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Articles de revues sur le sujet "Multiferroic Materials - Application Standpoint"
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Grotel, Jakub. « MAGNETOELECTRIC COUPLING MEASUREMENT TECHNIQUES IN MULTIFERROIC MATERIALS ». Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska 11, no 1 (31 mars 2021) : 10–14. http://dx.doi.org/10.35784/iapgos.2583.
Texte intégralRésumé :
Magnetoelectric multiferroics are solid-state materials which exhibit a coupling between ferroelectric and magnetic orders. This phenomenon is known as the magnetoelectric (ME) effect. Multiferroic materials possess a wide range of potential applications in such fields as metrology, electronics, energy harvesting & conversion, and medicine. Multiferroic research is facing two main challenges. Firstly, scientists are continuously trying to obtain a material with sufficiently strong, room-temperature ME coupling that would enable its commercial application. Secondly, the measurement techniques used in multiferroic research are often problematic to implement in a laboratory setting and fail to yield reproducible results. The aim of the present work is to discuss three most commonly used methods in multiferroic studies; the lock-in technique, the Sawyer-Tower (S-T) circuit and dielectric constant measurements. The paper opens with a general description of multiferroics which is followed by mathematical representation of the ME effect. The main body deals with the description of the aforementioned measurement techniques. The article closes with a conclusion and outlook for future research.
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Zhao, Shifeng. « Advances in Multiferroic Nanomaterials Assembled with Clusters ». Journal of Nanomaterials 2015 (2015) : 1–12. http://dx.doi.org/10.1155/2015/101528.
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As an entirely new perspective of multifunctional materials, multiferroics have attracted a great deal of attention. With the rapidly developing micro- and nano-electro-mechanical system (MEMS&NEMS), the new kinds of micro- and nanodevices and functionalities aroused extensive research activity in the area of multiferroics. As an ideal building block to assemble the nanostructure, cluster exhibits particular physical properties related to the cluster size at nanoscale, which is efficient in controlling the multiferroic properties for nanomaterials. This review focuses on our recent advances in multiferroic nanomaterials assembled with clusters. In particular, the single phase multiferroic films and compound heterostructured multiferroic films assembled with clusters were introduced detailedly. This technique presents a new and efficient method to produce the nanostructured multiferroic materials for their potential application in NEMS devices.
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Tablero, C. « Photovoltaic application of the multiferroic Bi 2 FeCrO 6 double perovskite ». Solar Energy 137 (novembre 2016) : 173–78. http://dx.doi.org/10.1016/j.solener.2016.08.004.
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Liang, Xianfeng, Cunzheng Dong, Huaihao Chen, Jiawei Wang, Yuyi Wei, Mohsen Zaeimbashi, Yifan He, Alexei Matyushov, Changxing Sun et Nianxiang Sun. « A Review of Thin-Film Magnetoelastic Materials for Magnetoelectric Applications ». Sensors 20, no 5 (10 mars 2020) : 1532. http://dx.doi.org/10.3390/s20051532.
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Since the revival of multiferroic laminates with giant magnetoelectric (ME) coefficients, a variety of multifunctional ME devices, such as sensor, inductor, filter, antenna etc. have been developed. Magnetoelastic materials, which couple the magnetization and strain together, have recently attracted ever-increasing attention due to their key roles in ME applications. This review starts with a brief introduction to the early research efforts in the field of multiferroic materials and moves to the recent work on magnetoelectric coupling and their applications based on both bulk and thin-film materials. This is followed by sections summarizing historical works and solving the challenges specific to the fabrication and characterization of magnetoelastic materials with large magnetostriction constants. After presenting the magnetostrictive thin films and their static and dynamic properties, we review micro-electromechanical systems (MEMS) and bulk devices utilizing ME effect. Finally, some open questions and future application directions where the community could head for magnetoelastic materials will be discussed.
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Gupta, Reema, Monika Tomar, Ashok Kumar et Vinay Gupta. « Performance of magnetoelectric PZT/Ni multiferroic system for energy harvesting application ». Smart Materials and Structures 26, no 3 (3 février 2017) : 035002. http://dx.doi.org/10.1088/1361-665x/26/3/035002.
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Wang, Jiawei, Aitian Chen, Peisen Li et Sen Zhang. « Magnetoelectric Memory Based on Ferromagnetic/Ferroelectric Multiferroic Heterostructure ». Materials 14, no 16 (17 août 2021) : 4623. http://dx.doi.org/10.3390/ma14164623.
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Electric-field control of magnetism is significant for the next generation of large-capacity and low-power data storage technology. In this regard, the renaissance of a multiferroic compound provides an elegant platform owing to the coexistence and coupling of ferroelectric (FE) and magnetic orders. However, the scarcity of single-phase multiferroics at room temperature spurs zealous research in pursuit of composite systems combining a ferromagnet with FE or piezoelectric materials. So far, electric-field control of magnetism has been achieved in the exchange-mediated, charge-mediated, and strain-mediated ferromagnetic (FM)/FE multiferroic heterostructures. Concerning the giant, nonvolatile, and reversible electric-field control of magnetism at room temperature, we first review the theoretical and representative experiments on the electric-field control of magnetism via strain coupling in the FM/FE multiferroic heterostructures, especially the CoFeB/PMN–PT [where PMN–PT denotes the (PbMn1/3Nb2/3O3)1−x-(PbTiO3)x] heterostructure. Then, the application in the prototype spintronic devices, i.e., spin valves and magnetic tunnel junctions, is introduced. The nonvolatile and reversible electric-field control of tunneling magnetoresistance without assistant magnetic field in the magnetic tunnel junction (MTJ)/FE architecture shows great promise for the future of data storage technology. We close by providing the main challenges of this and the different perspectives for straintronics and spintronics.
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Shah, Jyoti, K. C. Verma, Ashish Agarwal et R. K. Kotnala. « Novel application of multiferroic compound for green electricity generation fabricated as hydroelectric cell ». Materials Chemistry and Physics 239 (janvier 2020) : 122068. http://dx.doi.org/10.1016/j.matchemphys.2019.122068.
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Planes, Antoni, Teresa Castán et Avadh Saxena. « Thermodynamics of multicaloric effects in multiferroic materials : application to metamagnetic shape-memory alloys and ferrotoroidics ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 374, no 2074 (13 août 2016) : 20150304. http://dx.doi.org/10.1098/rsta.2015.0304.
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We develop a general thermodynamic framework to investigate multicaloric effects in multiferroic materials. This is applied to the study of both magnetostructural and magnetoelectric multiferroics. Landau models with appropriate interplay between the corresponding ferroic properties (order parameters) are proposed for metamagnetic shape-memory and ferrotoroidic materials, which, respectively, belong to the two classes of multiferroics. For each ferroic property, caloric effects are quantified by the isothermal entropy change induced by the application of the corresponding thermodynamically conjugated field. The multicaloric effect is obtained as a function of the two relevant applied fields in each class of multiferroics. It is further shown that multicaloric effects comprise the corresponding contributions from caloric effects associated with each ferroic property and the cross-contribution arising from the interplay between these ferroic properties. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.
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Makarova, Liudmila, Yuliya Alekhina, Elena Kramarenko, Alexander Omelyanchik, Valeria Rodionova, Olga Malyshkina et Nikolai Perov. « Composite multiferroic materials consisting of NdFeB and PZT particles embedded in elastic matrix : the appearance of electrical polarization in a constant magnetic field ». EPJ Web of Conferences 185 (2018) : 07008. http://dx.doi.org/10.1051/epjconf/201818507008.
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New composite materials consisting of polymer matrix with PZT and NdFeB microparticles were prepared and investigated in the work. It was found that magnetic properties such as saturation magnetization, coercivity, permeability, depend on mass concentration of the ferromagnetic particles in the samples. Also it was found that all samples had electrical polarization in DC external electric field. The electric properties such as coercivity, remanent polarization, the maximum polarization value, had changes in the external constant magnetic field 1.1 kOe. These changes depended on both concentrations of ferromagnetic and ferroelectric particles. This type of magnetoelectric transformation allows us to classify new materials as multiferroic materials. These new composite materials can easily be prepared of any shape, the final materials are flexible and resistant to external chemical influences. The area of application of new multiferroic materials varies from sensors to autonomous energy sources.
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Yeo, Hong Goo. « Review of Single-Phase Magnetoelectric Multiferroic Thin Film and Process ». Ceramist 24, no 3 (30 septembre 2021) : 295–313. http://dx.doi.org/10.31613/ceramist.2021.24.3.01.
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Advance in the growth and characterization of multiferroic thin film promises new device application such as next generation memory, nanoelectronics and energy harvesting. In this review, we provide a brief overview of recent progress in the growth, characterization and understanding of thin-film multiferroics. Driven by the development of thin film growth techniques, the ability to produce high quality multiferroic thin films offers researchers access to new phase and understanding of these materials. We discuss that epitaxial strain and atomic-level engineering of chemistry determine the muliferroic thin film properties. We then discuss the new structures and properties of non-equilibrium phases which is stabilized by strain engineering.
Thèses sur le sujet "Multiferroic Materials - Application Standpoint"
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Shang, Jing. « 2D Magnetic and multiferroic materials : Fundamental physics and application exploration from theoretical simulation ». Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/227367/1/Jing_Shang_Thesis.pdf.
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This thesis aims to propose the feasible approaches to control and manipulate the magnetism in two-dimensional (2D) magnets through magnetoelectric coupling by using density functional theory (DFT) calculations. It is found that the goal can be achieved by building 2D magnetic-ferroelectric heterostructures or seeking for the multiferroic candidates. The effective manipulations of magnetic states are expected to not only provide new insights into the fundamental research, but also pave the solid foundations for the spintronic applications.
Chapitres de livres sur le sujet "Multiferroic Materials - Application Standpoint"
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Liu, Jiahao, et Liang Fang. « Electric Field-Induced Magnetization Reversal of Multiferroic Nanomagnet ». Dans Magnetic Materials and Magnetic Levitation. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.91231.
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Using the inverse piezoelectric effect and inverse magnetostrictive effect in a multiferroic heterojunction, an electric field is able to control the magnetization switching of a uniaxial nanomagnet. Compared with traditional spintronic devices based on magnetic field, multiferroic nanomagnet devices have the advantages of ultra-low consumption and high radiation resistance, showing great application potential in modern high-integrated circuits and military electronic systems. However, the difficulties of electric field control of complete magnetization reversal of the nanomagnet and nanomagnet arrays in a nanomagnetic logic gate still restrict the developments of multiferroic nanomagnet device. In this chapter, the uniaxial nanomagnets in multiferroic heterojunctions are mainly discussed. The two core problems of the electric field control of nanomagnets and nanomagnetic logic gate are well solved.
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Zhu, Ruijian, Zengmei Wang, Zhenxiang Cheng et Hideo Kimura. « Ferroelectric nanofibers and their application in energy harvesting ». Dans Nanoscale Ferroelectric-Multiferroic Materials for Energy Harvesting Applications, 181–94. Elsevier, 2019. http://dx.doi.org/10.1016/b978-0-12-814499-2.00010-4.
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Chand Verma, Kuldeep, et Manpreet Singh. « Processing Techniques with Heating Conditions for Multiferroic Systems of BiFeO3, BaTiO3, PbTiO3, CaTiO3 Thin Films ». Dans Thermoelectricity [Working Title]. IntechOpen, 2021. http://dx.doi.org/10.5772/intechopen.101122.
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In this chapter, we have report a list of synthesis methods (including both synthesis steps & heating conditions) used for thin film fabrication of perovskite ABO3 (BiFeO3, BaTiO3, PbTiO3 and CaTiO3) based multiferroics (in both single-phase and composite materials). The processing of high quality multiferroic thin film have some features like epitaxial strain, physical phenomenon at atomic-level, interfacial coupling parameters to enhance device performance. Since these multiferroic thin films have ME properties such as electrical (dielectric, magnetoelectric coefficient & MC) and magnetic (ferromagnetic, magnetic susceptibility etc.) are heat sensitive, i.e. ME response at low as well as higher temperature might to enhance the device performance respect with long range ordering. The magnetoelectric coupling between ferromagnetism and ferroelectricity in multiferroic becomes suitable in the application of spintronics, memory and logic devices, and microelectronic memory or piezoelectric devices. In comparison with bulk multiferroic, the fabrication of multiferroic thin film with different structural geometries on substrate has reducible clamping effect. A brief procedure for multiferroic thin film fabrication in terms of their thermal conditions (temperature for film processing and annealing for crystallization) are described. Each synthesis methods have its own characteristic phenomenon in terms of film thickness, defects formation, crack free film, density, chip size, easier steps and availability etc. been described. A brief study towards phase structure and ME coupling for each multiferroic system of BiFeO3, BaTiO3, PbTiO3 and CaTiO3 is shown.
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Enoki, Toshiaki, Morinobu Endo et Masatsugu Suzuki. « Highly Conductive Graphite Fibers ». Dans Graphite Intercalation Compounds and Applications. Oxford University Press, 2003. http://dx.doi.org/10.1093/oso/9780195128277.003.0012.
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From the viewpoint of applications of GICs, a very interesting development is the enhancement in conductivity of the host graphite up to the range of metals, especially for pristine materials with fibrous forms. Much attention has been paid to the exploitation of the order of magnitude intercalation-induced enhancement of the electrical conductivity of graphite fibers for the fabrication of practical high-conductivity, lightweight conductors (Vogel et al., 1977; Goldberg and Kalnim, 1981; Manini et al., 1983, 1985; Murday et al., 1984; Meschi et al., 1986; Natarajan and Woollam, 1983; Natarajan et al., 1983a). The fiber geometry (large aspect length/diameter) ratio offers advantages relative to highly oriented pyrolytic graphite (HOPG) or bulk graphite for the measurement of several of the transport properties of GICs and for increasing the compositional stability of GICs both under ambient conditions and at elevated temperatures (Endo et al., 1981, 1983a). For bulk GICs, intercalation increases the density of carriers by the injection of electrons into the graphite planes in the case of donor guest species, and by injection of holes in the case of acceptor type (see Chapters 5 and 6). The intercalation-induced decrease in carrier mobility that results from the increased scattering by defects and the increased effective mass is outweighed by the larger increase in carrier density, resulting in a large conductivity enhancement as discussed in Section 6.1. The carriers are localized in the graphene planes, and for high-stage compounds (n ≥ 2) the carrier density falls off rapidly with distance from the graphite bounding layer owing to the screening of the charged intercalate layer by the surrounding graphite bounding layers. From an application standpoint, many of the applications of intercalated carbon fibers exploit the high specific conductivity of GICs, which can be expressed as a figure of merit in terms of the conductivity σ divided by the mass density ρm; for a good conductor like copper this is ~ 6 x 10−2 cm /gμΩ. For example, intercalated carbon fibers can provide a lightweight conductor for huge aircraft or motor vehicles, in which, respectively, about 1.5 tonne or 30 kg conventional metallic conductor is used.
Actes de conférences sur le sujet "Multiferroic Materials - Application Standpoint"
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Natesan, K. « Materials Performance in Advanced Combustion Systems ». Dans ASME 1993 International Gas Turbine and Aeroengine Congress and Exposition. American Society of Mechanical Engineers, 1993. http://dx.doi.org/10.1115/93-gt-201.
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A number of advanced technologies are being developed to convert coal into clean fuels for use as feedstock in chemical plants and for power generation. From the standpoint of component materials, the environments created by coal conversion and combustion in these technologies and their interactions with materials are of interest. The trend in the new or advanced systems is to improve thermal efficiency and reduce the environmental impact of the process effluents. This paper discusses several systems that are under development and identifies requirements for materials application in those systems. Available data on the performance of materials in several of the environments are used to examine the performance envelopes for materials for several of the systems and to identify needs for additional work in different areas.
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Nakahira, M., N. Takeda, K. Hada, E. Tada, K. Miya et Y. Asada. « Main Features of ITER Vacuum Vessel and Approach to Code Application ». Dans 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22675.
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The ITER Vacuum Vessel (VV) is a complex torus-shaped configuration with a double-walled structure and the main function is to provide a high degree of vacuum for DT operation and form an enclosure for containing radioactive materials. Such structural uniqueness requires quite different technologies and implementations from the existing plant, so that technical rules are to be evolved on design, fabrication and examination for assuring its structural reliability. A new code concept, namely system-based code for integrity, has been developed so as to optimize the total reliability to be attained for ITER operation, considering unique structural features and safety attractiveness. This paper describes structural features of the ITER VV from code standpoint and basic approach to code application, together with on-going research activities for supporting the code development.
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Saad, Pascinthe, Mamdouh M. Salama et Ove Jahnsen. « Application of Composites to Deepwater Top Tensioned Riser Systems ». Dans ASME 2002 21st International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/omae2002-28325.
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As offshore exploration and production activities head to deeper water, extensive efforts have been focused on mitigating the potential challenges associated with deep- and ultra deep-water riser systems. Such challenges include overcoming the hydrostatic stresses associated with the increased length of water column as well as the increase in overall riser system weight. The implementation of composites in offshore applications is perceived as a promising path forward with composite materials offering many advantages including high specific strength and stiffness, lighter weight, enhanced corrosion resistance, high thermal insulation, improved structural damping and favorable fatigue performance characteristics. This paper focuses on evaluating the potential of composite materials for applications to deepwater top tensioned riser systems from the standpoint of possible impact on overall system cost and reliability. Many deepwater development concepts utilize top tensioned production riser systems, mainly, for conveying production fluids from the wellhead to the surface processing facilities in a dry tree based field development solution. Top tensioned risers can be configured as dual or single barrier systems and can either be hydraulically or hydro-pneumatically supported as on a typical TLP system or pneumatically supported through positively buoyant air cans as on a Spar riser system. Many advantages can be derived from the use of composites on buoyancy can systems. Such advantages include a reduced system weight, higher net lift, smaller diameter cans, improved efficiency and a positive impact on required inspection frequency. Main advantages of using composites for an entire TLP riser system include a significant reduction in both tension requirement and tensioner weight resulting in substantial reduction in total deck loads. An overall assessment of the economic and structural impact of using composites as an alternative to steel will be presented for riser systems and riser system components of both deepwater development concepts.
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Al Masud, Md Abdulla, Zoubeida Ounaies et Paris von Lockette. « Multi-Field Processing of Micro-Platelets for Magneto-Active Applications ». Dans ASME 2018 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/smasis2018-8080.
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The orientation and spatial distribution of magnetic particles in smart mechano-magnetic composites are key to enhancing their actuation capability. In this study, we present a new experimental approach to tune the orientation and assembly of barium hexaferrite (BHF) micro-platelets in liquid polymers by applying uniform magnetic and alternating current (AC)-electric fields. First, we investigated the assembly of BHFs under different electric field amplitudes and frequencies in the silicone elastomer. After establishing the optimum parameters for electric and magnetic alignment, four different microstructures are fabricated namely (a) random (b) electrically aligned (c) magnetically aligned and (d) simultaneously electrically and magnetically aligned. Finally, microstructural and property characterizations are performed using OM, XRD, SEM, and VSM measurements. Our findings demonstrate that a variety of microstructures can be obtained depending on the nature of the applied external field: in the absence of any field, BHF platelets are organized as small stacks, owing to their intrinsic magnetic polarization. In contrast, application of an electric field creates chain-like structures where the orientation of the BHF stacks inside the chains is random. Application of a magnetic field enhances rotation of the BHF stacks, which are found to rotate inside the chain in directions dictated by the magnetic field. Finally, by applying simultaneous electric and magnetic fields while also tuning the processing parameters, BHF-composite film with a squareness ratio of 0.92 is obtained. In order to further extend the actuation capability of resulting composites, we will also experiment with electroactive polymer matrices such as P(VDF–TrFE–CTFE) terpolymer to fabricate a multiferroic material that can actuate under both electric and magnetic field.
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Goldberg, Benjamin, Nicholas Roberts, W. Gabe Powell et Elyse Burmester. « "Intelligent tutoring in the wild : leveraging mobile app technology to guide live training" ». Dans The 8th International Defence and Homeland Security Simulation Workshop. CAL-TEK srl, 2018. http://dx.doi.org/10.46354/i3m.2018.dhss.008.
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"Mobile computing technologies are extending how people can interact with educational and training content in a whole new way. Through high resolution displays, intuitive user interfacing, embedded sensing technologies, and well supported app development communities, there is a plethora of content that can be used to build effective materials that target knowledge and skill development. To truly enhance this new training paradigm, extending Intelligent Tutoring System (ITS) to support mobile interactions can provide a new means to managing training in a rich contextualized environment. In this instance, learning takes place in the natural environment where directed experiences focus on the elements surrounding one’s location. In this paper, we describe the development of a new mobile ITS application using the Generalized Intelligent Framework for Tutoring (GIFT; Sottilare, Goldberg, Brawner & Holden, 2012). The domain of land navigation was applied as a use case, with direct support for the United States Military Academy at West Point. We describe the training concept, how GIFT was extended to support this concept from an architectural and assessment standpoint, along with implementation plans for an initial training effectiveness study."
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Najafi, Hossein, Arkadi Zikin, Cameron Eibl, Franco Arosio et Thilo Krah-Tomala. « Novel Computationally Designed Brake Disc Coatings for Thermal Spray and Extra High-Speed Laser Cladding ». Dans EuroBrake 2021. FISITA, 2021. http://dx.doi.org/10.46720/9927565eb2021-mds-003.
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The automotive industry is faced with a significant impending regulatory and environmental challenge: dramatically and cost effectively reduce brake dust emissions. To meet this challenge at scale, a high performing wear and corrosion resistant solution is needed that combines the advantageous economics of cast iron with a cost effective and indualizable coating. Alternative technologies such as composite brake discs are untenable for mass production, due to high costs and poor mass market value. The solution is to leverage Oerlikon’s patented and big data driven Rapid Alloy Design (RAD) platform to engineer disruptive new materials specifically tailored for the application and intended deposition methods.</p><p><br></p><p>Oerlikon has recently developed two new materials using the RAD platform balancing the corrosion, wear, mechanical, substrate, manufacturing, cost, and environmental parameters demanded by the brake disc application. This development leveraged two promising and industrialized deposition methods, extra high-speed laser cladding (EHLA) and high velocity oxygen fuel (HVOF) thermal spray. From a performance standpoint, the materials combine high corrosion performance and high wear resistance in a crack free solution. The materials are manufactured using low cost conventional atomization techniques and deposited as a single layer coating, significantly reducing processing costs. Environmental constraints are incorporated into the material design by eliminating carcinogenic Cobalt, Nickel, and Copper.</p><p><br></p><p>This article communicates the latest results on the deposition and performance of the new materials on brake discs using EHLA and HVOF technologies.
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Kam, Pascal, Aaron Coppage, Calvin Kam, Sharin Shafian, Bong Steven Chun et Jinny Rhee. « Lead-Free, Fluxless Solder Joints to Synthetic Diamond ». Dans ASME 2008 International Mechanical Engineering Congress and Exposition. ASMEDC, 2008. http://dx.doi.org/10.1115/imece2008-67068.
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With the recent trends towards smaller heat sources and higher heat fluxes, conduction spreading resistance can become a bottleneck to efficient heat dissipation from temperature-sensitive components such as advanced microelectronics and high power light-emitting diodes (LEDs). However, the use of a high thermal conductivity heat spreader such as a synthetic chemically vapor deposited (CVD) diamond results in an additional interface between two materials. The near elimination of thermal interface resistance at material boundaries is critical for this application to be viable from a thermal standpoint. A lead-free, fluxless soldering process for joining metal substrates to a CVD diamond heat spreader was sought in this study to achieve the low thermal interface resistance and Restruction of Hazardous Substances Directive (RoHS) compliancy desired for this application. A typical titanium-platinum-gold metallization was applied to the surfaces of the diamond to enable it to bond with metal solders. Both indium solder and a popular tin-silver-copper solder (SAC305) were examined in this work. The indium was cold-welded to the substrates under pressure. The SAC305 solder was reflowed in a nitrogen furnace with variable pressure at the joint. The resulting solder thicknesses and joint quality were assessed using a scanning electron microscope (SEM). Lastly, a prototype of high-heat flux source with a CVD diamond spreader and forced convection with air was built to illustrate the thermal advantages of properly incorporating a diamond spreader with a fluxless solder bond.
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Kwon, Yong-Rak, et David M. Berchowitz. « Free-Piston Stirling Cooler for Electronics Cooling in High Temperature Environments ». Dans ASME 2007 InterPACK Conference collocated with the ASME/JSME 2007 Thermal Engineering Heat Transfer Summer Conference. ASMEDC, 2007. http://dx.doi.org/10.1115/ipack2007-33684.
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This paper discusses active cooling devices used to maintain acceptable temperature levels for electronics packages in a high temperature environment. The temperature control is provided by a free-piston Stirling cooler (FPSC). The FPSC is a compact, quiet, low-vibration, environmentally benign cooling device based on the Stirling cycle. In principle, the cold side temperature of the FPSC, that thermally regulates the electronics package, is controllable from a low end, at cryogenic temperatures, upwards to the hot side temperature, which is limited only to the maximum temperature survivable by the materials used to construct the driving motor. General characteristics of the FPSC are discussed from the standpoint of electronics cooling and various options for heat transport are presented. Two prototype FPSCs have been developed for cooling electronics packages in applications where it has not been possible to accomplish even close to the requirements with existing technology. The first prototype is being used to cool an electronics package to below 100°C in a 200°C operating environment. The hot side temperature of the FPSC was designed to operate at 230°C in order to reject heat to the 200°C ambient, while limiting the motor temperature to less than 250°C. A cooling capacity of 120 W was achieved. The second prototype is used to provide conditioned air for a sealed, waterproof, electronics enclosure that is exposed to a 60°C environment. The FPSC operating temperatures for this application are 30°C on the cold side and 80°C on the hot side, with a cooling capacity of 500 W.
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Langbein, Falko, Matthias Loidl, Alexander Eberhard et Robert Mergen. « Slide Bearing Types for Combustion Engines Designed for Upcoming Emission Regulations ». Dans ASME 2009 Internal Combustion Engine Division Fall Technical Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/icef2009-14054.
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Intelligent handling of our limited energy resources and the demand to reduce emissions are today the main drivers for developing efficient combustion engines. Therefore slide bearings and also other parts of the powertrain are facing major challenges caused by: Significantly increased operating pressure, temperature and sliding speed as well as the use of new lubricants and fuels. Furthermore, a ban of hazardous elements (e.g. lead, cadmium) in the applied materials is looming. With respect to above mentioned facts, the mechanical and tribological boundary conditions for bearings in future engines are subjected to change immensely. These changes can only be met by new lining materials and bearing types. From the standpoint of strength, the main critical factors are the soft phases — mainly tin and lead — added to both aluminum and copper based bearing alloys to obtain the necessary tribological behavior. Soft phases are limited in their temperature stability and in addition, lead is an environmental critical element and is restricted. For upcoming engine generations even novel aluminum-tin alloys will reach their performance limits and the classical leaded-bronze material as basis for tri-metal and sputter coatings can no longer cope with the life-time expectations. In addition, corrosion issues will come up due to new oil additives in truck and high speed engines. The present paper proposes, for the application in high speed and truck engines, new slide bearing types with appropriate characteristics and the desired performance required by engine designers: A high strength, thermally stable aluminum alloy with excellent mechanical properties by using re-crystallization inhibition mechanisms; a series of new solutions on the basis of a lead-free bronze linings having brilliant thermo-mechanical process capabilities resulting in high strength properties. Adequate tribological behavior is gained by combination of the new lining alloys with different surface layers. Fundamental working principles, development work and first application results of the new bearing types are presented in relation to existing solutions.
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Kandlikar, Satish G., et William J. Grande. « Evolution of Microchannel Flow Passages : Thermohydraulic Performance and Fabrication Technology ». Dans ASME 2002 International Mechanical Engineering Congress and Exposition. ASMEDC, 2002. http://dx.doi.org/10.1115/imece2002-32043.
Texte intégralRésumé :
This paper provides a roadmap of development in the thermal and fabrication aspects of microchannels as applied in the microelectronics and other high heat-flux cooling applications. Microchannels are defined as flow passages that have hydraulic diameters in the range of 10 to 200 micrometers. The impetus for microchannel research was provided by the pioneering work of Tuckerman and Pease [1] at Stanford University in the early eighties. Since that time, this technology has received considerable attention in microelectronics and other major application areas, such as fuel cell systems and advanced heat sink designs. After reviewing the advancement in heat transfer technology from a historical perspective, advantages of using microchannels in high heat flux cooling applications is discussed, and research done on various aspects of microchannel heat exchanger performance is reviewed. Single-phase performance for liquids is expected to be still describable by the conventional equations; however the gas flow may be influenced by the rarefaction effects. Two-phase flow is another topic that is still under active research. The evolution of research into microchannel heat sinks has paralleled the advancements made in microfabrication technology. The earliest microchannels were built using anisotropic wet chemical etching techniques based on alkali solutions. While this method has been exploited successfully, it does impose certain restrictions on silicon wafer type and geometry. Recently, anisotropic dry etching processes have been developed that circumvent these restrictions. In addition, dry etching methods can be significantly faster and, from a manufacturing standpoint, create fewer contamination and waste treatment problems. Advances in fabrication technology will continue to fuel improvements in microchannel heat sink performance and cost for the foreseeable future. Some fabrication areas that may spur advances include new materials, high aspect ratio patterning techniques other than dry etching, active fluid flow elements, and micromolding.
Rapports d'organisations sur le sujet "Multiferroic Materials - Application Standpoint"
1
Sansum, Andrew J. PR-248-9513-R01 Evaluation of Different Field Joint Coating Materials for Existing FBE Coated Pipe. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), novembre 1998. http://dx.doi.org/10.55274/r0012045.
Texte intégralRésumé :
The selection of girth weld coatings for pipe coated with fusion bonded epoxy is usually determined by specific criteria related to the particular project. Other than the actual long-term performance of the coating there are other factors that are generally considered such as field application criteria, production rates, and other economic considerations. It has been found that coatings applied to the girth weld areas of pipe are not performing to anticipated life expectancy. Some are failing in as little as five years resulting in corrosion of the steel under the joint coating material. The purpose of this project was to evaluate the selected coatings from a performance standpoint only to be compared with fusion-bonded epoxies in order to predict the life expectancy relative to the parent pipe coating. Laboratory testing using accelerated test conditions can give a good indication of the expected life of coating material.