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Articles 541 - 570 of 614
Full-Text Articles in Mechanical Engineering
A Novel Solid Oxide Redox Flow Battery For Grid Energy Storage, Nansheng Xu, Xue Li, Xuan Zhao, John B. Goodenough, Kevin Huang
A Novel Solid Oxide Redox Flow Battery For Grid Energy Storage, Nansheng Xu, Xue Li, Xuan Zhao, John B. Goodenough, Kevin Huang
Faculty Publications
In this work we report proof-of-concept of a novel redox flow battery consisting of a solid oxide electrochemical cell (SOEC) integrated with a redox-cycle unit. The charge/discharge characteristics were explicitly observed by operating between fuel cell and electrolysis modes of the SOEC along with “in-battery” generation and storage of H2 realized by an in situ closed-loop reversible steam-metal reaction in the redox-cycle unit. With Fe/FeO as the redox materials, the new storage battery can produce an energy capacity of 348 Wh/kg-Fe and round-trip efficiency of 91.5% over twenty stable charge/discharge cycles. This excellent performance combined with robustness, environmental friendliness …
Synthesis, Structural, Optical And Mechanical Characterization Of Srb2O4 Nanorods, Rui Li, Lihong Bao, Xiaodong Li
Synthesis, Structural, Optical And Mechanical Characterization Of Srb2O4 Nanorods, Rui Li, Lihong Bao, Xiaodong Li
Faculty Publications
Single crystalline strontium borate (SrB2O4) nanorods were synthesized for the first time via a facile sol–gel route at low temperature. The SrB2O4 nanorods have a good crystalline nature with the growth direction along the [511] orientation and they are transparent from the ultraviolet to the visible regimes. Nanoscale three-point bending tests were performed directly on individual nanorods to probe their mechanical properties using an atomic force microscope. The elastic modulus of SrB2O4 nanorods was measured to be 158.2 ± 2.8 GPa, exhibiting a significant increase compared with other borate nanostructures …
In Situ Synthesis Of Ultrafine Ss-Mno2/Polypyrrole Nanorod Composites For High-Performance Supercapacitors, Jianfeng Zang, Xiaodong Li
In Situ Synthesis Of Ultrafine Ss-Mno2/Polypyrrole Nanorod Composites For High-Performance Supercapacitors, Jianfeng Zang, Xiaodong Li
Faculty Publications
We report a remarkable observation that is at odds with the established notion that β-MnO2 was regarded as an undesirable candidate for supercapacitor applications. The specific capacitance of β-MnO2 can reach as high as 294 F g−1, which is comparable to the best crystallographic structure, like α-MnO2. The key is to substantially decrease the size of β-MnO2 powders to ultra small regime. We demonstrate a facile, simple, and effective approach to synthesizing ultrafine (<10 nm in diameter) β-MnO2/polypyrrole nanorod composite powders for high-performance supercapacitor electrodes. Our observation may encourage a revisit of the other good …
Characteristics Of The Hydrogen Electrode In High Temperature Steam Electrolysis Process, Chao Jin, Chenghao Yang, Fanglin Chen
Characteristics Of The Hydrogen Electrode In High Temperature Steam Electrolysis Process, Chao Jin, Chenghao Yang, Fanglin Chen
Faculty Publications
YSZ-electrolyte supported solid oxide electrolyzer cells (SOECs) using LSM-YSZ oxygen electrode but with three types of hydrogen electrode, Ni–SDC, Ni–YSZ and LSCM–YSZ have been fabricated and characterized under different steam contents in the feeding gas at 850°C. Electrochemical impedance spectra results show that cell resistances increase with the increase in steam concentrations under both open circuit voltage and electrolysis conditions, suggesting that electrolysis reaction becomes more difficult in high steam content. Pt reference electrode was applied to evaluate the contributions of the hydrogen electrode and oxygen electrode in the electrolysis process. Electrochemical impedance spectra and over potential of both electrodes …
A Generic Bamboo-Based Carbothermal Method For Preparing Carbide (Sic, B4C, Tic, Tac, Nbc, TiXNb1-XC, And TaX Nb1-XC) Nanowires, Xinyong Tao, Yiping Li, Jun Du, Yang Xia, Yingchao Yang, Hui Huang, Yongping Gan, Wenkui Zhang, Xiaodong Li
A Generic Bamboo-Based Carbothermal Method For Preparing Carbide (Sic, B4C, Tic, Tac, Nbc, TiXNb1-XC, And TaX Nb1-XC) Nanowires, Xinyong Tao, Yiping Li, Jun Du, Yang Xia, Yingchao Yang, Hui Huang, Yongping Gan, Wenkui Zhang, Xiaodong Li
Faculty Publications
Finding a general procedure to produce a whole class of materials in a similar way is a desired goal of materials chemistry. In this work, we report a new bamboo-based carbothermal method to prepare nanowires of covalent carbides (SiC and B4C) and interstitial carbides (TiC, TaC, NbC, TixNb1−xC, and TaxNb1−xC). The use of natural nanoporous bamboo as both the renewable carbon source and the template for the formation of catalyst particles greatly simplifies the synthesis process. Based on the structural, morphological and elemental analysis, volatileoxides or halides assisted …
Sr2Fe1.5Mo0.5O6 As Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells With La0.8Sr0.2Ga0.87Mg0.13O3 Electrolyte, Guoliang Xiao, Qiang Liu, Fei Zhao, Lei Zhang, Changrong Xia, Fanglin Chen
Sr2Fe1.5Mo0.5O6 As Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells With La0.8Sr0.2Ga0.87Mg0.13O3 Electrolyte, Guoliang Xiao, Qiang Liu, Fei Zhao, Lei Zhang, Changrong Xia, Fanglin Chen
Faculty Publications
The performance of Sr2Fe1.5Mo0.5O6 (SFMO) as a cathode material has been investigated in this study. The oxygen ionic conductivityof SFMO reaches 0.13 S cm-1 at 800°C in air. The chemical diffusion coefficient (Dchem) and surface exchange constant (kex) of SFMO at 750°C are 5.0 x 10-6 cm2 s-1 and 2.8 x 10-5 cm s-1, respectively, suggesting that SFMO may have good electrochemicalactivity for oxygen reduction. SFMO shows a thermal expansion coefficient (TEC) of 14.5 x 10-6 K-1 the …
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason R. Hattrick-Simpers, Wilbur S. Hurst, Sesha S. Srinivasan, James E. Maslar
Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason R. Hattrick-Simpers, Wilbur S. Hurst, Sesha S. Srinivasan, James E. Maslar
Faculty Publications
An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storagematerials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element …
High Conductivity Solid Oxide Electrolyte Composite-Laminates Utilizing Scandia/Ceria Co-Doped Zirconia Core With Yttria Stabilized Zirconia Outer Skins, Jay Neutzler, Xinyu Huang, Joshua Sightler, Yan Chen, Nina Orlovskaya
High Conductivity Solid Oxide Electrolyte Composite-Laminates Utilizing Scandia/Ceria Co-Doped Zirconia Core With Yttria Stabilized Zirconia Outer Skins, Jay Neutzler, Xinyu Huang, Joshua Sightler, Yan Chen, Nina Orlovskaya
Faculty Publications
Increasing the conductivity of electrolytes in lower temperature Solid Oxide Fuel Cells (SOFC) is of great importance. However, there are several challenges that are to be addressed, which include phase stability of electrolyte’s crystal structure, chemical stability in both oxidizing and reducing environments, and maintaining mechanical integrity and high ionic conductivity over time.
Mechanical Characterization Of Polymer Electrolyte Membrane With Optical Methods, Xinyu Huang, Luis Alva, Jay Neutzler
Mechanical Characterization Of Polymer Electrolyte Membrane With Optical Methods, Xinyu Huang, Luis Alva, Jay Neutzler
Faculty Publications
Mechanical properties of polymer electrolyte membrane have important implications in the endurance of many electrochemical energy conversion devices [1]. Mechanical experiments are effective method to reveal discrete damage developed in the membrane by quantifying the change of mechanical strength and toughness. Regular strain measurement methods are overly intrusive to the thin and relatively fragile polymer electrolyte membrane; hence optical-based minimal invasive stress/strain measurement methods are studied.
Effective Ionic Conductivity Of A Novel Intermediate-Temperature Mixed Oxide-Ion And Carbonate-Ion Conductor, Xue Li, Guoliang Xiao, Kevin Huang
Effective Ionic Conductivity Of A Novel Intermediate-Temperature Mixed Oxide-Ion And Carbonate-Ion Conductor, Xue Li, Guoliang Xiao, Kevin Huang
Faculty Publications
A systematic investigation on the effective ionic conductivity (σm) of a novel intermediate-temperature mixed oxide-ion and carbonate-ion conductor MOCC consisting of a ceria phase and a carbonate phase is reported. The study explicitly shows that the observed remarkable temperature-dependent σm is primarily the result of softening/melting of the carbonate phase as the physical state of the carbonate phase transforms from solid, softened to molten. Differential scanning calorimetry analysis complements the understanding of the observed electrical behavior by revealing temperatures of melting and solidification in agreement with the onset temperatures of σm. In addition, the …
Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue
Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue
Faculty Publications
Porous electrode is the critical component of solid-oxide fuel cells (SOFCs) and provides a functional material backbone for multi-physicochemical processes. Model based electrode designs could significantly improve SOFC performance. This task is usually performed via parameter studies for simple case and assumed property distributions for graded electrodes. When nonlinearly coupled multiparameters of electrodes are considered, it could be very difficult for the model based parameter study method to effectively and systematically search the design space. In this research, the optimization approach with a genetic algorithm is demonstrated for this purpose. An anode-supported proton conducting SOFC integrated with a fuel supply …
Geometry-Dependent Oxygen Diffusion Flux And Limiting Current Density Of The Cathode In A Cathode-Supported Solid Oxide Fuel Cell, Kevin Huang, James L. Shull
Geometry-Dependent Oxygen Diffusion Flux And Limiting Current Density Of The Cathode In A Cathode-Supported Solid Oxide Fuel Cell, Kevin Huang, James L. Shull
Faculty Publications
An analysis is performed on the diffusion of oxygen through tubular porous cathode substrates having several different geometries. It is shown that the flux of oxygen as it diffuses through these different substrate geometries can be explicitly expressed by a general analytical form with a unique geometric factor for each type of substrate geometry. Experimental measurements of the geometry-independent term, oxygen diffusivity, were conducted for two representative geometries: cylindrical and triangular tubes. These measurements show good agreement between samples with similar porosities and thus favorably support the oxygen flux equations presented. Formulations for the limiting current density were also derived …
Cathode Polarizations Of A Cathode-Supported Solid Oxide Fuel Cell, Kevin Huang, Alessandro Zampieri, Martin Ise
Cathode Polarizations Of A Cathode-Supported Solid Oxide Fuel Cell, Kevin Huang, Alessandro Zampieri, Martin Ise
Faculty Publications
The concentration, activation, and total polarizations of the cathode in a cathode-supported solid oxide fuel cell (SOFC) were theoretically and experimentally investigated. In the theoretical analysis, the exchange current density of the charge transfer was considered to be dependent on the PO2 determined by the preceding O2 diffusion, resulting in an interrelationship between activation and concentration polarizations. The established nonlinear polarization equations were then applied to solve the key parameters with area specific resistances and overpotentials of the polarizations experimentally measured by electrochemical impedance spectroscopy on an operating cathode-supported SOFC. To ensure the consistency and meaningfulness of …
Adhesion At Diamond /Metal Interfaces: A Density Functional Theory Study, Haibo Guo, Yue Qi, Xiaodong Li
Adhesion At Diamond /Metal Interfaces: A Density Functional Theory Study, Haibo Guo, Yue Qi, Xiaodong Li
Faculty Publications
To understand the basic material properties required in selecting a metallic interlayer for enhanced adhesion of diamondcoatings on the substrates, the interfaces between diamond and metals with different carbide formation enthalpies (Cu, Ti, and Al) are studied using density functional theory. It is found that the work of separation decreases, while the interface energy increases, with the carbide formation enthalpy ΔHf (Tiys (Ti>Cu>Al), is needed to achieve a higher overall interface strength. In addition, when the surface energy is larger than the interface energy, a wetted diamond/metal interface is formed during diamondnucleation, providing the strongest adhesion …
A Novel Far-Field Nanoscopic Velocimetry For Nanofluidics, C. Kuang, Guiren Wang
A Novel Far-Field Nanoscopic Velocimetry For Nanofluidics, C. Kuang, Guiren Wang
Faculty Publications
For the first time we have been able to measure the flow velocity profile for nanofluidics with a spatial resolution better than 70 nm. Due to the diffraction resolution barrier, traditional optical methods have so far failed in measuring the velocity profile in a nanocapillary or a closed nanochannel without an opened sidewall. A novel optical point measurement method is presented which applies stimulated emission depletion (STED) microscopy to laser induced fluorescence photobleaching anemometer (LIFPA) techniques to measure flow velocity. Herein we demonstrate this far-field nanoscopic velocimetry method by measuring the velocity profile in a nanocapillary with an inner diameter …
Structural Health Monitoring With Piezoelectric Wafer Active Sensors—Predictive Modeling And Simulation, Victor Giurgiutiu
Structural Health Monitoring With Piezoelectric Wafer Active Sensors—Predictive Modeling And Simulation, Victor Giurgiutiu
Faculty Publications
This paper starts a review of the state of the art in structural health monitoring with piezoelectric wafer active sensors and follows with highlighting the limitations of the current approaches which are predominantly experimental. Subsequently, the paper examines the needs for developing a predictive modeling methodology that would allow to perform extensive parameter studies to determine the sensing method’s sensitivity to damage and insensitivity to confounding factors such as environmental changes, vibrations, and structural manufacturing variability. The thesis is made that such a predictive methodology should be multi-scale and multi-domain, thus encompassing the modeling of structure, sensors, electronics, and power …
Structural Health Monitoring With Piezoelectric Wafer Active Sensors--Predictive Modeling And Simulation, Victor Giurgiutiu
Structural Health Monitoring With Piezoelectric Wafer Active Sensors--Predictive Modeling And Simulation, Victor Giurgiutiu
Faculty Publications
This paper starts a review of the state of the art in structural health monitoring with piezoelectric wafer active sensors and follows with highlighting the limitations of the current approaches which are predominantly experimental. Subsequently, the paper examines the needs for developing a predictive modeling methodology that would allow to perform extensive parameter studies to determine the sensing method’s sensitivity to damage and insensitivity to confounding factors such as environmental changes, vibrations, and structural manufacturing variability. The thesis is made that such a predictive methodology should be multi-scale and multi-domain, thus encompassing the modeling of structure, sensors, electronics, and power …
Enhance Diamond Coating Adhesion By Oriented Interlayer Microcracking, Habio Guo, Xingcheng Xiao, Yue Qi, Zhi-Hui Xu, Xiaodong Li
Enhance Diamond Coating Adhesion By Oriented Interlayer Microcracking, Habio Guo, Xingcheng Xiao, Yue Qi, Zhi-Hui Xu, Xiaodong Li
Faculty Publications
In this paper, we report a microcrack toughening mechanism for enhancing the adhesion of diamondcoating. The oriented microcracks were formed within the TiC interlayer to dissipate strain energy and accommodate deformation via the crack opening-closing mechanism, thus enhancing the coating/substrate interfacial toughness. The delamination of diamondcoating was effectively prevented when the parallel microcracks were confined within the interlayer and arrested at interfaces of coating/interlayer/substrate. Density functional theory calculations revealed that the highly anisotropicfracture strength of the TiC phase energetically favors crack initiation and propagation along (100) planes only, which are 54.7° away from the interface. These microcracks are constrained inside …
Tobacco Mosaic Virus Templated Synthesis Of One Dimensional Inorganic-Polymer Hybrid Fibres, Jianhua Rong, Fiona Oberbeck, Xinnan Wang, Xiaodong Li, Jerry Oxsher, Zhongwei Niu, Qian Wang
Tobacco Mosaic Virus Templated Synthesis Of One Dimensional Inorganic-Polymer Hybrid Fibres, Jianhua Rong, Fiona Oberbeck, Xinnan Wang, Xiaodong Li, Jerry Oxsher, Zhongwei Niu, Qian Wang
Faculty Publications
Inorganic–polymer hybrid nanofibres were prepared by using a rod-like tobacco mosaic virus (TMV) as a template. With tetraethylorthosilicate (TEOS) as a precursor, long silica-coated TMVfibres were formed via a head-to-tail assembly, which showed a substantial increase of the elastic modulus. Furthermore, homogenous titania–TMV hybrid fibres could be prepared using polyaniline-coated TMV fibres as a template, which were used to form a composite film that was able to sense liquefied petroleum gases.
La0.85Sr0.15Mno3− Infiltrated Y0.5Bi1.5O3 Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells, Jiang Zhiyi, Changrong Xia, Fei Zhao, Fanglin Chen
La0.85Sr0.15Mno3− Infiltrated Y0.5Bi1.5O3 Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells, Jiang Zhiyi, Changrong Xia, Fei Zhao, Fanglin Chen
Faculty Publications
Porous yttria-stabilized bismuth oxides (YSB) were investigated as the backbones for (LSM) infiltrated cathodes in intermediate-temperature solid oxide fuel cells. The cathodes were evaluated using anode-supported single cells with scandia-stabilized zirconia as the electrolytes. With humidified as the fuel, the cell showed peak power density of 0.33, 0.52, and at 650, 700, and , respectively. At , the cell polarization resistance was only , of the lowest value previously reported, indicating that YSB is a promising backbone for the LSM infiltrated cathode.
Low Temperature, Organic-Free Synthesis Of Ba3B6O9(Oh)6 Nanorods And Ss-Bab2O4 Nanospindles, Rui Li, Xinyoung Tao, Xiaodong Li
Low Temperature, Organic-Free Synthesis Of Ba3B6O9(Oh)6 Nanorods And Ss-Bab2O4 Nanospindles, Rui Li, Xinyoung Tao, Xiaodong Li
Faculty Publications
Using a low temperature, organic-free hydrothermal technique, single-crystalline barium polyborate Ba3B6O9(OH)6 (BBOH) nanorods were synthesized. It was found that β-BaB2O4(BBO) nanospindles can be achieved by annealing the BBOH nanorods at a relatively low temperature of 810 °C. Transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques were used to characterize these nanomaterials. The formation mechanisms are discussed in conjunction with the crystallographic characteristics and surface energy of the BBOH nanorods and BBO nanospindles. UV-vis absorption spectra demonstrated that both BBOH nanorods and BBO nanospindles are …
Unveiling The Formation Mechanism Of Pseudo-Single-Crystal Aragonite Platelets In Nacre, Xiaodong Li, Zaiwang Huang
Unveiling The Formation Mechanism Of Pseudo-Single-Crystal Aragonite Platelets In Nacre, Xiaodong Li, Zaiwang Huang
Faculty Publications
We demonstrate direct evidence that a single-crystal-like aragonite platelet is essentially assembled with aragonite nanoparticles. The aragonite nanoparticles are readily oriented and assembled into pseudo-single-crystal aragonite platelets via screw dislocation and amorphous aggregation, which are two dominant mediating mechanisms between nanoparticles during biomineralization. These findings will advance our understanding of nacre’s biomineralization process and provide additional design guidelines for developing biomimetic materials.
Inhomogeneous Degradation Of Polymer Electrolyte Membrane In Pem Fuel Cells, Xinyu Huang, Wonseok Yoon
Inhomogeneous Degradation Of Polymer Electrolyte Membrane In Pem Fuel Cells, Xinyu Huang, Wonseok Yoon
Faculty Publications
Membrane durability is one of the technical barriers for the commercialization of polymer electrolyte membrane (PEM) fuel cells. Membrane embrittlement (a form of mechanical weakening) can lead to the frequently observed “sudden death” behavior of PEM fuel cells. It is the objective of this study to explore the fundamental mechanisms of the mechanical weakening of perfluorosulfonic acid (PFSA) based electrolyte membranes during the accelerated degradation test.
Predicting Young’S Modulus Of Nanowires From First-Principles Calculations On Their Surface And Bulk Materials, Guofeng Wang, Xiaodong Li
Predicting Young’S Modulus Of Nanowires From First-Principles Calculations On Their Surface And Bulk Materials, Guofeng Wang, Xiaodong Li
Faculty Publications
Using the concept of surface stress, we developed a model that is able to predict Young’s modulus of nanowires as a function of nanowire diameters from the calculated properties of their surface and bulk materials. We took both equilibrium strain effect and surface stress effect into consideration to account for the geometric size influence on the elastic properties of nanowires. In this work, we combined first-principles density functional theory calculations of material properties with linear elasticity theory of clamped-end three-point bending. Furthermore, we applied this computational approach to Ag, Au, and ZnOnanowires. For both Ag and Aunanowires, our theoretical predictions …
Predicting The Hydrogen Pressure To Achieve Ultralow Friction And Diamondlike Carbon Surfaces From First Principles, Haibo Guo, Yue Qi, Xiaodong Li
Predicting The Hydrogen Pressure To Achieve Ultralow Friction And Diamondlike Carbon Surfaces From First Principles, Haibo Guo, Yue Qi, Xiaodong Li
Faculty Publications
Hydrogen atmosphere can significantly change the tribological behavior at diamond and diamondlike carbon (DLC) surfaces and the friction-reducing effect depends on the partial pressure of hydrogen. We combined density functional theory modeling and thermodynamic quantities to predict the equilibrium partial pressures of hydrogen at temperature T, PH2 (T), for a fully atomic hydrogen passivated diamondsurface. Above the equilibrium PH2 (T), ultralow friction can be achieved at diamond and DLC surfaces. The calculation agrees well with friction tests at various testing conditions. We also show that PH2 (T) …
Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu
Elastic Wave Field Computation In Multilayered Nonplanar Solid Structures: A Mesh-Free Semianalytical Approach, Sourav Banerjee, Tribikram Kundu
Faculty Publications
Multilayered solid structures made of isotropic, transversely isotropic, or general anisotropic materials are frequently used in aerospace, mechanical, and civil structures. Ultrasonic fields developed in such structures by finite size transducers simulating actual experiments in laboratories or in the field have not been rigorously studied. Several attempts to compute the ultrasonic field inside solid media have been made based on approximate paraxial methods like the classical ray tracing and multi-Gaussian beam models. These approximate methods have several limitations. A new semianalytical method is adopted in this article to model elastic wave field in multilayered solid structures with planar or nonplanar …
). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li
). Size Dependency Of The Elastic Modulus Of Zno Nanowires: Surface Stress Effect, Guofeng Wang, Xiaodong Li
Faculty Publications
Relation between the elastic modulus and the diameter (D) of ZnOnanowires was elucidated using a model with the calculated ZnOsurface stresses as input. We predict for ZnOnanowires due to surface stress effect: (1) when D>20nm, the elastic modulus would be lower than the bulk modulus and decrease with the decreasing diameter, (2) when 20nm>D>2nm, the nanowires with a longer length and a wurtzite crystal structure could be mechanically unstable, and (3) when D<2nm, the elastic modulus would be higher than that of the bulk value and increase with a decrease in nanowire diameter.
Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li
Nanoindentation Of The A And C Domains In A Tetragonal Batio3 Single Crystal, Young-Bae Park, Matthew J. Dicken, Zhi-Hui Xu, Xiaodong Li
Faculty Publications
Nanoindentation in conjunction with piezoresponse force microscopy was used to study domain switching and to measure the mechanical properties of individual ferroelectric domains in a tetragonal BaTiO3 single crystal. It was found that nanoindentation has induced local domain switching; the a and c domains of BaTiO3 have different elastic moduli but similar hardness.Nanoindentationmodulus mapping on the a and c domains further confirmed such difference in elasticity. Finite element modeling was used to simulate the von Mises stress and plastic strain profiles of the indentations on both a and c domains, which introduces a much higher stress level than …
Iii Finishing, Lapping, Honing And Polishing: Processes, Characterisation And Novel Techniques-Experimental Research On Ultra-Smooth Surface Polishing Based On Two-Dimensional Vibration Of Liquid, Zhong Ning Guo, X. Z. Huang, Z. G. Huang, Z. Q. Yu, T. M. Yue, Wing Bun Lee
Iii Finishing, Lapping, Honing And Polishing: Processes, Characterisation And Novel Techniques-Experimental Research On Ultra-Smooth Surface Polishing Based On Two-Dimensional Vibration Of Liquid, Zhong Ning Guo, X. Z. Huang, Z. G. Huang, Z. Q. Yu, T. M. Yue, Wing Bun Lee
Faculty Publications
No abstract provided.
Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang
Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang
Faculty Publications
Proton exchange membrane fuel cell based power systems are on the verge of commercialization for a number of niche applications where batteries are traditionally used. Uninterrupted power supply (UPS) for wireless communication towers and broadband network relay utilities is one of the targeted application of fuel cell power systems with capacity ranging from one to serveral kilowatts. It is believed that fuel cell based UPS systems can offer considerable advantage when extended backup time is desirable. In order to replace the well-known battery based UPS systems, the reliability and perofrmance of fuel cell based UPS system need to be thoroughly …