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Sample records for corrosion bajo tension

  1. Microbiological corrosion in low carbon steels; Corrosion microbiologica en aceros de bajo carbono

    Energy Technology Data Exchange (ETDEWEB)

    Medina-Custodio, O; Ortiz-Prado, A; Jacobo-Armendariz, V. H; Schouwenaars-Franssens, R [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)]. E-mail: medina_1979@yahoo.com; armandoo@servidor.unam.mx; vjacobo@dgapa.unam.mx; raf_schouweenaars@yahoo.com

    2009-01-15

    The Microbiologically Induced Corrosion affects several industries, such as oil industry where it is estimated that 20% to 30% pipes failures are related with microorganism. The chemical reactions generate ions transfer, this validate the use of electrochemical technique for its analysis. Coupons submerged in a nutritional medium with presence and absence of three different microorganisms during two periods, 48 hours and 28 days were studied. Polarization resistance (Rp) and Electrochemical Impedance Spectroscopy (EIS) techniques were applied to determine the corrosively of the systems. The results show a greater corrosive effect of abiotic systems, this indicates a microorganisms protection effect to the metal, opposite to the first hypothesis. This result was ratified observing surface coupons by using Scanning Electron Microscopy (SEM) technique. A possible mechanism based on Evans - Tafel graph is proposed to explain inhibitor microorganism effect. [Spanish] La corrosion microbiologica es un tipo comun de deterioro que afecta diversas industrias, una de ellas es la petrolera en la que se estiman que el 20% o 30% de fallas en las tuberias de trasporte de hidrocarburos es favorecida por microorganismos. Las reacciones quimicas que sustentan estos, generan transferencia de iones, lo que justifica el empleo de tecnicas electroquimicas para su analisis. En este trabajo, se estudiaron probetas de acero de bajo carbono SAE 1018, sumergidas en un medio nutritivo rico en cloruros en presencia y ausencia de tres diferentes cargas microbianas, en tiempos de exposicion de 48 horas y 28 dias. Se realizaron ensayos de resistencia a la polarizacion (Rp) y espectroscopia de impedancia electroquimica (EIS) para determinar el efecto corrosivo de los diferentes sistemas. Los resultados muestran que el medio abiotico causa el mayor efecto corrosivo, lo que indica un efecto protector de los microorganismos al metal contradiciendo la hipotesis inicialmente propuesta. La observacion

  2. Flexural behavior of bonded post-tensioned concrete beams under strand corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuhui [College of Civil Engineering and Mechanics, Xiangtan University, 411105 Xiangtan (China); School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Wang, Lei, E-mail: leiwlei@hotmail.com [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Zhang, Jianren; Ma, Yafei [School of Civil Engineering and Architecture, Changsha University of Science & Technology, 410114 Changsha (China); Industry Key Laboratory of Traffic Infrastructure Security Risk Management (CSUST), 410114 Changsha (China); Liu, Yongming [School for Engineering of Matter, Transport and Energy, Arizona State University, 85281 Tempe, AZ (United States)

    2017-03-15

    Highlights: • Flexural behavior of bonded PT beams with strand corrosion is experimental tested. • Cracking, stiffness, ultimate strength, failure & ductility of beams are clarified. • A coefficient is proposed to measure incompatible strain between strand & concrete. - Abstract: An experimental test is performed to investigate the flexural behavior of bonded post-tensioned concrete beams under strand corrosion. Eight beams are designed and subjected to accelerated method to different corrosion levels. The initial stiffness of beams is observed by cyclic loading-unloading test during the corrosion procedure. Corrosion effects on concrete cracking, post-cracking stiffness, ultimate strength, failure mode and ductility are then clarified by the flexural test. And, a coefficient is introduced to quantify the incompatible strain between corroded strand and concrete. Results show that the prestress force loss of strand has almost the linear relation with corrosion loss. Strand corrosion affects slightly the initial stiffness of beam before flexural cracking, but degrades significantly the post-cracking stiffness of beam as the corrosion loss exceeds 27.0%. Slight corrosion of strand has little effects on beams flexural behavior. The severe corrosion, however, decreases the number of crack, changes the failure mode form the concrete crushing to strand rupture, degrades the ductility and the ultimate strength of beams, and leads to the incompatible strain between strand and concrete. In the present test, the incompatible strain decreases about 20% of the flexural strength as the corrosion loss exceeds 27.0%.

  3. Accelerated corrosion testing, evaluation and durability design of bonded post-tensioned concrete tendons

    Science.gov (United States)

    Salas Pereira, Ruben Mario

    2003-06-01

    In the last few years, the effectiveness of cement grout in galvanized or polyethylene ducts, the most widely used corrosion protection system for multistrand bonded post-tensioned concrete tendons, has been under debate, due to significant tendon corrosion damage, several reported failures of individual tendons as well as a few collapses of non-typical structures. While experience in the USA has been generally good, some foreign experience has been less than satisfactory. This dissertation is part of a comprehensive research program started in 1993, which has the objectives to examine the use of post-tensioning in bridge substructures, identify durability concerns and existing technology, develop and carry out an experimental testing program, and conclude with durability design guidelines. Three experimental programs were developed: A long term macrocell corrosion test series, to investigate corrosion protection for internal tendons in precast segmental construction; a long term beam corrosion test series, to examine the effects of post-tensioning on corrosion protection as affected by crack width; and, a long term column corrosion test series, to examine corrosion protection in vertical elements. Preliminary design guidelines were developed previously in the overall study by the initial researchers, after an extensive literature review. This dissertation scope includes continuation of exposure testing of the macrocell, beam and column specimens, performing comprehensive autopsies of selected specimens and updating the durability design guidelines based on the exposure testing and autopsy results. After autopsies were performed, overall findings indicate negative durability effects due to the use of mixed reinforcement, small concrete covers, galvanized steel ducts, and industry standard or heat-shrink galvanized duct splices. The width of cracks was shown to have a direct negative effect on specimen performance. Grout voids were found to be detrimental to the

  4. DEVELOPMENT OF SOFTWARE SYSTEM FOR MONITORING OF STRESS CORROSION CRACKING OF THE PIPELINE UNDER TENSION

    Directory of Open Access Journals (Sweden)

    Z. K. Abaev

    2016-01-01

    Full Text Available The software and hardware development tendency, providing the automated monitoring and control of basic and auxiliary technological processes of gas transportation via system of main gas pipelines has been revealed. The article discusses the stages of creation of the software of system of monitoring corrosion cracking under tension (SCC. The new useful adequate regression models development determining the risk level of LCC is shown. A ranking sections algorithm of main gas pipeline (MG on the propensity to SCC is presented. Adequate developed regression equation determining the LCC risk level has been developed. To count the main gas pipeline lifetime the variable rank of the danger of SCC (RSCC on the basis of methods of fuzzy logic is proposed to use. Implementation of the fuzzy model was carried out using the graphical tools developed in MATLAB using the expansion pack Fuzzy Logic Toolbox. The working algorithm of developed program and the screen forms are presented.

  5. Cracks propagation by stress corrosion cracking in conditions of Boiling Water Reactor (BWR); Propagacion de grietas por corrosion bajo esfuerzo en condiciones de reactor de agua hirviente (BWR)

    Energy Technology Data Exchange (ETDEWEB)

    Fuentes C, P

    2003-07-01

    This work presents the results of the assays carried out in the Laboratory of Hot Cells of the National Institute of Nuclear Research (ININ) to a type test tube Compact Tension (CT), built in steel austenitic stainless type 304L, simulating those conditions those that it operates a Boiling Water Reactor (BWR), at temperature 288 C and pressure of 8 MPa, to determine the speed to which the cracks spread in this material that is of the one that different components of a reactor are made, among those that it highlights the reactor core vessel. The application of the Hydrogen Chemistry of the Water is presented (HWC) that is one alternative to diminish the corrosion effect low stress in the component, this is gets controlling the quantity of oxygen and of hydrogen as well as the conductivity of the water. The rehearsal is made following the principles of the Mechanics of Elastic Lineal Fracture (LEFM) that considers a crack of defined size with little plastic deformation in the tip of this; the measurement of crack advance is continued with the technique of potential drop of direct current of alternating signal, this is contained inside the standard Astm E-647 (Method of Test Standard for the Measurement of Speed of Growth of Crack by fatigue) that is the one that indicates us as carrying out this test. The specifications that should complete the test tubes that are rehearsed as for their dimensions, it forms, finish and determination of mechanical properties (tenacity to the fracture mainly) they are contained inside the norm Astm E-399, the one which it is also based on the principles of the fracture mechanics. The obtained results were part of a database to be compared with those of other rehearsals under different conditions, Normal Chemistry of the Water (NWC) and it dilutes with high content of O{sub 2}; to determine the conditions that slow more the phenomena of stress corrosion cracking, as well as the effectiveness of the used chemistry and of the method of

  6. Applied methods for mitigation of damage by stress corrosion in BWR type reactors; Metodos aplicados para la mitigacion del dano por corrosion bajo esfuerzo en reactores BWR

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez C, R.; Diaz S, A.; Gachuz M, M.; Arganis J, C. [Instituto Nacional de Investigaciones Nucleares, Gerencia de Ciencia de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1998-07-01

    The Boiling Water nuclear Reactors (BWR) have presented stress corrosion problems, mainly in components and pipes of the primary system, provoking negative impacts in the performance of energy generator plants, as well as the increasing in the radiation exposure to personnel involucred. This problem has caused development of research programs, which are guided to find solution alternatives for the phenomena control. Among results of greater relevance the control for the reactor water chemistry stands out particularly in the impurities concentration and oxidation of radiolysis products; as well as the supervision in the materials selection and the stresses levels reduction. The present work presents the methods which can be applied to diminish the problems of stress corrosion in BWR reactors. (Author)

  7. Propagation of cracks by stress corrosion in conditions of BWR type reactor; Propagacion de grietas por corrosion bajo esfuerzo en condiciones de reactor de agua en ebullicion (BWR)

    Energy Technology Data Exchange (ETDEWEB)

    Merino C, F.J. [ININ, 52045 Estado de Mexico (Mexico); Fuentes C, P. [ITT, Metepec, Estado de Mexico (Mexico)]. E-mail: fjmc@nuclear.inin.mx

    2004-07-01

    In this work, the obtained results when applying the Hydrogen Chemistry to a test tube type Compact Tension (CT), built in austenitic stainless steel 304l, simulating the conditions to those that it operates a Boiling Water Reactor (BWR), temperature 288 C and pressure of 8 MPa are presented. With the application of this water chemistry, seeks to be proven the diminution of the crack propagation speed. (Author)

  8. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

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

  9. Corrosion

    Science.gov (United States)

    Slabaugh, W. H.

    1974-01-01

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

  10. Clivajes, tensiones y dinámicas del cooperativismo de trabajo bajo programas sociales: el boom de las cooperativas del Programa Ingreso Social con Trabajo - Argentina Trabaja

    OpenAIRE

    2015-01-01

    Se analizan tensiones, clivajes, supuestos y actores desde el propio diseño del programa, usando como fuentes tanto entrevistas a informantes calificados y a miembros de organizaciones sociales, como documentos públicos e información proveniente de espacios de discusiones sobre la temática. Fil: Arcidiácono, Pilar. Universidad de Buenos Aires. Facultad de Ciencias Sociales. Buenos Aires. Argentina Fil: Bermúdez, Ángeles. Universidad de Buenos Aires. Facultad de Ciencias Sociales. Buenos...

  11. Alternativa analítica a la determinación de tensiones bajo zapatas rectangulares con flexión biaxil y despegue parcial

    Directory of Open Access Journals (Sweden)

    Irles Más, Francisco

    1992-06-01

    Full Text Available The calculation of stresses under rectangular footings with biaxial bending is carried out by solving the 3-equations system that sets up the load and soil stresses equilibrium. When a planar soil stresses distribution is assumed, and the area is in full compression, the above system is linear and its solution immediate. With increasing eccentricities, some corners of the footing can get detached from the soil, the system becoming nonlinear, and difficulties arise in its resolution. Classic answers to this problem have been found through the numerical (iterative solution of the system, or by getting nondimensional graphs for direct calculation, whose sketches also require a numerical solution. In the paper an analytical alternative is presented which will lead to obtaining explicit solutions for these stresses and neutral axis location.

    Como alternativa a las técnicas numéricas para la obtención de la distribución de presiones bajo una zapata rectangular con flexocompresión biaxil y presencia de despegues, supuesta lineal, en este artículo se han obtenido fórmulas explícitas, excepto para el caso de despegue en un solo vértice, en el cual el problema se reduce al inmediato de resolver una ecuación polinómica de grado 8 y una sola variable, con garantía y unicidad de solución en el intervalo de definición del problema; caso que, a su vez, presenta situaciones particulares explicitables.

  12. Análisis de tensiones en árboles de geometría compleja bajo cargas debido al efecto giroscópico.

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    M. Sánchez Noa

    2005-09-01

    Full Text Available En el presente trabajo se exponen los resultados del análisis realizado en árboles de compleja geometríapertenecientes a un multiplicador planetario tipo 2KH-A destinado a emplearse en aerogeneradores deelectricidad. En el mismo, se presentan los modelos físico-matemáticos de dichos árboles para seranalizados mediante el método de los elementos finitos, considerando el estado de carga que surge alfuncionar el mecanismo y contemplando el efecto adicional de las cargas giroscópicas. Se muestran laszonas de conflicto de tensiones y se analizan propuestas de diseño que permitan, garantizando laresistencia y rigidez, realizar variaciones dimensionales y mejorar la compacidad de los elementos,disminuyendo a la vez el peso de los mismos.

  13. Determinación de los indicadores de deformación bajo tensiones multiaxiales de embutición. Aplicación al acero electrocincado DC-05 (UNE en ISO 10130

    Directory of Open Access Journals (Sweden)

    Miguel, V.

    2007-04-01

    Full Text Available In this work a methodology to investigate deep drawing quality steel sheets deformation tendency under multiaxial deep drawing stresses has been proposed. The method consists in assaying a sheet in a wedge die in order to introduce a pure shear estate in the material. 0º, 45º and 90º rolling directions are selected in the assays, and transversal strain is the variable considered in them. A strain coefficient ‰ has been defined in order to evaluate thickness variations in the test. Almost no changes in thickness have been registered and this indicates that strain carried out in the test is similar to that taking place in deep drawing. The stress necessary for practice a certain plastic deformation is obtained too and a potential function between them is formulated. Indicators presented in this work are compared to anisotropy and strength coefficients obtained in normalized tensile tests. These results allow us to justify the steel behaviour in the cup deep drawing processes related to ear forming.

    En este trabajo se establece una metodología para la investigación de la tendencia a la deformación de chapa de acero de alta embutibilidad bajo tensiones multiaxiales de embutición. El método consiste en ensayar chapa en una matriz con forma de cuña produciendo en el material un estado de deformación típico de embutición (pure shear. Se seleccionan tres direcciones de laminación (0º, 45º y 90º y se establece la deformación en anchura como variable de ensayo. Se ha definido un coeficiente de deformación con el fin de evaluar las variaciones obtenidas en el espesor del material constatándose la no existencia de cambios significativos en éste. También, se obtiene la tensión necesaria para realizar distintas deformaciones estableciendo correlaciones de tipo potencial tensión-deformación. Se contrastan los indicadores obtenidos con el índice de anisotropía y el de endurecimiento del material bajo condiciones normalizadas

  14. Atmospheric corrosion of low carbon steel in a polar marine environment. Study of the effect of wind regime; Corrosion atmosferica del acero bajo en carbono en un ambiente marino polar. Estudio del efecto del regimen de vientos

    Energy Technology Data Exchange (ETDEWEB)

    Rivero, S.; Chico, B.; Fuente, D. de la; Morcillo, M.

    2007-07-01

    The present work studies the atmospheric corrosion of carbon steel (UNE-EN 10130) in a sub-polar marine environment (Artigas Antarctic Scientific Base (BCAA), Uruguay) as a function of site atmospheric salinity and exposure time. A linear relationship is established between corrosion rate and airborne salinity deposition rate, valid in the deposition range encountered (125-225 mg Cl-l/m{sup 2}.d) and a bi logarithmic relationship established between corrosion and exposure time (1-4 years). Atmospheric salinity is related with the monthly wind speed average, based on the concept of the wind run. chloride ion deposition rates of less than 300 mg Cl-l/m{sup 2}.d are related with remote (oceanic) winds and coastal winds basically of speeds between 1-40 km/h, while higher deposition rates (300-700 mg Cl-/m{sup 2}.d) correspond to coastal marine winds of a certain persistence with speeds of between 41-80 km/h. (Author) 39 refs.

  15. Caracterización mediante la técnica EBSD de la deformación de chapa de acero inoxidable AISI 304 DDQ bajo tensiones multiaxiales típicas de la embutición

    Directory of Open Access Journals (Sweden)

    Coello, J.

    2009-10-01

    Full Text Available The main aim of this work is to evaluate AISI 304 DDQ stainless steel behaviour under deep drawing deformation condition, that is, pure shear deformation in which material suffers a typical deformation under tension-biaxial compression stresses system. The microestructural evolution has been investigated by optical microscopy and by EBSD technique. The success of the EBSD analysis has been established for the deformation conditions experimented here. It has been determined the rolling direction and the equivalent strain influence on the crystallographic orientation maps, misorientation diagrams and poles figures. The results let the authors say the low angle misorientations corresponding to 0, 45 and 90° rolling directions have an inverse correlation with the material anisotropy. Initial prestraining has been considered also and the analysis of this aspects lead to establish that the increment of the intragranular misorientations with the strain depends on the initial state of the steel; this increment is observed to be minor for samples with initial prestraining. High angle misorientation analysis (>15° indicates that the grain boundaries character distributions depends on the deformation.

    El objetivo de este trabajo es evaluar el comportamiento del acero inoxidable AISI 304 DDQ durante un proceso de deformación típico del conformado de chapa por embutición, tracción-compresión biaxial (T-CC, determinando la evolución microestructural mediante microscopía óptica y EBSD. Se ha establecido la validez del análisis efectuado por EBSD para las condiciones de deformación consideradas en este trabajo. Se ha analizado la influencia de la dirección de laminación y de la deformación equivalente sobre los mapas de orientación cristalina, diagramas de desorientación y figuras de polos inversa, determinando que las desorientaciones de ángulo bajo obtenidas en muestras deformadas a 0°, 45°, y 90° respecto a la dirección de

  16. Revalorización del ambiente y los espacios locales. Transformaciones del poder y la autoridad locales en Latinoamérica bajo las tensiones de los procesos de globalización

    OpenAIRE

    Vargas Hernández, José Guadalupe

    2006-01-01

    Este trabajo se propone como objetivo analizar las implicaciones en las transformaciones del poder y la autoridad locales a partir de las tensiones del poder en los procesos de globalización económica, las transformaciones del poder en Latinoamérica y la tendencia de revalorización del ambiente y los espacios locales. Se determina en lo importante que las autoridades actúen a través del espacio público de las estructuras político institucionales del gobierno local democrático, de tal forma qu...

  17. Influencia de la sobremaduración en las propiedades mecánicas y comportamiento a corrosión bajo tensión de una aleación de aluminio 7075 T6

    Directory of Open Access Journals (Sweden)

    Badía, J. M.

    2004-04-01

    Full Text Available The effect of a reageing heat treatment following a T6 temper on the mechanical properties and the stress corrosion cracking behaviour (SCC on the EN AW 7075 aluminium alloy is studied. The reageing time was 27 hours for all the temperatures used: 147, 152 and 163 ºC; this last temperature is indicated in the MIL-H-6088F standard to obtain the T73 temper from the T6 temper. The mechanical properties and the stress corrosion behaviour are evaluated and, compared with the T6 and T73 tempers. The evolution of the microstructure is analysed with transmission electron microscopy (TEM and differential scanning calorimetry (DSC techniques, and related with the properties. The reageing following to the T6 temper made a more stable structure higher the temperature, and, consequently, lowing the stress corrosion susceptibility. For temperatures lower than 147 ºC, this diminution of stress corrosion susceptibility occurs without reducing the mechanical properties. So, the 147 ºC reageing heat treatment has better stress corrosion behaviour than the T6 temper, with similar mechanical properties. By the other hand, the stress corrosion susceptibility achieved with the 152 ºC reageing is slightly worse than the T73 one, but their mechanical properties are better.

    En este trabajo se estudia el efecto de la aplicación de una etapa de remaduración posterior al estado T6 sobre las propiedades mecánicas y el comportamiento a corrosión bajo tensiones de una aleación EN AW 7075. Todas las remaduraciones se dieron durante 27 horas a tres temperaturas distintas: 147, 152 y 163 ºC; esta última corresponde a la indicada por la norma MIL-H-6088F para la obtención del estado T73 a partir del estado T6. Se evalúan las propiedades mecánicas y a corrosión bajo tensiones de estos tratamientos, teniendo como referencia los tratamientos T6 y T73. Se analiza la evolución de la microestructura con técnicas de microscopia electrónica de transmisión (TEM y

  18. Spring back evaluation by bending under tension tests in conditions of multiaxial stresses corresponding to deep drawing processes. Application to AISI 304 DDQ stainless steel sheet; Evaluacion del springback mediante ensayos de doblado bajo tension en condiciones de multiaxialidad tipicas de los procesos de embuticion profunda. Aplicacion a chapa de acero inoxidable AISI 304 DDQ

    Energy Technology Data Exchange (ETDEWEB)

    Miguel, V.; Coello, J.; Martinez, A.; Calatayud, A.

    2013-09-01

    In this paper, a methodology has been developed for evaluating the spring back of AISI 304 DDQ stainless steel sheet based on a bending under tension test. The main difference of the methodology herein carried out is that tests are made under the multiaxial stresses state that take place in deep drawing processes. This affects to the level of stress value in the test and to the hardening state of the sheet. Springback evaluation has been done in two different areas. Bending area has been evaluated from elastic recovery ratio defined as the ratio between the bending radius after and before bending. Bending and unbending extreme has been studied from the measured curvature radius in this area and taking into account the geometric equivalence of the test with the drawing cups process. Results found allow to state that drawing ratio or deformation ratio have a negligible influence on the springback into the range of values experimented here. Bending radius has hardly influence as well while bending angle is the most significant variable. The results obtained are compared to those measured in deep-drawn cups, finding a great agreement. (Author)

  19. Túnel bajo el agua

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    Stamhuis, E.

    1964-03-01

    Full Text Available This article describes the results obtained by the Dutch Central Institute of Scientific Research when studying the problem of underwater tunnels. This Institute has sought to establish general specifications for the design of this type of tunnels, so that they shall be more efficient than those at present in use. Firstly, a study was made of the strength, waterproof qualities, and most rational type of ventilation, with a view to drawing up of general principles on this aspect of the design. An analysis is given of the shape, suitable cross sections and constructive methods, and these are compared with those adopted in the construction of underwater tunnels at present in use in America. Particular attention has been given to designs which are largely based on prefabrication and the use of factory made structural parts, and also on the transport and erection of these at the site. The author goes on to discuss the interplay of soil and water pressures, buoyancy forces, and cases in which the tunnel is subjected to important bending and shear forces on particular sections of it. In this connection care is taken to give the theoretical considerations a ready practical interpretation. In particular, a description is given of special distance pieces which connect the two tubes making up a tunnel, also the system of joining two sections of the tube, and the measure of watertightness and flexibility which such joints provide. Finally, a summary is given of the theoretical foundations, as well as a number of observations and items of advise, which are applicable to these types of structures.El ingeniero A. Eggink describió, en un trabajo publicado últimamente, un nuevo tipo de túnel bajo el agua para canalizar la circulación rodada. En este trabajo se desarrolla un análisis sobre las consideraciones que han jugado un papel predominante en la redacción del proyecto de ejecución de un túnel subacuo. Acompañan al trabajo los resultados referentes

  20. Analyses of containment structures with corrosion damage

    Energy Technology Data Exchange (ETDEWEB)

    Cherry, J.L.

    1996-12-31

    Corrosion damage to a nuclear power plant containment structure can degrade the pressure capacity of the vessel. For the low-carbon, low- strength steels used in containments, the effect of corrosion on material properties is discussed. Strain-to-failure tests, in uniaxial tension, have been performed on corroded material samples. Results were used to select strain-based failure criteria for corroded steel. Using the ABAQUS finite element analysis code, the capacity of a typical PWR Ice Condenser containment with corrosion damage has been studied. Multiple analyses were performed with the locations of the corrosion the containment, and the amount of corrosion varied in each analysis.

  1. Stress corrosion (Astm G30-90 standard) in 08x18H10T stainless steel of nuclear fuel storage pool in WWER reactors; Corrosion bajo esfuerzo (Norma ASTM G30-90) en acero inoxidable 08x18H10T de piscinas de almacenamiento de combustible nuclear en reactores V.V.E.R

    Energy Technology Data Exchange (ETDEWEB)

    Herrera, V.; Zamora R, L. [Centro de Estudios Aplicados al Desarrollo Nuclear (Cuba)

    1997-07-01

    At the water storage of the irradiated nuclear fuel has been an important factor in its management. The actual pools have its walls covered with inoxidable steel and heat exchangers to dissipate the residual heat from fuel. It is essential to control the water purity to eliminate those conditions which aid to the corrosion process in fuel and at related components. The steel used in this research was obtained from an austenitic inoxidizable steel standardized with titanium 08x18H10T (Type 321) similar to one of the two steel coatings used to cover walls and the pools floor. the test consisted in the specimen deformation through an U ply according to the Astm G30-90 standard. The exposition of the deformed specimen it was realized in simulated conditions to the chemical regime used in pools. (Author)

  2. La Ciudad bajo el neoliberalismo

    OpenAIRE

    Jaime Ornelas Delgado

    2000-01-01

    En este artículo se exponen algunas reflexiones referidas a los diversos impactos que el neoliberalismo ha tenido en las áreas urbanas en México. En una primera parte se analizan los aspectos esenciales del modelo económico neoliberal; en la segunda se exponen los efectos de este modelo en las ciudades, tanto los que ya están presentes como los que se prevé que puedan aparecer. Asimismo, se estudia cómo se ha organizado y ocupado el territorio en las ciudades bajo el modelo neoliberal y cuále...

  3. Viviendas de muy bajo coste

    Directory of Open Access Journals (Sweden)

    Lemus, V.

    1982-11-01

    Full Text Available Not available.En el Instituto de Investigaciones en Materiales de la Universidad Nacional Autónoma de México, se está desarrollando un área de investigación sobre tecnología de materiales y tecnología de sistemas constructivos, la cual está integrada por diversos proyectos encaminados a solucionar problemas relativos a la vivienda. El presente trabajo consiste en el desarrollo de materiales compuestos a base de desechos agrícolas e industriales, con características tales como baja densidad, resistencia adecuada, excelentes propiedades térmicas y acústicas y, fundamentalmente, bajo costo y gran disponibilidad. Los resultados obtenidos son bastante alentadores debido a la durabilidad y resistencia mecánica obtenidos a base del tratamiento proporcionado a la materia orgánica. Se comentan las aplicaciones actuales y futuras de estos nuevos materiales.

  4. La Ciudad bajo el neoliberalismo

    Directory of Open Access Journals (Sweden)

    Jaime Ornelas Delgado

    2000-01-01

    Full Text Available En este artículo se exponen algunas reflexiones referidas a los diversos impactos que el neoliberalismo ha tenido en las áreas urbanas en México. En una primera parte se analizan los aspectos esenciales del modelo económico neoliberal; en la segunda se exponen los efectos de este modelo en las ciudades, tanto los que ya están presentes como los que se prevé que puedan aparecer. Asimismo, se estudia cómo se ha organizado y ocupado el territorio en las ciudades bajo el modelo neoliberal y cuáles son las esenarios, tanto si prevalece dicho modelo, como en el caso del surgimiento de una organización social dispuesta de manera distinta.

  5. Tension Structure

    Science.gov (United States)

    1978-01-01

    The fabric structure pictured is the Campus Center of La Verne College, La Verne, California. Unlike the facilities shown on the preceding pages, it is not air-supported. It is a "tension structure," its multi-coned fabric membrane supported by a network of cables attached to steel columns which function like circus tent poles. The spider-web in the accompanying photo is a computer graph of the tension pattern. The designers, Geiger-Berger Associates PC, of New York City, conducted lengthy computer analysis to determine the the best placement of columns and cables. The firm also served as structural engineering consultant on the Pontiac Silverdome and a number of other large fabric structures. Built by Birdair Structures, Inc., Buffalo, New York, the La Verne Campus Center was the first permanent facility in the United States enclosed by the space-spinoff fabric made of Owens-Corning Beta fiber glass coated with Du Pont Teflon TFE. The flexible design permits rearrangement of the interior to accommodate athletic events, student activities, theatrical productions and other recreational programs. Use of fabric covering reduced building cost 30 percent below conventional construction.

  6. con bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Adriana Mora Antó

    2005-01-01

    Full Text Available Esta investigación dio cuenta de la relación entre el estilo de funcionamiento familiar, los patrones de crianza y las edades de desarrollo evolutivo en niños, nacidos con bajo peso. El estudio descriptivo correlacional se realizó con 41 niños y sus madres, aplicándose cuestionarios sobre funcionamiento familiar, prácticas de crianza y desarrollo infantil. Los resultados señalaron la existencia de un funcionamiento familiar caracterizado por una cohesión amalgamada y una adaptabilidad caótica, una disciplina complaciente, falta de control y de límites claros en la díada madre-hijo. Se trataba de familias monoparentales, donde la temprana edad de concepción, el madresolterismo y el apoyo de la familia extensa eran constantes. Las edades evolutivas registradas indicaron un desarrollo inferior a la edad cronológica, en la mayor parte de los casos; sin embargo, éstas tendieron a ser superiores al compararlas con la edades reales de los infantes. No se encontró una correlación estadísticamente significativa entre la edad de desarrollo y los diferentes factores del funcionamiento familiar para algunos de los rangos de edad considerados; sin embargo, no se lo descartó por completo, especialmente en lo referente al optimismo familiar

  7. The effect of corrosion on stained glass windows

    Directory of Open Access Journals (Sweden)

    Laissner, Johanna

    1996-06-01

    án seriamente amenazadas como obras de arte por la corrosiva influencia del ambiente. Este proceso de corrosión es muy complejo y no sólo está influido por los cambios de temperatura y de humedad, sino también por contaminantes gaseosos como el dióxido de azufre, óxidos de nitrógeno u ozono, por el polvo y el aire, por microorganismos y también por interacciones sinérgicas. Los vidrios de las vidrieras medievales se ven fuertemente afectados por estos ataques ambientales debido a su composición química, ya que contienen un porcentaje bajo de sílice y proporciones elevadas de iones modificadores (potasio y calcio. En la mayoría de los casos los fenómenos de corrosión aparecen como picaduras de la superficie donde se forman gruesas costras de corrosión que les confieren un aspecto opaco y que, por lo tanto, reduce bastante la transparencia de las vidrieras. Con el fin de establecer un concepto de conservación y restauración, se hace necesario conocer las condiciones medioambientales a las que las vidrieras están expuestas. Con este propósito se han desarrollado vidrios modelo muy sensibles a la corrosión (llamados vidrios sensores que poseen una composición química similar a la de los vidrieras históricas. Estos vidrios experimentan las mismas reacciones de corrosión, pero reaccionan mucho más rápidamente y se usan para estimar las tensiones debidas a la corrosión de las vidrieras afín de dar una información básica sobre el impacto de la corrosión cuando se trabaja con vidrios históricos.

  8. Corrosion protection

    Science.gov (United States)

    Brown, Donald W.; Wagh, Arun S.

    2003-05-27

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

  9. Lexicon and word formation in Indonesian Bajo

    Directory of Open Access Journals (Sweden)

    Chandra Nuraini

    2010-10-01

    Full Text Available This paper1 deals with the phonology and the lexicology of the Indonesian Bajo language and more specifically with the dialect or variant that can be heard all around the Flores Sea in Kangean, South-East Sulawesi, Sumbawa, and Flores. The phonological survey focuses on vowel lengthening, gemination, pre-nasalized phonemes, and sandhi. The second part of this paper proposes an insight into Bajo lexicology, restricted to nominal and verbal derivation.

  10. EFFECT OF CHLORIDE ON THE ATMOSPHERIC CORROSION OF SIMULATED ARTIFACT IRON IN NO3-BEARING POLLUTANT ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    X. Cao; C.C. Xu

    2006-01-01

    The effect of chloride in nitrogen-bearing pollutant on the atmospheric corrosion of cast iron was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test.Scanning electron microscopy (SEM) with energy disperse atomic X-ray (EDAX) was used to identify the corrosion processes and products. The results of the weight loss measurement showed that the whole corrosion kinetics can be approximately described by: AW=AtB. With the addition of NaC1, B increases. The result presented that Cl- accelerated the corrosion rate obviously during the whole corrosion process. The initial corrosion process was investigated from the viewpoint of surface tension. At the initial corrosion period, the corrosion rate was proportion to the adsorption of anions contained the solutions. And as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominant the corrosion process, which led to the accelerated effect.

  11. Corrosion Engineering.

    Science.gov (United States)

    White, Charles V.

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

  12. Corrosion sensor

    Science.gov (United States)

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

    1994-01-01

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

  13. Study of the sulphide stress corrosion cracking (SSCC) resistance of API SL GR B and X60 pipeline steels. Evaluacion de la resistencia al agrietamiento por corrosion-tension en medios sulfhidricos (SSCC) de aceros para tuberias Calidad API 5L Grados B y X60

    Energy Technology Data Exchange (ETDEWEB)

    Bao-Iturbe, C. (Babcock and Wilcox Espaola. S.A. Bilbao (Spain)); Gutierrez de Saiz-Solabarria (Univ. Pais Vasco. Departamento Ingenieria Metalurgica y Control de Materiales. Bilbao (Spain))

    1993-01-01

    A study of the sulphide stress corrosion cracking resistance at room temperature of API 5L Cr B and X60 pipeline steels has been carried out. The theoretical mechanisms in order to explain these phenomena and several operational failures of pipeline steel due to SSCC have been reviewed and the National Association of Corrosion Engineers (NACE) standard concerning SSCC has been described. The main factors of influence of the SSCC have been analysed, results are presented and conclusions are elaborated. (Author) 32 ref.

  14. Characterization by EBSD technique of AISI 304 DDQ stainless steel sheet deformed under typical deep drawing multiaxial stress system; Caracterizacion mediante la tecnica EBSD de la defromacion de chapa de acero inoxidable AISI 304 DDQ bajo tensiones multiaxiales tipicas de la embuticion

    Energy Technology Data Exchange (ETDEWEB)

    Coello, J.; Miguel, V.; Calatayud, A.; Ferrer, C.; Martinez, A.

    2009-07-01

    The main aim of this work to evaluate AISI 304 DDQ stainless steel behaviour under deep drawing deformation condition, that is pure shear deformation in which materials suffers a typical deformation under tension-biaxial compression stresses system. The microstructural evolution has been investigated by optical microscopy and by EBSD technique. The success of the EBSD analysis has been established for the deformation conditions experimented here. It has been determined the rolling direction and the equivalent strain influence on the crystallographic orientation maps, misorientation diagrams and poles figures. The results let the authors say the low angle misorientation corresponding to 0,45 and 90 degree centigrade rolling directions have an inverse correlation with the material anisotropy. Initial pre-straining has been considered also and the analysis of this aspects lead to establish that the increment of the intragranular misorientation with the strain depends on the initial state a of the steel; this increment is observed to be minor for samples with initial prestraining. High angle misorientation analysis (>15 degree centigrade) indicates that the grain boundaries character distributions depends on the deformation. (Author) 20 refs.

  15. Skin tension related to tension reduction sutures.

    Science.gov (United States)

    Hwang, Kun; Kim, Han Joon; Kim, Kyung Yong; Han, Seung Ho; Hwang, Se Jin

    2015-01-01

    The aim of this study was to compare the skin tension of several fascial/subcutaneous tensile reduction sutures. Six upper limbs and 8 lower limbs of 4 fresh cadavers were used. At the deltoid area (10 cm below the palpable acromion) and lateral thigh (midpoint from the palpable greater trochanter to the lateral border of the patella), and within a 3 × 6-cm fusiform area of skin, subcutaneous tissue defects were created. At the midpoint of the defect, a no. 5 silk suture was passed through the dermis at a 5-mm margin of the defect, and the defect was approximated. The initial tension to approximate the margins was measured using a tensiometer.The tension needed to approximate skin without any tension reduction suture (S) was 6.5 ± 4.6 N (Newton). The tensions needed to approximate superficial fascia (SF) and deep fascia (DF) were 7.8 ± 3.4 N and 10.3 ± 5.1 N, respectively. The tension needed to approximate the skin after approximating the SF was 4.1 ± 3.4 N. The tension needed to approximate the skin after approximating the DF was 4.9 ± 4.0 N. The tension reduction effect of approximating the SF was 38.8 ± 16.4% (2.4 ± 1.5 N, P = 0.000 [ANOVA, Scheffé]). The tension reduction effect of approximating the DF was 25.2% ± 21.9% (1.5 ± 1.4 N, P = 0.001 [ANOVA, Scheffé]). The reason for this is thought to be that the SF is located closely to the skin unlike the DF. The results of this study might be a basis for tension reduction sutures.

  16. Study on the Synthesis and Corrosion Inhibition Performance of Mannich-Modified Imidazoline

    Directory of Open Access Journals (Sweden)

    Xiangjun Kong

    2016-07-01

    Full Text Available A novel Mannich-modified imidazoline (MMI as cationic emulsifier was synthesised for corrosion harm reduction, through three steps — acylation, cyclization, and Mannich reaction. The surface activity was characterized by determination of surface tensions and critical micelle concentration (CMC. The corrosion inhibition performance of five types of steels in the simulated corrosion solution in the presence of the MMI was investigated by static weight loss tests. The results showed that the MMI had good surface activities, with CMC of 19.8 μg g−1 and surface tension of 36.4 mN m−1. The corrosion test results indicated that the corrosion rates of different materials were decreased significantly, and degrees of corrosion inhibition were always higher than 80.0 %. The main inhibition mechanism was most likely due to the adsorption of the corrosion inhibitor on the steel surface, leading to the prevention of corrosion medium from the metal surface.

  17. Cine DSLR y de bajo presupuesto

    OpenAIRE

    Modino Sicilia, Vicente

    2014-01-01

    El autor hace un recorrido por las diferentes cámaras de cine utilizadas en la industria cinematográfica, para centrarse al final en las cámaras DSLR que permiten realizar películas a muy bajo presupuesto y con una calidad aceptable

  18. The intangible legacy of the Indonesian Bajo

    Directory of Open Access Journals (Sweden)

    Chandra Nuraini

    2016-05-01

    Full Text Available The Sama-Bajau, or Bajo diaspora, extends from the southern Philippines and Sabah (Malaysian Borneo to the eastern part of Indonesia. The Indonesian Bajo, now scattered along the coasts of Sulawesi (Celebes and East Kalimantan, the Eastern Lesser Sunda Islands and Maluku, were once mostly nomadic fishermen of the sea or ocean freight carriers. Today, the Bajo are almost all fishermen and settled. Their former and present ways of life made them favour intangible forms of culture: it is impossible to transport bulky artefacts when moving frequently by boat, or when living in stilt houses, very close to the sea or on a reef. It is therefore an intangible legacy that is the essence of the Bajo’s culture. Sandro healers have a vast range of expertise that allows them to protect and heal people when they suffer from natural or supernatural diseases. On the other hand, music and especially oral literature are very rich. In addition to song and the pantun poetry contests, the most prestigious genre is the iko-iko, long epic songs that the Bajo consider to be historical rather than fictional narratives. The Bajo’s intangible heritage is fragile, since it is based on oral transmission. In this article, I give a description of this heritage, dividing it into two areas: the knowledge that allows them to “protect and heal” on the one hand, and to “distract and relax”, on the other.

  19. Corrosion in airframes

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  20. CORROSION IN AIRFRAMES

    OpenAIRE

    PETROVIC ZORAN C.

    2016-01-01

    The introductory chapter provides a brief reference to the issue of corrosion and corrosion damage to aircraft structures. Depending on the nature and dimensions of this non uniformity, three different categories of corrosion are defined: uniform, selective and localized corrosion. The following chapters present the forms of corrosion that can occur in three defined categories of corrosion. Conditions that cause certain types of corrosion in various corrosive environments are discussed. Examp...

  1. Collapse of Corroded Pipelines under Combined Tension and External Pressure.

    Directory of Open Access Journals (Sweden)

    Hao Ye

    Full Text Available In this work, collapse of corroded pipeline under combined external pressure and tension is investigated through numerical method. Axially uniform corrosion with symmetric imperfections is firstly considered. After verifying with existing experimental results, the finite element model is used to study the effect of tension on collapse pressure. An extensive parametric study is carried out using Python script and FORTRAN subroutine to investigate the influence of geometric parameters on the collapse behavior under combined loads. The results are used to develop an empirical equation for estimating the collapse pressure under tension. In addition, the effects of loading path, initial imperfection length, yielding anisotropy and corrosion defect length on the collapse behavior are also investigated. It is found that tension has a significant influence on collapse pressure of corroded pipelines. Loading path and anisotropic yielding are also important factors affecting the collapse behavior. For pipelines with relatively long corrosion defect, axially uniform corrosion models could be used to estimate the collapse pressure.

  2. Underground pipeline corrosion

    CERN Document Server

    Orazem, Mark

    2014-01-01

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

  3. Lignification and tension wood.

    Science.gov (United States)

    Pilate, Gilles; Chabbert, Brigitte; Cathala, Bernard; Yoshinaga, Arata; Leplé, Jean-Charles; Laurans, Françoise; Lapierre, Catherine; Ruel, Katia

    2004-01-01

    Hardwood trees are able to reorient their axes owing to tension wood differentiation. Tension wood is characterised by important ultrastructural modifications, such as the occurrence in a number of species, of an extra secondary wall layer, named gelatinous layer or G-layer, mainly constituted of cellulose microfibrils oriented nearly parallel to the fibre axis. This G-layer appears directly involved in the definition of tension wood mechanical properties. This review gathers the data available in the literature about lignification during tension wood formation. Potential roles for lignin in tension wood formation are inferred from biochemical, anatomical and mechanical studies, from the hypotheses proposed to describe tension wood function and from data coming from new research areas such as functional genomics.

  4. Corrosion Testing Facility

    Data.gov (United States)

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

  5. Corrosión bajo tensión en aceros para pretensado

    Directory of Open Access Journals (Sweden)

    del Pozo, Florencio

    1969-12-01

    Full Text Available This paper summarises the first results of a testing program to investigate behaviour of prestressing steels in corrosion. This work is being done at the Central Laboratory for Testing Construction Materials, of the Centre of Research and Experiments of Public Works. The tests confirm the belief that patented drawn steels are very suitable for prestressing, and that the phenomenon of corrosion under stress must be infrequent in practice, if the work is well done. The most aggressive agents are those which provoke fragilization through hydrogen, the most frequent being SH2. Nitrates, which are often cited as typical corrosion agents associated to stress, are less dangerous than SH2. Tempered and case hardened steels are more susceptible to these attacks than cold drawn steels. Chlorates have turned out to be less dangerous than nitrates. After prolonged tests no failure has been recorded due to corrosion under stress. The purpose of this investigation is to develop a simple and representative test for the phenomenon of corrosion under stress and fragilization due to hydrogen, so that this test may complement the normal ones that are applied to classify steel.En este trabajo se resumen los primeros resultados de un plan de ensayos, para investigar el comportamiento frente a la corrosión de los aceros para pretensado, que está realizando el Laboratorio Central de Ensayo de Materiales de Construcción del Centro de Estudios y Experimentación de Obras Públicas. Los ensayos confirman el criterio de que los aceros patentados y trefilados reúnen buenas condiciones para su uso en pretensado y que el fenómeno de corrosión bajo tensión debe ser poco frecuente en la práctica, si la obra está bien realizada. Los agentes más agresivos son los que provocan fragilización por hidrógeno; el más frecuente es el SH2. Los nitratos, citados frecuentemente como agentes típicos de corrosión bajo tensión, son menos peligrosos que el SH2. Los aceros

  6. Tension chylothorax following pneumonectomy

    Directory of Open Access Journals (Sweden)

    Hemang Yadav

    2015-01-01

    Full Text Available Post-pneumonectomy chylothorax is an uncommon complication following surgery, with an estimated incidence of less than 0.7%. Post-pneumonectomy tension chylothorax, where rapid accumulation of chyle in the post-pneumonectomy space results in hemodynamic compromise, is exceedingly rare, with just 7 cases previously reported. All prior cases of tension chylothorax were managed operatively with decompressive chest tube placement followed by open thoracic duct repair. Our case is the first reported tension chylothorax to be managed conservatively by thoracostomy drainage coupled with a period of parenteral nutrition followed by a medium chain triglyceride-restricted diet.

  7. Aircraft Corrosion

    Science.gov (United States)

    1981-08-01

    allowed to dry. The area is then checked for the golden brown color which is produced by the chemical conversion material. If the work area requires...Materials, pp. 258-3074 1968. 41. W. IH. Ailor, "Seven-year exposure at Point leyes , California," "Corrosion in Natural Environments, ASTM STP 558," American... Color Units 3 Turbidity Units 0.7 pH Units 7.6 Temperature OF 76 Sp. Conductivity MMhos 425 B.O.D. (5 days at 206C) 0.2 SjV i;~-- 1201 A .9 8 ~ 8 kl

  8. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    la Cour, M; Kiilgaard, Jens Folke; Eysteinsson, T

    2000-01-01

    To investigate the influence of acute changes in intraocular pressure on the oxygen tension in the vicinity of the optic nerve head under control conditions and after intravenous administration of 500 mg of the carbonic anhydrase inhibitor dorzolamide....

  9. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced can

  10. Results of monitoring large carbon fiber post-tensioning systems in a balanced Cantilever Brdige (Dintelharbour Bridge, The Netherlands)

    NARCIS (Netherlands)

    Vervuurt, A.H.J.M.; Kaptijn, N.; Hageman, J.G.; Kuilboer, C.P.M.

    2012-01-01

    Steel post-tensioning systems and stay cables are susceptible to corrosion. Carbon fiber systems are not. However, there was no experience on the long term behavior of such post-tensioned elements. Four external tendons (75 m long), stressed to a load of 2650 kN, were applied in a large balanced

  11. Blood Vessel Tension Tester

    Science.gov (United States)

    1978-01-01

    In the photo, a medical researcher is using a specially designed laboratory apparatus for measuring blood vessel tension. It was designed by Langley Research Center as a service to researchers of Norfolk General Hospital and Eastern Virginia Medical School, Norfolk, Virginia. The investigators are studying how vascular smooth muscle-muscle in the walls of blood vessels-reacts to various stimulants, such as coffee, tea, alcohol or drugs. They sought help from Langley Research Center in devising a method of measuring the tension in blood vessel segments subjected to various stimuli. The task was complicated by the extremely small size of the specimens to be tested, blood vessel "loops" resembling small rubber bands, some only half a millimeter in diameter. Langley's Instrumentation Development Section responded with a miniaturized system whose key components are a "micropositioner" for stretching a length of blood vessel and a strain gage for measuring the smooth muscle tension developed. The micropositioner is a two-pronged holder. The loop of Mood vessel is hooked over the prongs and it is stretched by increasing the distance between the prongs in minute increments, fractions of a millimeter. At each increase, the tension developed is carefully measured. In some experiments, the holder and specimen are lowered into the test tubes shown, which contain a saline solution simulating body fluid; the effect of the compound on developed tension is then measured. The device has functioned well and the investigators say it has saved several months research time.

  12. Surface Tension of Spacetime

    Science.gov (United States)

    Perko, Howard

    2017-01-01

    Concepts from physical chemistry and more specifically surface tension are introduced to spacetime. Lagrangian equations of motion for membranes of curved spacetime manifold are derived. The equations of motion in spatial directions are dispersion equations and can be rearranged to Schrodinger's equation where Plank's constant is related to membrane elastic modulus. The equation of motion in the time-direction has two immediately recognizable solutions: electromagnetic waves and corpuscles. The corpuscular membrane solution can assume different genus depending on quantized amounts of surface energy. A metric tensor that relates empty flat spacetime to energetic curved spacetime is found that satisfies general relativity. Application of the surface tension to quantum electrodynamics and implications for quantum chromodynamics are discussed. Although much work remains, it is suggested that spacetime surface tension may provide a classical explanation that combines general relativity with field theories in quantum mechanics and atomic particle physics.

  13. Viviendas de bajo costo sistema SALVY

    Directory of Open Access Journals (Sweden)

    Suárez Ibarra, Salvador

    1984-06-01

    Full Text Available The aim of this work is to offer an alternative for solving the current problem of housing, through a building system which has been developed and tested in our country — the SAL VY SYSTEM. It is directed towards solving the problem of low-cost housing with own technology, enabling these houses to be built quickly, using materials which are not traditional in building, but are abundant in our country. The house presented by us allows the user to extend its height according to his needs and financial possibilities, keeping the free area of the plot for so-called kitchen gardens.Este trabajo tiene como objetivo presentar una alternativa para la solución del problema actual de la vivienda, a través de un sistema constructivo desarrollado y experimentado en nuestro país —SISTEMA SALVY, dirigido a solucionar el problema de la vivienda de bajo costo, con una tecnología propia que permite la construcción de estas viviendas de una manera rápida, utilizando materiales no tradicionales en construcción, pero abundantes en nuestro país. La vivienda que presentamos permite al usuario ampliarla en altura, de acuerdo a sus necesidades y posibilidades económicas, manteniendo el área libre de la parcela para los denominados huertos del hogar.

  14. The Tension Literature.

    Science.gov (United States)

    Frederick, A. B.

    This is a bibliography of literature on the subject of tension. Books, films, and periodicals with a bearing on stress, relaxation, anxiety, and/or methods of controlling stress are listed from the fields of physiology, psychology, and philosophy. New methods such as transcendental meditation and biofeedback are analyzed briefly and criteria are…

  15. Rein tension during canter

    NARCIS (Netherlands)

    Egenvall, Agneta; Eisersiö, Marie; Rhodin, Marie; van Weeren, P.R.; Roepstorff, Lars

    2015-01-01

    Riders generally use reins as a means for communication with the horse. At present, the signalling pattern is poorly understood. The aim of this study was to illustrate and analyse the rein tension patterns in a number of rider/horse combinations across a variety of exercises in the canter gait. Our

  16. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta...

  17. Optic nerve oxygen tension

    DEFF Research Database (Denmark)

    Kiilgaard, Jens Folke; Pedersen, D B; Eysteinsson, T

    2004-01-01

    The authors have previously reported that carbonic anhydrase inhibitors such as acetazolamide and dorzolamide raise optic nerve oxygen tension (ONPO(2)) in pigs. The purpose of the present study was to investigate whether timolol, which belongs to another group of glaucoma drugs called beta block...

  18. Restos de vida en Bajo este sol tremendo de Carlos Busqued

    Directory of Open Access Journals (Sweden)

    Marcos Seifert

    2017-07-01

    Full Text Available Este trabajo se propone analizar cómo la novela de Carlos Busqued Bajo este sol tremendo (2009 se apoya en la representación de vidas desechadas, basura y todo tipo de restos para instalarse en una tensión entre orden y exceso. La narración plantea una lógica en la que la basura, en lugar de constituirse en un indicio que posibilite la reconstrucción del paisaje social, exhibe lo desbordante, lo inasimilable y los vacíos de sentido. En el mundo que nos presenta Busqued lo viviente se vuelve resto en la medida en que encarna una heterogeneidad irreductible a cualquier estructura social y productiva. This paper analyzes the way in which Carlos Busqued's novel Bajo este sol tremendo (2009 is based on the representation of discarded lives, garbage, and all kinds of remains and thus proposes a tension between order and excess. The narration raises a logic in which garbage, instead of constituting an indicator that allows for the reconstruction of the social landscape, exhibits the overflowing, the unassimilable, and the voids of meaning. In the world that Busqued presents, the living becomes a remainder because it embodies an irreducible heterogeneity with regards to any social and productive structure.

  19. Túnel bajo el Elba - Hamburgo - Alemania Federal

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1976-03-01

    Full Text Available This important work, constructed to solve the traffic problem between the northern and Southern parts of Hamburg, has an overall length of 3,325 m. The greater part of the tunnel is provided with special aeration, supplied by three ventilation stations. The tunnel is made up of three independent! circulation tubes, each with two traffic lanes. The lateral tubes are intended for one way traffic, whereas the middle lane is designed for two way traffic. In the section under the river itself, these three tubes, along with the ventilating ducts, come together into one single rectangular piece. This particular stretch consists of eight members, which were constructed in nearby dry dock and were later sunk and laid on the river bottom, along a previously excavated trench. It was completed by means of highly advanced technological methods for sealing the joints and subsequently the trench was again covered up with the excavation material. The section under the greatest slope of the river bed was excavated by means of the method of the advancing driller pipe shield, and the end sections were so near the surface that the work was carried out in the open air. The northern ventilation station —a reinforced concrete construction, connecting sections of the tunnel— further contains the safety and control stations for the entire length of the tunnel, and is equipped with the most modern technical devices.Esta importante obra, construida para solucionar el problema del tráfico entre las zonas norte y sur de la ciudad de Hamburgo, tiene una longitud total de 3.325 m. En la mayor parte de su recorrido se utiliza un sistema de aireación especial, abastecido por tres estaciones de ventilación. El túnel está constituido por tres tubos de circulación independientes, con dos carriles cada uno. Los tubos laterales se utilizan para el tráfico en un solo sentido, mientras que el central permite la circulación en ambas direcciones. En el tramo bajo

  20. Coulomb string tension, asymptotic string tension, and the gluon chain

    Science.gov (United States)

    Greensite, Jeff; Szczepaniak, Adam P.

    2015-02-01

    We compute, via numerical simulations, the nonperturbative Coulomb potential of pure SU(3) gauge theory in Coulomb gauge. We find that the Coulomb potential scales nicely in accordance with asymptotic freedom, that the Coulomb potential is linear in the infrared, and that the Coulomb string tension is about four times larger than the asymptotic string tension. We explain how it is possible that the asymptotic string tension can be lower than the Coulomb string tension by a factor of four.

  1. Durability ofAsphalt in Different Corrosion Solution

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuanfa; GUAN Bowen; XIONG Rui; SHENG Yanping; HE Rui

    2011-01-01

    The corrosion to asphalt mixture under different kinds of corrosion solution,such as pH=2 solution,pH=12 solution,pH =12 solution and 10% Na2SO4 solution,was studied.The performance attenuation of asphalt mixture was analyzed under the normal environment and the freeze-thaw environment,and the analysis was given on the sensitivity of the test results to the evaluation index.The experimental results show that the performance of asphalt mixture is attenuated faster under the acidic solution,alkaline solution and sulfate solution.Corrosion factor Kc,freeze-thaw corrosion factor Kf,and freeze-thaw effect factor Kfc are proposed to evaluate asphalt mixture resistance to corrosion in different kinds of corrosion solution.The values of Kc and Kfc decrease with the increasing of corrosion time.The change rule of Kf show that the rate of corrosion is decreased by the action of freeze-thaw in acidic solution and in alkaline solution,but is increased by the action of freeze-thaw in sulfate solution.The microscopic analysis indicates that acid solution reacts with aggregate of asphalt mixture,alkaline solution reacts with asphalt cement of asphalt mixture,the surface tension of sulfate solution and crystallization of sulfate are the main reasons which weak the performance of asphalt mixture.

  2. Modelling of Corrosion Cracks

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle

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

  3. Bajo materialismo y surrealismo El debate Bataille-Breton

    National Research Council Canada - National Science Library

    Denise Dunan, Noelia; Taurel Xifra, José

    2015-01-01

    ... en una máquina contra el surrealismo. El presente artículo desarrolla la formación de Bataille para hacer hincapié en la categoría de bajo materialismo construida en tensión entre el idealismo surrealista y los distintos materialismos. Así puede verse que Documents y el bajo materialismo conjugan las preocupaciones que perseguirá toda su vida.

  4. Management of Reinforcement Corrosion

    DEFF Research Database (Denmark)

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

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

  5. Corrosion inhibitors; Los inhibidores de corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Godinez, L. A.; Meas, Y.; Ortega-Borges, R.; Corona, A.

    2003-07-01

    In this paper, we briefly describe the characteristics, cost and electrochemical nature of the corrosion phenomena as well as some of the technologies that are currently employed to minimize its effect. The main subject of the paper however, deals with the description, classification and mechanism of protection of the so-called corrosion inhibitors. Examples of the use of these substances in different aggressive environments are also presented as means to show that these compounds, or their combination, can in fact be used as excellent and relatively cheap technologies to control the corrosion of some metals. In the last part of the paper, the most commonly used techniques to evaluate the efficiency and performance of corrosion inhibitors are presented as well as some criteria to make a careful and proper selection of a corrosion inhibitor technology in a given situation. (Author) 151 refs.

  6. Factores asociados al bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Georgina J Peraza Roque

    2001-10-01

    Full Text Available El bajo peso al nacer (BPN ha constituido un enigma en la ciencia a través de los tiempos. Múltiples son las investigaciones realizadas acerca de las causas que lo producen y las consecuencias que provoca. Su importancia no solo radica en lo que significa en la morbilidad y la mortalidad infantil, sino que estos niños tienen habitualmente múltiples problemas posteriores. El Programa para la Reducción del BPN señala que los niños nacidos con un peso inferior a los 2 500 g presentan riesgo de mortalidad 14 veces mayor durante el primer año de vida, en comparación con los niños que nacen con un peso normal a término. Dentro de los factores de riesgo del BPN se han encontrado con mayor frecuencia en estudios realizados por diferentes autores, los siguientes: el embarazo en la adolescencia, la desnutrición en la madre, el hábito de fumar, la hipertensión arterial durante el embarazo, la sepsis cervicovaginal, la anemia y los embarazos gemelares, entre otros. Es innegable la influencia que el BPN tiene sobre las futuras generaciones, por lo que debe constituir la diana de los esfuerzos que el médico y la enfermera deben desarrollar en su prevención, sobre todo en la comunidadLow birth weight has been an enigma for Science through times. A lot of research works have been carried out about its causes and consequences. The importance of LBW not only lies in its meaning for infant mortality and morbidity but also in the many problems that low birth weight children regularly face in the future. The program for the reduction of LBW points out that newborns weighing under 2500g have during his/her first year of life a mortality risk 14 times higher than newborns with a normal weight at term. Among the low birth weight risk factors, a number of studies by various authors have frequently found the following; pregnancy at adolescence; undernourishment in mothers, smoking, blood hypertension during pregnancy, cervix-vaginal sepsis; anemia, twin

  7. Túnel bajo el puerto de Boston

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1963-05-01

    Full Text Available The new tunnel under Boston harbour has been constructed because of the insufficient capacity of a similar, earlier, tunnel to cope with the ever increasing road traffic. This tunnel is 1,550 ms long, and 9.50 ms in external diameter. There are two traffic lanes, each 3.20 ms wide. Inside it is faced with ceramic tiles, has fluorescent lighting, and ventilation is maintained by means of two ducts, one at each entrance, where the necessary compressor and other equipment has been situated. The most interesting feature of this important project is the excavation method adopted for its construction: the tunnel crosses a clay layer, which at certain places is sufficiently fluid to allow a pneumatic shield to be forced through it leaving hardly any debris behind. It will be readily appreciated that this procedure shows an obvious advantage over ordinary methods, in which it is necessary to cut out, and transport to the exterior all the excavated material. The metal sheathing was by the Commercial Shearing and Stamping Co., Youngstown, Ohio.Este nuevo túnel, bajo el puerto de Boston, es una consecuencia de la necesidad imperiosa que se hacía sentir dada la insuficiente capacidad del otro túnel similar antiguo y el aumento continuo del tráfico urbano y por carretera. Tiene 1.550 m de longitud, 9,50 m de diámetro exterior y una calzada con dos bandas de circulación de 3,20 m de anchura cada una. Está revestido ccn baldosa cerámica, iluminado con luz fluorescente, y el aire viciado se ventila y renueva por medio de dos torres de ventilación—una en cada portal—, en las que se han instalado el equipo mecánico adecuado de ventilación y compresores. La parte más interesante de esta importante obra estriba en los procedimientos empleados para llevar a cabo la excavación, pues atraviesa un banco de arcilla que, en ciertos tramos, es suficientemente fluida para permitir dejarse empujar y ceder paso a un escudo neumático que avanza sin apenas

  8. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

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

  9. Effect of Chloride on the Atmospheric Corrosion of Cast Iron in Sulphur or Nitrogen-Bearing Pollutant Environment%氯离子在含硫氮污染物的环境中对模拟铁器文物的大气腐蚀的影响

    Institute of Scientific and Technical Information of China (English)

    曹霞; 许淳淳

    2005-01-01

    The effect of chloride on the atmospheric corrosion of cast iron in sulphur or nitrogen-bearing pollutant was investigated by using periodic wet-dry test, electrochemical experiment and surface tension test. Scanning electron microscopy coupled with energy dispersive atomic (EDAX) and stereoscopic microscopy was used to identify the corrosion processes and products. Cl- and NO-3 were shown accelerating effects during the whole corrosion process but depression effects were observed in Cl- and HSO-3 bearing pollutant at the initial corrosion stage.However, with the corrosion going on, the depression effects was less obviously and the initial corrosion process was investigated from the viewpoint of surface activity. At the initial corrosion stage, the corrosion rate was proportional to the adsorptivity of anions, but as corrosion went on, the penetration effect of anions and different characteristics of the corrosion products began to dominate the corrosion process, which led to changes on the corrosion rate.

  10. Gente de agua: Comunidades negras en el Bajo Atrato

    Directory of Open Access Journals (Sweden)

    Daniel Ruíz Serna

    2010-05-01

    Full Text Available “Gente de agua” es un conjunto de imágenes sobre el universo social de las comunidades negras del Bajo Atrato chocoano. Ilustra de forma sensible el sistema de texturas de la vida negra en el río. Desde las pieles brillantes bajo el sol, pasando por todos los colores del agua, hasta la ignominiosa condena del racismo y la exclusión son objeto del lente del etnógrafo que ha encontrado en las imágenes una opción para hacer antropología.

  11. Electrochemical corrosion studies

    Science.gov (United States)

    Knockemus, W. W.

    1986-01-01

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

  12. Erosion-corrosion; Erosionkorrosion

    Energy Technology Data Exchange (ETDEWEB)

    Aghili, B

    1999-05-01

    A literature study on erosion-corrosion of pipings in the nuclear industry was performed. Occurred incidents are reviewed, and the mechanism driving the erosion-corrosion is described. Factors that influence the effect in negative or positive direction are treated, as well as programs for control and inspection. Finally, examples of failures from databases on erosion-corrosion are given in an attachment 32 refs, 16 figs, tabs

  13. Corrosión bajo tensión de aceros eutectoides con trefilado progresivo

    Directory of Open Access Journals (Sweden)

    Ovejero, E.

    1998-05-01

    Full Text Available The consequences of the microstructural evolution in an eutectoid steel that has undergone a cold drawing process are studied. This manufacturing technique produces changes in the steel microstructure: a progressive orientation and slenderising of the pearlite colonies and an orientation and packing of the pearlite lamellae, thus reducing the interlamellar spacing. In addition, the experimental results of the stress corrosion cracking tests show that cold drawing produces resistant anisotropy in the steel and thus the stress corrosion cracking resistance is a directional property which seems to depend on the orientation of the microstructure in relation to the cold drawing direction. As a consequence, a transversal crack tends to change its propagation direction approaching the wire axis and a crack growth in mode I evolves to a mixed mode propagation.

    Se estudian las consecuencias de la evolución microestructural en un acero eutectoide que ha sufrido un proceso de trefilado progresivo. Esta técnica de fabricación origina una serie de cambios en la microestructura del acero: una orientación progresiva y un estiramiento de las colonias de perlita y una orientación y densificación de las láminas de perlita, reduciendo así el espaciado interlaminar. Por otra parte, los resultados experimentales de los ensayos de corrosión bajo tensión demuestran que el trefilado produce anisotropía resistente en el acero, y así la resistencia a la corrosión bajo tensión es una propiedad direccional que parece depender de la orientación de la microestuctura con respecto a la dirección del trefilado. Como consecuencia, una fisura transversal tiende a cambiar su dirección de propagación para aproximarse a la del eje del alambre, y un crecimiento en modo I evoluciona hacia una propagación en modo mixto.

  14. Coatings and Corrosion Laboratory

    Data.gov (United States)

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

  15. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  16. Corrosion in the oil industry

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-04-01

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

  17. Fragmentation in Biaxial Tension

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, G H; Archbold, G C; Hurricane, O A; Miller, P L

    2006-06-13

    We have carried out an experiment that places a ductile stainless steel in a state of biaxial tension at a high rate of strain. The loading of the ductile metal spherical cap is performed by the detonation of a high explosive layer with a conforming geometry to expand the metal radially outwards. Simulations of the loading and expansion of the metal predict strain rates that compare well with experimental observations. A high percentage of the HE loaded material was recovered through a soft capture process and characterization of the recovered fragments provided high quality data, including uniform strain prior to failure and fragment size. These data were used with a modified fragmentation model to determine a fragmentation energy.

  18. Tension-filled Governance?

    DEFF Research Database (Denmark)

    Celik, Tim Holst

    Since the crisis-engrossed 1970s, and especially the 1990s, ‘governance’ has become a dominant concern and concept; notably, within particularly political science, a certain diagnosis explicitly or implicitly focused on a shift ‘from government to governance’ has become increasingly popular....... This study examines the governance phenomenon of the post-1970/1990s period from a state-situated and historically informed perspective. Specifically, taking initial analytical departure in an approach of the early 1970s associated with James O’Connor, Jürgen Habermas and Claus Offe focused...... on the statesituated tension-filled functional relationship between legitimation and accumulation, the study both historically and theoretically reworks this approach and reapplies it for the post-1970s/1990s governance period. It asks whether and to what extent governance has served as a distinctive post- 1970s/1990s...

  19. Social and environmental tensions

    DEFF Research Database (Denmark)

    Saito, Moeko; Rutt, Rebecca Leigh; Chhetri, Bir Bahadur Khanal

    2014-01-01

    them, receive payments not only to address inequities but also for resource conservation. Drawing on a case study of a NORAD pilot project in Nepal, this paper investigates how affirmative measures adopted under the project affect different social actors and their perceptions and behaviors in relation......REDD + is a mitigation measure against global climate change that offers payments to developing countries based on the increased volume of forest carbon. It has been argued that affirmative measures should be adopted to ensure that communities, particularly the socially disadvantaged groups among...... to forests. Our case highlights the risk that the mere application of affirmative measures may give rise to difficult social and environmental tensions. Thus, this paper calls for such measures to effectively incorporate local perspectives in their designs and to be reflective, by allowing for regular...

  20. Research on Web Press Tension Control System

    OpenAIRE

    Chen Sheng Jiang; Zhang Chun Feng; Wang Zhong You; Li Qing Lin

    2016-01-01

    Tension control of press is a key and difficult point of the whole machine control. The stand or fall of tension is directly related to the quality of the products. According to the characteristics of the web press tension control, this paper expounds the main factors influencing tension and the purpose of tension control, researches on the tension control principle of web tape, analyzes control rule and control circuit of tension control system, illustrates the advantages of PID control law ...

  1. El justiprecio expropiatorio en los Países Bajos

    NARCIS (Netherlands)

    Muñoz Gielen, D.

    2009-01-01

    La plusvalía urbanística en los Países Bajos pertenece al propietario del suelo. La legislación expropiatoria es coherente con este principio al reconocer al propietario el derecho a un justiprecio que incluye la revalorización del suelo originada por su futuro uso. Desde finales de los 80, cuando l

  2. El justiprecio expropiatorio en los Países Bajos

    NARCIS (Netherlands)

    Muñoz Gielen, D.

    2009-01-01

    La plusvalía urbanística en los Países Bajos pertenece al propietario del suelo. La legislación expropiatoria es coherente con este principio al reconocer al propietario el derecho a un justiprecio que incluye la revalorización del suelo originada por su futuro uso. Desde finales de los 80, cuando l

  3. El justiprecio expropiatorio en los Países Bajos

    NARCIS (Netherlands)

    Muñoz Gielen, D.

    2009-01-01

    La plusvalía urbanística en los Países Bajos pertenece al propietario del suelo. La legislación expropiatoria es coherente con este principio al reconocer al propietario el derecho a un justiprecio que incluye la revalorización del suelo originada por su futuro uso. Desde finales de los 80,

  4. Carbon Dioxide Corrosion:

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup

    2008-01-01

    CO2 corrosion is a general problem in the industry and it is expensive. The focus of this study is an oil gas production related problem. CO2 corrosion is observed in offshore natural gas transportation pipelines. A general overview of the problem is presented in chapter 1. The chemical system co...

  5. Corrosion evaluation technology

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-09-01

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

  6. Avionics Corrosion Control Study

    Science.gov (United States)

    1974-01-01

    found at seacoast (harsn) environnents is the most destructive. Differences in electrolte concentration and oxygen concentration promote corrosion...against corrosion by acting as moisture and gas barriers. CMCVIT B0.4ID *COATINGS Polyurethane’s, cprxies, silicones, and polystyrenes are the most

  7. La organización social en los barrios bajos

    Directory of Open Access Journals (Sweden)

    William Foote Whyte

    2010-07-01

    Full Text Available

    Por mucho tiempo, los sociólogos han estudiado los barrios bajos en términos de desorganización social. El interés en los mismos parece provenir de dos fuentes: una urgencia por promover reformas sociales y un esfuerzo para comprender el proceso de urbanización. Observando el quiebre de los controles del grupo primario en la vida de ciudad, algunos sociólogos han considerado analizar la situación resultante en términos del concepto de desorganización social. Los barrios bajos han sido caracterizados por ciertos sociólogos, como áreas de almas perdidas y misiones, áreas donde individuos y familias viven en intimidad forzada con personas a las cuales normalmente rechazan y evitan; áreas donde no se aprecian estándares de decencia o buena conducta excepto los impuestos por una autoridad externa. Según la opinión de otros sociólogos, los barrios bajos son un área de libertad e individualismo. Harvey Zorbaugh dice que la política en el distrito bajo no es como la política en el distrito de clase media. Como no se ajusta a los estándares de la clase media, no es más que un juego. Más aún, la preocupación con el estudio de la desorganización familiar ha conducido a algunos sociólogos a subestimar cualquier grado de organización que se pueda encontrar en los barrios bajos

  8. Research on Web Press Tension Control System

    Directory of Open Access Journals (Sweden)

    Chen Sheng Jiang

    2016-01-01

    Full Text Available Tension control of press is a key and difficult point of the whole machine control. The stand or fall of tension is directly related to the quality of the products. According to the characteristics of the web press tension control, this paper expounds the main factors influencing tension and the purpose of tension control, researches on the tension control principle of web tape, analyzes control rule and control circuit of tension control system, illustrates the advantages of PID control law adopted in the tension control system, and concludes the influencing factors of paper tape tension control system and the corresponding problems needed to solve in the control.

  9. Longwall AFC chain tension meter

    Energy Technology Data Exchange (ETDEWEB)

    Peter Lugg; Zhiqiang Guan; Bart Pienaar [CRC Mining (Australia)

    2008-02-15

    Evaluation of the downtime statistics of two longwall mines studied as part of the Landmark Automation Project showed that AFC (Armoured Face Conveyor) and BSL (Beam Stage Loader) chain related failures accounted for 27% of all downtime. A chain tension meter was designed, certified Ex ia for use in ERZ0 sections of Australian coal mines and successfully field trialled on a longwall face during production. The dynamic behaviour and unequal sharing of load between the chains were recorded and found to be significant. The changing format of tension distribution around the conveyor as it is loaded was recorded and the implications of the change in the location of the point of minimum tension from tailgate to maingate as the conveyor is unloaded emphasised. The trial was run monitoring AFC chain tensions over a few shifts. The project successfully demonstrated that the measurement of AFC chain tensions on a working face can be achieved reliably.

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

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    2006-01-01

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

  11. Effects of Temperature on the Slow Strain Rate Tension Stress Corrosion Cracking of Super 13Cr Tubing Steel%温度对超级13Cr油管钢慢拉伸应力腐蚀开裂的影响

    Institute of Scientific and Technical Information of China (English)

    姚小飞; 谢发勤; 吴向清; 王毅飞

    2012-01-01

    Effects of temperature on the stress corrosion cracking of super 13Cr tubing steel were investigated in 3. 5% NaCl,that tensile strength and elongation and cracking time and stress corrosion cracking susceptibility index kscc and fracture morphology were analyzed by slow strain rate tensile stress corrosion cracking (SSRT) experiment method and σ-ε curve and SEM. The results shows that the degree of stress corrosion were lesser at below 60℃ and were severe at higher 80 ℃. With the rise of temperature, the super 13Cr tubing steel tensile strength decreased,e-longation rate decreased, contraction ratio decreases, breaking time was reduced, stress corrosion cracking tendency of increase, the stress corrosion cracking susceptibility index kσ and kε are increasing, and the increased trend of kε were obviously than kσ, effects of temperature on the plastic deformation of super 13Cr tubing steel were greater than the tensile strength.%采用慢应变速率拉伸(SSRT)应力腐蚀开裂试验方法,通过σ-ε曲线和SEM等分析了超级13Cr油管钢抗拉强度、延伸率、断裂时间、应力腐蚀开裂敏感性指数(kSCC)和断口形貌;研究了温度对其在3.5% NaCl溶液中应力腐蚀开裂(SCC)的影响.结果表明:当温度<60℃时应力腐蚀的程度较轻;当温度>80℃时应力腐蚀的程度严重;随温度的升高,超级13Cr油管钢的抗拉强度降低,延伸率减小,断面收缩率减小,断裂时间减小,应力腐蚀开裂的倾向性增大,应力腐蚀开裂敏感性指数kσ和kε均呈现增大的趋势,且kε比kσ增大的趋势更显著;温度对超级13Cr油管钢的塑性变形性的影响比对抗拉强度的影响更大.

  12. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    OpenAIRE

    Xuming Zhang; Guosong Wu; Xiang Peng; Limin Li; Hongqing Feng; Biao Gao; Kaifu Huo; Chu, Paul K.

    2015-01-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface c...

  13. Corrosion Failures in Marine Environment

    Directory of Open Access Journals (Sweden)

    R. Krishnan

    1985-04-01

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

  14. Corrosion Inhibitors for Reinforced Concrete

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Steel corrosion in reinforced concrete structures has been a major problem across the U.S. Steel-reinforced concrete structures are continually subject to attack by corrosion brought on by naturally occurring environmental conditions. FerroGard, a corrosion inhibitor, developed by Sika Corporation, penetrates hardened concrete to dramatically reduce corrosion by 65% and extend the structure's service life.

  15. Automated Methods Of Corrosion Measurements

    DEFF Research Database (Denmark)

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

    1997-01-01

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

  16. The Corrosion and Preservation of Iron Antiques.

    Science.gov (United States)

    Walker, Robert

    1982-01-01

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

  17. Bond Tension in Tethered Macromolecules.

    Science.gov (United States)

    Sheiko, Sergei S; Panyukov, Sergey; Rubinstein, Michael

    2011-06-14

    The paper presents scaling analysis of mechanical tension generated in densely branched macromolecules tethered to a solid substrate with a short linker. Steric repulsion between branches results in z-fold amplification of tension in the linker, where z is the number of chain-like arms. At large z ~ 100-1000, the generated tension may exceed the strength of covalent bonds and sever the linker. Two types of molecular architectures were considered: polymer stars and polymer "bottlebrushes" tethered to a solid substrate. Depending on the grafting density, one distinguishes the so-called mushroom, loose grafting, and dense grafting regimes. In isolated (mushroom) and loosely tethered bottlebrushes, the linker tension is by a factor of [Formula: see text] smaller than the tension in a tethered star with the same number of arms z. In densely tethered stars, the effect of interchain distance (d) and number of arms (z) on the magnitude of linker tension is given by f ≅ f0z(3/2)(b/d) for stars in a solvent environment and f ≅ f0z(2) (b/d)(2) for dry stars, where b is the Kuhn length and f0 ≅ kBT/b is intrinsic bond tension. These relations are also valid for tethered bottlebrushes with long side chains. However, unlike molecular stars, bottlebrushes demonstrate variation of tension along the backbone f ≅ f0s z(1/2) / d as a function of distance s from the free end of the backbone. In dense brushes [Formula: see text] with z ≅ 1000, the backbone tension increases from f ≅ f0 = 1 pN at the free end of the backbone (s ≅ b) to its maximum f ≅ zf0 ≅ 1 nN at the linker to the substrate (s ≅ zb).

  18. Giant bullae mimicking tension pneumothorax

    Directory of Open Access Journals (Sweden)

    Ahmet Erbey

    2012-12-01

    Full Text Available Giant bullae may mimic tension pneumothorax radiologicallyso that it may expand completely to hemithorax,increase of radiolucency mediastinal shift, flattening ofdiaphragm and printing on trachea. Sixty one year oldmale patient with giant bullae misdiagnosed as tensionpneumothorax and underwent to tube thoracostomy. Thedifferential diagnosis of giant bullae and tension pneumothoraxmay be confusing. The therapeutic approaches ofthese two radiologically similar entities differ significantly.Thus proper physical assessment and radiological examinationis crucial in the differential diagnosis and computedtomography examination should be performed before theadjustment of therapy. J Clin Exp Invest 2012; 3(4: 548-551Key words: Tension pneumothorax, giant bullae, computedtomography, tube thoracostomy

  19. Corrosion control in mining technology

    Energy Technology Data Exchange (ETDEWEB)

    Telekesi, J.

    1985-01-01

    An overview of corrosion effects in mining technology and the importance of protection is presented. The most common corrosion processes and effects are summarized and the system and criteria of their avoidance are discussed in detail. Preventive measures are recommended to decrease possible corrosion effects including the selection of corrosion-resistive constructions, to use protective coatings and inhibition techniques and some other protection possibilities where applicable. The organization aspects and the economic impact of corrosion control in mining are discussed.

  20. Corrosion-resistant uranium

    Science.gov (United States)

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  1. Efecto de las Cargas en el Agrietamiento por Corrosión Bajo Tensión

    OpenAIRE

    2006-01-01

    Aborda los aspectos relacionados con la definición de la corrosión bajo tensión como la aceleración del ataque de la corrosión debido a una solicitación mecánica, tratándose de la sustitución de una agresividad aparente soportante por una agresividad específica pequeña o media. Cuando actúa una solicitación mecánica sobre un metal que se halle en un medio corrosivo, puede originarse agrietamiento con posterior rotura. La solicitación mecánica puede ser debida a tensiones externas o bien trata...

  2. Factores de riesgo en el bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Guillermo Díaz Alonso

    Full Text Available Se realizó un estudio retrospectivo de tipo caso control en el área del Policlínico Docente "Luis A. Turcios Lima" del municipio 10 de Octubre durante el período de 1990 a 1993, con el objetivo de identificar el comportamiento del bajo peso al nacer, establecer la existencia y la intensidad de esta entidad con los factores de riesgo seleccionados, e identificar el grado de influencia individual de dichos factores. La muestra quedó conformada por 92 recién nacidos de bajo peso y 468 con normopeso. Las variables estudiadas fueron la edad materna, la valoración ponderal, las complicaciones obstétricas, las enfermedades asociadas con la gestación, el hábito de fumar y el período intergenésico. Se aplicó el test chi-cuadrado, el odds- -ratio y el de riesgo atribuible en los nacimientos expuestos y en la población total. Todas las variables estuvieron asociadas significativamente con el bajo peso al nacer, y fueron identificadas como factores de riesgo con influencia marcada: la edad materna de 35 años o más, la amenaza de parto prematuro, la rotura prematura de membranas, la toxemia y la diabetes mellitus; con efecto moderado, el bajo peso materno, un período intergenésico menor de 1 año, la hipertensión arterial, el asma bronquial, el hábito de fumar, la sepsis urinaria, y con influencia ligera, la edad materna inferior a los 20 años.

  3. Horizon Thermodynamics and Gravitational Tension

    CERN Document Server

    Widom, A; Srivastava, Y N

    2016-01-01

    We consider the thermodynamics of a horizon surface from the viewpoint of the vacuum tension $\\tau =(c^4/4G )$. Numerically, $\\tau \\approx 3.026\\times 10^{43}$ Newton. In order of magnitude, this is the tension that has been proposed for microscopic string models of gravity. However, after decades of hard work on string theory models of gravity, there is no firm scientific evidence that such models of gravity apply empirically. Our purpose is thereby to discuss the gravitational tension in terms of the conventional Einstein general theory of relativity that apparently does explain much and maybe all of presently known experimental gravity data. The central result is that matter on the horizon surface is bound by the entropy-area law by tension in the closely analogous sense that the Wilson action-area law also describes a surface confinement.

  4. CULTIVOS BAJO CUBIERTA EN EL SURESTE DE ESPAÑA

    Directory of Open Access Journals (Sweden)

    Encarnación Gil Meseguer

    2011-01-01

    Full Text Available En España, más de 62.000 ha regadas se cultivan en ambiente controlado, bajo determinadas cubiertas. Dos tercios se localizan en Andalucía, y más de la cuarta parte, en el Sureste de la Península Ibérica. En el espacio surestino, delimitado por la coincidencia de las isolíneas climáticas (isoyeta de los 400 mm anuales e isoterma de 16ºC de TMA y la línea de costa mediterránea entre Almería y Alicante, sobresalen una serie de estructuras con cubiertas de plásticos y mallas para la producción de cultivos intensivos en las comarcas del Levante Almeriense-Bajo Almanzora, Lorca y Valle Guadalentín, Campo de Cartagena-Mar Menor, Meridional de Alicante-Vega Baja, etc. Los avances tecnológicos aplicados al riego y al ciclo natural de la planta, se incorporan al cultivo forzado bajo cubierta, logrando modificar el ciclo de cultivo, con una amplitud en los calendarios para presentar el producto en los momentos de mayor demanda. El interés de esta agricultura intensiva de invernaderos, mallas y acolchados radica en su mayor productividad, empleo y precio final del producto.

  5. Corrosion Inhibitors for Aluminum.

    Science.gov (United States)

    Muller, Bodo

    1995-01-01

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

  6. Análisis dimensional del comportamiento hiperelástico del tubo arterial bajo un estado multiaxial de tensiones

    Directory of Open Access Journals (Sweden)

    Mauricio Barrera

    2016-01-01

    Full Text Available Se aplicó la mecánica de sólidos hiperelásticos al estudio del comportamiento del tubo arterial, ya que es un medio consolidado en la comprensión de fenómenos de interés para los profesionales de la medicina y de la ingeniería biomédica. En el caso del órgano en cuestión, su estudio se realizó mediante el modelado como un recipiente cilíndrico de pared gruesa, donde la función de energía empleada permitió considerar aspectos microestructurales como la anisotropía y la dispersión de fibras de colágeno. En el problema de equilibrio estático en el que se implementa esta caracterización se representaron las capas media y adventicia de la pared arterial. La solución expedita del problema de valores en la frontera resultante es posible gracias a la asunción de un patrón de deformación de simetría axial. Se encontró que el factor de dispersión de fibras y los demás parámetros adimensionales del mismo orden de magnitud tienen el rol dominante en la rigidez radial del tubo arterial. Los resultados se presentan utilizando grupos adimensionales, lo cual facilita la interpretación rápida del efecto de los numerosos parámetros que emergen.

  7. Application of the method of thermo-power in diagnosing fatigue strength and intergrain corrosion

    Directory of Open Access Journals (Sweden)

    Dominjuk T.I

    2009-04-01

    Full Text Available In area of flat defect, predefined a gradient tireless - corrosive tensions, a double electric layer, conditioned the spatial redistribution of electronic closeness, is formed. It shows up a local rejection mikro-thermo-power at use of heating edge of tungsten thermocouple. Test approbation of method is conducted on the deformed chromel.

  8. Modelling reinforcement corrosion in concrete

    DEFF Research Database (Denmark)

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

    2012-01-01

    A physio-chemical model for the simulation of reinforcement corrosion in concrete struc-tures was developed. The model allows for simulation of initiation and subsequent propaga-tion of reinforcement corrosion. Corrosion is assumed to be initiated once a defined critical chloride threshold...... is reached causing the formation of anodic and cathodic regions along the reinforcement. Critical chloride thresholds, randomly distributed along the reinforcement sur-face, link the initiation and propagation phase of reinforcement corrosion. To demonstrate the potential use of the developed model......, a numerical example is pre-sented, that illustrates the formation of corrosion cells as well as propagation of corrosion in a reinforced concrete structure....

  9. Corrosion and Corrosion Control in Light Water Reactors

    Science.gov (United States)

    Gordon, Barry M.

    2013-08-01

    Serious corrosion problems have plagued the light water reactor (LWR) industry for decades. The complex corrosion mechanisms involved and the development of practical engineering solutions for their mitigation will be discussed in this article. After a brief overview of the basic designs of the boiling water reactor (BWR) and pressurized water reactor (PWR), emphasis will be placed on the general corrosion of LWR containments, flow-accelerated corrosion of carbon steel components, intergranular stress corrosion cracking (IGSCC) in BWRs, primary water stress corrosion cracking (PWSCC) in PWRs, and irradiation-assisted stress corrosion cracking (IASCC) in both systems. Finally, the corrosion future of both plants will be discussed as plants extend their period of operation for an additional 20 to 40 years.

  10. Aulas-laboratorios de bajo costo, usando TIC

    Directory of Open Access Journals (Sweden)

    Silvia E. Calderón

    2015-01-01

    Full Text Available En este trabajo se presentan los resultados de una propuesta educativa orientada a promover el desarrollo de un pensamiento critico y un mayor interes por las ciencias experimentales. Con este fin desarrollamos propuestas de proyectos educativos susceptibles de ser destinadas a las aulas y laboratorios de las escuelas secundarias y primeros anos de la universidad, que resaltan los aspectos metodologicos de las ciencias. Aqui, realizamos una compilacion de varios proyectos, que ilustran formas de incorporar las tecnologias de la informacion y la comunicacion (TIC en diversos experimentos de ciencias, muchos de ellos publicados individualmente anteriormente, y que en conjunto se pueden utilizar para implementar un aula-laboratorio de bajo costo. Con TIC hacemos referencia a la convergencia de computadoras, sistemas audiovisuales, Internet, telefonia, y diversos equipos que se integran con algunos de ellos. Los proyectos intentan integrar areas como fisica, matematica, quimica, informatica, arte, etc. y apuntan a que los estudiantes puedan responder a las preguntas: .Como sabemos esto?, .Por que creemos en aquello? Preguntas que ilustran la naturaleza del pensamiento cientifico. Nuestra contribucion mas significativa es haber desarrollado ≪aulas-laboratorios≫ de muy bajo costo, usando TIC. Con el advenimiento de programas como ≪Una Laptop por Nino≫ que se estan implementando en varios paises de Latinoamerica, resulta oportuno utilizar este recurso como base para generar laboratorios de bajo costo, que creemos pueden ser una herramienta util para mejorar el aprendizaje de las ciencias, incentivar vocaciones y contribuir a desarrollar un pensamiento critico, a la par de desarrollar habilidades con el uso de las TIC que pueden ser de utilidad en diversos ambitos academicos y laborales.

  11. Corrosion testing using isotopes

    Science.gov (United States)

    Hohorst, Frederick A.

    1995-12-05

    A method for determining the corrosion behavior of a material with respect to a medium in contact with the material by: implanting a substantially chemically inert gas in a matrix so that corrosion experienced by the material causes the inert gas to enter the medium; placing the medium in contact with the material; and measuring the amount of inert gas which enters the medium. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a body of the material, which body has a surface to be contacted by the medium; and a substantially chemically inert gas implanted into the body to a depth below the surface. A test sample of a material whose resistance to corrosion by a medium is to be tested, composed of: a substrate of material which is easily corroded by the medium, the substrate having a surface; a substantially chemically inert gas implanted into the substrate; and a sheet of the material whose resistance to corrosion is to be tested, the sheet being disposed against the surface of the substrate and having a defined thickness.

  12. Severe Environmental Corrosion Erosion Facility

    Data.gov (United States)

    Federal Laboratory Consortium — NETL’s Severe Environment Corrosion Erosion Facility in Albany, OR, allows researchers to safely examine the performance of materials in highly corrosive or erosive...

  13. Consumidores de bajos ingresos: entrenamiento, atribuciones y expectativas del gerente

    OpenAIRE

    Silvana Dakduk; José Malavé

    2014-01-01

    La teoría de la atribución y los hallazgos acerca de iniciativas de negocio dirigidas a los consumidores de bajos ingresos sugieren que el entrenamiento de los gerentes con respecto a estos consumidores podría influir sobre sus atribuciones y expectativas de éxito en tales iniciativas. Para analizar las relaciones entre estas variables se llevó a cabo un estudio descriptivo correlacional sobre una muestra de 370 estudiantes de gerencia, que se desempeñaban como gerentes medios en organizacion...

  14. HABILIDADES MATEMÁTICAS EN ALUMNOS DE BAJO NIVEL SOCIOCULTURAL

    OpenAIRE

    YOLANDA GUEVARA BENÍTEZ; ÁNGELA HERMOSILLO GARCÍA; ALFREDO LÓPEZ HERNÁNDEZ; ULISES DELGADO SÁNCHEZ; GUSTAVO RENÉ GARCÍA VARGAS; JUAN PABLO RUGERIO TAPIA

    2008-01-01

    La temática abordada es la calidad de la educación básica en México. Con el propósito de dar cuenta del proceso de desarrollo de diversas habilidades matemáticas en alumnos de primer grado de primaria, se realizó un estudio longitudinal en el cual participaron 169 alumnos de estrato sociocultural bajo. Se aplicó un instrumento referido a criterio y basado en análisis de tareas, que permitió analizar los aciertos y errores a lo largo del ciclo escolar 2004-2005. Los resultados indican que los ...

  15. Cobertura en el sudoeste bonaerense en suelos bajo siembra directa

    OpenAIRE

    López, Fernando Manuel; Duval, Matias Ezequiel; Martinez, Juan Manuel; Galantini, Juan Alberto

    2017-01-01

    El manejo bajo siembra directa (SD) se asocia generalmente con altos niveles de residuos de cultivos sobre la superficie del suelo, lo que tiene efectos positivos sobre la fertilidad física y química, la biología del suelo y el control de la erosión. Sin embargo, la ausencia de cobertura puede tener un efecto más negativo en la calidad del suelo en el largo plazo que la labranza convencional. En el presente trabajo se determinó la presencia de residuos en superficie y la cobertura del suelo a...

  16. El Siglo XIX. Bajo el Signo del Romanticismo

    OpenAIRE

    Navascués Palacio, Pedro

    1992-01-01

    Los autores han puesto estas páginas, dedicadas al Arte Español del siglo XIX, bajo el signo del Romanticismo, por entender que bien pudiera ser éste el común denominador de la actividad artística de aquella centuria. Sin duda es el horizonte del sentimiento donde las artes plásticas se encuentran entre sí y, a la vez, coinciden con otras fronteras de la cultura del Ochocientos. Se analiza en esta obra el papel coyuntural y crítico que desempeña el arte del siglo XIX entre el siglo XVIII, en ...

  17. [Epiphytic algae from Bajo Pepito, Isla Mujeres, Quintana Roo, Mexico].

    Science.gov (United States)

    Quan-Young, L I; Díaz-Martín, M A; Espinoza-Avalos, J

    2006-06-01

    A total of 96 epiphytic algae species were identified from Bajo Pepito, Quintana Roo, México. 60.4% (58) belonged to the Rhodophyta, 19.79% (19) to the Phaeophyta, 16.6% (16) to the Chlorophyta and 3.1% (3) to the Cyanophyta; 49 species (50.5%) were found only in one month, while Heterosiphonia crispella was found in all of the sampled months. That species provided the largest contribution to the biomass of epiphytes. During January we registered the greater biommass and richness of epiphytes species, coincidently with high values of host species cover and rainfall.

  18. Multi-physics corrosion modeling for sustainability assessment of steel reinforced high performance fiber reinforced cementitious composites

    DEFF Research Database (Denmark)

    Lepech, M.; Michel, Alexander; Geiker, Mette

    2016-01-01

    Using a newly developed multi-physics transport, corrosion, and cracking model, which models these phenomena as a coupled physiochemical processes, the role of HPFRCC crack control and formation in regulating steel reinforcement corrosion is investigated. This model describes transport of water...... tension-softening cementitious composites. Finally, these results are extended to provide greater insight into the assessment and design of more sustainable steel reinforced HPFRCC structures....

  19. Cosmic Strings with Small Tension

    CERN Document Server

    Halyo, Edi

    2009-01-01

    We describe cosmic F--term strings with exponentially small tension which are D3 branes wrapped on deformed $A_3$ singularities. We show that brane instanton effects which can be calculated after a geometric transition give rise to an exponentially small volume for the node on which the D3 branes wrap leading to a string with small tension. We generalize our description to the case of non--Abelian cosmic strings and argue that these strings are stable against monopole--anti monopole pair creation.

  20. Corrosion-resistant metallic coatings

    OpenAIRE

    F. Presuel-Moreno; M.A. Jakab; N. Tailleart; Goldman, M.; J. R. Scully

    2008-01-01

    We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned) to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic i...

  1. Corrosion-resistant metal surfaces

    Science.gov (United States)

    Sugama, Toshifumi [Wading River, NY

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  2. Plastics for corrosion inhibition

    CERN Document Server

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

    2005-01-01

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

  3. Solving A Corrosion Problem

    Science.gov (United States)

    1979-01-01

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

  4. Thin film corrosion. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Raut, M.K.

    1980-06-01

    Corrosion of chromium/gold (Cr/Au) thin films during photolithography, prebond etching, and cleaning was evaluated. Vapors of chromium etchant, tantalum nitride etchant, and especially gold etchant were found to corrosively attack chromium/gold films. A palladium metal barrier between the gold and chromium layers was found to reduce the corrosion from gold etchant.

  5. Corrosion resistant PEM fuel cell

    Science.gov (United States)

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

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  6. Aplicación del mecanismo de movilidad superficial a la corrosión bajo tensión de materiales H.C.P. en soluciones de yodo

    Directory of Open Access Journals (Sweden)

    Farina, S. B.

    2004-04-01

    Full Text Available Stress corrosion cracking (SCC susceptibility of some h.c.p. metals: titanium, zirconium and one of its alloys, Zircaloy-4, was investigated in iodine-methanol solutions. Slow strain rate tests were carried out until the rupture of the specimens, in some cases interrupted strain rate tests were conducted. SCC was observed in all the systems studied, but preceding crack propagation, intergranular attack was found in all cases, and this intergranular attack was due to anodic dissolution of the grain boundaries. The rate controlling step is the diffusion of iodine to the tip of the advanced crack. It was also demonstrated, that it is necessary to locally disrupt the passive film to induce SCC in these materials and this is done by the chemical effect of the iodine molecules on both, titanium and zirconium oxide film. Once the intergranular attack reaches a certain value, a transition to a transgranular cracking mode occurs. This last step was identified as the “true” SCC process. The surfacemobility SCC mechanism was applied to explain the results obtained.

    Se estudió la susceptibilidad a la corrosión bajo tensión (CBT de materiales hcp: titanio, circonio y Zircaloy-4, en soluciones de yodo en metanol, por medio de la realización de ensayos de tracción a velocidad lenta de deformación hasta rotura de la probeta o interrumpidos antes de que ella ocurra. En todos los sistemas se encontró CBT, pero previo a la propagación de las fisuras se determinó la existencia de ataque intergranular asistido por tensiones, debido a disolución anódica de los bordes de grano. El paso controlante del proceso global es la difusión del yodo complejado con la molécula de metanol al fondo de la fisura durante la propagación. Se demostró que es necesario que se produzca la rotura local de la película pasivante para inducir CBT en estos materiales. Este fenómeno es producido por el efecto químico del yodo sobre los óxidos de titanio y circonio

  7. Consumidores de bajos ingresos: entrenamiento, atribuciones y expectativas del gerente

    Directory of Open Access Journals (Sweden)

    Silvana Dakduk

    2014-01-01

    Full Text Available La teoría de la atribución y los hallazgos acerca de iniciativas de negocio dirigidas a los consumidores de bajos ingresos sugieren que el entrenamiento de los gerentes con respecto a estos consumidores podría influir sobre sus atribuciones y expectativas de éxito en tales iniciativas. Para analizar las relaciones entre estas variables se llevó a cabo un estudio descriptivo correlacional sobre una muestra de 370 estudiantes de gerencia, que se desempeñaban como gerentes medios en organizaciones que atienden a consumidores de bajos ingresos. Los resultados mostraron relaciones entre el entrenamiento y la atribución de características de sociabilidad a estos consumidores, y entre la atribución de sociabilidad y las expectativas de éxito con ofertas tradicionales. La mayoría de los participantes no ha recibido entrenamiento para el trabajo con estos consumidores, lo cual confirma hallazgos referidos a la dificultad para desarrollar ofertas innovadoras: desconocimiento y distanciamiento. Este trabajo contribuye al conocimiento disponible, en empresas e instituciones educativas, para formar personal responsable de desarrollar negocios rentables y adaptados a las necesidades de una población de tanta relevancia.

  8. Bajo materialismo y surrealismo. El debate Bataille-Breton

    Directory of Open Access Journals (Sweden)

    Noelia Denise Dunan

    2015-01-01

    Full Text Available Hacia 1923 Georges Bataille era un joven desconocido que comenzaba a entablar amistades y también enemistades en el núcleo del movimiento surrealista e intelectual de París. Alentado por algunos de aquellos vínculos, lee a Mauss y Durkheim, Nietzsche y Freud y, comienza a delinear un pensamiento que se plasmará en la creación de Documents. Resulta difícil comprender la relevancia de esta revista y la producción batailleana sin referir a sus primeras lecturas y al debate que tempranamente entabló con el máximo exponente del movimiento surrealista, André Breton. Bataille coordinó allí un grupo de disidentes y convirtió la publicación en una máquina contra el surrealismo. El presente artículo desarrolla la formación de Bataille para hacer hincapié en la categoría de bajo materialismo construida en tensión entre el idealismo surrealista y los distintos materialismos. Así puede verse que Documents y el bajo materialismo conjugan las preocupaciones que perseguirá toda su vida.

  9. Perubahan Sosial Pada Komunitas Suku Bajo Di Pesisir Teluk Tomini

    Directory of Open Access Journals (Sweden)

    Muhammad Obie

    2016-06-01

    Full Text Available Abstract: Society and culture of human being always change as an ever –present phenomena in the world. A distinction is sometimes made then between processes of change within the social structure, which serve in part to maintain the structure, and, even the processes itself can be slow or fast through evolusion and revolusion.   One of the factors that quicken the social change process is the government interventions. This study aims at analyzing the social change on the Bajo Tribe community as the impact of various government programs at Tomini bay coastal. This research used strategy of historical sociology. The kinds of data collected were primer and secondary data that were analyzed by using qualitative approac. The result showed that various   government programs at Tomini bay, such as designating conservation area, granting concession license to private sectors through forest concession right (FCR, indefeasible right of use (IRU, and fishing industry at the bay had caused the loss of access of the Bajo tribe community to coastal and marine resources area. Various interventions of government programs had implication on resettlement of the Bajo tribe community, causing the Bajo tribe divided into sea Bajo and land Bajo. The loss of access of the Bajo tribe to coastal and marine resources caused traditional institution weaken which made its philosophy of living in harmony with nature, and  conservation ethics fade away, its local wisdom, and self identity lose, and its social capital destructed.  الملخص: كان المجتمع وحضارته متغيّرين في أيّ كان المجتمع وهذه الحضارة. ويكون الفرق في كون هذا التغيّر. قد تكون عملية التغيّر متمهّلة أو سريعة وقد تكون عن طريق التطوّر والثّورة. وأحد العناصر المسرعة في عملية هذا التغيّر هو تدخّل الحكومة. حاولت هذه

  10. AUTOGENIC THERAPY IN TENSION HEADACHE

    OpenAIRE

    Amruthraj, Brunda; Mishra, H.; Kumaraiah, V.

    1987-01-01

    SUMMARY Ten subjects diagnosed as Psychalgia were taken for study. A multiple baseline design was adapted and clients were subjected to 30 sessions of autogenic training. They were assessed using physiological (EMG and thermal change) and behavioural measures (Visual analogue scale and behavioural symptom checklist). Findings revealed autogenic therapy to be effective in reducing tension headache.

  11. Tension type headaches: a review

    African Journals Online (AJOL)

    23. Epidemiology. A wide variation in the prevalence of tension-type headaches .... intensity tending to be less in the morning, building up after noon, and reducing ... with a change in position or the start of Valsalva-like sneezing. • Associated ...

  12. Abolishing the maximum tension principle

    CERN Document Server

    Dabrowski, Mariusz P

    2015-01-01

    We find the series of example theories for which the relativistic limit of maximum tension $F_{max} = c^2/4G$ represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.

  13. Abolishing the maximum tension principle

    Directory of Open Access Journals (Sweden)

    Mariusz P. Da̧browski

    2015-09-01

    Full Text Available We find the series of example theories for which the relativistic limit of maximum tension Fmax=c4/4G represented by the entropic force can be abolished. Among them the varying constants theories, some generalized entropy models applied both for cosmological and black hole horizons as well as some generalized uncertainty principle models.

  14. CALCULATION OF TENSION FORCE OF BELT CONVEYOR

    Directory of Open Access Journals (Sweden)

    Ismet Ibishi

    2012-12-01

    Full Text Available In this paper is done the explanation on tension fashion of the belt conveyor which is employed in Kosovo Energy Corporation – KEK, for coal transportation to provide electric power plant. The aim of the paper enables to recognize tension forces not to pass with deformation of belt so that this problem will damage the workingprocess. Work principle is based on initial tension and tension during working process. The fact is known that the tension starts from the carriage on the way to tension mechanization, so forces on the rope passing through pulley there has to dominate the friction coefficient. All this process is related to economy of transportationmechanism.

  15. Corrosion protection by anaerobiosis.

    Science.gov (United States)

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

    2001-01-01

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

  16. Smart Coatings for Corrosion Protection

    Science.gov (United States)

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

    2016-01-01

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

  17. Corrosion potential analysis system

    Science.gov (United States)

    Kiefer, Karl F.

    1998-03-01

    Many cities in the northeastern U.S. transport electrical power from place to place via underground cables, which utilize voltages from 68 kv to 348 kv. These cables are placed in seamless steel pipe to protect the conductors. These buried pipe-type-cables (PTCs) are carefully designed and constantly pressurized with transformer oil to prevent any possible contamination. A protective coating placed on the outside diameter of the pipe during manufacture protects the steel pipe from the soil environment. Notwithstanding the protection mechanisms available, the pipes remain vulnerable to electrochemical corrosion processes. If undetected, corrosion can cause the pipes to leak transformer oil into the environment. These leaks can assume serious proportions due to the constant pressure on the inside of the pipe. A need exists for a detection system that can dynamically monitor the corrosive potential on the length of the pipe and dynamically adjust cathodic protection to counter local and global changes in the cathodic environment surrounding the pipes. The northeastern United States contains approximately 1000 miles of this pipe. This milage is critical to the transportation and distribution of power. So critical, that each of the pipe runs has a redundant double running parallel to it. Invocon, Inc. proposed and tested a technically unique and cost effective solution to detect critical corrosion potential and to communicate that information to a central data collection and analysis location. Invocon's solution utilizes the steel of the casing pipe as a communication medium. Each data gathering station on the pipe can act as a relay for information gathered elsewhere on the pipe. These stations must have 'smart' network configuration algorithms that constantly test various communication paths and determine the best and most power efficient route through which information should flow. Each network station also performs data acquisition and analysis tasks that ultimately

  18. La defensa de Hispania en el Bajo Imperio

    Directory of Open Access Journals (Sweden)

    Alberto BALIL

    2009-10-01

    Full Text Available La crisis político-militar-económica del Imperio romano, a mediados del siglo III, d. d. J. C, dejó sus huellas en la organización del Bajo Imperio romano. Uno de estos aspectos es la acentuación de los intereses militares, de los trabajos de fortificación y de la reorganización del ejército. Una reorganización que busca precisamente la creación de un ejército de reserva, un ejército de maniobra y de un ejército dotado de gran movilidad. Un sistema defensivo escalonado en profundidad frente al sistema de cobertura lineal del Alto Imperio.

  19. Factores de riesgo en el bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Guillermo Díaz Alonso

    1995-06-01

    Full Text Available Se realizó un estudio retrospectivo de tipo caso control en el área del Policlínico Docente "Luis A. Turcios Lima" del municipio 10 de Octubre durante el período de 1990 a 1993, con el objetivo de identificar el comportamiento del bajo peso al nacer, establecer la existencia y la intensidad de esta entidad con los factores de riesgo seleccionados, e identificar el grado de influencia individual de dichos factores. La muestra quedó conformada por 92 recién nacidos de bajo peso y 468 con normopeso. Las variables estudiadas fueron la edad materna, la valoración ponderal, las complicaciones obstétricas, las enfermedades asociadas con la gestación, el hábito de fumar y el período intergenésico. Se aplicó el test chi-cuadrado, el odds- -ratio y el de riesgo atribuible en los nacimientos expuestos y en la población total. Todas las variables estuvieron asociadas significativamente con el bajo peso al nacer, y fueron identificadas como factores de riesgo con influencia marcada: la edad materna de 35 años o más, la amenaza de parto prematuro, la rotura prematura de membranas, la toxemia y la diabetes mellitus; con efecto moderado, el bajo peso materno, un período intergenésico menor de 1 año, la hipertensión arterial, el asma bronquial, el hábito de fumar, la sepsis urinaria, y con influencia ligera, la edad materna inferior a los 20 años.A case-control retrospective study was carried out at "Luis A. Turcios Lima" Teaching Polyclinics form 10 de Octubre municipality during the period of 1990-1993, with the aim of identifying the behaviour of low birth weight, establishing the occurrence and intensity of this entity with selected risk factors, and identifying the degree of individual influence of such factors. The sample consisted of 92 low birth weight infants and 468 with normal weight. Variables studied were: maternal age, weight appraisal, and obstetric complications, diseases associated with pregnancy, smoking habit, and the

  20. bajo el bosque en Costa Rica. 1980-2000

    Directory of Open Access Journals (Sweden)

    Rafael Ocampo

    2007-01-01

    Full Text Available La ipecacuana o raicilla, hierba nativa de América, es la única planta medicinal del trópico húmedo de Costa Rica cultivada bajo el bosque. Es cultivada en la región Huetar Norte, limítrofe con Nicaragua; la raíz seca de ipecacuana se ha comercializado en Costa Rica como materia prima para la industria farmacéutica internacional desde principios del siglo XX. De acuerdo con las estadísticas oficiales, las exportaciones de raicilla desde Costa Rica en los últimos 20 años han significado un promedio de 64 t año-1. Este trabajo resume actividades relacionadas con la descripción y cultivo de la planta, así como algunos de los aspectos agroecológicos de su cultivo.

  1. Tensions of Corporate Social Responsibility

    DEFF Research Database (Denmark)

    Strand, Robert

    I engaged with the top management team (TMT) and employees of American Cafes Corporation as an action/intervention researcher in the 20 months immediately following the TMT’s decision to formalize the company’s corporate social responsibility (CSR) activities. This led to the establishment...... CSR agenda is considered, which brings with it a multiplicity of substantively rational ends for which the corporation could pursue. I show the CSR bureaucracy can create a space for reflection in which the multiplicity of substantively rational ends can be considered, negotiated, and selected...... for reflection within the corporation. But I also show tensions can arise from the establishment of the CSR bureaucracy itself. This suggests the CSR bureaucracy itself resides in a tension....

  2. Introducing surface tension to spacetime

    Science.gov (United States)

    Perko, H. A.

    2017-05-01

    Concepts from physical chemistry of surfaces and surface tension are applied to spacetime. More specifically, spacetime is modeled as a spatial fluid continuum bound together by a multi-dimensional membrane of time. A metric tensor that relates empty flat spacetime to energetic curved spacetime is found. Equations of motion for an infinitesimal unit of spacetime are derived. The equation of motion in a time-like direction is a Klein-Gordon type equation. The equations of motion in space-like directions take the form of Schrodinger’s equation where Plank’s constant is related to membrane elastic modulus. Although much work remains, it is suggested that the spacetime surface tension may serve as a mechanical model for many phenomena in quantum mechanics and atomic particle physics.

  3. Sistema radical en genotipos de papa, bajo condiciones de invernadero

    Directory of Open Access Journals (Sweden)

    S. Cortez

    2000-01-01

    Full Text Available Sistema radical en genotipos de papa, bajo condiciones de invernadero. El presente trabajo tuvo como objetivos estudiar la variabilidad del crecimiento y distribución del sistema radical en 10 clones comerciales y experimentales de papa, e identificar los mejores materiales en diferentes perfiles de suelo. Se utilizó un diseño completamente al azar con dos repeticiones, bajo condiciones de invernadero en la Universidad Autónoma Agraria Antonio Narro., Saltillo, México. Para la evaluación del sistema radical se utilizaron bolsas de polietileno de 90 cm de largo y 30 cm de diámetro. Se aplicaron riegos restringidos para obtener mejor desarrollo radical. La parcela experimental fue una bolsa con dos plantas. Después de la floración y con un crecimiento de 125 días, se cortó el vástago. El suelo de cada bolsa que contenía las raíces fue seccionado en cuatro segmentos. Estas raíces, se recuperaron y luego se lavaron. El vástago y las raíces se secaron al horno a 70 °C durante 48 horas y se obtuvo peso seco. El análisis de varianza mostró diferencias altamente significativas entre variedades, para peso seco de sistema radical en los cuatro perfiles estudiados 0-20, 20-40, 40-60, 60-80 cm y para el perfil total (0-80 cm. Las variedades Boer, Russet Burbank y Utatlan fueron sobresalientes en la producción total de raíces. Las variedades Boer, Russet Burbank, Atlantic y Gigant mostraron mayor cantidad de raíces en el perfil de 60-80 cm y produjeron un buen patrón de crecimiento radical en diferentes perfiles

  4. Tensile Behavior of Alloy 718 in Hot Corrosive Environment

    Science.gov (United States)

    Mahobia, G. S.; Paulose, Neeta; Mannan, S. L.; Chattopadhyay, K.; Santhi Srinivas, N. C.; Singh, Vakil

    2013-12-01

    Nickel-iron-based alloy 718 was thermally exposed in peak-aged condition at 550 and 650 °C, from 5 to 100 h, with and without salt coatings and was tested in tension at room temperature and elevated temperatures. Standard tensile specimens were coated with three different salts (in wt.%): NaCl(100), Na2SO4 + NaCl (75/25), and Na2SO4 + NaCl + V2O5 (90/5/5). Exposure of salt-coated specimens at 550 and 650 °C revealed formation of scales and corrosion pits. Tensile deformation resulted in cracking of the surface oxide/corrosion scale. The uncoated specimens showed formation of oxide scales on the surface, without any cracking whereas the salt-coated specimens showed surface cracking and pitting at some places. However, tensile properties were not degraded due to salt coatings.

  5. Frequency dependence of fatigue and corrosion fatigue crack growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Marvasti, Mohammad Hassan; Chen, Weixing [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB (Canada); Kania, Richard; Worthingham, Robert [TransCanada Pipelines Limited, Calgary, AB (Canada); Van Boven, Gregory [Spectra Energy Transmission Limited, Vancouver, BC (Canada)

    2010-07-01

    It was in the mid-1980s that stress corrosion cracking (SCC) was first found in near-neutral pH conditions on the TransCanada pipeline system. Since then, there have been many reports of pipeline cracking in Canada in these conditions. The huge quantity of pipelines in Canada and the number of failures have brought great interest in investigation of this cracking. A study was conducted on one X52 pipeline steel. It used compact tension specimens for corrosion fatigue and fatigue tests in air. The following conclusions were drawn: 1) crack growth in near-neutral pH conditions can be explained by a factor, which reflects the combined action of the mechanical driving force and the hydrogen effects; 2) mechanical dormancy can be common when oil and gas pipelines are in operation; 3) hydrogen is a determining factor of crack growth when pipeline steels are exposed to near-neutral pH conditions.

  6. Robust Tensioned Kevlar Suspension Design

    Science.gov (United States)

    Young, Joseph B.; Naylor, Bret J.; Holmes, Warren A.

    2012-01-01

    One common but challenging problem in cryogenic engineering is to produce a mount that has excellent thermal isolation but is also rigid. Such mounts can be achieved by suspending the load from a network of fibers or strings held in tension. Kevlar fibers are often used for this purpose owing to their high strength and low thermal conductivity. A suite of compact design elements has been developed to improve the reliability of suspension systems made of Kevlar.

  7. Consideration on corrosion fatigue crack life assessment; Fushoku hiro kiretsu hassei jumyo hyoka ni kansuru ichikosatsu

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, H.; Yamamoto, M.; Saito, T. [Hiroshima University, Hiroshima (Japan). Faculty of Engineering; Morita, K. [Mitsubishi Heavy Industries, Ltd., Tokyo (Japan)

    1996-10-01

    Discussions were given on corrosion fatigue crack life by using corrosion fatigue crack initiation test and analysis. The test used 13Cr-based stainless steel as a test material, and aquamarine at 60{degree}C as a corrosion environment. The fatigue test was performed under a tension loading condition with a stress ratio of 0.1 and an iterative velocity of 1.7 Hz by using a 10-tonf fatigue testing machine. In the corrosion fatigue crack initiation test, a pit has been generated on a boundary of an exposed part and a painted part for masking, hence direct observation was impossible on pit growth behavior. Therefore, an intrinsic crack model was introduced from pit dimensions as observed from a fracture face, and analysis was made on corrosion fatigue crack growth by using the linear fracture dynamics, wherein clarification was made on a phenomenon occurring after the crack growth passes the pit growth until the test piece is fractured. A proposal was made to define the time when fatigue crack initiates and grows from the bottom of a pit as a result of surpassing the growth of corrosion pit as the corrosion fatigue crack life. 4 refs., 7 figs., 1 tab.

  8. Scanning reference electrode techniques in localized corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Isaacs, H.S.; Vyas, B.

    1979-04-01

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

  9. Corrosion Evaluation and Corrosion Control of Steam Generators

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-15

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

  10. Corrosion-resistant metallic coatings

    Directory of Open Access Journals (Sweden)

    F. Presuel-Moreno

    2008-10-01

    Full Text Available We describe recent computational and experimental studies on the corrosion properties of metallic coatings that can be tailored (tuned to deliver up to three corrosion-inhibiting functions to an underlying substrate. Attributes are tuned by a selection of alloy compositions and nanostructures, ideally in alloy systems that offer flexibility of choice to optimize the corrosion-resisting properties. An amorphous Al-based coating is tuned for corrosion protection by on-demand release of ionic inhibitors to protect defects in the coating, by formation of an optimized barrier to local corrosion in Cl− containing environments, as well as by sacrificial cathodic prevention. Further progress in this field could lead to the design of the next generation of adaptive or tunable coatings that inhibit corrosion of underlying substrates.

  11. Automated methods of corrosion measurement

    DEFF Research Database (Denmark)

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

    1997-01-01

    Measurements of corrosion rates and other parameters connected with corrosion processes are important, first as indicators of the corrosion resistance of metallic materials and second because such measurements are based on general and fundamental physical, chemical, and electrochemical relations....... Hence improvements and innovations in methods applied in corrosion research are likeliy to benefit basic disciplines as well. A method for corrosion measurements can only provide reliable data if the beckground of the method is fully understood. Failure of a method to give correct data indicates a need...... to revise assumptions regarding the basis of the method, which sometimes leads to the discovery of as-yet unnoticed phenomena. The present selection of automated methods for corrosion measurements is not motivated simply by the fact that a certain measurement can be performed automatically. Automation...

  12. Corrosion inhibitors from expired drugs.

    Science.gov (United States)

    Vaszilcsin, Nicolae; Ordodi, Valentin; Borza, Alexandra

    2012-07-15

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

  13. Automated methods of corrosion measurement

    DEFF Research Database (Denmark)

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

    1997-01-01

    Measurements of corrosion rates and other parameters connected with corrosion processes are important, first as indicators of the corrosion resistance of metallic materials and second because such measurements are based on general and fundamental physical, chemical, and electrochemical relations....... Hence improvements and innovations in methods applied in corrosion research are likeliy to benefit basic disciplines as well. A method for corrosion measurements can only provide reliable data if the beckground of the method is fully understood. Failure of a method to give correct data indicates a need...... to revise assumptions regarding the basis of the method, which sometimes leads to the discovery of as-yet unnoticed phenomena. The present selection of automated methods for corrosion measurements is not motivated simply by the fact that a certain measurement can be performed automatically. Automation...

  14. Nuclear corrosion science and engineering

    CERN Document Server

    2012-01-01

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

  15. Microbiologically Influenced Corrosion

    Science.gov (United States)

    2009-01-01

    in each dimen- sion than bacteria and archaea. Fungi are eukaryotic organisms. Yeasts , molds, and mushrooms are examples of fungi. The majority of...occurs widely in natural waters and can be carried out by a variety of organisms including bacteria, yeast , and fungi (42). Ghiorse (43) prepared a...and its alloys is due to an aluminum oxide passive film. Anodizing produces thicker insulating films and better corrosion resistance. The natural

  16. Corrosion resistant coating

    Science.gov (United States)

    Wrobleski, Debra A.; Benicewicz, Brian C.; Thompson, Karen G.; Bryan, Coleman J.

    1997-01-01

    A method of protecting a metal substrate from corrosion including coating a metal substrate of, e.g., steel, iron or aluminum, with a conductive polymer layer of, e.g., polyaniline, coating upon said metal substrate, and coating the conductive polymer-coated metal substrate with a layer of a topcoat upon the conductive polymer coating layer, is provided, together with the resultant coated article from said method.

  17. CORROSION PROTECTION OF ALUMINUM

    Science.gov (United States)

    Dalrymple, R.S.; Nelson, W.B.

    1963-07-01

    Treatment of aluminum-base metal surfaces in an autoclave with an aqueous chromic acid solution of 0.5 to 3% by weight and of pH below 2 for 20 to 50 hrs at 160 to 180 deg C produces an extremely corrosion-resistant aluminum oxidechromium film on the surface. A chromic acid concentration of 1 to 2% and a pH of about 1 are preferred. (D.C.W.)

  18. Corrosion of bio implants

    Indian Academy of Sciences (India)

    U Kamachi Mudali; T M Sridhar; Baldev Raj

    2003-06-01

    Chemical stability, mechanical behaviour and biocompatibility in body fluids and tissues are the basic requirements for successful application of implant materials in bone fractures and replacements. Corrosion is one of the major processes affecting the life and service of orthopaedic devices made of metals and alloys used as implants in the body. Among the metals and alloys known, stainless steels (SS), Co–Cr alloys and titanium and its alloys are the most widely used for the making of biodevices for extended life in human body. Incidences of failure of stainless steel implant devices reveal the occurrence of significant localised corroding viz., pitting and crevice corrosion. Titanium forms a stable TiO2 film which can release titanium particles under wear into the body environment. To reduce corrosion and achieve better biocompatibility, bulk alloying of stainless steels with titanium and nitrogen, surface alloying by ion implantation of stainless steels and titanium and its alloys, and surface modification of stainless steel with bioceramic coatings are considered potential methods for improving the performance of orthopaedic devices. This review discusses these issues in depth and examines emerging directions.

  19. Corrosion in supercritical fluids

    Energy Technology Data Exchange (ETDEWEB)

    Propp, W.A.; Carleson, T.E.; Wai, Chen M.; Taylor, P.R.; Daehling, K.W.; Huang, Shaoping; Abdel-Latif, M.

    1996-05-01

    Integrated studies were carried out in the areas of corrosion, thermodynamic modeling, and electrochemistry under pressure and temperature conditions appropriate for potential applications of supercritical fluid (SCF) extractive metallurgy. Carbon dioxide and water were the primary fluids studied. Modifiers were used in some tests; these consisted of 1 wt% water and 10 wt% methanol for carbon dioxide and of sulfuric acid, sodium sulfate, ammonium sulfate, and ammonium nitrate at concentrations ranging from 0.00517 to 0.010 M for the aqueous fluids. The materials studied were Types 304 and 316 (UNS S30400 and S31600) stainless steel, iron, and AISI-SAE 1080 (UNS G10800) carbon steel. The thermodynamic modeling consisted of development of a personal computer-based program for generating Pourbaix diagrams at supercritical conditions in aqueous systems. As part of the model, a general method for extrapolating entropies and related thermodynamic properties from ambient to SCF conditions was developed. The experimental work was used as a tool to evaluate the predictions of the model for these systems. The model predicted a general loss of passivation in iron-based alloys at SCF conditions that was consistent with experimentally measured corrosion rates and open circuit potentials. For carbon-dioxide-based SCFs, measured corrosion rates were low, indicating that carbon steel would be suitable for use with unmodified carbon dioxide, while Type 304 stainless steel would be suitable for use with water or methanol as modifiers.

  20. Corrosion detection by induction

    Science.gov (United States)

    Roddenberry, Joshua L.

    Bridges in Florida are exposed to high amounts of humidity due to the state's geography. This excess moisture results in a high incidence of corrosion on the bridge's steel support cables. Also, the inclusion of ineffective waterproofing has resulted in additional corrosion. As this corrosion increases, the steel cables, responsible for maintaining bridge integrity, deteriorate and eventually break. If enough of these cables break, the bridge will experience a catastrophic failure resulting in collapse. Repairing and replacing these cables is very expensive and only increases with further damage. As each of the cables is steel, they have strong conductive properties. By inducing a current along each group of cables and measuring its dissipation over distance, a picture of structural integrity can be determined. The purpose of this thesis is to prove the effectiveness of using electromagnetic techniques to determine cable integrity. By comparing known conductive values (determined in a lab setting) to actual bridge values, the tester will be able to determine the location and severity of any damage, if present.

  1. Corrosion Monitors for Embedded Evaluation

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-05-01

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

  2. Automated Methods of Corrosion Measurements

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    1997-01-01

    electrochemical measurements as well as elemental analysis look very promising for elucidating corrosion reaction mechanisms. The study of initial surface reactions at the atomic or submicron level is becoming an important field of research in the understanding of corrosion processes. At present, mainly two...... scanning microscope techniques are employed investigating corrosion processes, and usually in situ: in situ scanning tunneling microscopy (in situ STM) and in situ scanning force microscopy (in situ AFM). It is these techniques to which attention is directed here....

  3. Panel report on corrosion in energy systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    Corrosion problems in high-temperature (non aqueous) energy systems, corrosion in aqueous energy systems and institutional problems inhibiting the development of corrosion science and engineering are discussed. (FS)

  4. Panel report on corrosion in energy systems

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-06-01

    Corrosion problems in high-temperature (non aqueous) energy systems, corrosion in aqueous energy systems and institutional problems inhibiting the development of corrosion science and engineering are discussed. (FS)

  5. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....

  6. Evaluation of steel corrosion by numerical analysis

    OpenAIRE

    Kawahigashi, Tatsuo

    2017-01-01

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

  7. [Basic family health program in Magdalena Medio y Bajo].

    Science.gov (United States)

    Murad, R

    1992-12-01

    The Program of Information, Education, and Services for Basic Family Health Care in Magdalena Medio and Bajo was designed to increase knowledge and use of contraception and to improve basic health practices and nutrition in the region, which includes municipios belonging to 9 different departments and a total population of 1,720,000. Poverty levels in the area are high. During the 1st year of the project, which was underway from February 1988-May 1991, home visits were made to inform each family about basic family health, to weigh and measure children under 5 not receiving health care elsewhere, and to refer families to the nearest health services. Talks were presented to small groups on family planning, intestinal parasites, sexually transmitted diseases, nutrition, vaccination, cancer prevention, malaria, acute diarrhea, and acute respiratory infection. Community workshops were presented in the 2nd year. Community distribution posts were created for contraceptive and other health product distribution. Information and communication materials from PROFAMILIA were used, and other materials were specially designed for the project by the Foundation for Development of Health Education in Colombia. PROFAMILIA's system of service statistics was used for quantitative evaluation of the information and education activities and sales of contraceptives, antiparasitics, and oral rehydration packets of each instructor. In the 3 years of the program, 89.086 cycles of pills, 398,772 condoms, 29,080 vaginal tablets, 209.791 antiparasitics, and 49,305 oral rehydration packets were sold. 9295 talks were presented to 143,227 residents of the region. 22,000 children were enrolled in the growth monitoring program, and almost 40,000 women were referred for prenatal care and cytology. The instructors gave 900 talks to distributors of contraceptives, antiparasitics, and oral rehydration packets. Surveys of women aged 15-49 residing in the municipios covered by the project were conducted

  8. Axelrod's Model with Surface Tension

    CERN Document Server

    Pace, Bruno

    2012-01-01

    In this work we propose a subtle change in Axelrod's model for the dissemination of culture. The mechanism consists of excluding non-interacting neighbours from the set of neighbours out of which an agent is drawn for potential cultural interactions. Although the alteration proposed does not alter topologically the configuration space, it yields significant qualitative changes, specifically the emergence of surface tension, driving the system in some cases to metastable states. The transient behaviour is considerably richer, and cultural regions have become stable leading to the formation of different spatio-temporal structures. A new metastable "glassy" phase emerges between the globalised phase and the polarised, multicultural phase.

  9. Archaeological analogs and corrosion; Analogues archeologiques et corrosion

    Energy Technology Data Exchange (ETDEWEB)

    David, D

    2008-07-01

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

  10. Mitigation of Corrosion on Magnesium Alloy by Predesigned Surface Corrosion

    Science.gov (United States)

    Zhang, Xuming; Wu, Guosong; Peng, Xiang; Li, Limin; Feng, Hongqing; Gao, Biao; Huo, Kaifu; Chu, Paul K.

    2015-11-01

    Rapid corrosion of magnesium alloys is undesirable in structural and biomedical applications and a general way to control corrosion is to form a surface barrier layer isolating the bulk materials from the external environment. Herein, based on the insights gained from the anticorrosion behavior of corrosion products, a special way to mitigate aqueous corrosion is described. The concept is based on pre-corrosion by a hydrothermal treatment of Al-enriched Mg alloys in water. A uniform surface composed of an inner compact layer and top Mg-Al layered double hydroxide (LDH) microsheet is produced on a large area using a one-step process and excellent corrosion resistance is achieved in saline solutions. Moreover, inspired by the super-hydrophobic phenomenon in nature such as the lotus leaves effect, the orientation of the top microsheet layer is tailored by adjusting the hydrothermal temperature, time, and pH to produce a water-repellent surface after modification with fluorinated silane. As a result of the trapped air pockets in the microstructure, the super-hydrophobic surface with the Cassie state shows better corrosion resistance in the immersion tests. The results reveal an economical and environmentally friendly means to control and use the pre-corrosion products on magnesium alloys.

  11. ¿Aerolíneas de bajo costo en colombia?

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Mantilla

    2003-11-01

    Full Text Available Con la apertura del mercado en Colombia, la competencia entre aerolíneas se agudizó ante la entrada de nuevos operadores y la flexibilización de tarifas como estrategia para la captación de una mayor demanda. Las ventajas competitivas de cada aerolínea fueron el punto clave para la disputa del mercado y todas ellas trabajan hoy en fórmulas que les permitan maximizar beneficios y minimizar costos, enfrentando así la crisis que vive la industria, debido a los acontecimientos del 11 de septiembre de 2001. Puede decirse que los grandes esfuerzos se hacen en los departamentos comerciales, pues debido al auge de las tecnologías y al uso del internet, tanto empresas de transporte aéreo como agentes turísticos deben enfrentar el problema de la competencia de precios. Sin embargo, esto les ofrece a las aerolíneas la oportunidad de comercializar sus servicios a "bajo costo", esquema que ha resultado favorable para empresas y clientes.

  12. Update on normal tension glaucoma

    Directory of Open Access Journals (Sweden)

    Jyotiranjan Mallick

    2016-01-01

    Full Text Available Normal tension glaucoma (NTG is labelled when typical glaucomatous disc changes, visual field defects and open anterior chamber angles are associated with intraocular pressure (IOP constantly below 21 mmHg. Chronic low vascular perfusion, Raynaud's phenomenon, migraine, nocturnal systemic hypotension and over-treated systemic hypertension are the main causes of normal tension glaucoma. Goldmann applanation tonometry, gonioscopy, slit lamp biomicroscopy, optical coherence tomography and visual field analysis are the main tools of investigation for the diagnosis of NTG. Management follows the same principles of treatment for other chronic glaucomas: To reduce IOP by a substantial amount, sufficient to prevent disabling visual loss. Treatment is generally aimed to lower IOP by 30% from pre-existing levels to 12-14 mmHg. Betaxolol, brimonidine, prostaglandin analogues, trabeculectomy (in refractory cases, systemic calcium channel blockers (such as nifedipine and 24-hour monitoring of blood pressure are considered in the management of NTG. The present review summarises risk factors, causes, pathogenesis, diagnosis and management of NTG.

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

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon

    2004-10-01

    The waste package design for the License Application is a double-wall waste package underneath a protective drip shield (BSC 2004 [DIRS 168489]; BSC 2004 [DIRS 169480]). The purpose and scope of this model report is to document models for general and localized corrosion of the waste package outer barrier (WPOB) to be used in evaluating waste package performance. The WPOB is constructed of Alloy 22 (UNS N06022), a highly corrosion-resistant nickel-based alloy. The inner vessel of the waste package is constructed of Stainless Steel Type 316 (UNS S31600). Before it fails, the Alloy 22 WPOB protects the Stainless Steel Type 316 inner vessel from exposure to the external environment and any significant degradation. The Stainless Steel Type 316 inner vessel provides structural stability to the thinner Alloy 22 WPOB. Although the waste package inner vessel would also provide some performance for waste containment and potentially decrease the rate of radionuclide transport after WPOB breach before it fails, the potential performance of the inner vessel is far less than that of the more corrosion-resistant Alloy 22 WPOB. For this reason, the corrosion performance of the waste package inner vessel is conservatively ignored in this report and the total system performance assessment for the license application (TSPA-LA). Treatment of seismic and igneous events and their consequences on waste package outer barrier performance are not specifically discussed in this report, although the general and localized corrosion models developed in this report are suitable for use in these scenarios. The localized corrosion processes considered in this report are pitting corrosion and crevice corrosion. Stress corrosion cracking is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]).

  14. DPC materials and corrosion environments.

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-01

    After an exposition of the materials used in DPCs and the factors controlling material corrosion in disposal environments, a survey is given of the corrosion rates, mechanisms, and products for commonly used stainless steels. Research needs are then identified for predicting stability of DPC materials in disposal environments. Stainless steel corrosion rates may be low enough to sustain DPC basket structural integrity for performance periods of as long as 10,000 years, especially in reducing conditions. Uncertainties include basket component design, disposal environment conditions, and the in-package chemical environment including any localized effects from radiolysis. Prospective disposal overpack materials exist for most disposal environments, including both corrosion allowance and corrosion resistant materials. Whereas the behavior of corrosion allowance materials is understood for a wide range of corrosion environments, demonstrating corrosion resistance could be more technically challenging and require environment-specific testing. A preliminary screening of the existing inventory of DPCs and other types of canisters is described, according to the type of closure, whether they can be readily transported, and what types of materials are used in basket construction.

  15. Agricultural Polymers as Corrosion Inhibitors

    Science.gov (United States)

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

  16. INHIBITION OF CORROSION

    Science.gov (United States)

    Atherton, J.E. Jr.; Gurinsky, D.H.

    1958-06-24

    A method is described for preventing corrosion of metallic container materials by a high-temperature liquid bismuth flowing therein. The method comprises fabricating the containment means from a steel which contains between 2 and 12% chromium, between 0.5 and 1.5% of either molybdenum and silicon, and a minimum of nickel and manganese, and maintaining zirconium dissolved in the liquid bismuth at a concentration between 50 parts per million and its saturation value at the lowest temperature in the system.

  17. Surface tension profiles in vertical soap films

    CERN Document Server

    Adami, N

    2013-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed introducing deformable elastic objets in the films. The shape adopted by those objects set in the film can be related to the surface tension value at a given vertical position by numerical solving of adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position in the soap film can be reproduced by simple modeling taking into account film thickness measurements.

  18. On Surface Tension for Compact Stars

    Indian Academy of Sciences (India)

    R. Sharma; S. D. Maharaj

    2007-06-01

    In an earlier analysis it was demonstrated that general relativity gives higher values of surface tension in strange stars with quark matter than neutron stars. We generate the modified Tolman–Oppenheimer–Volkoff equation to incorporate anisotropic matter and use this to show that pressure anisotropy provides for a wide range of behaviour in the surface tension than is the case with isotropic pressures. In particular, it is possible that anisotropy drastically decreases the value of the surface tension.

  19. Fatigue and Corrosion in Metals

    CERN Document Server

    Milella, Pietro Paolo

    2013-01-01

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

  20. HILBERTIAN APPROACH FOR UNIVARIATE SPLINE WITH TENSION

    Institute of Scientific and Technical Information of China (English)

    A.Bouhamidi

    2001-01-01

    In this work,a new approach is proposed for constructing splines with tension.The basic idea is in the use of distributions theory,which allows us to define suitable Hilbert spaces in which the tension spline minimizes some energy functional.Classical orthogonal conditions and characterizations of the spline in terms of a fundamental solution of a differential operator are provided.An explicit representation of the tension spline is given.The tension spline can be computed by solving a linear system.Some numerical examples are given to illustrate this approach.

  1. Surface Tension Calculation of Undercooled Alloys

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the Butler equation and extrapolated thermodynamic data of undercooled alloys from those of liquid stable alloys, a method for surface tension calculation of undercooled alloys is proposed. The surface tensions of liquid stable and undercooled Ni-Cu (xNi=0.42) and Ni-Fe (xNi=0.3 and 0.7) alloys are calculated using STCBE (Surface Tension Calculation based on Butler Equation) program. The agreement between calculated values and experimental data is good enough, and the temperature dependence of the surface tension can be reasonable down to 150-200 K under the liquid temperature of the alloys.

  2. IN DRIFT CORROSION PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    D.M. Jolley

    1999-12-02

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

  3. [Tension pneumomediastinum and tension pneumothorax following tracheal perforation during cardiopulmonary resuscitation].

    Science.gov (United States)

    Buschmann, C T; Tsokos, M; Kurz, S D; Kleber, C

    2015-07-01

    Tension pneumothorax can occur at any time during cardiopulmonary resuscitation (CPR) with external cardiac massage and invasive ventilation either from primary or iatrogenic rib fractures with concomitant pleural or parenchymal injury. Airway injury can also cause tension pneumothorax during CPR. This article presents the case of a 41-year-old woman who suffered cardiopulmonary arrest after undergoing elective mandibular surgery. During CPR the upper airway could not be secured by orotracheal intubation due to massive craniofacial soft tissue swelling. A surgical airway was established with obviously unrecognized iatrogenic tracheal perforation and subsequent development of tension pneumomediastinum and tension pneumothorax during ventilation. Neither the tension pneumomediastinum nor the tension pneumothorax were decompressed and accordingly resuscitation efforts remained unsuccessful. This case illustrates the need for a structured approach to resuscitate patients with ventilation problems regarding decompression of tension pneumomediastinum and/or tension pneumothorax during CPR.

  4. The Plastic Tension Field Method

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    . The emphasis is attached to the presentation of a design method based on the diagonal tension field theory. Also, how to determine the load-carrying capacity of a given steel plate girder with transverse web stiffeners, is briefly presented. The load-carrying capacity may be predicted by applying both...... method. The method is based on the theory of plasticity and is analogous to the so-called diagonal compression field method developed for reinforced concrete beams with transverse stirrups, which is adopted in the common European concrete code (Eurocode 2). Many other theories have been developed......, but the method presented differs from these theories by incorporating the strength of the transverse stiffeners and by the assumption that the tensile bands may pass the transverse stiffeners, which often is observed in tests. Other methods have only dealt with a single web field between two stiffeners...

  5. Capital intelectual bajo el modelo de e-commerce

    Directory of Open Access Journals (Sweden)

    Gladys Rodríguez

    2009-09-01

    Full Text Available Hoy el mundo está cambiando de una economía basada en el acero, automóviles y carreteras hacia una nueva economía construida con base en silicio, computadoras y redes. Esta revolución tecnológica no se limita a modificar los equipos, los productos, las trayectorias tecnológicas y el modelo organizativo. Sino, como en todo cambio de paradigma hay un proceso de desmantelamiento de lo establecido y la construcción de un nuevo conjunto de principios. Hoy ese nuevo paradigma se fundamenta en el conocimiento, la pericia y sobre todo el talento del hombre. Por tanto, el objetivo principal es describir la importancia que tiene el capital intelectual en las organizaciones de e-commerce. La metodología empleada consistió en una revisión teórica con base a la literatura especializada de autores tales como: Edvinsson y Malone (1998, Brooking (1997, Luz Clara (2001, Merino (2004 y Añez (2005: orientándose hacia el capital intelectual bajo el esquema de negocios de organizaciones de e-commerce. Entre los resultados se destacan dos propuestas: una que describe el proceso de transformación de un negocio tradicional a un negocio de e-commerce sobre la base del capital intelectual; la otra, referida a indicar estrategias gerenciales que apuntan a identificar y evaluar la relación del capital intelectual en cuanto a las innovaciones/ respuestas a los cambios exigidos por el proceso de globalización en el marco de organizaciones de e-commerce.

  6. Ley marco de aseguramiento universal en salud, bajo la lupa

    Directory of Open Access Journals (Sweden)

    Leoncio Díaz

    2009-04-01

    Full Text Available La Ley Marco de Aseguramiento Universal en Salud, concebida en el marco del modelo neoliberal conservador, excluyente y polarizante, fue aprobada en circunstancias en la que persisten grandes contrastes entre sistemas de salud. Por un lado, los países que mantienen subsistemas inconexos y privatizados y, por otro, los que unificados y bajo la responsabilidad del Estado, garantizan a todos el acceso integral, gratuito y de calidad a los servicios de salud. En América y el Caribe, existen países cuyos pobladores carecen de derechos y posibilidades, evidenciando las profundas inequidades que mantienen en exclusión a la mayoría pobre y de extrema pobreza, entre ellos, el Perú muestra indicadores de salud que aún se mantienen en cifras alarmantes y por debajo de los que presentan otras realidades en el mundo. En las últimas tres décadas hubo ensayos frustros de reformas, como la integración funcional del Ministerio de Salud con el Instituto Peruano de Seguridad Social, o el Sistema Nacional Coordinado y Descentralizado en Salud. Actualmente se formula la Ley Marco de Aseguramiento Universal, que mantiene los actuales subsistemas sin variación alguna y con sus propias autonomías, ensayando pilotos, estableciendo planes parciales, implementándola de manera progresiva, priorizando la privatización y debilitando la función rectora del Ministerio de Salud, al crear una superintendencia omnipotente, lo cual continuará permitiendo la exclusión social de más de 9 millones de peruanos. Existe, por tanto, la necesidad de plantear la unificación de los subsistemas, para construir un Sistema Único de Salud, capaz de otorgar salud plena, integral, de calidad y sin costo alguno al 100% de ciudadanos.

  7. Comportamiento del concreto con bajos porcentajes de ceniza volante (termopaipa IV) y agua constante

    National Research Council Canada - National Science Library

    Luz Elena Santaella Valencia; Rodrigo Salamanca Correa

    2004-01-01

    Este artículo se realiza con base en el trabajo de grado titulado Influencia de la ceniza volante procedente de Termopaipa IV adicionada en bajos porcentajes al concreto desarrollada por los estudiantes Milena Puerta...

  8. Estres materno y configuracion familiar: estudio comparativo en familias chilenas monoparentales y nucleares de bajos ingresos

    National Research Council Canada - National Science Library

    Olhaberry, Marcia; Farras, Chamarrita

    2012-01-01

    .... Se estudian los niveles de estres materno en familias chilenas nucleares y monoparentales de NSE bajo, considerando el estres en distintas dimensiones, asociado al rol materno, a la interaccion madre...

  9. Corrosion Prevention and Control Applications Guide

    Science.gov (United States)

    1987-03-31

    Money, Manpower Called Keys to Progress, Aviation Week & Space Technology, October 6, 1980. 12. Reboul , M. C., Galvanic Corrosion of Aluminum, National...PA, April 1980. 25. Reboul , M.C., Galvanic Corrosion of Aluminum, National Association of Corrosion Engineers, Corrosion, V. 35#9, September 1979. 146

  10. Investigation on Atmospheric Corrosiveness in Hainan Province

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    According to the results of four-year exposure tests for carbon steel samples in Hainan province, the influences of meteorological factors and Cl- on atmospheric corrosion were investigated. The feature of atmospheric corrosion in this area was summarized. A corrosive map for the area was drawn. The corrosion products on carbon steel at some typical places were analyzed by XRD and XPS.

  11. Recognition and Analysis of Corrosion Failure Mechanisms

    Directory of Open Access Journals (Sweden)

    Steven Suess

    2006-02-01

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

  12. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

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

    2011-01-01

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

  13. Fatigue of Clip connectors for offshore drilling risers under biaxial tension

    Directory of Open Access Journals (Sweden)

    Gaur Vidit

    2014-06-01

    Full Text Available Drilling riser connectors designed by IFPEN undergo cyclic in-phase biaxial tension in their critical area. This type of loading was reproduced on steel tubular specimens loaded in cyclic tension and internal pressure. The fatigue lives were substantially reduced when the load biaxiality was increased from 0 to 0.4 and then further to 1, which was not captured by existing fatigue criteria. A deeper investigation is thus in progress. Emphasis is laid on the separate evaluation of mean stress and biaxiality effects, often treated in the same way in existing criteria. The influence of load biaxiality on the resistance of the steel to fatigue-corrosion in seawater will also be investigated.

  14. The Impact of Corrosion on the Mechanical Behavior of Welded Splices of Reinforcing Steel S400 and B500c

    Science.gov (United States)

    Apostolopoulos, Ch. Alk.; Michalopoulos, D.; Dimitrov, L.

    2008-02-01

    The reinforcing steel, used in concrete structures, when corroded causes reduction of the strength properties and especially drastic reduction of ductility. Steel corrosion constitutes an important factor of progressive devaluation of its mechanical properties and serious reduction of the integrity of structures. The problem becomes more evident specifically for structures near coastal areas where salt corrosion is predominant. Reinforced concrete columns and beams are quite often extended by welding new steel reinforcement to the already corroded existing steel. In the present article the impact of corrosion on the mechanical properties of welded splices of reinforcing Steel S400 and B500c is examined. An experimental investigation was conducted and tensile and compressive results are presented for welded precorroded S400 and noncorroded B500c steel splices. The mechanical behavior of welded splices in tension are different in compression and depend strongly on the level of corrosion of the S400 bars.

  15. Mechanical and Corrosive Properties of Two Magnesium Wires: Mg4Gd and Mg6Ag

    Science.gov (United States)

    Maier, Petra; Szakács, Gabor; Wala, Marcin; Hort, Norbert

    The mechanical and corrosive properties of two Magnesium wires are studied in the field of microhardness, tension-, compression-and 3-point-bending tests, corrosion and its influence on the mechanical properties. Due to recrystallization during their complex forming processes (casting, extrusion, wire drawing), both wires show a fine grained microstructure resulting in high strength and ductility. However, the ductility is mostly evaluated by 3-point bending and compression; due to the notch effect in the clamp area, the maximum tensile strength and elongation under tension cannot be measured. Both alloys show a tensile-compressive yield asymmetry. Even RE-elements are known to reduce this asymmetry, the Mg-Gd alloy shows 100 MPa higher strength in tension than compression. The asymmetry of the Mg-Ag wire is similar. Overall the wires show very high strength and hardness, Mg6Ag slightly higher compared to Mg4Gd. Strong pitting corrosion is found and reduces strongly the tensile and bending strength.

  16. Some peculiarities of corrosion of wheel steel

    Directory of Open Access Journals (Sweden)

    Alexander SHRAMKO

    2009-01-01

    Full Text Available Corrosion mechanism and rate of different chemical composition and structural condition of wheel steel were investigated. It was shown that “white layers”, variation in grain size and banding of wheel steel structure results in corrosion rate. Microstructure of steel from different elements of railway wheels after operation with corrosion was investigated. Wheel steel with addition of vanadium corroded more quickly than steel without vanadium. Non-metallic inclusions are the centre of corrosion nucleation and their influence on corrosion depends on type of inclusion. Mechanism of corrosion of wheel steel corrosion was discussed.

  17. Diffusion Coatings as Corrosion Inhibitors

    Science.gov (United States)

    Ivanov, Radoslav; Ignatova-Ivanova, Tsveteslava

    2016-03-01

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

  18. Corrosion behavior of duplex coatings

    Directory of Open Access Journals (Sweden)

    K. Raghu Ram Mohan Reddy

    2016-07-01

    Full Text Available The titanium alloys are used in defense, aerospace, automobile, chemical plants and biomedical applications due to their very high strength and lightweight properties. However, corrosion is a life-limiting factor when Ti alloys are exposed to different chemical environments at high temperatures. In the present paper, duplex NiCrAlY/WC–Co coating is coated onto Ti6Al4V substrate to investigate the corrosion behavior of both coated samples and the substrate. The duplex coating was performed with NiCrAlY as the intermediate coat of 200 μm thickness deposited by HVOF process and WC–Co ceramic top coat with varying thicknesses of 250 μm, 350 μm and 450 μm deposited by DS process. Potentiodynamic polarization tests were employed to investigate the corrosion performance of duplex coated samples and substrate in Ringer’s solution at 37 °C and pH value was set to 5.7. Finally the results reveal that 350 μm thick coated samples showed highest corrosion resistance compared to 250 μm thick samples as well as bare substrate. However, the 450 μm thick coated sample showed poor corrosion resistance compared to the substrate. The scale formed on the samples upon corrosion was characterized by using SEM analysis to understand the degree of corrosion behavior.

  19. Diffusion Coatings as Corrosion Inhibitors

    Directory of Open Access Journals (Sweden)

    Ivanov Radoslav

    2016-03-01

    Full Text Available Corrosion is the cause of irretrievable loss of huge amounts of metals and alloys. The harmful effects of corrosion can be reduced significantly by applying appropriate methods of corrosion protection. One method to protect metals against corrosion is the formation of diffusion coatings on them. High corrosion resistance is typical for the boride diffusion layers. Aluminothermy is one of the main methods for diffusion saturation of the surface of metal products with various elements, including boron, and under certain conditions with aluminum, too. Samples of steel 45 were put to aluminothermic diffusion saturation with boron in a pressurized steel container at a temperature of 1100K, for 6 hours in powdered aluminothermic mixtures. The content of В2О3 in the starting mixtures decreased from the optimum - 20% to 0%, and the content of Al and the activator - (NH42.4BF3 is constant, respectively 7% and 0.5%. Al2O3 was used as filler. The borided samples were tested for corrosion resistance in 10% HCl for 72 hours. The results show that their corrosion resistance depends on the composition of the starting saturating mixture (mainly on the content of В2О3, and respectively on the composition, structure, thickness and degree of adhesion of the layer to the metal base.

  20. Corrosion protection and control using nanomaterials

    CERN Document Server

    Cook, R

    2012-01-01

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

  1. Traumatic tension pneumocephalus: Two case reports

    Directory of Open Access Journals (Sweden)

    Abubaker Al-Aieb

    2017-01-01

    Conclusions: These are two rare cases with posttraumatic tension pneumocephalus treated conservatively with a favorable outcome. Early diagnosis of tension pneumocephalus is a crucial step to facilitate early recovery; however, the associated injuries need attention as they could influence the hospital course.

  2. Tension and robustness in multitasking cellular networks.

    Directory of Open Access Journals (Sweden)

    Jeffrey V Wong

    Full Text Available Cellular networks multitask by exhibiting distinct, context-dependent dynamics. However, network states (parameters that generate a particular dynamic are often sub-optimal for others, defining a source of "tension" between them. Though multitasking is pervasive, it is not clear where tension arises, what consequences it has, and how it is resolved. We developed a generic computational framework to examine the source and consequences of tension between pairs of dynamics exhibited by the well-studied RB-E2F switch regulating cell cycle entry. We found that tension arose from task-dependent shifts in parameters associated with network modules. Although parameter sets common to distinct dynamics did exist, tension reduced both their accessibility and resilience to perturbation, indicating a trade-off between "one-size-fits-all" solutions and robustness. With high tension, robustness can be preserved by dynamic shifting of modules, enabling the network to toggle between tasks, and by increasing network complexity, in this case by gene duplication. We propose that tension is a general constraint on the architecture and operation of multitasking biological networks. To this end, our work provides a framework to quantify the extent of tension between any network dynamics and how it affects network robustness. Such analysis would suggest new ways to interfere with network elements to elucidate the design principles of cellular networks.

  3. Normal-tension glaucoma (Low-tension glaucoma

    Directory of Open Access Journals (Sweden)

    Anderson Douglas

    2011-12-01

    Full Text Available Glaucoma is now considered an abnormal physiology in the optic nerve head that interacts with the level of intraocular pressure (IOP, with the degree and rate of damage depending on the IOP and presumably the degree of abnormal physiology. Diagnosis of normal-tension glaucoma (NTG, defined as glaucoma without a clearly abnormal IOP, depends on recognizing symptoms and signs associated with optic nerve vulnerability, in addition to absence of other explanations for disc abnormality and visual field loss. Among the findings are a halo or crescent of absence of retinal pigment epithelium around the disc, bilateral pre-chiasmal visual field defects, splinter hemorrhages at the disc margin, vascular dysregulation (low blood pressure, cold hands and feet, migraine headache with aura, and the like, or a family history of glaucoma. Possibly relevant, is a history of hemodynamic crisis, arterial obstructive disease, or sleep apnea. Neurological evaluation with imaging is needed only for atypical cases or ones that progress unexpectedly. Management follows the same principle of other chronic glaucomas, to lower the IOP by a substantial amount, enough to prevent disabling visual loss. However, many NTG cases are non-progressive. Therefore, it may often be wisein mild cases to determine whether the case is progressive and the rate of progression before deciding on how aggressivene to be with therapy. Efforts at neuroprotection and improvement in blood flow have not yet been shown effective.

  4. Corrosion Protection of Electrically Conductive Surfaces

    OpenAIRE

    Jian Song; Liangliang Wang; Andre Zibart; Christian Koch

    2012-01-01

    The basic function of the electrically conductive surface of electrical contacts is electrical conduction. The electrical conductivity of contact materials can be largely reduced by corrosion and in order to avoid corrosion, protective coatings must be used. Another phenomenon that leads to increasing contact resistance is fretting corrosion. Fretting corrosion is the degradation mechanism of surface material, which causes increasing contact resistance. Fretting corrosion occurs when there is...

  5. Critical Study of Corrosion Damaged Concrete Structures

    OpenAIRE

    Sallehuddin Shah Ayop; John Cairns

    2013-01-01

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

  6. Shutdown corrosion in geothermal energy systems

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Peter F.

    1982-10-08

    Experience has shown that corrosion occurring during geothermal energy utilization system downtime--shutdown corrosion--can pose a serious threat to successful operations. Shutdown corrosion in geothermal plants appears more severe than would be expected in their nongeothermal analogs, and its mitigation may pose a severe challenge to corrosion engineering personnel. This paper presents four case histories of geothermal shutdown corrosion problems. General methods of mitigation are explored.

  7. Cracking and corrosion recovery boiler

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-12-31

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

  8. Corrosion-resistant coating development

    Energy Technology Data Exchange (ETDEWEB)

    Stinton, D.P.; Kupp, D.M.; Martin, R.L. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  9. Corrosion-resistant sulfur concretes

    Science.gov (United States)

    McBee, W. C.; Sullivan, T. A.; Jong, B. W.

    1983-04-01

    Sulfur concretes have been developed by the Bureau of Mines as construction materials with physical and mechanical properties that suit them for use in acid and salt corrosive environments where conventional concretes fail. Mixture design methods were established for preparing sulfur concretes using different types of aggregates and recently developed mixed-modified sulfur cements. Bench-scale testing of the sulfur concretes has shown their potential value. Corrosion resistance, strength, and durability of sulfur concrete are superior to those of conventional materials. Field in situ evaluation tests of the sulfur concretes as replacement for conventional concrete materials are in progress in corrosive areas of 24 commercial chemical, fertilizer, and metallurgical plants.

  10. Review on Stress Corrosion and Corrosion Fatigue Failure of Centrifugal Compressor Impeller

    Institute of Scientific and Technical Information of China (English)

    SUN Jiao; CHEN Songying; QU Yanpeng; LI Jianfeng

    2015-01-01

    Corrosion failure, especially stress corrosion cracking and corrosion fatigue, is the main cause of centrifugal compressor impeller failure. And it is concealed and destructive. This paper summarizes the main theories of stress corrosion cracking and corrosion fatigue and its latest developments, and it also points out that existing stress corrosion cracking theories can be reduced to the anodic dissolution (AD), the hydrogen-induced cracking (HIC), and the combined AD and HIC mechanisms. The corrosion behavior and the mechanism of corrosion fatigue in the crack propagation stage are similar to stress corrosion cracking. The effects of stress ratio, loading frequency, and corrosive medium on the corrosion fatigue crack propagation rate are analyzed and summarized. The corrosion behavior and the mechanism of stress corrosion cracking and corrosion fatigue in corrosive environments, which contain sulfide, chlorides, and carbonate, are analyzed. The working environments of the centrifugal compressor impeller show the behavior and the mechanism of stress corrosion cracking and corrosion fatigue in different corrosive environments. The current research methods for centrifugal compressor impeller corrosion failure are analyzed. Physical analysis, numerical simulation, and the fluid-structure interaction method play an increasingly important role in the research on impeller deformation and stress distribution caused by the joint action of aerodynamic load and centrifugal load.

  11. Magnetic Tension of Sunspot Fine Structures

    CERN Document Server

    Venkatakrishnan, P

    2010-01-01

    The equilibrium structure of sunspots depends critically on its magnetic topology and is dominated by magnetic forces. Tension force is one component of the Lorentz force which balances the gradient of magnetic pressure in force-free configurations. We employ the tension term of the Lorentz force to clarify the structure of sunspot features like penumbral filaments, umbral light bridges and outer penumbral fine structures. We compute vertical component of tension term of Lorentz force over two active regions namely NOAA AR 10933 and NOAA AR 10930 observed on 05 January 2007 and 12 December 2006 respectively. The former is a simple while latter is a complex active region with highly sheared polarity inversion line (PIL). The vector magnetograms used are obtained from Hinode(SOT/SP). We find an inhomogeneous distribution of tension with both positive and negative signs in various features of the sunspots. The existence of positive tension at locations of lower field strength and higher inclination is compatible...

  12. Subacute Tension Hemopneumothorax with Novel Electrocardiogram Findings

    Directory of Open Access Journals (Sweden)

    Saks, Mark A

    2010-02-01

    Full Text Available This case report describes a patient with a subacute right-sided tension hemopneumothorax following an occult stab. The patient’s electrocardiogram (ECG, performed as part of a standardized triage process, demonstrated significant abnormalities that misguided initial resuscitation, but resolved following evacuation of the tension hemopneumothorax. Tension pneumothorax is typically regarded as an immediately life-threatening condition that requires emergent management with needle or tube thoracostomy. However, we believe that subacute tension pneumothorax may be a rarely observed clinical phenomenon and may lead to unique ECG findings. We believe that the ECG changes we observed provided an early clue to the eventual diagnosis of a subacute tension pneumothorax and have not been previously described in this setting. . [West J Emerg Med. 2010; 11(1:86-89].

  13. FORMULAS OF TENSION OF CONTINUOUS ROLLING PROCESS

    Institute of Scientific and Technical Information of China (English)

    J.Z. Zhang; X.P. Zhang

    2007-01-01

    The development of computer controlled continuous rolling process calls for a mathematicalexpression that can express the inequality condition of "constant flow". Tension is the link of thecontinuous rolling process. From the condition of dynamic equilibrium, a differential equation oftension is given out. On the basis of the physical rules established from the industrial practice andexperimental studies, the law of volume constancy, the linear relation of forward slip and tension,the state equation of continuous rolling, the formula of dynamic tension, and the formula of statictension have been obtained. These formulae reflect the functional relations between tensions,thickness, roll velocity, and time in the continuous rolling process. It is implied that the continuousrolling process is a gradually steady, controllable, and measurable dynamic system. An assumptionof predicting the thickness of a steel plate using these tension formulae is also put forward.

  14. Erosion--Corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Vyas, B.

    1978-01-01

    The deterioration of materials by corrosion or erosion by itself presents a formidable problem and for this reason investigators have studied these two phenomena independently. In fact, there are very few systematic studies on E-C and the majority of references mention it only in passing. In most real systems, however, the two destructive processes take place simultaneously, hence the purpose of this review is to present the various interactions between the chemical and mechanical agents leading to accelerated degradation of the material. The papers cited in the review are those that lead to a better understanding of the process involved in the accelerated rate of material loss under E-C conditions.

  15. Greener Approach towards Corrosion Inhibition

    Directory of Open Access Journals (Sweden)

    Neha Patni

    2013-01-01

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

  16. Corrosion Problems in Absorption Chillers

    Science.gov (United States)

    Stetson, Bruce

    1978-01-01

    Absorption chillers use a lithium bromide solution as the medium of absorption and water as the refrigerant. Discussed are corrosion and related problems, tests and remedies, and cleaning procedures. (Author/MLF)

  17. Uniaxial tension of drying sieves

    Directory of Open Access Journals (Sweden)

    Bojić Nada V.

    2013-01-01

    Full Text Available Although the literature contains numerous studies that have been developed to describe the nonlinear behavior of drying sieves' operation, there are no papers in this which report deeper investigation of the drying sieve behavior when exposed to tension and thermo stabilization. The aim of this paper is to provide insight into the elastoplastic behavior of the thermo stabilized and not stabilized sieves subjected to the tensile force. Within this work both theoretical and experimental investigations were performed. The sieves were joined by using a spiral. In separate experiments tests of wire base and weft of the weave mesh were performed, both for thermo stabilized and not thermo stabilized sieves, sieves joining and the sieve thermo stabilization itself. It was established that the thermo stabilization of sieves provides for stability of sieves' dimensions and that open thermo stabilized drying sieve exhibits better mechanical properties and exploitation characteristics then the sieves joining. [Projekat Ministarstva nauke Republike Srbije, br. ON174004: Micromechanics criteria of damage and fracture and br. TR 32036: Development of software for solving the coupled multi-physical problems

  18. Accelerated corrosion test and corrosion failure distribution model of aircraft structural aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Wen-lin; MU Zhi-tao; JIN Ping

    2006-01-01

    Based on corrosion damage data of 10 years for a type of aircraft aluminum alloy, the statistical analysis was conducted by Gumbel, Normal and two parameters Weibull distribution function. The results show that aluminum alloy structural member has the corrosion history of pitting corrosion-intergranular corrosion-exfoliation corrosion, and the maximum corrosion depth is in conformity to normal distribution. The accelerated corrosion test was carried out with the complied equivalent airport accelerated environment spectrum. The corrosion damage failure modes of aluminum alloy structural member indicate that the period of validity of the former protective coating is about 2.5 to 3 years, and that of the novel protective coating is about 4.0 to 4.5 years. The corrosion kinetics law of aluminum spar flange was established by fitting corrosion damage test data. The law indicates two apparent corrosion stages of high strength aluminum alloy section material: pitting corrosion and intergranular corrosion/exfoliation corrosion.The test results agree with the statistical fit result of corrosion data collected from corrosion member in service. The fractional error is 5.8% at the same calendar year. The accelerated corrosion test validates the corrosion kinetics law of aircraft aluminum alloy in service.

  19. Electrochemical Studies of Atmospheric Corrosion.

    Science.gov (United States)

    1979-01-01

    Todynamlc polarization curves using a mod ifiedatmospheric corrosion mon i tor (ACM). Norma l Tafel behavior was observed , the limiting current for oxygen...following a suggestion of Peter Serada, who is heading a task group on time-of-wetness measurements In ASTM GO1 .04, in which the author is participating...about 5 papers except for 1968 where a symposium on atmospheric corrosion was held which resulted in the publ ication of an ASTM Special Technical

  20. Corrosion Control Anniston Army Depot

    Science.gov (United States)

    2010-02-09

    parts. • Anodize, Chrome, and Black Oxide (et.al.) • Substrate Prep and CARC paint. Stowage • Climate controlled storage (limited). • Weather...resistant (rain, uv) stowage . • Right Material – Right Time In Process Actions Bldgs 129 and 114 • Installation of new cleaning technologies for small... Rack Dehydration Prep Area CARC Application Flash-Off Oven De-mask and Anti- Corrosion App. Planned Future Actions Survey • Perform a corrosion survey

  1. Materials selection and corrosion problems

    Energy Technology Data Exchange (ETDEWEB)

    Cornet, I.; Greif, R.; Treseder, R.S.

    1974-06-28

    Data tabulated for chemical composition of geothermal waters are presented for four areas of interest in Nevada: Beowawe steam well and Beowawe Hot Spring, Buffalo Valley Hot Springs, Kyle Hot Springs, and Leach Hot Springs. Material recommendations were prepared for the Nevada geothermal well. A detailed field corrosion test program planned for the Nevada test well is included. A progress report is presented for a laboratory research program on velocity effects in corrosion. (MHR)

  2. Maintainability Improvement Through Corrosion Prediction

    Science.gov (United States)

    1997-12-01

    potential, current, pH, and chloride ion concentration were made along a simulated corrosion fatigue crack for HY80 (UNS K31820) steel in seawater...frequency range of 0.05-50 Hz, a 7075-T6 aluminium alloy and 304 and 316L stainless steels were fatigue tested in 3.0% NaCl solution. The increments...DESCRIPTORS: Conference Paper; Aluminum base alloys- Mechanical properties; Austenitic stainless steels - Mechanical properties; Corrosion fatigue

  3. Corrosion resistant neutron absorbing coatings

    Science.gov (United States)

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

    2012-05-29

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

  4. The surface tension of liquid gallium

    Science.gov (United States)

    Hardy, S. C.

    1985-01-01

    The surface tension of liquid gallium has been measured using the sessile drop technique in an Auger spectrometer. The experimental method is described. The surface tension in mJ/sq m is found to decrease linearly with increasing temperature and may be represented as 708-0.66(T-29.8), where T is the temperature in centigrade. This result is of interest because gallium has been suggested as a model fluid for Marangoni flow experiments. In addition, the surface tension is of technological significance in the processing of compound semiconductors involving gallium.

  5. Surface tension profiles in vertical soap films

    Science.gov (United States)

    Adami, N.; Caps, H.

    2015-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

  6. Computer-aided design of tension structures

    OpenAIRE

    Ong, C.F.

    1992-01-01

    This thesis consists of three parts. Part I (chapters 1-4) gives a review and description of the basis for the numerical modelling of tension structures. The discussion in Part I leads to the conclusion of a need for an interactive design procedure for tension structures which is the subject under consideration in Part II (chapters 5-7). In the design of tension structures, an area which requires special attention is the dynamic response often initiated by the action of a natural wind. In Par...

  7. Investigations on Atmospheric Corrosion of Low carbon Steel in ...

    African Journals Online (AJOL)

    Nafiisah

    2008-07-17

    Jul 17, 2008 ... index which is directly related to the weight loss due to corrosion. The corrosion index ... easily observed by visual inspection, and the robust Gaussian filter was used. .... Method of removal of corrosion products from corrosion.

  8. Migrating corrosion inhibitor protection of concrete

    Energy Technology Data Exchange (ETDEWEB)

    Bjegovic, D.; Miksic, B.

    1999-11-01

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

  9. Solutions of corrosion Problems in advanced Technologies

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Karlsson, Asger

    1999-01-01

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

  10. Corrosion behavior of corrosion resistant alloys in stimulation acids

    Energy Technology Data Exchange (ETDEWEB)

    Cheldi, Tiziana [ENI E and P Division, 20097 San Donato Milanese Milano (Italy); Piccolo, Eugenio Lo; Scoppio, Lucrezia [Centro Sviluppo Materiali, via Castel Romano 100, 00128 Rome (Italy)

    2004-07-01

    In the oil and gas industry, selection of CRAs for downhole tubulars is generally based on resistance to corrosive species in the production environment containing CO{sub 2}, H{sub 2}S, chloride and in some case elemental sulphur. However, there are non-production environments to which these materials must also be resistant for either short term or prolonged duration; these environments include stimulation acids, brine and completion fluids. This paper reports the main results of a laboratory study performed to evaluate the corrosion and stress corrosion behaviour to the acidizing treatments of the most used CRAs for production tubing and casing. Laboratory tests were performed to simulate both 'active' and 'spent' acids operative phases, selecting various environmental conditions. The selected steel pipes were a low alloyed steel, martensitic, super-martensitic, duplex 22 Cr, superduplex 25 Cr and super-austenitic stainless steels (25 Cr 35 Ni). Results obtained in the 'active' acid environments over the temperature range of 100-140 deg. C, showed that the blend acids with HCl at high concentration and HCl + HF represented too much severe conditions, where preventing high general corrosion and heavy localised corrosion by inhibition package becomes very difficult, especially for duplex steel pipe, where, in some case, the specimens were completely dissolved into the solution. On the contrary, all steels pipes were successfully protected by inhibitor when organic acid solution (HCOOH + CH{sub 3}COOH) were used. Furthermore, different effectiveness on corrosion protection was showed by the tested inhibitors packages: e.g. in the 90% HCl at 12% + 10 CH{sub 3}COOH acid blend. In 'spent' acid environments, all steel pipes showed to be less susceptible to the localised and general corrosion attack. Moreover, no Sulphide Stress Corrosion Cracking (SSC) was observed. Only one super-austenitic stainless steel U-bend specimen showed

  11. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua

    2004-09-16

    The repository design includes a drip shield (BSC 2004 [DIRS 168489]) that provides protection for the waste package both as a barrier to seepage water contact and a physical barrier to potential rockfall. The purpose of the process-level models developed in this report is to model dry oxidation, general corrosion, and localized corrosion of the drip shield plate material, which is made of Ti Grade 7. This document is prepared according to ''Technical Work Plan For: Regulatory Integration Modeling and Analysis of the Waste Form and Waste Package'' (BSC 2004 [DIRS 171583]). The models developed in this report are used by the waste package degradation analyses for TSPA-LA and serve as a basis to determine the performance of the drip shield. The drip shield may suffer from other forms of failure such as the hydrogen induced cracking (HIC) or stress corrosion cracking (SCC), or both. Stress corrosion cracking of the drip shield material is discussed in ''Stress Corrosion Cracking of the Drip Shield, the Waste Package Outer Barrier, and the Stainless Steel Structural Material'' (BSC 2004 [DIRS 169985]). Hydrogen induced cracking of the drip shield material is discussed in ''Hydrogen Induced Cracking of Drip Shield'' (BSC 2004 [DIRS 169847]).

  12. Corrosion of steel structures in sea-bed sediment

    Indian Academy of Sciences (India)

    Xiutong Wang; Jizhou Duan; Yan Li; Jie Zhang; Shide Ma; Baorong Hou

    2005-04-01

    Seabed sediment (SBS) is a special soil that is covered by seawater. With the developments in marine oil exploitation and engineering, more and more steel structures have been buried in SBS. SBS corrosion has now become a serious problem in marine environment and an important issue in corrosion science. In this paper, approach in the field of SBS corrosion is reviewed. Electrochemical and microbial corrosion factors, corrosion mechanism, measurement of metal corrosion rate, corrosion evaluation and prediction of corrosion are also discussed here.

  13. Tension-Type and Other Primary Headaches

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2005-12-01

    Full Text Available A review of the literature on tension-type and other “nonmigrainous” primary headaches is presented from Children’s Hospital of the King’s Daughters, Eastern Virginia Medical School, Norfolk, VA.

  14. The Dynamic Surface Tension of Water.

    Science.gov (United States)

    Hauner, Ines M; Deblais, Antoine; Beattie, James K; Kellay, Hamid; Bonn, Daniel

    2017-03-23

    The surface tension of water is an important parameter for many biological or industrial processes, and roughly a factor of 3 higher than that of nonpolar liquids such as oils, which is usually attributed to hydrogen bonding and dipolar interactions. Here we show by studying the formation of water drops that the surface tension of a freshly created water surface is even higher (∼90 mN m(-1)) than under equilibrium conditions (∼72 mN m(-1)) with a relaxation process occurring on a long time scale (∼1 ms). Dynamic adsorption effects of protons or hydroxides may be at the origin of this dynamic surface tension. However, changing the pH does not significantly change the dynamic surface tension. It also seems unlikely that hydrogen bonding or dipole orientation effects play any role at the relatively long time scale probed in the experiments.

  15. Transcutaneous Determination of Arterial Oxygen Tension

    Science.gov (United States)

    Fenner, A.; And Others

    1975-01-01

    Evaluated were two techniques (the conventional method and the new transcutaneous method) of measuring arterial oxygen tension in 20 severely ill preterm and term infants and in 70 healthy infants. (Author/CL)

  16. Psychology--tensions between objectivity and subjectivity.

    Science.gov (United States)

    Klempe, Sven Hroar

    2012-09-01

    The self is often defined in terms of its presentational appearances. This may easily end up in a denial of the internal aspects of the self, which is very often related to a tendency to avoid the tension between the internal and the external, but also between subjectivity and objectivity. In this paper this ambition is regarded in a historical perspective, in which Fichte and Hegel both represent attempts at abolishing the tension, whereas Kant and Kierkegaard represent the opposite. History shows that an eradication of the tension between subjectivity and objectivity implies a deterioration of psychology as well. Thus the conclusion is that psychology is primarily to be defined in terms of the tension between subjectivity and objectivity, which requires an accurate understanding and the inclusion of both of them.

  17. Oxygen tension level and human viral infections.

    Science.gov (United States)

    Morinet, Frédéric; Casetti, Luana; François, Jean-Hugues; Capron, Claude; Pillet, Sylvie

    2013-09-01

    The role of oxygen tension level is a well-known phenomenon that has been studied in oncology and radiotherapy since about 60 years. Oxygen tension may inhibit or stimulate propagation of viruses in vitro as well as in vivo. In turn modulating oxygen metabolism may constitute a novel approach to treat viral infections as an adjuvant therapy. The major transcription factor which regulates oxygen tension level is hypoxia-inducible factor-1 alpha (HIF-1α). Down-regulating the expression of HIF-1α is a possible method in the treatment of chronic viral infection such as human immunodeficiency virus infection, chronic hepatitis B and C viral infections and Kaposi sarcoma in addition to classic chemotherapy. The aim of this review is to supply an updating concerning the influence of oxygen tension level in human viral infections and to evoke possible new therapeutic strategies regarding this environmental condition. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Report on accelerated corrosion studies.

    Energy Technology Data Exchange (ETDEWEB)

    Mowry, Curtis Dale; Glass, Sarah Jill; Sorensen, Neil Robert

    2011-03-01

    Sandia National Laboratories (SNL) conducted accelerated atmospheric corrosion testing for the U.S. Consumer Product Safety Commission (CPSC) to help further the understanding of the development of corrosion products on conductor materials in household electrical components exposed to environmental conditions representative of homes constructed with problem drywall. The conditions of the accelerated testing were chosen to produce corrosion product growth that would be consistent with long-term exposure to environments containing humidity and parts per billion (ppb) levels of hydrogen sulfide (H{sub 2}S) that are thought to have been the source of corrosion in electrical components from affected homes. This report documents the test set-up, monitoring of electrical performance of powered electrical components during the exposure, and the materials characterization conducted on wires, screws, and contact plates from selected electrical components. No degradation in electrical performance (measured via voltage drop) was measured during the course of the 8-week exposure, which was approximately equivalent to 40 years of exposure in a light industrial environment. Analyses show that corrosion products consisting of various phases of copper sulfide, copper sulfate, and copper oxide are found on exposed surfaces of the conductor materials including wires, screws, and contact plates. The morphology and the thickness of the corrosion products showed a range of character. In some of the copper wires that were observed, corrosion product had flaked or spalled off the surface, exposing fresh metal to the reaction with the contaminant gasses; however, there was no significant change in the wire cross-sectional area.

  19. Detective probe prevents corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2001-07-01

    A black liquor recovery boiler is the main investment in a pulp mill, accounting for: about a third of the total cost of FIM 3-4 billion. Environmental aspects required that all the harmful chemicals involved in the process have to be kept within a pulp mill, rather than be released outside, and closed water circulation systems have to be introduced. These have led to the enrichment of some process and non-process chemicals causing corrosion problems and process disturbances in the boiler. The recovery boiler receives the liquor after the digestion stage, i.e. when woodchips are cooked to make cellulose, and burns it. During digestion, the wood produces out lignin, mixed with the liquor (consisting of sodium sulphide and hydroxide). The black liquor is burnt at the bottom of the boiler after the organic parts have been fired off. The rest goes into the recovery system and the chemicals are recycled producing energy, saving repurchasing chemicals and protecting the environment from toxic emissions.

  20. Tension Hydrothorax Related to Disseminated Endometriosis

    Directory of Open Access Journals (Sweden)

    AnnaKate Deal, MD

    2016-01-01

    Full Text Available We present the case of a 34-year-old woman presenting to the emergency department (ED with dyspnea, cough, and fever. She was found to have a tension hydrothorax and was treated with ultrasound-guided thoracentesis in the ED. Subsequent inpatient evaluation showed the patient had disseminated endometriosis. Tension hydrothorax has not been previously described in the literature as a complication of this disease.

  1. The Tensions of In Situ Visualization.

    Science.gov (United States)

    Moreland, Kenneth

    2016-01-01

    In situ visualization is the coupling of visualization software with a simulation or other data producer to process the data "in memory" before the data are offloaded to a storage system. Although in situ visualization provides superior analysis, it has implementation tradeoffs resulting from conflicts with some traditional expected requirements. Numerous conflicting requirements create tensions that lead to difficult implementation tradeoffs. This article takes a look at the most prevailing tensions of in situ visualization.

  2. Oxygen tension level and human viral infections

    Energy Technology Data Exchange (ETDEWEB)

    Morinet, Frédéric, E-mail: frederic.morinet@sls.aphp.fr [Centre des Innovations Thérapeutiques en Oncologie et Hématologie (CITOH), CHU Saint-Louis, Paris (France); Université Denis Diderot, Sorbonne Paris Cité Paris, Paris (France); Casetti, Luana [Institut Cochin INSERM U1016, Paris (France); François, Jean-Hugues; Capron, Claude [Institut Cochin INSERM U1016, Paris (France); Laboratoire d' Hématologie, Hôpital Ambroise Paré, Boulogne (France); Université de Versailles Saint-Quentin en Yvelynes, Versailles (France); Pillet, Sylvie [Laboratoire de Bactériologie-Virologie-Hygiène, CHU de Saint-Etienne, Saint-Etienne (France); Université de Lyon et Université de Saint-Etienne, Jean Monnet, GIMAP EA3064, F-42023 Saint-Etienne, Lyon (France)

    2013-09-15

    The role of oxygen tension level is a well-known phenomenon that has been studied in oncology and radiotherapy since about 60 years. Oxygen tension may inhibit or stimulate propagation of viruses in vitro as well as in vivo. In turn modulating oxygen metabolism may constitute a novel approach to treat viral infections as an adjuvant therapy. The major transcription factor which regulates oxygen tension level is hypoxia-inducible factor-1 alpha (HIF-1α). Down-regulating the expression of HIF-1α is a possible method in the treatment of chronic viral infection such as human immunodeficiency virus infection, chronic hepatitis B and C viral infections and Kaposi sarcoma in addition to classic chemotherapy. The aim of this review is to supply an updating concerning the influence of oxygen tension level in human viral infections and to evoke possible new therapeutic strategies regarding this environmental condition. - Highlights: • Oxygen tension level regulates viral replication in vitro and possibly in vivo. • Hypoxia-inducible factor 1 (HIF-1α) is the principal factor involved in Oxygen tension level. • HIF-1α upregulates gene expression for example of HIV, JC and Kaposi sarcoma viruses. • In addition to classical chemotherapy inhibition of HIF-1α may constitute a new track to treat human viral infections.

  3. Corrosion in Electronic Devices and Sensors to Prevent Corrosion

    Directory of Open Access Journals (Sweden)

    Siddharth Dev

    2014-02-01

    Full Text Available Many types of metal and alloys are used in various electronic devices and components like computers, microchips, printed circuit board (PCB, integrated circuits, transistors, and diodes etc. Such components have variety of applications in the field of medical, aerospace, automotive sectors, telecommunication and defense. These components are exposed to different types of environments. The increased used of electronics has also increased the demand for reliability. The size of electronic equipment is also very significant parameter and it has been decreasing presently at a faster rate. The smaller size of equipment has undetectable failures. Though the corrosion taking place in electronic components is generally of micro level which can not be detected easily but the services of device are seized. The paper deals with the various types of corrosion in electronic components as a case study and an approach towards development of some sensor for corrosion monitoring.

  4. Morphology, geology and geochemistry of the "Salar del Gran Bajo del Gualicho" (Rio Negro, Argentina)

    Science.gov (United States)

    Angelucci, A.; Barbieri, M.; Brodtkorb, A.; Ciccacci, S.; Civitelli, G.; De Barrio, R.; Di, Filippo M.; Fredi, P.; Friedman, I.; Lombardi, S.; Schalamuk, A.I.; Toro, B.

    1996-01-01

    A multidisciplinary study of the Gran Bajo del Gualicho area (Rio Negro - Argentina) was carried out; the aim was to delineate its geological and geomorphological evolution and to estabilish the genesis of salts filling the depression. Climatic conditions were analized first to individuate their role in the present morphogenetic processes; moreover the main morphological features of present landscape were examined as well as the stratigraphy of the outcropping formations, and of the Gran Bajo del Gualicho Formation in particular. Finally, a possible geomorphological evolution of the studied area was traced. Geophysical analyses allowed to estabilish that the paleosurface shaped on the crystalline basement is strongly uneven and shows evidence of the strong tectonic phases it underwent. The result of isotope analyses confirmed that the salt deposits on the Gran Bajo del Gualicho bottom were produced by fresh water evaporation, while strontium isotope ratio suggested that such waters were responsible for solubilization of more ancient evaporitic deposits.

  5. Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading during zebrafish epiboly.

    Science.gov (United States)

    Campinho, Pedro; Behrndt, Martin; Ranft, Jonas; Risler, Thomas; Minc, Nicolas; Heisenberg, Carl-Philipp

    2013-12-01

    Epithelial spreading is a common and fundamental aspect of various developmental and disease-related processes such as epithelial closure and wound healing. A key challenge for epithelial tissues undergoing spreading is to increase their surface area without disrupting epithelial integrity. Here we show that orienting cell divisions by tension constitutes an efficient mechanism by which the enveloping cell layer (EVL) releases anisotropic tension while undergoing spreading during zebrafish epiboly. The control of EVL cell-division orientation by tension involves cell elongation and requires myosin II activity to align the mitotic spindle with the main tension axis. We also found that in the absence of tension-oriented cell divisions and in the presence of increased tissue tension, EVL cells undergo ectopic fusions, suggesting that the reduction of tension anisotropy by oriented cell divisions is required to prevent EVL cells from fusing. We conclude that cell-division orientation by tension constitutes a key mechanism for limiting tension anisotropy and thus promoting tissue spreading during EVL epiboly.

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

    NARCIS (Netherlands)

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

    1987-01-01

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

  7. Synergy effect of naphthenic acid corrosion and sulfur corrosion in crude oil distillation unit

    Science.gov (United States)

    Huang, B. S.; Yin, W. F.; Sang, D. H.; Jiang, Z. Y.

    2012-10-01

    The synergy effect of naphthenic acid corrosion and sulfur corrosion at high temperature in crude oil distillation unit was studied using Q235 carbon-manganese steel and 316 stainless steel. The corrosion of Q235 and 316 in corrosion media containing sulfur and/or naphthenic acid at 280 °C was investigated by weight loss, scanning electron microscope (SEM), EDS and X-ray diffractometer (XRD) analysis. The results showed that in corrosion media containing only sulfur, the corrosion rate of Q235 and 316 first increased and then decreased with the increase of sulfur content. In corrosion media containing naphthenic acid and sulfur, with the variations of acid value or sulfur content, the synergy effect of naphthenic acid corrosion and sulfur corrosion has a great influence on the corrosion rate of Q235 and 316. It was indicated that the sulfur accelerated naphthenic acid corrosion below a certain sulfur content but prevented naphthenic acid corrosion above that. The corrosion products on two steels after exposure to corrosion media were investigated. The stable Cr5S8 phases detected in the corrosion products film of 316 were considered as the reason why 316 has greater corrosion resistance to that of Q235.

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

    NARCIS (Netherlands)

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

    1987-01-01

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

  9. Corrosion effects on friction factors

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-03-01

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

  10. Graphene: corrosion-inhibiting coating.

    Science.gov (United States)

    Prasai, Dhiraj; Tuberquia, Juan Carlos; Harl, Robert R; Jennings, G Kane; Rogers, Bridget R; Bolotin, Kirill I

    2012-02-28

    We report the use of atomically thin layers of graphene as a protective coating that inhibits corrosion of underlying metals. Here, we employ electrochemical methods to study the corrosion inhibition of copper and nickel by either growing graphene on these metals, or by mechanically transferring multilayer graphene onto them. Cyclic voltammetry measurements reveal that the graphene coating effectively suppresses metal oxidation and oxygen reduction. Electrochemical impedance spectroscopy measurements suggest that while graphene itself is not damaged, the metal under it is corroded at cracks in the graphene film. Finally, we use Tafel analysis to quantify the corrosion rates of samples with and without graphene coatings. These results indicate that copper films coated with graphene grown via chemical vapor deposition are corroded 7 times slower in an aerated Na(2)SO(4) solution as compared to the corrosion rate of bare copper. Tafel analysis reveals that nickel with a multilayer graphene film grown on it corrodes 20 times slower while nickel surfaces coated with four layers of mechanically transferred graphene corrode 4 times slower than bare nickel. These findings establish graphene as the thinnest known corrosion-protecting coating.

  11. NO3- and HSO3- Induced Corrosion of Simulated Archaeological Iron in Humid-Acid Atmosphere%潮湿大气中NO3-和HSO3-对模拟铸铁文物的腐蚀研究

    Institute of Scientific and Technical Information of China (English)

    曹霞; 许淳淳

    2005-01-01

    NO3- and HSO3- induced corrosion of simulated archaeological iron in humid-acid atmosphere was studied by using periodic wet-dry tests. Surface tension tests, electrochemical impedance measurement, stereoscopic microscopy and energy dispersive atomic X-ray analysis (EDAX) were used to investigate the corrosion processes and products. The results of mass loss measurement showed that the corrosion kinetics can be approximately described by △W - AtB. With the addition of NO3-, the value of B increases. NO3- acts as an inhibitor in the HSO3- bearing pollutant during the corrosion process. Both the electrochemical impedance measurement and surface tension test confirmed the result of mass loss measurement. In addition, we found that the attack of anions to the metal at the initial corrosion stage was in good agreement with their surface activity.

  12. Microencapsulation of Corrosion Indicators for Smart Coatings

    Science.gov (United States)

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

    2011-01-01

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

  13. Method For Testing Properties Of Corrosive Lubricants

    Science.gov (United States)

    Ohi, James; De La Cruz, Jose L.; Lacey, Paul I.

    2006-01-03

    A method of testing corrosive lubricating media using a wear testing apparatus without a mechanical seal. The wear testing apparatus and methods are effective for testing volatile corrosive lubricating media under pressure and at high temperatures.

  14. Condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México

    Directory of Open Access Journals (Sweden)

    CERÓN-MIRELES PRUDENCIA

    1997-01-01

    Full Text Available Objetivo. Estudiar la asociación entre condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México. Material y métodos. Se encuestaron 2 623 trabajadoras que atendieron sus partos en tres grandes hospitales de la Ciudad de México en 1992. Se obtuvo información sobre los principales factores biológicos y sociales que se asocian al bajo peso al nacer; asimismo, se determinó el estrés ocupacional utilizando el instrumento desarrollado por Karasek. Se utilizaron modelos de regresión logística para evaluar la relación de las condiciones de trabajo con el bajo peso al nacer, controlando por variables confusoras. Resultados. El bajo peso al nacer fue más alto en trabajadoras con jornadas mayores a 50 horas semanales (RM= 1.6; IC= 1.17, 2.28 y con conflictos laborales (RM= 1.5; IC= 1.0, 2.25. La falta de apoyo social tangible fue identificado como un factor de riesgo de bajo peso al nacer (RM= 1.7; IC= 1.20, 2.33. Las medidas preventivas laborales como el cambio de tareas, disminución de la jornada y las salidas por enfermedad no mostraron un efecto benéfico en el peso al nacer, a excepción de la licencia de maternidad; las madres que no la tuvieron mostraron una probabilidad 2.2 veces mayor para bajo peso al nacer (IC= 1.66, 2.93. Conclusiones. Estos hallazgos resaltan la importancia de identificar los factores de riesgo ocupacional en el embarazo..

  15. An Investigation of Corrosion Mitigation Strategies for Aging Post Tensioned Cables

    Science.gov (United States)

    2017-01-01

    current can be supplied by a solar panel and battery configuration, or by applying a rectifier to convert hydroelectric power from the structure from...thermal units (International Table) 1,055.056 joules degrees ( angle ) 0.01745329 radians degrees Fahrenheit (F-32)/1.8 degrees Celsius feet 0.3048 meters...resins, leakage in and of itself could be of concern in filled applications (Soltesz 2010). If a crack is at a high angle or vertical, the higher

  16. El basamento metamórfico de muy bajo a bajo grado de las estancias La Modesta y La Josefina, macizo del Deseado, provincia de Santa Cruz

    Directory of Open Access Journals (Sweden)

    P. Moreira

    2005-03-01

    Full Text Available En este trabajo se exponen los resultados de un relevamiento detallado de las metamorfitas de la Formación La Modesta en su localidad tipo. Estudios petrográficos, geoquímicos y estructurales de estas rocas permitieron identificar nuevas litologías que integran esta unidad (rocas calcosilicáticas, metavolcanitas básicas, turmalinitas y bancos de óxidos de Fe y Mn, posibilitaron además establecer que el grado metamórfico alcanzado ha sido de muy bajo a bajo en prehnita-pumpellita transicional a facies de esquistos verdes. Se reconoció una esquistosidad S1 subparalela a las superficies de sedimentación S0. Se ha reinterpretado su ubicación temporal sobre la base de una datación (errorcrona Rb-Sr: 413 ± 17 Ma. Además se correlaciona esta formación con otras unidades sedimentarias de bajo grado metamórfico de regiones aledañas del macizo del Deseado y separarla de las rocas del Complejo Río Deseado. Por último, se propone una posible evolución geológica pre-mesozoica para la zona a partir de un margen protopacífico.

  17. Filtro paso bajo discreto de operación directa sobre señales PWM

    OpenAIRE

    López Batres, Sergio

    2010-01-01

    Este proyecto aborda la construcción y diseño de un filtro de paso bajo que opera sobre señales moduladas en anchura de impulsos (PWM). Utiliza componentes analógicos y un microprocesador que efectúa el control del sistema. Su función es servir de atenuador de los armónicos en amplificadores de clase D que podrían usarse en sistemas de audio, sin necesidad de un filtro paso bajo analógico de orden elevado. Ingeniería Técnica en Electrónica

  18. PAJERO-GALLANÍA Y CASA DE ALTO Y BAJO [Material gráfico

    OpenAIRE

    Fundación para la Etnografía y el Desarrollo de la Artesanía Canaria

    1990-01-01

    Antiguedad: SIGLO XX CARRETERA GENERAL TEROR-SAN MATEO, JUNTO AL LUGAR CONOCIDO COMO EL OJERO, NOS METEMOS EN UNA VEREDA QUESUBE AL CASERIO. CASA DE ALTO Y BAJO, PLANTA RECTANGULAR Y PATIO EXTERIOR. BALCON Y CUBIERTA A DOS AGUAS CON TEJA FRANCESA. PAJERO-ALPENDRE DE ALTO Y BAJO. PIEDRA SIN ENFOSCAR. CUBIERTA A DOS AGUAS. Calificación del suelo: RÚSTICO DE PROTECCIÓN AGRARIA Clasificación del suelo: RÚSTICO Declaración BIC:No EN EL PAJAR, LAS PUERTAS NO SON LAS ORIGINALES, Y ...

  19. Materiales, tecnologías y prototipos de viviendas de muy bajo coste

    OpenAIRE

    Salas Serrano, Julián; Díaz-Romeral Bringas, Pablo

    1982-01-01

    Not available.El fin último de la investigación es el de conseguir unas tipologías de viviendas realizadas mediante materiales, procedimientos o sistemas constructivos que permitan proporcionar un producto final, cuyas características fundamentales sean: adecuación a las necesidades físicas y socioculturales de la zona y, prioritariamente, la consecución de un muy bajo coste da ejecución de las mismas. Cuando se habla a continuación de «viviendas de muy bajo coste» se debe entender que n...

  20. Aproximaciones hacia una definición de “Bajo Rendimiento Escolar”

    OpenAIRE

    Monsalve Cano, Henry de Jesús

    2016-01-01

    Artículo (Maestría en Educación y Desarrollo Humano). Universidad de Manizales. Facultad de Ciencias Sociales y Humanas. CINDE, 2016 No existe un criterio común que permita definir unívocamente el concepto de bajo rendimiento escolar (González 2003). Sin embargo, se pretende hacer un recorrido por las definiciones que del Bajo Rendimiento Escolar (BRE) han presentado teóricos e investigadores en las últimas cuatro décadas. Sabemos, eso sí, que ha dejado de ser un hecho aislado, sólo educat...

  1. LA INSATISFACCIÓN LABORAL COMO FACTOR DEL BAJO RENDIMIENTO DEL TRABAJADOR

    OpenAIRE

    Granda Carazas, Segundo Eloy; Facultad de Ciencias Contables, Universidad Nacional Mayor de San Marcos

    2014-01-01

    El tema "la insatisfacción laboral como factor del bajo rendimiento del trabajador" es importante, ya que se puede constatar que en algunas organizaciones, pese a sus significativos esfuerzos para ampliar y modernizar su infraestructura, afrontan problemas de rendimiento laboral. Este artículo se orienta a determinar en qué medida la insatisfacción laboral se asocia al bajo rendimiento laboral en una organización. Como factores constituyentes de la insatisfacción laboral se considerar...

  2. Vaso fermentador de bajo costo para la micropropagación masiva de jengibre

    OpenAIRE

    Alejandro Hern\\u00E1ndez-Soto; Andr\\u00E9s Gatica-Arias; Silvana Alvarenga-Venutolo

    2007-01-01

    Vaso fermentador de bajo costo para la micropropagación masiva de jengibre. La presente investigación se realizó en el Centro de Investigación en Biotecnología del Instituto Tecnológico de Costa Rica, durante el primer semestre del 2003 y tuvo como objetivo desarrollar un vaso fermentador de bajo costo para la micropropagación masiva de jengibre. El vaso fermentador propuesto en este trabajo tuvo un costo aproximado de $4 USD, con capacidad de utilizar de 50 a 75 brotes como material de parti...

  3. Factores nutricionales maternos y el bajo peso al nacer en un área de salud

    OpenAIRE

    Arley Rey Vilchez; Darehyne Ávila Piña; Amarelis Rodríguez Fuentes; Ana Celia Cabrera Iznaga

    2013-01-01

    Fundamento: el bajo peso al nacer es multifactorial y se atribuye a causas maternas, fetales y ambientales. Los hábitos alimentarios inadecuados unidos a otros factores nutricionales maternos son determinantes. Objetivo: identificar los factores nutricionales maternos relacionados con el bajo peso al nacer en pacientes del Área I del municipio Cienfuegos. Métodos: se realizó un estudio analítico, retrospectivo, de casos y controles entre enero 2006 y diciembre 2008. Se estudiaron 50 madres d...

  4. Smart Coatings for Launch Site Corrosion Protection

    Science.gov (United States)

    Calle, Luz M.

    2014-01-01

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

  5. Multicomponent Oxide Systems for Corrosion Protection.

    Science.gov (United States)

    1980-11-15

    and Si(OEt) 4 are somewhat lpss corrosive to aluminum than is SiCI 4 alone, although some pitting occurs for slow hydrolysis after coating by solutions...humidity (x) 86 A𔃻 determinants of corrosion resistance. The magnesium-silicon- aluminum alloy AA 6061 is generally considered to have good corrosion ... 6061 ), the corrosion resistance exceeded that of the chromate coatings. The feasibilityof the basic approach taken here has been validated. It

  6. Tensiones residuales generadas en acero F-522 por distintos tipos de mecanizado

    Directory of Open Access Journals (Sweden)

    García-Navas, V.

    2005-08-01

    , como en el interior del material. En este trabajo se han medido, mediante difracción de rayos-X, las tensiones residuales en un acero F-522 templado y revenido, generadas por dos procesos de torneado (torneado duro convencional y torneado duro asistido por láser y dos procesos de rectificado (de afino y de producción. Asimismo, se ha estudiado la evolución a lo largo de la profundidad de la fracción volumétrica de austenita retenida, de la microestructura y de nanodureza con el objetivo de relacionar estos resultados con los estados de tensiones obtenidos para cada mecanizado. Se ha observado que el torneado genera fuertes tensiones de tracción en la superficie y el rectificado tensiones de compresión. Inmediatamente, bajo la superficie, el rectificado genera tensiones ligeramente tractivas o nulas, mientras que el torneado genera tensiones fuertemente compresivas. Estos resultados indican que el proceso óptimo de mecanizado (prescindiendo de consideraciones económicas sería aquel que combinase un torneado duro con un ligero rectificado final

  7. Surface modification for corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-06-01

    The raw gas environments that arise from coal gasification have chemical compositions that are low in pO{sub 2} and moderate-to-high in pS{sub 2}. Metallic materials for service in such an environment undergo predominantly sulfidation attack at temperatures of 400 to 700{degree}C. Modification of alloy compositions in bulk can alter the scaling processes and lead to improvements in corrosion resistance, but the benefits can only be attained at temperatures much higher than the service temperatures of the components. Modification of surfaces of structural components by several of the coating techniques examined in this study showed substantial benefit in corrosion resistance when tested in simulated coal gasification environments. The paper presents several examples of surface modification and their corrosion performance.

  8. Electrochemical corrosion of metallic biomaterials.

    Science.gov (United States)

    Pourbaix, M

    1984-05-01

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

  9. Strain Measurement Technology for Corrosion Fatigue Specimen

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Wei-hua; NING; Guang-sheng; ZHANG; Chang-yi; TONG; Zhen-feng; YANG; Wen

    2015-01-01

    Main pipeline is the key component of nuclear power plants(NPPs).Under the first loop water and low-cyclic load condition,the main pipeline may be induced to corrosion fatigue failure.Thus,it’s necessary to test and get the corrosion fatigue property of main pipeline material.During the corrosion fatigue test,the strain

  10. 7 CFR 2902.44 - Corrosion preventatives.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Corrosion preventatives. 2902.44 Section 2902.44... Items § 2902.44 Corrosion preventatives. (a) Definition. Products designed to prevent the deterioration (corrosion) of metals. (b) Minimum biobased content. The preferred procurement product must have a...

  11. 49 CFR 193.2625 - Corrosion protection.

    Science.gov (United States)

    2010-10-01

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

  12. Corrosion-Induced Concrete Cracking Model Considering Corrosion-Filled Paste

    OpenAIRE

    Dong, Jianfeng; Zhao, Yuxi; Wu, Yingyao; Jin, Weiliang

    2016-01-01

    A TCP–TCL model is established to describe the relationship between the thickness of the corrosion-filled paste (CP) and that of the corrosion layer (CL). This model can describe the phenomenon that the corrosion filling in the concrete pores and accumulating at the steel/concrete interface occur synchronously. Based on the TCP–TCL model, a corrosion-induced concrete cracking model, which can quantitatively consider corrosion-filled paste at concrete/steel interface, is proposed. Combined wit...

  13. Corrosion-Inhibitor Efficiency Control: Comparison by Means of Different Portable Corrosion Rate Meters

    OpenAIRE

    Martinez Sierra, Isabel; Andrade Perdrix, Maria del Carmen; Rebolledo Ramos, Nuria; Luo, L; De Schutter, G

    2010-01-01

    Corrosion-inhibiting substances have been applied to suppress corrosion mainly on bare steel, but when corrosion is progressing, suppression can be achieved if anodic and cathodic reactions are avoided, which is not an easy objective, particularly if the bare metal is surrounded by concrete. In the present article, several corrosion inhibitors are studied to identify their inhibition efficiency in concrete. The percentage of reduction of the corrosion rate without and with inhibitor is named ...

  14. Oxygen tension affects lubricin expression in chondrocytes.

    Science.gov (United States)

    Hatta, Taku; Kishimoto, Koshi N; Okuno, Hiroshi; Itoi, Eiji

    2014-10-01

    We assessed the effects of oxygen tension on lubricin expression in bovine chondrocytes and cartilage explants and a role for hypoxia-inducible transcription factor (HIF)-1α in regulating lubricin expression was investigated using a murine chondroprogenitor cell line, ATDC5, and bovine chondrocytes isolated from superficial and middle/deep zones of femoral cartilage. ATDC5 cells and bovine chondrocytes were cultured in micromass under different oxygen tensions (21%, 5%, and 1%). ATDC5 cells and middle/deep zone chondrocytes that initially had low lubricin expression levels were also cultured with or without transforming growth factor (TGF)-β1. Quantitative reverse transcription (RT)-PCR was used to determine lubricin and chondrogenic marker gene mRNA levels and immunohistochemistry was used to assess lubricin protein expression. Explant cartilage plugs cultured under different oxygen tensions were also subjected to immunohistological analysis for lubricin. HIF-1α gene silencing was achieved by electroporatic transfer into ATDC5 cells. A low oxygen tension reduced lubricin gene expression levels in bovine superficial chondrocytes, TGF-β1-treated middle/deep zone chondrocytes, and TGF-β1-treated ATDC5 cells. Lubricin expression in explant cartilage was also suppressed under hypoxia. HIF-1α gene silencing in ATDC5 cells attenuated the lubricin expression response to the oxygen tension. These results corroborate with previous studies that the oxygen tension regulates lubricin gene expression and suggest that HIF-1α plays an important role in this regulation. The normal distribution of lubricin in articular cartilage may be due to the hypoxic oxygen environment of cartilage as it is an avascular tissue. An oxygen tension gradient may be a key factor for engineering cartilage tissue with a layered morphology.

  15. Emergency percutaneous needle decompression for tension pneumoperitoneum

    Directory of Open Access Journals (Sweden)

    Körner Markus

    2011-05-01

    Full Text Available Abstract Background Tension pneumoperitoneum as a complication of iatrogenic bowel perforation during endoscopy is a dramatic condition in which intraperitoneal air under pressure causes hemodynamic and ventilatory compromise. Like tension pneumothorax, urgent intervention is required. Immediate surgical decompression though is not always possible due to the limitations of the preclinical management and sometimes to capacity constraints of medical staff and equipment in the clinic. Methods This is a retrospective analysis of cases of pneumoperitoneum and tension pneumoperitoneum due to iatrogenic bowel perforation. All patients admitted to our surgical department between January 2005 and October 2010 were included. Tension pneumoperitoneum was diagnosed in those patients presenting signs of hemodynamic and ventilatory compromise in addition to abdominal distension. Results Between January 2005 and October 2010 eleven patients with iatrogenic bowel perforation were admitted to our surgical department. The mean time between perforation and admission was 36 ± 14 hrs (range 30 min - 130 hrs, between ER admission and begin of the operation 3 hrs and 15 min ± 47 min (range 60 min - 9 hrs. Three out of eleven patients had clinical signs of tension pneumoperitoneum. In those patients emergency percutaneous needle decompression was performed with a 16G venous catheter. This improved significantly the patients' condition (stabilization of vital signs, reducing jugular vein congestion, bridging the time to the start of the operation. Conclusions Hemodynamical and respiratory compromise in addition to abdominal distension shortly after endoscopy are strongly suggestive of tension pneumoperitoneum due to iatrogenic bowel perforation. This is a rare but life threatening condition and it can be managed in a preclinical and clinical setting with emergency percutaneous needle decompression like tension pneumothorax. Emergency percutaneous decompression is no

  16. Electrochemical Measurement of Atmospheric Corrosion

    Science.gov (United States)

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

    1999-01-01

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

  17. Corrosion performance of structural alloys.

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1999-07-15

    Component reliability and long-term trouble-free performance of structural materials are essential in power-generating and gasification processes that utilize coal as a feedstock. During combustion and conversion of coal, the environments encompass a wide range of oxygen partial pressures, from excess-air conditions in conventional boilers to air-deficient conditions in 10W-NO{sub x} and gasification systems. Apart from the environmental aspects of the effluent from coal combustion and conversion, one concern from the systems standpoint is the aggressiveness of the gaseous/deposit environment toward structural components such as waterwall tubes, steam superheaters, syngas coolers, and hot-gas filters. The corrosion tests in the program described in this paper address the individual and combined effects of oxygen, sulfur, and chlorine on the corrosion response of several ASME-coded and noncoded structural alloys that were exposed to air-deficient and excess-air environments typical of coal-combustion and gasification processes. Data in this paper address the effects of preoxidation on the subsequent corrosion performance of structural materials such as 9Cr-1Mo ferritic steel, Type 347 austenitic stainless steel, Alloys 800, 825, 625, 214, Hastelloy X, and iron aluminide when exposed at 650 C to various mixed-gas environments with and without HCI. Results are presented for scaling kinetics, microstructural characteristics of corrosion products, detailed evaluations of near-surface regions of the exposed specimens, gains in our mechanistic understanding of the roles of S and Cl in the corrosion process, and the effect of preoxidation on subsequent corrosion.

  18. Armor corrosion monitoring of a submarine AC cable

    Energy Technology Data Exchange (ETDEWEB)

    Genesca, J. [Univ. Nacional Autonoma de Mexico (Mexico). Dept. Ingenieria Metalurgica; Perez, T. [Univ. Autonoma de Campeche (Mexico). Programa Corrosion del Golfo de Mexico; Lara, C. [CFE-LAPEM, Irapuato (Mexico)

    1997-12-01

    After the hurricane Gilberto flattened (devastated) Cancun in September 1988, the submarine cables which supplied electricity to Isla Mjueres Island remained very damaged, and it was decided to install the new ones. In 1989, four new submarine cables were installed from Punta Sam, Cancun to Isla Mujeres. Such cables, of nominal tension 34.5 KV, were manufactures with a galvanized steel armor coated with asphalt, and began operation during 1990. The object of this communication is to present the experimental procedure that gave place to the armor corrosion monitoring procedure carried out in this particular case and to compare the results with those obtained on the field. Results of the cathodic protection system applied are also presented.

  19. Exploratory experimental investigations on post-tensioned structural glass beams

    DEFF Research Database (Denmark)

    Louter, C.; Nielsen, Jens Henrik; Belis, J.

    2013-01-01

    This paper discusses two projects on post-tensioned glass beams, performed at EPFL and DTU, respectively. In these projects small scale glass beams (length of 1.5m and 1m) are post-tensioned by means of steel threaded rods tensioned at the beam ends. The purpose of post-tensioning glass beams...

  20. Cyclone reburning retrofit: Corrosion evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Sarv, H.; Paul, L.D. (Babcock and Wilcox Co., New Orleans, LA (USA))

    1991-01-01

    Reburning is an emerging NO{sub x} reducing technology which offers cyclone boiler owners a promising alternative to the more expensive flue gas cleanup techniques. Pilot-scale test results have shown that the corrosive H{sub 2}S gas can evolve during reburn. This can pose a potential problem and concern in retrofits burning high-sulfur Illinois coals. This research program is intended to assess tube corrosion under simulated reburning conditions (temperature, stoichiometry, and H{sub 2}S concentration). Performance of existing carbon steel as well as other alloys will be tested and compared. 1 fig.

  1. Cyclone reburning retrofit: Corrosion evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Farzan, H.; Paul, L.D. (Babcock and Wilcox Co., New Orleans, LA (USA))

    1990-01-01

    Reburning is an emerging NO{sub x} reducing technology which offers cyclone boiler owners a promising alternative to the more expensive flue gas cleanup techniques. Pilot-scale test results have shown that the corrosive H{sub 2}S gas can evolve during reburn. This can pose a potential problem and concern in retrofits burning high-sulfur Illinois coals. This research program is intended to assess tube corrosion under simulated reburning conditions (temperature, stoichiometry, and H{sub 2}S concentration). Performance of existing carbon steel as well as other alloys will be tested and compared. 1 fig.

  2. Corrosion Reliability of Electronic Systems

    DEFF Research Database (Denmark)

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

    2008-01-01

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

  3. Microbial Influenced Corrosion (MIC) Study

    Science.gov (United States)

    2012-05-23

    low lying areas breaks down protective coating system and causes structural corrosion , • Water and organic/inorganic nutrients BUSINESS SENSITIVE...Chemical disinfection (T.O 1-1-8 and T.O 1-1-691) • Biocidal rinses and coatings • Biocidal Corrosion Preventative Compounds or CPCs BUSINESS...Type: H    Proprietary  Coating  w/ Silver  Inhibitor   Non‐Chrome Treatment + Mg‐Rich  Primer  Coupon Type: I    Prekote® (Pantheon Chemical) N/A

  4. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

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

  5. Corrosive effects of hvdc transmission

    Energy Technology Data Exchange (ETDEWEB)

    Cornwell, F.E.; Backstrom, T.E.

    1966-02-01

    Field tests using ac transmission lines for introduction of direct current into the earth at widely separated points are described. One test circuit was between a Tracy pumping plant and a Shasta power plant in California, and two others were in the Hoover power plant area. Evaluation of the effects of such ground currents on corrosion of buried metalwork was a primary aim of the tests. Potential gradients, pipe-to-soil potentials, and soil resistivities are discussed in detail. Estimates are made of the distances from ehv dc terminal installations within which corrosion prevention procedures may become necessary.

  6. Coatings for improved corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1992-05-01

    Several coating approaches are being developed to resist attack in coal-fired environments and thereby minimize corrosion of underlying substrate alloys and extend the time for onset of breakaway corrosion. In general, coating systems can be classified as either diffusion or overlay type, which are distinguished principally by the method of deposition and the structure of the resultant coating-substrate bond. The coating techniques examined are pack cementation, electrospark deposition, physical and chemical vapor deposition, plasma spray, and ion implantation. In addition, ceramic coatings are used in some applications.

  7. Tension Distribution in a Tendon-Driven Robotic Finger

    Science.gov (United States)

    Abdallah, Muhammad E. (Inventor); Platt, Robert (Inventor); Wampler, II, Charles W. (Inventor)

    2013-01-01

    A method is provided for distributing tension among tendons of a tendon-driven finger in a robotic system, wherein the finger characterized by n degrees of freedom and n+1 tendons. The method includes determining a maximum functional tension and a minimum functional tension of each tendon of the finger, and then using a controller to distribute tension among the tendons, such that each tendon is assigned a tension value less than the maximum functional tension and greater than or equal to the minimum functional tension. The method satisfies the minimum functional tension while minimizing the internal tension in the robotic system, and satisfies the maximum functional tension without introducing a coupled disturbance to the joint torques. A robotic system includes a robot having at least one tendon-driven finger characterized by n degrees of freedom and n+1 tendons, and a controller having an algorithm for controlling the tendons as set forth above.

  8. INTERFACIAL DEBONDING OF COATED-FIBER-REINFORCED COMPOSITES UNDER TENSION-TENSION CYCLIC LOADING

    Institute of Scientific and Technical Information of China (English)

    Shi Zhifei; Zhou Limin

    2000-01-01

    A new degradation function of the friction coefficient is used. Based on the double shear-lag model and Paris formula, the interfacial damage of coated fiber-reinforced composites under tension-tension cyclic loading is studied. The effects of strength and thickness of the coating materials on the debond stress, debond rate as well as debond length are simulated.

  9. A Multifunctional Coating for Autonomous Corrosion Control

    Science.gov (United States)

    Calle, L. M.; Hintze, P. E.; Li, W.; Buhrow, J. W.; Jolley, S. T.

    2011-01-01

    This slide presentation reviews the effects of corrosion on various structures at the Kennedy Space Center, and the work to discover a corrosion control coating that will be autonomous and will indicate corrosion at an early point in the process. Kennedy Space Center has many environmental conditions that are corrosive: ocean salt spray, heat, humidity, sunlight and acidic exhaust from the Solid Rocket Boosters (SRBs). Presented is a chart which shows the corrosion rates of carbon steel at various locations. KSC has the highest corrosion rates with 42.0 mils/yr, leading the next highest Galeta Point Beach, in the Panama Canal Zone with 27 mils/yr corrosion. A chart shows the changes in corrosion rate with the distance from the ocean. The three types of corrosion protective coatings are described: barrier (passive), Barrier plus active corrosion inhibiting components, and smart. A smart coating will detect and respond actively to changes in its environment in a functional and predictable manner and is capable of adapting its properties dynamically. The smart coating uses microcapsules, particles or liquid drops coated in polymers, that can detect and control the corrosion caused by the environment. The mechanism for a pH sensitive microcapsule and the hydrophobic core microcapsule are demonstrated and the chemistry is reviewed. When corrosion begins, the microcapsule will release the contents of the core (indicator, inhibitor, and self healing agent) in close proximity to the corrosion. The response to a pH increase is demonstrated by a series of pictures that show the breakdown of the microcapsule and the contents release. An example of bolt corrosion is used, as an example of corrosion in places that are difficult to ascertain. A comparison of various coating systems is shown.

  10. Transcutaneous oxygen tension in imminent foot gangrene

    DEFF Research Database (Denmark)

    Tønnesen, K H

    1978-01-01

    Transcutaneous oxygen tension at 44 degree C and maximal isotope clearance (90m Tc-pretechnetate + histramine) just proximal to the 1st toe and systolic toe blood pressure (strain gauge) were studied on a tilt table in patients with various degrees of obstructive arteriosclerotic disease. In legs...... the arterioles into the tissue sink and counter current gas shunting. The hypoxia in spite of a positive perfusion pressure up to 50 mmHg explains our experience that ischemic ulcers in feet such low pressures never heal.......Transcutaneous oxygen tension at 44 degree C and maximal isotope clearance (90m Tc-pretechnetate + histramine) just proximal to the 1st toe and systolic toe blood pressure (strain gauge) were studied on a tilt table in patients with various degrees of obstructive arteriosclerotic disease. In legs...... with moderate obstruction, the oxygen tension reached zero at a toe systolic blood pressure of 5--10 mmHg (tilt toe up) and reached arterial oxygen tension at about 50 to 70 mmHg (tilt toe down). In legs withsevere arterial obstruction and ischaemic rest pain, oxygen tension rose from zero not before systolic...

  11. Methodology for the accelerated simulation of the deterioration that by atmospheric corrosion appears in electronic equipment; Metodologia para la simulacion acelerada del deterioro que por corrosion atmosferica se presenta en equipo electronico

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz Prado, A.; Schouwenaars, R.; Cerrud Sanchez, S.M. [Facultad de Ingenieria, UNAM, Mexico, D.F. (Mexico)

    2002-12-01

    The corrosion resistance of systems and electronic parts which are designed to work in atmospheric conditions have been tested for decades; some of these methods were the Cyclic Humidity Test, Field Tests and Salt Spray (Fog) Testing, the latter was one of the most popular methods. However, the salt spray test and most of the other existing methods do not show strong relationships with the real conditions of service. For this reason, it is necessary to develop appropriated methods and equipment for the accelerated simulation of real atmospheric corrosion phenomena. This article seeks to demonstrate the need to develop a test and the necessary equipment to reproduce the damage in electronic systems and equipment by atmospheric corrosion. [Spanish] Para la evaluacion de la resistencia a la corrosion de sistemas y equipo electronico que trabajaran bajo condiciones de deterioro generadas por el medio ambiente, se han aplicado una serie de ensayos, donde el mas popular es el de camara de niebla salina. Sin embargo, este y otros que se han elaborado para tal efecto no tienen ninguna relacion con las condiciones reales de servicio, por lo que es necesario un metodo de evaluacion que permita simular de forma acelerada los fenomenos de deterioro por efectos ambientales. Este articulo pretende demostrar la necesidad de desarrollar una prueba, que en forma acelerada, reproduzca el dano que sufre el material por efecto de la atmosfera; el cual se orienta a la evaluacion de equipo electrico y electronico.

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

    Directory of Open Access Journals (Sweden)

    Hwee Ling Lim

    2012-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2000-01-28

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

  14. Atmospheric corrosion sensor based on strain measurement

    Science.gov (United States)

    Kasai, Naoya; Hiroki, Masatoshi; Yamada, Toshirou; Kihira, Hiroshi; Matsuoka, Kazumi; Kuriyama, Yukihisa; Okazaki, Shinji

    2017-01-01

    In this paper, an in situ atmospheric corrosion sensor based on strain measurement is discussed. The theoretical background for measuring the reduction in thickness of low carbon steel is also presented. Based on the theoretical considerations, a test piece and apparatus for an atmospheric corrosion sensor were designed. Furthermore, in a dry–wet cyclic accelerated exposure experiment, the measured strain indicated thinning of the test piece, although the corrosion product generated on the surface of the test piece affected the results. The atmospheric corrosion sensor would be effective for evaluating atmospheric corrosion of many types of infrastructure.

  15. Nodular Corrosion Characteristics of Zirconium Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Gil; Jeong, Y. H.; Park, S. Y.; Lee, D. J

    2003-01-15

    This study was reported the effect of the nodular corrosion on the nuclear reactor environmental along with metallurgical influence, also suggested experimental scheme related to evaluate nodular corrosion characteristics of Zr-1 Nb alloy. Remedial strategies against the nodular corrosion should firstly develop plan to assess the effect of the water quality condition (Oxygen, Hydrogen) as well as the boiling on the nodular corrosion, secondarily establish plan to control heat treatment process to keep a good resistance on nodular corrosion in Zr-1Nb alloy as former western reactor did.

  16. Quaternary active tectonic structures in the offshore Bajo Segura basin (SE Iberian Peninsula - Mediterranean Sea)

    Science.gov (United States)

    Perea, H.; Gràcia, E.; Alfaro, P.; Bartolomé, R.; Lo Iacono, C.; Moreno, X.; Masana, E.; Event-Shelf Team

    2012-10-01

    The Bajo Segura fault zone (BSFZ) is the northern terminal splay of the Eastern Betic shear zone (EBSZ), a large left-lateral strike-slip fault system of sigmoid geometry stretching more than 450 km from Alicante to Almería. The BSFZ extends from the onshore Bajo Segura basin further into the Mediterranean Sea and shows a moderate instrumental seismic activity characterized by small earthquakes. Nevertheless, the zone was affected by large historical earthquakes of which the largest was the 1829 Torrevieja earthquake (IEMS98 X). The onshore area of the BSFZ is marked by active transpressive structures (faults and folds), whereas the offshore area has been scarcely explored from the tectonic point of view. During the EVENT-SHELF cruise, a total of 10 high-resolution single-channel seismic sparker profiles were obtained along and across the offshore Bajo Segura basin. Analysis of these profiles resulted in (a) the identification of 6 Quaternary seismo-stratigraphic units bounded by five horizons corresponding to regional erosional surfaces related to global sea level lowstands; and (b) the mapping of the active sub-seafloor structures and their correlation with those described onshore. Moreover, the results suggest that the Bajo Segura blind thrust fault or the Torrevieja left-lateral strike-slip fault, with prolongation offshore, could be considered as the source of the 1829 Torrevieja earthquake. These data improve our understanding of present deformation along the BSFZ and provide new insights into the seismic hazard in the area.

  17. Elastic properties and mechanical tension of graphene

    Science.gov (United States)

    Ramírez, R.; Herrero, C. P.

    2017-01-01

    Room-temperature simulations of graphene have been performed as a function of the mechanical tension of the layer. Finite-size effects are accurately reproduced by an acoustic dispersion law for the out-of-plane vibrations that, in the long-wave limit, behaves as ρ ω2=σ k2+κ k4 . The fluctuation tension σ is finite (˜0.1 N/m) even when the external mechanical tension vanishes. Transverse vibrations imply a duplicity in the definition of the elastic constants of the layer, as observables related to the real area of the surface may differ from those related to the in-plane projected area. This duplicity explains the variability of experimental data on the Young modulus of graphene based on electron spectroscopy, interferometric profilometry, and indentation experiments.

  18. Tension Stiffened and Tendon Actuated Manipulator

    Science.gov (United States)

    Doggett, William R. (Inventor); Dorsey, John T. (Inventor); Ganoe, George G. (Inventor); King, Bruce D. (Inventor); Jones, Thomas C. (Inventor); Mercer, Charles D. (Inventor); Corbin, Cole K. (Inventor)

    2015-01-01

    A tension stiffened and tendon actuated manipulator is provided performing robotic-like movements when acquiring a payload. The manipulator design can be adapted for use in-space, lunar or other planetary installations as it is readily configurable for acquiring and precisely manipulating a payload in both a zero-g environment and in an environment with a gravity field. The manipulator includes a plurality of link arms, a hinge connecting adjacent link arms together to allow the adjacent link arms to rotate relative to each other and a cable actuation and tensioning system provided between adjacent link arms. The cable actuation and tensioning system includes a spreader arm and a plurality of driven and non-driven elements attached to the link arms and the spreader arm. At least one cable is routed around the driven and non-driven elements for actuating the hinge.

  19. Cosmological Spacetimes from Negative Tension Brane Backgrounds

    CERN Document Server

    Burgess, C P; Rey, S J; Tasinato, G

    2002-01-01

    We put forward a viable nonsingular cosmology emerging out of negative-tension branes. The cosmology is based on a general class of solutions in Einstein-dilaton-Maxwell theory, presented in {\\tt hep-th/0106120}. We argue that solutions with hyperbolic or planar symmetry describe gravitational interactions due to a pair of negative-tension $q$-branes. These spacetimes are static near each brane, but become time-dependent and expanding at late times -- in some cases asymptotically approaching flat space. We interpret this expansion as being the spacetime's response to the branes presence. The time-dependent regions provide explicit realizations of cosmological spacetimes having past horizons without naked past singularities, and the past horizons are reminiscent of the S-brane solutions. We prove that the singularities in the static regions are repulsive to timelike geodesics, extract a cosmological `bounce' interpretation, compute the explicit charge and tension of the branes, analyse the classical stability ...

  20. Statistical Mechanics of Multilayer Sorption: Surface Tension.

    Science.gov (United States)

    Wexler, Anthony S; Dutcher, Cari S

    2013-05-16

    Mathematical models of surface tension as a function of solute concentration are needed for predicting the behavior of surface processes relevant to the environment, biology, and industry. Current aqueous surface tension-activity models capture either solutions of electrolytes or those of nonelectrolytes, but a single equation has not yet been found that represents both over the full range of compositions. In prior work, we developed an accurate model of the activity-concentration relationship in solutions over the full range of compositions by extending the BET (Brunauer, Emmett, Teller) and GAB (Guggenheim, Anderson, de Boer) isotherms to multiple monolayers of solvent molecules sorbed to solutes. Here, we employ similar statistical mechanical tools to develop a simple equation for the surface tension-activity relationship that differs remarkably from prior formulations in that it (1) works equally well for nonelectrolyte and electrolyte solutes and (2) is accurate over the full range of concentrations from pure solvent to pure solute.

  1. Surface tension effects in breaking wave noise.

    Science.gov (United States)

    Deane, Grant B

    2012-08-01

    The role of surface active materials in the sea surface microlayer on the production of underwater noise by breaking waves is considered. Wave noise is assumed to be generated by bubbles formed within actively breaking whitecaps, driven into breathing mode oscillation at the moment of their formation by non-equilibrium, surface tension forces. Two significant effects associated with surface tension are identified-a reduction in low frequency noise (bubbles by fluid turbulence within the whitecap and a reduction in overall noise level due to a decrease in the excitation amplitude of bubbles associated with reduced surface tension. The impact of the latter effect on the accuracy of Weather Observations Through Ambient Noise estimates of wind speed is assessed and generally found to be less than ±1 m s(-1) for wind speeds less than 10 m s(-1) and typical values of surfactant film pressure within sea slicks.

  2. Fatigue In Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Uhre; Hoffmeyer, Preben;

    2004-01-01

    mechanism and a mechanism connected to damage introduced in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In arder to test the predictive validity of the result from the small tension specimens, fatigue experiments......Traditionally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...

  3. Fatigue in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben;

    1999-01-01

    mechanism and a mechanism connected to damage introduce in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In order to test the predictive validity of the result from the small tension specimens, fatigue experiments......Traditinally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...

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

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

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

  5. The dual role of microbes in corrosion.

    Science.gov (United States)

    Kip, Nardy; van Veen, Johannes A

    2015-03-01

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

  6. The dual role of microbes in corrosion

    Science.gov (United States)

    Kip, Nardy; van Veen, Johannes A

    2015-01-01

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

  7. Corrosion resistant metallic bipolar plate

    Science.gov (United States)

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  8. CORROSION INHIBITOR FOR CARBON STEELS

    African Journals Online (AJOL)

    corrosion inhibitor for carbon steel in 3% ac]neon.s' NaCl solution (pH 6) ... compared to stainless steels (Buchweishaija & Hagen 1997). Organic compounds are ... resistant dust for break and clutch linings, wood binders and mould (Gedam.

  9. Encapsulated Multifunction Corrosion Inhibitive Primer.

    Science.gov (United States)

    1983-11-01

    Tec #19 (alkaline detergent), scrubbed vigorously with cheese cloth, then perform R.I.A. drop test for cleanliness (ASTM 7.1.6.22) (Turco Air Tec...Systems, DOE/NASA TM-78180 (1978). 39. Gouda , V.K. and Shater, M.A., Corrosion Sci. 15 199 (1975). 40. Controlled release, Pesticide Symposium 41

  10. Corrosion inhibition for distillation apparatus

    Science.gov (United States)

    Baumert, Kenneth L.; Sagues, Alberto A.; Davis, Burtron H.; Schweighardt, Frank K.

    1985-01-01

    Tower material corrosion in an atmospheric or sub-atmospheric distillation tower in a coal liquefaction process is reduced or eliminated by subjecting chloride-containing tray contents to an appropriate ion-exchange resin to remove chloride from such tray contents materials.

  11. CORROSION RESISTANT JACKETED METAL BODY

    Science.gov (United States)

    Brugmann, E.W.

    1958-08-26

    Reactor faul elements of the elongated cylindrical type which are jacketed in a corrosion resistant material are described. Each feel element is comprised of a plurality of jacketed cylinders of fissionable material in end to end abutting relationship, the jackets being welded together at their adjoining ends to retain the individual segments together and seat the interior of the jackets.

  12. Evolutionary Computation Techniques for Predicting Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Amine Marref

    2013-01-01

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

  13. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  14. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

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

    2005-01-01

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

  15. Effect of corrosion on flexural bond strength

    Directory of Open Access Journals (Sweden)

    Akshatha Shetty

    2014-09-01

    Full Text Available Corrosion is one of the main causes affecting durability of structures. Corrosion effects on structures cannot be ignored and replaced. To understand the performance of structures there is a need to study the rate at which different corrosion levels occur. Hence the present investigation has been taken up to study the behaviour of NBS (National Bureau of Standard beam specimens made up of Ordinary Portland Cement (OPC and Portland Pozzolona Cement (PPC concrete matrix were subjected to accelerated corrosion for different corrosion levels of 2.5 % to 10 % at 2.5 % interval. Results are compared with those for control beam specimen. It is observed that bond stress value decreases with the increase in corrosion levels. Also corrosion leads to the decline of load carrying capacity.

  16. High Temperature Corrosion on Biodust Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi

    The high content of alkali metals and chlorine in biomass gives rise to fouling/slagging and corrosion of heat exchange components, such as superheaters, in biomass fired power plants. Increasing the lifetime of these components, and in addition, preventing unwarranted plant shutdowns due...... to their failure, requires understanding of the complex corrosion mechanisms, as well as development of materials that are resistant to corrosion under biomass firing conditions, thereby motivating the current work. To understand the mechanisms of corrosion attack, comprehensive analysis of corrosion products...... was necessary. In the present work, two complementary methodologies based on analysis of cross sections and plan views were applied to achieve comprehensive characterization of corrosion products. The suitability of these methods for both laboratory scale and full scale corrosion investigations was demonstrated...

  17. Surface-tension properties of hyaluronic Acid.

    Science.gov (United States)

    Knepper, P A; Covici, S; Fadel, J R; Mayanil, C S; Ritch, R

    1995-06-01

    The maintenance of flow channels in the trabecular meshwork is dependent, in part, on the patency of the trabecular spaces. Because the amount of hyaluronic acid decreases in the trabecular meshwork of patients with primary open-angle glaucoma, a change in surface tension may be one of the effects of hyaluronic acid on aqueous outflow. The surface-active properties of hyaluronic acid (concentration of 0.156-2.5 mg/ml; molecular weights of 100,000, 500,000, and 4,000,000) in deionized water, Ringer's lactate, Ringer's lactate plus 0.06 mg/ml bovine serum albumin, and mock aqueous solution were tested using the drop volume method. At a hyaluronic acid concentration of 0.312 mg/ml, surface tension decreased; at higher concentrations, a further decrease in surface tension was observed. In the presence of Ringer's lactate, the 100,000-MW hyaluronic acid was more active than the 4,000,000-MW hyaluronic acid. In the presence of Ringer's lactate plus bovine serum albumin or mock aqueous solution, the influence of surface tension of the 100,000-MW hyaluronic acid was moderated: with lower hyaluronic acid concentrations, the decline in surface tension was more than with Ringer's lactate, but with higher hyaluronic acid concentrations, the decline in surface tension was less than with Ringer's lactate. At high concentration, hyaluronic acid behaves like a non-Newtonian fluid, becomes more viscous, and may act to "seal" the trabecular space. The results of this study indicate that hyaluronic acid possesses surface-active properties, which is just one of several properties of hyaluronic acid that may influence aqueous outflow resistance.

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

    Science.gov (United States)

    Calle, Luz Marina

    2015-01-01

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

  19. Students' difficulties with tension in massless strings

    Science.gov (United States)

    Flores-García, S.; Alfaro-Avena, L. L.; Chávez-Pierce, J. E.; Luna-González, J.; González-Quezada, M. D.

    2010-12-01

    Many students enrolled in introductory mechanics courses have difficulties with understanding the concept of static equilibrium. Some of these difficulties are related to the concept of force in the context of tension in massless strings. We identify three kinds of misconceptions: Students' beliefs that the angle of the string and proximity to the object are related to the tension. Students also use incorrect compensation arguments to reason about situations where both the angle and proximity change simultaneously. These difficulties were identified during investigations conducted in laboratory and lecture sessions at three universities in the United States and Mexico.

  20. Evaluación del empleo de aceros de bajo contenido de carbono en la fabricación del cuerpo de cilindros oleohidráulicos. // Low carbon steel evaluation for oleohydraulic cylinders manufacturing.

    Directory of Open Access Journals (Sweden)

    V. Gómez Rodríguez

    2003-05-01

    Full Text Available En el trabajo se realiza una evaluación del empleo de aceros de bajo contenido de carbono en la fabricación del cuerpo decilindros oleohidráulicos de producción nacional. Se estudia la influencia del cambio de material en la calidad superficial,la resistencia al desgaste y el comportamiento desde el punto de vista de la corrosión.Palabras claves: Cilindros oleohidráulicos, resistencia superficial, corrosión, acero._________________________________________________________________________________Abstract.In this paper, an evaluation of the use of low carbon steel used to manufacture the hydraulic homemade cylinders body iscarried out. The influence of change of material in surface quality, the wear resistance and the behaviour from the corrosionpoint of view, are studied.Key words: Oleohydraulic cylinders, superficial strength, corrosion, steel.

  1. Titanium corrosion in alkaline hydrogen peroxide environments

    Science.gov (United States)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  2. A progressive reduce tension method to fabricate Bradbury-Nielsen gates with uniform tension

    CERN Document Server

    Kai, Ni; Zhou, Yu

    2015-01-01

    Bradbury-Nielsen gates (BNG) which consist of two interleaved and electrically isolated sets of wires can be used to modulate the beams of charged particles, particularly ion beams in mass spectrometry and ion mobility spectrometry. The wires of BNG with uniform tension is critical to make sure the BNG work reliable and robust. In our previous work, we have analyzed the problem of wires tension non-uniform that exists in the traditional sequentially winding methods when the metal wire's elastic modulus is much larger than insulations substrate's and developed a template-based transfer method to solve this problem. In this study, we proposed a progressive reduce tension method which does not need template to fabricate BNG with uniform tension. First input the initial parameters to calculate the final progressive reduce tension sequence (FA(i)) through program; then sequentially adjust the weight set according to FA(i) to construct a BNG with uniform tension wires through a home-built device. Wires tension non-...

  3. Corrosion inhibition of a hygroscopic inorganic dust-depressor

    Institute of Scientific and Technical Information of China (English)

    Longzhe Jin; Lu Wang; Dongke Chen

    2006-01-01

    Metallic corrosion is a serious problem in the application of a hygroscopic inorganic dust-depressor. The basic characteristics of a hygroscopic inorganic dust-depressor and its corrosivity, corrosion mechanism, as well as the principle of corrosion inhibition were analyzed. The static mass-loss test was carried out to investigate the corrosion behavior and the effect of the dustdepressor. The static corrosion rates of steel specimens were measured in six different corrosion inhibitor solutions of the dustdepressor, and the suitable corrosion inhibitors for the dust-depressor to reduce the corrosivity were found out.

  4. Microencapsulation Technology for Corrosion Mitigation by Smart Coatings

    Science.gov (United States)

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

    2011-01-01

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

  5. Electrochemical characterisation speeds up prediction of corrosion behaviour

    Energy Technology Data Exchange (ETDEWEB)

    Schuring, E.W.; Hooijmans, J.W. [ECN Environment and Energy Engineering, Petten (Netherlands)

    2013-04-15

    The contents of this presentation show the following elements: Introduction; Corrosion in real life; Why Electrochemical characterisation of corrosion; Applications (corrosion resistance coatings, corrosion behaviour (brazed) joints); Available electrochemical corrosion techniques; Standards; Conclusions. In the Conclusions the corrosion screening method is summarized: ECN method fast; within 1h -1 week results depending on test method; Fast pre-selection of promising materials/combinations (cost savings); Determining of corrosion initiation; Determination of corrosion mechanisms and propagation; Life time predictions possible; Strong combination with metallographic post-investigation; Ranking materials / constructions for corrosion performance.

  6. Standard Practice for Making and Using U-Bend Stress-Corrosion Test Specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2009-01-01

    1.1 This practice covers procedures for making and using U-bend specimens for the evaluation of stress-corrosion cracking in metals. The U-bend specimen is generally a rectangular strip which is bent 180° around a predetermined radius and maintained in this constant strain condition during the stress-corrosion test. Bends slightly less than or greater than 180° are sometimes used. Typical U-bend configurations showing several different methods of maintaining the applied stress are shown in Fig. 1. 1.2 U-bend specimens usually contain both elastic and plastic strain. In some cases (for example, very thin sheet or small diameter wire) it is possible to form a U-bend and produce only elastic strain. However, bent-beam (Practice G 39 or direct tension (Practice G 49)) specimens are normally used to study stress-corrosion cracking of strip or sheet under elastic strain only. 1.3 This practice is concerned only with the test specimen and not the environmental aspects of stress-corrosion testing which are discus...

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

    Directory of Open Access Journals (Sweden)

    Ayman M. Atta

    2015-06-01

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

  8. Worldsheet electromagnetism and the superstring tension

    Energy Technology Data Exchange (ETDEWEB)

    Townsend, P.K. (DAMTP, Univ. Cambridge (United Kingdom))

    1992-03-05

    A superstring action, invariant under the symmetries corresponding to a free differential N=1 superalgebra, is constructed. Its worldsheet fields include an electromagnetic gauge potential. Its equations of motion are those of the Green-Schwarz superstring but with the string tension given by the circulation of the worldsheet electric field around the string. (orig.).

  9. Tension Tests On Bored Piles In Sand

    DEFF Research Database (Denmark)

    Krabbenhøft, Sven; Clausen, Johan; Damkilde, Lars

    2006-01-01

    The lengths of the bored piles varied from 2 m to 6 m and all were of a diameter of 140 mm. The piles were tested to failure in tension and the load-displacement relations were recorded. The investigation has shown pronounced differences between the load bearing capacities obtained by different...

  10. Surface tension of evaporating nanofluid droplets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Ruey-Hung [Univ. of Central Florida, Orlando, FL (United States); Phuoc, Tran X. [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States); Martello, Donald [National Energy Technology Lab. (NETL), Pittsburgh, PA, (United States)

    2011-05-01

    Measurements of nanofluid surface tension were made using the pendant droplet method. Three different types of nanoparticles were used - laponite, silver and Fe2O3 - with de-ionized water (DW) as the base fluid. The reported results focus on the following categories; (1) because some nanoparticles require surfactants to form stable colloids, the individual effects of the surfactant and the particles were investigated; (2) due to evaporation of the pendant droplet, the particle concentration increases, affecting the apparent surface tension; (3) because of the evaporation process, a hysteresis was found where the evaporating droplet can only achieve lower values of surface tension than that of nanofluids at the same prepared concentrations: and (4) the Stefan equation relating the apparent surface tension and heat of evaporation was found to be inapplicable for nanofluids investigated. Comparisons with findings for sessile droplets are also discussed, pointing to additional effects of nanoparticles other than the non-equilibrium evaporation process.

  11. Tension in Chemistry and Its Contents

    Science.gov (United States)

    Hoffmann, Roald

    2015-01-01

    This article makes a case for a positive role of tension in the creative process in chemistry. I begin with an argument that there is an inherent tension in what makes molecules interesting—their positioning along various polar axes. One of these, the age-old differentiation between useful (to society and for personal profit) commercialization and pure understanding of molecules and their reactions is characteristic. The question of whether there are any bad molecules then leads me to ethical concerns in chemistry, and a particular working out of these in interactions of chemists in the Middle East. An analysis is made of the special tensions involved in publishing, especially in citation ethics; chemists publish a lot, so this is situation ethics worked out on a daily basis. I then find in the literature of psychology good evidence for the positive value of moderate stress in stimulating creativity. It is obvious that too much tension leads to distress, and there are some institutional aspects of chemistry that do not come out well here. But all in all, the dynamic middle is alive, and it leads to good new science. PMID:26155730

  12. Regulation of Cellular Tension in Adherent Cells

    Science.gov (United States)

    Oakes, Patrick

    2013-03-01

    Cells generate stress on their surrounding extracellular matrix (ECM) via myosin II motor generated forces which are transmitted through the actin cytoskeleton. The mechanisms in the cell which regulate the magnitude and spatial distribution of these stresses, however, remain unknown. Consistent with previous reports, we find that the total magnitude of traction force exerted on the ECM scales with cell size. Such scaling is observed across numerous cell types and reflects an inherent cellular tension determined by the level of myosin II activity. Surprisingly, while stiffness modulates the cellular spread area, we find this scaling relationship to be independent of ECM stiffness. To identify the biophysical mechanisms regulating the generation of tension, we utilize micro-patterning to isolate cell spread area from cell geometry and to spatially control the distribution of stress on the ECM. We find that traction stress magnitude is dependent on the local curvature of the cell. Changes in cell geometry result in a redistribution of local stresses, but little change in the total stress applied to the ECM. Finally, for a constant geometry, we find that both the total stress and the average stress exerted on the ECM increase with cell area. Together these data suggest that the cell can be modeled as a uniformly contracting mesh, where the magnitude of tension is regulated by the cell spread area, and the distribution of tension is regulated by local geometry.

  13. Study of branes with variable tension

    CERN Document Server

    Aros, Rodrigo

    2016-01-01

    In this work we study a brane world model with variable tension which gives rise to four dimensional cosmologies. The brane worlds obtained correspond to E\\"{o}tv\\"{o}s branes whose (internal) geometry can be casted as either a four dimensional (A)dS$_{4}$ or a standard radiation period cosmology. The matter dominated period is discussed as well.

  14. Normal tension glaucoma and Alzheimer disease

    DEFF Research Database (Denmark)

    Bach-Holm, Daniella; Kessing, Svend Vedel; Mogensen, Ulla

    2012-01-01

    PURPOSE: To investigate whether normal tension glaucoma (NTG) is associated with increased risk of developing dementia/Alzheimer disease (AD). METHODS: A total of 69 patients with NTG were identified in the case note files in the Glaucoma Clinic, University Hospital of Copenhagen (Rigshospitalet...

  15. Tension in Chemistry and Its Contents.

    Science.gov (United States)

    Hoffmann, Roald

    2015-01-01

    This article makes a case for a positive role of tension in the creative process in chemistry. I begin with an argument that there is an inherent tension in what makes molecules interesting--their positioning along various polar axes. One of these, the age-old differentiation between useful (to society and for personal profit) commercialization and pure understanding of molecules and their reactions is characteristic. The question of whether there are any bad molecules then leads me to ethical concerns in chemistry, and a particular working out of these in interactions of chemists in the Middle East. An analysis is made of the special tensions involved in publishing, especially in citation ethics; chemists publish a lot, so this is situation ethics worked out on a daily basis. I then find in the literature of psychology good evidence for the positive value of moderate stress in stimulating creativity. It is obvious that too much tension leads to distress, and there are some institutional aspects of chemistry that do not come out well here. But all in all, the dynamic middle is alive, and it leads to good new science.

  16. Inclusion and Participation: Working with the Tensions

    Directory of Open Access Journals (Sweden)

    Gideon Calder

    2011-12-01

    Full Text Available Democracy is crucially about inclusion: a theory of democracy must account for who is to be included in the democratic process, how, and on what terms. Inclusion, if conceived democratically, is fraught with tensions. This article identifies three such tensions, arising respectively in: (i the inauguration of the democratic public; (ii enabling equal participation; and (iii the relationship between instrumental and non-instrumental accounts of democracy’s value. In each case, I argue, rather than seeking somehow to dissolve or avoid such tensions, theories of democracy should allow us to live with their implications reflexively: to work with them. Such tensions are counter-democratic to the extent that they derail what Nancy Fraser calls “participatory parity,” under which citizens count as “full partners in social interaction.” But the extent to which they do this is not itself dependent on points of paradox in the very idea of inclusion. Such parity relies on complex factors, social and economic, which democratic institutions and procedures will not by themselves address. To achieve full democratic inclusion we must already have addressed such factors; no account of democracy itself, however finely-tuned, will do this.

  17. Dynamic Surface Tensions of Fluorous Surfactant Solutions

    Institute of Scientific and Technical Information of China (English)

    高艳安; 侯万国; 王仲妮; 李干佐; 韩布兴; 张高勇; 吕锋锋

    2005-01-01

    Dynamic surface properties of aqueous solutions of cationic fluorous surfactant CF3CF2CF20(CF(CF3)CF2O)2CF(CF3)CONH(CHE)3N+(C2H5)2CH3I- (abbrev. FC-4 ) were reported. The critical micelle concentration (cmc)(3.6×10-5 mol/L) and equilibdum surface tensions γeq were measured by Krtlss K12 tension apparatus. Dynamic surface tension γ(t) was measured in the range of 15 ms to 200 s using the MBP tensiometer. The surface excess Γ,as a function of concentration, was obtained from equilibrium tensiometry using the Gibbs equation. Data from these experiments were combined to analyze the γ(t) decays according to the asymptotic Ward and Tordai equation.The results show that at the initial adsorption stage, the dynamic surface tension data were all consistent with this diffusion-controlled mechanism, and at the end of the adsorption process, there were some evidences for an adsorption barrier, suggesting a mixed diffusion-controlled adsorption mechanism. Using measured quantities, the barrier strength was estimated as between 25 and 35 kJ/mol at 25℃. The surface pressure plays an important role in contributing to the barrier.

  18. Tension and relaxation in the individual.

    Science.gov (United States)

    Newbury, C R

    1979-06-01

    Increasing materialism in society is resulting in more wide spread nervous tension in all age groups. While some degree of nervous tension is necessary in everyday living, its adverse effects require that we must learn to bring it under control. Total tension is shown to have two components: a controllable element arising from factors in the environment and the inbuilt uncontrollable residue which is basic in the individual temperament. The effects of excessive or uncontrolled stress can be classified as 1) emotional reactions such as neurotic behaviour (anxiety hypochondria, hysteria, phobia, depression obsessions and compulsions) or psychotic behaviour and 2) psychosomatic reactions (nervous asthma, headache, insomnia, heart attack). Nervous energy can be wastefully expended by such factors as loss of temper, wrong attitudes to work, job frustration and marital strains. Relaxation is the only positive way to control undesirable nervous tension and its techniques require to be learned. A number of techniques (progressive relaxation, differential relaxation, hypnosis, the use of biofeedback, Yoga and Transcendental Meditation) are described and their application to dental practice is discussed.

  19. INTERNAL CORROSION MONITORING IN OFFSHORE PLATFORMS

    Directory of Open Access Journals (Sweden)

    Fernando Benedicto Mainier

    2008-08-01

    Full Text Available Corrosion is one of the main causes of failures in equipment and pipes in off-shore oil production. These failures harm the process, slow the production operational chronogram, and generate high costs of maintenance, beyond generation risks to health and environment. Due to the fact that most of the equipment, tubing and pipes of production platforms are made of steel, in general, carbon steel, the industry of petroleum exploration will always coexist with the corrosive process. The use of a Corrosion Monitoring Plan to diagnostic, to control and to manage the evolution of corrosives process in off-shore oil platforms is the strategy proposed in this work to prevent problems as described above. The Internal Corrosion Monitoring Plan (ICMP, is based on lab analysis of the corrosively of fluids and residues showed periodically in off-shore operational platform; in the corrosion rate determined by the periodic use of test bodies installed inside off-shore oil platforms tubing systems, as mass loss coupons and electric resistance probes; and finally, in periodic operational data collect obtained during the off-shore oil platform systems operation. The ICMP will direct and manage the actions to be taken in case of aggravation of a corrosive process, quickly identifying to the corrosive mechanisms and its localization in the various systems of the platforms. The optimized use of the corrosion inhibitor and other chemical products are one of the main advantages of the ICMP.

  20. Corrosion Protection of Electrically Conductive Surfaces

    Directory of Open Access Journals (Sweden)

    Jian Song

    2012-11-01

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

  1. 49 CFR 192.477 - Internal corrosion control: Monitoring.

    Science.gov (United States)

    2010-10-01

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

  2. 49 CFR 192.491 - Corrosion control records.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Corrosion control records. 192.491 Section 192.491... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Requirements for Corrosion Control § 192.491 Corrosion... detail to demonstrate the adequacy of corrosion control measures or that a corrosive condition does...

  3. Corrosion Behaviour of Titanium Anodized Film in Different Corrosive Environments

    Directory of Open Access Journals (Sweden)

    Mr. Sunil D. Kahar

    2014-07-01

    Full Text Available Anodizing is an electrochemical process in which thickness of the natural oxide layer is increased and converted it into a decorative, durable, corrosion-resistant film. Titanium is used as a biocompatible material in human implants due to its excellent corrosion and wears resistance. Stable, continuous, highly adherent, and protective oxide films can be developed on titanium using various acid or alkaline baths. Anodizing of titanium generates a spectrum of different color without use of dyes. This spectrum of color dependent on the thickness of the oxide, voltage ranges, interference of light reflecting off the oxide surface and reflecting off the underlying metal surface. The anodized film of Titanium is mainly consists of TiO2 or mixtures of TiO2 & Ti2O3 etc. In the present work, Pure Titanium plate has been anodized using bath of Chromic Acid at different voltage range. The anodized film is characterized by visual observation, SEM & EDAX analysis & A.C Impedance Spectroscopy, while the corrosion studies were performed using Potentiodynamic studies were performed in 3.5% NaCl & 0.1N H2SO4. The Results show that the anodized film of Titanium show different spectrum of colors from Brown-Violet-Tea or Peacock. SEM & EDAX analyses show that the anodized film of Titanium is mainly made up of TiO2 and Ti2O3. Potentiodynamic study implies that the film developed on Titanium using the bath of Chromic Acid exhibits good corrosion resistance. The A.C. Impedance study shows that the film is more compact, adherent and more uniform in chromic acid bath.

  4. Bajo Peso al Nacer. Factores de riesgo y calidad de la atención Prenatal. Buenaventura. 2008-2009

    Directory of Open Access Journals (Sweden)

    Luis Enrique Gallardo-Ibarra

    2012-01-01

    Full Text Available Se realizó estudio descriptivo sobre Bajo Peso al Nacer, Área de Salud Buenaventura, bienio 2008-2009, sobre factores de riesgo y calidad de la atención médica recibida por las gestantes que aportaron recién nacidos bajo peso. Los datos estadísticos se obtuvieron mediante revisión de historias clínicas familiares, obstétricas y hospitalarias. Se emplearon métodos estadísticos histórico lógico, análisis y síntesis e inducción-deducción. Se obtuvo predominio del CIUR como variedad de Bajo Peso al Nacer, mostraron asociación con el bajo peso al nacer la valoración nutricional Bajo Peso materna al inicio de la gestación, insuficiente ganancia de peso, ingreso percápita bajo, malas condiciones de vivienda, antecedentes de dos o más abortos, multigestación, período intergenésico corto, HTA y sepsis cervicovaginal. La Atención Prenatal fue deficiente. No existió relación entre grupos de edades menores de 20 o mayor de 35 años y hábitos tóxicos con la aparición del bajo peso al nacer.

  5. A non-destructive test method to monitor corrosion products and corrosion-induced cracking in reinforced cement based materials

    DEFF Research Database (Denmark)

    Michel, Alexander; Pease, Bradley Justin; Peterova, Adela;

    2011-01-01

    ) was conducted to describe the impact of water-to-cement ratio and corrosion current density (i.e., corrosion rate) on the reinforcement corrosion process. Focus was placed, in particular on the determination of the corrosion accommodating region (CAR) and time to corrosion-induced cracking. Experimental results...

  6. INHIBITION OF STRESS CORROSION CRACKING OF CARBON STEEL STORAGE TANKS AT HANFORD

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-01-31

    The stress corrosion cracking (SCC) behavior of A537 tank steel was investigated in a series of environments designed to simulate the chemistry of legacy nuclear weapons production waste. Tests consisted of both slow strain rate tests using tensile specimens and constant load tests using compact tension specimens. Based on the tests conducted, nitrite was found to be a strong SCC inhibitor. Based on the test performed and the tank waste chemistry changes that are predicted to occur over time, the risk for SCC appears to be decreasing since the concentration of nitrate will decrease and nitrite will increase.

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

    Science.gov (United States)

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

    2016-01-01

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

  8. Electrochemical corrosion testing of metal waste forms

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-12-14

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

  9. CORROSION MONITORING OF PLUTONIUM OXIDE AND SNF

    Energy Technology Data Exchange (ETDEWEB)

    Douglas, D.G.; Haas, C.M.; Smith, C.M.; Ohl, P.C.

    2003-02-27

    While developing a method to measure pressure in totally sealed stainless steel containers holding spent nuclear fuel at the U.S. DOE Hanford Site, Vista Engineering Technologies, LLC (Vista Engineering) personnel adapted the central concept to corrosion monitoring techniques for the same containers. The ability to monitor corrosion within vessels containing spent nuclear fuel, plutonium and other hazardous materials is imperative for safe storage. Vista Engineering personnel have devised a way to monitor corrosion in a totally sealed stainless steel container using a Magnetically Coupled Corrosion Gauge (MCCG) Patent Pending. The MCCG can be used to detect corrosion as well as measure corrosion rate and does not require any penetration of the containment vessel, which minimizes pressure boundary surface area and sensitive weld materials in the vessels.

  10. Microbiologically Influenced Corrosion: an Update

    Science.gov (United States)

    2014-01-01

    the material that failed was carbon steel and the electrolyte were saline waters, but the microorgan- isms, the environments and the corrosion...different salinities . Martin et al.42 demonstrated that Ecorr ennoblement was site specific, varying 100 mV versus SCE between locations, with higher...microbial consortium of the fungus Aspergillus niger and bacteria influenced the corrosion–inhibiting effectiveness of Crz6 leached from chromate (CrO{24

  11. Parametric Instability Analysis of Deepwater Top-Tensioned Risers Considering Variable Tension Along the Length

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jie; TANG Yougang

    2015-01-01

    Parametric instability of a riser is caused by fluctuation of its tension in time due to the heave motion of floating plat-form. Many studies have tackled the problem of parametric instability of a riser with constant tension. However, tension in the riser actually varies linearly from the top to the bottom due to the effect of gravity. This paper presents the parametric instability analysis of deepwater top-tensioned risers (TTR) considering the linearly varying tension along the length. Firstly, the governing equation of transverse motion of TTR under parametric excitation is established. This equation is reduced to a system of ordinary differential equations by using the Galerkin method. Then the parametric instability of TTR for three calculation models are investigated by ap-plying the Floquet theory. The results show that the natural frequencies of TTR with variable tension are evidently reduced, the pa-rametric instability zones are significantly increased and the maximum allowable amplitude of platform heave is much smaller under the same damping; The nodes and antinodes of mode shape are no longer uniformly distributed along the axial direction and the am-plitude also changes with depth, which leads to coupling between the modes. The combination resonance phenomenon occurs as a result of mode coupling, which causes more serious damage.

  12. Static tensioning promotes hamstring tendons force relaxation more reliably than cycling tensioning.

    Science.gov (United States)

    Piedade, Sérgio Rocha; Dal Fabbro, Inácio Maria; Mischan, Martha Maria; Piedade, Cezar; Maffulli, Nicola

    2017-08-01

    Graft elongation might be a major reason for increased anterior laxity after anterior cruciate ligament (ACL) reconstruction. This study analyzed the force relaxation values and their stabilization when single strands of the gracilis and semitendinosus tendons underwent cyclic and static tensioning at 2.5% strain level, and compared the efficiency of static and cyclic tensioning in promoting force relaxation. Eighteen gracilis tendons and 18 semitendinosus tendons from nine male cadavers (mean age: 22.44years) were subjected to 10 in vitro cyclic loads at 2.5% strain level, or to a static load at 2.5% strain level. During cyclic loading, the reduction in force values tended to stabilize after the sixth cyclic load, while, in the case of static loading, this stabilization occurred by the second minute. Comparing static and cyclic loading, the gracilis tendon had similar mechanical responses in both conditions, while the semitendinosus tendon showed greater force relaxation in static compared with cyclic loading. Considering that the semitendinosus tendon is the main component of the hamstring graft, its biomechanical response to loading should guide the tensioning protocol. Therefore, static tensioning seems more effective for promoting force relaxation of the semitendinosus tendon than cyclic tensioning. The gracilis tendon showed a similar mechanical response to either tensioning protocols. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Aluminum corrosion product release kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, Matt, E-mail: Matthew.Edwards@cnl.ca; Semmler, Jaleh; Guzonas, Dave; Chen, Hui Qun; Toor, Arshad; Hoendermis, Seanna

    2015-07-15

    Highlights: • Release of Al corrosion product was measured in simulated post-LOCA sump solutions. • Increased boron was found to enhance Al release kinetics at similar pH. • Models of Al release as functions of time, temperature, and pH were developed. - Abstract: The kinetics of aluminum corrosion product release was examined in solutions representative of post-LOCA sump water for both pressurized water and pressurized heavy-water reactors. Coupons of AA 6061 T6 were exposed to solutions in the pH 7–11 range at 40, 60, 90 and 130 °C. Solution samples were analyzed by inductively coupled plasma atomic emission spectroscopy, and coupon samples were analyzed by secondary ion mass spectrometry. The results show a distinct “boron effect” on the release kinetics, expected to be caused by an increase in the solubility of the aluminum corrosion products. New models were developed to describe both sets of data as functions of temperature, time, and pH (where applicable)

  14. Corrosion behavior in heat pipe

    Directory of Open Access Journals (Sweden)

    Anurak Rodbumrung

    2016-01-01

    Full Text Available The aim of this study was to perform life testing and determine the effect of working fluid on the corrosion of a heat pipe with a sintered wick. The heat pipe was made from a copper tube. The inner heat pipe was filled with 99.97% pure copper powder as a dendritic for the sintering process. The heat pipe had an outer diameter of 6 mm with a length of 200 mm, and distilled water and ethanol were the working fluids. The operating temperature at the evaporator was 125°C. The analysis consisted of using a scanning electron microscope, energy dispersive X-ray spectrometry and atomic absorption spectroscopy. The results of the scanning electron microscope and energy dispersive X-ray spectrometry analysis showed that the corrosion of the heat pipe was uniform. The result of the atomic absorption spectroscopy indicated that the concentration of the copper in the ethanol as the working fluid was greater than in the distilled water as the working fluid, and the highest concentration of copper particles in the ethanol was 22.7499 ppm or 0.0409 mg after testing for 3000 h. The concentration of copper was higher when the length of the life test increased due to corrosion of the heat pipe.

  15. Corrosion Preventive Compounds Lifetime Testing

    Science.gov (United States)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  16. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

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

  17. Corrosion performance of iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Natesan, K.

    1993-03-01

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

  18. DESARROLLO E IMPLEMENTACIÓN DE FOTOCONTROL TEMPORIZADO CON TECNOLOGÍA DE BAJO CONSUMO

    Directory of Open Access Journals (Sweden)

    Fredy Hernán Martínez Sarmiento

    2013-09-01

    Full Text Available En este trabajo se presenta el desarrollo e implementación de un fotocontrol con tecnología de bajo consumo desarrollado con un microcontrolador, el cual controla variables de tensión, luminosidad  y sincronización con la red, por medio de  una salida con modo PWM producir una salida de Vdc en el relé. El microcontrolador realiza un  muestreo análogo de voltaje sobre la onda sinusoidal y se hace un filtro de promedio móvil para eliminar ruido de la onda.La temporización se realiza cuando el contacto del relé está cerrado y el tiempo a temporizar es programado por el usuario el cual lo requiera, el fotocontrol presenta un modo de ultra bajo consumo en el microcontrolador con un supercap.

  19. Estudio de una Cronosecuencia de Suelos en el Bajo Cauca (Antioquia

    Directory of Open Access Journals (Sweden)

    Jaramillo J. Daniel F.

    1996-09-01

    Full Text Available En la región del Bajo Cauca, Antioquia, se estudiaron tres terrazas, a diferentes alturas, las cuales poseen diferencias apreciables entre la evolución de sus respectivos suelos. La terraza de mayor altura presentó los suelos más evolucionados: Typic Paleudult; la de mediana altura presentó suelos de incipiente evolución, clasificados como Typic Dystropept y la de menor altitud presentó suelos recientes, con muy bajo grado de evolución: Tropic Fluvaquent. Las diferencias en evolución observadas entre los suelos se deben a los largos intervalos de tiempo transcurridos entre la formación de los tres niveles de las terrazas. La fertilidad natural de los suelos desarrollados sobre las terrazas alta y media se puede calificar como baja a muy baja; por su parte, la terraza a menor altura posee alta fertilidad.

  20. Optimising corrosion monitoring in district heating systems

    DEFF Research Database (Denmark)

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

    2002-01-01

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

  1. Recognition and Analysis of Corrosion Failure Mechanisms

    OpenAIRE

    Steven Suess

    2006-01-01

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

  2. Corrosive acid injury of the stomach.

    Science.gov (United States)

    Wijeratne, T; Ratnatunga, C; Dharrmapala, A; Samarasinghe, T

    2015-03-01

    Ingestion of corrosives with accidental or suicidal intent is a common problem in Sri Lanka. Management options and outcomes of corrosive injuries on stomach are not well documented in our setting. The clinical presentation, complications and management outcomes of nine patients with corrosive injury to stomach are presented. Gastric outlet obstruction seen in majority, was managed with bypass procedure (n=5) or resection (n=4). The outcomes of management were successful with both methods.

  3. The oxidation and corrosion of ODS alloys

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1990-01-01

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

  4. Oxidation And Hot Corrosion Of ODS Alloy

    Science.gov (United States)

    Lowell, Carl E.; Barrett, Charles A.

    1993-01-01

    Report reviews oxidation and hot corrosion of oxide-dispersion-strengthened (ODS) alloys, intended for use at high temperatures. Classifies environmental resistances of such alloys by rates of growth of oxides, volatilities of oxides, spalling of oxides, and limitations imposed by hot corrosion. Also discusses environmentally resistant coatings for ODS materials. Concludes ODS NICrAl and FeCrAl alloys highly resistant to oxidation and corrosion and can be used uncoated.

  5. Corrosion of oil-fired domestic boilers

    Energy Technology Data Exchange (ETDEWEB)

    Koebel, M.; Elsener, M.

    1989-05-01

    Depending on the surface temperature of the flue gas side the corrosion of oil fired domestic boilers proceeds either mainly by acid corrosion or by oxygen corrosion: (1) At surface temperatures of 60/sup 0/C and higher the corrosion mechanism of acid corrosion prevails and the corrosion rates amount to 0.1-0.3 mm/year (values referred to continuous burner operation). The corrosion products consist of soluble iron(II)- and iron(III)sulfates. Higher corrosion rates can be attributed to an appreciable catalytic formation of sulfur trioxide on the corrosion products formed on the convective heating surfaces. (2) At surface temperatures of 40/sup 0/C the mechanism of oxygen corrosion already dominates and the corrosion rates are about ten times higher (1.5-3 mm/year, referred to continuous burner operation). The high portion of iron oxide hydrates, especially goethit (/alpha/-FeOOH), makes the corrosion products difficult to remove. (3) Distinctly reduced service lives are also expected for the so called reduced temperature boilers ('Niedertemperaturkessel') and low temperature boilers ('Tieftemperaturkessel'): According to the manufacturers these boilers may be operated at boiler water temperatures well below 60/sup 0/C, as they are equipped with constructive measures to enhance the surface temperature on the flue gas side. However, these measures are only fully effective under stationary conditions. Some of the results were obtained from weight loss measurements on test specimen made from St 35.8 and gray cast iron, that were exposed to the flue gases of an fired experimental boiler. Other important results come from field measurements of the sulfuric acid content of about 30 boilers that are in practical use. (orig.).

  6. Natural analogues of nuclear waste glass corrosion.

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-01-06

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

  7. Recognition and Analysis of Corrosion Failure Mechanisms

    OpenAIRE

    Steven Suess

    2006-01-01

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

  8. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

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

  9. Simulation Analysis of Standard Metal Specimen Tension Experiment by Fem

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Some standard metal rod-shaped, plate-shaped or pipe-shaped specimens usually are used to be tensioned to acquire the material properties such as tensional ductility, contractibility ratio on breaking section,

  10. Preferencia Relativa Bajo Pastoreo de Varios Ecotipos de la Leguminosa Sfylosanthes spp.

    Directory of Open Access Journals (Sweden)

    Giraldo Valderrama Luis Alfonso

    1988-09-01

    Full Text Available Con el objeto de determinar la variabilidad en preferencia y detectar ecotipos de Stylosanthes spp. con problemas de aceptabilidad, se evaluaron 10 ecolipos de Stylosanthes guianensis mediante un ensayo bajo pastoreo tipo cafetería. Dado que la preferencia varía según características morfológicas de las plantas, se determinó el hábito de crecimiento y el grado de viscosidad al tacto de cada ecotipo de leguminosa. La aceptabilidad se midió mediante la frecuencia de veces que fue pastoreado cada ecotipo (medida por un índice de preferencia por ocho animales bovinos machos de la raza cebú, que permanecieron en las parcelas siete días, cuyas observaciones se realizaron durante siete horas por día. En general, los Stylosanthes guianensis podrían tener problemas de preferencia bajo pastoreo, dado el bajo índice de preferencias encontrado. La mayor preferencia correspondió a Stylosanthes guianensis ecotipos 1280 y 1633, entre los ecotipos restantes no existió diferencia marcada en gustosidad. El patrón de preferencia, parece estar ligado al hábito de crecimiento de la planta y a la dinámica de la disponibilidad inicial de forraje. Las pruebas de preferencia relativa de leguminosas bajo pastoreo permiten detectar ecotipos con problemas y conformar un "ranking" de leguminosas, componentes importantes en el diseño de estrategias de manejo en asociaciones gramíneas-leguminosas para la alimentación animal.

  11. Biología de Delphastus quinculus (Gordon 1994) (Coleoptera : Coccinellidae) bajo diferentes temperaturas

    OpenAIRE

    2015-01-01

    Universidad Nacional Agraria La Molina. Escuela de Posgrado. Maestría en Entomología Delphastus quinculus (Gordon, 1994) es un predador que ha sido reportado importante, para el control del complejo de la mosca blanca de los invernaderos Trialeurodes vaporariorum (Westwood, 1856). Para obtener información sobre algunos aspectos de su biología y el efecto de la temperatura en su desarrollo, se realizaron experimentos bajo condiciones de laboratorio a seis1temperaturas constantes...

  12. Sistemas urbanos alternativos para el biotratamiento y reciclaje de aguas residuales en colonias de bajos ingresos

    OpenAIRE

    Jan Bazant

    2003-01-01

    En México, los gobiernos locales no cuentan con suficientes recursos financieros ni reservas hídricas para extender las redes de infraestructura hacia asentamientos de población de bajos ingresos que atomizada y desordenadamente van ocupando las periferias de las ciudades. Se plantea en este artículo un sistema urbano alternativo que proporcione soluciones técnicamente viables al problema del abastecimiento de agua en las periferias. La canalización y tratamiento...

  13. Bajo rendimiento escolar: una perspectiva desde el desarrollo del sistema nervioso

    Directory of Open Access Journals (Sweden)

    K. Shapiro Bruce, MD.

    2011-03-01

    Full Text Available El bajo rendimiento escolar es un problema frecuente y tiene múltiples causas; las alteraciones que lo caracterizan, se expresan fundamentalmente en las áreas de funcionamiento cognitivo, académico y conductual. El bajo rendimiento escolar es una vía final común de diferentes trastornos, etiologías y mecanismos. Es habitual la presencia de múltiples alteraciones, porque la disfunción cerebral en la niñez generalmente afecta a muchas funciones. Consecuente con lo anterior, los programas de manejo deben ser individualizados, comprensivos e incorporar aspectos del niño en particular, la escuela y la familia. La planificación del tratamiento incluye, educación y entrenamiento de los padres, adecuaciones académicas, técnicas para mantener la autoestima y un enfoque psicofarmacológico. Es necesario monitorear en forma continua los programas de manejo especialmente para detectar comorbilidades importantes que puedan emerger, para realizar modificaciones que se adecuen a los cambios en las demandas académicas y sociales a las diferentes edades del niño y para proveer de información actualizada. Las consecuencias que tenga el bajo rendimiento escolar para el niño dependerán en medida importante de las alteraciones subyacentes. El personal de salud tiene múltiples roles en la prevención, detección, diagnóstico y manejo del niño con bajo rendimiento escolar.

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

    CERN Document Server

    Groysman, Alec

    2017-01-01

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

  15. Accelerated corrosion testing results for specimens containing uncoated reinforcing steel and corrosion inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Kondratova, I. L.; Montes, P.; Bremner, T. W. [New Brunswick Univ., Dept, of Civil Engineering, Fredericton, NB (Canada)

    2000-07-01

    Concrete mixtures (water-cement ratios of 0.25, 0.40. or 0.60) containing uncoated reinforcing bars with a simulated crack, formed transverse to the axis of the bar, and with three commercial corrosion inhibitors added for corrosion protection (organic corrosion inhibitor,calcium nitrate-based corrosion inhibitor, and migratory corrosion inhibitor), were tested for corrosion damage. The objective was to evaluate the effectiveness of the different corrosion inhibitors in uncracked and cracked concrete slabs in a simulated marine environment. The specimens were placed in an accelerated exposure cabinet with four cycles of wetting and drying per day in simulated seawater, and corrosion rates measured using the linear polarization technique. Water-soluble chloride content in the rebars was analyzed at the end of the exposure period. The three corrosion inhibitors were found to show a wide variation in performance. There was a direct correlation between their effectiveness and addition rate. All three appeared to be more effective in reducing corrosion rate in a higher water-to-cement ratio concrete. Consistent performance was provided only by calcium nitrate at an addition rate of 25 litre/cu m of concrete, with water-to-cement ratios of 0.60 and 0.40. Pitting corrosion was observed in all pre-cracked high performance concrete specimens; the depth of the pit tended to be deeper when a corrosion inhibitor was used. 6 refs., 6 tabs., 6 figs.

  16. New corrosion issues in gas sweetening plants

    Energy Technology Data Exchange (ETDEWEB)

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

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

  17. Fouling corrosion in aluminum heat exchangers

    Directory of Open Access Journals (Sweden)

    Su Jingxin

    2015-06-01

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

  18. Classification of corrosion risk zones using GIS

    Science.gov (United States)

    Georgiou, Nikolas; Anastasiou, Constantina; Tantele, Elia A.; Votsis, Renos A.; Danezis, Chris

    2016-08-01

    Corrosion of steel reinforcement is the major deterioration factor of the RC infrastructures. Several factors are contributing towards increasing the corrosion risk like the exposure and environmental conditions which are a function of the geographical location of the infrastructure. Information for these conditions and their affected areas can be proved valuable at design stage and/or during maintenance planning. This study aims to relate corrosion risk of RC infrastructures with their geographical location. The corrosion risk is quantified through data from NDT methods and subsequently correlated with its location. Therefore high risk areas with structures prone to corrosion deterioration are identified. The latter is implemented via GIS tools in order to create maps that describe how corrosion risk is related to the location of each structure. Two GIS methods are suggested, the grid system and the use of classified areas. Corrosion data has been collected from labs about various constructions in Cyprus and used in conjunction with GIS tools to provide useful information on corrosion identification. The outcome is a digitized map of the Limassol area which indicates the risks levels associated with corrosion of the steel reinforcement.

  19. NOVEL CORROSION SENSOR FOR VISION 21 SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2004-12-01

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

  20. Recent Corrosion Research Trends in Weld Joints

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2007-04-15

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  1. Corrosion Fatigue in District Heating Water Tanks

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel

    1996-01-01

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

  2. Perfil cognitivo de niños con rendimientos bajos en comprensión lectora

    Directory of Open Access Journals (Sweden)

    Lorena Canet-Juric

    2013-10-01

    Full Text Available La mayoría de los niños con dificultades en la comprensión lectora poseen rendimientos inferiores en un conjunto de procesos cognitivos. El objetivo del presente estudio es establecer un perfil cognitivo asociado al bajo rendimiento en comprensión lectora en relación a la habilidad de monitoreo, a la producción de inferencias, al vocabulario, a la amplitud de memoria de trabajo y a la capacidad inhibitoria, en niños hispanoparlantes. Para ello se administraron tareas correspondientes a dichos procesos en niños con altos y bajos rendimientos en comprensión lectora. Los resultados mostraron que si bien los niños con mala comprensión presentan bajos rendimientos en estas habilidades, no puede establecerse un perfil consistente ya que hay niños con problemas en comprensión que presentan normal o superior rendimiento en algunas de estas habilidades cognitivas.

  3. Actualización en el manejo del colesterol hdl bajo

    Directory of Open Access Journals (Sweden)

    Rigotti R. Attilio, Dr.

    2012-11-01

    Full Text Available Los niveles plasmáticos bajos de colesterol transportado en las lipoproteínas de alta densidad (HDL constituyen un elemento independiente de riesgo cardiovascular ateroesclerótico. Algunos protocolos clínicos enfocados en el manejo farmacológico de los niveles bajos de colesterol HDL en pacientes de alto riesgo cardiovascular han mostrado resultados favorables. Por otro lado, existen nuevas formulaciones de la niacina, el agente farmacológico disponible más efectivo para el manejo del colesterol HDL bajo, y se están desarrollando nuevos fármacos más potentes para aumentar los niveles plasmáticos de colesterol HDL. En el futuro, nuevos medicamentos que modulen el metabolismo de HDL y demuestren beneficio sobre el control del riesgo cardiovascular ateroesclerótico, podrían mejorar aún más el manejo actual de esta condición patológica que se basa esencialmente en el uso de estatinas.

  4. La diversidad, una herramienta poderosa para el desarrollo de una agricultura de bajos-insumos

    Directory of Open Access Journals (Sweden)

    M.J. Suso

    2013-01-01

    Full Text Available El desarrollo de estrategias de mejora que vinculen la diversidad biológica y los servicios productivos y de regulación de los cultivos es un imperativo cuando se trata de la promoción de una agricultura de bajos-insumos (en la que se incluye la agricultura ecológica. En los sistemas de bajosinsumos, la producción tiene que basarse en los utensilios suministrados por la diversidad dentro y entre cultivos, usar los recursos locales e incluir a las variedades tradicionales, como fuente de genes útiles y de genotipos, para el desarrollo de nuevas variedades o para que las variedades locales evolucionen como nuevas poblaciones. Los sistemas de bajos-insumos requieren una mejora descentralizada y participativa diseñada para incorporar el "know-how" de los agricultores y la perspectiva de los consumidores. Caracteres del cultivo que permitan la reducción de los insumos, como la eficiencia en el uso de la asociación con especies beneficiosas tales como los polinizadores aumentarán en importancia. Este artículo describe aproximaciones de mejora dirigidas a la implementación de una sinergia entre los servicios de producción y de regulación prestados por la agricultura en el contexto de sistemas de bajos-insumos.

  5. Surface and interfacial tension measurement, theory, and applications

    CERN Document Server

    Hartland, Stanley

    2004-01-01

    This edited volume offers complete coverage of the latest theoretical, experimental, and computer-based data as summarized by leading international researchers. It promotes full understanding of the physical phenomena and mechanisms at work in surface and interfacial tensions and gradients, their direct impact on interface shape and movement, and their significance to numerous applications. Assessing methods for the accurate measurement of surface tension, interfacial tension, and contact angles, Surface and Interfacial Tension presents modern simulations of complex interfacial motions, such a

  6. Modelling Tension Stiffening in Reinforced Concrete Structures

    DEFF Research Database (Denmark)

    Christiansen, Morten Bo; Nielsen, Mogens Peter

    1997-01-01

    flexure.In the first model, the yield zone model, it is assumed that the mean crack distance is a descending function of the reinforcement stress in a crack. Furthermore it is assumed that in certain zones between the cracks the concrete is carrying its full effective tensile strength, i.e. the concrete...... with deformations in reinforced concrete disks subjected to pure shear.A physical model for the shear stress-shear strain behaviour of disks, including tension stiffening, is proposed.In the disk model it is assumed that the tensile principal stress in the concrete decreases linearly from the initiation of cracking...... until a certain load level. At any load level the model can predict the shear strains of the disk and the inclination of the crack system. When regarding tension stiffening this latter parameter will be a function of the load level.The model is compared with experimental data, and in the light...

  7. Scaling for interfacial tensions near critical endpoints.

    Science.gov (United States)

    Zinn, Shun-Yong; Fisher, Michael E

    2005-01-01

    Parametric scaling representations are obtained and studied for the asymptotic behavior of interfacial tensions in the full neighborhood of a fluid (or Ising-type) critical endpoint, i.e., as a function both of temperature and of density/order parameter or chemical potential/ordering field. Accurate nonclassical critical exponents and reliable estimates for the universal amplitude ratios are included naturally on the basis of the "extended de Gennes-Fisher" local-functional theory. Serious defects in previous scaling treatments are rectified and complete wetting behavior is represented; however, quantitatively small, but unphysical residual nonanalyticities on the wetting side of the critical isotherm are smoothed out "manually." Comparisons with the limited available observations are presented elsewhere but the theory invites new, searching experiments and simulations, e.g., for the vapor-liquid interfacial tension on the two sides of the critical endpoint isotherm for which an amplitude ratio -3.25+/-0.05 is predicted.

  8. Thermal Analysis of Bending Under Tension Test

    DEFF Research Database (Denmark)

    Ceron, Ermanno; Martins, Paulo A.F.; Bay, Niels

    2014-01-01

    The tribological conditions in deep drawing can be simulated in the Bending Under Tension test to evaluate the performance of new lubricants, tool materials, etc. Deep drawing production with automatic handling runs normally at high rate. This implies considerable heating of the tools, which...... sometimes can cause lubricant film breakdown and galling. In order to replicate the production conditions in bending under tension testing it is thus important to control the tool/workpiece interface temperature. This can be done by pre-heating the tool, but it is essential that the interface temperature...... during testing is similar to the one in the production tool. A universal sheet tribo-tester has been developed, which can run multiple tests automatically from coil. This allows emulating the temperature increase as in production. The present work performs finite element analysis of the evolution...

  9. Separation anxiety: Stress, tension and cytokinesis

    Energy Technology Data Exchange (ETDEWEB)

    Mohan, Krithika [Department of Electrical and Computer Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Iglesias, Pablo A., E-mail: pi@jhu.edu [Department of Electrical and Computer Engineering, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218 (United States); Robinson, Douglas N., E-mail: dnr@jhmi.edu [Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 (United States)

    2012-07-15

    Cytokinesis, the physical separation of a mother cell into two daughter cells, progresses through a series of well-defined changes in morphology. These changes involve distinct biochemical and mechanical processes. Here, we review the mechanical features of cells during cytokinesis, discussing both the material properties as well as sources of stresses, both active and passive, which lead to the observed changes in morphology. We also describe a mechanosensory feedback control system that regulates protein localization and shape progression during cytokinesis. -- Highlights: Black-Right-Pointing-Pointer Cytokinesis progresses through three distinct mechanical phases. Black-Right-Pointing-Pointer Cortical tension initially resists deformation of mother cell. Black-Right-Pointing-Pointer Late in cytokinesis, cortical tension provides stress, enabling furrow ingression. Black-Right-Pointing-Pointer A mechanosensory feedback control system regulates cytokinesis.

  10. Bending Under Tension Test with Direct Friction Measurement

    DEFF Research Database (Denmark)

    Andreasen, Jan Lasson; Olsson, David Dam; Chodnikiewicz, K.

    2004-01-01

    A special BUT-transducer has been developed in which friction around the tool radius can be directly measured when drawing a plane sheet strip around a cylindrical tool-pin under constant back tension. The front tension, back tension and torque on the tool-pin are all measured directly, thus enab...

  11. Tensions of Teaching Media Literacy in Teacher Education

    Science.gov (United States)

    Ngomba-Westbrook, Nalova Elaine

    2013-01-01

    This study investigates the tensions a teacher educator faces in facilitating a media literacy teacher education course at the university level. Teaching tensions are conceptualized as a three-tier framework. At the first level, tensions may arise in the selection and application of pedagogies associated with critical and new/21st century…

  12. The effect of organic matter associated with the corrosion products on the corrosion of mild steel in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Wagh, A.B.

    the corrosion of mild steel and the temperature and dissolved oxygen of seawater. In contrast to this, the corrosion and mild steel was inversely related to the organic carbon and water extractable carbohydrates associated with the corrosion products of mild...

  13. A microprocessor based portable bolt tension monitor

    Science.gov (United States)

    Perey, D. F.

    1991-01-01

    A bolt tension monitor (BTM) which uses ultrasonics and a pulsed phase locked loop circuit to measure load-induced acoustic phase shifts which are independent of friction is described. The BTM makes it possible to measure the load in a bolt that was tightened at some time in the past. This capability to recertify a load after-the-fact will help to insure the integrity of a bolted joint.

  14. 2-rational Cubic Spline Involving Tension Parameters

    Indian Academy of Sciences (India)

    M Shrivastava; J Joseph

    2000-08-01

    In the present paper, 1-piecewise rational cubic spline function involving tension parameters is considered which produces a monotonic interpolant to a given monotonic data set. It is observed that under certain conditions the interpolant preserves the convexity property of the data set. The existence and uniqueness of a 2-rational cubic spline interpolant are established. The error analysis of the spline interpolant is also given.

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

    Science.gov (United States)

    Calle, Luz Marina

    2014-01-01

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

  16. Environmental Friendly Coatings and Corrosion Prevention For Flight Hardware Project

    Science.gov (United States)

    Calle, Luz

    2014-01-01

    Identify, test and develop qualification criteria for environmentally friendly corrosion protective coatings and corrosion preventative compounds (CPC's) for flight hardware an ground support equipment.

  17. Tension-induced binding of semiflexible biopolymers

    CERN Document Server

    Benetatos, Panayotis; Zippelius, Annette

    2014-01-01

    We investigate theoretically the effect of polymer tension on the collective behavior of reversibly binding cross-links. For this purpose, we employ a model of two weakly bending wormlike chains aligned in parallel by a tensile force, with a sequence of inter-chain binding sites regularly spaced along the contours. Reversible cross-links attach and detach at the sites with an affinity controlled by a chemical potential. In a mean-field approach, we calculate the free energy of the system and find the emergence of a free-energy barrier which controls the reversible (un)binding. The tension affects the conformational entropy of the chains which competes with the binding energy of the cross-links. This competition gives rise to a sudden increase in the fraction of bound sites as the tension increases. We show that this transition is related to the cross-over between weak and strong localization of a directed polymer in a pinning potential. The cross-over to the strongly bound state can be interpreted as a mechan...

  18. Evaluation of the problematic of corrosion in bottoms of tanks of crude oil storage; Evaluacion de la problematica de corrosion en fondos de tanques de almacenamiento de petroleo crudo

    Energy Technology Data Exchange (ETDEWEB)

    Malo T, Jose M; Uruchurtu C, Jorge; Meza, Beatriz [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Lopez C, Luis F [Region Marina Suroeste, Pemex (Mexico)

    2003-07-01

    resultados relacionados con la agresividad corrosiva de los fluidos de agua de crudo de la Terminal Maritima de Dos Bocas (TMDB), sobre la efectividad de los metodos de control anticorrosivo y sobre medidas de control que podrian adoptarse. Asimismo, este articulo forma parte de un trabajo realizado por personal del Instituto de Investigaciones Electricas (IIE) durante el ano 2002. La corrosion en tanques es de naturaleza electroquimica y tiene su origen en la fase acuosa que acompana al crudo al ser extraido del subsuelo. En el caso de los tanques de almacenamiento, la fase acuosa se separa en el fondo, ocasionado el mojado de las placas de acero del fondo y su degradacion. Debido al limitado acceso al interior del tanque durante su operacion, se diseno un dispositivo de pruebas que fue conectado a una valvula de drenado de un tanque de la terminal. El trabajo experimental busco evaluar la agresividad de los fluidos, el tipo de productos de corrosion formados y la eficacia de la proteccion catodica y de los recubrimientos. Adicionalmente, se recolectaron muestras de fluidos para analizar el nivel de agresividad natural que presenta el agua de los tres tipos de crudos: Maya, Olmeca e Istmo, manejados en la terminal, estudiando muestras de acero y de fluidos de planta bajo condiciones controladas de laboratorio. La agresividad se obtuvo de mediciones de velocidades de reaccion de corrosion y de analisis de actividad microbiana. Se analizo la factibilidad de aplicar el metodo de proteccion catodica, observando su efectividad, asi como formas particulares de corrosion como la que ocurre en los pontones. Los resultados del estudio conducen a proponer un esquema de monitoreo para el seguimiento de la integridad de los recubrimientos, la operacion de la proteccion catodica y la corrosion en tanques, con el que se podria tener un mejor control de la operacion de los metodos anticorrosivos y de la degradacion que ocurre por corrosion.

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

    Science.gov (United States)

    1975-01-01

    source, consisting of " artificial " anodes energized by rectified A.C. or galvanic voltage, is used. Where current leaves a metal surface, corrosion occurs...additional data. 2 Losses of weight sustained by 5.1- by 10.2- cm. (2- by 4- inc.) specimens made of open- hearth iron (0.007 percent copper) are used as a...Al(OH)3 ) that forms, tending to prevent further cor- rosion. This film can be artificially induced by anodizing, passing electric current through

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

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

    DEFF Research Database (Denmark)

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

    2017-01-01

    A majority of printed circuit board surfaces are covered with tin, therefore tin corrosion under humid conditions and movement of tin ions under the influence of an electric field plays an important role in the corrosion failure development. Tracking tin corrosion products spread on the printed...... a colorimetric tin ion indicator applied as a gel. The examples provided in this paper include visualization of corrosion caused by weak organic acids found in solder fluxes, corrosion profiling on the PCBAs after climatic device level testing, and failure analysis of field returns....

  2. Screening of soil corrosivity by field testing: Results and design of an electrochemical soil corrosion probe

    DEFF Research Database (Denmark)

    Nielsen, Lars vendelbo; Bruun, Niels Kåre

    1996-01-01

    The corrosivity of different types of soil have been assessed by exposing carbon-steel plates at 50 different locations in Denmark for an extended period of time. The investigations included weight loss measurements and analysis of the chemical compositions of the corrosion products formed...... on the plates during exposure. An electrochemical soil corrosion probe has been designed and manufactured allowing for simultaneous measurements of several qauntities to predict corrosion. The probe consists of individual sections capable of measuring redox-potential, corrosion potential, soil resistivity...

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  4. Novel Corrosion Sensor for Vision 21 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban; Bharat Soni

    2007-03-31

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall goal of this project is to develop a technology for on-line fireside corrosion monitoring. This objective is achieved by the laboratory development of sensors and instrumentation, testing them in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. This project successfully developed two types of sensors and measurement systems, and successful tested them in a muffle furnace in the laboratory. The capacitance sensor had a high fabrication cost and might be more appropriate in other applications. The low-cost resistance sensor was tested in a power plant burning eastern bituminous coals. The results show that the fireside corrosion measurement system can be used to determine the corrosion rate at waterwall and superheater locations. Electron microscope analysis of the corroded sensor surface provided detailed picture of the corrosion process.

  5. Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

    Science.gov (United States)

    Hannigan, K.; Reid, M.; Collins, M. N.; Dalton, E.; Xu, C.; Wright, B.; Demirkan, K.; Opila, R. L.; Reents, W. D.; Franey, J. P.; Fleming, D. A.; Punch, J.

    2012-03-01

    Recently, the corrosion resistance of printed wiring board (PWB) finishes has generated considerable interest due to field failures observed in various parts of the world. This study investigates the corrosion issues associated with the different lead-free PWB surface finishes. Corrosion products on various PWB surface finishes generated in mixed flowing gas (MFG) environments were studied, and analysis techniques such as scanning electron microscopy, energy-dispersive x-ray, x-ray diffraction, focused ion beam, and scanning Auger microscopy were used to quantify the corrosion layer thickness and determine the composition of corrosion products. The corrosion on organic solderability preservative samples shows similar corrosion products to bare copper and is mainly due to direct attack of copper traces by corrosive gases. The corrosion on electroless nickel immersion gold occurs primarily through the porosity in the film and is accelerated by the galvanic potential between gold and copper; similar results were observed on immersion silver. Immersion tin shows excellent corrosion resistance due to its inherent corrosion resistance in the MFG environment as well as the opposite galvanic potential between tin and copper compared with gold or silver and copper.

  6. Effect of Flow Velocity on Corrosion Rate and Corrosion Protection Current of Marine Material

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seong Jong [Kunsan National University, Kunsan (Korea, Republic of); Han, Min Su; Jang, Seok Ki; Kim, Seong Jong [Mokpo National Maritime University, Mokpo (Korea, Republic of)

    2015-10-15

    In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process. Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

  7. Corrosion Products and Formation Mechanism During Initial Stage of Atmospheric Corrosion of Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    XIAO Kui; DONG Chao-fang; LI Xiao-gang; WANG Fu-ming

    2008-01-01

    The formation and development of corrosion products on carbon steel surface during the initial stage of atmospheric corrosion in a laboratory simulated environment have been studied by scanning electron microscopy (SEM)and Raman spectroscopy.The results showed that two different shapes of corrosion products,that is,ring and chain,were formed in the initial stage of corrosion.MnS clusters were found in the nuclei of corrosion products at the active local corrosion sites.The ring-shaped products were composed of lepidocrocite (γ-FeOOH) and maghemite(γ-Fe2 O3) transformed from lepidocrocite.The chain-type products were goethite (α-FeOOH).A formation mechanism of the corrosion products is proposed.

  8. Corrosion Mechanism of Corrosion-Resistant Steel Developed for Bottom Plate of Cargo Oil Tanks

    Institute of Scientific and Technical Information of China (English)

    Feilong SUN; Xiaogang LI; Fan ZHANG; Xuequn CHENG; Cheng ZHOU; Nianchun WU; Yuqun YIN

    2013-01-01

    A new type of corrosion-resistant steel consisting of ferrite and bainite phases was developed for cargo oil tanks of crude oil tankers.The corrosion rate of this new steel was 0.22 mm/a,which was equivalent to ca.1/5 of the criterion (≤ 1 mm/a) for corrosion-resistant steels.The composition and element distribution of the corrosion products were investigated by micro-Raman spectrometry and energy dispersive spectrometer.The results demonstrated that the corrosion product was composed of α-FeOOH,Fe3O4 and a continuous Cu enrichment layer.This kind of corrosion product was protective to the steel matrix and accounted for the enhancement of the corrosion resistance of the new developed steel.

  9. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Institute of Scientific and Technical Information of China (English)

    Shengrong Wang; Cuiwei Dun; Xiaogang Li; Zhiyong Liunn; Min Zhu; Dawei Zhang

    2015-01-01

    The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM),energy dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface.α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS) are consistent with potentiodynamic polarization tests.

  10. Field corrosion characterization of soil corrosion of X70 pipeline steel in a red clay soil

    Directory of Open Access Journals (Sweden)

    Shengrong Wang

    2015-06-01

    Full Text Available The corrosion behavior of X70 pipeline steel buried in red soil environment has been studied. The surface morphology and elemental distribution were determined by scanning electron microscopy (SEM,energy dispersive X-ray spectroscopy (EDS, and X-ray diffraction (XRD. The corrosion kinetics was evaluated by weight loss measurement. The results show that in red soil, the corrosion rate of X70 steel decreases with time, and follows the exponential decay law. General corrosion with non-uniform and localized pitting occurred on the steel surface. α-FeOOH was the dominate products during corrosion in whole buried periods, and the corrosion products exhibited well protective properties. The potentiodynamic polarization tests revealed that icorr decreased with time, indicating the improvement of corrosion resistance. The results of Electrochemical impendence spectroscopy (EIS are consistent with potentiodynamic polarization tests.

  11. Effects of alternating magnetic field on the corrosion rate and corrosion products of copper

    Institute of Scientific and Technical Information of China (English)

    GUO Bin; ZHANG Peng; JIN Yongping; CHENG Shukang

    2008-01-01

    The effects of alternating magnetic field on the corrosion morphologies, corrosion rate, and corrosion products of copper in 3.5% NaCl solution, sea water, and magnetized sea water were investigated using electrochemical test, scanning electron microscopy/energy dispersive analysis system of X-ray (SEM/EDAX), and X-ray diffraction (XRD). The results show that the corrosion rate of copper in magnetized sea water is minimal. Moreover, the surface of the specimen in magnetized sea water is uniform and compact as compared with those in 3.5% NaCl solution and sea water. The corrosion products of copper in magnetized sea water are mainly Cu2O and CuCl2. However, the corrosion products in sea water are CuCl, Cu2Cl(OH)3, and FeCl3·6H2O. The electrochemical corrosion mechanisms of copper in the three media were also discussed.

  12. Corrosivity of paper mill effluent and corrosion performance of stainless steel.

    Science.gov (United States)

    Ram, Chhotu; Sharma, Chhaya; Singh, A K

    2015-01-01

    Present study relates to the corrosivity of paper mill effluent and corrosion performance of stainless steel (SS) as a construction material for the effluent treatment plant (ETP). Accordingly, immersion test and electrochemical polarization tests were performed on SS 304 L, 316 L and duplex 2205 in paper mill effluent and synthetic effluent. This paper presents electrochemical polarization measurements, performed for the first time to the best of the authors' information, to see the influence of chlorophenols on the corrosivity of effluents. The corrosivity of the effluent was observed to increase with the decrease in pH and increase in Cl- content while the addition of SO4- tends to inhibit corrosion. Mill effluent was found to be more corrosive as compared to synthetic effluent and has been attributed to the presence of various chlorophenols. Corrosion performance of SS was observed to govern by the presence of Cr, Mo and N contents.

  13. Review of studies on corrosion of magnesium alloys

    Institute of Scientific and Technical Information of China (English)

    ZENG Rong-chang; ZHANG jin; HUANG Wei-jiu; W. DIETZEL; K. U. KAINER; C. BLAWERT; KE Wei

    2006-01-01

    This review provided some recent progress of the research on corrosion mechanisms of magnesium and its alloys and a basis for follow-on research. Galvanic corrosion,pitting corrosion,intergranular corrosion (IGC),filiform corrosion,crevice corrosion,stress corrosion cracking (SCC),and corrosion fatigue (CF) were discussed. The influence of metallurgical factors such as alloying elements,microstructure and secondary phases,processing factors such as heat treatment and weld,and environmental factors including temperature,relative humidity,solution pH values and concentration on corrosion were discussed. In particular,a mechanism of pitting corrosion caused by AlMn particles was proposed. The corrosion properties of AZ91D weld material were investigated.

  14. Inhibitor treatment program for chlorine dioxide corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Edmondson, J.G.; Holder, E.P.

    1991-11-12

    This patent describes a method of inhibiting corrosion by chlorine dioxide in oil field waterflood systems by adding a sufficient amount of a corrosion inhibiting composition. It comprises a phosphonate, a copolymer consisting of repeating units of acrylic acid/allyl hydroxy propyl sulfonate ether, and a permangante.

  15. Computer-Aided Corrosion Program Management

    Science.gov (United States)

    MacDowell, Louis

    2010-01-01

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

  16. Aircraft Integral Fuel Tank Corrosion Study

    Science.gov (United States)

    2007-11-02

    biology of Amorphoteca resinae . Materials und Organismen, 6, (3), p. 161, (1971). 8. D. Cabral. Corrosion by microorganisms of jet aircraft integral fuel...the mycelium of the fungus Hormoconis resinae in the MIC of Al alloys. Proc. XI Int. Corrosion Congress, Houston, USA, 5B, p. 3773, (1993). 14. M

  17. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-04-11

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

  18. Corrosion effects on soda lime glass

    NARCIS (Netherlands)

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

    2010-01-01

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

  19. Biobased polymers for corrosion protection of metals

    Science.gov (United States)

    Anticorrosive biobased polymers were developed in our lab. We isolated an exopolysaccharide produced by a microbe that, when coated on metal substrates, exhibited unique corrosion inhibition. Corrosion is a worldwide problem and impacts the economy, jeopardizes human health and safety, and impedes t...

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

    DEFF Research Database (Denmark)

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

    2009-01-01

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

  1. Factors affecting the corrosivity of pulping liquors

    Science.gov (United States)

    Hazlewood, Patrick Evan

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

  2. The dual role of microbes in corrosion

    NARCIS (Netherlands)

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

    2015-01-01

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

  3. Dissolution properties of cerium dibutylphosphate corrosion inhibitors

    NARCIS (Netherlands)

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

    2013-01-01

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

  4. EXTRACT OF COMBRETUM MICRANTHUM AS CORROSION ...

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Aluminum and aluminum alloys lend themselves to many engineering ... Table 1: Elemental composition of the alloy Al-Si-Mg. Element. Si. Mg. Cu. Zn. Al. Composition (wt. ..... microstructure of the control Al- Si- Mg alloy with the lowest C.R in the ... silicate as a corrosion inhibitor for iron and zinc,. Corrosion ...

  5. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    Directory of Open Access Journals (Sweden)

    Saman Hosseinpour

    2017-04-01

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

  6. Geothermal drill pipe corrosion test plan

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-12-01

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

  7. Solutions of corrosion Problems in advanced Technologies

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Karlsson, Asger

    1999-01-01

    were investigated using light optical and scanning electron microscopy. The ferritic steels suffered from corrosion mainly via material loss. The austenitic steels suffered from predominantly selective corrosion resulting in chromium depletion from the alloy. A clear trend was observed that selective...

  8. Corrosion effects on soda lime glass

    NARCIS (Netherlands)

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

    2010-01-01

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

  9. Remote computer monitors corrosion protection system

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick, A.

    Effective corrosion protection with electrochemical methods requires some method of routine monitoring that provides reliable data that is free of human error. A test installation of a remote computer control monitoring system for electrochemical corrosion protection is described. The unit can handle up to six channel inputs. Each channel comprises 3 analog signals and 1 digital. The operation of the system is discussed.

  10. Vibrational Spectroscopy in Studies of Atmospheric Corrosion

    Science.gov (United States)

    Hosseinpour, Saman; Johnson, Magnus

    2017-01-01

    Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm. PMID:28772781

  11. The dual role of microbes in corrosion

    NARCIS (Netherlands)

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

    2015-01-01

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

  12. Corrosion Behaviour of New Zr Alloys

    DEFF Research Database (Denmark)

    Tolksdorf, E.

    1974-01-01

    Corrosion studies have indicated that the most promising replacements for Zicaloy-2 are ZrCrFe, ZrVFe and probably ZrNbTa, provided they are in their optimized condition. These alloys are conventionally manufactured alloys. An internally oxidized ZrMgO alloy is even superior, from the corrosion...

  13. Electrochemical corrosion measurements on noble electrodeposits

    DEFF Research Database (Denmark)

    Christoffersen, Lasse; Maahn, Ernst Emanuel

    1998-01-01

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

  14. Toward a general psychological model of tension and suspense

    Directory of Open Access Journals (Sweden)

    Moritz eLehne

    2015-02-01

    Full Text Available Tension and suspense are powerful emotional experiences that occur in a wide variety of contexts (e.g., in music, film, literature, and everyday life. The omnipresence of tension experiences suggests that they build on very basic cognitive and affective mechanisms. However, the psychological underpinnings of tension experiences remain largely unexplained, and tension and suspense are rarely discussed from a general, domain-independent perspective. In this paper, we argue that tension experiences in different contexts (e.g., musical tension or suspense in a movie build on the same underlying psychological processes. We discuss key components of tension experiences and propose a domain-independent model of tension and suspense. According to this model, tension experiences originate from states of conflict, instability, dissonance, or uncertainty that trigger predictive processes directed at future events of emotional significance. We also discuss possible neural mechanisms underlying experiences of tension. The model provides a theoretical framework that can inform future empirical research on tension phenomena.

  15. Measuring naphthenic acid corrosion potential with the Fe powder test

    Directory of Open Access Journals (Sweden)

    Hau, J. L.

    2003-12-01

    Full Text Available Results are presented of experiments performed using a new method to measure the naphthenic acid corrosion potential. The method consists of adding pure iron powder into a small autoclave containing the crude or oil sample. The test is then performed at a given temperature for one hour, after which the oil sample is filtered and the remaining liquid is sent for iron content determination (ppm. The tests are run at 7 different temperature levels, 3 more are run as repeated tests. A best-fitted curve is drawn through these 10 experimental points and the maximum point is thus determined. This becomes the main outcome of the test and it is used to give a measure of the naphthenic acid corrosion potential. The same general trends as observed in the past using the neutralization number or TAN (Total Acid Number is obtained. However, this new test seems capable oí detecting anomalous cases where oil samples having larger values of TAN exhibit less corrosivity than others having much lower values of TAN or where they show completely different corrosivity despite having similar or the same TAN.

    Se presentan los resultados de experimentos realizados con un nuevo método para medir el potencial de corrosión por ácidos nafténicos. El método consiste en añadir hierro puro en polvo a una muestra de crudo o aceite, en un autoclave pequeño. El ensayo se realiza a una temperatura dada durante una hora; luego se filtra la muestra de aceite y el líquido filtrado se envía para medir la concentración de hierro disuelto (ppm. El ensayo se reitera para siete temperaturas diferentes y se repiten tres más para determinar su reproducibilidad. Con estos 10 puntos experimentales se dibuja la mejor curva de ajuste y se determina un máximo de hierro disuelto. Este máximo se convierte en el resultado principal del ensayo y se usa para dar una medida del potencial de corrosión por ácidos nafténicos. Se obtienen las mismas tendencias generales observadas

  16. The Corrosion and Corrosion Fatigue Behavior of Nickel Based Alloy Weld Overlay and Coextruded Claddings

    Science.gov (United States)

    Stockdale, Andrew

    The use of low NOx boilers in coal fired power plants has resulted in sulfidizing corrosive conditions within the boilers and a reduction in the service lifetime of the waterwall tubes. As a solution to this problem, Ni-based weld overlays are used to provide the necessary corrosion resistance however; they are susceptible to corrosion fatigue. There are several metallurgical factors which give rise to corrosion fatigue that are associated with the localized melting and solidification of the weld overlay process. Coextruded coatings offer the potential for improved corrosion fatigue resistance since coextrusion is a solid state coating process. The corrosion and corrosion fatigue behavior of alloy 622 weld overlays and coextruded claddings was investigated using a Gleeble thermo-mechanical simulator retrofitted with a retort. The experiments were conducted at a constant temperature of 600°C using a simulated combustion gas of N2-10%CO-5%CO2-0.12%H 2S. An alternating stress profile was used with a minimum tensile stress of 0 MPa and a maximum tensile stress of 300 MPa (ten minute fatigue cycles). The results have demonstrated that the Gleeble can be used to successfully simulate the known corrosion fatigue cracking mechanism of Ni-based weld overlays in service. Multilayer corrosion scales developed on each of the claddings that consisted of inner and outer corrosion layers. The scales formed by the outward diffusion of cations and the inward diffusion of sulfur and oxygen anions. The corrosion fatigue behavior was influenced by the surface finish and the crack interactions. The initiation of a large number of corrosion fatigue cracks was not necessarily detrimental to the corrosion fatigue resistance. Finally, the as-received coextruded cladding exhibited the best corrosion fatigue resistance.

  17. General Corrosion and Localized Corrosion of the Drip Shield

    Energy Technology Data Exchange (ETDEWEB)

    F. Hua; K. Mon

    2003-06-24

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

  18. Steam generator corrosion 2007; Dampferzeugerkorrosion 2007

    Energy Technology Data Exchange (ETDEWEB)

    Born, M. (ed.)

    2007-07-01

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

  19. Launch Pad Coatings for Smart Corrosion Control

    Science.gov (United States)

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

    2010-01-01

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

  20. Stifling of Crevice Corrosion in Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    Mon, K G; Gordon, G M; Rebak, R B

    2005-06-08

    Artificially creviced Alloy 22 (N06022) specimens may be susceptible to crevice corrosion in presence of hot chloride containing solutions. The presence of oxyanions in the electrolyte, especially nitrate, may inhibit the nucleation and growth of crevice corrosion. Constant potential tests were performed using tightly creviced specimens of Alloy 22. It was found that crevice corrosion may initiate when a constant potential above the crevice repassivation potential is applied. It was found that as the crevice corrosion nucleated, the current initially increased but later decreased. The net measured current can be converted into penetration following a power law fit of the experimental data. The average power law coefficient ''n'' was found to be 0.439, suggesting that even under constant applied potential crevice corrosion penetration is diffusion controlled.

  1. STIFLING OF CREVICE CORROSION IN ALLOY 22

    Energy Technology Data Exchange (ETDEWEB)

    K.G. Mon; G.M. Gordon; R.B. Rebak

    2005-07-01

    Artificially creviced Alloy 22 (N06022) specimens may be susceptible to crevice corrosion in presence of hot chloride containing solutions. The presence of oxyanions in the electrolyte, especially nitrate, may inhibit the nucleation and growth of crevice corrosion. Constant potential tests were performed using tightly creviced specimens of Alloy 22. It was found that crevice corrosion may initiate when a constant potential above the crevice repassivation potential is applied. It was found that as the crevice corrosion nucleated, the current initially increased but later decreased. The net measured current can be converted into penetration following a power law fit of the experimental data. The average power law coefficient ''n'' was found to be 0.439, suggesting that even under constant applied potential, crevice corrosion penetration is diffusion controlled.

  2. Microencapsulation Technologies for Corrosion Protective Coating Applications

    Science.gov (United States)

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

    2015-01-01

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

  3. Corrosion of carbon-alloyed iron aluminides

    Indian Academy of Sciences (India)

    M Sen; R Balasubramaniam; A V Ramesh Kumar

    2000-10-01

    The corrosion behaviour of two carbon-alloyed intermetallics of composition Fe–28.1Al–2.1C and Fe–27.5Al–3.7C has been studied and compared with that of binary intermetallics. Potentiodynamic polarization studies indicated that the intermetallics exhibited active–passive behaviour in an acidic solution of pH = 1, whereas they exhibited stable passivity in a buffer solution of pH 8.4. Corrosion rates were also obtained by immersion testing. The variation of corrosion rate as a function of time was similar for both the intermetallics. The variation in corrosion rate as a function of time has been explained based on the observed potentiodynamic polarization behaviour. Scanning electron microscopy of corroded surfaces indicated that the carbon-alloyed intermetallics were susceptible to galvanic corrosion, due to the presence of carbides.

  4. Laser-controllable coatings for corrosion protection.

    Science.gov (United States)

    Skorb, Ekaterina V; Skirtach, Andre G; Sviridov, Dmitry V; Shchukin, Dmitry G; Möhwald, Helmuth

    2009-07-28

    We introduce a novel and versatile approach to the corrosion protection by use of "smart" laser-controllable coating. The main advantage of the proposed technique is that one could terminate the corrosion process by very intensive healing after an appearance of corrosion centers using local laser irradiation. It is also shown that by applying a polyelectrolyte shell with noble metal particles over the mesoporous titania and silica via layer-by-layer assembly it is possible to fabricate micro- and nanoscaled reservoirs, which, being incorporated into the zirconia-organosilica matrix, are responsible for the ability of laser-driven release of the loaded materials (e.g., corrosion inhibitor). Furthermore, the resultant films are highly adhesive and could be easily deposited onto different metallic substrates. Laser-mediated remote release of incorporated corrosion inhibitor (benzotriazole) from engineered mesoporous containers with silver nanoparticles in the container shell is observed in real time on single and multicontainer levels.

  5. Modeling of Corrosion-induced Concrete Damage

    DEFF Research Database (Denmark)

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

    2013-01-01

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

  6. Fuel corrosion processes under waste disposal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Shoesmith, D.W. [Univ. of Western Ontario, Dept. of Chemistry, London, Ontario (Canada)

    1999-09-01

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

  7. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    Rebak, R B; Payer, J H

    2006-01-10

    Alloy 22 (N06022) was designed to stand the most aggressive industrial applications, including both reducing and oxidizing acids. Even in the most aggressive environments, if the temperature is lower than 150 F (66 C) Alloy 22 would remain in the passive state having particularly low corrosion rates. In multi-ionic solutions that may simulate the behavior of concentrated ground water, even at near boiling temperatures, the corrosion rate of Alloy 22 is only a few nanometers per year because the alloy is in the complete passive state. The corrosion rate of passive Alloy 22 decreases as the time increases. Immersion corrosion testing also show that the newer generation of Ni-Cr-Mo alloys may offer a better corrosion resistance than Alloy 22 only in some highly aggressive conditions such as in hot acids.

  8. Complete corrosion inhibition through graphene defect passivation.

    Science.gov (United States)

    Hsieh, Ya-Ping; Hofmann, Mario; Chang, Kai-Wen; Jhu, Jian Gang; Li, Yuan-Yao; Chen, Kuang Yao; Yang, Chang Chung; Chang, Wen-Sheng; Chen, Li-Chyong

    2014-01-28

    Graphene is expected to enable superior corrosion protection due to its impermeability and chemical inertness. Previous reports, however, demonstrate limited corrosion inhibition and even corrosion enhancement of graphene on metal surfaces. To enable the reliable and complete passivation, the origin of the low inhibition efficiency of graphene was investigated. Combining electrochemical and morphological characterization techniques, nanometer-sized structural defects in chemical vapor deposition grown graphene were found to be the cause for the limited passivation effect. Extremely fast mass transport on the order of meters per second both across and parallel to graphene layers results in an inhibition efficiency of only ∼50% for Cu covered with up to three graphene layers. Through selective passivation of the defects by atomic layer deposition (ALD) an enhanced corrosion protection of more than 99% was achieved, which compares favorably with commercial corrosion protection methods.

  9. Inhibition of aluminum corrosion using Opuntia extract

    Energy Technology Data Exchange (ETDEWEB)

    El-Etre, A.Y

    2003-11-01

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

  10. Passive Corrosion Behavior of Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    R.B. Rebak; J.H. Payer

    2006-01-20

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

  11. Numerical Study of Corrosion Crack Opening

    DEFF Research Database (Denmark)

    Thoft-Christensen, Palle; Frandsen, Henrik Lund; Svensson, Staffan

    2008-01-01

    for the corrosion crack opening. Experiments and theoretical analysis by a numerical method, FEM, support that the relation between the reduction of the reinforcement bar diameter due to corrosion and the corresponding increase in crack width for a given time interval, measured on the surface of a concrete specimen...... is proportional. More recently, the constant of proportionality, the so-called crack-corrosion index, has been studied further with respect to its dependence on the diameter of the reinforcement and the concrete cover. In the present paper the above-mentioned work is presented and extended with more realistic 3D......-models of the cracked concrete beam. The crack-corrosion index is evaluated for a variation of different parameters, i.e. bar diameter, concrete cover, crack length and type of corrosion product. This paper is an extended version of a paper by Thoft-Christensen et al. (2005) presented at the IFIP WG 7.5 Conference...

  12. Corrosion protection with eco-friendly inhibitors

    Science.gov (United States)

    Shahid, Muhammad

    2011-12-01

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

  13. Tension pneumoperitoneum complicated with tension pneumothorax in a patient with diaphragmatic eventration

    Science.gov (United States)

    Akoglu, Haldun; Coban, Erkan; Guneysel, Ozlem

    2012-01-01

    Tension pneumothorax complicating a pneumoperitoneum is a rare but known entity. However, all previously published articles report an air leak through defects in the diaphragm connecting the pneumoperitoneum and the pneumothorax. Here, the case of a 36-year-old man in whom the pneumoperitoneum acted like a tension pneumothorax because of a congenital eventration of the left diaphragm without penetration is presented. Emergency needle decompression of the abdomen was performed. A gastric ulcer that had passed through the diaphragm to the right lung was diagnosed intraoperatively. Unfortunately, the patient developed a ventricular fibrillation that remained resistant to all resuscitative efforts, and the patient died shortly afterwards. PMID:22604199

  14. Condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México

    Directory of Open Access Journals (Sweden)

    PRUDENCIA CERÓN-MIRELES

    1997-01-01

    Full Text Available Objetivo. Estudiar la asociación entre condiciones de trabajo materno y bajo peso al nacer en la Ciudad de México. Material y métodos. Se encuestaron 2 623 trabajadoras que atendieron sus partos en tres grandes hospitales de la Ciudad de México en 1992. Se obtuvo información sobre los principales factores biológicos y sociales que se asocian al bajo peso al nacer; asimismo, se determinó el estrés ocupacional utilizando el instrumento desarrollado por Karasek. Se utilizaron modelos de regresión logística para evaluar la relación de las condiciones de trabajo con el bajo peso al nacer, controlando por variables confusoras. Resultados. El bajo peso al nacer fue más alto en trabajadoras con jornadas mayores a 50 horas semanales (RM= 1.6; IC= 1.17, 2.28 y con conflictos laborales (RM= 1.5; IC= 1.0, 2.25. La falta de apoyo social tangible fue identificado como un factor de riesgo de bajo peso al nacer (RM= 1.7; IC= 1.20, 2.33. Las medidas preventivas laborales como el cambio de tareas, disminución de la jornada y las salidas por enfermedad no mostraron un efecto benéfico en el peso al nacer, a excepción de la licencia de maternidad; las madres que no la tuvieron mostraron una probabilidad 2.2 veces mayor para bajo peso al nacer (IC= 1.66, 2.93. Conclusiones. Estos hallazgos resaltan la importancia de identificar los factores de riesgo ocupacional en el embarazo..Objective. To study the association between maternal working conditions and low birth-weight in Mexico City. Material and methods. Interviews of 2 623 workers who gave birth in Mexico City hospitals during 1992 were analyzed. Information on the main biologic and social factors associated to low birth-weight was registered. Occupational stress was determined with the instrument designed by Karasek. Logistic regression models to evaluate the relationship between working conditions and low birth-weight were used, controlling by confounding variables. Results. Low birth-weight was

  15. Microbial corrosion of aluminum alloy.

    Science.gov (United States)

    Yang, S S; Chen, C Y; Wei, C B; Lin, Y T

    1996-11-01

    Several microbes were isolated from the contaminated fuel-oil in Taiwan and the microbial corrosion of aluminum alloy A356-T6 was tested by MIL-STD-810E test method. Penicillium sp. AM-F5 and Cladosporium resinac ATCC 22712 had significant adsorption and pitting on the surface of aluminum alloy, Pseudomonas acruginosa AM-B5 had weak adsorption and some precipitation in the bottom, and Candida sp. AM-Y1 had the less adsorption and few cavities formation on the surface. pH of the aqueous phase decreased 0.3 to 0.7 unit for 4 months of incubation. The corrosion of aluminum alloy was very significant in the cultures of Penicillium sp. AM-F2, Penicillium sp. AM-F5 and C. resinac ATCC 22712. The major metabolites in the aqueous phase with the inoculation of C. resinac were citric acid and oxalic acid, while succinic acid and fumaric acid were the minors.

  16. Divergence of the point tension at wetting

    Science.gov (United States)

    Abraham, D. B.; Latrémolière, F.; Upton, P. J.

    1993-07-01

    To determine the behavior of the line-point tension τ^ at the wetting transition, we consider a two-dimensional Ising model with appropriate boundary conditions and investigate suitable definitions of τ^ associated with the junction of an interface tilted with average angle θc and another lying along the substrate. Size-dependent fluctuations in the point of contact require that τ^ be defined through a convolution sum. Hence τ^~=ln(1/θc) as θc-->0 (wetting transition), which can be understood as a consequence of the entropic repulsion of the tilted part of the interface against the substrate.

  17. Surface Tension Driven Convection Experiment Completed

    Science.gov (United States)

    Jacobson, Thomas P.; Sedlak, Deborah A.

    1997-01-01

    The Surface Tension Driven Convection Experiment (STDCE) was designed to study basic fluid mechanics and heat transfer on thermocapillary flows generated by temperature variations along the free surfaces of liquids in microgravity. STDCE first flew on the USML-1 mission in July 1992 and was rebuilt for the USML-2 mission that was launched in October 1995. This was a collaborative project with principal investigators from Case Western Reserve University (CWRU), Professors Simon Ostrach and Yasuhiro Kamotani, along with a team from the NASA Lewis Research Center composed of civil servants and contractors from Aerospace Design & Fabrication, Inc. (ADF), Analex, and NYMA, Inc.

  18. Migrating corrosion inhibitor blend for reinforced concrete: Part 1 -- Prevention of corrosion

    Energy Technology Data Exchange (ETDEWEB)

    Elsener, B.; Buechler, M.; Stalder, F.; Boehni, H.

    1999-12-01

    The efficiency of a migrating corrosion inhibitor in preventing corrosion of mild steel was investigated in saturated calcium hydroxide (Ca[OH]{sub 2}) solutions and in mortar. The protective effect of the inhibitor against pitting corrosion caused by chloride attack and against uniform corrosion as a result of carbonation was determined. Results showed that high concentrations ({approx}10%) allowed the inhibition of pitting corrosion tritiation in solution containing 1 M/L sodium chloride (NaCl). However, inhibiting properties can be lost by evaporation of the volatile constituent of the inhibitor or by the precipitation of the nonvolatile fraction of the inhibitor in presence of calcium ions. Addition of the inhibitor blend to mortar yielded a retardation of the corrosion initiation in the case of chloride-induced corrosion, but o significant reduction in corrosion rate. No effect was found in carbonated samples, and no influence on the corrosion rate was detected. Additionally, the estimation of the extent of the retarding effect on corrosion initiation on real structures was difficult, as the inhibitor was found to evaporate from the mortar. This evaporation resulted in a loss of inhibiting properties. Hence, the long-term efficiency of the inhibitor could not be guaranteed.

  19. Sistema biosensor de bajo coste para el diagnóstico de malaria

    OpenAIRE

    HERNÁNDEZ DÍAZ, SARA

    2015-01-01

    [ES] Aproximadamente la mitad de la población mundial corre el riesgo de contraer la malaria, y se calcula que en 2010 hubo 219 millones de casos. Detener y comenzar a reducir, en 2015, la incidencia de la malaria y otras enfermedades graves es una de las metas de uno de los Objetivos de Desarrollo del Milenio. La prevención y control de la infección es el modo de abordar esta meta. Estas acciones se ven facilitadas especialmente en los países de bajos ingresos, si se dispone de herramientas ...

  20. Viabilidad en semillas de Nothofagus pumilio bajo diferentes condiciones de almacenamiento

    OpenAIRE

    Mansilla, Paula Romina; Moretto, Alicia Susana; Pancotto, Veronica Andrea; Vrsalovic, Jazmin; Oro, N.; Escobar, Julio Martin

    2015-01-01

    Nothofagus pumilio es la especie dominante del ecosistema boscoso de Tierra del Fuego, se reproduce principalmente por semillas y presenta ciclos de semillazón cada 6-8 años aproximadamente. No forma bancos de semillas permanentes, pero en su lugar presenta extensos bancos de plántulas. El objetivo de este trabajo fue evaluar la viabilidad de semillas de Nothofagus pumilio bajo 2 condiciones de temperatura de almacenamiento: ambiente (21ºC) y heladera (5ºC), en el tiempo: a 5 meses y 2 años d...

  1. Entrenamiento en configuraciones vinculares de familia y pareja bajo la modalidad terapeuta-coterapeuta

    OpenAIRE

    Marta Cecilia Roldán Henao; Sandra Helena Castaño Montoya; Mónica Schnitter Castellanos

    2012-01-01

    Objetivo. El estudio es del tipo investigación-intervención bajo la modalidad terapeuta-coterapeuta,orientado a entrenar a los/as estudiantes, en atención a familias y parejas. Método. Se utilizó la metodología cualitativa acción participante, en la vertiente llamada experiencial. Participaron en el estudio dos profesionales, psicólogas clínicas y 6 estudiantes de pregrado de Psicología de últimos semestres. Resultados. Se recogieron las experiencias vividas mediante la fundamentación e imple...

  2. LA FORMACIÓN DOCENTE BAJO UNA CONCEPTUALIZACION COMPREHENSIVA Y UN ENFOQUE POR COMPETENCIAS

    OpenAIRE

    Barraza,Arturo

    2007-01-01

    El presente trabajo se compone de tres partes: en una primera se aborda la formación profesional por competencias para hacer ver su principal limitación, la cual justifica y da origen al trabajo; en una segunda se realiza una discusión conceptual sobre el término formación para llegar a un concepto que guíe la reelaboración que se pretende hacer, y en una tercera se presenta una propuesta para conceptualizar la formación profesional de los docentes bajo un enfoque por competencias.

  3. Producción de jitomate (Solanum lycopersicum L.) bajo condiciones protegidas e hidroponia en Tabasco.

    OpenAIRE

    2012-01-01

    Se realizaron tres experimentos; dos fueron conducidos de noviembre de 2008 a abril de 2009 y uno más de agosto de 2009 a febrero de 2010 con la finalidad de generar información en el manejo del cultivo de jitomate (Solanum lycopersicum L.), bajo condiciones protegidas e hidroponía para el estado de Tabasco. Se plantearon los siguientes objetivos: 1) Conocer la respuesta a densidades de población en plantas conducidas con diferentes números de tallos, 2) Establecer la mejor dosis de aplicació...

  4. Mineralogía del Prospecto Bajo Agua Tapada, Catamarca, Argentina

    OpenAIRE

    Gimeno Torrente, Domingo; Carrazana, Ariana; Bruna Novillo, Julio; Fernández Turiel, José Luis

    2011-01-01

    El objeto de este trabajo es la definición por vez primera de las asociaciones minerales (menas productivas y paragénesis de alteración hidrotermal)del llamado Prospecto Bajo Agua Tapada, de cara a la realización de una primera valoración de su interés; este trabajo se ha realizado tanto mediante mapeo y muestreo superficial como tras el estudio (mineralógico y geoquímica)de unos 2800 m de sondeos realizados a testigo contínuo.

  5. Sistemas urbanos alternativos para el biotratamiento y reciclaje de aguas residuales en colonias de bajos ingresos

    OpenAIRE

    Jan Bazant

    2003-01-01

    En México, los gobiernos locales no cuentan con suficientes recursos financieros ni reservas hídricas para extender las redes de infraestructura hacia asentamientos de población de bajos ingresos que atomizada y desordenadamente van ocupando las periferias de las ciudades. Se plantea en este artículo un “sistema urbano alternativo” que proporcione soluciones técnicamente viables al problema del abastecimiento de agua en las periferias. La canalización y tratamiento de aguas residuales por med...

  6. Violencia intrafamiliar y social bajo la influencia del alcohol y las drogas

    OpenAIRE

    Salazar, Edy; Pontificia Universidad Javeriana

    2011-01-01

    El objetivo de este artículo es describir la frecuencia y la magnitud de la violencia social e intrafamiliar (contra la mujer) por su pareja bajo efectos del alcohol y las drogas y las implicaciones emocionales de estos comportamientos en la mujer. Los resultados obtenidos, mediante una entrevista estructurada y tres sesiones de grupos focales, reportaron un grupo de mujeres entre 15 y 35 años de edad, solas o con algún tipo de unión de pareja, nivel de escolaridad secundaria, amas de casa, y...

  7. CAMBIOS EN LAS RESERVAS DE CARBONO ORGÁNICO DEL SUELO BAJO DIFERENTES COBERTURAS

    OpenAIRE

    José I. Bojórquez Serrano; Lucía A. Castillo Pacheco; Alberto Hernández Jiménez; Juan D. García Paredes; Alberto Madueño Molina

    2015-01-01

    Las reservas de carbono orgánico en los suelos (COS) y sus cambios en el tiempo son un tema ambiental de actualidad, asimismo las pérdidas de COS que ocurren con la conversión de ecosistemas naturales a agrosistemas, contribuyen con emisiones a la atmósfera, al calentamiento global y el cambio climático. El objetivo de este trabajo fue estudiar los cambios en las reservas de COS bajo diferentes coberturas de la cuenca del río Mololoa, Nayarit, México. El análisis de los cambios se rea...

  8. Análisis del bajo peso en la atención primaria

    Directory of Open Access Journals (Sweden)

    Miguel Lugones Botell

    1995-08-01

    Full Text Available Se realiza un estudio retrospectivo de algunos aspectos relacionados con la atención prenatal de las gestantes y su análisis correspondiente, que tuvieron recién nacidos de bajo peso en el período comprendido entre 1988 y 1991, ambos inclusive. Se concluye que los principales factores relacionados con éste fueron: nuliparidad, madre trabajadora, poca ganancia de peso en el embarazo y entre las afecciones asociadas con la gestación encontramos la amenaza de aborto, la anemia y la enfermedad hipertensiva del embarazo, entre las más frecuentes.

  9. Atmospheric Corrosivity at Australian and Overseas Airbases and Airports

    Science.gov (United States)

    2014-07-01

    protective coating systems and corrosion inhibitor treatments deteriorate and become less effective. The CLIMAT environmental corrosion test has...UNCLASSIFIED UNCLASSIFIED Atmospheric Corrosivity at Australian and Overseas Airbases and Airports J C Bitcon Maritime...Division Defence Science and Technology Organisation DSTO-TN-1320 ABSTRACT Atmospheric corrosivity at 25 airbases and airports in Australia

  10. 49 CFR 193.2631 - Internal corrosion control.

    Science.gov (United States)

    2010-10-01

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

  11. 49 CFR 192.475 - Internal corrosion control: General.

    Science.gov (United States)

    2010-10-01

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

  12. 46 CFR 154.412 - Cargo tank corrosion allowance.

    Science.gov (United States)

    2010-10-01

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

  13. 49 CFR 193.2627 - Atmospheric corrosion control.

    Science.gov (United States)

    2010-10-01

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

  14. EVALUACION DE LA RESISTENCIA A LA CORROSION DEL SISTEMA PRIMER EPOXICO RICO EN ZINC/ACABADO POLISILOXANO POR MEDIO DE ESPECTROSCOPIA DE IMPEDANCIA ELECTROQUIMICA

    Directory of Open Access Journals (Sweden)

    ANDRES ALBERTO GUZMAN ROSAS

    2011-01-01

    Full Text Available En este trabajo fue estudiado el sistema primer epoxico rico en zinc / acabado polisiloxano aplicado sobre laminas de acero al carbono laminado en caliente y sometido a camaras de corrosion acelerada (inmersion total, niebla salina, ciclo de corrosion y prohesion por un periodo de hasta 5000 horas. Las probetas bajo estudio se evaluaron cada 20 dias por medio de espectroscopia de impedancia electroquimica y al final de la prueba se realizaron chequeos visuales y microscopia optica para ver la morfologia de la interface metal-recubrimiento y microespectroscopia Raman para identificar la presencia de posibles productos de corrosion. Los resultados de impedancia fueron simulados por medio de circuitos electricos equivalentes. Para el sistema se encontraron modulos de impedancia del orden de 1011 ¿.cm2 en prohesion, 1010 ¿.cm2 en ciclo de corrosion, 109 ¿.cm2 tanto niebla salina como en las inmersiones totales (NaCl 10-2M y Na2SO4 10-2M. Este sistema tuvo durante el tiempo de pruebas un comportamiento excelente con altas resistencias de pelicula y de transferencia de carga y bajas capacitancias de pelicula y de doble capa.

  15. Corrosion damage evolution and residual strength of corroded aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Youhong Zhang; Guozhi Lv; Hui Wang; Bomei Si; Yueliang Cheng

    2008-01-01

    The LY12CZ aluminum alloy specimens were eurroded under the conditions of different test temperatures and exposure durations. After corrosion exposure, fatigue tests were performed. Scanning electron microscopy and optical microscope analyses on corrosion damage were carried out. The definition of surface corrosion damage ratio was provided to describe the extent of surface corrosion damage. On the basis of the measured data sets of the corrosion damage ratio, the probabilistic model of corrosion damage evolution was built. The corrosion damage decreased the fatigue life by a factor of about 1.25 to 2.38 and the prediction method of residual strength of the corroded structure was presented.

  16. A Calculation Model for Corrosion Cracking in RC Structures

    Institute of Scientific and Technical Information of China (English)

    Xu Gang; Wei Jun; Zhang Keqiang; Zhou Xiwu

    2007-01-01

    A novel calculation model is proposed aiming at the problem of concrete cover cracking induced by reinforcement corrosion. In this article, the relationship between the corrosion depth of the bar and the thickness of the rust layer is established. By deducing the radial displacement expression of concrete, the formula for corrosion depth and corrosion pressure before cracking is proposed. The crack depth of cover in accordance with the maximum corrosion pressure is deduced; furthermore, the corrosion depth and corrosion pressure at the cracking time are obtained. Finally, the theoretical model is validated by several experiments, and the calculated values agree well with the experiment results.

  17. Study on Localized Corrosion Cracking of Alloy 600 using EN-DCPD Technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yeonju; Kim, Sungwoo; Kim, Hongpyo; Hwang, Seongsik [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-02-15

    The object of this work is to establish an electrochemical noise(EN) measurement technique combined with a direct current potential drop(DCPD) method for monitoring of localized corrosion cracking of nickel-based alloy, and to analyze its mechanism. The electrochemical current and potential noises were measured under various conditions of applied stress to a compact tension specimen in a simulated primary water chemistry of a pressurized water reactor. The amplitude and frequency of the EN signals were evaluated in both time and frequency domains based on a shot noise theory, and then quantitatively analyzed using statistical Weibull distribution function. From the spectral analysis, the effect of the current application in DCPD was found to be effectively excluded from the EN signals generated from the localized corrosion cracking. With the aid of a microstructural analysis, the relationship between EN signals and the localized corrosion cracking mechanism was investigated by comparing the shape parameter of Weibull distribution of a mean time-to-failure.

  18. Corrosion inhibitors for intermediate cooling systems

    Energy Technology Data Exchange (ETDEWEB)

    Falk, I.; Suhr, L.

    1985-04-01

    The selected inhibitors were tested for heat and radiation stability and corrosion protection on the bench scale. Based on the results from these tests two of the products were selected, Bycoguard 81 and Bycoguard MP4S for continuing corrosion tests in an autoclave loop at 90 degrees C and 120 degrees C. Oxygen saturated deionized water with an addition of 1 ppm chloride was recirculated in the loop. Samples of copper and carbon steel were exposed to the water in the autoclave for periods up to 10 weeks. The purpose of this project was to find a substitute for hydrazine and chromates. Besides good corrosion protection qualities the toxic and environmental effect of the inhibitors should be minimal. The investigation has shown that the copper inhibitor BTA (benzotriazole) loses its corrosion protection qualities at a water temperature of 120 degrees C. The protection effects at 90 degrees C were satisfactory for both of the materials. The corrosion rates measured were 0.01 mm/y or less for the copper and carbon steel samples. The environment in the autoclave during the testing was more corrosive than is to be found in intermediate cooling systems. Due to the low corrosion rates measured the two inhibitors are to be recommended as alternatives to hydrazine and chromates.

  19. Mesoporous silica nanoparticles for active corrosion protection.

    Science.gov (United States)

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

    2011-03-22

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

  20. Marine atmospheric corrosion of carbon steels

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-01

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

  1. Thermally Insulating, Kinematic Tensioned-Fiber Suspension

    Science.gov (United States)

    Voellmer, George M.

    2004-01-01

    A salt pill and some parts of a thermally insulating, kinematic suspension system that holds the salt pill rigidly in an adiabatic-demagnetization refrigerator (ADR) is presented. "Salt pill" in this context denotes a unit comprising a cylindrical container, a matrix of gold wires in the container, and a cylinder of ferric ammonium alum (a paramagnetic salt) that has been deposited on the wires. The structural members used in this system for both thermal insulation and positioning are aromatic polyamide fibers (Kevlar(R) or equivalent) under tension. This suspension system is designed to satisfy several special requirements to ensure the proper operation of the ADR. These requirements are to (1) maintain the salt pill at a specified position within the cylindrical bore of an electromagnet; (2) prevent vibrations, which would cause dissipation of heat in the salt pill; and (3) minimize the conduction of heat from the electromagnet bore and other neighboring objects to the salt pill; all while (4) protecting the salt pill (which is fragile) against all tensile and bending loads other than those attributable to its own weight. In addition, the system is required to consist of two subsystems -- one for the top end and one for the bottom end of the salt pill -- that can be assembled and tensioned separately from each other and from the salt pill, then later attached to the salt pill.

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

    Directory of Open Access Journals (Sweden)

    Marko Chigondo

    2016-01-01

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

  3. Novel Corrosion Sensor for Vision 21 Systems

    Energy Technology Data Exchange (ETDEWEB)

    Heng Ban

    2005-12-01

    Advanced sensor technology is identified as a key component for advanced power systems for future energy plants that would have virtually no environmental impact. This project intends to develop a novel high temperature corrosion sensor and subsequent measurement system for advanced power systems. Fireside corrosion is the metal loss caused by chemical reactions on surfaces exposed to the combustion environment. Such corrosion is the leading mechanism for boiler tube failures and has emerged to be a significant concern for current and future energy plants due to the introduction of technologies targeting emissions reduction, efficiency improvement, or fuel/oxidant flexibility. Corrosion damage can lead to catastrophic equipment failure, explosions, and forced outages. Proper management of corrosion requires real-time indication of corrosion rate. However, short-term, on-line corrosion monitoring systems for fireside corrosion remain a technical challenge to date due to the extremely harsh combustion environment. The overall objective of this project is to develop a technology for on-line corrosion monitoring based on a new concept. This objective is to be achieved by a laboratory development of the sensor and instrumentation, testing of the measurement system in a laboratory muffle furnace, and eventually testing the system in a coal-fired furnace. The initial plan for testing at the coal-fired pilot-scale furnace was replaced by testing in a power plant, because the operation condition at the power plant is continuous and more stable. The first two-year effort was completed with the successful development sensor and measurement system, and successful testing in a muffle furnace. Because of the potential high cost in sensor fabrication, a different type of sensor was used and tested in a power plant burning eastern bituminous coals. This report summarize the experiences and results of the first two years of the three-year project, which include laboratory

  4. Velocidad de crecimiento de grietas por corrosión bajo tensión en soldaduras disímiles

    Directory of Open Access Journals (Sweden)

    Fernández, María del Pilar

    2000-02-01

    Full Text Available Dissimilar welds, used to join different sections in light water reactors, are potentially susceptible to stress corrosion cracking (SCC in aqueous mediums characteristic of nuclear plants. However, the study of these welds has been limited to evaluating the weld material susceptibility in these mediums. Little scarce data are available on crack growth rates due, fundamentally, to inadequate testing techniques. In order to address this lack of information the crack growth rate at the interface of ferritic SA533B-1 alloy and alloy 1-82, in a dissimilar weld (SA533B-1/I-82/316L, was studied. Experiments were conducted in water at 288 °C, 8 ppm of O2 and 1 μS/cm conductivity.

    Las soldaduras disímiles, que son utilizadas para unir diferentes partes en los reactores de agua ligera, son potencialmente susceptibles de experimentar corrosión bajo tensión (SCC en los medios acuosos característicos de las plantas nucleares. Sin embargo, el estudio de estas soldaduras ha estado limitado a evaluar en dichos medios la susceptibilidad a SCC de los materiales que componen las mismas por separado, existiendo pocos datos de velocidad de crecimiento de grietas debido fundamentalmente a la falta de estandarización de este tipo de ensayos. En este trabajo se ha pretendido determinar la velocidad de crecimiento de grietas en la interfase formada por el acero ferrítico SA533B-1y la aleación I-82 dentro de la soldadura disímil compuesta por el acero SA533B-1/I-82/316L en unas condiciones de química del agua correspondientes a 8 ppm de O2, una conductividad de 1 μS/cm y a una temperatura de 288 °C.

  5. Slurry Chemical Corrosion and Galvanic Corrosion during Copper Chemical Mechanical Polishing

    Science.gov (United States)

    Kondo, Seiichi; Sakuma, Noriyuki; Homma, Yoshio; Ohashi, Naofumi

    2000-11-01

    Copper (Cu) corrosion during chemical mechanical polishing (CMP) was controlled in order to improve the Cu damascene interconnect process. Slurry chemical corrosion was found to be enhanced when the slurry was diluted by deionized (DI) water during rinsing just after CMP@. Since the corrosion inhibitor, benzotriazole (BTA), reduces the Cu removal rate, adding it to the rinse solution prevents chemical corrosion more effectively than adding it to the slurry. On the other hand, galvanic corrosion occurs at the interface between Cu and the barrier metal, and it can be prevented by selecting appropriate barrier metals. Because the difference between the electrochemical potentials of Cu and the barrier metal is small in the slurry, refractory metals such as Ta, TaN, and TiN were found to be appropriate barrier metals. On the other hand, W, WN, and Ti have large potential differences, so galvanic corrosion was clearly observed when Cu/W damascene interconnects were fabricated.

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

    Energy Technology Data Exchange (ETDEWEB)

    BOOMER, K.D.

    2007-08-21

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

  7. Theoretical and experimental study on surface tension and dynamic surface tension of aqueous lithium bromide and water with additive

    Institute of Scientific and Technical Information of China (English)

    程文龙; 陈则韶; 秋泽淳; 胡芃; 柏木孝夫

    2003-01-01

    The surface tensions of water and aqueous lithium bromide (LiBr) with 2-ethyl-1-hexa- nol (2EH) and 1-octanol were measured using Wilhelmy plate method, and the oscillation of surface tension under the open condition for LiBr solution was observed. The dynamic surface tensions of water and LiBr solution in the presence of the 2EH and 1-octanol vapor were measured in this paper. The results showed that the additives vapor could obviously affect surface tension. For water, the dynamic surface tension was also affected by the mass of the tested liquid; however, for LiBr solution, the dynamic surface tension was not related to the mass of the tested solution. According to the experimental results, the hypothesis that surface tension varies linearly with the surface excess concentration is advanced, which could overcome the limit of Gibbs equation. The equations of surface absorption and desorption are modified, the units of the adsorption coefficient and desorption coefficient are unified; the effects of the liquid and vapor of additive on the surface tension are unified; the theoretical relations of the static surface tension and dynamic surface tension with the relative contents of the liquid and vapor of additive are obtained under the combined actions of them; the theoretical equations are validated by the experiments results.

  8. Tension-type headache: pain, fatigue, tension, and EMG responses to mental activation.

    Science.gov (United States)

    Bansevicius, D; Westgaard, R H; Sjaastad, O M

    1999-06-01

    Twenty patients with tension-type headache (14 chronic and 6 episodic) and 20 group-matched controls were selected for this study. They participated in a 1-hour, complex, two-choice, reaction-time test, as well as 5-minute pretest and 20-minute posttest periods. Subjects reported any pain in the forehead, temples, neck, and shoulders, as well as any feelings of fatigue and tension during the pretest, and every 10 minutes during the test and posttest by visual analog scales. Superficial electromyography was recorded simultaneously from positions representing the frontal and temporal muscles, neck (mostly splenius), and trapezius muscles. The location of pain corresponded to the position of the electrodes, but extended over a larger area. The test provoked pain in the forehead, neck, and shoulders of patients, i.e., pain scores from these regions increased significantly during the test. The pain scores continued to increase posttest. In patients, the EMG response of the trapezius (first 10 minutes of the test) was elevated relative to pretest. In controls, only the frontal muscles showed an EMG test response. Patients showed significantly higher EMG responses than controls in the neck (whole test period) and trapezius (first 10 minutes of the test period). There were significant differences in pain and fatigue scoring between patients and controls in all three periods and in tension scoring posttest. Fatigue correlated with pain, with increasing significance for all locations examined, while tension was mainly associated with the neck pain. The meaning of the variables "tension" and "fatigue" in headache, and their association with recorded muscle activity in various regions is discussed. The EMG response of the trapezius muscle to the test is discussed in comparison with similar responses observed in patients with other pain syndromes.

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

    Science.gov (United States)

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

    2016-06-01

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

  10. Assessment of Commercial Corrosion Inhibiting Admixtures for Reinforced Concrete

    OpenAIRE

    Brown, Michael Carey

    1999-01-01

    Corrosion of reinforcing steel in concrete exposed to chloride-laden environments is a well-known and documented phenomenon. The need for cost effective systems for protection against corrosion has become increasingly clear since the first observations of severe corrosion damage to interstate bridges in the 1960's. As one potential solution to the mounting problem of corrosion deterioration of structures, corrosion-inhibiting admixtures have been researched and introduced into service. ...

  11. A simple method for the design of tension structures combining topological mapping and nonlinear structural analysis

    Directory of Open Access Journals (Sweden)

    Jurado-Piña, R.

    2014-12-01

    Full Text Available When designing a tension structure the shape is not known at the beginning of the process. Form-finding methods allow the designer to obtain an initial shape from given boundary conditions. Several form-finding methods for tension structures are already available in the technical literature; all of them posses certain limitations and drawbacks and no single method is optimal for all problems. The engineer may select the proper combination of methods best suited to the designer’s needs. In this paper it is proposed a combined method to achieve satisfactory equilibrium configurations for fabric tension structures. The force density method (FDM implemented with topological mapping (TM is used as a search engine for the preliminary design, and a procedure that employs nonlinear structural analysis is proposed for final refinement of the initial equilibrium configuration hence allowing the use of the same analysis tool for both refinement of the solution and analysis under loading.Al diseñar una estructura tensada la forma inicial es normalmente desconocida. Los métodos de búsqueda de forma permiten al ingeniero obtener una geometría inicial dadas unas condiciones de contorno. Existen diferentes métodos de búsqueda de formas de equilibrio, pero todos tienen limitaciones y no existe uno único óptimo para cualquier tipo de problema. El ingeniero debe elegir la combinación de métodos que mejor se adapte a sus necesidades. En este artículo se propone un método combinado para generar configuraciones de equilibrio satisfactorias en estructuras tensadas. Como motor de búsqueda para el diseño preliminar se emplea el método de las densidades de fuerza (FDM implementado con mallado en topología (TM, y se propone un procedimiento basado en análisis no lineal de estructuras para el refinamiento de la configuración inicial de equilibrio, permitiéndose así el empleo de las mismas herramientas tanto para el refinamiento de la solución inicial

  12. A Localised Corrosion Cell for Industrial Applications

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  13. Numerical Modeling of Weld Joint Corrosion

    Science.gov (United States)

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

    2016-03-01

    A numerical model is presented in this work that predicts the corrosion rate of weld joint. The model is able to track moving boundary of the corroding constituent of weld joint. The corrosion rates obtained from the model are compared with those estimated from mixed potential theory and two experimental techniques, namely immersion test and constant potential polarization test. The corrosion rate predicted using the model is within 10% of the estimate from the mixed potential theory, within 20% of that got from the immersion experiment and within 10% of that got from the constant potential polarization experiment for weld joint.

  14. Numerical modelling of corrosion - Theoretical backgrounds -

    Energy Technology Data Exchange (ETDEWEB)

    Warkus, J.; Raupach, M. [ibac, RWTH Aachen (Germany); Gulikers, J. [Ministry of Transport, Rijkswaterstaat, Bouwdienst, Utrecht (Netherlands)

    2006-08-15

    During recent years research projects with different approaches have been carried out to develop models which are suitable to assess the metal removal rate in case of reinforcement corrosion. Some of them are based on empirical methods and correlate the corrosion rate to parameters like concrete resistivity, temperature and relative humidity. Another type of model is based on a quantification of the ongoing electrochemical processes. In this paper the theoretical backgrounds and mathematical descriptions of reinforcement corrosion with regard to a numerical modelling are presented and discussed. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

  15. Corrosion resistant storage container for radioactive material

    Science.gov (United States)

    Schweitzer, Donald G.; Davis, Mary S.

    1990-01-01

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

  16. A Localised Corrosion Cell for Industrial Applications

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  17. Container assessment: corrosion study of HLW container materials. Quarterly progress report, July-September 1981. Volume 1, No. 3

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, T M; Soo, P

    1982-01-01

    Work has been started on the corrosion and hydrogen embrittlement behavior of commercially pure titanium (ASTM Grade 2), TiCode-12 (ASTM Grade 12), and OFHC copper, which are primary candidate materials for high level waste containers. The test environment used is a simulated brine solution typical of bedded salt at 150 C or room temperature. The immersion test results for these materials are in reasonable agreement with previous screening test results of Sandia National Laboratory; electron beam welded titanium and TiCode-12 samples show higher corrosion rates than the non-welded samples. To understand the difference between titanium and TiCode-12 in uniform and crevice corrosion, electrochemical tests were performed. While the initial repassivation behavior is similar in terms of charge density transfer after scratching tests in 1 M HCl solution at 80 C, titanium shows an active peak in polarization curves in brine at room temperature while TiCode-12 does not. Also, the open circuit corrosion potential of TiCode-12 is about 300 mV more anodic than that of titanium in 0.1 M HCl plus 0.9 M KCl solution at 85 C. Slow strain rate embrittlement and impact embrittlement have been observed in cathodically hydrogen charged commercially pure titanium and TiCode-12 in tension and buckling tests. C-ring and U-bend specimens of titanium and TiCode-12 have been designed and a slow strain rate test machine is being built to study stress corrosion cracking. Alternating Current Impedance and Scanning Reference Electrode Techniques are ready for pitting studies. For the study of radiation-induced corrosion, an irradiation cell was set up in the gamma pool to estimate quantitatively the oxidants as well as hydrogen produced by the gamma radiation in the brine solutions. 35 refs., 18 figs., 5 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

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

  19. Corrosion Effects on the Strength Properties of Steel Fibre Reinforced Concrete Containing Slag and Corrosion Inhibitor

    OpenAIRE

    Sivakumar Anandan; Sounthararajan Vallarasu Manoharan; Thirumurugan Sengottian

    2014-01-01

    Corrosion in steel can be detrimental in any steel rebar reinforced concrete as well as in the case of steel fibre reinforced concrete. The process of corrosion occurring in steel fibre incorporated concrete subjected to corrosive environment was systematically evaluated in this study. Concrete specimens were prepared with steel fibre inclusions at 1.5% Vf (volume fraction) of concrete and were added in slag based concrete (containing manufactured sand) and replaced with cement at 20%, 40%, ...

  20. THE CONSTRUCTION AND CONTESTATION OF ISLAMIC IDENTITY OF THE BAJO PEOPLE IN WAKATOBI ISLANDS, SOUTH EAST SULAWESI, INDONESIA

    Directory of Open Access Journals (Sweden)

    Benny Baskara

    2014-02-01

    Full Text Available On the one one hand, the Bajo people are well-known as ‘the sea people’ who have their own indigenous belief system – belief in the Lord of the Sea. On the other hand, they also acknowledge themselves as Muslims. Thus, the religious identity of the Bajo people reflects a unique combination of Islamic teachings and their indigenous beliefs. This unique combination is not only expressed in their religious life, in their rituals and worship practices, but also in the values found in their customary practices (adat as a guiding system for their life. This paper examines the construction and contestation of the religious identity of the Bajo people, especially how they construct their identities in relation to their natural, social, and religious environments. The contestation of the Bajo religious identity covers three aspects: the contestation of the Islam of ‘the sea people’ against the Islam of ‘the land people’, the contenstation of the ‘official’ Islam against the ‘traditional’ Islam, and the challenges of modernity, especially the commodification of the Bajo religious expressions. This contestation, in turn, reconstructs their religious identity into a more adaptive one.