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Sample records for organic corrosion inhibitors

  1. Functionalized Nanoparticles and Nanostructures as Carriers for Organic Corrosion Inhibitors

    DTIC Science & Technology

    2009-02-01

    TDA Research Inc.  Wheat Ridge, CO 80033 www.tda.com Clearwater Beach FL February 2-5, 2009 Report Documentation Page Form ApprovedOMB No. 0704-0188...S) AND ADDRESS(ES) TDA Research Inc, Wheat Ridge,CO,80033 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND...DTL-24441 Rust /corrosion removed (in bottom half of panel) to look for undergrowth No corrosion undergrowth, clean scribe Coating scraped to look for

  2. Novel corrosion inhibitor technology

    SciTech Connect

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

    1999-11-01

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

  3. Coking products as corrosion inhibitors

    SciTech Connect

    Antonov, A.V.; Petrenko, V.G.; Frolova, R.P.; Kurinnaya, S.N.

    1982-11-06

    Activated sludge and froth from the biological treatment of coke plant waste waters has been determined to be a corrosion inhibitor in both neutral and acidic media, due to the presence of unreacted coking derived inhibitors, bacteriological formation of inhibitors, bacterial organisms, humic-type organics and traces of germanium, zinc, mercury and manganese. The corrosive liquids tested were, river water, technical system water, gas cooler aqueous condensate, gas collector condensate and coking waste water before and after treatment, the substrate being St 3 steel plates (45 X 45 X 5 M) (time 24-30 hr (acid media) and 934 hr (neutral media)). The activated sludge (25 g/l) reduced acid media corrosion rate by 10/sup 3/, the protective effect being 99% for the test liquids: Sludge is more effective than the froth.

  4. Corrosion inhibitors from expired drugs.

    PubMed

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

    This paper presents a method of expired or unused drugs valorization as corrosion inhibitors for metals in various media. Cyclic voltammograms were drawn on platinum in order to assess the stability of pharmaceutically active substances from drugs at the metal-corrosive environment interface. Tafel slope method was used to determine corrosion rates of steel in the absence and presence of inhibitors. Expired Carbamazepine and Paracetamol tablets were used to obtain corrosion inhibitors. For the former, the corrosion inhibition of carbon steel in 0.1 mol L(-1) sulfuric acid solution was about 90%, whereas for the latter, the corrosion inhibition efficiency of the same material in the 0.25 mol L(-1) acetic acid-0.25 mol L(-1) sodium acetate buffer solution was about 85%.

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

    SciTech Connect

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

    1996-10-01

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

  6. Electrochemical studies of corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    Danford, M. D.

    1990-01-01

    The effect of single salts, as well as multicomponent mixtures, on corrosion inhibition was studied for type 1010 steel; for 5052, 1100, and 2219-T87 aluminum alloys; and for copper. Molybdate-containing inhibitors exhibit an immediate, positive effect for steel corrosion, but an incubation period may be required for aluminum before the effect of a given inhibitor can be determined. The absence of oxygen was found to provide a positive effect (smaller corrosion rate) for steel and copper, but a negative effect for aluminum. This is attributed to the two possible mechanisms by which aluminum can oxidize. Corrosion inhibition is generally similar for oxygen-rich and oxygen-free environments. The results show that the electrochemical method is an effective means of screening inhibitors for the corrosion of single metals, with caution to be exercised in the case of aluminum.

  7. Corrosion Inhibitors for Aluminum.

    ERIC Educational Resources Information Center

    Muller, Bodo

    1995-01-01

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

  8. Corrosion Inhibitors for Aluminum.

    ERIC Educational Resources Information Center

    Muller, Bodo

    1995-01-01

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

  9. sym-Trisubstituted 1,3,5-Triazine Derivatives as Promising Organic Corrosion Inhibitors for Steel in Acidic Solution.

    PubMed

    El-Faham, Ayman; Dahlous, Kholood A; Al Othman, Zeid A; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

    2016-03-31

    Triazine derivatives, namely, 2,4,6-tris(quinolin-8-yloxy)-1,3,5-triazine (T3Q), N²,N⁴,N⁶-tris(pyridin-2-ylmethyl)-1,3,5-triazine-2,4,6-triamine (T3AMPy) and 2,2',2''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)] tris(ethan-1-ol) (T3EA) were synthesized and their inhibition of steel corrosion in hydrochloric acid solution was investigated using electrochemical techniques. The corrosion protection of the prepared compounds increased with increasing concentration and reached up to 98% at 250 ppm. The adsorption of T3Q, T3AMPy, and T3EA on the steel surface was in accordance with the Langmuir adsorption isotherm. The electrochemical results revealed that T3Q, T3AMPy and T3EA act as excellent organic inhibitors and can labeled as mixed type inhibitors. The efficiencies of the tested compounds were affected by the nature of the side chain present in the triazine ring, where T3EA gave the least inhibition while T3Q and T3AMPy gave higher and almost the same inhibition effects. The inhibition efficiencies obtained from the different electrochemical techniques were in good agreement.

  10. Less-toxic corrosion inhibitors

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  12. Migrating corrosion inhibitor protection of concrete

    SciTech Connect

    Bjegovic, D.; Miksic, B.

    1999-11-01

    Migrating corrosion inhibitors (MCI) were developed to protect steel rebar from corrosion in concrete. They were designed to be incorporated as an admixture during concrete batching or used for surface impregnation of existing concrete structures. Two investigations are summarized. One studied the effectiveness of MCIs as a corrosion inhibitor for steel rebar when used as an admixture in fresh concrete mix. The other is a long-term study of MCI concrete impregnation that chronicles corrosion rates of rebar in concrete specimens. Based on data from each study, it was concluded that migrating corrosion inhibitors are compatible with concrete and effectively delay the onset of corrosion.

  13. Quantum chemical assessment of benzimidazole derivatives as corrosion inhibitors

    PubMed Central

    2014-01-01

    Background The majority of well-known inhibitors are organic compounds containing multiple bonds and heteroatoms, such as O, N or S, which allow adsorption onto the metal surface. These compounds can adsorb onto the metal surface and block active surface sites, reducing the rate of corrosion. Results A comparative theoretical study of three benzimidazole isomers, benzimidazole (BI), 2-methylbenzimidazole (2-CH3-BI), and 2-mercaptobenzimidazole (2-SH-BI), as corrosion inhibitors was performed using density functional theory (DFT) with the B3LYP functional basis set. Conclusions Nitro and amino groups were selected for investigation as substituents of the three corrosion inhibitors. Nitration of the corrosion inhibitor molecules led to a decrease in inhibition efficiency, while reduction of the nitro group led to an increase in inhibition efficiency. These aminobenzimidazole isomers represent a significant improvement in the inhibition efficiency of corrosion inhibitor molecules. PMID:24674343

  14. Aluminum corrosion mitigation in alkaline electrolytes containing hybrid inorganic/organic inhibitor system for power sources applications

    NASA Astrophysics Data System (ADS)

    Gelman, Danny; Lasman, Itay; Elfimchev, Sergey; Starosvetsky, David; Ein-Eli, Yair

    2015-07-01

    The severe corrosion accompanied with hydrogen evolution process is the main obstacle preventing the implementation of Al as an anode in alkaline batteries. It impairs the functionality of alkaline battery, due to a drastic capacity loss and a short shelf life. The possibility to reduce Al corrosion rate in alkaline solution with the use of hybrid organic∖inorganic inhibitor based on poly (ethylene glycol) di-acid (PEG di-acid) and zinc oxide (ZnO) was examined in this work. A correlation between an Al corrosion rates and the concentrations of both PEG di-acid and ZnO in alkaline is shown. Selecting 5000 ppm PEG di-acid and 16 gr/l ZnO provides substantial corrosion protection of Al, reducing the corrosion rate in a strong alkaline solution by more than one order of magnitude. Moreover, utilizing the same formulation results in increase in Al-air battery discharge capacity, from 44.5 (for a battery utilizing only KOH in the electrolyte) to 70 mhA/cm2 (for a battery utilizing ZnO/PEG di-acid hybrid inhibitor in the electrolyte). The morphology and composition of the Al electrode surface (studied by SEM, EDS, and XRD) depend on PEG di-acid and ZnO concentrations.

  15. Research on the corrosion inhibitors of zinc in hydrochloric acid

    NASA Astrophysics Data System (ADS)

    Sun, C. X.; Chen, Y. M.; Xu, H. W.; Huang, C. S.; Zhang, M.; Wu, J. Y.; Chen, M.; Xue, M.

    2017-06-01

    Three organic compounds were tested as zinc corrosion inhibitors in hydrochloric acid: cetyltrimethyl ammonium bromide (CTAB), nicotini acid, bromohexadecyl pyridine. The static coupon test results indicate that CTAB and bromohexadecyl pyridine offer the best zinc corrosion protection, while nicotinic acid accelerates zinc corrosion. The polarization results indicate that CTAB, nicotinic acid and bromohexadecyl pyridine induce a positive shift in the E0 of zinc in hydrochloric acid. A complex of CTAB and bromohexadecyl pyridine inhibits the corrosion of zinc in hydrochloric acid. SEM results indicate that the CTAB and bromohexadecyl pyridine formed a uniform and compact membrane on the surface of zinc that subsequently protects the zinc from effective corrosion.

  16. Tall oil fatty acid anhydrides as corrosion inhibitor intermediates

    SciTech Connect

    Fischer, E.R.; Parker, J.E. III

    1995-12-01

    Electrochemical corrosion of carbon steel tubulars in producing oil wells causes lost production and necessitates costly repairs. Corrosive environments exists where hydrocarbons and an aqueous phase are being extracted from producing wells. Tubing life has been extended four fold with the development of organic corrosion inhibitors and concentric configuration treatment. Anhydrides derived from tall oil fatty acids offer enhanced corrosion inhibition properties as compared to traditional dimer/trimer acids. The chemistry of this intermediate and its use in corrosion inhibition for down hole applications, as well as the synthesis of novel oil and water-soluble derivatives will be discussed.

  17. Hydrazino-methoxy-1,3,5-triazine Derivatives' Excellent Corrosion Organic Inhibitors of Steel in Acidic Chloride Solution.

    PubMed

    El-Faham, Ayman; Osman, Sameh M; Al-Lohedan, Hamad A; El-Mahdy, Gamal A

    2016-06-01

    The corrosion inhibition performance of 2-hydrazino-4,6-dimethoxy-1,3,5-tirazine (DMeHT), 2,4-dihydrazino-6-methoxy-1,3,5-triaizine (DHMeT), and 2,4,6-tridydrazino-1,3,5-triaizne (TH₃) on steel corrosion in acidic media was examined using electrochemical techniques. The results showed 2,4-Ddihydrazino-6-methoxy-1,3,5-triaizine (DHMeT) gave the best corrosion protection performance among the other hydrazino derivatives even at a low concentration of 25 ppm (95%). The number of hydrazino groups play an important role in the corrosion inhibition, where the two hydrazine groups increased the electrostatic interactions between the protonated tested compounds, the negatively charged steel surface resulted from the adsorption of the chloride anions, and the presence of the methoxy group made the compound more reliable for formation of film protection on the surface of steel through the lone pair of oxygen atoms. Electrochemical Impedance Spectroscopy (EIS) measurements suggested that the corrosion process of steel in presence of the hydrazino-s-triazine derivatives (TH₃, DMeHT and DHMeT) were being controlled by the charge transfer reaction. Polarization curves indicated that the examined TH₃, DMeHT and DHMeT behaved as mixed type inhibitors.

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    The NASA Kennedy Space Center's 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 indicators, inhibitors and self-healing agents. This allows the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods. Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The release of the inhibitors from the microparticles in basic solution was studied. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed. The inhibition efficacy of the inhibitors, incorporated directly and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

  19. Protection of Aluminum against Corrosion by Incorporation of Organic Inhibitors into Paints and Primers

    DTIC Science & Technology

    1984-07-01

    standard Forest Products Laboratory (FPL) etch treatment. Wedge test adhesion analysis allowed evaluation of the compatibility of inhibitor-treated...nitrilotris methylene phosphonic acid (NTMP) has been shown to 14V move the durability of treated Forest Products Laboratories (FPL) and | J phosphoric acid...immersed in 80°C water for several minutes, a hydration product grows on the surface to fill the pores and "mud cracks" of the * original oxide. This is

  20. A novel molluscicide, corrosion inhibitor, and dispersant

    SciTech Connect

    Kreuser, R.T.; Vanlaer, A.; Damour, A.

    1997-12-01

    The efficacy of filming amines as corrosion inhibitors and dispersants in steam systems is well-documented. A novel formulation retains these functions of traditional filming amines and adds molluscicide capability for controlling macrofouling in fresh water and sea water. Criteria for this development included low toxicity to mammals and to non-target aquatic species, rapid biodegradation, and multifunctionality. Low mammalian toxicity and lack of other hazards exempt it from reporting requirements under SARA Title 3. Toxicity (LC{sub 50}) levels for rainbow trout and fathead minnow are higher than typical dosage rates. Biodegradation is rapid; half life is 22 hours in river water. By effectively dispersing slimes (along with biofilm, scale, and tubercles), it controls slimes without toxicity to biofilm organisms. As corrosion inhibitor, it reduces the open cell potential of metal surfaces by 50--200 millivolts and retards pitting and crevice corrosion. Its molluscicide activity gradually kills and disperses mussels, clams, and barnacles. The protective film, renewed by dosage for a brief period of time each day, proactively prevents scale and slime deposits and repels settling and adhesion by macrofouling species. Refinement of established technology has produced a multi-functional formulation that is safe to handle and has minimal impact on the environment.

  1. Alkylaniline/formaldehyde oligomers as corrosion inhibitors

    SciTech Connect

    Bacskai, R.; Schroeder, A.H.

    1988-10-25

    This patent describes a method of inhibiting corrosion of a corrodible metal material in or around a well through which a corrosive fluid is produced, which comprises contacting the metal material with an effective amount of a corrosion inhibitor composition comprising the reaction product obtained by the acid-catalyzed oligomerization of: (A) an alkylaniline having from 4 to 30 carbon atoms in the alkyl substituent, and (B) formaldehyde.

  2. Corrosion protection with eco-friendly inhibitors

    NASA Astrophysics Data System (ADS)

    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.

  3. Electrochemical screening of organic and inorganic inhibitors for the corrosion of ASTM A-470 steel in concentrated sodium hydroxide solution

    SciTech Connect

    Moccari, A.; MacDonald, D.D.

    1985-05-01

    The corrosion of ASTM A-470 turbine disk steel in concentrated sodium hydroxide solution (10 mol/kg) containing sodium silicate, sodium dihydrogen phosphate, sodium chromate, aniline and some of its derivatives, tannic acid, L-(-)-phenylalanine (aminopropionic acid) and octadecylamine as potential inhibitors has been studied using the potentiodynamic, AC impedance, and Tafel extrapolation techniques. All tests were performed at 115 + or - 2 C. The anodic and cathodic polarization data show that aniline and its derivatives, L-(-)-phenylalanine, NaH/sub 2/PO/sub 4/, Na/sub 2/SiO/sub 3/, and Na/sub 2/CrO/sub 4/ inhibit the anodic process, whereas tannic acid inhibits the cathodic reaction. Octadecylamine was found to inhibit both the anodic and cathodic processes. The mechanisms of inhibition for some of these compounds have been inferred from the wide band width frequency dispersions of the interfacial impedance.

  4. Effect of Wall Shear Stress on Corrosion Inhibitor Film Performance

    NASA Astrophysics Data System (ADS)

    Canto Maya, Christian M.

    In oil and gas production, internal corrosion of pipelines causes the highest incidence of recurring failures. Ensuring the integrity of ageing pipeline infrastructure is an increasingly important requirement. One of the most widely applied methods to reduce internal corrosion rates is the continuous injection of chemicals in very small quantities, called corrosion inhibitors. These chemical substances form thin films at the pipeline internal surface that reduce the magnitude of the cathodic and/or anodic reactions. However, the efficacy of such corrosion inhibitor films can be reduced by different factors such as multiphase flow, due to enhanced shear stress and mass transfer effects, loss of inhibitor due to adsorption on other interfaces such as solid particles, bubbles and droplets entrained by the bulk phase, and due to chemical interaction with other incompatible substances present in the stream. The first part of the present project investigated the electrochemical behavior of two organic corrosion inhibitors (a TOFA/DETA imidazolinium, and an alkylbenzyl dimethyl ammonium chloride), with and without an inorganic salt (sodium thiosulfate), and the resulting enhancement. The second part of the work explored the performance of corrosion inhibitor under multiphase (gas/liquid, solid/liquid) flow. The effect of gas/liquid multiphase flow was investigated using small and large scale apparatus. The small scale tests were conducted using a glass cell and a submersed jet impingement attachment with three different hydrodynamic patterns (water jet, CO 2 bubbles impact, and water vapor cavitation). The large scale experiments were conducted applying different flow loops (hilly terrain and standing slug systems). Measurements of weight loss, linear polarization resistance (LPR), and adsorption mass (using an electrochemical quartz crystal microbalance, EQCM) were used to quantify the effect of wall shear stress on the performance and integrity of corrosion inhibitor

  5. Agricultural Polymers as Corrosion Inhibitors

    USDA-ARS?s Scientific Manuscript database

    Agricultural polymers were composed of extra-cellular polysaccharides secreted by Leuconostoc mesenteroides have been shown to inhibit corrosion on corrosion-sensitive metals. The substantially pure exopolysaccharide has a general structure consisting of alpha(1-6)-linked D-glucose backbone and appr...

  6. Corrosion inhibiting organic coatings

    SciTech Connect

    Sasson, E.

    1984-10-16

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

  7. Diffusion Coatings as Corrosion Inhibitors

    NASA Astrophysics Data System (ADS)

    Ivanov, Radoslav; Ignatova-Ivanova, Tsveteslava

    2016-03-01

    Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of B2O3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH4)2.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of B2O3), and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

  8. Super-Hydrophobic Green Corrosion Inhibitor On Carbon Steel

    NASA Astrophysics Data System (ADS)

    Hassan, H.; Ismail, A.; Ahmad, S.; Soon, C. F.

    2017-06-01

    There are many examples of organic coatings used for corrosion protection. In particular, hydrophobic and super-hydrophobic coatings are shown to give good protection because of their enhanced ability to slow down transport of water and ions through the coating. The purpose of this research is to develop water repellent coating to avoid direct contact between metal and environment corrosive and mitigate corrosion attack at pipeline system. This water repellent characteristic on super-hydrophobic coating was coated by electrodeposition method. Wettability of carbon steel with super-hydrophobic coating (cerium chloride and myristic acid) and oxidized surface was investigated through contact angle and inhibitor performance test. The inhibitor performance was studied in 25% tannin acid corrosion test at 30°C and 3.5% sodium chloride (NaCl). The water contact angle test was determined by placing a 4-μL water droplet of distilled water. It shows that the wettability of contact angle super-hydrophobic with an angle of 151.60° at zero minute can be classified as super-hydrophobic characteristic. By added tannin acid as inhibitor the corrosion protection on carbon steel becomes more consistent. This reveals that the ability of the coating to withstand with the corrosion attack in the seawater at different period of immersions. The results elucidate that the weight loss increased as the time of exposure increased. However, the corrosion rates for uncoated carbon steel is high compared to coated carbon steel. As a conclusion, from both samples it can be seen that the coated carbon steel has less corrosion rated compared to uncoated carbon steel and addition of inhibitor to the seawater provides more protection to resist corrosion attack on carbon steel.

  9. Corrosion Inhibitors as Penetrant Dyes for Radiography

    NASA Technical Reports Server (NTRS)

    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.

  10. Effervescent Cationic Film Forming Corrosion Inhibitor Material and Process.

    DTIC Science & Technology

    1990-09-24

    corrosion 13 inhibitor material into the water to form a solution that coats 14 the exposed aluminum surfaces of the weapon with a cation film of 15 the corrosion inhibitor material. 14 OD~ ODV DATE:W

  11. Evaluation of Encapsulated Inhibitor for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  12. Waste of cleaning emulsion sewage as inhibitors of steel corrosion

    NASA Astrophysics Data System (ADS)

    Fazullin, D. D.; Mavrin, G. V.; Shaikhiev, I. G.

    2016-06-01

    The article describes the corrosion test of steel of the brand 20 in the stratal water. To increase corrosion resistance as a corrosion inhibitor the concentrate waste emulsion of the mark "Incam- 1" was provided. The article presents studies of the corrosion rate with different dosages of corrosion inhibitor in the stratal water. Based on these research results are revealed that the degree of protection of steel is 27% at a dosage of 3.8 g / dm3.

  13. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Inhibitors which appeared promising in previous tests and additional inhibitors including several proprietary products were evaluated. Evaluation of the inhibitors was based on corrosion protection afforded an aluminum-mild steel-copper-stainless steel assembly in a hot corrosive water. Of the inhibitors tested two were found to be effective and show promise for protecting multimetallic solar heating systems.

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

    NASA Technical Reports Server (NTRS)

    Pearman, Benjamin Pieter; Calle, Luz M.

    2015-01-01

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

  15. Release Properties and Electrochemical Characterization of Encapsulated Corrosion Inhibitors for Environmentally Friendly Smart Coatings

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

    The NASA Kennedy Space Center's 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 indicators, inhibitors and self-healing agents. This allows for the incorporation of autonomous corrosion control functionalities, such as corrosion detection and inhibition as well as the self-healing of mechanical damage, into coatings. This paper presents technical details on the characterization of inhibitor-containing particles and their corrosion inhibitive effects using electrochemical and mass loss methods. Three organic environmentally friendly corrosion inhibitors were encapsulated in organic microparticles that are compatible with desired coatings. The total inhibitor content and the release of one of the inhibitors from the microparticles in basic solution was measured. Particles with inhibitor contents of up 60 wt% were synthesized. Fast release, for immediate corrosion protection, as well as long-term release for continued protection, was observed. The inhibition efficacy of the inhibitors, both as the pure materials and in microparticles, on carbon steel was evaluated. Polarization curves and mass loss measurements showed that, in the case of 2MBT, its corrosion inhibition effectiveness was greater when it was delivered from microparticles.

  16. Hydroxyethyl cellulose as efficient organic inhibitor of zinc-carbon battery corrosion in ammonium chloride solution: Electrochemical and surface morphology studies

    NASA Astrophysics Data System (ADS)

    Deyab, M. A.

    2015-04-01

    Hydroxyethyl cellulose (HEC) has been investigated as corrosion inhibitor for zinc-carbon battery by polarization and electrochemical impedance spectroscopy (EIS) measurements. The obtained results show that the maximum inhibition efficiency by HEC in 26% NH4Cl solution at 300 ppm and 298 K is 92.07%. Tafel polarization studies reveal that HEC acts as an efficient mixed inhibitor. The corrosion rate is suppressed by the adsorption of HEC on the zinc surface. HEC adsorption obeys the Langmuir isotherm and the thermodynamic parameters Kads and Δ Gadso have been also calculated and discussed. Both physisorption and chemisorption may occur on the zinc surface. Surface characterization investigation using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) is used to ascertain the nature of the protective film.

  17. Materials Evaluation. Part II. Development of Corrosion Inhibitors.

    DTIC Science & Technology

    1979-09-01

    and Identify by block number) A borax -nitrite based inhibitor has been developed for incorporation into the Air Force Rinse Facility at MacDill Air...Block 20 inhibitors has been tested and a borax -nitrite based formulation developed which inhibits the corrosion of several ferrous and nonferrous...alternatives to chromates, one such alternative being a borax -nitrite based inhibitor. The value of borax nitrite as a corrosion inhibitor has long been

  18. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, B.A.; Whitlow, E.P.

    1998-09-22

    A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

  19. Corrosion inhibitor for aqueous ammonia absorption system

    DOEpatents

    Phillips, Benjamin A.; Whitlow, Eugene P.

    1998-09-22

    A method of inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425.degree. F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25.degree. C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425.degree. F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer.

  20. Dual Use Corrosion Inhibitor and Penetrant for Anomaly Detection in Neutron/X Radiography

    NASA Technical Reports Server (NTRS)

    Hall, Phillip B. (Inventor); Novak, Howard L. (Inventor)

    2004-01-01

    A dual purpose corrosion inhibitor and penetrant composition sensitive to radiography interrogation is provided. The corrosion inhibitor mitigates or eliminates corrosion on the surface of a substrate upon which the corrosion inhibitor is applied. In addition, the corrosion inhibitor provides for the attenuation of a signal used during radiography interrogation thereby providing for detection of anomalies on the surface of the substrate.

  1. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

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

  2. Green corrosion inhibitors: An oil company perspective

    SciTech Connect

    McMahon, A.J.; Harrop, D.

    1995-10-01

    Environmental concerns are increasingly likely to influence the choice of oilfield production and drilling chemicals. The Paris Commission (PARCOM) is currently developing legislation for the North Sea. The regulations which emerge may well restrict the use of many current products. Uncertainty over the eventual details has meant that new product development has been somewhat tentative. Little genuinely new chemistry has been explored to meet the environmental challenge. Polypeptides are one of several new classes which deserve attention. Polyaspartate is the most efficient corrosion inhibitor (ca 80% max) of the polypeptides. Molecular weight (1,000--22,000) does not affect the efficiency but both high [Ca{sup 2+}] and high pH are beneficial. Performance is particularly good in batch treatment tests (> 95% efficiency).

  3. Corrosion inhibitors for water-base slurry in multiblade sawing

    NASA Technical Reports Server (NTRS)

    Chen, C. P.; Odonnell, T. P.

    1982-01-01

    The use of a water-base slurry instead of the standard PC oil vehicle was proposed for multiblade sawing (MBS) silicon wafering technology. Potential cost savings were considerable; however, significant failures of high-carbon steel blades were observed in limited tests using a water-based slurry during silicon wafering. Failures were attributed to stress corrosion. A specially designed fatigue test of 1095 steel blades in distilled water with various corrosion inhibitor solutions was used to determine the feasibility of using corrosion inhibitors in water-base MBS wafering. Fatigue tests indicate that several corrosion inhibitors have significant potential for use in a water-base MBS operation. Blade samples tested in these specific corrosion-inhibitor solutions exhibited considerably greater lifetime than those blades tested in PC oil.

  4. Evaluation of corrosion inhibitor for low-pH ammonium nitrate-methanol completion fluid

    SciTech Connect

    Krilov, Z.; Soric, T.; Tomic, M.; Wojtanowicz, A.K.

    1997-02-01

    A specially formulated completion fluid, low-pH ammonium nitrate-methanol-water mixture (ANM), compatible with argillaceous and calcareous Adriatic Sea sandstone formations, appears to be very corrosive for steel wellbore equipment. More than 12 commercially available, as well as some originally formulated, chemical additives were laboratory tested at room temperature using weight-loss and electrochemical methods to find an effective corrosion inhibitor for ANM. Two inhibitors, a commercially available, organic, amine base (OA) and an originally formulated, inorganic, ammonium dihydrogen phosphate base (IB), showed effective protection of carbon steel in contact with ANM fluid (corrosion rate was less than 5 mil/yr). Both selected corrosion inhibitors did not exhibit any additional rock permeability impairment during fluid-rock compatibility flow tests if ANM fluid was filtered before injection into the core samples. For inorganic inhibitor IB, additional filtration of inhibited fluid is not required.

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

    PubMed

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

    2010-11-01

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

  6. Polypeptide Inhibitors of Mineral Scaling and Corrosion

    DTIC Science & Technology

    1990-06-30

    and the method of synthesis are subjects of patent applications. Corrosion inhibition has been demonstrated using polyaspartate , the simplest...observed that polyaspartate caused an upward shift in the open circuit potential (Ecorr), suggesting some anodic control of corrosion. However, Tafel...the presence of polypeptides are In progress. Examination of thermal polyaspartate effects on polarization resistance corrosion of 304 stainless

  7. Low toxic corrosion inhibitors for aluminum in fresh water

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Combinations of chemical compounds that reportedly reduce the corrosion of aluminum in fresh water were evaluated. These included combinations of borates, nitrates, nitrites, phosphates, silicates, and mercaptobenzothiazole. Eight of fifty inhibitor combinations evaluated gave excellent corrosion protection and compared favorably with sodium chromate, which has generally been considered standard for many years.

  8. An update of corrosion inhibitors for mild steel exposed to 32-0-0 UAN solution

    SciTech Connect

    Nguyen, D.T.; Nichols, D.E.; Lohry, E.J.

    1994-10-01

    This is a continuation of corrosion studies on the effectiveness of commercial and newly-developed corrosion inhibitors for use with mild steel exposed to urea-ammonium nitrate (UAN) solution. This paper provides updated information on five newly-developed corrosion inhibitors. Tests were conducted with mild steel exposed to 32-0-0 UAN solution containing each corrosion inhibitor at ambient temperature and under static conditions. Real-time corrosion of the test specimens was monitored using AC impedance techniques. Corrosion performance of the inhibitors was evaluated based on comparison of the corrosion rate of specimens exposed to 32-0-0 UAN solution with and without a corrosion inhibitor.

  9. The Influence of Water-Displacing Organic Corrosion Inhibitors on the Fatigue Behaviour of 2024-T3 Alclad Aluminium Alloy Bolted Joints.

    DTIC Science & Technology

    1982-01-01

    INTRODUCTION I 2. MATERIAL AND SPECIMENS 1 2.1 Test Material 1 2.2 Types of Specimens 2 3. FATIGUE TESTING 3 4. TEST RESULTS 4 4.1 Fatigue Tests 4 4.2 Fracture...8217 and ’high’ load transfer construction and high and low bolt clamping forces, comple- mentary tests being made in all cases with the joint components...assembled either ’dry’ or after coating with an organic corrosion-inhibiting preparation. 2. MATERIAL AND SPECIMENS 2.1 Test Material Three sheets of

  10. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

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

  11. The Corrosion and Preservation of Iron Antiques.

    ERIC Educational Resources Information Center

    Walker, Robert

    1982-01-01

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

  12. Sulphonamides as corrosion inhibitor: Experimental and DFT studies

    NASA Astrophysics Data System (ADS)

    Obayes, Hasan R.; Al-Amiery, Ahmed A.; Alwan, Ghadah H.; Abdullah, Thamer Adnan; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar

    2017-06-01

    Inhibitors are synthetic and natural molecules have various functional groups like double or triple bonds and heteroatoms; N, O or S, which permit adsorption onto the MS (metal surface). These inhibitors have the ability to adsorb onto the MS and block the active site that was reducing the corrosion rate. Inhibition efficiencies of the investigated compounds: Sulfacetamide (SAM), Sulfamerazine (SMR), Sulfapyridine (SPY) and Sulfathiazole (STI), as inhibitors in corrosive solution were evaluated based on weight loss technique. Nitro and Amino groups were chosen for the study of the substituted reaction of four corrosion inhibitor compounds: SAM, SMR, SPY and STI, theoretically utilizing the thickness capacities hypothesis DFT (density functions theory) method with the level [rB3LYP/6-311G(d,p)]. Our research demonstrated that the nitration of studied molecules lead to a diminishing in inhibition efficiencies, group lead to an increase in inhibition efficiency. Compared with corrosion inhibitor molecules these results gave a significant improvement in inhibition efficiency for corrosion inhibitor molecules.

  13. Corrosion inhibitor evaluation for a gas compression system

    SciTech Connect

    Perdomo, J.J.; Ramirez, M.; Viloria, A.; Morales, J.L.

    1999-11-01

    The injection of chemicals for gas systems is a common practice to prevent corrosion and asphaltene deposition. A laboratory study was conducted to evaluate 5 commercially available corrosion inhibitors and an asphaltene dispersant for a gas compression plant. This study was set out to look at the compatibility of a pipeline corrosion inhibitor with both an anti asphaltene and a gas compression inhibitor which is required to have a relatively large flammable point and resist the pressure and temperature of the process without igniting or aging. Also, the effect of precorroded surfaces was studied to establish its effect on the performance of the pipeline inhibitor. The efficiency of the products was evaluated through either coupon weight loss tests or polarization resistance. Corrosion inhibitor aging was carried out in autoclaves emulating operating conditions, subsequently, gel permeation chromatography (GPC), total nitrogen and viscosity measurements were performed on the products before and after aging to establish the variation of their physical and chemical properties. Additionally, X-ray diffraction analysis (XRD) and energy dispersion spectroscopy (EDS) were used to identify corrosion products. From the study, an efficiency of 86% was obtained for a line inhibitor at a 45-PPM dosage (at 36 psi pCO{sub 2} and 0.006 psi of H{sub 2}S at 120 F), lowering its efficiency to 76% after precorroding the surface for three days. The presence of asphaltene may reduce the corrosion rate; however, the injection of a dispersant accelerates the corrosion process. No significant changes in efficiency and physical properties were observed during the evaluation of one of the compression-line inhibitor mixtures tested.

  14. Corrosion inhibitors for solar-heating and cooling

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1979-01-01

    Report describes results of tests conducted to evaluate abilities of 12 candidate corrosion inhibitors to protect aluminum, steel, copper, or stainless steel at typical conditions encountered in solar heating and cooling systems. Inhibitors are based on sodium salts including nitrates, borates, silicates, and phosphates.

  15. Corrosion inhibitors for solar-heating and cooling

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1979-01-01

    Report describes results of tests conducted to evaluate abilities of 12 candidate corrosion inhibitors to protect aluminum, steel, copper, or stainless steel at typical conditions encountered in solar heating and cooling systems. Inhibitors are based on sodium salts including nitrates, borates, silicates, and phosphates.

  16. Effect of temperature on the application of Myrmecodia Pendans extract for environmentally friendly corrosion inhibitor

    NASA Astrophysics Data System (ADS)

    Pradityana, Atria; Sulistijono, Winarto, Widiyono, Eddy; Luwar, Budi; Mursid, Mahirul

    2017-05-01

    One of the efforts to control the corrosion rate used is to add inhibitors. Corrosion is a a decrease in the quality of a material (metal) caused by a chemical reaction between the metal and its environment. The purpose of this study is to analyze the effect of temperature on the corrosive medium in the presence of plant, Myrmecodia Pendans extracts as an organic inhibitor. This study used a type of carbon steel APT 5L Grade B with temperature 30°C, 40°C, 50°C. Corrosive medium used was 1M HCl with varying concentrations of plant extracts Myrmecodia Pendans 100 to 500 mg I L. Maceration method is a method used for extracting plants, Myrmecodia Pendans. The effectiveness of the use of organic inhibitors Myrmecodia Pendans in acid known by some measurements. There are ETS and FTTR. From the results of of measurements carried out, the Myrmecodia Pendans extract able to reduce corrosion rate. The resulting best inhibition efficiency of 82,88% at 30°C temperature conditions and extract the addition of 500 mg I L. Protection system that occurs is an Myrmecodia Pendans extract form a passive film on the surface of the material so as to reduce the corrosive attack.

  17. Bonding-Compatible Corrosion Inhibitor for Rinsing Metals

    NASA Technical Reports Server (NTRS)

    Saunders, C. R.; Wurth, L. A.; Radar, A.

    2005-01-01

    A corrosion-inhibiting mixture of compounds has been developed for addition to the water used to rinse metal parts that have been cleaned with aqueous solutions in preparation for adhesive bonding of the metals to rubber and rubber-like materials. Prior to the development of this corrosion inhibitor, the parts (made, variously, of D6AC steel and 7075-T73 aluminum) were rinsed by deionized water, which caused corrosion in some places on the steel parts especially in such occluded places as sealing surfaces and threaded blind holes. An integral part of the particular cleaning process is the deposition of a thin layer of silicates and silane primers that increase the strength of the adhesive bond. The corrosion inhibitor is formulated, not only to inhibit corrosion of both D6AC steel and 7075- T73 aluminum, but also to either increase or at least not reduce the strength of the adhesive bond to be formed subsequently. The corrosion inhibitor is a mixture of sodium silicate and sodium tetraborate. The sodium silicate functions as both a corrosion inhibitor and a bond-strength promoter in association with the silane primers. The sodium tetraborate buffers the rinse solution at the optimum pH and functions as a secondary corrosion inhibitor for the steel. For a given application, the concentrations of sodium silicate and sodium tetraborate must be chosen in a compromise among the needs to inhibit corrosion of steel, inhibit corrosion of aluminum, and minimize cosmetic staining of both steel and aluminum. Concentrations of sodium silicate in excess of 150 parts of silicon per million parts of solution (ppm Si) have been determined to enhance inhibition of corrosion; unfortunately, because of the alkalinity of sodium silicate, even a small concentration can raise the pH of the rinse solution to such a level that aluminum becomes corroded despite the inhibiting effect. The pH of a solution that contains a high concentration of sodium silicate can be decreased by adding

  18. Modelling on corrosion inhibitor kinetics in carbon steel pipe used in oil industry

    NASA Astrophysics Data System (ADS)

    Hasmi, A. N.; Nuraini, N.; Wahyuningrum, D.; Sumarti, N.; Bunjali, B.

    2014-02-01

    A model to explain the kinetics of corrosion inhibitor is proposed here. The model is based on Transition State Theory. Our model has many similarities with Michelis-Menten Kinetics. The kinetics difference between uninhibited corrosion and inhibited corrosion is presented. Our model showed the inhibitor could suppress the corrosion rate.

  19. Benzotriazole a Corrosion Inhibitor for Antiques: Some Practical Surface Chemistry.

    ERIC Educational Resources Information Center

    Walker, Robert

    1980-01-01

    Describes the structure and inhibitive properties of Benzotriazole. The chemical may be employed as an inhibitor to reduce corrosion of articles during storage or display. It may be applied to copper and copper-based antiques as well as to silver and other metals. (Author/JN)

  20. Benzotriazole a Corrosion Inhibitor for Antiques: Some Practical Surface Chemistry.

    ERIC Educational Resources Information Center

    Walker, Robert

    1980-01-01

    Describes the structure and inhibitive properties of Benzotriazole. The chemical may be employed as an inhibitor to reduce corrosion of articles during storage or display. It may be applied to copper and copper-based antiques as well as to silver and other metals. (Author/JN)

  1. Effervescent Cationic Film Forming Corrosion Inhibitor Material and Process.

    DTIC Science & Technology

    1991-10-15

    1000 ppm in the volume of aliminum surface of a weapon in a launch tube on a seawater that floods the weapon tube. submarine with a corrosion inhibitor film, comprising: 20 * * * * * 25 30 35 40 45 50 55 a. 60 65

  2. Corrosion Inhibitors for Metals in Naval Environments

    DTIC Science & Technology

    1988-06-15

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

  3. Effect of B-Mo-W Complex Inhibitor on Corrosion of Mild Steel in 55% LiBr Solution

    NASA Astrophysics Data System (ADS)

    Li, Jielan; Liang, Chenghao; Huang, Naibao

    2015-11-01

    The inhibition effects of B-Mo-W complex inhibitor on corrosion of mild steel in 55% LiBr solution were investigated using weight-loss method, electrochemistry tests, SEM, EDX, and XRD. The ingredients of B-Mo-W complex inhibitor included organic phosphonic acid B, Na2MoO4, and Na2WO4. The results revealed that B-Mo-W complex inhibitor was capable of inhibiting the corrosion of mild steel in 55% LiBr solution, exhibiting high inhibition efficiencies around 97.7%. B-Mo-W complex inhibitor promoted the formation of a protective passive film composed of Fe, Mo, W, and O elements. The passive film decreased the corrosion rate, improved the electrochemistry performance, and enhanced anti-corrosion ability of mild steel.

  4. A corrosion control concept by scale engineering: a novel green inhibitor applied for high temperature and pressure aqueous supercritical CO2 systems

    SciTech Connect

    Jiabin, Han; Carey, James W; Zhang, Jinsuo

    2011-01-27

    Traditional corrosion inhibitors are bio-toxic chemicals with organic components that bond to the fresh metal surface and thus isolate them from corrosive environments. The shortcoming of these inhibitors is that they are less effective in high-temperature and high-pressure environments, and where corrosion scale is formed or particulates are deposited. In this paper, we describe a novel green inorganic inhibitor made of environmentally friendly and cost-effective geo-material that was developed for high-temperature and high-pressure environments, particularly under scale-forming conditions. It inhibits corrosion by enhancing the protectiveness of corrosion scale. In contrast to traditional corrosion inhibitors which are efficient for bare surface corrosion but not effective with scale, the novel inhibitor has no effect on bare surface corrosion but greatly improves corrosion inhibition under scale-formation conditions. This is because a homogeneous scale doped with inhibitor component forms. This enhanced corrosion scale demonstrated excellent protection against corrosion. In high-pressure CO{sub 2} systems (pCO{sub 2}=10 Mpa, T=50 C and [NaCl]=1 wt%) without inhibitor, the bare-surface corrosion rate decreases from ca. 10 mm/y to 0.3 mm/year due to formation of scale. Application of a six hundred ppm solution ofthe new inorganic inhibitor reduced the corrosion rate to 0.01 mm/year, an additional factor of 30. The current inhibitor product was designed for application to CO{sub 2} systems that form corrosion scale, including but not limited to oil and gas wells, offshore production of oil and gas, CO{sub 2} sequestration and enhanced geothermal production involving CO{sub 2}.

  5. Prediction aluminum corrosion inhibitor efficiency using artificial neural network (ANN)

    NASA Astrophysics Data System (ADS)

    Ebrahimi, Sh; Kalhor, E. G.; Nabavi, S. R.; Alamiparvin, L.; Pogaku, R.

    2016-06-01

    In this study, activity of some Schiff bases as aluminum corrosion inhibitor was investigated using artificial neural network (ANN). Hence, corrosion inhibition efficiency of Schiff bases (in any type) were gathered from different references. Then these molecules were drawn and optimized in Hyperchem software. Molecular descriptors generating and descriptors selection were fulfilled by Dragon software and principal component analysis (PCA) method, respectively. These structural descriptors along with environmental descriptors (ambient temperature, time of exposure, pH and the concentration of inhibitor) were used as input variables. Furthermore, aluminum corrosion inhibition efficiency was used as output variable. Experimental data were split into three sets: training set (for model building) and test set (for model validation) and simulation (for general model). Modeling was performed by Multiple linear regression (MLR) methods and artificial neural network (ANN). The results obtained in linear models showed poor correlation between experimental and theoretical data. However nonlinear model presented satisfactory results. Higher correlation coefficient of ANN (R > 0.9) revealed that ANN can be successfully applied for prediction of aluminum corrosion inhibitor efficiency of Schiff bases in different environmental conditions.

  6. pH Sensitive Microcapsules for Delivery of Corrosion Inhibitors

    NASA Technical Reports Server (NTRS)

    Li, Wenyan; Calle, Luz M.

    2006-01-01

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

  7. Behavior of aspartic acid as a corrosion inhibitor for steel

    SciTech Connect

    Kalota, D.J.; Silverman, D.C. )

    1994-02-01

    Corrosion inhibition of steel by aspartic acid (C[sub 4]H[sub 7]NO[sub 4]), an amino acid of low molecular weight, was found to depend strongly on pH. At a pH less than the ionization constant at [approximately]9.5 to 10 (measured at 25 C), C[sub 4]H[sub 7]NO[sub 4] appeared to accelerate corrosion. Above the pH, it acted as a corrosion inhibitor for steel. A specially constructed potential-pH diagram for iron (Fe) that incorporated C[sub 4]H[sub 7]NO[sub 4] showed the change in behavior was accompanied by the most stable thermodynamic state changing from an iron aspartate complex to iron oxide. Polymerized C[sub 4]H[sub 7]NO[sub 4] (polyaspartic acid) behaved in a similar manner. Some other amino acids of low molecular weight behaved similarly.

  8. Alkylaniline/formaldehyde co-oligomers as corrosion inhibitors

    SciTech Connect

    Bacskai, R.; Schroeder, A.H.

    1988-10-18

    This patent describes a method of inhibiting corrosion of a corrodible metal material in or around a well through which a corrosive fluid is produced, which comprises contacting the metal material with an effective amount of a corrosion inhibitor composition comprising the reaction product obtained by the acid-catalyzed oligomerization of (A) an alkylaniline having from 4 to 30 carbon atoms in the alkyl substituent, (B) formaldehyde, and (C) an aromatic compound selected from the group consisting of aniline, phenol, alkylphenol having from 6 to 30 carbon atoms in in the alkyl substituent, and an ethoxylated alkylphenol wherein R is alkyl of 6 to 24 carbon atoms, and n is an integer from 3 to 20.

  9. Application of hydrotalcites as corrosion-inhibiting pigments in organic coatings

    NASA Astrophysics Data System (ADS)

    Mahajanam, Sudhakar P. V.

    High strength aluminum alloys typically used in the aerospace industry are provided with coatings for corrosion protection. One of the coating layers is the primer, containing corrosion inhibiting pigments. Conventionally chromate pigments have been used but they are carcinogenic; so there is a need to develop environment-friendly alternatives that can match the corrosion inhibition of chromates. In this study, the use of hydrotalcites as corrosion-inhibiting pigments in organic coatings has been explored. Hydrotalcites are anion clays with excellent ion-exchange capabilities, and for this reason they have been used in industry as anion scavengers. Vanadates are excellent inhibitors of Al alloy corrosion. A Zn-Al-decavanadate hydrotalcite (HT-V) was synthesized and its ion exchange properties characterized. From instrumental neutron activation studies, it was determined that inhibitor release was a small fraction of the total inhibitor in the pigment. However, this was sufficient to provide appreciable corrosion inhibition to Al alloys during potentiodynamic polarization. Additionally, inhibitor release occurred even when these pigments were dispersed in epoxy resins and applied to Al alloys. A bare surface in close proximity to the coating was also inhibited from corrosion. Lastly, coatings containing the HT-V pigment performed well in a salt spray environment, protecting scribe corrosion up to 1000 h exposure. Blistering problems encountered during this test were overcome by silane additions to the coating, which improved adhesion and controlled blistering.

  10. Polypeptide Inhibitors of Mineral Scaling and Corrosion

    DTIC Science & Technology

    1989-06-01

    formation. A thermal method of synthesis of polyaspartate based on peptide bond formation in dry powders of aspartic acid at around 200 C was developed...peptides are based on natural protein inhibitors of mineral formation and generally are enriched in aspartic acid and phosphoserine. Specifically, the...AsP5 to AsP60 was synthesized by repetitive couplings of t-Boc-L- aspartic acid residues with B-carboxyl protection by O-benzyl linkage. A C-terminal

  11. Influence of an oil soluble inhibitor on microbiologically influenced corrosion in a diesel transporting pipeline.

    PubMed

    Muthukumar, N; Maruthamuthu, S; Mohanan, S; Palaniswamy, N

    2007-01-01

    Microbial degradation of the oil soluble corrosion inhibitor (OSCI) Baker NC 351 contributed to a decrease in inhibitor efficiency. Corrosion inhibition efficiency was studied by the rotating cage and flow loop methods. The nature of the biodegradation of the corrosion inhibitor was also analysed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry. The influence of bacterial activity on the degradation of the corrosion inhibitor and its influence on corrosion of API 5LX were evaluated using a weight loss technique and impedance studies. Serratia marcescens ACE2 and Bacillus cereus ACE4 can degrade aromatic and aliphatic hydrocarbons present in the corrosion inhibitor. The present study also discusses the demerits of the oil soluble corrosion inhibitors used in petroleum product pipeline.

  12. Water-soluble inhibitor on microbiologically influenced corrosion in diesel pipeline.

    PubMed

    Muthukumar, N; Maruthamuthu, S; Palaniswamy, N

    2006-12-01

    The effect of water-soluble corrosion inhibitor on the growth of bacteria and its corrosion inhibition efficiency were investigated. Corrosion inhibition efficiency was studied by rotating cage test and flow loop techniques. The nature of biodegradation of corrosion inhibitor was also analyzed by using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (NMR) and Gas chromatography and mass spectrometer (GC-MS). The bacterial isolates (Serratia marcescens ACE2, Bacillus cereus ACE4) have the capacity to degrade the aromatic and aliphatic hydrocarbon present in the corrosion inhibitor. The degraded products of corrosion inhibitor and bacterial activity determine the electrochemical behaviour of API 5LX steel. The influence of bacterial activity on degradation of corrosion inhibitor and its influence on corrosion of API 5LX have been evaluated by employing weight loss techniques and electrochemical studies. The main finding of this paper is that the water-soluble corrosion inhibitor is consumed by the microbial action, which contributes to the decrease in inhibitor efficiency. The present study also emphasis the importance of evaluation of water-soluble corrosion inhibitor in stagnant model (flow loop test) and discusses the demerits of the water-soluble corrosion inhibitors in petroleum product pipeline.

  13. Solderability preservation through the use of organic inhibitors

    SciTech Connect

    Sorensen, N.R.; Hosking, F.M.

    1994-12-01

    Organic inhibitors can be used to prevent corrosion of metals and have application in the electronics industry as solderability preservatives. We have developed a model to describe the action of two inhibitors (benzotriazole and imidazole) during the environmental aging and soldering process. The inhibitors bond with the metal surface and form a barrier that prevents or retards oxidation. At soldering temperatures, the metal-organic complex breaks down leaving an oxide-free metal surface that allows excellent wetting by molten solder. The presence of the inhibitor retards the wetting rate relative to clean copper, but provides a vast improvement relative to oxidized copper.

  14. Biodegradation of corrosion inhibitors and their influence on petroleum product pipeline.

    PubMed

    Rajasekar, Aruliah; Maruthamuthu, Sundaram; Palaniswamy, Narayanan; Rajendran, Annamalai

    2007-01-01

    The present study enlightens the role of Bacillus cereus ACE4 on biodegradation of commercial corrosion inhibitors (CCI) and the corrosion process on API 5LX steel. Bacillus cereus ACE4, a dominant facultative aerobic species was identified by 16S rDNA sequence analysis, which was isolated from the corrosion products of refined diesel-transporting pipeline in North West India. The effect of CCI on the growth of bacterium and its corrosion inhibition efficiency were investigated. Corrosion inhibition efficiency was studied by rotating cage test and the nature of biodegradation of corrosion inhibitors was also analyzed. This isolate has the capacity to degrade the aromatic and aliphatic hydrocarbon present in the corrosion inhibitors. The degraded products of corrosion inhibitors and bacterial activity determine the electrochemical behavior of API 5LX steel.

  15. Strategic Research: In-Tank Generation of Corrosion Inhibitors

    SciTech Connect

    Hobbs, D.T.

    2002-08-21

    Prevention of stress corrosion cracking and pitting corrosion in high-level waste (HLW) tanks requires the periodic addition of corrosion inhibitors, sodium hydroxide and sodium nitrite. These inhibitor ions can be generated electrochemically from the nitrate present in the waste. Thus, a continuously operated electrochemical reactor placed in the top of the tank could generate nitrite and hydroxide. In-tank generation would eliminate the need to continually add process chemicals resulting in cost savings associated with the procurement, pretreatment and disposal of these chemicals. Experiments examined whether both nitrite and hydroxide could be generated simultaneously from a simple waste simulant in a single electrolytic cell. Results indicated that hydroxide, but not nitrite, formed at a rate that would be effective for in-tank generation. Nitrate reduction proceeded beyond the production of nitrite to produce other nitrogen-containing products. We recommend additional testing to identify an optimum cathode material for nitrite production. Alternatively, the in-tank generator may feature a divided cell configuration or dual electrochemical cells in which one cell generates hydroxide and the second cell generates nitrite.

  16. The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

    PubMed

    Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

    2013-01-01

    The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01).

  17. Determining the Chemical Composition of Corrosion Inhibitor/Metal Interfaces with XPS: Minimizing Post Immersion Oxidation.

    PubMed

    Walczak, Monika S; Morales-Gil, Perla; Belashehr, Turia; Kousar, Kiran; Arellanes Lozada, Paulina; Lindsay, Robert

    2017-03-15

    An approach for acquiring more reliable X-ray photoelectron spectroscopy data from corrosion inhibitor/metal interfaces is described. More specifically, the focus is on metallic substrates immersed in acidic solutions containing organic corrosion inhibitors, as these systems can be particularly sensitive to oxidation following removal from solution. To minimize the likelihood of such degradation, samples are removed from solution within a glove box purged with inert gas, either N2 or Ar. The glove box is directly attached to the load-lock of the ultra-high vacuum X-ray photoelectron spectroscopy instrument, avoiding any exposure to the ambient laboratory atmosphere, and thus reducing the possibility of post immersion substrate oxidation. On this basis, one can be more certain that the X-ray photoelectron spectroscopy features observed are likely to be representative of the in situ submerged scenario, e.g. the oxidation state of the metal is not modified.

  18. Determining the Chemical Composition of Corrosion Inhibitor/Metal Interfaces with XPS: Minimizing Post Immersion Oxidation

    PubMed Central

    Walczak, Monika S.; Morales-Gil, Perla; Belashehr, Turia; Kousar, Kiran; Arellanes Lozada, Paulina; Lindsay, Robert

    2017-01-01

    An approach for acquiring more reliable X-ray photoelectron spectroscopy data from corrosion inhibitor/metal interfaces is described. More specifically, the focus is on metallic substrates immersed in acidic solutions containing organic corrosion inhibitors, as these systems can be particularly sensitive to oxidation following removal from solution. To minimize the likelihood of such degradation, samples are removed from solution within a glove box purged with inert gas, either N2 or Ar. The glove box is directly attached to the load-lock of the ultra-high vacuum X-ray photoelectron spectroscopy instrument, avoiding any exposure to the ambient laboratory atmosphere, and thus reducing the possibility of post immersion substrate oxidation. On this basis, one can be more certain that the X-ray photoelectron spectroscopy features observed are likely to be representative of the in situ submerged scenario, e.g. the oxidation state of the metal is not modified. PMID:28362363

  19. cap alpha. -Alkenylphenones - A new class of acid corrosion inhibitors

    SciTech Connect

    Frenier, W.W.; Growcock, F.B.; Lopp, V.R. )

    1988-09-01

    In this paper, a new class of corrosion inhibitors for steel in strong HCI is described. When formulated with small amounts of surfactants, ..cap alpha..-Alkenylphenones provide excellent protection for oilfield steel in contact with strong HCI (up to 28%). The protection levels are similar to, and sometimes superior to, those provided by alkynols. In 15% HCI, benzylallyl alcohol (BAA) appears to be a common intermediate, i.e., in the acid after 24 h when any of the four different phenyl ketones are used. Poly(phenylvinyl ketone) (PPVK), which could form on the surface from reaction of absorbed BAA, was the major component of the thin surface film after corrosion tests with the four ketones.

  20. Field trials for corrosion inhibitor selection and optimization, using a new generation of electrical resistance probes

    SciTech Connect

    Ridd, B.; Blakset, T.J.; Queen, D.

    1998-12-31

    Even with today`s availability of corrosion resistant alloys, carbon steels protected by corrosion inhibitors still dominate the material selection for pipework in the oil and gas production. Even though laboratory screening tests of corrosion inhibitor performance provides valuable data, the real performance of the chemical can only be studied through field trials which provide the ultimate test to evaluate the effectiveness of an inhibitor under actual operating conditions. A new generation of electrical resistance probe has been developed, allowing highly sensitive and immediate response to changes in corrosion rates on the internal environment of production pipework. Because of the high sensitivity, the probe responds to small changes in the corrosion rate, and it provides the corrosion engineer with a highly effective method of optimizing the use of inhibitor chemicals resulting in confidence in corrosion control and minimizing detrimental environmental effects.

  1. Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating

    NASA Astrophysics Data System (ADS)

    R. V., Lakshmi; S. T., Aruna; Sampath, S.

    2017-01-01

    The present work provides a comparative study on the corrosion protection efficiency of defect free sol-gel hybrid coating containing ceria nanoparticles and cerium nitrate ions as corrosion inhibitors. Less explored organically modified alumina-silica hybrid sol-gel coatings are synthesized from 3-glycidoxypropyltrimethoxysilane and aluminium-tri-sec-butoxide. The microemulsion derived nanoparticles and the hybrid coatings are characterized and compared with coatings containing cerium nitrate. Corrosion inhibiting capability is assessed using electrochemical impedance spectroscopy. Scanning Kelvin probe measurements are also conducted on the coatings for identifying the apparent corrosion prone regions. Detailed X-ray photoelectron spectroscopy (XPS) analysis is carried out to comprehend the bonding and corrosion protection rendered by the hybrid coatings.

  2. Ceria nanoparticles vis-à-vis cerium nitrate as corrosion inhibitors for silica-alumina hybrid sol-gel coating

    NASA Astrophysics Data System (ADS)

    Lakshmi, R. V.; Aruna, S. T.; Sampath, S.

    2017-01-01

    The present work provides a comparative study on the corrosion protection efficiency of defect free sol-gel hybrid coating containing ceria nanoparticles and cerium nitrate ions as corrosion inhibitors. Less explored organically modified alumina-silica hybrid sol-gel coatings are synthesized from 3-glycidoxypropyltrimethoxysilane and aluminium-tri-sec-butoxide. The microemulsion derived nanoparticles and the hybrid coatings are characterized and compared with coatings containing cerium nitrate. Corrosion inhibiting capability is assessed using electrochemical impedance spectroscopy. Scanning Kelvin probe measurements are also conducted on the coatings for identifying the apparent corrosion prone regions. Detailed X-ray photoelectron spectroscopy (XPS) analysis is carried out to comprehend the bonding and corrosion protection rendered by the hybrid coatings.

  3. [Use of corrosion inhibitors during the sterilization and disinfection of medical instruments].

    PubMed

    Talalina, A S; Kochanova, L G; Anan'eva, A I; Romanova, A A

    1984-01-01

    The search of corrosion inhibitors reducing the corrosive action of the sterilizing and disinfecting media has been performed in order to protect instruments made of metals against corrosion during these processes. The program of the investigations includes potentiodynamic and potentiostatic measurements and full-scale tests. The infection of the sodium benzoate or potassium gluconate into the disinfecting chloramine solution and sterilizing hydrogene peroxide solution has been shown to improve the resistance to the corrosion for medical instruments made of carbon steel.

  4. Improvement of the linear polarization resistance method for testing steel corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    Faritov, A. T.; Rozhdestvenskii, Yu. G.; Yamshchikova, S. A.; Minnikhanova, E. R.; Tyusenkov, A. S.

    2016-11-01

    The linear polarization resistance method is used to improve the technique of corrosion control in liquid conducting according to GOST 9.514-99 (General Corrosion and Aging Protection System. Corrosion Inhibitors for Metals in Water Systems. Electrochemical Method of Determining the Protective Ability). Corrosion monitoring is shown to be performed by electronic devices with real-time data transfer to industrial controllers and SCADA systems.

  5. Magnetic resonance microimaging of pore freezing in cement: Effect of corrosion inhibitor

    NASA Astrophysics Data System (ADS)

    Holly, R.; Tritt-Goc, J.; Pislewski, N.; Hansson, C. M.; Peemoeller, H.

    2000-12-01

    Single-point magnetic resonance imaging is applied to study the freezing behavior of white cement paste with and without a Ca(NO2)2 based corrosion inhibitor. Pore size distributions are determined from consideration of the evaporable water content. This represents a unique study into the effect of a corrosion inhibitor on the final cement product. It is found that with the addition of a Ca(NO2)2 based corrosion inhibitor a significant reduction of pores between 3 and 10 nm results, producing a considerably coarser pore structure. A dramatic increase in capillary pores of radii larger than 30 nm is also observed in the cement with the inhibitor and is expected to lead to an increased movement of corrosive agents into the concrete when compared to concrete without the corrosion inhibitor.

  6. Langmuir adsorption isotherm analysis on the addition of Myrmecodia Pendans extract as a corrosion inhibitor with a variety of corrosive media

    NASA Astrophysics Data System (ADS)

    Pradityana, Atria; Sulistijono, Subowo, Suhariyanto, Subiyanto, Hari; Rusdiyana, Liza

    2017-05-01

    In this study, the corrosion process was done by potentiodynamic polarization method on API 5L Grade B. Variations corrosion media used were NaCl 3,5%, HCl 1 M and H2SO4 1 M. Organic Inhibitors used are plant Myrmecodia Pendans, while the concentration of the extract used were 100-500 mg / L (multiples of 100 mg / L). In this study, the mechanism of adsorption equation model used is Langmuir. This study aims to determine appropriate corrosive media followed the Langmuir adsorption isotherm when added to extracts of Myrmecodia Pendans as a corrosion inhibitor. The value of free energy of the system have obtained from the adsorption isotherm models. With the known value of free energy, it can be seen whether the adsorption occurs in physics or chemistry. This relates to the surface protective layer formed on the surface adsorption extract. The results showed that the corrosion in 3.5% NaCl solution that follows the Langmuir method.

  7. Effect of Chromate and Chromate-Free Organic Coatings on Corrosion Fatigue of an Aluminum Alloy

    DTIC Science & Technology

    2012-02-20

    the vicinity. Bentonite is hydrated alumino silicate clay primarily composed of the smectite class mineral montmorillonite [73]. The ideal formula for...used as inhibitors. It was studied also bentonite clay , which contains 99% of montmorillonite. The reason of choosing bentonite as aluminum alloy...natural bentonite , natural zeolite and Ca-ion exchanged and Zn-ion exchanged zeolites were studied as aluminum alloy corrosion inhibitors in organic

  8. Electrochemical and analytical characterization of three corrosion inhibitors of steel in simulated concrete pore solutions

    NASA Astrophysics Data System (ADS)

    Shi, Jin-Jie; Sun, Wei

    2012-01-01

    Corrosion inhibitors for steel, such as sodium phosphate (Na3PO4), sodium nitrite (NaNO2), and benzotriazole (BTA), in simulated concrete pore solutions (saturated Ca(OH)2) were investigated. Corrosion behaviors of steel in different solutions were studied by means of corrosion potential ( E corr), linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization (PDP). A field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray analysis (EDXA) was used for observing the microstructures and morphology of corrosion products of steel. The results indicate that, compared with the commonly used nitrite-based inhibitors, Na3PO4 is not a good inhibitor, while BTA may be a potentially effective inhibitor to prevent steel from corrosion in simulated concrete pore solutions.

  9. Further advanced in the development of environmentally acceptable corrosion inhibitors

    SciTech Connect

    Martin, R.L.; Alink, B.A.; McMahon, J.A.; Weare, R.

    1999-11-01

    The environmental fate of specialty chemicals used in petroleum recovery processes has received increased attention in recent years. The laboratory has contributed to early advances in this field. This paper outlines further systematic studies. The influences of alkylation, starting amine type, and acid chain length on imidazoline properties were studied in addition to the properties of blends. The properties considered were corrosion inhibition, biodegradability, marine organism toxicity, octanol/water partitioning, and vapor pressure. A cross section of field test and application results is included.

  10. The effect of corrosion inhibitors on microbial communities associated with corrosion in a model flow cell system.

    PubMed

    Duncan, Kathleen E; Perez-Ibarra, Beatriz Monica; Jenneman, Gary; Harris, Jennifer Busch; Webb, Robert; Sublette, Kerry

    2014-01-01

    A model flow cell system was designed to investigate pitting corrosion in pipelines associated with microbial communities. A microbial inoculum producing copious amounts of H₂S was enriched from an oil pipeline biofilm sample. Reservoirs containing a nutrient solution and the microbial inoculum were pumped continuously through six flow cells containing mild steel corrosion coupons. Two cells received corrosion inhibitor "A", two received corrosion inhibitor "B", and two ("untreated") received no additional chemicals. Coupons were removed after 1 month and analyzed for corrosion profiles and biofilm microbial communities. Coupons from replicate cells showed a high degree of similarity in pitting parameters and in microbial community profiles, as determined by 16S rRNA gene sequence libraries but differed with treatment regimen, suggesting that the corrosion inhibitors differentially affected microbial species. Viable microbial biomass values were more than 10-fold higher for coupons from flow cells treated with corrosion inhibitors than for coupons from untreated flow cells. The total number of pits >10 mils diameter and maximum pitting rate were significantly correlated with each other and the total number of pits with the estimated abundance of sequences classified as Desulfomicrobium. The maximum pitting rate was significantly correlated with the sum of the estimated abundance of Desulfomicrobium plus Clostridiales, and with the sum of the estimated abundance of Desulfomicrobium plus Betaproteobacteria. The lack of significant correlation with the estimated abundance of Deltaproteobacteria suggests not all Deltaproteobacteria species contribute equally to microbiologically influenced corrosion (MIC) and that it is not sufficient to target one bacterial group when monitoring for MIC.

  11. New corrosion inhibitor acrylamide methyl ether for mild steel in 1 M HCl

    NASA Astrophysics Data System (ADS)

    Ma, Xinyu; Jiang, Xiaohui; Xia, Shuwei; Shan, Mingli; Li, Xia; Yu, Liangmin; Tang, Qunwei

    2016-05-01

    Pursuit of good inhibition performance has been a persistent objective for advanced inhibitor industry. Here we demonstrate the experimental realization of a new corrosion inhibitor acrylamide methyl ether (AAME) from N-Methylol acrylamide (N-MAM) for mild steel in 1 M HCl. The resultant adsorption films have inhibition efficiency as high as 96.2%. Moreover, a theoretical investigation is also launched to demonstrate the potential mechanism behind the promising corrosion behaviors. This work represents a significant step forward, as it demonstrates how to make scalable AAME inhibitors as well as to enhance inhibition performances for high-efficiency and cost-effective corrosion inhibition platforms.

  12. Studies on Corrosion Prevention of Mardan Connectors by Organic Coatings.

    DTIC Science & Technology

    1980-06-09

    because of its previous use as a lubricant in electronic components (17). Sodium hexametaphosphate is a corrosion-preventive com- pound that is...continued) 18 Table 1 (continued) P4P3E NAHEX Code MCS 210 Sodium Hexametaphosphate Mfgrs. Name High temperature lubri- Corrosion Inhibitor cant Purpose...Polyphenyl ether, 4P3E Sodium hexametaphosphate Composition - Solvent Additives Fluid Solid, dissolved in H20 Physical State Swab Swab Applic. Method Fluid

  13. Natural Corrosion Inhibitors for Steel Reinforcement in Concrete — a Review

    NASA Astrophysics Data System (ADS)

    Raja, Pandian Bothi; Ghoreishiamiri, Seyedmojtaba; Ismail, Mohammad

    2015-04-01

    Reinforced concrete is one of the widely used construction materials for bridges, buildings, platforms and tunnels. Though reinforced concrete is capable of withstanding a large range of severe environments including marine, industrial and alpine conditions, there are still a large number of failures in concrete structures for many reasons. Either carbonation or chloride attack is the main culprit which is due to depassivation of reinforced steel and subsequently leads to rapid steel corrosion. Among many corrosion prevention measures, application of corrosion inhibitors play a vital role in metal protection. Numerous range of corrosion inhibitors were reported for concrete protection that were also used commercially in industries. This review summarizes the application of natural products as corrosion inhibitors for concrete protection and also scrutinizes various factors influencing its applicability.

  14. What determines the inhibition effectiveness of ATA, BTAH, and BTAOH corrosion inhibitors on copper?

    PubMed

    Kokalj, Anton; Peljhan, Sebastijan; Finsgar, Matjaz; Milosev, Ingrid

    2010-11-24

    Three corrosion inhibitors for copper-3-amino-1,2,4-triazole (ATA), benzotriazole (BTAH), and 1-hydroxybenzotriazole (BTAOH)-were investigated by corrosion experiments and atomistic computer simulations. The trend of corrosion inhibition effectiveness of the three inhibitors on copper in near-neutral chloride solution is determined experimentally as BTAH ≳ ATA ≫ BTAOH. A careful analysis of the results of computer simulations based on density functional theory allowed to pinpoint the superior inhibiting action of BTAH and ATA as a result of their ability to form strong N-Cu chemical bonds in deprotonated form. While these bonds are not as strong as the Cl-Cu bonds, the presence of solvent favors the adsorption of inhibitor molecules onto the surface due to stronger solvation of the Cl(-) anions. Moreover, benzotriazole displays the largest affinity among the three inhibitors to form intermolecular aggregates, such as [BTA-Cu](n) polymeric complex. This is another factor contributing to the stability of the protective inhibitor film on the surface, thus making benzotriazole an outstanding corrosion inhibitor for copper. These findings cannot be anticipated on the basis of inhibitors' molecular electronic properties alone, thus emphasizing the importance of a rigorous modeling of the interactions between the components of the corrosion system in corrosion inhibition studies.

  15. Molecular dynamics simulation of corrosion mitigation of iron in lead-bismuth eutectic using nitrogen as corrosion inhibitor

    NASA Astrophysics Data System (ADS)

    Arkundato, Artoto; Su'ud, Zaki; Sudarko; Hasan, Mohammad; Celino, Massimo

    2015-06-01

    The corrosion of structural materials used in fast nuclear reactor design is a current major problem. It is due to the use of liquid metal as a coolant candidate in the heat transfer system. The liquid metal as lead-bismuth eutectic was found to make high corrosion to structural material as steel. One of the solutions of this problem is to inject some inhibitor into liquid metal. In this current work we simulate the effect of nitrogen injection as inhibitor candidate. The simulation will predict the proper concentration of injected nitrogen and also observe the microscopic structure of the material before and after injection to know the ability of nitrogen as an inhibitor. The simulation follows the molecular dynamics method and for preliminary study we use iron material rather than steel. We also use lennard-jones potential for simplification of the study. It is from our simulation we see nitrogen shows better corrosion mitigation compare with oxygen as in our previous study. The effective inhibition can be achieved by injecting at least 0.056wt.% nitrogen. This amount seems to be able to reduce the corrosion level of iron till about 99.5% for high corrosion at temperature 750 °C.

  16. Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

    NASA Astrophysics Data System (ADS)

    Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin; Othman, Norinsan Kamil

    2014-09-01

    Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm. Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.

  17. Tannin bark Melalauca cajuputi powell (gelam) as green corrosion inhibitor of mild steel

    SciTech Connect

    Talib, Nur Atiqah Abu; Zakaria, Sarani; Hua, Chia Chin; Othman, Norinsan Kamil

    2014-09-03

    Tannin was extracted from gelam bark and used to produce corrosion inhibitor for mild steel. Tannin was extracted from gelam bark using 70% aqueous acetone for 6 hour. Tannin powder was characterization using fourier transform infrared spectroscopy to analyse chemical component in tannin and Scanning electron microscope (SEM) for tannin physical structure. The tannin effect on the corrosion inhibition of mild steel has been investigated in 1Mol HCl solution for 6 hour followed ASTM. The weight loss method were applied to study the mild steel corrosion behavior in the present and absend of different concentration of tannin (250, 300, 350)ppm. Tannin act good inhibitor as corrosion inhibitor for mild steel in acid medium. Surface morphology of carbon steel with and without inhibitor was investigated by scanning electron microscopy.

  18. Protection of bronze artefacts through polymeric coatings based on nanocarriers filled with corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    de Luna, Martina Salzano; Buonocore, Giovanna; Di Carlo, Gabriella; Giuliani, Chiara; Ingo, Gabriel M.; Lavorgna, Marino

    2016-05-01

    Protective coatings based on polymers synthesized from renewable sources (chitosan or an amorphous vinyl alcohol based polymer) have been prepared for the protection of bronze artifacts from corrosion. Besides acting as an effective barrier against corrosive species present in the environment, the efficiency of the coatings has been improved by adding corrosion inhibitor compounds (benzotriazole or mercaptobenzothiazole) to the formulations. The liquid medium of the formulations has been carefully selected looking at maximizing the wettability on the bronze substrate and optimizing the solvent evaporation rate. The minimum amount of inhibitor compounds has been optimized by performing accelerated corrosion tests on coated bronze substrates. The inhibitors have been directly dissolved in the coating-forming solutions and/or introduced by means of nanocarriers, which allow to control the release kinetics. The free dissolved inhibitor molecules immediately provide a sufficient protection against corrosion. On the other hand, the inhibitor molecules contained in the nanocarriers serve as long-term reservoir, which can be activated by external corrosion-related stimuli in case of particularly severe conditions. Particular attention has been paid to other features which affect the coating performances. Specifically, the adhesion of the protective polymer layer to the bronze substrate has been assessed, as well as its permeability properties and transparency, the latter being a fundamental feature of protective coating for cultural heritages. Finally, the protective efficiency of the produced smart coatings has been assessed through accelerated corrosion tests.

  19. Effect of Corrosion Inhibitors on In Situ Leak Repair by Precipitation of Calcium Carbonate in Potable Water Pipelines.

    PubMed

    Wang, Fei; Devine, Christina L; Edwards, Marc A

    2017-08-01

    Corrosion inhibitors can affect calcium carbonate precipitation and associated in situ and in-service water distribution pipeline leak repair via clogging. Clogging of 150 μm diameter leak holes represented by glass capillary tubes, in recirculating solutions that are supersaturated with calcite (Ωcalcite = 13), demonstrated that Zn, orthophosphate, tripolyphosphate, and hexametaphosphate corrosion/scaling inhibitors hinder clogging but natural organic matter (NOM) has relatively little impact. Critical concentrations of phosphates that could inhibit leak repair over the short-term in one water tested were: tripolyphophate (0.05 mg/L as P) < hexametaphosphate (0.1 mg/L) < orthophosphate (0.3 mg/L). Inhibitor blends (Zn+orthophosphate and Zn+NOM+orthophosphate) had stronger inhibitory effects compared to each inhibitor (Zn, orthophosphate or NOM) alone, whereas Zn+NOM showed a lesser inhibitory effect than its individual component (NOM) alone due to formation of smaller CaCO3 particles with a much more negative zeta-potential. Overall, increased dosing of corrosion inhibitors is probably reducing the likelihood of scaling and in-service leak repair via clogging with calcium carbonate solids in potable water systems.

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

    NASA Astrophysics Data System (ADS)

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

    1999-02-01

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

  1. Investigation of ginkgo biloba leave extracts as corrosion and Oil field microorganism inhibitors

    PubMed Central

    2013-01-01

    Ginkgo biloba (Ginkgoaceae), originating from China, now distributes all over the world. Wide application of Ginkgo biloba extracts is determined by the main active substances, flavonoids and terpenoids, which indicates its extracts suitable to be used as an effective corrosion inhibitor. The extracts of Ginkgo biloba leave have been investigated on the corrosion inhibition of Q235A steel with weight loss and potentiodynamic polarisation techniques. The inhibition efficiency of the extracts varies with extract concentration. The extracts inhibit corrosion mainly by adsorption mechanism. Potentiodynamic polarisation studies show that extracts are mixed type inhibitors. The antibacterial activity of the extracts against oil field microorganism (SRB, IB and TGB) was also investigated. PMID:23651921

  2. Microbiologically Influenced Corrosion: Causative Organisms and Mechanisms

    DTIC Science & Technology

    2012-01-31

    natural iron oxyhydroxide biominerali/.ation products, Science 289 751-754. Beech IB and Cheung CWS (1995) Interactions of exopolymers produced by...Girasole M. Fra/.er BH, Nesterova MV. Fakra S and Banfield JF(2004)The role of microbial polymers in template mineral growth. Science 303 1656-2658. (hau... enviromental composition as a potential method for reversing microbiologically influenced corrosion, Corrosion (NAC’E) International. Houston. Texas

  3. Comparative Study on Corrosion Protection of Reinforcing Steel by Using Amino Alcohol and Lithium Nitrite Inhibitors.

    PubMed

    Lee, Han-Seung; Ryu, Hwa-Sung; Park, Won-Jun; Ismail, Mohamed A

    2015-01-14

    In this study, the ability of lithium nitrite and amino alcohol inhibitors to provide corrosion protection to reinforcing steel was investigated. Two types of specimens-reinforcing steel and a reinforced concrete prism that were exposed to chloride ion levels resembling the chloride attack environment-were prepared. An autoclave accelerated corrosion test was then conducted. The variables tested included the chloride-ion concentration and molar ratios of anti-corrosion ingredients in a CaOH₂-saturated aqueous solution that simulated a cement-pore solution. A concentration of 25% was used for the lithium nitrite inhibitor LiNO₂, and an 80% solution of dimethyl ethanolamine ((CH₃)₂NCH₂CH₂OH, hereinafter DMEA) was used for the amino alcohol inhibitor. The test results indicated that the lithium nitrite inhibitor displayed anti-corrosion properties at a molar ratio of inhibitor of ≥0.6; the amino alcohol inhibitor also displayed anti-corrosion properties at molar ratios of inhibitor greater than approximately 0.3.

  4. Comparative Study on Corrosion Protection of Reinforcing Steel by Using Amino Alcohol and Lithium Nitrite Inhibitors

    PubMed Central

    Lee, Han-Seung; Ryu, Hwa-Sung; Park, Won-Jun; Ismail, Mohamed A.

    2015-01-01

    In this study, the ability of lithium nitrite and amino alcohol inhibitors to provide corrosion protection to reinforcing steel was investigated. Two types of specimens—reinforcing steel and a reinforced concrete prism that were exposed to chloride ion levels resembling the chloride attack environment—were prepared. An autoclave accelerated corrosion test was then conducted. The variables tested included the chloride-ion concentration and molar ratios of anti-corrosion ingredients in a CaOH2-saturated aqueous solution that simulated a cement-pore solution. A concentration of 25% was used for the lithium nitrite inhibitor LiNO2, and an 80% solution of dimethyl ethanolamine ((CH3)2NCH2CH2OH, hereinafter DMEA) was used for the amino alcohol inhibitor. The test results indicated that the lithium nitrite inhibitor displayed anti-corrosion properties at a molar ratio of inhibitor of ≥0.6; the amino alcohol inhibitor also displayed anti-corrosion properties at molar ratios of inhibitor greater than approximately 0.3. PMID:28787936

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

    PubMed

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

    2015-01-01

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

  6. Inhibitor protection of metals at the corrosion fatigue crack growth stage

    SciTech Connect

    Panasyuk, V.V.; Ratych, L.V.

    1995-04-01

    Previously published results of tests on the influence of corrosion inhibitors on electrochemical conditions at the corrosion fatigue crack (CFC) tip and specimen surface and on the cyclic corrosion crack growth resistance (CGR) of 0.44% carbon (C)-chromium (Cr) steel in water were reviewed. A direct interrelation has been shown to exist between electrochemical conditions at the CFC tip and the cyclic corrosion CGR of steel in inhibited and noninhibited water. On this basis, a methodology for evaluating inhibitor effectiveness in the presence of a crack in a structural element was developed. The electrochemical criteria for assessing the intensity of local anodic dissolution (LAD) and hydrogen embrittlement (HE) of a metal at the CFC tip were proposed. Averaged electrochemical parameters were used to develop methods of comparing different inhibitors more effectively and of determining optimal concentrations.

  7. Interfacial modification of clay nanotubes for the sustained release of corrosion inhibitors.

    PubMed

    Joshi, Anupam; Abdullayev, Elshad; Vasiliev, Alexandre; Volkova, Olga; Lvov, Yuri

    2013-06-18

    Long-lasting anticorrosive coatings for steel have been developed on the basis of halloysite nanotubes loaded with three corrosion inhibitors: benzotriazole, mercaptobenzothiazole, and mercaptobenzimidazole. The inhibitors' loaded tubes were admixed at 5-10 wt % to oil-based alkyd paint providing sustained agent release and corrosion healing in the coating defects. The slow 20-30 h release of the inhibitors at defect points caused a remarkable improvement in the anticorrosion efficiency of the coatings. Further time expansion of anticorrosion agent release has been achieved by the formation of release stoppers at nanotube ends with urea-formaldehyde copolymer and copper-inhibitor complexation. The corrosion protection efficiency was tested on ASTM A366 steel plates in a 0.5 M NaCl solution with the microscanning of corrosion current development by microscopy inspection and studying paint adhesion. The best protection was found using halloysite/mercaptobenzimidazole and benzotriazole inhibitors. Stopper formation with urea-formaldehyde copolymer provided an additional increase in corrosion efficiency as a result of the longer release of inhibitors.

  8. Evaluation of Preservative Engine Oil Containing Vapor-Phase Corrosion Inhibitor and a Simplified Engine Preservation Technique

    DTIC Science & Technology

    1990-12-01

    AD-A240 100 EVALUATIONS OF PRESERVATIVE ENGINE OIL CONTAINING VAPOR-PHASE CORROSION INHIBITOR AND A SIMPLIFIED ENGINE PRESERVATION TECHNIQUE INTERIM...22060-5606 62786 AH20 123 11. TITLE (Include Security Classtfication) Evaluations of Preservative Engine Oil Containing Vapor-Phase Corrosion Inhibitor...the feasibility of adding a vapor-phase corrosion inhibitor (VCI) component to improve the preservation performance of MIL-L-21260 and (2) to evaluate

  9. Eco-Friendly Inhibitors for Copper Corrosion in Nitric Acid: Experimental and Theoretical Evaluation

    NASA Astrophysics Data System (ADS)

    Savita; Mourya, Punita; Chaubey, Namrata; Singh, V. K.; Singh, M. M.

    2016-02-01

    The inhibitive performance of Vitex negundo, Adhatoda vasica, and Saraka asoka leaf extracts on corrosion of copper in 3M HNO3 solution was investigated using gravimetric, potentiodynamic polarization, and electrochemical impedance spectroscopic techniques. Potentiodynamic polarization studies indicated that these extracts act as efficient and predominantly cathodic mixed inhibitor. Thermodynamic parameters revealed that the adsorption of these inhibitors on copper surface was spontaneous, controlled by physiochemical processes and occurred according to the Langmuir adsorption isotherm. AFM examination of copper surface confirmed that the inhibitor prevented corrosion by forming protective layer on its surface. The correlation between inhibitive effect and molecular structure was ascertained by density functional theory data.

  10. The microwave assisted synthesis of 1-alkyl-3-methylimidazolium bromide as potential corrosion inhibitor toward carbon steel in 1 M HCl solution saturated with carbon dioxide

    NASA Astrophysics Data System (ADS)

    Pasasa, Norman Vincent A.; Bundjali, Bunbun; Wahyuningrum, Deana

    2015-09-01

    Injection of corrosion inhibitor into the fluid current of oil and gas pipelines is an effective way to mitigate corrosion rate on the inner-surface parts of pipelines, especially carbon steel pipelines. In this research, two alkylimidazolium ionic liquids, 1-decyl-3-methylimidazolium bromide (IL1) and 1-dodecyl-3-methylimidazolium bromide (IL2) have been synthesized and studied as a potential corrosion inhibitor towards carbon steel in 1 M HCl solution saturated with carbon dioxide. IL1 and IL2 were synthesized using microwave assisted organic synthesis (MAOS) method. Mass Spectrometry analysis of IL1 and IL2 showed molecular mass [M-H+] peak at 223.2166 and 251.2484, respectively. The FTIR,1H-NMR and 13C-NMR spectra confirmed that IL1 and IL2 were successfully synthesized. Corrosion inhibition activity of IL1 and IL2 were determined using weight loss method. The results showed that IL1 and IL2 have the potential as good corrosion inhibitors with corrosion inhibition efficiency of IL1 and IL2 are 96.00% at 100 ppm (343 K) and 95.60% at 50 ppm (343 K), respectively. The increase in the concentration of IL1 and IL2 tends to improve their corrosion inhibition activities. Analysis of the data obtained from the weight loss method shows that the adsorption of IL1 and IL2 on carbon steel is classified into chemisorption which obeys Langmuir's adsorption isotherm.

  11. Environmentally Compatible Vapor-Phase Corrosion Inhibitor for Space Shuttle Hardware

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.; McCool, Alex (Technical Monitor)

    2001-01-01

    USA-SRB Element is responsible for the assembly and refurbishment of the non-motor components of the SRB as part of Space Shuttle. Thrust Vector Control (TVC) frames structurally support components of the TVC system located in the aft skirt of the SRB. TVC frames are exposed to the seacoast environment after refurbishment and, also, to seawater immersion after splashdown, and during tow-back to CCAFS-Hangar AF refurbishment facilities. During refurbishment operations it was found that numerous TVC frames were experiencing internal corrosion and coating failures, both from salt air and seawater intrusions. Inspectors using borescopes would visually examine the internal cavities of the complicated aluminum alloy welded tubular structure. It was very difficult for inspectors to examine cavity corners and tubing intersections and particularly, to determine the extent of the corrosion and coating anomalies. Physical access to TVC frame internal cavities for corrosion removal and coating repair was virtually impossible, and an improved method using a Liquid (water based) Vapor-phase Corrosion Inhibitor (LVCI) for preventing initiation of new corrosion, and mitigating and/or stopping existing corrosion growth was recommended in lieu of hazardous paint solvents and high VOC/solvent based corrosion inhibitors. In addition, the borescopic inspection method used to detect corrosion, and/or coating anomalies had severe limitations because of part geometry, and an improved non-destructive inspection (NDI) method using Neutron Radiography (N-Ray) was also recommended.

  12. Environmentally Compatible Vapor-Phase Corrosion Inhibitor for Space Shuttle Hardware

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.; Martin, David (Technical Monitor)

    2002-01-01

    USA-SRB Element is responsible for the assembly and refurbishment of the non-motor components of the SRB as part of Space Shuttle. Thrust Vector Control (TVC) frames structurally support components of the TVC system located in the aft skirt of the SRB (Solid Rocket Booster). TVC frames are exposed to the seacoast environment after refurbishment and, also, to seawater immersion after splashdown, and during tow-back to CCAFS-Hangar AF refurbishment facilities. During refurbishment operations it was found that numerous TVC frames were experiencing internal corrosion and coating failures, both from salt air and seawater intrusions. Inspectors using borescopes would visually examine the internal cavities of the complicated aluminum alloy welded tubular structure. It was very difficult for inspectors to examine cavity corners and tubing intersections and particularly. to determine the extent of the corrosion and coating anomalies. Physical access to TVC frame internal cavities for corrosion removal and coating repair was virtually impossible, and an improved method using a Liquid (water based) Vapor-phase Corrosion Inhibitor (LVCI) for preventing initiation of new corrosion, and mitigating and/or stopping existing corrosion growth was recommended in lieu of hazardous paint solvents and high VOC/solvent based corrosion inhibitors. In addition, the borescopic inspection method used to detect corrosion, and/or coating anomalies had severe limitations because of part geometry, and an improved non-destructive inspection (NDI) method using Neutron Radiography (N-Ray) was also recommended.

  13. Environmentally Compatible Vapor-Phase Corrosion Inhibitor for Space Shuttle Hardware

    NASA Technical Reports Server (NTRS)

    Novak, Howard L.; Hall, Phillip B.

    2003-01-01

    USA-SRB Element is responsible for the assembly and refurbishment of the non-motor components of the SRB as part of Space Shuttle. Thrust Vector Control (TVC) frames structurally support components of the TVC system located in the aft skirt of the SRB. TVC frames are exposed to the seacoast environment after refurbishment and, also, to seawater immersion after splashdown, and during tow-back to CCAFS-Hangar AF refurbishment facilities. During refurbishment operations it was found that numerous TVC frames were experiencing internal corrosion and coating failures, both from salt air and seawater intrusions. Inspectors using borescopes would visually examine the internal cavities of the complicated aluminum alloy welded tubular structure. It was very difficult for inspectors to examine cavity corners and tubing intersections and particularly, to determine the extent of the corrosion and coating anomalies. Physical access to TVC frame internal cavities for corrosion removal and coating repair was virtually impossible, and an improved method using a Liquid (water based) Vapor-phase Corrosion Inhibitor (LVCI) for preventing initiation of new corrosion, and mitigating and/or stopping existing corrosion growth was recommended in lieu of hazardous paint solvents and high VOC / solvent based corrosion inhibitors. In addition, the borescopic inspection method used to detect corrosion, and/or coating anomalies had severe limitations because of part geometry, and an improved non-destructive inspection (NDI) method using Neutron Radiography (N-Ray) was also recommended.

  14. The Effect of Adding Corrosion Inhibitors into an Electroless Nickel Plating Bath for Magnesium Alloys

    NASA Astrophysics Data System (ADS)

    Hu, Rong; Su, Yongyao; Liu, Hongdong; Cheng, Jiang; Yang, Xin; Shao, Zhongcai

    2016-10-01

    In this work, corrosion inhibitors were added into an electroless nickel plating bath to realize nickel-phosphorus (Ni-P) coating deposition on magnesium alloy directly. The performance of five corrosion inhibitors was evaluated by inhibition efficiency. The results showed that only ammonium hydrogen fluoride (NH4HF2) and ammonium molybdate ((NH4)2MoO4) could be used as corrosion inhibitors for magnesium alloy in the bath. Moreover, compounding NH4HF2 and (NH4)2MoO4, the optimal concentrations were both at 1.5 ~ 2%. The deposition process of Ni-P coating was observed by using a scanning electron microscope (SEM). It showed corrosion inhibitors inhibited undesired dissolution of magnesium substrate during the electroless plating process. In addition, SEM observation indicated that the corrosion inhibition reaction and the Ni2+ replacement reaction were competitive at the initial deposition time. Both electrochemical analysis and thermal shock test revealed that the Ni-P coating exhibited excellent corrosion resistance and adhesion properties in protecting the magnesium alloy.

  15. In-situ contact electrical resistance technique for investigating corrosion inhibitor adsorption on copper electrodes

    SciTech Connect

    Moretti, G.; Quartarone, G.; Zingales, A.; Molokanov, V.V.

    1998-02-01

    Traditional electrochemical tests and the contact electrical resistance technique (CER) were used to investigate the effect on corrosion of pure copper (99.999 wt%) of adding benzotriazole (BTA) and 1-hydroxybenzotriazone (1-OH-BTA) to acidic solutions (sulfuric acid [H{sub 2}SO{sub 4}], pH = 1.7, and sodium sulfate [Na{sub 2}SO{sub 4}] until total sulfate [SO{sub 4}{sup 2{minus}}] concentration = 0.1 M). This technique permitted growth of oxide and/or salt films as well as adsorption of the organic inhibitors on the copper surface to be evaluated. Formation of copper oxide ([Cu{sub 2}O]{sub 2})., sulfate (CuSo{sub 4}{center_dot}5H{sub 2}O), thiocyanate (CuSCN), and halogenyde (CuI, CuBr, and CuCl) films on copper electrodes was followed in situ in sulfate solutions at various pH values under low overpotentials. Effects of pH, solution anion content, and/or the amount of BTA or 1-OH-BTA on electrical resistance (R) of the surface films formed on pure copper electrodes were treated. BTA acted as a more efficient corrosion inhibitor than 1-OH-BTA, reaching inhibition percentages (IP) of {approximately}90% compared to those of 1-OH-BTA, which reached a maximum of {approximately}76% in 2 {times} 10{sup {minus}3} M solutions. It was possible to distinguish between maximum R of the surface film, found in solutions containing BTA, associated with the adsorption of neutral inhibitor molecules, and the sharp rise in R attributable to [Cu(BTA)]{sub n} complex formation.

  16. Amine corrosion inhibitor successful in tests at Mobil's Paulsboro refinery

    SciTech Connect

    Not Available

    1986-11-03

    Mobil Oil Corp. has successfully completed a test of an amine unit corrosion inhibition system at its 100,000-b/d refinery in Paulsboro, NJ. The system, the Amine Guard ST system is used to inhibit corrosion of diethanolamine (DEA) sweetening units that treat process streams from the fluid catalytic cracker (FCC), a hydrodesulfurization unit (HDU), and lube oil dewaxing (LDW) units at the refinery. Use of the corrosion-inhibition system has allowed an increase in the DEA concentration to 55 wt %, a reduction of the DEA circulation rate by 40%, and a reduction in regeneration steam of 35%.

  17. Effect of silicate-based corrosion inhibitor from rice husk ash on aluminum alloy in 0.5M HCl

    NASA Astrophysics Data System (ADS)

    Othman, N. K.; Mohamad, N.; Zulkafli, R.; Jalar, A.

    2013-05-01

    Silicate-based corrosion inhibitor prepared by treating silica powder extracted from rice husk ash with concentrated alkaline. The electrochemical behavior of the Al 6061 immersed in 0.5 M hydrochloric acid (HCl) has been studied using the measurements of weight loss, potentiodynamic polarization and optical or scanning electron microscopy (SEM). It was found that, the optimum concentration of silicate-based corrosion inhibitor was prominent at 5 ppm. The small addition of silicate-based corrosion inhibitor was exhibited the decreasing of the weight loss of Al 6061 in acidic medium. SEM micrograph proved that the morphology of untreated Al 6061 with silicate-base corrosion inhibitor contributes more corrosion attack on sample compared to that treated Al 6061. The purpose of this research is to understand the effect of silicate-based corrosion inhibitor concentration yielded from rice husk ash on aluminum alloy.

  18. Analysis of corrosion resistance behavior of inhibitors in concrete using electrochemical techniques

    NASA Astrophysics Data System (ADS)

    Song, Ha-Won; Saraswathy, Velu

    2006-08-01

    Reinforced concrete is one of the most durable and cost effective construction materials. However, in high chloride environments, it can suffer from corrosion due to chloride induced breakdown of the normal passive layer protecting the reinforcing steel bars inside concrete. One means of protecting embedded steel reinforcement from chloride induced corrosion is the addition of corrosion inhibiting admixtures. In the present investigation, various inhibitors such as sodium nitrite, zinc oxide, mono ethanol amine, diethanolamine, and triethanol amine have been used in concrete in different percentages. Their effectiveness was then studied using various electrochemical techniques such as rapid chloride ion penetration test, open circuit potential measurement, electrochemical impedance measurement, potentiodynamic polarization measurement, and gravimetric weight loss measurement. The results thus obtained indicate that the addition of inhibitors enhances the corrosion resistance properties.

  19. Detergent and corrosion inhibitor and motor fuel composition containing same

    SciTech Connect

    Kaufman, B.J.; Herbstman, S.; Levin, M.

    1983-09-13

    As a detergent and corrosion inhibiting fuel additive, the product is claimed resulting from reaction of trimellitic anhydride and a N- C/sub 10/-C/sub 25/-hydrocarbyl-1,3-diaminopropane and a fuel composition containing same.

  20. Alkaloids extract of Retama monosperma (L.) Boiss. seeds used as novel eco-friendly inhibitor for carbon steel corrosion in 1 M HCl solution: Electrochemical and surface studies

    NASA Astrophysics Data System (ADS)

    El Hamdani, Naoual; Fdil, Rabiaa; Tourabi, Mustapha; Jama, Charafeddine; Bentiss, Fouad

    2015-12-01

    Current research efforts now focus on the development of non-toxic, inexpensive and environmentally friendly corrosion inhibitors as alternatives to different organic and non-organic compounds. In this field, alkaloids extract of Retama monosperma (L.) Boiss. seeds (AERS) was tested for the first time as corrosion inhibitor for carbon steel in 1 M HCl medium using electrochemical and surface characterization techniques. The obtained results showed that this plant extract's acts as an efficient corrosion inhibitor for carbon steel in 1 M HCl and an inhibition efficiency of 94.4% was reached with 400 mg/L of AERS at 30 °C. Ac impedance experimental data revealed a frequency distribution of the capacitance, simulated as constant phase element. Impedance results demonstrated that the addition of the AERS in the corrosive solution decreases the charge capacitance and simultaneously increases the function of the charge/discharge of the interface, facilitating the formation of an adsorbed layer over the steel surface. Polarization curves indicated that AERS is a mixed inhibitor. Adsorption of such alkaloid extract on the steel surface obeyed to the Langmuir adsorption isotherm. X-ray photoelectron spectroscopy (XPS) showed that the inhibition of steel corrosion in normal hydrochloric solution by AERS is mainly controlled by a physisorption process and the inhibitive layer is composed of an iron oxide/hydroxide mixture where AERS molecules are incorporated.

  1. Experimental and theoretical study of [N-substituted] p-aminoazobenzene derivatives as corrosion inhibitors for mild steel in sulfuric acid solution

    NASA Astrophysics Data System (ADS)

    Shihab, Mehdi Salih; Al-Doori, Hanan Hussien

    2014-11-01

    [N-substituted] p-aminoazobenzene derivatives (1), (2), (3), (4) and (5) were prepared and investigated as corrosion inhibitors for mild steel in 1 M H2SO4 solution by weight loss measurements. It has been observed that the corrosion rate decreases, inhibition efficiencies increase and surface coverage degree increases with increasing inhibitor concentration. Inhibition efficiencies for prepared compounds were ordered: (1) > (2) > (5) > (4) > (3) with the highest inhibiting efficiency of 63% for 10-3 M. The values of ΔGadso are showing physisorption effect for all prepared compounds. Semiempirical molecular orbital calculations for (1), (2), (3), (4) and (5) could be used as a useful tool to obtain information for explaining the nature of interaction between the metal surface and the organic molecule as a corrosion inhibitor.

  2. Self-assembled organic thin films on electroplated copper for prevention of corrosion

    NASA Astrophysics Data System (ADS)

    Tan, Y. S.; Srinivasan, M. P.; Pehkonen, S. O.; Chooi, Simon Y. M.

    2004-07-01

    Self-assembled organic thin films of dodecanethiol (DT), mercaptobenzothiazole (MBT), benzotriazole (BTA), imidazole (IMD) and benzothiazole (BT) are formed by adsorption on the surface of copper thin film used in ultralarge-scale integrated circuits. The films are characterized by x-ray photoelectron spectroscopy. The inhibition of corrosion of these organic thin films is investigated in aerated 0.5 M H2SO4 solutions by electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The presence of these films reduced corrosion by blocking the copper surface from the oxygen dissolved in the acid medium. The relative inhibition efficiencies of these inhibiting agents in preventing copper oxidation are found to be in the order of DT>MBT>BT>BTA>IMD. The effectiveness of the inhibitors increased with the temperature, concentration of the inhibitors, and duration of immersion in the solution. An adsorption model is proposed on the basis of variation of the impedance according to the inhibitor concentration. The stability and packing of the inhibitors on the surface appear to be the most important factors in determining the inhibitive efficiency of the inhibitors. .

  3. Exopolysaccharides from lactic acid bacteria as corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    Ignatova-Ivanova, Tsveteslava; Ivanov, Radoslav

    2016-03-01

    Bacterial EPSs (exopolysaccharides) are believed to play an important role in the environment by promoting survival strategies such as bacterial attachment to surfaces and nutrient trapping, which facilitate processes of biofilm formation and development. These microbial biofilms have been implicated in corrosion of metals, bacterial attachment to prosthetic devices, fouling of heat exchange surfaces, toxicant immobilization, and fouling of ship hulls. In this paper, data on EPS production and the effect of EPS on corrosion of steel produced by Lactobacillus sp. are presented and discussed. Lactobacillus delbrueckii K27, Lactobacillus delbrueckii B8, Lactobacillus delbrueckii KO43, Lactobacillus delbrueckii K3, Lactobacillus delbrueckii K15 and Lactobacillus delbrueckii K17 was obtained from Collection of Department of General and Applied Microbiology, Sofia University. It was tested for its ability to produce exopolysaccharides when cultivated in a media containing 10% sucrose, 10% lacose and 10% maltose. The study of the corrosive stability of steel samples was conducted on the gravimetrique method. The rate of corrosion, the degree of protection, and coefficient of protection have been calculated. The structure of layer over steel plates was analysed by SEM (scanning electron microscopy) JSM 5510. It could be underlined that 10% sucrose, 10% lactose and 10% maltose in the media stimulated the process of protection of corrosion.

  4. A Theoretical Study of Carbohydrates as Corrosion Inhibitors of Iron

    NASA Astrophysics Data System (ADS)

    Khalil, Salim M.; Ali-Shattle, Elbashir E.; Ali, Nozha M.

    2013-09-01

    The inhibitive effect of fructose, glucose, lactose, maltose, and sucrose against the iron corrosion is investigated using density functional theory at the B3LYP/6-31 G level (d) to search the relation between the molecular structure and corrosion inhibition. The electronic properties such as the energy of the highest occupied molecular orbital (HOMO), the energy of lowest unoccupied orbital (LUMO), the energy gap (LUMO-HOMO), quantum chemical parameters such as hardness, softness, the fraction of the electron transferred, and the electrophilicity index are reported. The inhibition efficiency of the investigated carbohydrates follows the trend: maltose

  5. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

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

  6. Corrosion

    ERIC Educational Resources Information Center

    Slabaugh, W. H.

    1974-01-01

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

  7. Role of orthophosphate as a corrosion inhibitor in chloraminated solutions containing tetravalent lead corrosion product PbO2.

    PubMed

    Ng, Ding-Quan; Strathmann, Timothy J; Lin, Yi-Pin

    2012-10-16

    Addition of orthophosphate has been commonly employed to suppress lead levels in drinking water. Its detailed mechanism and time required for it to become effective, however, have not been fully elucidated. In this study, we investigated the mechanistic role of orthophosphate as a corrosion inhibitor in controlling lead release from tetravalent lead corrosion product PbO(2) in chloraminated solutions, a system representing distribution networks experiencing disinfectant changeover from free chlorine to monochloramine. In all experiments with orthophosphate addition of at least 1 mg/L as P, peaking of soluble Pb(II) concentration within the first 24 h was observed before lead concentrations decreased and stabilized at levels lower than 15 μg/L. The variation of soluble Pb(II) concentration could be attributed to the dynamics between the rate of PbO(2) reductive dissolution, primarily induced by monochloramine decomposition, and that of chloropyromorphite (Pb(5)(PO(4))(3)Cl) precipitation, which did not occur until a critical supersaturation ratio of about 2.36 was reached in the solution. Our findings provide insights to how orthophosphate reduces lead levels under drinking water conditions and highlight the potential risk of short-term elevated lead concentrations. Intensive monitoring following the disinfectant changeover may be required to determine the overall lead exposure when using orthophosphate as a corrosion inhibitor.

  8. Nano-silicate inhibitor derived from rice husk for corrosion mitigation of steel in distilled water

    NASA Astrophysics Data System (ADS)

    Asra, Denni; Othman, Norinsan Kamil; Dasuki, Zulhusni

    2017-05-01

    Nanosilicate extracts from rice husk (Oryza sativa L.) ash (RHA) as a corrosion inhibitor for carbon steel in distilled water has been investigated. The nanosilicates extracted from RHA was obtained through wet chemical extraction and the extracted nanosilicates powder were analyzed using Fourier Transform Infrared Spectroscopy (FTIR) in order to identify the presence of functional groups (SiO2) that contributed to the inhibition process. The particle size of extracted nanosilica is in the range of 5-10 nm and it was confirmed through Transmission electron microscopy (TEM) and Zeta Sizer analysis. The corrosion measurement study on the effect of nanosilicate from RHA on carbon steel samples in distilled water as corrosive media had been conducted by employing weight loss method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), surface analysis, and adsorption isotherm study. It was proven that the maximum inhibition efficiency (IE %) obtained through corrosion measurement were up to 98 % of inhibition. On the other hand, the adsorption of inhibitor on the carbon steel surface was found to follow Temkin isotherm. Based on the result of potentiodynamic polarization, it showed that inhibitors are mixed type. The results of EIS showed that value of charge transfer resistance and the percentage of inhibition efficiency increased with the increasing of nanosilicate concentration. Surface analysis on specimen that was treated with nanosilicate were smoother with fewer corrosion products compared to untreated specimen.

  9. Theoretical study of inhibition efficiencies of some amino acids on corrosion of carbon steel in acidic media: green corrosion inhibitors.

    PubMed

    Dehdab, Maryam; Shahraki, Mehdi; Habibi-Khorassani, Sayyed Mostafa

    2016-01-01

    Inhibition efficiencies of three amino acids [tryptophan (B), tyrosine (c), and serine (A)] have been studied as green corrosion inhibitors on corrosion of carbon steel using density functional theory (DFT) method in gas and aqueous phases. Quantum chemical parameters such as EH OMO (highest occupied molecular orbital energy), E LUMO (lowest unoccupied molecular orbital energy), hardness (η), polarizability ([Formula: see text]), total negative charges on atoms (TNC), molecular volume (MV) and total energy (TE) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Consistent with experimental data, theoretical results showed that the order of inhibition efficiency is tryptophan (B) > tyrosine (C) > serine (A). In order to determine the possible sites of nucleophilic and electrophilic attacks, local reactivity has been evaluated through Fukui indices.

  10. Decyl glucoside as a corrosion inhibitor for magnesium-air battery

    NASA Astrophysics Data System (ADS)

    Deyab, M. A.

    2016-09-01

    In this research, the effects of decyl glucoside (DG) on the corrosion inhibition and battery performance of Mg-air battery have been investigated. Chemical and electrochemical techniques have been used to evaluate the corrosion rate and inhibitor efficiency. Mg surface has been characterized with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR). A significant reduction in the corrosion rate of Mg in battery electrolyte (3.5% NaCl solution) has been observed in the presence of DG surfactant. Maximum inhibition efficiency (>94%) is achieved at critical micelle concentration of DG surfactant (CMC = 2.5 mM). The presence of DG surfactant increases the activation energy of the corrosion reaction. Physisorption mechanism has been suggested for the inhibition action of DG surfactant. The Mg-air battery containing DG surfactant offers higher operating voltage, discharge capacity and anodic utilization than in its absence.

  11. Antibacterial drugs as corrosion inhibitors for bronze surfaces in acidic solutions

    NASA Astrophysics Data System (ADS)

    Rotaru, Ileana; Varvara, Simona; Gaina, Luiza; Muresan, Liana Maria

    2014-12-01

    The present study is aiming to investigate the effect of four antibiotics (amoxicillin, ciprofloxacin, doxycycline and streptomycin,) belonging to different classes of antibacterial drugs on bronze corrosion in a solution simulating an acid rain (pH 4). Due to their ability to form protective films on the metal surface, the tested antibiotics act as corrosion inhibitors for bronze. The antibiotics were tested at various concentrations in order to determine the optimal concentration range for the best corrosion inhibiting effect. In evaluating the inhibition efficiency, polarization curves, electrochemical impedance spectroscopy, SEM and XPS measurements were used. Moreover, a correlation between the inhibition efficiency of some antibacterial drugs and certain molecular parameters was determined by quantum chemical computations. Parameters like energies EHOMO and ELUMO and HOMO-LUMO energy gap were used for correlation with the corrosion data.

  12. Quantitative structure activity relationships of some pyridine derivatives as corrosion inhibitors of steel in acidic medium.

    PubMed

    El Ashry, El Sayed H; El Nemr, Ahmed; Ragab, Safaa

    2012-03-01

    Quantum chemical calculations using the density functional theory (B3LYP/6-31G DFT) and semi-empirical AM1 methods were performed on ten pyridine derivatives used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between molecular structure and their inhibition efficiencies. Quantum chemical parameters such as total negative charge (TNC) on the molecule, energy of highest occupied molecular orbital (E (HOMO)), energy of lowest unoccupied molecular orbital (E (LUMO)) and dipole moment (μ) as well as linear solvation energy terms, molecular volume (Vi) and dipolar-polarization (π) were correlated to corrosion inhibition efficiency of ten pyridine derivatives. A possible correlation between corrosion inhibition efficiencies and structural properties was searched to reduce the number of compounds to be selected for testing from a library of compounds. It was found that theoretical data support the experimental results. The results were used to predict the corrosion inhibition of 24 related pyridine derivatives.

  13. Multipurpose Corrosion Inhibitors for Aerospace Materials in Naval Environments

    DTIC Science & Technology

    1987-06-04

    environment becomes acidic, as is the case at the crack-tip. Molybdates. tungstates , vanadates, bismuthates, antimonates, peroxycarbonates are the compounds...inhibitors, the results of Parrish et al (17) have been used. A one percent solution of sodium chloride at pH 2, suggested as an extreme possible condition...used to study the effect of inhibitors. Among the inhibitors investigated, sodium dichromate and sodium molybdate were found to significantly inhibit

  14. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    SciTech Connect

    Bill W. Bogan; Brigid M. Lamb; Gemma Husmillo; Kristine Lowe; J. Robert Paterek; John J. Kilbane II

    2004-12-01

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Various chemicals that inhibit the growth and/or the metabolism of corrosion-associated microbes such as sulfate reducing bacteria, denitrifying bacteria, and methanogenic bacteria were evaluated to determine their ability to inhibit corrosion in experiments utilizing pure and mixed bacterial cultures, and planktonic cultures as well as mature biofilms. Planktonic cultures are easier to inhibit than mature biofilms but several compounds were shown to be effective in decreasing the amount of metal corrosion. Of the compounds tested hexane extracts of Capsicum pepper plants and molybdate were the most effective inhibitors of sulfate reducing bacteria, bismuth nitrate was the most effective inhibitor of nitrate reducing bacteria, and 4-((pyridine-2-yl)methylamino)benzoic acid (PMBA) was the most effective inhibitor of methanogenic bacteria. All of these compounds were demonstrated to minimize corrosion due to MIC, at least in some circumstances. The results obtained in this project are consistent with the hypothesis that any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion. This approach of controlling MIC by controlling the metabolism of biofilms is more environmentally benign than the current approach involving the use of potent biocides, and warrants further investigation.

  15. Safe corrosion inhibitor for treating cooling water on heat power engineering plants

    NASA Astrophysics Data System (ADS)

    Nikolaeva, L. A.; Khasanova, D. I.; Mukhutdinova, E. R.; Safin, D. Kh.; Sharifullin, I. G.

    2017-08-01

    Heat power engineering (HPE) consumes significant volumes of water. There are, therefore, problems associated with corrosion, biological fouling, salt deposits, and sludge formation on functional surfaces of heat power equipment. One of the effective ways to solve these problems is the use of inhibitory protection. The development of new Russian import-substituting environmentally friendly inhibitors is very relevant. This work describes experimental results on the OPC-800 inhibitor (TU 2415-092-00206 457-2013), which was produced at Karpov Chemical Plant and designed to remove mineral deposits, scale, and biological fouling from the surfaces of water-rotation node systems on HPE objects. This reagent is successfully used as an effective corrosion inhibitor in the water recycling systems of Tatarstan petrochemical enterprises. To save fresh make-up water, the circulating system is operated in a no-blow mode, which is characterized by high evaporation and salt content coefficients. It was experimentally found that corrosion rate upon treatment of recycled water with the OPC-800 inhibitor is 0.08-0.10 mm/year. HPE mainly uses inhibitors based on oxyethylidene diphosphonic (OEDPA) and nitrilotrimethylphosphonic (NTMPA) acids. The comparative characteristic of inhibition efficiency for OPC-800 and OEDF-Zn-U2 is given. The results obtained indicate that OPC-800 can be used as an inhibitor for treatment of cooling water in HPE plants. In this case, it is necessary to take into account the features of water rotation of a thermal power plant.

  16. Corrosion inhibition by inorganic cationic inhibitors on the high strength alumunium alloy, 2024-T3

    NASA Astrophysics Data System (ADS)

    Chilukuri, Anusha

    The toxicity and carcinogenic nature of chromates has led to the investigation of environmentally friendly compounds that offer good corrosion resistance to AA 2024-T3. Among the candidate inhibitors are rare earth metal cationic (REM) and zinc compounds, which have received much of attention over the past two decades. A comparative study on the corrosion inhibition caused by rare earth metal cations, Ce3+, Pr3+, La3+ and Zn2+ cations on the alloy was done. Cathodic polarization showed that these inhibitor ions suppress the oxygen reduction reaction (ORR) to varying extents with Zn2+ providing the best inhibition. Pr3+ exhibited windows of concentration (100-300 ppm) in which the corrosion rate is minimum; similar to the Ce3+ cation. Scanning Electron Microscopy (SEM) studies showed that the mechanism of inhibition of the Pr3+ ion is also similar to that of the Ce3+ ion. Potentiodynamic polarization experiments after 30 min immersion time showed greatest suppression of oxygen reduction reaction in neutral chloride solutions (pH 7), which reached a maximum at a Zn2+ ion concentration of 5 mM. Anodic polarization experiments after 30 min immersion time, showed no anodic inhibition by the inhibitor in any concentration (0.1 mM - 10 mM) and at any pH. However, anodic polarization of samples immersed after longer immersion times (upto 4 days) in mildly acidic Zn2+ (pH 4) solutions showed significant reduction in anodic kinetics indicating that zinc also acts as a “slow anodic inhibitor”. In contrast to the polarization experiments, coupons exposed to inhibited acidic solutions at pH 4 showed complete suppression of dissolution of Al2CuMg particles compared to zinc-free solutions in the SEM studies. Samples exposed in pH 4 Zn2+-bearing solution exhibited highest polarization resistance which was also observed to increase with time. In deaerated solutions, the inhibition by Zn2+ at pH 4 is not observed as strongly. The ability to make the interfacial electrolyte

  17. Assessment of high performance concrete containing fly ash and calcium nitrite based corrosion inhibitor as a mean to prevent the corrosion of reinforcing steel

    NASA Astrophysics Data System (ADS)

    Montes-García, P.; Jiménez-Quero, V.; López-Calvo, H.

    2015-01-01

    This research analyses the effectiveness of the water-to-cement ratio (w/c), fly ash and a calcium nitrite based corrosion inhibitor to prevent the corrosion of reinforcing steel embedded in high performance concrete. The interactive effect between the inhibitor and fly ash was evaluated because the occurrence of a negative effect when both ingredients are added together in a concrete mixture has been reported. All the concrete mixtures studied in this investigation had 8.2% of silica fume. Twenty seven prismatic concrete specimens were fabricated with dimensions of 55 × 230 × 300 mm each containing two steel rods embedded for the purpose of corrosion monitoring. The specimens were exposed to a simulated marine environment with two daily cycles of wetting and drying for one year. To evaluate the deterioration of the specimens corrosion potentials and linear polarization resistance tests were carried out. The results indicate that the use of a low w/c, the addition of fly ash and the addition of the corrosion inhibitor contributed to the reduction of the corrosion of steel in the concrete specimens. The results further suggest that the combination of fly ash and corrosion inhibitor does not promote the deterioration of the concrete matrix.

  18. Application of carbohydrate polymers as corrosion inhibitors for metal substrates in different media: A review.

    PubMed

    Umoren, Saviour A; Eduok, Ubong M

    2016-04-20

    Naturally occurring polysaccharides are biopolymers existing as products of biochemical processes in living systems. A wide variety of them have been employed for various material applications; as binders, coatings, drug delivery, corrosion inhibitors etc. This review describes the application of some green and benign carbohydrate biopolymers and their derivatives for inhibition of metal corrosion. Their modes and mechanisms of protection have also been described as directly related to their macromolecular weights, chemical composition and their unique molecular and electronic structures. For instance, cellulose and chitosan possess free amine and hydroxyl groups capable of metal ion chelation and their lone pairs of electrons are readily utilized for coordinate bonding at the metal/solution interface. Some of the carbohydrate polymers reviewed in this work are either pure or modified forms; their grafted systems and nanoparticle composites with multitude potentials for metal protection applications have also been highlighted. Few inhibitors grafted to introduce more compact structures with polar groups capable of increasing the total energy of the surface have also been mentioned. Exudate gums, carboxymethyl and hydroxyethyl cellulose, starch, pectin and pectates, substituted/modified chitosans, carrageenan, dextrin/cyclodextrins and alginates have been elaborately reviewed, including the effects of halide additives on their anticorrosion performances. Aspects of computational/theoretical approach to corrosion monitoring have been recommended for future studies. This non-experimental approach to corrosion could foster a better understanding of the corrosion inhibition processes by correlating actual inhibition mechanisms with molecular structures of these carbohydrate polymers.

  19. Ab initio modeling of the bonding of benzotriazole corrosion inhibitor to reduced and oxidized copper surfaces.

    PubMed

    Kokalj, Anton

    2015-01-01

    The bonding of benzotriazole-an outstanding corrosion inhibitor for copper-on reduced and oxidized copper surfaces is discussed on the basis of density functional theory (DFT) calculations. Calculations reveal that benzotriazole is able to bond with oxide-free and oxidized copper surfaces and on both of them it bonds significantly stronger to coordinatively unsaturated Cu sites. This suggests that benzotriazole is able to passivate the reactive under-coordinated surface sites that are plausible microscopic sites for corrosion attack. Benzotriazole can adsorb in a variety of different forms, yet it forms a strong molecule-surface bond only in deprotonated form. The bonding is even stronger when the deprotonated form is incorporated into organometallic adcomplexes. This is consistent with existing experimental evidence that benzotriazole inhibits corrosion by forming protective organometallic complexes. It is further shown that adsorption of benzotriazole considerably reduces the metal work function, which is a consequence of a large permanent molecular dipole and a properly oriented adsorption structure. It is argued that such a pronounced effect on the work function might be relevant for corrosion inhibition, because it should diminish the anodic corrosion reaction, which is consistent with existing experimental evidence that benzotriazole, although a mixed type inhibitor, predominantly affects the anodic reaction.

  20. Electrochemical investigation of thiourea as corrosion inhibitor for copper in acidic solution

    NASA Astrophysics Data System (ADS)

    Wu, Jintian; Wang, Lingling; Liu, Peidong; Liu, Yuanjie; Chen, Bei; Tao, Zhihua; He, Wei

    2017-04-01

    The thiourea as a copper corrosion inhibitor in the base electrolyte (containing 0.54M H2SO4 and 0.88M CuSO4) was investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The research results suggest that the inhibition efficiency depends on the concentration of the thiourea. The slopes of the cathodic and anodic Tafel lines are approximately constant and independent on the inhibitor concentration. Potentiodynamic polarization curves showed that thiourea acts as the mixed-up inhibitor. The results obtained from EIS measurements are in good agreement with that obtained from potentiodynamic polarization.

  1. A pharmaceutical product as corrosion inhibitor for carbon steel in acidic environments.

    PubMed

    Samide, Adriana

    2013-01-01

    A pharmaceutical product, Trimethoprim (TMP), IUPAC name: 5-(3,4,5-trimethoxybenzyl)pyrimidine-2,4-diamine was investigated, as inhibitor to prevent carbon steel corrosion in acidic environments. The study was performed using weight loss and electrochemical measurements, in temperatures ranging between 25-55°C. The surface morphology before and after corrosion of carbon steel in 1.0 M HCl solution in the presence and absence of TMP was evaluated using scanning electron microscopy (SEM). The inhibition efficiency (IE) increased with the increasing of the inhibitor concentration, reaching a maximum value of 92% at 25°C and 0.9 mM TMP, and decreased with increasing temperature. The inhibition of carbon steel corrosion by TMP can be attributed to the adsorption ability of inhibitor molecules onto the reactive sites of the metal surface. The adsorption is spontaneous and it is best described by the Langmuir isotherm. The apparent activation energy (E(a)) for the corrosion process in the absence and presence of TMP was evaluated from Arrhenius equation, to elucidate its inhibitive properties.

  2. Fluorinated schiff base compound as corrosion inhibitor for steel

    SciTech Connect

    Mehta, N.K.; Agarwala, V.S.; Perez, A.; Rajan, K.S.

    1995-12-01

    A study to evaluate wear and corrosion inhibition, and the mode of molecular bonding of a fluorinated schiff base compound (imine compounds), a condensation reaction product of 4-fluorobenzaldehyde and 4,4{prime}-benzidine, onto AISI 1010 steel surface was undertaken to develop a new lubricant additive for creases, Physical vapor adsorption and chemisorption techniques were used for the deposition of schiff base on the metal surface. The schiff base was found to adhere best with the physical adsorption technique. It involved heating of freshly cleaned specimens suspended over schiff base in an all-glass covered container placed in a vacuum oven maintained at 420 F for approximately 70 hours. Potentiodynamic polarization measurements, made in a 0.1 % sodium chloride solution, showed a drastic shift of the anodic polarization curves to lower current densities for the steel specimens coated with schiff base. The calculated corrosion inhibition efficiency was >90 percent for the compound under both deposition techniques. The four-ball wear test showed a 34--40% reduction in scar size when used as an additive to a MIL-G-24139 grease.

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

    SciTech Connect

    Wiersma, B

    2008-01-04

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

  4. Performance evaluation of pectin as ecofriendly corrosion inhibitor for X60 pipeline steel in acid medium: experimental and theoretical approaches.

    PubMed

    Umoren, Saviour A; Obot, Ime B; Madhankumar, A; Gasem, Zuhair M

    2015-06-25

    The corrosion inhibition effect of pectin (a biopolymer) for X60 pipeline steel in HCl medium was investigated using weight loss, electrochemical, water contact angle measurements, and scanning electron microscopy techniques. The results obtained show that pectin acts as a good corrosion inhibitor for X60 steel. Inhibition efficiency increased with increase in pectin concentration and temperature. Potentiodynamic polarization results reveal that pectin could be classified as a mixed-type corrosion inhibitor with predominant control of the cathodic reaction. The effective corrosion inhibition potential of pectin could be related to the adsorption of pectin molecules at the metal/solution interface which is found to accord with the Langmuir adsorption isotherm model and a protective film formation. Quantum chemical calculations provided insights into the active sites and reactivity parameters governing pectin activity as a good corrosion inhibitor for X60 steel.

  5. Chitosan as a green inhibitor for copper corrosion in acidic medium.

    PubMed

    El-Haddad, Mahmoud N

    2013-04-01

    The behavior of copper in 0.5 M HCl acid containing different concentrations of chitosan has been studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) measurements. Potentiodynamic polarization measurements show that the chitosan acts essentially as a mixed-type inhibitor. EFM can be used as a rapid and non destructive technique for corrosion rate measurements without prior knowledge of Tafel constants. The results of EIS indicate that the value of CPEs tends to decrease and both charge transfer resistance and inhibition efficiency tend to increase by increasing the inhibitor concentration. The investigated inhibitor has shown good inhibition efficiency in 0.5 M HCl. The adsorption of inhibitor on the copper surface obeys Langmuir's isotherm. Metal surface characterization was performed using scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR). Also, the relationship between quantum chemical calculations and experimental inhibition efficiency of the inhibitor was discussed.

  6. The microwave assisted synthesis of 1-alkyl-3-methylimidazolium bromide as potential corrosion inhibitor toward carbon steel in 1 M HCl solution saturated with carbon dioxide

    SciTech Connect

    Pasasa, Norman Vincent A. Bundjali, Bunbun; Wahyuningrum, Deana

    2015-09-30

    Injection of corrosion inhibitor into the fluid current of oil and gas pipelines is an effective way to mitigate corrosion rate on the inner-surface parts of pipelines, especially carbon steel pipelines. In this research, two alkylimidazolium ionic liquids, 1-decyl-3-methylimidazolium bromide (IL1) and 1-dodecyl-3-methylimidazolium bromide (IL2) have been synthesized and studied as a potential corrosion inhibitor towards carbon steel in 1 M HCl solution saturated with carbon dioxide. IL1 and IL2 were synthesized using microwave assisted organic synthesis (MAOS) method. Mass Spectrometry analysis of IL1 and IL2 showed molecular mass [M-H+] peak at 223.2166 and 251.2484, respectively. The FTIR,{sup 1}H-NMR and {sup 13}C-NMR spectra confirmed that IL1 and IL2 were successfully synthesized. Corrosion inhibition activity of IL1 and IL2 were determined using weight loss method. The results showed that IL1 and IL2 have the potential as good corrosion inhibitors with corrosion inhibition efficiency of IL1 and IL2 are 96.00% at 100 ppm (343 K) and 95.60% at 50 ppm (343 K), respectively. The increase in the concentration of IL1 and IL2 tends to improve their corrosion inhibition activities. Analysis of the data obtained from the weight loss method shows that the adsorption of IL1 and IL2 on carbon steel is classified into chemisorption which obeys Langmuir’s adsorption isotherm.

  7. Investigation of some green compounds as corrosion and scale inhibitors for cooling systems

    SciTech Connect

    Quraishi, M.A.; Farooqi, I.H.; Saini, P.A. )

    1999-05-01

    The performance of an open-recirculating cooling system, an important component in most industries, is affected by corrosion and scale formation. Numerous additives have been used in the past for the control of corrosion and scale formation. Effects of the naturally occurring compounds azadirachta indica (leaves), punica granatum (shell), and momordica charantia (fruits), on corrosion of mild steel in 3% sodium chloride (NaCl) were assessed using weight loss, electrochemical polarization, and impedance techniques. Extracts of the compounds exhibited excellent inhibition efficiencies comparable to that of hydroxyethylidine diphosphonic acid (HEDP), the most preferred cooling water inhibitor. The compounds were found effective under static and flowing conditions. Extracts were quite effective in retarding formation of scales, and the maximum antiscaling efficiency was exhibited by the extract of azadirachta indica (98%). The blowdown of the cooling system possessed color and chemical oxygen demand (COD). Concentrations of these parameters were reduced by an adsorption process using activated carbon as an adsorbent.

  8. Polysaccharide from Plantago as a green corrosion inhibitor for carbon steel in 1M HCl solution.

    PubMed

    Mobin, Mohammad; Rizvi, Marziya

    2017-03-15

    Polysaccharide from Plantago ovata was investigated for its inhibition characteristics for carbon steel corrosion in 1M HCl. The mucilage of the Plantago is comprised of a highly branched polysaccharide, arabinosyl (galaturonic acid) rhamnosylxylan (AX), which is mainly responsible for the corrosion inhibition of the carbon steel. The techniques that were used to assess the inhibition and adsorption properties of the AX in the acid solution are gravimetric method, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-vis spectroscopy and FTIR. Thermodynamic and activation parameters revealed that the spontaneous adsorption of AX on carbon steel was mixed type and predominantly chemical in nature. Quantum chemical analysis supports the proposed mechanism of inhibition. AX from Plantago could serve as a green corrosion inhibitor for the carbon steel in hydrochloric medium with good inhibition efficiency but low risk of environmental pollution.

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

    SciTech Connect

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

    2007-08-28

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

  10. Substituted benzotriazoles as inhibitors of copper corrosion in borate buffer solutions

    NASA Astrophysics Data System (ADS)

    Agafonkina, M. O.; Andreeva, N. P.; Kuznetsov, Yu. I.; Timashev, S. F.

    2017-08-01

    The adsorption of substituted 1,2,3-benzotriazoles (R-BTAs) onto copper is measured via ellipsometry in a pure borate buffer (pH 7.4) and satisfactorily described by Temkin's isotherm. The adsorption free energy (-Δ G a 0 ) values of these azoles are determined. The (-Δ G a 0 ) values are found to rise as their hydrophobicity, characterized by the logarithm of the partition coefficient of a substituted BTA in a model octanol-water system (log P), grows. The minimum concentration sufficient for the spontaneous passivation of copper ( C min) and a shift in the potential of local copper depassivation with chlorides ( E pt) after an azole is added to the solution (i.e., Δ E = E pt in - E pt backgr characterizing the ability of its adsorption to stabilize passivation) are determined in the same solution containing a corrosion additive (0.01M NaCl) for each azole under study. Both criteria of the passivating properties of azoles (log C min and Δ E) are shown to correlate linearly with log P, testifying to the role played by surface activity of this family of organic inhibitors in protecting copper in an aqueous solution.

  11. SERS and DFT study of copper surfaces coated with corrosion inhibitor

    PubMed Central

    Muniz-Miranda, Francesco; Caporali, Stefano

    2014-01-01

    Summary Azole derivatives are common inhibitors of copper corrosion due to the chemical adsorption occurring on the metal surface that gives rise to a protective film. In particular, 1,2,4-triazole performs comparable to benzotriazole, which is much more widely used, but is by no means an environmentally friendly agent. In this study, we have analyzed the adsorption of 1,2,4-triazole on copper by taking advantage of the surface-enhanced Raman scattering (SERS) effect, which highlights the vibrational features of organic ligand monolayers adhering to rough surfaces of some metals such as gold, silver and copper. To ensure the necessary SERS activation, a roughening procedure was implemented on the copper substrates, resulting in nanoscale surface structures, as evidenced by microscopic investigation. To obtain sufficient information on the molecule–metal interaction and the formation of an anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT) approach. PMID:25671144

  12. Some nonionic surfactants as inhibitors of the corrosion of iron in acid chloride solutions

    SciTech Connect

    Elachouri, M.; Hajji, M.S.; Salem, M.; Kertit, S.; Aride, J.; Coudert, R.; Essassi, E.

    1996-02-01

    The inhibition effect of the surfactants 1,2-hexanediol (HD), 1,2,3-octanetriol (OT); 1,2,3-nonanetriol (NT); and 3,7-dimethyl-1,2,3,6,7-octanepentol (DOP) on the corrosion of iron in 1 M hydrochloric acid (HCl) was studied. Results obtained from gravimetric methods showed inhibition efficiencies increased with increasing surfactant concentrations and attained a maximum round their critical micellar concentration (cmc). A comparative study of corrosion inhibition of surfactants indicted DOP was the best inhibitor. Polarization measurements showed DOP was a cathodic type-inhibitor and acted on the cathodic reaction without modifying the mechanism of the hydrogen evolution reaction. DOP appeared to function through a general adsorption mode following the Langmuir adsorption isotherm. The effect of temperature on the corrosion behavior of iron in both 1 M HCl and 1 M HCl with addition of various concentrations of DOP was studied in the temperature range from 18 C to 48 C. The associated activation corrosion and free adsorption energies were determined.

  13. Electrochemical Study on Newly Synthesized Chlorocurcumin as an Inhibitor for Mild Steel Corrosion in Hydrochloric Acid

    PubMed Central

    Al-Amiery, Ahmed A.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Musa, Ahmed Y.; Li, Cheong Jiun

    2013-01-01

    A new curcumin derivative, i.e., (1E,4Z,6E)-5-chloro-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one (chlorocurcumin), was prepared starting with the natural compound curcumin. The newly synthesized compound was characterized by elemental analysis and spectral studies (IR, 1H-NMR and 13C-NMR). The corrosion inhibition of mild steel in 1 M HCl by chlorocurcumin has been studied using potentiodynamic polarization (PDP) measurements and electrochemical impedance spectroscopy (EIS). The inhibition efficiency increases with the concentration of the inhibitor but decreases with increases in temperature. The potentiodynamic polarization reveals that chlorocurcumin is a mixed-type inhibitor. The kinetic parameters for mild steel corrosion were determined and discussed. PMID:28788402

  14. Electrochemical Studies on Silicate and Bicarbonate Ions for Corrosion Inhibitors

    NASA Astrophysics Data System (ADS)

    Mohorich, Michael E.; Lamb, Joshua; Chandra, Dhanesh; Daemen, Jaak; Rebak, Raul B.

    2010-10-01

    Several types of carbon and high-strength low-alloy (HSLA) steels are being considered for use in the underground reinforcement of the Yucca Mountain Nuclear Waste Repository. In this study, potentiodynamic polarization under reducing conditions was used to determine the corrosion rates (CRs) and passivity behavior of AISI 4340 steel using different combinations of sodium silicate (Na2SiO3) and sodium bicarbonate (NaHCO3), in both pure water (PW) and simulated seawater (SW, 3.5 pct NaCl). These experiments were carried out to examine the potential inhibiting properties of the silicate or bicarbonate ions on the surface of the steel. The addition of sodium silicate to solution reduced the observed CR at room temperature to 19 μm/y at 0.005 M concentration and 7 μm/y at 0.025 M concentration in PW. The addition of sodium bicarbonate increased the CR from 84 μm/y (C = 0.1 M) to 455 μm/y (C = 1 M). These same behaviors were also observed at higher temperatures.

  15. The application of ion-exchanged clay as corrosion inhibiting pigments in organic coatings

    NASA Astrophysics Data System (ADS)

    Chrisanti, Santi

    High strength aluminum alloys are used in aerospace industry and are normally coated to prevent corrosion. The corrosion protection of the coatings is mainly provided by pigmented-primer layer. Strontium chromate pigments are widely used, but they are toxic and carcinogenic. The objective of the current study is to develop and characterize the ion exchange compounds bentonite and hydrotalcite as corrosion inhibiting pigments. These compounds were synthesized with different cations and anions, and were used either alone or in mixtures as particulate additive in organic coatings. In coating applications as well as bulk solution, the inhibitor release mechanism is based on ion exchange. To evaluate corrosion inhibition, pigments extract solutions were used in potentiodynamic polarization as well as electrochemical impedance spectroscopy (EIS) experiments on bare aluminum alloy 2024-T3. Cathodic polarization showed that zinc- and cerium-containing filtrate solutions modestly inhibited cathodic current density. These solutions also decreased the extent of pitting damage formed on the surface, as compared to uninhibited 0.5 M NaCl solution. Pigments were also added as primer additives, and painted on AA2024-T3. The coated panels were then subjected to salt spray exposure testing. The possibility of sensing inhibitor exhaustion by means of X-ray diffraction interrogation of the pigment in a coating is demonstrated and discussed on cerium bentonite-pigmented coatings. Although cerium bentonite-pigmented coatings did not show behavior indicative of self-healing, the combination of bentonite and hydrotalcite that released Ce3+, Zn 2+, and PO43- showed potent scribe protection even after 3000 h exposure in salt spray. Promising self-healing was also demonstrated by pigments that consisted of decavanadate-hydrotalcite and zinc pyrovanadate, as indicated by a shiny scribed area after 1000h exposure in salt spray. When these pigments are used, blistering is minimized.

  16. Caprylate Salts Based on Amines as Volatile Corrosion Inhibitors for Metallic Zinc: Theoretical and Experimental Studies

    PubMed Central

    Valente, Marco A. G.; Teixeira, Deiver A.; Azevedo, David L.; Feliciano, Gustavo T.; Benedetti, Assis V.; Fugivara, Cecílio S.

    2017-01-01

    The interaction of volatile corrosion inhibitors (VCI), caprylate salt derivatives from amines, with zinc metallic surfaces is assessed by density functional theory (DFT) computer simulations, electrochemical impedance (EIS) measurements and humid chamber tests. The results obtained by the different methods were compared, and linear correlations were obtained between theoretical and experimental data. The correlations between experimental and theoretical results showed that the molecular size is the determining factor in the inhibition efficiency. The models used and experimental results indicated that dicyclohexylamine caprylate is the most efficient inhibitor. PMID:28620602

  17. Comparison of three corrosion inhibitors in simulated partial lead service line replacements.

    PubMed

    Kogo, Aki; Payne, Sarah Jane; Andrews, Robert C

    2017-05-05

    Partial lead service line replacements (PLSLR) were simulated using five recirculating pipe loops treated with either zinc orthophosphate (1mg/L as P), orthophosphate (1mg/L as P) or sodium silicate (10mg/L). Two pipe loops served as ⿿inhibitor-free⿿ (Pb-Cu) and ⿿galvanic free⿿ (Pb-PVC) controls. Changes in water quality (CSMR [0.2 or 1], conductivity [⿿330mS/cm or ⿿560mS/cm], chlorine [1.4mg/L]) were not observed to provide a significant impact on lead or copper release, although galvanic corrosion was shown to be a driving factor. Generally, both orthophosphate and zinc orthophosphate provided better corrosion control for both total and dissolved lead (30min, 6h, 65h) and copper (30min, 6h), when compared to either the inhibitor-free control or the sodium silicate treated system. This work highlights the importance of understanding the complex interplay of corrosion inhibitors on particulate and dissolved species when considering both lead and copper.

  18. Study of caffeine as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    NASA Astrophysics Data System (ADS)

    Solehudin, Agus; Berman, Ega Taqwali; Nurdin, Isdiriayani

    2015-09-01

    The corrosion behaviour of steel surface in the absence and presence of caffeine in 3.5% NaCl solution containing dissolved H2S gas is studied using electrochemical impedance spectroscopy (EIS). The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H2S at different caffeine concentrations showed that corrosion rate of carbon steel decreases with increasing of caffeine concentrations from 0 to 0,1 mmol/l. Whereas, the corrosion rate increase with increasing of caffeine concentrations from 1 to 10 mmol/l. It is clear that no inhibition efficiency increases with increasing inhibitor concentration. The optimum value of inhibition efficiency was 90% at a caffeine concentration of 0.1 mmol/l. This suggests that caffeine's performance as a corrosion inhibitor is more effective at a concentration of 0.1 mmol/l.

  19. Novel Galvanic Corrosion Inhibitors: Synthesis, Characterization, Fabrication and Testing

    DTIC Science & Technology

    2007-09-30

    Aluminosilicate Clinoptilolite for Ammonia Removal in Shoreline Aquaculture System," 3 2 nd Annual National Organization of Black Chemists and Chemical...Material Symposium, Cape Town, South Africa, 2004. 31. "Nanoporous Aluminosilicate Clinoptilolite for Ammonia Removal in Shoreline Aquaculture System

  20. Effect of multi-functional inhibitors on the electrochemistry within a corrosion crack

    SciTech Connect

    Omura, H.

    1984-01-01

    The electrochemical and mass transport mechanisms in stress corrosion cracking, which depend on the rate of metal dissolution and production of hydrogen, have been used to establish analytically the electrode potential distribution within the crack. When crack growth occurs by enhanced anodic dissolution of the plastically strained tip, the electrode potential at the crack tip always is more active than at the crack mouth because of the electric potential gradient that exists in the electrolyte within the crack. This also gives rise to additional or alternative electrochemical reactions such as hydrogen evolution and anodic dissolution at the crack tip. Furthermore, because of the potential difference from the crack mouth, the electrochemical driving force becomes more favorable for the development of corrosion inside the crack. The analysis predicts the distribution of electrode potential within a crack, and theoretical results have been compared with experimental measurements recorded from a model electrode system. Under free corrosion, a small potential difference may cause a concentration change of Cl/sup -/ ion and increase the chloride attack. In order to reduce the chloride and hydrogen attack, multifunctional inhibitors, such as borax-nitrite with small amounts of surfactant such as MBT or amino-methyl-propanol, are excellent inhibitors. The surfactant interferes in the dissolution reaction and blocks active chloride ion and hydrogen ion by interacting synergistically with the passive film produced by the borax-nitrite, which results in development of a stronger and thicker protective film.

  1. [Effect of corrosion inhibitor on the producing of exopolymer complex by sulphate-reducing bacteria].

    PubMed

    Purish, L M; Asaulenko, L H; Kozlova, I P

    2007-01-01

    It is established that the specific productivity of exopolymer complex (EPM) synthesized by the cells of sulphate-reducing bacteria in a biofilm was 1.5 times higher than in plankton. A sharp increase of the specific productivity of EPM in the biofilm is observed when corrosion inhibitor is introduced in the environment. The inhibitor concentration being 1.0 g/l, the biofilm cells produced almost 18 times more of EPM than the bacteria cells in plankton. It is shown that the film exopolymers include glucose, galactose, mannose, xylose, ribose and three nondetermined sugars, while plankton cells also include rhamnose. Rhamnose appeared in the biofilm EPM composition and rhamnose, arabinose and fucose appeared in EPM of plankton cells as affected by the inhibitor. A necessity of investigating the biofilm formation for developing the methods of anticorrosive protection is discussed.

  2. New and Green Multi-component Scaling and Corrosion Inhibitor for the Cooling Water of Central Air Conditioners

    NASA Astrophysics Data System (ADS)

    Li, Maodong; Dai, Chenlin; Yang, Bo; Qiao, Yue; Zhu, Zhiping

    2017-02-01

    A green multi-component inhibitor was developed in this study to obtain suitable scale and corrosion inhibitor for the cooling water treatment of central air conditioners. The inhibitor formulation consisted of hydrolyzed polymaleic anhydride/Tween-80/sodium N-lauroyl sarcosinate/tolyltriazole (named 4-HTSA). Weight loss test and electrochemical method were used to investigate the corrosion inhibition performance of 4-HTSA on A3 carbon steel and T2 red copper in synthetic cooling water, and the scale inhibition performance of 4-HTSA was studied by the calcium carbonate precipitation method. The influence of parameters, such as pH, temperature, scaling and corrosive ion, on 4-HTSA was researched. Scanning electron microscopy (SEM) and x-ray diffraction were used for examination of the scale, and corrosion coupons were analyzed by SEM/energy-dispersive x-ray spectroscopy. Results showed that 4-HTSA had excellent scale and corrosion inhibition performance and wide tolerance to pH, temperature and the concentration of scaling and corrosive ion. Polarization curves indicated that 4-HTSA was anodic inhibitor.

  3. New and Green Multi-component Scaling and Corrosion Inhibitor for the Cooling Water of Central Air Conditioners

    NASA Astrophysics Data System (ADS)

    Li, Maodong; Dai, Chenlin; Yang, Bo; Qiao, Yue; Zhu, Zhiping

    2016-12-01

    A green multi-component inhibitor was developed in this study to obtain suitable scale and corrosion inhibitor for the cooling water treatment of central air conditioners. The inhibitor formulation consisted of hydrolyzed polymaleic anhydride/Tween-80/sodium N-lauroyl sarcosinate/tolyltriazole (named 4-HTSA). Weight loss test and electrochemical method were used to investigate the corrosion inhibition performance of 4-HTSA on A3 carbon steel and T2 red copper in synthetic cooling water, and the scale inhibition performance of 4-HTSA was studied by the calcium carbonate precipitation method. The influence of parameters, such as pH, temperature, scaling and corrosive ion, on 4-HTSA was researched. Scanning electron microscopy (SEM) and x-ray diffraction were used for examination of the scale, and corrosion coupons were analyzed by SEM/energy-dispersive x-ray spectroscopy. Results showed that 4-HTSA had excellent scale and corrosion inhibition performance and wide tolerance to pH, temperature and the concentration of scaling and corrosive ion. Polarization curves indicated that 4-HTSA was anodic inhibitor.

  4. Indole Alkaloids of Alstonia angustifolia var. latifolia as Green Inhibitor for Mild Steel Corrosion in 1 M HCl Media

    NASA Astrophysics Data System (ADS)

    Raja, Pandian Bothi; Qureshi, Ahmad Kaleem; Rahim, Afidah Abdul; Awang, Khalijah; Mukhtar, Mat Ropi; Osman, Hasnah

    2013-04-01

    The inhibition effect of mild steel (MS) corrosion in 1 M HCl was studied by the addition of indole alkaloids (crude) isolated from Alstonia angustifolia var. latifolia ( A. latifolia) leaves at 303 K. Potentiodynamic polarization, impedance spectroscopy, scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) analyses were used for this study. Results show that the isolated alkaloid extract of A. latifolia is a good inhibitor and exhibited maximum inhibition efficiency (above 80%) at concentrations between 3 and 5 mg/L. Polarization measurements indicated that the inhibitor does not alter the mechanism of either anodic or cathodic reactions and acted as mixed-type inhibitor. The inhibition efficiencies of both electrochemical techniques are found to be in good agreement and adsorption of inhibitor follows Langmuir isotherm. Adsorption of inhibitor over metal surface was well supported by the SEM studies, while FTIR studies evidenced the presence of indole alkaloids as green inhibitor that reduces the rate of corrosion.

  5. Kinetics of Corrosion Inhibition of Aluminum in Acidic Media by Water-Soluble Natural Polymeric Pectates as Anionic Polyelectrolyte Inhibitors

    PubMed Central

    Hassan, Refat M.; Zaafarany, Ishaq A.

    2013-01-01

    Corrosion inhibition of aluminum (Al) in hydrochloric acid by anionic polyeletrolyte pectates (PEC) as a water-soluble natural polymer polysaccharide has been studied using both gasometric and weight loss techniques. The results drawn from these two techniques are comparable and exhibit negligible differences. The inhibition efficiency was found to increase with increasing inhibitor concentration and decrease with increasing temperature. The inhibition action of PEC on Al metal surface was found to obey the Freundlich isotherm. Factors such as the concentration and geometrical structure of the inhibitor, concentration of the corrosive medium, and temperature affecting the corrosion rates were examined. The kinetic parameters were evaluated and a suitable corrosion mechanism consistent with the kinetic results is discussed in the paper. PMID:28809282

  6. DFT study of the interactions between thiophene-based corrosion inhibitors and an Fe4 cluster.

    PubMed

    Dao, Duy Quang; Hieu, Truong Dinh; Le Minh Pham, Thong; Tuan, Dinh; Nam, Pham Cam; Obot, Ime Bassey

    2017-08-11

    Understanding the physicochemical properties of corrosion inhibitors and their chemical interactions with metal surfaces is crucial to the design of improved (i.e., more efficient) corrosion inhibitors. In this work, the physicochemical properties of six thiophene-based corrosion inhibitors (2-acetylthiophene (AT), 2-formylthiophene (FT), thiophene (Th), 2-methyl-3-thiophenthiol (MTT), 2-pentylthiophene (PT), and 2-thenylthiol (TT)) were systematically studied by performing ab initio calculations at the MP2(full)/6-31G(2df,p) level of theory. Adsorption of the inhibitors on an iron surface was also modeled by investigating the interactions of these molecules with a tetrahedral Fe4 cluster using the B3LYP method and the 6-311G(d,p) basis set or the LanL2DZ basis set. The calculated results indicate that the nature of the substituent group present has a significant impact on the geometric and electronic structures of the thiophene-based molecules. The presence of an electron-donating group causes the electron density in the thiophene ring to increase, while the presence of an electron-withdrawing group has the opposite effect. Accordingly, the examined molecules were ranked in order of corrosion inhibition efficiency as follows: FT ≈ AT < Th < PT < TT < MTT. The calculated binding energies demonstrated that the π-1Fe and π-3Fe interaction configurations dominated over the S-1Fe configuration for all the compounds. Natural bond orbital analysis revealed that all of the thiophene-based compounds donate electrons from the π and σ orbitals of high-electron-density regions such as C2-S1-C5 and C3-C4 or from two lone pairs on S1 to the Fe4 cluster. Although electron donation from the thiophene-based compounds is always the dominant electron transfer process during adsorption, the backdonation of electrons from the 3d orbital of iron to σ*-antibonding orbitals of the thiophene compounds is also observed, especially in the case of π-3Fe parallel adsorption

  7. Benzimidazole as corrosion inhibitor for heat treated 6061 Al- SiCp composite in acetic acid

    NASA Astrophysics Data System (ADS)

    Chacko, Melby; Nayak, Jagannath

    2015-06-01

    6061 Al-SiCpcomposite was solutionizedat 350 °C for 30 minutes and water quenched. It was then underaged at 140 °C (T6 treatment). The aging behaviour of the composite was studied using Rockwell B hardness measurement. Corrosion behaviour of the underaged sample was studied in different concentrations of acetic acid and at different temperatures. Benzimidazole at different concentrations was used for the inhibition studies. Inhibition efficiency of benzimidazole was calculated for different experimental conditions. Thermodynamic parameters were found out which suggested benzimidazole is an efficient inhibitor and it adsorbed on to the surface of composite by mixed adsorption where chemisorption is predominant.

  8. Effect of tannin from Rhizophora apiculate as corrosion inhibitor for epoxy paint on mild steel

    NASA Astrophysics Data System (ADS)

    Idora, M. S. Noor; Quen, L. K.; Kang, H. S.

    2017-09-01

    There is a great concern to protect the steel surfaces from corrosion phenomenon in seawater environment. Several approaches have been proposed to introduce alternative new compounds in the paint which are green sources that can reduce environmental risks. The aim of this investigation was to enhance the protection properties of epoxy paint by providing an anticorrosive inhibitor for the paint. In this approach, the abilities of mangrove tannins, extracted from Rhizophora apiculata bark were studied. The inhibitive properties of mangrove tannins were evaluated by weight loss measurement, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). Results shows the addition of mangrove tannin in the coating boosted the anticorrosive properties of the paint and represents valuable environmentally friendly of inhibitor.

  9. Modeling corrosion inhibition efficacy of small organic molecules as non-toxic chromate alternatives using comparative molecular surface analysis (CoMSA).

    PubMed

    Fernandez, Michael; Breedon, Michael; Cole, Ivan S; Barnard, Amanda S

    2016-10-01

    Traditionally many structural alloys are protected by primer coatings loaded with corrosion inhibiting additives. Strontium Chromate (or other chromates) have been shown to be extremely effectively inhibitors, and find extensive use in protective primer formulations. Unfortunately, hexavalent chromium which imbues these coatings with their corrosion inhibiting properties is also highly toxic, and their use is being increasingly restricted by legislation. In this work we explore a novel tridimensional Quantitative-Structure Property Relationship (3D-QSPR) approach, comparative molecular surface analysis (CoMSA), which was developed to recognize "high-performing" corrosion inhibitor candidates from the distributions of electronegativity, polarizability and van der Waals volume on the molecular surfaces of 28 small organic molecules. Multivariate statistical analysis identified five prototypes molecules, which are capable of explaining 71% of the variance within the inhibitor data set; whilst a further five molecules were also identified as archetypes, describing 75% of data variance. All active corrosion inhibitors, at a 80% threshold, were successfully recognized by the CoMSA model with adequate specificity and precision higher than 70% and 60%, respectively. The model was also capable of identifying structural patterns, that revealed reasonable starting points for where structural changes may augment corrosion inhibition efficacy. The presented methodology can be applied to other functional molecules and extended to cover structure-activity studies in a diverse range of areas such as drug design and novel material discovery.

  10. Dianils: New and effective corrosion inhibitors for oil-well steel (N-80) and mild steel in boiling hydrochloric acid

    SciTech Connect

    Quraishi, M.A.; Jamal, D.

    2000-02-01

    Selected condensation products of aromatic aldehydes and p-phenylenediamine have been synthesized and evaluated as corrosion inhibitors for mild steel (MS) and oil-well steel (N-80) in 15% hydrochloric acid (HCl) at 105 C {+-} 2 C by the weight loss method. All the condensation products showed excellent performance. 2,4-dicinnamyledene aminophenylene (DCAP) was found to be the best corrosion inhibitor. It exhibited 99.75% inhibition efficiency (IE) for MS and 99.12% for N-80 steel at 5,000 ppm of inhibitor concentration. The potentiodynamic polarization studies carried out at room temperature on MS in 15% HCl containing 500 ppm of condensation products showed that all the investigated compounds were mixed type inhibitors, whereas 500 ppm DCAP on N-80 steel behaved predominantly as anodic inhibitors. The adsorption of all the condensation products was found to obey Temkin's adsorption isotherm.

  11. Effect of temperature on the corrosion inhibition of iron in liquid lead using oxygen inhibitor: studied by MD simulation

    NASA Astrophysics Data System (ADS)

    Arkundato, Artoto; Monado, Fiber; Su'ud, Zaki

    2017-05-01

    For corrosion mitigation of steels used in a fast nuclear reactor power plant, oxygen gas is one of promising candidates of inhibitors. Many experiments have been conducted to reveal the mechanism of corrosion and mechanism of how to overcome the corrosion. In the previous work, we had shown computationally that the oxygen atom can be used to reduce the corrosion and we had predicted the oxygen contents. In the current work, not only to explore deeeper the ability of oxygen gas to reduce the corrosion, but also to include the variation of used temperature. We still used iron material to represent a real steels. Using MD (molecular dynamics) simulation based on the Lennard-Jones interaction potential, we sought to understand the concentration of oxygen gas as variation of temperature used in the reactor for the best corrosion mitigation. From this work, we conclude that the temperature does not give effect in related with how concentration of injected oxygen. The temparature merely affects to rise the diffusion coefficient of iron in liquid lead, yet it does not influence how much oxygen needed for corrosion mitigation. In this work, all simulations on different series of temperatures (1023°K, 1073°K, 1123°K, 1173°K) reveals that oxygen content of 0.1151wt% will cause the lowest corrosion level of iron in liquid lead.

  12. Anaerobic digestion of aircraft deicing fluid wastes: interactions and toxicity of corrosion inhibitors and surfactants.

    PubMed

    Gruden, Cyndee L; Hernandez, Mark

    2002-01-01

    Corrosion inhibitors and surfactants are present in aircraft deicing fluids (ADFs) at significant concentrations (> 1% w/w). The purpose of this research was to study the interactions of a common nonionic surfactant with the commercially significant corrosion inhibitors used in modern ADF (4- and 5-methylbenzotriazole [MeBT]), and to determine the effects of their mixture on the conventional anaerobic digestion process. In mesophilic anaerobic microcosms codigesting wastewater solids, propylene glycol, and MeBT, increasing surfactant levels resulted in enhanced MeBT sorption on digester solids. As judged by anaerobic toxicity assays, responses from digesters containing surfactant concentrations below their critical micelle concentration (CMC) suggested that low nonionic surfactant concentrations could facilitate a reduction in the apparent toxicity of MeBT. In microcosms exposed to surfactant concentrations above their CMC, no increase in MeBT solubility was observed, and the anaerobic toxicity response corresponded to control systems not containing surfactant. Direct microscopic measurements of digesting biomass using fluorescent phylogenetic probes (fluorescent in situ hybridization) revealed that members of the domain Bacteria were more sensitive to MeBT in the presence of surfactant than were members of the domain Archaea.

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

    NASA Technical Reports Server (NTRS)

    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

  14. Adsorption and Corrosion Inhibition Studies of Some Selected Dyes as Corrosion Inhibitors for Mild Steel in Acidic Medium: Gravimetric, Electrochemical, Quantum Chemical Studies and Synergistic Effect with Iodide Ions.

    PubMed

    Peme, Thabo; Olasunkanmi, Lukman O; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-09-02

    The corrosion inhibition properties of some organic dyes, namely Sunset Yellow (SS), Amaranth (AM), Allura Red (AR), Tartrazine (TZ) and Fast Green (FG), for mild steel corrosion in 0.5 M HCl solution, were investigated using gravimetric, potentiodynamic polarization techniques and quantum chemical calculations. The results showed that the studied dyes are good corrosion inhibitors with enhanced inhibition efficiencies. The inhibition efficiency of all the studied dyes increases with increase in concentration, and decreases with increase in temperature. The results showed that the inhibition efficiency of the dyes increases in the presence of KI due to synergistic interactions of the dye molecules with iodide (I(-)) ions. Potentiodynamic polarization results revealed that the studied dyes are mixed-type inhibitors both in the absence and presence of KI. The adsorption of the studied dyes on mild steel surface, with and without KI, obeys the Langmuir adsorption isotherm and involves physical adsorption mechanism. Quantum chemical calculations revealed that the most likely sites in the dye molecules for interactions with mild steel are the S, O, and N heteroatoms.

  15. Corrosion resistance properties of organic inorganic hybrid coatings on 2024 aluminum alloy

    NASA Astrophysics Data System (ADS)

    Liu, Yan; Sun, Dezhi; You, Hong; Chung, Jong Shik

    2005-06-01

    Three kinds of organic-inorganic hybrid coatings modified by tetraethoxysilane (TEOS) were prepared using precursors of vinyltrimethoxysilane (VMS), [3-(methacryloxy)propyl] trimethoxysilane (MPMS) and (3-glycidoxyproyl) trimethoxysilane (GPMS). Properties of corrosion resistance were tested by potentiodynamic polarization curves. Salt spray test and SEM images were also employed to examine the ablitity of coatings to resist long-time corrosion. The results show that hybrid coatings are effective for inhibiting corrosion reaction. Corrosion currents of VMS coating and MPMS coating were 300 times smaller than that of bare sample. The corrosion current of hybrid coatings is smallest when TEOS content reaches 15-20%. It was found that VMS coatings have the strongest ability to resist salt spray corrosion.

  16. Effect of Inhibitor Agents Addition on Corrosion Resistance Performance of Titania Sol-Gel Coatings Applied on 304 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Shanaghi, Ali; Chu, Paul K.; Moradi, Hadi

    Hybrid organic-inorganic coatings are deposited on 304 stainless steel substrates by the sol-gel technique to improve the corrosion resistance. A titania-based nanostructured hybrid sol-gel coating is impregnated with three different microencapsulated healing agents (inhibitors) including cerium, Benzotriazole (BTA), and 8-Hydroxyquinoline (8H). Field-emission scanning electron microscopy (FE-SEM) and electrochemical impedance spectroscopy (EIS) are performed to investigate the barrier performance properties. The optimum conditions to achieve corrosion protective coatings for 304 stainless steel were determined. The Nyquist plots demonstrate that the activation time of the coating containing 8H as an organic healing agent shows improved behavior when compared to other coatings including cerium and BTA. Cerium as an inorganic healing agent is second and BTA is third and minimum. An increase in the impedance parameters such as resistance and capacitance as a function of immersion time is achieved in a 3.5wt.% NaCl solution by using healing agents such as BTA. Actually, over the course of immersion, the barrier performance behavior of the coatings changes and reduction of the impedance observed from the coatings containing Ce and 8H discloses deterioration of the protection system after immersion for 96h of immersion in the 3.5% NaCl solution. However, after 96h of immersion time, the concentration of chloride ions is high and causes increase in defects, micro cracks, hole on the surface of hybrid titania nanostructured coating containing Ce and 8H by destruction of coating, and also hybrid titania nanostructured coating containing BTA; BTA is released from coating to improve the resistance of passive film, which is created on the surface.

  17. The rate of iron corrosion for different organic carbon sources during biofilm formation.

    PubMed

    Park, S K; Choi, S C; Kim, Y K

    2007-01-01

    The effects of total organic carbon and biofilm on microbial corrosion were quantified using serum bottles in a 2 x 2 factorial design. Both organic carbon and biofilm bacteria had a significant effect on the iron corrosion rate, irrespective of the levels of the other variable (p = 0.05). There was no evidence of interaction between organic carbon and biofilm bacteria. Within the tested levels, the addition of exogenous organic carbon increased the corrosion rate by an average of 3.838 mg dm(-2) day(-1) (mdd), but the presence of biofilm bacteria decreased the rate by an average of 2.305 mdd. More iron was released from the coupon in response to organic carbon. Powder x-ray diffractometry indicated that the scales deposited on the corroded iron surface consisted primarily of lepidocrocite (gamma-FeOOH), magnetite (Fe3O4) and hematite (alpha-Fe203). Corrosion rates by different organic carbon sources, i.e. acetate, glucose and humic substances, were compared using an annular biofilm reactor. One-way ANOVA suggested that the effect of each carbon source on corrosion was not the same, with the iron corrosion rate highest for glucose, followed by acetate, humic substances and the control. Magnetite was a major constituent of the corrosion products scraped from iron slides. Examination of community-level physiological profile patterns on the biofilms indicated that acetate was a carbon source that could promote the metabolic and functional potentials of biofilm communities.

  18. Electrochemical evaluation of antibacterial drugs as environment-friendly inhibitors for corrosion of carbon steel in HCl solution

    NASA Astrophysics Data System (ADS)

    Golestani, Gh.; Shahidi, M.; Ghazanfari, D.

    2014-07-01

    The effect of penicillin G, ampicillin and amoxicillin drugs on the corrosion behavior of carbon steel (ASTM 1015) in 1.0 mol L-1 hydrochloric acid solution was investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. The inhibition efficiency was found to increase with increasing inhibitor concentration. The effect of temperature on the rate of corrosion in the absence and presence of these drugs was also studied. Some thermodynamic parameters were computed from the effect of temperature on corrosion and inhibition processes. Adsorption of these inhibitors was found to obey Langmuir adsorption isotherm. There was a case of mixed mode of adsorption here but while penicillin was adsorbed mainly through chemisorption, two other drugs were adsorbed mainly through physisorption. Potentiodynamic polarization measurements indicated that the inhibitors were of mixed type. In addition, this paper suggests that the electrochemical noise (EN) technique under open circuit conditions as the truly noninvasive electrochemical method can be employed for the quantitative evaluation of corrosion inhibition. This was done by using the standard deviation of partial signal (SDPS) for calculation of the amount of noise charges at the particular interval of frequency, thereby obtaining the inhibition efficiency (IE) of an inhibitor. These IE values showed a reasonable agreement with those obtained from potentiodynamic polarization and EIS measurements.

  19. High Performance Multifunctional Corrosion Inhibitors Especially for Combining at 20 to 50 Weight Percent with Soap or Paint.

    DTIC Science & Technology

    1987-12-22

    against general corrosion tions include sodium borate, sodium nitrite, sodium of many metals and alloys. 45 hexametaphosphate , sodium metasilicate... sodium ii- For nonchromate systems, a rather complex mixture trate and mercaptobenzothiazole in a predetermined is required to achieve such broad-based...compounds. These improved corro- sive contaminants such as sodium chloride. sion inhibiting formulations are particularly useful in Other inhibitor

  20. 1-Butyl-1-methylpyrrolidinium chloride as an effective corrosion inhibitor for stainless steel current collectors in magnesium chloride complex electrolytes

    NASA Astrophysics Data System (ADS)

    Ha, Jung Hoon; Cho, Jae-Hyun; Kim, Jong Hak; Cho, Byung Won; Oh, Si Hyoung

    2017-07-01

    Corrosion of current collectors is one of the most significant issues to tackle in rechargeable magnesium batteries where chloride-abundant electrolytes are commonly used since it can affect the electrochemical performance and the safety of battery system seriously. Here we investigate 1-butyl-1-methylpyrrolidinium chloride ionic liquid as an effective corrosion inhibitor of the current collector in an electrolyte containing magnesium chloride complex. We find that adding just 0.2 wt.% ionic liquid increases the anodic stability of common current collectors by 0.1-0.3 V while maintaining the coulombic efficiencies for Mg deposition and stripping at over 98%. In particular, analytical studies of the passive film formed on 316L stainless steel show that the inhibitor efficiently prevents the formation of corrosion pits and preserves the protective property of the passive film upon repeated anodic scans. Furthermore, the inhibitor enables almost 100% efficiencies in the full cell cycling with Mo6S8 cathode, reflecting higher anodic stability of the current collectors in the electrolyte containing the inhibitor. We propose that the formation of an adsorbed layer of the ionic liquid as a plausible corrosion inhibition mechanism.

  1. A new dioxime corrosion inhibitor for the protection and conservation of copper: synthesis, characterization and evaluation in acidic chloride solution

    NASA Astrophysics Data System (ADS)

    Abu-Baker, Ahmad N.; Al-Qudah, Mahmoud A.

    2016-08-01

    This study aimed to investigate a new dioxime compound as a corrosion inhibitor for copper. The compound (4,6-dihydroxy benzene-1,3-dicarbaldehyde dioxime) was synthesized and characterized by nuclear magnetic resonance spectroscopy. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements were used to compare the dioxime compound with benzotriazole for their effectiveness as corrosion inhibitors for copper in 0.1 M HCl solution. Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) were used to investigate the bonding mechanisms and morphological changes of the two inhibitors on the copper surface. The electrochemical techniques showed that the new dioxime compound was more effective than benzotriazole in inhibiting copper corrosion in the acidic chloride medium. The FTIR and SEM results indicated that the dioxime compound was able to coordinate with copper ions and formed a protective film on the copper surface. It was concluded that the new dioxime compound proved effectiveness to be used as a corrosion inhibitor for the protection and conservation of copper.

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

    SciTech Connect

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

    2009-10-01

    Dissolution of salt from Type III/IIIA waste tanks at the Savannah River Site may create solutions with inhibitor concentrations below those currently required (0.6M OH{sup -} and 1.1M OH{sup -} + NO{sub 2}{sup -}) per the Corrosion Control Program for high nitrate salt solutions (5.5 to 8.5M NO{sub 3}{sup -}). An experimental program was conducted to evaluate the corrosion susceptibility of grade A537 carbon steel for waste simulants containing 4.5-8.5M NaNO{sub 3} with maximum inhibitor concentrations of 0.6M NaOH and 0.2M NaNO{sub 2}. These maximum inhibitor concentrations used in this program are at a reduced level from those currently required. Current requirements were initially established for the Types I, II and IV tanks made of A285 carbon steel. The experimental program involved corrosion testing to evaluate the pitting and stress corrosion stress corrosion cracking (SCC) susceptibility of the Type III/IIIA waste tank materials. The program was conducted in two phases; the results of the first phase were reported previously (WSRC-STI-2006-00029). In this second phase, the corrosion specimens were modified to represent the 'as-fabricated' condition of the tank wall, and included specimens with mill scale, ground welds and stress-relief heat treatments. The complete description of the corrosion testing and the results are reported herein. The collective corrosion test results for A537 carbon steel in high nitrate waste simulants (4.5 - 8.5M) with the maximum inhibitor concentrations of 0.6M NaOH and 0.2M NaNO{sub 2} were as follows: (1) In long-term non-polarized U-bend testing, heat treatment, similar to the waste tank stress relief regime, reduced the incidence of cracking over the 18-month test period. Vapor space SCC was found to initiate on non-heat treated U-bend coupons. (2) In polarized U-bend testing, cracking occurred on U-bend coupons that had welds prepared similar to those in the waste tanks, i.e. ground and heat treated. (3) In electrochemical

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

    PubMed

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

    2012-11-01

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

  4. Carboxylates and sulfated carboxylates as inhibitors of steel corrosion in neutral media

    SciTech Connect

    Podobaev, N.I.; Larionov, E.A.

    1995-03-01

    Effects of carboxylates and sulfocarboxylates as well as their mixtures with o-nitrobenzoate on the corrosion of St3 steel in freely aerated distilled water and 0.01 - 0.04 M NaCl solutions (pH 7) are studied electrochemically and by the gravimetric technique. A noticeable improvement of the protective properties of sulfated mustard soap and sulfated castor oil is observed after the addition of 20 mg/l o-nitrobenzoate. Armco iron spontaneously passivates in 0.25 M CH{sub 3}COONa solution at a certain content of inhibitors and under a hydrodynamical regime. Sulfated carboxylates suppress the anodic process more strongly than do nonsulfated carboxylates.

  5. Study of Henna (Lawsonia inermis) as Natural Corrosion Inhibitor for Aluminum Alloy in Seawater

    NASA Astrophysics Data System (ADS)

    Nik, W. B. Wan; Zulkifli, F.; Sulaiman, O.; Samo, K. B.; Rosliza, R.

    2012-09-01

    Commercial henna (Lawsonia inermis) was investigated to inhibit the corrosion of aluminum alloy through immersion in seawater. The aluminum alloy (5083) was prepared in size of 25mm × 25mm × 3mm. The immersion test was conducted in seawater with different concentration of henna, 100ppm, 300ppm, 500ppm for duration of 60 days. Four characterizations were performed in this study which was weight loss study, Fourier Transform Infrared (FTIR), Electrochemical Impedance Spectroscopy (EIS) and adsorption isotherm. The results indicated that henna has major constituents of lawsone which contributed to the chemisorptions or adsorption process by forming an isolation layers on the aluminum alloy surface which follows the Langmuir adsorption isotherm. It was found that the protection layer attached on metal was not permanent and precipitation occurred as the time increases. The highest inhibition efficiency was found at 88% (500ppm). This research found that henna is an excellent natural inhibitor for aluminum alloy in seawater.

  6. Model boiler testing to evaluate inhibitors for caustic induced stress corrosion cracking of Alloy 600 tubes

    SciTech Connect

    Daret, J.; Paine, J.P.N.; Partridge, M.J.

    1995-12-31

    A series of model boiler tests, using a mixture of precracked and non-precracked (virgin) tube-to-tube support plate intersections was performed. The testing supported the qualification of inhibitors for mitigating the secondary side corrosion of alloy 600 steam generator tubes. Many utilities suspect that the caustic impurities come from the feedwater. Candidate inhibitors included boric acid (as a reference), cerous acetate, and two forms of titanium dioxide: a laboratory produced titania-silica sol-gel, and manometer sized anatase The latter was combined with a 150 C pre-soaking with a titanium lactate, and was tested with and without a zeta potential treatment by sodium aluminate. Effectiveness of boric acid to prevent and retard caustic induced intergranular corrosion was confirmed in all crevice configurations (open and packed). The cerous acetate treatment multiplied by two to four the time necessary to detect a primary-to-secondary leak on virgin tubes, and reduced the propagation rate on precracked tubes. Cerium was found intimately mixed, as cerianite, with the free span and crevice deposits, when the crevices were sufficiently accessible. Due to its very low solubility and large particle size, the titania-silica sol-gel was unable to penetrate the crevices and had no effect on the degradation process. The nanometric particle size titania treatment and/or the preceding soaking with soluble titanium lactate drastically increased the titanium concentration in free span and open crevice deposit (with no added sodium aluminate, titania reacted with magnetite to form ilmenite) and showed undeniable capacity to prevent tubing degradation. Its effectiveness, in the case of packed crevices and for arresting cracks, was not so conclusive.

  7. Dual active ionic liquids and organic salts for inhibition of microbially influenced corrosion.

    PubMed

    Seter, Marianne; Thomson, Melanie J; Stoimenovski, Jelena; MacFarlane, Douglas R; Forsyth, Maria

    2012-06-18

    We describe a series of novel compounds designed to combat the bacterial growth that leads to microbially induced corrosion on steel in the marine environment. A synergistic effect of the ionic components in these dual active organic salts is demonstrated.

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

    SciTech Connect

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

    2007-12-31

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

  9. Effect of storage time and natural corrosion inhibitor on carbohydrate and carboxylic acids content in canned tomato puree.

    PubMed

    Grassino, A Nincevic; Grabaric, Z; De Sio, F; Cacace, D; Pezzani, A; Squitieri, G

    2012-06-01

    In this research compositional changes of tinplate-canned tomato purées, with or without the addition of essential onion oil were investigated. The study was focused on the analyses of carbohydrates and carboxylic acids in two groups of canned samples (with or without nitrates) to determine whether their chemical composition was affected with storage time. The measurements were performed by high performance liquid chromatography, during six months of storage. The contents of glucose, fructose and two major organic acids, citric and malic, were found in the concentration range 1.77-1.97%, 1.86-2.09%, 0.60-0.75% and 0.23-0.30%, respectively, in all canned samples. Compared to carbohydrates and organic acids, amino acids were found in minor quantities, among them, as most abundant ones were glutamic acid, arginine, aspartic and γ-amino butyric acids. The results show that contents of carbohydrates and carboxylic acids are significantly affected by the change of storage time in majority of analyzed samples. The results also indicated that the influence of essential onion oil on composition of canned tomato purée is within the range of changes due to storage time measured for all other types of cans. Therefore the addition of essential onion oil as natural efficient corrosion inhibitor, as it was found in our previous work, can be recommended for canned tomato purée.

  10. Study of benzotriazole as corrosion inhibitors of carbon steel in chloride solution containing hydrogen sulfide using electrochemical impedance spectroscopy (EIS)

    SciTech Connect

    Solehudin, Agus; Nurdin, Isdiriayani

    2014-03-24

    Corrosion and inhibition studies on API 5LX65 carbon steel in chloride solution containing various concentrations of benzotriazole has been conducted at temperature of 70°C using Electrochemical Impedance Spectroscopy (EIS). Corroded carbon steel surface with and without inhibitor have been observed using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), and Energy Dispersive Spectroscopy (EDS). The objectives of this research are to study the performance of benzotriazole as corrosion inhibitors. The experimental results of carbon steel corrosion in 3.5% NaCl solution containing 500 mg/l H{sub 2}S at different BTAH concentrations showed that corrosion rate of carbon steel decreases with increasing of BTAH concentrations from 0 to 10 mmol/l. The inhibition efficiency of BTAH was found to be affected by its concentration. The optimum efficiency obtained of BTAH is 93% at concentration of 5 mmol/l. The result of XRD and EDS analysis reveal the iron sulfide (FeS) formation on corroded carbon steel surface without inhibitor. The EDS spectrum show the Nitrogen (N) bond on carbon steel surface inhibited by BTAH.

  11. Screening and Quantification of Aliphatic Primary Alkyl Corrosion Inhibitor Amines in Water Samples by Paper Spray Mass Spectrometry.

    PubMed

    Jjunju, Fred P M; Maher, Simon; Damon, Deidre E; Barrett, Richard M; Syed, S U; Heeren, Ron M A; Taylor, Stephen; Badu-Tawiah, Abraham K

    2016-01-19

    Direct analysis and identification of long chain aliphatic primary diamine Duomeen O (n-oleyl-1,3-diaminopropane), corrosion inhibitor in raw water samples taken from a large medium pressure water tube boiler plant water samples at low LODs (<0.1 pg) has been demonstrated for the first time, without any sample preparation using paper spray mass spectrometry (PS-MS). The presence of Duomeen O in water samples was confirmed via tandem mass spectrometry using collision-induced dissociation and supported by exact mass measurement and reactive paper spray experiments using an LTQ Orbitrap Exactive instrument. Data shown herein indicate that paper spray ambient ionization can be readily used as a rapid and robust method for in situ direct analysis of polymanine corrosion inhibitors in an industrial water boiler plant and other related samples in the water treatment industry. This approach was applied for the analysis of three complex water samples including feedwater, condensate water, and boiler water, all collected from large medium pressure (MP) water tube boiler plants, known to be dosed with varying amounts of polyamine and amine corrosion inhibitor components. Polyamine chemistry is widely used for example in large high pressure (HP) boilers operating in municipal waste and recycling facilities to prevent corrosion of metals. The samples used in this study are from such a facility in Coventry waste treatment facility, U.K., which has 3 × 40 tonne/hour boilers operating at 17.5 bar.

  12. Corrosion inhibition of mild steel in acidic media using newly synthesized heterocyclic organic molecules: Correlation between inhibition efficiency and chemical structure

    SciTech Connect

    Ouici, H. B. Guendouzi, A.; Benali, O.

    2015-03-30

    The corrosion inhibition of mild steel in 5% HCl solutions by some new synthesized organic compounds namely 3-(2-methoxyphenyl) 5-mercapto-1. 2. 4-triazole (2-MMT), 3-(3-methoxyphenyl) 5-mercapto-1. 2. 4-triazole (3-MMT) and 3-(2-hydroxyphenyl) 5-mercapto-1. 2. 4-triazole (2-HMT) was investigated using weight loss and potentiostatic polarization techniques. These measurements reveal that the inhibition efficiency obtained by these compounds increased by increasing their concentration. The inhibition efficiency follows the order 2-MMT >3-MMT >2-HMT. Polarization studies show that these compounds are of the mixed type but dominantly act as a cathodic inhibitors for mild steel in 5% HCl solutions. These inhibitors function through adsorption following Langmuir isotherm. Activation energy and Gibbs free energy for adsorption of inhibitors are calculated. Molecular modeling has been conducted to correlate the corrosion inhibition properties with the calculated quantum chemical parameters.

  13. Longan seed and peel as environmentally friendly corrosion inhibitor for mild steel in acid solution: Experimental and theoretical studies.

    PubMed

    Liao, Liu Li; Mo, Shi; Luo, Hong Qun; Li, Nian Bing

    2017-08-01

    Longan seed and peel were extracted and used for impeding the corrosion of mild steel in hydrochloric acid solution. Experimental analyses indicate that the water extract of Longan's seed and peel, a mixed type inhibitor, can be chemically adsorbed onto the steel surface, and its inhibition effect rises with increasing extract concentration. To understand the adsorption mechanism and the contributions of the four main compounds of the extract to corrosion protection effect, quantum chemical methods and infrared spectrum were also employed. Theoretically, four main antioxidant compounds were regarded as effective components in the water extract of Longan's seed and peel. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The use of morinda citrifolia as a green corrosion inhibitor for low carbon steel in 3.5% NaCl solution

    NASA Astrophysics Data System (ADS)

    Kusumastuti, Rahayu; Pramana, Rakhmad Indra; Soedarsono, Johny W.

    2017-03-01

    The effect and mechanism of green corrosion inhibitor of Morinda Citrifolia (Noni) toward low carbon steel material has been researched. The general background is to develop the cheap and eco-friendly corrosion inhibitor based on components taken from tropical plants that grow +in Indonesia. This research aims to determine the effectiveness of the use of the extracts of noni as green corrosion inhibitor of carbon steel material in aggressive environment. The medium applied for this experiment is 3.5% natrium chloride solution. The variation of the concentration and immersion time duration has been applied as the experimental parameters. All the work was done at room temperature. The corrosion rate was measured by electrochemical polarization method with CMS 600-Gamry instruments and weight loss. The adsorption of inhibitor into the metal surface, which induced bonding formation after immersion was observed by using FTIR method. Inhibition mechanism was observed by polarization curves and fitted by the Langmuir adsorption models. The experimental results show that the higher concentration of inhibitor increasing the inhibition effect. The optimum inhibition is obtained at 3 ppm noni fruit extract, after immersion for about 288 hours. The corrosion rates obtained was 1.385 mpy, with the inhibitor efficiency of 76.92%. The monolayer film is formed coating the surface material as a result of mixed type corrosion inhibitor behavior of Noni. It can be concluded that this green inhibitor is effective to be used for low carbon steel material.

  15. Investigation of Synthesized Sulfonated Melamine Formaldehyde as a Novel Corrosion Inhibitor for Mild Steel in Saline Environment

    NASA Astrophysics Data System (ADS)

    Sharifi, Zahra; Pakshir, Mahmoud; Mohamadi, Somayeh

    2015-02-01

    A water soluble compound named sulfonated melamine formaldehyde (SMF) was synthesized and its corrosion inhibition behavior was studied for carbon steel in 3.5% NaCl solution by polarization measurements and electrochemical impedance spectroscopy (EIS). SMF was characterized with hydrogen nuclear magnetic resonance spectroscopy and then its physical properties and corrosion prevention efficiencies were investigated. The corrosion behavior of SMF was found to be dependent strongly on the electric nature of functional groups which are present in its structure. The decrease in ( i corr) and the increase in inhibition efficiency (% IE) with increasing the SMF concentrations proves that it protects C-steel in 3.5% NaCl solution from being corroded and Nyquist diagrams indicate that increasing charge transfer resistance is associated with a decrease in the capacitance and increase in the percentage inhibition efficiency. The decrease in capacitance values could be attributed to the adsorption of the inhibitor molecules at the metal surface by increasing the concentration of inhibitor in the solution the inhibition efficiency increased and the best inhibition was obtained at 1000 ppm inhibitor concentration. The scanning electron microscope was used to investigate the surface morphology of specimens in the absence and presence of inhibitor compound.

  16. Influence of IFKhANGAZ-1 inhibitor on crack growth in corrosion fatigue of steel in a hydrogen sulfide-containing medium

    SciTech Connect

    Shipilov, S.A.

    1987-11-01

    The authors present results of their investigation of the influence of hydrogen sulfide on crack growth in the corrosion fatigue of 32Kh3NMFA steel in a 3 percent NaCl solution and of the protective properties of the title inhibitor as well as its influence on the role of hydrogen embrittlement in corrosion fatigue crack propagation.

  17. Complexes of Imidazole with Poly(ethylene glycol) as a Corrosion Inhibitor for Carbon Steel in Sulphuric Acid

    NASA Astrophysics Data System (ADS)

    Salimi, Saeed; Nasr-Esfahani, Mojtaba; Umoren, Saviour A.; Saebnoori, Ehsan

    2015-12-01

    The inhibiting action of polyethylene glycol and imidazole (PEG/IMZ)) complexes prepared by a simple deprotonation procedure on carbon steel corrosion in 0.5 mol/L sulphuric acid was evaluated using the weight loss, potentiodynamic polarization, and electrochemical impedance spectroscopy techniques complemented by surface analysis using scanning electron microscopy. The inhibiting effect of the PEG/IMZ complexes on carbon steel corrosion was compared with the non-complex forms. Results obtained show that PEG/IMZ complex is a very effective corrosion inhibitor of carbon steel in the acid environment. The inhibition efficiency increased with the increase in the temperature and also with increasing percentage of imidazole in the complex. Corrosion inhibition occurs by virtue of adsorption of PEG/IMZ complexes on the steel surface which was found to follow the Temkin adsorption isotherm model. The PEG/IMZ complexes function as a mixed-type inhibitor. Results from all the methods employed are in a reasonably good agreement.

  18. Erosion-corrosion in carbon dioxide saturated systems in presence of sand, inhibitor, oil, and high concentration of salt

    NASA Astrophysics Data System (ADS)

    Hassani, Shokrollah

    Oil and gas production is usually accompanied by formation water which typically contains high levels of chloride. Some effects of chloride concentration on corrosion are not widely known in the literature, and this can result in misleading conclusions. One goal of this research was to contribute to a better understanding of the effects of chloride concentration in CO2 corrosion. Experimental and theoretical studies conducted in the present work have shown that increasing the NaCl concentration in solution has three important effects on corrosion results. First, standard pH meter readings in high NaCl concentration solutions require corrections. Second, increasing the NaCl concentration decreases the CO2 concentration in solution and therefore contributes to a decrease in the corrosion rate. Third, increasing the NaCl concentration increases the solubility of FeCO3 and therefore reduces the likelihood of forming an iron carbonate scale. High NaCl concentration also decreases the sand erosion rate of the metal slightly by increasing the density and viscosity of the liquid. There are two main contributions of this research. The first contribution is the experimental characterization of inhibited erosion-corrosion behavior of mild steel under CO2-saturated conditions with a high salt concentration. Chemical inhibition is one the most important techniques for controlling erosion-corrosion in offshore mild steel pipelines, tubing and pipe fittings in oil and gas industry. The second contribution is the introduction of a new approach for predicting inhibited erosion-corrosion in mild steel pipes including the effects of flow and environmental conditions, sand production, and an oil phase. Sand erosion can decrease the efficiency of corrosion protection systems including iron-carbonate scale formation and chemical inhibition. The need to be able to predict inhibitor performance under sand production conditions is particularly acute when the wells are deep or off

  19. Corrosion inhibition mechanisms of aluminum alloy 2024-T3 by selected non-chromate inhibitors

    NASA Astrophysics Data System (ADS)

    Lopez-Garrity, Omar A.

    The pursuit to find a chromate-alternative has led to the development of several chromate-free aerospace primers and coating systems that offer good protection. However, fundamental understanding of the functionality of the chromate-free pigments that are embedded within these coating systems is lacking. The objective of this study was to understand the fundamental mechanism of corrosion inhibition of aluminum alloy 2024-T3 by molybdate (MoO 42-), silicate (SiO32-), and praseodymium (Pr3+) with the goal of developing the kind of understanding that was accomplished for chromate. Furthermore, since most inhibiting conversion coatings and pigments act by releasing soluble species into the local environment, it was of interest to understand the mechanism of inhibition in aqueous 0.1 M NaCl solution. The mechanism of inhibition of AA2024-T3 by the select non-chromate inhibitors was investigated using various electrochemical, microscopic and spectroscopic techniques. Naturally aerated polarization curves showed that molybdate provided mixed inhibition in near-neutral pH and at a threshold concentration of 0.1 M. The largest effect was a 250 mV increase in the breakdown potential associated with pitting and a 350 mV decrease in the open-circuit potential (OCP). In addition, electrochemical impedance indicated that the corrosion inhibition mechanism is oxygen-dependent owing to the protection afforded by Mo(VI) species. It was proposed that the corrosion inhibition of AA2024-T3 by molybdate may occur following a two-step process whereby molybdate is rapidly reduced to MoO.(OH)2 over the intermetallic particles and is subsequently oxidized to intermediate molybdenum oxides (e.g. Mo4O11) in the presence of oxygen which is reduced. This in turn may lead to a local acidification, promoting the condensation and polymerization of molybdate species in solution to form polymolybdate species (Mo7O24 6- and Mo8O264-). Furthermore, S-phase particle dissolution is decreased

  20. Study on improvement of durability for reinforced concrete by surface-painting migrating corrosion inhibitor and engineering application

    NASA Astrophysics Data System (ADS)

    Song, Ning; WANG, Zixiao; LIU, Zhiyong; Zhou, Jiyuan; Zheng, Duo

    2017-01-01

    The corrosion currents of steel bar in concrete with three W/B and four chloride contents after surface-painting two migrating corrosion inhibitors (PCI-2015 and MCI-A) 14d to 150d in atmospheric condition were measured. The results showed that the corrosion current density (I corr) of steel bar reduced to 0.1 μA.cm-2 from the initial highest 3.833 μA.cm-2 (W/B=0.65, NaCl-1%) after surface-painting PCI-2015 14 d, and the I corr was still lower than 0.1 μA.cm-2 until 150d. The compressive strength and chloride migration coefficient of concrete specimens were tested. The possible reasons of the mechanisms of durability improvement for reinforced concrete by applying PCI-2015 inhibitor were PCI-2015 may be reacted with calcium hydroxide in cement concrete and lots of inhibitor particles may be adsorbed on the active sites first and then a stable protective layer may be formed. The I corr of steel bars in a hydraulic aqueduct concrete structure after painting PCI-2015, MCI-A (the United States) and MCI-B (Europe) during 6 months was monitored by Gecor 8 tester. The results showed that the average values of I corr of steel bars after painting the PCI-2015 150d fulfilled the specification requirements in “Design code for concrete structure strengthening (E.3) ”(GB 50367-2013).

  1. Preparation and application of crosslinked poly(sodium acrylate)--coated magnetite nanoparticles as corrosion inhibitors for carbon steel alloy.

    PubMed

    Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; El-Saeed, Ashraf M

    2015-01-14

    This work presents a new method to prepare poly(sodium acrylate) magnetite composite nanoparticles. Core/shell type magnetite nanocomposites were synthesized using sodium acrylate as monomer and N,N-methylenebisacrylamide (MBA) as crosslinker. Microemulsion polymerization was used for constructing core/shell structures with magnetite nanoparticles as core and poly(sodium acrylate) as shell. Fourier transform infrared spectroscopy (FTIR) was employed to characterize the nanocomposite chemical structure. Transmittance electron microscopy (TEM) was used to examine the morphology of the modified poly(sodium acrylate) magnetite composite nanoparticles. These particle will be evaluated for effective anticorrosion behavior as a hydrophobic surface on stainless steel. The composite nanoparticles has been designed by dispersing nanocomposites which act as a corrosion inhibitor. The inhibition effect of AA-Na/magnetite composites on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). Polarization measurements indicated that the studied inhibitor acts as mixed type corrosion inhibitor. EIS spectra exhibit one capacitive loop. The different techniques confirmed that the inhibition efficiency reaches 99% at 50 ppm concentration. This study has led to a better understanding of active anticorrosive magnetite nanoparticles with embedded nanocomposites and the factors influencing their anticorrosion performance.

  2. Corrosion mitigation of N-(2-hydroxy-3-trimethyl ammonium)propyl chitosan chloride as inhibitor on mild steel.

    PubMed

    Sangeetha, Y; Meenakshi, S; SairamSundaram, C

    2015-01-01

    The biopolymer N-(2-hydroxy-3-trimethyl ammonium)propyl chitosan chloride (HTACC) was synthesised and its influence as a novel corrosion inhibitor on mild steel in 1M HCl was studied using gravimetric and electrochemical experiments. The compound obtained was characterised using FTIR and NMR studies. The inhibition efficiency increased with the increase in concentration and reached a maximum of 98.9% at 500 ppm concentration. Polarisation studies revealed that HTACC acts both as anodic and cathodic inhibitor. Electrochemical impedance studies confirmed that the inhibition is through adsorption on the metal surface. The extent of inhibition exhibits a negative trend with increase in temperature. Langmuir isotherm provides the best description on the adsorption nature of the inhibitor. SEM analysis indicated the presence of protective film formed by the inhibitor on the metal surface.

  3. The influence of inhibitor Na2CrO4 and NaNO3 on corrosion and micro structure on AISI 348 steel material

    NASA Astrophysics Data System (ADS)

    Samosir, Rahmad; Budiarto; Simanjuntak, Sutan L. M. H.

    2017-09-01

    The influence of inhibitor Na2CrO4 and NaNO3 on corrotion and microstructure on AISI 348 steel material have been carried out. A series of corrosion tests were conducted with polarization and potentiodynamic and microstructure resistance methods on AISI steel 348 for secondary cooling pipes at steam power plants. This research was carried out in demineralized water at room temperature (25°C) using Na2CrO4 and NaNO3 inhibitors whose concentration varied between 0-150 ppm for corrosion rate inhibitors. Observations of microstructures were performed using optical microscopy and SEM. The corrosion test showed that in the NaNO3 inhibitor solution, the highest corrosion rate was 0.05 mpy at 15 ppm and the lowest corrosion rate was 0.0058 mpy at 30 ppm, and the highest tail was 174.89 mV at 75 ppm and the lowest tail 103, 04 mV at concentration 0 ppm. While in Na2CrO4 inhibitor solution obtained the highest corrosion rate 0,0606 mpy at concentration 75 ppm and lowest corrosion rate 0,0197 mpy at concentration 15 ppm, and highest tail 264 mV at concentration 30 ppm and lowest tail -128 mV at concentration 75 ppm from Inhibitor Na2CrO4. The optimum concentration of NaNO3 was 30 ppm with an efficiency of 72.1%, and the optimum concentration of Na2CrO4 was 150 ppm with an efficiency of 1.9%. The result of microstructure observation showed that on the surface of the sample was formed a protective film of oxide, and on corrosion of AISI 348 steel corrosion of well form.

  4. Influence of respiratory substrate in carbon steel corrosion by a Sulphate Reducing Prokaryote model organism.

    PubMed

    Dall'agnol, Leonardo T; Cordas, Cristina M; Moura, José J G

    2014-06-01

    Sulphate Reducing Prokaryotes (SRP) are an important group of microorganisms involved in biocorrosion processes. Sulphide production is recognized as a fundamental cause of corrosion and nitrate is often used as treatment. The present work analyses the influence of respiratory substrates in the metal, from off-shore installations, SRP influenced corrosion, using Desulfovibrio desulfuricans ATTC 27774 as model organism, since this can switch from sulphate to nitrate. Open Circuit Potential over 6days in different conditions was measured, showing an increase around 200 and 90mV for the different media. Tafel plots were constructed allowing Ecorr and jcorr calculations. For SRP in sulphate and nitrate media Ecorr values of -824 and -728mV, and jcorr values of 2.5 and 3.7μAcm(-2), respectively, were attained indicating that in nitrate, the resultant corrosion rate is larger than in sulphate. Also, it is shown that the equilibrium of sulphide in the solution/gas phases is a key factor to the evolution of corrosion Nitrate prevents pitting but promotes general corrosion and increases the corrosion potential and iron dissolution 40 times when compared to sulphate. Our results demonstrate that nitrate injection strategy in oil fields has to be considered carefully as option to reduce souring and localized corrosion.

  5. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    SciTech Connect

    Bill W. Bogan; Brigid M. Lamb; John J. Kilbane II

    2004-10-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed to determine if chemical compounds other than pepper extracts could inhibit the growth of corrosion-associated microbes and to determine if pepper extracts and other compounds can inhibit corrosion when mature biofilms are present. Several chemical compounds were shown to be capable of inhibiting the growth of corrosion-associated microorganisms, and all of these compounds limited the amount of corrosion caused by mature biofilms to a similar extent. It is difficult to control corrosion caused by mature biofilms, but any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion.

  6. Quinoxaline derivatives as corrosion inhibitors for mild steel in hydrochloric acid medium: Electrochemical and quantum chemical studies

    NASA Astrophysics Data System (ADS)

    Olasunkanmi, Lukman O.; Kabanda, Mwadham M.; Ebenso, Eno E.

    2016-02-01

    The corrosion inhibition potential of four quinoxaline derivatives namely, 1-[3-(4-methylphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Me-4-PQPB), 1-(3-(4-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl)butan-1-one (Mt-4-PQPB), 1-[3-(3-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Mt-3-PQPB) and 1-[3-(2H-1,3-benzodioxol-5-yl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Oxo-1,3-PQPB) was studied for mild steel corrosion in 1 M HCl solution using electrochemical, spectroscopic techniques and quantum chemical calculations. The results of both potentiodynamic polarization and electrochemical impedance spectroscopic studies revealed that the compounds are mixed-type inhibitors and the order of corrosion inhibition efficiency at 100 ppm is Me-4-PQPB>Mt-3-PQPB>Oxo-1,3-PQPB>Mt-4-PQPB. Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopic analyses confirmed the presence of chemical interactions between the inhibitors and mild steel surface. The adsorption of the inhibitor molecules on mild steel surface was found to be both physisorption and chemisorption but predominantly chemisorption. The experimental data obey Langmuir adsorption isotherm. Scanning electron microscopy studies revealed the formation of protective films of the inhibitors on mild steel surface. Quantum chemical parameters obtained from density functional theory (DFT) calculations support experimental results.

  7. Effects of Orocol TL (a corrosion inhibitor) on germination and growth of bush beans

    SciTech Connect

    Parr, P.D.

    1982-04-01

    As part of a continuing series of studies conducted to determine the environmental effects of hexavalent chromium from cooling tower drift on biological systems, the potential for germination and growth effects in bush beans (Phaseolus vulgaris L. var Bush Blue Lake) from hexavelent chromium in Orocol TL (a proprietary chromated, zinc-phosphate compound added to DOE cooling water systems for corrosion inhibition) was investigated at low and high concentrations in the soil by adjusting soil pH and the percent of organic matter. Germination effects were determined in bean plants grown in soils adjusted to differing pH range (4-4.5, 5-5.5, 6.5-7), levels of organic matter (1.8%, 3%, 5%) and Orocol TL amendments (control of 0 ..mu..g/g, 10 ..mu..g/g chromium). Growth responses (effects) were determined from bush bean plants cultured in the same soil treatment combinations as described for the germination study. Plants were harvested when the plant died or at the end of eight weeks and partitioned into leaves, stems and roots. Following weight determinations, the leaves, stems and roots were analyzed for total chromium content, and the results compared using analysis of variance and multiple comparison procedures. High levels (500 ..mu..g/g) of hexavalent chromium in soil (as Orocol TL) affected germination and growth, while a high level of organic matter significantly reduced chromium toxicity on germination. At lower chromium concentrations there was significant uptake by all plant parts, with a corresponding reduction in biomass of leaves. Consequently, adjustments of soil pH from 4.0 to 7.0 appear to have no significant effect on chromium uptake in plants. Increasing the organic matter level to 5%, while decreasing the toxicity of high chromium levels to germinating seed, did not affect chromium uptake.

  8. Technical note: Tall oil fatty acid anhydrides as corrosion inhibitor intermediates

    SciTech Connect

    Fischer, E.R.; Parker, J.E. III

    1997-01-01

    Anhydrides derived from tall oil fatty acids offer enhanced corrosion inhibition properties compared to traditional dimer/trimer acids. The chemistry of this intermediate, its use in corrosion inhibition for downhole applications, and the synthesis of novel oil- and water-soluble derivatives were studied.

  9. Organic-inorganic nanosystems designed for multiple metal corrosion inhibition

    NASA Astrophysics Data System (ADS)

    Stockley, Robert

    This research focuses on the refinement and discovery of environmentally friendly coatings of metals with increased durability and longer lifetimes as the goal. In the pursuit of an ideal, such as environmentally friendly coatings or "green chemistry," there are many obstacles that must be overcome. This is particularly true in the case of protecting magnesium and its alloys. The relatively low open circuit potential of magnesium makes it highly susceptible to galvanic corrosion when in contact with other metals. It is also easily oxidized when exposed to air or humid conditions and forms a loose hydroxide/oxide layer (Mg(OH)2/MgO). However, for all of its problems, the advantages to using magnesium far outweigh the disadvantages; if and only if, its natural tendency to corrode can be adequately controlled. Magnesium has a high strength to weight ratio, similar to that of glass, making it ideal for a vast array of commercial applications. Magnesium has a high electromagnetic shielding effect (-52.34 dB at 2.45/ GHz for AZ31), making it applicable not only to aircraft instrumentation, but structure as well, due to its low density (d = 1.48 g/cm3). The list of applications for magnesium and its alloys is extensive. Our research has provided insights into the prevention of magnesium corrosion and the applications of "green chemistry" to a metal used across a multitude of industries. Specifically, excellent results were obtained for the electrochemical impedance spectroscopy of LZ91 (magnesium alloy) which demonstrated an impedance of 1.0 x 1010 Ohms to 1.0 x 1011 Ohms. These results suggest our coatings display a pure capacitance behavior in the Bode plot. According to ASTM B117 testing (salt fog testing) the coating on LZ91 panels reached 120 hours, a period considered to be the equivalent of five years of real world conditions, without appreciable corrosion. The possible mechanism for this corrosion protection will also be discussed. These advancements are

  10. Experimental and theoretical studies of xanthan gum and its graft co-polymer as corrosion inhibitor for mild steel in 15% HCl

    NASA Astrophysics Data System (ADS)

    Biswas, Amrita; Pal, Sagar; Udayabhanu, G.

    2015-10-01

    Xanthan gum (XG) and its graft co-polymer have been investigated as corrosion inhibitors for mild steel in 15% HCl. Gravimetric analysis, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) methods were employed for investigating the effectiveness of these inhibitors. Results indicate that both the inhibitors are of mixed type and follow Langmuir adsorption isotherm. Scanning electron microscopy (SEM) study also confirmed the protection of the metal surface by XG and xanthan gum-graft-poly(acrylamide) (XG-g-PAM). Theoretical calculations using Density Functional Theory (DFT) were used to establish the correlation between the structure and corrosion protection efficiencies.

  11. A NEXAFS study of the bonding of corrosion inhibitors on ZnO(1 0 1 bar 0)

    NASA Astrophysics Data System (ADS)

    Walsh, J. F.; Dhariwal, H. S.; Gutiérrez-Sosa, A.; Lindsay, R.; Thornton, G.; Oldman, R. J.

    1995-05-01

    The orientation of benzotriazole and related molecules on ZnO (1 0 1 bar 0) has been studied using C and N K-edge near-edge X-ray absorption fine structure (NEXAFS). At sub-monolayer coverage, benzotriazole is found to adsorb in an upright geometry with the molecular plane within 35° of perpendicular to the substrate, as indicated by the polarization dependence of the π* resonances. Seven slightly different models of the bond geometry are consistent with the data. Indazole (C7H6N2), another corrosion inhibitor is found to bond in a similar manner. Related molecules, benzimidazole (C7H6N2) and 1-methyl benzotriazole (C7H7N3) are found not to be oriented at sub-monolayer coverage. In conjunction with multilayer data, this suggests a specific first-bonding-layer origin for the corrosion inhibition properties of benzotriazole.

  12. Green Brönsted acid ionic liquids as novel corrosion inhibitors for carbon steel in acidic medium.

    PubMed

    Cao, Shuyun; Liu, Dan; Zhang, Peng; Yang, Lixia; Yang, Peng; Lu, Hui; Gui, Jianzhou

    2017-08-18

    New ionic liquids with multiple Brönsted acid sites were synthesized in ≥98% yield, and their inhibiting properties for the corrosion of carbon steel in 0.5 M HCl solution had been evaluated using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss method, finally the possible inhibiting mechanism was proposed according to UV-visible spectroscopic measurements and surface analysis including SEM and XPS techniques. The designed cation structure of Brönsted acid ionic liquids (BAILs), with one phenyl and two imidazolium rings, makes them good mixed-type inhibitors via the adsorption of BAILs on the steel surface to suppress both anodic and cathodic processes, obeying Langmuir adsorption isotherm. As potential acid catalysts, BAILs show nice corrosion inhibiting performance in acidic medium regardless of their Brönsted acidity, which is of great significance to enlarge the industry applications of BAILs.

  13. Effect of organic acid on CO{sub 2} corrosion of carbon and Cr bearing steels

    SciTech Connect

    Ueda, Masakatsu; Takabe, Hideki

    1998-12-31

    The effect of organic acid on CO{sub 2} corrosion of carbon and Cr bearing steels was investigated. Acetic acid was considered as the organic acid. The temperature(T{sub max}), which gave a maximum corrosion rate, was observed on pure iron, and 1 and 2%Cr steels in the CO{sub 2} environment with 0.5% CH{sub 3}COOH as well as in the CO{sub 2} environment without CH{sub 3}COOH. The corrosion rate of these steels at T{sub max} extremely increased due to the addition of 0.5% CH{sub 3}COOH, but the T{sub max} did not change. In 9 and 13% Cr steels, the T{sub max} was observed in the CO{sub 2} environment without CH{sub 3}COOH, but did not in the CO{sub 2} environment with 5% CH{sub 3}COOH, and those corrosion rates continued to increase at the temperature above the T{sub max} in the CO{sub 2} environment without CH{sub 3}COOH. These corrosion behaviors were discussed from a viewpoint of pH and FeCO{sub 3} formation condition which was led from the calculated-equilibrium volubility of FeCO{sub 3} at elevated temperatures. Then, those were related to the acceleration of corrosion at the steel surface with heterogeneous FeCO{sub 3} film in pure iron, and 1 and 2% Cr steels, and the different formation behavior of corrosion products at the temperatures below and above 200 C in 9 and 13% Cr steels.

  14. TiO2 membranes for concurrent photocatalytic organic degradation and corrosion protection

    NASA Astrophysics Data System (ADS)

    Liang, Robert; Hatat-Fraile, Melisa; He, Horatio; Arlos, Maricor; Servos, Mark R.; Zhou, Y. Norman

    2015-10-01

    Organic contaminants and corrosion in water treatment effluents are a current global problem and the development of effective methods to facilitate the removal of organic contaminants and corrosion control strategies are required to mitigate this problem. TiO2 nanomaterials that are exposed to UV light can generate electron-hole pairs, which undergo redox reactions to produce hydroxyl radicals from adsorbed molecular oxygen. They hydroxyl radicals are able to oxidize organic contaminants in water. This same process can be used in conjunction to protect metals from corrosion via cathodic polarization. In this work, TiO2 nanomaterials were synthesized and electrophoretically deposited on conductive substrates to serve as films or membranes. An illuminated TiO2 film on a conductive surface served as the photoanode and assisted in the cathodic protection of stainless steel (SS304) and the degradation of organic pollutants, in this case glucose. This proof-of-concept relied on photoelectrochemical experiments conducted using a potentiostat and a xenon lamp illumination source. The open-circuit potential changes that determine whether a metal is protected from corrosion under illumination was observed; and the electrical characteristics of the TiO2 film or membrane under dark and arc lamp illumination conditions were also analyzed. Furthermore, the effect of organic contaminants on the photocathodic protection mechanism and the oxidation of glucose during this process were explored.

  15. Inhibitor effects of sodium benzoate on corrosion resistance of Al6061-B4C composites in NaCl and H3BO3 solutions

    NASA Astrophysics Data System (ADS)

    Rafi-ud-din; Shafqat, Q. A.; Shahzad, M.; Ahmad, Ejaz; Asghar, Z.; Rafiq, Nouman; Qureshi, A. H.; Syed, Waqar adil; asim Pasha, Riffat

    2016-12-01

    Sodium benzoate (SB) is used for the first time to inhibit the corrosion of Al6061-B4C composites in H3BO3 and NaCl solutions. Al6061100-x -x wt% B4C (x = 0, 5, and 10) composites are manufactured by a powder metallurgy route. The corrosion inhibition efficiency of SB is investigated as a function of the volume fractions of B4C particles by using potentiodynamic polarization and electrochemical impedance techniques. Without the use of an inhibitor, an increase of the B4C particles in the composite decreases the corrosion resistance of Al6061-B4C composites. It is found that SB is an efficient corrosion inhibitor for Al6061-B4C composites in both investigated solutions. The corrosion inhibition efficiency of SB increases with an increase in B4C content. Since SB is an adsorption type inhibitor, it is envisaged that an extremely thin layer of molecules adsorbs onto the surface and suppresses the oxidation and reduction. It is found that the inhibitor effect of SB is more pronounced in a H3BO3 environment than in NaCl solution. Further, the mechanism of corrosion inhibition by SB is illustrated by using optical and scanning electron microscopy of corroded samples. It is found that the adsorption of benzoate ions on the Al surface and its bonding with Al3+ ions forms a hydrophobic layer on top of the exposed Al surface, which enhances the protection against dissolved boride ions.

  16. Corrosion protection mechanism of polyaniline blended organic coating on steel

    SciTech Connect

    Sathiyanarayanan, S.; Jeyaram, R.; Muthukrishnan, S.; Venkatachari, G.

    2009-07-01

    Epoxy-coal tar coatings are widely used to protect steel structures exposed to marine atmosphere due to their good barrier property. However, the presence of micropores and microcracks formed during the coating formation leads to failure of the coating due to permeation of corrosive ions. In recent years, it has been established that the coatings containing polyaniline (PANI) is able to protect pinholes and defects due to its passivating ability. Hence, a study has been made on the effect of polyaniline content (1 and 3%) in epoxy-coal tar coating on the corrosion protection of steel in 3% NaCl solution by electrochemical impedance spectroscopy (EIS) studies. Both phosphate- and chloride-doped polyanilines were prepared by a chemical oxidative polymerization method. From EIS studies, it has been found that the resistance value of the coatings containing 1 and 3% phosphate-doped polyaniline and 3% chloride-doped polyaniline pigmented coatings are similar to 10{sup 9} {Omega} cm{sup 2} even after 90 days exposure to NaCl solution, which are two orders high in comparison to that of conventional coal tar epoxy coatings. Besides, the conducting state of polyaniline has been found to be decreased after exposure to NaCl solution due to redox property of PANI. X-ray photoelectron spectroscopy studies have shown that polyaniline forms a complex layer with iron beneath the coating along with iron oxide.

  17. A Study on Electrolytic Corrosion of Boron-Doped Diamond Electrodes when Decomposing Organic Compounds.

    PubMed

    Kashiwada, Takeshi; Watanabe, Takeshi; Ootani, Yusuke; Tateyama, Yoshitaka; Einaga, Yasuaki

    2016-03-02

    Electrolytic corrosion of boron-doped diamond (BDD) electrodes after applying a high positive potential to decompose organic compounds in aqueous solution was studied. Scanning electron microscopy images, Raman spectra, and glow discharge optical emission spectroscopy revealed that relatively highly boron-doped domains were primarily corroded and relatively low boron-doped domains remained after electrolysis. The corrosion due to electrolysis was observed especially in aqueous solutions of acetic acid or propionic acid, while it was not observed in other organic compounds such as formic acid, glucose, and methanol. Electron spin resonance measurements after electrolysis in the acetic acid solution revealed the generation of methyl radicals on the BDD electrodes. Here, the possible mechanisms for the corrosion are discussed. Dangling bonds may be formed due to abstraction of OH groups from C-OH functional groups by methyl radicals generated on the surface of the BDD electrodes. As a result, the sp(3) diamond structure would be converted to the sp(2) carbon structure, which can be easily etched. Furthermore, to prevent electrolytic corrosion during electrolysis, both the current density and the pH condition in the aqueous solution were optimized. At low current densities or high pH, the BDD electrodes were stable without electrolytic corrosion even in the acetic acid aqueous solution.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  19. Cysteine as a green corrosion inhibitor for Cu37Zn brass in neutral and weakly alkaline sulphate solutions.

    PubMed

    Radovanović, Milan B; Petrović, Marija B; Simonović, Ana T; Milić, Snežana M; Antonijević, Milan M

    2013-07-01

    The aim of this study was to investigate electrochemical properties of brass in neutral and weakly alkaline solutions in the presence of cysteine as a nontoxic and ecological corrosion inhibitor. Potentiodynamic measurements, open circuit potential measurements, as well as chronoamperometric measurements were the methods used during investigation of the inhibitory effect of cysteine on the corrosion behaviour of brass. Potentiodynamic measurements showed that cysteine behaves as a mixed-type inhibitor in the investigated media. Based on polarization curves for brass in a weakly alkaline solution of sodium sulphate at varying cysteine concentrations, an interaction occurs between Cu(+) ions and the inhibitor, resulting in the formation of a protective complex on the electrode surface. The results of chronoamperometric measurements confirm the results obtained by potentiodynamic measurements. Optical microphotography of the brass surface also confirms the formation of a protective film in the presence of a 1 × 10(-4) mol/dm(3) cysteine. Adsorption of cysteine on the brass surface proceeds according to the Langmuir adsorption isotherm.

  20. Studies on a Few Substituted Piperidin-4-one Oximes as Corrosion Inhibitor for Mild Steel in HCl

    NASA Astrophysics Data System (ADS)

    Senthilkumar, A. N.; Tharini, K.; Sethuraman, M. G.

    2011-08-01

    The corrosion inhibition of mild steel in 1 M hydrochloric acid by a few piperidin-4-one oxime derivatives, namely, 1,3-dimethyl-2,6-diphenyl piperidin-4-one oxime ( I), 3,3-dimethyl-2,6-diphenyl piperidin-4-one oxime ( II), and 3-isopropyl-2,6-diphenyl piperidin-4-one oxime ( III) was studied using chemical weight loss method, electrochemical polarization and impedance spectroscopy, SEM with EDS, XRD, FT-IR measurements, and semi-empirical AM1 method for electronic properties. The weight loss measurements at four different temperatures such as 30, 40, 50, and 60 °C showed that the percentage inhibition efficiency (IE) of these compounds increased with increase of concentration and decreased with increase of temperature. The IE followed the order III < II < I. It was found that these inhibitors function through physical adsorption mechanism obeying Temkin's isotherm. Polarization studies showed that these compounds act as mixed-type inhibitors. Impedance measurements revealed the increase of charge transfer resistance with inhibitor concentration. Surface analysis using SEM, XRD, and FT-IR revealed the formation of protective film over the mild steel surface. The electronic properties calculated using AM1 semi-empirical method explained the inhibition characteristics. The quantum chemical studies showed that ring nitrogen and phenyl rings are the probable active centers to inhibit corrosion process.

  1. Novel Schiff-base molecules as efficient corrosion inhibitors for mild steel surface in 1 M HCl medium: experimental and theoretical approach.

    PubMed

    Saha, Sourav Kr; Dutta, Alokdut; Ghosh, Pritam; Sukul, Dipankar; Banerjee, Priyabrata

    2016-07-21

    In order to evaluate the effect of the functional group present in the ligand backbone towards corrosion inhibition performances, three Schiff-base molecules namely, (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)pyridine (L(1)), (E)-4-(2-(pyridin-4-ylmethylene)hydrazinyl)benzonitrile (L(2)) and (E)-4-((2-(2,4-dinitrophenyl)hydrazono)methyl)phenol (L(3)) were synthesized and used as corrosion inhibitors on mild steel in 1 M HCl medium. The corrosion inhibition effectiveness of the studied inhibitors was investigated by weight loss and several sophisticated analytical tools such as potentiodynamic polarization and electrochemical impedance spectroscopy measurements. Experimentally obtained results revealed that corrosion inhibition efficiencies followed the sequence: L(3) > L(1) > L(2). Electrochemical findings showed that inhibitors impart high resistance towards charge transfer across the metal-electrolyte interface and behaved as mixed type inhibitors. Scanning electron microscopy (SEM) was also employed to examine the protective film formed on the mild steel surface. The adsorption as well as inhibition ability of the inhibitor molecules on the mild steel surface was investigated by quantum chemical calculation and molecular dynamic (MD) simulation. In quantum chemical calculations, geometry optimized structures of the Schiff-base inhibitors, electron density distribution in HOMO and LUMO and Fukui indices of each atom were employed for their possible mode of interaction with the mild steel surfaces. MD simulations revealed that all the inhibitors molecules adsorbed in parallel orientation with respect to the Fe(110) surface.

  2. Electrochemical Study of AISI C1018 Steel in Methanesulfonic Acid Containing an Acetylenic Alcohol-Based Corrosion Inhibitor Formulation.

    PubMed

    Finšgar, Matjaž; Jackson, Jennifer

    2016-10-01

    In this work, the electrochemical potentiodynamic behavior of AISI C1018 lower-grade steel material was investigated in 20 wt.% methanesulfonic acid (MSA) solutions with or without different components to design corrosion inhibitor formulations based on acetylenic alcohol, cinnamaldehyde, 1-dodecylpyridinium chloride, and methanol. MSA has recently been considered as a new potential acid to be used in the matrix stimulation procedure and in well cleaning. It is demonstrated that AISI C1018 steel MSA needs to be inhibited. Inhibition type is determined for single components as well as for formulations. © 2015 Society for Laboratory Automation and Screening.

  3. Valoniopsis pachynema Extract as a Green Inhibitor for Corrosion of Brass in 0.1 N Phosphoric Acid Solution

    NASA Astrophysics Data System (ADS)

    Selva Kumar, R.; Chandrasekaran, V.

    2016-04-01

    The effect of marine alga Valoniopsis pachynema extract on corrosion inhibition of brass in phosphoric acid was investigated by weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy studies. The inhibition efficiency is found to increase with increasing concentration of extract and decreases with rise in temperature. The activation energy, thermodynamic parameters (free energy, enthalpy, and entropy change) and kinetic parameters (rate constant and half-life) for inhibition process were calculated. These thermodynamic and kinetic parameters indicate a strong interaction between the inhibitor and the brass surface. The inhibition is assumed to occur via adsorption of inhibitor molecules on brass surface, which obeys Temkin adsorption isotherm. The adsorption of inhibitor on the brass surface is exothermic, physical, and spontaneous, and follows first-order kinetics. The polarization measurements showed that the inhibitor behaves as a mixed type inhibitor and the higher inhibition surface coverage on the brass was predicted. Inhibition efficiency values were found to show good trend with weight-loss method, potentiodynamic polarization, and electrochemical impedance spectroscopy studies. Surface study techniques (FT-IR and SEM) were carried out to ascertain the inhibitive nature of the algal extract on the brass surface.

  4. Characterizing Corrosion Effects of Weak Organic Acids Using a Modified Bono Test

    NASA Astrophysics Data System (ADS)

    Zhou, Yuqin; Turbini, Laura J.; Ramjattan, Deepchand; Christian, Bev; Pritzker, Mark

    2013-12-01

    To meet environmental requirements and achieve benefits of cost-effective manufacturing, no-clean fluxes (NCFs) or low-solids fluxes have become popular in present electronic manufacturing processes. Weak organic acids (WOAs) as the activation ingredients in NCFs play an important role, especially in the current lead-free and halogen-free soldering technology era. However, no standard or uniform method exists to characterize the corrosion effects of WOAs on actual metallic circuits of printed wiring boards (PWBs). Hence, the development of an effective quantitative test method for evaluating the corrosion effects of WOAs on the PWB's metallic circuits is imperative. In this paper, the modified Bono test, which was developed to quantitatively examine the corrosion properties of flux residues, is used to characterize the corrosion effects of five WOAs (i.e., abietic acid, succinic acid, glutaric acid, adipic acid, and malic acid) on PWB metallic circuits. Experiments were performed under three temperature/humidity conditions (85°C/85% RH, 60°C/93% RH, and 40°C/93% RH) using two WOA solution concentrations. The different corrosion effects among the various WOAs were best reflected in the testing results at 40°C and 60°C. Optical microscopy was used to observe the morphology of the corroded copper tracks, and scanning electron microscopy (SEM) energy-dispersive x-ray (EDX) characterization was performed to determine the dendrite composition.

  5. Comparative study on lithium borates as corrosion inhibitors of aluminum current collector in lithium bis(fluorosulfonyl)imide electrolytes

    NASA Astrophysics Data System (ADS)

    Park, Kisung; Yu, Sunghun; Lee, Chulhaeng; Lee, Hochun

    2015-11-01

    Lithium bis(fluorosulfonyl)imide (LiFSI) is a promising salt that can possibly overcome the limitations of lithium hexafluorophosphate (LiPF6) in current Li-ion batteries (LIBs). Aluminum (Al) corrosion issue, however, is a major bottleneck for the wide use of LiFSI. This study investigates lithium borate salts as Al corrosion inhibitors in LiFSI electrolytes. Through a systematic comparison among lithium tetrafluoroborate (LiBF4), lithium bis(oxalato)borate (LiBOB), and lithium difluoro(oxalato)borate (LiDFOB), and LiPF6, the inhibition ability of the additives is revealed to be in the following order: LiDFOB > LiBF4 ≈ LiPF6 > LiBOB. In particular, the inhibition effect of LiDFOB is outstanding; the anodic behavior of Al in 0.8 M LiFSI + 0.2 M LiDFOB ethylene carbonate (EC)-based electrolyte is comparable to that of corrosion-free 1 M LiPF6 solution. The superior inhibition ability of LiDFOB is attributed to the formation of a passive layer composed of Al-F, Al2O3, and B-O species, as evidenced by X-ray photoelectron spectroscopy (XPS) measurements. A LiCoO2/graphite cell with 0.8 M LiFSI + 0.2 M LiDFOB electrolyte exhibits a rate capability comparable to a cell with 1 M LiPF6 solution, whereas a cell with 0.8 M LiFSI solution without LiDFOB suffers from poor power performance resulting from severe Al corrosion.

  6. EVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    SciTech Connect

    Bill W. Bogan; Wendy R. Sullivan; Kristine M. H. Cruz; Kristine L. Lowe; John J. Kilbane II

    2004-04-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing of pepper extracts resulted in preliminary data indicating that some pepper extracts inhibit the growth of some corrosion-associated microorganisms. This quarter additional tests were performed to more specifically investigate the ability of three pepper extracts to inhibit the growth, and to influence the metal corrosion caused by two microbial species: Desulfovibrio vulgaris, and Comomonas denitrificans. All three pepper extracts rapidly killed Desulfovibrio vulgaris, but did not appear to inhibit Comomonas denitrificans. While corrosion rates were at control levels in experiments with Desulfovibrio vulgaris that received pepper extract, corrosion rates were increased in the presence of Comomonas denitrificans plus pepper extract. Further testing with a wider range of pure bacterial cultures, and more importantly, with mixed bacterial cultures should be performed to determine the potential effectiveness of pepper extracts to inhibit MIC.

  7. Effect of halogens and inhibitors on the external stress corrosion cracking of Type 304 austenitic stainless steel

    SciTech Connect

    Whorlow, K.; Hutto, F.; Woolridge, E.

    1997-11-01

    The methodology of the drip procedure of the Standard Test Method for Evaluating the Influence of Thermal Insulation on External Stress Corrosion Cracking Tendency of Austenitic Stainless Steel (ASTM C 692-95a) was used to research the effect of halogens and inhibitors on the external stress corrosion cracking (ESCC) of Type 304 stainless steel as it applies to the insulation industry. Simulated insulation extraction solutions were made with pure chemical reagents for the halogens and inhibitors. The results indicated that sodium silicate compounds that were higher in sodium were more effective for preventing chloride-induced ESCC in Type 304 austenitic stainless steel. Potassium silicate was not as effective as sodium silicate. Fluoride, bromide, and iodide may cause ESCC but they were much less active than chloride and could be effectively inhibited by sodium silicate compound. The addition of fluoride ions to the chloride/sodium silicate systems, at the threshold of ESCC, appeared to have no synergistic effect. The ratio of sodium + silicate (mg/kg) to chloride (mg/kg) at the lower end of the RG 1.36 Acceptability Curve was not adequate to prevent ESCC using the methods of this research.

  8. An investigation of the effect of migratory type corrosion inhibitor on mechanical properties of zeolite-based novel geopolymers

    NASA Astrophysics Data System (ADS)

    Auqui, Nestor Ulloa; Baykara, Haci; Rigail, Andres; Cornejo, Mauricio H.; Villalba, Jose Luis

    2017-10-01

    The effects of migratory type corrosion inhibitor and curing time on the thermal stability and mechanical properties of Ecuadorian natural zeolite-based geopolymers were evaluated. Geopolymer samples were prepared by alkali activation of the natural zeolite by 8 M NaOH solution and calcium hydroxide Ca(OH)2 1-3 wt%, with an activator/binder ratio of 0.6. The geopolymer samples cured for 24 h at 40 °C and then for 6 days more at room temperature showed the compressive strength values in a range of 3-5,5 MPa. Mineralogical analysis of natural zeolite obtained by XRD is as follows: Mordenite (∼67%), quartz (∼27%) and amorphous (∼6%). SEM-EDS micrographs analysis of geopolymers revealed the presence of Na and Ca which proves the incorporation of the activators, NaOH and Ca(OH)2. The compressive strength values obtained indicate that the use of alkali activation of natural zeolites is an effective method for the synthesis of geopolymers. The mechanical properties of geopolymers were slightly but not adversely affected by the addition of the migratory corrosion inhibitor, MCI-2005 NS. These results will be used in future research on geopolymer concrete with embedded reinforcing steel.

  9. Investigation of SiO{sub 2}:Na{sub 2}O ratio as a corrosion inhibitor for metal alloys

    SciTech Connect

    Mohamad, N.; Othman, N. K.; Jalar, A.

    2013-11-27

    The silicate is one of the potential compounds used as a corrosion inhibitor for metal alloys. The mixture between silica and sodium hydroxide (NaOH) succeeded to produce the silicate product. The formulation of a silicate product normally variable depended by the different ratio of SiO{sub 2}:Na{sub 2}O. This research utilized the agriculture waste product of paddy using its rice husk. In this study, the amorphous silica content in rice husk ash was used after rice husk burnt in a muffle furnace at a certain temperature. The X-ray diffraction (XRD) analysis was done to determine the existence of amorphous phase of silica in the rice husk ash. There are several studies that recognized rice husk as an alternative source that obtained high silica content. The X-ray fluorescence (XRF) analysis was carried out to clarify the percentage amount of Si and O elements, which referred the silica compound in rice husk ash. The preparation of sodium silicate formulation were differ based on the SiO{sub 2}:Na{sub 2}O ratio (SiO{sub 2}:Na{sub 2}O ratio = 1.00, 2.00 and 3.00). These silicate based corrosion inhibitors were tested on several testing samples, which were copper (99.9%), aluminum alloy (AA 6061) and carbon steel (SAE 1045). The purpose of this study is to determine the appropriate SiO{sub 2}:Na{sub 2}O ratio and understand how this SiO{sub 2}:Na{sub 2}O ratio can affect the corrosion rate of each metal alloys immersed in acidic medium. In order to investigate this study, weight loss test was conducted in 0.5 M hydrochloric acid (HCl) for 24 hours at room temperature.

  10. Investigation of SiO2:Na2O ratio as a corrosion inhibitor for metal alloys

    NASA Astrophysics Data System (ADS)

    Mohamad, N.; Othman, N. K.; Jalar, A.

    2013-11-01

    The silicate is one of the potential compounds used as a corrosion inhibitor for metal alloys. The mixture between silica and sodium hydroxide (NaOH) succeeded to produce the silicate product. The formulation of a silicate product normally variable depended by the different ratio of SiO2:Na2O. This research utilized the agriculture waste product of paddy using its rice husk. In this study, the amorphous silica content in rice husk ash was used after rice husk burnt in a muffle furnace at a certain temperature. The X-ray diffraction (XRD) analysis was done to determine the existence of amorphous phase of silica in the rice husk ash. There are several studies that recognized rice husk as an alternative source that obtained high silica content. The X-ray fluorescence (XRF) analysis was carried out to clarify the percentage amount of Si and O elements, which referred the silica compound in rice husk ash. The preparation of sodium silicate formulation were differ based on the SiO2:Na2O ratio (SiO2:Na2O ratio = 1.00, 2.00 and 3.00). These silicate based corrosion inhibitors were tested on several testing samples, which were copper (99.9%), aluminum alloy (AA 6061) and carbon steel (SAE 1045). The purpose of this study is to determine the appropriate SiO2:Na2O ratio and understand how this SiO2:Na2O ratio can affect the corrosion rate of each metal alloys immersed in acidic medium. In order to investigate this study, weight loss test was conducted in 0.5 M hydrochloric acid (HCl) for 24 hours at room temperature.

  11. Evaluation of Inhibitors for Corrosion Control of Canadian Forces Ships’ Air Conditioning Hydronic Water Systems.

    DTIC Science & Technology

    1986-10-01

    par des chauffe-eau A vapeur pour le chauffage. Les groupes de climatisation a eau sont conqus pour 6tre construits en 6lments de cuivre ou...d’alliages de cuivre afin de r~duire la corrosion au minimum. Lors d’une inspection A la suite de l’obturation des cr~pines et petits orifices par de l’oxyde...de fer hydrat6, ce qui causait une perte de rendement, on a d~couvert que certaines pi~ces 6taient en acier doux. La corrosion des pieces en acier

  12. New coumarin derivative as an eco-friendly inhibitor of corrosion of mild steel in Acid medium.

    PubMed

    Al-Amiery, Ahmed A; Al-Majedy, Yasameen K; Kadhum, Abdul Amir H; Mohamad, Abu Bakar

    2014-12-29

    The anticorrosion ability of a synthesized coumarin, namely 2-(coumarin-4-yloxy)acetohydrazide (EFCI), for mild steel (MS) in 1 M hydrochloric acid solution has been studied using a weight loss method. The effect of temperature on the corrosion rate was investigated, and some thermodynamic parameters were calculated. The results indicated that inhibition efficiencies were enhanced with an increase in concentration of inhibitor and decreased with a rise in temperature. The IE value reaches 94.7% at the highest used concentration of the new eco-friendly inhibitor. The adsorption of inhibitor on MS surface was found to obey a Langmuir adsorption isotherm. Scanning electron microscopy (SEM) was performed on inhibited and uninhibited mild steel samples to characterize the surface. The Density Function theory (DFT) was employed for quantum-chemical calculations such as EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy) and μ (dipole moment), and the obtained results were found to be consistent with the experimental findings. The synthesized inhibitor was characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopic studies.

  13. Ammonium salts of polymaleic acids and use as corrosion inhibitors in water-in-oil emulsions

    SciTech Connect

    Oppenlaender, K.; Barthold, K.; Stork, K.

    1984-03-13

    The subject invention relates to salts of polymaleic acids having a molecular weight between 200 and 1500 and to their use in preventing the corrosion of metal caused by hydrogen sulfide and carbon dioxide in water-in-oil emulsions such as crude oil.

  14. Multicomponent Synthesis and Evaluation of New 1,2,3-Triazole Derivatives of Dihydropyrimidinones as Acidic Corrosion Inhibitors for Steel.

    PubMed

    González-Olvera, Rodrigo; Román-Rodríguez, Viridiana; Negrón-Silva, Guillermo E; Espinoza-Vázquez, Araceli; Rodríguez-Gómez, Francisco Javier; Santillan, Rosa

    2016-02-22

    An efficient one-pot synthesis of 1,2,3-triazole derivatives of dihydropyrimidinones has been developed using two multicomponent reactions. The aldehyde-1,2,3-triazoles were obtained in good yields from in situ-generated organic azides and O-propargylbenzaldehyde. The target heterocycles were synthesized through the Biginelli reaction in which the aldehyde-1,2,3-triazoles reacted with ethyl acetoacetate and urea in the presence of Ce(OTf)₃ as the catalyst. The corrosion inhibition of steel grade API 5 L X52 in 1 M HCl by the synthesized compounds was investigated using the electrochemical impedance spectroscopy technique. The measurements revealed that these heterocycles are promising candidates to inhibit acidic corrosion of steel.

  15. Comparison of organic peracids in wastewater treatment: Disinfection, oxidation and corrosion.

    PubMed

    Luukkonen, Tero; Heyninck, Tom; Rämö, Jaakko; Lassi, Ulla

    2015-11-15

    The use of organic peracids in wastewater treatment is attracting increasing interest. The common beneficial features of peracids are effective anti-microbial properties, lack of harmful disinfection by-products and high oxidation power. In this study performic (PFA), peracetic (PAA) and perpropionic acids (PPA) were synthesized and compared in laboratory batch experiments for the inactivation of Escherichia coli and enterococci in tertiary wastewater, oxidation of bisphenol-A and for corrosive properties. Disinfection tests revealed PFA to be a more potent disinfectant than PAA or PPA. 1.5 mg L(-1) dose and 2 min of contact time already resulted in 3.0 log E. coli and 1.2 log enterococci reduction. Operational costs of disinfection were estimated to be 0.0114, 0.0261 and 0.0207 €/m(3) for PFA, PAA and PPA, respectively. Disinfection followed the first order kinetics (Hom model or S-model) with all studied peracids. However, in the bisphenol-A oxidation experiments involving Fenton-like conditions (pH = 3.5, Fe(2+) or Cu(2+) = 0.4 mM) peracids brought no additional improvement to traditionally used and lower cost hydrogen peroxide. Corrosion measurements showed peracids to cause only a negligible corrosion rate (<6 μm year(-1)) on stainless steel 316L while corrosion rates on the carbon steel sample were significantly higher (<500 μm year(-1)).

  16. The corrosion protection of 2219-T87 aluminum by organic and inorganic zinc-rich primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

    1995-01-01

    The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electro-chemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. the galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 micro A/cm(exp 2) and 23.7 micro A/cm(exp 2) for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

  17. The Corrosion Protection of 2219-T87 Aluminum by Organic and Inorganic Zinc-Rich Primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.; Walsh, D. W.

    1995-01-01

    The behavior of zinc-rich primer-coated 2219-T87 aluminum in a 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR) were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electrochemical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 2219-T87 aluminum cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high galvanic current between the aluminum cathode and both zinc-rich primer anodes (37.9 pA/CM2 and 23.7 pA/CM2 for the organic and inorganic primers, respectively). The PR results demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application in the solid rocket booster aft skirt.

  18. The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

    SciTech Connect

    Hilca, B. R. Triyono

    2016-03-29

    This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO{sub 3}) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate content as inhibitor.

  19. The effect of inhibitor sodium nitrate on pitting corrosion of dissimilar material weldment joint of stainless steel AISI 304 and mild steel SS 400

    NASA Astrophysics Data System (ADS)

    Hilca, B. R.; Triyono

    2016-03-01

    This study experimentally evaluated the effect of Sodium Nitrate inhibitor (NaNO3) of 0.1%, 0.3%, and 0.5% on NaCl 3.5% toward pitting corrosion of dissimilar metal welding joint between stainless steel AISI 304 and mild steel SS 400. Electrochemical corrosion was tested using potentiodynamic polarization. Further the Scanning Electron Microscope (SEM) conducted to analyze the specimen. Chemical composition analysis used Energy Dispersive X-ray Spectrometry (EDS). The highest efficiency of sodium nitrate for ER 308 attained 63.8% and 64.89%for ER 309L. The specimen surface which observed through SEM showed decrease of pitting corrosion respectively with the addition of sodium nitrate content as inhibitor.

  20. A New Green Ionic Liquid-Based Corrosion Inhibitor for Steel in Acidic Environments.

    PubMed

    Atta, Ayman M; El-Mahdy, Gamal A; Al-Lohedan, Hamad A; Ezzat, Abdel Rahman O

    2015-06-17

    This work examines the use of new hydrophobic ionic liquid derivatives, namely octadecylammonium tosylate (ODA-TS) and oleylammonium tosylate (OA-TS) for corrosion protection of steel in 1 M hydrochloric acid solution. Their chemical structures were determined from NMR analyses. The surface activity characteristics of the prepared ODA-TS and OA-TS were evaluated from conductance, surface tension and contact angle measurements. The data indicate the presence of a double bond in the chemical structure of OA-TS modified its surface activity parameters. Potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements, scanning electron microscope (SEM), Energy dispersive X-rays (EDX) analysis and contact angle measurements were utilized to investigate the corrosion protection performance of ODA-TS and OA-TS on steel in acidic solution. The OA-TS and ODA-TS compounds showed good protection performance in acidic chloride solution due to formation of an inhibitive film on the steel surface.

  1. Pinhole corrosion of CH-TRU waste containers by volatile organic compounds

    SciTech Connect

    Zeek, D.P.

    1998-03-01

    In the spring of 1996 at the Idaho National Engineering and Environmental Laboratory Radioactive Waste Management Complex, an epidemic of corroded CH-TRU waste drums was encountered. The observed corrosion was in the form of rusty brown streaks that emanated from pinholes in about the upper one-third of the 55 gal drums. Wet streaks were tested as highly acidic by litmus paper. The liquid that emanated from the pinholes was found to be hydrochloric (HCl) acid. An investigation concluded that the pinholes were localized pitting corrosion caused by HCl acid formed in the drum headspace from reactions involving chlorinated volatile organic compounds (VOCs) in the waste and the unlined steel of the internal drum wall. The pinholes occurred in the upper parts of the drums because this corresponds to the internal headspace region above the rigid liner. Affected drums had a few to hundreds of pinholes with no detectable release of radioactivity. This was due to the internal packaging of waste in heavy polyethylene and/or polyvinyl chloride waste bags inside a rigid high-density polyethylene liner. The corrective action taken was to overpack pinhole corrosion drums into polyethylene-lined 83-gal drums and to test hundreds of drums with drum filters, but without pinhole corrosion, for the presence of HCl acid in the headspace gas with colorimetric tubes fitted to the drum filters. These colorimetric tubes contain a substance that changes color in reaction to HCl acid when headspace gas is drawn by a hand pump. Only drums that had a significant probability for the presence of HCl acid in the headspace were segregated in storage to allow ready inspection and efficient handling, if needed. It is recommended that any facility involved in the long-term storage of waste or other contents, that include chlorinated VOCs in unlined steel containers, be wary for the possible development of pinhole corrosion.

  2. The Activity of Trace Metals in Aqueous Systems and the Effect of Corrosion Control Inhibitors

    DTIC Science & Technology

    1975-10-01

    Polarography 10 Absorption Spectrophotometric Methods 15 Flame Photometer 16 III MATERIALS STUDIED 18 Ultrapure Water 18 Metals Studi,’ 25 The Corrosion...well known. Detailed water characterization defines the degree of water purity and/or contaminacion una iLs application in atomic absorption, flame ...dial positions are marked for suspended solids testing (infrared light range) and for the measurement of water color. 7. FLAME PHOTOMETER. The flame

  3. Introducing the Santolina chamaecyparissus Extract as a Suitable Green Inhibitor for 304 Stainless Steel Corrosion in Strong Acidic Medium

    NASA Astrophysics Data System (ADS)

    Shabani-Nooshabadi, Mehdi; Ghandchi, Maryam-Sadat

    2015-11-01

    The inhibitive action of extract of Santolina chamaecyparissus ( Santolina) as a green inhibitor on corrosion of 304 stainless steel (304 SS) in 6 M HCl solution was investigated by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy techniques, and scanning electron microscopic observations. The results of potentiodynamic polarization studies indicate that the extract shows mixed-type inhibition behavior and inhibition efficiency of 95.5 pct was achieved with the addition of 1.0 g L-1 extract. Impedance curves show that increasing Santolina concentration increases charge transfer resistance and decreases double-layer capacitance. The corrosion rate decreased with increasing concentration of extract and increased with the increase in temperature of the medium. The effect of temperature and related activation parameters was studied. Adsorption of the extract obeyed the Langmuir isotherm model. The negative value of the standard free energy of adsorption in the presence of the extract suggests the spontaneous adsorption of Santolina on 304 stainless steel surface. The inhibition efficiencies obtained from electrochemical tests were in good agreement with those obtained from weight loss measurements.

  4. Decrease in cytotoxicity of copper-based intrauterine devices (IUD) pretreated with 6-mercaptopurine and pterin as biocompatible corrosion inhibitors.

    PubMed

    Alvarez, Florencia; Grillo, Claudiaa; Schilardi, Patricial; Rubert, Aldo; Benítez, Guillermo; Lorente, Carolina; de Mele, Mónica Fernández Lorenzo

    2013-01-23

    The copper intrauterine device (IUD) based its contraceptive action on the release of cupric ions from a copper wire. Immediately after the insertion, a burst release of copper ions occurs, which may be associated to a variety of side effects. 6-Mercaptopurine (6-MP) and pterin (PT) have been proposed as corrosion inhibitors to reduce this harmful release. Pretreatments with 1 × 10(-4) M 6-MP and 1 × 10(-4) M PT solutions with 1h and 3h immersion times were tested. Conventional electrochemical techniques, EDX and XPS analysis, and cytotoxicity assays with HeLa cell line were employed to investigate the corrosion behavior and biocompatibility of copper with and without treatments. Results showed that copper samples treated with PT and 6-MP solutions for 3 and 1 h, respectively, are more biocompatible than those without treatment. Besides, the treatment reduces the burst release effect of copper in simulated uterine solutions during the first week after the insertion. It was concluded that PT and 6-MP treatments are promising strategies able to reduce the side effects related to the "burst release" of copper-based IUD without altering the contraceptive action.

  5. A Radical Pathway for Organic Phosphorylation during Schreibersite Corrosion with Implications for the Origin of Life

    NASA Technical Reports Server (NTRS)

    Pasek, Matthew A.; Dworkin, Jason P.; Lauretta, Dante S.

    2007-01-01

    Phosphorylated compounds (e.g. DNA, RNA, phospholipids, and many coenzymes) are critical to biochemistry. Thus, their origin is of prime interest to origin of life studies. The corrosion of the meteoritic mineral schreibersite ((Fe,Ni)3P) may have significantly contributed to the origin of phosphorylated biomolecules. Corrosion of synthetic schreibersite in a variety of solutions was analyzed by nuclear magnetic resonance spectroscopy, mass spectrometry, and electron paramagnetic resonance spectroscopy. These methods suggest a radical reaction pathway for the corrosion of schreibersite to form phosphite radicals (raised dot PO3 sup 2-)) aqueous solution. These radicals can form activated polyphosphates and can phosphorylate organic compounds such as acetate (3% yield). Phosphonates (O3P-C) are found in the organic P inventory of the carbonaceous meteorite Murchison. While phosphonates are rare in biochemistry, the ubiquity of corroding iron meteorites on the early Earth could have provided an accessible source of organophosphorous for the origin of life allowing the invention of the organophosphates in modern biology as a product of early evolution.

  6. Investigation of Diospyros Kaki L.f husk extracts as corrosion inhibitors and bactericide in oil field

    PubMed Central

    2013-01-01

    Background Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba-shan Mountain Area of Shannxi Province enable the investigating of new green oil field chemicals. Diospyros Kaki L.f (persimmon), a famous fruit tree is widely planted in Qin-ling and Ba-shan Mountain Area of Shaanxi Province. It has been found that the crude persimmon extracts are complex mixtures containing vitamins, p-coumaric acid, gallic acid, catechin, flavonoids, carotenoids and condensed tannin and so on, which indicates the extracts of persimmon husk suitable to be used as green and eco-friendly corrosion inhibitors. Findings Extracts of persimmon husk were investigated, by using weight loss and potentiodynamic polarisation techniques, as green and eco-friendly corrosion inhibitors of Q235A steel in 1M HCl. The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L. There are some synergistic effects between the extracts and KI, KSCN and HMTA. Potentiodynamic polarization studies indicate that extracts are mixed-type inhibitors. Besides, the extracts were screened for antibacterial activity against oil field microorganisms, and they showed good to moderate activity against SRB, IB and TGB. Conclusions The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L, and the highest reaches to 65.1% with the con concentration of 1,000 mg/L WE. KI, KSCN and HMTA they can enhance the IE of WE effectively to 97.3% at most, but not effective for KI and KSCN to AE. Tafel polarisation measurements indicate the extracts behave as mixed type inhibitor. Investigation of the antibacterial activity against

  7. Investigation of Diospyros Kaki L.f husk extracts as corrosion inhibitors and bactericide in oil field.

    PubMed

    Zhang, Jie; Song, Yingpan; Su, Huijun; Zhang, Li; Chen, Gang; Zhao, Jingrui

    2013-07-01

    Hydrochloric acid is used in oil-well acidizing commonly for improving the crude oil production of the low-permeable reservoirs, while it is a great challenge for the metal instruments involved in the acidification. Developing natural products as oilfield chemicals is a straight way to find less expensive, green and eco-friendly materials. The great plant resources in Qin-ling and Ba-shan Mountain Area of Shannxi Province enable the investigating of new green oil field chemicals. Diospyros Kaki L.f (persimmon), a famous fruit tree is widely planted in Qin-ling and Ba-shan Mountain Area of Shaanxi Province. It has been found that the crude persimmon extracts are complex mixtures containing vitamins, p-coumaric acid, gallic acid, catechin, flavonoids, carotenoids and condensed tannin and so on, which indicates the extracts of persimmon husk suitable to be used as green and eco-friendly corrosion inhibitors. Extracts of persimmon husk were investigated, by using weight loss and potentiodynamic polarisation techniques, as green and eco-friendly corrosion inhibitors of Q235A steel in 1M HCl. The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L. There are some synergistic effects between the extracts and KI, KSCN and HMTA. Potentiodynamic polarization studies indicate that extracts are mixed-type inhibitors. Besides, the extracts were screened for antibacterial activity against oil field microorganisms, and they showed good to moderate activity against SRB, IB and TGB. The inhibition efficiency of the extracts varied with extract concentration from 10 to 1,000 mg/L, and the highest reaches to 65.1% with the con concentration of 1,000 mg/L WE. KI, KSCN and HMTA they can enhance the IE of WE effectively to 97.3% at most, but not effective for KI and KSCN to AE. Tafel polarisation measurements indicate the extracts behave as mixed type inhibitor. Investigation of the antibacterial activity against oil field microorganism showed

  8. Corrosion inhibition in 2.0 M sulfuric acid solutions of high strength maraging steel by aminophenyl tetrazole as a corrosion inhibitor

    NASA Astrophysics Data System (ADS)

    Sherif, El-Sayed M.

    2014-02-01

    The corrosion of high strength maraging steel after varied immersion times in concentrated solution, 2.0 M, of sulfuric acid has been investigated. The work was also extended to study the effect of 5-(3-aminophenyl)-tetrazole (APTA) on the inhibition of the steel corrosion. The study has been carried out using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization and scanning electron microscope (SEM) along with energy dispersive X-ray analyzer (EDX) investigations. EIS spectra showed that the corrosion and polarization resistances decrease with increasing the immersion time of the steel before measurement and increase in the presence of APTA and the increase of its concentration. Polarization data agreed with the EIS measurements and indicated that the increase of immersion time increases the corrosion of steel by increasing its corrosion current and corrosion rate and lowering its polarization resistance. On the other hand, the addition of APTA and the increase of its concentration minimized the corrosion of steel through decreasing the corrosion current and corrosion rate and increasing the polarization resistance at all exposure test periods. SEM and EDX investigations confirmed that the inhibition of the maraging steel in the 2.0 M H2SO4 solutions is achieved via the adsorption of the APTA molecules onto the steel protecting its surface from being dissolved easily.

  9. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    SciTech Connect

    Kristine L. Lowe; Bill W. Bogan; Wendy R. Sullivan; Kristine Mila H. Cruz; Brigid M. Lamb; John J. Kilbane II

    2004-07-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed with mixed bacterial cultures obtained from natural gas pipelines. Treatment with the pepper extracts affected the growth and metabolic activity of the microbial consortia. Specifically, the growth and metabolism of sulfate reducing bacteria was inhibited. The demonstration that pepper extracts can inhibit the growth and metabolism of sulfate reducing bacteria in mixed cultures is a significant observation validating a key hypothesis of the project. Future tests to determine the effects of pepper extracts on mature/established biofilms will be performed next.

  10. Corrosion inhibitor storage and release property of TiO{sub 2} nanotube powder synthesized by rapid breakdown anodization method

    SciTech Connect

    Arunchandran, C.; Ramya, S.; George, R.P.; Kamachi Mudali, U.

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► TiO{sub 2} nanotube powders were synthesized by rapid breakdown anodization method. ► Benzotriazole was loaded into the TiO{sub 2} nanotube powders. ► Low pH induced release of benzotriazole from TiO{sub 2} nanotube powders was proved. -- Abstract: Titanium dioxide (TiO{sub 2}) is one of the most studied substances in material science due to its versatile properties and diverse applications. In this study titanium dioxide nanotube powder were synthesized by rapid breakdown anodization (RBA) method. The synthesis involved potentiostatic anodization of titanium foil in 0.1 M HClO{sub 4} electrolyte under an applied voltage of 20 V and rapid stirring. The morphology and the phase of titanium dioxide nanotube powder were studied using field emission scanning electron microscopy, laser Raman spectroscopy and high resolution transmission electron microscopy. Benzotriazole was chosen as model inhibitor to evaluate TiO{sub 2} nanotube powder's corrosion inhibitor loading and releasing properties. The storage and release properties of TiO{sub 2} nanotube powder were studied using UV–visible spectroscopy and thermogravimetric analysis.

  11. Environmentally Friendly Coating Technology for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Johnsey, Marissa N.; Jolley, Scott T.; Pearman, Benjamin P.; Zhang, Xuejun; Fitzpatrick, Lilliana; Gillis, Mathew; Blanton, Michael; hide

    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.

  12. Quantum chemical studies of some rhodanine azosulpha drugs as corrosion inhibitors for mild steel in acidic medium

    NASA Astrophysics Data System (ADS)

    Ebenso, Eno E.; Arslan, Taner; Kandemirli, Fatma; Caner, Necmettin; Love, Ian

    The density functional theory (DFT) at the B3LYP/6-31G (d,p) and B3LYP/6-311G(d,p) basis set levels and ab initio calculations using the HF/6-31G (d,p) and HF/6-311G(d,p) methods were performed on four rhodanine azosulpha drugs (namely 5-sulfadiazineazo-3-phenyl-2-thioxo-4-thiazolidinone, 5- sulfamethazineazo-3-phenyl-2-thioxo-4-thiazolidinone, 5-sulfadimethoxineazo-3-phenyl-2-thioxo- 4-thiazolidinone, and 5-sulfamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone) used as corrosion inhibitors for mild steel in acidic medium to determine the relationship between the molecular structure of the rhodanine azosulpha drugs and inhibition efficiency(%IE). The quantum chemical parameters/descriptors, namely, EHOMO (highest occupied molecular orbital energy), ELUMO (lowest unoccupied molecular orbital energy), the energy difference (ΔE) between EHOMO and ELUMO, dipole moment (μ), electron affinity (A), ionization potential (I), the absolute electronegativity (X), absolute hardness (η), softness (σ), polarizability (α), the Mulliken charges, and the fraction of electrons (ΔN) transfer from inhibitors to iron, were calculated and correlated with the experimental %IE. Quantitative structure activity relationship (QSAR) approach has been used, and a composite index of some quantum chemical parameters/descriptors was performed to characterize the inhibition performance of the studied molecules. The results showed that the inhibition efficiency (%IE) of the rhodanine azo sulfa drugs studied was closely related to some of the quantum chemical parameters/descriptors but with varying degrees of correlation coefficient (R2). The %IE also increased with the increase in EHOMO and decrease in EHOMO-ELUMO; and the areas containing N atoms are the most possible sites for bonding to the metal iron surface by donating electrons to the metal. The HOMO orbitals consist of 61.73-63.04% double bonded S atom (7(S)), and most of the rest are concentrated on the rhodanine group; so, the

  13. Products of the Black Sea alga Phyllophora nervosa as corrosion inhibitor for steel in acids

    SciTech Connect

    Popelyukh, G.M.; Andrianov, A.M.; Burtnenko, L.M.; Gazha, P.A.; Talavira, L.I.

    1986-05-01

    The authors have investigated the inhibiting properties of the processing products of the Black Sea red seaweed Phyllophora nervosa on specimens of steel St3 in phosphoric and hydrochloric acids of various concentrations at temperatures in the range from 30 to 95 /sup 0/C. They have studied how the concentrations of urotropin, sodium chloride, and Fe/sup 3 +/ ions influence the protective properties of the seaweed inhibitor. They have made preliminary investigations of the mechanisms of the protective action.

  14. Simple preparation of aminothiourea-modified chitosan as corrosion inhibitor and heavy metal ion adsorbent.

    PubMed

    Li, Manlin; Xu, Juan; Li, Ronghua; Wang, Dongen; Li, Tianbao; Yuan, Maosen; Wang, Jinyi

    2014-03-01

    By a simple and convenient method of using formaldehyde as linkages, two new chitosan (CS) derivatives modified respectively with thiosemicarbazide (TSFCS) and thiocarbohydrazide (TCFCS) were synthesized. The new compounds were characterized and studied by Fourier transform infrared spectroscopy, elemental analysis, thermal gravity analysis and differential scanning calorimetry, and their surface morphologies were determined via scanning electron microscopy. These CS derivatives could form pH dependent gels. The behavior of 304 steel in 2% acetic acid containing different inhibitors or different concentrations of inhibitor had been studied by potentiodynamic polarization test. The preliminary results show that the new compound TCFCS can act as a mixed-type metal anticorrosion inhibitor in some extent; its inhibition efficiency is 92% when the concentration was 60 mg/L. The adsorption studies on a metal ion mixture aqueous solution show that two samples TSFCS and TCFCS can absorb As (V), Ni (II), Cu (II), Cd (II) and Pb (II) efficiently at pH 9 and 4.

  15. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    SciTech Connect

    J. Robert Paterek; Gemma Husmillo

    2002-07-01

    The overall program objective is to develop and evaluate environmental benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is one or more environmental benign, a.k.a. ''green'' products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Capsicum sp. extracts and pure compounds were screened for their antimicrobial activity against MIC causing bacteria. Studies on the ability of these compounds to dissociate biofilm from the substratum were conducted using microtiter plate assays. Tests using laboratory scale pipeline simulators continued. Preliminary results showed that the natural extracts possess strong antimicrobial activity being comparable to or even better than the pure compounds tested against strains of sulfate reducers. Their minimum inhibitory concentrations had been determined. It was also found that they possess bactericidal properties at minimal concentrations. Biofilm dissociation activity as assessed by microtiter plate assays demonstrated varying degrees of differences between the treated and untreated group with the superior performance of the extracts over pure compounds. Such is an indication of the possible benefits that could be obtained from these natural products. Confirmatory experiments are underway.

  16. Determination of benzotriazole corrosion inhibitors from aqueous environmental samples by liquid chromatography-electrospray ionization-tandem mass spectrometry.

    PubMed

    Weiss, Stefan; Reemtsma, Thorsten

    2005-11-15

    The first method for the determination of commonly used corrosion inhibitors in environmental water samples by liquid chromatography-electrospray ionization-tandem mass spectrometry is presented. Benzotriazole (BTri) and the two isomers of tolyltriazole (5- and 4-TTri) are separated in an isocratic run. By gradient elution, BTri, 4-TTri, 5-TTri, and xylyltriazole can be determined simultaneously with three benzothiazoles, but here TTri isomers coelute. The instrumental detection limit of 2 pg allows the determination of the three most important benzotriazoles from municipal wastewater and most surface waters by direct injection into the HPLC system without previous enrichment. When solid-phase extraction is employed with mean recovery rates of 95-113%, the limit of quantification for benzotriazoles range from 10 ng/L in groundwater to 25 ng/L in untreated wastewater. BTri and TTri were determined in municipal wastewater in microgram per liter concentrations. Elimination in wastewater treatment appears to be poor, and BTri and TTri can be followed through a water cycle from treated municipal wastewater through surface water to bank filtrate used for drinking water production. The TTri isomers show markedly different biodegradation behavior with 4-TTri being more stable.

  17. Electrochemical and quantum chemical studies of N,N'-bis(4-hydroxybenzaldehyde)-2,2-dimethylpropandiimine Schiff base as corrosion inhibitor for low carbon steel in HCl solution.

    PubMed

    Jafari, Hojat; Danaee, Iman; Eskandari, Hadi; Rashvandavei, Mehdi

    2013-01-01

    A synthesized Schiff base N,N'-bis(4-hydroxybenzaldehyde)-2,2-dimethylpropandiimine (p-HBDP) was studied as green inhibitor for the corrosion of low carbon steel in 1 M HCl solution using electrochemical, surface and quantum chemical methods. Results showed that the inhibition occurs through the adsorption of the inhibitor molecules on the metal surface. The inhibition efficiency was found to increase with increasing inhibitor concentration and de-creased with increasing temper-ature, which is due to the fact that the rate of corrosion of steel is higher than the rate of adsorption. Thermodynamic parameters for adsorp-tion and activation processes were determined. Polarization data indicated that this compound act as mixed-type inhibitors and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. The calculations of reactivity indices of p-HBDP such as softness and natural charge distributions together with local reactivity by means of Fukui indices were used to explain the electron transfer mechanism between the p-HBDP molecules and the steel surface.

  18. Demonstration of multifunctional DNBM corrosion inhibitors in protective coatings for Naval Air/Weapon Systems. Final report, September 1989-July 1992

    SciTech Connect

    Bailin, L.J.

    1993-12-01

    The corrosion protective properties of multifunctional DNBM salts (quaternary ammonium dichromate, nitrate, borate, and molybdate) have been demonstrated on high-strength steel and aluminum alloys found in prototype aerospace weapon systems. The 100% DNBM mixture added to MIL-P-23377 epoxy-polyamide, minus strontium chromate inhibitor, on bare 7075-T6 aluminum alloy resisted 1000 h ASTM B-117 salt spray. However, the coatings were not resistant to hydraulic fluid immersion at the higher concentrations required for the corrosion inhibition. Microencapsulation of the reactive DNBM mixture was adopted as a means to prevent this susceptibility, as well as the destructive oxidation of the hydroxyl groups in the epoxy resin during cure. In the scale-up operation, approximately 20 gallons of DNBM weighing 64 kg (141 lb) was prepared from the four starting quarternary salts synthesized in a chemical process pilot plant. The salts were mixed by dissolving in toluene. Following removal of solvent, the resultant dark-brown liquid, approximating molasses in viscosity, was microencapsulated by the following method: The DNBM was dispersed to form an oil-in-water emulsion in an aqueous colloidal solution of low-viscosity, high-purity methyl cellulose using a Gifford-Wood homogenizer, followed by spray drying in an Anhydro spray dryer. The maximum practicable payload was 75% DNBM. After spray drying, the capsules Corrosion inhibitors, DNBM, Microencapsulation, Epoxy primers, Protective coatings.

  19. Effects of temperature and operation parameters on the galvanic corrosion of Cu coupled to Au in organic solderability preservatives process

    NASA Astrophysics Data System (ADS)

    Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Kim, JongSoo; Shon, MinYoung; Kwon, HyukSang

    2017-03-01

    In this work, we quantitatively examined the effects of temperature and operation parameters such as anode (Cu) to cathode (Au) area ratio, stirring speed, and Cu ion concentration on the galvanic corrosion kinetics of Cu coupled to Au (icouple ( Cu-Au)) on print circuit board in organic solderability preservative (OSP) soft etching solution. With the increase of temperature, galvanic corrosion rate (icouple ( Cu-Au) was increased; however, the degree of galvanic corrosion rate (icouple ( Cu-Au) - icorr (Cu)) was decreased owing to the lower activation energy of Cu coupled to Au, than that of Cu alone. With the increase of area ratio (cathode/anode), stirring speed of the system, icouple ( Cu-Au) was increased by the increase of cathodic reaction kinetics. And icouple ( Cu-Au) was decreased by the increase of the Cu-ion concentration in the OSP soft etching solution.

  20. Effects of temperature and operation parameters on the galvanic corrosion of Cu coupled to Au in organic solderability preservatives process

    NASA Astrophysics Data System (ADS)

    Oh, SeKwon; Kim, YoungJun; Jung, KiMin; Kim, JongSoo; Shon, MinYoung; Kwon, HyukSang

    2017-02-01

    In this work, we quantitatively examined the effects of temperature and operation parameters such as anode (Cu) to cathode (Au) area ratio, stirring speed, and Cu ion concentration on the galvanic corrosion kinetics of Cu coupled to Au (icouple (Cu-Au)) on print circuit board in organic solderability preservative (OSP) soft etching solution. With the increase of temperature, galvanic corrosion rate (icouple (Cu-Au) was increased; however, the degree of galvanic corrosion rate (icouple (Cu-Au) - icorr (Cu)) was decreased owing to the lower activation energy of Cu coupled to Au, than that of Cu alone. With the increase of area ratio (cathode/anode), stirring speed of the system, icouple (Cu-Au) was increased by the increase of cathodic reaction kinetics. And icouple (Cu-Au) was decreased by the increase of the Cu-ion concentration in the OSP soft etching solution.

  1. The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

    NASA Technical Reports Server (NTRS)

    Danford, M. D.; Mendrek, M. J.

    1995-01-01

    The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

  2. The use of a Phosphate-Based Migrating Corrosion Inhibitor to Repair Reinforced Concrete Elements Contaminated by Chlorides

    NASA Astrophysics Data System (ADS)

    Tittarelli, Francesca; Mobili, Alessandra; Bellezze, Tiziano

    2017-08-01

    The use of sodium monofluorophosphate (MFP) was experimented as migrator inhibiting treatment against corrosion of reinforced concrete elements induced by chlorides. The results show that sodium monofluorophosphate, applied by surface impregnation, is able to slow down reinforcement corrosion only for reinforcing steel bars with concrete cover not thicker than 1 cm. This limitation is most probably due to the difficulty, with the type of application adopted, in making MFP to reach concentrations high enough to inhibit the corrosive process at greater depths from the impregnation surface.

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

    NASA Astrophysics Data System (ADS)

    Ahmad, Zaki; Aleem, B. J. Abdul

    2009-03-01

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

  4. Entry Inhibitors: A Perspective for Prevention of Hepatitis C Virus Infection in Organ Transplantation.

    PubMed

    Colpitts, Che C; Chung, Raymond T; Baumert, Thomas F

    2017-09-08

    Entry inhibitors are emerging as an attractive class of therapeutics for hepatitis C virus (HCV) infection. Entry inhibitors target either virion-associated factors or cellular factors necessary for infection. By blocking entry into cells, entry inhibitors prevent both the establishment of persistent reservoirs and the emergence of resistant variants during viral replication. Furthermore, entry inhibitors protect naïve cells from virus-induced alterations. Combining entry inhibitors with direct-acting antivirals (DAAs) may therefore improve treatment outcomes, particularly in the context of organ transplantation. The role of DAAs in transplantation, while still under clinical investigation, carries the risk of recipient infection and HCV-induced disease, since DAAs act only after infection is established. Thus, entry inhibitors provide a perspective to improve patient outcomes during organ transplantation. Applying this approach for transplant of organs from HCV-positive donors to HCV-negative recipients may also contribute to alleviate the medical burden of organ shortage.

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

    SciTech Connect

    McCafferty, E.; Hansen, D.C.

    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.

  6. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    NASA Technical Reports Server (NTRS)

    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

  7. Electrochemical corrosion studies

    NASA Technical Reports Server (NTRS)

    Knockemus, W. W.

    1986-01-01

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

  8. Corrosion Behavior of Alloy 22 in Chloride Solutions Containing Organic Acids

    SciTech Connect

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

    2005-11-04

    Alloy 22 (N06022) is a nickel based alloy containing alloying elements such as chromium, molybdenum and tungsten. It is highly corrosion resistant both under reducing and under oxidizing conditions. Electrochemical studies such as electrochemical impedance spectroscopy (EIS) were performed to determine the corrosion behavior of Alloy 22 in 1M NaCl solutions at various pH values from acidic to neutral at 90 C. Tests were also carried out in NaCl solutions containing oxalic acid or acetic acid. It is shown that the corrosion rate of Alloy 22 was higher in a solution containing oxalic acid than in a solution of the same pH acidified with HCl. Acetic acid was not corrosive to Alloy 22. The corrosivity of oxalic acid was attributed to its capacity to form stable complex species with metallic cations from Alloy 22.

  9. Porphyrins as Corrosion Inhibitors.

    DTIC Science & Technology

    1984-07-01

    8. J. E. Drach and F. R. Longo, J. Org. Chem. 39 3282 (1974). 9. A. 0. Adler, F. R. Longo et al. J. Org. Chem. 32 376 (1967). 10. J. B. Kim, J. J...hypothesis, all failed. We did not obtain We wish to thank Dr. J. E. Drach for enlightening dis- 0-monobromoporphin when we treated porphin with cusaions...178 (1928). fled as 0-monobromoporphin. The mass spectra (Finnegan (6) J. E. Drach and F. R. Long. J. Org. Chem.. 39, 22 (1974). 39 NADC-84167-60 T

  10. Corrosion Protection of Nd-Fe Magnets via Phophatization, Silanization and Electrostatic Spraying with Organic Resin Composite Coatings

    NASA Astrophysics Data System (ADS)

    Ding, Xia; Li, Jingjie; Li, Musen; Ge, Shengsong; Wang, Xiuchun; Ding, Kaihong; Cui, Shengli; Sun, Yongcong

    2014-09-01

    Nd-Fe-B permanent magnets possess excellent properties. However, they are highly sensitive to the attack of corrosive environment. The aim of this work is to improve the corrosion resistance of the magnets by phosphatization, silanization, and electrostatic spraying with organic resin composite coatings. Field emission scanning electron microscope (FE-SEM) and energy dispersive spectrometer (EDS) tests showed that uniform phosphate conversion coatings and spray layers were formed on the surface of the Nd-Fe-B magnets. Neutral salt spray tests exhibited that, after treated by either phosphating, silanization or electrostatic spraying, the protectiveness of Nd-Fe-B alloys was apparently increased. And corrosion performance of magnets treated with silane only was slightly inferior to those of phosphatized ones. However, significant improvement in corrosion protection was achieved after two-step treatments, i.e. by top-coating spray layer with phosphate or silane films underneath. Grid test indicated that the phosphate and silane coating were strongly attached to the substrate while silane film was slightly weaker than the phosphate-treated ones. Magnetic property analysis revealed phosphatization, silanization, and electrostatic spraying caused decrease in magnetism, but silanization had the relatively smaller effect.

  11. Principles of inhibiting of corrosion-static crack growth in constructional steels caused by hydrogen embrittlement

    SciTech Connect

    Romaniv, O.N.; Nikiforchin, G.N.; Tsirul'nik, A.T.

    1987-11-01

    The effectiveness of a range of organic and inorganic corrosion inhibitors was studied on a series of structural chromium steels--including 45KhN2MFA, 60KhS, and 30KhGSN2A--of different strength levels and certain principles are formulated for developing and selecting inhibitors based on the hydrogen mechanism of corrosive media. The inhibitors tested include monoethanol amine, urotropin, sodium benzoate, thiourea, sodium phosphates and chromates, various nitrates, and the IRT range of inhibitors.

  12. Guar gum as efficient non-toxic inhibitor of carbon steel corrosion in phosphoric acid medium: Electrochemical, surface, DFT and MD simulations studies

    NASA Astrophysics Data System (ADS)

    Messali, M.; Lgaz, H.; Dassanayake, R.; Salghi, R.; Jodeh, S.; Abidi, N.; Hamed, O.

    2017-10-01

    Guar gum is a water-soluble, nonionic, nontoxic, biodegradable and biocompatible hetero polysaccharide with unlimited number of industrial applications. In this study, guar gum was evaluated as a natural inhibitor of carbon steel (CS) corrosion in 2 M H3PO4 solution. The characteristic effect of guar gum on the steel corrosion was studied at concentration ranges from 0.1 to 1.0 g/L at 298-328 K by weight loss and electrochemical methods. Obtained results showed that, the inhibition efficiency (η%) of guar gum decreased slightly when the temperature increased and increased by increasing the inhibitor concentration reaching the maximum value at 1.0 g/L. The adsorption of guar gum on steel surface was studied by the Temkin adsorption model. EIS measurements indicate that the values of the polarization resistance (Rp) of CS in presence of guar gum are significantly higher than that of the untreated surface. Steel surface coated with guar gum was analyzed by SEM, FTIR and XRD. The quantum calculations using DFT method and Molecular Dynamic (MD) simulations were performed to define the relationship between inhibition performance of investigated compound and their molecular structure.

  13. Electrochemical and quantum chemical calculations on 4,4-dimethyloxazolidine-2-thione as inhibitor for mild steel corrosion in hydrochloric acid

    NASA Astrophysics Data System (ADS)

    Musa, Ahmed Y.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar; Rahoma, Abdalhamid Ahmad B.; Mesmari, Hussein

    2010-04-01

    The inhibition ability of 4,4-dimethyloxazolidine-2-thione (DMT) for mild steel corrosion in a 1 M HCl solution at 30 °C was studied by means of potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) technique, and scanning electron microscopy (SEM). Quantum chemical calculation based on PM3 method was performed on DMT. The molecule structural parameters, such as the frontier molecular orbital energy HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), the charge distribution and the fraction of electrons (Δ N) transfer from inhibitor to mild steel were calculated and discussed. Results showed that DMT performed as good inhibiting effect for the corrosion of mild steel in a 1 M HCl solution and inhibition efficiency is higher than 82% at 4 × 10 -3 M DMT. Results indicate that the inhibition efficiencies increased with the concentration of DMT and the area containing S atom is most possible site for bonding the mild steel surface by donating electrons to the metal. Adsorption of the inhibitor on the mild steel surface followed Langmuir adsorption isotherm and the value of the free energy of adsorption Δ G○ads indicated that the adsorption of DMT molecule was a spontaneous process and was typical of chemisorptions.

  14. Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: synthesis, characterization, fluorescence and corrosion inhibitors of ligands.

    PubMed

    Ali, Omyma A M

    2014-11-11

    Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans. Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Palladium(II) and zinc(II) complexes of neutral [N2O2] donor Schiff bases derived from furfuraldehyde: Synthesis, characterization, fluorescence and corrosion inhibitors of ligands

    NASA Astrophysics Data System (ADS)

    Ali, Omyma A. M.

    2014-11-01

    Metal complexes of Schiff bases derived from furfuraldehyde and 4,5-dimethyl-1,2-phenylendiamine (L1) or 4,5-dichloro-1,2-phenylendiamine (L2) have been reported and characterized based on elemental analyses, IR, 1H NMR, UV-Vis, magnetic moment, molar conductance and thermal analysis. The complexes are found to have the formulae [PdL1-2]Cl2 and [ZnL1-2](AcO)2·H2O. The molar conductance data reveal that Pd(II) and Zn(II) chelates are ionic in nature and are of the type 2:1 electrolytes. The spectral data are consistent with a square planar and tetrahedral geometry around Pd(II) and Zn(II), respectively, in which the ligands act as tetradentate ligands. The thermal behavior of some chelates is studied and the activation thermodynamic parameters are calculated using Coats-Redfern method. The corrosion inhibition of stainless steel types 410 and 304 in 1 M HCl using the synthesized Schiff bases as inhibitors have been studied by weight loss method. The obtained data considered these ligands as efficient corrosion inhibitors. The ligands and their metal complexes exhibited considerable antibacterial activity against Staphylococcusaureus, and Escherichiacoli and antifungal activity against Candida albicans.

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

    PubMed

    Scully, John R

    2015-01-01

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

  17. Some Phthalocyanine and Naphthalocyanine Derivatives as Corrosion Inhibitors for Aluminium in Acidic Medium: Experimental, Quantum Chemical Calculations, QSAR Studies and Synergistic Effect of Iodide Ions.

    PubMed

    Dibetsoe, Masego; Olasunkanmi, Lukman O; Fayemi, Omolola E; Yesudass, Sasikumar; Ramaganthan, Baskar; Bahadur, Indra; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-08-28

    The effects of seven macrocyclic compounds comprising four phthalocyanines (Pcs) namely 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine (Pc1), 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine (Pc2), 2,9,16,23-tetra-tert-butyl-29H,31H-phthalocyanine (Pc3) and 29H,31H-phthalocyanine (Pc4), and three naphthalocyanines namely 5,9,14,18,23,27,32,36-octabutoxy-2,3-naphthalocyanine (nPc1), 2,11,20,29-tetra-tert-butyl-2,3-naphthalocyanine (nPc2) and 2,3-naphthalocyanine (nP3) were investigated on the corrosion of aluminium (Al) in 1 M HCl using a gravimetric method, potentiodynamic polarization technique, quantum chemical calculations and quantitative structure activity relationship (QSAR). Synergistic effects of KI on the corrosion inhibition properties of the compounds were also investigated. All the studied compounds showed appreciable inhibition efficiencies, which decrease with increasing temperature from 30 °C to 70 °C. At each concentration of the inhibitor, addition of 0.1% KI increased the inhibition efficiency compared to the absence of KI indicating the occurrence of synergistic interactions between the studied molecules and I(-) ions. From the potentiodynamic polarization studies, the studied Pcs and nPcs are mixed type corrosion inhibitors both without and with addition of KI. The adsorption of the studied molecules on Al surface obeys the Langmuir adsorption isotherm, while the thermodynamic and kinetic parameters revealed that the adsorption of the studied compounds on Al surface is spontaneous and involves competitive physisorption and chemisorption mechanisms. The experimental results revealed the aggregated interactions between the inhibitor molecules and the results further indicated that the peripheral groups on the compounds affect these interactions. The calculated quantum chemical parameters and the QSAR results revealed the possibility of strong interactions between the studied inhibitors and metal surface. QSAR analysis on the

  18. Large negatively charged organic host molecules as inhibitors of endonuclease enzymes.

    PubMed

    Tauran, Yannick; Anjard, Christophe; Kim, Beomjoon; Rhimi, Moez; Coleman, Anthony W

    2014-10-07

    Three large negatively charged organic host molecules; β-cyclodextrin sulphate, para-sulphonato-calix[6]arene and para-sulphonato-calix[8]arene have been shown to be effective inhibitors of endonuclease in the low micromolar range, additionally para-sulphonato-calix[8]arene is a partial inhibitor of rhDNase I.

  19. Effects of tobacco genetically modified to express protease inhibitor bovine spleen trypsin inhibitor on non-target soil organisms.

    PubMed

    O'Callaghan, Maureen; Brownbridge, Michael; Stilwell, Wendy B; Gerard, Emily M; Burgess, Elisabeth P J; Barraclough, Emma I; Christeller, John T

    2007-01-01

    Effects of tobacco genetically modified to express the protease inhibitor bovine spleen trypsin inhibitor (BSTI) were examined in laboratory assays against three earthworm and one collembolan species. BSTI is a serine protease inhibitor that can bind to the digestive trypsins of insects feeding on modified plants, resulting in reduced growth and survival. Protease inhibitors are active against a broad range of insects, so may have a large impact on non-target organisms. Survival and fecundity of the collembolan Folsomia candida were unaffected by consumption of artificial diet containing BSTI-expressing tobacco leaf or powdered freeze-dried BSTI-expressing tobacco leaf that was added to soil. Similarly, mortality and growth of earthworms Aporrectodea caliginosa and Lumbricus rubellus did not differ significantly between soil augmented with BSTI-expressing tobacco leaves or unmodified control leaves. The redworm Eisenia fetida gained less weight when provided with BSTI-expressing leaves in one assay, but when the experiment was repeated, there was no significant difference between treatments. BSTI-expressing tobacco and unmodified control leaves decomposed at the same rate, indicating that the inhibitor had no effect on the overall function of the decomposer community of micro-flora and fauna in soil.

  20. Antimony tartrate corrosion inhibitive composition for coolant systems

    SciTech Connect

    Payerle, N.E.

    1987-08-11

    An automobile coolant concentrate is described comprising (a) a liquid polyhydric alcohol chosen from the group consisting of ethylene glycol, propylene glycol, diethylene glycol and mixtures thereof, and (b) corrosion inhibitors in a corrosion inhibitory amount with respect to corrosion of lead-containing solders, the corrosion inhibitors comprising (i) an alkali metal antimony tartrate, and (ii) an azole compound.

  1. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  2. Electrodeposition of diamond-like carbon films on titanium alloy using organic liquids: Corrosion and wear resistance

    NASA Astrophysics Data System (ADS)

    Falcade, Tiago; Shmitzhaus, Tobias Eduardo; dos Reis, Otávio Gomes; Vargas, André Luis Marin; Hübler, Roberto; Müller, Iduvirges Lourdes; de Fraga Malfatti, Célia

    2012-12-01

    Diamond-like carbon (DLC) films have been studied as coatings for corrosion protection and wear resistance because they have excellent chemical inertness in traditional corrosive environments, besides presenting a significant reduction in coefficient of friction. Diamond-like carbon (DLC) films obtained by electrochemical deposition techniques have attracted a lot of interest, regarding their potential in relation to the vapor phase deposition techniques. The electrochemical deposition techniques are carried out at room temperature and do not need vacuum system, making easier this way the technological transfer. At high electric fields, the organic molecules polarize and react on the electrode surface, forming carbon films. The aim of this work was to obtain DLC films onto Ti6Al4V substrate using as electrolyte: acetonitrile (ACN) and N,N-dimethylformamide (DMF). The films were characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman spectroscopy, potentiodynamic polarization and wear tests. The results show that these films can improve, significantly, the corrosion resistance of titanium and its alloys and their wear resistance.

  3. Hydroxyethylcellulose used as an eco-friendly inhibitor for 1018 c-steel corrosion in 3.5% NaCl solution.

    PubMed

    El-Haddad, Mahmoud N

    2014-11-04

    The inhibition effect of hydroxyethylcellulose (HEC) on 1018 c-steel corrosion in 3.5% NaCl solution was investigated by using potentiodynamic polarization, electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization studies suggested that HEC acts as a mixed-type inhibitor. Data obtained from EIS were analyzed to model the corrosion inhibition process through equivalent circuit. Results obtained from EFM technique were shown to be in agreement with potentiodynamic and EIS techniques. The adsorption behavior of HEC on steel surface follows the Langmuir adsorption isotherm. Thermodynamic parameter (ΔG°(ads)) and activation parameters (Ea(*), ΔH(*) and ΔS(*)) were calculated to investigate mechanism of inhibition. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analysis system were performed to characterize the film formed on the metal surface. DMol(3) quantum chemical calculations were performed to support the adsorption mechanism with the structure of HEC molecule. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  4. Adsorption, Thermodynamic and Quantum Chemical Studies of 1-hexyl-3-methylimidazolium Based Ionic Liquids as Corrosion Inhibitors for Mild Steel in HCl

    PubMed Central

    Mashuga, Motsie E.; Olasunkanmi, Lukman O.; Adekunle, Abolanle S.; Yesudass, Sasikumar; Kabanda, Mwadham M.; Ebenso, Eno E.

    2015-01-01

    The inhibition of mild steel corrosion in 1 M HCl solution by some ionic liquids (ILs) namely, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate [HMIM][TfO], 1-hexyl-3-methylimidazolium tetrafluoroborate [HMIM][BF4], 1-hexyl-3-methylimidazolium hexafluorophosphate [HMIM][PF6], and 1-hexyl-3-methylimidazolium iodide [HMIM][I] was investigated using electrochemical measurements, spectroscopic analyses and quantum chemical calculations. All the ILs showed appreciably high inhibition efficiency. At 303 K, the results of electrochemical measurements indicated that the studied ILs are mixed-type inhibitors. The adsorption studies showed that all the four ILs adsorb spontaneously on steel surface with [HMIM][TfO], [HMIM][BF4] and [HMIM][I] obeying Langmuir adsorption isotherm, while [HMIM][PF6] conformed better with Temkin adsorption isotherm. Spectroscopic analyses suggested the formation of Fe/ILs complexes. Some quantum chemical parameters were calculated to corroborate experimental results.

  5. Porphyrins as Corrosion Inhibitors for N80 Steel in 3.5% NaCl Solution: Electrochemical, Quantum Chemical, QSAR and Monte Carlo Simulations Studies.

    PubMed

    Singh, Ambrish; Lin, Yuanhua; Quraishi, Mumtaz A; Olasunkanmi, Lukman O; Fayemi, Omolola E; Sasikumar, Yesudass; Ramaganthan, Baskar; Bahadur, Indra; Obot, Ime B; Adekunle, Abolanle S; Kabanda, Mwadham M; Ebenso, Eno E

    2015-08-18

    The inhibition of the corrosion of N80 steel in 3.5 wt. % NaCl solution saturated with CO2 by four porphyrins, namely 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (HPTB), 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (T4PP), 4,4',4″,4‴-(porphyrin-5,10,15,20-tetrayl)tetrakis(benzoic acid) (THP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) was studied using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, scanning electrochemical microscopy (SECM) and scanning electron microscopy (SEM) techniques. The results showed that the inhibition efficiency, η% increases with increasing concentration of the inhibitors. The EIS results revealed that the N80 steel surface with adsorbed porphyrins exhibited non-ideal capacitive behaviour with reduced charge transfer activity. Potentiodynamic polarization measurements indicated that the studied porphyrins acted as mixed type inhibitors. The SECM results confirmed the adsorption of the porphyrins on N80 steel thereby forming a relatively insulated surface. The SEM also confirmed the formation of protective films of the porphyrins on N80 steel surface thereby protecting the surface from direct acid attack. Quantum chemical calculations, quantitative structure activity relationship (QSAR) were also carried out on the studied porphyrins and the results showed that the corrosion inhibition performances of the porphyrins could be related to their EHOMO, ELUMO, ω, and μ values. Monte Carlo simulation studies showed that THP has the highest adsorption energy, while T4PP has the least adsorption energy in agreement with the values of σ from quantum chemical calculations.

  6. Corrosion Behavior of Copper Thin Films in Organic HF-Containing Cleaning Solution for Semiconductor Applications

    SciTech Connect

    Nabil G. Mistkawi,a,b Makarem A. Hussein,b Malgorzata Ziomek-Moroz,c and Shankar B. Rananavarea,z

    2009-11-13

    The corrosion behavior of electrochemically deposited copper thin films in deaerated and non-deaerated commercial cleaning solutions containing HF was investigated. Potentiodynamic polarization experiments were carried out to determine active, active-passive, passive, and transpassive regions. Corrosion rates were calculated from Tafel slopes. The addition of hydrogen peroxide to the solution and its influence on corrosion was also investigated by employing inductively coupled plasma-mass spectroscopy (ICP-MS) and X-ray photoelectron spectroscopy (XPS). The ICP-MS and potentiodynamic methods yielded comparable Cu dissolution rates. Surface analysis using atomic force microscopy and scanning electron microscopy, performed before and after the cleaning solution treatment, did not reveal any indication of pitting corrosion. The presence of hydrogen peroxide in the cleaning solution led to more than an order of magnitude suppression of copper dissolution rate. We ascribe this phenomenon to the formation of interfacial CuO detected by XPS on the wafer surface that dissolves at a slower rate in dilute HF.

  7. Corrosion and protection of heterogeneous cast Al-Si (356) and Al-Si-Cu-Fe (380) alloys by chromate adn cerium inhibitors

    NASA Astrophysics Data System (ADS)

    Jain, Syadwad

    In this study, the localized corrosion and conversion coating on cast alloys 356 (Al-7.0Si-0.3Mg) and 380 (Al-8.5Si-3.5Cu-1.6Fe) were characterized. The intermetallic phases presence in the permanent mold cast alloy 356 are primary-Si, Al5FeSi, Al8Si6Mg3Fe and Mg2Si. The die cast alloy 380 is rich in Cu and Fe elements. These alloying elements result in formation of the intermetallic phases Al 5FeSi, Al2Cu and Al(FeCuCr) along with primary-Si. The Cu- and Fe-rich IMPS are cathodic with respect to the matrix phase and strongly govern the corrosion behavior of the two cast alloys in an aggressive environment due to formation of local electrochemical cell in their vicinity. Results have shown that corrosion behavior of permanent mould cast alloy 356 is significantly better than the die cast aluminum alloy 380, primarily due to high content of Cu- and Fe-rich phases such as Al2Cu and Al 5FeSi in the latter. The IMPS also alter the protection mechanism of the cast alloys in the presence of inhibitors in an environment. The presence of chromate in the solution results in reduced cathodic activity on all the phases. Chromate provides some anodic inhibition by increasing pitting potentials and altering corrosion potentials for the phases. Results have shown that performance of CCC was much better on 356 than on 380, primarily due to inhomogeneous and incomplete coating deposition on Cu- and Fe- phases present in alloy 380. XPS and Raman were used to characterize coating deposition on intermetallics. Results show evidence of cyanide complex formation on the intermetallic phases. The presence of this complex is speculated to locally suppress CCC formation. Formation and breakdown of cerium conversion coatings on 356 and 380 was also analyzed. Results showed that deposition of cerium hydroxide started with heavy precipitation on intermetallic particles with the coatings growing outwards onto the matrix. Electrochemical analysis of synthesized intermetallics compounds in the

  8. Comparison of corrosion protection provided by a non-volatile organic compound epoxy and a marine epoxy primer

    SciTech Connect

    Kendig, M.W.; Ryang, H.S.; Liao, T.L.; Jeanjaquet, S.L.

    1999-03-01

    An epoxy resin formulation completely free of organic solvent was applied to carbon steel coupons using supercritical carbon dioxide (CO{sub 2}) as the volatile solvent. Steel coupons coated in this manner were compared to coupons coated with a standard military specification marine primer (MIL-P-24441) during exposure to aerated 0.5 M sodium chloride (NaCl). The solvent-free coating protected the steel from corrosion in this environment as well, if not better than, the solvent-based primer.

  9. Hazardous and Corrosive Gas Production in the Radiolysis of Water/Organic Mixtures in Model TRU Waste

    SciTech Connect

    LaVerne, Jay A.

    2005-06-01

    Experiments in combination with diffusion-kinetic modeling incorporating track structure simulations are used to examine the radiation chemistry of aqueous systems containing chlorinated hydrocarbons. Irradiations with both Co-60 gamma rays and alpha particles are employed in order to simulate typical mixed radiation environments encountered in waste management. The goal is to determine fundamental mechanisms, kinetics, and yields for the formation of potentially explosive gases and corrosive agents, such as H2 and HCl, respectively, in the radiolysis of water-organic mixtures. The radiation chemical systems studied are found throughout the DOE portfolio and are important in radioactive waste remediation and management.

  10. Microgalvanic Aspects of the Seawater Corrosion of Marine Materials in the Presence of Hypochlorite Ion Fouling Inhibitor.

    DTIC Science & Technology

    1979-12-01

    diagrams --------------------------------- 270-272 E-4-E-7 Pourbaix diagrams ------------------------------ 273-277 E-8 Experimentally measured corrosion...formation of copper(III). Pourbaix [49] has calculated a potential-pH diagram including the compounds copper(III) ion and CuO 2 - The simple experiment...Figure E-4. Pourbaix diagram for the system copper-water. (b) Cu(OH) 2 not considered. 274 -2 -1 0 1 -2_ 3 4 5 6 7 8 9 10 11 12 13 14 15 162, 1,4

  11. Role(s) of pretreatment, inhibitors, and other process steps that effect surface composition on the under-paint corrosion of an aluminum-copper-magnesium alloy 2024-T3

    NASA Astrophysics Data System (ADS)

    Little, Daryl A.

    2006-12-01

    Under-paint corrosion is a surface corrosion that grows under a coating. The composition of an aluminum alloy, particularly Cu and Fe content, has a direct and dominant effect on the growth rate of filiform corrosion (FFC) and scribe-creep. The Cu and Fe content leads to formation of galvanic cells between intermetallic compounds (IMCs) or replated Cu and the aluminum-rich matrix. However, there is no model which describes scribe-creep behavior and can be used to predict the effect of material and surface pretreatment parameters such as inhibitors, chemical surface pretreatment, and alloy microstructure. Surface pretreatments and aging which control the amount of surface copper and alter IMC distributions decrease the growth rate of scribe-creep. Scribe-creep was observed to be enhanced by temperature, regardless of surface pretreatment, as well as by artificial aging and surface pretreatments. Scribe-creep was accelerated by pretreatments that increased surface copper or left a high capacity for Cu-replating such as Cu-containing IMCs. Pretreatment was rationalized to decrease the cathodic oxygen reduction reaction (ORR) rate, which supports anodic undercutting at the head of the corrosion front. In this galvanic corrosion mechanism, the scribe-creep rate will be proportional to the rate of the anodic dissolution at the head. This, in turn, is proportional to the galvanic corrosion rate. Both charge transfer controlled and mass transport controlled cathodic reaction rates occurred at the fastest rates at the scratch and tail. The charge transfer controlled cathodic reaction rate was directly proportional to the surface coverage of Cu (thetaCu) while the mass transport limited rate was a complex nonlinear function of thetaCu . Based on enhanced understanding a galvanic couple model that describes scribe-creep rates in terms of the relevant processes at the tail and head as well as ohmic voltage between the head and tail was developed in order to explain scribe

  12. Metalloproteinase Inhibitors: Status and Scope from Marine Organisms

    PubMed Central

    Thomas, Noel Vinay; Kim, Se-Kwon

    2010-01-01

    Marine environment has been the source of diverse life forms that produce different biologically active compounds. Marine organisms are consistently contributing with unparalleled bioactive compounds that have profound applications in nutraceuticals, cosmeceuticals, and pharmaceuticals. In this process, screening of natural products from marine organisms that could potentially inhibit the expression of metalloproteinases has gained a huge popularity, which became a hot field of research in life sciences. Metalloproteinases, especially, matrix metalloproteinases (MMPs) are a class of structurally similar enzymes that contribute to the extracellular matrix degradation and play major role in normal and pathological tissue remodeling. Imbalance in the expression of MMPs leads to severe pathological condition that could initiate cardiac, cartilage, and cancer-related diseases. Three decades of endeavor for designing potent matrix metalloproteinase inhibitory substances (MMPIs) with many not making upto final clinical trials seek new resources for devising MMPIs. Umpteen number of medicinally valuable compounds being reported from marine organisms, which encourage current researchers to screen potent MMPIs from marine organisms. In this paper, we have made an attempt to report the metalloproteinase inhibiting substances from various marine organisms. PMID:21197102

  13. Metalloproteinase inhibitors: status and scope from marine organisms.

    PubMed

    Thomas, Noel Vinay; Kim, Se-Kwon

    2010-01-01

    Marine environment has been the source of diverse life forms that produce different biologically active compounds. Marine organisms are consistently contributing with unparalleled bioactive compounds that have profound applications in nutraceuticals, cosmeceuticals, and pharmaceuticals. In this process, screening of natural products from marine organisms that could potentially inhibit the expression of metalloproteinases has gained a huge popularity, which became a hot field of research in life sciences. Metalloproteinases, especially, matrix metalloproteinases (MMPs) are a class of structurally similar enzymes that contribute to the extracellular matrix degradation and play major role in normal and pathological tissue remodeling. Imbalance in the expression of MMPs leads to severe pathological condition that could initiate cardiac, cartilage, and cancer-related diseases. Three decades of endeavor for designing potent matrix metalloproteinase inhibitory substances (MMPIs) with many not making upto final clinical trials seek new resources for devising MMPIs. Umpteen number of medicinally valuable compounds being reported from marine organisms, which encourage current researchers to screen potent MMPIs from marine organisms. In this paper, we have made an attempt to report the metalloproteinase inhibiting substances from various marine organisms.

  14. Synthesis and evaluation of poly(Sodium 2-Acrylamido-2-Methylpropane Sulfonate-co-Styrene)/magnetite nanoparticle composites as corrosion inhibitors for steel.

    PubMed

    El-Mahdy, Gamal A; Atta, Ayman M; Al-Lohedan, Hamad A

    2014-01-30

    Self-stabilized magnetic polymeric composite nanoparticles of coated poly-(sodium 2-acrylamido-2-methylpropane sulfonate-co-styrene)/magnetite (PAMPS-Na-co-St/Fe3O4) were prepared by emulsifier-free miniemulsion polymerization using styrene (St) as a monomer, 2-acrylamido-2-methylpropane sulfonic acid sodium salt (AMPS-Na) as an ionic comonomer, N,N-methylenebisacrylamide (MBA) as crosslinker, hexadecane (HD) as a hydrophobic solvent, and 2,2-azodiisobutyronitrile (AIBN) as an initiator in the presence of hydrophobic oleic acid coated magnetite particles. Hydrophobic oleic acid coated magnetite particles with an average size of about 7-10 nm were prepared with the new modified water-based magnetite ferrofluid, synthesized by a chemical modified coprecipitation method. The morphology and the particle size distributions of the crosslinked PAMPS-Na-co-St/Fe3O4 composite were observed and analyzed by transmission electron microscopy (TEM). The average Fe3O4 content of PAMPS-Na-co-St/Fe3O4 was determined by thermogravimetric analysis (TGA). The inhibitory action of PAMPS-Na-co-St/Fe3O4 towards steel corrosion in 1 M HCl solutions has been investigated by polarization and electrochemical impedance spectroscopy (EIS) methods. Polarization measurements indicate that PAMPS-Na-co-St/Fe3O4 acts as a mixed type-inhibitor and the inhibition efficiency increases with inhibitor concentration. The results of potentiodynamic polarization and EIS measurements clearly showed that the inhibition mechanism involves blocking of the steel surface by inhibitor molecules via adsorption.

  15. Bench-scale evaluation of ferrous iron oxidation kinetics in drinking water: effect of corrosion control and dissolved organic matter.

    PubMed

    Rahman, Safiur; Gagnon, Graham A

    2014-01-01

    Corrosion control strategies are important for many utilities in maintaining water quality from the water treatment plant to the customers' tap. In drinking water with low alkalinity, water quality can become significantly degraded in iron-based pipes if water utilities are not diligent in maintaining proper corrosion control. This article reports on experiments conducted in bicarbonate buffered (5 mg-C/L) synthetic water to determine the effects of corrosion control (pH and phosphate) and dissolved organic matter (DOM) on the rate constants of the Fe(II) oxidation process. A factorial design approach elucidated that pH (P = 0.007, contribution: 42.5%) and phosphate (P = 0.025, contribution: 22.7%) were the statistically significant factors in the Fe(II) oxidation process at a 95% confidence level. The comprehensive study revealed a significant dependency relationship between the Fe(II) oxidation rate constants (k) and phosphate-to- Fe(II) mole ratio. At pH 6.5, the optimum mole ratio was found to be 0.3 to reduce the k values. Conversely, the k values were observed to increase for the phosphate-to- Fe(II) mole ratio > 1. The factorial design approach revealed that chlorine and DOM for the designated dosages did not cause a statistically significant (α = 0.05, P > 0.05)change in rate constants. However, an increment of the chlorine to ferrous iron mole ratio by a factor of ∼ 2.5 resulted in an increase k values by a factor of ∼ 10. This study conclusively demonstrated that the lowest Fe(II) oxidation rate constant was obtained under low pH conditions (pH ≤ 6.5), with chlorine doses less than 2.2 mg/L and with a phosphate-to-Fe(II) mole ratio ≈ 0.3 in the iron water systems.

  16. A Novel Schiff Base of 3-acetyl-4-hydroxy-6-methyl-(2H)pyran-2-one and 2,2'-(ethylenedioxy)diethylamine as Potential Corrosion Inhibitor for Mild Steel in Acidic Medium

    PubMed Central

    Asegbeloyin, Jonnie N.; Ejikeme, Paul M.; Olasunkanmi, Lukman O.; Adekunle, Abolanle S.; Ebenso, Eno E.

    2015-01-01

    The corrosion inhibition activity of a newly synthesized Schiff base (SB) from 3-acetyl-4-hydroxy-6-methyl-(2H)-pyran-2-one and 2,2'-(ethylenedioxy)diethylamine was investigated on the corrosion of mild steel in 1 M HCl solution using potentiodynamic polarization and electrochemical impedance spectroscopic techniques. Ultraviolet-visible (UV-vis) and Raman spectroscopic techniques were used to study the chemical interactions between SB and mild steel surface. SB was found to be a relatively good inhibitor of mild steel corrosion in 1 M HCl. The inhibition efficiency increases with increase in concentration of SB. The inhibition activity of SB was ascribed to its adsorption onto mild steel surface, through physisorption and chemisorption, and described by the Langmuir adsorption model. Quantum chemical calculations indicated the presence of atomic sites with potential nucleophilic and electrophilic characteristics with which SB can establish electronic interactions with the charged mild steel surface.

  17. Corrosion Mitigation Strategies - an Introduction

    DTIC Science & Technology

    2009-02-05

    Control Technology – Cathodic protection – Corrosion inhibitors – Combination of methods • Balance cost and other factors Candidate Materials - Metals...Technology -UV, ozone,solvents,oxygen • Concrete -acids, chlorides, sulfates • Vitreous Materials-solvents • Corrosion Control • Waterproofing • Weather...Tar Enamel Leaders in Corrosion Control Technology – Tape – Concrete (Weight) Coating • Make metal to be protected act as a cathode • Application of

  18. Smart Coatings for Corrosion Protection

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

    Nearly all metals and their alloys are subject to corrosion that causes them to lose their structural integrity or other critical functionality. It is essential to detect corrosion when it occurs, and preferably at its early stage, so that action can be taken to avoid structural damage or loss of function. Protective coatings are the most commonly used method of corrosion control. However, progressively stricter environmental regulations have resulted in the ban of many commercially available corrosion protective coatings due to the harmful effects of their solvents or corrosion inhibitors. This work concerns the development of a multifunctional, smart coating for the autonomous control of corrosion. This coating is being developed to have the inherent ability to detect the chemical changes associated with the onset of corrosion and respond autonomously to indicate it and control it.

  19. Fastener corrosion : testing, research, and design considerations

    Treesearch

    Douglas R. Rammer; Samuel L. Zelinka; Philip Line

    2006-01-01

    In 2004, the voluntary removal of chromated copper arsenate (CCA) from residential wood construction raised concern about corrosion of metal fasteners in wood treated with replacement preservatives. Replacement preservatives contain more copper, which may increase corrosion, and do not contain chromates or arsenates, which are known corrosion inhibitors. This paper is...

  20. The organic anion transport inhibitor probenecid increases brain concentrations of the NKCC1 inhibitor bumetanide.

    PubMed

    Töllner, Kathrin; Brandt, Claudia; Römermann, Kerstin; Löscher, Wolfgang

    2015-01-05

    Bumetanide is increasingly being used for experimental treatment of brain disorders, including neonatal seizures, epilepsy, and autism, because the neuronal Na-K-Cl cotransporter NKCC1, which is inhibited by bumetanide, is implicated in the pathophysiology of such disorders. However, use of bumetanide for treatment of brain disorders is associated with problems, including poor brain penetration and systemic adverse effects such as diuresis, hypokalemic alkalosis, and hearing loss. The poor brain penetration is thought to be related to its high ionization rate and plasma protein binding, which restrict brain entry by passive diffusion, but more recently brain efflux transporters have been involved, too. Multidrug resistance protein 4 (MRP4), organic anion transporter 3 (OAT3) and organic anion transporting polypeptide 2 (OATP2) were suggested to mediate bumetanide brain efflux, but direct proof is lacking. Because MRP4, OAT3, and OATP2 can be inhibited by probenecid, we studied whether this drug alters brain levels of bumetanide in mice. Probenecid (50 mg/kg) significantly increased brain levels of bumetanide up to 3-fold; however, it also increased its plasma levels, so that the brain:plasma ratio (~0.015-0.02) was not altered. Probenecid markedly increased the plasma half-life of bumetanide, indicating reduced elimination of bumetanide most likely by inhibition of OAT-mediated transport of bumetanide in the kidney. However, the diuretic activity of bumetanide was not reduced by probenecid. In conclusion, our study demonstrates that the clinically available drug probenecid can be used to increase brain levels of bumetanide and decrease its elimination, which could have therapeutic potential in the treatment of brain disorders.

  1. Corrosion protection of equipment in recirculating water supply systems

    SciTech Connect

    Teslya, B.M.; Burlov, V.V.; Shadrina, A.N.; Vyazhevich, A.V.

    1983-01-01

    The metals in the condensers, coolers and heat exchangers of petroleum refineries and petrochemical plants are subject to corrosion, and this is responsible for forced shutdowns. This paper notes that the shortest service life is given by the carbon and silicon-manganese steels, the longest by the chrome-nickel steels and arsenic-alloyed brasses. It reports that a high level of protection is provided by the use of the inhibitor IKB-4V at the Industrial Association ''Novopolotsknefteorgsintez'' and a so-called complex corrosion retarder consisting of a mixture of zinc sulfate and orthophosphoric acid at the Novo-Ufa refinery. It also points out that the most desirable method for corrosion protection of cooling towers, from the standpoint of technical and economic justification, is the use of protective paint coatings. It urges scientific research and design organizations and also the plants of the petroleum refining and petrochemical industry to take a multipronged approach in solving problems in corrosion control. It is pointed out that protection by inhibitors must be combined with the use of paints and other types of organic and inorganic coatings, protection against salt deposition and biological overgrowth, and the rational use of corrosion-resistant materials of construction.

  2. Evaluation of Thymus vulgaris plant extract as an eco-friendly corrosion inhibitor for stainless steel 304 in acidic solution by means of electrochemical impedance spectroscopy, electrochemical noise analysis and density functional theory.

    PubMed

    Ehsani, A; Mahjani, M G; Hosseini, M; Safari, R; Moshrefi, R; Mohammad Shiri, H

    2017-03-15

    Inhibition performance of Thymus vulgaris plant leaves extract (thyme) as environmentally friendly (green) inhibitor for the corrosion protection of stainless steel (SS) type 304 in 1.0molL(-1) HCl solution was studied by potentiodynamic polarization, electrochemical impedance (EIS) and electrochemical noise measurements (EN) techniques. The EN data were analyzed with FFT technique to make the spectral power density plots. The calculations were performed by MATLAB 2014a software. Geometry optimization and calculation of the structural and electronic properties of the molecular system of inhibitor have been carried out using UB3LYP/6-311++G(∗∗) level. Moreover, the results obtained from electrochemical noise analysis were compared with potentiodynamic polarization and electrochemical impedance spectroscopy. All of the used techniques showed positive effect of green inhibitor with increasing inhibitor concentration.

  3. Metalloprotease Peptide Inhibitors: A Semester-Long Organic Synthetic Research Project for the Introductory Laboratory Course

    ERIC Educational Resources Information Center

    Pontrello, Jason K.

    2015-01-01

    A semester-long research project to synthesize unique compounds designed after published metalloprotease peptide inhibitors is presented. The research project encompasses a set of nine organic chemistry reactions traditionally taught in the second semester lab course, and the procedures are derived from scientific literature. The two principle…

  4. Metalloprotease Peptide Inhibitors: A Semester-Long Organic Synthetic Research Project for the Introductory Laboratory Course

    ERIC Educational Resources Information Center

    Pontrello, Jason K.

    2015-01-01

    A semester-long research project to synthesize unique compounds designed after published metalloprotease peptide inhibitors is presented. The research project encompasses a set of nine organic chemistry reactions traditionally taught in the second semester lab course, and the procedures are derived from scientific literature. The two principle…

  5. Development of inorganic and organic hybrid nanocoating based on carbon nanotubes for corrosion resistance.

    PubMed

    Kang, T H; Bagkar, Nitin C; Jung, Y S; Chun, H H; Shin, S C; Cho, H; Kim, J K; Kim, T G

    2014-10-01

    In this study, we report the synthesis and characterization of novel hybrid nanocoating based on carbon nanotubes (CNTs) on anodized aluminum surfaces (AAO). The hybrid nanocoating was deposited by number of methods which include spray coating, spin coating and dip coating. The bonding of nanocoating with metal surface is an important parameter for successful modification of the metal surfaces. The improved adhesion of nanocoating on metal surfaces could be attributed to chemical bonding of sol-gel nanocoating with anodized surfaces. The nanocoated anodized aluminum surfaces showed superior adhesion and excellent anticorrosive properties. The nanocoated panels showed enhanced galvanic protection comparable to 80% of titanium metal as determined by galvanic corrosion measurements. It also showed higher thermal conductivities than stainless steel and bare anodized surfaces.

  6. Corrosion cracking

    SciTech Connect

    Goel, V.S.

    1985-01-01

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

  7. Galvanic corrosion of Cu coupled to Au on a print circuit board; Effects of pretreatment solution and etchant concentration in organic solderability preservatives soft etching solution

    NASA Astrophysics Data System (ADS)

    Oh, SeKwon; Kim, YoungJun; Shon, MinYoung; Kwon, HyukSang

    2016-09-01

    In present study, we quantitatively define the galvanic corrosion phenomenon of Cu electrically coupled to Au on Print Circuit Board in Organic Solderability Preservatives (OSP) pretreatment (pickling and soft etching) solutions. As a result of polarization and ZRA test, galvanic corrosion rate of Cu in soft etching solution was about 3000 times higher than that of pickling solution. The oxone in OSP soft etching solution was acted as strong oxidant for Cu on PCB substrate. And the galvanic corrosion of Cu in OSP soft etching solution was examined with the change of etchants (oxone (KHSO5), sulfuric acid (H2SO4)) concentration. The galvanic corrosion rate of Cu was increased by the increase of the oxone and sulfuric acid concentrations, which lead to the increase of cathodic reactant such as HSO 5 - and H+ ions. And the degree of galvanic corrosion rate of Cu (Δisoft etching = icouple, (Cu-Au) - icorr, Cu) decreased with the decrease of the oxone and sulfuric acid concentrations.

  8. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    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.

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

    NASA Astrophysics Data System (ADS)

    Bavarian, Behzad; Zhang, Jia; Reiner, Lisa

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

  10. pH Responsive Microcapsules for Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Li, Wenyan; Muehlberg, Aaron; Boraas, Samuel; Webster, Dean; JohnstonGelling, Victoria; Croll, Stuart; Taylor, S Ray; Contu, Francesco

    2008-01-01

    The best coatings for corrosion protection provide not only barriers to the environment, but also a controlled release of a corrosion inhibitor, as demanded by the presence of corrosion or mechanical damage. NASA has developed pH sensitive microcapsules (patent pending) that can release their core contents when corrosion starts. The objectives of the research presented here were to encapsulate non-toxic corrosion inhibitors, to incorporate the encapsulated inhibitors into paint formulations, and to test the ability of the paints to control corrosion. Results showed that the encapsulated corrosion inhibitors, specifically Ce(NO3)3 , are effective to control corrosion over long periods of time when incorporated at relatively high pigment volume concentrations into a paint formulation.

  11. Dysregulation of Protease and Protease Inhibitors in a Mouse Model of Human Pelvic Organ Prolapse

    PubMed Central

    Budatha, Madhusudhan; Silva, Simone; Montoya, Teodoro Ignacio; Suzuki, Ayako; Shah-Simpson, Sheena; Wieslander, Cecilia Karin; Yanagisawa, Masashi; Word, Ruth Ann; Yanagisawa, Hiromi

    2013-01-01

    Mice deficient for the fibulin-5 gene (Fbln5−/−) develop pelvic organ prolapse (POP) due to compromised elastic fibers and upregulation of matrix metalloprotease (MMP)-9. Here, we used casein zymography, inhibitor profiling, affinity pull-down, and mass spectrometry to discover additional protease upregulated in the vaginal wall of Fbln5−/− mice, herein named V1 (25 kDa). V1 was a serine protease with trypsin-like activity similar to protease, serine (PRSS) 3, a major extrapancreatic trypsinogen, was optimum at pH 8.0, and predominantly detected in estrogenized vaginal epithelium of Fbln5−/− mice. PRSS3 was (a) localized in epithelial secretions, (b) detected in media of vaginal organ culture from both Fbln5−/− and wild type mice, and (c) cleaved fibulin-5 in vitro. Expression of two serine protease inhibitors [Serpina1a (α1-antitrypsin) and Elafin] was dysregulated in Fbln5−/− epithelium. Finally, we confirmed that PRSS3 was expressed in human vaginal epithelium and that SERPINA1 and Elafin were downregulated in vaginal tissues from women with POP. These data collectively suggest that the balance between proteases and their inhibitors contributes to support of the pelvic organs in humans and mice. PMID:23437119

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

    SciTech Connect

    1998-12-31

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

  13. Antidiabetic, Chemical, and Physical Properties of Organic Vanadates as Presumed Transition-State Inhibitors for Phosphatases.

    PubMed

    Crans, Debbie C

    2015-12-18

    Studies of antidiabetic vanadium compounds, specifically the organic vanadate esters, are reviewed with regard to their chemistry and biological properties. The compounds are described from the perspective of how the fundamental chemistry and properties of organic vanadate esters impact their effects as inhibitors for phosphatases based on the structural information obtained from vanadium-phosphatase complexes. Vanadium compounds have been reported to have antidiabetic properties for more than a century. The structures and properties of organic vanadate complexes are reviewed, and the potency of such vanadium coordination complexes as antidiabetic agents is described. Because such compounds form spontaneously in aqueous environments, the reactions with most components in any assay or cellular environment has potential to be important and should be considered. Generally, the active form of vanadium remains elusive, although studies have been reported of a number of promising vanadium compounds. The description of the antidiabetic properties of vanadium compounds is described here in the context of recent characterization of vanadate-phosphatase protein structures by data mining. Organic vanadate ester compounds are generally four coordinate or five coordinate with the former being substrate analogues and the latter being transition-state analogue inhibitors. These studies demonstrated a framework for characterization of five-coordinate trigonal bipyramidal vanadium inhibitors by comparison with the reported vanadium-protein phosphatase complexes. The binding of the vanadium to the phosphatases is either as a five-coordinate exploded transition-state analogue or as a high energy intermediate, respectively. Even if potency as an inhibitor requires trigonal bipyramidal geometry of the vanadium when bound to the protein, such geometry can be achieved upon binding from compounds with other geometries. Desirable properties of ligands are identified and analyzed. Ligand

  14. Immunosuppressive potency of mechanistic target of rapamycin inhibitors in solid-organ transplantation

    PubMed Central

    Baroja-Mazo, Alberto; Revilla-Nuin, Beatriz; Ramírez, Pablo; Pons, José A

    2016-01-01

    Mammalian target of rapamycin, also known as mechanistic target of rapamycin (mTOR) is a protein kinase that belongs to the PI3K/AKT/mTOR signaling pathway, which is involved in several fundamental cellular functions such as cell growth, proliferation, and survival. This protein and its associated pathway have been implicated in cancer development and the regulation of immune responses, including the rejection response generated following allograft transplantation. Inhibitors of mTOR (mTORi) such as rapamycin and its derivative everolimus are potent immunosuppressive drugs that both maintain similar rates of efficacy and could optimize the renal function and diminish the side effects compared with calcineurin inhibitors. These drugs are used in solid-organ transplantationtoinduceimmunosuppression while also promoting the expansion of CD4+CD25+FOXP3+ regulatory T-cells that could favor a scenery of immunological tolerance. In this review, we describe the mechanisms by which inhibitors of mTOR induce suppression by regulation of these pathways at different levels of the immune response. In addition, we particularly emphasize about the main methods that are used to assess the potency of immunosuppressive drugs, highlighting the studies carried out about immunosuppressive potency of inhibitors of mTOR. PMID:27011916

  15. Hybrid organic-inorganic network coatings for protecting metal substrates from abrasion and corrosion

    SciTech Connect

    Jordens, K.; Wilkes, G.

    1996-12-31

    Ceramers or Ormocers are hybrid organic-inorganic materials first created a decade ago, and are the subject of a recent review article. Recent research from the authors laboratory in this area of materials science has focused on synthesizing protective coatings for (soft) polymeric substrates, i.e. polycarbonate. The authors have now extended the application of such coatings to metallic substrates.

  16. Undoped Polyaniline/Surfactant Complex for the Corrosion Prevention

    NASA Technical Reports Server (NTRS)

    Liu, Lo-Min; Levon, Kalle

    1998-01-01

    Due to the strict regulations on the usage of heavy metals as the additives in the coating industries, the search for effective organic corrosion inhibitors in replace of those metal additives has become essential. Electrically conducting polymers have been shown to be effective for corrosion prevention but the poor solubility of these intractable polymers has been a problem. We have explored a polyaniline/4-dodecylphenol complex (PANi/DDPh) to improve the dissolution and it has been shown to be an effective organic corrosion inhibitor. With the surfactant, DDPh, PANi could be diluted into the coatings and the properties of the coatings were affected. Emeraldine base (EB) form of PANi was also found to be oxidized by the hardener. The oxidized form of polyaniline provides improved corrosion protection of metals than that of emeraldine base since the value of the standard electrode potential for the oxidized form of PANi is higher than that of EB. Additionally, the surfactant improves the wet adhesion property between the coating and the metal surface.

  17. The Use of Organic Humectants as Non-Corrosive Dust Control Agents

    DTIC Science & Technology

    2010-02-01

    Aldonic Acids • Aldonic acids, lactobionic acid and maltobionic acid can be chemically modified to form surfactants that bond more firmly to soil...Mixtures of hydrogel and surfactants moieties may be best for capturing and holding dust particles Comparison of Water Retention for Organic... cosmetics and pharmaceuticals • Gel matrix film contains approximately 14% water • Does not irritate or harm exposed skin. • Can prevent air entrainment of dust without harming plants.

  18. Corrosion Control through a Better Understanding of the Metallic Substrate/Organic Coating/Interface.

    DTIC Science & Technology

    1984-12-13

    program. These activities are concerned with (a) the chemical nature of the oxide on the surface of steel; (b) the loss of adhesion of an organic...protective coatings for the purpose of promoting adhesion . Methanol is a very efficient hydrophobing agent for a-Fe 203 when the oxide is previously...dissolution of material in the interfacial region or attack of the polymer with a consequent loss in adhesion of the coating. Three studies are being

  19. Combinatorial pharmacophore modeling of organic cation transporter 2 (OCT2) inhibitors: insights into multiple inhibitory mechanisms.

    PubMed

    Xu, Yuan; Liu, Xian; Li, Shanshan; Zhou, Nannan; Gong, Likun; Luo, Cheng; Luo, Xiaomin; Zheng, Mingyue; Jiang, Hualiang; Chen, Kaixian

    2013-12-02

    Organic cation transporter 2 (OCT2) is responsible for the entry step of many drugs in renal elimination, of which the changing activity may cause unwanted drug-drug interactions (DDIs). To develop drugs with favorable safety profile and provide instruction for rational clinical drug administration, it is of great interest to investigate the multiple mechanisms of OCT2 inhibition. In this study, we designed a combinatorial scheme to screen the optimum combination of pharmacophores from a pool of hypotheses established based on 162 OCT2 inhibitors. Among them, one single pharmacophore hypothesis represents a potential binding mode that may account for one unique inhibitory mechanism, and the obtained pharmacophore combination describes the multimechanisms of OCT2 inhibition. The final model consists of four individual pharmacophores, i.e., DHPR18, APR2, PRR5 and HHR4. Given a query ligand, it is considered as an inhibitor if it matches at least one of the hypotheses, or a noninhibitor if it fails to match any of four hypotheses. Our combinatorial pharmacophore model performs reasonably well to discriminate inhibitors and noninhibitors, yielding an overall accuracy around 0.70 for a test set containing 81 OCT2 inhibitors and 218 noninhibitors. Intriguingly, we found that the number of matched hypotheses was positively correlated with inhibition rate, which coincides with the pharmacophore modeling result of P-gp substrate binding. Further analysis suggested that the hypothesis PRR5 was responsible for competitive inhibition of OCT2, and other hypotheses were important for interaction between the inhibitor and OCT2. In light of the results, a hypothetical model for inhibiting transporting mediated by OCT2 was proposed.

  20. Proton Pump Inhibitors Inhibit Metformin Uptake by Organic Cation Transporters (OCTs)

    PubMed Central

    Nies, Anne T.; Hofmann, Ute; Resch, Claudia; Schaeffeler, Elke; Rius, Maria; Schwab, Matthias

    2011-01-01

    Metformin, an oral insulin-sensitizing drug, is actively transported into cells by organic cation transporters (OCT) 1, 2, and 3 (encoded by SLC22A1, SLC22A2, or SLC22A3), which are tissue specifically expressed at significant levels in various organs such as liver, muscle, and kidney. Because metformin does not undergo hepatic metabolism, drug-drug interaction by inhibition of OCT transporters may be important. So far, comprehensive data on the interaction of proton pump inhibitors (PPIs) with OCTs are missing although PPIs are frequently used in metformin-treated patients. Using in silico modeling and computational analyses, we derived pharmacophore models indicating that PPIs (i.e. omeprazole, pantoprazole, lansoprazole, rabeprazole, and tenatoprazole) are potent OCT inhibitors. We then established stably transfected cell lines expressing the human uptake transporters OCT1, OCT2, or OCT3 and tested whether these PPIs inhibit OCT-mediated metformin uptake in vitro. All tested PPIs significantly inhibited metformin uptake by OCT1, OCT2, and OCT3 in a concentration-dependent manner. Half-maximal inhibitory concentration values (IC50) were in the low micromolar range (3–36 µM) and thereby in the range of IC50 values of other potent OCT drug inhibitors. Finally, we tested whether the PPIs are also transported by OCTs, but did not identify PPIs as OCT substrates. In conclusion, PPIs are potent inhibitors of the OCT-mediated metformin transport in vitro. Further studies are needed to elucidate the clinical relevance of this drug-drug interaction with potential consequences on metformin disposition and/or efficacy. PMID:21779389

  1. Synthesis and characterization of an effective organic/inorganic hybrid green corrosion inhibitive complex based on zinc acetate/Urtica Dioica

    NASA Astrophysics Data System (ADS)

    Salehi, E.; Naderi, Reza; Ramezanzadeh, B.

    2017-02-01

    This study aims at synthesis and characterization of an effective corrosion inhibitive complex based on zinc acetate/Urtica Dioica (ZnA-U.D) for corrosion protection of mild steel in chloride solution. The chemical structure and morphology of the complex were characterized by Fourier transform infrared spectroscopy (FT-IR), UV-vis, thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The corrosion protection performance of the mild steel samples dipped in 3.5 wt.% NaCl solutions with and without ZnA-U.D extract was investigated by visual observations, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS) and polarization test. Results revealed that the ZnA successfully chelated with organic inhibitive compounds (i.e Quercetin, Quinic acid, Caffeic acid, Hystamine and Serotonin) present in the U.D extract. The electrochemical measurements revealed the effective inhibition action of ZnA-U.D complex in the sodium chloride solution on the mild steel. The synergistic effect between Zn2+ and organic compounds present in the U.D extract resulted in protective film deposition on the steel surface, which was proved by SEM and XPS analyses.

  2. Global feedback control of Turing patterns in network-organized activator-inhibitor systems

    NASA Astrophysics Data System (ADS)

    Hata, S.; Nakao, H.; Mikhailov, A. S.

    2012-06-01

    Results of the first systematic study on feedback control of nonequilibrium pattern formation in networks are reported. Effects of global feedback control on Turing patterns in network-organized activator-inhibitor system have been investigated. The feedback signal was introduced into one of the parameters of the system and was proportional to the amplitude of the developing Turing pattern. Without the control, the Turing instability corresponded to a subcritical bifurcation and hysteresis effects were observed. Sufficiently strong feedback control rendered, however, the bifurcation supercritical and eliminated the hysteresis effects.

  3. Recent Developments on Autonomous Corrosion Protection Through Encapsulation

    NASA Technical Reports Server (NTRS)

    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. Controlled-Release Microcapsules for Smart Coatings for Corrosion Applications

    NASA Technical Reports Server (NTRS)

    2008-01-01

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

  5. Effect of calpain inhibitor I, an inhibitor of the proteolysis of IκB, on the circulatory failure and multiple organ dysfunction caused by endotoxin in the rat

    PubMed Central

    Ruetten, Hartmut; Thiemermann, Christoph

    1997-01-01

    We compared the effects of calpain inhibitor I (inhibitor of the proteolysis of IκB and, hence, of the activation of nuclear factor κB (NFκB)) and dexamethasone on (i) the circulatory failure, (ii) multiple organ dysfunction and (iii) induction of the inducible isoforms of nitric oxide (NO) synthase (iNOS) and cyclo-oxygenase (COX-2) in anaesthetized rats with endotoxic shock. Injection of lipopolysaccharide (LPS, E. coli, 10 mg kg−1, i.v.) resulted in hypotension and a reduction of the pressor responses elicited by noradrenaline. This circulatory dysfunction was attenuated by pretreatment of LPS-rats with calpain inhibitor I (10 mg kg−1, i.v., 2 h before LPS) or dexamethasone (1 mg kg−1, i.v.). Endotoxaemia also caused rises in the serum levels of (i) urea and creatinine (renal dysfunction), (ii) alanine aminotransferase (ALT), aspartate aminotransferase (AST) (hepatocellular injury), bilirubin and γ-glutamyl transferase (γGT) (liver dysfunction), (iii) lipase (pancreatic injury) and (iv) lactate. Calpain inhibitor I and dexamethasone attenuated the liver injury, the pancreatic injury, the lactic acidosis as well as the hypoglycaemia caused by LPS. Dexamethasone, but not calpain inhibitor I, reduced the renal dysfunction caused by LPS. Endotoxaemia for 6 h resulted in a substantial increase in iNOS and COX-2 protein and activity in lung and liver, which was attenuated in LPS-rats pretreated with calpain inhibitor I or dexamethasone. Thus, calpain inhibitor I and dexamethasone attenuate (i) the circulatory failure, (ii) the multiple organ dysfunction (liver and pancreatic dysfunction/injury, lactic acidosis, hypoglycaemia), as well as (iii) the induction of iNOS and COX-2 protein and activity in rats with endotoxic shock. We propose that prevention of the activation of NF-κB in vivo may be useful in the therapy of circulatory shock or of disorders associated with local or systemic inflammation. PMID:9208136

  6. Inhibitor analysis for a solar heating and cooling system

    NASA Technical Reports Server (NTRS)

    Tabony, J. H.

    1977-01-01

    A study of potential corrosion inhibitors for the NASA solar heating and cooling system which uses aluminum solar panels is provided. Research consisted of testing using a dynamic corrosion system, along with an economic analysis of proposed corrosion inhibitors. Very good progress was made in finding a suitable inhibitor for the system.

  7. Corrosion protection

    DOEpatents

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

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

  8. Aircraft Corrosion

    DTIC Science & Technology

    1981-08-01

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

  9. [Microbial corrosion of dental alloy].

    PubMed

    Li, Lele; Liu, Li

    2004-10-01

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

  10. Zirconium for superior corrosion resistance

    SciTech Connect

    Bird, K.W.; Richardson, K.

    1997-03-01

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

  11. Corrosion Control in the Aerospace Industry

    NASA Technical Reports Server (NTRS)

    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..

  12. Corrosivity Of Pyrolysis Oils

    SciTech Connect

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

    2011-01-01

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

  13. Corrosion of copper in oxygen-deficient groundwater with and without deep bedrock micro-organisms: Characterisation of microbial communities and surface processes

    NASA Astrophysics Data System (ADS)

    Huttunen-Saarivirta, E.; Rajala, P.; Bomberg, M.; Carpén, L.

    2017-02-01

    Copper specimens were exposed to oxygen-deficient artificial groundwater in the presence and absence of micro-organisms enriched from the deep bedrock of the planned nuclear waste repository site at Olkiluoto island on the western coast of Finland. During the exposure periods of 4 and 10 months, the copper specimens were subjected to electrochemical measurements. The biofilm developed on the specimens and the water used in the exposures were subjected to microbiological analyses. Changes in the water chemistry were also determined and surfaces of the copper specimens were characterized with respect to the morphology and composition of the formed corrosion products. The results showed that under biotic conditions, redox of the water and open circuit potential (OCP) of the copper specimens were generally negative and resulted in the build-up of a copper sulphide, Cu2S, layer due to the activity of sulphate-reducing bacteria (SRB) that were included in the system. In the 4-month test, the electrochemical behaviour of the specimens changed during the exposure and alphaproteobactria Rhizobiales were the dominant bacterial group in the biofilm where the highest corrosion rate was observed. In the 10-month test, however, deltaproteobacteria SRB flourished and the initial electrochemical behaviour and the low corrosion rate of the copper were retained until the end of the test period. Under abiotic conditions, the positive water redox potential and specimen OCP correlated with the formation of copper oxide, Cu2O. Furthermore, in the absence of SRB, Cu2O provided slightly inferior protection against corrosion compared to that by Cu2S in the presence of SRB. The obtained results show that the presence of microorganisms may enhance the passivity of copper. In addition, the identification of key microbial species, such as SRB thriving on copper for long time periods, is important for successful prediction of the behaviour of copper.

  14. Corrosion Engineering.

    ERIC Educational Resources Information Center

    White, Charles V.

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

  15. Fireside Corrosion

    SciTech Connect

    Holcomb, Gordon

    2011-07-14

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

  16. Non-melanoma skin cancer is reduced after switch of immunosuppression to mTOR-inhibitors in organ transplant recipients.

    PubMed

    Alter, Mareike; Satzger, Imke; Schrem, Harald; Kaltenborn, Alexander; Kapp, Alexander; Gutzmer, Ralf

    2014-06-01

    Organ transplant recipients are prone to the development of non-melanoma skin cancer. Organ transplant recipients often develop multiple non-melanoma skin cancers and the tumors show an aggressive growth pattern, therefore surgical therapy can be difficult. Switch of the immunosuppressive regimen to mTOR-inhibitors such as everolimus or sirolimus can have an antitumor effect. In a monocentric retrospective study we evaluated organ transplant recipients who presented with non-melanoma skin cancer in the years 2008-2010. Experience with patients who were switched to an mTOR-inhibitor due to non-melanoma skin cancer are reported in detail, and recent clinical studies are reviewed. 60 organ transplant recipients with non-melanoma skin cancer were evaluated. Due to the development of multiple non-melanoma skin cancer within a few years, the immunosuppressive regimen was switched to everolimus in 7 patients and to sirolimus in 5 patients. Eight patients were evaluable for the effect of mTOR-inhibitors on the development of non-melanoma skin cancer; 4 patients had to discontinue the medication with mTOR-inhibitors early due to various side effects. In the year before the switch to mTOR-inhibitors, 8 patients developed 16 squamous cell carcinomas, 3 Basal cell carcinomas and 22 cases of Bowen's disease. All tumors were histologically confirmed. In the year after switch of immunosuppression, the rate of squamous cell carcinomas (n = 2) and Bowen's disease (n = 3), but not of basal cell carcinomas (n = 2) was significantly reduced. Moreover, 5 prospective randomized trials recently have demonstrated a reduced number of non-melanoma skin cancers in organ transplant recipients after switch of the immunosuppressive regimen to mTOR-inhibitors. Switch of the immunosuppressive regimen to mTOR-inhibitors should be considered for organ transplant recipients suffering from multiple non-melanoma skin cancers. © 2014 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley

  17. Metalworking corrosion inhibition/drawing lubricant

    SciTech Connect

    Lipinski, H.F.; Wantling, S.J.

    1980-05-06

    A metalworking lubricant composition is disclosed which is effective as both a corrosion inhibitor and drawing lubricant and comprises a mineral oil and an additive combination of barium lanolate soap and barium sulfonate.

  18. Corrosion sensor

    DOEpatents

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

    1994-04-26

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

  19. Corrosion sensor

    DOEpatents

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

    1994-01-01

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

  20. Application of electrochemical methods in corrosion and battery research

    NASA Astrophysics Data System (ADS)

    Sun, Zhaoli

    Various electrochemical methods have been applied in the development of corrosion protection methods for ammonia/water absorption heat pumps and the evaluation of the stability of metallic materials in Li-ion battery electrolyte. Rare earth metal salts (REMSs) and organic inhibitors have been evaluated for corrosion protection of mild steel in the baseline solution of 5 wt% NH 3 + 0.2 wt% NaOH to replace the conventionally used toxic chromate salt inhibitors. Cerium nitrate provided at least comparable corrosion inhibition efficiency as dichromate in the baseline solution at 100°C. The cerium (IV) oxide formed on mild steel through the cerating process exhibited increasing corrosion protection for mild steel with prolonged exposure time in the hot baseline solution. The optimum cerating process was found to be first cerating in a solution of 2.3 g/L CeCl3 + 4.4 wt% H2O2 + appropriate additives for 20 minutes at pH 2.2 at room temperature with 30 minutes solution aging prior to use, then sealing in 10% sodium (meta) silicate or sodium molybdate at 50°C for 30 minutes. Yttrium salts provided less corrosion protection for mild steel in the baseline solution than cerium salts. Glycerophosphate was found to be a promising chromate-free organic inhibitor for mild steel; however, its thermostability in hot ammonia/water solutions has not been confirmed yet. The stability of six metallic materials used in Li-ion batteries has been evaluated in 1M lithium hexafluorophosphate (LiPF6) dissolved in a 1:1 volume mixture of ethylene carbonate and diethyl carbonate at 37°C in a dry-box. Aluminum is the most stable material, while Copper is active under anodic potentials and susceptible to localized corrosion and galvanic corrosion. The higher the concentration of the alloying elements Al and/or V in a titanium alloy, the higher was the stability of the titanium alloy in the battery electrolyte. 90Pt-10Ir can cause decomposition of the electrolyte resulting in a low stable

  1. Flavonoids are inhibitors of human organic anion transporter 1 (OAT1)-mediated transport.

    PubMed

    An, Guohua; Wang, Xiaodong; Morris, Marilyn E

    2014-09-01

    Organic anion transporter 1 (OAT1) has been reported to be involved in the nephrotoxicity of many anionic xenobiotics. As current clinically used OAT1 inhibitors are often associated with safety issues, identifying potent OAT1 inhibitors with little toxicity is of great value in reducing OAT1-mediated drug nephrotoxicity. Flavonoids are a class of polyphenolic compounds with exceptional safety records. Our objective was to evaluate the effects of 18 naturally occurring flavonoids, and some of their glycosides, on the uptake of para-aminohippuric acid (PAH) in both OAT1-expressing and OAT1-negative LLC-PK1 cells. Most flavonoid aglycones produced substantial decreases in PAH uptake in OAT1-expressing cells. Among the flavonoids screened, fisetin, luteolin, morin, and quercetin exhibited the strongest effect and produced complete inhibition of OAT1-mediated PAH uptake at a concentration of 50 μM. Further concentration-dependent studies revealed that both morin and luteolin are potent OAT1 inhibitors, with IC50 values of <0.3 and 0.47 μM, respectively. In contrast to the tested flavonoid aglycones, all flavonoid glycosides had negligible or small effects on OAT1. In addition, the role of OAT1 in the uptake of fisetin, luteolin, morin, and quercetin was investigated and fisetin was found to be a substrate of OAT1. Taken together, our results indicate that flavonoids are a novel class of OAT1 modulators. Considering the high consumption of flavonoids in the diet and in herbal products, OAT1-mediated flavonoid-drug interactions may be clinically relevant. Further investigation is warranted to evaluate the nephroprotective role of flavonoids in relation to drug-induced nephrotoxicity mediated by the OAT1 pathway.

  2. Flavonoids Are Inhibitors of Human Organic Anion Transporter 1 (OAT1)–Mediated Transport

    PubMed Central

    An, Guohua; Wang, Xiaodong

    2014-01-01

    Organic anion transporter 1 (OAT1) has been reported to be involved in the nephrotoxicity of many anionic xenobiotics. As current clinically used OAT1 inhibitors are often associated with safety issues, identifying potent OAT1 inhibitors with little toxicity is of great value in reducing OAT1-mediated drug nephrotoxicity. Flavonoids are a class of polyphenolic compounds with exceptional safety records. Our objective was to evaluate the effects of 18 naturally occurring flavonoids, and some of their glycosides, on the uptake of para-aminohippuric acid (PAH) in both OAT1-expressing and OAT1-negative LLC-PK1 cells. Most flavonoid aglycones produced substantial decreases in PAH uptake in OAT1-expressing cells. Among the flavonoids screened, fisetin, luteolin, morin, and quercetin exhibited the strongest effect and produced complete inhibition of OAT1-mediated PAH uptake at a concentration of 50 μM. Further concentration-dependent studies revealed that both morin and luteolin are potent OAT1 inhibitors, with IC50 values of <0.3 and 0.47 μM, respectively. In contrast to the tested flavonoid aglycones, all flavonoid glycosides had negligible or small effects on OAT1. In addition, the role of OAT1 in the uptake of fisetin, luteolin, morin, and quercetin was investigated and fisetin was found to be a substrate of OAT1. Taken together, our results indicate that flavonoids are a novel class of OAT1 modulators. Considering the high consumption of flavonoids in the diet and in herbal products, OAT1-mediated flavonoid-drug interactions may be clinically relevant. Further investigation is warranted to evaluate the nephroprotective role of flavonoids in relation to drug-induced nephrotoxicity mediated by the OAT1 pathway. PMID:25002746

  3. Selected phytotoxins and organic extracts from endophytic fungus Edenia gomezpompae as light reaction of photosynthesis inhibitors.

    PubMed

    Macías-Rubalcava, Martha Lydia; Ruiz-Velasco Sobrino, María Emma; Meléndez-González, Claudio; King-Díaz, Beatriz; Lotina-Hennsen, Blas

    2014-09-05

    In a search for natural herbicides, we investigated the action mechanism of the naphthoquinone spiroketals, isolated from the endophytic fungus Edenia gomezpompae: preussomerins EG1 (1) and EG4 (2), and palmarumycins CP17 (3), and CP2 (4) on the photosynthesis light reactions. The naphthoquinone spiroketals 1-4 inhibited the ATP synthesis in freshly lysed spinach thylakoids from water to MV, and they also inhibited the non-cyclic electron transport in the basal, phosphorylating and uncoupled conditions from water to MV. Therefore, they act as Hill reaction inhibitors. The results suggested that naphthoquinone spiroketals 1-4 have two interactions and inhibition site on the PSII electron transport chain. The first one involves the water splitting enzyme inhibition; and, the second on the acceptor site of PSII in a similar way that herbicide Diuron, studied by polaroghaphy and corroborated by fluorescence of the chlorophyll a of PSII. The culture medium and mycelium organic extracts from four morphological variants of E. gomezpompae were phytotoxic, and the culture medium extracts were more potent than mycelium extracts. They also act as Hill reaction inhibitors.

  4. Chloroquine and Hydroxychloroquine Are Novel Inhibitors of Human Organic Anion Transporting Polypeptide 1A2.

    PubMed

    Xu, Chenghao; Zhu, Ling; Chan, Ting; Lu, Xiaoxi; Shen, Weiyong; Madigan, Michele C; Gillies, Mark C; Zhou, Fanfan

    2016-02-01

    Chloroquine (CQ) and hydroxychloroquine (HCQ) are widely used to treat malaria and inflammatory diseases, long-term usage of which often causes severe side effects, especially retinopathy. Solute carrier transporters (SLCs) are important proteins responsible for the cellular uptake of endogenous and exogenous substances. Inhibitors competing with transporter substrates for SLCs often results in unfavorable toxicities and unsatisfactory therapeutic outcomes. We investigated the inhibitory effect of CQ and HCQ on substrate uptake mediated through a range of important SLC transporters in overexpressing human embryonic kidney (HEK293) cells. Our data revealed that both CQ and HCQ potently inhibit the uptake activity of organic anion transporting polypeptide 1A2 (OATP1A2). We recently reported OATP1A2 to be expressed in human retinal pigment epithelium (RPE), where it mediates cellular uptake of all-trans-retinol (atROL), a key step in the classical visual cycle. In this study, we demonstrate that CQ and HCQ could markedly impair atROL uptake in OATP1A2-expressing HEK293 cells and more importantly, in primary human RPE cells. Our study shows that CQ and HCQ are novel inhibitors of OATP1A2 and significantly impair OATP1A2-mediated substrate uptake, particularly transport of atROL into the RPE. This effect may compromise the function of the classic visual cycle leading to vision impairment and contribute to the retinopathy observed clinically in patients using CQ or HCQ.

  5. Imaging Nuclear Morphology and Organization in Cleared Plant Tissues Treated with Cell Cycle Inhibitors.

    PubMed

    de Souza Junior, José Dijair Antonino; de Sa, Maria Fatima Grossi; Engler, Gilbert; Engler, Janice de Almeida

    2016-01-01

    Synchronization of root cells through chemical treatment can generate a large number of cells blocked in specific cell cycle phases. In plants, this approach can be employed for cell suspension cultures and plant seedlings. To identify plant cells in the course of the cell cycle, especially during mitosis in meristematic tissues, chemical inhibitors can be used to block cell cycle progression. Herein, we present a simplified and easy-to-apply protocol to visualize mitotic figures, nuclei morphology, and organization in whole Arabidopsis root apexes. The procedure is based on tissue clearing, and fluorescent staining of nuclear DNA with DAPI. The protocol allows carrying out bulk analysis of nuclei and cell cycle phases in root cells and will be valuable to investigate mutants like overexpressing lines of genes disturbing the plant cell cycle.

  6. Belatacept As an Alternative to Calcineurin Inhibitors in Patients with Solid Organ Transplants.

    PubMed

    Kumar, Dhiren; LeCorchick, Spencer; Gupta, Gaurav

    2017-01-01

    The goal of immunosuppression in transplantation has shifted to improving long-term outcomes, reducing drug-induced toxicities while preserving the already excellent short-term outcomes. Long-term gains in solid organ transplantation have been limited at least partly due to the nephrotoxicity and metabolic side effects of calcineurin inhibitors (CNIs). The alloimmune response requires activation of the costimulatory pathway for T cell proliferation and amplification. Belatacept is a molecule that selectively blocks T cell costimulation. In June 2011, the U.S. Food and Drug Administration approved it for maintenance immunosuppression in kidney transplantation based on two open-label, randomized, phase III trials. Since its introduction, belatacept has shown promise in both short- and long-term renal transplant outcomes in several other trials. It exhibits a superior side effect profile compared to CNIs with a comparable efficacy. Across all solid organ transplants, the burden of chronic kidney disease, its associated cardiovascular morbidity, mortality, and inferior patient/allograft survival is a well-documented problem. In this review, we aim to discuss the evidence behind the use of belatacept in solid organ transplants as an effective alternative to CNIs for renal rescue in patients with acute and/or chronic kidney injury.

  7. Corrosion and corrosivity monitoring system

    NASA Astrophysics Data System (ADS)

    Braunling, Russ; Dietrich, Paul

    2005-05-01

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

  8. A Multifunctional Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, L. M.; Hintze, P. E.; Li, W.; Buhrow, J. W.; Jolley, S. T.

    2011-01-01

    This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

  9. Corrosive Wear in Wet Ore Grinding Systems

    NASA Astrophysics Data System (ADS)

    Jones, Denny A.

    1985-06-01

    Wear processes in ball and rod mills have recently received increased attention in order to increase efficiency and conserve grinding media. Direct removal of metal from the grinding media surface by abrasive wear occurs in both dry and wet grinding. Additional corrosive wear is apparent during wet grinding, in which less resistant corrosion product films are abraded away. Inhibitors and higher pH solutions, in which corrosion product films are more tenacious, improve wear resistance during wet grinding. Softer surfaces are less resistant to corrosive wear, suggesting that film formation and subsequent film abrasion on newly furrowed surfaces must be a factor.

  10. Role of temperature, chlorine, and organic matter in copper corrosion by-product release in soft water.

    PubMed

    Boulay, N; Edwards, M

    2001-03-01

    Soft, low alkalinity drinking waters tend to cause relatively high copper corrosion by-product release in plumbing systems. Long-term tests (6-8 months) in a synthetic, microbially stable soft tap water confirmed that lower pHs and higher temperatures increased copper release to water. Soluble copper release increased at lower temperature and lower pH. Low levels of free chlorine (0.7 mg/L) slightly increased copper release at pH 9.5, in marked contrast to the dramatic reductions in copper release that have been observed in soft waters in which Type III pitting corrosion is occurring. Gum xanthan and sodium alginate produced a microbially unstable water that reduced the pH and DO during stagnation in pipes--these indirect effects far outweighed their possible role in chelation or other modes of direct attack on copper surfaces.

  11. Self-assembly of cobalt-centered metal organic framework and multiwalled carbon nanotubes hybrids as a highly active and corrosion-resistant bifunctional oxygen catalyst

    NASA Astrophysics Data System (ADS)

    Fang, Yiyun; Li, Xinzhe; Li, Feng; Lin, Xiaoqing; Tian, Min; Long, Xuefeng; An, Xingcai; Fu, Yan; Jin, Jun; Ma, Jiantai

    2016-09-01

    Metal organic frameworks (MOF) derived carbonaceous materials have emerged as promising bifunctional oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) catalysts for electrochemical energy conversion and storage. But previous attempts to overcome the poor electrical conductivity of MOFs hybrids involve a harsh high-template pyrolytic process to in situ form carbon, which suffer from extremely complex operation and inevitable carbon corrosion at high positive potentials when OER is operated. Herein, a self-assembly approach is presented to synthesize a non-precious metal-based, high active and strong durable Co-MOF@CNTs bifunctional catalyst for OER and ORR. CNTs not only improve the transportation of the electrons but also can sustain the harsh oxidative environment of OER without carbon corrosion. Meanwhile, the unique 3D hierarchical structure offers a large surface area and stable anchoring sites for active centers and CNTs, which enables the superior durability of hybrid. Moreover, a synergistic catalysis of Co(II), organic ligands and CNTs will enhance the bifunctional electrocatalytic performance. Impressively, the hybrid exhibits comparable OER and ORR catalytic activity to RuO2 and 20 wt% Pt/C catalysts and superior stability. This facile and versatile strategy to fabricating MOF-based hybrids may be extended to other electrode materials for fuel cell and water splitting applications.

  12. Using self-organizing map (SOM) and support vector machine (SVM) for classification of selectivity of ACAT inhibitors.

    PubMed

    Wang, Ling; Wang, Maolin; Yan, Aixia; Dai, Bin

    2013-02-01

    Using a self-organizing map (SOM) and support vector machine, two classification models were built to predict whether a compound is a selective inhibitor toward the two Acyl-coenzyme A: cholesterol acyltransferase (ACAT) isozymes, ACAT-1 and ACAT-2. A dataset of 97 ACAT inhibitors was collected. For each molecule, the global descriptors, 2D and 3D property autocorrelation descriptors and autocorrelation of surface properties were calculated from the program ADRIANA.Code. The prediction accuracies of the models (based on the training/ test set splitting by SOM method) for the test sets are 88.9 % for SOM1, 92.6 % for SVM1 model. In addition, the extended connectivity fingerprints (ECFP_4) for all the molecules were calculated and the structure-activity relationship of selective ACAT inhibitors was summarized, which may help find important structural features of inhibitors relating to the selectivity of ACAT isozymes.

  13. A Multifunctional Smart Coating for Autonomous Corrosion Control

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Buhrow, Jerry W.; Jolley, Scott T.

    2012-01-01

    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 micro-encapsulation 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 needed. Corrosion indicators as well as corrosion inhibitors have been incorporated into microcapsules, blended into several paint systems, and tested for corrosion detection and protection efficacy. This

  14. Fighting Corrosion

    NASA Technical Reports Server (NTRS)

    2004-01-01

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

  15. Inhibition of slug front corrosion in multiphase flow conditions

    SciTech Connect

    Chen, H.J.; Jepson, W.P.

    1998-12-31

    Corrosion at the slug front at the bottom of a pipeline is identified as one of the worst cases of corrosion occurring in the pipeline which carries unprocessed multiphase production with a high level of CO{sub 2} gas. One objective of the study in recommending a subsea completion to shore was to determine if commercial corrosion inhibitors can control this type of corrosion using carbon steel pipeline. Thus, inhibitors which showed excellent performance in the lab using the Rotating Cylinder Electrode system (RCE) were further evaluated to confirm their performance in a flow loop simulating the test conditions predicted from the flow modeling for the proposed pipeline. The performance profile of two commercial inhibitors were determined in a 4 in. flow loop at 7O C, 100 psig CO{sub 2} partial pressure in corrosive brines with or without ethylene glycol and/or light hydrocarbon. Results showed that the carbon steel pipeline could be adequately protected at low temperature using a commercial corrosion inhibitor to meet the designed life of the pipeline. Ethylene glycol, which is used in the pipeline to prevent hydrate formation, reduces the corrosivity of the brine and gives no effect on inhibitor performance under the slug flow conditions. A good agreement in inhibitor performance was observed between the flow loop and the RCE testing. The uninhibited corrosion rate of the test brine in this study is in good agreement with the predicted value using deWaard and Williams correlation for CO{sub 2} corrosion.

  16. Nitric oxide synthase inhibitors attenuate transforming-growth-factor-beta 1-stimulated capillary organization in vitro.

    PubMed Central

    Papapetropoulos, A.; Desai, K. M.; Rudic, R. D.; Mayer, B.; Zhang, R.; Ruiz-Torres, M. P.; García-Cardeña, G.; Madri, J. A.; Sessa, W. C.

    1997-01-01

    Angiogenesis is a complex process involving endothelial cell (EC) proliferation, migration, differentiation, and organization into patent capillary networks. Nitric oxide (NO), an EC mediator, has been reported to be antigenic as well as proangiogenic in different models of in vivo angiogenesis. Our aim was to investigate the role of NO in capillary organization using rat microvascular ECs (RFCs) grown in three-dimensional (3D) collagen gels. RFCs placed in 3D cultures exhibited extensive tube formation in the presence of transforming growth factor-beta 1. Addition of the NO synthase (NOS) inhibitors L-nitro-arginine methylester (L-NAME, 1 mmol/L) or L-monomethyl-nitro-l-arginine (1 mmol/L) inhibited tube formation and the accumulation of nitrite in the media by approximately 50%. Incubation of the 3D cultures with excess L-arginine reversed the inhibitory effect of L-NAME on tube formation. In contrast to the results obtained in 3D cultures, inhibition of NO synthesis by L-NAME did not influence RFC proliferation in two-dimensional (2D) cultures or antagonize the ability of transforming growth factor-beta 1 to suppress EC proliferation in 2D cultures. Reverse transcriptase-polymerase chain reaction revealed the constitutive expression of all three NOS isoforms, neuronal, inducible, and endothelial NOSs, in 2D and 3D cultures. Moreover, Western blot analysis demonstrated the presence of immunoreactive protein for all NOS isoforms in 3D cultures of RFCs. In addition, in the face of NOS blockade, co-treatment with the NO donor sodium nitroprusside or the stable analog of cGMP, 8-bromo-cGMP, restored capillary tube formation. Thus, the autocrine production of NO and the activation of soluble guanylate cyclase are necessary events in the process of differentiation and in vitro capillary tube organization of RFCs. Images Figure 2 Figure 4 Figure 5 PMID:9137106

  17. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    PubMed

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2017-04-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A-the control, B-natural zeolite addition, and C-3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites andDMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

  18. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    PubMed

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2016-01-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance.

  19. Race, Calcineurin Inhibitor Exposure, and Renal Function After Solid Organ Transplantation.

    PubMed

    Yessayan, L; Shafiq, A; Peterson, E; Wells, K; Hu, Y; Williams, L K; Lanfear, D

    2015-12-01

    Calcineurin-inhibitor (CNI)-induced nephrotoxicity frequently complicates transplantation. African-Americans are at a greater risk of renal failure than the general population. We investigated whether race was an effect modifier of the relationship between CNI exposure and kidney function after nonrenal solid organ transplantation. This is a retrospective cohort study of 1609 patients who underwent initial nonrenal solid organ transplantation between January 2000 and June 2012. A central repository administrative database was queried electronically for demographics, comorbidities, and serial levels of tacrolimus, cyclosporine, and serum creatinine. Predictors of interest were total drug exposure of tacrolimus and cyclosporine (area under the concentration-time curve) and self-reported race. The outcome of interest was cumulative change in estimated glomerular filtration rate (GFR). There were 1109 patients treated with tacrolimus (271 African-Americans) and 500 patients treated with cyclosporine (113 African Americans). A decline in GFR over time was seen with total tacrolimus exposure (-1.3 mL/min/1.73 m(2) for every 5 ng/mL·year increase in tacrolimus) and total cyclosporine exposure (-1.1 mL/min/1.73 m(2) for every 50 ng/mL·year increase in cyclosporine). However, total CNI exposure effect on estimated GFR changes did not vary by race (P interaction was 0.9 for tacrolimus and 0.6 for cyclosporine). Total CNI exposure is associated with worsening kidney function among patients with nonrenal solid organ transplantation. However, African-American patients are not more vulnerable to chronic CNI-induced nephrotoxicity when compared to white patients. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Bringing Research into a First Semester Organic Chemistry Laboratory with the Multistep Synthesis of Carbohydrate-Based HIV Inhibitor Mimics

    ERIC Educational Resources Information Center

    Pontrello, Jason K.

    2015-01-01

    Benefits of incorporating research experiences into laboratory courses have been well documented, yet examples of research projects designed for the first semester introductory organic chemistry lab course are extremely rare. To address this deficiency, a Carbohydrate-Based human immunodeficiency virus (HIV) Inhibitor project consisting of a…

  1. Bringing Research into a First Semester Organic Chemistry Laboratory with the Multistep Synthesis of Carbohydrate-Based HIV Inhibitor Mimics

    ERIC Educational Resources Information Center

    Pontrello, Jason K.

    2015-01-01

    Benefits of incorporating research experiences into laboratory courses have been well documented, yet examples of research projects designed for the first semester introductory organic chemistry lab course are extremely rare. To address this deficiency, a Carbohydrate-Based human immunodeficiency virus (HIV) Inhibitor project consisting of a…

  2. Corrosion inhibition of a mild steel by aniline and alkylamines in acidic solutions

    SciTech Connect

    Luo, H.; Han, K.N.; Guan, Y.C.

    1998-09-01

    Corrosion inhibition of a mild steel in acid solutions by alkylamines (ALK-AM) and aniline hydrochloric (ANL-HCl) salts was investigated in the presence of sodium sulfate (Na{sub 2}SO{sub 4}) and sodium chloride (NaCl) using a potentiostat, a contact-angle goniometer, a scanning electron microscope (SEM), a Fourier transform infrared spectrometer (FTIR), and an atomic force microscope (AFM). Results showed chloride ions (Cl{sup {minus}}) had a pronounced effect on inhibition of amines and ANL for corrosion of mild steel. In the presence of Cl{sup {minus}} ions, cationic types of surfactants (ALK-AM and ANL) were attached to the surface through formation of chloride precipitate at the surface. In the absence of the organic inhibitors, corrosion initiated along grain boundaries of ferrite and pearlite structures. In the presence of the organic inhibitor, however, the steel surface was covered by an organic salt precipitation, and the corrosion rate was reduced significantly.

  3. Understanding corrosion inhibition with van der Waals DFT methods: the case of benzotriazole.

    PubMed

    Gattinoni, Chiara; Michaelides, Angelos

    2015-01-01

    The corrosion of materials is an undesirable and costly process affecting many areas of technology and everyday life. As such, considerable effort has gone into understanding and preventing it. Organic molecule based coatings can in certain circumstances act as effective corrosion inhibitors. Although they have been used to great effect for more than sixty years, how they function at the atomic-level is still a matter of debate. In this work, computer simulation approaches based on density functional theory are used to investigate benzotriazole (BTAH), one of the most widely used and studied corrosion inhibitors for copper. In particular, the structures formed by protonated and deprotonated BTAH molecules on Cu(111) have been determined and linked to their inhibiting properties. It is found that hydrogen bonding, van der Waals interactions and steric repulsions all contribute in shaping how BTAH molecules adsorb, with flat-lying structures preferred at low coverage and upright configurations preferred at high coverage. The interaction of the dehydrogenated benzotriazole molecule (BTA) with the copper surface is instead dominated by strong chemisorption via the azole moiety with the aid of copper adatoms. Structures of dimers or chains are found to be the most stable structures at all coverages, in good agreement with scanning tunnelling microscopy results. Benzotriazole thus shows a complex phase behaviour in which van der Waals forces play an important role and which depends on coverage and on its protonation state and all of these factors feasibly contribute to its effectiveness as a corrosion inhibitor.

  4. Sustainable Gel Electrolyte Containing Pyrazole as Corrosion Inhibitor and Dendrite Suppressor for Aqueous Zn/LiMn2 O4 Battery.

    PubMed

    Hoang, Tuan K A; Doan, The Nam Long; Cho, Julie Hyeonjoo; Su, Jane Ying Jun; Lee, Christine; Lu, Changyu; Chen, P

    2017-07-10

    The Zn anode in secondary aqueous batteries suffers from dendrite formation and corrosion. In this work, dendrite formation was suppressed by using a simple but new gel electrolyte containing fumed silica and an additive. The dendrite suppression was evidenced by chronoamperometry and ex situ scanning electron microscopy examinations. Pyrazole was implemented as the additive in the electrolyte. It was found that the presence of 0.2 wt % pyrazole in the electrolyte helped minimize both corrosion and dendrite formation. The Zn/LiMn2 O4 battery using pyrazole-containing gel electrolytes exhibited high cyclability up to 85 % capacity retention after 500 charge-discharge cycles at 4C. This was 8 % higher than the performance of the reference battery (using aqueous electrolyte containing 2 m Li2 SO4 and 1 m ZnSO4 ). Furthermore, self-discharge of the battery with the pyrazole-containing gel electrolyte was suppressed, as evidenced by an open-circuit voltage loss that was 20 % lower than for the reference battery after 24 h monitoring. Float-charge current density under constant voltage (2.1 V) also significantly decreased from approximately 8.0 to 3-6 μA. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Synthesis of organic nitrates of luteolin as a novel class of potent aldose reductase inhibitors.

    PubMed

    Wang, Qi-Qin; Cheng, Ning; Zheng, Xiao-Wei; Peng, Sheng-Ming; Zou, Xiao-Qing

    2013-07-15

    Aldose reductase (AR) plays an important role in the design of drugs that prevent and treat diabetic complications. Aldose reductase inhibitors (ARIs) have received significant attentions as potent therapeutic drugs. Based on combination principles, three series of luteolin derivatives were synthesised and evaluated for their AR inhibitory activity and nitric oxide (NO)-releasing capacity in vitro. Eighteen compounds were found to be potent ARIs with IC50 values ranging from (0.099±0.008) μM to (2.833±0.102) μM. O(7)-Nitrooxyethyl-O(3'),O(4')-ethylidene luteolin (La1) showed the most potent AR inhibitory activity [IC50=(0.099±0.008) μM]. All organic nitrate derivatives released low concentrations of NO in the presence of l-cysteine. Structure-activity relationship studies suggested that introduction of an NO donor, protection of the catechol structure, and the ether chain of a 2-carbon spacer as a coupling chain on the luteolin scaffold all help increase the AR inhibitory activity of the resulting compound. This class of NO-donor luteolin derivatives as efficient ARIs offer a new concept for the development and design of new drug for preventive and therapeutic drugs for diabetic complications.

  6. Stoichiometry, inhibitor sensitivity, and organization of manganese associated with photosynthetic oxygen evolution.

    PubMed

    Yocum, C F; Yerkes, C T; Blankenship, R E; Sharp, R R; Babcock, G T

    1981-12-01

    Chloroplast thylakoid membranes isolated in the presence of EDTA retain high rates of O(2) evolution (>/=340 mumol.h(-1).mg chlorophyll(-1)) but contain no Mn(2+) that is detectable by electron paramagnetic resonance (EPR) at room temperature. The total Mn(2+) content of these preparations is 4.6 per 400 chlorophylls; 0.6 Mn(2+) can be released by addition of Ca(2+), a treatment that does not affect O(2) evolution. The remaining Mn(2+) (4 per 400 chlorophylls) appears to be functionally associated with O(2) evolution activity. Inhibition by Tris, NH(2)OH, or heat will release a small fraction of Mn(2+) from these membranes ( approximately 25% with Tris, for example). Addition of Ca(2+) further enhances Mn(2+) release so that for Tris and for NH(2)OH, 2 and 3, respectively, Mn(2+) per 400 chlorophylls are extracted from the O(2)-evolving complex. Based on the microwave power-saturation properties of the EPR signal IIf, which arises from an intermediate electron carrier in the water splitting process, it appears that one of the four Mn(2+) associated with photosystem II is uniquely sensitive to Tris. A new model is proposed for the organization and inhibitor sensitivity of manganese in the O(2)-evolving complex.

  7. Stoichiometry, inhibitor sensitivity, and organization of manganese associated with photosynthetic oxygen evolution

    PubMed Central

    Yocum, C. F.; Yerkes, C. T.; Blankenship, R. E.; Sharp, R. R.; Babcock, G. T.

    1981-01-01

    Chloroplast thylakoid membranes isolated in the presence of EDTA retain high rates of O2 evolution (≥340 μmol·h-1·mg chlorophyll-1) but contain no Mn2+ that is detectable by electron paramagnetic resonance (EPR) at room temperature. The total Mn2+ content of these preparations is 4.6 per 400 chlorophylls; 0.6 Mn2+ can be released by addition of Ca2+, a treatment that does not affect O2 evolution. The remaining Mn2+ (4 per 400 chlorophylls) appears to be functionally associated with O2 evolution activity. Inhibition by Tris, NH2OH, or heat will release a small fraction of Mn2+ from these membranes (≈25% with Tris, for example). Addition of Ca2+ further enhances Mn2+ release so that for Tris and for NH2OH, 2 and 3, respectively, Mn2+ per 400 chlorophylls are extracted from the O2-evolving complex. Based on the microwave power-saturation properties of the EPR signal IIf, which arises from an intermediate electron carrier in the water splitting process, it appears that one of the four Mn2+ associated with photosystem II is uniquely sensitive to Tris. A new model is proposed for the organization and inhibitor sensitivity of manganese in the O2-evolving complex. PMID:16593134

  8. Influence of NOM on copper corrosion

    SciTech Connect

    Korshin, G.V.; Ferguson, J.F.; Perry, S.A.L.

    1996-07-01

    Natural organic matter (NOM) profoundly affected the corrosion of copper in a moderately alkaline synthetic water. It decreased the rate of corrosion, increased the rate of copper leaching, and dispersed crystalline inorganic corrosion products. The interaction of NOM with corrosion products was modeled using separate phase of malachite and cuprous oxide. The authors concluded that NOM promotes the formation of pits in a certain narrow range of concentrations (0.1--0.2 mg/L in laboratory tests) and suppresses this type of corrosion at higher dosages. At low DOC concentrations, the main interaction between NOM and the surfaces of corroding metal and corrosion products is adsorption. The influence of NOM on corrosion of metals in real distribution systems must be studied in relation to long periods of surface aging, flow rate, concentration and type of oxidants, pH, and alkalinity.

  9. Hazardous and Corrosive Gas Production in the Radiolysis of Water/Organic Mixtures in Model TRU Waste

    SciTech Connect

    LaVerne, Jay A.

    2004-12-01

    Scope. The radiation chemistry of aqueous systems containing chlorinated hydrocarbons is investigated using a multi-pronged approach employing 60Co gamma ray and alpha particle irradiation experiments in conjunction with diffusion-kinetic modeling incorporating track structure simulations. The goal is to determine mechanisms, kinetics, and yields for the formation of potentially explosive gases and corrosive agents, such as H2 and HCl, respectively, in the radiolysis of water-organic mixtures. The information obtained is of a fundamental nature, but the radiation chemical systems studied are found throughout the DOE portfolio and are important in radioactive waste remediation and management. Program Highlights. Radiation-induced production of H2 and HCl from chlorinated hydrocarbons. 60Co gamma-radiolysis experiments and stochastic kinetic modeling have been used to investigated the radiation-induced yield of H2 and Cl- from aqueous solutions of 1,2-dichloroethane (1,2-DCE) and 1,1-dichloroethane (1,1-DCE) over the concentration range 1-80 mM. In deoxygenated solution, the yield of H2 from both 1,2-DCE and 1,1-DCE solutions decreases as the concentration of DCE is increased. The decrease in the H2 yield shows that the reaction of H atom with DCE does not lead to the production of H2. This observation is unexpected and reflects the reverse of the effect seen in the gas phase, where the reaction of H atom with 1,2-DCE and 1,1-DCE leads to the production of H2. The yield of Cl- from 1,2-DCE and 1,1-DCE solutions increases slightly from 2.8 ions/100eV to 3.6 over the concentration range 10-50 mM, demonstrating the increased competition of the DCE with intra-track processes. Comparison of the measured yields of Cl- with the predictions of stochastic kinetic modeling shows that the reactions of eaq- with 1,2-DCE and with 1,1-DCE are quantitative, and that the reaction of H atom with both DCEs leads to the production of Cl- (and Haq+). In aerated solution, the yield of Cl

  10. Inhibition of Corrosion in Catapult Water Brake Tanks

    DTIC Science & Technology

    1976-01-01

    effect of pH treat- ment is that above a pH of approximately 10, insoluble salts of calcium and magnesium precipitated. This resulted in scale...ethylenediaminetetraacetic acid ( EDTA ) are effective in reducing the corrosion of steel in the presence of chlorides". Ferric EDTA is an inorganic and maleic...hydrazide an organic inhibitor. Sodium phosphate and L._ IND.WAEC.14JUf REV. a.ee) NAEC-ENG 7878 ,* ,, No*. lot PAGE II r 1 odium hexametaphosphate are well

  11. Application of nano-sized TiO2 as an inhibitor of stress corrosion cracking in the steam generator tube materials.

    PubMed

    Kim, Kyung Mo; Lee, Eun Hee; Kim, Uh Chul; Choi, Byung Seon

    2010-01-01

    Several chemicals were studied to suppress the damage due to a stress corrosion cracking (SCC) of the steam generator (SG) tubes in nuclear power plants. SCC tests were carried out to investigate the performance of TiO2 on several types of SG tube materials. The SCC tests were conducted by using an m-RUB specimen in a 10% NaOH solution at a temperature of 315 degrees C. The test with the addition of TiO2 showed a decrease in the SCC rate for the SG tubing materials. In order to improve the inhibition property in a crevice of TiO2, a sonochemical technique was applied to reduce the size of the TiO2 particle. From the SCC tests with the RUB specimen, the SG tube materials showed an enhanced cracking resistance with the addition of nano-sized TiO2 and the surface property was also changed.

  12. Corrosive wear principles

    SciTech Connect

    Schumacher, W.J.

    1993-12-31

    The dual effects of corrosion and wear operate together in such industries as paper and pulp, coal handling, mining, and sugar beet extraction. There is a synergistic effect that causes far greater wastage to carbon steels, alloy steels, and even much more abrasion resistant cast irons. Several laboratory and in situ studies have been conducted to better understand the contributions of corrosion and wear to the wastage process. The environmental conditions are usually set by the process. However, there are a few instances where inhibitors as sodium nitrite, sodium chromate, and sodium metasilicate have been successfully used to reduce metal wastage of carbon steels. Hardness has been found to be an unreliable guide to performance under wet sliding conditions. Heat treated alloy steels and cast irons are inferior to stainless steels. Even distilled water is too severe a corrodent for steels. While the austenitic stainlesses perform the best, cold rolling to increase hardness does not further improve their performance. The surface roughness of stainless steels gets smoother during corrosive wear testing while it gets rougher for the alloy steels. This observation substantiated the reputation of improved slideability for stainless alloys over alloy steels.

  13. Mechanisms of Inhibition of Crevice Corrosion in Alloy 22

    SciTech Connect

    Rebak, Raul B.

    2007-07-01

    Alloy 22 may be susceptible to crevice corrosion in chloride-containing environments, especially at temperatures above ambient. The presence of oxy-anions, especially nitrate, minimizes or eliminates the susceptibility of Alloy 22 to crevice corrosion. Other anions such as sulfate, carbonate and fluoride were also reported as inhibitors of crevice corrosion in Alloy 22. It is argued that the occurrence of crevice corrosion is due to the formation of hydrochloric acid solution in the creviced region. Inhibitors act by eliminating the occurrence of hydrochloric acid or by hampering its action. (author)

  14. Potent inhibitors of human organic anion transporters 1 and 3 from clinical drug libraries: discovery and molecular characterization.

    PubMed

    Duan, Peng; Li, Shanshan; Ai, Ni; Hu, Longqin; Welsh, William J; You, Guofeng

    2012-11-05

    Transporter-mediated drug-drug interactions in the kidney dramatically influence the pharmacokinetics and other clinical effects of drugs. Human organic anion transporters 1 (hOAT1) and 3 (hOAT3) are the major transporters in the basolateral membrane of kidney proximal tubules, mediating the rate-limiting step in the elimination of a broad spectrum of drugs. In the present study, we screened two clinical drug libraries against hOAT1 and hOAT3. Of the 727 compounds screened, 92 compounds inhibited hOAT1 and 262 compounds inhibited hOAT3. When prioritized based on the peak unbound plasma concentrations of these compounds, three inhibitors for hOAT1 and seven inhibitors for hOAT3 were subsequently identified with high inhibitory potency (>95%). Computational analyses revealed that inhibitors and noninhibitors can be differentiated from each other on the basis of several physicochemical features, including number of hydrogen-bond donors, number of rotatable bonds, and topological polar surface area (TPSA) for hOAT1; and molecular weight, number of hydrogen-bond donors and acceptors, TPSA, partition coefficient (log P(7.4)), and polarizability for hOAT3. Pharmacophore modeling identified two common structural features associated with inhibitors for hOAT1 and hOAT3, viz., an anionic hydrogen-bond acceptor atom, and an aromatic center separated by ∼5.7 Å. Such model provides mechanistic insights for predicting new OAT inhibitors.

  15. CORROSION INHIBITION

    DOEpatents

    Cartledge, G.H.

    1958-06-01

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

  16. Recent Developments on Microencapsulation for Autonomous Corrosion Protection

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Li, Wenyan; Buhrow, Jerry W.; Fitzpatrick, Lilliana; Jolley, Scott T.; Surma, Jan M.; Pearman, Benjamin P.; Zhang, Xuejun

    2014-01-01

    This work concerns recent progress in the development of a multifunctional smart coating based on microencapsulation for the autonomous control of corrosion. Microencapsulation allows the incorporation of desired corrosion control functionalities, such as early corrosion detection and inhibition through corrosion controlled release of corrosion indicators and inhibitors, as well as self-healing agent release when mechanical damage occurs.While proof-of-concept results have been reported previously, more recent efforts have been concentrated in technical developments to improve coating compatibility, synthesis procedure scalability, as well as fine tuning the release property of encapsulated active agents.

  17. NITRIC OXIDE SYNTHASE INHIBITOR L-NAMEAFFECTS ARABIDOPSIS ROOT GROWTH, MORPHOLOGY AND MICROTUBULE ORGANIZATION.

    PubMed

    Yu A, Krasylenko; A I, Yemets; Ya B, Blume

    2017-10-05

    The presence of evolutionarily conserved NOS or NOS-like enzymes in land plants different than those in animals is still unclear, despite their activity has been revealed in cytosol and some organelles. At the same time, the emerging evidence for the importance of L-arginine-dependent pathways of NO synthesis in plant cells is still accumulating. The aim of our study was to reveal physiological effects on growth and differentiation processes and microtubular cytoskeleton organization of the competitive mammalian NO synthase inhibitor L-NAME. Thus, the treatment of Arabidopsis with L-NAME (50 μM-1 mM) caused dose- and time-dependent inhibition of primary roots growth. Moreover, the morphology of primary roots under the influence of L-NAME also underwent changes. L-NAME (>100 μM) induced the formation of novel over-elongated root hairs in shortened elongation zone, while in higher concentrations (500 μM) it caused a slight swelling of epidermal cells in differentiation zone. L-NAME also provoked microtubule reorganization in epidermal cells of different root growth zones. Thus, L-NAME at concentrations of 50 μM-1 mM induces cortical microtubules randomization and/or depolymerization in epidermal cells of the root apex, meristem, transition, elongation and differentiation zones after 2 h of treatment. Disordered microtubules in trichoblasts could initiate the formation of actively elongating root hairs that reveals longitudinal microtubules ensuring their active growth at 24 h of treatment. Therefore, L-NAME inhibits primary root growth, induces the differentiation processes in roots and reorganizes cortical microtubules in epidermal root cells suggesting the importance of L-arginine-dependent pathways of NO synthesis in plants. This article is protected by copyright. All rights reserved.

  18. The pharmacology of novel acetylcholinesterase inhibitors, (+/-)-huprines Y and X, on the Torpedo electric organ.

    PubMed

    Ros, E; Aleu, J; Gómez de Aranda, I; Muñoz-Torrero, D; Camps, P; Badia, A; Marsal, J; Solsona, C

    2001-06-08

    The effects of the tacrine-huperzine A hybrid acetylcholinesterase inhibitors, (+/-)-12-amino-3-chloro-9-methyl-6,7,10,11-tetrahydro-7,11-methanocycloocta[b]quinoline hydrochloride ((+/-)-huprine Y) and (+/-)-12-amino-3-chloro-9-ethyl-6,7,10,11-tetrahydro-7,11-methanocycloocta[b]quinoline hydrochloride ((+/-)-huprine X), were tested on spontaneous synaptic activity by measuring the amplitude, the rise time, the rate of rise, the half-width and the area or the electrical charge of the miniature endplate potentials (m.e.p.ps) recorded extracellularly on Torpedo electric organ fragments. (+/-)-Huprine Y and (+/-)-huprine X at a concentration of 500 nM increased all the m.e.p.p. variables analyzed. The effect of (+/-)-huprine Y was smaller than that of (+/-)-huprine X for all the variables except for the rate of rise where there was no significant difference. The effects of these drugs were also tested on nicotinic receptors by analyzing the currents elicited by acetylcholine (100 microM) in Xenopus laevis oocytes, transplanted with membranes from Torpedo electric organ. Both drugs inhibited the currents in a reversible manner, (+/-)-huprine Y (IC(50)=452 nM) being more effective than (+/-)-huprine X (IC(50)=4865 nM). The Hill coefficient was 0.5 for both drugs. The inhibition of the nicotinic receptor was voltage-dependent and decreased at depolarizing potentials, and there was no significant difference in the effects between (+/-)-huprine Y and (+/-)-huprine X at concentrations near to their IC(50) values. At depolarizing potentials between -20 and +15 mV, these drugs did not have any detectable effect on the blockade of the nicotinic receptor. Both huprines increased the desensitization of the nicotinic receptors since the current closed quickly in the presence of the drugs, and there was no significant difference in this effect between (+/-)-huprine Y (500 nM) and (+/-)-huprine X (5 microM). We conclude that (+/-)-huprine Y and (+/-)-huprine X increase the level of

  19. Corrosion and corrosion prevention in gas turbines

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  20. Fungal-induced corrosion of wire rope

    SciTech Connect

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

    1995-10-01

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

  1. Microencapsulation Technologies for Corrosion Protective Coating Applications

    NASA Technical Reports Server (NTRS)

    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.

  2. LIM kinase inhibitors disrupt mitotic microtubule organization and impair tumor cell proliferation

    PubMed Central

    Mardilovich, Katerina; Baugh, Mark; Crighton, Diane; Kowalczyk, Dominika; Gabrielsen, Mads; Munro, June; Croft, Daniel R.; Lourenco, Filipe; James, Daniel; Kalna, Gabriella; McGarry, Lynn; Rath, Oliver; Shanks, Emma; Garnett, Mathew J.; McDermott, Ultan; Brookfield, Joanna; Charles, Mark; Hammonds, Tim; Olson, Michael F.

    2015-01-01

    The actin and microtubule cytoskeletons are critically important for cancer cell proliferation, and drugs that target microtubules are widely-used cancer therapies. However, their utility is compromised by toxicities due to dose and exposure. To overcome these issues, we characterized how inhibition of the actin and microtubule cytoskeleton regulatory LIM kinases could be used in drug combinations to increase efficacy. A previously-described LIMK inhibitor (LIMKi) induced dose-dependent microtubule alterations that resulted in significant mitotic defects, and increased the cytotoxic potency of microtubule polymerization inhibitors. By combining LIMKi with 366 compounds from the GSK Published Kinase Inhibitor Set, effective combinations were identified with kinase inhibitors including EGFR, p38 and Raf. These findings encouraged a drug discovery effort that led to development of CRT0105446 and CRT0105950, which potently block LIMK1 and LIMK2 activity in vitro, and inhibit cofilin phosphorylation and increase αTubulin acetylation in cells. CRT0105446 and CRT0105950 were screened against 656 cancer cell lines, and rhabdomyosarcoma, neuroblastoma and kidney cancer cells were identified as significantly sensitive to both LIMK inhibitors. These large-scale screens have identified effective LIMK inhibitor drug combinations and sensitive cancer types. In addition, the LIMK inhibitory compounds CRT0105446 and CRT0105950 will enable further development of LIMK-targeted cancer therapy. PMID:26540348

  3. Microbiological influences in 'blue water' copper corrosion.

    PubMed

    Critchley, M M; Pasetto, R; O'Halloran, R J

    2004-01-01

    To investigate the influence of micro-organisms associated with copper corrosion on 'blue water' corrosion in drinking water. Laboratory rigs comprising of polycarbonate containers attached to annealed copper plumbing tubes were filled with Melbourne drinking water and sterilized by autoclaving. The copper tubes were inoculated with sterile or nonsterile extracts obtained from corroding copper and allowed to stand for 7 days. The extracts were drained and the tubes flushed and filled with sterile water from the rig. The water within the tubes was removed weekly for analysis and the tubes were refilled with freshly aerated water. The tube water sampled was analysed for pH, total copper and the presence of micro-organisms. Sterile rigs and rigs containing nonsterile water, both without tube inoculums, were used as controls. The results demonstrated that tubes inoculated with nonsterile corrosion extracts showed statistically higher copper release compared with the other rigs. Copper release as blue water was only observed after a lag period of 9 weeks. The internal surfaces of tubes releasing copper showed significant amounts of corrosion products and the presence of biofilm. Bacteria isolated from the corroding tubes included Acidovorax spp. and Sphingomonas sp. The results demonstrate a microbial role in blue water, as corrosion was induced in new copper tubes by exposure to nonsterile copper corrosion products. The potential for micro-organisms present in corrosion products to initiate blue water corrosion presents significant implications for the management of corrosion in distribution systems. Copyright 2004 The Society for Applied Microbiology

  4. POTENT INHIBITORS OF HUMAN ORGANIC ANION TRANSPORTERS 1 AND 3 FROM CLINICAL DRUG LIBRARIES: DISCOVERY AND MOLECULAR CHARACTERIZATION

    PubMed Central

    Duan, Peng; Li, Shanshan; Ai, Ni; Hu, Longqin; Welsh, William J.; You, Guofeng

    2012-01-01

    Transporter-mediated drug-drug interactions in the kidney dramatically influence the pharmacokinetics and other clinical effects of drugs. Human organic anion transporters 1 (hOAT1) and 3 (hOAT3) are the major transporters in the basolateral membrane of kidney proximal tubules, mediating the rate-limiting step in the elimination of a broad spectrum of drugs. In the present study, we screened two clinical drug libraries against hOAT1 and hOAT3. Of the 727 compounds screened, 92 compounds inhibited hOAT1 and 262 compounds inhibited hOAT3. When prioritized based on the peak unbound plasma concentrations of these compounds, three inhibitors for hOAT1 and seven inhibitors for hOAT3 were subsequently identified with high inhibitory potency (>95%). Computational analyses revealed that inhibitors and non-inhibitors can be differentiated from each other on the basis of several physico-chemical features, including: number of hydrogen-bond donors, number of rotatable bonds, and topological polar surface area (TPSA) for hOAT1; and molecular weight, number of hydrogen-bond donors and acceptors, TPSA, partition coefficient (Log P7.4), and polarizability for hOAT3. Pharmacophore modeling identified two common structural features associated with inhibitors for hOAT1 and hOAT3, viz., an anionic hydrogen-bond acceptor atom, and an aromatic center separated by ~5.7 Å. Such model provides mechanistic insights for predicting new OAT inhibitors. PMID:22973893

  5. Effects of combined application of organic and inorganic fertilizers plus nitrification inhibitor DMPP on nitrogen runoff loss in vegetable soils.

    PubMed

    Yu, Qiaogang; Ma, Junwei; Zou, Ping; Lin, Hui; Sun, Wanchun; Yin, Jianzhen; Fu, Jianrong

    2015-01-01

    The application of nitrogen fertilizers leads to various ecological problems such as large amounts of nitrogen runoff loss causing water body eutrophication. The proposal that nitrification inhibitors could be used as nitrogen runoff loss retardants has been suggested in many countries. In this study, simulated artificial rainfall was used to illustrate the effect of the nitrification inhibitor DMPP (3,4-dimethyl pyrazole phosphate) on nitrogen loss from vegetable fields under combined organic and inorganic nitrogen fertilizer application. The results showed that during the three-time simulated artificial rainfall period, the ammonium nitrogen content in the surface runoff water collected from the DMPP application treatment increased by 1.05, 1.13, and 1.10 times compared to regular organic and inorganic combined fertilization treatment, respectively. In the organic and inorganic combined fertilization with DMPP addition treatment, the nitrate nitrogen content decreased by 38.8, 43.0, and 30.1% in the three simulated artificial rainfall runoff water, respectively. Besides, the nitrite nitrogen content decreased by 95.4, 96.7, and 94.1% in the three-time simulated artificial rainfall runoff water, respectively. A robust decline in the nitrate and nitrite nitrogen surface runoff loss could be observed in the treatments after the DMPP addition. The nitrite nitrogen in DMPP addition treatment exhibited a significant low level, which is near to the no fertilizer application treatment. Compared to only organic and inorganic combined fertilizer treatment, the total inorganic nitrogen runoff loss declined by 22.0 to 45.3% in the organic and inorganic combined fertilizers with DMPP addition treatment. Therefore, DMPP could be used as an effective nitrification inhibitor to control the soil ammonium oxidation in agriculture and decline the nitrogen runoff loss, minimizing the nitrogen transformation risk to the water body and being beneficial for the ecological environment.

  6. Shadow corrosion

    NASA Astrophysics Data System (ADS)

    Ramasubramanian, N.

    2004-07-01

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

  7. Discriminating of ATP competitive Src kinase inhibitors and decoys using self-organizing map and support vector machine.

    PubMed

    Yan, Aixia; Hu, Xiaoying; Wang, Kai; Sun, Jing

    2013-02-01

    A data set containing 686 Src kinase inhibitors and 1,941 Src kinase non-binding decoys was collected and used to build two classification models to distinguish inhibitors from decoys. The data set was randomly split into a training set (458 inhibitors and 972 decoys) and a test set (228 inhibitors and 969 decoys). Each molecule was represented by five global molecular descriptors and 18 2D property autocorrelation descriptors calculated using the program ADRIANA.Code. Two machine learning methods, a Kohonen's self-organizing map (SOM) and a support vector machine (SVM), were utilized for the training and classification. For the test set, classification accuracy (ACC) of 99.92% and Matthews correlation coefficient (MCC) of 0.98 were achieved for the SOM model; ACC of 99.33% and MCC of 0.98 were obtained for the SVM model. Some molecular properties, such as molecular weight, number of atoms in a molecule, hydrogen bond properties, polarizabilities, electronegativities, and hydrophobicities, were found to be important for the inhibition of Src kinase.

  8. Classification of Inhibitors of Hepatic Organic Anion Transporting Polypeptides (OATPs): Influence of Protein Expression on Drug–Drug Interactions

    PubMed Central

    2012-01-01

    The hepatic organic anion transporting polypeptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug–drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors. PMID:22541068

  9. Classification of inhibitors of hepatic organic anion transporting polypeptides (OATPs): influence of protein expression on drug-drug interactions.

    PubMed

    Karlgren, Maria; Vildhede, Anna; Norinder, Ulf; Wisniewski, Jacek R; Kimoto, Emi; Lai, Yurong; Haglund, Ulf; Artursson, Per

    2012-05-24

    The hepatic organic anion transporting polypeptides (OATPs) influence the pharmacokinetics of several drug classes and are involved in many clinical drug-drug interactions. Predicting potential interactions with OATPs is, therefore, of value. Here, we developed in vitro and in silico models for identification and prediction of specific and general inhibitors of OATP1B1, OATP1B3, and OATP2B1. The maximal transport activity (MTA) of each OATP in human liver was predicted from transport kinetics and protein quantification. We then used MTA to predict the effects of a subset of inhibitors on atorvastatin uptake in vivo. Using a data set of 225 drug-like compounds, 91 OATP inhibitors were identified. In silico models indicated that lipophilicity and polar surface area are key molecular features of OATP inhibition. MTA predictions identified OATP1B1 and OATP1B3 as major determinants of atorvastatin uptake in vivo. The relative contributions to overall hepatic uptake varied with isoform specificities of the inhibitors.

  10. AMCOM Corrosion Program Overview

    DTIC Science & Technology

    2011-08-01

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

  11. Corrosion Maintenance and Experimental Design

    DTIC Science & Technology

    1987-01-01

    drawings, specifications, or other data are used for any purpose other than in connection with a definitely related Government procurement operation...furnished, or in any way supplied the said drawings, specifications, or other data , is not to be re- garded by implication or otherwise as in any manner...in ) evaluation of corrosion inhibitor effectiveness for aircraft rinsing, (2) improvements o AFLC’s Maintenance Data Collection System (MDCS), (3

  12. Fouling and the inhibition of salt corrosion. [hot corrosion of superalloys

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    In an attempt to reduce fouling while retaining the beneficial effects of alkaline earth inhibitors on the hot corrosion of superalloys, the use of both additives and the intermittent application of the inhibitors were evaluated. Additions of alkaline earth compounds to combustion gases containing sodium sulfate were shown to inhibit hot corrosion. However, sulfate deposits can lead to turbine fouling in service. For that reason, dual additives and intermittant inhibitor applications were evaluated to reduce such deposit formation. Silicon in conjunction with varium showed some promise. Total deposition was apparently reduced while the inhibition of hot corrosion by barium was unimpaired. The intermittant application of the inhibitor was found to be more effective and controllable.

  13. Dissolved Organic Matter or Salts Change the Bioavailability Processes and Toxicity of the Nanoscale Tetravalent Lead Corrosion Product PbO2 to Medaka Fish.

    PubMed

    Chiang, Chun-Wei; Ng, Ding-Quan; Lin, Yi-Pin; Chen, Pei-Jen

    2016-10-04

    Nanoscale lead dioxide (nPbO2(s)) is a corrosion product formed from the chlorination of lead-containing plumbing materials. This metal oxide nanoparticle (NP) plays a key role in determining lead pollution in drinking water and receiving water bodies. This study uses nPbO2(s) and medaka fish (Oryzias latipes) as surrogates to investigate the aqueous fate and toxicological risk of metal oxide NPs associated with water matrices. The larvae of medaka were treated with solutions containing nPbO2(s) or Pb(II)aq in different water matrices for 7-14 days to investigate the in vivo toxic effects of NPs. Ionic strength enhanced aggregation and sedimentation of nPbO2(s) in water, leading to increased lead contents in fish bodies. However, the presence of dissolved organic matter in water enhanced particle stability and accelerated the lead dissolution, thus changing the bioavailability processes (bioaccessibility) of particles. Oxidative stress response and neurotoxicity in exposed fish was greater for nPbO2(s) solution with increased salinity than dissolved organic matter. We predict the bioavailability processes and toxicity of nPbO2(s) in medaka from the aqueous particle behavior under environmentally relevant exposure conditions. Our investigation suggests a toxicological risk of metal oxide NP pollution in the aquatic environment.

  14. Enhancement of corrosion resistance of carbon steel by Dioscorea Hispida starch in NaCl

    NASA Astrophysics Data System (ADS)

    Zulhusni, M. D. M.; Othman, N. K.; Lazim, Azwan Mat

    2015-09-01

    Starch is a one of the most abundant natural product in the world and has the potential as corrosion inhibitor replacing harmful synthetic chemical based corrosion inhibitor. This research was aimed to examines the potential of starch extracted from local Malaysian wild yam (Dioscorea hispida), as corrosion inhibitor to carbon steel in NaCl media replicating sea water. By using gravimetric test and analysis, in which the carbon steel specimens were immersed in NaCl media for 24, 48 and 60 hours with the starch as corrosion inhibitor. the corrosion rate (mmpy) and inhibition efficiencies (%) was calculated. The results obtained showed decrease in corrosion rate as higher concentration of starch was employed. The inhibition efficiencies also shows an increasing manner up to 95.97 % as the concentration of the inhibitor increased.

  15. Redox-responsive self-healing for corrosion protection.

    PubMed

    Vimalanandan, Ashokanand; Lv, Li-Ping; Tran, The Hai; Landfester, Katharina; Crespy, Daniel; Rohwerder, Michael

    2013-12-23

    Raspberry-shaped redox-responsive capsules for storing corrosion inhibitors are introduced, targeted to solve the drawbacks of conducting-polymer-based coating systems for corrosion protection. These capsules synthesized via the miniemulsion technique have a remarkable release property upon reduction (onset of corrosion) and cease release upon reoxidation (passivation of the defect). The self-healing capability is demonstrated by application of these capsules as part of a composite coating on zinc.

  16. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    PubMed Central

    Hosseinpour, Saman; Johnson, Magnus

    2017-01-01

    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. PMID:28772781

  17. Corrosion of stainless steel during acetate production

    SciTech Connect

    Qi, J.S.; Lester, G.C.

    1996-07-01

    Corrosion of types 304, 304L, 316, and 316L stainless steel (SS) during the esterification of acetic acid and alcohol or glycol ether was investigated. The catalyst for this reaction, sulfuric acid or para-toluene sulfonic acid (PTSA), was shown to cause more corrosion on reactor equipment than CH{sub 3}COOH under the process conditions commonly practiced in industry. The corrosive action of the catalyst occurred only in the presence of water. Thus, for the batch processes, corrosion occurred mostly during the initial stage of esterification, where water produced by the reaction created an aqueous environment. After water was distilled off, the corrosion rate declined to a negligible value. The corrosion inhibitor copper sulfate, often used in industrial acetate processes, was found to work well for a low-temperature process (< 95 C) such as in production of butyl acetate, but it accelerated corrosion in the glycol ether acetate processes where temperatures were > 108 C. Process conditions that imparted low corrosion rates were determined.

  18. Chemical Industry Corrosion Management

    SciTech Connect

    2003-02-01

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

  19. Coatings and methods for corrosion detection and/or reduction

    NASA Technical Reports Server (NTRS)

    Calle, Luz M. (Inventor); Li, Wenyan (Inventor)

    2010-01-01

    Coatings and methods are provided. An embodiment of the coating includes microcapsules that contain at least one of a corrosion inhibitor, a film-forming compound, and an indicator. The microcapsules are dispersed in a coating vehicle. A shell of each microcapsule breaks down in the presence of an alkaline condition, resulting from corrosion.

  20. Synthetic seawater as stress-corrosion test medium

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    Seawater minimizes pitting corrosion of aluminum-alloy test samples. Of three corrosion-inhibiting methods evaluated using (a) chromate inhibitors in saltwater, (b) surface treating sample via anodizing or alodine treatment, and (c) synthetic seawater, synthetic seawater was most effective test medium, since it is more uniform than fresh seawater.

  1. Synthetic seawater as stress-corrosion test medium

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    Seawater minimizes pitting corrosion of aluminum-alloy test samples. Of three corrosion-inhibiting methods evaluated using (a) chromate inhibitors in saltwater, (b) surface treating sample via anodizing or alodine treatment, and (c) synthetic seawater, synthetic seawater was most effective test medium, since it is more uniform than fresh seawater.

  2. Corrosion Damage Functions

    SciTech Connect

    Jones, Russell H.

    2002-11-30

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

  3. Influence of Ce3+ doping on molecular organization of Si-based organic/inorganic sol-gel layers for corrosion protection

    NASA Astrophysics Data System (ADS)

    Fedel, Michele; Callone, Emanuela; Fabbian, Matias; Deflorian, Flavio; Dirè, Sandra

    2017-08-01

    In this work, organosilane-derived sol-gel films containing different amounts of cerium ions applied on AA 1050 were investigated. The sol-gel coatings were prepared from 3-glycidoxypropyltrimethoxysilane (GPTMS) and methyltriethoxysilane (MTES) mixtures with the addition of cerium nitrate in order to achieve different concentrations of Ce ions (from 10-5 M to 10-2 M). The effect of the cerium load on the structure of the cured sol-gel films was investigated by means of solid state NMR and FT-IR spectroscopy. The corrosion protection properties of the different sol-gel layers were investigated mainly by means potentiodynamic curves and electrochemical impedance spectroscopy (EIS). FT-IR and solid state NMR suggested a significant influence of the Ce cations on the network structure: not only the degree of condensation decreases with Ce addition but also the structural modification of the silsesquioxane network is observed with preferential formation of ladder-like species for low Ce3+ content and cages predominance for Ce/Si molar ratio greater than 0.039, i.e. [Ce3+] = 1·10-4 M. Electrochemical tests revealed that the effect of Ce ions on the structure of the coatings does not lead to remarkable changes in the barrier properties. Moreover, it was found that the Ce ions seems to be present in the cured films and are able to migrate towards the metal/coating interface thus providing a stabilization of the metal interface.

  4. Corrosion inhibition of mild steel in 1 M hydrochloric acid by 2,5-bis(2-aminophenyl)-1,3,4-oxadiazole

    SciTech Connect

    Bentiss, F.; Lagrenee, M.; Traisnel, M.; Hornez, J.C.

    1999-10-01

    The inhibition effect of a new class of organic inhibitors (e.g., 2,5-bis(2-aminophenyl)-1,3,4-oxadiazole [2-APOX]) on the corrosion of mild steel in molar hydrochloric acid (HCl) was investigated. The inhibitor was synthesized and its inhibiting action on the corrosion was studied through weight loss and various electrochemical techniques. Potentiodynamic polarization studies clearly revealed the fact that 2-APOX is a mixed-type inhibitor. Changes in impedance parameters (charge-transfer resistance [R{sub t}] and double-layer capacitance [C{sub dl}]) were indicative of adsorption of 2-APOX on the metal surface, leading to the formation of a protective film that grew with increasing exposure time. The 2-APOX appeared to function through the general adsorption mode following the Langmuir adsorption isotherm model. Effect of temperature on the corrosion behavior of mild steel in 1 M NCl with addition of 80 mg/L of 2-APOX was studied in the temperature range from 25 C to 60 C. The associated activation corrosion and free adsorption energies were determined. This inhibitor is considered a noncytotoxic substance.

  5. CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

    SciTech Connect

    Subramanian, K; Kerry Dunn, K; Joseph Murphy, J

    2008-07-18

    Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding that was induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species used in the construction of the packaging, followed by polyvinyl acetate (PVAc) glue. Fiberboard material, also used in the construction of the packaging induced corrosion to a much lesser extent than the PVAc glue and RTV sealant, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water. In light of these corrosion mechanisms, the lead shielding was sheathed in a stainless steel liner to mitigate against corrosion.

  6. Post-marketing surveillance of ischaemic optic neuropathy in male veterans co-prescribed phosphodiesterase-5 inhibitors with organic nitrates or alpha-blockers.

    PubMed

    French, Dustin D; Margo, Curtis E

    2008-01-01

    The cause of nonarteritic anterior ischaemic optic neuropathy (ION) is unknown, although assumed to be related to transient vascular insufficiency of the optic nerve head. Because the interaction of phosphodiesterase-5 (PDE-5) inhibitors with either an organic nitrate or alpha-blocker may theoretically increase the risk of ION, we conducted a screening study to determine if such a risk might exist. Retrospective cohort study of male veterans with ION and possible ION. The national Veterans Health Administration (VHA) clinical database was cross-referenced (linked) with the VHA pharmacy database looking for specific drug combinations. Compared with no use, the relative risk (RR) of ION and possible ION for men prescribed both PDE-5 inhibitor and organic nitrate was 1.41 (95% CI 0.85, 2.33). Similarly, the RR of ION and possible ION with concurrent prescription of PDE-5 inhibitor and alpha-blocker was 1.21 (95% CI 1.01, 1.44). When risk was measured against use of a PDE-5 inhibitor alone, the RR was 1.29 (95% CI 0.78, 2.16) for PDE-5 inhibitor and organic nitrate and 1.12 (95% CI 0.92, 1.35) for PDE-5 inhibitor and alpha-blocker. We linked two large national databases to screen for a potentially important drug-drug-disease interaction. There was no increase in risk of ION and possible ION in men dispensed a PDE-5 inhibitor with either organic nitrates or an alpha-blocker compared with men dispensed PDE-5 inhibitor alone. An incidental observation that a substantial number of men were prescribed both an organic nitrate and a PDE-5 inhibitor within a single dispensing period raises concerns over non-ocular safety issues. The wisdom of co-dispensing medications that are contraindicated may deserve a broader audience.

  7. Novel Inhibitors of Human Organic Cation/Carnitine Transporter (hOCTN2) via Computational Modeling and In Vitro Testing

    PubMed Central

    Diao, Lei; Ekins, Sean; Polli, James E.

    2010-01-01

    Purpose The objective was to elucidate the inhibition requirements of the human Organic Cation/Carnitine Transporter (hOCTN2). Methods Twenty-seven drugs were screened initially for their potential to inhibit uptake of L-carnitine into a stably transfected hOCTN2-MDCK cell monolayer. A HipHop common features pharmacophore was developed and used to search a drug database. Fifty-three drugs, including some not predicted to be inhibitors, were selected and screened in vitro. Results A common features pharmacophore was derived from initial screening data and consisted of three hydrophobic features and a positive ionizable feature. Among the 33 tested drugs that were predicted to map to the pharmacophore, 27 inhibited hOCTN2 in vitro (40% or less L-carnitine uptake from 2.5μM L-carnitine solution in presence of 500 μM drug, compared to L-carnitine uptake without drug present). Hence, the pharmacophore accurately prioritized compounds for testing. Ki measurements showed low micromolar inhibitors belonged to diverse therapeutic classes of drugs, including many not previously known to inhibit hOCTN2. Compounds were more likely to cause rhabdomyolysis if the Cmax/Ki ratio was higher than 0.0025. Conclusion A combined pharmacophore and in vitro approach found new, structurally diverse inhibitors for hOCTN2 that may possibly cause clinical significant toxicity such as rhabdomyolysis. PMID:19437106

  8. Zero discharge organic coatings, powder paint - UV curable paint - E-coat. Volume 1. Final report, June 1993-June 1995

    SciTech Connect

    Leal, J.; Martin, D.R.; Spadafora, S.J.; Eng, A.T.; Stark, H.

    1995-06-01

    Zero Discharge Organic Coatings project developed powder paint, Ultraviolet (UV) curable paint, and electro- coating (E-coat) paint for military Applications. These technologies offer potential for high performance coatings with little or no volatile organic compound (VOC) emissions or hazardous waste generation. The ZDOC project focused on formulating non-toxic corrosion inhibitors into these coating technologies, and the applications development of powder coatings. Non-toxic replacements for traditional lead and chromate inhibitors were selected based on a previous NAWCADWAR investigation. Once incorporated, the performance of the coatings with and without inhibitors was compared. Also, the protective mechanisms of these inhibitors were studied. The applications development for powder coatings analyzed technologies to allow powder coating of non-conductive substrates and evaluated the use of IR energy to cure powder coatings. Inhibitors were successfully incorporated into electrocoatings and powder coatings, however corrosion performance results varied with coating formulation.

  9. Corrosion inhibition in lithium bromide absorption fluid for advanced and current absorption cycle machines

    SciTech Connect

    Verma, S.K.; Mekhjian, M.S.; Sandor, G.R.; Nakada, N.

    1999-07-01

    This paper presents the results of a novel corrosion inhibitor that exhibits improved protection of carbon steel over the inhibitors currently in practice. This inhibitor, formulated in 65 wt% lithium bromide solution, offers excellent corrosion protection to carbon steel. Corrosion rates were determined using autoclave coupon testing. The corrosion rate in the 300 F to 450 F range was found to be low (1 to 4 mils per year), and the product also showed very low hydrogen generation (0.03 mg/in.{sup 2} of carbon steel per week). The metal was protected with a stable and adherent film.

  10. Effects of organic nitrification inhibitors on methane and nitrous oxide emission from tropical rice paddy

    NASA Astrophysics Data System (ADS)

    Datta, A.; Adhya, T. K.

    2014-08-01

    We have studied the effects of application of different nitrification inhibitors on methane (CH4) and nitrous oxide (N2O) emissions from rice paddy and associated soil chemical and biological dynamics during wet and dry seasons of rice crop in a tropical climate of eastern India. The experiment consisted of four treatments viz. (i) Prilled urea amended control (ii) urea + Dicyandiamide (DCD), (iii) urea + Nimin and (iv) urea + Karanjin. CH4 emission was significantly higher from the DCD (372.36 kg ha-1) and Karanjin (153.07 kg ha-1) applied plots during the wet and dry season, respectively. N2O emission was significantly inhibited in the Nimin applied plots during both seasons (69% and 85% over control during wet season and dry season respectively). CH4 and N2O emissions per Mg of rice grain yield were lowest from the Nimin applied plots during both seasons. Global warming potential (GWP) of the plot treated with DCD (13.93) was significantly higher during the experimental period. CH4 production potential was significantly higher from the nitrification inhibitor applied plots compared to control. While, CH4 oxidation potential followed the order; urea + Nimin > urea + Karanjin > urea + DCD > control. Application of Nimin significantly increased the methanotrophic bacterial population in the soil during the maximum tillering to flowering stage and may be attributed to low CH4 emission from the plots. Denitrification enzyme activity (DEA) of the soil was significantly low from the Nimin and Karanjin applied plots. Results suggest that apart from being potent nitrification inhibitors, Nimin and Karanjin also have the potential to reduce the denitrification activity in the soil. This in turn, would reduce N2O emission from flooded paddy where both nitrification and denitrification processes causes N2O emission.

  11. Proteins of circularly permuted sequence present within the same organism: The major serine proteinase inhibitor from Capsicum annuum seeds

    PubMed Central

    Antcheva, Nikolinka; Pintar, Alessandro; Patthy, András; Simoncsits, András; Barta, Endre; Tchorbanov, Bojidar; Pongor, Sándor

    2001-01-01

    The major serine proteinase inhibitor from bell pepper (Capsicum annuum, paprika) seeds was isolated, characterized, and sequenced, and its disulfide bond topology was determined. PSI-1.2 is a 52-amino-acid-long, cysteine-rich polypeptide that inhibits both trypsin (Ki = 4.6 × 10−9 M) and chymotrypsin (Ki = 1.1 × 10−8 M) and is a circularly permuted member of the potato type II inhibitor family. Mature proteins of this family are produced from precursor proteins containing two to eight repeat units that are proteolytically cleaved within, rather than between, the repeats. In contrast, PSI-1.2 corresponds to a complete repeat that was predicted as the putative ancestral protein of the potato type II family. To our knowledge, this is the first case in which two proteins related to each other by circular permutation are shown to exist in the same organism and are expressed within the same organ. PSI-1.2 is not derived from any of the known precursors, and it contains a unique amphiphilic segment in one of its loops. A systematic comparison of the related precursor repeat-sequences reveals common evolutionary patterns that are in agreement with the ancestral gene-duplication hypothesis. PMID:11604534

  12. Microwave assisted organic synthesis (MAOS) of small molecules as potential HIV-1 integrase inhibitors.

    PubMed

    Ferro, Stefania; Grazia, Sara De; De Luca, Laura; Gitto, Rosaria; Faliti, Caterina Elisa; Debyzer, Zeger; Chimirri, Alba

    2011-08-11

    Integrase (IN) represents a clinically validated target for the development of antivirals against human immunodeficiency virus (HIV). In recent years our research group has been engaged in the stucture-function study of this enzyme and in the development of some three-dimensional pharmacophore models which have led to the identification of a large series of potent HIV-1 integrase strand-transfer inhibitors (INSTIs) bearing an indole core. To gain a better understanding of the structure-activity relationships (SARs), herein we report the design and microwave-assisted synthesis of a novel series of 1-H-benzylindole derivatives.

  13. Self-organization induced by the differential flow of activator and inhibitor

    NASA Astrophysics Data System (ADS)

    Rovinsky, Arkady B.; Menzinger, Michael

    1993-02-01

    We have experimentally verified the prediction that a homogeneous steady state of an activator-inhibitor system can be destabilized by a differential flow of the key species, rather than by their differential diffusivity for Turing instability. Traveling waves are generated by a flow of Belousov-Zhabotinsky reactants through a tube containing ferroin immobilized on a cation exchanger. Without flow the system resides in a homogeneous steady state. This mechanism of spatiotemporal pattern formation avoids the restrictions of the Turing instability on the diffusion coefficients and can thus be expected to operate in a larger class of chemical, physical, and biological systems.

  14. A Balance between Secreted Inhibitors and Edge Sensing Controls Gastruloid Self-Organization.

    PubMed

    Etoc, Fred; Metzger, Jakob; Ruzo, Albert; Kirst, Christoph; Yoney, Anna; Ozair, M Zeeshan; Brivanlou, Ali H; Siggia, Eric D

    2016-11-07

    The earliest aspects of human embryogenesis remain mysterious. To model patterning events in the human embryo, we used colonies of human embryonic stem cells (hESCs) grown on micropatterned substrate and differentiated with BMP4. These gastruloids recapitulate the embryonic arrangement of the mammalian germ layers and provide an assay to assess the structural and signaling mechanisms patterning the human gastrula. Structurally, high-density hESCs localize their receptors to transforming growth factor β at their lateral side in the center of the colony while maintaining apical localization of receptors at the edge. This relocalization insulates cells at the center from apically applied ligands while maintaining response to basally presented ones. In addition, BMP4 directly induces the expression of its own inhibitor, NOGGIN, generating a reaction-diffusion mechanism that underlies patterning. We develop a quantitative model that integrates edge sensing and inhibitors to predict human fate positioning in gastruloids and, potentially, the human embryo. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. The effect of modifying rooting depths and nitrification inhibitors on nutrient uptake from organic biogas residues in maize

    NASA Astrophysics Data System (ADS)

    Dietrich, Charlotte C.; Koller, Robert; Nagel, Kerstin A.; Schickling, Anke; Schrey, Silvia D.; Jablonowski, Nicolai D.

    2017-04-01

    Optimizing the application of and nutrient uptake from organic nutrient sources, such as the nutrient-rich residues ("digestates") from the biogas industry, is becoming a viable option in remediating fertility on previously unsuitable soils for agricultural utilization. Proposedly, concurrent changes in root system architecture and functioning could also serve as the basis of future phytomining approaches. Herein, we evaluate the effect of spatial nutrient availability and nitrification on maize root architecture and nutrient uptake. We test these effects by applying maize-based digestate at a rate of 170 kg/ha in layers of varying depths (10, 25 and 40 cm) and through either the presence or absence of nitrification inhibitors. In order to regularly monitor above- and below-ground plant biomass production, we used the noninvasive phenotyping platform, GROWSCREEN-Rhizo at the Forschungszentrum Jülich, using rhizotrons (Nagel et al., 2012). Measured parameters included projected plant height and leaf area, as well as root length and spatial distribution. Additionally, root diameters were quantified after the destructive harvest, 21 days after sowing (DAS). Spatial nutrient availability significantly affected root system architecture, as for example root system size -the area occupied by roots- increased alongside nutrient layer depths. Fertilization also positively affected root length density (RLD). Within fertilized layers, the presence of nitrification inhibitors increased RLD by up to 30% and was most pronounced in the fine root biomass fraction (0.1 to 0.5mm). Generally, nitrification inhibitors promoted early plant growth by up to 45% across treatments. However, their effect varied in dependence of layer depths, leading to a time-delayed response in deeper layers, accounting for plants having to grow significantly longer roots in order to reach fertilized substrate. Nitrification inhibitors also initiated the comparatively early on-set of growth differences in

  16. Experiment Study on Corrosion Control Using Coking Wastewater as Circulating Cooling Water

    NASA Astrophysics Data System (ADS)

    Zhang, Huanzhen; Dong, Changqing; Bian, Lei; Zhao, Qian

    The coking wastewater drainage will bring severe water environmental pollution, so it is necessary to change the coking wastewater into resource. The reuse of pre-treated coking wastewater as make-up water for circulating cooling system is an important way. To prevent the circulating cooling system corrosion, the characteristic and the corrosion control technology and the effect of the classic corrosion inhibitors in the circulating cooling water system were studied by static experiment and dynamic experiment based on water quality stabilization theory. The results indicate that the corrosion in circulating cooling system is mainly spot corrosion caused by pollutants in coking wastewater, and the corrosion inhibition technology on the model of precipitated membrane based on phosphor series should be preferred. The mixed corrosion inhibitors HEDP and Zn 2+ optimally selected by experiment can form a firm corrosion inhibition membrane on heat transfer surface, and the corrosion inhibition rate could reach 85.6%. The corrosion rate of common carbon steel is 0.105 mm/a, which could satisfy the criterion of > Design criterion of the industrial circulating cooling water treatment > (GB 50050-95). The practical application to the circulating cooling system shows that the mixed corrosion inhibitors HEDP and Zn 2+ can control the corrosion in the system economically when the concentration multiple is 2-2.2, which opens up a feasible way for changing the coking wastewater into resource.

  17. Calcineurin inhibitor-sparing regimens in solid organ transplantation: focus on improving renal function and nephrotoxicity.

    PubMed

    Flechner, Stuart M; Kobashigawa, Jon; Klintmalm, Goran

    2008-01-01

    The calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, have had a revolutionary effect on the overall success of renal transplantation through reduction in early immunologic injury and acute rejection rates. However, the CNIs have a significant adverse impact on renal function and cardiovascular disease, and extended long-term graft survival has not been achieved. The recognition of these effects sparked interest in CNI-sparing strategies. Strategies to limit CNI exposure include CNI minimization, avoidance, and withdrawal. We sought to review the impact of CNI-sparing strategies in kidney, liver, and heart transplantation. A PubMed search 1966 to August 2006 was conducted to identify relevant research articles, and the references of these articles as well as the authors' personal files were reviewed. Calcineurin inhibitor minimization using mycophenolate mofetil or sirolimus may be associated with a modest increase in creatinine clearance (CrCl) and a decrease in serum creatinine (SCr) in the short term. Despite improvement in CrCl or SCr, CNI nephrotoxicity and chronic allograft nephrotoxicity are progressive over time when CNI exposure is maintained. In kidney transplantation, the tubulo-interstitial and glomerular damage are irreversible. Mycophenolate mofetil may improve renal outcomes during CNI minimization more than sirolimus, and antibody induction may be effective to limit CNI exposure, but longer-term follow-up data are required. Use of sirolimus with mycophenolate mofetil or azathioprine to avoid CNI exposure de novo has improved glomerular filtration rate for at least two yr in most studies in kidney transplantation; however, experience is limited in liver and heart transplantation, and reports of delayed graft function and wound healing with sirolimus may have dampened enthusiasm for de novo use. Late CNI withdrawal has achieved variable results, possibly because withdrawal was attempted after the kidney damage was too extensive. Early CNI

  18. A time-release technique for corrosion prevention

    SciTech Connect

    Dry, C.M.; Corsaw, M.J.T.

    1998-08-01

    Researchers at the University of Illinois have developed an anti-corrosion system that is activated automatically where and when it is needed. Porous fibers are filled with calcium nitrite and coated with a salt-sensitive substance to control the response. The release of the corrosion inhibitor chemical is at the portion of the reinforcing bar in danger of corrosion when conditions would allow corrosion to initiate. In a series of tests with concrete samples containing either no protection or the conventional freely mixed calcium nitrite, this system performed well in that it delayed the onset of corrosion by at least three weeks in the laboratory specimens and reduced the amount of total corrosion by more than half.

  19. Internal Corrosion and Deposition Control

    EPA Science Inventory

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

  20. Internal Corrosion and Deposition Control

    EPA Science Inventory

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

  1. Bisindolylmaleimide protein-kinase-C inhibitors delay the decline in DNA synthesis in mouse hair follicle organ cultures.

    PubMed

    Harmon, C S; Nevins, T D; Ducote, J; Lutz, D

    1997-01-01

    We have used a series of bisindolylmaleimide selective protein-kinase C (PKC) inhibitors to investigate the role of this enzyme in the regulation of cell proliferation in mouse hair follicle organ cultures. Mouse whisker follicles were isolated by microdissection, and rates of DNA synthesis during culture were determined from 3H-thymidine incorporation. The bisindolylmaleimides Ro 31-7549, Ro 31-8161, Ro 31-8425 and Ro 31-8830 inhibit isolated brain PKC with IC50 values of 8-80 nM, are > 60-fold less potent against protein kinase A, and inhibit PKC-mediated protein phosphorylation in platelets with IC50 values in the range 0.25-4.4 microM. These PKC inhibitors were found to increase levels of mouse hair follicle DNA synthesis, with EC50 values in the range 1-4 microM and maximal levels in the range 151-197% of control. Ro 31-7549 had an IC50 value 50-fold lower than that of minoxidil, while the maximal level of DNA synthesis for the PKC inhibitor was 86% higher. Incubation of mouse hair follicles with Ro 31-7549 resulted in a delay of approximately 24 h in the onset of decline in follicular DNA synthesis rates. Ro 31-6045 and Ro 31-7208, bisindolylmaleimides without activity in the platelet PKC assay, did not affect mouse hair follicle DNA synthesis rates. Taken together, these findings show that PKC mediates, at least in part, the rapid loss of proliferative activity that occurs in mouse whisker follicles in culture, and provide further evidence that PKC plays a role as a negative proliferative signal in hair follicles.

  2. Factors affecting the corrosivity of pulping liquors

    NASA Astrophysics Data System (ADS)

    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.

  3. Affinity capture of a mammalian DNA polymerase beta by inhibitors immobilized to resins used in solid-phase organic synthesis.

    PubMed

    Kuramochi, Kouji; Haruyama, Tetsuya; Takeuchi, Ryo; Sunoki, Takashi; Watanabe, Madoka; Oshige, Masahiko; Kobayashi, Susumu; Sakaguchi, Kengo; Sugawara, Fumio

    2005-01-01

    The application of resins normally used in solid-phase organic synthesis to the affinity capture of a mammalian DNA polymerase beta (pol beta) is reported. Lithocholic acid (LCA), an inhibitor of pol beta, was immobilized on various solid supports, and the batch affinity purification of pol beta from a mixture of proteins using these LCA-immobilized resins was examined. Of the resins tested, TentaGel was the most effective at purifying pol beta and at resisting nonspecific absorption of proteins. The immobilized LCA recognized pol beta specifically, which resulted in pol beta binding to the resin. Using the LCA-immobilized resin, it was possible to purify pol beta from a mixture of proteins. Furthermore, it was possible to concentrate pol beta from a crude nuclear extract of human T lymphoma Molt4 cells. To facilitate the immobilization of compounds on TentaGel resins, we also designed and prepared photoaffinity beads containing a photoreactive group at the free termini of the TentaGel resin. The pol beta inhibitors LCA, C18-beta-SQDG, and epolactaene were immobilized on the photoaffinity beads by photoreaction. The batch affinity purification of pol beta from a protein mixture could be also achieved with these beads.

  4. Self-organizing molecular field analysis on pregnane derivatives as human steroidal 5alpha-reductase inhibitors.

    PubMed

    Aggarwal, Saurabh; Thareja, Suresh; Bhardwaj, Tilak Raj; Kumar, Manoj

    2010-06-01

    Normal growth and development of human prostate is regulated by the androgens which balances cell proliferation and apoptosis. Testosterone (T) and dihydrotestosterone (DHT) are the two key androgens that stimulate most of the androgen action in prostate. Testosterone is converted to DHT by the membrane bound NADPH-dependent 5alpha-reductase enzyme. As a consequence of the important observation that progesterone and deoxycortisone inhibits the synthesis of DHT by competing with 4-en-3-one function of the testosterone for the 5alpha-reductase enzyme a number of pregnane derivatives were synthesized and have been reported as inhibitors of human 5alpha-reductase enzyme. Due to lack of information on the crystal structure of human 5alpha-reductase, ligand-based 3D-QSAR study has been performed on pregnane derivatives using self-organizing molecular field analysis (SOMFA) for rationalizing the molecular properties and human 5alpha-reductase inhibitory activities. The statistical results having good cross-validated r(cv)(2) (0.881), non-cross-validated r(2) (0.893) and F-test value (175.527), showed satisfied predictive ability r(pred)(2) (0.777). Analysis of SOMFA models through electrostatic and shape grids provide useful information for the design and optimization of steroidal structure as novel human 5alpha-reductase inhibitors.

  5. Inhibitive effects of palm kernel oil on carbon steel corrosion by alkaline solution

    NASA Astrophysics Data System (ADS)

    Zulkafli, M. Y.; Othman, N. K.; Lazim, A. M.; Jalar, A.

    2013-11-01

    The behavior of carbon steel SAE 1045 in 1 M NaOH solution containing different concentrations of palm kernel oil (PKO) has been studied by weight loss and polarization measurement. Results showed that the corrosion of carbon steel in NaOH solution was considerably reduced in presence of such inhibitors. The inhibition efficiency increases when concentration of inhibitor increase. Maximum inhibition efficiency (≈ 96.67%) is obtained at PKO concentration 8 v/v %. This result revealed that palm kernel oil can act as a corrosion inhibitor in an alkaline medium. Corrosion rates of carbon steel decrease as the concentration of inhibitor is increased.

  6. Hybrid nanostructured coatings for corrosion protection of base metals: a sustainability perspective

    NASA Astrophysics Data System (ADS)

    Dennis, Robert V.; Patil, Vikas; Andrews, Justin L.; Aldinger, Jeffrey P.; Yadav, Ganapati D.; Banerjee, Sarbajit

    2015-03-01

    In this topical review article, we attempt to capture recent advances in the development of sustainable hybrid nanocomposite coatings for the corrosion inhibition of structural metals. Spurred primarily by the urgent imperative of replacing hexavalent chromium but also driven by concerns regarding the environmental impact of organic solvents, materials criticality considerations, the need to maintain structural integrity and function under extreme environments, and a renewed impetus towards lightweighting, the design of new coating concepts has seen an explosion of activity. We discuss varying modes of corrosion inhibition and the drive towards multicomponent nanostructured coatings that synergistically unite multiple modes of corrosion inhibition within a single coating system. Nanocomposite coatings in which nanoparticles of one phase are dispersed within a continuous phase, usually a polymeric matrix, provide a modular design approach to multifunctional coatings provided fundamental challenges such as dispersion and compatibility can be resolved. By dint of their high surface-to-volume ratios, the incorporation of nanoparticles profoundly modifies the adjacent polymeric matrix, giving rise to an ‘interphase’ region with modified properties, at relatively low filler loadings. The implications of incorporating metallic, porous metal oxide, and carbon nanomaterials (graphene and carbon nanotubes) within polymeric matrices are explored with an emphasis on active corrosion inhibition. The availability of high-quality nanoparticles that are either electroactive (e.g., metals, graphene, carbon nanotubes, etc.) or are capable of serving as reservoirs for active corrosion inhibitors (e.g., porous silicon oxide, layered double hydroxides, halloysite) provides unprecedented functionality and opportunities for multifunctional coatings. The review emphasizes mechanistic considerations where these have been elucidated with a view towards developing systematic design

  7. Bringing research into a first semester organic chemistry laboratory with the multistep synthesis of carbohydrate-based HIV inhibitor mimics.

    PubMed

    Pontrello, Jason K

    2015-01-01

    Benefits of incorporating research experiences into laboratory courses have been well documented, yet examples of research projects designed for the first semester introductory organic chemistry lab course are extremely rare. To address this deficiency, a Carbohydrate-Based human immunodeficiency virus (HIV) Inhibitor project consisting of a synthetic scheme of four reactions was developed for and implemented in the first semester organic lab. Students carried out the synthetic reactions during the last 6 of 10 total labs in the course, generating carbohydrate-based dimeric target molecules modeled after published dimers with application in HIV therapy. The project was designed to provide a research experience through use of literature procedures for reactions performed, exploration of variation in linker length in the target structure, and synthesis of compounds not previously reported in the scientific literature. Project assessment revealed strong student support, indicating enhanced engagement and interest in the course as a direct result of the use of scientific literature and the applications of the synthesized carbohydrate-based molecules. Regardless of discussed challenges in designing a research project for the first semester lab course, the finding from data analysis that a project implemented in the first semester lab had significantly greater student impact than a second semester project should provide motivation for development of additional research projects for a first semester organic course.

  8. Microbiologically Influenced Corrosion of Pilings

    DTIC Science & Technology

    2014-03-04

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

  9. End-organ protection in hypertension by the novel and selective Rho-kinase inhibitor, SAR407899

    PubMed Central

    Löhn, Matthias; Plettenburg, Oliver; Kannt, Aimo; Kohlmann, Markus; Hofmeister, Armin; Kadereit, Dieter; Monecke, Peter; Schiffer, Alexander; Schulte, Anke; Ruetten, Hartmut; Ivashchenko, Yuri

    2015-01-01

    AIM: To compare the therapeutic efficacy of SAR407899 with the current standard treatment for hypertension [an angiotensin converting enzyme (ACE)-inhibitor and a calcium channel blocker] and compare the frequency and severity of the hypertension-related end-organ damage. METHODS: Long-term pharmacological characte-rization of SAR407899 has been performed in two animal models of hypertension, of which one is sensitive to ACE-inhibition (LNAME) and the other is insensitive [deoxycorticosterone acetate (DOCA)]. SAR407899 efficiently lowered high blood pressure and significantly reduced late-stage end organ damage as indicated by improved heart, kidney and endothelial function and reduced heart and kidney fibrosis in both models of chronic hypertension. RESULTS: Long term treatment with SAR407899 has been well tolerated and dose-dependently reduced elevated blood pressure in both models with no signs of tachyphylaxia. Blood pressure lowering effects and protective effects on hypertension related end organ damage of SAR407899 were superior to ramipril and amlodipine in the DOCA rat. Typical end-organ damage was significantly reduced in the SAR407899-treated animals. Chronic administration of SAR407899 significantly reduced albuminuria in both models. The beneficial effect of SAR407899 was associated with a reduction in leukocyte/macrophage tissue infiltration. The overall protective effect of SAR407899 was superior or comparable to that of ACE-inhibition or calcium channel blockade. Chronic application of SAR407899 protects against hypertension and hypertension-induced end organ damage, regardless of the pathophysiological mechanism of hypertension. CONCLUSION: Rho-kinases-inhibition by the SAR407899 represents a new therapeutic option for the treatment of hypertension and its complications. PMID:25632317

  10. 17-DMAG, an HSP90 Inhibitor, Ameliorates Multiple Organ Dysfunction Syndrome via Induction of HSP70 in Endotoxemic Rats

    PubMed Central

    Wang, Yi-Li; Shen, Hsin-Hsueh; Cheng, Pao-Yun; Chu, Yen-Ju; Hwang, Hwong-Ru; Lam, Kwok-Keung; Lee, Yen-Mei

    2016-01-01

    Sepsis is a systemic inflammatory disorder, accompanied with elevated oxidative stress, leading to multiple organ dysfunction syndrome (MODS), and disseminated intravascular coagulation. 17-Dimethylaminoethylamino- 17-demethoxygeldanamycin (17-DMAG), a heat shock protein (HSP) 90 inhibitor, has been reported to possess anti-inflammatory effects. In this study, the beneficial effects of 17-DMAG on lipopolysaccharide (LPS) induced MODS and DIC was evaluated in anesthetized rats. 17-DMAG (5 mg/kg, i.p.) was significantly increased survival rate, and prevented hypotension in LPS (30 mg/kg i.v. infused for 4 h) induced endotoxemia. The elevated levels of alanine aminotransferase (ALT), creatine phosphokinase (CPK), lactate dehydrogenase, creatinine, nitric oxide (NO) metabolites, IL-6, and TNF-α in LPS-exposed rat plasma were significantly reduced by 17-DMAG. Moreover, 17-DMAG suppressed LPS-induced superoxide anion production and caspase 3 activation in heart tissues. LPS induced the prolongation of prothrombin time, and a pronounced decrease in platelet count, which were improved by 17-DMAG. 17-DMAG markedly induced HSP70 and heme oxygenase (HO)-1, and suppressed inducible nitric oxide synthase (iNOS) and phosphorylated NF-κB p65 protein expression in organs 6 h after LPS initiation. Pretreatment with high dose of quercetin (300 mg/kg, i.p.), as an HSP70 inhibitor, reversed the beneficial effects of 17-DMAG on survival rate, plasma levels of ALT, CPK, creatinine, IL-6, and NO metabolites, iNOS induction, and caspase-3 activation in LPS-treated rats. In conclusion, 17-DMAG possesses the anti-inflammatory and antioxidant effects that were proved through LPS-induced acute inflammation, which is associated with induction of HSP70 and HO-1, leading to prevent MODS in sepsis. PMID:27224288

  11. Clinical CYP3A inhibitor alternatives to ketoconazole, clarithromycin and itraconazole, are not transported into the liver by hepatic organic anion transporting polypeptides and organic cation transporter 1.

    PubMed

    Higgins, J William; Ke, Alice B; Zamek-Gliszczynski, Maciej J

    2014-11-01

    Ketoconazole is no longer available for clinical determination of worst-case victim drug-drug interaction (DDI) potential for cytochrome P450 3A (CYP3A)-substrate drugs; clarithromycin and itraconazole are the proposed replacements. Ketoconazole DDIs are described by unbound systemic exposures due to absence of carrier-facilitated hepatic uptake, but this aspect of clarithromycin and itraconazole disposition has not been investigated. At present, transport of clarithromycin, itraconazole, and hydroxyitraconazole by hepatic organic anion transporting polypeptides (OATPs) and organic cation transporter 1 (OCT1) was examined in vitro and in vivo. As for ketoconazole, uptake of clarithromycin, itraconazole, and hydroxyitraconazole into OATP1B1, OATP1B3, OATP2B1, and OCT1 expressing human embryonic kidney 293 (HEK293) cells was not greater than in vector controls. Uptake into these HEK293 cells and human hepatocytes was not impaired by the prototypical OATP, OCT, and sodium/taurocholate cotransporting polypeptide inhibitors bromosulfophthalein, imipramine, and taurocholate, respectively. In contrast, uptake of the positive controls, atorvastatin for OATPs and metformin for OCT1, was significantly enhanced by relevant transporter expression, and uptake into both these HEK293 cells and human hepatocytes was significantly impaired by prototypical inhibitors. In Oatp1a/1b gene cluster knockout mice, which lack the major hepatic Oatps, and in Oct1/2 knockout mice, ketoconazole, clarithromycin, itraconazole, and hydroxyitraconazole oral exposure was not increased, and the liver-to-blood partition coefficient (Kp) was not decreased. By contrast relative to wild-type mice, in Oatp1a/1b- and Oct1/2-knockout mice, atorvastatin and metformin oral exposure was significantly increased, and liver Kp was significantly decreased. The present studies provide in vitro and in vivo evidence that, like ketoconazole, clarithromycin, itraconazole, and hydroxyitraconazole are not transported

  12. Benzimidazole ligands in the corrosion inhibition for carbon steel in acid medium: DFT study of its interaction on Fe30 surface

    NASA Astrophysics Data System (ADS)

    Garcia-Ochoa, E.; Guzmán-Jiménez, S. J.; Hernández, J. Guadalupe; Pandiyan, Thangarasu; Vásquez-Pérez, José M.; Cruz-Borbolla, Julián

    2016-09-01

    The corrosion inhibition of N,N‧-bis(benzimidazole-2-yl-methyl)amine (L1) and N, N‧-bis(benzimidazole-2-yl-methyl)hydroxyethylamine (L2) was analyzed by electrochemical and theoretical methods. The data show that ligands form an adsorption layer over an iron surface, obeying the Langmuir isotherm (Δ Gads° of -32.96 kJ mol-1); the value are higher than -20 kJ mol-1 but less than -40 kJ mol-1, belonging to a conversion stage of physical adsorption to chemical adsorption or a comprehensive adsorption. This is consistent with fractal dimension of the electrode surface, estimated by an impedance depression angle of a semicircle that the surface is homogeneously covered by the formation of an inhibitor film. Furthermore, the electronic parameters of the ligands were analyzed by DFT, showing that L1 and L2 possesses corrosion inhibition properties that give up its p orbital electron density through its HOMO orbital to the metal LUMO to form an adsorption layer, and this has been proved theoretically by the interaction of ligands with Fe30. In addition, we have collected corrosion inhibition data for around 70 organic compounds reported in the literature, and the inhibition data plotted against different inhibitors, showing that amine ligands are good corrosion inhibitors.

  13. CORROSION OF LEAD SHIELDING IN NUCLEAR MATERIALS PACKAGES

    SciTech Connect

    Subramanian, K; Kerry Dunn, K

    2007-11-16

    Inspection of United States-Department of Energy (US-DOE) model 9975 nuclear materials shipping package revealed corrosion of the lead shielding induced by off-gas constituents from organic components in the package. Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of these organic materials. The results showed that the room temperature vulcanizing (RTV) sealant was the most corrosive organic species followed by the polyvinyl acetate (PVAc) glue. The fiberboard material induced corrosion to a much lesser extent than the PVAc glue and RTV, and only in the presence of condensed water. The results indicated faster corrosion at temperatures higher than ambient and with condensed water as expected. A corrosion rate of 0.05 mm/year measured for coupons exposed to the most aggressive conditions was recommended as a conservative estimate for use in package performance calculations.

  14. Duralumin and Its Corrosion

    NASA Technical Reports Server (NTRS)

    Nelson, WM

    1927-01-01

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

  15. Automated Corrosion Detection Program

    DTIC Science & Technology

    2001-10-01

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

  16. Corrosion: ASM metals handbook

    SciTech Connect

    Not Available

    1987-01-01

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

  17. Aggregation of dipolar molecules in SiO2 hybrid organic-inorganic films: use of silver nanoparticles as inhibitors of molecular aggregation

    NASA Astrophysics Data System (ADS)

    Franco, Alfredo; García-Macedo, Jorge; Brusatin, Giovanna; Guglielmi, Massimo

    2013-04-01

    The technological implementation of hybrid organic-inorganic materials in second order nonlinear optical photonic devices depends strongly on the ability of the host matrixes to contain high loads of dipolar molecules without aggregation. Some organic molecules are often used to diminish the attracting interactions between dipolar molecules in such kind of materials, but their efficiency as inhibitors of molecular aggregation is limited by their polarizability. In this work, we report the use of silver nanoparticles as inhibitors of molecular aggregation in hybrid organic-inorganic films doped with dipolar molecules. The large polarizability of the silver nanoparticles makes them ideal moieties for the inhibition of the electrostatic interactions between dipolar nonlinear optical molecules. The average size of the silver nanoparticles in this work was 70.5 nm in diameter, they were synthesized using silver nitrate (AgNO3) as precursor and aminoethylaminopropyltrimethoxysilane as reducing agent. These nanoparticles were immersed in SiO2 hybrid organic-inorganic sol-gel films doped with dipolar chromophores to study their effect as inhibitors of dipolar chromophores aggregation. The presence of the silver nanoparticles in the solid films was confirmed by transmission electronic microscopy and UV-Visible spectroscopy. UV-Visible spectroscopy was also used to monitor the dipolar chromophores aggregation in the SiO2 films. We found that, at room temperature, silver nanoparticles are good inhibiting chromophores aggregation in comparison with the performance of organic inhibitors.

  18. Evaluation of Corrosion Inhibitors as Lubricity Improvers

    DTIC Science & Technology

    1988-07-01

    graduated reticule permits the major and minor azis of the scar to be measured to the nearest 0.01 mm. The average of the two measurements is...dimer acids, 18 percent monomer acids, and 13 percent rosins. It is a by- product of pine tree cellulose processing. The low percentage of trinar acid

  19. Ant nest corrosion -- Exploring the labyrinth

    SciTech Connect

    Elliott, P.; Corbett, R.A.

    1999-07-01

    The phenomenon of ant nest (formicary) corrosion is reviewed. Current theories indicate that attack requires the simultaneous presence of moisture, oxygen and a corrodent, usually an organic acid, such as formic acid. Morphological features are presented using several recent case studies as examples. This paper seeks to create more answers to this less appreciated phenomenon that causes premature corrosion failure in copper tubes used typically for refrigeration or air conditioning applications.

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

    NASA Astrophysics Data System (ADS)

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

    2014-08-01

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

  1. Using Caenorhabditis elegans as a model organism for evaluating extracellular signal-regulated kinase docking domain inhibitors

    PubMed Central

    Chen, Fengming; MacKerell, Alexander D.; Luo, Yuan

    2008-01-01

    We have recently identified several novel ATP-independent inhibitors that target the extracellular signal-regulated kinase-2 (ERK2) protein and inhibit substrate phosphorylation. To further characterize these compounds, we describe the use of C. elegans as a model organism. C. elegans is recognized as a versatile and cost effective model for use in drug development. These studies take advantage of the well characterized process of vulva development and egg laying, which requires MPK-1, the homolog to human ERK2. It is shown that treatment of C. elegans eggs or larvae prior to vulva formation with a previously identified lead compound (76) caused up to 50% reduction in the number of eggs produced from the adult worm. In contrast, compound 76 had no effect on egg laying in young adult or adult worms with fully formed vulva. The reduction in egg laying by the test compound was not due to effects on C. elegans life span, general toxicity, or non-specific stress. However, compound 76 did show selective inhibition of phosphorylation of LIN-1, a MPK-1 substrate essential for vulva precursor cell formation. Moreover, compound 76 inhibited cell fusion necessary for vulva maturation and reduced the multivulva phenotype in LET-60 (Ras) mutant worms that have constitutive activation of MPK-1. These findings support the use of C. elegans as a model organism to evaluate the selectivity and specificity of novel ERK targeted compounds. PMID:19105050

  2. Using Caenorhabditis elegans as a model organism for evaluating extracellular signal-regulated kinase docking domain inhibitors.

    PubMed

    Chen, Fengming; Mackerell, Alexander D; Luo, Yuan; Shapiro, Paul

    2008-12-01

    We have recently identified several novel ATP-independent inhibitors that target the extracellular signal-regulated kinase-2 (ERK2) protein and inhibit substrate phosphorylation. To further characterize these compounds, we describe the use of C. elegans as a model organism. C. elegans is recognized as a versatile and cost effective model for use in drug development. These studies take advantage of the well characterized process of vulva development and egg laying, which requires MPK-1, the homolog to human ERK2. It is shown that treatment of C. elegans eggs or larvae prior to vulva formation with a previously identified lead compound (76) caused up to 50% reduction in the number of eggs produced from the adult worm. In contrast, compound 76 had no effect on egg laying in young adult or adult worms with fully formed vulva. The reduction in egg laying by the test compound was not due to effects on C. elegans life span, general toxicity, or non-specific stress. However, compound 76 did show selective inhibition of phosphorylation of LIN-1, a MPK-1 substrate essential for vulva precursor cell formation. Moreover, compound 76 inhibited cell fusion necessary for vulva maturation and reduced the multivulva phenotype in LET-60 (Ras) mutant worms that have constitutive activation of MPK-1. These findings support the use of C. elegans as a model organism to evaluate the selectivity and specificity of novel ERK targeted compounds.

  3. Role of mTOR inhibitors for the control of viral infection in solid organ transplant recipients.

    PubMed

    Pascual, Julio; Royuela, Ana; Fernández, Ana M; Herrero, Ignacio; Delgado, Juan F; Solé, Amparo; Guirado, Lluis; Serrano, Trinidad; de la Torre-Cisneros, Julián; Moreno, Asunción; Cordero, Elisa; Gallego, Roberto; Lumbreras, Carlos; Aguado, José M

    2016-12-01

    Appropriate post-transplant immunosuppressive regimens that avoid acute rejection, while reducing risk of viral reactivation, have been sought, but remain a chimera. Recent evidence suggesting potential regulatory and antiviral effects of mammalian target of rapamycin inhibitors (mTORi) is of great interest. Although the concept of an immunosuppressive drug with antiviral properties is not new, little effort has been made to put the evidence together to assess the management of immunosuppressive therapy in the presence of a viral infection. This review was developed to gather the evidence on antiviral activity of the mTORi against the viruses that most commonly reactivate in adult solid organ recipients: cytomegalovirus (CMV), polyomavirus, Epstein-Barr virus (EBV), human herpesvirus 8 (HHV8), and hepatitis C virus (HCV). A rapid review methodology and evaluation of quality and consistency of evidence based on the GRADE system was used. The existing literature was variable in nature, although indicating a potential advantage of mTORi in CMV, polyomavirus, and HHV8 infection, and a most doubtful relation with EBV and HCV infection. Several recommendations about the management of these infections are presented that can change certain current patterns of immunosuppression and help to improve the prognosis of the direct and indirect effects of viral infection in solid organ recipients.

  4. Marine and offshore corrosion

    SciTech Connect

    Chandler, K.A.

    1985-01-01

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

  5. Modulation of Donor-Specific Antibody Production After Organ Transplantation by Valproic Acid: A Histone Deacetylase Inhibitor.

    PubMed

    Ye, Junsheng; Li, Juan; Zhou, Minjie; Xia, Renfei; Liu, Rumin; Yu, Lixin

    2016-11-01

    Antibody-mediated rejection, mediated by donor-specific antibodies, is emerging as a leading cause for allograft dysfunction in organ transplantation. Histone deacetylase inhibitors (HDACi) have potential immunosuppressive action, but their effects on antibody-mediated rejection and B cell function in organ transplantation have not been fully explored. The impacts of valproic acid (VPA), an HDACi, on isolated murine B cell proliferation, apoptosis, class switch recombination (CSR), differentiation, and secretion of immunoglobulin were investigated in vitro and in vivo. Molecular mechanisms were also explored by analyzing the expression of the activation-induced cytidinedeaminase, B lymphocyte-induced maturation protein-1 (Blimp-1/Pridm1), X-box-binding protein 1 and interferon-regulatory factor 4. Mouse cardiac transplant model was used to evaluate the regulatory effects of VPA on B cell response in vivo. Valproic acid significantly inhibited B cell CSR, plasma cell differentiation, thereby reduced antibody generation in a dose-dependent manner without altering B cell proliferation and apoptosis in vitro and in vivo. Activation-induced cytidinedeaminase, Blimp-1/Pridm1 and X-box-binding protein 1 expression were repressed by VPA treatment in a dose-dependent manner, whereas no obvious changes were observed on interferon-regulatory factor 4 expression. Although VPA alone did not prolong the graft medium survival time after murine heart transplantation, the low levels of donor-specific antibody, especially IgG in serum and the less numbers of plasma cells in the spleen were observed in VPA-treated mice. Valproic acid inhibited B cell CSR and plasma cell differentiation in vitro and in nitrophenyl-chicken gamma globulin-immunized and heart transplant recipient mice. HDACi might be a therapeutic agent targeting B cell response after organ transplantation.

  6. Hanford double shell waste tank corrosion studies - final report FY2014

    SciTech Connect

    Wiersma, B. J.; Fuentes, R. E.; Hicks, K.

    2014-12-19

    SRNL tasks for FY14 included studies to evaluate the susceptibility of carbon steel to vapor space corrosion (VSC), liquid-air interface (LAI) corrosion, and pitting corrosion. Additionally, SRNL evaluated the susceptibility of carbon steel to pitting corrosion under buffered waste conditions, with the objective of determining the adequate amount of inhibitor (e.g., nitrite) necessary to mitigate pitting corrosion. Other CPP experiments were performed in historical waste simulants and the results were compared to previously gathered results. The results of these activities were utilized to assess the robustness of the standardized CPP protocol

  7. Vanadium corrosion studies. Final report, 1 February 1989-30 June 1993

    SciTech Connect

    Bornstein, N.; Roth, H.; Pike, R.

    1993-06-30

    Vanadium present in certain crude and residual fuel oils, is converted within the burner of the gas turbine engine to the refractory dioxide, which in flight is fully oxidized to the pentoxide. Yttrium oxide, stable in the presence of the oxides of sulfur is identified and verified as a corrosion inhibitor. A chelation process to produce a hydrolytic stable fuel soluble yttrium additive is described.... Vanadium oxide corrosion, Hot corrosion, Sulfidation corrosion, Hot corrosion attenuation, Fuel additives, Water stable fuel soluble yttrium compounds, Chelation.

  8. Prevention of corrosion with polyaniline

    NASA Technical Reports Server (NTRS)

    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.

  9. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1995-01-01

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

  10. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, T.D.

    1996-07-23

    Ceramic materials are disclosed which exhibit stability in severely-corrosive environments having high alkali-metal activity, high sulfur/sulfide activity and/or molten halides at temperatures of 200--550 C or organic salt (including SO{sub 2} and SO{sub 2}Cl{sub 2}) at temperatures of 25--200 C. These sulfide ceramics form stoichiometric (single-phase) compounds with sulfides of Ca, Li, Na, K, Al, Mg, Si, Y, La, Ce, Ga, Ba, Zr and Sr and show melting-points that are sufficiently low and have excellent wettability with many metals (Fe, Ni, Mo) to easily form metal/ceramic seals. Ceramic compositions are also formulated to adequately match thermal expansion coefficient of adjacent metal components. 1 fig.

  11. Corrosion resistant ceramic materials

    DOEpatents

    Kaun, Thomas D.

    1996-01-01

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

  12. Chymotrypsin protease inhibitor gene family in rice: Genomic organization and evidence for the presence of a bidirectional promoter shared between two chymotrypsin protease inhibitor genes.

    PubMed

    Singh, Amanjot; Sahi, Chandan; Grover, Anil

    2009-01-01

    Protease inhibitors play important roles in stress and developmental responses of plants. Rice genome contains 17 putative members in chymotrypsin protease inhibitor (ranging in size from 7.21 to 11.9 kDa) gene family with different predicted localization sites. Full-length cDNA encoding for a putative subtilisin-chymotrypsin protease inhibitor (OCPI2) was obtained from Pusa basmati 1 (indica) rice seedlings. 620 bp-long OCPI2 cDNA contained 219 bp-long ORF, coding for 72 amino acid-long 7.7 kDa subtilisin-chymotrypsin protease inhibitor (CPI) cytoplasmic protein. Expression analysis by semi-quantitative RT-PCR analysis showed that OCPI2 transcript is induced by varied stresses including salt, ABA, low temperature and mechanical injury in both root and shoot tissues of the seedlings. Transgenic rice plants produced with OCPI2 promoter-gus reporter gene showed that this promoter directs high salt- and ABA-regulated expression of the GUS gene. Another CPI gene (OCPI1) upstream to OCPI2 (with 1126 bp distance between the transcription initiation sites of the two genes; transcription in the reverse orientation) was noted in genome sequence of rice genome. A vector that had GFP and GUS reporter genes in opposite orientations driven by 1881 bp intergenic sequence between the OCPI2 and OCPI1 (encompassing the region between the translation initiation sites of the two genes) was constructed and shot in onion epidermal cells by particle bombardment. Expression of both GFP and GUS from the same epidermal cell showed that this sequence represents a bidirectional promoter. Examples illustrating gene pairs showing co-expression of two divergent neighboring genes sharing a bidirectional promoter have recently been extensively worked out in yeast and human systems. We provide an example of a gene pair constituted of two homologous genes showing co-expression governed by a bidirectional promoter in rice.

  13. Progress in combating microbiologically induced corrosion in oil production

    SciTech Connect

    Ciaraldi, S.W.; Ghazal, H.H.; Abou Shadey, T.H.; El-Leil, H.A.; El-Raghy, S.M.

    1999-11-01

    Widespread microbial activity has caused substantial recent corrosion problems throughout a major mature oil production operation. Control over this situation is gradually being gained through advances in several areas, These include improved understanding of the reservoir souring process, operational factors contributing to biocell formation/propagation, the role of bio-breeders in promoting corrosion and the kinetics of attack. Synergistic beneficial effects of cleaning programs (pigging, chemical treatments, etc.) and biocide/corrosion inhibitor injections have now been well demonstrated, with corrosion rates reduced to nil in many places, even in significantly damaged systems. Feasibility studies of new de-souring technologies have been performed with encouraging results and these offer the potential for successful and cost-effective long-term control of microbiologically induced corrosion (MIC) in several possible operational areas.

  14. Non-corrosive creosote and soot removing composition

    SciTech Connect

    Mackowiak, L.S.; Ellison, F.E.; Fidler, J.W.; Tucker, N.G.; Varma, G.M.N.

    1984-11-06

    A metallic chloride based creosote and soot removing composition including a phosphate corrosion inhibitor to reduce the corrosive attack on metal flue pipes is provided. The composition includes between about 15-60% metallic chloride, 20-60% trisodium phosphate dodecylhydrate, 15-60% anti-cake agents, such as non-swelling clay, sodium sulfate and tricalcium phosphate and 2-10% combustion initiator, such as wood flour.

  15. Retention behavior of proton pump inhibitors using immobilized polysaccharide-derived chiral stationary phases with organic-aqueous mobile phases.

    PubMed

    Cirilli, Roberto; Ferretti, Rosella; Gallinella, Bruno; Zanitti, Leo

    2013-08-23

    In the present study, the chromatographic behavior of two immobilized polysaccharide-derived chiral stationary phases (CSPs), the Chiralpak ID-3 and Chiralpak IE-3, under aqueous mobile phases conditions is presented. Four proton pump inhibitors (PPIs) (omeprazole, lansoprazole, pentaprazole and rabeprazole) were selected as test compounds. The effect of the concentration of water in the mobile phase was investigated with respect to its contribution to enantioselectivity and retention. Under acetonitrile-water mobile phase conditions, retention behavior evidenced an interesting pattern. At lower water content, the retention factors decreased with increasing water and at higher water content a reversed trend was observed. These findings support the hypothesis that two retention mechanisms operated successively on the same CSP: the HILIC (with water-poor eluents) and RPLC (with water-rich eluents) modes. The retention factors were minimum in the intermediate region, corresponding to a water concentration of about 20%. Interestingly, the baseline separation of all PPIs investigated was optimized under organic-aqueous mobile phases containing a high water content (from about 50 to 65%). Thus, the dual retention behavior of the PPIs on the Chiralpak ID-3 and Chiralpak IE-3 made it possible to reach greener and harmless enantioselective conditions in a short analysis time.

  16. SRB seawater corrosion project

    NASA Technical Reports Server (NTRS)

    Bozack, M. J.

    1991-01-01

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

  17. Corrosion, microstructure, and metallography

    SciTech Connect

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

    1985-01-01

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

  18. Stress corrosion resistant fasteners

    NASA Technical Reports Server (NTRS)

    Roach, T. A.

    1985-01-01

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

  19. PD98059, a specific MAP kinase inhibitor, attenuates multiple organ dysfunction syndrome/failure (MODS) induced by zymosan in mice.

    PubMed

    Di Paola, Rosanna; Galuppo, Maria; Mazzon, Emanuela; Paterniti, Irene; Bramanti, Placido; Cuzzocrea, Salvatore

    2010-02-01

    PD98059 (MEK1 Inhibitor) has been shown to act in vivo as a highly selective inhibitor of MEK1 activation and the MAP kinase cascade. In the present study, we have investigated the effects of PD98059, on the development of non-septic shock caused by zymosan in mice. Mice received either intraperitoneally zymosan (500mg/kg, administered i.p. as a suspension in saline) or vehicle (0.25ml/mouse saline). PD98059 (10mg/kg) was administered 1 and 6h after zymosan administration i.p. Organ failure and systemic inflammation in mice was assessed 18h after administration of zymosan and/or PD98059. Treatment of mice with PD98059 attenuated the peritoneal exudation and the migration of polymorphonuclear cells caused by zymosan. PD98059 also attenuated the lung, liver and pancreatic injury and renal dysfunction caused by zymosan as well as the increase of TNF-alpha and IL-1beta plasma levels caused by zymosan. Immunohistochemical analysis for inducible nitric oxide synthase (iNOS), nitrotyrosine, poly(ADP-ribose) (PAR), ICAM-1, P-selectin, Bax, Bcl-2 and FAS-ligand revealed positive staining in pancreatic and intestinal tissue obtained from zymosan-injected mice. The degree of staining for nitrotyrosine, iNOS, PAR, ICAM-1, P-selectin, Bax, Bcl-2 and FAS-ligand were markedly reduced in tissue sections obtained from zymosan-injected mice, which had received PD98059. Moreover treatment of mice with PD98059 (10mg/kg) attenuated the NF-kappaB activation and mitogen-activated protein kinases (MAPK) expression induced by zymosan injection. In addition, administration of zymosan caused a severe illness in the mice characterized by a systemic toxicity, significant loss of body weight and a 60% of mortality at the end of observation period. Treatment with PD98059 significantly reduced the development of systemic toxicity, the loss in body weight and the mortality (20%) caused by zymosan. This study provides evidence that PD98059 attenuates the degree of zymosan-induced non-septic shock

  20. Influence of biofilm formation on corrosion and scaling in geothermal plants

    NASA Astrophysics Data System (ADS)

    Kleyböcker, Anne; Lerm, Stephanie; Monika, Kasina; Tobias, Lienen; Florian, Eichinger; Andrea, Seibt; Markus, Wolfgramm; Hilke, Würdemann

    2017-04-01

    Process failures may occur due to corrosion and scaling processes in open loop geothermal systems. Especially after heat extraction, sulfate reducing bacteria (SRB) contribute to corrosion processes due to a more favorable temperature for their growth. In biofilms containing FeS scales, corrosion processes are enhanced. Furthermore, scales can lead to reduced pipe profiles, to a diminished heat transfer and a decrease in the wellbore injectivity. Inhibitors are frequently applied to minimize scaling in technical systems. A prerequisite for the application of inhibitors in geothermal plants located in the Molasse basin is their degradability under reservoir conditions, e. g. in a reduced environment. In order to determine the effects of scale-inhibitors on the subsurface and microbial processes, laboratory experiments were performed focusing on the microbial inhibitor degradation. First results indicate that the inhibitor degradation under anaerobic conditions is possible. Besides the inhibitor application also other techniques are investigated to economically reduce corrosion and scaling in geothermal plants. In a mobile bypass system, the influence of biofilm formation on corrosion and scaling was investigated. The bypass system was tested at a geothermal heat store in the North German Basin. The plant is operated with highly saline fluid (salinity 130 g/L) and known to be affected by SRB. The SRB contributed to corrosion damages especially at the pump in the well on the cold side. Heat shocks were successfully used in the bypass system to reduce biofilm formation as well as corrosion and scaling processes.

  1. Galvanic Corrosion Initiatives

    DTIC Science & Technology

    1987-12-01

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

  2. Genetic Algorithm and Self-Organizing Maps for QSPR Study of Some N-aryl Derivatives as Butyrylcholinesterase Inhibitors.

    PubMed

    Ahmadi, Shahin; Ganji, Soroush

    2016-01-01

    Alzheimer's disease is the most common form of dementia, characterized by loss of neurons and synapses in the cerebral cortex and certain subcortical regions, leading to altered and unsuitable activities. In this study, we focused on the influence of rndom selection (RS) and SOMs (self-organizing maps) data splitting on the external predictivity of quantitative structure-property relationship (QSPR) models of some N-ary derivatives as butyrylcholinesterase (BChE) inhibitors. A QSPR model relates molecular descriptors to a chemical property can save time and money in drug discovery and development. Model validation is a critical step in QSPR model generation; for this purpose, it is necessary to carry out the data splitting on original data set. The GA is very useful for finding global minima for high dimensionality of the problem (e.g. variable selection in QSPR) when response surface has many local optima. The molecular structures and experimental values for inhibition constants of BChE catalytic activities obtained from the literature. In this study, total number of 88 compounds was divided into training and test set by means of RS and SOM methods. The Chem3D module was used in order to create the 3D structures of compounds; geometry optimization, using the Polak-Ribiere algorithm. Using Dragon package over 1145 molecular descriptors such as 3D-MoRSE, GETAWAY and WHIM descriptors were derived to characterize the structures of ChEs inhibitors derivatives, properly. The constant variables, variables which have low correlation with response and collinear descriptors were omitted, and the number of descriptors was reduced to 422 in the data set. The QSAR models were constructed using stepwise-MLR and GA-MLR. The best MLR models with four, five and six variables were built to obtain the best QSAR model. The best multivariate linear models in both stepwise-MLR and GA-MLR methods had five variables. The best significant relationships, using comparison of Q2 of models

  3. Evaluating the corrosion resistance of multi-element metal coatings

    NASA Astrophysics Data System (ADS)

    Eremin, E. N.; Yurov, V. M.; Platonova, Ye. S.; Syzdykova, A. Sh.; Guchenko, S. A.

    2017-08-01

    The paper presents evaluating the corrosion resistance of ion-plasma coatings obtained using the cathodes: Zr, Al, Cu, Al-Fe, Zn-Al, Zn-Cu-Al and the stainless steel cathode 12X18H10T. The ordered columnar structure arising from the self-organization of plasma coatings is discovered. It is stated that the corrosion resistance of the greater part of the investigated coatings is similar to the most corrosion-resistant steels. To improve the corrosion resistance of metallic coatings it is recommended to increase its surface tension. This requires using the most refractory metals as alloying additives.

  4. Handbook of corrosion data

    SciTech Connect

    Craig, D.

    1989-01-01

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

  5. Using Corrosion Design Models to Accelerate the Transition of Alternatives

    DTIC Science & Technology

    2012-08-01

    Corrosion Design Models • All moving to incorporate light metals, composites and other aviation materials • Maturation includes effect of...Using Corrosion Design Models to Accelerate the Transition of Alternatives Craig Matzdorf Materials Engineering Division Naval Air...TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Naval Air Warfare Center, Materials Engineering Division,22347

  6. Microbial Iron Respiration Can Protect Steel from Corrosion

    PubMed Central

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

    2002-01-01

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

  7. Prediction of Corrosion of Advanced Materials and Fabricated Components

    SciTech Connect

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

    2007-09-29

    -base alloys, stainless steels and copper-nickel alloys and (2) the effects of heat treatment on localized corrosion. Excellent agreement with experimental data has been obtained for alloys in various environments, including acids, bases, oxidizing species, inorganic inhibitors, etc. Further, a probabilistic model has been established for predicting the long-term damage due to localized corrosion on the basis of short-term inspection results. This methodology is applicable to pitting, crevice corrosion, stress corrosion cracking and corrosion fatigue. Finally, a comprehensive model has been developed for predicting sensitization of Fe-Ni-Cr-Mo-W-N alloys and its effect on localized corrosion. As a vehicle for the commercialization of this technology, OLI Systems has developed the Corrosion Analyzer, a software tool that is already used by many companies in the chemical process industry. In process design, the Corrosion Analyzer provides the industry with (1) reliable prediction of the tendency of base alloys for localized corrosion as a function of environmental conditions and (2) understanding of how to select alloys for corrosive environments. In process operations, the software will help to predict the remaining useful life of equipment based on limited input data. Thus, users will also be able to identify process changes, corrosion inhibition strategies, and other control options before costly shutdowns, energy waste, and environmental releases occur. With the Corrosion Analyzer, various corrosion mitigation measures can be realistically tested in a virtual laboratory.

  8. Potential for erosion corrosion of SRS high level waste tanks

    SciTech Connect

    Zapp, P.E.

    1994-01-01

    SRS high-level radioactive waste tanks will not experience erosion corrosion to any significant degree during slurry pump operations. Erosion corrosion in carbon steel structures at reported pump discharge velocities is dominated by electrochemical (corrosion) processes. Interruption of those processes, as by the addition of corrosion inhibitors, sharply reduces the rate of metal loss from erosion corrosion. The well-inhibited SRS waste tanks have a near-zero general corrosion rate, and therefore will be essentially immune to erosion corrosion. The experimental data on carbon steel erosion corrosion most relevant to SRS operations was obtained at the Hanford Site on simulated Purex waste. A metal loss rate of 2.4 mils per year was measured at a temperature of 102 C and a slurry velocity comparable to calculated SRS slurry velocities on ground specimens of the same carbon steel used in SRS waste tanks. Based on these data and the much lower expected temperatures, the metal loss rate of SRS tanks under waste removal and processing conditions should be insignificant, i.e. less than 1 mil per year.

  9. Application of simulation techniques for internal corrosion prediction

    SciTech Connect

    Palacios T, C.A.; Hernandez, Y.

    1997-08-01

    Characterization of corrosion in the oil and gas industry is becoming of increasing importance for safety reasons as well as for the preservation of production facilities; to prevent down time and damage to the environment. This article presents the methodology used by this company to characterize the corrosion behavior of the whole production facility, taking into consideration the hydrodynamic and thermodynamic conditions of the produced fluids (flow velocities, flow pattern, liquid holdup, pressure, temperature, etc.) as they flow from the reservoir through the surface installations (flowlines, gas/oil gathering and transmission lines, gas processing plants, artificial lift systems, etc.). The methodology uses Petroleum Engineering and Two-Phase modeling techniques to: (1) optimize the entire production system to obtain the most efficient objective flow rate taking into consideration the corrosive/erosive nature of the produced fluid and (2) characterize the corrosive nature of the produced fluid as it flows through the above mentioned installations. The modeling techniques were performed using commercially available simulators and CO{sub 2} corrosion rates were determined using well known published correlations. For H{sub 2}S corrosion, NACE MR0175 criteria is applied. The application of this methodology has allowed corrosion control strategies, protection and monitoring criteria, inhibitor optimization and increased the effectiveness of already existing corrosion control systems.

  10. Smart Multifunctional Coatings for Corrosion Detection and Control in the Aerospace Industry

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina

    2015-01-01

    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.

  11. Anti-Corrosion Performance of 1,3-BENZOTHIAZOLE on 410 Martensitic Stainless Steel in H2SO4

    NASA Astrophysics Data System (ADS)

    Loto, Roland Tolulope

    The corrosion inhibition effect of synthesized 1,3-benzothiazole at very low concentrations on 410 martensitic stainless steel in 3MH2SO4 solution was studied through potentiodynamic polarization and weight loss measurements. The observation showed that the organic compound performed effectively with average inhibition efficiencies of 94% and 98% at the concentrations studied from both electrochemical methods due to the inhibition action of protonated inhibitor molecules in the acid solution. The amine and aromatics functional groups of the molecules active in the corrosion inhibition reaction were exposed from Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopic analysis. Thermodynamic calculations showed cationic adsorption to be chemisorption adsorption, obeying the Langmuir adsorption isotherm. Images from optical microscopy showed an improved morphology in comparison to images from corroded stainless steel. Severe surface deterioration and macro-pits were observed in the uninhibited samples.

  12. Sea water corrosion. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-12-01

    The bibliography contains citations concerning the corrosion of ships, offshore platforms, steel pilings, cables, and marine equipment. The materials studied include ferrous and nonferrous metals, concrete, and composites. Considerable attention is given to materials selection and testing for the Ocean Thermal Energy Conversion (OTEC) projects. References to corrosion inhibitors are included. (Contains 250 citations and includes a subject term index and title list.)

  13. Sea water corrosion. (Latest citations from the NTIS data base). Published Search

    SciTech Connect

    Not Available

    1992-04-01

    The bibliography contains citations concerning the corrosion of ships, offshore platforms, steel pilings, cables, and marine equipment. The materials studied include ferrous and nonferrous metals, concrete, and composites. Considerable attention is given to materials selection and testing for the Ocean Thermal Energy Conversion (OTEC) projects. References to corrosion inhibitors are included. (Contains 250 citations and includes a subject term index and title list.)

  14. Sea water corrosion. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-01-01

    The bibliography contains citations concerning the corrosion of ships, offshore platforms, steel pilings, cables, and marine equipment. The materials studied include ferrous and nonferrous metals, concrete, and composites. Considerable attention is given to materials selection and testing for the Ocean Thermal Energy Conversion (OTEC) projects. References to corrosion inhibitors are included. (Contains 250 citations and includes a subject term index and title list.)

  15. Fireside Corrosion USC Steering

    SciTech Connect

    G. R. Holcomb; J. Tylczak

    2011-09-07

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

  16. Demystifying Controlling Copper Corrosion

    EPA Science Inventory

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

  17. Potentiodynamic Corrosion Testing.

    PubMed

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

    2016-09-04

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

  18. Demystifying Controlling Copper Corrosion

    EPA Science Inventory

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

  19. Reduce FCC corrosion

    SciTech Connect

    Walker, H.B.

    1984-01-01

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

  20. Crude unit corrosion and corrosion control

    SciTech Connect

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

    1996-08-01

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

  1. DEVELOPMENT OF A REPRODUCIBLE SCREENING METHOD TO DETERMINE THE MECHANISM AND EFFECT OF ORGANIC ACIDS AND OTHER CONTAMINANTS ON THE CORROSION OF ALUMINUM-FINNED COPPER-TUBE HEAT EXCHANGE COILS

    SciTech Connect

    Richard A. Corbett; Dave Severance

    2005-02-01

    Formicary corrosion is an insidious form of localized pitting corrosion. Notoya (1997b) wrote, ?In Japan, this type of corrosion is found in approximately 10% of cases of premature failure of copper tubes.? Attack characteristically features very small surface pits which are not visible to the un-aided eye, and random directional changes in the underlying copper metal. Attack is rapid. Failures have occurred before installation, shortly thereafter, or within several years later. Objectives of this Research Project Conduct an in depth literature search on the subject of formicary corrosion. Define the corrosion mechanism. Develop a test method that will reproduce formicary corrosion. Develop a test method for screening candidate materials that could cause formicary corrosion.

  2. Evidence for a role of human organic anion transporters in the muscular side effects of HMG-CoA reductase inhibitors.

    PubMed

    Takeda, Michio; Noshiro, Rie; Onozato, Maristela Lika; Tojo, Akihiro; Hasannejad, Habib; Huang, Xiu-Lin; Narikawa, Shinichi; Endou, Hitoshi

    2004-01-12

    The purpose of this study was to elucidate the role of human organic anion transporters (human OATs) in the induction of drug-induced skeletal muscle abnormalities. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors have been clinically used for lowering plasma cholesterol levels, and are known to induce various forms of skeletal muscle abnormalities including myopathy and rhabdomyolysis. Immunohistochemical analysis revealed that human OAT1 and human OAT3 are localized in the cytoplasmic membrane of the human skeletal muscles. The activities of human OATs were measured using mouse cell lines from renal proximal tubules stably expressing human OATs. Human OAT3, but not human OAT1, mediates the transport of pravastatin. Fluvastatin inhibited organic anion uptake mediated by human OAT1 in a mixture of competitive and noncompetitive manner, whereas simvastatin and fluvastatin noncompetitively inhibited the organic anion uptake mediated by human OAT3. In conclusion, the organic anion transporters OAT1 and OAT3 are localized in the cytoplasmic membrane of human skeletal muscles. Pravastatin, simvasatin, and fluvasatin inhibit human OATs activity. These results suggest that muscle organic anion transporters play a role in the muscular side effects of HMG-CoA reductase inhibitors.

  3. Monofluorophosphate is a selective inhibitor of respiratory sulfate-reducing microorganisms.

    PubMed

    Carlson, Hans K; Stoeva, Magdalena K; Justice, Nicholas B; Sczesnak, Andrew; Mullan, Mark R; Mosqueda, Lorraine A; Kuehl, Jennifer V; Deutschbauer, Adam M; Arkin, Adam P; Coates, John D

    2015-03-17

    Despite the environmental and economic cost of microbial sulfidogenesis in industrial operations, few compounds are known as selective inhibitors of respiratory sulfate reducing microorganisms (SRM), and no study has systematically and quantitatively evaluated the selectivity and potency of SRM inhibitors. Using general, high-throughput assays to quantitatively evaluate inhibitor potency and selectivity in a model sulfate-reducing microbial ecosystem as well as inhibitor specificity for the sulfate reduction pathway in a model SRM, we screened a panel of inorganic oxyanions. We identified several SRM selective inhibitors including selenate, selenite, tellurate, tellurite, nitrate, nitrite, perchlorate, chlorate, monofluorophosphate, vanadate, molydate, and tungstate. Monofluorophosphate (MFP) was not known previously as a selective SRM inhibitor, but has promising characteristics including low toxicity to eukaryotic organisms, high stability at circumneutral pH, utility as an abiotic corrosion inhibitor, and low cost. MFP remains a potent inhibitor of SRM growing by fermentation, and MFP is tolerated by nitrate and perchlorate reducing microorganisms. For SRM inhibition, MFP is synergistic with nitrite and chlorite, and could enhance the efficacy of nitrate or perchlorate treatments. Finally, MFP inhibition is multifaceted. Both inhibition of the central sulfate reduction pathway and release of cytoplasmic fluoride ion are implicated in the mechanism of MFP toxicity.

  4. Corrosion and corrosion inhibition of Al and some alloys in sulphate solutions containing halide ions investigated by an impedance technique

    NASA Astrophysics Data System (ADS)

    Rehim, Sayed S. Abdel; Hassan, Hamdi H.; Amin, Mohammed A.

    2002-02-01

    This paper reports the results of impedance measurements on the corrosion behaviour of pure Al, (Al+6%Cu) and (Al+6%Si) alloys in Na 2SO 4 solutions in the absence and presence of NaCl, NaBr and NaI under the influence of various experimental variables at the open circuit potential (OCP). We find that in the absence of halide ions the rates of corrosion of the three Al samples are enhanced with increasing concentration, acidity, and alkalinity of the Na 2SO 4 solution and in the presence of halide ions. The corrosion resistance increases in the order Al<(Al+6%Cu)<(Al+6%Si). The aggressiveness of the halide ions towards the corrosion of Al and its two alloys increases in the order: I -
    inhibitors on the corrosion inhibition of pure Al and its alloys in (0.5 M Na 2SO 4+0.2 M NaCl) solution (except NO 3-) are to inhibit the corrosion of the three samples to an extent depending on the nature of the inhibitor.

  5. Anti-Corrosion Nanotechnology Solutions for DoD Applications

    DTIC Science & Technology

    2010-02-11

    Materials) – Hybrid inorganic- organic elastomeric nanocoating system (primer + topcoat) designed for erosion, corrosion, and cavitation protection. 7...Surface Technologies) – Superhydrophobic aerogel coating for protecting printed electronic circuit boards. 11 • Teslan (Tesla Nanocoatings ) – Carbon

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

    SciTech Connect

    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.

  7. CORROSION OF LEAD SHIELDING IN MODEL 9975 PACKAGE

    SciTech Connect

    Subramanian, K

    2006-03-15

    Experiments were performed to determine the corrosion rate of lead when exposed to off-gas or degradation products of organic materials used in the model 9975 package.[1] The experiments were completed within the framework of a parametric test matrix with variables of organic configuration, temperature, humidity and the effect of durations of exposure on the corrosion of lead in the 9975 package. The room temperature vulcanizing (RTV) sealant was the most corrosive organic species in the testing, followed by the polyvinyl acetate (PVAc) glue. The Celotex{copyright} material uniquely induced measurable corrosion only in situations with condensed water, and to a much lesser extent than the PVAc glue and RTV. The coupons exhibited faster corrosion at higher temperatures than at room temperatures. There was a particularly pronounced effect of condensed water as the coupons exposed in the cells with condensed water exhibited much higher corrosion rates. In the 9975 package, the PVAc glue was determined to be the most aggressive due to it's proximity in the design. The condition considered most representative of the package conditions is that of the coupon exposed to the Celotex{copyright}/glue organic exposed in the ambient humidity conditions. The corrosion rate of 2 mpy measured in the laboratory experiments for this condition is considered to be a bounding condition to the 9975 package conditions when the laboratory results are extrapolated to actual package conditions, and is recommended as a conservative estimate for package performance calculations.

  8. Corrosion-resistant uranium

    DOEpatents

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

    1983-01-01

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

  9. Corrosion-resistant uranium

    DOEpatents

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

    1981-10-21

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

  10. On-line corrosion control in refinery overhead systems

    SciTech Connect

    Correa, L.A.

    1995-11-01

    Corrosion is one of the great causes of accidents and economic losses in petroleum and petrochemical industries. Crude unit overheads are one of the most corrosion affected parts and large amounts of work and money has been spent on its control and prevention. Thus, new materials, inhibitors and monitoring techniques are constantly under testing in order to improve corrosion prevention and plant reliability. Expert Systems are a rising technology in industrial process monitoring and problem diagnosing. This sort of computer program is developed trying to simulate the human expert intelligent behavior in the task of solving a specific problem. The crude units overhead corrosion control is a hard and time consuming task that seems to be a fruitful field to expert systems application.

  11. More experiences with corrosion and fouling in a refinery amine system

    SciTech Connect

    Litschewski, M.J.

    1996-08-01

    This paper describes a roller coaster ride of corrosion and subsequent fouling in a Refinery MDEA system. The accelerated corrosion was first initiated by addition of caustic and the following up and down corrosion rate was a result of operating conditions imposed by increased sour crude charge, fouling and misapplication of MDEA. System variables that were controlled during this period included equipment metallurgy, the addition of caustic to neutralize heat stable salts (HSS), ion exchange to remove HSS and sodium, amine circulation rate, reboiler steam rate and the injection of a corrosion inhibitor.

  12. Current and potential distributions in corrosion systems

    SciTech Connect

    Smyrl, W.H.

    1980-01-01

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

  13. Synthesis, characterization, and applications of electroactive polymeric nanostructures for organic coatings

    NASA Astrophysics Data System (ADS)

    Suryawanshi, Abhijit Jagnnath

    Electroactive polymers (EAP) such as polypyrrole (PPy) and polyaniline (PANI) are being explored intensively in the scientific community. Nanostructures of EAPs have low dimensions and high surface area enabling them to be considered for various useful applications. These applications are in several fields including corrosion inhibition, capacitors, artificial muscles, solar cells, polymer light emitting diodes, and energy storage devices. Nanostructures of EAPs have been synthesized in different morphologies such as nanowires, nanorods, nanotubes, nanospheres, and nanocapsules. This variety in morphology is traditionally achieved using soft templates, such as surfactant micelles, or hard templates, such as anodized aluminum oxide (AAO). Templates provide stability and groundwork from which the polymer can grow, but the templates add undesirable expense to the process and can change the properties of the nanoparticles by integrating its own properties. In this study a template free method is introduced to synthesize EAP nanostructures of PPy and PANI utilizing ozone oxidation. The simple techniques involve ozone exposure to the monomer solution to produce aqueous dispersions of EAP nanostructures. The synthesized nanostructures exhibit uniform morphology, low particle size distribution, and stability against agglomeration. Ozone oxidation is further explored for the synthesis of silver-PPy (Ag-PPy) core-shell nanospheres (CSNs). Coatings containing PPy nanospheres were formulated to study the corrosion inhibition efficiency of PPy nanospheres. Investigation of the coatings using electrochemical techniques revealed that the PPy nanospheres may provide corrosion inhibition against filiform corrosion by oxygen scavenging mechanism. Finally, organic corrosion inhibitors were incorporated in PPy to develop efficient corrosion inhibiting systems, by using the synergistic effects from PPy and organic corrosion inhibitors.

  14. 3D-QSAR studies on unsaturated 4-azasteroids as human 5alpha-reductase inhibitors: a self organizing molecular field analysis approach.

    PubMed

    Aggarwal, Saurabh; Thareja, Suresh; Bhardwaj, T R; Kumar, Manoj

    2010-02-01

    Azasteroids have been reported as inhibitors of human 5alpha-reductase enzyme. These were designed by substitution of one carbon atom of steroidal A ring by heteroatom nitrogen. Due to lack of information on the crystal structure of human 5alpha-reductase, 3D-QSAR study has been performed on a series of unsaturated 4-azasteroids using Self Organizing Molecular Field Analysis (SOMFA) for rationalizing the molecular properties and human 5alpha-reductase inhibitory activities. The statistical results having good cross-validated r(2)(cv) (0.783), non cross-validated r(2) (0.806) and F-test value (87.282), showed satisfied predictive ability. Analysis of SOMFA models through electrostatic and shape grids provide useful information for the design and optimization of new steroidal human 5alpha-reductase inhibitors.

  15. The corrosion of titanium in alkaline peroxide bleach liquors

    SciTech Connect

    Wyllie, W.E. II; Brown, B.E.; Duquette, D.J.

    1994-12-31

    An experimental program to determine the effects of hydrogen peroxide (H{sub 2}O{sub 2}) and of potential corrosion inhibitors on the corrosion behavior of titanium has been developed. Corrosion rates less than 0.25 mm/y were observed in laboratory bleach liquor at pH 12 to which 5 g/l of H{sub 2}O{sub 2} were added. At pH 13, with 10 g/l H{sub 2}O{sub 2}, the corrosion rates were unacceptably high in both sodium hydroxide (NaOH) and laboratory bleach liquor solutions (>8.38 mm/y). The preliminary results of inhibitor studies indicated that the addition of 3.7 g/l sodium silicate or 0.01 g/l calcium nitrate (Ca(NO{sub 3}){sub 2}) effectively inhibited the corrosion of titanium exposed to 5 g/l of H{sub 2}O{sub 2} in NaOH solutions of pH 12. It was also found that in simulated paper mill chemistries, i.e., basic solutions containing 3.7 g/l sodium silicate and 0.6 g/l EDTA (ethylenediaminetetraacetic acid), corrosion rates increased markedly with the addition of 5 g/l H{sub 2}O{sub 2}. However, subsequent additions of peroxide resulted in corrosion rates which were even lower than those found in NaOH. This is believed to be due to the formation of a black scale on the surface of the sample. The addition of magnesium sulfate (MgSO{sub 4}) in the 0.1--0.5 g/l range also was shown to inhibit corrosion in the NaOH solution, but only after prior exposure to H{sub 2}O{sub 2}.

  16. Effect of pH on corrosion inhibition of steel by polyaspartic acid

    SciTech Connect

    Silverman, D.C.; Kalota, D.J.; Stover, F.S.

    1995-10-01

    Polyaspartic acid, a polymeric form of aspartic acid has been examined as a corrosion inhibitor for steel as a function of pH, temperature, and hydrodynamic conditions. The temperature ranged from 25 C to 95 C and the concentration ranged from less than 1% to about 10% by weight. Experimental procedures included electrochemical impedance spectroscopy, the rotating cylinder electrode, and coupon immersion. At low to neutral pH values, polyaspartic acid increases the corrosion rate of steel. At high pH above about 10, polyaspartic acid is a reasonably robust corrosion inhibitor. Between a pH of 7 and 10, corrosion in the presence of polyaspartic acid is a complex function of temperature, concentration, water quality, and hydrodynamic conditions. By combining corrosion potential measurements with speciation diagrams as obtained by titration, a reasonably cohesive explanation of the behavior has been developed.

  17. Effect of pH on corrosion inhibition of steel by polyaspartic acid

    SciTech Connect

    Silverman, D.C.; Kalota, D.J.; Stover, F.S.

    1995-11-01

    Polyaspartic acid, a polymeric form of aspartic acid (C{sub 4}H{sub 7}NO{sub 4}), was examined as a corrosion inhibitor for steel as a function of pH, temperature, and hydrodynamic conditions. The temperature ranged from 25 C to 95 C, and the concentration ranged from < 1 wt% to {approximately} 10 wt%. Experimental procedures included electrochemical impedance spectroscopy (EIS), the rotating cylinder electrode (RCE), and coupon immersion. At low to neutral pH values, polyaspartic acid increased the corrosion rate of steel. At high pH (< {approximately} 10), polyaspartic acid was a reasonably robust corrosion inhibitor. Between pH 7 and 10, corrosion in the presence of polyaspartic acid was a complex function of temperature concentration, water quality, and hydrodynamic conditions. By combining corrosion potential measurements with speciation diagrams obtained by titration, a reasonably cohesive explanation of the behavior was developed.

  18. BWR steel containment corrosion

    SciTech Connect

    Tan, C.P.; Bagchi, G.

    1996-04-01

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

  19. Microbiologically influenced corrosion of orthodontic metallic appliances.

    PubMed

    Kameda, Takashi; Oda, Hirotake; Ohkuma, Kazuo; Sano, Natsuki; Batbayar, Nomintsetseg; Terashima, Yukari; Sato, Soh; Terada, Kazuto

    2014-01-01

    Biocorrosion (microbiologically influenced corrosion; MIC) occur in aquatic habitats varying in nutrient content, temperature, stress and pH. The oral environment of organisms, including humans, should be one of the most hospitable for MIC. Corrosion of metallic appliances in the oral region is one cause of metal allergy in patients. In this study, an inductively coupled plasma-optical emission spectrometer revealed elution of Fe, Cr and Ni from stainless steel (SUS) appliances incubated with oral bacteria. Three-dimensional laser confocal microscopy also revealed that oral bacterial culture promoted increased surface roughness and corrosion pits in SUS appliances. The pH of the supernatant was lowered after co-culture of appliances and oral bacteria in any combinations, but not reached at the level of depassivation pH of their metallic materials. This study showed that Streptococcus mutans and Streptococcus sanguinis which easily created biofilm on the surfaces of teeth and appliances, did corrode orthodontic SUS appliances.

  20. Functional Phylogeny: the Use of the Sensitivity of Ribosomes to Protein Synthesis Inhibitors as a Tool to Study the Evolution of Organisms

    NASA Astrophysics Data System (ADS)

    Briones, Carlos; Koroutchev, Kostadin; Amils, Ricardo

    1998-10-01

    In order to study the functional phylogeny of organisms, forty different protein synthesis inhibitors with diverse domain and funcional specificities have been used to analyze forty archaeal, bacterial and eukaryotic translational systems. The inhibition curves generated with the different ribosome-antibiotic pairs have shown very interesting similarities among organisms belonging to the same phylogenetic group, confirming the feasibility of using such information in the development of evolutionary studies. A new method to extract most of the information contained in the inhibition curves is presented. Using a statistical treatment based on the principal components analysis of the data, we have defined coordinates for the organisms which have allowed us to perform a functional clustering of them. The phenograms obtained are very similar to those generated by 16/18S rRNA sequence comparison. These results prove the phylogenetic value of our functional analysis and suggest an interesting intersection between genotypic and phenotypic (functional) information.