Applied Mechanics Commons^™

Sr2Fe1.5Mo0.5O6-Δ – Sm0.2Ce0.8O1.9 Composite Anodes For Intermediate-Temperature Solid Oxide Fuel Cells, Beibei He, Ling Zhao, Shuxiang Song, Tong Liu, Fanglin Chen, Changrong Xia

Faculty Publications

Sr₂Fe_1.5Mo_0.5O_6−δ (SFM) perovskite is carefully investigated as an anode material for solid oxide fuel cells with LaGaO₃-based electrolytes. Its electronic conductivity under anodic atmosphere is measured with four-probe method while its ionic conductivity is determined with oxygen permeation measurement. Samaria doped ceria (SDC) is incorporated into SFM electrode to improve the anodic performance. A strong relation is observed between SDC addition and polarization losses, suggesting that the internal SFM-SDC contacts are active for H₂ oxidation. The best electrode performance is achieved for the composite with 30 wt% SDC addition, resulting …

3d Simulation Of Wind Turbine Rotors At Full Scale. Part Ii: Fluid–Structure Interaction Modeling With Composite Blades, Y. Bazilevs, Ming-Chen Hsu, J. Kiendel, R. Wuchner, K. U. Bletzigner

Ming-Chen Hsu

In this two-part paper, we present a collection of numerical methods combined into a single framework, which has the potential for a successful application to wind turbine rotor modeling and simulation. In Part 1 of this paper we focus on: 1. The basics of geometry modeling and analysis-suitable geometry construction for wind turbine rotors; 2. The fluid mechanics formulation and its suitability and accuracy for rotating turbulent flows; 3. The coupling of air flow and a rotating rigid body. In Part 2, we focus on the structural discretization for wind turbine blades and the details of the fluid–structure interaction computational …

High-Performance Computing Of Wind Turbine Aerodynamics Using Isogeometric Analysis, Ming-Chen Hsu, Ido Akkerman, Yuri Bazilevs

Ming-Chen Hsu

In this article we present a high-performance computing framework for advanced flow simulation and its application to wind energy based on the residual-based variational multiscale (RBVMS) method and isogeometric analysis. The RBVMS formulation and its suitability and accuracy for turbulent flow in a moving domain are presented. Particular emphasis is placed on the parallel implementation of the methodology and its scalability. Two challenging flow cases were considered: the turbulent Taylor–Couette flow and the NREL 5 MW offshore baseline wind turbine rotor at full scale. In both cases, flow quantities of interest from the simulation results compare favorably with the reference …

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

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

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, Ti_xNb_1−xC, and Ta_xNb_1−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 …

3d Simulation Of Wind Turbine Rotors At Full Scale. Part I: Geometry Modeling And Aerodynamics, Y. Bazilevs, Ming-Chen Hsu, I. Akkerman, S. Wright, K. Takizawa, B. Henicke, T. Spielman, T. E. Tezduyar

Ming-Chen Hsu

In this two-part paper we present a collection of numerical methods combined into a single framework, which has the potential for a successful application to wind turbine rotor modeling and simulation. In Part 1 of this paper we focus on: 1. The basics of geometry modeling and analysis-suitable geometry construction for wind turbine rotors; 2. The fluid mechanics formulation and its suitability and accuracy for rotating turbulent flows; 3. The coupling of air flow and a rotating rigid body. In Part 2 we focus on the structural discretization for wind turbine blades and the details of the fluid–structure interaction computational …

Reverse Logic - Safety Of Spent Nuclear Fuel Disposal, Antti Lempinen, Marianne Silvan-Lempinen

Antti Lempinen

No abstract provided.

The Bending Strip Method For Isogeometric Analysis Of Kirchhoff–Love Shell Structures Comprised Of Multiple Patches, J. Kiendel, Y. Bazilevs, Ming-Chen Hsu, R. Wuchner, K. U. Bletzigner

Ming-Chen Hsu

In this paper we present an isogeometric formulation for rotation-free thin shell analysis of structures comprised of multiple patches. The structural patches are C1- or higher-order continuous in the interior, and are joined with C0-continuity. The Kirchhoff–Love shell theory that relies on higher-order continuity of the basis functions is employed in the patch interior as presented in Kiendl et al. [36]. For the treatment of patch boundaries, a method is developed in which strips of fictitious material with unidirectional bending stiffness and zero membrane stiffness are added at patch interfaces. The direction of bending stiffness is chosen to be transverse …

Isogeometric Shell Analysis: The Reissner–Mindlin Shell, D. J. Benson, Y. Bazilevs, Ming-Chen Hsu, T.J.R. Hughes

Ming-Chen Hsu

A Reissner–Mindlin shell formulation based on a degenerated solid is implemented for NURBS-based isogeometric analysis. The performance of the approach is examined on a set of linear elastic and nonlinear elasto-plastic benchmark examples. The analyses were performed with LS-DYNA, an industrial, general-purpose finite element code, for which a user-defined shell element capability was implemented. This new feature, to be reported on in subsequent work, allows for the use of NURBS and other non-standard discretizations in a sophisticated nonlinear analysis framework.

Design And Development Of Rapid Battery Exchange Systems For Electric Vehicles To Be Used As Efficient Student Transportation, Jonathan A. Bevier

Master's Theses

Rapid battery exchange systems were built for an electric van and pedal assist electric bike as a method of eliminating the need to recharge the vehicles batteries in order to increase the feasibility of using electric propulsion as a method of efficient student transportation. After selecting proper materials it was found that the systems would need a protective coating to ensure consistent operation. 1020 cold rolled steel samples coated with multiple thicknesses of vinyl resin paint, epoxy resin paint, and powder coating were subjected to environmental wear tests in order to determine if the type and thickness of common protective …

An On-Sun Parametric Study Of Solar Hydrogen Production Using Wo3 Photoanodes, Christopher K. Halford

UNLV Theses, Dissertations, Professional Papers, and Capstones

The solar production of hydrogen using photoactive electrodes is a topic receiving much attention in recent years. The use of thin metal oxide films as photoanodes allows the water splitting reaction to occur at a much lower applied voltage than would be necessary with a straight electrolysis process. Researchers have reported up to 18% solar to hydrogen efficiencies over short periods. The University of Nevada Las Vegas in conjunction with the UK based firm Hydrogen Solar have developed a prototype of this type of cell using a WO3 photoanode. An on-sun test facility has been constructed by the UNLV Center …

Effect Of Residual Thermal Stresses On Fracture Behavior And Mechanical Properties Of Al Sub 2 O Sub 3/Ni Cermets, Guo Jin Li, Da Ming Chen, Xiao Xian Huang, Jing Kun Guo

Faculty Publications

Effect of residual thermal stresses on fracture behavior and mechanical properties of Al₂O₃/Ni cermets was qualitatively explained by using theory on residual thermal stresses. When Ni particles are located within Al₂O₃ grains or Ni content is relatively low, tensile stresses are exerted at Al₂O₃-Al₂O₃ grain boundary. While fracturing, intergranular fracture is easily produced. When Ni particles are dispersed at Al₂O₃ grain boundary or Ni content is relatively high, compressive stresses are exerted at Al₂O₃-Al₂O₃grain boundary. …

Australian Tractor Test Report No. 41 : The Massey-Ferguson 135, G H. Vasey, F. T. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THE Massey-Ferguson MF-135 is a general purpose tractor of 31 drawbar horsepower. It has 14.9 x 24 pneumatic tyres, and a three-speed gear box with a ratio change which, in the standard model, gives six forward and two reverse gears.

The model tested was also fitted with the optional "Multipower" facility, which gives an "on-the-go" shift to a higher speed for each gear, thus providing 12 forward and four reverse gears.

Australian Tractor Tests : International A554d : Report On Test No. 36 (Farmers' Edition), G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THIS Report is taken from the full Technical Report No. 36; results are shown here in briefer form: fuller explanations are added.

Values quoted may be rounded out to two instead of three significant figures; to this extent the values may differ slightly but not significantly from those shown in the Technical Report.

Australian Tractor Tests : Fordson Farm Major : Report On Test No. 33, G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THIS Report is taken from the full Technical Report No. 33 of this test; test results are shown here in briefer form: fuller explanations are added.

Values quoted may be rounded out to two instead of three significant figures; to this extent the values may differ slightly but not significantly from those shown in the Technical Report.

Graphs of belt test performance, shown in the Technical Report, are not shown here.

Australian Tractor Tests : Report On Test No. 32, G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THIS Report is taken from the full Technical Report No. 32 of this test: test results are shown here in briefer form: fuller explanations are added. Values quoted may be rounded out to two instead of three significant figures:

Australian Tractor Tests : Report On Test No. 34 : Fordson Power Major, G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THIS Report is taken from the full Technical Report No. 34 of this test; test results are shown here in briefer form: fuller explanations are added.

Values quoted may be rounded out to two instead of three significant figures; to this extent the values may differ slightly but not significantly from those shown in the Technical Report

Some values are taken from graphs shown in the Technical Report, which are not shown here.

Australian Tractor Tests : Zetor 50 Super : Report On Test No.35, G H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

T H I S Report is taken from the full Technical Report No. 35; results are shown here in briefer form: fuller explanations are added. Values quoted may be rounded out to two instead of three significant figures.

Tractor Testing In Australia. Part 2, G H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

AUSTRALIAN test procedures, though differing: in some details, and in some ways going further and telling more about the tractor, conform in essentials to overseas standards.

The tests are in four main parts—

(a) the physical properties of the tractor;

(b) the power of the engine, and its stationary outlets—the belt and the p.t.o;

(c) the power on the drawbar when working on a formalised test surface or track;

(d) the reliability of the tractor when running under test, and its condition after the test.

Australian Spark Arrester Tests. Test No. Spa-5 : Caterpillar 3b-2655, W. F. Baillie, G. H. Vasey

Journal of the Department of Agriculture, Western Australia, Series 4

FORMAL tests on spark arresters are conducted by The Tractor Testing Committee* at the Testing Station, Werribee, on behalf of those companies concerned with tractors, engines or spark arresters who wish to have these equipments tested.

The arrester is tested on the engine for which it is specially designed or if this is not convenient (as in this instance) it is tested on an engine having the characteristics and power for which the spark arrester is intended.

Australian Tractor Tests : No. 31, G. H. Vasey, W. F. Baillie

Journal of the Department of Agriculture, Western Australia, Series 4

THIS Report is taken from the full Technical Report No. 31 of this test; test results are shown here in briefer form: fuller explanations are added. Values quoted may be rounded out to two instead of three significant figures; to this extent the values may differ slightly but not significantly from those shown in the Technical Report. Graphs of belt test performance, shown in the Technical Report, are not shown here.

The Design Of A Solar Powered Air Conditioning System For An Albuquerque Office Building, Kuo S. Lee

Mechanical Engineering ETDs

The purpose of this investigation is to predict the performance of a solar powered jet refrigeration system for summer air conditioning, to measure the performance of the solar heat collector at the Bridgers and Paxton building in Albuquerque, and to design a Freon-12 ejector and generator for collection to that collector.