Academic literature on the topic 'Iron-based model alloys'
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Journal articles on the topic "Iron-based model alloys"
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Sugano, R., K. Morishita, and A. Kimura. "Helium Accumulation Behavior in Iron Based Model Alloys." Fusion Science and Technology 44, no. 2 (September 2003): 446–49. http://dx.doi.org/10.13182/fst03-a375.
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Lech-Grega, Marzena, and Sonia Boczkal. "Iron Phases in Model Al-Mg-Si-Cu Alloys." Materials Science Forum 674 (February 2011): 135–40. http://dx.doi.org/10.4028/www.scientific.net/msf.674.135.
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Iron phases present in alloys from the 6xxx series affect the workability behaviour of these alloys. Iron in these alloys occurs in the form of intermetallic phases and AlFe, α-AlFeSi, β- AlFeSi eutectics. The homogenisation treatment is carried out to induce the transformation of phase into phase The aim of the studies was EDX and EBSD analysis by scanning microscopy of iron phases present in model alloys based on 6061 system, characterised by the silicon-iron ratio Si/Fe=0,5 and 1, examined in as-cast condition and after homogenisation, followed by a comparison of the detected phases with phases present in industrial ingots. In 6061 alloy, copper in the amount of 0,4wt.% occurred in the solid solution of aluminium. The EDX analysis proved that copper atoms were embedded also in iron precipitates, and scarce phases of an AlxCuy type were being formed. Different content of magnesium in the examined alloys (0,8 and 1,2wt.%) affected not only the quantitative content of Mg2Si phases, but also the presence of AlFe phases in alloy with small content of Si (0,4wt.%) and high content of Mg (1,2wt.%).
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Le, Cao Dang, Konstanchin D. Savelyev, and Valeri Mikhailovich Golod. "Structure Diagnostic of Iron-Based Out-of-Peritectic Alloys during Nonequilibrium Crystallization." Key Engineering Materials 822 (September 2019): 3–10. http://dx.doi.org/10.4028/www.scientific.net/kem.822.3.
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The effect of the contribution of basic components (silicon, manganese, chromium, and nickel) in multicomponent iron-based alloys on critical point position of the peritectic reaction was studied by using the POLYTHERM software package. Obtained temperature and concentration values of critical points of peritectic transformation, depending on the content of iron-based alloy components (Si, Mn, Cr, Ni) were used to build summary equations, represented the change in temperature and concentration of critical points by variation of binary, ternary and quaternary alloy composition. Investigation of nonequilibrium crystallization of out-of-peritectic casting steels was performed by using a system of computer models describing thermodynamic, thermophysical, diffusion and capillary processes during solidification under coalescence of dendritic branches. The nonequilibrium crystallization regime was specified by suppression of diffusion in the solid phase, reflected by adding the inverse diffusion parameter to the system of the computer model. The application of these computer models not only allows to make calculations of the temperature course, the solid phase fraction and the composition of the components in the liquid phase but also the calculation of secondary arm spacing during crystallization with taking into account the coalescence process.
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Taylor, Christopher D. "Cohesive Relations for Surface Atoms in the Iron-Technetium Binary System." Journal of Metallurgy 2011 (October 16, 2011): 1–8. http://dx.doi.org/10.1155/2011/954170.
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Iron-technetium alloys are of relevance to the development of waste forms for disposition of radioactive technetium-99 obtained from spent nuclear fuel. Corrosion of candidate waste forms is a function of the local cohesive energy () of surface atoms. A theoretical model for calculating is developed. Density functional theory was used to construct a modified embedded atom (MEAM) potential for iron-technetium. Materials properties determined for the iron-technetium system were in good agreement with the literature. To explore the relationship between local structure and corrosion, MEAM simulations were performed on representative iron-technetium alloys and intermetallics. Technetium-rich phases have lower , suggesting that these phases will be more noble than iron-rich ones. Quantitative estimates of based on numbers of nearest neighbors alone can lead to errors up to 0.5 eV. Consequently, atomistic corrosion simulations for alloy systems should utilize physics-based models that consider not only neighbor counts, but also local compositions and atomic arrangements.
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Kumar Singla, Yogesh, DK Dwivedi, and Navneet Arora. "Modeling the impact–sliding wear characteristics of rare earth additive iron-based hardfacing alloys." Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology 231, no. 11 (March 10, 2017): 1486–99. http://dx.doi.org/10.1177/1350650117699302.
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This paper presents a systematic study of the effect of the cerium oxide content on the mechanical, microstructural and tribological properties of iron-based alloys. The results indicate that the microstructure of the hardfaced alloys is mainly composed of austenite, MC and M7C3 carbides. The primary austenite grain size was refined at first and then coarsened with the increase of the rare earth oxide additions. Meanwhile, the hardness of the hardfacing alloy was also increased. The increased area fraction of carbides was found to be beneficial for enhanced wear resistance. A statistical regression model was developed and verified with a number of test cases in order to evaluate the adequacy of the model. The optimal amount of rare earth was found to be less than 6 wt.%; below this composition, the microstructural, mechanical and tribological properties were excellent.
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Atulasimha, Jayasimha, Alison B. Flatau, and Eric Summers. "Characterization and energy-based model of the magnetomechanical behavior of polycrystalline iron–gallium alloys." Smart Materials and Structures 16, no. 4 (July 5, 2007): 1265–76. http://dx.doi.org/10.1088/0964-1726/16/4/039.
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Fourlakidis, Vasilios, Ilia Belov, and Attila Diószegi. "Strength Prediction for Pearlitic Lamellar Graphite Iron: Model Validation." Metals 8, no. 9 (August 31, 2018): 684. http://dx.doi.org/10.3390/met8090684.
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The present work provides validation of the ultimate tensile strength computational models, based on full-scale lamellar graphite iron casting process simulation, against previously obtained experimental data. Microstructure models have been combined with modified Griffith and Hall–Petch equations, and incorporated into casting simulation software, to enable the strength prediction for four pearlitic lamellar cast iron alloys with various carbon contents. The results show that the developed models can be successfully applied within the strength prediction methodology along with the simulation tools, for a wide range of carbon contents and for different solidification rates typical for both thin- and thick-walled complex-shaped iron castings.
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Dolatabadi, Neda, Moslem Shahverdi, Mehdi Ghassemieh, and Masoud Motavalli. "RC Structures Strengthened by an Iron-Based Shape Memory Alloy Embedded in a Shotcrete Layer—Nonlinear Finite Element Modeling." Materials 13, no. 23 (December 3, 2020): 5504. http://dx.doi.org/10.3390/ma13235504.
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Shape memory alloys (SMAs) have been widely used in civil engineering applications including active and passive control of structures, sensors and actuators and strengthening of reinforced concrete (RC) structures owing to unique features such as the shape memory effect and pseudo-elasticity. Iron-based shape memory alloys (Fe-SMAs) have become popular in recent years. Use of iron-based SMAs for strengthening RC structures has received attention in the recent decade due to the advantages it presents, that is, no ducts or anchor heads are required, friction losses do not occur and no space is needed for a hydraulic device to exert force. Accordingly, Fe-SMAs embedded in a shotcrete layer have been used for pre-stressing RC beams at Empa. The aim of this study is to present an approach to model and analyze the behavior of RC members strengthened and pre-stressed with Fe-SMA rebars embedded in a shotcrete layer. The lack of research on developing finite element models for studying the behavior of concrete structures strengthened by iron-based shape memory alloys is addressed. Three-dimensional finite element models were developed in the commercial finite element code ABAQUS, using the concrete damaged plasticity model to predict the studied beams’ load–displacement response. The results of the finite element analyses show a considerably good agreement with the experimental data in terms of the beams’ cracking load and ultimate load capacity. The effects of different strengthening parameters, including SMA rebar diameter, steel rebar diameter and pre-stressing force level on the beam behavior, were investigated based on the verified finite element models. The results were compared. The load-displacement response of an 18-m concrete girder strengthened and pre-stressed with iron-based SMA bars was examined by the developed finite element model as a case study.
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Kamada, Y., J. N. Mohapatra, H. Kikuchi, S. Kobayashi, T. Murakami, and H. Watanabe. "Neutron Irradiation Effects on Mechanical and Magnetic Properties of Pre-deformed Iron-based Model Alloys." Journal of the Magnetics Society of Japan 37, no. 3-2 (2013): 147–50. http://dx.doi.org/10.3379/msjmag.1301r008.
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Fraś, E., K. Wiencek, M. Górny, and H. F. López. "Nodule count in ductile iron: theoretical model based on Weibull statistics." International Journal of Cast Metals Research 18, no. 3 (March 2005): 156–62. http://dx.doi.org/10.1179/136404605225023009.
Full textDissertations / Theses on the topic "Iron-based model alloys"
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Agrizzi, Ronqueti Larissa. "Study of grain boundary oxidation of high alloyed carbon steels at coiling temperature." Thesis, Compiègne, 2018. https://bibliotheque.utc.fr/Default/doc/SYRACUSE/2018COMP2405.
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Les aciers à haute résistance (AHSS) ont été largement utilisés dans le cadre d’applications automobiles visant à améliorer la sécurité et l’allègement des structures. Afin d'atteindre les objectifs en termes de propriétés mécaniques, ces nouveaux aciers sont composés de teneurs en éléments d’alliages beaucoup plus élevés (par exemple silicium et manganèse) que les aciers usuels. En conséquence, l'AHSS est susceptible de subir une oxydation interne sélective lors du refroidissement des bobines d’acier. L'oxydation sélective interne, en particulier l'oxydation aux joints de grains (GBO), est actuellement l'un des principaux obstacles à la production de ces aciers. Elle réduit le nombre de cycles avant la rupture de fatigue et rend ainsi difficile l’obtention des spécifications du client. Par conséquent, ce travail de thèse était axé sur l'effet de plusieurs paramètres sur le comportement à l’oxydation interne sélective. Parmi eux, l'impact de la décarburation, l'influence de la température de bobinage et de la couche de calamine, l'effet de différentes teneurs en silicium et / ou en manganèse et leur comportement en diffusion. De plus, l'impact de la désorientation des joints de grains sur l'oxydation interne a également été étudié. Des alliages modèles à base de fer binaires / ternaires ainsi que des aciers industriels ont été étudiés via un large ensemble de techniques expérimentales. Ces analyses ont mis en évidence une décarburation stable pour tous les échantillons étudiés qui n'a pas d'impact sur l'oxydation interne sélective pour une longue exposition aux conditions isothermes. Les profondeurs d’oxydation aux joints de grain ont été examinées selon les différentes configurations de tests et se sont révélées sensibles aux teneurs en silicium ou en manganèse. Pour certaines d'entre elles, différents comportements de diffusion du silicium ont été identifiés vis-à-vis de l'oxydation des joints de grains, en fonction des températures. Considérant quelques hypothèses restrictives, l'application de la théorie de l'oxydation interne sélective de Wagner a permis de déterminer le coefficient de diffusion de l'oxygène aux joints de grain. Pour surmonter certaines limites du modèle de Wagner, un modèle d'oxydation sélective a été appliqué pour comprendre l'effet de différents paramètres sur la pénétration de l'oxygène à l'intérieur du métal et principalement sur la profondeur des joints de grain affectée par l'oxydation sélective. Les connaissances acquises à partir de ce travail de thèse aideront à comprendre et à limiter l'oxydation sélective interne (principalement l’oxydation aux joints de grain) dans les aciers avec des compositions complexes en éléments d’alliage. En outre, les résultats peuvent être utilisés pour évaluer les paramètres d’un modèle d'oxydation sélectiveAdvanced high-strength steels (AHSS) have been widely used in automotive industry to improve safety and fuel economy. In order to reach the mechanical properties targets, these new steels are composed by much higher alloy contents (e.g. silicon and manganese) than usual steels. As consequence, the AHSS may suffer of selective internal oxidation during the cooling of hot coil. The selective internal oxidation, especially the grain boundary oxidation (GBO), is currently one of the main obstacles to the production of these steels. It reduces the number of cycles before fatigue failure and thus, makes it difficult to reach the specifications of the customer. Therefore, this PhD work was focused on the effect of several parameters on selective internal oxidation behavior. Among them, the impact of decarburization, the influence of coiling temperature and the mill scale, the effect of different silicon and/or manganese contents and their diffusion behavior. Moreover, the impact of grain boundary misorientation on grain boundary oxidation was also investigated. Either binary/ternary iron-based model alloys as well as industrial steels were investigated by a large set of experimental techniques. This analysis showed a stable decarburization for all investigated samples that does not impact the selective internal oxidation for long exposure time in isothermal conditions. The GBO depths were examined according to the different test configurations and were found dependent for some cases on silicon or manganese content. For some of them, different silicon diffusion behaviors were identified with regards to grain boundary oxidation depending on temperatures. Considering some restrictive hypotheses, the application of Wagner’s theory of selective internal oxidation allowed determining the grain boundary diffusion coefficient of oxygen. To overcome some limitations of Wagner’s model, a model of selective oxidation has been applied to understand the effect of different parameters on the penetration of oxygen inside the metal and principally on the grain boundary depth affected by selective oxidation. The knowledge acquired from this PhD work will help to understand and limit the selective internal oxidation (mainly GBO) in new steels with complex alloy compositions. Furthermore, the results may be used to assess a model of selective oxidation
Book chapters on the topic "Iron-based model alloys"
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Akopyan, Torgom, Nikolay Belov, and Evgenia Naumova. "Calcium-Containing Aluminum Alloys." In Encyclopedia of Aluminum and Its Alloys. Boca Raton: CRC Press, 2019. http://dx.doi.org/10.1201/9781351045636-140000264.
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The phase composition and microstructure of ternary alloys, Al–Ca–X (where X = (Silicon) Si, (Magnesium) Mg, (Zinc) Zn, (Copper) Cu, (Nickel) Ni, (Iron) Fe, (Manganese) Mn, and (Scandium) Sc), developed based on Ca-containing eutectics have been studied. In most systems, ternary compounds are detected. It is found that the structure of Ca-containing eutectics is much finer than that of Al–Si alloys. Such alloys have a good combination of technological properties during casting and deforming. Because of the high volume fraction of Ca-containing particles (up to 33 vol.%), they may be considered as promising “natural composites.” The strength properties of Al–Ca–X alloys may be significantly enhanced by adding Sc and Zr, forming L12 nanoparticles. Alloys of the system Al–Zn–Mg–Ca can reach hardnesses higher than 200 HB, which gives reason to expect good strength properties. With the example of the Al–9%Zn–3.5%Mg–3%Ca model experimental alloy based on the (Al) + (Al,Zn)4Ca eutectic, the possibility, in principle, of manufacturing rolled sheets has been demonstrated.
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Wang, Wei, Bo Wang, JiYuan Liu, and Hong Hai. "Constitutive model derivation and numerical simulation of iron based Shape Memory Alloy pipe joint." In Progress in Civil, Architectural and Hydraulic Engineering IV, 845–48. CRC Press, 2015. http://dx.doi.org/10.1201/b19383-173.
Full textConference papers on the topic "Iron-based model alloys"
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Atulasimha, Jayasimha, and Alison B. Flatau. "Energy-based model for the magnetostrictive behavior of polycrystalline iron-gallium alloys." In Smart Structures and Materials, edited by William D. Armstrong. SPIE, 2006. http://dx.doi.org/10.1117/12.658716.
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Lambrecht, Marlies, and Abderrahim Almazouzi. "Positron Defect Studies of Neutron Irradiated Iron-Based Materials." In 17th International Conference on Nuclear Engineering. ASMEDC, 2009. http://dx.doi.org/10.1115/icone17-75108.
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The hardening and embrittlement of reactor pressure vessel steels is of great concern in the actual nuclear power plant life assessment. The embrittlement is caused by irradiation-induced damage, like vacancies, interstitials, solutes and their clusters. But the reason for the embrittlement of the material is not yet totally known. The real nature of the irradiation damage should thus be examined as well as its evolution in time. Positron annihilation spectroscopy has been shown to be a very good method for analyzing these defects. Both vacancy type clusters and precipitates can be visualized by positrons. To be able to compare the results obtained by the positron studies, with those of other techniques (such as transmission electron microscopy, atom probe tomography and small angle neutron scattering), quantitative estimations of the size and density of the annihilation sites are needed. Using the approach proposed by A. Vehanen et al., an attempt is made to calculate the needed quantities in model alloys that were neutron irradiated to different doses. The results obtained will be discussed highlighting the difficulties in defining the annihilation centers in spite of using both lifetime and Doppler broadening measurements in the same samples, even in this simple model alloys.
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Cisse, Cheikh, Wael Zaki, and Tarak Ben Zineb. "A Model for Iron-Based Shape Memory Alloys Considering Variable Elastic Stiffness and Coupling Between Plasticity and Phase Transformation." In ASME 2015 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/smasis2015-8875.
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The paper presents a new constitutive model for iron-based shape memory alloys (Fe-SMAs) adapted from the ZM model initially proposed for Nitinol by Zaki and Moumni [JMPS2007]. The model introduces nonlinear hardening terms to account for interactions between the grains, martensite variants and slip systems that may exist within a volume element of the material. The expressions used for the hardening terms are similar to those in (Khalil et al. [JIMSS2012]). The equations of the model are derived from the expression of a Helmholtz free energy potential, with complementary loading conditions obtained within the framework of generalized standard materials with internal constraints. A detailed derivation of the implicit algorithm used for the integration of the model is provided and used for numerical simulations that are shown to agree with experimental data.
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Fang, Ning. "Sensitivity Analysis of the Material Flow Stress in Machining." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-41655.
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Among the effects of strain hardening, strain-rate hardening, and temperature softening, it has long been argued about which effect is predominant in governing the material flow stress in machining. This paper compares four material constitutive models commonly employed, including Johnson-Cook’s model, Oxley’s model, Zerilli-Armstrong’s model, and Maekawa et al.’s model. A new quantitative sensitivity analysis of the material flow stress is performed based on Johnson-Cook’s model covering a wide range of engineering materials, including plain carbon steels with different carbon contents, alloyed steels, aluminum alloys with different chemical compositions and heat treatment conditions, copper and copper alloys, iron, nickel, tungsten alloys, etc. It is demonstrated that the first predominant factor governing the material flow stress is either strain hardening or thermal softening, depending on the specific work material employed and the varying range of temperatures. Strain-rate hardening is the least important factor governing the material flow stress, especially when machining aluminum alloys.
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Tan, Honghao, and Mohammad H. Elahinia. "Modeling of Ferromagnetic Shape Memory Alloy Based Transducers for Electro-Hydraulic Actuators." In ASME 2005 International Mechanical Engineering Congress and Exposition. ASMEDC, 2005. http://dx.doi.org/10.1115/imece2005-80049.
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Ferromagnetic Shape Memory Alloys (FSMAs) like Ni-Mn-Ga have attracted significant attention over the past few years. What makes these materials attractive as actuators is their high energy density, large stroke, and high bandwidth. Among other applications, these properties make FSMAs potentially candidates for developing lightweight Electro-Hydraulic Actuators (EHA). The role of the FSMA transducer is to provide the mechanical energy by the linear displacement in the EHA. In order to develop effective FSMA-based transducers, it is important to study their dynamic behavior. In this paper a dynamic model is presented for a Ni-Mn-Ga transducer. The transducer consists of the Ni-Mn-Ga material, a linear spring, Helmholtz coils, and a soft iron housing. An enhanced phenomenological model is also presented in this work to describe the strain output of the actuator in the response to the magnetic field strength. Using this model the effect of design parameters on the performance of the actuator is studied.
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Lee, Dae Geon, Dae Soo Kim, Kyeong Jin Yang, Joon Ho Lee, and Seong Cheol Jang. "Environmental Fatigue Evaluation for Interface of Dissimilar Metal Welded Piping." In ASME 2017 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/pvp2017-65481.
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Environmental fatigue evaluation is a key technology to extend Nuclear Power Plant design life. Since USNRC issued the RG 1.207 in 2007, many studies on fatigue evaluation in Light water Reactor coolant environments have been carried out by referencing documents such as NUREG/CR-6909, EPRI-TR-1025823, ASME BPVC Sec. III NB-3600/3200 Code, ASME Code Case, and so on. These documents presented environmental fatigue evaluation methods about each single-metal such as carbon steels, low-alloy steels, nickel-chromium-iron (Ni-Cr-Fe) alloys, and austenitic stainless steels. However, the environmental fatigue evaluation method for interface of dissimilar metal welding is mostly insufficient. Dissimilar metal welding has been widely used in nuclear industry. If environmental fatigue analysis method for dissimilar metal welding is developed, it will facilitate the design of piping for more safety. Therefore, the development of environmental fatigue evaluation for the interface of dissimilar metal welding should be studied. This paper presents environmental fatigue evaluation for the interface of dissimilar metal welded piping. The environmental fatigue evaluation for a dissimilar metal welded piping model was performed based on above documents.
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Suckling, Paul, Nicola Calder, Paul Humphreys, Fraser King, and Helen Leung. "The Development and Use of T2GGM: A Gas Modelling Code for the Postclosure Safety Assessment of OPG’s Proposed L&ILW Deep Geologic Repository, Canada." In ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2009. http://dx.doi.org/10.1115/icem2009-16291.
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As part of the postclosure safety assessment of Ontario Power Generation’s (OPG’s) proposed Deep Geologic Repository (DGR) for Low and Intermediate Level Waste (L&ILW) at the Bruce site, Ontario, a Gas Generation Model (GGM) has been developed and used to model the detailed generation of gas within the DGR due to corrosion and microbial degradation of the organics and metals present. The GGM is based on a kinetic description of the various microbial and corrosion processes that lead to the generation and consumption of various gases. It takes into account the mass-balance equations for each of the species included in the model, including three forms of organic waste (cellulose, ionexchange resins, and plastics and rubbers), four metallic waste forms and container materials (carbon and galvanised steel, passivated carbon steel, stainless steel and nickel-based alloys, and zirconium alloys), six gases (CO2, N2, O2, H2, H2S, and CH4), five terminal electron acceptors (O2, NO3−, Fe(III), SO42−, and CO2), five forms of biomass (aerobes, denitrifiers, iron reducers, sulphate reducers, and methanogens), four types of corrosion product (FeOOH, FeCO3, Fe3O4, and FeS), and water. The code includes the possibility of the limitation of both microbial and corrosion reactions by the availability of water. The GGM has been coupled with TOUGH2 to produce T2GGM; a code that models the generation of gas in the repository and its subsequent transport through the geosphere. T2GGM estimates the peak repository pressure, long time repository saturation and the total flux of gases from the geosphere. The present paper describes the development of T2GGM and the numerical modelling work undertaken to calculate the generation and build-up of gas in the repository, the two-phase exchange of gas and groundwater between the repository and the surrounding rock, and between the rock and the surface environment. The results have been used to inform the safety assessment modelling.
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Schranz, Bernhard, Christoph Czaderski, Moslem Shahverdi, Julien Michels, Thomas Vogel, and Masoud Motavalli. "Ribbed iron-based shape memory alloy bars for pre-stressed strengthening applications." In IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management. Zurich, Switzerland: International Association for Bridge and Structural Engineering (IABSE), 2019. http://dx.doi.org/10.2749/guimaraes.2019.1394.
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<p>Iron-based shape memory alloys (Fe-SMA) are a cost-effective alternative to conventional strengthening materials. With their unique properties such as the shape-memory effect (SME), structures can be retrofitted regarding the serviceability state as well as ultimate load capacity. The term SME refers to the ability of the material to return to its original shape upon heating, after having been deformed at ambient temperature. The heating and cooling process are generally referred to as “activation” of the alloy. If the material is restrained at activation, the material is subjected to tensile stresses. This phenomenon can be used for structural pre-stressing. The Fe- SMA material can be produced in form of standard-geometry reinforcement bars, to be used for flexural as well as shear-strengthening of concrete members. As a base for novel strengthening methods, this study aims at investigating the thermo-mechanical behaviour of Fe-SMA bars under realistic conditions. It comprises loading the material after activation (pre-stressed), exposure to multi-cyclic loading and observation of relaxation behaviour of pre-stressed Fe-SMA bars. Experiments were performed with diameter 16 and 12 mm bars. The results show a highly non- linear stress-strain behaviour, unlike conventional pre-stressing materials. The experiments with activated samples show that the stress-strain curve of Fe-SMA bars loaded after activation will approach and then follow the curve of non-activated tensile tests approximately in the point of the initial deformation. Furthermore, analytical material models are developed which show good correspondence with experimental data and serve as a base for further studies and structural design.</p>
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Yoo, Jin-Hyeong, Alison Flatau, and Ashish Purekar. "Performance of Galfenol Energy Harvester at High Temperature." In ASME 2011 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. ASMEDC, 2011. http://dx.doi.org/10.1115/smasis2011-5040.
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Recently, the development of energy harvesting devices has received considerable interest as a means of powering nodes in a wireless sensor network. Additionally, the ability to operate in a high temperature environment is a desired feature especially in the case of wireless sensor networks used in a power plant where elevated temperatures are normal. Vibration based energy harvesting is one method of scavenging energy from the environment. Traditional approaches for vibration based energy harvesting have focused primarily on piezoelectric and electromagnetic approaches. There are, however, limitations associated with high temperature applications. Iron-Gallium alloys (Galfenol) are highly magnetostrictive with magnetically induced strains as high as 400 ppm in single crystals and 280 ppm in highly textured polycrystals. Galfenol is machineable, weldable, and has tensile strength of approximately 500 MPa. These unique properties foreshadow the material’s use in conventional transducers operating in severe environments. An investigation into the magnetostriction performance at temperatures up to 225°C found magnetostriction degraded relative to that at room temperature by close to 25%. From those measurements, two important advantages of Galfenol were found. First, even though the performance degraded at 225°C, the original performance is recovered when the temperature comes back to room temperature. The second advantage is that the performance at 225°C was stable. Based on these results, it was determined that Galfenol could be utilized at temperatures of at least 225 °C. In this paper, a series of tests are conducted in a thermal chamber to evaluate the Galfenol energy harvester performances from temperatures ranging from room temperature to 200°C. A linear coupled model for a Galfenol energy harvester is developed based on fundamental properties of a tuned mass beam system. A non-linear version of the model is developed and compared to experimental evaluations. A comparison with experimental evaluations provides good correlation with results. It is shown that the Galfenol energy harvester can provide consistent power from room temperature to 200°C.
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Zaki, Wael, Cheikh Cissé, and Tarak Ben Zineb. "Modeling and Simulation of Architectured Iron-Based SMA Materials." In ASME 2017 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/smasis2017-3759.
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The paper presents results of finite element analysis of architectured iron-based shape memory alloy (SMA) samples consisting of bulk SMA and void combined to different proportions and according to different geometric patterns. The finite element simulation uses a constitutive model for iron-based SMAs that was recently developed by the authors in order to account for the behavior of the bulk material. The simulation of the architectured SMA is then carried out using a unit cell method to simplify calculations and reduce computation time. For each unit cell, periodic boundary conditions are assumed and enforced. The validity of this assumption is demonstrated by comparing the average behavior of one unit cell to that of a considerably larger sample comprising multiple such cells. The averaging procedure used is implemented numerically, by calculating volume averages of mechanical fields such as stress and strain over each finite element model considered as a combination of mesh elements.
Reports on the topic "Iron-based model alloys"
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Choudhary, Ruplal, Victor Rodov, Punit Kohli, Elena Poverenov, John Haddock, and Moshe Shemesh. Antimicrobial functionalized nanoparticles for enhancing food safety and quality. United States Department of Agriculture, January 2013. http://dx.doi.org/10.32747/2013.7598156.bard.
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Original objectives The general goal of the project was to utilize the bactericidal potential of curcumin- functionalizednanostructures (CFN) for reinforcement of food safety by developing active antimicrobial food-contact surfaces. In order to reach the goal, the following secondary tasks were pursued: (a) further enhancement of the CFN activity based on understanding their mode of action; (b) preparing efficient antimicrobial surfaces, investigating and optimizing their performance; (c) testing the efficacy of the antimicrobial surfaces in real food trials. Background to the topic The project dealt with reducing microbial food spoilage and safety hazards. Cross-contamination through food-contact surfaces is one of the major safety concerns, aggravated by bacterial biofilm formation. The project implemented nanotech methods to develop novel antimicrobial food-contact materials based on natural compounds. Food-grade phenylpropanoidcurcumin was chosen as the most promising active principle for this research. Major conclusions, solutions, achievements In agreement with the original plan, the following research tasks were performed. Optimization of particles structure and composition. Three types of curcumin-functionalizednanostructures were developed and tested: liposome-type polydiacetylenenanovesicles, surface- stabilized nanoparticles and methyl-β-cyclodextrin inclusion complexes (MBCD). The three types had similar minimal inhibitory concentration but different mode of action. Nanovesicles and inclusion complexes were bactericidal while the nanoparticlesbacteriostatic. The difference might be due to different paths of curcumin penetration into bacterial cell. Enhancing the antimicrobial efficacy of CFN by photosensitization. Light exposure strengthened the bactericidal efficacy of curcumin-MBCD inclusion complexes approximately three-fold and enhanced the bacterial death on curcumin-coated plastic surfaces. Investigating the mode of action of CFN. Toxicoproteomic study revealed oxidative stress in curcumin-treated cells of E. coli. In the dark, this effect was alleviated by cellular adaptive responses. Under light, the enhanced ROS burst overrode the cellular adaptive mechanisms, disrupted the iron metabolism and synthesis of Fe-S clusters, eventually leading to cell death. Developing industrially-feasible methods of binding CFN to food-contact surfaces. CFN binding methods were developed for various substrates: covalent binding (binding nanovesicles to glass, plastic and metal), sonochemical impregnation (binding nanoparticles to plastics) and electrostatic layer-by-layer coating (binding inclusion complexes to glass and plastics). Investigating the performance of CFN-coated surfaces. Flexible and rigid plastic materials and glass coated with CFN demonstrated bactericidal activity towards Gram-negative (E. coli) and Gram-positive (Bac. cereus) bacteria. In addition, CFN-impregnated plastic material inhibited bacterial attachment and biofilm development. Testing the efficacy of CFN in food preservation trials. Efficient cold pasteurization of tender coconut water inoculated with E. coli and Listeriamonocytogeneswas performed by circulation through a column filled with CFN-coated glass beads. Combination of curcumin coating with blue light prevented bacterial cross contamination of fresh-cut melons through plastic surfaces contaminated with E. coli or Bac. licheniformis. Furthermore, coating of strawberries with CFN reduced fruit spoilage during simulated transportation extending the shelf life by 2-3 days. Implications, both scientific and agricultural BARD Report - Project4680 Page 2 of 17 Antimicrobial food-contact nanomaterials based on natural active principles will preserve food quality and ensure safety. Understanding mode of antimicrobial action of curcumin will allow enhancing its dark efficacy, e.g. by targeting the microbial cellular adaptation mechanisms.