applied on welded beads. First of all, there were prepared welded beads using the method MAG; secondly, metallographical analyses of welded metal, heat affected places and base material were processed. Further, microhardness as well as analysis of chemical composition using the EDS microscope were analysed. Based on a current trend in anticorrosion protections, there were chosen three types of protective coatings. First protective system was a double-layer synthetic system, where the base layer is formed by paint Pragroprimer S2000 and the upper layer by finishing paint Industrol S 2013. Second protective system is a duplex system formed by a combination of a base zinc coating with Zinorex paint. The last protective system was formed by zinc dipping only. Corrosion resistance of the individual tested samples was evaluated based on degradation of protective coating. The corrosion origin as well as the corrosion process were observed, the main criteria was the observation of welded bead.

  1. Corrosion of carbon steel in neutral water

    International Nuclear Information System (INIS)

    Kawai, Noboru; Iwahori, Toru; Kurosawa, Tatsuo

    1983-01-01

    The initial corrosion behavior of materials used in the construction of heat exchanger and piping system of BWR nuclear power plants and thermal power plants have been examined in neutral water at 30, 50, 100, 160, 200, and 285 deg C with two concentrations of dissolved oxygen in the water. In air-saturated water, the corrosion rate of carbon steel was so higher than those in deaerated conditions and the maximum corrosion rate was observed at 200 deg C. The corrosion rate in deaerated water gradually increased with increasing the water temperature. Low alloy steel (2.25 Cr, 1Mo) exhibited good corrosion resistance compared with the corrosion of carbon steel under similar testing conditions. Oxide films grown on carbon steel in deaerated water at 50, 100, 160, 200, and 285 deg C for 48 and 240 hrs were attacked by dissolved oxygen in room temperature water respectively. However the oxide films formed higher than about 160 deg C showed more protective. The electrochemical behavior of carbon steel with oxide films was also similar to the effect of temperature on the stability of oxide films. (author)

  2. Properties of corrosion resistance in C + Mo multi implanted steel

    International Nuclear Information System (INIS)

    Zhang Tonghe; Wu Yuguang; Wang Xiaoyan

    2001-01-01

    The influence of multi-implantation on the corrosion resistance of H13 steel was studied using multi-sweep cyclic voltammetry. The formation conditions of phases and its effects on corrosion resistance were studied. The mechanism of improvement in corrosion resistance was discussed. The experimental results show that the increase of Mo dose can improve corrosion resistance, however the increase of C dose can enhance pitting corrosion potential. Both effects were obtained using dual-and multi-implantation. The passivation layer consists of the phases of Fe 2 Mo, FeMo, MoC, Fe 5 C 3 and Fe 7 C 3 in dual implantation surface of steel. It can improve corrosion resistance and increase pitting corrosion potential. Multi-implantation can further improve corrosion and pitting corrosion resistance compared with dual implantation

  3. Recent Developments on Autonomous Corrosion Protection Through Encapsulation

    Science.gov (United States)

    Li, W.; Buhrow, J. W.; Calle, L. M.; Gillis, M.; Blanton, M.; Hanna, J.; Rawlins, J.

    2015-01-01

    This paper concerns recent progress in the development of a multifunctional smart coating, based on microencapsulation, for the autonomous detection and control of corrosion. Microencapsulation has been validated and optimized to incorporate desired corrosion control functionalities, such as early corrosion detection and inhibition, through corrosion-initiated release of corrosion indicators and inhibitors, as well as self-healing agent release triggered by mechanical damage. While proof-of-concept results have been previously reported, more recent research and development efforts have concentrated on improving coating compatibility and synthesis procedure scalability, with a targeted goal of obtaining easily dispersible pigment-grade type microencapsulated materials. The recent progress has resulted in the development of pH-sensitive microparticles as a corrosion-triggered delivery system for corrosion indicators and inhibitors. The synthesis and early corrosion indication results obtained with coating formulations that incorporate these microparticles are reported. The early corrosion indicating results were obtained with color changing and with fluorescent indicators.

  4. Proceedings of the Ocean Thermal Energy Conversion (OTEC) Biofouling, Corrosion, and Materials Workshop, January 8-10, 1979, Rosslyn, Virginia

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

    The 23 papers presented are entered in the data base separately. Round table sessions on measurement of R/sub f/ and analysis of heat transfer data, biology of fouling, corrosion and the application of materials, and fouling and countermeasures are included. (WHK)

  5. Mechanical and corrosion properties of newly developed biodegradable Zn-based alloys for bone fixation.

    Science.gov (United States)

    Vojtěch, D; Kubásek, J; Serák, J; Novák, P

    2011-09-01

    In the present work Zn-Mg alloys containing up to 3wt.% Mg were studied as potential biodegradable materials for medical use. The structure, mechanical properties and corrosion behavior of these alloys were investigated and compared with those of pure Mg, AZ91HP and casting Zn-Al-Cu alloys. The structures were examined by light and scanning electron microscopy (SEM), and tensile and hardness testing were used to characterize the mechanical properties of the alloys. The corrosion behavior of the materials in simulated body fluid with pH values of 5, 7 and 10 was determined by immersion tests, potentiodynamic measurements and by monitoring the pH value evolution during corrosion. The surfaces of the corroded alloys were investigated by SEM, energy-dispersive spectrometry and X-ray photoelectron spectroscopy. It was found that a maximum strength and elongation of 150MPa and 2%, respectively, were achieved at Mg contents of approximately 1wt.%. These mechanical properties are discussed in relation to the structural features of the alloys. The corrosion rates of the Zn-Mg alloys were determined to be significantly lower than those of Mg and AZ91HP alloys. The former alloys corroded at rates of the order of tens of microns per year, whereas the corrosion rates of the latter were of the order of hundreds of microns per year. Possible zinc doses and toxicity were estimated from the corrosion behavior of the zinc alloys. It was found that these doses are negligible compared with the tolerable biological daily limit of zinc. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  6. Improvements in the corrosion resistance and biocompatibility of biomedical Ti–6Al–7Nb alloy using an electrochemical anodization treatment

    International Nuclear Information System (INIS)

    Huang, Her-Hsiung; Wu, Chia-Ping; Sun, Ying-Sui; Lee, Tzu-Hsin

    2013-01-01

    The biocompatibility of an implant material is determined by its surface characteristics. This study investigated the application of an electrochemical anodization surface treatment to improve both the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for implant applications. The electrochemical anodization treatment produced an Al-free oxide layer with nanoscale porosity on the Ti–6Al–7Nb alloy surface. The surface topography and microstructure of Ti–6Al–7Nb alloy were analyzed. The corrosion resistance was investigated using potentiodynamic polarization curve measurements in simulated blood plasma (SBP). The adhesion and proliferation of human bone marrow mesenchymal stem cells to test specimens were evaluated using various biological analysis techniques. The results showed that the presence of a nanoporous oxide layer on the anodized Ti–6Al–7Nb alloy increased the corrosion resistance (i.e., increased the corrosion potential and decreased both the corrosion rate and the passive current) in SBP compared with the untreated Ti–6Al–7Nb alloy. Changes in the nanotopography also improved the cell adhesion and proliferation on the anodized Ti–6Al–7Nb alloy. We conclude that a fast and simple electrochemical anodization surface treatment improves the corrosion resistance and biocompatibility of Ti–6Al–7Nb alloy for biomedical implant applications. - Highlights: ► Simple/fast electrochemical anodization was applied to biomedical Ti–6Al–7Nb surface. ► Anodized surface had nano-porous topography and contained Al-free oxide layer. ► Anodized surface raised corrosion resistance in three simulated biological solutions. ► Anodized surface enhanced cell adhesion and cell proliferation. ► Electrochemical anodization has potential as biomedical implant surface treatment

  7. Corrosion and Erosion-Corrosion Processes of Metal-Matrix Composites in Slurry Conditions

    Science.gov (United States)

    Flores, J. F.; Neville, A.; Kapur, N.; Gnanavelu, A.

    2012-03-01

    The corrosion and erosion-corrosion (EC) processes of four metal-matrix composites (MMCs) in a simulated cooling water environment have been assessed in this article. The MMCs consisted of two Ni-base and two Fe-base matrices alloyed with different concentrations of chromium, molybdenum, boron, silicon, and carbon; the matrices were reinforced with tungsten carbide (WC) particles. The corrosion behavior has been investigated using a combination of potentiostatic polarization and post-tests surface analysis. The EC processes were studied by in situ electrochemical techniques measuring the current density and corrosion potential response at different slurry temperatures and sand content. At static conditions it was found that as the temperature increased, there was a transition from a homogeneous corrosion of the matrix to an interfacial corrosion mechanism. The Ni-base MMCs showed a better corrosion resistance and interestingly a highly alloyed matrix did not significantly improved MMC's corrosion resistance. In the in situ EC tests, the Fe-base MMCs showed a constant increase in the current density at all sand contents. Whereas, significant changes were not observed in the Ni-base MMCs below 0.5 g/L. Although sand content had an effect on the monitored current density (the current increased as the sand content increased) this effect was less pronounced above 3 g/L.

  8. Exposure testing of fasteners in preservative treated wood : gravimetric corrosion rates and corrosion product analyses

    Science.gov (United States)

    Samuel L. Zelinka; Rebecca J. Sichel; Donald S. Stone

    2010-01-01

    Research was conducted to determine the corrosion rates of metals in preservative treated wood and also understand the mechanism of metal corrosion in treated wood. Steel and hot-dip galvanized steel fasteners were embedded in wood treated with one of six preservative treatments and exposed to 27oC at 100% relative humidity for 1 year. The...

  9. NASA's Beachside Corrosion Test Site and Current Environmentally Friendly Corrosion Control Initiatives

    Science.gov (United States)

    Russell, Richard W.; Calle, Luz Marina; Johnston, Frederick; Montgomery, Eliza L.; Curran, Jerome P.; Kolody, Mark R.

    2013-01-01

    NASA began corrosion studies at the Kennedy Space Center (KSC) in 1966 during the Gemini/Apollo Programs with the evaluation of long-term corrosion protective coatings for carbon steel. KSC's Beachside Corrosion Test Site (BCTS), which has been documented by the American Society of Materials (ASM) as one of the most corrosive, naturally occurring, environments in the world, was established at that time. With the introduction of the Space Shuttle in 1981, the already highly corrosive conditions at the launch pad were rendered even more severe by the acid ic exhaust from the solid rocket boosters. In the years that followed, numerous studies have identified materials, coatings, and maintenance procedures for launch hardware and equipment exposed to the highly corrosive environment at the launch pad. This paper presents a historical overview of over 45 years of corrosion and coating evaluation studies and a description of the BCTS's current capabilities. Additionally, current research and testing programs involving chromium free coatings, environmentally friendly corrosion preventative compounds, and alternates to nitric acid passivation will be discussed.

  10. Initiation and inhibition of pitting corrosion on reinforcing steel under natural corrosion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Abd El Wanees, S., E-mail: s_wanees@yahoo.com [Chemistry Department, Faculty of Science, University of Tabuk, Tabuk (Saudi Arabia); Chemistry Department, Faculty of Science, Zagazig University, Zagazig 44519 (Egypt); Bahgat Radwan, A. [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Alsharif, M.A. [Chemistry Department, Faculty of Science, University of Tabuk, Tabuk (Saudi Arabia); Abd El Haleem, S.M. [Chemistry Department, Faculty of Science, Zagazig University, Zagazig 44519 (Egypt)

    2017-04-01

    Initiation and inhibition of pitting corrosion on reinforcing steel in saturated, naturally aerated Ca(OH){sub 2} solutions, under natural corrosion conditions, are followed through measurements of corrosion current, electrochemical impedance spectroscopy and SEM investigation. Induction period for pit initiation and limiting corrosion current for pit propagation are found to depend on aggressive salt anion and cation-types, as well as, concentration. Ammonium chlorides and sulfates are more corrosive than the corresponding sodium salts. Benzotriazole and two of its derivatives are found to be good inhibitors for pitting corrosion of reinforcing steel. Adsorption of these compounds follows a Langmuir adsorption isotherm. The thermodynamic functions ΔE{sup ∗}, ΔH{sup ∗} and ΔS{sup ∗} for pitting corrosion processes in the absence and presence of inhibitor are calculated and discussed. - Highlights: • Cl{sup −} and SO{sub 4} {sup 2-} induce pitting corrosion on passive reinforcing steel. • Initiation and propagation of pitting depend on cation and anion types. • Inhibition is based on adsorption according to Langmuir isotherm.

  11. Corrosion and corrosion-friction properties of plasma cladding wear-resistant layer on Fe-based alloy

    Science.gov (United States)

    Zhang, Dekun; Yu, Ruoqi; Chen, Kai; Yang, Xuehui; Liu, Yuan; Yin, Yan

    2018-02-01

    Plasma cladding technology is used to prepare a plasma cladding gradient wear-resistant layer, and the corrosion and corrosion-friction properties of the plasma cladding wear-resistant layer are analyzed. The results indicate that under pure immersion corrosion, the plasma gradient cladding wear-resisting layer has better corrosion resistance compared with that of single cladding specimen. No obvious corrosion traces occur on the corrosion surface. Under corrosion-friction conditions, the variety law of friction coefficient can be divided into four stages: rapid decline zone, slight increase zone, fluctuation zone and steady zone. The fluctuation ranges of friction coefficient and wear loss greatly reduce compared with those of dry friction. Furthermore, the wear scar has no obvious corrosion traces. The wear mechanism of the substrate is corrosion wear, adhesive wear, abrasive wear and fatigue wear, while the plasma cladding gradient wear-resistant layer is given priority to with adhesive wear and abrasive wear.

  12. Corrosion Evaluation of Tank 40 Leak Detection Box

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.I.

    1999-07-29

    'Leak detection from the transfer lines in the tank farm has been a concern for many years because of the need to minimize exposure of personnel and contamination of the environment. The leak detection box (LDB) is one line of defense, which must be maintained to meet this objective. The evaluation of a failed LDB was one item from an action plan aimed at minimizing the degradation of LDBs. The Tank 40 LDB, which failed in service, was dug up and shipped to SRTC for evaluation. During a video inspection while in service, this LDB was found to have black tubercles on the interior, which suggested possible microbial involvement. The failure point, however, was believed to have occurred in the drain line from the transfer line jacket. Visual, metallurgical, and biological analyses were performed on the LDB. The analysis results showed that there was not any adverse microbiological growth or significant localized corrosion. The corrosion of the LDB was caused by exposure to aqueous environments and was typical of carbon steel pipes in soil environments.'

  13. Freshwater Corrosion in the Duluth-Superior Harbor: Summary of Initial Workshop Findings, 9 September 2004

    Science.gov (United States)

    2005-03-01

    compounds used to de- chlorinate effluent . The WLSSD plant is located the lower St. Louis River, the area where the highest corrosion rates have been...The possible pres- ence of dissolved tannins related to biological decomposition in connected rivers is also a factor that could affect pH, dissolved...magnesium, sulfate, chloride, iron, copper, zinc, silica, orthophosphate, ammonia, tannins , etc.), conductivity, Ryznar index, Langelier index, and

  14. Corrosion and Protection of Metal in the Seawater Desalination

    Science.gov (United States)

    Hou, Xiangyu; Gao, Lili; Cui, Zhendong; Yin, Jianhua

    2018-01-01

    Seawater desalination develops rapid for it can solve water scarcity efficiently. However, corrosion problem in the seawater desalination system is more serious than that in normal water. So, it is important to pay attention to the corrosion and protection of metal in seawater desalination. The corrosion characteristics and corrosion types of metal in the seawater desalination system are introduced in this paper; In addition, corrosion protect methods and main influencing factors are stated, the latest new technologies about anti-corrosion with quantum energy assisted and magnetic inhibitor are presented.

  15. Survey of Water Chemistry and Corrosion of NPP

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Ki Sok; Hong, Bong Geon

    2008-06-15

    Status of water chemistry of nuclear power plant and materials corrosion has been surveyed. For PWR, system chemistry of primary coolant and secondary coolant as well as the related corrosion of materials was surveyed. For BWR, system chemistry as whole has been surveyed with its accompanying corrosion problems. Radiolysis of coolant water and activation of corrosion products also was surveyed. Future NPP such as supercritical water cooled reactor and fusion reactor has also been surveyed for their water chemistry and corrosion problems. As a result, proposal for some research items has been suggested. Some related corrosion research techniques and electrochemical fundamentals are also presented.

  16. Prediction of corrosion rates of water distribution pipelines according to aggressive corrosive water in Korea.

    Science.gov (United States)

    Chung, W S; Yu, M J; Lee, H D

    2004-01-01

    The drinking water network serving Korea has been used for almost 100 years. Therefore, pipelines have suffered various degrees of deterioration due to aggressive environments. The pipe breaks were caused by in-external corrosion, water hammer, surface loading, etc. In this paper, we focused on describing corrosion status in water distribution pipes in Korea and reviewing some methods to predict corrosion rates. Results indicate that corrosive water of lakes was more aggressive than river water and the winter was more aggressive compared to other seasons. The roughness growth rates of Dongbok lake showed 0.23 mm/year. The high variation of corrosion rates is controlled by the aging pipes and smaller diameter. Also the phenolphthalein test on a cementitious core of cement mortar lined ductile cast iron pipe indicated the pipes over 15 years old had lost 50-100% of their lime active cross sectional area.

  17. High temperature corrosion during biomass firing: improved understanding by depth resolved characterisation of corrosion products

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi; Montgomery, Melanie; Jappe Frandsen, Flemming

    2015-01-01

    The high temperature corrosion of an austenitic stainless steel (TP 347H FG), widely utilised as a superheater tube material in Danish power stations, was investigated to verify the corrosion mechanisms related to biomass firing. KCl coated samples were exposed isothermally to 560 degrees C...... changes within the near surface region (covering both the deposit and the steel surface). Such cross-section analysis was further complemented by plan view investigations (additionally involving X-ray diffraction) combined with removal of the corrosion products. Improved insights into the nature...... of the corrosion products as a function of distance from the deposit surface were revealed through this comprehensive characterisation. Corrosion attack during simulated straw-firing conditions was observed to occur through both active oxidation and sulphidation mechanisms....

  18. Study on influence of native oxide and corrosion products on atmospheric corrosion of pure Al

    International Nuclear Information System (INIS)

    Liu, Yanjie; Wang, Zhenyao; Ke, Wei

    2014-01-01

    Highlights: •Corrosion products layer is only formed in coastal atmosphere. •In coastal atmosphere, rate controlling step is diffusion process. •In rural atmosphere, rate controlling step is charge transfer process. •Pitting area increases greatly in coastal site, but slightly in rural site. -- Abstract: Effects of native oxide and corrosion products on atmospheric corrosion of aluminium in rural and coastal sites were studied by electrochemical impedance spectroscopy (EIS), open-circuit potential (OCP) and scanning electron microscope (SEM) techniques after outdoor exposure. In the rural atmosphere, only the compact, adhesive native oxide layer exists, and the rate controlling step is diffusion process, while in the coastal atmosphere, another loose, inadhesive corrosion products layer exists, and a charge transfer process controls the corrosion process. The pitting area in the coastal atmosphere increases over time more obviously than that in the rural atmosphere

  19. Corrosion rate of steel in concrete - Evaluation of confinement techniques for on-site corrosion rate

    DEFF Research Database (Denmark)

    Nygaard, Peter Vagn; Geiker, Mette Rica; Elsener, Bernhard

    2009-01-01

    to be the main reason for the discrepancies. This paper presents a method for the quantitative assessment of confinement techniques based on monitoring the operation of the corrosion rate instrument and the current distribution between the electrode assembly on the concrete surface and a segmented reinforcement...... bar embedded in the concrete. The applicability of the method was demonstrated on two commercially available corrosion rate instruments based on different confinement techniques. The method provided an explanation of the differences in performance of the two instruments. Correlated measurements...... of linear polarisation resistance and macro-cell currents allowed the determination of calibration factors. Both instruments overestimated the corrosion rate of passive reinforcement, but underestimated the corrosion rate of reinforcement with intense localised corrosion....

  20. Discovery and Characterization of a Novel Lachrymatory Factor Synthase in Petiveria alliacea and Its Influence on Alliinase-Mediated Formation of Biologically Active Organosulfur Compounds1[W][OA

    Science.gov (United States)

    Musah, Rabi A.; He, Quan; Kubec, Roman

    2009-01-01

    A novel lachrymatory factor synthase (LFS) was isolated and purified from the roots of the Amazonian medicinal plant Petiveria alliacea. The enzyme is a heterotetrameric glycoprotein comprised of two α-subunits (68.8 kD each), one γ-subunit (22.5 kD), and one δ-subunit (11.9 kD). The two α-subunits are glycosylated and connected by a disulfide bridge. The LFS has an isoelectric point of 5.2. It catalyzes the formation of a sulfine lachrymator, (Z)-phenylmethanethial S-oxide, only in the presence of P. alliacea alliinase and its natural substrate, S-benzyl-l-cysteine sulfoxide (petiveriin). Depending on its concentration relative to that of P. alliacea alliinase, the LFS sequesters, to varying degrees, the sulfenic acid intermediate formed by alliinase-mediated breakdown of petiveriin. At LFS:alliinase of 5:1, LFS sequesters all of the sulfenic acid formed by alliinase action on petiveriin, and converts it entirely to (Z)-phenylmethanethial S-oxide. However, starting at LFS:alliinase of 5:2, the LFS is unable to sequester all of the sulfenic acid produced by the alliinase, with the result that sulfenic acid that escapes the action of the LFS condenses with loss of water to form S-benzyl phenylmethanethiosulfinate (petivericin). The results show that the LFS and alliinase function in tandem, with the alliinase furnishing the sulfenic acid substrate on which the LFS acts. The results also show that the LFS modulates the formation of biologically active thiosulfinates that are downstream of the alliinase in a manner dependent upon the relative concentrations of the LFS and the alliinase. These observations suggest that manipulation of LFS-to-alliinase ratios in plants displaying this system may provide a means by which to rationally modify organosulfur small molecule profiles to obtain desired flavor and/or odor signatures, or increase the presence of desirable biologically active small molecules. PMID:19692535

  1. Detection of corrosion by radiographic techniques

    International Nuclear Information System (INIS)

    Ahmad, M.; Ashraf, M.M.; Khurshid, U.

    2004-01-01

    Radiation processing technologies are playing an increasing role during manufacturing and subsequent use of everyday products. These technologies are now well established and are extensively practiced in industries, to ensure quality and safety of machinery. Corrosion reduces the operational life of the component, its efficiency and helps generate waste. There is an increasing need to detect and characterize the formation of corrosion in industrial components and assemblies at an early stage. Radiation methods and techniques are applied worldwide to examine defects and corrosion-formation in industrial components. For safety and economic reason, appropriate monitoring of the machinery and industrial components would help reduce accidental risks during operation and avoid production-losses. In the present study, X-ray and neutron-radiography techniques were applied for the inspection and evaluation of corrosion in metallic samples for thickness values of the order of 5 mm or less. Relative contrast at various degrees of metal corrosion product loss was computed theoretical and also measured experimentally by applying radiographic techniques. The relative contrast-sensitivity was also measured in two different ways by X-ray and neutron radiography, to compare the visibility of coarse and fine features. Thick metallic areas, free from sealant and variable paint thickness, were imaged with thermal neutrons beam. Low KV X-rays were also applied for imaging corrosion in metallic components. To optimize exposure-time at low KV in X-ray radiography, a medical film/screen combination was used. X-ray radiography approved to be the more promising technique for imaging of corrosion, as compared to neutron radiography. (author)

  2. RESEARCH OF FRUIT CONSERVES’ CORROSIVE AGGRESSIVENESS

    Directory of Open Access Journals (Sweden)

    I. Kuznecova

    2017-10-01

    Full Text Available Corrosion of metal canning containers is one of the obstacles in spreading its application for packing of food. Particularly aggressive to the metal container is fruit canned medium, containing organic acids.The basic material for the production of metal canning container is white tinplate. The main advantage of white tinplate is the tin compounds are harmless to human organism. For this reason, a white badge is used widely, usually used for production of canning containers, packaging beverages. Despite the fact that recently often used containers made of aluminum badge (foil, the basic material for manufacturing metal canning containers is steel white tinplate.Now applied for coating paints and varnishes do not provide anti-corrosion protection of inner surface of metal containers during storage. Preserving of canned fruit quality in metal containers is largely defined corrosion resistance of the containers. This is due to the fact that the metal transition to canned fruit in due courses of corrosion processes is lowering the nutritional value and deterioration taste of the product, and while allocation of hydrogen is accompanied by swelling and destruction of metal containers.We have investigated a number of anti-corrosion coatings based on Fe-Cr and Fe-Sn-Ti of their behavior in aggressive mediums canned fruit. For the purpose of modeling such mediums the solutions of most widespread organic acids were used. The research allowed conclude, that in surface solid solutions Fe-Sn-Ti increase the corrosion resistance of carbon steel in aqueous solutions of malic, citric and tartaric acids. This implies that the surface solid solutions’ formation can significantly improve corrosion resistance in aggressive canning mediums.

  3. Crevice corrosion of corrosion-resistant alloys in simulated sour gas environments

    International Nuclear Information System (INIS)

    Azuma, S.; Kudo, T.

    1991-01-01

    This paper discusses crevice corrosion behaviors of corrosion-resistant alloys (CRAs) with various Ni, Cr, and Mo contents investigated in conditions simulating the sour gas environment encountered in oil and gas production. Crevice corrosion occurred more easily in a 0.1 MPa H 2 S environment than in a 1.0 MPa H 2 S environment. Ni, Cr and Mo all improved crevice corrosion resistance in electrochemical and immersion tests. The improving effect of Ni and Cr on crevice corrosion resistance reached saturation at 20 percent of their contents. Alloys containing more than 6% Mo exhibited excellent crevice corrosion resistance, which could not be achieved by the increment in Ni and Cr contents. The onset of the crevice corrosion on CRAs in H 2 S-Cl - environment was investigated by electrochemically studying the pH drop in the crevice solution and the depassivation pH (pH d ). These are considered to determine the extent of crevice corrosion resistance in comparison to that in O 2 -Cl - environment. It has been shown that the crevice corrosion frequency from the immersion test in 0.1 MPa H 2 S was better correlated with the pH d in the deaerated solution rather than the pH d in the H 2 S containing solution. The crevice corrosion resistance under 0.1 and 1 MPa H 2 S is discussed in relation to the pH d dependent on the H 2 S concentration in the crevice

  4. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions

    Directory of Open Access Journals (Sweden)

    Carolina Parra

    2017-12-01

    Full Text Available In this work we present a study on the performance of CVD (chemical vapor deposition graphene coatings grown and transferred on Ni as protection barriers under two scenarios that lead to unwanted metal ion release, microbial corrosion and allergy test conditions. These phenomena have a strong impact in different fields considering nickel (or its alloys is one of the most widely used metals in industrial and consumer products. Microbial corrosion costs represent fractions of national gross product in different developed countries, whereas Ni allergy is one of the most prevalent allergic conditions in the western world, affecting around 10% of the population. We found that grown graphene coatings act as a protective membrane in biological environments that decreases microbial corrosion of Ni and reduces release of Ni2+ ions (source of Ni allergic contact hypersensitivity when in contact with sweat. This performance seems not to be connected to the strong orbital hybridization that Ni and graphene interface present, indicating electron transfer might not be playing a main role in the robust response of this nanostructured system. The observed protection from biological environment can be understood in terms of graphene impermeability to transfer Ni2+ ions, which is enhanced for few layers of graphene grown on Ni. We expect our work will provide a new route for application of graphene as a protection coating for metals in biological environments, where current strategies have shown short-term efficiency and have raised health concerns.

  5. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions

    Science.gov (United States)

    Gentil, Dana; del Campo, Valeria; Henrique Rodrigues da Cunha, Thiago; Henríquez, Ricardo; Garín, Carolina; Ramírez, Cristian; Flores, Marcos; Seeger, Michael

    2017-01-01

    In this work we present a study on the performance of CVD (chemical vapor deposition) graphene coatings grown and transferred on Ni as protection barriers under two scenarios that lead to unwanted metal ion release, microbial corrosion and allergy test conditions. These phenomena have a strong impact in different fields considering nickel (or its alloys) is one of the most widely used metals in industrial and consumer products. Microbial corrosion costs represent fractions of national gross product in different developed countries, whereas Ni allergy is one of the most prevalent allergic conditions in the western world, affecting around 10% of the population. We found that grown graphene coatings act as a protective membrane in biological environments that decreases microbial corrosion of Ni and reduces release of Ni2+ ions (source of Ni allergic contact hypersensitivity) when in contact with sweat. This performance seems not to be connected to the strong orbital hybridization that Ni and graphene interface present, indicating electron transfer might not be playing a main role in the robust response of this nanostructured system. The observed protection from biological environment can be understood in terms of graphene impermeability to transfer Ni2+ ions, which is enhanced for few layers of graphene grown on Ni. We expect our work will provide a new route for application of graphene as a protection coating for metals in biological environments, where current strategies have shown short-term efficiency and have raised health concerns. PMID:29292763

  6. Systems Biology

    Indian Academy of Sciences (India)

    IAS Admin

    Systems biology seeks to study biological systems as a whole, contrary to the reductionist approach that has dominated biology. Such a view of biological systems emanating from strong foundations of molecular level understanding of the individual components in terms of their form, function and interactions is promising to ...

  7. Corrosion investigations of high-alloyed steels carried out in different marine area organized by European Federation of Corrosion

    International Nuclear Information System (INIS)

    Birn, J.; Skalski, I.

    1999-01-01

    Research works arranged by EFC Working Party on Marine Corrosion are described. The research was performed in sea areas of Norway, Finland, Sweden, France, Italy, Poland and Netherlands. Subjected to test were three corrosion resistant steel grades; 316, 904 and UNS S 31524. Two corrosion tests were carried out in the years 1993 and 1994 each of min. 6 month duration. The results show that chemical composition of water at salinity level of more than 0.7% has not great effect on corrosion aggressivity in relation to corrosion resistant steels. On the other hand temperature of sea water has great influence on corrosion process. (author)

  8. Mediatized Humanitarianism

    DEFF Research Database (Denmark)

    Vestergaard, Anne

    2014-01-01

    The article investigates the implications of mediatization for the legitimation strategies of humanitarian organizations. Based on a (full population) corpus of ~400 pages of brochure material from 1970 to 2007, the micro-textual processes involved in humanitarian organizations' efforts to legiti......The article investigates the implications of mediatization for the legitimation strategies of humanitarian organizations. Based on a (full population) corpus of ~400 pages of brochure material from 1970 to 2007, the micro-textual processes involved in humanitarian organizations' efforts...... legitimation by accountancy, legitimation by institutionalization, and legitimation by compensation. The analysis relates these changes to a problem of trust associated with mediatization through processes of mediation....

  9. CORROSION ISSUES ASSOCIATED WITH AUSTENITIC STAINLESS STEEL COMPONENTS USED IN NUCLEAR MATERIALS EXTRACTION AND SEPARATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    Mickalonis, J.; Louthan, M.; Sindelar, R.

    2012-12-17

    This paper illustrated the magnitude of the systems, structures and components used at the Savannah River Site for nuclear materials extraction and separation processes. Corrosion issues, including stress corrosion cracking, pitting, crevice corrosion and other corrosion induced degradation processes are discussed and corrosion mitigation strategies such as a chloride exclusion program and corrosion release testing are also discussed.

  10. Surface films and corrosion of copper

    International Nuclear Information System (INIS)

    Hilden, J.; Laitinen, T.; Maekelae, K.; Saario, T.; Bojinov, M.

    1999-03-01

    In Sweden and Finland the spent nuclear fuel is planned to be encapsulated in cast iron canisters that have an outer shield made of copper. The copper shield is responsible for the corrosion protection of the canister construction. General corrosion of the copper is not expected to be the limiting factor in the waste repository environment when estimating the life-time of the canister construction. However, different forms of localised corrosion, i.e. pitting, stress corrosion cracking, or environmentally assisted creep fracture may cause premature failure of the copper shield. Of the probable constituents in the groundwater, nitrites, chlorides, sulphides and carbonates have been suggested to promote localised corrosion of copper. The main assumption made in planning this research program is that the surface films forming on copper in the repository environment largely determine the susceptibility of copper to the different forms of localised corrosion. The availability of reactants, which also may become corrosion rate limiting, is investigated in several other research programs. This research program consists of a set of successive projects targeted at characterising the properties of surface films on copper in repository environment containing different detrimental anions. A further aim was to assess the significance of the anion-induced changes in the stability of the oxide films with regard to localised corrosion of copper. This report summarises the results from a series of investigations on properties of surface films forming on copper in water of pH = 8.9 at temperature of 80 deg C and pressure of 2 MPa. The main results gained so far in this research program are as follows: The surface films forming on copper in the thermodynamic stability region of monovalent copper at 80 deg C consist of a bulk part (about 1 mm thick) which is a good ionic and electronic conductor, and an outer, interfacial layer (0.001 - 0.005 mm thick) which shows p-type semiconductor

  11. Nuclear Repository steel canister: experimental corrosion rates

    Science.gov (United States)

    Caporuscio, F.; Norskog, K.

    2017-12-01

    The U.S. Spent Fuel & Waste Science & Technology campaign evaluates various generic geological repositories for the disposal of spent nuclear fuel. This experimental work analyzed and characterized the canister corrosion and steel interface mineralogy of bentonite-based EBS 304 stainless steel (SS), 316 SS, and low-carbon steel coupons in brine at higher heat loads and pressures. Experiments contrasted EBS with and without an argillite wall rock. Unprocessed bentonite from Colony, Wyoming simulated the clay buffer and Opalinus Clay represented the wall rock. Redox conditions were buffered at the magnetite-iron oxygen fugacity univariant curve. A K-Na-Ca-Cl-based brine was chosen to replicate generic granitic groundwater compositions, while Opalinous Clay groundwater was used in the wall rock series of experiments. Most experiments were run at 150 bar and 300°C for 4 to 6 weeks and one was held at elevated conditions for 6 months. The two major experimental mixtures were 1) brine-bentonite clay- steel, and 2) brine-bentonite clay-Opalinus Clay-steel. Both systems were equilibrated at a high liquid/clay ratio. Mineralogy and aqueous geochemistry of each experiment were evaluated to monitor the reactions that took place. In total 4291 measurements were obtained: 2500 measured steel corrosion depths and 1791 were of phyllosilicate mineral reactions/growths at the interface. The low carbon steel corrosion mechanism was via pit corrosion, while 304 SS and 316 SS were by general corrosion. The low carbon steel corrosion rate (1.95 μm/day) was most rapid. The 304 SS corrosion rate (0.37 μm/day) was slightly accelerated versus the 316 SS corrosion rate (0.26 μm/day). Note that the six month 316 SS experiment shows inhibited corrosion rates (0.07 μm/day). This may be in part due to mantling by the Fe-saponite/chlorite authigenic minerals. All phyllosilicate growth rates at the interface exhibit similar growth rate patterns to the steels (i.e. LCS>304>316> 316 six month).

  12. Corrosion of AISI 304 stainless steel in polluted seawater

    International Nuclear Information System (INIS)

    Brankevich, G.; Guiamet, P.; Videla, H.A.

    1987-01-01

    The sequence of microbiofouling settlement on AISI 304 stain steel samples exposed to polluted harbor sea water of a power cooling water intake is studied. The firts sates of bacterial colonization are followed by means of scanning electron microscopy during two weeks of exposure. The relation between microbiofouling and corrosion is also followed by scanning electron microscopy and evaluated through electrochemical polarization experiments. The results obtained show that microbial colonization and extracellular polimeric substances forming the biofilms have a marked influence on the electrochemical behaviour of stainless steel in sea water. Laboratory experiments using inorganic chloride solutions or artificial sea water show a considerably lesser attack of the metal than those performed 'in situ' with natural sea water. Passivity breadown is highly facilitated when complex biological and inorganic deposits (fouling) have settled on the metal surface. (Author) [pt

  13. Corrosion behaviors and effects of corrosion products of plasma electrolytic oxidation coated AZ31 magnesium alloy under the salt spray corrosion test

    Science.gov (United States)

    Wang, Yan; Huang, Zhiquan; Yan, Qin; Liu, Chen; Liu, Peng; Zhang, Yi; Guo, Changhong; Jiang, Guirong; Shen, Dejiu

    2016-08-01

    The effects of corrosion products on corrosion behaviors of AZ31 magnesium alloy with a plasma electrolytic oxidation (PEO) coating were investigated under the salt spray corrosion test (SSCT). The surface morphology, cross-sectional microstructure, chemical and phase compositions of the PEO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analysis (XRD), respectively. Further, the corrosion process of the samples under the SSCT was examined in a non-aqueous electrolyte (methanol) using electrochemical impedance spectroscopy (EIS) coupled with equivalent circuit. The results show that the inner layer of the coating was destroyed firstly and the corrosion products have significant effects on the corrosion behaviors of the coating. The results above are discussed and an electrochemical corrosion model is proposed in the paper.

  14. Electrophoretic deposition of colloidal particles on Mg with cytocompatibility, antibacterial performance, and corrosion resistance.

    Science.gov (United States)

    Sun, Jiadi; Zhu, Ye; Meng, Long; Chen, Peng; Shi, Tiantian; Liu, Xiaoya; Zheng, Yufeng

    2016-11-01

    Magnesium (Mg) has recently received increasing attention due to its unique biological performance, including cytocompatibility, antibacterial and biodegradable properties. However, rapid corrosion in physiological environment and potential toxicity limits its clinical applications. To improve the corrosion resistance meanwhile not compromise other excellent performance, self-assembled colloidal particles were deposited onto magnesium surfaces in ethanol by a simple and effective electrophoretic deposition (EPD) method. The fabricated functional nanostructured coatings were investigated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analyses, and scanning electron microscopy (SEM). The electrochemical test, pH value, and Mg ion concentration data show that the corrosion resistance of Mg samples is enhanced appreciably after surface treatment. In vitro cellular response and antibacterial capability of the modified Mg substrates are performed. Significantly increased cell adhesion and viability are observed from the coated Mg samples, and the amounts of adherent bacteria on the treated Mg surfaces diminish remarkably compared to the bare Mg. Furthermore, the bare and coated Mg samples were implanted in New Zealand white rabbits for 12 weeks to examine the in vivo long-term corrosion performance and in situ inflammation behavior. The experiment results confirmed that compared with bare Mg substrate the corrosion and foreign-body reactions of the coated Mg samples were suppressed. The above results suggested that our coatings, which effectively enhance the biocompatibility, antimicrobial properties, and corrosion resistance of Mg substrate, provide a simple and practical strategy to expedite clinical acceptance of biodegradableMg and its alloys. Biomedical Mg metals have been considered as promising biodegradable implants because of their intended functions, such as cytocompatibility, antibacterial, and biodegradable properties. However

  15. Guided wave testing for touch point corrosion

    International Nuclear Information System (INIS)

    Alleyne, David

    2012-01-01

    Guided wave testing (GWT) is established in the petrochemical and related industries, primarily for the detection of corrosion flaws. Touch point corrosion at support positions in pipe-work has become a significant problem within many operating gas, chemical and petro-chemical plants world-wide, particularly as a high proportion of these plants have been operational for many decades. This article demonstrates how GWT using guided waves sent axially along the pipe can be performed for the detection and accurate classification of touchpoint corrosion. The major advantage of GWT methods for the detection of touch point corrosion is its ability to examine several support positions from a single easy to access transducer position. The strategy is then to prioritize or rank the condition of the pipe at the supports by removing those with negligible wall loss from scheduling for further inspection. Guided waves are accurate at detecting and classifying corrosion patches at support positions, but deep pits within such patches are more difficult to accurately identify. Examples using data from routine inspection testing are used to support the development of the methods and testing approaches presented. Recent developments of the interpretation methods, testing procedures and calibration methods have significantly enhanced the capabilities of GWT for this important application.

  16. Grain boundary corrosion of copper canister material

    International Nuclear Information System (INIS)

    Fennell, P.A.H.; Graham, A.J.; Smart, N.R.; Sofield, C.J.

    2001-03-01

    The proposed design for a final repository for spent fuel and other long-lived residues in Sweden is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will then be placed in granite bedrock and surrounded by compacted bentonite clay. The canister design is based on a thick cast inner container fitted inside a corrosion-resistant copper canister. During fabrication of the outer copper canisters there will be some unavoidable grain growth in the welded areas. As grains grow they will tend to concentrate impurities within the copper at the new grain boundaries. The work described in this report was undertaken to determine whether there is any possibility of enhanced corrosion at grain boundaries within the copper canister. The potential for grain boundary corrosion was investigated by exposing copper specimens, which had undergone different heat treatments and hence had different grain sizes, to aerated artificial bentonite-equilibrated groundwater with two concentrations of chloride, for increasing periods of time. The degree of grain boundary corrosion was determined by atomic force microscopy (AFM) and optical microscopy. AFM showed no increase in grain boundary 'ditching' for low chloride groundwater. In high chloride groundwater the surface was covered uniformly with a fine-grained oxide. No increases in oxide thickness were observed. No significant grain boundary attack was observed using optical microscopy either. The work suggests that in aerated artificial groundwaters containing chloride ions, grain boundary corrosion of copper is unlikely to adversely affect SKB's copper canisters

  17. Corrosion resistance of tantalum base alloys

    International Nuclear Information System (INIS)

    Gypen, L.A.; Brabers, M.; Deruyttre, A.

    1984-01-01

    The corrosion behaviour of substitutional Ta-Mo, Ta-W, Ta-Nb, Ta-Hf, Ta-Zr, Ta-Re, Ta-Ni, Ta-V, Ta-W-Mo, Ta-W-Nb, Ta-W-Hf and Ta-W-Re alloys has been investigated in various corrosive media, i.e. (1) concentrated sulfuric acid at 250 0 C and 200 0 C, (2) boiling hydrochloric acid of azeotropic composition, (3) concentrated hydrochloric acid at 150 0 C under pressure, (4) HF-Containing solutions and (5) 0.5% H 2 SO 4 at room temperature (anodisation). In highly corrosive media such as concentrated H 2 SO 4 at 250 0 C and concentrated HCl at 150 0 C tantalum is hydrogen embrittled, probably by stress induced precipitation of β-hydride. Both corrosion rate and hydrogen embrittlement in concentrated H 2 SO 4 at 250 0 C are strongly influenced by alloying elements. Small alloying additions of either Mo or Re decrease the corrosion rate and the hydrogen embrittlement, while Hf has the opposite effect. Hydrogen embrittlement in concentrated H 2 SO 4 at 250 0 C is completely eliminated by alloying Ta with 1 to 3 at % Mo (0.5 to 1.5 wt % Mo). These results can be explained in terms of oxygen deficiency of the Ta 2 O 5 film and the electronic structure of these alloys. (orig.) [de

  18. Electrochemistry of stress corrosion cracking of brass

    International Nuclear Information System (INIS)

    Seleet, M.M.

    1986-01-01

    Stress corrosion cracking (SCC) susceptibility of pure copper and two brass (copper-zinc alloy) compositions (80/20 and 60/39) was studied in several ammoniacal and nonammoniacal aqueous solutions at open circuit potential, applying a constant load technique. The SCC tests, using tensile stress and loop specimens, showed pure copper to be immune in all solutions tested, the αΒ'-brass (60/39) alloy to be most susceptible to SCC, and the (80/20) alloy to have intermediate SCC susceptibility. The electrochemical tests (corrosion potential and Tafel plots) were utilized to prove the validity of the dissolution mechanism for the SCC propagation in solution with intermediate corrosion rates (∼0.1 2 ). The electrochemical tests were also used to predict the preferential dissolution of zinc (dezincification) in noncomplexing solutions, and the higher dissolution of copper (than that of zinc) in complexing solutions. The formation of intermediate cuprous complexes was detected using a rotating ring disc electrode (RRDE) composed of a brass (80/20) disc and platinum ring, in ammonium chloride-cupric chloride solution. At very low corrosion rates, the stress corrosion cracking (is present) is assumed to operate by the brittle mechanical fracture mechanism in solution where ammonium ions (NH 4 + ) can be generated

  19. Anomalous dissolution of metals and chemical corrosion

    Directory of Open Access Journals (Sweden)

    DRAGUTIN M. DRAZIC

    2005-03-01

    Full Text Available An overview is given of the anomalous behavior of some metals, in particular Fe and Cr, in acidic aqueous solutions during anodic dissolution. The anomaly is recognizable by the fact that during anodic dissolutionmore material dissolves than would be expected from the Faraday law with the use of the expected valence of the formed ions. Mechanical disintegration, gas bubble blocking, hydrogen embrittlement, passive layer cracking and other possible reasons for such behavior have been discussed. It was shown, as suggested by Kolotyrkin and coworkers, that the reason can be, also, the chemical reaction in which H2O molecules with the metal form metal ions and gaseous H2 in a potential independent process. It occurs simultaneously with the electrochemical corrosion process, but the electrochemical process controls the corrosion potential. On the example of Cr in acid solution itwas shown that the reason for the anomalous behavior is dominantly chemical dissolution, which is considerably faster than the electrochemical corrosion, and that the increasing temperature favors chemical reaction, while the other possible reasons for the anomalous behavior are of negligible effect. This effect is much smaller in the case of Fe, but exists. The possible role of the chemical dissolution reacton and hydrogen evolution during pitting of steels and Al and stress corrosion cracking or corrosion fatigue are discussed.

  20. Corrosion of conducting polymers in aqueous electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Beck, F. (Fachgebiet Elektrochemie, Univ. Duisburg (Germany)); Barsch, U. (Fachgebiet Elektrochemie, Univ. Duisburg (Germany))

    1993-03-22

    The corrosion of polythiophene, poly-bisthiophene and poly-3-methylthiophene in aqueous electrolytes at pH 1 to 13 was investigated. Corrosion rate was determined experimentally by potentiodynamic discharge of residual redox capacity of the conducting polymer after exposure to the corrosion medium. Two corrosion reactions were found to proceed after quasi first order kinetics. The initial rapid process is due to an electrochemical mechanism. The cathodic undoping is balanced by an anodic overoxidation reaction, even at the relatively negative potentials. A rather slow second process is caused by chemical attack of nucleophiles dissolved in the solid at the remaining radical cationic centers. Both rate constants are appreciably larger than those measured previously for polypyrrole, and they increase with increasing pH. The acceleration is due to the more positive redox potentials for the polythiophenes. From the exponential decay of the corrosion potential with time, the same rate constants could be evaluated. In contrast to polypyrrole, the polymer backbone conjugation is not interrupted initially due to -S- [yields] -SO[sub 2]-, and recharge is possible to some extent. (orig.)