bluuebunny/crossref_metadata_2025 huggingface dataset:
A Partitioned Formulation for FEM/BEM Coupling in Contact Problems Using Localized Lagrange Multipliers
Authors: González Jose A. , Park K.C. , Abascal Ramon
Published: July 2014

This paper presents a state-of-the-art in the use of localized Lagrange multipliers (LLMs)for 3D frictional contact problems coupling the Finite Element Method (FEM) and the BoundaryElement Method (BEM). Resolution methods for the contact problem between non-matching mesheshave traditionally been based on a direct coupling of the contacting solids using classical Lagrangemultipliers. These methods tend to generate strongly coupled systems that require a deep knowledgeof the discretization characteristics on each side of the contact zone complicating the process ofmixing different numerical techniques. In this work a displacement contact frame is inserted betweenthe FE and BE interface meshes, discretized and ﬁnally connected to the contacting substructuresusing LLMs collocated at the mesh-interface nodes. This methodology will provide a partitionedformulation which preserves software modularity and facilitates the connection of non-matching FEand BE meshes.
Proposed and Method Presentation of Bridge Model Updating
Authors: Wang De Jun , Feng De Min , Jin Bao
Published: July 2014

This article briefly reviews the two methods of finite element model (FEM) updating, such as direct matrix methods and the sensitivity-based model updating methods. In addition, the problem in bridge structure model updating often needs to solve large-scale ill-posed linear systems. Therefore, two regularization methods of Tikhonov and TSVD were introduced. Meanwhile, for these systems, it is proposed that the application of the two kinds of regularization method to solve the problem which the test data contaminated by noise may rarely lead to a physically meaningful updated model.
A Study on Practical Design in Joint Core Area of Concrete Beam
Authors: Zhao Yang , Chai Ji Yan , Liu Yang
Published: July 2014

This paper makes a comparison between computer and hand computation of joint core area according to an example of typical engineering. Firstly, author summarized the common problems and erroneous judgments which are likely to happen in the software calculation of joint core in engineering design, and then analyzed the causes to these problems, and provided hand calculation solutions to related problems according to standard formulas. Author analyzed and proved that the reinforcement calculation of joint core area for frame structure calculation is not only necessary, but also can conveniently solve the coordination problems in the related terms of “Concrete Structure Design Norm”, “Earthquake Resistant Design Code” and “Concrete Structure Engineering Operation Standard”, and is also the supplement for the uncovered parts of computer calculation.
Some Key Issues and Challenges of Building the Structural Health Monitoring System of Bridges
Authors: Xu Guang Ming , Chen Li , Gao Xin
Published: July 2014

In view of the issue of bridge structure safety, this study pointed out the necessity and urgency to build the bridge safety operational monitoring system. The basic idea, system composition, current situation of the development and application of structural health monitoring system were summarized. Finally, the key problems and development trend of bride safety monitoring were proposed.
Influential Parameter Study on the Main-Cable State of Self-Anchored Suspension Bridge
Authors: Sun Yong Ming , He Xiao Dong , Li Wen Dong
Published: July 2014

This paper made a thorough influencing parameter analysis on the unstressed state and completed state of main cable of self-anchored suspension bridge. The main cable curve, the amount and the action point of the resultant force of main cable on the main saddle were considered as the controlling objectives, the rational completed state of main cable was defined; Wusong bridge in Jilin city was taken as an example, the finite element mode of main cable was created. The unstressed state and the completed state of main cable under different parameters were calculated, and all the results were compared with the reference state, the influences of each parameter deviation on the state of main cable were studied: the self-weight and erection temperature of main cable had little effect on the state of main cable; the length of the mid-span main cable mainly influenced itself line-shape, while the length of the side-span main cable had significant effect on each controlling objective; made the unstressed line-shape of main cable as the controlling condition, the position deviation of the main saddle and back anchorage facet, happened before the main cable erection stage, had little effect on the completed state, but which will have great effect on the completed state when they happened after the main cable erection stage. Engineering example analysis results showed that, the tensile stiffness of main cable and the boom-completed force would have some effect on the completed state of main cable, and the tensile stiffness of main cable and the self-weight of the main beam should be tested before erecting the main cable, in the same time the deviation should be control within the rational limits; recommended that the unstressed shape of main cable should pre-lift, which could counteract the deformation of the main saddle and the back anchorage facet at the completed stage, this conclusion had a strong guiding significance and reference value on the work of constructing the main cable of self-anchored suspension bridge.
Is religious fundamentalism our default spirituality?: Implications for teacher education
Authors: Potgieter Ferdinand J. , Van der Walt Johannes L.
Published: July 2014

Using experiential interpretivism as underpinning methodology, this article investigates whether religious fundamentalism is the default spirituality of human beings. Our research is based on a hermeneutic reconstructive interpretation of religion, fundamentalism, radicalism, extremism, spirituality, life- and worldview, and the role of education in bringing about peaceful coexistence amongst people. We concluded that the natural religious-fundamentalist inclination of the human being tends to be (and needs to be) counterbalanced by the education – that is, socialisation – that he or she receives from the moment of birth, the important first six or seven years of life, and throughout his or her life. Based on this conclusion, the article ends with the articulation of ten implications for teacher education.
Imaging of cartilage repair procedures
Authors: Sanghvi Darshana , Munshi Mihir , Pardiwala Dinshaw
Published: July 2014

The rationale for cartilage repair is to prevent precocious osteoarthritis in untreated focal cartilage injuries in the young and middle-aged population. The gamut of surgical techniques, normal postoperative radiological appearances, and possible complications have been described. An objective method of recording the quality of repair tissue is with the magnetic resonance observation of cartilage repair tissue (MOCART) score. This scoring system evaluates nine parameters that include the extent of defect filling, border zone integration, signal intensity, quality of structure and surface, subchondral bone, subchondral lamina, and records presence or absence of synovitis and adhesions. The five common techniques of cartilage repair currently offered include bone marrow stimulation (microfracture or drilling), mosaicplasty, synthetic resorbable scaffold grafts, osteochondral allograft transplants, and autologous chondrocyte implantation (ACI). Complications of cartilage repair procedures that may be demonstrated on magnetic resonance imaging (MRI) include plug loosening, graft protuberance, graft depression, and collapse in mosaicplasty, graft hypertrophy in ACI, and immune response leading to graft rejection, which is more common with synthetic grafts and cadaveric allografts.
Role of ultrasound in evaluation of peripheral nerves
Authors: Lawande Ashwin D , Warrier Sudhir S , Joshi Mukund S
Published: July 2014

Ultrasonography (USG) is an excellent cost-effective modality in imaging of peripheral nerves. With the newer high-frequency probes with different footprints which allow high-resolution imaging at relatively superficial location, USG can detect and evaluate traumatic, inflammatory, infective, neoplastic, and compressive pathologies of the peripheral nerves. This article describes the technique for evaluation of nerves by USG as well as the USG appearances of normal and diseased peripheral nerves.
Comparison of conventional MRI and MR arthrography in the evaluation of wrist ligament tears: A preliminary experience
Authors: Pahwa Shivani , Srivastava Deep N , Sharma Raju , Gamanagatti Shivanand , Kotwal Prakash P , Sharma Vijay
Published: July 2014

Aims: To compare conventional magnetic resonance imaging (MRI) and direct magnetic resonance (MR) arthrography in the evaluation of triangular fibrocartilage complex (TFCC) and intrinsic wrist ligament tears. Materials and Methods: T1-weighted, fat suppressed (FS) proton density plus T2-weighted (FS PD/T2), 3D multiple-echo data image combination (MEDIC) sequences and direct MR arthrography were performed in 53 patients with wrist pain. Images were evaluated for the presence and location of TFCC, scapholunate ligament (SLL) and lunatotriquetral ligament (LTL) tears, and imaging findings were compared with operative findings in 16 patients who underwent arthroscopy or open surgery (gold standard). Results: Sixteen patients underwent arthroscopy/open surgery: 12 TFCC tears were detected arthroscopically out of which 9 were detected on FS PD/T2 sequence, 10 on MEDIC sequence, and all 12 were detected on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in the detection of TFCC tears were 75%, 83.3%, and 100%, respectively. Out of the eight arthroscopically confirmed SLL tears, three tears were detected on FS PD/T2 sequence, five on MEDIC sequence, and all eight were visualized on MR arthrography. The sensitivities of FS PD/T2, MEDIC sequences, and MR arthrography in detecting SLL tears were 37.5%, 62.5%, and 100%, respectively. One arthroscopically confirmed LTL tear was diagnosed on FS PD/T2 sequence, three on MEDIC sequence, and all five arthroscopically confirmed LTL tears were detected with MR arthrography. The sensitivities of PD, MEDIC sequences, and MR arthrography in detecting LTL tears were 20%, 40%, and 100%, respectively. Conclusions: MR arthrography is the most sensitive and specific imaging modality for the evaluation of wrist ligament tears.
Bone marrow lesions: A systematic diagnostic approach
Authors: Grande Filippo Del , Farahani Sahar J , Carrino John A , Chhabra Avneesh
Published: July 2014

Bone marrow lesions on magnetic resonance (MR) imaging are common and may be seen with various pathologies. The authors outline a systematic diagnostic approach with proposed categorization of various etiologies of bone marrow lesions. Utilization of typical imaging features on conventional MR imaging techniques and other problem-solving techniques, such as chemical shift imaging and diffusion-weighted imaging (DWI), to achieve accurate final diagnosis has been highlighted.
Antral follicle count in normal (fertility-proven) and infertile Indian women
Authors: Agarwal Arjit , Verma Ashish , Agarwal Shubhra , Shukla Ram Chandra , Jain Madhu , Srivastava Arvind
Published: July 2014

Background: Antral follicle count (AFC) has been labeled as the most accurate biomarker to assess female fecundity. Unfortunately, no baseline Indian data exists, and we continue using surrogate values from the Western literature (inferred from studies on women, grossly different than Indian women in morphology and genetic makeup). Aims: (1) To establish the role of AFC as a function of ovarian reserve in fertility-proven and in subfertile Indian women. (2) To establish baseline cut-off AFC values for Indian women. Settings and Design: Prospective observational case-control study. Materials and Methods: Thirty patients undergoing workup for infertility were included and compared to equal number of controls (women with proven fertility). The basal ovarian volume and AFC were measured by endovaginal. USG the relevant clinical data and hormonal assays were charted for every patient. Statistical Analysis Used: SPSS platform was used to perform the Student′s t-test and Mann-Whitney U-test for intergroup comparisons. Correlations were determined by Pearson′s ranked correlation coefficient. Results: Regression analysis revealed the highest correlation of AFC and age in fertile and infertile patients with difference in mean AFC of both the groups. Comparison of the data recorded for cases and controls showed no significant difference in the mean ovarian volume. Conclusions: AFC has the closest association with chronological age in normal and infertile Indian women. The same is lower in infertile women than in matched controls. Baseline and cut-off values in Indian women are lower than that mentioned in the Western literature.
False-positive 111 In-pentetreotide Uptake in Gastritis
Authors: Usmani Sharjeel , Alshammari Alshaima
Published: July 2014

111 In-pentetreotide [ 111 In-octreoscan] is the most widely used radiolabeled somatostatin analog for evaluating neuroendocrine tumor overexpression of somatostatin receptors. False-positives studies of somatostatin receptor scintigraphy have been reported and often the cause is unexplained but assumed to be due to high number of somatostatin receptors in other pathologies. Causes of false-positives include visualization of the gallbladder, nasal mucosa and pulmonary hilar areas in respiratory infections, thyroid abnormalities, accessory spleens, recent Cerebrovascular accidents (CVA′s) and activity at the site of a recent surgical incision. In infection or inflammation the cause of false-positive uptake is probably the result of tracer binding by somatostatin receptors on the inflammatory leukocytes. In this case report, we report, a 44-year-old male patient with false-positive 111 In-pentetreotide uptake due to gastritis.
Corrosion Testing by Measurement of Local Cell Potentials★
Authors: RICE J. K.
Published: July 2014

The method of studying corrosion rates by measuring the local cell potential using a rotating electrode and stationary micro-probe reference electrode is briefly reviewed. The results are presented of applying the method to the study of the effect of different variables on the corrosion inhibition properties of hexametaphosphate on steel in aerated water systems.
Laboratory Measurement of the Corrosion of Ferrous Metals in Soils★
Authors: SCHWERDTFEGER W. J.
Published: July 2014

A method is described for setting up soil-corrosion cells using a soil-wetting procedure that gives reproducible results. By measuring the weight losses on cell electrodes made of steel and of cast iron after exposure to various soils for six months, it was possible to compare the effects of corrosion on the two materials. It was also found that the electrode weight losses correlated with the weight losses and maximum pitting on wrought ferrous specimens exposed for 10 years at the field test sites. Because the laboratory soils covered the range of corrosivity peculiar to soils, it was possible to derive empirical equations for predicting weight loss and pitting at the end of 10 years for presumably any soil. It is also shown how reasonable adjustments can be made for areas other than that of the field specimens and for exposure periods other than 10 years.
Corrosion Resistance of Cupronickel Alloys Containing 10 to 30 Percent Nickel★
Authors: LaQUE FRANK L.
Published: July 2014

Because there has been a gradual extension to industries other than the power generation industry of the use of cupronickel alloys containing 10 to 30 percent nickel the author considers it pertinent to provide information on their resistance to corrosives other than cooling waters. This is needed because the alloys' use in heat exchanger tubes in applications where one side is exposed to various corrosives at high temperatures makes their reaction to the product side corrosive as significant as the attack on the water side.

After outlining the basic homogeneous character of the copper-nickel alloys, the author discusses the theoretical aspects of their corrosion characteristics. Tables and figures outline results of certain tests of the alloys under various stresses and exposed to various environments.

Data collected on performance in specific service are then appended, principally in the form of tabulated information, on waters other than salt waters, ammoniacal solutions, brines, alkaline solutions, petroleum products containing hydrogen sulfide, miscellaneous petroleum products, organic compounds, chlorinated solvents, sulfuric acid, halogens and halogen compounds, paper stock suspensions. 19 references, 5 figures, 15 tables.
Measurement of the Susceptibility Of Galvanized Surfaces To Humid Storage Stain
Authors: NEISH R. A.
Published: July 2014

Rapid steam tests and a water-film test have been developed for evaluating the resistance of galvanized surfaces to “humid-storage stain.” The methods presented in this paper are believed to be practical for mill control or for investigation of protective films. The necessary apparatus and procedures are described.
Sea Water Immersion Trials Of Protective Coatings
Authors: GREENBLATT J. H.
Published: July 2014

Sea water immersion trials of a variety of types of underwater compositions have shown the superior performance of vinyl finishes, both as protective and antifouling paints. Panel tests have shown that vinyl finishes can be used on cathodically protected hulls and shipboard trials have substantiated this, provided that a controlled cathodic protection system is used.
Relation of Corrosion to Business Costs★
Authors: WACHTER AARON
Published: July 2014

Every business can benefit from reduction of its losses due to corrosion. Awareness of all possible sources of such losses is essential. Unnecessary acceptance of losses is common from chronic corrosion which is tolerated as established custom, and from hidden or indirect effects of corrosion. The importance of corrosion damage is not always proportional to the volume of metal affected.

The functional aspects of corrosion are listed. Analysis is made of the ways in which corrosion enters into the cost of doing business. Explanations are given of the direct and indirect ways corrosion may effect capital investment, operating costs, product sales, maintenance costs, overhead costs and market competitive condition of and company.
Topic of the Month—Stress Corrosion Cracking Of a Gold Wedding Ring
Authors: REINHART FRED M.
Published: July 2014

A low karat gold alloy wedding ring that had been buried in a garden was unearthed recently and found to be brittle and cracked in many places. The cracks were identified as having been caused by stress corrosion. This condition probably resulted from the presence of residual internal stresses which were combined either with perspiration of the wearer or with the fertilizer used in the garden, or both.
Current Requirements for Cathodic Protection of Pipe Lines★
Authors: PARKER MARSHALL E.
Published: July 2014

The problem faced by the engineer seeking to cathodically protect a buried pipe line is to find the best and most economical way to drain from certain selected points on the line sufficient current to give adequate protection. Three basic methods to this end are placing the line under full protection, placing the line under partial protection and calculating the requirements for complete protection, both using, temporary installations; and measuring the electrical characteristics of the line and calculating its behavior under various proposed systems.

The fourth method—an empirical estimate—is more important than its nature would indicate because certain assumptions based on observation and experience usually are helpful in arriving at a final conclusion.

Principal problems also faced by the engineer are those of securing electrical continuity where joints other than welded are used and insulating the line from other buried structures.

The author recommends a procedure involving steps such as: Determining static potentials, draining interrupted current from selected points and from data thus collected determining the relationship between polarization and driving voltage and attenuation of driving voltage; computing desired effect of combinations of drainage currents.

Also discussed are such questions as technique for making potential readings, various means of plotting data for best use, what constitutes “adequate” protection, where the electrode should be placed in making potential readings and other matters.
Carbon Anode Installed In Electric Cable Conduit★
Authors: DAVIS HOWARD L.
Published: July 2014

A high ampere-year impressed anode consisting of graphite rods connected to an insulated header wire has been developed and installed by the Philadelphia Electric Company in its underground conduit system. The rods are two inches in diameter and 18 inches long. They are spaced five feet apart and pulled into a duct in lengths up to 500 feet. Special reels with flat sides are used to handle the anode. The first installation was in 6000 feet of conduit to protect lead sheathed power cables. Direct current is supplied to this anode by one rectifier located in the middle of the conduit run. Tests have indicated that protection has been obtained comparable to that available with continuous metal ribbon anodes, but life expectancy is considerably longer and troubles due to anode separation caused by uneven dissipation of ribbon type anodes is avoided.
On the Passivity of Iron★
Authors: BONHOEFFER KARL FRIEDRICH
Published: July 2014

Descriptions are given of the various phenomena associated with the passivation and reactivation of iron in concentrated nitric acid. Covered are apparent and true passivation potential, apparent and true passivation current density, passivity producing and passivity maintaining current density. Information is given also on equivalent current density in a redox system, the role of nitrous acid in passivation by concentrated nitric acid, the corrosion of passive iron, refractoriness toward activation, rhythms and activity waves.
Organization and Activity Of the Corrosion Control Group Of a Large Public Utility★
Authors: McAMIS JAMES W.
Published: July 2014

Methods developed to accumulate information and direct the corrosion control activities of a utility with 2900 miles of piping with 335,000 meters on service take-offs are discussed. Data are collected in the form of maps, recommendations and drawings of installations. Available information on relative corrosivity of certain areas is plotted to a central map. The Corrosion Control Group generally supervises mitigation measures, with actual work under foremen, who also are responsible for training personnel. Testing of the effectiveness of installations has been limited by lack of time and personnel, but more is expected to be done soon. Use of holiday detectors is recommended.
The Pertechnetate Ion as an Inhibitor Of the Corrosion of Iron and Steel★
Authors: CARTLEDGE G. H.
Published: July 2014

Theoretical consideration of possible mechanisms to account for the action of inorganic corrosion inhibitors of the XO4n− type led to the discovery that the pertechnetate ion, TcO4−, inhibits the corrosion of iron and carbon steels in aerated water at temperatures from 23 to 250 C, which was the highest temperature investigated. The chemistry and nuclear properties of technetium are such as to make it very useful in studying the inhibitory process. Thus, it has been shown that inhibition may be achieved without precipitating more than radiochemical traces of reaction products on the metal and even this amount is shown to be most probably of secondary origin. Exposures of two years have not been attended by a continuous increase in the amount of precipitated technetium. It was found that even at 250 C 5 ppm of technetium (5 × 10−5 f KTcO4) in distilled aerated water effectively inhibited the attack on an SAE 1010 steel. The inhibition depends upon the maintenance of some minimum concentration of dissolved pertechnetate, the amount being dependent upon the nature of the metal and its surface activity. The evidence points to a weak, reversible adsorption of the inhibitor ion as the source of inhibition. The perrhenate ion, ReO4−, is very similar to the pertechnetate ion in geometry and charge, yet it was found to have no inhibitory properties under any of several conditions studied. The observations make it clear that inhibition arises from some intra-ionic property and it is tentatively suggested that this is a degree of internal polarity sufficient to induce a short-range electrostatic polarization at the interface, whereby the activation energy for the cathodic part of the corrosion process is increased.
Stress Corrosion Cracking Of Hardenable Stainless Steels
Authors: BLOOM F. K.
Published: July 2014

Hardenable stainless steels, like other high-strength steels, are susceptible to cracking under the combined influence of tensile stress and corrosion, depending on the severity of the stress, the nature of the media and to a large extent, on their hardness. The most severe conditions are acid solutions containing sulfides, which promote entry of hydrogen into the steel and where chlorides are present to promote pitting. In such media cracking may occur in the standard grades under stress at hardnesses of Rockwell C24, in severe marine atmospheres at C40 and in industrial atmospheres at C45. Type 422, a modified 12 percent chromium alloy, tempered at 1200 F to Rockwell C30 and the precipitation-hardening alloys, 17-4 PH and 17-7 PH, overaged to the same hardness level were the most resistant materials tested.

Types 410, 416 and 431 performed as well as or somewhat better than low alloy steels when heat treated to equivalent hardness levels. Tempering them at 1100 F or higher temperatures provided good resistance to cracking in the severest media.

Internal stresses generated during quenching can promote stress corrosion cracking without imposing additional external stresses. Interrupted quenching (martempering) is helpful in minimizing stresses from this source and is recommended as a heat treating practice for valve trim and other parts used fully hardened in service likely to cause corrosion cracking.
An Educational Lecture The Electrochemistry of Inhibitor Action★
Authors: MEARS R. B.
Published: July 2014

Principles involved in the electrochemistry of inhibitor action are discussed. Electrical terms are used to explain the inhibiting action of substances and to show what properties are desirable in an inhibitor. The mechanism by which sodium chromate and sodium hexametaphosphate function as inhibitors is discussed in detail.
Nomograph for Corrosion Rate Calculations—A Technical Note
Authors: BASS HENRY K. , ANDREWS ROBERT V.
Published: July 2014

A nomograph which facilitates the determination of corrosion rate in mils per year is described. A typical problem involving calculation of corrosion rate is worked out on the accompanying nomograph.
The Investigation of an Unusual Cause of Shipbottom Pitting★
Authors: DEVOLUY R. P.
Published: July 2014

Two unusual and severe cases of shipbottom pitting were encountered within the space of a few years. Although the two incidents occurred in polluted harbors 3000 miles apart, the vessels involved showed the same symptoms. These symptoms were rapid pitting, inactivation of the blackened antifouling paint and good electrical conductivity of the black surface film. The black conversion product, found only in the upper layer of the antifouling paint, was shorted to the steel hull.

A study of the painting history of the vessels involved and of the conditions to which they were exposed in service indicated two common factors were present on ships that pitted. First, there was contact between the antifouling paint and the steel hull and secondly, there was exposure to sulfide forming waters. When one of these factors was missing, vessels exposed to the other condition did not show unusual pitting.

To confirm a theory as to the cause of pitting a series of test panels duplicating conditions experienced in service were prepared. The tests, with suitable controls tended to substantiate the theory advanced. From information so obtained it was possible to recommend simple measures that would prevent the recurrence of the severe underwater corrosion described.
Aqueous Corrosion of Aluminum (Part 2-Methods of Protection Above 200 C)
Authors: DRALEY J. E. , RUTHER W. F.
Published: July 2014

At elevated temperatures most aluminum alloys in water suffer severe penetrating attack, resulting in their relatively rapid destruction. This penetrating attack is explained in terms of mechanical damage as a result of diffusion of corrosion-product hydrogen into the metal.

It is prevented by adding to the water cations which are reduced on the aluminum to form deposits of low hydrogen overvoltage metals. It is also prevented in untreated water by using aluminum alloyed with the same metals. Alloying metals observed to be beneficial are nickel, copper, cobalt, iron and platinum, with nickel probably the most effective.

There has been developed an alloy, containing approximately 1 percent nickel in 1100 aluminum,which appears to be completely safe against the penetrating attack up to 350 C. It is easy to make and is workable. It probably can be used, from a corrosion resistant point of view, wherever its normal reaction rate with water or a solution is tolerable. Penetration rates in static distilled water range from approximately 0.5 mg/dm2-day at 150 C to 18 mdd at 350 C (0.3 to 9 mils per year). They are higher where there is significant flow velocity of water past metal. 6.4.2
Casing Corrosion in the Hugoton Gas Field★
Authors: KOGER W. C.
Published: July 2014

A casing leak survey in the Hugoton Gas Field was made to obtain information with which the casing corrosion problem could be evaluated and the most severely affected areas located. It was determined that leak frequency was relatively low but that leaks usually resulted in decreased deliverability or loss of the well. Because the pool is expected to be productive for another 30 years, the seriousness of the problem was not reflected entirely by current leak frequency.

Work to date indicates current application based on indications derived from surface potential measurements is sufficient to protect the wells and that the required current is obtainable from galvanic anodes. This latter fact is important because each well is located in the center of a section.

Interference from rectifier installations has been found in the field, presenting a new problem in efforts to protect casing cathodically from corrosion. 8.4.3
The Structure of Oxide Scales on Chromium Steels
Authors: YEARIAN H. J. , RANDELL E. C. , LONGO T. A.
Published: July 2014

The structure of the oxide scale formed on commercial chromium steels containing 5 to 26 percent Cr when oxidized in air or oxygen at temperatures from 700 C to 1160 C for times up to 100 hours were determined by X-ray diffraction methods, supplemented in some instances by chemical analysis. Two distinct types of scale were observed: A type scale occurs when the rate of metal loss is less than approximately 10 mg/cm2/day, and B type when the attack rate is in the excessive range. For exposures near the critical conditions an initial A type scale transforms to B type during oxidation.

The essential component of A type scale is Cr2O3. This is usually accompanied by aFe2O3 in an amount which increases with the iron content of the alloy (i.e., with rate of attack). At high temperatures or long oxidation times, dilute solid solutions of each of these phases in the other are formed. When the alloy contains a few tenths percent of Mn, the A type scale may also include copious amounts of MnCr2O4, especially for high chrome alloys and for low temperature oxidations in air.

B type scale is more complex than A scale and may be considered as two layers. The outer layer is duplex and is similar in all respects to the Fe3O4 and Fe2O3 layers of the scale on pure iron. The major constituent of the inner layer, corresponding to the FeO layer on pure iron, is a solid solution, FeFe(2–x)CrxO4, of the spinel type. Throughout most of the layer x varies slowly, but near the metal it rises rapidly to x = 2 and near the Fe3O4 layer it falls rapidly to x=0. The mean value of x lies in the range of about 0.5 to 1.5. The greater the chromium content of the alloy, the higher the temperature and the longer the time of oxidation, the larger is the value of x. In cases of very high attack the series of spinels is accompanied by a series of wustites which are modified by chromium additions ranging downward to zero at the Fe3O4 layer. For 10 to 20 hour oxidations at 925 C and at 1000 C the chromium fraction of total metal in the inner layer is about 1.8 times its value in the alloy, whereas the excess is only about one percent in the scale as a whole.

The experimental data are compared and contrasted with existing information and are qualitatively interpreted by use of a tentatively proposed Fe-Cr-O phase diagram and a special theory of alloy oxidation. 3.2.3
Intrinsic Protection of Water Mains
Authors: UNZ M.
Published: July 2014

Inherent protection against corrosion hazards is essential in water supply systems. External corrosion is reduced by the use of cement coatings and separation of heterogeneous line sections. Internal galvanic action, especially in prestressed concrete structures, is eliminated by separation or matching of materials. A complete solution of the problem is attained only by electrically nonconducting pipe. Internal corrosion and blocking of pipes can be prevented by water treatment.

Investigations on an irrigation system confirm that bare or bituminous coated steel components are anodic to cement coated lines. Irrigation outlets during the dry season also usually are anodic to the trunk line. In anodic areas a chemical absorption process takes place in the cement coating, which intrinsically increases its protective value. The presence of an adequate layer of pure cement over the steel surface is essential for this protective effect. 7.2
Corrosion of Type 347 Stainless Steel and 1100 Aluminum In Strong Nitric and Mixed Nitric-Sulfuric Acids★
Authors: DILLON CHARLES P.
Published: July 2014

Rapid corrosion of a Type 347 stainless steel-clad tank was encountered in the storage of a mixed acid of the composition 85 percent nitric acid-13.5 percent sulfuric acid-1.5 percent water. A laboratory investigation of the mechanisms of attack in this and similar acids shows severe vapor-phase corrosion of austenitic stainless steel above 95 percent total acidity. The attack was unaffected by chloride or metal ion contamination. 1100 aluminum has been found in both laboratory tests and in field experience to be an effective and economical substitute in this service. The aluminum alloy is corroded in the liquid phase at total acidities below 95 percent. 4.3.2
What Does Corrosion Really Cost?
Authors: HIRSCHMANN W. B.
Published: July 2014

Determination of the cost of corrosion is not a simple, straightforward job. A part of the problem depends on what is meant by corrosion and what is meant by cost. This paper is a guide for isolating the cost of corrosion. By also taking into account the effects of taxes and the time value of money, a measure is obtained of the cost of corrosion which is credible, and which is meaningful in relation to other costs and the net earnings of an organization. 1.2.2
The Role of Nickel and Nickel Substitutes In Jewelry Making
Authors: MAIRS K. H. , WILLIAMS J. M.
Published: July 2014

Numerous laboratory tests are reported of couples between 24 and 10 karat gold, sterling silver, 800 silver, 430 stainless iron, composition, 10 percent nickel silver, 18 percent nickel silver, aluminum bronze, LC nickel and 305 stainless steel in both acid and alkaline synthetic perspiration. Expected potential difference occurred between the materials and gold. Type 305 stainless steel showed the least tendency to corrode with the copper base alloys showing the greatest tendency toward corrosion. Potentials in acid perspiration were greater than those in alkaline.

The authors conclude alloys which develop protective films are more satisfactory than those which do not. Resistance of nickel is not entirely satisfactory but no single substitute has the general usefulness of nickel. Under many conditions Type 430 stainless iron is not sufficiently resistant to be useful in jewelry making.
Methods of Preventing Corrosion in Sewerage Systems★
Authors: SPINDEL ERVIN
Published: July 2014

Means of preventing deterioration of structures handling sewage or exposed to the fumes from sewage are discussed. Relative merits and application techniques of chemical additives are considered. Recommendations concerning control through design to increase velocity or eliminate vapor space are weighed. Application of and results achieved through ventilation of sewers are reported in some detail, including service results on installations over periods up to 16 years.

Control through use of materials resistant to the corrosives in sewage is outlined. Special cements, clay and plastic liners, special jointing materials and protective coatings for metallic and non-metallic materials at treatment plants are mentioned. Cathodic protection as an effective control measure is considered and recommended where feasible.
Testing Wrappings on Cathodically Protected Submerged Pipe and Fittings★
Authors: CLAYTON H. M.
Published: July 2014

All 20-mil tapes failed when tested by the Light, Gas & Water Div. of Memphis, Tenn. in 2000 ohms/cm3 water wrapped over 1-inch pipe carrying impressed voltages of —.85 to —2.5. Ten-mil tapes performed better. The principal reasons for failure were poor adhesives and tape elasticity and memory which tended to pull away wrappings over elbows and caps. Coal tar enamel tested under the same conditions performed well.

Test equipment included a device for measuring the conductivity of the water and a transparent plastic box in which the tested samples were submerged. Close check was kept on applied potentials. A record, was kept of water absorbed by the wrappings. It, is believed increased current flow was caused by water creeping under tapes rather than absorption.

Tests were run for periods of eight weeks, gradually increased voltages having the effect of accelerating the tests. Data are graphed for typical tests and a table of data on a typical sample is given. 5.4.5
The Relation of Thin Films to Corrosion★
Authors: RHODIN THOR N.
Published: July 2014

Recent studies of thin oxide films isolated from stainless steels and other ferrous alloys have provided new information on surface properties. Correlations between the unique compositional and structural properties of thin films and alloy corrosion behavior in various corrosive environments have been established.

Evaluation of the resistance to pitting corrosion of silicon-modified Type 316L stainless steel is described as a typical example of an application of a film study to corrosion research. In this case, improved corrosion behavior was correlated with a mutual film-enrichment of silicon and molybdenum and a film-depletion of iron. Experimental alloys of improved purity were prepared and evaluated. Effects of alloy purity, carbon content, and alloying additions were found to influence strongly surface behavior and corrosion resistance.

The mechanism of resistance to pitting corrosion and the protective nature of the associated oxide films are interpreted in terms of the chemistry of hydrated heteropoly acids containing oxides of silicon and molybdenum. 3.8.4
Effect of Hot Hydrogen Sulfide Environments on Various Metals★,—A Contribution to the Work of NACE Task Group T-5B-2 on Sulfide Corrosion at High Temperatures and Pressures in the Petroleum Industry from Sinclair Research Laboratories, Inc., Harvey, III.*
Authors: BRUNS FRANK J.
Published: July 2014

Sinclair platinum catalyst reformers and desulfurizers designed on corrosion rate data taken from literature and laboratory tests had low corrosion rates. However, scaling as a result of high temperature sulfide attack caused clogging and pressure drop.

Plant and bench scale corrosion tests were made using specimens of various steels and alloys directly in catalyst beds. These tests showed that at hydrogen sulfide concentrations considered low only 18-8 stainless steel exhibited sufficient resistance for long time service. Test apparatus is described, procedure outlined and corrosion rates reported on tests made.

Examples of scale formation are shown, constituents analyzed and explanation of scale phenomena offered.

Tests resulted in decisions concerning additional equipment and pointed to certain alloys as desirable for service expected. Refinery corrosion tests of alloy steels and aluminum coated carbon steels were made and corrosion rates plotted, indicating that low chromium steels are satisfactory provided the hydrogen sulfide-hydrogen ratio is lower than 100 ppm. Aluminum coated steels proved to have marked resistance to attack with best results achieved with calorized coatings.

Conclusions on proper material selection related to hydrogen sulfide concentration are given. 3.2.2
Corrosion and Metal Transport In Fused Sodium Hydroxide (Part 2 – Corrosion of Nickel-Molybdenum-Iron Alloys)
Authors: SMITH G. PEDRO , HOFFMAN EUGENE E.
Published: July 2014

Studies were made of the corrosion by fused sodium hydroxide of nickel-rich alloys whose constituents were nickel, molybdenum, and iron exposed at 815 C for 100 hours. The reaction mechanism was found to involve the selective removal of iron and molybdenum from solid solution with nickel and a resultant formation of subsurface porosity. In most cases this porosity was shown to occur in the form of elongated pits which frequently followed tortuous paths and intersected to form a maze of subsurface channels.

Alloys of nickel, molybdenum, and iron containing at least 70 percent nickel showed more resistance to corrosion by sodium hydroxide melts at 815 C than any other alloys which have been tested. 4.7
A Laboratory Study of N-Oleoyl Sarcosine As a Rust Inhibitor in Some Petroleum Products★
Authors: PINES ROBERT M. , SPIVACK JOHN D.
Published: July 2014

Laboratory studies indicate that N-oleoyl sarcosine (I) is an effective oil soluble rust inhibitor in solution in gasoline, mineral oil and silicone lubricants.

Rusting tests used included: Turbine Oil Rusting Test (ASTM D665-54), a Static Immersion Test, Humidity Cabinet Test (JAN H-792), Static Water Drop Test (MIL-L-17353 Bu. Ord.). In addition, a number of auxiliary tests were run to indicate the effect of (I) on other properties of the test liquid.

Hydrocarbon solutions of N-oleoyl sarcosine are particularly effective in preventing rusting in the presence of synthetic sea water and in resisting water extraction of the inhibitor. 5.8.2
An Evaluation of Inhibitors for Corrosion Prevention In An Engine Cooling System★
Authors: ROWE LEONARD C.
Published: July 2014

The variation of coolants used in a multi-metal engine cooling system offers a challenge for corrosion inhibition. The diverse characteristics of this system are discussed along with their relationship to the selection of laboratory test methods to investigate inhibition.

A rotating specimen type of test is used for the evaluation. The effectiveness of inhibitors, such as sodium borate, sodium nitrite, sodium benzoate, potassium dichromate, soluble oil, and sodium mercap-tobenzothiazole, is compared by means of this test. Various test media are used, including ethylenegly-col-water mixtures and tap water with and without additional corrosive constituents. The metals investigated are steel, copper, brass, aluminum, cast iron and solder. The results are based on corrosion rate, microscopic examination, pit depth when applicable, and other general examinations.

This work includes the results of one year static room temperature tests on thirteen galvanic couple combinations for each inhibitor.

Based on the results obtained by conventional corrosion tests, a final examination of a combination of inhibitors is made in a laboratory model which simulates an engine cooling system. This test indicates effective inhibition by this combination in a system using either a copper-brass or aluminum radiator. 4.6.4
Current Requirement for Cathodic Protection Of Oil Well Casing★
Authors: HAYCOCK E. W.
Published: July 2014

Methods at present used to indicate the minimum applied current required to give complete cathodic protection are discussed and evaluated in terms of their scientific basis and their applicability to the protection of oil well casing. Laboratory experiments are described involving the application of cathodic protection currents to a series assembly of galvanic cells. The results of these experiments lead to a modification of the log current—potential criterion of complete protection widely used at the present time. The experiments also indicate the amount of corrosion repressed as a function of the applied protection current, information which is of considerable value when an economic balance is involved. 5.2.4
An Impressed Current Cathodic Protection System Applied to a Submarine
Authors: NELSON E. E.
Published: July 2014

A cathodic protection system using platinum-clad copper anodes on neoprene shields was installed on a fleet-type submarine. Current was supplied from a rectifier to 11 anodes distributed over the hull, the potential being monitored by 13 silver-silver chloride electrodes at selected locations. The system was operated for a ten-month period of active duty after which inspection on a marine railway showed the hull to be in excellent condition with the vinyl paint functioning well. Three of the anodes were damaged but all the cable seals, insulators and anode shields were found intact. The use of platinum-clad anodes of the type employed seems economically feasible since the cost of these anodes constitutes a small part of the cost of installation. Laboratory tests indicate the desirability of replacing the copper anode core by a silver core as an insurance against anode failure in the event of a perforation of the platinum cladding. 5.2.3
The Effect of Dissolved Oxygen on Corrosion of Steel And on Current Required for Cathodic Protection★
Authors: SCHASCHL E. , MARSH G. A.
Published: July 2014

The interrelationship of corrosion rate of steel, dissolved oxygen concentration, agitation, electrode potential, and cathodic protection current density were studied under controlled laboratory conditions. While the corrosion rate of steel is essentially linear with amount of dissolved oxygen, the rate appears to fall almost to zero near 1.0 ppm dissolved oxygen rather than at zero ppm dissolved oxygen as commonly assumed. In the region below 2 ppm dissolved oxygen, there is almost no effect of agitation on corrosion rate; above 2 ppm there is a large effect. By measuring the corrosion rate of an unprotected specimen, it should be possible to compute the minimum current density needed for cathodic protection in the field.

In acidic environments, less current is needed for protection than is predicted by analysis of the mechanism of cathodic protection. This fact suggests that the anodic reaction in low pH corrosion proceeds by the removal of “chunks” of metal which contain several atoms. The “chunk effect” also appears to operate in the neutral range, but only when the corrosion rate is very high.

The effect of differential aeration on corrosion rates is discussed in detail. 5.2.4
Sprayed Metal as a Base for Paints★
Authors: INGHAM H. S.
Published: July 2014

The use on steel of thin metallized coatings of zinc and aluminum is discussed in detail. A number of recommendations are made regarding surface preparation. Consideration is given to the effects sprayed metal coatings have on the application, appearance and performance of the paints applied over them. The cause and remedies for paint failures are discussed with particular attention paid to underground power plant applications. The selection of paints and primers for a given sprayed metal and the use of thinners are discussed briefly. 5.3.2