bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial Pattern Analysis of Heavy Metals in Beijing Agricultural Soils Based on Spatial Autocorrelation Statistics
Authors: Huo Xiao-Ni , Zhang Wei-Wei , Sun Dan-Feng , Li Hong , Zhou Lian-Di , Li Bao-Guo
Published: June 2011

This study explored the spatial pattern of heavy metals in Beijing agricultural soils using Moran’s I statistic of spatial autocorrelation. The global Moran’s I result showed that the spatial dependence of Cr, Ni, Zn, and Hg changed with different spatial weight matrixes, and they had significant and positive global spatial correlations based on distance weight. The spatial dependence of the four metals was scale-dependent on distance, but these scale effects existed within a threshold distance of 13 km, 32 km, 50 km, and 29 km, respectively for Cr, Ni, Zn, and Hg. The maximal spatial positive correlation range was 57 km, 70 km, 57 km, and 55 km for Cr, Ni, Zn, and Hg, respectively and these were not affected by sampling density. Local spatial autocorrelation analysis detected the locations of spatial clusters and spatial outliers and revealed that the pollution of these four metals occurred in significant High-high spatial clusters, Low-high, or even High-low spatial outliers. Thus, three major areas were identified and should be receiving more attention: the first was the northeast region of Beijing, where Cr, Zn, Ni, and Hg had significant increases. The second was the southeast region of Beijing where wastewater irrigation had strongly changed the content of metals, particularly of Cr and Zn, in soils. The third area was the urban fringe around city, where Hg showed a significant increase.
Altered Gene Expression by Low-Dose Arsenic Exposure in Humans and Cultured Cardiomyocytes: Assessment by Real-Time PCR Arrays
Authors: Mo Jinyao , Xia Yajuan , Wade Timothy J. , DeMarini David M. , Davidson Mercy , Mumford Judy
Published: June 2011

Chronic arsenic exposure results in higher risk of skin, lung, and bladder cancer, as well as cardiovascular disease and diabetes. The purpose of this study was to investigate the effects on expression of selected genes in the blood lymphocytes from 159 people exposed chronically to arsenic in their drinking water using a novel RT-PCR TaqMan low-density array (TLDA). We found that expression of tumor necrosis factor-α (TNF-α), which activates both inflammation and NF-κB-dependent survival pathways, was strongly associated with water and urinary arsenic levels. Expression of KCNA5, which encodes a potassium ion channel protein, was positively associated with water and toe nail arsenic levels. Expression of 2 and 11 genes were positively associated with nail and urinary arsenic, respectively. Because arsenic exposure has been reported to be associated with long QT intervals and vascular disease in humans, we also used this TLDA for analysis of gene expression in human cardiomyocytes exposed to arsenic in vitro. Expression of the ion-channel genes CACNA1, KCNH2, KCNQ1 and KCNE1 were down-regulated by 1-mM arsenic. Alteration of some common pathways, including those involved in oxidative stress, inflammatory signaling, and ion-channel function, may underlay the seemingly disparate array of arsenic-associated diseases, such as cancer, cardiovascular disease, and diabetes.
DedA Protein Relates to Action-Mechanism of Halicyclamine A, a Marine Spongean Macrocyclic Alkaloid, as an Anti-dormant Mycobacterial Substance
Authors: Arai Masayoshi , Liu Liu , Fujimoto Takao , Setiawan Andi , Kobayashi Motomasa
Published: June 2011

A macrocyclic alkaloid, halicyclamine A, was re-discovered from an Indonesian marine sponge of Haliclona sp. 05A08 as an anti-dormant mycobacterial substance. To clarify action-mechanism of halicyclamine A, halicyclamine A-resistant strains were screened from the transformants of Mycobacterium smegmatis with the genomic DNA library of M. bovis BCG, which were constructed in the multi-copy shuttle cosmid pYUB145. Sequencing analysis of the cosmids isolated from the halicyclamine A-resistant transformants revealed that the responsible gene was involved in the genome region between 2920.549 kb and 2933.210 kb. Further experiments using the transformants over-expressing individual gene contained in the responsible region were executed, and the transformant, which over-expressed BCG2664 gene assigned as dedA gene, was found to become halicyclamine A-resistant. This evidence strongly suggested that DedA protein correlates with the action-mechanism of halicyclamine A as an anti-dormant mycobacterial substance.
Screening for Thyroid Dysfunction in Pregnancy: Is It Worthwhile?
Authors: Lazarus John H.
Published: June 2011

There is a high incidence of thyroid dysfunction during pregnancy resulting in adverse maternal (miscarriages, anaemia in pregnancy, preeclampsia, abruptio placenta and post-partum haemorrhage) and fetal effects (premature birth, low birth weight, increased neonatal respiratory distress) which may justify screening for thyroid function during early pregnancy with interventional levothyroxine therapy for thyroid hypofunction. There is a greater prevalence of subclinical hypothyroidism in women with delivery before 32 weeks and there is even an association between thyroid autoimmunity and adverse obstetric outcome, which is independent of thyroid function. Higher maternal TSH levels even within the normal reference range are associated with an increased risk of miscarriages, fetal and neonatal distress and preterm delivery. There are few prospective randomised trials to substantiate the benefit of screening and the recently reported CATS study did not show a benefit in child IQ at age 3 years. Nevertheless there seems to be a case for screening to prevent adverse obstetric outcomes. The clinical epidemiological evidence base does not justify universal screening at the present time. However, it is probable that more evidence will be produced which may alter this view in the future.
Measurements in the Blood of BDNF for RA Patients and in Response to Anti-TNF Treatment Help Us to Clarify the Magnitude of Centrally Related Pain and to Explain the Relief of This Pain upon Treatment
Authors: Forsgren Sture , Grimsholm Ola , Dalén Tore , Rantapää-Dahlqvist Solbritt
Published: June 2011

Brain-derived neurotrophic factor (BDNF) is a neurotrophin with functions related to neuronal survival/proliferation processes and inflammation. BDNF is also an important central pain mediator. The levels of BDNF have been found to be high for RA patients with severe disease and to become lowered in response to anti-TNF treatment. New information says that the levels of BDNF in the blood parallel the BDNF concentrations in the brain and that BDNF can pass the blood-brain barrier. Furthermore, most of the circulating BDNF is produced in the brain. Habitual and regular exercise, in contrast to temporary exercise, does also lead to a lowering of BDNF blood levels. Both anti-TNF treatment and habitual and regular exercise do have pain-relieving effects. It might be that the pain-relieving effect of anti-TNF treatment is related to an affection of central neuronal regions, hereby influencing BDNF production. Measurements of BDNF in the blood help us to clarify the magnitude of centrally related pain for RA patients and help us to explain the relief of this pain in response to anti-TNF treatment.
Peritoneal Dialysis in Renal Replacement Therapy for Patients with Acute Kidney Injury
Authors: Ansari Naheed
Published: June 2011

Peritoneal dialysis (PD) was the first modality used for renal replacement therapy (RRT) of patients with acute kidney injury (AKI) because of its inherent advantages as compared to Hemodialysis. It provides the nephrologist with nonvascular alternative for renal replacement therapy. It is an inexpensive modality in developing countries and does not require highly trained staff or a complex apparatus. Systemic anticoagulation is not needed, and it can be easily initiated. It can be used as continuous or intermittent procedure and, due to slow fluid and solute removal, helps maintain hemodynamic stability especially in patients admitted to the intensive care unit. PD has been successfully used in AKI involving patients with hemodynamic instability, those at risk of bleeding, and infants and children with AKI or circulatory failure. Newer continuous renal replacement therapies (CRRTs) are being increasingly used in renal replacement therapy of AKI with less use of PD. Results of studies comparing newer modalities of CRRT versus acute peritoneal dialysis have been conflicting. PD is the modality of choice in renal replacement therapy in pediatric patients and in patients with AKI in developing countries.
Hypothyroidism and Thyroid Substitution: Historical Aspects
Authors: Lindholm J. , Laurberg P.
Published: June 2011

The last part of the 19th century was a period of great achievements in medicine and endocrinology. The thyroid gland evolved from being considered a rudimentary structure to an organ related to specific diseases. The singular importance of iodine became acknowledged. Graves-Basedow's disease was described. Surgical treatment evolved with extraordinary speed. Theodor Kocher observed that the clinical picture in patients after total thyroidectomy was similar to the one seen in cretinism. In 1850, the first case of hypothyroidism or myxedema was described. Less than 50 years later, effective treatment was introduced. Another 50 years later, autoimmune thyroiditis was ascertained as the most frequent cause of hypothyroidism (in areas with no iodine deficiency). This paper gives a short survey of the history of hypothyroidism and its treatment.
Azathioprine and Infliximab: Monotherapy or Combination Therapy in the Treatment of Crohn's Disease
Authors: Love Bryan L. , Smith Lisa S. , Sarbah Steedman A. , Fowler Fred C.
Published: June 2011

Crohn's disease is a chronic inflammatory disease of the gastrointestinal tract often resulting in complications resulting in decreased quality of life. Several classes of medications are available to clinicians including mesalamine, budesonide, systemic corticosteroids, thiopurine derivatives, and monoclonal antibodies which target tumor necrosis factor (TNF). Guidelines generally recommend reserving TNF-antagonists for patients who have failed other first-line therapies; however, emerging data suggests there may be some benefit in combining TNF-antagonists, specifically infliximab, with azathioprine. The purpose of this review is to compare the benefits and risks of combination therapy, and identify patients who may benefit most from this approach.
An Onofri-type Inequality on the Sphere with Two Conical Singularities
Authors: Zhou Chunqin
Published: June 2011

In this paper, we give a new proof of the Onofri-type inequality

on the sphere S with Gaussian curvature 1 and with conical singularities divisor for β ∈ (–1, 0); here p1 and p2 are antipodal.
Hot Corrosion of Nimonic 105 in Sodium Sulfate-Sodium Chloride Melts
Authors: Sequeira C. A. C. , Hocking M. G.
Published: June 2011

The corrosion behavior of Nimonic 105 in molten Na2SO4, NaCl, and mixtures of these two salts, at 900 C, in laboratory air and under O2 + SO2/SO3 atmospheres has been evaluated by potentiodynamic, potential decay, and free corrosion potential measurements. In addition, the corrosion products were examined using several electron-optical techniques, and by other analytical methods. Pure Na2SO4 in air did not seem to be very corrosive towards Nimonic 105. Addition of NaCl to the molten Na2SO4 resulted in increased dissolution of Nimonic 105, which was in general nonuniform, alloy constituents nickel and cobalt dissolving more than others. Evidence of internal attack and enhancement of dissolution of the Ni alloy by SO3 was significant only when the corrosion conditions were prolonged. In pure NaCl, catastrophic corrosion occurs, which has been attributed to the depletion, dissolution, and vaporization of some alloy species.
Hydrogen Induced Delayed Cracking of Type III Steel Specimens
Authors: Chu Wu-Yang , Hsiao Chi-Mei , Ju Shur-Yahn , Wang Cheng
Published: June 2011

The influence of loading mode on the apparent yield stress, which is the external stress required to cause the local macroscopic plastic deformation, and the possibility of hydrogen induced delayed cracking of Type III specimens are investigated. Results showed that the apparent torsional yield stress of the severly charged Type III specimen did not decrease and hydrogen induced delayed cracking and fracture would not occur on the original crack or notch plane. For a combined Type I + III specimen, the apparent torsional yield stress could be decreased only when KI was so large that hydrogen induced delayed plastic deformation could occur under the action of KI itself. For the charged Type III cracked or notched specimens of ultra high strength steel, the hydrogen induced delayed cracking could occur along the planes inclined at an angle of 135° to the original crack or notch plane after a large enough torque has been sustained for a sufficiently long period of time. This delayed failure was a typical intergranular fracture. A flat shear fracture would be obtained on the original crack or notch plane if the charged Type III specimen was twisted to fracture immediately. For the uncharged or outgased Type III specimen, no delayed cracking or failure occurred even if a maximum torque had sustained for a long time. The interactive energy between shear stress field of the Type III crack and the strain field of an interstitial hydrogen atom is calculated. The result shows that the interactive energy has a minimum value on the planes inclined at an angle of 135° to the original crack or notch plane. Hence, atomic hydrogen will diffuse to and be enriched in these planes and hydrogen induced delayed cracking and fracture will occur along these planes when the concentration of hydrogen in these planes reaches a critical value.
The Effect of Nickel on Hydrogen Cracking Resistance in Low Alloy Steels—A Review
Authors: Craig Bruce D.
Published: June 2011

Literature is reviewed on the effect of nickel in low alloy steels on their resistance to hydrogen stress cracking. The greatest portion of literature pertains to H2S environments since there is a controversy in the petroleum industry as to the effect of Ni. Addition of greater than 1 % Ni to carbon and low alloy steels is considered to be either detrimental or of no effect in an alloy's resistance to hydrogen stress cracking. This review should provide a starting point from which more organized studies can be performed to evaluate the true effect of Ni on hydrogen cracking resistance.
Sensitization of Austenitic Stainless Steels, I. Controlled Purity Alloys
Authors: Briant C. L. , Mulford R. A. , Hall E. L.
Published: June 2011

This paper presents a study of the effects of carbon, nitrogen, molybdenum, and manganese on the sensitization of high-purity austenitic stainless steels of composition similar to Type 304. The modified Strauss test (ASTM-A262-E), the oxalic acid etch test (ASTM-A262A) and analytical electron microscopy were used to determine the degree and nature of sensitization in the steels. The alloy compositions are considered in terms of effective chromium content, and from plots of this parameter versus sensitization time a strong effect of carbon content is seen. Additions of nitrogen, molybdenum, and manganese are found to delay sensitization at any given carbon concentration. In the case of nitrogen, the amount of improvement depends on both the carbon content and the sensitization temperature. Strong evidence is presented that nitrogen acts to retard the nucleation and/or growth of carbides at grain boundaries and hence increase the time necessary for sensitization. Molybdenum appears to increase the ease with which the steel passivates; thus more chromium depletion is required before sensitization will be detected. The combination of molybdenum plus nitrogen is found to be particularly effective in retarding nucleation and/or growth of carbides; molybdenum alone does not have this effect. Only limited experimental evidence is presented concerning the role of manganese. Beneficial effects of this element are primarily seen at low sensitizing temperatures, where manganese assists nitrogen in slowing carbide formation.
Electrochemical Behavior of Steel in Concrete as a Result of Chloride Diffusion into Concrete: Part 2
Authors: Dehghanian Changiz , Locke Carl E.
Published: June 2011

Penetration of chloride salts into concrete from sources such as deicing-salts or sea water causes a severe corrosion problem to reinforcing steel.

In this paper, the effect of salt penetration into concrete on the corrosion process was investigated by electrochemical techniques such as anodic and cathodic polarization. The potential measurements of steel in concrete were also made to compare the data with the results obtained from the polarization curves.

Concretes made of Type I and Type V Portland cement were used. It was found that corrosion of steel in Type I Portland cement concrete is more rapid than in the Type V Portland cement concrete when the steel is exposed to salt solutions. This may be due to the differences in alkalinites which exist between the Types I and V Portland cement, whereas steel in the concrete with high pH can tolerate more Cl− than in concrete with lower pH.

Corrosion of steel is more severe in the presence of chlorides added externally to hardened concrete than in the presence of chloride mixed with fresh concrete.

Anodic and cathodic current densities for steel in concrete made of Types I and V Portland cement increase with the time that the concrete remains in the salt solutions.
Examination of Passive Films on Iron-Nickel Alloys by Auger Electron Spectroscopy
Authors: Burstein G. T.
Published: June 2011

Detailed analysis of anodic films formed on amorphous iron-nickel alloys containing phosphorus, boron, and molybdenum has been performed by Auger electron spectroscopy. These films contain considerable quantities of P and B both of which are highest at the metal/film interface. Phosphorus accumulates on the metal side of the interface while boron accumulates on the film side, with continuous variation throughout the film thickness. In the film phase, phosphorus shows complex oxidation states. Molybdenum is also found in the films at low concentrations. Polarization curves show that these alloys exhibit greater passivity in 1M HCl than a comparable polycrystalline iron-nickel alloy.
A Study of the Inhibiting Action of Benzene Thiols and Related Compounds on the Corrosion of Zinc in Acidic Media
Authors: Abdel Aal M. S. , Abdel Wahab A. A. , Saied A. El
Published: June 2011

The effect of benzenethiol and its methyl, amino, and carboxylic ring substituted derivatives, benzylthiol and thioglycollic acid on the electrochemical and corrosion behavior of zinc in CH3COOH, H2SO4, and HCl solutions was studied using the galvanostatic technique. In CH3COOH, compounds which function by an adsorption mechanism were found to have inhibitive effects on the corrosion of zinc, while those functioning by surface chelation were ineffective. In H2SO4 and HCl, with the exception of o-methylbenzenethiol (H2SO4 and HCl) and benzylthiol (H2SO4), all investigated compounds were found to accelerate zinc dissolution. Adsorption of the inhibitors followed the Langmuir isotherm, and the mechanism of both the hydrogen evolution reaction and zinc dissolution were found to be the same in the uninhibited and inhibited states.
Stress Corrosion Cracking of Alloy 600 Using the Constant Strain Rate Test
Authors: Bulischeck T. S. , Rooyen D. Van
Published: June 2011

Nuclear grade production tubing of Alloy 600 was evaluated for stress corrosion cracking (SCC) susceptibility in high purity water at 365, 345, 325, and 290 C. Reverse tube U-bend specimens provided crack initiation data and constant extension rate tests were employed to determine the crack velocities experienced in the crack propagation stage. Initial results indicate that a linear extrapolation of data received from high temperature tests can be used to predict the service life of steam generator tubing that has been plastically deformed or is continually deforming by “denting.”
The Oxidation of a Monophase Co-8.03 Wt% Cu Alloy at 700 to 1000 C
Authors: Viani F. , Gesmundo F.
Published: June 2011

The oxidation of a monophase cobalt-copper alloy at high temperature has been Studied to examine the effect of the copper addition to cobalt on the oxidation kinetics as well as on the scale morphology and composition. The rate law remains parabolic as for pure cobalt but the rate constant is higher at all temperatures. This result is interpreted as being due mainly to the doping of CoO by monovalent copper ions by means of a detailed calculation of the rate constant for the alloy making use of the experimental profile of the copper concentration in the scale and of a suitable model for the defect structure of cobalt oxide.
The Effects of Alloying Additions to Ferritic Steels upon Stress Corrosion Cracking Resistance
Authors: Parkins R. N. , Slattery P. W. , Poulson B. S.
Published: June 2011

The effects of Al, Cr, Cu, Ni, Mo, Si, and Ti additions in varying amounts to ferritic steels upon the stress corrosion cracking susceptibilities in a nitrate, a hydroxide, and a carbonate-bicarbonate solution have been determined for the steels in the annealed condition. The effects of the alloying additions vary with the environment, but Cr and Ti, in sufficient amounts, most frequently produced improvements in cracking resistance in the different solutions. The influences of the various alloying additions are mostly dependent upon their effects on dissolution and passivation characteristics, although their effects upon carbon distribution in the steel and mechanical properties are also of importance.
Calculations of Oxidation Rates of Zirconium
Authors: Condon J. B.
Published: June 2011

The rates of oxidation for zirconium metal in oxygen are calculated using perfusive-precipitation modeling with the boundary conditions that: (1) there is no moving boundary and (2) metal matrix saturation is reached for oxygen solubility. The perfursive-precipitation model is a diffusion model with a chemical reaction. It uses Fick's Second Law of Diffusion with an added sink term. The sink term is an overall second order reaction, first order with respect to each the dissolved oxygen and the metal. The stationary boundary condition is valid for the ductile zirconium as long as the expansion due to the reaction product formation does not cause metal failure or spalling. The metal matrix saturated condition implies an upper limit to the metastable solubility of oxygen in the zirconium metal and is approximated from the phase diagram. The calculated rates are compared to the rates listed in the literature. These calculated rates, using no variable parameters, are in good agreement with experimental data.
Comparative Electron Microscopy (SEM) Examination of Fe, Au, and Zn Electrode Surfaces Polarized in Different Regions of Potentiostatic E/I Behavior
Authors: Podestá J. J. , Piatti R. C. V. , Arvia A. J.
Published: June 2011

The surface morphology of some metals (Fe, Au, and Zn) after potentiostatic polarization was studied through SEM examination. The following electrochemical systems were investigated at 25 C: (1)Fe/1 M H2SO4; (2) Au/1 M HCl; and (3) Zn/2 M NaOH. The polarization potentials were chosen in the active dissolution region, in the passivity region, and in the potential range where periodic oscillations of the anode current are observed. The changes in the morphologies of attack on the various metals were related to the film forming species and of anion adsorption.
The Stress Corrosion Cracking of Sensitized Stainless Steel in Thiosulfate Solutions
Authors: Isaacs H. S. , Vyas B. , Kendig M. W.
Published: June 2011

The stress corrosion cracking (SCC) of sensitized Type 304 stainless steel in thiosulfate solutions has been studied using constant extension rate tests. Very low concentrations of about 6.10−7M Na2S2O3 (0.1 ppm) gave cracking. With boric acid added, higher concentrations (1 ppm) were required. The SCC was shown to be electrochemically controlled. Below −0.5 VSCE (−0.75SHE) no SCC took place; above this potential, the rate of SCC increased with potential. Straining was required before SCC continued at 0.5 V if the potential was held at or below −0.5 V for extended times.
Discussion:
The Significance of External Polarization on Stress Corrosion Crack Growth by Anodic Dissolution
Authors: Poulson Bryan
Published: June 2011

The following is a discussion of the article entitled “The Significance of External Polarization on Stress Corrosion Crack Growth by Anodic Polarization” by P. Doig and P. E. J. Flewitt, published in Corrosion, Vol. 37, p. 378 (1981) July.
Effect of Hydrogen on the Apparent Yield Stress—Research on the Cause of Hydrogen Induced Delayed Plasticity
Authors: Chu Wu-Yang , Li Shi-Qun , Hsiao Chi-Mei , Ju Shur-Yahn
Published: June 2011

The effect of hydrogen on the apparent yield stress, which is a necessary exterior stress to cause the local macroscopic plastic deformation, was investigated for various carbon and low alloy steels with a wide range of tensile strength. Smooth tensile, bent beam, and precracked WOL specimens were used. The results show that the effect of hydrogen on the yield strength of a smooth tensile specimen is insignificant. However, for the smooth bent beam or precracked specimens with a stress gradient, hydrogen decreases the apparent yield stress considerably if the strength of steel and the amount of hydrogen entering into the specimen exceed critical values. This is the cause of hydrogen induced delayed plastic deformation and then hydrogen induced delayed cracking. The apparent yield stress of the charged specimen decreases with increasing tensile strength and the amount of hydrogen in the steel. It depends evidently on the strain rate and test temperature and is reversible, but is not related to the prestrain condition. The variation of the apparent yield stress of the charged specimens with the test temperature is not monotonous, there is a minimum near room temperature. According to these results, a possible mechanism of hydrogen induced apparent yield stress reduction has been suggested.
Numerical Determination of Potential Distributions and Current Densities in Multi-Electrode Systems
Authors: Helle H. P. E. , Beek G. H. M. , Ligtelijn J. Th
Published: June 2011

Two numerical solution methods of the Laplacian equations, within boundary conditions set by the geometries and electrode reactions of arbitrary cells, are presented. One method is based on the location of current sources on suitable locations in and around the cell. The strength of these sources is a variable. With the solution of the equations of the potential gradients at the boundaries, the strength of the sources is determined, and herewith potentials and current densities. In the second method, the potential distribution is determined by solution of the equations obtained with a finite element discretisation of the cell. Compatibility with the potential dependant boundary conditions at the electrode surfaces is reached, for both methods, with an iteration procedure. Both methods are used for the solution of a problem for which an analytical solution is available. Some conclusions regarding their applicability are drawn, and an example of the use of this method on the problem of the galvanic corrosion for a ship/propeller/sea water system is given.
Electrochemical Etching of Copper Ion Implanted H-19 Aluminum in Aqueous Chloride/Sulfate Solution at 95 C
Authors: Florio S. M. , Moore W. M. , Hutchins G. A. , Summers S. E.
Published: June 2011

Electrochemical etching experiments were conducted with Cu ion implanted H-19 Al foil in aqueous NaCl/Na2SO4 solution at 95 C in an effort to improve the procedure for the surface area enhancement of Al. The concentration of Cu in unimplanted and implanted specimens was determined by electron probe microanalysis. An amorphous passive film on the order of 200 A˚ thick formed on the Al surface in the 95 C etch solution prior to the electrochemical etch. A model for the etch process in which pits were seen to propagate immediately at flaws in this passive surface was supported by the shape and distribution of etch pits after brief etching. Pits propagated under the surface oxide in crystallographically determined directions in both unimplanted and Cu implanted samples. The presence of ion implanted Cu resulted in a smaller number of more highly developed, deeper pits. Capacitance versus voltage and weight loss measurements of highly etched samples indicated that approximately the same amount of overall Al dissolution occurred in all samples. More local etching occurred in the high dose Cu implanted specimens, with significant loss of fine surface structure. Electron probe measurements showed that no change in the total Cu content of the various foils occurred during etching.
Discussion:
Deposition Rate of Suspended Hematite in a Boiling Water System under BWR Conditions
Authors: Cohen Paul
Published: June 2011

The following is a discussion of the article, “Deposition Rate of Suspended Hematite in a Boiling Water System under BWR Conditions,” by T. Mizuno, K. Wada, and T. Iwahori, published in Corrosion, Vol. 38, p. 15 (1982) January.
Discussion:
The Study of Inhibitors for Sour Gas Service
Authors: Blair C. M.
Published: June 2011

The following is a discussion of the article entitled “The Study of Inhibitors for Sour Gas Service” by K. Suzuki, T. Kouno, E. Sato, and T. Murato, published in Corrosion, Vol. 38, No. 7, p. 384 (1982).
Induction Time Studies of Fe18Cr and 430 SS under Open Circuit Conditions in Chloride-Containing Sulfuric Acid
Authors: Covino B. S. , Rosen M.
Published: June 2011

In order to promote the effective and efficient application of corrosion resistant metals and alloys in mineral processing environments, the Bureau of Mines, U.S. Department of the Interior, has characterized the effect of aggressive ions on the corrosion and passive behavior of two stainless steels, Fe18Cr and AISI 430 SS. Samples prepassivated in oxygen saturated 1 N H2SO4 at 0.6 V NHE and then released to open circuit and aged for times ranging from 10 min to 80,000 min (55 days), were subsequently exposed to chloride ion concentrations ranging from 5 to 44 parts per thousand (ppt). Susceptibility to chloride ion attack was determined as a function of time in solution (film aging time), chloride ion concentration [Cl−], and open circuit potentials (E) at the time chloride was added by measuring the amount of time (induction time, t) required for a sample to begin corroding after adding the chloride ion. The experimentally determined induction times were fitted to an equation of the form: 1/t=K Em[Cl−]n where K, m, and n are empirically determined constants. Results obtained for short (<100 min) aging times were different from those for long (100 to 80,000 min) aging times. For Fe18Cr exposed for short film aging times prior to addition of the chloride, larger [Cl−] resulted in shorter induction times, and higher values of E resulted in longer induction times. For 430 SS exposed for short film aging times, and for 430 SS and Fe18Cr exposed for longer film aging times prior to addition of chloride ions, both larger [Cl−] and higher values of E resulted in shorter induction times.
Effect of Solidification Structure of the Alloy Cu-10% Al-1% Fe on Its Corrosion and Mechanical Properties
Authors: Vergara Victor , Matamala Guillermo , Moreno Aldo
Published: June 2011

An 89% Cu, 10% Al, 1% Fe alloy was solidified under different cooling conditions in order to obtain different kinds of dendritic structures. The main structural difference observed was the grain size, which varied from 0.017 to 0.57 grains/mm2. The mechanical behavior was determined by tension and hardness test. The fracture surface and microstructure were observed by means of scanning electron microscopy. Other samples were subjected to corrosion tests in a saline solution of a concentration similar to that of seawater; these tests were potentiodynamic and potentiostatic during twelve hours at −50 mV (ECS). The electrolytic solutions were analyzed by atomic absorption spectrophotometry to determine the Cu, Al, and Fe concentrations.

The tension and hardness tests did not show a significant correlation. The corrosion tests showed a different amount of corrosion, which depends primarily on the morphology and type of solidification structure. Higher dealuminization was found in samples with higher content of γ2 phase. The columnar grain structure showed a lower selective corrosion than the equiaxial structure.

A fine dispersion of the α + β phase in relation to the α+γ2 matrix enhances the dealuminization of the alloy.
The Anodic Polarization Characteristics of Fe-Si-Al Alloys in 1N H2SO4
Authors: Wakefield Sandra , Beck Franklin H. , Powell Gordon W.
Published: June 2011

The anodic polarization characteristics in 1N H2SO4 (25 C) of Fe-8 Wt% Si, Fe-8Al and Fe-5Si-3Al alloys fabricated by conventional processing (ingot metallurgy) and of Fe-8Al fabricated by powder metallurgy were determined. With the exception of the Fe-8Si, the alloys undergo an active-to-passive transition. The passivation behavior is controlled by the aluminum content of the alloys, the aluminum decreasing the passivation potential. Although the appearance of the corrosion attack is different, the anodic polarization characteristics of the Fe-8Al alloy are essentially independent of the method of fabrication (i.e., ingot metallurgy vs powder metallurgy).
A Microstructural Study of the Sulfide Stress Cracking Resistance of a Cr-Mo-V-B Steel
Authors: Shei S. A. , Kim C. D.
Published: June 2011

A study was conducted to determine the effect of microstructure and strength level on the sulfide stress cracking (SSC) performance of a Cr-Mo-V-B steel. The steel was heat treated by quenching and tempering in a temperature range of 1100 to 1325 F (593 to 718 C). Crack initiation and propagation behaviors were examined using three-point bending tests. The experimental results showed that an increase in tempering temperature was associated with an increase in crack initiation time, indicating an increase in SSC resistance. The increased tempering temperature also changed the crack propagation path from a mixture of transgranular and intergranular to primarily transgranular cracking. Crack initiation and propagation were shown to be associated with decohesion and/or microvoid formation at carbide/matrix and inclusion/matrix interfaces. Differences in the SSC resistance were correlated with the morphology of carbide particles.
The Effect of Pollutants and Bacterial Microfouling on the Corrosion of Copper Base Alloys in Seawater
Authors: Schiffrin D. J. , De Sanchez S. R.
Published: June 2011

The effects of seawater contaminants such as ammonium and sulfide ions and trimethylamine on the corrosion behavior of copper base alloys have been studied. Sulfide contamination causes a long-term change in the surface properties of the passive film formed on these alloys in uncontaminated seawater. The kinetics of oxygen reduction and anodic dissolution were studied, and the results were analyzed on the basis of a simple, activated-diffusionally controlled model. It has been shown that the relationships derived for the rotating disk electrode geometry can be extended to any hydrodynamic configuration, provided the corresponding dimensionless number relationships are known. The correlating parameter (between the rotating disk experiments and hydrodynamic geometries) used in this work is the mass transfer coefficient. Bacterial contamination led to the loss of passivation, and the corrosion rate was determined by the rate of oxygen diffusion through the bacterial slime. Three genera of bacteria have been identified in the bacterial slimes present in condenser tubes using contaminated seawater as coolant. These were Pseudomonas, Micrococcus, and Corynebacterium. Of these, the Pseudomonas were entirely responsible for the observed corrosion rate increase. The combination of bacterial contamination and anaerobic conditions can create an extremely corrosive environment.
The Chemistry of Azole Copper Corrosion Inhibitors in Cooling Waters
Authors: Hollander Orin , May Roger C.
Published: June 2011

Although benzotriazole and tolyltriazole are well known as extremely effective inhibitors of copper corrosion, very little has been reported in the literature regarding their chemistry, particularly in near neutral, low conductivity aqueous media. The behavior of these inhibitors was studied under typical cooling water conditions. Relationships between chemical properties and inhibition behavior are discussed. A modified theory of the mechanism of inhibition is proposed.
Monitoring pH and Corrosion Potentials in High Temperature Aqueous Environments
Authors: Niedrach Leonard W. , Stoddard William H.
Published: June 2011

A zirconia membrane electrode that responds to pH can serve admirably as a pH sensor in high temperature aqueous systems. Alternatively, under conditions of known, stable pH, the sensor may be used as a reference electrode for monitoring corrosion and redox potentials. Data are presented to illustrate the thermodynamic reliability and stability of such a sensor at elevated temperatures. An example of corrosion potential monitoring, including correlations with related ambient temperature measurements of pH, oxygen and hydrogen concentrations, and water resistivity, is given.
Theory of Dielectric Properties of Heterogeneous Substances Applied to Water in a Paint Film
Authors: Lindqvist S. A.
Published: June 2011

The water content of 12 paints on steel substrate, exposed to 0.1M sodium chloride at 25 C for 24 h, was calculated from impedance measurements and compared with gravimetric determinations. Brasher's empirical expression was compared with five mixture formulas derived from the theory of dielectric properties of heterogeneous substances by Boettcher, Bruggeman, Looyenga, Wagner, and Rayleigh. The 12 paints were based on two grades of red lead and iron oxide in epoxy, chlorinated rubber, alkyd, and linseed oil binders.

The significance of the results for cyclic wet/dry paint tests according to (1) the difference between the water absorption and desorption rates of a single paint and (2) the testing of different types of paints in the same cycle test program are exemplified. A possible explanation is given for the poor correlation often found between the results of cyclic wet/dry tests and those obtained in practical applications.
Stress Corrosion Cracking of 13Cr Steels in CO2-H2S-Cl− Environments
Authors: Kurahashi H. , Kurisu T. , Sone Y. , Wada K. , Nakai Y.
Published: June 2011

Stress corrosion cracking (SCC) behavior of two 13Cr steels was investigated in aqueous CO2-H2S environments. U-bend tests, constant load tensile tests, and corrosion tests were performed in CO2 environments containing different amounts of H2S. In addition, the slow strain rate tensile (SSRT) tests and hydrogen absorption measurements were done under cathodic hydrogen charging conditions to determine why 13Cr steels are more susceptible to SCC in H2S environments than low alloy steels are.

The 13Cr steels were less resistant to SCC in the CO2-H2S environments than low alloy steels were, but some 13Cr steels were not subject to SCC even at a hydrogen sulfide partial pressure of 0.3 atm. Furthermore, it was found that SCC in a CO2-H2S environment was caused by hydrogen embrittlement and that the SCC susceptibility of 13Cr steels was affected by their intergranular cracking behavior. Thus, their microstructures and carbide dispersions are important factors in defining SCC susceptibility of 13Cr steels.
Properties of Nitrogen-Containing Stainless Alloy Designed for High Resistance to Pitting
Authors: Bandy R. , Rooyen D. Van
Published: June 2011

This paper describes the following features of a recently developed high nitrogen-bearing, highly corrosion resistant stainless steel: tensile properties, stress corrosion characteristics in boiling magnesium chloride solution, effect of sensitizing heat treatment on the nature and extent of grain boundary attack, and electrochemical polarization behavior in sulfuric acid and low pH chloride solutions.
The Environmental Cracking of Ticode-12® in Aqueous Chloride Environments
Authors: Sorensen N. R. , Ruppen J. A.
Published: June 2011

The slow strain rate technique (SSRT) was used to assess the environmental cracking behavior of TiCode-12, a titanium-base alloy, in a simulated repository brine. The hydrogen effects and electrode potential were examined to understand the alloy's hydrogen embrittlement (HE) and stress corrosion cracking (SCC) behavior. At open circuit, no environment effect was noted, as the results in air and brine were essentially identical. Hydrogen precharging of the samples resulted in a microstructure change, and at very high hydrogen levels, a degradation in mechanical properties. Anodic polarization of the Grade 12 Ti had no effect on mechanical properties, again indicating that the alloy is not susceptible to SCC. Severe cathodic polarization results in a change in both fracture mode and macroscopic stress-strain behavior. However, the conditions under which these changes were observed are considered to be much more severe than those encountered in the proposed repository sites.
Stress Corrosion Behavior of AISI 304 Stainless Steel in a Boiling 42% MgCl2 Solution under Cyclic Slow Strain Rate Technique
Authors: Nakayama T. , Takano M.
Published: June 2011

Stress corrosion cracking (SCC) behavior of AISI 304 stainless steel (SS) rod and plate specimens in boiling 42% MgCl2 was investigated using a monotonic and a cyclic slow strain rate technique (SSRT) in the crosshead speed (CHS) range from 6×10−5 to 1.5 mm/min. A maximum stress (σmax) of 50 to 330 MPa was selected in a cyclic slow strain rate test. A thermal cyclic stress test was also conducted in the solution. Fracture surface observations revealed that crack mode changed from transgranular to intergranular with increasing stress level in the SCC process, and the crack mode was independent of the CHS change. Time to failure in the cyclic slow strain rate test was constant at a given σmax in all CHS used (except slow CHS of 6×10−5 at σmax of 50 MPa). Crack propagation rate (da/dt) increased with the stress intensity factor, and it was independent of CHS. The corrosion potential varied with the stress cycle after cracking started; this indicated that SCC proceeded by a dissolution-repassivation mechanism. The cyclic slow strain rate test is recommended as an SCC test that can reproduce the actual service conditions of stress.
Discussion:
The Existence of Imidazoline Corrosion Inhibitors
Authors: Blair Charles M.
Published: June 2011

The following is a discussion of the article entitled “The Existence of Imidazoline Corrosion Inhibitors,” by J. A. Martin and F. W. Valone, published in Corrosion, Vol. 41, No. 5, p. 281, 1985.
Corrosion of Galvanized and Galvannealed Steel in Solutions of pH 9.0 to 14.0
Authors: Sergi G. , Short N. R. , Page C. L.
Published: June 2011

Well-characterized zinc coatings on steel have been prepared so that either the eta or zeta phase was present as the outermost layer. Their electrochemical behavior was studied in a range of solutions by galvanostatic anodic polarization and potentiodynamic anodic polarization scans. The corrosion products were identified using scanning electron microscopy (SEM) and x-ray analysis. Results show that the solution pH has the most marked effect on electrochemical behavior and the nature of the corrosion product formed. At a given solution pH, the behavior and products formed are modified according to the concentration of chloride in the solution and the type of iron-zinc alloy layer investigated. The results are discussed in relation to the practical use of galvanized reinforcement in concrete.
Mechanistic Aspects of Pit Growth on Nickel in Diluted Chloride Solutions
Authors: Heimgartner P. , Bohni H.
Published: June 2011

Pit current densities (CDs) in small pits have been found to be potential dependent, indicating an ohmic or mixed ohmic-charge transfer controlled dissolution mechanism. In a later stage of pit growth, a diffusion-controlled dissolution has often been reported. The potential-dependent mechanism is not always restricted to only the beginning of pit development, as has been shown in galvanostatic tests with rather low CDs.

In this paper, the mechanism change from ohmic-charge transfer to diffusion-controlled pit growth was also studied in potentiostatic experiments by means of potential pulses added to the applied potential. The current response to fast potential changes differs for the two mechanisms.

The influence of a number of parameters [such as potential, position of the specimen (horizontal or vertical), agitation of the bulk electrolyte, and pit diameter] on the transition time for mechanism change could be investigated using this pulse technique.

Results also show that the rate law for pit growth can be very similar for the two types of mechanisms and different pit geometry (artificial pits of the wire type or “naturally” growing pits).
Technical Note:
On the Effects of Magnesium on the Atmospheric Corrosion Resistance of Galvanized Sheet Steel
Authors: Townsend H. E.
Published: June 2011

The corrosion resistance of sheet steel with galvanized coatings containing 0.04 wt% magnesium was compared to that of conventional galvanized sheet without magnesium additions. No significant differences in the long-term durabilities of these coatings were detected in atmospheric corrosion tests conducted in severe or moderate marine, rural, or industrial environments. It is concluded that, at the level tested, magnesium has no effect on the life of galvanized coatings.
Effect of Chromate Inhibitor on the Mechanical and Electrochemical Components of Erosion-Corrosion in Aqueous Slurries of Sand
Authors: Postlethwaite John
Published: June 2011

Both weight loss and electrochemical measurements have been made to study the effects of chromate inhibitor on the erosion-corrosion of carbon steel specimens in a 5 cm diameter slurry pipeline carrying a 20 Vol% aqueous slurry of silica sand (size range 0.3 to 0.6 mm) over a velocity range 2–3.5 m/s. In the absence of inhibitors the total wear rate of a 5 cm long × 1 cm wide specimen located at the 4 o'clock position in the pipe wall was 2.7 to 17.5 mm/year. In the presence of inhibitor, the wear rate was reduced to values in the range 0.48 to 0.82 mm/year. The electrochemical measurements showed that erosion was the major mode of metal loss. However, there is a major interaction between the erosion and the corrosion components and a reduction in the corrosion component, which leads to much smoother surfaces, greatly reduced the erosion losses.
Surface Characteristics of Cold-Rolled Steel as They Affect Paint Performance
Authors: Iezzi Robert A. , Leidheiser H.
Published: June 2011

Paint failure on cold-rolled steel sheet occurs by cathodic delamination at the pretreatment/steel interface. Surface contamination, mainly carbon, is primarily responsible for variable paint performance on cold-rolled steel. The carbon is not uniformly distributed on the steel surface, and its presence in localized areas interferes with the formation of the zinc phosphate during the pretreatment step. The carbon is present primarily in amorphous elemental form and probably originates during annealing from the breakdown of residual rolling oils left on the steel surface prior to annealing and from the thermal dissociation of carbon monoxide. Material with high surface contamination fails much more rapidly than material with low surface contamination because of the poorer bonding of the zinc phosphate to the substrate and the greater oxygen and moisture access to the steel surface as a consequence of porosity of the zinc phosphate layer.